WorldWideScience

Sample records for affinity influx v-atpase-dependent

  1. Conserved V-ATPase c subunit plays a role in plant growth by influencing V-ATPase-dependent endosomal trafficking.

    Science.gov (United States)

    Zhou, Aimin; Bu, Yuanyuan; Takano, Tetsuo; Zhang, Xinxin; Liu, Shenkui

    2016-01-01

    In plant cells, the vacuolar-type H(+)-ATPases (V-ATPase) are localized in the tonoplast, Golgi, trans-Golgi network and endosome. However, little is known about how V-ATPase influences plant growth, particularly with regard to the V-ATPase c subunit (VHA-c). Here, we characterized the function of a VHA-c gene from Puccinellia tenuiflora (PutVHA-c) in plant growth. Compared to the wild-type, transgenic plants overexpressing PutVHA-c in Arabidopsis thaliana exhibit better growth phenotypes in root length, fresh weight, plant height and silique number under the normal and salt stress conditions due to noticeably higher V-ATPase activity. Consistently, the Arabidopsis atvha-c5 mutant shows reduced V-ATPase activity and retarded plant growth. Furthermore, confocal and immunogold electron microscopy assays demonstrate that PutVHA-c is mainly localized to endosomal compartments. The treatment of concanamycin A (ConcA), a specific inhibitor of V-ATPases, leads to obvious aggregation of the endosomal compartments labelled with PutVHA-c-GFP. Moreover, ConcA treatment results in the abnormal localization of two plasma membrane (PM) marker proteins Pinformed 1 (AtPIN1) and regulator of G protein signalling-1 (AtRGS1). These findings suggest that the decrease in V-ATPase activity blocks endosomal trafficking. Taken together, our results strongly suggest that the PutVHA-c plays an important role in plant growth by influencing V-ATPase-dependent endosomal trafficking.

  2. V-ATPase-dependent luminal acidification is required for endocytic recycling of a yeast cell wall stress sensor, Wsc1p

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kazuma; Saito, Mayu; Nagashima, Makiko; Kojima, Ai; Nishinoaki, Show [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Junko Y., E-mail: yama_jun@aoni.waseda.jp [Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Jiro, E-mail: jtosiscb@rs.noda.tus.ac.jp [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan)

    2014-01-10

    Highlights: •A targeted genome screen identified 5 gene groups affecting Wsc1p recycling. •V-ATPase-dependent luminal acidification is required for Wsc1p recycling. •Activity of V-ATPase might be required for cargo recognition by the retromer complex. -- Abstract: Wsc1p is a major cell wall sensor protein localized at the polarized cell surface. The localization of Wsc1p is maintained by endocytosis and recycling from endosomes back to the cell surface, but changes to the vacuole when cells are subjected to heat stress. Exploiting this unique property of Wsc1p, we screened for yeast single-gene deletion mutants exhibiting defects in Wsc1p trafficking. By expressing 3GFP-tagged Wsc1p in mutants with deleted genes whose function is related to intracellular trafficking, we identified 5 gene groups affecting Wsc1p trafficking, impaired respectively in endocytic internalization, multivesicular body sorting, the GARP complex, endosomal maturation/vacuolar fusion, and V-ATPase. Interestingly, deletion of the VPH1 gene, encoding the V{sub o} subunit of vacuolar-type H{sup +}-ATPase (V-ATPase), led to mis-localization of Wsc1p from the plasma membrane to the vacuole. In addition, disruption of other V-ATPase subunits (vma mutants) also caused defects of Wsc1p trafficking and vacuolar acidification similar to those seen in the vph1Δ mutant. Moreover, we found that deletion of the VPS26 gene, encoding a subunit of the retromer complex, also caused a defect in Wsc1p recycling and mis-localization of Wsc1p to the vacuole. These findings clarified the previously unidentified Wsc1p recycling pathway and requirement of V-ATPase-dependent luminal acidification for Wsc1p recycling.

  3. ATP stimulates calcium influx in primary astrocyte cultures

    International Nuclear Information System (INIS)

    The effect of ATP and other purines on 45Ca uptake was studied in primary cultures of rat astrocytes. Treatment of the cells with ATP for 1 to 30 min brought about an increase in cellular 45Ca. Stimulation of calcium influx by ATP was investigated using a 90 sec exposure to 45Ca and over a concentration range of 0.1 nM to 3 mM; a biphasic dose-response curve was obtained with EC50 values of 0.3 nM and 9 uM, indicating the presence of low and high affinity purinergic binding sites. Similar levels of 45Ca influx at 90 sec were observed with ATP, ADP and adenosine (all at 100 uM). Prior treatment of the cultures with LaCl3 blocked the purine-induced 45Ca influx. These findings indicate that one pathway for calcium entry in astrocytes involves purinergic receptor-operated, calcium channels

  4. Calcium influx pathways in rat pancreatic ducts

    DEFF Research Database (Denmark)

    Hug, M J; Pahl, C; Novak, I

    1996-01-01

    A number of agonists increase intracellular Ca2+ activity, [Ca2+]i, in pancreatic ducts, but the influx/efflux pathways and intracellular Ca2+ stores in this epithelium are unknown. The aim of the present study was to characterise the Ca2+ influx pathways, especially their pH sensitivity, in nati...

  5. Gas-influx detection with MWD technology

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, T.M.; Grosso, D.S.; Wallace, S.N. (Teleco Oilfield Services (US))

    1991-12-01

    This paper describes a new gas-influx detection technique that monitors the acoustic responses of annular measurement-while-drilling (MWD) pulses to provide a rapid, early warning of the development of potential gas-kick situations. The technique has been evaluated in both water- and oil-based muds during about 40 gas-kick simulations at two full-scale testing facilities. Free gas is identified by amplitude attenuation and phase delay of MWD fundamentals and their harmonic frequencies. Detection is independent of influx location because the entire length of the annulus between the bit nozzles and a surface-pressure transducer is sampled. Detection of potential gas-kick situations generally occurred within minutes of influx initiation, before any significant gas expansion. Some tests also evaluated a downhole MWD mud-resistivity sensor. Results indicated that both these techniques, and particularly the pulse acoustics, can provide unequivocal confirmation of gas and an earlier warning of gas-kick situations than conventional kick- detection techniques.

  6. Calcium influx determines the muscular response to electrotransfer

    DEFF Research Database (Denmark)

    Møller, Pernille Højman; Brolin, Camilla; Gissel, Hanne

    2012-01-01

    expression analyses and histology, we showed a clear association between Ca(2+) influx and muscular response. Moderate Ca(2+) influx induced by HVLV pulses results in activation of pathways involved in immediate repair and hypertrophy. This response could be attenuated by intramuscular injection of EGTA...... reducing Ca(2+) influx. Larger Ca(2+) influx as induced by 8-HV pulses leads to muscle damage and muscle fiber regeneration through recruitment of satellite cells. The extent of Ca(2+) influx determines the muscular response to electrotransfer and, thus, the success of a given application. In the case...

  7. A cosmic dust influx model. III

    Science.gov (United States)

    Lebedinets, V. N.; Begkhanov, M.

    A model of cosmic dust influx is developed using results of radar and photographic studies of meteors and bolides, micrometeor impact data obtained during space missions, and the available experimental data on dust particles as small as 10 to the -17th g. It is shown, in particular, that particles of all sizes occurring above 30 km are mainly of meteor origin. Above 140 km, the earth atmosphere contains only primary cosmic particles of all sizes whose concentrations are equal to those observed in the interplanetary space but whose flux densities are twice as high. Above 30 km and below 100 km, the atmosphere contains primary micrometeor particles with masses less than 10 to the -8th g and particles of the same mass formed as a result of the fragmentation of large meteoric bodies.

  8. Influx of pyrophosphate ions into calvaria in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, M.W. (Univ. of Rochester, NY); Neuman, W.F.; Fleisch, H.

    1978-01-01

    The flux of /sup 32/P-labeled inorganic pyrophosphate (PP/sub i/) into bone was studied in vitro using Ussing chamber techniques and calvaria from newborn rat pups. Because insignificant hydrolysis and backflux of PP/sub i/ took place under experimental conditions, it was possible to study the penetration of bone membranes by PP/sub i/ unambiguously. At physiological concentrations, the influx was found to be linearly concentration dependent and to follow first order kinetics, apparently a simple diffusion process. In magnitude, the intrinsic constant for influx was found to be approximately one-half that of inorganic phosphate ions under comparable conditions.

  9. Affine Grassmann codes

    DEFF Research Database (Denmark)

    Høholdt, Tom; Beelen, Peter; Ghorpade, Sudhir Ramakant

    2010-01-01

    We consider a new class of linear codes, called affine Grassmann codes. These can be viewed as a variant of generalized Reed-Muller codes and are closely related to Grassmann codes.We determine the length, dimension, and the minimum distance of any affine Grassmann code. Moreover, we show that...... affine Grassmann codes have a large automorphism group and determine the number of minimum weight codewords....

  10. Calcium Influx of Mast Cells Is Inhibited by Aptamers Targeting the First Extracellular Domain of Orai1

    Science.gov (United States)

    Sun, Renshan; Yang, Yongqiang; Ran, Xinze; Yang, Tao

    2016-01-01

    Using the systematic evolution of ligands by exponential enrichment (SELEX) method, we identified oligonucleotides that bind to the first extracellular domain of the Orai1 protein with high affinities and high specificities. These ligands were isolated from a random single-strand DNA (ssDNA) library with 40 randomized sequence positions, using synthesized peptides with amino acid sequences identical to the first extracellular domain of the Orai1 protein as the targets for SELEX selection. Seven aptamers were obtained after 12 rounds of SELEX. An enzyme-linked oligonucleotide assay (ELONA) was performed to determine the affinities of the aptamers. Aptamer Y1 had the highest affinity (Kd = 1.72×10−8 mol/L) and was selected for functional experiments in mast cells. Using LAD2 cells with the human high-affinity IgE receptor and Ca2+ release activation channel (CRAC), we demonstrated that Aptamer Y1 blocked IgE-mediated β-hexosaminidase release from cells triggered by biotin-IgE and streptavidin. A specific binding assay showed that Aptamer Y1 not only bound the Orai1 peptide specifically but also that the Orai1 peptide did not bind significantly to other random oligonucleotide molecules. Furthermore, Aptamer Y1 regulation of intracellular Ca2+ mobilization was investigated by probing intracellular Ca2+ with a Fluo-4-AM fluorescent probe. We found that Aptamer Y1 inhibits Ca2+ influx into antigen-activated mast cells. These results indicate that the target of Aptamer Y1 in the degranulation pathway is upstream of Ca2+ influx. Therefore, these oligonucleotide agents represent a novel class of CRAC inhibitors that may be useful in the fight against allergic diseases. PMID:27390850

  11. Method and apparatus for borehole fluid influx detection

    Energy Technology Data Exchange (ETDEWEB)

    Grosso, D.S.

    1988-03-22

    This patent describes an apparatus for detection of fluid influx in a borehole in which a drill string is positioned, the drill string cooperating with the wall of the borehole to define an annulus, and in which drilling fluid is circulated from the surface through the interior of the drill string and into the annulus back to the surface, including: means for generating a coherent energy signal at a downhole location and propagation the signal as a primary signal in the drilling fluid in the drill string and as a secondary signal in the drilling fluid in the annulus; means for detecting the primary signal; means for detecting the secondary signal; means for measuring the difference between at least one selected parameter of the primary signal with the same selected parameter of the secondary signal, and means for determining changes in the measured difference between the selected parameter of the primary and secondary signals wherein fluid influx into the annulus is determined.

  12. Influx mechanisms in the embryonic and adult rat choroid plexus

    DEFF Research Database (Denmark)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Møllgård, Kjeld;

    2015-01-01

    The transcriptome of embryonic and adult rat lateral ventricular choroid plexus, using a combination of RNA-Sequencing and microarray data, was analyzed by functional groups of influx transporters, particularly solute carrier (SLC) transporters. RNA-Seq was performed at embryonic day (E) 15 and a...... studies suggests that the choroid plexus in embryonic brain plays a major role in supplying the developing brain with essential nutrients.......The transcriptome of embryonic and adult rat lateral ventricular choroid plexus, using a combination of RNA-Sequencing and microarray data, was analyzed by functional groups of influx transporters, particularly solute carrier (SLC) transporters. RNA-Seq was performed at embryonic day (E) 15 and...... in the adult plexus were expressed at higher levels than in embryos. These results are compared with earlier published physiological studies of amino acid and monocarboxylate transport in developing rodents. This comparison shows correlation of high expression of some transporters in the developing...

  13. Disruptions in AUX1-Dependent Auxin Influx Alter Hypocotyl Phototropism in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Bethany B.Stone; Emily L.Stowe-Evans; Reneé M.Harper; R.Brandon Celaya; Karin Ljung; G(o)ran Sandberg; Emmanuel Liscum

    2008-01-01

    Phototropism represents a differential growth response by which plant organs can respond adaptively to changes in the direction of incident light to optimize leaf/stem positioning for photosynthetic light capture and root growth orientation for water/nutrient acquisition. Studies over the past few years have identified a number of components in the signaling pathway(s) leading to development of phototropic curvatures in hypocotyls. These include the phototropin photoreceptors (phot1 and phot2) that perceive directional blue-light (BL) cues and then stimulate signaling,leading to relocalization of the plant hormone auxin, as well as the auxin response factor NPH4/ARF7 that responds to changes in local auxin concentrations to directly mediate expression of genes likely encoding proteins necessary for development of phototropic curvatures. While null mutations in NPH4/ARF7 condition an aphototropic response to unidirectional BL, seedlings carrying the same mutations recover BL-dependent phototropic responsiveness if coirradiated with red light (RL) or pre-treated with either ethylene. In the present study, we identify second-site enhancer mutations in the nph4 background that abrogate these recovery responses. One of these mutations-map1 ((m)odifier of (a)rf7 (p)henotypes (1))-was found to represent a missense allele of AUX1-a gene encoding a high-affinity auxin influx carrier previously associated with a number of root responses. Pharmocological studies and analyses of additional aux1 mutants confirmed that AUX1 functions as a modulator of hypocotyl phototropism. Moreover, we have found that the strength of dependence of hypocotyl phototropism on AUX1-mediated auxin influx is directly related to the auxin responsiveness of the seedling in question.

  14. Affine dynamics with torsion

    Energy Technology Data Exchange (ETDEWEB)

    Gueltekin, Kemal [Izmir Institute of Technology, Department of Physics, Izmir (Turkey)

    2016-03-15

    In this study, we give a thorough analysis of a general affine gravity with torsion. After a brief exposition of the affine gravities considered by Eddington and Schroedinger, we construct and analyze different affine gravities based on the determinants of the Ricci tensor, the torsion tensor, the Riemann tensor, and their combinations. In each case we reduce equations of motion to their simplest forms and give a detailed analysis of their solutions. Our analyses lead to the construction of the affine connection in terms of the curvature and torsion tensors. Our solutions of the dynamical equations show that the curvature tensors at different points are correlated via non-local, exponential rescaling factors determined by the torsion tensor. (orig.)

  15. Sodium influxes in internally perfused squid giant axon during voltage clamp.

    Science.gov (United States)

    Atwater, I; Bezanilla, F; Rojas, E

    1969-05-01

    1. An experimental method for measuring ionic influxes during voltage clamp in the giant axon of Dosidicus is described; the technique combines intracellular perfusion with a method for controlling membrane potential.2. Sodium influx determinations were carried out while applying rectangular pulses of membrane depolarization. The ratio ;measured sodium influx/computed ionic flux during the early current' is 0.92 +/- 0.12.3. Plots of measured sodium influx and computed ionic flux during the early current against membrane potential are very similar. There was evidence that the membrane potential at which the sodium influx vanishes is the potential at which the early current reverses. PMID:5767887

  16. Affine and degenerate affine BMW algebras: Actions on tensor space

    CERN Document Server

    Daugherty, Zajj; Virk, Rahbar

    2012-01-01

    The affine and degenerate affine Birman-Murakami-Wenzl (BMW) algebras arise naturally in the context of Schur-Weyl duality for orthogonal and symplectic quantum groups and Lie algebras, respectively. Cyclotomic BMW algebras, affine and cyclotomic Hecke algebras, and their degenerate versions are quotients. In this paper we explain how the affine and degenerate affine BMW algebras are tantalizers (tensor power centralizer algebras) by defining actions of the affine braid group and the degenerate affine braid algebra on tensor space and showing that, in important cases, these actions induce actions of the affine and degenerate affine BMW algebras. We then exploit the connection to quantum groups and Lie algebras to determine universal parameters for the affine and degenerate affine BMW algebras. Finally, we show that the universal parameters are central elements--the higher Casimir elements for orthogonal and symplectic enveloping algebras and quantum groups.

  17. Spectroscopic Measurement of Neutral Particle Influx Ratio on EAST

    International Nuclear Information System (INIS)

    The spectra of HeI (587.6 nm), Hα (656.28 nm) and Dα (656.1 nm) of the helium discharges as well as the normal deuterium discharges have been measured with two optical spectroscopic multi-channel analysis (OMA) systems on the experimental advanced superconducting tokamak (EAST). The influx ratio of the sum of H and D to He spectral lines and the influx ratio of H to D are given. In this way the ratio of hydrogen/deuterium ion (S/XB)H/D to (S/XB)He as well as (S/XB)H/D is not very sensitive to the variation in the edge density and temperature. The low-density helium discharges are operated in order to reduce the recycling hydrogen fluxes; however, the effect is not obvious. The possible reason is that the number of helium discharges is not enough and the content of hydrogen in the wall is still very abundant, which is caused by frequent wall conditionings and the vacuum leakage. The H/(H+D) ratio decreases quickly after one lithium coating and reduces to less than 10% using several accumulated lithium wall conditioning. It is found that the deposited He atoms on the carbon wall will remain at a low level after several D2 discharges.

  18. Affine stochastic mortality

    NARCIS (Netherlands)

    D.F. Schrager

    2006-01-01

    We propose a new model for stochastic mortality. The model is based on the literature on affine term structure models. It satisfies three important requirements for application in practice: analytical tractibility, clear interpretation of the factors and compatibility with financial option pricing m

  19. Relationship Between Accumulation and Influx of Pollutants in Highway Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    The paper discusses the long term mass balance of pollutants in highway ponds. The accumulations of five polycyclic aromatic hydrocarbons (PAHs) and six heavy metals have been measured in eight Danish detention ponds, which receive runoff from highways only. For each pollutant the accumulation has...... been compared to the long-term influx, estimated from short-term measurements of concentrations in highway runoff. The results show that a large proportion of the incoming heavy metals in short-term runoff events has accumulated in the ponds. This is not the case for the toxic organic compounds....... The results also show that the accumulation rates for the heavy metals depend significantly on the relative pond area (pond area divided by catchment area). The conclusion is that the mass balances of heavy metals and PAHs in highway ponds can be estimated with acceptable accuracy from a combination of short...

  20. Carbon influx studies in the main chamber of ASDEX Upgrade

    International Nuclear Information System (INIS)

    Carbon sources in the main chamber of ASDEX Upgrade, especially the 12 guard limiters at the low field side (LFS), were determined spectroscopically using recently installed lines of sight. Absolute photon fluxes were measured for spectral lines in the visible wavelength range referring to all spin systems of C+1 and C+2. A simple transport model for carbon enabled the simulation of the radial distribution of carbon radiation and the determination of the effective inverse photon efficiency, which was used for the evaluation of ion fluxes. The model also predicts the fraction of eroded particles that are transported out of the plasma before further ionization occurs. Comparison of the calculated losses with measurements showed good agreement in L-mode cases, whereas in H-mode cases the CIII/CII radiation ratio was too high by a factor 1.5. The contribution of each spin system to the ion flux was independently measured. For C+1 and C+2 the spin system distribution was found to be close to equilibrium. The line-of-sight-integrated photon fluxes were spatially separated for many lines of sight by Zeeman-analysis and differential measurements. This allowed us to determine the total influx from the high field side and LFS. Surprisingly, the carbon source at the inner heat shield was larger than the carbon influx from the limiter source at the LFS. This is very pronounced for the H-mode case investigated, where 60-80% of the carbon atoms emerge from the heat shield. This source is due to recycling or re-erosion of carbon, which probably originates from the limiters, because approximately 85% of the heat shield area consisted of tungsten coated tiles

  1. Carbon influx studies in the main chamber of ASDEX Upgrade

    Science.gov (United States)

    Pütterich, T.; Dux, R.; Gafert, J.; Kallenbach, A.; Neu, R.; Pugno, R.; Yoon, S. W.; ASDEX Upgrade Team

    2003-10-01

    Carbon sources in the main chamber of ASDEX Upgrade, especially the 12 guard limiters at the low field side (LFS), were determined spectroscopically using recently installed lines of sight. Absolute photon fluxes were measured for spectral lines in the visible wavelength range referring to all spin systems of C+1 and C+2. A simple transport model for carbon enabled the simulation of the radial distribution of carbon radiation and the determination of the effective inverse photon efficiency, which was used for the evaluation of ion fluxes. The model also predicts the fraction of eroded particles that are transported out of the plasma before further ionization occurs. Comparison of the calculated losses with measurements showed good agreement in L-mode cases, whereas in H-mode cases the CIII/CII radiation ratio was too high by a factor 1.5. The contribution of each spin system to the ion flux was independently measured. For C+1 and C+2 the spin system distribution was found to be close to equilibrium. The line-of-sight-integrated photon fluxes were spatially separated for many lines of sight by Zeeman-analysis and differential measurements. This allowed us to determine the total influx from the high field side and LFS. Surprisingly, the carbon source at the inner heatshield was larger than the carbon influx from the limiter source at the LFS. This is very pronounced for the H-mode case investigated, where 60-80% of the carbon atoms emerge from the heatshield. This source is due to recycling or re-erosion of carbon, which probably originates from the limiters, because ap85% of the heatshield area consisted of tungsten coated tiles.

  2. CO2 Biogenic vs Anthropogenic Sectoral Contribution for INFLUX

    Science.gov (United States)

    Lopez-Coto, I.; Prasad, K.; Hu, H.; Whetstone, J. R.; Miles, N. L.; Richardson, S.; Lauvaux, T.; Davis, K. J.; Turnbull, J. C.; Karion, A.; Sweeney, C.; Brewer, A.; Hardesty, M.; Cambaliza, M. O. L.; Shepson, P. B.; Patarasuk, R.; Gurney, K. R.

    2014-12-01

    The Indianapolis Flux Experiment (INFLUX) aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over an urban domain with high spatial and temporal resolution. This project is an experimental test bed which is intended to establish reliable methods for quantifying and validating GHG emissions independently of the inventory methods typically used for Measurement, Reporting and Verification (MRV) of pollution sources. Analyzing the contribution of different source types or sectors is a fundamental step in order to achieve an accuracy level desired for such MRV applications. This is especially challenging when attempting to determine anthropogenic emissions during the growing season since biological GHG fluxes reach a maximum at this time. To this end, the Weather Research and Forecasting Model (WRF-ARW) version 3.5.1 was used along with a modified version of the Green House Gases chemistry module for simulating the CO2 mole fraction transport during September and October 2013. Sectoral anthropogenic CO2 emissions were obtained from Hestia 2012 and from Vulcan 2002 beyond the spatial coverage of Hestia. Biogenic CO2 emissions were simulated by using an augmented version of the "Vegetation Photosynthesis and Respiration Model" (VPRM) included in WRF-CHEM. An implementation of the unconstrained nonlinear global optimization method of Nelder and Mead was employed to find the optimum values for the VPRM parameters for each vegetation category by using data from Ameriflux eddy covariance flux towers. Here we present a preliminary assessment of the relative contribution of biological vs sectoral anthropogenic CO2 fluxes on the INFLUX measurements network. The simulations are compared to tower and aircraft measurements that include trace gases with the capacity to distinguish observationally anthropogenic and biogenic CO2 sources and sinks. In addition, an evaluation of the sensitivity of the sectoral attribution to meteorological

  3. Affine and degenerate affine BMW algebras: The center

    CERN Document Server

    Daugherty, Zajj; Virk, Rahbar

    2011-01-01

    The degenerate affine and affine BMW algebras arise naturally in the context of Schur-Weyl duality for orthogonal and symplectic Lie algebras and quantum groups, respectively. Cyclotomic BMW algebras, affine Hecke algebras, cyclotomic Hecke algebras, and their degenerate versions are quotients. In this paper the theory is unified by treating the orthogonal and symplectic cases simultaneously; we make an exact parallel between the degenerate affine and affine cases via a new algebra which takes the role of the affine braid group for the degenerate setting. A main result of this paper is an identification of the centers of the affine and degenerate affine BMW algebras in terms of rings of symmetric functions which satisfy a "cancellation property" or "wheel condition" (in the degenerate case, a reformulation of a result of Nazarov). Miraculously, these same rings also arise in Schubert calculus, as the cohomology and K-theory of isotropic Grassmanians and symplectic loop Grassmanians. We also establish new inte...

  4. Hierarchical Affinity Propagation

    CERN Document Server

    Givoni, Inmar; Frey, Brendan J

    2012-01-01

    Affinity propagation is an exemplar-based clustering algorithm that finds a set of data-points that best exemplify the data, and associates each datapoint with one exemplar. We extend affinity propagation in a principled way to solve the hierarchical clustering problem, which arises in a variety of domains including biology, sensor networks and decision making in operational research. We derive an inference algorithm that operates by propagating information up and down the hierarchy, and is efficient despite the high-order potentials required for the graphical model formulation. We demonstrate that our method outperforms greedy techniques that cluster one layer at a time. We show that on an artificial dataset designed to mimic the HIV-strain mutation dynamics, our method outperforms related methods. For real HIV sequences, where the ground truth is not available, we show our method achieves better results, in terms of the underlying objective function, and show the results correspond meaningfully to geographi...

  5. Antibody affinity maturation

    DEFF Research Database (Denmark)

    Skjødt, Mette Louise

    linker for yeast surface display of scFv and scFab fragments, we compared a series of different Gly-Ser-based linkers in display and antigen binding proficiency. We show that these formats of the model antibody can accommodate linkers of different lengths and that introduction of alanine or glutamate......-2. Based on the presented data we suggest that affinity maturation of the model antibody proceeds through multiple incremental steps of subtle improvements. We moreover conclude that the best affinity improved candidates are likely to be obtained through optimization of both the antigen...... fragments by in vivo homologous recombination large combinatorial antibody libraries can easily be generated. We have optimized ordered assembly of three CDR fragments into a gapped vector and observed increased transformation efficiency in a yeast strain carrying a deletion of the SGS1 helicase...

  6. Gaussian Affine Feature Detector

    OpenAIRE

    Xu, Xiaopeng; Zhang, Xiaochun

    2011-01-01

    A new method is proposed to get image features' geometric information. Using Gaussian as an input signal, a theoretical optimal solution to calculate feature's affine shape is proposed. Based on analytic result of a feature model, the method is different from conventional iterative approaches. From the model, feature's parameters such as position, orientation, background luminance, contrast, area and aspect ratio can be extracted. Tested with synthesized and benchmark data, the method achieve...

  7. Affinity driven social networks

    Science.gov (United States)

    Ruyú, B.; Kuperman, M. N.

    2007-04-01

    In this work we present a model for evolving networks, where the driven force is related to the social affinity between individuals of a population. In the model, a set of individuals initially arranged on a regular ordered network and thus linked with their closest neighbors are allowed to rearrange their connections according to a dynamics closely related to that of the stable marriage problem. We show that the behavior of some topological properties of the resulting networks follows a non trivial pattern.

  8. Affine morphisms at zero level

    CERN Document Server

    Das, Paramita; Gupta, Ved Prakash

    2010-01-01

    Given a finite index subfactor, we show that the {\\em affine morphisms at zero level} in the affine category over the planar algebra associated to the subfactor is isomorphic to the fusion algebra of the subfactor as a *-algebra.

  9. On the Affine Isoperimetric Inequalities

    Indian Academy of Sciences (India)

    Wuyang Yu; Gangsong Leng

    2011-11-01

    We obtain an isoperimetric inequality which estimate the affine invariant -surface area measure on convex bodies. We also establish the reverse version of -Petty projection inequality and an affine isoperimetric inequality of $_{-p}K$.

  10. Adjoint affine fusion and tadpoles

    OpenAIRE

    Urichuk, Andrew; Walton, Mark A.

    2016-01-01

    We study affine fusion with the adjoint representation. For simple Lie algebras, elementary and universal formulas determine the decomposition of a tensor product of an integrable highest-weight representation with the adjoint representation. Using the (refined) affine depth rule, we prove that equally striking results apply to adjoint affine fusion. For diagonal fusion, a coefficient equals the number of nonzero Dynkin labels of the relevant affine highest weight, minus 1. A nice lattice-pol...

  11. Affine Patches on Positroid Varieties and Affine Pipe Dreams (Thesis)

    CERN Document Server

    Snider, Michelle

    2010-01-01

    The objects of interest in this thesis are positroid varieties in the Grassmannian, which are indexed by juggling patterns. In particular, we study affine patches on these positroid varieties. Our main result corresponds these affine patches to Kazhdan-Lusztig varieties in the affine Grassmannian. We develop a new term order and study how these spaces are related to subword complexes and Stanley-Reisner ideals. We define an extension of pipe dreams to the affine case and conclude by showing how our affine pipe dreams are generalizations of Cauchon and Le diagrams.

  12. Affine and quasi-affine frames for rational dilations

    DEFF Research Database (Denmark)

    Bownik, Marcin; Lemvig, Jakob

    2011-01-01

    , the corresponding family of quasi-affine systems are frames with uniform frame bounds. We also prove a similar equivalence result between pairs of dual affine frames and dual quasi-affine frames. Finally, we uncover some fundamental differences between the integer and rational settings by exhibiting an example......In this paper we extend the investigation of quasi-affine systems, which were originally introduced by Ron and Shen [J. Funct. Anal. 148 (1997), 408-447] for integer, expansive dilations, to the class of rational, expansive dilations. We show that an affine system is a frame if, and only if...

  13. Continuous Influx of Genetic Material from Host to Virus Populations.

    Science.gov (United States)

    Gilbert, Clément; Peccoud, Jean; Chateigner, Aurélien; Moumen, Bouziane; Cordaux, Richard; Herniou, Elisabeth A

    2016-02-01

    Many genes of large double-stranded DNA viruses have a cellular origin, suggesting that host-to-virus horizontal transfer (HT) of DNA is recurrent. Yet, the frequency of these transfers has never been assessed in viral populations. Here we used ultra-deep DNA sequencing of 21 baculovirus populations extracted from two moth species to show that a large diversity of moth DNA sequences (n = 86) can integrate into viral genomes during the course of a viral infection. The majority of the 86 different moth DNA sequences are transposable elements (TEs, n = 69) belonging to 10 superfamilies of DNA transposons and three superfamilies of retrotransposons. The remaining 17 sequences are moth sequences of unknown nature. In addition to bona fide DNA transposition, we uncover microhomology-mediated recombination as a mechanism explaining integration of moth sequences into viral genomes. Many sequences integrated multiple times at multiple positions along the viral genome. We detected a total of 27,504 insertions of moth sequences in the 21 viral populations and we calculate that on average, 4.8% of viruses harbor at least one moth sequence in these populations. Despite this substantial proportion, no insertion of moth DNA was maintained in any viral population after 10 successive infection cycles. Hence, there is a constant turnover of host DNA inserted into viral genomes each time the virus infects a moth. Finally, we found that at least 21 of the moth TEs integrated into viral genomes underwent repeated horizontal transfers between various insect species, including some lepidopterans susceptible to baculoviruses. Our results identify host DNA influx as a potent source of genetic diversity in viral populations. They also support a role for baculoviruses as vectors of DNA HT between insects, and call for an evaluation of possible gene or TE spread when using viruses as biopesticides or gene delivery vectors. PMID:26829124

  14. Continuous Influx of Genetic Material from Host to Virus Populations.

    Directory of Open Access Journals (Sweden)

    Clément Gilbert

    2016-02-01

    Full Text Available Many genes of large double-stranded DNA viruses have a cellular origin, suggesting that host-to-virus horizontal transfer (HT of DNA is recurrent. Yet, the frequency of these transfers has never been assessed in viral populations. Here we used ultra-deep DNA sequencing of 21 baculovirus populations extracted from two moth species to show that a large diversity of moth DNA sequences (n = 86 can integrate into viral genomes during the course of a viral infection. The majority of the 86 different moth DNA sequences are transposable elements (TEs, n = 69 belonging to 10 superfamilies of DNA transposons and three superfamilies of retrotransposons. The remaining 17 sequences are moth sequences of unknown nature. In addition to bona fide DNA transposition, we uncover microhomology-mediated recombination as a mechanism explaining integration of moth sequences into viral genomes. Many sequences integrated multiple times at multiple positions along the viral genome. We detected a total of 27,504 insertions of moth sequences in the 21 viral populations and we calculate that on average, 4.8% of viruses harbor at least one moth sequence in these populations. Despite this substantial proportion, no insertion of moth DNA was maintained in any viral population after 10 successive infection cycles. Hence, there is a constant turnover of host DNA inserted into viral genomes each time the virus infects a moth. Finally, we found that at least 21 of the moth TEs integrated into viral genomes underwent repeated horizontal transfers between various insect species, including some lepidopterans susceptible to baculoviruses. Our results identify host DNA influx as a potent source of genetic diversity in viral populations. They also support a role for baculoviruses as vectors of DNA HT between insects, and call for an evaluation of possible gene or TE spread when using viruses as biopesticides or gene delivery vectors.

  15. Affinity Purification of Insulin by Peptide-Ligand Affinity Chromatography

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The affinity heptapeptide (HWWWPAS) for insulin, selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column. The column was used for the affinity purification of insulin from protein mixture and commercial insulin preparation. It was observed that the minor impurity in the commercial insulin was removed by the affinity chromatography. Nearly 40 mg of insulin could be purified with the 1-mL affinity column. The results revealed the high specificity and capacity of the affinity column for insulin purification. Moreover, based on the analysis of the amino acids in the peptide sequence, shorter peptides were designed and synthesized for insulin chromatography. As a result, HWWPS was found to be a good alternative to HWWWPAS, while the other two peptides with three or four amino acids showed weak affinity for insulin. The results indicated that the peptide sequence of HWWWPAS was quite conservative for specific binding of insulin.

  16. The Utility of Affine Variables and Affine Coherent States

    CERN Document Server

    Klauder, John R

    2011-01-01

    Affine coherent states are generated by affine kinematical variables much like canonical coherent states are generated by canonical kinematical variables. Although all classical and quantum formalisms normally entail canonical variables, it is shown that affine variables can serve equally well for many classical and quantum studies. This general purpose analysis provides tools to discuss two major applications: (1) the completely successful quantization of a nonrenormalizable scalar quantum field theory by affine techniques, in complete contrast to canonical techniques which only offer triviality; and (2) a formulation of the kinematical portion of quantum gravity that favors affine kinematical variables over canonical kinematical variables, and which generates a framework in which a favorable analysis of the constrained dynamical issues can take place. All this is possible because of the close connection between the affine and the canonical stories, while the few distinctions can be used to advantage when ap...

  17. Jacobi Structures on Affine Bundles

    Institute of Scientific and Technical Information of China (English)

    J. GRABOWSKI; D. IGLESIAS; J. C. MARRERO; E. PADR(O)N; P. URBA(N)SKI

    2007-01-01

    We study affine Jacobi structures (brackets) on an affine bundle π: A→M, i.e. Jacobi brackets that close on affine functions. We prove that if the rank of A is non-zero, there is a one-to- one correspondence between affine Jacobi structures on A and Lie algebroid structures on the vector bundle A+=∪p∈M Aff(Ap, R) of affine functionals. In the case rank A = 0, it is shown that there is a one-to-one correspondence between affins Jacobi structures on A and local Lie algebras on A+. Some examples and applications, also for the linear case, are discussed. For a special type of affine Jacobi structures which are canonically exhibited (strongly-affine or affine-homogeneous Jacobi structures) over a real vector space of finite dimension, we describe the leaves of its characteristic foliation as the orbits of an affine representation. These afline Jacobi structures can be viewed as an analog of the Kostant-Arnold-LiouviUe linear Poisson structure on the dual space of a real finite-dimensional Lie algebra.

  18. Auxin influx carriers control vascular patterning and xylem differentiation in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Norma Fàbregas

    2015-04-01

    Full Text Available Auxin is an essential hormone for plant growth and development. Auxin influx carriers AUX1/LAX transport auxin into the cell, while auxin efflux carriers PIN pump it out of the cell. It is well established that efflux carriers play an important role in the shoot vascular patterning, yet the contribution of influx carriers to the shoot vasculature remains unknown. Here, we combined theoretical and experimental approaches to decipher the role of auxin influx carriers in the patterning and differentiation of vascular tissues in the Arabidopsis inflorescence stem. Our theoretical analysis predicts that influx carriers facilitate periodic patterning and modulate the periodicity of auxin maxima. In agreement, we observed fewer and more spaced vascular bundles in quadruple mutants plants of the auxin influx carriers aux1lax1lax2lax3. Furthermore, we show AUX1/LAX carriers promote xylem differentiation in both the shoot and the root tissues. Influx carriers increase cytoplasmic auxin signaling, and thereby differentiation. In addition to this cytoplasmic role of auxin, our computational simulations propose a role for extracellular auxin as an inhibitor of xylem differentiation. Altogether, our study shows that auxin influx carriers AUX1/LAX regulate vascular patterning and differentiation in plants.

  19. Adjoint affine fusion and tadpoles

    Science.gov (United States)

    Urichuk, Andrew; Walton, Mark A.

    2016-06-01

    We study affine fusion with the adjoint representation. For simple Lie algebras, elementary and universal formulas determine the decomposition of a tensor product of an integrable highest-weight representation with the adjoint representation. Using the (refined) affine depth rule, we prove that equally striking results apply to adjoint affine fusion. For diagonal fusion, a coefficient equals the number of nonzero Dynkin labels of the relevant affine highest weight, minus 1. A nice lattice-polytope interpretation follows and allows the straightforward calculation of the genus-1 1-point adjoint Verlinde dimension, the adjoint affine fusion tadpole. Explicit formulas, (piecewise) polynomial in the level, are written for the adjoint tadpoles of all classical Lie algebras. We show that off-diagonal adjoint affine fusion is obtained from the corresponding tensor product by simply dropping non-dominant representations.

  20. Adjoint affine fusion and tadpoles

    CERN Document Server

    Urichuk, Andrew

    2016-01-01

    We study affine fusion with the adjoint representation. For simple Lie algebras, elementary and universal formulas determine the decomposition of a tensor product of an integrable highest-weight representation with the adjoint representation. Using the (refined) affine depth rule, we prove that equally striking results apply to adjoint affine fusion. For diagonal fusion, a coefficient equals the number of nonzero Dynkin labels of the relevant affine highest weight, minus 1. A nice lattice-polytope interpretation follows, and allows the straightforward calculation of the genus-1 1-point adjoint Verlinde dimension, the adjoint affine fusion tadpole. Explicit formulas, (piecewise) polynomial in the level, are written for the adjoint tadpoles of all classical Lie algebras. We show that off-diagonal adjoint affine fusion is obtained from the corresponding tensor product by simply dropping non-dominant representations.

  1. Effects of several Chinese crude drugs on 45Ca transmembrane influx in vascular smooth muscles

    Institute of Scientific and Technical Information of China (English)

    ChenHeng-Liu; MoShang-Wu; 等

    1997-01-01

    The effects of several Chinese crude druge including Crocus sativus,Carthamus tinctorius and Ginkgo biloba on Ca2+ transmembrane influx in rat aorta rings were studied.Resting 45Ca uptake was not markedly altered by these drugs,whereas the 45 Ca influxes evoked by norepinephrine(1.2umol/L)and KCl(100mmol/L) in rat aorta rings were significantly inhibited by Crocus and Carthamus in a concentration-dependent manner,not by Ginkgo.The results indicate that extracellular Ca2+ tansmembrane influx through receptor-operated Ca2+ channels and potential-dependent Ca2+ channels can be blocked by crocus and Carthamus.

  2. Realization of Fractal Affine Transformation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper gives the definition of fractal affine transformation and presents a specific method for its realization and its cor responding mathematical equations which are essential in fractal image construction.

  3. Representations of affine Hecke algebras

    CERN Document Server

    Xi, Nanhua

    1994-01-01

    Kazhdan and Lusztig classified the simple modules of an affine Hecke algebra Hq (q E C*) provided that q is not a root of 1 (Invent. Math. 1987). Ginzburg had some very interesting work on affine Hecke algebras. Combining these results simple Hq-modules can be classified provided that the order of q is not too small. These Lecture Notes of N. Xi show that the classification of simple Hq-modules is essentially different from general cases when q is a root of 1 of certain orders. In addition the based rings of affine Weyl groups are shown to be of interest in understanding irreducible representations of affine Hecke algebras. Basic knowledge of abstract algebra is enough to read one third of the book. Some knowledge of K-theory, algebraic group, and Kazhdan-Lusztig cell of Cexeter group is useful for the rest

  4. Infinite transitivity on affine varieties

    OpenAIRE

    Arzhantsev, Ivan; Flenner, Hubert; Kaliman, Shulim; Kutzschebauch, Frank; ZAIDENBERG, MIKHAIL

    2012-01-01

    In this note we survey recent results on automorphisms of affine algebraic varieties, infinitely transitive group actions and flexibility. We present related constructions and examples, and discuss geometric applications and open problems.

  5. Cch1p mediates Ca2+ influx to protect Saccharomyces cerevisiae against eugenol toxicity.

    Science.gov (United States)

    Roberts, Stephen K; McAinsh, Martin; Widdicks, Lisa

    2012-01-01

    Eugenol has antifungal activity and is recognised as having therapeutic potential. However, little is known of the cellular basis of its antifungal activity and a better understanding of eugenol tolerance should lead to better exploitation of eugenol in antifungal therapies. The model yeast, Saccharomyces cerevisiae, expressing apoaequorin was used to show that eugenol induces cytosolic Ca(2+) elevations. We investigated the eugenol Ca(2+) signature in further detail and show that exponentially growing cells exhibit Ca(2+) elevation resulting exclusively from the influx of Ca(2+) across the plasma membrane whereas in stationary growth phase cells Ca(2+) influx from intracellular and extracellular sources contribute to the eugenol-induced Ca(2+) elevation. Ca(2+) channel deletion yeast mutants were used to identify the pathways mediating Ca(2+) influx; intracellular Ca(2+) release was mediated by the vacuolar Ca(2+) channel, Yvc1p, whereas the Ca(2+) influx across the plasma membrane could be resolved into Cch1p-dependent and Cch1p-independent pathways. We show that the growth of yeast devoid the plasma membrane Ca(2+) channel, Cch1p, was hypersensitive to eugenol and that this correlated with reduced Ca(2+) elevations. Taken together, these results indicate that a cch1p-mediated Ca(2+) influx is part of an intracellular signal which protects against eugenol toxicity. This study provides fresh insight into the mechanisms employed by fungi to tolerate eugenol toxicity which should lead to better exploitation of eugenol in antifungal therapies.

  6. Cch1p mediates Ca2+ influx to protect Saccharomyces cerevisiae against eugenol toxicity.

    Directory of Open Access Journals (Sweden)

    Stephen K Roberts

    Full Text Available Eugenol has antifungal activity and is recognised as having therapeutic potential. However, little is known of the cellular basis of its antifungal activity and a better understanding of eugenol tolerance should lead to better exploitation of eugenol in antifungal therapies. The model yeast, Saccharomyces cerevisiae, expressing apoaequorin was used to show that eugenol induces cytosolic Ca(2+ elevations. We investigated the eugenol Ca(2+ signature in further detail and show that exponentially growing cells exhibit Ca(2+ elevation resulting exclusively from the influx of Ca(2+ across the plasma membrane whereas in stationary growth phase cells Ca(2+ influx from intracellular and extracellular sources contribute to the eugenol-induced Ca(2+ elevation. Ca(2+ channel deletion yeast mutants were used to identify the pathways mediating Ca(2+ influx; intracellular Ca(2+ release was mediated by the vacuolar Ca(2+ channel, Yvc1p, whereas the Ca(2+ influx across the plasma membrane could be resolved into Cch1p-dependent and Cch1p-independent pathways. We show that the growth of yeast devoid the plasma membrane Ca(2+ channel, Cch1p, was hypersensitive to eugenol and that this correlated with reduced Ca(2+ elevations. Taken together, these results indicate that a cch1p-mediated Ca(2+ influx is part of an intracellular signal which protects against eugenol toxicity. This study provides fresh insight into the mechanisms employed by fungi to tolerate eugenol toxicity which should lead to better exploitation of eugenol in antifungal therapies.

  7. Abnormal mitochondrial function impairs calcium influx in diabetic mouse pancreatic beta cells

    Institute of Scientific and Technical Information of China (English)

    LI Fei; D. Marshall Porterfield; ZHENG Xi-yan; WANG Wen-jun; XU Yue; ZHANG Zong-ming

    2012-01-01

    Background Abnormal insulin secretion of pancreatic beta cells is now regarded as the more primary defect than the insulin function in the etiology of type 2 diabetes.Previous studies found impaired mitochondrial function and impaired Ca2+ influx in beta cells in diabetic patients and animal models,suggesting a role for these processes in proper insulin secretion.The aim of this study was to investigate the detailed relationship of mitochondrial function,Ca2+ influx,and defective insulin secretion.Methods We investigated mitochondrial function and morphology in pancreatic beta cell of diabetic KK-Ay mice and C57BL/6J mice.Two types of Ca2+ channel activities,L-type and store-operated Ca2+ (SOC),were evaluated using whole-cell patch-clamp recording.The glucose induced Ca2+ influx was measured by a non-invasive micro-test technique (NMT).Results Mitochondria in KK-Ay mice pancreatic beta cells were swollen with disordered cristae,and mitochondrial function decreased compared with C57BL/6J mice.Ca2+ channel activity was increased and glucose induced Ca2+ influx was impaired,but could be recovered by genipin.Conclusion Defective mitochondrial function in diabetic mice pancreatic beta cells is a key cause of abnormal insulin secretion by altering Ca2+ influx,but not via Ca2+ channel activity.

  8. Effect of Copper on l-Cysteine/l-Cystine Influx in Normal Human Erythrocytes and Erythrocytes of Wilson's Disease.

    Science.gov (United States)

    Mandal, Nabarun; Bhattacharjee, Debojyoti; Rout, Jayanta Kumar; Dasgupta, Anindya; Bhattacharya, Gorachand; Sarkar, Chandan; Gangopadhyaya, Prasanta Kumar

    2016-10-01

    Wilson's disease is a disease of abnormal copper metabolism in which free serum copper level is raised. The objective of the study was to determine, whether in Wilson disease, l-cysteine/l-cystine influx into RBC was decreased or not and the specific amino acid transporter affected by copper in normal human RBC. For l-cysteine/l-cystine influx, ten untreated cases, ten treated cases and ten age and sex matched healthy controls were recruited. To study the effect of copper on l-cysteine/l-cystine influx in RBC, 15 healthy subjects were selected. RBC GSH and l-cysteine/l-cystine influx were estimated by Beautler's and Yildiz's method respectively. In untreated cases, l-cysteine/l-cystine influx and erythrocyte GSH level were decreased showing that elevated level of free copper in serum or media decreased l-cysteine/l-cystine influx in human RBC. Copper treatment inhibited L amino acid transporter in normal RBC specifically.

  9. STIM1 and Orai1 mediate thrombin-induced Ca(2+) influx in rat cortical astrocytes.

    Science.gov (United States)

    Moreno, Claudia; Sampieri, Alicia; Vivas, Oscar; Peña-Segura, Claudia; Vaca, Luis

    2012-12-01

    In astrocytes, thrombin leads to cytoplasmic Ca(2+) elevations modulating a variety of cytoprotective and cytotoxic responses. Astrocytes respond to thrombin stimulation with a biphasic Ca(2+) increase generated by an interplay between ER-Ca(2+) release and store-operated Ca(2+) entry (SOCE). In many cell types, STIM1 and Orai1 have been demonstrated to be central components of SOCE. STIM1 senses the ER-Ca(2+) depletion and binds Orai1 to activate Ca(2+) influx. Here we used immunocytochemistry, overexpression and siRNA assays to investigate the role of STIM1 and Orai1 in the thrombin-induced Ca(2+) response in primary cultures of rat cortical astrocytes. We found that STIM1 and Orai1 are endogenously expressed in cortical astrocytes and distribute accordingly with other mammalian cells. Importantly, native and overexpressed STIM1 reorganized in puncta under thrombin stimulation and this reorganization was reversible. In addition, the overexpression of STIM1 and Orai1 increased by twofold the Ca(2+) influx evoked by thrombin, while knockdown of endogenous STIM1 and Orai1 significantly decreased this Ca(2+) influx. These results indicate that STIM1 and Orai1 underlie an important fraction of the Ca(2+) response that astrocytes exhibit in the presence of thrombin. Thrombin stimulation in astrocytes leads to ER-Ca(2+) release which causes STIM1 reorganization allowing the activation of Orai1 and the subsequent Ca(2+) influx.

  10. Mass Influx of Cosmic Dust Estimated From Vertical Transport of Meteoric Metals

    Science.gov (United States)

    Liu, Alan Z.; Guo, Yafang; Gardner, Chester S.

    2016-04-01

    The mesospheric metal layers are formed by the vaporization of high-speed cosmic dust particles in the lower thermosphere and upper mesosphere. The vaporized atoms and ions are transported downward by waves and turbulence to chemical sinks below 85 km, where they form stable compounds. These compounds condense onto meteoric smoke particles and are then transported to the winter pole where they eventually settle onto the surface. The downward fluxes of the metal atoms are directly related to their meteoric influxes and chemical loss rates. In this paper we use Doppler lidar measurements of Na and Fe fluxes made by the University of Illinois and University of Colorado groups, and a chemical ablation model (CABMOD) developed at the University of Leeds, to constrain the velocity/mass distribution of the meteoroids entering the atmosphere and to derive an improved estimate for the global influx of cosmic dust. We find that the particles responsible for injecting a large fraction of the ablated material into the Earth's upper atmosphere, enter at relatively slow speeds and originate primarily from the Jupiter Family of Comets. The global mean Na influx is 21,500±1,100 atoms/cm2/s, which equals 372±18 kg/d for the global input of Na vapor and 186±24 t/d for the global influx of cosmic dust. The global mean Fe influx is 131,000±36,000 atoms/cm2/s, which equals 5.5±1.5 t/d for the global input of Na vapor.

  11. Effects of AMPK on high glucose stimulated apoptosis of endothelial cells via regulation of calcium influx

    Directory of Open Access Journals (Sweden)

    Ting LU

    2015-11-01

    Full Text Available Objective To investigate the inhibitory effect of adenosine monophosphate (AMP-dependent protein kinase (AMPK on high glucose-stimulated endothelial cell apoptosis and its mechanism. Methods MS-1 endothelial cells were cultured in vitro, and they were treated with AMPK agonist, AMPK inhibitor, 2-APB (a blocker of store operated Ca2+ channel (SOCC and (or high glucose, and a control group without any intervention were set up. TUNEL assay was performed to determine apoptotic cells. Laser scanning confocal microscopy was used to assess the Ca2+ influx into cells, and Western-blotting was performed to determine the expressions of Stim1 and Orai1 of the store operated Ca2+ channel (SOCC proteins. Results Apoptosis of endothelial cells was induced significantly, and the expressions of Stim1 and Orai1 were upregulated in high glucose group compared with that in control group (P<0.05. The rate of apoptosis of high glucose-induced endothelial cell was found to be increased in AMPK inhibitor group and decreased in AMPK agonist group, and the expressions of Stim1 and Orai1 were found to be down-regulated in AMPK agonist group as compared with that in high glucose group (P<0.05. Compared with the control group, high glucose stimulation significantly induced the Ca2+ influx to endothelial cells; compared with high glucose group, 2-APB significantly inhibited high glucose-induced Ca2+ influx to endothelial cells, and blocked the inducing effect of high-glucose on endothelial cell apoptosis. Compared with high glucose group, AMPK agonist significantly inhibited high glucose-induced cell Ca2+ influx. Conclusion By reducing the expressions of Stim1 and Orai1, AMPK may inhibit SOCC-mediated Ca2+ influx, and block the high glucose-stimulated endothelial cell apoptosis, thus play an important protective role in sustaining endothelial cell function. DOI: 10.11855/j.issn.0577-7402.2015.10.01

  12. EGF stimulates Mg{sup 2+} influx in mammary epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Trapani, Valentina; Arduini, Daniela; Luongo, Francesca; Wolf, Federica I., E-mail: federica.wolf@rm.unicatt.it

    2014-11-28

    Highlights: • EGF stimulation potentiates Mg{sup 2+} influx into epithelial cells. • EGF-induced Mg{sup 2+} influx does not depend on the concomitantly induced Ca{sup 2+} signal. • EGF-induced Ca{sup 2+} signal is dependent on the presence of extracellular Mg{sup 2+}. • New players in EGF-mediated signaling might be exploited as therapeutic targets. - Abstract: Magnesium is well established as a fundamental factor that regulates cell proliferation. However, the molecular mechanisms linking mitogenic signals, extracellular magnesium availability and intracellular effectors are still largely unknown. In the present study we sought to determine whether EGF regulates magnesium homeostasis in normal HC11 mammary epithelial cells. To this end, we measured Mg{sup 2+} and Ca{sup 2+} fluxes by confocal imaging in live cells loaded with specific fluorescent ion indicators (Mag-Fluo-4 and Fluo-4, respectively). EGF stimulation induces a rapid and sustained increase in intracellular Mg{sup 2+}, concomitantly with a rise in intracellular calcium. The increase in intracellular Mg{sup 2+} derives from an influx from the extracellular compartment, and does not depend on Ca{sup 2+}. On the contrary, the increase in intracellular Ca{sup 2+} derives from intracellular stores, and is impaired in the absence of extracellular magnesium. Inhibition of the EGF receptor tyrosine kinase by Tyrphostin AG1478 markedly inhibits EGF-induced Mg{sup 2+} and Ca{sup 2+} signals. These findings demonstrate that not only does Mg{sup 2+} influx represent an important step in the physiological response of epithelial cells to EGF, but unexpectedly the EGF-induced Mg{sup 2+} influx is essential for the Ca{sup 2+} signal to occur.

  13. Affine density in wavelet analysis

    CERN Document Server

    Kutyniok, Gitta

    2007-01-01

    In wavelet analysis, irregular wavelet frames have recently come to the forefront of current research due to questions concerning the robustness and stability of wavelet algorithms. A major difficulty in the study of these systems is the highly sensitive interplay between geometric properties of a sequence of time-scale indices and frame properties of the associated wavelet systems. This volume provides the first thorough and comprehensive treatment of irregular wavelet frames by introducing and employing a new notion of affine density as a highly effective tool for examining the geometry of sequences of time-scale indices. Many of the results are new and published for the first time. Topics include: qualitative and quantitative density conditions for existence of irregular wavelet frames, non-existence of irregular co-affine frames, the Nyquist phenomenon for wavelet systems, and approximation properties of irregular wavelet frames.

  14. Inhomogeneous self-affine carpets

    OpenAIRE

    Fraser, Jonathan M.

    2013-01-01

    We investigate the dimension theory of inhomogeneous self-affine carpets. Through the work of Olsen, Snigireva and Fraser, the dimension theory of inhomogeneous self-similar sets is now relatively well-understood, however, almost no progress has been made concerning more general non-conformal inhomogeneous attractors. If a dimension is countably stable, then the results are immediate and so we focus on the upper and lower box dimensions and compute these explicitly for large classes of inhomo...

  15. Protein isolation using affinity chromatography

    OpenAIRE

    Besselink, T.

    2012-01-01

    Many product or even waste streams in the food industry contain components that may have potential for e.g. functional foods. These streams are typically large in volume and the components of interest are only present at low concentrations. A robust and highly selective separation process should be developed for efficient isolation of the components. Affinity chromatography is such a selective method. Ligands immobilized to a stationary phase (e.g., a resin or membrane) are used to bind the c...

  16. Lectin affinity chromatography of glycolipids

    Energy Technology Data Exchange (ETDEWEB)

    Torres, B.V.; Smith, D.F.

    1987-05-01

    Since glycolipids (GLs) are either insoluble or form mixed micelles in water, lectin affinity chromatography in aqueous systems has not been applied to their separation. They have overcome this problem by using tetrahydrofuran (THF) in the mobile phase during chromatography. Affinity columns prepared with the GalNAc-specific Helix pomatia agglutinin (HPA) and equilibrated in THF specifically bind the (/sup 3/H)oligosaccharide derived from Forssman GL indicating that the immobilized HPA retained its carbohydrate-binding specificity in this solvent. Intact Forssman GL was bound by the HPA-column equilibrated in THF and was specifically eluted with 0.1 mg/ml GalNAc in THF. Purification of the Forssman GL was achieved when a crude lipid extract of sheep erythrocyte membranes was applied to the HPA-column in THF. Non-specifically bound GLs were eluted from the column using a step gradient of aqueous buffer in THF, while the addition of GalNAc was required to elute the specifically bound GLs. Using this procedure the A-active GLs were purified from a crude lipid extract of type A human erythrocytes in a single chromatographic step. The use of solvents that maintain carbohydrate-binding specificity and lipid solubility will permit the application of affinity chromatography on immobilized carbohydrate-binding proteins to intact GLs.

  17. Involvement of phospholipase D in store-operated calcium influx in vascular smooth muscle cells.

    Science.gov (United States)

    Walter, M; Tepel, M; Nofer, J R; Neusser, M; Assmann, G; Zidek, W

    2000-08-11

    In non-excitable cells, sustained intracellular Ca2+ increase critically depends on influx of extracellular Ca2+. Such Ca2+ influx is thought to occur by a 'store-operated' mechanism, i.e. the signal for Ca2+ entry is believed to result from the initial release of Ca2+ from inositol 1,4,5-trisphosphate-sensitive intracellular stores. Here we show that the depletion of cellular Ca2+ stores by thapsigargin or bradykinin is functionally linked to a phosphoinositide-specific phospholipase D (PLD) activity in cultured vascular smooth muscle cells (VSMC), and that phosphatidic acid formed via PLD enhances sustained calcium entry in this cell type. These results suggest a regulatory role for PLD in store-operated Ca2+ entry in VSMC.

  18. Neuronal processing of noxious thermal stimuli mediated by dendritic Ca(2+) influx in Drosophila somatosensory neurons.

    Science.gov (United States)

    Terada, Shin-Ichiro; Matsubara, Daisuke; Onodera, Koun; Matsuzaki, Masanori; Uemura, Tadashi; Usui, Tadao

    2016-02-15

    Adequate responses to noxious stimuli causing tissue damages are essential for organismal survival. Class IV neurons in Drosophila larvae are polymodal nociceptors responsible for thermal, mechanical, and light sensation. Importantly, activation of Class IV provoked distinct avoidance behaviors, depending on the inputs. We found that noxious thermal stimuli, but not blue light stimulation, caused a unique pattern of Class IV, which were composed of pauses after high-frequency spike trains and a large Ca(2+) rise in the dendrite (the Ca(2+) transient). Both these responses depended on two TRPA channels and the L-type voltage-gated calcium channel (L-VGCC), showing that the thermosensation provokes Ca(2+) influx. The precipitous fluctuation of firing rate in Class IV neurons enhanced the robust heat avoidance. We hypothesize that the Ca(2+) influx can be a key signal encoding a specific modality.

  19. Individual aggregates of amyloid beta induce temporary calcium influx through the cell membrane of neuronal cells

    Science.gov (United States)

    Drews, Anna; Flint, Jennie; Shivji, Nadia; Jönsson, Peter; Wirthensohn, David; De Genst, Erwin; Vincke, Cécile; Muyldermans, Serge; Dobson, Chris; Klenerman, David

    2016-01-01

    Local delivery of amyloid beta oligomers from the tip of a nanopipette, controlled over the cell surface, has been used to deliver physiological picomolar oligomer concentrations to primary astrocytes or neurons. Calcium influx was observed when as few as 2000 oligomers were delivered to the cell surface. When the dosing of oligomers was stopped the intracellular calcium returned to basal levels or below. Calcium influx was prevented by the presence in the pipette of the extracellular chaperone clusterin, which is known to selectively bind oligomers, and by the presence a specific nanobody to amyloid beta. These data are consistent with individual oligomers larger than trimers inducing calcium entry as they cross the cell membrane, a result supported by imaging experiments in bilayers, and suggest that the initial molecular event that leads to neuronal damage does not involve any cellular receptors, in contrast to work performed at much higher oligomer concentrations. PMID:27553885

  20. Influx of CO2 from Soil Incubated Organic Residues at Constant Temperature

    Directory of Open Access Journals (Sweden)

    Shoukat Ali Abro

    2016-06-01

    Full Text Available Temperature induced CO2 from genotypic residue substances is still less understood. Two types of organic residues (wheat- maize were incubated at a constant temperature (25°C to determine the rate and cumulative influx of CO2 in laboratory experiment for 40 days. Further, the effect of surface and incorporated crop residues with and without phosphorus addition was also studied. Results revealed that mixing of crop residues increased CO2-C evolution significantly & emission rare was 37% higher than that of control. At constant temperature, soil mixed residues, had higher emission rates CO2-C than the residues superimposed. There was linear correlation of CO2-C influxed for phosphorus levels and residue application ways with entire incubation at constant temperature. The mixing of organic residues to soil enhanced SOC levels and biomass of microbially bound N; however to little degree ammonium (NH4-N and nitrate NO3-N nitrogen were decreased.

  1. Intracellular pH changes induced by calcium influx during electrical activity in molluscan neurons

    OpenAIRE

    1980-01-01

    Simultaneous measurements of electrical activity and light absorbance have been made on nerve cell bodies from Archidoris monteryensis injected with indicator dyes. pH indicators, phenol red and bromocresol purple, and arsenazo III, which under normal conditions is primarily a calcium indicator have been employed. Voltage clamp pulses which induced calcium influx caused an absorbance decrease of the pH dyes indicating an internal acidification. The onset of the pH drop lagged the onset of Ca2...

  2. Auxin influx inhibitors 1-NOA, 2-NOA, and CHPAA interfere with membrane dynamics in tobacco cells

    OpenAIRE

    Laňková, M. (Martina); Smith, R. S.; Pešek, B. (Bedřich); Kubeš, M. (Martin); Zažímalová, E. (Eva); Petrášek, J. (Jan); Hoyerová, K.

    2010-01-01

    The phytohormone auxin is transported through the plant body either via vascular pathways or from cell to cell by specialized polar transport machinery. This machinery consists of a balanced system of passive diffusion combined with the activities of auxin influx and efflux carriers. Synthetic auxins that differ in the mechanisms of their transport across the plasma membrane together with polar auxin transport inhibitors have been used in many studies on particular auxin carriers and their ro...

  3. Basophil response to antigen and anti-IgE 3. Ca(2+) influx and histamine release

    OpenAIRE

    Tanizaki,Yoshiro; Kitani,Hikaru; Okazaki, Morihiro; Mifune, Takashi; Mitsunobu, Fumihiro; Kimura,Ikuro

    1992-01-01

    The release mechanism of chemical mediators from basophils and mast cells was discussed when these cells were stimulated by different antigens and anti-IgE. 1. Ca(2+) influx into mast cells increased after stimulation by antigen. The increased Ca(2+) uptake by mast cells was inhibited by antiallergic agents, disodium cromoglycate (DSCG) and tranilast, and calcium antagonists, nifedipine and nicardipine. 2. The dose-response curve of histamine release by antigen was different from that by anti...

  4. Calcium influx is sufficient to induce muscular dystrophy through a TRPC-dependent mechanism

    OpenAIRE

    Millay, Douglas P.; Goonasekera, Sanjeewa A.; Sargent, Michelle A.; Maillet, Marjorie; Aronow, Bruce J; Molkentin, Jeffery D.

    2009-01-01

    Muscular dystrophy is a general term encompassing muscle disorders that cause weakness and wasting, typically leading to premature death. Membrane instability, as a result of a genetic disruption within the dystrophin-glycoprotein complex (DGC), is thought to induce myofiber degeneration, although the downstream mechanism whereby membrane fragility leads to disease remains controversial. One potential mechanism that has yet to be definitively proven in vivo is that unregulated calcium influx ...

  5. Characterization of Na+ influx mediated by ATP(4-)-activated P2 purinoceptors in PC12 cells.

    OpenAIRE

    Choi, S. Y.; Kim, K. T.

    1996-01-01

    1. Micromolar levels of extracellular ATP increased cytosolic Na+ concentration ([Na+]i) as well as cytosolic Ca2+ concentration ([Ca2+]i) in PC12 cells. 2. Pretreatment of cells with tetrodotoxin, benzamil or thapsigargin did not alter the ATP-induced Na+ influx. 3. Increased extracellular Mg2+ concentration decreased the ATP effect. Furthermore, when the extracellular ATP pool was treated to contain corresponding calculated concentrations of ATP4-, the increase in [Na+]i stayed linked to th...

  6. Absence of correlation between ACh-induced Ca influx and phosphatidic acid labeling in rat uterus.

    Science.gov (United States)

    Ichida, S; Moriyama, M; Hirooka, Y; Okazaki, Y; Yoshioka, K

    1984-11-27

    Rat uterine smooth muscle was preincubated in Ca-depleted modified Locke-Ringer solution to investigate the correlation between the 32Pi incorporation into phosphatidic acid induced by acetylcholine and the contractile response to acetylcholine induced by the addition of CaCl2 (Ca influx). The results showed that in rat uterine smooth muscle under these conditions phosphatidic acid does not act as a Ca ionophore or as a trigger for opening the Ca channel.

  7. Alternative affinity tools: more attractive than antibodies?

    NARCIS (Netherlands)

    Ruigrok, V.J.B.; Levisson, M.; Eppink, M.H.M.; Smidt, H.; Oost, van der J.

    2011-01-01

    Antibodies are the most successful affinity tools used today, in both fundamental and applied research (diagnostics, purification and therapeutics). Nonetheless, antibodies do have their limitations, including high production costs and low stability. Alternative affinity tools based on nucleic acids

  8. Spectral affinity in protein networks

    Directory of Open Access Journals (Sweden)

    Teng Shang-Hua

    2009-11-01

    Full Text Available Abstract Background Protein-protein interaction (PPI networks enable us to better understand the functional organization of the proteome. We can learn a lot about a particular protein by querying its neighborhood in a PPI network to find proteins with similar function. A spectral approach that considers random walks between nodes of interest is particularly useful in evaluating closeness in PPI networks. Spectral measures of closeness are more robust to noise in the data and are more precise than simpler methods based on edge density and shortest path length. Results We develop a novel affinity measure for pairs of proteins in PPI networks, which uses personalized PageRank, a random walk based method used in context-sensitive search on the Web. Our measure of closeness, which we call PageRank Affinity, is proportional to the number of times the smaller-degree protein is visited in a random walk that restarts at the larger-degree protein. PageRank considers paths of all lengths in a network, therefore PageRank Affinity is a precise measure that is robust to noise in the data. PageRank Affinity is also provably related to cluster co-membership, making it a meaningful measure. In our experiments on protein networks we find that our measure is better at predicting co-complex membership and finding functionally related proteins than other commonly used measures of closeness. Moreover, our experiments indicate that PageRank Affinity is very resilient to noise in the network. In addition, based on our method we build a tool that quickly finds nodes closest to a queried protein in any protein network, and easily scales to much larger biological networks. Conclusion We define a meaningful way to assess the closeness of two proteins in a PPI network, and show that our closeness measure is more biologically significant than other commonly used methods. We also develop a tool, accessible at http://xialab.bu.edu/resources/pnns, that allows the user to

  9. Control of Ca2+ Influx and Calmodulin Activation by SK-Channels in Dendritic Spines.

    Directory of Open Access Journals (Sweden)

    Thom Griffith

    2016-05-01

    Full Text Available The key trigger for Hebbian synaptic plasticity is influx of Ca2+ into postsynaptic dendritic spines. The magnitude of [Ca2+] increase caused by NMDA-receptor (NMDAR and voltage-gated Ca2+ -channel (VGCC activation is thought to determine both the amplitude and direction of synaptic plasticity by differential activation of Ca2+ -sensitive enzymes such as calmodulin. Ca2+ influx is negatively regulated by Ca2+ -activated K+ channels (SK-channels which are in turn inhibited by neuromodulators such as acetylcholine. However, the precise mechanisms by which SK-channels control the induction of synaptic plasticity remain unclear. Using a 3-dimensional model of Ca2+ and calmodulin dynamics within an idealised, but biophysically-plausible, dendritic spine, we show that SK-channels regulate calmodulin activation specifically during neuron-firing patterns associated with induction of spike timing-dependent plasticity. SK-channel activation and the subsequent reduction in Ca2+ influx through NMDARs and L-type VGCCs results in an order of magnitude decrease in calmodulin (CaM activation, providing a mechanism for the effective gating of synaptic plasticity induction. This provides a common mechanism for the regulation of synaptic plasticity by neuromodulators.

  10. Heat and hyposmotic stimulation increase in [Ca2+]i by Ca2+ influx in rat synoviocytes

    Institute of Scientific and Technical Information of China (English)

    SUN WenWu; HU Fen; YANG WenXiu

    2008-01-01

    Rheumatoid arthritis (RA), which is marked by inflammatory synovitis, is a common, chronic autoimmune-disease, whose pathogenesis is complex and still unclear. In order to explore the effects of heat and hyposmotic stimuli on synoviocytes in rheumatoid arthritis, the changes of [Ca2+]i induced by heat, hyposmotic and 4α-PDD stimuli were observed in synoviocytes. [Ca2+]i elevation induced by heat ≥ 28℃, hyposmotic and 4α-PDD stimuli is found to be positively relative to increasing temperature, decreasing osmolality and rising concentration of 4α-PDD. Results show that there is reciprocity among these stimuli and desensitization, and that [Ca2+]i elevation depends on Ca2+ influx, but not necessarily links to Ca2+ release from intracellular stores and voltage-dependent Ca2+ channel in synoviocytes. The above characteristics of Ca2+ influx are similar to those of TRPV4. A probable mechanism has been suggested that heat and hyposmotic stimulation might increase the level of [Ca2+]i by activating the TRPV4-like channel and Ca2+ influx in the synoviocytes.

  11. Proton cellular influx as a probable mechanism of variation potential influence on photosynthesis in pea.

    Science.gov (United States)

    Sukhov, Vladimir; Sherstneva, Oksana; Surova, Lyubov; Katicheva, Lyubov; Vodeneev, Vladimir

    2014-11-01

    Electrical signals (action potential and variation potential, VP) caused by environmental stimuli are known to induce various physiological responses in plants, including changes in photosynthesis; however, their functional mechanisms remain unclear. In this study, the influence of VP on photosynthesis in pea (Pisum sativum L.) was investigated and the proton participation in this process analysed. VP, induced by local heating, inactivated photosynthesis and activated respiration, with the initiation of the photosynthetic response connected with inactivation of the photosynthetic dark stage; however, direct VP influence on the light stage was also probable. VP generation was accompanied with pH increases in apoplasts (0.17-0.30 pH unit) and decreases in cytoplasm (0.18-0.60 pH unit), which probably reflected H(+) -ATPase inactivation and H(+) influx during this electrical event. Imitation of H(+) influx using the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) induced a photosynthetic response that was similar with a VP-induced response. Experiments on chloroplast suspensions showed that decreased external pH also induced an analogous response and that its magnitude depended on the magnitude of pH change. Thus, the present results showed that proton cellular influx was the probable mechanism of VP's influence on photosynthesis in pea. Potential means of action for this influence are discussed.

  12. Manifolds with integrable affine shape operator

    Directory of Open Access Journals (Sweden)

    Daniel A. Joaquín

    2005-05-01

    Full Text Available This work establishes the conditions for the existence of vector fields with the property that theirs covariant derivative, with respect to the affine normal connection, be the affine shape operatorS in hypersurfaces. Some results are obtained from this property and, in particular, for some kind of affine decomposable hypersurfaces we explicitely get the actual vector fields.

  13. Rational self-affine tiles

    CERN Document Server

    Steiner, Wolfgang

    2012-01-01

    An integral self-affine tile is the solution of a set equation $\\mathbf{A} \\mathcal{T} = \\bigcup_{d \\in \\mathcal{D}} (\\mathcal{T} + d)$, where $\\mathbf{A}$ is an $n \\times n$ integer matrix and $\\mathcal{D}$ is a finite subset of $\\mathbb{Z}^n$. In the recent decades, these objects and the induced tilings have been studied systematically. We extend this theory to matrices $\\mathbf{A} \\in \\mathbb{Q}^{n \\times n}$. We define rational self-affine tiles as compact subsets of the open subring $\\mathbb{R}^n\\times \\prod_\\mathfrak{p} K_\\mathfrak{p}$ of the ad\\'ele ring $\\mathbb{A}_K$, where the factors of the (finite) product are certain $\\mathfrak{p}$-adic completions of a number field $K$ that is defined in terms of the characteristic polynomial of $\\mathbf{A}$. Employing methods from classical algebraic number theory, Fourier analysis in number fields, and results on zero sets of transfer operators, we establish a general tiling theorem for these tiles. We also associate a second kind of tiles with a rational matr...

  14. Graded electron affinity electron source

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J.L.; Gray, H.F.; Jensen, K.L.; Jung, T.M. [Naval Research Laboratory, Washington, DC 20375 (United States)

    1996-05-01

    We describe a new electron source using electric field and low electron affinity semiconductor materials to bring charge to potential energy levels near the vacuum level while still in the solid. The basic idea involves moving some of the potential barrier from the surface to the bulk, and distributing the barrier over a thin layer below the surface. In so doing, the emission physics is changed fundamentally from a quantum mechanical tunneling process largely controlled by surface properties to a classical transport process largely controlled by the band structure of a wide bandgap semiconductor. The composition of the thin layer below the surface would be graded such that the conduction band minimum changes from an energy close to the substrate Fermi level to an energy significantly closer to the vacuum level. Electrons from the substrate would be drawn into the graded composition layer with an electric field produced by a pointed emitter structure and extraction gate similar to that used in field emitter arrays. Relative to a conventional field emitter array, the new source is expected to require lower extraction fields and exhibit improved emission uniformity, stability, and noise. The {ital I}{endash}{ital V} characteristics are not Fowler{endash}Nordheim and may include a saturation effect at high current densities that could be engineered to improve reliability and uniformity. The group III nitrides can be grown with a continuous range of composition that provides the range of electron affinity needed to produce the proposed electronic structure. {copyright} {ital 1996 American Vacuum Society}

  15. The affine quantum gravity programme

    International Nuclear Information System (INIS)

    The central principle of affine quantum gravity is securing and maintaining the strict positivity of the matrix { g-hat ab(x)} composed of the spatial components of the local metric operator. On spectral grounds, canonical commutation relations are incompatible with this principle, and they must be replaced by noncanonical, affine commutation relations. Due to the partial second-class nature of the quantum gravitational constraints, it is advantageous to use the recently developed projection operator method, which treats all quantum constraints on an equal footing. Using this method, enforcement of regularized versions of the gravitational operator constraints is formulated quite naturally by means of a novel and relatively well-defined functional integral involving only the same set of variables that appears in the usual classical formulation. It is anticipated that skills and insight to study this formulation can be developed by studying special, reduced-variable models that still retain some basic characteristics of gravity, specifically a partial second-class constraint operator structure. Although perturbatively nonrenormalizable, gravity may possibly be understood nonperturbatively from a hard-core perspective that has proved valuable for specialized models. Finally, developing a procedure to pass to the genuine physical Hilbert space involves several interconnected steps that require careful coordination

  16. A morphologic study of the influx of neutrophils into dog lung alveoli after lavage with sterile saline.

    OpenAIRE

    Damiano, V. V.; Cohen, A; Tsang, A. L.; Batra, G.; Petersen, R

    1980-01-01

    The appearance of neutrophils in the alveoli of the lung is a common result of pulmonary infection, although the route of neutrophil migration across the alveolar wall has not been demonstrated in normal animals. Recently, however, several methods of stimulating the influx of neutrophils into alveoli have been developed. In the present study, the lung wash model was used to attract large numbers of neutrophils into the airways in order to identify the site of influx of alveolar neutrophils. T...

  17. Hair cells use active zones with different voltage dependence of Ca2+ influx to decompose sounds into complementary neural codes.

    Science.gov (United States)

    Ohn, Tzu-Lun; Rutherford, Mark A; Jing, Zhizi; Jung, Sangyong; Duque-Afonso, Carlos J; Hoch, Gerhard; Picher, Maria Magdalena; Scharinger, Anja; Strenzke, Nicola; Moser, Tobias

    2016-08-01

    For sounds of a given frequency, spiral ganglion neurons (SGNs) with different thresholds and dynamic ranges collectively encode the wide range of audible sound pressures. Heterogeneity of synapses between inner hair cells (IHCs) and SGNs is an attractive candidate mechanism for generating complementary neural codes covering the entire dynamic range. Here, we quantified active zone (AZ) properties as a function of AZ position within mouse IHCs by combining patch clamp and imaging of presynaptic Ca(2+) influx and by immunohistochemistry. We report substantial AZ heterogeneity whereby the voltage of half-maximal activation of Ca(2+) influx ranged over ∼20 mV. Ca(2+) influx at AZs facing away from the ganglion activated at weaker depolarizations. Estimates of AZ size and Ca(2+) channel number were correlated and larger when AZs faced the ganglion. Disruption of the deafness gene GIPC3 in mice shifted the activation of presynaptic Ca(2+) influx to more hyperpolarized potentials and increased the spontaneous SGN discharge. Moreover, Gipc3 disruption enhanced Ca(2+) influx and exocytosis in IHCs, reversed the spatial gradient of maximal Ca(2+) influx in IHCs, and increased the maximal firing rate of SGNs at sound onset. We propose that IHCs diversify Ca(2+) channel properties among AZs and thereby contribute to decomposing auditory information into complementary representations in SGNs. PMID:27462107

  18. Hypericum caprifoliatum and Hypericum connatum affect human trophoblast-like cells differentiation and Ca2+influx

    Institute of Scientific and Technical Information of China (English)

    Aline O da Conceio; Gilsane Lino von Poser; Benoit Barbeau; Julie Lafond

    2014-01-01

    Objective:To study the effect of crude methanol and n-hexane extracts of Hypericum connatum (H. connatum) and Hypericum caprifoliatum on trophoblast-like cells. Methods: BeWo and JEG-3 trophoblast-like cells were submitted to different extract concentrations (1, 5, 10 and 15 µg/mL) and evaluated in relation to cell viability and in vitro trophoblast differentiation and function. Cell viability was evaluated using WST-1 reagent. Differentiation was measured by luciferase production, hCG production/release, and mitogen-activated protein kinase signaling pathway activation. The function of the trophoblast-like cells was measured by 45Ca2+influx evaluation. Results:The results showed a decrease in cell viability/proliferation. Both plants and different extracts induced a significant decrease in hCG production/release and luciferase production. H. connatum did not cause mitogen-activated protein kinase signaling pathway disturbance;however, Hypericum caprifoliatum n-hexane extract at 15 µg/mL inhibited extracellular signal-regulated kinase 1/2 activation. The significant increase in Ca2+influx by JEG-3 cells was seen after short and long incubation times with H. connatum methanolic extract at 15 µg/mL. Conclusions: The results indicated that these two Hypericum species extracts can interfere on trophoblast differentiation and Ca2+influx, according to their molecular diversity. Although in vivo experiments are necessary to establish their action on placental formation and function, this study suggests that attention must be paid to the potential toxic effect of these plants.

  19. Ca{sup 2+} influx and ATP release mediated by mechanical stretch in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Naohiko [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Ito, Satoru, E-mail: itori@med.nagoya-u.ac.jp [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Furuya, Kishio [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Takahara, Norihiro [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Naruse, Keiji [Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Okayama 700-8558 (Japan); Aso, Hiromichi; Kondo, Masashi [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Sokabe, Masahiro [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Hasegawa, Yoshinori [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan)

    2014-10-10

    Highlights: • Uniaxial stretching activates Ca{sup 2+} signaling in human lung fibroblasts. • Stretch-induced intracellular Ca{sup 2+} elevation is mainly via Ca{sup 2+} influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca{sup 2+} influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca{sup 2+}]{sub i} transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca{sup 2+}]{sub i}. The stretch-induced [Ca{sup 2+}]{sub i} elevation was attenuated in Ca{sup 2+}-free solution. In contrast, the increase of [Ca{sup 2+}]{sub i} by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd{sup 3+}, ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca{sup 2+}]{sub i} elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca{sup 2+} influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

  20. Methods for Improving Aptamer Binding Affinity

    OpenAIRE

    Hijiri Hasegawa; Nasa Savory; Koichi Abe; Kazunori Ikebukuro

    2016-01-01

    Aptamers are single stranded oligonucleotides that bind a wide range of biological targets. Although aptamers can be isolated from pools of random sequence oligonucleotides using affinity-based selection, aptamers with high affinities are not always obtained. Therefore, further refinement of aptamers is required to achieve desired binding affinities. The optimization of primary sequences and stabilization of aptamer conformations are the main approaches to refining the binding properties of a...

  1. Ordinary differential equations in affine geometry

    Directory of Open Access Journals (Sweden)

    Salvador Gigena

    1996-05-01

    Full Text Available The method of qualitative analysis is used, as applied to a class of fourth order, nonlinear ordinary differential equations, in order to classify, both locally and globally, two classes of hypersurfaces of decomposable type in affine geometry: those with constant unimodular affine mean curvature L , and those with constant Riemannian scalar curvature R. This allows to provide a large number of new examples of hypersurfaces in affine geometry.

  2. Ordinary differential equations in affine geometry

    OpenAIRE

    Salvador Gigena

    1996-01-01

    The method of qualitative analysis is used, as applied to a class of fourth order, nonlinear ordinary differential equations, in order to classify, both locally and globally, two classes of hypersurfaces of decomposable type in affine geometry: those with constant unimodular affine mean curvature L , and those with constant Riemannian scalar curvature R. This allows to provide a large number of new examples of hypersurfaces in affine geometry.

  3. Absence of direct relationship between intraperitoneal cellular influx and resistance to experimental peritonitis.

    Science.gov (United States)

    Van Geertruyden, N; De Wilde, J P; Bournonville, B; Struelens, M; Kinnaert, P

    1998-08-01

    Intraperitoneal inflammation is an essential defence mechanism against microbial invasion of the abdominal cavity. We have recently demonstrated that a single contact with heat killed E. Coli or Staphylococcus aureus increased the intraabdominal leukocyte influx in rats later challenged by these microorganisms. The aim of the present study was to investigate some of the mechanisms of this phenomenon and to determine its effect on rats survival in an experimental model of peritonitis. The intraabdominal influx of leukocytes following intraperitoneal injection of E. coli, Pseudomonas aeruginosa or Staphylococcus was stimulated by previous intraperitoneal injection of heat killed microbes. The phenomenon was not specific, pretreatment with E. Coli enhanced the intraperitoneal inflammatory reaction against Pseudomonas and vice versa. On the contrary, pretreating the rats with heat killed microorganisms specifically improved their survival after induction of peritonitis with live bacteria, there was no cross-protection. Heat killed staphylococcus aureus which stimulated a subsequent inflammatory reaction against heat killed E. Coli had no effect on the mortality rates of E. Coli peritonitis. In conclusion, there is no direct relationship between resistance to peritonitis and the amount of leukocytes migrating into the abdominal cavity. PMID:9779236

  4. Calcium influx through CRAC channels controls actin organization and dynamics at the immune synapse.

    Science.gov (United States)

    Hartzell, Catherine A; Jankowska, Katarzyna I; Burkhardt, Janis K; Lewis, Richard S

    2016-01-01

    T cell receptor (TCR) engagement opens Ca(2+) release-activated Ca(2+) (CRAC) channels and triggers formation of an immune synapse between T cells and antigen-presenting cells. At the synapse, actin reorganizes into a concentric lamellipod and lamella with retrograde actin flow that helps regulate the intensity and duration of TCR signaling. We find that Ca(2+) influx is required to drive actin organization and dynamics at the synapse. Calcium acts by promoting actin depolymerization and localizing actin polymerization and the actin nucleation promotion factor WAVE2 to the periphery of the lamellipod while suppressing polymerization elsewhere. Ca(2+)-dependent retrograde actin flow corrals ER tubule extensions and STIM1/Orai1 complexes to the synapse center, creating a self-organizing process for CRAC channel localization. Our results demonstrate a new role for Ca(2+) as a critical regulator of actin organization and dynamics at the synapse, and reveal potential feedback loops through which Ca(2+) influx may modulate TCR signaling. PMID:27440222

  5. Calcium influx through CRAC channels controls actin organization and dynamics at the immune synapse

    Science.gov (United States)

    Hartzell, Catherine A; Jankowska, Katarzyna I; Burkhardt, Janis K; Lewis, Richard S

    2016-01-01

    T cell receptor (TCR) engagement opens Ca2+ release-activated Ca2+ (CRAC) channels and triggers formation of an immune synapse between T cells and antigen-presenting cells. At the synapse, actin reorganizes into a concentric lamellipod and lamella with retrograde actin flow that helps regulate the intensity and duration of TCR signaling. We find that Ca2+ influx is required to drive actin organization and dynamics at the synapse. Calcium acts by promoting actin depolymerization and localizing actin polymerization and the actin nucleation promotion factor WAVE2 to the periphery of the lamellipod while suppressing polymerization elsewhere. Ca2+-dependent retrograde actin flow corrals ER tubule extensions and STIM1/Orai1 complexes to the synapse center, creating a self-organizing process for CRAC channel localization. Our results demonstrate a new role for Ca2+ as a critical regulator of actin organization and dynamics at the synapse, and reveal potential feedback loops through which Ca2+ influx may modulate TCR signaling. DOI: http://dx.doi.org/10.7554/eLife.14850.001 PMID:27440222

  6. Calcium influx and release mechanism(s) in histamine-induced myometrial contraction in buffaloes.

    Science.gov (United States)

    Sharma, Abhishek; Choudhury, Soumen; Nakade, Udayraj P; Yadav, Rajkumar Singh; Garg, Satish Kumar

    2014-05-01

    The present study was undertaken to characterize the presence of histamine H1R using molecular biology tools and unravel the influx and release mechanism(s) involved in calcium signalling cascades in histamine-induced myometrial contraction in buffaloes. The presence of H1R mRNA transcript and immunoreactive membrane protein in buffalo myometrium was confirmed by RT-PCR and Western blot analysis. Further, histamine produced concentration-dependent (1nM-10μM) contraction in buffalo myometrium with a potency of 7.13±0.11. When myometrial strips were pre-incubated either with Ca(2+) free solution or with nifedipine, a L-type Ca(2+) channel blocker, dose response curve (DRC) of histamine was significantly (PCPA (blocker of sarco-endoplasmic reticulum Ca(2+)-ATPase). Interestingly, following concurrent exposure to U-73122 (a PL-C inhibitor) and nifedipine, the DRC of histamine was significantly (P<0.05) shifted towards left with increase in maximal contraction (126.30±3.36%). Our findings in buffalo uterus thus suggest that influx of extracellular calcium plays a major role in histamine-induced myometrial contraction, while release of intracellular calcium through calcium-release channels of sarcoplasmic reticulum has a minor role. A possible involvement of non-selective cation channels in histamine-induced myometrial contraction cannot be ruled out, and therefore requires further investigations. PMID:24631173

  7. Affine connections, midpoint formation, and point reflection

    DEFF Research Database (Denmark)

    Kock, Anders

    2011-01-01

    We describe some differential-geometric structures in combinatorial terms: namely affine connections and their torsion and curvature, and we show that torsion free affine connections may equivalently be presented in terms of some simpler combinatorial structure: midpoint formation, and point refl...... reflection (geodesic symmetry). The method employed is that of synthetic differential geometry, which is briefly explained.......We describe some differential-geometric structures in combinatorial terms: namely affine connections and their torsion and curvature, and we show that torsion free affine connections may equivalently be presented in terms of some simpler combinatorial structure: midpoint formation, and point...

  8. A Novel Vertex Affinity for Community Detection

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-05

    We propose a novel vertex affinity measure in this paper. The new vertex affinity quantifies the proximity between two vertices in terms of their clustering strength and is ideal for such graph analytics applications as community detection. We also developed a framework that combines simple graph searches and resistance circuit formulas to compute the vertex affinity efficiently. We study the properties of the new affinity measure empirically in comparison to those of other popular vertex proximity metrics. Our results show that the existing metrics are ill-suited for community detection due to their lack of fundamental properties that are essential for correctly capturing inter- and intra-cluster vertex proximity.

  9. Protein Complex Purification by Affinity Capture.

    Science.gov (United States)

    LaCava, John; Fernandez-Martinez, Javier; Hakhverdyan, Zhanna; Rout, Michael P

    2016-01-01

    Affinity capture has become a powerful technique for consistently purifying endogenous protein complexes, facilitating biochemical and biophysical assays on otherwise inaccessible biological assemblies, and enabling broader interactomic exploration. For this procedure, cells are broken and their contents separated and extracted into a solvent, permitting access to target macromolecular complexes thus released in solution. The complexes are specifically enriched from the extract onto a solid medium coupled with an affinity reagent-usually an antibody-that recognizes the target either directly or through an appended affinity tag, allowing subsequent characterization of the complex. Here, we discuss approaches and considerations for purifying endogenous yeast protein complexes by affinity capture. PMID:27371601

  10. Affine processes on positive semidefinite matrices

    CERN Document Server

    Cuchiero, Christa; Mayerhofer, Eberhard; Teichmann, Josef

    2009-01-01

    This paper provides the mathematical foundation for stochastically continuous affine processes on the cone of positive semidefinite symmetric matrices. These matrix-valued affine processes have arisen from a large and growing range of useful applications in finance, including multi-asset option pricing with stochastic volatility and correlation structures, and fixed-income models with stochastically correlated risk factors and default intensities.

  11. Lectures on extended affine Lie algebras

    CERN Document Server

    Neher, Erhard

    2010-01-01

    We give an introduction to the structure theory of extended affine Lie algebras, which provide a common framework for finite-dimensional semisimple, affine and toroidal Lie algebras. The notes are based on a lecture series given during the Fields Institute summer school at the University of Ottawa in June 2009.

  12. Global affine differential geometry of hypersurfaces

    CERN Document Server

    Li, An-Min; Zhao, Guosong; Hu, Zejun

    2015-01-01

    This book draws a colorful and widespread picture of global affine hypersurface theory up to the most recent state. Moreover, the recent development revealed that affine differential geometry- as differential geometry in general- has an exciting intersection area with other fields of interest, like partial differential equations, global analysis, convex geometry and Riemann surfaces.

  13. Dyes with high affinity for polylactide

    Institute of Scientific and Technical Information of China (English)

    Liang He; Shu Fen Zhang; Bing Tao Tang; Li Li Wang; Jin Zong Yang

    2007-01-01

    Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes.The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.

  14. Free C+ actions on affine threefolds

    OpenAIRE

    Kraft, H.

    2005-01-01

    We study algebraic actions of the additive group C+ on an affine threefold X and prove a smoothness property for the quotient morphism X -< X//C+. Then, following Shulim Kaliman, we give a proof of the conjecture that every free C+ action on affine 3-space C^3 is a translation.

  15. Porosity of Self-affine Sets

    Institute of Scientific and Technical Information of China (English)

    Lifeng XI

    2008-01-01

    In this paper,it is proved that any self-affine set satisfying the strong separation condition is uniformly porous.The author constructs a self-affine set which is not porous,although the open set condition holds.Besides,the author also gives a C1 iterated function system such that its invariant set is not porous.

  16. On affine non-negative matrix factorization

    DEFF Research Database (Denmark)

    Laurberg, Hans; Hansen, Lars Kai

    2007-01-01

    We generalize the non-negative matrix factorization (NMF) generative model to incorporate an explicit offset. Multiplicative estimation algorithms are provided for the resulting sparse affine NMF model. We show that the affine model has improved uniqueness properties and leads to more accurate...

  17. Phosphopeptide enrichment by immobilized metal affinity chromatography

    DEFF Research Database (Denmark)

    Thingholm, Tine E.; Larsen, Martin R.

    2016-01-01

    Immobilized metal affinity chromatography (IMAC) has been the method of choice for phosphopeptide enrichment prior to mass spectrometric analysis for many years and it is still used extensively in many laboratories. Using the affinity of negatively charged phosphate groups towards positively...

  18. Improving image segmentation by learning region affinities

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Lakshman [Los Alamos National Laboratory; Yang, Xingwei [TEMPLE UNIV.; Latecki, Longin J [TEMPLE UNIV.

    2010-11-03

    We utilize the context information of other regions in hierarchical image segmentation to learn new regions affinities. It is well known that a single choice of quantization of an image space is highly unlikely to be a common optimal quantization level for all categories. Each level of quantization has its own benefits. Therefore, we utilize the hierarchical information among different quantizations as well as spatial proximity of their regions. The proposed affinity learning takes into account higher order relations among image regions, both local and long range relations, making it robust to instabilities and errors of the original, pairwise region affinities. Once the learnt affinities are obtained, we use a standard image segmentation algorithm to get the final segmentation. Moreover, the learnt affinities can be naturally unutilized in interactive segmentation. Experimental results on Berkeley Segmentation Dataset and MSRC Object Recognition Dataset are comparable and in some aspects better than the state-of-art methods.

  19. Reflectable bases for affine reflection systems

    CERN Document Server

    Azam, Saeid; Yousofzadeh, Malihe

    2011-01-01

    The notion of a "root base" together with its geometry plays a crucial role in the theory of finite and affine Lie theory. However, it is known that such a notion does not exist for the recent generalizations of finite and affine root systems such as extended affine root systems and affine reflection systems. As an alternative, we introduce the notion of a "reflectable base", a minimal subset $\\Pi$ of roots such that the non-isotropic part of the root system can be recovered by reflecting roots of $\\Pi$ relative to the hyperplanes determined by $\\Pi$. We give a full characterization of reflectable bases for tame irreducible affine reflection systems of reduced types, excluding types $E_{6,7,8}$. As a byproduct of our results, we show that if the root system under consideration is locally finite then any reflectable base is an integral base.

  20. Fatty acid and drug binding to a low-affinity component of human serum albumin, purified by affinity chromatography

    DEFF Research Database (Denmark)

    Vorum, H; Pedersen, A O; Honoré, B

    1992-01-01

    of two albumin components about 40% of the albumin having high affinity and about 60% having low affinity. By affinity chromatography we succeeded in purifying the low-affinity component from the mixture. The high-affinity component, however, could not be isolated. We further analyzed the fatty acid...... and drug binding abilities of the low-affinity component. The fatty acids decanoate, laurate, myristate and palmitate were bound with higher affinity to the mixture than to the low-affinity component. Diazepam was bound with nearly the same affinity to the low-affinity component as to the albumin mixture...

  1. Theoretical approach to characterize the non-Markovianity and diffusion through the influx of the information

    Science.gov (United States)

    Berrada, K.

    2016-08-01

    In this paper, we study the Fisher information for a quantum system consisting of two identical qubits, each of them locally interacting with a bosonic reservoir in the same environment for non-Markovian open, dissipative quantum system. Based on the influx of the information, we propose an information-theoretical approach for characterizing the time-dependent memory effect of environment and diffusion function under the effect of the physical parameters. More precisely, an interesting monotonic relation between the time derivative of quantum Fisher information (QFI) and diffusion function behavior is observed during the time evolution. The phenomenon is that the QFI, namely the precision of estimation, changes dramatically with the environment structure. The dependence of the physical parameters shows that the increasing in the temperature will damage the amount of the QFI with respect of the ratio between the reservoir cutoff frequency and the system oscillation frequency.

  2. Regulatory volume decrease in cardiomyocytes is modulated by calcium influx and reactive oxygen species.

    Science.gov (United States)

    Rojas-Rivera, Diego; Díaz-Elizondo, Jessica; Parra, Valentina; Salas, Daniela; Contreras, Ariel; Toro, Barbra; Chiong, Mario; Olea-Azar, Claudio; Lavandero, Sergio

    2009-11-01

    We investigated the role of Ca(2+) in generating reactive oxygen species (ROS) induced by hyposmotic stress (Hypo) and its relationship to regulatory volume decrease (RVD) in cardiomyocytes. Hypo-induced increases in cytoplasmic and mitochondrial Ca(2+). Nifedipine (Nife) inhibited both Hypo-induced Ca(2+) and ROS increases. Overexpression of catalase (CAT) induced RVD and a decrease in Hypo-induced blebs. Nife prevented CAT-dependent RVD activation. These results show a dual role of Hypo-induced Ca(2+) influx in the control of cardiomyocyte viability. Hypo-induced an intracellular Ca(2+) increase which activated RVD and inhibited necrotic blebbing thus favoring cell survival, while simultaneously increasing ROS generation, which in turn inhibited RVD and induced necrosis.

  3. ADAPTATION OF THE CARTER-TRACY WATER INFLUX CALCULATION TO GROUNDWATER FLOW SIMULTATION.

    Science.gov (United States)

    Kipp, Kenneth L.

    1986-01-01

    The Carter-Tracy calculation for water influx is adapted to groundwater flow simulation with additional clarifying explanation not present in the original papers. The Van Everdingen and Hurst aquifer-influence functions for radial flow from an outer aquifer region are employed. This technique, based on convolution of unit-step response functions, offers a simple but approximate method for embedding an inner region of groundwater flow simulation within a much larger aquifer region where flow can be treated in an approximate fashion. The use of aquifer-influence functions in groundwater flow modeling reduces the size of the computational grid with a corresponding reduction in computer storage and execution time. The Carter-Tracy approximation to the convolution integral enables the aquifer influence function calculation to be made with an additional storage requirement of only two times the number of boundary nodes more than that required for the inner region simulation.

  4. Quantitative study on La3+ influx mediated by sodium-calcium exchanger in human lymphocytes

    Institute of Scientific and Technical Information of China (English)

    魏春英; 杨频

    2002-01-01

    Whether La3+ can enter human peripheral blood lymphocytes by the Na+/Ca2+ exchanger or not and the effect of La3+ on the Na+/Ca2+ exchanger activity are examined by fura-2 technique. And that whether La3+ is sequestered by intracellular organelles (mainly endoplasmic reticulum and mitochondria) is studied by this method. La3+ uptake is obviously stimulated by pretreating the cells with ouabain and by removing extracellular Na+, and intracellular La3+ concentration ([La3+]i) is directly proportional to its extracellular concentration ([La3+]o). But when [La3+]o exceeds 0.4 mmol/L, the 340/380 nm ratio of fluorescence is no longer varied and the maximum [La3+]i is 1.5×10-12 mol@L-1. The higher concentration of La3+ (0.1 mmol/L) increases Na+/Ca2+ exchange-mediated calcium influx, but lower concentration (10 mmol/L) appears to block calcium influx. The results also suggest that cytosolic La3+ is transported by the ATP-dependent Ca2+ pump. Intracellular Ca2+ stores are depleted by ionomycin, and then ionomycin is added again during the period of La3+ uptake, the 340/380 nm ratio of fluorescence is also increased, these results indicate that La3+ is sequestered by intracellular organelles. A characterization of fura-2-La3+ interaction in solution simulating intracellular ionic composition (pH 7.05) shows that La3+ forms a 1:1 fura-2-La3+complex, and the apparent dissociation constant of La3+ for fura-2 (Kd) is 1.7×10-12 mol@L-1. In addition, the limit of detection of fura-2 for La3+ and Ca2+ is 10?12 and 10?8 mol@L-1 respectively.

  5. Jujuboside B Reduces Vascular Tension by Increasing Ca2+ Influx and Activating Endothelial Nitric Oxide Synthase.

    Science.gov (United States)

    Zhao, Yixiu; Zhang, Xin; Li, Jiannan; Bian, Yu; Sheng, Miaomiao; Liu, Bin; Fu, Zidong; Zhang, Yan; Yang, Baofeng

    2016-01-01

    Jujuboside B has been reported to have protective effect on many cardiovascular diseases. However, the effects of Jujuboside B on vascular tension and endothelial function are unknown. The present study investigated the effects of Jujuboside B on reducing vascular tension, protecting endothelial function and the potential mechanisms. The tension of isolated rat thoracic aorta ring was measured by Wire myograph system. The concentration of nitric oxide (NO) and the activity of endothelial nitric oxide synthase (eNOS) in human aortic endothelial cells (HAECs) were determined by Griess reagent method and enzyme-linked immune sorbent assay. The protein levels of eNOS and p-eNOS at Serine-1177 were determined by western blot analysis. Intracellular Ca2+ concentration in HAECs was measured by laser confocal imaging microscopy. Results showed that Jujuboside B reduced the tension of rat thoracic aorta rings with intact endothelium in a dose-dependent manner. L-NAME, KN93, EGTA, SKF96365, iberiotoxin and glibenclamide significantly attenuated Jujuboside B-induced vasodilation in endothelium-intact tissues. In contrast, indometacin and 4-DAMP had no such effects. Jujuboside B also promoted NO generation and increased eNOS activity, which were attenuated by L-NAME, EGTA and SKF96365. Moreover, Jujuboside B increased intracellular Ca2+ concentration dose-dependently, which was inhibited by EGTA and SKF96365. Besides, Jujuboside B induced a rapid Ca2+ influx instantaneously after depleting intracellular Ca2+ store, which was significantly inhibited by SKF96365. In conclusion, this study preliminarily confirmed that Jujuboside B reduced vascular tension endothelium-dependently. The underlying mechanisms involved that Jujuboside B increased extracellular Ca2+ influx through endothelial transient receptor potential cation (TRPC) channels, phosphorylated eNOS and promoted NO generation in vascular endothelial cells. In addition, Jujuboside B-induced vasodilation involved

  6. PKA controls calcium influx into motor neurons during a rhythmic behavior.

    Directory of Open Access Journals (Sweden)

    Han Wang

    Full Text Available Cyclic adenosine monophosphate (cAMP has been implicated in the execution of diverse rhythmic behaviors, but how cAMP functions in neurons to generate behavioral outputs remains unclear. During the defecation motor program in C. elegans, a peptide released from the pacemaker (the intestine rhythmically excites the GABAergic neurons that control enteric muscle contractions by activating a G protein-coupled receptor (GPCR signaling pathway that is dependent on cAMP. Here, we show that the C. elegans PKA catalytic subunit, KIN-1, is the sole cAMP target in this pathway and that PKA is essential for enteric muscle contractions. Genetic analysis using cell-specific expression of dominant negative or constitutively active PKA transgenes reveals that knockdown of PKA activity in the GABAergic neurons blocks enteric muscle contractions, whereas constitutive PKA activation restores enteric muscle contractions to mutants defective in the peptidergic signaling pathway. Using real-time, in vivo calcium imaging, we find that PKA activity in the GABAergic neurons is essential for the generation of synaptic calcium transients that drive GABA release. In addition, constitutively active PKA increases the duration of calcium transients and causes ectopic calcium transients that can trigger out-of-phase enteric muscle contractions. Finally, we show that the voltage-gated calcium channels UNC-2 and EGL-19, but not CCA-1 function downstream of PKA to promote enteric muscle contractions and rhythmic calcium influx in the GABAergic neurons. Thus, our results suggest that PKA activates neurons during a rhythmic behavior by promoting presynaptic calcium influx through specific voltage-gated calcium channels.

  7. Non-Zenoness of piecewise affine dynamical systems and affine complementarity systems with inputs

    Institute of Scientific and Technical Information of China (English)

    Le Quang THUAN

    2014-01-01

    In the context of continuous piecewise affine dynamical systems and affine complementarity systems with inputs, we study the existence of Zeno behavior, i.e., infinite number of mode transitions in a finite-length time interval, in this paper. The main result reveals that continuous piecewise affine dynamical systems with piecewise real-analytic inputs do not exhibit Zeno behavior. Applied the achieved result to affine complementarity systems with inputs, we also obtained a similar conclusion. A direct benefit of the main result is that one can apply smooth ordinary differential equations theory in a local manner for the analysis of continuous piecewise affine dynamical systems with inputs.

  8. Involvement of IP3-receptor activation in endothelin-1-induced Ca(2+) influx in rat pulmonary small artery.

    Science.gov (United States)

    Kato, K; Okamura, K; Hatta, M; Morita, H; Kajioka, S; Naito, S; Yamazaki, J

    2013-11-15

    We examined the endothelin-1 (ET-1)-induced increase in the intracellular free Ca(2+) concentration ([Ca(2+)]i) in fura-2-loaded rat pulmonary small arteries. ET-1 (30 nM) elicited a long-lasting increase in [Ca(2+)]i in physiological salt solution (PSS). In subsequent experiments, arteries were pretreated with BQ-788, an ETB-specific blocker, to allow us to focus on responses mediated via the ETA receptor, the existence of which was confirmed by immunohistochemistry. In Ca(2+)-free PSS, ET-1 evoked a small transient increase in [Ca(2+)]i, indicating Ca(2+) release from the SR (sarcoplasmic reticulum). After a switch to PSS (containing 2mM CaCl2), ET-1 elicited a long-lasting increase in [Ca(2+)]i that was not inhibited by 1 μM nicardipine, an L-type Ca(2+)-channel inhibitor, suggesting involvement of a Ca(2+)-influx pathway independent of that channel. In arteries preincubated with 30 μM cyclopiazonic acid (CPA) or 2 μM thapsigargin (TG), the ET-1-induced Ca(2+)-release was greatly reduced, and the induced Ca(2+)-influx was attenuated. U-73122, a phospholipase C (PLC) inhibitor, had inhibitory effects similar to those of CPA and TG on the ET-1-induced Ca(2+)-release and Ca(2+)-influx, whereas U-73343, an inactive analogue of U-73122, had no such effects. Two putative membrane-permeable IP3-receptor blockers, 2-aminoethoxydiphenyl borate (2APB, 50 μM) and Xestospongin C (20 μM), (a) almost completely inhibited the ET-1-induced Ca(2+)-release and Ca(2+)-influx, and (b) reduced the ET-1-induced contraction. These results indicate that in rat pulmonary small arteries, ET-1 induces receptor-operated Ca(2+) influx via the ETA receptor, and that this influx interacts with InsP3-receptor activation. PMID:24157978

  9. Estrone-1-sulphate (E1S) has impact on the kinetics parameters of transporter mediated taurine and glutamate influx in Caco-2 cells

    DEFF Research Database (Denmark)

    Steffansen, Bente; El-Sayed, F

    membrane transporters. The aim was therefore to investigate if addition of E1S to the growth medium of Caco-2 cells before but not during the influx study, change the kinetic parameters of transporter-mediated influx of taurine and glutamate by respective TAUT and EAAT transporters. The results show that 4...... days pretreatment with E1S change the concentration dependent influx curves and Km for transporter mediated taurine and Km and Jmax for glutamate influx although the effects on Km and Jmax are not significant....

  10. Affinity Proteomics in the mountains: Alpbach 2015.

    Science.gov (United States)

    Taussig, Michael J

    2016-09-25

    The 2015 Alpbach Workshop on Affinity Proteomics, organised by the EU AFFINOMICS consortium, was the 7th workshop in this series. As in previous years, the focus of the event was the current state of affinity methods for proteome analysis, including complementarity with mass spectrometry, progress in recombinant binder production methods, alternatives to classical antibodies as affinity reagents, analysis of proteome targets, industry focus on biomarkers, and diagnostic and clinical applications. The combination of excellent science with Austrian mountain scenery and winter sports engender an atmosphere that makes this series of workshops exceptional. The articles in this Special Issue represent a cross-section of the presentations at the 2015 meeting. PMID:27118167

  11. Optimized Affinity Capture of Yeast Protein Complexes.

    Science.gov (United States)

    LaCava, John; Fernandez-Martinez, Javier; Hakhverdyan, Zhanna; Rout, Michael P

    2016-01-01

    Here, we describe an affinity isolation protocol. It uses cryomilled yeast cell powder for producing cell extracts and antibody-conjugated paramagnetic beads for affinity capture. Guidelines for determining the optimal extraction solvent composition are provided. Captured proteins are eluted in a denaturing solvent (sodium dodecyl sulfate polyacrylamide gel electrophoresis sample buffer) for gel-based proteomic analyses. Although the procedures can be modified to use other sources of cell extract and other forms of affinity media, to date we have consistently obtained the best results with the method presented. PMID:27371596

  12. Affinization of category O for quantum groups

    CERN Document Server

    Young, C A S

    2012-01-01

    Let g be a simple Lie algebra. We consider the category O-hat of those modules over the affine quantum group Uq(g-hat) whose Uq(g)-weights have finite multiplicity and lie in a finite union of cones generated by negative roots. We show that many properties of the category of the finite-dimensional representations naturally extend to the category O-hat. In particular, we develop the theory of q-characters and define the minimal affinizations of parabolic Verma modules. In types ABCFG we classify these minimal affinizations and conjecture a Weyl denominator type formula for their characters.

  13. Corner Transfer Matrices and Quantum Affine Algebras

    CERN Document Server

    Foda, O E; Foda, Omar; Miwa, Tetsuji

    1992-01-01

    Let H be the corner-transfer-matrix Hamiltonian for the six-vertex model in the anti-ferroelectric regime. It acts on the infinite tensor product W = V . V . V ....., where is the 2-dimensional irreducible representation of the quantum affine sl(2). We observe that H is the derivation of quantum affine sl(2), and conjecture that the eigenvectors of H form the level-1 vacuum representation of quantum affine sl(2). We report on checks in support of our conjecture.

  14. Simultaneous measurements of magnesium, calcium and sodium influxes in perfused squid giant axons under membrane potential control.

    Science.gov (United States)

    Rojas, E; Taylor, R E

    1975-10-01

    1. Giant axons from the squids Dosidicus gigas, Loligo forbesi and Loligo vulgaris were internally perfused with 550 or 275 mM KF plus sucrose and bathed in artificial sea water containing 45Ca, 28Mg or mixtures of 45Ca-28Mg or 45Ca-22Na. Resting influxes and extra influxes during voltage-clamp pulses were measured by collecting and counting the internal perfusate. 2. For Dosidicus axons in 10 mM-CaCl2 the resting influx of calcium was 0-016 +/- 0-007 p-mole/cm2 sec and a linear function of external concentration. For two experiments in 10 and 84-7 mM-CaCl2, 100 nM tetrodotoxin had no effect. Resting calcium influx in 10 mM-CaCl2 was 0-017 +/- 0-013 p-mole/cm2 sec for Loligo axons. 3. With 55 mM-MgCl2 outside the average resting magnesium influx was 0-124 +/- 0-080 p-mole/cm2 sec for Loligo axons. Discarding one aberrant point the value is 0-105 +/- 0-046 which is not significantly different from the resting calcium influx for Dosidicus fibres in 55 mM-CaCl2, given as 0-094 p-mole/cm2 sec by the regression line shown in Fig. 1. In two experiments 150 nM tetrodotoxin had no effect. 4. With 430 mM-NaCl outside 100 nM tetrodotoxin reduced the average resting influx of sodium in Dosidicus axon from 27-7 +/- 4-5 to 25-1 +/- 6-2 p-mole/cm2 sec and for Loligo fibres in 460 mM-NaCl from 50-5 +/- 4 to 20 +/- 8 p-mole/cm2 sec. 5. Using depolarizing pulses of various durations, the extra calcium influx occurred in two phases. The early phase was eliminated by external application of tetrodotoxin. The results of analysis are consistent with, but do not rigorously demonstrate, the conclusion that the tetrodotoxin sensitive calcium entry is flowing through the normal sodium channels (cf. Baker, Hodgkin & Ridgway, 1971). 6. Measurements of extra influxes using 22Na and 45Ca simultaneously indicate that the time courses of tetrodotoxin sensitive calcium and sodium entry are similar but not necessarily identical. It is very doubtful that any significant calcium entry occurs before

  15. Automorphisms in Birational and Affine Geometry

    CERN Document Server

    Ciliberto, Ciro; Flenner, Hubert; McKernan, James; Prokhorov, Yuri; Zaidenberg, Mikhail

    2014-01-01

    The main focus of this volume is on the problem of describing the automorphism groups of affine and projective varieties, a classical subject in algebraic geometry where, in both cases, the automorphism group is often infinite dimensional. The collection covers a wide range of topics and is intended for researchers in the fields of classical algebraic geometry and birational geometry (Cremona groups) as well as affine geometry with an emphasis on algebraic group actions and automorphism groups. It presents original research and surveys and provides a valuable overview of the current state of the art in these topics. Bringing together specialists from projective, birational algebraic geometry and affine and complex algebraic geometry, including Mori theory and algebraic group actions, this book is the result of ensuing talks and discussions from the conference “Groups of Automorphisms in Birational and Affine Geometry” held in October 2012, at the CIRM, Levico Terme, Italy. The talks at the conference high...

  16. Synthesis of a New Series of Bone Affinity Compounds

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new series of bone affinity compounds were synthesized by linking chrysophanol with 5-fluorouracil derivatives. Their bone affinity was established by hydroxyapafive (HA)affinity experiment in vitro, and their cytostatic effects were shown by the MTT assay.

  17. A MEMS Dielectric Affinity Glucose Biosensor

    OpenAIRE

    Xian HUANG; Li, SiQi; Davis, Erin; Li, Dachao; Wang, Qian; Lin, Qiao

    2013-01-01

    Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose sensor that measured pre-mixed glucose-sensitive polymer solutions at various glucose concent...

  18. On Affine Fusion and the Phase Model

    OpenAIRE

    Walton, Mark A.

    2012-01-01

    A brief review is given of the integrable realization of affine fusion discovered recently by Korff and Stroppel. They showed that the affine fusion of the $su(n)$ Wess-Zumino-Novikov-Witten (WZNW) conformal field theories appears in a simple integrable system known as the phase model. The Yang-Baxter equation leads to the construction of commuting operators as Schur polynomials, with noncommuting hopping operators as arguments. The algebraic Bethe ansatz diagonalizes them, revealing a connec...

  19. Purely affine elementary su(N) fusions

    OpenAIRE

    Rasmussen, Jorgen; Walton, Mark A.

    2001-01-01

    We consider three-point couplings in simple Lie algebras -- singlets in triple tensor products of their integrable highest weight representations. A coupling can be expressed as a linear combination of products of finitely many elementary couplings. This carries over to affine fusion, the fusion of Wess-Zumino-Witten conformal field theories, where the expressions are in terms of elementary fusions. In the case of su(4) it has been observed that there is a purely affine elementary fusion, i.e...

  20. Complete algebraic vector fields on affine surfaces

    OpenAIRE

    Kaliman, Shulim; Kutzschebauch, Frank; Leuenberger, Matthias

    2014-01-01

    Let $\\AAutH (X)$ be the subgroup of the group $\\AutH (X)$ of holomorphic automorphisms of a normal affine algebraic surface $X$ generated by elements of flows associated with complete algebraic vector fields. Our main result is a classification of all normal affine algebraic surfaces $X$ quasi-homogeneous under $\\AAutH (X)$ in terms of the dual graphs of the boundaries $\\bX \\setminus X$ of their SNC-completions $\\bX$.

  1. Fan affinity laws from a collision model

    International Nuclear Information System (INIS)

    The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour of air is incorporated. Our calculations prove the affinity laws and provide numerical estimates of the air delivery, thrust and drag on a rotating fan. (paper)

  2. The contractile vacuole in Ca2+-regulation in Dictyostelium: its essential function for cAMP-induced Ca2+-influx

    Directory of Open Access Journals (Sweden)

    Schlatterer Christina

    2006-06-01

    Full Text Available Abstract Background cAMP-induced Ca2+-influx in Dictyostelium is controlled by at least two non-mitochondrial Ca2+-stores: acidic stores and the endoplasmic reticulum (ER. The acidic stores may comprise the contractile vacuole network (CV, the endosomal compartment and acidocalcisomes. Here the role of CV in respect to function as a potential Ca2+-store was investigated. Results Dajumin-GFP labeled contractile vacuoles were purified 7-fold by anti-GFP-antibodies in a magnetic field. The purified CV were shown for the first time to accumulate and release Ca2+. Release of Ca2+ was elicited by arachidonic acid or the calmodulin antagonist W7, the latter due to inhibition of the pump. The characteristics of Ca2+-transport and Ca2+-release of CV were compared to similarly purified vesicles of the ER labeled by calnexin-GFP. Since the CV proved to be a highly efficient Ca2+-compartment we wanted to know whether or not it takes part in cAMP-induced Ca2+-influx. We made use of the LvsA--mutant expected to display reduced Ca2+-transport due to loss of calmodulin. We found a severe reduction of cAMP-induced Ca2+-influx into whole cells. Conclusion The contractile vacuoles in Dictyostelium represent a highly efficient acidic Ca2+-store that is required for cAMP-induced Ca2+-influx.

  3. In vivo quantification of the unidirectional influx constant for Gd-DTPA diffusion across the myocardial capillaries with MR imaging

    DEFF Research Database (Denmark)

    Larsson, H B; Stubgaard, M; Søndergaard, Lise;

    1994-01-01

    The authors present an in vivo method for measuring the unidirectional influx constant (Ki) for gadolinium diethylenetriaminepentaacetic acid (DTPA) diffusion across the capillary membrane in the human myocardium with magnetic resonance imaging. Ki is related to the extraction fraction (E) and th...

  4. Nitrate and ammonium influxes in soybean (Glycine max) roots : Direct comparison of N-13 and N-15 tracing

    NARCIS (Netherlands)

    Clarkson, DT; Gojon, A; Saker, LR; Wiersema, PK; Purves, JV; Tillard, P; Arnold, GM; Paans, AJM; Vaalburg, W; Stulen, [No Value

    1996-01-01

    We compared influxes and internal transport in soybean plants (Glycine max cv. Kingsoy) of labelled N from external solutions where either ammonium or nitrate was labelled with the stable isotope N-15 and the radioactive isotope N-13. The objective was to see whether mass spectrometric determination

  5. Isolation and functional characterization of an influx silicon transporter in two pumpkin cultivars contrasting in silicon accumulation.

    Science.gov (United States)

    Mitani, Namiki; Yamaji, Naoki; Ago, Yukiko; Iwasaki, Kozo; Ma, Jian Feng

    2011-04-01

    A high accumulation of silicon (Si) is required for overcoming abiotic and biotic stresses, but the molecular mechanisms of Si uptake, especially in dicotyledonous species, is poorly understood. Herein, we report the identification of an influx transporter of Si in two Cucurbita moschata (pumpkin) cultivars greatly differing in Si accumulation, which are used for the rootstocks of bloom and bloomless Cucumis sativus (cucumber), respectively. Heterogeneous expression in both Xenopus oocytes and rice mutant defective in Si uptake showed that the influx transporter from the bloom pumpkin rootstock can transport Si, whereas that from the bloomless rootstock cannot. Analysis with site-directed mutagenesis showed that, among the two amino acid residues differing between the two types of rootstocks, only changing a proline to a leucine at position 242 results in the loss of Si transport activity. Furthermore, all pumpkin cultivars for bloomless rootstocks tested have this mutation. The transporter is localized in all cells of the roots, and investigation of the subcellular localization with different approaches consistently showed that the influx Si transporter from the bloom pumpkin rootstock was localized at the plasma membrane, whereas the one from the bloomless rootstock was localized at the endoplasmic reticulum. Taken together, our results indicate that the difference in Si uptake between two pumpkin cultivars is probably the result of allelic variation in one amino acid residue of the Si influx transporter, which affects the subcellular localization and subsequent transport of Si from the external solution to the root cells.

  6. Legalizing File-Sharing: An Idea Whose Time Has Come - Or Gone? Report from the Information Influx Conference 2014

    NARCIS (Netherlands)

    J.P. Quintais

    2014-01-01

    On 2-4 July 2014 Information Influx, the 25th anniversary conference of the Institute for Information Law (IViR) was held in Amsterdam. Integrated in the conference, on Friday, 4 July a panel entitled "Legalizing file-sharing: an idea whose time has come - or gone?" met. The panel’s moderator was Pr

  7. Jujuboside B Reduces Vascular Tension by Increasing Ca2+ Influx and Activating Endothelial Nitric Oxide Synthase.

    Directory of Open Access Journals (Sweden)

    Yixiu Zhao

    Full Text Available Jujuboside B has been reported to have protective effect on many cardiovascular diseases. However, the effects of Jujuboside B on vascular tension and endothelial function are unknown. The present study investigated the effects of Jujuboside B on reducing vascular tension, protecting endothelial function and the potential mechanisms. The tension of isolated rat thoracic aorta ring was measured by Wire myograph system. The concentration of nitric oxide (NO and the activity of endothelial nitric oxide synthase (eNOS in human aortic endothelial cells (HAECs were determined by Griess reagent method and enzyme-linked immune sorbent assay. The protein levels of eNOS and p-eNOS at Serine-1177 were determined by western blot analysis. Intracellular Ca2+ concentration in HAECs was measured by laser confocal imaging microscopy. Results showed that Jujuboside B reduced the tension of rat thoracic aorta rings with intact endothelium in a dose-dependent manner. L-NAME, KN93, EGTA, SKF96365, iberiotoxin and glibenclamide significantly attenuated Jujuboside B-induced vasodilation in endothelium-intact tissues. In contrast, indometacin and 4-DAMP had no such effects. Jujuboside B also promoted NO generation and increased eNOS activity, which were attenuated by L-NAME, EGTA and SKF96365. Moreover, Jujuboside B increased intracellular Ca2+ concentration dose-dependently, which was inhibited by EGTA and SKF96365. Besides, Jujuboside B induced a rapid Ca2+ influx instantaneously after depleting intracellular Ca2+ store, which was significantly inhibited by SKF96365. In conclusion, this study preliminarily confirmed that Jujuboside B reduced vascular tension endothelium-dependently. The underlying mechanisms involved that Jujuboside B increased extracellular Ca2+ influx through endothelial transient receptor potential cation (TRPC channels, phosphorylated eNOS and promoted NO generation in vascular endothelial cells. In addition, Jujuboside B-induced vasodilation

  8. The connection between metal ion affinity and ligand affinity in integrin I domains

    DEFF Research Database (Denmark)

    Vorup-Jensen, Thomas; Waldron, TT; Astrof, N;

    2007-01-01

    Integrins are cell-surface heterodimeric proteins that mediate cell-cell, cell-matrix, and cell-pathogen interactions. Half of the known integrin alpha subunits contain inserted domains (I domains) that coordinate ligand through a metal ion. Although the importance of conformational changes within...... isolated I domains in regulating ligand binding has been reported, the relationship between metal ion binding affinity and ligand binding affinity has not been elucidated. Metal and ligand binding by several I domain mutants that are stabilized in different conformations are investigated using isothermal...... titration calorimetry and surface plasmon resonance studies. This work suggests an inverse relationship between metal ion affinity and ligand binding affinity (i.e. constructs with a high affinity for ligand exhibit a low affinity for metal). This trend is discussed in the context of structural studies...

  9. Affine modifications and affine hypersurfaces with a very transitive automorphism group

    OpenAIRE

    Kaliman, Shulim; ZAIDENBERG, MIKHAIL

    1998-01-01

    We study a kind of modification of an affine domain which produces another affine domain. First appeared in passing in the basic paper of O. Zariski (1942), it was further considered by E.D. Davis (1967). The first named author applied its geometric counterpart to construct contractible smooth affine varieties non-isomorphic to Euclidean spaces. Here we provide certain conditions which guarantee preservation of the topology under a modification. As an application, we show that the group of bi...

  10. Paraoxon Attenuates Vascular Smooth Muscle Contraction through Inhibiting Ca2+ Influx in the Rabbit Thoracic Aorta

    Directory of Open Access Journals (Sweden)

    Shouhong Zhou

    2010-01-01

    Full Text Available We investigated the effect of paraoxon on vascular contractility using organ baths in thoracic aortic rings of rabbits and examined the effect of paraoxon on calcium homeostasis using a whole-cell patch-clamp technique in isolated aortic smooth muscle cells of rabbits. The findings show that administration of paraoxon (30 μM attenuated thoracic aorta contraction induced by phenylephrine (1 μM and/or a high K+ environment (80 mM in both the presence and absence of thoracic aortic endothelium. This inhibitory effect of paraoxon on vasoconstrictor-induced contraction was abolished in the absence of extracellular Ca2+, or in the presence of the Ca2+ channel inhibitor, verapamil. But atropine had little effect on the inhibitory effect of paraoxon on phenylephrine-induced contraction. Paraoxon also attenuated vascular smooth muscle contraction induced by the cumulative addition of CaCl2 and attenuated an increase of intracellular Ca2+ concentration induced by K+ in vascular smooth muscle cells. Moreover, paraoxon (30 μM inhibited significantly L-type calcium current in isolated aortic smooth muscle cells of rabbits. In conclusion, our results demonstrate that paraoxon attenuates vasoconstrictor-induced contraction through inhibiting Ca2+ influx in the rabbits thoracic aorta.

  11. Triggered Ca2+ influx is required for extended synaptotagmin 1-induced ER-plasma membrane tethering.

    Science.gov (United States)

    Idevall-Hagren, Olof; Lü, Alice; Xie, Beichen; De Camilli, Pietro

    2015-09-01

    The extended synaptotagmins (E-Syts) are ER proteins that act as Ca(2+)-regulated tethers between the ER and the plasma membrane (PM) and have a putative role in lipid transport between the two membranes. Ca(2+) regulation of their tethering function, as well as the interplay of their different domains in such function, remains poorly understood. By exposing semi-intact cells to buffers of variable Ca(2+) concentrations, we found that binding of E-Syt1 to the PI(4,5)P2-rich PM critically requires its C2C and C2E domains and that the EC50 of such binding is in the low micromolar Ca(2+) range. Accordingly, E-Syt1 accumulation at ER-PM contact sites occurred only upon experimental manipulations known to achieve these levels of Ca(2+) via its influx from the extracellular medium, such as store-operated Ca(2+) entry in fibroblasts and membrane depolarization in β-cells. We also show that in spite of their very different physiological functions, membrane tethering by E-Syt1 (ER to PM) and by synaptotagmin (secretory vesicles to PM) undergo a similar regulation by plasma membrane lipids and cytosolic Ca(2+).

  12. Modeling the Global micrometeor influx into the Mesosphere/Lower Thermosphere using radar measurements

    Science.gov (United States)

    Janches, D.; Heinselman, C.; Chandran, A.; Chau, J. L.

    We discuss initial results from an effort to model the annual and global micrometeor influx into the Mesosphere Lower Thermosphere MLT atmospheric region based on very precise meteor head-echo radar observations The principal goal of this effort is to construct a new and more precise sporadic meteoric input function needed for the subsequent modeling of the atmospheric chemistry of the meteoric material and the origin and formation of metal layers in the MLT Modeling this function requires precise knowledge of the meteor directionality velocity distributions mass flux and diurnal and or annual variability of the sporadic micrometeoroid environment The model is constructed based on meteor radar observations obtained with the 430 MHz dual-beam Arecibo AO radar in Puerto Rico and the 50 MHz Jicamarca JRO radar in Peru We also compare the modeled fluxes with observations from the 1 29 GHz Sondrestrom radar in Greenland thus utilizing almost the entire NSF ISR chain The model uses Monte Carlo simulation techniques and at present assumes that most of the detected particles originate from three radiant distributions The most dominant meteor source has a radiant distribution concentrated around the Earth s apex The other two sources are centered 80 degrees in ecliptic longitude to each side of the Apex and are commonly known as Helion and Anti-Helion Each source is introduced with its characteristic particle geocentric velocity distribution To reproduce the measurements the Apex source flux was set to three times as many particles as the

  13. A Semi-Annual Study of the Micrometeor Influx in the Mesopause

    Science.gov (United States)

    Janches, D.; Nolan, M. C.; Mathews, J. D.; Meisel, D. D.

    2003-12-01

    We present and discuss results from the first six months of a year-long observation campaign of the micrometeor influx in the upper atmosphere using the dual-beam 430 MHz Arecibo Observatory radar. The AO radar detects decelerating particles in the size range 0.5-100 microns for which precise altitude; instantaneous Doppler velocity (rms errors of the order of 10-100 m/sec) and (constant) deceleration are obtained. This provides a tool for the study of a mass-region of the interplanetary dust distribution and its influence to the mesopause that was previously inaccessible to ground-based instruments and helps bridge the gap between spacecraft dust measurements and traditional meteor radar capabilities. The meteor rate detected inside the 305 m-diameter radar beam peaks at sunrise ( ˜40 events per minute) when the radar points near the apex. We find the meteor flux rate as well as the geocentric velocity distribution to be strongly dependent on the topocentric declination implying a function with radiant ecliptic latitude. In addition, we present estimations of the total micrometeor mass flux derived from these observations, resulting in ˜2000 tons of meteoric material deposited over the whole earth each year in the 80-120 km altitude region. Preliminary results also show that the mass flux peaks in June (i.e. a function of ecliptic longitude) in agreement with diurnal measurements of metallic densities derived from lidar observations.

  14. Carbon influx in He and D plasmas in DIII-D

    International Nuclear Information System (INIS)

    Differences in the carbon behavior between He and D plasmas during VH-mode, L-mode and L-mode with excess gas puffing are reported and inferences on the importance of the various carbon sources during these modes of operation are discussed. During a VH-mode phase, VUV and visible charge exchange spectroscopy indicates that for both He and D operation the carbon behavior is very similar. In the edge plasma, carbon build up is quite rapid, and the carbon influx represents a large fraction of the total plasma density increase until the termination of the VH phase. During cold divertor operation induced by puffing the primary fueling gas, D and He discharges show a difference in the carbon behavior. The core carbon density is seen to be approximately constant during a D discharge as it transitions from an attached to a cold divertor. However in a He discharge, the core carbon density disappears soon after the cold divertor transition. Arguments are made that the primary carbon source in the ELM free H-mode period is physical sputtering by ion impact at the divertor strike point. In L-mode, both attached and cold divertor, the primary source is from the divertor region and two possibilities for this source are chemical sputtering or charge neutral sputtering. Existing data supports charge exchange neutrals as dominant

  15. Functional expression of nicotine influx transporter in A549 human alveolar epithelial cells.

    Science.gov (United States)

    Tega, Yuma; Yuzurihara, Chihiro; Kubo, Yoshiyuki; Akanuma, Shin-ichi; Ehrhardt, Carsten; Hosoya, Ken-ichi

    2016-02-01

    Nicotine is a potent addictive alkaloid, and is rapidly absorbed through the alveoli of the lung. However, the transport mechanism of nicotine at the human alveolar epithelial barrier has not been investigated in great detail. In the present study, the transport mechanism of nicotine across alveolar epithelium was investigated in vitro using A549 cells, a human adenocarcinoma-derived cell line with an alveolar epithelial cell like phenotype. Nicotine uptake by A549 cells exhibited time-, temperature-, and concentration-dependence with a Km of 50.4 μM. These results suggest that a carrier-mediated transport process is involved in nicotine transport in human alveolar epithelial cells. Nicotine uptake by A549 cells was insensitive to change in extracellular pH. Moreover, nicotine uptake by A549 cells could be inhibited by organic cations such as verapamil and pyrilamine, but not typical substrates of organic cation transporters and β2-agonist. These results suggest that a novel, not yet molecularly identified, organic cation transporter plays a role in nicotine transport which is unlikely to interact with β2-agonist transport. This nicotine influx transporter in human alveolar epithelium might have implications for the rapid absorption of nicotine into the systemic circulation. PMID:26830082

  16. Affinity purification of aprotinin from bovine lung.

    Science.gov (United States)

    Xin, Yu; Liu, Lanhua; Chen, Beizhan; Zhang, Ling; Tong, Yanjun

    2015-05-01

    An affinity protocol for the purification of aprotinin from bovine lung was developed. To simulate the structure of sucrose octasulfate, a natural specific probe for aprotinin, the affinity ligand was composed of an acidic head and a hydrophobic stick, and was then linked with Sepharose. The sorbent was then subjected to adsorption analysis with pure aprotinin. The purification process consisted of one step of affinity chromatography and another step of ultrafiltration. Then purified aprotinin was subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis, trypsin inhibitor activity, gel-filtration, and thin-layer chromatography analysis. As calculated, the theoretical maximum adsorption (Qmax ) of the affinity sorbent was 25,476.0 ± 184.8 kallikrein inactivator unit/g wet gel; the dissociation constant of the complex "immobilized ligand-aprotinin" (Kd ) was 4.6 ± 0.1 kallikrein inactivator unit/mL. After the affinity separation of bovine lung aprotinin, reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and gel-filtration chromatography revealed that the protein was a single polypeptide, and the purities were ∼ 97 and 100%, respectively; the purified peptide was also confirmed with aprotinin standard by gel-filtration chromatography and thin-layer chromatography. After the whole purification process, protein, and bioactivity recoveries were 2.2 and 92.6%, respectively; and the specific activity was up to 15,907.1 ± 10.2 kallikrein inactivator unit/mg. PMID:25677462

  17. Classification of neocortical interneurons using affinity propagation

    Science.gov (United States)

    Santana, Roberto; McGarry, Laura M.; Bielza, Concha; Larrañaga, Pedro; Yuste, Rafael

    2013-01-01

    In spite of over a century of research on cortical circuits, it is still unknown how many classes of cortical neurons exist. In fact, neuronal classification is a difficult problem because it is unclear how to designate a neuronal cell class and what are the best characteristics to define them. Recently, unsupervised classifications using cluster analysis based on morphological, physiological, or molecular characteristics, have provided quantitative and unbiased identification of distinct neuronal subtypes, when applied to selected datasets. However, better and more robust classification methods are needed for increasingly complex and larger datasets. Here, we explored the use of affinity propagation, a recently developed unsupervised classification algorithm imported from machine learning, which gives a representative example or exemplar for each cluster. As a case study, we applied affinity propagation to a test dataset of 337 interneurons belonging to four subtypes, previously identified based on morphological and physiological characteristics. We found that affinity propagation correctly classified most of the neurons in a blind, non-supervised manner. Affinity propagation outperformed Ward's method, a current standard clustering approach, in classifying the neurons into 4 subtypes. Affinity propagation could therefore be used in future studies to validly classify neurons, as a first step to help reverse engineer neural circuits. PMID:24348339

  18. Stepparents' Affinity-Seeking and Affinity-Maintaining Strategies with Stepchildren.

    Science.gov (United States)

    Ganong, Lawrence; Coleman, Marilyn; Fine, Mark; Martin, Patricia

    1999-01-01

    Examines the strategies that stepparents use to develop and maintain affinity with stepchildren and the effects that these strategies have on the development of stepparent-stepchildren relationships. Thirty-one affinity-seeking strategies are identified. Results show that dyadic activities worked best, but it is important that stepchildren…

  19. On Affine Fusion and the Phase Model

    Directory of Open Access Journals (Sweden)

    Mark A. Walton

    2012-11-01

    Full Text Available A brief review is given of the integrable realization of affine fusion discovered recently by Korff and Stroppel. They showed that the affine fusion of the su(n Wess-Zumino-Novikov-Witten (WZNW conformal field theories appears in a simple integrable system known as the phase model. The Yang-Baxter equation leads to the construction of commuting operators as Schur polynomials, with noncommuting hopping operators as arguments. The algebraic Bethe ansatz diagonalizes them, revealing a connection to the modular S matrix and fusion of the su(n WZNW model. The noncommutative Schur polynomials play roles similar to those of the primary field operators in the corresponding WZNW model. In particular, their 3-point functions are the su(n fusion multiplicities. We show here how the new phase model realization of affine fusion makes obvious the existence of threshold levels, and how it accommodates higher-genus fusion.

  20. Affinity chromatography of bacterial lactate dehydrogenases.

    Science.gov (United States)

    Kelly, N; Delaney, M; O'Carra, P

    1978-06-01

    The affinity system used was the immobilized oxamate derivative previously used to purify mammalian lactate dehydrogenases. The bacterial dehydrogenases specific for the L-stereoisomer of lactate behaved in the same way as the mammalian enzymes, binding strongly in the presence of NADH. The D-lactate-specific enzymes, however, did not show any biospecific affinity for this gel. The L-specific enzymes could be purified to homogeneity in one affinity-chromatographic step. The D-specific enzymes could be efficiently separated from the L-specific ones and could then be further purified on an immobilized NAD derivative. The mechanism of activation of the lactate dehydrogenase from Streptococcus faecalis by fructose 1,6-bisphosphate was investigated by using the immobilized oxamate gel. PMID:666726

  1. European and international collaboration in affinity proteomics.

    Science.gov (United States)

    Stoevesandt, Oda; Taussig, Michael J

    2012-06-15

    In affinity proteomics, specific protein-binding molecules (a.k.a. binders), principally antibodies, are applied as reagents in proteome analysis. In recent years, advances in binder technologies have created the potential for an unprecedented view on protein expression and distribution patterns in plasma, cells and tissues and increasingly on protein function. Particular strengths of affinity proteomics methods include detecting proteins in their natural environments of cell or tissue, high sensitivity and selectivity for detection of low abundance proteins and exploiting binding actions such as functional interference in living cells. To maximise the use and impact of affinity reagents, it will be essential to create comprehensive, standardised binder collections. With this in mind, the EU FP7 programme AFFINOMICS (http://www.affinomics.org), together with the preceding EU programmes ProteomeBinders and AffinityProteome, aims to extend affinity proteomics research by generating a large-scale resource of validated protein-binding molecules for characterisation of the human proteome. Activity is directed at producing binders to about 1000 protein targets, primarily in signal transduction and cancer, by establishing a high throughput, coordinated production pipeline. An important aspect of AFFINOMICS is the development of highly efficient recombinant selection methods, based on phage, cell and ribosome display, capable of producing high quality binders at greater throughput and lower cost than hitherto. The programme also involves development of innovative and sensitive technologies for specific detection of target proteins and their interactions, and deployment of binders in proteomics studies of clinical relevance. The need for such binder generation programmes is now recognised internationally, with parallel initiatives in the USA for cancer (NCI) and transcription factors (NIH) and within the Human Proteome Organisation (HUPO). The papers in this volume of New

  2. TRP, TRPL and cacophony channels mediate Ca2+ influx and exocytosis in photoreceptors axons in Drosophila.

    Directory of Open Access Journals (Sweden)

    Guadalupe Astorga

    Full Text Available In Drosophila photoreceptors Ca(2+-permeable channels TRP and TRPL are the targets of phototransduction, occurring in photosensitive microvilli and mediated by a phospholipase C (PLC pathway. Using a novel Drosophila brain slice preparation, we studied the distribution and physiological properties of TRP and TRPL in the lamina of the visual system. Immunohistochemical images revealed considerable expression in photoreceptors axons at the lamina. Other phototransduction proteins are also present, mainly PLC and protein kinase C, while rhodopsin is absent. The voltage-dependent Ca(2+ channel cacophony is also present there. Measurements in the lamina with the Ca(2+ fluorescent protein G-CaMP ectopically expressed in photoreceptors, revealed depolarization-induced Ca(2+ increments mediated by cacophony. Additional Ca(2+ influx depends on TRP and TRPL, apparently functioning as store-operated channels. Single synaptic boutons resolved in the lamina by FM4-64 fluorescence revealed that vesicle exocytosis depends on cacophony, TRP and TRPL. In the PLC mutant norpA bouton labeling was also impaired, implicating an additional modulation by this enzyme. Internal Ca(2+ also contributes to exocytosis, since this process was reduced after Ca(2+-store depletion. Therefore, several Ca(2+ pathways participate in photoreceptor neurotransmitter release: one is activated by depolarization and involves cacophony; this is complemented by internal Ca(2+ release and the activation of TRP and TRPL coupled to Ca(2+ depletion of internal reservoirs. PLC may regulate the last two processes. TRP and TRPL would participate in two different functions in distant cellular regions, where they are opened by different mechanisms. This work sheds new light on the mechanism of neurotransmitter release in tonic synapses of non-spiking neurons.

  3. Phosphatidylinositol 3-Kinase Couples Localised Calcium Influx to Activation of Akt in Central Nerve Terminals.

    Science.gov (United States)

    Nicholson-Fish, Jessica C; Cousin, Michael A; Smillie, Karen J

    2016-03-01

    The efficient retrieval of synaptic vesicle membrane and cargo in central nerve terminals is dependent on the efficient recruitment of a series of endocytosis modes by different patterns of neuronal activity. During intense neuronal activity the dominant endocytosis mode is activity-dependent endocytosis (ADBE). Triggering of ADBE is linked to calcineurin-mediated dynamin I dephosphorylation since the same stimulation intensities trigger both. Dynamin I dephosphorylation is maximised by a simultaneous inhibition of its kinase glycogen synthase kinase 3 (GSK3) by the protein kinase Akt, however it is unknown how increased neuronal activity is transduced into Akt activation. To address this question we determined how the activity-dependent increases in intracellular free calcium ([Ca(2+)]i) control activation of Akt. This was achieved using either trains of high frequency action potentials to evoke localised [Ca(2+)]i increases at active zones, or a calcium ionophore to raise [Ca(2+)]i uniformly across the nerve terminal. Through the use of either non-specific calcium channel antagonists or intracellular calcium chelators we found that Akt phosphorylation (and subsequent GSK3 phosphorylation) was dependent on localised [Ca(2+)]i increases at the active zone. In an attempt to determine mechanism, we antagonised either phosphatidylinositol 3-kinase (PI3K) or calmodulin. Activity-dependent phosphorylation of both Akt and GSK3 was arrested on inhibition of PI3K, but not calmodulin. Thus localised calcium influx in central nerve terminals activates PI3K via an unknown calcium sensor to trigger the activity-dependent phosphorylation of Akt and GSK3.

  4. Calcium influx through L-type channels attenuates skeletal muscle contraction via inhibition of adenylyl cyclases.

    Science.gov (United States)

    Menezes-Rodrigues, Francisco Sandro; Pires-Oliveira, Marcelo; Duarte, Thiago; Paredes-Gamero, Edgar Julian; Chiavegatti, Tiago; Godinho, Rosely Oliveira

    2013-11-15

    Skeletal muscle contraction is triggered by acetylcholine induced release of Ca(2+) from sarcoplasmic reticulum. Although this signaling pathway is independent of extracellular Ca(2+), L-type voltage-gated calcium channel (Cav) blockers have inotropic effects on frog skeletal muscles which occur by an unknown mechanism. Taking into account that skeletal muscle fiber expresses Ca(+2)-sensitive adenylyl cyclase (AC) isoforms and that cAMP is able to increase skeletal muscle contraction force, we investigated the role of Ca(2+) influx on mouse skeletal muscle contraction and the putative crosstalk between extracellular Ca(2+) and intracellular cAMP signaling pathways. The effects of Cav blockers (verapamil and nifedipine) and extracellular Ca(2+) chelator EGTA were evaluated on isometric contractility of mouse diaphragm muscle under direct electrical stimulus (supramaximal voltage, 2 ms, 0.1 Hz). Production of cAMP was evaluated by radiometric assay while Ca(2+) transients were assessed by confocal microscopy using L6 cells loaded with fluo-4/AM. Ca(2+) channel blockers verapamil and nifedipine had positive inotropic effect, which was mimicked by removal of extracellular Ca(+2) with EGTA or Ca(2+)-free Tyrode. While phosphodiesterase inhibitor IBMX potentiates verapamil positive inotropic effect, it was abolished by AC inhibitors SQ22536 and NYK80. Finally, the inotropic effect of verapamil was associated with increased intracellular cAMP content and mobilization of intracellular Ca(2+), indicating that positive inotropic effects of Ca(2+) blockers depend on cAMP formation. Together, our results show that extracellular Ca(2+) modulates skeletal muscle contraction, through inhibition of Ca(2+)-sensitive AC. The cross-talk between extracellular calcium and cAMP-dependent signaling pathways appears to regulate the extent of skeletal muscle contraction responses.

  5. The Affine q-Schur algebra

    OpenAIRE

    Green, R. M.

    1997-01-01

    We introduce an analogue of the $q$-Schur algebra associated to Coxeter systems of type $\\hat A_{n-1}$. We give two constructions of this algebra. The first construction realizes the algebra as a certain endomorphism algebra arising from an affine Hecke algebra of type $\\hat A_{r-1}$, where $n \\geq r$. This generalizes the original $q$-Schur algebra as defined by Dipper and James, and the new algebra contains the ordinary $q$-Schur algebra and the affine Hecke algebra as subalgebras. Using th...

  6. Affine Projection Algorithm Using Regressive Estimated Error

    OpenAIRE

    Zhang, Shu; Zhi, Yongfeng

    2011-01-01

    An affine projection algorithm using regressive estimated error (APA-REE) is presented in this paper. By redefining the iterated error of the affine projection algorithm (APA), a new algorithm is obtained, and it improves the adaptive filtering convergence rate. We analyze the iterated error signal and the stability for the APA-REE algorithm. The steady-state weights of the APA-REE algorithm are proved to be unbiased and consist. The simulation results show that the proposed algorithm has a f...

  7. Control and estimation of piecewise affine systems

    CERN Document Server

    Xu, Jun

    2014-01-01

    As a powerful tool to study nonlinear systems and hybrid systems, piecewise affine (PWA) systems have been widely applied to mechanical systems. Control and Estimation of Piecewise Affine Systems presents several research findings relating to the control and estimation of PWA systems in one unified view. Chapters in this title discuss stability results of PWA systems, using piecewise quadratic Lyapunov functions and piecewise homogeneous polynomial Lyapunov functions. Explicit necessary and sufficient conditions for the controllability and reachability of a class of PWA systems are

  8. Affine Invariant Character Recognition by Progressive Removing

    Science.gov (United States)

    Iwamura, Masakazu; Horimatsu, Akira; Niwa, Ryo; Kise, Koichi; Uchida, Seiichi; Omachi, Shinichiro

    Recognizing characters in scene images suffering from perspective distortion is a challenge. Although there are some methods to overcome this difficulty, they are time-consuming. In this paper, we propose a set of affine invariant features and a new recognition scheme called “progressive removing” that can help reduce the processing time. Progressive removing gradually removes less feasible categories and skew angles by using multiple classifiers. We observed that progressive removing and the use of the affine invariant features reduced the processing time by about 60% in comparison to a trivial one without decreasing the recognition rate.

  9. Adsorption affinity of anions on metal oxyhydroxides

    Science.gov (United States)

    Pechenyuk, S. I.; Semushina, Yu. P.; Kuz'mich, L. F.

    2013-03-01

    The dependences of anion (phosphate, carbonate, sulfate, chromate, oxalate, tartrate, and citrate) adsorption affinity anions from geometric characteristics, acid-base properties, and complex forming ability are generalized. It is shown that adsorption depends on the nature of both the anions and the ionic medium and adsorbent. It is established that anions are generally grouped into the following series of adsorption affinity reduction: PO{4/3-}, CO{3/2-} > C2O{4/2-}, C(OH)(CH2)2(COO){3/3-}, (CHOH)2(COO){2/2-} > CrO{4/2-} ≫ SO{4/2-}.

  10. Periodic cyclic homology of affine Hecke algebras

    CERN Document Server

    Solleveld, Maarten

    2009-01-01

    This is the author's PhD-thesis, which was written in 2006. The version posted here is identical to the printed one. Instead of an abstract, the short list of contents: Preface 5 1 Introduction 9 2 K-theory and cyclic type homology theories 13 3 Affine Hecke algebras 61 4 Reductive p-adic groups 103 5 Parameter deformations in affine Hecke algebras 129 6 Examples and calculations 169 A Crossed products 223 Bibliography 227 Index 237 Samenvatting 245 Curriculum vitae 253

  11. Crossing Chris: Some Markerian Affinities

    Directory of Open Access Journals (Sweden)

    Adrian Martin

    2010-01-01

    -pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

    Abstract (E: This essay creatively explores a group of artists, writers, and other special individuals whose work or life story can be described as having an intriguing affinity with the protean career of Chris Marker. Avoiding the ‘usual suspects’ (such as Godard or Sebald, it discusses gossip columnist Milt Machlin, record collector Harry Smith, painter Gianfranco Baruchello, writer-filmmaker Edgardo Cozarinsky, and several others. From this constellation, a particular view of Markerian poetics emerges, touching upon the meanings of anonymity, storytelling, history and archiving.

     

    Abstract (F: Cet essai brosse de manière créative le portrait d’un groupe d'artistes, d'écrivains et d'autres personnes particulières dont le travail ou la biographie peuvent être décrits comme montrant une étrange mais certaine connivence avec la carrière protéiforme de Chris Marker. Evitant les lieux communs (comme Godard ou Sebald, cet article trace des références moins attendues :

  12. Blockade of CCR2 reduces macrophage influx and development of chronic renal damage in murine renovascular hypertension.

    Science.gov (United States)

    Kashyap, Sonu; Warner, Gina M; Hartono, Stella P; Boyilla, Rajendra; Knudsen, Bruce E; Zubair, Adeel S; Lien, Karen; Nath, Karl A; Textor, Stephen C; Lerman, Lilach O; Grande, Joseph P

    2016-03-01

    Renovascular hypertension (RVH) is a common cause of both cardiovascular and renal morbidity and mortality. In renal artery stenosis (RAS), atrophy in the stenotic kidney is associated with an influx of macrophages and other mononuclear cells. We tested the hypothesis that chemokine receptor 2 (CCR2) inhibition would reduce chronic renal injury by reducing macrophage influx in the stenotic kidney of mice with RAS. We employed a well-established murine model of RVH to define the relationship between macrophage infiltration and development of renal atrophy in the stenotic kidney. To determine the role of chemokine ligand 2 (CCL2)/CCR2 signaling in the development of renal atrophy, mice were treated with the CCR2 inhibitor RS-102895 at the time of RAS surgery and followed for 4 wk. Renal tubular epithelial cells expressed CCL2 by 3 days following surgery, a time at which no significant light microscopic alterations, including interstitial inflammation, were identified. Macrophage influx increased with time following surgery. At 4 wk, the development of severe renal atrophy was accompanied by an influx of inducible nitric oxide synthase (iNOS)+ and CD206+ macrophages that coexpressed F4/80, with a modest increase in macrophages coexpressing arginase 1 and F4/80. The CCR2 inhibitor RS-102895 attenuated renal atrophy and significantly reduced the number of dual-stained F4/80+ iNOS+ and F4/80+ CD206+ but not F4/80+ arginase 1+ macrophages. CCR2 inhibition reduces iNOS+ and CD206+ macrophage accumulation that coexpress F4/80 and renal atrophy in experimental renal artery stenosis. CCR2 blockade may provide a novel therapeutic approach to humans with RVH.

  13. TRPV3 channels mediate Ca²⁺ influx induced by 2-APB in mouse eggs.

    Science.gov (United States)

    Lee, Hoi Chang; Yoon, Sook-Young; Lykke-Hartmann, Karin; Fissore, Rafael A; Carvacho, Ingrid

    2016-01-01

    Fertilization in mammals is initiated when a sperm fuses with a mature MII oocyte, also known as egg, and triggers a plethora of finely controlled processes identified as egg activation. The completion of all events of egg activation is driven by and depends on a series of repetitive calcium (Ca(2+)) increases (Ca(2+) oscillations), which rely on Ca(2+) influx from the extracellular media. Ca(2+) channels on the egg plasma membrane (PM) are thought to mediate this influx. The TRP Ca(2+) channel TRPV3 is differentially expressed during oocyte maturation, being most active at the MII stage. Specific stimulation of TRPV3 channels promotes Ca(2+) influx sufficient to induce egg activation and parthenogenesis. Here, we explore the function and distribution dynamics of the TRPV3 channel protein during maturation. Using dsRNA, TrpV3 overexpression, and inhibitors of protein synthesis, we modified the expression levels of the channel and showed that the TRPV3 protein is synthesized and translocated to the PM during maturation. We demonstrated that 2-APB at the concentrations used here to promote Ca(2+) influx in eggs, specifically and reversibly targets TRPV3 channels without blocking IP3R1. Finally, we found that the activity of TRPV3 channels is dependent upon an intact actin cytoskeleton, suggesting an actin-based regulation of its expression and/or function on the PM. Collectively, our results show TRPV3 is a target of 2-APB in eggs, a condition that can be used to induce parthenogenesis. The need of an intact actin cytoskeleton for the function of TRPV3 channels in oocytes is a novel finding and suggests the rearrangements of actin that occur during maturation could regulate both the presence on the PM and/or the function of TRPV3 and of other Ca(2+) channels involved in oocyte maturation and fertilization. PMID:26725171

  14. Inhibition of Calcium Influx Reduces Dysfunction and Apoptosis in Lipotoxic Pancreatic β-Cells via Regulation of Endoplasmic Reticulum Stress.

    Directory of Open Access Journals (Sweden)

    Yuren Zhou

    Full Text Available Lipotoxicity plays an important role in pancreatic β-cell failure during the development of type 2 diabetes. Prolonged exposure of β-cells to elevated free fatty acids level could cause deterioration of β-cell function and induce cell apoptosis. Therefore, inhibition of fatty acids-induced β-cell dysfunction and apoptosis might provide benefit for the therapy of type 2 diabetes. The present study examined whether regulation of fatty acids-triggered calcium influx could protect pancreatic β-cells from lipotoxicity. Two small molecule compounds, L-type calcium channel blocker nifedipine and potassium channel activator diazoxide were used to inhibit palmitic acid-induced calcium influx. And whether the compounds could reduce palmitic acid-induced β-cell failure and the underlying mechanism were also investigated. It was found that both nifedipine and diazoxide protected MIN6 pancreatic β-cells and primary cultured murine islets from palmitic acid-induced apoptosis. Meanwhile, the impaired insulin secretion was also recovered to varying degrees by these two compounds. Our results verified that nifedipine and diazoxide could reduce palmitic acid-induced endoplasmic reticulum stress to generate protective effects on pancreatic β-cells. More importantly, it suggested that regulation of calcium influx by small molecule compounds might provide benefits for the prevention and therapy of type 2 diabetes.

  15. Inhibition of ATP-induced calcium influx in HT4 cells by glucocorticoids: involvement of protein kinase A

    Institute of Scientific and Technical Information of China (English)

    Jian-zhong HAN; Wen LIN; Yi-zhang CHEN

    2005-01-01

    Aim: In our previous observations, adenosine triphosphate (ATP) was found to evoke immediate elevations in intracellular free calcium concentration ([Ca2+]i) in HT4 neuroblastoma cells of mice. We tried to see if a brief pretreatment of glucocorticoids could inhibit the Ca2+ response and reveal the underlying signal ing mechanism. Methods: Measurement of [Ca2+]i was carried out using the dual-wavelength fluorescence method with Fura-2 as the indicator. Results: Pre incubation of HT4 cells for 5 min with corticosterone (B) or bovine serum albumin conjugated corticosterone (B-BSA) inhibited the peak [Ca2+]i increments in a concentration-dependent manner. Cortisol and dexamethasone had a similar action, while deoxycorticosterone and cholesterol were ineffective. Both extracellular Ca2+ influx and internal Ca2+ release contributed to ATP-induced [Ca2+]i elevation. The brief treatment with only B attenuated Ca2+ influx. Furthermore, the [Ca2+]i elevation induced by the P2X receptor agonist adenosine 5'-(β,γ-methylene) triphosphate (β,γ-meATP) was also suppressed. The rapid inhibitory effect of B can be reproduced by forskolin 1 mmol/L and blocked by H89 20 mmol/L. Neither nuclear glucocorticoid receptor antagonist mifepristone nor protein kinase C in hibitors influenced the rapid action of B. Conclusion: Our results suggest that glucocorticoids modulate P2X receptor-medicated Ca2+ influx through a membrane-initiated, non-genomic and PKA-dependent pathway in HT4 cells.

  16. Fan Affinity Laws from a Collision Model

    Science.gov (United States)

    Bhattacharjee, Shayak

    2012-01-01

    The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour…

  17. Classification of neocortical interneurons using affinity propagation

    Directory of Open Access Journals (Sweden)

    Roberto eSantana

    2013-12-01

    Full Text Available In spite of over a century of research on cortical circuits, it is still unknown how many classes of cortical neurons exist. Neuronal classification has been a difficult problem because it is unclear what a neuronal cell class actually is and what are the best characteristics are to define them. Recently, unsupervised classifications using cluster analysis based on morphological, physiological or molecular characteristics, when applied to selected datasets, have provided quantitative and unbiased identification of distinct neuronal subtypes. However, better and more robust classification methods are needed for increasingly complex and larger datasets. We explored the use of affinity propagation, a recently developed unsupervised classification algorithm imported from machine learning, which gives a representative example or exemplar for each cluster. As a case study, we applied affinity propagation to a test dataset of 337 interneurons belonging to four subtypes, previously identified based on morphological and physiological characteristics. We found that affinity propagation correctly classified most of the neurons in a blind, non-supervised manner. In fact, using a combined anatomical/physiological dataset, our algorithm differentiated parvalbumin from somatostatin interneurons in 49 out of 50 cases. Affinity propagation could therefore be used in future studies to validly classify neurons, as a first step to help reverse engineer neural circuits.

  18. A 2,4-dichlorophenoxyacetic acid analog screened using a maize coleoptile system potentially inhibits indole-3-acetic acid influx in Arabidopsis thaliana

    OpenAIRE

    Suzuki, Hiromi; Matano, Naoyuki; Nishimura, Takeshi; Koshiba, Tomokazu

    2014-01-01

    Studies using inhibitors of indole-3-acetic acid (IAA) transport, not only for efflux but influx carriers, provide many aspects of auxin physiology in plants. 1-Naphtoxyacetic acid (1-NOA), an analog of the synthetic auxin 1-N-naphtalene acetic acid (NAA), inhibits the IAA influx carrier AUX1. However, 1-NOA also shows auxin activity because of its structural similarity to NAA. In this study, we have identified another candidate inhibitor of the IAA influx carrier. The compound, “7-B3; ethyl ...

  19. A comparison of methods to determine locations and magnitudes of groundwater influx to rivers

    Science.gov (United States)

    Briggs, Martin A.; Lautz, Laura K.; McKenzie, Jeffrey M.

    2010-05-01

    There are currently several methods available for determining both the spatial distribution and magnitude of groundwater inputs to rivers and streams. Methods range from physical flow gauging to introduced and natural tracers, all of which have varied levels of resolution and suitability to specific system conditions. We compared the results of tracer analyses (using fluorescent dye, heat, and geochemical end-members) to physical flow measurements along 900 m of Ninemile Creek in Syracuse, New York, USA during summer low-flow conditions (discharge = 1.4 m3/s). Temperature measurements were made using an Agilent Distributed Temperature Sensor (DTS) which recorded temperature at 1.5 m increments over the length of a fiber optic cable installed along the thalweg at the sediment-water interface. The 24 hr mean and standard deviation of these measurements indicated one region of focused groundwater input to the river of ~ 0.07 m3/s. A constant rate injection of Rhodamine WT dye also identified an influx of groundwater over the same region of ~ 0.07 m3/s. Geochemical samples were collected every 50 m along the reach, and the groundwater end-member, which is highly saline, was sampled from shallow piezometers installed in the stream bed and bank. End-member mixing models between stream and groundwater using calcium and chloride also generated estimated gains of ~ 0.07 m3/s over the same reach location. In contrast to these results, physical flow measurements made approximately every 100 m using a handheld FlowTracker acoustic Doppler velocimeter failed to identify, much less quantify, the focused groundwater input. The failure of the physical flow measurements was attributed to the high variability in discharge estimates, which had a standard deviation of 0.13 m3/s. The measurement variability likely resulted from stream turbulence due to high velocities, extensive macrophyte growth and non-ideal channel bedform. These results indicate that the use of natural tracers such

  20. Tests of Transport Theory and Reduced Impurity Influx with Highly Radiative Plasmas in TFTR

    Science.gov (United States)

    Hill, K. W.

    1997-11-01

    ,(M. Kotschenreuther, W. Dorland, M. A. Beer, and G. W. Hammett, Phys. Plasmas 2, 2381 (1995)) which has strong marginal-stability behavior, are reasonable; more detailed comparisons are in progress. Use of high-Z radiators did not impair fusion performance, confirming they can be used to reduce the heat flux to the plasma facing components with minimal ion dilution. At input power level s of 30-33 MW, enhanced radiation through krypton and xenon puffing eliminated serious carbon influx (carbon ``blooms") which occurred in comparable plasmas without impurity puffing.

  1. Congophilicity (Congo red affinity) of different beta2-microglobulin conformations characterized by dye affinity capillary electrophoresis

    DEFF Research Database (Denmark)

    Heegaard, N H; Sen, J W; Nissen, Mogens Holst

    2000-01-01

    The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red-affinities of......The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red......-affinities of native and abnormally folded beta2-microglobulin. We find that native beta2-microglobulin has an intermediate affinity for Congo red at pH 7.3 and that binding involves electrostatic interactions. The conformational variant of beta2-microglobulin that appears in acetonitrile solutions binds Congo red...... more strongly. Affinity CE using Congo red as a buffer additive is a new, simple, fast, and quantitative micromethod for the characterization of soluble conformational intermediates of amyloidogenic proteins....

  2. Influence of river influx on phytoplankton community during fall inter–monsoon in the coastal waters off Kakinada, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sooria, P.M.; Reny, P.D.; Jagadeesan, L.; Nair, M.

    Significant changes in phytoplankton community structure were observed in the coastal waters off Kakinada, India during fall inter-monsoon of 2006 and 2007. River influx was more in October 2007 compared to those in October 2006. Phytoplankton...

  3. Ca2+ influx and efflux in animal cells in the presence of panax notoginseng extracts: investigated by using 45Ca as a radioactive tracer

    International Nuclear Information System (INIS)

    In this paper, the influence of extracts of Panax notoginseng on Ca2+ influx and efflux in isolated rat visceral organs was investigated by using 45Ca as a radioactive tracer. The results indicated that both extracts, the total flavonoids and total saponins of Panax notoginseng had significant influence on Ca2+ influx and efflux in the isolated rat aorta, heart, and kidney, in those organs it could markedly block 45Ca entering into cell and could facilitate efflux of intracellular Ca2+. Compared with the total flavonoids, total saponins had stronger role in the regulation of Ca2+ influx and efflux. Also, regulation effects of Ca2+ influx and efflux of the total saponins were compared with positive drug Verapamil, or even better. This implies that the total flavonoids and total saponins of Panax notoginseng have calcium antagonistic effect, and both may be the active ingredients in Panax notoginseng for coronary heart disease treatment. (authors)

  4. From blue to black: Anthropogenic forcing of carbon and nitrogen influx to mangrove-lined estuaries in the South China Sea.

    Science.gov (United States)

    Lee, S Y

    2016-08-30

    Southeast Asia is the global centre of mangrove development but human activities have dramatically reduced mangrove area in the region. An analysis is made of the shift in carbon and nitrogen influxes into the South China Sea (SCS) resulting from three anthropogenic nutrient sources: domestic sewage discharge, fertilizer use in rice agriculture and environmental loss from mariculture, between 1997 and 2010. Anthropogenic C and N influxes were, respectively, 1.81× and 1.43× those in 1997, with coastal aquaculture contributing most to the increase. In contrast, fringing mangroves provided ~44% of the C but only ~3% of the N from anthropogenic sources in 2010. In 1997, influx from mangroves was 113% and 6% of anthropogenic influx for C and N, respectively. This dominance by relatively labile anthropogenic nutrients over mangrove sources would change nearshore trophodynamics, with negative implications for the resilience of mangroves and nutrient-intolerant systems such as corals. PMID:26781456

  5. Improved native affinity purification of RNA.

    Science.gov (United States)

    Batey, Robert T; Kieft, Jeffrey S

    2007-08-01

    RNA biochemical or structural studies often require an RNA sample that is chemically pure, and most protocols for its in vitro production use denaturing polyacrylamide gel electrophoresis to achieve this. Unfortunately, many RNAs do not quantitatively refold into an active conformation after denaturation, creating significant problems for downstream characterization or use. In addition, this traditional purification method is not amenable to studies demanding high-throughput RNA production. Recently, we presented the first general method for producing almost any RNA sequence that employs an affinity tag that is removed during the purification process. Because technical difficulties prevented application of this method to many RNAs, we have developed an improved version that utilizes a different activatable ribozyme and affinity tag that are considerably more robust, rapid, and broadly applicable. PMID:17548432

  6. AFFINITY OF LIGNIN PREPARATIONS TOWARDS GENOTOXIC COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Božena Košíková

    2009-02-01

    Full Text Available The carcinogenicity and mutagenicity of chemicals may be modulated by other chemicals, including those prepared by organic synthesis. Consid-ering the several drawbacks of synthetic compounds vis-a-vis the human organism, the lignin biomass component was examined for this purpose. The binding affinity of lignin samples prepared by chemical and biological modification of lignin products derived from chemical wood treatment towards for N-nitrosodiethylamine (NDA was examined. The protective role of the lignin samples against carcinogenesis was tested on a well-known model carcinogen, N-methyl-N´-nitro-N-nitrosoguanidine (MNNG. The observed ability of a series of lignin preparations to reduce alkylation damage of deoxyribonucleic acid (DNA on hamster cells in vitro could be explained by their affinity to bind N-nitrosoamines. The results indicate that lignin has potential to protect living organisms against damaging effects of different genotoxicants.

  7. Local structure of self-affine sets

    CERN Document Server

    Bandt, Christoph

    2011-01-01

    The structure of a self-similar set with open set condition does not change under magnification. For self-affine sets the situation is completely different. We consider planar self-affine Cantor sets E of the type studied by Bedford, McMullen, Gatzouras and Lalley, for which the projection onto the horizontal axis is an interval. We show that within small square neighborhoods of almost each point x in E, with respect to many product measures on address space, E is well approximated by product sets of an interval and a Cantor set. Even though E is totally disconnected, the limit sets have the product structure with interval fibres, reminiscent to the view of attractors of chaotic differentiable dynamical systems.

  8. Recent Results Regarding Affine Quantum Gravity

    CERN Document Server

    Klauder, John R

    2012-01-01

    Recent progress in the quantization of nonrenormalizable scalar fields has found that a suitable non-classical modification of the ground state wave function leads to a result that eliminates term-by-term divergences that arise in a conventional perturbation analysis. After a brief review of both the scalar field story and the affine quantum gravity program, examination of the procedures used in the latter surprisingly shows an analogous formulation which already implies that affine quantum gravity is not plagued by divergences that arise in a standard perturbation study. Additionally, guided by the projection operator method to deal with quantum constraints, trial reproducing kernels are introduced that satisfy the diffeomorphism constraints. Furthermore, it is argued that the trial reproducing kernels for the diffeomorphism constraints may also satisfy the Hamiltonian constraint as well.

  9. Thermodynamics. Using Affinities to define reversible processes

    CERN Document Server

    Ritacco, Hernán A

    2016-01-01

    In this article a definition of reversible processes in terms of differences in intensive Thermodynamics properties (Affinities) is proposed. This definition makes it possible to both define reversible processes before introducing the concept of entropy and avoid the circularity problem that follows from the Clausius definition of entropy changes. The convenience of this new definition compared to those commonly found in textbooks is demonstrated with examples.

  10. AFFINE TRANSFORMATION IN RANDOM ITERATED FUNCTION SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    熊勇; 史定华

    2001-01-01

    Random iterated function systems (IFSs) is discussed, which is one of the methods for fractal drawing. A certain figure can be reconstructed by a random IFS. One approach is presented to determine a new random IFS, that the figure reconstructed by the new random IFS is the image of the origin figure reconstructed by old IFS under a given affine transformation. Two particular examples are used to show this approach.

  11. A MEMS Dielectric Affinity Glucose Biosensor.

    Science.gov (United States)

    Huang, Xian; Li, Siqi; Davis, Erin; Li, Dachao; Wang, Qian; Lin, Qiao

    2013-06-20

    Continuous glucose monitoring (CGM) sensors based on affinity detection are desirable for long-term and stable glucose management. However, most affinity sensors contain mechanical moving structures and complex design in sensor actuation and signal readout, limiting their reliability in subcutaneously implantable glucose detection. We have previously demonstrated a proof-of-concept dielectric glucose sensor that measured pre-mixed glucose-sensitive polymer solutions at various glucose concentrations. This sensor features simplicity in sensor design, and possesses high specificity and accuracy in glucose detection. However, lack of glucose diffusion passage, this device is unable to fulfill real-time in-vivo monitoring. As a major improvement to this device, we present in this paper a fully implantable MEMS dielectric affinity glucose biosensor that contains a perforated electrode embedded in a suspended diaphragm. This capacitive-based sensor contains no moving parts, and enables glucose diffusion and real-time monitoring. The experimental results indicate that this sensor can detect glucose solutions at physiological concentrations and possesses good reversibility and reliability. This sensor has a time constant to glucose concentration change at approximately 3 min, which is comparable to commercial systems. The sensor has potential applications in fully implantable CGM that require excellent long-term stability and reliability. PMID:24511215

  12. Overview of affinity biosensors in food analysis.

    Science.gov (United States)

    Patel, Pradip D

    2006-01-01

    The 4 major driving forces that are expected to lead to increased use of affinity biosensors that meet crucial industrial test specifications, e.g., fast, reliable, cost-effective, and use of low-skilled personnel, are (1) strict legislative framework, e.g., recent changes proposed to the European food safety and hygiene legislation, EC No. 178/2002; (2) industrial shift from quality control to quality assurance procedures, e.g., Hazard Analysis Critical Control Point, ensuring effective positioning in the global competitive trade; (3) just-in-time production resulting in 'right' product every time; and (4) consumer demand for safe and wholesome products. The affinity biosensors field has expanded significantly over the past decade, with a projected global biosensors market growth from $6.1 billion in 2004 to $8.2 billion in 2009, representing major industrial sectors (e.g., Pharma, Medicare, and Food). This brief review is targeted to affinity biosensors developed for the food industry and includes research and development leading to biosensors for microbiological and chemical analytes of industrial concern, commercial biosensors products on the market, and examples of future prospects in this diagnostic field. PMID:16792079

  13. Overview of affinity biosensors in food analysis.

    Science.gov (United States)

    Patel, Pradip D

    2006-01-01

    The 4 major driving forces that are expected to lead to increased use of affinity biosensors that meet crucial industrial test specifications, e.g., fast, reliable, cost-effective, and use of low-skilled personnel, are (1) strict legislative framework, e.g., recent changes proposed to the European food safety and hygiene legislation, EC No. 178/2002; (2) industrial shift from quality control to quality assurance procedures, e.g., Hazard Analysis Critical Control Point, ensuring effective positioning in the global competitive trade; (3) just-in-time production resulting in 'right' product every time; and (4) consumer demand for safe and wholesome products. The affinity biosensors field has expanded significantly over the past decade, with a projected global biosensors market growth from $6.1 billion in 2004 to $8.2 billion in 2009, representing major industrial sectors (e.g., Pharma, Medicare, and Food). This brief review is targeted to affinity biosensors developed for the food industry and includes research and development leading to biosensors for microbiological and chemical analytes of industrial concern, commercial biosensors products on the market, and examples of future prospects in this diagnostic field.

  14. On constructing purely affine theories with matter

    CERN Document Server

    Cervantes-Cota, Jorge L

    2016-01-01

    We explore ways to obtain the very existence of a space-time metric from an action principle that does not refer to it a priori. Although there are reasons to believe that only a non-local theory can viably achieve this goal, we investigate here local theories that start with Schroedinger's purely affine theory [21], where he gave reasons to set the metric proportional to the Ricci curvature aposteriori. When we leave the context of unified field theory, and we couple the non-gravitational matter using some weak equivalence principle, we can show that the propagation of shock waves does not define a lightcone when the purely affine theory is local and avoids the explicit use of the Ricci tensor in realizing the weak equivalence principle. When the Ricci tensor is substituted for the metric, the equations seem to have only a very limited set of solutions. This backs the conviction that viable purely affine theories have to be non-local.

  15. On constructing purely affine theories with matter

    Science.gov (United States)

    Cervantes-Cota, Jorge L.; Liebscher, D.-E.

    2016-08-01

    We explore ways to obtain the very existence of a space-time metric from an action principle that does not refer to it a priori. Although there are reasons to believe that only a non-local theory can viably achieve this goal, we investigate here local theories that start with Schrödinger's purely affine theory (Schrödinger in Space-time structure. Cambridge UP, Cambridge, 1950), where he gave reasons to set the metric proportional to the Ricci curvature aposteriori. When we leave the context of unified field theory, and we couple the non-gravitational matter using some weak equivalence principle, we can show that the propagation of shock waves does not define a lightcone when the purely affine theory is local and avoids the explicit use of the Ricci tensor in realizing the weak equivalence principle. When the Ricci tensor is substituted for the metric, the equations seem to have only a very limited set of solutions. This backs the conviction that viable purely affine theories have to be non-local.

  16. Geochemical provenance of soils in Kerman urban areas, Iran: Implications for the influx of aeolian dust

    Science.gov (United States)

    Dehbandi, Reza; Aftabi, Alijan

    2016-06-01

    The investigation of the interaction of aeolian dust with residual soils has not been fully explored in the Kerman urban areas, Iran. To assess the geochemical influence of aeolian dust on the residual soils of the Kerman urban areas of Iran, 27 samples were studied petrogeochemically. The arid-semi-arid climate of the area together with the southwest-northeast prevailing wind, have deposited aeolian sands over the residual soils. Residual soils reflect similar mineral compositions to that of the underlying bedrock and include mostly calcite and quartz. However, the minor occurrences of pyroxene, amphibole, olivine, plagioclase and volcanic clasts in urban soils and aeolian dust are attributed to volcanogenic inputs transported by aeolian dust. Urban soils and aeolian dust show different geochemical signatures from the local carbonate rocks. All samples contain trace element concentrations that are higher than the carbonate bedrock. Discrimination diagrams indicate that immobile trace elements have geochemical affinity to the detrital ferromagnesian dust inputs and are different from the local carbonate bedrock. Based on the elemental bivariate and ternary diagrams, the soils and aeolian dust are derived from the interaction of carbonate and volcanic rocks. This highlights that the urban soils in the Kerman urban areas have been formed by interactions of the aeolian dust with the primitive residual soils.

  17. Functional and fluorochrome analysis of an exocytotic mutant yields evidence of store-operated Ca2+ influx in Paramecium.

    Science.gov (United States)

    Mohamed, I; Klauke, N; Hentschel, J; Cohen, J; Plattner, H

    2002-05-01

    A non-discharge mutant of Paramecium tetraurelia (nd12-35 degrees C, lacking exocytotic response upon stimulation with the nonpermeable polycationic secretagogue aminoethyldextran, AED), in the pawnA genetic context (d4-500r, lacking ciliary voltage-dependent Ca2+ influx), was shown to lack (45)Ca2+ entry from outside upon AED stimulation. In contrast, cells grown at 25 degrees C behave like the wildtype. To check the functional properties in more detail, fluorochrome-loaded 35 degrees C cells were stimulated, not only with AED (EC(100) = 10(-6) M in wildtype cells), but also with 4-chloro-meta-cresol, (4CmC, 0.5 mM), a permeable activator of ryanodine receptor-type Ca2+ release channels, usually at extracellular [Ca2+] of 50 microM, and eventually with a Ca2+ chelator added. We confirm that pwA-nd12(35 degrees C) cells lack any Ca2+ influx and any exocytosis of trichocysts in response to any stimulus. As we determined by x-ray microanalysis, total calcium content in alveolar sacs (subplasmalemmal stores) known to be mobilized upon exocytosis stimulation in wild-type cells, contain about the same total calcium in 35 degrees C as in 25 degrees C cells, and Ca2+ mobilization from alveoli by AED or 4CmC is also nearly the same. Due to the absence of any AED-induced Ca2+ influx in 35 degrees C cells and normal Ca2+ release from stores found by x-ray microanalysis one can exclude a "CICR"-type mechanism (Ca2+-induced Ca2+ release) and imply that normally a store-operated Ca2+ ("SOC") influx would occur (as in 25 degrees C cells). Furthermore, 35 degrees C cells display a significantly lower basal intracellular [Ca2+], so that any increase upon stimulation may be less expressed or even remain undetected. Under these conditions, any mobilization of Ca2+ from stores cannot compensate for the lack of Ca2+ influx, particularly since normally both components have to cooperate to achieve full exocytotic response. Also striking is our finding that 35 degrees C cells are unable

  18. Antitumor activity of 7-aminocarboxycoumarin derivatives, a new class of potent inhibitors of lactate influx but not efflux.

    Science.gov (United States)

    Draoui, Nihed; Schicke, Olivier; Seront, Emmanuel; Bouzin, Caroline; Sonveaux, Pierre; Riant, Olivier; Feron, Olivier

    2014-06-01

    High lactate concentration in tumors is associated with bad prognosis. Lactate is released by glycolytic cells in tumors and recaptured by oxidative cancer cells to feed the tricarboxylic acid (TCA) cycle after conversion into pyruvate. Monocarboxylate transporters (MCT) mediate these fluxes of proton-linked lactate and represent attractive targets to interrupt lactate shuttle and to inhibit tumor growth. Here, we investigated the properties of 7-aminocarboxycoumarins (7ACC) developed to selectively interfere with lactate fluxes in the lactate-rich tumor microenvironment. The pharmacologic properties of two compounds of this family, including their effects on lactate influx and efflux and antitumor activity, were investigated using human cancer cell lines and mouse xenograft models. Contrary to the reference MCT1 inhibitor AR-C155858, 7ACC unexpectedly inhibited lactate influx but not efflux in tumor cells expressing MCT1 and MCT4 transporters. 7ACC delayed the growth of cervix SiHa tumors, colorectal HCT116 tumors, and orthoptopic MCF-7 breast tumors. MCT target engagement was confirmed by the lack of activity of 7ACC on bladder UM-UC-3 carcinoma that does not express functional MCT. 7ACC also inhibited SiHa tumor relapse after treatment with cisplatin. Finally, we found that contrary to AR-C155858, 7ACC did not prevent the cell entry of the substrate-mimetic drug 3-bromopyruvate (3BP) through MCT1, and contributed to the inhibition of tumor relapse after 3BP treatment. In conclusion, our results indicate that 7ACC selectively affects a single part of the MCT symporter translocation cycle, leading to strict inhibition of lactate influx. This singular activity is associated with antitumor effects less prone to resistance and side effects. PMID:24672058

  19. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    Energy Technology Data Exchange (ETDEWEB)

    Ostrow, Lyle W., E-mail: lostrow1@jhmi.edu [Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205 (United States); Suchyna, Thomas M.; Sachs, Frederick [Department of Physiology and Biophysical Sciences, State University of New York at Buffalo, Buffalo, NY 14214 (United States)

    2011-06-24

    Highlights: {yields} Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. {yields} Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca{sup 2+} permeant SACs. {yields} The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. {yields} Stretch-induced ET-1 production depends on a calcium influx. {yields} SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch (<20%) of a rubber substrate increased ET-1 secretion, and 4 {mu}M GsMTx-4 (a specific inhibitor of SACs) inhibited secretion by 30%. GsMTx-4 did not alter basal ET-1 levels in the absence of stretch. Decreasing the calcium influx by lowering extracellular calcium also inhibited stretch-induced ET-1 secretion without effecting ET-1 secretion in unstretched controls. Furthermore, inhibiting SACs with the less specific inhibitor streptomycin also inhibited stretch-induced ET-1 secretion. The data can be explained with a simple model in which ET-1 secretion depends on an internal Ca{sup 2+} threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  20. Cation transport in oxidant-stressed human erythrocytes: heightened N-ethylmaleimide activation of passive K+ influx after mild peroxidation.

    Science.gov (United States)

    Sheerin, H E; Snyder, L M; Fairbanks, G

    1989-07-24

    Normal and chronically dehydrated (hereditary xerocytosis) human red cells were subjected to mild peroxidative treatment (315 microM hydrogen peroxide (H2O2), 15 min) in the presence of azide. The subsequent expression of passive (ouabain-resistant) K+ transport activities was analyzed by measurement of 86Rb+ influx. Peroxidation of normal red cells did not affect basal K+ transport activity, but the increment in K+ influx elicited by 0.5 mM N-ethylmaleimide (NEM) was increased 3-fold. The enhanced K+ influx was chloride-dependent, but only partially inhibited by 0.1 mM furosemide. Stimulated activity declined progressively after NEM activation, but could be restored by a second NEM treatment. Prior conversion of hemoglobin to the carbonmonoxy form abolished the response to peroxide, while 200 microM butylated hydroxytoluene (BHT) exerted only partial inhibition, suggesting that the effect of H2O2 requires interaction of activated, unstable hemoglobin species with the membrane, but that lipid peroxidation is not sufficient. Peroxidation following NEM treatment also enhanced NEM activation, indicating that enhancement does not require altered NEM reactions with stimulatory or inhibitory sites. Passive K+ transport in hereditary xerocytosis red cells was not activated by NEM, with or without H2O2 pretreatment. The results demonstrate that modest peroxidative damage to red cells can heighten the activation of a transport system that is thought to be capable of mediating net K+ efflux and volume reduction in cells that express it. Models are proposed in which the effects of NEM, H2O2, cell swelling and other factors are mediated by conformational changes in a postulated subpopulation of anion channel (Band 3) molecules that bind the K+ transporter. PMID:2758051

  1. Beta-blockers, left and right ventricular function, and in-vivo calcium influx in muscular dystrophy cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Alison Blain

    Full Text Available Beta-blockers are used to treat acquired heart failure in adults, though their role in early muscular dystrophy cardiomyopathy is unclear. We treated 2 different dystrophic mouse models which have an associated cardiomyopathy (mdx: model for Duchenne Muscular Dystrophy, and Sgcd-/-: model for limb girdle muscular dystrophy type 2F and wild type controls (C57 Bl10 with the beta blocker metoprolol or placebo for 8 weeks at an early stage in the development of the cardiomyopathy. Left and right ventricular function was assessed with cardiac magnetic resonance imaging (MRI and in-vivo myocardial calcium influx with manganese enhanced MRI. In the mdx mice at baseline there was reduced stroke volume, cardiac index, and end-diastolic volume with preserved left ventricular ejection fraction. These abnormalities were no longer evident after treatment with beta-blockers. Right ventricular ejection fraction was reduced and right ventricular end-systolic volume increased in the mdx mice. With metoprolol there was an increase in right ventricular end-diastolic and end-systolic volumes. Left and right ventricular function was normal in the Sgcd-/- mice. Metroprolol had no significant effects on left and right ventricular function in these mice, though heart/body weight ratios increased after treatment. In-vivo myocardial calcium influx with MEMRI was significantly elevated in both models, though metoprolol had no significant effects on either. In conclusion, metoprolol treatment at an early stage in the development of cardiomyopathy has deleterious effects on right ventricular function in mdx mice and in both models no effect on increased in-vivo calcium influx. This suggests that clinical trials need to carefully monitor not just left ventricular function but also right ventricular function and other aspects of myocardial metabolism.

  2. Calcium influx rescues adenylate cyclase-hemolysin from rapid cell membrane removal and enables phagocyte permeabilization by toxin pores.

    Directory of Open Access Journals (Sweden)

    Radovan Fiser

    Full Text Available Bordetella adenylate cyclase toxin-hemolysin (CyaA penetrates the cytoplasmic membrane of phagocytes and employs two distinct conformers to exert its multiple activities. One conformer forms cation-selective pores that permeabilize phagocyte membrane for efflux of cytosolic potassium. The other conformer conducts extracellular calcium ions across cytoplasmic membrane of cells, relocates into lipid rafts, translocates the adenylate cyclase enzyme (AC domain into cells and converts cytosolic ATP to cAMP. We show that the calcium-conducting activity of CyaA controls the path and kinetics of endocytic removal of toxin pores from phagocyte membrane. The enzymatically inactive but calcium-conducting CyaA-AC⁻ toxoid was endocytosed via a clathrin-dependent pathway. In contrast, a doubly mutated (E570K+E581P toxoid, unable to conduct Ca²⁺ into cells, was rapidly internalized by membrane macropinocytosis, unless rescued by Ca²⁺ influx promoted in trans by ionomycin or intact toxoid. Moreover, a fully pore-forming CyaA-ΔAC hemolysin failed to permeabilize phagocytes, unless endocytic removal of its pores from cell membrane was decelerated through Ca²⁺ influx promoted by molecules locked in a Ca²⁺-conducting conformation by the 3D1 antibody. Inhibition of endocytosis also enabled the native B. pertussis-produced CyaA to induce lysis of J774A.1 macrophages at concentrations starting from 100 ng/ml. Hence, by mediating calcium influx into cells, the translocating conformer of CyaA controls the removal of bystander toxin pores from phagocyte membrane. This triggers a positive feedback loop of exacerbated cell permeabilization, where the efflux of cellular potassium yields further decreased toxin pore removal from cell membrane and this further enhances cell permeabilization and potassium efflux.

  3. Experimental investigation of streamer affinity for dielectric surfaces

    NARCIS (Netherlands)

    Trienekens, D.J.M.; Nijdam, S.; Akkermans, G.; Plompen, I.; Christen, T.; Ebert, U.

    2015-01-01

    We have experimentally investigated the affinity of streamers for dielectric surfaces using stroboscopic imaging and stereo photography. Affinity of streamers for dielectric surfaces was found to depend on a wide set of parameters, including pressure, voltage, dielectric material and di

  4. Quelques remarques sur la notion de modification affine

    OpenAIRE

    Dubouloz, Adrien

    2005-01-01

    in french We construct a global counterpart to the notion of affine modification due to Kaliman and Zaidenberg. This leads to a simple explicit description of the structure of birational affine morphisms between arbitrary quasi-projective varieties.

  5. In situ spectral calibration method for the impurity influx monitor (divertor) for ITER using angled physical contact fibers.

    Science.gov (United States)

    Iwamae, A; Ogawa, H; Sugie, T; Kusama, Y

    2011-03-01

    The in situ calibration method for the impurity influx monitor (divertor) is experimentally examined. The total reflectance of the optical path from the focal point of the Cassegrain telescope to the first mirror is derived using a micro retroreflector array. An optical fiber with angled physical contact (APC) connectors reduces the return edge reflection. APC fibers and a multimode coupler increase the signal-to-noise ratio by about one order compared to that of triple-branched fibers and enable measurement of the wavelength dependence of the total reflectance of the optical system even after potential deterioration of mirror surfaces reduces reflectance.

  6. Fractal Homeomorphism for Bi-affine Iterated Function Systems

    CERN Document Server

    Barnsley, Michael

    2011-01-01

    The paper concerns fractal homeomorphism between the attractors of two bi-affine iterated function systems. After a general discussion of bi-affine functions, conditions are provided under which a bi-affine iterated function system is contractive, thus guaranteeing an attractor. After a general discussion of fractal homeomorphism, fractal homeomorphisms are constructed for a specific type of bi-affine iterated function system.

  7. The purification of affinity-labelled active-site peptides

    International Nuclear Information System (INIS)

    The isolation of the labelled peptide from the protein digest, following the affinity labelling of the active sites of enzymes or antibodies, is described. Single-step affinity chromatography utilises the affinity of the native enzymes or antibody for the ligand used to label the same protein. The labelled peptide is the only one in the digest that displays affinity for the immobilised protein and can be released with eluants that dissociate the protein-ligand complex. (Auth.)

  8. Duals of Affine Grassmann Codes and Their Relatives

    DEFF Research Database (Denmark)

    Beelen, P.; Ghorpade, S. R.; Hoholdt, T.

    2012-01-01

    Affine Grassmann codes are a variant of generalized Reed-Muller codes and are closely related to Grassmann codes. These codes were introduced in a recent work by Beelen Here, we consider, more generally, affine Grassmann codes of a given level. We explicitly determine the dual of an affine Grassm...

  9. A cell model study of calcium influx mechanism regulated by calcium-dependent potassium channels in Purkinje cell dendrites.

    Science.gov (United States)

    Chono, Koji; Takagi, Hiroshi; Koyama, Shozo; Suzuki, Hideo; Ito, Etsuro

    2003-10-30

    The present study was designed to elucidate the roles of dendritic voltage-gated K+ channels in Ca2+ influx mechanism of a rat Purkinje cell using a computer simulation program. First, we improved the channel descriptions and the maximum conductance in the Purkinje cell model to mimic both the kinetics of ion channels and the Ca2+ spikes, which had failed in previous studies. Our cell model is, therefore, much more authentic than those in previous studies. Second, synaptic inputs that mimic stimulation of parallel fibers and induce sub-threshold excitability were simultaneously applied to the spiny dendrites. As a result, transient Ca2+ responses were observed in the stimulation points and they decreased with the faster decay rate in the cell model including high-threshold Ca2+-dependent K+ channels than in those excluding these channels. Third, when a single synaptic input was applied into a spiny dendrite, Ca2+-dependent K+ channels suppressed Ca2+ increases at stimulation and recording points. Finally, Ca2+-dependent K+ channels were also found to suppress the time to peak Ca2+ values in the recording points. These results suggest that the opening of Ca2+-dependent K+ channels by Ca2+ influx through voltage-gated Ca2+ channels hyperpolarizes the membrane potentials and deactivates these Ca2+ channels in a negative feedback manner, resulting in local, weak Ca2+ responses in spiny dendrites of Purkinje cells.

  10. Effect of cholera toxin on cAMP levels and Na/sup +/ influx in isolated intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, C.S.; Kimmich, G.A.

    1982-09-01

    Freshly isolated chicken intestinal cells contain approximately 20 pmol adenosine 3',5'-cyclic monophosphate (cAMP)/mg cellular protein. Incubation with 3 ..mu..g/ml cholera toxin (CT) at 37/sup 0/C induces an elevation of cellular cAMP beginning 10-15 min after initial exposure. The response is linear with time for 40-50 min and causes a six- to eightfold increase over control levels at steady state. Dibutyryl cAMP and agents that increase cAMP production inhibit Na/sup +/ influx into the isolated enterocytes. Chlorpromazine completely abolishes the toxin-induced elevation of cAMP in the isolated cells and also reverses the effect on Na/sup +/ entry. The data provide evidence for a cAMP-mediated control of intestinal cell Na/sup +/ uptake, which may represent the mechanistic basis for the antiabsorptive effect of CT on Na/sup +/ during induction of intestinal secretory activity. Studies on the time-dependent effects of chlorpromazine on both intracellular cAMP concentration and Na/sup +/ influx suggest that the reactivation of the Na/sup +/ transport system after cAMP-induced inhibition is slow relative to the disappearance of cAMP.

  11. Salvia miltiorrhiza Induces Tonic Contraction of the Lower Esophageal Sphincter in Rats via Activation of Extracellular Ca2+ Influx

    Directory of Open Access Journals (Sweden)

    Ching-Chung Tsai

    2015-08-01

    Full Text Available Up to 40% of patients with gastroesophageal reflux disease (GERD suffer from proton pump inhibitor refractory GERD but clinically the medications to strengthen the lower esophageal sphincter (LES to avoid irritating reflux are few in number. This study aimed to examine whether Salvia miltiorrhiza (SM extracts induce tonic contraction of rat LES ex vivo and elucidate the underlying mechanisms. To investigate the mechanism underlying the SM extract-induced contractile effects, rats were pretreated with atropine (a muscarinic receptor antagonist, tetrodotoxin (a sodium channel blocker, nifedipine (a calcium channel blocker, and Ca2+-free Krebs-Henseleit solution with ethylene glycol tetraacetic acid (EGTA, followed by administration of cumulative dosages of SM extracts. SM extracts induced dose-related tonic contraction of the LES, which was unaffected by tetrodotoxin, atropine, or nifedipine. However, the SM extract-induced LES contraction was significantly inhibited by Ca2+-free Krebs-Henseleit solution with EGTA. Next, SM extracts significantly induce extracellular Ca2+ entry into primary LES cells in addition to intracellular Ca2+ release and in a dose-response manner. Confocal fluorescence microscopy showed that the SM extracts consistently induced significant extracellular Ca2+ influx into primary LES cells in a time-dependent manner. In conclusion, SM extracts could induce tonic contraction of LES mainly through the extracellular Ca2+ influx pathway.

  12. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    International Nuclear Information System (INIS)

    Highlights: → Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. → Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca2+ permeant SACs. → The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. → Stretch-induced ET-1 production depends on a calcium influx. → SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch (2+ threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  13. The Role of Extracellular Ca2+ Influx,Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    SunQing-yuan; TanJing-he; 等

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied.Ca2+ chelator,ethylen glycol-bis-(2-aminoethyl)-tetracetic acid(EGTA),and calmodulin(CaM) antagonist,trifluoperzaine (TFP),inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verspamil,did not have any effect.When intracellular Ca2+ release was blocked by 8-(N,N-diethylamino) octy 1-3,4,5-trimethoxy-benzonate(TME-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-At-Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased.In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization.The results sugest that both extracellular influx,intracellular Ca2+ release and CaM activation are required for mormal fertilization.However,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 and not the only pathways for producing Ca2+ transients in moue eggs.

  14. The Role of Extracellular Ca2+Influx, Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied. Ca2+ chelator, ethylen glycol-bis-(2-aminoethyl)-tetracetic acid (EGTA) ,and calmodulin (CaM) antagonist,trifluoperzaine (TFP) ,inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verapamil ,did not have any effect. When intracellular Ca2+ release was blocked by 8-(N, N-diethylamino) octy1-3,4,5-trimethoxy- benzonate (TMB-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-AT- Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased. In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization. The results sugest that both extracellular influx,intracellu- lar Ca2+ release and CaM activation are required for normal fertilization. However ,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 are not the only pathways for producing Ca2+ transients in moue eggs.

  15. Mechanisms of calcium influx into hippocampal spines: heterogeneity among spines, coincidence detection by NMDA receptors, and optical quantal analysis.

    Science.gov (United States)

    Yuste, R; Majewska, A; Cash, S S; Denk, W

    1999-03-15

    Dendritic spines receive most excitatory inputs in the vertebrate brain, but their function is still poorly understood. Using two-photon calcium imaging of CA1 pyramidal neurons in rat hippocampal slices, we investigated the mechanisms by which calcium enters into individual spines in the stratum radiatum. We find three different pathways for calcium influx: high-threshold voltage-sensitive calcium channels, NMDA receptors, and an APV-resistant influx consistent with calcium-permeable AMPA or kainate receptors. These pathways vary among different populations of spines and are engaged under different stimulation conditions, with peak calcium concentrations reaching >10 microM. Furthermore, as a result of the biophysical properties of the NMDA receptor, the calcium dynamics of spines are exquisitely sensitive to the temporal coincidence of the input and output of the neuron. Our results confirm that individual spines are chemical compartments that can perform coincidence detection. Finally, we demonstrate that functional studies and optical quantal analysis of single, identified synapses is feasible in mammalian CNS neurons in brain slices.

  16. Transient Influx of nickel in root mitochondria modulates organic acid and reactive oxygen species production in nickel hyperaccumulator Alyssum murale.

    Science.gov (United States)

    Agrawal, Bhavana; Czymmek, Kirk J; Sparks, Donald L; Bais, Harsh P

    2013-03-01

    Mitochondria are important targets of metal toxicity and are also vital for maintaining metal homeostasis. Here, we examined the potential role of mitochondria in homeostasis of nickel in the roots of nickel hyperaccumulator plant Alyssum murale. We evaluated the biochemical basis of nickel tolerance by comparing the role of mitochondria in closely related nickel hyperaccumulator A. murale and non-accumulator Alyssum montanum. Evidence is presented for the rapid and transient influx of nickel in root mitochondria of nickel hyperaccumulator A. murale. In an early response to nickel treatment, substantial nickel influx was observed in mitochondria prior to sequestration in vacuoles in the roots of hyperaccumulator A. murale compared with non-accumulator A. montanum. In addition, the mitochondrial Krebs cycle was modulated to increase synthesis of malic acid and citric acid involvement in nickel hyperaccumulation. Furthermore, malic acid, which is reported to form a complex with nickel in hyperaccumulators, was also found to reduce the reactive oxygen species generation induced by nickel. We propose that the interaction of nickel with mitochondria is imperative in the early steps of nickel uptake in nickel hyperaccumulator plants. Initial uptake of nickel in roots results in biochemical responses in the root mitochondria indicating its vital role in homeostasis of nickel ions in hyperaccumulation.

  17. Lateral root emergence in Arabidopsis is dependent on transcription factor LBD29 regulation of auxin influx carrier LAX3.

    Science.gov (United States)

    Porco, Silvana; Larrieu, Antoine; Du, Yujuan; Gaudinier, Allison; Goh, Tatsuaki; Swarup, Kamal; Swarup, Ranjan; Kuempers, Britta; Bishopp, Anthony; Lavenus, Julien; Casimiro, Ilda; Hill, Kristine; Benkova, Eva; Fukaki, Hidehiro; Brady, Siobhan M; Scheres, Ben; Péret, Benjamin; Bennett, Malcolm J

    2016-09-15

    Lateral root primordia (LRP) originate from pericycle stem cells located deep within parental root tissues. LRP emerge through overlying root tissues by inducing auxin-dependent cell separation and hydraulic changes in adjacent cells. The auxin-inducible auxin influx carrier LAX3 plays a key role concentrating this signal in cells overlying LRP. Delimiting LAX3 expression to two adjacent cell files overlying new LRP is crucial to ensure that auxin-regulated cell separation occurs solely along their shared walls. Multiscale modeling has predicted that this highly focused pattern of expression requires auxin to sequentially induce auxin efflux and influx carriers PIN3 and LAX3, respectively. Consistent with model predictions, we report that auxin-inducible LAX3 expression is regulated indirectly by AUXIN RESPONSE FACTOR 7 (ARF7). Yeast one-hybrid screens revealed that the LAX3 promoter is bound by the transcription factor LBD29, which is a direct target for regulation by ARF7. Disrupting auxin-inducible LBD29 expression or expressing an LBD29-SRDX transcriptional repressor phenocopied the lax3 mutant, resulting in delayed lateral root emergence. We conclude that sequential LBD29 and LAX3 induction by auxin is required to coordinate cell separation and organ emergence. PMID:27578783

  18. Analysis of affinely equivalent Boolean functions

    Institute of Scientific and Technical Information of China (English)

    MENG QingShu; ZHANG HuanGuo; YANG Min; WANG ZhangYi

    2007-01-01

    By some basic transforms and invariant theory, we give two results: 1) an algorithm,which can be used to judge if two Boolean functions are affinely equivalent and to obtain the equivalence relationship if they are equivalent. This is useful in studying Boolean functions and in engineering. For example, we classify all 8-variable homogeneous bent functions of degree 3 into two classes; 2) Reed-Muller codes R(4,6)/R(1,6), R(3,7)/R(1,7) are classified efficiently.

  19. On Metrizability of Invariant Affine Connections

    CERN Document Server

    Tanaka, Erico

    2011-01-01

    The metrizability problem for a symmetric affine connection on a manifold, invariant with respect to a group of diffeomorphisms G, is considered. We say that the connection is G-metrizable, if it is expressible as the Levi-Civita connection of a G-invariant metric field. In this paper we analyze the G-metrizability equations for the rotation group G = SO(3), acting canonically on three- and four-dimensional Euclidean spaces. We show that the property of the connection to be SO(3)-invariant allows us to find complete explicit description of all solutions of the SO(3)-metrizability equations.

  20. Latest European coelacanth shows Gondwanan affinities.

    Science.gov (United States)

    Cavin, Lionel; Forey, Peter L; Buffetaut, Eric; Tong, Haiyan

    2005-06-22

    The last European fossil occurrence of a coelacanth is from the Mid-Cretaceous of the English Chalk (Turonian, 90 million years ago). Here, we report the discovery of a coelacanth from Late Cretaceous non-marine rocks in southern France. It consists of a left angular bone showing structures that imply close phylogenetic affinities with some extinct Mawsoniidae. The closest relatives are otherwise known from Cretaceous continental deposits of southern continents and suggest that the dispersal of freshwater organisms from Africa to Europe occurred in the Late Cretaceous.

  1. Affine Coherent States in Quantum Cosmology

    CERN Document Server

    Malkiewicz, Przemyslaw

    2015-01-01

    A brief summary of the application of coherent states in the examination of quantum dynamics of cosmological models is given. We discuss quantization maps, phase space probability distributions and semiclassical phase spaces. The implementation of coherent states based on the affine group resolves the hardest singularities, renders self-adjoint Hamiltonians without boundary conditions and provides a completely consistent semi-classical description of the involved quantum dynamics. We consider three examples: the closed Friedmann model, the anisotropic Bianchi Type I model and the deep quantum domain of the Bianchi Type IX model.

  2. Measuring an antibody affinity distribution molecule by molecule

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, Andrew M [Los Alamos National Laboratory; Werner, James H [Los Alamos National Laboratory; Temirov, Jamshid [INVITROGEN

    2008-01-01

    Single molecule fluorescence mIcroscopy was used to observe the binding and unbinding of hapten decorated quantum dots with individual surface immobilized antibodies. The fluorescence time history from an individual antibody site can be used to calculate its binding affinity. While quantum dot blinking occurs during these measurements, we describe a simple empirical method to correct the apparent/observed affinity to account for the blinking contribution. The combination of many single molecule affinity measurements from different antibodies yields not only the average affinity, it directly measures the full shape and character of the surface affinity distribution function.

  3. Measurements of Urban Area-Wide CO2 and CH4 Fluxes as part of the Indianapolis Flux Experiment (INFLUX)

    Science.gov (United States)

    Shepson, P.; Callahan, B.; Cambaliza, M. L.; Davis, K. J.; Hardesty, R.; Iraci, L. T.; Gurney, K. R.; Karion, A.; Lauvaux, T.; McGowan, L. E.; Miles, N. L.; Moser, B.; Newberger, T.; Possolo, A.; Razlivanov, I. N.; Richardson, S.; Samarov, D. V.; Sarmiento, D.; Stirm, B.; Sweeney, C.; Turnbull, J. C.; Whetstone, J. R.

    2012-12-01

    The Indianapolis Flux Experiment (INFLUX) was created in order to develop and evaluate methods for the measurement of greenhouse gas emission fluxes from urban environments. Such methods are important for a variety of reasons, including that more than half the global population now resides in cities, and because it is likely that many CO2 emissions reductions strategies will be implemented on local, largely urban, scales. INFLUX is using Indianapolis as a test case for measurements of urban scale greenhouse gas fluxes, because it is a fairly isolated urban environment with tractable meteorology, and a well-developed emission inventory (Vulcan/Hestia). INFLUX aims to quantify and reduce the uncertainty limits for such flux determinations, and to define the uncertainties for individual and combined approaches. The project currently combines a network of towers (currently 10 with 12 possible by the end of 2012) at which CO, CO2 and CH4 are measured, along with periodic flask sampling for 14CO2 and ~50 other trace gases and isotopes. Aircraft-based measurements of CO2, CH4 and H2O, along with flask samples for a variety of gases including 14CO2 are conducted from a light twin aircraft that enables flux measurements using the on-board turbulence/wind measurements via mass balance or eddy covariance methods. As of August of 2012 INFLUX has a Total Carbon Column Observing Network (TCCON) Fourier Transform Spectrometer at a downwind site, measuring column total CO2, CH4, H2O (and other greenhouse gases). The data from these tower, TCCON and aircraft measurements are then used in an inverse-modeling approach, using the Weather Research and Forecast model with chemistry (WRF-Chem) and the Lagrangian Particle Dispersion Model (LDPM) to yield estimates of the urban area flux at 1 km2 resolution. When aggregated these fluxes can be compared to estimates derived from aircraft mass-balance estimates, and the 14CO2 and CO data are used to extract the fossil fuel component of the

  4. Connection between the Affine and conformal Affine Toda models and their Hirota's solution

    International Nuclear Information System (INIS)

    It is shown that the Affine Toda models (AT) constitute a gauge fixed version of the Conformal Affine Toda model (CAT). This result enables one to map every solution of the AT models into an infinite number of solutions of the corresponding CAT models, each one associated to a point of the orbit of the conformal group. The Hirota's τ-function are introduced and soliton solutions for the AT and CAT models associated to SL (r+1) and SP (r) are constructed. (author)

  5. Aptamer Affinity Maturation by Resampling and Microarray Selection.

    Science.gov (United States)

    Kinghorn, Andrew B; Dirkzwager, Roderick M; Liang, Shaolin; Cheung, Yee-Wai; Fraser, Lewis A; Shiu, Simon Chi-Chin; Tang, Marco S L; Tanner, Julian A

    2016-07-19

    Aptamers have significant potential as affinity reagents, but better approaches are critically needed to discover higher affinity nucleic acids to widen the scope for their diagnostic, therapeutic, and proteomic application. Here, we report aptamer affinity maturation, a novel aptamer enhancement technique, which combines bioinformatic resampling of aptamer sequence data and microarray selection to navigate the combinatorial chemistry binding landscape. Aptamer affinity maturation is shown to improve aptamer affinity by an order of magnitude in a single round. The novel aptamers exhibited significant adaptation, the complexity of which precludes discovery by other microarray based methods. Honing aptamer sequences using aptamer affinity maturation could help optimize a next generation of nucleic acid affinity reagents. PMID:27346322

  6. Aspects of affine Toda field theory

    International Nuclear Information System (INIS)

    The report is devoted to properties of the affine Toda field theory, the intention being to highlight a selection of curious properties that should be explicable in terms of the underlying group theory but for which in most cases there are no explanation. The motivation for exploring the ideas contained in this report came principally from the recent work of Zamolodchikov concerning the two dimensional Ising model at critical temperature perturbed by a magnetic field. Hollowood and Mansfield pointed out that since Toda field theory is conformal the perturbation considered by Zamolodchikov might well be best regarded as a perturbation of a Toda field theory. This work made it seem plausible that the theory sought by Zamolodchikov was actually affine E8 Toda field theory. However, this connection required an imaginary value of the coupling constant. Investigations here concerning exact S-matrices use a perturbative approach based on real coupling and the results differ in various ways from those thought to correspond to perturbed conformal field theory. A further motivation is to explore the connection between conformal and perturbed conformal field theories in other contexts using similar ideas. (N.K.)

  7. Exploring Fluorous Affinity by Liquid Chromatography.

    Science.gov (United States)

    Catani, Martina; Guzzinati, Roberta; Marchetti, Nicola; Pasti, Luisa; Cavazzini, Alberto

    2015-07-01

    Terms such as "fluorous affinity" and "fluorophilicity" have been used to describe the unique partition and sorption properties often exhibited by highly fluorinated organic compounds, that is molecules rich in sp(3) carbon-fluorine bonds. In this work, we made use of a highly fluorinated stationary phase and a series of benzene derivatives to study the effect of one single perfluorinated carbon on the chromatographic behavior and adsorption properties of molecules. For this purpose, the adsorption equilibria of α,α,α-trifluorotoluene, toluene, and other alkylbenzenes have been studied by means of nonlinear chromatography in a variety of acetonitrile/water eluents. Our results reveal that one single perfluorinated carbon is already enough to induce a drastic change in the adsorption properties of molecules on the perfluorinated stationary phase. In particular, it has been found that adsorption is monolayer if the perfluoroalkyl carbon is present but that, when this unit is missing, molecules arrange as multilayer stack structures. These findings can contribute to the understanding of molecular mechanisms of fluorous affinity. PMID:26047527

  8. Affine Mirkovi\\'c-Vilonen polytopes

    CERN Document Server

    Baumann, Pierre; Tingley, Peter

    2011-01-01

    Each integrable lowest weight representation of a symmetrizable Kac-Moody Lie algebra g has a crystal in the sense of Kashiwara, which describes its combinatorial properties. For a given g, there is a limit crystal, usually denoted by B(-\\infty), which contains all the other crystals. When g is finite dimensional, a convex polytope, called the Mirkovi\\'c-Vilonen polytope, can be associated to each element in B(-\\infty). This polytope sits in the dual space of a Cartan subalgebra of g, and its edges are parallel to the roots of g. In this paper, we generalize this construction to the case where g is a symmetric affine Kac-Moody algebra. The datum of the polytope must however be complemented by partitions attached to the edges parallel to the imaginary root \\delta. We prove that these decorated polytopes are characterized by conditions on their normal fans and on their 2-faces. In addition, we discuss how our polytopes provide an analog of the notion of Lusztig datum for affine Kac-Moody algebras. Our main tool...

  9. Affine conformal vectors in space-time

    Science.gov (United States)

    Coley, A. A.; Tupper, B. O. J.

    1992-05-01

    All space-times admitting a proper affine conformal vector (ACV) are found. By using a theorem of Hall and da Costa, it is shown that such space-times either (i) admit a covariantly constant vector (timelike, spacelike, or null) and the ACV is the sum of a proper affine vector and a conformal Killing vector or (ii) the space-time is 2+2 decomposable, in which case it is shown that no ACV can exist (unless the space-time decomposes further). Furthermore, it is proved that all space-times admitting an ACV and a null covariantly constant vector (which are necessarily generalized pp-wave space-times) must have Ricci tensor of Segré type {2,(1,1)}. It follows that, among space-times admitting proper ACV, the Einstein static universe is the only perfect fluid space-time, there are no non-null Einstein-Maxwell space-times, and only the pp-wave space-times are representative of null Einstein-Maxwell solutions. Otherwise, the space-times can represent anisotropic fluids and viscous heat-conducting fluids, but only with restricted equations of state in each case.

  10. sup 86 Rb(K) influx and ( sup 3 H)ouabain binding by human platelets: Evidence for beta-adrenergic stimulation of Na-K ATPase activity

    Energy Technology Data Exchange (ETDEWEB)

    Turaihi, K.; Khokher, M.A.; Barradas, M.A.; Mikhailidis, D.P.; Dandona, P. (Royal Free Hospital and School of Medicine, London (England))

    1989-08-01

    Although active transport of potassium into human platelets has been demonstrated previously, there is hitherto no evidence that human platelets have an ouabain-inhibitable Na-K ATPase in their membrane. The present study demonstrates active rubidium (used as an index of potassium influx), {sup 86}Rb(K), influx into platelets, inhibitable by ouabain, and also demonstrates the presence of specific ({sup 3}H)ouabain binding by the human platelet. This {sup 86}Rb(K) influx was stimulated by adrenaline, isoprenaline, and salbutamol, but noradrenaline caused a mild inhibition. Active {sup 86}Rb(K) influx by platelets was inhibited markedly by timolol, mildly by atenolol, but not by phentolamine. Therefore, active {sup 86}Rb(K) influx in human platelets is enhanced by stimulation of beta adrenoceptors of the beta 2 subtype. The platelet may therefore replace the leukocyte in future studies of Na-K ATPase activity. This would be a considerable advantage in view of the ease and rapidity of preparation of platelets.

  11. A composition for isolating an influx of stratum waters in a well and a method for producing it

    Energy Technology Data Exchange (ETDEWEB)

    Valiyev, I.Sh.; Kuvandykov, I.Sh.; Sokolov, B.B.

    1981-01-01

    Proposed is a composition for isolating an influx of stratum water into a well, which contains an emulsifier - an aqueous solution of diethanolamide of fatty acids with 10-16 carbon atoms and a dispersed phase, which is distinguished by the fact that in order to improve the insulating properties of the composition, it contains paraffin as the dispersed phase with the following component ration in percent by weight: paraffin, 10-70; aqueous solution of diethanolamide of fatty acids with 10-16 carbon atoms, 30-90; diethanolamides of fatty acids with 10-16 carbon atoms, 0.5-6 and water, the remainder. The disperse phase - parafin - in a melted form is emulsified in an aqueous solution of the emulsifier, heated above the melting point of the paraffin, with subsequent natural cooling of the obtained direct emulsion to hardening of the dispersed phase.

  12. Synthesis and characterization of BaFe{sub 2}As{sub 2} single crystals grown by in-flux technique

    Energy Technology Data Exchange (ETDEWEB)

    Garitezi, T.M.; Adriano, C.; Rosa, P.F.S.; Bittar, E.M.; Bufaical, L.; Almeida, R.L.; Granado, E.; Pagliuso, P.G., E-mail: thalesmg@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAM), SP (Brazil). Instituto de Fisica Gleb Wataghin; Grant, T; Fisk, Z. [University of California, Irvine, CA (United States); Avila, M.A.; Ribeiro, R.A. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas; Kuhns, P.L.; Reyes, A.P.; Urbano, R.R. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL (United States)

    2013-08-15

    We report a detailed characterization of BaFe{sub 2}As{sub 2} single crystals grown by a metallic In-flux technique, an alternative to well-established growth routes using FeAs self- or Sn-flux. Electrical resistivity, magnetic susceptibility, nuclear magnetic resonance, and energy dispersive spectroscopy measurements showed no evidence of flux incorporation. More importantly, our results demonstrate that BaFe{sub 2}As{sub 2} single crystals grown by In-flux have extremely high quality. To explore the efficiency of the In-flux growth method, we have also prepared nearly optimally doped superconducting samples of Ba(Fe{sub 1} {sub -x} M {sub x} ){sub 2}As{sub 2} (M = Co, Cu, Ni, and Ru). Among other interesting features, this alternative chemical substitution method has led to enhancement of the maximum T{sub c} for most dopings. (author)

  13. Affine connection form of Regge calculus

    CERN Document Server

    Khatsymovsky, V M

    2015-01-01

    Regge action is represented analogously to how the Palatini action for general relativity (GR) as some functional of the metric and a general connection as independent variables represents the Einstein-Hilbert action. The piecewise flat (or simplicial) spacetime of Regge calculus is equipped with some world coordinates and some piecewise affine metric which is completely defined by the set of edge lengths and the world coordinates of the vertices. The conjugate variables are the general nondegenerate matrices on the 3-simplices which play a role of a general discrete connection. Our previous result on some representation of the Regge calculus action in terms of the local Euclidean (Minkowsky) frame vectors and orthogonal connection matrices as independent variables is somewhat modified for the considered case of the general linear group GL(4,R) of the connection matrices. As a result, we have some action invariant w. r. t. arbitrary change of coordinates of the vertices (and related GL(4,R) transformations in...

  14. Affine and Projective Tree Metric Theorems

    CERN Document Server

    Harel, Matan; Pachter, Lior

    2011-01-01

    The tree metric theorem provides a combinatorial four point condition that characterizes dissimilarity maps derived from pairwise compatible split systems. A similar (but weaker) four point condition characterizes dissimilarity maps derived from circular split systems (Kalmanson metrics). The tree metric theorem was first discovered in the context of phylogenetics and forms the basis of many tree reconstruction algorithms, whereas Kalmanson metrics were first considered by computer scientists, and are notable in that they are a non-trivial class of metrics for which the traveling salesman problem is tractable. We present a unifying framework for these theorems based on combinatorial structures that are used for graph planarity testing. These are (projective) PC-trees, and their affine analogs, PQ-trees. In the projective case, we generalize a number of concepts from clustering theory, including hierarchies, pyramids, ultrametrics and Robinsonian matrices, and the theorems that relate them. As with tree metric...

  15. Effectively nonlocal metric-affine gravity

    CERN Document Server

    Golovnev, Alexey; Sandstad, Marit

    2015-01-01

    In metric-affine theories of gravity such as the C-theories, the spacetime connection is associated to a metric that is nontrivially related to the physical metric. In this article, such theories are rewritten in terms of a single metric and it is shown that they can be recast as effectively nonlocal gravity. With some assumptions, known ghost-free theories with non-singular and cosmologically interesting properties may be recovered. Relations between different formulations are analysed at both perturbative and nonperturbative levels taking carefully into account subtleties with boundary conditions in the presence of integral operators in the action, and equivalences between theories related by nonlocal redefinitions of the fields are verified at the level of equations of motion. This suggests a possible geometrical interpretation of nonlocal gravity as an emergent property of non-Riemannian spacetime structure.

  16. Effectively nonlocal metric-affine gravity

    Science.gov (United States)

    Golovnev, Alexey; Koivisto, Tomi; Sandstad, Marit

    2016-03-01

    In metric-affine theories of gravity such as the C-theories, the spacetime connection is associated to a metric that is nontrivially related to the physical metric. In this article, such theories are rewritten in terms of a single metric, and it is shown that they can be recast as effectively nonlocal gravity. With some assumptions, known ghost-free theories with nonsingular and cosmologically interesting properties may be recovered. Relations between different formulations are analyzed at both perturbative and nonperturbative levels, taking carefully into account subtleties with boundary conditions in the presence of integral operators in the action, and equivalences between theories related by nonlocal redefinitions of the fields are verified at the level of equations of motion. This suggests a possible geometrical interpretation of nonlocal gravity as an emergent property of non-Riemannian spacetime structure.

  17. Data Stream Clustering With Affinity Propagation

    KAUST Repository

    Zhang, Xiangliang

    2014-07-09

    Data stream clustering provides insights into the underlying patterns of data flows. This paper focuses on selecting the best representatives from clusters of streaming data. There are two main challenges: how to cluster with the best representatives and how to handle the evolving patterns that are important characteristics of streaming data with dynamic distributions. We employ the Affinity Propagation (AP) algorithm presented in 2007 by Frey and Dueck for the first challenge, as it offers good guarantees of clustering optimality for selecting exemplars. The second challenging problem is solved by change detection. The presented StrAP algorithm combines AP with a statistical change point detection test; the clustering model is rebuilt whenever the test detects a change in the underlying data distribution. Besides the validation on two benchmark data sets, the presented algorithm is validated on a real-world application, monitoring the data flow of jobs submitted to the EGEE grid.

  18. Affine trajectory correction for nonholonomic mobile robots

    CERN Document Server

    Pham, Quang-Cuong

    2011-01-01

    Planning trajectories for nonholonomic systems is difficult and computationally expensive. When facing unexpected events, it may therefore be preferable to deform in some way the initially planned trajectory rather than to re-plan entirely a new one. We suggest here a method based on affine transformations to make such deformations. This method is exact and fast: the deformations and the resulting trajectories can be computed algebraically, in one step, and without any trajectory re-integration. To demonstrate the possibilities offered by this new method, we use it to derive position correction, orientation correction, obstacle avoidance and feedback control algorithms for the general class of planar wheeled robots and for a tridimensional underwater vehicle.

  19. Fas mRNA expression and calcium influx change in H2O2-induced apoptotic hepatocytes in vitro

    Institute of Scientific and Technical Information of China (English)

    Qi-Ping Lu; Lei Tian

    2005-01-01

    AIM: To investigate the relationship between Fas gene expression and calcium influx change in peroxide-induced apoptotic hepatocytes and the possible molecular mechanism of Rxa in protecting hepatocytes.METHODS: Single-cell Fas mRNA expression in H2O2-exposed L02 hepatocytes with or without treatment of Rxa,an extract from an anti-peroxidant, Radix Salviae Miltiorrhizae,was determined by all-cell patch clamp and single-cell reverse transcriptase polymerase chain reaction (RT-PCR). Transient calcium influx change ([Ca2+]i) in the cells was evaluated with all-cell patch clamp micro-fluorescence single-cytosolic free Ca2+ concentration technique. Fas protein expression, early apoptotic index (annexin-V+) and cell membrane change inthe cells were evaluated by immunohistochemistry, flow cytometry (FCM) and scan electron microscopy respectively.RESULTS: In cells exposed to H2O2 for 2 h, the specific lane for Fas mRNA was vivid on electrophoresis, with increased Fas protein expression, [Ca2+]i (from 143.66±34.21 to 1115.28±227.16), annexin-V+ index (from 4.00±0.79 to 16.18±0.72) and membrane vesicle formation. However, in cells exposed to H2O2 but pre-treated with Rxa, there was no increase in Fas mRNA or protein expression and [Ca2+]i (103.56±28.92). Annexin-V+ index (8.92±1.44) was lower than the controls (P<0.01), and the cell membrane was intact.CONCLUSION: H2O2 induces apoptosis of L02 cells by increasing cytosolic [Ca2+]i, and inducing Fas mRNA and protein expression. Rxa protects the L02 cells from apoptosis through anti-peroxidation, inhibition of calcium overloading and prevention of the activation of cytosolic Fas signal pathway.

  20. Leukotriene B4 mediates macrophage influx and pulmonary hypertension in bleomycin-induced chronic neonatal lung injury.

    Science.gov (United States)

    Ee, Mong Tieng; Kantores, Crystal; Ivanovska, Julijana; Wong, Mathew J; Jain, Amish; Jankov, Robert P

    2016-08-01

    Systemically-administered bleomycin causes inflammation, arrested lung growth, and pulmonary hypertension (PHT) in the neonatal rat, similar to human infants with severe bronchopulmonary dysplasia (BPD). Leukotrienes (LTs) are inflammatory lipid mediators produced by multiple cell types in the lung. The major LTs, LTB4 and cysteinyl LTs, are suggested to contribute to BPD, but their specific roles remain largely unexplored in experimental models. We hypothesized that LTs are increased in bleomycin-induced BPD-like injury, and that inhibition of LT production would prevent inflammatory cell influx and thereby ameliorate lung injury. Rat pups were exposed to bleomycin (1 mg·kg(-1)·day(-1) ip) or vehicle (control) from postnatal days 1-14 and were treated with either zileuton (5-lipoxygenase inhibitor), montelukast (cysteinyl LT1 receptor antagonist), or SC57461A (LTA4 hydrolase inhibitor) 10 mg·kg(-1)·day(-1) ip. Bleomycin led to increased lung content of LTB4, but not cysteinyl LTs. Bleomycin-induced increases in tissue neutrophils and macrophages and lung contents of LTB4 and tumor necrosis factor-α were all prevented by treatment with zileuton. Treatment with zileuton or SC57461A also prevented the hemodynamic and structural markers of chronic PHT, including raised pulmonary vascular resistance, increased Fulton index, and arterial wall remodeling. However, neither treatment prevented impaired alveolarization or vascular hypoplasia secondary to bleomycin. Treatment with montelukast had no effect on macrophage influx, PHT, or on abnormal lung structure. We conclude that LTB4 plays a crucial role in lung inflammation and PHT in experimental BPD. Agents targeting LTB4 or LTB4-mediated signaling may have utility in infants at risk of developing BPD-associated PHT. PMID:27317685

  1. Nelfinavir inhibits intra-mitochondrial calcium influx and protects brain against hypoxic-ischemic injury in neonatal mice.

    Directory of Open Access Journals (Sweden)

    Irina V Utkina-Sosunova

    Full Text Available Nelfinavir (NLF, an antiretroviral agent, preserves mitochondrial membranes integrity and protects mature brain against ischemic injury in rodents. Our study demonstrates that in neonatal mice NLF significantly limits mitochondrial calcium influx, the event associated with protection of the brain against hypoxic-ischemic insult (HI. Compared to the vehicle-treated mice, cerebral mitochondria from NLF-treated mice exhibited a significantly greater tolerance to the Ca(2+-induced membrane permeabilization, greater ADP-phosphorylating activity and reduced cytochrome C release during reperfusion. Pre-treatment with NLF or Ruthenium red (RuR significantly improved viability of murine hippocampal HT-22 cells, reduced Ca(2+ content and preserved membrane potential (Ψm in mitochondria following oxygen-glucose deprivation (OGD. Following histamine-stimulated Ca(2+ release from endoplasmic reticulum, in contrast to the vehicle-treated cells, the cells treated with NLF or RuR also demonstrated reduced Ca(2+ content in their mitochondria, the event associated with preserved Ψm. Because RuR inhibits mitochondrial Ca(2+ uniporter, we tested whether the NLF acts via the mechanism similar to the RuR. However, in contrast to the RuR, in the experiment with direct interaction of these agents with mitochondria isolated from naïve mice, the NLF did not alter mitochondrial Ca(2+ influx, and did not prevent Ca(2+ induced collapse of the Ψm. These data strongly argues against interaction of NLF and mitochondrial Ca(2+ uniporter. Although the exact mechanism remains unclear, our study is the first to show that NLF inhibits intramitochondrial Ca(2+ flux and protects developing brain against HI-reperfusion injury. This novel action of NLF has important clinical implication, because it targets a fundamental mechanism of post-ischemic cell death: intramitochondrial Ca(2+ overload → mitochondrial membrane permeabilization → secondary energy failure.

  2. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

    Science.gov (United States)

    Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

    2013-06-01

    The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3.

  3. Heterogeneous abnormalities of in-vivo left ventricular calcium influx and function in mouse models of muscular dystrophy cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Greally Elizabeth

    2013-01-01

    Full Text Available Abstract Background Manganese-enhanced cardiovascular magnetic resonance (MECMR can non-invasively assess myocardial calcium influx, and calcium levels are known to be elevated in muscular dystrophy cardiomyopathy based on cellular studies. Methods Left ventricular functional studies and MECMR were performed in mdx mice (model of Duchenne Muscular Dystrophy, 24 and 40 weeks and Sgcd−/− mice (Limb Girdle Muscular Dystrophy 2 F, 16 and 32 weeks, compared to wild type controls (C57Bl/10, WT. Results Both models had left ventricular hypertrophy at the later age compared to WT, though the mdx mice had reduced stroke volumes and the Sgcd−/− mice increased heart rate and cardiac index. Especially at the younger ages, MECMR was significantly elevated in both models (both Pmdx mice (PSgcd−/− mice (PSgcd−/− mice had increased heart rates, to determine the role of heart rate in MECMR we studied the hyperpolarization-activated cyclic nucleotide-gated channel inhibitor ZD 7288 which selectively reduces heart rate. This reduced heart rate and MECMR in all mouse groups. However, when looking at the time course of reduction of MECMR in the Sgcd−/− mice at up to 5 minutes of the manganese infusion when heart rates were matched to the WT mice, MECMR was still significantly elevated in the Sgcd−/− mice (P Conclusions Despite both mouse models exhibiting increased in-vivo calcium influx at an early stage in the development of the cardiomyopathy before left ventricular hypertrophy, there are distinct phenotypical differences between the 2 models in terms of heart rates, hemodynamics and responses to calcium channel inhibitors.

  4. Better well control through safe drilling margin identification, influx analysis and direct bottom hole pressure control method for deep water

    Energy Technology Data Exchange (ETDEWEB)

    Veeningen, Daan [National Oilwell Varco IntelliServ (NOV), Houston, TX (United States)

    2012-07-01

    Currently, well control events are almost exclusively detected by using surface measurements. Measuring a volume increase in the 'closed loop' mud circulation system; a standpipe pressure decrease; or changes in a variety of drilling parameters provide indicators of a kick. Especially in deep water, where the riser comprises a substantial section of the well bore, early kick detection is paramount for limiting the severity of a well bore influx and improve the ability to regain well control. While downhole data is presently available from downhole tools nearby the bit, available data rates are sparse as mud pulse telemetry bandwidth is limited and well bore measurements compete with transmission of other subsurface data. Further, data transfer is one-directional, latency is significant and conditions along the string are unknown. High-bandwidth downhole data transmission system, via a wired or networked drill string system, has the unique capability to acquire real-time pressure and temperature measurement at a number of locations along the drill string. This system provides high-resolution downhole data available at very high speed, eliminating latency and restrictions that typically limit the availability of downhole data. The paper describes well control opportunities for deep water operations through the use of downhole data independent from surface measurements. First, the networked drill string provides efficient ways to identify pore pressure, fracture gradient, and true mud weight that comprise the safe drilling margin. Second, the independent measurement capability provides early kick detection and improved ability to analyze an influx even with a heterogeneous mud column through distributed along-string annular pressure measurements. Third, a methodology is proposed for a direct measurement method using downhole real-time pressure for maintaining constant bottom hole pressure during well kills in deep water. (author)

  5. Classical affine W-algebras associated to Lie superalgebras

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Uhi Rinn, E-mail: uhrisu1@math.snu.ac.kr [Department of Mathematical Sciences, Seoul National University, GwanAkRo 1, Gwanak-Gu, Seoul 151-747 (Korea, Republic of)

    2016-02-15

    In this paper, we prove classical affine W-algebras associated to Lie superalgebras (W-superalgebras), which can be constructed in two different ways: via affine classical Hamiltonian reductions and via taking quasi-classical limits of quantum affine W-superalgebras. Also, we show that a classical finite W-superalgebra can be obtained by a Zhu algebra of a classical affine W-superalgebra. Using the definition by Hamiltonian reductions, we find free generators of a classical W-superalgebra associated to a minimal nilpotent. Moreover, we compute generators of the classical W-algebra associated to spo(2|3) and its principal nilpotent. In the last part of this paper, we introduce a generalization of classical affine W-superalgebras called classical affine fractional W-superalgebras. We show these have Poisson vertex algebra structures and find generators of a fractional W-superalgebra associated to a minimal nilpotent.

  6. Indefinite Affine Hyperspheres Admitting a Pointwise Symmetry. Part 2

    Directory of Open Access Journals (Sweden)

    Christine Scharlach

    2009-10-01

    Full Text Available An affine hypersurface M is said to admit a pointwise symmetry, if there exists a subgroup G of Aut(T_pM for all p in M, which preserves (pointwise the affine metric h, the difference tensor K and the affine shape operator S. Here, we consider 3-dimensional indefinite affine hyperspheres, i.e. S = HId (and thus S is trivially preserved. In Part 1 we found the possible symmetry groups G and gave for each G a canonical form of K. We started a classification by showing that hyperspheres admitting a pointwise Z_2 × Z_2 resp. R-symmetry are well-known, they have constant sectional curvature and Pick invariant J < 0 resp. J = 0. Here, we continue with affine hyperspheres admitting a pointwise Z_3- or SO(2-symmetry. They turn out to be warped products of affine spheres (Z_3 or quadrics (SO(2 with a curve.

  7. Abacus models for parabolic quotients of affine Weyl groups

    CERN Document Server

    Hanusa, Christopher R H

    2011-01-01

    We introduce abacus diagrams that describe minimal length coset representatives in affine Weyl groups of types B, C, and D. These abacus diagrams use a realization of the affine Weyl group of type C due to Eriksson to generalize a construction of James for the symmetric group. We also describe several combinatorial models for these parabolic quotients that generalize classical results in affine type A related to core partitions.

  8. On invariant measures of finite affine type tilings

    OpenAIRE

    Petite, S.

    2004-01-01

    In this paper, we consider tilings of the hyperbolic 2-space, built with a finite number of polygonal tiles, up to affine transformation. To such a tiling T, we associate a space of tilings: the continuous hull Omega(T) on which the affine group acts. This space Omega(T) inherits a solenoid structure whose leaves correspond to the orbits of the affine group. First we prove the finite harmonic measures of this laminated space correspond to finite invariant measures for the affine group action....

  9. The cohomology of the affine Deligne-Lusztig varieties in the affine flag manifold of $GL_2$

    CERN Document Server

    Ivanov, Alexander

    2009-01-01

    This paper studies affine Deligne-Lusztig varieties in the affine flag manifold of GL_2. At first we determine all such varieties up to isomorphy. After this we investigate the representations of the sigma-stabilizer of an element b of the group on the etale cohomology of the affine Deligne-Lusztig variety X_w(b). We describe such representations as inductions from compact subgroups and in terms of noncuspidal representations.

  10. Essential adaptation of the calcium influx assay into liposomes with entrapped arsenazo III for studies on the possible calcium translocating properties of acidic phospholipids

    NARCIS (Netherlands)

    Smaal, Erik B.; Mandersloot, Jacqueline G.; Kruijff, B. de; Gier, Johannes de

    1985-01-01

    An adapted version of the Ca2+ influx assay of Weissmann et al. (Weissmann, G., Anderson, P., Serhan, C., Samuelson, E. and Goodman, E. (1980) Proc. Natl. Acad. Sci. USA 77, 1506–1510) is presented for studies on the possible ionophoretic properties of acidic phospholipids. This method is based on t

  11. Ca2+influx insensitive to organic Ca2+entry blockers contributes to noradrenaline-induced contractions of the isolated guinea pig aorta

    NARCIS (Netherlands)

    Gouw, M.A.M.; Wilffert, B.; Wermelskirchen, D.; Van Zwieten, P.A.

    1990-01-01

    We determined the contribution of intracellular Ca2+to the noradrenaline (NA, 3 x 10-5mmol/l)-induced contraction of the isolated guinea pig aorta. Since only about 55% of the NA-induced contraction could be attributed to intracellular Ca2+release, we assumed that a Ca2+influx component contributes

  12. Effect of the dB-c-AMP and forskolin on 45Ca influx, net Ca uptake and tension on rabbit aortic smooth muscle

    International Nuclear Information System (INIS)

    The effect of dibutiryl-adenosine-3',5'-cyclic-monophosphate (dB-c-AMP) and forskolin on aortic tension and 45Ca influx were measured. dB-c-AMP reduced both the rate of force development and the maximal tension achieved in solutions containing various K+ concentrations. Stimulated 45Ca influx was also reduced however to a lesser extent than was the tension. Forskolin showed more marked effects of a similar nature. Thus, both these agents which increase intracellular c-AMP caused a rightward shift in the curve expressing force(ordinate) as a function of Ca influx (abscissa). Consequently, they found that dB-c-AMP stimulated more net Ca to be taken up by the sarcoplasmic reticulum(SR) at the same influx rate. The conclusion that c-AMP produced these effects by stimulating Ca uptake into the superficial SR was supported by the finding that dB-c-AMP increased the amount of Ca taken up into a caffeine releasable fraction

  13. Effect of dB-c-AMP and forskolin on the 45Ca influx, net Ca uptake and tension in rabbit aortic smooth muscle

    International Nuclear Information System (INIS)

    The effects of dibutyril-adenosine-3',5'-cyclic monophosphate (dB-c-AMP) and forskolin on aortic tension and 45Ca influx were measured. dB-c-AMP reduced both the rate of force development and the maximal tension achieved in solutions containing various K+ concentrations. Stimulated 45Ca influx was also reduced, however, to a lesser extent than was the tension. Forskolin showed more marked effects of a similar nature. Thus, both these agents which increase intracellular c-AMP caused a rightward shift in the curve expressing force (ordinate) as a function of Ca2+ influx (abscissa). Consequently, the authors found that dB-c-AMP stimulated more net Ca to be taken up by sarcoplasmic reticulum (SR) at the same influx rate. The conclusion that c-AMP produced these effects by stimulating Ca uptake into the superficial SR was supported by the finding that dB-c-AMP increased the amount of Ca taken up into a caffeine releasable fraction. (Auth.)

  14. Striving for Empathy: Affinities, Alliances and Peer Sexuality Educators

    Science.gov (United States)

    Fields, Jessica; Copp, Martha

    2015-01-01

    Peer sexuality educators' accounts of their work reveal two approaches to empathy with their students: affinity and alliance. "Affinity-based empathy" rests on the idea that the more commonalities sexuality educators and students share (or perceive they share), the more they will be able to empathise with one another, while…

  15. Isolation of bovine serum albumin from whey using affinity chromatography

    NARCIS (Netherlands)

    Besselink, T.; Janssen, A.E.M.; Boom, R.M.

    2015-01-01

    The adsorption of bovine serum albumin (BSA) to a chromatography resin with immobilised llama antibody fragments as affinity ligands was investigated. The maximum adsorption capacity of the affinity resin was 21.6 mg mL-1 with a Langmuir equilibrium constant of 20.4 mg mg-1. Using packed bed chromat

  16. Affine group formulation of the Standard Model coupled to gravity

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Ching-Yi, E-mail: l2897107@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Taiwan (China); Ita, Eyo, E-mail: ita@usna.edu [Department of Physics, US Naval Academy, Annapolis, MD (United States); Soo, Chopin, E-mail: cpsoo@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Taiwan (China)

    2014-04-15

    In this work we apply the affine group formalism for four dimensional gravity of Lorentzian signature, which is based on Klauder’s affine algebraic program, to the formulation of the Hamiltonian constraint of the interaction of matter and all forces, including gravity with non-vanishing cosmological constant Λ, as an affine Lie algebra. We use the hermitian action of fermions coupled to gravitation and Yang–Mills theory to find the density weight one fermionic super-Hamiltonian constraint. This term, combined with the Yang–Mills and Higgs energy densities, are composed with York’s integrated time functional. The result, when combined with the imaginary part of the Chern–Simons functional Q, forms the affine commutation relation with the volume element V(x). Affine algebraic quantization of gravitation and matter on equal footing implies a fundamental uncertainty relation which is predicated upon a non-vanishing cosmological constant. -- Highlights: •Wheeler–DeWitt equation (WDW) quantized as affine algebra, realizing Klauder’s program. •WDW formulated for interaction of matter and all forces, including gravity, as affine algebra. •WDW features Hermitian generators in spite of fermionic content: Standard Model addressed. •Constructed a family of physical states for the full, coupled theory via affine coherent states. •Fundamental uncertainty relation, predicated on non-vanishing cosmological constant.

  17. Synthesis of tetracycline analogs and their bone affinities

    Institute of Scientific and Technical Information of China (English)

    Wen Cai Huang; Hu Zheng; Ling Ling Weng

    2008-01-01

    Tetracycline analogs were designed and synthesized and their bone affinities were tested on hydroxyapatite. The results showedthat the carbonyl-amide-enol structure in A ring and phenol-ketone structure in BCD ring may be responsible for tetracycline's highbone affinity and either A ring or BCD ring has a planar conformation is essential.

  18. Capillary electrophoresis-based assessment of nanobody affinity and purity

    NARCIS (Netherlands)

    Haselberg, Rob; Oliveira, Sabrina; van der Meel, Roy; Somsen, Govert W; de Jong, Gerhardus J

    2014-01-01

    Drug purity and affinity are essential attributes during development and production of therapeutic proteins. In this work, capillary electrophoresis (CE) was used to determine both the affinity and composition of the biotechnologically produced "nanobody" EGa1, the binding fragment of a heavy-chain-

  19. Self-affine roughness influence on redox reaction charge admittance

    NARCIS (Netherlands)

    Palasantzas, G

    2005-01-01

    In this work we investigate the influence of self-affine electrode roughness on the admittance of redox reactions during facile charge transfer kinetics. The self-affine roughness is characterized by the rms roughness amplitude w, the correlation length xi and the roughness exponent H (0

  20. Frame-independent mechanics:geometry on affine bundles

    OpenAIRE

    Grabowska, K.; Grabowski, J.; Urbanski, P.

    2005-01-01

    Main ideas of the differential geometry on affine bundles are presented. Affine counterparts of Lie algebroid and Poisson structures are introduced and discussed. The developed concepts are applied in a frame-independent formulation of the time-dependent and the Newtonian mechanics.

  1. Peptide Nucleic Acids Having Enhanced Binding Affinity and Sequence Specificity

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than a corresponding DNA strand, and exhibit increased sequence specificity and binding affinity. Methods of increasing binding affinity and sequence specificity of peptide nucleic aci...

  2. High affinity retinoic acid receptor antagonists: analogs of AGN 193109.

    Science.gov (United States)

    Johnson, A T; Wang, L; Gillett, S J; Chandraratna, R A

    1999-02-22

    A series of high affinity retinoic acid receptor (RAR) antagonists were prepared based upon the known antagonist AGN 193109 (2). Introduction of various phenyl groups revealed a preference for substitution at the para-position relative to the meta-site. Antagonists with the highest affinities for the RARs possessed hydrophobic groups, however, the presence of polar functionality was also well tolerated.

  3. Pathway for Ca2+ influx into cells by trichosporin-B-VIa, an alpha-aminoisobutyric acid-containing peptide, from the fungus Trichoderma polysporum.

    Science.gov (United States)

    Tachikawa, E; Nogimori, K; Takahashi, S; Mizuma, K; Itoh, K; Kashimoto, T; Nagaoka, Y; Iida, A; Fujita, T

    1996-06-13

    Trichosporin (TS) -B-VIa, a fungal alpha-aminoisobutyric acid (Aib) -containing peptide consisting of 19 amino acid residues and a phenylalaninol, produced both 45Ca2+ influx into bovine adrenal chromaffin cells and catecholamine secretion from the cells. The secretion induced by TS-B-VIa at lower concentrations (2-5 microM) was completely dependent on the external Ca2+, while that induced by TS-B-VIa at higher concentrations (10-30 microM) was partly independent of the Ca2+. The concentration-response curves (2-5 microM) for the TS-B-VIa-induced Ca2+ influx and secretion correlated well. The TS-B-VIa (at 5 microM) -induced secretion was not antagonized by diltiazem, a blocker of L-type voltage-sensitive Ca2+ channels. The treatment of fura-2-loaded C6 glioma cells with TS-B-VIa (2-5 microM) led to an increase in the intracellular free Ca2+ concentration ([Ca2+]i) in a concentration-dependent manner but the stimulatory effects of TS-B-VIa on [Ca2+]i were only slightly observed in Ca(2+)-free medium, indicating that TS-B-VIa causes Ca2+ influx from the external medium into the C6 cells. The TS-B-VIa-induced increase in [Ca2+]i in the C6 cells was not antagonized by diltiazem and by SK&F 96365, a novel blocker of receptor-mediated Ca2+ entry. High K+ increased neither [Ca2+]1 in the C6 cells nor Mn2+ influx into the cells, while TS-B-VIa increased Mn2+ influx. Also in other non-excitable cells, bovine platelets, similar results were obtained. These results strongly suggest that the mechanism of Ca2+ influx by TS-B-VIa at the lower concentrations is distinct from the event of Ca2+ influx through receptor-operated or L-type voltage-sensitive Ca2+ channels in both excitable cells (the chrornaffin cells) and non-excitable cells (the C6 cells and the platelets) and that TS-B-VIa per se may form Ca(2+)-permeable ion channels in biological membranes. On the other hand, the peptide at the higher concentrations seems to damage cell membranes. PMID:8679651

  4. Nitric Oxide Blocks Blue Light-Induced K+ Influx by Elevating the Cytosolic Ca2+ Concentration in Vicia faba L.Guard Cells

    Institute of Scientific and Technical Information of China (English)

    Xiang Zhao; Yuan-Yuan Li; Hui-Li Xiao; Chang-Shui Xu; Xiao Zhang

    2013-01-01

    Ca2+ plays a pivotal role in nitric oxide (NO)-promoted stomatal closure.However,the function of Ca2+ in NO inhibition of blue light (BL)-induced stomatal opening remains largely unknown.Here,we analyzed the role of Ca2+ in the crosstalk between BL and NO signaling in Vicia faba L.guard cells.Extracellular Ca2+ modulated the BL-induced stomatal opening in a dose-dependent manner,and an application of 5 μM Ca2+ in the pipette solution significantly inhibited BL-activated K+ influx.Sodium nitroprusside (SNP),a NO donor,showed little effect on BL-induced K+ influx and stomatal opening response in the absence of extracellular Ca2+,but K+ influx and stomatal opening were inhibited by SNP when Ca2+ was added to the bath solution.Interestingly,although both SNP and BL could activate the plasma membrane Ca2+ channels and induce the rise of cytosolic Ca2+,the change in levels of Ca2+ channel activity and cytosolic Ca2+ concentration were different between SNP and BL treatments.SNP at 100 μM obviously activated the plasma membrane Ca2+ channels and induced cytosolic Ca2+ rise by 102.4%.In contrast,a BL pulse (100 μmol/m2 per s for 30 s) slightly activated the Ca2+ channels and resulted in a Ca2+ rise of only 20.8%.Consistently,cytosolic Ca2+ promoted K+ influx at 0.5 μM or below,and significantly inhibited K+ influx at 5 μM or above.Taken together,our findings indicate that Ca2+ plays dual and distinctive roles in the crosstalk between BL and NO signaling in guard cells,mediating both the BL-induced K+ influx as an activator at a lower concentration and the NO-blocked K+ influx as an inhibitor at a higher concentration.

  5. The effect of hypothermia on influx of leukocytes in the digital lamellae of horses with oligofructose-induced laminitis.

    Science.gov (United States)

    Godman, Jennifer D; Burns, Teresa A; Kelly, Carlin S; Watts, Mauria R; Leise, Britta S; Schroeder, Eric L; van Eps, Andrew W; Belknap, James K

    2016-10-01

    Sepsis-related laminitis (SRL) is a common complication in the septic/endotoxemic critically-ill equine patient, in which lamellar injury and failure commonly lead to crippling distal displacement of the distal phalanx. Similar to organ injury in human sepsis, lamellar injury in SRL has been associated with inflammatory events, including the influx of leukocytes into the lamellar tissue and markedly increased expression of a wide array of inflammatory mediators at the onset of Obel grade 1 (OG1) laminitis. The only treatment reported both clinically and experimentally to protect the lamellae in SRL, local hypothermia ("cryotherapy"), has been demonstrated to effectively inhibit lamellar expression of multiple inflammatory mediators when initiated at the time of administration of a carbohydrate overload in experimental models of SRL. However, the effect of hypothermia on leukocyte influx into affected tissue has not been assessed. We hypothesized that cryotherapy inhibits leukocyte emigration into the digital lamellae in SRL. Immunohistochemical staining using leukocyte markers MAC387 (marker of neutrophils, activated monocytes) and CD163 (monocyte/macrophage-specific marker) was performed on archived lamellar tissue samples from an experimental model of SRL in which one forelimb was maintained at ambient temperature (AMB) and one forelimb was immersed in ice water (ICE) immediately following enteral oligofructose administration (10g/kg, n=14 horses). Lamellae were harvested at 24h post-oligofructose administration (DEV, n=7) or at the onset of OG1 laminitis (OG1, n=7). Both MAC387-positive and CD163-positive cells were counted by a single blinded investigator on images [n=10 (40× fields/digit for MAC387 and 20x fields/digit for CD163)] obtained using Aperio microscopy imaging analysis software. Data were assessed for normality and analyzed with a paired t-test and one-way ANOVA with significance set at pmodel. This study demonstrated that hypothermia of the distal

  6. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    Science.gov (United States)

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture.

  7. Detection of protein-protein interactions using tandem affinity purification.

    Science.gov (United States)

    Goodfellow, Ian; Bailey, Dalan

    2014-01-01

    Tandem affinity purification (TAP) is an invaluable technique for identifying interaction partners for an affinity tagged bait protein. The approach relies on the fusion of dual tags to the bait before separate rounds of affinity purification and precipitation. Frequently two specific elution steps are also performed to increase the specificity of the overall technique. In the method detailed here, the two tags used are protein G and a short streptavidin binding peptide; however, many variations can be employed. In our example the tags are separated by a cleavable tobacco etch virus protease target sequence, allowing for specific elution after the first round of affinity purification. Proteins isolated after the final elution step in this process are concentrated before being identified by mass spectrometry. The use of dual affinity tags and specific elution in this technique dramatically increases both the specificity and stringency of the pull-downs, ensuring a low level of background nonspecific interactions.

  8. IMPLEMENTASI ENKRIPSI DEKRIPSI ALGORITMA AFFINE CIPHER BERBASIS ANDROID

    Directory of Open Access Journals (Sweden)

    Sasono Wibowo

    2014-11-01

    Full Text Available Perkembangan Teknologi Informasi yang cukup pesat khususnya dalam bidang komunikasi menjadikan komunikasi sangat mudah namun dalam implementasinya perlu adanya keamanan tentang informasi yang disampaikan. Dalam komunikasi antar orang pasti memiliki pembicaraan informasi yang bersifat privat atau orang lain tidak boleh tahu tentang pembicaraan yang terjadi. Diperlukannya keamanan untuk menjaga kerahasiaan informasi pada saat komunikasi. Masyarakat lebih sering menggunakan komunikasi dengan telepon seluler karena dinilai mudah dibawa dan tidak repot menggunakannya. Kriptografi yang biasa dikenal sebagai ilmu yang mempelajari bagaimana cara menyembunyikan pesan bisa diterapkan dalam aplikasi pada telepon seluler sebagai contoh smartphone android. Dengan mengimplementasikan algoritma affine cipher maka aplikasi yang akan dibuat bisa mengubah isi pesan yang ada dan dapat mengamankan informasi yang ada. Algoritma affine cipher merupakan perkembangan dari algoritma caesar dimana algoritma affine cipher menggunakan dua kunci. Dengan mengimplementasikan algoritma affine cipher ke dalam android maka diharapkan kita bisa menyimpan informasi dari siapapun tanpa terbaca. Kata Kunci : Kriptografi, Affine Cipher, android, Implementasi, Informasi

  9. Chasing polys: Interdisciplinary affinity and its connection to physics identity

    Science.gov (United States)

    Scott, Tyler D.

    This research is based on two motivations that merge by means of the frameworks of interdisciplinary affinity and physics identity. First, a goal of education is to develop interdisciplinary abilities in students' thinking and work. But an often ignored factor is students interests and beliefs about being interdisciplinary. Thus, this work develops and uses a framework called interdisciplinary affinity. It encompasses students interests in making connections across disciplines and their beliefs about their abilities to make those connections. The second motivation of this research is to better understand how to engage more students with physics. Physics identity describes how a student sees themselves in relation to physics. By understanding how physics identity is developed, researchers and educators can identify factors that increase interest and engagement in physics classrooms. Therefore, physics identity was used in conjunction with interdisciplinary affinity. Using a mixed methods approach, this research used quantitative data to identify the relationships interdisciplinary affinity has with physics identity and the physics classroom. These connections were explored in more detail using a case study of three students in a high school physics class. Results showed significant and positive relationships between interdisciplinary affinity and physics identity, including the individual interest and recognition components of identity. It also identified characteristics of physics classrooms that had a significant, positive relationship with interdisciplinary affinity. The qualitative case study highlighted the importance of student interest to the relationship between interdisciplinary affinity and physics identity. It also identified interest and mastery orientation as key to understanding the link between interdisciplinary affinity and the physics classroom. These results are a positive sign that by understanding interdisciplinary affinity and physics identity

  10. Regulation of the High-Affinity Nitrate Transport System in Wheat Roots by Exogenous Abscisic Acid and Glutamine

    Institute of Scientific and Technical Information of China (English)

    Chao Cai; Xue-Qiang Zhao; Yong-Guan Zhu; Bin Li; Yi-Ping Tong; Zhen-Sheng Li

    2007-01-01

    Nitrate is a major nitrogen (N) source for most crops.Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels.Understanding how nitrate uptake is regulated will help us engineer crops with improved nitrate uptake efficiency.The present study investigated the regulation of the high-affinity nitrate transport system (HATS) by exogenous abscisic acid (ABA) and glutamine (Gin) in wheat (Triticum aestivum L.) roots.Wheat seedlings grown in nutrient solution containing 2 mmollL nitrate as the only nitrogen source for 2 weeks were deprived of N for 4d and were then transferred to nutrient solution containing 50 μmol/L ABA, and 1 mmol/L Gin in the presence or absence of 2 mmol/L nitrate for 0, 0.5, 1, 2, 4, and 8 h.Treated wheat plants were then divided into two groups.One group of plants was used to investigate the mRNA levels of the HATS components NRT2 and NAR2 genes in roots through semi-quantitative RT-PCR approach, and the other set of plants were used to measure high-affinity nitrate influx rates in a nutrient solution containing 0.2 mmol/L 15 N-labeled nitrate.The results showed that exogenous ABA induced the expression of the TaNRT2.1, TaNRT2.2, TaNRT2.3, TaNAR2.1, and TaNAR2.2 genes in roots when nitrate was not present in the nutrient solution, but did not further enhance the induction of these genes by nitrate.Glutamine, which has been shown to inhibit the expression of NRT2 genes when nitrate is present in the growth media, did not inhibit this induction.When Gin was supplied to a nitrate-free nutrient solution, the expression of these five genes in roots was induced.These results imply that the inhibition by Gin of NRT2 expression occurs only when nitrate is present in the growth media.Although exogenous ABA and Gin induced HATS genes in the roots of wheat, they did not induce nitrate influx.

  11. Optimal affine-invariant matching: performance characterization

    Science.gov (United States)

    Costa, Mauro S.; Haralick, Robert M.; Shapiro, Linda G.

    1992-04-01

    The geometric hashing scheme proposed by Lamdan and Wolfson can be very efficient in a model-based matching system, not only in terms of the computational complexity involved, but also in terms of the simplicity of the method. In a recent paper, we discussed errors that can occur with this method due to quantization, stability, symmetry, and noise problems. These errors make the original geometric hashing technique unsuitable for use on the factory floor. Beginning with an explicit noise model, which the original Lamdan and Wolfson technique lacks, we derived an optimal approach that overcomes these problems. We showed that the results obtained with the new algorithm are clearly better than the results from the original method. This paper addresses the performance characterization of the geometric hashing technique, more specifically the affine-invariant point matching, applied to the problem of recognizing and determining the pose of sheet metal parts. The experiments indicate that with a model having 10 to 14 points, with 2 points of the model undetected and 10 extraneous points detected, and with the model points perturbed by Gaussian noise of standard deviation 3 (0.58 of range), the average amount of computation required to obtain an answer is equivalent to trying 11 of the possible three-point bases. The misdetection rate, measured by the percentage of correct bases matches that fail to verify, is 0.9. The percentage of incorrect bases that successfully produced a match that did verify (false alarm rate) is 13. And, finally, 2 of the experiments failed to find a correct match and verify it. Results for experiments with real images are also presented.

  12. Convulsant bicuculline modifies CNS muscarinic receptor affinity

    Directory of Open Access Journals (Sweden)

    Rodríguez de Lores Arnaiz Georgina

    2006-04-01

    Full Text Available Abstract Background Previous work from this laboratory has shown that the administration of the convulsant drug 3-mercaptopropionic acid (MP, a GAD inhibitor, modifies not only GABA synthesis but also binding of the antagonist [3H]-quinuclidinyl benzilate ([3H]-QNB to central muscarinic receptors, an effect due to an increase in affinity without modifications in binding site number. The cholinergic system has been implicated in several experimental epilepsy models and the ability of acetylcholine to regulate neuronal excitability in the neocortex is well known. To study the potential relationship between GABAergic and cholinergic systems with seizure activity, we analyzed the muscarinic receptor after inducing seizure by bicuculline (BIC, known to antagonize the GABA-A postsynaptic receptor subtype. Results We analyzed binding of muscarinic antagonist [3H]-QNB to rat CNS membranes after i.p. administration of BIC at subconvulsant (1.0 mg/kg and convulsant (7.5 mg/kg doses. Subconvulsant BIC dose failed to develop seizures but produced binding alteration in the cerebellum and hippocampus with roughly 40% increase and 10% decrease, respectively. After convulsant BIC dose, which invariably led to generalized tonic-clonic seizures, binding increased 36% and 15% to cerebellar and striatal membranes respectively, but decreased 12% to hippocampal membranes. Kd value was accordingly modified: with the subconvulsant dose it decreased 27% in cerebellum whereas it increased 61% in hippocampus; with the convulsant dose, Kd value decreased 33% in cerebellum but increased 85% in hippocampus. No change in receptor number site was found, and Hill number was invariably close to unity. Conclusion Results indicate dissimilar central nervous system area susceptibility of muscarinic receptor to BIC. Ligand binding was modified not only by a convulsant BIC dose but also by a subconvulsant dose, indicating that changes are not attributable to the seizure process

  13. Electron affinities of atoms, molecules, and radicals

    International Nuclear Information System (INIS)

    We review briefly but comprehensively the theoretical, semiempirical and experimental methods employed to determine electron affinities (EAs) of atoms, molecules and radicals, and summarize the EA data obtained by these methods. The detailed processes underlying the principles of the experimental methods are discussed very briefly. It is, nonetheless, instructive to recapitulate the definition of EA and those of the related quantities, namely, the vertical detachment energy, VDE, and the vertical attachment energy, VAE. The EA of an atom is defined as the difference in total energy between the ground state of the neutral atom (plus the electron at rest at infinity) and its negative ion. The EA of a molecule is defined as the difference in energy between the neutral molecule plus an electron at rest at infinity and the molecular negative ion when both, the neutral molecules and the negative ion, are in their ground electronic, vibrational and rotational states. The VDE is defined as the minimum energy required to eject the electron from the negative ion (in its ground electronic and nuclear state) without changing the internuclear separation; since the vertical transition may leave the neutral molecule in an excited vibrational/rotational state, the VDE, although the same as the EA for atoms is, in general, different (larger than), from the EA for molecules. Similarly, the VAE is defined as the difference in energy between the neutral molecule in its ground electronic, vibrational and rotational states plus an electron at rest at infinity and the molecular negative ion formed by addition of an electron to the neutral molecule without allowing a change in the intermolecular separation of the constituent nuclei; it is a quantity appropriate to those cases where the lowest negative ion state lies above the ground states of the neutral species and is less or equal to EA

  14. Capsaicin sensitizes TRAIL-induced apoptosis through Sp1-mediated DR5 up-regulation: Involvement of Ca2+ influx

    International Nuclear Information System (INIS)

    Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various malignant cells, several cancers including human hepatocellular carcinoma (HCC) exhibit potent resistance to TRAIL-induced cell death. The aim of this study is to evaluate the anti-cancer potential of capsaicin in TRAIL-induced cancer cell death. As indicated by assays that measure phosphatidylserine exposure, mitochondrial activity and activation of caspases, capsaicin potentiated TRAIL-resistant cells to lead to cell death. In addition, we found that capsaicin induces the cell surface expression of TRAIL receptor DR5, but not DR4 through the activation Sp1 on its promoter region. Furthermore, we investigated that capsaicin-induced DR5 expression and apoptosis are inhibited by calcium chelator or inhibitors for calmodulin-dependent protein kinase. Taken together, our data suggest that capsaicin sensitizes TRAIL-mediated HCC cell apoptosis by DR5 up-regulation via calcium influx-dependent Sp1 activation. Highlights: ► Capsaicin sensitizes TRAIL-induced apoptosis through activation of caspases. ► Capsaicin induces expression of DR5 through Sp1 activation. ► Capsaicin activates calcium signaling pathway.

  15. Methodological Principles of Assessing the Volume of Investment Influx from Non-State Pension Funds into the Economy of Ukraine

    Directory of Open Access Journals (Sweden)

    Dmitro Leonov

    2004-11-01

    Full Text Available This article addresses the processes of forming investment resources from nonstate pension funds under current conditions in Ukraine and the laws and regula tions that define the principles of the formation of in vestment institutions. Based on factors that in the near est future will affect the decisionmaking process by which different kinds of investors make payments to non state pension funds, we develop a procedure for assessing the volume of investment influx from nonstate pension funds into the economy and propose a procedure for long and shortterm prognosis of the volume of investment in flux from nonstate pension funds into the Ukrainian economy.

  16. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai

    2011-03-24

    Deposition of ammonium (NH4 +) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4 + is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin transport demonstrated that SSA inhibits root acropetal (rootward) auxin transport while not affecting basipetal (shootward) transport or auxin sensitivity of root cells. Mutant analyses indicated that the auxin influx carrier AUX1, but not the auxin efflux carriers PIN-FORMED (PIN)1 or PIN2, is required for this inhibition of LRP emergence and the observed auxin response. We found that AUX1 expression was modulated by SSA in vascular tissues rather than LR cap cells in roots. Taken together, our results suggest that SSA inhibits LRP emergence in Arabidopsis by interfering with AUX1-dependent auxin transport from shoot to root. © 2011 Blackwell Publishing Ltd.

  17. Alterations in plasma membrane promote overexpression and increase of sodium influx through epithelial sodium channel in hypertensive platelets.

    Science.gov (United States)

    Cerecedo, D; Martínez-Vieyra, Ivette; Sosa-Peinado, Alejandro; Cornejo-Garrido, Jorge; Ordaz-Pichardo, Cynthia; Benítez-Cardoza, Claudia

    2016-08-01

    Platelets are small, anucleated cell fragments that activate in response to a wide variety of stimuli, triggering a complex series of intracellular pathways leading to a hemostatic thrombus formation at vascular injury sites. However, in essential hypertension, platelet activation contributes to causing myocardial infarction and ischemic stroke. Reported abnormalities in platelet functions, such as platelet hyperactivity and hyperaggregability to several agonists, contribute to the pathogenesis and complications of thrombotic events associated with hypertension. Platelet membrane lipid composition and fluidity are determining for protein site accessibility, structural arrangement of platelet surface, and response to appropriate stimuli. The present study aimed to demonstrate whether structural and biochemical abnormalities in lipid membrane composition and fluidity characteristic of platelets from hypertensive patients influence the expression of the Epithelial Sodium Channel (ENaC), fundamental for sodium influx during collagen activation. Wb, cytometry and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assays demonstrated ENaC overexpression in platelets from hypertensive subjects and in relation to control subjects. Additionally, our results strongly suggest a key role of β-dystroglycan as a scaffold for the organization of ENaC and associated proteins. Understanding of the mechanisms of platelet alterations in hypertension should provide valuable information for the pathophysiology of hypertension. PMID:27137675

  18. Noninvasive estimation of the net influx constant using standardized uptake value for quantification of FDG uptake of tumors

    International Nuclear Information System (INIS)

    To reduce the fluctuation of the standardized uptake value (SUV) as the indicator for the 2-(18F)fluoro-2-deoxy-D-glucose (FDG) uptake of tumors, the net influx constant (Ki) was estimated from SUV. The relation was used; Ki=SUV x kp x V0, kp: the elimination rate constant of FDG from plasma and V0: the initial distribution volume of FDG. V0, kp and SUV were calculated, then the estimated Ki was obtained. To enhance the accuracy, the estimated Ki was compared with the actual Ki from 8 patients with head and neck cancer. V0 based on the body weight was 0.1627±0.0329 (ml/g) and showed the weak correlation with the body weight. V0 based on the surface area was 5540±871 (ml/m2) and showed no correlation with the body weight. kp showed no correlation with the blood-sugar level. The high correlation was found between the actual Ki and the estimated Ki. It suggested that Ki is superior to SUV as an index of FDG uptake, and noninvasive estimation of the Ki is useful to standardize the quantification of diagnosis for tumor using FDG-PET. (K.H.)

  19. Alterations in plasma membrane promote overexpression and increase of sodium influx through epithelial sodium channel in hypertensive platelets.

    Science.gov (United States)

    Cerecedo, D; Martínez-Vieyra, Ivette; Sosa-Peinado, Alejandro; Cornejo-Garrido, Jorge; Ordaz-Pichardo, Cynthia; Benítez-Cardoza, Claudia

    2016-08-01

    Platelets are small, anucleated cell fragments that activate in response to a wide variety of stimuli, triggering a complex series of intracellular pathways leading to a hemostatic thrombus formation at vascular injury sites. However, in essential hypertension, platelet activation contributes to causing myocardial infarction and ischemic stroke. Reported abnormalities in platelet functions, such as platelet hyperactivity and hyperaggregability to several agonists, contribute to the pathogenesis and complications of thrombotic events associated with hypertension. Platelet membrane lipid composition and fluidity are determining for protein site accessibility, structural arrangement of platelet surface, and response to appropriate stimuli. The present study aimed to demonstrate whether structural and biochemical abnormalities in lipid membrane composition and fluidity characteristic of platelets from hypertensive patients influence the expression of the Epithelial Sodium Channel (ENaC), fundamental for sodium influx during collagen activation. Wb, cytometry and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assays demonstrated ENaC overexpression in platelets from hypertensive subjects and in relation to control subjects. Additionally, our results strongly suggest a key role of β-dystroglycan as a scaffold for the organization of ENaC and associated proteins. Understanding of the mechanisms of platelet alterations in hypertension should provide valuable information for the pathophysiology of hypertension.

  20. The sodium ion affinities of asparagine, glutamine, histidine and arginine

    Science.gov (United States)

    Wang, Ping; Ohanessian, Gilles; Wesdemiotis, Chrys

    2008-01-01

    The sodium ion affinities of the amino acids Asn, Gln, His and Arg have been determined by experimental and computational approaches (for Asn, His and Arg). Na+-bound heterodimers with amino acid and peptide ligands (Pep1, Pep2) were produced by electrospray ionization. From the dissociation kinetics of these Pep1-Na+-Pep2 ions to Pep1-Na+ and Pep2-Na+, determined by collisionally activated dissociation, a ladder of relative affinities was constructed and subsequently converted to absolute affinities by anchoring the relative values to known Na+ affinities. The Na+ affinities of Asn, His and Arg, were calculated at the MP2(full)/6-311+G(2d,2p)//MP2/6-31G(d) level of ab initio theory. The resulting experimental and computed Na+ affinities are in excellent agreement with one another. These results, combined with those of our previous studies, yield the sodium ion affinities of 18 out of the 20 [alpha]-amino acids naturally occurring in peptides and proteins of living systems.

  1. Genetic Algorithm-based Affine Parameter Estimation for Shape Recognition

    Directory of Open Access Journals (Sweden)

    Yuxing Mao

    2014-06-01

    Full Text Available Shape recognition is a classically difficult problem because of the affine transformation between two shapes. The current study proposes an affine parameter estimation method for shape recognition based on a genetic algorithm (GA. The contributions of this study are focused on the extraction of affine- invariant features, the individual encoding scheme, and the fitness function construction policy for a GA. First, the affine-invariant characteristics of the centroid distance ratios (CDRs of any two opposite contour points to the barycentre are analysed. Using different intervals along the azimuth angle, the different numbers of CDRs of two candidate shapes are computed as representations of the shapes, respectively. Then, the CDRs are selected based on predesigned affine parameters to construct the fitness function. After that, a GA is used to search for the affine parameters with optimal matching between candidate shapes, which serve as actual descriptions of the affine transformation between the shapes. Finally, the CDRs are resampled based on the estimated parameters to evaluate the similarity of the shapes for classification. The experimental results demonstrate the robust performance of the proposed method in shape recognition with translation, scaling, rotation and distortion.

  2. Centro-affine hypersurface immersions with parallel cubic form

    OpenAIRE

    HILDEBRAND, Roland

    2012-01-01

    We consider non-degenerate centro-affine hypersurface immersions in R^n whose cubic form is parallel with respect to the Levi-Civita connection of the affine metric. There exists a bijective correspondence between homothetic families of proper affine hyperspheres with center in the origin and with parallel cubic form, and K\\"ochers conic omega-domains, which are the maximal connected sets consisting of invertible elements in a real semi-simple Jordan algebra. Every level surface of the omega ...

  3. Volatility Components, Affine Restrictions and Non-Normal Innovations

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Dorian, Christian;

    Recent work by Engle and Lee (1999) shows that allowing for long-run and short-run components greatly enhances a GARCH model's ability fit daily equity return dynamics. Using the risk-neutralization in Duan (1995), we assess the option valuation performance of the Engle-Lee model and compare...... models to four conditionally non-normal versions. As in Hsieh and Ritchken (2005), we find that non-affine models dominate affine models both in terms of fitting return and in terms of option valuation. For the affine models we find strong evidence in favor of the component structure for both returns...

  4. Non-Gatherable Triples for Non-Affine Root Systems

    Directory of Open Access Journals (Sweden)

    Ivan Cherednik

    2008-11-01

    Full Text Available This paper contains a complete description of minimal non-gatherable triangle triples in the lambda-sequences for the classical root systems, $F_4$ and $E_6$. Such sequences are associated with reduced decompositions (words in affine and non-affine Weyl groups. The existence of the non-gatherable triples is a combinatorial obstacle for using the technique of intertwiners for an explicit description of the irreducible representations of the (double affine Hecke algebras, complementary to their algebraic-geometric theory.

  5. Synthesis and Image Matching On Structural Patterns Using Affine Transformation

    Directory of Open Access Journals (Sweden)

    S.Vandana

    2012-06-01

    Full Text Available This paper focuses in explaining a Fourier based affine estimator which is applied to the task of Image Synthesis. An affine transformation is an important class of linear 2-D geometric transformations which maps variables into new by applying a linear combination of translation, rotation, scaling and/or shearing operations. Conventional retrieval systems are very effective when knowledge information and query information are in a uniform orientation but fails in recognition when effects such as scaling, orientation exist. But as this technique is based on texture analysis, which is termed the affine estimator, it will even match the images with non-uniform orientation.

  6. Affinity- and topology-dependent bound on current fluctuations

    CERN Document Server

    Pietzonka, Patrick; Seifert, Udo

    2016-01-01

    We provide a proof of a recently conjectured universal bound on current fluctuations in Markovian processes. This bound establishes a link between the fluctuations of an individual observable current, the cycle affinities driving the system into a non-equilibrium steady state, and the topology of the network. The proof is based on a decomposition of the network into independent cycles with both positive affinity and positive stationary cycle current. This formalism allows for a refinement of the bound for systems in equilibrium or with locally vanishing affinities.

  7. ODE/IM correspondence and modified affine Toda field equations

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Katsushi; Locke, Christopher

    2014-08-15

    We study the two-dimensional affine Toda field equations for affine Lie algebra g{sup ^} modified by a conformal transformation and the associated linear equations. In the conformal limit, the associated linear problem reduces to a (pseudo-)differential equation. For classical affine Lie algebra g{sup ^}, we obtain a (pseudo-)differential equation corresponding to the Bethe equations for the Langlands dual of the Lie algebra g, which were found by Dorey et al. in study of the ODE/IM correspondence.

  8. Counteracting effect of TRPC1-associated Ca2+ influx on TNF-α-induced COX-2-dependent prostaglandin E2 production in human colonic myofibroblasts.

    Science.gov (United States)

    Hai, Lin; Kawarabayashi, Yasuhiro; Imai, Yuko; Honda, Akira; Inoue, Ryuji

    2011-08-01

    TNF-α-NF-κB signaling plays a central role in inflammation, apoptosis, and neoplasia. One major consequence of this signaling in the gut is increased production of prostaglandin E(2) (PGE(2)) via cyclooxygenase-2 (COX-2) induction in myofibroblasts, which has been reported to be dependent on Ca(2+). In this study, we explored a potential role of canonical transient receptor potential (TRPC) proteins in this Ca(2+)-mediated signaling using a human colonic myofibroblast cell line CCD-18Co. In CCD-18Co cell, treatment with TNF-α greatly enhanced Ca(2+) influx induced by store depletion along with increased cell-surface expression of TRPC1 protein (but not of the other TRPC isoforms) and induction of a Gd(3+)-sensitive nonselective cationic conductance. Selective inhibition of TRPC1 expression by small interfering RNA (siRNA) or functionally effective TRPC1 antibody targeting the near-pore region of TRPC1 (T1E3) antagonized the enhancement of store-dependent Ca(2+) influx by TNF-α, whereas potentiated TNF-α induced PGE(2) production. Overexpression of TRPC1 in CCD-18Co produced opposite consequences. Inhibitors of NF-κB (curcumin, SN-50) attenuated TNF-α-induced enhancement of TRPC1 expression, store-dependent Ca(2+) influx, and COX-2-dependent PGE(2) production. In contrast, inhibition of calcineurin-nuclear factor of activated T-cell proteins (NFAT) signaling by FK506 or NFAT Activation Inhibitor III enhanced the PGE(2) production without affecting TRPC1 expression and the Ca(2+) influx. Finally, the suppression of store-dependent Ca(2+) influx by T1E3 antibody or siRNA knockdown significantly facilitated TNF-α-induced NF-κB nuclear translocation. In aggregate, these results strongly suggest that, in colonic myofibroblasts, NF-κB and NFAT serve as important positive and negative transcriptional regulators of TNF-α-induced COX-2-dependent PGE(2) production, respectively, at the downstream of TRPC1-associated Ca(2+) influx. PMID:21546578

  9. Improving and Assessing Aircraft-based Greenhouse Gas Emission Rate Measurements at Indianapolis as part of the INFLUX project.

    Science.gov (United States)

    Heimburger, A. M. F.; Shepson, P. B.; Stirm, B. H.; Susdorf, C.; Cambaliza, M. O. L.

    2015-12-01

    Since the Copenhagen accord in 2009, several countries have affirmed their commitment to reduce their greenhouse gas emissions. The United States and Canada committed to reduce their emissions by 17% below 2005 levels, by 2020, Europe by 14% and China by ~40%. To achieve such targets, coherent and effective strategies in mitigating atmospheric carbon emissions must be implemented in the next decades. Whether such goals are actually achieved, they require that reductions are "measurable", "reportable", and "verifiable". Management of greenhouse gas emissions must focus on urban environments since ~74% of CO2 emissions worldwide will be from cities, while measurement approaches are highly uncertain (~50% to >100%). The Indianapolis Flux Experiment (INFLUX) was established to develop, assess and improve top-down and bottom-up quantifications of urban greenhouse gas emissions. Based on an aircraft mass balance approach, we performed a series of experiments focused on the improvement of CO2, CH4 and CO emission rates quantification from Indianapolis, our final objective being to drastically improve the method overall uncertainty from the previous estimate of 50%. In November-December 2014, we conducted nine methodologically identical mass balance experiments in a short period of time (24 days, one downwind distance) for assumed constant total emission rate conditions, as a means to obtain an improved standard deviation of the mean determination. By averaging the individual emission rate determinations, we were able to obtain a method precision of 17% and 16% for CO2 and CO, respectively, at the 95%C.L. CH4 emission rates are highly variable day to day, leading to precision of 60%. Our results show that repetitive sampling can enable improvement in precision of the aircraft top-down methods through averaging.

  10. High influx of carbon in walls of agglutinated foraminifers during the Permian-Triassic transition in global oceans

    Science.gov (United States)

    Nestell, Galina P.; Nestell, Merlynd K.; Ellwood, Brooks B.; Wardlaw, Bruce R.; Basu, Asish R.; Ghosh, Nilotpal; Phuong Lan, Luu Thi; Rowe, Harry D.; Hunt, Andrew G.; Tomkin, Jonathan H.; Ratcliffe, Kenneth T.

    2015-01-01

    The Permian–Triassic mass extinction is postulated to be related to the rapid volcanism that produced the Siberian flood basalt (Traps). Unrelated volcanic eruptions producing several episodes of ash falls synchronous with the Siberian Traps are found in South China and Australia. Such regional eruptions could have caused wildfires, burning of coal deposits, and the dispersion of coal fly ash. These eruptions introduced a major influx of carbon into the atmosphere and oceans that can be recognized in the wallstructure of foraminiferal tests present in survival populations in the boundary interval strata. Analysis of free specimens of foraminifers recovered from residues of conodont samples taken at aPermian–Triassic boundary section at Lung Cam in northern Vietnam has revealed the presence of a significant amount of elemental carbon, along with oxygen and silica, in their test wall structure, but an absence of calcium carbonate. These foraminifers, identified as Rectocornuspira kalhori, Cornuspira mahajeri, and Earlandia spp. and whose tests previously were considered to be calcareous, are confirmed to be agglutinated, and are now referred to as Ammodiscus kalhori and Hyperammina deformis. Measurement of the 207Pb/204Pb ratios in pyrite clusters attached to the foraminiferal tests confirmed that these tests inherited the Pb in their outer layer from carbon-contaminated seawater. We conclude that the source of the carbon could have been either global coal fly ash or forest fire-dispersed carbon, or a combination of both, that was dispersed into the Palaeo-Tethys Ocean immediately after the end-Permian extinction event.

  11. Methyl mercury inhibits short-circuit current and Cl- influx across isolated epipodite of European lobster (Homarus gammarus).

    Science.gov (United States)

    Lucu, Cedomil; Dupcić-Radić, Iris; Tomsić, Sanja

    2009-05-01

    The effect of methyl mercuric chloride (MeHg) on short-circuit current (I(SC)) was studied in the isolated perfused epipodite preparation from the branchial chamber of European lobster (Homarus gammarus) acclimated to dilute seawater. When applied at the apical surface, 0.2, 1.0 and 3.0 microM MeHg depressed I(SC) by a 26%, 81% and 98%, respectively. The half-maximal inhibitory concentration (IC(50)) of apically applied MeHg was 0.6 microM. Basolaterally added MeHg (3.0 microM) had no effect on I(SC), whereas addition of the specific Na(+),K(+)-ATPase inhibitor ouabain (1.5 mM) reduced I(SC) by approximately 90%. Ouabain effects were reversible, and I(SC) fully recovered upon removal of ouabain. The MeHg-induced block of I(SC) was partially reversed by the reducing agent, 1,4-dithiothreitol, suggesting that the formation of S-Hg-S bridges is important in the inhibitory mechanism. A significant reduction of I(SC) and conductance occurred when low Na(+) and Cl(-) salines were substituted. Furthermore, in the low Na(+) saline, J(Cl)(A-->B) fluxes were reduced by about 50%. In the highly conductive epipodite epithelium, coupling of Na(+) and Cl(-) fluxes was suggested. The effects of MeHg on I(SC) in the lobster epipodite are attributed to inhibition of an apical Cl(-) influx. PMID:19038364

  12. Na+ Influx Induced by New Antimalarials Causes Rapid Alterations in the Cholesterol Content and Morphology of Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Sudipta Das

    2016-05-01

    Full Text Available Among the several new antimalarials discovered over the past decade are at least three clinical candidate drugs, each with a distinct chemical structure, that disrupt Na+ homeostasis resulting in a rapid increase in intracellular Na+ concentration ([Na+]i within the erythrocytic stages of Plasmodium falciparum. At present, events triggered by Na+ influx that result in parasite demise are not well-understood. Here we report effects of two such drugs, a pyrazoleamide and a spiroindolone, on intraerythrocytic P. falciparum. Within minutes following the exposure to these drugs, the trophozoite stage parasite, which normally contains little cholesterol, was made permeant by cholesterol-dependent detergents, suggesting it acquired a substantial amount of the lipid. Consistently, the merozoite surface protein 1 and 2 (MSP1 and MSP2, glycosylphosphotidylinositol (GPI-anchored proteins normally uniformly distributed in the parasite plasma membrane, coalesced into clusters. These alterations were not observed following drug treatment of P. falciparum parasites adapted to grow in a low [Na+] growth medium. Both cholesterol acquisition and MSP1 coalescence were reversible upon the removal of the drugs, implicating an active process of cholesterol exclusion from trophozoites that we hypothesize is inhibited by high [Na+]i. Electron microscopy of drug-treated trophozoites revealed substantial morphological changes normally seen at the later schizont stage including the appearance of partial inner membrane complexes, dense organelles that resemble "rhoptries" and apparent nuclear division. Together these results suggest that [Na+]i disruptor drugs by altering levels of cholesterol in the parasite, dysregulate trophozoite to schizont development and cause parasite demise.

  13. Antidiarrheal and Antispasmodic Activities of Buddleja polystachya are Mediated Through Dual Inhibition of Ca(++) Influx and Phosphodiesterase Enzyme.

    Science.gov (United States)

    Rehman, Najeeb-ur; Gilani, Anwarul-Hassan; Khan, Aslam; Nazneen, Maryam; El Gamal, Ali A; Fawzy, Ghada A; Al-Ati, Hanan Y; Abdel-kader, Maged S

    2015-08-01

    This study describes the antidiarrheal and antispasmodic activities of the hydro-alcoholic extract of Buddleja polystachya (Bp.Cr) with possible mode of action explored along with activity-directed fractionation. Bp.Cr and its aqueous (Bp.Aq) and organic fractions, petroleum ether (Bp.Pet), dichloromethane (Bp.DCM), ethylacetate (Bp.EtAc) and butanol (Bp.But), were tested using the in-vivo and in-vitro assays. The crude extract (100-300 mg/kg) showed 20 and 60% protection of castor oil-induced diarrhea in mice. In isolated rabbit jejunum, Bp.Cr like papaverine inhibited spontaneous and high K(+) (80 mM)-induced contractions equi-potently. In guinea-pig ileum, Bp.Cr showed a moderate spasmogenic effect. The activity-directed fractionation revealed that the spasmolytic activity was concentrated in the organic fractions and spasmogenic component in the aqueous fraction. Amongst the organic fractions, BP.DCM and Bp.Pet inhibited spontaneous and high K(+) -induced contractions equi-potently, while Bp.But, like verapamil was more potent against high K(+) . The crude extract and its organic fractions caused rightward shift in the Ca(++) -concentration response curves (CRCs), similar to verapamil, and all except Bp.But potentiated the isoprenaline-inhibitory CRCs to the left, similar to papaverine. The results of this study indicate that the crude extract of B. polystachya possesses antidiarrheal and antispasmodic activities, mediated possibly through dual inhibition of Ca(++) influx and phospodiesterase enzyme. PMID:25975350

  14. Properties of an affine transport equation and its generalized holonomy

    CERN Document Server

    Vines, Justin

    2014-01-01

    We investigate properties of a transport equation that was recently used to study the observer dependence of angular momentum in general relativity. The associated map between the tangent spaces at two points on a curve is affine, and for this reason, the operation was called "affine transport". The map consists of a homogeneous (linear) part given by the parallel transport map along the curve, plus an inhomogeneous part which is related to the development of a curve in a manifold into an affine tangent space (also described as the rolling of a manifold along a tangent space without slipping or twisting). For closed curves, the affine transport equation defines a "generalized holonomy". We use covariant bitensor calculus to compute the generalized holonomy around geodesic polygon loops, specifically for triangles and "parallelogramoids" with sides formed from geodesic segments. For small loops, we recover the well-known result for the leading-order holonomy of parallel transport ($\\sim$ Riemann $\\times$ area)...

  15. A thermodynamic approach to the affinity optimization of drug candidates.

    Science.gov (United States)

    Freire, Ernesto

    2009-11-01

    High throughput screening and other techniques commonly used to identify lead candidates for drug development usually yield compounds with binding affinities to their intended targets in the mid-micromolar range. The affinity of these molecules needs to be improved by several orders of magnitude before they become viable drug candidates. Traditionally, this task has been accomplished by establishing structure activity relationships to guide chemical modifications and improve the binding affinity of the compounds. As the binding affinity is a function of two quantities, the binding enthalpy and the binding entropy, it is evident that a more efficient optimization would be accomplished if both quantities were considered and improved simultaneously. Here, an optimization algorithm based upon enthalpic and entropic information generated by Isothermal Titration Calorimetry is presented.

  16. Elective affinities and economic thought: 1870-1914

    Directory of Open Access Journals (Sweden)

    João Antônio de Paula

    2006-01-01

    Full Text Available This article seeks to demonstrate that the concept of "elective affinities" can be applied to the relations between economic thought, literature, and philosophy. Emphasis is given to Institutionalist thought, the German historical school, and neoclassical thought.

  17. Experimental investigation of streamer affinity for dielectric surfaces

    OpenAIRE

    Trienekens, Dirk; Nijdam, Sander; Akkermans, G.; Plompen, I.; Christen, T.; Ebert, Ute

    2015-01-01

    We have experimentally investigated the affinity of streamers for dielectric surfaces using stroboscopic imaging and stereo photography. Affinity of streamers for dielectric surfaces was found to depend on a wide set of parameters, including pressure, voltage, dielectric material and discharge gap geometry. Our results show that higher relative permittivity, higher pressure, lower voltage, an d asymmetrical sample placement increase the chance of the streamer following the dielectric surface.

  18. A Characterization of Hyperbolic Affine Iterated Function Systems

    CERN Document Server

    Atkins, Ross; Vince, Andrew; Wilson, David C

    2009-01-01

    The two main theorems of this paper provide a characterization of hyperbolic affine iterated function systems defined on Rm. Atsushi Kameyama (Distances on Topological Self-Similar Sets, Proceedings of Symposia in Pure Mathematics, Volume 72.1, 2004) asked the following fundamental question: given a topological self-similar set, does there exist an associated system of contraction mappings? Our theorems imply an affirmative answer to Kameyama's question for self-similar sets derived from affine transformations on Rm.

  19. Peculiarities of Matter Motion in Metric-Affine Gravitational Theory

    OpenAIRE

    Babourova, O. V.; Frolov, B. N.; Koroliov, M. Yu.

    1995-01-01

    On the basis of the Lie derivative method in a metric-affine space-time it is shown that in the metric-affine gravitational theory the energy-momentum conservation law and therefore the equations of the matter motion are the consequence (as in the GR) of the gravitational field equations. The possi- bility of the detection of the space-time non-metric properties is discussed.

  20. Some Inequalities for Lp-mixed Affine Surface Area

    Institute of Scientific and Technical Information of China (English)

    ZHU Xian-yang

    2012-01-01

    In this paper,the concepts of the ith Lp-mixed affine surface area and Lp-polar curvature images are introduced,some new inequalities connecting these new notions with Lp-centroid bodies and p-Blaschke bodies are showed.Moreover,a Blaschke-Santaló type inequality for Lp-mixed affine surface area is established.Our results also imply the similar to the inequalities for Marcus-Lopes,Bergstrom and Ky Fan.

  1. Algebraic volume density property of affine algebraic manifolds

    OpenAIRE

    Kaliman, Shulim; Kutzschebauch, Frank

    2009-01-01

    We introduce the notion of algebraic volume density property for affine algebraic manifolds and prove some important basic facts about it, in particular that it implies the volume density property. The main results of the paper are producing two big classes of examples of Stein manifolds with volume density property. One class consists of certain affine modifications of $\\C^n$ equipped with a canonical volume form, the other is the class of all Linear Algebraic Groups equipped with the left i...

  2. Quantized gauge-affine gravity in the superfiber bundle approach

    OpenAIRE

    Meziane, A.; Tahiri, M

    2004-01-01

    The quantization of gauge-affine gravity within the superfiber bundle formalism is proposed. By introducing an even pseudotensorial 1-superform over a principal superfibre bundle with superconnection, we obtain the geometrical Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST transformations of the fields occurring in such a theory. Reducing the four-dimensional general affine group double-covering to the Poincare group double-covering we also find the BRST and anti-BRST transformations of the f...

  3. Skein Modules from Skew Howe Duality and Affine Extensions

    OpenAIRE

    Queffelec, Hoel

    2013-01-01

    We show that we can release the rigidity of the skew Howe duality process for ${\\mathfrak sl}_n$ knot invariants by rescaling the quantum Weyl group action, and recover skein modules for web-tangles. This skew Howe duality phenomenon can be extended to the affine ${\\mathfrak sl}_m$ case, corresponding to looking at tangles embedded in a solid torus. We investigate the relations between the invariants constructed by evaluation representations (and affinization of them) and usual skein modules,...

  4. Affinity Solvents for Intensified Organics Extraction: Development Challenges and Prospects

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In most organics extraction processes, the commonly used solvents employ solely physical interactions. Therefore, for the recovery and purification of products from complex mixtures, the selectivity and/or capacity of classical solvents towards the desired solutes is usually insufficient, enforcing the need for complex and thus expensive separation schemes. Significant simplification and cost-reduction can be achieved when affinity solvents would be available that are able to recognize the solutes of interest by their molecular structure. The main development challenges to establish such affinity solvents are: Selection and incorporation of molecular recognition and complexation capabilities; Evaluation of extraction capabilities; Efficient recovery and recycling of the affinity solvents; Implementation in industrial extraction equipment. This paper presents how these development challenges are addressed at the University of Twente, going all the way from affinity solvent design and synthesis, via high throughput screening and characterization up to pilot plant evaluation. Essential in the successful development of affinity solvents are structural cooperations with molecular chemists and custom synthesis companies for their design and synthesis. The various aspects are illustrated by several examples where newly developed environmentally benign affinity solvents appeared able to create major breakthroughs. The applications addressed involve oxygenates, sugars, and pharmaceutical ingredients, such as optical isomers and biomolecules.

  5. Rice nitrate transporter OsNPF2.4 functions in low-affinity acquisition and long-distance transport.

    Science.gov (United States)

    Xia, Xiudong; Fan, Xiaorong; Wei, Jia; Feng, Huimin; Qu, Hongye; Xie, Dan; Miller, Anthony J; Xu, Guohua

    2015-01-01

    Plant proteins belonging to the NPF (formerly NRT1/PTR) family are well represented in every genome and function in transporting a wide variety of substrates. In this study, we showed that rice OsNPF2.4 is located in the plasma membrane and is expressed mainly in the epidermis, xylem parenchyma, and phloem companion cells. Functional analysis in oocytes showed that OsNPF2.4 is a pH-dependent, low-affinity NO₃⁻ transporter. Short-term (¹⁵NO₃⁻) influx rate, long-term NO₃⁻ acquisition by root, and upward transfer from root to shoot were decreased by disruption of OsNPF2.4 and increased by OsNPF2.4 overexpression under high NO₃⁻ supply. Moreover, the redistribution of NO₃⁻ in the mutants in comparison with the wild type from the oldest leaf to other organs, particularly to N-starved roots, was dramatically changed. Knockout of OsNPF2.4 decreased rice growth and potassium (K) concentration in xylem sap, root, culm, and sheath, but increased the shoot:root ratio of tissue K under higher NO₃⁻. We conclude that OsNPF2.4 functions in acquisition and long-distance transport of NO₃⁻ , and that altering its expression has an indirect effect on K recycling between the root and shoot. PMID:25332358

  6. An exact calculation of the N2+ and H2+ influx at cathode surface in N2–H2 discharges

    Directory of Open Access Journals (Sweden)

    K.S. Suraj

    2014-01-01

    Full Text Available An exact calculation of N2+ and H2+ influx, at cathode surface in N2–H2 discharge, has been derived using electron impact ionization cross-section at plasma sheath boundary. The analytical formula is very convenient in practical applications. Through the analysis of experimental parameters for glow discharge plasma nitriding, the formula explains, why treatment in an N2–H2 mixture with H2 percentage ∼70% gives most enhanced result.

  7. Safety, efficacy and physiological actions of a lysine-free, arginine-rich formula to treat glutaryl-CoA dehydrogenase deficiency: focus on cerebral amino acid influx.

    Science.gov (United States)

    Strauss, Kevin A; Brumbaugh, Joan; Duffy, Alana; Wardley, Bridget; Robinson, Donna; Hendrickson, Christine; Tortorelli, Silvia; Moser, Ann B; Puffenberger, Erik G; Rider, Nicholas L; Morton, D Holmes

    2011-01-01

    Striatal degeneration from glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type 1, GA1) is associated with cerebral formation and entrapment of glutaryl-CoA and its derivatives that depend on cerebral lysine influx. In 2006 we designed a lysine-free study formula enriched with arginine to selectively block lysine transport across cerebral endothelia and thereby limit glutaryl-CoA production by brain. Between 2006 and present, we treated twelve consecutive children with study formula (LYSx group) while holding all other treatment practices constant. Clinical and biochemical outcomes were compared to 25 GA1 patients (PROx group) treated between 1995 and 2005 with natural protein restriction (dietary lysine/arginine ratio of 1.7±0.3 mg:mg). We used published kinetic parameters of the y+and LAT1 blood-brain barrier transporters to model the influx of amino acids into the brain. Arginine fortification to achieve a mean dietary lysine/arginine ratio of 0.7±0.2 mg:mg was neuroprotective. All 12 LYSx patients are physically and neurologically healthy after 28 aggregate patient-years of follow up (current ages 28±21 months) and there were no adverse events related to formula use. This represents a 36% reduction of neurological risk (95% confidence interval 14-52%, p=0.018) that we can directly attribute to altered amino acid intake. During the first year of life, 20% lower lysine intake and two-fold higher arginine intake by LYSx patients were associated with 50% lower plasma lysine, 3-fold lower plasma lysine/arginine concentration ratio, 42% lower mean calculated cerebral lysine influx, 54% higher calculated cerebral arginine influx, 15-26% higher calculated cerebral influx of several anaplerotic precursors (isoleucine, threonine, methionine, and leucine), 50% less 3-hydroxyglutarate excretion, and a 3-fold lower hospitalization rate (0.8 versus 2.3 hospitalizations per patient per year). The relationship between arginine fortification and plasma lysine

  8. Increased hemoglobin O2 affinity protects during acute hypoxia.

    Science.gov (United States)

    Yalcin, Ozlem; Cabrales, Pedro

    2012-08-01

    Acclimatization to hypoxia requires time to complete the adaptation mechanisms that influence oxygen (O(2)) transport and O(2) utilization. Although decreasing hemoglobin (Hb) O(2) affinity would favor the release of O(2) to the tissues, increasing Hb O(2) affinity would augment arterial O(2) saturation during hypoxia. This study was designed to test the hypothesis that pharmacologically increasing the Hb O(2) affinity will augment O(2) transport during severe hypoxia (10 and 5% inspired O(2)) compared with normal Hb O(2) affinity. RBC Hb O(2) affinity was increased by infusion of 20 mg/kg of 5-hydroxymethyl-2-furfural (5HMF). Control animals received only the vehicle. The effects of increasing Hb O(2) affinity were studied in the hamster window chamber model, in terms of systemic and microvascular hemodynamics and partial pressures of O(2) (Po(2)). Pimonidazole binding to hypoxic areas of mice heart and brain was also studied. 5HMF decreased the Po(2) at which the Hb is 50% saturated with O(2) by 12.6 mmHg. During 10 and 5% O(2) hypoxia, 5HMF increased arterial blood O(2) saturation by 35 and 48% from the vehicle group, respectively. During 5% O(2) hypoxia, blood pressure and heart rate were 58 and 30% higher for 5HMF compared with the vehicle. In addition, 5HMF preserved microvascular blood flow, whereas blood flow decreased to 40% of baseline in the vehicle group. Consequently, perivascular Po(2) was three times higher in the 5HMF group compared with the control group at 5% O(2) hypoxia. 5HMF also reduced heart and brain hypoxic areas in mice. Therefore, increased Hb O(2) affinity resulted in hemodynamics and oxygenation benefits during severe hypoxia. This acute acclimatization process may have implications in survival during severe environmental hypoxia when logistic constraints prevent chronic acclimatization. PMID:22636677

  9. Effects of selenium and topiramate on cytosolic Ca(2+) influx and oxidative stress in neuronal PC12 cells.

    Science.gov (United States)

    Demirci, Seden; Kutluhan, Süleyman; Naziroğlu, Mustafa; Uğuz, Abdülhadi Cihangir; Yürekli, Vedat Ali; Demirci, Kadir

    2013-01-01

    It has been widely suggested that selenium (Se) deficiency play an important role in the pathophysiology of epilepsy. It has been reported that Se provides protection against the neuronal damage in patients and animals with epilepsy by restoring the antioxidant defense mechanism. The neuroprotective effects of topiramate (TPM) have been reported in several studies but the putative mechanism of action remains elusive. We investigated effects of Se and TPM in neuronal PC12 cell by evaluating Ca(2+) mobilization, lipid peroxidation and antioxidant levels. PC12 cells were divided into eight groups namely control, TPM, Se, H(2)O(2), TPM + H(2)O(2), Se + H(2)O(2), Se + TPM and Se + TPM + H(2)O(2). The toxic doses and times of H(2)O(2), TPM and Se were determined by cell viability assay which is used to evaluate cell viability. Cells were incubated with 0.01 mM TPM for 5 h and 500 nM Se for 10 h. Then, the cells were exposed to 0.1 mM H(2)O(2) for 10 h before analysis. The cells in all groups except control, TPM and Se were exposed to H(2)O(2) for 15 min before analysis. Cytosolic Ca(2+) release and lipid peroxidation levels were higher in H(2)O(2) group than in control, Se and TPM combination groups although their levels were decreased by incubation of Se and TPM combination. However, there is no difference on Ca(2+) release in TPM group. Glutathione peroxidase activity, reduced glutathione and vitamin C levels in the cells were lower in H(2)O(2) group than in control, Se and TPM groups although their values were higher in the cells incubated with Se and TPM groups than in H(2)O(2) groups. In conclusion, these results indicate that Se induced protective effects on oxidative stress in PC12 cells by modulating cytosolic Ca(2+) influx and antioxidant levels. TPM modulated also lipid peroxidation and glutathione and vitamin C concentrations in the cell system.

  10. CB1 Cannabinoid Receptor-Dependent and -Independent Inhibition of Depolarization-Induced Calcium Influx in Oiigodendrocytes

    Institute of Scientific and Technical Information of China (English)

    SUSANA MATO; ELENA ALBERDI; CATHERINE LEDENT; MASAHIKO WATANABE; AND CARLOS MATUTE

    2009-01-01

    Regulation of Ca2+ homeostasis plays a critical role in oligodendrocyte function and survival. Canna-binoid CB2 and CB2 receptors have been shown to regulate Ca2+ levels and/or K+ currents in a variety of cell types. In this study we investigated the effect of cannabinoid compounds on the Ca2+ influx elicited in cultured oligodendro-cytes by transient membrane depolarization with an elevated extracellular K+ concentration (50 mM). The CB2 re-ceptor agonist arachidonoyl-chloro-ethanolamide (ACEA) elicited a concentration-dependent inhibition of depolariza-tion-evoked Ca2+ transients in oligodendroglial somata with a maximal effect (94 ± 3)% and an EC50 of 1.3 ±0.03 μM. This activity was mimicked by the CB2/CB2 agonist CP55,940, as well as by the endocannabinoids N-arachidonoyl-ethanolamine (anandamide, AEA) and 2-arachidonoylglycerol (2-AG), whereas the CB2 receptor se-lective agonist JWH133 was ineffective. The CB2 receptor antagonist AM251 (1 μM) also reduced the Ca2+ response evoked by high extracellular K+ and did not prevent the inhibition elicited by ACEA (3 μM). Nevertheless, the a-bility of ACEA and AEA to reduce depolarization-evoked Ca2+ transients was significantly reduced in oligodendro-cytes from CB2 receptor knockout mice, as well as by pretreatment with pertussis toxin. Bath application of the in-wardly rectifying K+ channels (Kir channels) blockers BaCl2 (300 μM) and CsCl2 (1 mM) reduced the size of volt-age-induced Ca2+ influx and partially prevented the inhibitory effect of ACEA. Our results indicate that eannabinoids inhibit depolarization-evoked Ca2+ transients in oligodendrocytes via CB2 receptor-independent and -dependent mech-anisms that involve the activation of PTX-sensitive Gi/o proteins and the blockade of Kir channels. C 2008 Wiley-Liss, Inc.%Ca2+稳态平衡的调节在少突胶质细胞功能和存活中起重要作用.大麻素CB1和CB2受体在许多细胞中调节Ca2+水平和/或K+电流.本文利用培养的少突胶质细

  11. Coenzyme-like ligands for affinity isolation of cholesterol oxidase.

    Science.gov (United States)

    Xin, Yu; Lu, Liushen; Wang, Qing; Zhang, Ling; Tong, Yanjun; Wang, Wu

    2016-05-15

    Two coenzyme-like chemical ligands were designed and synthesized for affinity isolation of cholesterol oxidase (COD). To simulate the structure of natural coenzyme of COD (flavin adenine dinucleotide (FAD)), on Sepharose beads, 5-aminouracil, cyanuric chloride and 1, 4-butanediamine were composed and then modified. The COD gene from Brevibacterium sp. (DQ345780) was expressed in Escherichia coli BL21 (DE3), and then the sorbents were applied to adsorption analysis with the pure enzyme. Subsequently, the captured enzyme was applied to SDS-PAGE and activity analysis. As calculated, the theoretical maximum adsorption (Qmax) of the two affinity sorbents (RL-1 and RL-2) were ∼83.5 and 46.3mg/g wet gel; and the desorption constant Kd of the two sorbents were ∼6.02×10(-4) and 1.19×10(-4)μM. The proteins after cell lysis were applied to affinity isolation, and then after one step of affinity binding on the two sorbents, the protein recoveries of RL-1 and RL-2 were 9.2% and 9.7%; the bioactivity recoveries were 92.7% and 91.3%, respectively. SDS-PAGE analysis revealed that the purities of COD isolated with the two affinity sorbents were approximately 95%. PMID:26856529

  12. Properties of the Affine Invariant Ensemble Sampler in high dimensions

    CERN Document Server

    Huijser, David; Brewer, Brendon J

    2015-01-01

    We present theoretical and practical properties of the affine-invariant ensemble sampler Markov chain Monte Carlo method. In high dimensions the affine-invariant ensemble sampler shows unusual and undesirable properties. We demonstrate this with an $n$-dimensional correlated Gaussian toy problem with a known mean and covariance structure, and analyse the burn-in period. The burn-in period seems to be short, however upon closer inspection we discover the mean and the variance of the target distribution do not match the expected, known values. This problem becomes greater as $n$ increases. We therefore conclude that the affine-invariant ensemble sampler should be used with caution in high dimensional problems. We also present some theoretical results explaining this behaviour.

  13. Single-cell measurement of red blood cell oxygen affinity

    CERN Document Server

    Caprio, Di; Higgins, John M; Schonbrun, Ethan

    2015-01-01

    Oxygen is transported throughout the body by hemoglobin in red blood cells. While the oxygen affinity of blood is well understood and is routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of red blood cell volume and hemoglobin concentration are taken millions of times per day by clinical hematology analyzers and are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume and hemoglobin concentration for individual red blood cells in high-throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.5%, which corresponds to the maximum slope of the oxygen-hemoglobin dissociation curve. In addition, single-cell oxygen affinity is positively correlated with hemoglobin concentr...

  14. k-Schur functions and affine Schubert calculus

    CERN Document Server

    Lam, Thomas; Morse, Jennifer; Schilling, Anne; Shimozono, Mark; Zabrocki, Mike

    2014-01-01

    This book gives an introduction to the very active field of combinatorics of affine Schubert calculus, explains the current state of the art, and states the current open problems. Affine Schubert calculus lies at the crossroads of combinatorics, geometry, and representation theory. Its modern development is motivated by two seemingly unrelated directions. One is the introduction of k-Schur functions in the study of Macdonald polynomial positivity, a mostly combinatorial branch of symmetric function theory. The other direction is the study of the Schubert bases of the (co)homology of the affine Grassmannian, an algebro-topological formulation of a problem in enumerative geometry. This is the first introductory text on this subject. It contains many examples in Sage, a free open source general purpose mathematical software system, to entice the reader to investigate the open problems. This book is written for advanced undergraduate and graduate students, as well as researchers, who want to become familiar with ...

  15. Evaluation Codes from an Affine Veriety Code Perspective

    DEFF Research Database (Denmark)

    Geil, Hans Olav

    2008-01-01

    Evaluation codes (also called order domain codes) are traditionally introduced as generalized one-point geometric Goppa codes. In the present paper we will give a new point of view on evaluation codes by introducing them instead as particular nice examples of affine variety codes. Our study inclu...... includes a reformulation of the usual methods to estimate the minimum distances of evaluation codes into the setting of affine variety codes. Finally we describe the connection to the theory of one-pointgeometric Goppa codes. Contents 4.1 Introduction...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 4.2 Affine variety codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 4.3 Some Gr¨obner basis theoretical tools . . . . . . . . . . . . . . . . . . . . . . . 155 4.4 A bound on the minimum distance of C(I,L) . . . . . . . . . . . . . . . . . . 157 4.5 The Feng-Rao bound...... for C(I,L)? . . . . . . . . . . . . . . . . . . . . . . . . 160 4.6 Using weighted degree orderings . . . . . . . . . . . . . . . . . . . . . . . . . 163 4.7 The order domain conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 4.8 Weight functions and order domains...

  16. Semisupervised Clustering for Networks Based on Fast Affinity Propagation

    Directory of Open Access Journals (Sweden)

    Mu Zhu

    2013-01-01

    Full Text Available Most of the existing clustering algorithms for networks are unsupervised, which cannot help improve the clustering quality by utilizing a small number of prior knowledge. We propose a semisupervised clustering algorithm for networks based on fast affinity propagation (SCAN-FAP, which is essentially a kind of similarity metric learning method. Firstly, we define a new constraint similarity measure integrating the structural information and the pairwise constraints, which reflects the effective similarities between nodes in networks. Then, taking the constraint similarities as input, we propose a fast affinity propagation algorithm which keeps the advantages of the original affinity propagation algorithm while increasing the time efficiency by passing only the messages between certain nodes. Finally, by extensive experimental studies, we demonstrate that the proposed algorithm can take fully advantage of the prior knowledge and improve the clustering quality significantly. Furthermore, our algorithm has a superior performance to some of the state-of-art approaches.

  17. Super-Affine Hierarchies and their Poisson Embeddings

    CERN Document Server

    Toppan, F

    1998-01-01

    The link between (super)-affine Lie algebras as Poisson brackets structures and integrable hierarchies provides both a classification and a tool for obtaining superintegrable hierarchies. The lack of a fully systematic procedure for constructing matrix-type Lax operators, which makes the supersymmetric case essentially different from the bosonic counterpart, is overcome via the notion of Poisson embeddings (P.E.), i.e. Poisson mappings relating affine structures to conformal structures (in their simplest version P.E. coincide with the Sugawara construction). A full class of hierarchies can be recovered by using uniquely Lie-algebraic notions. The group-algebraic properties implicit in the super-affine picture allow a systematic derivation of reduced hierarchies by imposing either coset conditions or hamiltonian constraints (or possibly both).

  18. Enhancing Community Detection By Affinity-based Edge Weighting Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-05

    Community detection refers to an important graph analytics problem of finding a set of densely-connected subgraphs in a graph and has gained a great deal of interest recently. The performance of current community detection algorithms is limited by an inherent constraint of unweighted graphs that offer very little information on their internal community structures. In this paper, we propose a new scheme to address this issue that weights the edges in a given graph based on recently proposed vertex affinity. The vertex affinity quantifies the proximity between two vertices in terms of their clustering strength, and therefore, it is ideal for graph analytics applications such as community detection. We also demonstrate that the affinity-based edge weighting scheme can improve the performance of community detection algorithms significantly.

  19. Ferromagnetic Levan Composite: An Affinity Matrix to Purify Lectin

    Directory of Open Access Journals (Sweden)

    Renata Angeli

    2009-01-01

    Full Text Available A simple and inexpensive procedure used magnetite and levan to synthesize a composite recovered by a magnetic field. Lectins from Canavalia ensiformis (Con A and Cratylia mollis (Cramoll 1 and Cramoll 1,4 did bind specifically to composite. The magnetic property of derivative favored washing out contaminating proteins and recovery of pure lectins with glucose elution. Cramoll 1 was purified by this affinity binding procedure in two steps instead of a previous three-step protocol with ammonium sulfate fractionation, affinity chromatography on Sephadex G-75, and ion exchange chromatography through a CM-cellulose column.

  20. Ferromagnetic levan composite: an affinity matrix to purify lectin.

    Science.gov (United States)

    Angeli, Renata; da Paz, Nathalia V N; Maciel, Jackeline C; Araújo, Flávia F B; Paiva, Patrícia M G; Calazans, Glícia M T; Valente, Ana Paula; Almeida, Fábio C L; Coelho, Luana C B B; Carvalho, Luiz B; Silva, Maria da Paz C; dos Santos Correia, Maria Tereza

    2009-01-01

    A simple and inexpensive procedure used magnetite and levan to synthesize a composite recovered by a magnetic field. Lectins from Canavalia ensiformis (Con A) and Cratylia mollis (Cramoll 1 and Cramoll 1, 4) did bind specifically to composite. The magnetic property of derivative favored washing out contaminating proteins and recovery of pure lectins with glucose elution. Cramoll 1 was purified by this affinity binding procedure in two steps instead of a previous three-step protocol with ammonium sulfate fractionation, affinity chromatography on Sephadex G-75, and ion exchange chromatography through a CM-cellulose column. PMID:19547713

  1. Affine group representation formalism for four dimensional, Lorentzian, quantum gravity

    CERN Document Server

    Ching-Yi, Chou; Soo, Chopin

    2012-01-01

    The Hamiltonian constraint of 4-dimensional General Relativity is recast explicitly in terms of the Chern--Simons functional and the local volume operator. In conjunction with the algebraic quantization program, application of the affine quantization concept due to Klauder facilitates the construction of solutions to all of the the quantum constraints in the Ashtekar variables and their associated Hilbert space. A physical Hilbert space is constructed for Lorentzian signature gravity with nonzero cosmological constant in the form of unitary, irreducible representations of the affine group.

  2. Affine Hecke algebras associated to Kac-Moody groups

    CERN Document Server

    Garland, H

    1995-01-01

    In this paper we give a geometric construction of Cherednik's double affine Hecke algebra. We construct the algebra as the equivariant K-theory of the Lagrangian subvariety of the cotangent variety of the square of the flag variety of G, the variety being given by the union of the conormal bundles to the G-orbits on \\flag\\times\\flag. This is a generalisation of work of Kazhdan and Lusztig to the Kac-Moody case, and is suitable for describing a certain class of modules for this algebra. In a paper in preparation we will do this, in the case G is affine (Cherednik's case).

  3. Affine diffusions and related processes simulation, theory and applications

    CERN Document Server

    Alfonsi, Aurélien

    2015-01-01

    This book gives an overview of affine diffusions, from Ornstein-Uhlenbeck processes to Wishart processes and it considers some related diffusions such as Wright-Fisher processes. It focuses on different simulation schemes for these processes, especially second-order schemes for the weak error. It also presents some models, mostly in the field of finance, where these methods are relevant and provides some numerical experiments. The book explains the mathematical background to understand affine diffusions and analyze the accuracy of the schemes.  

  4. Combinatorial topology of three-dimensional self-affine tiles

    CERN Document Server

    Bandt, Christoph

    2010-01-01

    We develop tools to study the topology and geometry of self-affine fractals in dimension three and higher. We use the self-affine structure and obtain rather detailed information about the connectedness of interior and boundary sets, and on the dimensions and intersections of boundary sets. As an application, we describe in algebraic terms the polyhedral structure of the six fractal three-dimensional twindragons. Only two of them can be homeomorphic to a ball but even these have faces which are not homeomorphic to a disk.

  5. and as Vertex Operator Extensionsof Dual Affine Algebras

    Science.gov (United States)

    Bowcock, P.; Feigin, B. L.; Semikhatov, A. M.; Taormina, A.

    We discover a realisation of the affine Lie superalgebra and of the exceptional affine superalgebra as vertex operator extensions of two algebras with ``dual'' levels (and an auxiliary level-1 algebra). The duality relation between the levels is . We construct the representation of on a sum of tensor products of , , and modules and decompose it into a direct sum over the spectral flow orbit. This decomposition gives rise to character identities, which we also derive. The extension of the construction to is traced to the properties of embeddings into and their relation with the dual pairs. Conversely, we show how the representations are constructed from representations.

  6. SMOOTH AFFINE SURFACES WITH NON-UNIQUE C*-ACTIONS

    OpenAIRE

    Flenner, Hubert; Kaliman, Shulim; ZAIDENBERG, MIKHAIL

    2008-01-01

    In this paper we complete the classification of effective C*-actions on smooth affine surfaces up to conjugation in the full automorphism group and up to inversion of C*. If a smooth affine surface V admits more than one C*-action then it is known to be Gizatullin i.e., it can be completed by a linear chain of smooth rational curves. In our previous paper we gave a sufficient condition, in terms of the Dolgachev- Pinkham-Demazure (or DPD) presentation, for the uniqueness of a C*-action on a G...

  7. Algebraic volume density property of affine algebraic manifolds

    CERN Document Server

    Kaliman, Shulim

    2009-01-01

    We introduce the notion of algebraic volume density property for affine algebraic manifolds and prove some important basic facts about it, in particular that it implies the volume density property. The main results of the paper are producing two big classes of examples of Stein manifolds with volume density property. One class consists of certain affine modifications of $\\C^n$ equipped with a canonical volume form, the other is the class of all Linear Algebraic Groups equipped with the left invariant volume form.

  8. Extremely high negative electron affinity of diamond via magnesium adsorption

    OpenAIRE

    O'Donnell, Kane M.; Edmonds, Mark T.; Tadich, Anton; Thomsen, Lars; Stacey, Alastair; Schenk, Alex; Pakes, Chris I.; Ley, Lothar

    2015-01-01

    We report large negative electron affinity (NEA) on diamond (100) using magnesium adsorption on a previously oxygen-terminated surface. The measured NEA is up to $(-2.01\\pm0.05)$ eV, the largest reported negative electron affinity to date. Despite the expected close relationship between the surface chemistry of Mg and Li species on oxygen-terminated diamond, we observe differences in the adsorption properties between the two. Most importantly, a high-temperature annealing step is not required...

  9. Double affine Hecke algebras and 2-dimensional local fields

    OpenAIRE

    Kapranov, M.

    1998-01-01

    We give an interpretation of the double affine Hecke algebra of Cherednik as the (suitably regularized) algebra of double cosets of a group G by a subgroup J, extending the well known interpretations of finite and affine Hecke algebras. In this interpretation, G consists of K-points of a split reductive group where K is a 2-dimensional local field such as Q_p((t)) or F_q((t_1))((t_2)), and J is a certain analog of the Iwahori subgroup.

  10. Kinetic controlled affinity labeling of target enzyme with thioester chemistry.

    Science.gov (United States)

    Tomohiro, Takenori; Nakabayashi, Masahiro; Sugita, Yuka; Morimoto, Shota

    2016-08-01

    High specificity has been an important feature in affinity labeling for target profiling. Especially, to label targets via rapidly progressing reactions with consumption of ligand (probe), high specificity of reaction with common functional groups of target protein should be achieved without reactions with similar groups of non-target proteins. Herein, we demonstrate the kinetic controlled affinity labeling of acyl CoA synthetase using a fatty acid analogue containing a phenylthioester linkage. High specificity was attained by accelerating the labeling rate in the binding pocket. This approach could be useful for profiling a series of target enzymes and transporters in signal transduction pathways. PMID:27298000

  11. The Phenomenon of «Deep Water» Influx from the Earth's Interior and its Role in the Development of the Earth

    Directory of Open Access Journals (Sweden)

    A. I. Tikhonov

    2014-12-01

    Full Text Available The phenomenon of extensive permanent influx of the «deep-water» to the hydrosphere of the Earth characterized by a high content of various chemical components, including mineral and toxic elements of deep origin is considered. Results of analysis of large amount of experimental data suggest that «deep-water» is a source of formation and permanent supplement of the ocean water with stable salinity, chemical and isotopic composition, and the formation of various mineralized water deposits. «Deep-water» can cause formation of substandard water clusters within the underground fresh water fields, affecting their ecological quality.

  12. Thermal and mass implications of magmatic evolution in the Lassen volcanic region, California, and minimum constraints on basalt influx to the lower crust

    Science.gov (United States)

    Guffanti, M.; Clynne, M.A.; Muffler, L.J.P.

    1996-01-01

    We have analyzed the heat and mass demands of a petrologic model of basaltdriven magmatic evolution in which variously fractionated mafic magmas mix with silicic partial melts of the lower crust. We have formulated steady state heat budgets for two volcanically distinct areas in the Lassen region: the large, late Quaternary, intermediate to silicic Lassen volcanic center and the nearby, coeval, less evolved Caribou volcanic field. At Caribou volcanic field, heat provided by cooling and fractional crystallization of 52 km3 of basalt is more than sufficient to produce 10 km3 of rhyolitic melt by partial melting of lower crust. Net heat added by basalt intrusion at Caribou volcanic field is equivalent to an increase in lower crustal heat flow of ???7 mW m-2, indicating that the field is not a major crustal thermal anomaly. Addition of cumulates from fractionation is offset by removal of erupted partial melts. A minimum basalt influx of 0.3 km3 (km2 Ma)-1 is needed to supply Caribou volcanic field. Our methodology does not fully account for an influx of basalt that remains in the crust as derivative intrusives. On the basis of comparison to deep heat flow, the input of basalt could be ???3 to 7 times the amount we calculate. At Lassen volcanic center, at least 203 km3 of mantle-derived basalt is needed to produce 141 km3 of partial melt and drive the volcanic system. Partial melting mobilizes lower crustal material, augmenting the magmatic volume available for eruption at Lassen volcanic center; thus the erupted volume of 215 km3 exceeds the calculated basalt input of 203 km3. The minimum basalt input of 1.6 km3 (km2 Ma)-1 is >5 times the minimum influx to the Caribou volcanic field. Basalt influx high enough to sustain considerable partial melting, coupled with locally high extension rate, is a crucial factor in development of Lassen volcanic center; in contrast. Caribou volcanic field has failed to develop into a large silicic center primarily because basalt supply

  13. Effects of the Ca agonist Bay K8644 on 45Ca influx and net Ca uptake into rabbit aortic smooth muscle

    International Nuclear Information System (INIS)

    The authors examined the effects of Bay K8644 and external K+ on isolated rings of rabbit aorta. Previous evidence has suggested that the Ca channel agonist, Bay K8644, preferentially opens the potential-sensitive Ca2+ channels (PSCs) rather than receptor-operated Ca2+ channels (ROCs). Bay K8644 stimulated 45Ca influx, net Ca gain and contractile tension were measured as a function of extracellular K+ concentration. The data are explained in terms of a calcium entry model consisting of membrane Ca2+ channels in series with a subplasmalemmal barrier consisting of superficial sarcoplasmic reticulum (SR). (Auth.)

  14. Syndromic surveillance of epidemic-prone diseases in response to an influx of migrants from North Africa to Italy, May to October 2011.

    Science.gov (United States)

    Riccardo, F; Napoli, C; Bella, A; Rizzo, C; Rota, M C; Dente, M G; De Santis, S; Declich, S

    2011-01-01

    Following civil unrest in North Africa early in 2011, there was a large influx of migrants in Italy. A syndromic surveillance system was set up in April to monitor the health of this migrant population and respond rapidly to any health emergency. In the first six months, the system produced 67 alerts across all syndromes monitored and four alarms. There were no health emergencies, however, indicating that this migration flow was not associated with an increased risk of communicable disease transmission in Italy. PMID:22115045

  15. Student Engagement and Neoliberalism: Mapping an Elective Affinity

    Science.gov (United States)

    Zepke, Nick

    2015-01-01

    The purpose of this article is to argue that student engagement, an important area for research about learning and teaching in formal higher education, has an elective affinity with neoliberalism, a hegemonic ideology in many countries of the developed world. The paper first surveys an extensive research literature examining student engagement and…

  16. Several Affinity Tags Commonly Used in Chromatographic Purification

    Directory of Open Access Journals (Sweden)

    Xinyu Zhao

    2013-01-01

    Full Text Available Affinity tags have become powerful tools from basic biological research to structural and functional proteomics. They were widely used to facilitate the purification and detection of proteins of interest, as well as the separation of protein complexes. Here, we mainly discuss the benefits and drawbacks of several affinity or epitope tags frequently used, including hexahistidine tag, FLAG tag, Strep II tag, streptavidin-binding peptide (SBP tag, calmodulin-binding peptide (CBP, glutathione S-transferase (GST, maltose-binding protein (MBP, S-tag, HA tag, and c-Myc tag. In some cases, a large-size affinity tag, such as GST or MBP, can significantly impact on the structure and biological activity of the fusion partner protein. So it is usually necessary to excise the tag by protease. The most commonly used endopeptidases are enterokinase, factor Xa, thrombin, tobacco etch virus, and human rhinovirus 3C protease. The proteolysis features of these proteases are described in order to provide a general guidance on the proteolytic removal of the affinity tags.

  17. Smooth surfaces from bilinear patches: Discrete affine minimal surfaces

    KAUST Repository

    Käferböck, Florian

    2013-06-01

    Motivated by applications in freeform architecture, we study surfaces which are composed of smoothly joined bilinear patches. These surfaces turn out to be discrete versions of negatively curved affine minimal surfaces and share many properties with their classical smooth counterparts. We present computational design approaches and study special cases which should be interesting for the architectural application. 2013 Elsevier B.V.

  18. General $L\\sb p$ affine isoperimetric inequalities

    OpenAIRE

    Haberl, Christoph; Schuster, Franz E.

    2009-01-01

    Sharp $L\\sb p$ affine isoperimetric inequalities are established for the entire class of $L\\sb p$ projection bodies and the entire class of $L\\sb p$ centroid bodies. These new inequalities strengthen the $L\\sb p$ Petty projection and the $L\\sb p$ Busemann–Petty centroid inequality.

  19. PP-waves with torsion and metric-affine gravity

    OpenAIRE

    Pasic, Vedad; Vassiliev, Dmitri

    2005-01-01

    A classical pp-wave is a 4-dimensional Lorentzian spacetime which admits a nonvanishing parallel spinor field; here the connection is assumed to be Levi-Civita. We generalise this definition to metric compatible spacetimes with torsion and describe basic properties of such spacetimes. We use our generalised pp-waves for constructing new explicit vacuum solutions of quadratic metric-affine gravity.

  20. Affinity purification of polysaccharide degrading enzymes with crosslinked substrates.

    NARCIS (Netherlands)

    Rozie, H.J.

    1992-01-01

    The aim of this work was to find economically favourable, affinity based, purification methods for several polysaccharide splitting bulk enzymes. The framework in which this study is done is described in Chapter 1.Chapter 2 describes the adsorption of endo-polygalacturonase (endoPG) from a commercia

  1. Affine group formulation of the Standard Model coupled to gravity

    CERN Document Server

    Chou, Ching-Yi; Soo, Chopin

    2013-01-01

    Using the affine group formalism, we perform a nonperturbative quantization leading to the construction of elements of a physical Hilbert space for full, Lorentzian quantum gravity coupled to the Standard Model in four spacetime dimensions. This paper constitutes a first step toward understanding the phenomenology of quantum gravitational effects stemming from a consistent treatment of minimal couplings to matter.

  2. Self-Affine Sets with Positive Lebesgue Measure

    NARCIS (Netherlands)

    Dajani, Karma; Jiang, Kan; Kempton, Tom

    2014-01-01

    Using techniques introduced by C. G ̈unt ̈urk, we prove that the attractors of a family of overlapping self-affine iterated function systems contain a neighbourhood of zero for all parameters in a certain range. This corresponds to giving conditions under which a single sequence may serve as a ‘simu

  3. An invariant interest point detector under image affine transformation

    Institute of Scientific and Technical Information of China (English)

    林睿; 黄海波; 孙荣川; 孙立宁

    2015-01-01

    For vision-based mobile robot navigation, images of the same scene may undergo a general affine transformation in the case of significant viewpoint changes. So, a novel method for detecting affine invariant interest points is proposed to obtain the invariant local features, which is coined polynomial local orientation tensor (PLOT). The new detector is based on image local orientation tensor that is constructed from the polynomial expansion of image signal. Firstly, the properties of local orientation tensor of PLOT are analyzed, and a suitable tuning parameter of local orientation tensor is chosen so as to extract invariant features. The initial interest points are detected by local maxima search for the smaller eigenvalues of the orientation tensor. Then, an iterative procedure is used to allow the initial interest points to converge to affine invariant interest points and regions. The performances of this detector are evaluated on the repeatability criteria and recall versus 1-precision graphs, and then are compared with other existing approaches. Experimental results for PLOT show strong performance under affine transformation in the real-world conditions.

  4. Canonical bases and affine Hecke algebras of type B

    CERN Document Server

    Varagnolo, Michela

    2009-01-01

    We prove a series of conjectures of Enomoto and Kashiwara on canonical bases and branching rules of affine Hecke algebras of type B. The main ingredient of the proof is a new graded Ext-algebra associated with quiver with involutions that we compute explicitly.

  5. Reconfigurable Control of Input Affine Nonlinear Systems under Actuator Fault

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Galeazzi, Roberto

    2015-01-01

    This paper proposes a fault tolerant control method for input-affine nonlinear systems using a nonlinear reconfiguration block (RB). The basic idea of the method is to insert the RB between the plant and the nominal controller such that fault tolerance is achieved without re-designing the nominal...

  6. Higher-order momentum distributions and locally affine LDDMM registration

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Nielsen, Mads; Darkner, Sune;

    2013-01-01

    description of affine transformations and subsequent compact description of non-translational movement in a globally nonrigid deformation. The resulting representation contains directly interpretable information from both mathematical and modeling perspectives. We develop the mathematical construction...... higher-order momenta lead to natural modeling of articulated movement, and the method promises to be useful for quantifying ventricle expansion and progressing atrophy during Alzheimer's disease....

  7. Toward an Affinity Space Methodology: Considerations for Literacy Research

    Science.gov (United States)

    Lammers, Jayne C.; Curwood, Jen Scott; Magnifico, Alecia Marie

    2012-01-01

    As researchers seek to make sense of young people's online literacy practices and participation, questions of methodology are important to consider. In our work to understand the culture of physical, virtual and blended spheres that adolescents inhabit, we find it necessary to expand Gee's (2004) notion of affinity spaces. In this article, we draw…

  8. Native Elution of Yeast Protein Complexes Obtained by Affinity Capture.

    Science.gov (United States)

    LaCava, John; Fernandez-Martinez, Javier; Rout, Michael P

    2016-01-01

    This protocol describes two options for the native (nondenaturing) elution of protein complexes obtained by affinity capture. The first approach involves the elution of complexes purified through a tag that includes a human rhinovirus 3C protease (PreScission protease) cleavage site sequence between the protein of interest and the tag. Incubation with the protease cleaves immobilized complexes from the affinity medium. The second approach involves the release of protein A-tagged protein complexes using a competitive elution reagent called PEGylOx. The degree of purity of the native assemblies eluted is sample dependent and strongly influenced by the affinity capture. It should be noted that the efficiency of native elution is commonly lower than that of elution by a denaturing agent (e.g., SDS) and the release of the complex will be limited by the activity of the protease or the inhibition constant (Ki) of the competitive release agent. However, an advantage of native release is that some nonspecifically bound materials tend to stay adsorbed to the affinity medium, providing an eluted fraction of higher purity. Finally, keep in mind that the presence of the protease or elution peptide could potentially affect downstream applications; thus, their removal should be considered. PMID:27371597

  9. Properties of an affine transport equation and its holonomy

    Science.gov (United States)

    Vines, Justin; Nichols, David A.

    2016-10-01

    An affine transport equation was used recently to study properties of angular momentum and gravitational-wave memory effects in general relativity. In this paper, we investigate local properties of this transport equation in greater detail. Associated with this transport equation is a map between the tangent spaces at two points on a curve. This map consists of a homogeneous (linear) part given by the parallel transport map along the curve plus an inhomogeneous part, which is related to the development of a curve in a manifold into an affine tangent space. For closed curves, the affine transport equation defines a "generalized holonomy" that takes the form of an affine map on the tangent space. We explore the local properties of this generalized holonomy by using covariant bitensor methods to compute the generalized holonomy around geodesic polygon loops. We focus on triangles and "parallelogramoids" with sides formed from geodesic segments. For small loops, we recover the well-known result for the leading-order linear holonomy (˜ Riemann × area), and we derive the leading-order inhomogeneous part of the generalized holonomy (˜ Riemann × area^{3/2}). Our bitensor methods let us naturally compute higher-order corrections to these leading results. These corrections reveal the form of the finite-size effects that enter into the holonomy for larger loops; they could also provide quantitative errors on the leading-order results for finite loops.

  10. On global asymptotic controllability of planar affine nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    SUN Yimin; GUO Lei

    2005-01-01

    In this paper, we present a necessary and sufficient condition for globally asymptotic controllability of the general planar affine nonlinear systems with single-input.This result is obtained by introducing a new method in the analysis, which is based on the use of some basic results in planar topology and in the geometric theory of ordinary differential equations.

  11. "The Hunger Games": Literature, Literacy, and Online Affinity Spaces

    Science.gov (United States)

    Curwood, Jen Scott

    2013-01-01

    This article examines adolescent literacy practices related to "The Hunger Games," a young adult novel and the first of a trilogy. By focusing on the interaction of social identities, discourses, and media paratexts within an online affinity space, this ethnographic study offers insight into how young adults engage with contemporary…

  12. Electrochemical affinity biosensors for detection of mycotoxins: A review.

    Science.gov (United States)

    Vidal, Juan C; Bonel, Laura; Ezquerra, Alba; Hernández, Susana; Bertolín, Juan R; Cubel, Carlota; Castillo, Juan R

    2013-11-15

    This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago.

  13. Combinatorial Vector Fields for Piecewise Affine Control Systems

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Larsen, Jesper Abildgaard

    2008-01-01

    This paper is intended to be a continuation of Habets and van Schuppen (2004) and Habets, Collins and van Schuppen (2006), which address the control problem for piecewise-affine systems on an arbitrary polytope or a family of these. Our work deals with the underlying combinatorics of the underlyi...

  14. Affine Toda Solitons and Systems of Calogero-Moser Type

    OpenAIRE

    Braden, H. W.; Hone, Andrew N. W.

    1996-01-01

    The solitons of affine Toda field theory are related to the spin-generalised Ruijsenaars-Schneider (or relativistic Calogero-Moser) models. This provides the sought after extension of the correspondence between the sine-Gordon solitons and the Ruijsenaars-Schneider model.

  15. Prediction of peptide bonding affinity: kernel methods for nonlinear modeling

    CERN Document Server

    Bergeron, Charles; Sundling, C Matthew; Krein, Michael; Katt, Bill; Sukumar, Nagamani; Breneman, Curt M; Bennett, Kristin P

    2011-01-01

    This paper presents regression models obtained from a process of blind prediction of peptide binding affinity from provided descriptors for several distinct datasets as part of the 2006 Comparative Evaluation of Prediction Algorithms (COEPRA) contest. This paper finds that kernel partial least squares, a nonlinear partial least squares (PLS) algorithm, outperforms PLS, and that the incorporation of transferable atom equivalent features improves predictive capability.

  16. Linear independence measure of logarithms over affine groups

    OpenAIRE

    Huicochea, Mario

    2015-01-01

    Linear forms in logarithms over connected commutative algebraic groups over the algebraic numbers field have been studied widely. However, the theory of linear forms in logarithms over noncommutative algebraic groups have not been developed as the one of the commutative algebraic groups and in this paper we start studying linear forms in logarithms over affine groups.

  17. Demazure modules and vertex models the affine sl(2) case

    CERN Document Server

    Foda, O E; Okado, M; Foda, Omar; Misra, Kailash C; Okado, Masato

    1996-01-01

    We characterize, in the case of affine sl(2), the crystal base of the Demazure module E_w(\\La) in terms of extended Young diagrams or paths for any dominant integral weight \\La and Weyl group element w. Its character is evaluated via two expressions, 'bosonic' and 'fermionic'.

  18. Demazure modules and vertex models: the affine sl(2) case

    OpenAIRE

    Foda, Omar; Misra, Kailash C.; Okado, Masato

    1996-01-01

    We characterize, in the case of affine sl(2), the crystal base of the Demazure module E_w(\\La) in terms of extended Young diagrams or paths for any dominant integral weight \\La and Weyl group element w. Its character is evaluated via two expressions, 'bosonic' and 'fermionic'.

  19. Novel trends in affinity biosensors: current challenges and perspectives

    International Nuclear Information System (INIS)

    Molecular biorecognition processes facilitate physical and biochemical interactions between molecules in all crucial metabolic pathways. Perhaps the target analyte and the biorecognition element interactions have the most impactful use in biosensing applications. Traditional analytical sensing systems offer excellent biorecognition elements with the ability to detect and determine the presence of analytes. High affinity antibodies and DNA play an important role in the development of affinity biosensors based on electrochemical, optical and mass sensitive approaches. Advancements in this area routinely employ labels, label free, nanoparticles, multifunctional matrices, carbon nanotubes and other methods to meet the requirements of its own application. However, despite increasing affinity ceilings for conventional biosensors, the field draws back in meeting specifically important demands, such as long-term stability, ultrasensitivity, rapid detection, extreme selectivity, strong biological base, calibration, in vivo measurements, regeneration, satisfactory performance and ease of production. Nevertheless, recent efforts through this line have produced novel high-tech nanosensing systems such as ‘aptamers’ and ‘phages’ which exhibit high-throughput sensing. Aptamers and phages are powerful tools that excel over antibodies in sensibility, stability, multi-detection, in vivo measurements and regeneration. Phages are superior in stability, screening for affinity-based target molecules ranging from small to proteins and even cells, and easy production. In this review, we focus mainly on recent developments in affinity-based biosensors such as immunosensors, DNA sensors, emphasizing aptasensors and phage-based biosensors basing on novel electrochemical, optical and mass sensitive detection techniques. We also address enzyme inhibition-based biosensors and the current problems associated with the above sensors and their future perspectives. (topical review)

  20. Influx of testosterone-binding globulin (TeBG) and TeBG-bound sex steroid hormones into rat testis and prostate

    Energy Technology Data Exchange (ETDEWEB)

    Sakiyama, R.; Pardridge, W.M.; Musto, N.A.

    1988-07-01

    The availability of testosterone and estradiol to Sertoli and prostate cells is dependent upon 1) the permeability properties of the blood-tubular barrier (BTB) of the testis or prostate cell membrane, and 2) sex steroid binding to plasma proteins, such as albumin or testosterone-binding globulin (TeBG). Sex steroid influx into these tissues was studied after in vivo arterial bolus injections of (/sup 3/H)testosterone or (/sup 3/H)estradiol in anesthetized rats. Both testosterone and estradiol were readily cleared across the BTB or prostate cell membrane in the absence of plasma proteins and in the presence of human pregnancy serum, in which testosterone or estradiol are 80-95% distributed to TeBG. The extravascular extraction of (/sup 3/H)TeBG across the BTB or prostate plasma membrane (73 +/- 2% (+/- SE) and 92 +/- 9%, respectively) was significantly greater than extraction of (/sup 3/H)albumin or other plasma space markers and indicative of a rapid first pass clearance of TeBG by Sertoli or prostate cells. In summary, these studies indicate that 1) testosterone and estradiol are readily cleared by Sertoli and prostate cells; 2) albumin- and TeBG-bound sex steroids represent the major circulating pool of bioavailable hormone for testis or prostate; and 3) the TeBG-sex steroid complex may be nearly completely available for influx through the BTB or prostate plasma membrane.

  1. Influx-Operated Ca2+ Entry via PKD2-L1 and PKD1-L3 Channels Facilitates Sensory Responses to Polymodal Transient Stimuli

    Directory of Open Access Journals (Sweden)

    Mingfeng Hu

    2015-10-01

    Full Text Available The polycystic TRP subfamily member PKD2-L1, in complex with PKD1-L3, is involved in physiological responses to diverse stimuli. A major challenge to understanding whether and how PKD2-L1/PKD1-L3 acts as a bona fide molecular transducer is that recombinant channels usually respond with small or undetectable currents. Here, we discover a type of Ca2+ influx-operated Ca2+ entry (ICE that generates pronounced Ca2+ spikes. Triggered by rapid onset/offset of Ca2+, voltage, or acid stimuli, Ca2+-dependent activation amplifies a small Ca2+ influx via the channel. Ca2+ concurrently drives a self-limiting negative feedback (Ca2+-dependent inactivation that is regulated by the Ca2+-binding EF hands of PKD2-L1. Our results suggest a biphasic ICE with opposite Ca2+ feedback regulation that facilitates sensory responses to multimodal transient stimuli. We suggest that such a mechanism may also occur for other sensory modalities and other Ca2+ channels.

  2. Cadmium sorption, influx, and efflux at the mesophyll layer of leaves from ecotypes of the Zn/Cd hyperaccumulator Thlaspi caerulescens.

    Science.gov (United States)

    Ebbs, Stephen D; Zambrano, M Clemencia; Spiller, Shawna M; Newville, Matthew

    2009-01-01

    Differential sorption and transport characteristics of the leaf mesophyll layer of the Prayon and Ganges ecotypes of the hyperaccumulator Thlaspi caerulescens were examined. (109)Cd influx and efflux experiments were conducted with leaf sections, and X-ray absorption near edge structure (XANES) data were collected from leaves as a general comparison of in vivo cadmium (Cd) coordination. There were modest differences in cell wall sorption of Cd between ecotypes. There were obvious differences in time- and concentration-dependent Cd influx, including a greater V(MAX) for Prayon but a lower K(M) for Ganges for concentration-dependent Cd uptake and a notably greater Cd uptake by Ganges leaf sections at 1000 microm Cd. Leaf sections of Prayon had a greater Cd efflux than Ganges. The XANES spectra from the two ecotypes suggested differences in Cd coordination. The fundamental differences observed between the two ecotypes may reflect differential activity and/or expression of plasma membrane and tonoplast transporters. More detailed study of these transporters and the in vivo coordination of Cd are needed to determine the contribution of these processes to metal homeostasis and tolerance. PMID:19054336

  3. Cadmium sorption, influx, and efflux at the mesophyll layer of leaves from ecotypes of the Zn/Cd hyperaccumulator Thlaspi caerulescens

    Energy Technology Data Exchange (ETDEWEB)

    Ebbs, S.D.; Zambrano, M.C.; Spiller, S.M.; Newville, M. (SIU); (UC)

    2009-01-23

    Differential sorption and transport characteristics of the leaf mesophyll layer of the Prayon and Ganges ecotypes of the hyperaccumulator Thlaspi caerulescens were examined. {sup 109}Cd influx and efflux experiments were conducted with leaf sections, and X-ray absorption near edge structure (XANES) data were collected from leaves as a general comparison of in vivo cadmium (Cd) coordination. There were modest differences in cell wall sorption of Cd between ecotypes. There were obvious differences in time- and concentration-dependent Cd influx, including a greater V{sub MAX} for Prayon but a lower K{sub M} for Ganges for concentration-dependent Cd uptake and a notably greater Cd uptake by Ganges leaf sections at 1000 {micro}m Cd. Leaf sections of Prayon had a greater Cd efflux than Ganges. The XANES spectra from the two ecotypes suggested differences in Cd coordination. The fundamental differences observed between the two ecotypes may reflect differential activity and/or expression of plasma membrane and tonoplast transporters. More detailed study of these transporters and the in vivo coordination of Cd are needed to determine the contribution of these processes to metal homeostasis and tolerance.

  4. A comparative study of two clerodane diterpenes from Baccharis trimera (Less.) DC. on the influx and mobilization of intracellular calcium in rat cardiomyocytes.

    Science.gov (United States)

    Garcia, Francisca Adilfa de Oliveira; Tanae, Mirtes Midori; Torres, Luce Maria Brandão; Lapa, Antônio José; de Lima-Landman, Maria Teresa Riggio; Souccar, Caden

    2014-01-01

    Baccharis trimera (Less.) D.C. (Asteraceae) is a medicinal species native to South America and used in Brazilian folk medicine to treat gastrointestinal and liver diseases, kidney disorders and diabetes. The aqueous extract (AE) of the aerial parts of this species presented two mainly constituents: the ent-clerodane diterpene (Fig. 1) and the neo-clerodane diterpene (Fig. 2). The objective of this work was to study their activities on the blockade of Ca(2+)-induced contractions in KCL-depolarized rat portal vein preparations, and on the influx and mobilization of cytosolic calcium in rat cardiomyocytes by fluorescence measurements. The results showed that both the neo- and the ent-clerodane diterpenes reduced the maximal contractions induced by CaCl2, in KCl depolarized rat portal vein preparations, without modifying the EC50. The data on the concentration of cytosolic calcium ([Ca(2+)]c) showed that, while the neo-clerodane diterpene stimulates the mobilization of [Ca(2+)]c in rat cardiomyocytes, this effect was not observed with the ent-clerodane diterpene. On the other hand, the influx of calcium was not altered by the neo-clerodane diterpene, but was reduced in the presence of the ent-clerodane diterpene, indicating that this compound induces a blockade of the voltage-dependent calcium channels.

  5. A novel affinity purification method to isolate peptide specific antibodies

    DEFF Research Database (Denmark)

    Karlsen, Alan E; Lernmark, A; Kofod, Hans;

    1990-01-01

    with the beads and after a wash step the bound antibodies were eluted in 1 M acetic acid. The eluted material was composed predominantly of intact immunoglobulin as evidenced by the presence of heavy and light chain bands in SDS-PAGE. The eluted antibodies were peptide specific in ELISA and bound only to intact......Site-specific, high affinity polyclonal antisera are effectively and successfully produced by immunizing rabbits with synthetic peptides. The use of these antisera in subsequent immune analysis is often limited because of non-specific binding. We describe a new and simple method to effectively...... affinity-purify anti-peptide antibodies. To test our system, rabbits were immunized with model peptides representing sequences of the putative rabbit growth hormone receptor and several HLA-DQ beta-chain molecules. Polystyrene plastic beads were coated with peptides. Immune serum was incubated...

  6. Telonemia, a new protist phylum with affinity to chromist lineages

    DEFF Research Database (Denmark)

    Shalchian-Tabrizi, K.; Eikrem, W.; Klaveness, D.;

    2006-01-01

    , such as the alveolates and heterokonts. Using the same approach on coastal samples, we have identified a novel group of protist small subunit (SSU) rDNA sequences that do not correspond to any phylogenetic group previously identified. Comparison with other sequences obtained from cultures of heterotrophic protists...... showed that the environmental sequences grouped together with Telonema, a genus known since 1913 but of uncertain taxonomic affinity. Phylogenetic analyses using four genes (SSU, Hsp90, alpha-tubulin and beta-tubulin), and accounting for gamma- and covarion-distributed substitution rates, revealed...... Telonema as a distinct group of species branching off close to chromist lineages. Consistent with these gene trees, Telonema possesses ultrastructures revealing both the distinctness of the group and the evolutionary affinity to chromist groups. Altogether, the data suggest that Telonema constitutes a new...

  7. Craniomandibular morphology and phylogenetic affinities of panthera atrox

    DEFF Research Database (Denmark)

    Christiansen, Per; Harris, J.M.

    2009-01-01

    The great North American Pleistocene pantherine felid Panthera atrox has had a turbulent phylogenetic history, and has been claimed to show affinities to both the jaguar and the tiger; currently, it is most often regarded as a subspecies of the extant lion. The cranial, mandibular, and dental...... morphology of Panthera atrox was compared with those of extant lions, jaguars, and tigers using bivariate, multivariate, and shape analyses. Results indicate that the skull of Panthera atrox shows lion affinities, but also deviates from lions in numerous aspects. Mandibular morphology is more similar...... to jaguars and tigers and, as with cranial morphology, the mandible shows a number of traits not present among extant pantherines. Multivariate analyses grouped Panthera atrox separately from other pantherines. Panthera atrox was no lion, and cannot be assigned to any of the extant pantherines...

  8. Evolution based on chromosome affinity from a network perspective

    Science.gov (United States)

    Monteiro, R. L. S.; Fontoura, J. R. A.; Carneiro, T. K. G.; Moret, M. A.; Pereira, H. B. B.

    2014-06-01

    Recent studies have focused on models to simulate the complex phenomenon of evolution of species. Several studies have been performed with theoretical models based on Darwin's theories to associate them with the actual evolution of species. However, none of the existing models include the affinity between individuals using network properties. In this paper, we present a new model based on the concept of affinity. The model is used to simulate the evolution of species in an ecosystem composed of individuals and their relationships. We propose an evolutive algorithm that incorporates the degree centrality and efficiency network properties to perform the crossover process and to obtain the network topology objective, respectively. Using a real network as a starting point, we simulate its evolution and compare its results with the results of 5788 computer-generated networks.

  9. The affine theory of gravitation and electromagnetism I

    CERN Document Server

    Poplawski, N J

    2006-01-01

    The affine variational principle of Eddington generates the Einstein field equations of general relativity in vacuum with a non-zero cosmological constant. We generalize this principle to include electromagnetism, obtaining the Einstein--Maxwell field equations and the Lorentz equation of motion. We vary the action with respect to the quantities that appear in the definition of the electromagnetic covariant derivative: the affine (nonsymmetric) connection and the electromagnetic potential, while the Lagrangian density is taken to be the square root of the determinant of a linear combination of the symmetrized Ricci tensor and the electromagnetic field tensor. This construction generates a symmetric metric tensor and a connection with torsion that depends only on the torsion vector. The whole formulation is valid only for very weak electromagnetic fields on the order of the magnetic field in interstellar space.

  10. Determination of NO chemical affinities of benzyl nitrite in acetonitrile

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Xiaoqing ZHU; Jinpei CHENG

    2008-01-01

    There is an increasing interest in the study of NO chemical affinities of organic nitrites, for the bio-logical and physiological effects of organic nitrites seem to be due to their ability to release NO. In this paper, NO chemical affinities of ten substituted benzyl nitrites were determined by titration calorimetry combined with a ther-modynamic cycle in acetonitrile solution. The results show that ΔHhet(O-NO)s of benzyl nitrites are substan-tially larger than the corresponding ΔHhomo(O-NO)s, suggesting that these O-nitroso compounds much more easily release NO radicals by the O-NO bond homolytic cleavage. It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.

  11. A NOVEL METAL CHELATE AFFINITY ADSORBENT FOR PROTEIN UPTAKE

    Institute of Scientific and Technical Information of China (English)

    WANGYongjian; BAIShu; 等

    2001-01-01

    In this article,a spherical chitosan gel crosslinked by epichlorohydrin was prepared.It was then loaded with copper ions to produce a metal chelate affinity adsorbent for protein.The uptake of bovine serum albumin(BSA)by the affinity adsorbent was investigated.and the adsorption capacity for BSA as high as 40mg/g-wet beads was observed.The adsorption equilibrium data was well correlated by the Langmuir equation.The adsorption was considerably affected by pH.In additio.The amount of BSA adsorbed onto the beads decreased with the increasing of aqueous phase ionic strength,so adsorbed BAS can be desorbed by adjusting pH orionic strength of the solution.

  12. On purely transmitting defects in affine Toda field theory

    CERN Document Server

    Corrigan, E

    2007-01-01

    Affine Toda field theories with a purely transmitting integrable defect are considered and the model based on a_2 is analysed in detail. After providing a complete characterization of the problem in a classical framework, a suitable quantum transmission matrix, able to describe the interaction between an integrable defect and solitons, is found. Two independent paths are taken to reach the result. One is an investigation of the triangle equations using the S-matrix for the imaginary coupling bulk affine Toda field theories proposed by Hollowood, and the other uses a functional integral approach together with a bootstrap procedure. Evidence to support the results is collected in various ways: for instance, through the calculation of the transmission factors for the lightest breathers. While previous discoveries within the sine-Gordon model motivated this study, there are several new phenomena displayed in the a_2 model including intriguing disparities between the classical and the quantum pictures. For example...

  13. An angular momentum conserving Affine-Particle-In-Cell method

    CERN Document Server

    Jiang, Chenfanfu; Teran, Joseph

    2016-01-01

    We present a new technique for transferring momentum and velocity between particles and grid with Particle-In-Cell (PIC) calculations which we call Affine-Particle-In-Cell (APIC). APIC represents particle velocities as locally affine, rather than locally constant as in traditional PIC. We show that this representation allows APIC to conserve linear and angular momentum across transfers while also dramatically reducing numerical diffusion usually associated with PIC. Notably, conservation is achieved with lumped mass, as opposed to the more commonly used Fluid Implicit Particle (FLIP) transfers which require a 'full' mass matrix for exact conservation. Furthermore, unlike FLIP, APIC retains a filtering property of the original PIC and thus does not accumulate velocity modes on particles as FLIP does. In particular, we demonstrate that APIC does not experience velocity instabilities that are characteristic of FLIP in a number of Material Point Method (MPM) hyperelasticity calculations. Lastly, we demonstrate th...

  14. Quantized Affine Lie Algebras and Diagonalization of Braid Generators

    CERN Document Server

    Gould, M D; Gould, Mark D.; Zhang, Yao-Zhong

    1994-01-01

    Let $U_q(\\hat{\\cal G})$ be a quantized affine Lie algebra. It is proven that the universal R-matrix $R$ of $U_q(\\hat{\\cal G})$ satisfies the celebrated conjugation relation $R^\\dagger=TR$ with $T$ the usual twist map. As applications, braid generators are shown to be diagonalizable on arbitrary tensor product modules of integrable irreducible highest weight $U_q(\\hat{\\cal G})$-module and a spectral decomposition formula for the braid generators is obtained which is the generalization of Reshetikhin's and Gould's forms to the present affine case. Casimir invariants are constructed and their eigenvalues computed by means of the spectral decomposition formula. As a by-product, an interesting identity is found.

  15. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  16. Algorithm-Architecture Affinity - Parallelism Changes the Picture

    DEFF Research Database (Denmark)

    Abildgren, Rasmus; Šaramentovas, Aleksandras; Ruzgys, Paulius;

    Reducing the time-to-market factor is a challenge for many embedded systems designers. In that respect, hardwaresoftware partitioning is a key issue which has been studied during the last two decades. In this paper we present an extension to recent works dealing with metrics for guiding...... the hardware-software partitioning step. This extension builds upon and complement our own work with metrics in the Design Trotter project, and is combined with the affinity metric approach. We show that the proposed extension improves the original affinity metric in terms of parallelism detection, and thus...... can help system designers to make wiser hardware-software partitioning decisions, which in turn reduces the time-to-market factor....

  17. The Weyl-Cartan Space Problem in Purely Affine Theory

    Science.gov (United States)

    von Borzeszkowski, Horst-Heino; Treder, Hans-Jürgen

    1997-04-01

    According to Poincaré, only the ``epistemological sum of geometry and physics is measurable". Of course, there are requirements of measurement to be imposed on geometry because otherwise the theory resting on this geometry cannot be physically interpreted. In particular, the Weyl--Cartan space problem must be solved, i.e., it must be guaranteed that the comparison of distances is compatible with the Levi-Civita transport. In the present paper, we discuss these requirements of measurement and show that in the (purely affine) Einstein-Schrödinger unified field theory the solution of the Weyl-Cartan space problem simultaneously determines the matter via Einstein's equations. Here the affine field $\\Gamma^ikl$ represents Poincaré's sum, and the solution of the space problem means its splitting in a metrical space and in matter fields, where the latter are given by the torsion tensor $\\Gamma^i_{[kl]}$.

  18. Improved Energy-Momentum Currents in Metric-Affine Spacetime

    CERN Document Server

    Hecht, R D; McCrea, J D; Mielke, E W; Ne'eman, Yuval; Hecht, Ralf; Hehl, Friedrich W.; Mielke, Eckehard W.; Ne'eman, Yuval

    1992-01-01

    In Minkowski spacetime it is well-known that the canonical energy-momentum current is involved in the construction of the globally conserved currents of energy-momentum and total angular momentum. For the construction of conserved currents corresponding to (approximate) scale and proper conformal symmetries, however, an improved energy-momentum current is needed. By extending the Minkowskian framework to a genuine metric-affine spacetime, we find that the affine Noether identities and the conformal Killing equations enforce this improvement in a rather natural way. So far, no gravitational dynamics is involved in our construction. The resulting dilation and proper conformal currents are conserved provided the trace of the energy-momentum current satisfies a (mild) scaling relation or even vanishes.

  19. Nonspectrality of Certain Self-Affine Measures on ℝ3

    Directory of Open Access Journals (Sweden)

    Gui-Bao Gao

    2014-01-01

    Full Text Available We will determine the nonspectrality of self-affine measure μB,D corresponding to B=diag[p1,p2,p3]  (p1∈(2ℤ+1∖{±1}, p2∈2ℤ∖{0}, and D={0,e1,e2,e3} in the space ℝ3 is supported on T(B,D, where e1,  e2, and e3 are the standard basis of unit column vectors in ℝ3, and there exist at most 4 mutually orthogonal exponential functions in L2(μB,D, where the number 4 is the best. This generalizes the known results on the spectrality of self-affine measures.

  20. Affinity enhancement of antibodies: how low-affinity antibodies produced early in immune responses are followed by high-affinity antibodies later and in memory B-cell responses.

    Science.gov (United States)

    Eisen, Herman N

    2014-05-01

    The antibodies produced initially in response to most antigens are high molecular weight (MW) immunoglobulins (IgM) with low affinity for the antigen, while the antibodies produced later are lower MW classes (e.g., IgG and IgA) with, on average, orders of magnitude higher affinity for that antigen. These changes, often termed affinity maturation, take place largely in small B-cell clusters (germinal center; GC) in lymphoid tissues in which proliferating antigen-stimulated B cells express the highly mutagenic cytidine deaminase that mediates immunoglobulin class-switching and sequence diversification of the immunoglobulin variable domains of antigen-binding receptors on B cells (BCR). Of the large library of BCR-mutated B cells thus rapidly generated, a small minority with affinity-enhancing mutations are selected to survive and differentiate into long-lived antibody-secreting plasma cells and memory B cells. BCRs are also endocytic receptors; they internalize and cleave BCR-bound antigen, yielding peptide-MHC complexes that are recognized by follicular helper T cells. Imperfect correlation between BCR affinity for antigen and cognate T-cell engagement may account for the increasing affinity heterogeneity that accompanies the increasing average affinity of antibodies. Conservation of mechanisms underlying mutation and selection of high-affinity antibodies over the ≈200 million years of evolution separating bird and mammal lineages points to the crucial role of antibody affinity enhancement in adaptive immunity.

  1. Symbolic Dynamics for a Piecewise-Affine System with Hysteresis

    OpenAIRE

    Sella, Lorenzo; Collins, Pieter

    2008-01-01

    In this paper we present the computation of symbolic dynamics of a one dimensional return map of a piecewise-affine hybrid system. The system arises as a simple electrical circuit with hysteresis switching, and exhibits chaotic dynamics. Our method allows us to rigorously obtain a qualitative description of the discrete behaviour of the system. We show how the discrete dynamics changes as a parameter is varied, and we compute bounds for the topological entropy to provide a measure of the comp...

  2. Identification and Estimation of Gaussian Affine Term Structure Models

    OpenAIRE

    Hamilton, James D.; Jing Cynthia Wu

    2012-01-01

    This paper develops new results for identification and estimation of Gaussian affine term structure models. We establish that three popular canonical representations are unidentified, and demonstrate how unidentified regions can complicate numerical optimization. A separate contribution of the paper is the proposal of minimum-chi-square estimation as an alternative to MLE. We show that, although it is asymptotically equivalent to MLE, it can be much easier to compute. In some cases, MCSE allo...

  3. A pulse radiolysis study on electron affinity of piperonal

    Institute of Scientific and Technical Information of China (English)

    MA; Jianhua; LIN; Weizhen; WANG; Wenfeng; YAO; Side

    2005-01-01

    The piperonal electron affinity was studied using pulse radiolysis technique. The electron transfer reaction process between piperonal and anthraquinone-2-sulfate was observed in the pH 7 phosphoric acid salt buffer. The transient absorption spectra of electron transfer reaction between piperonal and anthraquinone-2-sulfate were obtained, and the initial proof of the electron transfer between electron donor and acceptor was provided directly. The one-electron reduction potential of piperonal was determined to be -0.457 V.

  4. Affinity Purification of Protein Complexes Using TAP Tags

    Science.gov (United States)

    Gerace, Erica; Moazed, Danesh

    2016-01-01

    This protocol is used for the isolation and analysis of protein complexes using the tandem affinity purification (TAP) tag system. The protocol describes the purification of a protein fused to a TAP tag comprised of two protein A domains and the calmodulin binding peptide separated by a TEV cleavage site. This is a powerful technique for rapid purification of protein complexes and the analysis of their stoichiometric composition, posttranslational modifications, structure, and functional activities. PMID:26096502

  5. PREPARATION OF CHITOSAN COATED METAL AFFINITY CHROMATOGRAPHY ADSORBENT

    Institute of Scientific and Technical Information of China (English)

    AanTianwei; XuWeijiang; 等

    1998-01-01

    A new and an inexpensive adsorbent of chitosan coated silica for immobilized metal affinity chromatography(IMAC) was studied.After a double coating,the chitosan coated on silica beads could be up to 53.4mg/g silica beads.When pH>3.8,the metal ligand Cu2+ was chelated on the coated chitosan with a bound capacity of 14.6mg/g chitosan without introducing iminodiacetic acid(IDA).

  6. Communication: Revised electron affinity of SF6 from kinetic data.

    OpenAIRE

    Troe, J.; Miller, T; Viggiano, A.

    2012-01-01

    Previously determined experimental data for thermal attachment of electrons to SF 6 and thermal detachment from SF 6 − over the range 590–670 K are reevaluated by a third-law analysis. Recent high precision calculations of SF 6 − harmonic frequences and anharmonicities (for several of the modes) lead to considerable changes in modeled vibrational partition functions which then have to be accommodated for by a smaller value of the derived adiabatic electron affinity EA of SF 6 . The previously...

  7. Agonist binding to high-affinity dopamine sites

    Energy Technology Data Exchange (ETDEWEB)

    Tedesco, J.L.

    1985-01-01

    The authors have characterized the dopamine D/sub 3/ site and its binding requirements. The dopamine D/sub 3/ site in calf caudate crude homogenate has a site density of 214-230 fmoles/mg. protein by both /sup 3/H-apomorphine (/sup 3/H-AOP) and /sup 3/H-dopamine (/sup 3/H-DA) Scatchard analysis of specific binding (SB). Stereospecific subsets of /sup 3/H-APO and /sup 3/H-DA sites were defined by the use of agonist and antagonist enantiomer-pairs as a rigorous test for D/sub 3/ site heterogeneity. IC/sub 50/ values for both /sup 3/H-APO and /sup 3/H-DA SB sites were assessed for 55 agonist ligands and an excellent correlation was obtained. The authors conclude that both /sup 3/H-ligands label the same D/sub 3/ site. The D/sub 3/ site affinities of 105 dopamine-agonist ligands, in particular 2-aminotetralins,, aporphines and flexible dopamine analogues were measured. Low D/sub 3/-site affinities of N-quaternary analogues confirm the need for a lone pair. Subadditivity of substituents' effects in semi-flexible DA analogues confirms their postulate that sidechain conformation is the critical determinant of affinity. They conclude that there are at least two high-affinity ligand conformations of the DA sidechain pharmacophore. These binding requirements are presented as two interface-Geometry tetrahedral models of the double H-bond interface between the D/sub 3/ site and the ideal ligand.

  8. Term premia and interest rate forecasts in affine models

    OpenAIRE

    Duffee, Gregory R.

    2000-01-01

    I find that the standard class of affine models produces poor forecasts of future changes in Treasury yields. Better forecasts are generated by assuming that yields follow random walks. The failure of these models is driven by one of their key features: the compensation that investors receive for facing risk is a multiple of the variance of the risk. This means that risk compensation cannot vary independently of interest rate volatility. I also describe and empirically estimate a class of mod...

  9. Affinity purification of polysaccharide degrading enzymes with crosslinked substrates.

    OpenAIRE

    Rozie, H.J.

    1992-01-01

    The aim of this work was to find economically favourable, affinity based, purification methods for several polysaccharide splitting bulk enzymes. The framework in which this study is done is described in Chapter 1.Chapter 2 describes the adsorption of endo-polygalacturonase (endoPG) from a commercial enzyme preparation (Rapidase) to calcium alginate beads. Approximately 75% of the various polygalacturonase activities from Rapidase can be adsorbed at pH 4.4 by calcium alginate beads as well as...

  10. Affine-Detection Loophole in Quantum Data Processing

    OpenAIRE

    Vlasov, Alexander Yu.

    2002-01-01

    Here is considered a specific detection loophole, that is relevant not only to testing of quantum nonlocality, but also to some other applications of quantum computations and communications. It is described by a simple affine relation between different quantum "data structures" like pure and mixed state, separable and inseparable one. It is shown also, that due to such relations imperfect device for a classical model may mimic measurements of quantum correlations on ideal equipment.

  11. Ferromagnetic Levan Composite: An Affinity Matrix to Purify Lectin

    OpenAIRE

    Renata Angeli; da Paz, Nathalia V. N.; Maciel, Jackeline C.; Flávia F. B. Araújo; Paiva, Patrícia M. G.; Glícia M. T. Calazans; Ana Paula Valente; Almeida, Fábio C. L.; Coelho, Luana C. B. B.; Carvalho, Luiz B; Silva, Maria da Paz C.; Maria Tereza dos Santos Correia

    2009-01-01

    A simple and inexpensive procedure used magnetite and levan to synthesize a composite recovered by a magnetic field. Lectins from Canavalia ensiformis (Con A) and Cratylia mollis (Cramoll 1 and Cramoll 1, 4) did bind specifically to composite. The magnetic property of derivative favored washing out contaminating proteins and recovery of pure lectins with glucose elution. Cramoll 1 was purified by this affinity binding procedure in two steps instead of a previous three-step protocol with ammon...

  12. The relation of morphology and affinity maturation in germinal centers

    CERN Document Server

    Meyer-Hermann, M

    2002-01-01

    The specific morphology of germinal centers is analyzed in the context of the optimization of the humoral immune response. The relevance of dark and light zones for the affinity maturation process is investigated in the framework of a theoretical model for the germinal center reaction. Especially, it is shown that an intermediate appearance of dark zones in germinal center reactions is advantageous for the process of antibody optimization.

  13. Macro factors and the affine term structure of interest rates

    OpenAIRE

    Tao Wu

    2001-01-01

    I formulate an affine term structure model of bond yields from a general equilibrium business-cycle model, with observable macro state variables of the structural economy as the factors. The factor representing monetary policy is strongly mean-reverting, and its influence on the term structure is primarily through changing the slope of the yield curve. The factor representing technology is more persistent, and it affects the term structure by shifting the level of the yield curve. The dynamic...

  14. Affinity chromatography based on a combinatorial strategy for rerythropoietin purification.

    Science.gov (United States)

    Martínez-Ceron, María C; Marani, Mariela M; Taulés, Marta; Etcheverrigaray, Marina; Albericio, Fernando; Cascone, Osvaldo; Camperi, Silvia A

    2011-05-01

    Small peptides containing fewer than 10 amino acids are promising ligand candidates with which to build affinity chromatographic systems for industrial protein purification. The application of combinatorial peptide synthesis strategies greatly facilitates the discovery of suitable ligands for any given protein of interest. Here we sought to identify peptide ligands with affinity for recombinant human erythropoietin (rhEPO), which is used for the treatment of anemia. A combinatorial library containing the octapeptides X-X-X-Phe-X-X-Ala-Gly, where X = Ala, Asp, Glu, Phe, His, Leu, Asn, Pro, Ser, or Thr, was synthesized on HMBA-ChemMatrix resin by the divide-couple-recombine method. For the library screening, rhEPO was coupled to either Texas Red or biotin. Fluorescent beads or beads showing a positive reaction with streptavidin-peroxidase were isolated. After cleavage, peptides were sequenced by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Fifty-seven beads showed a positive reaction. Peptides showing more consensuses were synthesized, and their affinity to rhEPO was assessed using a plasma resonance biosensor. Dissociation constant values in the range of 1-18 μM were obtained. The best two peptides were immobilized on Sepharose, and the resultant chromatographic matrixes showed affinity for rhEPO with dissociation constant values between 1.8 and 2.7 μM. Chinese hamster ovary (CHO) cell culture supernatant was spiked with rhEPO, and the artificial mixture was loaded on Peptide-Sepharose columns. The rhEPO was recovered in the elution fraction with a yield of 90% and a purity of 95% and 97% for P1-Sepharose and P2-Sepharose, respectively. PMID:21495625

  15. Affine transformations capture beak shape variation in Darwin's Finches

    Science.gov (United States)

    Brenner, Michael; Campas, Otger; Mallarino, Riccardo; Abzhanov, Arhat

    2009-11-01

    Evolution by natural selection has resulted in extraordinary morphological complexity of living organisms, whose description has thus far defied any precise mathematical characterization linked to the underlying developmental genetics. Here we demonstrate that the morphological diversity of the beaks of Darwin's finches, the classical example of adaptive morphological radiation, is quantitatively accounted for through the mathematical group of affine transformations. Specifically, we show that all beak shapes of Ground Finches (genus Geospiza) are related by scaling transformations (a subgroup of the affine group), and the same scheme occurs for all the beak shapes of Tree and Warbler finches. This analysis shows that the beak shapes within each of these groups differ only by their scales, such as length and depth, each of which is knownto be under genetic control.The complete morphological variability within the beaks of Darwin's finches can be explained by extending the scaling transformations to the entire affine group, by including shear transformations. Altogether our results suggest that the mathematical theory of groups can help decode morphological variability, and points to a potentially hierarchical structure of morphological diversity and the underlying developmental processes.

  16. Affitins for protein purification by affinity magnetic fishing.

    Science.gov (United States)

    Fernandes, Cláudia S M; Dos Santos, Raquel; Ottengy, Stella; Viecinski, Aline Canani; Béhar, Ghislaine; Mouratou, Barbara; Pecorari, Frédéric; Roque, A Cecília A

    2016-07-29

    Currently most economical and technological bottlenecks in protein production are placed in the downstream processes. With the aim of increasing the efficiency and reducing the associated costs, various affinity ligands have been developed. Affitins are small, yet robust and easy to produce, proteins derived from the archaeal extremophilic "7kDa DNA-binding" protein family. By means of combinatorial protein engineering and ribosome display selection techniques, Affitins have shown to bind a diversity of targets. In this work, two previously developed Affitins (anti-lysozyme and anti-IgG) were immobilized onto magnetic particles to assess their potential for protein purification by magnetic fishing. The optimal lysozyme and human IgG binding conditions yielded 58mg lysozyme/g support and 165mgIgG/g support, respectively. The recovery of proteins was possible in high yield (≥95%) and with high purity, namely ≥95% and 81%, when recovering lysozyme from Escherichia coli supernatant and IgG from human plasma, respectively. Static binding studies indicated affinity constants of 5.0×10(4)M(-1) and 9.3×10(5)M(-1) for the anti-lysozyme and anti-IgG magnetic supports. This work demonstrated that Affitins, which can be virtually evolved for any protein of interest, can be coupled onto magnetic particles creating novel affinity adsorbents for purification by magnetic fishing. PMID:27342136

  17. Con A affinity glycoproteomics of normal human liver tissue

    Institute of Scientific and Technical Information of China (English)

    SUN QiangLing; LU HaoJie; LIU YinKun; LU WenJing; CHENG Gang; ZHOU HaiJun; ZHOU XinWen; WEI LiMing; DAI Zhi; GUO Kun

    2007-01-01

    In order to establish the novel high throughput, high efficiency and Iow cost technological platform for the research of N-glycoproteomics, to resolve the significance of characteristic expression profile of glycoprotein and to find the proteins with biological functional importance, the glycoproteins with high-mannose core and the two antennary types were purified and enriched by the Con A affinity chromatography. Con A affinity protein expression profiles of normal human liver tissue were generated by using SDS-PAGE, two-dimensional electrophoresis (2-DE) followed by fast fluorescence staining based on multiplexed proteomics (MP) technology. 301 visible protein spots on the gel were detected and 85 of glycoproteins were further successfully identified via peptide mass fingerprinting (PMF) by a matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS/MS) and annotated to IPI databases. Identified glycoproteins definitely take part in the regulation of cell cycle and metabolic processes. The glycosylation sites were predicted with NetNGlyc 1.0 and NetOGlyc 3.1 software, meanwhile they were classified according to the geneontology methods. The construction of Con A affinity glycoprotein database of normal human liver tissue would contribute to the subsequent research.

  18. Exact deformations of quantum groups; applications to the affine case

    CERN Document Server

    Frønsdal, Christian

    1996-01-01

    This paper continues our investigation of a class of generalized quantum groups. The ``standard" R-matrix was shown to be the unique solution of a very simple, linear recursion relation and the classical limit was obtained in the case of quantized Kac-Moody algebras of finite type. Here the standard R-matrix for generalized quantum groups is first examined in the case of quantized affine Kac-Moody algebras. The classical limit yields the standard affine r-matrices of Belavin and Drinfeld. Then, turning to the general case, we study the exact deformations of the standard R-matrix and the associated Hopf algebras. They are described as a generalized twist, R_\\epsilon = (F^t)^{-1}RF, where R is the standard R-matrix and F (a power series in the deformation parameter \\epsilon) is the solution of a linear recursion relation of the same type as that which determines R. Specializing again, to the case of quantized, affine Kac-Moody algebras, and taking the classical limit of these esoteric quantum groups, one re-dis...

  19. Con A affinity glycoproteomics of normal human liver tissue

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to establish the novel high throughput, high efficiency and low cost technological platform for the research of N-glycoproteomics, to resolve the significance of characteristic expression profile of glycoprotein and to find the proteins with biological functional importance, the glycoproteins with high-mannose core and the two antennary types were purified and enriched by the Con A affinity chromatography. Con A affinity protein expression profiles of normal human liver tissue were gener- ated by using SDS-PAGE, two-dimensional electrophoresis (2-DE) followed by fast fluorescence stain- ing based on multiplexed proteomics (MP) technology. 301 visible protein spots on the gel were de- tected and 85 of glycoproteins were further successfully identified via peptide mass fingerprinting (PMF) by a matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF- MS/MS) and annotated to IPI databases. Identified glycoproteins definitely take part in the regulation of cell cycle and metabolic processes. The glycosylation sites were predicted with NetNGlyc 1.0 and NetOGlyc 3.1 software, meanwhile they were classified according to the geneontology methods. The construction of Con A affinity glycoprotein database of normal human liver tissue would contribute to the subsequent research.

  20. Structure of Greyhound hemoglobin: origin of high oxygen affinity.

    Science.gov (United States)

    Bhatt, Veer S; Zaldívar-López, Sara; Harris, David R; Couto, C Guillermo; Wang, Peng G; Palmer, Andre F

    2011-05-01

    This study presents the crystal structure of Greyhound hemoglobin (GrHb) determined to 1.9 Å resolution. GrHb was found to crystallize with an α₁β₁ dimer in the asymmetric unit and belongs to the R2 state. Oxygen-affinity measurements combined with the fact that GrHb crystallizes in the R2 state despite the high-salt conditions used for crystallization strongly indicate that GrHb can serve as a model high-oxygen-affinity hemoglobin (Hb) for higher mammals, especially humans. Structural analysis of GrHb and its comparison with the R2-state of human Hb revealed several regions that can potentially contribute to the high oxygen affinity of GrHb and serve to rationalize the additional stability of the R2-state of GrHb. A previously well studied hydrophobic cluster of bar-headed goose Hb near α119 was also incorporated in the comparison between GrHb and human Hb. Finally, a structural comparison with generic dog Hb and maned wolf Hb was conducted, revealing that in contrast to GrHb these structures belong to the R state of Hb and raising the intriguing possibility of an additional allosteric factor co-purifying with GrHb that can modulate its quaternary structure. PMID:21543841

  1. Synthesis and NMDA receptor affinity of fluorinated dioxadrol analogues.

    Science.gov (United States)

    Banerjee, Ashutosh; Schepmann, Dirk; Wünsch, Bernhard

    2010-06-01

    A series of dioxadrol analogues with fluorine substituents in position 4 of the piperidine ring has been synthesized and pharmacologically evaluated. The key step in the synthesis was the fluorination of diastereomeric piperidones 6a and 6c as well as diastereomeric alcohols 9a and 9c with DAST. The reaction of the alcohols 9a and 9c took place with inversion of configuration. After removal of the Cbz-protective group, the NMDA receptor affinities of the resulting secondary amines 8a, 8c, 12b, and 12d were investigated in receptor binding studies. It was shown that the like-configuration of the ring junction was crucial for high NMDA receptor affinity. An axially oriented fluorine atom in position 4 led to 2-(2,2-diphenyl-1,3-dioxolan-4-yl)-4-fluoropiperidine (12d, WMS-2517) with a K(i)-value of 27nM. The NMDA receptor affinity of 8c (WMS-2513) with an additional fluorine atom in equatorial 4-position was slightly reduced (K(i)=81 nM). Both fluorinated dioxadrol derivatives 8c and 12d showed high selectivity against sigma(1) and sigma(2) receptors as well as the polyamine binding site of NR2B receptors.

  2. Nanoparticle Surface Affinity as a Predictor of Trophic Transfer.

    Science.gov (United States)

    Geitner, Nicholas K; Marinakos, Stella M; Guo, Charles; O'Brien, Niall; Wiesner, Mark R

    2016-07-01

    Nanoscale materials, whether natural, engineered, or incidental, are increasingly acknowledged as important components in large, environmental systems with potential implications for environmental impact and human health. Mathematical models are a useful tool for handling the rapidly increasing complexity and diversity of these materials and their exposure routes. Presented here is a mathematical model of trophic transfer driven by nanomaterial surface affinity for environmental and biological surfaces, developed in tandem with an experimental functional assay for determining these surface affinities. We found that nanoparticle surface affinity is a strong predictor of uptake through predation in a simple food web consisting of the algae Chlorella vulgaris and daphnid Daphnia magna. The mass of nanoparticles internalized by D. magna through consuming nanomaterial-contaminated algae varied linearly with surface-attachment efficiency. Internalized quantities of gold nanoparticles in D. magna ranged from 8.3 to 23.6 ng/mg for nanoparticle preparations with surface-attachment efficiencies ranging from 0.07 to 1. This model, coupled with the functional-assay approach, may provide a useful screening tool for existing materials as well as a predictive model for their development. PMID:27249534

  3. Relative Binding Affinities of Monolignols to Horseradish Peroxidase.

    Science.gov (United States)

    Sangha, Amandeep K; Petridis, Loukas; Cheng, Xiaolin; Smith, Jeremy C

    2016-08-11

    Monolignol binding to the peroxidase active site is the first step in lignin polymerization in plant cell walls. Using molecular dynamics, docking, and free energy perturbation calculations, we investigate the binding of monolignols to horseradish peroxidase C. Our results suggest that p-coumaryl alcohol has the strongest binding affinity followed by sinapyl and coniferyl alcohol. Stacking interactions between the monolignol aromatic rings and nearby phenylalanine residues play an important role in determining the calculated relative binding affinities. p-Coumaryl and coniferyl alcohols bind in a pose productive for reaction in which a direct H-bond is formed between the phenolic -OH group and a water molecule (W2) that may facilitate proton transfer during oxidation. In contrast, in the case of sinapyl alcohol there is no such direct interaction, the phenolic -OH group instead interacting with Pro139. Since proton and electron transfer is the rate-limiting step in monolignol oxidation by peroxidase, the binding pose (and thus the formation of near attack conformation) appears to play a more important role than the overall binding affinity in determining the oxidation rate. PMID:27447548

  4. Supramolecular Affinity Chromatography for Methylation-Targeted Proteomics.

    Science.gov (United States)

    Garnett, Graham A E; Starke, Melissa J; Shaurya, Alok; Li, Janessa; Hof, Fraser

    2016-04-01

    Proteome-wide studies of post-translationally methylated species using mass spectrometry are complicated by high sample diversity, competition for ionization among peptides, and mass redundancies. Antibody-based enrichment has powered methylation proteomics until now, but the reliability, pan-specificity, polyclonal nature, and stability of the available pan-specific antibodies are problematic and do not provide a standard, reliable platform for investigators. We have invented an anionic supramolecular host that can form host-guest complexes selectively with methyllysine-containing peptides and used it to create a methylysine-affinity column. The column resolves peptides on the basis of methylation-a feat impossible with a comparable commercial cation-exchange column. A proteolyzed nuclear extract was separated on the methyl-affinity column prior to standard proteomics analysis. This experiment demonstrates that such chemical methyl-affinity columns are capable of enriching and improving the analysis of methyllysine residues from complex protein mixtures. We discuss the importance of this advance in the context of biomolecule-driven enrichment methods. PMID:26973166

  5. A Quick and Affine Invariance Matching Method for Oblique Images

    Directory of Open Access Journals (Sweden)

    XIAO Xiongwu

    2015-04-01

    Full Text Available This paper proposed a quick, affine invariance matching method for oblique images. It calculated the initial affine matrix by making full use of the two estimated camera axis orientation parameters of an oblique image, then recovered the oblique image to a rectified image by doing the inverse affine transform, and left over by the SIFT method. We used the nearest neighbor distance ratio(NNDR, normalized cross correlation(NCC measure constraints and consistency check to get the coarse matches, then used RANSAC method to calculate the fundamental matrix and the homography matrix. And we got the matches that they were interior points when calculating the homography matrix, then calculated the average value of the matches' principal direction differences. During the matching process, we got the initial matching features by the nearest neighbor(NN matching strategy, then used the epipolar constrains, homography constrains, NCC measure constrains and consistency check of the initial matches' principal direction differences with the calculated average value of the interior matches' principal direction differences to eliminate false matches. Experiments conducted on three pairs of typical oblique images demonstrate that our method takes about the same time as SIFT to match a pair of oblique images with a plenty of corresponding points distributed evenly and an extremely low mismatching rate.

  6. Reverse mode Na+/Ca2+ exchange mediated by STIM1 contributes to Ca2+ influx in airway smooth muscle following agonist stimulation

    Directory of Open Access Journals (Sweden)

    Fox Jane

    2010-12-01

    Full Text Available Abstract Background Agonist stimulation of airway smooth muscle (ASM results in IP3 mediated Ca2+ release from the sarcoplasmic reticulum followed by the activation of store operated and receptor operated non-selective cation channels. Activation of these non-selective channels also results in a Na+ influx. This localised increase in Na+ levels can potentially switch the Na+/Ca2+ exchanger into reverse mode and so result in a further influx of Ca2+. The aim of this study was to characterise the expression and physiological function of the Na+/Ca2+ exchanger in cultured human bronchial smooth muscle cells and determine its contribution to agonist induced Ca2+ influx into these cells. Methods The expression profile of NCX (which encodes the Na+/Ca2+ exchanger homologues in cultured human bronchial smooth muscle cells was determined by reverse transcriptase PCR. The functional activity of reverse mode NCX was investigated using a combination of whole cell patch clamp, intracellular Ca2+ measurements and porcine airway contractile analyses. KB-R7943 (an antagonist for reverse mode NCX and target specific siRNA were utilised as tools to inhibit NCX function. Results NCX1 protein was detected in cultured human bronchial smooth muscle cells (HBSMC cells and NCX1.3 was the only mRNA transcript variant detected. A combination of intracellular Na+ loading and addition of extracellular Ca2+ induced an outwardly rectifying current which was augmented following stimulation with histamine. This outwardly rectifying current was inhibited by 10 μM KB-R7943 (an antagonist of reverse mode NCX1 and was reduced in cells incubated with siRNA against NCX1. Interestingly, this outwardly rectifying current was also inhibited following knockdown of STIM1, suggesting for the first time a link between store operated cation entry and NCX1 activation. In addition, 10 μM KB-R7943 inhibited agonist induced changes in cytosolic Ca2+ and induced relaxation of porcine

  7. Downregulation of transcription factor Oct4 induces an epithelial-to-mesenchymal transition via enhancement of Ca{sup 2+} influx in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jiajia; Qin, Kunhua; Zhang, Yan [Medical School of Nankai University, 94 Weijin Road, Tianjin 300071 (China); Gong, Junbo [Tianjin Key Laboratory of Modern Drug Delivery and High Efficiency in Tianjin University, 92 Weijin Road, Tianjin 300072 (China); Li, Na; Lv, Dan; Xiang, Rong [Medical School of Nankai University, 94 Weijin Road, Tianjin 300071 (China); Tan, Xiaoyue, E-mail: xiaoyuetan@nankai.edu.cn [Medical School of Nankai University, 94 Weijin Road, Tianjin 300071 (China)

    2011-08-12

    Highlights: {yields} We examine the role of Oct4 in metastasis in cultured MCF-7 cells. {yields} The down regulation of Oct4 induces EMT and increases the capability of migration and invasion in MCF-7 cells. {yields} TGF-{beta}1 inhibits Oct4 expression in both time- and dose-dependent manners. {yields} The EMT induced by TGF-{beta}1 or down regulation of Oct4 could be abrogated by inhibitor of SOCE. {yields} The down regulation of STIM1 (one of the major components of the CRAC channel) alleviates the EMT induce by Oct4 silencing down. -- Abstract: The stem cell-related transcription factor Oct4 regulates tumor proliferation and apoptosis, but its role in tumor migration and invasion is still undefined. Here, we compared Oct4 expression in MCF-7 and MDA-MB-231 cells, two breast cancer cell lines with similar epithelial origins, but distinct invasive and metastatic characteristics. We found MCF-7 cells to express very high levels of Oct4, while no obvious expression was detected in MDA-MB-231 cells. We then downregulated Oct4 expression using small interfering RNA (siRNA) to explore its effects on migration and invasion. Transwell assays showed that silencing Oct4 in MCF-7 cells improved their migration and invasion capabilities. Reverse-transcriptase PCR and western blots showed that E-cadherin expression decreased, and {alpha}-smooth muscle actin expression increased with Oct4 downregulation, which suggests that epithelial-to-mesenchymal transition (EMT) occurred. A potent EMT stimulus, TGF-{beta}1, significantly inhibited Oct4 expression in both dose- and time course-dependent manners. Silencing Oct4 also upregulated expression of two major components of store-operated Ca{sup 2+} entry channels (SOCs), STIM1 and Orai1, and enhanced SOC-directed Ca{sup 2+} influx. Silencing STIM1 blocked the Ca{sup 2+} influx and rescued the EMT initiated by Oct4 downregulation. In conclusion, silencing Oct4 promotes invasion and metastasis in breast cancer cells by inducing EMT

  8. The Purification of a Blood Group A Glycoprotein: An Affinity Chromatography Experiment.

    Science.gov (United States)

    Estelrich, J.; Pouplana, R.

    1988-01-01

    Describes a purification process through affinity chromatography necessary to obtain specific blood group glycoproteins from erythrocytic membranes. Discusses the preparation of erythrocytic membranes, extraction of glycoprotein from membranes, affinity chromatography purification, determination of glycoproteins, and results. (CW)

  9. Robust adaptive control for a class of uncertain non-affine nonlinear systems using affine-type neural networks

    Science.gov (United States)

    Zhao, Shitie; Gao, Xianwen

    2016-08-01

    A robust adaptive control is proposed for a class of single-input single-output non-affine nonlinear systems. In order to approximate the unknown nonlinear function, a novel affine-type neural network is used, and then to compensate the approximation error and external disturbance a robust control term is employed. By Lyapunov stability analysis for the closed-loop system, it is proved that tracking errors asymptotically converge to zero. Moreover, an observer is designed to estimate the system states because all the states may not be available for measurements. Furthermore, the adaptation laws of neural networks and the robust controller are given out based on the Lyapunov stability theory. Finally, two simulation examples are presented to demonstrate the effectiveness of the proposed control method.

  10. Consumer affinity for foreign countries: construct development, buying behavior consequences and animosity contrasts

    OpenAIRE

    Nes, Erik B.; Yelkur, Rama; Silkoset, Ragnhild

    2014-01-01

    Purpose: Our purpose is to extend affinity theory in construct domain, scale development, model testing and by discerning affinity and animosity. Design/methodology/approach: We carry out exploratory and empirical research in order to explore the domain and to test the factor structure and the hypotheses through confirmatory analysis. Findings: We find (1) four target country affinity dimensions, (2) consumer affinity impacts micro country image, buying intentions and actual product own...

  11. Inhibitory effect of acteoside on melittin-induced catecholamine exocytosis through inhibition of Ca(2+)-dependent phospholipase A2 and extracellular Ca(2+) influx in PC12 cells.

    Science.gov (United States)

    Song, Ho Sun; Ko, Myung Soo; Jo, Young Soo; Whang, Wan Kyunn; Sim, Sang Soo

    2015-10-01

    To investigate the inhibitory effect of acteoside on the process of exocytosis induced by melittin, we measured Ca(2+) mobilization, arachidonic acid (AA) release and catecholamine exocytosis in PC12 chromaffin cells. Melittin significantly increased the intracellular Ca(2+) mobilization via receptor-operated calcium channel but not the intracellular Ca(2+) release. It caused AA release via activation of Ca(2+)-dependent phospholipase A2 (PLA2) and catecholamine secretion in a dose-dependent manner. Acteoside dose-dependently inhibited the release of AA and intracellular Ca(2+) mobilization induced by melittin. Acteoside reduced the catecholamine release and raised the amount of intracellular chromogranin A which is co-released with catecholamine from melittin-stimulated PC12 cells. Taken together, our results suggest that acteoside could suppress the exocytosis via inhibition of Ca(2+)-dependent PLA2 and extracellular Ca(2+) influx in PC12 cells stimulated by melittin. PMID:25899996

  12. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2 leading to cell depolarization and calcium influx

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Hartmann, Bolette;

    2015-01-01

    , but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways......Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans...... of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide...

  13. Induces vasodilatation of rat mesenteric artery in vitro mainly by inhibiting receptor-mediated Ca(2+)-influx and Ca(2+)-release

    DEFF Research Database (Denmark)

    Cao, Yong-Xiao; Zheng, Jian-Pu; He, Jian-Yu;

    2005-01-01

    The purpose of this study was to investigate the effect of atropine on peripheral vasodilation and the mechanisms involved. The isometric tension of rat mesenteric artery rings was recorded in vitro on a myograph. The results showed that atropine, at concentrations greater than 1 microM, relaxed...... the contraction derived from NA and CaCI2 in Ca(2+)-free medium, in a concentration dependent manner, indicating the vasodilatation was related to the inhibition of extracellular Ca2+ influx through the receptor-operated calcium channels and intracellular Ca2+ release from the Ca2+ store. Atropine had no effect...... on the caffeine-induced contraction in the artery segments, indicating the inhibition of intracellular Ca2+ release as a result of atropine most likely occurs via the IP3 pathway rather than the ryanodine receptors. Our results suggest that atropine-induced vasodilatation is mainly from artery smooth muscle cells...

  14. CXCR2 antagonists block the N-Ac-PGP-induced neutrophil influx in the airways of mice, but not the production of the chemokine CXCL1.

    Science.gov (United States)

    Braber, Saskia; Overbeek, Saskia A; Koelink, Pim J; Henricks, Paul A J; Zaman, Guido J R; Garssen, Johan; Kraneveld, Aletta D; Folkerts, Gert

    2011-10-15

    Neutrophils are innate immune cells in chronic inflammatory diseases including chronic obstructive pulmonary disease (COPD) and can be attracted to the site of inflammation via the collagen breakdown product N-acetyl Proline-Glycine-Proline (N-Ac-PGP). To elucidate whether CXCR2 is involved in N-Ac-PGP-induced neutrophil migration and activation, studies using specific antagonists were performed in vivo. N-Ac-PGP and keratinocyte cell-derived chemokine (KC; CXCL1) were administered in C57Bl/6 mice via oropharyngeal aspiration. Intraperitoneal applications of CXCR2 antagonist SB225002 or SB332235 were administered 1h prior and 1h after oropharyngeal aspiration. Six hours after oropharyngeal aspiration mice were sacrificed. Neutrophil counts and CXCL1 levels were determined in bronchoalveolar lavage fluid, myleoperoxidase (MPO) levels were measured in lung tissue homogenates and an immunohistological staining for neutrophils was performed on lung tissue. N-Ac-PGP and CXCL1 induced a neutrophil influx in the bronchoalveolar lavage fluid and lung tissue, which was also reflected by increased MPO levels in lung tissue. The N-Ac-PGP- and CXCL1-induced neutrophil influx and the increased pulmonary tissue MPO levels were inhibited by the CXCR2 antagonists SB225002 and SB332235. Moreover, N-Ac-PGP administration enhanced the CXCL1 levels in bronchoalveolar lavage fluid, which could not be attenuated by both CXCR2 antagonists. In conclusion, neutrophil migration induced by N-Ac-PGP is mediated via direct CXCR2 interaction. The N-Ac-PGP-induced release of CXCL1 is independent of CXCR2. Related to the maximal effect of CXCL1, N-Ac-PGP is more potent at inducing neutrophil migration in the pulmonary tissue than into the bronchoalveolar lavage fluid, or N-ac-PGP may be more potent at inducing MPO levels in the lung tissue.

  15. Modulation of Membrane Influx and Efflux in Escherichia coli Sequence Type 131 Has an Impact on Bacterial Motility, Biofilm Formation, and Virulence in a Caenorhabditis elegans Model.

    Science.gov (United States)

    Pantel, Alix; Dunyach-Remy, Catherine; Ngba Essebe, Christelle; Mesureur, Jennifer; Sotto, Albert; Pagès, Jean-Marie; Nicolas-Chanoine, Marie-Hélène; Lavigne, Jean-Philippe

    2016-05-01

    Energy-dependent efflux overexpression and altered outer membrane permeability (influx) can promote multidrug resistance (MDR). The present study clarifies the regulatory pathways that control membrane permeability in the pandemic clone Escherichia coli sequence type 131 (ST131) and evaluates the impact of efflux and influx modulations on biofilm formation, motility, and virulence in the Caenorhabditis elegans model. Mutants of two uropathogenic E. coli (UPEC) strains, MECB5 (ST131; H30-Rx) and CFT073 (ST73), as well as a fecal strain, S250 (ST131; H22), were in vitro selected using continuous subculture in subinhibitory concentrations of ertapenem (ETP), chloramphenicol (CMP), and cefoxitin (FOX). Mutations in genes known to control permeability were shown for the two UPEC strains: MECB5-FOX (deletion of 127 bp in marR; deletion of 1 bp and insertion of an IS1 element in acrR) and CFT073-CMP (a 1-bp deletion causing a premature stop in marR). We also demonstrated that efflux phenotypes in the mutants selected with CMP and FOX were related to the AcrAB-TolC pump, but also to other efflux systems. Alteration of membrane permeability, caused by underexpression of the two major porins, OmpF and OmpC, was shown in MECB5-ETP and mutants selected with FOX. Lastly, our findings suggest that efflux pump-overproducing isolates (CMP mutants) pose a serious threat in terms of virulence (significant reduction in worm median survival) and host colonization. Lack of porins (ETP and FOX mutants) led to a high level of antibiotic resistance in an H30-Rx subclone. Nevertheless, this adaptation created a physiological disadvantage (decreased motility and ability to form biofilm) associated with a low potential for virulence. PMID:26926643

  16. Modulation of Membrane Influx and Efflux in Escherichia coli Sequence Type 131 Has an Impact on Bacterial Motility, Biofilm Formation, and Virulence in a Caenorhabditis elegans Model

    Science.gov (United States)

    Pantel, Alix; Dunyach-Remy, Catherine; Ngba Essebe, Christelle; Mesureur, Jennifer; Sotto, Albert; Nicolas-Chanoine, Marie-Hélène

    2016-01-01

    Energy-dependent efflux overexpression and altered outer membrane permeability (influx) can promote multidrug resistance (MDR). The present study clarifies the regulatory pathways that control membrane permeability in the pandemic clone Escherichia coli sequence type 131 (ST131) and evaluates the impact of efflux and influx modulations on biofilm formation, motility, and virulence in the Caenorhabditis elegans model. Mutants of two uropathogenic E. coli (UPEC) strains, MECB5 (ST131; H30-Rx) and CFT073 (ST73), as well as a fecal strain, S250 (ST131; H22), were in vitro selected using continuous subculture in subinhibitory concentrations of ertapenem (ETP), chloramphenicol (CMP), and cefoxitin (FOX). Mutations in genes known to control permeability were shown for the two UPEC strains: MECB5-FOX (deletion of 127 bp in marR; deletion of 1 bp and insertion of an IS1 element in acrR) and CFT073-CMP (a 1-bp deletion causing a premature stop in marR). We also demonstrated that efflux phenotypes in the mutants selected with CMP and FOX were related to the AcrAB-TolC pump, but also to other efflux systems. Alteration of membrane permeability, caused by underexpression of the two major porins, OmpF and OmpC, was shown in MECB5-ETP and mutants selected with FOX. Lastly, our findings suggest that efflux pump-overproducing isolates (CMP mutants) pose a serious threat in terms of virulence (significant reduction in worm median survival) and host colonization. Lack of porins (ETP and FOX mutants) led to a high level of antibiotic resistance in an H30-Rx subclone. Nevertheless, this adaptation created a physiological disadvantage (decreased motility and ability to form biofilm) associated with a low potential for virulence. PMID:26926643

  17. Koszul duality of affine Kac-Moody algebras and cyclotomic rational DAHA

    CERN Document Server

    Shan, Peng; Vasserot, Eric

    2011-01-01

    We give a proof of the parabolic/singular Koszul duality for the category O of affine Kac-Moody algebras. The main new tool is a relation between moment graphs and finite codimensional affine Schubert varieties. We apply this duality to q-Schur algebras and to cyclotomic rational double affine Hecke algebras.

  18. 14 CFR 212.5 - Operation of affinity (pro rata) charters.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Operation of affinity (pro rata) charters. 212.5 Section 212.5 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION... Operation of affinity (pro rata) charters. An affinity (pro rata) charter operated by a certificated...

  19. Surface affinity role in graphoepitaxy of lamellar block copolymers

    Science.gov (United States)

    Claveau, G.; Quemere, P.; Argoud, M.; Hazart, J.; Pimenta Barros, P.; Sarrazin, A.; Posseme, N.; Tiron, R.; Chevalier, X.; Nicolet, C.; Navarro, C.

    2016-03-01

    Overcoming the optical limitations of 193nm immersion lithography can be achieved using Directed Self Assembly (DSA) of block-copolymers (BCPs) as a low-cost and versatile complementary technique. The goal of this paper is to investigate the potential of DSA to address line and space (L/S) high resolution patterning by performing the density multiplication of lines with the graphoepitaxy approach. As surface affinity is a key parameter in self-assembly, three variations, or "flavors", of DSA template affinity are investigated regarding several success criteria such as morphology control or defectivity. More precisely, both the methodology to register DSA defects and the impact of process parameters on defectivity are detailed. Using the 300mm pilot line available in LETI and Arkema's advanced materials, we investigate process optimization of DSA line/space patterning of a 38nm period lamellar PS-b-PMMA BCP (L38). For this study, our integration scheme, depicted in figure 2-1, is based on BCP self-assembly inside organic hard mask guiding patterns obtained using 193i nm lithography. Defect analysis coupled with the fine tuning of process parameters (annealing, brush material) provided the optimum conditions for the L38 self-assembly. Using such conditions, DSA using the three affinity flavors is investigated by means of SEM top-view and cross-section review. Lithographic performances of one selected flavor are then evaluated with the comparison of Process Windows (PWs) function of either commensurability, morphology or LWR. This work is a first step in finding the best process for an industrial graphoepitaxy approach.

  20. Tubular algebras and affine Kac-Moody algebras

    Institute of Scientific and Technical Information of China (English)

    Zheng-xin CHEN; Ya-nan LIN

    2007-01-01

    The purpose of this paper is to construct quotient algebras L(A)C1/I(A) of complex degenerate composition Lie algebras L(A)C1 by some ideals, where L(A)C1 is defined via Hall algebras of tubular algebras A, and to prove that the quotient algebras L(A)C1/I(A) are isomorphic to the corresponding affine Kac-Moody algebras. Moreover, it is shown that the Lie algebra Lre(A)C1 generated by A-modules with a real root coincides with the degenerate composition Lie algebra L(A)C1 generated by simple A-modules.

  1. Tubular algebras and affine Kac-Moody algebras

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The purpose of this paper is to construct quotient algebras L(A)1C/I(A) of complex degenerate composition Lie algebras L(A)1C by some ideals, where L(A)1C is defined via Hall algebras of tubular algebras A, and to prove that the quotient algebras L(A)1C/I(A) are isomorphic to the corresponding affine Kac-Moody algebras. Moreover, it is shown that the Lie algebra Lre(A)1C generated by A-modules with a real root coincides with the degenerate composition Lie algebra L(A)1C generated by simple A-modules.

  2. Corner detectors for affine invariant salient regions: is color important?

    OpenAIRE

    Sebe, Nicu; Gevers, Theo; Van De Weijer, Joost; Dijkstra, Sietse

    2006-01-01

    Recently, a lot of research has been done on the matching of images and their structures. Although the approaches are very different, most methods use some kind of point selection from which descriptors or a hierarchy are derived. We focus here on the methods that are related to the detection of points and regions that can be detected in an affine invariant way. Most of the previous research concentrated on intensity based methods. However, we show in this work that color information can make...

  3. Understanding proton affinity of tyrosine sidechain in hydrophobic confinement

    Indian Academy of Sciences (India)

    T G Abi; T Karmakar; S Taraphder

    2012-01-01

    Tyrosine is an important amino acid residue that plays a key role in several biochemical transformations such as, abstraction/donation of proton from/by its sidechain. We present here a density functional study on the proton affinity of tyrosine sidechain suspended inside the core of a single walled carbon nanotube that mimics the environment of protein structural pores and molecular channels. Tyrosine is found to exhibit a lower reactivity on confinement and unlike several other polar amino acid sidechains, its reactivity does not respond to hydrogen bonding with neighbouring hydroxyl groups.

  4. Affinity and Hostility in Divided Communities: a Mathematical Model

    CERN Document Server

    Thron, Christopher

    2015-01-01

    We propose, develop, and analyze a mathematical model of intergroup attitudes in a community that is divided between two distinct social groups (which may be distinguished by religion, ethnicity, or some other socially distinguishing factor). The model is based on very simple premises that are both intuitive and justified by sociological research. We investigate the behavior of the model in various special cases, for various model configurations. We discuss the stability of the model, and the continuous or discontinuous dependence of model behavior on various parameters. Finally, we discuss possible implications for strategies to improve intergroup affinity, and to defuse tension and prevent deterioration of intergroup relationships.

  5. Nine switch-affine neurons suffice for Turing universality.

    Science.gov (United States)

    Siegelmann, H T.; Margenstern, M

    1999-06-01

    In a previous work Pollack showed that a particular type of heterogeneous processor network is Turing universal. Siegelmann and Sontag (1991) showed the universality of homogeneous networks of first-order neurons having piecewise-linear activation functions. Their result was generalized by Kilian and Siegelmann (1996) to include various sigmoidal activation functions. Here we focus on a type of high-order neurons called switch-affine neurons, with piecewise-linear activation functions, and prove that nine such neurons suffice for simulating universal Turing machines. PMID:12662670

  6. Algebraic (Volume) Density Property for Affine Homogeneous Spaces

    OpenAIRE

    Kaliman, Shulim; Kutzschebauch, Frank

    2015-01-01

    Let $X$ be a connected affine homogenous space of a linear algebraic group $G$ over $\\C$. (1) If $X$ is different from a line or a torus we show that the space of all algebraic vector fields on $X$ coincides with the Lie algebra generated by complete algebraic vector fields on $X$. (2) Suppose that $X$ has a $G$-invariant volume form $\\omega$. We prove that the space of all divergence-free (with respect to $\\omega$) algebraic vector fields on $X$ coincides with the Lie algebra generated by di...

  7. Feedback control design for discrete-time piecewise affine systems

    Institute of Scientific and Technical Information of China (English)

    XU Jun; XIE Li-hua

    2007-01-01

    This paper investigates the design of state feedback and dynamic output feedback stabilizing controllers for discrete-time piecewise affine (PWA) systems. The main objective is to derive design methods that will incorporate the partition information of the PWA systems so as to reduce the design conservatism embedded in existing design methods. We first introduce a transformation that converts the feedback control design problem into a bilinear matrix inequality (BMI) problem. Then, two iterative algorithms are proposed to compute the feedback controllers characterized by the BMI. Several simulation examples are given to demonstrate the advantages of the proposed design.

  8. Jumps and twists in affine Toda field theories

    Directory of Open Access Journals (Sweden)

    Anastasia Doikou

    2015-04-01

    Full Text Available The concept of point-like “jump” defects is investigated in the context of affine Toda field theories. The Hamiltonian formulation is employed for the analysis of the problem. The issue is also addressed when integrable boundary conditions ruled by the classical twisted Yangian are present. In both periodic and boundary cases explicit expressions of conserved quantities as well as the relevant Lax pairs and sewing conditions are extracted. It is also observed that in the case of the twisted Yangian the bulk behavior is not affected by the presence of the boundaries.

  9. Jumps and twists in affine Toda field theories

    Energy Technology Data Exchange (ETDEWEB)

    Doikou, Anastasia, E-mail: A.Doikou@hw.ac.uk [Department of Mathematics, Heriot–Watt University, EH14 4AS, Edinburgh (United Kingdom); Department of Computer Engineering & Informatics, University of Patras, GR-Patras 26500 (Greece)

    2015-04-15

    The concept of point-like “jump” defects is investigated in the context of affine Toda field theories. The Hamiltonian formulation is employed for the analysis of the problem. The issue is also addressed when integrable boundary conditions ruled by the classical twisted Yangian are present. In both periodic and boundary cases explicit expressions of conserved quantities as well as the relevant Lax pairs and sewing conditions are extracted. It is also observed that in the case of the twisted Yangian the bulk behavior is not affected by the presence of the boundaries.

  10. Rotating Black Holes in Metric-Affine Gravity

    CERN Document Server

    Baekler, P; Baekler, Peter; Hehl, Friedrich W.

    2006-01-01

    Within the framework of metric-affine gravity (MAG, metric and an independent linear connection constitute spacetime), we find, for a specific gravitational Lagrangian and by using {\\it prolongation} techniques, a stationary axially symmetric exact solution of the vacuum field equations. This black hole solution embodies a Kerr-deSitter metric and the post-Riemannian structures of torsion and nonmetricity. The solution is characterized by mass, angular momentum, and shear charge, the latter of which is a measure for violating Lorentz invariance.

  11. Biospecific affinity chromatographic purification of octopine dehydrogenase from molluscs.

    Science.gov (United States)

    Mulcahy, P; Griffin, T; O'Carra, P

    1997-02-01

    The development of a biospecific affinity chromatographic method for the purification of octopine dehydrogenase from molluscs is described. The method utilizes immobilized NAD+ derivatives in conjunction with soluble specific substrates to promote binding. Using this method, octopine dehydrogenase has been purified to electrophoretic homogeneity in a single chromatographic step from three different marine invertebrate sources [the queen scallop, Chlamys opercularis (adductor muscle), the great scallop, Pecten maximus (adductor muscle), and the squid Loligo vulgaris (mantle muscle)]. However, the system is not applicable to the purification of octopine dehydrogenase from some other marine invertebrate sources investigated (the mussel Mytilus edulis and the topshell Monodonta lineata). PMID:9116492

  12. Peculiarities of Thermodynamic Simulation with the Method of Bound Affinity

    CERN Document Server

    Zilbergleyt, B

    2004-01-01

    Thermodynamic simulation of chemical and metallurgical systems is the only method to predict their equilibrium composition and is the most important application of chemical thermodynamics. The conventional strategy of simulation is always to find the most probable composition of the system, corresponding to thermodynamic equilibrium. Traditional simulation methods do not account for interactions within the chemical system. The Method of Bound Affinity (MBA) is based on the theory that explicitly takes into account interactions between subsystems of a complex chemical system and leads sometimes to essential differences in simulation results. This article discusses peculiarities of MBA application, exemplified by results for a complex system with a set of subsystems.

  13. Two measured completely different electron affinities for atomic Eu?

    Science.gov (United States)

    Msezane, A. Z.; Felfli, Z.

    2016-05-01

    Recently, the electron affinity (EA) of atomic Eu was measured to be 0.116?eV. This value is in outstanding agreement with the theoretically calculated values using the Regge pole and MCDF-RCI methods. Previously, the EA of Eu was measured to be 1.053 eV. In an attempt to resolve the discrepancy between the two measured values, we have adopted the complex angular momentum (CAM) method and investigated in the electron energy range 0.11 eV methane to methanol without CO2 emission. These new results call for immediate experimental and theoretical verification.

  14. Ca2+ entry in gonadotrophs and alpha T3-1 cells: does store-dependent Ca2+ influx mediate gonadotrophin-releasing hormone action?

    Science.gov (United States)

    McArdle, C A; Forrest-Owen, W; Davidson, J S; Fowkes, R; Bunting, R; Mason, W T; Poch, A; Kratzmeier, M

    1996-04-01

    In pituitary gonadotrophs GnRH causes biphasic (spike and plateau) increases in cytosolic Ca2+ ([Ca2+]i) and gonadotrophin release. The spike phases reflect mobilization of stored Ca2+ and the plateau responses are attributed, in part, to Ca2+ influx via voltage-sensitive Ca2+ channels. In recent years, store-dependent Ca2+ influx (SDCI), in which depletion of the intracellular inositol 1,4,5-trisphosphate-mobilizable pool stimulates Ca2+ influx, has emerged as a major form of Ca2+ entry activated by phosphoinositidase C-coupled receptors in non-excitable cells. More recent evidence also indicates a role for SDCI in excitable cells. We have used dynamic video imaging of [Ca2+]i in alpha T3-1 cells (a gonadotroph-derived cell line) and manipulation of the filling state of the GnRH-mobilizable Ca2+ pool to test the possible role of SDCI in GnRH action. In Ca(2+)-containing medium, GnRH caused a biphasic increase in [Ca2+]i whereas in Ca(2+)-free medium only a transient increase occurred. The response to a second stimulation with GnRH in Ca(2+)-free medium was reduced by > 95% (demonstrating that Ca2+ pool depletion had occurred) and was recovered after brief exposure to Ca(2+)-containing medium (which enables refilling of the pool). Ionomycin (a Ca2+ ionophore) and thapsigargin (which inhibits the Ca(2+)-sequestering ATPase of the endoplasmic reticulum) also transiently increased [Ca2+]i in Ca(2+)-free medium and depleted the GnRH-mobilizable pool as indicated by greatly reduced subsequent responses to GnRH. Pool depletion also occurs on stimulation with GnRH in Ca(2+)-containing medium because addition of ionomycin and Ca(2+)-free medium during the plateau phase of the GnRH response caused only a reduction in [Ca2+]i rather than the transient increase seen without GnRH. To deplete intracellular Ca2+ pools, cells were pretreated in Ca(2+)-free medium with thapsigargin or GnRH and then, after extensive washing, returned to Ca(2+)-containing medium. Pretreatment with

  15. Study on Removal of Bilirubin with Magnetic Affinity Separation Technique

    Institute of Scientific and Technical Information of China (English)

    张凤宝; 王淑兰; 徐辉; 张国亮

    2003-01-01

    An affinity adsorbent, Cibacron Blue 3GA immobilized magnetic polyvinyl alcohol (PVA) microspheres was used for bilirubin removal taking the advantage of easy separation of magnetic sorbent from the biosystem.Fe3 O4 superparamagnetic particles was synthesized with hydrothermal reaction of ferrous chloride (FeC12) and ferric chloride (FeCl3). Such magnetic particles are then encapsulated in biocompatible PVA to form magnetic polymer microspheres sized from 2 to 15 nm with hydroxyl groups on its surface. Cibacron Blue 3GA, a dye-ligand, was covalently coupled with the polyvinyl alcohol through the nucleophilic reaction between the chloride of its triazine ring and the hydroxyl groups of PVA molecules under alkaline condition. The affinity adsorbent carried 21.1μmol Cibacron Blue 3GA per gram magnetic polymer microspheres was used to remove unconjugated and conjugated bilirubin from the solution which was composed of bilirubin or bilirubin and protein. After the adsorption, the adsorbent loaded with bilirubin was removed easily in the magnetic field.

  16. Subband Affine Projection Algorithm for Acoustic Echo Cancellation System

    Directory of Open Access Journals (Sweden)

    Choi Hun

    2007-01-01

    Full Text Available We present a new subband affine projection (SAP algorithm for the adaptive acoustic echo cancellation with long echo path delay. Generally, the acoustic echo canceller suffers from the long echo path and large computational complexity. To solve this problem, the proposed algorithm combines merits of the affine projection (AP algorithm and the subband filtering. Convergence speed of the proposed algorithm is improved by the signal-decorrelating property of the orthogonal subband filtering and the weight updating with the prewhitened input signal of the AP algorithm. Moreover, in the proposed algorithms, as applying the polyphase decomposition, the noble identity, and the critical decimation to subband the adaptive filter, the sufficiently decomposed SAP updates the weights of adaptive subfilters without a matrix inversion. Therefore, computational complexity of the proposed method is considerably reduced. In the SAP, the derived weight updating formula for the subband adaptive filter has a simple form as ever compared with the normalized least-mean-square (NLMS algorithm. The efficiency of the proposed algorithm for the colored signal and speech signal was evaluated experimentally.

  17. Determinants of benzodiazepine brain uptake: lipophilicity versus binding affinity.

    Science.gov (United States)

    Arendt, R M; Greenblatt, D J; Liebisch, D C; Luu, M D; Paul, S M

    1987-01-01

    Factors influencing brain uptake of benzodiazepine derivatives were evaluated in adult Sprague Dawley rats (n = 8-10 per drug). Animals received single intraperitoneal doses of alprazolam, triazolam, lorazepam, flunitrazepam, diazepam, midazolam, desmethyldiazepam, or clobazam. Concentrations of each drug (and metabolites) in whole brain and serum 1 h after dosage were determined by gas chromatography. Serum free fraction was measured by equilibrium dialysis. In vitro binding affinity (apparent Ki) of each compound was estimated based on displacement of tritiated flunitrazepam in washed membrane preparations from rat cerebral cortex. Lipid solubility of each benzodiazepine was estimated using the reverse-phase liquid chromatographic (HPLC) retention index at physiologic pH. There was no significant relation between brain:total serum concentration ratio and either HPLC retention (r = 0.18) or binding Ki (r = -0.34). Correction of uptake ratios for free as opposed to total serum concentration yielded a highly significant correlation with HPLC retention (r = 0.78, P less than 0.005). However, even the corrected ratio was not correlated with binding Ki (r = -0.22). Thus a benzodiazepine's capacity to diffuse from systemic blood into brain tissue is much more closely associated with the physicochemical property of lipid solubility than with specific affinity. Unbound rather than total serum or plasma concentration most accurately reflects the quantity of drug available for diffusion. PMID:2888155

  18. Altered catecholamine receptor affinity in rabbit aortic intimal hyperplasia

    International Nuclear Information System (INIS)

    Intimal thickening is a universal response to endothelial denudation and is also thought to be a precursor of atherosclerosis. The authors have demonstrated selective supersensitivity in arterial intimal hyperplasia to norepinephrine and they now report a possible mechanism for this. Binding studies in rabbit aorta with the selective alpha 1-adrenergic radioligand 125I-HEAT demonstrated that there was no change in receptor density (20 ± 4 fmole/10(6) cells) in intact vascular smooth muscle cells at either 5 or 14 days after denudation. However, competition studies showed a 2.6-fold increase in alpha 1-adrenergic receptor affinity for norepinephrine in intimal hyperplastic tissue (P less than 0.05). This increased affinity for norepinephrine was associated with a greater increase in 32P-labeled phosphatidylinositol (148% intimal thickening versus 76% control) and phosphatidic acid (151% intimal thickening versus 56% control) following norepinephrine stimulation of free floating rings of intimal hyperplastic aorta. These data suggest that the catecholamine supersensitivity in rabbit aortic intimal hyperplasia is receptor mediated and may be linked to the phosphatidylinositol cycle

  19. Weak Affine Light Typing: Polytime intensional expressivity, soundness and completeness

    CERN Document Server

    Roversi, Luca

    2007-01-01

    Weak affine light typing (WALT) assigns light affine linear formulae as types to a subset of lambda-terms in System F. WALT is poly-time sound: if a lambda-term M has type in WALT, M can be evaluated with a polynomial cost in the dimension of the derivation that gives it a type. In particular, the evaluation can proceed under any strategy of a rewriting relation, obtained as a mix of both call-by-name/call-by-value beta-reductions. WALT is poly-time complete since it can represent any poly-time Turing machine. WALT weakens, namely generalizes, the notion of stratification of deductions common to some Light Systems -- we call as such those logical systems, derived from Linear logic, to characterize FP, the set of Polynomial functions -- . A weaker stratification allows to define a compositional embedding of the Quasi-linear fragment QlSRN of Safe recursion on notation (SRN) into WALT. QlSRN is SRN, which is a recursive-theoretical system characterizing FP, where only the composition scheme is restricted to lin...

  20. Altered catecholamine receptor affinity in rabbit aortic intimal hyperplasia

    Energy Technology Data Exchange (ETDEWEB)

    O' Malley, M.K.; Cotecchia, S.; Hagen, P.O. (Duke University Medical Center, Durham, NC (USA))

    1991-08-01

    Intimal thickening is a universal response to endothelial denudation and is also thought to be a precursor of atherosclerosis. The authors have demonstrated selective supersensitivity in arterial intimal hyperplasia to norepinephrine and they now report a possible mechanism for this. Binding studies in rabbit aorta with the selective alpha 1-adrenergic radioligand 125I-HEAT demonstrated that there was no change in receptor density (20 {plus minus} 4 fmole/10(6) cells) in intact vascular smooth muscle cells at either 5 or 14 days after denudation. However, competition studies showed a 2.6-fold increase in alpha 1-adrenergic receptor affinity for norepinephrine in intimal hyperplastic tissue (P less than 0.05). This increased affinity for norepinephrine was associated with a greater increase in 32P-labeled phosphatidylinositol (148% intimal thickening versus 76% control) and phosphatidic acid (151% intimal thickening versus 56% control) following norepinephrine stimulation of free floating rings of intimal hyperplastic aorta. These data suggest that the catecholamine supersensitivity in rabbit aortic intimal hyperplasia is receptor mediated and may be linked to the phosphatidylinositol cycle.

  1. Binding Affinity of Glycoconjugates to BACILLUS Spores and Toxins

    Science.gov (United States)

    Rasol, Aveen; Eassa, Souzan; Tarasenko, Olga

    2010-04-01

    Early recognition of Bacillus cereus group species is important since they can cause food-borne illnesses and deadly diseases in humans. Glycoconjugates (GCs) are carbohydrates covalently linked to non-sugar moieties including lipids, proteins or other entities. GCs are involved in recognition and signaling processes intrinsic to biochemical functions in cells. They also stimulate cell-cell adhesion and subsequent recognition and activation of receptors. We have demonstrated that GCs are involved in Bacillus cereus spore recognition. In the present study, we have investigated whether GCs possess the ability to bind and recognize B. cereus spores and Bacillus anthracis recombinant single toxins (sTX) and complex toxins (cTX). The affinity of GCs to spores + sTX and spores + cTX toxins was studied in the binding essay. Our results demonstrated that GC9 and GC10 were able to selectively bind to B. cereus spores and B. anthracis toxins. Different binding affinities for GCs were found toward Bacillus cereus spores + sTX and spores + cTX. Dilution of GCs does not impede the recognition and binding. Developed method provides a tool for simultaneous recognition and targeting of spores, bacteria toxins, and/or other entities.

  2. Finite-sided deformation spaces of complete affine 3-manifolds

    CERN Document Server

    Charette, Virginie; Goldman, William M

    2011-01-01

    A Margulis spacetime is a complete affine 3-manifold M with nonsolvable fundamental group. Associated to every Margulis spacetime is a noncompact complete hyperbolic surface S. We show that every Margulis spacetime is orientable, even though S may be nonorientable. We classify Margulis spacetimes when S is homeomorphic to a two-holed cross-surface, that is, the complement of two disjoint discs in the real projective plane. We show that every such manifold is homeomorphic to a solid handlebody of genus two, and admits a fundamental polyhedron bounded by crooked planes. Furthermore, the deformation space is a bundle of convex quadrilateral cones over the space of marked hyperbolic structures. The sides of each quadrilateral cone are defined by invariants of the two boundary components and the two orientation-reversing simple curves. The two-holed cross-surface, together with the three-holed sphere, are the only topologies for which the deformation space of complete affine structures is finite-sided.

  3. Affinity sensor using 3-aminophenylboronic acid for bacteria detection.

    Science.gov (United States)

    Wannapob, Rodtichoti; Kanatharana, Proespichaya; Limbut, Warakorn; Numnuam, Apon; Asawatreratanakul, Punnee; Thammakhet, Chongdee; Thavarungkul, Panote

    2010-10-15

    Boronic acid that can reversibly bind to diols was used to detect bacteria through its affinity binding reaction with diol-groups on bacterial cell walls. 3-aminophenylboronic acid (3-APBA) was immobilized on a gold electrode via a self-assembled monolayer. The change in capacitance of the sensing surface caused by the binding between 3-APBA and bacteria in a flow system was detected by a potentiostatic step method. Under optimal conditions the linear range of 1.5×10(2)-1.5×10(6) CFU ml(-1) and the detection limit of 1.0×10(2) CFU ml(-1) was obtained. The sensing surface can be regenerated and reused up to 58 times. The method was used for the analysis of bacteria in several types of water, i.e., bottled, well, tap, reservoir and wastewater. Compared with the standard plate count method, the results were within one standard deviation of each other. The proposed method can save both time and cost of analysis. The electrode modified with 3-APBA would also be applicable to the detection of other cis-diol-containing analytes. The concept could be extended to other chemoselective ligands, offering less expensive and more robust affinity sensors for a wide range of compounds. PMID:20801635

  4. Affinity purification of copper chelating peptides from chickpea protein hydrolysates.

    Science.gov (United States)

    Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

    2007-05-16

    Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals.

  5. Flexible Molybdenum Electrodes towards Designing Affinity Based Protein Biosensors.

    Science.gov (United States)

    Kamakoti, Vikramshankar; Panneer Selvam, Anjan; Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Prasad, Shalini

    2016-01-01

    Molybdenum electrode based flexible biosensor on porous polyamide substrates has been fabricated and tested for its functionality as a protein affinity based biosensor. The biosensor performance was evaluated using a key cardiac biomarker; cardiac Troponin-I (cTnI). Molybdenum is a transition metal and demonstrates electrochemical behavior upon interaction with an electrolyte. We have leveraged this property of molybdenum for designing an affinity based biosensor using electrochemical impedance spectroscopy. We have evaluated the feasibility of detection of cTnI in phosphate-buffered saline (PBS) and human serum (HS) by measuring impedance changes over a frequency window from 100 mHz to 1 MHz. Increasing changes to the measured impedance was correlated to the increased dose of cTnI molecules binding to the cTnI antibody functionalized molybdenum surface. We achieved cTnI detection limit of 10 pg/mL in PBS and 1 ng/mL in HS medium. The use of flexible substrates for designing the biosensor demonstrates promise for integration with a large-scale batch manufacturing process. PMID:27438863

  6. Expression and affinity purification of recombinant proteins from plants

    Science.gov (United States)

    Desai, Urvee A.; Sur, Gargi; Daunert, Sylvia; Babbitt, Ruth; Li, Qingshun

    2002-01-01

    With recent advances in plant biotechnology, transgenic plants have been targeted as an inexpensive means for the mass production of proteins for biopharmaceutical and industrial uses. However, the current plant purification techniques lack a generally applicable, economic, large-scale strategy. In this study, we demonstrate the purification of a model protein, beta-glucuronidase (GUS), by employing the protein calmodulin (CaM) as an affinity tag. In the proposed system, CaM is fused to GUS. In the presence of calcium, the calmodulin fusion protein binds specifically to a phenothiazine-modified surface of an affinity column. When calcium is removed with a complexing agent, e.g., EDTA, calmodulin undergoes a conformational change allowing the dissociation of the calmodulin-phenothiazine complex and, therefore, permitting the elution of the GUS-CaM fusion protein. The advantages of this approach are the fast, efficient, and economical isolation of the target protein under mild elution conditions, thus preserving the activity of the target protein. Two types of transformation methods were used in this study, namely, the Agrobacterium-mediated system and the viral-vector-mediated transformation system. Copyright 2002 Elsevier Science (USA).

  7. Impact of crystalline quality on neuronal affinity of pristine graphene.

    Science.gov (United States)

    Veliev, Farida; Briançon-Marjollet, Anne; Bouchiat, Vincent; Delacour, Cécile

    2016-04-01

    Due to its outstanding mechanical and electrical properties as well as chemical inertness, graphene has attracted a growing interest in the field of bioelectric interfacing. Herein, we investigate the suitability of pristine, i.e. without a cell adhesive coating, chemical vapor deposition (CVD) grown monolayer graphene to act as a platform for neuronal growth. We study the development of primary hippocampal neurons grown on bare graphene (transferred on glass coverslip) for up to 5 days and show that pristine graphene significantly improves the neurons adhesion and outgrowth at the early stage of culture (1-2 days in vitro). At the later development stage, neurons grown on coating free graphene (untreated with poly-L-lysine) show remarkably well developed neuritic architecture similar to those cultured on conventional poly-L-lysine coated glass coverslips. This exceptional possibility to bypass the adhesive coating allows a direct electrical contact of graphene to the cells and reveals its great potential for chronic medical implants and tissue engineering. Moreover, regarding the controversial results obtained on the neuronal affinity of pristine graphene and its ability to support neuronal growth without the need of polymer or protein coating, we found that the crystallinity of CVD grown graphene plays an important role in neuronal attachment, outgrowth and axonal specification. In particular, we show that the decreasing crystalline quality of graphene tunes the neuronal affinity from highly adhesive to fully repellent. PMID:26878439

  8. The eyes of Tullimonstrum reveal a vertebrate affinity.

    Science.gov (United States)

    Clements, Thomas; Dolocan, Andrei; Martin, Peter; Purnell, Mark A; Vinther, Jakob; Gabbott, Sarah E

    2016-04-28

    Tullimonstrum gregarium is an iconic soft-bodied fossil from the Carboniferous Mazon Creek Lagerstätte (Illinois, USA). Despite a large number of specimens and distinct anatomy, various analyses over the past five decades have failed to determine the phylogenetic affinities of the 'Tully monster', and although it has been allied to such disparate phyla as the Mollusca, Annelida or Chordata, it remains enigmatic. The nature and phylogenetic affinities of Tullimonstrum have defied confident systematic placement because none of its preserved anatomy provides unequivocal evidence of homology, without which comparative analysis fails. Here we show that the eyes of Tullimonstrum possess ultrastructural details indicating homology with vertebrate eyes. Anatomical analysis using scanning electron microscopy reveals that the eyes of Tullimonstrum preserve a retina defined by a thick sheet comprising distinct layers of spheroidal and cylindrical melanosomes. Time-of-flight secondary ion mass spectrometry and multivariate statistics provide further evidence that these microbodies are melanosomes. A range of animals have melanin in their eyes, but the possession of melanosomes of two distinct morphologies arranged in layers, forming retinal pigment epithelium, is a synapomorphy of vertebrates. Our analysis indicates that in addition to evidence of colour patterning, ecology and thermoregulation, fossil melanosomes can also carry a phylogenetic signal. Identification in Tullimonstrum of spheroidal and cylindrical melanosomes forming the remains of retinal pigment epithelium indicates that it is a vertebrate; considering its body parts in this new light suggests it was an anatomically unusual member of total group Vertebrata. PMID:27074512

  9. Fundamentals and application of ordered molecular assemblies to affinity biosensing.

    Science.gov (United States)

    Matharu, Zimple; Bandodkar, Amay Jairaj; Gupta, Vinay; Malhotra, Bansi Dhar

    2012-02-01

    Organization of biomolecules in two/three dimensional assemblies has recently aroused much interest in nanobiotechnology. In this context, the development of techniques for controlling spatial arrangement and orientation of the desired molecules to generate highly-ordered nanostructures in the form of a mono/multi layer is considered highly significant. The studies of monolayer films to date have focused on three distinct methods of preparation: (i) the Langmuir-Blodgett (LB) technique, involving the transfer of a monolayer assembled at the gas-liquid interface; (ii) self-assembly at the liquid-solid interface, based on spontaneous adsorption of desired molecules from a solution directly onto a solid surface; and (iii) Layer-by-layer (LBL) self-assembly at a liquid-solid interface, based on inter-layer electrostatic attractions for fabrication of multilayers. A variety of monolayers have been utilized to fabricate biomolecular electronic devices including biosensors. The composition of a monolayer based matrix has been found to influence the activity(ies) of biomolecule(s). We present comprehensive and critical analysis of ordered molecular assemblies formed by LB and self-assembly with potential applications to affinity biosensing. This critical review on fundamentals and application of ordered molecular assemblies to affinity biosensing is likely to benefit researchers working in this as well as related fields of research (401 references). PMID:22105315

  10. Braided affine geometry and q-analogs of wave operators

    International Nuclear Information System (INIS)

    The main goal of this review is to compare different approaches to constructing the geometry associated with a Hecke type braiding (in particular, with that related to the quantum group Uq(sl(n))). We place emphasis on the affine braided geometry related to the so-called reflection equation algebra (REA). All objects of such a type of geometry are defined in the spirit of affine algebraic geometry via polynomial relations on generators. We begin by comparing the Poisson counterparts of 'quantum varieties' and describe different approaches to their quantization. Also, we exhibit two approaches to introducing q-analogs of vector bundles and defining the Chern-Connes index for them on quantum spheres. In accordance with the Serre-Swan approach, the q-vector bundles are treated as finitely generated projective modules over the corresponding quantum algebras. Besides, we describe the basic properties of the REA used in this construction and compare different ways of defining q-analogs of partial derivatives and differentials on the REA and algebras close to them. In particular, we present a way of introducing a q-differential calculus via Koszul type complexes. The elements of the q-calculus are applied to defining q-analogs of some relativistic wave operators. (topical review)

  11. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    Science.gov (United States)

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  12. Influence of affinity on antibody determination in microtiter ELISA systems

    International Nuclear Information System (INIS)

    Theoretically, all immunoassays are affinity (Ka) dependent when the product of the antibody (Ab) Ka and the free epitope concentration is less than 10. Thus, the degree of dependence on Ka depends on the concentration of available antigen in the system. The authors examined the binding of 125I-anti-fluorescein (a-FLU) monoclonal antibodies of different affinities to FLU-gelatin adsorbed on Immunlon 2 microtiter plates. Data obtained were in general agreement with our theoretical predictions; the percent of 125I-a-FLU which bound correlated with Ka, as did the shape of the titration curves. Measurement of 5 a-FLU monoclonals by the ELISA showed that the determination of Ab concentrations depends on the FLU-gelatin concentration, epitope density, and on the relationship between the Kas of test samples and the reference standard Ab preparation. Thus the ELISA is Ka dependent and should not be used routinely to estimate the absolute amount to Ab in unknown samples. However, the Ka dependency of the ELISA might provide a convenient assay for the estimation of the relative functional Ka (rfKa) of antibody preparations

  13. Theory of affine projection algorithms for adaptive filtering

    CERN Document Server

    Ozeki, Kazuhiko

    2016-01-01

    This book focuses on theoretical aspects of the affine projection algorithm (APA) for adaptive filtering. The APA is a natural generalization of the classical, normalized least-mean-squares (NLMS) algorithm. The book first explains how the APA evolved from the NLMS algorithm, where an affine projection view is emphasized. By looking at those adaptation algorithms from such a geometrical point of view, we can find many of the important properties of the APA, e.g., the improvement of the convergence rate over the NLMS algorithm especially for correlated input signals. After the birth of the APA in the mid-1980s, similar algorithms were put forward by other researchers independently from different perspectives. This book shows that they are variants of the APA, forming a family of APAs. Then it surveys research on the convergence behavior of the APA, where statistical analyses play important roles. It also reviews developments of techniques to reduce the computational complexity of the APA, which are important f...

  14. Inhibition of lanthanide nanocrystal-induced inflammasome activation in macrophages by a surface coating peptide through abrogation of ROS production and TRPM2-mediated Ca(2+) influx.

    Science.gov (United States)

    Yao, Han; Zhang, Yunjiao; Liu, Liu; Xu, Youcui; Liu, Xi; Lin, Jun; Zhou, Wei; Wei, Pengfei; Jin, Peipei; Wen, Long-Ping

    2016-11-01

    Lanthanide-based nanoparticles (LNs) hold great promise in medicine. A variety of nanocrystals, including LNs, elicits potent inflammatory response through activation of NLRP3 inflammasome. We have previously identified an LNs-specific surface coating peptide RE-1, with the sequence of 'ACTARSPWICG', which reduced nanocrystal-cell interaction and abrogated LNs-induced autophagy and toxicity in both HeLa cells and liver hepatocytes. Here we show that RE-1 coating effectively inhibited LNs-induced inflammasome activation, mostly mediated by NLRP3, in mouse bone marrow derived macrophage (BMDM) cells, human THP-1 cells and mouse peritoneal macrophages and also reduced LNs-elicited inflammatory response in vivo. RE-1 coating had no effect on cellular internalization of LNs in BMDM cells, in contrast to the situation in HeLa cells where cell uptake of LNs was significantly inhibited by RE-1. To elucidate the molecular mechanism underlying the inflammasome-inhibiting effect of RE-1, we assessed several parameters known to influence nanocrystal-induced NLRP3 inflammasome activation. RE-1 coating did not reduce potassium efflux, which occurred after LNs treatment in BMDM cells and was necessary but insufficient for LNs-induced inflammasome activation. RE-1 did decrease lysosomal damage induced by LNs, but the inhibitor of cathepsin B did not affect LNs-elicited caspase 1 activation and IL-1β release, suggesting that lysosomal damage was not critically important for LNs-induced inflammasome activation. On the other hand, LNs-induced elevation of intracellular reactive oxygen species (ROS), critically important for inflammasome activation, was largely abolished by RE-1 coating, with the reduction on NADPH oxidase-generated ROS playing a more prominent role for RE-1's inflammasome-inhibiting effect than the reduction on mitochondria-generated ROS. ROS generation further triggered Ca(2+) influx, an event that was mediated by Transient Receptor Potential M2 (TRPM2) and was

  15. Calmodulin modulates the delay period between release of calcium from internal stores and activation of calcium influx via endogenous TRP1 channels.

    Science.gov (United States)

    Vaca, Luis; Sampieri, Alicia

    2002-11-01

    In the present study we have explored the role of calmodulin (CaM) and inositol 1,4,5-trisphosphate receptor (IP(3)R) in the communication process activated after the release of calcium from the endoplasmic reticulum (ER) and the activation of calcium influx via endogenous TRP1 channels from Chinese hamster ovary cells. Experiments using combined rapid confocal calcium and electrophysiology measurements uncovered a consistent delay of around 900 ms between the first detectable calcium released from the ER and the activation of the calcium current. This delay was evident with two different methods used to release calcium from the ER: either the blockade of the microsomal calcium ATPase with thapsigargin or activation of bradykinin receptors linked to the IP(3) cascade. Direct application of IP(3) or a peptide from the NH(2)-terminal region of the IP(3)R activated store operated calcium, reducing the delay period. Introduction of CaM into the cell via the patch pipette increased the delay period from 900 +/- 100 ms to 10 +/- 2.1 s (n = 18). Furthermore, the use of selective CaM antagonists W7 and trifluoperazine maleate resulted in a substantial reduction of the delay period to 200 +/- 100 ms with 5 microm trifluoperazine maleate (n = 16) and 150 +/- 50 ms with 500 nm W7 (n = 22). CaM reduced also the current density activated by thapsigargin or brandykinin to about 60% from control. The CaM antagonists did not affect significantly the current density. The results presented here are consistent with an antagonistic effect of IP(3)R and CaM for the activation of store operated calcium after depletion of the ER. The functional competition between the activating effect of IP(3)R and the inhibiting effect of CaM may modulate the delay period between the release of calcium from the ER and the activation of calcium influx observed in different cells, as well as the amount of current activated after depletion of the ER.

  16. P2X7 receptor activation downmodulates Na(+)-dependent high-affinity GABA and glutamate transport into rat brain cortex synaptosomes.

    Science.gov (United States)

    Barros-Barbosa, A R; Lobo, M G; Ferreirinha, F; Correia-de-Sá, P; Cordeiro, J M

    2015-10-15

    Sodium-dependent high-affinity amino-acid transporters play crucial roles in terminating synaptic transmission in the central nervous system (CNS). However, there is lack of information about the mechanisms underlying the regulation of amino-acid transport by fast-acting neuromodulators, like ATP. Here, we investigated whether activation of the ATP-sensitive P2X7 receptor modulates Na(+)-dependent high-affinity γ-aminobutyric acid (GABA) and glutamate uptake into nerve terminals (synaptosomes) of the rat cerebral cortex. Radiolabeled neurotransmitter accumulation was evaluated by liquid scintillation spectrometry. The cell-permeant sodium-selective fluorescent indicator, SBFI-AM, was used to estimate Na(+) influx across plasma membrane. 2'(3')-O-(4-benzoylbenzoyl)ATP (BzATP, 3-300 μM), a prototypic P2X7 receptor agonist, concentration-dependently decreased [(3)H]GABA (14%) and [(14)C]glutamate (24%) uptake; BzATP decreased transport maximum velocity (Vmax) without affecting the Michaelis constant (Km) values. The selective P2X7 receptor antagonist, A-438079 (3 μM), prevented inhibition of [(3)H]GABA and [(14)C]glutamate uptake by BzATP (100 μM). The inhibitory effect of BzATP coincided with its ability to increase intracellular Na(+) and was mimicked by Na(+) ionophores, like gramicidin and monensin. Increases in intracellular Na(+) (with veratridine or ouabain) or substitution of extracellular Na(+) by N-methyl-D-glucamine (NMDG)(+) all decreased [(3)H]GABA and [(14)C]glutamate uptake and attenuated BzATP effects. Uptake inhibition by BzATP (100 μM) was also attenuated by calmidazolium, which selectively inhibits Na(+) currents through the P2X7 receptor pore. In conclusion, disruption of the Na(+) gradient by P2X7 receptor activation downmodulates high-affinity GABA and glutamate uptake into rat cortical synaptosomes. Interference with amino-acid transport efficacy may constitute a novel target for therapeutic management of cortical excitability. PMID

  17. A thermal responsive affinity ligand for precipitation of sialylated proteins

    Directory of Open Access Journals (Sweden)

    Lindsay Arnold

    2016-01-01

    Full Text Available We report here the development of a thermal responsive affinity ligand specific to sialic acid, sialic acid containing oligosaccharides, glycoproteins, and other sialylated glycoconjugates. The ligand is a fusion protein of 40 repeats of pentapeptide of an elastin like polymer (ELP and the 21 kD sialic acid binding domain of a Vibrio cholera neuraminidase (VCNA. For cost-effective synthesis, the fusion protein was targeted to the periplasmic space of an E. coli lpp deletion mutant, resulting in its secretion to the growth medium. A pre-induction heat-shock step at 42 ˚C for 20 minutes was necessary to achieve high level expression of the ligand. Under optimized induction condition (18 ˚C, 0.1 mM IPTG and 48 hours of post-induction cultivation, the ligand was produced to about 100 mg/L. The ligand exhibited a transition temperature of 52 ˚C, which could be depressed to 37 ˚C with the addition of 0.5 M NaCl. Using fetuin as a model sialylated protein, the ligand was applied in an affinity precipitation process to illustrate its potential application in glycoprotein isolation. The ligand captured 100% fetuin from an aqueous solution when the molar ratio of ligand to fetuin was 10 to 1, which was lower than the expected for full titration of sialic acid on the glycoprotein by the lectin. Elution of fetuin from ligand was achieved with PBS buffer containing 2 mM sialic acid. To evaluate how protein and other contaminants influence the recovery of sialylated proteins, CHO medium was spiked into the fetuin solution. The predominant protein species in CHO medium was found to be albumin. Although its removal of over 94% was evident, purified fetuin contained some albumin due to its over-abundance. Additional experiments with albumin contaminant of varying concentrations showed that below 1 mg/L, albumin had no impact on the affinity precipitation, whereas above 10 mg/L, some albumin was co-purified with fetuin. However, even at 50 mg/ml, fetuin

  18. TRPM8 and Nav1.8 sodium channels are required for transthyretin-induced calcium influx in growth cones of small-diameter TrkA-positive sensory neurons

    Directory of Open Access Journals (Sweden)

    Vincent Adele J

    2011-03-01

    Full Text Available Abstract Background Familial amyloidotic polyneuropathy (FAP is a peripheral neuropathy caused by the extracellular accumulation and deposition of insoluble transthyretin (TTR aggregates. However the molecular mechanism that underlies TTR toxicity in peripheral nerves is unclear. Previous studies have suggested that amyloidogenic proteins can aggregate into oligomers which disrupt intracellular calcium homeostasis by increasing the permeability of the plasma membrane to extracellular calcium. The aim of the present study was to examine the effect of TTR on calcium influx in dorsal root ganglion neurons. Results Levels of intracellular cytosolic calcium were monitored in dorsal root ganglion (DRG neurons isolated from embryonic rats using the calcium-sensitive fluorescent indicator Fluo4. An amyloidogenic mutant form of TTR, L55P, induced calcium influx into the growth cones of DRG neurons, whereas wild-type TTR had no significant effect. Atomic force microscopy and dynamic light scattering studies confirmed that the L55P TTR contained oligomeric species of TTR. The effect of L55P TTR was decreased by blockers of voltage-gated calcium channels (VGCC, as well as by blockers of Nav1.8 voltage-gated sodium channels and transient receptor potential M8 (TRPM8 channels. siRNA knockdown of TRPM8 channels using three different TRPM8 siRNAs strongly inhibited calcium influx in DRG growth cones. Conclusions These data suggest that activation of TRPM8 channels triggers the activation of Nav1.8 channels which leads to calcium influx through VGCC. We suggest that TTR-induced calcium influx into DRG neurons may contribute to the pathophysiology of FAP. Furthermore, we speculate that similar mechanisms may mediate the toxic effects of other amyloidogenic proteins such as the β-amyloid protein of Alzheimer's disease.

  19. Minimal free resolutions for certain affine monomial curve

    CERN Document Server

    Gimenez, Philippe; Srinivasan, Hema

    2010-01-01

    Given an arbitrary field k and an arithmetic sequence of positive integers m_0<...affine monomial curve parameterized by X_0=t^{m_0},...,X_n=t^{m_n}. In this paper, we conjecture that the Betti numbers of its coordinate ring are completely determined by n and the value of m_0 modulo n. We first show that the defining ideal of the monomial curve can be written as a sum of two determinantal ideals. Using this fact, we describe the minimal free resolution of the coordinate ring in the following three cases: when m_0 is 1 modulo n (determinantal), when m_0 is n modulo n (almost determinantal), and when m_0 is 2 modulo n and n=4 (Gorenstein of codimension 4).

  20. The metric-affine formalism of f(R) gravity

    International Nuclear Information System (INIS)

    Recently a class of alternative theories of gravity which goes under the name f(R) gravity, has received considerable attention, mainly due to its interesting applications in cosmology. However, the phenomenology of such theories is not only relevant to cosmological scales, especially when it is treated within the framework of the so called Palatini variation, an independent variation with respect to the metric and the connection, which is not considered a priori to be the Levi-Civita connection of the metric. If this connection has its standard geometrical meaning the resulting theory will be a metric-affine theory of gravity, as will be discussed in this talk. The general formalism will be presented and several aspects of the theory will be covered, mainly focusing on the enriched phenomenology that such theories exhibit with respect to General Relativity, relevant not only to large scales (cosmology) but also to small scales (e.g. torsion)

  1. Approximated affine projection algorithm for feedback cancellation in hearing aids.

    Science.gov (United States)

    Lee, Sangmin; Kim, In-Young; Park, Young-Cheol

    2007-09-01

    We propose an approximated affine projection (AP) algorithm for feedback cancellation in hearing aids. It is based on the conventional approach using the Gauss-Seidel (GS) iteration, but provides more stable convergence behaviour even with small step sizes. In the proposed algorithm, a residue of the weighted error vector, instead of the current error sample, is used to provide stable convergence. A new learning rate control scheme is also applied to the proposed algorithm to prevent signal cancellation and system instability. The new scheme determines step size in proportion to the prediction factor of the input, so that adaptation is inhibited whenever tone-like signals are present in the input. Simulation results verified the efficiency of the proposed algorithm. PMID:17644214

  2. Affine generalizations of gravity in the light of modern cosmology

    CERN Document Server

    Filippov, A T

    2010-01-01

    We discuss new models of an `affine' theory of gravity in multidimensional space-times with symmetric connections. We use and develop ideas of Weyl, Eddington, and Einstein, in particular, Einstein's proposal to specify the space - time geometry by use of the Hamilton principle. More specifically, the connection coefficients are determined using a `geometric' Lagrangian that is an arbitrary function of the generalized (non-symmetric) Ricci curvature tensor (and, possibly, of other fundamental tensors) expressed in terms of the connection coefficients regarded as independent variables. Such a theory supplements the standard Einstein gravity with dark energy (the cosmological constant, in the first approximation), a neutral massive (or tachyonic) vector field (vecton), and massive (or tachyonic) scalar fields. These fields couple only to gravity and can generate dark matter and/or inflation. The new field masses (real or imaginary) have a geometric origin and must appear in any concrete model. The concrete choi...

  3. Affinity sensor based on immobilized molecular imprinted synthetic recognition elements.

    Science.gov (United States)

    Lenain, Pieterjan; De Saeger, Sarah; Mattiasson, Bo; Hedström, Martin

    2015-07-15

    An affinity sensor based on capacitive transduction was developed to detect a model compound, metergoline, in a continuous flow system. This system simulates the monitoring of low-molecular weight organic compounds in natural flowing waters, i.e. rivers and streams. During operation in such scenarios, control of the experimental parameters is not possible, which poses a true analytical challenge. A two-step approach was used to produce a sensor for metergoline. Submicron spherical molecularly imprinted polymers, used as recognition elements, were obtained through emulsion polymerization and subsequently coupled to the sensor surface by electropolymerization. This way, a robust and reusable sensor was obtained that regenerated spontaneously under the natural conditions in a river. Small organic compounds could be analyzed in water without manipulating the binding or regeneration conditions, thereby offering a viable tool for on-site application. PMID:25703726

  4. Genetic affinities of Ukrainians from the maternal perspective.

    Science.gov (United States)

    Pshenichnov, Andrey; Balanovsky, Oleg; Utevska, Olga; Metspalu, Ene; Zaporozhchenko, Valery; Agdzhoyan, Anastasia; Churnosov, Mikhail; Atramentova, Lyubov; Balanovska, Elena

    2013-12-01

    The area of what is now the Ukraine has been the arena of large-scale demographic processes that may have left their traces in the contemporary gene pool of Ukrainians. In this study, we present new mitochondrial DNA data for 607 Ukrainians (hypervariable segment I sequences and coding region polymorphisms). To study the maternal affinities of Ukrainians at the level of separate mitochondrial haplotypes, we apply an original technique, the haplotype co-occurrence analysis. About 20% of the Ukrainian maternal gene pool is represented by lineages highly specific to Ukrainians, but is scarcely found in other populations. About 9% of Ukrainian mtDNA lineages are typical for peoples of the Volga region. We also identified minor gene pool strata (1.6-3.3%), each of which is common in Lithuanians, Estonians, Saami, Nenets, Cornish, and the populations of the North Caucasus.

  5. The Eigenvalue Problem for Linear and Affine Iterated Function Systems

    CERN Document Server

    Barnsley, Michael

    2010-01-01

    The eigenvalue problem for a linear function L centers on solving the eigen-equation Lx = rx. This paper generalizes the eigenvalue problem from a single linear function to an iterated function system F consisting of possibly an infinite number of linear or affine functions. The eigen-equation becomes F(X) = rX, where r>0 is real, X is a compact set, and F(X)is the union of f(X), for f in F. The main result is that an irreducible, linear iterated function system F has a unique eigenvalue r equal to the joint spectral radius of the functions in F and a corresponding eigenset S that is centrally symmetric, star-shaped, and full dimensional. Results of Barabanov and of Dranishnikov-Konyagin-Protasov on the joint spectral radius follow as corollaries.

  6. Political ideology: its structure, functions, and elective affinities.

    Science.gov (United States)

    Jost, John T; Federico, Christopher M; Napier, Jaime L

    2009-01-01

    Ideology has re-emerged as an important topic of inquiry among social, personality, and political psychologists. In this review, we examine recent theory and research concerning the structure, contents, and functions of ideological belief systems. We begin by defining the construct and placing it in historical and philosophical context. We then examine different perspectives on how many (and what types of) dimensions individuals use to organize their political opinions. We investigate (a) how and to what extent individuals acquire the discursive contents associated with various ideologies, and (b) the social-psychological functions that these ideologies serve for those who adopt them. Our review highlights "elective affinities" between situational and dispositional needs of individuals and groups and the structure and contents of specific ideologies. Finally, we consider the consequences of ideology, especially with respect to attitudes, evaluations, and processes of system justification. PMID:19035826

  7. Boundaries of Disk-like Self-affine Tiles

    CERN Document Server

    Leung, King-Shun

    2012-01-01

    Let $T:= T(A, {\\mathcal D})$ be a disk-like self-affine tile generated by an integral expanding matrix $A$ and a consecutive collinear digit set ${\\mathcal D}$, and let $f(x)=x^{2}+px+q$ be the characteristic polynomial of $A$. By investigating the neighbors of $T$, we construct a neighbor graph and show that any point on the boundary $\\partial T$ can be identified with a one-sided infinite path of the graph. Also we derive certain equivalent conditions for the pair $(A,{\\mathcal D})$ to be a number system. From the neighbor graph we can deduce a family of graph-directed sets, which gives a second description of $\\partial T$. When $A$ is a similarity, we obtain $\\dim_H (\\partial T)=2\\log \\rho/\\log |q|$ where $\\rho$ is the largest positive zero of the cubic polynomial $x^{3}-(|p|-1)x^{2}-(|q|-|p|)x-|q|$.

  8. Electron Affinities of the Early Lanthanide Monoxide Molecules

    Institute of Scientific and Technical Information of China (English)

    Chao-xian Chi; Hua Xie; Ran Cong; Zi-chao Tang; Ming-fei Zhou

    2011-01-01

    The photoelectron imagings of LaO-,CeO-,PRO-,and NdO- at 1064 nm are reported.The well resolved photoelectron spectra allow the electron affinities to be determined as 0.99(1) eV for LaO,1.00(1) eV for CeO,1.00(1) eV for PrO,and 1.01(1) eV for NdO,respectively.Density functional calculations and natural atomic orbital analyses show that the 4f electrons tend to be localized and suffer little from the charge states of the molecules.The photodetached electron mainly originates from the 6s orbital of the metals.The ligand field theory with the δ=2 assumption is still an effective method to analyze the ground states of the neutral and anionic lanthanide monoxides.

  9. Optimal growth for linear processes with affine control

    CERN Document Server

    Calvez, Vincent

    2012-01-01

    We analyse an optimal control with the following features: the dynamical system is linear, and the dependence upon the control parameter is affine. More precisely we consider $\\dot x_\\alpha(t) = (G + \\alpha(t) F)x_\\alpha(t)$, where $G$ and $F$ are $3\\times 3$ matrices with some prescribed structure. In the case of constant control $\\alpha(t)\\equiv \\alpha$, we show the existence of an optimal Perron eigenvalue with respect to varying $\\alpha$ under some assumptions. Next we investigate the Floquet eigenvalue problem associated to time-periodic controls $\\alpha(t)$. Finally we prove the existence of an eigenvalue (in the generalized sense) for the optimal control problem. The proof is based on the results by [Arisawa 1998, Ann. Institut Henri Poincar\\'e] concerning the ergodic problem for Hamilton-Jacobi equations. We discuss the relations between the three eigenvalues. Surprisingly enough, the three eigenvalues appear to be numerically the same.

  10. Deformation of supersymmetric and conformal quantum mechanics through affine transformations

    Science.gov (United States)

    Spiridonov, Vyacheslav

    1993-01-01

    Affine transformations (dilatations and translations) are used to define a deformation of one-dimensional N = 2 supersymmetric quantum mechanics. Resulting physical systems do not have conserved charges and degeneracies in the spectra. Instead, superpartner Hamiltonians are q-isospectral, i.e. the spectrum of one can be obtained from another (with possible exception of the lowest level) by q(sup 2)-factor scaling. This construction allows easily to rederive a special self-similar potential found by Shabat and to show that for the latter a q-deformed harmonic oscillator algebra of Biedenharn and Macfarlane serves as the spectrum generating algebra. A general class of potentials related to the quantum conformal algebra su(sub q)(1,1) is described. Further possibilities for q-deformation of known solvable potentials are outlined.

  11. Higher Order Kernels and Locally Affine LDDMM Registration

    CERN Document Server

    Sommer, Stefan; Darkner, Sune; Pennec, Xavier

    2011-01-01

    To achieve sparse description that allows intuitive analysis, we aim to represent deformation with a basis containing interpretable elements, and we wish to use elements that have the description capacity to represent the deformation compactly. We accomplish this by introducing higher order kernels in the LDDMM registration framework. The kernels allow local description of affine transformations and subsequent compact description of non-translational movement and of the entire non-rigid deformation. This is obtained with a representation that contains directly interpretable information from both mathematical and modeling perspectives. We develop the mathematical construction behind the higher order kernels, we show the implications for sparse image registration and deformation description, and we provide examples of how the capacity of the kernels enables registration with a very low number of parameters. The capacity and interpretability of the kernels lead to natural modeling of articulated movement, and th...

  12. An Affinity Propagation-Based DNA Motif Discovery Algorithm.

    Science.gov (United States)

    Sun, Chunxiao; Huo, Hongwei; Yu, Qiang; Guo, Haitao; Sun, Zhigang

    2015-01-01

    The planted (l, d) motif search (PMS) is one of the fundamental problems in bioinformatics, which plays an important role in locating transcription factor binding sites (TFBSs) in DNA sequences. Nowadays, identifying weak motifs and reducing the effect of local optimum are still important but challenging tasks for motif discovery. To solve the tasks, we propose a new algorithm, APMotif, which first applies the Affinity Propagation (AP) clustering in DNA sequences to produce informative and good candidate motifs and then employs Expectation Maximization (EM) refinement to obtain the optimal motifs from the candidate motifs. Experimental results both on simulated data sets and real biological data sets show that APMotif usually outperforms four other widely used algorithms in terms of high prediction accuracy.

  13. An Affinity Propagation-Based DNA Motif Discovery Algorithm

    Directory of Open Access Journals (Sweden)

    Chunxiao Sun

    2015-01-01

    Full Text Available The planted (l,d motif search (PMS is one of the fundamental problems in bioinformatics, which plays an important role in locating transcription factor binding sites (TFBSs in DNA sequences. Nowadays, identifying weak motifs and reducing the effect of local optimum are still important but challenging tasks for motif discovery. To solve the tasks, we propose a new algorithm, APMotif, which first applies the Affinity Propagation (AP clustering in DNA sequences to produce informative and good candidate motifs and then employs Expectation Maximization (EM refinement to obtain the optimal motifs from the candidate motifs. Experimental results both on simulated data sets and real biological data sets show that APMotif usually outperforms four other widely used algorithms in terms of high prediction accuracy.

  14. A High-Affinity Adenosine Kinase from Anopheles Gambiae

    Energy Technology Data Exchange (ETDEWEB)

    M Cassera; M Ho; E Merino; E Burgos; A Rinaldo-Matthis; S Almo; V Schramm

    2011-12-31

    Genome analysis revealed a mosquito orthologue of adenosine kinase in Anopheles gambiae (AgAK; the most important vector for the transmission of Plasmodium falciparum in Africa). P. falciparum are purine auxotrophs and do not express an adenosine kinase but rely on their hosts for purines. AgAK was kinetically characterized and found to have the highest affinity for adenosine (K{sub m} = 8.1 nM) of any known adenosine kinase. AgAK is specific for adenosine at the nucleoside site, but several nucleotide triphosphate phosphoryl donors are tolerated. The AgAK crystal structure with a bound bisubstrate analogue Ap{sub 4}A (2.0 {angstrom} resolution) reveals interactions for adenosine and ATP and the geometry for phosphoryl transfer. The polyphosphate charge is partly neutralized by a bound Mg{sup 2+} ion and an ion pair to a catalytic site Arg. The AgAK structure consists of a large catalytic core in a three-layer {alpha}/{beta}/{alpha} sandwich, and a small cap domain in contact with adenosine. The specificity and tight binding for adenosine arise from hydrogen bond interactions of Asn14, Leu16, Leu40, Leu133, Leu168, Phe168, and Thr171 and the backbone of Ile39 and Phe168 with the adenine ring as well as through hydrogen bond interactions between Asp18, Gly64, and Asn68 and the ribosyl 2'- and 3'-hydroxyl groups. The structure is more similar to that of human adenosine kinase (48% identical) than to that of AK from Toxoplasma gondii (31% identical). With this extraordinary affinity for AgAK, adenosine is efficiently captured and converted to AMP at near the diffusion limit, suggesting an important role for this enzyme in the maintenance of the adenine nucleotide pool. mRNA analysis verifies that AgAK transcripts are produced in the adult insects.

  15. Changing water affinity from hydrophobic to hydrophilic in hydrophobic channels.

    Science.gov (United States)

    Ohba, Tomonori; Yamamoto, Shotaro; Kodaira, Tetsuya; Hata, Kenji

    2015-01-27

    The behavior of water at hydrophobic interfaces can play a significant role in determining chemical reaction outcomes and physical properties. Carbon nanotubes and aluminophosphate materials have one-dimensional hydrophobic channels, which are entirely surrounded by hydrophobic interfaces. Unique water behavior was observed in such hydrophobic channels. In this article, changes in the water affinity in one-dimensional hydrophobic channels were assessed using water vapor adsorption isotherms at 303 K and grand canonical Monte Carlo simulations. Hydrophobic behavior of water adsorbed in channels wider than 3 nm was observed for both adsorption and desorption processes, owing to the hydrophobic environment. However, water showed hydrophilic properties in both adsorption and desorption processes in channels narrower than 1 nm. In intermediate-sized channels, the hydrophobic properties of water during the adsorption process were seen to transition to hydrophilic behavior during the desorption process. Hydrophilic properties in the narrow channels for both adsorption and desorption processes are a result of the relatively strong water-channel interactions (10-15 kJ mol(-1)). In the 2-3 nm channels, the water-channel interaction energy of 4-5 kJ mol(-1) was comparable to the thermal translational energy. The cohesive water interaction was approximately 35 kJ mol(-1), which was larger than the others. Thus, the water affinity change in the 2-3 nm channels for the adsorption and desorption processes was attributed to weak water-channel interactions and strong cohesive interactions. These results are inherently important to control the properties of water in hydrophobic environments.

  16. Rejuvenation of metallic glasses by non-affine thermal strain.

    Science.gov (United States)

    Ketov, S V; Sun, Y H; Nachum, S; Lu, Z; Checchi, A; Beraldin, A R; Bai, H Y; Wang, W H; Louzguine-Luzgin, D V; Carpenter, M A; Greer, A L

    2015-08-13

    When a spatially uniform temperature change is imposed on a solid with more than one phase, or on a polycrystal of a single, non-cubic phase (showing anisotropic expansion-contraction), the resulting thermal strain is inhomogeneous (non-affine). Thermal cycling induces internal stresses, leading to structural and property changes that are usually deleterious. Glasses are the solids that form on cooling a liquid if crystallization is avoided--they might be considered the ultimate, uniform solids, without the microstructural features and defects associated with polycrystals. Here we explore the effects of cryogenic thermal cycling on glasses, specifically metallic glasses. We show that, contrary to the null effect expected from uniformity, thermal cycling induces rejuvenation, reaching less relaxed states of higher energy. We interpret these findings in the context that the dynamics in liquids become heterogeneous on cooling towards the glass transition, and that there may be consequent heterogeneities in the resulting glasses. For example, the vibrational dynamics of glassy silica at long wavelengths are those of an elastic continuum, but at wavelengths less than approximately three nanometres the vibrational dynamics are similar to those of a polycrystal with anisotropic grains. Thermal cycling of metallic glasses is easily applied, and gives improvements in compressive plasticity. The fact that such effects can be achieved is attributed to intrinsic non-uniformity of the glass structure, giving a non-uniform coefficient of thermal expansion. While metallic glasses may be particularly suitable for thermal cycling, the non-affine nature of strains in glasses in general deserves further study, whether they are induced by applied stresses or by temperature change.

  17. Proton and sodium cation affinities of harpagide: a computational study.

    Science.gov (United States)

    Colas, Cyril; Bouchonnet, Stéphane; Rogalewicz-Gilard, Françoise; Popot, Marie-Agnès; Ohanessian, Gilles

    2006-06-15

    The aim of this work was to estimate the proton and sodium cation affinities of harpagide (Har), an iridoid glycoside responsible for the antiinflammatory properties of the medicinal plant Harpagophytum. Monte Carlo conformational searches were performed at the semiempirical AM1 level to determine the most stable conformers for harpagide and its protonated and Na+-cationized forms. The 10 oxygen atoms of the molecule were considered as possible protonation and cationization sites. Geometry optimizations were then refined at the DFT B3LYP/6-31G level from the geometries of the most stable conformers found. Final energetics were obtained at the B3LYP/6-311+G(2d,2p)//B3LYP/6-31G level. The proton and sodium ion affinities of harpagide have been estimated at 223.5 and 66.0 kcal/mol, respectively. Since harpagide mainly provides HarNa+ ions in electrospray experiments, the DeltarG298 associated with the reaction of proton/sodium exchange between Har and methanol, MeOHNa+ + HarH+ --> MeOH2+ + HarNa+ (1), has been calculated; it has been estimated to be 1.9 kcal/mol. Complexing a methanol molecule to each reagent and product of reaction 1 makes the reaction become exothermic by 1.7 kcal/mol. These values are in the limit of the accuracy of the method and do not allow us to conclude definitely whether the reaction is endo- or exothermic, but, according to these very small values, the cation exchange reaction is expected to proceed easily in the final stages of the ion desolvation process. PMID:16759142

  18. Electron affinity of cubic boron nitride terminated with vanadium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yu; Sun, Tianyin; Shammas, Joseph; Hao, Mei; Nemanich, Robert J. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Kaur, Manpuneet [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287-6106 (United States)

    2015-10-28

    A thermally stable negative electron affinity (NEA) for a cubic boron nitride (c-BN) surface with vanadium-oxide-termination is achieved, and its electronic structure was analyzed with in-situ photoelectron spectroscopy. The c-BN films were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition employing BF{sub 3} and N{sub 2} as precursors. Vanadium layers of ∼0.1 and 0.5 nm thickness were deposited on the c-BN surface in an electron beam deposition system. Oxidation of the metal layer was achieved by an oxygen plasma treatment. After 650 °C thermal annealing, the vanadium oxide on the c-BN surface was determined to be VO{sub 2}, and the surfaces were found to be thermally stable, exhibiting an NEA. In comparison, the oxygen-terminated c-BN surface, where B{sub 2}O{sub 3} was detected, showed a positive electron affinity of ∼1.2 eV. The B{sub 2}O{sub 3} evidently acts as a negatively charged layer introducing a surface dipole directed into the c-BN. Through the interaction of VO{sub 2} with the B{sub 2}O{sub 3} layer, a B-O-V layer structure would contribute a dipole between the O and V layers with the positive side facing vacuum. The lower enthalpy of formation for B{sub 2}O{sub 3} is favorable for the formation of the B-O-V layer structure, which provides a thermally stable surface dipole and an NEA surface.

  19. Development and characterization of high affinity leptins and leptin antagonists.

    Science.gov (United States)

    Shpilman, Michal; Niv-Spector, Leonora; Katz, Meirav; Varol, Chen; Solomon, Gili; Ayalon-Soffer, Michal; Boder, Eric; Halpern, Zamir; Elinav, Eran; Gertler, Arieh

    2011-02-11

    Leptin is a pleiotropic hormone acting both centrally and peripherally. It participates in a variety of biological processes, including energy metabolism, reproduction, and modulation of the immune response. So far, structural elements affecting leptin binding to its receptor remain unknown. We employed random mutagenesis of leptin, followed by selection of high affinity mutants by yeast surface display and discovered that replacing residue Asp-23 with a non-negatively charged amino acid leads to dramatically enhanced affinity of leptin for its soluble receptor. Rational mutagenesis of Asp-23 revealed the D23L substitution to be most effective. Coupling the Asp-23 mutation with alanine mutagenesis of three amino acids (L39A/D40A/F41A) previously reported to convert leptin into antagonist resulted in potent antagonistic activity. These novel superactive mouse and human leptin antagonists (D23L/L39A/D40A/F41A), termed SMLA and SHLA, respectively, exhibited over 60-fold increased binding to leptin receptor and 14-fold higher antagonistic activity in vitro relative to the L39A/D40A/F41A mutants. To prolong and enhance in vivo activity, SMLA and SHLA were monopegylated mainly at the N terminus. Administration of the pegylated SMLA to mice resulted in a remarkably rapid, significant, and reversible 27-fold more potent increase in body weight (as compared with pegylated mouse leptin antagonist), because of increased food consumption. Thus, recognition and mutagenesis of Asp-23 enabled construction of novel compounds that induce potent and reversible central and peripheral leptin deficiency. In addition to enhancing our understanding of leptin interactions with its receptor, these antagonists enable in vivo study of the role of leptin in metabolic and immune processes and hold potential for future therapeutic use in disease pathologies involving leptin.

  20. Development and Characterization of High Affinity Leptins and Leptin Antagonists*

    Science.gov (United States)

    Shpilman, Michal; Niv-Spector, Leonora; Katz, Meirav; Varol, Chen; Solomon, Gili; Ayalon-Soffer, Michal; Boder, Eric; Halpern, Zamir; Elinav, Eran; Gertler, Arieh

    2011-01-01

    Leptin is a pleiotropic hormone acting both centrally and peripherally. It participates in a variety of biological processes, including energy metabolism, reproduction, and modulation of the immune response. So far, structural elements affecting leptin binding to its receptor remain unknown. We employed random mutagenesis of leptin, followed by selection of high affinity mutants by yeast surface display and discovered that replacing residue Asp-23 with a non-negatively charged amino acid leads to dramatically enhanced affinity of leptin for its soluble receptor. Rational mutagenesis of Asp-23 revealed the D23L substitution to be most effective. Coupling the Asp-23 mutation with alanine mutagenesis of three amino acids (L39A/D40A/F41A) previously reported to convert leptin into antagonist resulted in potent antagonistic activity. These novel superactive mouse and human leptin antagonists (D23L/L39A/D40A/F41A), termed SMLA and SHLA, respectively, exhibited over 60-fold increased binding to leptin receptor and 14-fold higher antagonistic activity in vitro relative to the L39A/D40A/F41A mutants. To prolong and enhance in vivo activity, SMLA and SHLA were monopegylated mainly at the N terminus. Administration of the pegylated SMLA to mice resulted in a remarkably rapid, significant, and reversible 27-fold more potent increase in body weight (as compared with pegylated mouse leptin antagonist), because of increased food consumption. Thus, recognition and mutagenesis of Asp-23 enabled construction of novel compounds that induce potent and reversible central and peripheral leptin deficiency. In addition to enhancing our understanding of leptin interactions with its receptor, these antagonists enable in vivo study of the role of leptin in metabolic and immune processes and hold potential for future therapeutic use in disease pathologies involving leptin. PMID:21119198

  1. Neuroprotective Effect of Puerarin on Glutamate-Induced Cytotoxicity in Differentiated Y-79 Cells via Inhibition of ROS Generation and Ca(2+) Influx.

    Science.gov (United States)

    Wang, Ke; Zhu, Xue; Zhang, Kai; Wu, Zhifeng; Sun, Song; Zhou, Fanfan; Zhu, Ling

    2016-01-01

    Glutamate toxicity is estimated to be the key cause of photoreceptor degeneration in the pathogenesis of retinal degenerative diseases. Oxidative stress and Ca(2+) influx induced by glutamate are responsible for the apoptosis process of photoreceptor degeneration. Puerarin, a primary component of Kudzu root, has been widely used in the clinical treatment of retinal degenerative diseases in China for decades; however, the detailed molecular mechanism underlying this effect remains unclear. In this study, the neuroprotective effect of puerarin against glutamate-induced cytotoxicity in the differentiated Y-79 cells was first investigated through cytotoxicity assay. Then the molecular mechanism of this effect regarding anti-oxidative stress and Ca(2+) hemostasis was further explored with indirect immunofluorescence, flow cytometric analysis and western blot analysis. Our study showed that glutamate induced cell viability loss, excessive reactive oxygen species (ROS) generation, calcium overload and up-regulated cell apoptosis in differentiated Y-79 cells, which effect was significantly attenuated with the pre-treatment of puerarin in a dose-dependent manner. Furthermore, our data indicated that the neuroprotective effect of puerarin was potentially mediated through the inhibition of glutamate-induced activation of mitochondrial-dependent signaling pathway and calmodulin-dependent protein kinase II (CaMKII)-dependent apoptosis signal-regulating kinase 1(ASK-1)/c-Jun N-terminal kinase (JNK)/p38 signaling pathway. The present study supports the notion that puerarin may be a promising neuroprotective agent in the prevention of retinal degenerative diseases. PMID:27409614

  2. Yeast Ca(2+)-signal transduction inhibitors isolated from Dominican amber prevent the degranulation of RBL-2H3 cells through the inhibition of Ca(2+)-influx.

    Science.gov (United States)

    Abe, Tomomi; Kobayashi, Miki; Okawa, Yusuke; Inui, Tomoki; Yoshida, Jun; Higashio, Hironori; Shinden, Hisao; Uesugi, Shota; Koshino, Hiroyuki; Kimura, Ken-Ichi

    2016-09-01

    A new norlabdane compound, named kujigamberol has previously been isolated from Kuji amber (but not from Baltic amber) by activity guided fractionation. However, there has been no study of biological compounds in Dominican amber. Biological activities were examined using the hypersensitive mutant yeast (zds1Δ erg3Δ pdr1Δ pdr3Δ) with respect to Ca(2+)-signal transduction, enzymes and rat basophilic leukemia (RBL)-2H3 cells. The structures were elucidated on the basis of spectral analysis including high resolution (HR)-EI-MS, 1D NMR and 2D NMR. Three diterpenoid compounds, 5(10)-halimen-15-oic acid (1), 3-cleroden-15-oic acid (2) and 8-labden-15-oic acid (3), which are different from the bioactive compounds in Kuji and Baltic ambers, were isolated from Dominican amber. They inhibited both calcineurin (CN) (IC50=40.0, 21.2 and 34.2μM) and glycogen synthase kinase-3β (GSK-3β) (IC50=48.9, 43.8 and 41.1μM) which are involved in the growth restored activity against the mutant yeast. The most abundant compound 2 showed inhibitory activity against both degranulation and Ca(2+)-influx in RBL-2H3 cells. The compounds having the growth restoring activity against the mutant yeast have potential as anti-allergic compounds.

  3. Capsaicin sensitizes TRAIL-induced apoptosis through Sp1-mediated DR5 up-regulation: Involvement of Ca{sup 2+} influx

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Dong-Oh [Department of Biology Education, Daegu University, Gyungsan, Gyeongbuk 712–714 (Korea, Republic of); Kang, Chang-Hee; Kang, Sang-Hyuck [Department of Marine Life Sciences, Jeju National University, Jeju 690–756 (Korea, Republic of); Choi, Yung-Hyun [Department of Biochemistry, College of Oriental Medicine, Dongeui University, Busan 614–054 (Korea, Republic of); Hyun, Jin-Won; Chang, Weon-Young; Kang, Hee-Kyoung; Koh, Young-Sang; Maeng, Young-Hee; Kim, Young-Ree [School of Medicine, Jeju National University, Jeju-si 690–756 (Korea, Republic of); Kim, Gi-Young, E-mail: immunkim@jejunu.ac.kr [Department of Marine Life Sciences, Jeju National University, Jeju 690–756 (Korea, Republic of)

    2012-02-15

    Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various malignant cells, several cancers including human hepatocellular carcinoma (HCC) exhibit potent resistance to TRAIL-induced cell death. The aim of this study is to evaluate the anti-cancer potential of capsaicin in TRAIL-induced cancer cell death. As indicated by assays that measure phosphatidylserine exposure, mitochondrial activity and activation of caspases, capsaicin potentiated TRAIL-resistant cells to lead to cell death. In addition, we found that capsaicin induces the cell surface expression of TRAIL receptor DR5, but not DR4 through the activation Sp1 on its promoter region. Furthermore, we investigated that capsaicin-induced DR5 expression and apoptosis are inhibited by calcium chelator or inhibitors for calmodulin-dependent protein kinase. Taken together, our data suggest that capsaicin sensitizes TRAIL-mediated HCC cell apoptosis by DR5 up-regulation via calcium influx-dependent Sp1 activation. Highlights: ► Capsaicin sensitizes TRAIL-induced apoptosis through activation of caspases. ► Capsaicin induces expression of DR5 through Sp1 activation. ► Capsaicin activates calcium signaling pathway.

  4. A STIM1-dependent 'trafficking trap' mechanism regulates Orai1 plasma membrane residence and Ca²⁺ influx levels.

    Science.gov (United States)

    Hodeify, Rawad; Selvaraj, Senthil; Wen, Jennifer; Arredouani, Abdelilah; Hubrack, Satanay; Dib, Maya; Al-Thani, Sara N; McGraw, Timothy; Machaca, Khaled

    2015-08-15

    The key proteins mediating store-operated Ca(2+) entry (SOCE) are the endoplasmic reticulum (ER) Ca(2+) sensor STIM1 and the plasma membrane Ca(2+)-selective channel Orai1. Here, we quantitatively dissect Orai1 trafficking dynamics and show that Orai1 recycles rapidly at the plasma membrane (Kex≃0.1 min(-1)), with ∼40% of the total Orai1 pool localizing to the plasma membrane at steady state. A subset of intracellular Orai1 localizes to a sub-plasmalemal compartment. Store depletion is coupled to Orai1 plasma membrane enrichment in a STIM1-dependent fashion. This is due to trapping of Orai1 into cortical ER STIM1 clusters, leading to its removal from the recycling pool and enrichment at the plasma membrane. Interestingly, upon high STIM1 expression, Orai1 is trapped into STIM1 clusters intracellularly, thus preventing its plasma membrane enrichment following store depletion. Consistent with this, STIM1 knockdown prevents trapping of excess Orai1 into limiting STIM1 clusters in the cortical ER. SOCE-dependent Ca(2+) influx shows a similar biphasic dependence on the Orai1:STIM1 ratio. Therefore, a STIM1-dependent Orai1 'trafficking trap' mechanism controls Orai1 plasma membrane enrichment and SOCE levels, thus modulating the SOCE 'bandwidth' for downstream signaling. PMID:26116575

  5. Yeast Ca(2+)-signal transduction inhibitors isolated from Dominican amber prevent the degranulation of RBL-2H3 cells through the inhibition of Ca(2+)-influx.

    Science.gov (United States)

    Abe, Tomomi; Kobayashi, Miki; Okawa, Yusuke; Inui, Tomoki; Yoshida, Jun; Higashio, Hironori; Shinden, Hisao; Uesugi, Shota; Koshino, Hiroyuki; Kimura, Ken-Ichi

    2016-09-01

    A new norlabdane compound, named kujigamberol has previously been isolated from Kuji amber (but not from Baltic amber) by activity guided fractionation. However, there has been no study of biological compounds in Dominican amber. Biological activities were examined using the hypersensitive mutant yeast (zds1Δ erg3Δ pdr1Δ pdr3Δ) with respect to Ca(2+)-signal transduction, enzymes and rat basophilic leukemia (RBL)-2H3 cells. The structures were elucidated on the basis of spectral analysis including high resolution (HR)-EI-MS, 1D NMR and 2D NMR. Three diterpenoid compounds, 5(10)-halimen-15-oic acid (1), 3-cleroden-15-oic acid (2) and 8-labden-15-oic acid (3), which are different from the bioactive compounds in Kuji and Baltic ambers, were isolated from Dominican amber. They inhibited both calcineurin (CN) (IC50=40.0, 21.2 and 34.2μM) and glycogen synthase kinase-3β (GSK-3β) (IC50=48.9, 43.8 and 41.1μM) which are involved in the growth restored activity against the mutant yeast. The most abundant compound 2 showed inhibitory activity against both degranulation and Ca(2+)-influx in RBL-2H3 cells. The compounds having the growth restoring activity against the mutant yeast have potential as anti-allergic compounds. PMID:27491756

  6. Mechanics of Systems of Affine Bodies. Geometric Foundations and Applications in Dynamics of Structured Media

    CERN Document Server

    S\\lawianowski, J J; Martens, A; Go\\lubowska, B; zko, E E Ro\\

    2010-01-01

    In the present paper we investigate the mechanics of systems of affinely-rigid bodies, i.e., bodies rigid in the sense of affine geometry. Certain physical applications are possible in modelling of molecular crystals, granular media, and other physical objects. Particularly interesting are dynamical models invariant under the group underlying geometry of degrees of freedom. In contrary to the single body case there exist nontrivial potentials invariant under this group (left and right acting). The concept of relative (mutual) deformation tensors of pairs of affine bodies is discussed. Scalar invariants built of such tensors are constructed. There is an essential novelty in comparison to deformation scalars of single affine bodies, i.e., there exist affinely-invariant scalars of mutual deformations. Hence, the hierarchy of interaction models according to their invariance group, from Euclidean to affine ones, can be considered.

  7. Purification of proteins specifically binding human endogenous retrovirus K long terminal repeat by affinity elution chromatography.

    Science.gov (United States)

    Trubetskoy, D O; Zavalova, L L; Akopov, S B; Nikolaev, L G

    2002-11-01

    A novel affinity elution procedure for purification of DNA-binding proteins was developed and employed to purify to near homogeneity the proteins recognizing a 21 base pair sequence within the long terminal repeat of human endogenous retroviruses K. The approach involves loading the initial protein mixture on a heparin-agarose column and elution of protein(s) of interest with a solution of double-stranded oligonucleotide containing binding sites of the protein(s). The affinity elution has several advantages over conventional DNA-affinity chromatography: (i) it is easier and faster, permitting to isolate proteins in a 1 day-one stage procedure; (ii) yield of a target protein is severalfold higher than that in DNA-affinity chromatography; (iii) it is not necessary to prepare a special affinity support for each factor to be isolated. Theaffinity elution could be a useful alternative to conventional DNA-affinity chromatography.

  8. The classical origin of quantum affine algebra in squashed sigma models

    OpenAIRE

    Kawaguchi, Io; Matsumoto, Takuya; Yoshida, Kentaroh

    2012-01-01

    We consider a quantum affine algebra realized in two-dimensional non-linear sigma models with target space three-dimensional squashed sphere. Its affine generators are explicitly constructed and the Poisson brackets are computed. The defining relations of quantum affine algebra in the sense of the Drinfeld first realization are satisfied at classical level. The relation to the Drinfeld second realization is also discussed including higher conserved charges. Finally we comment on a semiclassic...

  9. APPLICATION OF IMMUNOGLOBULIN-BINDING PROTEINS A, G, L IN THE AFFINITY CHROMATOGRAPHY

    OpenAIRE

    Sviatenko, О.; Gorbatiuk, O.; Vasylchenko, О.

    2014-01-01

    Proteins A, G and L are native or recombinant proteins of microbial origin that bind to mammalian immunoglobulins. Preferably recombinant variants of proteins A, G, L are used in biotechnology for affinity sorbents production. Сomparative characteristics of proteins A, G, L and affinity sorbents on the basis of them, advantages and disadvantages of these proteins application as ligands in the affinity chromatography are done. Analysis of proteins A, G, L properties is presented. Binding speci...

  10. Endomorphin analogues with balanced affinity for both μ- and δ-opioid receptors

    Institute of Scientific and Technical Information of China (English)

    Liang Zhang; Lei Chang; Lei Lei Yu; Jin Chun Liu; Jia Jia Chen; Xiao Wen Li; Lawrence H. Lazarus; Ting You Li

    2011-01-01

    Analogues of endomorphin and tripeptides modified at positions 4 and 3, respectively, with various phenylalanine analogues were synthesized and their affinities for opioid receptors were evaluated. Most of the peptides exhibited potent μ-receptor affinity and selectivity, among them, compound 7 (Dmt-Pro-Tmp-Tmp-NH2) exhibited potent affinity for both μ- and δ-receptors (Kiμ = 0.47 nmol/L, Kiδ = 1.63 nmol/L).

  11. On the defining relations of the affine Lie superalgebras and their quantized universal enveloping superalgebras

    CERN Document Server

    Yamane, H

    1996-01-01

    In this paper, we give defining relations of the affine Lie superalgebras an and defining relations of a super-version of the Drinfeld[D]-Jimbo[J] affine quantized universal enveloping algebras. As a result, we can exactly define the affine quantized universal enveloping superalgebras with generators and relations. Moreover we give a Drinfeld's realizations of U_h({\\hat {sl}}(m|n)^{(1)}).

  12. Synthesis and receptor binding affinity of new selective GluR5 ligands

    DEFF Research Database (Denmark)

    Bunch, L; Johansen, T H; Bräuner-Osborne, Hans;

    2001-01-01

    Two hybrid analogues of the kainic acid receptor agonists, 2-amino-3-(5-tert-butyl-3-hydroxy-4-isoxazolyl)propionic acid (ATPA) and (2S,4R)-4-methylglutamic acid ((2S,4R)-4-Me-Glu), were designed, synthesized, and characterized in radioligand binding assays using cloned ionotropic and metabotropi.......0 and 2.0 microM. respectively. Their affinities in the [3H]AMPA binding assay on native cortical receptors were shown to correlate with their GluR2 affinity rather than their GluR5 affinity. No affinity for GluR6 was detected (IC50 > 100 microM)....

  13. Influences of hydrocarbon linkers on the receptor binding affinities of gonadotropin-releasing hormone peptides

    OpenAIRE

    Guo, Haixun; Hathaway, Helen; Royce, Melanie E.; Prossnitz, Eric R.; Miao, Yubin

    2013-01-01

    Three new DOTA-conjugated GnRH peptides with various hydrocarbon linkers were synthesized to evaluate the influences of the linkers on their receptor binding affinities. The hydrocarbon linker displayed a profound impact on the receptor binding affinities of DOTA-conjugated GnRH peptides. The Aun linker was better than Gaba, Ahx and Aoc linkers in retaining strong receptor binding affinity of the GnRH peptide. DOTA-Aun-(D-Lys6-GnRH) displayed 22.8 nM GnRH receptor binding affinity. 111In-DOTA...

  14. Applications of on-line weak affinity interactions in free solution capillary electrophoresis

    DEFF Research Database (Denmark)

    Heegaard, Niels H H; Nissen, Mogens H; Chen, David D Y

    2002-01-01

    The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary electropho......The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary...

  15. Affinity functions: recognizing essential parameters in fuzzy connectedness based image segmentation

    Science.gov (United States)

    Ciesielski, Krzysztof C.; Udupa, Jayaram K.

    2009-02-01

    Fuzzy connectedness (FC) constitutes an important class of image segmentation schemas. Although affinity functions represent the core aspect (main variability parameter) of FC algorithms, they have not been studied systematically in the literature. In this paper, we present a thorough study to fill this gap. Our analysis is based on the notion of equivalent affinities: if any two equivalent affinities are used in the same FC schema to produce two versions of the algorithm, then these algorithms are equivalent in the sense that they lead to identical segmentations. We give a complete characterization of the affinity equivalence and show that many natural definitions of affinity functions and their parameters used in the literature are redundant in the sense that different definitions and values of such parameters lead to equivalent affinities. We also show that two main affinity types - homogeneity based and object feature based - are equivalent, respectively, to the difference quotient of the intensity function and Rosenfeld's degree of connectivity. In addition, we demonstrate that any segmentation obtained via relative fuzzy connectedness (RFC) algorithm can be viewed as segmentation obtained via absolute fuzzy connectedness (AFC) algorithm with an automatic and adaptive threshold detection. We finish with an analysis of possible ways of combining different component affinities that result in non equivalent affinities.

  16. Congruence of genomic and ethnolinguistic affinities among five tribal populations of Madhya Pradesh (India)

    Indian Academy of Sciences (India)

    Namita Mukherjee; Mitashree Mitra; Madan Chakraborty; Partha P. Majumder

    2000-08-01

    The central Indian state of Madhya Pradesh is home to a large number of tribal populations of diverse linguistic and ethnic backgrounds. With a view to examining how well genomic affinities among tribal populations of this state correspond with their ethnic and linguistic affinities, we analysed DNA samples of individuals drawn from five tribes with diverse, but reasonably well-documented, ethnohistorical and linguistic backgrounds. Each DNA sample was scored at 16 biallelic DNA marker loci. On the basis of these data, genomic affinities among these populations were estimated. We have found an extremely good correspondence between the genomic and ethnolinguistic affinities.

  17. Hemoglobin oxygen affinity in patients with cystic fibrosis.

    Directory of Open Access Journals (Sweden)

    Dieter Böning

    Full Text Available In patients with cystic fibrosis lung damages cause arterial hypoxia. As a typical compensatory reaction one might expect changes in oxygen affinity of hemoglobin. Therefore position (standard half saturation pressure P50st and slope (Hill's n of the O2 dissociation curve as well as the Bohr coefficients (BC for CO2 and lactic acid were determined in blood of 14 adult patients (8 males, 6 females and 14 healthy controls (6 males, 8 females. While Hill's n amounted to approximately 2.6 in all subjects, P50st was slightly increased by 1 mmHg in both patient groups (controls male 26.7 ± 0.2, controls female 27.0 ± 0.1, patients male 27.7 ± 0.5, patients female 28.0 ± 0.3 mmHg; mean and standard error, overall p<0.01. Main cause was a rise of 1-2 µmol/g hemoglobin in erythrocytic 2,3-biphosphoglycerate concentration. One patient only, clearly identified as an outlier and with the mutation G551D, showed a reduction of both P50st (24.5 mmHg and [2,3-biphosphoglycerate] (9.8 µmol/g hemoglobin. There were no differences in BCCO2, but small sex differences in the BC for lactic acid in the controls which were not detectable in the patients. Causes for the right shift of the O2 dissociation curve might be hypoxic stimulation of erythrocytic glycolysis and an increased red cell turnover both causing increased [2,3-biphosphoglycerate]. However, for situations with additional hypercapnia as observed in exercising patients a left shift seems to be a more favourable adaptation in cystic fibrosis. Additionally when in vivo PO2 values were corrected to the standard conditions they mostly lay left of the in vitro O2 dissociation curve in both patients and controls. This hints to unknown fugitive factors influencing oxygen affinity.

  18. High Affinity Binding of Indium and Ruthenium Ions by Gastrins.

    Directory of Open Access Journals (Sweden)

    Graham S Baldwin

    Full Text Available The peptide hormone gastrin binds two ferric ions with high affinity, and iron binding is essential for the biological activity of non-amidated forms of the hormone. Since gastrins act as growth factors in gastrointestinal cancers, and as peptides labelled with Ga and In isotopes are increasingly used for cancer diagnosis, the ability of gastrins to bind other metal ions was investigated systematically by absorption spectroscopy. The coordination structures of the complexes were characterized by extended X-ray absorption fine structure (EXAFS spectroscopy. Changes in the absorption of gastrin in the presence of increasing concentrations of Ga3+ were fitted by a 2 site model with dissociation constants (Kd of 3.3 x 10-7 and 1.1 x 10-6 M. Although the absorption of gastrin did not change upon the addition of In3+ ions, the changes in absorbance on Fe3+ ion binding in the presence of indium ions were fitted by a 2 site model with Kd values for In3+ of 6.5 x 10-15 and 1.7 x 10-7 M. Similar results were obtained with Ru3+ ions, although the Kd values for Ru3+ of 2.6 x 10-13 and 1.2 x 10-5 M were slightly larger than observed for In3+. The structures determined by EXAFS all had metal:gastrin stoichiometries of 2:1 but, while the metal ions in the Fe, Ga and In complexes were bridged by a carboxylate and an oxygen with a metal-metal separation of 3.0-3.3 Å, the Ru complex clearly demonstrated a short range Ru-Ru separation, which was significantly shorter, at 2.4 Å, indicative of a metal-metal bond. We conclude that gastrin selectively binds two In3+ or Ru3+ ions, and that the affinity of the first site for In3+ or Ru3+ ions is higher than for ferric ions. Some of the metal ion-gastrin complexes may be useful for cancer diagnosis and therapy.

  19. Genetic affinities between endogamous and inbreeding populations of Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Borkar Minal

    2007-04-01

    Full Text Available Abstract Background India has experienced several waves of migration since the Middle Paleolithic. It is believed that the initial demic movement into India was from Africa along the southern coastal route, approximately 60,000–85,000 years before present (ybp. It has also been reported that there were two other major colonization which included eastward diffusion of Neolithic farmers (Elamo Dravidians from Middle East sometime between 10,000 and 7,000 ybp and a southern dispersal of Indo Europeans from Central Asia 3,000 ybp. Mongol entry during the thirteenth century A.D. as well as some possible minor incursions from South China 50,000 to 60,000 ybp may have also contributed to cultural, linguistic and genetic diversity in India. Therefore, the genetic affinity and relationship of Indians with other world populations and also within India are often contested. In the present study, we have attempted to offer a fresh and immaculate interpretation on the genetic relationships of different North Indian populations with other Indian and world populations. Results We have first genotyped 20 tetra-nucleotide STR markers among 1800 north Indian samples of nine endogamous populations belonging to three different socio-cultural strata. Genetic distances (Nei's DA and Reynold's Fst were calculated among the nine studied populations, Caucasians and East Asians. This analysis was based upon the allelic profile of 20 STR markers to assess the genetic similarity and differences of the north Indian populations. North Indians showed a stronger genetic relationship with the Europeans (DA 0.0341 and Fst 0.0119 as compared to the Asians (DA 0.1694 and Fst – 0.0718. The upper caste Brahmins and Muslims were closest to Caucasians while middle caste populations were closer to Asians. Finally, three phylogenetic assessments based on two different NJ and ML phylogenetic methods and PC plot analysis were carried out using the same panel of 20 STR markers and 20

  20. Short-term desensitization of muscarinic cholinergic receptors in mouse neuroblastoma cells: selective loss of agonist low-affinity and pirenzepine high-affinity binding sites

    International Nuclear Information System (INIS)

    The effects of brief incubation with carbamylcholine on subsequent binding of [3H]N-methylscopolamine were investigated in mouse neuroblastoma cells (clone N1E-115). This treatment demonstrated that the muscarinic receptors in this neuronal clone can be divided into two types; one which is readily susceptible to regulation by receptor agonists, whereas the other is resistant in this regard. In control cells, both pirenzepine and carbamylcholine interacted with high- and low-affinity subsets of muscarinic receptors. Computer-assisted analysis of the competition between pirenzepine and carbamylcholine with [3H]N-methylscopolamine showed that the receptor sites remaining upon desensitization are composed mainly of pirenzepine low-affinity and agonist high-affinity binding sites. Furthermore, there was an excellent correlation between the ability of various muscarinic receptor agonists to induce a decrease in consequent [3H]N-methylscopolamine binding and their efficacy in stimulating cyclic GMP synthesis in these cells. Thus, only the agonists that are known to recognize the receptor's low-affinity conformation in order to elicit increases in cyclic GMP levels were capable of diminishing ligand binding. Taken together, our present results suggest that the receptor population that is sensitive to regulation by agonists includes both the pirenzepine high-affinity and the agonist low-affinity receptor binding states. In addition, the sensitivity of these receptor subsets to rapid regulation by agonists further implicates their involvement in desensitization of muscarinic receptor-mediated cyclic GMP formation

  1. Preproglucagon neurons in the hindbrain have IL-6 receptor-α and show Ca2+ influx in response to IL-6.

    Science.gov (United States)

    Anesten, Fredrik; Holt, Marie K; Schéle, Erik; Pálsdóttir, Vilborg; Reimann, Frank; Gribble, Fiona M; Safari, Cecilia; Skibicka, Karolina P; Trapp, Stefan; Jansson, John-Olov

    2016-07-01

    Neuronal circuits in the hypothalamus and hindbrain are of importance for control of food intake, energy expenditure, and fat mass. We have recently shown that treatment with exendin-4 (Ex-4), an analog of the proglucagon-derived molecule glucagon-like peptide 1 (GLP-1), markedly increases mRNA expression of the cytokine interleukin-6 (IL-6) in the hypothalamus and hindbrain and that this increase partly mediates the suppression of food intake and body weight by Ex-4. Endogenous GLP-1 in the central nervous system (CNS) is produced by preproglucagon (PPG) neurons of the nucleus of the solitary tract (NTS) in the hindbrain. These neurons project to various parts of the brain, including the hypothalamus. Outside the brain, IL-6 stimulates GLP-1 secretion from the gut and pancreas. In this study, we aim to investigate whether IL-6 can affect GLP-1-producing PPG neurons in the nucleus of the solitary tract (NTS) in mouse hindbrain via the ligand binding part of the IL-6 receptor, IL-6 receptor-α (IL-6Rα). Using immunohistochemistry, we found that IL-6Rα was localized on PPG neurons of the NTS. Recordings of these neurons in GCaMP3/GLP-1 reporter mice showed that IL-6 enhances cytosolic Ca(2+) concentration in neurons capable of expressing PPG. We also show that the Ca(2+) increase originates from the extracellular space. Furthermore, we found that IL-6Rα was localized on cells in the caudal hindbrain expressing immunoreactive NeuN (a neuronal marker) or CNP:ase (an oligodendrocyte marker). In summary, IL-6Rα is present on PPG neurons in the NTS, and IL-6 can stimulate these cells by increasing influx of Ca(2+) to the cytosol from the extracellular space. PMID:27097661

  2. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2, leading to cell depolarization and calcium influx.

    Science.gov (United States)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Wewer Albrechtsen, Nicolai Jacob; Hartmann, Bolette; Holst, Jens Juul

    2015-06-15

    Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans, but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide, which causes hyperpolarization, eliminated the response. Luminal inhibition of the sodium-glucose cotransporter 1 (SGLT1) (by phloridzin) eliminated glucose-stimulated release as well as secretion stimulated by luminal methyl-α-D-glucopyranoside (20% wt/vol), a metabolically inactive SGLT1 substrate, suggesting that glucose stimulates secretion by initial uptake by this transporter. However, secretion was also sensitive to GLUT2 inhibition (by phloretin) and blockage of oxidative phosphorylation (2-4-dinitrophenol). Direct KATP channel closure by sulfonylureas stimulated secretion. Therefore, glucose stimulates NT secretion by uptake through SGLT1 and GLUT2, both causing depolarization either as a consequence of sodium-coupled uptake (SGLT1) or by closure of KATP channels (GLUT2 and SGLT1) secondary to the ATP-generating metabolism of glucose.

  3. Microdomain Ca2+ Activation during Exocytosis in Paramecium Cells. Superposition of Local Subplasmalemmal Calcium Store Activation by Local Ca2+ Influx

    Science.gov (United States)

    Erxleben, Christian; Klauke, Norbert; Flötenmeyer, Matthias; Blanchard, Marie-Pierre; Braun, Claudia; Plattner, Helmut

    1997-01-01

    In Paramecium tetraurelia, polyamine-triggered exocytosis is accompanied by the activation of Ca2+-activated currents across the cell membrane (Erxleben, C., and H. Plattner. 1994. J. Cell Biol. 127:935– 945). We now show by voltage clamp and extracellular recordings that the product of current × time (As) closely parallels the number of exocytotic events. We suggest that Ca2+ mobilization from subplasmalemmal storage compartments, covering almost the entire cell surface, is a key event. In fact, after local stimulation, Ca2+ imaging with high time resolution reveals rapid, transient, local signals even when extracellular Ca2+ is quenched to or below resting intracellular Ca2+ concentration ([Ca2+]e ⩽ [Ca2+]i). Under these conditions, quenched-flow/freeze-fracture analysis shows that membrane fusion is only partially inhibited. Increasing [Ca2+]e alone, i.e., without secretagogue, causes rapid, strong cortical increase of [Ca2+]i but no exocytosis. In various cells, the ratio of maximal vs. minimal currents registered during maximal stimulation or single exocytotic events, respectively, correlate nicely with the number of Ca stores available. Since no quantal current steps could be observed, this is again compatible with the combined occurrence of Ca2+ mobilization from stores (providing close to threshold Ca2+ levels) and Ca2+ influx from the medium (which per se does not cause exocytosis). This implies that only the combination of Ca2+ flushes, primarily from internal and secondarily from external sources, can produce a signal triggering rapid, local exocytotic responses, as requested for Paramecium defense. PMID:9024690

  4. NLRP3 inflammasome signaling is activated by low-level lysosome disruption but inhibited by extensive lysosome disruption: roles for K+ efflux and Ca2+ influx.

    Science.gov (United States)

    Katsnelson, Michael A; Lozada-Soto, Kristen M; Russo, Hana M; Miller, Barbara A; Dubyak, George R

    2016-07-01

    Nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3 (NLRP3) is a cytosolic protein that nucleates assembly of inflammasome signaling platforms, which facilitate caspase-1-mediated IL-1β release and other inflammatory responses in myeloid leukocytes. NLRP3 inflammasomes are assembled in response to multiple pathogen- or environmental stress-induced changes in basic cell physiology, including the destabilization of lysosome integrity and activation of K(+)-permeable channels/transporters in the plasma membrane (PM). However, the quantitative relationships between lysosome membrane permeabilization (LMP), induction of increased PM K(+) permeability, and activation of NLRP3 signaling are incompletely characterized. We used Leu-Leu-O-methyl ester (LLME), a soluble lysosomotropic agent, to quantitatively track the kinetics and extent of LMP in relation to NLRP3 inflammasome signaling responses (ASC oligomerization, caspase-1 activation, IL-1β release) and PM cation fluxes in murine bone marrow-derived dendritic cells (BMDCs). Treatment of BMDCs with submillimolar (≤1 mM) LLME induced slower and partial increases in LMP that correlated with robust NLRP3 inflammasome activation and K(+) efflux. In contrast, supramillimolar (≥2 mM) LLME elicited extremely rapid and complete collapse of lysosome integrity that was correlated with suppression of inflammasome signaling. Supramillimolar LLME also induced dominant negative effects on inflammasome activation by the canonical NLRP3 agonist nigericin; this inhibition correlated with an increase in NLRP3 ubiquitination. LMP elicited rapid BMDC death by both inflammasome-dependent pyroptosis and inflammasome-independent necrosis. LMP also triggered Ca(2+) influx, which attenuated LLME-stimulated NLRP3 inflammasome signaling but potentiated LLME-induced necrosis. Taken together, these studies reveal a previously unappreciated signaling network that defines the coupling between LMP, changes

  5. Antagonism of Ca2+ influx via L-type Ca2+ channels mediates the vasorelaxant effect of Catharanthus roseus-derived vindorosine in rat renal artery.

    Science.gov (United States)

    Wu, Xiao-Lin; Cheang, Wai San; Zhang, Dong-Mei; Li, Yong; Lau, Chi-Wai; Wang, Guo-Cai; Huang, Yu; Ye, Wen-Cai

    2014-12-01

    Catharanthus roseus is a traditional herbal medicine used in Asian and African countries for the treatment of various diseases including hypertension. The present study examined possible cellular mechanisms for the relaxation of rat renal arteries induced by vindorosine extracted from C. roseus. Intrarenal arteries were isolated from 200-300 g male Sprague-Dawley rats and treated with different pharmacological blockers and inhibitors for the measurement of vascular reactivity on a Multi Myograph System. Fluorescence imaging by laser scanning confocal microscopy was utilized to determine the intracellular Ca(2+) level in the vascular smooth muscles of the renal arteries. Vindorosine in micromolar concentrations relaxes renal arteries precontracted by KCl, phenylephrine, 11-dideoxy-9α,11α-epoxymethanoprostaglandin F2α, and serotonin. Vindorosine-induced relaxations were unaffected by endothelium denudation or by treatment with the nitric oxide synthase inhibitor N (G)-nitro-L-arginine methyl ester hydrochloride, the guanylyl cyclase inhibitor 1H-[1, 2, 4]oxadiazolo[4,3-a]quinoxalin-1-one, the cyclooxygenase inhibitor indomethacin, or K(+) channel blockers such as tetraethylammonium ions, glibenclamide, and BaCl2. Vindorosine-induced relaxations were attenuated in the presence of 0.1 µM nifedipine (an L-type Ca(2+) channel blocker). Vindorosine also concentration-dependently suppressed contractions induced by CaCl2 (0.01-5 mM) in Ca-free 60 mM KCl solution. Furthermore, fluorescence imaging using fluo-4 demonstrated that 30 min incubation with 100 µM vindorosine reduced the 60 mM KCl-stimulated Ca(2+) influx in the smooth muscles of rat renal arteries. The present study is probably the first report of blood vessel relaxation by vindorosine and the possible underlying mechanisms involving the inhibition of Ca(2+) entry via L-type Ca(2+) channels in vascular smooth muscles. PMID:25340466

  6. A Catalog of Self-Affine Hierarchical Entropy Functions

    Directory of Open Access Journals (Sweden)

    John Kieffer

    2011-11-01

    Full Text Available For fixed k ≥ 2 and fixed data alphabet of cardinality m, the hierarchical type class of a data string of length n = kj for some j ≥ 1 is formed by permuting the string in all possible ways under permutations arising from the isomorphisms of the unique finite rooted tree of depth j which has n leaves and k children for each non-leaf vertex. Suppose the data strings in a hierarchical type class are losslessly encoded via binary codewords of minimal length. A hierarchical entropy function is a function on the set of m-dimensional probability distributions which describes the asymptotic compression rate performance of this lossless encoding scheme as the data length n is allowed to grow without bound. We determine infinitely many hierarchical entropy functions which are each self-affine. For each such function, an explicit iterated function system is found such that the graph of the function is the attractor of the system.

  7. Speech Enhancement Using Kernel and Normalized Kernel Affine Projection Algorithm

    Directory of Open Access Journals (Sweden)

    Bolimera Ravi

    2013-08-01

    Full Text Available The goal of this paper is to investigate the speech signal enhancement using Kernel Affine ProjectionAlgorithm (KAPA and Normalized KAPA. The removal of background noise is very important in manyapplications like speech recognition, telephone conversations, hearing aids, forensic, etc. Kernel adaptivefilters shown good performance for removal of noise. If the evaluation of background noise is more slowlythan the speech, i.e., noise signal is more stationary than the speech, we can easily estimate the noiseduring the pauses in speech. Otherwise it is more difficult to estimate the noise which results indegradation of speech. In order to improve the quality and intelligibility of speech, unlike time andfrequency domains, we can process the signal in new domain like Reproducing Kernel Hilbert Space(RKHS for high dimensional to yield more powerful nonlinear extensions. For experiments, we have usedthe database of noisy speech corpus (NOIZEUS. From the results, we observed the removal noise in RKHShas great performance in signal to noise ratio values in comparison with conventional adaptive filters.

  8. An affinity-directed protein missile system for targeted proteolysis

    Science.gov (United States)

    Fulcher, Luke J.; Macartney, Thomas; Bozatzi, Polyxeni; Hornberger, Annika; Rojas-Fernandez, Alejandro

    2016-01-01

    The von Hippel–Lindau (VHL) protein serves to recruit the hypoxia-inducible factor alpha (HIF1α) protein under normoxia to the CUL2 E3 ubiquitin ligase for its ubiquitylation and degradation through the proteasome. In this report, we modify VHL to engineer an affinity-directed protein missile (AdPROM) system to direct specific endogenous target proteins for proteolysis in mammalian cells. The proteolytic AdPROM construct harbours a cameloid anti-green fluorescence protein (aGFP) nanobody that is fused to VHL for either constitutive or tetracycline-inducible expression. For target proteins, we exploit CRISPR/Cas9 to rapidly generate human kidney HEK293 and U2OS osteosarcoma homozygous knock-in cells harbouring GFP tags at the VPS34 (vacuolar protein sorting 34) and protein associated with SMAD1 (PAWS1, aka FAM83G) loci, respectively. Using these cells, we demonstrate that the expression of the VHL-aGFP AdPROM system results in near-complete degradation of the endogenous GFP-VPS34 and PAWS1-GFP proteins through the proteasome. Additionally, we show that Tet-inducible destruction of GFP-VPS34 results in the degradation of its associated partner, UVRAG, and reduction in levels of cellular phosphatidylinositol 3-phosphate. PMID:27784791

  9. Displacement affinity chromatography of protein phosphatase one (PP1 complexes

    Directory of Open Access Journals (Sweden)

    Gourlay Robert

    2008-11-01

    Full Text Available Abstract Background Protein phosphatase one (PP1 is a ubiquitously expressed, highly conserved protein phosphatase that dephosphorylates target protein serine and threonine residues. PP1 is localized to its site of action by interacting with targeting or regulatory proteins, a majority of which contains a primary docking site referred to as the RVXF/W motif. Results We demonstrate that a peptide based on the RVXF/W motif can effectively displace PP1 bound proteins from PP1 retained on the phosphatase affinity matrix microcystin-Sepharose. Subsequent co-immunoprecipitation experiments confirmed that each identified binding protein was either a direct PP1 interactor or was in a complex that contains PP1. Our results have linked PP1 to numerous new nuclear functions and proteins, including Ki-67, Rif-1, topoisomerase IIα, several nuclear helicases, NUP153 and the TRRAP complex. Conclusion This modification of the microcystin-Sepharose technique offers an effective means of purifying novel PP1 regulatory subunits and associated proteins and provides a simple method to uncover a link between PP1 and additional cellular processes.

  10. New Insights into Viral Architecture via Affine Extended Symmetry Groups

    Directory of Open Access Journals (Sweden)

    T. Keef

    2008-01-01

    Full Text Available Since the seminal work of Caspar and Klug on the structure of the protein containers that encapsulate and hence protect the viral genome, it has been recognized that icosahedral symmetry is crucial for the structural organization of viruses. In particular, icosahedral symmetry has been invoked in order to predict the surface structures of viral capsids in terms of tessellations or tilings that schematically encode the locations of the protein subunits in the capsids. Whilst this approach is capable of predicting the relative locations of the proteins in the capsids, a prediction on the relative sizes of different virus particles in a family cannot be made. Moreover, information on the full 3D structure of viral particles, including the tertiary structures of the capsid proteins and the organization of the viral genome within the capsid are inaccessible with their approach. We develop here a mathematical framework based on affine extensions of the icosahedral group that allows us to address these issues. In particular, we show that the relative radii of viruses in the family of Polyomaviridae and the material boundaries in simple RNA viruses can be determined with our approach. The results complement Caspar and Klug's theory of quasi-equivalence and provide details on virus structure that have not been accessible with previous methods, implying that icosahedral symmetry is more important for virus architecture than previously appreciated.

  11. Surface Plasmon Resonance for Rapid Screening of Uranyl Affine Proteins

    International Nuclear Information System (INIS)

    A sensitive immunoassay based on SPR analysis was developed to measure uranyl cation (UO22+) affinity for any protein in a free state under physiological conditions. The technique involves immobilization of a specific monoclonal antibody (mAb) raised against UO22+ and 1, 10-phenanthroline-2, 9-dicarboxylic acid (DCP) used as a probe of UO22+ captured by the mAb. Calibration curves were established for accurate determination of UO22+ concentrations with a detection limit of 7 nM. The remaining free UO22+ could be accurately quantified from the different protein-metal equilibrium and a dose-response curve established for KD determination. This generic method was applied not only to proteins such as transferrin and albumin but also to small phosphonated ligands. Its robustness allows the fast UO22+ KD determination of any kind of macromolecules and small ligands using very few amount of compounds, thus opening new prospects in the field of uranium toxicity. (authors)

  12. High-throughput analysis of protein-DNA binding affinity.

    Science.gov (United States)

    Franco-Zorrilla, José M; Solano, Roberto

    2014-01-01

    Sequence-specific protein-DNA interactions mediate most regulatory processes underlying gene expression, such as transcriptional regulation by transcription factors (TFs) or chromatin organization. Current knowledge about DNA-binding specificities of TFs is based mostly on low- to medium-throughput methodologies that are time-consuming and often fail to identify DNA motifs recognized by a TF with lower affinity but retaining biological relevance. The use of protein-binding microarrays (PBMs) offers a high-throughput alternative for the identification of protein-DNA specificities. PBM consists in an array of pseudorandomized DNA sequences that are optimized to include all the possible 10- or 11-mer DNA sequences, allowing the determination of binding specificities of most eukaryotic TFs. PBMs that can be synthesized by several manufacturing companies as single-stranded DNA are converted into double-stranded in a simple primer extension reaction. The protein of interest fused to an epitope tag is then incubated onto the PBM, and specific DNA-protein complexes are revealed in a series of immunological reactions coupled to a fluorophore. After scanning and quantifying PBMs, specific DNA motifs recognized by the protein are identified with ready-to-use scripts, generating comprehensive but accessible information about the DNA-binding specificity of the protein. This chapter describes detailed procedures for preparation of double-stranded PBMs, incubation with recombinant protein, and detection of protein-DNA complexes. Finally, we outline some cues for evaluating the biological role of DNA motifs obtained in vitro. PMID:24057393

  13. Affinity for Quantitative Tools: Undergraduate Marketing Students Moving beyond Quantitative Anxiety

    Science.gov (United States)

    Tarasi, Crina O.; Wilson, J. Holton; Puri, Cheenu; Divine, Richard L.

    2013-01-01

    Marketing students are known as less likely to have an affinity for the quantitative aspects of the marketing discipline. In this article, we study the reasons why this might be true and develop a parsimonious 20-item scale for measuring quantitative affinity in undergraduate marketing students. The scale was administered to a sample of business…

  14. Improved methodology for the affinity isolation of human protein complexes expressed at near endogenous levels

    DEFF Research Database (Denmark)

    Domanski, Michal; Molloy, Kelly; Jiang, Hua;

    2012-01-01

    An efficient and reliable procedure for the capture of affinity-tagged proteins and associated complexes from human cell lines is reported. Through multiple optimizations, high yield and low background affinity-purifications are achieved from modest quantities of human cells expressing endogenous...

  15. Interest Rates with Long Memory: A Generalized Affine Term-Structure Model

    DEFF Research Database (Denmark)

    Osterrieder, Daniela

    We propose a model for the term structure of interest rates that is a generalization of the discrete-time, Gaussian, affine yield-curve model. Compared to standard affine models, our model allows for general linear dynamics in the vector of state variables. In an application to real yields of U...

  16. Relative binding affinity of steroids for the corticosterone receptor system in rat hippocampus

    NARCIS (Netherlands)

    De Kloet, E R; Veldhuis, H D; Wagenaars, J L; Bergink, E W

    1984-01-01

    In cytosol of the hippocampus corticosterone displays highest affinity for the sites that remain available for binding in the presence of excess RU 26988, which is shown to be a "pure" glucocorticoid. A rather high affinity (greater than or equal to 25%) was found for 11 beta-hydroxyprogesterone, 21

  17. POLYNOMIAL REPRESENTATIONS OF THE AFFINE NAPPI-WITTEN LIE ALGEBRA (H)4

    Institute of Scientific and Technical Information of China (English)

    Chen Xue; Huang Zhili

    2012-01-01

    In this paper,the representation theory for the affine Lie algebra (H)4 associated to the Nappi-Witten Lie algebra H4 is studied.Polynomial representations of the affine Nappi-Witten Lie algebra (H)4 are given.

  18. The application of magnetic force differentiation for the measurement of the affinity of peptide libraries

    International Nuclear Information System (INIS)

    A new method has been developed for measuring the binding affinity of phage displayed peptides and a target protein using magnetic particles. The specific interaction between the phage displayed peptides and the target protein was subject to a force generated by the magnetic particle. The binding affinity was obtained by analyzing the force-bond lifetime

  19. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas;

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...

  20. pH dependence of copper geometry, reduction potential, and nitrite affinity in nitrite reductase.

    NARCIS (Netherlands)

    Jacobson, F.; Pistorius, A.M.A.; Farkas, D.; Grip, W.J. de; Hansson, O.; Sjolin, L.; Neutze, R.

    2007-01-01

    Many properties of copper-containing nitrite reductase are pH-dependent, such as gene expression, enzyme activity, and substrate affinity. Here we use x-ray diffraction to investigate the structural basis for the pH dependence of activity and nitrite affinity by examining the type 2 copper site and