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Sample records for mutual mobile membranes

  1. Mutual diffusion of interacting membrane proteins.

    PubMed Central

    Abney, J R; Scalettar, B A; Owicki, J C

    1989-01-01

    The generalized Stokes-Einstein equation is used, together with the two-dimensional pressure equation, to analyze mutual diffusion in concentrated membrane systems. These equations can be used to investigate the role that both direct and hydrodynamic interactions play in determining diffusive behavior. Here only direct interactions are explicitly incorporated into the theory at high densities; however, both direct and hydrodynamic interactions are analyzed for some dilute solutions. We look at diffusion in the presence of weak attractions, soft repulsions, and hard-core repulsions. It is found that, at low densities, attractions retard mutual diffusion while repulsions enhance it. Mechanistically, attractions tend to tether particles together and oppose the dissipation of gradients or fluctuations in concentration, while repulsions provide a driving force that pushes particles apart. At higher concentrations, changes in the structure of the fluid enhance mutual diffusion even in the presence of attractions. It is shown that the theoretical description of postelectrophoresis relaxation and fluorescence correlation spectroscopy experiments must be modified if interacting systems are studied. The effects of interactions on mutual diffusion coefficients have probably already been seen in postelectrophoresis relaxation experiments. PMID:2775829

  2. Mutual Interactions between Aquaporins and Membrane Components

    PubMed Central

    Martínez-Ballesta, Maria del Carmen; Carvajal, Micaela

    2016-01-01

    In recent years, a number of studies have been focused on the structural evaluation of protein complexes in order to get mechanistic insights into how proteins communicate at the molecular level within the cell. Specific sites of protein-aquaporin interaction have been evaluated and new forms of regulation of aquaporins described, based on these associations. Heterotetramerizations of aquaporin isoforms are considered as novel regulatory mechanisms for plasma membrane (PIPs) and tonoplast (TIPs) proteins, influencing their intrinsic permeability and trafficking dynamics in the adaptive response to changing environmental conditions. However, protein–protein interaction is an extensive theme that is difficult to tackle and new methodologies are being used to study the physical interactions involved. Bimolecular fluorescence complementation and the identification of cross-linked peptides based on tandem mass spectra, that are complementary to other methodologies such as heterologous expression, co-precipitation assays or confocal fluorescence microscopy, are discussed in this review. The chemical composition and the physical characteristics of the lipid bilayer also influence many aspects of membrane aquaporins, including their functionality. The molecular driving forces stabilizing the positions of the lipids around aquaporins could define their activity, thereby altering the conformational properties. Therefore, an integrative approach to the relevance of the membrane-aquaporin interaction to different processes related to plant cell physiology is provided. Finally, it is described how the interactions between aquaporins and copolymer matrixes or biological compounds offer an opportunity for the functional incorporation of aquaporins into new biotechnological advances. PMID:27625676

  3. Mutual Interactions between Aquaporins and Membrane Components.

    PubMed

    Martínez-Ballesta, Maria Del Carmen; Carvajal, Micaela

    2016-01-01

    In recent years, a number of studies have been focused on the structural evaluation of protein complexes in order to get mechanistic insights into how proteins communicate at the molecular level within the cell. Specific sites of protein-aquaporin interaction have been evaluated and new forms of regulation of aquaporins described, based on these associations. Heterotetramerizations of aquaporin isoforms are considered as novel regulatory mechanisms for plasma membrane (PIPs) and tonoplast (TIPs) proteins, influencing their intrinsic permeability and trafficking dynamics in the adaptive response to changing environmental conditions. However, protein-protein interaction is an extensive theme that is difficult to tackle and new methodologies are being used to study the physical interactions involved. Bimolecular fluorescence complementation and the identification of cross-linked peptides based on tandem mass spectra, that are complementary to other methodologies such as heterologous expression, co-precipitation assays or confocal fluorescence microscopy, are discussed in this review. The chemical composition and the physical characteristics of the lipid bilayer also influence many aspects of membrane aquaporins, including their functionality. The molecular driving forces stabilizing the positions of the lipids around aquaporins could define their activity, thereby altering the conformational properties. Therefore, an integrative approach to the relevance of the membrane-aquaporin interaction to different processes related to plant cell physiology is provided. Finally, it is described how the interactions between aquaporins and copolymer matrixes or biological compounds offer an opportunity for the functional incorporation of aquaporins into new biotechnological advances.

  4. Mobility in geometrically confined membranes.

    PubMed

    Domanov, Yegor A; Aimon, Sophie; Toombes, Gilman E S; Renner, Marianne; Quemeneur, François; Triller, Antoine; Turner, Matthew S; Bassereau, Patricia

    2011-08-02

    Lipid and protein lateral mobility is essential for biological function. Our theoretical understanding of this mobility can be traced to the seminal work of Saffman and Delbrück, who predicted a logarithmic dependence of the protein diffusion coefficient (i) on the inverse of the size of the protein and (ii) on the "membrane size" for membranes of finite size [Saffman P, Delbrück M (1975) Proc Natl Acad Sci USA 72:3111-3113]. Although the experimental proof of the first prediction is a matter of debate, the second has not previously been thought to be experimentally accessible. Here, we construct just such a geometrically confined membrane by forming lipid bilayer nanotubes of controlled radii connected to giant liposomes. We followed the diffusion of individual molecules in the tubular membrane using single particle tracking of quantum dots coupled to lipids or voltage-gated potassium channels KvAP, while changing the membrane tube radius from approximately 250 to 10 nm. We found that both lipid and protein diffusion was slower in tubular membranes with smaller radii. The protein diffusion coefficient decreased as much as 5-fold compared to diffusion on the effectively flat membrane of the giant liposomes. Both lipid and protein diffusion data are consistent with the predictions of a hydrodynamic theory that extends the work of Saffman and Delbrück to cylindrical geometries. This study therefore provides strong experimental support for the ubiquitous Saffman-Delbrück theory and elucidates the role of membrane geometry and size in regulating lateral diffusion.

  5. Mobility in geometrically confined membranes

    PubMed Central

    Domanov, Yegor A.; Aimon, Sophie; Toombes, Gilman E. S.; Renner, Marianne; Quemeneur, François; Triller, Antoine; Turner, Matthew S.; Bassereau, Patricia

    2011-01-01

    Lipid and protein lateral mobility is essential for biological function. Our theoretical understanding of this mobility can be traced to the seminal work of Saffman and Delbrück, who predicted a logarithmic dependence of the protein diffusion coefficient (i) on the inverse of the size of the protein and (ii) on the “membrane size” for membranes of finite size [Saffman P, Delbrück M (1975) Proc Natl Acad Sci USA 72:3111—3113]. Although the experimental proof of the first prediction is a matter of debate, the second has not previously been thought to be experimentally accessible. Here, we construct just such a geometrically confined membrane by forming lipid bilayer nanotubes of controlled radii connected to giant liposomes. We followed the diffusion of individual molecules in the tubular membrane using single particle tracking of quantum dots coupled to lipids or voltage-gated potassium channels KvAP, while changing the membrane tube radius from approximately 250 to 10 nm. We found that both lipid and protein diffusion was slower in tubular membranes with smaller radii. The protein diffusion coefficient decreased as much as 5-fold compared to diffusion on the effectively flat membrane of the giant liposomes. Both lipid and protein diffusion data are consistent with the predictions of a hydrodynamic theory that extends the work of Saffman and Delbrück to cylindrical geometries. This study therefore provides strong experimental support for the ubiquitous Saffman–Delbrück theory and elucidates the role of membrane geometry and size in regulating lateral diffusion. PMID:21768336

  6. Mutual control of membrane fission and fusion proteins.

    PubMed

    Peters, Christopher; Baars, Tonie L; Bühler, Susanne; Mayer, Andreas

    2004-11-24

    Membrane fusion and fission are antagonistic reactions controlled by different proteins. Dynamins promote membrane fission by GTP-driven changes of conformation and polymerization state, while SNAREs fuse membranes by forming complexes between t- and v-SNAREs from apposed vesicles. Here, we describe a role of the dynamin-like GTPase Vps1p in fusion of yeast vacuoles. Vps1p forms polymers that couple several t-SNAREs together. At the onset of fusion, the SNARE-activating ATPase Sec18p/NSF and the t-SNARE depolymerize Vps1p and release it from the membrane. This activity is independent of the SNARE coactivator Sec17p/alpha-SNAP and of the v-SNARE. Vps1p release liberates the t-SNAREs for initiating fusion and at the same time disrupts fission activity. We propose that reciprocal control between fusion and fission components exists, which may prevent futile cycles of fission and fusion.

  7. A virtual structure approach to formation control of unicycle mobile robots using mutual coupling

    NASA Astrophysics Data System (ADS)

    Sadowska, Anna; van den Broek, Thijs; Huijberts, Henri; van de Wouw, Nathan; Kostić, Dragan; Nijmeijer, Henk

    2011-11-01

    In this article, the formation control problem for unicycle mobile robots is studied. A distributed virtual structure control strategy with mutual coupling between the robots is proposed. The rationale behind the introduction of the coupling terms is the fact that these introduce additional robustness of the formation with respect to perturbations as compared to typical leader-follower approaches. The applicability of the proposed approach is shown in simulations and experiments with a group of wirelessly controlled mobile robots.

  8. Efficient Multiple Object Tracking Using Mutually Repulsive Active Membranes

    PubMed Central

    Deng, Yi; Coen, Philip; Sun, Mingzhai; Shaevitz, Joshua W.

    2013-01-01

    Studies of social and group behavior in interacting organisms require high-throughput analysis of the motion of a large number of individual subjects. Computer vision techniques offer solutions to specific tracking problems, and allow automated and efficient tracking with minimal human intervention. In this work, we adopt the open active contour model to track the trajectories of moving objects at high density. We add repulsive interactions between open contours to the original model, treat the trajectories as an extrusion in the temporal dimension, and show applications to two tracking problems. The walking behavior of Drosophila is studied at different population density and gender composition. We demonstrate that individual male flies have distinct walking signatures, and that the social interaction between flies in a mixed gender arena is gender specific. We also apply our model to studies of trajectories of gliding Myxococcus xanthus bacteria at high density. We examine the individual gliding behavioral statistics in terms of the gliding speed distribution. Using these two examples at very distinctive spatial scales, we illustrate the use of our algorithm on tracking both short rigid bodies (Drosophila) and long flexible objects (Myxococcus xanthus). Our repulsive active membrane model reaches error rates better than per fly per second for Drosophila tracking and comparable results for Myxococcus xanthus. PMID:23799046

  9. Theoretical comparison of the self diffusion and mutual diffusion of interacting membrane proteins.

    PubMed Central

    Scalettar, B A; Abney, J R; Owicki, J C

    1988-01-01

    Self diffusion and mutual diffusion in two-dimensional membrane systems are analyzed. It is shown that interprotein interactions can produce markedly different density-dependent changes in the diffusion coefficients describing these two processes; the qualitative differences are illustrated by using a theoretical formalism valid for dilute solutions. Results are obtained for three analytical potentials: hard-core repulsions, soft repulsions, and soft repulsions with weak attractions. Self diffusion is inhibited by all three interactions. In contrast, mutual diffusion is inhibited by attractions but is enhanced by repulsions. It is shown that such interaction-dependent differences in self diffusion and mutual diffusion could underlie, among other things, the disparity in protein diffusion coefficients extracted from fluorescence recovery after photobleaching and postelectrophoresis relaxation data. PMID:3413121

  10. Microbial fuel cells and osmotic membrane bioreactors have mutual benefits for wastewater treatment and energy production.

    PubMed

    Hou, Dianxun; Lu, Lu; Ren, Zhiyong Jason

    2016-07-01

    This study demonstrates that microbial fuel cells (MFCs) and osmotic membrane bioreactors (OMBRs) can be mutually beneficial when integrated together for wastewater treatment. When connecting MFCs with OMBRs, the solute buildup increased conductivity and buffer capacity, which greatly increased MFC power density from 3 W/m(3) up to 11.5 W/m(3). In turn, the MFCs conditioned and reduced sludge production and therefore reduced forward osmosis (FO) membrane fouling. The MFC-OMBR equipped with new thin-film composite (TFC) membrane showed excellent organic (>95%) and phosphorus removal (>99%) and therefore maintained effluent sCOD below 20 mg/L. However, the nitrogen removal was limited due to the negative surface charge of the thin-film composite membrane and solution chemistry, which led to higher flux of ammonium toward the OMBR draw solution. Further studies are needed to improve nitrogen removal, reduce fouling, and optimize system integration.

  11. Mobility of membrane-trapped particles

    NASA Astrophysics Data System (ADS)

    Masoud, Hassan; Stone, Howard

    2015-11-01

    The translation or diffusion of particles along membranes or interfaces is of interest because it is a model system for describing basic features of interfacial hydrodynamics. It is also important in cellular signalling in biology and biophysics, and it can be used to deduce the rheological properties of surface films. Here, we consider the translational mobility of spherical and oblate spheroidal particles protruding into the surrounding subphase liquid. Both the subphase and surface film contribute to the resistance experienced by the particle, which is calculated as a function of the degree of protrusion as well as the viscosity contrast between the surface film and the surrounding fluid. The calculations are based on a combination of a perturbation expansion involving the particle shape and the Lorentz reciprocal theorem. It appears that just considering one term of the expansions is in very good agreement with available analytical and numerical results.

  12. Lateral mobility of plasma membrane lipids in dividing Xenopus eggs.

    PubMed

    Tetteroo, P A; Bluemink, J G; Dictus, W J; van Zoelen, E J; de Laat, S W

    1984-07-01

    The lateral mobility of plasma membrane lipids was analyzed during first cleavage of Xenopus laevis eggs by fluorescence photobleaching recovery (FPR) measurements, using the lipid analogs 5-(N-hexadecanoyl)aminofluorescein ("HEDAF") and 5-(N-tetradecanoyl)aminofluorescein ("TEDAF") as probes. The preexisting plasma membrane of the animal side showed an inhomogeneous, dotted fluorescence pattern after labeling and the lateral mobility of both probes used was below the detection limits of the FPR method (D much less than 10(-10) cm2/sec). In contrast, the preexisting plasma membrane of the vegetal side exhibited homogeneous fluorescence and the lateral diffusion coefficient of both probes used was relatively high (HEDAF, D = 2.8 X 10(-8) cm2/sec; TEDAF, D = 2.4 X 10(-8) cm2/sec). In the cleaving egg visible transfer of HEDAF or TEDAF from prelabeled plasma membrane to the new membrane in the furrow did not occur, even on the vegetal side. Upon labeling during cleavage, however, the new membrane was uniformly labeled and both probes were mobile, as in the vegetal preexisting plasma membrane. These data show that the membrane of the dividing Xenopus egg comprises three macrodomains: (i) the animal preexisting plasma membrane; (ii) the vegetal preexisting plasma membrane; (iii) the new furrow membrane.

  13. Modulation of membrane protein lateral mobility by polyphosphates and polyamines.

    PubMed

    Schindler, M; Koppel, D E; Sheetz, M P

    1980-03-01

    The lateral mobility of fluorescein-labeled membrane glycoproteins was measured in whole unlysed erythrocytes and erythrocyte ghosts by the technique of "fluorescence redistribution after fusion." Measurements were made on polyethylene glycol-fused cell pairs in which only one member of the couplet was initially fluorescently labeled. Diffusion coefficients were estimated from the rate of fluorescence redistribution determined from successive scans with a focused laser beam across individual fused pairs. This technique allows for the analysis of diffusion within cell membranes without the possible damaging photochemical events caused by photobleaching. It was found that lateral mobility of erythrocyte proteins can be increased by the addition of polyphosphates (i.e., ATP and 2,3-diphosphoglycerate) and decreased by the addition of organic polyamines (i.e., neomycin and spermine). This control is exerted by these molecules only when they contact the cytoplasmic side of the membrane and is not dependent upon high-energy phosphates. Microviscosity experiments employing diphenylhexatriene demonstrated no changes in membrane lipid state as a function of these reagents. Our results, in conjunction with data on the physical interactions of cytoskeletal proteins, suggest that the diffusion effector molecules alter the lateral mobility of erythrocyte membrane proteins through modifications of interactions in the shell, which is composed of spectrin, actin, and component 4.1.

  14. Modulation of Membrane Protein Lateral Mobility by Polyphosphates and Polyamines

    NASA Astrophysics Data System (ADS)

    Schindler, Melvin; Koppel, Dennis E.; Sheetz, Michael P.

    1980-03-01

    The lateral mobility of fluorescein-labeled membrane glycoproteins was measured in whole unlysed erythrocytes and erythrocyte ghosts by the technique of ``fluorescence redistribution after fusion.'' Measurements were made on polyethylene glycol-fused cell pairs in which only one member of the couplet was initially fluorescently labeled. Diffusion coefficients were estimated from the rate of fluorescence redistribution determined from successive scans with a focused laser beam across individual fused pairs. This technique allows for the analysis of diffusion within cell membranes without the possible damaging photochemical events caused by photobleaching. It was found that lateral mobility of erythrocyte proteins can be increased by the addition of polyphosphates (i.e., ATP and 2,3-diphosphoglycerate) and decreased by the addition of organic polyamines (i.e., neomycin and spermine). This control is exerted by these molecules only when they contact the cytoplasmic side of the membrane and is not dependent upon high-energy phosphates. Microviscosity experiments employing diphenylhexatriene demonstrated no changes in membrane lipid state as a function of these reagents. Our results, in conjunction with data on the physical interactions of cytoskeletal proteins, suggest that the diffusion effector molecules alter the lateral mobility of erythrocyte membrane proteins through modifications of interactions in the shell, which is composed of spectrin, actin, and component 4.1.

  15. Tuning membrane protein mobility by confinement into nanodomains

    NASA Astrophysics Data System (ADS)

    Karner, Andreas; Nimmervoll, Benedikt; Plochberger, Birgit; Klotzsch, Enrico; Horner, Andreas; Knyazev, Denis G.; Kuttner, Roland; Winkler, Klemens; Winter, Lukas; Siligan, Christine; Ollinger, Nicole; Pohl, Peter; Preiner, Johannes

    2017-03-01

    High-speed atomic force microscopy (HS-AFM) can be used to visualize function-related conformational changes of single soluble proteins. Similar studies of single membrane proteins are, however, hampered by a lack of suitable flat, non-interacting membrane supports and by high protein mobility. Here we show that streptavidin crystals grown on mica-supported lipid bilayers can be used as porous supports for membranes containing biotinylated lipids. Using SecYEG (protein translocation channel) and GlpF (aquaglyceroporin), we demonstrate that the platform can be used to tune the lateral mobility of transmembrane proteins to any value within the dynamic range accessible to HS-AFM imaging through glutaraldehyde-cross-linking of the streptavidin. This allows HS-AFM to study the conformation or docking of spatially confined proteins, which we illustrate by imaging GlpF at sub-molecular resolution and by observing the motor protein SecA binding to SecYEG.

  16. Mutual structural effect of bilirubin and model membranes by vibrational circular dichroism.

    PubMed

    Novotná, Pavlína; Goncharova, Iryna; Urbanová, Marie

    2014-03-01

    In this study, vibrational circular dichroism (VCD) spectroscopy was employed for the first time to study the bilirubin (BR) interaction with model membranes and models for membrane proteins. An enantioselective interaction of BR with zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and sphingomyelin (SPM) liposomes was observed by VCD and electronic circular dichroism (ECD) complemented by absorption and fluorescence spectroscopy. The M-form of BR was preferentially recognized in the BR/DMPC system at concentration above 1×10(-4)M, for lower concentrations the P-form of BR was recognized by the DMPC liposomes. The VCD spectra also showed that the SPM liposomes, which represent the main component of nerve cell membrane, were significantly more disturbed by the presence of BR than the DMPC liposomes-a stable association with a strong VCD signal was observed providing the explanations for the supposed BR neurotoxicity. The effect of time and pH on the BR/DMPC or SPM liposome systems was shown to be essential while the effect of temperature in the range of 15-70°C was negligible demonstrating the surprisingly high temperature stability of BR when interacting with the studied membranes. The influence of a membrane protein was tested on a model consisting of poly-l-arginine (PLAG) bound in the α-helical form to the surface of 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) liposomes and sodium dodecyl sulfate micelles. VCD and also ECD spectra showed that a variety of BR diastereoisomers interacted with PLAG in such systems. In a system of PLAG with micelles composed of sodium dodecyl sulfate, the M-form of bound BR was observed. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. CHARMM-GUI HMMM Builder for Membrane Simulations with the Highly Mobile Membrane-Mimetic Model.

    PubMed

    Qi, Yifei; Cheng, Xi; Lee, Jumin; Vermaas, Josh V; Pogorelov, Taras V; Tajkhorshid, Emad; Park, Soohyung; Klauda, Jeffery B; Im, Wonpil

    2015-11-17

    Slow diffusion of the lipids in conventional all-atom simulations of membrane systems makes it difficult to sample large rearrangements of lipids and protein-lipid interactions. Recently, Tajkhorshid and co-workers developed the highly mobile membrane-mimetic (HMMM) model with accelerated lipid motion by replacing the lipid tails with small organic molecules. The HMMM model provides accelerated lipid diffusion by one to two orders of magnitude, and is particularly useful in studying membrane-protein associations. However, building an HMMM simulation system is not easy, as it requires sophisticated treatment of the lipid tails. In this study, we have developed CHARMM-GUI HMMM Builder (http://www.charmm-gui.org/input/hmmm) to provide users with ready-to-go input files for simulating HMMM membrane systems with/without proteins. Various lipid-only and protein-lipid systems are simulated to validate the qualities of the systems generated by HMMM Builder with focus on the basic properties and advantages of the HMMM model. HMMM Builder supports all lipid types available in CHARMM-GUI and also provides a module to convert back and forth between an HMMM membrane and a full-length membrane. We expect HMMM Builder to be a useful tool in studying membrane systems with enhanced lipid diffusion. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  18. Determination of electrolyte friction from measurements of the tracer diffusion coefficients, mutual diffusion coefficients, and electrophoretic mobilities of charged spheres

    NASA Astrophysics Data System (ADS)

    Gorti, Sridhar; Plank, Lindsay; Ware, B. R.

    1984-07-01

    The technique of fluorescence recovery after photobleaching has been used to measure the tracer diffusion coefficient of fluorescein-labeled charged polystyrene spheres in dilute solutions as a function of solution ionic strength. As the ratio of the particle radius (a) to the Debye-Hückel screening length (κ-1) was varied from 13 to 0.6, a 20% reduction in tracer diffusion coefficient was observed. The mutual diffusion coefficient, measured by quasielastic light scattering, increased as κa was reduced, demonstrating the dominant effect of thermodynamic factors on this parameter. The tracer data have been compared with theoretical predictions of other workers describing the influence of small-ion interactions with a charge sphere on its translational friction. The theoretical results of Schurr, and Booth, involve an explicit dependence on the electrokinetic charge of the sphere and yield estimates of this parameter (by least squares) which are significantly smaller than those obtained from laser Doppler electrophoretic light scattering results for the electrophoretic mobility of the labeled spheres. Approximations in the theoretical analyses are expected to account for these discrepancies.

  19. Reduced Lateral Mobility of Lipids and Proteins in Crowded Membranes

    PubMed Central

    Goose, Joseph E.; Sansom, Mark S. P.

    2013-01-01

    Coarse-grained molecular dynamics simulations of the E. coli outer membrane proteins FhuA, LamB, NanC, OmpA and OmpF in a POPE/POPG (3∶1) bilayer were performed to characterise the diffusive nature of each component of the membrane. At small observation times (<10 ns) particle vibrations dominate phospholipid diffusion elevating the calculated values from the longer time-scale bulk value (>50 ns) of 8.5×10−7 cm2 s−1. The phospholipid diffusion around each protein was found to vary based on distance from protein. An asymmetry in the diffusion of annular lipids in the inner and outer leaflets was observed and correlated with an asymmetry in charged residues in the vicinity of the inner and outer leaflet head-groups. Protein rotational and translational diffusion were also found to vary with observation time and were inversely correlated with the radius of gyration of the protein in the plane of the bilayer. As the concentration of protein within the bilayer was increased, the overall mobility of the membrane decreased reflected in reduced lipid diffusion coefficients for both lipid and protein components. The increase in protein concentration also resulted in a decrease in the anomalous diffusion exponent α of the lipid. Formation of extended clusters and networks of proteins led to compartmentalisation of lipids in extreme cases. PMID:23592975

  20. Spacesuit Water Membrane Evaporator Integration with the ISS Extravehicular Mobility

    NASA Technical Reports Server (NTRS)

    Margiott, Victoria; Boyle, Robert

    2014-01-01

    NASA has developed a Solid Water Membrane Evaporation (SWME) to provide cooling for the next generation spacesuit. One approach to increasing the TRL of the system is to incorporate this hardware with the existing EMU. Several integration issues were addressed to support a potential demonstration of the SWME with the existing EMU. Systems analysis was performed to assess the capability of the SWME to maintain crewmember cooling and comfort as a replacement for sublimation. The materials of the SWME were reviewed to address compatibility with the EMU. Conceptual system placement and integration with the EMU via an EVA umbilical system to ensure crew mobility and Airlock egress were performed. A concept of operation for EVA use was identified that is compatible with the existing system. This concept is extensible as a means to provide cooling for the existing EMU. The cooling system of one of the EMUs on orbit has degraded, with the root cause undetermined. Should there be a common cause resident on ISS, this integration could provide a means to recover cooling capability for EMUs on orbit.

  1. Investigation of humidity control via membrane separation for advanced Extravehicular Mobility Unit (EMU) application

    NASA Technical Reports Server (NTRS)

    Newbold, D. D.; Ray, R. J.; Pledger, W. A.; Mccray, S. B.; Brown, M. F.

    1989-01-01

    This paper describes the development of a membrane-based process for dehumidifying the Extravehicular Mobility Unit (EMU). The membrane process promises to be smaller, lighter, and more energy efficient than the other technologies for dehumidification. The dehydration membranes were tested for 90 days at conditions expected to be present in the EMU. The results of these tests indicate that membrane-based technology can effectively control humidity in the EMU.

  2. Investigation of humidity control via membrane separation for advanced Extravehicular Mobility Unit (EMU) application

    NASA Technical Reports Server (NTRS)

    Newbold, D. D.; Ray, R. J.; Pledger, W. A.; Mccray, S. B.; Brown, M. F.

    1989-01-01

    This paper describes the development of a membrane-based process for dehumidifying the Extravehicular Mobility Unit (EMU). The membrane process promises to be smaller, lighter, and more energy efficient than the other technologies for dehumidification. The dehydration membranes were tested for 90 days at conditions expected to be present in the EMU. The results of these tests indicate that membrane-based technology can effectively control humidity in the EMU.

  3. Differential regulation of the lateral mobility of plasma membrane phospholipids by the extracellular matrix and cholesterol.

    PubMed

    Ramprasad, O G; Rangaraj, Nandini; Srinivas, G; Thiery, Jean Paul; Dufour, Sylvie; Pande, Gopal

    2008-05-01

    In this study, we compared qualitative and quantitative changes in the lateral mobility of phospholipid molecules in the plasma membrane of intact cells under various conditions of specific interaction of integrins in the cell membrane with two extracellular matrix (ECM) components viz. fibronectin (FN) and laminin (LN). We found a strong and specific correlation between the lower lateral mobility of phosphatidylcholine (PC) and higher lateral mobility of phosphatidylethanolamine (PE) when cells were expressing high levels of alpha5beta1 integrin and thus were adherent and motile on FN. The interaction between PC and FN in alpha5 integrin expressing cells was aided by the strong affinity of alpha5 integrin to the FN matrix. Cholesterol was involved in regulating the lateral mobility of PC to a great extent and of PE to a lesser extent without affecting the overall microviscosity of the plasma membrane or the distribution of caveolin-marked domains. The distribution and mobility of PC and PE molecules in the lamellipodial regions differed from that in the rest of the membrane and also in the more motile and in the less motile cells. We propose that these differences in distribution of PC and PE in different regions of cell membrane and their respective lateral mobility are observed due to the specific interaction of PC molecules with FN molecules in the ECM. Our results outline a new role of integrin-matrix interactions in the regulation of membrane phospholipid behavior. (c) 2007 Wiley-Liss, Inc.

  4. Fluorescence Recovery After Photobleaching Analysis of the Diffusional Mobility of Plasma Membrane Proteins: HER3 Mobility in Breast Cancer Cell Membranes.

    PubMed

    Sarkar, Mitul; Koland, John G

    2016-01-01

    The fluorescence recovery after photobleaching (FRAP) method is a straightforward means of assessing the diffusional mobility of membrane-associated proteins that is readily performed with current confocal microscopy instrumentation. We describe here the specific application of the FRAP method in characterizing the lateral diffusion of genetically encoded green fluorescence protein (GFP)-tagged plasma membrane receptor proteins. The method is exemplified in an examination of whether the previously observed segregation of the mammalian HER3 receptor protein in discrete plasma membrane microdomains results from its physical interaction with cellular entities that restrict its mobility. Our FRAP measurements of the diffusional mobility of GFP-tagged HER3 reporters expressed in MCF7 cultured breast cancer cells showed that despite the observed segregation of HER3 receptors within plasma membrane microdomains their diffusion on the macroscopic scale is not spatially restricted. Thus, in FRAP analyses of various HER3 reporters a near-complete recovery of fluorescence after photobleaching was observed, indicating that HER3 receptors are not immobilized by long-lived physical interactions with intracellular species. An examination of HER3 proteins with varying intracellular domain sequence truncations also indicated that a proposed formation of oligomeric HER3 networks, mediated by physical interactions involving specific HER3 intracellular domain sequences, either does not occur or does not significantly reduce HER3 mobility on the macroscopic scale.

  5. Hydrodynamic mobility of a solid particle near a spherical elastic membrane. II. Asymmetric motion

    NASA Astrophysics Data System (ADS)

    Daddi-Moussa-Ider, Abdallah; Lisicki, Maciej; Gekle, Stephan

    2017-05-01

    In this paper, we derive analytical expressions for the leading-order hydrodynamic mobility of a small solid particle undergoing motion tangential to a nearby large spherical capsule whose membrane possesses resistance toward shearing and bending. Together with the results obtained in the first part [Daddi-Moussa-Ider and Gekle, Phys. Rev. E 95, 013108 (2017), 10.1103/PhysRevE.95.013108], where the axisymmetric motion perpendicular to the capsule membrane is considered, the solution of the general mobility problem is thus determined. We find that shearing resistance induces a low-frequency peak in the particle self-mobility, resulting from the membrane normal displacement in the same way, although less pronounced, to what has been observed for the axisymmetric motion. In the zero-frequency limit, the self-mobility correction near a hard sphere is recovered only if the membrane has a nonvanishing resistance toward shearing. We further compute the in-plane mean-square displacement of a nearby diffusing particle, finding that the membrane induces a long-lasting subdiffusive regime. Considering capsule motion, we find that the correction to the pair-mobility function is solely determined by membrane shearing properties. Our analytical calculations are compared and validated with fully resolved boundary integral simulations where a very good agreement is obtained.

  6. Hydrodynamic mobility of a solid particle near a spherical elastic membrane. II. Asymmetric motion.

    PubMed

    Daddi-Moussa-Ider, Abdallah; Lisicki, Maciej; Gekle, Stephan

    2017-05-01

    In this paper, we derive analytical expressions for the leading-order hydrodynamic mobility of a small solid particle undergoing motion tangential to a nearby large spherical capsule whose membrane possesses resistance toward shearing and bending. Together with the results obtained in the first part [Daddi-Moussa-Ider and Gekle, Phys. Rev. E 95, 013108 (2017)2470-004510.1103/PhysRevE.95.013108], where the axisymmetric motion perpendicular to the capsule membrane is considered, the solution of the general mobility problem is thus determined. We find that shearing resistance induces a low-frequency peak in the particle self-mobility, resulting from the membrane normal displacement in the same way, although less pronounced, to what has been observed for the axisymmetric motion. In the zero-frequency limit, the self-mobility correction near a hard sphere is recovered only if the membrane has a nonvanishing resistance toward shearing. We further compute the in-plane mean-square displacement of a nearby diffusing particle, finding that the membrane induces a long-lasting subdiffusive regime. Considering capsule motion, we find that the correction to the pair-mobility function is solely determined by membrane shearing properties. Our analytical calculations are compared and validated with fully resolved boundary integral simulations where a very good agreement is obtained.

  7. Hydrodynamic mobility of a solid particle near a spherical elastic membrane: Axisymmetric motion.

    PubMed

    Daddi-Moussa-Ider, Abdallah; Gekle, Stephan

    2017-01-01

    We use the image solution technique to compute the leading order frequency-dependent self-mobility function of a small solid particle moving perpendicular to the surface of a spherical capsule whose membrane possesses shearing and bending rigidities. Comparing our results with those obtained earlier for an infinitely extended planar elastic membrane, we find that membrane curvature leads to the appearance of a prominent additional peak in the mobility. This peak is attributed to the fact that the shear resistance of the curved membrane involves a contribution from surface-normal displacements, which is not the case for planar membranes. In the vanishing frequency limit, the particle self-mobility near a no-slip hard sphere is recovered only when the membrane possesses a nonvanishing resistance toward shearing. We further investigate capsule motion, finding that the pair-mobility function is solely determined by membrane shearing properties. Our analytical predictions are validated by fully resolved boundary integral simulations where a very good agreement is obtained.

  8. Hydrodynamic mobility of a solid particle near a spherical elastic membrane: Axisymmetric motion

    NASA Astrophysics Data System (ADS)

    Daddi-Moussa-Ider, Abdallah; Gekle, Stephan

    2017-01-01

    We use the image solution technique to compute the leading order frequency-dependent self-mobility function of a small solid particle moving perpendicular to the surface of a spherical capsule whose membrane possesses shearing and bending rigidities. Comparing our results with those obtained earlier for an infinitely extended planar elastic membrane, we find that membrane curvature leads to the appearance of a prominent additional peak in the mobility. This peak is attributed to the fact that the shear resistance of the curved membrane involves a contribution from surface-normal displacements, which is not the case for planar membranes. In the vanishing frequency limit, the particle self-mobility near a no-slip hard sphere is recovered only when the membrane possesses a nonvanishing resistance toward shearing. We further investigate capsule motion, finding that the pair-mobility function is solely determined by membrane shearing properties. Our analytical predictions are validated by fully resolved boundary integral simulations where a very good agreement is obtained.

  9. Independent mobility of proteins and lipids in the plasma membrane of Escherichia coli

    PubMed Central

    Nenninger, Anja; Mastroianni, Giulia; Robson, Alexander; Lenn, Tchern; Xue, Quan; Leake, Mark C; Mullineaux, Conrad W

    2014-01-01

    Summary Fluidity is essential for many biological membrane functions. The basis for understanding membrane structure remains the classic Singer-Nicolson model, in which proteins are embedded within a fluid lipid bilayer and able to diffuse laterally within a sea of lipid. Here we report lipid and protein diffusion in the plasma membrane of live cells of the bacterium Escherichia coli, using Fluorescence Recovery after Photobleaching (FRAP) and Total Internal Reflection Fluorescence (TIRF) microscopy to measure lateral diffusion coefficients. Lipid and protein mobility within the membrane were probed by visualizing an artificial fluorescent lipid and a simple model membrane protein consisting of a single membrane-spanning alpha-helix with a Green Fluorescent Protein (GFP) tag on the cytoplasmic side. The effective viscosity of the lipid bilayer is strongly temperature-dependent, as indicated by changes in the lipid diffusion coefficient. Surprisingly, the mobility of the model protein was unaffected by changes in the effective viscosity of the bulk lipid, and TIRF microscopy indicates that it clusters in segregated, mobile domains. We suggest that this segregation profoundly influences the physical behaviour of the protein in the membrane, with strong implications for bacterial membrane function and bacterial physiology. PMID:24735432

  10. Mobility functions of a spheroidal particle near a planar elastic membrane

    NASA Astrophysics Data System (ADS)

    Daddi-Moussa-Ider, Abdallah; Lisicki, Maciej; Gekle, Stephan

    2016-11-01

    Using an analytical theory, we compute the leading order corrections to the translational, rotational and translation-rotation coupling mobilities of a prolate spheroid immersed in a Newtonian fluid and moving nearby an elastic cell membrane. The corrections are expressed in terms of the spheroid-to-membrane distance, spheroid orientation and the characteristic frequencies associated with membrane shearing and bending. We find that the corrections to the translation-rotation coupling mobility are primarily determined by bending resistance whereas shearing elasticity manifests itself in a more pronounced way in the rotational mobility. We further demonstrate the validity of the analytical approximation by close comparison with boundary integral simulations of a truly extended spheroidal particle. The analytical calculations are found to be in a good agreement with the numerical simulations over the whole range of the applied frequencies.

  11. Mechanics, morphology, and mobility in stratum corneum membranes

    NASA Astrophysics Data System (ADS)

    Olmsted, Peter; Das, Chinmay; Noro, Massimo

    2012-02-01

    The stratum corneum is the outermost layer of skin, and serves as a protective barrier against external agents, and to control moisture. It comprises keratin bodies (corneocytes) embedded in a matrix of lipid bilayers. Unlike the more widely studied phospholipid bilayers, the SC bilayers are typically in a gel-like state. Moreover, the SC membrane composition is radically different from more fluid counterparts: it comprises single tailed fatty acids, ceramides, and cholesterol; with many distinct ceramides possessing different lengths of tails, and always with two tails of different lengths. I will present insight from computer simulations into the morphology, mechanical properties, and diffusion (barrier) properties of these highly heterogeneous membranes. Our results provide some clue as to the design principles for the SC membrane, and is an excellent example of the use of wide polydispersity by natural systems.

  12. Intraguild mutualism.

    PubMed

    Crowley, Philip H; Cox, John J

    2011-12-01

    Although studies of species linked by a common resource (i.e. ecological guilds) have so far mainly focused on competition and predation, guilds are also good places to find mutualism. In this review we consider some three- and four-species community modules to illustrate examples of wide relevance. Mutualism arises from various direct and indirect trophic and non-trophic interactions between species--and within modules both with and without intraguild predation. Species removal and augmentation experiments, other manipulations, direct measurements, and path-analytic methods can determine the presence and intensity of mutualism within guilds. Such studies, particularly when associated with existing theory and new theoretical development, can help advance an interaction-based approach to community analysis that recognizes linkages among mutualism, predation and competition in natural systems.

  13. Drug binding and mobility relating to the thermal fluctuation in fluid lipid membranes

    NASA Astrophysics Data System (ADS)

    Okamura, Emiko; Yoshii, Noriyuki

    2008-12-01

    Drug binding and mobility in fluid lipid bilayer membranes are quantified in situ by using the multinuclear solution NMR combined with the pulsed-field-gradient technique. One-dimensional and pulsed-field-gradient F19 and H1 NMR signals of an anticancer drug, 5-fluorouracil (5FU) are analyzed at 283-313 K in the presence of large unilamellar vesicles (LUVs) of egg phosphatidylcholine (EPC) as model cell membranes. The simultaneous observation of the membrane-bound and free 5FU signals enables to quantify in what amount of 5FU is bound to the membrane and how fast 5FU is moving within the membrane in relation to the thermal fluctuation of the soft, fluid environment. It is shown that the mobility of membrane-bound 5FU is slowed down by almost two orders of magnitude and similar to the lipid movement in the membrane, the movement closely related to the intramembrane fluidity. The mobility of 5FU and EPC is, however, not similar at 313 K; the 5FU movement is enhanced in the membrane as a result of the loose binding of 5FU in the lipid matrices. The membrane-bound fraction of 5FU is ˜0.1 and almost unaltered over the temperature range examined. It is also independent of the 5FU concentration from 2 to 30 mM with respect to the 40-50 mM LUV. The free energy of the 5FU binding is estimated at -4 to -2 kJ/mol, the magnitude always close to the thermal fluctuation, 2.4-2.6 kJ/mol.

  14. Significance of protein crowding, order and mobility for photosynthetic membrane functions.

    PubMed

    Kirchhoff, Helmut

    2008-10-01

    Natural photosynthesis requires diffusion-based processes either for the functional communication of protein complexes or for the adaptation, maintenance and biogenesis of the photosynthetic apparatus. A conceptual problem with lateral diffusion in photosynthetic membranes arises from the fact that these membranes are densely packed with membrane integral protein complexes (molecular crowding). Theoretical analysis of PQ (plastoquinone) and protein diffusion in higher plant grana thylakoids reveal very inefficient lateral diffusion. In contrast, measurement of protein mobility in grana membranes shows that a fraction of protein complexes can move surprisingly fast. It is postulated that organization of protein complexes in supercomplexes and large-scale ordering of Photosystem II and light-harvesting complex II could be strategies for the optimization of diffusion in crowded thylakoid membranes.

  15. [Effect of the mobility of gate charges on volt-ampere characteristics of excitable membranes].

    PubMed

    Radchenko, A N

    1996-01-01

    An assumption on nature of the gate charges and known data on gate changes mobility allow to deduce the volt-ampere characteristics of ionic channels and the same for membrane. Model research shows that the volt-ampere curve shape depends on gate charges mobility. Its reduction and the followed gate charges immobilization during membrane excitation process are expressed as the changes of volt-ampere curves. These changes might be to specify as the fast components of the inactivation process. A number critical values of the gate charges mobility are calculated which are important for the functions of memory (hysteresis) and excitation (negative resistance). The coincidence of values of biased charge in model and experiment is noted. The formulae that are drown are compared with Hodgkin-Huxley approximations.

  16. The petrogenesis of anorogenic felsic magmas and AMCG suites: Insights on element mobility and mutual cryptic contamination from polythermal experiments

    NASA Astrophysics Data System (ADS)

    Martin, Robert F.

    2012-10-01

    The close association of mantle-derived mafic rocks and crust-derived felsic rocks in AMCG suites the world over is now interpreted in terms of delamination of the lithospheric keel of an orogen within a short time after the cessation of a major collision. The stage is set for the ascent of an asthenospheric diapir, which is accompanied by the ascent of a stream of H2O-CO2 representing regional degassing of the mantle in the ensuing extensional setting. The crust gets variably metasomatized prior to melting, and this episode of melting seems to involve almost complete melting rather than the expected films of leucosome. Results of polythermal experiments with a large array of target rocks (pulverized) + H2O show that it is possible to mobilize the major elements K, Na, Al, Si and Fe such that the transported fractions resembles an A-type granite or syenite. The open-system process increases in efficiency with increasing temperature and increasing pressure. A stream of such fluid interacting with gabbro or basic magma could create anorthositic and ultrabasic assemblages that are candidates for contamination of pools of basic magma in the uppermost mantle and lower crust. The same stream continues its buoyant rise and makes over the sterile granulitic lower and middle crust into a geochemically fertile protolith for the generation of A-type felsic magmas by wholesale anatexis.

  17. Heterogeneity of membrane phospholipid mobility in endothelial cells depends on cell substrate

    NASA Astrophysics Data System (ADS)

    Nakache, M.; Schreiber, A. B.; Gaub, H.; McConnell, H. M.

    1985-09-01

    Cellular growth control and differentiation have been shown to be dependent on both cell-cell and cell-substrate contacts1. Interactions of cells with extracellular material are critical events during embryonic development and maintenance of tissue function2. Plasma membrane receptors have been described for components of the extracellular matrix such as fibronectin, laminin and various collagen types3. Transmembrane signalling has been shown to be influenced by the lateral mobilities of the plasma membrane constituents4. The interaction of cells with their extracellular matrix could thus have a significant effect on the mobility properties of the plasma membrane components5. Here we have studied the dynamic properties of fluorescent membrane phospholipids in bovine endothelial cells using fluorescence recovery after photo bleaching measurements. At this molecular level we find that the phospholipid lateral diffusion coefficient is dependent on the substrate upon which cells are allowed to adhere (collagen, fibronectin or a natural basement membrane) and on the topography of the cell (basal versus apical plasma membrane).

  18. Confined Mobility of TonB and FepA in Escherichia coli Membranes

    PubMed Central

    Lill, Yoriko; Jordan, Lorne D.; Smallwood, Chuck R.; Newton, Salete M.; Lill, Markus A.; Klebba, Phillip E.; Ritchie, Ken

    2016-01-01

    The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent transporters (TBDTs) and requires interaction with the inner membrane protein TonB. Here we have imaged the mobility of the ferric enterobactin transporter FepA and TonB by tracking them in the membranes of live E. coli with single-molecule resolution at time-scales ranging from milliseconds to seconds. We employed simple simulations to model/analyze the lateral diffusion in the membranes of E.coli, to take into account both the highly curved geometry of the cell and artifactual effects expected due to finite exposure time imaging. We find that both molecules perform confined lateral diffusion in their respective membranes in the absence of ligand with FepA confined to a region 0.180−0.007+0.006 μm in radius in the outer membrane and TonB confined to a region 0.266−0.009+0.007 μm in radius in the inner membrane. The diffusion coefficient of these molecules on millisecond time-scales was estimated to be 21−5+9 μm2/s and 5.4−0.8+1.5 μm2/s for FepA and TonB, respectively, implying that each molecule is free to diffuse within its domain. Disruption of the inner membrane potential, deletion of ExbB/D from the inner membrane, presence of ligand or antibody to FepA and disruption of the MreB cytoskeleton was all found to further restrict the mobility of both molecules. Results are analyzed in terms of changes in confinement size and interactions between the two proteins. PMID:27935943

  19. Confined Mobility of TonB and FepA in Escherichia coli Membranes.

    PubMed

    Lill, Yoriko; Jordan, Lorne D; Smallwood, Chuck R; Newton, Salete M; Lill, Markus A; Klebba, Phillip E; Ritchie, Ken

    2016-01-01

    The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent transporters (TBDTs) and requires interaction with the inner membrane protein TonB. Here we have imaged the mobility of the ferric enterobactin transporter FepA and TonB by tracking them in the membranes of live E. coli with single-molecule resolution at time-scales ranging from milliseconds to seconds. We employed simple simulations to model/analyze the lateral diffusion in the membranes of E.coli, to take into account both the highly curved geometry of the cell and artifactual effects expected due to finite exposure time imaging. We find that both molecules perform confined lateral diffusion in their respective membranes in the absence of ligand with FepA confined to a region [Formula: see text] μm in radius in the outer membrane and TonB confined to a region [Formula: see text] μm in radius in the inner membrane. The diffusion coefficient of these molecules on millisecond time-scales was estimated to be [Formula: see text] μm2/s and [Formula: see text] μm2/s for FepA and TonB, respectively, implying that each molecule is free to diffuse within its domain. Disruption of the inner membrane potential, deletion of ExbB/D from the inner membrane, presence of ligand or antibody to FepA and disruption of the MreB cytoskeleton was all found to further restrict the mobility of both molecules. Results are analyzed in terms of changes in confinement size and interactions between the two proteins.

  20. High lateral mobility of endogenous and transfected alkaline phosphatase: a phosphatidylinositol-anchored membrane protein

    PubMed Central

    1987-01-01

    The lateral mobility of alkaline phosphatase (AP) in the plasma membrane of osteoblastic and nonosteoblastic cells was estimated by fluorescence redistribution after photobleaching in embryonic and in tumor cells, in cells that express AP naturally, and in cells transfected with an expression vector containing AP cDNA. The diffusion coefficient (D) and the mobile fraction, estimated from the percent recovery (%R), were found to be cell-type dependent ranging from (0.58 +/- 0.16) X 10(-9) cm2s-1 and 73.3 +/- 10.5 in rat osteosarcoma cells ROS 17/2.8 to (1.77 +/- 0.51) X 10(-9) cm2s-1 and 82.8 +/- 2.5 in rat osteosarcoma cells UMR106. Similar values of D greater than or equal to 10(-9) cm2s-1 with approximately 80% recovery were also found in fetal rat calvaria cells, transfected skin fibroblasts, and transfected AP- negative osteosarcoma cells ROS 25/1. These values of D are many times greater than "typical" values for membrane proteins, coming close to those of membrane lipid in fetal rat calvaria and ROS 17/2.8 cells (D = [4(-5)] X 10(-9) cm2s-1 with 75-80% recovery), estimated with the hexadecanoyl aminofluorescein probe. In all cell types, phosphatidylinositol (PI)-specific phospholipase C released 60-90% of native and transfection-expressed AP, demonstrating that, as in other tissue types, AP in these cells is anchored in the membrane via a linkage to PI. These results indicate that the transfected cells used in this study possess the machinery for AP insertion into the membrane and its binding to PI. The fast AP mobility appears to be an intrinsic property of the way the protein is anchored in the membrane, a conclusion with general implications for the understanding of the slow diffusion of other membrane proteins. PMID:2889741

  1. Outer Hair Cell Lateral Wall Structure Constrains the Mobility of Plasma Membrane Proteins

    PubMed Central

    Yamashita, Tetsuji; Hakizimana, Pierre; Wu, Siva; Hassan, Ahmed; Jacob, Stefan; Temirov, Jamshid; Fang, Jie; Mellado-Lagarde, Marcia; Gursky, Richard; Horner, Linda; Leibiger, Barbara; Leijon, Sara; Centonze, Victoria E.; Berggren, Per-Olof; Frase, Sharon; Auer, Manfred; Brownell, William E.; Fridberger, Anders; Zuo, Jian

    2015-01-01

    Nature’s fastest motors are the cochlear outer hair cells (OHCs). These sensory cells use a membrane protein, Slc26a5 (prestin), to generate mechanical force at high frequencies, which is essential for explaining the exquisite hearing sensitivity of mammalian ears. Previous studies suggest that Slc26a5 continuously diffuses within the membrane, but how can a freely moving motor protein effectively convey forces critical for hearing? To provide direct evidence in OHCs for freely moving Slc26a5 molecules, we created a knockin mouse where Slc26a5 is fused with YFP. These mice and four other strains expressing fluorescently labeled membrane proteins were used to examine their lateral diffusion in the OHC lateral wall. All five proteins showed minimal diffusion, but did move after pharmacological disruption of membrane-associated structures with a cholesterol-depleting agent and salicylate. Thus, our results demonstrate that OHC lateral wall structure constrains the mobility of plasma membrane proteins and that the integrity of such membrane-associated structures are critical for Slc26a5’s active and structural roles. The structural constraint of membrane proteins may exemplify convergent evolution of cellular motors across species. Our findings also suggest a possible mechanism for disorders of cholesterol metabolism with hearing loss such as Niemann-Pick Type C diseases. PMID:26352669

  2. Characterization of Membrane Protein-Lipid Interactions by Mass Spectrometry Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Cong, Xiao; Liu, Wen; Laganowsky, Arthur

    2017-04-01

    Lipids in the biological membrane can modulate the structure and function of integral and peripheral membrane proteins. Distinguishing individual lipids that bind selectively to membrane protein complexes from an ensemble of lipid-bound species remains a daunting task. Recently, ion mobility mass spectrometry (IM-MS) has proven to be invaluable for interrogating the interactions between protein and individual lipids, where the complex undergoes collision induced unfolding followed by quantification of the unfolding pathway to assess the effect of these interactions. However, gas-phase unfolding experiments for membrane proteins are typically performed on the entire ensemble ( apo and lipid bound species), raising uncertainty to the contribution of individual lipids and the species that are ejected in the unfolding process. Here, we describe the application of mass spectrometry ion mobility mass spectrometry (MS-IM-MS) for isolating ions corresponding to lipid-bound states of a model integral membrane protein, ammonia channel (AmtB) from Escherichia coli. Free of ensemble effects, MS-IM-MS reveals that bound lipids are ejected as neutral species; however, no correlation was found between the lipid-induced stabilization of complex and their equilibrium binding constants. In comparison to data obtained by IM-MS, there are surprisingly limited differences in stability measurements from IM-MS and MS-IM-MS. The approach described here to isolate ions of membrane protein complexes will be useful for other MS methods, such as surface induced dissociation or collision induced dissociation to determine the stoichiometry of hetero-oligomeric membrane protein complexes.

  3. Characterization of Membrane Protein-Lipid Interactions by Mass Spectrometry Ion Mobility Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Cong, Xiao; Liu, Wen; Laganowsky, Arthur

    2016-12-01

    Lipids in the biological membrane can modulate the structure and function of integral and peripheral membrane proteins. Distinguishing individual lipids that bind selectively to membrane protein complexes from an ensemble of lipid-bound species remains a daunting task. Recently, ion mobility mass spectrometry (IM-MS) has proven to be invaluable for interrogating the interactions between protein and individual lipids, where the complex undergoes collision induced unfolding followed by quantification of the unfolding pathway to assess the effect of these interactions. However, gas-phase unfolding experiments for membrane proteins are typically performed on the entire ensemble (apo and lipid bound species), raising uncertainty to the contribution of individual lipids and the species that are ejected in the unfolding process. Here, we describe the application of mass spectrometry ion mobility mass spectrometry (MS-IM-MS) for isolating ions corresponding to lipid-bound states of a model integral membrane protein, ammonia channel (AmtB) from Escherichia coli. Free of ensemble effects, MS-IM-MS reveals that bound lipids are ejected as neutral species; however, no correlation was found between the lipid-induced stabilization of complex and their equilibrium binding constants. In comparison to data obtained by IM-MS, there are surprisingly limited differences in stability measurements from IM-MS and MS-IM-MS. The approach described here to isolate ions of membrane protein complexes will be useful for other MS methods, such as surface induced dissociation or collision induced dissociation to determine the stoichiometry of hetero-oligomeric membrane protein complexes.

  4. Differential Stiffness and Lipid Mobility in the Leaflets of Purple Membranes

    PubMed Central

    Voïtchovsky, Kislon; Antoranz Contera, Sonia; Kamihira, Miya; Watts, Anthony; Ryan, J. F.

    2006-01-01

    Purple membranes (PM) are two-dimensional crystals formed by bacteriorhodopsin and a variety of lipids. The lipid composition and density in the cytoplasmic (CP) leaflet differ from those of the extracellular (EC) leaflet. A new way of differentiating the two sides of such asymmetric membranes using the phase signal in alternate contact atomic force microscopy is presented. This method does not require molecular resolution and is applied to study the stiffness and intertrimer lipid mobility in both leaflets of the PM independently over a broad range of pH and salt concentrations. PM stiffens with increasing salt concentration according to two different regimes. At low salt concentration, the membrane Young's normal modulus grows quickly but differentially for the EC and CP leaflets. At higher salt concentration, both leaflets behave similarly and their stiffness converges toward the native environment value. Changes in pH do not affect PM stiffness; however, the crystal assembly is less pronounced at pH ≥ 10. Lipid mobility is high in the CP leaflet, especially at low salt concentration, but negligible in the EC leaflet regardless of pH or salt concentration. An independent lipid mobility study by solid-state NMR confirms and quantifies the atomic force microscopy qualitative observations. PMID:16387758

  5. Rapid Mobilization of Membrane Lipids in Wheat Leaf-Sheaths during Incompatible Interactions with Hessian Fly*

    PubMed Central

    Zhu, Lieceng; Liu, Xuming; Wang, Haiyan; Khajuria, Chitvan; Reese, John C.; Whitworth, R. Jeff; Welti, Ruth; Chen, Ming-Shun

    2013-01-01

    Hessian fly (HF) is a biotrophic insect that interacts with wheat on a gene-for-gene basis. We profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing the resistance gene H13. Our results revealed a 32 to 45% reduction in total concentrations of 129 lipid species in resistant plants during incompatible interactions within 24 h after HF attack. A smaller and delayed response was observed in susceptible plants during compatible interactions. Microarray and real-time PCR analyses of 168 lipid-metabolism related transcripts revealed that the abundance of many of these transcripts increased rapidly in resistant plants after HF attack, but did not change in susceptible plants. In association with the rapid mobilization of membrane lipids, the concentrations of some fatty acids and 12-oxo-phytodienoic acid (OPDA) increased specifically in resistant plants. Exogenous application of OPDA increased mortality of HF larvae significantly. Collectively, our data, along with previously published results, indicate that the lipids were mobilized through lipolysis, producing free fatty acids, which were likely further converted into oxylipins and other defense molecules. Our results suggest that rapid mobilization of membrane lipids constitutes an important step for wheat to defend against HF attack. PMID:22668001

  6. Factors Affecting Loss of Tympanic Membrane Mobility in Acute Otitis Media Model of Chinchilla

    PubMed Central

    Guan, Xiying; Chen, Yongzheng; Gan, Rong Z.

    2014-01-01

    Recently we reported that middle ear pressure (MEP), middle ear effusion (MEE), and ossicular changes each contribute to the loss of tympanic membrane (TM) mobility in a guinea pig model of acute otitis media (AOM) induced by S. pneumoniae (Guan and Gan, 2013). However, it is not clear how those factors vary along the course of the disease and whether those effects are reproducible in different species. In this study, a chinchilla AOM model was produced by transbullar injection of Haemophilus influenzae. Mobility of the TM at the umbo was measured by laser vibrometry in two treatment groups: 4 days (4D) and 8 days (8D) post inoculation. These time points represent relatively early and later phases of AOM. In each group, the vibration of the umbo was measured at three experimental stages: unopened, pressure-released, and effusion-removed ears. The effects of MEP and MEE and middle ear structural changes were quantified in each group by comparing the TM mobility at one stage with that of the previous stage. Our findings show that the factors affecting TM mobility do change with the disease time course. The MEP was the dominant contributor to reduction of TM mobility in 4D AOM ears, but showed little effect in 8D ears when MEE filled the tympanic cavity. MEE was the primary factor affecting TM mobility loss in 8D ears, but affected the 4D ears only at high frequencies. After the release of MEP and removal of MEE, residual loss of TM mobility was seen mainly at low frequencies in both 4D and 8D ears, and was associated with middle ear structural changes. Our findings establish that the factors contributing to TM mobility loss in the chinchilla ear were similar to those we reported previously for the guinea pig ears with AOM. Outcomes did not appear to differ between the two major bacterial species causing AOM in these animal models. PMID:24406734

  7. Membrane-Extraction Ion Mobility Spectrometry for In-Situ Detection of Chlorinated Hydrocarbons in Water

    SciTech Connect

    Du, Yongzhai; Zhang, Wei; Whitten, William B; Li, Haiyang; Watson, David B; Xu, Jun

    2010-01-01

    Membrane-extraction ion mobility spectrometry (ME-IMS) has been developed for in-situ sampling and analysis of trace chlorinated hydrocarbons in water in a single procedure. The sampling is configured so that aqueous contaminants permeate through a spiral hollow polydimethylsiloxane (PDMS) membrane and are carried away by a vapor flow through the membrane tube. The extracted analyte flows into an atmospheric pressure chemical ionization (APCI) chamber and is analyzed in a home-made IMS analyzer. PDMS membrane is found to effectively extract chlorinated hydrocarbon solvents from liquid phase to vapor. The specialized IMS analyzer has been found to have resolutions of R=33 and 41, respectively, for negative- and positive-modes and is capable of detecting aqueous tetrachloroethylene (PCE) and trichloroethylene (TCE) as low as 80 g/L and 74 g/L in negative ion mode, respectively. The time-dependent characteristics of sampling and detection of TCE are both experimentally and theoretically studied for various concentrations, membrane lengths, and flow rates. These characteristics demonstrate that membrane-extraction IMS is feasible for the continuous monitoring of chlorinated hydrocarbons in water.

  8. Transport Modeling of Membrane Extraction of Chlorinated Hydrocarbon from Water for Ion Mobility Spectrometry

    SciTech Connect

    Zhang, Wei; Du, Yongzhai; Feng, Zhili; Xu, Jun

    2010-01-01

    Membrane-extraction Ion Mobility Spectrometry (ME-IMS) is a feasible technique for the continuous monitoring of chlorinated hydrocarbons in water. This work studies theoretically the time-dependent characteristics of sampling and detection of trichloroethylene (TCE). The sampling is configured so that aqueous contaminants permeate through a hollow polydimethylsiloxane (PDMS) membrane and are carried away by a transport gas flowing through the membrane tube into IMS analyzer. The theoretical study is based on a two-dimensional transient fluid flow and mass transport model. The model describes the TCE mixing in the water, permeation through the membrane layer, and convective diffusion in the air flow inside membrane tube. The effect of various transport gas flow rates on temporal profiles of IMS signal intensity is investigated. The results show that fast time response and high transport yield can be achieved for ME-IMS by controlling the flow rate in the extraction membrane tube. These modeled time-response profiles are important for determining duty cycles of field-deployable sensors for monitoring chlorinated hydrocarbons in water.

  9. Corrections to the Saffman-Delbrück Mobility for Membrane Bound Proteins

    PubMed Central

    Naji, Ali; Levine, Alex J.; Pincus, P. A.

    2007-01-01

    Recent experiments (Gambin, Y., R. Lopez-Esparza, M. Reffay, E. Sierecki, N. S. Gov, M. Genest, R. S. Hodes, and W. Urbach. 2006. Proc. Natl. Acad. Sci. USA. 103:2098–2102) have called into question the applicability of the Saffman-Delbrück diffusivity for proteins embedded in the lipid bilayers. We present a simple argument to account for this observation that should be generically valid for a large class of transmembrane and membrane bound proteins. Whenever the protein-lipid interactions locally deform the membrane, that deformation generates new hydrodynamic stresses on the protein-membrane complex leading to a suppression of its mobility. We show that this suppression depends on the protein size in a manner consistent with the work of Gambin et al. PMID:17872958

  10. Mobility of water and selected atoms in DMPG lipid bilayer membranes

    NASA Astrophysics Data System (ADS)

    Hansen, F. Y.; Roennest, A.; Peters, G. H.; Taub, H.; Miskowiec, A.

    2013-03-01

    Molecular dynamics simulations have been used to study the structure and mobility of water and selected atoms in dimyristoyl-phosphoglycerol (DMPG) lipids forming a fully hydrated free standing bilayer membrane at 310 K. The effect of the anionic headgroup in DMPG on structure and dynamics has been studied by comparison with simulation[2] and experimental[3] results for bilayer membranes of dimyristoyl-phosphorylcholine (DMPC) lipids, which have a neutral head group and the same aliphatic tails. The membrane is found to be in the fluid phase with monovalent sodium counter ions and in the gel phase with divalent calcium counter ions as evidenced by an area/lipid change and the NMR order parameter. The simulation results are compared with preliminary neutron scattering results. Supported by NSF Grant No. DGE-1069091

  11. Corrections to the Saffman-Delbruck mobility for membrane bound proteins.

    PubMed

    Naji, Ali; Levine, Alex J; Pincus, P A

    2007-12-01

    Recent experiments (Gambin, Y., R. Lopez-Esparza, M. Reffay, E. Sierecki, N. S. Gov, M. Genest, R. S. Hodes, and W. Urbach. 2006. Proc. Natl. Acad. Sci. USA. 103:2098-2102) have called into question the applicability of the Saffman-Delbrück diffusivity for proteins embedded in the lipid bilayers. We present a simple argument to account for this observation that should be generically valid for a large class of transmembrane and membrane bound proteins. Whenever the protein-lipid interactions locally deform the membrane, that deformation generates new hydrodynamic stresses on the protein-membrane complex leading to a suppression of its mobility. We show that this suppression depends on the protein size in a manner consistent with the work of Gambin et al.

  12. Preserved transmembrane protein mobility in polymer-supported lipid bilayers derived from cell membranes.

    PubMed

    Pace, Hudson; Simonsson Nyström, Lisa; Gunnarsson, Anders; Eck, Elizabeth; Monson, Christopher; Geschwindner, Stefan; Snijder, Arjan; Höök, Fredrik

    2015-09-15

    Supported lipid bilayers (SLBs) have contributed invaluable information about the physiochemical properties of cell membranes, but their compositional simplicity often limits the level of knowledge that can be gained about the structure and function of transmembrane proteins in their native environment. Herein, we demonstrate a generic protocol for producing polymer-supported lipid bilayers on glass surfaces that contain essentially all naturally occurring cell-membrane components of a cell line while still retaining transmembrane protein mobility and activity. This was achieved by merging vesicles made from synthetic lipids (PEGylated lipids and POPC lipids) with native cell-membrane vesicles to generate hybrid vesicles which readily rupture into a continuous polymer-supported lipid bilayer. To investigate the properties of these complex hybrid SLBs and particularly the behavior of their integral membrane-proteins, we used total internal reflection fluorescence imaging to study a transmembrane protease, β-secretase 1 (BACE1), whose ectoplasmic and cytoplasmic domains could both be specifically targeted with fluorescent reporters. By selectively probing the two different orientations of BACE1 in the resulting hybrid SLBs, the role of the PEG-cushion on transmembrane protein lateral mobility was investigated. The results reveal the necessity of having the PEGylated lipids present during vesicle adsorption to prevent immobilization of transmembrane proteins with protruding domains. The proteolytic activity of BACE1 was unadulterated by the sonication process used to merge the synthetic and native membrane vesicles; importantly it was also conserved in the SLB. The presented strategy could thus serve both fundamental studies of membrane biophysics and the production of surface-based bioanalytical sensor platforms.

  13. Regional differences in the lateral mobility of plasma membrane lipids in a molluscan embryo.

    PubMed

    Speksnijder, J E; Dohmen, M R; Tertoolen, L G; de Laat, S W

    1985-07-01

    Regional and temporal differences in plasma membrane lipid mobility have been analyzed during the first three cleavage cycles of the embryo of the polar-lobe-forming mollusc Nassarius reticulatus by the fluorescence photobleaching recovery (FPR) method, using 1,1'-ditetradecyl 3,3,3',3'-tetramethylindocarbocyanine iodide (C14diI) as a fluorescent lipid probe. During this period of development the lateral diffusion coefficient of membrane lipids is consistently greater in the vegetal polar lobe area as compared to the animal plasma membrane area (on average 30%), demonstrating the existence of an animal-vegetal polarity in plasma membrane properties. At third cleavage, the differences between animal and vegetal plasma membrane region become even more pronounced; in the four animal micromeres the diffusion coefficient (D) and mobile fraction (MF) are 2.9 +/- 0.2 X 10(-9) cm2/sec and 51 +/- 2%, respectively, while in the four vegetal macromeres D = 5.0 +/- 0.3 X 10(-9) cm2/sec and MF = 78 +/- 2%. Superimposed upon the observed animal-vegetal polarity, the lateral diffusion in the polar lobe membrane area shows a cell-cycle-dependent modulation. The highest mean values for D are reached during the S phase (ranging from 7.0 to 7.8 X 10(-9) cm2/sec in the three cycles measured), while at the end of G2 phase and during early mitosis mean values for D have decreased significantly (ranging from 5.0 to 5.9 X 10(-9) cm2/sec). Diffusion rates in the animal membranes of the embryo are constant during the three successive cell cycles (D = 4.3-5.0 X 10(-9) cm2/sec), except for a peak at the S phase of the first cell cycle (D = 6.0 X 10(-9) cm2/sec). These results are discussed in relation with previously observed ultrastructural heterogeneities in the Nassarius egg plasma membrane. It is speculated that the observed animal-vegetal polarity in the organization of the egg membrane might play an important role in the process of cell diversification during early development.

  14. Determination of fuel ethers in water by membrane extraction ion mobility spectrometry.

    PubMed

    Holopainen, Sanna; Nousiainen, Marjaana; Sillanpää, Mika

    2013-03-15

    Fuel oxygenates are environmentally detrimental compounds due to their rapid migration to groundwater. Fuel oxygenates have been reported to cause taste and odour problems in drinking water, and they also have long-term health effects. Feasible analytical methods are required to observe the presence of fuel oxygenates in drinking and natural water. The authors studied ion mobility spectrometry (IMS) to determinate isomeric fuel ether oxygenates; ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME), separated from aqueous matrices with a pervaporation membrane module. Methyl tert-butyl ether (MTBE) was also membrane extracted and detected with IMS. The authors demonstrated that fuel ethers (MTBE, ETBE, DIPE, and TAME) can be quantified at μg/L level with membrane extraction IMS. A membrane extraction module coupled to IMS is a time and cost effective analysis method because sampling can be performed in a single procedure and from different natural water matrices within a few minutes. Consequently, IMS combined with membrane extraction is suitable not only for waterworks and other online applications but also in the field monitoring the quality of drinking and natural water.

  15. Imaging of mobile long-lived nanoplatforms in the live cell plasma membrane.

    PubMed

    Brameshuber, Mario; Weghuber, Julian; Ruprecht, Verena; Gombos, Imre; Horváth, Ibolya; Vigh, László; Eckerstorfer, Paul; Kiss, Endre; Stockinger, Hannes; Schütz, Gerhard J

    2010-12-31

    The plasma membrane has been hypothesized to contain nanoscopic lipid platforms, which are discussed in the context of "lipid rafts" or "membrane rafts." Based on biochemical and cell biological studies, rafts are believed to play a crucial role in many signaling processes. However, there is currently not much information on their size, shape, stability, surface density, composition, and heterogeneity. We present here a method that allows for the first time the direct imaging of nanoscopic long-lived platforms with raft-like properties diffusing in the live cell plasma membrane. Our method senses these platforms by their property to assemble a characteristic set of fluorescent marker proteins or lipids on a time scale of seconds. A special photobleaching protocol was used to reduce the surface density of labeled mobile platforms down to the level of well isolated diffraction-limited spots without altering the single spot brightness. The statistical distribution of probe molecules per platform was determined by single molecule brightness analysis. For demonstration, we used the consensus raft marker glycosylphosphatidylinositol-anchored monomeric GFP and the fluorescent lipid analog BODIPY-G(M1), which preferentially partitions into liquid-ordered phases. For both markers, we found cholesterol-dependent homo-association in the plasma membrane of living CHO and Jurkat T cells in the resting state, thereby demonstrating the existence of small, mobile, long-lived platforms containing these probes. We further applied the technology to address structural changes in the plasma membrane during fever-type heat shock: at elevated temperatures, the glycosylphosphatidylinositol-anchored monomeric GFP homo-association disappeared, accompanied by an increase in the expression of the small heat shock protein Hsp27.

  16. Factors affecting loss of tympanic membrane mobility in acute otitis media model of chinchilla.

    PubMed

    Guan, Xiying; Chen, Yongzheng; Gan, Rong Z

    2014-03-01

    Recently we reported that middle ear pressure (MEP), middle ear effusion (MEE), and ossicular changes each contribute to the loss of tympanic membrane (TM) mobility in a guinea pig model of acute otitis media (AOM) induced by Streptococcus pneumoniae (Guan and Gan, 2013). However, it is not clear how those factors vary along the course of the disease and whether those effects are reproducible in different species. In this study, a chinchilla AOM model was produced by transbullar injection of Haemophilus influenzae. Mobility of the TM at the umbo was measured by laser vibrometry in two treatment groups: 4 days (4D) and 8 days (8D) post inoculation. These time points represent relatively early and later phases of AOM. In each group, the vibration of the umbo was measured at three experimental stages: unopened, pressure-released, and effusion-removed ears. The effects of MEP and MEE and middle ear structural changes were quantified in each group by comparing the TM mobility at one stage with that of the previous stage. Our findings show that the factors affecting TM mobility do change with the disease time course. The MEP was the dominant contributor to reduction of TM mobility in 4D AOM ears, but showed little effect in 8D ears when MEE filled the tympanic cavity. MEE was the primary factor affecting TM mobility loss in 8D ears, but affected the 4D ears only at high frequencies. After the release of MEP and removal of MEE, residual loss of TM mobility was seen mainly at low frequencies in both 4D and 8D ears, and was associated with middle ear structural changes. Our findings establish that the factors contributing to TM mobility loss in the chinchilla ear were similar to those we reported previously for the guinea pig ears with AOM. Outcomes did not appear to differ between the two major bacterial species causing AOM in these animal models. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Aqueous-filled polymer microcavity arrays: versatile & stable lipid bilayer platforms offering high lateral mobility to incorporated membrane proteins.

    PubMed

    Basit, Hajra; Gaul, Vinnie; Maher, Sean; Forster, Robert J; Keyes, Tia E

    2015-05-07

    A key prerequisite in an ideal supported lipid bilayer based cell membrane model is that the mobility of both the lipid matrix and its components are unhindered by the underlying support. This is not trivial and with the exception of liposomes, many of even the most advanced approaches, although accomplishing lipid mobility, fail to achieve complete mobility of incorporated membrane proteins. This is addressed in a novel platform comprising lipid bilayers assembled over buffer-filled, arrays of spherical cap microcavities formed from microsphere template polydimethoxysilane. Prior to bilayer assembly the PDMS is rendered hydrophilic by plasma treatment and the lipid bilayer prepared using Langmuir Blodgett assembly followed by liposome/proteoliposome fusion. Fluorescence Lifetime Correlation Spectroscopy confirmed the pore suspended lipid bilayer exhibits diffusion coefficients comparable to free-standing vesicles in solution. The bilayer modified arrays are highly reproducible and stable over days. As the bilayers are suspended over deep aqueous reservoirs, reconstituted membrane proteins experience an aqueous interface at both membrane interfaces and attain full lateral mobility. Their utility as membrane protein platforms was exemplified in two case studies with proteins of different dimensions in their extracellular and cytoplasmic domains reconstituted into DOPC lipid bilayers; Glycophorin A, and Integrin αIIbβ3. In both cases, the proteins exhibited 100% mobility with high lateral diffusion coefficients.

  18. Feasibility and Safety of Early Physical Therapy and Active Mobilization for Patients on Extracorporeal Membrane Oxygenation.

    PubMed

    Ko, YoungJun; Cho, Yang Hyun; Park, Yun Hee; Lee, Hyun; Suh, Gee Young; Yang, Jeong Hoon; Park, Chi-Min; Jeon, Kyeongman; Chung, Chi Ryang

    2015-01-01

    Physical therapy (PT) and early mobilization for critically ill patients have been popularized to decrease the length of hospital stay and to improve the quality of life after discharge. We reviewed our experience of PT and active mobilization for patients on extracorporeal membrane oxygenation (ECMO) in terms of its technical feasibility and safety. Study endpoints were safety events during PT and PT interruptions due to unstable vital signs. Of the eight patients, one patient (12.5%) had venoarterial ECMO, seven patients (87.5%) had venovenous ECMO. Among total of 62 sessions including 31 sessions (50%) of passive range of motion and electrical muscle stimulation, 17 sessions (27.4%) were performed for patients who were sitting in bed or on the edge of bed, two sessions (3.2%) were for strengthening in sitting, 11 sessions (18%) were for standing or marching in place, one session (2%) was for walking. Eight sessions (13%) of sitting were supported with invasive mechanical ventilation. Three sessions (5%) were stopped due to tachycardia (n = 1) and tachypnea (n = 2). There was no clinically significant adverse event in patients. Thus, early PT and mobilization for patients on ECMO might be feasible and safe at an experienced ECMO center.

  19. A nanoscale soft-ionization membrane: A novel ionizer for ion mobility spectrometers for space applications

    NASA Astrophysics Data System (ADS)

    Hartley, Frank T.; Kanik, Isik

    2002-11-01

    The Jet Propulsion Laboratory (JPL) has developed a novel nanometer-thick "Soft Ionization Membrane" (SIM) which is capable of ionizing nearly 100% of the gases that pass through it. Both sides of the membrane are coated with a metallic conducting film. A modest potential of less than 10 Volts across the membrane produces an electric field in excess of 107 V/cm over a region that is smaller than the mean free path of gas molecules which ionizes the neutral molecules that passing through. Because the region of high electric field is smaller than the mean free path of gas molecules, there are virtually no high energy collisions and the system does not suffer from the fatal problem of avalanche breakdown. The soft ionization mechanism does not fracture the medium or cause any secondary ionization. Thus, a truly new ionization technique is enabled by a simple nanoscale micromachined device. The SIM is tiny, rugged and well suited for a wide variety of applications ranging from space micropropulsion systems to miniature analytical separation devices. In this paper we focus our attention on ion mobility spectrometers (IMSs) as a potential candidate to be incorporated with SIM.

  20. Effect of integral membrane proteins on the lateral mobility of plastoquinone in phosphatidylcholine proteoliposomes

    PubMed Central

    Blackwell, Mary F.; Whitmarsh, John

    1990-01-01

    Pyrene fluorescence quenching by plastoquinone was used to estimate the rate of plastoquinone lateral diffusion in soybean phosphatidylcholine proteoliposomes containing the following integral membrane proteins: gramicidin D, spinach cytochrome bf complex, spinach cytochrome f, reaction centers from Rhodobacter sphaeroides, beef heart mitochondrial cytochrome bc1, and beef heart mitochondrial cytochrome oxidase. The measured plastoquinone lateral diffusion coefficient varied between 1 and 3 · 10-7 cm2 s-1 in control liposomes that lacked protein. When proteins were added, these values decreased: a 10-fold decrease was observed when 16-26% of the membrane surface area was occupied by protein for all the proteins but gramicidin. The larger protein complexes (cytochrome bf, Rhodobacter sphaeroides reaction centers, cytochrome bc1, and cytochrome oxidase), whose hydrophobic volumes were 15-20 times as large as that of cytochrome f and the gramicidin transmembrane dimer, were 15-20 times as effective in decreasing the lateral-diffusion coefficient over the range of concentrations studied. These proteins had a much stronger effect than that observed for bacteriorhodopsin in fluorescence photobleaching recovery measurements. The effect of high-protein concentrations in gramicidin proteoliposomes was in close agreement with fluorescence photobleaching measurements. The results are compared with the predictions of several theoretical models of lateral mobility as a function of integral membrane concentration. PMID:19431774

  1. Differential mobility of pigment-protein complexes in granal and agranal thylakoid membranes of C₃ and C₄ plants.

    PubMed

    Kirchhoff, Helmut; Sharpe, Richard M; Herbstova, Miroslava; Yarbrough, Robert; Edwards, Gerald E

    2013-01-01

    The photosynthetic performance of plants is crucially dependent on the mobility of the molecular complexes that catalyze the conversion of sunlight to metabolic energy equivalents in the thylakoid membrane network inside chloroplasts. The role of the extensive folding of thylakoid membranes leading to structural differentiation into stacked grana regions and unstacked stroma lamellae for diffusion-based processes of the photosynthetic machinery is poorly understood. This study examines, to our knowledge for the first time, the mobility of photosynthetic pigment-protein complexes in unstacked thylakoid regions in the C₃ plant Arabidopsis (Arabidopsis thaliana) and agranal bundle sheath chloroplasts of the C₄ plants sorghum (Sorghum bicolor) and maize (Zea mays) by the fluorescence recovery after photobleaching technique. In unstacked thylakoid membranes, more than 50% of the protein complexes are mobile, whereas this number drops to about 20% in stacked grana regions. The higher molecular mobility in unstacked thylakoid regions is explained by a lower protein-packing density compared with stacked grana regions. It is postulated that thylakoid membrane stacking to form grana leads to protein crowding that impedes lateral diffusion processes but is required for efficient light harvesting of the modularly organized photosystem II and its light-harvesting antenna system. In contrast, the arrangement of the photosystem I light-harvesting complex I in separate units in unstacked thylakoid membranes does not require dense protein packing, which is advantageous for protein diffusion.

  2. Reduction in lateral lipid mobility of lipid bilayer membrane by atmospheric pressure plasma irradiation

    NASA Astrophysics Data System (ADS)

    Suda, Yoshiyuki; Tero, Ryugo; Yamashita, Ryuma; Yusa, Kota; Takikawa, Hirofumi

    2016-03-01

    Plasma medicine is an emerging research field in which various applications of electrical discharge, especially in the form of nonequilibrium plasma at atmospheric pressure, are examined, for example, the application of plasma to biological targets for various purposes such as selective killing of tumor cells and blood stanching. We have focused on the behavior of an artificial cell membrane system at the solid-liquid interface. To evaluate the lateral lipid mobility, we measured the diffusion coefficient of the supported lipid bilayer (SLB) composed of dioleoylphosphatidylcholine with fluorescence recovery after photobleaching by confocal laser scanning microscopy. It was found that the diffusion coefficient was decreased by plasma irradiation and that the diffusion coefficient decreasing rate proceeded with increasing plasma power. We investigated the effects of stimulation with an equilibrium chemical, H2O2, on the SLB and confirmed that the diffusion coefficient did not change at least up to a H2O2 concentration of 5 mM. These results indicate that transient active species generated by plasma play critical roles in the reduction in SLB fluidity. The effects of the two generated major oxidized lipid species, hydroxyl- or hydroperoxy-phosphatidylcholine (PC) and acyl-chain-truncated PCs terminated with aldehyde or carboxyl group, on lateral lipid mobility are discussed.

  3. Location and mobility of twin arginine translocase subunits in the Escherichia coli plasma membrane.

    PubMed

    Ray, Nicola; Nenninger, Anja; Mullineaux, Conrad W; Robinson, Colin

    2005-05-06

    The twin arginine translocation (Tat) system transports folded proteins across the bacterial plasma membrane. Two primary Tat complexes have been identified, comprising TatABC or TatA multimers, which may interact at the point of translocation. We have analyzed green/cyan/yellow fluorescent protein (XFP) fusions to each of the Tat subunits. We show that the TatB and TatC fusions are active and incorporated into purified TatABC complexes. Proteolytic clipping of the TatA-XFP fusion precludes a definitive conclusion regarding activity, but we do find that the full fusion protein is preferentially incorporated into the TatABC complex. A previous study has proposed that TatB and possibly TatC are localized at the cell poles, whereas TatA is distributed more uniformly throughout the plasma membrane. Here, we likewise show that TatA-XFP is primarily distributed around the periphery of the cell. However, whereas much of the TatB-XFP is found at the poles, quantitative imaging studies show that approximately half of the protein is uniformly distributed in the plasma membrane. Moreover, we show that the bulk of TatC-XFP is detected as a halo around the cells, in some cases as punctate areas that are much smaller than those occupied by TatB-green fluorescent protein (GFP), indicating a uniform distribution. No evidence for a polar localization of TatC-GFP was obtained. Although TatC-GFP is found correctly complexed with TatB, a high proportion of TatB-GFP is not linked to TatC, and we propose that this "free" TatB forms unphysiological assemblies, possibly because it is synthesized in excess. Since TatC is invariably complexed with TatB in wild-type complexes, the combined data demonstrate that TatABC complexes are uniformly distributed throughout the plasma membrane. The significance of the punctate TatA/B/C-GFP is unclear; fluorescence recovery after photobleaching measurements show that these pools of proteins are immobile, whereas nonaggregated proteins are highly mobile

  4. Visualizing the mobility and distribution of chlorophyll proteins in higher plant thylakoid membranes: effects of photoinhibition and protein phosphorylation.

    PubMed

    Goral, Tomasz K; Johnson, Matthew P; Brain, Anthony P R; Kirchhoff, Helmut; Ruban, Alexander V; Mullineaux, Conrad W

    2010-06-01

    The diffusion of proteins in chloroplast thylakoid membranes is believed to be important for processes including the photosystem-II repair cycle and the regulation of light harvesting. However, to date there is very little direct information on the mobility of thylakoid proteins. We have used fluorescence recovery after photobleaching in a laser-scanning confocal microscope to visualize in real time the exchange of chlorophyll proteins between grana in intact spinach (Spinacia oleracea L.) and Arabidopsis chloroplasts. Most chlorophyll proteins in the grana appear immobile on the 10-min timescale of our measurements. However, a limited population of chlorophyll proteins (accounting for around 15% of chlorophyll fluorescence) can exchange between grana on this timescale. In intact, wild-type chloroplasts this mobile population increases significantly after photoinhibition, consistent with a role for protein diffusion in the photosystem-II repair cycle. No such increase in mobility is seen in isolated grana membranes, or in the Arabidopsis stn8 and stn7 stn8 mutants, which lack the protein kinases required for phosphorylation of photosystem II core proteins and light-harvesting complexes. Furthermore, mobility under low-light conditions is significantly lower in stn8 and stn7 stn8 plants than in wild-type Arabidopsis. The changes in protein mobility correlate with changes in the packing density and size of thylakoid protein complexes, as observed by freeze-fracture electron microscopy. We conclude that protein phosphorylation switches the membrane system to a more fluid state, thus facilitating the photosystem-II repair cycle.

  5. Interaction of caldesmon with endoplasmic reticulum membrane: effects on the mobility of phospholipids in the membrane and on the phosphatidylserine base-exchange reaction.

    PubMed Central

    Makowski, P; Makuch, R; Sikorski, A F; Jezierski, A; Pikula, S; Dabrowska, R

    1997-01-01

    We have previously demonstrated by tryptophan fluorescence the interaction of caldesmon with anionic phospholipid vesicles [Czurylo, Zborowski and Dabrowska (1993) Biochem. J. 291, 403-408]. In the present work we investigated the interaction of caldesmon with natural-membrane (rat liver endoplasmic reticulum) phospholipids by co-sedimentation assay. The results indicate that 1 mol of caldesmon binds approx. 170 mol of membrane phospholipids with a binding affinity constant of 7.3 x 10(6) M-1. The caldesmon-membrane phospholipid complex dissociates with increasing salt concentration and in the presence of Ca2+/calmodulin. As indicated by EPR measurements of membrane lipids labelled with 5-doxyl stearate and TEMPO-phosphatidylethanolamine, binding of caldesmon results in an increase in mobility of the acyl chains (in the region of carbon 5) and a decrease in polar headgroup mobility of phospholipids. Interaction of caldesmon with phospholipids is accompanied by inhibition of phosphatidylethanolamine synthesis via a phospholipid base-exchange reaction, with phosphatidylserine as substrate. This shows that, of the endoplasmic reticulum membrane phospholipids, the main target of caldesmon is phosphatidylserine. PMID:9371708

  6. Imitation of artificial membrane system via mobile phases with Tween-80 and cholic acid in biopartitioning micellar chromatography.

    PubMed

    Rukhadze, Marina D; Sebiskveradze, Maya V; Akhalkatsi, Tsaro G; Makharadze, Teona G

    2006-08-01

    The chromatographic behaviour of compounds of biomedical significance was studied using micellar mobile phases modified with polyoxyethylene (20) sorbitan monooleate (Tween-80). The influence of the surfactant within the 0.75-4% concentration range on the retention factor of model compounds was investigated. The biological surfactant cholic acid was introduced into the mobile phases in order to approach to the structure of natural membranes, viz. erythrocyte and cytoplasmatic membranes. It was found that curves of dependence of retention factor vs concentration of Tween-80 in the absence and presence of cholic acid in the mobile phase considerably diverge with one another, especially in the 2-3% concentration range of Tween-80 using C18-type support. Increasing the concentration of Tween-80 resulted in the increase of retention factors using phenyl-coated stationary phase.

  7. Mutual diffusion of inclusions in freely suspended smectic liquid crystal films.

    PubMed

    Qi, Zhiyuan; Nguyen, Zoom Hoang; Park, Cheol Soo; Glaser, Matthew A; Maclennan, Joseph E; Clark, Noel A; Kuriabova, Tatiana; Powers, Thomas R

    2014-09-19

    We study experimentally and theoretically the hydrodynamic interaction of pairs of circular inclusions in two-dimensional, fluid smectic membranes suspended in air. By analyzing their Brownian motion, we find that the radial mutual mobilities of identical inclusions are independent of their size but that the angular coupling becomes strongly size dependent when their radius exceeds a characteristic hydrodynamic length. These observations are described well for arbitrary inclusion separations by a model that generalizes the Levine-MacKintosh theory of point-force response functions and uses a boundary-element approach to calculate the mobility matrix for inclusions of finite extent.

  8. 47 CFR 90.165 - Procedures for mutually exclusive applications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Applications and Authorizations Special Rules... exclusive applications. Mutually exclusive commercial mobile radio service applications are processed in... 47 Telecommunication 5 2011-10-01 2011-10-01 false Procedures for mutually exclusive...

  9. 47 CFR 90.165 - Procedures for mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Applications and Authorizations Special Rules... exclusive applications. Mutually exclusive commercial mobile radio service applications are processed in... 47 Telecommunication 5 2010-10-01 2010-10-01 false Procedures for mutually exclusive applications...

  10. Mobile ER-to-Golgi but not post-Golgi membrane transport carriers disappear during the terminal myogenic differentiation.

    PubMed

    Nevalainen, Mika; Kaisto, Tuula; Metsikkö, Kalervo

    2010-10-01

    The organelles of the exocytic pathway undergo a profound reorganization during the myogenic differentiation. Here, we have investigated the dynamics of the membrane trafficking at various stages of the differentiation process by using the green fluorescent protein-tagged, temperature-sensitive vesicular stomatitis virus G protein (tsG-GFP) as a marker. At the restrictive temperature of 39°C, the tsG-GFP located to the endoplasmic reticulum (ER) at each stage of differentiation. Mobile membrane containers moving from the ER to the Golgi elements were seen in myoblasts and myotubes upon shifting the temperature to 20°C. In adult myofibers, in contrast, such containers were not seen although the tsG-GFP rapidly shifted from the ER to the Golgi elements. The mobility of tsG-GFP in the myofiber ER was restricted, suggesting localization in an ER sub-compartment. Contrasting with the ER-to-Golgi trafficking, transport from the Golgi elements to the plasma membrane involved mobile transport containers in all differentiation stages. These findings indicate that ER-to-Golgi trafficking in adult skeletal myofibers does not involve long-distance moving membrane carriers as occurs in other mammalian cell types.

  11. Capabilities of a mobile extracorporeal membrane oxygenation service for severe respiratory failure delivered by intensive care specialists.

    PubMed

    Sherren, P B; Shepherd, S J; Glover, G W; Meadows, C I S; Langrish, C; Ioannou, N; Wyncoll, D; Daly, K; Gooby, N; Agnew, N; Barrett, N A

    2015-06-01

    We conducted a single-centre observational study of retrievals for severe respiratory failure over 12 months. Our intensivist-delivered retrieval service has mobile extracorporeal membrane oxygenation capabilities. Sixty patients were analysed: 34 (57%) were female and the mean (SD) age was 44.1 (13.6) years. The mean (SD) PaO2 /FI O2 ratio at referral was 10.2 (4.1) kPa and median (IQR [range]) Murray score was 3.25 (3.0-3.5 [1.5-4.0]). Forty-eight patients (80%) required veno-venous extracorporeal membrane oxygenation at the referring centre. There were no cannulation or extracorporeal membrane oxygenation-related complications. The median (IQR [range]) retrieval distance was 47.2 (14.9-77.0 [2.3-342.0]) miles. There were no major adverse events during retrieval. Thirty-seven patients (77%) who received extracorporeal membrane oxygenation survived to discharge from the intensive care unit and 36 patients (75%) were alive after six months. Senior intensivist-initiated and delivered mobile extracorporeal membrane oxygenation is safe and associated with a high incidence of survival.

  12. Spacesuit Water Membrane Evaporator Integration with the ISS Extravehicular Mobility Unit

    NASA Technical Reports Server (NTRS)

    Margiott, Victoria; Boyle, Robert

    2014-01-01

    NASA has developed a Solid Water Membrane Evaporation (SWME) to provide cooling for the next generation spacesuit. The current spacesuit team has looked at this technology from the standpoint of using the ISS EMU to demonstrate the SWME technology while EVA, and from the standpoint of augmenting EMU cooling in the case of a fouled EMU cooling system. One approach to increasing the TRL of the system is to incorporate this hardware with the existing EMU. Several integration issues were addressed to support a potential demonstration of the SWME with the existing EMU. Systems analysis was performed to assess the capability of the SWME to maintain crewmember cooling and comfort as a replacement for sublimation. The materials of the SWME were reviewed to address compatibility with the EMU. Conceptual system placement and integration with the EMU via an EVA umbilical system to ensure crew mobility and Airlock egress were performed. A concept of operation for EVA use was identified that is compatible with the existing system. This concept is extensible as a means to provide cooling for the existing EMU. The cooling system of one of the EMUs on orbit has degraded, with the root cause undetermined. Should there be a common cause resident on ISS, this integration could provide a means to recover cooling capability for EMUs on orbit.

  13. On the mobility, membrane location and functionality of mechanosensitive channels in Escherichia coli.

    PubMed

    van den Berg, Jonas; Galbiati, Heloisa; Rasmussen, Akiko; Miller, Samantha; Poolman, Bert

    2016-09-06

    Bacterial mechanosensitive channels protect cells from structural damage during hypoosmotic shock. MscS, MscL and MscK are the most abundant channels in E. coli and arguably the most important ones in osmoprotection. By combining physiological assays with quantitative photo-activated localization microscopy (qPALM), we find an almost linear relationship between channel abundance and cell survival. A minimum of 100 MscL (or MscS) channels is needed for protection when a single type of channel is expressed. Under native-like conditions MscL, MscS as well as MscK distribute homogeneously over the cytoplasmic membrane and the lateral diffusion of the channels is in accordance with their relative protein mass. However, we observe cluster formation and a reduced mobility of MscL when the majority of the subunits of the pentameric channel contain the fluorescent mEos3.2 protein. These data provide new insights into the quantitative biology of mechanosensitive channels and emphasizes the need for care in analysing protein complexes even when the fluorescent tag has been optimized for monomeric behaviour.

  14. Voltage- and Tension-Dependent Lipid Mobility in the Outer Hair Cell Plasma Membrane

    NASA Astrophysics Data System (ADS)

    Oghalai, John S.; Zhao, Hong-Bo; Kutz, J. Walter; Brownell, William E.

    2000-01-01

    The mechanism responsible for electromotility of outer hair cells in the ear is unknown but is thought to reside within the plasma membrane. Lipid lateral diffusion in the outer hair cell plasma membrane is a sigmoidal function of transmembrane potential and bathing media osmolality. Cell depolarization or hyposmotic challenge shorten the cell and reduce membrane fluidity by half. Changing the membrane tension with amphipathic drugs results in similar reductions. These dynamic changes in membrane fluidity represent the modulation of membrane tension by lipid-protein interactions. The voltage dependence may be associated with the force-generating motors that contribute to the exquisite sensitivity of mammalian hearing.

  15. Analytical Investigation and Improvement of Performance of a Proton Exchange Membrane (Pem) Fuel Cell in Mobile Applications

    NASA Astrophysics Data System (ADS)

    Khazaee, I.

    2015-05-01

    In this study, the performance of a proton exchange membrane fuel cell in mobile applications is investigated analytically. At present the main use and advantages of fuel cells impact particularly strongly on mobile applications such as vehicles, mobile computers and mobile telephones. Some external parameters such as the cell temperature (Tcell ) , operating pressure of gases (P) and air stoichiometry (λair ) affect the performance and voltage losses in the PEM fuel cell. Because of the existence of many theoretical, empirical and semi-empirical models of the PEM fuel cell, it is necessary to compare the accuracy of these models. But theoretical models that are obtained from thermodynamic and electrochemical approach, are very exact but complex, so it would be easier to use the empirical and smi-empirical models in order to forecast the fuel cell system performance in many applications such as mobile applications. The main purpose of this study is to obtain the semi-empirical relation of a PEM fuel cell with the least voltage losses. Also, the results are compared with the existing experimental results in the literature and a good agreement is seen.

  16. The evolution of mutualism.

    PubMed

    Leigh, E G

    2010-12-01

    Like altruism, mutualism, cooperation between species, evolves only by enhancing all participants' inclusive fitness. Mutualism evolves most readily between members of different kingdoms, which pool complementary abilities for mutual benefit: some of these mutualisms represent major evolutionary innovations. Mutualism cannot persist if cheating annihilates its benefits. In long-term mutualisms, symbioses, at least one party associates with the other nearly all its life. Usually, a larger host harbours smaller symbionts. Cheating is restrained by vertical transmission, as in Buchnera; partner fidelity, as among bull-thorn acacias and protective ants; test-based choice of symbionts, as bobtail squid choose bioluminescent bacteria; or sanctioning nonperforming symbionts, as legumes punish nonperforming nitrogen-fixing bacteria. Mutualisms involving brief exchanges, as among plants and seed-dispersers, however, persist despite abundant cheating. Both symbioses and brief-exchange mutualisms have transformed whole ecosystems. These mutualisms may be steps towards ecosystems which, like Adam Smith's ideal economy, serve their members' common good. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

  17. Acid effect on 99mTc and 99Mo mutual separation and their transport across supported liquid membrane extraction system

    NASA Astrophysics Data System (ADS)

    Ashraf Chaudry, M.

    2000-02-01

    Work on 99mTc extraction using supported liquid membrane (SLM) has been performed with tri-n-octylamine as a carrier. MoO 4 2- ions transport with TOA-xylene has alos been studied with respect to HCl concentration (0.001 to 0.05M) in the feed solution. 99mTc transport in the same HCl concentration range has shown that while MoO 4 2- ions flux is higher at -5mol/m2.s, the TcO 4 - ions flux is in the range of (5-7)×10-11 mol/m2.s. In case of sulphuric acid in the feed the transport of 99mTc has been found to be higher ((28-55)×10-11 mol/m2), while 99Mo transport is observed to be suppressed as the H2SO4 concentration in the feed solution increases, providing a useful method for extraction of 99mTc, produced from the disintegration of 99Mo with time. Membranes supports used are of polypropylene and PTFE material. Effect of acid on Mo species present in the feed solution and the mechanism of transport through the SLM are also discussed.

  18. Proton detection for signal enhancement in solid-state NMR experiments on mobile species in membrane proteins.

    PubMed

    Ward, Meaghan E; Ritz, Emily; Ahmed, Mumdooh A M; Bamm, Vladimir V; Harauz, George; Brown, Leonid S; Ladizhansky, Vladimir

    2015-12-01

    Direct proton detection is becoming an increasingly popular method for enhancing sensitivity in solid-state nuclear magnetic resonance spectroscopy. Generally, these experiments require extensive deuteration of the protein, fast magic angle spinning (MAS), or a combination of both. Here, we implement direct proton detection to selectively observe the mobile entities in fully-protonated membrane proteins at moderate MAS frequencies. We demonstrate this method on two proteins that exhibit different motional regimes. Myelin basic protein is an intrinsically-disordered, peripherally membrane-associated protein that is highly flexible, whereas Anabaena sensory rhodopsin is composed of seven rigid transmembrane α-helices connected by mobile loop regions. In both cases, we observe narrow proton linewidths and, on average, a 10× increase in sensitivity in 2D insensitive nuclear enhancement of polarization transfer-based HSQC experiments when proton detection is compared to carbon detection. We further show that our proton-detected experiments can be easily extended to three dimensions and used to build complete amino acid systems, including sidechain protons, and obtain inter-residue correlations. Additionally, we detect signals which do not correspond to amino acids, but rather to lipids and/or carbohydrates which interact strongly with membrane proteins.

  19. Triglyceride Blisters in Lipid Bilayers: Implications for Lipid Droplet Biogenesis and the Mobile Lipid Signal in Cancer Cell Membranes

    PubMed Central

    Khandelia, Himanshu; Duelund, Lars; Pakkanen, Kirsi I.; Ipsen, John H.

    2010-01-01

    Triglycerides have a limited solubility, around 3%, in phosphatidylcholine lipid bilayers. Using millisecond-scale course grained molecular dynamics simulations, we show that the model lipid bilayer can accommodate a higher concentration of triolein (TO) than earlier anticipated, by sequestering triolein molecules to the bilayer center in the form of a disordered, isotropic, mobile neutral lipid aggregate, at least 17 nm in diameter, which forms spontaneously, and remains stable on at least the microsecond time scale. The results give credence to the hotly debated existence of mobile neutral lipid aggregates of unknown function present in malignant cells, and to the early biogenesis of lipid droplets accommodated between the two leaflets of the endoplasmic reticulum membrane. The TO aggregates give the bilayer a blister-like appearance, and will hinder the formation of multi-lamellar phases in model, and possibly living membranes. The blisters will result in anomalous membrane probe partitioning, which should be accounted for in the interpretation of probe-related measurements. PMID:20877640

  20. Development of a Low-Cost, Durable Membrane and Membrane Electrode Assemby for Stationary and Mobile Fuel Cell Applications

    SciTech Connect

    Michel Foure; Gaboury, Scott; Goldbach, Jim; Mountz, David; Yi, Jung

    2008-01-31

    The development of low cost, durable membranes and membranes electrode assemblies (MEAs) remain a critical challenge for the successful introduction of fuel cells into mass markets. It was the goal of the team lead by Arkema, Inc. (formerly Atofina, Inc.) to address these shortages. Thus, this project addresses the following technical barriers from the Fuel Cells section of the Hydrogen Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan: (A) Durability (B) Cost Arkema’s approach consisted in using blends of polyvinylidenefluoride (PVDF) and proprietary sulfonated polyelectrolytes. The strength and originality of Arkema’s approach lies in the decoupling of ion conductivity from the other requirements. Kynar® (Arkema trade name for PVDF) provides an exceptional combination of properties that make it ideally suited for a membrane matrix. In a first phase, Arkema demonstrated the feasibility of the concept with the M31 membrane generation. After MEA optimization, it was shown that the beginning-of-life (BOL) performance of M31 MEAs was essentially on a par with that of PFSA MEAs at 60ºC under fully humidified conditions. On the other hand, long-term durability studies showed a high decay rate of 45µV/h over a 2100 hr. test. Arkema then designed several families of polyelectrolyte candidates, which, in principle, could not undergo the same failure mechanisms. A new membrane candidate was developed: M41. It offered the same generally good mechanical, ex-situ conductivity and gas barrier properties as M31. In addition, ex-situ accelerated testing suggested a several orders of magnitude improvement in chemical stability. M41 based MEAs showed comparable BOL performance with that of PFSA (80ºC, 100% RH). M41 MEAs were further shown to be able to withstand several hours temperature excursions at 120ºC without apparent damage. Accelerated studies were carried out using the DOE and/or US Fuel Cell Council

  1. Membrane-based continuous remover of trifluoroacetic acid in mobile phase for LC-ESI-MS analysis of small molecules and proteins.

    PubMed

    Zhou, Zhigui; Zhang, Jialing; Xing, Jiawei; Bai, Yu; Liao, Yiping; Liu, Huwei

    2012-07-01

    We developed a "continuous" trifluoroacetic acid (TFA) remover based on electrodialysis with bipolar membrane for online coupling of liquid chromatography (LC) and electrospray ionization mass spectrometry (ESI-MS) using TFA containing mobile phase. With the TFA remover as an interface, the TFA anion in the mobile phase was removed based on electrodialysis mechanism, and meanwhile, the anion exchange membrane was self-regenerated by the hydroxide ions produced by the bipolar membrane. So the remover could continuously work without any additional regeneration process. The established LC-TFA remover-MS system has been successfully applied for the qualitative and quantitative analysis of small molecules as well as proteins.

  2. Membrane-Based Continuous Remover of Trifluoroacetic Acid in Mobile Phase for LC-ESI-MS Analysis of Small Molecules and Proteins

    NASA Astrophysics Data System (ADS)

    Zhou, Zhigui; Zhang, Jialing; Xing, Jiawei; Bai, Yu; Liao, Yiping; Liu, Huwei

    2012-07-01

    We developed a "continuous" trifluoroacetic acid (TFA) remover based on electrodialysis with bipolar membrane for online coupling of liquid chromatography (LC) and electrospray ionization mass spectrometry (ESI-MS) using TFA containing mobile phase. With the TFA remover as an interface, the TFA anion in the mobile phase was removed based on electrodialysis mechanism, and meanwhile, the anion exchange membrane was self-regenerated by the hydroxide ions produced by the bipolar membrane. So the remover could continuously work without any additional regeneration process. The established LC-TFA remover-MS system has been successfully applied for the qualitative and quantitative analysis of small molecules as well as proteins.

  3. Sigma opiates and certain antipsychotic drugs mutually inhibit (+)-[3H] SKF 10,047 and [3H]haloperidol binding in guinea pig brain membranes.

    PubMed Central

    Tam, S W; Cook, L

    1984-01-01

    The relationship between binding of antipsychotic drugs and sigma psychotomimetic opiates to binding sites for the sigma agonist (+)-[3H]SKF 10,047 (N-allylnormetazocine) and to dopamine D2 sites was investigated. In guinea pig brain membranes, (+)-[3H]SKF 10,047 bound to a single class of sites with a Kd of 4 X 10(-8) M and a Bmax of 333 fmol/mg of protein. This binding was different from mu, kappa, or delta opiate receptor binding. It was inhibited by opiates that produce psychotomimetic activities but not by opiates that lack such activities. Some antipsychotic drugs inhibited (+)-[3H]SKF 10,047 binding with high to moderate affinities in the following order of potency: haloperidol greater than perphenazine greater than fluphenazine greater than acetophenazine greater than trifluoperazine greater than molindone greater than or equal to pimozide greater than or equal to thioridazine greater than or equal to chlorpromazine greater than or equal to triflupromazine. However, there were other antipsychotic drugs such as spiperone and clozapine that showed low affinity for the (+)-[3H]SKF 10,047 binding sites. Affinities of antipsychotic drugs for (+)-[3H]SKF 10,047 binding sites did not correlate with those for [3H]spiperone (dopamine D2) sites. [3H]-Haloperidol binding in whole brain membranes was also inhibited by the sigma opiates pentazocine, cyclazocine, and (+)-SKF 10,047. In the striatum, about half of the saturable [3H]haloperidol binding was to [3H]spiperone (D2) sites and the other half was to sites similar to (+)-[3H]SKF 10,047 binding sites. PMID:6147851

  4. sigma opiates and certain antipsychotic drugs mutually inhibit (+)-(/sup 3/H)SKF 10,047 and (/sup 3/H)haloperidol binding in guinea pig brain membranes

    SciTech Connect

    Tam, S.W.; Cook, L.

    1984-09-01

    The relationship between binding of antipsychotic drugs and sigma psychotomimetic opiates to binding sites for the sigma agonist (+)-(/sup 3/H)SKF 10,047 (N-allylnormetazocine) and to dopamine D/sub 2/ sites was investigated. In guinea pig brain membranes, (+)-(/sup 3/H)SKF 10,047 bound to single class of sites with a K/sub d/ of 4 x 10/sup -8/ M and a B/sub max/ of 333 fmol/mg of protein. This binding was different from ..mu.., kappa, or delta opiate receptor binding. It was inhibited by opiates that produce psychotomimetic activities but not by opiates that lack such activities. Some antipsychotic drugs inhibited (+)-(/sup 3/H)SKF 10,047 binding with high to moderate affinities in the following order of potency: haloperidol > perphenazine > fluphenazine > acetophenazine > trifluoperazine > molindone greater than or equal to pimozide greater than or equal to thioridazine greater than or equal to chlorpromazine greater than or equal to triflupromazine. However, there were other antipsychotic drugs such as spiperone and clozapine that showed low affinity for the (+)-(/sup 3/H)SKF 10,047 binding sites. Affinities of antipsychotic drugs for (+)-(/sup 3/H)SKF 10,047 binding sites did not correlate with those for (/sup 3/H)spiperone (dopamine D/sub 2/) sites. (/sup 3/H)-Haloperidol binding in whole brain membranes was also inhibited by the sigma opiates pentazocine, cyclazocine, and (+)-(/sup 3/H)SKF 10,047. In the striatum, about half of the saturable (/sup 3/H)haloperidol binding was to (/sup 3/H)spiperone (D/sub 2/) sites and the other half was to sites similar to (+)-(/sup 3/H)SKF 10,047 binding sites. 15 references, 4 figures, 1 table.

  5. Activity and Ca2+ regulate the mobility of TRPV1 channels in the plasma membrane of sensory neurons

    PubMed Central

    Senning, Eric N; Gordon, Sharona E

    2015-01-01

    TRPV1 channels are gated by a variety of thermal, chemical, and mechanical stimuli. We used optical recording of Ca2+ influx through TRPV1 to measure activity and mobility of single TRPV1 molecules in isolated dorsal root ganglion neurons and cell lines. The opening of single TRPV1 channels produced sparklets, representing localized regions of elevated Ca2+. Unlike sparklets reported for L-type Ca2+ channels, TRPV4 channels, and AchR channels, TRPV1 channels diffused laterally in the plasma membrane as they gated. Mobility was highly variable from channel-to-channel and, to a smaller extent, from cell to cell. Most surprisingly, we found that mobility decreased upon channel activation by capsaicin, but only in the presence of extracellular Ca2+. We propose that decreased mobility of open TRPV1 could act as a diffusion trap to concentrate channels in cell regions with high activity. DOI: http://dx.doi.org/10.7554/eLife.03819.001 PMID:25569155

  6. Single Molecule Lateral Mobility and Membrane Organization in DMPC/Cholesterol Mixtures at the Air-Water Interface

    NASA Astrophysics Data System (ADS)

    Shaikh, Saame; Stillwell, William; Naumann, Christoph

    2002-03-01

    To better understand the lipid heterogeneity of biological membranes, we have studied the lateral mobility and membrane organization of DMPC and cholesterol (Chol) mixtures at the air-water interface using single molecule fluorescence imaging and epifluorescence microscopy. The single molecule imaging technique was used to track the lateral diffusion of single molecules of TRITC-DPPE or cholesteryl Bodipy. In the absence of Chol, mean square displacement histograms obtained from single molecule tracking of TRITC-DPPE show unobstructed diffusion. Including Chol at low levels of Chol (<10 moldiffusion at intermediate levels ( 30 molof Chol (>40 molmacroscopic phase separations. Data obtained from tracking experiments of cholesteryl-Bodipy also show complementary changes in diffusion. Our results indicate that our techniques provide insight into the micro and macro organization of lipid domains at the air-water interface.

  7. Epidermal growth factor-induced mobilization of a ganglioside-specific sialidase (NEU3) to membrane ruffles

    SciTech Connect

    Yamaguchi, Kazunori; Hata, Keiko; Wada, Tadashi; Moriya, Setsuko; Miyagi, Taeko . E-mail: miyagi-ta173@pref.miyagi.jp

    2006-07-28

    Human ganglioside-specific sialidase, NEU3, localized at cell membranes is thought to regulate various biological processes at cell surfaces. We here explored functional subcellular localization of the sialidase by immunofluorescence and found accumulation at leading edges of cell membranes in the presence of serum in culture. In response to EGF, the sialidase redistributed rapidly to ruffling cell membranes of squamous carcinoma A431 cells and co-localized with Rac-1. NEU3 overexpression enhanced Rac-1 activation and cell migration as compared with controls in HeLa cells as well as in A431 cells. Consistent with co-localization with Rac-1 by immunofluorescence, NEU3 was found to co-precipitate with activated Rac bound to GST-PAK-1 fusion protein. NEU3 silencing by siRNA, in contrast, resulted in inhibition of Rac-1 activation. These results indicate that NEU3 is able to mobilize to membrane ruffles in response to growth stimuli and activate the Rac-1 signaling by co-localization with Rac-1, leading to increased cell motility.

  8. Mobilization

    DTIC Science & Technology

    1987-01-01

    istic and romantic emotionalism that typifies this genre. Longino, James C., et al. “A Study of World War Procurement and Industrial Mobilization...States. Harrisburg, PA: Military Service Publishing Co., 1941. CARL 355.22 J72b. Written in rough prose , this World War II era document explains the

  9. Mutually Exclusive Uncertainty Relations

    PubMed Central

    Xiao, Yunlong; Jing, Naihuan

    2016-01-01

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds. PMID:27824161

  10. Mutually Exclusive Uncertainty Relations.

    PubMed

    Xiao, Yunlong; Jing, Naihuan

    2016-11-08

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds.

  11. Mutually Exclusive Uncertainty Relations

    NASA Astrophysics Data System (ADS)

    Xiao, Yunlong; Jing, Naihuan

    2016-11-01

    The uncertainty principle is one of the characteristic properties of quantum theory based on incompatibility. Apart from the incompatible relation of quantum states, mutually exclusiveness is another remarkable phenomenon in the information- theoretic foundation of quantum theory. We investigate the role of mutual exclusive physical states in the recent work of stronger uncertainty relations for all incompatible observables by Mccone and Pati and generalize the weighted uncertainty relation to the product form as well as their multi-observable analogues. The new bounds capture both incompatibility and mutually exclusiveness, and are tighter compared with the existing bounds.

  12. Evolution of mutualism between species

    SciTech Connect

    Post, W.M.; Travis, C.C.; DeAngelis, D.L.

    1980-01-01

    Recent theoretical work on mutualism, the interaction between species populations that is mutually beneficial, is reviewed. Several ecological facts that should be addressed in the construction of dynamic models for mutualism are examined. Basic terminology is clarified. (PSB)

  13. Weak mutually unbiased bases

    NASA Astrophysics Data System (ADS)

    Shalaby, M.; Vourdas, A.

    2012-02-01

    Quantum systems with variables in { Z}(d) are considered. The properties of lines in the { Z}(d)\\times { Z}(d) phase space of these systems are studied. Weak mutually unbiased bases in these systems are defined as bases for which the overlap of any two vectors in two different bases is equal to d-1/2 or alternatively to one of the d-1/2i, 0 (where di is a divisor of d apart from d, 1). They are designed for the geometry of the { Z}(d)\\times { Z}(d) phase space, in the sense that there is a duality between the weak mutually unbiased bases and the maximal lines through the origin. In the special case of prime d, there are no divisors of d apart from 1, d and the weak mutually unbiased bases are mutually unbiased bases.

  14. Behavioral Ecology: Manipulative Mutualism.

    PubMed

    Hughes, David P

    2015-09-21

    A new study reveals that an apparent mutualism between lycaenid caterpillars and their attendant ants may not be all it seems, as the caterpillars produce secretions that modify the brains and behavior of their attendant ants.

  15. Mobility Measurements Probe Conformational Changes in Membrane Proteins due to Tension

    NASA Astrophysics Data System (ADS)

    Morris, Richard G.; Turner, Matthew S.

    2015-11-01

    The function of membrane-embedded proteins such as ion channels depends crucially on their conformation. We demonstrate how conformational changes in asymmetric membrane proteins may be inferred from measurements of their diffusion. Such proteins cause local deformations in the membrane, which induce an extra hydrodynamic drag on the protein. Using membrane tension to control the magnitude of the deformations, and hence the drag, measurements of diffusivity can be used to infer—via an elastic model of the protein—how conformation is changed by tension. Motivated by recent experimental results [Quemeneur et al., Proc. Natl. Acad. Sci. U.S.A. 111, 5083 (2014)], we focus on KvAP, a voltage-gated potassium channel from Aeropyrum pernix. The conformation of KvAP is found to change considerably due to tension, with its "walls," where the protein meets the membrane, undergoing significant angular strains. The torsional stiffness is determined to be 26.8 kBT per radian at room temperature. This has implications for both the structure and the function of such proteins in the environment of a tension-bearing membrane.

  16. The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants.

    PubMed

    Tyutereva, Elena V; Evkaikina, Anastasiia I; Ivanova, Alexandra N; Voitsekhovskaja, Olga V

    2017-04-05

    The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.

  17. Rapid mobilization of membrane lipids in wheat leaf-sheathes during incompatible interactions with hessian fly

    USDA-ARS?s Scientific Manuscript database

    Hessian fly (Mayetiola destructor) is a biotrophic parasitic insect that interacts with wheat on a typical gene-for-gene basis. In this study, we systematically profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing resistance ge...

  18. Enhanced ionic liquid mobility induced by confinement in 1D CNT membranes.

    PubMed

    Berrod, Q; Ferdeghini, F; Judeinstein, P; Genevaz, N; Ramos, R; Fournier, A; Dijon, J; Ollivier, J; Rols, S; Yu, D; Mole, R A; Zanotti, J-M

    2016-04-21

    Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators.

  19. 47 CFR 22.717 - Procedure for mutually exclusive applications in the Rural Radiotelephone Service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Procedure for mutually exclusive applications... COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Rural Radiotelephone Service § 22.717 Procedure for mutually exclusive applications in the Rural Radiotelephone Service. Mutually...

  20. 47 CFR 22.717 - Procedure for mutually exclusive applications in the Rural Radiotelephone Service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Procedure for mutually exclusive applications... COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Rural Radiotelephone Service § 22.717 Procedure for mutually exclusive applications in the Rural Radiotelephone Service. Mutually exclusive...

  1. [Venoarterial extracorporeal membrane oxygenation in an awake patient : Use of the mobile ECMO team for fulminant pulmonary embolism].

    PubMed

    Keller, D; Lotz, C; Kippnich, M; Adami, P; Kranke, P; Roewer, N; Kredel, M; Schimmer, C; Leyh, R; Muellenbach, R M

    2015-05-01

    The current report highlights the use of venoarterial extracorporeal membrane oxygenation (va-ECMO) in a case of pulmonary embolism complicated by right ventricular failure. A 38-year-old woman was admitted to a secondary care hospital with dyspnea and systemic hypotension. Diagnostic testing revealed a massive pulmonary embolism. Thrombolytic therapy was unsuccessful necessitating thromboendarterectomy in the presence of cardiogenic shock. To allow the necessary transport of the highly unstable patient to a tertiary care center a mobile ECMO team was called in. The team immediately initiated awake va-ECMO as a bridge to therapy. Extracorporeal support subsequently allowed a safe transportation and successful completion of the surgical procedure with complete recovery.

  2. Ambulatory extracorporeal membrane oxygenation with subclavian venoarterial cannulation to increase mobility and recovery in a patient awaiting cardiac transplantation

    PubMed Central

    Jacob, Samuel; MacHannaford, Juan C.; Chamogeorgakis, Themistokles; Gonzalez-Stawinski, Gonzalo V.; Felius, Joost; Rafael, Aldo E.; Malyala, Rajasekhar S.

    2017-01-01

    Venoarterial extracorporeal membrane oxygenation (ECMO) can provide temporary cardiopulmonary support for patients in hemodynamic extremis or refractory heart failure until more durable therapies—such as cardiac transplantation or a left ventricular assist device—can be safely implemented. Conventional ECMO cannulation strategies commonly employ the femoral artery and vein, constraining the patients to the supine position for the duration of ECMO support. We have recently adopted a modified cannulation approach to promote patient mobility, rehabilitation, and faster recovery and to mitigate complications associated with femoral arterial cannulation, such as limb ischemia and compartment syndrome. This technique involves cannulation of the subclavian artery and vein. The current case report details our recent experience with this approach in a critically ill patient awaiting cardiac transplantation.

  3. TRH-receptor mobility and function in intact and cholesterol-depleted plasma membrane of HEK293 cells stably expressing TRH-R-eGFP.

    PubMed

    Brejchová, Jana; Sýkora, Jan; Ostašov, Pavel; Merta, Ladislav; Roubalová, Lenka; Janáček, Jiří; Hof, Martin; Svoboda, Petr

    2015-03-01

    Here we investigated the effect of disruption of plasma membrane integrity by cholesterol depletion on thyrotropin-releasing hormone receptor (TRH-R) surface mobility in HEK293 cells stably expressing TRH-R-eGFP fusion protein (VTGP cells). Detailed analysis by fluorescence recovery after photobleaching (FRAP) in bleached spots of different sizes indicated that cholesterol depletion did not result in statistically significant alteration of mobile fraction of receptor molecules (Mf). The apparent diffusion coefficient (Dapp) was decreased, but this decrease was detectable only under the special conditions of screening and calculation of FRAP data. Analysis of mobility of receptor molecules by raster image correlation spectroscopy (RICS) did not indicate any significant difference between control and cholesterol-depleted cells. Results of our FRAP and RICS experiments may be collectively interpreted in terms of a "membrane fence" model which regards the plasma membrane of living cells as compartmentalized plane where lateral diffusion of membrane proteins is limited to restricted areas by cytoskeleton constraints. Hydrophobic interior of plasma membrane, studied by steady-state and time-resolved fluorescence anisotropy of hydrophobic membrane probe DPH, became substantially more "fluid" and chaotically organized in cholesterol-depleted cells. Decrease of cholesterol level impaired the functional coupling between the receptor and the cognate G proteins of Gq/G11 family. the presence of an unaltered level of cholesterol in the plasma membrane represents an obligatory condition for an optimum functioning of TRH-R signaling cascade. The decreased order and increased fluidity of hydrophobic membrane interior suggest an important role of this membrane area in TRH-R-Gq/G11α protein coupling. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Enhanced ionic liquid mobility induced by confinement in 1D CNT membranes

    NASA Astrophysics Data System (ADS)

    Berrod, Q.; Ferdeghini, F.; Judeinstein, P.; Genevaz, N.; Ramos, R.; Fournier, A.; Dijon, J.; Ollivier, J.; Rols, S.; Yu, D.; Mole, R. A.; Zanotti, J.-M.

    2016-04-01

    Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators.Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01445c

  5. Self-assembly in Nafion membranes upon hydration: water mobility and adsorption isotherms.

    PubMed

    Vishnyakov, Aleksey; Neimark, Alexander V

    2014-09-25

    By means of dissipative particle dynamics (DPD) and Monte Carlo (MC) simulations, we explored geometrical, transport, and sorption properties of hydrated Nafion-type polyelectrolyte membranes. Composed of a perfluorinated backbone with sulfonate side chains, Nafion self-assembles upon hydration and segregates into interpenetrating hydrophilic and hydrophobic subphases. This segregated morphology determines the transport properties of Nafion membranes that are widely used as compartment separators in fuel cells and other electrochemical devices, as well as permselective diffusion barriers in protective fabrics. We introduced a coarse-grained model of Nafion, which accounts explicitly for polymer rigidity and electrostatic interactions between anionic side chains and hydrated metal cations. In a series of DPD simulations with increasing content of water, a classical percolation transition from a system of isolated water clusters to a 3D network of hydrophilic channels was observed. The hydrophilic subphase connectivity and water diffusion were studied by constructing digitized replicas of self-assembled morphologies and performing random walk simulations. A non-monotonic dependence of the tracer diffusivity on the water content was found. This unexpected behavior was explained by the formation of large and mostly isolated water domains detected at high water content and high equivalent polymer weight. Using MC simulations, we calculated the chemical potential of water in the hydrated polymer and constructed the water sorption isotherms, which extended to the oversaturated conditions. We determined that the maximum diffusivity and the onset of formation of large water domains corresponded to the saturation conditions at 100% humidity. The oversaturated membrane morphologies generated in the canonical ensemble DPD simulations correspond to the metastable and unstable states of Nafion membrane that are not realized in the experiments.

  6. Mutually Exclusive, Complementary, or . . .

    ERIC Educational Resources Information Center

    Schloemer, Cathy G.

    2016-01-01

    Whether students are beginning their study of probability or are well into it, distinctions between complementary sets and mutually exclusive sets can be confusing. Cathy Schloemer writes in this article that for years she used typical classroom examples but was not happy with the student engagement or the level of understanding they produced.…

  7. Mutually Exclusive, Complementary, or . . .

    ERIC Educational Resources Information Center

    Schloemer, Cathy G.

    2016-01-01

    Whether students are beginning their study of probability or are well into it, distinctions between complementary sets and mutually exclusive sets can be confusing. Cathy Schloemer writes in this article that for years she used typical classroom examples but was not happy with the student engagement or the level of understanding they produced.…

  8. Mutual Adaptaion in Action

    ERIC Educational Resources Information Center

    Siskin, Leslie Santee

    2016-01-01

    Building on an expanded concept of mutual adaptation, this chapter explores a distinctive and successful aspect of International Baccalaureate's effort to scale up, as they moved to expand their programs and support services in Title I schools. Based on a three-year, mixed-methods study, it offers a case where we see not only local adaptations…

  9. Mutual Adaptaion in Action

    ERIC Educational Resources Information Center

    Siskin, Leslie Santee

    2016-01-01

    Building on an expanded concept of mutual adaptation, this chapter explores a distinctive and successful aspect of International Baccalaureate's effort to scale up, as they moved to expand their programs and support services in Title I schools. Based on a three-year, mixed-methods study, it offers a case where we see not only local adaptations…

  10. Survival, mobility, and membrane-bound enzyme activities of freshwater planarian, Dugesia japonica, exposed to synthetic and natural surfactants.

    PubMed

    Li, Mei-Hui

    2012-04-01

    Surfactants are a major class of emerging pollutants widely used in large quantities in everyday life and commonly found in surface waters worldwide. Freshwater planarian was selected to examine the effects of different surfactants by measuring mortality, mobility, and membrane-bound enzyme activities. Among the 10 surfactants tested, the acute toxicities of betaine and polyethylene glycol (PEG-200) to planarians were relatively low, with a median lethal concentration (LC50) greater than 10,000 mg/L. The toxicity to planarians of the other eight surfactants based on 48-h LC50 could be arranged in the descending order of cetylpyridinum chloride (CPC) > 4-tert-octylphenol (4-tert-OP) > ammonium lauryl sulfate > benzalkonium chloride > saponin > sodium lauroylsarcosinate > dioctyl sulfosuccinate > dodecyl trimethyl ammonium bromide (DTAB). Both CPC and 4-tert-OP were very toxic to planarians, with 48-h LC50 values <1 mg/L. The median effective concentrations (EC50s) of planarian mobility were in the 0.1 to 50 mg/L range and were in the same range as the 24-h LC50 of planarians exposed to different surfactants, except for DTAB. In addition, significant inhibition of cholinesterase activity activities was found in planarians exposed to 4-tert-OP at 2.5 and 5 mg/L and to saponin at 10 mg/L after 2-h treatments. This result suggests that planarian mobility responses can be used as an alternative indicator for acute toxicity of surfactants after a very short exposure period. Copyright © 2012 SETAC.

  11. Mutual information algorithms

    NASA Astrophysics Data System (ADS)

    Jiang, Ai-Hua; Huang, Xiu-Chang; Zhang, Zhen-Hua; Li, Jun; Zhang, Zhi-Yi; Hua, Hong-Xin

    2010-11-01

    Three new mutual information algorithms are raised for time delay in the phase space reconstruction process. Firstly, Cellucci's mutual information algorithm is analyzed based on partitioning plane, which is constructed by a pair of Lorenz series with the same size, into four and sixteen grids with equal distribution probability in elements on each axis. Then three new mutual information algorithms are promoted based on the original probability matrix that shows the distribution of points corresponding to the data pairs of Lorenz series on the plane, the matrix excluding the last column and the last row of the original one as well as the proportionally revised matrix from the original one. Synchronously, an algorithm to compute the probability matrix is also advanced by sorting two series and replacing each numerical value with its order number in its own series so as to judge the element in which data sets are located. The optimal time delay of the three new mutual information algorithms as well as the computing time is also compared when series sizes are different. Finally, after reconstructing phase space with the optimal time delay, comparison between the maximal Lyapunov exponent calculated by Rosenstein's algorithm from time series and that gained by Jacobi matrix from Lorenz equation is used to confirm the validity of the new mutual information algorithms. The results show that Cellucci's mutual information algorithm will lead to wrong optimal time delay when series size is not a multiple of elements. The three new algorithms, whose results are more steady when a large number of data pairs are used, can not only eliminate the default of Cellucci's algorithm but also is very speedy, and the time spent on calculations by three algorithms nearly enhances linearly with the increase in series size. Moreover, the algorithm using original probability distribution matrix is more accurate than the others when small size series are used, and is also faster than the

  12. Mobility of integrin alpha5beta1 measured on the isolated ventral membranes of human skin fibroblasts.

    PubMed

    Hirata, Hiroaki; Ohki, Kazuo; Miyata, Hidetake

    2005-05-25

    We have measured the lateral mobility of individual alpha5 integrin molecules in ventral plasma membranes of fibroblasts, which were prepared by removal of apical surfaces and nuclei followed by elimination of actin filaments with gelsolin, an actin-severing protein. The cytoplasmic domain of individual integrin molecules was tagged with 100 nm fluorescent polystyrene bead, and motion of the bead was observed and video-recorded. Position of the bead in each frame was determined from the centroid of the fluorescence image, from which plots of the mean-square displacement against time intervals were derived. Within short intervals of time (<100 ms) the mean-square displacement was proportional to the time interval, and the averaged translational diffusion coefficient of (5.3+/-4.4) x 10(-10) cm2/s was obtained with a broad distribution of (1.3-20) x 10(-10) cm2/s. The broad distribution might reflect the oligomerized state of integrin. The largest diffusion coefficient was comparable to that of lipid molecules previously measured in cells and probably represented the diffusion of a single integrin molecule in the presence of little interference of actin cytoskeleton or extracellular matrix. In longer time intervals (>100 ms) the motion of the bead was confined in an area, the average diameter of which was 410+/-160 nm. This was similar to the values described in previous reports, in which the motion of other membrane receptors labeled on their extracellular domain was measured in living cells.

  13. Formation of a Mast Cell Synapse: FcεRI Membrane Dynamics upon Binding Mobile or Immobilized Ligands on Surfaces1

    PubMed Central

    Carroll-Portillo, Amanda; Spendier, Kathrin; Pfeiffer, Janet; Griffiths, Gary; Li, Haitao; Lidke, Keith A.; Oliver, Janet M.; Lidke, Diane S.; Thomas, James L.; Wilson, Bridget S.; Timlin, Jerilyn A.

    2011-01-01

    High affinity IgE receptors (FcεRI) on mast cells form a “synapse” when presented with mobile, bilayer incorporated antigen. Here, we show that receptor reorganization within the contacting mast cell membrane is markedly different upon binding of mobile and immobilized ligands. Rat basophilic leukemia mast cells (RBL-2H3) primed with fluorescent anti-DNP IgE were engaged by surfaces presenting either bilayer-incorporated, monovalent DNP-lipid (mobile ligand) or chemically crosslinked, multivalent DNP (immobilized ligand). Total internal reflection fluorescence imaging and electron microscopy methods were used to visualize receptor reorganization at the contact site. The spatial relationships of FcεRI to other cellular components at the synapse, such as actin, cholesterol and LAT, were also analyzed. Stimulation of mast cells with immobilized polyvalent ligand resulted in typical levels of degranulation. Remarkably, degranulation also followed interaction of mast cells with bilayers presenting mobile, monovalent ligand. Receptors engaged with mobile ligand coalesce into large, cholesterol-rich clusters that occupy the central portion of the contacting membrane. These data indicate that FcεRI crosslinking is not an obligatory step in triggering mast cell signaling and suggest that dense populations of mobile receptors are capable of initiating low level degranulation upon ligand recognition. PMID:20042583

  14. Interhospital Transport System for Critically Ill Patients: Mobile Extracorporeal Membrane Oxygenation without a Ventilator

    PubMed Central

    Yeo, Hye Ju; Cho, Woo Hyun; Park, Jong Myung; Kim, Dohyung

    2017-01-01

    Background Extracorporeal membrane oxygenation (ECMO) has been successfully used as a method for the interhospital transportation of critically ill patients. In South Korea, a well-established ECMO interhospital transport system is lacking due to limited resources. We developed a simplified ECMO transport system without mechanical ventilation for use by public emergency medical services. Methods Eighteen patients utilized our ECMO transport system from December 2011 to September 2015. We retrospectively analyzed the indications for ECMO, the patient status during transport, and the patient outcomes. Results All transport was conducted on the ground by ambulance. The distances covered ranged from 26 to 408 km (mean, 65.9±88.1 km) and the average transport time was 56.1±57.3 minutes (range, 30 to 280 minutes). All patients were transported without adverse events. After transport, 4 patients (22.2%) underwent lung transplantation because of interstitial lung disease. Eight patients who had severe acute respiratory distress syndrome showed recovery of heart and lung function after ECMO therapy. A total of 13 patients (70.6%) were successfully taken off ECMO, and 11 patients (61.1%) survived. Conclusion Our ECMO transport system without mechanical ventilation can be considered a safe and useful method for interhospital transport and could be a good alternative option for ECMO transport in Korean hospitals with limited resources. PMID:28180097

  15. Lateral mobility of plasma membrane lipids in Xenopus eggs: regional differences related to animal/vegetal polarity become extreme upon fertilization.

    PubMed

    Dictus, W J; van Zoelen, E J; Tetteroo, P A; Tertoolen, L G; de Laat, S W; Bluemink, J G

    1984-01-01

    Regional differences in the lateral mobility properties of plasma membrane lipids have been studied in unfertilized and fertilized Xenopus eggs by fluorescence photobleaching recovery (FPR) measurements. Out of a variety of commonly used lipid probes only the aminofluorescein-labeled fatty acids HEDAF (5-(N-hexadecanoyl)-aminofluorescein) and TEDAF (5-(N-tetradecanoyl)-aminofluorescein) appear to partition into the plasma membrane. Under all experimental conditions used these molecules show partial recovery upon photobleaching indicating the existence of lipidic microdomains. In the unfertilized egg the mobile fraction of plasma membrane lipids (approximately 50%) has a fivefold smaller lateral diffusion coefficient (D = 1.5 X 10(-8) cm2/sec) in the animal than in the vegetal plasma membrane (D = 7.6 X 10(-8) cm2/sec). This demonstrates the presence of an animal/vegetal polarity within the Xenopus egg plasma membrane. Upon fertilization this polarity is strongly (greater than 100X) enhanced leading to the formation of two distinct macrodomains within the plasma membrane. At the animal side of the egg lipids are completely immobilized on the time scale of FPR measurements (D less than 10(-10) cm2/sec), whereas at the vegetal side D is only slightly reduced (D = 4.4 X 10(-8) cm2/sec). The immobilization of animal plasma membrane lipids, which could play a role in the polyspermy block, probably arises by the fusion of cortical granules which are more numerous here. The transition between the animal and the vegetal domain is sharp and coincides with the boundary between the presumptive ecto- and endoderm. The role of regional differences in the plasma membrane is discussed in relation to cell diversification in early development.

  16. Early mobilization of patients receiving extracorporeal membrane oxygenation: a retrospective cohort study.

    PubMed

    Abrams, Darryl; Javidfar, Jeffrey; Farrand, Erica; Mongero, Linda B; Agerstrand, Cara L; Ryan, Patrick; Zemmel, David; Galuskin, Keri; Morrone, Theresa M; Boerem, Paul; Bacchetta, Matthew; Brodie, Daniel

    2014-02-27

    Critical illness is a well-recognized cause of neuromuscular weakness and impaired physical functioning. Physical therapy (PT) has been demonstrated to be safe and effective for critically ill patients. The impact of such an intervention on patients receiving extracorporeal membrane oxygenation (ECMO) has not been well characterized. We describe the feasibility and impact of active PT on ECMO patients. We performed a retrospective cohort study of 100 consecutive patients receiving ECMO in the medical intensive care unit of a university hospital. Of the 100 patients receiving ECMO, 35 (35%) participated in active PT; 19 as bridge to transplant and 16 as bridge to recovery. Duration of ECMO was 14.3 ± 10.9 days. Patients received 7.2 ± 6.5 PT sessions while on ECMO. During PT sessions, 18 patients (51%) ambulated (median distance 175 feet, range 4 to 2,800) and 9 patients were on vasopressors. Whilst receiving ECMO, 23 patients were liberated from invasive mechanical ventilation. Of the 16 bridge to recovery patients, 14 (88%) survived to discharge; 10 bridge to transplant patients (53%) survived to transplantation, with 9 (90%) surviving to discharge. Of the 23 survivors, 13 (57%) went directly home, 8 (35%) went to acute rehabilitation, and 2 (9%) went to subacute rehabilitation. There were no PT-related complications. Active PT, including ambulation, can be achieved safely and reliably in ECMO patients when an experienced, multidisciplinary team is utilized. More research is needed to define the barriers to PT and the impact on survival and long-term functional, neurocognitive outcomes in this population.

  17. Examining in vivo tympanic membrane mobility using smart phone video-otoscopy and phase-based Eulerian video magnification

    NASA Astrophysics Data System (ADS)

    Janatka, Mirek; Ramdoo, Krishan S.; Tatla, Taran; Pachtrachai, Krittin; Elson, Daniel S.; Stoyanov, Danail

    2017-03-01

    The tympanic membrane (TM) is the bridging element between the pressure waves of sound in air and the ossicular chain. It allows for sound to be conducted into the inner ear, achieving the human sense of hearing. Otitis media with effusion (OME, commonly referred to as `glue ear') is a typical condition in infants that prevents the vibration of the TM and causes conductive hearing loss, this can lead to stunting early stage development if undiagnosed. Furthermore, OME is hard to identify in this age group; as they cannot respond to typical audiometry tests. Tympanometry allows for the mobility of the TM to be examined without patient response, but requires expensive apparatus and specialist training. By combining a smartphone equipped with a 240 frames per second video recording capability with an otoscopic clip-on accessory, this paper presents a novel application of Eulerian Video Magnification (EVM) to video-otology, that could provide assistance in diagnosing OME. We present preliminary results showing a spatio-temporal slice taken from an exaggerated video visualization of the TM being excited in vivo on a healthy ear. Our preliminary results demonstrate the potential for using such an approach for diagnosing OME under visual inspection as alternative to tympanometry, which could be used remotely and hence help diagnosis in a wider population pool.

  18. Mutual help in SETIs

    NASA Astrophysics Data System (ADS)

    Melia, F.; Frisch, D. H.

    1985-06-01

    Techniques to establish communication between earth and extraterrestrial intelligent beings are examined analytically, emphasizing that the success of searches for extraterrestrial intelligence (SETIs) depends on the selection by both sender and receiver of one of a few mutually helpful SETI strategies. An equation for estimating the probability that an SETI will result in the recognition of an ETI signal is developed, and numerical results for various SETI strategies are presented in tables. A minimum approach employing 10 40-m 20-kW dish antennas for a 30-yr SETI in a 2500-light-year disk is proposed.

  19. Cheaters in mutualism networks.

    PubMed

    Genini, Julieta; Morellato, L Patrícia C; Guimarães, Paulo R; Olesen, Jens M

    2010-08-23

    Mutualism-network studies assume that all interacting species are mutualistic partners and consider that all links are of one kind. However, the influence of different types of links, such as cheating links, on network organization remains unexplored. We studied two flower-visitation networks (Malpighiaceae and Bignoniaceae and their flower visitors), and divide the types of link into cheaters (i.e. robbers and thieves of flower rewards) and effective pollinators. We investigated if there were topological differences among networks with and without cheaters, especially with respect to nestedness and modularity. The Malpighiaceae network was nested, but not modular, and it was dominated by pollinators and had much fewer cheater species than Bignoniaceae network (28% versus 75%). The Bignoniaceae network was mainly a plant-cheater network, being modular because of the presence of pollen robbers and showing no nestedness. In the Malpighiaceae network, removal of cheaters had no major consequences for topology. In contrast, removal of cheaters broke down the modularity of the Bignoniaceae network. As cheaters are ubiquitous in all mutualisms, the results presented here show that they have a strong impact upon network topology.

  20. Cheaters in mutualism networks

    PubMed Central

    Genini, Julieta; Morellato, L. Patrícia C.; Guimarães, Paulo R.; Olesen, Jens M.

    2010-01-01

    Mutualism-network studies assume that all interacting species are mutualistic partners and consider that all links are of one kind. However, the influence of different types of links, such as cheating links, on network organization remains unexplored. We studied two flower-visitation networks (Malpighiaceae and Bignoniaceae and their flower visitors), and divide the types of link into cheaters (i.e. robbers and thieves of flower rewards) and effective pollinators. We investigated if there were topological differences among networks with and without cheaters, especially with respect to nestedness and modularity. The Malpighiaceae network was nested, but not modular, and it was dominated by pollinators and had much fewer cheater species than Bignoniaceae network (28% versus 75%). The Bignoniaceae network was mainly a plant–cheater network, being modular because of the presence of pollen robbers and showing no nestedness. In the Malpighiaceae network, removal of cheaters had no major consequences for topology. In contrast, removal of cheaters broke down the modularity of the Bignoniaceae network. As cheaters are ubiquitous in all mutualisms, the results presented here show that they have a strong impact upon network topology. PMID:20089538

  1. Covariant mutually unbiased bases

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Schultz, Jussi; Toigo, Alessandro

    2016-06-01

    The connection between maximal sets of mutually unbiased bases (MUBs) in a prime-power dimensional Hilbert space and finite phase-space geometries is well known. In this article, we classify MUBs according to their degree of covariance with respect to the natural symmetries of a finite phase-space, which are the group of its affine symplectic transformations. We prove that there exist maximal sets of MUBs that are covariant with respect to the full group only in odd prime-power dimensional spaces, and in this case, their equivalence class is actually unique. Despite this limitation, we show that in dimension 2r covariance can still be achieved by restricting to proper subgroups of the symplectic group, that constitute the finite analogues of the oscillator group. For these subgroups, we explicitly construct the unitary operators yielding the covariance.

  2. Analysis of a Chinese hamster ovary cell mutant with defective mobilization of cholesterol from the plasma membrane to the endoplasmic reticulum.

    PubMed

    Jacobs, N L; Andemariam, B; Underwood, K W; Panchalingam, K; Sternberg, D; Kielian, M; Liscum, L

    1997-10-01

    The factors involved in shuttling cholesterol among cellular membranes have not been defined. Using amphotericin B selection, we previously isolated Chinese hamster ovary cell mutants expressing defects in intracellular cholesterol transport. Complementation analysis among seven mutants identified one cell line, mutant 3-6, with a unique defect. The present analysis revealed three key features of mutant 3-6. First, the movement of cholesterol both from the endoplasmic reticulum and through lysosomes to the plasma membrane was normal. However, when intact 3-6 cells were treated with sphingomyelinase, movement of plasma membrane cholesterol to acyl CoA:cholesterol acyltransferase in the endoplasmic reticulum was defective. Cellular cholesterol was mobilized to this enzyme upon activation by 25-hydroxycholesterol. Second, mutant 3-6 did not utilize endogenously synthesized sterol or low density lipoprotein-derived cholesterol for growth as effectively as parental Chinese hamster ovary cells. Finally, despite normal movement of cholesterol to the plasma membrane, mutant 3-6 was amphotericin B resistant. The plasma membrane cholesterol content was normal as assessed by cholesterol oxidase treatment and Semliki Forest virus fusion, which suggests that the 3-6 mutation alters the organization of cholesterol in the plasma membrane. Our characterization of this mutant cell line should facilitate the identification of gene(s) required for this transport pathway.

  3. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Wilkes, Robert; Kuehnel, Eric

    2014-01-01

    Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the Generation 4 Spacesuit Water Membrane Evaporator (Gen4 SWME). The SWME offers several advantages when compared with prior crewmember cooling technologies, including the ability to reject heat at increased atmospheric pressures, reduced loop infrastructure, and higher tolerance to fouling. Like its predecessors, Gen4 SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Test results from the backup cooling system which is based on a similar design and the subject of a companion paper, suggested that further volume reductions could be achieved through fiber density optimization. Testing was performed with four fiber bundle configurations ranging from 35,850 fibers to 41,180 fibers. The optimal configuration reduced the Gen4 SWME envelope volume by 15% from that of Gen3 while dramatically increasing the performance margin of the system. A rectangular block design was chosen over the Gen3 cylindrical design, for packaging configurations within the AEMU PLSS envelope. Several important innovations were made in the redesign of the backpressure valve which is used to control evaporation. A twin-port pivot concept was selected from among three low profile valve designs for superior robustness, control and packaging. The backpressure valve motor, the thermal control valve, delta pressure sensors and temperature sensors were incorporated into the manifold endcaps, also for packaging considerations. Flight-like materials including a titanium housing were used for all components. Performance testing

  4. 26 CFR 1.831-1 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, and...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... mutual), mutual marine insurance companies, and mutual fire insurance companies issuing perpetual... insurance companies (other than life or mutual), mutual marine insurance companies, and mutual fire... marine insurance companies and mutual fire insurance companies exclusively issuing either...

  5. Mobility of ribosomes bound to microsomal membranes. A freeze-etch and thin-section electron microscope study of the structure and fluidity of the rough endoplasmic reticulum

    PubMed Central

    1977-01-01

    The lateral mobility of ribosomes bound to rough endoplasmic reticulum (RER) membranes was demonstrated under experimental conditions. High- salt-washed rough microsomes were treated with pancreatic ribonuclease (RNase) to cleave the mRNA of bound polyribosomes and allow the movement of individual bound ribosomesmfreeze-etch and thin-section electron microscopy demonstrated that, when rough microsomes were treated with RNase at 4 degrees C and then maintained at this temperature until fixation, the bound ribosomes retained their homogeneous distribution on the microsomal surface. However, when RNase- treated rough microsomes were brought to 24 degrees C, a temperature above the thermotropic phase transition of the microsomal phospholipids, bound ribosomes were no longer distributed homogeneously but, instead, formed large, tightly packed aggregates on the microsomal surface. Bound polyribosomes could also be aggregated by treating rough microsomes with antibodies raised against large ribosomal subunit proteins. In these experiments, extensive cross-linking of ribosomes from adjacent microsomes also occurred, and large ribosome-free membrane areas were produced. Sedimentation analysis in sucrose density gradients demonstrated that the RNase treatment did not release bound ribosomes from the membranes; however, the aggregated ribosomes remain capable of peptide bond synthesis and were released by puromycin. It is proposed that the formation of ribosomal aggregates on the microsomal surface results from the lateral displacement of ribosomes along with their attached binding sites, nascent polypeptide chains, and other associated membrane proteins; The inhibition of ribosome mobility after maintaining rough microsomes at 4 degrees C after RNase, or antibody, treatment suggests that the ribosome binding sites are integral membrane proteins and that their mobility is controlled by the fluidity of the RER membrane. Examination of the hydrophobic interior of microsomal

  6. International Mutual Recognition: Progress and Prospects. Working Paper.

    ERIC Educational Resources Information Center

    Hager, Paul

    Increasing the mobility of service providers, including professionals, via mutual recognition (of regulatory systems) agreements (MRAs) has become a significant issue worldwide. Despite increasing interest in MRAs, it may be argued that MRAs are but one of a larger range of major developments that have fueled current interest in occupational…

  7. Estimating mutual information

    NASA Astrophysics Data System (ADS)

    Kraskov, Alexander; Stögbauer, Harald; Grassberger, Peter

    2004-06-01

    We present two classes of improved estimators for mutual information M(X,Y) , from samples of random points distributed according to some joint probability density μ(x,y) . In contrast to conventional estimators based on binnings, they are based on entropy estimates from k -nearest neighbor distances. This means that they are data efficient (with k=1 we resolve structures down to the smallest possible scales), adaptive (the resolution is higher where data are more numerous), and have minimal bias. Indeed, the bias of the underlying entropy estimates is mainly due to nonuniformity of the density at the smallest resolved scale, giving typically systematic errors which scale as functions of k/N for N points. Numerically, we find that both families become exact for independent distributions, i.e. the estimator M̂ (X,Y) vanishes (up to statistical fluctuations) if μ(x,y)=μ(x)μ(y) . This holds for all tested marginal distributions and for all dimensions of x and y . In addition, we give estimators for redundancies between more than two random variables. We compare our algorithms in detail with existing algorithms. Finally, we demonstrate the usefulness of our estimators for assessing the actual independence of components obtained from independent component analysis (ICA), for improving ICA, and for estimating the reliability of blind source separation.

  8. [Biological mutualism, concepts and models].

    PubMed

    Perru, Olivier

    2011-01-01

    Mutualism is a biological association for a mutual benefit between two different species. In this paper, firstly, we examine the history and signification of mutualism in relation to symbiosis. Then, we consider the link between concepts and models of mutualism. Models of mutualism depend on different concepts we use: If mutualism is situated at populations' level, it will be expressed by Lotka-Volterra models, concerning exclusively populations' size. If mutualism is considered as a resources' exchange or a biological market increasing the fitness of these organisms, it will be described at an individual level by a cost-benefit model. Our analysis will be limited to the history and epistemology of Lotka-Volterra models and we hypothesize that these models are adapted at first to translate dynamic evolutions of mutualism. They render stability or variations of size and assume that there are clear distinctions and a state of equilibrium between populations of different species. Italian mathematician Vito Volterra demonstrated that biological associations consist in a constant relation between some species. In 1931 and 1935, Volterra described the general form of antagonistic or mutualistic biological associations by the same differential equations. We recognize that these equations have been more used to model competition or prey-predator interactions, but a simple sign change allows describing mutualism. The epistemological problem is the following: Volterra's equations help us to conceptualize a global phenomenon. However, mutualistic interactions may have stronger effects away from equilibrium and these effects may be better understood at individual level. We conclude that, between 1985 and 2000, some researchers carried on working and converting Lotka-Volterra models but this description appeared as insufficient. So, other researchers adopted an economical viewpoint, considering mutualism as a biological market.

  9. 47 CFR 90.720 - Channels available for public safety/mutual aid.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Channels available for public safety/mutual aid... Frequencies in the 220-222 MHz Band § 90.720 Channels available for public safety/mutual aid. (a) Part 90... rule to use mobile and/or portable units on Channels 161-170 throughout the United States,...

  10. 47 CFR 22.509 - Procedures for mutually exclusive applications in the Paging and Radiotelephone Service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Procedures for mutually exclusive applications... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.509 Procedures for mutually exclusive applications in the Paging and Radiotelephone...

  11. 47 CFR 22.509 - Procedures for mutually exclusive applications in the Paging and Radiotelephone Service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Procedures for mutually exclusive applications... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.509 Procedures for mutually exclusive applications in the Paging and Radiotelephone Service...

  12. Laterally Mobile, Functionalized Self-Assembled Monolayers at the Fluorous−Aqueous Interface in a Plug-Based Microfluidic System: Characterization and Testing with Membrane Protein Crystallization

    SciTech Connect

    Kreutz, Jason E.; Li, Liang; Roach, L. Spencer; Hatakeyama, Takuji; Ismagilov, Rustem F.

    2009-11-04

    This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, complementary to current SAM and lipid methods, for rapidly generating mobile, functionalized SAMs. This method relies on plugs, droplets surrounded by a fluorous carrier fluid, to rapidly explore chemical space. Specifically, we implemented his-tag binding chemistry to design a new fluorinated amphiphile, RfNTA, using an improved one-step synthesis of RfOEG under Mitsunobu conditions. RfNTA introduces specific binding of protein at the fluorous-aqueous interface, which concentrates and orients proteins at the interface, even in the presence of other surfactants. We then applied this approach to the crystallization of a his-tagged membrane protein, Reaction Center from Rhodobacter sphaeroides, performed 2400 crystallization trials, and showed that this approach can increase the range of crystal-producing conditions, the success rate at a given condition, the rate of nucleation, and the quality of the crystal formed.

  13. Proton Transfer Dynamics at the Membrane/Water Interface: Dependence on the Fixed and Mobile pH Buffers, on the Size and Form of Membrane Particles, and on the Interfacial Potential Barrier

    PubMed Central

    Cherepanov, Dmitry A.; Junge, Wolfgang; Mulkidjanian, Armen Y.

    2004-01-01

    Crossing the membrane/water interface is an indispensable step in the transmembrane proton transfer. Elsewhere we have shown that the low dielectric permittivity of the surface water gives rise to a potential barrier for ions, so that the surface pH can deviate from that in the bulk water at steady operation of proton pumps. Here we addressed the retardation in the pulsed proton transfer across the interface as observed when light-triggered membrane proton pumps ejected or captured protons. By solving the system of diffusion equations we analyzed how the proton relaxation depends on the concentration of mobile pH buffers, on the surface buffer capacity, on the form and size of membrane particles, and on the height of the potential barrier. The fit of experimental data on proton relaxation in chromatophore vesicles from phototropic bacteria and in bacteriorhodopsin-containing membranes yielded estimates for the interfacial potential barrier for H+/OH− ions of ∼120 meV. We analyzed published data on the acceleration of proton equilibration by anionic pH buffers and found that the height of the interfacial barrier correlated with their electric charge ranging from 90 to 120 meV for the singly charged species to >360 meV for the tetra-charged pyranine. PMID:14747306

  14. ' q-Titration' of long-chain and short-chain lipids differentiates between structured and mobile residues of membrane proteins studied in bicelles by solution NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Son, Woo Sung; Park, Sang Ho; Nothnagel, Henry J.; Lu, George J.; Wang, Yan; Zhang, Hua; Cook, Gabriel A.; Howell, Stanley C.; Opella, Stanley J.

    2012-01-01

    ' q-Titration' refers to the systematic comparison of signal intensities in solution NMR spectra of uniformly 15N labeled membrane proteins solubilized in micelles and isotropic bicelles as a function of the molar ratios ( q) of the long-chain lipids (typically DMPC) to short-chain lipids (typically DHPC). In general, as q increases, the protein resonances broaden and correspondingly have reduced intensities due to the overall slowing of protein reorientation. Since the protein backbone signals do not broaden uniformly, the differences in line widths (and intensities) enable the narrower (more intense) signals associated with mobile residues to be differentiated from the broader (less intense) signals associated with "structured" residues. For membrane proteins with between one and seven trans-membrane helices in isotropic bicelles, we have been able to find a value of q between 0.1 and 1.0 where only signals from mobile residues are observed in the spectra. The signals from the structured residues are broadened so much that they cannot be observed under standard solution NMR conditions. This q value corresponds to the ratio of DMPC:DHPC where the signals from the structured residues are "titrated out" of the spectrum. This q value is unique for each protein. In magnetically aligned bilayers ( q > 2.5) no signals are observed in solution NMR spectra of membrane proteins because the polypeptides are "immobilized" by their interactions with the phospholipid bilayers on the relevant NMR timescale (˜10 5 Hz). No signals are observed from proteins in liposomes (only long-chain lipids) either. We show that it is feasible to obtain complementary solution NMR and solid-state NMR spectra of the same membrane protein, where signals from the mobile residues are present in the solution NMR spectra, and signals from the structured residues are present in the solid-state NMR spectra. With assigned backbone amide resonances, these data are sufficient to describe major features

  15. Mutual Help for the Widowed

    ERIC Educational Resources Information Center

    Abrahams, Ruby Banks

    1972-01-01

    The Widowed Service Line, a mutual help program in metropolitan Boston that provided service by telephone, effectively meeting the various problems and needs of differing stages of widowhood, is described. (Author)

  16. Uncertainty relation for mutual information

    NASA Astrophysics Data System (ADS)

    Schneeloch, James; Broadbent, Curtis J.; Howell, John C.

    2014-12-01

    We postulate the existence of a universal uncertainty relation between the quantum and classical mutual informations between pairs of quantum systems. Specifically, we propose that the sum of the classical mutual information, determined by two mutually unbiased pairs of observables, never exceeds the quantum mutual information. We call this the complementary-quantum correlation (CQC) relation and prove its validity for pure states, for states with one maximally mixed subsystem, and for all states when one measurement is minimally disturbing. We provide results of a Monte Carlo simulation suggesting that the CQC relation is generally valid. Importantly, we also show that the CQC relation represents an improvement to an entropic uncertainty principle in the presence of a quantum memory, and that it can be used to verify an achievable secret key rate in the quantum one-time pad cryptographic protocol.

  17. Granulophysin is located in the membrane of azurophilic granules in human neutrophils and mobilizes to the plasma membrane following cell stimulation.

    PubMed Central

    Cham, B. P.; Gerrard, J. M.; Bainton, D. F.

    1994-01-01

    Granulophysin, a protein described in platelet dense granule membranes, has been shown to be similar or identical to CD63, a lysosomal membrane protein. We have previously shown granulophysin to be present in neutrophils using immunofluorescence. We now localize granulophysin to the neutrophil azurophilic granules by fine structural immunocytochemistry. Granulophysin expression on the surface membrane of the neutrophil is increased following stimulation of the cells, demonstrated by flow cytometry and fine structural immunocytochemistry. A similar pattern is shown for an anti-CD63 antibody. Incubation of activated neutrophils with D545, a monoclonal antibody to granulophysin, blocks subsequent binding of anti-CD63 antibodies to the cell surface, and anti-CD63 antibodies prevent subsequent binding of D545 as assessed by flow cytometry and immunoblotting. Our results support the homology of CD63 and granulophysin previously demonstrated in platelets and confirm CD63 as an activation marker in neutrophils and the first azurophilic granule membrane marker of neutrophils. Images Figure 1 Figure 2 Figure 3 Figure 6 Figure 9 Figure 10 Figure 11 Figure 12 PMID:8203473

  18. Planar Supported Membranes with Mobile SNARE Proteins and Quantitative Fluorescence Microscopy Assays to Study Synaptic Vesicle Fusion

    PubMed Central

    Kiessling, Volker; Liang, Binyong; Kreutzberger, Alex J. B.; Tamm, Lukas K.

    2017-01-01

    Synaptic vesicle membrane fusion, the process by which neurotransmitter gets released at the presynaptic membrane is mediated by a complex interplay between proteins and lipids. The realization that the lipid bilayer is not just a passive environment where other molecular players like SNARE proteins act, but is itself actively involved in the process, makes the development of biochemical and biophysical assays particularly challenging. We summarize in vitro assays that use planar supported membranes and fluorescence microscopy to address some of the open questions regarding the molecular mechanisms of SNARE-mediated membrane fusion. Most of the assays discussed in this mini-review were developed in our lab over the last 15 years. We emphasize the sample requirements that we found are important for the successful application of these methods. PMID:28360838

  19. Hybrid elastic and discrete-particle approach to biomembrane dynamics with application to the mobility of curved integral membrane proteins.

    PubMed

    Naji, Ali; Atzberger, Paul J; Brown, Frank L H

    2009-04-03

    We introduce a simulation strategy to consistently couple continuum biomembrane dynamics to the motion of discrete biological macromolecules residing within or on the membrane. The methodology is used to study the diffusion of integral membrane proteins that impart a curvature on the bilayer surrounding them. Such proteins exhibit a substantial reduction in diffusion coefficient relative to "flat" proteins; this effect is explained by elementary hydrodynamic considerations.

  20. Promotion of progressive mobility activities with ventricular assist and extracorporeal membrane oxygenation devices in a cardiothoracic intensive care unit.

    PubMed

    Chavez, Jennifer; Bortolotto, Shannon Johnson; Paulson, Martha; Huntley, Nicole; Sullivan, Breandan; Babu, Ashok

    2015-01-01

    Progressive mobility (PM) is a clinical intervention that influences complications experienced throughout critical illness. Early PM is a relevant topic in critical care practice literature and was principle to introducing a PM care guideline in an acute cardiothoracic/cardiovascular intensive care unit. A noted challenge in the cardiothoracic/cardiovascular intensive care unit is caring for acute cardiac and pulmonary failure. Often, these patients require prolonged mechanical circulatory support via extracorporeal mechanical oxygenation or a ventricular assist device. This article describes safe and effective progressive mobilization for patients experiencing MCS in a case study format. This article also highlights how a multidisciplinary clinical team supports mobility practice in specific critical care roles. Post-intensive care syndrome is composed of various health implications that occur following critical illness. Recent data suggest improved care outcomes when critically ill patients are awake and participate in active physical rehabilitation as early as clinically possible. The case studies presented indicate that mobility, to the point of ambulation, is a feasible clinical expectation when patients present with substantial acute respiratory and cardiac failure and are managed with MCS. Development of a PM guideline uses a critical appraisal of practice evidence, highlights multidisciplinary collaboration, and increases progression to ambulation. Mobility for complex patients is attainable, as demonstrated in the postguideline outcomes. The PM guideline provides structure to primary caregivers and promotes safe practices. The PM guideline facilitates an advanced level of care, promotes safe practices, champions holistic recovery, and encourages active patient involvement, goals satisfying to both patients and staff.

  1. Occurrence of serum M-protein species in Japanese patients older than 50 years based on relative mobility in cellulose acetate membrane electrophoresis.

    PubMed

    Kurihara, Y; Shiba, K; Fukumura, Y; Kobayashi, I; Kamei, S

    2000-01-01

    We investigated the occurrence of serum M-protein species in 2,007 Japanese patients older than 50 years of age. All sera samples were analyzed by cellulose acetate membrane electrophoresis. The relative mobility of an M-protein band was calculated by dividing the migration distance of M protein by that of albumin. M proteins were found to be present in 71 of 2,007 cases (3.5%). Men 80-89 years old showed the highest occurrence of M proteins, 11.0%. The relative mobility of M-protein bands, especially the band of the IgA-type M protein, increased as the patient's age advanced. The patients had higher levels of the IgG-type M protein than healthy Japanese subjects. We found that the occurrence of M-protein species in Japanese patients increases with their age. The IgG-type M protein was most frequently expressed among other types. The mobility of the M protein was greater in older patients probably because of aging-related changes in the carbohydrate chain of immunoglobulins composing an M-protein molecule.

  2. A Cytosolic Chaperone Complexes with Dynamic Membrane J-Proteins and Mobilizes a Nonenveloped Virus out of the Endoplasmic Reticulum

    PubMed Central

    Walczak, Christopher Paul; Ravindran, Madhu Sudhan; Inoue, Takamasa; Tsai, Billy

    2014-01-01

    Nonenveloped viruses undergo conformational changes that enable them to bind to, disrupt, and penetrate a biological membrane leading to successful infection. We assessed whether cytosolic factors play any role in the endoplasmic reticulum (ER) membrane penetration of the nonenveloped SV40. We find the cytosolic SGTA-Hsc70 complex interacts with the ER transmembrane J-proteins DnaJB14 (B14) and DnaJB12 (B12), two cellular factors previously implicated in SV40 infection. SGTA binds directly to SV40 and completes ER membrane penetration. During ER-to-cytosol transport of SV40, SGTA disengages from B14 and B12. Concomitant with this, SV40 triggers B14 and B12 to reorganize into discrete foci within the ER membrane. B14 must retain its ability to form foci and interact with SGTA-Hsc70 to promote SV40 infection. Our results identify a novel role for a cytosolic chaperone in the membrane penetration of a nonenveloped virus and raise the possibility that the SV40-induced foci represent cytosol entry sites. PMID:24675744

  3. Mutually unbiased product bases for multiple qudits

    SciTech Connect

    McNulty, Daniel; Pammer, Bogdan; Weigert, Stefan

    2016-03-15

    We investigate the interplay between mutual unbiasedness and product bases for multiple qudits of possibly different dimensions. A product state of such a system is shown to be mutually unbiased to a product basis only if each of its factors is mutually unbiased to all the states which occur in the corresponding factors of the product basis. This result implies both a tight limit on the number of mutually unbiased product bases which the system can support and a complete classification of mutually unbiased product bases for multiple qubits or qutrits. In addition, only maximally entangled states can be mutually unbiased to a maximal set of mutually unbiased product bases.

  4. How Do Professional Mutual Recognition Agreements Affect Higher Education? Examining Regional Policy in North America

    ERIC Educational Resources Information Center

    Sa, Creso; Gaviria, Patricia

    2011-01-01

    Professional mutual recognition agreements (MRAs) are one of the policy instruments employed in global and regional trade agreements to facilitate the mobility of skilled labour. While such agreements have been noted in the literature examining cross-border academic mobility, little is known about how they impact higher education. This paper…

  5. How Do Professional Mutual Recognition Agreements Affect Higher Education? Examining Regional Policy in North America

    ERIC Educational Resources Information Center

    Sa, Creso; Gaviria, Patricia

    2011-01-01

    Professional mutual recognition agreements (MRAs) are one of the policy instruments employed in global and regional trade agreements to facilitate the mobility of skilled labour. While such agreements have been noted in the literature examining cross-border academic mobility, little is known about how they impact higher education. This paper…

  6. Mutual Respect and Civic Education

    ERIC Educational Resources Information Center

    Bird, Colin

    2010-01-01

    Contemporary theories of civic education frequently appeal to an ideal of mutual respect in the context of ethical, ethical and religious disagreement. This paper critically examines two recently popular criticisms of this ideal. The first, coming from a postmodern direction, charges that the ideal is hypocritical in its effort to be maximally…

  7. Hospital mutual aid evacuation plan.

    PubMed

    Phillips, R

    1997-02-01

    Health care facilities need to be prepared for disasters such as floods, tornadoes and earthquakes. Rochester, NY, and its surrounding communities devised a hospital mutual aid evacuation plan in the event a disaster occurs and also to comply with the Joint Commission. This document discusses the plan's development process and also provides the end result.

  8. Mutual Respect and Civic Education

    ERIC Educational Resources Information Center

    Bird, Colin

    2010-01-01

    Contemporary theories of civic education frequently appeal to an ideal of mutual respect in the context of ethical, ethical and religious disagreement. This paper critically examines two recently popular criticisms of this ideal. The first, coming from a postmodern direction, charges that the ideal is hypocritical in its effort to be maximally…

  9. An agent based model of integrin clustering: Exploring the role of ligand clustering, integrin homo-oligomerization, integrin-ligand affinity, membrane crowdedness and ligand mobility

    NASA Astrophysics Data System (ADS)

    Jamali, Yousef; Jamali, Tahereh; Mofrad, Mohammad R. K.

    2013-07-01

    Integrins are cell-surface protein heterodimers that coordinate cellular responses to mechanochemical cues from the extracellular matrix (ECM) and stimulate the assembly of small adhesion complexes, which are the initial sites of cell-ECM adhesion. Clustering of integrins is known to mediate signaling through a variety of signal transduction pathways. Yet, the molecular mechanisms of integrin clustering are poorly understood. In this paper, we develop computational models, using agent based modeling (ABM) techniques, to explore two key underlying mechanisms of integrin clustering, namely ligand organization and integrin homo-oligomerization. Our models help to shed light on the potential roles ligand clustering and integrin homo-oligomerization may play in controlling integrin clustering. A potential mechanism for the clustering of integrin is discussed and the effects of other parameters such as integrin-ligand affinity, membrane crowdedness and ligand mobility on integrin clustering are examined.

  10. Reduced Volume Prototype Spacesuit Water Membrane Evaporator; A Next-Generation Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Makinen, Janice V.; Anchondo, Ian; Bue, Grant C.; Campbell, Colin; Colunga, Aaron

    2013-01-01

    Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the reduced volume prototype (RVP) spacesuit water membrane evaporator (SWME). The RVP SWME is the third generation of hollow fiber SWME hardware. Like its predecessors, RVP SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Major design improvements, including a 36% reduction in volume, reduced weight, and a more flight-like backpressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. The development of these evaporative cooling systems will contribute to a more robust and comprehensive AEMU PLSS.

  11. Experimental test of new theoretical models for the electrokinetic properties of biological membranes. The effect of UO/sup 2 + +/ and tetracaine on the electrophoretic mobility of bilayer membranes and human erythrocytes

    SciTech Connect

    Pasquale, L.; Winiski, A.; Oliva, C.; Vaio, G.; McLaughlin, S.

    1986-12-01

    For a large smooth particle with charges at the surface, the electrophoretic mobility is proportional to the zeta potential, which is related to the charge density by the Gouy-Chapman theory of the diffuse double layer. This classical model adequately describes the dependence of the electrophoretic mobility of phospholipid vesicles on charge density and salt concentration, but it is not applicable to most biological cells, for which new theoretical models have been developed. We tested these new models experimentally by measuring the effect of UO/sup 2 + +/ on the electrophoretic mobility of model membranes and human erythrocytes in 0.15 M NaCl at pH 5. We used UO/sup 2 + +/ for these studies because it should adsorb specifically to the bilayer surface of the erythrocyte and should not change the density of fixed charges in the glycocalyx. Our experiments demonstrate that it forms high-affinity complexes with the phosphate groups of several phospholipids in a bilayer but does not bind significantly to sialic acid residues. As observed previously, UO/sup 2 + +/ adsorbs strongly to egg phosphatidylcholine (PC) vesicles: 0.1 mM UO/sup 2 + +/ changes the zeta potential of PC vesicles from 0 to +40 mV. It also has a large effect on the electrophoretic mobility of vesicles formed from mixtures of PC and the negative phospholipid phosphatidylserine (PS): 0.1 mM UO/sup 2 + +/ changes the zeta potential of PC/PS vesicles (10 mol % PS) from -13 to +37 mV. In contrast, UO/sup 2 + +/ has only a small effect on the electrophoretic mobility of either vesicles formed from mixtures of PC and the negative ganglioside GM1 or erythrocytes: 0.1 mM UO/sup 2 + +/ changes the apparent zeta potential of PC/GM1 vesicles (17 mol % GM1) from -11 to +5 mV and the apparent zeta potential of erythrocytes from -12 to -4 mV.

  12. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean.; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Petty, Brian

    2014-01-01

    Spacesuit Water Membrane Evaporator - Baseline heat rejection technology for the Portable Life Support System of the Advanced EMU center dot Replaces sublimator in the current EMU center dot Contamination insensitive center dot Can work with Lithium Chloride Absorber Radiator in Spacesuit Evaporator Absorber Radiator (SEAR) to reject heat and reuse evaporated water The Spacesuit Water Membrane Evaporator (SWME) is being developed to replace the sublimator for future generation spacesuits. Water in LCVG absorbs body heat while circulating center dot Warm water pumped through SWME center dot SWME evaporates water vapor, while maintaining liquid water - Cools water center dot Cooled water is then recirculated through LCVG. center dot LCVG water lost due to evaporation (cooling) is replaced from feedwater The Independent TCV Manifold reduces design complexity and manufacturing difficulty of the SWME End Cap. center dot The offset motor for the new BPV reduces the volume profile of the SWME by laying the motor flat on the End Cap alongside the TCV.

  13. Nematode-bacteria mutualism: Selection within the mutualism supersedes selection outside of the mutualism.

    PubMed

    Morran, Levi T; Penley, McKenna J; Byrd, Victoria S; Meyer, Andrew J; O'Sullivan, Timothy S; Bashey, Farrah; Goodrich-Blair, Heidi; Lively, Curtis M

    2016-03-01

    The coevolution of interacting species can lead to codependent mutualists. Little is known about the effect of selection on partners within verses apart from the association. Here, we determined the effect of selection on bacteria (Xenorhabdus nematophila) both within and apart from its mutualistic partner (a nematode, Steinernema carpocapsae). In nature, the two species cooperatively infect and kill arthropods. We passaged the bacteria either together with (M+), or isolated from (M-), nematodes under two different selection regimes: random selection (S-) and selection for increased virulence against arthropod hosts (S+). We found that the isolated bacteria evolved greater virulence under selection for greater virulence (M-S+) than under random selection (M-S-). In addition, the response to selection in the isolated bacteria (M-S+) caused a breakdown of the mutualism following reintroduction to the nematode. Finally, selection for greater virulence did not alter the evolutionary trajectories of bacteria passaged within the mutualism (M+S+ = M+S-), indicating that selection for the maintenance of the mutualism was stronger than selection for increased virulence. The results show that selection on isolated mutualists can rapidly breakdown beneficial interactions between species, but that selection within a mutualism can supersede external selection, potentially generating codependence over time.

  14. Nematode-Bacteria Mutualism: Selection Within the Mutualism Supersedes Selection Outside of the Mutualism

    PubMed Central

    Morran, Levi T.; Penley, McKenna J.; Byrd, Victoria S.; Meyer, Andrew J.; O’Sullivan, Timothy S.; Bashey, Farrah; Goodrich-Blair, Heidi; Lively, Curtis M.

    2016-01-01

    The coevolution of interacting species can lead to co-dependent mutualists. Little is known about the effect of selection on partners within verses apart from the association. Here, we determined the effect of selection on bacteria (Xenorhabdus nematophila) both within and apart from its mutualistic partner (a nematode, Steinernema carpocapsae). In nature, the two species cooperatively infect and kill arthropods. We passaged the bacteria either together with (M+), or isolated from (M−), nematodes under two different selection regimes: random selection (S−) and selection for increased virulence against arthropod hosts (S+). We found that the isolated bacteria evolved greater virulence under selection for greater virulence (M−S+) than under random selection (M−S−). In addition, the response to selection in the isolated bacteria (M−S+) caused a breakdown of the mutualism following reintroduction to the nematode. Finally, selection for greater virulence did not alter the evolutionary trajectories of bacteria passaged within the mutualism (M+S+ = M+S−), indicating that selection for the maintenance of the mutualism was stronger than selection for increased virulence. The results show that selection on isolated mutualists can rapidly breakdown beneficial interactions between species, but that selection within a mutualism can supersede external selection, potentially generating co-dependence over time. PMID:26867502

  15. Measurement of spatial and temporal variation in volatile hazardous air pollutants in Tacoma, Washington, using a mobile membrane introduction mass spectrometry (MIMS) system.

    PubMed

    Davey, Nicholas G; Fitzpatrick, Cole T E; Etzkorn, Jacob M; Martinsen, Morten; Crampton, Robert S; Onstad, Gretchen D; Larson, Timothy V; Yost, Michael G; Krogh, Erik T; Gilroy, Michael; Himes, Kathy H; Saganić, Erik T; Simpson, Christopher D; Gill, Christopher G

    2014-09-19

    The objective of this study was to use membrane introduction mass spectrometry (MIMS), implemented on a mobile platform, in order to provide real-time, fine-scale, temporally and spatially resolved measurements of several hazardous air pollutants. This work is important because there is now substantial evidence that fine-scale spatial and temporal variations of air pollutant concentrations are important determinants of exposure to air pollution and adverse health outcomes. The study took place in Tacoma, WA during periods of impaired air quality in the winter and summer of 2008 and 2009. Levels of fine particles were higher in winter compared to summer, and were spatially uniform across the study area. Concentrations of vapor phase pollutants measured by membrane introduction mass spectrometry (MIMS), notably benzene and toluene, had relatively uniform spatial distributions at night, but exhibited substantial spatial variation during the day-daytime levels were up to 3-fold higher at traffic-impacted locations compared to a reference site. Although no direct side-by-side comparison was made between the MIMS system and traditional fixed site monitors, the MIMS system typically reported higher concentrations of specific VOCs, particularly benzene, ethylbenzene and naphthalene, compared to annual average concentrations obtained from SUMA canisters and gas chromatographic analysis at the fixed sites.

  16. 26 CFR 1.831-3 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Tax on insurance companies (other than life or... beginning after December 31, 1962. 1.831-3 Section 1.831-3 Internal Revenue INTERNAL REVENUE SERVICE...-3 Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

  17. Pluto-charon mutual events

    SciTech Connect

    Binzel, R.P. )

    1989-11-01

    Since 1985, planetary astronomers have been working to take advantage of a once-per-century apparent alignment between Pluto and its satellite, Charon, which has allowed mutual occultation and transit events to be observed. There events, which will cease in 1990, have permitted the first precise determinations of their individual radii, densities, and surface compositions. In addition, information on their surface albedo distributions can be obtained.

  18. Mutuality in the provision of Scottish healthcare.

    PubMed

    Howieson, Brian

    2015-11-01

    The backdrop to this article is provided by the Better Health, Better Care Action Plan (Scottish Government, 2007), Section 1 of which is entitled 'Towards a Mutual NHS'. According to Better Health, Better Care (Scottish Government, 2007: 5): 'Mutual organisations are designed to serve their members. They are designed to gather people around a common sense of purpose. They are designed to bring the organisation together in what people often call "co-production."' The aim of this article is to précis the current knowledge of mutuality in the provision of Scottish healthcare. In detail, it will: introduce the 'mutual' organisation; offer a historical perspective of mutuality; suggest why healthcare mutuality is important; and briefly, detail the differences in mutual health-care policy in England and Scotland. It is hoped that this analysis will help researchers and practitioners alike appreciate further the philosophy of mutuality in the provision of Scottish healthcare.

  19. Heterologous Regulation of Mu-Opioid (MOP) Receptor Mobility in the Membrane of SH-SY5Y Cells*

    PubMed Central

    Carayon, Kévin; Moulédous, Lionel; Combedazou, Anne; Mazères, Serge; Haanappel, Evert; Salomé, Laurence; Mollereau, Catherine

    2014-01-01

    The dynamic organization of G protein-coupled receptors in the plasma membrane is suspected of playing a role in their function. The regulation of the diffusion mode of the mu-opioid (MOP) receptor was previously shown to be agonist-specific. Here we investigate the regulation of MOP receptor diffusion by heterologous activation of other G protein-coupled receptors and characterize the dynamic properties of the MOP receptor within the heterodimer MOP/neuropeptide FF (NPFF2) receptor. The data show that the dynamics and signaling of the MOP receptor in SH-SY5Y cells are modified by the activation of α2-adrenergic and NPFF2 receptors, but not by the activation of receptors not described to interact with the opioid receptor. By combining, for the first time, fluorescence recovery after photobleaching at variable radius experiments with bimolecular fluorescence complementation, we show that the MOP/NPFF2 heterodimer adopts a specific diffusion behavior that corresponds to a mix of the dynamic properties of both MOP and NPFF2 receptors. Altogether, the data suggest that heterologous regulation is accompanied by a specific organization of receptors in the membrane. PMID:25183007

  20. Proteomic analysis reveals a FANCA-modulated neddylation pathway involved in CXCR5 membrane targeting and cell mobility.

    PubMed

    Renaudin, Xavier; Guervilly, Jean-Hugues; Aoufouchi, Said; Rosselli, Filippo

    2014-08-15

    The aim of this study was to identify novel substrates of the FANCcore complex, the inactivation of which leads to the genetic disorder Fanconi anemia, which is associated with bone marrow failure, developmental abnormalities and a predisposition to cancer. Eight FANC proteins participate in the nuclear FANCcore complex, which functions as an E3 ubiquitin-ligase that monoubiquitylates FANCD2 and FANCI in response to replicative stress. Here, we use mass spectrometry to compare proteins from FANCcore-complex-deficient cells to those of rescued control cells after treatment with hydroxyurea, an inducer of FANCD2 monoubiquitylation. FANCD2 and FANCI appear to be the only targets of the FANCcore complex. We identify other proteins that are post-translationally modified in a FANCA- or FANCC-dependent manner. The majority of these potential targets localize to the cell membrane. Finally, we demonstrate that (a) the chemokine receptor CXCR5 is neddylated; (b) FANCA but not FANCC appears to modulate CXCR5 neddylation through an unknown mechanism; (c) CXCR5 neddylation is involved in targeting the receptor to the cell membrane; and (d) CXCR5 neddylation stimulates cell migration and motility. Our work has uncovered a pathway involving FANCA in neddylation and cell motility.

  1. Influence of external chloride concentration on the kinetics of mobile charges in the cell membrane of Valonia utricularis

    PubMed Central

    Wang, Jianning; Wehner, Günter; Benz, Roland; Zimmermann, Ulrich

    1991-01-01

    Charge pulse relaxation studies were performed on cells of the giant marine alga Valonia utricularis. Two exponential voltage relaxations were recorded as found previously (Benz, R., and U. Zimmermann. 1983. Biophys. J. 43:13-26.). The parameters of the two exponential voltage decays were studied as a function of the chloride concentration in the artificial sea water. Replacement of external chloride by 2(N-morpholino)ethanesulfonate (Mes-) had a dramatic influence on the four relaxation parameters. This chloride dependence could not be satisfactorily explained by the simplified model used earlier. Accordingly, additional reaction steps had to be included in the model. Only two relaxation processes could be resolved under all experimental conditions. This means that the heterogeneous complexation reactions, kR (association), and kD (dissociation) were too fast to be resolved. Therefore a carrier model with equilibrium heterogeneous surface reactions was used to fit the experimental results. From the charge pulse data at different chloride concentrations the translocation rate constants of the free and complexed carriers, kS and kAS, through the membrane, as well as the total surface concentration of carrier systems, N0, could be evaluated. The results described here indicate that the cell membrane of Valonia utricularis contains an electrogenic transport system for chloride. PMID:19431785

  2. Biological membrane modeling with a liquid/liquid interface. Probing mobility and environment with total internal reflection excited fluorescence.

    PubMed Central

    Morrison, L E; Weber, G

    1987-01-01

    Total internal reflection of exciting light, in combination with fluorescence intensity and polarization measurements, was used to selectively study fluorescent compounds adsorbed to the interface region between two immiscible liquids. A fluorometer was constructed which provided excitation at variable angles of incidence and allowed sensitive detection of polarized fluorescence emitted from the interface. The compound 4,4'-bis-1-phenylamino-8-naphthalenesulfonate (bis-ANS) was examined at a decalin/water interface and was found to possess remarkable affinity for the interface region with the bulk of the adsorbed molecule residing in the decalin phase. The adsorbed fluorophore displayed an apparent hindered rotation in the plane of the interface with a rotational diffusion coefficient 3- to 12-fold lower than that expected for bis-ANS in solution. While other dyes examined were not found to be significantly surface active, the addition of cationic surfactant sufficed to induce adsorption of the anionic fluorophore 1-aminonaphthalene-3,6,8-trisulfonic acid. This fluoropore was found to reside in an aqueous environment when bound to the interface, and it also exhibited hindered rotation in the plane of the interface. As the concentrations of the dyes were increased, both adsorbed dyes exhibited polarization reductions consistent with excitation energy transfer. Adsorption of bis-ANS was reversed by addition of bovine serum albumin. The membrane protein cytochrome b5 was found not to bind at the decalin/water interface, indicating that interaction with lipid is required for its adherence to biological membranes. PMID:3651556

  3. N-formyl peptide receptors in human neutrophils display distinct membrane distribution and lateral mobility when labeled with agonist and antagonist

    PubMed Central

    1993-01-01

    Receptors for bacterial N-formyl peptides are instrumental for neutrophil chemotactic locomotion and activation at sites of infection. As regulatory mechanisms for signal transduction, both rapid coupling of the occupied receptor to cytoskeletal components, and receptor lateral redistribution, have been suggested (Jesaitis et al., 1986, 1989). To compare the distribution and lateral diffusion of the nonactivated and activated neutrophil N-formyl-peptide receptor, before internalization, we used a new fluorescent N-formyl-peptide receptor antagonist, tertbutyloxycarbonyl-Phe(D)-Leu-Phe(D)-Leu-Phe-OH (Boc- FLFLF, 0.1-1 microM), and the fluorescent receptor agonist formyl-Nle- Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK, 0.1-1 microM). Fluorescent Boc-FLFLF did not elicit an oxidative burst in the neutrophil at 37 degrees C, as assessed by chemiluminescence and reduction of p-nitroblue tetrazolium chloride, but competed efficiently both with formyl-methionyl-leucyl- phenylalanine (fMLF) and fnLLFnLYK. It was not internalized, as evidenced by confocal microscopy and acid elution of surface bound ligand. The lateral mobility characteristics of the neutrophil fMLF receptor were investigated with the technique of FRAP. The diffusion coefficient (D) was similar for antagonist- and agonist-labeled receptors (D approximately 5 x 10(-10) cm2/s), but the fraction of mobile receptors was significantly lower in agonist- compared to antagonist-labeled cells, approximately 40% in contrast to approximately 60%. This reduction in receptor mobile fraction was slightly counteracted, albeit not significantly, by dihydrocytochalasin B (dhcB, 5 microM). To block internalization of agonist-labeled receptors, receptor mobility measurements were done at 14 degrees C. At this temperature, confocal microscopy revealed clustering of receptors in response to agonist binding, compared to a more uniform receptor distribution in antagonist-labeled cells. The pattern of agonist- induced receptor clustering was

  4. 76 FR 36625 - Mutual Holding Company

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... Office of Thrift Supervision Mutual Holding Company AGENCY: Office of Thrift Supervision (OTS), Treasury... collection. Title of Proposal: Mutual Holding Company. OMB Number: 1550-0072. Form Numbers: MHC-1 (OTS Form... whether the applicant meets the statutory and regulatory criteria to form a mutual holding company...

  5. 76 FR 20458 - Mutual Holding Company

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-12

    ... Office of Thrift Supervision Mutual Holding Company AGENCY: Office of Thrift Supervision (OTS), Treasury... collection. Title of Proposal: Mutual Holding Company. OMB Number: 1550-0072. Form Numbers: MHC-1 (OTS Form... whether the applicant meets the statutory and regulatory criteria to form a mutual holding company...

  6. Purinergic P2Y2 receptors mediate rapid Ca(2+) mobilization, membrane hyperpolarization and nitric oxide production in human vascular endothelial cells.

    PubMed

    Raqeeb, Abdul; Sheng, Jianzhong; Ao, Ni; Braun, Andrew P

    2011-04-01

    In blood vessels, stimulation of the vascular endothelium by the Ca(2+)-mobilizing agonist ATP initiates a number of cellular events that cause relaxation of the adjacent smooth muscle layer. Although vascular endothelial cells are reported to express several subtypes of purinergic P2Y and P2X receptors, the major isoform(s) responsible for the ATP-induced generation of vasorelaxant signals in human endothelium has not been well characterized. To address this issue, ATP-evoked changes in cytosolic Ca(2+), membrane potential and acute nitric oxide production were measured in isolated human umbilical vein endothelial cells (HUVECs) and profiled using established P2X and P2Y receptor probes. Whereas selective P2X agonist (i.e. α,β-methyl ATP) and antagonists (i.e. TNP-ATP and PPADS) could neither mimic nor block the observed ATP-evoked cellular responses, the specific P2Y receptor agonist UTP functionally reproduced all the ATP-stimulated effects. Furthermore, both ATP and UTP induced intracellular Ca(2+) mobilization with comparable EC(50) values (i.e. 1-3μM). Collectively, these functional and pharmacological profiles strongly suggest that ATP acts primarily via a P2Y2 receptor sub-type in human endothelial cells. In support, P2Y2 receptor mRNA and protein were readily detected in isolated HUVECs, and siRNA-mediated knockdown of endogenous P2Y2 receptor protein significantly blunted the cytosolic Ca(2+) elevations in response to ATP and UTP, but did not affect the histamine-evoked response. In summary, these results identify the P2Y2 isoform as the major purinergic receptor in human vascular endothelial cells that mediates the cellular actions of ATP linked to vasorelaxation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Waveguide mutually pumped phase conjugators.

    PubMed

    James, S W; Youden, K E; Jeffrey, P M; Eason, R W; Chandler, P J; Zhang, L; Townsend, P D

    1993-09-20

    The operation of the bridge mutually pumped phase conjugator is reported in a planar waveguide structure in photorefractive BaTiO(3). The waveguide was fabricated by the technique of ion implantation, using 1.5-MeVH(+) ions at a dose of 10(16) ions/cm(2). An order of magnitude decrease in response time is observed in the waveguide as compared with typical values obtained in bulk crystals, probably as a result of a combination of the optical confinement within the waveguide and possible modification of the charge-transport properties induced by the implantation process.

  8. Defense mutualisms enhance plant diversification

    PubMed Central

    Weber, Marjorie G.; Agrawal, Anurag A.

    2014-01-01

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity. PMID:25349406

  9. Defense mutualisms enhance plant diversification.

    PubMed

    Weber, Marjorie G; Agrawal, Anurag A

    2014-11-18

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity.

  10. Molecular dynamics simulations and experimental studies of binding and mobility of 7-tert-butyldimethylsilyl-10-hydroxycamptothecin and its 20(S)-4-aminobutyrate ester in DMPC membranes.

    PubMed

    Xiang, Tian-Xiang; Jiang, Zhi-Qiang; Song, Lin; Anderson, Bradley D

    2006-01-01

    The enhanced permeability and retention of liposomes in solid tumors makes liposomal formulations attractive for the targeting of various antitumor agents. This study explores the binding, orientation, and dynamic properties of a potent topoisomerase I inhibitor, 7-tert-butyldimethylsilyl-10-hydroxycamptothecin (DB-67), and its 20(S)-4-aminobutyrate ester prodrug (DB-67-AB) in DMPC liposomes by molecular dynamics (MD) simulations and experimental studies. MD simulations of an all-atom and fully hydrated liquid-crystalline bilayer (2 x 36 DMPC lipids) containing single molecules of DB-67 and DB-67-AB were conducted for up to 50 ns. Membrane/water partition coefficients for DB-67 and DB-67-AB vs pH were determined by ultracentrifugation. Fluorescence spectra and/or steady-state anisotropies were measured in various solvents and in DMPC liposomes. Kinetics for the reversible DB-67 lactone ring-opening in the presence and absence of DMPC liposomes were determined by HPLC with fluorescence detection. During the entire simulation time both DB-67 and DB-67-AB were located on the bilayer membrane near the polar ester groups of DMPC. The average depth of penetration for DB-67 and DB-67-AB was similar (12.4-13.2 A) with the prodrug's protonated amino group strongly solvated by surface water and lipid phosphate groups. Binding and fluorescence experiments revealed only a modest reduction in the binding affinity upon attachment of the ionized 4-aminobutyrate group onto DB-67. The binding microenvironment polarity resembles that of a polar solvent such as EtOH and DMSO. Kinetics experiments confirmed that DB-67 lactone hydrolysis is inhibited in the presence of DMPC liposomes, consistent with the reduced exposure of its lactone ring to water, as observed in the simulations. Both bound DB-67 and bound DB-67-AB have nonrandom orientations and reduced mobility in the membrane, especially for diffusion normal to the bilayer surface, and rotational relaxation, both of which are > or

  11. Long-range mutual information and topological uncertainty principle

    NASA Astrophysics Data System (ADS)

    Jian, Chao-Ming; Kim, Isaac; Qi, Xiao-Liang

    Ordered phases in Landau paradigm can be diagnosed by a local order parameter, whereas topologically ordered phases cannot be detected in such a way. In this paper, we propose long-range mutual information (LRMI) as a unified diagnostic for both conventional long-range order and topological order. Using the LRMI, we characterize orders in n +1D gapped systems as m-membrane condensates with 0 <= m <= n-1. The familiar conventional order and 2 +1D topological orders are respectively identified as 0-membrane and 1-membrane condensates. We propose and study the topological uncertainty principle, which describes the non-commuting nature of non-local order parameters in topological orders.

  12. Explaining mutualism variation: a new evolutionary paradox?

    PubMed

    Heath, Katy D; Stinchcombe, John R

    2014-02-01

    The paradox of mutualism is typically framed as the persistence of interspecific cooperation, despite the potential advantages of cheating. Thus, mutualism research has tended to focus on stabilizing mechanisms that prevent the invasion of low-quality partners. These mechanisms alone cannot explain the persistence of variation for partner quality observed in nature, leaving a large gap in our understanding of how mutualisms evolve. Studying partner quality variation is necessary for applying genetically explicit models to predict evolution in natural populations, a necessary step for understanding the origins of mutualisms as well as their ongoing dynamics. An evolutionary genetic approach, which is focused on naturally occurring mutualist variation, can potentially synthesize the currently disconnected fields of mutualism evolution and coevolutionary genetics. We outline explanations for the maintenance of genetic variation for mutualism and suggest approaches necessary to address them.

  13. 26 CFR 1.831-1 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, and...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... mutual), mutual marine insurance companies, and mutual fire insurance companies issuing perpetual policies. 1.831-1 Section 1.831-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... insurance companies (other than life or mutual), mutual marine insurance companies, and mutual...

  14. 26 CFR 1.831-1 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, and...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... mutual), mutual marine insurance companies, and mutual fire insurance companies issuing perpetual policies. 1.831-1 Section 1.831-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY... insurance companies (other than life or mutual), mutual marine insurance companies, and mutual...

  15. Construction of bacteria-eukaryote synthetic mutualism.

    PubMed

    Kubo, Isao; Hosoda, Kazufumi; Suzuki, Shingo; Yamamoto, Kayo; Kihara, Kumiko; Mori, Kotaro; Yomo, Tetsuya

    2013-08-01

    Mutualism is ubiquitous in nature but is known to be intrinsically vulnerable with regard to both population dynamics and evolution. Synthetic ecology has indicated that it is feasible for organisms to establish novel mutualism merely through encountering each other by showing that it is feasible to construct synthetic mutualism between organisms. However, bacteria-eukaryote mutualism, which is ecologically important, has not yet been constructed. In this study, we synthetically constructed mutualism between a bacterium and a eukaryote by using two model organisms. We mixed a bacterium, Escherichia coli (a genetically engineered glutamine auxotroph), and an amoeba, Dictyostelium discoideum, in 14 sets of conditions in which each species could not grow in monoculture but potentially could grow in coculture. Under a single condition in which the bacterium and amoeba mutually compensated for the lack of required nutrients (lipoic acid and glutamine, respectively), both species grew continuously through several subcultures, essentially establishing mutualism. Our results shed light on the establishment of bacteria-eukaryote mutualism and indicate that a bacterium and eukaryote pair in nature also has a non-negligible possibility of establishing novel mutualism if the organisms are potentially mutualistic.

  16. Effect of fish oil on lateral mobility of prostaglandin F2α (FP) receptors and spatial distribution of lipid microdomains in bovine luteal cell plasma membrane in vitro.

    PubMed

    Plewes, M R; Burns, P D; Graham, P E; Hyslop, R M; Barisas, B G

    2017-01-01

    Lipid microdomains are ordered regions on the plasma membrane of cells, rich in cholesterol and sphingolipids, ranging in size from 10 to 200 nm in diameter. These lipid-ordered domains may serve as platforms to facilitate colocalization of intracellular signaling proteins during agonist-induced signal transduction. It is hypothesized that fish oil will disrupt the lipid microdomains, increasing spatial distribution of these lipid-ordered domains and lateral mobility of the prostaglandin (PG) F2α (FP) receptors in bovine luteal cells. The objectives of this study were to examine the effects of fish oil on (1) the spatial distribution of lipid microdomains, (2) lateral mobility of FP receptors, and (3) lateral mobility of FP receptors in the presence of PGF2α on the plasma membrane of bovine luteal cells in vitro. Bovine ovaries were obtained from a local abattoir and corpora lutea were digested using collagenase. In experiment 1, lipid microdomains were labeled using cholera toxin subunit B Alexa Fluor 555. Domains were detected as distinct patches on the plasma membrane of mixed luteal cells. Fish oil treatment decreased fluorescent intensity in a dose-dependent manner (P < 0.01). In experiment 2, single particle tracking was used to examine the effects of fish oil treatment on lateral mobility of FP receptors. Fish oil treatment increased microdiffusion and macrodiffusion coefficients of FP receptors as compared to control cells (P < 0.05). In addition, compartment diameters of domains were larger, and residence times were reduced for receptors in fish oil-treated cells (P < 0.05). In experiment 3, single particle tracking was used to determine the effects of PGF2α on lateral mobility of FP receptors and influence of fish oil treatment. Lateral mobility of receptors was decreased within 5 min following the addition of ligand for control cells (P < 0.05). However, lateral mobility of receptors was unaffected by addition of ligand for fish oil-treated cells

  17. 26 CFR 1.831-3 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Tax on insurance companies (other than life or... beginning after December 31, 1962. 1.831-3 Section 1.831-3 Internal Revenue INTERNAL REVENUE SERVICE... Companies § 1.831-3 Tax on insurance companies (other than life or mutual), mutual marine...

  18. 26 CFR 1.831-3 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 8 2013-04-01 2013-04-01 false Tax on insurance companies (other than life or... beginning after December 31, 1962. 1.831-3 Section 1.831-3 Internal Revenue INTERNAL REVENUE SERVICE... Companies § 1.831-3 Tax on insurance companies (other than life or mutual), mutual marine...

  19. 26 CFR 1.831-3 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 8 2012-04-01 2012-04-01 false Tax on insurance companies (other than life or... beginning after December 31, 1962. 1.831-3 Section 1.831-3 Internal Revenue INTERNAL REVENUE SERVICE... Companies § 1.831-3 Tax on insurance companies (other than life or mutual), mutual marine insurance...

  20. 26 CFR 1.831-3 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, mutual...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Tax on insurance companies (other than life or... beginning after December 31, 1962. 1.831-3 Section 1.831-3 Internal Revenue INTERNAL REVENUE SERVICE... Companies § 1.831-3 Tax on insurance companies (other than life or mutual), mutual marine insurance...

  1. Mobile membrane introduction tandem mass spectrometry for on-the-fly measurements and adaptive sampling of VOCs around oil and gas projects in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Krogh, E.; Gill, C.; Bell, R.; Davey, N.; Martinsen, M.; Thompson, A.; Simpson, I. J.; Blake, D. R.

    2012-12-01

    The release of hydrocarbons into the environment can have significant environmental and economic consequences. The evolution of smaller, more portable mass spectrometers to the field can provide spatially and temporally resolved information for rapid detection, adaptive sampling and decision support. We have deployed a mobile platform membrane introduction mass spectrometer (MIMS) for the in-field simultaneous measurement of volatile and semi-volatile organic compounds. In this work, we report instrument and data handling advances that produce geographically referenced data in real-time and preliminary data where these improvements have been combined with high precision ultra-trace VOCs analysis to adaptively sample air plumes near oil and gas operations in Alberta, Canada. We have modified a commercially available ion-trap mass spectrometer (Griffin ICX 400) with an in-house temperature controlled capillary hollow fibre polydimethylsiloxane (PDMS) polymer membrane interface and in-line permeation tube flow cell for a continuously infused internal standard. The system is powered by 24 VDC for remote operations in a moving vehicle. Software modifications include the ability to run continuous, interlaced tandem mass spectrometry (MS/MS) experiments for multiple contaminants/internal standards. All data are time and location stamped with on-board GPS and meteorological data to facilitate spatial and temporal data mapping. Tandem MS/MS scans were employed to simultaneously monitor ten volatile and semi-volatile analytes, including benzene, toluene, ethylbenzene and xylene (BTEX), reduced sulfur compounds, halogenated organics and naphthalene. Quantification was achieved by calibrating against a continuously infused deuterated internal standard (toluene-d8). Time referenced MS/MS data were correlated with positional data and processed using Labview and Matlab to produce calibrated, geographical Google Earth data-visualizations that enable adaptive sampling protocols

  2. Physiological Aspects of Communication via Mutual Gaze.

    ERIC Educational Resources Information Center

    Mazur, Allan; And Others

    1980-01-01

    Reports on various social science projects undertaken to investigate nonverbal communication. Findings indicated that mutual gaze influences physiological arousal, an actor can gaze in such a way that he or she manipulates the other person's physiology, and a subject's response to a mutual gaze is a good predictor of dominance or submission in…

  3. Economic contract theory tests models of mutualism.

    PubMed

    Weyl, E Glen; Frederickson, Megan E; Yu, Douglas W; Pierce, Naomi E

    2010-09-07

    Although mutualisms are common in all ecological communities and have played key roles in the diversification of life, our current understanding of the evolution of cooperation applies mostly to social behavior within a species. A central question is whether mutualisms persist because hosts have evolved costly punishment of cheaters. Here, we use the economic theory of employment contracts to formulate and distinguish between two mechanisms that have been proposed to prevent cheating in host-symbiont mutualisms, partner fidelity feedback (PFF) and host sanctions (HS). Under PFF, positive feedback between host fitness and symbiont fitness is sufficient to prevent cheating; in contrast, HS posits the necessity of costly punishment to maintain mutualism. A coevolutionary model of mutualism finds that HS are unlikely to evolve de novo, and published data on legume-rhizobia and yucca-moth mutualisms are consistent with PFF and not with HS. Thus, in systems considered to be textbook cases of HS, we find poor support for the theory that hosts have evolved to punish cheating symbionts; instead, we show that even horizontally transmitted mutualisms can be stabilized via PFF. PFF theory may place previously underappreciated constraints on the evolution of mutualism and explain why punishment is far from ubiquitous in nature.

  4. Economic contract theory tests models of mutualism

    PubMed Central

    Weyl, E. Glen; Frederickson, Megan E.; Yu, Douglas W.; Pierce, Naomi E.

    2010-01-01

    Although mutualisms are common in all ecological communities and have played key roles in the diversification of life, our current understanding of the evolution of cooperation applies mostly to social behavior within a species. A central question is whether mutualisms persist because hosts have evolved costly punishment of cheaters. Here, we use the economic theory of employment contracts to formulate and distinguish between two mechanisms that have been proposed to prevent cheating in host–symbiont mutualisms, partner fidelity feedback (PFF) and host sanctions (HS). Under PFF, positive feedback between host fitness and symbiont fitness is sufficient to prevent cheating; in contrast, HS posits the necessity of costly punishment to maintain mutualism. A coevolutionary model of mutualism finds that HS are unlikely to evolve de novo, and published data on legume–rhizobia and yucca–moth mutualisms are consistent with PFF and not with HS. Thus, in systems considered to be textbook cases of HS, we find poor support for the theory that hosts have evolved to punish cheating symbionts; instead, we show that even horizontally transmitted mutualisms can be stabilized via PFF. PFF theory may place previously underappreciated constraints on the evolution of mutualism and explain why punishment is far from ubiquitous in nature. PMID:20733067

  5. Promoting Mutual Help Groups Among Older Persons.

    ERIC Educational Resources Information Center

    Haber, David

    1983-01-01

    Describes several kinds of mutual help groups and two ways to initiate them: (1) through conferences, and (2) through short-term training programs. A substantial need continues for mutual help groups in an era of reduced professional and consumer resources. Research is needed to document their extensiveness, impact and longevity. (JAC)

  6. [Maintaining solidarity: is mutuality the solution?].

    PubMed

    Gevers, J K M; Ploem, M C

    2013-01-01

    Solidarity is essentially the willingness to contribute to the community and its demands, which may even involve contributing more than one is expecting to receive. Another principle is mutuality: this refers to a balance between rights and obligations or between mutual obligations. In its advisory document 'The importance of mutuality......solidarity takes work!', The Dutch Council for Public Health and Health Care underlines the importance of ensuring solidarity within the Dutch health care system, e.g. by encouraging patients to take responsibility for their own health, possibly by introducing elements of mutuality. In our contribution, we comment on the Council's advice. Although we fully agree with the overall conclusion that solidarity should be maintained within the system, we do not see how the introduction of increased mutuality will contribute to this goal.

  7. PLASMA SPHINGOSINE 1-PHOSPHATE IS A MAJOR CHEMOATTRACTANT THAT DIRECTS EGRESS OF HEMATOPOIETIC STEM PROGENITOR CELLS FROM BONE MARROW AND ITS LEVEL IN PERIPHERAL BLOOD INCREASES DURING MOBILIZATION DUE TO ACTIVATION OF COMPLEMENT CASCADE/MEMBRANE ATTACK COMPLEX

    PubMed Central

    Ratajczak, Mariusz Z.; Lee, HakMo; Wysoczynski, Marcin; Wan, Wu; Marlicz, Wojciech; Laughlin, Mary J.; Kucia, Magda; Janowska-Wieczorek, Anna; Ratajczak, Janina

    2010-01-01

    Complement cascade (CC) becomes activated and its cleavage fragments play a crucial role in the mobilization of hematopoietic stem/progenitor cells (HSPCs). Here, we sought to determine which major chemottractant present in peripheral blood (PB) is responsible for the egress of HSPCs from the BM. We noticed that normal and mobilized plasma strongly chemoattracts HSPCs in a stromal derived factor-1 (SDF-1)-independent manner because i) plasma SDF-1 level does not correlate with mobilization efficiency, ii) the chemotactic plasma gradient is not affected in the presence of AMD3100, and iii) it is resistant to denaturation by heat. Surprisingly, the observed loss of plasma chemotactic activity after charcoal stripping suggested involvement of bioactive lipids and we focused on sphingosine-1 phosphate (S1P), a known chemoattracant of HSPCs. We found that S1P i) creates in plasma a continuously present gradient for BM-residing HSPCs, ii) is at physiologically relevant concentrations a chemoattractant several magnitudes stronger than SDF-1, and iii) its plasma level increases during mobilization due to CC activation and the interaction of membrane attack complex (MAC) with erythrocytes that are a major reservoir of S1P. We conclude and propose a new paradigm that S1P is a crucial chemoattractant for BM-residing HSPCs and that CC via MAC induces release of S1P from erythrocytes for optimal egress/mobilization of HSPCs. PMID:20357827

  8. 12 CFR 575.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Mutual holding company reorganizations. 575.3... COMPANIES § 575.3 Mutual holding company reorganizations. A mutual savings association may reorganize to become a mutual holding company, or join in a mutual holding company reorganization as an...

  9. 12 CFR 239.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Mutual holding company reorganizations. 239.3... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Mutual Holding Companies § 239.3 Mutual holding company reorganizations. (a) A mutual savings association may not reorganize to become...

  10. 12 CFR 575.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Mutual holding company reorganizations. 575.3... COMPANIES § 575.3 Mutual holding company reorganizations. A mutual savings association may reorganize to become a mutual holding company, or join in a mutual holding company reorganization as an...

  11. 12 CFR 239.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Mutual holding company reorganizations. 239.3... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Mutual Holding Companies § 239.3 Mutual holding company reorganizations. (a) A mutual savings association may not reorganize to become...

  12. 12 CFR 575.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Mutual holding company reorganizations. 575.3... COMPANIES § 575.3 Mutual holding company reorganizations. A mutual savings association may reorganize to become a mutual holding company, or join in a mutual holding company reorganization as an...

  13. 12 CFR 575.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Mutual holding company reorganizations. 575.3... COMPANIES § 575.3 Mutual holding company reorganizations. A mutual savings association may reorganize to become a mutual holding company, or join in a mutual holding company reorganization as an...

  14. 12 CFR 239.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Mutual holding company reorganizations. 239.3... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Mutual Holding Companies § 239.3 Mutual holding company reorganizations. (a) A mutual savings association may not reorganize to become...

  15. 12 CFR 575.3 - Mutual holding company reorganizations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Mutual holding company reorganizations. 575.3... COMPANIES § 575.3 Mutual holding company reorganizations. A mutual savings association may reorganize to become a mutual holding company, or join in a mutual holding company reorganization as an...

  16. Mycorrhiza: A Common Form of Mutualism.

    ERIC Educational Resources Information Center

    Medve, Richard J.

    1978-01-01

    Mycorrhizae are among the most common examples of mutualism. This article discusses their structure, symbolic relationship, factors affecting formation and applying research. Questions are posed and answers suggested. (MA)

  17. Mycorrhiza: A Common Form of Mutualism.

    ERIC Educational Resources Information Center

    Medve, Richard J.

    1978-01-01

    Mycorrhizae are among the most common examples of mutualism. This article discusses their structure, symbolic relationship, factors affecting formation and applying research. Questions are posed and answers suggested. (MA)

  18. Phenological shifts and the fate of mutualisms

    PubMed Central

    Rafferty, Nicole E.; CaraDonna, Paul J.; Bronstein, Judith L.

    2014-01-01

    Climate change is altering the timing of life history events in a wide array of species, many of which are involved in mutualistic interactions. Because many mutualisms can form only if partner species are able to locate each other in time, differential phenological shifts are likely to influence their strength, duration and outcome. At the extreme, climate change-driven shifts in phenology may result in phenological mismatch: the partial or complete loss of temporal overlap of mutualistic species. We have a growing understanding of how, when, and why phenological change can alter one type of mutualism–pollination. However, as we show here, there has been a surprising lack of attention to other types of mutualism. We generate a set of predictions about the characteristics that may predispose mutualisms in general to phenological mismatches. We focus not on the consequences of such mismatches but rather on the likelihood that mismatches will develop. We explore the influence of three key characteristics of mutualism: 1) intimacy, 2) seasonality and duration, and 3) obligacy and specificity. We predict that the following characteristics of mutualism may increase the likelihood of phenological mismatch: 1) a non-symbiotic life history in which co-dispersal is absent; 2) brief, seasonal interactions; and 3) facultative, generalized interactions. We then review the limited available data in light of our a priori predictions and point to mutualisms that are more and less likely to be at risk of becoming phenologically mismatched, emphasizing the need for research on mutualisms other than plant–pollinator interactions. Future studies should explicitly focus on mutualism characteristics to determine whether and how changing phenologies will affect mutualistic interactions. PMID:25883391

  19. Direction Finding With Mutually Orthogonal Antennas

    DTIC Science & Technology

    2011-03-24

    BIB - 1 ix List of Figures Figure Page 1 - 1 : Mutually...Likelihood Results 50mm Antennas 0.5GHz, with MUTUAL COUPLING Figure C - 79 : α = 1 ° Figure C - 80: α = 10° Figure C - 81: α = 20...146: α = 10° Figure C - 147: α = 20° Figure C - 148: α = 30° Figure C - 149: α = 40° Figure C - 150: α = 50° BIB - 1 BIBLIOGRAPHY [ 1

  20. Novel insight into stem cell mobilization-plasma sphingosine-1-phosphate is a major chemoattractant that directs the egress of hematopoietic stem progenitor cells from the bone marrow and its level in peripheral blood increases during mobilization due to activation of complement cascade/membrane attack complex.

    PubMed

    Ratajczak, M Z; Lee, H; Wysoczynski, M; Wan, W; Marlicz, W; Laughlin, M J; Kucia, M; Janowska-Wieczorek, A; Ratajczak, J

    2010-05-01

    The complement cascade (CC) becomes activated and its cleavage fragments play a crucial role in the mobilization of hematopoietic stem/progenitor cells (HSPCs). Here, we sought to determine which major chemoattractant present in peripheral blood (PB) is responsible for the egress of HSPCs from the bone marrow (BM). We noticed that normal and mobilized plasma strongly chemoattracts HSPCs in a stromal-derived factor-1 (SDF-1)-independent manner because (i) plasma SDF-1 level does not correlate with mobilization efficiency; (ii) the chemotactic plasma gradient is not affected in the presence of AMD3100 and (iii) it is resistant to denaturation by heat. Surprisingly, the observed loss of plasma chemotactic activity after charcoal stripping suggested the involvement of bioactive lipids and we focused on sphingosine-1-phosphate (S1P), a known chemoattracant of HSPCs. We found that S1P (i) creates in plasma a continuously present gradient for BM-residing HSPCs; (ii) is at physiologically relevant concentrations a chemoattractant several magnitudes stronger than SDF-1 and (iii) its plasma level increases during mobilization due to CC activation and interaction of the membrane attack complex (MAC) with erythrocytes that are a major reservoir of S1P. We conclude and propose a new paradigm that S1P is a crucial chemoattractant for BM-residing HSPCs and that CC through MAC induces the release of S1P from erythrocytes for optimal egress/mobilization of HSPCs.

  1. Cadmium (II) and lead (II) transport in a polymer inclusion membrane using tributyl phosphate as mobile carrier and CuFeO(2) as a polarized photo electrode.

    PubMed

    Arous, Omar; Amara, Mourad; Trari, Mohamed; Bouguelia, Aissa; Kerdjoudj, Hacène

    2010-08-15

    In this work, a development of polymeric inclusion membranes for the cations separation is reported. The membrane was made up of cellulose triacetate (CTA) with a tributyl phosphate (TBP) incorporated into the polymer as metal ions carrier. The transport of lead (II) and cadmium (II) ions in two membrane systems polymer inclusion membrane (PIM), PIM coupled with photo-chemical electrode using TBP as carrier and 2-nitro phenyl octyl ether (NPOE) or tris ethylhexyl phosphate (TEHP) as plasticizer have been investigated. The membranes: polymer+plasticizer+carrier were synthesized and characterized by FTIR, X-ray diffraction and scanning electron microscopy (SEM). Transports of lead and cadmium have been studied using these systems and the results were compared to commercial cation exchange membrane (CRA). The obtained results showed that for Pb(2+) ion, the concentrations of the strip phase increases using synthesized membranes. The conduction band of the delafossite CuFeO(2) (-1.25 V(SCE)) yields a thermodynamically M(2+) (=Pb(2+), Cd(2+)) photo electrodeposition and speeds up the diffusion process. In all the cases, the potential of the electrode M/M(2+) in the feed compartment increases until a maximum value, reached at approximately 100 min above which it undergoes a diminution. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Mutual learning and reverse innovation–where next?

    PubMed Central

    2014-01-01

    There is a clear and evident need for mutual learning in global health systems. It is increasingly recognized that innovation needs to be sourced globally and that we need to think in terms of co-development as ideas are developed and spread from richer to poorer countries and vice versa. The Globalization and Health journal’s ongoing thematic series, “Reverse innovation in global health systems: learning from low-income countries” illustrates how mutual learning and ideas about so-called "reverse innovation" or "frugal innovation" are being developed and utilized by researchers and practitioners around the world. The knowledge emerging from the series is already catalyzing change and challenging the status quo in global health. The path to truly “global innovation flow”, although not fully established, is now well under way. Mobilization of knowledge and resources through continuous communication and awareness raising can help sustain this movement. Global health learning laboratories, where partners can support each other in generating and sharing lessons, have the potential to construct solutions for the world. At the heart of this dialogue is a focus on creating practical local solutions and, simultaneously, drawing out the lessons for the whole world. PMID:24673828

  3. Mutual learning and reverse innovation--where next?

    PubMed

    Crisp, Nigel

    2014-03-28

    There is a clear and evident need for mutual learning in global health systems. It is increasingly recognized that innovation needs to be sourced globally and that we need to think in terms of co-development as ideas are developed and spread from richer to poorer countries and vice versa. The Globalization and Health journal's ongoing thematic series, "Reverse innovation in global health systems: learning from low-income countries" illustrates how mutual learning and ideas about so-called "reverse innovation" or "frugal innovation" are being developed and utilized by researchers and practitioners around the world. The knowledge emerging from the series is already catalyzing change and challenging the status quo in global health. The path to truly "global innovation flow", although not fully established, is now well under way. Mobilization of knowledge and resources through continuous communication and awareness raising can help sustain this movement. Global health learning laboratories, where partners can support each other in generating and sharing lessons, have the potential to construct solutions for the world. At the heart of this dialogue is a focus on creating practical local solutions and, simultaneously, drawing out the lessons for the whole world.

  4. 75 FR 77048 - Mutual Savings Association Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... Office of Thrift Supervision Mutual Savings Association Advisory Committee AGENCY: Department of the... Thrift Supervision has determined that the renewal of the ] Charter of the OTS Mutual Savings Association... facing mutual savings associations. DATES: The Charter of the OTS Mutual Savings Association Advisory...

  5. 12 CFR 544.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Federal mutual savings association bylaws. 544... MUTUAL SAVINGS ASSOCIATIONS-CHARTER AND BYLAWS Bylaws § 544.5 Federal mutual savings association bylaws. (a) General. A Federal mutual savings association shall operate under bylaws that contain provisions...

  6. Integrating plant carbon dynamics with mutualism ecology.

    PubMed

    Pringle, Elizabeth G

    2016-04-01

    Plants reward microbial and animal mutualists with carbohydrates to obtain nutrients, defense, pollination, and dispersal. Under a fixed carbon budget, plants must allocate carbon to their mutualists at the expense of allocation to growth, reproduction, or storage. Such carbon trade-offs are indirectly expressed when a plant exhibits reduced growth or fecundity in the presence of its mutualist. Because carbon regulates the costs of all plant mutualisms, carbon dynamics are a common platform for integrating these costs in the face of ecological complexity and context dependence. The ecophysiology of whole-plant carbon allocation could thus elucidate the ecology and evolution of plant mutualisms. If mutualisms are costly to plants, then they must be important but frequently underestimated sinks in the terrestrial carbon cycle.

  7. Mutual Information Rate and Bounds for It

    PubMed Central

    Baptista, Murilo S.; Rubinger, Rero M.; Viana, Emilson R.; Sartorelli, José C.; Parlitz, Ulrich; Grebogi, Celso

    2012-01-01

    The amount of information exchanged per unit of time between two nodes in a dynamical network or between two data sets is a powerful concept for analysing complex systems. This quantity, known as the mutual information rate (MIR), is calculated from the mutual information, which is rigorously defined only for random systems. Moreover, the definition of mutual information is based on probabilities of significant events. This work offers a simple alternative way to calculate the MIR in dynamical (deterministic) networks or between two time series (not fully deterministic), and to calculate its upper and lower bounds without having to calculate probabilities, but rather in terms of well known and well defined quantities in dynamical systems. As possible applications of our bounds, we study the relationship between synchronisation and the exchange of information in a system of two coupled maps and in experimental networks of coupled oscillators. PMID:23112809

  8. Mutual entropy production in bipartite systems

    NASA Astrophysics Data System (ADS)

    Diana, Giovanni; Esposito, Massimiliano

    2014-04-01

    It was recently shown by Barato et al (2013 Phys. Rev. E 87 042104) that the mutual information at the trajectory level of a bipartite Markovian system is not bounded by the entropy production. In the same way as Gaspard showed (2004 J. Stat. Phys. 117 599) that the entropy production is not directly related to the Shannon entropy at the trajectory level but is in fact equal to its difference from the so-called time-reversed Shannon entropy, we show in this paper that the difference between the mutual information and its time-reversed form is equal to the mutual entropy production (MEP), i.e. the difference between the full entropy production and that of the two marginal processes. Evaluation of the MEP is in general a difficult task due to non-Markovian effects. For bipartite systems, we provide closed expressions in various limiting regimes which we verify by numerical simulations.

  9. Mutual information and spontaneous symmetry breaking

    NASA Astrophysics Data System (ADS)

    Hamma, A.; Giampaolo, S. M.; Illuminati, F.

    2016-01-01

    We show that the metastable, symmetry-breaking ground states of quantum many-body Hamiltonians have vanishing quantum mutual information between macroscopically separated regions and are thus the most classical ones among all possible quantum ground states. This statement is obvious only when the symmetry-breaking ground states are simple product states, e.g., at the factorization point. On the other hand, symmetry-breaking states are in general entangled along the entire ordered phase, and to show that they actually feature the least macroscopic correlations compared to their symmetric superpositions is highly nontrivial. We prove this result in general, by considering the quantum mutual information based on the two-Rényi entanglement entropy and using a locality result stemming from quasiadiabatic continuation. Moreover, in the paradigmatic case of the exactly solvable one-dimensional quantum X Y model, we further verify the general result by considering also the quantum mutual information based on the von Neumann entanglement entropy.

  10. Brain activity: connectivity, sparsity, and mutual information.

    PubMed

    Cassidy, Ben; Rae, Caroline; Solo, Victor

    2015-04-01

    We develop a new approach to functional brain connectivity analysis, which deals with four fundamental aspects of connectivity not previously jointly treated. These are: temporal correlation, spurious spatial correlation, sparsity, and network construction using trajectory (as opposed to marginal) Mutual Information. We call the new method Sparse Conditional Trajectory Mutual Information (SCoTMI). We demonstrate SCoTMI on simulated and real fMRI data, showing that SCoTMI gives more accurate and more repeatable detection of network links than competing network estimation methods.

  11. Conceptual Alignment: How Brains Achieve Mutual Understanding.

    PubMed

    Stolk, Arjen; Verhagen, Lennart; Toni, Ivan

    2016-03-01

    We share our thoughts with other minds, but we do not understand how. Having a common language certainly helps, but infants' and tourists' communicative success clearly illustrates that sharing thoughts does not require signals with a pre-assigned meaning. In fact, human communicators jointly build a fleeting conceptual space in which signals are a means to seek and provide evidence for mutual understanding. Recent work has started to capture the neural mechanisms supporting those fleeting conceptual alignments. The evidence suggests that communicators and addressees achieve mutual understanding by using the same computational procedures, implemented in the same neuronal substrate, and operating over temporal scales independent from the signals' occurrences.

  12. Anion exchange membrane

    DOEpatents

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  13. Competition as a mechanism structuring mutualisms

    Treesearch

    Robert J. Warren; Itamar Giladi; Mark A. Bradford

    2014-01-01

    Summary 1. Hutchinsonian niche theory posits that organisms have fundamental abiotic resource requirements from which they are limited by competition. Organisms also have fundamental biotic requirements, such as mutualists, for which they also might compete. 2. We test this idea with a widespread ant–plant mutualism. Ant-mediated seed dispersal (myrmecochory) in...

  14. Mutual Group Hypnosis: A Social Interaction Analysis.

    ERIC Educational Resources Information Center

    Sanders, Shirley

    Mutual Group Hypnosis is discussed in terms of its similarity to group dynamics in general and in terms of its similarity to a social interaction program (Role Modeling) designed to foster the expression of warmth and acceptance among group members. Hypnosis also fosters a regression to prelogical thought processes in the service of the ego. Group…

  15. Mutual Group Hypnosis: A Social Interaction Analysis.

    ERIC Educational Resources Information Center

    Sanders, Shirley

    Mutual Group Hypnosis is discussed in terms of its similarity to group dynamics in general and in terms of its similarity to a social interaction program (Role Modeling) designed to foster the expression of warmth and acceptance among group members. Hypnosis also fosters a regression to prelogical thought processes in the service of the ego. Group…

  16. Mutually unbiased bases and generalized Bell states

    SciTech Connect

    Klimov, Andrei B.; Sych, Denis; Sanchez-Soto, Luis L.; Leuchs, Gerd

    2009-05-15

    We employ a straightforward relation between mutually unbiased and Bell bases to extend the latter in terms of a direct construction for the former. We analyze in detail the properties of these generalized Bell states, showing that they constitute an appropriate tool for testing entanglement in bipartite multiqudit systems.

  17. Do Mutual Children Cement Bonds in Stepfamilies?

    ERIC Educational Resources Information Center

    Ganong, Lawrence H.; Coleman, Marilyn

    1988-01-01

    Interviewed 105 midwestern stepfamilies, 39 of whom had reproduced together. Found no significant differences between families with mutual children and those without in terms of marital adjustment, stepparent- and parent-child relationships, and stepfamily affect. It was not possible to predict which families were most likely to reproduce together…

  18. Empowering Public Welfare Workers through Mutual Support.

    ERIC Educational Resources Information Center

    Sherman, Wendy Ruth; Wenocur, Stanley

    1983-01-01

    Examines the organizational binds facing social workers concerned with the provision of services to clients in times of fiscal restraint. Suggests a mutual support group as a step toward empowerment. Workers may shift from a support group to a coalition for action as change agents within institutional settings. (JAC)

  19. Do Mutual Children Cement Bonds in Stepfamilies?

    ERIC Educational Resources Information Center

    Ganong, Lawrence H.; Coleman, Marilyn

    1988-01-01

    Interviewed 105 midwestern stepfamilies, 39 of whom had reproduced together. Found no significant differences between families with mutual children and those without in terms of marital adjustment, stepparent- and parent-child relationships, and stepfamily affect. It was not possible to predict which families were most likely to reproduce together…

  20. Mutual Coupling Compensation on Spectral-based DOA Algorithm

    NASA Astrophysics Data System (ADS)

    Sanudin, R.

    2016-11-01

    Direction of arrival (DOA) estimation using isotropic antenna arrays are commonly being implemented without considering the mutual coupling effect in between the array elements. This paper presents an analysis of DOA estimation with mutual coupling compensation using a linear antenna array. Mutual coupling effect is represented by mutual coupling coefficients and taken into account when calculating the array output. The mutual coupling compensation technique exploits a banded mutual coupling matrix to reduce the computational complexity. The banded matrix reflects the relationship between mutual coupling effect and the element spacing in an antenna array. The analysis is being carried out using the Capon algorithm, one of spectral-based DOA algorithms, for estimating the DOA of incoming signals. Computer simulations are performed to show the performance of the mutual coupling compensation technique on DOA estimation. Simulation results show that, in term of estimation resolution, the mutual coupling compensation technique manages to obtain a comparable results compared to the case without mutual coupling consideration. However, the mutual coupling compensation technique produces significant estimation error compared to the case without mutual coupling. The study concludes that the banded matrix of mutual coupling coefficients should be properly designed to improve the performance of mutual coupling compensation technique in DOA estimation.

  1. Plant invasions--the role of mutualisms.

    PubMed

    Richardson, D M; Allsopp, N; D'Antonio, C M; Milton, S J; Rejmánek, M

    2000-02-01

    Many introduced plant species rely on mutualisms in their new habitats to overcome barriers to establishment and to become naturalized and, in some cases, invasive. Mutualisms involving animal-mediated pollination and seed dispersal, and symbioses between plant roots and microbiota often facilitate invasions. The spread of many alien plants, particularly woody ones, depends on pollinator mutualisms. Most alien plants are well served by generalist pollinators (insects and birds), and pollinator limitation does not appear to be a major barrier for the spread of introduced plants (special conditions relating to Ficus and orchids are described). Seeds of many of the most notorious plant invaders are dispersed by animals, mainly birds and mammals. Our review supports the view that tightly coevolved, plant-vertebrate seed dispersal systems are extremely rare. Vertebrate-dispersed plants are generally not limited reproductively by the lack of dispersers. Most mycorrhizal plants form associations with arbuscular mycorrhizal fungi which, because of their low specificity, do not seem to play a major role in facilitating or hindering plant invasions (except possibly on remote islands such as the Galapagos which are poor in arbuscular mycorrhizal fungi). The lack of symbionts has, however, been a major barrier for many ectomycorrhizal plants, notably for Pinus spp. in parts of the southern hemisphere. The roles of nitrogen-fixing associations between legumes and rhizobia and between actinorhizal plants and Frankia spp. in promoting or hindering invasions have been virtually ignored in the invasions literature. Symbionts required to induce nitrogen fixation in many plants are extremely widespread, but intentional introductions of symbionts have altered the invasibility of many, if not most, systems. Some of the world's worst invasive alien species only invaded after the introduction of symbionts. Mutualisms in the new environment sometimes re-unite the same species that form

  2. A mutualism-parasitism system modeling host and parasite with mutualism at low density.

    PubMed

    Wang, Yuanshi; Deangelis, Donald L

    2012-04-01

    A mutualism-parasitism system of two species is considered, where mutualism is the dominant interaction when the predators (parasites) are at low density while parasitism is dominant when the predators are at high density. Our aim is to show that mutualism at low density promotes coexistence of the species and leads to high production of the prey (host). The mutualism-parasitism system presented here is a combination of the Lotka-Volterra cooperative model and Lotka-Volterra predator-prey model. By comparing dynamics of this system with those of the Lotka-Volterra predator-prey model, we present the mechanisms by which the mutualism improves the coexistence of the species and production of the prey. Then the parameter space is divided into six regions, which correspond to the four outcomes of mutualism, commensalism, predation/parasitism and neutralism, respectively. When the parameters are varied continuously among the six regions, it is shown that the interaction outcomes of the system transition smoothly among the four outcomes. By comparing the dynamics of the specific system with those of the Lotka-Volterra cooperative model, we show that the parasitism at high density promotes stability of the system. A novel aspect of this paper is the simplicity of the model, which allows rigorous and thorough analysis and transparency of the results.

  3. Correlation Between the Mobility of Inner Plasma Membrane Structure and Agglutination by Concanavalin A in Two Cell Lines of MOPC 173 Plasmocytoma Cells

    PubMed Central

    Guérin, Claudine; Zachowski, Alain; Prigent, Bernadette; Paraf, Alain; Dunia, Irène; Diawara, Marie-Aline; Benedetti, E. L.

    1974-01-01

    Both the distribution of the concanavalin A-binding sites and the rearrangement of the intramembranous particles revealed by the freeze-etching technique, have been studied by means of two variants of the same cell line issued from MOPC 173 murine plasmocytoma. One variant does not agglutinate even in presence of high lectin concentration. It has been shown that the number of binding sites and affinity are almost the same in the two variants. The clustered distribution of intramembranous particles is induced by the interaction of the concanavalin A and the cell surface only in the variant which is agglutinable. From these results it became apparent that the clustered distribution of the membrane particulate components is an acquired feature of the plasma membrane accompanying cell agglutination. Images PMID:4521044

  4. Partner manipulation stabilises a horizontally transmitted mutualism.

    PubMed

    Heil, Martin; Barajas-Barron, Alejandro; Orona-Tamayo, Domancar; Wielsch, Natalie; Svatos, Ales

    2014-02-01

    Mutualisms require protection from non-reciprocating exploiters. Pseudomyrmex workers that engage in an obligate defensive mutualism with Acacia hosts feed exclusively on the sucrose-free extrafloral nectar (EFN) that is secreted by their hosts, a behaviour linking ant energy supply directly to host performance and thus favouring reciprocating behaviour. We tested the hypothesis that Acacia hosts manipulate this digestive specialisation of their ant mutualists. Invertase (sucrose hydrolytic) activity in the ant midguts was inhibited by chitinase, a dominant EFN protein. The inhibition occurred quickly in cell-free gut liquids and in native gels and thus likely results from an enzyme-enzyme interaction. Once a freshly eclosed worker ingests EFN as the first diet available, her invertase becomes inhibited and she, thus, continues feeding on host-derived EFN. Partner manipulation acts at the phenotypic level and means that one partner actively controls the phenotype of the other partner to enhance its dependency on host-derived rewards.

  5. Hardware device binding and mutual authentication

    DOEpatents

    Hamlet, Jason R; Pierson, Lyndon G

    2014-03-04

    Detection and deterrence of device tampering and subversion by substitution may be achieved by including a cryptographic unit within a computing device for binding multiple hardware devices and mutually authenticating the devices. The cryptographic unit includes a physically unclonable function ("PUF") circuit disposed in or on the hardware device, which generates a binding PUF value. The cryptographic unit uses the binding PUF value during an enrollment phase and subsequent authentication phases. During a subsequent authentication phase, the cryptographic unit uses the binding PUF values of the multiple hardware devices to generate a challenge to send to the other device, and to verify a challenge received from the other device to mutually authenticate the hardware devices.

  6. Conditional mutual information and quantum steering

    NASA Astrophysics Data System (ADS)

    Kaur, Eneet; Wang, Xiaoting; Wilde, Mark M.

    2017-08-01

    Quantum steering has recently been formalized in the framework of a resource theory of steering, and several quantifiers have already been introduced. Here, we propose an information-theoretic quantifier for steering called intrinsic steerability, which uses conditional mutual information to measure the deviation of a given assemblage from one having a local-hidden-state model. We thus relate conditional mutual information to quantum steering and introduce monotones that satisfy certain desirable properties. The idea behind the quantifier is to suppress the correlations that can be explained by an inaccessible quantum system and then quantify the remaining intrinsic correlations. A variant of the intrinsic steerability finds operational meaning as the classical communication cost of sending the measurement choice and outcome to an eavesdropper who possesses a purifying system of the underlying bipartite quantum state that is being measured.

  7. Battery utilizing ceramic membranes

    DOEpatents

    Yahnke, Mark S.; Shlomo, Golan; Anderson, Marc A.

    1994-01-01

    A thin film battery is disclosed based on the use of ceramic membrane technology. The battery includes a pair of conductive collectors on which the materials for the anode and the cathode may be spin coated. The separator is formed of a porous metal oxide ceramic membrane impregnated with electrolyte so that electrical separation is maintained while ion mobility is also maintained. The entire battery can be made less than 10 microns thick while generating a potential in the 1 volt range.

  8. Mutual synchronization of weakly coupled gyrotrons

    SciTech Connect

    Rozental, R. M.; Glyavin, M. Yu.; Sergeev, A. S.; Zotova, I. V.; Ginzburg, N. S.

    2015-09-15

    The processes of synchronization of two weakly coupled gyrotrons are studied within the framework of non-stationary equations with non-fixed longitudinal field structure. With the allowance for a small difference of the free oscillation frequencies of the gyrotrons, we found a certain range of parameters where mutual synchronization is possible while a high electronic efficiency is remained. It is also shown that synchronization regimes can be realized even under random fluctuations of the parameters of the electron beams.

  9. Three-Ship Mutual Interference Tests

    DTIC Science & Technology

    1965-11-16

    increase beyond this event; the data before Event 500 do not show these effects. Short duration transmit-receive misalignment as observed aboard GARCIA , is...on BELKNAP and GARCIA have not been noted on McCLOY. ii 10 CONFIDENTIAL CONFIDENTIAL TRACOR, jNC - , S, Aig? Te~oS 3. CORRECTED SEA TEST LOG Complete...frequency band causing mutual influence. In this example, chart #1 shows BELKNAP and GARCIA influencing McCLOY at a higher frequency band. Sanborn

  10. Combating isolation: Building mutual mentoring networks

    NASA Astrophysics Data System (ADS)

    Cox, Anne J.

    2015-12-01

    Women physicists can often feel isolated at work. Support from a grant through the ADVANCE program of the National Science Foundation (U.S. government funding) created mutual mentoring networks aimed at combating isolation specifically for women faculty at undergraduate-only institutions. This paper will discuss the organization of one such network, what contributed to its success, some of the outcomes, and how it might be implemented in other contexts.

  11. Mutual Coupling Analysis for Conformal Microstrip Antennas.

    DTIC Science & Technology

    1984-12-01

    coated cylinder. Certain orthogonality properties of the cylindrical vector wave functions [ 15 ] are established in this chapter. The dielectric coated...forms of orthogonal properties of these vector - wave functions have previously been investigated by Stratton [ 15 ] who used a mixed domain of (p,O,X...based upon appropriate Green’s functions are employed to rigorously treat the mutual coupling of microstrip patches on 1) an infinite grounded dielectric

  12. Observations of Pluto-Charon mutual events

    SciTech Connect

    Blanco, C.; Di Martino, M.; Ferreri, W.; Osservatorio Astronomico, Turin )

    1989-07-01

    As part of the planned 'Pluto-Charon Mutual Eclipse Season Campaign', one mutual event was observed at the ESO Observatory on July 10, 1986 and seven mutual events were observed at the Serra La Nave stellar station of Catania Astrophysical Observatory from April 29 to July 21, 1987. At ESO the measurements were performed at the 61-cm Bochum telescope equipped with a photon-counting system and U, B, V, filters; at Serra La Nave the Cassegrain focus of the 91-cm reflector was equipped with a photon-counting system and B and V filters. The observed light losses and contact times do not show relevant systematic deviations from the predicted ones. An examination of the behavior of the B and V light curves gives slight indications of a different slope of the B and V light loss of the same event for a superior or an inferior event, and shows that the superior events are shallower at wavelengths longer than B. 6 refs.

  13. Herbivory eliminates fitness costs of mutualism exploiters.

    PubMed

    Simonsen, Anna K; Stinchcombe, John R

    2014-04-01

    A common empirical observation in mutualistic interactions is the persistence of variation in partner quality and, in particular, the persistence of exploitative phenotypes. For mutualisms between hosts and symbionts, most mutualism theory assumes that exploiters always impose fitness costs on their host. We exposed legume hosts to mutualistic (nitrogen-fixing) and exploitative (non-nitrogen-fixing) symbiotic rhizobia in field conditions, and manipulated the presence or absence of insect herbivory to determine if the costly fitness effects of exploitative rhizobia are context-dependent. Exploitative rhizobia predictably reduced host fitness when herbivores were excluded. However, insects caused greater damage on hosts associating with mutualistic rhizobia, as a consequence of feeding preferences related to leaf nitrogen content, resulting in the elimination of fitness costs imposed on hosts by exploitative rhizobia. Our experiment shows that herbivory is potentially an important factor in influencing the evolutionary dynamic between legumes and rhizobia. Partner choice and host sanctioning are theoretically predicted to stabilize mutualisms by reducing the frequency of exploitative symbionts. We argue that herbivore pressure may actually weaken selection on choice and sanction mechanisms, thus providing one explanation of why host-based discrimination mechanisms may not be completely effective in eliminating nonbeneficial partners.

  14. Sequence comparisons via algorithmic mutual information

    SciTech Connect

    Milosavijevic, A.

    1994-12-31

    One of the main problems in DNA and protein sequence comparisons is to decide whether observed similarity of two sequences should be explained by their relatedness or by mere presence of some shared internal structure, e.g., shared internal tandem repeats. The standard methods that are based on statistics or classical information theory can be used to discover either internal structure or mutual sequence similarity, but cannot take into account both. Consequently, currently used methods for sequence comparison employ {open_quotes}masking{close_quotes} techniques that simply eliminate sequences that exhibit internal repetitive structure prior to sequence comparisons. The {open_quotes}masking{close_quotes} approach precludes discovery of homologous sequences of moderate or low complexity, which abound at both DNA and protein levels. As a solution to this problem, we propose a general method that is based on algorithmic information theory and minimal length encoding. We show that algorithmic mutual information factors out the sequence similarity that is due to shared internal structure and thus enables discovery of truly related sequences. We extend the recently developed algorithmic significance method to show that significance depends exponentially on algorithmic mutual information.

  15. Mobile Learning Using Mobile Phones

    ERIC Educational Resources Information Center

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  16. 78 FR 26424 - Mutual Savings Association Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ... Office of the Comptroller of the Currency Mutual Savings Association Advisory Committee AGENCY: Office of... Mutual Savings Association Advisory Committee (MSAAC). DATES: A public meeting of the MSAAC will be held... savings associations, and other issues of concern to the existing mutual savings associations. On the day...

  17. 77 FR 74052 - Mutual Savings Association Advisory Committee Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-12

    ... Office of the Comptroller of the Currency Mutual Savings Association Advisory Committee Meeting AGENCY... Mutual Savings Association Advisory Committee (MSAAC or Committee). DATES: A public meeting of the MSAAC... 8:30 a.m. EST. Agenda items include a discussion of the status of the mutual savings association...

  18. 12 CFR 563.74 - Mutual capital certificates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Application form; supporting information. An application for approval of the issuance of mutual capital... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Mutual capital certificates. 563.74 Section 563...-OPERATIONS Securities and Borrowings § 563.74 Mutual capital certificates. (a) General. No savings...

  19. Mobility management in mobile IP

    NASA Astrophysics Data System (ADS)

    Medidi, Sirisha; Golshani, Forouzan

    2002-07-01

    There is an emerging interest in integrating mobile wireless communication with the Internet based on the Ipv6 technology. Many issues introduced by the mobility of users arise when such an integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current IP addresses of mobile terminals and sustaining active IP connections as mobiles move. The paper presents some architectural and mobility management options for integrating wireless access to the Internet. We then present performance results for Mobile IPv4, route optimization and Mobile IPv6.

  20. Creating a culture of mutual respect.

    PubMed

    Kaplan, Kathryn; Mestel, Pamela; Feldman, David L

    2010-04-01

    The Joint Commission mandates that hospitals seeking accreditation have a process to define and address disruptive behavior. Leaders at Maimonides Medical Center, Brooklyn, New York, took the initiative to create a code of mutual respect that not only requires respectful behavior, but also encourages sensitivity and awareness to the causes of frustration that often lead to inappropriate behavior. Steps to implementing the code included selecting code advocates, setting up a system for mediating disputes, tracking and addressing operational system issues, providing training for personnel, developing a formal accountability process, and measuring the results.

  1. Partner selection in the mycorrhizal mutualism.

    PubMed

    Werner, Gijsbert D A; Kiers, E Toby

    2015-03-01

    Partner selection in the mycorrhizal symbiosis is thought to be a key factor stabilising the mutualism. Both plant hosts and mycorrhizal fungi have been shown to preferentially allocate resources to higher quality partners. This can help maintain underground cooperation, although it is likely that different plant species vary in the spatial precision with which they can select partners. Partner selection in the mycorrhizal symbiosis is presumably context-dependent and can be mediated by factors like (relative) resource abundance and resource fluctuations, competition among mycorrhizas, arrival order and cultivation history. Such factors complicate our current understanding of the importance of partner selection and its effectiveness in stimulating mutualistic cooperation.

  2. Arithmetic, mutually unbiased bases and complementary observables

    SciTech Connect

    Sheppeard, M. D.

    2010-02-15

    Complementary observables in quantum mechanics may be viewed as Frobenius structures in a dagger monoidal category, such as the category of finite dimensional Hilbert spaces over the complex numbers. On the other hand, their properties crucially depend on the discrete Fourier transform and its associated quantum torus, requiring only the finite fields that underlie mutually unbiased bases. In axiomatic topos theory, the complex numbers are difficult to describe and should not be invoked unnecessarily. This paper surveys some fundamentals of quantum arithmetic using finite field complementary observables, with a view considering more general axiom systems.

  3. Identity theory and personality theory: mutual relevance.

    PubMed

    Stryker, Sheldon

    2007-12-01

    Some personality psychologists have found a structural symbolic interactionist frame and identity theory relevant to their work. This frame and theory, developed in sociology, are first reviewed. Emphasized in the review are a multiple identity conception of self, identities as internalized expectations derived from roles embedded in organized networks of social interaction, and a view of social structures as facilitators in bringing people into networks or constraints in keeping them out, subsequently, attention turns to a discussion of the mutual relevance of structural symbolic interactionism/identity theory and personality theory, looking to extensions of the current literature on these topics.

  4. Generalized mutual information of quantum critical chains

    NASA Astrophysics Data System (ADS)

    Alcaraz, F. C.; Rajabpour, M. A.

    2015-04-01

    We study the generalized mutual information I˜n of the ground state of different critical quantum chains. The generalized mutual information definition that we use is based on the well established concept of the Rényi divergence. We calculate this quantity numerically for several distinct quantum chains having either discrete Z (Q ) symmetries (Q -state Potts model with Q =2 ,3 ,4 and Z (Q ) parafermionic models with Q =5 ,6 ,7 ,8 and also Ashkin-Teller model with different anisotropies) or the U (1 ) continuous symmetries (Klein-Gordon field theory, X X Z and spin-1 Fateev-Zamolodchikov quantum chains with different anisotropies). For the spin chains these calculations were done by expressing the ground-state wave functions in two special bases. Our results indicate some general behavior for particular ranges of values of the parameter n that defines I˜n. For a system, with total size L and subsystem sizes ℓ and L -ℓ , the I˜n has a logarithmic leading behavior given by c/˜n4 log[L/π sin(π/ℓ L ) ] where the coefficient c˜n is linearly dependent on the central charge c of the underlying conformal field theory describing the system's critical properties.

  5. Fluorescence recovery after photobleaching measured by confocal microscopy as a tool for the analysis of vesicular lipid transport and plasma membrane mobility

    NASA Astrophysics Data System (ADS)

    Schmitz, Gerd; Goetz, Alexandra; Orso, Evelyn; Rothe, Gregor

    1998-04-01

    The vesicular transport of lipids from the endoplasmic reticulum via the Golgi apparatus affects the composition of the plasma membrane. The purpose of our study was to develop an in vitro test system for characterization of vesicular lipid transport kinetics by using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Fibroblasts from two patients homozygous for the hypercatabolic HDL deficiency syndrome Tangier disease and 4 control subjects were pulsed with the C6-NBD-ceramide for 30 minutes. Chase incubation at room temperature resulted in the metabolic accumulation of fluorescent C6-NBD-sphingolyelin and C6-NBD-glycosylceramides in the medial- and trans-Golgi region. Cells were analyzed with an inverted Leica TCS microscope. Calibration was performed through the analysis of diffusion of 50 nm microparticles embedded in media of different viscosity. An acousto optical tunable filter (AOTF) was used for the selective bleaching of the medial- and trans- Golgi region followed by analysis of the fluorescence recovery for 4 minutes. Post-bleach fluorescence recovery through the trans-Golgi-oriented transport of NBD-sphingomyelin was calculated from 2-dimensional scans. Tangier fibroblasts displayed a retarded recovery of fluorescence in the trans- Golgi region. This suggests that the vesicular transport of sphingomyelin and cholesterol is disturbed in Tangier disease confirming data from our laboratory generated with radiometabolites on whole cells. Our data suggest that FRAP analysis allows a sensitive kinetic and spatially resolved analysis of disturbances of vesicular lipid transport.

  6. Motion vision for mobile robots

    NASA Astrophysics Data System (ADS)

    Herrb, Matthieu

    The problem of using computer vision in mobile robots is dealt with. The datacube specialized cards and a parallel machine using a transputer network are studied. The tracking and localization of a three dimensional object in a sequence of images is examined, using first order prediction of the motion in the image plane and verification by a maximal clique search in the graph of mutually compatible matchings. A dynamic environment modeling module, using numerical fusion between trinocular stereovision and tracking of stereo matched primitives is presented. The integration of this perception system in the control architecture of a mobile robot is examined to achieve various functions, such as vision servo motion and environment modeling. The functional units implementing vision tasks and the data exchanged with other units are outlined. Experiments realized with the mobile robot Hilare 1.5 allowed the proposed algorithms and concepts to be validated.

  7. Influence of inhomogeneities on holographic mutual information and butterfly effect

    NASA Astrophysics Data System (ADS)

    Cai, Rong-Gen; Zeng, Xiao-Xiong; Zhang, Hai-Qing

    2017-07-01

    We study the effect of inhomogeneity, which is induced by the graviton mass in massive gravity, on the mutual information and the chaotic behavior of a 2+1-dimensional field theory from the gauge/gravity duality. When the system is near-homogeneous, the mutual information increases as the graviton mass grows. However, when the system is far from homogeneity, the mutual information decreases as the graviton mass increases. By adding the perturbations of energy into the system, we investigate the dynamical mutual information in the shock wave geometry. We find that the greater perturbations disrupt the mutual information more rapidly, which resembles the butterfly effect in chaos theory. Besides, the greater inhomogeneity reduces the dynamical mutual information more quickly just as in the static case.

  8. Mutually-antagonistic interactions in baseball networks

    NASA Astrophysics Data System (ADS)

    Saavedra, Serguei; Powers, Scott; McCotter, Trent; Porter, Mason A.; Mucha, Peter J.

    2010-03-01

    We formulate the head-to-head matchups between Major League Baseball pitchers and batters from 1954 to 2008 as a bipartite network of mutually-antagonistic interactions. We consider both the full network and single-season networks, which exhibit structural changes over time. We find interesting structure in the networks and examine their sensitivity to baseball’s rule changes. We then study a biased random walk on the matchup networks as a simple and transparent way to (1) compare the performance of players who competed under different conditions and (2) include information about which particular players a given player has faced. We find that a player’s position in the network does not correlate with his placement in the random walker ranking. However, network position does have a substantial effect on the robustness of ranking placement to changes in head-to-head matchups.

  9. Mutual information-based facial expression recognition

    NASA Astrophysics Data System (ADS)

    Hazar, Mliki; Hammami, Mohamed; Hanêne, Ben-Abdallah

    2013-12-01

    This paper introduces a novel low-computation discriminative regions representation for expression analysis task. The proposed approach relies on interesting studies in psychology which show that most of the descriptive and responsible regions for facial expression are located around some face parts. The contributions of this work lie in the proposition of new approach which supports automatic facial expression recognition based on automatic regions selection. The regions selection step aims to select the descriptive regions responsible or facial expression and was performed using Mutual Information (MI) technique. For facial feature extraction, we have applied Local Binary Patterns Pattern (LBP) on Gradient image to encode salient micro-patterns of facial expressions. Experimental studies have shown that using discriminative regions provide better results than using the whole face regions whilst reducing features vector dimension.

  10. Propagating Resource Constraints Using Mutual Exclusion Reasoning

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Sanchez, Romeo; Do, Minh B.; Clancy, Daniel (Technical Monitor)

    2001-01-01

    One of the most recent techniques for propagating resource constraints in Constraint Based scheduling is Energy Constraint. This technique focuses in precedence based scheduling, where precedence relations are taken into account rather than the absolute position of activities. Although, this particular technique proved to be efficient on discrete unary resources, it provides only loose bounds for jobs using discrete multi-capacity resources. In this paper we show how mutual exclusion reasoning can be used to propagate time bounds for activities using discrete resources. We show that our technique based on critical path analysis and mutex reasoning is just as effective on unary resources, and also shows that it is more effective on multi-capacity resources, through both examples and empirical study.

  11. Mutually unbiased bases and bound entanglement

    NASA Astrophysics Data System (ADS)

    Hiesmayr, Beatrix C.; Löffler, Wolfgang

    2014-04-01

    In this contribution we relate two different key concepts: mutually unbiased bases (MUBs) and entanglement. We provide a general toolbox for analyzing and comparing entanglement of quantum states for different dimensions and numbers of particles. In particular we focus on bound entanglement, i.e. highly mixed states which cannot be distilled by local operations and classical communications. For a certain class of states—for which the state-space forms a ‘magic’ simplex—we analyze the set of bound entangled states detected by the MUB criterion for different dimensions d and number of particles n. We find that the geometry is similar for different d and n, consequently the MUB criterion opens possibilities to investigate the typicality of positivity under partial transposition (PPT)-bound and multipartite bound entanglement more deeply and provides a simple experimentally feasible tool to detect bound entanglement.

  12. Concurrent behavior: Are the interpretations mutually exclusive?

    PubMed Central

    Lyon, David O.

    1982-01-01

    The experimental literature is replete with examples of behavior which occur concurrently with a schedule of reinforcement. These concurrent behaviors, often with similar topographies and occurring under like circumstances, may be interpreted as functionally autonomous, collateral, adjunctive, superstitious or mediating behavior. The degree to which the interaction of concurrent and schedule controlled behavior is used in the interpretation of behavior illustrated the importance of distinguishing among these interpretations by experimental procedure. The present paper reviews the characteristics of these interpretations, and discusses the experimental procedures necessary to distinguish among them. The paper concludes that the interpretations are mutually exclusive and refer to distinct behaviors, but that the distinction between any two of the interpretations requires more than one experimental procedure. PMID:22478568

  13. Receptor for advanced glycation end products - membrane type1 matrix metalloproteinase axis regulates tissue factor expression via RhoA and Rac1 activation in high-mobility group box-1 stimulated endothelial cells.

    PubMed

    Sugimoto, Koichi; Ohkawara, Hiroshi; Nakamura, Yuichi; Takuwa, Yoh; Ishibashi, Toshiyuki; Takeishi, Yasuchika

    2014-01-01

    Atherosclerosis is understood to be a blood vessel inflammation. High-mobility group box-1 (HMGB-1) plays a key role in the systemic inflammation. Tissue factor (TF) is known to lead to inflammation which promotes thrombus formation. Membrane type1 matrix metalloprotease (MT1-MMP) associates with advanced glycation endproducts (AGE) triggered-TF protein expression and phosphorylation of NF-κB. However, it is still unclear about the correlation of MT1-MMP and HMBG-1-mediated TF expression. In this study, we investigated the molecular mechanisms of TF expression in response to HMGB-1 stimulation and the involvement of MT1-MMP in endothelial cells. Pull-down assays and Western blotting revealed that HMGB-1 induced RhoA/Rac1 activation and NF-kB phosphorylation in cultured human aortic endothelial cells. HMGB-1 increased the activity of MT1-MMP, and inhibition of RAGE or MT1-MMP by siRNA suppressed HMGB-1-induced TF upregulation as well as HMGB-1-triggered RhoA/Rac1 activation and NF-kB phosphorylation. The present study showed that RAGE/MT1-MMP axis modified HMBG-1-mediated TF expression through RhoA and Rac1 activation and NF-κB phosphorylation in endothelial cells. These results suggested that MT1-MMP was involved in vascular inflammation and might be a good target for treating atherosclerosis.

  14. Membrane stabilizer

    DOEpatents

    Mingenbach, William A.

    1988-01-01

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material.

  15. Understanding the coevolutionary dynamics of mutualism with population genomics.

    PubMed

    Yoder, Jeremy B

    2016-10-01

    Decades of research on the evolution of mutualism has generated a wealth of possible ways whereby mutually beneficial interactions between species persist in spite of the apparent advantages to individuals that accept the benefits of mutualism without reciprocating - but identifying how any particular empirical system is stabilized against cheating remains challenging. Different hypothesized models of mutualism stability predict different forms of coevolutionary selection, and emerging high-throughput sequencing methods allow examination of the selective histories of mutualism genes and, thereby, the form of selection acting on those genes. Here, I review the evolutionary theory of mutualism stability and identify how differing models make contrasting predictions for the population genomic diversity and geographic differentiation of mutualism-related genes. As an example of the possibilities offered by genomic data, I analyze genes with roles in the symbiosis of Medicago truncatula and nitrogen-fixing rhizobial bacteria, the first classic mutualism in which extensive genomic resources have been developed for both partners. Medicago truncatula symbiosis genes, as a group, differ from the rest of the genome, but they vary in the form of selection indicated by their diversity and differentiation - some show signs of selection expected from roles in sanctioning noncooperative symbionts, while others show evidence of balancing selection expected from coevolution with symbiont signaling factors. I then assess the current state of development for similar resources in other mutualistic interactions and look ahead to identify ways in which modern sequencing technology can best inform our understanding of mutualists and mutualism.

  16. On the Mutual Coupling Between Circular Resonant Slots

    NASA Technical Reports Server (NTRS)

    Abou-Khousa, M. A.; Kharkovsky, S.; Zoughi, R.

    2007-01-01

    For near- and far-field microwave imaging purposes, array of circular resonant slots can be utilized to sample the electric field at a given reference plane. In general, the sensitivity of such array probes is impaired by the mutual coupling present between the radiating elements. The mutual coupling problem poses a design tradeoff between the resolution of the array and its sensitivity. In this paper, we investigate the mutual coupling between circular resonant slots in conducting ground plane both numerically and experimentally. Based on the analysis of the dominant coupling mechanism, i.e., the surface currents, various remedies to reduce the slots' mutual coupling are proposed and verified.

  17. On the Mutual Coupling between Circular Resonant Slots

    NASA Technical Reports Server (NTRS)

    Abou-Khousa, M. A.; Kharkovshy, S.; Zoughi, R.

    2007-01-01

    For near- and far-field microwave imaging purposes, array of circular resonant slots can be utilized to sample the electric field at a given reference plane. In general, the sensitivity of such an array is impaired by the existing mutual coupling between the radiating elements or in this case circular slots. The mutual coupling problem imposes a design tradeoff between the resolution of the array and the overall system sensitivity and dynamic range. In this paper, the mutual coupling between circular resonant slots in conducting ground plane is investigated both numerically and experimentally. In particular, the mutual coupling in the E- and H-plane configurations of two identical slots is studied.

  18. Mobile electric power

    SciTech Connect

    Bloomfield, V.J.; Bloomfield, D.P.; Johnson, B.Q.

    1992-01-30

    Analytic Power has proven the feasibility of a mobile electric power unit in the form of a hydride fueled ion-exchange membrane (IEM) fuel cell stack. We have over 5 years experience building and testing IEM fuel cells. The power section of a 350 watt fuel cell stack weighs 4.65 pounds based on our five cell sub-stack component weights. The composite stack structure is fabricated from two components; a unitized flow field and catalyzed membrane. The lightweight unitized flow field concept was proven in the first three months of the contract. A single unit flow field weighs 0.155 pounds and can seal to 60 psi. The single cell catalyzed Nafion membrane exceeded our performance goal of 0.6 volts at 100 ASF. Stack performance points were 0.42 volts at 113 ASF and .75 volts at 96 asf.

  19. Mobile electric power

    NASA Astrophysics Data System (ADS)

    Bloomfield, Valerie J.; Bloomfield, David P.; Johnson, Bradley Q.

    1992-01-01

    Analytic Power has proven the feasibility of a mobile electric power unit in the form of a hydride fueled ion-exchange membrane (IEM) fuel cell stack. We have over 5 years experience building and testing IEM fuel cells. The power section of a 350 watt fuel cell stack weighs 4.65 pounds based on our five cell sub-stack component weights. The composite stack structure is fabricated from two components; a unitized flow field and catalyzed membrane. The lightweight unitized flow field concept was proven in the first three months of the contract. A single unit flow field weighs 0.155 pounds and can seal to 60 psi. The single cell catalyzed Nafion membrane exceeded our performance goal of 0.6 volts at 100 ASF. Stack performance points were 0.42 volts at 113 ASF and .75 volts at 96 ASF.

  20. Mutualism exploitation: predatory drosophilid larvae sugar-trap ants and jeopardize facultative ant-plant mutualism.

    PubMed

    Vidal, Mayra C; Sendoya, Sebastian F; Oliveira, Paulo S

    2016-07-01

    An open question in the evolutionary ecology of ant-plant facultative mutualism is how other members of the associated community can affect the interaction to a point where reciprocal benefits are disrupted. While visiting Qualea grandiflora shrubs to collect sugary rewards at extrafloral nectaries, tropical savanna ants deter herbivores and reduce leaf damage. Here we show that larvae of the fly Rhinoleucophenga myrmecophaga, which develop on extrafloral nectaries, lure potentially mutualistic, nectar-feeding ants and prey on them. Foraging ants spend less time on fly-infested foliage. Field experiments showed that predation (or the threat of predation) on ants by fly larvae produces cascading effects through three trophic levels, resulting in fewer protective ants on leaves, increased numbers of chewing herbivores, and greater leaf damage. These results reveal an undocumented mode of mutualism exploitation by an opportunistic predator at a plant-provided food source, jeopardizing ant-derived protection services to the plant. Our study documents a rather unusual case of predation of adult ants by a dipteran species and demonstrates a top-down trophic cascade within a generalized ant-plant mutualism. © 2016 by the Ecological Society of America.

  1. Using Mutual Information to capture Major Concerns of Postural Control in a Tossing activity

    PubMed Central

    Gazula, Harshvardhan; Chang, Chien Chi; Lu, Ming-Lun; Hsiang, Simon M.

    2015-01-01

    Human body motion for load-tossing activity was partitioned into three phases using four critical events based on the load position viz. lift-off, closest to body, peak and release. For each phase, three objective functions values, viz. mobilization, stabilization and muscular torque utilization, used to control the motion patterns, were then calculated. We hypothesize that the relationships between different objective functions can be extracted using information theory. The kinematic data obtained with 36 treatment combinations (2 tossing distances, 2 tossing heights, 3 weights, and 3 target clearances) was used to estimate the mutual information between each pair of objective functions and construct Chow-Liu trees. Results from this research indicate that there was no dominant concern in the first two phases of the activity; however, torque utilization and mobilization were found to be important factors in the third phase of the load tossing activity. PMID:25680297

  2. Battery utilizing ceramic membranes

    DOEpatents

    Yahnke, M.S.; Shlomo, G.; Anderson, M.A.

    1994-08-30

    A thin film battery is disclosed based on the use of ceramic membrane technology. The battery includes a pair of conductive collectors on which the materials for the anode and the cathode may be spin coated. The separator is formed of a porous metal oxide ceramic membrane impregnated with electrolyte so that electrical separation is maintained while ion mobility is also maintained. The entire battery can be made less than 10 microns thick while generating a potential in the 1 volt range. 2 figs.

  3. 7 CFR 550.13 - Mutuality of interest.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Mutuality of interest. 550.13 Section 550.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT.... Mutual interest exists when both parties benefit in the same qualitative way from the objectives of...

  4. 7 CFR 550.13 - Mutuality of interest.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Mutuality of interest. 550.13 Section 550.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT.... Mutual interest exists when both parties benefit in the same qualitative way from the objectives of...

  5. 7 CFR 550.13 - Mutuality of interest.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Mutuality of interest. 550.13 Section 550.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT.... Mutual interest exists when both parties benefit in the same qualitative way from the objectives of...

  6. 7 CFR 550.13 - Mutuality of interest.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Mutuality of interest. 550.13 Section 550.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT.... Mutual interest exists when both parties benefit in the same qualitative way from the objectives of...

  7. 7 CFR 550.13 - Mutuality of interest.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Mutuality of interest. 550.13 Section 550.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT.... Mutual interest exists when both parties benefit in the same qualitative way from the objectives of the...

  8. 76 FR 35084 - Mutual to Stock Conversion Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... Office of Thrift Supervision Mutual to Stock Conversion Application AGENCY: Office of Thrift Supervision... following information collection. Title of Proposal: Mutual to Stock Conversion Application. OMB Number... proposed stock conversion. The purpose of the information collection is to provide OTS with the...

  9. 76 FR 20459 - Mutual to Stock Conversion Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-12

    ... Office of Thrift Supervision Mutual to Stock Conversion Application AGENCY: Office of Thrift Supervision... collection. Title of Proposal: Mutual to Stock Conversion Application. OMB Number: 1550-0014. Form Numbers... furnished in the application in order to determine the safety and soundness of the proposed stock...

  10. Cooperative adaptation to establishment of a synthetic bacterial mutualism.

    PubMed

    Hosoda, Kazufumi; Suzuki, Shingo; Yamauchi, Yoshinori; Shiroguchi, Yasunori; Kashiwagi, Akiko; Ono, Naoaki; Mori, Kotaro; Yomo, Tetsuya

    2011-02-16

    To understand how two organisms that have not previously been in contact can establish mutualism, it is first necessary to examine temporal changes in their phenotypes during the establishment of mutualism. Instead of tracing back the history of known, well-established, natural mutualisms, we experimentally simulated the development of mutualism using two genetically-engineered auxotrophic strains of Escherichia coli, which mimic two organisms that have never met before but later establish mutualism. In the development of this synthetic mutualism, one strain, approximately 10 hours after meeting the partner strain, started oversupplying a metabolite essential for the partner's growth, eventually leading to the successive growth of both strains. This cooperative phenotype adaptively appeared only after encountering the partner strain but before the growth of the strain itself. By transcriptome analysis, we found that the cooperative phenotype of the strain was not accompanied by the local activation of the biosynthesis and transport of the oversupplied metabolite but rather by the global activation of anabolic metabolism. This study demonstrates that an organism has the potential to adapt its phenotype after the first encounter with another organism to establish mutualism before its extinction. As diverse organisms inevitably encounter each other in nature, this potential would play an important role in the establishment of a nascent mutualism in nature.

  11. Mutuality, Self-Silencing, and Disordered Eating in College Women

    ERIC Educational Resources Information Center

    Wechsler, Lisa S.; Riggs, Shelley A.; Stabb, Sally D.; Marshall, David M.

    2006-01-01

    The current study examined patterns of association among mutuality, self-silencing, and disordered eating in an ethnically diverse sample of college women (N = 149). Partner mutuality and overall self-silencing were negatively correlated and together were associated with six disordered eating indices. All four self-silencing subscales were…

  12. 77 FR 73115 - Mutual Savings Association Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-07

    ... Office of the Comptroller of the Currency Mutual Savings Association Advisory Committee AGENCY: Office of... has determined that the renewal of the charter of the OCC Mutual Savings Association Advisory... savings associations, the regulatory changes or other steps the OCC may be able to take to ensure the...

  13. Mutuality, Self-Silencing, and Disordered Eating in College Women

    ERIC Educational Resources Information Center

    Wechsler, Lisa S.; Riggs, Shelley A.; Stabb, Sally D.; Marshall, David M.

    2006-01-01

    The current study examined patterns of association among mutuality, self-silencing, and disordered eating in an ethnically diverse sample of college women (N = 149). Partner mutuality and overall self-silencing were negatively correlated and together were associated with six disordered eating indices. All four self-silencing subscales were…

  14. Social Climate Comparison of Mutual Help and Psychotherapy Groups.

    ERIC Educational Resources Information Center

    Toro, Paul A.; Rappaport, Julian

    In recent years, mutual help groups have been formed to address problems in substance abuse, chronic physical illness, mental illness, marital disruption, and child abuse. Despite the proliferation of these groups, little research has been conducted to assess their efficacy or what happens in them. The nature of mutual help groups (N=32) was…

  15. Higher Education and Foster Grandparent Programs: Exploring Mutual Benefits

    ERIC Educational Resources Information Center

    Peacock, James R.; O'Quin, Jo Ann

    2006-01-01

    The purpose of this article is to highlight ways in which programs within institutions of higher education and Foster Grandparent Programs can interact to their mutual benefit. Given federal and state initiatives to develop linkages between institutions of higher education and community service sites, mutual benefits exist at the program level for…

  16. GENERAL: Mutual Information and Relative Entropy of Sequential Effect Algebras

    NASA Astrophysics Data System (ADS)

    Wang, Jia-Mei; Wu, Jun-De; Cho, Minhyung

    2010-08-01

    In this paper, we introduce and investigate the mutual information and relative entropy on the sequential effect algebra, we also give a comparison of these mutual information and relative entropy with the classical ones by the venn diagrams. Finally, a nice example shows that the entropies of sequential effect algebra depend extremely on the order of its sequential product.

  17. 47 CFR 90.165 - Procedures for mutually exclusive applications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Procedures for mutually exclusive applications... filing dates) as acceptable for filing. (4) Window filing group. A window filing group comprises mutually exclusive applications whose filing date is within an announced filing window. An announced filing window...

  18. Molecular insights into seed dispersal mutualisms driving plant population recruitment

    NASA Astrophysics Data System (ADS)

    García, Cristina; Grivet, Delphine

    2011-11-01

    Most plant species require mutualistic interactions with animals to fulfil their demographic cycle. In this regard frugivory (i.e., the intake of fruits by animals) enhances natural regeneration by mobilizing a large amount of seeds from source trees to deposition sites across the landscape. By doing so, frugivores move propagules, and the genotypes they harbour creating the spatial, ecological, and genetic environment under which subsequent recruitment proceeds. Recruitment patterns can be envisioned as the result of two density- and distance-dependent processes: seed dispersal and seed/seedling survival (the Janzen-Connell model). Population genetic studies add another layer of complexity for understanding the fate of dispersed propagules: the genetic relatedness among neighbouring seeds within a seed clump, a major outcome of frugivore activity, modifies their chances of germinating and surviving. Yet, we virtually ignore how the spatial distribution of maternal progenies and recruitment patterns relate with each other in frugivore-generated seed rains. Here we focus on the critical role of frugivore-mediated seed dispersal in shaping the spatial distribution of maternal progenies in the seed rain. We first examine which genetic mechanisms underlying recruitment are influenced by the spatial distribution of maternal progenies. Next, we examine those studies depicting the spatial distribution of maternal progenies in a frugivore-generated seed rain. In doing so, we briefly review the most suitable analytical approaches applied to track the contribution of fruiting trees to the seed rain based on molecular data. Then we look more specifically at the role of distinct frugivore guilds in determining maternal genetic correlations and their expected consequences for recruitment patterns. Finally we posit some general conclusions and suggest future research directions that would provide a more comprehensive understanding of the ecological and evolutionary consequences

  19. Economic game theory for mutualism and cooperation.

    PubMed

    Archetti, Marco; Scheuring, István; Hoffman, Moshe; Frederickson, Megan E; Pierce, Naomi E; Yu, Douglas W

    2011-12-01

    We review recent work at the interface of economic game theory and evolutionary biology that provides new insights into the evolution of partner choice, host sanctions, partner fidelity feedback and public goods. (1) The theory of games with asymmetrical information shows that the right incentives allow hosts to screen-out parasites and screen-in mutualists, explaining successful partner choice in the absence of signalling. Applications range from ant-plants to microbiomes. (2) Contract theory distinguishes two longstanding but weakly differentiated explanations of host response to defectors: host sanctions and partner fidelity feedback. Host traits that selectively punish misbehaving symbionts are parsimoniously interpreted as pre-adaptations. Yucca-moth and legume-rhizobia mutualisms are argued to be examples of partner fidelity feedback. (3) The theory of public goods shows that cooperation in multi-player interactions can evolve in the absence of assortment, in one-shot social dilemmas among non-kin. Applications include alarm calls in vertebrates and exoenzymes in microbes. 2011 Blackwell Publishing Ltd/CNRS.

  20. Observation of mutual neutralization in detached plasma

    NASA Astrophysics Data System (ADS)

    Akira, Tonegawa; Isao, Shirota; Ken'ichi, Yoshida; Masataka, Ono; Kazutaka, Kawamura; Tuguhiro, Watanabe; Nobuyoshi, Ohyabu; Hajime, Suzuki; Kazuo, Takayama

    2001-10-01

    Mutual neutralization in collisions between negative ions and positive ions in molecular activated recombination (MAR) has been observed in a high density magnetized sheet plasma source TPDSHEET-IV(Test Plasma produced by Directed current for SHEET plasma) device. Measurements of the negative ion density of hydrogen atom, the electron density, electron temperature, and the heat load to the target plate were carried out in hydrogen high density plasma with hydrogen gas puff. A cylindrical probe made of tungsten ( 0.4 x 2 cm) was used to measure the spatial profiles of H- by a probe-assisted laser photodetachment The Balmer spectra of visible light emission from hydrogen or helium atoms were detected in front of the target plate. A small amount of secondary hydrogen gas puffing into a hydrogen plasma reduced strongly the heat flux to the target and increased rapidly the density of negative ions of hydrogen atom in the circumference of the plasma, while the conventional radiative and three-body recombination processes were disappeared. These results can be well explained by taking the charge exchange recombination of MAR in the detached plasma into account.

  1. Quantum mutual information along unitary orbits

    NASA Astrophysics Data System (ADS)

    Jevtic, Sania; Jennings, David; Rudolph, Terry

    2012-05-01

    Motivated by thermodynamic considerations, we analyze the variation of the quantum mutual information on a unitary orbit of a bipartite system's state with and without global constraints such as energy conservation. We solve the full optimization problem for the smallest system of two qubits and explore thoroughly the effect of unitary operations on the space of reduced-state spectra. We then provide applications of these ideas to physical processes within closed quantum systems such as a generalized collision model approach to thermal equilibrium and a global Maxwell demon playing tricks on local observers. For higher dimensions, the maximization of correlations is relatively straightforward for equal-sized subsystems, however their minimization displays nontrivial structures. We characterize a set of separable states in which the minimally correlated state resides: a collection of classically correlated states admitting a particular “Young tableau” form. Furthermore, a partial order exists on this set with respect to individual marginal entropies, and the presence of a “see-saw effect” for these entropies forces a finer analysis to determine the optimal tableau.

  2. Mutualism between tree shrews and pitcher plants

    PubMed Central

    Moran, Jonathan A; Chin, Lijin

    2010-01-01

    Three species of Nepenthes pitcher plants from Borneo engage in a mutualistic interaction with mountain tree shrews, the basis of which is the exchange of nutritional resources. The plants produce modified “toilet pitchers” that produce copious amounts of exudates, the latter serving as a food source for tree shrews. The exudates are only accessible to the tree shrews when they position their hindquarters over the pitcher orifice. Tree shrews mark valuable resources with feces and regularly defecate into the pitchers when they visit them to feed. Feces represent a valuable source of nitrogen for these Nepenthes species, but there are many facets of the mutualism that are yet to be investigated. These include, but are not limited to, seasonal variation in exudate production rates by the plants, behavioral ecology of visiting tree shrews and the mechanism by which the plants signal to tree shrews that their pitchers represent a food source. Further research into this extraordinary animal-plant interaction is required to gain a better understanding of the benefits to the participating species. PMID:20861680

  3. Genetic drift opposes mutualism during spatial population expansion

    PubMed Central

    Müller, Melanie J. I.; Neugeboren, Beverly I.; Nelson, David R.; Murray, Andrew W.

    2014-01-01

    Mutualistic interactions benefit both partners, promoting coexistence and genetic diversity. Spatial structure can promote cooperation, but spatial expansions may also make it hard for mutualistic partners to stay together, because genetic drift at the expansion front creates regions of low genetic and species diversity. To explore the antagonism between mutualism and genetic drift, we grew cross-feeding strains of the budding yeast Saccharomyces cerevisiae on agar surfaces as a model for mutualists undergoing spatial expansions. By supplying varying amounts of the exchanged nutrients, we tuned strength and symmetry of the mutualistic interaction. Strong mutualism suppresses genetic demixing during spatial expansions and thereby maintains diversity, but weak or asymmetric mutualism is overwhelmed by genetic drift even when mutualism is still beneficial, slowing growth and reducing diversity. Theoretical modeling using experimentally measured parameters predicts the size of demixed regions and how strong mutualism must be to survive a spatial expansion. PMID:24395776

  4. Genetic drift opposes mutualism during spatial population expansion.

    PubMed

    Müller, Melanie J I; Neugeboren, Beverly I; Nelson, David R; Murray, Andrew W

    2014-01-21

    Mutualistic interactions benefit both partners, promoting coexistence and genetic diversity. Spatial structure can promote cooperation, but spatial expansions may also make it hard for mutualistic partners to stay together, because genetic drift at the expansion front creates regions of low genetic and species diversity. To explore the antagonism between mutualism and genetic drift, we grew cross-feeding strains of the budding yeast Saccharomyces cerevisiae on agar surfaces as a model for mutualists undergoing spatial expansions. By supplying varying amounts of the exchanged nutrients, we tuned strength and symmetry of the mutualistic interaction. Strong mutualism suppresses genetic demixing during spatial expansions and thereby maintains diversity, but weak or asymmetric mutualism is overwhelmed by genetic drift even when mutualism is still beneficial, slowing growth and reducing diversity. Theoretical modeling using experimentally measured parameters predicts the size of demixed regions and how strong mutualism must be to survive a spatial expansion.

  5. Exploratory study of the impacts of Mutual Health Organizations on social dynamics in Benin.

    PubMed

    Ridde, Valery; Haddad, Slim; Yacoubou, Moussa; Yacoubou, Ismaelou

    2010-08-01

    The primary aim of Mutual Health Organizations (MHOs) is the financial protection of their members. However, given their community-based, participative and voluntary nature, it is conceivable that MHOs, as social organizations, would affect social dynamics. In an exploratory study in Benin, we studied social dynamics related to mutual aid, relationships of trust, and empowerment. Four MHOs, as contrasted cases, were selected from among the 11 in the region. Focus groups (n = 20) and individual interviews (n = 29) were conducted with members, non-members, and elected leaders of the four MHOs, and with professionals from the health facilities concerned. We carried out a qualitative thematic analysis of the content. Mutual aid practices, which pre-date MHOs, can be mobilized to promote MHO membership. Mutual aid practices are based on relationships of trust. The primary reason for joining an MHO is to improve financial accessibility to health services. Non-members see that members have a strong sense of empowerment in this regard, based on a high level of trust in MHOs and their elected leaders, even if their trust in health professionals is not as strong. Non-members share these feelings of confidence in MHOs and their leadership, although they trust health professionals somewhat less than do the members. The MHOs' low penetration rate therefore cannot be explained by lack of trust, as this study shows that, even with some distrust of the professionals, the overall level of trust in MHOs is high and MHOs and their leaders function as intermediaries with health professionals. Other explanatory factors are the lack of information available to villagers and, most especially, the problems they face in being able to pay the MHO premiums. Copyright 2010 Elsevier Ltd. All rights reserved.

  6. The Central Symbiosis of Molecular Biology: Molecules in Mutualism.

    PubMed

    Lanier, Kathryn A; Petrov, Anton S; Williams, Loren Dean

    2017-08-07

    As illustrated by the mitochondrion and the eukaryotic cell, little in biology makes sense except in light of mutualism. Mutualisms are persistent, intimate, and reciprocal exchanges; an organism proficient in obtaining certain benefits confers those on a partner, which reciprocates by conferring different benefits. Mutualisms (i) increase fitness, (ii) inspire robustness, (iii) are resilient and resistant to change, (iv) sponsor co-evolution, (v) foster innovation, and (vi) involve partners that are distantly related with contrasting yet complementary proficiencies. Previous to this work, mutualisms were understood to operate on levels of cells, organisms, ecosystems, and even societies and economies. Here, the concepts of mutualism are extended to molecules and are seen to apply to the relationship between RNA and protein. Polynucleotide and polypeptide are Molecules in Mutualism. RNA synthesizes protein in the ribosome and protein synthesizes RNA in polymerases. RNA and protein are codependent, and trade proficiencies. Protein has proficiency in folding into complex three-dimensional states, contributing enzymes, fibers, adhesives, pumps, pores, switches, and receptors. RNA has proficiency in direct molecular recognition, achieved by complementary base pairing interactions, which allow it to maintain, record, and transduce information. The large phylogenetic distance that characterizes partnerships in organismal mutualism has close analogy with large distance in chemical space between RNA and protein. The RNA backbone is anionic and self-repulsive and cannot form hydrophobic structural cores. The protein backbone is neutral and cohesive and commonly forms hydrophobic cores. Molecules in Mutualism extends beyond RNA and protein. A cell is a consortium of molecules in which nucleic acids, proteins, polysaccharides, phospholipids, and other molecules form a mutualism consortium that drives metabolism and replication. Analogies are found in systems such as

  7. Membrane stabilizer

    DOEpatents

    Mingenbach, W.A.

    1988-02-09

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

  8. Mutual Information Between GPS Measurements and Earthquakes

    NASA Astrophysics Data System (ADS)

    Wang, T.; Bebbington, M. S.

    2009-12-01

    Prior to the wide deployment of Continuous GPS stations in the early 1990s, there were a number of well-documented deformation rate changes observed before large earthquakes. GPS measurements provide the opportunity for systematic investigation of pre-, co- and post-seismic deformation anomalies, but contain much noise that needs to be filtered out of the observations. Assuming the existence of an earthquake cycle (for example, mainshock--aftershock--quiescence--precursory seismicity), a hidden Markov model (HMM) provides a natural framework for analyzing the observed GPS data. For two case studies of a) deep earthquakes in the central North Island, New Zealand, and b) shallow earthquakes in Southern California, an HMM fitted to the trend ranges of the GPS measurements can classify the deformation data into different patterns which form proxies for states of the earthquake cycle. Mutual information can be used to examine whether there is any relation between these patterns, in particular the Viterbi path, and subsequent (or previous) earthquakes. One class of GPS movements (identified by the HMM as having the largest range of deformation rate changes) appears to have some precursory character for earthquakes with minimum magnitude 5.1 (central North Island, New Zealand, 26 earthquakes in 1747 days) and 4.5 (Southern California, 50 earthquakes in 3815 days). We define a ``Time of Increased Probability'' (TIP) as being a 10-day interval (central North Island, New Zealand) or a 20-day interval (Southern California) following entry (as identified by the Viterbi algorithm) to the `precursory' hidden state, and examine the performance of this in probabilistically forecasting subsequent earthquakes.

  9. Quantum Conditional Mutual Information, Reconstructed States, and State Redistribution.

    PubMed

    Brandão, Fernando G S L; Harrow, Aram W; Oppenheim, Jonathan; Strelchuk, Sergii

    2015-07-31

    We give two strengthenings of an inequality for the quantum conditional mutual information of a tripartite quantum state recently proved by Fawzi and Renner, connecting it with the ability to reconstruct the state from its bipartite reductions. Namely, we show that the conditional mutual information is an upper bound on the regularized relative entropy distance between the quantum state and its reconstructed version. It is also an upper bound for the measured relative entropy distance of the state to its reconstructed version. The main ingredient of the proof is the fact that the conditional mutual information is the optimal quantum communication rate in the task of state redistribution.

  10. Spatial Mutual Information Based Hyperspectral Band Selection for Classification

    PubMed Central

    2015-01-01

    The amount of information involved in hyperspectral imaging is large. Hyperspectral band selection is a popular method for reducing dimensionality. Several information based measures such as mutual information have been proposed to reduce information redundancy among spectral bands. Unfortunately, mutual information does not take into account the spatial dependency between adjacent pixels in images thus reducing its robustness as a similarity measure. In this paper, we propose a new band selection method based on spatial mutual information. As validation criteria, a supervised classification method using support vector machine (SVM) is used. Experimental results of the classification of hyperspectral datasets show that the proposed method can achieve more accurate results. PMID:25918742

  11. Entanglement patterns in mutually unbiased basis sets

    SciTech Connect

    Lawrence, Jay

    2011-08-15

    A few simply stated rules govern the entanglement patterns that can occur in mutually unbiased basis sets (MUBs) and constrain the combinations of such patterns that can coexist in full complements of MUBs. We consider Hilbert spaces of prime power dimensions (D=p{sup N}), as realized by systems of N prime-state particles, where full complements of D+1 MUBs are known to exist, and we assume only that MUBs are eigenbases of generalized Pauli operators, without using any particular construction. The general rules include the following: (1) In any MUB, a given particle appears either in a pure state or totally entangled and (2) in any full MUB complement, each particle is pure in (p+1) bases (not necessarily the same ones) and totally entangled in the remaining (p{sup N}-p). It follows that the maximum number of product bases is p+1 and, when this number is realized, all remaining (p{sup N}-p) bases in the complement are characterized by the total entanglement of every particle. This ''standard distribution'' is inescapable for two-particle systems (of any p), where only product and generalized Bell bases are admissible MUB types. This and the following results generalize previous results for qubits [Phys. Rev. A 65. 032320 (2002); Phys. Rev. A 72, 062310 (2005)] and qutrits [Phys. Rev. A 70, 012302 (2004)], drawing particularly upon [Phys. Rev. A 72, 062310 (2005)]. With three particles there are three MUB types, and these may be combined in (p+2) different ways to form full complements. With N=4, there are 6 MUB types for p=2, but new MUB types become possible with larger p, and these are essential to realizing full complements. With this example, we argue that new MUB types that show new entanglement patterns should enter with every step in N and, also, when N is a prime plus 1, at a critical p value, p=N-1. Such MUBs should play critical roles in filling complements.

  12. MreB-Dependent Organization of the E. coli Cytoplasmic Membrane Controls Membrane Protein Diffusion.

    PubMed

    Oswald, Felix; Varadarajan, Aravindan; Lill, Holger; Peterman, Erwin J G; Bollen, Yves J M

    2016-03-08

    The functional organization of prokaryotic cell membranes, which is essential for many cellular processes, has been challenging to analyze due to the small size and nonflat geometry of bacterial cells. Here, we use single-molecule fluorescence microscopy and three-dimensional quantitative analyses in live Escherichia coli to demonstrate that its cytoplasmic membrane contains microdomains with distinct physical properties. We show that the stability of these microdomains depends on the integrity of the MreB cytoskeletal network underneath the membrane. We explore how the interplay between cytoskeleton and membrane affects trans-membrane protein (TMP) diffusion and reveal that the mobility of the TMPs tested is subdiffusive, most likely caused by confinement of TMP mobility by the submembranous MreB network. Our findings demonstrate that the dynamic architecture of prokaryotic cell membranes is controlled by the MreB cytoskeleton and regulates the mobility of TMPs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Seed storage oil mobilization.

    PubMed

    Graham, Ian A

    2008-01-01

    Storage oil mobilization starts with the onset of seed germination. Oil bodies packed with triacylglycerol (TAG) exist in close proximity with glyoxysomes, the single membrane-bound organelles that house most of the biochemical machinery required to convert fatty acids derived from TAG to 4-carbon compounds. The 4-carbon compounds in turn are converted to soluble sugars that are used to fuel seedling growth. Biochemical analysis over the last 50 years has identified the main pathways involved in this process, including beta-oxidation, the glyoxylate cycle, and gluconeogenesis. In the last few years molecular genetic dissection of the overall process in the model oilseed species Arabidopsis has provided new insight into its complexity, particularly with respect to the specific role played by individual enzymatic steps and the subcellular compartmentalization of the glyoxylate cycle. Both abscisic acid (ABA) and sugars inhibit storage oil mobilization and a substantial degree of the control appears to operate at the transcriptional level.

  14. Public-channel cryptography based on mutual chaos pass filters.

    PubMed

    Klein, Einat; Gross, Noam; Kopelowitz, Evi; Rosenbluh, Michael; Khaykovich, Lev; Kinzel, Wolfgang; Kanter, Ido

    2006-10-01

    We study the mutual coupling of chaotic lasers and observe both experimentally and in numeric simulations that there exists a regime of parameters for which two mutually coupled chaotic lasers establish isochronal synchronization, while a third laser coupled unidirectionally to one of the pair does not synchronize. We then propose a cryptographic scheme, based on the advantage of mutual coupling over unidirectional coupling, where all the parameters of the system are public knowledge. We numerically demonstrate that in such a scheme the two communicating lasers can add a message signal (compressed binary message) to the transmitted coupling signal and recover the message in both directions with high fidelity by using a mutual chaos pass filter procedure. An attacker, however, fails to recover an errorless message even if he amplifies the coupling signal.

  15. 47 CFR 101.45 - Mutually exclusive applications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Applications and Licenses Processing of Applications § 101.45 Mutually... fixed point-to-point microwave applications for authorization under this part will be entitled to...

  16. 47 CFR 101.45 - Mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Applications and Licenses Processing of Applications § 101.45 Mutually... fixed point-to-point microwave applications for authorization under this part will be entitled to...

  17. Nonlinear pattern analysis of ventricular premature beats by mutual information

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Yokoshima, T.; Kishida, H.; Hayakawa, H.; Cohen, R. J.

    1997-01-01

    The frequency of ventricular premature beats (VPBs) has been related to the risk of mortality. However, little is known about the temporal pattern of occurrence of VPBs and its relationship to autonomic activity. Hence, we applied a general correlation measure, mutual information, to quantify how VPBs are generated over time. We also used mutual information to determine the correlation between VPB production and heart rate in order to evaluate effects of autonomic activity on VPB production. We examined twenty subjects with more than 3000 VPBs/day and simulated random time series of VPB occurrence. We found that mutual information values could be used to characterize quantitatively the temporal patterns of VPB generation. Our data suggest that VPB production is not random and VPBs generated with a higher value of mutual information may be more greatly affected by autonomic activity.

  18. Parasponia: a novel system for studying mutualism stability.

    PubMed

    Behm, Jocelyn E; Geurts, Rene; Kiers, E Toby

    2014-12-01

    Understanding how mutualistic interactions are stabilized in the presence of cheaters is a major question in evolutionary biology. The legume-rhizobia mutualism has become a model system for studying how plants control cheating partners. However, the generality and evolutionary origins of these control mechanisms are intensely debated. In this Opinion article, we argue that a novel system--the Parasponia-rhizobia mutualism--will significantly advance research in mutualism stability. Parasponia is the only non-legume lineage to have evolved a rhizobial symbiosis, which provides an evolutionary replicate to test how rhizobial exploitation is controlled. Evidence also suggests that this symbiosis is young. This allows studies at an earlier evolutionary stage in mutualisms, so the origin of control mechanisms can be better understood.

  19. 1. PHOTOCOPY OF ASSOCIATED MUTUAL FIRE INSURANCE MAP 1906: ...

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

    1. PHOTOCOPY OF ASSOCIATED MUTUAL FIRE INSURANCE MAP - 1906: ROGERS LOCOMOTIVE WORKS, PATERSON, N.J. (4x5 NEGATIVE) - Rogers Locomotive & Machine Works, Spruce & Market Streets, Paterson, Passaic County, NJ

  20. Mutual intentions as a causal framework for social groups.

    PubMed

    Noyes, Alexander; Dunham, Yarrow

    2017-02-24

    Children's early emerging intuitive theories are specialized for different conceptual domains. Recently attention has turned to children's concepts of social groups, finding that children believe that many social groups mark uniquely social information such as allegiances and obligations. But another critical component of intuitive theories, the causal beliefs that underlie category membership, has received less attention. We propose that children believe membership in these groups is constituted by mutual intentions: i.e., all group members (including the individual) intend for an individual to be a member and all group members (including the individual) have common knowledge of these intentions. Children in a broad age range (4-9) applied a mutual-intentional framework to newly encountered social groups early in development (Experiment 1, 2, 4). Further, they deploy this mutual-intentional framework selectively, withholding it from essentialized social categories such as gender (Experiment 3). Mutual intentionality appears to be a vital aspect of children's naïve sociology.

  1. 47 CFR 24.831 - Mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 24.831 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PERSONAL COMMUNICATIONS SERVICES Interim Application, Licensing, and Processing Rules for Broadband PCS...) and are timely filed for the same frequency block. (b) Mutually exclusive applications filed on Form...

  2. 47 CFR 24.431 - Mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 24.431 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PERSONAL COMMUNICATIONS SERVICES Interim Application, Licensing and Processing Rules for Narrowband PCS... conflict. (b) Mutually exclusive applications filed on Form 175 for the initial provision of narrowband PCS...

  3. 47 CFR 27.321 - Mutually exclusive applications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Application, Licensing, and Processing Rules for WCS § 27.321... Commission's rules governing the Wireless Communications Services involved. The Commission uses the general procedures in this section for processing mutually exclusive applications in the Wireless...

  4. 47 CFR 27.321 - Mutually exclusive applications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Application, Licensing, and Processing Rules for WCS § 27.321... Commission's rules governing the Wireless Communications Services involved. The Commission uses the general procedures in this section for processing mutually exclusive applications in the Wireless...

  5. 47 CFR 27.321 - Mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Application, Licensing, and Processing Rules for WCS § 27.321... Commission's rules governing the Wireless Communications Services involved. The Commission uses the general procedures in this section for processing mutually exclusive applications in the Wireless...

  6. 47 CFR 27.321 - Mutually exclusive applications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Application, Licensing, and Processing Rules for WCS § 27.321... Commission's rules governing the Wireless Communications Services involved. The Commission uses the general procedures in this section for processing mutually exclusive applications in the Wireless...

  7. 47 CFR 27.321 - Mutually exclusive applications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Application, Licensing, and Processing Rules for WCS § 27.321... Commission's rules governing the Wireless Communications Services involved. The Commission uses the general procedures in this section for processing mutually exclusive applications in the Wireless...

  8. Nonlinear pattern analysis of ventricular premature beats by mutual information

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Yokoshima, T.; Kishida, H.; Hayakawa, H.; Cohen, R. J.

    1997-01-01

    The frequency of ventricular premature beats (VPBs) has been related to the risk of mortality. However, little is known about the temporal pattern of occurrence of VPBs and its relationship to autonomic activity. Hence, we applied a general correlation measure, mutual information, to quantify how VPBs are generated over time. We also used mutual information to determine the correlation between VPB production and heart rate in order to evaluate effects of autonomic activity on VPB production. We examined twenty subjects with more than 3000 VPBs/day and simulated random time series of VPB occurrence. We found that mutual information values could be used to characterize quantitatively the temporal patterns of VPB generation. Our data suggest that VPB production is not random and VPBs generated with a higher value of mutual information may be more greatly affected by autonomic activity.

  9. Viscosity and mutual diffusion in strongly asymmetric plasma mixtures

    SciTech Connect

    Bastea, S

    2004-09-07

    The authors present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric two-component plasma (TCP). They compare the results with available theoretical models previously tested for much smaller asymmetries. for the case of viscosity they propose a new predictive framework based on the linear mixing rule, while for mutual diffusion they point out some consistency problems of widely used Boltzmann equation based models.

  10. Viscosity and mutual diffusion in strongly asymmetric binary ionic mixtures

    SciTech Connect

    Bastea, Sorin

    2005-05-01

    We present molecular dynamics simulation results for the viscosity and mutual diffusion constant of a strongly asymmetric binary ionic mixture. We compare the results with available theoretical models previously tested for much smaller asymmetries. For the case of viscosity we propose a predictive framework based on the linear mixing rule, while for mutual diffusion we discuss some consistency problems of widely used Boltzmann-equation-based models.

  11. Mutual impedance of nonplanar-skew sinusoidal dipoles

    NASA Technical Reports Server (NTRS)

    Richmond, J. H.; Geary, N. H.

    1975-01-01

    The mutual impedance expressions for parallel dipoles in terms of sine-integrals and cosine-integrals have been published by King (1957). The investigation reported provides analogous expressions for nonparallel dipoles. The expressions presented are most useful when the monopoles are close together. The theory of moment methods shows an approach for employing the mutual impedance of filamentary sinusoidal dipoles to calculate the impedance and scattering properties of straight and bent wires with small but finite diameter.

  12. Quantum process reconstruction based on mutually unbiased basis

    SciTech Connect

    Fernandez-Perez, A.; Saavedra, C.; Klimov, A. B.

    2011-05-15

    We study a quantum process reconstruction based on the use of mutually unbiased projectors (MUB projectors) as input states for a D-dimensional quantum system, with D being a power of a prime number. This approach connects the results of quantum-state tomography using mutually unbiased bases with the coefficients of a quantum process, expanded in terms of MUB projectors. We also study the performance of the reconstruction scheme against random errors when measuring probabilities at the MUB projectors.

  13. Non-rigid registration using higher-order mutual information

    NASA Astrophysics Data System (ADS)

    Rueckert, D.; Clarkson, M. J.; Hill, D. L. G.; Hawkes, D. J.

    2000-03-01

    Non-rigid registration of multi-modality images is an important tool for assessing temporal and structural changesbetween images. For rigid registration, voxel similarity measures like mutual information have been shown to alignimages from different modalities accurately and robustly. For non-rigid registration, mutual information can besensitive to local variations of intensity which in MR images may be caused by RF inhomogeneity. The reasonfor the sensitivity of mutual information towards intensity variations stems from the fact that mutual informationignores any spatial information. In this paper we propose an extension of the mutual information framework whichincorporates spatial information about higher-order image structure into the registration process and has the potentialto improve the accuracy and robustness of non-rigid registration in the presence of intensity variations. We haveapplied the non-rigid registration algorithm to a number of simulated MR brain images of a digital phantom whichhave been degraded by a simulated intensity shading and a known deformation. In addition, we have applied thealgorithm for the non-rigid registration of eight pre- and post-operative brain MR images which were acquired withan interventional MR scanner and therefore have substantial intensity shading due to RF field inhomogeneities. Inall cases the second-order estimate of mutual information leads to robust and accurate registration.

  14. Modelling nutritional mutualisms: challenges and opportunities for data integration.

    PubMed

    Clark, Teresa J; Friel, Colleen A; Grman, Emily; Shachar-Hill, Yair; Friesen, Maren L

    2017-09-01

    Nutritional mutualisms are ancient, widespread, and profoundly influential in biological communities and ecosystems. Although much is known about these interactions, comprehensive answers to fundamental questions, such as how resource availability and structured interactions influence mutualism persistence, are still lacking. Mathematical modelling of nutritional mutualisms has great potential to facilitate the search for comprehensive answers to these and other fundamental questions by connecting the physiological and genomic underpinnings of mutualisms with ecological and evolutionary processes. In particular, when integrated with empirical data, models enable understanding of underlying mechanisms and generalisation of principles beyond the particulars of a given system. Here, we demonstrate how mathematical models can be integrated with data to address questions of mutualism persistence at four biological scales: cell, individual, population, and community. We highlight select studies where data has been or could be integrated with models to either inform model structure or test model predictions. We also point out opportunities to increase model rigour through tighter integration with data, and describe areas in which data is urgently needed. We focus on plant-microbe systems, for which a wealth of empirical data is available, but the principles and approaches can be generally applied to any nutritional mutualism. © 2017 John Wiley & Sons Ltd/CNRS.

  15. A novel obligate cultivation mutualism between damselfish and Polysiphonia algae.

    PubMed

    Hata, Hiroki; Kato, Makoto

    2006-12-22

    In cultivation mutualisms, farming animals prepare fields for cultivars, enhance their growth and harvest them. For example, in terrestrial ecosystems, plant-herbivore cultivation mutualisms arose between humans and their crops only relatively recently. We discovered an obligate cultivation mutualism between a damselfish and an alga in a coral reef ecosystem. The damselfish, Stegastes nigricans, manages algal farms through territorial defence against the invading grazers and through weeding of unpalatable algae. As a result, the algal farms of S. nigricans are dominated by one species, Polysiphonia sp. We performed an exhaustive survey of algal assemblages inside and outside the territories of five damselfish species around the Ryukyu Islands, Japan, using molecular and morphological characteristics. Polysiphonia sp. 1 grew exclusively inside the farms of S. nigricans, and never elsewhere. Since only Polysiphonia sp. 1 is harvested and consumed by the damselfish as a staple food, this interdependent relationship is an obligate cultivation mutualism. This is the first record of an obligate plant-herbivore cultivation mutualism in a marine ecosystem. Our data also suggest that three other Polysiphonia species are facultatively mutual with, commensal with, or parasitic on other damselfish species.

  16. A novel obligate cultivation mutualism between damselfish and Polysiphonia algae

    PubMed Central

    Hata, Hiroki; Kato, Makoto

    2006-01-01

    In cultivation mutualisms, farming animals prepare fields for cultivars, enhance their growth and harvest them. For example, in terrestrial ecosystems, plant–herbivore cultivation mutualisms arose between humans and their crops only relatively recently. We discovered an obligate cultivation mutualism between a damselfish and an alga in a coral reef ecosystem. The damselfish, Stegastes nigricans, manages algal farms through territorial defence against the invading grazers and through weeding of unpalatable algae. As a result, the algal farms of S. nigricans are dominated by one species, Polysiphonia sp. We performed an exhaustive survey of algal assemblages inside and outside the territories of five damselfish species around the Ryukyu Islands, Japan, using molecular and morphological characteristics. Polysiphonia sp. 1 grew exclusively inside the farms of S. nigricans, and never elsewhere. Since only Polysiphonia sp. 1 is harvested and consumed by the damselfish as a staple food, this interdependent relationship is an obligate cultivation mutualism. This is the first record of an obligate plant–herbivore cultivation mutualism in a marine ecosystem. Our data also suggest that three other Polysiphonia species are facultatively mutual with, commensal with, or parasitic on other damselfish species. PMID:17148297

  17. Mutuality and the social regulation of neural threat responding.

    PubMed

    Coan, James A; Kasle, Shelley; Jackson, Alice; Schaefer, Hillary S; Davidson, Richard J

    2013-01-01

    Recent studies have shown that the presence of a caring relational partner can attenuate neural responses to threat. Here we report reanalyzed data from Coan, Schaefer, and Davidson ( 2006 ), investigating the role of relational mutuality in the neural response to threat. Mutuality reflects the degree to which couple members show mutual interest in the sharing of internal feelings, thoughts, aspirations, and joys - a vital form of responsiveness in attachment relationships. We predicted that wives who were high (versus low) in perceived mutuality, and who attended the study session with their husbands, would show reduced neural threat reactivity in response to mild electric shocks. We also explored whether this effect would depend on physical contact (hand-holding). As predicted, we observed that higher mutuality scores corresponded with decreased neural threat responding in the right dorsolateral prefrontal cortex and supplementary motor cortex. These effects were independent of hand-holding condition. These findings suggest that higher perceived mutuality corresponds with decreased self-regulatory effort and attenuated preparatory motor activity in response to threat cues, even in the absence of direct physical contact with social resources.

  18. An invasive plant-fungal mutualism reduces arthropod diversity.

    PubMed

    Rudgers, Jennifer A; Clay, Keith

    2008-08-01

    Ecological theory holds that competition and predation are the most important biotic forces affecting the composition of communities. Here, we expand this framework by demonstrating that mutualism can fundamentally alter community and food web structure. In large, replicated field plots, we manipulated the mutualism between a dominant plant (Lolium arundinaceum) and symbiotic fungal endophyte (Neotyphodium coenophialum). The presence of the mutualism reduced arthropod abundance up to 70%, reduced arthropod diversity nearly 20%, shifted arthropod species composition relative to endophyte-free plots and suppressed the biomass and richness of other plant species in the community. Herbivorous arthropods were more strongly affected than carnivores, and for both herbivores and carnivores, effects of the mutualism appeared to propagate indirectly via organisms occurring more basally in the food web. The influence of the mutualism was as great or greater than previously documented effects of competition and predation on arthropod communities. Our work demonstrates that a keystone mutualism can significantly reduce arthropod biodiversity at a broad community scale.

  19. Spectral image analysis of mutual illumination between florescent objects.

    PubMed

    Tominaga, Shoji; Kato, Keiji; Hirai, Keita; Horiuchi, Takahiko

    2016-08-01

    This paper proposes a method for modeling and component estimation of the spectral images of the mutual illumination phenomenon between two fluorescent objects. First, we briefly describe the bispectral characteristics of a single fluorescent object, which are summarized as a Donaldson matrix. We suppose that two fluorescent objects with different bispectral characteristics are located close together under a uniform illumination. Second, we model the mutual illumination between two objects. It is shown that the spectral composition of the mutual illumination is summarized with four components: (1) diffuse reflection, (2) diffuse-diffuse interreflection, (3) fluorescent self-luminescence, and (4) interreflection by mutual fluorescent illumination. Third, we develop algorithms for estimating the spectral image components from the observed images influenced by the mutual illumination. When the exact Donaldson matrices caused by the mutual illumination influence are unknown, we have to solve a non-linear estimation problem to estimate both the spectral functions and the location weights. An iterative algorithm is then proposed to solve the problem based on the alternate estimation of the spectral functions and the location weights. In our experiments, the feasibility of the proposed method is shown in three cases: the known Donaldson matrices, weak interreflection, and strong interreflection.

  20. Effects of a water-soluble forskolin derivative (NKH477) and a membrane-permeable cyclic AMP analogue on noradrenaline-induced Ca2+ mobilization in smooth muscle of rabbit mesenteric artery.

    PubMed Central

    Ito, S.; Suzuki, S.; Itoh, T.

    1993-01-01

    1. Effects were studied of 6-(3-dimethylaminopropionyl) forskolin (NKH477), a water-soluble forskolin derivative and of dibutyryl-cyclic AMP, a membrane-permeable cyclic AMP analogue on noradrenaline (NA)-induced Ca2+ mobilization in smooth muscle strips of the rabbit mesenteric artery. The intracellular concentration of Ca2+ ([Ca2+]i), isometric force and cellular concentration of inositol 1,4,5-trisphosphate (InsP3) were measured. 2. NA (10 microM) produced a phasic, followed by a tonic increase in both [Ca2+]i and force in a solution containing 2.6 mM Ca2+. NKH477 (0.01-0.3 microM) attenuated the phasic and the tonic increases in both [Ca2+]i and force induced by 10 microM NA, in a concentration-dependent manner. 3. In Ca(2+)-free solution containing 2 mM EGTA with 5.9 mM K+, NA (10 microM) produced only phasic increases in [Ca2+]i and force. NKH477 (0.01 microM) and dibutyryl-cyclic AMP (0.1 mM) each greatly inhibited these increases. 4. NA (10 microM) led to the production of InsP3 in intact smooth muscle strips and InsP3 (10 microM) increased Ca2+ in Ca(2+)-free solution after a brief application of Ca2+ in beta-escin-skinned smooth muscle strips. NKH477 (0.01 microM) or dibutyryl-cyclic AMP (0.1 mM) modified neither the NA-induced synthesis of InsP3 in intact muscle strips nor the InsP3-induced Ca2+ release in skinned strips. 5. In Ca(2+)-free solution, high K+ (40 and 128 mM) itself failed to increase [Ca2+]i but concentration-dependently enhanced the amplitude of the increase in [Ca2+]i induced by 10 microM NA with a parallel enhancement of the maximum rate of rise.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8298800

  1. Scientists' Social Mobility and Problems of Its Regulation by the State

    ERIC Educational Resources Information Center

    Erokhina, K. S.

    2009-01-01

    The present era is characterized by scientists' high level of mobility, which is due to the characteristics of science work and its dynamic nature. Scientific activity knows no boundaries, and mobility is a vital factor of the mutual cultural and professional enrichment of scientific communities. The international migration of scientists is…

  2. Scientists' Social Mobility and Problems of Its Regulation by the State

    ERIC Educational Resources Information Center

    Erokhina, K. S.

    2009-01-01

    The present era is characterized by scientists' high level of mobility, which is due to the characteristics of science work and its dynamic nature. Scientific activity knows no boundaries, and mobility is a vital factor of the mutual cultural and professional enrichment of scientific communities. The international migration of scientists is…

  3. Continuum electromechanical modeling of protein-membrane interactions.

    PubMed

    Zhou, Y C; Lu, Benzhuo; Gorfe, Alemayehu A

    2010-10-01

    A continuum electromechanical model is proposed to describe the membrane curvature induced by electrostatic interactions in a solvated protein-membrane system. The model couples the macroscopic strain energy of membrane and the electrostatic solvation energy of the system, and equilibrium membrane deformation is obtained by minimizing the electroelastic energy functional with respect to the dielectric interface. The model is illustrated with the systems with increasing geometry complexity and captures the sensitivity of membrane curvature to the permanent and mobile charge distributions.

  4. Physics of biological membranes

    NASA Astrophysics Data System (ADS)

    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.

  5. Mutualism breakdown by amplification of Wolbachia genes.

    PubMed

    Chrostek, Ewa; Teixeira, Luis

    2015-02-01

    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  6. Mutualism Breakdown by Amplification of Wolbachia Genes

    PubMed Central

    Chrostek, Ewa; Teixeira, Luis

    2015-01-01

    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  7. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-11-01

    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 the current research, the electrical conductivity and Seebeck coefficient were measured as a function of temperature in air. Based on these measurements, the charge carrier concentration, net acceptor dopant concentration, activation energy of conduction and mobility were estimated. The studies on the fracture toughness of the LSFT and dual phase membranes at room temperature have been completed and reported previously. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affects the mechanical properties. To study the effect of temperature on the membranes when exposed to an inert environment, the membranes (LAFT and Dual phase) were heat treated at 1000 C in air and N{sub 2} atmosphere and hardness and fracture toughness of the membranes were studied after the treatment. The indentation method was used to find the fracture toughness and the effect of the heat treatment on the mechanical properties of the membranes. Further results on the investigation of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appears to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model will serve to study ''frozen'' profiles in patterned or composite membranes.

  8. Mutually exclusive redox forms of HMGB1 promote cell recruitment or proinflammatory cytokine release

    PubMed Central

    Venereau, Emilie; Casalgrandi, Maura; Schiraldi, Milena; Antoine, Daniel J.; Cattaneo, Angela; De Marchis, Francesco; Liu, Jaron; Antonelli, Antonella; Preti, Alessandro; Raeli, Lorenzo; Shams, Sara Samadi; Yang, Huan; Varani, Luca; Andersson, Ulf; Tracey, Kevin J.; Bachi, Angela; Uguccioni, Mariagrazia

    2012-01-01

    Tissue damage causes inflammation, by recruiting leukocytes and activating them to release proinflammatory mediators. We show that high-mobility group box 1 protein (HMGB1) orchestrates both processes by switching among mutually exclusive redox states. Reduced cysteines make HMGB1 a chemoattractant, whereas a disulfide bond makes it a proinflammatory cytokine and further cysteine oxidation to sulfonates by reactive oxygen species abrogates both activities. We show that leukocyte recruitment and activation can be separated. A nonoxidizable HMGB1 mutant in which serines replace all cysteines (3S-HMGB1) does not promote cytokine production, but is more effective than wild-type HMGB1 in recruiting leukocytes in vivo. BoxA, a HMGB1 inhibitor, interferes with leukocyte recruitment but not with activation. We detected the different redox forms of HMGB1 ex vivo within injured muscle. HMGB1 is completely reduced at first and disulfide-bonded later. Thus, HMGB1 orchestrates both key events in sterile inflammation, leukocyte recruitment and their induction to secrete inflammatory cytokines, by adopting mutually exclusive redox states. PMID:22869893

  9. Mobile healthcare.

    PubMed

    Morgan, Stephen A; Agee, Nancy Howell

    2012-01-01

    Mobile technology's presence in healthcare has exploded over the past five years. The increased use of mobile devices by all segments of the US population has driven healthcare systems, providers, and payers to accept this new form of communication and to develop strategies to implement and leverage the use of mobile healthcare (mHealth) within their organizations and practices. As healthcare systems move toward a more value-driven model of care, patient centeredness and engagement are the keys to success. Mobile healthcare will provide the medium to allow patients to participate more in their care. Financially, mHealth brings to providers the ability to improve efficiency and deliver savings to both them and the healthcare consumer. However, mHealth is not without challenges. Healthcare IT departments have been reluctant to embrace this shift in technology without fully addressing security and privacy concerns. Providers have been hesitant to adopt mHealth as a form of communication with patients because it breaks with traditional models. Our healthcare system has just started the journey toward the development of mHealth. We offer an overview of the mobile healthcare environment and our approach to solving the challenges it brings to healthcare organizations.

  10. Phase Equilibria and Mutual Diffusion in Polymer - Polymer Systems with Chlorine-containing Components

    NASA Astrophysics Data System (ADS)

    Chalykh, Anatolii E.; Sapozhnikova, I. N.

    1984-11-01

    The experimental studies of the phase equilibria and mutual diffusion in polymer mixtures are examined. A thermodynamic analysis of the phase equilibria in the poly(vinyl chloride) - poly(methyl methacrylate) and chloropolyethylene - poly(methyl methacrylate) systems is presented within the framework of classical and new theories; the influence of the previous history of the specimens and of the chemical structure and stereoregularity of the polymer chains on the phase composition of the mixtures is demonstrated. The translational mobility of the macromolecules in the highly elastic and highly fluid states and its role in the formation of the phase structure of the mixtures and also the irreversible changes in the phase structure on thermal decomposition of chlorine-containing polymers are considered. The bibliography includes 95 references.

  11. On the mutual information in conformal field theory

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Chen, Lin; Hao, Peng-xiang; Long, Jiang

    2017-06-01

    In this work, we study the universal behaviors in the mutual information of two disjoint spheres in a conformal field theory (CFT). By using the operator product expansion of the spherical twist operator in terms of the conformal family, we show that the large distance expansion of the mutual information can be cast in terms of the conformal blocks. We develop the 1 /n prescription to compute the coefficients before the conformal blocks. For a single conformal family, the leading nonvanishing contribution to the mutual information comes from the bilinear operators. We show that the coefficients of these operators take universal forms and such universal behavior persists in the bilinear operators with derivatives as well. Consequently the first few leading order contributions to the mutual information in CFT take universal forms. To illustrate our framework, we discuss the free scalars and free fermions in various dimensions. For the free scalars, we compute the mutual information to the next-to-leading order and find good agreement with the improved numerical lattice result. For the free fermion, we compute the leading order result, which is of universal form, and find the good match with the numerical study. Our formalism could be applied to any CFT potentially.

  12. Mutualism Disruption Threatens Global Plant Biodiversity: A Systematic Review

    PubMed Central

    Aslan, Clare E.; Zavaleta, Erika S.; Tershy, Bernie; Croll, Donald

    2013-01-01

    Background As global environmental change accelerates, biodiversity losses can disrupt interspecific interactions. Extinctions of mutualist partners can create “widow” species, which may face reduced ecological fitness. Hypothetically, such mutualism disruptions could have cascading effects on biodiversity by causing additional species coextinctions. However, the scope of this problem – the magnitude of biodiversity that may lose mutualist partners and the consequences of these losses – remains unknown. Methodology/Principal Findings We conducted a systematic review and synthesis of data from a broad range of sources to estimate the threat posed by vertebrate extinctions to the global biodiversity of vertebrate-dispersed and -pollinated plants. Though enormous research gaps persist, our analysis identified Africa, Asia, the Caribbean, and global oceanic islands as geographic regions at particular risk of disruption of these mutualisms; within these regions, percentages of plant species likely affected range from 2.1–4.5%. Widowed plants are likely to experience reproductive declines of 40–58%, potentially threatening their persistence in the context of other global change stresses. Conclusions Our systematic approach demonstrates that thousands of species may be impacted by disruption in one class of mutualisms, but extinctions will likely disrupt other mutualisms, as well. Although uncertainty is high, there is evidence that mutualism disruption directly threatens significant biodiversity in some geographic regions. Conservation measures with explicit focus on mutualistic functions could be necessary to bolster populations of widowed species and maintain ecosystem functions. PMID:23840571

  13. Persistence of pollination mutualisms in the presence of ants.

    PubMed

    Wang, Yuanshi; Wang, Shikun

    2015-01-01

    This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.

  14. Phytophagous insect-microbe mutualisms and adaptive evolutionary diversification.

    PubMed

    Janson, Eric M; Stireman, John O; Singer, Michael S; Abbot, Patrick

    2008-05-01

    Adaptive diversification is a process intrinsically tied to species interactions. Yet, the influence of most types of interspecific interactions on adaptive evolutionary diversification remains poorly understood. In particular, the role of mutualistic interactions in shaping adaptive radiations has been largely unexplored, despite the ubiquity of mutualisms and increasing evidence of their ecological and evolutionary importance. Our aim here is to encourage empirical inquiry into the relationship between mutualism and evolutionary diversification, using herbivorous insects and their microbial mutualists as exemplars. Phytophagous insects have long been used to test theories of evolutionary diversification; moreover, the diversification of a number of phytophagous insect lineages has been linked to mutualisms with microbes. In this perspective, we examine microbial mutualist mediation of ecological opportunity and ecologically based divergent natural selection for their insect hosts. We also explore the conditions and mechanisms by which microbial mutualists may either facilitate or impede adaptive evolutionary diversification. These include effects on the availability of novel host plants or adaptive zones, modifying host-associated fitness trade-offs during host shifts, creating or reducing enemy-free space, and, overall, shaping the evolution of ecological (host plant) specialization. Although the conceptual framework presented here is built on phytophagous insect-microbe mutualisms, many of the processes and predictions are broadly applicable to other mutualisms in which host ecology is altered by mutualistic interactions.

  15. A general framework for effectiveness concepts in mutualisms.

    PubMed

    Schupp, Eugene W; Jordano, Pedro; Gómez, José María

    2017-03-28

    A core interest in studies of mutualistic interactions is the 'effectiveness' of mutualists in providing benefits to their partners. In plant-animal mutualisms it is widely accepted that the total effect of a mutualist on its partner is estimated as (1) a 'quantity' component multiplied by (2) a 'quality' component, although the meanings of 'effectiveness,' 'quantity,' and 'quality' and which terms are applied to these metrics vary greatly across studies. In addition, a similar quantity × quality = total effect approach has not been applied to other types of mutualisms, although it could be informative. Lastly, when a total effect approach has been applied, it has invariably been from a phytocentric perspective, focussing on the effects of animal mutualists on their plant partner. This lack of a common framework of 'effectiveness' of mutualistic interactions limits generalisation and the development of a broader understanding of the ecology and evolution of mutualisms. In this paper, we propose a general framework and demonstrate its utility by applying it to both partners in five different types of mutualisms: pollination, seed dispersal, plant protection, rhizobial, and mycorrhizal mutualisms. We then briefly discuss the flexibility of the framework, potential limitations, and relationship to other approaches.

  16. Population dynamics and mutualism: Functional responses of benefits and costs

    USGS Publications Warehouse

    Holland, J. Nathaniel; DeAngelis, Donald L.; Bronstein, Judith L.

    2002-01-01

    We develop an approach for studying population dynamics resulting from mutualism by employing functional responses based on density‐dependent benefits and costs. These functional responses express how the population growth rate of a mutualist is modified by the density of its partner. We present several possible dependencies of gross benefits and costs, and hence net effects, to a mutualist as functions of the density of its partner. Net effects to mutualists are likely a monotonically saturating or unimodal function of the density of their partner. We show that fundamental differences in the growth, limitation, and dynamics of a population can occur when net effects to that population change linearly, unimodally, or in a saturating fashion. We use the mutualism between senita cactus and its pollinating seed‐eating moth as an example to show the influence of different benefit and cost functional responses on population dynamics and stability of mutualisms. We investigated two mechanisms that may alter this mutualism's functional responses: distribution of eggs among flowers and fruit abortion. Differences in how benefits and costs vary with density can alter the stability of this mutualism. In particular, fruit abortion may allow for a stable equilibrium where none could otherwise exist.

  17. 12 CFR Appendix A to Part 239 - Mutual Holding Company Model Charter

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Mutual Holding Company Model Charter A Appendix... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Pt. 239, App. A Appendix A to Part 239—Mutual Holding Company Model Charter FEDERAL MUTUAL HOLDING COMPANY CHARTER Section 1: Corporate...

  18. 12 CFR Appendix C to Part 239 - Mutual Holding Company Model Bylaws

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Mutual Holding Company Model Bylaws C Appendix... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Pt. 239, App. C Appendix C to Part 239—Mutual Holding Company Model Bylaws MODEL BYLAWS FOR MUTUAL HOLDING COMPANIES The term “trustees” may...

  19. 12 CFR Appendix A to Part 239 - Mutual Holding Company Model Charter

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Mutual Holding Company Model Charter A Appendix... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Pt. 239, App. A Appendix A to Part 239—Mutual Holding Company Model Charter FEDERAL MUTUAL HOLDING COMPANY CHARTER Section 1: Corporate...

  20. 12 CFR Appendix C to Part 239 - Mutual Holding Company Model Bylaws

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Mutual Holding Company Model Bylaws C Appendix... RESERVE SYSTEM (CONTINUED) MUTUAL HOLDING COMPANIES (REGULATION MM) Pt. 239, App. C Appendix C to Part 239—Mutual Holding Company Model Bylaws MODEL BYLAWS FOR MUTUAL HOLDING COMPANIES The term “trustees” may...

  1. 77 FR 69455 - Proposed Recommendations Regarding Money Market Mutual Fund Reform

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ... OVERSIGHT COUNCIL Proposed Recommendations Regarding Money Market Mutual Fund Reform AGENCY: Financial... reforms for money market mutual funds (MMFs). Proposed Recommendations Regarding Money Market Mutual Fund... Market Mutual Fund Reform according to the instructions below. All submissions must refer to docket...

  2. 12 CFR Appendix C to Part 239 - Mutual Holding Company Model Bylaws

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Mutual Holding Company Model Bylaws C Appendix...—Mutual Holding Company Model Bylaws MODEL BYLAWS FOR MUTUAL HOLDING COMPANIES The term “trustees” may be... voted by the mutual holding company if no other instructions are received. Joint accounts shall...

  3. Diffusion of molecules and macromolecules in thylakoid membranes.

    PubMed

    Kirchhoff, Helmut

    2014-04-01

    The survival and fitness of photosynthetic organisms is critically dependent on the flexible response of the photosynthetic machinery, harbored in thylakoid membranes, to environmental changes. A central element of this flexibility is the lateral diffusion of membrane components along the membrane plane. As demonstrated, almost all functions of photosynthetic energy conversion are dependent on lateral diffusion. The mobility of both small molecules (plastoquinone, xanthophylls) as well as large protein supercomplexes is very sensitive to changes in structural boundary conditions. Knowledge about the design principles that govern the mobility of photosynthetic membrane components is essential to understand the dynamic response of the photosynthetic machinery. This review summarizes our knowledge about the factors that control diffusion in thylakoid membranes and bridges structural membrane alterations to changes in mobility and function. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Multicomponent membranes

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

  5. Mutual exclusivity in autism spectrum disorders: testing the pragmatic hypothesis.

    PubMed

    de Marchena, Ashley; Eigsti, Inge-Marie; Worek, Amanda; Ono, Kim Emiko; Snedeker, Jesse

    2011-04-01

    While there is ample evidence that children treat words as mutually exclusive, the cognitive basis of this bias is widely debated. We focus on the distinction between pragmatic and lexical constraints accounts. High-functioning children with autism spectrum disorders (ASD) offer a unique perspective on this debate, as they acquire substantial vocabularies despite impoverished social-pragmatic skills. We tested children and adolescents with ASD in a paradigm examining mutual exclusivity for words and facts. Words were interpreted contrastively more often than facts. Word performance was associated with vocabulary size; fact performance was associated with social-communication skills. Thus mutual exclusivity does not appear to be driven by pragmatics, suggesting that it is either a lexical constraint or a reflection of domain-general learning processes. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Occurrence and characteristics of mutual interference between LIDAR scanners

    NASA Astrophysics Data System (ADS)

    Kim, Gunzung; Eom, Jeongsook; Park, Seonghyeon; Park, Yongwan

    2015-05-01

    The LIDAR scanner is at the heart of object detection of the self-driving car. Mutual interference between LIDAR scanners has not been regarded as a problem because the percentage of vehicles equipped with LIDAR scanners was very rare. With the growing number of autonomous vehicle equipped with LIDAR scanner operated close to each other at the same time, the LIDAR scanner may receive laser pulses from other LIDAR scanners. In this paper, three types of experiments and their results are shown, according to the arrangement of two LIDAR scanners. We will show the probability that any LIDAR scanner will interfere mutually by considering spatial and temporal overlaps. It will present some typical mutual interference scenario and report an analysis of the interference mechanism.

  7. Arrays of mutually coupled receiver coils: theory and application.

    PubMed

    Wright, S M; Magin, R L; Kelton, J R

    1991-01-01

    Specialized receiver coils having a small sensitive region can provide an improvement in SNR for MR imaging and spectroscopy, at the expense of limiting the usable field of view. This work presents a technique for designing coil arrays that allows the size and location of the sensitive region to be selected remotely. Only one element of the coil array is directly connected to the receiver, allowing flexibility in system design and implementation. A method is presented for the analysis and design of mutually coupled coil arrays of any number of elements of arbitrary shape. The analysis includes mutual coupling effects between primary coils, to allow multiple primary coils to be used simultaneously. A controller system allows remote selection of the sensitive region and automatically matches the impedance of the array to the preamplifier. Results obtained using a mutually coupled coil array designed for spine imaging are shown.

  8. Mutual information after a local quench in conformal field theory

    NASA Astrophysics Data System (ADS)

    Asplund, Curtis T.; Bernamonti, Alice

    2014-03-01

    We compute the entanglement entropy and mutual information for two disjoint intervals in two-dimensional conformal field theories as a function of time after a local quench, using the replica trick and boundary conformal field theory. We obtain explicit formulas for the universal contributions, which are leading in the regimes of, for example, close or well-separated intervals of fixed length. The results are largely consistent with the quasiparticle picture, in which entanglement above that present in the ground state is carried by pairs of entangled freely propagating excitations. We also calculate the mutual information for two disjoint intervals in a proposed holographic local quench, whose holographic energy-momentum tensor matches the conformal field theory one. We find that the holographic mutual information shows qualitative differences from the conformal field theory results and we discuss possible interpretations of this.

  9. Sparse Bayesian Learning for DOA Estimation with Mutual Coupling

    PubMed Central

    Dai, Jisheng; Hu, Nan; Xu, Weichao; Chang, Chunqi

    2015-01-01

    Sparse Bayesian learning (SBL) has given renewed interest to the problem of direction-of-arrival (DOA) estimation. It is generally assumed that the measurement matrix in SBL is precisely known. Unfortunately, this assumption may be invalid in practice due to the imperfect manifold caused by unknown or misspecified mutual coupling. This paper describes a modified SBL method for joint estimation of DOAs and mutual coupling coefficients with uniform linear arrays (ULAs). Unlike the existing method that only uses stationary priors, our new approach utilizes a hierarchical form of the Student t prior to enforce the sparsity of the unknown signal more heavily. We also provide a distinct Bayesian inference for the expectation-maximization (EM) algorithm, which can update the mutual coupling coefficients more efficiently. Another difference is that our method uses an additional singular value decomposition (SVD) to reduce the computational complexity of the signal reconstruction process and the sensitivity to the measurement noise. PMID:26501284

  10. Homosexual mutuality: variation on a theme by Erik Erikson.

    PubMed

    Sohier, R

    The exploratory descriptive study described here was conducted in order to produce the initial empirical evidence to support reformulation of the theoretical construct of heterosexual mutuality (Erikson, 1975). Six persons were interviewed in depth on tape in order to locate them on one of four identity statuses constructed by Marcia (1964, 1966, 1973). The tool was modified and extended to meet the purposes of the study. The questions are directed toward illumination of conflictual moments in the life cycle when the ability to make appropriate decisions engenders character growth, and supports the personality integration of adulthood. An ability to make decisions results in personality integration. The small study provides evidence that there exists a homosexual mutuality (contrary to Erikson's position) which is no less valuable than heterosexual mutuality, and forms an equal basis for adult personality integration.

  11. Empirical study of the tails of mutual fund size

    NASA Astrophysics Data System (ADS)

    Schwarzkopf, Yonathan; Farmer, J. Doyne

    2010-06-01

    The mutual fund industry manages about a quarter of the assets in the U.S. stock market and thus plays an important role in the U.S. economy. The question of how much control is concentrated in the hands of the largest players is best quantitatively discussed in terms of the tail behavior of the mutual fund size distribution. We study the distribution empirically and show that the tail is much better described by a log-normal than a power law, indicating less concentration than, for example, personal income. The results are highly statistically significant and are consistent across fifteen years. This contradicts a recent theory concerning the origin of the power law tails of the trading volume distribution. Based on the analysis in a companion paper, the log-normality is to be expected, and indicates that the distribution of mutual funds remains perpetually out of equilibrium.

  12. Rényi generalizations of the conditional quantum mutual information

    SciTech Connect

    Berta, Mario; Seshadreesan, Kaushik P.; Wilde, Mark M.

    2015-02-15

    The conditional quantum mutual information I(A; B|C) of a tripartite state ρ{sub ABC} is an information quantity which lies at the center of many problems in quantum information theory. Three of its main properties are that it is non-negative for any tripartite state, that it decreases under local operations applied to systems A and B, and that it obeys the duality relation I(A; B|C) = I(A; B|D) for a four-party pure state on systems ABCD. The conditional mutual information also underlies the squashed entanglement, an entanglement measure that satisfies all of the axioms desired for an entanglement measure. As such, it has been an open question to find Rényi generalizations of the conditional mutual information, that would allow for a deeper understanding of the original quantity and find applications beyond the traditional memoryless setting of quantum information theory. The present paper addresses this question, by defining different α-Rényi generalizations I{sub α}(A; B|C) of the conditional mutual information, some of which we can prove converge to the conditional mutual information in the limit α → 1. Furthermore, we prove that many of these generalizations satisfy non-negativity, duality, and monotonicity with respect to local operations on one of the systems A or B (with it being left as an open question to prove that monotonicity holds with respect to local operations on both systems). The quantities defined here should find applications in quantum information theory and perhaps even in other areas of physics, but we leave this for future work. We also state a conjecture regarding the monotonicity of the Rényi conditional mutual informations defined here with respect to the Rényi parameter α. We prove that this conjecture is true in some special cases and when α is in a neighborhood of one.

  13. Augmenting Surface Interaction through Context-Sensitive Mobile Devices

    NASA Astrophysics Data System (ADS)

    Olwal, Alex

    We discuss the benefits of using a mobile device to expand and improve the interactions on a large touch-sensitive surface. The mobile device’s denser arrangement of pixels and touch-sensor elements, and its rich set of mechanical on-board input controls, can be leveraged for increased expressiveness, visual feedback and more precise direct-manipulation. We also show how these devices can support unique input from multiple simultaneous users in collaborative scenarios. Handheld mobile devices and large interactive surfaces can be mutually beneficial in numerous ways, while their complementary nature allows them to preserve the behavior of the original user interface.

  14. Biochemical Machines for the Interconversion of Mutual Information and Work

    NASA Astrophysics Data System (ADS)

    McGrath, Thomas; Jones, Nick S.; ten Wolde, Pieter Rein; Ouldridge, Thomas E.

    2017-01-01

    We propose a physically realizable information-driven device consisting of an enzyme in a chemical bath, interacting with pairs of molecules prepared in correlated states. These correlations persist without direct interaction and thus store free energy equal to the mutual information. The enzyme can harness this free energy, and that stored in the individual molecular states, to do chemical work. Alternatively, the enzyme can use the chemical driving to create mutual information. A modified system can function without external intervention, approaching biological systems more closely.

  15. Analysis and Synthesis of Microstrip Antennas Including Mutual Coupling

    DTIC Science & Technology

    1988-09-01

    E N 11. TITLE (/b*I* Secwfty OuodlCaUOn~) Analysis and Synthesis of Microstrip Antennas Including Mutual Coupling 12. PERSONAL AUTHOR(S) K~oichiro...GROUP SUB-GROUP Array Antennas, Microstrip Antennas, Array Analysis, Array Synthesis, Array Theory, Microwave Network Analysi! 19. ABSTRACT (Continue...VIRGI-J~NIA TECH ANALYSIS AND SYNTHESIS OF [. MICROSTRIP ANTENNAS INCLUDING MUTUAL COUPLING o0000 0 0 a o 0 0 0 0 0 o 0 00 0 00 o00000 0o000 0 0 0 a 0 0 0o

  16. Cross Correlation versus Normalized Mutual Information on Image Registration

    NASA Technical Reports Server (NTRS)

    Tan, Bin; Tilton, James C.; Lin, Guoqing

    2016-01-01

    This is the first study to quantitatively assess and compare cross correlation and normalized mutual information methods used to register images in subpixel scale. The study shows that the normalized mutual information method is less sensitive to unaligned edges due to the spectral response differences than is cross correlation. This characteristic makes the normalized image resolution a better candidate for band to band registration. Improved band-to-band registration in the data from satellite-borne instruments will result in improved retrievals of key science measurements such as cloud properties, vegetation, snow and fire.

  17. Synchronization in a Mutualism Ecosystem Induced by Noise Correlation

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Rong; Shao, Yuan-Zhi; Bie, Meng-Jie; He, Zhen-Hui

    2008-09-01

    Understanding the cause of the synchronization of population evolution is an important issue for ecological improvement. Here we present a Lotka Volterra-type model driven by two correlated environmental noises and show, via theoretical analysis and direct simulation, that noise correlation can induce a synchronization of the mutualists. The time series of mutual species exhibit a chaotic-like fluctuation, which is independent of the noise correlation, however, the chaotic fluctuation of mutual species ratio decreases with the noise correlation. A quantitative parameter defined for characterizing chaotic fluctuation provides a good approach to measure when the complete synchronization happens.

  18. Separability criteria via sets of mutually unbiased measurements.

    PubMed

    Liu, Lu; Gao, Ting; Yan, Fengli

    2015-08-17

    Mutually unbiased measurements (MUMs) are generalized from the concept of mutually unbiased bases (MUBs) and include the complete set of MUBs as a special case, but they are superior to MUBs as they do not need to be rank one projectors. We investigate entanglement detection using sets of MUMs and derive separability criteria for multipartite qudit systems, arbitrary high-dimensional bipartite systems of a d1-dimensional subsystem and a d2-dimensional subsystem, and multipartite systems of multi-level subsystems. These criteria are of the advantages of more effective and wider application range than previous criteria. They provide experimental implementation in detecting entanglement of unknown quantum states.

  19. Mutual Impact of Diabetes Mellitus and Tuberculosis in China.

    PubMed

    Cheng, Jun; Zhang, Hui; Zhao, Yan Lin; Wang, Li Xia; Chen, Ming Ting

    2017-05-01

    China has a double burden of diabetes mellitus and tuberculosis, and many studies have been carried out on the mutual impact of these two diseases. This paper systematically reviewed studies conducted in China covering the mutual impact of epidemics of diabetes and tuberculosis, the impact of diabetes on multi-drug resistant tuberculosis and on the tuberculosis clinical manifestation and treatment outcome, the yields of bi-directional screening, and economic evaluation for tuberculosis screening among diabetes patients. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  20. Analysis of the Mutual Inductance Particle Velocimeter (MIPV)

    DTIC Science & Technology

    1974-11-01

    yKeU’v-T-.-’j-i^fi.T mmmmmm AD/A-004 219 ANALYSIS OF THE MUTUAL INDUCTANCE PARTICLE VELOCIMETER (MIPV) Joseph D. Renick Air Force...REPORT DOCUMENTATION PAGE 1. REPORT NUMBER AFWL-TR-74-205 2. GOVT ACCESSION NO 4. TITLE fand SubtUU.) ANALYSIS OF THE MUTUAL INDUCTANCE...Resistance as a Function of Stress for Several Metals 109 C-2 Geometry for One-Dimensional Shock Response Analysis HI C-3 Shock Equilibration of

  1. Lipid membranes on nanostructured silicon.

    SciTech Connect

    Slade, Andrea Lynn; Lopez, Gabriel P.; Ista, Linnea K.; O'Brien, Michael J.; Sasaki, Darryl Yoshio; Bisong, Paul; Zeineldin, Reema R.; Last, Julie A.; Brueck, Stephen R. J.

    2004-12-01

    A unique composite nanoscale architecture that combines the self-organization and molecular dynamics of lipid membranes with a corrugated nanotextured silicon wafer was prepared and characterized with fluorescence microscopy and scanning probe microscopy. The goal of this project was to understand how such structures can be assembled for supported membrane research and how the interfacial interactions between the solid substrate and the soft, self-assembled material create unique physical and mechanical behavior through the confinement of phases in the membrane. The nanometer scale structure of the silicon wafer was produced through interference lithography followed by anisotropic wet etching. For the present study, a line pattern with 100 nm line widths, 200 nm depth and a pitch of 360 nm pitch was fabricated. Lipid membranes were successfully adsorbed on the structured silicon surface via membrane fusion techniques. The surface topology of the bilayer-Si structure was imaged using in situ tapping mode atomic force microscopy (AFM). The membrane was observed to drape over the silicon structure producing an undulated topology with amplitude of 40 nm that matched the 360 nm pitch of the silicon structure. Fluorescence recovery after photobleaching (FRAP) experiments found that on the microscale those same structures exhibit anisotropic lipid mobility that was coincident with the silicon substructure. The results showed that while the lipid membrane maintains much of its self-assembled structure in the composite architecture, the silicon substructure indeed influences the dynamics of the molecular motion within the membrane.

  2. [Epiretinal membranes].

    PubMed

    Dupas, B; Tadayoni, R; Gaudric, A

    2015-11-01

    Idiopathic epiretinal membranes represent a common condition, and are present in approximately 10% of people over the age of 70 years. They are idiopathic in 80% of cases, or may be secondary to various conditions such as a prior retinal detachment, or vascular or inflammatory retinal diseases. The main symptoms are visual loss and metamorphopsia. The diagnosis of epiretinal membrane is currently facilitated by OCT, which provides prognostic and therapeutic decision-making assistance. Surgery for epiretinal membranes is currently well codified through sutureless vitrectomy and dyes. Dissection of the membrane (with or without associated peeling of the internal limiting membrane) ensures good anatomical and functional results, while being relatively minimally invasive. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. Membrane structure and radiation and hyperthermic damage

    NASA Astrophysics Data System (ADS)

    Yatvin, Milton B.; Grummer, Mary A.

    The general structure of the biological membrane and its involvement in cell damage from radiation and hyperthermic insults are discussed using bacterial cells as an example. Bacterial cells are useful models for these types of studies because they possess a simple membrane system whose composition can be readily altered. Also, various strains exist having different sensitivities to radiation and heat. For example, the response of Escherichia coli cells to ionizing radiation is found to be related to the degree of association between its DNA and membrane. Likewise, membrane lipids reportedly are important components in the cellular response to radiation. For example, radiation-induced lipid peroxidation leads to both structural and functional alterations in the membranes which must be considered to fully comprehend the biological effects of radiation. The physical state of the membrane during radiation exposure also is involved in the cellular response to radiation. Functional changes during radiation have been ascribed to changes in the protein component of the membrane. Other alterations which may play a role in radiation-induced cell damage include electrophoretic mobility of cells, membrane transport mechanisms, and membrane polysaccharide content. The cell membrane, particularly the lipid component, is an important target in hyperthermic cell killing. The composition and organization of the membrane lipids can influence a cell's response to heat. Heat-induced changes in membrane lipids lead to altered distribution of E. coli proteins, particularly their translocation to the outer membrane. These and other aspects are discussed in this review.

  4. Flexible Use of Mutual Exclusivity in Word Learning

    ERIC Educational Resources Information Center

    Kalashnikova, Marina; Mattock, Karen; Monaghan, Padraic

    2016-01-01

    From an early age, children apply the mutual exclusivity (ME) assumption, demonstrating preference for one-to-one mappings between words and their referents. However, for the acquisition of referentially overlapping terms, ME use must be suspended. We test whether contextual cues to intended meaning, in the form of presence of a speaker, may be…

  5. A Mutual Support Group for Young Problem Gamblers

    ERIC Educational Resources Information Center

    Binde, Per

    2012-01-01

    A Swedish mutual support group for young problem gamblers is described and discussed. During the study period, 116 weekly meetings occurred, usually involving six to ten participants; in total, 69 problem gamblers (66 male and three female), aged 17-25, and 23 partners and friends attended the meetings. Half the gamblers had problems with Internet…

  6. A Mutual Support Group for Young Problem Gamblers

    ERIC Educational Resources Information Center

    Binde, Per

    2012-01-01

    A Swedish mutual support group for young problem gamblers is described and discussed. During the study period, 116 weekly meetings occurred, usually involving six to ten participants; in total, 69 problem gamblers (66 male and three female), aged 17-25, and 23 partners and friends attended the meetings. Half the gamblers had problems with Internet…

  7. Flexible Use of Mutual Exclusivity in Word Learning

    ERIC Educational Resources Information Center

    Kalashnikova, Marina; Mattock, Karen; Monaghan, Padraic

    2016-01-01

    From an early age, children apply the mutual exclusivity (ME) assumption, demonstrating preference for one-to-one mappings between words and their referents. However, for the acquisition of referentially overlapping terms, ME use must be suspended. We test whether contextual cues to intended meaning, in the form of presence of a speaker, may be…

  8. No effect of diffraction on Pluto-Charon mutual events

    NASA Technical Reports Server (NTRS)

    Tholen, D. J.; Hubbard, W. B.

    1988-01-01

    Mulholland and Gustafson (1987) made the interesting suggestion that observations of Pluto-Charon mutual events might show significant dependence on both wavelength and telescope aperture because of diffraction effects. In this letter, observations are presented that show the predicted effects to be absent and demonstrate that the parameters of the system are such that the events can be accurately analyzed with geometrical optics.

  9. Mutual Exclusivity in Autism Spectrum Disorders: Testing the Pragmatic Hypothesis

    ERIC Educational Resources Information Center

    de Marchena, Ashley; Eigsti, Inge-Marie; Worek, Amanda; Ono, Kim Emiko; Snedeker, Jesse

    2011-01-01

    While there is ample evidence that children treat words as mutually exclusive, the cognitive basis of this bias is widely debated. We focus on the distinction between pragmatic and lexical constraints accounts. High-functioning children with autism spectrum disorders (ASD) offer a unique perspective on this debate, as they acquire substantial…

  10. Synchronization and symmetry breaking in mutually coupled fiber lasers.

    PubMed

    Rogers-Dakin, Elizabeth A; García-Ojalvo, Jordi; DeShazer, David J; Roy, Rajarshi

    2006-04-01

    We experimentally study the synchronization and the emergence of leader-follower dynamics in two time-delayed mutually coupled fiber ring lasers. We utilize spatiotemporal representations of time series to establish the roles of leader and follower in the synchronized dynamics.

  11. Synchronization and symmetry breaking in mutually coupled fiber lasers

    NASA Astrophysics Data System (ADS)

    Rogers-Dakin, Elizabeth A.; García-Ojalvo, Jordi; Deshazer, David J.; Roy, Rajarshi

    2006-04-01

    We experimentally study the synchronization and the emergence of leader-follower dynamics in two time-delayed mutually coupled fiber ring lasers. We utilize spatiotemporal representations of time series to establish the roles of leader and follower in the synchronized dynamics.

  12. Ecological genomics of mutualism decline in nitrogen-fixing bacteria

    PubMed Central

    Klinger, Christie R.; Lau, Jennifer A.

    2016-01-01

    Anthropogenic changes can influence mutualism evolution; however, the genomic regions underpinning mutualism that are most affected by environmental change are generally unknown, even in well-studied model mutualisms like the interaction between legumes and their nitrogen (N)-fixing rhizobia. Such genomic information can shed light on the agents and targets of selection maintaining cooperation in nature. We recently demonstrated that N-fertilization has caused an evolutionary decline in mutualistic partner quality in the rhizobia that form symbiosis with clover. Here, population genomic analyses of N-fertilized versus control rhizobium populations indicate that evolutionary differentiation at a key symbiosis gene region on the symbiotic plasmid (pSym) contributes to partner quality decline. Moreover, patterns of genetic variation at selected loci were consistent with recent positive selection within N-fertilized environments, suggesting that N-rich environments might select for less beneficial rhizobia. By studying the molecular population genomics of a natural bacterial population within a long-term ecological field experiment, we find that: (i) the N environment is indeed a potent selective force mediating mutualism evolution in this symbiosis, (ii) natural variation in rhizobium partner quality is mediated in part by key symbiosis genes on the symbiotic plasmid, and (iii) differentiation at selected genes occurred in the context of otherwise recombining genomes, resembling eukaryotic models of adaptation. PMID:26962142

  13. Mutual information in a dilute, asymmetric neural network model

    NASA Astrophysics Data System (ADS)

    Greenfield, Elliot

    We study the computational properties of a neural network consisting of binary neurons with dilute asymmetric synaptic connections. This simple model allows us to simulate large networks which can reflect more of the architecture and dynamics of real neural networks. Our main goal is to determine the dynamical behavior that maximizes the network's ability to perform computations. To this end, we apply information theory, measuring the average mutual information between pairs of pre- and post-synaptic neurons. Communication of information between neurons is an essential requirement for collective computation. Previous workers have demonstrated that neural networks with asymmetric connections undergo a transition from ordered to chaotic behavior as certain network parameters, such as the connectivity, are changed. We find that the average mutual information has a peak near the order-chaos transition, implying that the network can most efficiently communicate information between cells in this region. The mutual information peak becomes increasingly pronounced when the basic model is extended to incorporate more biologically realistic features, such as a variable threshold and nonlinear summation of inputs. We find that the peak in mutual information near the phase transition is a robust feature of the system for a wide range of assumptions about post-synaptic integration.

  14. Institutionalized Mutuality in Canada-China Management Education Collaboration

    ERIC Educational Resources Information Center

    Wei, Shuguang; Liu, Xianjun

    2015-01-01

    This paper examines the Canada-China Management Education Program (CCMEP, 1983-1996) between the University of Toronto (UT) and Huazhong University of Science and Technology (HUST). In this paper, we create a "Three Levels/Four Parameters" analytical framework, based on the concept of mutuality from Johan Galtung (1980) and the concept…

  15. Mutual information area laws for thermal free fermions

    NASA Astrophysics Data System (ADS)

    Bernigau, H.; Kastoryano, M. J.; Eisert, J.

    2015-02-01

    We provide a rigorous and asymptotically exact expression of the mutual information of translationally invariant free fermionic lattice systems in a Gibbs state. In order to arrive at this result, we introduce a novel framework for computing determinants of Töplitz operators with smooth symbols, and for treating Töplitz matrices with system size dependent entries. The asymptotically exact mutual information for a partition of the 1D lattice satisfies an area law, with a prefactor which we compute explicitly. As examples, we discuss the fermionic XX model in one dimension and free fermionic models on the torus in higher dimensions in detail. Special emphasis is put on the discussion of the temperature dependence of the mutual information, scaling like the logarithm of the inverse temperature, hence confirming an expression suggested by conformal field theory. We also comment on the applicability of the formalism to treat open systems driven by quantum noise. In the appendix, we derive useful bounds to the mutual information in terms of purities. Finally, we provide a detailed error analysis for finite system sizes. This analysis is valuable in its own right for the abstract theory of Töplitz determinants.

  16. Language Experience Shapes the Development of the Mutual Exclusivity Bias

    ERIC Educational Resources Information Center

    Houston-Price, Carmel; Caloghiris, Zoe; Raviglione, Eleonora

    2010-01-01

    Halberda (2003) demonstrated that 17-month-old infants, but not 14- or 16-month-olds, use a strategy known as mutual exclusivity (ME) to identify the meanings of new words. When 17-month-olds were presented with a novel word in an intermodal preferential looking task, they preferentially fixated a novel object over an object for which they already…

  17. Chinese and American Women: Issues of Mutual Concern. Wingspread Brief.

    ERIC Educational Resources Information Center

    Johnson Foundation, Inc., Racine, WI.

    This article briefly describes a conference of Chinese and American women held to discuss womens' issues and promote mutual understanding between the two groups. The cultural exchange of information at the conference focused on discussion of the All China Womens' Federation (ACWF); the roles of women in China and the United States in the areas of…

  18. Ecological genomics of mutualism decline in nitrogen-fixing bacteria.

    PubMed

    Klinger, Christie R; Lau, Jennifer A; Heath, Katy D

    2016-03-16

    Anthropogenic changes can influence mutualism evolution; however, the genomic regions underpinning mutualism that are most affected by environmental change are generally unknown, even in well-studied model mutualisms like the interaction between legumes and their nitrogen (N)-fixing rhizobia. Such genomic information can shed light on the agents and targets of selection maintaining cooperation in nature. We recently demonstrated that N-fertilization has caused an evolutionary decline in mutualistic partner quality in the rhizobia that form symbiosis with clover. Here, population genomic analyses of N-fertilized versus control rhizobium populations indicate that evolutionary differentiation at a key symbiosis gene region on the symbiotic plasmid (pSym) contributes to partner quality decline. Moreover, patterns of genetic variation at selected loci were consistent with recent positive selection within N-fertilized environments, suggesting that N-rich environments might select for less beneficial rhizobia. By studying the molecular population genomics of a natural bacterial population within a long-term ecological field experiment, we find that: (i) the N environment is indeed a potent selective force mediating mutualism evolution in this symbiosis, (ii) natural variation in rhizobium partner quality is mediated in part by key symbiosis genes on the symbiotic plasmid, and (iii) differentiation at selected genes occurred in the context of otherwise recombining genomes, resembling eukaryotic models of adaptation. © 2016 The Author(s).

  19. Mutual Antipathies and Their Significance in Middle Childhood and Adolescence.

    ERIC Educational Resources Information Center

    Abecassis, Maurissa; Hartup, Willard W.; Haselager, Gerbert J. T.; Scholte, Ron H. J.; Van Lieshout, Cornelis F. M.

    2002-01-01

    Investigated children's and adolescents' involvement in mutual antipathies. Found that children and boys of all ages were more frequently involved in same-sex antipathies; involvement in mixed-sex antipathies was comparable for both genders. Same-sex antipathies were associated with antisocial behavior and social withdrawal for both age and gender…

  20. Antagonists in Mutual Antipathies: A Person-Oriented Approach

    ERIC Educational Resources Information Center

    Guroglu, Berna; Haselager, Gerbert J. T.; van Lieshout, Cornelis F. M.; Scholte, Ron H. J.

    2009-01-01

    This study investigated the heterogeneity of mutual antipathy relationships. Separate cluster analyses of peer interactions of early adolescents (mean age 11 years) and adolescents (mean age of 14) yielded 3 "types of individuals" in each age group, namely Prosocial, Antisocial, and Withdrawn. Prevalence analysis of the 6 possible combinations of…

  1. Using Mutual Information for Adaptive Item Comparison and Student Assessment

    ERIC Educational Resources Information Center

    Liu, Chao-Lin

    2005-01-01

    The author analyzes properties of mutual information between dichotomous concepts and test items. The properties generalize some common intuitions about item comparison, and provide principled foundations for designing item-selection heuristics for student assessment in computer-assisted educational systems. The proposed item-selection strategies…

  2. Antagonists in Mutual Antipathies: A Person-Oriented Approach

    ERIC Educational Resources Information Center

    Guroglu, Berna; Haselager, Gerbert J. T.; van Lieshout, Cornelis F. M.; Scholte, Ron H. J.

    2009-01-01

    This study investigated the heterogeneity of mutual antipathy relationships. Separate cluster analyses of peer interactions of early adolescents (mean age 11 years) and adolescents (mean age of 14) yielded 3 "types of individuals" in each age group, namely Prosocial, Antisocial, and Withdrawn. Prevalence analysis of the 6 possible combinations of…

  3. Mutual Suppression: Comment on Paulhus et Al. (2004)

    ERIC Educational Resources Information Center

    Nickerson, Carol

    2008-01-01

    Paulhus, Robins, Trzesniewski, and Tracy ("Multivariate Behavioral Research," 2004, 39, 305-328) suggested that the three types of two-predictor suppression situations--classical suppression, cooperative suppression, and net suppression--can all be considered special cases of mutual suppression, in that the magnitude of each of the two…

  4. Evolution of the Fusarium–Euwallacea ambrosia beetle mutualism

    USDA-ARS?s Scientific Manuscript database

    The Euwallacea – Fusarium mutualistic symbiosis represents one of the independent evolutionary origins of fungus-farming. Diversification time estimates place the evolutionary origin of this mutualism in the early Miocene approximately 21 million years ago. Fusarium is best known as one of the most ...

  5. A color-mediated mutualism between two arthropod predators.

    PubMed

    Peng, Po; Blamires, Sean J; Agnarsson, Ingi; Lin, Hui-Chen; Tso, I-Min

    2013-01-21

    The nature of interactions between animals varies depending on local selection pressure, trophic status of the participants, and evolutionary circumstances. Body coloration and other visual signals may also affect animal interactions. Game theory posits that if one species provides a "service" in exchange for a "goods," a mutualism may ensue. Mutualisms between two predators are rare because of multiple conflicts of interests (but see [11, 12]). We used a nocturnal system traditionally considered kleptoparasitic to determine whether a mutualism ensues because the body coloration of the kleptoparasite is beneficial to the host. Specifically, we tested whether the silver body of the spider Argyrodes fissifrons (Theridiidae) attracts prey for the larger, duller spider Cyrtophora unicolor (Araneidae), which reciprocates by allowing A. fissifrons access to its web. When A. fissifrons were removed from C. unicolor webs, the webs intercepted fewer prey. Furthermore, covering the silver body parts of A. fissifrons also resulted in a reduction in prey interception by C. unicolor webs. We thus show that a mutualism between two arthropod predators can be mediated by the coloration of one species enhancing the foraging gains of another.

  6. Efficient Estimation of Mutual Information for Strongly Dependent Variables

    DTIC Science & Technology

    2015-05-11

    between Total Cell Phones (Y ), Num- ber of Female Cervical Cancer cases (Z), and rate of Tuberculosis deaths (X). Since the variable Z (the number...indi- cates that a higher number of cell phones per person are predictive of lower tuberculosis death rate. One 283 Ecient Estimation of Mutual

  7. Mutual Intercultural Relations among University Students in Canada

    ERIC Educational Resources Information Center

    Gui, Yongxia; Safdar, Saba; Berry, John

    2016-01-01

    The current study examies the views of both international and domestic students in Canada using the conceptual and empirical framework from the MIRIPS (Mutual Intercultural Relations in Plural Societies) project (http://www.victoria.ac.nz/cacr/research/mirips). Two hypotheses were examined. First is the "multiculturalism hypothesis"…

  8. The blind leading the blind: Mutual refinement of approximate theories

    NASA Technical Reports Server (NTRS)

    Kedar, Smadar T.; Bresina, John L.; Dent, C. Lisa

    1991-01-01

    The mutual refinement theory, a method for refining world models in a reactive system, is described. The method detects failures, explains their causes, and repairs the approximate models which cause the failures. The approach focuses on using one approximate model to refine another.

  9. A Swedish Mutual Support Society of Problem Gamblers

    ERIC Educational Resources Information Center

    Binde, Per

    2012-01-01

    Mutual support societies for problem gamblers have existed in Sweden for 20 years. They have helped more people with gambling problems than any other institution inside or outside the Swedish health care system. This paper outlines the background of these societies and describes the meetings of one of them. Data come from interviews with members…

  10. A Swedish Mutual Support Society of Problem Gamblers

    ERIC Educational Resources Information Center

    Binde, Per

    2012-01-01

    Mutual support societies for problem gamblers have existed in Sweden for 20 years. They have helped more people with gambling problems than any other institution inside or outside the Swedish health care system. This paper outlines the background of these societies and describes the meetings of one of them. Data come from interviews with members…

  11. Mutual Support Groups for Long-Term Recipients of TANF

    ERIC Educational Resources Information Center

    Anderson-Butcher, Dawn; Khairallah, Angela Oliver; Race-Bigelow, Janis

    2004-01-01

    This study examined the effect of involvement in mutual support groups on long-term recipients of Temporary Assistance for Needy Families (TANF) and other vulnerable individuals. From qualitative interviews with nine group members, the study identified key themes, benefits, and barriers related to involvement in the groups. Content analysis of the…

  12. Enhancing Web-Based Courses through a Mutual Aid Framework

    ERIC Educational Resources Information Center

    Wilke, Dina J.; Randolph, Karen A.; Vinton, Linda

    2009-01-01

    Students taking a class together belong to a group where members typically develop a sense of connection to each other by engaging in mutual support and assistance through shared experiences and knowledge. Some have argued that the lack of face-to-face interaction precludes such processes and prevents the effective teaching of social work in an…

  13. 47 CFR 25.155 - Mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 25.155 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Processing of Applications § 25.155 Mutually exclusive... NGSO-like space station license, within the meaning of § 25.157, will be entitled to comparative...

  14. 47 CFR 22.131 - Procedures for mutually exclusive applications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) (according to the filing dates) as acceptable for filing. (4) Window filing group. A window filing group comprises mutually exclusive applications whose filing date is within an announced filing window. An announced filing window is a period of time between and including two specific dates, which are the first...

  15. Mutual Aid: A Key to Survival for Black Americans

    ERIC Educational Resources Information Center

    Norman, Alex J.

    1977-01-01

    In the Brotherhood Crusade, a black mutual aid, self-help organization, Los Angeles blacks joined together to effect independence within the professions and the social service delivery systems, rejecting incorporation into the United Way, the major L.A. fund-raising organization. This article presents findings of a study of Crusade participants.…

  16. 12 CFR 563.74 - Mutual capital certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... dividend may be paid if such payment would constitute a violation of 12 U.S.C. 1828(b); (v) Not be... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Mutual capital certificates. 563.74 Section 563... of filing of the application are in accordance with the provisions of this section. (b)...

  17. 12 CFR 563.74 - Mutual capital certificates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... dividend may be paid if such payment would constitute a violation of 12 U.S.C. 1828(b); (v) Not be... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Mutual capital certificates. 563.74 Section 563... of filing of the application are in accordance with the provisions of this section. (b)...

  18. Multi-Transiting Systems and Exoplanet Mutual Events

    NASA Astrophysics Data System (ADS)

    Coughlin, Jared; Ragozzine, D.; Holman, M. J.

    2011-01-01

    Until recently, studies of transiting exoplanets- planets that cross in front of their host star- have focused almost exclusively upon systems where there is only one transiting planet. Those studies that have considered additional planets have mostly done so with the goal of determining the perturbing effects that additional planets would have upon the orbit, and therefore the light curve, of the transiting planet. This work considers, in detail, a specific type of event known as an exoplanet mutual event. Such events occur when one planet passes in front of another. While such events can occur whether or not these planets are transiting, predicting and understanding these events is best done in systems with multiple transiting planets. We estimate, through an ensemble simulation, how frequently exoplanet mutual events occur and which systems are most likely to undergo exoplanet mutual events. We also investigate what information can be learned about not only the planets themselves but also the orbital architecture in such systems. We conclude that while ODT (overlapping double-transit) events occur with a much lower frequency than PPO (planet-planet occultation) events, ODT mutual events are capable of producing detectable signals, that Kepler will detect a few, and recommend that candidate systems for these events, such as KOI 191, be observed in short cadence(Steffen et. al 2010, Holman et. al 2010). This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 0754568 and by the Smithsonian Institution.

  19. 12 CFR 544.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... by the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  20. 12 CFR 144.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the institution... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  1. 12 CFR 144.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the institution... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  2. 12 CFR 544.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... by the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  3. 12 CFR 144.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the institution... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  4. 12 CFR 544.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... by the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  5. 12 CFR 544.5 - Federal mutual savings association bylaws.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... by the association. (3) Corporate governance procedures. A Federal mutual association may elect to follow the corporate governance procedures of the laws of the state where the main office of the... corporate governance procedures, and shall file a copy of such bylaws, which are effective upon...

  6. Is Action Research Necessarily Collaborative? Changing Mutuality within a Project

    ERIC Educational Resources Information Center

    Sousa, Francisco

    2016-01-01

    This article reports a study on collaboration within an action research project that was conducted by university researchers and elementary school teachers in the Azores, Portugal. More specifically, it examines how different kinds of participants worked together in different phases of the project. The notion of mutuality (i.e., the relative…

  7. Mutual Information Item Selection in Adaptive Classification Testing

    ERIC Educational Resources Information Center

    Weissman, Alexander

    2007-01-01

    A general approach for item selection in adaptive multiple-category classification tests is provided. The approach uses mutual information (MI), a special case of the Kullback-Leibler distance, or relative entropy. MI works efficiently with the sequential probability ratio test and alleviates the difficulties encountered with using other local-…

  8. Functional analysis of mutual behavior in laboratory rats (Rattus norvegicus)

    PubMed Central

    Tan, Lavinia; Hackenberg, Timothy D.

    2015-01-01

    Three pairs of rats were trained to synchronize their lever pressing according to a mutual reinforcement contingency, in which alternating lever presses that fell within a 500-ms window were reinforced with food. In Experiment 1, rats worked in adjacent chambers separated by a transparent barrier, and the effects of the mutual reinforcement contingency were compared to those under yoked-control conditions that provided the same rate of food reinforcement but without the temporal coordination response requirement. In Experiment 2, coordinated behavior was compared with and without a barrier, and across different barrier types: transparent, opaque, wire mesh. In Experiment 3, the effects of social familiarity were assessed by switching partners, enabling a comparison of coordinated behavior with familiar and unfamiliar partners. The overall pattern of results shows that the coordinated behavior of two rats was (a) maintained by mutual reinforcement contingencies, (b) unrelated to the type or presence of a barrier separating the rats, and (c) sufficiently flexible to adjust to the presence and behavior of an unfamiliar partner. Taken as a whole, the study illustrates a promising approach to conceptualizing and analyzing behavioral mechanisms of mutual behavior, an important component of an integrated study of social behavior. PMID:26479279

  9. 47 CFR 101.45 - Mutually exclusive applications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Applications and Licenses Processing of Applications § 101.45 Mutually... fixed point-to-point microwave applications for authorization under this part will be entitled to... not available in other bands. During the initial filing window, frequency coordination is not...

  10. 47 CFR 101.45 - Mutually exclusive applications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Applications and Licenses Processing of Applications § 101.45 Mutually... fixed point-to-point microwave applications for authorization under this part will be entitled to... not available in other bands. During the initial filing window, frequency coordination is not...

  11. 47 CFR 101.45 - Mutually exclusive applications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Applications and Licenses Processing of Applications § 101.45 Mutually... fixed point-to-point microwave applications for authorization under this part will be entitled to... not available in other bands. During the initial filing window, frequency coordination is not...

  12. Friendships: From Cultural Guidelines to Mutually Agreed Upon Norms.

    ERIC Educational Resources Information Center

    Walker, Alexis J.

    Theorists have predicted that individuals in a relationship initially follow social norms and later follow the mutually-agreed-upon norms which have evolved from the relationship. Since social norms prescribe sex-stereotyped behavior, an androgynous person may initially behave in a sex-typed way. Same-sex pairs (N=26) of undergraduates, matched on…

  13. Is Action Research Necessarily Collaborative? Changing Mutuality within a Project

    ERIC Educational Resources Information Center

    Sousa, Francisco

    2016-01-01

    This article reports a study on collaboration within an action research project that was conducted by university researchers and elementary school teachers in the Azores, Portugal. More specifically, it examines how different kinds of participants worked together in different phases of the project. The notion of mutuality (i.e., the relative…

  14. Mutual Funds as a Form of Collective Investment in Russia

    ERIC Educational Resources Information Center

    Tershukova, Marina B.; Savinov, Oleg G.; Zhegalova, Elena V.; Zhuruhinc, Georgy I.; Zhegalova, Alexandra S.

    2016-01-01

    The relevance of the research problem inspired with the fact nowadays there is a need for theoretical generalization based on international experience the essence of the collective investment system and the rationale for prioritizing the mutual funds development as the most attractive form of collective investment. The goal of the article lies in…

  15. Mutual Intercultural Relations among University Students in Canada

    ERIC Educational Resources Information Center

    Gui, Yongxia; Safdar, Saba; Berry, John

    2016-01-01

    The current study examies the views of both international and domestic students in Canada using the conceptual and empirical framework from the MIRIPS (Mutual Intercultural Relations in Plural Societies) project (http://www.victoria.ac.nz/cacr/research/mirips). Two hypotheses were examined. First is the "multiculturalism hypothesis"…

  16. The Environment of Classification: The Concept of Mutual Exclusivity

    ERIC Educational Resources Information Center

    Jones, Kevin P.

    1973-01-01

    Classification is interpreted so as to incorporate all attempts at the imposition of order upon our observations of the universe. In this article, the fundamental bases of classification are examined: in particular the alien notions of mutual exclusivity and the use of inflexible structures to mirror a dynamic universe. (26 references) (Author/KE)

  17. 12 CFR 163.74 - Mutual capital certificates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... applicant's charter, constitution or bylaws. (c) Application form; supporting information. An application..., constitution or bylaws or other actions conferring such authority shall have been approved pursuant to the procedures and requirements set forth in the mutual association's charter, constitution or bylaws, or as may...

  18. The Social Capital of Self-Help Mutual Aid Groups.

    ERIC Educational Resources Information Center

    Banks, Erik

    1997-01-01

    Argues that small-group mutual aid organizations are successful voluntary associations that attract members even in our individualistic and commodity-driven culture because they provide valuable collective benefits that can only be enjoyed in common. Small groups as a source of social capital have implications for the study of helping…

  19. Measurement reduction for mutual coupling calibration in DOA estimation

    NASA Astrophysics Data System (ADS)

    Aksoy, Taylan; Tuncer, T. Engin

    2012-01-01

    Mutual coupling is an important source of error in antenna arrays that should be compensated for super resolution direction-of-arrival (DOA) algorithms, such as Multiple Signal Classification (MUSIC) algorithm. A crucial step in array calibration is the determination of the mutual coupling coefficients for the antenna array. In this paper, a system theoretic approach is presented for the mutual coupling characterization of antenna arrays. The comprehension and implementation of this approach is simple leading to further advantages in calibration measurement reduction. In this context, a measurement reduction method for antenna arrays with omni-directional and identical elements is proposed which is based on the symmetry planes in the array geometry. The proposed method significantly decreases the number of measurements during the calibration process. This method is evaluated using different array types whose responses and the mutual coupling characteristics are obtained through numerical electromagnetic simulations. It is shown that a single calibration measurement is sufficient for uniform circular arrays. Certain important and interesting characteristics observed during the experiments are outlined.

  20. A Delicate Balance: Maintaining Mutualism to Prevent Disease

    PubMed Central

    Van Tyne, Daria; Gilmore, Michael S.

    2015-01-01

    The intestinal microbial ecosystem is complex, and few of the principles that contribute to homeostasis in health are well understood. Pham et al. (2014) show that a network including the epithelial interleukin-22 receptor protects against infection with the opportunistic pathogen Enterococcus faecalis through promotion of host-microbiota mutualism. PMID:25299326

  1. Cellular calcium mobilization

    SciTech Connect

    Daniel, E.E.

    1984-01-01

    In vascular and other smooth muscles, occurrence of intracellular Ca stores which can be mobilized to support contraction may be a general phenomenon. The Ca stores are characterized by the requirement for release by high concentrations of agonists acting on plasma membrane receptors, by the failure of the released Ca2+ to recycle to the store, by the occurrence of rapid refilling of the store from the extracellular space, and by disappearance of the store when the plasma membrane is made leaky by saponin. In contrast to agonist-released Ca stores, those released by caffeine to support contraction in Ca2+-free solutions are more slowly lost and refilled, are not always emptied when the agonist-related store is emptied, and do not disappear after saponin treatment. Stores released by agonists have been suggested to be in the endoplasmic reticulum near the plasma membrane or at the inner aspect of the plasma membrane related to high affinity, pH-dependent Ca-binding sites. Caffeine-released stores are assumed to be in endoplasmic reticulum. Continued exposure of some tissues to Ca2+-free solutions unmasks what is considered to be a recycling Ca store releasable by agonists. Release of Ca2+ and its reaccumulation in this store appear to be slower than at the nonrecycling store. The contractions which persist for many hours in Ca2+-free solution are inhibited temporarily by Ca2+ restoration. Existence of a recycling store of releasable Ca2+ requires occurrence of mechanisms to abolish Ca2+ extrusion or leak-out of the cell and to ensure recycling to the same store.

  2. Mutual coupling, channel model, and BER for curvilinear antenna arrays

    NASA Astrophysics Data System (ADS)

    Huang, Zhiyong

    This dissertation introduces a wireless communications system with an adaptive beam-former and investigates its performance with different antenna arrays. Mutual coupling, real antenna elements and channel models are included to examine the system performance. In a beamforming system, mutual coupling (MC) among the elements can significantly degrade the system performance. However, MC effects can be compensated if an accurate model of mutual coupling is available. A mutual coupling matrix model is utilized to compensate mutual coupling in the beamforming of a uniform circular array (UCA). Its performance is compared with other models in uplink and downlink beamforming scenarios. In addition, the predictions are compared with measurements and verified with results from full-wave simulations. In order to accurately investigate the minimum mean-square-error (MSE) of an adaptive array in MC, two different noise models, the environmental and the receiver noise, are modeled. The minimum MSEs with and without data domain MC compensation are analytically compared. The influence of mutual coupling on the convergence is also examined. In addition, the weight compensation method is proposed to attain the desired array pattern. Adaptive arrays with different geometries are implemented with the minimum MSE algorithm in the wireless communications system to combat interference at the same frequency. The bit-error-rate (BER) of systems with UCA, uniform rectangular array (URA) and UCA with center element are investigated in additive white Gaussian noise plus well-separated signals or random direction signals scenarios. The output SINR of an adaptive array with multiple interferers is analytically examined. The influence of the adaptive algorithm convergence on the BER is investigated. The UCA is then investigated in a narrowband Rician fading channel. The channel model is built and the space correlations are examined. The influence of the number of signal paths, number of the

  3. Mobile Customer Relationship Management and Mobile Security

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  4. Evolutionary origin of insect–Wolbachia nutritional mutualism

    PubMed Central

    Nikoh, Naruo; Hosokawa, Takahiro; Moriyama, Minoru; Oshima, Kenshiro; Hattori, Masahira; Fukatsu, Takema

    2014-01-01

    Obligate insect–bacterium nutritional mutualism is among the most sophisticated forms of symbiosis, wherein the host and the symbiont are integrated into a coherent biological entity and unable to survive without the partnership. Originally, however, such obligate symbiotic bacteria must have been derived from free-living bacteria. How highly specialized obligate mutualisms have arisen from less specialized associations is of interest. Here we address this evolutionary issue by focusing on an exceptional insect–Wolbachia nutritional mutualism. Although Wolbachia endosymbionts are ubiquitously found in diverse insects and generally regarded as facultative/parasitic associates for their insect hosts, a Wolbachia strain associated with the bedbug Cimex lectularius, designated as wCle, was shown to be essential for host’s growth and reproduction via provisioning of B vitamins. We determined the 1,250,060-bp genome of wCle, which was generally similar to the genomes of insect-associated facultative Wolbachia strains, except for the presence of an operon encoding the complete biotin synthetic pathway that was acquired via lateral gene transfer presumably from a coinfecting endosymbiont Cardinium or Rickettsia. Nutritional and physiological experiments, in which wCle-infected and wCle-cured bedbugs of the same genetic background were fed on B-vitamin–manipulated blood meals via an artificial feeding system, demonstrated that wCle certainly synthesizes biotin, and the wCle-provisioned biotin significantly contributes to the host fitness. These findings strongly suggest that acquisition of a single gene cluster consisting of biotin synthesis genes underlies the bedbug–Wolbachia nutritional mutualism, uncovering an evolutionary transition from facultative symbiosis to obligate mutualism facilitated by lateral gene transfer in an endosymbiont lineage. PMID:24982177

  5. Evolutionary origin of insect-Wolbachia nutritional mutualism.

    PubMed

    Nikoh, Naruo; Hosokawa, Takahiro; Moriyama, Minoru; Oshima, Kenshiro; Hattori, Masahira; Fukatsu, Takema

    2014-07-15

    Obligate insect-bacterium nutritional mutualism is among the most sophisticated forms of symbiosis, wherein the host and the symbiont are integrated into a coherent biological entity and unable to survive without the partnership. Originally, however, such obligate symbiotic bacteria must have been derived from free-living bacteria. How highly specialized obligate mutualisms have arisen from less specialized associations is of interest. Here we address this evolutionary issue by focusing on an exceptional insect-Wolbachia nutritional mutualism. Although Wolbachia endosymbionts are ubiquitously found in diverse insects and generally regarded as facultative/parasitic associates for their insect hosts, a Wolbachia strain associated with the bedbug Cimex lectularius, designated as wCle, was shown to be essential for host's growth and reproduction via provisioning of B vitamins. We determined the 1,250,060-bp genome of wCle, which was generally similar to the genomes of insect-associated facultative Wolbachia strains, except for the presence of an operon encoding the complete biotin synthetic pathway that was acquired via lateral gene transfer presumably from a coinfecting endosymbiont Cardinium or Rickettsia. Nutritional and physiological experiments, in which wCle-infected and wCle-cured bedbugs of the same genetic background were fed on B-vitamin-manipulated blood meals via an artificial feeding system, demonstrated that wCle certainly synthesizes biotin, and the wCle-provisioned biotin significantly contributes to the host fitness. These findings strongly suggest that acquisition of a single gene cluster consisting of biotin synthesis genes underlies the bedbug-Wolbachia nutritional mutualism, uncovering an evolutionary transition from facultative symbiosis to obligate mutualism facilitated by lateral gene transfer in an endosymbiont lineage.

  6. Crystalline Membranes

    NASA Technical Reports Server (NTRS)

    Tsapatsis, Michael (Inventor); Lai, Zhiping (Inventor)

    2008-01-01

    In certain aspects, the invention features methods for forming crystalline membranes (e.g., a membrane of a framework material, such as a zeolite) by inducing secondary growth in a layer of oriented seed crystals. The rate of growth of the seed crystals in the plane of the substrate is controlled to be comparable to the rate of growth out of the plane. As a result, a crystalline membrane can form a substantially continuous layer including grains of uniform crystallographic orientation that extend through the depth of the layer.

  7. Going mobile

    NASA Astrophysics Data System (ADS)

    Brus, Eric

    1987-12-01

    By 1990, all metropolitan areas in the U.S. and rural areas close to major cities or towns are expected to have cellular telephone service; 22 Canadian cities also feature cellular service. To supply mobile telecommunication services to sparsely-populated rural areas, a mobile satellite service (MSS) is now being developed. In this paper the projected possibilities of the MSS system are discussed, including a possibility that a piggyback-MSS payload be added to the GSTAR-4 satellite which is scheduled for a launch in 1988 or 1989; one in which some of the hardware from aborted direct-broadcast satellites would be used; and the possibility of building a new MSS satellite with large servicing capacity. Canada is planning to launch its own mobile satellite, MSAT, in the early 1990s. The MSS is expected to be 'generic', serving not only people on land but maritime and aeronautical users as well. It will also offer major benefits to truck and automobile drivers, making it possible for them to conduct business or to call for assistance from locations beyond the range of cellular systems.

  8. 26 CFR 1.831-1 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... insurance companies not carrying on an insurance business within the United States, and all mutual marine...) Foreign insurance companies not carrying on an insurance business within the United States are not taxable... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Tax on insurance companies (other than life...

  9. 26 CFR 1.831-1 - Tax on insurance companies (other than life or mutual), mutual marine insurance companies, and...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... foreign insurance companies not carrying on an insurance business within the United States, and all mutual... Code. (d) Foreign insurance companies not carrying on an insurance business within the United States... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Tax on insurance companies (other than life...

  10. Membranes, mechanics, and intracellular transport

    NASA Astrophysics Data System (ADS)

    Parthasarathy, Raghuveer

    2012-10-01

    Cellular membranes are remarkable materials -- self-assembled, flexible, two-dimensional fluids. Understanding how proteins manipulate membrane curvature is crucial to understanding the transport of cargo in cells, yet the mechanical activities of trafficking proteins remain poorly understood. Using an optical-trap based assay involving dynamic deformation of biomimetic membranes, we have examined the behavior of Sar1, a key component of the COPII family of transport proteins. We find that Sar1 from yeast (S. cerevisiae) lowers membrane rigidity by up to 100% as a function of its concentration, thereby lowering the energetic cost of membrane deformation. Human Sar1 proteins can also lower the mechanical rigidity of the membranes to which they bind. However, unlike the yeast proteins, the rigidity is not a monotonically decreasing function of concentration but rather shows increased rigidity and decreased mobility at high concentrations that implies interactions between proteins. In addition to describing this study of membrane mechanics, I'll also discuss some topics relevant to a range of biophysical investigations, such as the insights provided by imaging methods and open questions in the dynamics of multicellular systems.

  11. Biological membranes

    PubMed Central

    Watson, Helen

    2015-01-01

    Biological membranes allow life as we know it to exist. They form cells and enable separation between the inside and outside of an organism, controlling by means of their selective permeability which substances enter and leave. By allowing gradients of ions to be created across them, membranes also enable living organisms to generate energy. In addition, they control the flow of messages between cells by sending, receiving and processing information in the form of chemical and electrical signals. This essay summarizes the structure and function of membranes and the proteins within them, and describes their role in trafficking and transport, and their involvement in health and disease. Techniques for studying membranes are also discussed. PMID:26504250

  12. Mutual relations between sleep deprivation, sleep stealers and risk behaviours in adolescents

    PubMed Central

    Paiva, Teresa; Gaspar, Tania; Matos, Margarida Gaspar

    2016-01-01

    Objectives The aim is to evaluate the mutual influences between sleep duration/sleep deprivation (SD) and the sleep stealers/adolescent risk behaviours. Methods The national survey is a component of the Health Behaviour in School-Aged Children (HBSC) study, it is based on a school-based self-completed questionnaire; 3476 students were randomly selected from 139 randomly chosen Portuguese schools using as an unit the class, 53.8% were girls; 45.9% attended the 8th grade and 54.1% the 10th grade; the mean age was 14.9 years. The measured variables were: 1) gender and age; 2) sociodemographics; 3) sleep duration during the week and during weekends and computed SD; 4) screen time (computer use during the week and during the week end (PC use); watching TV and mobile phone use; 5) earlier sexual behaviour; 6) violent behaviours: fights, use of weapons; 7) use of tobacco, alcohol and drugs. The statistical analysis included Pearson chi-square tests and logistic regression. Results Excessive use of mobile phone, of computer use during weekdays, and internet facilities; substance use; violence and earlier sexual relations had significantly higher prevalence in sleep deprived adolescents. By logistic regression only using PC during weekdays, tobacco, drugs and weapons were associated to SD, while SD was associated to PC use during weekdays, tobacco use and drugs’ use. Computer uses tend to be associated among themselves. Mobile phone is associated with computer practices and with alcohol and tobacco use. Tobacco is associated with most risk behaviours. Alcohol use is associated with other substance use, computer use and violent behaviours. Violence behaviours, earlier sex and drugs use tend to be associated among themselves. Conclusions Sleep stealers use and risk behaviours are more prevalent in sleep deprived adolescents, but, in spite of significant individual associations, models of risk behaviours are still lacking. PMID:27226817

  13. Solid colloids with surface-mobile linkers.

    PubMed

    van der Meulen, Stef A J; Helms, Gesa; Dogterom, Marileen

    2015-06-17

    In this report we review the possibilities of using colloids with surface mobile linkers for the study of colloidal self-assembly processes. A promising route to create systems with mobile linkers is the use of lipid (bi-)layers. These lipid layers can be either used in the form of vesicles or as coatings for hard colloids and emulsion droplets. Inside the lipid bilayers molecules can be inserted via membrane anchors. Due to the fluidity of the lipid bilayer, the anchored molecules remain mobile. The use of different lipid mixtures even allows creating Janus-like particles that exhibit directional bonding if linkers are used which have a preference for a certain lipid phase. In nature mobile linkers can be found e.g. as receptors in cells. Therefore, towards the end of the review, we also briefly address the possibility of using colloids with surface mobile linkers as model systems to mimic cell-cell interactions and cell adhesion processes.

  14. Solid colloids with surface-mobile linkers

    NASA Astrophysics Data System (ADS)

    van der Meulen, Stef A. J.; Helms, Gesa; Dogterom, Marileen

    2015-06-01

    In this report we review the possibilities of using colloids with surface mobile linkers for the study of colloidal self-assembly processes. A promising route to create systems with mobile linkers is the use of lipid (bi-)layers. These lipid layers can be either used in the form of vesicles or as coatings for hard colloids and emulsion droplets. Inside the lipid bilayers molecules can be inserted via membrane anchors. Due to the fluidity of the lipid bilayer, the anchored molecules remain mobile. The use of different lipid mixtures even allows creating Janus-like particles that exhibit directional bonding if linkers are used which have a preference for a certain lipid phase. In nature mobile linkers can be found e.g. as receptors in cells. Therefore, towards the end of the review, we also briefly address the possibility of using colloids with surface mobile linkers as model systems to mimic cell-cell interactions and cell adhesion processes.

  15. Criticality in Plasma Membranes

    NASA Astrophysics Data System (ADS)

    Machta, Ben; Sethna, James; Veatch, Sarah; Papanikolaou, Stefanos

    2010-03-01

    Recent work in giant plasma membrane vesicles (GPMVs) isolated from living cells demonstrated that they can be tuned with a single parameter (temperature) to criticality, not far from in vivo temperatures [1,2]. Criticality requires the fine-tuning of two parameters suggesting important biological function, and its presence resolves many of the paradoxes associated with putative lipid rafts. Here we present a minimal model of membrane inhomogeneities. We incorporate criticality using a conserved order parameter Ising model coupled to a simple actin cytoskeleton interacting through fields which act as point-like pinning sites. Using this model we make a host of experimentally testable predictions that are in line with recent published findings. At physiological temperatures we find inhomogeneities in the form of critical fluctuations with a length scale of roughly 20nm. Individual constituents making up these liquid domains are mobile, though they diffuse anomalously, but the correlated regions themselves can last as long as the cytoskeleton persists. We explain this by considering the effective long ranged interaction mediated by the Ising order parameter. In general we find Ising criticality organizes and spatially segregates membrane components by providing a channel for interaction over large distances. [1] Veatch et al., ACS Chem Biol. 2008 3(5):287-93 [2] Honerkamp-Smith, Veatch, and Keller, Biochim Biophys Acta. 2008 (in press)

  16. Mobile Mechanism Suitable for Rough Terrain Vehicle

    NASA Astrophysics Data System (ADS)

    Hoshino, Haruo; Ishikawa, Atsuo; Fukuda, Toshino; Hasegawa, Yasuhisa

    We propose an interconnected suspension mechanism that is applicable to rough terrain mobile robots for construction sites. All wheels can follow on uneven ground by moving mutually with an interconnected suspension mechanism. And, it is possible to control the posture of the robot simply using the mechanism. In this paper, the structural and mechanical characteristics of the mechanism are discussed and the ground contact loads of wheels are analyzed. It was confirmed the mechanism has enough ability for moving on an uneven floor and posture control through experiments with an experimental rough terrain moving robot.

  17. Networks in financial markets based on the mutual information rate.

    PubMed

    Fiedor, Paweł

    2014-05-01

    In the last few years there have been many efforts in econophysics studying how network theory can facilitate understanding of complex financial markets. These efforts consist mainly of the study of correlation-based hierarchical networks. This is somewhat surprising as the underlying assumptions of research looking at financial markets are that they are complex systems and thus behave in a nonlinear manner, which is confirmed by numerous studies, making the use of correlations which are inherently dealing with linear dependencies only baffling. In this paper we introduce a way to incorporate nonlinear dynamics and dependencies into hierarchical networks to study financial markets using mutual information and its dynamical extension: the mutual information rate. We show that this approach leads to different results than the correlation-based approach used in most studies, on the basis of 91 companies listed on the New York Stock Exchange 100 between 2003 and 2013, using minimal spanning trees and planar maximally filtered graphs.

  18. The Mutual Impedance Probe (RPC-MIP) onboard ROSETTA

    NASA Astrophysics Data System (ADS)

    Henri, Pierre; Lebreton, Jean-Pierre; Béghin, Christian; Décréau, Pierrette; Grard, Réjean; Hamelin, Michel; Mazelle, Christian; Randriamboarison, Orélien; Schmidt, Walter; Winterhalter, Daniel; Aouad, Youcef; Lagoutte, Dominique; Vallières, Xavier

    2014-05-01

    The ROSETTA mission will reach the comet 67P/Churyumov-Gerasimenko in August 2014 and enable, for the first time, the in situ survey of a comet activity during along orbit. On board the ROSETTA orbiter, the Mutual Impedance Probe (MIP) is one of the instruments of the Rosetta Plasma Consortium (RPC) that aims at monitoring the cometary plasma environment. MIP is a quadrupolar probe that measures the frequency response of the coupling impedance between two emitting and two receiving dipoles. The electron density and temperature are derived from the resonance peak and the interference pattern of the mutual impedance spectrum. We will describe this instrument and discuss the preliminary results obtained during the third ROSETTA Earth flyby to show its expected capabilities. The RPC switch ON for the post-hibernation recommissioning is planned at the end of March. The health status of the instrument will be discussed.

  19. Mutualism supports biodiversity when the direct competition is weak

    PubMed Central

    Pascual-García, Alberto; Bastolla, Ugo

    2017-01-01

    A key question of theoretical ecology is which properties of ecosystems favour their stability and help maintaining biodiversity. This question recently reconsidered mutualistic systems, generating intense controversy about the role of mutualistic interactions and their network architecture. Here we show analytically and verify with simulations that reducing the effective interspecific competition and the propagation of perturbations positively influences structural stability against environmental perturbations, enhancing persistence. Noteworthy, mutualism reduces the effective interspecific competition only when the direct interspecific competition is weaker than a critical value. This critical competition is in almost all cases larger in pollinator networks than in random networks with the same connectance. Highly connected mutualistic networks reduce the propagation of environmental perturbations, a mechanism reminiscent of MacArthur’s proposal that ecosystem complexity enhances stability. Our analytic framework rationalizes previous contradictory results, and it gives valuable insight on the complex relationship between mutualism and biodiversity. PMID:28232740

  20. Kepler-108: A Mutually Inclined Giant Planet System

    NASA Astrophysics Data System (ADS)

    Mills, Sean M.; Fabrycky, Daniel C.

    2017-01-01

    The vast majority of well studied giant-planet systems, including the solar system, are nearly coplanar, which implies dissipation within a primordial gas disk. However, intrinsic instability may lead to planet-planet scattering, which often produces non-coplanar, eccentric orbits. Planet scattering theories have been developed to explain observed high-eccentricity systems and also hot Jupiters; thus far their predictions for mutual inclination (I) have barely been tested. Here we characterize a highly mutually inclined (I={24}-8+11°), moderately eccentric (e≳ 0.1) giant planet system: Kepler-108. This system consists of two approximately Saturn-mass planets with periods of approximately 49 and 190 days around a star with a wide (˜300 au) binary companion in an orbital configuration inconsistent with a purely disk migration origin.

  1. Kepler-108: A Mutually Inclined Giant Planet System

    NASA Astrophysics Data System (ADS)

    Mills, Sean M.; Fabrycky, Daniel

    2016-06-01

    The vast majority of well studied giant-planet systems, including the Solar System, are nearly coplanar which implies dissipation within a primordial gas disk. However, intrinsic instability may lead to planet-planet scattering, which often produces non-coplanar, eccentric orbits. Planet scattering theories have been developed to explain observed high eccentricity systems and possibly hot Jupiters; thus far their predictions for mutual inclination (I) have barely been tested. Here we characterize a highly mutually-inclined (I ~ 15-60 degrees), moderately eccentric (e > 0.1) giant planet system: Kepler-108. This system consists of two Saturn mass planets with periods of ~49 and ~190 days around a star with a wide (~300 AU) binary companion in an orbital configuration inconsistent with a purely disk migration origin.

  2. Networks in financial markets based on the mutual information rate

    NASA Astrophysics Data System (ADS)

    Fiedor, Paweł

    2014-05-01

    In the last few years there have been many efforts in econophysics studying how network theory can facilitate understanding of complex financial markets. These efforts consist mainly of the study of correlation-based hierarchical networks. This is somewhat surprising as the underlying assumptions of research looking at financial markets are that they are complex systems and thus behave in a nonlinear manner, which is confirmed by numerous studies, making the use of correlations which are inherently dealing with linear dependencies only baffling. In this paper we introduce a way to incorporate nonlinear dynamics and dependencies into hierarchical networks to study financial markets using mutual information and its dynamical extension: the mutual information rate. We show that this approach leads to different results than the correlation-based approach used in most studies, on the basis of 91 companies listed on the New York Stock Exchange 100 between 2003 and 2013, using minimal spanning trees and planar maximally filtered graphs.

  3. Refining and Mutual Separation of Rare Earths Using Biomass Wastes

    NASA Astrophysics Data System (ADS)

    Inoue, Katsutoshi; Alam, Shafiq

    2013-10-01

    Two different types of adsorption gels were prepared from biomass wastes. The first gel was produced from astringent persimmon peel rich in persimmon tannin, a polyphenol compound, which was prepared by means of simple dehydration condensation reaction using concentrated sulfuric acid for crosslinking. This adsorption gel was intended to be employed for the removal of radioactive elements, uranium (U(VI)) and thorium (Th(IV)), from rare earths. The second gel was prepared from chitosan, a basic polysaccharide, produced from shells of crustaceans such as crabs, shrimps, prawns, and other biomass wastes generated in marine product industry, by immobilizing functional groups of complexanes such as ethylendiaminetetraacetic acid and diethylentriaminepentaacetic acid (DTPA). This gel was developed for the mutual separation of rare earths. Of the two adsorption gels evaluated, the DTPA immobilized chitosan exhibited the most effective mutual separation among light rare earths.

  4. Improving quantum state estimation with mutually unbiased bases.

    PubMed

    Adamson, R B A; Steinberg, A M

    2010-07-16

    When used in quantum state estimation, projections onto mutually unbiased bases have the ability to maximize information extraction per measurement and to minimize redundancy. We present the first experimental demonstration of quantum state tomography of two-qubit polarization states to take advantage of mutually unbiased bases. We demonstrate improved state estimation as compared to standard measurement strategies and discuss how this can be understood from the structure of the measurements we use. We experimentally compared our method to the standard state estimation method for three different states and observe that the infidelity was up to 1.84 ± 0.06 times lower by using our technique than it was by using standard state estimation methods.

  5. Onset of fights and mutual assessment in ant founding queens.

    PubMed

    Berthelot, Kévin; Portugal, Felipe Ramon; Jeanson, Raphaël

    2017-03-01

    In animals, the progress and outcome of contests can be influenced by an individual's own condition, their opponent's condition or a combination of the two. The use of chemical information to assess the quality of rivals has been underestimated despite its central role in the regulation of social interactions in many taxa. Here, we studied pairwise contests between founding queens of the ant Lasius niger to investigate whether the decision to engage in agonistic interactions relies on self-assessment or mutual assessment. Queens modulated their aggressive behaviours depending on both their own status and their opponent's status. We found no influence of lipid stores or size on the onset of fights. However, differences in cuticular chemical signatures linked to fertility status accurately predicted the probability of behaving aggressively in pairs. Our study thus suggests that ant queens could rely on mutual assessment via chemical cues to make informed decisions about fight initiation.

  6. Abiotic mediation of a mutualism drives herbivore abundance.

    PubMed

    Mooney, Emily H; Phillips, Joseph S; Tillberg, Chadwick V; Sandrow, Cheryl; Nelson, Annika S; Mooney, Kailen A

    2016-01-01

    Species abundance is typically determined by the abiotic environment, but the extent to which such effects occur through the mediation of biotic interactions, including mutualisms, is unknown. We explored how light environment (open meadow vs. shaded understory) mediates the abundance and ant tending of the aphid Aphis helianthi feeding on the herb Ligusticum porteri. Yearly surveys consistently found aphids to be more than 17-fold more abundant on open meadow plants than on shaded understory plants. Manipulations demonstrated that this abundance pattern was not due to the direct effects of light environment on aphid performance, or indirectly through host plant quality or the effects of predators. Instead, open meadows had higher ant abundance and per capita rates of aphid tending and, accordingly, ants increased aphid population growth in meadow but not understory environments. The abiotic environment thus drives the abundance of this herbivore exclusively through the mediation of a protection mutualism.

  7. Mutualism supports biodiversity when the direct competition is weak

    NASA Astrophysics Data System (ADS)

    Pascual-García, Alberto; Bastolla, Ugo

    2017-02-01

    A key question of theoretical ecology is which properties of ecosystems favour their stability and help maintaining biodiversity. This question recently reconsidered mutualistic systems, generating intense controversy about the role of mutualistic interactions and their network architecture. Here we show analytically and verify with simulations that reducing the effective interspecific competition and the propagation of perturbations positively influences structural stability against environmental perturbations, enhancing persistence. Noteworthy, mutualism reduces the effective interspecific competition only when the direct interspecific competition is weaker than a critical value. This critical competition is in almost all cases larger in pollinator networks than in random networks with the same connectance. Highly connected mutualistic networks reduce the propagation of environmental perturbations, a mechanism reminiscent of MacArthur's proposal that ecosystem complexity enhances stability. Our analytic framework rationalizes previous contradictory results, and it gives valuable insight on the complex relationship between mutualism and biodiversity.

  8. Driven diffusive systems with mutually interactive Langmuir kinetics

    NASA Astrophysics Data System (ADS)

    Vuijk, H. D.; Rens, R.; Vahabi, M.; MacKintosh, F. C.; Sharma, A.

    2015-03-01

    We investigate the simple one-dimensional driven model, the totally asymmetric exclusion process, coupled to mutually interactive Langmuir kinetics. This model is motivated by recent studies on clustering of motor proteins on microtubules. In the proposed model, the attachment and detachment rates of a particle are modified depending upon the occupancy of neighboring sites. We first obtain continuum mean-field equations and in certain limiting cases obtain analytic solutions. We show how mutual interactions increase (decrease) the effects of boundaries on the phase behavior of the model. We perform Monte Carlo simulations and demonstrate that our analytical approximations are in good agreement with the numerics over a wide range of model parameters. We present phase diagrams over a selective range of parameters.

  9. Bias reduction in the estimation of mutual information.

    PubMed

    Zhu, Jie; Bellanger, Jean-Jacques; Shu, Huazhong; Yang, Chunfeng; Le Bouquin Jeannès, Régine

    2014-11-01

    This paper deals with the control of bias estimation when estimating mutual information from a nonparametric approach. We focus on continuously distributed random data and the estimators we developed are based on a nonparametric k-nearest-neighbor approach for arbitrary metrics. Using a multidimensional Taylor series expansion, a general relationship between the estimation error bias and the neighboring size for the plug-in entropy estimator is established without any assumption on the data for two different norms. The theoretical analysis based on the maximum norm developed coincides with the experimental results drawn from numerical tests made by Kraskov et al. [Phys. Rev. E 69, 066138 (2004)PLEEE81539-375510.1103/PhysRevE.69.066138]. To further validate the novel relation, a weighted linear combination of distinct mutual information estimators is proposed and, using simulated signals, the comparison of different strategies allows for corroborating the theoretical analysis.

  10. Bias reduction in the estimation of mutual information

    NASA Astrophysics Data System (ADS)

    Zhu, Jie; Bellanger, Jean-Jacques; Shu, Huazhong; Yang, Chunfeng; Le Bouquin Jeannès, Régine

    2014-11-01

    This paper deals with the control of bias estimation when estimating mutual information from a nonparametric approach. We focus on continuously distributed random data and the estimators we developed are based on a nonparametric k -nearest-neighbor approach for arbitrary metrics. Using a multidimensional Taylor series expansion, a general relationship between the estimation error bias and the neighboring size for the plug-in entropy estimator is established without any assumption on the data for two different norms. The theoretical analysis based on the maximum norm developed coincides with the experimental results drawn from numerical tests made by Kraskov et al. [Phys. Rev. E 69, 066138 (2004), 10.1103/PhysRevE.69.066138]. To further validate the novel relation, a weighted linear combination of distinct mutual information estimators is proposed and, using simulated signals, the comparison of different strategies allows for corroborating the theoretical analysis.

  11. Qualitative teamwork issues and strategies: coordination through mutual adjustment.

    PubMed

    Hall, Wendy A; Long, Bonita; Bermbach, Nicole; Jordan, Sharalyn; Patterson, Kathryn

    2005-03-01

    Multidisciplinary research teams that include faculty, students, and volunteers can be challenging and enriching for all participants. Although such teams are becoming commonplace, minimal guidance is available about strategies to enhance team effectiveness. In this article, the authors highlight strategies to guide qualitative teamwork through coordination of team members and tasks based on mutual adjustment. Using a grounded theory exemplar, they focus on issues of (a) building the team, (b) developing reflexivity and theoretical sensitivity, (c) tackling analytic and methodological procedures, and (d) developing dissemination guidelines. Sharing information, articulating project goals and elements, acknowledging variation in individual goals, and engaging in reciprocity and respectful collaboration are key elements of mutual adjustment. The authors summarize conclusions about the costs and benefits of the process.

  12. An Efficient Algorithm for Direction Finding against Unknown Mutual Coupling

    PubMed Central

    Wang, Weijiang; Ren, Shiwei; Ding, Yingtao; Wang, Haoyu

    2014-01-01

    In this paper, an algorithm of direction finding is proposed in the presence of unknown mutual coupling. The preliminary direction of arrival (DOA) is estimated using the whole array for high resolution. Further refinement can then be conducted by estimating the angularly dependent coefficients (ADCs) with the subspace theory. The mutual coupling coefficients are finally determined by solving the least squares problem with all of the ADCs utilized without discarding any. Simulation results show that the proposed method can achieve better performance at a low signal-to-noise ratio (SNR) with a small-sized array and is more robust, compared with the similar processes employing the initial DOA estimation and further improvement iteratively. PMID:25347587

  13. An efficient algorithm for direction finding against unknown mutual coupling.

    PubMed

    Wang, Weijiang; Ren, Shiwei; Ding, Yingtao; Wang, Haoyu

    2014-10-24

    In this paper, an algorithm of direction finding is proposed in the presence of unknown mutual coupling. The preliminary direction of arrival (DOA) is estimated using the whole array for high resolution. Further refinement can then be conducted by estimating the angularly dependent coefficients (ADCs) with the subspace theory. The mutual coupling coefficients are finally determined by solving the least squares problem with all of the ADCs utilized without discarding any. Simulation results show that the proposed method can achieve better performance at a low signal-to-noise ratio (SNR) with a small-sized array and is more robust, compared with the similar processes employing the initial DOA estimation and further improvement iteratively.

  14. Circumstances for Pluto-Charon mutual events in 1987

    NASA Technical Reports Server (NTRS)

    Tholen, David J.; Buie, Marc W.; Swift, Catherine E.

    1987-01-01

    Circumstances are tabulated for 88 Pluto-Charon mutual events occurring during the 1987 opposition. Charon is predicted to be completely obscured either by Pluto or Pluto's shadow during each passage behind Pluto during this opposition, providing several opportunities to study Pluto uncontaminated by the light of Charon. The duration of these total events is predicted to be from 32 to 79 min. The mutual-event season is now expected to conclude during the 1990 opposition. Two new stars have been selected as comparison stars for events occurring prior to opposition in 1987. Standardization of the primary comparison stars used in 1985 and 1986 has yielded the following magnitudes: B = 12.6044 + or - 0.0015 and V = 11.7956 + or - 0.0017 (1985 Primary); B = 13.1238 + or 0.0008 and V = 12.3885 + or - 0.0014 (1986 Primary).

  15. Role of mutual punishment in the snowdrift game

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wang, Zhen

    2015-09-01

    The effects of punishment on cooperation have drawn increasing attention. In this paper, we propose a new mechanism of punishment, in which an individual will punish each neighbor if their strategies are different, and vice versa. We incorporate the mutual punishment into the snowdrift game. Results for well-mixed and structured populations have shown that, for no punishment or small values of punishment fine, the fraction of cooperators continuously decreases with the temptation to defect. However, for large values of punishment fine, there exists an abrupt transition point, at which the fraction of cooperators suddenly drops from 1 to 0. Compared to no punishment, mutual punishment promotes cooperation when the temptation to defect is small but inhibits cooperation when the temptation to defect is large. For weak (strong) temptation to defect, the cooperation level increases (decreases) with the punishment fine. For moderate temptation to defect, there exists an optimal value of the punishment fine that leads to the highest cooperation level.

  16. Integrated semiconductor twin-microdisk laser under mutually optical injection

    SciTech Connect

    Zou, Ling-Xiu; Liu, Bo-Wen; Lv, Xiao-Meng; Yang, Yue-De; Xiao, Jin-Long; Huang, Yong-Zhen

    2015-05-11

    We experimentally study the characteristics of an integrated semiconductor twin-microdisk laser under mutually optical injection through a connected optical waveguide. Based on the lasing spectra, four-wave mixing, injection locking, and period-two oscillation states are observed due to the mutually optical injection by adjusting the injected currents applied to the two microdisks. The enhanced 3 dB bandwidth is realized for the microdisk laser at the injection locking state, and photonic microwave is obtained from the electrode of the microdisk laser under the period-two oscillation state. The plentifully dynamical states similar as semiconductor lasers subject to external optical injection are realized due to strong optical interaction between the two microdisks.

  17. Self-mixing interferometry with mutual independent orthogonal polarized light.

    PubMed

    Zhang, Shaohui; Zhang, Shulian; Tan, Yidong; Sun, Liqun

    2016-02-15

    A self-mixing interferometry with mutual independent orthogonal polarized light is introduced. Its most important feature is that two mutual independent orthogonal lights are used as measuring and reference light. Frequency shifting and polarization multiplexing technologies are used in the proposed optical system. Phase variation of the two orthogonal polarized beams is simultaneously measured through heterodyne demodulation with a lock-in amplifier. The phase difference of the orthogonal polarized light accurately reflects the target displacement. The target in this system is a non-cooperative object which is different from a traditional Michelson interferometer. The primary experimental results show that this kind of self-mixing interferometry is very feasible. Under typical room conditions, the system's short-term resolution is better than 2 nm.

  18. Breakdown and delayed cospeciation in the arbuscular mycorrhizal mutualism

    PubMed Central

    Merckx, Vincent; Bidartondo, Martin I

    2008-01-01

    The ancient arbuscular mycorrhizal association between the vast majority of plants and the fungal phylum Glomeromycota is a dominant nutritional mutualism worldwide. In the mycorrhizal mutualism, plants exchange photosynthesized carbohydrates for mineral nutrients acquired by fungi from the soil. This widespread cooperative arrangement is broken by ‘cheater’ plant species that lack the ability to photosynthesize and thus become dependent upon three-partite linkages (cheater–fungus–photosynthetic plant). Using the first fine-level coevolutionary analysis of mycorrhizas, we show that extreme fidelity towards fungi has led cheater plants to lengthy evolutionary codiversification. Remarkably, the plants' evolutionary history closely mirrors that of their considerably older mycorrhizal fungi. This demonstrates that one of the most diffuse mutualistic networks is vulnerable to the emergence, persistence and speciation of highly specific cheaters. PMID:18270159

  19. Extracting an entanglement signature from only classical mutual information

    SciTech Connect

    Starling, David J.; Howell, John C.; Broadbent, Curtis J.

    2011-09-15

    We introduce a quantity which is formed using classical notions of mutual information and which is computed using the results of projective measurements. This quantity constitutes a sufficient condition for entanglement and represents the amount of information that can be extracted from a bipartite system for spacelike separated observers. In addition to discussion, we provide simulations as well as experimental results for the singlet and maximally correlated mixed states.

  20. Information properties of a hologram of mutually conjugate waves

    SciTech Connect

    Rubanov, A.S.; Serebryakova, L.M.

    1995-12-01

    A theoretical study of information properties of a correlation response to a fragment of an image of a thin referenceless hologram of mutually conjugate waves that is recorded with a phase-conjugating (PC) mirror is reported. It is shown that this hologram reconstructs a full image in reflected light and can be used as an associative storage device and as a selective PC mirror. 7 refs., 1 fig.

  1. Modeling of Mutual Anion-Cation Neutralization Processes

    DTIC Science & Technology

    2011-07-01

    understanding of elementary processes in plasma chemistry, conducted jointly with the research group of Dr. A. A. Viggiano at the AFRL and supported by...basic processes in the dynamics of electron-catalyzed mutual neutralization of plasmas . He has arrived at a better quantitative understanding of...Chemical Kinetics, Plasma Chemistry 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18, NUMBER OF PAGES 9 19a. NAME OF

  2. Resolving Dynamical Properties for Four 2007 Uranus Satellite Mutual Events

    NASA Astrophysics Data System (ADS)

    Miller, Charles; Chanover, N. J.

    2008-09-01

    Uranus reached equinox in December 2007, an event that occurs once every 42 years. The 2007 equinox provided an opportunity to observe a number of mutual satellite encounters - occultations and eclipses - as the equatorial plane of Uranus pointed at Earth. The mean orbital motions of the Uranian satellites, specifically their relative mean anomalies and relative velocities, dictate the precise midpoint timing of an occultation. Likewise, the relative orbital inclinations of the interacting satellites determine the impact parameter of each event, which affects the magnitude drop. Therefore, identifying the precise midpoint timing and magnitude drop of mutual satellite encounters provides a check on the ephemerides used to predict these mutual events, which in turn places constraints on the satellite orbital models used to derive the ephemerides. We observed four Uranus satellite mutual encounters - occultations of Titania and Ariel by Umbriel in August 2007, and eclipses of Ariel by Umbriel and of Umbriel by Ariel in December 2007. We observed all events using the Astrophysical Research Consortium's 3.5 meter telescope at the Apache Point Observatory in Sunspot, NM with the Agile high-speed time-series photometer and a Johnson I-band filter. We obtained light curves with a time resolution of 0.5 second for both occultations and 1.0 second for both eclipses. We fit data from simulated occultations and eclipses to our light curves to determine values for four free parameters - event midpoint, relative albedo, relative velocity, and impact parameter - and compared them to predicted values. We find that all four midpoints occurred later than predicted, with delays ranging from 21.2 to 37.6 seconds. We present our results and discuss our occultation and eclipse models. This study was funded through the NMSU 21st Space and Aerospace Research Cluster Graduate Fellowship.

  3. Exometabolomics Assisted Design and Validation of Synthetic Obligate Mutualism.

    PubMed

    Kosina, Suzanne M; Danielewicz, Megan A; Mohammed, Mujahid; Ray, Jayashree; Suh, Yumi; Yilmaz, Suzan; Singh, Anup K; Arkin, Adam P; Deutschbauer, Adam M; Northen, Trent R

    2016-07-15

    Synthetic microbial ecology has the potential to enhance the productivity and resiliency of biotechnology processes compared to approaches using single isolates. Engineering microbial consortia is challenging; however, one approach that has attracted significant attention is the creation of synthetic obligate mutualism using auxotrophic mutants that depend on each other for exchange or cross-feeding of metabolites. Here, we describe the integration of mutant library fitness profiling with mass spectrometry based exometabolomics as a method for constructing synthetic mutualism based on cross-feeding. Two industrially important species lacking known ecological interactions, Zymomonas mobilis and Escherichia coli, were selected as the test species. Amino acid exometabolites identified in the spent medium of Z. mobilis were used to select three corresponding E. coli auxotrophs (proA, pheA and IlvA), as potential E. coli counterparts for the coculture. A pooled mutant fitness assay with a Z. mobilis transposon mutant library was used to identify mutants with improved growth in the presence of E. coli. An auxotroph mutant in a gene (ZMO0748) with sequence similarity to cysteine synthase A (cysK), was selected as the Z. mobilis counterpart for the coculture. Exometabolomic analysis of spent E. coli medium identified glutathione related metabolites as potentially available for rescue of the Z. mobilis cysteine synthase mutant. Three sets of cocultures between the Z. mobilis auxotroph and each of the three E. coli auxotrophs were monitored by optical density for growth and analyzed by flow cytometry to confirm high cell counts for each species. Taken together, our methods provide a technological framework for creating synthetic mutualisms combining existing screening based methods and exometabolomics for both the selection of obligate mutualism partners and elucidation of metabolites involved in auxotroph rescue.

  4. Evolution of mutualism between globeflowers and their pollinating flies.

    PubMed

    Ferdy, Jean-Baptiste; Després, Laurence; Godelle, Bernard

    2002-07-21

    Plant/seed-eater pollinators mutualisms involve a plant pollinated by an insect whose larvae develop by eating a fraction of host-plant seeds. The outcome of the interaction therefore depends on the number of ovules fertilized by adult visits and the number of seeds destroyed by larvae. Among the very few cases of such mutualisms reported so far is the globeflower-globeflower flies mutualism, which is unique in that it involves several congeneric fly species (Chiastocheta genus) coexisting within a single host-plant species, Trollius europaeus. These species exhibit contrasted oviposition behaviors resulting in a more or less beneficial outcome for the plant. We designed an adaptive dynamics model to investigate how morphological traits of globeflower could affect the evolution of oviposition in its pollinating flies. Three fly traits (flower age at oviposition, clutch size and the level of avoidance of already parasitized flowers) and one plant trait (closed or open corolla) were examined. Whatever the shape of the flower, evolutionary branching occurs between early and late ovipositing flies, driven by strong competition among larvae within a fruit. Once this branching occurred, the closed shape of the corolla is likely to offer a better protection to eggs of early but not of late ovipositing flies. The difference in egg survival results in higher competition among early larvae and thus selects for decreased clutch size in early flies. This can be seen as a first step in the evolution of a mutualistic behavior. The prediction of our model fits field observations of fly behavior, giving theoretical support to the hypothesis of fly sympatric speciation within its host plant. Moreover, flower closed globe shape can be positively selected in globeflowers as it results in a reduction of parasitism strength. This last evolution therefore leads to a stable mutualism between globeflowers and globeflower flies.

  5. Finite difference time domain calculations of antenna mutual coupling

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    The Finite Difference Time Domain (FDTD) technique was applied to a wide variety of electromagnetic analysis problems, including shielding and scattering. However, the method has not been exclusively applied to antennas. Here, calculations of self and mutual admittances between wire antennas are made using FDTD and compared with results obtained during the method of moments. The agreement is quite good, indicating the possibilities for FDTD application to antenna impedance and coupling.

  6. Finite difference time domain calculations of antenna mutual coupling

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    The Finite Difference Time Domain (FDTD) technique has been applied to a wide variety of electromagnetic analysis problems, including shielding and scattering. However, the method has not been extensively applied to antennas. In this short paper calculations of self and mutual admittances between wire antennas are made using FDTD and compared with results obtained using the Method of Moments. The agreement is quite good, indicating the possibilities for FDTD application to antenna impedance and coupling.

  7. Jupiter's Galilean satellites mutual events as a teaching tool

    NASA Astrophysics Data System (ADS)

    Rojas, J. F.; Sanchez-Lavega, A.

    2015-10-01

    We present a set of observations of the mutual phenomena (occultations and eclipses) between Jupiter's Galilean satellites in 2014 and 2015 obtained with a Celestron 11 telescope from the Aula EspaZio Gela at E.T.S.I. - UPV/EHU. These observations are used as a practical teaching tool for photometry and astrodynamics in different matters of the Master in Space Science and Technology UPV/EHU.

  8. Observation and Analysis of Jovian and Saturnian Satellite Mutual Events

    NASA Technical Reports Server (NTRS)

    Tholen, David J.

    2001-01-01

    The main goal of this research was to acquire high time resolution photometry of satellite-satellite mutual events during the equatorial plane crossing for Saturn in 1995 and Jupiter in 1997. The data would be used to improve the orbits of the Saturnian satellites to support Cassini mission requirements, and also to monitor the secular acceleration of Io's orbit to compare with heat flow measurements.

  9. Extracting an entanglement signature from only classical mutual information

    NASA Astrophysics Data System (ADS)

    Starling, David J.; Broadbent, Curtis J.; Howell, John C.

    2011-09-01

    We introduce a quantity which is formed using classical notions of mutual information and which is computed using the results of projective measurements. This quantity constitutes a sufficient condition for entanglement and represents the amount of information that can be extracted from a bipartite system for spacelike separated observers. In addition to discussion, we provide simulations as well as experimental results for the singlet and maximally correlated mixed states.

  10. 75 FR 28665 - Kinetics Mutual Funds, Inc., et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... COMMISSION Kinetics Mutual Funds, Inc., et al.; Notice of Application May 17, 2010. AGENCY: Securities and... the Act to invest in certain financial instruments. ] APPLICANTS: Kinetics Mutual Funds, Inc. (``Company''), Kinetics Portfolios Trust (``Trust''), Kinetics Asset Management, Inc. (``Adviser''), and...

  11. Social Mobilization.

    PubMed

    Rogers, Todd; Goldstein, Noah J; Fox, Craig R

    2017-09-25

    This article reviews research from several behavioral disciplines to derive strategies for prompting people to perform behaviors that are individually costly and provide negligible individual or social benefits but are meaningful when performed by a large number of individuals. Whereas the term social influence encompasses all the ways in which people influence other people, social mobilization refers specifically to principles that can be used to influence a large number of individuals to participate in an activity. The motivational force of social mobilization is amplified by the fact that others benefit from the encouraged behaviors, and its overall impact is enhanced by the fact that people are embedded within social networks. This article may be useful to those interested in the provision of public goods, collective action, and prosocial behavior, and we give special attention to field experiments on election participation, environmentally sustainable behaviors, and charitable giving. Expected final online publication date for the Annual Review of Psychology Volume 69 is January 4, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  12. Mobile Transporter

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Space Shuttle Atlantis, STS-110 mission, deployed this railcar, called the Mobile Transporter, and an initial 43-foot section of track, the S0 (S-zero) truss, preparing the International Space Station (ISS) for future spacewalks. The first railroad in space, the Mobile Transporter will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The 27,000-pound S0 truss is the first of 9 segments that will make up the Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. The Space Shuttle Orbiter Atlantis, STS-110 mission, was launched April 8, 2002 and returned to Earth April 19, 2002. STS-110's Extravehicular Activity (EVA) marked the first use of the Station's robotic arm to maneuver spacewalkers around the Station.

  13. Synchronization in human musical rhythms and mutually interacting complex systems

    PubMed Central

    Hennig, Holger

    2014-01-01

    Though the music produced by an ensemble is influenced by multiple factors, including musical genre, musician skill, and individual interpretation, rhythmic synchronization is at the foundation of musical interaction. Here, we study the statistical nature of the mutual interaction between two humans synchronizing rhythms. We find that the interbeat intervals of both laypeople and professional musicians exhibit scale-free (power law) cross-correlations. Surprisingly, the next beat to be played by one person is dependent on the entire history of the other person’s interbeat intervals on timescales up to several minutes. To understand this finding, we propose a general stochastic model for mutually interacting complex systems, which suggests a physiologically motivated explanation for the occurrence of scale-free cross-correlations. We show that the observed long-term memory phenomenon in rhythmic synchronization can be imitated by fractal coupling of separately recorded or synthesized audio tracks and thus applied in electronic music. Though this study provides an understanding of fundamental characteristics of timing and synchronization at the interbrain level, the mutually interacting complex systems model may also be applied to study the dynamics of other complex systems where scale-free cross-correlations have been observed, including econophysics, physiological time series, and collective behavior of animal flocks. PMID:25114228

  14. Synchronization in human musical rhythms and mutually interacting complex systems.

    PubMed

    Hennig, Holger

    2014-09-09

    Though the music produced by an ensemble is influenced by multiple factors, including musical genre, musician skill, and individual interpretation, rhythmic synchronization is at the foundation of musical interaction. Here, we study the statistical nature of the mutual interaction between two humans synchronizing rhythms. We find that the interbeat intervals of both laypeople and professional musicians exhibit scale-free (power law) cross-correlations. Surprisingly, the next beat to be played by one person is dependent on the entire history of the other person's interbeat intervals on timescales up to several minutes. To understand this finding, we propose a general stochastic model for mutually interacting complex systems, which suggests a physiologically motivated explanation for the occurrence of scale-free cross-correlations. We show that the observed long-term memory phenomenon in rhythmic synchronization can be imitated by fractal coupling of separately recorded or synthesized audio tracks and thus applied in electronic music. Though this study provides an understanding of fundamental characteristics of timing and synchronization at the interbrain level, the mutually interacting complex systems model may also be applied to study the dynamics of other complex systems where scale-free cross-correlations have been observed, including econophysics, physiological time series, and collective behavior of animal flocks.

  15. Stability of an intraguild predation system with mutual predation

    NASA Astrophysics Data System (ADS)

    Wang, Yuanshi; DeAngelis, Donald L.

    2016-04-01

    We examine intraguild predation (IGP), in which species both compete for resources or space and prey on each other. The IGP system is modeled here by a lattice gas model of the mean-field theory. First, we consider the IGP system of one species in which individuals of the same species cannibalize each other. The dynamical behavior of the model demonstrates a mechanism by which the intraspecific predation promotes persistence of the species. Then we consider the IGP system of two species with mutual predation. Global dynamics of the model exhibit basic properties of IGP: (i) When both species' efficiencies in converting the consumptions into fitness are large, the outcome of their interaction is mutualistic in form and the IGP promotes persistence of both species. (ii) When one species' efficiency is large but the other's is small, the interaction outcomes become parasitic in nature, in which an obligate species can survive through the mutual predation with a facultative one. (iii) When both species' efficiencies are small, the interaction outcomes are competitive in nature and the IGP leads to extinction of one of the species. A novel result of this work is that varying one parameter or population density of the species can lead to transition of interaction outcomes between mutualism, parasitism and competition. On the other hand, dynamics of the models demonstrate that over-predation or under-predation will result in extinction of one/both species, while intermediate predation is favorable under certain parameter ranges.

  16. Part mutual information for quantifying direct associations in networks

    PubMed Central

    Zhao, Juan; Zhou, Yiwei; Zhang, Xiujun; Chen, Luonan

    2016-01-01

    Quantitatively identifying direct dependencies between variables is an important task in data analysis, in particular for reconstructing various types of networks and causal relations in science and engineering. One of the most widely used criteria is partial correlation, but it can only measure linearly direct association and miss nonlinear associations. However, based on conditional independence, conditional mutual information (CMI) is able to quantify nonlinearly direct relationships among variables from the observed data, superior to linear measures, but suffers from a serious problem of underestimation, in particular for those variables with tight associations in a network, which severely limits its applications. In this work, we propose a new concept, “partial independence,” with a new measure, “part mutual information” (PMI), which not only can overcome the problem of CMI but also retains the quantification properties of both mutual information (MI) and CMI. Specifically, we first defined PMI to measure nonlinearly direct dependencies between variables and then derived its relations with MI and CMI. Finally, we used a number of simulated data as benchmark examples to numerically demonstrate PMI features and further real gene expression data from Escherichia coli and yeast to reconstruct gene regulatory networks, which all validated the advantages of PMI for accurately quantifying nonlinearly direct associations in networks. PMID:27092000

  17. Feature Selection for Chemical Sensor Arrays Using Mutual Information

    PubMed Central

    Wang, X. Rosalind; Lizier, Joseph T.; Nowotny, Thomas; Berna, Amalia Z.; Prokopenko, Mikhail; Trowell, Stephen C.

    2014-01-01

    We address the problem of feature selection for classifying a diverse set of chemicals using an array of metal oxide sensors. Our aim is to evaluate a filter approach to feature selection with reference to previous work, which used a wrapper approach on the same data set, and established best features and upper bounds on classification performance. We selected feature sets that exhibit the maximal mutual information with the identity of the chemicals. The selected features closely match those found to perform well in the previous study using a wrapper approach to conduct an exhaustive search of all permitted feature combinations. By comparing the classification performance of support vector machines (using features selected by mutual information) with the performance observed in the previous study, we found that while our approach does not always give the maximum possible classification performance, it always selects features that achieve classification performance approaching the optimum obtained by exhaustive search. We performed further classification using the selected feature set with some common classifiers and found that, for the selected features, Bayesian Networks gave the best performance. Finally, we compared the observed classification performances with the performance of classifiers using randomly selected features. We found that the selected features consistently outperformed randomly selected features for all tested classifiers. The mutual information filter approach is therefore a computationally efficient method for selecting near optimal features for chemical sensor arrays. PMID:24595058

  18. Rethinking "mutualism" in diverse host-symbiont communities.

    PubMed

    Mushegian, Alexandra A; Ebert, Dieter

    2016-01-01

    While examples of bacteria benefiting eukaryotes are increasingly documented, studies examining effects of eukaryote hosts on microbial fitness are rare. Beneficial bacteria are often called "mutualistic" even if mutual reciprocity of benefits has not been demonstrated and despite the plausibility of other explanations for these microbes' beneficial effects on host fitness. Furthermore, beneficial bacteria often occur in diverse communities, making mutualism both empirically and conceptually difficult to demonstrate. We suggest reserving the terms "mutualism" and "parasitism" for pairwise interactions where the relationship is largely independent of other species and can be verified by measuring the fitness effect experienced by both partners. In hosts with diverse microbial communities, we propose re-formulating some of the essential questions of symbiosis research - e.g. concerning specificity, transmission mode, and common evolutionary fates - as questions of community ecology and ecosystem function, allowing important biological interactions to be investigated without making assumptions about reciprocity. Understanding the fitness of host-associated bacteria is a crucial component of investigations into the role of microbes in eukaryote evolution.

  19. Oscillatory dynamics in a bacterial cross-protection mutualism.

    PubMed

    Yurtsev, Eugene Anatoly; Conwill, Arolyn; Gore, Jeff

    2016-05-31

    Cooperation between microbes can enable microbial communities to survive in harsh environments. Enzymatic deactivation of antibiotics, a common mechanism of antibiotic resistance in bacteria, is a cooperative behavior that can allow resistant cells to protect sensitive cells from antibiotics. Understanding how bacterial populations survive antibiotic exposure is important both clinically and ecologically, yet the implications of cooperative antibiotic deactivation on the population and evolutionary dynamics remain poorly understood, particularly in the presence of more than one antibiotic. Here, we show that two Escherichia coli strains can form an effective cross-protection mutualism, protecting each other in the presence of two antibiotics (ampicillin and chloramphenicol) so that the coculture can survive in antibiotic concentrations that inhibit growth of either strain alone. Moreover, we find that daily dilutions of the coculture lead to large oscillations in the relative abundance of the two strains, with the ratio of abundances varying by nearly four orders of magnitude over the course of the 3-day period of the oscillation. At modest antibiotic concentrations, the mutualistic behavior enables long-term survival of the oscillating populations; however, at higher antibiotic concentrations, the oscillations destabilize the population, eventually leading to collapse. The two strains form a successful cross-protection mutualism without a period of coevolution, suggesting that similar mutualisms may arise during antibiotic treatment and in natural environments such as the soil.

  20. Dispersal Mutualism Incorporated into Large-Scale, Infrequent Disturbances.

    PubMed

    Parker, V Thomas

    2015-01-01

    Because of their influence on succession and other community interactions, large-scale, infrequent natural disturbances also should play a major role in mutualistic interactions. Using field data and experiments, I test whether mutualisms have been incorporated into large-scale wildfire by whether the outcomes of a mutualism depend on disturbance. In this study a seed dispersal mutualism is shown to depend on infrequent, large-scale disturbances. A dominant shrubland plant (Arctostaphylos species) produces seeds that make up a persistent soil seed bank and requires fire to germinate. In post-fire stands, I show that seedlings emerging from rodent caches dominate sites experiencing higher fire intensity. Field experiments show that rodents (Perimyscus californicus, P. boylii) do cache Arctostaphylos fruit and bury most seed caches to a sufficient depth to survive a killing heat pulse that a fire might drive into the soil. While the rodent dispersal and caching behavior itself has not changed compared to other habitats, the environmental transformation caused by wildfire converts the caching burial of seed from a dispersal process to a plant fire adaptive trait, and provides the context for stimulating subsequent life history evolution in the plant host.

  1. Long-range RNA pairings contribute to mutually exclusive splicing

    PubMed Central

    Yue, Yuan; Yang, Yun; Dai, Lanzhi; Cao, Guozheng; Chen, Ran; Hong, Weiling; Liu, Baoping; Shi, Yang; Meng, Yijun; Shi, Feng; Xiao, Mu; Jin, Yongfeng

    2016-01-01

    Mutually exclusive splicing is an important means of increasing the protein repertoire, by which the Down's syndrome cell adhesion molecule (Dscam) gene potentially generates 38,016 different isoforms in Drosophila melanogaster. However, the regulatory mechanisms remain obscure due to the complexity of the Dscam exon cluster. Here, we reveal a molecular model for the regulation of the mutually exclusive splicing of the serpent pre-mRNA based on competition between upstream and downstream RNA pairings. Such dual RNA pairings confer fine tuning of the inclusion of alternative exons. Moreover, we demonstrate that the splicing outcome of alternative exons is mediated in relative pairing strength-correlated mode. Combined comparative genomics analysis and experimental evidence revealed similar bidirectional structural architectures in exon clusters 4 and 9 of the Dscam gene. Our findings provide a novel mechanistic framework for the regulation of mutually exclusive splicing and may offer potentially applicable insights into long-range RNA–RNA interactions in gene regulatory networks. PMID:26554032

  2. Oscillatory dynamics in a bacterial cross-protection mutualism

    PubMed Central

    Yurtsev, Eugene Anatoly; Conwill, Arolyn; Gore, Jeff

    2016-01-01

    Cooperation between microbes can enable microbial communities to survive in harsh environments. Enzymatic deactivation of antibiotics, a common mechanism of antibiotic resistance in bacteria, is a cooperative behavior that can allow resistant cells to protect sensitive cells from antibiotics. Understanding how bacterial populations survive antibiotic exposure is important both clinically and ecologically, yet the implications of cooperative antibiotic deactivation on the population and evolutionary dynamics remain poorly understood, particularly in the presence of more than one antibiotic. Here, we show that two Escherichia coli strains can form an effective cross-protection mutualism, protecting each other in the presence of two antibiotics (ampicillin and chloramphenicol) so that the coculture can survive in antibiotic concentrations that inhibit growth of either strain alone. Moreover, we find that daily dilutions of the coculture lead to large oscillations in the relative abundance of the two strains, with the ratio of abundances varying by nearly four orders of magnitude over the course of the 3-day period of the oscillation. At modest antibiotic concentrations, the mutualistic behavior enables long-term survival of the oscillating populations; however, at higher antibiotic concentrations, the oscillations destabilize the population, eventually leading to collapse. The two strains form a successful cross-protection mutualism without a period of coevolution, suggesting that similar mutualisms may arise during antibiotic treatment and in natural environments such as the soil. PMID:27194723

  3. Basolateral amygdala lesions abolish mutual reward preferences in rats.

    PubMed

    Hernandez-Lallement, Julen; van Wingerden, Marijn; Schäble, Sandra; Kalenscher, Tobias

    2016-01-01

    In a recent study, we demonstrated that rats prefer mutual rewards in a Prosocial Choice Task. Here, employing the same task, we show that the integrity of basolateral amygdala was necessary for the expression of mutual reward preferences. Actor rats received bilateral excitotoxic (n=12) or sham lesions (n=10) targeting the basolateral amygdala and were subsequently tested in a Prosocial Choice Task where they could decide between rewarding ("Both Reward") or not rewarding a partner rat ("Own Reward"), either choice yielding identical reward to the actors themselves. To manipulate the social context and control for secondary reinforcement sources, actor rats were paired with either a partner rat (partner condition) or with an inanimate rat toy (toy condition). Sham-operated animals revealed a significant preference for the Both-Reward-option in the partner condition, but not in the toy condition. Amygdala-lesioned animals exhibited significantly lower Both-Reward preferences than the sham group in the partner but not in the toy condition, suggesting that basolateral amygdala was required for the expression of mutual reward preferences. Critically, in a reward magnitude discrimination task in the same experimental setup, both sham-operated and amygdala-lesioned animals preferred large over small rewards, suggesting that amygdala lesion effects were restricted to decision making in social contexts, leaving self-oriented behavior unaffected.

  4. Long-range RNA pairings contribute to mutually exclusive splicing.

    PubMed

    Yue, Yuan; Yang, Yun; Dai, Lanzhi; Cao, Guozheng; Chen, Ran; Hong, Weiling; Liu, Baoping; Shi, Yang; Meng, Yijun; Shi, Feng; Xiao, Mu; Jin, Yongfeng

    2016-01-01

    Mutually exclusive splicing is an important means of increasing the protein repertoire, by which the Down's syndrome cell adhesion molecule (Dscam) gene potentially generates 38,016 different isoforms in Drosophila melanogaster. However, the regulatory mechanisms remain obscure due to the complexity of the Dscam exon cluster. Here, we reveal a molecular model for the regulation of the mutually exclusive splicing of the serpent pre-mRNA based on competition between upstream and downstream RNA pairings. Such dual RNA pairings confer fine tuning of the inclusion of alternative exons. Moreover, we demonstrate that the splicing outcome of alternative exons is mediated in relative pairing strength-correlated mode. Combined comparative genomics analysis and experimental evidence revealed similar bidirectional structural architectures in exon clusters 4 and 9 of the Dscam gene. Our findings provide a novel mechanistic framework for the regulation of mutually exclusive splicing and may offer potentially applicable insights into long-range RNA-RNA interactions in gene regulatory networks. © 2015 Yue et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  5. The Evolution of Mutual Mate Choice under Direct Benefits.

    PubMed

    Courtiol, Alexandre; Etienne, Loïc; Feron, Romain; Godelle, Bernard; Rousset, François

    2016-11-01

    In nature, the intensity of mate choice (i.e., choosiness) is highly variable within and between sexes. Despite growing empirical evidence of male and/or mutual mate choice, theoretical investigations of the joint evolution of female and male choosiness are few. In addition, previous approaches have often assumed an absence of trade-off between the direct benefits per mating and the lower mating rate that results from being choosy. Here we model the joint evolution of female and male choosiness when it is solely ruled by this fundamental trade-off. We show that this trade-off can generate a diversity of stable combinations of choosiness. Mutual mate choice can evolve only if both females and males exhibit long latency after mating. Furthermore, we show that an increase in choosiness in one sex does not necessarily prevent the evolution of mutual mate choice; the outcome depends on details shaping the trade-off: the life history, the decision rule for mate choice, and how the fecundity of a pair is shaped by the quality of both individuals. Last, we discuss the power of the sensitivity of the relative searching time (i.e., of the proportion of a lifetime spent searching for mates) as a predictor of the joint evolution of choosiness.

  6. Using MEMo to discover mutual exclusivity modules in cancer.

    PubMed

    Ciriello, Giovanni; Cerami, Ethan; Aksoy, Bulent Arman; Sander, Chris; Schultz, Nikolaus

    2013-03-01

    Although individual tumors show surprisingly diverse genomic alterations, these events tend to occur in a limited number of pathways, and alterations that affect the same pathway tend to not co-occur in the same patient. While pathway analysis has been a powerful tool in cancer genomics, our knowledge of oncogenic pathway modules is incomplete. To systematically identify such modules, we have developed a novel method, Mutual Exclusivity Modules in Cancer (MEMo). The method searches and identifies modules characterized by three properties: (1) member genes are recurrently altered across a set of tumor samples; (2) member genes are known to or are likely to participate in the same biological process; and (3) alteration events within the modules are mutually exclusive. MEMo integrates multiple data types and maps genomic alterations to biological pathways. MEMo's mutual exclusivity uses a statistical model that preserves the number of alterations per gene and per sample. The MEMo software, source code and sample data sets are available for download at: http://cbio.mskcc.org/memo.

  7. Multiple occurrences of mutualism in the yucca moth lineage.

    PubMed Central

    Pellmyr, O; Thompson, J N

    1992-01-01

    The complex mutualism between yuccas and the moths that pollinate their flowers is regarded as one of the most obvious cases of coevolution. Studies of related genera show that at least two of the critical behavioral and life history traits suggested to have resulted from coevolved mutualism in yucca moths are plesiomorphic to the family. Another trait, oviposition into flowers, has evolved repeatedly within the family. One species with these traits, Greya politella, feeds on and pollinates plants of a different family, but pollination occurs through a different component of the oviposition behavior than in the yucca moths. Major differences compared with yucca moths and their hosts are that G. politella only passively pollinates its host and that copollinators often contribute to pollination. This analysis suggests that evolution of mutualism between yuccas and yucca moths may have required few behavioral and life history changes in the moths. The truly coevolved features of this interaction appear to be the evolution of active pollination by the moths, the associated morphological structures in the moths for carrying pollen, and the exclusion of copollinators by yuccas. Images PMID:11607287

  8. Yucca aloifolia (Asparagaceae) opts out of an obligate pollination mutualism.

    PubMed

    Rentsch, Jeremy D; Leebens-Mack, Jim

    2014-12-01

    • According to Cope's 'law of the unspecialized' highly dependent species interactions are 'evolutionary dead ends,' prone to extinction because reversion to more generalist interactions is thought to be unlikely. Cases of extreme specialization, such as those seen between obligate mutualists, are cast as evolutionarily inescapable, inevitably leading to extinction rather than diversification of participating species. The pollination mutualism between Yucca plants and yucca moths (Tegeticula and Parategeticula) would seem to be locked into such an obligate mutualism. Yucca aloifolia populations, however, can produce large numbers of fruit lacking moth oviposition scars. Here, we investigate the pollination ecology of Y. aloifolia, in search of the non-moth pollination of a Yucca species.• We perform pollinator exclusion studies on Yucca aloifolia and a sympatric yucca species, Y. filamentosa. We then perform postvisit exclusion treatments, an analysis of dissected fruits, and a fluorescent dye transfer experiment.• As expected, Yucca filamentosa plants set fruit only when inflorescences were exposed to crepuscular and nocturnal pollinating yucca moths. In contrast, good fruit set was observed when pollinators were excluded from Y. aloifolia inflorescences from dusk to dawn, and no fruit set was observed when pollinators were excluded during the day. Follow up experiments indicated that European honeybees (Apis mellifera) were passively yet effectively pollinating Y. aloifolia flowers.• These results indicate that even highly specialized mutualisms may not be entirely obligate interactions or evolutionary dead ends. © 2014 Botanical Society of America, Inc.

  9. Dispersal Mutualism Incorporated into Large-Scale, Infrequent Disturbances

    PubMed Central

    Parker, V. Thomas

    2015-01-01

    Because of their influence on succession and other community interactions, large-scale, infrequent natural disturbances also should play a major role in mutualistic interactions. Using field data and experiments, I test whether mutualisms have been incorporated into large-scale wildfire by whether the outcomes of a mutualism depend on disturbance. In this study a seed dispersal mutualism is shown to depend on infrequent, large-scale disturbances. A dominant shrubland plant (Arctostaphylos species) produces seeds that make up a persistent soil seed bank and requires fire to germinate. In post-fire stands, I show that seedlings emerging from rodent caches dominate sites experiencing higher fire intensity. Field experiments show that rodents (Perimyscus californicus, P. boylii) do cache Arctostaphylos fruit and bury most seed caches to a sufficient depth to survive a killing heat pulse that a fire might drive into the soil. While the rodent dispersal and caching behavior itself has not changed compared to other habitats, the environmental transformation caused by wildfire converts the caching burial of seed from a dispersal process to a plant fire adaptive trait, and provides the context for stimulating subsequent life history evolution in the plant host. PMID:26151560

  10. Hydrodynamics of rapidly rotating superfluid neutron stars with mutual friction

    NASA Astrophysics Data System (ADS)

    Passamonti, A.; Andersson, N.

    2011-05-01

    We study the hydrodynamics of superfluid neutron stars, focusing on the nature of the oscillation spectrum, the effect of mutual friction force on the oscillations and the spin-up phase of pulsar glitches. We linearize the dynamical equations of a Newtonian two-fluid model for rapidly rotating backgrounds. In the axisymmetric equilibrium configurations, the two-fluid components corotate and are in β-equilibrium. We use analytical equations of state that generate stratified and non-stratified stellar models, which enable us to study the coupling between the dynamical degrees of freedom of the system. By means of time-evolutions of the linearized dynamical equations, we determine the spectrum of axisymmetric and non-axisymmetric oscillation modes, accounting for the contribution of the gravitational potential perturbations, that is, without adopting the Cowling approximation. We study the mutual friction damping of the superfluid oscillations and consider the effects of the non-dissipative part of the mutual friction force on the mode frequencies. We also provide technical details and relevant tests for the hydrodynamical model of pulsar glitches discussed by Sidery, Passamonti & Andersson. In particular, we describe the method used to generate the initial data that mimic the pre-glitch state and derive the equations that are used to extract the gravitational-wave signal.

  11. Part mutual information for quantifying direct associations in networks.

    PubMed

    Zhao, Juan; Zhou, Yiwei; Zhang, Xiujun; Chen, Luonan

    2016-05-03

    Quantitatively identifying direct dependencies between variables is an important task in data analysis, in particular for reconstructing various types of networks and causal relations in science and engineering. One of the most widely used criteria is partial correlation, but it can only measure linearly direct association and miss nonlinear associations. However, based on conditional independence, conditional mutual information (CMI) is able to quantify nonlinearly direct relationships among variables from the observed data, superior to linear measures, but suffers from a serious problem of underestimation, in particular for those variables with tight associations in a network, which severely limits its applications. In this work, we propose a new concept, "partial independence," with a new measure, "part mutual information" (PMI), which not only can overcome the problem of CMI but also retains the quantification properties of both mutual information (MI) and CMI. Specifically, we first defined PMI to measure nonlinearly direct dependencies between variables and then derived its relations with MI and CMI. Finally, we used a number of simulated data as benchmark examples to numerically demonstrate PMI features and further real gene expression data from Escherichia coli and yeast to reconstruct gene regulatory networks, which all validated the advantages of PMI for accurately quantifying nonlinearly direct associations in networks.

  12. Neotropical mutualism between Acacia and Pseudomyrmex: phylogeny and divergence times.

    PubMed

    Gómez-Acevedo, Sandra; Rico-Arce, Lourdes; Delgado-Salinas, Alfonso; Magallón, Susana; Eguiarte, Luis E

    2010-07-01

    The interaction between Acacia and Pseudomyrmex is a textbook example of mutualism between ants and plants, nevertheless aspects of its evolutionary biology have not been formally explored. In this paper we analyze primarily the phylogenies of both New World Acacia and of their associated species of ants, and the geographic origin of this mutualism. Until now, there has been no molecular analysis of this relationship in terms of its origin and age. We analyzed three chloroplast markers (matK, psaB-rps14, and trnL-trnF) on a total of 70 taxa of legumes from the subfamily Mimosoideae, and two nuclear regions (long-wavelength rhodopsine and wingless) on a total of 43 taxa of ants from subfamily Pseudomyrmecinae. The monophyly of subgenus Acacia and within the New World lineages that of the myrmecophilous Acacia group was established. In addition, our results supported the monophyly of the genus Pseudomyrmex and of the associated acacia-ants P. ferrugineus group. Using Bayesian methods and calibration data, the estimated divergence times for the groups involved in the mutualism are: 5.44+/-1.93 My for the myrmecophilous acacias and 4.58+/-0.82 My for their associated ant species, implying that their relationship originated in Mesoamerica between the late Miocene to the middle Pliocene, with eventual diversification of both groups in Mexico. Copyright 2010 Elsevier Inc. All rights reserved.

  13. Gas transmission through microporous membranes

    NASA Astrophysics Data System (ADS)

    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

  14. A spatial model showing differences between juxtacrine and paracrine mutual oocyte-granulosa cells interactions.

    PubMed

    Saadeldin, Islam M; Elsayed, Asmaa; Kim, Su Jin; Moon, Joon Hu; Lee, Byeong Chun

    2015-02-01

    The bidirectional communication between oocytes and granulosa cells are mediated by several factors via a local feedback loop(s). The current model was carried out to study the spatial mutual interaction of porcine denuded oocytes and granulosa cells either in direct contact (juxtacrine) or paracrine co-culture using transwell system. Transwell 0.4 μm polyester membrane inserts were used to permit oocytes-granulosa cells paracrine communication with a distance of 2 mm between them in co-culture. Oocytes were cultured with granulosa cells in a defined basic maturation medium for 44 h. In results, oocyte secreted factors (OSFs; GDF9 and BMP15) temporal expression showed progressive decrement by the end of culture in case of direct contact with granulosa cells while it was increased progressively in the paracrine co-culture groups. However, oocytes that were cultured in direct contact showed a significant increase in blastocyst development after parthenogenetic activation than the paracrine co-cultured ones (20% vs. 11.5%, respectively). By the end of culture, granulosa cell count in direct contact showed a significant decrease than the indirect co-culture group (1.2 x 105 cell/mL vs. 2.1 x 10(5) cell/mL, respectively). Steroids (P4 and E2) and steriodogenesis enzymes mRNA levels showed significant temporal alterations either after 22 h and 44 h of IVM in both juxtacrine and paracrine co-culture systems (P ≤ 0.05). CX43 was much more highly expressed in the granulosa of the direct contact group than the indirect co-culture group. These results indicate the difference in mutual communication between oocytes and granulosa cells that were cocultured either in direct contact (juxtacrine) or with a short distance (paracrine) and propose a new paradigm to study different ovarian follicular cells interaction.

  15. 12 CFR 575.12 - Conversion or liquidation of mutual holding companies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... companies. 575.12 Section 575.12 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY MUTUAL HOLDING COMPANIES § 575.12 Conversion or liquidation of mutual holding companies. (a) Conversion—(1) Generally. A mutual holding company may convert to the stock form in accordance with the...

  16. 12 CFR 575.12 - Conversion or liquidation of mutual holding companies.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... companies. 575.12 Section 575.12 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY MUTUAL HOLDING COMPANIES § 575.12 Conversion or liquidation of mutual holding companies. (a) Conversion—(1) Generally. A mutual holding company may convert to the stock form in accordance with the...

  17. 12 CFR 575.12 - Conversion or liquidation of mutual holding companies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... companies. 575.12 Section 575.12 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY MUTUAL HOLDING COMPANIES § 575.12 Conversion or liquidation of mutual holding companies. (a) Conversion—(1) Generally. A mutual holding company may convert to the stock form in accordance with the...

  18. Parent-Child Mutuality in Early Childhood: Two Behavioral Genetic Studies.

    ERIC Educational Resources Information Center

    Deater-Deckard, Kirby; O'Connor, Thomas G.

    2000-01-01

    Used quantitative genetic design to examine between- and within-family variations and gene-environment processes in parent-child mutuality among 3-year-old identical and same-sex fraternal twins. Found that greater mutuality was associated with higher socioeconomic status. Moderate sibling similarity in parent-child mutuality was accounted for by…

  19. 24 CFR 203.420 - Nature of Mutual Mortgage Insurance Fund.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Nature of Mutual Mortgage Insurance Fund. 203.420 Section 203.420 Housing and Urban Development Regulations Relating to Housing and Urban... and Distributive Shares § 203.420 Nature of Mutual Mortgage Insurance Fund. The Mutual Mortgage...

  20. 24 CFR 203.420 - Nature of Mutual Mortgage Insurance Fund.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Nature of Mutual Mortgage Insurance Fund. 203.420 Section 203.420 Housing and Urban Development Regulations Relating to Housing and Urban... and Distributive Shares § 203.420 Nature of Mutual Mortgage Insurance Fund. The Mutual Mortgage...