WorldWideScience

Sample records for central channel residues

  1. Channeling the Central Dogma.

    Science.gov (United States)

    Calabrese, Ronald L

    2014-05-21

    How do neurons and networks achieve their characteristic electrical activity, regulate this activity homeostatically, and yet show population variability in expression? In this issue of Neuron, O'Leary et al. (2014) address some of these thorny questions in this theoretical analysis that starts with the Central Dogma. PMID:24853932

  2. Role of Tryptophan Residues in Gramicidin Channel Organization and Function

    OpenAIRE

    Chattopadhyay, Amitabha; RAWAT, SATINDER S.; Greathouse, Denise V.; Kelkar, Devaki A.; Koeppe, Roger E.

    2008-01-01

    The linear peptide gramicidin forms prototypical ion channels specific for monovalent cations and has been used extensively to study the organization, dynamics, and function of membrane-spanning channels. The tryptophan residues in gramicidin channels are crucial for maintaining the structure and function of the channel. We explored the structural basis for the reduction in channel conductance in the case of single-tryptophan analogs of gramicidin with three Trp → hydrophobic substitutions us...

  3. Pesticide residues in the soil of the Central Jordan Valley

    International Nuclear Information System (INIS)

    Soil samples were taken from three zones in the Central Jordan Valley to evaluate the range of contamination with pesticides. Several pesticides belonging to different groups, particularly chlorinated hydrocarbon insecticides such as the DDT family and cyclodienes, were detected. In zone I, most of the chlorinated hydrocarbon insecticides occurred in open fields cultivated with tomatoes at a depth of 30-60 cm, at 0-15 and 15-30 cm in zone II, and at 0-15 and 30-60 cm in zone III. When considering pesticide residues under plastic house conditions cultivated with tomatoes, most of the chlorinated hydrocarbon insecticide residues were detected at a depth of 0-15 and 15-30 cm in zone I, at 0-15, 15-30 and 30-60 cm in zone II, and at 0-15 and 15-30 cm in zone III of the Central Jordan Valley. (author). 13 refs, 3 tabs

  4. Present-day dynamic and residual topography in central Anatolia

    Science.gov (United States)

    Uluocak, Ebru Şengül; Pysklywec, Russell; Göğüş, Oğuz H.

    2016-06-01

    The Central Anatolian orogenic plateau is represented by young volcanism, rapid plateau uplift, and distinctive (past and active) tectonic deformation. In this study, we consider observational data in terms of regional present-day geodynamics in the region. The residual topography of Central Anatolia was derived to define the regional isostatic conditions according to Airy isostasy and infer the potential role of "dynamic topography". Two-dimensional thermo-mechanical forward models for coupled mantle-lithosphere flow/deformation were conducted along a N-S directional profile through the region (e.g. northern/Pontides, interior, and southern/Taurides). These models were based on seismic tomography data that provide estimates about the present-day mantle thermal structure beneath the Anatolian plate. We compare the modelling results with calculated residual topography and independent data sets of geological deformation, gravity, and high surface heat flow/widespread geothermal activity. Model results suggest that there is ˜1 km of mantle flow induced dynamic topography associated with the sub-lithospheric flow driven by the seismically-inferred mantle structure. The uprising mantle may have also driven the asthenospheric source of volcanism in the north (e.g. Galatia volcanic province) and the Cappadocia volcanic province in the south while elevating the surface in the last 10 Myrs. Our dynamic topography calculations emphasize the role of vertical forcing under other orogenic plateaux underlain by relatively thin crust and low-density asthenospheric mantle.

  5. Functional expression of an arachnid sodium channel reveals residues responsible for tetrodotoxin resistance in invertebrate sodium channels.

    Science.gov (United States)

    Du, Yuzhe; Nomura, Yoshiko; Liu, Zhiqi; Huang, Zachary Y; Dong, Ke

    2009-12-01

    Tetrodotoxin (TTX) is a potent blocker of voltage-gated sodium channels, but not all sodium channels are equally sensitive to inhibition by TTX. The molecular basis of differential TTX sensitivity of mammalian sodium channels has been largely elucidated. In contrast, our knowledge about the sensitivity of invertebrate sodium channels to TTX remains poor, in part because of limited success in functional expression of these channels. In this study, we report the functional characterization in Xenopus oocytes of the first non-insect, invertebrate voltage-gated sodium channel from the varroa mite (Varroa destructor), an ecto-parasite of the honeybee. This arachnid sodium channel activates and inactivates rapidly with half-maximal activation at -18 mV and half-maximal fast inactivation at -29 mV. Interestingly, this arachnid channel showed surprising TTX resistance. TTX blocked this channel with an IC(50) of 1 microM. Subsequent site-directed mutagenesis revealed two residues, Thr-1674 and Ser-1967, in the pore-forming region of domains III and IV, respectively, which were responsible for the observed resistance to inhibition by TTX. Furthermore, sequence comparison and additional amino acid substitutions suggested that sequence polymorphisms at these two positions could be a widespread mechanism for modulating TTX sensitivity of sodium channels in diverse invertebrates. PMID:19828457

  6. Membrane Organization and Dynamics of ‘Inner Pair’ and ‘Outer Pair’ Tryptophan Residues in Gramicidin Channels

    OpenAIRE

    Haldar, Sourav; Chaudhuri, Arunima; Gu, Hong; Koeppe, Roger E.; Kombrabail, Mamata; Krishnamoorthy, G.; Chattopadhyay, Amitabha

    2012-01-01

    The linear ion channel peptide gramicidin serves as an excellent prototype for monitoring the organization, dynamics and function of membrane-spanning channels. The tryptophan residues in gramicidin channels are crucial for establishing and maintaining the structure and function of the channel in the membrane bilayer. In order to address the basis of differential importance of tryptophan residues in gramicidin channel, we monitored the effects of pairwise substitution of two of the four grami...

  7. Protein thermal denaturation is modulated by central residues in the protein structure network.

    Science.gov (United States)

    Souza, Valquiria P; Ikegami, Cecília M; Arantes, Guilherme M; Marana, Sandro R

    2016-03-01

    Network structural analysis, known as residue interaction networks or graphs (RIN or RIG, respectively) or protein structural networks or graphs (PSN or PSG, respectively), comprises a useful tool for detecting important residues for protein function, stability, folding and allostery. In RIN, the tertiary structure is represented by a network in which residues (nodes) are connected by interactions (edges). Such structural networks have consistently presented a few central residues that are important for shortening the pathways linking any two residues in a protein structure. To experimentally demonstrate that central residues effectively participate in protein properties, mutations were directed to seven central residues of the β-glucosidase Sfβgly (β-d-glucoside glucohydrolase; EC 3.2.1.21). These mutations reduced the thermal stability of the enzyme, as evaluated by changes in transition temperature (Tm ) and the denaturation rate at 45 °C. Moreover, mutations directed to the vicinity of a central residue also caused significant decreases in the Tm of Sfβgly and clearly increased the unfolding rate constant at 45 °C. However, mutations at noncentral residues or at surrounding residues did not affect the thermal stability of Sfβgly. Therefore, the data reported in the present study suggest that the perturbation of the central residues reduced the stability of the native structure of Sfβgly. These results are in agreement with previous findings showing that networks are robust, whereas attacks on central nodes cause network failure. Finally, the present study demonstrates that central residues underlie the functional properties of proteins. PMID:26785700

  8. Attachment process in subsequent strokes and residual channel luminosity between strokes of natural lightning

    Science.gov (United States)

    Tran, M. D.; Rakov, V. A.

    2015-12-01

    We examined high-speed video and electric field records of 23 subsequent strokes following the previous stroke channel in three natural negative lightning flashes, which were obtained at the Lightning Observatory in Gainesville (LOG), Florida. Five strokes exhibited faintly luminous formations (FLFs) occurring in a single, pre-return-stroke frame and ranging from 130 to 908 m in length between the lower end of downward leader and the prospective strike point. The FLFs were inferred to be not streamers (as in first strokes) but manifestations of an increase in conduction current in the defunct channel between the leader and ground in response to the increasing electric field produced by the descending leader. Further, in eight strokes, we observed residual channel luminosity persisting over many frames (for 4.7 to 18 ms), through the pre-return-stroke frame. The residual luminosity was apparently associated with a stronger channel heating and a larger channel radius (and hence a lower temperature decay rate), both associated with the relatively long preceding continuing current. Presence of either FLF or residual channel luminosity did not appear to significantly influence the mode and velocity of propagation of the descending leader.

  9. Proximate Composition and Collagen Concentration of Processing Residue of Channel Catfish

    Science.gov (United States)

    Residues (including heads, skin, viscera, frames, and trimmings) from the channel catfish Ictalurus punctatus processing industry have generally been made into catfish meal and catfish oil that are used in animal feeds. There may be more efficient uses for these materials, such as producing collagen...

  10. Do cysteine residues regulate transient receptor potential canonical type 6 (TRPC6) channel protein expression?

    DEFF Research Database (Denmark)

    Thilo, Florian; Liu, Ying; Krueger, Katharina;

    2012-01-01

    The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed that patie......The regulation of calcium influx through transient receptor potential canonical type 6 channel is mandatory for the activity of human monocytes. We submit the first evidence that cysteine residues of homocysteine or acetylcysteine affect TRPC6 expression in human monocytes. We observed...... that patients with chronic renal failure had significantly elevated homocysteine levels and TRPC6 mRNA expression levels in monocytes compared to control subjects. We further observed that administration of homocysteine or acetylcysteine significantly increased TRPC6 channel protein expression compared...

  11. Novel residues lining the CFTR chloride channel pore identified by functional modification of introduced cysteines.

    Science.gov (United States)

    Fatehi, Mohammad; Linsdell, Paul

    2009-04-01

    Substituted cysteine accessibility mutagenesis (SCAM) has been used widely to identify pore-lining amino acid side chains in ion channel proteins. However, functional effects on permeation and gating can be difficult to separate, leading to uncertainty concerning the location of reactive cysteine side chains. We have combined SCAM with investigation of the charge-dependent effects of methanethiosulfonate (MTS) reagents on the functional permeation properties of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels. We find that cysteines substituted for seven out of 21 continuous amino acids in the eleventh and twelfth transmembrane (TM) regions can be modified by external application of positively charged [2-(trimethylammonium)ethyl] MTS bromide (MTSET) and negatively charged sodium [2-sulfonatoethyl] MTS (MTSES). Modification of these cysteines leads to changes in the open channel current-voltage relationship at both the macroscopic and single-channel current levels that reflect specific, charge-dependent effects on the rate of Cl(-) permeation through the channel from the external solution. This approach therefore identifies amino acid side chains that lie within the permeation pathway. Cysteine mutagenesis of pore-lining residues also affects intrapore anion binding and anion selectivity, giving more information regarding the roles of these residues. Our results demonstrate a straightforward method of screening for pore-lining amino acids in ion channels. We suggest that TM11 contributes to the CFTR pore and that the extracellular loop between TMs 11 and 12 lies close to the outer mouth of the pore. PMID:19381710

  12. Single residue substitutions that change the gating properties of a mechanosensitive channel in Escherichia coli

    Science.gov (United States)

    Blount, P.; Sukharev, S. I.; Schroeder, M. J.; Nagle, S. K.; Kung, C.

    1996-01-01

    MscL is a channel that opens a large pore in the Escherichia coli cytoplasmic membrane in response to mechanical stress. Previously, we highly enriched the MscL protein by using patch clamp as a functional assay and cloned the corresponding gene. The predicted protein contains a largely hydrophobic core spanning two-thirds of the molecule and a more hydrophilic carboxyl terminal tail. Because MscL had no homology to characterized proteins, it was impossible to predict functional regions of the protein by simple inspection. Here, by mutagenesis, we have searched for functionally important regions of this molecule. We show that a short deletion from the amino terminus (3 amino acids), and a larger deletion of 27 amino acids from the carboxyl terminus of this protein, had little if any effect in channel properties. We have thus narrowed the search of the core mechanosensitive mechanism to 106 residues of this 136-amino acid protein. In contrast, single residue substitutions of a lysine in the putative first transmembrane domain or a glutamine in the periplasmic loop caused pronounced shifts in the mechano-sensitivity curves and/or large changes in the kinetics of channel gating, suggesting that the conformational structure in these regions is critical for normal mechanosensitive channel gating.

  13. Isovector coupling channel and central properties of the charge density distribution in heavy spherical nuclei

    Indian Academy of Sciences (India)

    S Haddad

    2010-09-01

    The influence of the isovector coupling channel on the central depression parameter and the central value of the charge density distribution in heavy spherical nuclei was studied. The isovector coupling channel leads to about 50% increase of the central depression parameter, and weakens the dependency of both central depression parameter and central density on the asymmetry, impressively contributing to the semibubble form of the charge density distribution in heavy nuclei, and increasing the probability of larger nuclei with higher proton numbers and higher neutron-to-proton ratios stable.

  14. Isovector coupling channel and central properties of the charge density distribution in heavy spherical nuclei

    International Nuclear Information System (INIS)

    The influence of the isovector coupling channel on the central depression parameter and the central value of the charge density distribution in heavy spherical nuclei was studied. The isovector coupling channel leads to about 50% increase of the central depression parameter, and weakens the dependency of both central depression parameter and the central density on the asymmetry, impressively contributing to the semibubble form of the charge density distribution in heavy nuclei, and increasing the probability of larger nuclei with higher proton numbers and higher neutron-to-proton ratios stable. (author)

  15. Residual Weeds of Processing Sweet Corn in the North Central Region

    Science.gov (United States)

    Knowledge of weed community structure in vegetable crops of the North Central Region (NCR) is poor. To characterize weed composition of species persisting in sweet corn to harvest, hereafter called residual weeds, 175 sweet corn fields were surveyed in Illinois, Minnesota, and Wisconsin from 2005 to...

  16. Impact of river-tide dynamics on the residual water level slope and residual sediment transport in the Pearl River channel networks

    Science.gov (United States)

    Cai, Huayang; Zhang, Zihao; Yang, Qingshu; Ou, Suying

    2016-04-01

    Large-scale delta systems, such as the Rhine-Meuse delta, the Mississippi River delta, the Mekong delta, the Yangtze delta and the Pearl River delta etc., usually feature a typical channel networks, where individual channels are interrelated through a networks system, resulting in both longitudinal and transverse variations of residual water level slope (averaged over a lunar day) caused by the river-tide interplay. Enhancing our insight of river-tide dynamics in these channel networks has vital importance for the protection and management of estuarine environment since river-tide interplay is closely related to sediment transport, water quality, water utilization and estuarine ecosystem. In this study, we investigate the impact of river-tide dynamics on the temporal-spatial changes of flow and suspended sediment load in terms of residual water level slope and residual sediment transport in the Pearl River channel networks, which is one of the complex channel networks in the world. Making use of a nonstationary harmonic analysis (NS_TIDE), the continuous time series observations of velocity covering a spring-neap cycle in 1999 (representing flood season) and 2001 (representing dry season) collected from around 60 stations in the Pearl River channel networks have been used to extract the temporal-spatial changes in residual velocity and tidal properties (including amplitudes and phases) as a function of variable river flow debouching into the delta. On the basis of harmonic analysis, the tidally averaged friction is decomposed into contributions made by riverine forcing alone, river-tide interaction and tidal asymmetry using Chebyshev polynomials approach. It is shown that river flow enhances friction via river-tide interaction, which increases the residual water level slope that influences the distribution of suspended sediment load in the Pearl River channel networks.

  17. Computational identification of residues that modulate voltage sensitivity of voltage-gated potassium channels

    Directory of Open Access Journals (Sweden)

    Li Bin

    2005-08-01

    Full Text Available Abstract Background Studies of the structure-function relationship in proteins for which no 3D structure is available are often based on inspection of multiple sequence alignments. Many functionally important residues of proteins can be identified because they are conserved during evolution. However, residues that vary can also be critically important if their variation is responsible for diversity of protein function and improved phenotypes. If too few sequences are studied, the support for hypotheses on the role of a given residue will be weak, but analysis of large multiple alignments is too complex for simple inspection. When a large body of sequence and functional data are available for a protein family, mature data mining tools, such as machine learning, can be applied to extract information more easily, sensitively and reliably. We have undertaken such an analysis of voltage-gated potassium channels, a transmembrane protein family whose members play indispensable roles in electrically excitable cells. Results We applied different learning algorithms, combined in various implementations, to obtain a model that predicts the half activation voltage of a voltage-gated potassium channel based on its amino acid sequence. The best result was obtained with a k-nearest neighbor classifier combined with a wrapper algorithm for feature selection, producing a mean absolute error of prediction of 7.0 mV. The predictor was validated by permutation test and evaluation of independent experimental data. Feature selection identified a number of residues that are predicted to be involved in the voltage sensitive conformation changes; these residues are good target candidates for mutagenesis analysis. Conclusion Machine learning analysis can identify new testable hypotheses about the structure/function relationship in the voltage-gated potassium channel family. This approach should be applicable to any protein family if the number of training examples and

  18. Analysis of inter-residue contacts reveals folding stabilizers in P-loops of potassium, sodium, and TRPV channels.

    Science.gov (United States)

    Korkosh, V S; Zhorov, B S; Tikhonov, D B

    2016-05-01

    The family of P-loop channels includes potassium, sodium, calcium, cyclic nucleotide-gated and TRPV channels, as well as ionotropic glutamate receptors. Despite vastly different physiological and pharmacological properties, the channels have structurally conserved folding of the pore domain. Furthermore, crystallographic data demonstrate surprisingly similar mutual disposition of transmembrane and membrane-diving helices. To understand determinants of this conservation, here we have compared available high-resolution structures of sodium, potassium, and TRPV1 channels. We found that some residues, which are in matching positions of the sequence alignment, occur in different positions in the 3D alignment. Surprisingly, we found 3D mismatches in well-packed P-helices. Analysis of energetics of individual residues in Monte Carlo minimized structures revealed cyclic patterns of energetically favorable inter- and intra-subunit contacts of P-helices with S6 helices. The inter-subunit contacts are rather conserved in all the channels, whereas the intra-subunit contacts are specific for particular types of the channels. Our results suggest that these residue-residue contacts contribute to the folding stabilization. Analysis of such contacts is important for structural and phylogenetic studies of homologous proteins. PMID:26646260

  19. Functional Expression of an Arachnid Sodium Channel Reveals Residues Responsible for Tetrodotoxin Resistance in Invertebrate Sodium Channels*

    OpenAIRE

    Du, Yuzhe; Nomura, Yoshiko; Liu, Zhiqi; Huang, Zachary Y.; Dong, Ke

    2009-01-01

    Tetrodotoxin (TTX) is a potent blocker of voltage-gated sodium channels, but not all sodium channels are equally sensitive to inhibition by TTX. The molecular basis of differential TTX sensitivity of mammalian sodium channels has been largely elucidated. In contrast, our knowledge about the sensitivity of invertebrate sodium channels to TTX remains poor, in part because of limited success in functional expression of these channels. In this study, we report the functional characterization in X...

  20. Qualitative approach to residual hazard from the 2013 flood effects in the Garonne River (Val d'Aran, Central Pyrenees)

    Science.gov (United States)

    Garcia-Silvestre, Marta; Victoriano-Lamariano, Ane; Furdada-Bellavista, Gloria

    2015-04-01

    The Val d'Aran is a region located in the central, axial part of the Pyrenees. The Garona River, the main river that drains it, produces relatively frequent flood events. The last significant flood occurred in June 2013 and it caused extensive damages, as well as a large impact on the media. Based on the 2013 flood effects, a qualitative approach to the residual hazard was performed in order to understand the characteristics of the main zones that were affected and, therefore, may be affected in the future. Two representative sectors along the Garona River were chosen for the study: Arties-Vielha and Era Bordeta-Les stretches. The qualitative approach to the residual hazard has been performed considering that the study of the landforms and the flood effects can give orientation to identify the major flood prone areas. The residual hazard is considered as the hazard that remains even when effective mitigation measures to minimize flood processes are in place. The geomorphology in quasi-natural conditions provides information about the natural dynamic of the river. The geomorphology was studied by analysing the landforms from the 1956 aerial pictures that indicate fluvial processes of the area in quasi-natural conditions. Comparing the effects and flooded areas with the fluvial geomorphology and ancient maps, the most significant flood prone areas can be predicted for future episodes. Administration agencies (CHE, ACA) considered the return-period of this flood lower than 50 years. For this low to medium frequency event, two main types of flood effects were identified: erosions and overflows. Erosions were much more significant than overflows. Regarding to erosions, different cases were found: 1) anthropically narrowed channel stretches recovered their original width; 2) the erosions along the river coincided mostly with landfills that nowadays occupy the floodplain; 3) anthropically deviated stretches recovered their natural paths. Furthermore, these erosions caused

  1. Distribution of pesticide residues within homes in central New York State.

    Science.gov (United States)

    Obendorf, S K; Lemley, A T; Hedge, A; Kline, A A; Tan, K; Dokuchayeva, T

    2006-01-01

    Residues for 17 pesticides were analyzed in 41 households in central New York State that represented farm, rural, and urban houses. Samples were taken in both summer and winter of 2000-2001 from the same households from four locations; family room carpet; adjacent smooth floor; flat tabletop surface; and settled dust collected in a Petri dish on a tabletop. Pesticide residues were analyzed to identity factors that influence both the transport into and the redistribution of pesticides in the indoor environment. Differences were observed between the various pesticides and pesticide classifications relative to location within and between households as well as by season. Variations in the pesticide residues were related to a number of factors. Higher residues were observed in the farm households, particularly in summer, with the highest amount observed for chloropyrifos in carpet (33 microg/m2). For many pesticides, the frequency of detection and the amount of residues were higher in summer, which relates to usage patterns in agriculture and horticulture; however, larger amounts of insecticides such as mecoprop, resmethrin, and tetramethrin were found on flat surfaces in winter, indicating household use and possible redistribution within the home. Distribution patterns suggest that routines within a household may cause high variation in residues; these practices include indoor pets and treatment for fleas and ticks, use of termiticides, and fastidiousness of occupants. Frequency of pesticide detection was highest in carpet for both summer and winter for all households, indicating that carpets hold pesticides over time. Adsorbent fibrous materials such as textiles hold pesticides by macro- and micro-occlusion in their complex structures. Amounts of pesticide residue were higher in carpets than on smooth floors, particularly for rural farm households where the farmer was a certified pesticide applicator. The maximum amount of pesticide residue on a smooth floor surface

  2. Organochlorine and metal residues in royal terns nesting on the central Texas coast

    Science.gov (United States)

    King, K.A.; LeFever, C.A.; Mulhern, B.M.

    1983-01-01

    Royal Tern eggs collected from Pelican and Sundown islands on the central Texas coast in 1978 contained relatively low levels of organochlorine and metal pollutants. DDE and PCBs were found most frequently, but levels were below those known to have an adverse effect on avian reproduction and survival. Average metal residues did not vary significantly between study areas, and with the possible exception of mercury, were present only at background levels. Shells of eggs collected in 1978 were no thinner than eggshells collected before 1947. There was a significant imporvement in mean eggshell thickness from 1970 to 1978 and a corresponding decline in DDE and PCB residues. No deformed or abnormal young were observed. Although elevated levels of industrial contaminants were reported in sediments and sea grasses of Corpus Christi Bay, little of those contaminants appear to have accumulated in the Royal Tern.

  3. Comparative ecobalancing accounting of semi-central house heat supply from wood residues

    International Nuclear Information System (INIS)

    In 2008 almost 40 percent of the German final energy demand was used for room heating and hot water supply. To decrease environmental burdens and to save fossil resources a restructuring of the heating sector is needed. Therefore legislation enforces higher insulation standards of buildings and a more frequent use of renewable energies as well as heating networks. Wood as a renewable and storable energy source is an attractive fuel. However, it must be used as efficiently as possible because of limited wood supplies. Connecting buildings via a heating network is a good option since bigger heating plants can operate at higher efficiencies than small heaters. However, the higher insulation standards of the buildings often oppose the construction of a heating network, because heating networks work best with high energy demands and low network lengths. Therefore the environmental and economic feasibility of new heating networks needs to be checked beforehand. This thesis explores the environmental burdens of different semi- centralized heating networks using wood residues as fuel. A semi- centralized heating network is a network with no more than 500 customers and a heating plant with less than 5 MWth. While wood residues are used in the base load plant, peak load is covered by a gas heating plant. As a method to analyze the potential environmental burdens of the heat supply a life cycle assessment according to ISO 14040/44 is used. Opposed to former life cycle assessment studies, construction and operation of the network is included in the assessment. Even though the environmental impacts of the semi- centralized heating from wood residues are dominated by the heat supply, an observation of the impacts solely at the heating plant is not sufficient. By varying the boundary conditions of the heating network two main contributors to the environmental impacts are found. In addition to the heat production at the plant the type of the buildings in the settlement has a huge

  4. A conserved residue cluster that governs kinetics of ATP-dependent gating of Kir6.2 potassium channels

    DEFF Research Database (Denmark)

    Zhang, Roger S; Wright, Jordan; Pless, Stephan Alexander;

    2015-01-01

    elements that control the kinetics of ATP-dependent regulation of KATP (Kir6.2 + SUR1) channels using rapid concentration jumps. WT Kir6.2 channels re-open after rapid washout of ATP with a time constant of approximately 60 ms. Extending similar kinetic measurements to numerous mutants revealed fairly...... modest effects on gating kinetics despite significant changes in ATP sensitivity and open probability. However, we identified a pair of highly conserved neighboring amino acids (Trp68, Lys170) that control the rate of channel opening and inhibition in response to ATP. Paradoxically, mutations of Trp68 or...... Lys170 markedly slow the kinetics of channel opening (500 ms and 700 ms for Trp68Leu and Lys170Asn, respectively), while increasing channel open probability. Examining the functional effects of these residues using phi-value analysis revealed a steep negative slope. This finding implies that these...

  5. Centrally extended residual symmetries in the presence of a constant EM background

    Energy Technology Data Exchange (ETDEWEB)

    Toppan, F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: toppan@cbpf.br

    2001-12-01

    In this talk I discuss the properties of the symmetry algebra (denominated 'residual symmetry') of a QFT in the presence of a non-vanishing, constant, electro-magnetic background. It is shown that this problem can be formulated and solved on a purely Lie-algebra ground (it is model-independent). One of its simplest consequences consists in recovering the central extension in the commutator of the translations, associated with the abelian U(1) charge. For illustrative purposes the case of the (2+1)-dimensional Poincare invariant QFTs coupled with a constant external EM background is discussed in detail. The deformed (and gauge-fixing dependent) surviving Poincare generators are explicitly computed. In the generic case the residual symmetry algebra is isomorphic to u(1)+P{sub c}(2), where P{sub c}(2) is the centrally extended 2-dimensional Poincare algebra. The connection with the Noncommutative Field Theories is briefly mentioned. A short discussion concerning the possible physical implications and the outline of the forthcoming research is given. (author)

  6. Cavity residue leucine 95 and channel residues glutamine 204, aspartic acid 211, and phenylalanine 269 of toluene o-xylene monooxygenase influence catalysis.

    Science.gov (United States)

    Kurt, Cansu; Sönmez, Burcu; Vardar, Nurcan; Yanık-Yıldırım, K Cansu; Vardar-Schara, Gönül

    2016-09-01

    Structural analysis of toluene-o-xylene monooxygenase (ToMO) hydroxylase revealed the presence of three hydrophobic cavities, a channel, and a pore leading from the protein surface to the active site. Here, saturation mutagenesis was used to investigate the catalytic roles of alpha-subunit (TouA) second cavity residue L95 and TouA channel residues Q204, D211, and F269. By testing the substrates toluene, phenol, nitrobenzene, and/or naphthalene, these positions were found to influence the catalytic activity of ToMO. Several regiospecific variants were identified from TouA positions Q204, F269, and L95. For example, TouA variant Q204H had the regiospecificity of nitrobenzene changed significantly from 30 to 61 % p-nitrophenol. Interestingly, a combination of mutations at Q204H and A106V altered the regiospecificity of nitrobenzene back to 27 % p-nitrophenol. TouA variants F269Y, F269P, Q204E, and L95D improved the meta-hydroxylating capability of nitrobenzene by producing 87, 85, 82, and 77 % m-nitrophenol, respectively. For naphthalene oxidation, TouA variants F269V, Q204A, Q204S/S222N, and F269T had the regiospecificity changed from 16 to 9, 10, 23, and 25 % 2-naphthol, respectively. Here, two additional TouA residues, S222 and A106, were also identified that may have important roles in catalysis. Most of the isolated variants from D211 remained active, whereas having a hydrophobic residue at this position appeared to diminish the catalytic activity toward naphthalene. The mutational effects on the ToMO regiospecificity described here suggest that it is possible to further fine tune and engineer the reactivity of multicomponent diiron monooxygenases toward different substrates at positions that are relatively distant from the active site. PMID:27311562

  7. Large teleseismic P-wave residuals observed at the Alban Hills volcano, Central Italy

    Directory of Open Access Journals (Sweden)

    H. Mahadeva Iyer

    1994-06-01

    Full Text Available We collected teleseismic waveforms from a digital microseismic network deployed by the Istituto Nazionale di Geofisica (ING in collaboration with the U.S. Geological Survey (USGS, on the Alban Hills Quaternary volcano during the 1989-1990 seismic swann. About 50 events were recorded by the network, 30 of them by at least 4 stations. We analysed the data in order to image crustal heterogeneities beneath the volcano. The results show large delay time residuals up to - 1 second for stations located on the volcano with respect to station CP9 of the National Seismic Network located about 20 km to the east, on the Apennines. This suggests that the whole area overlies a broad low-velocity region. Although the ray coverage is not very dense, we model the gross seismic structure beneath the volcano by inverting the teleseismic relative residuals with the ACH technique. The main features detected by tbc inversion are a low-velocity zone beneath the southwestern fiank of tbc volcano, and a high-velocity region beneath the center. The depth extension of these anomalous zones ranges between 5 and 16 km. The correspondence between the low-velocity region and the most recent activity of the volcano (- 0.027 Ma leads us to infer the presence of a still hot magmatic body in the crust beneath the southwestern side of the volcano, whereas the central part overlies the older and colder high-velocity volcanic roots related to the previous central activity (0.7 to 0.3 Ma.

  8. The K+ channel opener 1-EBIO potentiates residual function of mutant CFTR in rectal biopsies from cystic fibrosis patients.

    Directory of Open Access Journals (Sweden)

    Eva K Roth

    Full Text Available BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF. Previous studies demonstrated that the K⁺ channel opener 1-ethyl-2-benzimidazolone (1-EBIO potentiates CFTR-mediated Cl⁻ secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl⁻ secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl⁻ secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl⁻ secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl⁻ secretion by 39.2±6.7% (P<0.001 via activation of basolateral Ca²⁺-activated and clotrimazole-sensitive KCNN4 K⁺ channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl⁻ secretion in tissues with residual CFTR function by 44.4±11.5% (P<0.001, but had no effect on tissues lacking CFTR-mediated Cl⁻ conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl⁻secretion in native CF tissues expressing CFTR mutants with residual Cl⁻ channel function by activation of basolateral KCNN4 K⁺ channels that increase the driving force for luminal Cl⁻ exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF.

  9. Effects of maize cultivation on nitrogen and phosphorus loadings to drainage channels in Central Chile.

    Science.gov (United States)

    Corradini, Fabio; Nájera, Francisco; Casanova, Manuel; Tapia, Yasna; Singh, Ranvir; do Salazar, Osval

    2015-11-01

    There are concerns about the impact of maize cultivation with high applications of nitrogen (N) and phosphorus (P) on water quality in surface waters in Mediterranean Central Chile. This study estimated the contribution of N and P from maize fields to nearby drainage channels and evaluated the effects in water quality. An N and P budget was drawn up for three fields managed with a maize-fallow system, El Maitén (20.7 ha), El Naranjal (14.9 ha) and El Caleuche (4.2 ha), and water quality variables (pH, EC, dissolved oxygen, total solids, turbidity, NO3-N, NH4-N, PO4(3-), COD, total N, total P and sulphate) were monitored in nearby drainage channels. The N and P balances for the three fields indicated a high risk of N and P non-point source pollution, with fertiliser management, soil texture and climate factors determining the temporal variations in water quality parameters. Elevated levels of NH4-N and PO4(3-) in the drainage channels were usually observed during the winter period, while NO3- concentrations did not show a clear tendency. The results suggest that excessive slurry application during winter represents a very high risk of N and P runoff to drainage channels. Overall, great emphasis must be placed on good agronomic management of fields neighbouring drainage channels, including accurately calculating N and P fertiliser rates and establishing mitigation measures. PMID:26490735

  10. Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity

    Directory of Open Access Journals (Sweden)

    Li-Min Yang

    2013-02-01

    Full Text Available MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic “emergency release valve,” is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.

  11. Channel adjustments to historical disturbances along the lower Brazos and Sabine Rivers, south-central USA

    Science.gov (United States)

    Heitmuller, Franklin T.

    2014-01-01

    Historical channel adjustments are documented and discussed in context with anthropogenic disturbances along two meandering, coastal plain rivers - the lower Brazos and Sabine Rivers in the south-central United States. Hard-copy streamflow-measurement notes of the U.S. Geological Survey were utilized to render historical cross sections (1925-2007) at nine gauging stations, which were complemented with repeat photographs and flood-frequency analysis to assess trajectories of channel change and interpret causative mechanisms. Downstream- and upstream-propagating disturbances caused episodes of channel-bed incision and aggradation at different locations for distinct time periods along both rivers. Incision associated with upstream dams is detected, but channels are compensated downstream with sediment inputs from lateral channel migration and tributaries. In one case, temporary aggradation along the Brazos River at Waco was likely caused by a combination of dam construction and regional soil erosion. Channel-bed incision on the lowermost Brazos River is unrelated to dams, but is associated with instream aggregate extraction, possibly in conjunction with downstream channelization. On the Sabine River, extensive aggradation during the 1930s might be associated with logging activities (1880s-1930s), but whether the cause is pervasive regional-scale hillslope erosion or local-scale mill-site activities is indeterminate. Following passage of this sediment, the river generally recovered to pre-disturbance conditions and has exhibited stability despite a mainstem reservoir. Translation of this sediment slug is attenuated by a transition to a flood-prone, distributary-dominated system downstream of the Holocene-Pleistocene terrace onlap position. Additional findings include cross-channel hingepoints separating thalweg incision from simultaneous point-bar or bank accretion at meander bends, which indicates channel adjustment occurs along non-cohesive beds in preference to

  12. Centrally acting non-narcotic antitussives prevent hyperactivity in mice: Involvement of GIRK channels.

    Science.gov (United States)

    Soeda, Fumio; Fujieda, Yoshiko; Kinoshita, Mizue; Shirasaki, Tetsuya; Takahama, Kazuo

    2016-05-01

    We have previously reported that centrally acting non-narcotic antitussives inhibited G protein-coupled inwardly rectifying potassium (GIRK) channel-activated currents, and that the antitussives had multiple pharmacological actions on various models of intractable brain diseases in rodents. In this study, the question of whether these antitussives inhibit drug-induced hyperactivity in mice was investigated. Antitussives, such as cloperastine and tipepidine, at cough suppressant doses, inhibited an increase in ambulation of mice neonatally treated with 6-hydroxydopamine. In addition, all antitussives studied inhibited an increase in methamphetamine-induced hyperactivity in mice. Methylphenidate, which is used for treatment of ADHD, inhibited 6-hydroxydopamine-lesion-induced, but not methamphetamine-induced, hyperactivity in mice. By the rota-rod test, the drugs had little effect on motor coordination of the hyperactive mice. Significant correlation was found between the ameliorating effects of antitussives on methamphetamine-induced hyperactivity and their inhibitory actions on GIRK channel currents (coefficient factor, 0.998). Furthermore, tertiapin, a GIRK channel blocker, prevented an increase in methamphetamine-induced hyperactivity of mice. These results demonstrated that antitussive drugs (cloperastine, tipepidine and caramiphen) possessing inhibitory action on GIRK channels inhibit drug-induced hyperactivity in mice, suggesting that such antitussives may potentially be therapeutic for patients with ADHD. PMID:26892760

  13. Decomposition, nitrogen and carbon mineralization from food and cover crop residues in the central plateau of Haiti.

    Science.gov (United States)

    Lynch, M J; Mulvaney, M J; Hodges, S C; Thompson, T L; Thomason, W E

    2016-01-01

    Cover crops are a major focus of conservation agriculture efforts because they can provide soil cover and increase nutrient availability after their mineralization in cropping systems. To evaluate the effect of residue type and placement on rate of decomposition and carbon (C) and nitrogen (N) mineralization, residues from two food crops, maize (Zea mays L.) and common bean (Phaseolus vulgaris L.), and two promising cover crops, sunn hemp (Crotalaria juncea L.) and sorghum sudangrass (Sorghum bicolor [L.] Moench x S. bicolor var. Sudanese [Piper] Stapf) were used in a litterbag study in the Central Plateau region of Haiti from May to September, 2013. Residues were placed in litterbags at a rate equivalent to 3.25 Mg residue ha(-1) either on the soil surface or buried at 15 cm to represent a tilled and no-tillage system, respectively. Initial C:N ratios were: maize > common bean > sorghum sudangrass > sunn hemp. Highest residue mass loss rates and C and N mineralization generally occurred in the reverse order. Overall, surface-placed residues decomposed more slowly with 40 and 17 % of initial residue mass of surface and buried residues, respectively, remaining at 112 days. Carbon and N mineralization was higher when residues were buried. Net N mineralization of buried residues was 0.12, 0.07, 0.06, and 0.03 g N g residue(-1) for sunn hemp, sorghum sudangrass, maize, and common bean, respectively over 112 days. To achieve the goal of increasing nutrient supply while maintaining year-round cover, a combination of grass and legume cover crops may be required with benefits increasing over multiple seasons. PMID:27429883

  14. Phosphorylation of K[superscript +] Channels at Single Residues Regulates Memory Formation

    Science.gov (United States)

    Vernon, Jeffrey; Irvine, Elaine E.; Peters, Marco; Jeyabalan, Jeshmi; Giese, K. Peter

    2016-01-01

    Phosphorylation is a ubiquitous post-translational modification of proteins, and a known physiological regulator of K[superscript +] channel function. Phosphorylation of K[superscript +] channels by kinases has long been presumed to regulate neuronal processing and behavior. Although circumstantial evidence has accumulated from behavioral studies…

  15. Investigation of through thickness residual stress distribution in equal channel angular rolled Al 5083 alloy by layer removal technique and X-ray diffraction

    OpenAIRE

    Mahmoodi, M; Sedighi, M.; Tanner, D.A

    2012-01-01

    peer-reviewed The layer removal technique and the X-ray diffraction method have been employed to evaluate the residual stresses through the thickness of aluminum alloy 5083 processed by equal channel angular rolling (ECAR). ECAR is a severe plastic deformation process that introduces shear deformation to sheet metals. The process has been completed on 2 mm thick strips passed three times through die channels in a continuous manner. In this work, the profile of residual stresses was quantit...

  16. On the east-west asymmetry of the central residual intensities and other fraunhofer line parameters

    International Nuclear Information System (INIS)

    Fraunhofer line parameters of the Sun are investigated from the centre to the limb of the solar disk. Observational profiles of 13 Fraunhofer lines in two spectral ranges (6880 and 6980 A) were derived from the photoelectric tracings taken with the doublepass (''double monochromator'') solar spectrograph of the Pulkovo Observatory. The tracings were made in Summer and Autumn 1963 and cover the minimum of the 19 solar 11--year cycle and the beginning of the new cycle. The observations of both the east and west limbs with the spectrograph slit perpendicular to the radius of the solar disk became possible up to μ=cos THETA=0.158 (THETA is the angle between the line of sight and the solar radius at the point of observation). The tracings of some Fraunhofer lines showed systematic and real differences in profile parameters at the east and west limbs. In particular, central residual intensities, which can be measured more accurately than the halfwidth and the equivalent width of an absorption line, are at the same μ, slightly higher at the west limb of the solar disk than at the east one. For the group of lines under consideration, this effect becomes stronger with the increase of lines' intensities. It is noted, that this ''east-west asymmetry'' of the Fraunhofer line parameters may be due to a horizontal motion of matter of the large-scale field of the solar atmosphere

  17. Computational identification of residues that modulate voltage sensitivity of voltage-gated potassium channels

    OpenAIRE

    Li Bin; Gallin Warren J

    2005-01-01

    Abstract Background Studies of the structure-function relationship in proteins for which no 3D structure is available are often based on inspection of multiple sequence alignments. Many functionally important residues of proteins can be identified because they are conserved during evolution. However, residues that vary can also be critically important if their variation is responsible for diversity of protein function and improved phenotypes. If too few sequences are studied, the support for ...

  18. Entrance channel effects on the evaporation residue yields in reactions leading to the $^{220}$Th compound nucleus

    CERN Document Server

    Kim, Kyungil; Mandaglio, Giuseppe; Giardina, Giorgio; Kim, Youngman

    2014-01-01

    The evaporation residue yields from compound nuclei $^{220}$Th formed in the $^{16}$O+$^{204}$Pb, $^{40}$Ar+$^{180}$Hf, $^{82}$Se+$^{138}$Ba, $^{124}$Sn+$^{96}$Zr reactions are analyzed to study the entrance channel effects by comparison of the capture, fusion and evaporation residue cross sections calculated by the combined dinuclear system (DNS) and advanced statistical models. The difference between evaporation residue (ER) cross sections can be related to the stages of compound nucleus formation or/and at its surviving against fission. The sensitivity of the both stages in the evolution of DNS up to the evaporation residue formation to the angular momentum of DNS is studied. The difference between fusion excitation functions are explained by the hindrance to complete fusion due to the larger intrinsic fusion barrier $B^*_{\\rm fus}$ for the transformation of the DNS into a compound nucleus and the increase of the quasifission contribution due to the decreasing of quasifission barrier $B_{\\rm qf}$ as a func...

  19. AQP4 plasma membrane trafficking or channel gating is not significantly modulated by phosphorylation at C-terminal serine residues

    DEFF Research Database (Denmark)

    Assentoft, Mette; Larsen, Brian R; Olesen, Emma T B;

    2014-01-01

    . Phosphorylation of aquaporins can regulate plasma membrane localization and, possibly, the unit water permeability via gating of the AQP channel itself. In vivo phosphorylation of six serine residues in the COOH terminus of AQP4 has been detected by mass spectrometry: Ser(276), Ser(285), Ser(315), Ser(316), Ser......Aquaporin 4 (AQP4) is the predominant water channel in the mammalian brain and is mainly expressed in the perivascular glial endfeet at the brain-blood interface. AQP4 serves as a water entry site during brain edema formation, and regulation of AQP4 may therefore be of therapeutic interest...... at the plasma membrane of transfected C6 cells being similar between the wild-type (WT) and mutant forms of AQP4. Activation of protein kinases A, C, and G in primary astrocytic cultures did not affect the plasma membrane abundance of AQP4. The unit water permeability was determined for the mutant AQP4s upon...

  20. The evaluation of residual resource of the technological channels of the 1-st ChNPP's unit

    International Nuclear Information System (INIS)

    The result of study of the technological channels (TC) of the 1-st Chernobyl NPP's unit after 18 years of operation are analyzed in this work. It is showed that zirconium alloy of TC operated at normal conditions has satisfactory plastic and strength properties; hydrogen concentration doesn't exceed 60 ppm; the joint devices have safety factor more 2 even at presence of microcracks. The conclusion is done that residual resource of normal operating TC after 18 years of service doesn't still exhaust

  1. Single-channel SCAM Identifies Pore-lining Residues in the First Extracellular Loop and First Transmembrane Domains of Cx46 Hemichannels

    OpenAIRE

    KRONENGOLD, J.; Trexler, E B; Bukauskas, F.F.; Bargiello, T A; Verselis, V K

    2003-01-01

    Gap junction (GJ) channels provide an important pathway for direct intercellular transmission of signaling molecules. Previously we showed that fixed negative charges in the first extracellular loop domain (E1) strongly influence charge selectivity, conductance, and rectification of channels and hemichannels formed of Cx46. Here, using excised patches containing Cx46 hemichannels, we applied the substituted cysteine accessibility method (SCAM) at the single channel level to residues in E1 to ...

  2. The Central domain of RyR1 is the transducer for long-range allosteric gating of channel opening.

    Science.gov (United States)

    Bai, Xiao-Chen; Yan, Zhen; Wu, Jianping; Li, Zhangqiang; Yan, Nieng

    2016-09-01

    The ryanodine receptors (RyRs) are intracellular calcium channels responsible for rapid release of Ca(2+) from the sarcoplasmic/endoplasmic reticulum (SR/ER) to the cytoplasm, which is essential for the excitation-contraction (E-C) coupling of cardiac and skeletal muscles. The near-atomic resolution structure of closed RyR1 revealed the molecular details of this colossal channel, while the long-range allosteric gating mechanism awaits elucidation. Here, we report the cryo-EM structures of rabbit RyR1 in three closed conformations at about 4 Å resolution and an open state at 5.7 Å. Comparison of the closed RyR1 structures shows a breathing motion of the cytoplasmic platform, while the channel domain and its contiguous Central domain remain nearly unchanged. Comparison of the open and closed structures shows a dilation of the S6 tetrahelical bundle at the cytoplasmic gate that leads to channel opening. During the pore opening, the cytoplasmic "O-ring" motif of the channel domain and the U-motif of the Central domain exhibit coupled motion, while the Central domain undergoes domain-wise displacement. These structural analyses provide important insight into the E-C coupling in skeletal muscles and identify the Central domain as the transducer that couples the conformational changes of the cytoplasmic platform to the gating of the central pore. PMID:27468892

  3. Disponibilidade de biomassa florestal residual para combustão na central termoeléctrica de Sines

    OpenAIRE

    Simas, Filipa Camacho da Silva Pinto e

    2013-01-01

    A presente dissertação consistiu na avaliação da disponibilidade de biomassa florestal residual para utilização como combustível na central termoeléctrica de Sines, para produção de electricidade. Por se tratar de uma central termoeléctrica com elevadas emissões de CO2 e pelas condições favoráveis de localização face à obtenção de biomassa, pretendeu-se quantificar e avaliar o potencial energético da biomassa florestal residual disponível de forma a substituir futuramente, parte do combust...

  4. The lending channel and budget balance: empirical evidences from Central and Eastern European economies

    Directory of Open Access Journals (Sweden)

    Bogdan-Gabriel MOINESCU

    2013-03-01

    Full Text Available The study aims to deepen the analysis on the indirect dependence of government budget balance on private sector credit flow in the countries of Central and Eastern Europe. The added value of this approach consists of two elements. First, the analysis suggests developing the traditional analytical framework of assessing risks to public finance stability by including second round effects of negative fiscal impulses on credit to private sector during recession periods. Second, the study provides empirical evidence on the importance of economic growth transmission channel for the impact of credit accelerator effects on primary deficit. At the same time, nonperforming loans channel proved to be insignificant, especially in relation to the persistency of last year’s budget deficit and the effects of budget allocations pro-cyclicality. However, loan portfolio quality seems to be more relevant in the case of public debt service, through its influence on the evolution of the yield on long-term government securities that is closely related to sovereign risk premium. Nevertheless, strengthening the financial safety net by the introduction of resolution funds will most probably break the link investors saw between credit portfolio quality and the impending increase in budget spending. This expected development across not only CEE countries, but at the EU level also, will facilitate the isolation of sovereign risk premium from non-performing loans’ dynamics.

  5. Mitigation of hazards from future lahars from Mount Merapi in the Krasak River channel near Yogyakarta, central Java

    Science.gov (United States)

    Ege, John R.; Sutikno

    1983-01-01

    Procedures for reducing hazards from future lahars and debris flows in the Krasak River channel near Yogyakarta, Central Java, Indonesia, include (1) determining the history of the location, size, and effects of previous lahars and debris flows, and (2) decreasing flow velocities. The first may be accomplished by geologic field mapping along with acquiring information by interviewing local residents, and the second by increasing the cross sectional area of the river channel and constructing barriers in the flow path.

  6. Simulation of residual oil displacement in a sinusoidal channel with the lattice Boltzmann method

    CERN Document Server

    Otomo, Hiroshi; Hazlett, Randy; Li, Yong; Staroselsky, Ilya; Zhang, Raoyang; Chen, Hudong

    2016-01-01

    We simulate oil slug displacement in a sinusoidal channel in order to validate computational models and algorithms for multi-component flow. This case fits in the gap between fully realistic cases characterized by complicated geometry and academic cases with simplistic geometry. Our computational model is based on the lattice Boltzmann method and allows for variation of physical parameters such as wettability and viscosity. The effect of variation of model parameters is analyzed, in particular via comparison with analytical solutions. We discuss the requirements for accurate solution of the oil slug displacement problem.

  7. Entrance channel effects in the production of evaporation residues in heavy ion fusion reactions

    International Nuclear Information System (INIS)

    Near-barrier excitation functions have been measured for the evaporation-residue (ER) production and fission in the 12C + 204,206,208Pb and 48Ca + 168,170Er systems that lead to the compound nuclei 216,218,220Ra*. A pronounced suppression of the ER production is observed for the more symmetric combinations 48Ca + 168,170Er. In the analysis, these data have been compared with the similar ones obtained in very asymmetric and more symmetric combinations leading to the same but less fissile and strongly compound nuclei. We relate this suppression of the ER production, observed for some of more symmetric systems, to the quasi-fission effect manifested in the fusion of massive nuclei

  8. Determination of activity by gamma spectrometry of radionuclides present in drums of residues generated in nuclear centrals

    International Nuclear Information System (INIS)

    The generation of radioactive residuals in nuclear centrals as CNA I (Atucha I Nuclear Central) and CNE (Embalse Nuclear Central) makes that the measurement of those radionuclides has been a previous stage to the waste management. A method used in those nuclear centrals it is the gamma spectrometry with HPGe detectors, previous to the immobilization of the residual in a cemented matrix, with this the contact with the external agents and its possible dispersion to the atmosphere in the short term is avoided. The ARN (Nuclear Regulatory Authority) of Argentina it carries out periodically intercomparisons and evaluations of the measurement and procedures systems used in the nuclear power stations for the correct measurement and determination of activity of radioactive residuals by gamma spectrometry. In this work an independent method of measurement is exposed to the nuclear power stations. To determine the activity of the residuals by gamma spectrometry deposited in drums, it is required of the precise knowledge of the efficiency curve for such geometry and matrix. Due to the RNA doesn't have a pattern of these characteristics, a mathematical model has been used to obtain this efficiency curve. For it, it is necessary to determine previously: 1) the geometric efficiency or solid angle sustained by the source-detector system (drum-detector) applying a mathematical model described in this work. 2) To estimate the auto-attenuation factor that present the photons in the cemented matrix, these calculations are carried out with a simple equation and its are verified with the Micro Shield 6.10 program. The container commonly used by these nuclear power stations its are drums for 220 liters constructed with SAE 1010 steel and with a thickness of 0.127 cm, with an approximate weight 7.73 Kg., internal diameter of 57.1 cm, and height: 87 cm. The results obtained until the moment register a discrepancy from 5 to 10% with relationship to the measurements carried out by the

  9. Soil erosion and organic matter variations for central Great Plains cropping systems under residue removal

    Science.gov (United States)

    The diversity of geo-climatic land bases and potential feedstocks within the United States Central Great Plains (CGP) requires sustainable production that provides optimal resource utilization while maintaining or enhancing localized soil and environmental quality as much as possible. This study exa...

  10. The role of vegetation in the formation of anabranching channels in an ephemeral river, Northern plains, arid central Australia

    Science.gov (United States)

    Tooth, Stephen; Nanson, Gerald C.

    2000-10-01

    As the distribution and abundance of vegetation in drylands is often controlled by the greater availability of water along river channels, riparian vegetation has the potential to influence significantly dryland river form, process and behaviour. This paper demonstrates how a small indigenous shrub, the inland teatree (Melaleuca glomerata), influences the formation and maintenance of anabranching channels in a reach of the ephemeral Marshall River, Northern Plains, arid central Australia. Here, the Marshall is characterized by ridge-form anabranching, where water and sediment are routed through subparallel, multiple channels of variable size which occur within a typically straight channel-train. Channels are separated by channel-train ridges - narrow, flow-aligned, vegetated features - or by wider islands. By providing a substantial element of boundary roughness, dense stands of teatrees growing on channel beds or atop the ridges and islands influence flow velocities, flow depths and sediment transport, resulting in flow diversion, bank and floodplain erosion, and especially sediment deposition. Ridges and islands represent a continuum of forms, and their formation and development can be divided into a three-stage sequence involving teatree growth and alluvial sedimentation.1Teatrees colonize a flat, sandy channel bed, initiating the formation of ridges by lee-side accretion. Individual ridges grow laterally, vertically and longitudinally and maintain a geometrically similar streamlined (lemniscate) form that presents minimum drag.2Individual ridges grow in size, and interact with neighbouring ridges, causing the lemniscate forms to become distorted. Ridges in the lee of other ridges tend to be protected from the erosive effects of floods and survive, whereas individual teatrees or small ridges exposed to flow concentrated between larger ridges, tend to be removed.3organized system of ridge-form anabranches. In the moderate- to low-gradient Marshall River, which is

  11. Residue analysis of organochlorine pesticides in the Mae Klong river of Central Thailand

    International Nuclear Information System (INIS)

    The most natural waterways in Thailand are utilized for conventional agricultures, e.g. irrigation and wastewater discharge. Concentrations of 20 organochlorine pesticides (OCPs) were measured in surface sediments collected from the tributaries of the Mae Klong river during 2003-2005. The sampling sites chosen were nearby the rice paddy which organochlorine pesticides were intensively used for crop cultivation. Solid-liquid extraction technique was used for sediment extraction, and gas chromatography with electron capture detector was applied for pesticides determination. Total concentrations of OCPs found were ranged from 4.12 to 214.91 μg g-1 dw in the first year. In the second year, total residue concentrations in the surface sediments were in the range of 3.26-215.09 μg g-1 dw. Concentrations of pesticides were greater in dry-season rice cultivation period in both sampling years, and heptachlor epoxide was the contaminant found at highest concentration in this study. In addition, the occurrence of some selected contaminants including DDT, DDD and DDE reflects the recent contamination in the study area. This demonstrates not only that the natural waterway was polluted and contained much pesticide residues, but it also illustrates the necessity of a continuous long-term monitoring of the affected environment

  12. Widespread rocky reef occurrence in the central English Channel and the implications for predictive habitat mapping

    Science.gov (United States)

    Diesing, Markus; Coggan, Roger; Vanstaen, Koen

    2009-08-01

    Reefs are one of the marine habitats listed in Annex I of the European Union's Habitats Directive, which aims to establish a coherent European ecological network of Special Areas of Conservation. EU Member States are required to prepare and propose a national list of sites for evaluation under the scheme, but currently the occurrence of reefs in the United Kingdom's nearshore and offshore areas is not well documented. Here we report on our search for rocky reefs in the central English Channel, which unexpectedly revealed an extensive reef system covering an area of 1100 km 2. Prior to our work, it was generally perceived that the seabed in this area comprised mostly gravel, with a few isolated rock outcrops. Our approach to determining the location, extent and character of these reefs incorporated broad, medium and fine-scale analyses over a 3200 km 2 area of seabed, using single- and multi-beam acoustic data, ground-truthed by underwater video and stills imagery. A benthic terrain model was developed in ArcGIS to map topographic features at the broad and medium scales. Biotope assignments were made at the fine scale through detailed analysis of video footage obtained from 30 sampling stations. The study area has a complex geological history and lies at the centre of a major bedload-parting zone. Together, these strongly influence the seabed character and the distribution of biotopes. An integrated assessment of the physical and biological features was used to map the study area to level 4 of the EUNIS habitat classification system. Similar physical conditions exist in other areas of the UK continental shelf, raising the prospect of predicting where other rocky reef systems might occur. In the absence of a co-ordinated national seabed survey programme, such predictions, coupled with interpretation of existing single-beam bathymetry data, can help prioritise areas where limited survey resources could be most effectively deployed.

  13. Study of Channel Morphology and Infill Lithology in the Wilcox Group Central Louisiana Using Seismic Attribute Analysis

    Science.gov (United States)

    Chen, Feng

    The fluvial and deltaic Wilcox Group is a major target for hydrocarbon and coal exploration in northern and central Louisiana. However, the characterization and delineation of fluvial systems is a difficult task due to the variability and complexity of fluvial systems and their internal heterogeneities. Seismic geomorphology is studied by recognizing paleogeographic features in seismic stratal slices, which are seismic images of paleo-depositional surfaces. Seismic attributes, which are extracted along seismic stratal slices, can reveal information that is not readily apparent in raw seismic data. The existence and distribution of fluvial channels are recognized by the channel geomorphology in seismic attributes displayed on stratal slices. The lithologies in the channels are indicated by those seismic attributes that are directly related to the physical properties of rocks. Selected attributes utilized herein include similarity, spectral decomposition, sweetness, relative acoustic impedance, root mean square (RMS) amplitude, and curvature. Co-rendering and Red/Green/Blue (RGB) display techniques are also included to better illuminate the channel geometry and lithology distribution. Hydrocarbons may exist in the channel sand-bodies, but are not explicitly identified herein. Future drilling plans for oil and gas exploration may benefit from the identification of the channels and the lithologies that fill them.

  14. Microstructural analysis of the Greater Himalayan Sequence, Annapurna-Dhaulagiri Himalaya, central Nepal: Channel Flow and Orogen-parallel deformation.

    Science.gov (United States)

    Parsons, A. J.; Phillips, R. J.; Lloyd, G. E.; Searle, M. P.; Law, R. D.

    2014-12-01

    Knowledge of deformation processes that occur in the lithosphere during orogenesis can be gained from microstructural analysis of exhumed terranes and shear zones. Here, we use Crystallographic Preferred Orientation (CPO) and Anisotropy of Magnetic Susceptibility (AMS) data to reveal the kinematic evolution of the metamorphic core of the Himalayan orogen, the Greater Himalayan Sequence (GHS). The Himalayan orogen is commonly explained with models of channel flow, which describe the GHS as a partially molten, rheologically weak mid crustal channel. Extrusion of the channel was facilitated by coeval reverse- and normal-sense shear zones, at the lower and upper channel margins respectively. Whilst many thermobarometric studies support the occurrence of channel flow, the spatial and temporal distribution of strain within the GHS is one aspect of the model that is yet to be fully resolved. We present a quantified strain proxy profile for the GHS in the Annapurna-Dhaulagiri region of central Nepal and compare our results with the kinematic predictions of the channel flow model. Samples were collected along a NS transect through the Kali Gandaki valley of central Nepal for CPO and AMS analysis. Variations in CPO strength are used as a proxy for relative strain magnitude, whilst AMS data provide a proxy for strain ellipsoid shape. Combining this information with field and microstructural observations and thermobarometric constraints reveals the kinematic evolution of the GHS in this region. Low volumes of leucogranite and sillimanite bearing rocks and evidence of reverse-sense overprinting normal-sense shearing at the top of the GHS suggest that channel flow was not as intense as model predictions. Additionally, observed EW mineral lineations and oblate strain ellipsoid proxies in the Upper GHS, indicative of three dimensional flattening and orogen parallel stretching, cannot be explained by current channel flow models. Whilst the results do not refute the occurrence of

  15. Presence and vascular pharmacology of KATP channel subtypes in rat central and peripheral tissues

    DEFF Research Database (Denmark)

    Ploug, Kenneth Beri; Baun, Michael; Hay-Schmidt, Anders;

    2010-01-01

    K(ATP) channel openers are vasodilators and induce headache in normal subjects. We previously identified the Kir6.1/SUR2B K(ATP) channel subtype in major cerebral and dural arteries of rat, pig and man. We hypothesized that craniovascular Kir6.1/SUR2B K(ATP) channels mediate the headache......-inducing effects of K(ATP) channel openers and that a Kir6.1/SUR2B specific blocker might be effective in the treatment of primary headaches such as migraine. Since K(ATP) channels are ubiquitous, we characterized the K(ATP) channel subtypes in major rat cranial and peripheral arteries and organs in order to...... also studied the effects and potencies of a panel of synthetic K(ATP) channel openers and their potential inhibition by the Kir6.1 subunit-specific K(ATP) channel blocker PNU-37883A in segments of the arteries mounted in a wire myograph. Our studies suggest that Kir6.1/SUR2B forms the major functional...

  16. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

    Science.gov (United States)

    Amodeo, Giuseppe Federico; Scorciapino, Mariano Andrea; Messina, Angela; De Pinto, Vito; Ceccarelli, Matteo

    2014-01-01

    Voltage Dependent Anion-selective Channels (VDACs) are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs) Molecular Dynamics (MD) simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities. PMID:25084457

  17. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

    Directory of Open Access Journals (Sweden)

    Giuseppe Federico Amodeo

    Full Text Available Voltage Dependent Anion-selective Channels (VDACs are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs Molecular Dynamics (MD simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities.

  18. The Protonation State of the Glu-71/Asp-80 Residues in the KcsA Potassium Channel: A First-Principles QM/MM Molecular Dynamics Study

    OpenAIRE

    Bucher, Denis; Guidoni, Leonardo; Rothlisberger, Ursula

    2007-01-01

    Although a few x-ray structures of the KcsA K+ channel have been crystallized several issues concerning the mechanisms of the ionic permeation and the protonation state of the selectivity filter ionizable side chains are still open. Using a first-principles quantum mechanical/molecular mechanical simulation approach, we have investigated the protonation state of Glu-71 and Asp-80, two important residues located in the vicinity of the selectivity filter. Results from the dynamics show that a p...

  19. Investigation of thermal energy transport from an anisotropic central heating element to the adjacent channels: A multipoint flux approximation

    International Nuclear Information System (INIS)

    Highlights: • The multipoint flux method is used to solve the problem of heat transfer in anisotropic medium. • The anisotropy results in skewness of the temperature field. • This makes the heat flux to the two channels asymmetric. • The temperature profiles of the coolant in the two channels becomes also different. - Abstract: The problem of heat transfer from a central heating element pressed between two clad plates to cooling channels adjacent and outboard of the plates is investigated numerically. The aim of this work is to highlight the role of thermal conductivity anisotropy of the heating element and/or the encompassing plates on thermal energy transport to the fluid passing through the two channels. When the medium is anisotropic with respect to thermal conductivity; energy transport to the neighboring channels is no longer symmetric. This asymmetry in energy fluxes influence heat transfer to the coolant resulting in different patterns of temperature fields. In particular, it is found that the temperature fields are skewed towards the principal direction of anisotropy. In addition, the heat flux distributions along the edges of the heating element are also different as a manifestation of thermal conductivity anisotropy. Furthermore, the peak temperature at the channel walls change location and magnitude depending on the principal direction of anisotropy. Based on scaling arguments, it is found that, the ratio of width to the height of the heating system is a key parameter which can suggest when one may ignore the effect of the cross-diagonal terms of the full conductivity tensor. To account for anisotropy in thermal conductivity, the method of multipoint flux approximation (MPFA) is employed. Using this technique, it is possible to find a finite difference stencil which can handle full thermal conductivity tensor and in the same time enjoys the simplicity of finite difference approximation. Although the finite difference stencil based on MPFA is

  20. Voltage-dependent and -independent titration of specific residues accounts for complex gating of a ClC chloride channel by extracellular protons.

    Science.gov (United States)

    Niemeyer, María Isabel; Cid, L Pablo; Yusef, Yamil R; Briones, Rodolfo; Sepúlveda, Francisco V

    2009-04-01

    The ClC transport protein family comprises both Cl(-) ion channel and H(+)/Cl(-) and H(+)/NO(3)(-) exchanger members. Structural studies on a bacterial ClC transporter reveal a pore obstructed at its external opening by a glutamate side-chain which acts as a gate for Cl(-) passage and in addition serves as a staging post for H(+) exchange. This same conserved glutamate acts as a gate to regulate Cl(-) flow in ClC channels. The activity of ClC-2, a genuine Cl(-) channel, has a biphasic response to extracellular pH with activation by moderate acidification followed by abrupt channel closure at pH values lower than approximately 7. We have now investigated the molecular basis of this complex gating behaviour. First, we identify a sensor that couples extracellular acidification to complete closure of the channel. This is extracellularly-facing histidine 532 at the N-terminus of transmembrane helix Q whose neutralisation leads to channel closure in a cooperative manner. We go on to show that acidification-dependent activation of ClC-2 is voltage dependent and probably mediated by protonation of pore gate glutamate 207. Intracellular Cl(-) acts as a voltage-independent modulator, as though regulating the pK(a) of the protonatable residue. Our results suggest that voltage dependence of ClC-2 is given by hyperpolarisation-dependent penetration of protons from the extracellular side to neutralise the glutamate gate deep within the channel, which allows Cl(-) efflux. This is reminiscent of a partial exchanger cycle, suggesting that the ClC-2 channel evolved from its transporter counterparts. PMID:19153159

  1. Experimental studies on the impact of ASE noise of single-channel optical amplifiers in central office applications

    Institute of Scientific and Technical Information of China (English)

    zheng zheng(郑铮)

    2004-01-01

    We identified the amplified spontaneous emission-amplified spontaneous emission (ASE-ASE) beat noise from the semiconductor optical amplifier, which has been overlooked in previous studies, as a cause of severe system penalties when it was used to provide single-channel amplification in a dynamic central office environment through experimental studies. Our results pointed out that the ASE-ASE beat noise of the optical amplifier, other than its gain and noise figure, has to be considered to correctly predict its performance in these new applications.

  2. Numerical Model of Channel and Aquatic Habitat Response to Sediment Pulses in Mountain Rivers of Central Idaho

    Science.gov (United States)

    Lewicki, M.; Buffington, J. M.; Thurow, R. F.; Isaak, D. J.

    2006-12-01

    Mountain rivers in central Idaho receive pulsed sediment inputs from a variety of mass wasting processes (side-slope landslides, rockfalls, and tributary debris flows). Tributary debris flows and hyperconcentrated flows are particularly common due to winter "rain-on-snow" events and summer thunderstorms, the effects of which are amplified by frequent wildfire and resultant changes in vegetation, soil characteristics, and basin hydrology. Tributary confluences in the study area are commonly characterized by debris fans built by these repeated sediment pulses, providing long-term controls on channel slope, hydraulics and sediment transport capacity in the mainstem channel network. These long-term impacts are magnified during debris-flow events, which deliver additional sediment and wood debris to the fan and may block the mainstem river. These changes in physical conditions also influence local and downstream habitat for aquatic species, and can impact local human infrastructure (roads, bridges). Here, we conduct numerical simulations using a modified version of Cui's [2005] network routing model to examine bedload transport and debris-fan evolution in medium- sized watersheds (65-570 km2) of south-central Idaho. We test and calibrate the model using data from a series of postfire debris-flow events that occurred from 2003-4. We investigate model sensitivity to different controlling factors (location of the pulse within the stream network, volume of the pulse, and size distribution of the input material). We predict that on decadal time scales, sediment pulses cause a local coarsening of the channel bed in the vicinity of the sediment input, and a wave of downstream fining over several kilometers of the river (as long as the pulse material is not coarser than the stream bed itself). The grain-size distribution of the pulse influences its rate of erosion, the rate and magnitude of downstream fining, and the time required for system recovery. The effects of textural

  3. Oxidation of KCNB1 K~+ channels in central nervous system and beyond

    Institute of Scientific and Technical Information of China (English)

    Federico; Sesti; Xilong; Wu; Shuang; Liu

    2014-01-01

    KCNB1, a voltage-gated potassium(K+) channel that conducts a major delayed rectifier current in the brain, pancreas and cardiovascular system is a key player in apoptotic programs associated with oxidative stress. As a result, this protein represents a bona fide drug target for limiting the toxic effects of oxygen radicals. Until recently the consensus view was that reactive oxygen species trigger a pro-apoptotic surge in KCNB1 current via phosphorylation and SNARE-dependent incorpora-tion of KCNB1 channels into the plasma membrane. However, new evidence shows that KCNB1 can be modified by oxidants and that oxidized KCNB1 channels can directly activate pro-apoptotic signaling pathways. Hence, a more articulated picture of the pro-apoptotic role of KCNB1 is emerging in which the protein induces cell’s death through distinct molecular mechanisms and activation of multiple pathways. In this review article we discuss the diverse functional, toxic and protective roles that KCNB1 channels play in the major organs where they are expressed.

  4. Biogeochemical markers of organic matter along the Wight-Cherbourg transect (central English Channel)

    OpenAIRE

    Ismaili, Mm; Serve, L; Gadel, F.; Lafite, R; Texier, H.

    1999-01-01

    Three cruises on the Wight-Cherbourg transect were undertaken during the FluxManche II Programme in order to study the origin, nature and behaviour of organic matter inputs to the waters of the English Channel. Suspended particulate material (SPM) collected from surface and deep waters at each station was analysed at elemental level for Particulate Organic Carbon and Particulate Organic Nitrogen (POC, PON), at molecular level for main classes of organic compounds using Pyrolysis-Gas Chromatog...

  5. Investigation of thermal energy transport from an anisotropic central heating element to the adjacent channels: A multipoint flux approximation

    KAUST Repository

    Salama, Amgad

    2015-02-01

    The problem of heat transfer from a central heating element pressed between two clad plates to cooling channels adjacent and outboard of the plates is investigated numerically. The aim of this work is to highlight the role of thermal conductivity anisotropy of the heating element and/or the encompassing plates on thermal energy transport to the fluid passing through the two channels. When the medium is anisotropic with respect to thermal conductivity; energy transport to the neighboring channels is no longer symmetric. This asymmetry in energy fluxes influence heat transfer to the coolant resulting in different patterns of temperature fields. In particular, it is found that the temperature fields are skewed towards the principal direction of anisotropy. In addition, the heat flux distributions along the edges of the heating element are also different as a manifestation of thermal conductivity anisotropy. Furthermore, the peak temperature at the channel walls change location and magnitude depending on the principal direction of anisotropy. Based on scaling arguments, it is found that, the ratio of width to the height of the heating system is a key parameter which can suggest when one may ignore the effect of the cross-diagonal terms of the full conductivity tensor. To account for anisotropy in thermal conductivity, the method of multipoint flux approximation (MPFA) is employed. Using this technique, it is possible to find a finite difference stencil which can handle full thermal conductivity tensor and in the same time enjoys the simplicity of finite difference approximation. Although the finite difference stencil based on MPFA is quite complex, in this work we apply the recently introduced experimenting field approach which construct the global problem automatically.

  6. Scanning mutagenesis of the I-II loop of the Cav2.2 calcium channel identifies residues Arginine 376 and Valine 416 as molecular determinants of voltage dependent G protein inhibition

    Directory of Open Access Journals (Sweden)

    Tedford Hugo W

    2010-02-01

    Full Text Available Abstract Direct interaction with the β subunit of the heterotrimeric G protein complex causes voltage-dependent inhibition of N-type calcium channels. To further characterize the molecular determinants of this interaction, we performed scanning mutagenesis of residues 372-387 and 410-428 of the N-type channel α1 subunit, in which individual residues were replaced by either alanine or cysteine. We coexpressed wild type Gβ1γ2 subunits with either wild type or point mutant N-type calcium channels, and voltage-dependent, G protein-mediated inhibition of the channels (VDI was assessed using patch clamp recordings. The resulting data indicate that Arg376 and Val416 of the α1 subunit, residues which are surface-exposed in the presence of the calcium channel β subunit, contribute significantly to the functional inhibition by Gβ1. To further characterize the roles of Arg376 and Val416 in this interaction, we performed secondary mutagenesis of these residues, coexpressing the resulting mutants with wild type Gβ1γ2 subunits and with several isoforms of the auxiliary β subunit of the N-type channel, again assessing VDI using patch clamp recordings. The results confirm the importance of Arg376 for G protein-mediated inhibition and show that a single amino acid substitution to phenylalanine drastically alters the abilities of auxiliary calcium channel subunits to regulate G protein inhibition of the channel.

  7. Analysis and optimization of centralized sequential channel sensing in cognitive radio networks

    OpenAIRE

    Shokri-Ghadikolaei, Hossein; Yaghoubi, Forough; Fischione, Carlo

    2014-01-01

    Effective spectrum sensing strategies enable cognitiveradios to enhance the spectrum efficiency. In this paper,modeling, performance analysis, and optimization of spectrum handoff in a centralized cognitive radio network are studied.More specifically, for a given sensing order, the average throughput of secondary users and average interference level among the secondary and primary users are evaluated for a cognitive radio network with only one secondary user. By aMarkov chain analysis, a netw...

  8. Hydrophobic interaction between contiguous residues in the S6 transmembrane segment acts as a stimuli integration node in the BK channel

    Science.gov (United States)

    Carrasquel-Ursulaez, Willy; Contreras, Gustavo F.; Sepúlveda, Romina V.; Aguayo, Daniel; González-Nilo, Fernando

    2015-01-01

    Large-conductance Ca2+- and voltage-activated K+ channel (BK) open probability is enhanced by depolarization, increasing Ca2+ concentration, or both. These stimuli activate modular voltage and Ca2+ sensors that are allosterically coupled to channel gating. Here, we report a point mutation of a phenylalanine (F380A) in the S6 transmembrane helix that, in the absence of internal Ca2+, profoundly hinders channel opening while showing only minor effects on the voltage sensor active–resting equilibrium. Interpretation of these results using an allosteric model suggests that the F380A mutation greatly increases the free energy difference between open and closed states and uncouples Ca2+ binding from voltage sensor activation and voltage sensor activation from channel opening. However, the presence of a bulky and more hydrophobic amino acid in the F380 position (F380W) increases the intrinsic open–closed equilibrium, weakening the coupling between both sensors with the pore domain. Based on these functional experiments and molecular dynamics simulations, we propose that F380 interacts with another S6 hydrophobic residue (L377) in contiguous subunits. This pair forms a hydrophobic ring important in determining the open–closed equilibrium and, like an integration node, participates in the communication between sensors and between the sensors and pore. Moreover, because of its effects on open probabilities, the F380A mutant can be used for detailed voltage sensor experiments in the presence of permeant cations. PMID:25548136

  9. Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA

    Science.gov (United States)

    Heitmuller, Frank T.; Hudson, Paul F.; Asquith, William H.

    2015-01-01

    The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel morphology. Field surveys of channel topography and boundary composition are coupled with sediment analyses, hydraulic computations, flood-frequency analyses, and geographic information system mapping to discern controls on channel geometry (profile, pattern, and shape) and dimensions along the mixed alluvial-bedrock Llano River and key tributaries. Four categories of channel classification in a downstream direction include: (i) uppermost ephemeral reaches, (ii) straight or sinuous gravel-bed channels in Cretaceous carbonate sedimentary zones, (iii) straight or sinuous gravel-bed or bedrock channels in Paleozoic sedimentary zones, and (iv) straight, braided, or multithread mixed alluvial–bedrock channels with sandy beds in Precambrian igneous and metamorphic zones. Principal findings include: (i) a nearly linear channel profile attributed to resistant bedrock incision checkpoints; (ii) statistically significant correlations of both alluvial sinuosity and valley confinement to relatively high f (mean depth) hydraulic geometry values; (iii) relatively high b (width) hydraulic geometry values in partly confined settings with sinuous channels upstream from a prominent incision checkpoint; (iv) different functional flow categories including frequently occurring events (flood magnitude and noncohesive sandy sediments that collectively minimize development of alluvial bankfull indicators. Collectively, these findings indicate that mixed alluvial–bedrock channels exhibit first-order lithologic controls (lithologic resistance and valley confinement) of channel geometry, second

  10. Identification of Amino Acid Residues in Fibroblast Growth Factor 14 (FGF14) Required for Structure-Function Interactions with Voltage-gated Sodium Channel Nav1.6.

    Science.gov (United States)

    Ali, Syed R; Singh, Aditya K; Laezza, Fernanda

    2016-05-20

    The voltage-gated Na(+) (Nav) channel provides the basis for electrical excitability in the brain. This channel is regulated by a number of accessory proteins including fibroblast growth factor 14 (FGF14), a member of the intracellular FGF family. In addition to forming homodimers, FGF14 binds directly to the Nav1.6 channel C-tail, regulating channel gating and expression, properties that are required for intrinsic excitability in neurons. Seeking amino acid residues with unique roles at the protein-protein interaction interface (PPI) of FGF14·Nav1.6, we engineered model-guided mutations of FGF14 and validated their impact on the FGF14·Nav1.6 complex and the FGF14:FGF14 dimer formation using a luciferase assay. Divergence was found in the β-9 sheet of FGF14 where an alanine (Ala) mutation of Val-160 impaired binding to Nav1.6 but had no effect on FGF14:FGF14 dimer formation. Additional analysis revealed also a key role of residues Lys-74/Ile-76 at the N-terminal of FGF14 in the FGF14·Nav1.6 complex and FGF14:FGF14 dimer formation. Using whole-cell patch clamp electrophysiology, we demonstrated that either the FGF14(V160A) or the FGF14(K74A/I76A) mutation was sufficient to abolish the FGF14-dependent regulation of peak transient Na(+) currents and the voltage-dependent activation and steady-state inactivation of Nav1.6; but only V160A with a concomitant alanine mutation at Tyr-158 could impede FGF14-dependent modulation of the channel fast inactivation. Intrinsic fluorescence spectroscopy of purified proteins confirmed a stronger binding reduction of FGF14(V160A) to the Nav1.6 C-tail compared with FGF14(K74A/I76A) Altogether these studies indicate that the β-9 sheet and the N terminus of FGF14 are well positioned targets for drug development of PPI-based allosteric modulators of Nav channels. PMID:26994141

  11. Presynaptic GABAB receptors reduce transmission at parabrachial synapses in the lateral central amygdala by inhibiting N-type calcium channels.

    Science.gov (United States)

    Delaney, A J; Crane, J W

    2016-01-01

    The nocioceptive information carried by neurons of the pontine parabrachial nucleus to neurons of the lateral division of the central amydala (CeA-L) is thought to contribute to the affective components of pain and is required for the formation of conditioned-fear memories. Importantly, excitatory transmission between parabrachial axon terminals and CeA-L neurons can be inhibited by a number of presynaptic receptors linked to Gi/o-type G-proteins, including α2-adrenoceptors and GABAB receptors. While the intracellular signalling pathway responsible for α2-adrenoceptor inhibition of synaptic transmission at this synapse is known, the mechanism by which GABAB receptors inhibits transmission has not been determined. The present study demonstrates that activation of presynaptic GABAB receptors reduces excitatory transmission between parabrachial axon terminals and CeA-L neurons by inhibiting N-type calcium channels. While the involvement of Gβγ subunits in mediating the inhibitory effects of GABAB receptors on N-type calcium channels is unclear, this inhibition does not involve Gβγ-independent activation of pp60C-src tyrosine kinase. The results of this study further enhance our understanding of the modulation of the excitatory input from parabrachial axon terminals to CeA-L neurons and indicate that presynaptic GABAB receptors at this synapse could be valuable therapeutic targets for the treatment of fear- and pain-related disorders. PMID:26755335

  12. Optimal nuclear magnetic resonance excitation schemes for the central transition of a spin 3/2 in the presence of residual quadrupolar coupling.

    Science.gov (United States)

    Lee, Jae-Seung; Regatte, Ravinder R; Jerschow, Alexej

    2008-12-14

    Optimal control theory is applied for enhancing the intensity of the central peak of a spin 3/2 signal in the presence of a residual quadrupolar coupling. While a maximum enhancement is always possible in the regime omega(rf) control and test these with (23)Na NMR in this regime. In addition to enhancing the intensity of the central transition signal, the satellite peaks can be effectively suppressed, which is a useful feature for the implementation in (23)Na imaging sequences. PMID:19071931

  13. Neutron flux measurement in the central channel (XC1) of TRIGA 14 MW LEU core

    International Nuclear Information System (INIS)

    The full conversion of the 14 MW TRIGA Research Reactor was completed in May 2006 and each step of the conversion was achieved by removal of HEU fuel and replaced by LEU fuel. The operation was accompanied by a large set of theoretical evaluations and physical measurements intended to confirm the performances of gradual conversion. After the core full conversion, a program of measurements and comparisons with previous results of core physics and measurements is underway, allowing data acquisition for normal operation, demonstration of safety and economics of the converted core. Neutron flux spectrum measurements in the XC-1 water-filled channel were performed using multi-foil activation techniques. The neutron spectra and flux are obtained by unfolding from measured reaction rates using SAND II computer code. The integral flux measured value for LEU core and 14 MW reactor power is 4.66x1014 n/cm2s. For standard core the integral neutron flux for 14 MW reactor power was 4.27x1014 n/cm2s. (authors)

  14. Neutron flux measurement in the central channel (XC-1) of TRIGA 14 MW LEU core

    International Nuclear Information System (INIS)

    The TRIGA 14 MW reactor, operated by Institute for Nuclear Research Pitesti, Romania, is a pool type reactor, and has a rectangular shape which holds fuel bundles and is surrounded with beryllium reflectors. Each fuel bundle is composed of 25 nuclear fuel rods. The TRIGA 14 MW reactor was commissioned 28 years ago with HEU fuel rods. The conversion was gradually achieved, starting in February 1992 and completed in March 2006. The full conversion of the 14 MW TRIGA Research Reactor was completed in May 2006 and each step of the conversion was achieved by removal of HEU fuel, replaced by LEU fuel, accompanied by a large set of theoretical evaluation and physical measurements intended to confirm the performances of gradual conversion. After the core full conversion, a program of measurements and comparisons with previous results of core physics and measurements is underway, allowing data acquisition for normal operation, demonstration of safety and economics of the converted core. Neutron flux spectrum measurements in the XC in the XC-1 water 1 water-filled channel were performed using multi multi-foil activation techniques. The neutron spectra and flux are obtained by unfolding from measured reaction rates using SAND II computer code. The integral neutron flux value for LEU core is greater of 13% than for the standard HEU core. Also thermal neutron flux value for converted LEU core is smaller by 0.38% than for the standard HEU core. These differences appear because the foil activation detectors have been irradiated using a pneumatic rabbit having a diameter of 32 mm, whereas foil irradiations in standard HEU core has been performed with a pneumatic rabbit having a diameter of 14 mm, and therefore the neutron spectra in LEU core is less thermalized and the weight of fast neutron is greater

  15. Neutron flux measurement in the central channel (XC-1) of TRIGA 14 MW LEU core

    Energy Technology Data Exchange (ETDEWEB)

    BARBOS, D.; BUSUIOC, P.; ROTH, Cs.; PAUNOIU, C. [Institute for Nuclear Research - ICN Pitesti (Romania)

    2008-10-29

    The TRIGA 14 MW reactor, operated by Institute for Nuclear Research Pitesti, Romania, is a pool type reactor, and has a rectangular shape which holds fuel bundles and is surrounded with beryllium reflectors. Each fuel bundle is composed of 25 nuclear fuel rods. The TRIGA 14 MW reactor was commissioned 28 years ago with HEU fuel rods. The conversion was gradually achieved, starting in February 1992 and completed in March 2006. The full conversion of the 14 MW TRIGA Research Reactor was completed in May 2006 and each step of the conversion was achieved by removal of HEU fuel, replaced by LEU fuel, accompanied by a large set of theoretical evaluation and physical measurements intended to confirm the performances of gradual conversion. After the core full conversion, a program of measurements and comparisons with previous results of core physics and measurements is underway, allowing data acquisition for normal operation, demonstration of safety and economics of the converted core. Neutron flux spectrum measurements in the XC in the XC-1 water 1 water-filled channel were performed using multi multi-foil activation techniques. The neutron spectra and flux are obtained by unfolding from measured reaction rates using SAND II computer code. The integral neutron flux value for LEU core is greater of 13% than for the standard HEU core. Also thermal neutron flux value for converted LEU core is smaller by 0.38% than for the standard HEU core. These differences appear because the foil activation detectors have been irradiated using a pneumatic rabbit having a diameter of 32 mm, whereas foil irradiations in standard HEU core has been performed with a pneumatic rabbit having a diameter of 14 mm, and therefore the neutron spectra in LEU core is less thermalized and the weight of fast neutron is greater.

  16. Deletion of the last five C-terminal amino acid residues of connexin43 leads to lethal ventricular arrhythmias in mice without affecting coupling via gap junction channels.

    Science.gov (United States)

    Lübkemeier, Indra; Requardt, Robert Pascal; Lin, Xianming; Sasse, Philipp; Andrié, René; Schrickel, Jan Wilko; Chkourko, Halina; Bukauskas, Feliksas F; Kim, Jung-Sun; Frank, Marina; Malan, Daniela; Zhang, Jiong; Wirth, Angela; Dobrowolski, Radoslaw; Mohler, Peter J; Offermanns, Stefan; Fleischmann, Bernd K; Delmar, Mario; Willecke, Klaus

    2013-05-01

    The cardiac intercalated disc harbors mechanical and electrical junctions as well as ion channel complexes mediating propagation of electrical impulses. Cardiac connexin43 (Cx43) co-localizes and interacts with several of the proteins located at intercalated discs in the ventricular myocardium. We have generated conditional Cx43D378stop mice lacking the last five C-terminal amino acid residues, representing a binding motif for zonula occludens protein-1 (ZO-1), and investigated the functional consequences of this mutation on cardiac physiology and morphology. Newborn and adult homozygous Cx43D378stop mice displayed markedly impaired and heterogeneous cardiac electrical activation properties and died from severe ventricular arrhythmias. Cx43 and ZO-1 were co-localized at intercalated discs in Cx43D378stop hearts, and the Cx43D378stop gap junction channels showed normal coupling properties. Patch clamp analyses of isolated adult Cx43D378stop cardiomyocytes revealed a significant decrease in sodium and potassium current densities. Furthermore, we also observed a significant loss of Nav1.5 protein from intercalated discs in Cx43D378stop hearts. The phenotypic lethality of the Cx43D378stop mutation was very similar to the one previously reported for adult Cx43 deficient (Cx43KO) mice. Yet, in contrast to Cx43KO mice, the Cx43 gap junction channel was still functional in the Cx43D378stop mutant. We conclude that the lethality of Cx43D378stop mice is independent of the loss of gap junctional intercellular communication, but most likely results from impaired cardiac sodium and potassium currents. The Cx43D378stop mice reveal for the first time that Cx43 dependent arrhythmias can develop by mechanisms other than impairment of gap junction channel function. PMID:23558439

  17. Deep dynamical processes in the central-southern Qinghai-Tibet Plateau—Receiver functions and travel-time residuals analysis of north Hi-Climb

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Teleseismic receiver functions and travel-time residuals along the north Hi-Climb broadband seismic array in the central-southern Qinghai-Tibet Plateau show that the lithosphere structures in the central and western Qinghai-Tibet Plateau are different. In the central Qinghai-Tibet Plateau, the Indian Plate is northward subducted beneath the Qiangtang block and arrives at the greatest depth beneath the central-southern Qiangtang block. The delaminated Indian lithospheric slab remains beneath the central Lhasa block to a depth possibly greater than that of the upper interface of the mantle transform zone. In the western Qinghai-Tibet Plateau, the Indian lithospheric plate is gently northward subducted and may have arrived to the south of Tarim plate. Due to the resistance from the gently northward subduction of the Indian mantle lithosphere in the western Qinghai-Tibet Plateau, the upwelling mantle material be-neath the Qiangtang block moves mostly toward the east to bring about the lateral eastward flow of the deep mantle hot material in the central Qinghai-Tibet Plateau.

  18. Control of the Aquaporin-4 Channel Water Permeability by Structural Dynamics of Aromatic/Arginine Selectivity Filter Residues.

    Science.gov (United States)

    Kitchen, Philip; Conner, Alex C

    2015-11-17

    The aquaporins (AQPs) make up a family of integral membrane proteins that control cellular water flow. Gating of the water channel by conformational changes induced by phosphorylation or protein-protein interactions is an established regulatory mechanism for AQPs. Recent in silico and crystallographic analyses of the structural biology of AQPs suggest that the rate of water flow can also be controlled by small movements of single-amino acid side chains lining the water pore. Here we use measurements of the membrane water permeability of mammalian cells expressing AQP4 mutants to provide the first in vitro evidence in support of this hypothesis. PMID:26512424

  19. Adsorption of charged protein residues on an inorganic nanosheet: Computer simulation of LDH interaction with ion channel

    Science.gov (United States)

    Tsukanov, Alexey A.; Psakhie, Sergey G.

    2016-08-01

    Quasi-two-dimensional and hybrid nanomaterials based on layered double hydroxides (LDH), cationic clays, layered oxyhydroxides and hydroxides of metals possess large specific surface area and strong electrostatic properties with permanent or pH-dependent electric charge. Such nanomaterials may impact cellular electrostatics, changing the ion balance, pH and membrane potential. Selective ion adsorption/exchange may alter the transmembrane electrochemical gradient, disrupting potential-dependent cellular processes. Cellular proteins as a rule have charged residues which can be effectively adsorbed on the surface of layered hydroxide based nanomaterials. The aim of this study is to attempt to shed some light on the possibility and mechanisms of protein "adhesion" an LDH nanosheet and to propose a new direction in anticancer medicine, based on physical impact and strong electrostatics. An unbiased molecular dynamics simulation was performed and the combined process free energy estimation (COPFEE) approach was used.

  20. Comparative ecobalancing accounting of semi-central house heat supply from wood residues; Vergleichende Oekobilanzierung der semi-zentralen Hauswaermebereitstellung aus Holzreststoffen

    Energy Technology Data Exchange (ETDEWEB)

    Biemann, Kirsten

    2015-07-01

    In 2008 almost 40 percent of the German final energy demand was used for room heating and hot water supply. To decrease environmental burdens and to save fossil resources a restructuring of the heating sector is needed. Therefore legislation enforces higher insulation standards of buildings and a more frequent use of renewable energies as well as heating networks. Wood as a renewable and storable energy source is an attractive fuel. However, it must be used as efficiently as possible because of limited wood supplies. Connecting buildings via a heating network is a good option since bigger heating plants can operate at higher efficiencies than small heaters. However, the higher insulation standards of the buildings often oppose the construction of a heating network, because heating networks work best with high energy demands and low network lengths. Therefore the environmental and economic feasibility of new heating networks needs to be checked beforehand. This thesis explores the environmental burdens of different semi- centralized heating networks using wood residues as fuel. A semi- centralized heating network is a network with no more than 500 customers and a heating plant with less than 5 MWth. While wood residues are used in the base load plant, peak load is covered by a gas heating plant. As a method to analyze the potential environmental burdens of the heat supply a life cycle assessment according to ISO 14040/44 is used. Opposed to former life cycle assessment studies, construction and operation of the network is included in the assessment. Even though the environmental impacts of the semi- centralized heating from wood residues are dominated by the heat supply, an observation of the impacts solely at the heating plant is not sufficient. By varying the boundary conditions of the heating network two main contributors to the environmental impacts are found. In addition to the heat production at the plant the type of the buildings in the settlement has a huge

  1. Nanofiltration and sensing of picomolar chemical residues in aqueous solution using an optical porous resonator in a microelectrofluidic channel

    Science.gov (United States)

    Huang, Lei; Guo, Zhixiong

    2012-02-01

    For the first time the use of a porous microresonator placed in a microelectrofluidic system for integrated functions of nanofiltration and sensing of small biomolecules and chemical analytes in extremely dilute solution was proposed and investigated. As an example, aminoglycosides in drug residues in food and livestock products were considered as the trace chemical analyte. The filtration process of the charged analyte in aqueous solution driven by an applied electrical field and the accompanying optical whispering-gallery modes in the resonator are modeled. The dynamic process of adsorption and desorption of the analyte onto the porous matrix is studied. Deposition of the analyte inside the porous structure will alter the material refractive index of the resonator, and thus induce an optical resonance frequency shift. By measuring the optical frequency shift, the analyte concentration as well as the absorption/desorption process can be analyzed. Through an intensive numerical study, a correlation between the frequency shift and the analyte concentration and the applied electrical voltage gradient was obtained. This reveals a linear relationship between the resonance frequency shift and the analyte concentration. The applied electrical voltage substantially enhances the filtration capability and the magnitude of the optical frequency shift, pushing the porous resonator-based sensor to function at the extremely dilute picomolar concentration level for small bio/chemical molecules down to the sub-nanometer scale. Moreover, use of the second-order whispering-gallery mode is found to provide better sensitivity compared with the first-order mode.

  2. Nanofiltration and sensing of picomolar chemical residues in aqueous solution using an optical porous resonator in a microelectrofluidic channel

    International Nuclear Information System (INIS)

    For the first time the use of a porous microresonator placed in a microelectrofluidic system for integrated functions of nanofiltration and sensing of small biomolecules and chemical analytes in extremely dilute solution was proposed and investigated. As an example, aminoglycosides in drug residues in food and livestock products were considered as the trace chemical analyte. The filtration process of the charged analyte in aqueous solution driven by an applied electrical field and the accompanying optical whispering-gallery modes in the resonator are modeled. The dynamic process of adsorption and desorption of the analyte onto the porous matrix is studied. Deposition of the analyte inside the porous structure will alter the material refractive index of the resonator, and thus induce an optical resonance frequency shift. By measuring the optical frequency shift, the analyte concentration as well as the absorption/desorption process can be analyzed. Through an intensive numerical study, a correlation between the frequency shift and the analyte concentration and the applied electrical voltage gradient was obtained. This reveals a linear relationship between the resonance frequency shift and the analyte concentration. The applied electrical voltage substantially enhances the filtration capability and the magnitude of the optical frequency shift, pushing the porous resonator-based sensor to function at the extremely dilute picomolar concentration level for small bio/chemical molecules down to the sub-nanometer scale. Moreover, use of the second-order whispering-gallery mode is found to provide better sensitivity compared with the first-order mode. (paper)

  3. Determination of activity by gamma spectrometry of radionuclides present in drums of residues generated in nuclear centrals; Determinacion de actividad por espectrometria gamma de radionucleidos presentes en tambores de residuos generados en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, J.C.; Fernandez, J. [Autoridad Regulatoria Nuclear, Av. Del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina)]. e-mail: jaguiar@cae.arn.gov.ar

    2006-07-01

    The generation of radioactive residuals in nuclear centrals as CNA I (Atucha I Nuclear Central) and CNE (Embalse Nuclear Central) makes that the measurement of those radionuclides has been a previous stage to the waste management. A method used in those nuclear centrals it is the gamma spectrometry with HPGe detectors, previous to the immobilization of the residual in a cemented matrix, with this the contact with the external agents and its possible dispersion to the atmosphere in the short term is avoided. The ARN (Nuclear Regulatory Authority) of Argentina it carries out periodically intercomparisons and evaluations of the measurement and procedures systems used in the nuclear power stations for the correct measurement and determination of activity of radioactive residuals by gamma spectrometry. In this work an independent method of measurement is exposed to the nuclear power stations. To determine the activity of the residuals by gamma spectrometry deposited in drums, it is required of the precise knowledge of the efficiency curve for such geometry and matrix. Due to the RNA doesn't have a pattern of these characteristics, a mathematical model has been used to obtain this efficiency curve. For it, it is necessary to determine previously: 1) the geometric efficiency or solid angle sustained by the source-detector system (drum-detector) applying a mathematical model described in this work. 2) To estimate the auto-attenuation factor that present the photons in the cemented matrix, these calculations are carried out with a simple equation and its are verified with the Micro Shield 6.10 program. The container commonly used by these nuclear power stations its are drums for 220 liters constructed with SAE 1010 steel and with a thickness of 0.127 cm, with an approximate weight 7.73 Kg., internal diameter of 57.1 cm, and height: 87 cm. The results obtained until the moment register a discrepancy from 5 to 10% with relationship to the measurements carried out by the

  4. Life cycle assessment of post-consumer plastics production from waste electrical and electronic equipment (WEEE) treatment residues in a Central European plastics recycling plant

    Energy Technology Data Exchange (ETDEWEB)

    Wäger, Patrick A., E-mail: patrick.waeger@empa.ch; Hischier, Roland

    2015-10-01

    Plastics play an increasingly important role in reaching the recovery and recycling rates defined in the European WEEE Directive. In a recent study we have determined the life cycle environmental impacts of post-consumer plastics production from mixed, plastics-rich WEEE treatment residues in the Central European plant of a market-leading plastics recycler, both from the perspective of the customers delivering the residues and the customers buying the obtained post-consumer recycled plastics. The results of our life cycle assessments, which were extensively tested with sensitivity analyses, show that from both perspectives plastics recycling is clearly superior to the alternatives considered in this study (i.e. municipal solid waste incineration (MSWI) and virgin plastics production). For the three ReCiPe endpoint damage categories, incineration in an MSWI plant results in an impact exceeding that of the examined plastics recycling facility each by about a factor of 4, and the production of virgin plastics has an impact exceeding that of the post-consumer recycled (PCR) plastics production each by a factor of 6–10. On a midpoint indicator level the picture is more differentiated, showing that the environmental impacts of the recycling options are lower by 50% and more for almost all impact factors. While this provides the necessary evidence for the environmental benefits of plastics recycling compared to existing alternatives, it can, however, not be taken as conclusive evidence. To be conclusive, future research will have to address the fate of hazardous substances in the outputs of such recycling systems in more detail. - Highlights: • LCA of plastics production from plastics-rich WEEE treatment residues • Multiple stakeholder perspectives addressed via different research questions • Plastics production from WEEE treatment residues clearly superior to alternatives • Robust results as demonstrated by extensive sensitivity analyses.

  5. Life cycle assessment of post-consumer plastics production from waste electrical and electronic equipment (WEEE) treatment residues in a Central European plastics recycling plant

    International Nuclear Information System (INIS)

    Plastics play an increasingly important role in reaching the recovery and recycling rates defined in the European WEEE Directive. In a recent study we have determined the life cycle environmental impacts of post-consumer plastics production from mixed, plastics-rich WEEE treatment residues in the Central European plant of a market-leading plastics recycler, both from the perspective of the customers delivering the residues and the customers buying the obtained post-consumer recycled plastics. The results of our life cycle assessments, which were extensively tested with sensitivity analyses, show that from both perspectives plastics recycling is clearly superior to the alternatives considered in this study (i.e. municipal solid waste incineration (MSWI) and virgin plastics production). For the three ReCiPe endpoint damage categories, incineration in an MSWI plant results in an impact exceeding that of the examined plastics recycling facility each by about a factor of 4, and the production of virgin plastics has an impact exceeding that of the post-consumer recycled (PCR) plastics production each by a factor of 6–10. On a midpoint indicator level the picture is more differentiated, showing that the environmental impacts of the recycling options are lower by 50% and more for almost all impact factors. While this provides the necessary evidence for the environmental benefits of plastics recycling compared to existing alternatives, it can, however, not be taken as conclusive evidence. To be conclusive, future research will have to address the fate of hazardous substances in the outputs of such recycling systems in more detail. - Highlights: • LCA of plastics production from plastics-rich WEEE treatment residues • Multiple stakeholder perspectives addressed via different research questions • Plastics production from WEEE treatment residues clearly superior to alternatives • Robust results as demonstrated by extensive sensitivity analyses

  6. Pertussis toxin modulation of sodium channels in the central neurons of cyhalothrin-resistant and cyhalothrin-susceptible cotton bollworm, Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    QIANG ZHAO; DE-LING KONG; BING-JUN HE; YAN-QIANG LIU; XIAN-LIN FAN; AN-XI LIU

    2007-01-01

    Pertussis toxin (PTX) inhibits the activation of the α-subunit of the inhibitory heterotrimeric G-proteins (Gαi/o) and modulates voltage-gated sodium channels, which may be one of the primary targets of pyrethroids. To investigate the potential mechanisms of agricultural pests resistance to pyrethroid insecticides, we examined the modulations by PTX on sodium channels in the central neurons of the 3rd-4th instar larvae of cyhalothrin-resistant (Cy-R) and cyhalothrin-susceptible (Cy-S) Helicoverpa armigera by the whole-cell patch-clamp technique.The isolated neurons were cultured for 12-16 h in an improved L15 insect culture medium with or without PTX (400 ng/mL). The results showed that both the Cy-R and Cy-S sodium channels exhibited fast kinetics and tetrodotoxin (TTX) sensitivity. The Cy-R sodium channels exhibited not only altered gating properties, including a 8.88-mV right shift in voltage-dependent activation (V0.5act) and a 6.54-mV right shift in voltage-dependent inactivation (V0.5inact), but also a reduced peak in sodium channel density (Idensity) (55.2% of that in Cy-S neurons). Cy-R sodium channels also showed low excitability, as evidenced by right shift of activation potential (Vacti) by 5-10 mV and peak potential (Vpeak) by 20 mV. PTX exerted significant effects on Cy-S sodium channels,reducing sodium channel density by 70.04%, right shifting V0.5act by 14.41 mV and V0.5inact by 9.38 mV. It did not cause any significant changes of the parameters mentioned above in the Cy-R sodium channels. The activation time (Tpeak) from latency to peak at peak voltage and the fast inactivation time constant (τinact) in both Cy-S and Cy-R neurons were not affected. The results suggest that cotton bollworm resistant to pyrethroid insecticides involves not only mutations and allosteric alterations of voltage-gated sodium channels, but also might implicate perturbation of PTX-sensitive Gαi/o-coupled signaling transduction pathways.

  7. Rapid effects of estrogen on G protein-coupled receptor activation of potassium channels in the central nervous system (CNS).

    Science.gov (United States)

    Kelly, Martin J; Qiu, Jian; Wagner, Edward J; Rønnekleiv, Oline K

    2002-12-01

    Estrogen rapidly alters the excitability of hypothalamic neurons that are involved in regulating numerous homeostatic functions including reproduction, stress responses, feeding and motivated behaviors. Some of the neurons include neurosecretory neurons such as gonadotropin-releasing hormone (GnRH) and dopamine neurons, and local circuitry neurons such as proopiomelanocortin (POMC) and gamma-aminobutyric acid (GABA) neurons. We have elucidated several non-genomic pathways through which the steroid alters synaptic responses in these hypothalamic neurons. We have examined the modulation by estrogen of the coupling of various receptor systems to inwardly-rectifying and small-conductance, Ca(2+)-activated K(+) (SK) channels using intracellular sharp-electrode and whole-cell recording techniques in hypothalamic slices from ovariectomized female guinea pigs. Estrogen rapidly uncouples mu-opioid receptors from G protein-gated inwardly-rectifying K(+) (GIRK) channels in POMC neurons and GABA(B) receptors from GIRK channels in dopamine neurons as manifested by a reduction in the potency of mu-opioid and GABA(B) receptor agonists to hyperpolarize their respective cells. This effect is blocked by inhibitors of protein kinase A (PKA) and protein kinase C (PKC). In addition, after 24h following steroid administration in vivo, the GABA(B)/GIRK channel uncoupling observed in GABAergic neurons of the preoptic area is associated with reduced agonist efficacy. Conversely, estrogen enhances the efficacy of alpha(1)-adrenergic receptor agonists to inhibit apamin-sensitive SK currents in these preoptic GABAergic neurons, and does so in both a rapid and sustained fashion. Finally, we observed a direct, steroid-induced hyperpolarization of GnRH neurons. These findings indicate a richly complex yet coordinated steroid modulation of K(+) channel activity in hypothalamic (POMC, dopamine, GABA, GnRH) neurons that are involved in regulating numerous homeostatic functions. PMID:12650715

  8. Life cycle assessment of post-consumer plastics production from waste electrical and electronic equipment (WEEE) treatment residues in a Central European plastics recycling plant.

    Science.gov (United States)

    Wäger, Patrick A; Hischier, Roland

    2015-10-01

    Plastics play an increasingly important role in reaching the recovery and recycling rates defined in the European WEEE Directive. In a recent study we have determined the life cycle environmental impacts of post-consumer plastics production from mixed, plastics-rich WEEE treatment residues in the Central European plant of a market-leading plastics recycler, both from the perspective of the customers delivering the residues and the customers buying the obtained post-consumer recycled plastics. The results of our life cycle assessments, which were extensively tested with sensitivity analyses, show that from both perspectives plastics recycling is clearly superior to the alternatives considered in this study (i.e. municipal solid waste incineration (MSWI) and virgin plastics production). For the three ReCiPe endpoint damage categories, incineration in an MSWI plant results in an impact exceeding that of the examined plastics recycling facility each by about a factor of 4, and the production of virgin plastics has an impact exceeding that of the post-consumer recycled (PCR) plastics production each by a factor of 6-10. On a midpoint indicator level the picture is more differentiated, showing that the environmental impacts of the recycling options are lower by 50% and more for almost all impact factors. While this provides the necessary evidence for the environmental benefits of plastics recycling compared to existing alternatives, it can, however, not be taken as conclusive evidence. To be conclusive, future research will have to address the fate of hazardous substances in the outputs of such recycling systems in more detail. PMID:26022405

  9. Polycyclic aromatic hydrocarbons residues in Gentile di maiale, a smoked meat product typical of some mountain areas in Latina province (Central Italy

    Directory of Open Access Journals (Sweden)

    Giuseppe Carrabs

    2014-05-01

    Full Text Available Gentile di maiale is a typical meat product prepared in some traditional plants of Latina Province (Central Italy. It is obtained from dehydration, salting, smoking and ripening of swine rectum. Aim of this study was to evaluate the influence of the traditional smoking process on polycyclic aromatic hydrocarbons (PAHs content by means of high-performance liquid chromatographic/fluorescence detection. Polycyclic aromatic hydrocarbons detected in 8 samples of raw material (swine rectum and samples of smoked gentile were: benzo[a]anthracene, chrisene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a] pyrene, benzo[a,h]anthracene. Their residues were detected in all samples of finished product. European Regulation 835/2011 established two levels of PAHs content in meat products. According to first levels, in force until September 2014, only 2 out of 8 samples exceeded legal limit. According to the subsequent, more restrictive, limits all samples would be non-compliant. An improvement and a standardisation of traditional smoking procedures are recommended.

  10. A Central Cysteine Residue Is Essential for the Thermal Stability and Function of SUMO-1 Protein and SUMO-1 Peptide-Protein Conjugates.

    Science.gov (United States)

    Drobecq, Hervé; Boll, Emmanuelle; Sénéchal, Magalie; Desmet, Rémi; Saliou, Jean-Michel; Lacapère, Jean-Jacques; Mougel, Alexandra; Vicogne, Jérôme; Melnyk, Oleg

    2016-06-15

    SUMOylation constitutes a major post-translational modification (PTM) used by the eukaryote cellular machinery to modulate protein interactions of the targeted proteins. The small ubiquitin-like modifier-1 (SUMO-1) features a central and conserved cysteine residue (Cys52) that is located in the hydrophobic core of the protein and in tight contact with Phe65, suggesting the occurrence of an S/π interaction. To investigate the importance of Cys52 on SUMO-1 thermal stability and biochemical properties, we produced by total chemical synthesis SUMO-1 or SUMO-1 Cys52Ala peptide-protein conjugates featuring a native isopeptidic bond between SUMO-1 and a peptide derived from p53 tumor suppressor protein. The Cys52Ala modification perturbed SUMO-1 secondary structure and resulted in a dramatic loss of protein thermal stability. Moreover, the cleavage of the isopeptidic bond by the deconjugating enzyme Upl1 was significantly less efficient than for the wild-type conjugate. Similarly, the in vitro SUMOylation of RanGap1 by E1/E2 conjugating enzymes was significantly less efficient with the SUMO-1 C52A analog compared to wild-type SUMO-1. These data demonstrate the critical role of Cys52 in maintaining SUMO-1 conformation and function and the importance of keeping this cysteine intact for the study of SUMO-1 protein conjugates. PMID:27195426

  11. Estrogen modulation of G-protein-coupled receptor activation of potassium channels in the central nervous system.

    Science.gov (United States)

    Kelly, Martin J; Qiu, Jian; Rønnekleiv, Oline K

    2003-12-01

    Estrogen rapidly alters the excitability of hypothalamic neurons that are involved in regulating numerous homeostatic functions including reproduction, stress responses, feeding, and motivated behaviors. Neurosecretory neurons, such as gonadotropin-releasing hormone (GnRH) and dopamine neurons, and local circuitry neurons, such as pro-opiomelanocortin (POMC) and gamma-aminobutyric acid (GABA) neurons, are among those involved. We have identified membrane-initiated, rapid-signaling pathways through which 17beta-estradiol (E(2)) alters synaptic responses in these neurons using whole-cell patch recording in hypothalamic slices from ovariectomized female guinea pigs. E(2) rapidly uncouples micro -opioid and GABA(B) receptors from G-protein-gated inwardly rectifying K(+) (GIRK) channels in POMC and dopamine neurons as manifested by a reduction in the potency of micro -opioid and GABA(B) receptor agonists to activate these channels. These effects are mimicked by the selective E(2) receptor modulators raloxifene and 4OH-tamoxifen, the membrane impermeable E(2)-bovine serum albumin (BSA), but not by 17alpha-estradiol. Furthermore, the anti-estrogen ICI 182,780 antagonizes these rapid effects of E(2). Inhibitors of phospholipase C, protein kinase C, and protein kinase A block the actions of E(2), indicating that the E(2) receptor is G-protein-coupled to activation of this cascade. Conversely, estrogen enhances the efficacy of alpha1-adrenergic receptor agonists to inhibit apamin-sensitive small-conductance, Ca(2+)-activated K(+) (SK) currents in preoptic GABAergic neurons; it does so in both a rapid and sustained fashion. Finally, we observed a direct, steroid-induced hyperpolarization of GnRH neurons. These findings indicate that E(2) can modulate K(+) channels in hypothalamic (POMC, dopamine, GABA, GnRH) neurons that are involved in regulating numerous homeostatic functions through multiple intracellular signaling pathways. PMID:14993035

  12. Brain-Derived Neurotrophic Factor Inhibits Calcium Channel Activation, Exocytosis, and Endocytosis at a Central Nerve Terminal

    OpenAIRE

    Baydyuk, Maryna; Wu, Xin-sheng; He, Liming; Wu, Ling-Gang

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) is a neurotrophin that regulates synaptic function and plasticity and plays important roles in neuronal development, survival, and brain disorders. Despite such diverse and important roles, how BDNF, or more generally speaking, neurotrophins affect synapses, particularly nerve terminals, remains unclear. By measuring calcium currents and membrane capacitance during depolarization at a large mammalian central nerve terminal, the rat calyx of Held, we re...

  13. Towards an integrated assessment of the impacts of forest residue mulching following wildfire in eucalypt plantations in north-central Portugal

    Science.gov (United States)

    Keizer, Jan Jacob; Abrantes, Nelson; Bastos, Ana; Brandsma, Micha; Campos, Isabel; Faria, Silvia; Malvar, Maruxa; Martins, Martinho; João Oliveira, Maria; Pimpão, Gabriel; Prats, Sergio; Puga, João; Ribeiro, Cristina; Rocha, João; Santos, Liliana; Serpa, Dalila; Silva, Flávio; Silva, Tiago; Valente, Sandra; Vieira, Diana

    2016-04-01

    In the framework of the EU-FP7 project RECARE (www.recare-project.eu) and, in particular, its WP6, the University of Aveiro partner has recently started testing two measures against the soil threat of post-fire erosion by water in an area in north-central Portugal, close to Coimbra that burnt during the summer of 2015. These measures - mulching with forest slash residues and contour ploughing - had been selected by the local and external stakeholders involved in the project, through two subsequent stakeholder workshops. While contour ploughing has still not taken place, the mulching was already carried out, using residues from eucalypt plantations as the burnt areas was dominated by eucalypt plantations, and applying them in a homogeneous fashion at two contrasting application rates, i.e. a "standard" rate of approximately 10 Mg ha-1 and a "reduced" rate of about 3 Mg ha-1. The standard rate was selected for having proved effective in reducing post-fire runoff and erosion in previous field studies in the region (Prats et al., 2012, 2014, 2015a), while the reduced rate had been found to be nearly as effective as the standard rate in a recent study in the hydraulic laboratory of the University of Coimbra (Prats et al., 2015b). Unlike the referred prior studies, however, the present study will also assess the impacts of mulching on two other soil threats - i.e. decline in soil organic matter and in soil biodiversity - and, ultimately, will compare the two measures in terms of their consequences for soil-based ecosystem services, using the framework being developed by RECARE (Schwilch et al. in Stolte et al., 2016). The proposed presentation will show the first results on the effects of the two mulch application rates on post-fire runoff as well as the associated losses of sediments, organic matter/C and nutrients (N, P), and on selected indicators of soil biological activity and diversity. Prats et al., 2015a (in press). LD&D (doi: 10.1002/ldr.2422) Prats et al., 2015

  14. A Miocene tectonic inversion in the Ionian Sea (Central Mediterranean): evidence from multi-channel seismic data

    OpenAIRE

    Gallais, Flora; Gutscher, Marc Andre; Graindorge, David; Chamot Rooke, Nicolas; Klaeschen, Dirk

    2011-01-01

    It is widely accepted that the Central and Eastern Mediterranean are remnants of the Neo-Tethys. However, the orientation and timing of spreading of this domain remain controversial. Here, we present time migrated and pre-stack depth migrated NW-SE oriented Archimede (1997) lines together with the PrisMed01 (1993) profile to constrain the evolution of the Ionian basin. Our interpretation allows us to identify a large-scale set of SW-NE striking reverse faults beneath the Ionian Abyssal Plain....

  15. A New Model for the Seismogenic Behavior of Subducted Seamounts Based on Multi-Channel Seismic Reflection and GPS Data Collected in Central Ecuador.

    Science.gov (United States)

    Collot, J. Y.; Sanclemente, E.; Ribodetti, A.; Chlieh, M.; Jarrin, P.; Nocquet, J. M.

    2014-12-01

    The relationship between subducted seamounts and earthquakes has remained controversial. Although seamounts are expected to subduct aseismically, they have also been considered to generate large earthquakes. Based on a remarkable case study in Central Ecuador, we show that a subducted seamount can lock the shallow megathrust along its trailing flank preparing for a possible shallow (earthquake, while its leading flank keeps partially creeping along with frequent earthquake swarms and slow slip events (SSE). The erosive Ecuador convergent margin, which basement consists of high velocity (Vp=5 km/s) mafic rocks, is underthrust eastward at 4.7 cm/yr by the rugged Carnegie Ridge. As modeled by global positioning system (GPS) measurements acquired as close as 35 km from the trench axis at La Plata Island, the Central Ecuador margin figures a creeping subduction segment with the exception of a 50 km-diameter locked patch centered over the uplifted La Plata Island region. The 3D geometry of the plate-interface megathrust obtained from 2D-PreStack-Depth-Migration of a grid of multi-channel seismic reflection data collected near La Plata Island reveals a collection of closely spaced peaks that belong to a broad (55 X ~50 km) low-drag shape subducted seamount. The clear spatial correlation between the seamount and the highly coupled zone denotes the seamount as the main cause for both the locked patch and the island uplift. The absence of a seismically imaged subduction channel, the highly jagged seamount-trailing flank and the stiffness of the oceanic margin are found to be the principal long-term characteristics associated with shallow locking of the megathrust. Moreover, the combination of our structural interpretation and inter-seismic coupling map with 14-years of relocated seismicity, and the 2010 SSE and its associated microseismicity allow to propose a new model for the seismogenic behavior of subducting seamounts.

  16. Cloning and expression of ligand-gated ion-channel receptor L2 in central nervous system

    International Nuclear Information System (INIS)

    An orphan receptor of ligand-gated ion-channel type (L2, also termed ZAC according to the presence of zinc ion for channel activation) was identified by computer-assisted search programs on human genome database. The L2 protein shares partial homology with serotonin receptors 5HT3A and 5HT3B. We have cloned L2 cDNA derived from human caudate nucleus and characterized the exon-intron structure as follows: (1) The L2 protein has four transmembrane regions (M1-M4) and a long cytoplasmic loop between M3 and M4. (2) The sequence is conserved in species including chimpanzee, dog, cow, and opossum. (3) Nine exons form its protein-coding region and especially exon 5 corresponds to a disulfide bond region on the amino-terminal side. Our analysis using multiple tissue cDNA panels revealed that at least two splicing variants of L2 mRNA are present. The cDNA PCR amplification study revealed that L2 mRNA is expressed in tissues including brain, pancreas, liver, lung, heart, kidney, and skeletal muscle while 5HT3A mRNA could be detected in brain, heart, placenta, lung, kidney, pancreas, and skeletal muscle, and 5HT3B mRNA in brain, kidney, and skeletal muscle, suggesting different significance in tissue expression of these receptors. Regional expression of L2 mRNA and protein was examined in brain. The RT-PCR studies confirmed L2 mRNA expression in hippocampus, striatum, amygdala, and thalamus in adult brain. The L2 protein was immunolocalized by using antipeptide antibodies. Immunostained tissue sections revealed that L2-like immunoreactivity was dominantly expressed in the hippocampal CA3 pyramidal cells and in the polymorphic layer of the dentate gyrus. We analyzed the expression of L2 protein in HEK293 cells using GFP fusion protein reporter system. Western blots revealed that L2 protein confers sugar chains on the extracellular side. In transfected HEK293 cells, cellular membranes and intracellular puncta were densely labeled with GFP, suggesting selective dispatch to the

  17. Molecular physiology of pH-sensitive background K(2P) channels.

    Science.gov (United States)

    Lesage, Florian; Barhanin, Jacques

    2011-12-01

    Background K(2P) channels are tightly regulated by different stimuli including variations of external and internal pH. pH sensitivity relies on proton-sensing residues that influence channel gating and activity. Gene inactivation in the mouse is a revealing implication of K(2P) channels in many physiological functions ranging from hormone secretion to central respiratory adaptation. Surprisingly, only a few phenotypic traits of these mice have yet been directly related to the pH sensitivity of K(2P) channels. PMID:22170960

  18. Cyclic AMP-dependent protein kinase phosphorylates residues in the C-terminal domain of the cardiac L-type calcium channel alpha1 subunit.

    Science.gov (United States)

    Leach, R N; Brickley, K; Norman, R I

    1996-06-11

    The molecular basis of the regulation of cardiac L-type calcium channel activity by cAMP-dependent protein kinase (cA-PK) remains unclear. Direct cA-PK-dependent phosphorylation of the bovine ventricular alpha1 subunit in vitro has been demonstrated in microsomal membranes, detergent extracts and partially purified (+)-[3H]PN 200-110 receptor preparations. Two 32P-labeled phosphopeptides, derived from cyanogen bromide cleavage, of 4.7 and 9.5 kDa were immunoprecipitated specifically by site-directed antibodies against the rabbit cardiac alpha1 subunit amino acid sequences 1602-1616 and 1681-1694, respectively, consistent with phosphorylation at the cA-PK consensus sites at Ser(1627) and Ser(1700). No phosphopeptide products consistent with phosphorylation at three other C-terminal cA-PK consensus phosphorylation sites (Ser(1575), Ser(1848) and Ser(1928)) were identified using similar procedures suggesting that these sites are poor substrates for this kinase. Ser(1627) and Ser(1700) may represent sites of cA-PK phosphorylation involved in the physiological regulation of cardiac L-type calcium channel function. PMID:8664319

  19. Organochlorine pesticides residues and PCBs in benthic organisms of the inner shelf of the São Sebastião Channel, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Rosângela Gorni

    2004-06-01

    Full Text Available Thirty seven benthic samples of the inner shelf area of São Sebastião, Brazil, were collected between April 1994 and August 1998 and analysed for seventeen chlorinated pesticide residues and PCBs congeners. Pesticide residues and PCBs congeners levels were low (ng/g and predominantly found in the crustacean samples. DDE was the most frequently residue with a maximum of 9,7 ng/g followed by HCHs with maximum of 17,1ng/g. As for the PCBs, the heavier congeners predominate: CB 138,153,170, 180 and 183. Maximum total PCBs was 17,4 ug/g in a crab sample. Higher levels of PCBs are related to feeding habits and local inputs of raw sewage or land runoff. Although EPA and FDA (U.S.A below the guidelines for human consumption propose these levels, they do show that even in marine areas without intense agricultural or industrial activities these compounds are present at detectable levels.Trinta e sete amostras de bentos da área interna do Canal de São Sebastião, Brasil, foram coletadas entre Abril de 1994 e Agosto de 1998 e analisadas quanto aos níveis de resíduos de 17 pesticidas organoclorados os congêneres dos PCBs. Os níveis de resíduos de organoclorados e PCBs foram baixos( ng/g e encontrados com maior freqüência nas amostras de crustáceos. DDE foi o resíduo de pesticida encontrado com mais freqüência apresentado um máximo de 9,7 ng/g seguido dos isômeros de HCHs com um máximo de 17,1 ng/g. No caso dos PCBs os congêneres mais pesados foram os predominantes: CB 138, 153, 170, 180 e 183. O valor máximo de PCBs totais foi de 17,4 ug/g numa amostra de crustáceo. Níveis maiores de PCBs estão associados aos hábitos alimentares e introduções pontuais de esgotos e água de drenagem urbana. Apesar dos níveis observados estarem abaixo dos recomendados para consumo humano pela EPA e da FDA( U.S.A ,eles demonstram que mesmo em área marinhas costeiras sem agricultura intensiva ou atividades industriais de porte , estes compostos org

  20. Advantages and effects of nitrogen doping into the central channel of plasma in axially viewed-inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Addition of N2 to the nebulizer gas used in axially viewed-ICP OES is investigated. •A small flow of N2 (20 mL min−1) increases plasma robustness. •Addition of N2 through the nebulizer gas affects energy transfer in the ICP. •Matrix effects are mitigated by adding N2 and the ICP performance is maintained. -- Abstract: The effects and benefits of N2 addition to the central channel of the ICP through the nebulizer gas used in ICP OES with axial view configuration were investigated in the present study. The N2 flow rate, nebulizer gas flow rate, RF power and sample uptake rate were evaluated and compared for two sample introduction systems (pneumatic nebulization/aerosol desolvation and conventional pneumatic nebulization). It was observed that N2 did not affect solution nebulization and aerosol transport but affects the ICP characteristics. The higher thermal conductivity of N2 (in comparison with Ar) changes energy distribution in the ICP, observed by monitoring the signals of Ar emission lines and sodium emission. The ratio Mg(II)-280.270 nm/Mg(I)-285.213 nm was utilized as a diagnostic tool for plasma robustness. The addition of N2 (20 mL min−1) increased plasma robustness significantly and mitigated effects caused by Na, K and Ca. For 40 spectral lines evaluated, it was observed that the emission signals of ionic spectral lines were in general more affected by N2 than those of atomic spectral lines. Detection limits, precision, sensitivity and linearity of calibration curves obtained using N2-Ar-ICP were almost similar to those obtained using Ar-ICP. The analysis of 5 different reference materials revealed that accuracy was not degraded by adding N2 to the Ar-ICP

  1. Central Role of the Threonine Residue within the p+1 Loop of Receptor Tyrosine Kinase in STAT3 Constitutive Phosphorylation in Metastatic Cancer Cells

    OpenAIRE

    Yuan, Zheng-long; Guan, Ying-jie; Wang, Lijuan; Wei, Wenyi; Kane, Agnes B.; Chin, Y. Eugene

    2004-01-01

    The receptor tyrosine kinases (RTKs) RET, MET, and RON all carry the Metp+1loop→Thr point mutation (i.e., 2B mutation), leading to the formation of tumors with high metastatic potential. Utilizing a novel antibody array, we identified constitutive phosphorylation of STAT3 in cells expressing the 2B mutation but not wild-type RET. MET or RON with the 2B mutation also constitutively phosphorylated STAT3. Members of the EPH, the only group of wild-type RTK that carry Thrp+1loop residue, are ofte...

  2. Residuation theory

    CERN Document Server

    Blyth, T S; Sneddon, I N; Stark, M

    1972-01-01

    Residuation Theory aims to contribute to literature in the field of ordered algebraic structures, especially on the subject of residual mappings. The book is divided into three chapters. Chapter 1 focuses on ordered sets; directed sets; semilattices; lattices; and complete lattices. Chapter 2 tackles Baer rings; Baer semigroups; Foulis semigroups; residual mappings; the notion of involution; and Boolean algebras. Chapter 3 covers residuated groupoids and semigroups; group homomorphic and isotone homomorphic Boolean images of ordered semigroups; Dubreil-Jacotin and Brouwer semigroups; and loli

  3. Mutations in the K+ channel signature sequence.

    OpenAIRE

    Heginbotham, L; Lu, Z; Abramson, T; MacKinnon, R

    1994-01-01

    Potassium channels share a highly conserved stretch of eight amino acids, a K+ channel signature sequence. The conserved sequence falls within the previously defined P-region of voltage-activated K+ channels. In this study we investigate the effect of mutations in the signature sequence of the Shaker channel on K+ selectivity determined under bi-ionic conditions. Nonconservative substitutions of two threonine residues and the tyrosine residue leave selectivity intact. In contrast, mutations a...

  4. Crystal structure of the CaV2 IQ domain in complex with Ca2+/calmodulin: High-resolution mechanistic implications for channel regulation by Ca2+

    OpenAIRE

    Mori, Masayuki X.; Vander Kooi, Craig W.; Leahy, Daniel J.; Yue, David T.

    2008-01-01

    Calmodulin (CaM) regulation of Ca2+ channels is central to Ca2+ signaling. CaV1 versus CaV2 classes of these channels exhibit divergent forms of regulation, potentially relating to customized CaM/IQ interactions among different channels. Here, we report the crystal structures for the Ca2+/CaM—IQ domains of both CaV2.1 and CaV2.3 channels. These highly similar structures emphasize that major CaM contacts with the IQ domain extend well upstream of traditional consensus residues. Surprisingly, u...

  5. 集中式信道分配算法在WSN移动节点中的应用研究%Study on Centralized Channel Assignment Algorithm for Mobile Nodes in Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    赵军; 陈祥光; 刘春涛; 余向明; 岳彬

    2011-01-01

    为提高油料保障系统中信息采集的实时性和能量的高效性,使网关及时检测到移动设备的状态,降低无线网络间的干扰,提高网络的容量.以军用机场加油车为研究对象,提出了适用于快速移动节点的集中式信道分配算法和功率分级的能量控制方法.在无线网络节点上安装两个工作在不同频道上的网络接口,通过控制协商动态的切换数据信道,平衡网络负载,以增加总的带宽.实验结果表明,采用3条数据信道便可实现信道的集中式分配和发送功率的分级控制,有效地扩展了网络的容量和提高能量的高效性.%By investigating the working process of tanker trucks in a military airport, this paper proposes a centralized channel assignment algorithm and a power rating control method for fast-moving nodes to improve the real-time property and energy efficiency of the information collection, detect the state of mobile devices promptly, reduce interference between wireless networks and to increase network capacity in oil security systems. Considering the fact that IEEE 802. 11 wireless LAN standard defines a number of non-overlapping channels which could be used at the same time, two wireless network interfaces operating on different channels could be installed to every node. Through the negotiation on the control channel and switching the data channel dynamically, the balance of network loads could be fulfilled so as to increase the total bandwidth. Simulation and application results demonstrate that, only three data channels is needed to realize the centralized channel assignment and the power rating control, and the network capacity and energy efficiency could be improved effectively.

  6. Assessment of the effect of insecticide-treated nets and indoor residual spraying for malaria control in three rural kebeles of Adami Tulu District, South Central Ethiopia

    Directory of Open Access Journals (Sweden)

    Bekele Damtew

    2012-04-01

    Full Text Available Abstract Background In the Adami Tulu District, indoor residual spraying (IRS and insecticide-treated nets (ITNs has been the main tool used to control malaria. The purpose of this study was to assess the effect of IRS and ITNs control strategies in Aneno Shisho kebele (lowest administrative unit of Ethiopia compared with Kamo Gerbi (supplied ITN only and Jela Aluto (no IRS and ITNs, with regards to the prevalence of malaria and mosquito density. Methods Cross-sectional surveys were conducted after heavy rains (October/November, 2006 and during the sporadic rains (April, 2007 in the three kebeles of Adami Tulu District. Malaria infection was measured by means of thick and thin film. Monthly collection of adult mosquitoes from October-December 2006 and April-May 2007 and sporozoite enzyme-linked immunosorbent assay (ELISA on the collected mosquitoes were detected. Data related to the knowledge of mode of malaria transmission and its control measures were collected. Data collected on parasitological and knowledge, attitude and practice (KAP surveys were managed and analysed using a statistical computer program SPSS version 13.0. A P-value Results The overall prevalence of malaria was 8.6% in Jela Aluto, 4.4% in Kamo Gerbi and 1.3% in Aneno Shisho in the two season surveys. The vector, Anopheles gambiae s.l., Anopheles pharoensis and Anopheles coustani were recorded. However, sporozoite ELISA on mosquito collections detected no infection. The difference in overall malaria prevalence and mosquito density between the three kebeles was significant (P Conclusions The present study has provided some evidence for the success of ITNs/IRS combined malaria control measures in Aneno Shisho kebele in Adami Tulu District. Therefore, the combined ITNs/IRS malaria control measures must be expanded to cover all kebeles in the District of Ethiopia.

  7. Protein Kinase A Is Central for Forward Transport of Two-pore Domain Potassium Channels K2P3.1 and K2P9.1*

    OpenAIRE

    Mant, Alexandra; Elliott, David; Eyers, Patrick A.; O'Kelly, Ita M.

    2011-01-01

    Acid-sensitive two-pore domain potassium channels (K2P3.1 and K2P9.1) play key roles in both physiological and pathophysiological mechanisms, the most fundamental of which is control of resting membrane potential of cells in which they are expressed. These background “leak” channels are constitutively active once expressed at the plasma membrane, and hence tight control of their targeting and surface expression is fundamental to the regulation of K+ flux and cell excitability. The chaperone p...

  8. Central functions of bicarbonate in S-type anion channel activation and OST1 protein kinase in CO 2 signal transduction in guard cell

    KAUST Repository

    Xue, Shaowu

    2011-03-18

    Plants respond to elevated CO(2) via carbonic anhydrases that mediate stomatal closing, but little is known about the early signalling mechanisms following the initial CO(2) response. It remains unclear whether CO(2), HCO(3)(-) or a combination activates downstream signalling. Here, we demonstrate that bicarbonate functions as a small-molecule activator of SLAC1 anion channels in guard cells. Elevated intracellular [HCO(3)(-)](i) with low [CO(2)] and [H(+)] activated S-type anion currents, whereas low [HCO(3)(-)](i) at high [CO(2)] and [H(+)] did not. Bicarbonate enhanced the intracellular Ca(2+) sensitivity of S-type anion channel activation in wild-type and ht1-2 kinase mutant guard cells. ht1-2 mutant guard cells exhibited enhanced bicarbonate sensitivity of S-type anion channel activation. The OST1 protein kinase has been reported not to affect CO(2) signalling. Unexpectedly, OST1 loss-of-function alleles showed strongly impaired CO(2)-induced stomatal closing and HCO(3)(-) activation of anion channels. Moreover, PYR/RCAR abscisic acid (ABA) receptor mutants slowed but did not abolish CO(2)/HCO(3)(-) signalling, redefining the convergence point of CO(2) and ABA signalling. A new working model of the sequence of CO(2) signalling events in gas exchange regulation is presented.

  9. Planimetric and volumetric analysis of channel change in the post-hydraulic mining period (1906-2009) in the Central Valley, California

    Science.gov (United States)

    Ghoshal, Subhajit

    Advances in remote sensing technologies can facilitate acquisition of topographical and planimetric information in fluvial environments and can produce spatial data with high spatial and temporal resolutions. Measuring planimetric and volumetric change in fluvial sediment budgets and geomorphic change detection was used for long-term monitoring of a fluvial system. Channel and floodplain changes caused by hydraulic gold mining sediment in this system are a major example of anthropogenic impacts on a fluvial system. This study uses remote sensing change-detection techniques to examine spatial and temporal patterns of HMS redistribution at a centennial time scale, and to measure and evaluate the magnitude and processes of a major channel and floodplain metamorphosis. Five reach-scale sites along the lower Yuba River and two sites on the Feather River were chosen for detailed analysis of planimetric and volumetric changes over a period of ~100 years. Volumetric changes were measured using DEM differencing and soft-copy photogrammetry methods, and planimetric changes were recorded from rectified maps and aerial photographs. This study indicates significant changes in channel morphology and sediment storage over the last 100 years. Large deposits of historical sediment remaining in the bed, banks and terraces of the lower Yuba River were remobilized by floods. The volumetric analysis shows the results of dredging of ditches, deposition in natural levees, and net erosion of high-water channels from 1906 or 1909 to 1999. Over the last century, channels incised up to ~13 m into mining sediment deposits. Systematic uncertainty analysis reveals vertical errors are mostly dependent on the topographical slopes and maximum errors are concentrated on the steep channel banks and scarps. The planimetric analysis shows significant reworking of sediment occurred throughout the 72-year period from 1937 to 2009. Substantial amounts of HMS remobilization occurred during major flood

  10. Channel Networks

    Science.gov (United States)

    Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio; Rigon, Riccardo

    This review proceeds from Luna Leopold's and Ronald Shreve's lasting accomplishments dealing with the study of random-walk and topologically random channel networks. According to the random perspective, which has had a profound influence on the interpretation of natural landforms, nature's resiliency in producing recurrent networks and landforms was interpreted to be the consequence of chance. In fact, central to models of topologically random networks is the assumption of equal likelihood of any tree-like configuration. However, a general framework of analysis exists that argues that all possible network configurations draining a fixed area are not necessarily equally likely. Rather, a probability P(s) is assigned to a particular spanning tree configuration, say s, which can be generally assumed to obey a Boltzmann distribution: P(s) % e^-H(s)/T, where T is a parameter and H(s) is a global property of the network configuration s related to energetic characters, i.e. its Hamiltonian. One extreme case is the random topology model where all trees are equally likely, i.e. the limit case for T6 4 . The other extreme case is T 6 0, and this corresponds to network configurations that tend to minimize their total energy dissipation to improve their likelihood. Networks obtained in this manner are termed optimal channel networks (OCNs). Observational evidence suggests that the characters of real river networks are reproduced extremely well by OCNs. Scaling properties of energy and entropy of OCNs suggest that large network development is likely to effectively occur at zero temperature (i.e. minimizing its Hamiltonian). We suggest a corollary of dynamic accessibility of a network configuration and speculate towards a thermodynamics of critical self-organization. We thus conclude that both chance and necessity are equally important ingredients for the dynamic origin of channel networks---and perhaps of the geometry of nature.

  11. Curative treatment for central nervous system medulloepithelioma despite residual disease after resection. Report of two cases treated according to the GPHO protocol HIT 2000 and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Klaus [Leipzig Univ. (Germany). Dept. of Radiotherapy and Radiooncology; Zwiener, Isabella [University Medical Center Univ. Mainz (Germany). Inst. for Medical Biostatistics, Epidemiology and Informatics; Welker, Helmut [Katharinenhospital, Stuttgart (Germany). Dept. of Radiotherapy and Radiooncology; Maass, Eberhard [Klinikum Stuttgart - Olgahospital (DE). Pediatrics 5 (Oncology, Hematology, Immunology); Bongartz, Rudolf [Koeln Univ. (Germany). Dept. of Radiotherapy and Radiooncology; Berthold, Frank [Koeln Univ. (Germany). Dept. of Pediatric Oncology; Pietsch, Torsten [Bonn Univ. Medical Center (Germany). Dept. of Neuropathology; Warmuth-Metz, Monika [Wuerzburg Univ. (Germany). Dept. of Neuroradiology; Bueren, Andre von; Rutkowski, Stefan [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Pediatric Hematology and Oncology

    2011-11-15

    Medulloepithelioma of the central nervous system (CNS) is an uncommon primitive neuroectodermal tumor (PNET) usually occurring in early childhood. It is characterized by highly malignant behavior with a propensity for progression, recurrence, and dissemination despite intensive therapy. Due to its rarity, the optimal management is still unknown. However, gross total resection (GTR) has been considered crucial to achieve cure. In this article, the authors report on 2 cases of CNS medulloepithelioma in which long-term survival (more than 6 years) could be achieved despite evidence of, or suspected postoperative residual disease with an otherwise dismal prognosis. The patients were treated according to different strata of the protocol for primitive neuroectodermal tumors (PNET) of the German-Austrian multicenter trial of the German Society for Pediatric Oncology and Hematology (GPOH) for childhood brain tumors (HIT 2000). Treatment included postoperative hyperfractionated radiotherapy of the craniospinal axis followed by a boost to the tumor site in combination with chemotherapy. A review of the 2 reported and 37 previously published cases confirmed GTR and older age as positive prognostic factors. (orig.)

  12. RFI channels

    Science.gov (United States)

    Mceliece, R. J.

    1980-01-01

    A class of channel models is presented which exhibit varying burst error severity much like channels encountered in practice. An information-theoretic analysis of these channel models is made, and conclusions are drawn that may aid in the design of coded communication systems for realistic noisy channels.

  13. A Common Structural Component for β-Subunit Mediated Modulation of Slow Inactivation in Different KV Channels

    DEFF Research Database (Denmark)

    Strutz-Seebohm, Nathalie; Henrion, Ulrike; Schmitt, Nicole;

    2013-01-01

    inactivation by structurally dissimilar β-subunits in different KV channels. Conclusion: We propose a model in which structural changes accompanying activation and β-subunit modulation allosterically constrain the backbone carbonyl oxygen atoms via the side chain of the respective X-residue in the signature......Background/Aims: Potassium channels are tetrameric proteins providing potassium selective passage through lipid embedded proteinaceous pores with highest fidelity. The selectivity results from binding to discrete potassium binding sites and stabilization of a hydrated potassium ion in a central...... internal cavity. The four potassium binding sites, generated by the conserved TTxGYGD signature sequence are formed by the backbone carbonyls of the amino acids TXGYG. Residues KV1.5-Val481, KV4.3-Leu368 and KV7.1- Ile 313 represent the amino acids in the X position of the respective channels. Methods...

  14. Zircons traced from the 700-500 Ma Transgondwanan Supermountains and the Gamburtsev Subglacial Mountains to the Ordovician Lachlan Orogen, Cretaceous Ceduna Delta, and modern Channel Country, central-southern Australia

    Science.gov (United States)

    Veevers, J. J.; Belousova, E. A.; Saeed, A.

    2016-04-01

    We test the hypothesis that the Transgondwanan Supermountains at the collision of East and West Gondwanaland were the provenance of a vast turbiditic fan that stretched alongside the East Gondwanaland margin to eastern Australia which, in turn, became the provenance of sediment shed into interior Australia to the Cretaceous Ceduna Delta in central-southern Australia and the modern Channel Country of central Australia. We employ an integrated analysis (U-Pb, Lu-Hf isotopes and trace elements) of detrital zircons in the Ceduna Delta and Channel Country. The main properties of the detrital zircons are U-Pb ages of 700-500 Ma (model ages TDMC 2.5-1.0 Ga; εHf +10 to -20) and 1300-1000 Ma ages (TDMC 2.7-1.3 Ga; εHf +4 to -17), in hosts of mafic granitoids with alkaline affinity. Zircons with these properties can be traced back through the drainage/paleo-slope to the intermediate provenances of the Ordovician turbidites and S-type granitoids of the Lachlan Orogen, then up-paleoslope to the primary or secondary provenance of the ancestral Gamburtsev Subglacial Mountains, and finally to the primary provenance of the Transgondwanan Supermountains atop the 700-500 Ma East African-Antarctic Orogen. Another primary provenance, the 140-95 Ma Whitsunday Volcanic Province/New Caledonia arc in northeastern Australia, also shed sediment across Australia to the Ceduna Delta. We suggest that the primary sediment from the 700-500 Ma East African-Antarctic Orogen and the ancestral Gamburtsev Subglacial Mountains was shed into a deep-sea super-fan to (1) Ordovician turbidites in southeast Australia, recycled by melting of the turbidites to (2) 450 Ma S-type granites in the Lachlan Orogen, and (3) finally deposited, together with volcanogenic sediment from northeast Australia, in the Ceduna Delta. Zircons in the Channel Country and the Ceduna Delta have essentially the same properties, and indicate that the northeastern Australian provenance was largely unchanged over the past 100 Ma.

  15. U.S. Isostatic Residual Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — isores.bin - standard grid containing isostatic residual gravity map for U.S. Grid interval = 4 km. Projection is Albers (central meridian = 96 degrees West; base...

  16. Distribution of Voltage-Gated Sodium Channel (Nav) Alleles among the Aedes aegypti Populations In Central Java Province and Its Association with Resistance to Pyrethroid Insecticides

    Science.gov (United States)

    Sayono, Sayono; Hidayati, Anggie Puspa Nur; Fahri, Sukmal; Sumanto, Didik; Dharmana, Edi; Hadisaputro, Suharyo; Asih, Puji Budi Setia; Syafruddin, Din

    2016-01-01

    The emergence of insecticide resistant Aedes aegypti mosquitoes has hampered dengue control efforts. WHO susceptibility tests, using several pyrethroid compounds, were conducted on Ae. aegypti larvae that were collected and raised to adulthood from Semarang, Surakarta, Kudus and Jepara in Java. The AaNaV gene fragment encompassing kdr polymorphic sites from both susceptible and resistant mosquitoes was amplified, and polymorphisms were associated with the resistant phenotype. The insecticide susceptibility tests demonstrated Ae, aegypti resistance to the pyrethroids, with mortality rates ranging from 1.6%–15.2%. Three non-synonymous polymorphisms (S989P, V1016G and F1534C) and one synonymous polymorphism (codon 982) were detected in the AaNaV gene. Eight AaNaV alleles were observed in specimens from Central Java. Allele 3 (SGF) and allele 7 (PGF) represent the most common alleles found and demonstrated strong associations with resistance to pyrethroids (OR = 2.75, CI: 0.97–7.8 and OR = 7.37, CI: 2.4–22.5, respectively). This is the first report of 8 Ae. aegypti AaNaV alleles, and it indicates the development of resistance in Ae. aegypti in response to pyrethroid insecticide-based selective pressure. These findings strongly suggest the need for an appropriate integrated use of insecticides in the region. The 989P, 1016G and 1534C polymorphisms in the AaNaV gene are potentially valuable molecular markers for pyrethroid insecticide resistance monitoring. PMID:26939002

  17. Congruent pattern of accessibility identifies minimal pore gate in a non-symmetric voltage-gated sodium channel.

    Science.gov (United States)

    Oelstrom, Kevin; Chanda, Baron

    2016-01-01

    Opening and closing of the central ion-conducting pore in voltage-dependent ion channels is gated by changes in membrane potential. Although a gate residue in the eukaryotic voltage-gated sodium channel has been identified, the minimal molecular determinants of this gate region remain unknown. Here, by measuring the closed- and open-state reactivity of MTSET to substituted cysteines in all the pore-lining helices, we show that the state-dependent accessibility is delineated by four hydrophobic residues at homologous positions in each domain. Introduced cysteines above these sites do not react with intracellular MTSET while the channels are closed and yet are rapidly modified while the channels are open. These findings, in conjunction with state-dependent metal cross-bridging, support the notion that the gate residues in each of the four S6 segments of the eukaryotic sodium channel form an occlusion for ions in the closed state and are splayed open on activation. PMID:27186888

  18. The structure of GlpF, a glycerol conducting channel.

    Science.gov (United States)

    Fu, Dax; Libson, Andrew; Stroud, Robert

    2002-01-01

    The passage of water or small neutral solutes across the cell membrane in animals, plants and bacteria is facilitated by a family of homologous membrane channels, variously known as aquaporins though perhaps more correctly as aquaglyceroporins. The glycerol facilitator (GlpF) is a 28 kDa aquaglyceroporin that catalyses transmembrane diffusion of glycerol and certain linear polyhydric alcohols in Escherichia coli. X-ray crystallographic analysis of GlpF to 2.2 A resolution revealed an alpha-barrel structure, surrounded by six full-length transmembrane helices and two half-spanning helices that are joined head-to-head in the middle of the membrane. These helices are arranged to a quasi twofold manner relative to the central membrane plane, where highly conserved residues make helix-to-helix contacts that stabilize the relative position and orientation of the helices in the structure. This sequence-structure correlation suggests that the evolutionary divergence of aquaporins and aquaglyceroporins is constrained by a conserved structural framework within which specialized function may be developed. Three glycerol molecules were resolved in the central channel through the GlpF monomer, thereby defining a transmembrane channel for glycerol permeation. The structure of glycerol GlpF complex provides insight into the chemical basis for transmembrane selective permeability. PMID:12027015

  19. Ion Channels, Natural Nanovalves

    OpenAIRE

    Eisenberg, Bob

    2012-01-01

    Ion channels are proteins with holes down their middle that control the flow of ions and electric current across otherwise impermeable biological membranes. The flow of sodium, potassium, calcium (divalent), and chloride ions have been central issues in biology for more than a century. The flow of current is responsible for the signals of the nervous system that propagate over long distances (meters). The concentration of divalent calcium ions is a 'universal' signal that controls many differ...

  20. Photon Channelling in Foams

    OpenAIRE

    Schmiedeberg, Michael; Miri, MirFaez; Stark, Holger

    2005-01-01

    Experiments by Gittings, Bandyopadhyay, and Durian [Europhys. Lett.\\ \\textbf{65}, 414 (2004)] demonstrate that light possesses a higher probability to propagate in the liquid phase of a foam due to total reflection. The authors term this observation photon channelling which we investigate in this article theoretically. We first derive a central relation in the work of Gitting {\\em et al.} without any free parameters. It links the photon's path-length fraction $f$ in the liquid phase to the li...

  1. Resíduos de agrotóxicos na água de rios da Depressão Central do Estado do Rio Grande do Sul, Brasil Residues of pesticides in the water of the Depression Central rivers in the State of Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Enio Marchesan

    2010-05-01

    Full Text Available A atividade orizícola é conduzida com uso intensivo de agrotóxicos, os quais, dependendo do manejo e das precipitações pluviais, podem chegar até os rios. O objetivo do trabalho foi determinar resíduos dos herbicidas clomazona, quincloraque, propanil, bentazona, 2,4-D e imazethapyr e dos inseticidas carbofurano e fipronil nos rios Vacacaí e Vacacaí-Mirim, situados na Depressão Central do Rio Grande do Sul, nas safras de 2003/04 a 2007/08, com coletas realizadas de novembro a fevereiro (cultivo do arroz. As análises dos herbicidas e do carbofurano foram realizadas por HPLC-DAD, e a análise do fipronil foi realizada por GC-ECD. Na safra 2003/04, em ambos os rios, os herbicidas clomazona, 2,4-D e propanil foram os mais frequentes nas amostras de água. Na safra 2004/05, o quincloraque foi detectado em maior número de amostras, já nas safras 2005/06 e 2006/07 fipronil foi o agrotóxico mais frequente nas amostras nos rios Vacacaí e Vacacaí-Mirim. Na safra de 2007/08, houve menor presença de resíduos de agrotóxicos nos rios Vacacaí e Vacacaí-Mirim. Há presença de agrotóxicos utilizados na lavoura de arroz nos rios Vacacaí e Vacacaí-Mirim durante o período de cultivo de arroz irrigado, destacando-se, entre os analisados, os herbicidas clomazona e quincloraque e o inseticida fipronil.The rice-growing activity is conducted out with intensive use of agrochemicals, which, depending on the management and rainfall can reach rivers. The study aimed to determine the residues of herbicides clomazone, quinclorac, propanil, bentazone, 2,4-D and imazethapyr and insecticides carbofuran and fipronil in the Vacacaí and Vacacaí-Mirim rivers, located in the Central Depression of Rio Grande do Sul, in the crop of 2003/04 untill 2007/08. Samples were collected from November to February (rice growing season. Analysis of herbicides and carbofuran were performed by HPLC-DAD and fipronil by GC-ECD. During 2003/04, in both rivers, the herbicide

  2. Role of the membrane for mechanosensing by tethered channels

    CERN Document Server

    Sabass, Benedikt

    2016-01-01

    Biologically important membrane channels are gated by force at attached tethers. Here, we generically characterize the non-trivial interplay of force, membrane tension, and channel deformations that can affect gating. A central finding is that minute conical channel deformation under force leads to significant energy release during opening. We also calculate channel-channel interactions and show that they can amplify force sensitivity of tethered channels.

  3. The effects of huwentoxin-I on the voltage-gated sodium channels of rat hippocampal and cockroach dorsal unpaired median neurons.

    Science.gov (United States)

    Wang, Meichi; Rong, Mingqiang; Xiao, Yucheng; Liang, Songping

    2012-03-01

    Huwentoxin-I (HWTX-I) is a 33-residue peptide isolated from the venom of Ornithoctonus huwena and could inhibit TTX-sensitive voltage-gated sodium channels and N-type calcium channels in mammalian dorsal root ganglion (DRG) neurons. However, the effects of HWTX-I on mammalian central neuronal and insect sodium channel subtypes remain unknown. In this study, we found that HWTX-I potently inhibited sodium channels in rat hippocampal and cockroach dorsal unpaired median (DUM) neurons with the IC(50) values of 66.1±5.2 and 4.80±0.58nM, respectively. Taken together with our previous work on DRG neurons (IC(50)≈55nM), the order of sodium channel sensitivity to HWTX-I inhibition was insect central DUM≫mammalian peripheral>mammalian central neurons. HWTX-I exhibited no effect on the steady-state activation and inactivation of sodium channels in rat hippocampal and cockroach DUM neurons. PMID:22094230

  4. Post-Translational Modifications of TRP Channels

    Directory of Open Access Journals (Sweden)

    Olaf Voolstra

    2014-04-01

    Full Text Available Transient receptor potential (TRP channels constitute an ancient family of cation channels that have been found in many eukaryotic organisms from yeast to human. TRP channels exert a multitude of physiological functions ranging from Ca2+ homeostasis in the kidney to pain reception and vision. These channels are activated by a wide range of stimuli and undergo covalent post-translational modifications that affect and modulate their subcellular targeting, their biophysical properties, or channel gating. These modifications include N-linked glycosylation, protein phosphorylation, and covalent attachment of chemicals that reversibly bind to specific cysteine residues. The latter modification represents an unusual activation mechanism of ligand-gated ion channels that is in contrast to the lock-and-key paradigm of receptor activation by its agonists. In this review, we summarize the post-translational modifications identified on TRP channels and, when available, explain their physiological role.

  5. Vesícula residual Residual gallbladder

    Directory of Open Access Journals (Sweden)

    Júlio C. U. Coelho

    2002-12-01

    Full Text Available Our objective is to report three patients with recurrent severe upper abdominal pain secondary to residual gallbladder. All patients had been subjected to cholecystectomy from 1 to 20 years before. The diagnosis was established after several episodes of severe upper abdominal pain by imaging exams: ultrasonography, tomography, or endoscopic retrograde cholangiography. Removal of the residual gallbladder led to complete resolution of symptoms. Partial removal of the gallbladder is a very rare cause of postcholecystectomy symptoms.

  6. Voltage-gated proton channels.

    Science.gov (United States)

    Decoursey, Thomas E

    2012-04-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely, the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn(2+) (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B-lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H(+) for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID

  7. Importance of Indole N-H Hydrogen Bonding in the Organization and Dynamics of Gramicidin Channels

    OpenAIRE

    Chaudhuri, Arunima; Haldar, Sourav; Sun, Haiyan; Koeppe, Roger E.; Chattopadhyay, Amitabha

    2013-01-01

    The linear ion channel peptide gramicidin represents an excellent model for exploring the principles underlying membrane protein structure and function, especially with respect to tryptophan residues. The tryptophan residues in gramicidin channels are crucial for the structure and function of the channel. In order to test the importance of indole hydrogen bonding for the biophysical properties of gramicidin channels, we monitored the effect of N-methylation of gramicidin tryptophans, using a ...

  8. A Common Structural Component for β-Subunit Mediated Modulation of Slow Inactivation in Different KV Channels

    Directory of Open Access Journals (Sweden)

    Nathalie Strutz-Seebohm

    2013-06-01

    Full Text Available Background/Aims: Potassium channels are tetrameric proteins providing potassium selective passage through lipid embedded proteinaceous pores with highest fidelity. The selectivity results from binding to discrete potassium binding sites and stabilization of a hydrated potassium ion in a central internal cavity. The four potassium binding sites, generated by the conserved TTxGYGD signature sequence are formed by the backbone carbonyls of the amino acids TXGYG. Residues KV1.5-Val481, KV4.3-Leu368 and KV7.1- Ile 313 represent the amino acids in the X position of the respective channels. Methods: Here, we study the impact of these residues on ion selectivity, permeation and inactivation kinetics as well as the modulation by β-subunits using site-specific mutagenesis, electrophysiological analyses and molecular dynamics simulations. Results: We identify this position as key in modulation of slow inactivation by structurally dissimilar β-subunits in different KV channels. Conclusion: We propose a model in which structural changes accompanying activation and β-subunit modulation allosterically constrain the backbone carbonyl oxygen atoms via the side chain of the respective X-residue in the signature sequence to reduce conductance during slow inactivation.

  9. Residual foreground contamination in the WMAP data

    International Nuclear Information System (INIS)

    We have studied whether there is any residual foreground contamination in the foreground reduced WMAP-7 data for the differential assemblies (DAs) Q, V and W. We have calculated the correlation between the foreground map, from which long wavelength correlations have been subtracted, and the foreground reduced map for each DA. We have found positive correlations for all the channels. The statistical significance of the resulting values has been tested by comparing with correlations between the cleaned CMB maps and 1000 simulated Gaussian maps to which instrumental effects have been added. We have found high statistical significance of the observed correlations, implying the presence of residual contamination in the cleaned data, and found that, for Q and V channels, a large fraction of the contamination comes from pixels, where the foreground maps have positive values larger than three times its rms value, which shows the presence of unresolved point sources that contribute significantly to the contamination

  10. Alternative translation initiation in rat brain yields K2P2.1 potassium channels permeable to sodium

    OpenAIRE

    Thomas, Dierk; Plant, Leigh D.; Wilkens, Christina M.; McCrossan, Zoe A.; Goldstein, Steve A. N.

    2008-01-01

    K2P channels mediate potassium background currents essential to central nervous system function, controlling excitability by stabilizing membrane potential below firing threshold and expediting repolarization. Here, we show that alternative translation initiation (ATI) regulates function of K2P2.1 (TREK-1) via a novel strategy. Full length K2P2.1 and an isoform lacking the first 56 residues of the intracellular N-terminus (K2P2.1 Δ1-56) are produced differentially in a regional and developmen...

  11. The role of the central L- or D-Pro residue on structure and mode of action of a cell-selective alpha-helical IsCT-derived antimicrobial peptide.

    Science.gov (United States)

    Lim, Shin Saeng; Kim, Yangmee; Park, Yoonkyung; Kim, Jae Il; Park, Il-Seon; Hahm, Kyung-Soo; Shin, Song Yub

    2005-09-01

    IsCT-P (ILKKIWKPIKKLF-NH2) is a novel alpha-helical antimicrobial peptide with bacterial cell selectivity designed from a scorpion-derived peptide IsCT. To investigate the role of L- or D-Pro kink on the structure and the mode of action of a short alpha-helical antimicrobial peptide with bacterial cell selectivity, we synthesized IsCT-p, in which D-Pro is substituted for L-Pro8 of IsCT-P. CD spectra revealed that IsCT-P adopted a typical alpha-helical structure in various membrane-mimicking conditions, whereas IsCT-p showed a random structure. This result indicated that D-Pro in the central position of a short alpha-helical peptide provides more remarkable structural flexibility than L-Pro. Despite its higher antibacterial activity, IsCT-p was much less effective at inducing dye leakage in the negatively charged liposome mimicking bacterial membrane and induced no or little membrane potential depolarization of Staphylococcus aureus. Confocal laser scanning microscopy showed that IsCT-p penetrated the bacterial cell membrane and accumulated in the cytoplasm, whereas IsCT-P remained outside or on the cell membrane. These results suggested that the major target of IsCT-P and IsCT-p is the bacterial membranes and intracellular components, respectively. Collectively, our results demonstrated that the central D-Pro kink in alpha-helical antimicrobial peptides plays an important role in penetrating bacterial membrane as well as bacterial cell selectivity. PMID:16040002

  12. The Channels of Monetary Transmission: Lessons for Monetary Policy

    OpenAIRE

    Mishkin, Frederic S.

    1996-01-01

    This paper provides an overview of the transmission mechanisms of monetary policy, starting with traditional interest rate channels, going on to channels operating through other asset prices, and then on to the so-called credit channels. The paper then discusses the implications from this literature for how central banks might best conduct monetary policy.

  13. Evidence for Central Regulation of Glucose Metabolism*

    OpenAIRE

    Carey, Michelle; Kehlenbrink, Sylvia; Hawkins, Meredith

    2013-01-01

    Evidence for central regulation of glucose homeostasis is accumulating from both animal and human studies. Central nutrient and hormone sensing in the hypothalamus appears to coordinate regulation of whole body metabolism. Central signals activate ATP-sensitive potassium (KATP) channels, thereby down-regulating glucose production, likely through vagal efferent signals. Recent human studies are consistent with this hypothesis. The contributions of direct and central inputs to metabolic regulat...

  14. Channeling experiment

    International Nuclear Information System (INIS)

    Channeling of water flow and tracer transport in real fractures in a granite body at Stripa have been investigated experimentally. The experimental site was located 360 m below the ground level. Two kinds of experiments were performed. In the single hole experiments, 20 cm diameter holes were drilled about 2.5 m into the rock in the plane of the fracture. Specially designed packers were used to inject water into the fracture in 5 cm intervals all along the fracture trace in the hole. The variation of the injection flowrates along the fracture were used to determine the transmissivity variations in the fracture plane. Detailed photographs were taken from inside the hole and the visual fracture aperture was compared with the injection flowrates in the same locations. Geostatistical methods were used to evaluate the results. Five holes were measured in great detail. In addition 7 holes were drilled and scanned by simpler packer systems. A double hole experiment was performed where two parallel holes were drilled in the same fracture plane at nearly 2 m distance. Pressure pulse tests were made between the holes in both directions. Tracers were injected in 5 locations in one hole and monitored for in many locations in the other hole. The single hole experiment and the double hole experiment show that most of the fracture planes are tight but that there are open sections which form connected channels over distances of at least 2 meters. It was also found in the double hole experiment that the investigated fracture was intersected by at least one fracture between the two holes which diverted a large amount of the injected tracers to several distant locations at the tunnel wall. (authours)

  15. CENTRAL PLATEAU REMEDIATION

    Energy Technology Data Exchange (ETDEWEB)

    ROMINE, L.D.

    2006-02-01

    A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress.

  16. CENTRAL PLATEAU REMEDIATION

    International Nuclear Information System (INIS)

    A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress

  17. Methods of albedo electron densimetry. 2. Two-channel methods

    Energy Technology Data Exchange (ETDEWEB)

    Sorokin, V.B. (Tomskij Politekhnicheskij Inst. (USSR). Nauchno-Issledovatel' skij Inst. Ehlektronnoj Introskopii)

    1981-12-01

    Two-channel methods of densimetry permitting to realize control over density of materials with fluctuating composition which have been developed on the basis of one-channel albedo electron methods are considered. The two-channel methods permits to decrease the errors as compared with one-channel ones and when central-peripheral method is applied - also to increase the sensitivity to density variation. The methods are intended for control density of porous materials, especially in powder metallurgy, ceramics production, etc.

  18. Handling of Solid Residues

    International Nuclear Information System (INIS)

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  19. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  20. Thiometon residues in cucumber

    International Nuclear Information System (INIS)

    In the Islamic Republic of Iran, vegetables are treated repeatedly with pesticides to control pests and diseases. Crops harvested shortly after pesticide application are probably contaminated by pesticides that are toxic to humans. Pesticide residues in vegetables are especially important, since these crops are ingested directly by humans. In recent years, farmers have been using more persistent pesticides to protect their crops because of increasing pesticide prices. Field trials were carried out to determine the residues of thiometon, a systemic insecticide used on cucumber. In 1993 and 1994, Ekatin (a 25% thiometon emulsifiable concentrate) was applied with a knapsack sprayer to cucumber (var. Daminus) at late flowering at dilutions of 1:1000 and 2:1000. Plots were 25 m2 in three replicates and were sampled 3, 6, 10, 15, 19 and 24 days after application. The samples were extracted with acetonitrile and cleanup was carried out using thin layer chromatography. Thiometon and two metabolites (thiometon sulphide and thiometon sulphone) were analyzed by gas chromatography. In 1994, the amount of thiometon sulphide determined 24 days treatment was 2 ppm in the peeled cucumber, which exceeded the maximum residue limit of 0.5 ppm. The total thiometon residues were higher in the peeled cucumber than those in the cucumber peel. Thus, peeling is ineffective for reducing the systemic residues of thiometon. Likewise, in this experiment lower dilution caused higher rather than lower thiometon residues in cucumber. The rapid disappearance of thiometon residues 2 weeks after treatment suggests that storing cucumbers at room temperature may be a better strategy for reducing excessive thiometon residues. Alternatively, a contact insecticide could be used. Thus, the bulk of the surface residues could be removed by washing or peeling. (author). 5 refs, 4 figs

  1. FIR Filter Implementation Based on the RNS with Diminished-1 Encoded Channel

    Directory of Open Access Journals (Sweden)

    Dragana Uros Zivaljevic

    2013-03-01

    Full Text Available A technique, based on the residue number system (RNS with diminished-1 encoded channel, has being used for implementing a finite impulse response (FIR digital filter. The proposed RNS architecture of the filter consists of three main blocks: forward and reverse converter and arithmetic processor for each channel. Architecture for residue to binary (reverse convertor with diminished-1 encoded channel has been proposed. Besides, for all RNS channels, the systolic design is used for the efficient  realization of FIR filter. A numerical example illustrates the principles of diminished-1 residue arithmetic, signal processing, and decoding for FIR filters.

  2. Optimized Combination of Residue Hydrodesulfurization and Residue Fluid Catalytic Cracking

    Institute of Scientific and Technical Information of China (English)

    Chen Junwu

    2003-01-01

    @@1 Introduction Combination of residue hydrodesulfurization (HDS) and resi-due fluid catalytic cracking (RFCC) is a unique technologyfor processing high-sulfur residue. This paper discusses theoptimized combination of these two processes.

  3. Channel strategy adaptation

    OpenAIRE

    Rangan, V. Kasturi; Nueno, Jose L

    1999-01-01

    Using transaction cost theory, considerable research in marketing has focused on the conditions under which firms would use direct or vertically integrated versus indirect or arms length channels of distribution. Data from the field, however, indicate that channel configurations are more varied and complex, with multiple channels and composite channels being just as common as direct and indirect channels. In an attempt to explain this variety, this paper revisits the influence on channel stru...

  4. New technologies in the D0 central tracker upgrade

    International Nuclear Information System (INIS)

    The D0 collaboration has undertaken an aggressive upgrade of its central tracking system. The existing tracker will be completely removed and replaced by a two Tesla superconducting solenoidal magnet, an 837 000 channel silicon vertex system, and 80 000 channel scintillating fiber tracker, followed by a 7 680 channel central preshower detector and a 16 000 channel forward preshower detector. In this paper the author discusses all of the subsystems of the D0 central tracker upgrade, but will emphasize those aspects which involve new technology: radiation hard scintillating fiber, VLPC's and extruded scintillating strips

  5. Ion Selectivity Mechanism in a Bacterial Pentameric Ligand-Gated Ion Channel

    International Nuclear Information System (INIS)

    The proton-gated ion channel from Gloeobacter violaceus (GLIC) is a prokaryotic homolog of the eukaryotic nicotinic acetylcholine receptor that responds to the binding of neurotransmitter acetylcholine and mediates fast signal transmission. Recent emergence of a high-resolution crystal structure of GLIC captured in a potentially open state allowed detailed, atomic-level insight into ion conduction and selectivity mechanisms in these channels. Herein, we have examined the barriers to ion conduction and origins of ion selectivity in the GLIC channel by the construction of potential-of-mean-force profiles for sodium and chloride ions inside the transmembrane region. Our calculations reveal that the GLIC channel is open for a sodium ion to transport, but presents a 11 kcal/mol free energy barrier for a chloride ion. Our collective findings identify three distinct contributions to the observed preference for the permeant ions. First, there is a substantial contribution due to a ring of negatively charged glutamate residues (E-2 ) at the narrow intracellular end of the channel. The negative electrostatics of this region and the ability of the glutamate side chains to directly bind cations would strongly favor the passage of sodium ions while hindering translocation of chloride ions. Second, our results imply a significant hydrophobic contribution to selectivity linked to differences in the desolvation penalty for the sodium versus chloride ions in the central hydrophobic region of the pore. This hydrophobic contribution is evidenced by the large free energy barriers experienced by Cl in the middle of the pore for both GLIC and the E-2 A mutant. Finally, there is a distinct contribution arising from the overall negative electrostatics of the channel.

  6. Robust Monetary Policy with the Cost Channel

    OpenAIRE

    Peter Tillmann

    2007-01-01

    Recent research argues that model uncertainty leads the central bank to adjust interest rates stronger to exogenous disturbances than under certainty. This paper investigates whether the introduction of a cost channel of monetary transmission, whose presence is empirically supported, changes the impact of model uncertainty on interest rate setting. The basic model is simple enough to facilitate an analytical closed form solution. We find that the presence of the cost channel dampens the effec...

  7. Channel capacities via $p$-summing norms

    OpenAIRE

    Junge, Marius; Palazuelos Cabezón, Carlos

    2013-01-01

    In this paper we show how the metric theory of tensor products developed by Grothendieck perfectly fits in the study of channel capacities, a central topic in Shannon’s information theory. Furthermore, in the last years Shannon’s theory has been fully generalized to the quantum setting, and revealed qualitatively new phenomena in comparison. In this paper we consider the classical capacity of quantum channels with restricted assisted entanglement. These capacities include the classical capaci...

  8. Microprocessor based 32 channel PCM telemetry system

    Science.gov (United States)

    Murthy, N. N.

    1987-08-01

    The details of a 32 channel PCM telemetry system developed to acquire data from flight experiments conducted on Pushpak aircraft and to be conducted on LCRA aircraft are presented. The system is designed using Intel 8085A central processing unit with its associated peripherals like 8255, 8251 and 8155. The system can be programmed to handle up to 32 channels of analog data. The bit rate can also be varied up to 56 Kilobits/sec.

  9. Losses in Channels with Increased External Turbulence

    Science.gov (United States)

    Zaryankin, A. Y.; Soloveva, G. S.

    1986-01-01

    An approximate method for determining the effect of the level of turbulence on the aerodynamic characteristics of convergent and diffuser channels is examined. A momentum equation for the boundary layer is in the method, introducing external flow turbulence on the basis of experimental values of the coefficient of friction and the form factor. It is found that at significant levels of external turbulence, losses must be considered not only in the boundary layer but also in the central region of the channel.

  10. The central mechanism underlying hypertension: a review of the roles of sodium ions, epithelial sodium channels, the renin–angiotensin–aldosterone system, oxidative stress and endogenous digitalis in the brain

    OpenAIRE

    Takahashi, Hakuo; Yoshika, Masamichi; Komiyama, Yutaka; Nishimura, Masato

    2011-01-01

    The central nervous system has a key role in regulating the circulatory system by modulating the sympathetic and parasympathetic nervous systems, pituitary hormone release, and the baroreceptor reflex. Digoxin- and ouabain-like immunoreactive materials were found >20 years ago in the hypothalamic nuclei. These factors appeared to localize to the paraventricular and supraoptic nuclei and the nerve fibers at the circumventricular organs and supposed to affect electrolyte balance and blood press...

  11. Characterization of Hospital Residuals

    International Nuclear Information System (INIS)

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author)

  12. Intracellular segment between transmembrane helices S0 and S1 of BK channel α subunit contains two amphipathic helices connected by a flexible loop

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Pan [Hefei National Laboratory of Microscale Physical Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027 (China); High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); Li, Dong; Lai, Chaohua [Hefei National Laboratory of Microscale Physical Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027 (China); Zhang, Longhua, E-mail: zlhustc@ustc.edu.cn [Hefei National Laboratory of Microscale Physical Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027 (China); Tian, Changlin, E-mail: cltian@ustc.edu.cn [Hefei National Laboratory of Microscale Physical Sciences, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027 (China); High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China)

    2013-08-02

    Highlights: •The loop between S0 and S1 of BK channel was overexpressed and purified in DPC. •NMR studies indicated BK-IS1 contained two helices connected by a flexible loop. •Mg{sup 2+} titration of BK-IS1 indicated two possible binding sites of divalent ions. -- Abstract: The BK channel, a tetrameric potassium channel with very high conductance, has a central role in numerous physiological functions. The BK channel can be activated by intracellular Ca{sup 2+} and Mg{sup 2+}, as well as by membrane depolarization. Unlike other tetrameric potassium channels, the BK channel has seven transmembrane helices (S0–S6) including an extra helix S0. The intracellular segment between S0 and S1 (BK-IS1) is essential to BK channel functions and Asp99 in BK-IS1 is reported to be responsible for Mg{sup 2+} coordination. In this study, BK-IS1 (44–113) was over-expressed using a bacterial system and purified in the presence of detergent micelles for multidimensional heteronuclear nuclear magnetic resonance (NMR) structural studies. Backbone resonance assignment and secondary structure analysis showed that BK-IS1 contains two amphipathic helices connected by a 36-residue loop. Amide {sup 1}H–{sup 15}N heteronuclear NOE analysis indicated that the loop is very flexible, while the two amphipathic helices are possibly stabilized through interaction with the membrane. A solution NMR-based titration assay of BK-IS1 was performed with various concentrations of Mg{sup 2+}. Two residues (Thr45 and Leu46) with chemical shift changes were observed but no, or very minor, chemical shift difference was observed for Asp99, indicating a possible site for binding divalent ions or other modulation partners.

  13. 二连盆地中部古河道砂岩型铀矿成矿机理及找矿方向%Mineralization Mechanism and Exploration of Paleo channel Type Uranium Deposit in Central Erlian Basin

    Institute of Scientific and Technical Information of China (English)

    刘武生; 康世虎; 赵兴齐; 史清平; 张梓楠

    2015-01-01

    According to the geological analysis of Ba Sai Qi paleo channel type uranium deposit,it was suggest that paleo channel is favorable space,structural inversion was the main dynamic factor and oxidation be the requite condition for uranium metallization. In combination with research of uranium for-mation age,the mineralization mechanism of Bayanwula type,Saihangaobi type,Qiharigetu type was studied and three metallogenic modesl was set up with 4 categories and 1 1 subcategories in the following indicators:source of uranium (internal and external),paleo channel (size,distribution,micro sedimen-tary faces,hydrodynamic force,lithology),structure (basement structure,deposition break,inversion structure),epigenetic alteration (phreatic oxidation,unilateral interlayer oxidation,both sides of the in-terlayer oxidation,hydrocarbon diffusion). With these models,4 level I,4 level II and 3 level III pros-pecting areas was prognosticated for further exploration in the basin.%通过巴赛齐古河道砂岩型铀成矿带内矿床地质分析,指明古河道是铀成矿的有利空间,构造反转是铀成矿的主控因素,氧化蚀变是铀成矿的必要条件;结合铀成矿时代研究,厘定了巴彦乌拉式、赛汉高毕式、齐哈日格图式铀成矿机理,构建了3种铀成矿模式,总结了铀源(外源和内源)、古河道(古河道规模、分布、沉积微相、水动力、岩性)、构造(基底构造、沉积间断、反转构造)、后生蚀变(潜水氧化、单侧层间氧化、两侧层间氧化、油气渗出)等4大类14小类预测标志,圈定优选了4片Ⅰ级、4片Ⅱ级、3片Ⅲ级预测区。

  14. A ligand channel through the G protein coupled receptor opsin.

    Directory of Open Access Journals (Sweden)

    Peter W Hildebrand

    Full Text Available The G protein coupled receptor rhodopsin contains a pocket within its seven-transmembrane helix (TM structure, which bears the inactivating 11-cis-retinal bound by a protonated Schiff-base to Lys296 in TM7. Light-induced 11-cis-/all-trans-isomerization leads to the Schiff-base deprotonated active Meta II intermediate. With Meta II decay, the Schiff-base bond is hydrolyzed, all-trans-retinal is released from the pocket, and the apoprotein opsin reloaded with new 11-cis-retinal. The crystal structure of opsin in its active Ops* conformation provides the basis for computational modeling of retinal release and uptake. The ligand-free 7TM bundle of opsin opens into the hydrophobic membrane layer through openings A (between TM1 and 7, and B (between TM5 and 6, respectively. Using skeleton search and molecular docking, we find a continuous channel through the protein that connects these two openings and comprises in its central part the retinal binding pocket. The channel traverses the receptor over a distance of ca. 70 A and is between 11.6 and 3.2 A wide. Both openings are lined with aromatic residues, while the central part is highly polar. Four constrictions within the channel are so narrow that they must stretch to allow passage of the retinal beta-ionone-ring. Constrictions are at openings A and B, respectively, and at Trp265 and Lys296 within the retinal pocket. The lysine enforces a 90 degrees elbow-like kink in the channel which limits retinal passage. With a favorable Lys side chain conformation, 11-cis-retinal can take the turn, whereas passage of the all-trans isomer would require more global conformational changes. We discuss possible scenarios for the uptake of 11-cis- and release of all-trans-retinal. If the uptake gate of 11-cis-retinal is assigned to opening B, all-trans is likely to leave through the same gate. The unidirectional passage proposed previously requires uptake of 11-cis-retinal through A and release of photolyzed all

  15. Design and characterization of a highly selective peptide inhibitor of the small conductance calcium-activated K+ channel, SkCa2.

    Science.gov (United States)

    Shakkottai, V G; Regaya, I; Wulff, H; Fajloun, Z; Tomita, H; Fathallah, M; Cahalan, M D; Gargus, J J; Sabatier, J M; Chandy, K G

    2001-11-16

    Apamin-sensitive small conductance calcium-activated potassium channels (SKCa1-3) mediate the slow afterhyperpolarization in neurons, but the molecular identity of the channel has not been defined because of the lack of specific inhibitors. Here we describe the structure-based design of a selective inhibitor of SKCa2. Leiurotoxin I (Lei) and PO5, peptide toxins that share the RXCQ motif, potently blocked human SKCa2 and SKCa3 but not SKCa1, whereas maurotoxin, Pi1, Tskappa, and PO1 were ineffective. Lei blocked these channels more potently than PO5 because of the presence of Ala(1), Phe(2), and Met(7). By replacing Met(7) in the RXCQ motif of Lei with the shorter, unnatural, positively charged diaminobutanoic acid (Dab), we generated Lei-Dab(7), a selective SKCa2 inhibitor (K(d) = 3.8 nm) that interacts with residues in the external vestibule of the channel. SKCa3 was rendered sensitive to Lei-Dab(7) by replacing His(521) with the corresponding SKCa2 residue (Asn(367)). Intracerebroventricular injection of Lei-Dab(7) into mice resulted in no gross central nervous system toxicity at concentrations that specifically blocked SKCa2 homotetramers. Lei-Dab(7) will be a useful tool to investigate the functional role of SKCa2 in mammalian tissues. PMID:11527975

  16. Management of NORM Residues

    International Nuclear Information System (INIS)

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  17. Mobile radio channels

    CERN Document Server

    Pätzold, Matthias

    2011-01-01

    Providing a comprehensive overview of the modelling, analysis and simulation of mobile radio channels, this book gives a detailed understanding of fundamental issues and examines state-of-the-art techniques in mobile radio channel modelling. It analyses several mobile fading channels, including terrestrial and satellite flat-fading channels, various types of wideband channels and advanced MIMO channels, providing a fundamental understanding of the issues currently being investigated in the field. Important classes of narrowband, wideband, and space-time wireless channels are explored in deta

  18. Molecular Dynamics of Channelrhodopsin at the Early Stages of Channel Opening.

    Directory of Open Access Journals (Sweden)

    Mizuki Takemoto

    Full Text Available Channelrhodopsin (ChR is a light-gated cation channel that responds to blue light. Since ChR can be readily expressed in specific neurons to precisely control their activities by light, it has become a powerful tool in neuroscience. Although the recently solved crystal structure of a chimeric ChR, C1C2, provided the structural basis for ChR, our understanding of the molecular mechanism of ChR still remains limited. Here we performed electrophysiological analyses and all-atom molecular dynamics (MD simulations, to investigate the importance of the intracellular and central constrictions of the ion conducting pore observed in the crystal structure of C1C2. Our electrophysiological analysis revealed that two glutamate residues, Glu122 and Glu129, in the intracellular and central constrictions, respectively, should be deprotonated in the photocycle. The simulation results suggested that the deprotonation of Glu129 in the central constriction leads to ion leakage in the ground state, and implied that the protonation of Glu129 is important for preventing ion leakage in the ground state. Moreover, we modeled the 13-cis retinal bound; i.e., activated C1C2, and performed MD simulations to investigate the conformational changes in the early stage of the photocycle. Our simulations suggested that retinal photoisomerization induces the conformational change toward channel opening, including the movements of TM6, TM7 and TM2. These insights into the dynamics of the ground states and the early photocycle stages enhance our understanding of the channel function of ChR.

  19. Channel nut tool

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Marvin

    2016-01-12

    A method, system, and apparatus for installing channel nuts includes a shank, a handle formed on a first end of a shank, and an end piece with a threaded shaft configured to receive a channel nut formed on the second end of the shaft. The tool can be used to insert or remove a channel nut in a channel framing system and then removed from the channel nut.

  20. Huwentoxin-XVI, an analgesic, highly reversible mammalian N-type calcium channel antagonist from Chinese tarantula Ornithoctonus huwena.

    Science.gov (United States)

    Deng, Meichun; Luo, Xuan; Xiao, Yucheng; Sun, Zhenghua; Jiang, Liping; Liu, Zhonghua; Zeng, Xiongzhi; Chen, Hanchun; Tang, Jianhua; Zeng, Weimin; Songping Liang

    2014-04-01

    N-type calcium channels play important roles in the control of neurotransmission release and transmission of pain signals to the central nervous system. Their selective inhibitors are believed to be potential drugs for treating chronic pain. In this study, a novel neurotoxin named Huwentoxin-XVI (HWTX-XVI) specific for N-type calcium channels was purified and characterized from the venom of Chinese tarantula Ornithoctonus huwena. HWTX-XVI is composed of 39 amino acid residues including six cysteines that constitute three disulfide bridges. HWTX-XVI could almost completely block the twitch response of rat vas deferens to low-frequency electrical stimulation. Electrophysiological assay indicated that HWTX-XVI specifically inhibited N-type calcium channels in rat dorsal root ganglion cells (IC50 ∼60 nM). The inhibitory effect of HWTX-XVI on N-type calcium channel currents was dose-dependent and similar to that of CTx-GVIA and CTx-MVIIA. However, the three peptides exhibited markedly different degrees of reversibility after block. The toxin had no effect on voltage-gated T-type calcium channels, potassium channels or sodium channels. Intraperitoneal injection of the toxin HWTX-XVI to rats elicited significant analgesic responses to formalin-induced inflammation pain. Toxin treatment also changed withdrawal latency in hot plate tests. Intriguingly, we found that intramuscular injection of the toxin reduced mechanical allodynia induced by incisional injury in Von Frey test. Thus, our findings suggest that the analgesic potency of HWTX-XVI and its greater reversibility could contribute to the design of a novel potential analgesic agent with high potency and low side effects. PMID:24467846

  1. Ferritin ion channel disorder inhibits Fe(II)/O2 reactivity at distant sites.

    Science.gov (United States)

    Tosha, Takehiko; Behera, Rabindra K; Theil, Elizabeth C

    2012-11-01

    Ferritins, a complex, mineralized, protein nanocage family essential for life, provide iron concentrates and oxidant protection. Protein-based ion channels and Fe(II)/O(2) catalysis initiate conversion of thousands of Fe atoms to caged, ferritin Fe(2)O(3)·H(2)O minerals. The ion channels consist of six helical segments, contributed by 3 of 12 or 24 polypeptide subunits, around the 3-fold cage axes. The channel structure guides entering Fe(II) ions toward multiple, catalytic, diiron sites buried inside ferritin protein helices, ~20 Å away from channel internal exits. The catalytic product, Fe(III)-O(H)-Fe(III), is a mineral precursor; mineral nucleation begins inside the protein cage with mineral growth in the central protein cavity (5-8 nm diameter). Amino acid substitutions that changed ionic or hydrophobic channel interactions R72D, D122R, and L134P increased ion channel structural disorder (protein crystallographic analyses) and increased Fe(II) exit [chelated Fe(II) after ferric mineral reduction/dissolution]. Since substitutions of some channel carboxylate residues diminished ferritin catalysis with no effect on Fe(II) exit, such as E130A and D127A, we investigated catalysis in ferritins with altered Fe(II) exit, R72D, D122R and L134P. The results indicate that simply changing the ionic properties of the channels, as in the R72D variant, need not change the forward catalytic rate. However, both D122R and L134P, which had dramatic effects on ferritin catalysis, also caused larger effects on channel structure and order, contrasting with R72D. All three amino acid substitutions, however, decreased the stability of the catalytic intermediate, diferric peroxo, even though overall ferritin cage structure is very stable, resisting 80 °C and 6 M urea. The localized structural changes in ferritin subdomains that affect ferritin function over long distances illustrate new properties of the protein cage in natural ferritin function and for applied ferritin uses. PMID

  2. Residual-stress measurements

    International Nuclear Information System (INIS)

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author)

  3. Residual-stress measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ezeilo, A.N.; Webster, G.A. [Imperial College, London (United Kingdom); Webster, P.J. [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  4. Sharing Residual Liability

    DEFF Research Database (Denmark)

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... allows policy makers to induce parties to undertake socially desirable care and activity levels. Traditionally, tort law systems have assigned residual liability either entirely on the tortfeasor or entirely on the victim. In this paper, we unpack the cheapest-cost-avoider principle to consider the...

  5. Residues of Chern classes

    OpenAIRE

    Suwa, Tatsuo; 諏訪, 立雄

    2003-01-01

    If we have a finite number of sections of a complex vector bundle E over a manifold M, certain Chern classes of E are localized at the singular set S, i.e., the set of points where the sections fail to be linearly independent. When S is compact, the localizations define the residues at each connected component of S by the Alexander duality. If M itself is compact, the sum of the residues is equal to the Poincaré dual of the corresponding Chern class. This type of theory is also developed for ...

  6. Residues of Chern classes

    OpenAIRE

    Suwa, Tatsuo

    2003-01-01

    If we have a finite number of sections of a complex vector bundle $E$ over a manifold $M$ , certain Chern classes of $E$ are localized at the singular set $S$ , i.e., the set of points where the sections fail to be linearly independent. When $S$ is compact, the localizations define the residues at each connected component of $S$ by the Alexander duality. If $M$ itself is compact, the sum of the residues is equal to the Poincaré dual of the corresponding Chern class. This type of theory is als...

  7. Capacity of very noisy communication channels based on Fisher information

    Science.gov (United States)

    Duan, Fabing; Chapeau-Blondeau, François; Abbott, Derek

    2016-06-01

    We generalize the asymptotic capacity expression for very noisy communication channels to now include coloured noise. For the practical scenario of a non-optimal receiver, we consider the common case of a correlation receiver. Due to the central limit theorem and the cumulative characteristic of a correlation receiver, we model this channel noise as additive Gaussian noise. Then, the channel capacity proves to be directly related to the Fisher information of the noise distribution and the weak signal energy. The conditions for occurrence of a noise-enhanced capacity effect are discussed, and the capacity difference between this noisy communication channel and other nonlinear channels is clarified.

  8. Major Channels Involved In Neuropsychiatric Disorders And Therapeutic Perspectives

    Directory of Open Access Journals (Sweden)

    Paola eImbrici

    2013-05-01

    Full Text Available Voltage-gated ion channels are important mediators of physiological functions in the central nervous system. The cyclic activation of these channels influences neurotransmitter release, neuron excitability, gene transcription and plasticity, providing distinct brain areas with unique physiological and pharmacological response. A growing body of data has implicated ion channels in the susceptibility or pathogenesis of psychiatric diseases. Indeed, population studies support the association of polymorphisms in calcium and potassium channels with the genetic risk for bipolar disorders or schizophrenia. Moreover, point mutations in calcium, sodium and potassium channel genes have been identified in some childhood developmental disorders. Finally, antibodies against potassium channel complexes occur in a series of autoimmune psychiatric diseases. Here we report recent studies assessing the role of calcium, sodium and potassium channels in bipolar disorder, schizophrenia and autism spectrum disorders, and briefly summarize promising pharmacological strategies targeted on ion channels for the therapy of mental illness and related genetic tests.

  9. Residual resistance simulation of an air spark gap switch

    CERN Document Server

    Siahlo, S E

    2015-01-01

    The numerical simulation of an air spark gap has been carried within two theoretical models. The kinetic one [1] allowed us to calculate time dependencies for the residual resistance (0.2 - 0.4 Ohm for our selection of a circuit parameters), the spark gap channel width, the electron number density, the mobility, the conductivity, the ionization degree, the magnetic field in the discharge channel, the channel inductance and the electron drift velocity. Simulating a real circuit and taking into account a spark gap residual resistance demonstrates good agreement of both models with the experimental data, while that without taking into account this resistance overestimates the maximal current in the circuit by approximately 5%.

  10. Residual stresses within sprayed coatings

    Institute of Scientific and Technical Information of China (English)

    JIANG Yi; XU Bin-shi; WANG Hai-dou

    2005-01-01

    Some important developments of residual stress researches for coating-based systems were studied. The following topics were included the sources of residual stresses in coatings: error analysis of Stoney's equation in the curvature method used for the measurement of coating residual stress, the modeling of residual stress and some analytical models for predicting the residual stresses in coatings. These topics should provide some important insights for the fail-safe design of the coating-based systems.

  11. Percentile residual life orders

    OpenAIRE

    Franco Pereira, Alba M.; Lillo, Rosa E.; Romo, Juan; Shaked, Moshe

    2011-01-01

    In this paper we study a family of stochastic orders of random variables defined via the comparison of their percentile residual life functions. Some interpretations of these stochastic orders are given, and various properties of them are derived. The relationships to other stochastic orders are also studied. Finally, some applications in reliability theory and finance are described.

  12. Wood residues in Alberta

    International Nuclear Information System (INIS)

    The forest products industry is the third largest economic sector in Alberta, producing pulp and paper, dimensional lumber, paneling, and value added products, providing some 40,000 jobs . 'Value added' is a key component of expanding economic activity within the forest products sector. Wood residues can play a key role in obtaining more value from forest resources by providing new products, serving as feedstock to energy and chemical production, and playing a role in agriculture and land reclamation. One of the principal roles of the Forest Products Development Branch of the Alberta Economics Department is to encourage the development of the industry by creating new uses for these materials and developing awareness of the scope of the resource. Distances to markets, economic competition from conventional energy sources and coordination of research efforts are substantial barriers to further development that the Forest Products Development Branch has to face daily. Some notable successes in recent years are described. These include the Wood Residue Inventory and the Wood Residue Database that provide data on availability and principal location of wood residues, also a listing of contacts at the mills who produce the materials

  13. Calmodulin modulation of ion channels and receptors

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ion channels and receptors are the structural basis for neural signaling and transmission. Recently, the function of ion channels and receptors has been demonstrated to be modulated by many intracellular and extracellular chemicals and signaling molecules. Increasing evidence indicates that the complexity and plasticity of the function of central nervous system is determined by the modulation of ion channels and receptors. Among various mechanisms, Ca 2+ signaling pathways play important roles in neuronal activity and some pathological changes. Ca 2+ influx through ion channels and receptors can modulate its further influx in a feedback way or modulate other ion channels and receptors. The common feature of the modulation is that Ca 2+ /calmodulin (CaM) is the universal mediator. CaM maintains the coordination among ion channels/receptors and intracellular Ca 2+ homeostasis by feedback modulation of ion channels/receptors activity. This review focuses on the modulating processes of ion channels and receptors mediated by CaM, and further elucidates the mechanisms of Ca 2+ signaling.

  14. Entrance channel effects in fusion reactions near the barrier: Reaction dynamics or nuclear structure?

    International Nuclear Information System (INIS)

    The origin of previously reported entrance channel effects by symmetric and asymmetric fusion reactions leading to rare earth nuclei near the Coulomb barrier is critically reviewed. Possible influences of reaction dynamics or structure effects due to the proximity of superdeformation are discussed using new charged-particle spectra and angular distributions associated with specific axn exit channels. For axn channels, nonstatistical effects in the fusion of the asymmetric entrance channel are responsible for the large difference in the spin distributions in the evaporation residues formed by symmetric and asymmetric entrance channels. Whereas GDR spectra show significant entrance channel effects, the authors find no influence on the subbarrier α spectra from possible elongated shapes associated with early reaction dynamics. New data and analyses of γ-ray multiplicity distributions from the xn exit channels show that previously reported entrance channel effects are due to mapping from l to residue spin and then to γ-ray multiplicity

  15. The Earliest Ion Channels

    Science.gov (United States)

    Pohorille, A.; Wilson, M. A.; Wei, C.

    2009-12-01

    Supplying protocells with ions required assistance from channels spanning their membrane walls. The earliest channels were most likely short proteins that formed transmembrane helical bundles surrounding a water-filled pore. These simple aggregates were capable of transporting ions with efficiencies comparable to those of complex, contemporary ion channels. Channels with wide pores exhibited little ion selectivity but also imposed only modest constraints on amino acid sequences of channel-forming proteins. Channels with small pores could have been selective but also might have required a more precisely defined sequence of amino acids. In contrast to modern channels, their protocellular ancestors had only limited capabilities to regulate ion flux. It is postulated that subsequent evolution of ion channels progressed primarily to acquire precise regulation, and not high efficiency or selectivity. It is further proposed that channels and the surrounding membranes co-evolved.

  16. Gramicidin Channels: Versatile Tools

    Science.gov (United States)

    Andersen, Olaf S.; Koeppe, Roger E., II; Roux, Benoît

    Gramicidin channels are miniproteins in which two tryptophan-rich subunits associate by means of transbilayer dimerization to form the conducting channels. That is, in contrast to other ion channels, gramicidin channels do not open and close; they appear and disappear. Each subunit in the bilayer-spanning channel is tied to the bilayer/solution interface through hydrogen bonds that involve the indole NH groups as donors andwater or the phospholipid backbone as acceptors. The channel's permeability characteristics are well-defined: gramicidin channels are selective for monovalent cations, with no measurable permeability to anions or polyvalent cations; ions and water move through a pore whose wall is formed by the peptide backbone; and the single-channel conductance and cation selectivity vary when the amino acid sequence is varied, even though the permeating ions make no contact with the amino acid side chains. Given the plethora of available experimental information—for not only the wild-type channels but also for channels formed by amino acid-substituted gramicidin analogues—gramicidin channels continue to provide important insights into the microphysics of ion permeation through bilayer-spanning channels. For similar reasons, gramicidin channels constitute a system of choice for evaluating computational strategies for obtaining mechanistic insights into ion permeation through the more complex channels formed by integral membrane proteins.

  17. A molecular switch driving inactivation in the cardiac K+ channel HERG.

    Directory of Open Access Journals (Sweden)

    David A Köpfer

    Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

  18. Multi-Channel Retailing

    Directory of Open Access Journals (Sweden)

    Dirk Morschett, Dr.,

    2005-01-01

    Full Text Available Multi-channel retailing entails the parallel use by retailing enterprises of several sales channels. The results of an online buyer survey which has been conducted to investigate the impact of multi-channel retailing (i.e. the use of several retail channels by one retail company on consumer behaviour show that the frequently expressed concern that the application of multi-channel systems in retailing would be associated with cannibalization effects, has proven unfounded. Indeed, the appropriate degree of similarity, consistency, integration and agreement achieves the exact opposite. Different channels create different advantages for consumers. Therefore the total benefit an enterprise which has a multi-channel system can offer to its consumers is larger, the greater the number of available channels. The use of multi-channel systems is associated with additional purchases in the different channels. Such systems are thus superior to those offering only one sales channel to their customers. Furthermore, multi-channel systems with integrated channels are superior to those in which the channels are essentially autonomous and independent of one another. In integrated systems, consumers can achieve synergy effects in the use of sales-channel systems. Accordingly, when appropriately formulated, multi-channel systems in retailing impact positively on consumers. They use the channels more frequently, buy more from them and there is a positive customer-loyalty impact. Multi-channel systems are strategic options for achieving customer loyalty, exploiting customer potential and for winning new customers. They are thus well suited for approaching differing and varied target groups.

  19. A new type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-magnification Gravitational Microlensing Events

    DEFF Research Database (Denmark)

    Choi, J.-Y; Shin, I.-G; Han, C.; Udalski, A.; Sumi, T.; Gould, A.; Bozza, V.; Dominik, M.; Fouque´, P.; Horne, K.; Szyman´ski, M. K.; Kubiak, M.; Soszyn´ski, I.; Pietrzyn´ski, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł.; OGLE Collaboration; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohmori, K.; Ohnishi, K.; Rattenbury, N. J.; Saito, To; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Bramich, D. M.; Snodgrass, C.; Steele, I. A.; Street, R. A.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Fang, X.-S; Grundahl, F.; Gu, C.-H; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, Allan; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Lund, M.; Lunkkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wambsganss, J.; Wertz, O.; Almeida, L. A.; Batista, V.; Christie, G.; DePoy, D. L.; Dong, Subo; Gaudi, B. S.; Henderson, C.; Jablonski, F.; Lee, C.-U; McCormick, J.; McGregor, D.; Moorhouse, D.; Natusch, T.; Ngan, H.; Pogge, R. W.; Tan, T.-G; Thornley, G.; Yee, J. C.; Albrow, M. D.; Bachelet, E.; Beaulieu, J.-P; Brillant, S.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J.-B; Menzies, J. W.; Sahu, K. C.; Zub, M.

    2012-01-01

    High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally...... very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with Δχ2 ~ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference...

  20. Reconstructive techniques for creation of catheterizable channels: tunneled and nipple valve channels

    OpenAIRE

    Levy, Mya E.; Elliott, Sean P.

    2016-01-01

    Cutaneous catheterizable channels allow for continent bladder emptying when an alternate route is desired. The goals of channel creation in the neurogenic bladder population are successful urine elimination, renal preservation, continence and lastly cosmesis. In addition to a particular surgeon’s comfort and experience with a given procedure, individual patient factors such as medical comorbidities, anatomic factors, and occupational function should be central to the selection of a surgical a...

  1. Major Channels Involved In Neuropsychiatric Disorders And Therapeutic Perspectives

    OpenAIRE

    Paola eImbrici; Diana eConte Camerino; Domenico eTricarico

    2013-01-01

    Voltage-gated ion channels are important mediators of physiological functions in the central nervous system. The cyclic activation of these channels influences neurotransmitter release, neuron excitability, gene transcription and plasticity, providing distinct brain areas with unique physiological and pharmacological response. A growing body of data has implicated ion channels in the susceptibility or pathogenesis of psychiatric diseases. Indeed, population studies support the association of ...

  2. Europa central

    Directory of Open Access Journals (Sweden)

    Karel BARTOSEK

    2010-02-01

    Full Text Available La investigación francesa continúa interesándose por Europa Central. Desde luego, hay límites a este interés en el ambiente general de mi nueva patria: en la ignorancia, producto del largo desinterés de Francia por este espacio después de la Segunda Guerra Mundial, y en el comportamiento y la reflexión de la clase política y de los medios de comunicación (una anécdota para ilustrar este ambiente: durante la preparación de nuestro coloquio «Refugiados e inmigrantes de Europa Central en el movimiento antifascista y la Resistencia en Francia, 1933-1945», celebrado en París en octubre de 1986, el problema de la definición fue planteado concreta y «prácticamente». ¡Y hubo entonces un historiador eminente, para quién Alemania no formaría parte de Europa Central!.

  3. Pannexin 1 channels in skeletal muscles

    Science.gov (United States)

    Cea, Luis A.; Riquelme, Manuel A.; Vargas, Anibal A.; Urrutia, Carolina; Sáez, Juan C.

    2014-01-01

    Normal myotubes and adult innervated skeletal myofibers express the glycoprotein pannexin1 (Panx1). Six of them form a “gap junction hemichannel-like” structure that connects the cytoplasm with the extracellular space; here they will be called Panx1 channels. These are poorly selective channels permeable to ions, small metabolic substrate, and signaling molecules. So far little is known about the role of Panx1 channels in muscles but skeletal muscles of Panx1−/− mice do not show an evident phenotype. Innervated adult fast and slow skeletal myofibers show Panx1 reactivity in close proximity to dihydropyridine receptors in the sarcolemma of T-tubules. These Panx1 channels are activated by electrical stimulation and extracellular ATP. Panx1 channels play a relevant role in potentiation of muscle contraction because they allow release of ATP and uptake of glucose, two molecules required for this response. In support of this notion, the absence of Panx1 abrogates the potentiation of muscle contraction elicited by repetitive electrical stimulation, which is reversed by exogenously applied ATP. Phosphorylation of Panx1 Thr and Ser residues might be involved in Panx1 channel activation since it is enhanced during potentiation of muscle contraction. Under denervation, Panx1 levels are upregulated and this partially explains the reduction in electrochemical gradient, however its absence does not prevent denervation-induced atrophy but prevents the higher oxidative state. Panx1 also forms functional channels at the cell surface of myotubes and their functional state has been associated with intracellular Ca2+ signals and regulation of myotube plasticity evoked by electrical stimulation. We proposed that Panx1 channels participate as ATP channels and help to keep a normal oxidative state in skeletal muscles. PMID:24782784

  4. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  5. Wear inspection for fuel channels in HANARO

    International Nuclear Information System (INIS)

    It has been observed that fuel assemblies have mechanical damage on some components due to the flow-induced vibration in the fuel channels. The major damage was the fretting-wear on the bottom end plates and spacer plates. Both the components are aluminum but cause the fretting-wear on the corresponding surfaces of the zirconium fuel channels. Also the bottom guide arms and top springs of the fuel are considered to be major parts that cause wear on the fuel channels. Therefore, the inspection of the inner surfaces of the fuel channels is required from a lifetime point of view. It is very difficult and time-consuming work to remove and install the fuel channels because of their inherent characteristics and the physical interference of other components in the reactor core. Thus we developed special tools for the inspection of the fuel channels by using an impression material without the removal of the reactor components. The impression material is a compound to replicate the damage of the fuel channels within a limited working time considering the hardening time as well as the radiation effect. The wear-inspection tool is a mechanical tool to press the impression compound against the inner walls of the fuel channels where the fuel components contact. The inspection tool has 36 molding cups that are operated in radial directions by turning the central rod with a fuel-handling tool from the pool top 12m above the reactor core. The same concept but a more compact design is applied to the cylindrical fuel channel. The wear inspection was successfully accomplished for a few fuel channels. The results show visible wear marks on a hexagonal fuel channel at the positions corresponding to fuel components such as the bottom guide arms and top springs. The wear damage is slight, approximately 0.2mm depth, in comparison with the thickness (1.6mm) of the fuel channel. No visible wear mark has been found in the cylindrical flow tubes so far. The wear inspection is being continued

  6. Designing with residual materials

    OpenAIRE

    Walhout, W.; Wever, R; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies remain in the more artistic domain, with relatively labor-intensive products, and small batch sizes. Moving beyond such small-scale activities would likely require a standardized innovation process....

  7. Dynamic channel allocation

    OpenAIRE

    Kaminsky, Andrew D.

    2003-01-01

    Approved for public release; distribution in unlimited. Dynamic Channel Allocation (DCA) offers the possibility of capturing unused channel capacity by allocating unused resources between competing network nodes. This can reduce or possibly eliminate channels sitting idle while information awaits transmission. This holds potential for increasing throughput on bandwidth constrained networks. The purpose of this thesis is to examine the techniques used to allocate channels on demand and acc...

  8. Residual contaminants in milk

    Directory of Open Access Journals (Sweden)

    Nevijo Zdolec

    2006-07-01

    Full Text Available Various chemical agents are used during the whole production chain of milk and dairy products. Production of feedingstuffs is accompanied with pesticide usage, which may remain in environment, thus are transported through feeding into animals, animal products and finally in human organism. Preparation procedure and storage conditions of feed also influence on milk safety in the sense of mycotoxins entering into the food chain. Chemical agents are, on daily basis, used on dairy farms either as detergents or disinfections. The residuals of cleaning agents might remain in milk if the cleaning agents and its dosage are not performed adequately. Besides already mentioned agents, a great influence in milk production can bee seen through veterinary drugs usage, particularly antibacterial drugs (mastitis. Proper application of drugs and by following legal recommendation, a by-reactions can be avoided such as allergic reaction in humans, development of resisting bacteria or even undesirable influence on starter cultures in dairy products manufacture. The maximum residue limits, monitoring plan as well as sampling procedures are set up within the harmonization of Croatian and European legislation, in order to provide official control of residues in foodstuffs of animal origin.

  9. Discovery and characterisation of a novel toxin from Dendroaspis angusticeps, named Tx7335, that activates the potassium channel KcsA.

    Science.gov (United States)

    Rivera-Torres, Iván O; Jin, Tony B; Cadene, Martine; Chait, Brian T; Poget, Sébastien F

    2016-01-01

    Due to their central role in essential physiological processes, potassium channels are common targets for animal toxins. These toxins in turn are of great value as tools for studying channel function and as lead compounds for drug development. Here, we used a direct toxin pull-down assay with immobilised KcsA potassium channel to isolate a novel KcsA-binding toxin (called Tx7335) from eastern green mamba snake (Dendroaspis angusticeps) venom. Sequencing of the toxin by Edman degradation and mass spectrometry revealed a 63 amino acid residue peptide with 4 disulphide bonds that belongs to the three-finger toxin family, but with a unique modification of its disulphide-bridge scaffold. The toxin induces a dose-dependent increase in both open probabilities and mean open times on KcsA in artificial bilayers. Thus, it unexpectedly behaves as a channel activator rather than an inhibitor. A charybdotoxin-sensitive mutant of KcsA exhibits similar susceptibility to Tx7335 as wild-type, indicating that the binding site for Tx7335 is distinct from that of canonical pore-blocker toxins. Based on the extracellular location of the toxin binding site (far away from the intracellular pH gate), we propose that Tx7335 increases potassium flow through KcsA by allosterically reducing inactivation of the channel. PMID:27044983

  10. Electrostatic tuning of permeation and selectivity in aquaporin water channels

    DEFF Research Database (Denmark)

    Jensen, Mogens O Stibius; Tajkhorshid, E.; Schulten, K.

    2003-01-01

    stronger than water-protein interactions, except near a conserved, positively charged Arg residue. We find that variations of the protein electrostatic field through the channel, owing to preserved structural features, completely explain the bipolar orientation of water. This orientation persists despite......Water permeation and electrostatic interactions between water and channel are investigated in the Escherichia coli glycerol uptake facilitator GlpF, a member of the aquaporin water channel family, by molecular dynamics simulations. A tetrameric model of the channel embedded in a 16:0/ 18:1c9......-palmitoyloleylphosphatidylethanolamine membrane was used for the simulations. During the simulations, water molecules pass through the channel in single file. The movement of the single. le water molecules through the channel is concerted, and we show that it can be described by a continuous-time random-walk model. The integrity of the...

  11. KV7 potassium channels

    DEFF Research Database (Denmark)

    Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

    2014-01-01

    Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

  12. Quantum Channels With Memory

    International Nuclear Information System (INIS)

    Quantum memory channels represent a very general, yet simple and comprehensible model for causal processes. As such they have attracted considerable research interest, mostly aimed on their transfer capabilities and structure properties. Most notably it was shown that memory channels can be implemented via physically naturally motivated collision models. We also define the concept of repeatable channels and show that only unital channels can be implemented repeat ably with pure memory channels. In the special case of qubit channels we also show that every unital qubit channel has a repeatable implementation. We also briefly explore the possibilities of stroboscopical simulation of channels and show that all random unitary channels can be stroboscopically simulated. Particularly in qubit case, all indivisible qubit channels are also random unitary, hence for qubit all indivisible channels can be stroboscopically simulated. Memory channels also naturally capture the framework of correlated experiments. We develop methods to gather and interpret data obtained in such setting and in detail examine the two qubit case. We also show that for control unitary interactions the measured data will never contradict a simple unitary evolution. Thus no memory effects can be spotted then. (author)

  13. Quantum Multiple Access Channel

    Institute of Scientific and Technical Information of China (English)

    侯广; 黄民信; 张永德

    2002-01-01

    We consider the transmission of classical information over a quantum channel by many senders, which is a generalization of the two-sender case. The channel capacity region is shown to be a convex hull bound by the yon Neumann entropy and the conditional yon Neumann entropies. The result allows a reasonable distribution of channel capacity over the senders.

  14. Desynched channels on IRCnet

    CERN Document Server

    Hansen, Michael

    2008-01-01

    In this paper we describe what a desynchronised channel on IRC is. We give procedures on how to create such a channel and how to remove desynchronisation. We explain which types of desynchronisation there are, what properties desynchronised channels have, and which properties can be exploited.

  15. SLO2 Channels Are Inhibited by All Divalent Cations That Activate SLO1 K+ Channels.

    Science.gov (United States)

    Budelli, Gonzalo; Sun, Qi; Ferreira, Juan; Butler, Alice; Santi, Celia M; Salkoff, Lawrence

    2016-04-01

    Two members of the family of high conductance K(+)channels SLO1 and SLO2 are both activated by intracellular cations. However, SLO1 is activated by Ca(2+)and other divalent cations, while SLO2 (Slack or SLO2.2 from rat) is activated by Na(+) Curiously though, we found that SLO2.2 is inhibited by all divalent cations that activate SLO1, with Zn(2+)being the most effective inhibitor with an IC50of ∼8 μmin contrast to Mg(2+), the least effective, with an IC50of ∼ 1.5 mm Our results suggest that divalent cations are not SLO2 pore blockers, but rather inhibit channel activity by an allosteric modification of channel gating. By site-directed mutagenesis we show that a histidine residue (His-347) downstream of S6 reduces inhibition by divalent cations. An analogous His residue present in some CNG channels is an inhibitory cation binding site. To investigate whether inhibition by divalent cations is conserved in an invertebrate SLO2 channel we cloned the SLO2 channel fromDrosophila(dSLO2) and compared its properties to those of rat SLO2.2. We found that, like rat SLO2.2, dSLO2 was also activated by Na(+)and inhibited by divalent cations. Inhibition of SLO2 channels in mammals andDrosophilaby divalent cations that have second messenger functions may reflect the physiological regulation of these channels by one or more of these ions. PMID:26823461

  16. Repair cycle optimization for multi-channel engineering systems

    International Nuclear Information System (INIS)

    Conceptual definition of mathematical problem related to the evaluation of residual service-life of multi-channel engineering systems (systems comprising N similar process channels for the RBMK-type reactors are included, in particular) and optimization of the cycles of overhaul and scheduled repairs is considered. Integral economic index of aging permitting not only to predict residual service-life of the system but also to evaluate from technico-economical viewpoint the optimal strategy of overhaul schedulled repairs is obtained. 2 refs

  17. Voltage-Gated Calcium Channels in Nociception

    Science.gov (United States)

    Yasuda, Takahiro; Adams, David J.

    Voltage-gated calcium channels (VGCCs) are a large and functionally diverse group of membrane ion channels ubiquitously expressed throughout the central and peripheral nervous systems. VGCCs contribute to various physiological processes and transduce electrical activity into other cellular functions. This chapter provides an overview of biophysical properties of VGCCs, including regulation by auxiliary subunits, and their physiological role in neuronal functions. Subsequently, then we focus on N-type calcium (Cav2.2) channels, in particular their diversity and specific antagonists. We also discuss the role of N-type calcium channels in nociception and pain transmission through primary sensory dorsal root ganglion neurons (nociceptors). It has been shown that these channels are expressed predominantly in nerve terminals of the nociceptors and that they control neurotransmitter release. To date, important roles of N-type calcium channels in pain sensation have been elucidated genetically and pharmacologically, indicating that specific N-type calcium channel antagonists or modulators are particularly useful as therapeutic drugs targeting chronic and neuropathic pain.

  18. Reconstructive techniques for creation of catheterizable channels: tunneled and nipple valve channels.

    Science.gov (United States)

    Levy, Mya E; Elliott, Sean P

    2016-02-01

    Cutaneous catheterizable channels allow for continent bladder emptying when an alternate route is desired. The goals of channel creation in the neurogenic bladder population are successful urine elimination, renal preservation, continence and lastly cosmesis. In addition to a particular surgeon's comfort and experience with a given procedure, individual patient factors such as medical comorbidities, anatomic factors, and occupational function should be central to the selection of a surgical approach. An ideal channel is one that is short, straight, and well supported by associated blood supply and surrounding adventitia, so as to minimize difficulty with catheterization. Two types of channel continence mechanisms are discussed at length in this review-the tunneled channel, and the nipple valve. The appendicovesicostomy (Mitrofanoff), and reconfigured ileum (Yang-Monti) are both tunneled channels. The ileocecal valve is a commonly used nipple valve and provides continence when reinforced. The continent catheterizable ileal cecocystoplasty (CCIC) is an example of this channel technique. This method couples a tapered ileal limb as a catheterizable channel, the ileocecal valve as the continence mechanism, and the cecum and ascending colon as a bladder augmentation. While this procedure has higher perioperative complications relative to a simple tunneled channel, it has increased channel length flexibility and is also coupled with a bladder augment, which is completely performed using one bowel segment. Continent channel creation in adults can improve quality of life and minimize morbidity associated with neurogenic bladder. However, the decision to proceed with creation of a catheterizable channel should be made only after careful consideration of the patient's medical comorbidities, physical abilities social support, and surgeon experience. PMID:26904419

  19. A negative charge in transmembrane segment 1 of domain II of the cockroach sodium channel is critical for channel gating and action of pyrethroid insecticides

    International Nuclear Information System (INIS)

    Voltage-gated sodium channels are the primary target of pyrethroids, an important class of synthetic insecticides. Pyrethroids bind to a distinct receptor site on sodium channels and prolong the open state by inhibiting channel deactivation and inactivation. Recent studies have begun to reveal sodium channel residues important for pyrethroid binding. However, how pyrethroid binding leads to inhibition of sodium channel deactivation and inactivation remains elusive. In this study, we show that a negatively charged aspartic acid residue at position 802 (D802) located in the extracellular end of transmembrane segment 1 of domain II (IIS1) is critical for both the action of pyrethroids and the voltage dependence of channel activation. Charge-reversing or -neutralizing substitutions (K, G, or A) of D802 shifted the voltage dependence of activation in the depolarizing direction and reduced channel sensitivity to deltamethrin, a pyrethroid insecticide. The charge-reversing mutation D802K also accelerated open-state deactivation, which may have counteracted the inhibition of sodium channel deactivation by deltamethrin. In contrast, the D802G substitution slowed open-state deactivation, suggesting an additional mechanism for neutralizing the action of deltamethrin. Importantly, Schild analysis showed that D802 is not involved in pyrethroid binding. Thus, we have identified a sodium channel residue that is critical for regulating the action of pyrethroids on the sodium channel without affecting the receptor site of pyrethroids.

  20. Capacities of Grassmann channels

    CERN Document Server

    Bradler, Kamil; Jauregui, Rocio

    2010-01-01

    A new class of quantum channels called Grassmann channels is introduced and their classical and quantum capacity is calculated. The channel class appears in a study of the two-mode squeezing operator constructed from operators satisfying the fermionic algebra. We compare Grassmann channels with the channels induced by the bosonic two-mode squeezing operator. Among other results, we challenge the relevance of calculating entanglement measures to assess or compare the ability of bosonic and fermionic states to send quantum information to uniformly accelerated frames.

  1. Modeling Permeation Energetics in the KcsA Potassium Channel

    OpenAIRE

    Garofoli, S.; Jordan, P C

    2003-01-01

    The thermodynamics of cation permeation through the KcsA K+ channel selectivity filter is studied from the perspective of a physically transparent semimicroscopic model using Monte Carlo free energy integration. The computational approach chosen permits dissection of the separate contributions to ionic stabilization arising from different parts of the channel (selectivity filter carbonyls, single-file water, cavity water, reaction field of bulk water, inner helices, ionizable residues). All f...

  2. Source and Channel Coding for Correlated Sources Over Multiuser Channels

    OpenAIRE

    Gunduz, Deniz; Erkip, Elza; Goldsmith, Andrea; Poor, H. Vincent

    2008-01-01

    Source and channel coding over multiuser channels in which receivers have access to correlated source side information is considered. For several multiuser channel models necessary and sufficient conditions for optimal separation of the source and channel codes are obtained. In particular, the multiple access channel, the compound multiple access channel, the interference channel and the two-way channel with correlated sources and correlated receiver side information are considered, and the o...

  3. Study on properties of residue-residue contacts in protein

    Institute of Scientific and Technical Information of China (English)

    王向红; 柯见洪; 郑亦庄; 陈爱; 徐银香

    2004-01-01

    Residue-residue contacts are very important in forming protein structure. In this work, we calculated the average probability of residue-residue contacts in 470 globular proteins and analyzed the distribution of contacts in the different interval of residues using Contacts of Structural Units (CSU) and Structural Classification (SCOP) software. It was found that the relationship between the average probability PL and the residue distance L for four structural classes of proteins could be expressed as lgPL=a+b×L, where a and b are coefficients. We also discussed the connection between two aspects of proteins which have equal array residue number and found that the distribution probability was stable (or un-stable) if the proteins had the same (or different) comnact (for examnle svnthase) in the same structural class.

  4. Study on properties of residue-residue contacts in protein

    Institute of Scientific and Technical Information of China (English)

    王向红; 柯见洪; 郑亦庄; 陈爱; 徐银香

    2004-01-01

    Residue-residue contacts are very important in forming protein structure. In this work, we calculated theaverage probability of residue-residue contacts in 470 globular proteins and analyzed the distribution of contacts in thedifferent interval of residues using Contacts of Structural Units (CSU) and Structural Classification (SCOP) software. Itwas found that the relationship between the average probability -PL and the residue distance L for four structural classes ofproteins could be expressed as lgPL=a+b×L, where a and b are coefficients. We also discussed the connection between twoaspects of proteins which have equal array residue number and found that the distribution probability was stable (or un-stable) if the proteins had the same (or different) compact (for example synthase) in the same structural class.

  5. Cognitive residues of similarity

    OpenAIRE

    OToole, Stephanie; Keane, Mark T.

    2013-01-01

    What are the cognitive after-effects of making a similarity judgement? What, cognitively, is left behind and what effect might these residues have on subsequent processing? In this paper, we probe for such after-effects using a visual search task, performed after a task in which pictures of real-world objects were compared. So, target objects were first presented in a comparison task (e.g., rate the similarity of this object to another) thus, presumably, modifying some of their features befor...

  6. Compound Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Shlomo Shamai (Shitz

    2009-01-01

    Full Text Available This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom (s.d.o.f. are derived for the degraded case with one receiver. Schemes to achieve the s.d.o.f. for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable s.d.o.f. is given for the general case.

  7. Compound Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Kramer Gerhard

    2009-01-01

    Full Text Available Abstract This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom ( are derived for the degraded case with one receiver. Schemes to achieve the for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable is given for the general case.

  8. Bioenergy from sisal residues

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  9. The circulation of the Mozambique channel

    Science.gov (United States)

    Sætre, Roald; Da Silva, António Jorge

    1984-05-01

    Based on hydrographic data from 1977 to 1980 off the coast of Mozambique and historical data from the Mozambique Channel, the general circulation pattern of the area is described. The circulation pattern is characterized by the influence of three anticyclonic gyres covering the northern, the central, and the southern parts of the channel. Additionally, smaller cyclonic eddies are observed, of which some probably are topographically induced. The results strongly indicate that in the upper 1000 m the role of the Mozambique Current as one of the tributaries to the Agulhas Current is of minor significance and draw into question the concept of the Mozambique Current as a continuous one.

  10. Channel capacity and error exponents of variable rate adaptive channel coding for Rayleigh fading channels

    OpenAIRE

    Lau, KN

    1999-01-01

    We have evaluated the information theoretical performance of variable rate adaptive channel coding for Rayleigh fading channels. The channel states are detected at the receiver and fed back to the transmitter by means of a noiseless feedback link. Based on the channel state informations, the transmitter can adjust the channel coding scheme accordingly. Coherent channel and arbitrary channel symbols with a fixed average transmitted power constraint are assumed. The channel capacity and the err...

  11. Quantum broadcast channels

    CERN Document Server

    Yard, J; Devetak, I; Yard, Jon; Hayden, Patrick; Devetak, Igor

    2006-01-01

    We analyze quantum broadcast channels, which are quantum channels with a single sender and many receivers. Focusing on channels with two receivers for simplicity, we generalize a number of results from the network Shannon theory literature which give the rates at which two senders can receive a common message, while a personalized one is sent to one of them. Our first collection of results applies to channels with a classical input and quantum outputs. The second class of theorems we prove concern sending a common classical message over a quantum broadcast channel, while sending quantum information to one of the receivers. The third group of results we obtain concern communication over an isometry, giving the rates at quantum information can be sent to one receiver, while common quantum information is sent to both, in the sense that tripartite GHZ entanglement is established. For each scenario, we provide an additivity proof for an appropriate class of channels, yielding single-letter characterizations of the...

  12. Ion movement through gramicidin A channels. Interfacial polarization effects on single-channel current measurements.

    OpenAIRE

    Andersen, O S

    1983-01-01

    Gramicidin A single-channel current-voltage characteristics were studied at low permeant ion concentrations and very high applied potentials. The purpose of these experiments was to elucidate the basis for the small, but definite, voltage dependence observed under these circumstances. It was found that this residual voltage dependence is a reflection of interfacial polarization effects, similar to those proposed by Walz et al. (Biophys. J. 9:1150-1159). It will be concluded that there exists ...

  13. Open-channel hydraulics

    International Nuclear Information System (INIS)

    This text discusses the following: concepts of fluid flow; the momentum principle; computation of uniform flow; design of channels; and turbulent diffusion and dispersion in steady open-channel flow. Emphasis is concerned only with the flow of water in channels where the water is not transporting significant quantities of air or sediment. The text contains quite a few examples demonstrating the application of the presented principles

  14. Bank Liabilities Channel

    OpenAIRE

    Quadrini, Vincenzo

    2014-01-01

    The financial intermediation sector is important not only for channeling resources from agents in excess of funds to agents in need of funds (lending channel). By issuing liabilities it also creates financial assets held by other sectors of the economy for insurance purpose. When the intermediation sector creates less liabilities or their value falls, agents are less willing to engage in activities that are individually risky but desirable in aggregate (bank liabilities channel). The paper st...

  15. Bank Liabilities Channel

    OpenAIRE

    Vincenzo Quadrini

    2015-01-01

    The financial intermediation sector is important not only for channeling resources from agents in excess of funds to agents in need of funds (lending channel). By issuing liabilities it also creates financial assets held by other sectors of the economy for insurance purpose. When the intermediation sector creates less liabilities or their value falls, agents are less willing to engage in activities that are individually risky but desirable in aggregate (bank liabilities channel). The paper st...

  16. HIPPI and Fibre Channel

    International Nuclear Information System (INIS)

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background

  17. Residual symmetries in the presence of an EM background

    Energy Technology Data Exchange (ETDEWEB)

    Carrion, H.L.; Rojas, M.; Toppan, F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]. E-mail: hleny@cbpf.br; mrojas@cbpf.br; toppan@cbpf.br

    2002-08-01

    The symmetry algebra of a QFT in the presence of an external EM background (named 'residual symmetry') is investigated within a Lie-algebraic, model independent scheme. Some results previously encountered in the literature are here extended. In particular we compute the symmetry algebra for a constant EM background in D = 3 and D = 4 dimensions. In D = 3 dimensions the residual symmetry algebra is isomorphic to u(1) +P{sub c}(2), with P{sub c}(2) the centrally extended 2-dimensional Poincare algebra. In D = 4 dimension the generic residual symmetry algebra is given by a seven-dimensional solvable Lie algebra which is explicitly computed. residual symmetry algebras are also computed for specific non-constant EM backgrounds. (author)

  18. Micro-mechanisms of residual oil mobilization by viscoelastic fluids

    Institute of Scientific and Technical Information of China (English)

    Zhang Lijuan; Yue Xiang'an; Guo Fenqiao

    2008-01-01

    Four typical types of residual oil, residual oil trapped in dead ends, oil ganglia in pore throats,oil at pore comers and oil film adhered to pore walls, were studied. According to main pore structure characteristics and the fundamental morphological features of residual oil, four displacement models for residual oil were proposed, in which pore-scale flow behavior of viscoelastic fluid was analyzed by a numerical method and micro-mechanisms for mobilization of residual oil were discussed. Calculated results indicate that the viscoelastic effect enhances micro displacement efficiency and increases swept volume. For residual oil trapped in dead ends, the flow field of viscoelastic fluid is developed in dead ends more deeply, resulting in more contact with oil by the displacing fluid, and consequently increasing swept volume. In addition, intense viscoelastic vortex has great stress, under which residual oil becomes small oil ganglia, and finally be carried into main channels. For residual oil at pore throats, its displacement mechanisms are similar to the oil trapped in dead ends. Vortices are developed in the depths of the throats and oil ganglia become smaller. Besides, viscoelastic fluid causes higher pressure drop on oil ganglia, as a driving force, which can overcome capillary force, consequently, flow direction can be changed and the displacing fluid enter smaller throats. For oil at pore comers, viscoelastic fluid can enhance displacement efficiency as a result of greater velocity and stress near the comers. For residual oil adhered to pore wall,viscoelastic fluid can provide a greater displacing force on the interface between viscoelastic fluid and oil,thus, making it easier to exceed the minimum interfacial tension for mobilizing the oil film.

  19. Potassium channels--multiplicity and challenges.

    Science.gov (United States)

    Jenkinson, Donald H

    2006-01-01

    The development of our knowledge of the function, structure and pharmacology of K(+) channels is briefly outlined. This is the most diverse of all the ion channel families with at least 75 coding genes in mammals. Alternative splicing as well as variations in the channel subunits and accessory proteins that co-assemble to form the functional channel add to the multiplicity. Whereas diversity of this order suggests that it may be possible to develop new classes of drug, for example, for immunomodulation and some diseases of the central nervous system, the ubiquity of K(+) channels imposes stringent requirements for selectivity. Animal toxins from the snake, bee and scorpion provide useful leads, though only in a few instances (e.g. with apamin) it has been possible to produce non-peptidic analogues of high potency. The scale of the resources needed to identify, and characterize fully, specific K(+) channel as targets and then develop modulators with the required selectivity presents a challenge to both academic and applied pharmacologists. PMID:16402122

  20. Symmetrization for redundant channels

    Science.gov (United States)

    Tulplue, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor)

    1988-01-01

    A plurality of redundant channels in a system each contain a global image of all the configuration data bases in each of the channels in the system. Each global image is updated periodically from each of the other channels via cross channel data links. The global images of the local configuration data bases in each channel are separately symmetrized using a voting process to generate a system signal configuration data base which is not written into by any other routine and is available for indicating the status of the system within each channel. Equalization may be imposed on a suspect signal and a number of chances for that signal to heal itself are provided before excluding it from future votes. Reconfiguration is accomplished upon detecting a channel which is deemed invalid. A reset function is provided which permits an externally generated reset signal to permit a previously excluded channel to be reincluded within the system. The updating of global images and/or the symmetrization process may be accomplished at substantially the same time within a synchronized time frame common to all channels.

  1. Residual gas analyzer calibration

    Science.gov (United States)

    Lilienkamp, R. H.

    1972-01-01

    A technique which employs known gas mixtures to calibrate the residual gas analyzer (RGA) is described. The mass spectra from the RGA are recorded for each gas mixture. This mass spectra data and the mixture composition data each form a matrix. From the two matrices the calibration matrix may be computed. The matrix mathematics requires the number of calibration gas mixtures be equal to or greater than the number of gases included in the calibration. This technique was evaluated using a mathematical model of an RGA to generate the mass spectra. This model included shot noise errors in the mass spectra. Errors in the gas concentrations were also included in the valuation. The effects of these errors was studied by varying their magnitudes and comparing the resulting calibrations. Several methods of evaluating an actual calibration are presented. The effects of the number of gases in then, the composition of the calibration mixture, and the number of mixtures used are discussed.

  2. Finite Element Analysis and Experiment Research on Surface Residual Stress of Ceramics Grinding

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The theoretical model of residual stress of ceramics grinding has been established applying thermal elastoplastic mechanics theory. While grinding at the course of grinding wheel moved along workpiece surface the distributing regulation of residual stress can be simplified into thermal elastioplastic mechanical issue, under the action of the both moving centralized force and heat source. Calculating and evaluating of surface residual stress using current procedure of finite element analysis which has been...

  3. Adaptive Redunant Residue Number System Coded Multicarrier Modulation

    OpenAIRE

    Keller, T.; Liew, T.H.; Hanzo, L.

    2000-01-01

    The novel class of nonbinary maximum minimum distance redundant residue number system (RRNS) codes is iinvoked in the context of adaptively RRNS coded, symbol-by-symbol adaptive multicarrier modulation, in order to combat the effects of frequency-selective fading inflicted by dispersive wide-band channels. The system’s performance can be adjusted in order to maintain a given target bit error rate (BER) and bit per symbol (BPS)performance. The proposed adaptive RRNS scheme outperforms the conv...

  4. P-matrix residues in the bag model

    International Nuclear Information System (INIS)

    The Jaffe-Low prescription for extracting P-matrix residues from the bag model is discussed and an attempt is made to derive a better result. It is found that the Jaffe-Low result can be justifiably increased by a factor of 4/3, bringing it into better agreement with experiment. There remain large uncertainties surrounding the nature of corrections for quark and channel masses

  5. Materials recovery from shredder residues

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, E. J.; Jody, B. J.; Pomykala, J., Jr.

    2000-07-24

    Each year, about five (5) million ton of shredder residues are landfilled in the US. Similar quantities are landfilled in Europe and the Pacific Rim. Landfilling of these residues results in a cost to the existing recycling industry and also represents a loss of material resources that are otherwise recyclable. In this paper, the authors outline the resources recoverable from typical shredder residues and describe technology that they have developed to recover these resources.

  6. Surgical Treatment of Residual Esotropia

    OpenAIRE

    Mravičić, Ivana; Gabrić, Nikica; Pasalić, Adis; Glavota, Vlade; Drača, Nataša

    2011-01-01

    Residual esotropia is a common problem following bilateral medial rectus (MR) recessions for esotropia. The patient was 30 years old men who underwent billateral MR recession of both eyes in the childhood. Recession was repeated on the right eye few years after the first surgery, but residual esotropia progressed. Prior to our surgery residual angle of esotropia was 50PD° with restriction of abduction and elevation of the left eye. Sinechiolysis et myectomia of right MR and sinech...

  7. Mode Switching for the Multi-Antenna Broadcast Channel Based on Delay and Channel Quantization

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2009-01-01

    Full Text Available Imperfect channel state information degrades the performance of multiple-input multiple-output (MIMO communications; its effects on single-user (SU and multiuser (MU MIMO transmissions are quite different. In particular, MU-MIMO suffers from residual interuser interference due to imperfect channel state information while SU-MIMO only suffers from a power loss. This paper compares the throughput loss of both SU and MU-MIMO in the broadcast channel due to delay and channel quantization. Accurate closed-form approximations are derived for achievable rates for both SU and MU-MIMO. It is shown that SU-MIMO is relatively robust to delayed and quantized channel information, while MU-MIMO with zero-forcing precoding loses its spatial multiplexing gain with a fixed delay or fixed codebook size. Based on derived achievable rates, a mode switching algorithm is proposed, which switches between SU and MU-MIMO modes to improve the spectral efficiency based on average signal-to-noise ratio (SNR, normalized Doppler frequency, and the channel quantization codebook size. The operating regions for SU and MU modes with different delays and codebook sizes are determined, and they can be used to select the preferred mode. It is shown that the MU mode is active only when the normalized Doppler frequency is very small, and the codebook size is large.

  8. Identification of a pharmacophore of SKCa channel blockers.

    Science.gov (United States)

    Dilly, Sebastien; Graulich, Amaury; Farce, Amaury; Seutin, Vincent; Liegeois, Jean-Francois; Chavatte, Philippe

    2005-12-01

    Small conductance calcium-activated potassium channels (SK) are widely expressed throughout the central nervous system (CNS) and the periphery. Three subtypes of SK channels have so far been identified in different parts of the brain. Activation of the SK channels by a rise in intracellular calcium leads to the hyperpolarisation of the membrane, reducing cell excitability. Blocking the SK channels might be beneficial in the treatment of depression, Parkinson's disease and cognitive disorders. However, few blockers of SK channels have been characterized. In this study, a pharmacophoric model of SK channels blockers is presented. It is based on a series of nonpeptidic compounds and apamin, a peptidic blocker. To create the pharmacophore model, the conformational space of nonpeptidic blockers was investigated to generate a series of distance constraints applied to a simulated annealing study of apamin. The resulting conformation was superimposed with the nonpeptidic blockers to give a pharmacophore. PMID:16408787

  9. Microwave emission and crop residues

    Science.gov (United States)

    Jackson, Thomas J.; O'Neill, Peggy E.

    1991-01-01

    A series of controlled experiments were conducted to determine the significance of crop residues or stubble in estimating the emission of the underlying soil. Observations using truck-mounted L and C band passive microwave radiometers showed that for dry wheat and soybeans the dry residue caused negligible attenuation of the background emission. Green residues, with water contents typical of standing crops, did have a significant effect on the background emission. Results for these green residues also indicated that extremes in plant structure, as created using parallel and perpendicular stalk orientations, can cause very large differences in the degree of attenuation.

  10. Mechanosensor Channels in Mammalian Somatosensory Neurons

    Directory of Open Access Journals (Sweden)

    Patrick Delmas

    2007-09-01

    Full Text Available Mechanoreceptive sensory neurons innervating the skin, skeletal muscles andviscera signal both innocuous and noxious information necessary for proprioception, touchand pain. These neurons are responsible for the transduction of mechanical stimuli intoaction potentials that propagate to the central nervous system. The ability of these cells todetect mechanical stimuli impinging on them relies on the presence of mechanosensitivechannels that transduce the external mechanical forces into electrical and chemical signals.Although a great deal of information regarding the molecular and biophysical properties ofmechanosensitive channels in prokaryotes has been accumulated over the past two decades,less is known about the mechanosensitive channels necessary for proprioception and thesenses of touch and pain. This review summarizes the most pertinent data onmechanosensitive channels of mammalian somatosensory neurons, focusing on theirproperties, pharmacology and putative identity.

  11. Exploring the Dynamics of the TWIK-1 Channel.

    Science.gov (United States)

    Oakes, Victoria; Furini, Simone; Pryde, David; Domene, Carmen

    2016-08-23

    Potassium channels in the two-pore domain family (K2P) have various structural attributes that differ from those of other K(+) channels, including a dimeric assembly constituted of nonidentical domains and an expansive extracellular cap. Crystallization of the prototypical K2P channel, TWIK-1, finally revealed the structure of these characteristics in atomic detail, allowing computational studies to be undertaken. In this study, we performed molecular-dynamics simulations for a cumulative time of ∼1 μs to discern the mechanism of ion transport throughout TWIK-1. We observed the free passage of ions beneath the extracellular cap and identified multiple high-occupancy sites in close proximity to charged residues on the protein surface. Despite the overall topological similarity of the x-ray structure of the selectivity filter to other K(+) channels, the structure diverges significantly in molecular-dynamics simulations as a consequence of nonconserved residues in both pore domains contributing to the selectivity filter (T118 and L228). The behavior of such residues has been linked to channel inactivation and the phenomenon of dynamic selectivity, where TWIK-1 displays robust Na(+) inward flux in response to subphysiological K(+) concentrations. PMID:27558721

  12. Mechanosensitive ion channels

    Directory of Open Access Journals (Sweden)

    Ken Takahashi

    2016-01-01

    Full Text Available Cell surface receptors are involved in numerous important biological processes including embryogenesis, tissue differentiation, and cellular homeostasis. Among them, mechanosensitive ion channels play an essential role in cellular functions of every cell including neurons, cardiomyocytes, and osteocytes. Here, we discuss types, roles, structures, and biophysical factors that affect the functions of mechanosensitive ion channels.

  13. RFI channels, 2

    Science.gov (United States)

    Mceliece, R. J.

    1981-01-01

    The cutoff parameters for a class of channel models exhibiting burst noise behavior were calculated and the performance of interleaved coding strategies was evaluated. It is concluded that, provided the channel memory is large enough and is properly exploited, interleaved coding is nearly optimal.

  14. Development of the BNFL Vitrified Residue Transport Flask

    International Nuclear Information System (INIS)

    The BNFL Vitrified Residue Flask has been designed by Nuclear Transport Limited (NTL), an associated company of BNFL. The body comprises a cylindrical shell and base manufactured from forged carbon manganese steel, with a stainless steel lid bolted to it. Silicon rubber neutron shielding is encapsulated in compartments at the flask ends and between the cooling fins. Removable shock absorbers are bolted to both ends, and two pairs of bolted trunnions are fitted for lifting and tie-down. The flask carries 21 vitrified residue containers in a support structure made up of 30 cast aluminium segments secured by a bolting system to the internal flask cavity. This assembled support structure forms seven circular channels to receive the vitrified residue containers. (J.P.N.)

  15. Growing Role of Retail in Distribution Channels

    OpenAIRE

    Ishak Mesic

    2011-01-01

    This article aims to demonstrate the growing role of retail trade (retail) in the channels of distribution of goods both in domestic and international markets. Technical-technological development has provided great opportunities for all production of material goods, so that the focus of problem in the economic possibilities of playing shifted from production to sales opportunities, or consumption. The ultimate consumers and their needs and requirements have become a central area of study, bas...

  16. Channelling versus inversion

    DEFF Research Database (Denmark)

    Gale, A.S.; Surlyk, Finn; Anderskouv, Kresten

    2013-01-01

    . Within this channel were smaller erosional structures (<10 m deep) that truncate originally horizontal bedding, are floored by hardgrounds, and locally have a basal fill of granular phosphorite. The entire channel system was progressively infilled by chalk, as demonstrated by the expanded succession of...... the lower Campanian Culver Chalk Formation. The beds of the channel fill are cut by small step faults, resulting from gravitational collapse. Complete burial had taken place by the base of the upper Campanian Portsdown Chalk Formation, which is of even thickness across the region. The structures are......Evidence from regional stratigraphical patterns in Santonian−Campanian chalk is used to infer the presence of a very broad channel system (5 km across) with a depth of at least 50 m, running NNW−SSE across the eastern Isle of Wight; only the western part of the channel wall and fill is exposed...

  17. Incompatibility breaking quantum channels

    International Nuclear Information System (INIS)

    A typical bipartite quantum protocol, such as EPR-steering, relies on two quantum features, entanglement of states and incompatibility of measurements. Noise can delete both of these quantum features. In this work we study the behavior of incompatibility under noisy quantum channels. The starting point for our investigation is the observation that compatible measurements cannot become incompatible by the action of any channel. We focus our attention to channels which completely destroy the incompatibility of various relevant sets of measurements. We call such channels incompatibility breaking, in analogy to the concept of entanglement breaking channels. This notion is relevant especially for the understanding of noise-robustness of the local measurement resources for steering. (paper)

  18. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...... drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate that...... they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K(+) channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure. The...

  19. Athermalized channeled spectropolarimeter enhancement.

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Julia Craven; Way, Brandyn Michael; Mercier, Jeffrey Alan; Hunt, Jeffery P.

    2013-09-01

    Channeled spectropolarimetry can measure the complete polarization state of light as a function of wavelength. Typically, a channeled spectropolarimeter uses high order retarders made of uniaxial crystal to amplitude modulate the measured spectrum with the spectrally-dependent Stokes polarization information. A primary limitation of conventional channeled spectropolarimeters is related to the thermal variability of the retarders. Thermal variation often forces frequent system recalibration, particularly for field deployed systems. However, implementing thermally stable retarders, made of biaxial crystal, results in an athermal channeled spectropolarimeter that relieves the need for frequent recalibration. This report presents experimental results for an anthermalized channeled spectropolarimeter prototype produced using potassium titanyl phosphate. The results of this prototype are compared to the current thermal stabilization state of the art. Finally, the application of the technique to the thermal infrared is studied, and the athermalization concept is applied to an infrared imaging spectropolarimeter design.

  20. Evaluation of residue-residue contact predictions in CASP9

    KAUST Repository

    Monastyrskyy, Bohdan

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures being the precision in recognizing contacts and the difference between the distribution of distances in the subset of predicted contact pairs versus all pairs of residues in the structure. The emphasis is placed on the prediction of long-range contacts (i.e., contacts between residues separated by at least 24 residues along sequence) in target proteins that cannot be easily modeled by homology. Although there is considerable activity in the field, the current analysis reports no discernable progress since CASP8.

  1. Measurement and analysis of cross-section for some residues produced in 16O + 27Al system

    International Nuclear Information System (INIS)

    In the present work, the theoretical estimate of the cross-section for the evaporation residues has been determined using code ALICE-91 which is based on statistical approach and considers the population of the residues only through CF channels, including PE emission

  2. EPICS channel access using websocket

    International Nuclear Information System (INIS)

    Web technology is useful as a means of widely disseminating accelerator and beam status information. For this purpose, WebOPI was implemented by SNS as a web-based system using Ajax (asynchronous JavaScript and XML) with EPICS. On the other hand, it is often necessary to control the accelerator from different locations as well as the central control room during beam operation and maintenance. However, it is not realistic to replace the GUI-based operator interface (OPI) with a Web-based system using Ajax technology because of interactive performance issue. Therefore, as a next generation OPI over the web using EPICS Channel Access (CA), we developed a client system based on WebSocket, which is a new protocol provided by the Internet Engineering Task Force (IETF) for Web-based systems. WebSocket is a web technology that provides bidirectional, full-duplex communication channels over a single TCP connection. By utilizing Node.js and the WebSocket access library called Socket.IO, a WebSocket server was implemented. Node.js is a server-side JavaScript language built on the Google V8 JavaScript Engine. In order to construct the WebSocket server as an EPICS CA client, an add-on for Node.js was developed in C/C++ using the EPICS CA library, which is included in the EPICS base. As a result, for accelerator operation, Web-based client systems became available not only in the central control room but also with various types of equipment. (author)

  3. On tide-induced lagrangian residual current and residual transport: 1. Lagrangian residual current

    Science.gov (United States)

    Feng, Shizuo; Cheng, Ralph T.; Pangen, Xi

    1986-01-01

    Residual currents in tidal estuaries and coastal embayments have been recognized as fundamental factors which affect the long-term transport processes. It has been pointed out by previous studies that it is more relevant to use a Lagrangian mean velocity than an Eulerian mean velocity to determine the movements of water masses. Under weakly nonlinear approximation, the parameter k, which is the ratio of the net displacement of a labeled water mass in one tidal cycle to the tidal excursion, is assumed to be small. Solutions for tides, tidal current, and residual current have been considered for two-dimensional, barotropic estuaries and coastal seas. Particular attention has been paid to the distinction between the Lagrangian and Eulerian residual currents. When k is small, the first-order Lagrangian residual is shown to be the sum of the Eulerian residual current and the Stokes drift. The Lagrangian residual drift velocity or the second-order Lagrangian residual current has been shown to be dependent on the phase of tidal current. The Lagrangian drift velocity is induced by nonlinear interactions between tides, tidal currents, and the first-order residual currents, and it takes the form of an ellipse on a hodograph plane. Several examples are given to further demonstrate the unique properties of the Lagrangian residual current.

  4. Energetics of ion competition in the DEKA selectivity filter of neuronal sodium channels

    OpenAIRE

    Boda, D.; Leaf, G.; Fonseca, J.; Eisenberg, B.

    2015-01-01

    The energetics of ionic selectivity in the neuronal sodium channels is studied. A simple model constructed for the selectivity filter of the channel is used. The selectivity filter of this channel type contains aspartate (D), glutamate (E), lysine (K), and alanine (A) residues (the DEKA locus). We use Grand Canonical Monte Carlo simulations to compute equilibrium binding selectivity in the selectivity filter and to obtain various terms of the excess chemical potential from a particle insertio...

  5. A study on the production of agricultural residues in Italy

    Energy Technology Data Exchange (ETDEWEB)

    Di Blasi, C.; Tanzi, V.; Lanzetta, M. [Universita degli Studi di Napoli Federico II, Dip di Ingegneria Chimica, Napoli (Italy)

    1997-12-01

    The Italian production of agricultural residues has been evaluated with a view to energy recovery through gasification. Two main categories of residues have been identified: the first, (A) is associated with the growing and collection of products with a nutritional value, whereas the second (B) includes the residues associated with the subsequent processing in order to obtain final products for commercialization. Category A, which comprises three further sub-categories: straw (A1); woody residues (A2); and stems and leaves (residues from vegetables, tobacco, sugar beet, (A3)), results in about 16.5 mt yr. The average amount of straw (A1) is 11 mt/yr, of which about 60% is waste to be eliminated. Woody residues (A2) (mainly pruning off-cuts from vineyards and olive groves) are about 3.5 mt/yr (85% unused). Category A3 amounts to about 2 mt/yr (90% unused). Straw is available mainly in the northern part of the country, whereas the other two sub-categories are widely distributed in central and southern regions. The yields of category B are estimated at 4 mt/yr, of which more than 3 mt/yr are waste products from grape and olive processing. Other residues, such as rice, sunflower and soya-bean husks (about 0.65 mt/yr), almond and nut shells and fruit stones (about 0.2 mt/yr), although not widely available on a national scale, can be significant on a local basis. The total amount of unused agricultural residues is about 14.5 mt/yr, which, if completely exploited through gasification, can contribute as much as 7-10% to the current national electricity needs. The regions of Veneto, Puglia, Friuli, Lombardia and Emilia Romagna appear to be good candidates for electricity production, given the significant surface concentration of unused residues (105-55 t km{sup 2}). (author)

  6. Landfilling of waste incineration residues

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi;

    2002-01-01

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling of...

  7. Ion channel screening.

    Science.gov (United States)

    Dunlop, John; Bowlby, Mark; Peri, Ravikumar; Tawa, Gregory; LaRocque, James; Soloveva, Veronica; Morin, John

    2008-08-01

    Ion channels are attractive targets for drug discovery with recent estimates indicating that voltage and ligand-gated channels account for the third and fourth largest gene families represented in company portfolios after the G protein coupled and nuclear hormone receptor families. A historical limitation on ion channel targeted drug discovery in the form of the extremely low throughput nature of the gold standard assay for assessing functional activity, patch clamp electrophysiology in mammalian cells, has been overcome by the implementation of multi-well plate format cell-based screening strategies for ion channels. These have taken advantage of various approaches to monitor ion flux or membrane potential using radioactive, non-radioactive, spectroscopic and fluorescence measurements and have significantly impacted both high-throughput screening and lead optimization efforts. In addition, major advances have been made in the development of automated electrophysiological platforms to increase capacity for cell-based screening using formats aimed at recapitulating the gold standard assay. This review addresses the options available for cell-based screening of ion channels with examples of their utility and presents case studies on the successful implementation of high-throughput screening campaigns for a ligand-gated ion channel using a fluorescent calcium indicator, and a voltage-gated ion channel using a fluorescent membrane potential sensitive dye. PMID:18694388

  8. Monoubiquitination modulating membrane trafficking of ROMK channel

    Institute of Scientific and Technical Information of China (English)

    Yun-longBAI; Xiao-yanZHAO; JingXIAO; XingYAN; Dao-hongLIN; Bao-fengYANG

    2005-01-01

    AIM To study the membrane trafficking modulation of ROMK1 channel by ubiquitination. METHODS we immunoprecipitated protein with ROMK antibody from rat renal cortex and outer medulla, and apply western blot with ubiquitin antibody to detect that ROMK protein is being ubiquitination under physiological condition in vivo. Furthermore, we used His-antibody and ubiquitin antibodies to recongnize proteins in the cotransfected HEK293 cells with hemagglutinin-ubiquitin and His- tagged ROMK1 constructs, respectively. After all intracellular lysine (Lys) residues of ROMK1 had been individually mutated to arginine (Arg), two -electrode voltage clamp was used to measure the ROMK1 channel activity in Xenopus oocytes. To detect the effect of ubiquitin on ROMK1, we used Western blotting technique to search the difference on total protein expression levelspus oocytes.

  9. Statistical inference on residual life

    CERN Document Server

    Jeong, Jong-Hyeon

    2014-01-01

    This is a monograph on the concept of residual life, which is an alternative summary measure of time-to-event data, or survival data. The mean residual life has been used for many years under the name of life expectancy, so it is a natural concept for summarizing survival or reliability data. It is also more interpretable than the popular hazard function, especially for communications between patients and physicians regarding the efficacy of a new drug in the medical field. This book reviews existing statistical methods to infer the residual life distribution. The review and comparison includes existing inference methods for mean and median, or quantile, residual life analysis through medical data examples. The concept of the residual life is also extended to competing risks analysis. The targeted audience includes biostatisticians, graduate students, and PhD (bio)statisticians. Knowledge in survival analysis at an introductory graduate level is advisable prior to reading this book.

  10. Residual stresses in welded structures

    International Nuclear Information System (INIS)

    The nature of residual stresses in welded structures is discussed in terms of their magnitude, directionality, spatial distribution, range and variability. The effects of the following factors on the residual stresses are considered: material properties, material manufacture, structural geometry, fabrication procedure, welding procedure, post-weld treatments and service conditions. Examples are given of residual stress distributions in plate butt welds, circumferential butt welds and weld cladding. These illustrate the different magnitudes and distributions of residual stress that can be found in different joint geometries, and demonstrate the effects of the mechanical, thermal and metallurgical properties of the constituent materials and the sensitivity of residual stresses to pass sequence and to the restraints applied during welding. Further examples for the common case of circumferential butt welds in pipes and pressure vessels are used to illustrate the extent of residual stresses as a function of distance from the weld and the effects of post-weld heat treatment. Measurements or analytical predictions of residual stresses are often subject to significant scatter or variability. This scatter may be due to systematic factors such as variability in measurement location or material properties, or to experimental error in measured data, erroneous assumptions in analytical modelling or unknown factors such as pre-existing residual stresses, inadequately documented welding or fabrication procedures or unrecorded local repairs. Improved prediction and reduction of uncertainty of residual stresses will require better recording of the whole manufacturing and service history of the welded structure and its component materials and better understanding and analysis of the many processes that may affect the residual stresses

  11. Sediment dynamics in an offshore tidal channel in the southern Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    Wen-fei NI; Ya-ping WANG; Xin-qing ZOU; Ji-cai ZHANG; Jian-hua GAO

    2014-01-01

    The geomorphology of the southern Yellow Sea (SYS) is characterized by offshore radial sand ridges (RSR). An offshore tidal channel (KSY Channel) is located perpendicular to the coast, comprised of a main and a tributary channel separated by a submarine sand ridge (KSY Sand Ridge) extending seaward. In order to investigate the interactions among water flow, sediment transport, and topography, current velocity and suspended sediment concentration (SSC) were observed at 11 anchor stations along KSY Channel in RSR during a spring tide cycle. High resolution bottom topography was also surveyed. Residual currents and tidally averaged suspended sediment fluxes were calculated and analyzed by using the decomposition method. Results suggested that the water currents became stronger landward but with asymmetrical current speed and temporal duration of flood and ebb tides. Residual currents showed landward water transport in the nearshore channel and a clockwise circulation around the KSY Sand Ridge. Tidally-averaged SSC also increased landward along the channel. The main mechanisms controlling SSC variations were resuspension and horizontal advection, with spatial and temporal variations in the channel, which also contributed to sediment redistribution between channels and sand ridges. Residual flow transport and the tidal pumping effect dominated the suspended sediment flux in the KSY Channel. The KSY Sand Ridge had a potential southward migration due to the interaction between water flow, sediment transport, and topography.

  12. Biomassa, decomposição e cobertura do solo ocasionada por resíduos culturais de três espécies vegetais na região centro-oeste do Brasil Biomass, decomposition and soil cover by residues of three plant species in central- western Brazil

    Directory of Open Access Journals (Sweden)

    Carlo Adriano Boer

    2008-04-01

    Full Text Available Com a crescente adoção da semeadura direta na região Centro-Oeste do Brasil, faz-se necessário maior conhecimento sobre as plantas de cobertura para produção de palha. O presente estudo teve como objetivo avaliar a produção de biomassa verde e seca, a percentagem de cobertura do solo, bem como a dinâmica da decomposição da palhada de três espécies de plantas de cobertura em safrinha: amaranto (Amaranthus cruentus L. BRS Alegria, milheto (Pennisetum glaucum L. var. ADR500 e capim-pé-de-galinha [Eleusine coracana (L. Gaertn.]. O trabalho foi conduzido em um Latossolo Vermelho distroférrico textura argilosa. O delineamento experimental utilizado foi o de blocos casualizados, no esquema de parcelas subdivididas no tempo, com quatro repetições. Nas parcelas foram alocadas as espécies, subdivididas em nove épocas de avaliação (0, 30, 60, 90, 120, 150, 180, 210 e 240 dias após dessecação química das espécies em estudo. Amostras proporcionais da biomassa seca de cada espécie foram acondicionadas em bolsas de decomposição, que foram dispostas sobre o solo, sendo coletadas a cada 30 dias e pesadas até 240 dias após a instalação, para avaliar a dinâmica de decomposição, após o manejo das plantas de cobertura. O milheto ADR500 e o capim-pé-de-galinha proporcionaram maior produção de biomassa verde e seca, maior cobertura do solo e menores taxas de decomposição da palhada, não diferindo entre si. O milheto ADR500 apresentou maior relação C/N, seguido pelo capim-pé-de-galinha e amaranto. Ajustaram-se, para a percentagem de cobertura do solo e a decomposição de palhadas com o tempo, os modelos sigmoidal e exponencial decrescente, respectivamente. O milheto ADR500 e o capim-pé-de-galinha apresentaram comportamentos semelhantes, não diferindo na comparação dos modelos de cobertura do solo e decomposição de palhadas.With the prevalence of no-till systems in Central-Western Brazil, a more in-depth knowledge

  13. Role of the sixth transmembrane segment of domain IV of the cockroach sodium channel in the action of sodium channel-blocker insecticides

    OpenAIRE

    Silver, Kristopher S.; Nomura, Yoshiko; Salgado, Vincent L.; Dong, Ke

    2009-01-01

    Sodium channel-blocker insecticides (SCBIs), such as indoxacarb and metaflumizone, are a new class of insecticides with a mechanism of action different from those of other insecticides that target sodium channels. SCBIs block sodium channels in a manner similar to local anesthetics (LA) such as lidocaine. Several residues, particularly F1579 and Y1586, in the sixth transmembrane segment (S6) of domain IV (IV) of rat Nav1.4 sodium channels are required for the action of LAs and SCBIs and may f...

  14. Channel Choice: A Literature Review

    DEFF Research Database (Denmark)

    Østergaard Madsen, Christian; Kræmmergaard, Pernille

    2015-01-01

    The channel choice branch of e-government studies citizens’ and businesses’ choice of channels for interacting with government, and how government organizations can integrate channels and migrate users towards the most cost-efficient channels. In spite of the valuable contributions offered no sys...... systematic overview exist of channel choice. We present a literature review of channel choice studies in government to citizen context identifying authors, countries, methods, concepts, units of analysis, and theories, and offer suggestionsfor future studies....

  15. MoCha : a framework for coordination using mobile channels

    OpenAIRE

    Arbab, Farhad; Boer, de, J.W.; Bonsangue, Marcello; Guillen Scholten, Juan

    2001-01-01

    In this paper we describe MoCha, an infrastructure for distributed communication and collaboration using mobile channels as its medium. Channels allow directed, anonymous, and peer-to-peer communication among entities, while mobility ensures that the structure of their connections can change over time in arbitrary ways. MoCha provides a distributed middle-ware designed for communication and collaboration without requiring central servers or fixed network infrastructures.

  16. Ion Channels in Obesity: Pathophysiology and Potential Therapeutic Targets

    OpenAIRE

    LUIZ HENRIQUE CÉSAR VASCONCELOS; IARA LEÃO LUNA DE SOUZA; LILIAN SOUSA PINHEIRO; BAGNÓLIA ARAÚJO DA SILVA

    2016-01-01

    Obesity is a multifactorial disease related to metabolic disorders and associated with genetic determinants. Currently, ion channels activity has been linked to many of these disorders, in addition to the central regulation of food intake, energetic balance, hormone release and response, as well as the adipocyte cell proliferation. Therefore, the objective of this work is to review the current knowledge about the influence of ion channels in obesity development. This review used different sou...

  17. Channelized Streams in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This draft dataset consists of all ditches or channelized pieces of stream that could be identified using three input datasets; namely the1:24,000 National...

  18. TRP channels: an overview

    DEFF Research Database (Denmark)

    Pedersen, Stine Falsig; Owsianik, Grzegorz; Nilius, Bernd

    2005-01-01

    plethora of data on the roles of TRPs in a variety of tissues and species, including mammals, insects, and yeast. The present review summarizes the most pertinent recent evidence regarding the structural and functional properties of TRP channels, focusing on the regulation and physiology of mammalian TRPs.......The TRP ("transient receptor potential") family of ion channels now comprises more than 30 cation channels, most of which are permeable for Ca2+, and some also for Mg2+. On the basis of sequence homology, the TRP family can be divided in seven main subfamilies: the TRPC ('Canonical') family, the...... TRPV ('Vanilloid') family, the TRPM ('Melastatin') family, the TRPP ('Polycystin') family, the TRPML ('Mucolipin') family, the TRPA ('Ankyrin') family, and the TRPN ('NOMPC') family. The cloning and characterization of members of this cation channel family has exploded during recent years, leading to a...

  19. 28-Channel rotary transformer

    Science.gov (United States)

    Mclyman, W. T.

    1981-01-01

    Transformer transmits power and digital data across rotating interface. Array has many parallel data channels, each with potential l megabaud data rate. Ferrite-cored transformers are spaced along rotor; airgap between them reduces crosstalk.

  20. Side-Channel Oscilloscope

    CERN Document Server

    Chaudhuri, Sumanta

    2011-01-01

    Side-Channel Analysis used for codebreaking could be used constructively as a probing tool for internal gates in integrated circuits. This paper outlines basic methods and mathematics for that purpose

  1. CHANNEL ESTIMATION TECHNIQUE

    DEFF Research Database (Denmark)

    2015-01-01

    A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over the communicat......A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over the...... communication channel. The method further includes determining a sequence of second coefficient estimates of the communication channel based on a decomposition of the first coefficient estimates in a dictionary matrix and a sparse vector of the second coefficient estimates, the dictionary matrix including...

  2. TRP channels in disease.

    Science.gov (United States)

    Jordt, S E; Ehrlich, B E

    2007-01-01

    The transient receptor potential (TRP) channels are a large family of proteins with six main subfamilies termed the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and TRPA (ankyrin) groups. The sheer number of different TRPs with distinct functions supports the statement that these channels are involved in a wide range of processes ranging from sensing of thermal and chemical signals to reloading intracellular stores after responding to an extracellular stimulus. Mutations in TRPs are linked to pathophysiology and specific diseases. An understanding of the role of TRPs in normal physiology is just beginning; the progression from mutations in TRPs to pathophysiology and disease will follow. In this review, we focus on two distinct aspects of TRP channel physiology, the role of TRP channels in intracellular Ca2+ homeostasis, and their role in the transduction of painful stimuli in sensory neurons. PMID:18193640

  3. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    - serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...... of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume......, controlled cell death and cellular migration. Volume regulatory mechanisms has long been in focus for regulating cellular proliferation and my thesis work have been focusing on the role of Cl- channels in proliferation with specific emphasis on ICl, swell. Pharmacological blockage of the ubiquitously...

  4. Sensing with Ion Channels

    CERN Document Server

    Martinac, Boris

    2008-01-01

    All living cells are able to detect and translate environmental stimuli into biologically meaningful signals. Sensations of touch, hearing, sight, taste, smell or pain are essential to the survival of all living organisms. The importance of sensory input for the existence of life thus justifies the effort made to understand its molecular origins. Sensing with Ion Channels focuses on ion channels as key molecules enabling biological systems to sense and process the physical and chemical stimuli that act upon cells in their living environment. Its aim is to serve as a reference to ion channel specialists and as a source of new information to non specialists who want to learn about the structural and functional diversity of ion channels and their role in sensory physiology.

  5. Chloride channels in stroke

    Institute of Scientific and Technical Information of China (English)

    Ya-ping ZHANG; Hao ZHANG; Dayue Darrel DUAN

    2013-01-01

    Vascular remodeling of cerebral arterioles,including proliferation,migration,and apoptosis of vascular smooth muscle cells (VSMCs),is the major cause of changes in the cross-sectional area and diameter of the arteries and sudden interruption of blood flow or hemorrhage in the brain,ie,stroke.Accumulating evidence strongly supports an important role for chloride (Clˉ) channels in vascular remodeling and stroke.At least three Clˉ channel genes are expressed in VSMCs:1) the TMEM16A (or Ano1),which may encode the calcium-activated Clˉ channels (CACCs); 2) the CLC-3 Clˉ channel and Clˉ/H+ antiporter,which is closely related to the volume-regulated Clˉ channels (VRCCs); and 3) the cystic fibrosis transmembrane conductance regulator (CFTR),which encodes the PKA-and PKC-activated Clˉ channels.Activation of the CACCs by agonist-induced increase in intracellular Ca2+ causes membrane depolarization,vasoconstriction,and inhibition of VSMC proliferation.Activation of VRCCs by cell volume increase or membrane stretch promotes the production of reactive oxygen species,induces proliferation and inhibits apoptosis of VSMCs.Activation of CFTR inhibits oxidative stress and may prevent the development of hypertension.In addition,Clˉ current mediated by gammaaminobutyric acid (GABA) receptor has also been implicated a role in ischemic neuron death.This review focuses on the functional roles of Clˉ channels in the development of stroke and provides a perspective on the future directions for research and the potential to develop Clˉ channels as new targets for the prevention and treatment of stroke.

  6. Identification Via Quantum Channels

    OpenAIRE

    Winter, Andreas

    2012-01-01

    We review the development of the quantum version of Ahlswede and Dueck's theory of identification via channels. As is often the case in quantum probability, there is not just one but several quantizations: we know at least two different concepts of identification of classical information via quantum channels, and three different identification capacities for quantum information. In the present summary overview we concentrate on conceptual points and open problems, referring the reader to the ...

  7. Quantum Feedback Channels

    OpenAIRE

    Bowen, Garry

    2002-01-01

    In Shannon information theory the capacity of a memoryless communication channel cannot be increased by the use of feedback. In quantum information theory the no-cloning theorem means that noiseless copying and feedback of quantum information cannot be achieved. In this paper, quantum feedback is defined as the unlimited use of a noiseless quantum channel from receiver to sender. Given such quantum feedback, it is shown to provide no increase in the entanglement--assisted capacities of a memo...

  8. Physics of Ion Channels

    OpenAIRE

    Kuyucak, Serdar; Bastug, Turgut

    2003-01-01

    We review the basic physics involved in transport of ions across membrane channels in cells. Electrochemical forces that control the diffusion of ions are discussed both from microscopic and macroscopic perspectives. A case is made for use of Brownian dynamics as the minimal phenomenological model that provides a bridge between experiments and more fundamental theoretical approaches. Application of Brownian and molecular dynamics methods to channels with known molecular structures is discussed.

  9. Chaos in quantum channels

    OpenAIRE

    Hosur, Pavan; Qi, Xiao-Liang; Roberts, Daniel; Yoshida, Beni(Institute for Quantum Information & Matter and Walter Burke Institute for Theoretical Physics, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125, U.S.A.)

    2016-01-01

    We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channe...

  10. Channeling in quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Du Marchie van Voorthuysen, E.H.; Smulders, P.J.M. (Vakgroep Nucleaire Vaste Stof Fysica, Univ. of Groningen (Netherlands)); Werkman, R.D. (Vakgroep Vaste Stof Fysica, Univ. of Groningen (Netherlands)); Boer, J.L. de; Smaalen, S. van (Lab. of Inorganic Chemistry, Univ. of Groningen (Netherlands))

    1992-02-01

    Ion-beam channeling has been observed in quasicrystals. For 1 MeV {sup 4}He{sup +} ions in icosahedral AlCuFe the maximum effect found is 36%. The full width at half maximum of the observed dips is 1.3deg. The effect persists up to great depths (>200 nm), thus showing a high degree of ordering in this phase. The channeling effect is sensitive to radiation damage. (orig.).

  11. Channeling in quasicrystals

    International Nuclear Information System (INIS)

    Ion-beam channeling has been observed in quasicrystals. For 1 MeV 4He+ ions in icosahedral AlCuFe the maximum effect found is 36%. The full width at half maximum of the observed dips is 1.3deg. The effect persists up to great depths (>200 nm), thus showing a high degree of ordering in this phase. The channeling effect is sensitive to radiation damage. (orig.)

  12. Structural elements in the Girk1 subunit that potentiate G protein-gated potassium channel activity.

    Science.gov (United States)

    Wydeven, Nicole; Young, Daniele; Mirkovic, Kelsey; Wickman, Kevin

    2012-12-26

    G protein-gated inwardly rectifying K(+) (Girk/K(IR)3) channels mediate the inhibitory effect of many neurotransmitters on excitable cells. Girk channels are tetramers consisting of various combinations of four mammalian Girk subunits (Girk1 to -4). Although Girk1 is unable to form functional homomeric channels, its presence in cardiac and neuronal channel complexes correlates with robust channel activity. This study sought to better understand the potentiating influence of Girk1, using the GABA(B) receptor and Girk1/Girk2 heteromer as a model system. Girk1 did not increase the protein levels or alter the trafficking of Girk2-containing channels to the cell surface in transfected cells or hippocampal neurons, indicating that its potentiating influence involves enhancement of channel activity. Structural elements in both the distal carboxyl-terminal domain and channel core were identified as key determinants of robust channel activity. In the distal carboxyl-terminal domain, residue Q404 was identified as a key determinant of receptor-induced channel activity. In the Girk1 core, three unique residues in the pore (P) loop (F137, A142, Y150) were identified as a collective potentiating influence on both receptor-dependent and receptor-independent channel activity, exerting their influence, at least in part, by enhancing mean open time and single-channel conductance. Interestingly, the potentiating influence of the Girk1 P-loop is tempered by residue F162 in the second membrane-spanning domain. Thus, discontinuous and sometime opposing elements in Girk1 underlie the Girk1-dependent potentiation of receptor-dependent and receptor-independent heteromeric channel activity. PMID:23236146

  13. Novel perspectives in cancer therapy: Targeting ion channels.

    Science.gov (United States)

    Arcangeli, Annarosa; Becchetti, Andrea

    2015-01-01

    By controlling ion fluxes at multiple time scales, ion channels shape rapid cell signals, such as action potential and synaptic transmission, as well as much slower processes, such as mitosis and cell migration. As is currently increasingly recognized, a variety of channel types are involved in cancer hallmarks, and regulate specific stages of neoplastic progression. Long-term in vitro work has established that inhibition of these ion channels impairs the growth of cancer cells. Recently, these studies have been followed up in vivo, hence revealing that ion channels constitute promising pharmacological targets in oncology. The channel proteins can be often accessed from the extracellular milieu, which allows use of lower drug doses and decrease untoward toxicity. However, because of the central physiological roles exerted by ion channels in excitable cells, other types of side effects may arise, the gravest of which is cardiac arrhythmia. A paradigmatic case is offered by Kv11.1 (hERG1) channels. HERG1 blockers attenuate the progression of both hematologic malignancies and solid tumors, but may also lead to the lengthening of the electrocardiographic QT interval, thus predisposing the patient to ventricular arrhythmias. These side effects can be avoided by specifically inhibiting the channel isoforms which are highly expressed in certain tumors, such as Kv11.1B and the neonatal forms of voltage-gated Na(+) channels. Preclinical studies are also being explored in breast and prostate cancer (targeting voltage-gated Na(+) channels), and gliomas (targeting CLC-3). Overall, the possible approaches to improve the efficacy and safety of ion channel targeting in oncology include: (1) the development of specific inhibitors for the channel subtypes expressed in specific tumors; (2) drug delivery into the tumor by using antibodies or nanotechnology-based approaches; (3) combination regimen therapy and (4) blocking specific conformational states of the ion channel. We believe

  14. Course on Ionic Channels

    CERN Document Server

    1986-01-01

    This book is based on a series of lectures for a course on ionic channels held in Santiago, Chile, on November 17-20, 1984. It is intended as a tutorial guide on the properties, function, modulation, and reconstitution of ionic channels, and it should be accessible to graduate students taking their first steps in this field. In the presentation there has been a deliberate emphasis on the spe­ cific methodologies used toward the understanding of the workings and function of channels. Thus, in the first section, we learn to "read" single­ channel records: how to interpret them in the theoretical frame of kinetic models, which information can be extracted from gating currents in re­ lation to the closing and opening processes, and how ion transport through an open channel can be explained in terms of fluctuating energy barriers. The importance of assessing unequivocally the origin and purity of mem­ brane preparations and the use of membrane vesicles and optical tech­ niques in the stUGY of ionic channels a...

  15. Central Pain Syndrome

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Central Pain Syndrome Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What is Central Pain Syndrome? Central pain syndrome is a neurological condition ...

  16. Drug Residues and Food Safety

    OpenAIRE

    Bagley, Clell V, DVM

    2001-01-01

    Complaints and demands from consumers concerning a product usually occur after an incident involving injury, illness or death. However, this was not the case with the Alar scare with apples and it is not the case with the concern for drug residues in food animal products. There has been no increase in drug residues; in fact the rate of violation has steadily decreased. Neither has there been any outbreaks of illness, allergic reactions, or deaths related to residues, nor has there been a decr...

  17. Ion Channels in Obesity: Pathophysiology and Potential Therapeutic Targets.

    Science.gov (United States)

    Vasconcelos, Luiz H C; Souza, Iara L L; Pinheiro, Lílian S; Silva, Bagnólia A

    2016-01-01

    Obesity is a multifactorial disease related to metabolic disorders and associated with genetic determinants. Currently, ion channels activity has been linked to many of these disorders, in addition to the central regulation of food intake, energetic balance, hormone release and response, as well as the adipocyte cell proliferation. Therefore, the objective of this work is to review the current knowledge about the influence of ion channels in obesity development. This review used different sources of literature (Google Scholar, PubMed, Scopus, and Web of Science) to assess the role of ion channels in the pathophysiology of obesity. Ion channels present diverse key functions, such as the maintenance of physiological homeostasis and cell proliferation. Cell biology and pharmacological experimental evidences demonstrate that proliferating cells exhibit ion channel expression, conductance, and electrical properties different from the resting cells. Thereby, a large variety of ion channels has been identified in the pathogenesis of obesity such as potassium, sodium, calcium and chloride channels, nicotinic acetylcholine receptor and transient receptor potential channels. The fundamental involvement of these channels on the generation of obesity leads to the progress in the knowledge about the mechanisms responsible for the obesity pathophysiology, consequently emerging as new targets for pharmacological modulation. PMID:27065858

  18. Ion Channels in Obesity: Pathophysiology and Potential Therapeutic Targets

    Directory of Open Access Journals (Sweden)

    LUIZ HENRIQUE CÉSAR VASCONCELOS

    2016-03-01

    Full Text Available Obesity is a multifactorial disease related to metabolic disorders and associated with genetic determinants. Currently, ion channels activity has been linked to many of these disorders, in addition to the central regulation of food intake, energetic balance, hormone release and response, as well as the adipocyte cell proliferation. Therefore, the objective of this work is to review the current knowledge about the influence of ion channels in obesity development. This review used different sources of literature (Google Scholar, PubMed, Scopus and Web of Science to assess the role of ion channels in the pathophysiology of obesity. Ion channels present diverse key functions, such as the maintenance of physiological homeostasis and cell proliferation. Cell biology and pharmacological experimental evidences demonstrate that proliferating cells exhibit ion channel expression, conductance and electrical properties different from the resting cells. Thereby, a large variety of ion channels has been identified in the pathogenesis of obesity such as potassium, sodium, calcium and chloride channels, nicotinic acetylcholine receptor and transient receptor potential channels. The fundamental involvement of these channels on the generation of obesity leads to the progress in the knowledge about the mechanisms responsible for the obesity pathophysiology, consequently emerging as new targets for pharmacological modulation.

  19. Morphodynamics of Floodplain Chute Channels

    Science.gov (United States)

    David, S. R.; Edmonds, D. A.

    2015-12-01

    Floodplain chute channel formation is a key process that can enable rivers to transition from single-thread to multi-thread planform geometries. Floodplain chute channels are usually incisional channels connecting topographic lows across point bars and in the floodplain. Surprisingly, it is still not clear what conditions promote chute channel formation and what governs their morphodynamic behavior. Towards this end we have initiated an empirical and theoretical study of floodplain chute channels in Indiana, USA. Using elevation models and satellite imagery we mapped 3064 km2 of floodplain in Indiana, and find that 37.3% of mapped floodplains in Indiana have extensive chute channel networks. These chute channel networks consist of two types of channel segments: meander cutoffs of the main channel and chute channels linking the cutoffs together. To understand how these chute channels link meander cutoffs together and eventually create floodplain channel networks we use Delft3D to explore floodplain morphodynamics. Our first modeling experiment starts from a generic floodplain prepopulated with meander cutoffs to test under what conditions chute channels form.We find that chute channel formation is optimized at an intermediate flood discharge. If the flood discharge is too large the meander cutoffs erosively diffuse, whereas if the floodwave is too small the cutoffs fill with sediment. A moderately sized floodwave reworks the sediment surrounding the topographic lows, enhancing the development of floodplain chute channels. Our second modeling experiments explore how floodplain chute channels evolve on the West Fork of the White River, Indiana, USA. We find that the floodplain chute channels are capable of conveying the entire 10 yr floodwave (Q=1330m3/s) leaving the inter-channel areas dry. Moreover, the chute channels can incise into the floodplain while the margins of channels are aggrading, creating levees. Our results suggest that under the right conditions

  20. Ion permeation of AQP6 water channel protein. Single channel recordings after Hg2+ activation.

    Science.gov (United States)

    Hazama, Akihiro; Kozono, David; Guggino, William B; Agre, Peter; Yasui, Masato

    2002-08-01

    Aquaporin-6 (AQP6) has recently been identified as an intracellular vesicle water channel with anion permeability that is activated by low pH or HgCl2. Here we present direct evidence of AQP6 channel gating using patch clamp techniques. Cell-attached patch recordings of AQP6 expressed in Xenopus laevis oocytes indicated that AQP6 is a gated channel with intermediate conductance (49 picosiemens in 100 mm NaCl) induced by 10 microm HgCl2. Current-voltage relationships were linear, and open probability was fairly constant at any given voltage, indicating that Hg2+-induced AQP6 conductance is voltage-independent. The excised outside-out patch recording revealed rapid activation of AQP6 channels immediately after application of 10 microm HgCl2. Reduction of both Na+ and Cl- concentrations from 100 to 30 mm did not shift the reversal potential of the Hg2+-induced AQP6 current, suggesting that Na+ is as permeable as Cl-. The Na+ permeability of Hg2+-induced AQP6 current was further demonstrated by 22Na+ influx measurements. Site-directed mutagenesis identified Cys-155 and Cys-190 residues as the sites of Hg2+ activation both for water permeability and ion conductance. The Hill coefficient from the concentration-response curve for Hg2+-induced conductance was 1.1 +/- 0.3. These data provide the first evidence of AQP6 channel gating at a single-channel level and suggest that each monomer contains the pore region for ions based on the number of Hg2+-binding sites and the kinetics of Hg2+-activation of the channel. PMID:12034750

  1. Investigation on Nodalization for Analysis of SFR Channel Blockage Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Won Pyo; Kwon, Young Min; Ha, Ki Suk; Lee, Kwi Lim; Jeong, Hae Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The present paper demonstrates nodalization analysis results obtained in application of the MATRA-LMR/FB to channel blockage accidents for a SFR (Sodium cooled Fast Reactor), KALIMER-150. In the earlier study, a uniform node size over the total sub-channel length in a subassembly was used. The study was carried out not only for the radially different positions, i.e. central, medium between the center and the duct wall, and edge sub-channels in the assembly, but also for larger blockage sizes larger than 6 sub-channels, the blockage size of which was classified into a DBE(Design Basis Event) in the KALIMER-150 design. The present investigation focuses mainly on the identification of conservatism as well as consistency in the analyses of the maximum coolant temperature for the 6 sub-channels blockage accidents

  2. A 256 channel digital filter for a data acquisition system

    International Nuclear Information System (INIS)

    The TRIUMF Central Control System (CCS) employs several data acquisition systems to monitor its operational parameters. Each system multiplexes 256 analog channels into one analog to digital converter. Space constraints on the multiplexer cards prohibit the installation of adequate anti-alias filters which allows 60 Hz and other noise to corrupt the measurements. The new system overcomes this problem by sampling each channel at a 160 samples/second rate and using a DSP microcomputer to lowpass filter the data. The multiplexer and analog-digital converter operate at 256 times the channel sample rate. The channel filter bandwidth is restricted to approximately 1 Hz due to the rate at which the CCS reads the data. One DSP microcomputer is able to filter the 256 channels in a multiplexed system at a cost less than that of the anti-alias filters which would otherwise have been required

  3. Maersk navigator oil spill in the great channel (Andaman Sea) in January 1993 and its environmental impact

    Digital Repository Service at National Institute of Oceanography (India)

    SenGupta, R.; Fondekar, S.P.; Shailaja, M.S.; Sankaranarayanan, V.N.

    Observations on oil slicks, tar residues and dissolved petroleum hydrocarbons (DPH) shortly after the oil spill resulting from the tanker accident in January 1993 showed negligible impact on the Indian EEZ of the Great Channel (Andaman Sea). DPH...

  4. Propoxur residues in cocoa beans

    International Nuclear Information System (INIS)

    Pod-bearing Amazon and Amelonado cocoa plants were sprayed with Unden 20% (propoxur, arprocarb, baygon) at the recommended rate of 210 g a.i./ha and twice the recommended rate at monthly intervals from July to October, 1976, and cured beans from the ripe pods analysed for propoxur residues by gas chromatography. In a radiotracer study with 14C-labelled propoxur, the effect of processing methods on residues and systemic uptake of propoxur from insecticide deposits on pod surfaces were also investigated. Residues did not exceed 0.03 ppm. There was no relationship between residues and harvesting time, cocoa type or rate of application. Contamination of beans with insecticide deposits on the pod surface during processing, and systemic uptake of insecticide from pod surfaces were negligible. (author)

  5. Nitrogen availability of biogas residues

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Fouda, Sara

    2011-09-07

    The objectives of this study were to characterize biogas residues either unseparated or separated into a liquid and a solid phase from the fermentation of different substrates with respect to their N and C content. In addition, short and long term effects of the application of these biogas residues on the N availability and N utilization by ryegrass was investigated. It is concluded that unseparated or liquid separated biogas residues provide N at least corresponding to their ammonium content and that after the first fertilizer application the C{sub org}:N{sub org} ratio of the biogas residues was a crucial factor for the N availability. After long term application, the organic N accumulated in the soil leads to an increased release of N.

  6. Landfilling of waste incineration residues

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi; Chen, D.

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling of...... the ashes. Leaching test, however, must be selected carefully to provide information relevant for the actual disposal scenario and for evaluating the benefits of pre-treating the residues prior to landfilling. This paper describes research at the Technical University of Denmark addressing some of...... these issues focusing on pH-development in landfilled residues, effects of leaching test conditions on Cr leaching and effects of pre-treatment with FeSO4....

  7. Americium recovery from reduction residues

    Science.gov (United States)

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  8. Corporate law and Residual Claimants

    OpenAIRE

    Black, Bernard

    1999-01-01

    Common shareholders are not the only important residual claimants on a firm's income. Instead, other claimants, including employees, creditors, preferred shareholders, option holders, suppliers, customers, and the government (as tax collector) also often gain substatially when the firm does well, and suffer when the firm does badly. The conventional contractarian explanation for why only common shareholders vote - that they are the firm's principal residual claima...

  9. Parshin residues via coboundary operators

    OpenAIRE

    Mazin, Mikhail

    2012-01-01

    The article consist of two main parts: an analog of the Leray Theory for Singular Varieties and its application to the Theory of Parshin's Residues. The first part is independent from the second. It uses the theory of Whitney stratifications. The second part is an application of the first. In particular, a geometric and very transparent proof of the Parshin's Reciprocity Law for residues is given.

  10. Coordination Mechanisms Based on Strategic Innovative Compensation in Dual-Channel Supply Chains%考虑创新补偿的双渠道供应链协调机制研究

    Institute of Scientific and Technical Information of China (English)

    陈树桢; 熊中楷; 李根道; 文海鸿

    2011-01-01

    movement of retailers. We also analyze and compare strategic movements of manufacturers and retailers.In the first part, we study and compare two business cases between a decentralized manufacturer using innovative compensation strategy, and another manufacturer not using this strategy. These two case studies show that the faster the initial distribution cost of the retailer channel declines, the higher the optimal level of investment that a manufacturer is more willing to compensate for its retailer's innovative compensation. A manufacturer will increase its wholesale price and keep the online channel price as before to balance the investment cost of retailers. A retailer will increase investment in channel innovation and reduce its retail price at the same time. Both manufacturers and retailers can benefit from a manufacturer's compensation investment. In addition, we discuss and compare innovative compensation investment under centralized and decentralize decision-making processes. In the centralized decision making process, the retailer price is always the lowest when the online price remains the same. This finding is contrary to our expectations. With the decentralized decision-making process, the entire supply chain always has the highest profit and manufacturers have the highest investment in innovation activities. With the decentralized decision making process, a manufacturer has an incentive to design mechanisms to coordinate with retailers to benefit both parties.In the second part, we examine ways to adjust manufacturer-retailer relationships using two-part tariffs. Some cases show that twopart tariffs can coordinate traditional channels by turning a retailer into a “residual claimant” of channel profits. However, the “residual clamant” mechanism breaks down in the dual-channel model. Unexpectedly, two-part tariffs can coordinate the dual-channel model and a manufacturer can effectively set its wholesale price and fix fees at the right level. At the same

  11. Improvment of wood-residues conversion technology

    OpenAIRE

    Posharnikov, Feliks; Bazarskaya, Nina; Bulanov, Aleksandr

    2011-01-01

    The problem of wood residues conversion is considered. The sizes-based types of wood residues and results of wood residues conversion are presented. Sawdust-based-cement a new original product is offered

  12. The residual strength of a ship after an internal explosion

    OpenAIRE

    Surko, Stephen William

    1988-01-01

    CIVINS An internal airblast from a missile explosion produces tearing, holing and dishing of ship's structural plating. In order to analyze the residual strength of a ship after an internal explosion, a typical ship compartment was considered to be composed of flat square plates subjected to uniaxial compression, and the damage effects were examined independently. The holing was considered to be a centrally located circle. Plastic limit load analysis of a flat plate indicates that ultimate...

  13. Mitochondrial Ion Channels

    Science.gov (United States)

    O’Rourke, Brian

    2009-01-01

    In work spanning more than a century, mitochondria have been recognized for their multifunctional roles in metabolism, energy transduction, ion transport, inheritance, signaling, and cell death. Foremost among these tasks is the continuous production of ATP through oxidative phosphorylation, which requires a large electrochemical driving force for protons across the mitochondrial inner membrane. This process requires a membrane with relatively low permeability to ions to minimize energy dissipation. However, a wealth of evidence now indicates that both selective and nonselective ion channels are present in the mitochondrial inner membrane, along with several known channels on the outer membrane. Some of these channels are active under physiological conditions, and others may be activated under pathophysiological conditions to act as the major determinants of cell life and death. This review summarizes research on mitochondrial ion channels and efforts to identify their molecular correlates. Except in a few cases, our understanding of the structure of mitochondrial ion channels is limited, indicating the need for focused discovery in this area. PMID:17059356

  14. MEMS in microfluidic channels.

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol Iris Hill; Okandan, Murat; Michalske, Terry A.; Sounart, Thomas L.; Matzke, Carolyn M.

    2004-03-01

    Microelectromechanical systems (MEMS) comprise a new class of devices that include various forms of sensors and actuators. Recent studies have shown that microscale cantilever structures are able to detect a wide range of chemicals, biomolecules or even single bacterial cells. In this approach, cantilever deflection replaces optical fluorescence detection thereby eliminating complex chemical tagging steps that are difficult to achieve with chip-based architectures. A key challenge to utilizing this new detection scheme is the incorporation of functionalized MEMS structures within complex microfluidic channel architectures. The ability to accomplish this integration is currently limited by the processing approaches used to seal lids on pre-etched microfluidic channels. This report describes Sandia's first construction of MEMS instrumented microfluidic chips, which were fabricated by combining our leading capabilities in MEMS processing with our low-temperature photolithographic method for fabricating microfluidic channels. We have explored in-situ cantilevers and other similar passive MEMS devices as a new approach to directly sense fluid transport, and have successfully monitored local flow rates and viscosities within microfluidic channels. Actuated MEMS structures have also been incorporated into microfluidic channels, and the electrical requirements for actuation in liquids have been quantified with an elegant theory. Electrostatic actuation in water has been accomplished, and a novel technique for monitoring local electrical conductivities has been invented.

  15. Acid-sensing ion channels and migraine

    Directory of Open Access Journals (Sweden)

    Yu-qi KANG

    2015-09-01

    Full Text Available Acid-sensing ion channels (ASICs are ligand-gated ion channels that are activated by extracellular protons (H+, which belong to epithelial sodium channels/degenerin (ENaC/DEG superfamily. ASICs are widely distributed in central nervous system, peripheral nervous system, digestive system and some tumor tissues. Different ASIC subunits play important roles in various pathophysiological processes such as touch, sour taste, learning and memory, including inflammation, ischemic stroke, pain, learning and memory decline, epilepsy, multiple sclerosis (MS, migraine, irritable bowel syndrome and tumor. Research over the last 2 decades has achieved substantial advances in migraine pathophysiology. It is now largely accepted that inflammatory pathways play a key role and three main events seem to take place: cortical spreading depression (CSD, activation of the trigeminovascular system (i.e. dural nociceptors, peripheral and central sensitization of this pain pathway. However, the exact mechanisms that link these three events to each other and to inflammation have so far remained to be studied. This article takes an overview of newly research advances in structure, distribution and the relationship with migraine of ASICs.  DOI: 10.3969/j.issn.1672-6731.2015.09.013

  16. Residual stress measurement of the jacket material for ITER coil by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Nickel-Iron based super alloy INCOLOY 908 is used for the jacket of a central solenoid coil (CS coil) of the International Thermonuclear Experimental Reactor (ITER). INCOLOY 908, however, has a possibility of fracture due to Stress Accelerated Grain Boundary Oxidation (SAGBO) under a tensile residual stress beyond 200MPa. Therefore it is necessary to measure the residual stress of the jacket to avoid SAGBO. We performed residual stress measurement of the jacket by neutron diffraction using the neutron diffractometer for residual stress analysis (RESA) installed at JRR-3M in JAERI. A sample depth dependence of internal strain was obtained from the (111) plane spacing. A residual stress distribution was calculated from the strain using Young`s modulus and Poisson`s ratio that were evaluated by a tensile test with neutron diffraction. The result shows that the tensile residual stress exceeds 200MPa of the SAGBO condition in some regions inside the jacket. (author)

  17. Breathing Stimulant Compounds Inhibit TASK-3 Potassium Channel Function Likely by Binding at a Common Site in the Channel Pore.

    Science.gov (United States)

    Chokshi, Rikki H; Larsen, Aaron T; Bhayana, Brijesh; Cotten, Joseph F

    2015-11-01

    Compounds PKTHPP (1-{1-[6-(biphenyl-4-ylcarbonyl)-5,6,7,8-tetrahydropyrido[4,3-d]-pyrimidin-4-yl]piperidin-4-yl}propan-1-one), A1899 (2''-[(4-methoxybenzoylamino)methyl]biphenyl-2-carboxylic acid 2,4-difluorobenzylamide), and doxapram inhibit TASK-1 (KCNK3) and TASK-3 (KCNK9) tandem pore (K2P) potassium channel function and stimulate breathing. To better understand the molecular mechanism(s) of action of these drugs, we undertook studies to identify amino acid residues in the TASK-3 protein that mediate this inhibition. Guided by homology modeling and molecular docking, we hypothesized that PKTHPP and A1899 bind in the TASK-3 intracellular pore. To test our hypothesis, we mutated each residue in or near the predicted PKTHPP and A1899 binding site (residues 118-128 and 228-248), individually, to a negatively charged aspartate. We quantified each mutation's effect on TASK-3 potassium channel concentration response to PKTHPP. Studies were conducted on TASK-3 transiently expressed in Fischer rat thyroid epithelial monolayers; channel function was measured in an Ussing chamber. TASK-3 pore mutations at residues 122 (L122D, E, or K) and 236 (G236D) caused the IC50 of PKTHPP to increase more than 1000-fold. TASK-3 mutants L122D, G236D, L239D, and V242D were resistant to block by PKTHPP, A1899, and doxapram. Our data are consistent with a model in which breathing stimulant compounds PKTHPP, A1899, and doxapram inhibit TASK-3 function by binding at a common site within the channel intracellular pore region, although binding outside the channel pore cannot yet be excluded. PMID:26268529

  18. Evaluation of residue-residue contact prediction in CASP10

    KAUST Repository

    Monastyrskyy, Bohdan

    2013-08-31

    We present the results of the assessment of the intramolecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect interdomain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9.

  19. To centralize or not to centralize?

    OpenAIRE

    Campbell, Andrew; Kunisch, Sven; Müller-Stewens, Günter

    2011-01-01

    The CEO's dilemma-were the gains of centralization worth the pain it could cause?-is a perennial one. Business leaders dating back at least to Alfred Sloan, who laid out GM's influential philosophy of decentralization in a series of memos during the 1920s, have recognized that badly judged centralization can stifle initiative, constrain the ability to tailor products and services locally, and burden business divisions with high costs and poor service.1 Insufficient centralization can deny bus...

  20. Impacts of maintenance channel dredging in a northern Adriatic coastal lagoon. II: Effects on macrobenthic assemblages in channels and ponds

    Science.gov (United States)

    Ponti, Massimo; Pasteris, Andrea; Guerra, Roberta; Abbiati, Marco

    2009-10-01

    Coastal lagoons are ephemeral habitats whose conservation requires human intervention, such as maintenance dredging of inner channels. Dredging can reduce the abundance of benthic species due to the removal of individuals with the sediment, modify sediment properties, and resuspend fine sediment, nutrients and pollutants, which can lead to eutrophication, hypoxic events and increasing toxicity. Both direct effects in the dredged channel and possible indirect effects in surrounding shallow areas could be expected. This study assesses the effects of the channel maintenance dredging, performed between October 2004 and August 2005, on the invertebrate assemblages both in channels and adjacent ponds in the northern Adriatic coastal lagoon of Pialassa Baiona. The lagoon is affected by eutrophication, chemical and thermal pollution from wastewater treatment and power plants. Three impacted sites were located in the dredged channel and three in the adjacent interconnected shallow water ponds, while three non-impacted sites were located in a channel and in a pond far from the dredged area. Replicate samples were collected from each site one time before and one time after the dredging operations. Despite the extent of the intervention, effects of the dredging on macrobenthic assemblages were detected only within the dredged channel, while in the surrounding ponds no clear and unequivocal effects were found. In particular the dredging could have promoted the increase of the abundance of the polychaete Streblospio shrubsolii in the southern and central parts of the dredged channel and the increase in abundance of the amphipod Corophium insidiosum in the northern side, compared to the controls. Instead, species diversity was reduced in the central and northern parts of the dredged channel. These effects on the macrobenthic invertebrate assemblages could be related to the observed changes of sediment characteristics, contamination and toxicity. Overall, direct effects on benthic

  1. The sting. Melittin forms channels in lipid bilayers.

    OpenAIRE

    Tosteson, M T; Tosteson, D. C.

    1981-01-01

    Melittin, a toxin of bee venom, is a cationic polypeptide composed of 26 amino acids. The six residues of the C-terminal end are polar and 19 of the 20 residues of the N-terminal end are hydrophobic. Exposure of the lecithin bilayer to melittin results in the formation of channels that are more permeable to anions that to cations. Unilateral addition of melittin produces a voltage-dependent increase in membrane conductance when the side where the polypeptide is present in made positive but no...

  2. Zinc as Allosteric Ion Channel Modulator: Ionotropic Receptors as Metalloproteins.

    Science.gov (United States)

    Peralta, Francisco Andrés; Huidobro-Toro, Juan Pablo

    2016-01-01

    Zinc is an essential metal to life. This transition metal is a structural component of many proteins and is actively involved in the catalytic activity of cell enzymes. In either case, these zinc-containing proteins are metalloproteins. However, the amino acid residues that serve as ligands for metal coordination are not necessarily the same in structural proteins compared to enzymes. While crystals of structural proteins that bind zinc reveal a higher preference for cysteine sulfhydryls rather than histidine imidazole rings, catalytic enzymes reveal the opposite, i.e., a greater preference for the histidines over cysteines for catalysis, plus the influence of carboxylic acids. Based on this paradigm, we reviewed the putative ligands of zinc in ionotropic receptors, where zinc has been described as an allosteric modulator of channel receptors. Although these receptors do not strictly qualify as metalloproteins since they do not normally bind zinc in structural domains, they do transitorily bind zinc at allosteric sites, modifying transiently the receptor channel's ion permeability. The present contribution summarizes current information showing that zinc allosteric modulation of receptor channels occurs by the preferential metal coordination to imidazole rings as well as to the sulfhydryl groups of cysteine in addition to the carboxyl group of acid residues, as with enzymes and catalysis. It is remarkable that most channels, either voltage-sensitive or transmitter-gated receptor channels, are susceptible to zinc modulation either as positive or negative regulators. PMID:27384555

  3. Dequantization Via Quantum Channels

    Science.gov (United States)

    Andersson, Andreas

    2016-08-01

    For a unital completely positive map {Φ} ("quantum channel") governing the time propagation of a quantum system, the Stinespring representation gives an enlarged system evolving unitarily. We argue that the Stinespring representations of each power {Φ^m} of the single map together encode the structure of the original quantum channel and provide an interaction-dependent model for the bath. The same bath model gives a "classical limit" at infinite time {mto∞} in the form of a noncommutative "manifold" determined by the channel. In this way, a simplified analysis of the system can be performed by making the large-m approximation. These constructions are based on a noncommutative generalization of Berezin quantization. The latter is shown to involve very fundamental aspects of quantum-information theory, which are thereby put in a completely new light.

  4. Chaos in quantum channels

    CERN Document Server

    Hosur, Pavan; Roberts, Daniel A; Yoshida, Beni

    2015-01-01

    We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back up our results with numerics in two non-integrable models and analytic results in a perfect tensor network model of chaotic time evolution. These results show that the butterfly effect in quantum systems implies the information-theoretic definition of scrambling.

  5. Trp channels and itch.

    Science.gov (United States)

    Sun, Shuohao; Dong, Xinzhong

    2016-05-01

    Itch is a unique sensation associated with the scratch reflex. Although the scratch reflex plays a protective role in daily life by removing irritants, chronic itch remains a clinical challenge. Despite urgent clinical need, itch has received relatively little research attention and its mechanisms have remained poorly understood until recently. The goal of the present review is to summarize our current understanding of the mechanisms of acute as well as chronic itch and classifications of the primary itch populations in relationship to transient receptor potential (Trp) channels, which play pivotal roles in multiple somatosensations. The convergent involvement of Trp channels in diverse itch signaling pathways suggests that Trp channels may serve as promising targets for chronic itch treatments. PMID:26385480

  6. QKD Quantum Channel Authentication

    CERN Document Server

    Kosloski, J T

    2006-01-01

    Several simple yet secure protocols to authenticate the quantum channel of various QKD schemes, by coupling the photon sender's knowledge of a shared secret and the QBER Bob observes, are presented. It is shown that Alice can encrypt certain portions of the information needed for the QKD protocols, using a sequence whose security is based on computational-complexity, without compromising all of the sequence's entropy. It is then shown that after a Man-in-the-Middle attack on the quantum and classical channels, there is still enough entropy left in the sequence for Bob to detect the presence of Eve by monitoring the QBER. Finally, it is shown that the principles presented can be implemented to authenticate the quantum channel associated with any type of QKD scheme, and they can also be used for Alice to authenticate Bob.

  7. Aspartame affects the electrical activity of projection neurons in central nervous system by inhibiting the calcium channel current in Drosophila%阿斯巴甜抑制钙通道电流影响果蝇中枢投射神经元电活动

    Institute of Scientific and Technical Information of China (English)

    王琦; 齐旻悦; 吴诗哲; 顾怀宇

    2016-01-01

    目的:从突触水平检验不同浓度的阿斯巴甜对果蝇中枢神经元影响及作用机制,为进一步探究阿斯巴甜生物安全性提供支持。方法采用膜片钳全细胞记录的方法,通过离子通道的阻断与分离,分别记录给药前后果蝇投射神经元(PN)的胆碱能突触微小兴奋性电流(mEPSC)、钙离子通道电流和钙通道瞬时电流密度,统计并分析mEPSC幅值和频率,以及钙通道电流峰值和瞬时电流密度。结果与给药前相比,8μg/ml阿斯巴甜会降低果蝇PN的mEPSC频率(t=22.05,P<0.01)、钙电流峰值(t=5.01,P<0.01)和瞬时电流密度(t=2.68,P<0.05);2μg/ml阿斯巴甜会降低果蝇PN的mEPSC频率(t=3.15,P<0.05),其他实验指标差异则无统计学意义(P>0.05)。结论一定浓度的阿斯巴甜可影响果蝇中枢投射神经元的电活动,并且该作用可能是通过影响钙电流而实现的。%Objective To study the effect of different concentrations of aspartame in Drosophila central nervous system , especially to the electrical activity of projection neuron (PN), and evaluate the biological security of aspartame and neural mechanism. Methods The whole-cell electrophysiological signals of projection neurons in Drosophila was detected by patch clamp. The recordings of mini excitatory postsynaptic currents (mEPSC) and calcium currents were performed in both pre-and post-of aspartame treatment. Results Aspartame treatments with 8 μg/ml could reduce the frequency of mEPSC (t=22.05, P0.05) at the same time. In addition, there have no statistically significant in aspartame treatments with 2μg/ml experimental groups except for the frequency of mEPSC (t=3.15, P<0.05). Conclusion There has a range of aspartame concentration can significantly affect the electrical activity of projection neurons in Drosophila central nervous system, which could be effective via the calcium

  8. The neutron channeling phenomenon.

    Science.gov (United States)

    Khanouchi, A; Sabir, A; Boulkheir, M; Ichaoui, R; Ghassoun, J; Jehouani, A

    1997-01-01

    Shields, used for protection against radiation, are often pierced with vacuum channels for passing cables and other instruments for measurements. The neutron transmission through these shields is an unavoidable phenomenon. In this work we study and discuss the effect of channels on neutron transmission through shields. We consider an infinite homogeneous slab, with a fixed thickness (20 lambda, with lambda the mean free path of the neutron in the slab), which contains a vacuum channel. This slab is irradiated with an infinite source of neutrons on the left side and on the other side (right side) many detectors with windows equal to 2 lambda are placed in order to evaluate the neutron transmission probabilities (Khanouchi, A., Aboubekr, A., Ghassoun, J. and Jehouani, A. (1994) Rencontre Nationale des Jeunes Chercheurs en Physique. Casa Blanca Maroc; Khanouchi, A., Sabir, A., Ghassoun, J. and Jehouani, A. (1995) Premier Congré International des Intéractions Rayonnements Matière. Eljadida Maroc). The neutron history within the slab is simulated by the Monte Carlo method (Booth, T. E. and Hendricks, J. S. (1994) Nuclear Technology 5) and using the exponential biasing technique in order to improve the Monte Carlo calculation (Levitt, L. B. (1968) Nuclear Science and Engineering 31, 500-504; Jehouani, A., Ghassoun, J. and Aboubker, A. (1994) In Proceedings of the 6th International Symposium on Radiation Physics, Rabat, Morocco). Then different geometries of the vacuum channel have been studied. For each geometry we have determined the detector response and calculated the neutron transmission probability for different detector positions. This neutron transmission probability presents a peak for the detectors placed in front of the vacuum channel. This study allowed us to clearly identify the neutron channeling phenomenon. One application of our study is to detect vacuum defects in materials. PMID:9463884

  9. The earliest ion channels in protocellular membranes

    Science.gov (United States)

    Mijajlovic, Milan; Pohorille, Andrew; Wilson, Michael; Wei, Chenyu

    Cellular membranes with their hydrophobic interior are virtually impermeable to ions. Bulk of ion transport through them is enabled through ion channels. Ion channels of contemporary cells are complex protein molecules which span the membrane creating a cylindrical pore filled with water. Protocells, which are widely regarded as precursors to modern cells, had similarly impermeable membranes, but the set of proteins in their disposal was much simpler and more limited. We have been, therefore, exploring an idea that the first ion channels in protocellular membranes were formed by much smaller peptide molecules that could spontaneously self-assemble into short-lived cylindrical bundles in a membrane. Earlier studies have shown that a group of peptides known as peptaibols is capable of forming ion channels in lipid bilayers when they are exposed to an electric field. Peptaibols are small, non-genetically encoded peptides produced by some fungi as a part of their system of defense against bacteria. They are usually only 14-20 residues long, which is just enough to span the membrane. Their sequence is characterized by the presence of non-standard amino acids which, interestingly, are also expected to have existed on the early earth. In particular, the presence of 2-aminoisobutyric acid (AIB) gives peptaibols strong helix forming propensities. Association of the helices inside membranes leads to the formation of cylindrical bundles, typically containing 4 to 10 monomers. Although peptaibols are excellent candidates for models of the earliest ion channels their struc-tures, which are stabilized only by van der Waals forces and occasional hydrogen bonds between neighboring helices, are not very stable. Although it might properly reflect protobiological real-ity, it is also a major obstacle in studying channel behavior. For this reason we focused on two members of the peptaibol family, trichotoxin and antiamoebin, which are characterized by a single conductance level. This

  10. BLIND CHANNEL ESTIMATION IN DELAY DIVERSITY FOR FREQUENCY SELECTIVE CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Zhao Zheng; Jia Ying; Yin Qinye

    2003-01-01

    Delay diversity is an effective transmit diversity technique to combat adverse ef-fects of fading. Thus far, previous work in delay diversity assumed that perfect estimates ofcurrent channel fading conditions are available at the receiver and training symbols are requiredto estimate the channel from the transmitter to the receiver. However, increasing the number ofthe antennas increases the required training interval and reduces the available time within whichdata may be transmitted. Learning the channel coefficients becomes increasingly difficult for thefrequency selective channels. In this paper, with the subspace method and the delay character ofdelay diversity, a channel estimation method is proposed, which does not use training symbols. Itaddresses the transmit diversity for a frequency selective channel from a single carrier perspectivein the form of a simple equivalent fiat fading model. Monte Carlo simulations give the perfor-mance of channel estimation and the performance comparison of our channel-estimation-baseddetector with decision feedback equalization, which uses the perfect channel information.

  11. Transmembrane dynamics of the Thr-5 phosphorylated sarcolipin pentameric channel.

    Science.gov (United States)

    Cao, Yipeng; Wu, Xue; Wang, Xinyu; Sun, Haiying; Lee, Imshik

    2016-08-15

    Sarcolipin (SLN), an important membrane protein expressed in the sarcoplasmic reticulum (SR), regulates muscle contractions in cardiac and skeletal muscle. The phosphorylation at amino acid Thr5 of the SLN protein modulates the amount of Ca(2+) that passes through the SR. Using molecular dynamics simulation, we evaluated the phosphorylation at Thr5 of pentameric SLN (phospho-SLN) channel's energy barrier and pore characteristics by calculating the potential of mean force (PMF) along the channel pore and determining the diffusion coefficient. The results indicate that pentameric phospho-SLN promotes penetration of monovalent and divalent ions through the channel. The analysis of PMF, pore radius and diffusion coefficient indicates that Leu21 is the hydrophobic gate of the pentameric SLN channel. In the channel, water molecules near the Leu21 pore demonstrated a clear hydrated-dehydrated transition; however, the mutation of Leu21 to an Alanine (L21A) destroyed the hydrated-dehydrated transitions. These water-dynamic behaviors and PMF confirm that Leu21 is the key residue that regulates the ion permeability of the pentameric SLN channel. These results provide the structural-basis insights and molecular-dynamic information that are needed to understand the regulatory mechanisms of ion permeability in the pentameric SLN channel. PMID:27378083

  12. Lossy Joint Source-Channel Coding Using Raptor Codes

    Directory of Open Access Journals (Sweden)

    H. V. Poor

    2008-09-01

    Full Text Available The straightforward application of Shannon's separation principle may entail a significant suboptimality in practical systems with limited coding delay and complexity. This is particularly evident when the lossy source code is based on entropy-coded quantization. In fact, it is well known that entropy coding is not robust to residual channel errors. In this paper, a joint source-channel coding scheme is advocated that combines the advantages and simplicity of entropy-coded quantization with the robustness of linear codes. The idea is to combine entropy coding and channel coding into a single linear encoding stage. If the channel is symmetric, the scheme can asymptotically achieve the optimal rate-distortion limit. However, its advantages are more clearly evident under finite coding delay and complexity. The sequence of quantization indices is decomposed into bitplanes, and each bitplane is independently mapped onto a sequence of channel coded symbols. The coding rate of each bitplane is chosen according to the bitplane conditional entropy rate. The use of systematic raptor encoders is proposed, in order to obtain a continuum of coding rates with a single basic encoding algorithm. Simulations show that the proposed scheme can outperform the separated baseline scheme for finite coding length and comparable complexity and, as expected, it is much more robust to channel errors in the case of channel capacity mismatch.

  13. Fuel channel refilling

    International Nuclear Information System (INIS)

    Analysis of existing data on fuel channel refilling is presented. The analysis focuses on the data obtained using the Stern Laboratories Cold Water Injection Test (CWIT) Facility. The two-fluid model thermal-hydraulics computer code CATHENA is also used to simulate experimental results on fuel channel refilling from both the CWIT and RD-14 facilities. Conclusions related to single and double break tests, including the effect of non-condensible gases, are presented. A set of recommendations is given for further analysis and separate effect experiments. (67 figs., 5 tabs., 24 refs.)

  14. A Theoretical Model for Calculating Voltage Sensitivity of Ion Channels and the Application on Kv1.2 Potassium Channel

    Science.gov (United States)

    Yang, Huaiyu; Gao, Zhaobing; Li, Ping; Yu, Kunqian; Yu, Ye; Xu, Tian-Le; Li, Min; Jiang, Hualiang

    2012-01-01

    Voltage sensing confers conversion of a change in membrane potential to signaling activities underlying the physiological processes. For an ion channel, voltage sensitivity is usually experimentally measured by fitting electrophysiological data to Boltzmann distributions. In our study, a two-state model of the ion channel and equilibrium statistical mechanics principle were used to test the hypothesis of empirically calculating the overall voltage sensitivity of an ion channel on the basis of its closed and open conformations, and determine the contribution of individual residues to the voltage sensing. We examined the theoretical paradigm by performing experimental measurements with Kv1.2 channel and a series of mutants. The correlation between the calculated values and the experimental values is at respective level, R2 = 0.73. Our report therefore provides in silico prediction of key conformations and has identified additional residues critical for voltage sensing. PMID:22768937

  15. TRESK potassium channel in human T lymphoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Miguel, Dénison Selene, E-mail: amurusk@hotmail.com [Center for Biomedical Research, University of Colima, Av. 25 de Julio 965, Villa San Sebastian, C.P. 28045 Colima (Mexico); García-Dolores, Fernando, E-mail: garciaddf@yahoo.com [Department of Pathology, Institute of Forensic Sciences, Av. Niños Héroes 130, Col. Doctores, C.P. 06720 Mexico, DF (Mexico); Rosa Flores-Márquez, María, E-mail: mariafo31@yahoo.com.mx [National Medical Center of Occident (CMNO) IMSS, Belisario Dominguez 735, Col. Independencia Oriente, C.P. 44340 Guadalajara, Jalisco (Mexico); Delgado-Enciso, Iván [University of Colima, School of Medicine, Av. Universidad 333, Col. Las Viboras, C.P. 28040 Colima (Mexico); Pottosin, Igor, E-mail: pottosin@ucol.mx [Center for Biomedical Research, University of Colima, Av. 25 de Julio 965, Villa San Sebastian, C.P. 28045 Colima (Mexico); Dobrovinskaya, Oxana, E-mail: oxana@ucol.mx [Center for Biomedical Research, University of Colima, Av. 25 de Julio 965, Villa San Sebastian, C.P. 28045 Colima (Mexico)

    2013-05-03

    Highlights: • TRESK (KCNK18) mRNA is present in different T lymphoblastic cell lines. • KCNK18 mRNA was not found in resting peripheral blood lymphocytes. • Clinical samples of T lymphoblastic leukemias and lymphomas were positive for TRESK. • TRESK in T lymphoblasts has dual localization, in plasma membrane and intracellular. -- Abstract: TRESK (TWIK-related spinal cord K{sup +}) channel, encoded by KCNK18 gene, belongs to the double-pore domain K{sup +} channel family and in normal conditions is expressed predominantly in the central nervous system. In our previous patch-clamp study on Jurkat T lymphoblasts we have characterized highly selective K{sup +} channel with pharmacological profile identical to TRESK. In the present work, the presence of KCNK18 mRNA was confirmed in T lymphoblastic cell lines (Jurkat, JCaM, H9) but not in resting peripheral blood lymphocytes of healthy donors. Positive immunostaining for TRESK was demonstrated in lymphoblastic cell lines, in germinal centers of non-tumoral lymph nodes, and in clinical samples of T acute lymphoblastic leukemias/lymphomas. Besides detection in the plasma membrane, intracellular TRESK localization was also revealed. Possible involvement of TRESK channel in lymphocyte proliferation and tumorigenesis is discussed.

  16. K+ channels and the microglial respiratory burst.

    Science.gov (United States)

    Khanna, R; Roy, L; Zhu, X; Schlichter, L C

    2001-04-01

    Microglial activation following central nervous system damage or disease often culminates in a respiratory burst that is necessary for antimicrobial function, but, paradoxically, can damage bystander cells. We show that several K+ channels are expressed and play a role in the respiratory burst of cultured rat microglia. Three pharmacologically separable K+ currents had properties of Kv1.3 and the Ca2+/calmodulin-gated channels, SK2, SK3, and SK4. mRNA was detected for Kv1.3, Kv1.5, SK2, and/or SK3, and SK4. Protein was detected for Kv1.3, Kv1.5, and SK3 (selective SK2 and SK4 antibodies not available). No Kv1.5-like current was detected, and confocal immunofluorescence showed the protein to be subcellular, in contrast to the robust membrane localization of Kv1.3. To determine whether any of these channels play a role in microglial activation, a respiratory burst was stimulated with phorbol 12-myristate 13-acetate and measured using a single cell, fluorescence-based dihydrorhodamine 123 assay. The respiratory burst was markedly inhibited by blockers of SK2 (apamin) and SK4 channels (clotrimazole and charybdotoxin), and to a lesser extent, by the potent Kv1.3 blocker agitoxin-2. PMID:11245596

  17. KCa2 and KCa3 channels in learning and memory processes, and neurodegeneration

    Directory of Open Access Journals (Sweden)

    Els F. E. Kuiper

    2012-06-01

    Full Text Available Calcium-activated potassium (KCa channels are present throughout the central nervous system as well as many peripheral tissues. Activation of KCa channels is essential for maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of KCa channels were anticipated on the basis of their physiological and pharmacological profiles, and cloning revealed two well defined but phylogenetic distantly related groups of channels. The group subject of this review includes both the small-conductance KCa2 channels (KCa2.1, KCa2.2, and KCa2.3 and the intermediate-conductance (KCa3.1 channel. These channels are activated by submicromolar intracellular Ca2+ concentrations and are voltage independent. Of all KCa channels only the KCa2 channels can be potently but differentially blocked by the bee-venom apamin. In the past few years modulation of KCa channel activation revealed new roles for KCa2 channels in controlling dendritic excitability, synaptic functioning and synaptic plasticity. Furthermore, KCa2 channels appeared to be involved in neurodegeneration, and learning and memory processes. In this review, we focus on the role of KCa2 and KCa3 channels in these latter mechanisms with emphasis on learning and memory, Alzheimer’s disease and on the interplay between neuroinflammation and different neurotransmitters/neuromodulators, their signalling components and KCa channel activation.

  18. Molecular physiology of EAAT anion channels.

    Science.gov (United States)

    Fahlke, Christoph; Kortzak, Daniel; Machtens, Jan-Philipp

    2016-03-01

    Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. After release from presynaptic nerve terminals, glutamate is quickly removed from the synaptic cleft by a family of five glutamate transporters, the so-called excitatory amino acid transporters (EAAT1-5). EAATs are prototypic members of the growing number of dual-function transport proteins: they are not only glutamate transporters, but also anion channels. Whereas the mechanisms underlying secondary active glutamate transport are well understood at the functional and at the structural level, mechanisms and cellular roles of EAAT anion conduction have remained elusive for many years. Recently, molecular dynamics simulations combined with simulation-guided mutagenesis and experimental analysis identified a novel anion-conducting conformation, which accounts for all experimental data on EAAT anion currents reported so far. We here review recent findings on how EAATs accommodate a transporter and a channel in one single protein. PMID:26687113

  19. Implications of Historic River Channel Modifications on Contemporary Restoration Opportunities

    Science.gov (United States)

    Hanrahan, T. P.

    2013-12-01

    Identifying contemporary river management and restoration opportunities relies on understanding how river ecosystems respond to historic forcing from natural events and human impacts. Over the past 70 years, the Big Wood River in central Idaho, USA, has experienced significant engineered channel modifications and realignment, as well as natural changes in channel location and riverbank instability. Understanding the effects of these historic conditions on contemporary river characteristics and processes was needed to inform river management and restoration planning. A geomorphic assessment along 16 km of the Big Wood River was completed in order to understand the physical characteristics and processes upstream, within, and downstream of a 3 km long project reach. This evaluation included analysis of the longitudinal profile, planform pattern, cross-section dimensions, cross-section hydraulics, riverbed and riverbank materials, sediment transport conditions, and large roughness elements such as boulders and large wood material. As a result of residential and highway encroachment along the river corridor, river channel modifications (bank revetments, grade-control drop structures, training channels, sediment traps) have been implemented in attempts to limit the vertical and lateral channel adjustments that would negatively affect infrastructure along the river corridor. These river channel modifications have interrupted the geomorphic processes of the Big Wood River, and have initiated the need for ongoing maintenance of in-channel structures and new efforts at river restoration. Future river ecosystem response along this reach of the Big Wood River will be constrained as a result of river channel and floodplain modifications throughout the valley.

  20. Preventing side-channel effects in continuous-variable quantum key distribution

    Science.gov (United States)

    Derkach, Ivan; Usenko, Vladyslav C.; Filip, Radim

    2016-03-01

    The role of the side channels in the continuous-variable quantum key distribution is studied. It is shown how the information leakage through a side channel from the trusted sender station increases the vulnerability of the protocols to the eavesdropping in the main quantum communication channel. Moreover, the untrusted noise infusion by an eavesdropper on the trusted receiving side breaks the security even for a purely attenuating main quantum channel. As a method to compensate for the effect of the side-channel leakage on the sender side, we suggest several types of manipulations on the side-channel input. It is shown that by applying the modulated coherent light on the input of the side channel that is optimally correlated to the modulation on the main signal and optionally introducing additional squeezing in the case of the squeezed-state protocol, the negative influence of the lossy side channel on the sender side can be completely removed. For the trusted receiving side, the method of optimal monitoring of the residual noise from the side-channel noise infusion is suggested and shown to be able to completely eliminate the presence of the noisy side channel. We therefore prove that the side-channel effects can be completely removed using feasible operations if the trusted parties access the respective parts of the side channels.

  1. All channels open

    NARCIS (Netherlands)

    Frank Huysmans; Jos de Haan

    2010-01-01

    Original title: Alle kanalen staan open. The rapid changes taking place in the media landscape in the Netherlands - characterised by digitisation and convergence of media technologies - raise the question of how the Dutch are dealing with the many new opportunities that have opened up. All channels

  2. Chemistry in Microfluidic Channels

    Science.gov (United States)

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  3. Actinide recovery from pyrochemical residues

    International Nuclear Information System (INIS)

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 62- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO3-4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  4. Binding site residues control inhibitor selectivity in the human norepinephrine transporter but not in the human dopamine transporter

    DEFF Research Database (Denmark)

    Andersen, Jacob; Ringsted, Kristoffer B; Bang-Andersen, Benny; Strømgaard, Kristian; Kristensen, Anders S

    2015-01-01

    in the central site of DAT to the corresponding residues in NET had modest effects on the same inhibitors, suggesting that non-conserved binding site residues in DAT play a minor role for selective inhibitor recognition. Our data points towards distinct structural determinants governing inhibitor...

  5. Glutamate transporters combine transporter- and channel-like features

    NARCIS (Netherlands)

    Slotboom, DJ; Konings, WN; Lolkema, JS

    2001-01-01

    Glutamate transporters in the mammalian central nervous system have a unique position among secondary transport proteins as they exhibit glutamate-gated chloride-channel activity in addition to glutamate-transport activity. In this article, the available data on the structure of the glutamate transp

  6. Leaching From Biomass Gasification Residues

    DEFF Research Database (Denmark)

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.;

    2011-01-01

    composition, and DOC complexation and sorption mechanisms were found to have a great influence on their release. Like wood combustion residues, the analysed ashes could be relevant for recycling in agriculture or forestry because of the potential as liming agent and source of macroelements. However, the high...... geochemical modelling were carried out both on fresh and aged samples. The results showed that the material is comparable to residues from wood combustion and the leaching behaviour was dominated by Ca-containing minerals and solid solutions. Heavy metals were detected in very low concentrations in the bulk...

  7. Peptide iodination on phenylalanine residues

    International Nuclear Information System (INIS)

    Peptide labelling with radioactive isotopes is always a compromise between peptide chemistry, labelling chemistry, and biological receptor tolerance. Therefore new ways for isotope introduction are always useful. The present contribution describes the introduction of iodine isotopes onto synthetic polypeptides by means of the Gattermann/ Sandmeyer reactions. Peptides containing the nitrophenylalanyl residue are reduced to the corresponding aminophenylalanyl, diazolized to the diazonium phenylalanyl peptide and converted to the iodophenylalanyl peptide in the presence of copper. Two examples are presented: angiotensin II and enkephalin. In both cases, the iodophenylalanyl residue is well accepted by the biological target. (author). 13 refs.; 4 figs

  8. Residual Structures in Latent Growth Curve Modeling

    Science.gov (United States)

    Grimm, Kevin J.; Widaman, Keith F.

    2010-01-01

    Several alternatives are available for specifying the residual structure in latent growth curve modeling. Two specifications involve uncorrelated residuals and represent the most commonly used residual structures. The first, building on repeated measures analysis of variance and common specifications in multilevel models, forces residual variances…

  9. Residues for flags of holomorphic foliations

    OpenAIRE

    Brasselet, Jean-Paul; Corrêa, Maurício; Lourenço, Fernando

    2016-01-01

    In this work we prove a Baum-Bott type residues theorem for flags of holomorphic foliations. We prove some relations between the residues of the flag and the residues of their correspondent foliations. We define the Nash residue for flags and we prove that the Bott rationality conjecture holds in this context.

  10. Alternatives to crop residues for soil amendment

    OpenAIRE

    Powell, J.M.; Unger, P.W.

    1997-01-01

    Metadata only record In semiarid agroecosystems, crop residues can provide important benefits of soil and water conservation, nutrient cycling, and improved subsequent crop yields. However, there are frequently multiple competing uses for residues, including animal forage, fuel, and construction material. This chapter discusses the various uses of crop residues and examines alternative soil amendments when crop residues cannot be left on the soil.

  11. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle;

    2006-01-01

    pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  12. KCNQ Modulators Reveal a Key Role for KCNQ Potassium Channels in Regulating the Tone of Rat Pulmonary Artery Smooth Muscle

    OpenAIRE

    Joshi, Shreena; Sedivy, Vojtech; Hodyc, Daniel; Herget, Jan; Gurney, Alison M

    2009-01-01

    Potassium channels are central to the regulation of pulmonary vascular tone. The smooth muscle cells of pulmonary artery display a background K+ conductance with biophysical properties resembling those of KCNQ (KV7) potassium channels. Therefore, we investigated the expression and functional role of KCNQ channels in pulmonary artery. The effects of selective KCNQ channel modulators were investigated on K+ current and membrane potential in isolated pulmonary artery smoo...

  13. Spatial patterns in suprabenthic communities in the English Channel

    Science.gov (United States)

    Dauvin, Jean-Claude; Rolet, Céline; Alizier, Sandrine; Ruellet, Thierry

    2011-01-01

    The purpose of this paper was to establish the main characteristics of the suprabenthic communities of the English Channel including those found in a potential aggregate extraction zone located in the central part. Sampling was carried out with a Macer-GIROQ sledge during four periods in 2007. In this offshore site, the suprabenthic faunal composition and abundance were close to those observed in other similar sites in coarse sand to pebbles in the western and eastern parts of the English Channel. But, the species richness was low (65 species). Amphipods were the dominant group in terms of diversity and abundance. Only a few species, mostly amphipods and decapods, showed significant daily migration. Seasonal variations were moderate. Due to the similar suprabenthic fauna having good swimming ability, the aggregate extraction zone in the central part of the Channel could be rapidly colonized after exploitation and thus could rapidly insure a feeding resource for fish, which are attracted by abundant prey.

  14. Threonine in the selectivity filter of the acetylcholine receptor channel.

    OpenAIRE

    Villarroel, A.; Sakmann, B

    1992-01-01

    The acetylcholine receptor (AChR) is a cation selective channel whose biophysical properties as well as its molecular composition are fairly well characterized. Previous studies on the rat muscle alpha-subunit indicate that a threonine residue located near the cytoplasmic side of the M2 segment is a determinant of ion flow. We have studied the role of this threonine in ionic selectivity by measuring conductance sequences for monovalent alkali cations and bionic reversal potentials of the wild...

  15. Seismic stratigraphy and clay mineral distribution in shallow-marine siliciclastic deposits, central Mississippi sound, North-central Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Harper, G.G.; Manley, F.H.; Staheli, A.C.

    1983-03-01

    Three north-south high-resolution (7 kHz) seismic profiles and 16 20-foot cores taken at shot-point locations in central Mississippi Sound were utilized to determine: (1) any meaningful seismic reflector configurations in the subsurface; (2) the clay species dispersal pattern and its relation to transport systems that move sediment into the depositional basin; (3) any change in clay mineral species that has occurred through time with respect to deposition of 5 to 6 m (16 to 20 ft) of sediment. Interpretation of shallow seismic events (20 m (66 ft)) and clay mineral analysis indicates that extrinsic factors largely determined the clay mineral species and geologic history of Pleistocene and Holocene sedimentation in central Mississippi Sound. Trend surface maps, residual maps, profiles of the smectite (montmorillonite) to kaolinite ratios, and seismic profiles illustrate that: (1) Mississippi Sound has been influenced by transgressions and regressions associated with proglacial and interglacial stages; (2) a toplap seismic reflection configuration forms the probable Pleistocene-Holocene boundary; (3) at least one ancient barrier island is located inside the Holocene barrier system; (4) there is a late date for sea level reaching its present location (2500 years B.P.); (5) the influence of the Mississippi River system on sedimentation is soon after inundation of Mississippi Sound; (6) the longshore currents and flood tides supplied sediment rich in kaolinite to the study area; (7) the drainage systems emptying into the study area have local influence on clay mineral distribution; and (8) the dredging of ship channels affects the clay-mineral distribution within the sediments immediately below the sediment-water interface in central Mississippi Sound.

  16. A New Covert Channel over Cellular Voice Channel in Smartphones

    OpenAIRE

    Aloraini, Bushra; Johnson, Daryl; Stackpole, Bill; Mishra, Sumita

    2015-01-01

    Investigating network covert channels in smartphones has become increasingly important as smartphones have recently replaced the role of traditional computers. Smartphones are subject to traditional computer network covert channel techniques. Smartphones also introduce new sets of covert channel techniques as they add more capabilities and multiple network connections. This work presents a new network covert channel in smartphones. The research studies the ability to leak information from the...

  17. Improving Virtual Channel Discrimination in a Multi-Channel Context

    OpenAIRE

    Srinivasan, Arthi G.; Shannon, Robert V.; Landsberger, David M.

    2012-01-01

    Improving spectral resolution in cochlear implants is key to improving performance in difficult listening conditions (e.g. speech in noise, music, etc.). Current focusing might reduce channel interaction, thereby increasing spectral resolution. Previous studies have shown that combining current steering and current focusing reduces spread of excitation and improves virtual channel discrimination in a single-channel context. It is unclear whether the single-channel benefits from current focusi...

  18. Consumer channel choice: integrating electronic and conventional service channels

    OpenAIRE

    van Dijk, Geke; Laing, Angus; Minocha, Shailey

    2006-01-01

    When investigating the consumer experience in multi-channel retail service environments, one of the more themes is the decision-making process on channel choice. Most of the literature on channel choice addresses it as a single decision during the consumption process. The study reported in this paper describes how consumers often make several channel choices throughout the consumption process. The described study is an ethnographically inspired, in-depth case study that examined online and of...

  19. Oxidation of a potassium channel causes progressive sensory function loss during ageing

    OpenAIRE

    Cai, Shi-Qing; Sesti, Federico

    2009-01-01

    A central question is whether potassium (K+) channels, which are key regulators of neuronal excitability, are targets of reactive oxygen species (ROS) and whether these interactions have a role in the mechanisms underlying neurodegeneration. Here, we show that oxidation of K+ channel KVS-1 during ageing causes sensory function loss in Caenorhabditis elegans, and that protection of this channel from oxidation preserves neuronal function. Chemotaxis, a function controlled by KVS-1, was signific...

  20. KCa2 and KCa3 Channels in Learning and Memory Processes, and Neurodegeneration

    OpenAIRE

    Kuiper, Els F. E.; Nelemans, Ad; Luiten, Paul; Nijholt, Ingrid; Dolga, Amalia; Eisel, Uli

    2012-01-01

    Calcium-activated potassium (KCa) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of KCa channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of KCa channels were anticipated on the basis of their physiological and pharmacological profiles,...

  1. KCa2 and KCa3 channels in learning and memory processes, and neurodegeneration

    OpenAIRE

    AdNelemans; AmaliaMDolga

    2012-01-01

    Calcium-activated potassium (KCa) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of KCa channels is essential for maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of KCa channels were anticipated on the basis of their physiological and pharmacological profil...

  2. A homology model of the pore domain of a voltage-gated calcium channel is consistent with available SCAM data

    OpenAIRE

    Bruhova, Iva; Zhorov, Boris S.

    2010-01-01

    In the absence of x-ray structures of calcium channels, their homology models are used to rationalize experimental data and design new experiments. The modeling relies on sequence alignments between calcium and potassium channels. Zhen et al. (2005. J. Gen. Physiol. doi:10.1085/jgp.200509292) used the substituted cysteine accessibility method (SCAM) to identify pore-lining residues in the Cav2.1 channel and concluded that their data are inconsistent with the symmetric architecture of the pore...

  3. On the structural basis for ionic selectivity among Na+, K+, and Ca2+ in the voltage-gated sodium channel.

    OpenAIRE

    Favre, I; Moczydlowski, E; Schild, L

    1996-01-01

    Voltage-sensitive sodium channels and calcium channels are homologous proteins with distinctly different selectivity for permeation of inorganic cations. This difference in function is specified by amino acid residues located within P-region segments that link presumed transmembrane elements S5 and S6 in each of four repetitive Domains I, II, III, and IV. By analyzing the selective permeability of Na+, K+, and Ca2+ in various mutants of the mu 1 rat muscle sodium channel, the results in this ...

  4. Ion channels modulating mouse dendritic cell functions.

    Science.gov (United States)

    Matzner, Nicole; Zemtsova, Irina M; Nguyen, Thi Xuan; Duszenko, Michael; Shumilina, Ekaterina; Lang, Florian

    2008-11-15

    Ca(2+)-mediated signal transduction pathways play a central regulatory role in dendritic cell (DC) responses to diverse Ags. However, the mechanisms leading to increased [Ca(2+)](i) upon DC activation remained ill-defined. In the present study, LPS treatment (100 ng/ml) of mouse DCs resulted in a rapid increase in [Ca(2+)](i), which was due to Ca(2+) release from intracellular stores and influx of extracellular Ca(2+) across the cell membrane. In whole-cell voltage-clamp experiments, LPS-induced currents exhibited properties similar to the currents through the Ca(2+) release-activated Ca(2+) channels (CRAC). These currents were highly selective for Ca(2+), exhibited a prominent inward rectification of the current-voltage relationship, and showed an anomalous mole fraction and a fast Ca(2+)-dependent inactivation. In addition, the LPS-induced increase of [Ca(2+)](i) was sensitive to margatoxin and ICAGEN-4, both inhibitors of voltage-gated K(+) (Kv) channels Kv1.3 and Kv1.5, respectively. MHC class II expression, CCL21-dependent migration, and TNF-alpha and IL-6 production decreased, whereas phagocytic capacity increased in LPS-stimulated DCs in the presence of both Kv channel inhibitors as well as the I(CRAC) inhibitor SKF-96365. Taken together, our results demonstrate that Ca(2+) influx in LPS-stimulated DCs occurs via Ca(2+) release-activated Ca(2+) channels, is sensitive to Kv channel activity, and is in turn critically important for DC maturation and functions. PMID:18981098

  5. Eddies in the southern Mozambique Channel

    Science.gov (United States)

    Quartly, G. D.; Srokosz, M. A.

    2004-01-01

    The Agulhas Current system contains one of the world's strongest western boundary currents, and plays an important part in the warm water path of the global thermohaline circulation. However, there have been few surveys of the source regions of the Agulhas Current, and thus little in situ measurement of their variability. Utilizing the more than 5-year record of SeaWiFS data, we examine the eddy activity present in the southern portion of the Mozambique Channel. The two sources of Agulhas input from the central Indian Ocean (southward flow through the Mozambique Channel and westward flow around the southern limit of Madagascar) both show great temporal variability, with no clear seasonal signal. A number of large (˜200 km diameter) anticyclonic rings intermittently propagate poleward along the western edge of the channel, sweeping coastal waters into mid-channel. Their passage past Maputo appears to affect the circulation of the lee eddy in the Delagoa Bight. The eastern side of the channel is mainly characterized by cyclonic eddies. These are made manifest in the lee of the southern tip of Madagascar, although it is not clear whether many form there or just develop a visible presence due to entrainment of high-chlorophyll coastal waters. Several of these cyclonic eddies then appear to move in west-southwesterly direction. The chlorophyll data do reveal the apparent East Madagascar Retroflection on occasions, but do not show clear examples of the pinching off of anticyclonic eddies. However, surface waters from the East Madagascar Current may reach the African mainland on occasions when no retroflection is present.

  6. Solidification process for sludge residue

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, K.L.

    1998-09-10

    This report investigates the solidification process used at 100-N Basin to solidify the N Basin sediment and assesses the N Basin process for application to the K Basin sludge residue material. This report also includes a discussion of a solidification process for stabilizing filters. The solidified matrix must be compatible with the Environmental Remediation Disposal Facility acceptance criteria.

  7. Solidification process for sludge residue

    International Nuclear Information System (INIS)

    This report investigates the solidification process used at 100-N Basin to solidify the N Basin sediment and assesses the N Basin process for application to the K Basin sludge residue material. This report also includes a discussion of a solidification process for stabilizing filters. The solidified matrix must be compatible with the Environmental Remediation Disposal Facility acceptance criteria

  8. IMPROVED TECHNIQUES FOR RESIDUAL OZONE

    Science.gov (United States)

    Eight analytical methods for the determination of residual ozone in water are evaluated. Four are iodometric methods based on the reduction of ozone by iodide ion: the iodometric method, the amperometric method, the arsenic (III) back titration method, and the N, N-diethyl-p-phen...

  9. Pyrotechnic reaction residue particle analysis.

    Science.gov (United States)

    Kosanke, Kenneth L; Dujay, Richard C; Kosanke, Bonnie J

    2006-03-01

    Pyrotechnic reaction residue particle (PRRP) production, sampling and analysis are all very similar to that for primer gunshot residue. In both cases, the preferred method of analysis uses scanning electron microscopy to locate suspect particles and then uses energy dispersive x-ray spectroscopy to characterize the particle's constituent chemical elements. There are relatively few times when standard micro-analytical chemistry performed on pyrotechnic residues may not provide sufficient information for forensic investigators. However, on those occasions, PRRP analysis provides a greatly improved ability to discriminate between materials of pyrotechnic origin and other unrelated substances also present. The greater specificity of PRRP analysis is the result of its analyzing a large number of individual micron-sized particles, rather than producing only a single integrated result such as produced using standard micro-analytical chemistry. For example, PRRP analyses are used to demonstrate its ability to successfully (1) discriminate between pyrotechnic residues and unrelated background contamination, (2) identify that two different pyrotechnic compositions had previously been exploded within the same device, and (3) establish the chronology of an incident involving two separate and closely occurring explosions. PMID:16566762

  10. Landfill Mining of Shredder Residues

    DEFF Research Database (Denmark)

    Hansen, Jette Bjerre; Hyks, Jiri; Shabeer Ahmed, Nassera;

    In Denmark, shredder residues (SR) are classified as hazardous waste and until January 2012 the all SR were landfilled. It is estimated that more than 1.8 million tons of SR have been landfilled in mono cells. This paper describes investigations conducted at two Danish landfills. SR were excavated...

  11. Central Neuropathic Pain Syndromes.

    Science.gov (United States)

    Watson, James C; Sandroni, Paola

    2016-03-01

    Chronic pain is common in patients with neurologic complications of a central nervous system insult such as stroke. The pain is most commonly musculoskeletal or related to obligatory overuse of neurologically unaffected limbs. However, neuropathic pain can result directly from the central nervous system injury. Impaired sensory discrimination can make it challenging to differentiate central neuropathic pain from other pain types or spasticity. Central neuropathic pain may also begin months to years after the injury, further obscuring recognition of its association with a past neurologic injury. This review focuses on unique clinical features that help distinguish central neuropathic pain. The most common clinical central pain syndromes-central poststroke pain, multiple sclerosis-related pain, and spinal cord injury-related pain-are reviewed in detail. Recent progress in understanding of the pathogenesis of central neuropathic pain is reviewed, and pharmacological, surgical, and neuromodulatory treatments of this notoriously difficult to treat pain syndrome are discussed. PMID:26944242

  12. NIDDK Central Repository

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIDDK Central Repository stores biosamples, genetic and other data collected in designated NIDDK-funded clinical studies. The purpose of the NIDDK Central...

  13. Quantum communication under channel uncertainty

    International Nuclear Information System (INIS)

    This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

  14. Central and peripheral demyelination

    OpenAIRE

    Man Mohan Mehndiratta; Natasha Singh Gulati

    2014-01-01

    Several conditions cause damage to the inherently normal myelin of central nervous system, perepheral nervous system or both central and perepheral nervous system and hence termed as central demyelinating diseases, perepheral demyelinating diseases and combined central and perepheral demyelinating diseases respectively. Here we analysed and foccused on the etiology, prevalance, incidence and age of these demyelinating disorders. Clinical attention and various diagnostic tests are needed to ad...

  15. Muon cooling channels

    International Nuclear Information System (INIS)

    Parameters of muon cooling channels are discussed that achieve cooling of a muon beam from initial to final emittances in all three degrees of freedom in a given length. Published theories of ionisation cooling yield equilibrium emittances from multiple scattering and energy straggling, and partition numbers. Limits are obtained on the amplitude functions in all three degrees of freedom. Parameters of wedge-shaped absorbers and partition numbers are derived for simultaneous longitudinal and transverse cooling. Limits on length and material of absorbers, and dispersion at the wedge-shaped absorbers are obtained. Parameters are presented for the RF system, e.g. peak voltage, frequency, and stable phase angle. The properties of the magnetic lattice which satisfies the conditions imposed by the longitudinal dynamics are studied. The consequences of changes in the assumed performance of the cooling channel on its parameters are discussed

  16. Boosted Higgs channels

    International Nuclear Information System (INIS)

    In gluon fusion both a modified top Yukawa and new colored particles can alter the cross section. However in a large set of composite Higgs models and in realistic areas of the MSSM parameter space, these two effects can conspire and hide new physics in a Standard Model-like inclusive cross section. We first show that it is possible to break this degeneracy in the couplings by demanding a boosted Higgs recoiling against a high-pT jet. Subsequently we propose an analysis based on this idea in the H→2l+ET channels. This measurement allows an alternative determination of the important top Yukawa besides the t anti tH channel.

  17. Lipid Ion Channels

    CERN Document Server

    Heimburg, Thomas

    2010-01-01

    The interpretation electrical phenomena in biomembranes is usually based on the assumption that the experimentally found discrete ion conduction events are due to a particular class of proteins called ion channels while the lipid membrane is considered being an inert electrical insulator. The particular protein structure is thought to be related to ion specificity, specific recognition of drugs by receptors and to macroscopic phenomena as nerve pulse propagation. However, lipid membranes in their chain melting regime are known to be highly permeable to ions, water and small molecules, and are therefore not always inert. In voltage-clamp experiments one finds quantized conduction events through protein-free membranes in their melting regime similar to or even undistinguishable from those attributed to proteins. This constitutes a conceptual problem for the interpretation of electrophysiological data obtained from biological membrane preparations. Here, we review the experimental evidence for lipid ion channels...

  18. Geysering in boiling channels

    Energy Technology Data Exchange (ETDEWEB)

    Aritomi, Masanori; Takemoto, Takatoshi [Tokyo Institute of Technology, Tokyo (Japan); Chiang, Jing-Hsien [Japan NUS Corp. Ltd., Toyko (Japan)] [and others

    1995-09-01

    A concept of natural circulation BWRs such as the SBWR has been proposed and seems to be promising in that the primary cooling system can be simplified. The authors have been investigating thermo-hydraulic instabilities which may appear during the start-up in natural circulation BWRs. In our previous works, geysering was investigated in parallel boiling channels for both natural and forced circulations, and its driving mechanism and the effect of system pressure on geysering occurrence were made clear. In this paper, geysering is investigated in a vertical column and a U-shaped vertical column heated in the lower parts. It is clarified from the results that the occurrence mechanism of geysering and the dependence of system pressure on geysering occurrence coincide between parallel boiling channels in circulation systems and vertical columns in non-circulation systems.

  19. Sensing Task Allocation for Heterogeneous Channels in Cooperative Spectrum Sensing

    Directory of Open Access Journals (Sweden)

    Qihui Wu

    2010-12-01

    Full Text Available In the traditional centralized cooperative spectrum sensing, all secondary users sense the same channel. But, for a given channel, there exists detection performance diversity among all the users, due to the different signal-fading process. Involving the user with poor performance in cooperative sensing will not only deteriorate the detection correctness but also waste the sensing time. In the heterogeneous channels, the problem is even severe. A novel idea is to allocate the secondary users to sense different channels. We analyze the allocation problem before formulate it to be an optimization problem, which is a NP-hard problem. Then we propose the declined complexity algorithm in equal secondary user case and the two-hierarchy approach algorithm in unequal case. With the simulation, we verify the near optimality of the proposed algorithms and the advantage of the task allocation.

  20. Proton channel models

    OpenAIRE

    Pupo, Amaury; Baez-Nieto, David; Martínez, Agustín; Latorre, Ramón; González, Carlos

    2014-01-01

    Voltage-gated proton channels are integral membrane proteins with the capacity to permeate elementary particles in a voltage and pH dependent manner. These proteins have been found in several species and are involved in various physiological processes. Although their primary topology is known, lack of details regarding their structures in the open conformation has limited analyses toward a deeper understanding of the molecular determinants of their function and regulation. Consequently, the f...

  1. Convolutional Channel Features

    OpenAIRE

    Yang, Bin; Yan, Junjie; Lei, Zhen; Li, Stan Z.

    2015-01-01

    Deep learning methods are powerful tools but often suffer from expensive computation and limited flexibility. An alternative is to combine light-weight models with deep representations. As successful cases exist in several visual problems, a unified framework is absent. In this paper, we revisit two widely used approaches in computer vision, namely filtered channel features and Convolutional Neural Networks (CNN), and absorb merits from both by proposing an integrated method called Convolutio...

  2. Radar channel balancing with commutation

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.

  3. The alpha channeling effect

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N. J.

    2015-12-10

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  4. DMT of weighted Parallel Channels: Application to Broadcast Channel

    CERN Document Server

    Mroueh, Lina; Othman, Ghaya Rekaya-Ben; Belfiore, Jean-Claude

    2008-01-01

    In a broadcast channel with random packet arrival and transmission queues, the stability of the system is achieved by maximizing a weighted sum rate capacity with suitable weights that depend on the queue size. The weighted sum rate capacity using Dirty Paper Coding (DPC) and Zero Forcing (ZF) is asymptotically equivalent to the weighted sum capacity over parallel single-channels. In this paper, we study the Diversity Multiplexing Tradeoff (DMT) of the fading broadcast channel under a fixed weighted sum rate capacity constraint. The DMT of both identical and different parallel weighted MISO channels is first derived. Finally, we deduce the DMT of a broadcast channel using DPC and ZF precoders.

  5. Population, Biomass and the Environment in Central Sudan

    OpenAIRE

    H.M. Yousif

    1994-01-01

    This paper deals specifically with population-biomass-environment interactions in the semi-arid central region of Sudan. Most of the links and dynamics operate at the local-scale household level. Living arrangements within the household, household size, size of consuming units, location and mode of living (urban-rural-nomadic) are some of the most important link variables. Biomass fuels use (fuelwood, charcoal, crop residues and animal dung) in the central region varies considerably by locati...

  6. Crystal structure of the drug-resistant S31N influenza M2 proton channel.

    Science.gov (United States)

    Thomaston, Jessica L; DeGrado, William F

    2016-08-01

    The M2 protein is a small proton channel found in the influenza A virus that is necessary for viral replication. The M2 channel is the target of a class of drugs called the adamantanes, which block the channel pore and prevent the virus from replicating. In recent decades mutations have arisen in M2 that prevent the adamantanes from binding to the channel pore, with the most prevalent of these mutations being S31N. Here we report the first crystal structure of the S31N mutant crystallized using lipidic cubic phase crystallization techniques and solved to 1.59 Å resolution. The Asn31 residues point directly into the center of the channel pore and form a hydrogen-bonded network that disrupts the drug-binding site. Ordered waters in the channel pore form a continuous hydrogen bonding network from Gly34 to His37. PMID:27082171

  7. Nomenclature for Ion channel Subunits

    OpenAIRE

    Bradley, Jonathan; Frings, Stephan; Yau, King-Wai; Reed, Randall

    2001-01-01

    Presents the nomenclature for ion channel subunits. Role of ion channels in the mediation of visual and olfactory signal transduction; Expression of ion channels in cell types and tissues; Assessment on the nucleotide sensitivity, ion conductance and calcium modulation in heteromers.

  8. On partially entanglement breaking channels

    OpenAIRE

    Chruściński, Dariusz; Kossakowski, Andrzej

    2005-01-01

    Using well known duality between quantum maps and states of composite systems we introduce the notion of Schmidt number of a quantum channel. It enables one to define classes of quantum channels which partially break quantum entanglement. These classes generalize the well known class of entanglement breaking channels.

  9. Micro-channel plate detector

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  10. Radioactive material in residues of health services residues

    International Nuclear Information System (INIS)

    The work presents the operational actions developed by the one organ responsible regulator for the control of the material use radioactive in Brazil. Starting from the appearance of coming radioactive material of hospitals and clinical with services of nuclear medicine, material that that is picked up and transported in specific trucks for the gathering of residuals of hospital origin, and guided one it manufactures of treatment of residuals of services of health, where they suffer radiological monitoring before to guide them for final deposition in sanitary embankment, in the city of Sao Paulo, Brazil. The appearance of this radioactive material exposes a possible one violation of the norms that govern the procedures and practices in that sector in the country. (Author)

  11. Identification of key residues involved in Si transport by the aquaglyceroporins.

    Science.gov (United States)

    Carpentier, Gabriel A; Garneau, Alexandre P; Marcoux, Andrée-Anne; Noël, Micheline; Frenette-Cotton, Rachelle; Isenring, Paul

    2016-09-01

    We recently demonstrated that the aquaglyceroporins (AQGPs) could act as potent transporters for orthosilicic acid (H4SiO4). Although interesting, this finding raised the question of whether water and H4SiO4, the transportable form of Si, permeate AQGPs by interacting with the same region of the pore, especially in view of the difference in molecular radius between the two substrates. Here, our goal was to identify residues that endow the AQGPs with the ability to facilitate Si diffusion by examining the transport characteristics of mutants in which residues were interchanged between a water-permeable but Si-impermeable channel (aquaporin 1 [AQP1]) and a Si-permeable but water-impermeable channel (AQP10). Our results indicate that the composition of the arginine filter (XX/R), known to include three residues that play an important role in water transport, may also be involved in Si selectivity. Interchanging the identities of the nonarginine residues within this filter causes Si transport to increase by approximately sevenfold in AQP1 and to decrease by approximately threefold in AQP10, whereas water transport and channel expression remain unaffected. Our results further indicate that two additional residues in the AQP arginine filter may be involved in substrate selectivity: replacing one of the residues has a profound effect on water permeability, and replacing the other has a profound effect on Si permeability. This study has thus led to the identification of residues that could play a key role in Si transport by the AQGPs and shown that substrate selectivity is likely ensured by more than one checkpoint within or near the pore. PMID:27527099

  12. A molecular determinant of phosphoinositide affinity in mammalian TRPV channels.

    Science.gov (United States)

    Velisetty, Phanindra; Borbiro, Istvan; Kasimova, Marina A; Liu, Luyu; Badheka, Doreen; Carnevale, Vincenzo; Rohacs, Tibor

    2016-01-01

    Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is an important cofactor for ion channels. Affinity for this lipid is a major determinant of channel inhibition by depletion of PI(4,5)P2 upon phospholipase C (PLC) activation. Little is known about what determines PI(4,5)P2 affinity in mammalian ion channels. Here we report that two members of the Transient Receptor Potential Vanilloid (TRPV) ion channel family, TRPV5 and TRPV6 lack a positively charged residue in the TM4-TM5 loop that was shown to interact with PI(4,5)P2 in TRPV1, which shows high affinity for this lipid. When this positively charged residue was introduced to either TRPV6 or TRPV5, they displayed markedly higher affinities for PI(4,5)P2, and were largely resistant to inhibition by PI(4,5)P2 depletion. Furthermore, Ca(2+)-induced inactivation of TRPV6 was essentially eliminated in the G488R mutant, showing the importance of PLC-mediated PI(4,5)P2 depletion in this process. Computational modeling shows that the introduced positive charge interacts with PI(4,5)P2 in TRPV6. PMID:27291418

  13. Zinc as Allosteric Ion Channel Modulator: Ionotropic Receptors as Metalloproteins

    Science.gov (United States)

    Peralta, Francisco Andrés; Huidobro-Toro, Juan Pablo

    2016-01-01

    Zinc is an essential metal to life. This transition metal is a structural component of many proteins and is actively involved in the catalytic activity of cell enzymes. In either case, these zinc-containing proteins are metalloproteins. However, the amino acid residues that serve as ligands for metal coordination are not necessarily the same in structural proteins compared to enzymes. While crystals of structural proteins that bind zinc reveal a higher preference for cysteine sulfhydryls rather than histidine imidazole rings, catalytic enzymes reveal the opposite, i.e., a greater preference for the histidines over cysteines for catalysis, plus the influence of carboxylic acids. Based on this paradigm, we reviewed the putative ligands of zinc in ionotropic receptors, where zinc has been described as an allosteric modulator of channel receptors. Although these receptors do not strictly qualify as metalloproteins since they do not normally bind zinc in structural domains, they do transitorily bind zinc at allosteric sites, modifying transiently the receptor channel’s ion permeability. The present contribution summarizes current information showing that zinc allosteric modulation of receptor channels occurs by the preferential metal coordination to imidazole rings as well as to the sulfhydryl groups of cysteine in addition to the carboxyl group of acid residues, as with enzymes and catalysis. It is remarkable that most channels, either voltage-sensitive or transmitter-gated receptor channels, are susceptible to zinc modulation either as positive or negative regulators. PMID:27384555

  14. Atomic basis for therapeutic activation of neuronal potassium channels

    DEFF Research Database (Denmark)

    Kim, Robin Y; Yau, Michael C; Galpin, Jason D;

    2015-01-01

    Retigabine is a recently approved anticonvulsant that acts by potentiating neuronal M-current generated by KCNQ2-5 channels, interacting with a conserved Trp residue in the channel pore domain. Using unnatural amino-acid mutagenesis, we subtly altered the properties of this Trp to reveal specific...... fluorinated Trp analogues, with increased H-bonding propensity, strengthens retigabine potency. In addition, potency of numerous retigabine analogues correlates with the negative electrostatic surface potential of a carbonyl/carbamate oxygen atom present in most KCNQ activators. These findings functionally...... pinpoint an atomic-scale interaction essential for effects of retigabine and provide stringent constraints that may guide rational improvement of the emerging drug class of KCNQ channel activators....

  15. Wavelength-selective fluorescence in ion channels formed by gramicidin A in membranes

    Indian Academy of Sciences (India)

    Amitabha Chattopadhyay; Satinder S Rawat

    2007-03-01

    Gramicidins are linear peptides that form ion channels that are specific for monovalent cations in membranes. The tryptophan residues in the gramicidin channel play a crucial role in the organization and function of the channel. The natural mixture of gramicidins, denoted as gramicidin A', consists of mostly gramicidin A, but also contains gramicidins B, C and D as minor components. We have previously shown that the tryptophan residues in ion channels formed by the naturally occurring peptide, gramicidin A', display wavelength-dependent fluorescence characteristics due to the motionally restricted environment in which they are localized. In order to check the influence of ground-state heterogeneity in the observed wavelength-selective fluorescence of gramicidin A' in membranes, we performed similar experiments with pure gramicidin A in model membranes. Our results show that the observed wavelength-selective fluorescence characteristics of naturally occurring gramicidin A' are not due to groundstate heterogeneity.

  16. MIMO Wiretap Channels with Arbitrarily Varying Eavesdropper Channel States

    CERN Document Server

    He, Xiang

    2010-01-01

    In this work, a class of information theoretic secrecy problems is addressed where the eavesdropper channel states are completely unknown to the legitimate parties. In particular, MIMO wiretap channel models are considered where the channel of the eavesdropper is arbitrarily varying over time. Assuming that the number of antennas of the eavesdropper is limited, the secrecy rate of the MIMO wiretap channel in the sense of strong secrecy is derived, and shown to match with the converse in secure degrees of freedom. It is proved that there exists a universal coding scheme that secures the confidential message against any sequence of channel states experienced by the eavesdropper. This yields the conclusion that secure communication is possible regardless of the location or channel states of (potentially infinite number of) eavesdroppers. Additionally, it is observed that, the present setting renders the secrecy capacity problems for multi-terminal wiretap-type channels more tractable as compared the case with fu...

  17. Targeting the Small- and Intermediate-Conductance Ca2+-Activated Potassium Channels: The Drug-Binding Pocket at the Channel/Calmodulin Interface

    Directory of Open Access Journals (Sweden)

    Meng Cui

    2014-10-01

    Full Text Available The small- and intermediate-conductance Ca2+-activated potassium (SK/IK channels play important roles in the regulation of excitable cells in both the central nervous and cardiovascular systems. Evidence from animal models has implicated SK/IK channels in neurological conditions such as ataxia and alcohol use disorders. Further, genome-wide association studies have suggested that cardiovascular abnormalities such as arrhythmias and hypertension are associated with single nucleotide polymorphisms that occur within the genes encoding the SK/IK channels. The Ca2+ sensitivity of the SK/IK channels stems from a constitutively bound Ca2+-binding protein: calmodulin. Small-molecule positive modulators of SK/IK channels have been developed over the past decade, and recent structural studies have revealed that the binding pocket of these positive modulators is located at the interface between the channel and calmodulin. SK/IK channel positive modulators can potentiate channel activity by enhancing the coupling between Ca2+ sensing via calmodulin and mechanical opening of the channel. Here, we review binding pocket studies that have provided structural insight into the mechanism of action for SK/IK channel positive modulators. These studies lay the foundation for structure-based drug discovery efforts that can identify novel SK/IK channel positive modulators. © 2014 S. Karger AG, Basel

  18. 2D IR spectroscopy reveals the role of water in the binding of channel-blocking drugs to the influenza M2 channel

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Ayanjeet, E-mail: ayanjeet@sas.upenn.edu, E-mail: gai@sas.upenn.edu; Gai, Feng, E-mail: ayanjeet@sas.upenn.edu, E-mail: gai@sas.upenn.edu; Hochstrasser, Robin M. [Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Wang, Jun; DeGrado, William F. [Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94143 (United States); Moroz, Yurii S.; Korendovych, Ivan V. [Department of Chemistry, Syracuse University, Syracuse, New York 13244 (United States); Zanni, Martin [Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2014-06-21

    Water is an integral part of the homotetrameric M2 proton channel of the influenza A virus, which not only assists proton conduction but could also play an important role in stabilizing channel-blocking drugs. Herein, we employ two dimensional infrared (2D IR) spectroscopy and site-specific IR probes, i.e., the amide I bands arising from isotopically labeled Ala30 and Gly34 residues, to probe how binding of either rimantadine or 7,7-spiran amine affects the water dynamics inside the M2 channel. Our results show, at neutral pH where the channel is non-conducting, that drug binding leads to a significant increase in the mobility of the channel water. A similar trend is also observed at pH 5.0 although the difference becomes smaller. Taken together, these results indicate that the channel water facilitates drug binding by increasing its entropy. Furthermore, the 2D IR spectral signatures obtained for both probes under different conditions collectively support a binding mechanism whereby amantadine-like drugs dock in the channel with their ammonium moiety pointing toward the histidine residues and interacting with a nearby water cluster, as predicted by molecular dynamics simulations. We believe these findings have important implications for designing new anti-influenza drugs.

  19. Channeling your inner ear potassium: K(+) channels in vestibular hair cells.

    Science.gov (United States)

    Meredith, Frances L; Rennie, Katherine J

    2016-08-01

    During development of vestibular hair cells, K(+) conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K(+) channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low-voltage-activated K(+) current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K(+) currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K(+) channels contribute to the outward K(+) conductance and are present in varying proportions in HCII. In many species, K(+) currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K(+)-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed. This article is part of a Special Issue entitled . PMID:26836968

  20. Joint Source-Channel Coding over a Fading Multiple Access Channel with Partial Channel State Information

    CERN Document Server

    Rajesh, R

    2009-01-01

    In this paper we address the problem of transmission of correlated sources over a fast fading multiple access channel (MAC) with partial channel state information available at both the encoders and the decoder. We provide sufficient conditions for transmission with given distortions. Next these conditions are specialized to a Gaussian MAC (GMAC). We provide the optimal power allocation strategy and compare the strategy with various levels of channel state information. Keywords: Fading MAC, Power allocation, Partial channel state information, Correlated sources.

  1. Chemical Modification of Tryptophan Residues in Pullulanase

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Tryptophan(Trp)residues in pullulanase have been chemically modified with N-bromossuccinimide(NBS). The results of ultraviolet spectra indicated that there are 18 Trp residues in pullulanase and nine of them are located on the surface of the enzyme. Three of these Trp residues are none-essential residues which showed the fastest reaction speed by Zhou's plot. Two of the seven relative faster reacting residues are essential for the activity of the enzyme. The other eight are none-reactive residues with lowest reaction speed.

  2. Inactivation of the KcsA potassium channel explored with heterotetramers

    OpenAIRE

    Rotem, Dvir; Mason, Amy; Bayley, Hagan

    2010-01-01

    The tetrameric prokaryotic potassium channel KcsA is activated by protons acting on the intracellular aspect of the protein and inactivated through conformational changes in the selectivity filter. Inactivation is modulated by a network of interactions within each protomer between the pore helix and residues at the external entrance of the channel. Inactivation is suppressed by the E71A mutation, which perturbs the stability of this network. Here, cell-free protein synthesis followed by prote...

  3. Single channels of 9, 11, 13, 15-destryptophyl-phenylalanyl-gramicidin A.

    OpenAIRE

    Heitz, F.; Spach, G; Trudelle, Y

    1982-01-01

    Analysis of the single-channel behavior of an analogue of gramicidin A in which all four tryptophyl residues are substituted by phenylalanyl suggests that the nature of the side chains may play an important role in the ion translocation process. Indeed, while infrared spectroscopy indicates that both peptides have very similar backbone conformations, they have different single-channel characteristics. The unit conductance of the analogue is much smaller than that of the natural product. Moreo...

  4. Challenges of purchasing centralization : empirical evidence from public procurement

    OpenAIRE

    Karjalainen, Katri

    2009-01-01

    Centralization of purchasing activities is an escalating trend for both public and private organizations. Organizations are attempting to capture the economies of scale in purchasing prices and process costs by replacing individual purchases done throughout the organization with corporate-wide framework agreements. These benefits are achieved by the formalization of purchasing processes and channels, e.g. e-procurement, and the reduction in supplier base, developed by the central purchasing u...

  5. Targeting ion channels in cystic fibrosis.

    Science.gov (United States)

    Mall, Marcus A; Galietta, Luis J V

    2015-09-01

    Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause a characteristic defect in epithelial ion transport that plays a central role in the pathogenesis of cystic fibrosis (CF). Hence, pharmacological correction of this ion transport defect by targeting of mutant CFTR, or alternative ion channels that may compensate for CFTR dysfunction, has long been considered as an attractive approach to a causal therapy of this life-limiting disease. The recent introduction of the CFTR potentiator ivacaftor into the therapy of a subgroup of patients with specific CFTR mutations was a major milestone and enormous stimulus for seeking effective ion transport modulators for all patients with CF. In this review, we discuss recent breakthroughs and setbacks with CFTR modulators designed to rescue mutant CFTR including the common mutation F508del. Further, we examine the alternative chloride channels TMEM16A and SLC26A9, as well as the epithelial sodium channel ENaC as alternative targets in CF lung disease, which remains the major cause of morbidity and mortality in patients with CF. Finally, we will focus on the hurdles that still need to be overcome to make effective ion transport modulation therapies available for all patients with CF irrespective of their CFTR genotype. PMID:26115565

  6. The Cauchy method of residues

    CERN Document Server

    Mitrinović, Dragoslav S

    1993-01-01

    Volume 1, i. e. the monograph The Cauchy Method of Residues - Theory and Applications published by D. Reidel Publishing Company in 1984 is the only book that covers all known applications of the calculus of residues. They range from the theory of equations, theory of numbers, matrix analysis, evaluation of real definite integrals, summation of finite and infinite series, expansions of functions into infinite series and products, ordinary and partial differential equations, mathematical and theoretical physics, to the calculus of finite differences and difference equations. The appearance of Volume 1 was acknowledged by the mathematical community. Favourable reviews and many private communications encouraged the authors to continue their work, the result being the present book, Volume 2, a sequel to Volume 1. We mention that Volume 1 is a revised, extended and updated translation of the book Cauchyjev raeun ostataka sa primenama published in Serbian by Nau~na knjiga, Belgrade in 1978, whereas the greater part ...

  7. Residual intersections and some applications

    CERN Document Server

    Wu, X

    1994-01-01

    We give a new residual intersection decomposition for the refined intersection products of Fulton-MacPherson. Our formula refines the celebrated residual intersection formula of Fulton, Kleiman, Laksov, and MacPherson. The new decomposition is more likely to be compatible with the canonical decomposition of the intersection products and each term in the decomposition thus has simple geometric meaning. Our study is motivated by its applications to some geometric problems. In particular, we use the decomposition to find the distribution of limiting linear subspaces in degenerations of hypersurfaces. A family of identities for characteristic classes of vector bundles is also obtained as another consequence. This paper will appear in Duke Math. Jour.

  8. Molecular determinants of ATP-sensitive potassium channel MgATPase activity: diabetes risk variants and diazoxide sensitivity.

    Science.gov (United States)

    Fatehi, Mohammad; Carter, Chris R J; Youssef, Nermeen; Hunter, Beth E; Holt, Andrew; Light, Peter E

    2015-01-01

    ATP-sensitive K(+) (KATP) channels play an important role in insulin secretion. KATP channels possess intrinsic MgATPase activity that is important in regulating channel activity in response to metabolic changes, although the precise structural determinants are not clearly understood. Furthermore, the sulfonylurea receptor 1 (SUR1) S1369A diabetes risk variant increases MgATPase activity, but the molecular mechanisms remain to be determined. Therefore, we hypothesized that residue-residue interactions between 1369 and 1372, predicted from in silico modelling, influence MgATPase activity, as well as sensitivity to the clinically used drug diazoxide that is known to increase MgATPase activity. We employed a point mutagenic approach with patch-clamp and direct biochemical assays to determine interaction between residues 1369 and 1372. Mutations in residues 1369 and 1372 predicted to decrease the residue interaction elicited a significant increase in MgATPase activity, whereas mutations predicted to possess similar residue interactions to wild-type (WT) channels elicited no alterations in MgATPase activity. In contrast, mutations that were predicted to increase residue interactions resulted in significant decreases in MgATPase activity. We also determined that a single S1369K substitution in SUR1 caused MgATPase activity and diazoxide pharmacological profiles to resemble those of channels containing the SUR2A subunit isoform. Our results provide evidence, at the single residue level, for a molecular mechanism that may underlie the association of the S1369A variant with type 2 diabetes. We also show a single amino acid difference can account for the markedly different diazoxide sensitivities between channels containing either the SUR1 or SUR2A subunit isoforms. PMID:26181369

  9. Marketing Strategy of Pay Channels

    Directory of Open Access Journals (Sweden)

    Fanbin Zeng

    2012-12-01

    Full Text Available Pay Channels not only need to improve the quality of their content, but also need to focus on marketing strategy. To develop Pay Channels in China, we not only need to improve the content of the TV programs, but also need to focus on the marketing strategy. So far, we have two main approaches of marketing in China. One is being operated by integration platform; the other is by the Channel itself. Pay channels are not developed so well in China. In this paper, we are going to discuss on the existing problems of pay channels in China and try to find out the effective ways to carry out marketing strategy of pay channels. To improve the situation of pay channels in China, we might take the following measures: 1 Pursue different kinds of sales approach. 2 Provide Free Preview to Expand the Scope of Publicity. 3 Lower charging fee. 4 Establish a perfect customer service system.

  10. Feedback Power Control Strategies inWireless Sensor Networks with Joint Channel Decoding

    Directory of Open Access Journals (Sweden)

    Fabio Perna

    2009-11-01

    Full Text Available In this paper, we derive feedback power control strategies for block-faded multiple access schemes with correlated sources and joint channel decoding (JCD. In particular, upon the derivation of the feasible signal-to-noise ratio (SNR region for the considered multiple access schemes, i.e., the multidimensional SNR region where error-free communications are, in principle, possible, two feedback power control strategies are proposed: (i a classical feedback power control strategy, which aims at equalizing all link SNRs at the access point (AP, and (ii an innovative optimized feedback power control strategy, which tries to make the network operational point fall in the feasible SNR region at the lowest overall transmit energy consumption. These strategies will be referred to as “balanced SNR” and “unbalanced SNR,” respectively. While they require, in principle, an unlimited power control range at the sources, we also propose practical versions with a limited power control range. We preliminary consider a scenario with orthogonal links and ideal feedback. Then, we analyze the robustness of the proposed power control strategies to possible non-idealities, in terms of residual multiple access interference and noisy feedback channels. Finally, we successfully apply the proposed feedback power control strategies to a limiting case of the class of considered multiple access schemes, namely a central estimating officer (CEO scenario, where the sensors observe noisy versions of a common binary information sequence and the AP’s goal is to estimate this sequence by properly fusing the soft-output information output by the JCD algorithm.

  11. Calcination/dissolution residue treatment

    International Nuclear Information System (INIS)

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination

  12. Residual activity criteria for decommissioning

    International Nuclear Information System (INIS)

    The U.S. Nuclear Regulatory Commission development of criteria for release of facilities and sites for unrestricted use following decommissioning is described. Residual activity limits for both materials and soil are covered. The objectives are: small risk of exposure, consistency with relevant existing standards, and feasibility of demonstration of compliance by measurement. Specific aspects discussed related to establishment of limits are: appropriate risk and dose limits, identification of radionuclides to be considered, dose assessment methodology, and confirmatory measurements

  13. Wiretap Channel with Action-Dependent Channel State Information

    Directory of Open Access Journals (Sweden)

    Bin Dai

    2013-01-01

    Full Text Available In this paper, we investigate the model of wiretap channel with action-dependent channel state information. Given the message to be communicated, the transmitter chooses an action sequence that affects the formation of the channel states, and then generates the channel input sequence based on the state sequence and the message. The main channel and the wiretap channel are two discrete memoryless channels (DMCs, and they are connected with the legitimate receiver and the wiretapper, respectively. Moreover, the transition probability distribution of the main channel depends on the channel state. Measuring wiretapper’s uncertainty about the message by equivocation, inner and outer bounds on the capacity-equivocation region are provided both for the case where the channel inputs are allowed to depend non-causally on the state sequence and the case where they are restricted to causal dependence. Furthermore, the secrecy capacities for both cases are bounded, which provide the best transmission rate with perfect secrecy. The result is further explained via a binary example.

  14. Entrance channel influence on the formation and decay of hot nuclei

    International Nuclear Information System (INIS)

    Different entrance channels have been investigated to form very hot nuclei and to study their decay properties. i) Argon and Nickel projectiles accelerated around the Fermi energy show that central collisions induce momentum transfers to target nuclei which are proportional to the mass of the projectile and not to its velocities in the studied energy range. The preequilibrium model fits nicely the experimental results. The decay properties of the fission products for hot nuclei will be presented. Both head-on collisions and peripheral massive transfers contribute to the formation of very excited nuclei. The question of the influence of the energy deposit in the composite like system in limiting their yields is discussed. ii) Investigations have been also achieved with alpha projectiles at much higher incident energy (around 1 GeV/u). It is shown that hot and thermalized nuclei are also formed even when the nucleon-nucleon collisions are predominant. A sensitive parameter of the transition from binary fission to multifragmentation seems to be the energy deposit in the target residues rather than the projectile velocity

  15. Geotechnical characteristics of residual soils

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, F.C.

    1985-01-01

    Residual soils are products of chemical weathering and thus their characteristics are dependent upon environmental factors of climate, parent material, topography and drainage, and age. These conditions are optimized in the tropics where well-drained regions produce reddish lateritic soils rich in iron and aluminum sesquioxides and kaolinitic clays. Conversely, poorly drained areas tend towards montmorillonitic expansive black clays. Andosols develop over volcanic ash and rock regions and are rich in allophane (amorphous silica) and metastable halloysite. The geological origins greatly affect the resulting engineering characteristics. Both lateritic soils and andosols are susceptible to property changes upon drying, and exhibit compaction and strength properties not indicative of their classification limits. Both soils have been used successfully in earth dam construction, but attention must be given to seepage control through the weathered rock. Conversely, black soils are unpopular for embankments. Lateritic soils respond to cement stabilization and, in some cases, lime stabilization. Andosols should also respond to lime treatment and cement treatments if proper mixing can be achieved. Black expansive residual soils respond to lime treatment by demonstrating strength gains and decreased expansiveness. Rainfall induced landslides are typical of residual soil deposits.

  16. Evaluation of residue drum storage safety risks

    International Nuclear Information System (INIS)

    A study was conducted to determine if any potential safety problems exist in the residue drum backlog at the Rocky Flats Plant. Plutonium residues stored in 55-gallon drums were packaged for short-term storage until the residues could be processed for plutonium recovery. These residues have now been determined by the Department of Energy to be waste materials, and the residues will remain in storage until plans for disposal of the material can be developed. The packaging configurations which were safe for short-term storage may not be safe for long-term storage. Interviews with Rocky Flats personnel involved with packaging the residues reveal that more than one packaging configuration was used for some of the residues. A tabulation of packaging configurations was developed based on the information obtained from the interviews. A number of potential safety problems were identified during this study, including hydrogen generation from some residues and residue packaging materials, contamination containment loss, metal residue packaging container corrosion, and pyrophoric plutonium compound formation. Risk factors were developed for evaluating the risk potential of the various residue categories, and the residues in storage at Rocky Flats were ranked by risk potential. Preliminary drum head space gas sampling studies have demonstrated the potential for formation of flammable hydrogen-oxygen mixtures in some residue drums

  17. QKD Quantum Channel Authentication

    OpenAIRE

    Kosloski, J. T.

    2006-01-01

    Several simple yet secure protocols to authenticate the quantum channel of various QKD schemes, by coupling the photon sender's knowledge of a shared secret and the QBER Bob observes, are presented. It is shown that Alice can encrypt certain portions of the information needed for the QKD protocols, using a sequence whose security is based on computational-complexity, without compromising all of the sequence's entropy. It is then shown that after a Man-in-the-Middle attack on the quantum and c...

  18. The determination of residual stress by means of neutron diffraction

    International Nuclear Information System (INIS)

    Very recently a new, dedicated, state-of-the-art diffractometer has been installed at the NIST reactor. With it, the residual stress fields in bent steel tubes have been mapped. Two mild steel tubes, of outside diameter 168 mm, wall thickness 8 mm and length 1,000 mm, were subjected to four-point bends. Tube 1 is seamless, tube 2 has a weld parallel to the cylindrical axis. After bending, the central 260 mm, together with end pieces, were cut out of the tubes for neutron diffraction measurements. Using a 2x2x2 mm3 gauge volume, strain components were measured as a function of depth beneath the surface at various locations along the axis and around the circumference of the tubes. Residual stresses were inferred from the measured strains by utilizing Hooke's Law and the appropriate diffraction elastic constants. Features of the new instrument and various experimental results will be discussed

  19. Mantle dynamics and Cretaceous magmatism in east-central China: Insight from teleseismic tomograms

    Science.gov (United States)

    Jiang, Guoming; Zhang, Guibin; Zhao, Dapeng; Lü, Qingtian; Li, Hongyi; Li, Xinfu

    2015-11-01

    Both the rich mineralization in the Lower Yangtze Block (LYB) and the post-collisional mafic rocks in the Dabie Orogen (DBO) are closely related to the Cretaceous magmatism in east-central China. Various geodynamic models have been proposed for explaining the mechanism of the Cretaceous magmatism, but these models are controversial and even contradictory with each other, especially on the mechanism of adakites. A unified geodynamic model is required for explaining the magmatism in east-central China, in particular, the spatial and temporal correlations of magmatic activity in the DBO and that in the LYB. For this purpose, we apply teleseismic tomography to study P-wave velocity structure down to 800 km depth beneath east-central China. A modified multiple-channel cross-correlation method is used to collect 28,805 high-quality P-wave arrival-time data from seismograms of distant earthquakes recorded by permanent seismic stations and our temporary stations in the study region. To remove the influence of crustal heterogeneity on the mantle tomography, we used the CRUST1.0 model to correct the teleseismic relative residuals. Our tomography revealed distinct high-velocity (high-V) anomalies beneath the DBO and two flanks of the LYB, and low-velocity (low-V) anomalies above the high-V zones. Combining our tomographic images with previous geological, geochemical and geophysical results, we infer that these high-V and low-V anomalies reflect the detached lithosphere and upwelling asthenospheric materials, respectively, which are associated with the Late Mesozoic dynamic process and the Cretaceous magmatism. We propose a double-slab subduction model that a ridge subduction yielded the adakitic rocks in the LYB during 150-135 Ma and the subsequent Pacific Plate subduction played a crucial role in not only the formation of igneous rocks in the LYB but also remelting of the subducted South China Block beneath the DBO during 135-101 Ma.

  20. Evaluation of residue management practices effects on corn productivity, soil quality, and greenhouse gas emissions

    Science.gov (United States)

    Guzman, Jose German

    The removal of crop residues left after harvest is being considered as a potential feedstock source for bioethanol production which can contribute to the reduction of fossil fuel use and net greenhouse gas (GHG). The objectives of this study were to: (i) examine how tillage, N fertilization rates, residue removal, and their interactions affect crop productivity, (ii) SOC and soil physical properties, and (iii) GHG emissions, and (iv) calculated a soil C budget to determine how much crop residue can be sustainably be removed in Central and Southwest Iowa. After three years of residue removal under different management practices, the findings of this study suggest that a portion of the corn residue that is left on the soil surface after harvest can be removed, with no negative impacts in the short term continuous corn yield in sites at Central and Southwest Iowa. However, significant decreases in SOC sequestration rates, microbial biomass-C, bulk density, soil penetration resistance, wet aggregate stability, and infiltration rates were observed, but varied with soil type and management practices. Additionally, soil surface CO2 and N2O emissions were responsive to management practices; primarily by altering soil temperature, soil water content, soil mineral N, and crop growth. Results from soil C budget show that in 2010 when corn growth was not water stressed (lack of moisture), approximately 35 and 30% of the residue could be sustainably removed in the Central and Southwest sites, respectively. In 2011, drier soil conditions resulted in approximately 2 and 49% of the residue could be sustainably removed in the Central and Southwest sites, respectively.

  1. Polychlorinated Biphenyls (PCB) Residue Effects Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic...

  2. Improving virtual channel discrimination in a multi-channel context.

    Science.gov (United States)

    Srinivasan, Arthi G; Shannon, Robert V; Landsberger, David M

    2012-04-01

    Improving spectral resolution in cochlear implants is key to improving performance in difficult listening conditions (e.g. speech in noise, music, etc.). Current focusing might reduce channel interaction, thereby increasing spectral resolution. Previous studies have shown that combining current steering and current focusing reduces spread of excitation and improves virtual channel discrimination in a single-channel context. It is unclear whether the single-channel benefits from current focusing extend to a multi-channel context, in which the physical and perceptual interference of multiple stimulated channels might overwhelm the benefits of improved spectral resolution. In this study, signal discrimination was measured with and without current focusing, in the presence of competing stimuli on nearby electrodes. Results showed that signal discrimination was consistently better with current focusing than without, regardless of the amplitude of the competing stimuli. Therefore, combining current steering and current focusing may provide more effective spectral cues than are currently available. PMID:22616092

  3. EFFICIENT UTILIZATION OF CHANNELS USING DYNAMIC GUARD CHANNEL ALLOCATION WITH CHANNEL BORROWING STRATEGY IN HANDOFFS

    Directory of Open Access Journals (Sweden)

    Alagu S

    2012-05-01

    Full Text Available User mobility in wireless data networks is increasing because of technological advances and the desire for voice and multimedia applications. These applications, however, require fast handoffs between base stations to maintain the quality of the connections. In this paper, the authors describe the use of novel and efficient data structure which dynamically allocates guard channel for handoffs and introduces the concept of channel borrowing strategy. The proposed scheme allocates the guard channels for handoff requests dynamically, based on the traffic load for certain time period. A new originating call in the cell coverage area also uses these guard channels if they are unused. Our basic idea is to allow Guard channels to be shared between new calls and handoff calls. This approach maximizes the channel utilization. The simulation results prove that the channel borrowing scheme improves the overall throughput.

  4. Two temporal channels in human V1 identified using fMRI.

    Science.gov (United States)

    Horiguchi, Hiroshi; Nakadomari, Satoshi; Misaki, Masaya; Wandell, Brian A

    2009-08-01

    Human visual sensitivity to a fairly broad class of dynamic stimuli can be modeled accurately using two temporal channels. Here, we analyze fMRI measurements of the temporal step response to spatially uniform stimuli to estimate these channels in human primary visual cortex (V1). In agreement with the psychophysical literature, the V1 fMRI temporal responses are modeled accurately as a mixture of two (transient and sustained) channels. We derive estimates of the relative contributions from these two channels at a range of eccentricities. We find that all portions of V1 contain a significant transient response. The central visual field representation includes a significant sustained response, but the amplitude of the sustained channel signal declines with eccentricity. The sustained signals may reflect the emphasis on pattern recognition and color in the central visual field; the dominant transient response in the visual periphery may reflect responses in the human visual attention system. PMID:19361561

  5. Effect of welding residual stresson fracture

    OpenAIRE

    Ren, Xiaobo

    2010-01-01

    Residual stresses are unavoidable in welded constructions. How to correctly predict residual stresses and assess their effect on structural integrity is a fundamental issue. One of the most difficult aspects in structural integrity assessment is to incorporate the effect of residual stresses in a safe manner, without making unduly conservative assumptions about the level of stress that may be present. Current structural assessment procedures typically assume upper bound residual stress soluti...

  6. Packing channels with hydroinsulating ash pitchings

    Energy Technology Data Exchange (ETDEWEB)

    Nowakowa, J.

    1982-01-01

    The paper evaluates utilizatiion of fly ash from fossil-fuel power plants for production of panels used as pitching of channels and other water constructions. Two ash types were used: from the Konin plant fired with brown coal and from the Elblag plant fired with black coal. Three panel types were evaluated: fly ash from brown coal and 5% waterglass; fly ash from black coal, 6% waste products from sulfur filtration and 10% waterglass; ash from black coal, 6% carbide residue and 10% waterglass. Physical properties of three panel types such as filtration properties, compression strength, water influence and selected chemical properties (toxicity caused by the presence of activating compounds) were analyzed. Grass growth rate on ash panel pitching was observed 12 months long under laboratory conditions. Investigations show that grass growth rate was higher when brown coal ash was used. Water filtration improved grass vegetation in comparison to grass growth on dry ash panels only influenced by atmospheric precipitations. Grass roots did not penetrate ash pitching but formed a protective cover on panel surface. Use of channel pitching made of fly ash, waterglass and activating reagents is recommended. (13 refs.)

  7. Three-dimensional plume simulation of multi-channel thruster configuration

    International Nuclear Information System (INIS)

    A three-dimensional hybrid particle-in-cell model of the plume emitted by a four-channel Hall-effect thruster configuration for a preliminary design study has been developed. Results show the presence of a potential well in the central region close to the exit plane of the configuration. Together with the typical characteristics of the single channel ion energy spectrum, a double peak structure in the low energy range is present in the four-channel configuration. It is due to the geometrical effects (four-channel source) and to the anisotropic nature of ion–atom scattering. (paper)

  8. DMT of weighted Parallel Channels: Application to Broadcast Channel

    OpenAIRE

    Mroueh, Lina; Rouquette-Léveil, Stéphanie; Othman, Ghaya Rekaya-Ben; Belfiore, Jean-Claude

    2008-01-01

    In a broadcast channel with random packet arrival and transmission queues, the stability of the system is achieved by maximizing a weighted sum rate capacity with suitable weights that depend on the queue size. The weighted sum rate capacity using Dirty Paper Coding (DPC) and Zero Forcing (ZF) is asymptotically equivalent to the weighted sum capacity over parallel single-channels. In this paper, we study the Diversity Multiplexing Tradeoff (DMT) of the fading broadcast channel under a fixed w...

  9. Chunnel vision: Export and efflux through bacterial channel-tunnels

    OpenAIRE

    Andersen, Christian; Hughes, Colin; Koronakis, Vassilis

    2000-01-01

    The Escherichia coli TolC protein is central to toxin export and drug efflux across the inner and outer cell membranes and the intervening periplasmic space. The crystal structure has revealed that TolC assembles into a remarkable α-helical trans-periplasmic cylinder (tunnel) embedded in the outer membrane by a contiguous β-barrel (channel), so providing a large duct open to the outside environment. The channel-tunnel structure is conserved in TolC homologues throughout Gram-negative bacteria...

  10. Ion Channels and Zinc: Mechanisms of Neurotoxicity and Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Deborah R. Morris

    2012-01-01

    Full Text Available Ionotropic glutamate receptors, such as NMDA, AMPA and kainate receptors, are ligand-gated ion channels that mediate much of the excitatory neurotransmission in the brain. Not only do these receptors bind glutamate, but they are also regulated by and facilitate the postsynaptic uptake of the trace metal zinc. This paper discusses the role of the excitotoxic influx and accumulation of zinc, the mechanisms responsible for its cytotoxicity, and a number of disorders of the central nervous system that have been linked to these neuronal ion channels and zinc toxicity including ischemic brain injury, traumatic brain injury, and epilepsy.

  11. CENTRAL ASIA'S POWER DILEMMAS

    OpenAIRE

    Budkin, Viktor

    2006-01-01

    It turned out to be much harder to create new power structures in Central Asia than elsewhere in the post-socialist world: no matter how hard it was for the Central European countries to acquire new political institutions, their advance toward the Western democratic model was much smoother. In the European part of the post-Soviet geopolitical expanse, Russia, Ukraine, and Moldova experienced fewer problems than the Central Asian region (CAR for short), though they too had their share of contr...

  12. A Micromechanical RF Channelizer

    Science.gov (United States)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  13. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initi...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  14. Management of post-harvest residue blanket

    Science.gov (United States)

    Timely and effective residue management is essential for maximum sugar yields. Several studies were implemented in 2003 and harvested in 2004 in an effort to increase the effectiveness of residue management practices. Six studies were conducted to determine the effect of residue removal timing a...

  15. 9 CFR 311.39 - Biological residues.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues....

  16. Transitive parallelism of residues in buildings

    OpenAIRE

    Clais, Antoine

    2013-01-01

    We study the buildings in which parallelism of residues is an equivalence relation. If the building admits a group action, we describe how parallel residues are related to residues with equal stabilizers. This permits to retrieve the fact that in a Coxeter group or in a graph product, intersections of parabolic subgroups are parabolic.

  17. Central Laboratories Services

    Data.gov (United States)

    Federal Laboratory Consortium — The TVA Central Laboratories Services is a comprehensive technical support center, offering you a complete range of scientific, engineering, and technical services....

  18. Energy-Efficient Channel Handoff for Sensor Network-Assisted Cognitive Radio Network.

    Science.gov (United States)

    Usman, Muhammad; Khan, Muhammad Sajjad; Vu-Van, Hiep; Insoo, Koo

    2015-01-01

    The visiting and less-privileged status of the secondary users (SUs) in a cognitive radio network obligates them to release the occupied channel instantly when it is reclaimed by the primary user. The SU has a choice to make: either wait for the channel to become free, thus conserving energy at the expense of delayed transmission and delivery, or find and switch to a vacant channel, thereby avoiding delay in transmission at the expense of increased energy consumption. An energy-efficient decision that considers the tradeoff between energy consumption and continuous transmission needs to be taken as to whether to switch the channels. In this work, we consider a sensor network-assisted cognitive radio network and propose a backup channel, which is sensed by the SU in parallel with the operating channel that is being sensed by the sensor nodes. Imperfect channel sensing and residual energy of the SU are considered in order to develop an energy-efficient handoff strategy using the partially observable Markov decision process (POMDP), which considers beliefs about the operating and backup channels and the remaining energy of the SU in order to take an optimal channel handoff decision on the question "Should we switch the channel?" The objective is to dynamically decide in each time slot whether the SU should switch the channel or not in order to maximize throughput by utilizing energy efficiently. Extensive simulations were performed to show the effectiveness of the proposed channel handoff strategy, which was demonstrated in the form of throughput with respect to various parameters, i.e., detection probability, the channel idle probabilities of the operating and backup channels, and the maximum energy of the SU. PMID:26213936

  19. Energy-Efficient Channel Handoff for Sensor Network-Assisted Cognitive Radio Network

    Directory of Open Access Journals (Sweden)

    Muhammad Usman

    2015-07-01

    Full Text Available The visiting and less-privileged status of the secondary users (SUs in a cognitive radio network obligates them to release the occupied channel instantly when it is reclaimed by the primary user. The SU has a choice to make: either wait for the channel to become free, thus conserving energy at the expense of delayed transmission and delivery, or find and switch to a vacant channel, thereby avoiding delay in transmission at the expense of increased energy consumption. An energy-efficient decision that considers the tradeoff between energy consumption and continuous transmission needs to be taken as to whether to switch the channels. In this work, we consider a sensor network-assisted cognitive radio network and propose a backup channel, which is sensed by the SU in parallel with the operating channel that is being sensed by the sensor nodes. Imperfect channel sensing and residual energy of the SU are considered in order to develop an energy-efficient handoff strategy using the partially observable Markov decision process (POMDP, which considers beliefs about the operating and backup channels and the remaining energy of the SU in order to take an optimal channel handoff decision on the question “Should we switch the channel?” The objective is to dynamically decide in each time slot whether the SU should switch the channel or not in order to maximize throughput by utilizing energy efficiently. Extensive simulations were performed to show the effectiveness of the proposed channel handoff strategy, which was demonstrated in the form of throughput with respect to various parameters, i.e., detection probability, the channel idle probabilities of the operating and backup channels, and the maximum energy of the SU.

  20. Mechanism of electromechanical coupling in voltage-gated potassium channels

    Directory of Open Access Journals (Sweden)

    RikardBlunck

    2012-09-01

    Full Text Available Voltage-gated ion channels play a central role in the generation of action potentials in the nervous system. They are selective for one type of ion – sodium, calcium or potassium. Voltage-gated ion channels are composed of a central pore that allows ions to pass through the membrane and four peripheral voltage sensing domains that respond to changes in the membrane potential. Upon depolarization, voltage sensors in voltage-gated potassium channels (Kv undergo conformational changes driven by positive charges in the S4 segment and aided by pairwise electrostatic interactions with the surrounding voltage sensor. Structure-function relations of Kv channels have been investigated in detail, and the resulting models on the movement of the voltage sensors now converge to a consensus; the S4 segment undergoes a combined movement of rotation, tilt and vertical displacement in order to bring 3-4 e+ each through the electric field focused in this region. Nevertheless, the mechanism by which the voltage sensor movement leads to pore opening, the electromechanical coupling, is still not fully understood. Thus, recently, electromechanical coupling in different Kv channels has been investigated with a multitude of techniques including electrophysiology, 3D crystal structures, fluorescence spectroscopy and molecular dynamics simulations. Evidently, the S4-S5 linker, the covalent link between the voltage sensor and pore, plays a crucial role. The linker transfers the energy from the voltage sensor movement to the pore domain via an interaction with the S6 C-termini, which are pulled open during gating. In addition, other contact regions have been proposed. This review aims to provide (i an in-depth comparison of the molecular mechanisms of electromechanical coupling in different Kv channels; (ii insight as to how the voltage sensor and pore domain influence one another; and (iii theoretical predictions on the movement of the cytosolic face of the KV channels

  1. Residual gauge fixing in light-front QCD

    CERN Document Server

    Zhang, W M; Zhang, Wei-Min; Harindranth, Avaroth

    1993-01-01

    Understanding the nontrivial features of light-front QCD is a central goal in current investigations of nonperturbative light-front field theory. We find that, with the choice of light-front gauge with antisymmetric boundary conditions for the field variables, the residual gauge freedom is fixed and the light-front QCD vacuum is trivial. The nontrivial structure in light-front QCD is determined by non-vanishing asymptotic physical (transverse) gauge fields at longitudinal infinity, which are responsible for nonzero topological winding number.

  2. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Enhancement of water permeation across nanochannels by partial charges mimicked from biological channels

    Science.gov (United States)

    Gong, Xiao-Jing; Fang, Hai-Ping

    2008-07-01

    In biological water channel aquaporins (AQPs), it is believed that the bipolar orientation of the single-file water molecules inside the channel blocks proton permeation but not water transport. In this paper, the water permeation and particularly the water-selective behaviour across a single-walled carbon nanotube (SWNT) with two partial charges adjacent to the wall of the SWNT are studied by molecular dynamics simulations, in which the distance between the two partial charges is varied from 0.14 nm to 0.5 nm and the charges each have a quantity of 0.5 e. The two partial charges are used to mimic the charge distribution of the conserved non-pseudoautosomal (NPA) (asparagine/proline/alanine) regions in AQPs. Compared with across the nanochannel in a system with one +1 e charge, the water permeation across the nanochannel is greatly enhanced in a system with two +0.5 e charges when charges are close to the nanotube, i.e. the two partial charges permit more rapid water diffusion and maintain better bipolar order along the water file when the distance between the two charges and the wall of SWNT is smaller than about 0.05 nm. The bipolar orientation of the single-file water molecules is crucial for the exclusion of proton transfer. These findings may serve as guidelines for the future nanodevices by using charges to transport water and have biological implications because membrane water channels share a similar single-file water chain and positive charged region at centre and provide an insight into why two residues are necessitated in the central region of water channel protein.

  3. Biomass energy in Central America

    International Nuclear Information System (INIS)

    The objective of this paper is to introduce the concept of biomass to energy issues and opportunities in Central America. In this region, made up of seven countries (Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and Panama), the biomass sector has the potential to play a crucial role in alleviating the environmental and development predicaments faced by all economies of the region. This paper assesses the available biomass resources at the regional and country levels and gives an overview of the current utilization of biomass fuels. It also describes the overall context in which the biomass-to-energy initiatives are immersed. At the regional level, biomass energy consumption accounts for more than 50% of total energy consumption. In regard to the utilization of biomass for energy purposes, it is clear that Central America faces a critical juncture at two levels, both mainly in rural areas: in the productive sector and at the household level. The absence of sustainable development policies and practices has jeopardized the availability of biomass fuels, particularly wood. Firewood is an important source of energy for rural industries such as coffee processing, which is one of the largest productive activities in the region. This paper comments on some of the most successful technological innovations already in place in the region, for instance, the rapid development of co-generation projects by the sugar cane industry, especially in El Salvador and Guatemala, the substitution of coffee husks for firewood in coffee processing plants in Costa Rica and El Salvador and the sustainable use of pine forests for co-generation in Honduras. Only one out of every two inhabitants in Central America now has access to electricity from the public grid. Biomass fuels, mainly firewood but also, to a lesser extent, other crop residues such as corn stalks, are the main source of energy for cooking and heating by most of the population. (It is foreseen that by the end

  4. Natural radioactivity in petroleum residues

    International Nuclear Information System (INIS)

    The oil extraction and production industry generates several types of solid and liquid wastes. Scales, sludge and water are typical residues that can be found in such facilities and that can be contaminated with Naturally Occurring Radioactive Material (N.O.R.M.). As a result of oil processing, the natural radionuclides can be concentrated in such residues, forming the so called Technologically Enhanced Naturally Occurring Radioactive Material, or T.E.N.O.R.M.. Most of the radionuclides that appear in oil and gas streams belong to the 238U and 232Th natural series, besides 40 K. The present work was developed to determine the radionuclide content of scales and sludge generated during oil extraction and production operations. Emphasis was given to the quantification of 226Ra, 228Ra and 40 K since these radionuclides,are responsible for most of the external exposure in such facilities. Samples were taken from the P.E.T.R.O.B.R.A.S. unity in the State of Sergipe, in Northeastern Brazil. They were collected directly from the inner surface of water pipes and storage tanks, or from barrels stored in the waste storage area of the E and P unit. The activity concentrations for 226Ra, 228Ra and 40 K were determined by using an HP Ge gamma spectrometric system. The results showed concentrations ranging from 42.7 to 2,110.0 kBq/kg for 226Ra, 40.5 to 1,550.0 kBq/kg for 228Ra, and 20.6 to 186.6 kBq/kg for 40 K. The results highlight the importance of determining the activity concentration of those radionuclides in oil residues before deciding whether they should be stored or discarded to the environment. (authors)

  5. Analysis of OFDM System using Pilot Channel Estimation

    Directory of Open Access Journals (Sweden)

    Amit

    2012-04-01

    Full Text Available Orthogonal Frequency Division Multiplexing (OFDM ismultiplexing technology of orthogonal multicarrier, and thechannel estimation model based on pilot in OFDM systemsis analyzed; Now that, the channel estimation based onpilot needs interpolation, in order to reduce the complexityof the interpolation algorithm, the FFT channel estimationalgorithm based on pilot is studied. Because of the directFFT channel estimation algorithm existing energy spectrumleakage problems, the optimized FFT channel estimationalgorithm based on the Hamming windowed function is putforward. A lot of conventional algorithms have tried tocancel the residual frame synchronization error (RFSE,which causes the performance degradation of channelestimation when using interpolation between pilot subcarriersin comb-type pilot-aided OFDM systems.Orthogonal frequency-division multiplexing (OFDM is atransmission technique that is based on many orthogonalcarriers that are transmitted simultaneously. Channelestimation techniques for OFDM systems, based on combtypepilot arrangement, over frequency-selective Rican andtime-varying fading channel are investigated. Theadvantage of comb-type pilot arrangement, in channelestimation, is the ability to track the variation in thechannel, which is the main reason for inter-carrierinterference modeled as an additive white Gaussian noise,leading to an increase in the noise level.

  6. Process to recycle shredder residue

    Science.gov (United States)

    Jody, Bassam J.; Daniels, Edward J.; Bonsignore, Patrick V.

    2001-01-01

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  7. A STUDY OF RESIDUAL STRENGTH OF SISAL TEXTILE REINFORCED VINYL ESTER

    Institute of Scientific and Technical Information of China (English)

    Li Yan

    2005-01-01

    In this study, the residual strength of sisal textile reinforced vinyl ester resin is studied using specimens with a central hole. Two kinds of chemicals, silane and permanganate, are used to treat sisal fibre surfaces. The effects of fibre surface treatments on the residual strength of sisal fibre reinforced composites with different central hole sizes are analysed. Optical microscopy (OM) surveys provide sound evidence for the relationship between residual strength properties and fracture morphologies of sisal textile reinforced vinyl ester.Several theoretical models used to predict the residual strength of laminated composites are briefly reviewed. Point stress criterion (PSC) and average stress criterion (ASC) models are used to analyze the mechanical properties of sisal textile reinforced polymers with a central hole in this research. Material constant, characteristic length (do or lc), is obtained and used to analyze the mechanical behavior of the composites. The residual strength of the composites predicted by PSC and ASC models is in good agreement with the experimental results..

  8. Secure refinements of communication channels

    OpenAIRE

    Cheval, Vincent; Cortier, Véronique; Le Morvan, Eric

    2015-01-01

    International audience It is a common practice to design a protocol (say Q) assuming some secure channels. Then the secure channels are implemented using any standard protocol, e.g. TLS. In this paper, we study when such a practice is indeed secure. We provide a characterization of both confidential and authenticated channels. As an application, we study several protocols of the literature including TLS and BAC protocols. Thanks to our result, we can consider a larger number of sessions wh...

  9. Gramicidin Channels Are Internally Gated

    OpenAIRE

    Jones, Tyson L.; Fu, Riqiang; Nielson, Frederick; Cross, Timothy A.; Busath, David D

    2010-01-01

    Gramicidin channels are archetypal molecular subjects for solid-state NMR studies and investigations of single-channel or cation conductance. Until now, the transitions between on and off conductance states have been thought, based on multichannel studies, to represent monomer ↔ dimer reactions. Here we use a single-molecule deposition method (vesicle fusion to a planar bilayer) to show that gramicidin dimer channels do not normally dissociate when conductance terminates. Furthermore, the obs...

  10. Determining nitrogen laser channel parameters

    International Nuclear Information System (INIS)

    This paper reports the measurement of the nitrogen laser channel current using a magnetic probe. For a 46 cm laser channel of gap 16 mm operated at 10 kV, 60 torr with foil capacitors of 58 and 28 nF, the channel current, inductance and resistance are found to be 42 kA, l.6 nH and 0.1 Ω respectively. (author)

  11. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  12. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  13. Seasonal Changes in Central England Temperatures

    DEFF Research Database (Denmark)

    Proietti, Tommaso; Hillebrand, Eric

    deterministic and stochastic trends, as well as seasonally varying autocorrelation and residual variances. The model can be summarized as containing a permanent and a transitory component, where global warming is captured in the permanent component, on which the seasons load differentially. The phase of the......The aim of this paper is to assess how climate change is reflected in the variation of the seasonal patterns of the monthly Central England Temperature time series between 1772 and 2013. In particular, we model changes in the amplitude and phase of the seasonal cycle. Starting from the seminal work...

  14. Marte Vallis Channel

    Science.gov (United States)

    2004-01-01

    14 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a channel in the Marte Valles outflow system. An old meteor impact crater in the lower left (southwest) corner of the image blocked the erosive fluids that poured through Marte Vallis, creating a streamlined tail in its lee. The materials that flowed through the valley may have been water-rich mud, very fluid lava, or both. The nature of the fluid is still a matter of research and discussion among Mars scientists. This image is located near 12.5oN, 177.5oW. The image covers an area approximately 3 km (1.9 mi) across and is illuminated by sunlight from the left/lower left.

  15. Flag flapping in a channel

    Science.gov (United States)

    Alben, Silas; Shoele, Kourosh; Mittal, Rajat; Jha, Sourabh; Glezer, Ari

    2015-11-01

    We study the flapping of a flag in an inviscid channel flow. We focus especially on how quantities vary with channel spacing. As the channel walls move inwards towards the flag, heavier flags become more unstable, while light flags' stability is less affected. We use a vortex sheet model to compute large-amplitude flapping, and find that the flag undergoes a series of jumps to higher flapping modes as the channel walls are moved towards the flag. Meanwhile, the drag on the flag and the energy lost to the wake first rise as the walls become closer, then drop sharply as the flag moves to a higher flapping mode.

  16. Demystifying Mechanosensitive Piezo Ion Channels.

    Science.gov (United States)

    Xu, X Z Shawn

    2016-06-01

    Mechanosensitive channels mediate touch, hearing, proprioception, and blood pressure regulation. Piezo proteins, including Piezo1 and Piezo2, represent a new class of mechanosensitive channels that have been reported to play key roles in most, if not all, of these modalities. The structural architecture and molecular mechanisms by which Piezos act as mechanosensitive channels, however, remain mysterious. Two new studies have now provided critical insights into the atomic structure and molecular basis of the ion permeation and mechano-gating properties of the Piezo1 channel. PMID:27164907

  17. Geometric pumping in autophoretic channels

    CERN Document Server

    Michelin, Sebastien; De Canio, Gabriele; Lobato-Dauzier, Nicolas; Lauga, Eric

    2015-01-01

    Many microfluidic devices use macroscopic pressure differentials to overcome viscous friction and generate flows in microchannels. In this work, we investigate how the chemical and geometric properties of the channel walls can drive a net flow by exploiting the autophoretic slip flows induced along active walls by local concentration gradients of a solute species. We show that chemical patterning of the wall is not required to generate and control a net flux within the channel, rather channel geometry alone is sufficient. Using numerical simulations, we determine how geometric characteristics of the wall influence channel flow rate, and confirm our results analytically in the asymptotic limit of lubrication theory.

  18. Biophysics of BK Channel Gating.

    Science.gov (United States)

    Pantazis, A; Olcese, R

    2016-01-01

    BK channels are universal regulators of cell excitability, given their exceptional unitary conductance selective for K(+), joint activation mechanism by membrane depolarization and intracellular [Ca(2+)] elevation, and broad expression pattern. In this chapter, we discuss the structural basis and operational principles of their activation, or gating, by membrane potential and calcium. We also discuss how the two activation mechanisms interact to culminate in channel opening. As members of the voltage-gated potassium channel superfamily, BK channels are discussed in the context of archetypal family members, in terms of similarities that help us understand their function, but also seminal structural and biophysical differences that confer unique functional properties. PMID:27238260

  19. Central centrifugal cicatricial alopecia

    OpenAIRE

    Collin Blattner; Dennis C Polley; Frank Ferritto; Elston, Dirk M

    2013-01-01

    Central centrifugal cicatricial alopecia is a common cause of progressive permanent apical alopecia. This unique form of alopecia includes entities previously know as “hot comb alopecia,” “follicular degeneration syndrome,” “pseudopelade” in African Americans and “central elliptical pseudopelade” in Caucasians. The etiology appears to be multifactorial and the condition occurs in all races.

  20. Central pontine myelinolysis

    Science.gov (United States)

    ... from one nerve to another. The most common cause of central pontine myelinolysis is a quick change in the body's sodium ... The nerve damage caused by central pontine myelinolysis is usually ... The disorder can cause serious long-term (chronic) disability.

  1. Computer simulation of ion channel gating: the M(2) channel of influenza A virus in a lipid bilayer

    Science.gov (United States)

    Schweighofer, K. J.; Pohorille, A.

    2000-01-01

    The transmembrane fragment of the influenza virus M(2) protein forms a homotetrameric channel that transports protons. In this paper, we use molecular dynamics simulations to help elucidate the mechanism of channel gating by four histidines that occlude the channel lumen in the closed state. We test two competing hypotheses. In the "shuttle" mechanism, the delta nitrogen atom on the extracellular side of one histidine is protonated by the incoming proton, and, subsequently, the proton on the epsilon nitrogen atom is released on the opposite side. In the "water-wire" mechanism, the gate opens because of electrostatic repulsion between four simultaneously biprotonated histidines. This allows for proton transport along the water wire that penetrates the gate. For each system, composed of the channel embedded in a hydrated phospholipid bilayer, a 1.3-ns trajectory was obtained. It is found that the states involved in the shuttle mechanism, which contain either single-protonated histidines or a mixture of single-protonated histidines plus one biprotonated residue, are stable during the simulations. Furthermore, the orientations and dynamics of water molecules near the gate are conducive to proton transfer. In contrast, the fully biprotonated state is not stable. Additional simulations show that if only two histidines are biprotonated, the channel deforms but the gate remains closed. These results support the shuttle mechanism but not the gate-opening mechanism of proton gating in M(2).

  2. Cycling of grain legume residue nitrogen

    DEFF Research Database (Denmark)

    Jensen, E.S.

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... weeks of decomposition, due to high rates of residue N net mineralization and subsequent leaching and denitrification losses of N. Lysimeter experiments showed that pea residues may reduce leaching losses of N, probably due to their effect on the mineralization-immobilizalion turnover of N and...... denitrification. Winter barley succeeding field pea recovered 13% of the incorporated pea residue N by early December; the recovery was found to be 15% at maturity in July. A spring-sown crop of barley recovered less than half the amount of pea residue N recovered by winter barley. The residue N-use efficiencies...

  3. Resolution power of residual gas ionization monitors for proton beams at PETRA and HERA

    International Nuclear Information System (INIS)

    Residual gas ionisation monitors are used at DESY to measure emittances and profiles of proton beams. Multi channel plates are used as image itensifiers and video cameras are used to obsere the outcoming signals. The accuracy of this method is investigated. The influence of the space charge field of the proton bunches on the motion of ions within the monitors and instrumental effects on the obsered profile are surveyed. Theoretical calculations and Monte Carlo simulations are used to determine correction functions for these effects. The influence of the micro channel plates, optical systems and the video cameras on the obsered signals are also examined. (orig./HP)

  4. Central Diffraction at ALICE

    CERN Document Server

    Lämsä, Jerry W

    2011-01-01

    The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, hybrids and new charmonium-like states. It would also provide a good testing ground for detailed studies of heavy quarkonia. Due to its central barrel performance, ALICE can accurately measure the low-mass central systems with good purity. The efficiency of the Forward Multiplicity Detector (FMD) and the Forward Shower Counter (FSC) system for detecting rapidity gaps is shown to be adequate for the proposed studies. With this detector arrangement, valuable new data can be obtained by tagging central diffractive processes.

  5. Central diffraction at ALICE

    Energy Technology Data Exchange (ETDEWEB)

    Laemsae, J W; Orava, R, E-mail: risto.orava@helsinki.fi [Helsinki Insitute of Physics, and Division of Elementary Particle Physics, Department of Physics, PL 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki (Finland)

    2011-02-01

    The ALICE experiment is shown to be well suited for studies of exclusive final states from central diffractive reactions. The gluon-rich environment of the central system allows detailed QCD studies and searches for exotic meson states, such as glueballs, hybrids and new charmonium-like states. It would also provide a good testing ground for detailed studies of heavy quarkonia. Due to its central barrel performance, ALICE can accurately measure the low-mass central systems with good purity. The efficiency of the Forward Multiplicity Detector (FMD) and the Forward Shower Counter (FSC) system for detecting rapidity gaps is shown to be adequate for the proposed studies. With this detector arrangement, valuable new data can be obtained by tagging central diffractive processes.

  6. Residual number processing in dyscalculia

    Directory of Open Access Journals (Sweden)

    Marinella Cappelletti

    2014-01-01

    Full Text Available Developmental dyscalculia – a congenital learning disability in understanding numerical concepts – is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and categorical colour-decision tasks with numerical and non-numerical stimuli, with adults with dyscalculia performing slower than controls in the number semantic tasks only. Structural imaging showed less grey-matter volume in the right parietal cortex in people with dyscalculia relative to controls. Functional MRI showed that accurate number semantic judgements were maintained by parietal and inferior frontal activations that were common to adults with dyscalculia and controls, with higher activation for participants with dyscalculia than controls in the right superior frontal cortex and the left inferior frontal sulcus. Enhanced activation in these frontal areas was driven by people with dyscalculia who made faster rather than slower numerical decisions; however, activation could not be accounted for by response times per se, because it was greater for fast relative to slow dyscalculics but not greater for fast controls relative to slow dyscalculics. In conclusion, our results reveal two frontal brain regions that support efficient number processing in dyscalculia.

  7. Residual number processing in dyscalculia.

    Science.gov (United States)

    Cappelletti, Marinella; Price, Cathy J

    2014-01-01

    Developmental dyscalculia - a congenital learning disability in understanding numerical concepts - is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and categorical colour-decision tasks with numerical and non-numerical stimuli, with adults with dyscalculia performing slower than controls in the number semantic tasks only. Structural imaging showed less grey-matter volume in the right parietal cortex in people with dyscalculia relative to controls. Functional MRI showed that accurate number semantic judgements were maintained by parietal and inferior frontal activations that were common to adults with dyscalculia and controls, with higher activation for participants with dyscalculia than controls in the right superior frontal cortex and the left inferior frontal sulcus. Enhanced activation in these frontal areas was driven by people with dyscalculia who made faster rather than slower numerical decisions; however, activation could not be accounted for by response times per se, because it was greater for fast relative to slow dyscalculics but not greater for fast controls relative to slow dyscalculics. In conclusion, our results reveal two frontal brain regions that support efficient number processing in dyscalculia. PMID:24266008

  8. Residual Fragments after Percutaneous Nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Kaan Özdedeli

    2012-09-01

    Full Text Available Clinically insignificant residual fragments (CIRFs are described as asymptomatic, noninfectious and nonobstructive stone fragments (≤4 mm remaining in the urinary system after the last session of any intervention (ESWL, URS or PCNL for urinary stones. Their insignificance is questionable since CIRFs could eventually become significant, as their presence may result in recurrent stone growth and they may cause pain and infection due to urinary obstruction. They may become the source of persistent infections and a significant portion of the patients will have a stone-related event, requiring auxilliary interventions. CT seems to be the ultimate choice of assessment. Although there is no concensus about the timing, recent data suggests that it may be performed one month after the procedure. However, imaging can be done in the immediate postoperative period, if there are no tubes blurring the assessment. There is some evidence indicating that selective medical therapy may have an impact on decreasing stone formation rates. Retrograde intrarenal surgery, with its minimally invasive nature, seems to be the best way to deal with residual fragments.

  9. RESIDUAL STRESSES IN 3013 CONTAINERS

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Dunn, K.

    2009-11-10

    The DOE Complex is packaging plutonium-bearing materials for storage and eventual disposition or disposal. The materials are handled according to the DOE-STD-3013 which outlines general requirements for stabilization, packaging and long-term storage. The storage vessels for the plutonium-bearing materials are termed 3013 containers. Stress corrosion cracking has been identified as a potential container degradation mode and this work determined that the residual stresses in the containers are sufficient to support such cracking. Sections of the 3013 outer, inner, and convenience containers, in both the as-fabricated condition and the closure welded condition, were evaluated per ASTM standard G-36. The standard requires exposure to a boiling magnesium chloride solution, which is an aggressive testing solution. Tests in a less aggressive 40% calcium chloride solution were also conducted. These tests were used to reveal the relative stress corrosion cracking susceptibility of the as fabricated 3013 containers. Significant cracking was observed in all containers in areas near welds and transitions in the container diameter. Stress corrosion cracks developed in both the lid and the body of gas tungsten arc welded and laser closure welded containers. The development of stress corrosion cracks in the as-fabricated and in the closure welded container samples demonstrates that the residual stresses in the 3013 containers are sufficient to support stress corrosion cracking if the environmental conditions inside the containers do not preclude the cracking process.

  10. Mechanistic signs of double-barreled structure in a fluoride ion channel.

    Science.gov (United States)

    Last, Nicholas B; Kolmakova-Partensky, Ludmila; Shane, Tania; Miller, Christopher

    2016-01-01

    The Fluc family of F(-) ion channels protects prokaryotes and lower eukaryotes from the toxicity of environmental F(-). In bacteria, these channels are built as dual-topology dimers whereby the two subunits assemble in antiparallel transmembrane orientation. Recent crystal structures suggested that Fluc channels contain two separate ion-conduction pathways, each with two F(-) binding sites, but no functional correlates of this unusual architecture have been reported. Experiments here fill this gap by examining the consequences of mutating two conserved F(-)-coordinating phenylalanine residues. Substitution of each phenylalanine specifically extinguishes its associated F(-) binding site in crystal structures and concomitantly inhibits F(-) permeation. Functional analysis of concatemeric channels, which permit mutagenic manipulation of individual pores, show that each pore can be separately inactivated without blocking F(-) conduction through its symmetry-related twin. The results strongly support dual-pathway architecture of Fluc channels. PMID:27449280

  11. Computational Prediction of Heme-Binding Residues by Exploiting Residue Interaction Network

    OpenAIRE

    Rong Liu; Jianjun Hu

    2011-01-01

    Computational identification of heme-binding residues is beneficial for predicting and designing novel heme proteins. Here we proposed a novel method for heme-binding residue prediction by exploiting topological properties of these residues in the residue interaction networks derived from three-dimensional structures. Comprehensive analysis showed that key residues located in heme-binding regions are generally associated with the nodes with higher degree, closeness and betweenness, but lower ...

  12. Agricultural Residues Based Composites 1. Preparation of Fibrous Agricultural Residues

    International Nuclear Information System (INIS)

    The aim of this study is to use agricultural residues as bagasse, cotton stalks, rice straw, linen and linen fibers, which are produced in Egypt in huge amounts annually to produce composites with cement or gypsum. Also the effect of physical and chemical treatments of the fibers and the addition of some additives to the composites was studied. The mechanical properties of the produced composites also the effect of its firing at temperatures up to 800 degree C was tested after dipping in water for different time intervals (1-90 days). In this paper we considered only the preparation of different types of fibers, its grinding and separation to different fiber lengths (ca. 0.4 to 1.5 mm). The percent of each fiber length and its chemical and physical analysis is found

  13. Interfacial gating triad is crucial for electromechanical transduction in voltage-activated potassium channels

    Science.gov (United States)

    Chowdhury, Sandipan; Haehnel, Benjamin M.

    2014-01-01

    Voltage-dependent potassium channels play a crucial role in electrical excitability and cellular signaling by regulating potassium ion flux across membranes. Movement of charged residues in the voltage-sensing domain leads to a series of conformational changes that culminate in channel opening in response to changes in membrane potential. However, the molecular machinery that relays these conformational changes from voltage sensor to the pore is not well understood. Here we use generalized interaction-energy analysis (GIA) to estimate the strength of site-specific interactions between amino acid residues putatively involved in the electromechanical coupling of the voltage sensor and pore in the outwardly rectifying KV channel. We identified candidate interactors at the interface between the S4–S5 linker and the pore domain using a structure-guided graph theoretical approach that revealed clusters of conserved and closely packed residues. One such cluster, located at the intracellular intersubunit interface, comprises three residues (arginine 394, glutamate 395, and tyrosine 485) that interact with each other. The calculated interaction energies were 3–5 kcal, which is especially notable given that the net free-energy change during activation of the Shaker KV channel is ∼14 kcal. We find that this triad is delicately maintained by balance of interactions that are responsible for structural integrity of the intersubunit interface while maintaining sufficient flexibility at a critical gating hinge for optimal transmission of force to the pore gate. PMID:25311635

  14. Neuroprotective role of ATP-sensitive potassium channels in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Hong-shuo SUN; Zhong-ping FENG

    2013-01-01

    ATP-sensitive potassium (KATP) channels are weak,inward rectifiers that couple metabolic status to cell membrane electrical activity,thus modulating many cellular functions.An increase in the ADP/ATP ratio opens KATP channels,leading to membrane hyperpolarization.KATP channels are ubiquitously expressed in neurons located in different regions of the brain,including the hippocampus and cortex.Brief hypoxia triggers membrane hyperpolarization in these central neurons.In vivo animal studies confirmed that knocking out the Kir6.2 subunit of the KATP channels increases ischemic infarction,and overexpression of the Kir6.2 subunit reduces neuronal injury from ischemic insults.These findings provide the basis for a practical strategy whereby activation of endogenous KATP channels reduces cellular damage resulting from cerebral ischemic stroke.KATP channel modulators may prove to be clinically useful as part of a combination therapy for stroke management in the future.

  15. Graviton Signals in Central Production at the LHC

    CERN Document Server

    Basu, Rahul

    2013-01-01

    In this paper, we study central production, in the inclusive case, to look for graviton signals in large extra dimensional model using dilepton and diphoton channels. We carefully analyze signal and possible Standard Model background processes and study the feasibility of such new physics searches in a relatively clean environment as in central production where the proton fragments are mostly emitted in the forward direction, and there is a clear rapidity gap between them and the centrally produced system. Our analysis shows that the LHC with 14 TeV center of mass energy and 100 fb$^{-1}$ (300 fb$^{-1}$) of integrated luminosity can probe the effective gravity scale up to 3.6 TeV (4.4 TeV) in both the dilepton and diphoton channels.

  16. Thermo-Hydraulic behaviour of dual-channel superconducting Cable-In-Conduit Conductors for ITER

    International Nuclear Information System (INIS)

    In an effort to optimise the cryogenics of large superconducting coils for fusion applications (ITER), dual channel Cable-In-Conduit Conductors (CICC) are designed with a central channel spiral to provide low hydraulic resistance and faster helium circulation. The qualitative and economic rationale of the conductor central channel is here justified to limit the superconductor temperature increase, but brings more complexity to the conductor cooling characteristics. The pressure drop of spirals is experimentally evaluated in nitrogen and water and an explicit hydraulic friction model is proposed. Temperatures in the cable must be quantified to guarantee superconductor margin during coil operation under heat disturbance and set adequate inlet temperature. Analytical one-dimensional thermal models, in steady state and in transient, allow to better understand the thermal coupling of CICC central and annular channels. The measurement of a heat transfer characteristic space and time constants provides cross-checking experimental estimations of the internal thermal homogenization. A simple explicit model of global inter-channel heat exchange coefficient is proposed. The risk of thermosyphon between the two channels is considered since vertical portions of fusion coils are subject to gravity. The new hydraulic model, heat exchange model and gravitational risk ratio allow the thermohydraulic improvement of CICC central spirals. (author)

  17. Topography of the TH5 Segment in the Diphtheria Toxin T-Domain Channel.

    Science.gov (United States)

    Kienker, Paul K; Wu, Zhengyan; Finkelstein, Alan

    2016-04-01

    The translocation domain (T-domain) of diphtheria toxin contains 10 α helices in the aqueous crystal structure. Upon exposure to a planar lipid bilayer under acidic conditions, it inserts to form a channel and transport the attached amino-terminal catalytic domain across the membrane. The TH5, TH8, and TH9 helices form transmembrane segments in the open-channel state, with TH1-TH4 translocated across the membrane. The TH6-TH7 segment also inserts to form a constriction that occupies only a small portion of the total channel length. Here, we have examined the TH5 segment in more detail, using the substituted-cysteine accessibility method. We constructed a series of 23 mutant T-domains with single cysteine residues at positions in and near TH5, monitored their channel formation in planar lipid bilayers, and probed for an effect of thiol-specific reagents added to the solutions on either side of the membrane. For 15 of the mutants, the reagent caused a decrease in single-channel conductance, indicating that the introduced cysteine residue was exposed within the channel lumen. We also found that reaction caused large changes in ionic selectivity for some mutant channels. We determined whether reaction occurred in the open state or in the brief flicker-closed state of the channel. Finally, we compared the reaction rates from either side of the membrane. Our experiments are consistent with the hypotheses that the TH5 helix has a transmembrane orientation and remains helical in the open-channel state; they also indicate that the middle of the helix is aligned with the constriction in the channel. PMID:26645703

  18. Structure and Mechanism of a Pentameric Formate Channel

    Energy Technology Data Exchange (ETDEWEB)

    Waight, A.; Love, J; Wang, D

    2010-01-01

    Formate transport across the inner membrane is a critical step in anaerobic bacterial respiration. Members of the formate/nitrite transport protein family function to shuttle substrate across the cytoplasmic membrane. In bacterial pathogens, the nitrite transport protein is involved in protecting bacteria from peroxynitrite released by host macrophages. We have determined the 2.13-{angstrom} structure of the formate channel FocA from Vibrio cholerae, which reveals a pentamer in which each monomer possesses its own substrate translocation pore. Unexpectedly, the fold of the FocA monomer resembles that found in water and glycerol channels. The selectivity filter in FocA consists of a cytoplasmic slit and a central constriction ring. A 2.5-{angstrom} high-formate structure shows two formate ions bound to the cytoplasmic slit via both hydrogen bonding and van der Waals interactions, providing a structural basis for the substrate selectivity of the channel.

  19. PHYSICAL PROPERTIES OF CORN RESIDUES

    Directory of Open Access Journals (Sweden)

    Yaning Zhang

    2012-01-01

    Full Text Available Corn residues (cobs, leaves and stalks are abundantly available renewable materials that can be used as an energy source in gasification and combustion systems. Proper understanding of the physical properties of these materials is necessary for their use in thermochemical conversion processes. The physical properties (moisture content, particle size, bulk density and porosity of corn cobs, leaves and stalks were determined in this study. The moisture contents were 6.38, 7.92 and 6.40% of the cobs, leaves and stalks, respectively. The cobs had the highest weight percentage (18.23% of the small particles (0.850 mm. Most of the stalk particles (84.82% were in the range of 0.212-0.850 mm. The cob particle size had a normal concave (inward distribution between particle sizes 0.106 mm (18.23 weight % and 0.925 mm (25.26 weight % with the lowest weight percentage (5.30 weight % at 0.390 mm particle size while the stalk particle size had a normal convex (outward distribution between particle sizes 0.106 mm (8.49 weight % and 0.925 mm (6.69 weight % with the highest weight percentage (23.47 weight % at the 0.605 mm particle size. The leaves had an increasing trend of particle size distribution between the particle sizes 0.106 and 0.925 mm. The average particle sizes for the cobs, leaves and stalks were 0.56, 0.70 and 0.49 mm, respectively. The average bulk density was 282.38, 81.61 and 127.32 kg m-3 for the corn cobs, leaves and stalks, respectively. The average porosity was 67.93, 86.06 and 58.51% for the corn cobs, leaves and stalks, respectively. A positive relationship between the average particle size and the porosity was observed for the corn residues. The differences in the physical properties among the corn residues (cobs, leaves and stalks observed in this study are due to variations in the compositions and structures of these materials.

  20. State-Dependent Inhibition of Sodium Channels by Local Anesthetics: A 40-Year Evolution.

    Science.gov (United States)

    Wang, G-K; Strichartz, G R

    2012-04-01

    Knowledge about the mechanism of impulse blockade by local anesthetics has evolved over the past four decades, from the realization that Na(+) channels were inhibited to affect the impulse blockade to an identification of the amino acid residues within the Na(+) channel that bind the local anesthetic molecule. Within this period appreciation has grown of the state-dependent nature of channel inhibition, with rapid binding and unbinding at relatively high affinity to the open state, and weaker binding to the closed resting state. Slow binding of high affinity for the inactivated state accounts for the salutary therapeutic as well as the toxic actions of diverse class I anti-arrhythmic agents, but may have little importance for impulse blockade, which requires concentrations high enough to block the resting state. At the molecular level, residues on the S6 transmembrane segments in three of the homologous domains of the channel appear to contribute to the binding of local anesthetics, with some contribution also from parts of the selectivity filter. Binding to the inactivated state, and perhaps the open state, involves some residues that are not identical to those that bind these drugs in the resting state, suggesting spatial flexibility in the "binding site". Questions remaining include the mechanism that links local anesthetic binding with the inhibition of gating charge movements, and the molecular nature of the theoretical "hydrophobic pathway" that may be critical for determining the recovery rates from blockade of closed channels, and thus account for both therapeutic and cardiotoxic actions. PMID:23710324

  1. Channel's Concurrence and Quantum Teleportation

    Institute of Scientific and Technical Information of China (English)

    LING Yin-Sheng

    2005-01-01

    Concurrence can measure the entanglement property of a system. If the channel is a pure state, positive concurrence state can afford the good performance in the teleportation process. If the channel ia a mixed state, positive concurrence state cannot assure the good performance in the teleportation. The conditions of the positive concurrence and the quantum teleportation in the Heisenberg spin ring is derived.

  2. Channel's Concurrence and Quantum Teleportation

    International Nuclear Information System (INIS)

    Concurrence can measure the entanglement property of a system. If the channel is a pure state, positive concurrence state can afford the good performance in the teleportation process. If the channel ia a mixed state, positive concurrence state cannot assure the good performance in the teleportation. The conditions of the positive concurrence and the quantum teleportation in the Heisenberg spin ring is derived.

  3. Defect Distributions in Channeling Experiments

    DEFF Research Database (Denmark)

    Andersen, Hans Henrik; Sigmund, P.

    radiation damage by channeled particles. As an application, one gets a necessary criterion for the occurence of super tails in channeling experiments. The theory involves some assumptions on the behaviour of Born-Mayer potentials which are verified by comparison to experimental displacement energies....

  4. Hydraulic jumps in a channel

    DEFF Research Database (Denmark)

    Bonn, D.; Andersen, Anders Peter; Bohr, Tomas

    2009-01-01

    We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected...

  5. Synchronization strategies for RFI channels

    Science.gov (United States)

    Mceliece, R. J.; Vantilborg, H.; Tung, S.

    1977-01-01

    An RFI channel to be a multiple-access channel is defined in which no sender can know when any other starts, and the problem of determining the relative phases of the senders at the receiver is studied. A new result is proved about binary DEBruijn sequences.

  6. An improved channel assessment scheme

    KAUST Repository

    Bader, Ahmed

    2014-05-01

    A source node in a multihop network determines whether to transmit in a channel based on whether the channel is occupied by a packet transmission with a large number of relays; whether the source node is in the data tones back-off zone; and the source node is in the busy tone back-off zone.

  7. Shellfish Toxins Targeting Voltage-Gated Sodium Channels

    OpenAIRE

    Fan Zhang; Xunxun Xu; Tingting Li; Zhonghua Liu

    2013-01-01

    Voltage-gated sodium channels (VGSCs) play a central role in the generation and propagation of action potentials in excitable neurons and other cells and are targeted by commonly used local anesthetics, antiarrhythmics, and anticonvulsants. They are also common targets of neurotoxins including shellfish toxins. Shellfish toxins are a variety of toxic secondary metabolites produced by prokaryotic cyanobacteria and eukaryotic dinoflagellates in both marine and fresh water systems, which can acc...

  8. Global Banking and the Balance Sheet Channel of Monetary Transmission

    OpenAIRE

    Uluc Aysun; Sami Alpanda

    2012-01-01

    The literature typically finds that the development of financial markets has decreased the ability of central banks to affect the real economy. This paper shows that this negative relationship does not hold between the balance sheet channel of monetary transmission and bank globalization -- one aspect of financial development. The reason is that global banks are more sensitive to their borrowers’ leverage. By affecting this leverage, monetary policy has a larger impact on global banks’ lendin...

  9. Radioactive inputs to the North Sea and the Channel

    International Nuclear Information System (INIS)

    The subject is covered in sections: introduction (radioactivity; radioisotopes; discharges from nuclear establishments); data sources (statutory requirements); sources of liquid radioactive waste (figure showing location of principal sources of radioactive discharges; tables listing principal discharges by activity and by nature of radioisotope); Central Electricity Generating Board nuclear power stations; research and industrial establishments; Ministy of Defence establishments; other UK inputs of radioactive waste; total inputs to the North Sea and the Channel (direct inputs; river inputs; adjacent sea areas); conclusions. (U.K.)

  10. Transfer information remotely via noise entangled coherent channels

    CERN Document Server

    Allati, A El; Hassouni, Y

    2010-01-01

    In this contribution, a generalized protocol of quantum teleportation is suggested to investigate the possibility of remotely transfer unknown multiparities entangled coherent state. A theoretical technique is introduced to generate maximum entangled coherent states which are used as quantum channels. We show that the mean photon number plays a central role on the fidelity of the transferred information. The noise parameter can be considered as a control parameter only for small values of the mean photon number.

  11. Effect of Residue Mutation on the Electrostatic Potential in EcCIC

    Institute of Scientific and Technical Information of China (English)

    ZOU Xianwu; DONG Shuxiang; WANG Xiaoqing; HUANG Shengyou

    2007-01-01

    The effect of mutation of strongly conserved porelining residues in the chloride channel EcClC on the electrostatic potential and binding free energy of the chloride ion was studied using explicit protein-membrane structures. Electrostatic potential distribution and binding free energy of the chloride ion at different binding sites in the wild-type and mutated EcClC were calculated with APBS. The potential data reveal that the electrostatic potential around the selectivity filter, especially around the site Sext and Scen becomes more negative as the residue R147 was mutated to C147. The electrostatic binding free energy shows that the binding free energy of the chloride ion at all binding sites becomes more positive as R147 was mutated. It follows that mutation of R147 decreases ion stabilization at binding sites and affects channel's gating.

  12. Residual Liquefaction under Standing Waves

    DEFF Research Database (Denmark)

    Kirca, V.S. Ozgur; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    This paper summarizes the results of an experimental study which deals with the residual liquefaction of seabed under standing waves. It is shown that the seabed liquefaction under standing waves, although qualitatively similar, exhibits features different from that caused by progressive waves....... The experimental results show that the buildup of pore-water pressure and the resulting liquefaction first starts at the nodal section and spreads towards the antinodal section. The number of waves to cause liquefaction at the nodal section appears to be equal to that experienced in progressive waves for the same...... wave height. Recommendations are made as to how to assess liquefaction potential in standing waves. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE)....

  13. Upgraded wood residue fuels 1995

    International Nuclear Information System (INIS)

    The Swedish market for upgraded residue fuels, i.e. briquettes, pellets and wood powder, has developed considerably during the nineties. The additional costs for the upgrading processes are regained and create a surplus in other parts of the system, e.g. in the form of higher combustion efficiencies, lower investment costs for burning equipment, lower operation costs and a diminished environmental impact. All these factors put together have resulted in a rapid growth of this part of the energy sector. In 1994 the production was 1.9 TWh, an increase of 37 % compared to the previous year. In the forthcoming heating season 1995/96 the production may reach 4 TWh. 57 refs, 11 figs, 6 tabs

  14. Forest residues in cattle feed

    Directory of Open Access Journals (Sweden)

    João Elzeário Castelo Branco Iapichini

    2012-12-01

    Full Text Available The ruminants are capable of converting low-quality food, when they are complementes with high-energy source. Through the use of regional agricultural residues is possible to conduct more economical production systems, since energetic foods have high cost in animal production. There is very abundant availability of residues in agroforestry activities worldwide, so that if a small fraction of them were used with appropriate technical criteria they could largely meet the needs of existing herds in the world and thus meet the demands of consumption of protein of animal origin. The Southwest Region of São Paulo State has large area occupied by reforestation and wide availability of non-timber forest residues, which may represent more concentrated energetic food for ruminant production. This experiment aimed to evaluate the acceptability of ground pine (20, 30 and 40%, replacing part of the energetic food (corn, present in the composition of the concentrate and was performed at the Experimental Station of Itapetininga - Forest Institute / SMA, in the dry season of 2011. It were used four crossbred steers, mean 18 months old, average body weight of 250 kg, housed in a paddock provided with water ad libitum and covered troughs for supplementation with the experimental diet. The adjustment period of the animals was of 07 days and the measurement of the levels of consumption, physiological changes, acceptability and physiological parameters were observed during the following 25 days. The concentrate supplement was formulated based on corn (76.2%, Soybean Meal (20%, urea (2%, Ammonium sulfate (0.4%, calcite (1.4%, Mineral Core (1% and finely ground Pine Cone, replacing corn. In preparing food, the formulas were prepared to make them isoproteic/energetic, containing the following nutrient levels: 22% Crude Protein (CP and 79% of Total Nutrients (TDN. The animals received the supplement in three steps for each level of cone replaced, being offered in the

  15. 75 FR 74697 - Central Oregon Irrigation District; Notice of Competing Preliminary Permit Application Accepted...

    Science.gov (United States)

    2010-12-01

    ... Energy Regulatory Commission Central Oregon Irrigation District; Notice of Competing Preliminary Permit..., 2010, Central Oregon Irrigation District filed an application for a preliminary permit, pursuant to... diversion control; (4) a 400-foot-long lined canal and flume channel; (5) a 45-foot-long,...

  16. Discrete-state model of coupled ion permeation and fast gating in ClC chloride channels

    International Nuclear Information System (INIS)

    A simple discrete-state model of ion permeation through a channel protein is considered in which the flow of ions through the open channel is coupled to the opening/closing of a gate by virtue of configurational changes in a particular pore-lining amino acid residue. The model is designed so as to represent essential features of ClC chloride channels, in which a particular glutamate residue (E148 in bacterial ClC channels) is thought to switch from a conformation that is pinned back (away from the pore itself) to one where this side group blocks the channel at a Cl- binding site. Thus, competition between the gate residue and Cl- ions for this site leads to interesting kinetics, such as the saturation of the gate closing time with increasing concentration of internal Cl- concentration. Analysis of the model proposed here shows that it can account for many qualitative features of ion channel permeation and gate closing rates in ClC-type channels observed experimentally and in recent computer simulations of these processes

  17. Labelled compounds for agrochemical residue studies in developing countries

    International Nuclear Information System (INIS)

    Potential applications of stable and radioactive isotopic tracers for assessing undesirable contaminants in agriculture, fisheries and food are discussed as related to developing countries. Sources and types of residues are considered, and their local implications; also, the availability of suitably labelled compounds, including possible international cooperation to facilitate more centralized and economic preparation, and the distribution of labelled intermediates and compounds for use by local scientists. The provision of training courses and their syllabus are reviewed. Experience in the Joint FAO/IAEA chemical residue and pollution programme has indicated a need for longer-lived radioisotopically labelled pesticides (insecticides, acaricides, fungicides, herbicides, fumigants, etc.) for studying their behaviour. 15N-, 13C- or 2H-labelled fertilizers and fertilizer additives such as nitrification inhibitors will shortly be needed, for studying the behaviour of fertilizer nitrogen residues, and their regulation and conservation, under conditions prevailing in the developing countries. Compounds labelled with stable isotopes are considered particularly valuable under field conditions. The report reviews the present situation and presents specific recommendations to the Directors General of FAO and IAEA

  18. Canonical framework for multi-channel SAR-GMTI

    Institute of Scientific and Technical Information of China (English)

    Liu Congfeng; Liao Guisheng

    2008-01-01

    Synthetic aperture radar (SAR) systems have become an important tool for fine-resolution mapping and other remote sensing operations.The multi-channel SAR ground moving-target indication (GMTI) must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets.The topic of moving-target detection in clutter has been extensively studied,and there are many methods that are used to detect moving targets,such as displaced phase center antenna (DPCA) method,along-track interfero-metric (ATI) phase,space-time adaptive processing (STAP),or some other metrics.A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods,namely,DPCA and ATI.The statistical test metric for multi-channel SAR-GMTI is established in a simple form,via the definition of the complex central Wishart distribution,to deduce the statistics of the test metric,and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case,namely the x2 distribution.The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector,and derives the constant false alarm rate (CFAR) detector tests for separating moving targets from clutter.

  19. Tidal Residual Eddies and their Effect on Water Exchange in Puget Sound

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Wang, Taiping

    2013-08-30

    Tidal residual eddies are one of the important hydrodynamic features in tidally dominant estuaries and coastal bays, and they could have significant effects on water exchange in a tidal system. This paper presents a modeling study of tides and tidal residual eddies in Puget Sound, a tidally dominant fjord-like estuary in the Pacific Northwest coast, using a three-dimensional finite-volume coastal ocean model. Mechanisms of vorticity generation and asymmetric distribution patterns around an island/headland were analyzed using the dynamic vorticity transfer approach and numerical experiments. Model results of Puget Sound show that a number of large twin tidal residual eddies exist in the Admiralty Inlet because of the presence of major headlands in the inlet. Simulated residual vorticities near the major headlands indicate that the clockwise tidal residual eddy (negative vorticity) is generally stronger than the anticlockwise eddy (positive vorticity) because of the effect of Coriolis force. The effect of tidal residual eddies on water exchange in Puget Sound and its sub-basins were evaluated by simulations of dye transport. It was found that the strong transverse variability of residual currents in the Admiralty Inlet results in a dominant seaward transport along the eastern shore and a dominant landward transport along the western shore of the Inlet. A similar transport pattern in Hood Canal is caused by the presence of tidal residual eddies near the entrance of the canal. Model results show that tidal residual currents in Whidbey Basin are small in comparison to other sub-basins. A large clockwise residual circulation is formed around Vashon Island near entrance of South Sound, which can potentially constrain the water exchange between the Central Basin and South Sound.

  20. Tidal residual eddies and their effect on water exchange in Puget Sound

    Science.gov (United States)

    Yang, Zhaoqing; Wang, Taiping

    2013-08-01

    Tidal residual eddies are one of the important hydrodynamic features in tidally dominant estuaries and coastal bays, and they could have significant effects on water exchange in a tidal system. This paper presents a modeling study of tides and tidal residual eddies in Puget Sound, a tidally dominant fjord-like estuary in the Pacific Northwest coast, using a three-dimensional finite-volume coastal ocean model. Mechanisms of vorticity generation and asymmetric distribution patterns around an island/headland were analyzed using the dynamic vorticity transfer approach and numerical experiments. Model results of Puget Sound show that a number of large twin tidal residual eddies exist in the Admiralty Inlet because of the presence of major headlands in the inlet. Simulated residual vorticities near the major headlands indicate that the clockwise tidal residual eddy (negative vorticity) is generally stronger than the anticlockwise eddy (positive vorticity) because of the effect of Coriolis force. The effect of tidal residual eddies on water exchange in Puget Sound and its subbasins was evaluated by simulations of dye transport. It was found that the strong transverse variability of residual currents in the Admiralty Inlet results in a dominant seaward transport along the eastern shore and a dominant landward transport along the western shore of the inlet. A similar transport pattern in Hood Canal is caused by the presence of tidal residual eddies near the entrance of the canal. Model results show that tidal residual currents in Whidbey Basin are small in comparison to other subbasins. A large clockwise residual circulation is formed around Vashon Island near entrance of South Sound, which can potentially constrain the water exchange between the Central Basin and South Sound.

  1. Adaptive MMSE Equalizer for Blind Fractional Spaced CMA Channel Equalization through LMS Algorithm

    Directory of Open Access Journals (Sweden)

    Tara.Saikumar

    2012-02-01

    Full Text Available The adaptive algorithm has been widely used in the digital signal processing like channel estimation, channel equalization, echo cancellation, and so on. One of the most important adaptive algorithms is the LMS algorithm. We present in this paper an multiple objective optimization approach to fast blind channel equalization. By investigating first the performance (mean-square error of the standard fractionally spaced CMA (constant modulus algorithm equalizer in the presence of noise, we show that CMA local minima exist near the minimum mean-square error (MMSE equalizers. Consequently, Fractional Spaced CMA may converge to a local minimum corresponding to a poorly designed MMSE receiver with considerable large mean-square error. The step size in the LMS algorithm decides both the convergence speed and the residual error level, the highest speed of convergence and residual error level.

  2. Quantum systems, channels, information. A mathematical introduction

    Energy Technology Data Exchange (ETDEWEB)

    Holevo, Alexander S.

    2012-07-01

    The subject of this book is theory of quantum system presented from information science perspective. The central role is played by the concept of quantum channel and its entropic and information characteristics. Quantum information theory gives a key to understanding elusive phenomena of quantum world and provides a background for development of experimental techniques that enable measuring and manipulation of individual quantum systems. This is important for the new efficient applications such as quantum computing, communication and cryptography. Research in the field of quantum informatics, including quantum information theory, is in progress in leading scientific centers throughout the world. This book gives an accessible, albeit mathematically rigorous and self-contained introduction to quantum information theory, starting from primary structures and leading to fundamental results and to exiting open problems.

  3. Opening Channels of Communication

    Directory of Open Access Journals (Sweden)

    Clarice Moura Costa

    2009-03-01

    Full Text Available Psychosis, as described through a psychodynamic perspective, is conceptualized as an attempt to deny the enveloping reality to avoid contact with the other. Music therapy is a way to break this barrier of non-communication raised by the patients. The music therapy process is configured as a trinomial – action (making music/ relationship (action with the other/communication (musical or verbal voluntary expression of feelings and conflicts, which, although intrinsically connected, is perceived in a sequential process. Aulagnier asserts that psychic activity represents the conjunction of three modes of functioning: the original process, the primary process and the secondary process. The perception of sound passes through three phases, corresponding to each manner of functioning of the psychic system – the pleasure of hearing, the desire to listen (to the other and the imperative of meaning. The music therapy process offers a significant similarity with the theory proposed by Aulagnier. We propose the hypothesis that in music therapy, there is an opportunity to (reexperience very archaic phases in the constitution of the ego, but in a new manner, so helping to open communication channels. This theoretical hypothesis is illustrated by real examples of patients.

  4. K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration

    OpenAIRE

    Kuiper, Els F. E.; Nelemans, Ad; Luiten, Paul; Nijholt, Ingrid; Dolga, Amalia; Eisel, Uli

    2012-01-01

    Calcium-activated potassium (K(Ca)) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of K(Ca) channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates action potential firing and limits the firing frequency of repetitive action potentials. Different subtypes of K(Ca) channels were anticipated on the basis of their physiological and pharmacological pro...

  5. K(Ca)2 and k(ca)3 channels in learning and memory processes, and neurodegeneration

    NARCIS (Netherlands)

    Kuiper, Els F.E.; Nelemans, Ad; Luiten, Paul; Nijholt, Ingrid; Dolga, Amalia; Eisel, Uli

    2012-01-01

    Calcium-activated potassium (K(Ca)) channels are present throughout the central nervous system as well as many peripheral tissues. Activation of K(Ca) channels contribute to maintenance of the neuronal membrane potential and was shown to underlie the afterhyperpolarization (AHP) that regulates actio

  6. THE DISTRIBUTION FUNCTION OF RESIDUE-RESIDUE CONTACTS IN PROTEIN MOLECULES

    Institute of Scientific and Technical Information of China (English)

    Xiang-hong Wang; Jian-hong Ke; Zhen-quan Lin

    2005-01-01

    In protein molecules each residue has a different ability to form contacts. In this paper, we calculated the number of contacts per residue and investigated the distribution of residue-residue contacts from 495 globular protein molecules using Contacts of Structural Units (CSU) software. It was found that the probability P(n) of amino acid residues having n pairs of contacts in all contacts fits Gaussian distribution very well. The distribution function of residue-residue contacts can be expressed as: P(n) = P0 + aexp[-b(n - nc)2]. In our calculation, P0 = -0.06, a = 11.4, b = -0.04 and nc = 9.0. According to distribution function, we found that those hydrophobic (H) residues including Leu, Val, Ile, Met, Phe, Tyr, Cys, and Trp residues have large values of the most probable number of contact nc, and hydrophilic (P) residues including Ala, Gly, Thr,His, Glu, Gln, Asp, Asn, Lys, Ser, Arg, and Pro residues have the small ones. We also compare with Fauchere-Pliska hydrophobicity scale (FPH) and the most probable number of contact nc for 20 amino acid residues, and find that there exists a linear relationship between Fauchere-Pliska hydrophobicity scale (FPH) and the most probable number of contact nc,and it is expressed as: nc = a + b × FPH, here a = 8.87, and b = 1.15. It is important to further explain protein folding and its stability from residue-residue contacts.

  7. Visualization by the Method of Color Shadow Imaging Using the Residual Chromatism of an Optical System

    Science.gov (United States)

    Chaplits*, A. D.

    2014-05-01

    Results of the visualization of the gas flow in the inner channel of an apparatus for reducing the sound of a shot using the residual chromatism of a Toepler lens device with an adjustable location of the light source are presented. Color shadow images were obtained without introduction of additional prisms, light filters, or diaphragms into the lighting part of this device. The images obtained made it possible to determine the features of the indicated flow.

  8. Residual strain in the Nb-H system measured by selected area diffraction (SAD)

    International Nuclear Information System (INIS)

    Various specimens of Nb were annealed in vacuum of 10-3 torr for four hours at 17700K. These speciments were doped with hydrogen up to 1000 ppm by weight and then were analyzed selected area diffraction. The line resolution of the electron channelling pattern was meassured for the specimens with different hydrogen content. These measurements, combined with the measurement of density, permitted one to estimate the residual strain caused by hydrogen. (Author)

  9. A secure and private RFID authentication protocol based on quadratic residue

    OpenAIRE

    Kardaş, Süleyman; Kardas, Suleyman; ÇELIK, Serkan; CELIK, SERKAN; Sarıyüce, Mehmet; Sariyuce, Mehmet; Levi, Albert

    2012-01-01

    Radio Frequency IDentification based systems are getting pervasively deployed in many real-life applications in various settings for identification and authentication of remote objects. However, the messages that are transmitted over a insecure channel, are vulnerable to security and privacy concerns such as data privacy, location privacy of tag owner and etc. Recently, Yeh et al.'s proposed a RFID authentication protocol based on quadratic residue which is claimed to provide location privacy...

  10. Single-Channel Recording of Ligand-Gated Ion Channels.

    Science.gov (United States)

    Plested, Andrew J R

    2016-01-01

    Single-channel recordings reveal the microscopic properties of individual ligand-gated ion channels. Such recordings contain much more information than measurements of ensemble behavior and can yield structural and functional information about the receptors that participate in fast synaptic transmission in the brain. With a little care, a standard patch-clamp electrophysiology setup can be adapted for single-channel recording in a matter of hours. Thenceforth, it is a realistic aim to record single-molecule activity with microsecond resolution from arbitrary cell types, including cell lines and neurons. PMID:27480725

  11. M channel enhancers and physiological M channel block.

    Science.gov (United States)

    Linley, John E; Pettinger, Louisa; Huang, Dongyang; Gamper, Nikita

    2012-02-15

    M-type (Kv7, KCNQ) K(+) channels control the resting membrane potential of many neurons, including peripheral nociceptive sensory neurons. Several M channel enhancers were suggested as prospective analgesics, and targeting M channels specifically in peripheral nociceptors is a plausible strategy for peripheral analgesia. However, receptor-induced inhibition of M channels in nociceptors is often observed in inflammation and may contribute to inflammatory pain. Such inhibition is predominantly mediated by phospholipase C. We investigated four M channel enhancers (retigabine, flupirtine, zinc pyrithione and H(2)O(2)) for their ability to overcome M channel inhibition via two phospholipase C-mediated mechanisms, namely depletion of membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) and a rise in intracellular Ca(2+) (an action mediated by calmodulin). Data from overexpressed Kv7.2/Kv7.3 heteromers and native M currents in dorsal root ganglion neurons suggest the following conclusions. (i) All enhancers had a dual effect on M channel activity, a negative shift in voltage dependence and an increase of the maximal current at saturating voltages. The enhancers differed in their efficacy to produce these effects. (ii) Both PIP(2) depletion and Ca(2+)/calmodulin strongly reduced the M current amplitude; however, at voltages near the threshold for M channel activation (-60 mV) all enhancers were able to restore M channel activity to a control level or above, while at saturating voltages the effects were more variable. (iii) Receptor-mediated inhibition of M current in nociceptive dorsal root ganglion neurons did not reduce the efficacy of retigabine or flupirtine to hyperpolarize the resting membrane potential. In conclusion, we show that all four M channel enhancers tested could overcome both PIP(2) and Ca(2+)-calmodulin-induced inhibition of Kv7.2/7.3 at voltages close to the threshold for action potential firing (-60 mV) but generally had reduced efficacy at a

  12. Central line infections - hospitals

    Science.gov (United States)

    ... risk is higher if you: Are in the intensive care unit (ICU) Have a weakened immune system or serious ... unless you have washed your hands. Tell your nurse if your central line: Gets dirty Is coming ...

  13. Central Data Exchange

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Central Data Exchange (CDX) enables fast, efficient and more accurate environmental data submissions from state and local governments, industry and tribes to...

  14. "Central Station" Londonis

    Index Scriptorium Estoniae

    2000-01-01

    Londoni galeriis Milch seitsme läti, leedu ja eesti kunstniku projekt "Central Station". Kuraatorid Lisa Panting, Sally Tallant. Eestist osalevad Hanno Soans (Catarina Campinoga koostöös valminud video), Kiwa, Kai Kaljo

  15. Central Asian Republic Info

    Data.gov (United States)

    US Agency for International Development — CAR Info is designed and managed by the Central Asian Republic Mission to fill in the knowledge and reporting gaps in existing agency systems for that Mission. It...

  16. Central nervous system

    Science.gov (United States)

    The central nervous system is composed of the brain and spinal cord. Your brain and spinal cord serve as the main "processing center" for your entire nervous system. They control all the workings of your body.

  17. Central nervous system resuscitation

    DEFF Research Database (Denmark)

    McIntosh, T K; Garde, E; Saatman, K E;

    1997-01-01

    Traumatic injury to the central nervous system induces delayed neuronal death, which may be mediated by acute and chronic neurochemical changes. Experimental identification of these injury mechanisms and elucidation of the neurochemical cascade following trauma may provide enhanced opportunities...

  18. RESIDUES IN CARROTS TREATED WITH LINURON

    DEFF Research Database (Denmark)

    Løkke, Hans

    1974-01-01

    Investigations have been carried out on residues of linuron and its breakdown products in carrots sprayed with Jinuron at 1, 2, or 4 kg a.i./ha, 0, 19, 28, 36 or 60 days after sowing (up to 57 days before harvesting). The extracted residues were separated into three fractions by liquid-liquid par......Investigations have been carried out on residues of linuron and its breakdown products in carrots sprayed with Jinuron at 1, 2, or 4 kg a.i./ha, 0, 19, 28, 36 or 60 days after sowing (up to 57 days before harvesting). The extracted residues were separated into three fractions by liquid......,4-dichloroaniline and iodide ion, followed by gas chromatography with electron capture detector. Only 5-13% of the extract-able residues were breakdown products. Most of the detectable residue (87-95%) was identified as linuron. The relative proportions of linuron and breakdown products in carrots at the time...

  19. Decreasing residual aluminum level in drinking water

    Institute of Scientific and Technical Information of China (English)

    王志红; 崔福义

    2004-01-01

    The relativity of coagulant dosage, residual turbidity, temperature, pH etc. with residual aluminum concentration were investigated, and several important conclusions were achieved. Firstly, dosage of alum-coagulant or PAC1 influences residual aluminum concentration greatly. There is an optimal-dosage-to-aluminum, a bit less than the optimal-dosage-to-turbidity. Secondly, it proposes that decreasing residual aluminum concentration can be theoretically divided into two methods, either decreasing (even removing) the concentration of particulate aluminum component, or decreasing dissolved aluminum. In these tests there is an optimal value of residual turbidity of postprecipitation at 7.0 NTU. Thirdly, residual aluminum level will increase while water temperature goes higher. At the last, optimal pH value corresponds a minimum dissolved aluminum at a given turbidity. Data shows the optimal pH value decreases with water temperature's increasing.

  20. Residual analysis for spatial point processes

    DEFF Research Database (Denmark)

    Baddeley, A.; Turner, R.; Møller, Jesper;

    2005-01-01

    We define residuals for point process models fitted to spatial point pattern data, and we propose diagnostic plots based on them. The residuals apply to any point process model that has a conditional intensity; the model may exhibit spatial heterogeneity, interpoint interaction and dependence on...... spatial covariates. Some existing ad hoc methods for model checking (quadrat counts, scan statistic, kernel smoothed intensity and Berman's diagnostic) are recovered as special cases. Diagnostic tools are developed systematically, by using an analogy between our spatial residuals and the ususal residuals...... plots. A plot of smoothed residuals against spatial location, or against a spatial covariate, is effective in diagnosing spatial trend or covariate effects. Q-Q plots of the residuals are effective in diagnosing interpoint interaction....