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Sample records for chloride channel closing

  1. 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.

  2. The H-loop in the Second Nucleotide-binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator is Required for Efficient Chloride Channel Closing

    OpenAIRE

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine res...

  3. Regulated trafficking of the CFTR chloride channel

    NARCIS (Netherlands)

    Braakman, L.J.; Kleizen, B.; Jonge, H.R. de

    2000-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR), the ABC transporter encoded by the cystic fibrosis gene, is localized in the apical membrane of epithelial cells where it functions as a cyclic AMP-regulated chloride channel and as a regulator of other ion channels and transporters. Wh

  4. Effects of antigliomatin from the scorpion venom of Buthus martensii Karsch on chloride channels on C6 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Zan Wang; Mingxian Li; Hongmei Meng; Min Huang; Weihong Lin; Li Cui; Shao Wang

    2011-01-01

    Using whole-cell patch-clamp recordings, the effects of antigliomatin were observed on chloride channels on C6 glioma cells cultured in vitro. Antigliomatin was extracted from the venom of the scorpion Buthus martensii Karsch. Chloride channels are closed under normal osmotic pressure. When osmotic pressure was reduced to 120, 110 and 100 mV, the cell volume enlarged, chloride channels opened, and the chloride channel current increased. Three minutes after antigliomatin treatment, the chloride channel current decreased in a dose-dependent manner. These results show that antigliomatin extracted from the venom of the scorpion Buthus martensii Karsch diminishes chloride channel currents on C6 glioma cells.

  5. Chloride channels in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1982-01-01

    A study of the voltage and time dependence of a transepithelial Cl- current in toad skin (Bufo bufo) by the voltage-clamp method leads to the conclusion that potential has a dual role for Cl- transport. One is to control the permeability of an apical membrane Cl-pathway, the other is to drive Cl-...... that Cl- transport through open channels does not obey the constant-field equation....

  6. Chloride channels and the reactions of cells to topography

    Directory of Open Access Journals (Sweden)

    Tobasnick G.

    2001-12-01

    Full Text Available The reactions of rat epitenon cells to substratum topography on the micrometric and nanometric scale such as groove-ridge structures include cell extension, elongation and orientation reactions. In this paper we report that stretch-sensitive chloride channels may be involved in the earliest stages of these reactions in epitenon fibroblast-like cells. We report that rat epitenon-cells can develop appreciable lateral mechanical tension that could stretch both the force generating cells themselves and those nearby. We show that cells in medium in which more than 80% of the chloride has been replaced by nitrate show little reaction to topography. Spreading of the cells takes place but is much reduced along the direction of the groove-ridge topography but enhanced across the topography. The chloride channel inhibitors NPPB (5-Nitro-2- (3phenylpropylamino benzoicacid 4,4'-disothiocyanostilbene-2, 2' sulphonic acid (DIDS and Chlorotoxin produce similar results which are further accentuated when these inhibitors are presented in low chloride medium. An antibody against ClC3, which has close homology to ClC5/6 also, blocked reaction to topography. These treatments have no significant effect on cell spreading on planar surfaces nor do they lead to changes in internal pH in the cells. There is a slight inhibition of rates of cell movement . Experiments using antisense oligoribonucleotides to ClC-5 or ClC-6 channel m-RNA also inhibit topographic reactions, which provides further confirmation of the hypothesis. Since the ClC-3,4 and 5 share considerable sequence similarities in the genes and in their proteins it has not been possible to make an unambigous determination of which precise chloride channel(s is (are involved.

  7. Chloride Channel Myotonia: Study of Five Cases

    Directory of Open Access Journals (Sweden)

    M Ghofrani

    2002-09-01

    Full Text Available Chloride channel Myotonia is a form of channelopathy, and Myotonia is its manifestation. Myotonia may be defined as delayed relaxation of skeletal muscle after its contraction. Decreased chloride conductance across the transverse tubular system, renders the muscle membrane hyper-excitable and leads to repetitive firing, creating Myotonia. Myotonia congenital is another name for chloride channel Myotonia. Myotonia congenital appears in autosomal dominant type called Thomson disease, autosomal recessive type called Becker disease, and a type with sporadic occurrence. Symptoms appear in the first or second decade of life. Repeated muscle contraction, the so called warm up, result in resolution of the Myotonia stiffness. Muscle stiffness and hypertrophy is another finding at physical examination. In this study we report on 5 patients, which had clinical and electrical signs of Myotonia. Muscle hypertrophy and warm up phenomena were present in all cases. CPK measurement of all cases were normal. 2 patients underwent muscle biopsy that showed only atrophy and increased central nuclei. In three cases autosomal recessive inheritance (Becker, in one case autosomal dominant inheritance (Thomsen and in one case sporadic occurrence was suggested. With respect to successful results of carbamazepine therapy in 4 patients, and being excellent in one of them, we suggest carbamazepine for the first choice of Myotonia treatment.

  8. Monoclonal Antibodies to the Apical Chloride Channel in Necturus Gallbladder Inhibit the Chloride Conductance

    Science.gov (United States)

    Finn, Arthur L.; Tsai, Lih-Min; Falk, Ronald J.

    1989-10-01

    Monoclonal antibodies raised by injecting Necturus gallbladder cells into mice were tested for their ability to inhibit the apical chloride conductance induced by elevation of cellular cAMP. Five of these monoclonal antibodies bound to the apical cells, as shown by indirect immunofluorescence microscopy, and inhibited the chloride conductance; one antibody that bound only to subepithelial smooth muscle, by indirect immunofluorescence microscopy, showed no inhibition of chloride transport. The channel or a closely related molecule is present in the membrane whether or not the pathway is open, since, in addition to inhibiting the conductance of the open channel, the antibody also bound to the membrane in the resting state and prevented subsequent opening of the channel. The antibody was shown to recognize, by ELISA, epitopes from the Necturus gallbladder and small intestine. Finally, by Western blot analysis of Necturus gallbladder homogenates, the antibody was shown to recognize two protein bands of Mr 219,000 and Mr 69,000. This antibody should permit isolation and characterization of this important ion channel.

  9. Phosphatase inhibitors activate normal and defective CFTR chloride channels.

    OpenAIRE

    Becq, F; Jensen, T J; Chang, X B; Savoia, A.; Rommens, J M; Tsui, L C; Buchwald, M; Riordan, J R; Hanrahan, J W

    1994-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is regulated by phosphorylation and dephosphorylation at multiple sites. Although activation by protein kinases has been studied in some detail, the dephosphorylation step has received little attention. This report examines the mechanisms responsible for the dephosphorylation and spontaneous deactivation ("rundown") of CFTR chloride channels excised from transfected Chinese hamster ovary (CHO) and human airway epi...

  10. Purification and reconstitution of chloride channels from kidney and trachea

    International Nuclear Information System (INIS)

    Chloride channels mediate absorption and secretion of fluid in epithelia, and the regulation of these channels is now known to be defective in cystic fibrosis. Indanyl-oxyacetic acid 94 (IAA-94) is a high-affinity ligand for the chloride channel, and an affinity resin based on that structure was developed. Solubilized proteins from kidney and trachea membranes were applied to the affinity matrix, and four proteins with apparent molecular masses of 97, 64, 40, and 27 kilodaltons were eluted from the column by excess IAA-94. A potential-dependent 36Cl- uptake was observed after reconstituting these proteins into liposomes. Three types of chloride channels with single-channel conductances of 26, 100, and 400 picosiemens were observed after fusion of these liposomes with planar lipid bilayers. Similar types of chloride channels have been observed in epithelia

  11. Chloride dependence of hyperpolarization-activated chloride channel gates.

    Science.gov (United States)

    Pusch, M; Jordt, S E; Stein, V; Jentsch, T J

    1999-03-01

    1. ClC proteins are a class of voltage-dependent Cl- channels with several members mutated in human diseases. The prototype ClC-0 Torpedo channel is a dimeric protein; each subunit forms a pore that can gate independently from the other one. A common slower gating mechanism acts on both pores simultaneously; slow gating activates ClC-0 at hyperpolarized voltages. The ClC-2 Cl- channel is also activated by hyperpolarization, as are some ClC-1 mutants (e.g. D136G) and wild-type (WT) ClC-1 at certain pH values. 2. We studied the dependence on internal Cl- ([Cl-]i) of the hyperpolarization-activated gates of several ClC channels (WT ClC-0, ClC-0 mutant P522G, ClC-1 mutant D136G and an N-terminal deletion mutant of ClC-2), by patch clamping channels expressed in Xenopus oocytes. 3. With all these channels, reducing [Cl-]i shifted activation to more negative voltages and reduced the maximal activation at most negative voltages. 4. We also investigated the external halide dependence of WT ClC-2 using two-electrode voltage-clamp recording. Reducing external Cl- ([Cl-]o) activated ClC-2 currents. Replacing [Cl-]o by the less permeant Br- reduced channel activity and accelerated deactivation. 5. Gating of the ClC-2 mutant K566Q in normal [Cl-]o resembled that of WT ClC-2 in low [Cl-]o, i.e. channels had a considerable open probability (Po) at resting membrane potential. Substituting external Cl- by Br- or I- led to a decrease in Po. 6. The [Cl-]i dependence of the hyperpolarization-activated gates of various ClC channels suggests a similar gating mechanism, and raises the possibility that the gating charge for the hyperpolarization-activated gate is provided by Cl-. 7. The external halide dependence of hyperpolarization-activated gating of ClC-2 suggests that it is mediated or modulated by anions as in other ClC channels. In contrast to the depolarization-activated fast gates of ClC-0 and ClC-1, the absence of Cl- favours channel opening. Lysine 556 may be important for the

  12. Chloride Channels: Often enigmatic, rarely predictable

    Science.gov (United States)

    Duran, Charity; Thompson, Christopher H.; Xiao, Qinghuan; Hartzell, Criss

    2010-01-01

    Until recently, anion (Cl−) channels have received considerably less attention than cation channels. One reason for this may be that many Cl− channels perform functions that might be considered cell biological, like fluid secretion and cell volume regulation, whereas cation channels have historically been associated with cellular excitability that typically happens more rapidly. In this review, we discuss the recent explosion of interest in Cl− channels with special emphasis on new and often surprising developments over the last 5 years. This is exemplified by the findings that more than half of the ClC family members are antiporters, and not channels as was previously thought, and that bestrophins, previously prime candidates for Ca2+-activated Cl− channels, have been supplanted by the newly discovered anoctamins and now hold a tenuous position in the Cl− channel world. PMID:19827947

  13. Inhibition of nitrite-induced toxicity in channel catfish by calcium chloride and sodium chloride

    Science.gov (United States)

    Tommasso J.R., Wright, M. I.; Simco, B.A.; Davis, K.B.

    1980-01-01

    Environmental chloride has been shown to inhibit methemoglobin formation in fish, thereby offering a protective effect against nitrite toxicity. Channel catfish (Ictalurus punctatus) were simultaneously exposed to various environmental nitrite and chloride levels (as either CaCl2 or NaCl) in dechlorinated tap water (40 mg/L total hardness, 47 mg/L alkalinity, 4 mg/L chloride, pH = 6.9-7.1, and temperature 21-24°C). Methemoglobin levels in fish simultaneously exposed to 2.5 mg/L nitrite and up to 30 mg/L chloride as either CaCl2 or NaCl were similar but significantly lower than in unprotected fish. Exposure to 10 mg/L nitrite and 60 mg/L chloride resulted in methemoglobin levels similar to those of the controls; most unprotected fish died. Fish exposed to 10 mg/L nitrite had significantly lower methemoglobin levels when protected with 15.0 mg/L chloride as CaCl2 than with NaCl. Fish exposed to nitrite in the presence of 60 mg/L chloride (as either CaCl2 or NaCl) had similar 24-h LC50 values that were significantly elevated above those obtained in the absence of chloride. Calcium had little effect on tolerance to nitrite toxicity in channel catfish in contrast to its large effect reported in steelhead trout (Salmo gairdneri).

  14. Chloride channels of platelets%血小板氯通道

    Institute of Scientific and Technical Information of China (English)

    陈晓琳; 尹松梅

    2004-01-01

    Chloride channels distribute widely in the body, and participate in many physiological actions and regulatory processes. Based on their physiological roles and molecular structures, six kinds of chloride channels have been identified: (1) The chloride channels family; (2) Cystic fibrosis transmembrane conductance regulator; (3) Swelling-activated chloride channels; (4) Calcium-activated chloride channels; (5) The p64 (CLIC) gene family; (6) γ-aminobutyric acid and glycine receptors. The chloride channels do exist in platelets, and their appearances are dependent on the presence of intracellular calcium. Blocking agents of chloride channels inhibit the thrombin-activated platelet aggregation and the elevation of the intracellular calcium concentration in a dose-dependent manner. It is suggested that chloride channels play a role in the activation of platelets. In addition, chloride channels act on both the cell volume regulation and the intracellular pH regulation in platelets.

  15. A chloride channel in rat and human axons

    OpenAIRE

    Strupp, Michael; Grafe, Peter

    1991-01-01

    Current recordings from single chloride channels were obtained from excised and cell-attached patches of rat and human axons. In rat axons the channels showed an outwardly rectifying current-voltage relationship with a slope conductance of 33 pS at negative membrane potentials and 65 pS at positive potentials (symmetrical 150 mM CsCl). They were measurably for cations (PNa/PCs/PCl=0.1/0.2/1). Channel currents were independent of cytoplasmatic calcium concentration. Inactivation was not observ...

  16. The chloride channel inhibitor NS3736 [corrected] prevents bone resorption in ovariectomized rats without changing bone formation

    DEFF Research Database (Denmark)

    Schaller, Sophie; Henriksen, Kim; Sveigaard, Christina;

    2004-01-01

    Chloride channel activity is essential for osteoclast function. Consequently, inhibition of the osteoclastic chloride channel should prevent bone resorption. Accordingly, we tested a chloride channel inhibitor on bone turnover and found that it inhibits bone resorption without affecting bone form...

  17. Swell activated chloride channel function in human neutrophils

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, Michael D. [Leukocyte and Ion Channel Research Laboratory, School of Health and Biosciences, University of East London, Stratford Campus, London E15 4LZ (United Kingdom); Ahluwalia, Jatinder, E-mail: j.ahluwalia@uel.ac.uk [Leukocyte and Ion Channel Research Laboratory, School of Health and Biosciences, University of East London, Stratford Campus, London E15 4LZ (United Kingdom)

    2009-04-17

    Non-excitable cells such as neutrophil granulocytes are the archetypal inflammatory immune cell involved in critical functions of the innate immune system. The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential. For continuous function of the NADPH oxidase, I{sub e} has to be balanced to preserve electroneutrality, if not; sufficient depolarisation would prevent electrons from leaving the cell and neutrophil function would be abrogated. Subsequently, the depolarisation generated by the neutrophil NADPH oxidase I{sub e} must be counteracted by ion transport. The finding that depolarisation required counter-ions to compensate electron transport was followed by the observation that chloride channels activated by swell can counteract the NADPH oxidase membrane depolarisation. In this mini review, we discuss the research findings that revealed the essential role of swell activated chloride channels in human neutrophil function.

  18. Stable ATP binding mediated by a partial NBD dimer of the CFTR chloride channel

    OpenAIRE

    Tsai, Ming-Feng; Li, Min; Hwang, Tzyh-Chang

    2010-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR), a member of the adenosine triphosphate (ATP) binding cassette (ABC) superfamily, is an ATP-gated chloride channel. Like other ABC proteins, CFTR encompasses two nucleotide binding domains (NBDs), NBD1 and NBD2, each accommodating an ATP binding site. It is generally accepted that CFTR’s opening–closing cycles, each completed within 1 s, are driven by rapid ATP binding and hydrolysis events in NBD2. Here, by recording CFTR currents in...

  19. A synthetic chloride channel restores chloride conductance in human cystic fibrosis epithelial cells.

    Directory of Open Access Journals (Sweden)

    Bing Shen

    Full Text Available Mutations in the gene-encoding cystic fibrosis transmembrane conductance regulator (CFTR cause defective transepithelial transport of chloride (Cl(- ions and fluid, thereby becoming responsible for the onset of cystic fibrosis (CF. One strategy to reduce the pathophysiology associated with CF is to increase Cl(- transport through alternative pathways. In this paper, we demonstrate that a small synthetic molecule which forms Cl(- channels to mediate Cl(- transport across lipid bilayer membranes is capable of restoring Cl(- permeability in human CF epithelial cells; as a result, it has the potential to become a lead compound for the treatment of human diseases associated with Cl(- channel dysfunction.

  20. [Polymethoxylated flavonoids activate cystic fibrosis transmembrane conductance regulator chloride channel].

    Science.gov (United States)

    Cao, Huan-Huan; Fang, Fang; Yu, Bo; Luan, Jian; Jiang, Yu; Yang, Hong

    2015-04-25

    Cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent chloride channel, plays key roles in fluid secretion in serous epithelial cells. Previously, we identified two polymethoxylated flavonoids, 3',4',5,5',6,7-hexamethoxyflavone (HMF) and 5-hydroxy-6,7,3',4'-tetramethoxyflavone (HTF) which could potentiate CFTR chloride channel activities. The present study was aimed to investigate the potentiation effects of HMF and HTF on CFTR Cl(-) channel activities by using a cell-based fluorescence assay and the short circuit Ussing chamber assay. The results of cell-based fluorescence assay showed that both HMF and HTF could dose-dependently potentiate CFTR Cl(-) channel activities in rapid and reversible ways, and the activations could be reversed by the CFTR blocker CFTRinh-172. Notably, HMF showed the highest affinity (EC50 = 2 μmol/L) to CFTR protein among the flavonoid CFTR activators identified so far. The activation of CFTR by HMF or HTF was forskolin (FSK) dependent. Both compounds showed additive effect with FSK and 3-Isobutyl-1-methylx (IBMX) in the activation of CFTR, while had no additive effect with genistein (GEN). In ex vivo studies, HMF and HTF could stimulate transepithelial Cl(-) secretion in rat colonic mucosa and enhance fluid secretion in mouse trachea submucosal glands. These results suggest that HMF and HTF may potentiate CFTR Cl(-) channel activities through both elevation of cAMP level and binding to CFTR protein pathways. The results provide new clues in elucidating structure and activity relationship of flavonoid CFTR activators. HMF might be developed as a new drug in the therapy of CFTR-related diseases such as bronchiectasis and habitual constipation. PMID:25896054

  1. Functional modifications of acid-sensing ion channels by ligand-gated chloride channels.

    Directory of Open Access Journals (Sweden)

    Xuanmao Chen

    Full Text Available Together, acid-sensing ion channels (ASICs and epithelial sodium channels (ENaC constitute the majority of voltage-independent sodium channels in mammals. ENaC is regulated by a chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR. Here we show that ASICs were reversibly inhibited by activation of GABA(A receptors in murine hippocampal neurons. This inhibition of ASICs required opening of the chloride channels but occurred with both outward and inward GABA(A receptor-mediated currents. Moreover, activation of the GABA(A receptors modified the pharmacological features and kinetic properties of the ASIC currents, including the time course of activation, desensitization and deactivation. Modification of ASICs by open GABA(A receptors was also observed in both nucleated patches and outside-out patches excised from hippocampal neurons. Interestingly, ASICs and GABA(A receptors interacted to regulate synaptic plasticity in CA1 hippocampal slices. The activation of glycine receptors, which are similar to GABA(A receptors, also modified ASICs in spinal neurons. We conclude that GABA(A receptors and glycine receptors modify ASICs in neurons through mechanisms that require the opening of chloride channels.

  2. CFTR chloride channel as a molecular target of anthraquinone compounds in herbal laxatives

    Institute of Scientific and Technical Information of China (English)

    Hong YANG; Li-na XU; Cheng-yan HE; Xin LIU; Rou-yu FANG; Tong-hui MA

    2011-01-01

    Aim: To clarify whether CFTR is a molecular target of intestinal fluid secretion caused by the anthraquinone compounds from laxative herbal plants.Methods: A cell-based fluorescent assay to measure I- influx through CFTR chloride channel. A short-circuit current assay to measure transcellular Cl- current across single layer FRT cells and freshly isolated colon mucosa. A closed loop experiment to measure colon fluid secretion in vivo.Results: Anthraquinone compounds rhein, aloe-emodin and 1,8-dihydroxyanthraquinone (DHAN) stimulated l- influx through CFTR chloride channel in a dose-dependent manner in the presence of physiological concentration of cAMP. In the short-circuit current assay,the three compound enhanced Cl- currents in epithelia formed by CFTR-expressing FRT cells with EC5o values of 73±1.4, 56±1.7, and 50±0.5 μmol/L, respectively, and Rhein also enhanced Cl- current in freshly isolated rat colonic mucosa with a similar potency. These effects were completely reversed by the CFTR selective blocker CFTRinh-172. In in vivo closed loop experiments, rhein 2 mmol/L stimu-lated colonic fluid accumulation that was largely blocked by CFTRinh-172. The anthraquinone compounds did not elevate cAMP level in cultured FRT cells and rat colonic mucosa, suggesting a direct effect on CFTR activity.Conclusion: Natural anthraquinone compounds in vegetable laxative drugs are CFTR potsntiators that stimulated colonic chloride and fluid secretion. Thus CFTR chloride channel is a molecular target of vegetable laxative drugs.

  3. Cystic fibrosis transmembrane conductance regulator and the outwardly rectifying chloride channel: a relationship between two chloride channels expressed in epithelial cells.

    Science.gov (United States)

    Hryciw, D H; Guggino, W B

    2000-11-01

    1. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) result in the primary defect observed in patients with cystic fibrosis. 2. The CFTR is a member of the ATPase-binding cassette (ABC) transporter family but, unlike other members of this group, CFTR conducts a chloride current that is activated by cAMP. 3. In epithelial cells, the cAMP-stimulated chloride current is conducted by both CFTR and the outwardly rectifying chloride channel (ORCC). 4. The present review summarizes the current knowledge of the properties of the two channels, as well as their relationship. Because the gene encoding the ORCC has not been identified, a discussion as to possible candidates for this chloride channel is included. PMID:11071305

  4. Monoclonal antibodies to the apical chloride channel in Necturus gallbladder inhibit the chloride conductance.

    OpenAIRE

    Finn, A L; Tsai, L M; Falk, R J

    1989-01-01

    Monoclonal antibodies raised by injecting Necturus gallbladder cells into mice were tested for their ability to inhibit the apical chloride conductance induced by elevation of cellular cAMP. Five of these monoclonal antibodies bound to the apical cells, as shown by indirect immunofluorescence microscopy, and inhibited the chloride conductance; one antibody that bound only to subepithelial smooth muscle, by indirect immunofluorescence microscopy, showed no inhibition of chloride transport. The...

  5. Insecticide sensitivity of native chloride and sodium channels in a mosquito cell line.

    Science.gov (United States)

    Jenson, Lacey J; Anderson, Troy D; Bloomquist, Jeffrey R

    2016-06-01

    The aim of this study was to investigate the utility of cultured Anopheles gambiae Sua1B cells for insecticide screening applications without genetic engineering or other treatments. Sua1B cells were exposed to the known insecticidal compounds lindane and DIDS, which inhibited cell growth at micromolar concentrations. In patch clamp studies, DIDS produced partial inhibition (69%) of chloride current amplitudes, and an IC50 of 5.1μM was determined for Sua1B cells. A sub-set of chloride currents showed no response to DIDS; however, inhibition (64%) of these currents was achieved using a low chloride saline solution, confirming their identity as chloride channels. In contrast, lindane increased chloride current amplitude (EC50=116nM), which was reversed when cells were bathed in calcium-free extracellular solution. Voltage-sensitive chloride channels were also inhibited by the presence of fenvalerate, a type 2 pyrethroid, but not significantly blocked by type 1 allethrin, an effect not previously shown in insects. Although no evidence of fast inward currents typical of sodium channels was observed, studies with fenvalerate in combination with veratridine, a sodium channel activator, revealed complete inhibition of cell growth that was best fit by a two-site binding model. The high potency effect was completely inhibited in the presence of tetrodotoxin, a specific sodium channel blocker, suggesting the presence of some type of sodium channel. Thus, Sua1B cells express native insect ion channels with potential utility for insecticide screening. PMID:27155485

  6. Anoctamin Calcium-Activated Chloride Channels May Modulate Inhibitory Transmission in the Cerebellar Cortex.

    Directory of Open Access Journals (Sweden)

    Weiping Zhang

    Full Text Available Calcium-activated chloride channels of the anoctamin (alias TMEM16 protein family fulfill critical functions in epithelial fluid transport, smooth muscle contraction and sensory signal processing. Little is known, however, about their contribution to information processing in the central nervous system. Here we examined the recent finding that a calcium-dependent chloride conductance impacts on GABAergic synaptic inhibition in Purkinje cells of the cerebellum. We asked whether anoctamin channels may underlie this chloride conductance. We identified two anoctamin channel proteins, ANO1 and ANO2, in the cerebellar cortex. ANO1 was expressed in inhibitory interneurons of the molecular layer and the granule cell layer. Both channels were expressed in Purkinje cells but, while ANO1 appeared to be retained in the cell body, ANO2 was targeted to the dendritic tree. Functional studies confirmed that ANO2 was involved in a calcium-dependent mode of ionic plasticity that reduces the efficacy of GABAergic synapses. ANO2 channels attenuated GABAergic transmission by increasing the postsynaptic chloride concentration, hence reducing the driving force for chloride influx. Our data suggest that ANO2 channels are involved in a Ca2+-dependent regulation of synaptic weight in GABAergic inhibition. Thus, in balance with the chloride extrusion mechanism via the co-transporter KCC2, ANO2 appears to regulate ionic plasticity in the cerebellum.

  7. Function of chloride intracellular channel 1 in gastric cancer cells

    Directory of Open Access Journals (Sweden)

    Bo-Pei Li

    2012-01-01

    Full Text Available AIM: To investigate the effect of chloride intracellular channel 1 (CLIC1 on the cell proliferation, apoptosis, migration and invasion of gastric cancer cells. METHODS: CLIC1 expression was evaluated in human gastric cancer cell lines SGC-7901 and MGC-803 by real time polymerase chain reaction (RT-PCR. Four segments of small interference RNA (siRNA targeting CLIC1 mRNA and a no-sense control segment were designed by bioinformatics technology. CLIC1 siRNA was selected using Lipofectamine 2000 and transfected transiently into human gastric cancer SGC-7901 and MGC-803 cells. The transfected efficiency was observed under fluorescence microscope. After transfection, mRNA expression of CLIC1 was detected with RT-PCR and Western blotting was used to detect the protein expression. Proliferation was examined by methyl thiazolyl tetrazolium and apoptosis was detected with flow cytometry. Polycarbonate membrane transwell chamber and Matrigel were used for the detection of the changes of invasion and migration of the two cell lines. RESULTS: In gastric cancer cell lines SGC-7901 and MGC-803, CLIC1 was obviously expressed and CLIC1 siRNA could effectively suppress the expression of CLIC1 protein and mRNA. Proliferation of cells transfected with CLIC1 siRNA3 was enhanced notably, and the highest proliferation rate was 23.3% (P = 0.002 in SGC-7901 and 35.55% (P = 0.001 in MGC-803 cells at 48 h. The G2/M phase proportion increased, while G0/G1 and S phase proportions decreased. The apoptotic rate of the CLIC1 siRNA3 group obviously decreased in both SGC-7901 cells (62.24%, P = 0.000 and MGC-803 cells (52.67%, P = 0.004. Down-regulation of CLIC1 led to the inhibition of invasion and migration by 54.31% (P = 0.000 and 33.62% (P = 0.001 in SGC-7901 and 40.74% (P = 0.000 and 29.26% (P = 0.002 in MGC-803. However, there was no significant difference between the mock group cells and the negative control group cells. CONCLUSION: High CLIC1 expression can efficiently

  8. Function of chloride intracellular channel 1 in gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Peng-Fei Ma; Jun-Qiang Chen; Zhen Wang; Jin-Lu Liu; Bo-Pei Li

    2012-01-01

    AIM:To investigate the effect of chloride intracellular channel 1 (CLIC1) on the cell proliferation,apoptosis,migration and invasion of gastric cancer cells.METHODS:CLIC1 expression was evaluated in human gastric cancer cell lines SGC-7901 and MGC-803 by real time polymerase chain reaction (RT-PCR).Four segments of small interference RNA (siRNA) targeting CLIC1 mRNA and a no-sense control segment were designed by bioinformatics technology.CLIC1 siRNA was selected using Lipofectamine 2000 and transfected transiently into human gastric cancer SGC-7901 and MGC-803 cells.The transfected efficiency was observed under fluorescence microscope.After transfection,mRNA expression of CLIC1 was detected with RT-PCR and Western blotting was used to detect the protein expression.Proliferation was examined by methyl thiazolyl tetrazolium and apoptosis was detected with flow cytometry.Polycarbonate membrane transwell chamber and Matrigel were used for the detection of the changes of invasion and migration of the two cell lines.RESULTS:In gastric cancer cell lines SGC-7901 and MGC-803,CLIC1 was obviously expressed and CLIC1 siRNA could effectively suppress the expression of CLIC1 protein and mRNA.Proliferation of cells transfected with CLIC1 siRNA3 was enhanced notably,and the highest proliferation rate was 23.3% (P =0.002) in SGC-7901 and 35.55% (P =0.001) in MGC-803 cells at 48 h.The G2/M phase proportion increased,while G0/G1 and S phase proportions decreased.The apoptotic rate of the CLIC1 siRNA3 group obviously decreased in both SGC-7901 cells (62.24%,P =0.000) and MGC-803 cells (52.67%,P =0.004).Down-regulation of CLIC1 led to the inhibition of invasion and migration by 54.31% (P =0.000) and 33.62% (P =0.001) in SGC-7901 and 40.74% (P =0.000) and 29.26% (P =0.002) in MGC-803.However,there was no significant difference between the mock group cells and the negative control group cells.CONCLUSION:High CLIC1 expression can efficiently inhibit proliferation and

  9. 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

  10. Mechanism of HERG potassium channel inhibition by tetra-n-octylammonium bromide and benzethonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Long, Yan; Lin, Zuoxian [Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Xia, Menghang; Zheng, Wei [National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892 (United States); Li, Zhiyuan, E-mail: li_zhiyuan@gibh.ac.cn [Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China)

    2013-03-01

    Tetra-n-octylammonium bromide and benzethonium chloride are synthetic quaternary ammonium salts that are widely used in hospitals and industries for the disinfection and surface treatment and as the preservative agent. Recently, the activities of HERG channel inhibition by these compounds have been found to have potential risks to induce the long QT syndrome and cardiac arrhythmia, although the mechanism of action is still elusive. This study was conducted to investigate the mechanism of HERG channel inhibition by these compounds by using whole-cell patch clamp experiments in a CHO cell line stably expressing HERG channels. Tetra-n-octylammonium bromide and benzethonium chloride exhibited concentration-dependent inhibitions of HERG channel currents with IC{sub 50} values of 4 nM and 17 nM, respectively, which were also voltage-dependent and use-dependent. Both compounds shifted the channel activation I–V curves in a hyperpolarized direction for 10–15 mV and accelerated channel activation and inactivation processes by 2-fold. In addition, tetra-n-octylammonium bromide shifted the inactivation I–V curve in a hyperpolarized direction for 24.4 mV and slowed the rate of channel deactivation by 2-fold, whereas benzethonium chloride did not. The results indicate that tetra-n-octylammonium bromide and benzethonium chloride are open-channel blockers that inhibit HERG channels in the voltage-dependent, use-dependent and state-dependent manners. - Highlights: ► Tetra-n-octylammonium and benzethonium are potent HERG channel inhibitors. ► Channel activation and inactivation processes are accelerated by the two compounds. ► Both compounds are the open-channel blockers to HERG channels. ► HERG channel inhibition by both compounds is use-, voltage- and state dependent. ► The in vivo risk of QT prolongation needs to be studied for the two compounds.

  11. Identification of Herbal Compound lmperatorin with Adverse Effects on ANO1 and CFTR Chloride Channels

    Institute of Scientific and Technical Information of China (English)

    HAO Feng; YI Fei; ZHANG Di; NING Yan; SU Wei-heng; FENG Xue-chao; YANG Hong; MA Tong-hui

    2011-01-01

    Calcium-activated chloride channels(CaCCs) are the crucial regulators of transepithelial fluid secretion,smooth muscle contraction and sensory transduction. Recently, compelling evidence has indicated that TMEM 16A(ANO 1 or anoctamin-i ) is a bona fide calcium-acvtivated chloride channel. A few small molecule CaCCs regulators are available for functional and therapeutic studies. We screened 126 natural compounds from Chinese herbs. Screening was performed with an iodide influx assay in Fischer rat thyroid epithelial cells to coexpress ANOI and an iodide-sensitive fluorescent indicator(EYFP-HI48Q/I152L). lmperatorin, a coumarin compound, was identifled to inhibit ANOl-mediated chloride transport activated by multiple calcium-elevating agonists. The inhibitory effect is dose-dependent with IC50 ~14.63 μmol/L. Interestingly, imperatorin activated CFTR chloride channel with EC50 ~35.52 μmol/L. The adverse effects of imperatorin on CaCC and CFTR chloride channels will make it useful in pharmacological dissection of chloride transport in airway and intestinal epithelium. Further studies are required to evaluate the therapeutic effects of imperatorin on hypertension, asthma and certain tumors.

  12. A solid phase honey-like channel method for synthesizing urea-ammonium chloride cocrystals on industrial scale

    Science.gov (United States)

    Xue, Bingchun; Mao, Meiling; Liu, Yanhong; Guo, Jinyu; Li, Jing; Liu, Erbao

    2016-05-01

    Unanticipated a new and simple urea-ammonium chloride cocrystal synthesis method on industrial scale was found during attempts to produce a kind of granulated compound fertilizer. The aggregation of fertilizer powder can make the interaction among particles from loose to close, which generate mechanical pressure and in turn act as the driving force to benefit cocrystal growth. Additionally, the honeycomb-like channels constructed by other coexisting compound make the water evaporates more moderate, which can help the formation of supersaturated solution at suitable rate, further promote the growth of cocrystal. This approach possibly opens a new route toward the developing methodologies for cocrystal synthesis.

  13. Myotonia Congenita Mutation Enhances the Degradation of Human CLC-1 Chloride Channels

    OpenAIRE

    Lee, Ting-Ting; Zhang, Xiao-Dong; Chuang, Chao-Chin; Chen, Jing-Jer; Chen, Yi-An; Chen, Shu-Ching; Chen, Tsung-Yu; Tang, Chih-Yung

    2013-01-01

    Myotonia congenita is a hereditary muscle disorder caused by mutations in the human voltage-gated chloride (Cl−) channel CLC-1. Myotonia congenita can be inherited in an autosomal recessive (Becker type) or dominant (Thomsen type) fashion. One hypothesis for myotonia congenita is that the inheritance pattern of the disease is determined by the functional consequence of the mutation on the gating of CLC-1 channels. Several disease-related mutations, however, have been shown to yield functional...

  14. Novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids as calcium activated chloride channel inhibitors

    OpenAIRE

    Kumar, Satish; Namkung, Wan; A S Verkman; Sharma, Pawan K

    2012-01-01

    Transmembrane protein 16A (TMEM16A) channels are recently discovered membrane proteins that functions as a calcium activated chloride channel (CaCC). CaCCs are major regulators of various physiological processes, such as sensory transduction, epithelial secretion, smooth muscle contraction and oocyte fertilization. Thirty novel 5-substituted benzyloxy-2-arylbenzofuran-3-carboxylic acids (B01–B30) were synthesized and evaluated for their TMEM16A inhibitory activity by using short circuit curre...

  15. An improved ivermectin-activated chloride channel receptor for inhibiting electrical activity in defined neuronal populations

    DEFF Research Database (Denmark)

    Lynagh, Timothy Peter; Lynch, Joseph W

    2010-01-01

    for surgically implanted stimulus delivery methods and their use of nonhuman receptors. A third silencing method, an invertebrate glutamate-gated chloride channel receptor (GluClR) activated by ivermectin, solves the stimulus delivery problem as ivermectin is a safe, well tolerated drug that reaches...

  16. Simultaneous optical recording in multiple cells by digital holographic microscopy of chloride current associated to activation of the ligand-gated chloride channel GABA(A receptor.

    Directory of Open Access Journals (Sweden)

    Pascal Jourdain

    Full Text Available Chloride channels represent a group of targets for major clinical indications. However, molecular screening for chloride channel modulators has proven to be difficult and time-consuming as approaches essentially rely on the use of fluorescent dyes or invasive patch-clamp techniques which do not lend themselves to the screening of large sets of compounds. To address this problem, we have developed a non-invasive optical method, based on digital holographic microcopy (DHM, allowing monitoring of ion channel activity without using any electrode or fluorescent dye. To illustrate this approach, GABA(A mediated chloride currents have been monitored with DHM. Practically, we show that DHM can non-invasively provide the quantitative determination of transmembrane chloride fluxes mediated by the activation of chloride channels associated with GABA(A receptors. Indeed through an original algorithm, chloride currents elicited by application of appropriate agonists of the GABA(A receptor can be derived from the quantitative phase signal recorded with DHM. Finally, chloride currents can be determined and pharmacologically characterized non-invasively simultaneously on a large cellular sampling by DHM.

  17. Chloride channels in the small intestinal cell line IEC-18.

    Science.gov (United States)

    Basavappa, Srisaila; Vulapalli, Sreesatya Raju; Zhang, Hui; Yule, David; Coon, Steven; Sundaram, Uma

    2005-01-01

    Small intestinal crypt cells play a critical role in modulating Cl- secretion during digestion. The types of Cl- channels mediating Cl- secretion in the small intestine was investigated using the intestinal epithelial cell line, IEC-18, which was derived from rat small intestine crypt cells. In initial radioisotope efflux studies, exposure to forskolin, ionomycin or a decrease in extracellular osmolarity significantly increased 36Cl efflux as compared to control cells. Whole cell patch clamp techniques were subsequently used to examine in more detail the swelling-, Ca2+-, and cAMP-activated Cl- conductance. Decreasing the extracellular osmolarity from 290 to 200 mOsm activated a large outwardly rectifying Cl- current that was voltage-independent and had an anion selectivity of I- > Cl-. Increasing cytosolic Ca2+ by ionomycin activated whole cell Cl- currents, which were also outwardly rectifying but were voltage-dependent. The increase in intracellular Ca2+ levels with ionomycin was confirmed with fura-2 loaded IEC-18 cells. A third type of whole cell Cl- current was observed after increases in intracellular cAMP induced by forskolin. These cAMP-activated Cl- currents have properties consistent with cystic fibrosis transmembrane regulator (CFTR) Cl- channels, as the currents were blocked by glibenclamide or NPPB but insensitive to DIDS. In addition, the current-voltage relationship was linear and had an anion selectivity of Cl- > I-. Confocal immunofluorescence studies and Western blots with two different anti-CFTR antibodies confirmed the expression of CFTR. These results suggest that small intestinal crypt cells express multiple types of Cl- channels, which may all contribute to net Cl- secretion. PMID:15389550

  18. Shikonin Inhibits Intestinal Calcium-Activated Chloride Channels and Prevents Rotaviral Diarrhea.

    Science.gov (United States)

    Jiang, Yu; Yu, Bo; Yang, Hong; Ma, Tonghui

    2016-01-01

    Secretory diarrhea remains a global health burden and causes major mortality in children. There have been some focuses on antidiarrheal therapies that may reduce fluid losses and intestinal motility in diarrheal diseases. In the present study, we identified shikonin as an inhibitor of TMEM16A chloride channel activity using cell-based fluorescent-quenching assay. The IC50 value of shikonin was 6.5 μM. Short-circuit current measurements demonstrated that shikonin inhibited Eact-induced Cl(-) current in a dose-dependent manner, with IC50 value of 1.5 μM. Short-circuit current measurement showed that shikonin exhibited inhibitory effect against CCh-induced Cl(-) currents in mouse colonic epithelia but did not affect cytoplasmic Ca(2+) concentration as well as the other major enterocyte chloride channel conductance regulator. Characterization study found that shikonin inhibited basolateral K(+) channel activity without affecting Na(+)/K(+)-ATPase activities. In vivo studies revealed that shikonin significantly delayed intestinal motility in mice and reduced stool water content in a neonatal mice model of rotaviral diarrhea without affecting the viral infection process in vivo. Taken together, the results suggested that shikonin inhibited enterocyte calcium-activated chloride channels, the inhibitory effect was partially through inhbition of basolateral K(+) channel activity, and shikonin could be a lead compound in the treatment of rotaviral secretory diarrhea. PMID:27601995

  19. Cystic fibrosis transmembrane conductance regulator chloride channel blockers: Pharmacological, biophysical and physiological relevance

    Institute of Scientific and Technical Information of China (English)

    Paul; Linsdell

    2014-01-01

    Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of

  20. Inhibition of herpes simplex virus type 1 entry by chloride channel inhibitors tamoxifen and NPPB

    International Nuclear Information System (INIS)

    Highlights: • We analyze the anti-HSV potential of chloride channel inhibitors. • Tamoxifen and NPPB show anti-HSV-1 and anti-ACV-resistant HSV-1 activities. • HSV-1 infection induces intracellular chloride concentration increasing. • Tamoxifen and NPPB inhibit HSV-1 early infection. • Tamoxifen and NPPB prevent the fusion process of HSV-1. - Abstract: Herpes simplex virus type 1 (HSV-1) infection is very common worldwide and can cause significant health problems from periodic skin and corneal lesions to encephalitis. Appearance of drug-resistant viruses in clinical therapy has made exploring novel antiviral agents emergent. Here we show that chloride channel inhibitors, including tamoxifen and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB), exhibited extensive antiviral activities toward HSV-1 and ACV-resistant HSV viruses. HSV-1 infection induced chloride ion influx while treatment with inhibitors reduced the increase of intracellular chloride ion concentration. Pretreatment or treatment of inhibitors at different time points during HSV-1 infection all suppressed viral RNA synthesis, protein expression and virus production. More detailed studies demonstrated that tamoxifen and NPPB acted as potent inhibitors of HSV-1 early entry step by preventing viral binding, penetration and nuclear translocation. Specifically the compounds appeared to affect viral fusion process by inhibiting virus binding to lipid rafts and interrupting calcium homeostasis. Taken together, the observation that tamoxifen and NPPB can block viral entry suggests a stronger potential for these compounds as well as other ion channel inhibitors in antiviral therapy against HSV-1, especially the compound tamoxifen is an immediately actionable drug that can be reused for treatment of HSV-1 infections

  1. Inhibition of herpes simplex virus type 1 entry by chloride channel inhibitors tamoxifen and NPPB

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Kai [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of Life Science and Technology, Jinan University, Guangzhou (China); Chen, Maoyun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Xiang, Yangfei; Ma, Kaiqi [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Jin, Fujun [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); College of pharmacy, Jinan University, Guangzhou (China); Wang, Xiao [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Wang, Xiaoyan; Wang, Shaoxiang [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China); Wang, Yifei, E-mail: twang-yf@163.com [Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou (China)

    2014-04-18

    Highlights: • We analyze the anti-HSV potential of chloride channel inhibitors. • Tamoxifen and NPPB show anti-HSV-1 and anti-ACV-resistant HSV-1 activities. • HSV-1 infection induces intracellular chloride concentration increasing. • Tamoxifen and NPPB inhibit HSV-1 early infection. • Tamoxifen and NPPB prevent the fusion process of HSV-1. - Abstract: Herpes simplex virus type 1 (HSV-1) infection is very common worldwide and can cause significant health problems from periodic skin and corneal lesions to encephalitis. Appearance of drug-resistant viruses in clinical therapy has made exploring novel antiviral agents emergent. Here we show that chloride channel inhibitors, including tamoxifen and 5-nitro-2-(3-phenyl-propylamino) benzoic acid (NPPB), exhibited extensive antiviral activities toward HSV-1 and ACV-resistant HSV viruses. HSV-1 infection induced chloride ion influx while treatment with inhibitors reduced the increase of intracellular chloride ion concentration. Pretreatment or treatment of inhibitors at different time points during HSV-1 infection all suppressed viral RNA synthesis, protein expression and virus production. More detailed studies demonstrated that tamoxifen and NPPB acted as potent inhibitors of HSV-1 early entry step by preventing viral binding, penetration and nuclear translocation. Specifically the compounds appeared to affect viral fusion process by inhibiting virus binding to lipid rafts and interrupting calcium homeostasis. Taken together, the observation that tamoxifen and NPPB can block viral entry suggests a stronger potential for these compounds as well as other ion channel inhibitors in antiviral therapy against HSV-1, especially the compound tamoxifen is an immediately actionable drug that can be reused for treatment of HSV-1 infections.

  2. Design and Synthesis of Photoaffinity Probe Candidates for the GABA-gated Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    LIU Shang-Zhong; LI Qing-X.

    2006-01-01

    In order to characterize binding sites of insecticidal compounds on GABA gated chloride channel, new photoaffinity probe candidates based on 5e-t-butyl-2e-[4-(substituted-propynyl)phenyl]-1,3-dithiane for the noncompetitive blocker (NCB) site of the γ-aminobutyric acid (GABA)-gated chloride channel were designed and synthesized, and their potency as an inhibitor on NCB was measured by 4'-ethynyl-4-n-[2,3-3H2]-propylbicycloorthobenzoate (3H EBOB) assay. The synthesized compounds showed high inhibition activities with half maximum inhibition concentrations (IC50) of lower than 35 nmol/L and were very stable in binding conditions as well photoreacted quickly at 300 nm light. These new compounds are expected to be good photoaffinity labeling probes if radioisotope iodine is incorporated.

  3. Basolateral K+ channel involvement in forskolin-activated chloride secretion in human colon.

    Science.gov (United States)

    McNamara, B; Winter, D C; Cuffe, J E; O'Sullivan, G C; Harvey, B J

    1999-08-15

    1. In this study we investigated the role of basolateral potassium transport in maintaining cAMP-activated chloride secretion in human colonic epithelium. 2. Ion transport was quantified in isolated human colonic epithelium using the short-circuit current technique. Basolateral potassium transport was studied using nystatin permeabilization. Intracellular calcium measurements were obtained from isolated human colonic crypts using fura-2 spectrofluorescence imaging. 3. In intact isolated colonic strips, forskolin and prostaglandin E2 (PGE2) activated an inward transmembrane current (ISC) consistent with anion secretion (for forskolin DeltaISC = 63.8+/-6.2 microA cm(-2), n = 6; for PGE2 DeltaISC = 34.3+/-5.2 microA cm(-2), n = 6). This current was inhibited in chloride-free Krebs solution or by inhibiting basolateral chloride uptake with bumetanide and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid DIDS). 4. The forskolin- and PGE2-induced chloride secretion was inhibited by basolateral exposure to barium (5 mM), tetrapentylammonium (10 microM) and tetraethylammonium (10 mM). 5. The transepithelial current produced under an apical to serosal K+ gradient in nystatin-perforated colon is generated at the basolateral membrane by K+ transport. Forskolin failed to activate this current under conditions of high or low calcium and failed to increase the levels of intracellular calcium in isolated crypts 6. In conclusion, we propose that potassium recycling through basolateral K+ channels is essential for cAMP-activated chloride secretion. PMID:10432355

  4. Ligand-gated chloride channels are receptors for biogenic amines in C. elegans

    OpenAIRE

    Ringstad, Niels; Abe, Namiko; Horvitz, H. Robert

    2009-01-01

    Biogenic amines such as serotonin and dopamine are intercellular signaling molecules that function widely as neurotransmitters and neuromodulators. We have identified in the nematode Caenorhabditis elegans three ligand-gated chloride channels that are receptors for biogenic amines: LGC-53 is a high-affinity dopamine receptor, LGC-55 is a high-affinity tyramine receptor, and LGC-40 is a low-affinity serotonin receptor that is also gated by choline and acetylcholine. lgc-55 mutants are defectiv...

  5. Emerging role of cystic fibrosis transmembrane conductance regulator - an epithelial chloride channel in gastrointestinal cancers

    OpenAIRE

    Hou, Yuning; Guan, Xiaoqing; Yang, Zhe; Li, Chunying

    2016-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially...

  6. Activation Effect of Cathartic Natural Compound Rhein to CFTR Chloride Channel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel expressed in intestinal exocrine glands, which plays a key role in intestinal fluid secretion. A natural anthraquinone activator of CFTR Cl- channel, rhein, was identified by screening 217 single compounds from Chinese herbs via a cellbased halide-sensitive fluorescent assay. Rhein activates CFTR Cl- transportation in a dose-dependent manner in the presence of cAMP with a physiological concentration. This study provides a novel molecular pharmacological mechanism for the laxative drugs in Traditional Chinese Medicine such as aloe, cascara and senna.

  7. Oxidation and Reduction Control of the Inactivation Gating of Torpedo ClC-0 Chloride Channels

    OpenAIRE

    Li, Yong; Yu, Wei-Ping; Lin, Chia-Wei; Chen, Tsung-Yu

    2005-01-01

    Oxidation and reduction (redox) are known to modulate the function of a variety of ion channels. Here, we report a redox regulation of the function of ClC-0, a chloride (Cl−) channel from the Torpedo electric organ. The study was motivated by the occasional observation of oocytes with hyperpolarization-activated Cl− current when these oocytes expressed ClC-0. We find that these atypical recording traces can be turned into typical ClC-0 current by incubating the oocyte in millimolar concentrat...

  8. Cys-loop ligand-gated chloride channels in dorsal unpaired median neurons of Locusta migratoria.

    Science.gov (United States)

    Janssen, Daniel; Derst, Christian; Rigo, Jean-Michel; Van Kerkhove, Emmy

    2010-05-01

    In insects, inhibitory neurotransmission is generally associated with members of the cys-loop ligand-gated anion channels, such as the glutamate-gated chloride channel (GluCl), the GABA-gated chloride channels (GABACl), and the histamine-gated chloride channels (HisCl). These ionotropic receptors are considered established target sites for the development of insecticides, and therefore it is necessary to obtain a better insight in their distribution, structure, and functional properties. Here, by combining electrophysiology and molecular biology techniques, we identified and characterized GluCl, GABACl, and HisCl in dorsal unpaired median (DUM) neurons of Locust migratoria. In whole cell patch-clamp recordings, application of glutamate, GABA, or histamine induced rapidly activating ionic currents. GluCls were sensitive to ibotenic acid and blocked by picrotoxin and fipronil. The pharmacological profile of the L. migratoria GABACl fitted neither the vertebrate GABA(A) nor GABA(C) receptor and was similar to the properties of the cloned Drosophila melanogaster GABA receptor subunit (Rdl). The expression of Rdl-like subunit-containing GABA receptors was shown at the molecular level using RT-PCR. Sequencing analysis indicated that the orthologous GABACl of D. melanogaster CG10357-A is expressed in DUM neurons of L. migratoria. Histamine-induced currents exhibited a fast onset and desensitized completely on continuous application of histamine. In conclusion, within the DUM neurons of L. migratoria, we identified three different cys-loop ligand-gated anion channels that use GABA, glutamate, or histamine as their neurotransmitter. PMID:20200125

  9. Enhancement of an outwardly rectifying chloride channel in hippocampal pyramidal neurons after cerebral ischemia.

    Science.gov (United States)

    Li, Jianguo; Chang, Quanzhong; Li, Xiaoming; Li, Xiawen; Qiao, Jiantian; Gao, Tianming

    2016-08-01

    Cerebral ischemia induces delayed, selective neuronal death in the CA1 region of the hippocampus. The underlying molecular mechanisms remain unclear, but it is known that apoptosis is involved in this process. Chloride efflux has been implicated in the progression of apoptosis in various cell types. Using both the inside-out and whole-cell configurations of the patch-clamp technique, the present study characterized an outwardly rectifying chloride channel (ORCC) in acutely dissociated pyramid neurons in the hippocampus of adult rats. The channel had a nonlinear current-voltage relationship with a conductance of 42.26±1.2pS in the positive voltage range and 18.23±0.96pS in the negative voltage range, indicating an outward rectification pattern. The channel is Cl(-) selective, and the open probability is voltage-dependent. It can be blocked by the classical Cl(-) channel blockers DIDS, SITS, NPPB and glibenclamide. We examined the different changes in ORCC activity in CA1 and CA3 pyramidal neurons at 6, 24 and 48h after transient forebrain ischemia. In the vulnerable CA1 neurons, ORCC activity was persistently enhanced after ischemic insult, whereas in the invulnerable CA3 neurons, no significant changes occurred. Further analysis of channel kinetics suggested that multiple openings are a major contributor to the increase in channel activity after ischemia. Pharmacological blockade of the ORCC partly attenuated cell death in the hippocampal neurons. We propose that the enhanced activity of ORCC might contribute to selective neuronal damage in the CA1 region after cerebral ischemia, and that ORCC may be a therapeutic target against ischemia-induced cell death. PMID:27181516

  10. The Granular Chloride Channel ClC-3 Is Permissive For Insulin Secretion

    OpenAIRE

    Deriy, Ludmila V.; Gomez, Erwin A.; Jacobson, David A.; Wang, Xueqing; Hopson, Jessika A.; Liu, Xiang Y.; Zhang, Guangping; Bindokas, Vytautas P.; Philipson, Louis H.; Nelson, Deborah J.

    2009-01-01

    Insulin secretion from pancreatic β–cells is dependent on maturation and acidification of the secretory granule necessary for prohormone convertase cleavage of proinsulin. Previous studies in isolated β–cells revealed that acidification may be dependent on the granule membrane chloride channel ClC-3, in a step permissive for a regulated secretory response. In this study, immuno-electron microscopy of β–cells revealed colocalization of ClC-3 and insulin on secretory granules. Clc-3−/− mice as ...

  11. Chloride channel-dependent copper acquisition of laccase in the basidiomycetous fungus Cryptococcus neoformans

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The CLC chloride channel gene CLC-A of the pathogen yeast Cryptococcus neoformans was previously reported to be critical for multicopper laccase activity and growth at an elevated pH.This study reports that copper homeostasis was impaired in the clc-a mutant.This was demonstrated by the substantial decrease of the intracellular quantity of copper under copper-limited growth as determined by flame atomic absorption spectrometry.CLC-A is a critical factor in copper homeostasis which is required for copper acquisition of laccase in C.neoformans.

  12. Mitochondria-Rich Cells as Experimental Model in Studies of Epithelial Chloride Channels

    DEFF Research Database (Denmark)

    Willumsen, Niels J.; Amstrup, Jan; Møbjerg, Nadja;

    2002-01-01

    -actin localised in the submembrane domain in the neck region of the flask-shaped mr cell. (ii) The other identified Cl- pathway of mr cells is mediated by small-conductance apical CFTR chloride channels as concluded from its activation via ß-adrenergic receptors, ion selectivity, genistein stimulation and...... inhibition by glibenclamide. bbCFTR has been cloned, and immunostaining has shown that the gene product is selectively expressed in mr cells. There is cross-talk between the two pathways in the sense that activation of the conductance of the mr cell by voltage clamping excludes activation via receptor...

  13. Glutamate-activated chloride channels: Unique fipronil targets present in insects but not in mammals

    OpenAIRE

    NARAHASHI, Toshio; Zhao, Xilong; Ikeda, Tomoko; Salgado, Vincent L.; Yeh, Jay Z.

    2010-01-01

    Selectivity to insects over mammals is one of the important characteristics for a chemical to become a useful insecticide. Fipronil was found to block cockroach GABA receptors more potently than rat GABAA receptors. Furthermore, glutamate-activated chloride channels (GluCls), which are present in cockroaches but not in mammals, were very sensitive to the blocking action of fipronil. The IC50s of fipronil block were 30 nM in cockroach GABA receptors and 1600 nM in rat GABAA receptors. Moreover...

  14. Differential distribution of glutamate- and GABA-gated chloride channels in the housefly Musca domestica.

    Science.gov (United States)

    Kita, Tomo; Ozoe, Fumiyo; Azuma, Masaaki; Ozoe, Yoshihisa

    2013-09-01

    l-Glutamic acid (glutamate) mediates fast inhibitory neurotransmission by affecting glutamate-gated chloride channels (GluCls) in invertebrates. The molecular function and pharmacological properties of GluCls have been well studied, but not much is known about their physiological role and localization in the insect body. The distribution of GluCls in the housefly (Musca domestica L.) was thus compared with the distribution of γ-aminobutyric acid (GABA)-gated chloride channels (GABACls). Quantitative PCR and ligand-binding experiments indicate that the GluCl and GABACl transcripts and proteins are predominantly expressed in the adult head. Intense GluCl immunostaining was detected in the lamina, leg motor neurons, and legs of adult houseflies. The GABACl (Rdl) immunostaining was more widely distributed, and was found in the medulla, lobula, lobula plate, mushroom body, antennal lobe, and ellipsoid body. The present findings suggest that GluCls have physiological roles in different tissues than GABACls. PMID:23806605

  15. Synthesis and Characterization of A Small Molecule CFTR Chloride Channel Inhibitor

    Institute of Scientific and Technical Information of China (English)

    HE Cheng-yan; ZHANG Heng-jun; SU Zhong-min; ZHOU Jin-song; YANG Hong; MA Tong-hui

    2004-01-01

    A thiazolidinone CFTR inhibitor(CFTRinh-172) was synthesized by a three-step procedure with trifluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally by means of 1H NMR and functionally in a CFTR-expressing cell line FRT/hCFTR/EYFP-H148Q by both fluorescent and electrophysiological methods. A large amount(100 g) of high-quality small molecule thiazolidinone CFTR chloride channel inhibitor, CFTRinh-172, can be produced with this simple three-step synthetic procedure. The structure of the final product 2-thioxo-3-(3-trifluromethylphenyl)-5-[4-carboxyphenyl-methylene]-4-thiazolidinone was confirmed by 1H NMR. The overall yield was 58% with a purity over 99% as analyzed by HPLC. The synthesized CFTRinh-172 specifically inhibited CFTR chloride channel function in a cell-based fluorescence assay(Kd≈1.5 μmol/L) and in a Ussing chamber-based short-circuit current assay(Kd≈0.2 μmol/L), indicating better quality than that of the commercial combinatorial compound. The synthesized inhibitor is nontoxic to cultured cells at a high concentration and to mouse at a high dose. The synthetic procedure developed here can be used to produce a large amount of the high-quality CFTRinh-172 suitable for antidiarrheal studies and for creation of cystic fibrosis models in large animals. The procedure can be used to synthesize radiolabled CFTRinh-172 for in vivo pharmacokinetics studies.

  16. A High-affinity Activator of G551D-CFTR Chloride Channel Identified By High Throughput Screening

    Institute of Scientific and Technical Information of China (English)

    ZHAO Lu; HE Cheng-yan; LIU Yan-li; ZHOU Hong-lan; ZHOU Jin-song; SHANG De-jing; YANG Hong

    2004-01-01

    A stably transfected CHO cell line coexpressing G551D-CFTR and iodide-sensitive yellow fluorescent protein mutant EYFP-H148Q-I152L was successfully established and used as assay model to identify small-molecule activators of G551D-CFTR chloride channel from 100000 diverse combinatorial compounds by high throughput screening on a customized Beckman robotic system. A bicyclooctane compound was identified to activate G551D-CFTR chloride channel with high-affinity(Kd=1.8 μmol/L). The activity of the bicyclooctane compound is G551D-CFTR-specific, reversible and non-toxic. The G551D-CFTR activator may be useful as a tool to study the mutant G551D-CFTR chloride channel structure and transport properties and as a candidate drug to cure cystic fibrosis caused by G551D-CFTR mutation.

  17. Emerging role of cystic fibrosis transmembrane conductance regulator - an epithelial chloride channel in gastrointestinal cancers.

    Science.gov (United States)

    Hou, Yuning; Guan, Xiaoqing; Yang, Zhe; Li, Chunying

    2016-03-15

    Cystic fibrosis transmembrane conductance regulator (CFTR), a glycoprotein with 1480 amino acids, has been well established as a chloride channel mainly expressed in the epithelial cells of various tissues and organs such as lungs, sweat glands, gastrointestinal system, and reproductive organs. Although defective CFTR leads to cystic fibrosis, a common genetic disorder in the Caucasian population, there is accumulating evidence that suggests a novel role of CFTR in various cancers, especially in gastroenterological cancers, such as pancreatic cancer and colon cancer. In this review, we summarize the emerging findings that link CFTR with various cancers, with focus on the association between CFTR defects and gastrointestinal cancers as well as the underlying mechanisms. Further study of CFTR in cancer biology may help pave a new way for the diagnosis and treatment of gastrointestinal cancers. PMID:26989463

  18. Novel chloride channel gene mutations in two unrelated Chinese families with myotonia congenita

    Directory of Open Access Journals (Sweden)

    Gao Feng

    2010-12-01

    Full Text Available Myotonia congenita (MC is a genetic disease characterized by mutations in the muscle chloride channel gene (CLCN1. To date, approximately 130 different mutations on the CLCN1 gene have been identified. However, most of the studies have focused on Caucasians, and reports on CLCN1 mutations in Chinese population are rare. This study investigated the mutation of CLCN1 in two Chinese families with MC. Direct sequencing of the CLCN1 gene revealed a heterozygous mutation (892G>A, resulting in A298T in one family and a compound heterozygous mutations (782A>G, resulting in Y261C; 1679T>C, resulting in M560T in the other family, None of the 100 normal controls had these mutations. Our findings add more to the available information on the CLCN1 mutation spectrum, and provide a valuable reference for studying the mutation types and inheritance pattern of CLCN1 in the Chinese population.

  19. 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

  20. Participation of GABAA Chloride Channels in the Anxiolytic-Like Effects of a Fatty Acid Mixture

    Directory of Open Access Journals (Sweden)

    Juan Francisco Rodríguez-Landa

    2013-01-01

    Full Text Available Human amniotic fluid and a mixture of eight fatty acids (FAT-M identified in this maternal fluid (C12:0, lauric acid, 0.9 μg%; C14:0, myristic acid, 6.9 μg%; C16:0, palmitic acid, 35.3 μg%; C16:1, palmitoleic acid, 16.4 μg%; C18:0, stearic acid, 8.5 μg%; C18:1cis, oleic acid, 18.4 μg%; C18:1trans, elaidic acid, 3.5 μg%; C18:2, linoleic acid, 10.1 μg% produce anxiolytic-like effects that are comparable to diazepam in Wistar rats, suggesting the involvement of γ-aminobutyric acid-A (GABAA receptors, a possibility not yet explored. Wistar rats were subjected to the defensive burying test, elevated plus maze, and open field test. In different groups, three GABAA receptor antagonists were administered 30 min before FAT-M administration, including the competitive GABA binding antagonist bicuculline (1 mg/kg, GABAA benzodiazepine antagonist flumazenil (5 mg/kg, and noncompetitive GABAA chloride channel antagonist picrotoxin (1 mg/kg. The FAT-M exerted anxiolytic-like effects in the defensive burying test and elevated plus maze, without affecting locomotor activity in the open field test. The GABAA antagonists alone did not produce significant changes in the behavioral tests. Picrotoxin but not bicuculline or flumazenil blocked the anxiolytic-like effect of the FAT-M. Based on the specific blocking action of picrotoxin on the effects of the FAT-M, we conclude that the FAT-M exerted its anxiolytic-like effects through GABAA receptor chloride channels.

  1. Inhibitors of swelling-activated chloride channels increase infarct size and apoptosis in rabbit myocardium.

    Science.gov (United States)

    Souktani, Rachid; Ghaleh, Bijan; Tissier, Renaud; d'Anglemont de Tassigny, Alexandra; Aouam, Karim; Bedossa, Pierre; Charlemagne, Danièle; Samuel, Janelyse; Henry, Patrick; Berdeaux, Alain

    2003-10-01

    Apoptosis is a significant contributor to myocardial cell death during ischemia-reperfusion and swelling-activated chloride channels (I(Cl,swell)) contribute to apoptosis. However, the relationship between I(Cl,swell) ischemia-reperfusion and apoptosis remains unknown. To further investigate this, New Zealand rabbits underwent a 20-min coronary artery occlusion (CAO) followed by 72 h of coronary artery reperfusion (CAR). Two I(Cl,swell) blockers, 5-nitro-2-[3-phenylpropylamino]benzoic acid (NPPB) and indanyloxyacetic acid 94 (IAA-94) (both 1 mg/kg), were administered prior to CAO and throughout the 72 h CAR. Infarct size (IS) was increased with NPPB and IAA-94 compared with control (vehicle) rabbits (51 +/- 2% and 48 +/- 3% and vs. 35 +/- 2%, respectively, P < 0.05). Similar results were found when NPPB was administered only during the reperfusion period. The percentage of TUNEL-positive nuclei in the border zone of the infarct was increased with NPPB compared with control (37 +/- 2% vs. 25 +/- 31%, P < 0.05) as well as the number of cytoplasmic histone-associated DNA fragments (0.45 +/- 0.06 vs. 0.33 +/- 0.04 absorbance units, P < 0.05). These findings support the concept that I(Cl,swell) channels play an important role in the determination of myocardial infarct size and apoptosis during ischemia-reperfusion. PMID:14703716

  2. Molecular dissection of gating in the ClC-2 chloride channel.

    Science.gov (United States)

    Jordt, S E; Jentsch, T J

    1997-04-01

    The ClC-2 chloride channel is probably involved in the regulation of cell volume and of neuronal excitability. Site-directed mutagenesis was used to understand ClC-2 activation in response to cell swelling, hyperpolarization and acidic extracellular pH. Similar to equivalent mutations in ClC-0, neutralizing Lys566 at the end of the transmembrane domains results in outward rectification and a shift in voltage dependence, but leaves the basic gating mechanism, including swelling activation, intact. In contrast, mutations in the cytoplasmic loop between transmembrane domains D7 and D8 abolish all three modes of activation by constitutively opening the channel without changing its pore properties. These effects resemble those observed with deletions of an amino-terminal inactivation domain, and suggest that it may act as its receptor. Such a 'ball-and-chain' type mechanism may act as a final pathway in the activation of ClC-2 elicited by several stimuli. PMID:9130703

  3. Interaction of Human Chloride Intracellular Channel Protein 1 (CLIC1) with Lipid Bilayers: A Fluorescence Study.

    Science.gov (United States)

    Hare, Joanna E; Goodchild, Sophia C; Breit, Samuel N; Curmi, Paul M G; Brown, Louise J

    2016-07-12

    Chloride intracellular channel protein 1 (CLIC1) is very unusual as it adopts a soluble glutathione S-transferase-like canonical fold but can also autoinsert into lipid bilayers to form an ion channel. The conversion between these forms involves a large, but reversible, structural rearrangement of the CLIC1 module. The only identified environmental triggers controlling the metamorphic transition of CLIC1 are pH and oxidation. Until now, there have been no high-resolution structural data available for the CLIC1 integral membrane state, and consequently, a limited understanding of how CLIC1 unfolds and refolds across the bilayer to form a membrane protein with ion channel activity exists. Here we show that fluorescence spectroscopy can be used to establish the interaction and position of CLIC1 in a lipid bilayer. Our method employs a fluorescence energy transfer (FRET) approach between CLIC1 and a dansyl-labeled lipid analogue to probe the CLIC1-lipid interface. Under oxidizing conditions, a strong FRET signal between the single tryptophan residue of CLIC1 (Trp35) and the dansyl-lipid analogue was detected. When considering the proportion of CLIC1 interacting with the lipid bilayer, as estimated by fluorescence quenching experiments, the FRET distance between Trp35 and the dansyl moiety on the membrane surface was determined to be ∼15 Å. This FRET-detected interaction provides direct structural evidence that CLIC1 associates with membranes. The results presented support the current model of an oxidation-driven interaction of CLIC1 with lipid bilayers and also propose a membrane anchoring role for Trp35. PMID:27299171

  4. Functional evaluation of human ClC-2 chloride channel mutations associated with idiopathic generalized epilepsies.

    Science.gov (United States)

    Niemeyer, María Isabel; Yusef, Yamil R; Cornejo, Isabel; Flores, Carlos A; Sepúlveda, Francisco V; Cid, L Pablo

    2004-09-16

    The ClC-2 Cl- channel has been postulated to play a role in the inhibitory GABA response in neurons or to participate in astrocyte-dependent extracellular electrolyte homeostasis. Three different mutations in the CLCN2 gene, encoding the voltage-dependent homodimeric ClC-2 channel, have been associated with idiopathic generalized epilepsy (IGE). We study their function in vitro by patch clamp and confocal microscopy in transiently transfected HEK-293 cells. A first mutation predicts a premature stop codon (M200fsX231). An altered splicing, due to an 11-bp deletion in intron 2 (IVS2-14del11), predicts exon 3 skipping (Delta74-117). A third is a missense mutation (G715E). M200fsX231 and Delta74-117 are nonfunctional and do not affect the function of the normal (wild type, WT) channel. Neither M200fsX231 nor Delta74-117 reach the plasma membrane. Concerning the IVS2-14del11 mutation, we find no difference in the proportion of exon-skipped to normally spliced mRNA using a minigene approach and, on this basis, predict no alteration in channel expression in affected individuals. G715E has voltage dependence and intracellular Cl- dependence indistinguishable from WT channels. ClC-2 channels are shown to be sensitive to intracellular replacement of ATP by AMP, which accelerates the opening and closing kinetics. This effect is diminished in the G715E mutant and not significant in WT+G715E coexpression. We do not know whether, in a situation of cellular ATP depletion, this might become pathological in individuals carrying the mutation. We postulate that loss of function mutation M200fsX231 of ClC-2 might contribute to the IGE phenotype through a haploinsufficiency mechanism. PMID:15252188

  5. Expression, purification, crystallization and preliminary X-ray diffraction analysis of chloride intracellular channel 2 (CLIC2)

    International Nuclear Information System (INIS)

    Chloride intracellular channel 2 (CLIC2) belongs to a family of intracellular chloride-channel proteins that can exist in a soluble form. The expression, purification and crystallization in two different crystal forms of human CLIC2 is reported. The chloride intracellular channel (CLIC) family of proteins are unusual in that they can exist in either an integral membrane-channel form or a soluble form. Here, the expression, purification, crystallization and preliminary diffraction analysis of CLIC2, one of the least-studied members of this family, are reported. Human CLIC2 was crystallized in two different forms, both in the presence of reduced glutathione and both of which diffracted to better than 1.9 Å resolution. Crystal form A displayed P212121 symmetry, with unit-cell parameters a = 44.0, b = 74.7, c = 79.8 Å. Crystal form B displayed P21 symmetry, with unit-cell parameters a = 36.0, b = 66.9, c = 44.1 Å. Structure determination will shed more light on the structure and function of this enigmatic family of proteins

  6. Inhibition of the voltage-dependent chloride channel of Torpedo electric organ by diisopropylfluorophosphate and its reversal by oximes

    International Nuclear Information System (INIS)

    Diisopropylfluorophosphate (DFP), a potent organophosphate inhibitor of cholinesterases, was found to inhibit the specific binding of [35S]t-butylbicyclophosphorothionate (TBPS), specific chloride channels ligand, to the electric organ membranes of Torpedo, with a Ki of 21 +/- 3 μM. The binding sites of [35S]TBPS in the Torpedo membranes were found not to be GABA receptors or nicotinic acetylcholine receptors as previously described. Interestingly, a stimulation of the binding of [35S]TBPS was observed in the presence of atropine and three oximes, monopyridinium oxime 2-PAM, bispyridinium bis-oxime TMB-4 and H-oxime HI-6. The maximal stimulation was 300-500% of control, after which, the stimulation was reversed at higher concentrations. The three oximes protected by more than 95% the inhibition by 1 mM DFP of the binding of [35S]TBPS to the voltage-dependent chloride channel. However, atropine protected only 20% of the inhibited channel. These results, thus, suggest that the protection against the toxic effects of DFP or other anticholinesterase agents by the tested oximes may not be solely a result of the reactivation of cholinesterases but also the protection of the voltage-dependent chloride channel

  7. Regulation of CLC-1 chloride channel biosynthesis by FKBP8 and Hsp90β

    Science.gov (United States)

    Peng, Yi-Jheng; Huang, Jing-Jia; Wu, Hao-Han; Hsieh, Hsin-Ying; Wu, Chia-Ying; Chen, Shu-Ching; Chen, Tsung-Yu; Tang, Chih-Yung

    2016-01-01

    Mutations in human CLC-1 chloride channel are associated with the skeletal muscle disorder myotonia congenita. The disease-causing mutant A531V manifests enhanced proteasomal degradation of CLC-1. We recently found that CLC-1 degradation is mediated by cullin 4 ubiquitin ligase complex. It is currently unclear how quality control and protein degradation systems coordinate with each other to process the biosynthesis of CLC-1. Herein we aim to ascertain the molecular nature of the protein quality control system for CLC-1. We identified three CLC-1-interacting proteins that are well-known heat shock protein 90 (Hsp90)-associated co-chaperones: FK506-binding protein 8 (FKBP8), activator of Hsp90 ATPase homolog 1 (Aha1), and Hsp70/Hsp90 organizing protein (HOP). These co-chaperones promote both the protein level and the functional expression of CLC-1 wild-type and A531V mutant. CLC-1 biosynthesis is also facilitated by the molecular chaperones Hsc70 and Hsp90β. The protein stability of CLC-1 is notably increased by FKBP8 and the Hsp90β inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) that substantially suppresses cullin 4 expression. We further confirmed that cullin 4 may interact with Hsp90β and FKBP8. Our data are consistent with the idea that FKBP8 and Hsp90β play an essential role in the late phase of CLC-1 quality control by dynamically coordinating protein folding and degradation. PMID:27580824

  8. Mapping convulsants’ binding to the GABA-A receptor chloride ionophore: a proposed model for channel binding sites

    OpenAIRE

    Kalueff, A.V.

    2006-01-01

    Gamma aminobutyric acid (GABA) type A receptors play a key role in brain inhibitory neurotransmission, and are ligand-activated chloride channels blocked by numerous convulsant ligands. Here we summarize data on binding of picrotoxin, tetrazoles, β-lactams, bicyclophosphates, butyrolactones and neurotoxic pesticides to GABA-A ionophore, and discuss functional and structural overlapping of their binding sites. The paper reviews data on convulsants’ binding sensitivity to different point mutati...

  9. Spectrum of mutations in the major human skeletal muscle chloride channel gene (CLCN1) leading to myotonia.

    OpenAIRE

    Meyer-Kleine, C; Steinmeyer, K; Ricker, K; Jentsch, T J; Koch, M C

    1995-01-01

    Autosomal dominant myotonia congenita and autosomal recessive generalized myotonia (GM) are genetic disorders characterized by the symptom of myotonia, which is based on an electrical instability of the muscle fiber membrane. Recently, these two phenotypes have been associated with mutations in the major muscle chloride channel gene CLCN1 on human chromosome 7q35. We have systematically screened the open reading frame of the CLCN1 gene for mutations by SSC analysis (SSCA) in a panel of 24 fam...

  10. Coupled-channels extension of the closed formalism for heavy-ion collisions

    International Nuclear Information System (INIS)

    An extension of the closed formalism for elastic and quasielastic heavy-ion collisions to account for channel coupling effects on these processes is presented. Starting from coupled-channels equations, are used suitable approximations to calculate directly the corrections to the elastic partial-wave S-matrix that arise from the feedback of certain strongly coupled channels on elastic scattering, without having to determine effective potentials as an intermediate step. The S-matrix corrections are completely determined by the characteristics of the transitions to the intermediary channels (spectroscopic and form factors) and by the uncoupled elastic S-matrix. The corresponding contributions to the scattering amplitude are evaluated in closed form. As examples, explicit expressions for coupling to inelastic collective channels are derived, by both Coulomb and nuclear excitation, and to transfer reaction channels. (Author)

  11. Closed-Form Expressions for Secrecy Capacity over Correlated Rayleigh Fading Channels

    CERN Document Server

    Sun, Xiaojun; Jiang, Ming

    2010-01-01

    We investigate the secure communications over correlated wiretap Rayleigh fading channels assuming the full channel state information (CSI) available. Based on the information theoretic formulation, we derive closed-form expressions for the average secrecy capacity and the outage probability. Simulation results confirm our analytical expressions.

  12. Unusual systemic venous Collateral channels to left atrium causing desaturation after Fontan operation closed percutaneously

    Directory of Open Access Journals (Sweden)

    Ashutosh Marwah

    2013-01-01

    Full Text Available We present an unusual cause of progressive cyanosis in a child appearing 2 years after successful Fontan surgery for tetralogy of Fallot with hypoplastic right ventricle. The cause of cyanosis was identified as one large venous channel draining into the left atrium. The channel was closed by Amplatzer vascular plug resulting in improvement of oxygen saturation.

  13. Cytoplasmic pathway followed by chloride ions to enter the CFTR channel pore.

    Science.gov (United States)

    El Hiani, Yassine; Negoda, Alexander; Linsdell, Paul

    2016-05-01

    Most ATP-binding cassette (ABC) proteins function as ATP-dependent membrane pumps. One exception is the cystic fibrosis transmembrane conductance regulator (CFTR), an ABC protein that functions as a Cl(-) ion channel. As such, the CFTR protein must form a continuous pathway for the movement of Cl(-) ions from the cytoplasm to the extracellular solution when in its open channel state. Extensive functional investigations have characterized most parts of this Cl(-) permeation pathway. However, one region remains unexplored-the pathway connecting the cytoplasm to the membrane-spanning pore. We used patch clamp recording and extensive substituted cysteine accessibility mutagenesis to identify amino acid side-chains in cytoplasmic regions of CFTR that lie close to the pathway taken by Cl(-) ions as they pass from the cytoplasm through this pathway. Our results suggest that Cl(-) ions enter the permeation pathway via a single lateral tunnel formed by the cytoplasmic parts of the protein, and then follow a fairly direct central pathway towards the membrane-spanning parts of the protein. However, this pathway is not lined continuously by any particular part of the protein; instead, the contributions of different cytoplasmic regions of the protein appear to change as the permeation pathway approaches the membrane, which appears to reflect the ways in which different cytoplasmic regions of the protein are oriented towards its central axis. Our results allow us to define for the first time the complete Cl(-) permeation pathway in CFTR, from the cytoplasm to the extracellular solution. PMID:26659082

  14. Silent S-Type Anion Channel Subunit SLAH1 Gates SLAH3 Open for Chloride Root-to-Shoot Translocation.

    Science.gov (United States)

    Cubero-Font, Paloma; Maierhofer, Tobias; Jaslan, Justyna; Rosales, Miguel A; Espartero, Joaquín; Díaz-Rueda, Pablo; Müller, Heike M; Hürter, Anna-Lena; Al-Rasheid, Khaled A S; Marten, Irene; Hedrich, Rainer; Colmenero-Flores, José M; Geiger, Dietmar

    2016-08-22

    Higher plants take up nutrients via the roots and load them into xylem vessels for translocation to the shoot. After uptake, anions have to be channeled toward the root xylem vessels. Thereby, xylem parenchyma and pericycle cells control the anion composition of the root-shoot xylem sap [1-6]. The fact that salt-tolerant genotypes possess lower xylem-sap Cl(-) contents compared to salt-sensitive genotypes [7-10] indicates that membrane transport proteins at the sites of xylem loading contribute to plant salinity tolerance via selective chloride exclusion. However, the molecular mechanism of xylem loading that lies behind the balance between NO3(-) and Cl(-) loading remains largely unknown. Here we identify two root anion channels in Arabidopsis, SLAH1 and SLAH3, that control the shoot NO3(-)/Cl(-) ratio. The AtSLAH1 gene is expressed in the root xylem-pole pericycle, where it co-localizes with AtSLAH3. Under high soil salinity, AtSLAH1 expression markedly declined and the chloride content of the xylem sap in AtSLAH1 loss-of-function mutants was half of the wild-type level only. SLAH3 anion channels are not active per se but require extracellular nitrate and phosphorylation by calcium-dependent kinases (CPKs) [11-13]. When co-expressed in Xenopus oocytes, however, the electrically silent SLAH1 subunit gates SLAH3 open even in the absence of nitrate- and calcium-dependent kinases. Apparently, SLAH1/SLAH3 heteromerization facilitates SLAH3-mediated chloride efflux from pericycle cells into the root xylem vessels. Our results indicate that under salt stress, plants adjust the distribution of NO3(-) and Cl(-) between root and shoot via differential expression and assembly of SLAH1/SLAH3 anion channel subunits. PMID:27397895

  15. Protein kinase C-mediated phosphorylation of the human multidrug resistance P-glycoprotein regulates cell volume-activated chloride channels.

    OpenAIRE

    Hardy, S P; Goodfellow, H R; Valverde, M. A. (Miguel ??ngel), 1963-; Gill, D. R.; Sepúlveda, V; Higgins, C F

    1995-01-01

    The multidrug resistance P-glycoprotein (P-gp), which transports hydrophobic drugs out of cells, is also associated with volume-activated chloride currents. It is not yet clear whether P-gp is a channel itself, or whether it is a channel regulator. Activation of chloride currents by hypotonicity in cells expressing P-gp was shown to be regulated by protein kinase C (PKC). HeLa cells exhibited volume-activated chloride currents indistinguishable from those obtained in P-gp-expressing cells exc...

  16. Fluid shear stress enhances the cell volume decrease of osteoblast cells by increasing the expression of the ClC-3 chloride channel

    OpenAIRE

    Liu, Li; Cai, Siyi; Qiu, Guixing; Lin, Jin

    2016-01-01

    ClC-3 is a volume-sensitive chloride channel that is responsible for cell volume adjustment and regulatory cell volume decrease (RVD). In order to evaluate the effects of fluid shear stress (FSS) stimulation on the osteoblast ClC-3 chloride channel, MC3T3-E1 cells were stimulated by FSS in the experimental group. Fluorescence quantitative polymerase chain reaction was used to detect changes in ClC-3 mRNA expression, the chloride ion fluorescent probe N-(ethoxycarbonylmethyl)-6-methoxyquinolin...

  17. Interaction of the chloride intracellular ion channel protein CLIC1 with different sterols in model membranes

    International Nuclear Information System (INIS)

    Background and Aims: Sterols have been reported to modulate conformation and hence the function of several membrane proteins. One such group is the Chloride Intracellular Ion Channel (CLIC) family of proteins. The CLIC protein family consists of six evolutionarily conserved protein members in vertebrates. These proteins are unusual, existing as both monomeric soluble proteins and as membrane bound proteins. We now for the first time demonstrate that the spontaneous membrane insertion of CLIC1 is dependent on the presence of cholesterol in membranes. Our novel findings also extend to the identification of a cholesterol-binding domain within CLIC1 that facilitates the spontaneous membrane insertion of the protein into membranes containing cholesterol. Methods: CLIC1 wild type (WT) and mutant proteins were purified by Ni-NTA followed by size‐exclusion chromatography. Langmuir monolayer film balance experiments were carried out using 1-Palmitoyl-2-oleoylphosphatidylcholine (POPC) alone, or in a 5:1 mole ratio combination with either one of the following sterols: Cholesterol (CHOL), β-Sitosterol (SITO), Ergosterol (ERG), Hydroxyecdysone (HYD) or Cholestane (CHOS). WT CLIC1 or mutant versions of CLIC1 were then injected into the aqueous subphase under the lipid film. Results: In lipid monolayers lacking sterols, CLIC1 did not insert. However significant membrane insertion occurred when CLIC1 was added to membranes containing cholesterol. Substitution of membrane cholesterol with either HYD, SITO or ERG, not only increased CLIC1’s membrane interaction but also increased its rate of insertion. Conversely, CLIC1 showed no insertion into monolayers containing CHOS, which lacked the intact sterol 3β-OH group. CLIC1 mutants G18A and G22A, did not insert in POPC:CHOL monolayers whereas the C24A mutant showed membrane insertion equivalent to WT CLIC1. X-ray and Neutron reflectivity, along with Small Angle X-ray Scattering techniques were subsequently used to probe

  18. The chloride-channel blocker 9-anthracenecarboxylic acid reduces the nonlinear capacitance of prestin-associated charge movement.

    Science.gov (United States)

    Harasztosi, Csaba; Gummer, Anthony W

    2016-04-01

    The basis of the extraordinary sensitivity and frequency selectivity of the cochlea is a chloride-sensitive protein called prestin which can produce an electromechanical response and which resides in the basolateral plasma membrane of outer hair cells (OHCs). The compound 9-anthracenecarboxylic acid (9-AC), an inhibitor of chloride channels, has been found to reduce the electromechanical response of the cochlea and the OHC mechanical impedance. To elucidate these 9-AC effects, the functional electromechanical status of prestin was assayed by measuring the nonlinear capacitance of OHCs from the guinea-pig cochlea and of prestin-transfected human embryonic kidney 293 (HEK 293) cells. Extracellular application of 9-AC caused reversible, dose-dependent and chloride-sensitive reduction in OHC nonlinear charge transfer, Qmax . Prestin-transfected cells also showed reversible reduction in Qmax . For OHCs, intracellular 9-AC application as well as reduced intracellular pH had no detectable effect on the reduction in Qmax by extracellularly applied 9-AC. In the prestin-transfected cells, cytosolic application of 9-AC approximately halved the blocking efficacy of extracellularly applied 9-AC. OHC inside-out patches presented the whole-cell blocking characteristics. Disruption of the cytoskeleton by preventing actin polymerization with latrunculin A or by decoupling of spectrin from actin with diamide did not affect the 9-AC-evoked reduction in Qmax . We conclude that 9-AC acts on the electromechanical transducer principally by interaction with prestin rather than acting via the cytoskeleton, chloride channels or pH. The 9-AC block presents characteristics in common with salicylate, but is almost an order of magnitude faster. 9-AC provides a new tool for elucidating the molecular dynamics of prestin function. PMID:26869218

  19. High glucose inhibits ClC-2 chloride channels and attenuates cell migration of rat keratinocytes

    Directory of Open Access Journals (Sweden)

    Pan F

    2015-08-01

    Full Text Available Fuqiang Pan, Rui Guo, Wenguang Cheng, Linlin Chai, Wenping Wang, Chuan Cao, Shirong LiDepartment of Plastic and Reconstructive Surgery, Southwestern Hospital, Third Military Medical University, Chongqing, People’s Republic of China Background: Accumulating evidence has demonstrated that migration of keratinocytes is critical to wound epithelialization, and defects of this function result in chronic delayed-healing wounds in diabetes mellitus patients, and the migration has been proved to be associated with volume-activated chloride channels. The aim of the study is to investigate the effects of high glucose (HG, 25 mM on ClC-2 chloride channels and cell migration of keratinocytes.Methods: Newborn Sprague Dawley rats were used to isolate and culture the keratinocyte in this study. Immunofluorescence assay, real-time polymerase chain reaction, and Western blot assay were used to examine the expression of ClC-2 protein or mRNA. Scratch wound assay was used to measure the migratory ability of keratinocytes. Transwell cell migration assay was used to measure the invasion and migration of keratinocytes. Recombinant lentivirus vectors were established and transducted to keratinocytes. Whole-cell patch clamp was used to perform the electrophysiological studies.Results: We found that the expression of ClC-2 was significantly inhibited when keratinocytes were exposed to a HG (25 mM medium, accompanied by the decline of volume-activated Cl- current (ICl,vol, migration potential, and phosphorylated PI3K as compared to control group. When knockdown of ClC-2 by RNAi or pretreatment with wortmannin, similar results were observed, including ICl,vol and migration keratinocytes were inhibited.Conclusion: Our study proved that HG inhibited ClC-2 chloride channels and attenuated cell migration of rat keratinocytes via inhibiting PI3K signaling.Keywords: high glucose, keratinocytes, ClC-2, cell migration, PI3K

  20. Molecular determinants of anion selectivity in the cystic fibrosis transmembrane conductance regulator chloride channel pore.

    OpenAIRE

    Linsdell, P; Evagelidis, A; Hanrahan, J W

    2000-01-01

    Ionic selectivity in many cation channels is achieved over a short region of the pore known as the selectivity filter, the molecular determinants of which have been identified in Ca(2+), Na(+), and K(+) channels. However, a filter controlling selectivity among different anions has not previously been identified in any Cl(-) channel. In fact, because Cl(-) channels are only weakly selective among small anions, and because their selectivity has proved so resistant to site-directed mutagenesis, ...

  1. Characterization of the putative chloride channel xClC-5 expressed in Xenopus laevis oocytes and comparison with endogenous chloride currents.

    Science.gov (United States)

    Schmieder, S; Lindenthal, S; Banderali, U; Ehrenfeld, J

    1998-09-01

    1. We recently cloned a putative chloride channel (xClC-5) from the renal cell line A6, which induced the appearance of a Cl- conductance not found in control oocytes after homologous expression in Xenopus oocytes. With the aim of increasing the Xenopus oocyte xClC-5 expression, we constructed a new plasmid in which the native 5' and 3' non-coding regions of xClC-5 were replaced by the non-coding regions of the Xenopus beta-globin sequence and in which a Kozak consensus site was introduced before the initiator ATG. 2. We then compared the induced currents Inative (induced by injection of cRNA presenting the native non-coding regions of xClC-5) and Ibeta-globin (induced by injection of cRNA presenting the non-coding regions of the Xenopus beta-globin sequence) investigating anion selectivity and anion blocker sensitivity. Several differences were found: (1) expression yield and oocyte surviving rate were largely increased by injecting (beta) xClC-5 cRNA, (2) the Ibeta-globin outward rectification score was 2.6 times that of Inative, (3) the anion conductivity sequence was nitrate > bromide > chloride > iodide > gluconate for Ibeta-globin and iodide > bromide > nitrate > chloride > gluconate for Inative, (4) 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), anthracene-9-carboxylic acid (9-AC), DIDS, lanthanum ions, cAMP and ionomycin-induced [Ca2+]i increase inhibited Inative but had no effect on Ibeta-globin, and (5) Inative showed considerable similarity to the previously reported endogenous current appearing after ClC-6 or pICln cRNA injection. 3. Comparison of Inative with the endogenous chloride current ICl,swell which develops under hyposmotic conditions demonstrated several similarities in their electrophysiological and pharmacological characteristics but were nevertheless distinguishable. 4. In vitro translation assays demonstrated that protein synthesis was much greater using the (beta) xClC-5 construct than that of xClC-5. Furthermore, immunoreactivity

  2. Calcium-activated chloride channel ANO1 promotes breast cancer progression by activating EGFR and CAMK signaling

    OpenAIRE

    Britschgi, Adrian; Bill, Anke; Brinkhaus, Heike; Rothwell, Christopher; Clay, Ieuan; Duss, Stephan; Rebhan, Michael; Raman, Pichai; Guy, Chantale T.; Wetzel, Kristie; George, Elizabeth; Popa, M. Oana; Lilley, Sarah; Choudhury, Hedaythul; Gosling, Martin

    2013-01-01

    The calcium-activated chloride channel anoctamin 1 (ANO1) is located within the 11q13 amplicon, one of the most frequently amplified chromosomal regions in human cancer, but its functional role in tumorigenesis has remained unclear. The 11q13 region is amplified in ∼15% of breast cancers. Whether ANO1 is amplified in breast tumors, the extent to which gene amplification contributes to ANO1 overexpression, and whether overexpression of ANO1 is important for tumor maintenance have remained unkn...

  3. Closed Form Secrecy Capacity of MIMO Wiretap Channels with Two Transmit Antennas

    CERN Document Server

    Li, Jiangyuan

    2011-01-01

    A Gaussian multiple-input multiple-output (MIMO) wiretap channel model is considered. The input is a two-antenna transmitter, while the outputs are the legitimate receiver and an eavesdropper, both equipped with multiple antennas. All channels are assumed to be known. The problem of obtaining the optimal input covariance matrix that achieves secrecy capacity subject to a power constraint is addressed, and a closed-form expression for the secrecy capacity is obtained.

  4. Expression and Function of CLC and Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channels in Renal Epithelial Tubule Cells: Pathophysiological Implications

    Directory of Open Access Journals (Sweden)

    Alain Vandewalle

    2007-02-01

    Full Text Available Cl- channels play important roles in the regulation of a variety of functions, includingelectrical excitability, cell volume regulation, transepithelial transport and acidification ofcellular organelles. They are expressed in plasma membranes or reside in intracellularorganelles. A large number of Cl- channels with different functions have been identified.Some of them are highly expressed in the kidney. They include members of the CLC Clchannelfamily: ClC-K1 (or ClC-Ka, ClC-K2 (or ClC-Kb and ClC-5. The identification ofmutations responsible for human inherited diseases (Bartter syndrome for ClC-Kb andDent’s disease for ClC-5 and studies on knockout mice models have evidenced the physiologicalimportance of these CLC Cl- channels, permitting better understanding on their functionsin renal tubule epithelial cells. The cystic fibrosis transmembrane conductance regulator(CFTR Cl- channel, also expressed in renal tubule epithelial cells, is involved in thetransepithelial transport of Cl- in the distal nephron. This short review focuses on intrarenaldistribution, subcellular localization and function of the ClK-1, ClC-K2 and ClC-5 Cl- channelsin renal tubule epithelial cells, and the role of the CFTR Cl- channel in chloride fluxeselicited by vasopressin in the distal nephron.

  5. Regulation of the membrane insertion and conductance activity of the metamorphic chloride intracellular channel protein CLIC1 by cholesterol.

    Directory of Open Access Journals (Sweden)

    Stella M Valenzuela

    Full Text Available The Chloride Intracellular ion channel protein CLIC1 has the ability to spontaneously insert into lipid membranes from a soluble, globular state. The precise mechanism of how this occurs and what regulates this insertion is still largely unknown, although factors such as pH and redox environment are known contributors. In the current study, we demonstrate that the presence and concentration of cholesterol in the membrane regulates the spontaneous insertion of CLIC1 into the membrane as well as its ion channel activity. The study employed pressure versus area change measurements of Langmuir lipid monolayer films; and impedance spectroscopy measurements using tethered bilayer membranes to monitor membrane conductance during and following the addition of CLIC1 protein. The observed cholesterol dependent behaviour of CLIC1 is highly reminiscent of the cholesterol-dependent-cytolysin family of bacterial pore-forming proteins, suggesting common regulatory mechanisms for spontaneous protein insertion into the membrane bilayer.

  6. Blockade of chloride channels by DIDS stimulates renin release and inhibits contraction of afferent arterioles

    DEFF Research Database (Denmark)

    Jensen, B L; Skøtt, O

    without ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] and DIDS were not additive. In the absence of chloride, basal renin release was suppressed and the stimulatory effect of DIDS was abolished. The DIDS-induced enhancement of renin release was not dependent on bicarbonate...

  7. Pricing Decisions of a Dual-Channel Closed-Loop Supply Chain under Uncertain Demand of Indirect Channel

    Directory of Open Access Journals (Sweden)

    Jie Gao

    2016-01-01

    Full Text Available The dual-channel closed-loop supply chain (CLSC which is composed of one manufacturer and one retailer under uncertain demand of an indirect channel is constructed. In this paper, we establish three pricing models under decentralized decision making, namely, the Nash game between the manufacturer and the retailer, the manufacturer-Stackelberg game, and the retailer-Stackelberg game, to investigate pricing decisions of the CLSC in which the manufacturer uses the direct channel and indirect channel to sell products and entrusts the retailer to collect the used products. We numerically analyze the impact of customer acceptance of the direct channel (θ on pricing decisions and excepted profits of the CLSC. The results show that when the variable θ changes in a certain range, the wholesale price, retail price, and expected profits of the retailer all decrease when θ increases, while the direct online sales price and manufacturer’s expected profits in the retailer-Stackelberg game all increase when θ increases. However, the optimal recycling transfer price and optimal acquisition price of used product are unaffected by θ.

  8. Cell swelling activates separate taurine and chloride channels in Ehrlich mouse ascites tumor cells

    DEFF Research Database (Denmark)

    Lambert, Ian Henry; Hoffmann, Else Kay

    1994-01-01

    The taurine efflux from Ehrlich ascites tumor cells is stimulated by hypotonic cell swelling. The swelling-activated taurine efflux is unaffected by substitution of gluconate for extracellular Cl– but inhibited by addition of MK196 (anion channel blocker) and 4,4 -diisothiocyanostilbene-2......,2 -disulfonic acid (DIDS; anion channel and anion exchange blocker) and by depolarization of the cell membrane. This is taken to indicate that taurine does not leave the osmotically swollen Ehrlich cells in exchange for extracellular Cl–, i.e., via the anion exchanger but via a MK196- and DIDS-sensitive channel...... that is potential dependent. An additional stimulation of the swelling-activated taurine efflux is seen after addition of arachidonic acid and oleic acid. Cell swelling also activates a Mini Cl– channel. The Cl– efflux via this Cl– channel, in contrast to the swelling-activated taurine efflux, is...

  9. PERFORMANCE OF CLOSED LOOP TRANSMIT DIVERSITY IN A RAYLEIGH FADING CHANNEL

    Institute of Scientific and Technical Information of China (English)

    Yang Xin; You Xiaohu

    2006-01-01

    In this paper, the closed loop transmit diversity technology for the Wideband Code Division Multiple Access(WCDMA) systems is investigated in a multipath Rayleigh fading channel. The RAKE receiver model and the weighing vector algorithm are presented. The performance is theoretically analyzed in terms of the average maximal Signal-to-Noise Ratio(SNR) gain available over the Space-Time block coding based Transmit Diversity(STTD) technology. Theoretic analysis and simulation results show that the closed loop transmit diversity can provide a 3dB performance gain over the open loop scheme in a single path fading channel, while the performance gain decreases dramatically with the increasing inherent multipath diversity of the wireless channel.

  10. Changes in cationic selectivity of the nicotinic channel at the rat ganglionic synapse: a role for chloride ions?

    Directory of Open Access Journals (Sweden)

    Oscar Sacchi

    Full Text Available The permeability of the nicotinic channel (nAChR at the ganglionic synapse has been examined, in the intact rat superior cervical ganglion in vitro, by fitting the Goldman current equation to the synaptic current (EPSC I-V relationship. Subsynaptic nAChRs, activated by neurally-released acetylcholine (ACh, were thus analyzed in an intact environment as natively expressed by the mature sympathetic neuron. Postsynaptic neuron hyperpolarization (from -40 to -90 mV resulted in a change of the synaptic potassium/sodium permeability ratio (P(K/P(Na from 1.40 to 0.92, corresponding to a reversible shift of the apparent acetylcholine equilibrium potential, E(ACh, by about +10 mV. The effect was accompanied by a decrease of the peak synaptic conductance (g(syn and of the EPSC decay time constant. Reduction of [Cl(-](o to 18 mM resulted in a change of P(K/P(Na from 1.57 (control to 2.26, associated with a reversible shift of E(ACh by about -10 mV. Application of 200 nM αBgTx evoked P(K/P(Na and g(syn modifications similar to those observed in reduced [Cl(-](o. The two treatments were overlapping and complementary, as if the same site/mechanism were involved. The difference current before and after chloride reduction or toxin application exhibited a strongly positive equilibrium potential, which could not be explained by the block of a calcium component of the EPSC. Observations under current-clamp conditions suggest that the driving force modification of the EPSC due to P(K/P(Na changes represent an additional powerful integrative mechanism of neuron behavior. A possible role for chloride ions is suggested: the nAChR selectivity was actually reduced by increased chloride gradient (membrane hyperpolarization, while it was increased, moving towards a channel preferentially permeable for potassium, when the chloride gradient was reduced.

  11. Performance Evaluation of Closed-Loop Spatial Multiplexing Codebook Based on Indoor MIMO Channel Measurement

    Directory of Open Access Journals (Sweden)

    Junjun Gao

    2012-01-01

    Full Text Available Closed-loop MIMO technique standardized in LTE can support different layer transmissions through precoding operation to match the channel multiplexing capability. However, the performance of the limited size codebook still needs to be evaluated in real channel environment for further insights. Based on the wideband MIMO channel measurement in a typical indoor scenario, capacity loss (CL of the limited size codebook relative to perfect precoding is studied first in two extreme channel conditions. The results show that current codebook design for single layer transmission is nearly capacity lossless, and the CL will increase with the number of transmitted layers. Furthermore, the capacity improvement of better codebook selection criterions is very limited compared to CL. Then we define the maximum capacity boost achieved by frequency domain layer adaption (FDLA and investigate its sensitivity to SNR and channel condition. To survey the effect of frequency domain channel variation on MIMO-OFDM system, we define a function to measure the fluctuation levels of the key channel metrics within a subband and reveal the inherent relationship between them. Finally, a capacity floor resulted as the feedback interval increases in frequency domain.

  12. Endogenous chloride channels of insect sf9 cells. Evidence for coordinated activity of small elementary channel units

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Gabriel, S. E.; Stutts, M. J.;

    1996-01-01

    The endogenous Cl- conductance of Spodoptera frugiperda (Sf9) cells was studied 20-35 h after plating out of either uninfected cells or cells infected by a baculovirus vector carrying the cloned beta-galactosidase gene (beta-Gal cells). With the cation Tris+ in the pipette and Na+ in the bath....../150) of approximately 3.5 pS and approximately 35 pS, respectively. All states reversed near the same membrane potential, and they exhibited similar halide ion selectivity, P1 > PCl approximately PBr. Accordingly, Cl- current amplitudes larger than current flow through the smallest channel unit resolved seem to result...... from simultaneous open/shut events of two or more channel units....

  13. A family of acetylcholine-gated chloride channel subunits in Caenorhabditis elegans.

    Science.gov (United States)

    Putrenko, Igor; Zakikhani, Mahvash; Dent, Joseph A

    2005-02-25

    The genome of the nematode Caenorhabditis elegans encodes a surprisingly large and diverse superfamily of genes encoding Cys loop ligand-gated ion channels. Here we report the first cloning, expression, and pharmacological characterization of members of a family of anion-selective acetylcholine receptor subunits. Two subunits, ACC-1 and ACC-2, form homomeric channels for which acetylcholine and arecoline, but not nicotine, are efficient agonists. These channels are blocked by d-tubocurarine but not by alpha-bungarotoxin. We provide evidence that two additional subunits, ACC-3 and ACC-4, interact with ACC-1 and ACC-2. The acetylcholine-binding domain of these channels appears to have diverged substantially from the acetylcholine-binding domain of nicotinic receptors. PMID:15579462

  14. Isolated-patch recording from liposomes containing functionally reconstituted chloride channels from Torpedo electroplax.

    OpenAIRE

    Tank, D W; Miller, C.; Webb, W W

    1982-01-01

    Small unilamellar vesicles formed from purified phospholids by detergent/dialysis methods may be enlarged to 30-microns diameter by freezing and thawing. Very-high-resistance seals were formed by applying a glass micropipette to the surface of these large liposomes, and single bilayer "patches" of membrane were isolated from the liposome surface while remaining sealed to the micropipette. The exogenous channel-forming peptides gramicidin and alamethicin induced characteristic single-channel f...

  15. Molecular pharmacology of kidney and inner ear CLC-K chloride channels

    Directory of Open Access Journals (Sweden)

    Antonella eGradogna

    2010-10-01

    Full Text Available CLC-K channels belong to the CLC gene family, which comprises both Cl- channels and Cl-/H+ antiporters. They form homodimers which additionally co-assemble with the small protein barttin. In the kidney, they are involved in NaCl reabsorption ; in the inner ear they are important for endolymph production. Mutations in CLC-Kb lead to renal salt loss (Bartter’s syndrome; mutations in barttin lead additionally to deafness. CLC-K channels are interesting potential drug targets. CLC-K channel blockers have potential as alternative diuretics, whereas CLC-K activators could be used for the treatment of patients with Bartter’s syndrome. Several small organic acids inhibit CLC-K channels from the outside by binding to a site in the external vestibule of the ion conducting pore. Benzofuran derivatives with affinities better than 10 µM have been discovered. Niflumic acid (NFA exhibits a complex interaction with CLC-K channels. Below ~ 1 mM, NFA activates CLC-Ka, whereas at higher concentrations NFA inhibits channel activity. The co-planarity of the rings of the NFA molecule is essential for its activating action. Mutagenesis has led to the identification of potential regions of the channel that interact with NFA. CLC-K channels are also modulated by pH and [Ca2+]ext. The inhibition at low pH has been shown to be mediated by a His-residue at the beginning of helix Q, the penultimate transmembrane helix. Two acidic residues from opposite subunits form two symmetrically related intersubunit Ca2+ binding sites, whose occupation increases channel activity.The relatively high affinity CLC-K blockers may already serve as leads for the development of useful drugs. On the other hand, the CLC-K potentiator NFA has a quite low affinity, and, being a non-steroidal anti-inflammatory drug, can be expected to exert significant side effects. More specific and more potent activators will be needed and it will be important to understand the molecular mechanisms that

  16. Conformational heterogeneity in closed and open states of the KcsA potassium channel in lipid bicelles.

    Science.gov (United States)

    Kim, Dorothy M; Dikiy, Igor; Upadhyay, Vikrant; Posson, David J; Eliezer, David; Nimigean, Crina M

    2016-08-01

    The process of ion channel gating-opening and closing-involves local and global structural changes in the channel in response to external stimuli. Conformational changes depend on the energetic landscape that underlies the transition between closed and open states, which plays a key role in ion channel gating. For the prokaryotic, pH-gated potassium channel KcsA, closed and open states have been extensively studied using structural and functional methods, but the dynamics within each of these functional states as well as the transition between them is not as well understood. In this study, we used solution nuclear magnetic resonance (NMR) spectroscopy to investigate the conformational transitions within specific functional states of KcsA. We incorporated KcsA channels into lipid bicelles and stabilized them into a closed state by using either phosphatidylcholine lipids, known to favor the closed channel, or mutations designed to trap the channel shut by disulfide cross-linking. A distinct state, consistent with an open channel, was uncovered by the addition of cardiolipin lipids. Using selective amino acid labeling at locations within the channel that are known to move during gating, we observed at least two different slowly interconverting conformational states for both closed and open channels. The pH dependence of these conformations and the predictable disruptions to this dependence observed in mutant channels with altered pH sensing highlight the importance of conformational heterogeneity for KcsA gating. PMID:27432996

  17. A voltage-dependent chloride channel fine-tunes photosynthesis in plants.

    Science.gov (United States)

    Herdean, Andrei; Teardo, Enrico; Nilsson, Anders K; Pfeil, Bernard E; Johansson, Oskar N; Ünnep, Renáta; Nagy, Gergely; Zsiros, Ottó; Dana, Somnath; Solymosi, Katalin; Garab, Győző; Szabó, Ildikó; Spetea, Cornelia; Lundin, Björn

    2016-01-01

    In natural habitats, plants frequently experience rapid changes in the intensity of sunlight. To cope with these changes and maximize growth, plants adjust photosynthetic light utilization in electron transport and photoprotective mechanisms. This involves a proton motive force (PMF) across the thylakoid membrane, postulated to be affected by unknown anion (Cl(-)) channels. Here we report that a bestrophin-like protein from Arabidopsis thaliana functions as a voltage-dependent Cl(-) channel in electrophysiological experiments. AtVCCN1 localizes to the thylakoid membrane, and fine-tunes PMF by anion influx into the lumen during illumination, adjusting electron transport and the photoprotective mechanisms. The activity of AtVCCN1 accelerates the activation of photoprotective mechanisms on sudden shifts to high light. Our results reveal that AtVCCN1, a member of a conserved anion channel family, acts as an early component in the rapid adjustment of photosynthesis in variable light environments. PMID:27216227

  18. Expression of calcium-activated chloride channels Ano1 and Ano2 in mouse taste cells.

    Science.gov (United States)

    Cherkashin, Alexander P; Kolesnikova, Alisa S; Tarasov, Michail V; Romanov, Roman A; Rogachevskaja, Olga A; Bystrova, Marina F; Kolesnikov, Stanislav S

    2016-02-01

    Specialized Ca(2+)-dependent ion channels ubiquitously couple intracellular Ca(2+) signals to a change in cell polarization. The existing physiological evidence suggests that Ca(2+)-activated Cl(-) channels (CaCCs) are functional in taste cells. Because Ano1 and Ano2 encode channel proteins that form CaCCs in a variety of cells, we analyzed their expression in mouse taste cells. Transcripts for Ano1 and Ano2 were detected in circumvallate (CV) papillae, and their expression in taste cells was confirmed using immunohistochemistry. When dialyzed with CsCl, taste cells of the type III exhibited no ion currents dependent on cytosolic Ca(2+). Large Ca(2+)-gated currents mediated by TRPM5 were elicited in type II cells by Ca(2+) uncaging. When TRPM5 was inhibited by triphenylphosphine oxide (TPPO), ionomycin stimulated a small but resolvable inward current that was eliminated by anion channel blockers, including T16Ainh-A01 (T16), a specific Ano1 antagonist. This suggests that CaCCs, including Ano1-like channels, are functional in type II cells. In type I cells, CaCCs were prominently active, blockable with the CaCC antagonist CaCCinh-A01 but insensitive to T16. By profiling Ano1 and Ano2 expressions in individual taste cells, we revealed Ano1 transcripts in type II cells only, while Ano2 transcripts were detected in both type I and type II cells. P2Y agonists stimulated Ca(2+)-gated Cl(-) currents in type I cells. Thus, CaCCs, possibly formed by Ano2, serve as effectors downstream of P2Y receptors in type I cells. While the role for TRPM5 in taste transduction is well established, the physiological significance of expression of CaCCs in type II cells remains to be elucidated. PMID:26530828

  19. Two highly homologous members of the ClC chloride channel family in both rat and human kidney.

    OpenAIRE

    Kieferle, S; Fong, P; Bens, M.; Vandewalle, A; Jentsch, T J

    1994-01-01

    We have cloned two closely related putative Cl- channels from both rat kidney (designated rClC-K1 and rClC-K2) and human kidney (hClC-Ka and hClC-Kb) by sequence homology to the ClC family of voltage-gated Cl- channels. While rClC-K1 is nearly identical to ClC-K1, a channel recently isolated by a similar strategy, rClC-K2 is 80% identical to rClC-K1 and is encoded by a different gene. hClC-Ka and hClC-Kb show approximately 90% identity, while being approximately 80% identical to the rat prote...

  20. The CLC-2 Chloride Channel Modulates ECM Synthesis, Differentiation, and Migration of Human Conjunctival Fibroblasts via the PI3K/Akt Signaling Pathway

    Science.gov (United States)

    Sun, Lixia; Dong, Yaru; Zhao, Jing; Yin, Yuan; Zheng, Yajuan

    2016-01-01

    Recent evidence suggests that chloride channels are critical for cell proliferation, migration, and differentiation. We examined the effects of transforming growth factor (TGF)-β1 on chloride channel expression and associations with human conjunctival fibroblast (HConF) biology. To investigate the potential role of chloride channel (CLC)-2 in migration, transition to myofibroblasts and extracellular matrix (ECM) synthesis of HconF, a small interfering RNA (siRNA) approach was applied. TGF-β1-induced migration and transition of fibroblasts to myofibroblasts characterized by α-smooth muscle actin (α-SMA) expression, supported by increased endogenous expression of CLC-2 protein and mRNA transcripts. ECM (collagen I and fibronectin) synthesis in HConF was enhanced by TGF-β1. CLC-2 siRNA treatment reduced TGF-β1-induced cell migration, transition of fibroblasts to myofibroblasts, and ECM synthesis of HConF. CLC-2 siRNA treatment in the presence of TGF-β1 inhibited phosphorylation of PI3K and Akt in HConF. These findings demonstrate that CLC-2 chloride channels are important for TGF-β1-induced migration, differentiation, and ECM synthesis via PI3K/Akt signaling in HConF. PMID:27294913

  1. Calcium-activated chloride channels in the apical region of mouse vomeronasal sensory neurons

    OpenAIRE

    Dibattista, Michele; Amjad, Asma; Maurya, Devendra Kumar; Sagheddu, Claudia; Montani, Giorgia; Tirindelli, Roberto; Menini, Anna

    2012-01-01

    The rodent vomeronasal organ plays a crucial role in several social behaviors. Detection of pheromones or other emitted signaling molecules occurs in the dendritic microvilli of vomeronasal sensory neurons, where the binding of molecules to vomeronasal receptors leads to the influx of sodium and calcium ions mainly through the transient receptor potential canonical 2 (TRPC2) channel. To investigate the physiological role played by the increase in intracellular calcium concentration in the api...

  2. Effects of chloride channel blockers on rat renal vascular responses to angiotensin II and norepinephrine

    DEFF Research Database (Denmark)

    Steendahl, Joen; Sørensen, Charlotte Mehlin; Salomonsson, Max;

    2003-01-01

    The aim of the present study was to investigate the role of Ca2+-activated Cl- channels in the renal vasoconstriction elicited by angiotensin II (ANG II) and norepinephrine (NE). Renal blood flow (RBF) was measured in vivo using electromagnetic flowmetry. Ratiometric photometry of fura 2 fluoresc......The aim of the present study was to investigate the role of Ca2+-activated Cl- channels in the renal vasoconstriction elicited by angiotensin II (ANG II) and norepinephrine (NE). Renal blood flow (RBF) was measured in vivo using electromagnetic flowmetry. Ratiometric photometry of fura 2......-[(2-cyclopentenyl-6,7-dichloro-2,3-dihydro-2-methyl-1-oxo-1H-inden-5-yl)oxy]acetic acid (IAA-94; 0.045 and 0.09 micromol/min) did not affect the vasoconstrictive responses of these compounds. Pretreatment with niflumic acid (50 microM) or IAA-94 (30 microM) for 2 min decreased baseline [Ca2+]i but did not change...

  3. Meroterpenoid Chrodrimanins Are Selective and Potent Blockers of Insect GABA-Gated Chloride Channels.

    Science.gov (United States)

    Xu, Yan; Furutani, Shogo; Ihara, Makoto; Ling, Yun; Yang, Xinling; Kai, Kenji; Hayashi, Hideo; Matsuda, Kazuhiko

    2015-01-01

    Meroterpenoid chrodrimanins, produced from Talaromyces sp. YO-2, are known to paralyze silkworm (Bombyx mori) larvae, but their target is unknown. We have investigated the actions of chrodrimanin B on ligand-gated ion channels of silkworm larval neurons using patch-clamp electrophysiology. Chrodrimanin B had no effect on membrane currents when tested alone at 1 μM. However, it completely blocked the γ-aminobutyric acid (GABA)-induced current and showed less pronounced actions on acetylcholine- and L-glutamate-induced currents, when delivered at 1 μM for 1 min prior to co-application with transmitter GABA. Thus, chrodrimanins were also tested on a wild-type isoform of the B. mori GABA receptor (GABAR) RDL using two-electrode voltage-clamp electrophysiology. Chrodrimanin B attenuated the peak current amplitude of the GABA response of RDL with an IC50 of 1.66 nM. The order of the GABAR-blocking potency of chrodrimanins B > D > A was in accordance with their reported insecticidal potency. Chrodrimanin B had no open channel blocking action when tested at 3 nM on the GABA response of RDL. Co-application with 3 nM chrodrimanin B shifted the GABA concentration response curve to a higher concentration and further increase of chrodrimanin B concentration to 10 nM; it reduced maximum current amplitude of the GABA response, pointing to a high-affinity competitive action and a lower affinity non-competitive action. The A282S;T286V double mutation of RDL, which impairs the actions of fipronil, hardly affected the blocking action of chrodrimanin B, indicating a binding site of chrodrimanin B distinct from that of fipronil. Chrodrimanin B showed approximately 1,000-fold lower blocking action on human α1β2γ2 GABAR compared to RDL and thus is a selective blocker of insect GABARs. PMID:25902139

  4. Meroterpenoid Chrodrimanins Are Selective and Potent Blockers of Insect GABA-Gated Chloride Channels.

    Directory of Open Access Journals (Sweden)

    Yan Xu

    Full Text Available Meroterpenoid chrodrimanins, produced from Talaromyces sp. YO-2, are known to paralyze silkworm (Bombyx mori larvae, but their target is unknown. We have investigated the actions of chrodrimanin B on ligand-gated ion channels of silkworm larval neurons using patch-clamp electrophysiology. Chrodrimanin B had no effect on membrane currents when tested alone at 1 μM. However, it completely blocked the γ-aminobutyric acid (GABA-induced current and showed less pronounced actions on acetylcholine- and L-glutamate-induced currents, when delivered at 1 μM for 1 min prior to co-application with transmitter GABA. Thus, chrodrimanins were also tested on a wild-type isoform of the B. mori GABA receptor (GABAR RDL using two-electrode voltage-clamp electrophysiology. Chrodrimanin B attenuated the peak current amplitude of the GABA response of RDL with an IC50 of 1.66 nM. The order of the GABAR-blocking potency of chrodrimanins B > D > A was in accordance with their reported insecticidal potency. Chrodrimanin B had no open channel blocking action when tested at 3 nM on the GABA response of RDL. Co-application with 3 nM chrodrimanin B shifted the GABA concentration response curve to a higher concentration and further increase of chrodrimanin B concentration to 10 nM; it reduced maximum current amplitude of the GABA response, pointing to a high-affinity competitive action and a lower affinity non-competitive action. The A282S;T286V double mutation of RDL, which impairs the actions of fipronil, hardly affected the blocking action of chrodrimanin B, indicating a binding site of chrodrimanin B distinct from that of fipronil. Chrodrimanin B showed approximately 1,000-fold lower blocking action on human α1β2γ2 GABAR compared to RDL and thus is a selective blocker of insect GABARs.

  5. Donnan effect on chloride ion distribution as a determinant of body fluid composition that allows action potentials to spread via fast sodium channels

    Directory of Open Access Journals (Sweden)

    Kurbel Sven

    2011-05-01

    Full Text Available Abstract Proteins in any solution with a pH value that differs from their isoelectric point exert both an electric Donnan effect (DE and colloid osmotic pressure. While the former alters the distribution of ions, the latter forces water diffusion. In cells with highly Cl--permeable membranes, the resting potential is more dependent on the cytoplasmic pH value, which alters the Donnan effect of cell proteins, than on the current action of Na/K pumps. Any weak (positive or negative electric disturbances of their resting potential are quickly corrected by chloride shifts. In many excitable cells, the spreading of action potentials is mediated through fast, voltage-gated sodium channels. Tissue cells share similar concentrations of cytoplasmic proteins and almost the same exposure to the interstitial fluid (IF chloride concentration. The consequence is that similar intra- and extra-cellular chloride concentrations make these cells share the same Nernst value for Cl-. Further extrapolation indicates that cells with the same chloride Nernst value and high chloride permeability should have similar resting membrane potentials, more negative than -80 mV. Fast sodium channels require potassium levels >20 times higher inside the cell than around it, while the concentration of Cl- ions needs to be >20 times higher outside the cell. When osmotic forces, electroneutrality and other ions are all taken into account, the overall osmolarity needs to be near 280 to 300 mosm/L to reach the required resting potential in excitable cells. High plasma protein concentrations keep the IF chloride concentration stable, which is important in keeping the resting membrane potential similar in all chloride-permeable cells. Probable consequences of this concept for neuron excitability, erythrocyte membrane permeability and several features of circulation design are briefly discussed.

  6. Characterization of a critical role for CFTR chloride channels in cardioprotection against ischemia/reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Sunny Yang XIANG; Linda L YE; LI-lu Marie DUAN; Li-hui LIU; Zhi-dong GE; John A AUCHAMPACH; Garrett J GROSS; Dayue Darrel DUAN

    2011-01-01

    Aim: To further characterize the functional role of cystic fibrosis transmembrane conductance regulator (CFTR) in early and late (second window) ischemic preconditioning (IPC)- and postcondtioning (POC)-mediated cardioprotection against ischemia/reperfusion (I/R) injury.Methods: CFTR knockout (CFTR-/-) mice and age- and gender-matched wild-type (CFTR+/+) and heterozygous (CFTR+/-) mice were used.In in vivo studies, the animals were subjected to a 30-min coronary occlusion followed by a 40-min reperfusion. In ex vivo (isolate heart) studies, a 45-min global ischemia was applied. To evaluate apoptosis, the level of activated caspase 3 and TdT-mediated dUTP-X nick end labeling (TUNEL) were examined.Results: In the in vivo I/R models, early IPC significantly reduced the myocardial infarct size in wild-type (CFTR+/+) (from 40.4%±5.3% to 10.4%±2.0%, n=8, P<0.001) and heterozygous (CFTR+/-) littermates (from 39.4%±2.4% to 15.4%±5.1%, n=6, P<0.001) but failed to protect CFTR knockout (CFTR-/-) mice from I/R induced myocardial infarction (46.9%±6.2% vs 55.5%±7.8%, n=6, P>0.5). Similar results were observed in the in vivo late IPC experiments. Furthermore, in both in vivo and ex vivo I/R models, POC significantly reduced myocardial infarction in wild-type mice, but not in CFTR knockout mice. In ex vivo I/R models, targeted inactivation of CFTRgene abolished the protective effects of IPC against I/R-induced apoptosis.Conclusion: These results provide compelling evidence for a critical role for CFTR Cl- channels in IPC- and POC-mediated cardioprotection against I/R-induced myocardial injury.

  7. Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole-cell oscillations in smooth muscle cells

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian; Aalkjær, Christian; Nilsson, Holger;

    2007-01-01

    -frequency waves may transform into high-frequency whole-cell calcium oscillations. Simultaneously, multiple cells synchronize leading to rhythmic generation of tension. We present a mathematical model of vascular smooth muscle cells that aims at characterizing this sudden transition. Simulations show calcium...... onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion. Key words: Vasomotion, Chloride channel, cGMP, Mathematical model, Calcium waves....

  8. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace of Vibrio cholerae.

    Directory of Open Access Journals (Sweden)

    Tanaya Chatterjee

    Full Text Available Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX and Accessory cholera enterotoxin (Ace secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC inhibitors, namely CaCCinh-A01, digallic acid (DGA and tannic acid. Biophysical studies indicate that the unfolding (induced by urea free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders.

  9. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace) of Vibrio cholerae

    Science.gov (United States)

    Chatterjee, Tanaya; Sheikh, Irshad Ali; Chakravarty, Devlina; Chakrabarti, Pinak; Sarkar, Paramita; Saha, Tultul; Chakrabarti, Manoj K.; Hoque, Kazi Mirajul

    2015-01-01

    Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX) and Accessory cholera enterotoxin (Ace) secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC) inhibitors, namely CaCCinh-A01, digallic acid (DGA) and tannic acid. Biophysical studies indicate that the unfolding (induced by urea) free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD) simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders. PMID:26540279

  10. Adenosine regulates a chloride channel via protein kinase C and a G protein in a rabbit cortical collecting duct cell line.

    OpenAIRE

    Schwiebert, E. M.; Karlson, K H; Friedman, P A; Dietl, P.; Spielman, W S; Stanton, B.A.

    1992-01-01

    We examined the regulation by adenosine of a 305-pS chloride (Cl-) channel in the apical membrane of a continuous cell line derived from rabbit cortical collecting duct (RCCT-28A) using the patch clamp technique. Stimulation of A1 adenosine receptors by N6-cyclohexyladenosine (CHA) activated the channel in cell-attached patches. Phorbol 12,13-didecanoate and 1-oleoyl 2-acetylglycerol, activators of protein kinase C (PKC), mimicked the effect of CHA, whereas the PKC inhibitor H7 blocked the ac...

  11. Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole cell oscillations in smooth muscle cells

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; Aalkjær, Christian; Nilsson, Holger; Matchkov, Vladimir V; Freiberg, Jacob; Holstein-Rathlou, N.-H.

    2007-01-01

    waves sweeping through the cytoplasm when the sarcoplasmic reticulum (SR) is stimulated to release calcium. A rise in cGMP leads to the experimentally observed transition from waves to whole cell calcium oscillations. At the same time, membrane potential starts to oscillate and the frequency...... approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes a uniform opening of L-type calcium...

  12. The Effects of the KCNQ Openers Retigabine and Flupirtine on Myotonia in Mammalian Skeletal Muscle Induced by a Chloride Channel Blocker

    OpenAIRE

    Min-Jon Lin; George Hsiao; Ching-Chyuan Su; Wen-Shan Zei; Tzu-Rong Su

    2012-01-01

    The purpose of this study was to investigate the effect of KCNQ (potassium channel, voltage-gated, KQT-like subfamily) openers in preventing myotonia caused by anthracene-9-carboxylic acid (9-AC, a chloride channel blocker). An animal model of myotonia can be elicited in murine skeletal muscle by 9-AC treatment. KCNQ openers, such as retigabine and flupirtine, can inhibit the increased twitch amplitude (0.1 Hz stimulation) and reduce the tetanic fade (20 Hz stimulations) observed in the prese...

  13. Recessive Mutations in the Putative Calcium-Activated Chloride Channel Anoctamin 5 Cause Proximal LGMD2L and Distal MMD3 Muscular Dystrophies

    OpenAIRE

    Bolduc, Véronique; Marlow, Gareth; Boycott, Kym M; Saleki, Khalil; Inoue, Hiroshi; Kroon, Johan; Itakura, Mitsuo; Robitaille, Yves; Parent, Lucie; Baas, Frank; Mizuta, Kuniko; Kamata, Nobuyuki; Richard, Isabelle; Linssen, Wim H.J.P.; Mahjneh, Ibrahim

    2010-01-01

    The recently described human anion channel Anoctamin (ANO) protein family comprises at least ten members, many of which have been shown to correspond to calcium-activated chloride channels. To date, the only reported human mutations in this family of genes are dominant mutations in ANO5 (TMEM16E, GDD1) in the rare skeletal disorder gnathodiaphyseal dysplasia. We have identified recessive mutations in ANO5 that result in a proximal limb-girdle muscular dystrophy (LGMD2L) in three French Canadi...

  14. AB095. Increased expression of TMEM16A/Ano1 chloride channel associated with diabetic erectile dysfunction

    Science.gov (United States)

    Ruan, Yajun; Chen, Yingwei; Li, Mingchao; Wang, Tao; Yang, Jun; Rao, Ke; Wang, Shaogang; Yang, Weimin; Liu, Jihong; Ye, Zhangqun

    2016-01-01

    Objective To investigate the presence, location and functional role of TMEM16A/anotamin-1 (Ano1) calcium-activated chloride channel (CaCC) in the penile of rats with diabetic erectile dysfunction. Methods Eight-week-old male Sprague-Dawley (SD) rats were administrated streptozotocin (diabetic) or citrate buffer (control) randomly. Erectile function was measured by cavernous nerve electrostimulation at 12th week after diabetes was induced. The effect of Ano1 specific inhibitor—T16Ainh-A01 on intracavernous pressure (ICP) was evaluated. Then the penile tissues were harvested for molecular exploration. Real-time PCR and Western Blotting were used to assess the expression of Ano1 in penile tissues. Immunofluorescent labelling of penile tissue allowed localization of Ano1. Cavernous smooth muscle cell (CSMC) was cultured in high glucose medium. The change of Ano1 was measured using Western Blotting. The proliferation of CSMC was evaluated by cell counting kit-8 (CCK-8). Results Erectile function was impaired in diabetic rats. The expression of Ano1 was increased in rats with diabetic erectile dysfunction at mRNA and protein levels. Immunofluorescent labelling revealed the presence of Ano1 mainly in cavernous smooth muscle cells. The inhibition of Ano1 increased the ICP of DED rats. High glucose in vitro enhanced the proliferation of CSMC and the expression level of Ano1. Conclusions Ano1 is expressed in rat penile tissue and is increased with diabetes mellitus. The inhibition of Ano1 increased the ICP of DED rats. The alerted Ano1 may be associated with diabetic erectile dysfunction. It is a potential therapy target for ED in the future.

  15. Control of Energy Density inside a Disordered Medium by Coupling to Open or Closed Channels.

    Science.gov (United States)

    Sarma, Raktim; Yamilov, Alexey G; Petrenko, Sasha; Bromberg, Yaron; Cao, Hui

    2016-08-19

    We demonstrate experimentally the efficient control of light intensity distribution inside a random scattering system. The adaptive wave front shaping technique is applied to a silicon waveguide containing scattering nanostructures, and the on-chip coupling scheme enables access to all input spatial modes. By selectively coupling the incident light to the open or closed channels of the disordered system, we not only vary the total energy stored inside the system by a factor of 7.4, but also change the energy density distribution from an exponential decay to a linear decay and to a profile peaked near the center. This work provides an on-chip platform for controlling light-matter interactions in turbid media. PMID:27588875

  16. Control of energy density inside disordered medium by coupling to open or closed channels

    CERN Document Server

    Sarma, Raktim; Petrenko, Sasha; Bromberg, Yaron; Cao, Hui

    2016-01-01

    We demonstrate experimentally an efficient control of light intensity distribution inside a random scattering system. The adaptive wavefront shaping technique is applied to a silicon waveguide containing scattering nanostructures, and the on-chip coupling scheme enables access to all input spatial modes. By selectively coupling the incident light to open or closed channels of the disordered system, we not only vary the total energy stored inside the system by 7.4 times, but also change the energy density distribution from an exponential decay to a linear decay and to a profile peaked near the center. This work provides an on-chip platform for controlling light-matter interactions in turbid media.

  17. Synthesis of a tritium labeled tetrafluoro-substituted aryl azide photoaffinity labeling agent for chloride channels. Application of [3H]-sodium borohydride-cobalt chloride to tritium labeling

    International Nuclear Information System (INIS)

    5-Nitro-2-[N-3-(4-azido-2,3,5,6-tetrafluorophenyl)-propylamino]-benzoic acid (FAzNPPB), a photoaffinity analog of the potent epithelial chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) has been prepared in five steps from commercially available 4-amino-2,3,5,6-tetrafluorobenzonitrile. The main feature of this synthesis was the use of NaBH4-CoCl2 to convert an aryl-substituted alkenyl nitrile precursor to the corresponding alkyl amine. The feasibility of this approach and the stoichiometry were developed by model work with cinnamonitrile. Using sodium borotritide-cobalt chloride, [3H]-FAzNPPB (specific activity 13.9 mCi/mmol, radiochemical purity >99%) was prepared in three steps from (E)-4-amino-2,3,5,6-tetrafluoro-cinnamonitrile. [3H]-Sodium borohydride, cobalt chloride, azide, photaffinity, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB). (author)

  18. The novel isoxazoline ectoparasiticide fluralaner: selective inhibition of arthropod γ-aminobutyric acid- and L-glutamate-gated chloride channels and insecticidal/acaricidal activity.

    Science.gov (United States)

    Gassel, Michael; Wolf, Christian; Noack, Sandra; Williams, Heike; Ilg, Thomas

    2014-02-01

    Isoxazolines are a novel class of parasiticides that are potent inhibitors of γ-aminobutyric acid (GABA)-gated chloride channels (GABACls) and L-glutamate-gated chloride channels (GluCls). In this study, the effects of the isoxazoline drug fluralaner on insect and acarid GABACl (RDL) and GluCl and its parasiticidal potency were investigated. We report the identification and cDNA cloning of Rhipicephalus (R.) microplus RDL and GluCl genes, and their functional expression in Xenopus laevis oocytes. The generation of six clonal HEK293 cell lines expressing Rhipicephalus microplus RDL and GluCl, Ctenocephalides felis RDL-A285 and RDL-S285, as well as Drosophila melanogaster RDLCl-A302 and RDL-S302, combined with the development of a membrane potential fluorescence dye assay allowed the comparison of ion channel inhibition by fluralaner with that of established insecticides addressing RDL and GluCl as targets. In these assays fluralaner was several orders of magnitude more potent than picrotoxinin and dieldrin, and performed 5-236 fold better than fipronil on the arthropod RDLs, while a rat GABACl remained unaffected. Comparative studies showed that R. microplus RDL is 52-fold more sensitive than R. microplus GluCl to fluralaner inhibition, confirming that the GABA-gated chloride channel is the primary target of this new parasiticide. In agreement with the superior RDL on-target activity, fluralaner outperformed dieldrin and fipronil in insecticidal screens on cat fleas (Ctenocephalides felis), yellow fever mosquito larvae (Aedes aegypti) and sheep blowfly larvae (Lucilia cuprina), as well as in acaricidal screens on cattle tick (R. microplus) adult females, brown dog tick (Rhipicephalus sanguineus) adult females and Ornithodoros moubata nymphs. These findings highlight the potential of fluralaner as a novel ectoparasiticide. PMID:24365472

  19. Relationship of Intracellular Free Ca2+ Concentration and Calcium-activated Chloride Channels of Pulmonary Artery Smooth Muscle Cells in Rats under Hypoxic Conditions

    Institute of Scientific and Technical Information of China (English)

    YANG Zhao; ZHANG Zhenxiang; XU Yongjian; LI Yaqing; YE Tao

    2006-01-01

    To investigate the relationship between intracellular free Ca2+ concentration ([Ca2+]i)and calcium-activated chloride (Clca) channels of pulmonary artery smooth muscle cells (PASMCs) in rats under acute and chronic hypoxic conditions, acute hypoxia-induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusion in vitro. The fluorescence Ca2+indicator Fura-2/AM was used to observe [Ca2+]i of rat PASMCs under normal and chronic hypoxic condition. The effect of Clca channels on PASMCs proliferation was assessed by MTT assay.The Clca channel blockersniflumic acid (NFA) and indaryloxyacetic acid (IAA-94) exerted inhibitory effects on acute hypoxia-evoked contractions in the pulmonary artery. Under chronic hypoxic condition, [Ca2+ ]i was increased. Under normoxic condition, [Ca2+]i was (123.63±18.98) nmol/L, and in hypoxic condition, [Ca2+]i was (281. 75±16.48) nmol/L (P<0.01). Under normoxic condition, [Ca2+]i showed no significant change and no effect on Clca channels was observed (P>0. 05). Chronic hypoxia increased [Ca2+]i which opened Clca channels. The NFA and IAA-94blocked the channels and decreased [Ca2+]i from (281. 75±16.48) nmol/L to (117.66±15.36)nmol/L (P<0.01). MTT assay showed that under chronic hypoxic condition NFA and IAA-94 decreased the value of absorbency (A value) from 0. 459±0. 058 to 0. 224±0. 025 (P<0.01).Hypoxia increased [Ca2+]i which opened Clca channels and had a positive-feedback in [Ca2+]i. Thismay play an important role in hypoxic pulmonary hypertension. Under chronic hypoxic condition,Clca channel may play a part in the regulation of proliferation of PASMCs.

  20. Protein and cell patterning in closed polymer channels by photoimmobilizing proteins on photografted poly(ethylene glycol) diacrylate

    DEFF Research Database (Denmark)

    Larsen, Esben Kjær Unmack; Mikkelsen, Morten Bo Lindholm; Larsen, Niels Bent

    2014-01-01

    Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we...... present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists...... shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest....

  1. A slow anion channel in guard cells, activating at large hyperpolarization, may be principal for stomatal closing.

    Science.gov (United States)

    Linder, B; Raschke, K

    1992-11-16

    Slowly activating anion channel currents were discovered at micromolar 'cytoplasmic' Ca2+ during patch-clamp measurements on guard-cell protoplasts of Vicia faba and Xanthium strumarium. They activated at potentials as low as -200 mV, with time constants between 5 and 60 s, and no inactivation. The broad voltage dependence exhibited a current maximum near -40 mV. The single-channel open time was in the order of seconds, and the unitary conductance was 33 ps, similar to that of the already described 'quick' anion channel of guard cells. Because of its activity at low potentials, the slow anion channel may be essential for the depolarization of the plasmalemma that is required for salt efflux during stomatal closing. PMID:1385219

  2. 公丁香提取物抑制CFTR氯离子通道的发现与研究%The extract of clove inhibits CFTR chloride channel

    Institute of Scientific and Technical Information of China (English)

    栾剑; 张耀方; 杨红

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial chloride chan‐nel .In recent years ,the blockers of CFTR become the new hot spot in the treatment of secretory di‐arrhea .The aim of this research is using high‐throughput screening techniques screened blockers of CFTR chloride channel from traditional Chinese medicine .In this study ,after 40000 fractions of Chi‐nese herbal medicine have been screened ,clove extract was found .In cell‐based fluorescence assays and voltage clamp experiments ,the best active fraction‐E06 significantly blocks CFTR chloride chan‐nel .Therefore ,clove extract screened from traditional Chinese medicine blocks CFTR chloride chan‐nel and provides a theoretical basis for the in‐depth study of anti‐diarrheal drugs .%囊性纤维化跨膜电导调节因子(CFTR)是一种上皮细胞顶膜中表达的氯离子通道,是近年来治疗分泌型腹泻的新热点。利用高通量筛选技术,自中国传统中药中筛选能够抑制CFTR氯离子通道的中药组分。结果显示,自500种中草药的40000种中药组分中筛选到公丁香。经细胞荧光实验和电压膜片钳实验验证公丁香最佳活性孔———E06对CFTR具有明显的抑制作用,IC50=103 mg/L 。本研究结果为深入探讨公丁香的抗泻药物研发提供理论依据。

  3. Rapid recycling of ClC-2 chloride channels between plasma membrane and endosomes: role of a tyrosine endocytosis motif in surface retrieval.

    Science.gov (United States)

    Cornejo, Isabel; Niemeyer, María Isabel; Zúñiga, Leandro; Yusef, Yamil R; Sepúlveda, Francisco V; Cid, L Pablo

    2009-12-01

    ClC-2 chloride channel is present in the brain and some transporting epithelia where its function is poorly understood. We have now demonstrated that the surface channels are rapidly internalised and approximately the 70% of the surface membrane protein recycles after 4- to 8-min internalisation. Endocytosis of ClC-2 was dependent upon tyrosine 179 located within an endocytic motif. Rapid recycling accompanied by an even faster internalisation could account for the abundant presence of ClC-2 in intracellular membranous structures. At least a proportion of ClC-2 resides in lipid rafts. Use of beta-cyclodextrin led to an increase in cell surface channel, but, surprisingly, a decrease in functionally active channels. We suggest that ClC-2 requires residing in beta-cyclodextrin sensitive clusters with other molecules in order to remain active. Regulation of ClC-2 trafficking to and within the membrane could be a means of modulating its activity. PMID:19711355

  4. Rattlesnake Phospholipase A2 Increases CFTR-Chloride Channel Current and Corrects ∆F508CFTR Dysfunction: Impact in Cystic Fibrosis.

    Science.gov (United States)

    Faure, Grazyna; Bakouh, Naziha; Lourdel, Stéphane; Odolczyk, Norbert; Premchandar, Aiswarya; Servel, Nathalie; Hatton, Aurélie; Ostrowski, Maciej K; Xu, Haijin; Saul, Frederick A; Moquereau, Christelle; Bitam, Sara; Pranke, Iwona; Planelles, Gabrielle; Teulon, Jacques; Herrmann, Harald; Roldan, Ariel; Zielenkiewicz, Piotr; Dadlez, Michal; Lukacs, Gergely L; Sermet-Gaudelus, Isabelle; Ollero, Mario; Corringer, Pierre-Jean; Edelman, Aleksander

    2016-07-17

    Deletion of Phe508 in the nucleotide binding domain (∆F508-NBD1) of the cystic fibrosis transmembrane regulator (CFTR; a cyclic AMP-regulated chloride channel) is the most frequent mutation associated with cystic fibrosis. This mutation affects the maturation and gating of CFTR protein. The search for new high-affinity ligands of CFTR acting as dual modulators (correctors/activators) presents a major challenge in the pharmacology of cystic fibrosis. Snake venoms are a rich source of natural multifunctional proteins, potential binders of ion channels. In this study, we identified the CB subunit of crotoxin from Crotalus durissus terrificus as a new ligand and allosteric modulator of CFTR. We showed that CB interacts with NBD1 of both wild type and ∆F508CFTR and increases their chloride channel currents. The potentiating effect of CB on CFTR activity was demonstrated using electrophysiological techniques in Xenopus laevis oocytes, in CFTR-HeLa cells, and ex vivo in mouse colon tissue. The correcting effect of CB was shown by functional rescue of CFTR activity after 24-h ΔF508CFTR treatments with CB. Moreover, the presence of fully glycosylated CFTR was observed. Molecular docking allowed us to propose a model of the complex involving of the ABCβ and F1-like ATP-binding subdomains of ΔF508-NBD1. Hydrogen-deuterium exchange analysis confirmed stabilization in these regions, also showing allosteric stabilization in two other distal regions. Surface plasmon resonance competition studies showed that CB disrupts the ∆F508CFTR-cytokeratin 8 complex, allowing for the escape of ∆F508CFTR from degradation. Therefore CB, as a dual modulator of ΔF508CFTR, constitutes a template for the development of new anti-CF agents. PMID:27241308

  5. Recessive mutations in the putative calcium-activated chloride channel Anoctamin 5 cause proximal LGMD2L and distal MMD3 muscular dystrophies.

    Science.gov (United States)

    Bolduc, Véronique; Marlow, Gareth; Boycott, Kym M; Saleki, Khalil; Inoue, Hiroshi; Kroon, Johan; Itakura, Mitsuo; Robitaille, Yves; Parent, Lucie; Baas, Frank; Mizuta, Kuniko; Kamata, Nobuyuki; Richard, Isabelle; Linssen, Wim H J P; Mahjneh, Ibrahim; de Visser, Marianne; Bashir, Rumaisa; Brais, Bernard

    2010-02-12

    The recently described human anion channel Anoctamin (ANO) protein family comprises at least ten members, many of which have been shown to correspond to calcium-activated chloride channels. To date, the only reported human mutations in this family of genes are dominant mutations in ANO5 (TMEM16E, GDD1) in the rare skeletal disorder gnathodiaphyseal dysplasia. We have identified recessive mutations in ANO5 that result in a proximal limb-girdle muscular dystrophy (LGMD2L) in three French Canadian families and in a distal non-dysferlin Miyoshi myopathy (MMD3) in Dutch and Finnish families. These mutations consist of a splice site, one base pair duplication shared by French Canadian and Dutch cases, and two missense mutations. The splice site and the duplication mutations introduce premature-termination codons and consequently trigger nonsense-mediated mRNA decay, suggesting an underlining loss-of-function mechanism. The LGMD2L phenotype is characterized by proximal weakness, with prominent asymmetrical quadriceps femoris and biceps brachii atrophy. The MMD3 phenotype is associated with distal weakness, of calf muscles in particular. With the use of electron microscopy, multifocal sarcolemmal lesions were observed in both phenotypes. The phenotypic heterogeneity associated with ANO5 mutations is reminiscent of that observed with Dysferlin (DYSF) mutations that can cause both LGMD2B and Miyoshi myopathy (MMD1). In one MMD3-affected individual, defective membrane repair was documented on fibroblasts by membrane-resealing ability assays, as observed in dysferlinopathies. Though the function of the ANO5 protein is still unknown, its putative calcium-activated chloride channel function may lead to important insights into the role of deficient skeletal muscle membrane repair in muscular dystrophies. PMID:20096397

  6. Experimental study of the multi-gap multi-channel gas spark closing switch

    International Nuclear Information System (INIS)

    A coaxial multi-gap multi-channel spark switch with stainless-steel-spring ring gap electrodes is designed and investigated. The switch is triggered by a pulse applied to the cylindrical electrode outside the discharging channel through a parasitic capacitance coupling. The jitter of the switch is reduced by several short-distance gas gaps in series, and its inductance is reduced by a multi-channel discharge on account of the inductance isolation between the coils of the spring ring electrode. The experimental results indicate that the switch is of low inductance (14-30 nH), low jitter (∼3 ns), and stable breakdown performance

  7. Experimental Study of the Multi-gap Multi-channel Gas Spark Closing Switch

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A coaxial multi-gap multi-channel spark switch with stainless-steel-spring ring gap electrodes is designed and investigated. The switch is triggered by a pulse applied to the cylindrical electrode outside the discharging channel through a parasitic capacitance coupling. The jitter of the switch is reduced by several short-distance gas gaps in series, and its inductance is reduced by a multi-channel discharge on account of the inductance isolation between the coils of the spring ring electrode. The experimental results indicate that the switch is of low inductance (15~30 nH),low jitter (~3 ns), and stable breakdown performance.

  8. Chloride equilibrium potential in salamander cones

    Directory of Open Access Journals (Sweden)

    Bryson Eric J

    2004-12-01

    Full Text Available Abstract Background GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca and then determined the reversal potential for the current component that was inhibited by the Cl- channel blocker, niflumic acid. With this method, ECl was found to average -46 mV. In a complementary approach, we used a Cl-sensitive dye, MEQ, to measure the Cl- flux produced by depolarization with elevated concentrations of K+. The membrane potentials produced by the various high K+ solutions were measured in separate current clamp experiments. Consistent with electrophysiological experiments, MEQ fluorescence measurements indicated that ECl was below -36 mV. Conclusions The results of this study indicate that ECl is close to the dark resting potential. This will minimize the impact of chloride-dependent presynaptic mechanisms in cone terminals involving GABAa receptors, glutamate transporters and ICl(Ca.

  9. Ca2+-induced activation and irreversible inactivation of chloride channels in the perfused plasmalemma of Nitellopsis obtusa.

    Science.gov (United States)

    Kataev, A A; Zherelova, O M; Berestovsky, G N

    1984-12-01

    Experiments were carried out on the algal cells with removed tonoplast using both continuous intracellular perfusion and voltage clamp on plasmalemma. The transient plasmalemma current induced by depolarization disappeared upon perfusion with the Ca2+-chelating agent, EGTA, since the voltage-dependent calcium channels lost their ability to activate. Subsequent replacement of the perfusion medium containing EGTA by another with Ca2+ for clamped plasmalemma (-100 mV) induced an inward C1- current which showed both activation and inactivation. The maximal amplitude of the current at [C1-]in = 15 mmol/l (which is similar to that in native cells) was approximately twice that in electrically excited cell in vivo. The inactivation of C1 channels in the presence of internal Ca2+ was irreversible and had a time constant of 1-3 min. This supports our earlier suggestion (Lunevsky et al. 1983) that the inactivation of C1 channels in an intact cell (with a time constant of 1-3 s) is due to a decrease in Ca2+ concentration rather than to the activity of their own inactivation mechanism. The C1 channel selectivity sequence was following: C1- much greater than CH3SO-4 approximately equal to K+ much greater than SO2-4 (PK/PSO4 approximately 10). Activation of one half the channels occurs at a Ca2+ concentration of 2 X 10(-5) mol/l. Sr2+ also (though to a lesser extent) activated C1 channels but had to be present in a much more higher concentration than Ca2+. Mg2+ and Ba2+ appeared ineffective. Ca2+ activation did not, apparently, require participation of water-soluble intermediator including ATP. Thus, C1 channel functioning is controlled by Ca2+-, Sr2+-sensitive elements of the subplasmalemma cytoskeleton. PMID:6099298

  10. Altered expression of renal bumetanide-sensitive sodium-pota-ssium-2 chloride cotransporter and Cl- channel -K2 gene in angiotensin Ⅱ-infused hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    YE Tao; LIU Zhi-quan; SUN Chao-feng; ZHENG Yong; MA Ai-qun; FANG Yuan

    2005-01-01

    Background Little information is available regarding the effect of angiotensin Ⅱ (Ang Ⅱ) on the bumetanide-sensitive sodium-potassium-2 chloride cotransporter (NKCC2), the thiazide-sensitive sodium-chloride cotransporter (NCC), and the Cl- channel (CLC)-K2 at both mRNA and protein expression level in Ang Ⅱ-induced hypertensive rats. This study was conducted to investigate the influence of Ang Ⅱ with chronic subpressor infusion on nephron-specific gene expression of NKCC2, NCC and CLC-K2. Results Ang Ⅱ significantly increased blood pressure and up-regulated NKCC2 mRNA and protein expression in the kidney. Expression of CLC-K2 mRNA in the kidney increased 1.6 fold (P<0.05).There were no changes in NCC mRNA or protein expression in AngII-treated rats versus control. Conclusions Chronic subpressor Ang Ⅱ infusion can significantly alter NKCC2 and CLC-K2 mRNA expression in the kidney, and protein abundance of NKCC2 in kidney is positively regulated by Ang Ⅱ. These effects may contribute to enhanced renal Na+ and Cl- reabsorption in response to Ang Ⅱ.

  11. Expression and Function of CLC and Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channels in Renal Epithelial Tubule Cells: Pathophysiological Implications

    OpenAIRE

    Alain Vandewalle

    2007-01-01

    Cl- channels play important roles in the regulation of a variety of functions, includingelectrical excitability, cell volume regulation, transepithelial transport and acidification ofcellular organelles. They are expressed in plasma membranes or reside in intracellularorganelles. A large number of Cl- channels with different functions have been identified.Some of them are highly expressed in the kidney. They include members of the CLC Clchannelfamily: ClC-K1 (or ClC-Ka), ClC-K2 (or ClC-Kb) an...

  12. Effects of glycoprotein Ⅱb/Ⅲa antagonists and chloride channel blockers on platelet cytoplasmic free calcium

    Institute of Scientific and Technical Information of China (English)

    YIN Song-mei; XIE Shuang-feng; NIE Da-nian; LI Yi-qing; LI Hai-ming; MA Li-ping; WANG Xiu-ju; WU Yu-dan; FENG Jian-hong

    2005-01-01

    @@ Platelet activation plays an important role in thrombosis. Platelet glycoprotein Ⅱb/Ⅲa (GP Ⅱb/Ⅲa) is the receptor of fibrinogen. Platelet cross-linking with fibrinogen through GPⅡb/Ⅲa is the process of thrombosis. Ca2+ is an important intracellular second messenger in platelet activation. It has been reported that GPⅡb/Ⅲa receptors were involved in the calcium influx of activated platelet, and GPⅡb/Ⅲa receptor had characteristics of calcium channel or an adjacent calcium channel.

  13. Cell swelling activates ATP-dependent voltage-gated chloride channels in M-1 mouse cortical collecting duct cells.

    Science.gov (United States)

    Meyer, K; Korbmacher, C

    1996-09-01

    In the present study we used whole-cell patch clamp recordings to investigate swelling-activated Cl-currents (ICl-swell) in M-1 mouse cortical collecting duct (CCD) cells. Hypotonic cell swelling reversibly increased the whole-cell Cl- conductance by about 30-fold. The I-V relationship was outwardly-rectifying and ICl-swell displayed a characteristic voltage-dependence with relatively fast inactivation upon large depolarizing and slow activation upon hyperpolarizing voltage steps. Reversal potential measurements revealed a selectivity sequence SCN- > I- > Br- > Cl- > > gluconate. ICl-swell was inhibited by tamoxifen, NPPB (5-nitro-2(3-phenylpropylamino)-benzoate), DIDS (4,4'-diisothiocyanostilbene-2,2'-disulphonic acid), flufenamic acid, niflumic acid, and glibenclamide, in descending order of potency. Extracellular cAMP had no significant effect. ICl-swell was Ca2+ independent, but current activation depended on the presence of a high-energy gamma-phosphate group from intracellular ATP or ATP gamma S. Moreover, it depended on the presence of intracellular Mg2+ and was inhibited by staurosporine, which indicates that a phosphorylation step is involved in channel activation. Increasing the cytosolic Ca2+ concentration by using ionomycin stimulated Cl- currents with a voltage dependence different from that of ICl-swell. Analysis of whole-cell current records during early onset of ICl-swell and during final recovery revealed discontinuous step-like changes of the whole-cell current level which were not observed under nonswelling conditions. A single-channel I-V curve constructed using the smallest resolvable current transitions detected at various holding potentials and revealed a slope conductance of 55, 15, and 8 pS at +120, 0, and -120 mV, respectively. The larger current steps observed in these recordings had about 2, 3, or 4 times the size of the putative single-channel current amplitude, suggesting a coordinated gating of several individual channels or channel

  14. Multichannel Quantum Defect Study of the Perturber's Effect on the Overlapping Resonances in Rydberg Series for the Systems Involving 2 Closed and Many Open Channels

    International Nuclear Information System (INIS)

    The phase-shifted version of the multichannel quantum-defect theory (MQDT) was reformulated by disentangling the interloper spectrum from the perturbed dense Rydberg series for a systems involving 2 closed and more than 1 open channel. The theory was applied successfully to Martins and Zimmermann's photoionization spectra of the Rydberg series Cu I 3d9 4s(1D2) nd 2G9/2 perturbed by the interloper, 3d9 4p24F9/2, for which Cohen's 4 channel QDT had failed. The zero surface graphic of the perturbed Fano's asymmetry parameter q of the autoionization spectrum of dense Rydberg series by the interloper was determined by only two parameters for this system. It was used as a map to trace the transformation route of the 3 channel autoionization spectra to the 4 channel spectra when the channel coupling of the closed channels with a newly added open channel was turned on progressively

  15. Human AQP1 is a constitutively open channel that closes by a membrane-tension-mediated mechanism.

    Science.gov (United States)

    Ozu, Marcelo; Dorr, Ricardo A; Gutiérrez, Facundo; Politi, M Teresa; Toriano, Roxana

    2013-01-01

    This work presents experimental results combined with model-dependent predictions regarding the osmotic-permeability regulation of human aquaporin 1 (hAQP1) expressed in Xenopus oocyte membranes. Membrane elastic properties were studied under fully controlled conditions to obtain a function that relates internal volume and pressure. This function was used to design a model in which osmotic permeability could be studied as a pressure-dependent variable. The model states that hAQP1 closes with membrane-tension increments. It is important to emphasize that the only parameter of the model is the initial osmotic permeability coefficient, which was obtained by model-dependent fitting. The model was contrasted with experimental records from emptied-out Xenopus laevis oocytes expressing hAQP1. Simulated results reproduce and predict volume changes in high-water-permeability membranes under hypoosmotic gradients of different magnitude, as well as under consecutive hypo- and hyperosmotic conditions. In all cases, the simulated permeability coefficients are similar to experimental values. Predicted pressure, volume, and permeability changes indicate that hAQP1 water channels can transit from a high-water-permeability state to a closed state. This behavior is reversible and occurs in a cooperative manner among monomers. We conclude that hAQP1 is a constitutively open channel that closes mediated by membrane-tension increments. PMID:23332061

  16. Cloning and characterization of CLCN5, the human kidney chloride channel gene implicated in Dent disease (an X-linked hereditary nephrolithiasis)

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, S.E.; Van Bakel, I.; Craig, I.W. [Univ. of Oxford (United Kingdom)] [and others

    1995-10-10

    Dent disease, an X-linked familial renal tubular disorder, is a form of Fanconi syndrome associated with proteinuria, hypercalciuria, nephrocalcinosis, kidney stones, and eventual renal failure. We have previously used positional cloning to identify the 3{prime} part of a novel kidney-specific gene (initially termed hClC-K2, but now referred to as CLCN5), which is deleted in patients from one pedigree segregating Dent disease. Mutations that disrupt this gene have been identified in other patients with this disorder. Here we describe the isolation and characterization of the complete open reading frame of the human CLCN5 gene, which is predicted to encode a protein of 746 amino acids, with significant homology to all known members of the ClC family of voltage-gated chloride channels. CLCN5 belongs to a distinct branch of this family, which also includes the recently identified genes CLCN3 and CLCN4. We have shown that the coding region of CLCN5 is organized into 12 exons, spanning 25-30 kb of genomic DNA, and have determined the sequence of each exon-intron boundary. The elucidation of the coding sequence and exon-intron organization of CLCN5 will both expedite the evaluation of structure/function relationships of these ion channels and facilitate the screening of other patients with renal tubular dysfunction for mutations at this locus. 31 refs., 5 figs.

  17. The Effects of the KCNQ Openers Retigabine and Flupirtine on Myotonia in Mammalian Skeletal Muscle Induced by a Chloride Channel Blocker.

    Science.gov (United States)

    Su, Tzu-Rong; Zei, Wen-Shan; Su, Ching-Chyuan; Hsiao, George; Lin, Min-Jon

    2012-01-01

    The purpose of this study was to investigate the effect of KCNQ (potassium channel, voltage-gated, KQT-like subfamily) openers in preventing myotonia caused by anthracene-9-carboxylic acid (9-AC, a chloride channel blocker). An animal model of myotonia can be elicited in murine skeletal muscle by 9-AC treatment. KCNQ openers, such as retigabine and flupirtine, can inhibit the increased twitch amplitude (0.1 Hz stimulation) and reduce the tetanic fade (20 Hz stimulations) observed in the presence of 9-AC. Furthermore, the prolonged twitch duration of skeletal muscle was also inhibited by retigabine or flupirtine. Lamotrigine (an anticonvulsant drug) has a lesser effect on the muscle twitch amplitude, tetanic fade, and prolonged twitch duration as compared with KCNQ openers. In experiments using intracellular recordings, retigabine and flupirtine clearly reduced the firing frequencies of repetitive action potentials induced by 9-AC. These data suggested that KCNQ openers prevent the myotonia induced by 9-AC, at least partly through enhancing potassium conductance in skeletal muscle. Taken together, these results indicate that KCNQ openers are potential alternative therapeutic agents for the treatment of myotonia. PMID:22536291

  18. The Effects of the KCNQ Openers Retigabine and Flupirtine on Myotonia in Mammalian Skeletal Muscle Induced by a Chloride Channel Blocker

    Directory of Open Access Journals (Sweden)

    Tzu-Rong Su

    2012-01-01

    Full Text Available The purpose of this study was to investigate the effect of KCNQ (potassium channel, voltage-gated, KQT-like subfamily openers in preventing myotonia caused by anthracene-9-carboxylic acid (9-AC, a chloride channel blocker. An animal model of myotonia can be elicited in murine skeletal muscle by 9-AC treatment. KCNQ openers, such as retigabine and flupirtine, can inhibit the increased twitch amplitude (0.1 Hz stimulation and reduce the tetanic fade (20 Hz stimulations observed in the presence of 9-AC. Furthermore, the prolonged twitch duration of skeletal muscle was also inhibited by retigabine or flupirtine. Lamotrigine (an anticonvulsant drug has a lesser effect on the muscle twitch amplitude, tetanic fade, and prolonged twitch duration as compared with KCNQ openers. In experiments using intracellular recordings, retigabine and flupirtine clearly reduced the firing frequencies of repetitive action potentials induced by 9-AC. These data suggested that KCNQ openers prevent the myotonia induced by 9-AC, at least partly through enhancing potassium conductance in skeletal muscle. Taken together, these results indicate that KCNQ openers are potential alternative therapeutic agents for the treatment of myotonia.

  19. Geometrical construction of the S matrix and multichannel quantum defect theory for the two open and one closed channel system

    CERN Document Server

    Lee, C W

    2002-01-01

    The multichannel quantum defect theory (MQDT) is reformulated into the form of the configuration mixing (CM) method using the geometrical construction of the S matrix developed for the system involving two open and one closed channels. The reformulation is done by the phase renormalization method of Giusti-Suzor and Fano. The rather unconventional short-range reactance matrix K whose diagonal elements are not zero is obtained though the Lu-Fano plot becomes symmetrical. The reformulation of MQDT yields the partial cross section formulas analogous to Fano's resonance formula, which has not easily been available in other's work.

  20. Geometrical construction of the S matrix and multichannel quantum defect theory for the two open and one closed channel system

    International Nuclear Information System (INIS)

    The multichannel quantum defect theory (MQDT) is reformulated into the form of the configuration mixing (CM) method using the geometrical construction of the S matrix developed for the system involving two open and one closed channels. The reformulation is done by the phase renormalization method of Giusti-Suzor and Fano. The rather unconventional short-range reactance matrix K whose diagonal elements are not zero is obtained though the Lu-Fano plot becomes symmetrical. The reformulation of MQDT yields the partial cross section formulas analogous to Fano's resonance formula, which has not easily been available in other's work

  1. Boundary state in open string channel and open/closed string field theory

    OpenAIRE

    Isono, Hiroshi; Matsuo, Yutaka

    2005-01-01

    We generalize the idea of boundary states to open string channel. They describe the emission and absorption of the open string in the presence of intersecting D-branes. We study the algebra between such states under the star products of string field theory and confirm that they are projectors in a generalized sense. Based on this observation, we propose a modular dual description of Witten's open string field theory which seems to be an appropriate set-up to study D-branes by string field the...

  2. A yellow fluorescent protein-based assay for high-throughput screening of glycine and GABAA receptor chloride channels.

    Science.gov (United States)

    Kruger, Wade; Gilbert, Daniel; Hawthorne, Rebecca; Hryciw, Deanne H; Frings, Stephan; Poronnik, Philip; Lynch, Joseph W

    2005-06-01

    There is a significant clinical need to identify novel ligands with high selectivity and potency for GABA(A), GABA(C) and glycine receptor Cl- channels. Two recently developed, yellow fluorescent protein variants (YFP-I152L and YFP-V163S) are highly sensitive to quench by small anions and are thus suited to reporting anionic influx into cells. The aim of this study was to establish the optimal conditions for using these constructs for high-throughput screening of GABA(A), GABA(C) and glycine receptors transiently expressed in HEK293 cells. We found that a 70% fluorescence reduction was achieved by quenching YFP-I152L with a 10 s influx of I- ions, driven by an external I- concentration of at least 50 mM. The fluorescence quench was rapid, with a mean time constant of 3 s. These responses were similar for all anion receptor types studied. We also show the assay is sufficiently sensitive to measure agonist and antagonist concentration-responses using either imaging- or photomultiplier-based detection systems. The robustness, sensitivity and low cost of this assay render it suited for high-throughput screening of transiently expressed anionic ligand-gated channels. PMID:15862914

  3. Exact closed form expressions for outage probability of GSC receivers over Rayleigh fading channel subject to self-interference

    KAUST Repository

    Nam, Sungsik

    2010-11-01

    Previous work on performance analyses of generalized selection combining (GSC) RAKE receivers based on the signal to noise ratio focused on the development of methodologies to derive exact closed-form expressions for various performance measures. However, some open problems related to the performance evaluation of GSC RAKE receivers still remain to be solved such that an assessment of the impact of self-interference on the performance of GSC RAKE receivers. To have a full and exact understanding of the performance of GSC RAKE receivers, the outage probability of GSC RAKE receivers needs to be analyzed as closed-form expressions. The major difficulty in this problem is to derive some joint statistics of ordered exponential variates. With this motivation in mind, we capitalize in this paper on some new order statistics results to derive exact closed-form expressions for outage probability of GSC RAKE receivers subject to self-interference over independent and identically distributed Rayleigh fading channels. © 2010 IEEE.

  4. Up-Regulation of Interleukin-9 and the Interleukin-9-Associated Calcium-Activated Chloride Channel hCLCA1 in Nasal Mucosa Following In Vivo Allergen Challenge

    Directory of Open Access Journals (Sweden)

    Hauber Hans-Peter

    2007-03-01

    Full Text Available Interleukin (IL-9 is a pleiotropic T helper 2-type cytokine that has been shown to be up-regulated in allergic airway disease, including asthma. IL-9 has been demonstrated to be a potent stimulus for the production and secretion of mucus from airway epithelial cells via induction of a calcium-activated chloride channel, hCLCA1. The objective of this study was to investigate the expression of IL-9 and hCLCA1 following allergen challenge in the nasal mucosa of allergic rhinitis patients. Nasal biopsies were obtained from allergic rhinitis patients out of allergen season both before (baseline and after local antigen challenge with either ragweed or diluent (control. Immunohistochemistry and in situ hybridization were used to assess IL-9 protein and hCLCA1 messenger ribonucleic acid. Eosinophils and T cells were detected using immunohistochemistry. IL-9 and hCLCA1 were very low at baseline, and expression was significantly up-regulated following ragweed challenge. Whereas the number of eosinophils increased after allergen challenge, T-cell counts did not change significantly. The results of this study demonstrate the relationship between specific allergen challenge and expression of both IL-9 and hCLCA1, suggesting a possible mechanism for the increased production of mucus from airway epithelial cells in allergic rhinitis.

  5. The chloride intracellular channel protein CLIC5 is expressed at high levels in hair cell stereocilia and is essential for normal inner ear function.

    Science.gov (United States)

    Gagnon, Leona H; Longo-Guess, Chantal M; Berryman, Mark; Shin, Jung-Bum; Saylor, Katherine W; Yu, Heping; Gillespie, Peter G; Johnson, Kenneth R

    2006-10-01

    Although CLIC5 is a member of the chloride intracellular channel protein family, its association with actin-based cytoskeletal structures suggests that it may play an important role in their assembly or maintenance. Mice homozygous for a new spontaneous recessive mutation of the Clic5 gene, named jitterbug (jbg), exhibit impaired hearing and vestibular dysfunction. The jbg mutation is a 97 bp intragenic deletion that causes skipping of exon 5, which creates a translational frame shift and premature stop codon. Western blot and immunohistochemistry results confirmed the predicted absence of CLIC5 protein in tissues of jbg/jbg mutant mice. Histological analysis of mutant inner ears revealed dysmorphic stereocilia and progressive hair cell degeneration. In wild-type mice, CLIC5-specific immunofluorescence was detected in stereocilia of both cochlear and vestibular hair cells and also along the apical surface of Kolliker's organ during cochlear development. Refined immunolocalization in rat and chicken vestibular hair cells showed that CLIC5 is limited to the basal region of the hair bundle, similar to the known location of radixin. Radixin immunostaining appeared reduced in hair bundles of jbg mutant mice. By mass spectrometry and immunoblotting, CLIC5 was shown to be expressed at high levels in stereocilia of the chicken utricle, in an approximate 1:1 molar ratio with radixin. These results suggest that CLIC5 associates with radixin in hair cell stereocilia and may help form or stabilize connections between the plasma membrane and the filamentous actin core. PMID:17021174

  6. A closed-loop electronics cooling by implementing single phase impinging jet and mini channels heat exchanger

    International Nuclear Information System (INIS)

    This paper reports our works in the design and testing of a closed-loop electronics cooling system that adopts bi-technologies: single phase impinging jet and mini channels heat exchanger. The system has the cooling capacity of 200 W over a single chip with a hydraulic diameter of 12 mm. The equivalent heat flux is 177 W/cm2. The cooling system maintains the chip's surface temperature below 95 deg. C maximum when the ambient temperature is 30 deg. C. De-ionized water is the working fluid of the system. For the impinging jet, two different nozzles are designed and tested. The hydraulic diameters (d N) are 0.5 mm and 0.8 mm. The corresponding volume flow rates are 280 mL/min and 348 mL/min. Mini channels heat exchanger has 6 (six) copper tubes with the inner diameter of 1.27 mm and the total length of about 1 m. The cooling system has a mini diaphragm pump and a DC electric fan with the maximum power consumptions of 8.4 W and 0.96 W respectively. The coefficient of performance of the system is 21.4

  7. Experimental Study of Single Phase Flow in a Closed-Loop Cooling System with Integrated Mini-Channel Heat Sink

    Directory of Open Access Journals (Sweden)

    Lei Ma

    2016-06-01

    Full Text Available The flow and heat transfer characteristics of a closed-loop cooling system with a mini-channel heat sink for thermal management of electronics is studied experimentally. The heat sink is designed with corrugated fins to improve its heat dissipation capability. The experiments are performed using variable coolant volumetric flow rates and input heating powers. The experimental results show a high and reliable thermal performance using the heat sink with corrugated fins. The heat transfer capability is improved up to 30 W/cm2 when the base temperature is kept at a stable and acceptable level. Besides the heat transfer capability enhancement, the capability of the system to transfer heat for a long distance is also studied and a fast thermal response time to reach steady state is observed once the input heating power or the volume flow rate are varied. Under different input heat source powers and volumetric flow rates, our results suggest potential applications of the designed mini-channel heat sink in cooling microelectronics.

  8. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, J.; Kuriyama, K. (Kyoto Prefectural Univ. of Medicine (Japan))

    1990-05-01

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited (3H)flunitrazepam binding to benzodiazepine receptor, but not (3H)muscimol binding to GABAA receptor as well as t-(3H)butylbicycloorthobenzoate (( 3H) TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively (3H) flunitrazepam binding. On the other hand, the binding of beta-(3H)CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated (3H)muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-(3H)CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for (3H)flunitrazepam, (3H)muscimol and (3H)TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested.

  9. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    International Nuclear Information System (INIS)

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited [3H]flunitrazepam binding to benzodiazepine receptor, but not [3H]muscimol binding to GABAA receptor as well as t-[3H]butylbicycloorthobenzoate [( 3H] TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively [3H] flunitrazepam binding. On the other hand, the binding of beta-[3H]CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated [3H]muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-[3H]CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for [3H]flunitrazepam, [3H]muscimol and [3H]TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested

  10. Comparative Proteomics of Ovarian Cancer Aggregate Formation Reveals an Increased Expression of Calcium-activated Chloride Channel Regulator 1 (CLCA1).

    Science.gov (United States)

    Musrap, Natasha; Tuccitto, Alessandra; Karagiannis, George S; Saraon, Punit; Batruch, Ihor; Diamandis, Eleftherios P

    2015-07-10

    Ovarian cancer is a lethal gynecological disease that is characterized by peritoneal metastasis and increased resistance to conventional chemotherapies. This increased resistance and the ability to spread is often attributed to the formation of multicellular aggregates or spheroids in the peritoneal cavity, which seed abdominal surfaces and organs. Given that the presence of metastatic implants is a predictor of poor survival, a better understanding of how spheroids form is critical to improving patient outcome, and may result in the identification of novel therapeutic targets. Thus, we attempted to gain insight into the proteomic changes that occur during anchorage-independent cancer cell aggregation. As such, an ovarian cancer cell line, OV-90, was cultured in adherent and non-adherent conditions using stable isotope labeling with amino acids in cell culture (SILAC). Anchorage-dependent cells (OV-90AD) were grown in tissue culture flasks, whereas anchorage-independent cells (OV-90AI) were grown in suspension using the hanging-drop method. Cellular proteins from both conditions were then identified using LC-MS/MS, which resulted in the quantification of 1533 proteins. Of these, 13 and 6 proteins were up-regulated and down-regulated, respectively, in aggregate-forming cells compared with cells grown as monolayers. Relative gene expression and protein expression of candidates were examined in other cell line models of aggregate formation (TOV-112D and ES-2), which revealed an increased expression of calcium-activated chloride channel regulator 1 (CLCA1). Moreover, inhibitor and siRNA transfection studies demonstrated an apparent effect of CLCA1 on cancer cell aggregation. Further elucidation of the role of CLCA1 in the pathogenesis of ovarian cancer is warranted. PMID:26004777

  11. Formation of Tunable, Emulsion Micro-Droplets Utilizing Flow-Focusing Channels and a Normally-Closed Micro-Valve

    Directory of Open Access Journals (Sweden)

    Gwo-Bin Lee

    2013-07-01

    Full Text Available A mono-dispersed emulsion is of great significance in many chemical, biomedical and industrial applications. The current study reports a new microfluidic chip capable of forming tunable micro-droplets in liquids for emulsification applications. It can precisely generate size-tunable, uniform droplets using flow-focusing channels and a normally-closed valve, which is opened by a pneumatic suction force. Experimental data showed that micro-droplets with a diameter ranging from several to tens of micrometers could be precisely generated with a high uniformity. The droplet size is experimentally found to be dependent on the velocity of the dispersed-phase liquid, which is controlled by the deflection of the suction membrane. Emulsions with droplet sizes ranging from 5.5 to 55 μm are successfully observed. The variation in droplet sizes is from 3.8% to 2.5%. The micro-droplets have a uniform size and droplets smaller than those reported in previous studies are possible with this approach. This new microfluidic device can be promising for emulsification and other related applications.

  12. The propagation of pressure wave in closed channel filed of periodic alternate corks with the gas–liquid mixture and gas

    Directory of Open Access Journals (Sweden)

    Grigoryan Sh.A.

    2015-09-01

    Full Text Available The propagation of wave in closed channel filed of corks is considered. It is supposed that the discrete structure of corks is periodic. The dispersion equation of the Bloch wave number dependence on wave numbers of corks is derived. It is obtained the frequencies bands of transmitting waves.

  13. Layer by layer growth of silver chloride nanoparticle within the pore channels of SBA-15/SO3H mesoporous silica (AgClNP/SBA-15/SO3K): Synthesis, characterization and antibacterial properties

    Science.gov (United States)

    Rostamnia, Sadegh; Doustkhah, Esmail; Estakhri, Saba; Karimi, Ziba

    2016-02-01

    The growth of silver chloride nanoparticles within the pore channels of functionalized SBA-15 mesoporous was achieved by sequential dipping steps in alternating bath of potassium chloride and silver nitrate under ultrasound irradiation at pH=9. The effects of sequential dipping steps in growth of the AgCl nanoparticles have been studied. The growth and formation of AgCl nanoparticles inside the sulfonated SBA-15 were characterized by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Antibacterial activity of the synthesized materials was investigated against Escherichia coli (E.coli) using the conventional diffusion-disc method. The materials showed high antibacterial activity.

  14. 呼吸道上皮细胞钠/氯离子通道与支气管哮喘%Epithelial sodium and chloride channels and bronchial asthma

    Institute of Scientific and Technical Information of China (English)

    王雯; 吉宏龙

    2015-01-01

    支气管哮喘(简称哮喘)是一种慢性气道疾病,表现为气道高反应性和气道炎症导致的可逆性气道阻塞.研究显示,呼吸道上皮细胞钠/氯离子通道(ENaC/CFTR)调节黏液纤毛系统从而参与了慢性气道疾病的发病机制.ENaC及CFTR共同调节黏液的水质层,从而影响气道纤毛清除能力.调节上皮通道蛋白的特异性拮抗剂或激活剂将为哮喘和其他慢性气道疾病的预防和治疗开拓新的研究前景.%Bronchial asthma (asthma) is a chronic respiratory disease characterized by reversible airway obstruction with bronchial hyper-responsiveness and inflammation.Airway cilia system is implicated in the pathogenesis of chronic airway diseases.Epithelial sodium channels (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR) are closely related to the mucociliary clearance.ENaC and CFTR jointly adjust the water layer of mucus, which affects the airway cilia clearance ability.Specific antagonists or activating agents of ENaC and CFTR could be novel pharmaceutical interventions for the prevention and treatment of asthma as well as other chronic airway diseases.

  15. Rapid, Single-Molecule Assays in Nano/Micro-Fluidic Chips with Arrays of Closely Spaced Parallel Channels Fabricated by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Brian K. Canfield

    2014-08-01

    Full Text Available Cost-effective pharmaceutical drug discovery depends on increasing assay throughput while reducing reagent needs. To this end, we are developing an ultrasensitive, fluorescence-based platform that incorporates a nano/micro-fluidic chip with an array of closely spaced channels for parallelized optical readout of single-molecule assays. Here we describe the use of direct femtosecond laser machining to fabricate several hundred closely spaced channels on the surfaces of fused silica substrates. The channels are sealed by bonding to a microscope cover slip spin-coated with a thin film of poly(dimethylsiloxane. Single-molecule detection experiments are conducted using a custom-built, wide-field microscope. The array of channels is epi-illuminated by a line-generating red diode laser, resulting in a line focus just a few microns thick across a 500 micron field of view. A dilute aqueous solution of fluorescently labeled biomolecules is loaded into the device and fluorescence is detected with an electron-multiplying CCD camera, allowing acquisition rates up to 7 kHz for each microchannel. Matched digital filtering based on experimental parameters is used to perform an initial, rapid assessment of detected fluorescence. More detailed analysis is obtained through fluorescence correlation spectroscopy. Simulated fluorescence data is shown to agree well with experimental values.

  16. Rapid, single-molecule assays in nano/micro-fluidic chips with arrays of closely spaced parallel channels fabricated by femtosecond laser machining.

    Science.gov (United States)

    Canfield, Brian K; King, Jason K; Robinson, William N; Hofmeister, William H; Davis, Lloyd M

    2014-01-01

    Cost-effective pharmaceutical drug discovery depends on increasing assay throughput while reducing reagent needs. To this end, we are developing an ultrasensitive, fluorescence-based platform that incorporates a nano/micro-fluidic chip with an array of closely spaced channels for parallelized optical readout of single-molecule assays. Here we describe the use of direct femtosecond laser machining to fabricate several hundred closely spaced channels on the surfaces of fused silica substrates. The channels are sealed by bonding to a microscope cover slip spin-coated with a thin film of poly(dimethylsiloxane). Single-molecule detection experiments are conducted using a custom-built, wide-field microscope. The array of channels is epi-illuminated by a line-generating red diode laser, resulting in a line focus just a few microns thick across a 500 micron field of view. A dilute aqueous solution of fluorescently labeled biomolecules is loaded into the device and fluorescence is detected with an electron-multiplying CCD camera, allowing acquisition rates up to 7 kHz for each microchannel. Matched digital filtering based on experimental parameters is used to perform an initial, rapid assessment of detected fluorescence. More detailed analysis is obtained through fluorescence correlation spectroscopy. Simulated fluorescence data is shown to agree well with experimental values. PMID:25140634

  17. Cooling channels design analysis with chaotic laminar trajectory for closed cathode air-cooled PEM fuel cells using non-reacting numerical approach

    Science.gov (United States)

    N, W. Mohamed W. A.

    2015-09-01

    The thermal management of Polymer Electrolyte Membrane (PEM) fuel cells contributes directly to the overall power output of the system. For a closed cathode PEM fuel cell design, the use of air as a cooling agent is a non-conventional method due to the large heat load involved, but it offers a great advantage for minimizing the system size. Geometrical aspects of the cooling channels have been identified as the basic parameter for improved cooling performance. Numerical investigation using STAR-CCM computational fluid dynamics platform was applied for non-reacting cooling effectiveness study of various channel geometries for fuel cell application. The aspect ratio of channels and the flow trajectory are the parametric variations. A single cooling plate domain was selected with an applied heat flux of 2400 W/m2 while the cooling air are simulated at Reynolds number of 400 that corresponds to normal air flow velocities using standard 6W fans. Three channel designs of similar number of channels (20 channels) are presented here to analyze the effects of having chaotic laminar flow trajectory compared to the usual straight path trajectory. The total heat transfer between the cooling channel walls and coolant were translated into temperature distribution, maximum temperature gradient, average plate temperature and overall cooling effectiveness analyses. The numerical analysis shows that the chaotic flow promotes a 5% to 10% improvement in cooling effectiveness, depending on the single-axis or multi-axis flow paths applied. Plate temperature uniformity is also more realizable using the chaotic flow designs.

  18. Dual regulation of the native ClC-K2 chloride channel in the distal nephron by voltage and pH.

    Science.gov (United States)

    Pinelli, Laurent; Nissant, Antoine; Edwards, Aurélie; Lourdel, Stéphane; Teulon, Jacques; Paulais, Marc

    2016-09-01

    ClC-K2, a member of the ClC family of Cl(-) channels and transporters, forms the major basolateral Cl(-) conductance in distal nephron epithelial cells and therefore plays a central role in renal Cl(-) absorption. However, its regulation remains largely unknown because of the fact that recombinant ClC-K2 has not yet been studied at the single-channel level. In the present study, we investigate the effects of voltage, pH, Cl(-), and Ca(2+) on native ClC-K2 in the basolateral membrane of intercalated cells from the mouse connecting tubule. The ∼10-pS channel shows a steep voltage dependence such that channel activity increases with membrane depolarization. Intracellular pH (pHi) and extracellular pH (pHo) differentially modulate the voltage dependence curve: alkaline pHi flattens the curve by causing an increase in activity at negative voltages, whereas alkaline pHo shifts the curve toward negative voltages. In addition, pHi, pHo, and extracellular Ca(2+) strongly increase activity, mainly because of an increase in the number of active channels with a comparatively minor effect on channel open probability. Furthermore, voltage alters both the number of active channels and their open probability, whereas intracellular Cl(-) has little influence. We propose that changes in the number of active channels correspond to them entering or leaving an inactivated state, whereas modulation of open probability corresponds to common gating by these channels. We suggest that pH, through the combined effects of pHi and pHo on ClC-K2, might be a key regulator of NaCl absorption and Cl(-)/HCO3 (-) exchange in type B intercalated cells. PMID:27574292

  19. 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

  20. The activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator chloride channel%川陈皮素对囊性纤维化跨膜传导调节因子的激活作用

    Institute of Scientific and Technical Information of China (English)

    杨爽; 于波; 张耀方; 王雪; 杨红

    2013-01-01

    Aim of the present study is to investigate activation effect of nobiletin on cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel activity.CFTR-mediated iodide influx assay and patch-clamp tests were done on FRT cells stably co-transfected with human CFTR and EYFP/H148Q.Nobiletin potently activated CFTR chloride channel activity in a dose-and time-dependent manner.The CFTR blocker CFTRinh-172 could completely reverse the effect.Preliminary mechanism study indicated that nobiletin activated CFTR chloride channel through a direct binding way.In addition,ex vivo tests done on mice trachea showed that nobiletin time-dependently stimulated submucosal gland fluid secretion.Nobiletin may be a therapeutic lead compound in treating CFTR-related diseases including disseminated bronchiectasis.%本实验利用荧光淬灭实验和膜片钳技术在稳定表达人CFTR和荧光绿蛋白突变体EYFP/H148Q的Fischer大鼠甲状腺上皮细胞(Fischer rat thyroid,FRT)上,测定川陈皮素(nobiletin)对囊性纤维化跨膜传导因子(cystic fibrosis transmembrane conductance regulator,CFTR)氯离子通道的激活作用.结果发现,川陈皮素以剂量依赖的方式激活CFTR氯离子通道的C1-转运活性,且这种活性是快速、可逆的,并能够被CFTR特异性抑制剂CFTRinh-172完全抑制.初步的分子机制研究表明,川陈皮素是以与CFTR直接作用来激活通道活性的.进一步的研究结果显示,川陈皮素能够有效刺激小鼠气管黏膜下腺液体分泌速度.因此,川陈皮素可能发展成为治疗包括支气管扩张在内的CFTR相关疾病的先导药物.

  1. Dissociative electron attachment to DNA-diamine thin films: Impact of the DNA close environment on the OH{sup −} and O{sup −} decay channels

    Energy Technology Data Exchange (ETDEWEB)

    Boulanouar, Omar; Fromm, Michel; Mavon, Christophe [UMR CNRS 6249 Chrono-Environnement, Laboratoire de Chimie Physique et Rayonnements – Alain Chambaudet, LRC CEA, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon cedex (France); Cloutier, Pierre; Sanche, Léon [Groupe en Sciences des Radiations, Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Québec J1H 5N4 (Canada)

    2013-08-07

    We measure the desorption of anions stimulated by the impact of 0–20 eV electrons on highly uniform thin films of plasmid DNA-diaminopropane. The results are accurately correlated with film thickness and composition by AFM and XPS measurements, respectively. Resonant structures in the H{sup −}, O{sup −}, and OH{sup −} yield functions are attributed to the decay of transient anions into the dissociative electron attachment (DEA) channel. The diamine induces ammonium-phosphate bridges along the DNA backbone, which suppresses the DEA O{sup −} channel and in counter-part increases considerably the desorption of OH{sup −}. The close environment of the phosphate groups may therefore play an important role in modulating the rate and type of DNA damages induced by low energy electrons.

  2. The lecomte-ueda transformation and resonance structure in the multichannel quantum defect theory for the two open and one closed channel system

    International Nuclear Information System (INIS)

    The transformation devised by Lecomte and Ueda for the study of resonance structures in the multichannel quantum defect theory (MQDT) is used to analyze partial photofragmentation cross section formulas in MQDT analogous to Fano's resonance formula obtained in the previous work for the system involving two open and one closed channels. Detailed comparison of the MQDT results with the configuration mixing (CM) ones is made. Resonance structures and their geometrical relations in the MQDT formulation are revealed and classified by combining Lecomte and Ueda's theory with the geometrical method devised to study the coupling between background and resonance scatterings

  3. The lecomte-ueda transformation and resonance structure in the multichannel quantum defect theory for the two open and one closed channel system

    CERN Document Server

    Lee, C W

    2002-01-01

    The transformation devised by Lecomte and Ueda for the study of resonance structures in the multichannel quantum defect theory (MQDT) is used to analyze partial photofragmentation cross section formulas in MQDT analogous to Fano's resonance formula obtained in the previous work for the system involving two open and one closed channels. Detailed comparison of the MQDT results with the configuration mixing (CM) ones is made. Resonance structures and their geometrical relations in the MQDT formulation are revealed and classified by combining Lecomte and Ueda's theory with the geometrical method devised to study the coupling between background and resonance scatterings.

  4. Current-voltage characteristics of quantum-point contacts in the closed-channel regime: Transforming the bias voltage into an energy scale

    DEFF Research Database (Denmark)

    Gloos, K.; Utko, P.; Aagesen, M.;

    2006-01-01

    .2 mu m) contacts are typically found to consist of very short (similar to 0.2 mu m) barriers. We have mapped the height of the barrier as a function of the gate voltage, and found that its behavior differs strongly from that extrapolated using conventional bias spectroscopy in the open-channel regime......We investigate the I(V) characteristics (current versus bias voltage) of side-gated quantum-point contacts, defined in GaAs/AlxGa1-xAs heterostructures. These point contacts are operated in the closed-channel regime, that is, at fixed gate voltages below zero-bias pinch-off for conductance. Our...... we are using the channel length remains the only adjustable parameter since the barrier height can be experimentally determined. For short (similar to 0.06 mu m) contacts, the I(V)-derived lengths agree rather well with those estimated from the geometrical layout, whereas nominally long (similar to 1...

  5. Removal of gating in voltage-dependent ClC-2 chloride channel by point mutations affecting the pore and C-terminus CBS-2 domain.

    Science.gov (United States)

    Yusef, Yamil R; Zúñiga, Leandro; Catalán, Marcelo; Niemeyer, María Isabel; Cid, L Pablo; Sepúlveda, Francisco V

    2006-04-01

    Functional and structural studies demonstrate that Cl(-) channels of the ClC family have a dimeric double-barrelled structure, with each monomer contributing an identical pore. Studies with ClC-0, the prototype ClC channel, show the presence of independent mechanisms gating the individual pores or both pores simultaneously. A single-point mutation in the CBS-2 domain of ClC-0 has been shown to abolish slow gating. We have taken advantage of the high conservation of CBS domains in ClC channels to test for the presence of a slow gate in ClC-2 by reproducing this mutation (H811A). ClC-2-H811A showed faster opening kinetics and opened at more positive potentials than ClC-2. There was no difference in [Cl(-)](i) dependence. Additional neutralization of a putative pore gate glutamate side chain (E207V) abolished all gating. Resolving slow and fast gating relaxations, however, revealed that the H811A mutation affected both fast and slow gating processes in ClC-2. This suggests that slow and fast gating in ClC-2 are coupled, perhaps with slow gating contributing to the operation of the pore E207 as a protopore gate. PMID:16469788

  6. Berberine reduces cAMP-induced chloride secretion in T84 human colonic carcinoma cells through inhibition of basolateral KCNQ1 channels

    Directory of Open Access Journals (Sweden)

    BrianJosephHarvey

    2011-06-01

    Full Text Available Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl- secretion in distal colon. The aims of this study were to determine the molecular signalling mechanisms of action of berberine on Cl- secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC50 80  8 M. In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K+ current by 88%, suggesting inhibition of KCNQ1 K+ channels. Berberine did not affect either apical Cl- conductance or basolateral Na+-K+-ATPase activity. Berberine stimulated p38 MAPK, PKC and PKA, but had no effect on p42/p44 MAPK and PKC. However, berberine pre-treatment prevented stimulation of p42/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl- secretion was partially blocked by HBDDE (65 %, an inhibitor of PKC and to a smaller extent by inhibition of p38 MAPK with SB202190 (15 %. Berberine treatment induced an increase in association between PKC and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl- secretion through inhibition of basolateral KCNQ1 channels responsible for K+ recycling via a PKC-dependent pathway.

  7. Berberine Reduces cAMP-Induced Chloride Secretion in T84 Human Colonic Carcinoma Cells through Inhibition of Basolateral KCNQ1 Channels.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2011-01-01

    Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl(-) secretion in distal colon. The aims of this study were to determine the molecular signaling mechanisms of action of berberine on Cl(-) secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC(50) 80 ± 8 μM). In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K(+) current by 88%, suggesting inhibition of KCNQ1 K(+) channels. Berberine did not affect either apical Cl(-) conductance or basolateral Na(+)-K(+)-ATPase activity. Berberine stimulated p38 MAPK, PKCα and PKA, but had no effect on p42\\/p44 MAPK and PKCδ. However, berberine pre-treatment prevented stimulation of p42\\/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl(-) secretion was partially blocked by HBDDE (∼65%), an inhibitor of PKCα and to a smaller extent by inhibition of p38 MAPK with SB202190 (∼15%). Berberine treatment induced an increase in association between PKCα and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl(-) secretion through inhibition of basolateral KCNQ1 channels responsible for K(+) recycling via a PKCα-dependent pathway.

  8. Berberine Reduces cAMP-Induced Chloride Secretion in T84 Human Colonic Carcinoma Cells through Inhibition of Basolateral KCNQ1 Channels.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2012-02-01

    Berberine is a plant alkaloid with multiple pharmacological actions, including antidiarrhoeal activity and has been shown to inhibit Cl(-) secretion in distal colon. The aims of this study were to determine the molecular signaling mechanisms of action of berberine on Cl(-) secretion and the ion transporter targets. Monolayers of T84 human colonic carcinoma cells grown in permeable supports were placed in Ussing chambers and short-circuit current measured in response to secretagogues and berberine. Whole-cell current recordings were performed in T84 cells using the patch-clamp technique. Berberine decreased forskolin-induced short-circuit current in a concentration-dependent manner (IC(50) 80 +\\/- 8 muM). In apically permeabilized monolayers and whole-cell current recordings, berberine inhibited a cAMP-dependent and chromanol 293B-sensitive basolateral membrane K(+) current by 88%, suggesting inhibition of KCNQ1 K(+) channels. Berberine did not affect either apical Cl(-) conductance or basolateral Na(+)-K(+)-ATPase activity. Berberine stimulated p38 MAPK, PKCalpha and PKA, but had no effect on p42\\/p44 MAPK and PKCdelta. However, berberine pre-treatment prevented stimulation of p42\\/p44 MAPK by epidermal growth factor. The inhibitory effect of berberine on Cl(-) secretion was partially blocked by HBDDE ( approximately 65%), an inhibitor of PKCalpha and to a smaller extent by inhibition of p38 MAPK with SB202190 ( approximately 15%). Berberine treatment induced an increase in association between PKCalpha and PKA with KCNQ1 and produced phosphorylation of the channel. We conclude that berberine exerts its inhibitory effect on colonic Cl(-) secretion through inhibition of basolateral KCNQ1 channels responsible for K(+) recycling via a PKCalpha-dependent pathway.

  9. DNS and LES of turbulent flow in a closed channel featuring a pattern of hemispherical roughness elements

    International Nuclear Information System (INIS)

    Highlights: • LES/DNS studied fully developed turbulent flow on hemispherical roughness elements. • Effect of Reynolds number, element height, spacing and distribution pattern explored. • Roughness promotes energy transfer from streamwise Re stress to lateral component. • Element spacing changes reattachment point of boundary layer downstream of element. • Random element distribution pattern does not affect friction factor or mean velocity greatly. - Abstract: Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) were performed for fully-developed turbulent flow in channels with smooth walls and walls featuring hemispherical roughness elements at shear Reynolds numbers Reτ = 180 and 400, with the goal of studying the effect of these roughness elements on the wall-layer structure and on the friction factor. The LES and DNS approaches were verified first by comparison with existing DNS databases for smooth walls. Then, a parametric study for the hemispherical roughness elements was conducted, including the effects of shear Reynolds number, normalized roughness height (k+ = 10–20) and relative roughness spacing (s+/k+ = 2–6). The sensitivity study also included the effect of distribution pattern (regular square lattice vs. random pattern) of the roughness elements on the walls. The hemispherical roughness elements generate turbulence, thus increasing the friction factor with respect to the smooth-wall case, and causing a downward shift in the mean velocity profiles. The simulations revealed that the friction factor decreases with increasing Reynolds number and roughness spacing, and increases strongly with increasing roughness height. The effect of random element distribution on friction factor and mean velocities is however weak. In all cases, there is a clear cut between the inner layer near the wall, which is affected by the presence of the roughness elements, and the outer layer, which remains relatively unaffected. The study reveals

  10. Expressional changes of chloride channel in human temporal foci with intractable epilepsy%氯通道在难治性颞叶癫痫病灶内的表达变化

    Institute of Scientific and Technical Information of China (English)

    冯亚波; 姚红; 满晓; 杜怡峰; 陈春富; 尚伟; 郭华; 迟兆富

    2009-01-01

    目的 研究ClC-2、ClC-3氯通道在难治性癫痫病灶中表达的变化,并探讨这种分布和表达变化的意义.方法 取20例难治性癫痫患者手术切除的病灶及20例脑血管畸形患者手术切除的正常脑组织,分别采用SABC法对ClC-2、ClC_3氯通道免疫组化染色,采用RT-PCR方法检测ClC-2、ClC-3氯通道mRNA.RT-PCR凝胶电泳图像应用1D Image Analysis Software分析.结果 ClC-2、ClC-3氯通道在癫痫灶和正常脑组织中皆有表达,但RT-PCR半定量分析显示:在癫痫灶中ClC-2氯通道表达的相对密度(0.34±0.16)低于正常脑组织(0.81±0.11),差异具有显著性(P<0.05);而ClC-3氯通道在癫痫灶中的表达的相对密度(0.83±0.09)高于正常脑组织(0.53±0.14),差异具有显著性(P<0.05).结论 难治性癫痫病灶中ClC-2通道表达减少,ClC-3通道表达增加,可能是难治性癫痫发作频发且难以控制的原因之一,也可能为癫痫发作的继发性改变.%Objective To investigate the expressional changes of voltage-gated chloride channel CIC-2, CIC-3 in human temporal foci with intractable epilepsy. Methods The specimens were obtained from 20 patients with intractable temporal lobe epilepsy and 20 patients with arteriovenous malformation as control, lmmunohisto-chemistry and RT-PCR was used to detect the expression of CIC-2, CIC-3 chloride channel. The gel eleclrophore-sis images of RT-PCR were analysised by 1D Image Analysis Software. Results Chloride channel CIC-2 and CIC-3 expressed both in epileptic foci and the normal. Serni-quantitive RT-PCR showed that the relative density of CIC-2 mRNA expression in epileptic foci(0. 34 ±0. 16) was lower than that in the normal (0. 81 ±0. 11 ) (P< 0. 05 ) ;the relative density of CIC-3 mRNA in epileptic foci ( 0. 83 ± 0. 09 ) was higher than that in the normal (0.53 ±0. 14)(P<0.05). Conclusion The decrease of CIC-2 and the increase of CIC-3 in epileptic foci may be one of the reasons why the seizures in intractable

  11. Similar expression patterns of bestrophin-4 and cGMP dependent Ca2+-activated chloride channel activity in the vasculature

    DEFF Research Database (Denmark)

    Bouzinova, Elena V.; Larsen, Per; Matchkov, Vladimir; Nilsson, Holger; Aalkjær, Christian

    2008-01-01

    (abstract by Matchkov et. al) that siRNA mediated downregulation of bestrophin-4 is associated with the disappearance of a recently demonstrated2 cGMP-dependent Ca2+-activated Cl- current in vascular smooth muscle cells (SMCs). Here we study the distribution of bestrophin-4-and cGMP dependent Cl- channel...... expressed epitope) Western blot detected a ~65 kDa band in cell lysates from rat mesenteric small arteries and aorta, which was not seen in pulmonary arteries and when preincubated with the immunizing peptide. The distribution of bestrophin-4 mRNA and protein has a pattern similar to the cGMP-dependent Cl......- current in SMCs of different origins. Immunohistochemistry identified bestrophin-4 both in endothelial and SMCs of the vascular tree in the brain, heart, kidney and mesentery, but not in the lungs. We suggest that bestrophin-4 is important for the cGMP dependent, Ca2+ activated Cl- conductance in many...

  12. Closed-Loop Neuroprosthesis for Reach-to-Grasp Assistance: Combining Adaptive Multi-channel Neuromuscular Stimulation with a Multi-joint Arm Exoskeleton.

    Science.gov (United States)

    Grimm, Florian; Gharabaghi, Alireza

    2016-01-01

    Stroke patients with severe motor deficits cannot execute task-oriented rehabilitation exercises with their affected upper extremity. Advanced rehabilitation technology may support them in performing such reach-to-grasp movements. The challenge is, however, to provide assistance as needed, while maintaining the participants' commitment during the exercises. In this feasibility study, we introduced a closed-loop neuroprosthesis for reach-to-grasp assistance which combines adaptive multi-channel neuromuscular stimulation with a multi-joint arm exoskeleton. Eighteen severely affected chronic stroke patients were assisted by a gravity-compensating, seven-degree-of-freedom exoskeleton which was attached to the paretic arm for performing reach-to-grasp exercises resembling activities of daily living in a virtual environment. During the exercises, adaptive electrical stimulation was applied to seven different muscles of the upper extremity in a performance-dependent way to enhance the task-oriented movement trajectory. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. Closed-loop neuromuscular stimulation could be well integrated into the exoskeleton-based training, and increased the task-related range of motion (p = 0.0004) and movement velocity (p = 0.015), while preserving accuracy. The highest relative stimulation intensity was required to facilitate the grasping function. The facilitated range of motion correlated with the upper extremity Fugl-Meyer Assessment score of the patients (p = 0.028). Combining adaptive multi-channel neuromuscular stimulation with antigravity assistance amplifies the residual motor capabilities of severely affected stroke patients during rehabilitation exercises and may thus provide a customized training environment for patient-tailored support while preserving the participants' engagement. PMID:27445658

  13. Role of chloride channel inhibitors in oxidative stress-induced lens epithelial cell apoptosis%氯通道阻断剂对氧化应激诱导晶状体上皮细胞凋亡影响

    Institute of Scientific and Technical Information of China (English)

    庄晓东; 陈水花; 翁景宁

    2014-01-01

    Objective To observe the effect of chloride channels in cell damage induced by oxidative stress and to probe into its possible mechanisms.Methods 500 μmol/L tert-butyl hydroperoxide (t-BHP) was used to induce HLE B-3 cells apoptosis,the cells treated by only t-BHP were used as t-BHP-induced group,and the cells cultured by regular method were used as control group,chloride channel blockers (NPPB or DIDS) with the concentrations of 5,100 and 200 μmol/L were added into the medium for 12h respectively and with or without 500 μmol/L t-BHP-induced the cells at the same time to induce the apoptosis in experimental groups.MTT method was used to observe the cell viability.Apoptosis was measured via the Annexin V-FITC and PI staining,the intracellular free Ca2+ concentration was determined by Fluo-3 fluorometry.AO/EB double fluorescent staining was observed under the fluorescent microscope,and the cells were collected respectively after different treatments for measuring MDA level and SOD with the corresponding detection kit according to the manufactures instructions.Results Compared with t-BHP-induced group,apoptosis rate and the intracellular free Ca2+ concentration in culture medium decreased after the treatment of NPPB or DIDS (100 and 200μmol/L),cell viability in these group were significantly higher than ones of t-BHP-induced group (P <0.01).Chloride channel blockers relieved cell injury caused by t-BHP,MDA content were lower than those in t-BHP-induced group (P <0.01),and SOD activity and ATP content were higher than that in t-BHP-induced group (P <0.01).Conclusions Blockage of chloride channels by DIDS and NPPB rescued HLE B-3 cells from t-BHP-induced apoptosis,the mechanism might be related to inhibiting the calcium overload and improve the imbalance of redox homeostasis.%目的 观察氯通道阻断剂5-硝基-2 (3-苯丙胺)苯甲酸(NPPB)和二异硫氰基芪-2,2’-二磺酸(DIDS)对氧化应激诱导的晶状体上皮细胞(HLE-B3)凋亡的影响,初

  14. Cystic fibrosis transmembrane conductance regulator: a chloride channel gated by ATP binding and hydrolysis%囊性纤维化跨膜电导调节体:ATP结合和水解门控Cl-通道

    Institute of Scientific and Technical Information of China (English)

    BOMPADRE; Silvia; G; HWANG; Tzyh-Chang

    2007-01-01

    囊性纤维化跨膜电导调节体(cystic fibrosis transmembrane conductance regulator,CFTR)是一种Cl-通道,属于ATP结合(ATP-binding cassette,ABC)转运体超家族.CFTR功能缺陷是高加索人种中普遍存在的致死性常染色体隐性遗传疾病囊性纤维化(cystic fibrosis,CF)发生的主要原因.这种疾病患者各组织上皮细胞内Cl-转运失调.目前,与CF相关的不同突变超过1 400种.CFTR调节(regulatory,R)域负责调控,核苷酸结合域(nucleotide-binding domains,NBDs)NBD1和NBD2负责ATP结合和水解门控.近期研究发现CFTR的NBDs与其它ABC蛋白一样可以二聚化.二聚化过程中,NBD1和NBD2首-尾相连,一个NBD上的WalkerA和B模块与另一个NBD提供的标签序列(signature sequence)形成ATP结合袋(ATP-binding pockets,ABPs)ABP1和ABP2.ABPs中与ATP结合相关的氨基酸突变实验揭示,ABP1和ABP2在CFTR的ATP依赖门控中发挥不同作用.ABP2由NBD2上的Walk A和B模块与NBD1提供的标签序列形成,它与ATP结合催化通道开放,而ABP1单独与ATP结合不能促进通道开放,只能稳定通道构象.有一些CFTR突变相关疾病的特征就是门控失调,进一步深入研究CFTR的NBD1和NBD2如何通过相互作用而达到通道门控,将为药理学研究提供更多所需的机制信息,有利于为CF治疗的药物设计铺平道路.%The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1

  15. Role of Mitochondria-rich Cells for Passive Chloride Transport, discussion of Ussing's Contribution to Our Understanding of Shunt Pathways in Epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Kristensen, Poul; Nedergaard, Signe Nielsen;

    2001-01-01

    Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport......Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport...

  16. Intracellular chloride concentration of the mouse vomeronasal neuron

    OpenAIRE

    Kim, Sangseong; Ma, Limei; Unruh, Jay; McKinney, Sean; Yu, C. Ron

    2015-01-01

    Background The vomeronasal organ (VNO) is specialized in detecting pheromone and heterospecific cues in the environment. Recent studies demonstrate the involvement of multiple ion channels in VNO signal transduction, including the calcium-activated chloride channels (CACCs). Opening of CACCs appears to result in activation of VNO neuron through outflow of Cl− ions. However, the intracellular Cl− concentration remains undetermined. Results We used the chloride ion quenching dye, MQAE, to measu...

  17. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents the state-of-the art: an analytical model which describes chloride profiles in concrete as function of depth and...... makes physical sense for the design engineer, i.e. the achieved chloride diffusion coefficients at 1 year and 100 years, D1 and D100 respectively, and the corresponding achieved chloride concentrations at the exposed concrete surface, C1 and C100. Data from field exposure supports the assumption of time...... dependent surface chloride concentrations and the diffusion coefficients. Model parameters for Portland cement concretes with and without silica fume and fly ash in marine atmospheric and submerged South Scandinavian environment are suggested in a companion paper based on 10 years field exposure data....

  18. Pricing Models of Closed-Loop Supply Chain and Decisions on Collecting Channel Selection%闭环供应链定价模型与回收渠道选择决策

    Institute of Scientific and Technical Information of China (English)

    洪宪培; 王宗军; 赵丹

    2012-01-01

    利用Stackelberg博弈理论考察了具有直接销售渠道和间接销售渠道的闭环供应链的定价以及制造商回收渠道的选择等问题,构建了3种不同回收渠道下的闭环供应链模型.研究发现:①当间接销售渠道销售产品的市场份额在不同范围内取值时,批发价格和直接销售渠道的销售价格呈现出不同的关系 ;②当3种回收渠道的回收成本相同时,制造商回收渠道的效率更高 ;③影响回收渠道选择的主要因素与制造商所获利润的大小有关,当3种回收渠道的回收成本相同与不同时,制造商会根据自己所获利润的大小,选取不同的回牧渠道对废旧品进行回收.%This paper studies the pricing of the closed-loop supply chain with direct and indirect distribution channel and the selection of collecting channel by Stackelberg game theory. Closed-loop supply chain models under three different collecting channels are constructed. The results show: (1) The wholesale price and the selling price in direct distribution channel exhibit different relationships, when the choice of the number in certain range with market share of indirect distribution channel;(2) The efficiency of the manufacturer's collecting channel is higher when the collecting cost are the same in three collecting channels; (3)The main factor that influence the selection of the collecting channel is relevant to the manufacturer' s profit. According to the condition of the collecting cost under three collecting channels, the manufacturer selects different collecting channel deciding on its profit.

  19. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents experimentally based design parameters for Portland cement concretes with and without silica fume and fly ash in...... marine atmospheric and submersed South Scandinavian environment. The design parameters are based on sequential measurements of 86 chloride profiles taken over ten years from 13 different types of concrete. The design parameters provide the input for an analytical model for chloride profiles as function...

  20. Antidepressants and seizure-interactions at the GABA-receptor chloride-ionophore complex

    International Nuclear Information System (INIS)

    Convulsive seizures are a potential side effect of antidepressant drug treatment and can be produced by all classes of antidepressants. It is also know that some convulsant and anticonvulsant drug actions are mediated by the GABA-receptor chloride-ionophore complex. Drugs acting at this complex appear to induce convulsions by inhibiting chloride conductance through the associated chloride channel. Using the method of GABA-stimulated 36Cl-uptake by rat cerebral cortical vesicles, we show that some antidepressant drugs can inhibit the GABA-receptor chloride uptake, and that the degree of chloride channel inhibition by these drugs correlates with the frequency of convulsive seizures induced by them

  1. Chloride regulates afferent arteriolar contraction in response to depolarization

    DEFF Research Database (Denmark)

    Hansen, P B; Jensen, B L; Skott, O

    1998-01-01

    afferent arterioles. In 70% of vessels examined, K+-induced contraction was abolished by acute substitution of bath chloride. Consecutive addition of Cl- (30, 60, 80, 100, 110, and 117 mmol/L) restored the sensitivity to K+, and half-maximal response was observed at 82 mmol/L chloride. The calcium channel...... results show that K+-induced contraction of smooth muscle cells in the afferent arteriole is highly sensitive to chloride, whereas neurotransmitter release and ensuing contraction is not dependent on chloride. Thus, there are different activation pathways for depolarizing vasoconstrictors and for the......-Renal vascular reactivity is influenced by the level of dietary salt intake. Recent in vitro data suggest that afferent arteriolar contractility is modulated by extracellular chloride. In the present study, we assessed the influence of chloride on K+-induced contraction in isolated perfused rabbit...

  2. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    Prediction of chloride ingress into concrete is an important part of durability design of reinforced concrete structures exposed to chloride containing environment. This paper presents experimentally based design parameters for Portland cement concretes with and without silica fume and fly ash in...

  3. Chloride ingress prediction

    DEFF Research Database (Denmark)

    Frederiksen, Jens Mejer; Geiker, Mette Rica

    2008-01-01

    makes physical sense for the design engineer, i.e. the achieved chloride diffusion coefficients at 1 year and 100 years, D1 and D100 respectively, and the corresponding achieved chloride concentrations at the exposed concrete surface, C1 and C100. Data from field exposure supports the assumption of time...... dependent surface chloride concentrations and the diffusion coefficients. Model parameters for Portland cement concretes with and without silica fume and fly ash in marine atmospheric and submerged South Scandinavian environment are suggested in a companion paper based on 10 years field exposure data....

  4. Tarantula Huwentoxin-IV Inhibits Neuronal Sodium Channels by Binding to Receptor Site 4 and Trapping the Domain II Voltage Sensor in the Closed Configuration*S⃞

    OpenAIRE

    Xiao, Yucheng; Bingham, Jon-Paul; Zhu, Weiguo; Moczydlowski, Edward; Liang, Songping; Cummins, Theodore R.

    2008-01-01

    Peptide toxins with high affinity, divergent pharmacological functions, and isoform-specific selectivity are powerful tools for investigating the structure-function relationships of voltage-gated sodium channels (VGSCs). Although a number of interesting inhibitors have been reported from tarantula venoms, little is known about the mechanism for their interaction with VGSCs. We show that huwentoxin-IV (HWTX-IV), a 35-residue peptide from tarantula Ornithoctonus huwena v...

  5. Male germ cells and photoreceptors, both dependent on close cell-cell interactions, degenerate upon ClC-2 Cl(-) channel disruption.

    Science.gov (United States)

    Bösl, M R; Stein, V; Hübner, C; Zdebik, A A; Jordt, S E; Mukhopadhyay, A K; Davidoff, M S; Holstein, A F; Jentsch, T J

    2001-03-15

    The functions of some CLC Cl(-) channels are evident from human diseases that result from their mutations, but the role of the broadly expressed ClC-2 Cl(-) channel is less clear. Several important functions have been attributed to ClC-2, but contrary to these expectations ClC-2-deficient mice lacked overt abnormalities except for a severe degeneration of the retina and the testes, which led to selective male infertility. Seminiferous tubules did not develop lumina and germ cells failed to complete meiosis. Beginning around puberty there was a massive death of primary spermatocytes and later also of spermatogonia. Tubules were filled with abnormal Sertoli cells, which normally express ClC-2 in patches adjacent to germ cells. In the retina, photoreceptors lacked normal outer segments and degenerated between days P10 and P30. The current across the retinal pigment epithelium was severely reduced at P36. Thus, ClC-2 disruption entails the death of two cell types which depend on supporting cells that form the blood-testes and blood-retina barriers. We propose that ClC-2 is crucial for controlling the ionic environment of these cells. PMID:11250895

  6. The Effect of Channel Structures on Third-party Collecting Closed-loop Supply Chain%渠道结构对第三方负责回收闭环供应链的影响

    Institute of Scientific and Technical Information of China (English)

    聂佳佳

    2012-01-01

    Reverse logistics (e. g. product remanufacturing or recycling) practices can not only reduce the natural resources needed and the waste produced, but also help reduce the environmental burden. It is not unusual to see in practice the used-product collection activity contracted by a manufacturer to a third party, who is engaged only in the collection of the used products from the market. For example, in the automobile industry, used-product collection activities for the original equipment manufacturers are handled by some independent third parties. Recently, in the United States the "big three" auto manufacturers started to invest in joint research and remanufacturing partnerships with dismantling centers to benefit from their experiences and economics of scale. With the independent third parties joining the closed-loop supply chain, it becomes more difficult to study the closed-loop supply chain for of the increasing number supply chain members. In the third-party collecting closed-loop supply chain, there are several channels structures including no strategic alliance, strategic alliance between the retailer and the manufacturer, strategic alliance between the retailer and the third-party and strategic alliance between the manufacturer and the third-party. In this research, the aim is to examine the effect of these channel structures on the performance of members in a third-party collecting closed-loop supply chain. First, this paper adopts the game theory to develop four models of closed-loop supply chain. Second, the optimal retail prices, wholesale prices, return rates and profits of these models are derived. Third, these four models are compared with each other. Fourth, the effect of system parameters on the performance of members is researched with numerical simulation and some new findings are revealed. This study shows five interesting results. First, the retail price is the highest, the demand is the least and return rate is the lowest in the no strategic

  7. A small synthetic molecule functions as a chloride-bicarbonate dual-transporter and induces chloride secretion in cells.

    Science.gov (United States)

    Liu, Peng-Yun; Li, Shing-To; Shen, Fang-Fang; Ko, Wing-Hung; Yao, Xiao-Qiang; Yang, Dan

    2016-05-31

    A C2 symmetric small molecule composed of l-phenylalanine and isophthalamide was found to function as a Cl(-)/HCO3(-) dual transporter and self-assemble into chloride channels. In Ussing-chamber based short-circuit current measurements, this molecule elicited chloride-dependent short-circuit current (Isc) increase in both Calu-3 cell and CFBE41o-cell (with F508del mutant CFTR) monolayers. PMID:27188496

  8. Mass transport in aqueous zinc chloride-potassium chloride electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Leaist, D.G.

    1986-09-01

    Conductimetric and diaphragm cell techniques have been used to measure ternary diffusion coefficients for aqueous zinc chloride-potassium chloride solutions at 25/sup 0/C. At low concentrations where Zn/sup 2 +/ is the major zinc-transporting species, the diffusion-induced electric field along zinc chloride concentration gradients drives large co-current flows of potassium chloride. In concentrated solutions where a large proportion of zinc diffusses as anionic ZnCl/sub 3//sup -/ and ZnCl/sub 4//sup 2 -/ complexes, flow of zinc chloride generates counterflow of potassium chloride. If a sharp zinc chloride is formed in an otherwise uniform solution of potassium chloride, coupled diffusion can concentrate potassium ions within the diffusion boundary. Equations are developed to predict multicomponent transport coefficients for zinc chloride in supporting electrolytes.

  9. Chloride removal from vitrification offgas

    International Nuclear Information System (INIS)

    This study identified and investigated techniques of selectively purging chlorides from the low-level waste (LLW) vitrification process with the purge stream acceptable for burial on the Hanford Site. Chlorides will be present in high concentration in several individual feeds to the LLW Vitrification Plant. The chlorides are highly volatile in combustion type melters and are readily absorbed by wet scrubbing of the melter offgas. The Tank Waste Remediation System (TWRS) process flow sheets show that the resulting chloride rich scrub solution is recycled back to the melter. The chlorides must be purged from the recycle loop to prevent the buildup of excessively high chloride concentrations

  10. Gliadin fragments and a specific gliadin 33-mer peptide close KATP channels and induce insulin secretion in INS-1E cells and rat islets of langerhans.

    Directory of Open Access Journals (Sweden)

    Morten Dall

    Full Text Available In non-obese diabetic (NOD mice, diabetes incidence is reduced by a gluten-free diet. Gluten peptides, such as the compound gliadin, can cross the intestinal barrier and may directly affect pancreatic beta cells. We investigated the effects of enzymatically-digested gliadin in NOD mice, INS-1E cells and rat islets. Six injections of gliadin digest in 6-week-old NOD mice did not affect diabetes development, but increased weight gain (20% increase by day 100. In INS-1E cells, incubation with gliadin digest induced a dose-dependent increase in insulin secretion, up to 2.5-fold after 24 hours. A similar effect was observed in isolated rat islets (1.6-fold increase. In INS-1E cells, diazoxide reduced the stimulatory effect of gliadin digest. Additionally, gliadin digest was shown to decrease current through KATP-channels. A specific gliadin 33-mer had a similar effect, both on current and insulin secretion. Finally, INS-1E incubation with gliadin digest potentiated palmitate-induced insulin secretion by 13% compared to controls. Our data suggest that gliadin fragments may contribute to the beta-cell hyperactivity observed prior to the development of type 1 diabetes.

  11. Chloride is essential for contraction of afferent arterioles after agonists and potassium

    DEFF Research Database (Denmark)

    Jensen, B L; Ellekvist, Peter; Skøtt, O

    1997-01-01

    A depolarizing chloride efflux has been suggested to activate voltage-dependent calcium channels in renal afferent arteriolar smooth muscle cells in response to vasoconstrictors. To test this proposal, rabbit afferent arterioles were microperfused, and the contractile dose responses to...... chloride. We conclude that norepinephrine and ANG II use different mechanisms for contraction and that extracellular chloride is essential for contraction in afferent arterioles after activation of voltage-dependent calcium channels. We suggest that a chloride influx pathway is activated concomitantly with......). Reintroduction of chloride fully restored the sensitivity to norepinephrine. Contractions after ANG II and potassium were totally abolished in the absence of chloride (n = 6). In additional experiments (n = 7), the arteriolar contraction to 100 mM potassium was abolished only 1 min after removal of extracellular...

  12. [Degradation of succinylcholine chloride].

    Science.gov (United States)

    Németh, G; Török, I; Paál, T

    1993-05-01

    Quantitative thin-layer chormatographic method has been developed for the investigation of the degradation of injection formulations containing succinylcholinium chloride. The method is based on the denistometric determination of the main degradation product, choline at 430 nm after visualization with iodine vapour. The stability of the injection was investigated under various storage conditions and it has been stated that considerable decomposition takes place during as short a period as one week. PMID:8362654

  13. 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...

  14. 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.

  15. Dynamic [Cl{sup -}]{sub i} measurement with chloride sensing quantum dots nanosensor in epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yuchi; Mao Hua; Wong, Lid B, E-mail: ywang@biotechplex.com [BioTechPlex Corporation, 1205 Linda Vista Drive Suite A, San Marcos, CA 92078 (United States); Cytoptics Corporation, 1205 Linda Vista Drive Suite B, San Marcos, CA 92078 (United States)

    2010-02-05

    We have synthesized a chloride sensing quantum dots (QD) nanosensor, Cl-QD, for the dynamic measurements of chloride ion concentration in the millimolar range, a sensitivity that is applicable to most physiological intracellular chloride ion concentration ([Cl{sup -}]{sub i}) measurements in epithelial cells. The Cl-QD is synthesized by conjugating an anion receptor, 1-(2-mercapto-ethyl)-3-phenyl-thiourea (MEPTU) to a water soluble CdSe/ZnS QD at an emission wavelength of 620 nm. Upon binding of chloride ions to the Cl-QD, a photo-induced electron transfer mechanism caused the fluorescence of the QD to quench. This resulted in an inversely proportional relationship between the chloride ion concentration and the fluorescence intensity of the Cl-QD. We have utilized this Cl-QD to measure [Cl{sup -}]{sub i} in T84 and CF-PAC cultured cells, with either the C1C-2 or CFTR chloride channels being manipulated by pharmacological chloride channel activators and inhibitors. Activations of C1C-2 and CFTR chloride channels in T84 by the respective lubiprostone and genistein caused predictive increases in the fluorescence of the Cl-QD, i.e., a decrease of [Cl{sup -}]{sub i}. Conversely, glibenclamide, a chloride channel inhibitor, applied to the CF-PAC cells caused a predictable decrease in the fluorescence of Cl-QD due to the increase of [Cl{sup -}]{sub i}. These are the first data in using QD-based chloride ion sensors for dynamic measurements of intracellular chloride ion concentrations in epithelial cells.

  16. Fungal colonization with Pneumocystis correlates to increasing chloride channel accessory 1 (hCLCA1 suggesting a pathway for up-regulation of airway mucus responses, in infant lungs

    Directory of Open Access Journals (Sweden)

    Francisco J. Pérez

    2014-01-01

    Full Text Available Fungal colonization with Pneumocystis is associated with increased airway mucus in infants during their primary Pneumocystis infection, and to severity of COPD in adults. The pathogenic mechanisms are under investigation. Interestingly, increased levels of hCLCA1 – a member of the calcium-sensitive chloride conductance family of proteins that drives mucus hypersecretion – have been associated with increased mucus production in patients diagnosed with COPD and in immunocompetent rodents with Pneumocystis infection. Pneumocystis is highly prevalent in infants; therefore, the contribution of Pneumocystis to hCLCA1 expression was examined in autopsied infant lungs. Respiratory viruses that may potentially increase mucus, were also examined. hCLCA1 expression was measured using actin-normalized Western-blot, and the burden of Pneumocystis organisms was quantified by qPCR in 55 autopsied lungs from apparently healthy infants who died in the community. Respiratory viruses were diagnosed using RT-PCR for RSV, metapneumovirus, influenza, and parainfluenza viruses; and by PCR for adenovirus. hCLCA1 levels in virus positive samples were comparable to those in virus-negative samples. An association between Pneumocystis and increased hCLCA1 expression was documented (P=0.028. Additionally, increasing Pneumocystis burden correlated with increasing hCLCA1 protein expression levels (P=0.017. Results strengthen the evidence of Pneumocystis-associated up-regulation of mucus-related airway responses in infant lungs. Further characterization of this immunocompetent host-Pneumocystis-interaction, including assessment of potential clinical significance, is warranted.

  17. Closed-shell interaction in silver and gold chlorides

    OpenAIRE

    Doll, Klaus; Pyykkoe, Pekka; Stoll, Hermann

    1998-01-01

    Hartree-Fock and coupled-cluster calculations have been performed for cubic AgCl and for AuCl having a cubic or the observed structure with space group I4_1/amd. Cohesive energies and lattice constants are in excellent agreement with experiment for AgCl; for AuCl we find good agreement, and the experimental structure is correctly predicted to be lower in energy than the cubic one. Electron-correlation effects on lattice constants are very large, of up to 0.8 \\AA for cubic AuCl. We especially ...

  18. Valyl benzyl ester chloride

    Directory of Open Access Journals (Sweden)

    Grzegorz Dutkiewicz

    2010-02-01

    Full Text Available In the title compound (systematic name: 1-benzyloxy-3-methyl-1-oxobutan-2-aminium chloride, C12H18NO2+·Cl−, the ester group is approximately planar, with a maximum deviation of 0.040 (2 Å from the least-squares plane, and makes a dihedral angle of 28.92 (16° with the phenyl ring. The crystal structure is organized by N—H...Cl hydrogen bonds which join the two components into a chain along the b axis. Pairs of chains arranged antiparallel are interconnected by further N—H...Cl hydrogen bonds, forming eight-membered rings. Similar packing modes have been observed in a number of amino acid ester halides with a short unit-cell parameter of ca 5.5 Å along the direction in which the chains run.

  19. Reconciling the Krogh and Ussing interpretations of epithelial chloride transport - presenting a novel hypothesis for the physiological significance of the passive cellular chloride uptake.

    Science.gov (United States)

    Larsen, Erik Hviid

    2011-07-01

    In 1937, August Krogh discovered a powerful active Cl(-) uptake mechanism in frog skin. After WWII, Hans Ussing continued the studies on the isolated skin and discovered the passive nature of the chloride uptake. The review concludes that the two modes of transport are associated with a minority cell type denoted as the γ-type mitochondria-rich (MR) cell, which is highly specialized for epithelial Cl(-) uptake whether the frog is in the pond of low [NaCl] or the skin is isolated and studied by Ussing chamber technique. One type of apical Cl(-) channels of the γ-MR cell is activated by binding of Cl(-) to an external binding site and by membrane depolarization. This results in a tight coupling of the uptake of Na(+) by principal cells and Cl(-) by MR cells. Another type of Cl(-) channels (probably CFTR) is involved in isotonic fluid uptake. It is suggested that the Cl(-) channels serve passive uptake of Cl(-) from the thin epidermal film of fluid produced by mucosal glands. The hypothesis is evaluated by discussing the turnover of water and ions of the epidermal surface fluid under terrestrial conditions. The apical Cl(-) channels close when the electrodiffusion force is outwardly directed as it is when the animal is in the pond. With the passive fluxes eliminated, the Cl(-) flux is governed by active transport and evidence is discussed that this is brought about by an exchange of cellular HCO(3) (-) with Cl(-) of the outside bath driven by an apical H(+) V-ATPase. PMID:21288306

  20. Sodium chloride, potassium chloride, and virulence in Listeria monocytogenes.

    OpenAIRE

    MYERS, E. R.; Dallmier, A W; Martin, S E

    1993-01-01

    Virulence, as determined in a mouse model, and the virulence factor activities of catalase, superoxide dismutase, and listeriolysin O were examined in a parental strain (10403S) and in a nonhemolytic mutant strain (DP-L224) of Listeria monocytogenes. The cells were propagated in media containing various concentrations of sodium chloride or potassium chloride. Strains 10403S and DP-L224 exhibited significant increases in catalase activity and listeriolysin O activity when grown in medium conta...

  1. Contribution on creep polygonization study in crystals. Creep of single crystalline silver chloride and sodium chloride

    International Nuclear Information System (INIS)

    Subgrain formation and their influence on plastic behavior of materials has been studied in the case of single crystals of silver chloride and sodium chloride crept at high temperature (T > 0.5 Tmelting). It is shown that the creep rate ε is a function of the mean subgrain diameter d. For secondary creep ε ∝ dk with k = 2 for NaCl and AgCl. During secondary creep, the substructure changes continuously: sub-boundaries migrate and sub-grains rotate. We find that sub-boundaries migration accounts for 35 pc of the total strain and that subgrain misorientation θ increases linearly with strain ε: θ ∝ 0.14 ε. The stability of permanent creep seems related to the power that the substructure is able to dissipate. The possible subgrain formation mechanisms are examined. It is shown that subgrain formation is closely related to the geometrical conditions of deformation and to the heterogeneities of this later. (author)

  2. 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.

  3. Formation of a Chloride-conducting State in the Maltose ATP-binding Cassette (ABC) Transporter.

    Science.gov (United States)

    Carlson, Michael L; Bao, Huan; Duong, Franck

    2016-06-01

    ATP-binding cassette transporters use an alternating access mechanism to move substrates across cellular membranes. This mode of transport ensures the selective passage of molecules while preserving membrane impermeability. The crystal structures of MalFGK2, inward- and outward-facing, show that the transporter is sealed against ions and small molecules. It has yet to be determined whether membrane impermeability is maintained when MalFGK2 cycles between these two conformations. Through the use of a mutant that resides in intermediate conformations close to the transition state, we demonstrate that not only is chloride conductance occurring, but also to a degree large enough to compromise cell viability. Introduction of mutations in the periplasmic gate lead to the formation of a channel that is quasi-permanently open. MalFGK2 must therefore stay away from these ion-conducting conformations to preserve the membrane barrier; otherwise, a few mutations that increase access to the ion-conducting states are enough to convert an ATP-binding cassette transporter into a channel. PMID:27059961

  4. Market structures analysis of closed-loop supply chain in hybrid recycling channels%混合回收渠道下的闭环供应链市场结构分析

    Institute of Scientific and Technical Information of China (English)

    程晋石; 李帮义

    2013-01-01

    This paper researched remanufacturing closed-loop supply chain system that composed of a manufacturer which leads game, a retailer and a third-party collector followed the decision which was responsible for recycling. When a manufacturer was the leader of the game, it calculated the decision variables and profits of the closed-loop supply chain under four different market structures (M→R +T、M→R→T、M→T→R and M→C) ,then analyzed the calculated results in-depth. Finally formed the condition to avoid poor market structure ( M → C) based on repeated games. Studies show that: the recovery is lowest in the M →C market structure while the highest in the M→R + T market structure; the profits of manufacturers and supply chain is the least in the M →C market structure while the highest in the M→R + T market structure; the total supply chain profits is exactly the same in the M→ R →T and M→T→ R market structure. In the case of mixed recycling channels, the profit distribution parameter a in group C is unstable; something could make the least efficient market structure M → C not to exist for a long time.%研究了一个制造商领导市场、一个零售商和一个第三方回收商共同负责回收且跟随决策的再制造闭环供应链系统.对制造商领导博弈时的四种不同市场结构下(M→R+T、M→R→T、M→T→R和M→C)的闭环供应链的各方决策变量值以及利润值进行计算及分析,最后采用重复博弈方法对避免劣市场结构(M→C)成立的条件进行了讨论.研究表明,基于以上条件,M→C市场结构下的回收价最低,在M→R+T市场结构下最高;M→C市场结构下,制造商的利润与供应链利润最低;M→R+T市场结构下的制造商利润最高且供应链利润也最高.M→R→T和M→T→R市场结构的供应链总利润结果完全相同.集团C中的利润分配参数α具有不稳定性,使效率最低的M→C市场结构无法长期存在.

  5. Sodium and chloride levels in rainfall, mist, streamwater and groundwater at the Plynlimon catchments, mid-Wales: inferences on hydrological and chemical controls

    OpenAIRE

    Neal, C.; Kirchner, J.W.

    2000-01-01

    Variations in sodium and chloride in atmospheric inputs (rainfall and mist), stream runoff and groundwater stores are documented for the upper Severn River (Afon Hafren and Afon Hore catchments), Plynlimon, mid-Wales. The results show five salient features. Sodium and chloride concentrations are highly variable and highly correlated in rainfall and mist. The sodium-chloride relationship in rainfall has a slope close to the sodium/chloride ratio in sea-water, ...

  6. Sodium and chloride levels in rainfall, mist, streamwater and groundwater at the Plynlimon catchments, mid-Wales: inferences on hydrological and chemical controls

    OpenAIRE

    Neal, C.; Kirchner, J.W.

    2000-01-01

    Variations in sodium and chloride in atmospheric inputs (rainfall and mist), stream runoff and groundwater stores are documented for the upper Severn River (Afon Hafren and Afon Hore catchments), Plynlimon, mid-Wales. The results show five salient features. Sodium and chloride concentrations are highly variable and highly correlated in rainfall and mist. The sodium-chloride relationship in rainfall has a slope close to the sodium/chloride ratio in sea-water, and an intercept that is not si...

  7. Ions in Fluctuating Channels: Transistors Alive

    OpenAIRE

    Eisenberg, Bob

    2005-01-01

    Ion channels are proteins with a hole down the middle embedded in cell membranes. Membranes form insulating structures and the channels through them allow and control the movement of charged particles, spherical ions, mostly Na+, K+, Ca++, and Cl-. Membranes contain hundreds or thousands of types of channels, fluctuating between open conducting, and closed insulating states. Channels control an enormous range of biological function by opening and closing in response to specific stimuli using ...

  8. Chloride in vesicular trafficking and function.

    Science.gov (United States)

    Stauber, Tobias; Jentsch, Thomas J

    2013-01-01

    Luminal acidification is of pivotal importance for the physiology of the secretory and endocytic pathways and its diverse trafficking events. Acidification by the proton-pumping V-ATPase requires charge compensation by counterion currents that are commonly attributed to chloride. The molecular identification of intracellular chloride transporters and the improvement of methodologies for measuring intraorganellar pH and chloride have facilitated the investigation of the physiology of vesicular chloride transport. New data question the requirement of chloride for pH regulation of various organelles and furthermore ascribe functions to chloride that are beyond merely electrically shunting the proton pump. This review surveys the currently established and proposed intracellular chloride transporters and gives an overview of membrane-trafficking steps that are affected by the perturbation of chloride transport. Finally, potential mechanisms of membrane-trafficking modulation by chloride are discussed and put into the context of organellar ion homeostasis in general. PMID:23092411

  9. Stability of succinylcholine chloride injection.

    Science.gov (United States)

    Schmutz, C W; Mühlebach, S F

    1991-03-01

    The stability of succinylcholine chloride injection prepared by a hospital pharmacy was studied under a wide variety of conditions. Batches of succinylcholine chloride injection 10 mg/mL containing sodium chloride, methyl-4-hydroxybenzoate, hydrochloric acid, and water were prepared. Samples were tested for the effect of initial pH (3.0 and 4.2) and sterilization (steam treatment at 100 degrees C for 30 minutes and 121 degrees C for 20 minutes) on stability after three weeks; long-term stability under refrigeration (12, 17, and 23 months of storage at 4 degrees C); and the effect of storage temperature (4-6 degrees C, 20-26 degrees C, 35 degrees C, and 70 degrees C) and light exposure at various intervals up to 12 months. Samples were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Unlike heating at 121 degrees C, heating at 100 degrees C produced no significant loss of succinylcholine chloride, independent of the initial pH. Succinylcholine chloride was hydrolyzed only minimally over 23 months if the solution was stored at 4-6 degrees C. A 10% loss of drug content occurred if solutions were kept at 20-26 degrees C for five months, at 35 degrees C for one month, or at 70 degrees C for one day. Initial degradation was slowed if the solution was protected from light. The assessments by TLC proved to be more sensitive than the HPLC measurements. Succinylcholine chloride injection sterilized at 100 degrees C for 30 minutes can be stored for up to five months at room temperature if protected from light. The preparation is stable for at least two years under refrigeration. PMID:2028996

  10. Chloride binding of cement-based materials subjected to external chloride environment - A review

    OpenAIRE

    Yuan, Q.; Shi, C; Schutter, G. de; Audenaert, K.; Deng, D.

    2009-01-01

    This paper reviews the chloride binding of cement-based materials subjected to external chloride environments. Chloride ion exist either in the pore solution, chemically bound to the hydration products, or physically held to the surface of the hydration products. Chloride binding of cement-based material is very complicated and influenced by many factors, such as chloride concentration, cement composition, hydroxyl concentration, cation of chloride salt, temperature, supplementary cementing m...

  11. 1,5-Diaminotetrazolium chloride

    Directory of Open Access Journals (Sweden)

    Ling-Qiao Meng

    2010-04-01

    Full Text Available The title compound, CH5N6+·Cl−, crystallized with two indepedent 1,5-diaminotetrazolium cations and two independent chloride anions in the asymmetric unit. In the crystal, there are a number of N—H...Cl hydrogen-bonding interactions, which generate a three-dimensional network.

  12. Partial replacement of sodium chloride in Italian salami and the influence on the sensory properties and texture

    Directory of Open Access Journals (Sweden)

    Claudia Fieira

    2015-05-01

    Full Text Available Cured meat products, such as Italian salami, exhibit high levels of sodium from NaCl, added to ensure flavor and texture. Studies indicates a close relationship between the consumption of these products and hypertension and cardiovascular diseases. The objective of this study was to evaluate the effect of partial replacement of sodium chloride by potassium chloride, magnesium chloride, and calcium chloride on the texture and sensory attributes of Italian salami and to quantify the levels of minerals in the finished product. Four formulations were prepared: without a starter culture (F1; with a starter culture (F2; partial replacement of 60% sodium chloride by  potassium chloride (F3; and partial replacement of sodium chloride by a mixture containing potassium chloride,  magnesium chloride, and calcium chloride (F4. Analyses of Na+, K+, Ca+2 and Mg+2 contents, texture profile and sensory attributes (acceptance test were carried out. Formulations F1, F2, F3 and F4 presented levels of Na+ 0.53, 0.44, 0.36 and 0.30, respectively. The formulations presented a reduction in the sodium chloride content over 25%, thus complying with the requirements of the current legislation. The addition of these salts affected certain important sensory attributes, such as flavor and global impression, and increased hardness and chewiness values.

  13. Influence of chloride ions on actinide chemistry. Effects of radiolysis and temperature

    International Nuclear Information System (INIS)

    This research thesis addresses the chemistry of radionuclides in natural waters, an issue which is related to the management of long life radioactive wastes. Chloride ions are the most concentrated ions but their weak complexing power explains the fact that they are often neglected in speciation calculations. The objective of this research is to identify the influence of chloride ions on transuranium elements (Np, Pu and Am). Their influence is investigated with respect to chemical conditions close to that of underground waters and for concentrated media related to storage conditions in saline media. The author discusses media-related corrections applied to thermodynamic functions, reports a bibliographic study on the stability of actinide chloride complexes, reports a spectrophotometric investigation of complexation by chlorides, and reports the study of the influence of chlorides in a carbonate medium (solubility of americium at different temperatures, and notably at room temperature)

  14. Hematologic depression following therapy with strontium-89 chloride

    International Nuclear Information System (INIS)

    Initial clinical trials using strontium-89 (Sr-89) chloride for the treatment of painful skeletal metastases have observed minimal or no hematological depression secondary to the radiostrontium. A patient with marked bone marrow depression temporally related to the administration of the Sr-89 is reported, and the need for close hematological monitoring is emphasized. Bone marrow tumor replacement may predispose patients to marrow depression from radiostrontium, and such patients should be treated with caution

  15. Progress of Carbonation in Chloride Contaminated Concretes

    OpenAIRE

    Wang, Yaocheng; Basheer, P.A.M.; Nanukuttan, S; Bai, Y.

    2016-01-01

    Concretes used in marine environment are generally under the cyclic effect of CO2 and chloride ions (Cl-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate ...

  16. Chloride sublimation of gold-arsenic concentrates

    International Nuclear Information System (INIS)

    Present article is devoted to chloride sublimation of gold-arsenic concentrates. The results of studies of chloride sublimation of gold-arsenic comprising concentrates of Chore deposit of Tajikistan are considered. It is found that by application sodium chloride for gold-arsenic comprising concentrates it is possible to extract gold and silver from flotation concentrates.

  17. 21 CFR 582.5446 - Manganese chloride.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese chloride. 582.5446 Section 582.5446 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5446 Manganese chloride. (a) Product. Manganese chloride. (b) Conditions of use....

  18. The open-close mechanism of M2 channel protein in influenza A virus: A computational study on the hydrogen bonds and cation-π interactions among His37 and Trp41

    Institute of Scientific and Technical Information of China (English)

    CHENG JiaGao; ZHU WeiLiang; WANG YanLi; YAN XiuHua; LI Zhong; TANG Yun; JIANG HuaLiang

    2008-01-01

    The M2 protein from influenza A virus is a tetrameric ion channel. It was reported that the permeation of the ion channel is correlated with the hydrogen bond network among His37 residues and the cation-π interactions between His37 and Trp41. In the present study, the hydrogen bonding network of 4-methyl-imidazoles was built to mimic the hydrogen bonds between His37 residues, and the cation-π interactions between 4-methyl-imidazolium and indole systems were selected to represent the interac-tions between His37 and Trp41. Then, quantum chemistry calculations at the MP2/6-311G** level were carried out to explore the properties of the hydrogen bonds and the cation-π interactions. The calculation results indicate that the binding strength of the N--H…N hydrogen bond between imidazole rings is up to -6.22 kcal·mol-1, and the binding strength of the strongest cation-π interaction is up to -18.8 kcal·mol-1 (T-shaped interaction) or -12.3 kcal·mol-1 (parallel stacking interaction). Thus, the calculated binding energies indicate that it is possible to control the permeation of the M2 ion channel through the hydrogen bond network and the cation-π interactions by altering the pH values.

  19. The open-close mechanism of M2 channel protein in influenza A virus:A computational study on the hydrogen bonds and cation-π interactions among His37 and Trp41

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The M2 protein from influenza A virus is a tetrameric ion channel. It was reported that the permeation of the ion channel is correlated with the hydrogen bond network among His37 residues and the cation-π interactions between His37 and Trp41. In the present study,the hydrogen bonding network of 4-methyl-imidazoles was built to mimic the hydrogen bonds between His37 residues,and the cation-π interactions between 4-methyl-imidazolium and indole systems were selected to represent the interac-tions between His37 and Trp41. Then,quantum chemistry calculations at the MP2/6-311G level were carried out to explore the properties of the hydrogen bonds and the cation-π interactions. The calcula-tion results indicate that the binding strength of the N-H···N hydrogen bond between imidazole rings is up to -6.22 kcal·mol-1,and the binding strength of the strongest cation-π interaction is up to -18.8 kcal·mol-1(T-shaped interaction) or -12.3 kcal·mol-1(parallel stacking interaction). Thus,the calcu-lated binding energies indicate that it is possible to control the permeation of the M2 ion channel through the hydrogen bond network and the cation-π interactions by altering the pH values.

  20. Decay channels and charmonium mass-shifts

    CERN Document Server

    Pennington, Michael R

    2007-01-01

    The discovery in the last few years of the $X, Y$ and $Z$ states of the extended charmonium family has highlighted the importance of the closeness of decay channels to an understanding of these mesons. We aid this debate by illustrating a simple calculational procedure for including the effect of open and nearby closed channels.

  1. 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...

  2. Crystal structure of Halobacterium salinarum halorhodopsin with a partially depopulated primary chloride-binding site.

    Science.gov (United States)

    Schreiner, Madeleine; Schlesinger, Ramona; Heberle, Joachim; Niemann, Hartmut H

    2016-09-01

    The transmembrane pump halorhodopsin in halophilic archaea translocates chloride ions from the extracellular to the cytoplasmic side upon illumination. In the ground state a tightly bound chloride ion occupies the primary chloride-binding site (CBS I) close to the protonated Schiff base that links the retinal chromophore to the protein. The light-triggered trans-cis isomerization of retinal causes structural changes in the protein associated with movement of the chloride ion. In reverse, chemical depletion of CBS I in Natronomonas pharaonis halorhodopsin (NpHR) through deprotonation of the Schiff base results in conformational changes of the protein: a state thought to mimic late stages of the photocycle. Here, crystals of Halobacterium salinarum halorhodopsin (HsHR) were soaked at high pH to provoke deprotonation of the Schiff base and loss of chloride. The crystals changed colour from purple to yellow and the occupancy of CBS I was reduced from 1 to about 0.5. In contrast to NpHR, this chloride depletion did not cause substantial conformational changes in the protein. Nevertheless, two observations indicate that chloride depletion could eventually result in structural changes similar to those found in NpHR. Firstly, the partially chloride-depleted form of HsHR has increased normalized B factors in the region of helix C that is close to CBS I and changes its conformation in NpHR. Secondly, prolonged soaking of HsHR crystals at high pH resulted in loss of diffraction. In conclusion, the conformation of the chloride-free protein may not be compatible with this crystal form of HsHR despite a packing arrangement that hardly restrains helices E and F that presumably move during ion transport. PMID:27599860

  3. Neutron diffraction study of aluminum chloride imidazolium chloride molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, S. [Nisshin Steel Co. Ltd., Tokyo (Japan); Saboungi, M.L.; Suzuya, K. [Argonne National Lab., IL (United States); Koura, N. [Tokyo University of Science, Tokyo (Japan). Faculty of Science and Technology

    1994-02-01

    The structure of molten mixtures of (AlCl{sub 3}){sub x}(1-ethyl-3-methylimidazolium chloride){sub 1-x} was investigated by neutron diffraction techniques for x=0.46, 0.50, 0.60 and 0.67. Results derived from earlier ab initio molecular orbital (6-31G* basis set) computations for AlCl{sub 4}{sup {minus}}, Al{sub 2}Cl{sub 7}{sup {minus}}, and EMI{sup +} were used to calculate the diffraction patterns; the calculated contributions of each species are thus obtained and overall results are in good agreement with measurements.

  4. Covalently closed circular deoxyribonucleic acids in spiroplasmas.

    OpenAIRE

    Ranhand, J M; Mitchell, W. O.; Popkin, T J; Cole, R. M.

    1980-01-01

    Ten of twelve spiroplasma strains from different sources carried multiple covalently closed circular duplex deoxyribonucleic acid molecules, as shown by ethidium bromide-cesium chloride gradient centrifugation of cell lysates and examination of resulting bands by electron microscopy and agarose gel electrophoresis. Two to eight size classes per strain, comprising molecules of masses from 1 X 10(6) to 26 X 10(6), were detected. Several size classes of molecules were found in common in differen...

  5. Ultrastructural Observation of the Skin Chloride Cells of Japanese Flounder Paralichthys olivaceus and Turbot Scophthamus maximus Larvae

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The ultrastructures of skin chloride cells in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride cells were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride cells of euryhaline fish gill. They locate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying network of tubules. The degeneration of skin chloride cells is observed with development of Japanese flounder larvae. Skin chloride cells of turbot are less developmental than those of Japanese flounder in the same developmental stage.

  6. Evaluation of corrosion effect in reinforced concrete by chloride exposure

    Science.gov (United States)

    Loreto, G.; Di Benedetti, M.; Iovino, R.; Nanni, A.; Gonzalez, M. A.

    2011-04-01

    Durability is generally described as the ability of a material to maintain its physical and mechanical properties over time. In reinforced concrete (RC) structures, concrete is the ideal material to protect the steel reinforcement given its high alkalinity. In environments subjected to highly aggressive conditions, mostly due to the presence of chlorides, concrete may lose its protective characteristics and allow for accelerated ageing. Concrete degradation and steel reinforcement corrosion are phenomena closely connected. The aim of this research work is the characterization of the relationship between steel reinforcement corrosion and concrete degradation under accelerated ageing in a 3% sodium chloride solution. The method of linear polarization is used for identification of the corrosion rate of the steel bar. Additionally, the values of concrete residual strength are obtained, and correlated to both the corrosion rate and width of concrete cracks. Finally, the prediction of the concrete cover useful life is estimated.

  7. Playing with Opening and Closing of Heterocycles: Using the Cusmano-Ruccia Reaction to Develop a Novel Class of Oxadiazolothiazinones, Active as Calcium Channel Modulators and P-Glycoprotein Inhibitors

    Directory of Open Access Journals (Sweden)

    Domenico Spinelli

    2014-10-01

    Full Text Available As a result of the ring-into-ring conversion of nitrosoimidazole derivatives, we obtained a molecular scaffold that, when properly decorated, is able to decrease inotropy by blocking L-type calcium channels. Previously, we used this scaffold to develop a quantitative structure-activity relationship (QSAR model, and we used the most potent oxadiazolothiazinone as a template for ligand-based virtual screening. Here, we enlarge the diversity of chemical decorations, present the synthesis and in vitro data for 11 new derivatives, and develop a new 3D-QSAR model with recent in silico techniques. We observed a key role played by the oxadiazolone moiety: given the presence of positively charged calcium ions in the transmembrane channel protein, we hypothesize the formation of a ternary complex between the oxadiazolothiazinone, the Ca2+ ion and the protein. We have supported this hypothesis by means of pharmacophore generation and through the docking of the pharmacophore into a homology model of the protein. We also studied with docking experiments the interaction with a homology model of P-glycoprotein, which is inhibited by this series of molecules, and provided further evidence toward the relevance of this scaffold in biological interactions.

  8. 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.

  9. Synthesis of Zirconium Lower Chlorides

    International Nuclear Information System (INIS)

    This research is accurately related to the Halox concept of research reactor spent fuel element treatment.The aim of this project is to work the conditioning through selected chlorination of the element that make the spent fuel element. This research studied the physical chemistry conditions which produce formation of the lower zirconium chlorides through the reaction between metallic Zr and gaseous ZrCl4 in a silica reactor.This work focused special attention in the analysis and confrontation of the published results among the different authors in order to reveal coincidences and contradictions.Experimental section consisted in a set of synthesis with different reaction conditions and reactor design. After reaction were analyzed the products on Zr shavings and the deposit growth on wall reactor.The products were strongly dependent of reactor design. It was observed that as the distance between Zr and wall reactor increased greater was tendency to lower chlorides formation.In reactors with small distance the reaction follows other way without formation of lower chlorides.Analysis on deposit growth on reactor showed that may be formed to a mixture of SixZry intermetallics and zirconium oxides.Presence of oxygen in Zr and Zr-Si compounds on wall reactor reveals that there is an interaction between quartz and reactants.This interaction is in gaseous phase because contamination is observed in experiences where Zr was not in contact with reactor.Finally, it was made a global analysis of all experiences and a possible mechanism that interprets reaction ways is proposed

  10. The effect of verapamil and diltiazem on cardiac stimulant effect of adrenaline and calcium chloride on isolated frog heart

    Directory of Open Access Journals (Sweden)

    Lakhavat Sudhakar, Naveen Kumar T, Tadvi NA, Venkata Rao Y

    2013-04-01

    Full Text Available Background: Calcium channel blockers block voltage dependent L-type of calcium channel and thus reduce the frequency of opening of these channels in response to depolarization. The result is a marked decrease in transmembrane calcium current associated with long lasting relaxation of vascular smooth muscle, reduction in contractility in cardiac muscle, decrease in pacemaker activity in the SA node and decrease in conduction velocity in the AV node. Among Calcium channel blockers verapamil, is cardio selective, nifedipine is vascular smooth muscle selective, while diltiazem exhibits intermediate selectivity. Methods: In the present study, the effect of two Ca++ channel blocker, Verapamil and Diltiazem were compared on the isolated frog heart by using adrenaline & calcium chloride as standard on frog heart contractility. Results and conclusion: Adrenaline and calcium chloride increased the amplitude of contraction of isolated perfused frog heart. The L- type of Ca2+ channel blockers verapamil and diltiazem produced dose dependent (2mg, 4mg, 8mg, and 16mg reduction in the amplitude of contraction produced by calcium chloride in isolated perfused frog heart. There was no statistical significant difference (p > 0.05 between the inhibitory effect of diltiazem and verapamil on calcium chloride induced contraction of isolated frog heart.

  11. Cooper hydrometallurgy and extraction from chloride media

    International Nuclear Information System (INIS)

    The development of copper hydrometallurgy is presented and various processes proposed for copper recovery from sulphide concentrates are discussed. Leaching, extraction and stripping are considered, including reagents and processes. The extraction of copper from chloride solutions is discussed. Various extractants are presented and their use for copper transfer from chloride solutions to the organic phase and back to chloride and to sulphate solutions is discussed. (author) 4 refs

  12. Dechlorinating reaction of organic chlorides

    International Nuclear Information System (INIS)

    Dechlorination has been examined by the reaction between iron, aluminum powder or CaO and organic chlorides such as C2HCl3 and CH2Cl2. Progress of the reaction was analyzed with mass spectrometer. The reaction between iron and organic chloride was rapidly occurred at the temperature between 350 and 440degC in an atmosphere of argon. Above 380degC, more than 99.5% of C2HCl3 was decomposed within approximately 100 minutes. At 440degC, approximately 60% of C2HCl3 was decomposed by the reaction with aluminium powder within approximately 100 minutes. At 440degC, reaction between C2HCl3 and CaO powder were occurred rapidly in an atmosphere of argon to form CaCl2 and free carbon. Also in an atmosphere of air, nearly the same result was obtained. In this reaction, CaCl2, CO and CO2 were formed. CH2Cl2 was also decomposed by the reaction with iron at the temperature between 380 and 440degC. In the reaction, FeCl2, carbon and hydrogen were formed. CH3+ and CH4 were observed during the dechlorinating reaction of CH2Cl2. Variation in particle size of iron powder such as 100, 150 and 250 mesh did not affect the reaction rate. (author)

  13. Method of processing chloride waste

    International Nuclear Information System (INIS)

    In a method of applying molten salt electrolysis to chloride wastes discharged from a electrolytic refining step of a dry reprocessing step for spent fuels, and removed with transuranium elements of long half-decaying time, metals capable of alloying with alkali and alkaline earth metals under melting by electrolysis are used as a cathode material, and an electrolytic temperature is made higher than the melting point of salts in a molten salt electrolysis bath, to recover Li, Ca and Na as alloys with the cathode material in a first electrolysis step. Then, the electrolytic temperature is made higher than the melting point of the chloride salts remained in the bath after the electrolysis step described above by using the cathode material, to recover Ba, Rb, Sr and Cs of nuclear fission products also as alloys with the cathode material in a second electrolysis step. Accordingly, the amount of wastes formed can be reduced, and the wastes contain no heat generating nuclear fission elements. (T.M.)

  14. 具有产能约束和价格干预的闭环供应链网络双渠道均衡%CLOSED-LOOP SUPPLY CHAIN NETWORK DUAL CHANNEL EQUILIBRIUM MODEL WITH PRODUCTION CAPACITY CONSTRAINTS AND PRICE RIGIDITIES

    Institute of Scientific and Technical Information of China (English)

    周岩; 胡劲松; 赵海瑞; 逄晓敏

    2012-01-01

    A dual channel equilibrium model of a competitive closed-loop supply chain network with random demands is developed, with both physical and electronic transactions. The competitive dual channel closed-loop supply chain network is comprised by noncooperative manufacture/remanufacturing firms with production capacity constraints, distribution/recycling centers, retailers/recovery points with random market demand as well a binding price ceiling of the goods. With the help of variational inequality theory, the network structure of the closed-loop supply chain is identified and the dual channel equilibrium conditions are derived. An algorithm for solving the equilibrium pattern is designed by logarithmic-quadratic proximal prediction-correction method. Numerical examples were given to show the impact of production capacity constrains and price ceiling on the network equilibrium pattern. The results show that a shortage of the good arises when the government imposes a binding price ceiling on competitive markets, which is more serious in the existence of production capacity constraints. The profit of manufacture/remanufacturing firms, retailers/recovery points and supply chain is increased by adding a direct channel. However, the profit of distribution/recycling centers is decreased.%研究了闭环供应链网络双渠道均衡问题,其中制造/再制造工厂存在产能约束,通过分销/回收中心实体链和通过电子商务直销渠道,将其产品经由零售商/回收点销售给存在限制性价格上限的消费市场.借助变分不等式理论,建立了闭环供应链网络双渠道均衡模型,设计了求解均衡解的对数二次逼近的预测校正算法.从数值算例分析得到:消费市场中的商品会发生短缺,由于限制性价格上限的存在,当存在产能约束时情况会更为严重.另外,制造/再制造工厂加入直销渠道会增加制造/再制造工厂、零售商/回收点及闭环供应链的利润,但会减小分销/回收中心的利润.

  15. Green process to recover magnesium chloride from residue solution of potassium chloride production plant

    Institute of Scientific and Technical Information of China (English)

    Lin WANG; Yunliang HE; Yanfei WANG; Ying BAO; Jingkang WANG

    2008-01-01

    The green process to recover magnesium chlor-ide from the residue solution of a potassium chloride pro-duction plant, which comes from the leach solution of a potash mine in Laos, is designed and optimized. The res-idue solution contains magnesium chloride above 25 wt-%, potassium chloride and sodium chloride together below 5 wt-% and a few other ions such as Br-, SO2-4and Ca2+. The recovery process contains two steps: the previous impurity removal operation and the two-stage evapora-tion-cooling crystallization procedure to produce magnes-ium chloride. The crystallized impurity carnallite obtained from the first step is recycled to the potassium chloride plant to recover the potassium salt. The developed process is a zero discharge one and thus fulfills the requirements for green chemical industrial production. The produced magnesium chloride is up to industrial criteria.

  16. Suppression of adenosine-activated chloride transport by ethanol in airway epithelia.

    Directory of Open Access Journals (Sweden)

    Sammeta V Raju

    Full Text Available Alcohol abuse is associated with increased lung infections. Molecular understanding of the underlying mechanisms is not complete. Airway epithelial ion transport regulates the homeostasis of airway surface liquid, essential for airway mucosal immunity and lung host defense. Here, air-liquid interface cultures of Calu-3 epithelial cells were basolaterally exposed to physiologically relevant concentrations of ethanol (0, 25, 50 and 100 mM for 24 hours and adenosine-stimulated ion transport was measured by Ussing chamber. The ethanol exposure reduced the epithelial short-circuit currents (I(SC in a dose-dependent manner. The ion currents activated by adenosine were chloride conductance mediated by cystic fibrosis transmembrane conductance regulator (CFTR, a cAMP-activated chloride channel. Alloxazine, a specific inhibitor for A(2B adenosine receptor (A(2BAR, largely abolished the adenosine-stimulated chloride transport, suggesting that A(2BAR is a major receptor responsible for regulating the chloride transport of the cells. Ethanol significantly reduced intracellular cAMP production upon adenosine stimulation. Moreover, ethanol-suppression of the chloride secretion was able to be restored by cAMP analogs or by inhibitors to block cAMP degradation. These results imply that ethanol exposure dysregulates CFTR-mediated chloride transport in airways by suppression of adenosine-A(2BAR-cAMP signaling pathway, which might contribute to alcohol-associated lung infections.

  17. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    OpenAIRE

    H. Guan; Love, A. J.; C. T. Simmons; Makhnin, O.; A. S. Kayaalp

    2010-01-01

    Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB) method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the method. A high-resolution bulk chloride deposition map in the coastal region is thus needed. The aim of this study is to construc...

  18. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    OpenAIRE

    H. Guan; Love, A. J.; C. T. Simmons; Makhnin, O.; A. S. Kayaalp

    2010-01-01

    Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB) method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the method. A high-resolution bulk chloride deposition map in the coastal region is thus needed. The aim of this st...

  19. Flooding correlations in narrow channel

    International Nuclear Information System (INIS)

    Heat transfer in narrow gap is considered as important phenomena in severe accidents in nuclear power plants. Also in heat removal of electric chip. Critical heat flux(CHF) in narrow gap limits the maximum heat transfer rate in narrow channel. In case of closed bottom channel, flooding limited CHF occurrence is observed. Flooding correlations will be helpful to predict the CHF in closed bottom channel. In present study, flooding data for narrow channel geometry were collected and the work to recognize the effect of the span, w and gap size, s were performed. And new flooding correlations were suggested for high-aspect-ratio geometry. Also, flooding correlation was applied to flooding limited CHF data

  20. Time-resolved energy transfer from single chloride terminated nanocrystals to graphene

    CERN Document Server

    Ajayi, O A; Cotlet, M; Petrone, N; Gu, T; Wolcott, A; Gesuele, F; Hone, J; Owen, J S; Wong, C W

    2014-01-01

    We examine the time-resolved resonance energy transfer of excitons from single n-butyl amine-bound, chloride-terminated nanocrystals to two-dimensional graphene through time-correlated single photon counting. The radiative biexponential lifetime kinetics and blinking statistics of the individual surface-modified nanocrystal elucidate the non-radiative decay channels. Blinking modification as well as a 4 times reduction in spontaneous emission were observed with the short chloride and n-butylamine ligands, probing the energy transfer pathways for the development of graphene-nanocrystal nanophotonic devices.

  1. [Model of the selective calcium channel of characean algae].

    Science.gov (United States)

    Lunevskiĭ, V Z; Zherelova, O M; Aleksandrov, A A; Vinokurov, M G; Berestovskiĭ, G N

    1980-01-01

    The present work was intended to further investigate the selective filter of calcium channel on both a cell membrane and reconstructed channels. For the studies on cell membranes, an inhibitor of chloride channels was chosen (ethacrynic acid) to pass currents only through the calcium channels. On both the cells and reconstructed channels, permeability of ions of different crystal radii and valencies was investigated. The obtained results suggest that the channel represents a wide water pore with a diameter larger than 8 A into which ions go together with the nearest water shell. The values of the maximal currents are given by electrostatic interaction of the ions with the anion center of the channel. A phenomenological two-barrier model of the channel is given which describes the movement of all the ions studied. PMID:6251921

  2. Electrochemical Chloride extraction using external electrodes?

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul

    cathode. However, some unwanted side effects can occur, including alkali-silica reaction and in some cases hydrogen embrittlement. It is also suggested also to use electrochemical chloride extraction in a preventive way in constructions where chloride induced corrosion is likely to be a problem after a...

  3. Chloride binding site of neurotransmitter sodium symporters

    DEFF Research Database (Denmark)

    Kantcheva, Adriana Krassimirova; Quick, Matthias; Shi, Lei;

    2013-01-01

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs...

  4. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.; Glasser, Fred P.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements are...

  5. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.;

    1999-01-01

    modelled on Fick's law modified by a term for chloride binding. Inclusion of chloride binding significantly improves the profile shape of the modelled ingress profiles. The presence of fine aggregate and formation of interfacial transition zones at paste-aggregate boundaries does not significantly affect...

  6. Reliability-Based Planning of Chloride Measurements

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Engelund, S.

    1996-01-01

    on measurements of the chloride content obtained from the given structure. In the present paper optimal planning of measurements of the chloride content in reinforced concrete structures is considered. It is shown how optimal experimental plans can be obtained using FORM-analysis. Bayesian statistics...

  7. Properties of silver chloride track detectors

    International Nuclear Information System (INIS)

    The experiments on preparation of silver chloride track detectors and their properties are described. The results of X-ray structural analysis and data on sensitivity to charged particles and actinic light of silver chloride crystals, doped with several elements, are presented. (orig.)

  8. Opening the Shaker K+ channel with hanatoxin

    OpenAIRE

    Milescu, Mirela; Lee, Hwa C.; Bae, Chan Hyung; Kim, Jae Il; Swartz, Kenton J.

    2013-01-01

    Voltage-activated ion channels open and close in response to changes in membrane voltage, a property that is fundamental to the roles of these channels in electrical signaling. Protein toxins from venomous organisms commonly target the S1–S4 voltage-sensing domains in these channels and modify their gating properties. Studies on the interaction of hanatoxin with the Kv2.1 channel show that this tarantula toxin interacts with the S1–S4 domain and inhibits opening by stabilizing a closed state....

  9. Neural KCNQ (Kv7) channels

    OpenAIRE

    Brown, David A.; Passmore, Gayle M.

    2009-01-01

    KCNQ genes encode five Kv7 K+ channel subunits (Kv7.1–Kv7.5). Four of these (Kv7.2–Kv7.5) are expressed in the nervous system. Kv7.2 and Kv7.3 are the principal molecular components of the slow voltage-gated M-channel, which widely regulates neuronal excitability, although other subunits may contribute to M-like currents in some locations. M-channels are closed by receptors coupled to Gq such as M1 and M3 muscarinic receptors; this increases neuronal excitability and underlies some forms of c...

  10. Diffusion behavior of chloride ions in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T.; Gjoerv, O.E. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Div. of Building Materials

    1996-06-01

    In the present paper, an analysis of the diffusion behavior of chloride ions in concrete is presented. In concentrated electrolytic aqueous solutions such as seawater or that typically used in laboratory experiments, the effect of ionic interaction may significantly reduce the chemical potential and thus the driving force of the diffusing species. Because of different drift velocities of the cations and chloride ions in the solution, the lagging motion of the cations will also retard the drift velocity of the chlorides. In addition, both the electrical double layer forming on the solid surface and the chemical binding may significantly interfere with the transport of the chloride ions. As a result, the diffusion behavior of the chloride ions in concrete is a more complex and complicated transport process than what can be described by Fick`s law of diffusion.

  11. Simple chloride sensors for continuous groundwater monitoring

    DEFF Research Database (Denmark)

    Thorn, Paul; Mortensen, John

    2012-01-01

    The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used in continu......The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used...... sensor remained responsive even at low chloride concentrations, where the conductivity electrode was no longer responding to changing chloride levels. With the results, it is believed that the simple chloride sensor could be used for continuous monitoring of groundwater quality....

  12. Membrane chloride transport measured using a chloride-sensitive fluorescent probe

    International Nuclear Information System (INIS)

    Transport of chloride across cell membranes through exchange, cotransport, or conductive pathways is a subject of great biological importance. Current methods of measurement are restricted in their sensitivity, time resolution, and applicability. A new transport measurement technique has been developed on the basis of the fluorescence quenching by chloride of the dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). SPQ fluorescence quenching by chloride is rapid and sensitive, with a greater than 50% decrease in fluorescence at 10 mM chloride. SPQ fluorescence is not altered by other physiological anions or by pH and can be used to measure both neutral and conductive transport processes. The high water solubility and membrane permeability properties of SPQ make it ideal for use in both membrane vesicles and cells. Chloride transport determined with SPQ was validated by measurement of erythrocyte chloride/anion exchange and membrane vesicle chloride conductance using 35SO4 uptake

  13. Polarization and charge transfer in the hydration of chloride ions

    International Nuclear Information System (INIS)

    A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding waters in the external field of more distant waters. The ChelpG method is employed to explore the effective charges and dipoles on the chloride ions and first-shell waters. The quantum theory of atoms in molecules (QTAIM) is further utilized to examine charge transfer from the anion to surrounding water molecules. The clusters extracted from the AMOEBA simulations exhibit high probabilities of anisotropic solvation for chloride ions in bulk water. From the QTAIM analysis, 0.2 elementary charges are transferred from the ion to the first-shell water molecules. The default AMOEBA model overestimates the average dipole moment magnitude of the ion compared to the quantum mechanical value. The average magnitude of the dipole moment of the water molecules in the first shell treated at the MP2-level, with the more distant waters handled with an AMOEBA effective charge model, is 2.67 D. This value is close to the AMOEBA result for first-shell waters (2.72 D) and is slightly reduced from the bulk AMOEBA value (2.78 D). The magnitude of the dipole moment of the water molecules in the first solvation shell is most strongly affected by the local water-water interactions and hydrogen bonds with the second solvation shell, rather than by interactions with the ion.

  14. Polarization and charge transfer in the hydration of chloride ions

    Science.gov (United States)

    Zhao, Zhen; Rogers, David M.; Beck, Thomas L.

    2010-01-01

    A theoretical study of the structural and electronic properties of the chloride ion and water molecules in the first hydration shell is presented. The calculations are performed on an ensemble of configurations obtained from molecular dynamics simulations of a single chloride ion in bulk water. The simulations utilize the polarizable AMOEBA force field for trajectory generation and MP2-level calculations are performed to examine the electronic structure properties of the ions and surrounding waters in the external field of more distant waters. The ChelpG method is employed to explore the effective charges and dipoles on the chloride ions and first-shell waters. The quantum theory of atoms in molecules (QTAIM) is further utilized to examine charge transfer from the anion to surrounding water molecules. The clusters extracted from the AMOEBA simulations exhibit high probabilities of anisotropic solvation for chloride ions in bulk water. From the QTAIM analysis, 0.2 elementary charges are transferred from the ion to the first-shell water molecules. The default AMOEBA model overestimates the average dipole moment magnitude of the ion compared to the quantum mechanical value. The average magnitude of the dipole moment of the water molecules in the first shell treated at the MP2-level, with the more distant waters handled with an AMOEBA effective charge model, is 2.67 D. This value is close to the AMOEBA result for first-shell waters (2.72 D) and is slightly reduced from the bulk AMOEBA value (2.78 D). The magnitude of the dipole moment of the water molecules in the first solvation shell is most strongly affected by the local water-water interactions and hydrogen bonds with the second solvation shell, rather than by interactions with the ion.

  15. Theoretical calculation of the rotational excitation probability of the lithium chloride molecule in terahertz frequency combs

    International Nuclear Information System (INIS)

    We investigated how the pulse parameters of optical frequency combs affect the rotational excitation probability of the lithium chloride (7Li37Cl) molecule. Time evolution of the rotational population distribution was calculated by the close-coupling method. It was confirmed that the rotational excitation is restricted owing to the centrifugal distortion of the rotating molecule. (author)

  16. External control of anodic dissolution mechanisms of 100Cr6 in nitrate/chloride mixed electrolytes

    Directory of Open Access Journals (Sweden)

    ANDREAS LESCH

    2011-08-01

    Full Text Available The anodic dissolution of 100Cr6 steel in neutral electrolytes containing sodium chloride and sodium nitrate was investigated potentiodynamically and galvanodynamically with a rotating disc electrode at room temperature. The total concentration of the mixed electrolyte was 3 mol L-1 with variation of chloride/nitrate mole ratios. The potentiodynamic linear sweep voltammograms (LSVs in mixed electrolytes are similar to the LSVs in pure chloride electrolyte at lower current densities and switch to behaviour observed in pure nitrate electrolytes at higher current densities. Provided that both anions are present, it seems that the dissolution reactions at the steel anode are determined by the interface layer only. The effect of these layers on surface quality and current efficiency was also investigated in a flow channel applying galvanostatic pulses. An evidence for different dissolution mechanisms can be seen with an important influence of duty cycle and flow conditions. This allows external control of the desired dissolution mechanism in mixed electrolytes.

  17. Paradoxical Contribution of SK3 and GIRK Channels to the Activation of Mouse Vomeronasal Organ

    OpenAIRE

    Kim, Sangseong; Ma, Limei; Jensen, Kristi L.; Kim, Michelle M.; Bond, Chris T.; Adelman, John P.; Yu, C. Ron

    2012-01-01

    The vomeronasal organ (VNO) plays an essential role in intraspecies communication for terrestrial vertebrates. The ionic mechanisms of VNO activation remain unclear. We find that the calcium–activated potassium channel SK3 and G–protein activated potassium channel GIRK are part of an independent pathway for VNO activation. In slice preparations, the potassium channels attenuate inward currents carried by TRPC2 and calcium–activated chloride channels (CACCs). In intact tissue preparations, par...

  18. Chloride Transport in Undersea Concrete Tunnel

    Directory of Open Access Journals (Sweden)

    Yuanzhu Zhang

    2016-01-01

    Full Text Available Based on water penetration in unsaturated concrete of underwater tunnel, a diffusion-advection theoretical model of chloride in undersea concrete tunnel was proposed. The basic parameters including porosity, saturated hydraulic conductivity, chloride diffusion coefficient, initial water saturation, and moisture retention function of concrete specimens with two water-binder ratios were determined through lab-scale experiments. The variation of chloride concentration with pressuring time, location, solution concentration, initial saturation, hydraulic pressure, and water-binder ratio was investigated through chloride transport tests under external water pressure. In addition, the change and distribution of chloride concentration of isothermal horizontal flow were numerically analyzed using TOUGH2 software. The results show that chloride transport in unsaturated concrete under external water pressure is a combined effect of diffusion and advection instead of diffusion. Chloride concentration increased with increasing solution concentration for diffusion and increased with an increase in water pressure and a decrease in initial saturation for advection. The dominant driving force converted with time and saturation. When predicting the service life of undersea concrete tunnel, it is suggested that advection is taken into consideration; otherwise the durability tends to be unsafe.

  19. Shelf life of unrefrigerated succinylcholine chloride injection.

    Science.gov (United States)

    Boehm, J J; Dutton, D M; Poust, R I

    1984-02-01

    The shelf life of succinylcholine chloride injection at several pH values when stored at room temperature was evaluated. Solutions containing 20 mg/ml of succinylcholine chloride were stored at 25 and 40 degrees C. The reaction was studied at pH values ranging from 3.0 to 4.5. At two-week intervals, the solutions were assayed by high-pressure liquid chromatography. The initial amount of succinylcholine chloride in all samples was 100.1 +/- 2.37% of label claim. Hydrolysis of succinylcholine chloride in unbuffered solutions followed apparent zero-order kinetics. The pH range of maximum stability was found to be from 3.75 to 4.50. Succinylcholine chloride decomposed at a considerably higher rate at 40 degrees C. Allowing for the effects of pH adjustment during manufacture and degradation during shipping, losses of 7.0% and 9.0% potency can be expected after storage at 25 degrees C for four and six weeks, respectively. Succinylcholine Chloride Injection, USP, should be stored in the refrigerator; if unbuffered succinylcholine chloride injection complying with USP pH limits must be stored at room temperature, it should not be kept for longer than four weeks. PMID:6702837

  20. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    Directory of Open Access Journals (Sweden)

    H. Guan

    2010-05-01

    Full Text Available Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the method. A high-resolution bulk chloride deposition map in the coastal region is thus needed. The aim of this study is to construct a chloride deposition map in the Mount Lofty Ranges (MLR, a coastal hilly area of approximately 9000 km2 spatial extent in South Australia. We examined geographic (related to coastal distance, orographic, and atmospheric factors that may influence chloride deposition, using partial correlation and regression analyses. The results indicate that coastal distance, elevation, as well as terrain aspect and slope, appear to be significant factors controlling chloride deposition in the study area. Coastal distance accounts for 70% of spatial variability in bulk chloride deposition, with elevation, terrain aspect and slope an additional 15%. The results are incorporated into a de-trended residual kriging model (ASOADeK to produce a 1 km×1 km resolution bulk chloride deposition and concentration maps. The average uncertainty of the deposition map is about 20–30% in the western MLR, and 40–50% in the eastern MLR. The maps will form a useful basis for examining catchment chloride balance for the CMB application in the study area.

  1. Chloride substitution in sodium borohydride

    Science.gov (United States)

    Ravnsbæk, Dorthe B.; Rude, Line H.; Jensen, Torben R.

    2011-07-01

    The dissolution of sodium chloride and sodium borohydride into each other resulting in formation of solid solutions of composition Na(BH 4) 1- xCl x is studied. The dissolution reaction is facilitated by two methods: ball milling or combination of ball milling and annealing at 300 °C for three days of NaBH 4-NaCl samples in molar ratios of 0.5:0.5 and 0.75:0.25. The degree of dissolution is studied by Rietveld refinement of synchrotron radiation powder X-ray diffraction (SR-PXD) data. The results show that dissolution of 10 mol% NaCl into NaBH 4, forming Na(BH 4) 0.9Cl 0.1, takes place during ball milling. A higher degree of dissolution of NaCl in NaBH 4 is obtained by annealing resulting in solid solutions containing up to 57 mol% NaCl, i.e. Na(BH 4) 0.43Cl 0.57. In addition, annealing results in dissolution of 10-20 mol% NaBH 4 into NaCl. The mechanism of the dissolution during annealing and the decomposition pathway of the solid solutions are studied by in situ SR-PXD. Furthermore, the stability upon hydrogen release and uptake were studied by Sieverts measurements.

  2. Amperometric Sensor for Detection of Chloride Ions

    OpenAIRE

    Rene Kizek; Petr Babula; Jaromir Hubalek; Vojtech Adam; Libuse Trnkova

    2008-01-01

    Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE) and at a CPE modified with solid AgNO3, a solution of AgNO3 and/or solid silver particles. Detection limits (3 S/N) for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO3, solution of AgNO3 and/or solid silver particles, respectively. The CPE modified with silver particles is the mo...

  3. Binary Nucleation of Water and Sodium Chloride

    Energy Technology Data Exchange (ETDEWEB)

    Nemec, Thomas [Institute of Thermomechanics ASCR, Prague, Czech Republic; Marsik, Frantisek [Institute of Thermomechanics ASCR, Prague, Czech Republic; Palmer, Donald [ORNL

    2005-01-01

    Nucleation processes in the binary water-sodium chloride system are investigated in the sense of the classical nucleation theory (CNT). The CNT is modified to be able to handle the electrolytic nature of the system and is employed to investigate the acceleration of the nucleation process due to the presence of sodium chloride in the steam. This phenomenon, frequently observed in the Wilson zone of steam turbines, is called early condensation. Therefore, the nucleation rates of the water-sodium chloride mixture are of key importance in the power cycle industry.

  4. Ergodic Capacity for the SIMO Nakagami- Channel

    Directory of Open Access Journals (Sweden)

    Vagenas EfstathiosD

    2009-01-01

    Full Text Available This paper presents closed-form expressions for the ergodic channel capacity of SIMO (single-input and multiple output wireless systems operating in a Nakagami- fading channel. As the performance of SIMO channel is closely related to the diversity combining techniques, we present closed-form expressions for the capacity of maximal ratio combining (MRC, equal gain combining (EGC, selection combining (SC, and switch and stay (SSC diversity systems operating in Nakagami- fading channels. Also, the ergodic capacity of a SIMO system in a Nakagami- fading channel without any diversity technique is derived. The latter scenario is further investigated for a large amount of receive antennas. Finally, numerical results are presented for illustration.

  5. Anisotropic diffusion of spherical particles in closely confining microchannels

    CERN Document Server

    Dettmer, Simon L; Misiunas, Karolis; Keyser, Ulrich F

    2014-01-01

    We present here the measurement of the diffusivity of spherical particles closely confined by narrow microchannels. Our experiments yield a 2D map of the position-dependent diffusion coefficients parallel and perpendicular to the channel axis with a resolution down to 129 nm. The diffusivity was measured simultaneously in the channel interior, the bulk reservoirs as well as the channel entrance region. In the channel interior we found strongly anisotropic diffusion. While the perpendicular diffusion coefficient close to the confining walls decreased down to approximately 25 % of the value on the channel axis, the parallel diffusion coefficient remained constant throughout the entire channel width. In addition to the experiment, we performed finite element simulations for the diffusivity in the channel interior and found good agreement with the measurements. Our results reveal the distinctive influence of strong confinement on Brownian motion which is of significance to microfluidics as well as quantitative mo...

  6. GmCLC1 Confers Enhanced Salt Tolerance through Regulating Chloride Accumulation in Soybean.

    Science.gov (United States)

    Wei, Peipei; Wang, Longchao; Liu, Ailin; Yu, Bingjun; Lam, Hon-Ming

    2016-01-01

    The family of chloride channel proteins that mediate Cl(-) transportation play vital roles in plant nutrient supply, cellular action potential and turgor pressure adjustment, stomatal movement, hormone signal recognition and transduction, Cl(-) homeostasis, and abiotic and biotic stress tolerance. The anionic toxicity, mainly caused by chloride ions (Cl(-)), on plants under salt stress remains poorly understood. In this work, we investigated the function of soybean Cl(-)/H(+) antiporter GmCLC1 under salt stress in transgenic Arabidopsis thaliana, soybean, and yeast. We found that GmCLC1 enhanced salt tolerance in transgenic A. thaliana by reducing the Cl(-) accumulation in shoots and hence released the negative impact of salt stress on plant growth. Overexpression of GmCLC1 in the hairy roots of soybean sequestered more Cl(-) in their roots and transferred less Cl(-) to their shoots, leading to lower relative electrolyte leakage values in the roots and leaves. When either the soybean GmCLC1 or the yeast chloride transporter gene, GEF1, was transformed into the yeast gef1 mutant, and then treated with different chloride salts (MnCl2, KCl, NaCl), enhanced survival rate was observed. The result indicates that GmCLC1 and GEF1 exerted similar effects on alleviating the stress of diverse chloride salts on the yeast gef1 mutant. Together, this work suggests a protective function of GmCLC1 under Cl(-) stress. PMID:27504114

  7. Effects of lithium chloride on outward potassium currents in acutely isolated hippocampal CA1 pyramidal neurons

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaofeng; DU Huizhi; YANG Pin

    2006-01-01

    Although lithium possesses neuroprotective functions, the molecular mechanism underlying its actions has not been fully elucidated. In the present paper, the effects of lithium chloride on voltage-dependent potassium currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied using the whole-cell patch-clamp technique. Depolarizing test pulses activated two components of outward potassium currents: a rapidly activating and inactivating component, IA and a delayed component, IK. Results showed that lithium chloride increased the amplitude of IA in a concentration-dependent manner. Half enhancement concentration (EC50) was 22.80±5.45 μmol·L-1. Lithium chloride of 25 μmol·L-1 shifted the steady-state activation curve and inactivation curve of IA to more negative potentials, but mainly affected the activation kinetics. The amplitude and the activation processes of IK were not affected by lithium chloride. The effects of lithium chloride on potassium channel appear to possess neuroprotective properties by Ca2+-lowing effects modulate neuronal excitability by activating IA in rat hippocampal neurons.

  8. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    Science.gov (United States)

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting. PMID:27077530

  9. Annihilation Of Fast Channeled Positrons

    CERN Document Server

    Hunt, A W

    2000-01-01

    Energetic positrons propagating along low index directions in a crystal interact strongly with the periodic array of atoms via a process known as channeling. These channeled positrons are focused into the interstices of a crystal by a series of highly correlated small angle scattering events, thereby suppressing close nuclear collision processes and increasing interactions with valence electrons. Moreover, the positron trajectories can be manipulated to sample different spatial regions in the crystal, simply by changing the direction of the incident positron beam. As this direction deviates from that of the low index crystal direction the positron momentum transverse to this crystal direction increases, and the trajectories penetrate closer to the atomic nuclei of the crystal's atoms. Thus when observing the angular yield of close encounter events with the atomic nuclei, like wide angle Rutherford scattering, a characteristic channeling dip is obtained for positive ions and positrons traversing thin crystals[...

  10. Catastrophic event modeling. [lithium thionyl chloride batteries

    Science.gov (United States)

    Frank, H. A.

    1981-01-01

    A mathematical model for the catastrophic failures (venting or explosion of the cell) in lithium thionyl chloride batteries is presented. The phenomenology of the various processes leading to cell failure is reviewed.

  11. Single Na+ channels activated by veratridine and batrachotoxin

    OpenAIRE

    1987-01-01

    Voltage-sensitive Na+ channels from rat skeletal muscle plasma membrane vesicles were inserted into planar lipid bilayers in the presence of either of the alkaloid toxins veratridine (VT) or batrachotoxin (BTX). Both of these toxins are known to cause persistent activation of Na+ channels. With BTX as the channel activator, single channels remain open nearly all the time. Channels activated with VT open and close on a time scale of 1-10 s. Increasing the VT concentration enhances the probabil...

  12. Channel Capacity under Sub-Nyquist Nonuniform Sampling

    OpenAIRE

    Chen, Yuxin; Goldsmith, Andrea J.; Eldar, Yonina C.

    2012-01-01

    This paper investigates the effect of sub-Nyquist sampling upon the capacity of an analog channel. The channel is assumed to be a linear time-invariant Gaussian channel, where perfect channel knowledge is available at both the transmitter and the receiver. We consider a general class of right-invertible time-preserving sampling methods which include irregular nonuniform sampling, and characterize in closed form the channel capacity achievable by this class of sampling methods, under a samplin...

  13. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    OpenAIRE

    H. Guan; Love, A. J.; C. T. Simmons; A. S. Kayaalp

    2009-01-01

    Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB) method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the CMB approach. Furthermore, intensive vegetation clearance for agriculture, for example during the European settlement in many...

  14. Telomerization of Vinyl Chloride with Chloroform Initiated by Ferrous Chloride-Dimethylacetamide under Ultrasonic Conditions

    Directory of Open Access Journals (Sweden)

    Hua Qian

    2015-01-01

    Full Text Available Telomerization of vinyl chloride with chloroform was investigated using ferrous chloride-dimethylacetamide system, and 42.1% yield, more than four times the one reported before, was achieved. The addition of ultrasound further improved the reaction and yield was raised to 51.9% with trace byproducts at highly reduced reaction time and temperature. Ferrous chloride-dimethylacetamide under ultrasonic irradiation acts as a very efficient catalyst system for the 1 : 1 telomerization.

  15. Sodium, potassium and chloride status in Australian foods and diets using neutron activation analysis

    International Nuclear Information System (INIS)

    A study of the status of essential, toxic and trace elements in the foods and diets of Australian has been in progress for six years. Results for sodium, potassium and chloride levels are reported here. The average daily dietary intake of sodium and chloride exceeded the range of values recommended by the National Health and Medical Research Council for most population groups with grain and dairy products the main contributor to these high intakes. In contrast, the average daily intakes of potassium fell well within the recommended values for all age groups with intakes for adult females close to the recommended minimum figure. 9 refs., 1 tab., 2 figs

  16. Sodium, potassium and chloride status in Australian foods and diets using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.; Bowles, C.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    A study of the status of essential, toxic and trace elements in the foods and diets of Australian has been in progress for six years. Results for sodium, potassium and chloride levels are reported here. The average daily dietary intake of sodium and chloride exceeded the range of values recommended by the National Health and Medical Research Council for most population groups with grain and dairy products the main contributor to these high intakes. In contrast, the average daily intakes of potassium fell well within the recommended values for all age groups with intakes for adult females close to the recommended minimum figure. 9 refs., 1 tab., 2 figs.

  17. The kinetics of the hydrogen chloride oxidation

    Directory of Open Access Journals (Sweden)

    Gonzalez Martinez Isai

    2013-01-01

    Full Text Available Hydrogen chloride (HCl oxidation has been investigated on technical membrane electrode assemblies in a cyclone flow cell. Influence of Nafion loading, temperature and hydrogen chloride mole fraction in the gas phase has been studied. The apparent kinetic parameters like reaction order with respect to HCl, Tafel slope and activation energy have been determined from polarization data. The apparent kinetic parameters suggest that the recombination of adsorbed Cl intermediate is the rate determining step.

  18. Estimating the chloride transport in cement paste

    OpenAIRE

    Princigallo, A.

    2012-01-01

    A method was developed to measure the diffusion coefficient of chloride ions in cement paste based on an analytical solution to Fick’s 2nd law in a cylindrical coordinate system. This natural method yielded diffusivity results within as little as a month. Testing time was reduced by exploiting the three-dimensional inward flux in the specimen. In an attempt to determine the saturation concentration, dense portland cement pastes were exposed to a concentrated chloride solution. The method prov...

  19. Effect of Chloride Type on Penetration of Chloride Ions in Concrete

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The influence of chloride type on the diffusivity of chloride ions in concrete was studied by experiment. The result shows that the glectric resistance of concrete and the chloride diffusion coefficient are influenced by chloride type. For the same water/cement ratio (W/C), the diffusion coefficient D in KCl solution is larger than that in NaCl solution; however, the concrete resistance in KCl solution is smaller than that in NaCl solution. The experimental result is analyzed with theory of diffusion.

  20. The Degraded Poisson Wiretap Channel

    CERN Document Server

    Laourine, Amine

    2010-01-01

    Providing security guarantees for wireless communication is critically important for today's applications. While previous work in this area has concentrated on radio frequency (RF) channels, providing security guarantees for RF channels is inherently difficult because they are prone to rapid variations due small scale fading. Wireless optical communication, on the other hand, is inherently more secure than RF communication due to the intrinsic aspects of the signal propagation in the optical and near-optical frequency range. In this paper, secure communication over wireless optical links is examined by studying the secrecy capacity of a direct detection system. For the degraded Poisson wiretap channel, a closed-form expression of the secrecy capacity is given. A complete characterization of the general rate-equivocation region is also presented. For achievability, an optimal code is explicitly constructed by using the structured code designed by Wyner for the Poisson channel. The converse is proved in two dif...

  1. Thermosyphon boiling in vertical channels

    Science.gov (United States)

    Bar-Cohen, A.; Schweitzer, H.

    The thermal characteristics of ebullient cooling systems for VHSIC and VLSI microelectronic component thermal control are studied by experimentally and analytically investigating boiling heat transfer from a pair of flat, closely spaced, isoflux plates immersed in saturated water. A theoretical model for liquid flow rate through the channel is developed and used as a basis for correlating the rate of heat transfer from the channel walls. Experimental results for wall temperature as a function of axial location, heat flux, and plate spacing are presented. The finding that the wall superheat at constant imposed heat flux decreases as the channel is narrowed is explained with the aid of a boiling thermosiphon analysis which yields the mass flux through the channel.

  2. Swelling-Activated Anion Channels Are Essential for Volume Regulation of Mouse Thymocytes

    Directory of Open Access Journals (Sweden)

    Ravshan Z. Sabirov

    2011-12-01

    Full Text Available Channel-mediated trans-membrane chloride movement is a key process in the active cell volume regulation under osmotic stress in most cells. However, thymocytes were hypothesized to regulate their volume by activating a coupled K-Cl cotransport mechanism. Under the patch-clamp, we found that osmotic swelling activates two types of macroscopic anion conductance with different voltage-dependence and pharmacology. At the single-channel level, we identified two types of events: one corresponded to the maxi-anion channel, and the other one had characteristics of the volume-sensitive outwardly rectifying (VSOR chloride channel of intermediate conductance. A VSOR inhibitor, phloretin, significantly suppressed both macroscopic VSOR-type conductance and single-channel activity of intermediate amplitude. The maxi-anion channel activity was largely suppressed by Gd3+ ions but not by phloretin. Surprisingly, [(dihydroindenyloxy] alkanoic acid (DIOA, a known antagonist of K-Cl cotransporter, was found to significantly suppress the activity of the VSOR-type single-channel events with no effect on the maxi-anion channels at 10 μM. The regulatory volume decrease (RVD phase of cellular response to hypotonicity was mildly suppressed by Gd3+ ions and was completely abolished by phloretin suggesting a major impact of the VSOR chloride channel and modulatory role of the maxi-anion channel. The inhibitory effect of DIOA was also strong, and, most likely, it occurred via blocking the VSOR Cl− channels.

  3. 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

  4. 49 CFR 179.102-17 - Hydrogen chloride, refrigerated liquid.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen chloride, refrigerated liquid. 179.102-17...) § 179.102-17 Hydrogen chloride, refrigerated liquid. Each tank car used to transport hydrogen chloride... on or after March 16, 2009 used for the transportation of hydrogen chloride, refrigerated...

  5. 21 CFR 178.3290 - Chromic chloride complexes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chromic chloride complexes. 178.3290 Section 178... SANITIZERS Certain Adjuvants and Production Aids § 178.3290 Chromic chloride complexes. Myristo chromic chloride complex and stearato chromic chloride complex may be safely used as release agents in the...

  6. 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.

  7. A component of platypus (Ornithorhynchus anatinus) venom forms slow-kinetic cation channels.

    Science.gov (United States)

    Kourie, J I

    1999-11-01

    The lipid bilayer technique is used to examine the biophysical properties of anion and cation channels frequently formed by platypus (Ornithorhynchus anatinus) venom (OaV). The OaV-formed anion channel in 250/50 mm KCl cis/trans has a maximum conductance of 857 +/- 23 pS (n = 5) in 250/50 mm KCl cis/trans. The current-voltage relationship of this channel shows strong inward rectification. The channel activity undergoes time-dependent inactivation that can be removed by depolarizing voltage steps more positive than the reversal potential for chloride, E(Cl), (+40 mV). The reversal potential of the OaV-formed slow current activity in 250/50 mm KCl cis/trans is close to the potassium equilibrium potential (E(K)) of -40 mV. The conductance values for the slow channel are 22.5 +/- 2.6 pS and 41.38 +/- 4.2 pS in 250/50 and 750/50 mm cis/trans, respectively. The gating kinetics of the slow ion channels are voltage-dependent. The channel open probability (P(o)) is between 0.1 and 0.8 at potentials between 0 and +140 mV. The channel frequency (F(o)) increases with depolarizing voltages between 0 and +140 mV, whereas mean open time (T(o)) and mean closed time (T(c)) decrease. Ion substitution experiments of the cis solution show that the channel has conductance values of 21.47 +/- 2. 3 and 0.53 +/- 0.1 pS in 250 mm KCl and choline Cl, respectively. The amplitude of the single channel current is dependent on [K(+)](cis) and the current reversal potential (E(rev)) responds to increases in [K(+)](cis) by shifting to more negative voltages. The increase in current amplitude as a function of increasing [K(+)](cis) can be best described by a third order polynomial fit. At +140 mV, the values of the maximal single channel conductance (gamma(max)) and the concentration for half maximal gamma (K(s)) are 38.6 pS and 380 mm and decline to 15.76 pS and 250 mm at 0 mV, respectively. The ion selectivity of the channel to K(+), Na(+), Cs(+) and choline(+) was determined in ion substitution

  8. Factors influencing chloride deposition in a coastal hilly area and application to chloride deposition mapping

    Directory of Open Access Journals (Sweden)

    H. Guan

    2009-09-01

    Full Text Available Chloride is commonly used as an environmental tracer for studying water flow and solute transport in the environment. It is especially useful for estimating groundwater recharge based on the commonly used chloride mass balance (CMB method. Strong spatial variability in chloride deposition in coastal areas is one difficulty encountered in appropriately applying the CMB approach. Furthermore, intensive vegetation clearance for agriculture, for example during the European settlement in many coastal areas of Australia, may have perturbed catchment chloride balance conditions for appropriate use in CMB applications. In order to deal with these issues, a high resolution chloride deposition map in the coastal region is needed. In this study, we examined geographic, orographic, and atmospheric factors influencing chloride deposition in the Mount Lofty Ranges (MLR, a coastal hilly area of approximately 9000 km2 spatial extent in South Australia, using partial correlation and regression analyses. The results indicate that coastal distance, and terrain aspect and slope are two most significant factors controlling chloride deposition. Coastal distance accounts for 65% spatial variability in chloride deposition, with terrain aspect and slope for 8%. The deposition gradient is about 0.08 gm-2 year-1 km-1 as one progresses inland. The results are incorporated into a published de-trended residual kriging approach (ASOADeK to produce a 1 km×1 km resolution annual chloride deposition map and a bulk precipitation chloride concentration map. The average uncertainty of the deposition map is about 30% in the western MLR, and over 50% in the eastern MLR. The maps will form a very useful basis for examining catchment chloride balances for use in the CMB application in the study area.

  9. Origin of unusual sintering phenomena in compacts of chloride-derived 3Y-TZP nanopowders

    Directory of Open Access Journals (Sweden)

    Sweeney Sean M.

    2014-01-01

    Full Text Available After evaluating three alternative possibilities, the present study shows that seemingly minor amounts (at least as low as 0.06 wt% of chlorine impurities are responsible for the poor sintering behavior observed in chloride-derived 3 mol% yttria stabilized zirconia (3Y-TZP nanopowders. Models and quantitative estimates are used to explain the role of evolved HCl and ZrCl4 gases in such anomalous behaviors as reduced sintered densities for higher green densities, de-densification, improved sintering in nitrogen over oxygen, and formation of a dense shell microstructure. Two solutions to problematic residual chlorides are compared: 1 a thermal treatment composed of an extended hold at 1000°C to allow HCl gas removal before the onset of closed porosity, and 2 a chemical treatment performed by washing bisque-fired samples at room temperature using a concentrated ammonium hydroxide solution to remove chlorides. The thermal treatment was found to be superior.

  10. Amine and Titanium (IV Chloride, Boron (III Chloride or Zirconium (IV Chloride-Promoted Baylis-Hillman Reactions

    Directory of Open Access Journals (Sweden)

    Shi-Cong Cui

    2001-10-01

    Full Text Available The Baylis-Hillman reactions of various aryl aldehydes with methyl vinyl ketone at temperatures below -20oC using Lewis acids such as titanium (IV chloride, boron (III chloride or zirconium (IV chloride in the presence of a catalytic amount of selected amines used as a Lewis bases afford the chlorinated compounds 1 as the major product in very high yields. Acrylonitrile can also undergo the same reaction to give the corresponding chlorinated product in moderate yield. A plausible reaction mechanism is proposed. However, if the reaction was carried out at room temperature (ca. 20oC, then the Z-configuration of the elimination product 3, derived from 1, was formed as the major product.

  11. Mechanisms underlying KCNQ1channel cell volume sensitivity

    DEFF Research Database (Denmark)

    Hammami, Sofia

    Cells are constantly exposed to changes in cell volume during cell metabolism, nutrient uptake, cell proliferation, cell migration and salt and water transport. In order to cope with these perturbations, potassium channels in line with chloride channels have been shown to be likely contributors to...... the process of cell volume adjustments. A great diversity of potassium channels being members of either the 6TM, 4 TM or 2 TM K+ channel gene family have been shown to be strictly regulated by small, fast changes in cell volume. However, the precise mechanism underlying the K+ channel sensitivity to...... cell volume alterations is not yet fully understood. The KCNQ1 channel belonging to the voltage gated KCNQ family is considered a precise sensor of volume changes. The goal of this thesis was to elucidate the mechanism that induces cell volume sensitivity. Until now, a number of investigators have...

  12. Online Friendship Formation, Communication Channels, and Social Closeness

    Directory of Open Access Journals (Sweden)

    Ilan Talmud

    2006-03-01

    Full Text Available Studies of the quality of online social relationships are divided in their conclusions regarding the strength of social ties. Early conceptualizations described the weakness of electronic media in supporting social ties. By contrast, others have emphasized the compensating character of the Internet for specific social groups. This study investigated differences between adolescents who created online friendships and those who did not, and how far the place where a friend was met (online or face to face was related to the quality of social relationships, namely the perceived strength of social ties. Examining the dyadic friendship structure of a representative sample of Israeli adolescents, the study provides important contributions to the rapidly growing literature on online social relationships in general, and on youth networks in particular. The results support the social compensation approach to the study of online social relationship formation. The motivation for online friendship formation proved to be related to adolescents’ attempts to compensate for a lack of social support by using the Internet for communication. Furthermore, while face-to-face relationships remained highly important, for those adolescents who found in the Internet others with whom they developed intimacy, online ties were strong and meaningful. Additionally, adolescents with strong virtual ties were found to be distinctive in their social background. Our findings call for a qualification of the theoretical approach to online social ties, and imply that it is not the technology per se that obstructs or facilitates the formation of social friendship but the social embeddedness of the ties.

  13. Hydrolysis of ferric chloride in solution

    International Nuclear Information System (INIS)

    The Detox trademark process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200 degrees C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl3liquid + H2O → FeOClsolid + 2 HClgas During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOClsolid + H2O → Fe2O3solid + 2 HClgas. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way

  14. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times......Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...

  15. 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)

  16. Effects of calcium channel on 3-morpholinosydnonimine-induced rat hippocampal neuronal apoptosis

    Institute of Scientific and Technical Information of China (English)

    Quanzhong Chang; Shuling Zhang; Yuanyin Zheng; Lijuan Xu; Jinbao Yin; Shining Cai

    2011-01-01

    Previous studies have demonstrated that increased chloride channel activity plays a role in nitric oxide-induced neuronal apoptosis in the rat hippocampus.The present study investigated the effects of the broad-spectrum calcium channel blocker CdC12 on survival rate, percentage of apoptosis, and morphological changes in hippocampal neurons cultured in vitro, as well as the effects of calcium channels on neuronal apoptosis.The chloride channel blockers 4-acetamido-4'-isothiocyanatostilbene-2, 2'-disulfonic acid (SITS) or 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) increased the survival rate of 3-morpholinosydnonimine (SIN-1)-treated neurons and suppressed SIN-1-induced neuronal apoptosis.The calcium channel blocker CdC12 did not increase the survival rate of neurons and did not affect SIN-1-induced apoptosis or SITS- or DIDS-suppressed neuronal apoptosis.Results demonstrated that calcium channels did not significantly affect neuronal apoptosis.

  17. Role of Du Channel in Treating Senile Dementia

    Institute of Scientific and Technical Information of China (English)

    Lu Fan

    2006-01-01

    @@ The author believes that senile dementia is very closely related to not only deficiency of the liver and kidney, but also Eight Extra Channels, Du Channel in particular. Nourishing the liver and kidney and clearing Du Channel in the treatment can greatly enhance the therapeutic effect.

  18. 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

  19. Combining sulfate electrowinning with chloride leaching

    Science.gov (United States)

    Fletcher, A. W.; Sudderth, R. B.; Olafson, S. M.

    1991-08-01

    Although the chloride leaching of copper sulfide concentrates has proved highly efficient, electrowinning from chloride solutions presents many difficulties, notably in cell design and the handling of the powder product. Sulfate electrowinning,on the other hand, continues to improve and has played a significant part in the widespread adoption of the solvent extraction-electrowinning process for copper recovery from low-grade ores. It has been found that the two steps can be combined by introducing a novel solvent extraction process after chloride leaching. This article presents the results of laboratory tests to prove the feasibility of this approach and discusses how it can be integrated into a commercially viable flow sheet.

  20. The SecY complex forms a channel capable of ionic discrimination

    OpenAIRE

    Dalal, Kush; Duong, Franck

    2009-01-01

    Protein translocation across the bacterial membrane occurs at the SecY complex or channel. The resting SecY channel is impermeable to small molecules owing to a plug domain that creates a seal. Here, we report that a channel loosely sealed, or with a plug locked open, does not, however, lead to general membrane permeability. Instead, strong selectivity towards small monovalent anions, especially chloride, is observed. Mutations in the pore ring-structure increase both the translocation activi...

  1. Movements of native C505 during channel gating in CNGA1 channels.

    NARCIS (Netherlands)

    Nair, A.V.; Anselmi, C.; Mazzolini, M.

    2009-01-01

    We investigated conformational changes occurring in the C-linker and cyclic nucleotide-binding (CNB) domain of CNGA1 channels by analyzing the inhibition induced by thiol-specific reagents in mutant channels Q409C and A414C in the open and closed state. Cd(2+) (200 microM) inhibited irreversibly mut

  2. Studies on closed-cycle processes for hydrogen production, 1

    International Nuclear Information System (INIS)

    This report describes our studies on closed-cycle processes for hydrogen production by nuclear energy, for the period until March, 1975. Reactions of carbon dioxide were studied in our search for new processes for the thermochemical production of hydrogen. As a result, a number of new processes were constructed, studied thermodynamically and some related thermochemical experiments made preliminarily. The originated processes are composed of more than three reaction steps. By the first step, carbon monoxide is formed from the high temperature (max. 13000K) reaction between bivalent transition metal chloride and carbon dioxide. Hydrogen is formed by the second step (CO shift reaction), in which carbon monoxide reacts with steam, regenerating carbon dioxide. By the further steps, the bivalent chlorides are regenerated from oxides or higher chlorides formed in the first step. Reactions of the carbonates and chlorides were studied by the simultaneous thermogravimetry (TG) and differential thermal analysis (DTA) in the atmosphere of helium or carbon dioxide. When combined with the CO shift reaction, carbon dioxide radiolysis may be utilized to construct a closed-cycle hydrogen production process. (JPN)

  3. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  4. Hydrogenation of Tasmanian alginite in the presence of tin (II) chloride and zinc chloride

    Energy Technology Data Exchange (ETDEWEB)

    Russell, N.J.

    1981-10-01

    A Mersey River (Tasmanian) algnite concentrate was heated (3 Cmin$SUP$-$SUP$1 to temperatures of 200-480 C in a small capacity, high-pressure, single-cell differential thermal analysis, batch autoclave under nitrogen or hydrogen (initial pressure 9.8 MPa) with or without 10 wt% zinc chloride or tin (II) chloride. An organic solvent (vehicle) was not used in these experiments. Although there is an almost complete conversion of alginite to gaseous and liquid products between 425 and 450 C, the compositions of the autoclave gas samples, the yields and compositions of the hexane-soluble material derived from the autoclave products, and the optical properties of the hexane-soluble residues, reflect the experimental conditions, in particular the influence of the metal chlorides. Principal phases of hydrogen uptake by alginite occur at different temperatures in a hydrogen atmosphere depending on the presence and nature of the metal chloride. The autoclave gas compositions reveal a clear distinction between the uncatalysed and catalysed experiments. The hydrocarbon gas ratios permit a distinction to be made between catalytic (carbonium ion mechanism) reactions and thermal (free radical mechanism) reactions; at higher temperatures the latter are dominant, even in the catalysed experiments. The metal chlorides lower the organic sulphur and nitrogen contents of the hexane-soluble material; zinc chloride being more effective than tin (II) chloride. Incident light fluorescence microscopy suggests that zinc chloride and tin (II) chloride give rise to different hydrogenation reactions between 300 and 425 C. Incident light fluorescence microscopy is a most useful method of studying the petrography of alignite in the hexane-insoluble residues. (28 refs.)

  5. Effective IPTV channel management method over heterogeneous environments

    Science.gov (United States)

    Joo, Hyunchul; Lee, Dai-boong; Song, Hwangjun

    2007-09-01

    This paper presents an effective IPTV channel management method using SVC (scalable video coding) that considers concurrently both channel zapping time and network utilization. A broadcasting channel is encoded in two-layered bitstream (base-layer channel and enhancement-layer channel) to supply for heterogeneous environments. The proposed algorithm locates only a limited numbers of base-layer channels close to users to reduce the network delay part of channel zapping time and adjusts the length of GOP (group of picture) into each base-layer channel to decrease the video decoding delay part of channel zapping time, which are performed based on user's channel preference information. Finally, the experimental results are provided to show the performance of the proposed schemes.

  6. Plant Ion Channels: Gene Families, Physiology, and Functional Genomics Analyses

    Science.gov (United States)

    Ward, John M.; Mäser, Pascal; Schroeder, Julian I.

    2016-01-01

    Distinct potassium, anion, and calcium channels in the plasma membrane and vacuolar membrane of plant cells have been identified and characterized by patch clamping. Primarily owing to advances in Arabidopsis genetics and genomics, and yeast functional complementation, many of the corresponding genes have been identified. Recent advances in our understanding of ion channel genes that mediate signal transduction and ion transport are discussed here. Some plant ion channels, for example, ALMT and SLAC anion channel subunits, are unique. The majority of plant ion channel families exhibit homology to animal genes; such families include both hyperpolarization-and depolarization-activated Shaker-type potassium channels, CLC chloride transporters/channels, cyclic nucleotide–gated channels, and ionotropic glutamate receptor homologs. These plant ion channels offer unique opportunities to analyze the structural mechanisms and functions of ion channels. Here we review gene families of selected plant ion channel classes and discuss unique structure-function aspects and their physiological roles in plant cell signaling and transport. PMID:18842100

  7. Synthetic ion transporters can induce apoptosis by facilitating chloride anion transport into cells

    Science.gov (United States)

    Ko, Sung-Kyun; Kim, Sung Kuk; Share, Andrew; Lynch, Vincent M.; Park, Jinhong; Namkung, Wan; van Rossom, Wim; Busschaert, Nathalie; Gale, Philip A.; Sessler, Jonathan L.; Shin, Injae

    2014-10-01

    Anion transporters based on small molecules have received attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis. However, a direct correlation between a change in cellular chloride anion concentration and cytotoxicity has not been established for synthetic ion carriers. Here we show that two pyridine diamide-strapped calix[4]pyrroles induce coupled chloride anion and sodium cation transport in both liposomal models and cells, and promote cell death by increasing intracellular chloride and sodium ion concentrations. Removing either ion from the extracellular media or blocking natural sodium channels with amiloride prevents this effect. Cell experiments show that the ion transporters induce the sodium chloride influx, which leads to an increased concentration of reactive oxygen species, release of cytochrome c from the mitochondria and apoptosis via caspase activation. However, they do not activate the caspase-independent apoptotic pathway associated with the apoptosis-inducing factor. Ion transporters, therefore, represent an attractive approach for regulating cellular processes that are normally controlled tightly by homeostasis.

  8. Method for preparation of melts of alkali metal chlorides with highly volatile polyvalent metal chlorides

    International Nuclear Information System (INIS)

    A method for production of alkali metal (Cs, Rb, K) chloride melts with highly volatile polyvalent metal chlorides is suggested. The method consists, in saturation of alkali metal chlorides, preheated to the melting point, by volatile component vapours (titanium tetrachloride, molybdenum or tantalum pentachloride) in proportion, corresponding to the composition reguired. The saturation is realized in an evacuated vessel with two heating areas for 1-1.5 h. After gradual levelling of temperature in both areas the product is rapidly cooled. 1 fig.; 1 tab

  9. Oral cadmium chloride intoxication in mice

    DEFF Research Database (Denmark)

    Andersen, O; Nielsen, J B; Svendsen, P

    1988-01-01

    Diethyldithiocarbamate (DDC) is known to alleviate acute toxicity due to injection of cadmium salts. However, when cadmium chloride was administered by the oral route, DDC enhanced rather than alleviated the acute toxicity; both oral and intraperitoneal (i.p.) administration of DDC had this effec...

  10. Liquid crystalline critical dynamics in decylammonium chloride

    CERN Document Server

    Lee, K W; Lee, C E; Kang, K H; Rhee, C; Kang, J K

    1999-01-01

    Collective chain dynamics and phase transitions in a model biomembrane, decylammonium chloride (C sub 1 sub 0 H sub 2 sub 1 NH sub 3 Cl), were studied by means of proton nuclear magnetic resonance. Our measurements sensitively reflect the critical dynamics associated with the smectic C to smectic A transition of the lipid bilayer.

  11. Liquid crystalline critical dynamics in decylammonium chloride

    International Nuclear Information System (INIS)

    Collective chain dynamics and phase transitions in a model biomembrane, decylammonium chloride (C10H21NH3Cl), were studied by means of proton nuclear magnetic resonance. Our measurements sensitively reflect the critical dynamics associated with the smectic C to smectic A transition of the lipid bilayer

  12. Chloride diffusion in partially saturated cementitious material

    DEFF Research Database (Denmark)

    Nielsen, Erik Pram; Geiker, Mette Rica

    2003-01-01

    The paper proposes a combined application of composite theory and Powers' model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg...

  13. 75 FR 19657 - Barium Chloride From China

    Science.gov (United States)

    2010-04-15

    ... Commission found that the domestic interested party group response to its notice of institution (74 FR 31757... COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Notice of Commission determination to conduct a full five-year review concerning the antidumping duty order on...

  14. 75 FR 20625 - Barium Chloride From China

    Science.gov (United States)

    2010-04-20

    ... established a schedule for the conduct of this review (74 FR 62587, November 30, 2010). Subsequently, counsel... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION:...

  15. Chloride concentration affects soil microbial community

    Czech Academy of Sciences Publication Activity Database

    Gryndler, Milan; Rohlenová, Jana; Kopecký, Jan; Matucha, Miroslav

    2008-01-01

    Roč. 71, č. 7 (2008), s. 1401-1408. ISSN 0045-6535 R&D Projects: GA ČR GA526/05/0636 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50380511 Keywords : soil chloride * terminal restriction fragments * soil microorganisms Subject RIV: EE - Microbiology, Virology Impact factor: 3.054, year: 2008

  16. Determination of chloride in uranium solutions

    Energy Technology Data Exchange (ETDEWEB)

    Danse, A.; Stoch, H.; Steele, T.W.

    1967-05-15

    Thiocyanate is first removed by precipitation with a small excess of a copper solution, and the cations are removed by passing the filtrate through a cation-exchange resin. The chloride is determined in the eluate by a potentiometric titration in which silver nitrate solution is used.

  17. Amperometric Sensor for Detection of Chloride Ions

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2008-09-01

    Full Text Available Chloride ion sensing is important in many fields such as clinical diagnosis, environmental monitoring and industrial applications. We have measured chloride ions at a carbon paste electrode (CPE and at a CPE modified with solid AgNO3, a solution of AgNO3 and/or solid silver particles. Detection limits (3 S/N for chloride ions were 100 μM, 100 μM and 10 μM for solid AgNO3, solution of AgNO3 and/or solid silver particles, respectively. The CPE modified with silver particles is the most sensitive to the presence chloride ions. After that we approached to the miniaturization of the whole electrochemical instrument. Measurements were carried out on miniaturized instrument consisting of a potentiostat with dimensions 35 × 166 × 125 mm, screen printed electrodes, a peristaltic pump and a PC with control software. Under the most suitable experimental conditions (Britton-Robinson buffer, pH 1.8 and working electrode potential 550 mV we estimated the limit of detection (3 S/N as 500 nM.

  18. Polyvinyl chloride filled with bismuth oxychloride powder

    Czech Academy of Sciences Publication Activity Database

    Polášková, M.; Sedláček, T.; Kharlamov, Alexander; Pivokonský, Radek; Saha, P.

    Larnaca : Polymer Processing Society, 2009, s. 242. [Polymer Processing Society Europe/Africa Regional Meeting. Larnaca (GR), 18.10.2009-21.10.2009] Institutional research plan: CEZ:AV0Z20600510 Keywords : olyvinyl chloride * bismuth oxychloride * radiopaque agents Subject RIV: BK - Fluid Dynamics

  19. Binary nucleation of water and sodium chloride

    Czech Academy of Sciences Publication Activity Database

    Němec, Tomáš; Maršík, František; Palmer, A.

    2006-01-01

    Roč. 124, č. 4 (2006), 0445091-0445096. ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA101/05/2536 Institutional research plan: CEZ:AV0Z20760514 Keywords : binary nucleation * sodium chloride * water Subject RIV: BJ - Thermodynamics Impact factor: 3.166, year: 2006

  20. 21 CFR 184.1446 - Manganese chloride.

    Science.gov (United States)

    2010-04-01

    ..., and crystallized. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese chloride. 184.1446 Section 184.1446 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  1. Close-ups

    DEFF Research Database (Denmark)

    Fausing, Bent

    2013-01-01

    Investigations in the close-up and its meaning regarding nearness, abstraction and transparency. Face, facelike and animism are also major key-words in thsi article... . I have always been fascinated with the close-up, not as an end, but a filter of opportunities to open up for and nearness of...... transcendence, associations and memories. The close-up is not the end, it rather in my view to be regarded as a beginning of different perceptions...

  2. Multilevel Polarization of Polar Codes Over Arbitrary Discrete Memoryless Channels

    OpenAIRE

    Sahebi, Aria G.; Pradhan, S. Sandeep

    2011-01-01

    It is shown that polar codes achieve the symmetric capacity of discrete memoryless channels with arbitrary input alphabet sizes. It is shown that in general, channel polarization happens in several, rather than only two levels so that the synthesized channels are either useless, perfect or "partially perfect". Any subset of the channel input alphabet which is closed under addition, induces a coset partition of the alphabet through its shifts. For any such partition of the input alphabet, ther...

  3. The role of concrete resistivity in chloride-induced macro-cell corrosion of reinforcement

    OpenAIRE

    Hornbostel, Karla

    2015-01-01

    Norwegian concrete structures are exposed to salt contamination from both sea water and de-icing salts. Chlorides penetrate the concrete cover and initiate corrosion of the reinforcement. The deterioration process can propagate at high rates and endanger serviceability and structural safety. Concrete resistivity is usually assumed to correlate closely with the corrosion process, and its measurement is in principle simple and costefficient, and widely recommended to support serv...

  4. Hydrolysis of ferric chloride in solution

    Energy Technology Data Exchange (ETDEWEB)

    Lussiez, G.; Beckstead, L.

    1996-11-01

    The Detox{trademark} process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200{degrees}C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl{sub 3 liquid} + H{sub 2}O {r_arrow} FeOCl{sub solid} + 2 HCl{sub gas} During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOCl{sub solid} + H{sub 2}O {r_arrow} Fe{sub 2}O{sub 3 solid} + 2 HCl{sub gas}. The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way.

  5. Viscosity and density tables of sodium chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fair, J.A.; Ozbek, H. (comps.)

    1977-04-01

    A file is presented containing tabulated data extracted from the scientific literature on the density and viscosity of aqueous sodium chloride solutions. Also included is a bibliography of the properties of aqueous sodium chloride solutions. (MHR)

  6. Nitrate and chloride in Antarctic ice cores - postdepositional effects and the preservation of atmospheric signals (Invited)

    Science.gov (United States)

    Pasteris, D.; McConnell, J. R.; Edwards, R.; Isaksson, E. D.; Albert, M. R.

    2013-12-01

    Continuous nitrate and chloride measurements have been made from an array of ice cores located in interior Dronning Maud Land that cover the last 2000 years. The average snow accumulation rates at the ice core sites range from 2.7 to 10 cm weq yr-1, which has enabled the study of how accumulation rate affects the preservation and diffusion of nitrate and chloride in the snow. High-resolution dating of the ice cores by tie-point matching with the WAIS Divide ice core has allowed the effects of temporal changes in accumulation rate to also be observed. Results show a strong linear dependence of nitrate concentration on site-average accumulation rate, suggesting that fresh snow concentrations and reemission rates of nitrate from the snowpack are homogenous across the study area. Bulk chloride to sodium ratios over scales greater than 1 m are close to bulk sea salt composition at all of the sites, suggesting that little net gain or loss of volatile chloride has occurred. However, the chloride signal is heavily diffused relative to sodium and the extent of diffusion does not increase with depth in the ice cores, suggesting that it is a near-surface phenomenon. Possible mechanisms behind the observed chloride diffusion pattern will be discussed. Lastly, a sustained decline in nitrate concentration occurred during the Little Ice Age (LIA, 1500-1900 C.E.), but the high-resolution snow accumulation records show that it is not caused by a decrease in accumulation rate during that time. The nitrate record is highly correlated with published methane isotope data from Antarctica (δ13CH4), suggesting that the decline during the LIA was caused by a decrease in a biomass burning nitrate source. Average nitrate concentration versus site-average inverse accumulation rate Composite time series of nitrate (thick black line), δ13CH4 (thin red line with diamonds), and black carbon (dashed black line).

  7. 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...

  8. Removal of iron contaminant from zirconium chloride solution

    International Nuclear Information System (INIS)

    This patent describes a process for eliminating iron contaminant from an aqueous zirconium chloride solution that has been contaminated with FeCl3 in a plant in which zirconium and hafnium chloride solutions are separated by a main MINK solvent extraction system and the FeCl3 is normally removed from the zirconium chloride solution by a secondary MINK solvent extraction system

  9. Kinetics of Vinyl Chloride Polymerization with Mixture of Initiators

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with uniform rate at different temperatures at which various grades of poly(vinyl chloride) will be prepared.

  10. Secretion by the nasal salt glands of two insectivorous lizard species is initiated by an ecologically relevant dietary ion, chloride.

    Science.gov (United States)

    Hazard, Lisa C; Lechuga, Claudia; Zilinskis, Stephanie

    2010-08-01

    Salt glands are used by some vertebrates to excrete hyperosmotic NaCl or KCl solutions in response to dietary salt loads. Control of secretion varies across taxa; some secrete in response to osmotic challenges while others secrete in response to specific dietary ions. We hypothesized that differences in control could be related to different diet-related selective pressures on herbivorous, marine, and insectivorous species. We studied control of secretion and flexibility of cation (sodium or potassium) and anion (chloride or bicarbonate) secretion in two insectivorous lizard species, Schneider's skinks (Eumeces schneideri, Scincidae) and green anoles (Anolis carolinensis, Polychrotidae). Lizards were injected daily for four days with combinations of cations (potassium, sodium, and histidine control) and anions (chloride and acetate control), isoosmotic saline, or sham injection. Secretions were collected daily and analyzed for sodium, potassium, and chloride. Both species secreted only in response to chloride; sodium appeared to have a slight inhibitory effect. Regardless of cation load, skinks secreted a combination of potassium and sodium, while anoles secreted solely potassium. In both species, total cation secretion was matched closely by chloride; very little bicarbonate was secreted. As predicted, secretion in insectivorous lizards was initiated by the dietary ion ecologically most important for these species, chloride, which otherwise cannot be excreted without significant water loss (unlike the cations, which may be excreted as insoluble urate salts). This gives further support to the hypothesis that ecological factors drive the evolution of control mechanisms in lizard salt glands. PMID:20623801

  11. Effect of diets containing different levels of calcium, phosphate, and vitamin D3 on tooth uptake of 47Ca-chloride in rat models

    International Nuclear Information System (INIS)

    The effect of dietary manipulation on global tooth uptake of 47Ca-chloride was evaluated in three rat models of metabolic bone diseases verified by histologic bone study. The 24-hr tooth uptake of 47Ca-chloride was significantly decreased in the osteomalacic group, and was increased in the osteoporotic group at the fourth week. Tooth uptake closely paralleled femoral uptake at a correlation coefficient of 0.73 (p47Ca-chloride in tooth was found to be more affected by dietary manipulation than that in femur in our rat models. (author)

  12. Revised Model of Chloride Diffusion in Concrete Bridge by Considering Complex Action of Load and Chloride Binding Capacity

    OpenAIRE

    Xiang, Yiqiang; Guo, DongMei

    2014-01-01

    Coastal concrete bridges will suffer from deterioration of RC structural performance and resistance attenuation because of the chloride penetration and other environment factors. This article discusses current different chloride diffusion models and puts forward the revised model of chloride diffusion in concrete bridge by considering the complex action of load influence and chloride-binding capacity. Comparison of numerical predicted values and relative experimental tests show the presented ...

  13. 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...

  14. Increased excitability of acidified skeletal muscle: role of chloride conductance.

    Science.gov (United States)

    Pedersen, Thomas H; de Paoli, Frank; Nielsen, Ole B

    2005-02-01

    Generation of the action potentials (AP) necessary to activate skeletal muscle fibers requires that inward membrane currents exceed outward currents and thereby depolarize the fibers to the voltage threshold for AP generation. Excitability therefore depends on both excitatory Na+ currents and inhibitory K+ and Cl- currents. During intensive exercise, active muscle loses K+ and extracellular K+ ([K+]o) increases. Since high [K+]o leads to depolarization and ensuing inactivation of voltage-gated Na+ channels and loss of excitability in isolated muscles, exercise-induced loss of K+ is likely to reduce muscle excitability and thereby contribute to muscle fatigue in vivo. Intensive exercise, however, also leads to muscle acidification, which recently was shown to recover excitability in isolated K(+)-depressed muscles of the rat. Here we show that in rat soleus muscles at 11 mM K+, the almost complete recovery of compound action potentials and force with muscle acidification (CO2 changed from 5 to 24%) was associated with reduced chloride conductance (1731 +/- 151 to 938 +/- 64 microS/cm2, P < 0.01) but not with changes in potassium conductance (405 +/- 20 to 455 +/- 30 microS/cm2, P < 0.16). Furthermore, acidification reduced the rheobase current by 26% at 4 mM K+ and increased the number of excitable fibers at elevated [K+]o. At 11 mM K+ and normal pH, a recovery of excitability and force similar to the observations with muscle acidification could be induced by reducing extracellular Cl- or by blocking the major muscle Cl- channel, ClC-1, with 30 microM 9-AC. It is concluded that recovery of excitability in K(+)-depressed muscles induced by muscle acidification is related to reduction in the inhibitory Cl- currents, possibly through inhibition of ClC-1 channels, and acidosis thereby reduces the Na+ current needed to generate and propagate an AP. Thus short term regulation of Cl- channels is important for maintenance of excitability in working muscle. PMID:15684096

  15. Polyunsaturated fatty acids modify the gating of Kv channels

    Directory of Open Access Journals (Sweden)

    Cristina eMoreno

    2012-09-01

    Full Text Available Polyunsaturated fatty acids (PUFAs have been reported to exhibit antiarrhythmic properties, which are attributed to their capability to modulate ion channels. This PUFAs ability has been reported to be due to their effects on the gating properties of ion channels. In the present review, we will focus on the role of PUFAs on the gating of two Kv channels, Kv1.5 and Kv11.1. Kv1.5 channels are blocked by n-3 PUFAs of marine (docosahexaenoic and eicosapentaenoic acid, DHA and EPA and plant origin (alpha-linolenic acid, ALA at physiological concentrations. The blockade of Kv1.5 channels by PUFAs steeply increased in the range of membrane potentials coinciding with those of Kv1.5 channel activation, suggesting that PUFAs-channel binding may derive a significant fraction of its voltage sensitivity through the coupling to channel gating. A similar shift in the activation voltage was noted for the effects of arachidonic acid (AA and DHA on Kv1.1, Kv1.2, and Kv11.1 channels. PUFAs-Kv1.5 channel interaction is time-dependent, producing a fast decay of the current upon depolarization. Thus, Kv1.5 channel opening is a prerequisite for the PUFA-channel interaction. Similar to the Kv1.5 channels, the blockade of Kv11.1 channels by AA and DHA steeply increased in the range of membrane potentials that coincided with the range of Kv11.1 channel activation, suggesting that the PUFAs-Kv channel interactions are also coupled to channel gating. Furthermore, AA regulates the inactivation process in other Kv channels, introducing a fast voltage-dependent inactivation in non-inactivating Kv channels. These results have been explained within the framework that AA closes voltage-dependent potassium channels by inducing conformational changes in the selectivity filter, suggesting that Kv channel gating is lipid dependent.

  16. STABILISATION OF SILTY CLAY SOIL USING CHLORIDE

    Directory of Open Access Journals (Sweden)

    TAMADHER T. ABOOD

    2007-04-01

    Full Text Available The object of this paper is to investigate the effect of adding different chloride compounds including (NaCl, MgCl2, CaCl2 on the engineering properties of silty clay soil. Various amounts of salts (2%, 4%, and 8% were added to the soil to study the effect of salts on the compaction characteristics, consistency limits and compressive strength. The main findings of this study were that the increase in the percentage of each of the chloride compounds increased the maximum dry density and decrease the optimum moisture content. The liquid limit, plastic limit and plasticity index decreased with the increase in salt content. The unconfinedcompressive strength increased as the salt content increased.

  17. BARRIER PROPERTIES OF VINYLIDENE CHLORIDE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    LI Yuesheng; WENG Zhixue; HUANG Zhiming; PAN Zuren

    1996-01-01

    The permeability coefficients of a series of copolymers of vinylidene chloride (VDC)with methyl acrylate (MA), butyl acrylate (BA) or vinyl chloride (VC) (as comonomer)to oxygen and carbon dioxide have been measured at 1.0 MPa and 30℃, while those to water vapor have been measured at 30℃ and 100% relative humidity. All the copolymers are semicrystalline. VDC/MA copolymers have lower melting temperature compared with VDC/BA copolymers, while that melting temperature of VDC/VC copolymer is higher than that of VDC/acrylate copolymers with the same VDC content. The barrier property of the copolymers is predominantly controlled by crystallite, free volume fraction, and cohesive energy. The permeability coefficients of VDC/MA copolymers to oxygen, carbon dioxide, and water vapor were successfully correlated with the ratio of free volume to cohesive energy.

  18. Chloride migration in concrete with superabsorbent polymers

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2015-01-01

    Superabsorbent polymers (SAP) can be used as a means for internal curing of concrete. In the present study, the development of transport properties of concrete with SAP is investigated. The chloride migration coefficient according to NT BUILD 492 is used as a measure of this. Twenty concrete...... mixtures are tested 7, 14, and 28 days after casting. The development of degree of hydration is followed for 20 corresponding paste mixtures. Both when SAP is added with extra water to compensate the SAP water absorption in fresh concrete and without extra water, the internal curing water held by SAP may...... contribute to increase the degree of hydration. No matter if SAP is added with or without extra water, it appears that the so-called gel space ratio can be used as a key parameter to link age and mixture proportions (water-to-cement ratio and SAP dosage) to the resulting chloride migration coefficient; the...

  19. Influence of chloride admixtures on cement matrix durability

    International Nuclear Information System (INIS)

    The influence of various inorganic salts, as chloride admixtures to Portland cement, on the mechanical properties and the durability of the matrix has been studied. The salts used in this study are chromium, nickel and cadmium chlorides. Improved compressive strength values are obtained which have been correlated to the stable metal hydroxide formation in high pH environment. Under static water conditions at 500C, hydrolyzed chloride ions exhibit adverse effects on the matrix durability through rapid release of calcium as calcium chloride in the initial period of leaching. On the contrary, enhanced matrix durability is obtained on long term leaching in the case of cement containing chromium chloride

  20. Acylation of Toluene with Isobutyryl Chloride

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří; Klisáková, Jana; Žilková, Naděžda; Červený, L.

    Cape Town, 2004 - ( Steen van, E.), s. 2717-2723 ISBN 0-958-46636-X. [International Zeolite Conference /14./. Cape Town (ZA), 25.04.2004-30.04.2004] R&D Projects: GA ČR GA203/03/0804 Institutional research plan: CEZ:AV0Z4040901 Keywords : acylation of toluene * isobutyryl chloride * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Chloride migration in concrete with superabsorbent polymers

    OpenAIRE

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2015-01-01

    Superabsorbent polymers (SAP) can be used as a means for internal curing of concrete. In the present study, the development of transport properties of concrete with SAP is investigated. The chloride migration coefficient according to NT BUILD 492 is used as a measure of this. Twenty concrete mixtures aretested 7, 14, and 28 days after casting. The development of degree of hydration is followed for 20 corresponding paste mixtures.Both when SAP is added with extra water to compensate the SAP wa...

  2. Gasometric titration for dimethylaluminum chloride analysis.

    Science.gov (United States)

    Wang, Lin; Maligres, Peter; Eckenroad, Kyle; Simmons, Bryon

    2016-06-01

    A gasometric titration method was developed to quantitate active alkylaluminum content in dimethylaluminum chloride solution to perform the stoichiometry calculation for the reaction charge. The procedure was reproducible with good precision, and the results showed good correlation with ICP-MS method. The gasometric titration is a simple, inexpensive alternative to analysis via ICP-MS which provides more selective analysis of methylaluminum species without the need for inertion. PMID:27017569

  3. A Duplex Stainless Steel for Chloride Environments

    Science.gov (United States)

    Sridhar, N.; Kolts, J.; Flasche, L. H.

    1985-03-01

    This paper examines the effects of microstructural changes on the corrosion, stress corrosion cracking and corrosion fatigue resistance of a duplex stainless steel to chloride environments. The microstructural changes can be precipitation of phases such as sigma and carbides, or changes in the distribution of austenite and ferrite. The former can be important in hot forming operations while the latter is important in welding. The methods of minimizing these deleterious effects can sometimes be different from those used for austenitic stainless steel.

  4. Electrodeposition of Zinc from Chloride Solution

    OpenAIRE

    NAIK, Yanjerappa Arthoba; VENKATESHA, Thimmappa Venkatarangaiah

    2002-01-01

    The electroplating of zinc is carried out in the presence of 3,4,5-Trimethoxy benzaldehyde from a chloride bath. The bath constituents are optimized through Hull cell experiments. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency and throwing power are measured at different current densities. Polarization study is carried out under galvanostatic conditions. Corrosion resistance test indicated good protection of steel by the ...

  5. Electrochemical behaviours of scandium in chloride melts

    International Nuclear Information System (INIS)

    Electrochemical behaviour of scandium(3) ions in an eutectic melt of NaCl-KCl-CsCl at 810-850 K is studied by cyclic voltammetry and chronoamperometry. The process of cathodic reduction of scandium complex ions in chloride melts is found to proceed according to the scheme: Sc(3) → Sc(0) and to be controlled by the rate of ScCl63- complex dissociation

  6. (tert-Butyl(2-hydroxyethylammonium chloride

    Directory of Open Access Journals (Sweden)

    Cintya Valerio-Cárdenas

    2014-07-01

    Full Text Available In the cation of the title molecular salt, C6H16NO+·Cl−, the N—C—C—O torsion angle is 176.5 (2°. In the crystal, the cations and chloride ions are linked by N—H...O and O—H...O hydrogen bonds, generating a two-dimensional network parallel to (100.

  7. Manganese laser using manganese chloride as lasant

    Science.gov (United States)

    Chen, C. J.

    1974-01-01

    A manganese vapor laser utilizing manganese chloride as a lasant has been observed and investigated. Lasing is attained by means of two consecutive electrical discharges. The maximum laser output is obtained at a vapor pressure of about 3 torr, a temperature of 680 C, and a time delay between electrical discharges of 150 microsec. The maximum energy density is 1.3 microjoule per cu cm.

  8. Closed Claim Query File

    Data.gov (United States)

    Social Security Administration — This file is used to hold information about disability claims that have been closed and have been selected for sampling.Sampling is the process whereby OQR reviews...

  9. Mitigation : Closed Basin Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The upcoming meeting on waterfowl mitigation for the Closed Basin Project will have several people talk about possible changes to the waterfowl mitigation program....

  10. An autopsy case of zinc chloride poisoning.

    Science.gov (United States)

    Kondo, Takeshi; Takahashi, Motonori; Watanabe, Seiya; Ebina, Masatomo; Mizu, Daisuke; Ariyoshi, Koichi; Asano, Migiwa; Nagasaki, Yasushi; Ueno, Yasuhiro

    2016-07-01

    Ingestion of large amounts of zinc chloride causes corrosive gastroenteritis with vomiting, abdominal pain, and diarrhea. Some individuals experience shock after ingesting large amounts of zinc chloride, resulting in fatality. Here, we present the results of an administrative autopsy performed on a 70-year-old man who ingested zinc chloride solution and died. After drinking the solution, he developed vomiting, abdominal pain, and diarrhea, and called for an ambulance. Except for tachycardia, his vital signs were stable at presentation. However, he developed hypotension and severe metabolic acidosis and died. The patient's blood zinc concentration on arrival was high at 3030μg/dL. Liver cirrhosis with cloudy yellow ascites was observed, however, there were no clear findings of gastrointestinal perforation. The gastric mucosa was gray-brown, with sclerosis present in all gastric wall layers. Zinc staining was strongly positive in all layers. There was almost no postmortem degeneration of the gastric mucosal epithelium, and hypercontracture of the smooth muscle layer was observed. Measurement of the zinc concentration in the organs revealed the highest concentration in the gastric mucosa, followed by the pancreas and spleen. Clinically, corrosive gastroenteritis was the cause of death. However, although autopsy revealed solidification in the esophagus and gastric mucosa, there were no findings in the small or large intestine. Therefore, metabolic acidosis resulting from organ damage was the direct cause of death. PMID:27497327

  11. Potassium chloride production by microcline chlorination

    International Nuclear Information System (INIS)

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl2–N2 mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated

  12. Microwave spectrum and structure of nitrosyl chloride

    International Nuclear Information System (INIS)

    The microwave spectra of 15N isotopic species of nitrosyl chloride, 15NO35Cl and 15NO37Cl, have been assigned between 8 and 26 GHz, and the following rotational constants have been obtained: A = 81600 MHz, B = 5693.80 MHz, and C = 5322.44 MHz for 15NO35Cl, A = 81520 MHz, B = 5556.07 MHz, and C = 5201.56 MHz for 15NO37Cl. The microwave spectra of the normal species of nitrosyl chloride as well as the 37Cl species and the 18O species have already been measured by Millen et al. (1961). An analysis of both the rotational constants obtained in this study and the constants by Millen et al. has given the following bond lengths and angle as the complete r sub(s) structural parameters of nitrosyl chloride. r(N-O) = 1.143 +- 0.006 A, r(N-Cl) = 1.973 +- 0.003 A, and 0 +- 0.50. The nuclear quadrupole coupling constants in the N-Cl bond axis system of 15NO35Cl are X sub(zz) = -57.8 MHz and eta = -0.311. (author)

  13. Boldine action against the stannous chloride effect.

    Science.gov (United States)

    Reiniger, I W; Ribeiro da Silva, C; Felzenszwalb, I; de Mattos, J C; de Oliveira, J F; da Silva Dantas, F J; Bezerra, R J; Caldeira-de-Araújo, A; Bernardo-Filho, M

    1999-12-15

    Peumus boldus extract has been used in popular medicine in the treatment of biliar litiase, hepatic insufficiency and liver congestion. Its effects are associated to the substance boldine that is present in its extract. In the present work, we evaluated the influence of boldine both in: (i) the structural conformation of a plasmid pUC 9.1 through gel electrophoresis analysis; and in (ii) the survival of the strain of Escherichia coli AB1157 submitted to reactive oxygen species (ROS), generated by a Fenton like reaction, induced by stannous chloride. Our results show a reduction of the lethal effect induced by stannous chloride on the survival of the E. coli culture in the presence of boldine. The supercoiled form of the plasmid is not modified by stannous chloride in the presence of boldine. We suggest that the protection induced by boldine could be explained by its anti-oxidant mechanism. In this way, the boldine could be reacting with stannous ions, protecting them against the oxidation and, consequently, avoiding the generation of ROS. PMID:10624900

  14. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  15. Solubility of sodium chloride in superheated steam

    International Nuclear Information System (INIS)

    The solubility of sodium chloride in superheated steam was investigated in laboratory-scale experiments up to 20 MPa and 475 C. These experiments were carried out using a dynamic method where deionized steam was passed through a packed bed of salt crystals in a 500 mL Hastelloy autoclave. The residence time of the steam in the salt bed was sufficient to saturate the steam with the salt. The steam samples were cooled and analyzed by ion chromatography. Correlations based on temperature and density were selected to describe the solubility of sodium chloride in superheated steam. The density dependence is much stronger than the temperature dependence. By using these correlations, it is possible to estimate the solubility of salt in steam at lower densities than those used in the experiments. Enthalpy-entropy diagrams are given that show the steam expansion line in turbines, including curves for constant concentration of sodium chloride solubility in steam. These can be used to analyze where in the steam cycle this salt may deposit. (orig.)

  16. ICEPO: the ion channel electrophysiology ontology.

    Science.gov (United States)

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  17. The Accelerated Test of Chloride Permeability of Concrete

    Institute of Scientific and Technical Information of China (English)

    TAN Ke-feng; ODD E Gjφrv

    2003-01-01

    The availability of accelerated chloride permeability test and the effect of w/c ratio, incorporation of silica fume, maximum aggregate size and aggregate type on the chloride permeability were studied. The mathematic analysis certifies that there is a linear relationship between accelerated test and natural diffusion. Test results show that the chloride permeability of concrete increases as w/c ratio increases whilst a limited amount of replacement of cement with silica fume, the chloride permeability decreases dramatically. The maximum aggregate size in the range of 8 to 25 mm seems also affect chloride permeability but with a much less significant level. The chloride permeability of silica fume lightweight aggregate concrete is very low, especially the concrete made with dry lightweight concrete. The chloride permeability can be evaluated by this accelerated test method.

  18. 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

  19. A truncated CFTR protein rescues endogenous ΔF508-CFTR and corrects chloride transport in mice

    OpenAIRE

    Cormet-Boyaka, Estelle; Jeong S Hong; Berdiev, Bakhram K.; James A Fortenberry; Rennolds, Jessica; Clancy, J. P.; Benos, Dale J.; Boyaka, Prosper N.; Sorscher, Eric J.

    2009-01-01

    Cystic fibrosis (CF) is most frequently associated with deletion of phenylalanine at position 508 (ΔF508) in the CF transmembrane conductance regulator (CFTR) protein. The ΔF508-CFTR mutant protein exhibits a folding defect that affects its processing and impairs chloride-channel function. This study aimed to determine whether CFTR fragments approximately half the size of wild-type CFTR and complementary to the portion of CFTR bearing the mutation can specifically rescue the processing of end...

  20. Chloride permeability of rat brain membrane vesicles correlates with thiamine triphosphate content.

    Science.gov (United States)

    Bettendorff, L; Hennuy, B; De Clerck, A; Wins, P

    1994-07-25

    Incubation of rat brain homogenates with thiamine or thiamine diphosphate (TDP) leads to a synthesis of thiamine triphosphate (TTP). In membrane vesicles subsequently prepared from the homogenates, increased TTP content correlates with increased 36Cl- uptake. A hyperbolic relationship was obtained with a K0.5 of 0.27 nmol TTP/mg protein. In crude mitochondrial fractions from the brains of animals previously treated with thiamine or sulbutiamine, a positive correlation between 36Cl- uptake and TTP content was found. These results, together with other results previously obtained with the patch-clamp technique, suggest that TTP is an activator of chloride channels having a large unit conductance. PMID:7953714

  1. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, M., E-mail: m.suarez@cinn.e [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Fernandez, A. [Fundacion ITMA, Parque Tecnologico de Asturias, 33428, Llanera (Spain); Menendez, J.L.; Torrecillas, R. [Departamento de Materiales Nanoestructurados, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN), Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)

    2010-03-18

    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 {sup o}C by the chlorides route, whereas alkoxide precursors needed firing over 900 {sup o}C and nitrates even over 1100 {sup o}C. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 {sup o}C with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  2. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    International Nuclear Information System (INIS)

    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 oC by the chlorides route, whereas alkoxide precursors needed firing over 900 oC and nitrates even over 1100 oC. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 oC with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  3. Relation between chloride exchange diffusion and a conductive chloride pathway across the isolated skin of the toad (Bufo bufo)

    DEFF Research Database (Denmark)

    Kristensen, P; Larsen, Erik Hviid

    1978-01-01

    Substitution of chloride in the outside bathing medium of the toad skin with bromide, iodide, nitrate and sulphate leads to a reduction in the apparent exchange diffusion of chloride across this tissue, and also to a reduction of the chloride current recorded during hyperpolarization. A series of...... systems could be explained as secondary effects due to a primary interaction with the sodium transport mechanisms. A correlation was found between the clamping current recorded during hyperpolarization and the efflux of chloride under short circuit conditions with chloride Ringer's on both sides. On the...

  4. 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

  5. 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.

  6. 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.

  7. Closed Spaces in Cosmology

    CERN Document Server

    Fagundes, Helio V

    2008-01-01

    This paper deals with two aspects of relativistic cosmologies with closed (compact and boundless) spatial sections. These spacetimes are based on the theory of General Relativity, and admit a foliation into space sections, which are spacelike hypersurfaces satisfying the postulate of the closure of space: each is a 3-dimensional closed Riemannian manifold. The discussed topics are: (1) A comparison, previously obtained, between Thurston's geometries and Bianchi-Kantowski-Sachs metrics for such 3-manifolds is here clarified and developed. (2) Some implications of global inhomogeneity for locally homogeneous 3-spaces of constant curvature are analyzed from an observational viewpoint.

  8. 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.

  9. Retail Services and Pricing Decisions in a Closed-Loop Supply Chain with Remanufacturing

    OpenAIRE

    Zhen-Zheng Zhang; Zong-Jun Wang; Li-Wen Liu

    2015-01-01

    Environmental and social responsibilities have led many manufacturers to used products recovery. Meanwhile, many manufacturers nowadays sell products via indirect retailer channels and direct Internet channels. This paper models a dual-channel closed-loop supply chain to improve the sustainability of products. We apply the two-stage optimization technique and the Nash game to examine the impacts of the retail services and the degree of customer loyalty to the retail channel on the pricing of ...

  10. VGIchan: Prediction and Classification of Voltage-Gated Ion Channels

    Institute of Scientific and Technical Information of China (English)

    Sudipto Saha; Jyoti Zack; Balvinder Singh; G.P.S. Raghava

    2006-01-01

    This study describes methods for predicting and classifying voltage-gated ion channels. Firstly, a standard support vector machine (SVM) method was developed for predicting ion channels by using amino acid composition and dipeptide composition, with an accuracy of 82.89% and 85.56%, respectively. The accuracy of this SVM method was improved from 85.56% to 89.11% when combined with PSIBLAST similarity search. Then we developed an SVM method for classifying ion channels (potassium, sodium, calcium, and chloride) by using dipeptide composition and achieved an overall accuracy of 96.89%. We further achieved a classification accuracy of 97.78% by using a hybrid method that combines dipeptidebased SVM and hidden Markov model methods. A web server VGIchan has been developed for predicting and classifying voltage-gated ion channels using the above approaches. VGIchan is freely available at www.imtech.res.in/raghava/vgichan/.

  11. 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.

  12. Axially shaped channel and integral flow trippers

    International Nuclear Information System (INIS)

    A fuel assembly is described comprising fuel rods positioned in spaced array by upper and lower tie-plates, an open ended flow channel surrounding the array for conducting coolant upward between a lower support plate having coolant communicated thereto to an upper support grid having a steam/water outlet communicated thereto. The flow channel surrounds the array for conducting coolant about the fuel rods. The open ended channel has a polygon shaped cross section with the channel constituting a closed conduit with flat side sections connected at corners to form the enclosed conduit; means separate from the channel for connecting the upper and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel. The improvement in the flow channel comprises tapered side walls. The tapered side walls extend from an average thick cross section adjacent the lower support plate to an average thin cross section adjacent the upper core grid whereby the channel is reduced in thickness adjacent the upper core grid to correspond with the reduced pressure adjacent the upper core grid

  13. Axially shaped channel and integral flow trippers

    Energy Technology Data Exchange (ETDEWEB)

    Crowther, R.L.; Johansson, E.B.; Matzner, B.

    1988-06-07

    A fuel assembly is described comprising fuel rods positioned in spaced array by upper and lower tie-plates, an open ended flow channel surrounding the array for conducting coolant upward between a lower support plate having coolant communicated thereto to an upper support grid having a steam/water outlet communicated thereto. The flow channel surrounds the array for conducting coolant about the fuel rods. The open ended channel has a polygon shaped cross section with the channel constituting a closed conduit with flat side sections connected at corners to form the enclosed conduit; means separate from the channel for connecting the upper and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel. The improvement in the flow channel comprises tapered side walls. The tapered side walls extend from an average thick cross section adjacent the lower support plate to an average thin cross section adjacent the upper core grid whereby the channel is reduced in thickness adjacent the upper core grid to correspond with the reduced pressure adjacent the upper core grid.

  14. Axially shaped channel and integral flow trippers

    Energy Technology Data Exchange (ETDEWEB)

    Crowther, R.L. Jr.; Johansson, E.B.; Matzner, B.

    1992-02-11

    This patent describes a fuel assembly. It comprises: fuel rods positioned in spaced array by upper and lower tie-plates, and open ended flow channel surrounding the array for conducting coolant upward between a lower support plate having coolant communicated thereto to an upper support grid having a steam/water outlet communicated thereto. The flow channel surrounding the array for conducting coolant about the fuel rods; the open ended channel having a polygon shaped cross section with the channel constituting a closed conduit with flat side sections connected at corners to form the enclosed conduit; means separate from the channel for connecting the upper and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel, the improvement in the flow channel comprising tapered side walls, the tapered side walls extending from an average thick cross section adjacent the lower support plate to an average thin cross section adjacent the upper core grid whereby the channel is reduced in thickness adjacent the upper core grid to correspond with the reduced pressure adjacent the upper core grid.

  15. Pd Close Coupled Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhong Hua SHI; Mao Chu GONG; Yao Qiang CHEN

    2006-01-01

    A catalyst comprised novel high surface area alumina support was prepared to control emission of automobiles. The results showed that prepared catalyst could satisfy the requirements of a high performance close coupled catalyst for its good catalytic activity at low temperature and good stability at high temperature.

  16. Molecular mechanisms of carcinogenesis by vinyl chloride.

    Science.gov (United States)

    Dogliotti, Eugenia

    2006-01-01

    In 1974 vinyl chloride (VC), a gas used in the plastics industry, was shown to be a human carcinogen, inducing a very rare type of tumor, angiosarcoma of the liver. The same type of tumor was induced in rodents exposed to VC thus providing an excellent model for mechanistic studies. Here, we review the numerous studies on the mechanism of action of VC with particular emphasis on the DNA products induced by this strong alkylating agent. In particular, the genotoxicity, repair mechanisms, in vivo formation and tumor mutation spectra by etheno-adducts will be analysed and possible approaches for future research suggested. PMID:17033136

  17. Solidification of supercooled molten zinc chloride

    Czech Academy of Sciences Publication Activity Database

    Rodová, Miroslava; Cihlář, Antonín; Nitsch, Karel

    Bratislava: x, 2005 - (Koman, M.; Mikloš, D.), s. 5-9 ISBN 80-89088-42-2. [Development of Materials Science in Research and Education - DMS -RE 2005 /15./. Kežmarské Žĺaby (SK), 05.09.2005-09.09.2005] R&D Projects: GA ČR(CZ) GA202/03/0428 Institutional research plan: CEZ:AV0Z10100521 Keywords : molten zinc chloride * thermal analysis * crystallization * glass formation Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

    Directory of Open Access Journals (Sweden)

    Ekrem Güler

    2011-06-01

    Full Text Available Benzalkonium chloride (BAC is a frequently used disinfectant and its most well-known side effect is contact dermatitis. In this report, two children who had vesicular dermatitis, headache, lethargy, fever and encephalopathy mimicking Herpes zoster encephalitis were presented. Their consciousness level improved on the second day. From the medical history it was understood that the mother had applied 20% BAC solution to the scalps of two children. The aim of the presentation of this report is to draw attention to the fact that BAC application to the scalp for treating pediculosis capitis may resemble the herpes encephalitis clinical picture.

  19. On closed weak supplemented modules

    Institute of Scientific and Technical Information of China (English)

    ZENG Qing-yi; SHI Mei-hua

    2006-01-01

    A module M is called closed weak supplemented if for any closed submodule N of M, there is a submodule K of M such that M=K+N and K(c)N<<M. Any direct summand of closed weak supplemented module is also closed weak supplemented.Any nonsingular image of closed weak supplemented module is closed weak supplemented. Nonsingular V-rings in which all nonsingular modules are closed weak supplemented are characterized in Section 4.

  20. Ergodic Capacity for the SIMO Nakagami-m Channel

    Directory of Open Access Journals (Sweden)

    Efstathios D. Vagenas

    2009-01-01

    Full Text Available This paper presents closed-form expressions for the ergodic channel capacity of SIMO (single-input and multiple output wireless systems operating in a Nakagami-m fading channel. As the performance of SIMO channel is closely related to the diversity combining techniques, we present closed-form expressions for the capacity of maximal ratio combining (MRC, equal gain combining (EGC, selection combining (SC, and switch and stay (SSC diversity systems operating in Nakagami-m fading channels. Also, the ergodic capacity of a SIMO system in a Nakagami-m fading channel without any diversity technique is derived. The latter scenario is further investigated for a large amount of receive antennas. Finally, numerical results are presented for illustration.

  1. Chloride Ingress in Concrete Cracks under Cyclic Loading

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Olesen, John Forbes;

    2005-01-01

    increasing focus on the need for modeling the ingress of chloride into cracked concrete. Present models quantify chloride ingress in static cracks only, although several structural applications display dynamic loading conditions in an environment containing chlorides, e.g. marine structures and car parks....... Preliminary investigations have been undertaken to quantify the effect of dynamic load application on the chloride ingress into concrete cracks. Specimens were designed allowing ingress of a chloride solution into a single crack of a saturated unreinforced mortar beam. One set of specimens was subjected to a...... load frequency of ten applications per minute and a second set to one application per hour simulating static cracks, however limiting the ingress hampering effects of autogenous healing and a possible dense precipitation on the crack faces. The averaged chloride exposure interval of the crack faces was...

  2. Critical assessment of OmpF channel selectivity: merging information from different experimental protocols

    International Nuclear Information System (INIS)

    The ion selectivity of a channel can be quantified in several ways by using different experimental protocols. A wide, mesoscopic channel, the OmpF porin of the outer membrane of E. coli, serves as a case study for comparing and analysing several measures of the channel cation-anion permeability in chlorides of alkali metals (LiCl, NaCl, KCl, CsCl). We show how different insights can be gained and integrated to rationalize the global image of channel selectivity. To this end, reversal potential, channel conductance and bi-ionic potential (two different salts with a common anion on each side of the channel but with the same concentration) experiments are discussed in light of an electrodiffusion model based on the Poisson-Nernst-Planck formalism. Measurements and calculations based on the atomic crystal structure of the channel show that each protocol displays a particular balance between the different sources of selectivity.

  3. Anodic Behavior of Alloy 22 in Calcium Chloride and in Calcium Chloride Plus Calcium Nitrate Brines

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K J; Day, S D; Ilevbare, G O; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-05-13

    Alloy 22 (UNS N60622) is a nickel-based alloy, which is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in concentrated calcium chloride (CaCl{sub 2}) brines and to evaluate the inhibitive effect of nitrate, especially to localized corrosion. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion potential of Alloy 22 was approximately -360 mV in the silver-silver chloride (SSC) scale and independent of the tested temperature. Cyclic polarization tests showed that Alloy 22 was mainly susceptible to localized attack in 5 M CaCl{sub 2} at 75 C and higher temperatures. The addition of nitrate in a molar ratio of chloride to nitrate equal to 10 increased the onset of localized corrosion to approximately 105 C. The addition of nitrate to the solution also decreased the uniform corrosion rate and the passive current of the alloy.

  4. An increase in [Ca2+]i activates basolateral chloride channels and inhibits apical sodium channels in frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Rytved, K A; Nielsen, R

    1996-01-01

    The aim of this study was to investigate the mechanisms by which increases in free cytosolic calcium ([Ca2+]i) cause a decrease in macroscopic sodium absorption across principal cells of the frog skin epithelium. [Ca2+]i was measured with fura-2 in an epifluorescence microscope set-up, sodium...

  5. Joint Synchronization and Channel Estimation for OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    CAO Xue-hong

    2005-01-01

    OFDM systems are extremely sensitive to synchronization and channel estimation imperfections. Meanwhile the timing, frequency synchronization and channel estimation may affect each other. This paper investigates a new algorithm of joint estimation utilizing one training signal which can be used in preamble-based OFDM system, such as IEEE 802.11a WLAN system. The scheme includes two stages for performance improvement and simplicity. At the first stage, the coarse timing and frequency offset and channel response are obtained. The fine synchronization and channel estimation based on the coarse stage are obtained at the second stage. The simulation results show that the channel estimation of the proposed joint estimation is quite close to the case with known sync parameters and the BER of the system is quite close to the case with known channel response.

  6. Interactions between chloride ingress and carbonation in cementitious materials

    OpenAIRE

    SAILLIO, Mickael; BARBERON, Fabien; BAROGHEL BOUNY, Véronique; GEGOUT, Philippe; PLATRET, Gérard; D'ESPINOSE DE LA CAILLERIE, JB

    2011-01-01

    Carbonation and chloride attacks are the major causes of reinforced concrete (RC) structure deterioration by initiation of steel rebar corrosion. These attacks are usually studied separately in the literature. Chloride-induced corrosion takes place mainly in marine environment or in the case of contact with deicing salts, while carbonation is systematically present in all RC structures at a variable degree. Since carbonation leads to significant microstructure changes, the effect of chloride ...

  7. Surface Chloride Concentration of Concrete under Shallow Immersion Conditions

    OpenAIRE

    Jun Liu; Kaifeng Tang; Dong Pan; Zongru Lei; Weilun Wang; Feng Xing

    2014-01-01

    Deposition of chloride ions in the surface layer of concrete is investigated in this study. In real concrete structure, chloride ions from the service environment can penetrate into concrete and deposit in the surface layer, to form the boundary condition for further diffusion towards the interior. The deposit amount of chloride ions in the surface layer is normally a function of time, rather than a constant. In the experimental investigation, concrete specimens with different mix proportions...

  8. Estimating Natural Recharge by Means of Chloride Mass Balance in a Volcanic Aquifer: Northeastern Gran Canaria (Canary Islands, Spain

    Directory of Open Access Journals (Sweden)

    Gema Naranjo

    2015-05-01

    Full Text Available The chloride mass balance method was used to estimate the average diffuse groundwater recharge on northeastern Gran Canaria (Canary Islands, where the largest recharge to the volcanic island aquifer occurs. Rainwater was sampled monthly in ten rainwater collectors to determine the bulk deposition rate of chloride for the 2008–2014 period. Average chloride deposition decreases inwardly from more than 10 g·m−2·year−1 to about 4 g·m−2·year−1. The application of the chloride mass balance method resulted in an estimated average recharge of about 28 hm3/year or 92 mm/year (24% of precipitation in the study area after subtracting chloride loss with surface runoff. The average storm runoff was estimated to be 12 hm3/year (9% of precipitation for the 1980–2014 period. Runoff was sampled during scarce rainy periods, which produce surface water flow. Average recharge varies from less than a few mm/year near the coast up to 270 mm/year in the highlands (about 33% of average rainfall, with a close-to-linear increase inwardly of about 18 mm·year−1·km−1. Recharge rate uncertainty corresponds to an estimated CV of 0.3–0.4 because of the short data series available.

  9. 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 ...

  10. N,N-Dimethyldehydroabietylammonium chloride ethanol monosolvate

    Directory of Open Access Journals (Sweden)

    Xiu-Zhi Huang

    2013-06-01

    Full Text Available The title compound {systematic name: 1-[(1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthren-1-yl]-N,N-dimethylmethanaminium chloride ethanol monosolvate}, C22H36N+·Cl−·C2H6O, was synthesized from dehydroabietylamine by N-methylation with formaldehyde/formic acid and transformation into the hydrochloride. The dehydroabietyl moiety exhibits the usual conformation with the two cyclohexane rings in chair and half-chair conformations and a trans-ring junction. The crystal structure is built up from columns of the dehydroabietyl moieties stacked along the a axis. These columns are held together by the chloride ions via N—H...Cl and C—H...Cl interactions, which establish a two-dimensional network parallel to (010. The ethanol solvent molecules are located between the columns and anchored via O—H...Cl hydrogen bonds.

  11. Radiolytic preparation of anhydrous tin (2) chloride

    Science.gov (United States)

    Philipp, W. H.; Marsik, S. J.

    1973-01-01

    Anhydrous tin (2) chloride (SnCl2) is prepared by radiolysis with high energy electrons of a tin (4) chloride (SnCl4) solution in heptane. The SnCl4 is reduced to insoluble SNCl2. The energy yield, G(SnCl2), molecules of SnCl2, produced per 100 eV, increases with SnCl4 concentration from 1.6 at 0.15 M SnCl4 to 3.1 at 3.0 M SnCl4. Other parameters such as temperature total dose and beam current have little influence on G(SnCl2). The method may be used to prepare other metal halides if the higher valence, more covalent metal halide is soluble in aliphatic hydrocarbons and the lower more ionic metal halide is insoluble. The reaction mechanism is discussed; the radiolysis of both heptane and SnCl4 is involved. At high SnCl4 concentration G(SnCl2) appears to be limited by the yield of SnC13 radicals.

  12. Synthesis and structure characterization of diethyldiallylammonium chloride

    Institute of Scientific and Technical Information of China (English)

    刘立华; 龚竹青; 郑雅杰

    2003-01-01

    The unsaturated quaternary ammonium salt diethyldiallylammonium chloride(DEDAAC) was synthesized in a two-step synthetic method. The influences of the adding method of raw materials and temperature on the yields of diethylallylamine (DEAA), and drying and temperature on the synthesis of DEDAAC were investigated. The content of in-process product DEAA was determined by non-aqueous titration. The structure of product DEDAAC was identified with IR, 1 H NMR and elemental analysis. The results show that adding allyl chloride and sodium hydroxide alternately can increase the yield of DEAA and decrease by-products. In further synthesizing of DEDAAC from DEAA, the step of drying DEAA is very necessary. When DEAA is dried by solid sodium hydroxide, good columnar crystals with a high purity(mp 199.5-201.0 ℃) are obtained; when DEAA is undried or the content of water in DEAA is above 20%, only platelets with bad quality are obtained even without crystals. The suitable synthesis conditions for DEAA and DEDAAC are 35 ℃, 6 h and 40 ℃, 36 h, respectively, and their yields are 69.7% and 67.3%, respectively.

  13. Cobalt electrodeposition using urea and choline chloride

    International Nuclear Information System (INIS)

    The electrochemical behavior of Co(II) in urea-choline chloride-CoCl2 melt was investigated by cyclic voltammetry at 373 K. The results show that the reaction of Co(II) to Co is irreversible and it proceeds via a one-step two electrons transfer process. The diffusion coefficient of Co(II) was estimated to be 1.7 × 10−6 cm2 s−1 at 373 K. Electrodeposition of cobalt was studied at different cathodic potentials (-0.80 to -0.95 V) and at different temperatures (353 to 383 K) in eutectic mixture of choline chloride and urea (1:2 molar ratio). The deposits were characterized using scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). SEM images show that uniform, dense, and compact deposits were obtained at -0.80 V within a temperature range of 353 K to 373 K. EDS and XRD analysis confirm that high-purity metallic Co deposits were obtained

  14. The electrodeposition of lead from chloride electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A.

    1986-11-28

    At low current densities, lead was deposited onto a lead substrate as a fine powder that did not adhere well to the substrate. At higher current densities dendritic growth occurred. Lead does not adhere to a graphite substrate and, since copper and titanium substrates require higher cell voltages than lead substrates, these three substrates were rejected. The temperature of the electrolyte must be maintained above 69/sup 0/C to avoid the precipitation of lead chloride in the cell. Optimum current efficiencies at the anode and cathode were obtained at 80/sup 0/C, and no improvement in the morphology of the deposit was observed at higher temperatures. A combination of Quebracho extract and cuprous ions achieved the greatest improvement in the morphology of the deposit, while maintaining high current efficiencies at the anode and cathode. However, when the deposition time was increased, dendritic growth was much in evidence. A compact, adherent deposit of lead could not be obtained from chloride electrolytes. 22 refs., 21 figs., 11 tabs.

  15. Open cycle lithium chloride cooling system

    Science.gov (United States)

    Lenz, T. G.; Loef, G. O. G.; Iyer, R.; Wenger, J.

    1983-05-01

    A lithium chloride open cycle absorption chiller has been designed, built and tested. Solution reconcentration takes place in a small counter current packed column supplied with solar heated air. Removal of noncondensable gases that enter the chiller dissolved in the strong solution and the make-up refrigerant streams is accomplished by a liquid-jet ejector and a small vacuum pump. Cooling capacities approaching 1.4 tons and COP levels of 0.58 have been achieved at non-optimum operating conditions. Test results from preliminary system operation suggest that mass transfer processes in both the packed column reconcentrator and the absorber are controlled by concentration gradients in the lithium chloride solution. Liquid phase controlled mass transfer dictates an operating strategy different from the previously assumed gas phase controlled process to obtain maximum rates of evaporation in the packed column. Determination of optimal operating conditions leading to decreased electrical power consumption and improved cooling capacity and coefficient of performance will require further analysis and testing.

  16. Fault locator of an allyl chloride plant

    Directory of Open Access Journals (Sweden)

    Savković-Stevanović Jelenka B.

    2004-01-01

    Full Text Available Process safety analysis, which includes qualitative fault event identification, the relative frequency and event probability functions, as well as consequence analysis, was performed on an allye chloride plant. An event tree for fault diagnosis and cognitive reliability analysis, as well as a troubleshooting system, were developed. Fuzzy inductive reasoning illustrated the advantages compared to crisp inductive reasoning. A qualitative model forecast the future behavior of the system in the case of accident detection and then compared it with the actual measured data. A cognitive model including qualitative and quantitative information by fuzzy logic of the incident scenario was derived as a fault locator for an ally! chloride plant. The obtained results showed the successful application of cognitive dispersion modeling to process safety analysis. A fuzzy inductive reasoner illustrated good performance to discriminate between different types of malfunctions. This fault locator allowed risk analysis and the construction of a fault tolerant system. This study is the first report in the literature showing the cognitive reliability analysis method.

  17. 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...

  18. Regulation of Shaker-type potassium channels by hypoxia. Oxygen-sensitive K+ channels in PC12 cells.

    Science.gov (United States)

    Conforti, L; Millhorn, D E

    2000-01-01

    Little is known about the molecular composition of the O2-sensitive K+ (Ko2) channels. The possibility that these channels belong to the Shaker subfamily (Kv1) of voltage-dependent K+ (Kv) channels has been raised in pulmonary artery (PA) smooth muscle cells. Numerous findings suggest that the Ko2 channel in PC12 cells is a Kv1 channel, formed by the Kv1.2 alpha subunit. The Ko2 channel in PC12 cells is a slow-inactivating voltage-dependent K+ channel of 20 pS conductance. Other Kv channels, also expressed in PC12 cells, are not inhibited by hypoxia. Selective up-regulation by chronic hypoxia of the Kv1.2 alpha subunit expression correlates with an increase O2-sensitivity of the K+ current. Other Kv1 alpha subunit genes encoding slow-inactivating Kv channels, such as Kv1.3, Kv2.1, Kv3.1 and Kv3.2 are not modulated by chronic hypoxia. The Ko2 current in PC12 cells is blocked by 5 mM externally applied tetraethylammonium chloride (TEA) and by charydbotoxin (CTX). The responses of the Kv1.2 K+ channel to hypoxia have been studied in the Xenopus oocytes and compared to those of Kv2.1, also proposed as Ko2 channel in PA smooth muscle cells. Two-electrode voltage clamp experiments show that hypoxia induces inhibition of K+ current amplitude only in oocytes injected with Kv1.2 cRNA. These data indicate that Kv1.2 K+ channels are inhibited by hypoxia. PMID:10849667

  19. Estimation of trace chloride in nuclear grade sodium

    International Nuclear Information System (INIS)

    The author represents a method to determinate trace levels of chloride in sodium coolant in a fast neutron reactor. Vacuum distillation is used for separating chloride from sodium matrix. After separation, matrix interference from sodium salts is eliminated and a large sample amount can be taken for analysing chloride. In contrast with other similar mercuric thiocyanate colorimetric method in China, this method minimizes a glaring blank of colorimetric solution and determining influence of temperature. Therefore, it increases the precision in analysing chloride. The results of the research demonstrate that when a level of chloride in sodium is less than 1 μg/g, the precision is 37% (n = 10). The recoveries of chloride in high pure sodium demonstrate that when 15-30 μg/g of chloride is added in sodium, the recovery is 97.8%-98.6% and when 4μg/g of chloride is added, then the average recovery is 99.2%. And the relative standard deviation is 16.2% (n =7). It is demonstrated that a monitoring requirement of chloride can be satisfied with this method in coolant of sodium in a fast neutron reactor

  20. Interpretation of postmortem vitreous concentrations of sodium and chloride.

    Science.gov (United States)

    Zilg, B; Alkass, K; Berg, S; Druid, H

    2016-06-01

    Vitreous fluid can be used to analyze sodium and chloride levels in deceased persons, but it remains unclear to what extent such results can be used to diagnose antemortem sodium or chloride imbalances. In this study we present vitreous sodium and chloride levels from more than 3000 cases. We show that vitreous sodium and chloride levels both decrease with approximately 2.2mmol/L per day after death. Since potassium is a well-established marker for postmortem interval (PMI) and easily can be analyzed along with sodium and chloride, we have correlated sodium and chloride levels with the potassium levels and present postmortem reference ranges relative the potassium levels. We found that virtually all cases outside the reference range show signs of antemortem hypo- or hypernatremia. Vitreous sodium or chloride levels can be the only means to diagnose cases of water or salt intoxication, beer potomania or dehydration. We further show that postmortem vitreous sodium and chloride strongly correlate and in practice can be used interchangeably if analysis of one of the ions fails. It has been suggested that vitreous sodium and chloride levels can be used to diagnose drowning or to distinguish saltwater from freshwater drowning. Our results show that in cases of freshwater drowning, vitreous sodium levels are decreased, but that this mainly is an effect of postmortem diffusion between the eye and surrounding water rather than due to the drowning process, since the decrease in sodium levels correlates with immersion time. PMID:27105154

  1. Durability of cracked fibre reinforced concrete structures exposed to chlorides

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Ekman, Tom; Hansen, Kurt Kielsgaard

    Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by exposing beams to 4-point bending until a predefined crack width is reached, using a newly developed test setup. Exposure to a concentrated chloride solution is...... used as environmental load. The chloride penetration is characterized both qualitatively (UV-test) and quantitatively (chloride profile) and by microscopy. The test programme involves three different concrete qualities. Both steel fibres and polypropylene fibres are used in the concrete beams as well...... as main reinforcement. The effect of the cracks, the fibres and the concrete quality on the chloride penetration is studied....

  2. Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

    Directory of Open Access Journals (Sweden)

    Beixiao Zhang

    2010-08-01

    Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

  3. Influence of space between atmospheric channels and beams' number on scintillation

    Institute of Scientific and Technical Information of China (English)

    Weihui Liu (刘维慧); Jian Wu (吴健)

    2003-01-01

    On the basis of Kolmogorov's theorem, the physical meanings of beams' correlation function on received plane are extended. Approximate formula of channels' across correlation coefficient is deduced from multiple beams through atmosphere. And the scintillation variance of multiple beams is also induced. The result shows along with the channels close to one another, the correlation coefficient increases, and so does the scintillation variance. When the channels completely combine, the scintillation variance of multiple channels is with no difference from that of one channel.

  4. Unwrapping Closed Timelike Curves

    CERN Document Server

    Slobodov, Sergei

    2008-01-01

    Closed timelike curves (CTCs) appear in many solutions of the Einstein equation, even with reasonable matter sources. These solutions appear to violate causality and so are considered problematic. Since CTCs reflect the global properties of a spacetime, one can attempt to change its topology, without changing its geometry, in such a way that the former CTCs are no longer closed in the new spacetime. This procedure is informally known as unwrapping. However, changes in global identifications tend to lead to local effects, and unwrapping is no exception, as it introduces a special kind of singularity, called quasi-regular. This "unwrapping" singularity is similar to the string singularities. We give two examples of unwrapping of essentially 2+1 dimensional spacetimes with CTCs, the Gott spacetime and the Godel universe. We show that the unwrapped Gott spacetime, while singular, is at least devoid of CTCs. In contrast, the unwrapped Godel spacetime still contains CTCs through every point. A "multiple unwrapping"...

  5. Tarantula toxins interacting with voltage sensors in potassium channels

    OpenAIRE

    Swartz, Kenton J.

    2006-01-01

    Voltage-activated ion channels open and close in response to changes in membrane voltage, a process that is crucial for electrical signaling in the nervous system. The venom from many poisonous creatures contains a diverse array of small protein toxins that bind to voltage-activated channels and modify the gating mechanism. Hanatoxin and a growing number of related tarantula toxins have been shown to inhibit activation of voltage-activated potassium (Kv) channels by interacting with their vol...

  6. Coding for quantum channels with side information at the transmitter

    OpenAIRE

    Dupuis, Frédéric

    2008-01-01

    We consider the problem of coding for quantum channels with side information that is available ahead of time at the transmitter but not at the receiver. We find a single-letter expression for the entanglement-assisted quantum capacity of such channels which closely parallels Gel'fand and Pinsker's solution to the classical version of the same problem. This theorem can also be used to find a lower bound on the unassisted quantum capacity of these channels.

  7. Spiro-annulation of barbituric acid derivatives and its analogs by ring-closing metathesis reaction.

    Science.gov (United States)

    Kotha, Sambasivarao; Deb, Ashoke Chandra; Kumar, Ramanatham Vinod

    2005-02-15

    Barbituric acid 1 and related beta-dicarbonyl compounds were dialkenylated under the phase-transfer catalyst [e.g., benzyltriethylammonium chloride (BTEAC)] conditions to generate the diallylated products. These diallylated products were subjected to the ring-closing metathesis (RCM) reaction to deliver the corresponding spiro-annulated derivatives. PMID:15686908

  8. Nonrelativistic closed string theory

    OpenAIRE

    Gomis, Jaume; Ooguri, Hirosi

    2001-01-01

    We construct a Galilean invariant nongravitational closed string theory whose excitations satisfy a nonrelativistic dispersion relation. This theory can be obtained by taking a consistent low energy limit of any of the conventional string theories, including the heterotic string. We give a finite first order worldsheet Hamiltonian for this theory and show that this string theory has a sensible perturbative expansion, interesting high energy behavior of scattering amplitudes and a Hagedorn tra...

  9. Correction of chloride transport and mislocalization of CFTR protein by vardenafil in the gastrointestinal tract of cystic fibrosis mice.

    Directory of Open Access Journals (Sweden)

    Barbara Dhooghe

    Full Text Available Although lung disease is the major cause of mortality in cystic fibrosis (CF, gastrointestinal (GI manifestations are the first hallmarks in 15-20% of affected newborns presenting with meconium ileus, and remain major causes of morbidity throughout life. We have previously shown that cGMP-dependent phosphodiesterase type 5 (PDE5 inhibitors rescue defective CF Transmembrane conductance Regulator (CFTR-dependent chloride transport across the mouse CF nasal mucosa. Using F508del-CF mice, we examined the transrectal potential difference 1 hour after intraperitoneal injection of the PDE5 inhibitor vardenafil or saline to assess the amiloride-sensitive sodium transport and the chloride gradient and forskolin-dependent chloride transport across the GI tract. In the same conditions, we performed immunohistostaining studies in distal colon to investigate CFTR expression and localization. F508del-CF mice displayed increased sodium transport and reduced chloride transport compared to their wild-type littermates. Vardenafil, applied at a human therapeutic dose (0.14 mg/kg used to treat erectile dysfunction, increased chloride transport in F508del-CF mice. No effect on sodium transport was detected. In crypt colonocytes of wild-type mice, the immunofluorescence CFTR signal was mostly detected in the apical cell compartment. In F508del-CF mice, a 25% reduced signal was observed, located mostly in the subapical region. Vardenafil increased the peak of intensity of the fluorescence CFTR signal in F508del-CF mice and displaced it towards the apical cell compartment. Our findings point out the intestinal mucosa as a valuable tissue to study CFTR transport function and localization and to evaluate efficacy of therapeutic strategies in CF. From our data we conclude that vardenafil mediates potentiation of the CFTR chloride channel and corrects mislocalization of the mutant protein. The study provides compelling support for targeting the cGMP signaling pathway in CF

  10. 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...

  11. 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)

  12. 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.

  13. 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.

  14. A 0-Memory Model for Single Ion Channel

    Institute of Scientific and Technical Information of China (English)

    Zhou Wenqing; Fan Jiqian; Guan Yongyuan

    1998-01-01

    This paper discusses a 0-memory model for a single ion channel. The renewal rates of the open-class and the close-class are proposed to deseribe kinetic properties of a single ion channel. Further more, a procedure to estimate the parameters in the model is suggested and illustrated with examples in pharmacology.

  15. A Micromechanical RF Channelizer

    Science.gov (United States)

    Akgul, Mehmet

    insertion loss by 1.8 dB and yields the desired equiripple passband shape. An electrical equivalent circuit is presented that captures not only the ideal filter response, but also parasitic non-idealities that create electrical feed-through, where simulation of the derived equivalent circuit matches the measured filter spectrum closely both in-band and out-of-band. The combined 2.7dB passband insertion loss and 50dB stopband rejection of the demonstrated 206-element 0.09% bandwidth 223.4-MHz differential micromechanical disk filter represents a landmark for capacitive-gap transduced micromechanical resonator technology. This demonstration proves that the mere introduction of small gaps, on the order of 39 nm, goes a long way towards moving this technology from a research curiosity to practical performance specs commensurate with the needs of actual RF channel-selecting receiver front-ends. It also emphasizes the need for tuning and defensive stress-relieving structural design when percent bandwidths and gaps shrink, all demonstrated by the work herein. Perhaps most encouraging is that the models presented in dissertation used to design the filter and predict its behavior seem to be all be spot on. This means that predictions using these models foretelling 1-GHz filters with sub-200O impedances enabled by 20nm-gaps might soon come true, bringing this technology ever closer to someday realizing the ultra-low power channel-selecting communication front-ends targeted for autonomous set-and-forget sensor networks. Work towards these goals continues.

  16. Discrete stochastic modeling of calcium channel dynamics

    CERN Document Server

    Baer, M E; Levine, H; Tsimring, L S; Baer, Markus; Falcke, Martin; Levine, Herbert; Tsimring, Lev S.

    1999-01-01

    We propose a simple discrete stochastic model for calcium dynamics in living cells. Specifically, the calcium concentration distribution is assumed to give rise to a set of probabilities for the opening/closing of channels which release calcium thereby changing those probabilities. We study this model in one dimension, analytically in the mean-field limit of large number of channels per site N, and numerically for small N. As the number of channels per site is increased, the transition from a non-propagating region of activity to a propagating one changes in nature from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state, in a parameter range where the limiting deterministic model exhibits only single pulse propagation.

  17. Discrete Stochastic Modeling of Calcium Channel Dynamics

    International Nuclear Information System (INIS)

    We propose a discrete stochastic model for calcium dynamics in living cells. A set of probabilities for the opening/closing of calcium channels is assumed to depend on the calcium concentration. We study this model in one dimension, analytically in the limit of a large number of channels per site N , and numerically for small N . As the number of channels per site is increased, the transition from a nonpropagating region of activity to a propagating one changes from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state. (c) 2000 The American Physical Society

  18. Sodium and chloride levels in rainfall, mist, streamwater and groundwater at the Plynlimon catchments, mid-Wales: inferences on hydrological and chemical controls

    Directory of Open Access Journals (Sweden)

    C. Neal

    2000-01-01

    Full Text Available Variations in sodium and chloride in atmospheric inputs (rainfall and mist, stream runoff and groundwater stores are documented for the upper Severn River (Afon Hafren and Afon Hore catchments, Plynlimon, mid-Wales. The results show five salient features. Sodium and chloride concentrations are highly variable and highly correlated in rainfall and mist. The sodium-chloride relationship in rainfall has a slope close to the sodium/chloride ratio in sea-water, and an intercept that is not significantly different from zero. This indicates that sea-salt is the dominant source of both sodium and chloride in rainfall, which would be expected given the maritime nature of the metrology. For mist, there is also a straight line with near-zero intercept, but with a slightly higher gradient than the sea-salt ratio, presumably due to small additional sodium inputs from other sources. There is an approximate input-output balance for both sodium and chloride, with the exception of one groundwater well, in which high chemical weathering results in an anomalous high Na/Cl ratio. Thus, atmospheric deposition is the dominant source of both sodium and chloride in groundwater and streamflow. The fluctuations in sodium and chloride concentrations in the streams and groundwaters are strongly damped compared to those in the rain and the mist, reflecting the storage and mixing of waters in the subsurface. On all timescales, from weeks to years, sodium fluctuations are more strongly damped than chloride fluctuations in streamflow. The additional damping of sodium is consistent with ion exchange buffering of sodium in the catchment soils.  Sodium and chloride concentrations are linearly correlated in the streams and groundwaters, but the slope is almost universally less than the sea-salt ratio and there is a non-zero intercept. The Na/Cl ratio in streamflow and groundwater is higher than the sea-salt ratio when salinity is low and lower than the sea-salt ratio when

  19. Effect of application of ammonium chloride and calcium chloride on alfalfa cation-anion content and yield.

    Science.gov (United States)

    Goff, J P; Brummer, E C; Henning, S J; Doorenbos, R K; Horst, R L

    2007-11-01

    A major factor predisposing the cow to periparturient hypocalcemia, or milk fever, is being fed a prepartum ration with a high dietary cation-anion difference (DCAD). The DCAD can be favorably altered to prevent milk fever by decreasing K and Na or increasing Cl and S in forages for cows in late gestation. The objective of this study was to test the hypothesis that application of Cl to alfalfa could increase Cl in forage, thereby lowering DCAD. We conducted a field experiment at 2 Iowa locations in which established plots of alfalfa were treated in April 2001 with 0, 56, 112, or 168 kg of Cl/ha using ammonium chloride, calcium chloride, or a mix of the 2 sources with equal amounts of chloride coming from each source. Plots were harvested 4 times in 2001 and once in 2002 and plant tissue analyzed for mineral composition. Applying chloride from either source once in the spring resulted in increased plant chloride content over all 4 cuttings for that year. Averaged across both locations, chloride levels were elevated from 0.52% in control plots to 0.77, 0.87, and 0.89% Cl in plots treated with 56, 112, and 168 kg of Cl/ha, respectively. Chloride application had no effect on plant potassium, sodium, calcium, magnesium, or phosphorus. These results suggest chloride application can elevate chloride content and lower DCAD values of alfalfa, and also maintain crop yield. PMID:17954756

  20. THE COMPATIBILITY OF BLENDS OF POLY(VINYL CHLORIDE) OR CHLORINATED POLY(VINYL CHLORIDE) WITH POLY(METHYL METHACRYLATE)

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; CHENG Rongshi

    1988-01-01

    IR spectral shifts of carbonyl vibrational absorption for ethyl acetate, which acts analogically as the structural unit of poly(methyl methacrylate), in cyclohexane, chloroform, chlorinated paraffins, poly(vinyl chloride) and chlorinated poly(vinyl chloride) were measured. The results suggest that there are specific interactions between the carbonyl groups and the chlorinated hydrocarbons which could be responsible for the apparent compatibility of poly(vinyl chloride) -poly(methyl methacrylate) and chlorinated poly(vinyl chloride) -poly(methyl methacrylate) blends. Additionally, the effects of the preparation mode of blend films on phase separation and observed compatibility are discussed.

  1. 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.

  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. Closed strings from nothing

    OpenAIRE

    Kleban, Matthew; Lawrence, Albion; Shenker, Stephen

    2000-01-01

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet bo...

  4. Closed Circuit Videoinstallationen

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    and 650 artists. This and the notes on further reading and viewing will enable deeper explorations of the material in a way not unlike the open “hyper-text”- structure. Video technique makes it possible to simultaneously record and reproduce images, sound and sequences of motion; that potential can...... and at the same time general investigations. The research project, ‘Closed-Circuit-Video Installations. A Study on the History and Theory of Media Art’, is being supported by the Fritz-Thyssen Foundation, Cologne....

  5. Aspects of the magnetism of ferrous chloride

    International Nuclear Information System (INIS)

    This work is a critical review of the existing work on ferrous chloride and presents, as well, a number of new experimental results. First, a careful analysis of the level structure of ferrous ions in the crystalline field shows that the crystalline anisotropy is of the same order of magnitude as the exchange interactions, a feature which gives rise to some particular effects, such as an upward curvature of the magnetization curve at 0 K in a perpendicular magnetic field. Further, the very low temperature (T > 0.4 K) thermal variation of both the specific heat and magnetic susceptibility evidences a magnetic component in elementary excitations. This result suggests the presence of a large magneto-elastic coupling. Finally, an experimental study of the H-T phase diagram near TN and of the critical behaviour of the specific heat and parallel susceptibility was performed. (author)

  6. Phosphates behaviours in conversion of FP chlorides

    International Nuclear Information System (INIS)

    The spent electrolyte of the pyroprocessing by metal electrorefining method should be considered for recycling after removal of fission products (FP) such as, alkali metals (AL), alkaline earth metals (ALE), and/or rare earth elements (REE), to reduce the volume of high-level radioactive waste. Among the various methods suggested for this purpose is precipitation by converting FP from chlorides to phosphates. Authors have been carrying out the theoretical analysis and experiment showing the behaviours of phosphate precipitates so as to estimate the feasibility of this method. From acquired results, it was found that AL except lithium and ALE are unlikely to form phosphate precipitates. However their conversion behaviours including REE were compatible with the theoretical analysis; in the case of LaPO4 as one of the REE precipitates, submicron-size particles could be observed while that of Li3PO4 was larger; the precipitates were apt to grow larger at higher temperature; etc.

  7. Estimating the chloride transport in cement paste

    Directory of Open Access Journals (Sweden)

    Princigallo, A.

    2012-06-01

    Full Text Available A method was developed to measure the diffusion coefficient of chloride ions in cement paste based on an analytical solution to Fick’s 2nd law in a cylindrical coordinate system. This natural method yielded diffusivity results within as little as a month. Testing time was reduced by exploiting the three-dimensional inward flux in the specimen. In an attempt to determine the saturation concentration, dense portland cement pastes were exposed to a concentrated chloride solution. The method proved to be useful for exploring cement hydration-induced changes in the diffusion coefficient of cement paste.

    Se ha desarrollado un método para medir el coeficiente de difusión de los iones cloruro en la pasta de cemento, partiendo de una aplicación analítica de la segunda ley de Fick en un sistema de coordinadas cilíndrico. Este método, que es natural, demostró ser capaz de producir resultados de difusividad en tan solo un mes. Se consiguió reducir el tiempo de ensayo mediante el aprovechamiento de la tridimensionalidad del flujo desde el exterior al interior de la probeta. A fin de determinar la concentración de saturación, se sometieron las pastas de cemento Portland a una disolución de cloruros concentrada. Este método resultó ser útil en el estudio de los cambios del coeficiente de difusión de la pasta de cemento provocados por las reacciones de hidratación que tienen lugar en esta.

  8. TRANSITIONS IN ELECTROCHEMICAL NOISE DURING PITTING CORROSION OF ALUMINUM IN CHLORIDE ENVIRONMENTS

    International Nuclear Information System (INIS)

    Aluminum, in a chloride containing solutions close to its pitting potential, shows vigorous fluctuations in current and potential. Measurements have been made of the freely corroding potential, and the currents between interconnected electrodes. It is shown that there is a transition in the behavior of the transients. The transition occurs when multiple active pits are present and electrochemical communication occurs between them. The major source of current and potential transients is the growth process in the active pits rather than meta-stable pitting at the passive surface

  9. Coordination compounds of transition metal chlorides with tetrazoles

    International Nuclear Information System (INIS)

    Coordination compounds (CC) of Co(2), Ni(2), Cu(2), Cd(2) chlorides with tetrazole and Ni(2) and Cd(2) chloride CC with tetrazolylhydrazone benzaldehyde are synthesized. The compounds are characterized by electron- and IR-spectroscopy, magnetic measurements (78-300 K), radiography. Conclusions are made on polynuclear structure of coordination compounds and Msup((2)) octahedron coordination

  10. Microwave Mapping Demonstration Using the Thermochromic Cobalt Chloride Equilibrium

    Science.gov (United States)

    Nguyen, Vu D.; Birdwhistell, Kurt R.

    2014-01-01

    An update to the thermochromic cobalt(II) chloride equilibrium demonstration is described. Filter paper that has been saturated with aqueous cobalt(II) chloride is heated for seconds in a microwave oven, producing a color change. The resulting pink and blue map is used to colorfully demonstrate Le Châtelier's principle and to illuminate the…

  11. Probabilistic Models and Computational Methods for Chloride Ingress in Concrete

    DEFF Research Database (Denmark)

    Engelund, S.

    Within the last decades it has been recognized that reinforced concrete structures are subject to a number of destructive mechanisms which might affect the structure in such a way that it is not able to fulfil its purpose efficiently. The present report focuses on chloride ingress and chloride-in...

  12. Prostaglandin synthetase inhibitor in an infant with congenital chloride diarrhoea.

    OpenAIRE

    Minford, A M; Barr, D G

    1980-01-01

    Hyper-reninaemia, hypokaluria, and hypokalaemia in an infant with congenital chloride diarrhoea improved during treatment with a prostaglandin synthetase inhibitor, ketoprofen. There was evidence of increased activity of therenin-aldosterone system when ketoprofen was stopped. It is suggested that prostaglandins may be involved in stimulating the renin-aldosterone system in congenital chloride diarrhoea.

  13. Chlorides behavior in raw fly ash washing experiments

    International Nuclear Information System (INIS)

    Chloride in fly ash from municipal solid waste incinerators (MSWIs) is one of the obstructive substances in recycling fly ash as building materials. As a result, we have to understand the behavior of chlorides in recycling process, such as washing. In this study, we used X-ray absorption near edge structure (XANES) and X-ray diffraction (XRD) to study the chloride behavior in washed residue of raw fly ash (RFA). We found that a combination of XRD and XANES, which is to use XRD to identify the situation of some compounds first and then process XANES data, was an effective way to explain the chlorides behavior in washing process. Approximately 15% of the chlorine in RFA was in the form of NaCl, 10% was in the form of KCl, 51% was CaCl2, and the remainder was in the form of Friedel's salt. In washing experiments not only the mole percentage but also the amount of soluble chlorides including NaCl, KCl and CaCl2 decreases quickly with the increase of liquid to solid (L/S) ratio or washing frequency. However, those of insoluble chlorides decrease slower. Moreover, Friedel's salt and its related compound (11CaO.7Al2O3.CaCl2) were reliable standards for the insoluble chlorides in RFA, which are strongly related to CaCl2. Washing of RFA promoted the release of insoluble chlorides, most of which were in the form of CaCl2.

  14. Stability constants of the Europium complexes with the chloride ions

    International Nuclear Information System (INIS)

    The stability constants of lanthanides complexes with chloride ions which were determined at the same ionic force but in different media, are significantly different. It does not exist a systematic study over these stability constants. The purpose of this work is to determine the stability constants of the europium complexes with chloride ions at 303 K, by the solvents extraction method. (Author)

  15. Monte Carlo calculation of chloride diffusion in concrete

    International Nuclear Information System (INIS)

    Coefficient of chloride diffusion is calculated by applying the Fick's second law of diffusion to a chloride concentration profile. Then from the signal strength for various chlorine gamma-ray energies was then calculated at the detector of the portable D-D neutron generator based PGNAA setup. (author)

  16. Closed strings from nothing

    International Nuclear Information System (INIS)

    We study the physics of open strings in bosonic and type-II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori, and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and world sheet boundary renormalization group flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge it appears to have light, weakly coupled open strings existing in the core. We argue that the flux tube acquires a size of order α' through sigma model and string coupling effects, and that confinement effects make the light degrees of freedom heavy and strongly interacting

  17. Closed Strings From Nothing

    International Nuclear Information System (INIS)

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order α' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting

  18. Stability of few layer graphene films doped with gold (III) chloride

    Science.gov (United States)

    Abdullah-Al-Galib, Mir; Hou, Bo; Shahriad, Tahmeed; Zivanovic, Sandra; Radadia, Adarsh D.

    2016-03-01

    In this paper we study the stability of few layer graphene (5-7 layers) doped with gold nanoparticles through spin coating of a gold (III) chloride solution. Specifically sheet resistance, optical transmittance and surface morphology were monitored over a period of four weeks. Through scanning electron microscopy we observed that the gold nanoparticles of 29.1 ± 1.3 nm diameters, which were formed on surfaces freshly doped with a 20 mM solution, agglomerate and fuse over the period of four weeks into larger particles of 50-110 nm diameters. At the end of four weeks of aging, regardless in air or vacuum, the optical transmittance at 550 nm for the doped samples resumed a value close to that of undoped samples. During these four weeks, the sheet resistances of the samples doped with 20 mM gold chloride also increased from 130 ohm/sq to 300 ohm/sq, but stayed comparable to indium tin oxide. In summary, despite the instability of doped FLG surfaces obtained using gold (III) chloride solutions, this study warrants the use of doped FLG films for building the next generation photovoltaics.

  19. 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.

  20. 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.

  1. 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

  2. 2-(Furan-2-yl-1,3-bis(furan-2-ylmethyl-1H-benzimidazol-3-ium chloride monohydrate

    Directory of Open Access Journals (Sweden)

    David K. Geiger

    2012-10-01

    Full Text Available The title hydrated salt, C21H17N2O3+·Cl−·H2O, exhibits disorder in one of the furan rings. The major and minor components have a refined occupancy ratio of 0.844 (19:0.156 (19. The structure displays intermolecular hydrogen bonding involving the water molecule and the chloride anion. Close intermolecular C—H...Cl and C—H...(furan ring interactions complete the hydrogen bonding.

  3. Pourbaix Diagrams for Copper in 5 m Chloride Solution

    International Nuclear Information System (INIS)

    Pourbaix diagrams for the copper in 5 molal chlorine at 5-100 deg C have been calculated. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of dissolved copper, 10-4 and 10-6 molal, have been used in the calculations. ChIoride is the predominating chlorine species in aqueous solutions. Therefore Pourbaix diagrams for chlorine can be used to discuss the effect of chloride solutions on the corrosion behavior of a metal. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. Copper corrodes in 5 molal chloride by formation Of CuCl32- in acid and alkaline solutions. At higher potentials in acid solutions CuCl32- is oxidized to CuCl2(aq), which at increasing potentials can form CuCI+, Cu2+ or CuClO3+. Copper passivates by formation of Cu2O(cr), CuO(cr), or CUO2 3 Cu(OH)2(s). Cu2O(cr) does not form at [Cu(aq)]tot = 10-6 molal in 5 m C1-, which results in a corrosion area between the immunity and passivity areas. Copper at the anticipated repository potentials and pH corrodes at 100 deg C at [Cu(aq)]tot = 10-4 molal and at 80-100 deg C at [Cu(aq)]tot = 10-6 molal. Copper at the anticipated repository potentials and pH can corrode at 80 deg C at [Cu(aq)]tot = 10-4 molal and at 50 deg C at [Cu(aq)]tot = 10-6 molal. The bentonite clay and copper canisters in the deep repository can be considered as a 'closed' system from macroscopic point of view. The clay barrier limits both inward diffusion of oxygen and aggressive anions as well as outward diffusion of corrosion products from the canisters. Both diffusion phenomena will drive the corrosion potential into the immunity area of the Pourbaix diagram for copper. The corrosion will thereby stop by an automatic mechanism. However, this is only valid if no macro cracks occur in the clay. The auto-stop is valid for the initial, main and cooling phases. During a glacial

  4. Science policy up close

    CERN Document Server

    Marburger, John H

    2015-01-01

    In a career that included tenures as president of Stony Brook University, director of Brookhaven National Laboratory, and science advisor to President George W. Bush, John Marburger (1941 2011) found himself on the front line of battles that pulled science ever deeper into the political arena. From nuclear power to global warming and stem cell research, science controversies, he discovered, are never just about science. Science Policy Up Close" presents Marburger s reflections on the challenges science administrators face in the twenty-first century. In each phase of public service Marburger came into contact with a new dimension of science policy. The Shoreham Commission exposed him to the problem of handling a volatile public controversy over nuclear power. The Superconducting Super Collider episode gave him insights into the collision between government requirements and scientists expectations and feelings of entitlement. The Directorship of Brookhaven taught him how to talk to the public about the risks ...

  5. Vortices on closed surfaces

    CERN Document Server

    Boatto, Stefanella

    2008-01-01

    We consider $N$ point vortices $s_j$ of strengths $\\kappa_j$ moving on a closed (compact, boundaryless, orientable) surface $S$ with riemannian metric $g$. As far as we know, only the sphere or surfaces of revolution, the latter qualitatively, have been treated in the available literature. The aim of this note is to present an intrinsic geometric formulation for the general case. We give a simple proof of Kimura's conjecture that a dipole describes geodesic motion. Searching for integrable vortex pairs systems on Liouville surfaces is in order. The vortex pair system on a triaxial ellipsoid extends Jacobi's geodesics. Is it Arnold-Liouville integrable? Not in our wildest dreams is another possibility: that quantizing a vortex system could relate with a million dollars worth question, but we took courage - nerve is more like it - to also present it.

  6. Calcium homeostasis modulator (CALHM) ion channels.

    Science.gov (United States)

    Ma, Zhongming; Tanis, Jessica E; Taruno, Akiyuki; Foskett, J Kevin

    2016-03-01

    Calcium homeostasis modulator 1 (CALHM1), formerly known as FAM26C, was recently identified as a physiologically important plasma membrane ion channel. CALHM1 and its Caenorhabditis elegans homolog, CLHM-1, are regulated by membrane voltage and extracellular Ca(2+) concentration ([Ca(2+)]o). In the presence of physiological [Ca(2+)]o (∼1.5 mM), CALHM1 and CLHM-1 are closed at resting membrane potentials but can be opened by strong depolarizations. Reducing [Ca(2+)]o increases channel open probability, enabling channel activation at negative membrane potentials. Together, voltage and Ca(2+) o allosterically regulate CALHM channel gating. Through convergent evolution, CALHM has structural features that are reminiscent of connexins and pannexins/innexins/LRRC8 (volume-regulated anion channel (VRAC)) gene families, including four transmembrane helices with cytoplasmic amino and carboxyl termini. A CALHM1 channel is a hexamer of CALHM1 monomers with a functional pore diameter of ∼14 Å. CALHM channels discriminate poorly among cations and anions, with signaling molecules including Ca(2+) and ATP able to permeate through its pore. CALHM1 is expressed in the brain where it plays an important role in cortical neuron excitability induced by low [Ca(2+)]o and in type II taste bud cells in the tongue that sense sweet, bitter, and umami tastes where it functions as an essential ATP release channel to mediate nonsynaptic neurotransmitter release. CLHM-1 is expressed in C. elegans sensory neurons and body wall muscles, and its genetic deletion causes locomotion defects. Thus, CALHM is a voltage- and Ca(2+) o-gated ion channel, permeable to large cations and anions, that plays important roles in physiology. PMID:26603282

  7. 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

  8. Channel Norm-Based User Scheduling Exploiting Channel Asymmetry in Base Station Cooperative Transmission Systems

    CERN Document Server

    Han, Shengqian; Bengtsson, Mats

    2010-01-01

    Base station cooperative transmission, which is also known as coordinated multi-point (CoMP) transmission, is a promising technique to improve spectrum efficiency in future cellular systems. However, they need large signalling overhead to gather the channel information. In this paper, we consider low feedback user scheduling in downlink coherent CoMP systems exploiting their inherent channel asymmetry. Through the analysis of the statistics of the angle between channel vectors and the tightness of a lower bound of the orthogonally projected norm, we show that channel norm provides sufficient information to judge the orthogonality among users in asymmetric channels. Based on this observation, we propose a channel norm-based user scheduler (NUS), a local channel aided NUS (LocalNUS) and a large-scale fading-based user scheduler (LUS). Simulation results show that the LocalNUS performs very close to the existing greedy user scheduler (GUS) and semi-orthogonal user scheduler (SUS) with full channel state informat...

  9. Aloe Vera Extract Effect on Sperm Quality and Testicular Tissue of Rats Induced by Cadmium Chloride

    Directory of Open Access Journals (Sweden)

    F Farhangdoost

    2014-04-01

    Full Text Available Background & aim: A lot of physical and chemical factors cause infertility disorders. Cadmium is a chemical agent which damages the cell structure of the reproductive system. For reducing the effects of various factors, new traditional methods have been used. The aim of this study was to investigate the effects of Aloe vera extract on testicular tissue of rats induced by cadmium chloride. Methods: In this experimental study, 40 male Wistar rats (180-200 gr were randomly divided into four groups. Groups 1 and 2 received Cadmium chloride (1/5 mg / kg/ IP. Mice induced by cadmium chloride were treated with Aloe vera. Control and normal rats were treated with 400 mg/kg of Aloe vera extracts. After 25 days, these rats were weighed and then anesthetized using ether. Blood samples were collected from each individual to assess the level of testosterone and then the animals were debriefed. The testes were removed and transferred to 10% formalin solution. After tissue processing, 5 micron sections were prepared and stained with heamatoxillin-eosin and investigated by light microscope. Data were analyzed by one-way ANOVA test. Results: Mean seminiferous tubular diameter, number of spermatogonia, Leydig and Sertoli cell of cadmium control group compared to the healthy control group showed a significant decrease (p<0.05. The mean sperm count and sperm motility in extract cadmium group and healthy control group was close to normal and displayed a significant difference (p< 0.05. Conclusion: Hydroalcoholic extract of Aloe vera increases the number of spermatogonia, Leydig and Sertoli testicular tissue of mice contaminated with cadmium chloride

  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. Metal chloride precursor synthesization of Cu{sub 2}ZnSnS{sub 4} solar cell materials

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Min-Yen; Huang, Yu-Fong; Huang, Cheng-Liang; Yang, Chyi-Da [National Kaohsiung Marine University, Kaohsiung, Taiwan (China); Wuu, Dong-Sing [National Chung Hsing University, Taichung, Taiwan (China); Lei, Po-Hsun [National Formosa University, Yunlin, Taiwan (China)

    2014-07-15

    Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films with kesterite structures were prepared by directly sol-gel synthesizing spin-coated precursors on soda-lime-glass (SLG) substrates. The CZTS precursors were prepared by using solutions of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea. The ratio of SnCl{sub 4} in the precursors was found to play a critical role in the synthesization of CZTS. CZTS phases of SnS and SnS{sub 2} were observed in the synthesized films as prepared using precursors with a close to stoichiometric ratio of CuCl{sub 2}:ZnCl{sub 2}:SnCl{sub 4}:CH{sub 4}N{sub 2}S = 4:1:1:8, where SnCl{sub 4} was 1 mol/l. The amounts of the educed SnS and SnS{sub 2} phases observed in the SEM images could be readily reduced by decreasing the volume of SnCl{sub 4} in the mixed solution. With decreasing amount of SnCl{sub 4} from 1 mol/l, the as prepared CZTS reveals a significant improvement in its crystalline properties. In this work, CZTS with an average absorption coefficient and an optical energy gap of over 10{sup 4} cm{sup -1} and ∼1.5 eV, respectively, was obtained using precursors of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea mixed in a ratio of 2:1:0.25:8, and it had good crystallinity revealing a Cu-poor composition.

  13. A Study of Channel Estimation for OFDM WLAN System

    Institute of Scientific and Technical Information of China (English)

    CAOXuehong

    2005-01-01

    This paper addresses two important issues in channel estimation for OFDM system: the selection of the pilot tones and the interpolation methods. We first obtain the minimum number and the optimal position sets of the pilot tones, and the MSE bound of the channel estimation. Then two special schemes of channel estimate for IEEE802.11a WLAN system are proposed, which are named as LS method and interpolation method. We compare the performance by measuring MSE of the channel estimate and BER with BPSK, QPSK and 16QAM as uncoded OFDM modulations. The simulation results show that these two proposed schemes are pretty good especially for interpolation method. The MSE of these estimations are close to the bound, and the BER performance of uncoded system is very close to the case with known channel response.

  14. 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

  15. 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...

  16. 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...

  17. 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

  18. Communication channels between SKI and parliamentarians

    International Nuclear Information System (INIS)

    This document deals with the communication channels between SKI (Swedish Nuclear Power Inspectorate) and parliamentarians. SKI is meant to supervise the safety of Swedish nuclear installations and is legally required to report to the public with openness. They do not take part in the Nuclear debate and their only contact with parliamentarians consists in giving them background material on nuclear safety, the channels used being yearly Status Reports on this subject. Contacts between SKI and municipalities concerning nuclear utilities are close and include information materials, meetings, seminars and so on. (TEC)

  19. Ion Channels Involved in Cell Volume Regulation

    DEFF Research Database (Denmark)

    Hoffmann, Else Kay

    2011-01-01

    This mini review outlines studies of cell volume regulation in two closely related mammalian cell lines: nonadherent Ehrlich ascites tumour cells (EATC) and adherent Ehrlich Lettre ascites (ELA) cells. Focus is on the regulatory volume decrease (RVD) that occurs after cell swelling, the volume...... regulatory ion channels involved, and the mechanisms (cellular signalling pathways) that regulate these channels. Finally, I shall also briefly review current investigations in these two cell lines that focuses on how changes in cell volume can regulate cell functions such as cell migration, proliferation...

  20. Physiology of Epithelial Chloride and Fluid Secretion

    OpenAIRE

    Frizzell, Raymond A.; Hanrahan, John W.

    2012-01-01

    Epithelial salt and water secretion serves a variety of functions in different organ systems, such as the airways, intestines, pancreas, and salivary glands. In cystic fibrosis (CF), the volume and/or composition of secreted luminal fluids are compromised owing to mutations in the gene encoding CFTR, the apical membrane anion channel that is responsible for salt secretion in response to cAMP/PKA stimulation. This article examines CFTR and related cellular transport processes that underlie epi...

  1. 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.

  2. Caesium-137 Chloride Retention following Accidental Ingestion

    International Nuclear Information System (INIS)

    Four men became contaminated with caesium-137 chloride due to leaks in a 100 c source. The source was believed to be completely leak proof, since the caesium chloride was contained in a welded stainless-steel capsule which was covered with an outer steel jacket of standard Oak Ridge design. Most of the contamination occurred while the men were cleaning the components of a pneumatic device used to move the source. The most heavily- contaminated individual placed his mouth over the end of a transport tube and attempted to blow some ''dust'' out of the tube. The other men handled various parts of the transport mechanism and wiped ''dust'' out of holes with their fingers. None of the men washed their hands before eating lunch. When radioactive contamination was discovered on the following day, immediate efforts were made to decontaminate the men. Arrangements for whole-body counts were also made and, on the fifth day following contamination, the men reported to the Radiation Exposure Evaluation laboratory. The body burdens on the fifth day ranged from 35 - 970 nc of caesium-137. During the next five to six days the burdens dropped rapidly and on the eleventh day ranged from 28- 780 nc. After the eleventh day the body burdens of caesium-137 changed much more slowly. Whole-body counts made between the 11th and 160th day yielded biological half-lives of 76, 95 and 126 d for the three most heavily-contaminated individuals. During the period of rapid excretion all urine and faeces were collected and counted. These counts indicated a considerable superficial contamination prior to the eleventh day since only a portion of the removed caesium-137 was found in the urine and stool specimens. The body burdens of the four men are compared with normals of the same size, build, age and diet habits. A short discussion of normal burdens is included. A brief description of the counting system, data handling techniques and calibration procedures is also included. (author)

  3. The closed fuel cycle

    International Nuclear Information System (INIS)

    Available in abstract form only. Full text of publication follows: The fast growth of the world's economy coupled with the need for optimizing use of natural resources, for energy security and for climate change mitigation make energy supply one of the 21. century most daring challenges. The high reliability and efficiency of nuclear energy, its competitiveness in an energy market undergoing a new oil shock are as many factors in favor of the 'renaissance' of this greenhouse gas free energy. Over 160,000 tHM of LWR1 and AGR2 Used Nuclear Fuel (UNF) have already been unloaded from the reactor cores corresponding to 7,000 tons discharged per year worldwide. By 2030, this amount could exceed 400,000 tHM and annual unloading 14,000 tHM/year. AREVA believes that closing the nuclear fuel cycle through the treatment and recycling of Used Nuclear Fuel sustains the worldwide nuclear power expansion. It is an economically sound and environmentally responsible choice, based on the preservation of natural resources through the recycling of used fuel. It furthermore provides a safe and secure management of wastes while significantly minimizing the burden left to future generations. (authors)

  4. Ganymede - close up photos

    Science.gov (United States)

    1979-01-01

    Two close-up photos of Ganymede, largest of Jupiter's 13 moons, were obtained on July 8 by Voyager 2 from 86,000 miles (top) and 192,000 miles. They show different views of the largest block of dark, heavily cratered terrain seen on the giant moon. The bottom image shows objects three to four miles across; has a resolution of about 1.5 miles. The light, linear stripes recurring across the dark region resemble the outer rings of the large ring structure on Callisto. If these features are in fact related to an ancient ring structure formed by a large impact, their small curvature suggests that the original structure was even larger than one seen on Callisto. There is no apparent trace now of the center of this suggested structure, which must have been destroyed by the resurfacing evident over most of Ganymede in the grooved terrain. Another interpretation is that these features are not impact-related rings but are internally produced fractures crossing the dark terrain, similar to the grooved bands.

  5. NEXAFS and XPS studies of nitrosyl chloride.

    Science.gov (United States)

    Schio, Luca; Li, Cui; Monti, Susanna; Salén, Peter; Yatsyna, Vasyl; Feifel, Raimund; Alagia, Michele; Richter, Robert; Falcinelli, Stefano; Stranges, Stefano; Zhaunerchyk, Vitali; Carravetta, Vincenzo

    2015-04-14

    The electronic structure of nitrosyl chloride (ClNO) has been investigated in the gas phase by X-ray Photoelectron (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy at the Cl 2p, Cl 2s, N 1s and O 1s edges in a combined experimental and theoretical study. The theoretical calculations at different levels of approximation predict ionization potential values in good agreement with the experimental data and allow us to assign the main features of the absorption spectra. An unexpected failure of the density functional model is, however, observed in the calculation of the Cl 2s binding energy, which is related to a large self-interaction error. Largely different photoabsorption cross-section patterns are experimentally observed in core excitations from the investigated quantum shells (n = 1, 2). This finding is confirmed by the oscillator strength distributions calculated at different absorption edges; in the case of the n = 2 shell the bands below the threshold are extremely weak and most of the absorption intensity is due to excitations in the continuum. PMID:25754872

  6. Regulation of neuronal chloride homeostasis by neuromodulators.

    Science.gov (United States)

    Mahadevan, Vivek; Woodin, Melanie A

    2016-05-15

    KCC2 is the central regulator of neuronal Cl(-) homeostasis, and is critical for enabling strong hyperpolarizing synaptic inhibition in the mature brain. KCC2 hypofunction results in decreased inhibition and increased network hyperexcitability that underlies numerous disease states including epilepsy, neuropathic pain and neuropsychiatric disorders. The current holy grail of KCC2 biology is to identify how we can rescue KCC2 hypofunction in order to restore physiological levels of synaptic inhibition and neuronal network activity. It is becoming increasingly clear that diverse cellular signals regulate KCC2 surface expression and function including neurotransmitters and neuromodulators. In the present review we explore the existing evidence that G-protein-coupled receptor (GPCR) signalling can regulate KCC2 activity in numerous regions of the nervous system including the hypothalamus, hippocampus and spinal cord. We present key evidence from the literature suggesting that GPCR signalling is a conserved mechanism for regulating chloride homeostasis. This evidence includes: (1) the activation of group 1 metabotropic glutamate receptors and metabotropic Zn(2+) receptors strengthens GABAergic inhibition in CA3 pyramidal neurons through a regulation of KCC2; (2) activation of the 5-hydroxytryptamine type 2A serotonin receptors upregulates KCC2 cell surface expression and function, restores endogenous inhibition in motoneurons, and reduces spasticity in rats; and (3) activation of A3A-type adenosine receptors rescues KCC2 dysfunction and reverses allodynia in a model of neuropathic pain. We propose that GPCR-signals are novel endogenous Cl(-) extrusion enhancers that may regulate KCC2 function. PMID:26876607

  7. Design of zirconium tetra chloride purification apparatus

    International Nuclear Information System (INIS)

    Design of zirconium tetrachloride purification apparatus was done. The purification was done by sublimation and desublimation of zirconium tetrachloride compound. Zirconium tetrachloride,which was produced by the chlorination processes, was sublimated at 600oC then was desublimated at 331oC. The impurities could be separated. Zirconium tetra chloride was put at the tray in the column heated by the furnace, so that it sublimated. Ferri and Chromi salt was reduced to be ferro and chromo which could not be sublimated. Desublimation, was done in the cooler from pipe which was flowed by water. Cooler mode from 6 pieces of pipe, 1/4 inch in diameter and 30 cm in length. The water flow was 2.8 l/minute. Air was entered in the annulus surrounding the column. From the 80 cm length of the column, 50 cm was used for sublimation, and 30 cm for desublimation. Heat requirement was supplied by a furnace outside of the column. Heat flux could be arranged by the controller. (author)

  8. Redetermination of 1-carboxycyclohexan-1-aminium chloride

    Directory of Open Access Journals (Sweden)

    Teresa González

    2009-02-01

    Full Text Available The crystal structure of the title compound, C7H14NO2+·Cl−, was reported previously [Chacko, Srinivasan & Zand (1975. J. Cryst. Mol. Struct. 5, 353–357] from Weissenberg photographic data with R = 0.113. It has now been redetermined, providing a significant increase in the precision of the derived geometric parameters, viz. mean σ(C—C = 0.003 Å in the present work compared with 0.021 Å for the previous work. The complete cation is generated by crystallographic mirrror symmetry, with three C atoms, two O atoms and the N atom lying on the reflecting plane; the chloride anion also has m site symmetry. The crystal structure is established by a two-dimensional network of O—H...Cl and N—H...Cl hydrogen bonds, generating C12(4 and C12(7 chains, and R24(8 and R24(14 rings.

  9. NQR in tert-butyl chloride

    Science.gov (United States)

    Brunetti, Aldo H.

    2004-03-01

    Tert-butyl chloride has been broadly studied experimentally through various techniques such as X-ray crystallography, DTA, and NMR. It was also studied experimentally through nuclear quadrupole resonance (NQR), but this study was limited and incomplete. In this paper, we present a more detailed study of TBC through the NQR of 35Cl. Our results show that near 120 K, the onset of the CH 3 groups semirotations around symmetry axis C3 takes place with an activation energy U=16.1 kJ mol -1. This intramolecular movement produces a T1 minimum near 148 K and is the dominant mechanism of the nuclear spin-lattice relaxation in phase III of this compound. In phase II of TBC, we show that there are not only methyl groups semirotations, but also semirotations of the whole molecule around a different axis from the symmetry axis C' 3 (C-Cl bond) with an activation energy of E=10.4 kJ mol -1.

  10. Formation of plutonium phosphates in chloride melts

    Energy Technology Data Exchange (ETDEWEB)

    Burnaeva, A.A.; Kryukova, A.I.; Kazanstev, G' N.; Skiba, O.V.; Korshunov, I.A.

    1984-01-01

    Introduction of sodium- and potassium phosphates Na/sub 3/PO/sub 4/ and K/sub 3/PO/sub 4/ in the PuCl/sub 3/-NaCl, PuCl/sub 3/-KCl melts results in reduction of plutonium amount in the liquid phase. Low-soluble plutonium (3) phosphates, of assumed Na/sub 3/Pu/sub 2/ composition (PO/sub 4/)/sub 3/ are transported into the solid phase. Using the methods of radiographical and radiometric analyses the phases of plutonium phosphates separated by precipitation from chloride melt and also prepared from PuO/sub 2/ and NaH/sub 2/PO/sub 4/ at 1200 deg C are investigated. Their solubility in the NaCl-KCl melt and stability to these melts during a long-term contact, and also under the effect of CCl/sub 4/ are evaluated. The data are compared with similar data for thorium-, uranium-, americium-, curium-, zirconium-, rare earth phosphates.

  11. Durability Analysis of Subway Station in Chloride Environment

    Directory of Open Access Journals (Sweden)

    Yang LuFeng

    2013-02-01

    Full Text Available In this study, a finite element model for chloride ions transport in saturated concrete was proposed based on the Fick’s second law of diffusion. The governing partial differential equation was solved numerically in space as a boundary-value problem and in time as an initial-value problem by means of the finite element formulations. The maximum allowable value of chloride diffusion coefficient within different locations of subway station with service life of 100a was achieved and suggestions for durability analysis of subway station in chloride environment were also proposed.

  12. Stochastic Modeling of Reinforced Concrete Structures Exposed to Chloride Attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2003-01-01

    For many reinforced concrete structures corrosion of reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation is that the chloride content around...... the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface...

  13. Stochastic modeling of reinforced concrete structures exposed to chloride attack

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frier, Christian

    2004-01-01

    For many reinforced concrete structures corrosion of reinforcement is an important problem since it can result in expensive maintenance and repair actions. Further, a significant reduction of the load-bearing capacity can occur. One mode of corrosion initiation is that the chloride content around...... the reinforcement exceeds a critical threshold value. In the present paper a stochastic model is described by which the chloride content in a reinforced concrete structure can be estimated. The chloride ingress is modeled by a 2-dimensional diffusion process and the diffusion coefficient, surface...

  14. Molten Triazolium Chloride Systems as New Aluminum Battery Electrolytes

    DEFF Research Database (Denmark)

    Vestergaard, B.; Bjerrum, Niels; Petrushina, Irina;

    1993-01-01

    The possibility of using molten mixtures of 1,4-dimethyl-1,2,4-triazolium chloride (DMTC) and aluminum chloride (AlCl3) as secondary battery electrolytes was studied, in some cases extended by the copresence of sodium chloride. DMTC-AlCl, mixtures demonstrated high specific conductivity in a wide...... of milliamperes per square centimeter) was observed at 0.344 V on the acidic sodium tetrachloroaluminate background, involving a free triazolium radical mechanism. Molten DMTC-AlCl3 electrolytes are acceptable for battery performance and both the aluminum anode and the triazolium electrolyte can be...

  15. Denitrification of fertilizer wastewater at high chloride concentration

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Henze, Mogens

    Wastewater from fertilizer industry is characterized by high contents of chloride concentration, which normally vary between 60 and 76 g/l. Experiments with bilogical denitrification were performed in lab-scale "fill and draw" reactors with synthetic wastewater with chloride concentrations up to 77.......4 g/l. The results of the experiments showed that biological denitrification was feasible at the extreme environmental conditions prevailing in fertilizer wastewater. Stable continuous biological denitrfication of the synthetic high chloride wastewater was performed up to 77.4 g Cl/l at 37 degree C...

  16. Optimal control of batch emulsion polymerization of vinyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Damslora, Andre Johan

    1998-12-31

    The highly exothermic polymerization of vinyl chloride (VC) is carried out in large vessels where the heat removal represents a major limitation of the production rate. Many emulsion polymerization reactors are operated in such a way that a substantial part of the heat transfer capacity is left unused for a significant part of the total batch time. To increase the reaction rate so that it matches the heat removal capacity during the course of the reaction, this thesis proposes the use of a sufficiently flexible initiator system to obtain a reaction rate which is high throughout the reaction and real-time optimization to compute the addition policy for the initiator. This optimization based approach provides a basis for an interplay between design and control and between production and research. A simple model is developed for predicting the polymerization rate. The model is highly nonlinear and open-loop unstable and may serve as an interesting case for comparison of nonlinear control strategies. The model is fitted to data obtained in a laboratory scale reactor. Finally, the thesis discusses optimal control of the emulsion polymerization reactor. Reduction of the batch cycle time is of major economic importance, as long as the quality parameters are within their specifications. The control parameterization had a major influence on the performance. A differentiable spline parameterization was applied and the optimization is illustrated in a number of cases. The best performance is obtained when the reactor temperature is obtained when the optimization is combined with some form of closed-loop control of the reactor temperature. 112 refs., 48 figs., 4 tabs.

  17. 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.

  18. 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.

  19. 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.

  20. The earliest ion channels in protocellular membranes

    Science.gov (United States)

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

    indicates that their structures are unique and stable. In addition, it is also believed that the trichotoxin channel displays some selectivity between potassium and chloride ions. This makes trichotoxin and antiamoebin ideal models of the earliest ion channels that could provide insight into the origins of ion conductance and selectivity. In the absence of crystal structure of the trichotoxin and antiamoebin channels, we propose their molecular models based on experimentally determined number of monomers forming the bundles. We use molecular dynamics simulations to validate the models in terms of their conductance and selectivity. On the basis of our simulations we show that the emergence of channels built of small, α-helical peptides was protobiologically plausible and did not require highly specific amino acid sequences, which is a convenient evolutionary trait. Despite their simple structure, such channels could possess properties that, at the first sight, appear to require markedly larger complexity. To this end, we will discuss how the amino acid sequence and structure of primitive channels give rise to the phenomena of ionic conductance and selectivity across the earliest cell walls, which were essential functions for the emergence and early evolution of protocells. Furthermore, we will argue that even though architectures of membrane proteins are not nearly as diverse as those of water-soluble proteins, they are sufficiently flexible to adapt readily to the functional demands arising during evolution.

  1. Close to the Sky

    Science.gov (United States)

    2007-11-01

    Today, a new ALMA outreach and educational book was publicly presented to city officials of San Pedro de Atacama in Chile, as part of the celebrations of the anniversary of the Andean village. ESO PR Photo 50a/07 ESO PR Photo 50a/07 A Useful Tool for Schools Entitled "Close to the sky: Biological heritage in the ALMA area", and edited in English and Spanish by ESO in Chile, the book collects unique on-site observations of the flora and fauna of the ALMA region performed by experts commissioned to investigate it and to provide key initiatives to protect it. "I thank the ALMA project for providing us a book that will surely be a good support for the education of children and youngsters of San Pedro de Atacama. Thanks to this publication, we expect our rich flora and fauna to be better known. I invite teachers and students to take advantage of this educational resource, which will be available in our schools", commented Ms. Sandra Berna, the Mayor of San Pedro de Atacama, who was given the book by representatives of the ALMA global collaboration project. Copies of the book 'Close to the sky' will be donated to all schools in the area, as a contribution to the education of students and young people in northern Chile. "From the very beginning of the project, ALMA construction has had a firm commitment to environment and local culture, protecting unique flora and fauna species and preserving old estancias belonging to the Likan Antai culture," said Jacques Lassalle, who represented ALMA at the hand-over. "Animals like the llama, the fox or the condor do not only live in the region where ALMA is now being built, but they are also key elements of the ancient Andean constellations. In this sense they are part of the same sky that will be explored by ALMA in the near future." ESO PR Photo 50c/07 ESO PR Photo 50c/07 Presentation of the ALMA book The ALMA Project is a giant, international observatory currently under construction on the high-altitude Chajnantor site in Chile

  2. Applicability of boron-doped diamond electrode to the degradation of chloride-mediated and chloride-free wastewaters

    International Nuclear Information System (INIS)

    The electrochemical degradation of chloride-mediated and chloride-free dye wastewaters was investigated on a boron-doped diamond (BDD) electrode in comparison with that on a dimensionally stable anode (DSA), and the applicability of BDD electrode to the degradation of these two kinds of wastewaters was explored. In chloride-free wastewater, the electrochemical degradation efficiency of dye on BDD electrode was much higher than that on DSA, with a chemical oxygen demand (COD) removal of 100% and 26% for BDD and DSA, respectively. In chloride-mediated dye wastewater, COD removal was faster than that in chloride-free wastewater on both BDD and DSA electrodes with COD removal efficiencies higher than 95%, whereas the rate of COD removal on DSA was faster than that on BDD electrode. The investigation indicates that DSA is more suitable than BDD electrode in degradation of originally chloride contained dye wastewaters for the sake of energy and time saving. However, for chloride-free dye wastewaters, with the aim of environmental protection, BDD electrode is more appropriate to realize complete mineralization. At the same time, the secondary pollution can be avoided

  3. 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...

  4. 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)

  5. 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...

  6. 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.

  7. Adsorption of Tetradecylpyridinium Chloride on Aqueous Surfaces of Sodium Chloride Solutions

    OpenAIRE

    Fujio, Katsuhiko; Hayashi, Koji; Suzuki, Maki

    2014-01-01

    Surface tension of aqueous NaCl solutions of tetradecylpyridinium chloride (TPC) has been measured by the drop weight method at different NaCl concentrations from 0 to 1.000 mol dm−3 at 25◦C. Surface excess densities of tetradecylpyridinium ion (TP+), Cl− and Na+ have been obtained as functions of TPC concentration at different NaCl concentrations by applying the Gibbs adsorption isotherm to the surface tension data below the critical micelle concentration (CMC) of TPC. Surface excess densiti...

  8. Adsorption of Dodecylpyridinium Chloride on Aqueous Surfaces of Sodium Chloride Solutions

    OpenAIRE

    Fujio, Katsuhiko; TAKEUCHI, Kumiko; Suzuki, Maki

    2012-01-01

    Surface tension of aqueous NaCl solutions of dodecylpyridinium chloride (DPC) has been measured by the drop weight method at different NaCl concentrations from 0 to 1.000 mol dm-3 at 25℃. Applying the Gibbs adsorption isotherm to the surface tension data at DPC concentrations below the critical micelle concentration (CMC), surface excess densities of dodecylpyridinium ion (DP+), Cl- and Na+ have been obtained as functions of DPC concentration at different NaCl concentrations. Surface excess d...

  9. Effective capacity of correlated MISO channels

    KAUST Repository

    Zhong, Caijun

    2011-06-01

    This paper presents an analytical performance investigation of the capacity limits of correlated multiple-input single-output (MISO) channels in the presence of quality-of-service (QoS) requirements. Exact closed-form expression for the effective capacity of correlated MISO channels is derived. In addition, simple expressions are obtained at the asymptotic high and low signal-to-noise ratio (SNR) regimes, which provide insights into the impact of various system parameters on the effective capacity of the system. Also, a complete characterization of the impact of spatial correlation on the effective capacity is provided with the aid of a majorization theory result. The findings suggest that antenna correlation reduce the effective capacity of the channels. Moreover, a stringent QoS requirement causes a significant reduction in the effective capacity but this can be effectively alleviated by increasing the number of antennas. © 2011 IEEE.

  10. Nickel Chloride Promoted Glaser Coupling Reaction in Hot Water

    Institute of Scientific and Technical Information of China (English)

    Pin Hua LI; Lei WANG; Min WANG; Jin Can YAN

    2004-01-01

    A Glaser coupling reaction of terminal alkynes in the presence of nickel chloride without any organics and bases in hot water has been developed, which produces the corresponding homo-coupling products in good yields.

  11. Chloride supporting electrolytes for all-vanadium redox flow batteries.

    Science.gov (United States)

    Kim, Soowhan; Vijayakumar, M; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Chen, Feng; Hu, Jianzhi; Li, Liyu; Yang, Zhenguo

    2011-10-28

    This paper examines vanadium chloride solutions as electrolytes for an all-vanadium redox flow battery. The chloride solutions were capable of dissolving more than 2.3 M vanadium at varied valence states and remained stable at 0-50 °C. The improved stability appeared due to the formation of a vanadium dinuclear [V(2)O(3)·4H(2)O](4+) or a dinuclear-chloro complex [V(2)O(3)Cl·3H(2)O](3+) in the solutions over a wide temperature range. The all-vanadium redox flow batteries with the chloride electrolytes demonstrated excellent reversibility and fairly high efficiencies. Only negligible, if any, gas evolution was observed. The improved energy capacity and good performance, along with the ease in heat management, would lead to substantial reduction in capital cost and life-cycle cost, making the vanadium chloride redox flow battery a promising candidate for stationary applications. PMID:21922094

  12. Catalytic Decomposition of Methylene Chloride by Sulfated Titania Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Catalytic decomposition of methylene chloride in air below 300℃ was studied.Sulfated titania was very effective in converting 959ppm methylene chloride selectively to CO,CO2 and HCl.Complete decomposition of methylene chloride was achieved at low temperature(275℃).It was found that the acidic property of catalyst was a determinant factor for the catalytic activity.The presence of water vapor in the feed stream remarkably reduced the catalytic activity,which could be due to the blockage of acidic sites on the surface of catalyst by water molecules.A bifunctional catalyst comprising copper oxide was developed to improve the selectivity of catalytic oxidation,which indicated that copper oxide can promote the deep oxidation of methylene chloride.The crystal form of TiO2 imposes an important influence upon the catalytic oxidation.

  13. Thermodynamic calculation of self-diffusion in sodium chloride

    Science.gov (United States)

    Zhang, Baohua; Li, Chengbo; Shan, Shuangming

    2016-05-01

    Using the available pressure-volume-temperature equation of state of sodium chloride, we show that the self-diffusion coefficients of sodium and chloride in sodium chloride as a function of temperature and pressure can be successfully reproduced in terms of bulk elastic and expansivity data. We use a thermodynamic model that interconnects point-defect parameters with bulk properties. Our calculated diffusion coefficients and point-defect parameters, including activation enthalpy, activation entropy, and activation volume, well agree with reported experimental results when uncertainties are considered. Furthermore, the ionic conductivity of sodium chloride inferred from our predicted diffusivities of sodium through the Nernst-Einstein equation is compared with previous experimental data.

  14. Laboratory stress corrosion cracking studies with sulfur acids and chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Baylor, V.B.

    1985-10-01

    Stress corrosion cracking (SCC) caused by polythionic acid and/or chlorides has occurred in coal liquefaction pilot plants. This problem is also common in refineries and has been extensively researched. This study examines: (1) the relationship of the ASTM standard ferric sulfate-sulfuric acid test for determining sensitization to resistance to polythionic SCC; (2) the cracking resistance of higher-alloy. Fe-Ni-Cr materials and common austenitic stainless steels (SS); and (3) the effect of chloride concentrations up to 1% in polythionic acid solutions on cracking behavior. The ferric sulfatesulfuric acid test can be used as an acceptance test for materials resistant to polythionic acid SCC. More highly alloyed materials were more resistant to sensitization than most austenitic SS and were virtually unattacked in polythionic acid solutions containing up to 1% chloride. Chloride increased the corrosion rate and caused localized pitting but it did not significantly affect the number of failures or the failure mode.

  15. Use of saturated sodium chloride solution as a tissue fixative

    Directory of Open Access Journals (Sweden)

    A. Al-Saraj

    2010-01-01

    Full Text Available The present study was carried out to examine the capability of saturated sodium chloride solution as a fixative agent instead of formalin which is regarded as a carcinogenic material. For this purpose 3 rabbits were used and their livers, kidneys and spleens were exposed and removed. Neutral buffered formalin solution, saturated sodium chloride solution and distilled water were used as fixatives for specimens obtained from the first, second and third rabbits respectively. Routine histological technique was performed to prepare a stained histological sections for light microscopic examination. The result showed that the tissue sections which were obtained by using sodium chloride have the same histological features and without any artifacts when they compared with the results obtained using formalin fixation method. We conclude that the saturated sodium chloride solution can be used as a fixative agent in some circumstances when no any fixative agent is available.

  16. Solidification of spent TBP solvent with aluminium chloride compounds

    International Nuclear Information System (INIS)

    The new techniques for processing spent TBP was investigated. It was proved that treatment of TBP containing DBP with aluminium chloride resulted in the formation of aluminium phosphate suitable for long term storage and final disposal

  17. Methyltrioctylammonium chloride catalysed sonochemical synthesis of acridine diones

    Indian Academy of Sciences (India)

    Bhupinder Kaur; Harish Kumar

    2013-09-01

    The greener, clean and efficient protocol for the synthesis of acridine diones derivatives has been achieved by reacting aromatic aldehyde, dimedone and amines using methyltrioctylammonium chloride (Aliquate 336) as a catalyst under ultrasonic irradiations.

  18. Mechanisms of chloride decomposition in upgrading oil sands bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Le, T.; Diaz, D.; Gray, M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Eaton, P. [Champion Technologies, Fresno, TX (United States); Wu, A. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2004-07-01

    In addition to clay minerals, bitumens from mining operations contain chloride salts because of the salinity of the extraction process water and the connate water in the ore. These chlorides form corrosive hydrochloric acid. High concentrations of organic acid components known as naphthenic acids are also found in bitumen from Alberta's oil sands. These also cause corrosion. Chloride salts, clays and organic acids may interact in the presence of steam to promote hydrochloric acid formation causing major corrosion problems in downstream facilities. This study examined the behaviour of these components under upgrading conditions. In particular, it examined the rate and the extent of the hydrolysis reactions for salts found in bitumen. Mixtures of bitumen, salts and organic acids were exposed to flowing steam at 100 to 400 degrees C under nitrogen purge. Ion chromatography was used to analyze the condensed vapours for chloride.

  19. Reinforcement corrosion in alkaline chloride media with reduced oxygen concentrations

    International Nuclear Information System (INIS)

    It is commonly considered that the corrosion of steel in concrete is controlled by the oxygen content of the pore solution and there are service life models that relate the corrosion rate to the amount of oxygen. It is also commonly believed that in water saturated conditions the oxygen content in the pores is negligible and that underwater there is no risk of depassivation and the corrosion rate is very low. However, the available data on corrosion rates in immersed conditions do not indicate such performance; on the contrary corrosion develops when sufficient chloride reaches the reinforcement. In the present paper, results are presented for tests performed in alkaline chloride solutions that were purged with nitrogen to reduce the oxygen content. The results indicate that at very low oxygen concentrations, corrosion may develop in the presence of chlorides. The presence or absence of corrosion is influenced by the amount of chloride, the corrosion potential and the steel surface condition. (authors)

  20. Micellar solubilization in strongly interacting binary surfactant systems. [Binary surfactant systems of: dodecyltrimethylammonium chloride + sodium dodecyl sulfate; benzyldimethyltetradecylammonium chloride + tetradecyltrimethylammonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))

    1990-07-01

    The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.