Na+ -K+ -2Cl- Cotransporter (NKCC) Physiological Function in Nonpolarized Cells and Transporting Epithelia.

Science.gov (United States)

Delpire, Eric; Gagnon, Kenneth B

2018-03-25

Two genes encode the Na + -K + -2Cl - cotransporters, NKCC1 and NKCC2, that mediate the tightly coupled movement of 1Na + , 1K + , and 2Cl - across the plasma membrane of cells. Na + -K + -2Cl - cotransport is driven by the chemical gradient of the three ionic species across the membrane, two of them maintained by the action of the Na + /K + pump. In many cells, NKCC1 accumulates Cl - above its electrochemical potential equilibrium, thereby facilitating Cl - channel-mediated membrane depolarization. In smooth muscle cells, this depolarization facilitates the opening of voltage-sensitive Ca 2+ channels, leading to Ca 2+ influx, and cell contraction. In immature neurons, the depolarization due to a GABA-mediated Cl - conductance produces an excitatory rather than inhibitory response. In many cell types that have lost water, NKCC is activated to help the cells recover their volume. This is specially the case if the cells have also lost Cl - . In combination with the Na + /K + pump, the NKCC's move ions across various specialized epithelia. NKCC1 is involved in Cl - -driven fluid secretion in many exocrine glands, such as sweat, lacrimal, salivary, stomach, pancreas, and intestine. NKCC1 is also involved in K + -driven fluid secretion in inner ear, and possibly in Na + -driven fluid secretion in choroid plexus. In the thick ascending limb of Henle, NKCC2 activity in combination with the Na + /K + pump participates in reabsorbing 30% of the glomerular-filtered Na + . Overall, many critical physiological functions are maintained by the activity of the two Na + -K + -2Cl - cotransporters. In this overview article, we focus on the functional roles of the cotransporters in nonpolarized cells and in epithelia. © 2018 American Physiological Society. Compr Physiol 8:871-901, 2018. Copyright © 2018 American Physiological Society. All rights reserved.

Vasopressin alters the mechanism of apical Cl- entry from Na+:Cl- to Na+:K+:2Cl- cotransport in mouse medullary thick ascending limb

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Sun, A.; Grossman, E.B.; Lombardi, M.; Hebert, S.C. (Brigham and Women' s Hospital, Boston, MA (USA))

1991-02-01

Experiments were performed using in vitro perfused medullary thick ascending limbs of Henle (MTAL) and in suspensions of MTAL tubules isolated from mouse kidney to evaluate the effects of arginine vasopressin (AVP) on the K+ dependence of the apical, furosemide-sensitive Na{sup +}:Cl{sup {minus}} cotransporter and on transport-related oxygen consumption (QO{sub 2}). In isolated perfused MTAL segments, the rate of cell swelling induced by removing K+ from, and adding one mM ouabain to, the basolateral solution (ouabain(zero-K+)) provided an index to apical cotransporter activity and was used to evaluate the ionic requirements of the apical cotransporter in the presence and absence of AVP. In the absence of AVP cotransporter activity required Na{sup +} and Cl{sup {minus}}, but not K{sup +}, while the presence of AVP the apical cotransporter required all three ions. {sup 86}Rb{sup +} uptake into MTAL tubules in suspension was significant only after exposure of tubules to AVP. Moreover, {sup 22}Na{sup +} uptake was unaffected by extracellular K+ in the absence of AVP while after AVP exposure {sup 22}Na{sup +} uptake was strictly K{sup +}-dependent. The AVP-induced coupling of K{sup +} to the Na{sup +}:Cl{sup {minus}} cotransporter resulted in a doubling in the rate of NaCl absorption without a parallel increase in the rate of cellular {sup 22}Na{sup +} uptake or transport-related oxygen consumption. These results indicate that arginine vasopressin alters the mode of a loop diuretic-sensitive transporter from Na{sup +}:Cl{sup {minus}} cotransport to Na{sup +}:K{sup +}:2Cl{sup {minus}} cotransport in the mouse MTAL with the latter providing a distinct metabolic advantage for sodium transport. A model for AVP action on NaCl absorption by the MTAL is presented and the physiological significance of the coupling of K{sup +} to the apical Na{sup +}:Cl{sup {minus}} cotransporter in the MTAL and of the enhanced metabolic efficiency are discussed.

Mild KCC2 hypofunction causes inconspicuous chloride dysregulation that degrades neural coding

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Nicolas eDoyon

2016-01-01

Full Text Available Disinhibition caused by Cl- dysregulation is implicated in several neurological disorders. This form of disinhibition, which stems primarily from impaired Cl- extrusion through the co-transporter KCC2, is typically identified by a depolarizing shift in GABA reversal potential (EGABA. Here we show, using computer simulations, that intracellular [Cl-] exhibits exaggerated fluctuations during transient Cl- loads and recovers more slowly to baseline when KCC2 level is even modestly reduced. Using information theory and signal detection theory, we show that increased Cl- lability and settling time degrade neural coding. Importantly, these deleterious effects manifest after less KCC2 reduction than needed to produce the gross changes in EGABA required for detection by most experiments, which assess KCC2 function under weak Cl- load conditions. By demonstrating the existence and functional consequences of occult Cl- dysregulation, these results suggest that modest KCC2 hypofunction plays a greater role in neurological disorders than previously believed.

Cotransport of water by the Na+-K+-2Cl(-) cotransporter NKCC1 in mammalian epithelial cells

DEFF Research Database (Denmark)

Hamann, Steffen; Herrera-Perez, José J; Zeuthen, Thomas

2010-01-01

Water transport by the Na+-K+-2Cl(-) cotransporter (NKCC1) was studied in confluent cultures of pigmented epithelial (PE) cells from the ciliary body of the fetal human eye. Interdependence among water, Na+ and Cl(-) fluxes mediated by NKCC1 was inferred from changes in cell water volume, monitored...

Modeling glial contributions to seizures and epileptogenesis: cation-chloride cotransporters in Drosophila melanogaster.

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Zeid M Rusan

Full Text Available Flies carrying a kcc loss-of-function mutation are more seizure-susceptible than wild-type flies. The kcc gene is the highly conserved Drosophila melanogaster ortholog of K+/Cl- cotransporter genes thought to be expressed in all animal cell types. Here, we examined the spatial and temporal requirements for kcc loss-of-function to modify seizure-susceptibility in flies. Targeted RNA interference (RNAi of kcc in various sets of neurons was sufficient to induce severe seizure-sensitivity. Interestingly, kcc RNAi in glia was particularly effective in causing seizure-sensitivity. Knockdown of kcc in glia or neurons during development caused a reduction in seizure induction threshold, cell swelling, and brain volume increase in 24-48 hour old adult flies. Third instar larval peripheral nerves were enlarged when kcc RNAi was expressed in neurons or glia. Results suggest that a threshold of K+/Cl- cotransport dysfunction in the nervous system during development is an important determinant of seizure-susceptibility in Drosophila. The findings presented are the first attributing a causative role for glial cation-chloride cotransporters in seizures and epileptogenesis. The importance of elucidating glial cell contributions to seizure disorders and the utility of Drosophila models is discussed.

PDGF activates K-Cl cotransport through phosphoinositide 3-kinase and protein phosphatase-1 in primary cultures of vascular smooth muscle cells.

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Zhang, Jing; Lauf, Peter K; Adragna, Norma C

2005-07-15

K-Cl cotransport (K-Cl COT, KCC) is an electroneutrally coupled movement of K and Cl present in most cells. In this work, we studied the pathways of regulation of K-Cl COT by platelet-derived growth factor (PDGF) in primary cultures of vascular smooth muscle cells (VSMCs). Wortmannin and LY 294002 blocked the PDGF-induced K-Cl COT activation, indicating that the phosphoinositide 3-kinase (PI 3-K) pathway is involved. However, PD 98059 had no effect on K-Cl COT activation by PDGF, suggesting that the mitogen-activated protein kinase pathway is not involved under the experimental conditions tested. Involvement of phosphatases was also examined. Sodium orthovanadate, cyclosporin A and okadaic acid had no effect on PDGF-stimulated K-Cl COT. Calyculin A blocked the PDGF-stimulated K-Cl COT by 60%, suggesting that protein phosphatase-1 (PP-1) is a mediator in the PDGF signaling pathway/s. In conclusion, our results indicate that the PDGF-mediated pathways of K-Cl COT regulation involve the signaling molecules PI 3-K and PP-1.

Enhanced synaptic activity and epileptiform events in the embryonic Kcc2 deficient hippocampus

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Ilgam eKhalilov

2011-11-01

Full Text Available The neuronal potassium-chloride co-transporter Kcc2 is thought to play an important role in the post natal excitatory to inhibitory switch of GABA actions in the rodent hippocampus. Here, by studying hippocampi of wild-type (Kcc2+/+ and Kcc2 deficient (Kcc2-/- mouse embryos, we unexpectedly found increased spontaneous neuronal network activity at E18.5, a developmental stage when Kcc2 is thought not to be functional in the hippocampus. Embryonic Kcc2-/- hippocampi have also an augmented synapse density and a higher frequency of spontaneous glutamatergic and GABAergic postsynaptic currents (PSCs than naïve age matched neurons. However, intracellular chloride concentration ([Cl-]i and the reversal potential of GABA-mediated currents (EGABA were similar in embryonic Kcc2+/+ and Kcc2-/- CA3 neurons. In addition, Kcc2 immuno-labelling was cytoplasmic in the majority of neurons suggesting that the molecule is not functional as a plasma membrane chloride co-transporter. Collectively, our results show that already at an embryonic stage, Kcc2 controls the formation of synapses and, when deleted, the hippocampus has a higher density of GABAergic and glutamatergic synapses and generates spontaneous and evoked epileptiform activities. These results may be explained either by a small population of orchestrating neurons in which Kcc2 operates early as a chloride exporter or by transporter independent actions of Kcc2 that are instrumental in synapses formation and networks construction.

Effect of co-transporter blockers on non-synaptic epileptiform activity—computational simulation

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Rodrigues Lopes, Mariana; Canton Santos, Luiz Eduardo; Márcio Rodrigues, Antônio; Antônio Duarte, Mario; Catelli Infantosi, Antonio Fernando; Alexandre Scorza, Fulvio; Arida, Ricardo Mario; Madureira, Ana Paula; Amaral da Silveira, Gilcélio; dos Santos, Ivans Carlos; Abrão Cavalheiro, Esper; Guimarães de Almeida, Antônio-Carlos

2013-10-01

The important role of cation-chloride co-transporters in epilepsy is being supported by an increasing number of investigations. However, enormous complexity is involved since the action of these co-transporters has effects on the ionic homeostasis influencing directly the neuronal excitability and the tissue propensity to sustain seizure. To unravel the complex mechanisms involving the co-transporters action during seizure, this paper shows simulations of non-synaptic epileptiform activity and the effect of the blockage of the two different types of cation-chloride co-transporters present in the brain: Na, K and 2Cl co-transporter (NKCC) and K and Cl co-transporter (KCC). The simulations were performed with an electrochemical model representing the non-synaptic structure of the granule cell layer of the dentate gyrus (DG) of the rat hippocampus. The simulations suggest: (i) the potassium clearance is based on the systemic interplay between the Na/K pump and the NKCC co-transporters; (ii) the simultaneous blockage of the NKCC of the neurons and KCC of glial cells acts efficiently suppressing the epileptiform activities; and (iii) the simulations show that depending on the combined blockage of the co-transporters, the epileptiform activities may be suppressed or enhanced.

Tyrosine transport in winter flounder intestine: Interaction with Na+-K+-2Cl- cotransport

International Nuclear Information System (INIS)

Musch, M.W.; McConnell, F.M.; Goldstein, L.; Field, M.

1987-01-01

Tyrosine absorption across the brush border of the intestinal epithelium of the winter flounder Pseudopleuronectes americanus was studied in Ussing chambers modified to determine early rates of uptake. At 0.1 mM tyrosine, the 4-min rate of uptake (influx) of tyrosine across the brush border averaged 37.5 nmol·cm -2 ·h -1 . Omission of Na decreased influx by 60%, indicting that tyrosine influx occurs, at least in part, by a Na-coupled process. Ouabain inhibited influx by 80%. Inhibition of brush border Na + -K + -2Cl - cotransport by bumetanide, 8-bromo-cyclic GMP, or Cl replacement stimulated tyrosine influx 2.5- to 4-fold. However, atriopeptin III, which also inhibits Na + -K + -2Cl - cotransport, did not stimulate tyrosine influx. Cyclic AMP, which does not appear to inhibit ion cotransport, did not stimulate tyrosine influx. Both cyclic GMP and bumetanide also stimulated the net mucosa-to-serosa tyrosine flux (43 and 29%, respectively) and increased the cellular concentration of tyrosine by 50%. Thus tyrosine's influx is increased to a greater extent than is its transmural flux or its cellular concentration, suggesting that the main change occurs at the brush border and represents large increases in both influx and efflux of tyrosine across this membrane

Water permeability of Na+-K+-2Cl- cotransporters in mammalian epithelial cells

DEFF Research Database (Denmark)

Hamann, Steffen; Herrera-Perez, José Jaime; Bundgaard, Magnus

2005-01-01

Water transport properties of the Na+-K+-2Cl- cotransporter (NKCC) were studied in cultures of pigmented epithelial cells (PE) from the ciliary body of the eye. Here, the membrane that faces upwards contains NKCCs and can be subjected to rapid changes in bathing solution composition and osmolarity...

General anaesthetics do not impair developmental expression of the KCC2 potassium-chloride cotransporter in neonatal rats during the brain growth spurt

KAUST Repository

Lacoh, Claudia Marvine

2013-03-26

BackgroundThe developmental transition from depolarizing to hyperpolarizing γ-aminobutyric acid-mediated neurotransmission is primarily mediated by an increase in the amount of the potassium-chloride cotransporter KCC2 during early postnatal life. However, it is not known whether early neuronal activity plays a modulatory role in the expression of total KCC2 mRNA and protein in the immature brain. As general anaesthetics are powerful modulators of neuronal activity, the purpose of this study was to explore how these drugs affect KCC2 expression during the brain growth spurt.MethodsWistar rat pups were exposed to either a single dose or 6 h of midazolam, propofol, or ketamine anaesthesia at postnatal days 0, 5, 10, or 15. KCC2 expression was assessed using immunoblotting, immunohistochemistry, or quantitative polymerase chain reaction analysis up to 3 days post-exposure in the medial prefrontal cortex.ResultsThere was a progressive and steep increase in the expression of KCC2 between birth and 2 weeks of age. Exposure to midazolam, propofol, or ketamine up to 6 h at any investigated stages of the brain growth spurt did not influence the expression of this cotransporter protein.ConclusionI.V. general anaesthetics do not seem to influence developmental expression of KCC2 during the brain growth spurt. © 2013 © The Author [2013].

Contribution of the basolateral isoform of the Na-K-2Cl- cotransporter (NKCC1/BSC2) to renin secretion

DEFF Research Database (Denmark)

Castrop, Hayo; Lorenz, John N; Hansen, Pernille B

2005-01-01

Acute administration of loop diuretics like furosemide leads to a stimulation of renin secretion, an effect thought to result from inhibition of Na-K-2Cl cotransporter (NKCC2)-mediated salt transport at the luminal surface of the macula densa (MD). However, loop diuretics also inhibit NKCC1......, the second isoform of the Na-K-2Cl cotransporter, with similar potency. In the present study, we examined the influence of furosemide on renin secretion in NKCC1-deficient mice to distinguish between effects of the loop diuretic involving NKCC2 and, by implication, the MD pathway, and effects that might...

The effect of repeated stress on KCC2 and NKCC1 immunoreactivity in the hippocampus of female mice

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Takao Tsukahara

2016-03-01

Full Text Available K+–Cl− co-transporter (KCC2 and Na+–K+–2Cl− co-transporter (NKCC1 are the main regulators of neuronal intracellular chloride concentration; altered expression patterns of KCC2 and NKCC1 have been reported in several neurodegenerative diseases. In this paper, we show the effect of repeated stress on KCC2, NKCC1, and serine 940 phosphorylated KCC2 (pKCC2ser940 immunoreactivity.The data were obtained from the hippocampus of female mice using single-plane confocal microscopy images. The mean fluorescence intensity of the perisomatic area of neurons, defined as raw fluorescence intensity (RFI was calculated. Repeated stress (RS resulted in a decrease in perisomatic area of immunoreactive (IR-KCC2 and an increase of the IR-NKCC1. In addition, RS decreased perisomatic IR-pKCC2ser940, corresponding to that of KCC2. The data in this article support the results of a previous study [1] and provide the details of immunohistological methods. Interpretation of the data in this article can be found in “Repeated stress-induced expression pattern alterations of the hippocampal chloride transporters KCC2 and NKCC1 associated with behavioral abnormalities in female mice” by Tsukahara et al. [1]. Keywords: KCC2, NKCC1, repeated stress, IHC

A mathematical model of rat ascending Henle limb. I. Cotransporter function.

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Weinstein, Alan M

2010-03-01

Kinetic models of Na+-K+-2Cl- costransporter (NKCC2) and K+-Cl- cotransporter (KCC4), two of the key cotransporters of the Henle limb, are fashioned with inclusion of terms representing binding and transport of NH4+. The models are simplified using assumptions of equilibrium ion binding, binding symmetry, and identity of Cl- binding sites. Model parameters are selected to be consistent with flux data from expression of these transporters in oocytes, specifically inwardly directed coupled transport of rubidium. In the analysis of these models, it is found that despite the simplifying assumptions to reduce the number of model parameters, neither model is uniquely determined by the data. For NKCC or KCC there are two- or three-parameter families of "optimal" solutions. As a consequence, one may specify several carrier translocation rates and/or ion affinities before fitting the remaining coefficients to the data, with no loss of fidelity in simulating the experiments. Model calculations suggest that with respect to NKCC2 near its operating point, the curve of ion flux as a function of cell Cl- is steep, and with respect to KCC4, its curve of ion flux as a function of peritubular K+ is also steep. The implication is that the kinetics are suitable for these two transporters in series to act as a sensor for peritubular K+, to modulate AHL Na+ reabsorption, with cytosolic Cl- as the intermediate variable. The models also reveal the potential for luminal NH4+ to be a potent catalyst for NKCC2 Na+ reabsorption, provided suitable exit mechanisms for NH4+ (from cell-to-lumen) are operative. It is found that KCC4 is likely to augment the secretory NH4+ flux, with peritubular NH4+ uptake driven by the cell-to-blood K+ gradient.

Lithium fluxes indicate presence of Na-Cl cotransport (NCC) in human lens epithelial cells.

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Lauf, Peter K; Chimote, Ameet A; Adragna, Norma C

2008-01-01

During regulatory volume decrease (RVD) of human lens epithelial cells (hLECs) by clotrimazole (CTZ)-sensitive K fluxes, Na-K-2Cl cotransport (NKCC) remains active and K-Cl cotransport (KCC) inactive. To determine whether such an abnormal behavior was caused by RVD-induced cell shrinkage, NKCC was measured in the presence of either CTZ or in high K media to prevent RVD. NKCC transports RbCl + NaCl, and LiCl + KCl; thus ouabain-insensitive, bumetanide-sensitive (BS) or Cl-dependent (ClD) Rb and Li fluxes were determined in hyposmotic high NaCl media with CTZ, or in high KCl media alone, or with sulfamate (Sf) or nitrate as Cl replacement at varying Rb, Li or Cl mol fractions (MF). Unexpectedly, NKCC was inhibited by 80% with CTZ (IC(50) = 31 microM). In isosmotic (300 mOsM) K, Li influx was approximately 1/3 of Rb influx in Na, 50% lower in Sf, and bumetanide-insensitive (BI). In hypotonic (200 mOsM) K, only the ClD but not BS Li fluxes were detected. At Li MFs from 0.1-1, Li fluxes fitted a bell-shaped curve maxing at approximately 0.6 Li MF, with the BS fluxes equaling approximately 1/4 of the ClD-Li influx. The difference, i.e. the BI/ClD Li influx, saturated with increasing Li and Cl MFs, with K(ms) for Li of 11 with, and 7 mM without K, and of approximately 46 mM for Cl. Inhibition of this K-independent Li influx by thiazides was weak whilst furosemide (<100 microM) was ineffective. Reverse transcription polymerase chain reaction and Western blots verified presence of both NKCC1 and Na-Cl cotransport (NCC). In conclusion, in hyposmotic high K media, which prevents CTZ-sensitive K flux-mediated RVD in hLECs, NKCC1, though molecularly expressed, was functionally silent. However, a K-independent and moderately thiazide-sensitive ClD-Li flux, i.e. LiCC, likely occurring through NCC was detected operationally and molecularly. (c) 2008 S. Karger AG, Basel.

Vasoconstriction triggered by hydrogen sulfide: Evidence for Na+,K+,2Cl-cotransport and L-type Ca2+ channel-mediated pathway.

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Orlov, Sergei N; Gusakova, Svetlana V; Smaglii, Liudmila V; Koltsova, Svetlana V; Sidorenko, Svetalana V

2017-12-01

This study examined the dose-dependent actions of hydrogen sulfide donor sodium hydrosulphide (NaHS) on isometric contractions and ion transport in rat aorta smooth muscle cells (SMC). Isometric contraction was measured in ring aortas segments from male Wistar rats. Activity of Na + /K + -pump and Na + ,K + ,2Cl - cotransport was measured in cultured endothelial and smooth muscle cells from the rat aorta as ouabain-sensitive and ouabain-resistant, bumetanide-sensitive components of the 86 Rb influx, respectively. NaHS exhibited the bimodal action on contractions triggered by modest depolarization ([K + ] o =30 mM). At 10 -4 M, NaHS augmented contractions of intact and endothelium-denuded strips by ~ 15% and 25%, respectively, whereas at concentration of 10 -3  M it decreased contractile responses by more than two-fold. Contractions evoked by 10 -4  M NaHS were completely abolished by bumetanide, a potent inhibitor of Na + ,K + ,2Cl - cotransport, whereas the inhibition seen at 10 -3  M NaHS was suppressed in the presence of K + channel blocker TEA. In cultured SMC, 5×10 -5  M NaHS increased Na + ,K + ,2Cl - - cotransport without any effect on the activity of this carrier in endothelial cells. In depolarized SMC, 45 Ca influx was enhanced in the presence of 10 -4  M NaHS and suppressed under elevation of [NaHS] up to 10 -3  M. 45 Ca influx triggered by 10 -4  M NaHS was abolished by bumetanide and L-type Ca 2+ channel blocker nicardipine. Our results strongly suggest that contractions of rat aortic rings triggered by low doses of NaHS are mediated by activation of Na + ,K + ,2Cl - cotransport and Ca 2+ influx via L-type channels.

Characteristics and functions of Na-K-Cl cotransport in epithelial tissues

International Nuclear Information System (INIS)

O'Grady, S.M.; Palfrey, H.C.; Field, M.

1987-01-01

This review summarizes our present understanding of Na-K-Cl cotransport and its physiological role in absorption and secretion of electrolytes and water in epithelial tissues. In the past several years an extensive literature about this cotransporter has developed due to its widespread distribution in a variety of cell types and its essential role in fluid and electrolyte transport in several epithelial tissues. We summarize this literature and speculate on the future characterization of this transport system. Although this review focuses on cotransport as it relates to absorptive and secretory processes in epithelia, important information concerning the pharmacology, stoichiometry, and regulation of Na-K-Cl cotransport in nonepithelial systems (i.e., erythrocytes, fibroblasts, squid axon, etc.) has been included to supplement areas that are less well established in the epithelial literature. 114 references

KCC2-dependent Steady-state Intracellular Chloride Concentration and pH in Cortical Layer 2/3 Neurons of Anesthetized and Awake Mice.

Science.gov (United States)

Boffi, Juan C; Knabbe, Johannes; Kaiser, Michaela; Kuner, Thomas

2018-01-01

Neuronal intracellular Cl - concentration ([Cl - ] i ) influences a wide range of processes such as neuronal inhibition, membrane potential dynamics, intracellular pH (pH i ) or cell volume. Up to date, neuronal [Cl - ] i has predominantly been studied in model systems of reduced complexity. Here, we implemented the genetically encoded ratiometric Cl - indicator Superclomeleon (SCLM) to estimate the steady-state [Cl - ] i in cortical neurons from anesthetized and awake mice using 2-photon microscopy. Additionally, we implemented superecliptic pHluorin (SE-pHluorin) as a ratiometric sensor to estimate the intracellular steady-state pH (pH i ) of mouse cortical neurons in vivo . We estimated an average resting [Cl - ] i of 6 ± 2 mM with no evidence of subcellular gradients in the proximal somato-dendritic domain and an average somatic pH i of 7.1 ± 0.2. Neither [Cl - ] i nor pH i were affected by isoflurane anesthesia. We deleted the cation-Cl - co-transporter KCC2 in single identified neurons of adult mice and found an increase of [Cl - ] i to approximately 26 ± 8 mM, demonstrating that under in vivo conditions KCC2 produces low [Cl - ] i in adult mouse neurons. In summary, neurons of the brain of awake adult mice exhibit a low and evenly distributed [Cl - ] i in the proximal somato-dendritic compartment that is independent of anesthesia and requires KCC2 expression for its maintenance.

KCC isoforms in a human lens epithelial cell line (B3) and lens tissue extracts.

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Misri, Sandeep; Chimote, Ameet A; Adragna, Norma C; Warwar, Ronald; Brown, Thomas L; Lauf, Peter K

2006-11-01

We recently reported potassium-chloride cotransporter activity in human lens epithelial B3 (HLE-B3) cells. The purpose of the present study was to demonstrate in these cells as well as in human lens tissue the potassium-chloride cotransport (KCC) isoforms by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence microscopy. Of the four KCC genes known to encode the respective proteins and their spliced variants, RT-PCR with both rat and human primers revealed the predicted cDNA fragments of KCC1, KCC3a, KCC3b, and KCC4 but not KCC2 in both HLE-B3 cells and in human lens tissue extracts from cataractous patients. Polyclonal rabbit (rb) anti-rat (rt) and anti-human (hm) antibodies against rtKCC1 and hmKCC3, respectively, and a commercially available rb-anti-mouse (ms) KCC4 antibody were used. Rb anti-rtKCC1-ECL3 [against epitopes within the large extracellular loop 3 (ECL3)] revealed a 150kDa band in HLE-B3 cells consistent with the known molecular weight of KCC1. Rb anti-hmKCC3-ECL3 yielded three bands of 150, 122 and 105kDa, evidence for the presence of KCC3a, KCC3b and possibly KCC3c isoforms. The 122 and 112kDa bands were also demonstrated by rb anti-hmKCC3-CTD [the C-terminal domain (CTD)]. Rb anti-msKCC4 antibody only showed a 100kDa band in HLE-B3 cells. In the human lens tissues, a 115kDa protein was detected with rb anti-rtKCC1-ECL3 and a 100kDa band with rb anti-msKCC4, however, no bands with rb anti-hmKCC3-ECL3 or rb anti-hmKCC3-CTD. Fluorescence microscopy revealed immunocytochemical cytoplasmic and membrane labeling of HLE-B3 cells with anti-KCC1, -KCC3 (laser confocal microscopy) and -KCC4 antibodies and a Cy3-tagged secondary antibody. Hence HLE-B3 cells expressed proteins of the KCC1, KCC3a, b, and KCC4 isoforms, whereas surgically removed cataractous lens tissue expressed only those of KCC1 and KCC4.

Dynamics of Na+,K+,2Cl- cotransporter and Na+,K+-ATPase expression in the branchial epithelium of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar)

DEFF Research Database (Denmark)

Tipsmark, Christian Kølbæk; Madsen, Steffen; Seidelin, Michel

2002-01-01

The dynamics of branchial Na+,K+,2Cl- cotransporter (NKCC) and Na+,K+-ATPase (NKA) expression were investigated in brown trout and Atlantic salmon during salinity shifts and the parr-smolt transformation, respectively. In the brown trout, Western blotting revealed that NKCC and NKA abundance...

Reactive neurogenesis and down-regulation of the potassium-chloride cotransporter KCC2 in the cochlear nuclei after cochlear deafferentation

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Brahim Tighilet

2016-08-01

Full Text Available While many studies have been devoted to investigating the homeostatic plasticity triggered by cochlear hearing loss, the cellular and molecular mechanisms involved in these central changes remain elusive. In the present study, we investigated the possibility of reactive neurogenesis after unilateral cochlear nerve section in the cochlear nucleus of cats. We found a strong cell proliferation in all the cochlear nucleus sub-divisions ipsilateral to the lesion. Most of the newly generated cells survive up to one month after cochlear deafferentation in all cochlear nuclei (except the dorsal cochlear nucleus and give rise to a variety of cell types, i.e. microglial cells, astrocytes and neurons. Interestingly, many of the newborn neurons had an inhibitory (GABAergic phenotype. This result is intriguing since sensory deafferentation is usually accompanied by enhanced excitation, consistent with a reduction in central inhibition. The membrane potential effect of GABA depends, however, on the intra-cellular chloride concentration, which is maintained at low levels in adults by the potassium chloride co-transporter KCC2. The KCC2 density on the plasma membrane of neurons was then assessed after cochlear deafferentation in the cochlear nuclei ipsilateral and contralateral to the lesion. Cochlear deafferentation is accompanied by a strong down-regulation of KCC2 ipsilateral to the lesion at 3 and 30 days post-lesion. This study suggests that reactive neurogenesis and downregulation of KCC2 is part of the vast repertoire involved in homeostatic plasticity triggered by hearing loss. These central changes may also play a role in the generation of tinnitus and hyperacusis.

Apparent intermediate K conductance channel hyposmotic activation in human lens epithelial cells.

Science.gov (United States)

Lauf, Peter K; Misri, Sandeep; Chimote, Ameet A; Adragna, Norma C

2008-03-01

This study explores the nature of K fluxes in human lens epithelial cells (LECs) in hyposmotic solutions. Total ion fluxes, Na-K pump, Cl-dependent Na-K-2Cl (NKCC), K-Cl (KCC) cotransport, and K channels were determined by 85Rb uptake and cell K (Kc) by atomic absorption spectrophotometry, and cell water gravimetrically after exposure to ouabain +/- bumetanide (Na-K pump and NKCC inhibitors), and ion channel inhibitors in varying osmolalities with Na, K, or methyl-d-glucamine and Cl, sulfamate, or nitrate. Reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analyses, and immunochemistry were also performed. In isosmotic (300 mosM) media approximately 90% of the total Rb influx occurred through the Na-K pump and NKCC and approximately 10% through KCC and a residual leak. Hyposmotic media (150 mosM) decreased K(c) by a 16-fold higher K permeability and cell water, but failed to inactivate NKCC and activate KCC. Sucrose replacement or extracellular K to >57 mM, but not Rb or Cs, in hyposmotic media prevented Kc and water loss. Rb influx equaled Kc loss, both blocked by clotrimazole (IC50 approximately 25 microM) and partially by 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) inhibitors of the IK channel KCa3.1 but not by other K channel or connexin hemichannel blockers. Of several anion channel blockers (dihydro-indenyl)oxy]alkanoic acid (DIOA), 4-2(butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)oxybutyric acid (DCPIB), and phloretin totally or partially inhibited Kc loss and Rb influx, respectively. RT-PCR and immunochemistry confirmed the presence of KCa3.1 channels, aside of the KCC1, KCC2, KCC3 and KCC4 isoforms. Apparently, IK channels, possibly in parallel with volume-sensitive outwardly rectifying Cl channels, effect regulatory volume decrease in LECs.

Bumetanide increases Cl--dependent short-circuit current in late distal colon: Evidence for the presence of active electrogenic Cl- absorption.

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Tang, Lieqi; Fang, Xiefan; Winesett, Steven P; Cheng, Catherine Y; Binder, Henry J; Rivkees, Scott A; Cheng, Sam X

2017-01-01

Mammalian colonic epithelia consist of cells that are capable of both absorbing and secreting Cl-. The present studies employing Ussing chamber technique identified two opposing short-circuit current (Isc) responses to basolateral bumetanide in rat distal colon. Apart from the transepithelial Cl--secretory Isc in early distal colon that was inhibited by bumetanide, bumetanide also stimulated Isc in late distal colon that had not previously been identified. Since bumetanide inhibits basolateral Na+-K+-2Cl- cotransporter (NKCC) in crypt cells and basolateral K+-Cl- cotransporter (KCC) in surface epithelium, we proposed this stimulatory Isc could represent a KCC-mediated Cl- absorptive current. In support of this hypothesis, ion substitution experiments established Cl- dependency of this absorptive Isc and transport inhibitor studies demonstrated the involvement of an apical Cl- conductance. Current distribution and RNA sequencing analyses revealed that this Cl- absorptive Isc is closely associated with epithelial Na+ channel (ENaC) but is not dependent on ENaC activity. Thus, inhibition of ENaC by 10 μM amiloride or benzamil neither altered the direction nor its activity. Physiological studies suggested that this Cl- absorptive Isc senses dietary Cl- content; thus when dietary Cl- was low, Cl- absorptive Isc was up-regulated. In contrast, when dietary Cl- was increased, Cl- absorptive Isc was down-regulated. We conclude that an active Cl- extrusion mechanism exists in ENaC-expressing late distal colon and likely operates in parallel with ENaC to facilitate NaCl absorption.

Signal transduction mechanisms of K+-Cl- cotransport regulation and relationship to disease.

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Adragna, N C; Ferrell, C M; Zhang, J; Di Fulvio, M; Temprana, C F; Sharma, A; Fyffe, R E W; Cool, D R; Lauf, P K

2006-01-01

The K+-Cl- cotransport (COT) regulatory pathways recently uncovered in our laboratory and their implication in disease state are reviewed. Three mechanisms of K+-Cl- COT regulation can be identified in vascular cells: (1) the Li+-sensitive pathway, (2) the platelet-derived growth factor (PDGF)-sensitive pathway and (3) the nitric oxide (NO)-dependent pathway. Ion fluxes, Western blotting, semi-quantitative RT-PCR, immunofluorescence and confocal microscopy were used. Li+, used in the treatment of manic depression, stimulates volume-sensitive K+-Cl- COT of low K+ sheep red blood cells at cellular concentrations 3 mM, causes cell swelling, and appears to regulate K+-Cl- COT through a protein kinase C-dependent pathway. PDGF, a potent serum mitogen for vascular smooth muscle cells (VSMCs), regulates membrane transport and is involved in atherosclerosis. PDGF stimulates VSM K+-Cl- COT in a time- and concentration-dependent manner, both acutely and chronically, through the PDGF receptor. The acute effect occurs at the post-translational level whereas the chronic effect may involve regulation through gene expression. Regulation by PDGF involves the signalling molecules phosphoinositides 3-kinase and protein phosphatase-1. Finally, the NO/cGMP/protein kinase G pathway, involved in vasodilation and hence cardiovascular disease, regulates K+-Cl- COT in VSMCs at the mRNA expression and transport levels. A complex and diverse array of mechanisms and effectors regulate K+-Cl- COT and thus cell volume homeostasis, setting the stage for abnormalities at the genetic and/or regulatory level thus effecting or being affected by various pathological conditions.

Phosphorylation and transport in the Na-K-2Cl cotransporters, NKCC1 and NKCC2A, compared in HEK-293 cells.

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Anke Hannemann

2011-03-01

Full Text Available Na-K-2Cl cotransporters help determine cell composition and volume. NKCC1 is widely distributed whilst NKCC2 is only found in the kidney where it plays a vital role reabsorbing 20% of filtered NaCl. NKCC2 regulation is poorly understood because of its restricted distribution and difficulties with its expression in mammalian cell cultures. Here we compare phosphorylation of the N-termini of the cotransporters, measured with phospho-specific antibodies, with bumetanide-sensitive transport of K(+ ((86Rb(+ (activity in HEK-293 cells stably expressing fNKCC1 or fNKCC2A which were cloned from ferret kidney. Activities of transfected transporters were distinguished from those of endogenous ones by working at 37 °C. fNKCC1 and fNKCC2A activities were highest after pre-incubation of cells in hypotonic low-[Cl(-] media to reduce cell [Cl(-] and volume during flux measurement. Phosphorylation of both transporters more than doubled. Pre-incubation with ouabain also strongly stimulated fNKCC1 and fNKCC2A and substantially increased phosphorylation, whereas pre-incubation in Na(+-free media maximally stimulated fNKCC1 and doubled its phosphorylation, but inhibited fNKCC2A, with a small increase in its phosphorylation. Kinase inhibitors halved phosphorylation and activity of both transporters whereas inhibition of phosphatases with calyculin A strongly increased phosphorylation of both transporters but only slightly stimulated fNKCC1 and inhibited fNCCC2A. Thus kinase inhibition reduced phosphorylation and transport, and transport stimulation was only seen when phosphorylation increased, but transport did not always increase with phosphorylation. This suggests phosphorylation of the N-termini determines the transporters' potential capacity to move ions, but final activity also depends on other factors. Transport cannot be reliably inferred solely using phospho-specific antibodies on whole-cell lysates.

Phosphorylation and transport in the Na-K-2Cl cotransporters, NKCC1 and NKCC2A, compared in HEK-293 cells.

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Hannemann, Anke; Flatman, Peter W

2011-03-25

Na-K-2Cl cotransporters help determine cell composition and volume. NKCC1 is widely distributed whilst NKCC2 is only found in the kidney where it plays a vital role reabsorbing 20% of filtered NaCl. NKCC2 regulation is poorly understood because of its restricted distribution and difficulties with its expression in mammalian cell cultures. Here we compare phosphorylation of the N-termini of the cotransporters, measured with phospho-specific antibodies, with bumetanide-sensitive transport of K(+) ((86)Rb(+)) (activity) in HEK-293 cells stably expressing fNKCC1 or fNKCC2A which were cloned from ferret kidney. Activities of transfected transporters were distinguished from those of endogenous ones by working at 37 °C. fNKCC1 and fNKCC2A activities were highest after pre-incubation of cells in hypotonic low-[Cl(-)] media to reduce cell [Cl(-)] and volume during flux measurement. Phosphorylation of both transporters more than doubled. Pre-incubation with ouabain also strongly stimulated fNKCC1 and fNKCC2A and substantially increased phosphorylation, whereas pre-incubation in Na(+)-free media maximally stimulated fNKCC1 and doubled its phosphorylation, but inhibited fNKCC2A, with a small increase in its phosphorylation. Kinase inhibitors halved phosphorylation and activity of both transporters whereas inhibition of phosphatases with calyculin A strongly increased phosphorylation of both transporters but only slightly stimulated fNKCC1 and inhibited fNCCC2A. Thus kinase inhibition reduced phosphorylation and transport, and transport stimulation was only seen when phosphorylation increased, but transport did not always increase with phosphorylation. This suggests phosphorylation of the N-termini determines the transporters' potential capacity to move ions, but final activity also depends on other factors. Transport cannot be reliably inferred solely using phospho-specific antibodies on whole-cell lysates.

Internal magnesium, 2,3-diphosphoglycerate, and the regulation of the steady-state volume of human red blood cells by the Na/K/2Cl cotransport system

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1992-01-01

This study is concerned with the relationship between the Na/K/Cl cotransport system and the steady-state volume (MCV) of red blood cells. Cotransport rate was determined in unfractionated and density- separated red cells of different MCV from different donors to see whether cotransport differences contribute to the difference in the distribution of MCVs. Cotransport, studied in cells at their original MCVs, was determined as the bumetanide (10 microM)-sensitive 22Na efflux in the presence of ouabain (50 microM) after adjusting cellular Na (Nai) and Ki to achieve near maximal transport rates. This condition was chosen to rule out MCV-related differences in Nai and Ki that might contribute to differences in the net chemical driving force for cotransport. We found that in both unfractionated and density-separated red cells the cotransport rate was inversely correlated with MCV. MCV was correlated directly with red cell 2,3-diphosphoglycerate (DPG), whereas total red cell Mg was only slightly elevated in cells with high MCV. Thus intracellular free Mg (Mgifree) is evidently lower in red cells with high 2,3-DPG (i.e., high MCV) and vice versa. Results from flux measurements at their original MCVs, after altering Mgifree with the ionophore A23187, indicated a high Mgi sensitivity of cotransport: depletion of Mgifree inhibited and an elevation of Mgifree increased the cotransport rate. The apparent K0.5 for Mgifree was approximately 0.4 mM. Maximizing Mgifree at optimum Nai and Ki minimized the differences in cotransport rates among the different donors. It is concluded that the relative cotransport rate is regulated for cells in the steady state at their original cell volume, not by the number of copies of the cotransporter but by differences in Mgifree. The interindividual differences in Mgifree, determined primarily by differences in the 2,3-DPG content, are responsible for the differences in the relative cotransport activity that results in an inverse relationship

Potassium-chloride cotransporter 3 interacts with Vav2 to synchronize the cell volume decrease response with cell protrusion dynamics.

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Adèle Salin-Cantegrel

Full Text Available Loss-of-function of the potassium-chloride cotransporter 3 (KCC3 causes hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC, a severe neurodegenerative disease associated with defective midline crossing of commissural axons in the brain. Conversely, KCC3 over-expression in breast, ovarian and cervical cancer is associated with enhanced tumor cell malignancy and invasiveness. We identified a highly conserved proline-rich sequence within the C-terminus of the cotransporter which when mutated leads to loss of the KCC3-dependent regulatory volume decrease (RVD response in Xenopus Laevis oocytes. Using SH3 domain arrays, we found that this poly-proline motif is a binding site for SH3-domain containing proteins in vitro. This approach identified the guanine nucleotide exchange factor (GEF Vav2 as a candidate partner for KCC3. KCC3/Vav2 physical interaction was confirmed using GST-pull down assays and immuno-based experiments. In cultured cervical cancer cells, KCC3 co-localized with the active form of Vav2 in swelling-induced actin-rich protruding sites and within lamellipodia of spreading and migrating cells. These data provide evidence of a molecular and functional link between the potassium-chloride co-transporters and the Rho GTPase-dependent actin remodeling machinery in RVD, cell spreading and cell protrusion dynamics, thus providing new insights into KCC3's involvement in cancer cell malignancy and in corpus callosum agenesis in HMSN/ACC.

[Computation of the K+, Na+ and Cl- fluxes through plasma membrane of animal cell with Na+/K+ pump, NKCC, NC cotransporters, and ionic channels with and without non-Goldman rectification in K+ channels. Norma and apoptosis].

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Rubashkin, A A; Iurinskaia, V E; Vereninov, A A

2010-01-01

The balance of K+, Na+ and Cl- fluxes through cell membrane with the Na+/K+ pump, ion channels and NKCC and NC cotransporters is considered. It is shown that all unidirectional K+, Na+ and Cl- fluxes through cell membrane, permeability coefficients of ion channels and membrane potential can be computed for balanced ion distribution between cell and the medium if K+, Na+ and Cl- concentration in cell water and three fluxes are known: total Cl- flux, total K+ influx and ouabain-inhibitable "pump" component of the K+ influx. Changes in the mortovalent ion balance in lymphoid cells U937 induced to apoptosis by 1 microM staurosporine are analyzed as an example. It is found that the apoptotic shift in ion and water balance in studied cells is caused by a decrease in the pump activity which is accompanied by a decrease in the integral permeability of Na+ channels without significant increase in K+ and Cl- channel permeabilities. Computation shows that only a small part of the total fluxes of K+, Na+ and Cl- accounts for the fluxes via NKCC and NC cotransporters. Therefore, cotransport fluxes can not be studied using inhibitors.

Nitric oxide signaling pathway regulates potassium chloride cotransporter-1 mRNA expression in vascular smooth muscle cells.

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Di Fulvio, M; Lauf, P K; Adragna, N C

2001-11-30

Rat vascular smooth muscle cells (VSMCs) express at least two mRNAs for K-Cl cotransporters (KCC): KCC1 and KCC3. cGMP-dependent protein kinase I regulates KCC3 mRNA expression in these cells. Here, we show evidence implicating the nitric oxide (NO)/cGMP signaling pathway in the expression of KCC1 mRNA, considered to be the major cell volume regulator. VSMCs, expressing soluble guanylyl cyclase (sGC) and PKG-I isoforms showed a time- and concentration-dependent increase in KCC1 mRNA levels after treatment with sodium nitroprusside as demonstrated by semiquantitative RT-PCR. sGC-dependent regulation of KCC1 mRNA expression was confirmed using YC-1, a NO-independent sGC stimulator. The sGC inhibitor LY83583 blocked the effects of sodium nitroprusside and YC-1. Moreover, 8-Br-cGMP increased KCC1 mRNA expression in a concentration- and time-dependent fashion. The 8-Br-cGMP effect was partially blocked by KT5823 but not by actinomycin D. However, actinomycin D and cycloheximide increased basal KCC1 mRNA in an additive manner, suggesting different mechanisms of action for both drugs. These findings suggest that in VSMCs, the NO/cGMP-signaling pathway participates in KCC1 mRNA regulation at the post-transcriptional level.

Cotransport of water by Na¿-K¿-2Cl¿ cotransporters expressed in Xenopus oocytes

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Zeuthen, Thomas; Macaulay, Nanna

2012-01-01

The NKCC1 and NKCC2 isoforms of the mammalian Na¿–K¿–2Cl¿ cotransporter were expressed in Xenopus oocytes and the relation between external ion concentration and water fluxes determined.Water fluxes were determined from changes in the oocytes volume and ion fluxes from 86Rb+ uptake. Isotonic...

Differential expression of gill Na⁺,K⁺-ATPase alpha- and beta-subunits, Na⁺,K⁺,2Cl^- cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar

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Nilsen, Tom O.; Ebbesson, Lars O. E.; Madsen, Steffen S.

2007-01-01

This study examines changes in gill Na(+),K(+)-ATPase (NKA) alpha- and beta-subunit isoforms, Na(+),K(+),2Cl(-) cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR I and II) in anadromous and landlocked strains of Atlantic salmon during parr-smolt transformation, an...

ROS activate KCl cotransport in nonadherent Ehrlich ascites cells but K⁺ and Cl^- channels in adherent Ehrlich Lettré and NIH3T3 cells

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Lambert, Ian Henry; Klausen, Thomas Kjær; Bergdahl, Andreas

2009-01-01

Addition of H2O2 (0.5 mM) to Ehrlich ascites tumor cells under isotonic conditions results within 25 min in a substantial (22 +/- 1 %) reduction in cell volume. The cell shrinkage is paralleled by net loss of K(+), which was significant within 8 min, whereas no concomitant increase in the K......(+) or Cl(-) conductances could be observed. The H2O2-induced cell shrinkage was unaffected by the presence of clofilium and clotrimazole, that block volume-sensitive and Ca(2+)-activated K(+) channels, respectively, and unaffected by a raise in extracellular K(+) concentration to a value which eliminates...... the electrochemical driving force for K(+). On the other hand, the H2O2-induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor DIOA, following substitution of NO3(-) for Cl(-), and when the driving force for KCl cotransport was omitted. It is suggested that H2O2 activates electro neutral...

Physiology and pathophysiology of Na+/H+ exchange and Na+-K+-2Cl- cotransport in the heart, brain, and blood

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Pedersen, S. F.; O´Donnell, M. E.; Anderson, S. E.

2006-01-01

Maintenance of a stable cell volume and intracellular pH is critical for normal cell function. Arguably, two of the most important ion transporters involved in these processes are the Na+/H+ exchanger isoform 1 (NHE1) and Na+-K+-2Cl- cotransporter isoform 1 (NKCC1). Both NHE1 and NKCC1....... The aim is to provide a comprehensive overview of the mechanisms and consequences of stress-induced stimulation of these transporters with focus on the heart, brain, and blood. The physiological stressors reviewed are metabolic/exercise stress, osmotic stress, and mechanical stress, conditions in which...... are stimulated by cell shrinkage and by numerous other stimuli, including a wide range of hormones and growth factors, and for NHE1, intracellular acidification. Both transporters can be important regulators of cell volume, yet their activity also, directly or indirectly, affects the intracellular concentrations...

New aspects of cellular thallium uptake: Tl+-Na+-2Cl--cotransport is the central mechanism of ion uptake

International Nuclear Information System (INIS)

Sessler, M.J.; Maul, F.D.; Hoer, G.; Munz, D.L.; Geck, P.

1986-01-01

Cellular uptake mechanisms of 201 Tl + were studied in Ehrlich mouse ascites tumor cells. 201 Tl + phases the cell membrane of tumor cells using three transport systems: the ATPase, the Tl + -Na + -2Cl - -cotransport, and the Ca ++ -dependent ion channel. In the case of 201 Tl + the main route for entering the cells was the cotransport, its importance increasing with the age of the cells; in parallel, the ATPase activity was reduced. In contrast, the transport capacities of the ATPase and the cotransport were of the same magnitude in the case of 42 K + and 86 Rb + . This change in ion distribution was not brought about by varying velocity relations but by changing the number of transport systems in the cell membrane. There was no relationship between transport rates and diameters of the ions. 201 Tl + distribution is proportional to that of K + with a higher intracellular concentration of about 30%. Under physiological conditions the cotransport was reversible suggesting the ability to regulate steady state during varying extracellular ion concentrations. Cells and medium were two compartments, kinetically seen. Due to the significant difference of transport capacities between the three systems with the respective ions the term ''potassium-thallium-analogy'' may be misleading as it erroneously assumes identical uptake conditions. (orig.) [de

KCl cotransport regulation and protein kinase G in cultured vascular smooth muscle cells.

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Adragna, N C; Zhang, J; Di Fulvio, M; Lincoln, T M; Lauf, P K

2002-05-15

K-Cl cotransport is activated by vasodilators in erythrocytes and vascular smooth muscle cells and its regulation involves putative kinase/phosphatase cascades. N-ethylmaleimide (NEM) activates the system presumably by inhibiting a protein kinase. Nitrovasodilators relax smooth muscle via cGMP-dependent activation of protein kinase G (PKG), a regulator of membrane channels and transporters. We investigated whether PKG regulates K-Cl cotransport activity or mRNA expression in normal, PKG-deficient-vector-only-transfected (PKG-) and PKG-catalytic-domain-transfected (PKG+) rat aortic smooth muscle cells. K-Cl cotransport was calculated as the Cl-dependent Rb influx, and mRNA was determined by semiquantitative RT-PCR. Baseline K-Cl cotransport was higher in PKG+ than in PKG- cells (p <0.01). At 0.5 mM, NEM stimulated K-Cl cotransport by 5-fold in PKG- but not in PKG+ cells. However, NEM was more potent although less effective to activate K-Cl cotransport in normal (passage 1-3) and PKG+ than in PKG- cells. In PKG- cells, [(dihydroindenyl) oxy] alkanoic acid (300 mM) but not furosemide (1 mM) inhibited K-Cl cotransport. Furthermore, no difference in K-Cl cotransport mRNA expression was observed between these cells. In conclusion, this study shows that manipulation of PKG expression in vascular smooth muscle cells affects K-Cl cotransport activity and its activation by NEM.

Canonical Bcl-2 motifs of the Na+/K+ pump revealed by the BH3 mimetic chelerythrine: early signal transducers of apoptosis?

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Lauf, Peter K; Heiny, Judith; Meller, Jarek; Lepera, Michael A; Koikov, Leonid; Alter, Gerald M; Brown, Thomas L; Adragna, Norma C

2013-01-01

Chelerythrine [CET], a protein kinase C [PKC] inhibitor, is a prop-apoptotic BH3-mimetic binding to BH1-like motifs of Bcl-2 proteins. CET action was examined on PKC phosphorylation-dependent membrane transporters (Na+/K+ pump/ATPase [NKP, NKA], Na+-K+-2Cl+ [NKCC] and K+-Cl- [KCC] cotransporters, and channel-supported K+ loss) in human lens epithelial cells [LECs]. K+ loss and K+ uptake, using Rb+ as congener, were measured by atomic absorption/emission spectrophotometry with NKP and NKCC inhibitors, and Cl- replacement by NO3ˉ to determine KCC. 3H-Ouabain binding was performed on a pig renal NKA in the presence and absence of CET. Bcl-2 protein and NKA sequences were aligned and motifs identified and mapped using PROSITE in conjunction with BLAST alignments and analysis of conservation and structural similarity based on prediction of secondary and crystal structures. CET inhibited NKP and NKCC by >90% (IC50 values ~35 and ~15 μM, respectively) without significant KCC activity change, and stimulated K+ loss by ~35% at 10-30 μM. Neither ATP levels nor phosphorylation of the NKA α1 subunit changed. 3H-ouabain was displaced from pig renal NKA only at 100 fold higher CET concentrations than the ligand. Sequence alignments of NKA with BH1- and BH3-like motifs containing pro-survival Bcl-2 and BclXl proteins showed more than one BH1-like motif within NKA for interaction with CET or with BH3 motifs. One NKA BH1-like motif (ARAAEILARDGPN) was also found in all P-type ATPases. Also, NKA possessed a second motif similar to that near the BH3 region of Bcl-2. Findings support the hypothesis that CET inhibits NKP by binding to BH1-like motifs and disrupting the α1 subunit catalytic activity through conformational changes. By interacting with Bcl-2 proteins through their complementary BH1- or BH3-like-motifs, NKP proteins may be sensors of normal and pathological cell functions, becoming important yet unrecognized signal transducers in the initial phases of apoptosis. CET

WNK1/HSN2 mutation in human peripheral neuropathy deregulates KCC2 expression and posterior lateral line development in zebrafish (Danio rerio.

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Valérie Bercier

Full Text Available Hereditary sensory and autonomic neuropathy type 2 (HSNAII is a rare pathology characterized by an early onset of severe sensory loss (all modalities in the distal limbs. It is due to autosomal recessive mutations confined to exon "HSN2" of the WNK1 (with-no-lysine protein kinase 1 serine-threonine kinase. While this kinase is well studied in the kidneys, little is known about its role in the nervous system. We hypothesized that the truncating mutations present in the neural-specific HSN2 exon lead to a loss-of-function of the WNK1 kinase, impairing development of the peripheral sensory system. To investigate the mechanisms by which the loss of WNK1/HSN2 isoform function causes HSANII, we used the embryonic zebrafish model and observed strong expression of WNK1/HSN2 in neuromasts of the peripheral lateral line (PLL system by immunohistochemistry. Knocking down wnk1/hsn2 in embryos using antisense morpholino oligonucleotides led to improper PLL development. We then investigated the reported interaction between the WNK1 kinase and neuronal potassium chloride cotransporter KCC2, as this transporter is a target of WNK1 phosphorylation. In situ hybridization revealed kcc2 expression in mature neuromasts of the PLL and semi-quantitative RT-PCR of wnk1/hsn2 knockdown embryos showed an increased expression of kcc2 mRNA. Furthermore, overexpression of human KCC2 mRNA in embryos replicated the wnk1/hsn2 knockdown phenotype. We validated these results by obtaining double knockdown embryos, both for wnk1/hsn2 and kcc2, which alleviated the PLL defects. Interestingly, overexpression of inactive mutant KCC2-C568A, which does not extrude ions, allowed a phenocopy of the PLL defects. These results suggest a pathway in which WNK1/HSN2 interacts with KCC2, producing a novel regulation of its transcription independent of KCC2's activation, where a loss-of-function mutation in WNK1 induces an overexpression of KCC2 and hinders proper peripheral sensory nerve

Effects of cortisol and salinity acclimation on Na+/K+/2Cl–- cotransporter gene expression and Na+, K+-ATPase activity in the gill of Persian sturgeon, Acipenser persicus, fry

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Saber Khodabandeh

2009-10-01

Full Text Available Na+, K+-ATPase activity and Na+/K+/2Cl–- cotransporter (NKCC gene expression in the gills of Persian sturgeon, Acipenser persicus, fry (2-3 g, 3.30-8.12 cm total body length in freshwater (control group, diluted Caspian Sea water (5 ppt and after treatment with cortisol in freshwater were studied. Na+, K+-ATPase activity was lower in the 5 ppt-acclimated fish (1.07±0.05 _mol Pi/mg protein/h than in the control fish (1.19±0.05 μmol Pi/mg protein/h but this difference was not significant. nKCC gene expression in the 5 ppt-acclimated fish (1.6±0.07 was significantly higher than in the control fish (0.8±0.00. In the cortisol treated fish, Na+, K+-ATPase activity (1.91±0.05 μmol Pi/mg protein/h and NKCC gene expression (3.2±0.1 were significantly higher than in the control group. our results show that Persian sturgeon fry (2-3 g can tolerate 5 ppt salinity by changing their enzymatic content and activity, and that exogenous cortisol application can increase the osmoregulatory capacity of fry before release into brackish water and can reduce their mortality.

NONOates regulate KCl cotransporter-1 and -3 mRNA expression in vascular smooth muscle cells.

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Di Fulvio, Mauricio; Lauf, Peter K; Shah, Shalin; Adragna, Norma C

2003-05-01

Nitric oxide (NO) donors regulate KCl cotransport (KCC) activity and cotransporter-1 and -3 (KCC1 and KCC3) mRNA expression in sheep erythrocytes and in primary cultures of rat vascular smooth muscle cells (VSMCs), respectively. In this study, we used NONOates as rapid and slow NO releasers to provide direct evidence implicating NO as a regulator of KCC3 gene expression at the mRNA level. In addition, we used the expression of KCC3 mRNA to further investigate the mechanism of action of these NO donors at the cellular level. Treatment of VSMCs with rapid NO releasers, like NOC-5 and NOC-9, as well as with the direct NO-independent soluble guanylyl cyclase (sGC) stimulator YC-1, acutely increased KCC3 mRNA expression in a concentration- and time-dependent manner. The slow NO releaser NOC-18 had no effect on KCC3 gene expression. A specific NO scavenger completely prevented the NONOate-induced KCC3 mRNA expression. Inhibition of sGC with LY-83583 blocked the NONOate- and YC-1-induced KCC3 mRNA expression. This study shows that in primary cultures of rat VSMCs, the fast NO releasers NOC-9 and NOC-5, but not the slow NO releaser NOC-18, acutely upregulate KCC3 mRNA expression in a NO/sGC-dependent manner.

Epigenetic suppression of potassium-chloride co-transporter 2 expression in inflammatory pain induced by complete Freund's adjuvant (CFA).

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Lin, C-R; Cheng, J-K; Wu, C-H; Chen, K-H; Liu, C-K

2017-02-01

Multiple mechanisms contribute to the stimulus-evoked pain hypersensitivity that may be experienced after peripheral inflammation. Persistent pathological stimuli in many pain conditions affect the expression of certain genes through epigenetic alternations. The main purpose of our study was to investigate the role of epigenetic modification on potassium-chloride co-transporter 2 (KCC2) gene expression in the persistence of inflammatory pain. Persistent inflammatory pain was induced through the injection of complete Freund's adjuvant (CFA) in the left hind paw of rats. Acetyl-histone H3 and H4 level was determined by chromatin immunoprecipitation in the spinal dorsal horn. Pain behaviour and inhibitory synaptic function of spinal cord were determined before and after CFA injection. KCC2 expression was determined by real time RT-PCR and Western blot. Intrathecal KCC2 siRNA (2 μg per 10 μL per rat) or HDAC inhibitor (10 μg per 10 μL per rat) was injected once daily for 3 days before CFA injection. Persistent inflammatory pain epigenetically suppressed KCC2 expression through histone deacetylase (HDAC)-mediated histone hypoacetylation, resulting in decreased inhibitory signalling efficacy. KCC2 knock-down caused by intrathecal administration of KCC2 siRNA in naïve rats reduced KCC2 expression in the spinal cord, leading to sensitized pain behaviours and impaired inhibitory synaptic transmission in their spinal cords. Moreover, intrathecal HDAC inhibitor injection in CFA rats increased KCC2 expression, partially restoring the spinal inhibitory synaptic transmission and relieving the sensitized pain behaviour. These findings suggest that the transcription of spinal KCC2 is regulated by histone acetylation epigenetically following CFA. Persistent pain suppresses KCC2 expression through HDAC-mediated histone hypoacetylation and consequently impairs the inhibitory function of inhibitory interneurons. Drugs such as HDAC inhibitors that suppress the influences of

Regulation of potassium transport in human lens epithelial cells.

Science.gov (United States)

Lauf, Peter K; Warwar, Ronald; Brown, Thomas L; Adragna, Norma C

2006-01-01

The major K influx pathways and their response to thiol modification by N-ethylmaleimide (NEM) and protein kinase and phosphatase inhibitors were characterized in human lens epithelial B3 (HLE-B3) cells with Rb as K congener. Ouabain (0.1 mM) and bumetanide (5 microM) discriminated between the Na/K pump ( approximately 35% of total Rb influx) and Na-K-2Cl cotransport (NKCC) ( approximately 50%). Cl-replacement with nitrate or sulfamate revealed 100 microM, activated the Na/K pump and abolished NKCC but did not affect KCC. The data suggest at least partial inverse regulation of KCC and NKCC in HLE-B3 cells by signaling cascades involving serine, threonine and tyrosine phosphorylation/dephosphorylation equilibria.

Canonical Bcl-2 Motifs of the Na+/K+ Pump Revealed by the BH3 Mimetic Chelerythrine: Early Signal Transducers of Apoptosis?

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Peter K. Lauf

2013-02-01

Full Text Available Background/Aims: Chelerythrine [CET], a protein kinase C [PKC] inhibitor, is a prop-apoptotic BH3-mimetic binding to BH1-like motifs of Bcl-2 proteins. CET action was examined on PKC phosphorylation-dependent membrane transporters (Na+/K+ pump/ATPase [NKP, NKA], Na+-K+-2Cl+ [NKCC] and K+-Cl- [KCC] cotransporters, and channel-supported K+ loss in human lens epithelial cells [LECs]. Methods: K+ loss and K+ uptake, using Rb+ as congener, were measured by atomic absorption/emission spectrophotometry with NKP and NKCC inhibitors, and Cl- replacement by NO3ˉ to determine KCC. 3H-Ouabain binding was performed on a pig renal NKA in the presence and absence of CET. Bcl-2 protein and NKA sequences were aligned and motifs identified and mapped using PROSITE in conjunction with BLAST alignments and analysis of conservation and structural similarity based on prediction of secondary and crystal structures. Results: CET inhibited NKP and NKCC by >90% (IC50 values ∼35 and ∼15 µM, respectively without significant KCC activity change, and stimulated K+ loss by ∼35% at 10-30 µM. Neither ATP levels nor phosphorylation of the NKA α1 subunit changed. 3H-ouabain was displaced from pig renal NKA only at 100 fold higher CET concentrations than the ligand. Sequence alignments of NKA with BH1- and BH3-like motifs containing pro-survival Bcl-2 and BclXl proteins showed more than one BH1-like motif within NKA for interaction with CET or with BH3 motifs. One NKA BH1-like motif (ARAAEILARDGPN was also found in all P-type ATPases. Also, NKA possessed a second motif similar to that near the BH3 region of Bcl-2. Conclusion: Findings support the hypothesis that CET inhibits NKP by binding to BH1-like motifs and disrupting the α1 subunit catalytic activity through conformational changes. By interacting with Bcl-2 proteins through their complementary BH1- or BH3-like-motifs, NKP proteins may be sensors of normal and pathological cell functions, becoming important yet

Dexmedetomidine attenuates persistent postsurgical pain by upregulating K+–Cl− cotransporter-2 in the spinal dorsal horn in rats

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Dai S

2018-05-01

Full Text Available Shuhong Dai,1 Yu Qi,1 Jie Fu,1 Na Li,1 Xu Zhang,1 Juan Zhang,2 Wei Zhang,2 Haijun Xu,1 Hai Zhou,1 Zhengliang Ma2 1Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China; 2The Affiliated Nanjing Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China Background: Dexmedetomidine (DEX could have an analgesic effect on pain transmission through the modulation of brain-derived neurotrophic factor (BDNF. In addition, KCC2-induced shift in neuronal Cl- homeostasis is crucial for postsynaptic inhibition mediated by GABAA receptors. Accumulating evidence shows that nerve injury, peripheral inflammation and stress activate the spinal BDNF/TrkB signal, which results in the downregulation of KCC2 transport and expression, eventually leads to GAGAergic disinhibition and hyperalgesia. The aim of this experiment was to explore the interaction between DEX and KCC2 at a molecular level in rats in the persistent postsurgical pain (PPSP. Methods: PPSP in rats was evoked by the skin/muscle incision and retraction (SMIR. Mechanical hypersensitivity was assessed with the Dynamic Plantar Aesthesiometer. Western blot and immunofluorescence assay were used to assess the expressions of related proteins. Results: In the first part of our experiment, the results revealed that the BDNF/TrkB-KCC2 signal plays a critical role in the development of SMIR-evoked PPSP; the second part showed that intraperitoneal administrations of 40 µg/kg DEX at 15 min presurgery and 1 to 3 days post-surgery significantly attenuated SMIR-evoked PPSP. Simultaneously, SMIR-induced KCC2 downregulation was partly reversed, which coincided with the inhibition of the BDNF/TrkB signal in the spinal dorsal horn. Moreover, intrathecal administrations of KCC2 inhibitor VU0240551 significantly reduced the analgesic effect of DEX on SMIR-evoked PPSP. Conclusion: The results of our study indicated that DEX attenuated PPSP by restoring KCC2 function through reducing BDNF

Distal truncation of KCC3 in non-French Canadian HMSN/ACC families.

NARCIS (Netherlands)

Salin-Cantegrel, A.; Riviere, J.B.; Dupre, N.; Charron, F.M.; Shekarabi, M.; Karemera, L.; Gaspar, C.; Horst, J. van der; Tekin, M.; Deda, G.; Krause, A.; Lippert, M.M.; Willemsen, M.A.A.P.; Jarrar, R.; Lapointe, J.Y.; Rouleau, G.A.

2007-01-01

BACKGROUND: Hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC) is a severe and progressive autosomal recessive polyneuropathy. Mutations in the potassium-chloride cotransporter 3 gene (KCC3) were identified as responsible for HMSN/ACC in the French Canadian (FC)

The ClC-K2 Chloride Channel Is Critical for Salt Handling in the Distal Nephron.

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Hennings, J Christopher; Andrini, Olga; Picard, Nicolas; Paulais, Marc; Huebner, Antje K; Cayuqueo, Irma Karen Lopez; Bignon, Yohan; Keck, Mathilde; Cornière, Nicolas; Böhm, David; Jentsch, Thomas J; Chambrey, Régine; Teulon, Jacques; Hübner, Christian A; Eladari, Dominique

2017-01-01

Chloride transport by the renal tubule is critical for blood pressure (BP), acid-base, and potassium homeostasis. Chloride uptake from the urinary fluid is mediated by various apical transporters, whereas basolateral chloride exit is thought to be mediated by ClC-Ka/K1 and ClC-Kb/K2, two chloride channels from the ClC family, or by KCl cotransporters from the SLC12 gene family. Nevertheless, the localization and role of ClC-K channels is not fully resolved. Because inactivating mutations in ClC-Kb/K2 cause Bartter syndrome, a disease that mimics the effects of the loop diuretic furosemide, ClC-Kb/K2 is assumed to have a critical role in salt handling by the thick ascending limb. To dissect the role of this channel in detail, we generated a mouse model with a targeted disruption of the murine ortholog ClC-K2. Mutant mice developed a Bartter syndrome phenotype, characterized by renal salt loss, marked hypokalemia, and metabolic alkalosis. Patch-clamp analysis of tubules isolated from knockout (KO) mice suggested that ClC-K2 is the main basolateral chloride channel in the thick ascending limb and in the aldosterone-sensitive distal nephron. Accordingly, ClC-K2 KO mice did not exhibit the natriuretic response to furosemide and exhibited a severely blunted response to thiazide. We conclude that ClC-Kb/K2 is critical for salt absorption not only by the thick ascending limb, but also by the distal convoluted tubule. Copyright © 2016 by the American Society of Nephrology.

Expression of three isoforms of Na-K-2Cl cotransporter (NKCC2) in the kidney and regulation by dehydration.

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Itoh, Kazuko; Izumi, Yuichiro; Inoue, Takeaki; Inoue, Hideki; Nakayama, Yushi; Uematsu, Takayuki; Fukuyama, Takashi; Yamazaki, Taiga; Yasuoka, Yukiko; Makino, Takeshi; Nagaba, Yasushi; Tomita, Kimio; Kobayashi, Noritada; Kawahara, Katsumasa; Mukoyama, Masashi; Nonoguchi, Hiroshi

2014-10-24

Sodium reabsorption via Na-K-2Cl cotransporter 2 (NKCC2) in the thick ascending limbs has a major role for medullary osmotic gradient and subsequent water reabsorption in the collecting ducts. We investigated intrarenal localization of three isoforms of NKCC2 mRNA expressions and the effects of dehydration on them in rats. To further examine the mechanisms of dehydration, the effects of hyperosmolality on NKCC2 mRNA expression in microdissected renal tubules was studied. RT-PCR and RT-competitive PCR were employed. The expressions of NKCC2a and b mRNA were observed in the cortical thick ascending limbs (CAL) and the distal convoluted tubules (DCT) but not in the medullary thick ascending limbs (MAL), whereas NKCC2f mRNA expression was seen in MAL and CAL. Two-day dehydration did not affect these mRNA expressions. In contrast, hyperosmolality increased NKCC2 mRNA expression in MAL in vitro. Bradykinin dose-dependently decreased NKCC2 mRNA expression in MAL. However, dehydration did not change NKCC2 protein expression in membrane fraction from cortex and outer medulla and in microdissected MAL. These data show that NKCC2a/b and f types are mainly present in CAL and MAL, respectively. Although NKCC2 mRNA expression was stimulated by hyperosmolality in vitro, NKCC2 mRNA and protein expressions were not stimulated by dehydration in vivo. These data suggest the presence of the inhibitory factors for NKCC2 expression in dehydration. Considering the role of NKCC2 for the countercurrent multiplier system, NKCC2f expressed in MAL might be more important than NKCC2a/b. Copyright © 2014 Elsevier Inc. All rights reserved.

Regulation of the sodium/potassium/chloride cotransporter by calcium and cyclic AMP in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Higgins, B.L.; Smith, L.; Smith, J.B.

1987-01-01

The activity of the Na/K/Cl cotransporter in smooth muscle cells cultured from rat aorta was assayed by measuring the initial rate of furosemide-inhibitable 86 Rb influx or efflux. Five uM furosemide or 0.2 uM bumetanide inhibited influx by 50%. Furosemide-inhibitable 86 Rb influx depended on the presence of all 3 ions in the external medium. The dependence on Na and K was hyperbolic with apparent Km values of 45 and 5 mM, respectively. The dependence on Cl was sigmoidal. Assuming a stoichiometry of 1:1:2 for Na:K:Cl, a Km for Cl of 60 mM was obtained from a Hofstee plot of the data. Rapidly growing cells had 3 fold higher cotransport activity than quiescent cells. Angiotensin II (ANG) stimulated furosemide-inhibitable 86 Rb efflux by 2 fold. An ANG receptor antagonist prevented ANG from increasing cotransport activity. Two calcium ionophores, A23187 and ionomycin, increased cotransport activity by 2 fold. Phorbol myristate acetate had no effect on cotransport activity. Isoproterenol, dibutyryl cyclic AMP, cholera toxin, or methylisobutylxanthine inhibited furosemide-sensitive 86 Rb influx by 35 to 50%. From these findings they conclude that increasing cytoplasmic free calcium stimulates cotransport activity, whereas increasing cellular cyclic AMP inhibits the cotransporter

Renal-Specific Silencing of TNF (Tumor Necrosis Factor) Unmasks Salt-Dependent Increases in Blood Pressure via an NKCC2A (Na+-K+-2Cl- Cotransporter Isoform A)-Dependent Mechanism.

Science.gov (United States)

Hao, Shoujin; Hao, Mary; Ferreri, Nicholas R

2018-06-01

We tested the hypothesis that TNF (tumor necrosis factor)-α produced within the kidney and acting on the renal tubular system is part of a regulatory mechanism that attenuates increases in blood pressure in response to high salt intake. Intrarenal administration of a lentivirus construct, which specifically silenced TNF in the kidney, did not affect baseline blood pressure. However, blood pressure increased significantly 1 day after mice with intrarenal silencing of TNF ingested 1% NaCl in the drinking water. The increase in blood pressure, which was continuously observed for 11 days, promptly returned to baseline levels when mice were switched from 1% NaCl to tap water. Silencing of renal TNF also increased NKCC2 (Na + -K + -2Cl - cotransporter) phosphorylation and induced a selective increase in NKCC2A (NKCC2 isoform A) mRNA accumulation in both the cortical and medullary thick ascending limb of Henle loop that was neither associated with a compensatory decrease of NKCC2F in the medulla nor NKCC2B in the cortex. The NaCl-mediated increases in blood pressure were completely absent when NKCC2A, using a lentivirus construct that did not alter expression of NKCC2F or NKCC2B, and TNF were concomitantly silenced in the kidney. Moreover, the decrease in urine volume and NaCl excretion induced by renal TNF silencing was abolished when NKCC2A was concurrently silenced, suggesting that this isoform contributes to the transition from a salt-resistant to salt-sensitive phenotype. Collectively, the data are the first to demonstrate a role for TNF produced by the kidney in the modulation of sodium homeostasis and blood pressure regulation. © 2018 American Heart Association, Inc.

KCC2-dependent Steady-state Intracellular Chloride Concentration and pH in Cortical Layer 2/3 Neurons of Anesthetized and Awake Mice

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Juan C. Boffi

2018-01-01

Full Text Available Neuronal intracellular Cl− concentration ([Cl−]i influences a wide range of processes such as neuronal inhibition, membrane potential dynamics, intracellular pH (pHi or cell volume. Up to date, neuronal [Cl−]i has predominantly been studied in model systems of reduced complexity. Here, we implemented the genetically encoded ratiometric Cl− indicator Superclomeleon (SCLM to estimate the steady-state [Cl−]i in cortical neurons from anesthetized and awake mice using 2-photon microscopy. Additionally, we implemented superecliptic pHluorin (SE-pHluorin as a ratiometric sensor to estimate the intracellular steady-state pH (pHi of mouse cortical neurons in vivo. We estimated an average resting [Cl−]i of 6 ± 2 mM with no evidence of subcellular gradients in the proximal somato-dendritic domain and an average somatic pHi of 7.1 ± 0.2. Neither [Cl−]i nor pHi were affected by isoflurane anesthesia. We deleted the cation-Cl− co-transporter KCC2 in single identified neurons of adult mice and found an increase of [Cl−]i to approximately 26 ± 8 mM, demonstrating that under in vivo conditions KCC2 produces low [Cl−]i in adult mouse neurons. In summary, neurons of the brain of awake adult mice exhibit a low and evenly distributed [Cl−]i in the proximal somato-dendritic compartment that is independent of anesthesia and requires KCC2 expression for its maintenance.

In vitro studies of theophylline-induced changes in Na, K and Cl transport in hen (Gallus domesticus) colon suggesting bidirectional, basolateral NaK2Cl cotransport

DEFF Research Database (Denmark)

Andersen, Vibeke; Munck, B G; Munck, L K

1990-01-01

1. In isolated mucosa from a NaCl-loaded hen theophylline stimulates both unidirectional chloride fluxes (JmsCl and JsmCl). Conductive and electroneutral exchange processes, besides a bumetanide-sensitive, rheogenic process contribute. 2. The bumetanide-sensitive fraction of the theophylline......-induced delta JcmCl is sodium-dependent. 3. Incubation in nominally K(+)-free solutions reduces the bumetanide-sensitive fraction delta JsmCl more than treatment with ouabain. 4. With respect to chloride the bumetanide-sensitive fraction of delta JsmCl has a Hill coefficient of 1.93 +/- 0.03, a Jmax of 12...

Regulatory domain or CpG site variation in SLC12A5, encoding the chloride transporter KCC2, in human autism and schizophrenia

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Nancy D Merner

2015-10-01

Full Text Available Many encoded gene products responsible for neurodevelopmental disorders (NDs like autism spectrum disorders (ASD, schizophrenia (SCZ, intellectual disability (ID, and idiopathic generalized epilepsy (IGE converge on networks controlling synaptic function. An increase in KCC2 (SLC12A5 Cl- transporter activity drives the developmental GABA excitatory-inhibitory sequence, but the role of KCC2 in human NDs is essentially unknown. Here, we report two rare, non-synonymous (NS, functionally-impairing variants in the KCC2 C-terminal regulatory domain (CTRD in human ASD (R952H and R1049C and SCZ (R952H previously linked with IGE and familial febrile seizures, and another novel NS KCC2 variant in ASD (R1048W with highly-predicted pathogenicity. Exome data from 2517 simplex families in the ASD Simon Simplex Collection revealed significantly more KCC2 CTRD variants in ASD cases than controls, and interestingly, these were more often synonymous and predicted to disrupt or introduce a CpG site. Furthermore, full gene analysis showed ASD cases are more likely to contain rare KCC2 variants affecting CpG sites than controls. These data suggest genetically-encoded dysregulation of KCC2-dependent GABA signaling may contribute to multiple human NDs.

The Role of Na:K:2Cl Cotransporter 1 (NKCC1/SLC12A2) in Dental Epithelium during Enamel Formation in Mice

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Jalali, Rozita; Lodder, Johannes C.; Zandieh-Doulabi, Behrouz; Micha, Dimitra; Melvin, James E.; Catalan, Marcelo A.; Mansvelder, Huibert D.; DenBesten, Pamela; Bronckers, Antonius

2017-01-01

Na+:K+:2Cl− cotransporters (NKCCs) belong to the SLC12A family of cation-coupled Cl− transporters. We investigated whether enamel-producing mouse ameloblasts express NKCCs. Transcripts for Nkcc1 were identified in the mouse dental epithelium by RT-qPCR and NKCC1 protein was immunolocalized in outer enamel epithelium and in the papillary layer but not the ameloblast layer. In incisors of Nkcc1-null mice late maturation ameloblasts were disorganized, shorter and the mineral density of the enamel was reduced by 10% compared to wild-type controls. Protein levels of gap junction protein connexin 43, Na+-dependent bicarbonate cotransporter e1 (NBCe1), and the Cl−-dependent bicarbonate exchangers SLC26A3 and SLC26A6 were upregulated in Nkcc1-null enamel organs while the level of NCKX4/SLC24A4, the major K+, Na+ dependent Ca2+ transporter in maturation ameloblasts, was slightly downregulated. Whole-cell voltage clamp studies on rat ameloblast-like HAT-7 cells indicated that bumetanide increased ion-channel activity conducting outward currents. Bumetanide also reduced cell volume of HAT-7 cells. We concluded that non-ameloblast dental epithelium expresses NKCC1 to regulate cell volume in enamel organ and provide ameloblasts with Na+, K+ and Cl− ions required for the transport of mineral- and bicarbonate-ions into enamel. Absence of functional Nkcc1 likely is compensated by other types of ion channels and ion transporters. The increased amount of Cx43 in enamel organ cells in Nkcc1-null mice suggests that these cells display a higher number of gap junctions to increase intercellular communication. PMID:29209227

Effectiveness of ketogenic diet in pentylenetetrazol-induced and kindling rats as well as its potential mechanisms.

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Wang, Shan; Ding, Yao; Ding, Xiao-Yan; Liu, Zhi-Rong; Shen, Chun-Hong; Jin, Bo; Guo, Yi; Wang, Shuang; Ding, Mei-Ping

2016-02-12

The effects and mechanisms of ketogenic diets (KD) are unclear. In this study, we aimed to reveal electrographic and behavioral thresholds in responses to the KD in pentylenetetrazol (PTZ)-induced seizures, as well as its antiepileptogenic effects on PTZ-kindling rats. Additionally, we investigated the potential link between KD and expression levels of two cation chloride co-transporters: K(+)-Cl(-) co-transporter 2 (KCC2) and Na(+)-K(+)-Cl(-) co-transporter 1 (NKCC1). The KD group had significantly higher electrographic thresholds than the control (ND) group for the first spike-and-wave, subcontinuous spike-and-wave, high amplitude spike-and-wave, and polyspikes both in the cortex and hippocampus. Compared to the ND group, the KD group had higher behavioral thresholds for behavioral absence, first jerk, first overt myoclonia, and generalized seizures. In the PTZ-kindling model, KD not only prolonged the latency of myoclonic and clonic convulsions, but shortened clonic and generalized duration. In addition, KD rats had higher KCC2 protein expression before kindling, during myoclonic jerks, and GTCS compared with ND rats. There were no significant differences in NKCC1 protein levels between both groups following the four-week dietary intervention without PTZ exposure (before kindling). Moreover, KD inhibited the upregulation of NKCC1 expression induced by kindling in myoclonic jerks and GTCS. Therefore, our findings demonstrated that KD had antiepileptic features in elevating thresholds to most electrographic and behavioral seizure patterns in PTZ-induced rats, as well as delaying the progression and alleviating the severity of seizure in PTZ-kindling model. The antiepileptogenic effects of KD may be attributed to its regulatory properties on KCC2 and NKCC1 protein expression. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Abnormal expression of cerebrospinal fluid cation chloride cotransporters in patients with Rett syndrome.

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Sofia Temudo Duarte

Full Text Available OBJECTIVE: Rett Syndrome is a progressive neurodevelopmental disorder caused mainly by mutations in the gene encoding methyl-CpG-binding protein 2. The relevance of MeCP2 for GABAergic function was previously documented in animal models. In these models, animals show deficits in brain-derived neurotrophic factor, which is thought to contribute to the pathogenesis of this disease. Neuronal Cation Chloride Cotransporters (CCCs play a key role in GABAergic neuronal maturation, and brain-derived neurotrophic factor is implicated in the regulation of CCCs expression during development. Our aim was to analyse the expression of two relevant CCCs, NKCC1 and KCC2, in the cerebrospinal fluid of Rett syndrome patients and compare it with a normal control group. METHODS: The presence of bumetanide sensitive NKCC1 and KCC2 was analysed in cerebrospinal fluid samples from a control pediatric population (1 day to 14 years of life and from Rett syndrome patients (2 to 19 years of life, by immunoblot analysis. RESULTS: Both proteins were detected in the cerebrospinal fluid and their levels are higher in the early postnatal period. However, Rett syndrome patients showed significantly reduced levels of KCC2 and KCC2/NKCC1 ratio when compared to the control group. CONCLUSIONS: Reduced KCC2/NKCC1 ratio in the cerebrospinal fluid of Rett Syndrome patients suggests a disturbed process of GABAergic neuronal maturation and open up a new therapeutic perspective.

Regulation of the Na(+)-K(+)-2Cl(-) cotransporter by cGMP/cGMP-dependent protein kinase I after furosemide administration.

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Limmer, Franziska; Schinner, Elisabeth; Castrop, Hayo; Vitzthum, Helga; Hofmann, Franz; Schlossmann, Jens

2015-10-01

Sodium chloride reabsorption in the thick ascending limb of the loop of Henle is mediated by the Na(+)-K(+)-2Cl(-) cotransporter (NKCC2). The loop diuretic furosemide is a potent inhibitor of NKCC2. However, less is known about the mechanism regulating the electrolyte transporter. Considering the well-established effects of nitric oxide on NKCC2 activity, cGMP is likely involved in this regulation. cGMP-dependent protein kinase I (cGKI; PKGI) is a cGMP target protein that phosphorylates different substrates after activation through cGMP. We investigated the potential correlation between the cGMP/cGKI pathway and NKCC2 regulation. We treated wild-type (wt) and cGKIα-rescue mice with furosemide. cGKIα-rescue mice expressed cGKIα only under the control of the smooth muscle-specific transgelin (SM22) promoter in a cGKI deficient background. Furosemide treatment increased the urine excretion of sodium and chloride in cGKIα-rescue mice compared to that in wt mice. We analyzed the phosphorylation of NKCC2 by western blotting and immunostaining using the phosphospecific antibody R5. The administration of furosemide significantly increased the phosphorylated NKCC2 signal in wt but not in cGKIα-rescue mice. NKCC2 activation led to its phosphorylation and membrane translocation. To examine whether cGKI was involved in this process, we analyzed vasodilator-stimulated phosphoprotein, which is phosphorylated by cGKI. Furosemide injection resulted in increased vasodilator-stimulated phosphoprotein phosphorylation in wt mice. We hypothesize that furosemide administration activated cGKI, leading to NKCC2 phosphorylation and membrane translocation. This cGKI-mediated pathway could be a mechanism to compensate for the inhibitory effect of furosemide on NKCC2. © 2015 FEBS.

Regulation of the Na+2Cl–K+ cotransporter in in vitro perfused rectal gland tubules of Squalus acanthias.

Science.gov (United States)

Warth, R; Bleich, M; Thiele, I; Lang, F; Greger, R

1998-07-01

Previously it has been shown that the Na+2Cl–K+ cotransporter accepts NH4 + at its K+ binding site. This property can be used to estimate its transport rates by adding NH4 + to the bath and measuring the initial furosemide-dependent rates of change in BCECF fluorescence. We have utilized this technique to determine the regulation of the furosemide-inhibitable Na+2Cl–K+ cotransporter in in vitroperfused rectal gland tubules (RGT) of Squalus acanthias. Addition of NH4 + to the bath (20 mmol/l) led to an initial alkalinization, corresponding to NH3 uptake. This was followed by an acidification, corresponding to NH4 + uptake. The rate of this uptake was quantified by exponential curve fitting and is given in arbitrary units (Δfluorescence/time). This acidification could be completely inhibited by furosemide. In the absence of any secretagogue preincubation of RGT in a low Cl– solution (6 mmol/l, low Cl–) for 10 min enhanced the uptake rate significantly from 4.04±0.51 to 12.7±1.30 (n=5). The addition of urea (200 mmol/l) was without effect, but the addition of 300 mmol/l mannitol (+300 mannitol) enhanced the rate significantly from 7.24±1.33 to 14.7±4.6 (n=6). Stimulation of NaCl secretion by a solution maximizing the cytosolic cAMP concentration (Stim) led to a significant increase in NH4 + uptake rate from 5.00±1.33 to 13.3±1.54 (n=6). Similar results were obtained in the additional presence of Ba2+ (1 mmol/l): the uptake rate was increased significantly from 4.23±0.34 to 15.1±1.86 (n=16). In the presence of Stim low Cl– had no additional effect on the uptake rate: 15.1±3.1 versus 15.2±2.8 in high Cl– (n=6). The uptake rate in Stim containing additional +300 mannitol (22.3±4.0, n=5) was not significantly different from that obtained with Stim or +300 mannitol alone. By whatever mechanism the NH4 + uptake rate was increased furosemide (500 µmol/l) always reduced this rate to control values. Hence three manoeuvres enhanced furosemide

Mini-review: regulation of the renal NaCl cotransporter by hormones.

Science.gov (United States)

Rojas-Vega, Lorena; Gamba, Gerardo

2016-01-01

The renal thiazide-sensitive NaCl cotransporter, NCC, is the major pathway for salt reabsorption in the distal convoluted tubule. The activity of this cotransporter is critical for regulation of several physiological variables such as blood pressure, serum potassium, acid base metabolism, and urinary calcium excretion. Therefore, it is not surprising that numerous hormone-signaling pathways regulate NCC activity to maintain homeostasis. In this review, we will provide an overview of the most recent evidence on NCC modulation by aldosterone, angiotensin II, vasopressin, glucocorticoids, insulin, norepinephrine, estradiol, progesterone, prolactin, and parathyroid hormone. Copyright © 2016 the American Physiological Society.

General anaesthetics do not impair developmental expression of the KCC2 potassium-chloride cotransporter in neonatal rats during the brain growth spurt

KAUST Repository

Lacoh, Claudia Marvine; Bodogan, T.; Kaila, Kai K.; Fiumelli, Hubert; Vutskits, Lá szló

2013-01-01

. However, it is not known whether early neuronal activity plays a modulatory role in the expression of total KCC2 mRNA and protein in the immature brain. As general anaesthetics are powerful modulators of neuronal activity, the purpose of this study

Ablation of Potassium-Chloride Cotransporter Type 3 (Kcc3) in Mouse Causes Multiple Cardiovascular Defects and Isosmotic Polyuria.

Science.gov (United States)

Garneau, Alexandre P; Marcoux, Andrée-Anne; Noël, Micheline; Frenette-Cotton, Rachelle; Drolet, Marie-Claude; Couet, Jacques; Larivière, Richard; Isenring, Paul

2016-01-01

Inactivation of Kcc3 in a mixed 129/Sv×C57BL/6 mouse background has been previously found to increase systemic blood pressure (BP) through presumed neurogenic mechanisms. Yet, while this background is generally not considered ideal to investigate the cardiovascular system, KCC3 is also expressed in the arterial wall and proximal nephron. In the current study, the effects of Kcc3 ablation was investigated in a pure rather than mixed C57BL/6J background under regular- and high-salt diets to determine whether they could be mediated through vasculogenic and nephrogenic mechanisms. Aortas were also assessed for reactivity to pharmacological agents while isolated from the influence of sympathetic ganglia. This approach led to the identification of unforeseen abnormalities such as lower pulse pressure, heart rate, aortic reactivity and aortic wall thickness, but higher diastolic BP, left ventricular mass and urinary output in the absence of increased catecholamine levels. Salt loading also led systolic BP to be higher, but to no further changes in hemodynamic parameters. Importantly, aortic vascular smooth muscle cells and cardiomyocytes were both found to express KCC3 abundantly in heterozygous mice. Hence, Kcc3 inactivation in our model caused systemic vascular resistance and ventricular mass to increase while preventing extracellular fluid volume to accumulate. Given that it also affected the physiological properties of aortas in vitro, vasculogenic mechanisms could therefore account for a number of the hemodynamic abnormalities observed.

Mechanisms of hyposmotic volume regulation in isolated nematocytes of the anthozoan Aiptasia diaphana.

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Marino, Angela; Morabito, Rossana; La Spada, Giuseppina; Adragna, Norma C; Lauf, Peter K

2010-01-01

The nature and role of potassium (K) and water transport mediating hyposmotically-induced regulatory volume decrease (RVD) were studied in nematocytes dissociated with 605 mM thiocyanate from acontia of the Anthozoan Aiptasia diaphana. Cell volume and hence RVD were calculated from the inverse ratios of the cross sectional areas of nematocytes (A/A(o)) measured before (A(o)) and after (A) challenge with 65% artificial sea water (ASW). To distinguish between K channels and K-Cl cotransport (KCC), external sodium (Na) and chloride (Cl) were replaced by K and nitrate (NO(3)), respectively. Inhibitors were added to identify K channels (barium, Ba), and putative kinase (N-ethylmaleimide, NEM) and phosphatase (okadaic acid, OA) regulation of KCC. In 65% NaCl ASW, nematocytes displayed a biphasic change in A/A(o), peaking within 4 min due to osmotic water entry and thereafter declining within 6 min due to RVD. Changing NaCl to KCl or NaNO(3) ASW did not affect the osmotic phase but attenuated RVD, consistent with K channel and KCC mechanisms. Ba (3 mM) inhibited RVD. NEM and OA, applied separately, inhibited the osmotic phase and muted RVD suggesting primary action on water transport (aquaporins). NEM and OA together reduced the peak A/A(o) ratio during the osmotic phase whereas RVD was inhibited when OA preceded NEM. Thus, both K channels and KCC partake in the nematocyte RVD, the extent of which is determined by functional thiols and dephosphorylation of putative aquaporins facilitating the preceding osmotic water shifts. Copyright 2010 S. Karger AG, Basel.

Functional expression of the Na-K-2Cl cotransporter NKCC2 in mammalian cells fails to confirm the dominant-negative effect of the AF splice variant.

Science.gov (United States)

Hannemann, Anke; Christie, Jenny K; Flatman, Peter W

2009-12-18

The renal bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) is the major salt transport pathway in the apical membrane of the mammalian thick ascending limb. It is differentially spliced and the three major variants (A, B, and F) differ in their localization and transport characteristics. Most knowledge about its regulation comes from experiments in Xenopus oocytes as NKCC2 proved difficult to functionally express in a mammalian system. Here we report the cloning and functional expression of untagged and unmodified versions of the major splice variants from ferret kidney (fNKCC2A, -B, and -F) in human embryonic kidney (HEK) 293 cells. Many NKCC2 antibodies used in this study detected high molecular weight forms of the transfected proteins, probably NKCC2 dimers, but not the monomers. Interestingly, monomers were strongly detected by phosphospecific antibodies directed against phosphopeptides in the regulatory N terminus. Bumetanide-sensitive (86)Rb uptake was significantly higher in transfected HEK-293 cells and could be stimulated by incubating cells in a medium containing a low chloride concentration prior the uptake measurements. fNKCC2 was less sensitive to the reduction in chloride concentration than NKCC1. Using HEK-293 cells stably expressing fNKCC2A we also show that co-expression of variant NKCC2AF does not have the dominant-negative effect on NKCC2A activity that was seen in Xenopus oocytes, nor is it trafficked to the cell surface. In addition, fNKCC2AF is neither complex glycosylated nor phosphorylated in its N terminus regulatory region like other variants.

Mutation of the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 in mice is associated with severe polyuria and a urea-selective concentrating defect without hyperreninemia.

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Kemter, Elisabeth; Rathkolb, Birgit; Bankir, Lise; Schrewe, Anja; Hans, Wolfgang; Landbrecht, Christina; Klaften, Matthias; Ivandic, Boris; Fuchs, Helmut; Gailus-Durner, Valérie; Hrabé de Angelis, Martin; Wolf, Eckhard; Wanke, Ruediger; Aigner, Bernhard

2010-06-01

The bumetanide-sensitive Na(+)-K(+)-2Cl(-) cotransporter NKCC2, located in the thick ascending limb of Henle's loop, plays a critical role in the kidney's ability to concentrate urine. In humans, loss-of-function mutations of the solute carrier family 12 member 1 gene (SLC12A1), coding for NKCC2, cause type I Bartter syndrome, which is characterized by prenatal onset of a severe polyuria, salt-wasting tubulopathy, and hyperreninemia. In this study, we describe a novel chemically induced, recessive mutant mouse line termed Slc12a1(I299F) exhibiting late-onset manifestation of type I Bartter syndrome. Homozygous mutant mice are viable and exhibit severe polyuria, metabolic alkalosis, marked increase in plasma urea but close to normal creatininemia, hypermagnesemia, hyperprostaglandinuria, hypotension,, and osteopenia. Fractional excretion of urea is markedly decreased. In addition, calcium and magnesium excretions are more than doubled compared with wild-type mice, while uric acid excretion is twofold lower. In contrast to hyperreninemia present in human disease, plasma renin concentration in homozygotes is not increased. The polyuria observed in homozygotes may be due to the combination of two additive factors, a decrease in activity of mutant NKCC2 and an increase in medullary blood flow, due to prostaglandin-induced vasodilation, that impairs countercurrent exchange of urea in the medulla. In conclusion, this novel viable mouse line with a missense Slc12a1 mutation exhibits most of the features of type I Bartter syndrome and may represent a new model for the study of this human disease.

Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase, Na +/K+/2Cl- cotransporter and CFTR anion channel

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Hiroi, J.; McCormick, S.D.; Ohtani-Kaneko, R.; Kaneko, T.

2005-01-01

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins, Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K +-ATPase staining; type II, basolateral Na+/K +-ATPase and apical NKCC; type III, basolateral Na+/K +-ATPase and basolateral NKCC; type IV, basolateral Na +/K+-ATPase, basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.

A sea urchin Na(+)K(+)2Cl(-) cotransporter is involved in the maintenance of calcification-relevant cytoplasmic cords in Strongylocentrotus droebachiensis larvae.

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Basse, Wiebke C; Gutowska, Magdalena A; Findeisen, Ulrike; Stumpp, Meike; Dupont, Sam; Jackson, Daniel J; Himmerkus, Nina; Melzner, Frank; Bleich, Markus

2015-09-01

The cellular mechanisms of calcification in sea urchin larvae are still not well understood. Primary mesenchyme cells within the larval body cavity form a syncytium to secrete CaCO3 spicules from intracellular amorphous CaCO3 (ACC) stores. We studied the role of Na(+)K(+)2Cl(-) cotransporter (NKCC) in intracellular ACC accumulation and larval spicule formation of Strongylocentrotus droebachiensis. First, we incubated growing larvae with three different loop diuretics (azosemide, bumetanide, and furosemide) and established concentration-response curves. All loop diuretics were able to inhibit calcification already at concentrations that specifically inhibit NKCC. Calcification was most effectively inhibited by azosemide (IC50=6.5 μM), while larval mortality and swimming ability were not negatively impacted by the treatment. The inhibition by bumetanide (IC50=26.4 μM) and furosemide (IC50=315.4 μM) resembled the pharmacological fingerprint of the mammalian NKCC1 isoform. We further examined the effect of azosemide on the maintenance of cytoplasmic cords and on the occurrence of calcification vesicles using fluorescent dyes (calcein, FM1-43). Fifty micromolars of azosemide inhibited the maintenance of cytoplasmic cords and resulted in increased calcein fluorescence within calcification vesicles. The expression of NKCC in S. droebachiensis was verified by PCR and Western blot with a specific NKCC antibody. In summary, the pharmacological profile of loop diuretics and their specific effects on calcification in sea urchin larvae suggest that they act by inhibition of NKCC via repression of cytoplasmic cord formation and maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

Age-dependent susceptibility to phenobarbital-resistant neonatal seizures: role of chloride co-transporters

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Seok Kyu eKang

2015-05-01

Full Text Available Ischemia in the immature brain is an important cause of neonatal seizures. Temporal evolution of acquired neonatal seizures and their response to anticonvulsants are of great interest, given the unreliability of the clinical correlates and poor efficacy of first-line anti-seizure drugs. The expression and function of the electroneutral chloride co-transporters KCC2 and NKCC1 influence the anti-seizure efficacy of GABAA-agonists. To investigate ischemia-induced seizure susceptibility and efficacy of the GABAA-agonist phenobarbital (PB, with NKCC1 antagonist bumetanide (BTN as an adjunct treatment, we utilized permanent unilateral carotid-ligation to produce acute ischemic-seizures in postnatal day 7, 10 and 12 CD1 mice. Immediate post-ligation video-electroencephalograms (EEGs quantitatively evaluated baseline and post-treatment seizure burdens. Brains were examined for stroke-injury and western blot analyses to evaluate the expression of KCC2 and NKCC1. Severity of acute ischemic seizures post-ligation was highest at P7. PB was an efficacious anti-seizure agent at P10 and P12, but not at P7. BTN failed as an adjunct, at all ages tested and significantly blunted PB-efficacy at P10. Significant acute post-ischemic downregulation of KCC2 was detected at all ages. At P7, males displayed higher age-dependent seizure susceptibility, associated with a significant developmental lag in their KCC2 expression. This study established a novel neonatal mouse model of PB-resistant seizures that demonstrates age/sex-dependent susceptibility. The age-dependent profile of KCC2 expression and its post-insult downregulation may underlie the PB-resistance reported in this model. Blocking NKCC1 with low-dose BTN following PB treatment failed to improve PB-efficacy.

Human NKCC2 cation–Cl– co-transporter complements lack of Vhc1 transporter in yeast vacuolar membranes.

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Petrezselyova, Silvia; Dominguez, Angel; Herynkova, Pavla; Macias, Juan F; Sychrova, Hana

2013-10-01

Cation–chloride co-transporters serve to transport Cl– and alkali metal cations. Whereas a large family of these exists in higher eukaryotes, yeasts only possess one cation–chloride co-transporter, Vhc1, localized to the vacuolar membrane. In this study, the human cation–chloride co-transporter NKCC2 complemented the phenotype of VHC1 deletion in Saccharomyces cerevisiae and its activity controlled the growth of salt-sensitive yeast cells in the presence of high KCl, NaCl and LiCl. A S. cerevisiae mutant lacking plasma-membrane alkali–metal cation exporters Nha1 and Ena1-5 and the vacuolar cation–chloride co-transporter Vhc1 is highly sensitive to increased concentrations of alkali–metal cations, and it proved to be a suitable model for characterizing the substrate specificity and transport activity of human wild-type and mutated cation–chloride co-transporters. Copyright © 2013 John Wiley & Sons, Ltd.

Age- and sex-dependent susceptibility to phenobarbital-resistant neonatal seizures: role of chloride co-transporters.

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Kang, Seok Kyu; Markowitz, Geoffrey J; Kim, Shin Tae; Johnston, Michael V; Kadam, Shilpa D

2015-01-01

Ischemia in the immature brain is an important cause of neonatal seizures. Temporal evolution of acquired neonatal seizures and their response to anticonvulsants are of great interest, given the unreliability of the clinical correlates and poor efficacy of first-line anti-seizure drugs. The expression and function of the electroneutral chloride co-transporters KCC2 and NKCC1 influence the anti-seizure efficacy of GABAA-agonists. To investigate ischemia-induced seizure susceptibility and efficacy of the GABAA-agonist phenobarbital (PB), with NKCC1 antagonist bumetanide (BTN) as an adjunct treatment, we utilized permanent unilateral carotid-ligation to produce acute ischemic-seizures in post-natal day 7, 10, and 12 CD1 mice. Immediate post-ligation video-electroencephalograms (EEGs) quantitatively evaluated baseline and post-treatment seizure burdens. Brains were examined for stroke-injury and western blot analyses to evaluate the expression of KCC2 and NKCC1. Severity of acute ischemic seizures post-ligation was highest at P7. PB was an efficacious anti-seizure agent at P10 and P12, but not at P7. BTN failed as an adjunct, at all ages tested and significantly blunted PB-efficacy at P10. Significant acute post-ischemic downregulation of KCC2 was detected at all ages. At P7, males displayed higher age-dependent seizure susceptibility, associated with a significant developmental lag in their KCC2 expression. This study established a novel neonatal mouse model of PB-resistant seizures that demonstrates age/sex-dependent susceptibility. The age-dependent profile of KCC2 expression and its post-insult downregulation may underlie the PB-resistance reported in this model. Blocking NKCC1 with low-dose BTN following PB treatment failed to improve PB-efficacy.

Activity-dependent astrocyte swelling is mediated by pH-regulating mechanisms.

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Larsen, Brian Roland; MacAulay, Nanna

2017-10-01

During neuronal activity in the mammalian brain, the K + released into the synaptic space is initially buffered by the astrocytic compartment. In parallel, the extracellular space (ECS) shrinks, presumably due to astrocytic cell swelling. With the Na + /K + /2Cl - cotransporter and the Kir4.1/AQP4 complex not required for the astrocytic cell swelling in the hippocampus, the molecular mechanisms underlying the activity-dependent ECS shrinkage have remained unresolved. To identify these molecular mechanisms, we employed ion-sensitive microelectrodes to measure changes in ECS, [K + ] o and [H + ] o /pH o during electrical stimulation of rat hippocampal slices. Transporters and receptors responding directly to the K + and glutamate released into the extracellular space (the K + /Cl - cotransporter, KCC, glutamate transporters and G protein-coupled receptors) did not modulate the extracellular space dynamics. The HCO3--transporting mechanism, which in astrocytes mainly constitutes the electrogenic Na + / HCO3- cotransporter 1 (NBCe1), is activated by the K + -mediated depolarization of the astrocytic membrane. Inhibition of this transporter reduced the ECS shrinkage by ∼25% without affecting the K + transients, pointing to NBCe1 as a key contributor to the stimulus-induced astrocytic cell swelling. Inhibition of the monocarboxylate cotransporters (MCT), like-wise, reduced the ECS shrinkage by ∼25% without compromising the K + transients. Isosmotic reduction of extracellular Cl - revealed a requirement for this ion in parts of the ECS shrinkage. Taken together, the stimulus-evoked astrocytic cell swelling does not appear to occur as a direct effect of the K + clearance, as earlier proposed, but partly via the pH-regulating transport mechanisms activated by the K + -induced astrocytic depolarization and the activity-dependent metabolism. © 2017 Wiley Periodicals, Inc.

The Effect of WNK4 on the Na+-Cl- Cotransporter Is Modulated by Intracellular Chloride.

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Bazúa-Valenti, Silvana; Chávez-Canales, María; Rojas-Vega, Lorena; González-Rodríguez, Xochiquetzal; Vázquez, Norma; Rodríguez-Gama, Alejandro; Argaiz, Eduardo R; Melo, Zesergio; Plata, Consuelo; Ellison, David H; García-Valdés, Jesús; Hadchouel, Juliette; Gamba, Gerardo

2015-08-01

It is widely recognized that the phenotype of familial hyperkalemic hypertension is mainly a consequence of increased activity of the renal Na(+)-Cl(-) cotransporter (NCC) because of altered regulation by with no-lysine-kinase 1 (WNK1) or WNK4. The effect of WNK4 on NCC, however, has been controversial because both inhibition and activation have been reported. It has been recently shown that the long isoform of WNK1 (L-WNK1) is a chloride-sensitive kinase activated by a low Cl(-) concentration. Therefore, we hypothesized that WNK4 effects on NCC could be modulated by intracellular chloride concentration ([Cl(-)]i), and we tested this hypothesis in oocytes injected with NCC cRNA with or without WNK4 cRNA. At baseline in oocytes, [Cl(-)]i was near 50 mM, autophosphorylation of WNK4 was undetectable, and NCC activity was either decreased or unaffected by WNK4. A reduction of [Cl(-)]i, either by low chloride hypotonic stress or coinjection of oocytes with the solute carrier family 26 (anion exchanger)-member 9 (SLC26A9) cRNA, promoted WNK4 autophosphorylation and increased NCC-dependent Na(+) transport in a WNK4-dependent manner. Substitution of the leucine with phenylalanine at residue 322 of WNK4, homologous to the chloride-binding pocket in L-WNK1, converted WNK4 into a constitutively autophosphorylated kinase that activated NCC, even without chloride depletion. Elimination of the catalytic activity (D321A or D321K-K186D) or the autophosphorylation site (S335A) in mutant WNK4-L322F abrogated the positive effect on NCC. These observations suggest that WNK4 can exert differential effects on NCC, depending on the intracellular chloride concentration. Copyright © 2015 by the American Society of Nephrology.

Cotransport of sodium and chloride by the adult mammalian choroid plexus

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Johanson, C.E.; Sweeney, S.M.; Parmelee, J.T.; Epstein, M.H. (Brown Univ./Rhode Island Hospital, Providence (USA))

1990-02-01

Cerebrospinal fluid formation stems primarily from the transport of Na and Cl in choroid plexus (CP). To characterize properties and modulation of choroidal transporters, we tested diuretics and other agents for ability to alter ion transport in vitro. Adult Sprague-Dawley rats were the source of CPs preincubated with drug for 20 min and then transferred to cerebrospinal fluid (CSF) medium containing 22Na or 36Cl with (3H)mannitol (extracellular correction). Complete base-line curves were established for cellular uptake of Na and Cl at 37 degrees C. The half-maximal uptake occurred at 12 s, so it was used to assess drug effects on rate of transport (nmol Na or Cl/mg CP). Bumetanide (10(-5) and 10(-4) M) decreased uptake of Na and Cl with maximal inhibition (up to 45%) at 10(-5) M. Another cotransport inhibitor, furosemide (10(-4) M), reduced transport of Na by 25% and Cl by 33%. However, acetazolamide (10(-4) M) and atriopeptin III (10(-7) M) significantly lowered uptake of Na (but not Cl), suggesting effect(s) other than on cotransport. The disulfonic stilbene 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 10(-4) M), known to inhibit Cl-HCO3 exchange, substantially reduced the transport of 36Cl. Bumetanide plus DIDS (both 10(-4) M) caused additive inhibition of 90% of Cl uptake, which provides strong evidence for the existence of both cotransport and antiport Cl carriers. Overall, this in vitro analysis, uncomplicated by variables of blood flow and neural tone, indicates the presence in rat CP of the cotransport of Na and Cl in addition to the established Na-H and Cl-HCO3 exchangers.

Meltability in system of K2TaF7-NaF-NaCl-KCl

International Nuclear Information System (INIS)

Kartsev, V.E.; Kovalev, F.V.; Korshunov, B.G.

1975-01-01

Thermographic and visual-polythermal techniques were used to study the meltability in K 2 TaF 7 -NaF-NaCl-KCl system. The tetrahedron-forming sections NaF-NaCl-K 2 TaF 7 xKCl and NaF-K 2 TaF 7 xKCl-2K 2 TaF 7 xNaCl divide the concentration tetrahedron into three particular tetrahedra: NaF-K 2 TaF 7 xKCl-2K 2 TaF 7 xNaCl-K 2 TaF 7 , NaF-NaCl-K 2 TaF 7 xKCl-2K 2 TaF 7 xaCl, and NaF-NaCl-KCl-K 2 TaF 7 xKCl. Non-variant equilibrium points in all of the particular four-component systems have been determined

Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.

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Kitano, I; Mori, N; Matsunaga, T

1995-03-01

To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.

Effects of low environmental salinity on the cellular profiles and expression of Na+, K+-ATPase and Na+, K+, 2Cl- cotransporter 1 of branchial mitochondrion-rich cells in the juvenile marine fish Monodactylus argenteus.

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Kang, Chao-Kai; Liu, Fu-Chen; Chang, Wen-Been; Lee, Tsung-Han

2012-06-01

The goal of this study was to determine the osmoregulatory ability of a juvenile marine fish, silver moony (Monodactylus argenteus), for the purpose of developing a new experimental species for ecophysiological research. In this study, M. argenteus was acclimated to freshwater (FW), brackish water (BW), or seawater (SW). The salinity tolerance of this euryhaline species was effective, and the fish survived well upon osmotic challenges. The largest apical surface of mitochondrion-rich cells was found in the FW individuals. Immunohistochemical staining revealed that Na(+), K(+)-ATPase immunoreactive (NKA-IR) cells were distributed in the interlamellar region of the gill filaments of the silver moony in all experimental groups. In addition to the filaments, NKA-IR cells were also found in the lamellae of the FW individuals. The number of NKA-IR cells in the gills of the FW individuals exceeded that of the BW and SW individuals. The NKA-IR cells of FW and SW individuals exhibited bigger size than that of BW fish. The NKA activities and protein expression of the NKA α-subunit in the gills of the FW individuals were significantly higher than in the BW and SW groups. Additionally, the relative amounts of Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were salinity-dependent in the gills. Immunofluorescent signals of NKCC1 were localized to the basolateral membrane of NKA-IR cells in all groups. In the gills of the FW individuals, however, some NKA-IR cells did not exhibit a basolateral NKCC1 signal. In conclusion, the present study illustrated the osmoregulatory mechanisms of this easy- and economic-to-rear marine teleost with euryhaline capacity and proved the silver moony to be a good experimental animal.

Selective inhibition of miR-92 in hippocampal neurons alters contextual fear memory.

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Vetere, Gisella; Barbato, Christian; Pezzola, Silvia; Frisone, Paola; Aceti, Massimiliano; Ciotti, MariaTeresa; Cogoni, Carlo; Ammassari-Teule, Martine; Ruberti, Francesca

2014-12-01

Post-transcriptional gene regulation mediated by microRNAs (miRNAs) is implicated in memory formation; however, the function of miR-92 in this regulation is uncharacterized. The present study shows that training mice in contextual fear conditioning produces a transient increase in miR-92 levels in the hippocampus and decreases several miR-92 gene targets, including: (i) the neuronal Cl(-) extruding K(+) Cl(-) co-transporter 2 (KCC2) protein; (ii) the cytoplasmic polyadenylation protein (CPEB3), an RNA-binding protein regulator of protein synthesis in neurons; and (iii) the transcription factor myocyte enhancer factor 2D (MEF2D), one of the MEF2 genes which negatively regulates memory-induced structural plasticity. Selective inhibition of endogenous miR-92 in CA1 hippocampal neurons, by a sponge lentiviral vector expressing multiple sequences imperfectly complementary to mature miR-92 under the control of the neuronal specific synapsin promoter, leads to up-regulation of KCC2, CPEB3 and MEF2D, impairs contextual fear conditioning, and prevents a memory-induced increase in the spine density. Taken together, the results indicate that neuronal-expressed miR-92 is an endogenous fine regulator of contextual fear memory in mice. © 2014 Wiley Periodicals, Inc.

Chemical effects of nuclear transformations in mixed crystals. 7. Chemical effects of the 35Cl(n,γ)36Cl nuclear reaction in K2ReCl6-K2ReBr6 mixed crystals

International Nuclear Information System (INIS)

Mueller, H.; Diefallah, E.H.M.; Martin, S.

1981-01-01

The solid-state reactions occurring during the moderation of recoiling 36 Cl, produced by the (n,γ) reaction, have been studied in K 2 ReCl 6 -K 2 ReBr 6 mixed crystals. The main reaction products are Re 36 ClCl 5 2- , Re 36 ClBr 5 2- , and 36 Cl - , but the more intimately mixed species Re 36 ClCl/sub n/Br/sub 5-n/ 2- (n = 1, 2, 3, 4) are found in significant amounts. The production of the different recoil-labeled species can be explained by elementary impact models: 6% of the recoils do not leave their original lattice site (primary retetion); between 6% and 23%, dependent upon the mixed-crystal composition, appear as interstitials; 31 to 48% give rise to direct displacement reactions of one halide ligand; and 40% produce larger disruption by substitution of at least two halide ligands. The results have been compared with Roessler's 38 Cl recoil experiments

Effects of 5-hydroxymethyl-2-furfural on the volume and membrane permeability of red blood cells from patients with sickle cell disease.

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Hannemann, Anke; Cytlak, Urszula M; Rees, David C; Tewari, Sanjay; Gibson, John S

2014-09-15

The heterocyclic aldehyde 5-hydroxymethyl-2-furfural (5HMF) interacts allosterically with the abnormal form of haemoglobin (Hb), HbS, in red blood cells (RBCs) from patients with sickle cell disease (SCD), thereby increasing oxygen affinity and decreasing HbS polymerization and RBC sickling during hypoxia. We hypothesized that should 5HMF also inhibit the main cation pathways implicated in the dehydration of RBCs from SCD patients - the deoxygenation-induced cation pathway (Psickle), the Ca(2+)-activated K(+) channel (the Gardos channel) and the K(+)-Cl(-) cotransporter (KCC) - it would have a synergistic effect in protection against sickling, directly through interacting with HbS, and indirectly through maintaining hydration and reducing [HbS]. This study was therefore designed to investigate the effects of 5HMF on RBC volume and K(+) permeability in vitro. 5HMF markedly reduced the deoxygenation-induced dehydration of RBCs whether in response to maintained deoxygenation or to cyclical deoxygenation/re-oxygenation. 5HMF was found to inhibit Psickle, an effect which correlated with its effects on sickling. Deoxygenation-induced activation of the Gardos channel and exposure of phosphatidylserine were also inhibited, probably indirectly via reduced entry of Ca(2+) through the Psickle pathway. Effects of 5HMF on KCC were more modest with a slight inhibition in N-ethylmaleimide (NEM, 1 mm)-treated RBCs and stimulation in RBCs untreated with NEM. These findings support the hypothesis that 5HMF may also be beneficial through effects on RBC ion and water homeostasis. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

A Raman spectroscopic study of the structural aspects of K2MgCl4 and Cs2MgCl4 as solid single crystals and molten salts

International Nuclear Information System (INIS)

Brooker, M.H.

1975-01-01

Polarized Raman spectra have been obtained for oriented single crystals of K 2 MgCl 4 and Cs 2 MgCl 4 at 77 and 298 K. The data are in excellent agreement with factor group analyses based on the space groups I 4 /mmm (D 17 4 /subh/) and Pnma (D 16 2 /subh/) for the K 2 MgCl 4 and Cs 2 MgCl 4 crystals. In K 2 MgCl 4 the magnesium is surrounded by six chloride ions in a distorted octahedral arrangement with a network structure such that neighboring octahedra share corners. In Cs 2 MgCl 4 a discrete tetrahedral MgCl 4 2- species is present. The 35 Cl-- 37 Cl isotopic splitting of the symmetric stetching mode of the tetrahedral MgCl 4 2- species has been resolved at 77 K and is similar to that observed for CCl 4 . Raman spectra for the high temperature solids and molten salts suggest that the coordination number of magnesium changes from six in solid K 2 MgCl 4 to four in the melt, whereas Cs 2 MgCl 4 melts with retention of the MgCl 4 2- tetrahedral complex. Additional evidence is presented to support previous reports that the MgCl 4 2- tetrahedral species is the principal complex ion in the melts, although a fraction of the magnesium appears to be present in a polynuclear complex, perhaps Mg 2 Cl 6 2-

Mechanisms of astrocytic K(+) clearance and swelling under high extracellular K(+) concentrations.

Science.gov (United States)

Murakami, Shingo; Kurachi, Yoshihisa

2016-03-01

In response to the elevation of extracellular K(+) concentration ([K(+)]out), astrocytes clear excessive K(+) to maintain conditions necessary for neural activity. K(+) clearance in astrocytes occurs via two processes: K(+) uptake and K(+) spatial buffering. High [K(+)]out also induces swelling in astrocytes, leading to edema and cell death in the brain. Despite the importance of astrocytic K(+) clearance and swelling, the underlying mechanisms remain unclear. Here, we report results from a simulation analysis of astrocytic K(+) clearance and swelling. Astrocyte models were constructed by incorporating various mechanisms such as intra/extracellular ion concentrations of Na(+), K(+), and Cl(-), cell volume, and models of Na,K-ATPase, Na-K-Cl cotransporter (NKCC), K-Cl cotransporter, inwardly-rectifying K(+) (KIR) channel, passive Cl(-) current, and aquaporin channel. The simulated response of astrocyte models under the uniform distribution of high [K(+)]out revealed significant contributions of NKCC and Na,K-ATPase to increases of intracellular K(+) and Cl(-) concentrations, and swelling. Moreover, we found that, under the non-uniform distribution of high [K(+)]out, KIR channels localized at synaptic clefts absorbed excess K(+) by depolarizing the equivalent potential of K(+) (E K) above membrane potential, while K(+) released through perivascular KIR channels was enhanced by hyperpolarizing E K and depolarizing membrane potential. Further analysis of simulated drug effects revealed that astrocyte swelling was modulated by blocking each of the ion channels and transporters. Our simulation analysis revealed controversial mechanisms of astrocytic K(+) clearance and swelling resulting from complex interactions among ion channels and transporters.

Expression of GABA signaling molecules KCC2, NKCC1, and GAD1 in cortical development and schizophrenia.

Science.gov (United States)

Hyde, Thomas M; Lipska, Barbara K; Ali, Towhid; Mathew, Shiny V; Law, Amanda J; Metitiri, Ochuko E; Straub, Richard E; Ye, Tianzhang; Colantuoni, Carlo; Herman, Mary M; Bigelow, Llewellyn B; Weinberger, Daniel R; Kleinman, Joel E

2011-07-27

GABA signaling molecules are critical for both human brain development and the pathophysiology of schizophrenia. We examined the expression of transcripts derived from three genes related to GABA signaling [GAD1 (GAD67 and GAD25), SLC12A2 (NKCC1), and SLC12A5 (KCC2)] in the prefrontal cortex (PFC) and hippocampal formation of a large cohort of nonpsychiatric control human brains (n = 240) across the lifespan (from fetal week 14 to 80 years) and in patients with schizophrenia (n = 30-31), using quantitative RT-PCR. We also examined whether a schizophrenia risk-associated promoter SNP in GAD1 (rs3749034) is related to expression of these transcripts. Our studies revealed that development and maturation of both the PFC and hippocampal formation are characterized by progressive switches in expression from GAD25 to GAD67 and from NKCC1 to KCC2. Previous studies have demonstrated that the former leads to GABA synthesis, and the latter leads to switching from excitatory to inhibitory neurotransmission. In the hippocampal formation, GAD25/GAD67 and NKCC1/KCC2 ratios are increased in patients with schizophrenia, reflecting a potentially immature GABA physiology. Remarkably, GAD25/GAD67 and NKCC1/KCC2 expression ratios are associated with rs3749034 genotype, with risk alleles again predicting a relatively less mature pattern. These findings suggest that abnormalities in GABA signaling critical to brain development contribute to genetic risk for schizophrenia.

Preparation of a novel KCC-1/nylon 6 nanocomposite via electrospinning technique

Energy Technology Data Exchange (ETDEWEB)

Aghakhani, Ali [Material and Energy Research Center, Department of Semiconductors (Iran, Islamic Republic of); Kazemi, Ensiyeh; Kazemzad, Mahmood, E-mail: m-kazemzad@merc.ac.ir [Material and Energy Research Center, Department of Energy (Iran, Islamic Republic of)

2015-10-15

In this research, a novel nanofibrous composite of KCC-1/nylon 6 was prepared using electrospinning techniques. First, fibrous silica nanospheres (KCC-1) were synthesized via conventional polycondensation method with a new solvent system. The scanning electron microscopy (SEM) images showed a spongy spherical morphology with a uniform distribution of particle sizes and an average diameter of around 305 nm. Synthesized KCC-1 nanospheres are considered as mesoporous materials due to their high BET specific surface area of 576 m{sup 2} g{sup −1} and BJH average pore diameter of 3.28 nm. The KCC-1/nylon 6 composite was fabricated by preparing a dispersion of nanosilica (10–50 % w/w) in a solution of nylon 6 (15 % w/v) in formic acid. Upon applying a high voltage, the nonwoven electrospun KCC-1/nylon 6 composite nanofibers were obtained. The KCC-1 nanospheres were arranged in line along the nylon 6 fibers like rosary beads wrapped in the polymer. Based on the SEM images, we obtained a well-distributed nanocomposite even at higher silica content. The prepared KCC-1/nylon 6 composite showed 29–55 % higher BET specific surface area compared with pure nylon 6 nanofibers which makes it a good candidate to be used as a sorbent material for environmental or drug delivery applications.

Accumulation of GABAergic neurons, causing a focal ambient GABA gradient, and downregulation of KCC2 are induced during microgyrus formation in a mouse model of polymicrogyria.

Science.gov (United States)

Wang, Tianying; Kumada, Tatsuro; Morishima, Toshitaka; Iwata, Satomi; Kaneko, Takeshi; Yanagawa, Yuchio; Yoshida, Sachiko; Fukuda, Atsuo

2014-04-01

Although focal cortical malformations are considered neuronal migration disorders, their formation mechanisms remain unknown. We addressed how the γ-aminobutyric acid (GABA)ergic system affects the GABAergic and glutamatergic neuronal migration underlying such malformations. A focal freeze-lesion (FFL) of the postnatal day zero (P0) glutamic acid decarboxylase-green fluorescent protein knock-in mouse neocortex produced a 3- or 4-layered microgyrus at P7. GABAergic interneurons accumulated around the necrosis including the superficial region during microgyrus formation at P4, whereas E17.5-born, Cux1-positive pyramidal neurons outlined the GABAergic neurons and were absent from the superficial layer, forming cell-dense areas in layer 2 of the P7 microgyrus. GABA imaging showed that an extracellular GABA level temporally increased in the GABAergic neuron-positive area, including the necrotic center, at P4. The expression of the Cl(-) transporter KCC2 was downregulated in the microgyrus-forming GABAergic and E17.5-born glutamatergic neurons at P4; these cells may need a high intracellular Cl(-) concentration to induce depolarizing GABA effects. Bicuculline decreased the frequency of spontaneous Ca(2+) oscillations in these microgyrus-forming cells. Thus, neonatal FFL causes specific neuronal accumulation, preceded by an increase in ambient GABA during microgyrus formation. This GABA increase induces GABAA receptor-mediated Ca(2+) oscillation in KCC2-downregulated microgyrus-forming cells, as seen in migrating cells during early neocortical development.

Ameloblast modulation and transport of Cl-, Na+, and K+ during amelogenesis

NARCIS (Netherlands)

Bronckers, A.L.J.J.; Lyaruu, D.; Jalali, R.; Medina, J.F.; Zandieh-Doulabi, B.; DenBesten, P.K.

2015-01-01

Ameloblasts express transmembrane proteins for transport of mineral ions and regulation of pH in the enamel space. Two major transporters recently identified in ameloblasts are the Na+K+-dependent calcium transporter NCKX4 and the Na+-dependent HPO42- (Pi) cotransporter NaPi-2b. To regulate pH,

Mutations in SLC12A5 in epilepsy of infancy with migrating focal seizures

Science.gov (United States)

Stödberg, Tommy; McTague, Amy; Ruiz, Arnaud J.; Hirata, Hiromi; Zhen, Juan; Long, Philip; Farabella, Irene; Meyer, Esther; Kawahara, Atsuo; Vassallo, Grace; Stivaros, Stavros M.; Bjursell, Magnus K.; Stranneheim, Henrik; Tigerschiöld, Stephanie; Persson, Bengt; Bangash, Iftikhar; Das, Krishna; Hughes, Deborah; Lesko, Nicole; Lundeberg, Joakim; Scott, Rod C.; Poduri, Annapurna; Scheffer, Ingrid E.; Smith, Holly; Gissen, Paul; Schorge, Stephanie; Reith, Maarten E. A.; Topf, Maya; Kullmann, Dimitri M.; Harvey, Robert J.; Wedell, Anna; Kurian, Manju A.

2015-01-01

The potassium-chloride co-transporter KCC2, encoded by SLC12A5, plays a fundamental role in fast synaptic inhibition by maintaining a hyperpolarizing gradient for chloride ions. KCC2 dysfunction has been implicated in human epilepsy, but to date, no monogenic KCC2-related epilepsy disorders have been described. Here we show recessive loss-of-function SLC12A5 mutations in patients with a severe infantile-onset pharmacoresistant epilepsy syndrome, epilepsy of infancy with migrating focal seizures (EIMFS). Decreased KCC2 surface expression, reduced protein glycosylation and impaired chloride extrusion contribute to loss of KCC2 activity, thereby impairing normal synaptic inhibition and promoting neuronal excitability in this early-onset epileptic encephalopathy. PMID:26333769

Potassium Supplementation Prevents Sodium Chloride Cotransporter Stimulation During Angiotensin II Hypertension.

Science.gov (United States)

Veiras, Luciana C; Han, Jiyang; Ralph, Donna L; McDonough, Alicia A

2016-10-01

Angiotensin II (AngII) hypertension increases distal tubule Na-Cl cotransporter (NCC) abundance and phosphorylation (NCCp), as well as epithelial Na(+) channel abundance and activating cleavage. Acutely raising plasma [K(+)] by infusion or ingestion provokes a rapid decrease in NCCp that drives a compensatory kaliuresis. The first aim tested whether acutely raising plasma [K(+)] with a single 3-hour 2% potassium meal would lower NCCp in Sprague-Dawley rats after 14 days of AngII (400 ng/kg per minute). The potassium-rich meal neither decreased NCCp nor increased K(+) excretion. AngII-infused rats exhibited lower plasma [K(+)] versus controls (3.6±0.2 versus 4.5±0.1 mmol/L; Pblood pressure did not significantly decrease. Epithelial Na(+) channel subunit abundance and cleavage increased 1.5- to 3-fold in both A1K and A2K; ROMK (renal outer medulla K(+) channel abundance) abundance was unaffected by AngII or dietary K(+) In summary, the accumulation and phosphorylation of NCC seen during chronic AngII infusion hypertension is likely secondary to potassium deficiency driven by epithelial Na(+) channel stimulation. © 2016 American Heart Association, Inc.

High Brain Ammonia Tolerance and Down-Regulation of Na+:K+:2Cl- Cotransporter 1b mRNA and Protein Expression in the Brain of the Swamp Eel, Monopterus albus, Exposed to Environmental Ammonia or Terrestrial Conditions

Science.gov (United States)

Ip, Yuen K.; Hou, Zhisheng; Chen, Xiu L.; Ong, Jasmine L. Y.; Chng, You R.; Ching, Biyun; Hiong, Kum C.; Chew, Shit F.

2013-01-01

Na+:K+:2Cl- cotransporter 1 (NKCC1) has been implicated in mediating ischemia-, trauma- or ammonia-induced astrocyte swelling/brain edema in mammals. This study aimed to determine the effects of ammonia or terrestrial exposure on ammonia concentrations in the plasma and brain, and the mRNA expression and protein abundance of nkcc/Nkcc in the brain, of the swamp eel Monopterus albus . Ammonia exposure led to a greater increase in the ammonia concentration in the brain of M. albus than terrestrial exposure. The brain ammonia concentration of M. albus reached 4.5 µmol g-1 and 2.7 µmol g-1 after 6 days of exposure to 50 mmol l-1 NH4Cl and terrestrial conditions, respectively. The full cDNA coding sequence of nkcc1b from M. albus brain comprised 3276 bp and coded for 1092 amino acids with an estimated molecular mass of 119.6 kDa. A molecular characterization indicated that it could be activated through phosphorylation and/or glycosylation by osmotic and/or oxidative stresses. Ammonia exposure for 1 day or 6 days led to significant decreases in the nkcc1b mRNA expression and Nkcc1b protein abundance in the brain of M. albus. In comparison, a significant decrease in nkcc1b mRNA expression was observed in the brain of M. albus only after 6 days of terrestrial exposure, but both 1 day and 6 days of terrestrial exposure resulted in significant decreases in the protein abundance of Nkcc1b. These results are novel because it has been established in mammals that ammonia up-regulates NKCC1 expression in astrocytes and NKCC1 plays an important role in ammonia-induced astrocyte swelling and brain edema. By contrast, our results indicate for the first time that M. albus is able to down-regulate the mRNA and protein expression of nkcc1b/Nkcc1b in the brain when confronted with ammonia toxicity, which could be one of the contributing factors to its extraordinarily high brain ammonia tolerance. PMID:24069137

SODIUM-POTASSIUM-CHLORIDE COTRANSPORT IN THE REGULATION OF VASCULAR MYOGENIC TONE

Directory of Open Access Journals (Sweden)

S. N. Orlov

2014-01-01

Full Text Available The article discusses the data on the functioning of Na+,K+,2Cl– cotransport – the carrier providing electroneutral symport of sodium, potassium and chloride, as well as molecular mechanisms of the regulation and physiological significance of this carrier. We analyzed the novel data on involvement of ubiquitous isoform of Na+,K+,2Cl–cotransporter (NKCC1 in regulation of vascular smooth muscle contraction, and role of this carrier in the regulation of cell volume and intracellular chloride concentration.

Thermodynamic studies of (RbF + RbCl + H2O) and (CsF + CsCl + H2O) ternary systems from potentiometric measurements at T = 298.2 K

International Nuclear Information System (INIS)

Huang, Xiaoting; Li, Shu’ni; Zhai, Quanguo; Jiang, Yucheng; Hu, Mancheng

2016-01-01

Graphical abstract: Thermodynamic properties, such as mean activity coefficients, osmotic coefficients and excess Gibbs free energies, of the RbF + RbCl + H 2 O and CsF + CsCl + H 2 O ternary systems were determined from potentiometric measurement at 298.2 K. The Pitzer model and the Harned rule were used to fit the experimental data. - Highlights: • Thermodynamic properties of RbF + RbCl + H 2 O and CsF + CsCl + H 2 O ternary systems were determined. • The Pitzer model and the Harned rule were used to correlate the experimental data. • The mean activity coefficients, osmotic coefficients, and the excess Gibbs free energy were also obtained. - Abstract: Thermodynamic properties of (RbF + RbCl + H 2 O) and (CsF + CsCl + H 2 O) systems were determined by the potentiometric method for different ionic strength fractions y B of RbCl/CsCl at 298.2 K. The Pitzer model and the Harned rule were used to fit the experimental values. The Pitzer mixing parameters and the Harned coefficients were evaluated. In addition, the mean ionic activity coefficients of RbF/CsF and RbCl/CsCl, the osmotic coefficients, and the excess Gibbs energies of the systems studied were calculated.

Isolation, purification, and partial characterization of a membrane-bound Cl-/HCO3--activated ATPase complex from rat brain with sensitivity to GABAAergic ligands.

Science.gov (United States)

Menzikov, Sergey A

2017-02-07

This study describes the isolation and purification of a protein complex with [Formula: see text]-ATPase activity and sensitivity to GABA A ergic ligands from rat brain plasma membranes. The ATPase complex was enriched using size-exclusion, affinity, and ion-exchange chromatography. The fractions obtained at each purification step were subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE), which revealed four subunits with molecular mass ∼48, 52, 56, and 59 kDa; these were retained at all stages of the purification process. Autoradiography revealed that the ∼52 and 56 kDa subunits could bind [ 3 H]muscimol. The [Formula: see text]-ATPase activity of this enriched protein complex was regulated by GABA A ergic ligands but was not sensitive to blockers of the NKCC or KCC cotransporters.

IGF-1 and insulin exert opposite actions on ClC-K2 activity in the cortical collecting ducts.

Science.gov (United States)

Zaika, Oleg; Mamenko, Mykola; Boukelmoune, Nabila; Pochynyuk, Oleh

2015-01-01

Despite similar stimulatory actions on the epithelial sodium channel (ENaC)-mediated sodium reabsorption in the distal tubule, insulin promotes kaliuresis, whereas insulin-like growth factor-1 (IGF-1) causes a reduction in urinary potassium levels. The factors contributing to this phenomenon remain elusive. Electrogenic distal nephron ENaC-mediated Na(+) transport establishes driving force for Cl(-) reabsorption and K(+) secretion. Using patch-clamp electrophysiology, we document that a Cl(-) channel is highly abundant on the basolateral plasma membrane of intercalated cells in freshly isolated mouse cortical collecting duct (CCD) cells. The channel has characteristics attributable to the ClC-K2: slow gating kinetics, conductance ∼10 pS, voltage independence, Cl(-)>NO3 (-) anion selectivity, and inhibition/activation by low/high pH, respectively. IGF-1 (100 and 500 nM) acutely stimulates ClC-K2 activity in a reversible manner. Inhibition of PI3-kinase (PI3-K) with LY294002 (20 μM) abrogates activation of ClC-K2 by IGF-1. Interestingly, insulin (100 nM) reversibly decreases ClC-K2 activity in CCD cells. This inhibitory action is independent of PI3-K and is mediated by stimulation of a mitogen-activated protein kinase-dependent cascade. We propose that IGF-1, by stimulating ClC-K2 channels, promotes net Na(+) and Cl(-) reabsorption, thus reducing driving force for potassium secretion by the CCD. In contrast, inhibition of ClC-K2 by insulin favors coupling of Na(+) reabsorption with K(+) secretion at the apical membrane contributing to kaliuresis. Copyright © 2015 the American Physiological Society.

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

Directory of Open Access Journals (Sweden)

Santos Cavaiola T

2018-04-01

Full Text Available Tricia Santos Cavaiola, Jeremy Pettus Division of Endocrinology and Metabolism, University of California San Diego, San Diego, CA, USA Abstract: As the first cardiovascular (CV outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM, the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME® trial, which investigated the sodium glucose cotransporter 2 (SGLT2 inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL, which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM. Keywords: canagliflozin, cardiovascular outcomes, dapagliflozin, empagliflozin, mechanisms, sodium glucose cotransporter 2 inhibitors

The super sickling haemoglobin HbS-Oman: a study of red cell sickling, K+ permeability and associations with disease severity in patients heterozygous for HbA and HbS-Oman (HbA/S-Oman genotype).

Science.gov (United States)

Al Balushi, Halima W M; Wali, Yasser; Al Awadi, Maha; Al-Subhi, Taimoora; Rees, David C; Brewin, John N; Hannemann, Anke; Gibson, John S

2017-10-01

Studying different sickle cell genotypes may throw light on the pathogenesis of sickle cell disease (SCD). Here, the clinical profile, red cell sickling and K + permeability in 29 SCD patients (15 patients with severe disease and 14 with a milder form) of HbA/S-Oman genotype were analysed. The super sickling nature of this Hb variant was confirmed. The red cell membrane permeability to K + was markedly abnormal with elevated activities of P sickle , Gardos channel and KCl cotransporter (KCC). Results were consistent with Ca 2+ entry and Mg 2+ loss via P sickle stimulating Gardos channel and KCC activities. The abnormal red cell behaviour was similar to that in the commonest genotype of SCD, HbSS, in which the level of mutated Hb is considerably higher. Although activities of all three K + transporters also correlated with the level of HbS-Oman, there was no association between transport phenotype and disease severity. The super sickling behaviour of HbS-Oman may obviate the need for solute loss and red cell dehydration to encourage Hb polymerisation, required in other SCD genotypes. Disease severity was reduced by concurrent α thalassaemia, as observed in other SCD genotypes, and represents an obvious genetic marker for prognostic tests of severity in young SCD patients of the HbA/S-Oman genotype. © 2017 John Wiley & Sons Ltd.

Passive water and ion transport by cotransporters

DEFF Research Database (Denmark)

Loo, D D; Hirayama, B A; Meinild, A K

1999-01-01

the Lp of control oocytes. Passive Na+ transport (Na+ leak) was obtained from the blocker-sensitive Na+ currents in the absence of substrates (glucose and GABA). 2. Passive Na+ and water transport through SGLT1 were blocked by phlorizin with the same sensitivity (inhibitory constant (Ki), 3-5 micro......1. The rabbit Na+-glucose (SGLT1) and the human Na+-Cl--GABA (GAT1) cotransporters were expressed in Xenopus laevis oocytes, and passive Na+ and water transport were studied using electrical and optical techniques. Passive water permeabilities (Lp) of the cotransporters were determined from......M). When Na+ was replaced with Li+, phlorizin also inhibited Li+ and water transport, but with a lower affinity (Ki, 100 microM). When Na+ was replaced by choline, which is not transported, the SGLT1 Lp was indistinguishable from that in Na+ or Li+, but in this case water transport was less sensitive...

Protonic conduction of hydrogen impurities in K2OsCl6

International Nuclear Information System (INIS)

Willemsen, H.W.; Armstrong, R.L.; Meincke, P.P.M.

1979-01-01

Dielectric measurements as a function of temperature and frequency in single crystal K 2 OsCl 6 with defects containing protons are reported. The results are consistent with a model which assumes the defect state to be a simple interstitial proton which is hydrogen bonded to the nearest neighbor chlorine ions. Temperatures greater than 180 K shows that proton diffusion is thermally activated with a mobility of 10 -2 cm 2 /V-sec whereas below this temperature it is determined by quantum tunneling between localized states

Sodium-glucose co-transporter type 2 inhibitors reduce evening home blood pressure in type 2 diabetes with nephropathy.

Science.gov (United States)

Takenaka, Tsuneo; Kishimoto, Miyako; Ohta, Mari; Tomonaga, Osamu; Suzuki, Hiromichi

2017-05-01

The effects of sodium-glucose co-transporter type 2 inhibitors on home blood pressure were examined in type 2 diabetes with nephropathy. The patients with diabetic nephropathy were screened from medical records in our hospitals. Among them, 52 patients who measured home blood pressure and started to take sodium-glucose co-transporter type 2 inhibitors were selected. Clinical parameters including estimated glomerular filtration rate, albuminuria and home blood pressure for 6 months were analysed. Sodium-glucose co-transporter type 2 inhibitors (luseogliflozin 5 mg/day or canagliflozin 100 mg/day) reduced body weight, HbA1c, albuminuria, estimated glomerular filtration rate and office blood pressure. Although sodium-glucose co-transporter type 2 inhibitors did not alter morning blood pressure, it reduced evening systolic blood pressure. Regression analyses revealed that decreases in evening blood pressure predicted decrements in albuminuria. The present data suggest that sodium-glucose co-transporter type 2 inhibitors suppress sodium overload during daytime to reduce evening blood pressure and albuminuria.

An unexpected oxidation: NaK5Cl2(S2O62 revisited

Directory of Open Access Journals (Sweden)

William T. A. Harrison

2017-02-01

Full Text Available The title compound, NaK5Cl2(S2O62 [systematic name: sodium pentapotassium dichloride bis(dithionate], arose as an unexpected product from an organic synthesis that used dithionite (S2O42− ions as a reducing agent to destroy excess permanganate ions. Compared to the previous study [Stanley (1953. Acta Cryst. 6, 187–196], the present tetragonal structure exhibits a root 2a × root 2a × c super-cell due to subtle changes in the orientations of the dithionate anions. The structure can be visualized as a three-dimensional framework of [001] columns of alternating trans-NaO4Cl2 and KO4Cl2 octahedra cross-linked by the dithionate ions with the interstices occupied by KO6Cl2 polyhedra to generate a densely packed three-dimensional framework. The asymmetric unit comprises two sodium ions (site symmetries 4 and -4, four potassium ions (site symmetries = -4, 4, 1 and 1, three chloride ions (site symmetries = 4, 4 and 2 and two half-dithionate ions (all atoms on general positions. Both dithionate ions are completed by crystallographic inversion symmetry. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13:0.3702 (13 domain ratio.

Exploiting the interactions between the ruthenium Hoveyda–Grubbs catalyst and Al-modified mesoporous silica: the case of SBA15 vs. KCC-1

KAUST Repository

Werghi, Baraa; Pump, Eva; Tretiakov, Mykyta; Abou-Hamad, Edy; Gurinov, Andrei; Doggali, Pradeep; Anjum, Dalaver H.; Cavallo, Luigi; Bendjeriou-Sedjerari, Anissa; Basset, Jean-Marie

2018-01-01

Immobilization of the 2 generation Hoveyda-Grubbs catalyst HG-II onto well-ordered 2D hexagonal (SBA15) and 3D fibrous (KCC-1) mesostructured silica, which contained tetra-coordinated Al, has been investigated through the Surface Organometallic Chemistry (SOMC) methodology. The main interest of this study lies in the peculiarity of the silica supports, which display a well-defined tetrahedral aluminum hydride site displaying a strong Lewis acid character, [(Si-O-Si)(Si-O-)Al-H]. The resulting supported Hoveyda-Grubbs catalysts have been fully characterized by advanced solid state characterization techniques (FT-IR, H and C solid state NMR, DNP-SENS, EF-TEM...). Together with DFT calculations, the immobilization of HG-II does not occur through the formation of a covalent bond between the complex and the Al-modified mesoporous silica as expected, but through an Al⋯Cl-[Ru]-coordination. It is not surprising that in functionalized olefin metathesis of diethyldiallyl malonate, DEDAM (liquid phase), leaching of the catalyst is observed which is not the case in non-functionalized olefin metathesis of propene (gas phase). Besides, the results obtained in propene metathesis with HG-II immobilized either on SBA15 (d = 6 nm) or KCC-1 (d = 4 or 8 nm) highlight the importance of the accessibility of the catalytic site. Therefore, we demonstrate that KCC-1 is a promising and suitable 3D mesoporous support to overcome the diffusion of reactants into the porous network of heterogeneous catalysts.

Exploiting the interactions between the ruthenium Hoveyda–Grubbs catalyst and Al-modified mesoporous silica: the case of SBA15 vs. KCC-1

KAUST Repository

Werghi, Baraa

2018-03-05

Immobilization of the 2 generation Hoveyda-Grubbs catalyst HG-II onto well-ordered 2D hexagonal (SBA15) and 3D fibrous (KCC-1) mesostructured silica, which contained tetra-coordinated Al, has been investigated through the Surface Organometallic Chemistry (SOMC) methodology. The main interest of this study lies in the peculiarity of the silica supports, which display a well-defined tetrahedral aluminum hydride site displaying a strong Lewis acid character, [(Si-O-Si)(Si-O-)Al-H]. The resulting supported Hoveyda-Grubbs catalysts have been fully characterized by advanced solid state characterization techniques (FT-IR, H and C solid state NMR, DNP-SENS, EF-TEM...). Together with DFT calculations, the immobilization of HG-II does not occur through the formation of a covalent bond between the complex and the Al-modified mesoporous silica as expected, but through an Al⋯Cl-[Ru]-coordination. It is not surprising that in functionalized olefin metathesis of diethyldiallyl malonate, DEDAM (liquid phase), leaching of the catalyst is observed which is not the case in non-functionalized olefin metathesis of propene (gas phase). Besides, the results obtained in propene metathesis with HG-II immobilized either on SBA15 (d = 6 nm) or KCC-1 (d = 4 or 8 nm) highlight the importance of the accessibility of the catalytic site. Therefore, we demonstrate that KCC-1 is a promising and suitable 3D mesoporous support to overcome the diffusion of reactants into the porous network of heterogeneous catalysts.

High-surface-area silica nanospheres (KCC-1) with a fibrous morphology

KAUST Repository

Polshettiwar, Vivek; Cha, Dong Kyu; Zhang, Xixiang; Basset, Jean-Marie

2010-01-01

Fibrous nanosilica: A new family of high-surface-area silica nanospheres (KCC-1) have been prepared (see picture). KCC-1 features excellent physical properties, including high surface area, unprecedented fibrous surface morphology, high thermal (up to 950 °C) and hydrothermal stabilities, and high mechanical stability. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-surface-area silica nanospheres (KCC-1) with a fibrous morphology

KAUST Repository

Polshettiwar, Vivek

2010-08-02

Fibrous nanosilica: A new family of high-surface-area silica nanospheres (KCC-1) have been prepared (see picture). KCC-1 features excellent physical properties, including high surface area, unprecedented fibrous surface morphology, high thermal (up to 950 °C) and hydrothermal stabilities, and high mechanical stability. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quaternary reciprocal system Na,K//Cl,Co3,MoO4

International Nuclear Information System (INIS)

Kochkarov, Zh.A.; Gasanaliev, A.M.

2004-01-01

Quaternary reciprocal system Na,K//Cl,Co 3 ,MoO 4 has been investigated for the first time by differential thermal analysis using the methods of projective and differential geometry. A stable (KCl) 2 -Na 2 CO 3 -K 2 CO 3 -K 2 MoO 4 tetrahedron and (NaCl) 2 -(KCl) 2 -Na 2 CO 3 -K 2 MoO 4 -Na 2 MoO 4 pentatope have been revealed in the system. It has been found that four quadruple invariant points are realized in the Na,K//Cl,Co 3 ,MoO 4 system, including one eutectic and three peritectic points [ru

Ternary rare-earth halides of the A2MX5 type (A = K, In, NH4, Rb, Cs; X = Cl, Br, I)

International Nuclear Information System (INIS)

Meyer, G.; Soose, J.; Moritz, A.; Vitt, V.; Holljes, T.

1985-01-01

Ternary rare-earth (=M) chlorides, bromides, and iodides In 2 MCl 5 , (NH 4 ) 2 MCl 5 , Rb 2 MCl 5 , Cs 2 MCl 5 , CsRbMCl 5 , K 2 MBr 5 , Rb 2 MBr 5 , K 2 MI 5 , and Rb 2 MI 5 have been synthesized. Single crystals of In 2 PrCl 5 , Rb 2 PrCl 5 , K 2 PrBr 5 , and K 2 PrI 5 were grown and the structures refined. The other halides were characterized by X-ray powder patterns. They are isotypic either with K 2 PrCl 5 (orthorhombic, Pnma, Z = 4, hexagonal arrangement of chains of edge-connected polyhedra [PrX 7 ]) or with Cs 2 DyCl 5 (orthorhombic, Pbnm, Z = 4, hexagonal arrangement of cis-corner-connected octahedra [DyCl 6 ]) which may be discriminated in structure field diagrams. The thermal expansion was investigated for Cs 2 LuCl 5 and Rb 2 PrX 5 (X = Cl, Br, I). (author)

Molecular and neurochemical substrates of the audiogenic seizure strains: The GASH:Sal model.

Science.gov (United States)

Prieto-Martín, Ana I; Aroca-Aguilar, J Daniel; Sánchez-Sánchez, Francisco; Muñoz, Luis J; López, Dolores E; Escribano, Julio; de Cabo, Carlos

2017-06-01

Animal models of audiogenic epilepsy are useful tools to understand the mechanisms underlying human reflex epilepsies. There is accumulating evidence regarding behavioral, anatomical, electrophysiological, and genetic substrates of audiogenic seizure strains, but there are still aspects concerning their neurochemical basis that remain to be elucidated. Previous studies have shown the involved of γ-amino butyric acid (GABA) in audiogenic seizures. The aim of our research was to clarify the role of the GABAergic system in the generation of epileptic seizures in the genetic audiogenic seizure-prone hamster (GASH:Sal) strain. We studied the K + /Cl - cotransporter KCC2 and β2-GABAA-type receptor (GABAAR) and β3-GABAAR subunit expressions in the GASH:Sal both at rest and after repeated sound-induced seizures in different brain regions using the Western blot technique. We also sequenced the coding region for the KCC2 gene both in wild- type and GASH:Sal hamsters. Lower expression of KCC2 protein was found in GASH:Sal when compared with controls at rest in several brain areas: hippocampus, cortex, cerebellum, hypothalamus, pons-medulla, and mesencephalon. Repeated induction of seizures caused a decrease in KCC2 protein content in the inferior colliculus and hippocampus and an increase in the pons-medulla. When compared to controls, the basal β 2 -GABA A R subunit in the GASH:Sal was overexpressed in the inferior colliculus, rest of the mesencephalon, and cerebellum, whereas basal β 3 subunit levels were lower in the inferior colliculus and rest of the mesencephalon. Repeated seizures increased β2 both in the inferior colliculus and in the hypothalamus and β 3 in the hypothalamus. No differences in the KCC2 gene-coding region were found between GASH:Sal and wild-type hamsters. These data indicate that GABAergic system functioning is impaired in the GASH:Sal strain, and repeated seizures seem to aggravate this dysfunction. These results have potential clinical

Electrical conductivity of molten SnCl2 at temperature as high as 1314 K

International Nuclear Information System (INIS)

Salyulev, Alexander B.; Potapov, Alexei M.

2015-01-01

The electrical conductivity of molten SnCl 2 was measured in a wide temperature range (ΔT=763 K), from 551 K to temperature as high as 1314 K, that is, 391 above the boiling point of the salt. The specific electrical conductance was found to reach its maximum at 1143 K, after that it decreases with the temperature rising.

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

Science.gov (United States)

Cavaiola, Tricia Santos; Pettus, Jeremy

2018-01-01

As the first cardiovascular (CV) outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM), the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME®) trial, which investigated the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS) Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL), which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM. PMID:29695924

Study of thermoluminescence in K Cl crystals doped with Sr2+

International Nuclear Information System (INIS)

Russo, D.M.B.

1990-01-01

An attempt is made to correlate the F and Z 1 (F center modified by the presence of a two-valence impurity pair and and positive ion vacancy) and a V center, with the T L curve peaks observed in pure K Cl crystals doped with Sr 2+ , irradiated at room temperature. (L.C.J.A.)

Electrical conductivity of molten CdCl2 at temperatures as high as 1474 K

International Nuclear Information System (INIS)

Salyulev, Alexander B.; Potapov, Alexei M.

2016-01-01

The electrical conductivity of molten CdCl 2 was measured across a wide temperature range (ΔT=628 K), from 846 K to as high as 1474 K, i.e. 241 above the normal boiling point of the salt. In previous studies, a maximum temperature of 1201 K was reached, this being 273 lower than in the present work. The activation energy of electrical conductivity was calculated.

KCC1: First Nanoparticle developed by KAUST Catalysis Center

KAUST Repository

Basset, Jean-Marie

2010-08-01

KCC1 is the first Nanoparticle developed by KAUST Catalysis Center. Director of KAUST Catalysis Center, Dr. Jean-Marie Basset, Senior Research Scientist at KCC, Dr. Vivek Polshettiwar, and Dr. Dongkyu Cha of the Advanced Nanofabrication Imaging & Characterization Core Laboratory discuss the details of this recent discovery. This video was produced by KAUST Visualization Laboratory and KAUST Technology Transfer and Innovation - Terence McElwee, Director, Technology Transfer and Innovation - IP@kaust.edu.sa This technology is part of KAUST\\'s technology commercialization program that seeks to stimulate development and commercial use of KAUST-developed technologies. For more information email us at ip@kaust.edu.sa.

Kinetics and Products of the Reactions of Fluorine Atoms with ClNO and Br2 from 295 to 950 K.

Science.gov (United States)

Bedjanian, Yuri

2017-11-09

The kinetics and products of the reactions of F atoms with Br 2 and ClNO have been studied in a flow reactor coupled with an electron impact ionization mass spectrometer at nearly 2 Torr total pressure of helium and over a wide temperature range, T = 295-950 K. The rate constant of the reaction F + ClNO → products (1) was determined under pseudo-first order conditions, monitoring the kinetics of F atom consumption in excess of ClNO. The measured temperature independent rate constant, k 1 = (1.29 ± 0.13) × 10 -10 cm 3 molecule -1 s -1 (T = 299-950 K), was found to be in excellent agreement with the only previous low temperature study which allowed to recommend the value of k 1 in an extended temperature range, 228-950 K. FCl and Cl atoms were observed as the reactions products (corresponding to two reaction pathways: Cl-atom abstraction and replacement with fluorine atom, respectively) with the independent of temperature, in the range 295-948 K, yields of 0.68 ± 0.10 and 0.32 ± 0.05, respectively. Rate constant of the reaction F + Br 2 (2), k 2 = (1.28 ± 0.20) × 10 -10 cm 3 molecule -1 s -1 , determined using both absolute and relative rate methods, was found to be independent of temperature at T = 299-940 K.

Electrical conductivity of molten ZnCl2 at temperature as high as 1421 K

International Nuclear Information System (INIS)

Salyulev, Alexander B.; Potapov, Alexei M.

2015-01-01

The electrical conductivity of molten ZnCl 2 was measured in a wide temperature range (ΔT=863 K) to a temperature as high as 1421 K that is 417 degrees above the boiling point of the salt. At the temperature maximum of the own vapor pressure of the salt reached several megapascals.

Electrical conductivity of molten SnCl{sub 2} at temperature as high as 1314 K

Energy Technology Data Exchange (ETDEWEB)

Salyulev, Alexander B.; Potapov, Alexei M. [Ural Branch of RAS, Ekaterinburg (Russian Federation). Inst. of High-Temperature Electrochemistry

2015-07-01

The electrical conductivity of molten SnCl{sub 2} was measured in a wide temperature range (ΔT=763 K), from 551 K to temperature as high as 1314 K, that is, 391 above the boiling point of the salt. The specific electrical conductance was found to reach its maximum at 1143 K, after that it decreases with the temperature rising.

Isolation and characterization of antifungal compound from Lactobacillus plantarum KCC-10 from forage silage with potential beneficial properties.

Science.gov (United States)

Valan Arasu, M; Jung, M-W; Ilavenil, S; Jane, M; Kim, D-H; Lee, K-D; Park, H-S; Hur, T-Y; Choi, G-J; Lim, Y-C; Al-Dhabi, N A; Choi, K-C

2013-11-01

The purpose of this study was to isolate, identify and characterize an antifungal compound from Lactobacillus plantarum KCC-10 from forage silage with potential beneficial properties. The 16S rRNA gene-based phylogenetic affiliation was determined using bioinformatic tools and identified as Lactobacillus sp. KCC-10 with 100% sequence similarity to L. plantarum. The antifungal substances were extracted with ethyl acetate from spent medium in which Lactobacillus sp. KCC-10 was cultivated. Antifungal activity was assessed using the broth microdilution technique. The compounds were obtained by eluting the crude extract with various concentrations of solvents followed by chromatographic purification. Based on the infrared, (13) C nuclear magnetic resonance (NMR) and (1) H NMR spectral data, the compound was identified as a phenolic-related antibiotic. The minimum inhibitory concentration of the compound against Aspergillus clavatus, A. oryzae, Botrytis elliptica and Scytalidium vaccinii was 2.5 mg ml(-1) and that against A. fumigatus, A. niger and S. fusca was 5.0 mg ml(-1) , respectively. In addition, Lactobacillus sp. KCC-10 was highly sensitive towards oxgall (0.3%) but grew well in the presence of sodium taurocholate (0.3%). An antimicrobial susceptibility pattern was an intrinsic feature of this strain; thus, consumption does not represent a health risk to humans or animals. Novel L. plantarum KCC-10 with antifungal and potential probiotic properties was characterized for use in animal food. This study revealed that L. plantarum KCC-10 exhibited good antifungal activity similar to that of probiotic Lactobacillus strains. © 2013 The Society for Applied Microbiology.

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. © 2016 Pinelli et al.

An oil-in-water self-assembly synthesis, characterization and photocatalytic properties of nano Ag@AgCl surface-sensitized K2Ti4O9

International Nuclear Information System (INIS)

Liang, Yinghua; Lin, Shuanglong; Liu, Li; Hu, Jinshan; Cui, Wenquan

2014-01-01

Highlights: • The plasmatic Ag@AgCl surface-sensitized K 2 Ti 4 O 9 composite photocatalysts. • Ag@AgCl greatly increased visible light absorption for K 2 Ti 4 O 9 . • The photocatalysts exhibited enhanced photocatalytic dye degradation. - Abstract: Nano-sized plasmonic Ag@AgCl surface-sensitized K 2 Ti 4 O 9 composite photocatalysts (hereafter designated as Ag@AgCl/K 2 Ti 4 O 9 ) was synthesized via a facile oil-in-water self-assembly method. The photocatalytic activity of the prepared materials for RhB (Rhodamine B) degradation was examined under visible light irradiation. The results reveal that the size of Ag@AgCl, which evenly dispersed on the surface of K 2 Ti 4 O 9 , distributes about 20–50 nm. The UV–vis diffuse reflectance spectra indicate that Ag@AgCl/K 2 Ti 4 O 9 samples have a significantly enhanced optical absorption in 380–700 nm. The photocatalytic activities of the Ag@AgCl/K 2 Ti 4 O 9 samples increase first and then decrease with increasing amount of loading Ag@AgCl and the Ag@AgCl(20 wt.%)/K 2 Ti 4 O 9 sample exhibits the best photocatalytic activity and 94.47% RhB was degraded after irradiation for 2 h. Additionally, studies performed using radical scavengers indicated that O 2 · − and Cl 0 acted as the main reactive species. The electronic interaction was systematically studied and confirmed by the photo-electrochemical measurements

Refractive indices of K2ZnCl4 crystals in an incommensurate phase under uniaxial stresses

International Nuclear Information System (INIS)

Gaba, V.M.; Kogut, Z.O.; Brezvin, R.S.; Stadnik, V.I.

2010-01-01

The influence of uniaxial mechanical stresses directed along the principal crystallophysical axes on refractiveindex temperature dependences in K 2 ZnCl 4 crystals was studied. It is established that the refractive indices ni are quite sensitive to uniaxial stresses. Significant baric shifts of the paraphase-incommensurate-commensurate phase transition points to different temperature regions were observed, which is due to the effect of the uniaxial stress on the K 2 ZnCl 4 crystal structure. It is found that applying uniaxial pressure increases the value of the temperature hysteresis of the commensurate-incommensurate phase transition. (authors)

Electrical conductivity of molten CdCl{sub 2} at temperatures as high as 1474 K

Energy Technology Data Exchange (ETDEWEB)

Salyulev, Alexander B.; Potapov, Alexei M. [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of High-Temperature Electrochemistry

2016-11-01

The electrical conductivity of molten CdCl{sub 2} was measured across a wide temperature range (ΔT=628 K), from 846 K to as high as 1474 K, i.e. 241 above the normal boiling point of the salt. In previous studies, a maximum temperature of 1201 K was reached, this being 273 lower than in the present work. The activation energy of electrical conductivity was calculated.

Activity coefficients of CaCl{sub 2} in (serine or proline + water) mixtures at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Ma Jingjing [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Zhang Xinkuan [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); School of Chemistry and Chemical Engineering, Xinxiang University, Xinxiang, Henan 453003 (China); Zhuo Kelei, E-mail: lchow@mail.ucf.ed [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Liu Hongxun; Wang Jianji [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

2010-05-15

Activity coefficients for the (CaCl{sub 2} + amino acid + water) system were determined at a temperature of 298.15 K using ion-selective electrodes. The range of molalities of CaCl{sub 2} is (0.01 to 0.20) mol . kg{sup -1}, and that of amino acids is (0.10 to 0.40) mol . kg{sup -1}. The activity coefficients obtained from the Debye-Hueckel extended equation and the Pitzer equation are in good agreement with each other. Results show that the interactions between CaCl{sub 2} and amino acid are controlled mainly by the electrostatic interactions (attraction). Gibbs free energy interaction parameters (g{sub EA}) and salting constants (k{sub S}) are positive, indicating that these amino acids are salted out by CaCl{sub 2}. These results are discussed based on group additivity model.

Electrochemical and spectroscopie behaviour of iron in the molten NaCl-K2SO4 mixture

DEFF Research Database (Denmark)

Bjerrum, Niels; Petruchina, Irina; Volkov, S.V.

1996-01-01

The chemical and electrochemical dissolving of Armco iron in the NaCl-K2SO4 melt has been studied. In the case of the chemical dissolution, a sample becomes coated, as time goes on, with a dense film consisting of FeO, FeS and Fe3O4; precipitation in the melt is observed, the precipitate consisting...... not detect Fe(III) by electronic absorption spectra, possibly due to the superimposition of the charge transfer bands edge on low-intensity Fe(III) bands of the 5d electronic configuration. The solubility of Fe2O3 in the NaCl-K2SO4 melt is low and was determined to 2 x 10(-3) wt%....

Effect of oxygen on the complexing and electrochemical processes in the NaCl-KCl-K2TaF7 melt

International Nuclear Information System (INIS)

Polyakova, L.P.; Kononova, Z.A.; Kremenetskij, V.G.; Polyakov, E.K.

1997-01-01

Using the method of linear voltametry oxygen influence on electrochemical behaviour of tantalum during NaCl-KCl-K 2 TaF 7 melt titration with sodium oxide is studied. It is shown that in NaCl-KCl-K 3 TaOF 6 and NaCl-KCl-K 2 TaF 7 -Na 2 O melts (at molar ratio O/Ta = 1 ) tantalum reduction proceeds from oxyhalide complex of TaOClF 5 -3 composition. On further titration with sodium oxide (1 5 3- complexes, but their concentration is decreased at the cost of formation of insoluble compound K 0,4 TaO 2,4 F 0,6 . When O/Ta ≥ 2,4 tantalum concentration in electrolyte is decreased up to zero and peak of tantalum reduction on voltamogram is not recorded. (author)

Nitridated fibrous silica (KCC-1) as a sustainable solid base nanocatalyst

KAUST Repository

Bouhrara, Mohamed; Ranga, Chanakya; Fihri, Aziz; Shaikh, Rafik; Sarawade, Pradip; Emwas, Abdul-Hamid M.; Hedhili, Mohamed N.; Polshettiwar, Vivek

2013-01-01

We observed that support morphology has dramatic effects on the performance of nitridated silica as a base. By simply replacing conventional silica supports (such as SBA-15 and MCM-41) with fibrous nanosilica (KCC-1), we observed multifold enhancement in the catalytic activity of the nitridated solid base for Knoevenagel condensations and transesterification reactions. This enhancement of the activity can be explained by amine accessibility, which is excellent in KCC-1 due to its open and flexible fibrous structure, that facilitates penetration and interaction with basic amine sites. © 2013 American Chemical Society.

Nitridated fibrous silica (KCC-1) as a sustainable solid base nanocatalyst

KAUST Repository

Bouhrara, Mohamed

2013-09-03

We observed that support morphology has dramatic effects on the performance of nitridated silica as a base. By simply replacing conventional silica supports (such as SBA-15 and MCM-41) with fibrous nanosilica (KCC-1), we observed multifold enhancement in the catalytic activity of the nitridated solid base for Knoevenagel condensations and transesterification reactions. This enhancement of the activity can be explained by amine accessibility, which is excellent in KCC-1 due to its open and flexible fibrous structure, that facilitates penetration and interaction with basic amine sites. © 2013 American Chemical Society.

Heat capacity of Sr10(PO4)6Cl2 and Ca10(PO4)6Cl2 by DSC

International Nuclear Information System (INIS)

Venkata Krishnan, R.; Jena, Hrudananda; Govindan Kutty, K.V.; Nagarajan, K.

2008-01-01

Strontium and calcium chloroapatites were synthesized by wet chemical method, characterized by X-ray diffraction and are found to be phase pure materials. The measured room temperature lattice parameter of Ca 10 (PO 4 ) 6 Cl 2 is a = 9.523 A, c = 6.855 A and for Sr 10 (PO 4 ) 6 Cl 2 is a = 9.876 A, c = 7.188 A. Heat capacity measurements were carried out on Ca 10 (PO 4 ) 6 Cl 2 and Sr 10 (PO 4 ) 6 Cl 2 by DSC in the temperature range 298-800 K. The heat capacity values of Sr 10 (PO 4 ) 6 Cl 2 is higher at all temperatures than Ca 10 (PO 4 ) 6 Cl 2 . Enthalpy and entropy increments were computed. Heat capacity values of Ca 10 (PO 4 ) 6 Cl 2 and Sr 10 (PO 4 ) 6 Cl 2 at 298 K are 758 and 868 J K -1 mol -1 , respectively

Thermodynamics properties of plutonium in NaCl-KCl and CaCl2 at 1073 K and in liquid gallium

International Nuclear Information System (INIS)

Lambertin, D.; Ched'homme, S.; Bourges, G.; Pescayre, L.; Sanchez, S.; Picard, G.

2004-01-01

Cadmium and bismuth metal are mostly used as solvent in nuclear pyrochemical processes and especially in actinides/lanthanides separations. Gallium metal has been chosen because no literature values are available with plutonium and its regeneration by refining at low temperature is possible. Electrochemical window of gallium metal and activity coefficient of plutonium in gallium have been determined by using potentiometric method. Secondly, the electrochemical properties of plutonium have been studied in molten equimolar NaCl/KCl and CaCl 2 at 1073 K by cyclic voltammetry. The standard potentials of Pu(III)/Pu redox couple, respectively, -2,54 V and -2,51 V, led to the calculation of the activity coefficients of Pu(III). In CaCl 2 the complexation of Pu(III) ions is lower and the voltage gap between Pu(III)/Pu couple and the solvent limit is higher. The new data on plutonium electrochemistry in molten chlorides and liquid gallium media combined with literature data on lanthanides suggest that gallium can be a good solvent metal for pyro-chemistry separation. (authors)

Electrochemical characterisation of CaCl2 deficient LiCl-KCl-CaCl2 eutectic melt and electro-deoxidation of solid UO2

Science.gov (United States)

Sri Maha Vishnu, D.; Sanil, N.; Mohandas, K. S.; Nagarajan, K.

2016-03-01

The CaCl2 deficient ternary eutectic melt LiCl-KCl-CaCl2 (50.5: 44.2: 5.3 mol %) was electrochemically characterised by cyclic voltammetry and polarization techniques in the context of its probable use as the electrolyte in the electrochemical reduction of solid UO2 to uranium metal. Tungsten (cathodic polarization) and graphite (anodic polarization) working electrodes were used in these studies carried out in the temperature range 623 K-923 K. The cathodic limit of the melt was observed to be set by the deposition of Ca2+ ions followed by Li+ ions on the tungsten electrode and the anodic limit by oxidation of chloride ions on the graphite electrode (chlorine evolution). The difference between the onset potential of deposition of Ca2+ and Li+ was found to be 0.241 V at a scan rate of 20 mV/s at 623 K and the difference decreased with increase in temperature and vanished at 923 K. Polarization measurements with stainless steel (SS) cathode and graphite anode at 673 K showed the possibility of low-energy reactions occurring on the UO2 electrode in the melt. UO2 pellets were cathodically polarized at 3.9 V for 25 h to test the feasibility of electro-reduction to uranium in the melt. The surface of the pellets was found reduced to U metal.

Positioning of sodium-glucose cotransporter-2 inhibitors in national and international guidelines.

Science.gov (United States)

Morillas, Carlos

2016-11-01

Sodium-glucose cotransporter-2 inhibitors (SGLT2-i) selectively and reversibly inhibit sodium-glucose cotransporter-2 (SGLT2), promoting renal glucose excretion and reducing plasma glycaemia. By increasing renal glucose excretion, these drugs favour a negative energy balance, leading to weight loss. Their glucoselowering effect is independent of insulin. Although these drugs have only recently been developed, they have been included in all the main national and international guidelines since 2014. The present review summarises the most important recommendations on the use of SGLT2 in patients with DM2 contained in the most recently published guidelines and consensus statements. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Reactions of POxCly- ions with O2(a 1[Delta]g), H2O, and Cl2 at 298 K

Science.gov (United States)

Midey, Anthony J.; Dotan, Itzhak; Viggiano, A. A.

2008-06-01

The rate constants and product branching ratios for the reactions of phosphorus oxychloride anions, POxCly- for x = 1-2 and y = 1-3, with O2(a 1[Delta]g), Cl2, and H2O have been measured in a selected ion flow tube (SIFT) at 298 K. A mixture of O2(a 1[Delta]g) in O2 has been produced using a recently designed chemical singlet oxygen generator (sparger) with an emission detection scheme adopted previously in our laboratory. The experiments continue a series of investigations into the oxidation reactions of POxCly- ions, searching for pathways to the terminal PO2- and PO3- ions observed in combustion chemistry with POCl3 present. None of the POxCly- ions react with H2O or O2(a 1[Delta]g). The O2(a 1[Delta]g) rate constants have a limit of <1 × 10-11 cm3 s-1, except for PO2Cl- where a limit of <5 × 10-11 cm3 s-1 has been determined. The H2O rate constants have limits of <1 × 10-11 cm3 s-1. All of the POxCly- ions react with Cl2, excluding PO3- and PO2Cl2-. Depending on the reactant ion, Cl-, Cl2- or PO2Cl2- product ions form.

Effects of 5-hydroxymethyl-2-furfural on the volume and membrane permeability of red blood cells from patients with sickle cell disease

Science.gov (United States)

Hannemann, Anke; Cytlak, Urszula M; Rees, David C; Tewari, Sanjay; Gibson, John S

2014-01-01

The heterocyclic aldehyde 5-hydroxymethyl-2-furfural (5HMF) interacts allosterically with the abnormal form of haemoglobin (Hb), HbS, in red blood cells (RBCs) from patients with sickle cell disease (SCD), thereby increasing oxygen affinity and decreasing HbS polymerization and RBC sickling during hypoxia. We hypothesized that should 5HMF also inhibit the main cation pathways implicated in the dehydration of RBCs from SCD patients – the deoxygenation-induced cation pathway (Psickle), the Ca2+-activated K+ channel (the Gardos channel) and the K+–Cl− cotransporter (KCC) – it would have a synergistic effect in protection against sickling, directly through interacting with HbS, and indirectly through maintaining hydration and reducing [HbS]. This study was therefore designed to investigate the effects of 5HMF on RBC volume and K+ permeability in vitro. 5HMF markedly reduced the deoxygenation-induced dehydration of RBCs whether in response to maintained deoxygenation or to cyclical deoxygenation/re-oxygenation. 5HMF was found to inhibit Psickle, an effect which correlated with its effects on sickling. Deoxygenation-induced activation of the Gardos channel and exposure of phosphatidylserine were also inhibited, probably indirectly via reduced entry of Ca2+ through the Psickle pathway. Effects of 5HMF on KCC were more modest with a slight inhibition in N-ethylmaleimide (NEM, 1 mm)-treated RBCs and stimulation in RBCs untreated with NEM. These findings support the hypothesis that 5HMF may also be beneficial through effects on RBC ion and water homeostasis. PMID:25015917

Electrical conductivity of molten ZnCl{sub 2} at temperature as high as 1421 K

Energy Technology Data Exchange (ETDEWEB)

Salyulev, Alexander B.; Potapov, Alexei M. [RAS Ural Branch, Ekaterinburg. (Russian Federation) Institute of High-Temperature Electrochemistry

2015-07-01

The electrical conductivity of molten ZnCl{sub 2} was measured in a wide temperature range (ΔT=863 K) to a temperature as high as 1421 K that is 417 degrees above the boiling point of the salt. At the temperature maximum of the own vapor pressure of the salt reached several megapascals.

Vapor pressures and isopiestic molalities of concentrated CaCl2(aq), CaBr2(aq), and NaCl(aq) to T = 523 K

International Nuclear Information System (INIS)

Gruszkiewicz, Miroslaw S.; Simonson, John M.

2005-01-01

The Oak Ridge National Laboratory high-temperature isopiestic apparatus was outfitted with precise pressure gauges to allow for direct vapor pressure measurements. Vapor pressures over concentrated solutions of CaCl 2 (aq), and CaBr 2 (aq) were measured at temperatures between (380.15 and 523.15) K in the range of water activities between 0.2 and 0.85. Isopiestic molalities were used to determine osmotic coefficients at the conditions where NaCl reference standard solutions remained undersaturated. The main goal of this work was to improve the accuracy of isopiestic comparisons based on the calcium chloride reference standard. Osmotic coefficients for CaCl 2 (aq) and CaBr 2 (aq) calculated from both isopiestic and direct vapor pressure results were combined with the literature data and used to build general thermodynamic models based on a variant of extended Pitzer ion-interaction equations and valid at the saturation pressure of water. While these empirical models approach the accuracy of the experimental data in a wider range of concentrations and temperatures than any previously published equations, considerable amounts of accurate data and a substantial effort are required in order to obtain a satisfactory representation using power series-based virial equations. The effect of experimental uncertainties on the accuracy of the direct vapor pressure results is discussed, including in particular the error caused by the presence in the apparatus of a small amount of CO 2 . The substantial decrease of the solubility product of CaCO 3 in concentrated chloride solutions at temperatures above 423 K is a serious defect of calcium chloride as a water activity reference standard

New saliva secretion model based on the expression of Na+-K+ pump and K+ channels in the apical membrane of parotid acinar cells.

Science.gov (United States)

Almássy, János; Siguenza, Elias; Skaliczki, Marianna; Matesz, Klara; Sneyd, James; Yule, David I; Nánási, Péter P

2018-04-01

The plasma membrane of parotid acinar cells is functionally divided into apical and basolateral regions. According to the current model, fluid secretion is driven by transepithelial ion gradient, which facilitates water movement by osmosis into the acinar lumen from the interstitium. The osmotic gradient is created by the apical Cl - efflux and the subsequent paracellular Na + transport. In this model, the Na + -K + pump is located exclusively in the basolateral membrane and has essential role in salivary secretion, since the driving force for Cl - transport via basolateral Na + -K + -2Cl - cotransport is generated by the Na + -K + pump. In addition, the continuous electrochemical gradient for Cl - flow during acinar cell stimulation is maintained by the basolateral K + efflux. However, using a combination of single-cell electrophysiology and Ca 2+ -imaging, we demonstrate that photolysis of Ca 2+ close to the apical membrane of parotid acinar cells triggered significant K + current, indicating that a substantial amount of K + is secreted into the lumen during stimulation. Nevertheless, the K + content of the primary saliva is relatively low, suggesting that K + might be reabsorbed through the apical membrane. Therefore, we investigated the localization of Na + -K + pumps in acinar cells. We show that the pumps appear evenly distributed throughout the whole plasma membrane, including the apical pole of the cell. Based on these results, a new mathematical model of salivary fluid secretion is presented, where the pump reabsorbs K + from and secretes Na + to the lumen, which can partially supplement the paracellular Na + pathway.

Gold Nanoparticles Supported on Fibrous Silica Nanospheres (KCC-1) as Efficient Heterogeneous Catalysts for CO Oxidation

KAUST Repository

Qureshi, Ziyauddin S.; Sarawade, Pradip B.; Hussain, Irshad; Zhu, Haibo; Al-Johani, Hind; Anjum, Dalaver H.; Hedhili, Mohamed N.; Maity, Niladri; D'Elia, Valerio; Basset, Jean-Marie

2016-01-01

Gold nanoparticles (Au NPs) of different sizes were supported on fibrous silica nanospheres (KCC-1) by various methods. The size and the location of the Au NPs on the support were found to depend on the preparation method. The KCC-1-supported Au NPs were thoroughly characterized by using HR-TEM, XRD, X-ray photoelectron spectroscopy, UV, and Brunauer-Emmett-Teller surface area measurements and were applied in catalysis for the oxidation of CO. The catalytic performance is discussed in relation to the morphological properties of KCC-1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gold Nanoparticles Supported on Fibrous Silica Nanospheres (KCC-1) as Efficient Heterogeneous Catalysts for CO Oxidation

KAUST Repository

Qureshi, Ziyauddin S.

2016-04-13

Gold nanoparticles (Au NPs) of different sizes were supported on fibrous silica nanospheres (KCC-1) by various methods. The size and the location of the Au NPs on the support were found to depend on the preparation method. The KCC-1-supported Au NPs were thoroughly characterized by using HR-TEM, XRD, X-ray photoelectron spectroscopy, UV, and Brunauer-Emmett-Teller surface area measurements and were applied in catalysis for the oxidation of CO. The catalytic performance is discussed in relation to the morphological properties of KCC-1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Localization and functional characterization of the human NKCC2 isoforms

DEFF Research Database (Denmark)

Carota, I; Theilig, F; Oppermann, M

2010-01-01

AIM: Salt reabsorption across the apical membrane of cells in the thick ascending limb (TAL) of Henle is primarily mediated by the bumetanide-sensitive Na(+)/K(+)/2Cl(-) cotransporter NKCC2. Three full-length splice variants of NKCC2 (NKCC2B, NKCC2A and NKCC2F) have been described. The NKCC2 isof...

Physiology and pathophysiology of ClC-K/barttin channels.

Science.gov (United States)

Fahlke, Christoph; Fischer, Martin

2010-01-01

ClC-K channels form a subgroup of anion channels within the ClC family of anion transport proteins. They are expressed predominantly in the kidney and in the inner ear, and are necessary for NaCl resorption in the loop of Henle and for K+ secretion by the stria vascularis. Subcellular distribution as well as the function of these channels are tightly regulated by an accessory subunit, barttin. Barttin improves the stability of ClC-K channel protein, stimulates the exit from the endoplasmic reticulum and insertion into the plasma membrane and changes its function by modifying voltage-dependent gating processes. The importance of ClC-K/barttin channels is highlighted by several genetic diseases. Dysfunctions of ClC-K channels result in Bartter syndrome, an inherited human condition characterized by impaired urinary concentration. Mutations in the gene encoding barttin, BSND, affect the urinary concentration as well as the sensory function of the inner ear. Surprisingly, there is one BSND mutation that causes deafness without affecting renal function, indicating that kidney function tolerates a reduction of anion channel activity that is not sufficient to support normal signal transduction in inner hair cells. This review summarizes recent work on molecular mechanisms, physiology, and pathophysiology of ClC-K/barttin channels.

Physiology and pathophysiology of ClC-K/barttin channels

Directory of Open Access Journals (Sweden)

Christoph eFahlke

2010-11-01

Full Text Available ClC-K channels form a subgroup of anion channels within the ClC family of anion transport proteins. They are expressed predominantly in the kidney and in the inner ear, and are necessary for NaCl resorption in the loop of Henle and for K+ secretion by the stria vascularis. Subcellular distribution as well as the function of these channels are tightly regulated by an accessory subunit, barttin. Barttin improves the stability of ClC-K channel protein, stimulates the exit from the endoplasmic reticulum and insertion into the plasma membrane and changes its function by modifying voltage-dependent gating processes. The importance of ClC-K/barttin channels is highlighted by several genetic diseases. Dysfunctions of ClC-K channels result in Bartter syndrome, an inherited human condition characterized by impaired urinary concentration. Mutations in the gene encoding barttin, BSND, affect the urinary concentration as well as the sensory function of the inner ear. Surprisingly, there is one BSND mutation that causes deafness without affecting renal function, indicating that kidney function tolerates a reduction of anion channel activity that is not sufficient to support normal signal transduction in inner hair cells. This review summarizes recent work on molecular mechanisms, physiology and pathophysiology of ClC-K/barttin channels.

Control of Cl- transport in the operculum epithelium of Fundulus heteroclitus: long- and short-term salinity adaptation

DEFF Research Database (Denmark)

Hoffmann, E K; Hoffmann, E; Lang, F

2002-01-01

kinase A (PKA) inhibitors H-89 and KT 5720 had no effect after mannitol addition whereas isoproterenol stimulation was completely blocked by H-89. This indicates that PKA is involved in the activation of the apical Cl(-) channel via c-AMP whereas the shrinkage activation of the Na(+), K(+), 2Cl......(-) cotransporter is independent of PKA activation. The steady-state Cl(-) secretion was stimulated by an inhibitor of serine/threonine phosphatases of the PP-1 and PP-2A type and inhibited by a PKC inhibitor but not by a PKA inhibitor. Thus, it seems to be determined by continuous phosphorylation...... and dephosphorylation involving PKC but not PKA. The steady-state Cl(-) secretion and the maximal obtainable Cl(-) secretion were measured in freshwater-adapted fish and in fish retransferred to saltwater. No I(SC) could be measured in freshwater-adapted fish or in the fish within the first 18 h after transfer...

Thermodynamics properties of plutonium in NaCl-KCl and CaCl{sub 2} at 1073 K and in liquid gallium

Energy Technology Data Exchange (ETDEWEB)

Lambertin, D.; Ched' homme, S.; Bourges, G.; Pescayre, L.; Sanchez, S.; Picard, G

2004-07-01

Cadmium and bismuth metal are mostly used as solvent in nuclear pyrochemical processes and especially in actinides/lanthanides separations. Gallium metal has been chosen because no literature values are available with plutonium and its regeneration by refining at low temperature is possible. Electrochemical window of gallium metal and activity coefficient of plutonium in gallium have been determined by using potentiometric method. Secondly, the electrochemical properties of plutonium have been studied in molten equimolar NaCl/KCl and CaCl{sub 2} at 1073 K by cyclic voltammetry. The standard potentials of Pu(III)/Pu redox couple, respectively, -2,54 V and -2,51 V, led to the calculation of the activity coefficients of Pu(III). In CaCl{sub 2} the complexation of Pu(III) ions is lower and the voltage gap between Pu(III)/Pu couple and the solvent limit is higher. The new data on plutonium electrochemistry in molten chlorides and liquid gallium media combined with literature data on lanthanides suggest that gallium can be a good solvent metal for pyro-chemistry separation. (authors)

Low-temperature heat capacities and thermodynamic properties of ethylenediammonium tetrachlorozincate chloride (C2H10N2)2(ZnCl4)Cl2

International Nuclear Information System (INIS)

He, Dong-Hua; Di, You-Ying; Wang, Bin; Dan, Wen-Yan; Tan, Zhi-Cheng

2010-01-01

The ethylenediammonium tetrachlorozincate chloride (C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the compound were measured by a precision automatic adiabatic calorimeter over the temperature range from T = 77-377 K. A polynomial equation of heat capacities as a function of the reduced temperature was fitted by a least square method. Based on the polynomial equation, the smoothed heat capacities and thermodynamic functions of the title compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K. A thermochemical cycle was designed and the enthalpy change of the solid phase reaction of ethylenediamine dihydrochloride with zinc chloride was determined to be Δ r H m o =-(17.9±0.6)kJmol -1 by an isoperibol solution-reaction calorimeter. Finally, the standard molar enthalpy of formation of the title compound was derived to be Δ f H m o [(C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 ,s]=-(1514.4±2.7)kJmol -1 in accordance with Hess law.

Thermodynamic Study of Solid-Liquid Equilibrium in NaCl-NaBr-H2O System at 288.15 K

Science.gov (United States)

Li, Dan; Meng, Ling-zong; Deng, Tian-long; Guo, Ya-fei; Fu, Qing-Tao

2018-06-01

The solubility data, composition of the solid solution and refractive indices of the NaCl-NaBr-H2O system at 288.15 K were studied with the isothermal equilibrium dissolution method. The solubility diagram and refractive index diagram of this system were plotted at 288.15 K. The solubility diagram consists of two crystallization zones for solid solution Na(Cl,Br) · 2H2O and Na(Cl,Br), one invariant points cosaturated with two solid solution and two univariant solubility isothermal curves. On the basis of Pitzer and Harvie-Weare (HW) chemical models, the composition equations and solubility equilibrium constant equations of the solid solutions at 288.15 K were acquired using the solubility data, the composition of solid solutions, and binary Pitzer parameters. The solubilities calculated using the new method combining the equations are in good agreement with the experimental data.

Apparent molar volumes for dilute solutions of NaClO4 and [Co(en) 3](ClO4)3 in D2O and H2O at 278-318 K

International Nuclear Information System (INIS)

Bottomley, G.A.; Glossop, L.G.

1981-01-01

Apparent molar volumes for dilute solutions of NaClO 4 and [Co(en) 3 ](ClO 4 ) 3 in D 2 O and H 2 O were measured by using a dilatometry technique at 278, 298 and 318K. Comparison of limiting slopes with the Debye-Huckel predictions from the dielectric constant and compressibility of H 2 O and D 2 O is complicated by ion pairing. The apparent molar volumes for NaClO 4 were less in D 2 O than in H 2 O. The complex [Co(en) 3 ](ClO 4 ) 3 when studied in D 2 O had its amine protons exchanged by deuterium; this did not allow a direct comparison of the apparent molar volumes of the protonated complex in each solvent system, but revealed a large isotope effect. The apparent molar volumes of the [Co(en) 3 ](ClO 4 ) 3 showed a much larger temperature dependence than that of NaClO 4

In-vitro assessment of the probiotic potential of Lactobacillus plantarum KCC-24 isolated from Italian rye-grass (Lolium multiflorum) forage.

Science.gov (United States)

Vijayakumar, Mayakrishnan; Ilavenil, Soundharrajan; Kim, Da Hye; Arasu, Mariadhas Valan; Priya, Kannappan; Choi, Ki Choon

2015-04-01

The aim of the present study was to determine the probiotic potential of the lactic acid bacteria Lactobacillus plantarum KCC-24 (L. plantarum KCC-24), that was isolated and characterized from Italian ryegrass (Lolium multiflorum) forage. The following experiments were performed to assess the probiotic characteristics such as antifungal activity, antibiotic susceptibility, resistance to low pH, stimulated gastric juice and bile salts, proteolytic activity, auto-aggregation, cell surface hydrophobicity, and in vitro antioxidant property. The isolated L. plantarum KCC-24 exhibited significant antifungal activity against the various fungal strains of Aspergillus fumigatus (73.43%), Penicillium chrysogenum (59.04%), Penicillium roqueforti (56.67%), Botrytis elliptica (40.23%), Fusarium oxysporum (52.47%) and it was susceptible to numerous antibiotics, survived in low pH, was resistant to stimulated gastric juices and bile salts (0.3% w/v). Moreover, L. plantarum KCC-24 exhibited good proteolytic activity. In addition L. plantarum KCC-24 showed potent antioxidant and hydrogen peroxide resistant property. In conclusion, the isolated L. plantarum KCC-24 exhibited several characteristics to prove it's excellent as a potential probiotic candidate for developing quality food for ruminant animals and human. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cotransport of H+, lactate, and H2O in porcine retinal pigment epithelial cells

DEFF Research Database (Denmark)

Hamann, Steffen; Kiilgaard, Jens Folke; la Cour, Morten

2003-01-01

) for the H(+) and lactate fluxes. The data suggest that H(2)O is cotransported along with H(+) and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue...... and supports our previous study performed by an invasive technique in an amphibian tissue....

Intermolecular C-H···O, Cl···Cl and π-π interactions in the 2-dichloromethyl derivative of vitamin K3.

Science.gov (United States)

Soave, Raffaella; Colombo, Pietro

2013-12-15

The title 1,4-naphthoquinone, 2-dichloromethyl-3-methyl-1,4-dihydronaphthalene-1,4-dione, C12H8Cl2O2, is a chlorinated derivative of vitamin K3, which is a synthetic compound also known as menadione. Molecules of (I) are planar and lie on a crystallographic mirror plane (Z' = 0.5) in the space group Pnma. They are connected to each other by C-H···O hydrogen bonds, forming two-dimensional layers parallel to the ac plane. In addition, Cl···Cl and π-π interactions link adjacent molecules in different layers, thus forming zigzag ribbons along the b axis, such that a three-dimensional architecture is generated.

Water-transporting proteins

DEFF Research Database (Denmark)

Zeuthen, Thomas

2010-01-01

. In the K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water...... transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support...... to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity...

Reversed electrogenic sodium bicarbonate cotransporter 1 is the major acid loader during recovery from cytosolic alkalosis in mouse cortical astrocytes.

Science.gov (United States)

Theparambil, Shefeeq M; Naoshin, Zinnia; Thyssen, Anne; Deitmer, Joachim W

2015-08-15

The regulation of H(+) i from cytosolic alkalosis has generally been attributed to the activity of Cl(-) -coupled acid loaders/base extruders in most cell types, including brain cells. The present study demonstrates that outwardly-directed sodium bicarbonate cotransport via electrogenic sodium bicarbonate cotransporter 1 (NBCe1) mediates the major fraction of H(+) i regulation from cytosolic alkalosis in mouse cortical astrocytes. Cl(-) -coupled acid-loading transporters play only a minor role in the regulation of H(+) i from alkalosis in mouse cortical astrocytes. NBCe1-mediated H(+) i regulation from alkalosis was dominant, with the support of intracellular carbonic anhydrase II, even when the intra- and extracellular [HCO3 (-) ] was very low (sodium bicarbonate cotransporter 1 (NBCe1) and for carbonic anhydrase (CA) isoform II. An acute cytosolic alkalosis was induced by the removal of either CO2 /HCO3 (-) or butyric acid, and the subsequent acid loading was analysed by monitoring changes in cytosolic H(+) or Na(+) using ion-sensitive fluorescent dyes. We have identified that NBCe1 reverses during alkalosis and contributes more than 70% to the rate of recovery from alkalosis by extruding Na(+) and HCO3 (-) . After CA inhibition or in CAII-knockout (KO) cells, the rate of recovery was reduced by 40%, and even by 70% in the nominal absence of CO2 /HCO3 (-) . Increasing the extracellular K(+) concentration modulated the rate of acid loading in wild-type cells, but not in NBCe1-KO cells. Removing chloride had only a minor effect on the recovery from alkalosis. Reversal of NBCe1 by reducing pH/[HCO3 (-) ] was demonstrated in astrocytes and in Xenopus oocytes, in which human NBCe1 was heterologously expressed. The results obtained suggest that reversed NBCe1, supported by CAII activity, plays a major role in acid-loading cortical astrocytes to support recovery from cytosolic alkalosis. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Partial molar volumes and viscosities of aqueous hippuric acid solutions containing LiCl and MnCl2 · 4H2O at 303.15 K

Science.gov (United States)

Deosarkar, S. D.; Tawde, P. D.; Zinjade, A. B.; Shaikh, A. I.

2015-09-01

Density (ρ) and viscosity (η) of aqueous hippuric acid (HA) solutions containing LiCl and MnCl2 · 4H2O have been studied at 303.15 K in order to understand volumetric and viscometric behavior of these systems. Apparent molar volume (φv) of salts were calculated from density data and fitted to Massons relation and partial molar volumes (φ{v/0}) at infinite dilution were determined. Relative viscosity data has been used to determine viscosity A and B coefficients using Jones-Dole relation. Partial molar volume and viscosity coefficients have been discussed in terms of ion-solvent interactions and overall structural fittings in solution.

Vasopressin induces phosphorylation of the thiazide-sensitive sodium chloride cotransporter in the distal convoluted tubule

DEFF Research Database (Denmark)

Pedersen, Nis Borbye; Hofmeister, Marlene Vind; Rosenbaek, Lena L

2010-01-01

The thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is important for renal electrolyte balance and its phosphorylation causes an increase in its transport activity and cellular localization. Here, we generated phospho-specific antibodies against two conserved N-terminal phosphorylation sites...

The Cathodic Behavior of Ti(III) Ion in a NaCl-2CsCl Melt

Science.gov (United States)

Song, Yang; Jiao, Shuqiang; Hu, Liwen; Guo, Zhancheng

2016-02-01

The cathodic behavior of Ti(III) ions in a NaCl-2CsCl melt was investigated by cyclic voltammetry, chronopotentiometry, and square wave voltammetry with a tungsten electrode being the working electrode at different temperatures. The results show that the cathodic behavior of Ti(III) ion consists of two irreversible steps: Ti3+ + e = Ti2+ and Ti2+ + 2 e = Ti. The diffusion coefficient for the Ti(III) ion in the NaCl-2CsCl eutectic is 1.26 × 10-5 cm2 s-1 at 873 K (600 °C), increases to be 5.57 × 10-5 cm2 s-1 at 948K (675°C), and further rises to 10.8 × 10-5 cm2 s-1 at 1023 (750 °C). Moreover, galvanostatic electrolysis performed on a titanium electrode further presents the feasibility of electrodepositing metallic titanium in the molten NaCl-2CsCl-TiCl3 system.

Vapor pressures and isopiestic molalities of concentrated CaCl{sub 2}(aq), CaBr{sub 2}(aq), and NaCl(aq) to T = 523 K

Energy Technology Data Exchange (ETDEWEB)

Gruszkiewicz, Miroslaw S. [Oak Ridge National Laboratory, Chemical Sciences Division, P.O. Box 2008, Building 4500S MS-6110, Oak Ridge, TN 37831-6110 (United States)]. E-mail: gruszkiewicz@ornl.gov; Simonson, John M. [Oak Ridge National Laboratory, Chemical Sciences Division, P.O. Box 2008, Building 4500S MS-6110, Oak Ridge, TN 37831-6110 (United States)]. E-mail: simonsonjm@ornl.gov

2005-09-15

The Oak Ridge National Laboratory high-temperature isopiestic apparatus was outfitted with precise pressure gauges to allow for direct vapor pressure measurements. Vapor pressures over concentrated solutions of CaCl{sub 2}(aq), and CaBr{sub 2}(aq) were measured at temperatures between (380.15 and 523.15) K in the range of water activities between 0.2 and 0.85. Isopiestic molalities were used to determine osmotic coefficients at the conditions where NaCl reference standard solutions remained undersaturated. The main goal of this work was to improve the accuracy of isopiestic comparisons based on the calcium chloride reference standard. Osmotic coefficients for CaCl{sub 2}(aq) and CaBr{sub 2}(aq) calculated from both isopiestic and direct vapor pressure results were combined with the literature data and used to build general thermodynamic models based on a variant of extended Pitzer ion-interaction equations and valid at the saturation pressure of water. While these empirical models approach the accuracy of the experimental data in a wider range of concentrations and temperatures than any previously published equations, considerable amounts of accurate data and a substantial effort are required in order to obtain a satisfactory representation using power series-based virial equations. The effect of experimental uncertainties on the accuracy of the direct vapor pressure results is discussed, including in particular the error caused by the presence in the apparatus of a small amount of CO{sub 2}. The substantial decrease of the solubility product of CaCO{sub 3} in concentrated chloride solutions at temperatures above 423 K is a serious defect of calcium chloride as a water activity reference standard.

Theoretical study and rate constant calculation for the reactions of SH (SD) with Cl2, Br2, and BrCl.

Science.gov (United States)

Wang, Li; Liu, Jing-Yao; Li, Ze-Sheng; Sun, Chia-Chung

2005-01-30

The mechanisms of the SH (SD) radicals with Cl2 (R1), Br2 (R2), and BrCl (R3) are investigated theoretically, and the rate constants are calculated using a dual-level direct dynamics method. The optimized geometries and frequencies of the stationary points are calculated at the MP2/6-311G(d,p) and MPW1K/6-311G(d,p) levels. Higher-level energies are obtained at the approximate QCISD(T)/6-311++G(3df, 2pd) level using the MP2 geometries as well as by the multicoefficient correlation method based on QCISD (MC-QCISD) using the MPW1K geometries. Complexes with energies less than those of the reactants or products are located at the entrance or the exit channels of these reactions, which indicate that the reactions may proceed via an indirect mechanism. The enthalpies of formation for the species XSH/XSD (X = Cl and Br) are evaluated using hydrogenation working reactions method. By canonical variational transition-state theory (CVT), the rate constants of SH and SD radicals with Cl2, Br2, and BrCl are calculated over a wide temperature range of 200-2000 K at the a-QCISD(T)/6-311++G(3df, 2pd)//MP2/6-311G(d, p) level. Good agreement between the calculated and experimental rate constants is obtained in the measured temperature range. Our calculations show that for SH (SD) + BrCl reaction bromine abstraction (R3a or R3a') leading to the formation of BrSH (BrSD) + Cl in a barrierless process dominants the reaction with the branching ratios for channels 3a and 3a' of 99% at 298 K, which is quite different from the experimental result of k3a'/k3' = 54 +/- 10%. Negative activation energies are found at the higher level for the SH + Br2 and SH + BrCl (Br-abstraction) reactions; as a result, the rate constants show a slightly negative temperature dependence, which is consistent with the determination in the literature. The kinetic isotope effects for the three reactions are "inverse". The values of kH/kD are 0.88, 0.91, and 0.69 at room temperature, respectively, and they increase

The system K2NbF7-K2TiF6-KCl

International Nuclear Information System (INIS)

Kamenskaya, L.A.; Matveev, A.M.

1984-01-01

Using visual-polythermal and thermographical methods the ternary system K 2 NbF 7 -K 2 TiE 6 -KCl has been studied. Crystallization fields of initial components and the field of solid solutions of double compounds K 3 NbClF 7 and K 3 TiClF 6 are outlined. Ternary eutectics at 654 deg C, having the composition K 2 NbF 6 -41, K 2 TiP 6 -41, KCl-18 mol.%, is determined. Potassium fluoroniobate and fluorotitanate form continuous solid solutions unstable in the presence of the third component, potassium chloride

Activity coefficients of CaCl2 in (maltose + water) and (lactose + water) mixtures at 298.15 K

International Nuclear Information System (INIS)

Zhuo Kelei; Liu Hongxun; Zhang Honghao; Liu Yaohui; Wang Jianji

2008-01-01

Activity coefficients of CaCl 2 in disaccharide {(maltose, lactose) + water} mixtures at 298.15 K were determined by cell potentials. The molalities of CaCl 2 ranged from about 0.01 mol . kg -1 to 0.20 mol . kg -1 , the mass fractions of maltose from 0.05 to 0.25, and those of lactose from 0.025 to 0.125. The cell potentials were analyzed by using the Debye-Hueckel extended equation and the Pitzer equation. The activity coefficients obtained from the two theoretical models are in good agreement with each other. Gibbs free energy interaction parameters (g ES ) and salting constants (k S ) were also obtained. These were discussed in terms of the stereo-chemistry of saccharide molecules and the structural interaction model

Emulating exhalative chemistry: synthesis and structural characterization of ilinskite, Na[Cu5O2](SeO3)2Cl3, and its K-analogue

Science.gov (United States)

Kovrugin, Vadim M.; Siidra, Oleg I.; Colmont, Marie; Mentré, Olivier; Krivovichev, Sergey V.

2015-08-01

The K- and Na-synthetic analogues of the fumarolic mineral ilinskite have been synthesized by the chemical vapor transport (CVT) reactions method. The A[Cu5O2](SeO3)2Cl3 ( A + = K+, Na+) compounds crystallize in the orthorhombic space group Pnma: a = 18.1691(6) Å, b = 6.4483(2) Å, c = 10.5684(4) Å, V = 1238.19(7) Å3, R 1 = 0.018 for 1957 unique reflections with F > 4σ F for K[Cu5O2](SeO3)2Cl3 ( KI), and a = 17.7489(18) Å, b = 6.4412(6) Å, c = 10.4880(12) Å, V = 1199.0(2) Å3, R 1 = 0.049 for 1300 unique reflections with F > 4σ F for Na[Cu5O2](SeO3)2Cl3 ( NaI). The crystal structures of KI and NaI are based upon the [O2Cu5]6+ sheets consisting of corner-sharing (OCu4)6+ tetrahedra. The Na-for-K substitution results in the significant expansion of the interlayer space and changes in local coordination of some of the Cu2+ cations. The A + cation coordination changes from fivefold (for Na+) to ninefold (for K+). The CVT reactions method provides a unique opportunity to model physicochemical conditions existing in fumarolic environments and may be used not only to model exhalative processes, but also to predict possible mineral phases that may form in fumaroles. In particular, the K analogue of ilinskite is not known in nature, whereas it may well form from volcanic gases in a K-rich local geochemical environment.

Optimization and calculation of the MCl-ZnCl2 (M = Li, Na, K) phase diagrams

International Nuclear Information System (INIS)

Romero-Serrano, Antonio; Hernandez-Ramirez, Aurelio; Cruz-Ramirez, Alejandro; Hallen-Lopez, Manuel; Zeifert, Beatriz

2010-01-01

An earlier structural model for binary silicate melts and glasses is extended to zinc chloride-alkali metal chloride systems. The evaluation of the available thermodynamic and phase diagrams data for the MCl-ZnCl 2 (M = Li, Na, K) binary systems have been carried out using the structural model for the liquid phase. This thermodynamic model is based on the assumption that each alkali chloride produces the depolymerization of ZnCl 2 network with a characteristic free-energy change. A least-squares optimization program permits all available thermodynamic and phase diagram data to be optimized simultaneously. In this manner, data for these binary systems have been analysed and represented with a small number of parameters.

Basolateral K+ channels in airway epithelia. II. Role in Cl- secretion and evidence for two types of K+ channel

International Nuclear Information System (INIS)

McCann, J.D.; Welsh, M.J.

1990-01-01

We previously described a Ca2(+)-activated K+ channel (KCLIC) in airway epithelial cells. To determine whether the KCLIC channel is a basolateral membrane channel and to understand its role in Cl- secretion, we studied airway epithelial cells grown on permeable supports. When cells were stimulated with A23187, charybdotoxin (ChTX) inhibited Cl- secretion and 86Rb efflux at the same concentrations, indicating that the KCLIC channel is required for Ca2(+)-stimulated Cl- secretion. We also investigated the function of K+ channels in adenosine 3',5'-cyclic monophosphate-stimulated secretion. Addition of isoproterenol caused a biphasic increase in Cl- secretion; the time course of the transient component correlated with the time course of the isoproterenol-induced increase in Ca2+ concentration [( Ca2+]c). ChTX inhibited the transient component, but not the prolonged component of secretion; Ba2+ inhibited the sustained component. These results suggest that when cells are grown on permeable supports isoproterenol-induced secretion depends on activation of two types of K+ channel: the KCLIC channel that is stimulated initially and a ChTX-insensitive K+ channel that is stimulated during sustained secretion. This conclusion was supported by measurement of 86Rb efflux from cell monolayers

Cl- transport pathways regulated by Ca++, cAMP, and pH in human fibroblasts

International Nuclear Information System (INIS)

Lin, P.; Gruenstein, E.

1987-01-01

Under basal conditions Cl - efflux from human fibroblasts occurs with a rate constant of permeability of 0.08 min -1 . 50% of the basal efflux is due to Cl - /anion exchange and is DIDS inhibitable, 25% is due to Na + /K + /Cl - cotransport and is furosemide inhibitable, and 20% is due to an electrically conductive pathway. Increasing intracellular Ca ++ with A23187 stimulates Cl - efflux by 30%. This increase appears to occur entirely via an electrically conducting pathway, but unlike basal Cl - conductance, it is DIDS sensitive. Exposure of the cells to dibutyryl cAMP stimulates Cl - efflux by 15%. They do not yet know whether the cAMP stimulated pathway is electrically conductive, but the stimulation is additive with that caused by elevated Ca ++ suggesting that different pathways are activated. Elevation of intracellular pH by any of several standard methods increases Cl - efflux by as much as 700%. The pH effect appears to be mediated by a Cl - /anion exchange pathway since it is DIDS sensitive and electroneutral. Previous work from this laboratory describing a transient rapid efflux of Cl - followed by a slower efflux phase can now be explained as the result of a transient alkalinization of cells rather than as 2 subcellular Cl - compartments. This alkalinization occurs when cells are transferred from a 5% CO 2 atmosphere during 36 Cl - load to ambient CO 2 for efflux

Investigation of the magnetic structure of KFeCl3, KFeBr3, Rb2MnCl4, and Rb3Mn2Cl7 compounds with magnetic correlations in one and two dimensions

International Nuclear Information System (INIS)

Gurewitz, E.

1976-12-01

The crystallographic structure of KFeCl 3 and KFeBr 3 consists of (FeCl) - octahedra packed in isolated zigzagging chains. These compounds order antiferromagnetically at Tsub(N) approximately 16 deg K and Tsub(N) approximately 9.5 deg K, respectively. Below Tsub(N) the Fe 2+ magnetic moments within a chain are ferromagnetically coupled, parallel to the chain axis, while the chains are coupled antiferromagnetically. In the temperatures Tsub(N) 3 has magnetic correlations within the chains only, whereas the correlations between the chains are negligible. Moessbauer effect measurements at these temperatures show a distinct hyperfine magnetic splitting, characteristic of relaxation phenomena. Cs 2 MnCl 4 , Rb 2 MnCl 4 and Rb 3 Mn 2 Cl 7 belong to the Asub(n+1)Bsub(n)Xsub(3n+1) family of compounds, with the Dsub(4h)sup(17) space group. These compounds order antiferromagnetically at Tsub(N) approximately 55 deg K for Cs 2 MnCl 4 and Rb 2 MnCl 4 , and Tsub(N) approximately 64.5 deg K for Rb 3 Mn 2 Cl 7 . Below Tsub(N) each Mn 2+ moment is along the c-axis and is coupled antiferromagnetically to the moments of its nearest neighbours (nn). These compounds behave like a two-dimensional antiferromagnet at T >= Tsub(N). Neutron scans of the reciprocal space exhibit rods of reflections along c vectorsup(*). The negligible interactions between next nn sets of MnCl 2 layers, a distance c vector apart, yield both in Rb 2 MnCl 4 and in Rb 3 Mn 2 Cl 7 , two distinctive magnetic structures (polytypes) below Tsub(N). (author)

Elemental maps in human allantochorial placental vessels cells: 1. High K{sup +} and acetylcholine effects

Energy Technology Data Exchange (ETDEWEB)

Michelet-Habchi, C. E-mail: michelet@cenbg.in2p3.fr; Barberet, Ph.; Dutta, R.K.; Guiet-Bara, A.; Bara, M.; Moretto, Ph

2003-09-01

Regulation of vascular tone in the fetal extracorporeal circulation most likely depends on circulating hormones, local paracrine mechanisms and changes in membrane potential of vascular smooth muscle cells (VSMCs) and of vascular endothelial cells (VECs). The membrane potential is a function of the physiological activities of ionic channels (particularly, K{sup +} and Ca{sup 2+} channels in these cells). These channels regulate the ionic distribution into these cells. Micro-particle induced X-ray emission (PIXE) analysis was applied to determine the ionic composition of VSMC and of VEC in the placental human allantochorial vessels in a physiological survival medium (Hanks' solution) modified by the addition of acetylcholine (ACh: which opens the calcium-sensitive K{sup +} channels, K{sub Ca}) and of high concentration of K{sup +} (which blocks the voltage-sensitive K{sup +} channels, K{sub df}). In VSMC (media layer), the addition of ACh induced no modification of the Na, K, Cl, P, S, Mg and Ca concentrations and high K{sup +} medium increased significantly the Cl and K concentrations, the other ion concentrations remaining constant. In endothelium (VEC), ACh addition implicated a significant increase of Na and K concentration, and high K{sup +} medium, a significant increase in Cl and K concentration. These results indicated the importance of K{sub df}, K{sub Ca} and K{sub ATP} channels in the regulation of K{sup +} intracellular distribution in VSMC and VEC and the possible intervention of a Na-K-2Cl cotransport and corroborated the previous electrophysiological data.

EFFECT OF DIFFERENT K2 HPO4, NaCl LEVELS AND TWO DIFFERENT TEMPARATURES ON SOME EMULSION PROPERTIES OF GOAT MEAT

OpenAIRE

Mustafa KARAKAYA; Hüsnü Yusuf GÖKALP; Ramazan BAYRAK

1996-01-01

Different levels of K2 HPO4 (0.00 %, 0.25 % and 0.50 %) and NaCl (2.5 % and 3.0 %) were added into goat meat, at the two different temperatures (11o C and 18o C) in order to investigate the emulsion properties in the model emulsion system. Emulsion capacity (EK), emulsion viscocity (EV), emulsion stability ratio (ES), the ratio of separated water (ESO) and oil (EYO) ratio from the emulsion, and the emulsion pH were determined. K2 HPO4 and NaCl levels and the oil temperatures have significant ...

Compensatory role of the NBCn1 sodium/bicarbonate cotransporter on Ca2+-induced mitochondrial swelling in hypertrophic hearts.

Science.gov (United States)

Vargas, Lorena A; Velasquez, Fernanda Carrizo; Alvarez, Bernardo V

2017-03-01

NBC Na + /HCO 3 - cotransporter (NBCn1) and NHE1 Na + /H + exchanger have been associated with cardiac disorders and recently located in coronary endothelial cells (CEC) and cardiomyocytes mitochondria, respectively. Mitochondrial NHE1 blockade delays permeability transition pore (MPTP) opening and reduces superoxide levels, two critical events exacerbated in cells of diseased hearts. Conversely, activation of NBCn1 prevented apoptosis in CEC subjected to ischemic stress. We characterized the role of the NHE1 and NBCn1 transporters in heart mitochondria from hypertrophic (SHR) and control (Wistar) rats. Expression of NHE1 was analyzed in left ventricular mitochondrial lysates (LVML), by immunoblots. NHE1 expression increased by ~40% in SHR compared to control (P < 0.05, n = 4). To examine NHE1-mediated Na + /H + exchange activity in cardiac hypertrophy, mitochondria were loaded with BCECF-AM dye and the maximal rate of pHm change measured after the addition of 50 mM NaCl. SHR mitochondria had greater changes in pHm compared to Wistar, 0.10 ± 0.01 vs. 0.06 ± 0.01, respectively (P < 0.05, n = 5). In addition, mitochondrial suspensions from SHR and control myocardium were exposed to 200 μM CaCl 2 to induce MPTP opening (light-scattering decrease, LSD) and swelling. Surprisingly, SHR rats showed smaller LSD and a reduction in mitochondrial swelling, 67 ± 10% (n = 15), compared to control, 100 ± 8% (n = 13). NBC inhibition with S0859 (1 μM) significantly increased swelling in both control 139 ± 10% (n = 8) and SHR 115 ± 10% (n = 4). Finally, NBCn1 Na + /HCO 3 - cotransporter increased by twofold its expression in SHR LVML, compared to normal (P < 0.05, n = 5). We conclude that increased NBCn1 activity may play a compensatory role in hypertrophic hearts, protecting mitochondria from Ca 2+ -induced MPTP opening and swelling.

Atmospheric degradation of industrial fluorinated acrylates and methacrylates with Cl atoms at atmospheric pressure and 298 K

Science.gov (United States)

Rivela, Cynthia B.; Blanco, María B.; Teruel, Mariano A.

2018-04-01

The gas-phase reaction of Cl atom with 2,2,2-trifluoroethylacrylate (k1), 1,1,1,3,3,3-hexafluoroisopropylacrylate (k2), 2,2,2-trifluoroethylmethacrylate (k3) and 1,1,1,3,3,3-hexafluoroisopropylmethacrylate (k4), have been investigated at 298 K and 1 atm using the relative method by gas chromatography coupled with flame ionization detection (GC-FID). The values obtained are (in cm3 molecule-1 s-1): k1(Cl+CH2=CHC(O)OCH2CF3) = (2.41 ± 0.57) × 10-10, k2(Cl+CH2=CHC(O)OCH(CF3)2) = (1.39 ± 0.34) × 10-10, k3(Cl+CH2=C(CH3)C(O)OCH2CF3) = (2.22 ± 0.45) × 10-10, and k4(Cl +CH2=C(CH3)C(O)OCH(CF3)2 = (2.44 ± 0.52) × 10-10. Products identification studies were performed by solid-phase microextraction (SPME) method, with on-fiber products derivatization using o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride, coupled with gas chromatography with mass spectrometry detection (GC-MS). Chloroacetone, trifluoroacetaldehyde and formaldehyde were observed as degradation products and a general mechanism is proposed. Additionally, reactivity trends and atmospheric implications are discussed. Significant ozone photochemical potentials (POCP) and acidification potentials lead to local and or regional impact of the esters under study although is expected to a have a minor impact on global warming and climate change.

The effects of sodium-glucose co-transporter 2 inhibitors in patients with type 2 diabetes

DEFF Research Database (Denmark)

Storgaard, Heidi; Gluud, Lise Lotte; Christensen, Mikkel

2014-01-01

INTRODUCTION: Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) increase urinary glucose excretion through a reduced renal glucose reabsorption. We plan to perform a systematic review of SGLT-2i for treatment of type 2 diabetes. METHODS AND ANALYSIS: A systematic review with meta-analyses of r......INTRODUCTION: Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) increase urinary glucose excretion through a reduced renal glucose reabsorption. We plan to perform a systematic review of SGLT-2i for treatment of type 2 diabetes. METHODS AND ANALYSIS: A systematic review with meta......-analyses of randomised clinical trials on SGLT-2i versus placebo, other oral glucose lowering drugs or insulin for patients with type 2 diabetes will be performed. The primary end point will be the glycated haemoglobin. Secondary end points will include changes in body weight, body mass index, fasting plasma glucose......, plasma cholesterol, kidney and liver blood tests, blood pressure and adverse events. Electronic (the Cochrane Library, MEDLINE, EMBASE and the Science Citation Index) and manual searches will be performed. Meta-analyses will be performed and the results presented as mean differences for continuous...

Optimization and calculation of the MCl-ZnCl{sub 2} (M = Li, Na, K) phase diagrams

Energy Technology Data Exchange (ETDEWEB)

Romero-Serrano, Antonio, E-mail: romeroipn@hotmail.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico, D.F. (Mexico); Hernandez-Ramirez, Aurelio, E-mail: aurelioh@hotmail.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico, D.F. (Mexico); Cruz-Ramirez, Alejandro, E-mail: alcruzr@ipn.mx [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico, D.F. (Mexico); Hallen-Lopez, Manuel, E-mail: j_hallen@yahoo.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico, D.F. (Mexico); Zeifert, Beatriz, E-mail: bzeifert@yahoo.com [Metallurgy and Materials Department, Instituto Politecnico Nacional-ESIQIE, Apdo. P. 118-431, 07051 Mexico, D.F. (Mexico)

2010-10-20

An earlier structural model for binary silicate melts and glasses is extended to zinc chloride-alkali metal chloride systems. The evaluation of the available thermodynamic and phase diagrams data for the MCl-ZnCl{sub 2} (M = Li, Na, K) binary systems have been carried out using the structural model for the liquid phase. This thermodynamic model is based on the assumption that each alkali chloride produces the depolymerization of ZnCl{sub 2} network with a characteristic free-energy change. A least-squares optimization program permits all available thermodynamic and phase diagram data to be optimized simultaneously. In this manner, data for these binary systems have been analysed and represented with a small number of parameters.

Dendritic silica nanomaterials (KCC-1) with fibrous pore structure possess high DNA adsorption capacity and effectively deliver genes in vitro.

Science.gov (United States)

Huang, Xiaoxi; Tao, Zhimin; Praskavich, John C; Goswami, Anandarup; Al-Sharab, Jafar F; Minko, Tamara; Polshettiwar, Vivek; Asefa, Tewodros

2014-09-16

The pore size and pore structure of nanoporous materials can affect the materials' physical properties, as well as potential applications in different areas, including catalysis, drug delivery, and biomolecular therapeutics. KCC-1, one of the newest members of silica nanomaterials, possesses fibrous, large pore, dendritic pore networks with wide pore entrances, large pore size distribution, spacious pore volume and large surface area--structural features that are conducive for adsorption and release of large guest molecules and biomacromolecules (e.g., proteins and DNAs). Here, we report the results of our comparative studies of adsorption of salmon DNA in a series of KCC-1-based nanomaterials that are functionalized with different organoamine groups on different parts of their surfaces (channel walls, external surfaces or both). For comparison the results of our studies of adsorption of salmon DNA in similarly functionalized, MCM-41 mesoporous silica nanomaterials with cylindrical pores, some of the most studied silica nanomaterials for drug/gene delivery, are also included. Our results indicate that, despite their relatively lower specific surface area, the KCC-1-based nanomaterials show high adsorption capacity for DNA than the corresponding MCM-41-based nanomaterials, most likely because of KCC-1's large pores, wide pore mouths, fibrous pore network, and thereby more accessible and amenable structure for DNA molecules to diffuse through. Conversely, the MCM-41-based nanomaterials adsorb much less DNA, presumably because their outer surfaces/cylindrical channel pore entrances can get blocked by the DNA molecules, making the inner parts of the materials inaccessible. Moreover, experiments involving fluorescent dye-tagged DNAs suggest that the amine-grafted KCC-1 materials are better suited for delivering the DNAs adsorbed on their surfaces into cellular environments than their MCM-41 counterparts. Finally, cellular toxicity tests show that the KCC-1-based

Urine concentrating mechanism: impact of vascular and tubular architecture and a proposed descending limb urea-Na+ cotransporter

Science.gov (United States)

Dantzler, William H.; Pannabecker, Thomas L.

2012-01-01

We extended a region-based mathematical model of the renal medulla of the rat kidney, previously developed by us, to represent new anatomic findings on the vascular architecture in the rat inner medulla (IM). In the outer medulla (OM), tubules and vessels are organized around tightly packed vascular bundles; in the IM, the organization is centered around collecting duct clusters. In particular, the model represents the separation of descending vasa recta from the descending limbs of loops of Henle, and the model represents a papillary segment of the descending thin limb that is water impermeable and highly urea permeable. Model results suggest that, despite the compartmentalization of IM blood flow, IM interstitial fluid composition is substantially more homogeneous compared with OM. We used the model to study medullary blood flow in antidiuresis and the effects of vascular countercurrent exchange. We also hypothesize that the terminal aquaporin-1 null segment of the long descending thin limbs may express a urea-Na+ or urea-Cl− cotransporter. As urea diffuses from the urea-rich papillary interstitium into the descending thin limb luminal fluid, NaCl is secreted via the cotransporter against its concentration gradient. That NaCl is then reabsorbed near the loop bend, raising the interstitial fluid osmolality and promoting water reabsorption from the IM collecting ducts. Indeed, the model predicts that the presence of the urea-Na+ or urea- Cl− cotransporter facilitates the cycling of NaCl within the IM and yields a loop-bend fluid composition consistent with experimental data. PMID:22088433

EFFECT OF DIFFERENT K2 HPO4, NaCl LEVELS AND TWO DIFFERENT TEMPARATURES ON SOME EMULSION PROPERTIES OF GOAT MEAT

Directory of Open Access Journals (Sweden)

Mustafa KARAKAYA

1996-03-01

Full Text Available Different levels of K2 HPO4 (0.00 %, 0.25 % and 0.50 % and NaCl (2.5 % and 3.0 % were added into goat meat, at the two different temperatures (11o C and 18o C in order to investigate the emulsion properties in the model emulsion system. Emulsion capacity (EK, emulsion viscocity (EV, emulsion stability ratio (ES, the ratio of separated water (ESO and oil (EYO ratio from the emulsion, and the emulsion pH were determined. K2 HPO4 and NaCl levels and the oil temperatures have significant effect (p

Soft modes and phase transition at 74K in Rb2ZnCl4

International Nuclear Information System (INIS)

Mashiyama, Hiroyuki; Sugimoto, Kousirou; Oohara, Yasuaki; Yoshizawa, Hideki.

1993-01-01

The orthorhombic to monoclinic transition at T m = 73.5K in Rb 2 ZnCl 4 is investigated by means of neutron scattering at JRR-3M. The superlattice reflections observed below T m increases as (T m - T) 2β with β = 0.38. The dispersion relations of low energy are determined both above and below T m . The softening of phonon frequency is observed around the Brillouin zone-boundary. The square of the energy transfer of the soft phonon obeys a linear relation on temperature. (author)

Activation of ion transport systems during cell volume regulation

International Nuclear Information System (INIS)

Eveloff, J.L.; Warnock, D.G.

1987-01-01

This review discusses the activation of transport pathways during volume regulation, including their characteristics, the possible biochemical pathways that may mediate the activation of transport pathways, and the relations between volume regulation and transepithelial transport in renal cells. Many cells regulate their volume when exposed to an anisotonic medium. The changes in cell volume are caused by activation of ion transport pathways, plus the accompanying osmotically driven water movement such that cell volume returns toward normal levels. The swelling of hypertonically shrunken cells is termed regulatory volume increase (RVI) and involves an influx of NaCl into the cell via either activation of Na-Cl, Na-K-2Cl cotransport systems, or Na + -H + and Cl - -HCO 3 - exchangers. The reshrinking of hypotonically swollen cells is termed regulatory volume decrease (RVD) and involves an efflux of KCl and water from the cell by activation of either separate K + and Cl - conductances, a K-Cl cotransport system, or parallel K + -H + and Cl - -HCO 3 - exchangers. The biochemical mechanisms involved in the activation of transport systems are largely unknown, however, the phosphoinositide pathway may be implicated in RVI; phorbol esters, cGMP, and Ca 2+ affect the process of volume regulation. Renal tubular cells, as well as the blood cells that transverse the medulla, are subjected to increasing osmotic gradients from the corticomedullary junction to the papillary tip, as well as changing interstitial and tubule fluid osmolarity, depending on the diuretic state of the animal. Medullary cells from the loop of Henle and the papilla can volume regulate by activating Na-K-2Cl cotransport or Na + -H + and Cl - -HCO 3 - exchange systems

Kinetic isotope effects in the gas phase reactions of OH and Cl with CH3Cl, CD3Cl, and 13CH3Cl

Directory of Open Access Journals (Sweden)

A. A. Gola

2005-01-01

Full Text Available The kinetic isotope effects in the reactions of CH3Cl, 13CH3Cl and CD3Cl with OH radicals and Cl atoms were studied in relative rate experiments at 298±2 K and 1013±10 mbar. The reactions were carried out in a smog chamber using long path FTIR detection and the spectroscopic data analyzed employing a non-linear least squares spectral fitting method using measured high-resolution infrared spectra as well as absorption cross sections from the HITRAN database. The reaction rates of 13CH3Cl and CD3Cl with OH and Cl were determined relative to CH3Cl as: kOH+CH3ClkOH+CH3Cl/kOH+13CH3Cl}kOH+13CH3Cl=1.059±0.008, kOH+CH3ClkOH+CH3Cl/kOH+CD3ClkOH+CD3Cl=3.9±0.4, kCl+CH3ClkCl+CH3Cl/kCl+13CH3ClkCl+13CH3Cl =1.070±0.010 and kCl+CH3ClkCl+CH3Cl/kCl+CD3ClkCl+CD3Cl=4.91±0.07. The uncertainties given are 2σ from the statistical analyses and do not include possible systematic errors. The unexpectedly large 13C kinetic isotope effect in the OH reaction of CH3Cl has important implications for the global emission inventory of CH3Cl.

Sodium-glucose cotransporter 2 (SGLT-2) inhibitors for patients with Type 2 diabetes

DEFF Research Database (Denmark)

Røder, Michael Einar; Storgaard, Heidi; Rungby, Jørgen

2016-01-01

The sodium-glucose cotransporter 2 inhibitor (SGLT-2i)-class is efficacious as monotherapy and as add-on therapy with an expected lowering of the glycated haemoglobin (HbA1c) concentration of approximately 7 mmol/mol. Side effects relate to the mode of action, genital infections are the main...... problem. Extremely rare cases of ketoacidosis are reported, mostly in patients with Type 1 diabetes. One SGLT-2i, empagliflozin, has been shown to reduce cardiovascular mortality and progression of kidney disease in patients with Type 2 diabetes and cardiovascular disease. Outcome trials for other SGLT-2i...... are pending. SGLT-2i are now in guidelines as a possible second-line therapy or in case of metformin intolerance....

Determination of hydrolysis constants for gadolinium in ion strength media 2M of NaCl, NaClO4 and KCl at 303 K

International Nuclear Information System (INIS)

Serna M, S.; Jimenez R, M.; Solache R, M.

1999-01-01

This work was made with the purpose to extend information about the hydrolysis constants of gadolinium (III) in ion strength media 2M of NaCl, NaClO 4 , KCl at 303 K using the potentiometric method for this determination, and analysing starting from those data, the influence of anions and cations. It is concluded that the media which were determined the hydrolysis constants are very important and it is recommended the sodium perchlorate as the more adequate salt for those determinations. Also it was obtained the distribution diagrams of chemical species in each one of the media studied. (Author)

The collectins CL-L1, CL-K1 and CL-P1, and their roles in complement and innate immunity

DEFF Research Database (Denmark)

Hansen, Soren W K; Ohtani, Katsuki; Roy, Nitai

2016-01-01

as CL-LK) and its activation of the lectin pathway via MASPs, drew new attention in the complement biology, which was further strengthened by the observed interactions between CL-P1 and CRP-C1q-factor H or properdin. Deficiency of either CL-K1 or MASP-3 has been demonstrated in 3MC syndrome patients...

Activity coefficients of CaCl{sub 2} in (maltose + water) and (lactose + water) mixtures at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Zhuo Kelei [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)], E-mail: klzhuo@263.net; Liu Hongxun; Zhang Honghao; Liu Yaohui; Wang Jianji [School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

2008-05-15

Activity coefficients of CaCl{sub 2} in disaccharide {l_brace}(maltose, lactose) + water{r_brace} mixtures at 298.15 K were determined by cell potentials. The molalities of CaCl{sub 2} ranged from about 0.01 mol . kg{sup -1} to 0.20 mol . kg{sup -1}, the mass fractions of maltose from 0.05 to 0.25, and those of lactose from 0.025 to 0.125. The cell potentials were analyzed by using the Debye-Hueckel extended equation and the Pitzer equation. The activity coefficients obtained from the two theoretical models are in good agreement with each other. Gibbs free energy interaction parameters (g{sub ES}) and salting constants (k{sub S}) were also obtained. These were discussed in terms of the stereo-chemistry of saccharide molecules and the structural interaction model.

Luminescence of the SrCl2:Pr crystals under high-energy excitation

International Nuclear Information System (INIS)

Antonyak, O.T.; Voloshinovskii, A.S.; Vistovskyy, V.V.; Stryganyuk, G.B.; Kregel, O.P.

2014-01-01

The present research was carried out in order to elucidate the mechanisms of energy transfer from the crystal lattice to Pr 3+ ions in SrCl 2 . The luminescence excitation and emission spectra as well as luminescence kinetics of the SrCl 2 :Pr single crystals containing 0.2 mol% Pr were investigated at 300 and 10 K using the vacuum ultraviolet (VUV) synchrotron radiation. The X-ray excited luminescence spectra of the SrCl 2 :Pr (C Pr =0.2 and 0.5 mol%) and SrCl 2 :Pr, K (C Pr =1.5 mol%; C K =1.5 mol%) crystals were studied at 294 and 80 K. Under optical excitation of the samples in the Pr 3+ absorption bands, there were observed five fast ultraviolet emissions assigned to the 4f 1 5d→4f 2 transitions, and two long-wave bands corresponding to the f–f transitions. Furthermore, the intrinsic emission bands of SrCl 2 were observed at 10 K. The X-ray excited luminescence spectrum of the SrCl 2 :Pr crystal containing 0.2 mol% Pr, besides intrinsic emission band near 400 nm, has got a long-wave band at about 490 nm of the Pr 3+ centers. There were not observed any emission bands of the Pr 3+ centers corresponding to the 4f 1 5d–4f 2 transitions in the X-ray excited luminescence spectrum of the SrCl 2 :Pr crystal. The possible mechanisms of energy transfer from the SrCl 2 matrix to the Pr 3+ centers are discussed. -- Highlights: • Spectral-luminescent properties of SrCl 2 :Pr have been investigated. • The identification of emission 4f–4f and 5d–4f bands of Pr 3+ ions was performed. • Adding of potassium prevents clustering of the Pr 3+ centers in the SrCl 2 :Pr, K crystals. • Under X-ray excitation at 80–300 K only Pr 3+ 4f–4f and intrinsic emission is observed

Muscle K+, Na+, and Cl- disturbances and Na+-K+ pump inactivation: implications for fatigue

DEFF Research Database (Denmark)

McKenna, Michael J; Bangsbo, Jens; Renaud, Jean-Marc

2008-01-01

(+)-ATPase activity during exercise stabilizes Na(+) and K(+) concentration gradients and membrane excitability and thus protects against fatigue. However, during intense contraction some Na(+)-K(+) pumps are inactivated and together with further ionic disturbances, likely precipitate muscle fatigue.......Membrane excitability is a critical regulatory step in skeletal muscle contraction and is modulated by local ionic concentrations, conductances, ion transporter activities, temperature, and humoral factors. Intense fatiguing contractions induce cellular K(+) efflux and Na(+) and Cl(-) influx......, causing pronounced perturbations in extracellular (interstitial) and intracellular K(+) and Na(+) concentrations. Muscle interstitial K(+) concentration may increase 1- to 2-fold to 11-13 mM and intracellular K(+) concentration fall by 1.3- to 1.7-fold; interstitial Na(+) concentration may decline by 10 m...

Mechanism of mercurial inhibition of sodium-coupled alanine uptake in liver plasma membrane vesicles from Raja erinacea

International Nuclear Information System (INIS)

Sellinger, M.; Ballatori, N.; Boyer, J.L.

1991-01-01

In mammalian hepatocytes the L-alanine carrier contains a sulfhydryl group that is essential for its activity and is inhibited by mercurials. In hepatocytes of the evolutionarily primitive little skate (Raja erinacea), HgCl2 inhibits Na(+)-dependent alanine uptake and Na+/K(+)-ATPase and increase K+ permeability. To distinguish between direct effects of HgCl2 on the Na(+)-alanine cotransporter and indirect effects on membrane permeability, [3H]alanine transport was studied in plasma membrane vesicles. [3H]Alanine uptake was stimulated by an out-to-in Na+ but not K+ gradient and was saturable confirming the presence of Na(+)-alanine cotransport in liver plasma membranes from this species. Preincubation of the vesicles with HgCl2 for 5 min reduced initial rates of Na(+)-dependent but not Na(+)-independent alanine uptake in a dose-dependent manner (10-200 microM). In the presence of equal concentrations of NaCl or KCl inside and outside of the vesicles, 75 microM HgCl2 directly inhibited sodium-dependent alanine-[3H]alanine exchange, demonstrating that HgCl2 directly affected the alanine cotransporter. Inhibition of Na(+)-dependent alanine uptake by 30 microM HgCl2 was reversed by dithiothreitol (1 mM). HgCl2 (10-30 microM) also increased initial rates of 22Na uptake (at 5 sec), whereas 22Na uptake rates were decreased at HgCl2 concentrations greater than 50 microM. Higher concentrations of HgCl2 (100-200 microM) produced nonspecific effects on vesicle integrity. These studies indicate that HgCl2 inhibits Na(+)-dependent alanine uptake in skate hepatocytes by three different concentration-dependent mechanisms: direct interaction with the transporters, dissipation of the driving force (Na+ gradient), and loss of membrane integrity

(Solid + liquid) phase equilibria of (Ca(H2PO2)2 + CaCl2 + H2O) and (Ca(H2PO2)2 + NaH2PO2 + H2O) ternary systems at T = 323.15 K

International Nuclear Information System (INIS)

Cao, Hong-yu; Zhou, Huan; Bai, Xiao-qin; Ma, Ruo-xin; Tan, Li-na; Wang, Jun-min

2016-01-01

Graphical abstract: Solubility diagram of the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system at T = (323.15 and 298.15) K. - Highlights: • Phase diagrams of Ca 2+ -H 2 PO 2 − -Cl − -H 2 O, Ca 2+ -Na + -H 2 PO 2 − -H 2 O at 323.15 K were obtained. • Incompatible double salt of NaCa(H 2 PO 2 ) 3 in Ca 2+ -Na + -H 2 PO 2 − -H 2 O system was determined. • Density diagram of the corresponding liquid were simultaneously measured. - Abstract: Calcium hypophosphite has been widely used as an anti-corrosive agent, flame retardant, fertilizer, assistant for Ni electroless plating, and animal nutritional supplement. High purity calcium hypophosphite can be synthesized via the replacement reaction of sodium hypophosphite and calcium chloride. In this work, the (solid + liquid) phase equilibria of (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) and (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) ternary systems at T = 323.15 K were studied experimentally via the classical isothermal solubility equilibrium method, and the phase diagrams for these two systems were obtained. It was found that two solid salts of CaCl 2 ·2H 2 O and Ca(H 2 PO 2 ) 2 exist in the (Ca(H 2 PO 2 ) 2 + CaCl 2 + H 2 O) system, and three salts of Ca(H 2 PO 2 ) 2 , NaH 2 PO 2 ·H 2 O and one incompatible double salt, NaCa(H 2 PO 2 ) 3 occur in the (Ca(H 2 PO 2 ) 2 + NaH 2 PO 2 + H 2 O) system.

Sodium-glucose cotransporter (SGLT)-2-inhibitorer til patienter med type 2-diabetes

DEFF Research Database (Denmark)

Røder, Michael Einar; Storgaard, Heidi; Rungby, Jørgen

2016-01-01

The sodium-glucose cotransporter 2 inhibitor (SGLT-2i)-class is efficacious as monotherapy and as add-on therapy with an expected lowering of the glycated haemoglobin (HbA1c) concentration of approximately 7 mmol/mol. Side effects relate to the mode of action, genital infections are the main...... problem. Extremely rare cases of ketoacidosis are reported, mostly in patients with Type 1 diabetes. One SGLT-2i, empagliflozin, has been shown to reduce cardiovascular mortality and progression of kidney disease in patients with Type 2 diabetes and cardiovascular disease. Outcome trials for other SGLT-2i...... are pending. SGLT-2i are now in guidelines as a possible second-line therapy or in case of metformin intolerance....

Silicon oxynitrides of KCC-1, SBA-15 and MCM-41 for CO 2 capture with excellent stability and regenerability

KAUST Repository

Patil, Umesh

2012-01-01

We report the use of silicon oxynitrides as novel adsorbents for CO 2 capture. Three series of functionalized materials based on KCC-1, SBA-15 and MCM-41 with Si-NH 2 groups were prepared using a simple one-step process via thermal ammonolysis using ammonia gas, and they demonstrated excellent CO 2 capture capabilities. These materials overcome several limitations of conventional amine-grafted mesoporous silica. They offer good CO 2 capture capacity, faster adsorption-desorption kinetics, efficient regeneration and reuse, more crucially excellent thermal and mechanical stability even in oxidative environments, and a clean and green synthesis route, which allows the overall CO 2 capture process to be practical and sustainable. This journal is © The Royal Society of Chemistry 2012.

Structure-activity relationships of bumetanide derivatives: correlation between diuretic activity in dogs and inhibition of the human NKCC2A transporter.

Science.gov (United States)

Lykke, Kasper; Töllner, Kathrin; Römermann, Kerstin; Feit, Peter W; Erker, Thomas; MacAulay, Nanna; Löscher, Wolfgang

2015-06-23

The N-K-Cl cotransporters (NKCCs) mediate the coupled, electroneutral movement of Na + , K + and Cl - ions across cell membranes. There are two isoforms of this cation co-transporter, NKCC1 and NKCC2. NKCC2 is expressed primarily in the kidney and is the target of diuretics such as bumetanide. Bumetanide was discovered by screening ∼5000 3-amino-5-sulfamoylbenzoic acid derivatives, long before NKCC2 was identified in the kidney. Therefore, structure-activity studies on effects of bumetanide derivatives on NKCC2 are not available. In this study, the effect of a series of diuretically active bumetanide derivatives was investigated on human NKCC2 variant A (hNKCC2A) expressed in Xenopus laevis oocytes. Bumetanide blocked hNKCC2A transport with an IC 50 of 4 μM. There was good correlation between the diuretic potency of bumetanide and its derivatives in dogs and their inhibition of hNKCC2A (r 2 = 0.817; P human NKCC2 splice variants, and may lead to the discovery of novel high-ceiling diuretics. © 2015 The British Pharmacological Society.

Sodium-glucose cotransporter 2 inhibitor use: A pharmaco-ergonomic qualification tool

Directory of Open Access Journals (Sweden)

Sanjay Kalra

2017-01-01

Full Text Available Pharmaco-ergonomics implies tailoring the drug therapy to an individual patient's requirement(s. The development of sodium-glucose cotransporter 2 inhibitor (SGLT2-i agents has impelled multiple clinical considerations, in the management of type-2 diabetes. This paper attempts to summarize the pharmaco-ergonomic considerations for these agents, in the form of an SGLT2-i qualification tool, based on a clinical score. This tool may serve as a simple and inexpensive practical guide, to optimize the risk-benefit considerations for SGLT2-i agents.

An EPR investigation of the dynamic Jahn-Teller effect in SrCl2:y(2 plus) and SrCl2:Sc(2 plus)

Science.gov (United States)

Herrington, J. R.; Estle, T. L.; Boatner, L. A.

1972-01-01

EPR spectra have been observed for SrCl2:Y(2+) and SrCl2:Sc(2+) at liquid helium temperatures. At 1.2 K the spectra were dominated by anisotropic hyperfine patterns whose lineshapes and angular dependences were explained using second order solutions of the effective Hamiltonian for an isolated 2Eg state split by large random internal strains. Pronounced asymmetries in some of the strin produced lineshapes for Srcl2:Sc(2+) are shown to result from second order terms in the solution of the effective Hamiltonian. Coexisting with the anisotropic hyperfine patterns are weak nearly isotropic hyperfine patterns with typical lineshapes. Variations in the apparent intensity of lines in these weak hyperfine patterns as functions of the applied magnetic field direction and temperature imply that these lines result from averaging by vibronic relaxation of a portion of the anisotropic pattern. The effective Hamiltonian parameters for SrCl2:La(2+), SrCl2:y(2+), and SrCl2:SC(2+) are analyzed in terms of crystal field theory modified to include a dynamic Jahn-Teller effect.

Bonding in d9 complexes derived from EPR: Application to CuCl2-4, CuBr2-4, and CdCl2:Cu2+

Science.gov (United States)

Aramburu, J. A.; Moreno, M.

1985-12-01

In this work are reported the theoretical expressions for the [g], hyperfine, and superhyperfine (shf) tensors of a d9 square-planar complex within a molecular orbital (MO) scheme. These expressions include contributions arising from crystal field and charge transfer excitations calculated up to third and second order perturbations, respectively. This makes the present framework more general than those previously used. Through those expressions we have derived from the experimental EPR and optical data the MO coefficients corresponding to the valence b1g(x2-y2), b2g(xy), and eg(xz,yz) levels and also the core polarization contribution K to the hyperfine tensor for the systems CuCl2-4, CuBr2-4, and CdCl2:Cu2+. The 3d charge obtained for CuCl2-4 is equal to 0.61, 0.83, and 0.85 for the antibonding 3b1g, 2b2g, and 2eg levels, respectively. These figures are much closer to the Xα results by Bencini and Gatteschi [J. Am. Chem. Soc. 105, 5535 (1983)] than to those by Desjardins et al. [J. Am. Chem. Soc. 105, 4590 (1983)]. The σ and π covalency for CuBr2-4 are both higher than for CuCl2-4 in accord to the lower electronegativity for bromine. However, only for the antibonding 3b1g level of CuBr2-4 have we obtained an electronic charge lying mainly on ligands. The covalency of CdCl2:Cu2+ is smaller than that found for CuCl2-4, a fact associated to a higher metal-ligand distance for the former. Evidence of this statement are also given from the analysis of crystal-field spectra and isotropic shf constant. The values of K derived for CuCl2-4 (128.1×10-4 cm-1), CuBr2-4 (103.6×10-4 cm-1), and CdCl2:Cu2+ (123.9×10-4 cm-1) point out the dependence of K on the equatorial covalency but also on the existence of axial ligands. The [g] tensor of CuBr2-4 is dominated by the charge transfer contribution while the crystal field one is negative. Finally an analysis of the importance of each one of the involved contributions to the spin-Hamiltonian parameters is reported for the

K+ transport and membrane potentials in isolated rat parotid acini

International Nuclear Information System (INIS)

Nauntofte, B.; Dissing, S.

1988-01-01

42K+ transport properties of isolated rat parotid acini were characterized concomitant with measurements of membrane potentials (Em) by means of the fluorescent dye diSC3-(5). In unstimulated acini suspended in a 5 mM K+ buffer, Em was governed by the K+ and Cl- gradients and amounted to about -59 mV, a value that remained unaffected on cholinergic stimulation. In unstimulated acini, 42K+ influx was largely mediated by the Na+-K+ pump, and the residual influxes were mediated by a bumetanide-sensitive component (cotransport system) and by K+ channels. Efflux of 42K+ was largely mediated by a bumetanide-sensitive component and by K+ channels. In the unstimulated state, the cotransport system was mediating K+-K+ exchange without contributing to the net uptake of K+. Within 10 s after stimulation, a approximately 10-fold increase in the acinar K+ conductance (gK) occurred, resulting in a rapid net efflux of K+ that amounted to approximately 3.8 mmol.l cells-1.s-1. Measurements of 42K+ fluxes as a function of the external K+ concentration revealed that in the stimulated state gK increases when external K+ is raised from 0.7 to 10 mM, consistent with an activation of acinar gK by the binding of external K+ to the channel. 42K+ flux ratios as well as the effect of the K+ channel inhibitor from scorpion venom (LQV) suggest that approximately 90% of K+ transport in the stimulated state is mediated by ''maxi'' K+ channels

Single-Crystal Growth of Cl-Doped n-Type SnS Using SnCl2 Self-Flux.

Science.gov (United States)

Iguchi, Yuki; Inoue, Kazutoshi; Sugiyama, Taiki; Yanagi, Hiroshi

2018-06-05

SnS is a promising photovoltaic semiconductor owing to its suitable band gap energy and high optical absorption coefficient for highly efficient thin film solar cells. The most significant carnage is demonstration of n-type SnS. In this study, Cl-doped n-type single crystals were grown using SnCl 2 self-flux method. The obtained crystal was lamellar, with length and width of a few millimeters and thickness ranging between 28 and 39 μm. X-ray diffraction measurements revealed the single crystals had an orthorhombic unit cell. Since the ionic radii of S 2- and Cl - are similar, Cl doping did not result in substantial change in lattice parameter. All the elements were homogeneously distributed on a cleaved surface; the Sn/(S + Cl) ratio was 1.00. The crystal was an n-type degenerate semiconductor with a carrier concentration of ∼3 × 10 17 cm -3 . Hall mobility at 300 K was 252 cm 2 V -1 s -1 and reached 363 cm 2 V -1 s -1 at 142 K.

The influence of oxide on the electrochemical processes in K2NbF7-NaCl-KCl melts

DEFF Research Database (Denmark)

Lantelme, F.; Berghoute, Y.; Barner, Jens H. Von

1995-01-01

Transient electrochemical techniques showed that in NaCl-KCl melts the reduction of K2NbF7 occurs through atwo-step reaction Nb(V) --> Nb(IV) --> Nb. When oxide ions were introduced, cyclic voltammetry indicated that the wavescorresponding to reduction of the complex NbF72- progressively...

Separation of CsCl and SrCl_2 from a ternary CsCl-SrCl_2-LiCl via a zone refining process for waste salt minimization of pyroprocessing

International Nuclear Information System (INIS)

Shim, Moonsoo; Choi, Ho Gil; Yi, Kyung Woo; Hwang, Il Soon; Lee, Jong Hyeon

2016-01-01

The purification of LiCl salt mixture has traditionally been carried out by a melt crystallization process. To improve the throughput of zone refining, three heaters were installed in the zone refiner. The zone refining method was used to grow pure LiCl salt ingots from LiCl-CsCl-SrCl_2 salt mixture. The main investigated parameters were the heater speed and the number of passes. A change in the LiCl crystal grain size was observed according to the horizontal direction. From each zone refined salt ingot, samples were collected horizontally. To analyze the concentrations of Sr and Cs, an inductively coupled plasma optical emission spectrometer and inductively coupled plasma mass spectrometer were used, respectively. The experimental results show that Sr and Cs concentrations at the initial region of the ingot were low and reached their peak at the final freezing region of the salt ingot. Concentration results of zone refined salt were compared with theoretical results yielded by the proposed model to validate its predictions. The k_e_f_f of Sr and Cs were 0.13 and 0.11, respectively. The decontamination factors of Sr and Cs were 450 and 1650, respectively. - Highlights: • The LiCl-CsCl-SrCl_2 salt ingot was purified by zone refining technique to minimize waste salt. • The concentration distribution of Cs and Sr were analyzed by mass transfer equation. • The decontamination factors of Cs and Sr were 1600 and 450 respectively in case of 60% of recovery yield.

Early IGF-1 primes visual cortex maturation and accelerates developmental switch between NKCC1 and KCC2 chloride transporters in enriched animals.

Science.gov (United States)

Baroncelli, Laura; Cenni, Maria Cristina; Melani, Riccardo; Deidda, Gabriele; Landi, Silvia; Narducci, Roberta; Cancedda, Laura; Maffei, Lamberto; Berardi, Nicoletta

2017-02-01

Environmental enrichment (EE) has a remarkable impact on brain development. Continuous exposure to EE from birth determines a significant acceleration of visual system maturation both at retinal and cortical levels. A pre-weaning enriched experience is sufficient to trigger the accelerated maturation of the visual system, suggesting that factors affected by EE during the first days of life might prime visual circuits towards a faster development. The search for such factors is crucial not only to gain a better understanding of the molecular hierarchy of brain development but also to identify molecular pathways amenable to be targeted to correct atypical brain developmental trajectories. Here, we showed that IGF-1 levels are increased in the visual cortex of EE rats as early as P6 and this is a crucial event for setting in motion the developmental program induced by EE. Early intracerebroventricular (i.c.v.) infusion of IGF-1 in standard rats was sufficient to mimic the action of EE on visual acuity development, whereas blocking IGF-1 signaling by i.c.v. injections of the IGF-1 receptor antagonist JB1 prevented the deployment of EE effects. Early IGF-1 decreased the ratio between the expression of NKCC1 and KCC2 cation/chloride transporters, and the reversal potential for GABA A R-driven Cl - currents (E Cl ) was shifted toward more negative potentials, indicating that IGF-1 is a crucial factor in accelerating the maturation of GABAergic neurotransmission and promoting the developmental switch of GABA polarity from excitation to inhibition. In addition, early IGF-1 promoted a later occurring increase in its own expression, suggesting a priming effect of early IGF-1 in driving post-weaning cortical maturation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemical characterisation of CaCl2 deficient LiCl–KCl–CaCl2 eutectic melt and electro-deoxidation of solid UO2

International Nuclear Information System (INIS)

Sri Maha Vishnu, D.; Sanil, N.; Mohandas, K.S.; Nagarajan, K.

2016-01-01

The CaCl 2 deficient ternary eutectic melt LiCl–KCl–CaCl 2 (50.5: 44.2: 5.3 mol %) was electrochemically characterised by cyclic voltammetry and polarization techniques in the context of its probable use as the electrolyte in the electrochemical reduction of solid UO 2 to uranium metal. Tungsten (cathodic polarization) and graphite (anodic polarization) working electrodes were used in these studies carried out in the temperature range 623 K–923 K. The cathodic limit of the melt was observed to be set by the deposition of Ca 2+ ions followed by Li + ions on the tungsten electrode and the anodic limit by oxidation of chloride ions on the graphite electrode (chlorine evolution). The difference between the onset potential of deposition of Ca 2+ and Li + was found to be 0.241 V at a scan rate of 20 mV/s at 623 K and the difference decreased with increase in temperature and vanished at 923 K. Polarization measurements with stainless steel (SS) cathode and graphite anode at 673 K showed the possibility of low–energy reactions occurring on the UO 2 electrode in the melt. UO 2 pellets were cathodically polarized at 3.9 V for 25 h to test the feasibility of electro-reduction to uranium in the melt. The surface of the pellets was found reduced to U metal. - Highlights: • Electrochemically characterized LiCl–KCl–CaCl 2 (50.5: 44.2: 5.3 mol %) melt by CV, LSV and polarization techniques. • Ca 2+ deposits first on tungsten working electrode followed by Li + . Cl − discharges on graphite to liberate chlorine gas. • Surface of UO 2 pellet reduced to U in the melt with low carbon contamination of melt. • Slow reduction of UO 2 due to slow kinetics and low solubility of oxide ions in the low temperature melt.

?????????? ?????, ?????????? ??????????? ?? ?????????? ?????????? ????? ? ?????? ???????? ZnCl2 +NH4Cl

OpenAIRE

Kuntyi, Orest; Zozulya, Galyna

2010-01-01

Zinc cementation by magnesium from ZnCl2 + NH4Cl aqueous solutions has been investigated. The amount of magnesium has been established as 0.8?2.0 g per 1 g of conditioned zinc to obtain recovery degree ? 99 %. At low concentrations of Zn2+ ions (0.025?0.1 M ZnCl2) dispersed deposit is formed with nanoparticles of reduced metal; at high concentrations (0.25?0.5 M) coarse-crystalline and fern-shaped deposit is formed. ?????????? ?????????? ????? ??????? ? ?????? ???????? ZnCl2 + NH4Cl. ????????...

Genetic disorders of transporters/channels in the inner ear and their relation to the kidney.

NARCIS (Netherlands)

Peters, T.A.; Monnens, L.A.H.; Cremers, C.W.R.J.; Curfs, J.H.A.J.

2004-01-01

Inner ear physiology is reviewed with emphasis on features common to renal physiology. Genetic disorders in transporters/channels for chloride (ClC-K), bicarbonate (Cl(-)/HCO(3)(-) exchanger), protons (H(+)-ATPase), sodium (ENaC, NKKC1, NBC3, NHE3), potassium (KCNQ1/KCNE1, Kcc4), and water (AQP4) in

Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells

DEFF Research Database (Denmark)

Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna

2017-01-01

The thiazide-sensitive sodium chloride cotransporter NCC is important for maintaining serum sodium (Na(+)) and, indirectly, serum potassium (K(+)) levels. Functional studies on NCC have used cell lines with native NCC expression, transiently transfected nonpolarized cell lines, or Xenopus laevis...

Radiative transitions for the Cs2NaErCl6 elpasolite crystal. I.- Vibronic intensities for the emissions |(4115/2)Γk]≤| (4I13/2)Γl] in the Cs2NaErCl6

International Nuclear Information System (INIS)

Acevedo, R.; Escudero, M; Navarro, G; Meruane, T

2002-01-01

In this paper, we report explicit calculations for the spectral intensities of the seventy-five emissions |( 4 I 1372 )Γ k ]→ ( 4 I 15/2 )Γ l ] +v m ; m=3,4,6, where the irreducible representations labels are chosen as: (Γ k ; Γ l )=(Γ 6 ,2Γ 7 ,2Γ 8 ; Γ 6 , Γ 7 ,3Γ 8 , of the ErCl 3- 6 clusters in the Cs 2 NaErCl 6 crystal. The details of the spectrum suggest that in an energy range of about 400cm -1 , a substantial number of transitions [25 magnetic dipole (MD) and 75 vibronic electric dipole (VED) excitations] may be observed and also that a number of super positions of these transitions is most likely to occur. This experimental evidence is rather complicated to analyze and there is a need for more theoretical backup to gain understanding in both radiative and non-radiative processes in these materials. In this paper, we have taken a broader view of the intensity mechanisms associated with vibronically allowed electronic transitions and have decided to further test our current calculation models (VCF-LP) with reference to the |( 4 I 13/2 )Γ k ]→|( 4 I 15/2 )Γl]+v m , emissions for this crystal. It is interesting to realize that, although the intrinsic limitations of our models and methods to estimate spectral intensities, the final output (calculated oscillator strengths) indicate a fair and sensible agreement between our theoretical predictions and experimental data. As a further test of our vibronic intensity model, in a forthcoming paper, we will examine the rather unusual high intensity associated with the |( 4 S 3/ ) Γ l →|( 4 I 15/2 )Γ k ] emissions for this elpasolite (author)

A temperature dependence kinetics study of the reactions of Cl/2-P-3/2/ with O3, CH4, and H2O2

Science.gov (United States)

Watson, R.; Machado, G.; Fischer, S.; Davis, D. D.

1976-01-01

The temperature dependence of two chlorine atom reactions of considerable fundamental importance to stratospheric chemistry was studied using the technique of flash photolysis-resonance fluorescence. The reactions of interest were: (1) Cl + O3 yields ClO + O2 studied at 220-350 K, and (2) Cl + CH4 yields CH3 + HCl studied at 218-401 K. In addition, the reaction Cl + H2O2 yields HCl + HO2 was studied at 300 K. The corresponding rate constants are provided for the three reactions. The new rate data implies the need to revise downward by a factor of 2.4-3 the magnitude of the ozone perturbation due to the presence of ClO/x/ species in the stratosphere, predicted by earlier model calculations.

[Sodium Glucose Co-transporter Type 2 (SGLT2) Inhibitors in CKD].

Science.gov (United States)

Insalaco, Monica; Zanoli, Luca; Rastelli, Stefania; Lentini, Paolo; Rapisarda, Francesco; Fatuzzo, Pasquale; Castellino, Pietro; Granata, Antonio

2015-01-01

Among the new drugs used for the treatment of Diabetes Mellitus type 2, sodium-glucose cotransporter 2 (SGLT2) inhibitors represent a promising therapeutic option. Since their ability to lower glucose is proportional to GFR, their effect is reduced in patients with chronic kidney disease (CKD). The antidiabetic mechanism of these drugs is insulin-independent and, therefore, complimentary to that of others antihyperglicaemic agents. Moreover, SGLT2 inhibitors are able to reduce glomerular hyperfiltration, systemic and intraglomerular pressure and uric acid levels, with consequent beneficial effects on the progression of kidney disease in non diabetic patients as well. Only few studies have been performed to evaluate the effects of SGLT2 inhibitors in patients with CKD. Therefore, safety and efficacy of SGLT2 inhibitors should be better clarified in the setting of CKD. In this paper, we will review the use of SGLT2 inhibitors in diabetic patients, including those with CKD.

Separation of CsCl and SrCl{sub 2} from a ternary CsCl-SrCl{sub 2}-LiCl via a zone refining process for waste salt minimization of pyroprocessing

Energy Technology Data Exchange (ETDEWEB)

Shim, Moonsoo [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 (Korea, Republic of); Choi, Ho Gil; Yi, Kyung Woo; Hwang, Il Soon [Graduate School of Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Lee, Jong Hyeon, E-mail: jonglee@cnu.ac.kr [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 (Korea, Republic of); Graduate School of Department of Advanced Materials Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 (Korea, Republic of); Rapid Solidified Materials Research Center, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134 (Korea, Republic of)

2016-11-15

The purification of LiCl salt mixture has traditionally been carried out by a melt crystallization process. To improve the throughput of zone refining, three heaters were installed in the zone refiner. The zone refining method was used to grow pure LiCl salt ingots from LiCl-CsCl-SrCl{sub 2} salt mixture. The main investigated parameters were the heater speed and the number of passes. A change in the LiCl crystal grain size was observed according to the horizontal direction. From each zone refined salt ingot, samples were collected horizontally. To analyze the concentrations of Sr and Cs, an inductively coupled plasma optical emission spectrometer and inductively coupled plasma mass spectrometer were used, respectively. The experimental results show that Sr and Cs concentrations at the initial region of the ingot were low and reached their peak at the final freezing region of the salt ingot. Concentration results of zone refined salt were compared with theoretical results yielded by the proposed model to validate its predictions. The k{sub eff} of Sr and Cs were 0.13 and 0.11, respectively. The decontamination factors of Sr and Cs were 450 and 1650, respectively. - Highlights: • The LiCl-CsCl-SrCl{sub 2} salt ingot was purified by zone refining technique to minimize waste salt. • The concentration distribution of Cs and Sr were analyzed by mass transfer equation. • The decontamination factors of Cs and Sr were 1600 and 450 respectively in case of 60% of recovery yield.

Mechanistic study on the fluorination of K[B(CN)4] with ClF enabling the high yield and large scale synthesis of K[B(CF3)4] and K[(CF3)3BCN].

Science.gov (United States)

Bernhardt, Eduard; Finze, Maik; Willner, Helge

2011-10-17

The fluorination of K[B(CN)(4)] with ClF is studied by millimolar test reactions in aHF and CH(2)Cl(2) solution and by subsequent identification of intermediates such as B-CF═NCl, B-CF(2)-NCl(2), and B-CF(3) species as well as NCl(3) by (19)F, (11)B NMR, and Raman spectroscopy, respectively. At first one cyano group of K[B(CN)(4)] is converted fast into a CF(3) group, and with increasing fluorination the reaction becomes slower and several intermediates could be observed. On the basis of these results, a synthesis was developed for K[B(CF(3))(4)] on a 0.2 molar scale by treatment of K[B(CN)(4)] diluted in aHF with ClF. The course of the reactions was followed by (i) monitoring the vapor pressure inside the reactor, (ii) observing the heat dissipation during ClF uptake, and (iii) measuring the volume of the released nitrogen gas. Since the fluorination of the last cyano group proceeds very slowly, the selective synthesis of K[(CF(3))(3)BCN] on a 0.2 molar scale is possible, as well. The analysis of the mechanisms, thermodynamics, and kinetics of the fluorination reactions is supported by density functional theory (DFT) calculations.

Water transport by the Na+/glucose cotransporter under isotonic conditions

DEFF Research Database (Denmark)

Zeuthen, T; Meinild, A K; Klaerke, D A

1997-01-01

Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed ...... of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin.......Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed...... in Xenopus oocytes. We present a method which allows short-term exposures to sugar under voltage clamp conditions. We demonstrate that water is cotransported with the solutes despite no osmotic differences between the external and intracellular solutions. There is a fixed ratio of 195:1 between the number...

A mass spectrometric study of the neutral and ionic vapor components of ytterbium chlorides; formation enthalpies of YbCl2 and YbCl3 molecules, and YbCl3- and YbCl4- ions in the gas phase

International Nuclear Information System (INIS)

Kuznetsov, F.Yh.; Kudin, L.S.; Pogrebnoj, A.M.; Butman, M.F.; Burdukovskaya, G.G.

1997-01-01

Ionic and neutral components of saturated vapour over the ytterbium di-and trichloride is studied through the Knudsen effusive method with mass-spectromic registration of evaporated products within the temperature range of 1000-1300 K. It is found that ytterbium trichloride is subjected to thermal decomposition with formation of ytterbium dichloride and molecular chloride. Sublimation enthalpy and enthalpy of YbCl 2 and YbCl 3 molecules formation in a gaseous phase at 298 K, comprising 356±6, 293±8, -425±6 and -667±6 kJ/mole correspondingly, are determined with application of 2 and 3 thermodynamical laws. Enthalpies of YbCl 3 - and YbCl 4 - negative ions formation in a gaseous phase at 298 K equal to -895 and -1211±30 kJ/mole correspondingly are calculated by measured equilibrium constants ion-molecular reaction. 30 refs., 3 figs., 3 tabs

Measurements of 36Cl production rates from Cl, K, and Ca in concrete at the 500-MeV neutron irradiation facility of KENS

International Nuclear Information System (INIS)

Aze, T.; Fujimura, M.; Matsumura, H.; Masumoto, K.; Nakao, N.; Kawai, M.; Matsuzaki, H.; Nagai, H.

2005-01-01

In high-energy accelerator facilities, concrete components around beam lines are exposed to secondary neutrons having various energies during machine operation. The neutrons produce the various long half-life radionuclides, such as 3 H, 36 Cl, 60 Co, and 152 Eu, in the concrete. Most of the nuclides mainly produced by thermal neutron-capture reactions and their specific activities are important from the viewpoint of accelerator clearance. In previous work, the specific activities of the 36 Cl in the concretes at the various accelerator facilities have been measured and it was suggested that the 36 Cl in the concrete is useful as an indicator for thermal neutron fluence because of a characteristic of very long half life (301 kyr). However, in the concretes of the accelerator facilities over several hundreds of MeV, the 36 Cl are considerably produced by spallation from other concrete components, such as K and Ca, in addition to the thermal neutron capture of 35 Cl. The contribution of the 36 Cl productions from the spallation is unclear due to the lack of the cross sections for the neutron-induced reactions. In this work, therefore, we measured the 36 Cl production rates in concrete from Cl, K, and Ca targets in irradiation with secondary neutrons, which were produced by a bombardment of primary 500-MeV protons with W targets, at high-energy neutron-irradiation course of KENS. Samples of NaCl, K2CO 3 , and CaCO 3 were set into 7. irradiation spaces located on the depth raging from O to 320 cm from the concrete surface and irradiated for approximately one week. After the irradiation, separations of Cl from the samples were carried out radiochemically and the production rates of 36 Cl were determined by the AMS. The production rates from Cl, K, and Ca exponentially decreased with an increase of the depth from the concrete surface, and the profiles were very similar each other. Although the production rates from Cl were two orders higher than those from Ca in the same

Redox equilibrium of U4+/U3+ in molten NaCl-2CsCl by UV-Vis spectrophotometry and cyclic voltammetry

International Nuclear Information System (INIS)

Nagai, Takayuki; Uehara, Akihiro; Fujii, Toshiyuki; Shirai, Osamu; Yamana, Hajimu; Sato, Nobuaki

2005-01-01

In order to investigate the redox equilibrium of uranium ions in molten NaCl-2CsCl, UV-Vis absorption spectro-photometry measurements were performed for U 4+ and U 3+ in molten NaCl-2CsCl at 923 K under simultaneous electrolytic control of their ratio. Prominent absorption bands at 480 and 570 nm were assigned to U 3+ , and their molar absorptivities were determined to be 1,260±42 and 963±32 mol -1 ·l·cm -1 respectively. From the dependence of the rest potential of the melt on the spectrophotometrically determined ratio of [U 4+ ]/[U 3+ ], the standard redox potential of the couple U 4+ /U 3+ at 923 K was determined to be -1.481±0.004 V vs. Cl 2 /Cl - . Cyclic voltammetry measurements were carried out for the couple U 4+ /U 3+ , and the results agreed well with this standard redox potential value. By the results of cyclic voltammetry, a temperature dependence of the standard redox potential was found to be -2.094+6.639 x 10 -4 T (T=823-923K). (author)

No solid solution compounds in between the binaries. Syntheses and crystal structures of Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Reckeweg, Olaf; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

2018-04-01

The anion-mixed niobium tetrahalides Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2} were obtained by heating NbBr{sub 5} with NbCl{sub 5} and NbI{sub 5} with NbCl{sub 5}, respectively, in equimolar ratios with niobium metal in evacuated, torch-sealed silica ampoules at 720 K for 3 days. The orthorhombic title compounds form as very brittle black needles and were characterized by single-crystal X-ray diffraction [space group: Immm, Z=4; a=704.27(6), b=824.13(7), c=929.64(8) pm for Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and a=753.76(6), b=829.38(7) and c=983.41(8) pm for NbI{sub 2}Cl{sub 2}]. Surprisingly enough, these mixed-anionic halides are not isostructural with either NbCl{sub 4}, NbBr{sub 4} or NbI{sub 4}, but crystallize isotypically with TaI{sub 2}Cl{sub 2}, thus being examples for differential site occupancy stabilized materials. Structural features of other niobium(IV) halides are compiled and compared to those of Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2}. Except for NbF{sub 4}, they all exhibit chains of trans-edge connected [NbX{sub 6}]{sup 2-} octahedra, which allow Peierls distortions to form Nb-Nb single bonds. The packing of these chains differ, however, depending on the actual halide or mixed-halide combination.

Theoretical descriptions of novel triplet germylenes M1-Ge-M2-M3 (M1 = H, Li, Na, K; M2 = Be, Mg, Ca; M3 = H, F, Cl, Br).

Science.gov (United States)

Kassaee, Mohamad Zaman; Ashenagar, Samaneh

2018-02-06

In a quest to identify new ground-state triplet germylenes, the stabilities (singlet-triplet energy differences, ΔE S-T ) of 96 singlet (s) and triplet (t) M 1 -Ge-M 2 -M 3 species were compared and contrasted at the B3LYP/6-311++G**, QCISD(T)/6-311++G**, and CCSD(T)/6-311++G** levels of theory (M 1  = H, Li, Na, K; M 2  = Be, Mg, Ca; M 3  = H, F, Cl, Br). Interestingly, F-substituent triplet germylenes (M 3  = F) appear to be more stable and linear than the corresponding Cl- or Br-substituent triplet germylenes (M 3  = Cl or Br). Triplets with M 1  = K (i.e., the K-Ge-M 2 -M 3 series) seem to be more stable than the corresponding triplets with M 1  = H, Li, or Na. This can be attributed to the higher electropositivity of potassium. Triplet species with M 3  = Cl behave similarly to those with M 3  = Br. Conversely, triplets with M 3  = H show similar stabilities and linearities to those with M 3  = F. Singlet species of formulae K-Ge-Ca-Cl and K-Ge-Ca-Br form unexpected cyclic structures. Finally, the triplet germylenes M 1 -Ge-M 2 -M 3 become more stable as the electropositivities of the α-substituents (M 1 and M 2 ) and the electronegativity of the β-substituent (M 3 ) increase.

Fibrous nano-silica supported ruthenium (KCC-1/Ru): A sustainable catalyst for the hydrogenolysis of alkanes with good catalytic activity and lifetime

KAUST Repository

Fihri, Aziz

2012-07-06

We have shown that fibrous nanosilica (KCC-1) can serve as a suitable support for the synthesis of highly dispersed ruthenium (Ru) nanoparticles. The resulting KCC-1/Ru catalyst displayed superior activity for the hydrogenolysis of propane and ethane at atmospheric pressure and at low temperature. The high catalytic activity was due to the formation of Ru-nanoparticles with an active size range (1-4 nm) and the presence of hexagonal-shaped particles with several corners and sharp edges possessing reactive atoms with lowest coordination numbers. The catalyst was stable with an excellent lifetime and no sign of deactivation, even after eight days. This enhanced stability may be due to the fibrous nature of KCC-1 which restricts Ostwald ripening of Ru nanoparticles. © 2012 American Chemical Society.

Role of Na,K-ATPase α1 and α2 isoforms in the support of astrocyte glutamate uptake.

Directory of Open Access Journals (Sweden)

Nina B Illarionova

Full Text Available Glutamate released during neuronal activity is cleared from the synaptic space via the astrocytic glutamate/Na(+ co-transporters. This transport is driven by the transmembrane Na(+ gradient mediated by Na,K-ATPase. Astrocytes express two isoforms of the catalytic Na,K-ATPase α subunits; the ubiquitously expressed α1 subunit and the α2 subunit that has a more specific expression profile. In the brain α2 is predominantly expressed in astrocytes. The isoforms differ with regard to Na+ affinity, which is lower for α2. The relative roles of the α1 and α2 isoforms in astrocytes are not well understood. Here we present evidence that the presence of the α2 isoform may contribute to a more efficient restoration of glutamate triggered increases in intracellular sodium concentration [Na(+]i. Studies were performed on primary astrocytes derived from E17 rat striatum expressing Na,K-ATPase α1 and α2 and the glutamate/Na(+ co-transporter GLAST. Selective inhibition of α2 resulted in a modest increase of [Na(+]i accompanied by a disproportionately large decrease in uptake of aspartate, an indicator of glutamate uptake. To compare the capacity of α1 and α2 to handle increases in [Na(+]i triggered by glutamate, primary astrocytes overexpressing either α1 or α2 were used. Exposure to glutamate 200 µM caused a significantly larger increase in [Na(+]i in α1 than in α2 overexpressing cells, and as a consequence restoration of [Na(+]i, after glutamate exposure was discontinued, took longer time in α1 than in α2 overexpressing cells. Both α1 and α2 interacted with astrocyte glutamate/Na(+ co-transporters via the 1st intracellular loop.

Rate constant and mechanism of the reaction Cl + CFCl₂H → CFCl₂ + HCl over the temperature range 298-670 K in N₂ or N₂/O₂ diluent.

Science.gov (United States)

Kaiser, E W; Jawad, Khadija M

2014-05-08

The rate constant of the reaction Cl + CFCl2H (k1) has been measured relative to the established rate constant for the reaction Cl + CH4 (k2) at 760 Torr. The measurements were carried out in Pyrex reactors using a mixture of CFCl2H, CH4, and Cl2 in either N2 or N2/O2 diluent. Reactants and products were quantified by GC/FID analysis. Cl atoms were generated by irradiation of the mixture with 360 nm light to dissociate the Cl2 for temperatures up to ~550 K. At higher temperature, the Cl2 dissociated thermally, and no irradiation was used. Over the temperature range 298-670 K, k1 is consistently a factor of ~5 smaller than that of k2 with a nearly identical temperature dependence. The optimum non-Arrhenius rate constant is represented by the expression k1 = 1.14 × 10(-22) T(3.49) e(-241/T) cm(3) molecule(-1) s(-1) with an estimated uncertainty of ±15% including uncertainty in the reference reaction. CFCl3 formed from the reaction CFCl2 + Cl2 (k3) is the sole product in N2 diluent. In ~20% O2 at 298 K, the CFCl3 product is suppressed. The rate constant of reaction 3 was measured relative to that of reaction 4 [CFCl2 + O2 (k4)] giving the result k3/k4 = 0.0031 ± 0.0005 at 298 K. An earlier experiment by others observed C(O)FCl to be the major product of reaction channel 4 [formed via the sequence, CFCl2(O2) → CFCl2O → C(O)FCl + Cl]. Our current experiments verified that there is a Cl atom chain reaction in the presence of O2 as required by this mechanism.

An enzyme-linked immunosorbent assay (ELISA) for quantification of human collectin 11 (CL-11, CL-K1)

Science.gov (United States)

Selman, L.; Henriksen, M.L.; Brandt, J.; Palarasah, Y.; Waters, A.; Beales, P.L.; Holmskov, U.; Jørgensen, T.J.D.; Nielsen, C.; Skjodt, K.; Hansen, S.

2012-01-01

Collectin 11 (CL-11), also referred to as collectin kidney 1 (CL-K1), is a pattern recognition molecule that belongs to the collectin group of proteins involved in innate immunity. It interacts with glycoconjugates on pathogen surfaces and has been found in complex with mannose-binding lectin-associated serine protease 1 (MASP-1) and/or MASP-3 in circulation. Mutation in the CL-11 gene was recently associated with the developmental syndrome 3MC. In the present study, we established and thoroughly validated a sandwich enzyme-linked immunosorbent assay (ELISA) based on two different monoclonal antibodies. The assay is highly sensitive, specific and shows excellent quantitative characteristics such as reproducibility, dilution linearity and recovery (97.7–104%). The working range is 0.15–34 ng/ml. The CL-11 concentration in two CL-11-deficient individuals affected by the 3MC syndrome was determined to be below 2.1 ng/ml. We measured the mean serum CL-11 concentration to 284 ng/ml in 100 Danish blood donors, with a 95% confidence interval of 269–299 ng/ml. There was no significant difference in the CL-11 concentration measured in matched serum and plasma samples. Storage of samples and repeated freezing and thawing to a certain extent did not influence the ELISA. This ELISA offers a convenient and reliable method for studying CL-11 levels in relation to a variety of human diseases and syndromes. PMID:22301270

Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit

DEFF Research Database (Denmark)

Zeuthen, T; Meinild, A K; Loo, D D

2001-01-01

water transport was divided about equally between cotransport, osmosis across the SGLT1 and osmosis across the native oocyte membrane. 6. Coexpression of AQP1 with the SGLT1 increased the water permeability more than 10-fold and steady state isotonic transport was achieved after less than 2 s of sugar......1. In order to study its role in steady state water transport, the Na+-glucose cotransporter (SGLT1) was expressed in Xenopus laevis oocytes; both the human and the rabbit clones were tested. The transport activity was monitored as a clamp current and the flux of water followed optically...... as the change in oocyte volume. 2. SGLT1 has two modes of water transport. First, it acts as a molecular water pump: for each 2 Na+ and 1 sugar molecule 264 water molecules were cotransported in the human SGLT1 (hSGLT1), 424 for the rabbit SGLT1 (rSGLT1). Second, it acts as a water channel. 3. The cotransport...

Difference in 201TlCl accumulation mechanism in brain tumors. A comparison of their Na+-K+ ATPase activities

International Nuclear Information System (INIS)

Sugo, Nobuo; Kuroki, Takao; Nemoto, Masaaki; Mito, Toshiaki; Seiki, Yoshikatsu; Shibata, Iekado

2000-01-01

The accumulation levels of 201 TlCl and Na + -K + ATPase activity in tumor tissue were compared among glioblastoma, benign glioma and meningioma to study the difference in the mechanism of 201 TlCl accumulation. The subjects were 19 cases comprised of 6 glioblastoma, 2 oligodendroglioma, 1 fibrillary astrocytoma, 1 pilocytic astrocytoma and 9 meningioma. Preoperative 201 TlCl SPECT was performed in all the cases, and Thallium Index (TL index) was calculated by a ratio of 201 TlCl in the tumor area and the contralateral area. In addition, cell membrane was extracted from the tumor tissue collected intraoperatively to determine Na + -K + ATPase activity. No statistically significant difference in TL index was noted between the glioblastoma group (6.97±2.67) and the meningioma group (5.87±1.99). This fact showed that there was no difference in the accumulation level of 201 TlCl between the two groups. On the other hand, the glioblastoma group indicated a higher value of Na + -K + ATPase activity (49.13±43.76 μmole/hour/mg protein) than the meningioma group (7.73±13.84 μmol/hour/mg protein) (p + -K + ATPase activity in 201 TlCl accumulation in glioblastoma and the influences of other accumulation mechanism than Na + -K + ATPase activity such as the volume of intratumoral vascular bed in meningioma. (author)

Magnetism of CuCl{sub 2}·2D{sub 2}O and CuCl{sub 2}·2H{sub 2}O, and of CuBr{sub 2}·6H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

2017-07-15

Highlights: • CuCl{sub 2}·2D{sub 2}O is examined magnetically and compared with CuCl{sub 2}·2H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 2}·6H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 2}·6H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 2}·6H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 2}·2D{sub 2}O are studied and compared with those of CuCl{sub 2}·2H{sub 2}O. New CuBr{sub 2}·6H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 2}·6H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

Excitation function measurements of sup 4 sup 0 Ar(p,3n) sup 3 sup 8 K, sup 4 sup 0 Ar(p,2pn) sup 3 sup 8 Cl and sup 4 sup 0 Ar(p,2p) sup 3 sup 9 Cl reactions

CERN Document Server

Nagatsu, K; Suzuki, K

1999-01-01

For the production of sup 3 sup 8 K, excitation functions of the sup 4 sup 0 Ar(p,3n) sup 3 sup 8 K reaction and its accompanying reactions sup 4 sup 0 Ar(p,2pn) sup 3 sup 8 Cl, and sup 4 sup 0 Ar(p,2p) sup 3 sup 9 Cl were measured at the proton energy of 20.5-39.5 MeV to determine the optimum conditions of irradiation. Target cells containing argon gas were prepared using specially developed tools in an argon-replaced glove box. In the sup 4 sup 0 Ar(p,3n) sup 3 sup 8 K, sup 4 sup 0 Ar(p,2pn) sup 3 sup 8 Cl, and sup 4 sup 0 Ar(p,2p) sup 3 sup 9 Cl reactions, the maximum cross sections were 6.7+-0.7, 34+-3.3 and 11+-1.2mbarn at 37.6, 39.5 and 32.0 MeV, respectively, and the saturation thick target yields were calculated to be 560, 2200, and 1300 sup * MBq/mu A, respectively, at an incident energy of 39.5 MeV ( sup * integral yield above 21 MeV).

Thermodynamics of {l_brace}zNaCl+(1-z)Na{sub 2}SO{sub 4}{r_brace}(aq) from T=278.15 K to T=318.15 K, and representation with an extended ion-interaction (Pitzer) model

Energy Technology Data Exchange (ETDEWEB)

Rard, Joseph A. E-mail: rard1@llnl.gov; Clegg, Simon L.; Platford, Robert

2003-06-01

In 1968, R.F. Platford reported the results from extensive isopiestic vapor-pressure measurements for the {l_brace}zNaCl+(1-z)Na{sub 2}SO{sub 4}{r_brace}(aq) system at T=298.15 K, using NaCl(aq) as the isopiestic reference standard [R.F. Platford, J. Chem. Eng. Data 13 (1968) 46-48]. However, only derived quantities were reported, and the experimental isopiestic equilibrium molalities were not given. The complete set of original isopiestic molalities from that study is tabulated in the present report. In addition, published thermodynamic information for this system is reviewed and the isopiestic equilibrium molalities, electromotive force measurements for five different types of electrochemical cells, and enthalpies of mixing from these other studies are critically assessed and recalculated consistently. These combined results are used to evaluate at T=298.15 K the two mixing parameters of Pitzer's ion-interaction model, {sup S}{theta}(Cl,SO{sub 4})=(1.236{+-}0.032{sub 5}){center_dot}10{sup -2} kg{center_dot}mol{sup -1} and {psi}(Na,Cl,SO{sub 4})=(1.808{+-}0.086){center_dot}10{sup -3} kg{sup 2}{center_dot}mol{sup -2}, and their temperature derivatives {l_brace}{partial_derivative}{sup S}{theta}(Cl,SO{sub 4})/{partial_derivative}T{r_brace}{sub p}=(2.474{+-}0.460){center_dot}10{sup -5} kg{center_dot}mol{sup -1}{center_dot}K{sup -1} and {l_brace}{partial_derivative}{psi}(Na,Cl,SO{sub 4})/{partial_derivative}T{r_brace}{sub p}=-(6.228{+-}0.186){center_dot}10{sup -5} kg{sup 2}{center_dot}mol{sup -2}{center_dot}K{sup -1}. Also reported are parameters for an extended ion-interaction model for Na{sub 2}SO{sub 4}(aq), valid from T=(273.15 to 323.15) K, that were required for this mixed electrolyte solution analysis.

Study on MnCl_2/CaCl_2–NH_3 two-stage solid sorption freezing cycle for refrigerated trucks at low engine load in summer

International Nuclear Information System (INIS)

Gao, P.; Zhang, X.F.; Wang, L.W.; Wang, R.Z.; Li, D.P.; Liang, Z.W.; Cai, A.F.

2016-01-01

Graphical abstract: A MnCl_2/CaCl_2–NH_3 two-stage solid sorption freezing cycle driven by the engine exhaust gas is proposed for refrigerated trucks. - Highlights: • A two-stage adsorption freezing system is designed and constructed for the refrigerated truck. • Composite adsorbents of MnCl_2 and CaCl_2 with the matrix of ENG-TSA are developed. • The average refrigerating capacity of 2.2 kW in the adsorption process is obtained. • The chilled air outlet temperature of the evaporator is controlled at about −5 °C. • The COP is 0.13 when the heating and refrigerating temperatures are 230 °C and −5 °C. - Abstract: A novel MnCl_2/CaCl_2–NH_3 two-stage solid sorption freezing cycle is designed and established for the refrigerated truck with the rated power of 80 kW. The conventional sorption/desorption process and the resorption process are combined in the two-stage cycle. Theoretical analysis shows that such a cycle could adapt to the low heat source temperature and the high cooling temperature of the sorption beds very well, which is quite essential for the truck when the running speed and the load are low in summer. The expanded natural graphite treated with sulfuric acid (ENG-TSA) is chosen as the matrix, and composite adsorbents of MnCl_2/ENG-TSA and CaCl_2/ENG-TSA are developed. The hot air heated by the electric heater is used to simulate the engine exhaust gas to drive the system. When the hot air, the ambient air and the refrigerating temperature are 230 °C, 30 °C and −5 °C, respectively, the average refrigerating capacity is 2.2 kW in the sorption process. Correspondingly, the COP and SCP are 0.13 and 91.7 W/kg, respectively. The average refrigerating capacity of 1.1 kW in one cycle is gotten, which could meet the required refrigerating capacity of the light refrigerated truck at the low engine load engine in summer.

Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect.

Science.gov (United States)

Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A G

2016-01-01

This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

Directory of Open Access Journals (Sweden)

Sanjay Kalra

2016-01-01

Full Text Available This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2 inhibition: Calorie restriction mimicry (CRM and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

Separating NaCl and AlCl3·6H2O Crystals from Acidic Solution Assisted by the Non-Equilibrium Phase Diagram of AlCl3-NaCl-H2O(-HCl Salt-Water System at 353.15 K

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Huaigang Cheng

2017-08-01

Full Text Available Extracting AlCl3·6H2O from acid leaching solution through crystallization is one of the key processes to extracting aluminum from fly ash, coal gangue and other industrial solid wastes. However, the obtained products usually have low purity and a key problem is the lack of accurate data for phase equilibrium. This paper presented the non-equilibrium phase diagrams of AlCl3-NaCl-H2O (HCl salt-water systems under continuous heating and evaporation conditions, which were the main components of the acid leaching solution obtained through a sodium-assisted activation hydrochloric acid leaching process. The ternary system was of a simple eutonic type under different acidities. There were three crystalline regions; the crystalline regions of AlCl3·6H2O, NaCl and the mixture AlCl3·6H2O/NaCl, respectively. The phase diagram was used to optimize the crystallization process of AlCl3·6H2O and NaCl. A process was designed to evaporate and remove NaCl at the first stage of the evaporation process, and then continue to evaporate and crystallize AlCl3·6H2O after solid-liquid separation. The purities of the final salt products were 99.12% for NaCl and up to 97.35% for AlCl3·6H2O, respectively.

New compounds bearing [M(S_2O_7)_3]"2"- anions (M = Si, Ge, Sn): Syntheses and characterization of A_2[Si(S_2O_7)_3] (A = Na, K, Rb), A_2[Ge(S_2O_7)_3] (A = Li, Na, K, Rb, Cs), A_2[Sn(S_2O_7)_3] (A = Na, K), and the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 with cationic "1_∞[HgCl_2_/_2]"+ chains

International Nuclear Information System (INIS)

Logemann, Christian; Witt, Julia; Wickleder, Mathias S.; Gunzelmann, Daniel; Senker, Juergen

2012-01-01

The reaction of the group 14 tetrachlorides MCl_4 (M = Si, Ge, Sn) with oleum (65 % SO_3) at elevated temperatures led to the unique anionic complexes [M(S_2O_7)_3]"2"- that show the central M atoms in coordination of three chelating S_2O_7"2"- groups. The mean distances M-O within the complexes increase from 175 pm (M = Si) via 186 pm (M = Ge) up to 200 pm (M = Sn). The charge balance for the [M(S_2O_7)_3]"2"- anions is achieved by alkaline metal ions A"+ (A = Li, Na, K, Rb, Cs) which were implemented in the syntheses in form of their sulfates. The size of the A"+ ions, i.e. their coordination requirement causes the crystallographic differences in the crystal structures, while the structure of the complex [M(S_2O_7)_3]"2"- anions remains essentially unaffected. Furthermore, we were able to characterize the unique germanate Hg_2[Ge(S_2O_7)_3]Cl_2 which forms when HgCl_2 is added as a source for the counter cation. The Hg"2"+ and the Cl"- ions form infinite cationic chains according to "1_∞[HgCl_2_/_2]"+ which take care for the charge compensation. For selected examples of the compounds the thermal behavior has been monitored by means of thermal analyses and X-ray powder diffraction. For A being an alkaline metal the decomposition product is a mixture of the sulfates A_2SO_4 and the dioxides MO_2, whereas Hg_2[Ge(S_2O_7)_3]Cl_2 shows a more complicated decomposition. The tris-(disulfato)-silicate Na_2[Si(S_2O_7)_3] has additionally been examined by solid state "2"9Si and "2"3Na NMR spectroscopic measurements. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Electrochemical characterisation of CaCl{sub 2} deficient LiCl–KCl–CaCl{sub 2} eutectic melt and electro-deoxidation of solid UO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sri Maha Vishnu, D., E-mail: smvd2@cam.ac.uk; Sanil, N.; Mohandas, K.S.; Nagarajan, K.

2016-03-15

The CaCl{sub 2} deficient ternary eutectic melt LiCl–KCl–CaCl{sub 2} (50.5: 44.2: 5.3 mol %) was electrochemically characterised by cyclic voltammetry and polarization techniques in the context of its probable use as the electrolyte in the electrochemical reduction of solid UO{sub 2} to uranium metal. Tungsten (cathodic polarization) and graphite (anodic polarization) working electrodes were used in these studies carried out in the temperature range 623 K–923 K. The cathodic limit of the melt was observed to be set by the deposition of Ca{sup 2+} ions followed by Li{sup +} ions on the tungsten electrode and the anodic limit by oxidation of chloride ions on the graphite electrode (chlorine evolution). The difference between the onset potential of deposition of Ca{sup 2+} and Li{sup +} was found to be 0.241 V at a scan rate of 20 mV/s at 623 K and the difference decreased with increase in temperature and vanished at 923 K. Polarization measurements with stainless steel (SS) cathode and graphite anode at 673 K showed the possibility of low–energy reactions occurring on the UO{sub 2} electrode in the melt. UO{sub 2} pellets were cathodically polarized at 3.9 V for 25 h to test the feasibility of electro-reduction to uranium in the melt. The surface of the pellets was found reduced to U metal. - Highlights: • Electrochemically characterized LiCl–KCl–CaCl{sub 2} (50.5: 44.2: 5.3 mol %) melt by CV, LSV and polarization techniques. • Ca{sup 2+} deposits first on tungsten working electrode followed by Li{sup +}. Cl{sup −} discharges on graphite to liberate chlorine gas. • Surface of UO{sub 2} pellet reduced to U in the melt with low carbon contamination of melt. • Slow reduction of UO{sub 2} due to slow kinetics and low solubility of oxide ions in the low temperature melt.

Theory of the Chemla effect in molten (Li,K)Cl

International Nuclear Information System (INIS)

Tankeshwar, K.; Tosi, M.P.

1991-12-01

We treat ionic diffusion in liquid (Li,K)Cl mixtures by an approach originally due to Zwanzig, which evaluates the Green-Kubo time correlation formula by a jump-diffusion model involving an average vibrational frequency and an average residence time for each ionic species. These model parameters are calculated from the pair structure of the melt and from pair potentials. The diffusion coefficients of K + ions is found to overtake that of Li + ions with increasing content of KCl, in agreement with the experimental reversal of the electrical mobilities of the two cations discovered by Chemla. (author). 20 refs, 2 tabs

Cotransport of water and solutes in plant membranes: The molecular basis, and physiological functions

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Lars H. Wegner

2017-03-01

Full Text Available Current concepts of plant membrane transport are based on the assumption that water and solutes move across membranes via separate pathways. According to this view, coupling between the fluxes is more or less exclusively constituted via the osmotic force that solutes exert on water transport. This view is questioned here, and experimental evidence for a cotransport of water and solutes is reviewed. The overview starts with ion channels that provide pathways for both ion and water transport, as exemplified for maxi K+ channels from cytoplasmic droplets of Chara corallina. Aquaporins are usually considered to be selective for water (just allowing for slippage of some other small, neutral molecules. Recently, however, a “dual function” aquaporin has been characterized from Arabidopsis thaliana (AtPIP2.1 that translocates water and at the same time conducts cations, preferentially Na+. By analogy with mammalian physiology, other candidates for solute-water flux coupling are cation-chloride cotransporters of the CCC type, and transporters of sugars and amino acids. The last part is dedicated to possible physiological functions that could rely on solute-water cotransport. Among these are the generation of root pressure, refilling of embolized xylem vessels, fast turgor-driven movements of leaves, cell elongation (growth, osmoregulation and adjustment of buoyancy in marine algae. This review will hopefully initiate further research in the field.

THE EFFECTS OF DIFFERENT K2HP04 AND NaCl LEVELS ON THE WATER-HOLDING CAPACITY AND COOKING LOSS OF GOAT MEAT

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Mustafa Karakaya

1996-01-01

Full Text Available This research was conducted on the laboratory conditions. Different levels of K2HP04 (0.00%, 0.25%, 0.30% and NaCl (2.5%, 3.0% were applied on the goat meat and the pH, water holding capacity and cooking loss were observed. According to the results the effects of 0.25% K2HP04 addition was found statistically insignificant (p

Solid-liquid stable phase equilibria of the ternary systems MgCl2 + MgB6O10+ H2O AND MgSO4 + MgB6O10 + H2O at 308.15 K

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Lingzong Meng

2014-03-01

Full Text Available The solubilities and the relevant physicochemical properties of the ternary systems MgCl2 + MgB6O10 + H2O and MgSO4 + MgB6O10 + H2O at 308.15 K were investigated using an isothermal dissolution method. It was found that there is one invariant point, two univariant curves, and two crystallization regions of the systems. The systems belong to a simple co-saturated type, and neither double salts nor solid solutions were found. Based on the extended HW model and its temperature-dependent equations, the single-salt Pitzer parameters β(0, β(1, β(2 and CØ for MgCl2, MgSO4, and Mg(B6O7(OH6, the mixed ion-interaction parameters θCl,B6O10, θSO4,B6O10, ΨMg,Cl,B6O10, ΨMg,SO4,B6O10 of the systems at 308.15 K were fitted, In addition, the average equilibrium constants of the stable equilibrium solids at 308.15 K were obtained by a method using the activity product constant. Then the solubilities of the ternary systems are calculated. The calculated solubilities agree well with the experimental values.

CL-L1 and CL-K1 and other complement associated pattern recognition molecules in systemic lupus erythematosus

DEFF Research Database (Denmark)

Troldborg, Anne; Thiel, Steffen; Jensen, Lisbeth

2015-01-01

The objective of this study was to explore the involvement of collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1) and other pattern recognition molecules (PRMs) of the lectin pathway of the complement system in a cross-sectional cohort of systemic lupus erythematosus (SLE) patients...

Electrochemistry of oxygen-free curium compounds in fused NaCl-2CsCl eutectic

International Nuclear Information System (INIS)

Osipenko, A.; Maershin, A.; Smolenski, V.; Novoselova, A.; Kormilitsyn, M.; Bychkov, A.

2010-01-01

This work presents the electrochemical study of Cm(III) in fused NaCl-2CsCl eutectic in the temperature range 823-1023 K. Transient electrochemical techniques such as cyclic, differential pulse and square wave voltammetry, and chronopotentiometry have been used in order to investigate the reduction mechanism of curium ions up to the metal. The results obtained show that the reduction reaction takes place in a single step Cm(III)+3e-bar →Cm(0). The diffusion coefficient of [CmCl 6 ] 3- complex ions was determined by cyclic voltammetry at different temperatures by applying the Berzins-Delahay equation. The validity of the Arrhenius law was also verified and the activation energy for diffusion was found to be 44.46 kJ/mol. The apparent standard electrode potential of the redox couple Cm(III)/Cm(0) was found by chronopotentiometry at several temperatures. The thermodynamic properties of curium trichloride have also been calculated.

Sodium glucose co-transporter 2 (SGLT2) inhibitors: novel antidiabetic agents.

Science.gov (United States)

Washburn, William N

2012-05-01

Maintenance of glucose homeostasis in healthy individuals involves SGLT2 (sodium glucose co-transporter 2)-mediated recovery of glucose from the glomerular filtrate which otherwise would be excreted in urine. Clinical studies indicate that SGLT2 inhibitors provide an insulin-independent means to reduce the hyperglycemia that is the hallmark of type 2 diabetes mellitus (T2DM) with minimal risk of hypoglycemia. The pharmacophore common to the SGLT2 inhibitors currently in development is a diarylmethane C-glucoside which is discussed in this review. The focus is how this pharmacophore was further modified as inferred from the patents publishing from 2009 to 2011. The emphasis is on the strategy that each group employed to circumvent the constraints imposed by prior art and how the resulting SGLT2 potency and selectivity versus SGLT1 compared with that of the lead clinical compound dapagliflozin. SGLT2 inhibitors offer a new fundamentally different approach for treatment of diabetes. To date, the clinical results suggest that for non-renally impaired patients this class of inhibitors could be safely used at any stage of T2DM either alone or in combination with other marketed antidiabetic medications.

Mycoplasma orale infection affects K+ and Cl- currents in the HSG salivary gland cell line.

Science.gov (United States)

Izutsu, K T; Fatherazi, S; Belton, C M; Oda, D; Cartwright, F D; Kenny, G E

1996-06-01

The relations between K+ channel and Cl- channel currents and mycoplasma infection status were studied longitudinally in HSG cells, a human submandibular gland cell line. The K+ channel currents were disrupted by the occurrence of mycoplasma infection: muscarinic activation of K+ channels and K+ channel expression as estimated by ionomycin- or hypotonically induced K+ current responses were all decreased. Similar decreases in ionomycin- and hypotonically induced responses were observed for Cl- channels, but only the latter decrease was statistically significant. Also, Cl- currents could be elicited more frequently than K+ currents (63% of cases versus 0%) in infected cells when tested by exposure to hypotonic media, indicating that mycoplasma infection affects K+ channels relatively more than Cl- channels. These changes occurred in the originally infected cells, were ameliorated when the infection was cleared with sparfloxacin, and recurred when the cells were reinfected. Such changes would be expected to result in hyposecretion of salivary fluid if they occurred in vivo.

Kinetics of the Reactions of O((sup 3)P) and Cl((sup 2)P) with HBr and Br2

Science.gov (United States)

Nicovich, J. M.; Wine, P. H.

1997-01-01

A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of reactions (1)-(4) as a function of temperature. (1) O((sup 3)P) + Br2 yields BrO + Br((sup 2)P(sub 3/2)) at 255-350 K; (2) Cl((sup 2)P) + Br2 yields BrCl + Br((sup 2)P(sub 3/2)) at 298-401 K; (3) O((sup 3)P) + HBr yields OH + Br((sup 2)P(sub J)) at 250-402 K; (4) Cl((sup 2)P) + HBr yields HCl + Br((sup 2)P(sub J)) at 257-404 K. In all cases, the concentration of the excess reagent, i.e, HBr or Br2, was measured in situ in the slow flow system by UV-visible photometry. Heterogeneous dark reactions between XBr (X equals H or Br) and the photolytic precursors for Cl((sup 2)P) and O((sup 3)P) (Cl2 and O3, respectively) were avoided by injecting minimal amounts of precursor into the reaction mixture immediately upstream from the reaction zone. The following Arrhenius expressions summarize our results (errors are 2 sigma and represent precision only, units are cu cm/(molecule.s): k(sub 1) = (1.76 +/- 0.80) x 10(exp -11 exp[(40 +/- 100)/T]; k(sub 2) = (2.40 +/- 1.25) x 12(exp -10) exp[-(144 +/- 176)/T]; k(sub 3) = (5.11 +/- 2.82) x 10(exp -12) exp[-(1450 +/- 160)/T]; k(sub 4) = (2.25 +/- 0.56) x 10(exp -11) exp[-(400 +/- 80)/T]. The consistency (or lack thereof) of our results with those reported in previous kinetics and dynamics studies of reactions (1)-(4) is discussed.

Chloride sensing by WNK1 kinase involves inhibition of autophosphorylation

Science.gov (United States)

Piala, Alexander T.; Moon, Thomas M.; Akella, Radha; He, Haixia; Cobb, Melanie H.; Goldsmith, Elizabeth J.

2014-01-01

WNK1 [with no lysine (K)] is a serine-threonine kinase associated with a form of familial hypertension. WNK1 is at the top of a kinase cascade leading to phosphorylation of several cotransporters, in particular those transporting sodium, potassium, and chloride (NKCC), sodium and chloride (NCC), and potassium and chloride (KCC). The responsiveness of NKCC, NCC, and KCC to changes in extracellular chloride parallels their phosphorylation state, provoking the proposal that these transporters are controlled by a chloride-sensitive protein kinase. Here, we found that chloride stabilizes the inactive conformation of WNK1, preventing kinase autophosphorylation and activation. Crystallographic studies of inactive WNK1 in the presence of chloride revealed that chloride binds directly to the catalytic site, providing a basis for the unique position of the catalytic lysine. Mutagenesis of the chloride binding site rendered the kinase less sensitive to inhibition of autophosphorylation by chloride, validating the binding site. Thus, these data suggest that WNK1 functions as a chloride sensor through direct binding of a regulatory chloride ion to the active site, which inhibits autophosphorylation. PMID:24803536

Formation of new halogenothiocarbonylsulfenyl halides, XC(S)SY, through photochemical matrix reactions starting from CS2 and a dihalogen molecule XY (XY=Cl2, Br2, or BrCl).

Science.gov (United States)

Tobón, Yeny A; Romano, Rosana M; Védova, Carlos O Della; Downs, Anthony J

2007-05-28

Isolation of a dihalogen molecule XY (XY=Cl2, Br2, or BrCl) with CS2 in a solid Ar matrix at about 15 K leads, by broad-band UV-vis photolysis (2002, ClCS*, Cl*...SCS, CCl4, *CCl3, :CCl2, SCl2, SCBr2, CBr4, *CBr3, BrC(S)Cl, BrCCl3, and :CBrCl, the following new molecules have also been identified as products of the various photoreactions: syn-ClC(S)SCl, anti-ClC(S)SCl, syn-BrC(S)SBr, anti-BrC(S)SBr, syn-ClC(S)SBr, anti-ClC(S)SBr, syn-BrC(S)SCl, anti-BrC(S)SCl, ClC(S)S*, BrCS*, and Br*...SCS. The IR spectra of these hitherto unknown species have been interpreted with reference to the predictions of ab initio (HF and MP2) and density functional theory (DFT) calculations. The results are analyzed in relation to the reaction pathways accessed by matrix photolysis.

Simple preparations of Pd6Cl12, Pt6Cl12, and Qn[Pt2Cl8+n], n=1, 2 (Q=TBA+, PPN+) and structural characterization of [TBA][Pt2Cl9] and [PPN]2[Pt2Cl10].C7H8.

Science.gov (United States)

Dell'Amico, Daniela Belli; Calderazzo, Fausto; Marchetti, Fabio; Ramello, Stefano; Samaritani, Simona

2008-02-04

The hexanuclear Pd6Cl12, i.e., the crystal phase classified as beta-PdCl2, was obtained by reacting [TBA]2[Pd2Cl6] with AlCl3 (or FeCl3) in CH2Cl2. The action of AlCl3 on PtCl42-, followed by digestion of the resulting solid in 1,2-C2H4Cl2 (DCE), CHCl3, or benzene, produced Pt6Cl12.DCE, Pt6Cl12.CHCl3, or Pt6Cl12.C6H6, respectively. Treating [TBA]2[PtCl6] with a slight excess of AlCl3 afforded [TBA][Pt2Cl9], whose anion was established crystallographically to be constituted by two "PtCl6" octahedra sharing a face. Dehydration of H2PtCl6.nH2O with SOCl2 gave an amorphous compound closely analyzing as PtCl4, reactive with [Q]Cl in SOCl2 to yield [Q][Pt2Cl9] or [Q]2[Pt2Cl10], depending on the [Q]Cl/Pt molar ratio (Q=TBA+, PPN+). A single-crystal X-ray diffraction study has shown [PPN]2[Pt2Cl10].C7H8 to contain dinuclear anions formed by two edge-sharing PtCl6 octahedra.

CH_3Cl, CH_2Cl_2, CHCl_3, and CCl_4: Infrared spectra, radiative efficiencies, and global warming potentials

International Nuclear Information System (INIS)

Wallington, Timothy J.; Pivesso, Bruno Pasquini; Lira, Alane Moura; Anderson, James E.; Nielsen, Claus Jørgen; Andersen, Niels Højmark; Hodnebrog, Øivind

2016-01-01

Infrared spectra for the title compounds were measured experimentally in 700 Torr of air at 295 K and systematically modeled in B3LYP, M06-2X and MP2 calculations employing various basis sets. Calibrated infrared spectra over the wavenumber range 600–3500 cm"−"1 are reported and combined with literature data to provide spectra for use in experimental studies and radiative transfer calculations. Integrated absorption cross sections are (units of cm"−"1 molecule"−"1): CH_3Cl, 660–780 cm"−"1, (3.89±0.19)×10"−"1"8; CH_2Cl_2, 650–800 cm"−"1, (2.16±0.11)×10"−"1"7; CHCl_3, 720–810 cm"−"1, (4.08±0.20)×10"−"1"7; and CCl_4, 730–825 cm"−"1, (6.30±0.31)×10"−"1"7. CH_3Cl, CH_2Cl_2, CHCl_3, and CCl_4 have radiative efficiencies of 0.004, 0.028, 0.070, and 0.174 W m"−"2 ppb"−"1 and global warming potentials (100 year horizon) of 5, 8, 15, and 1775, respectively. Quantum chemistry calculations generally predict larger band intensities than the experimental values. The best agreement with experiments is obtained in MP2(Full) calculations employing basis sets of at least triple-zeta quality augmented by diffuse functions. The B3LYP functional is found ill-suited for calculating vibrational frequencies and infrared intensities of halocarbons. - Highlights: • Infrared spectra reported for CH_3Cl, CH_2Cl_2, CHCl_3, and CCl_4. • REs of CH_3Cl, CH_2Cl_2, CHCl_3, and CCl_4 are 0.004, 0.028, 0.070, and 0.174 W m"−"2 ppb"−"1, respectively. • GWPs of CH_3Cl, CH_2Cl_2, CHCl_3, and CCl_4 are 5, 8, 15, and 1775, respectively.

Renal Dysfunction Induced by Kidney-Specific Gene Deletion of Hsd11b2 as a Primary Cause of Salt-Dependent Hypertension.

Science.gov (United States)

Ueda, Kohei; Nishimoto, Mitsuhiro; Hirohama, Daigoro; Ayuzawa, Nobuhiro; Kawarazaki, Wakako; Watanabe, Atsushi; Shimosawa, Tatsuo; Loffing, Johannes; Zhang, Ming-Zhi; Marumo, Takeshi; Fujita, Toshiro

2017-07-01

Genome-wide analysis of renal sodium-transporting system has identified specific variations of Mendelian hypertensive disorders, including HSD11B2 gene variants in apparent mineralocorticoid excess. However, these genetic variations in extrarenal tissue can be involved in developing hypertension, as demonstrated in former studies using global and brain-specific Hsd11b2 knockout rodents. To re-examine the importance of renal dysfunction on developing hypertension, we generated kidney-specific Hsd11b2 knockout mice. The knockout mice exhibited systemic hypertension, which was abolished by reducing salt intake, suggesting its salt-dependency. In addition, we detected an increase in renal membrane expressions of cleaved epithelial sodium channel-α and T53-phosphorylated Na + -Cl - cotransporter in the knockout mice. Acute intraperitoneal administration of amiloride-induced natriuresis and increased urinary sodium/potassium ratio more in the knockout mice compared with those in the wild-type control mice. Chronic administration of amiloride and high-KCl diet significantly decreased mean blood pressure in the knockout mice, which was accompanied with the correction of hypokalemia and the resultant decrease in Na + -Cl - cotransporter phosphorylation. Accordingly, a Na + -Cl - cotransporter blocker hydrochlorothiazide significantly decreased mean blood pressure in the knockout mice. Chronic administration of mineralocorticoid receptor antagonist spironolactone significantly decreased mean blood pressure of the knockout mice along with downregulation of cleaved epithelial sodium channel-α and phosphorylated Na + -Cl - cotransporter expression in the knockout kidney. Our data suggest that kidney-specific deficiency of 11β-HSD2 leads to salt-dependent hypertension, which is attributed to mineralocorticoid receptor-epithelial sodium channel-Na + -Cl - cotransporter activation in the kidney, and provides evidence that renal dysfunction is essential for developing the

Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes

KAUST Repository

Qureshi, Ziyauddin; Sarawade, Pradip; Albert, Matthias; D'Elia, Valerio; Hedhili, Mohamed Nejib; Kö hler, Klaus; Basset, Jean-Marie

2015-01-01

An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes

KAUST Repository

Qureshi, Ziyauddin

2015-01-09

An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

Theoretical study of the superhyperfine parameters for Cu{sup 2+} in K{sub 2}PdX{sub 4} (X = Cl, Br)

Energy Technology Data Exchange (ETDEWEB)

Wei, L. H.; Wu, S. Y., E-mail: shaoyi_wu@163.com; Zhang, Z. H.; Wang, X. F.; Hu, Y. X. [University of Electronic Science and Technology of China, Department of Applied Physics (China)

2008-01-15

The superhyperfine parameters T{sub j} (j = x, y, z) for Cu{sup 2+} in the square-planar K{sub 2}PdX{sub 4} (X = Cl, Br) are theoretically studied from the perturbation formulas of these parameters for an octahedral 3d{sup 9} cluster, by considering both the contributions from the crystal-field and charge-transfer mechanisms. The related molecular orbital coefficients are determined from the cluster approach in a uniform way. Based on one adjustable proportional factor {rho} for the orbital admixture coefficients, the calculated results of present work show reasonable agreement with the observed values.

Quadruple-layered perovskite (CuCl)Ca2NaNb4O13

International Nuclear Information System (INIS)

Kitada, A.; Tsujimoto, Y.; Yamamoto, T.; Kobayashi, Y.; Narumi, Y.; Kindo, K.; Aczel, A.A.; Luke, G.M.; Uemura, Y.J.; Kiuchi, Y.; Ueda, Y.; Yoshimura, K.; Ajiro, Y.; Kageyama, H.

2012-01-01

We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca 2 NaNb 4 O 13 . Through a topotactic ion-exchange reaction with CuCl 2 , the precursor RbCa 2 NaNb 4 O 13 presumably having an incoherent octahederal tliting changes into (CuCl)Ca 2 NaNb 4 O 13 with a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73232(5) Å, c=39.2156(4) Å). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl 4 O 2 octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov′s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca 2 NaNb 4 O 13 synthesized through a topotactic ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: ► (CuCl)Ca 2 NaNb 4 O 13 was prepared by ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . ► Compound has a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73 Å, c=39.21 Å). ► Such a well-defined superstructure was not observed in the precursor compound. ► Aleksandrov′s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). ► Magnetic studies revealed the absence of magnetic order down to 2 K.

Partitioning of K, Cl, S and P during combustion of poplar and brassica energy crops

DEFF Research Database (Denmark)

Díaz-Ramírez, Maryori; Jappe Frandsen, Flemming; Glarborg, Peter

2014-01-01

K-, Cl-, S- and P-release from a herbaceous (brassica) and a short rotation coppice (poplar) cultivated in the Mediterranean region, have been investigated under combustion conditions [500-1100 °C]. Contrary to brassica, Cl- and S-release from poplar were substantial for all temperatures tested....... Low-temperature [500-700 °C] Cl-release from the high-Cl brassica appeared to be primarily limited by the fuel chemical composition and secondarily by interactions of the ash-forming elements with the fuel organic matrix. Below 700 °C, Cl-release was nearly 50%, whereas complete dechlorination...... resulted around 800 °C. S-release from brassica was up to 40% at low temperature. Above 1000 °C, additional S-release was observed presumably by sulfate dissociation. K-release was linked to Cl-release around 700 °C and, gradually increased afterwards. At 1100 °C, nearly 60% of K in poplar was retained...

Synopsis of the 48 annual meeting of the Lake Cumberland Biological Transport Group and the second biannual meeting of the Pendrin Consortium.

Science.gov (United States)

Dossena, Silvia; Nofziger, Charity; Morabito, Rossana; Adragna, Norma C; Paulmichl, Markus

2013-01-01

Ion transporters are the molecular basis for ion homeostasis of the cell and the whole organism. The anion exchanger pendrin is only one of a number of examples where a complete or partial loss of function and/or deregulation of expression of ion transporters may lead or contribute to pathological conditions in humans. A complete understanding of the function of ion transporters in health and disease may pave the way for the identification of new and focused therapeutic approaches. Exchange of knowledge and connectivity between the experts in the feld of transport physiology is essential in facing these challenging tasks. The Lake Cumberland Biological Transport Group and the Pendrin Consortium are examples of scientific forums where investigators combine their efforts towards a better understanding of molecular pathophysiology of ion transport. This issue discusses the versatility of ion transporters involved in the regulation of cellular volume and other functions, such as the solute carrier (SLC) 12A gene family members SLC12A4-7, encoding the Na(+)-independent cation-chloride cotransporters commonly known as the K(+)-Cl(-) cotransporters KCC1-4, and the betaine/γ-aminobutyric acid transport system (BGT1, SLC6A12), just to name a few. The issue further addresses the pathophysiology of intestinal and respiratory epithelia and related therapeutic tools and techniques to investigate interactions between proteins and proteins and small compounds. Finally, the current knowledge and new findings on the expression, regulation and function of pendrin (SLC26A4) in the inner ear, kidney, airways and blood platelets are presented. © 2014 S. Karger AG, Basel.

Synopsis of the 48th Annual Meeting of the Lake Cumberland Biological Transport Group and the Second Biannual Meeting of the Pendrin Consortium

Directory of Open Access Journals (Sweden)

Silvia Dossena

2013-12-01

Full Text Available Ion transporters are the molecular basis for ion homeostasis of the cell and the whole organism. The anion exchanger pendrin is only one of a number of examples where a complete or partial loss of function and/or deregulation of expression of ion transporters may lead or contribute to pathological conditions in humans. A complete understanding of the function of ion transporters in health and disease may pave the way for the identification of new and focused therapeutic approaches. Exchange of knowledge and connectivity between the experts in the feld of transport physiology is essential in facing these challenging tasks. The Lake Cumberland Biological Transport Group and the Pendrin Consortium are examples of scientific forums where investigators combine their efforts towards a better understanding of molecular pathophysiology of ion transport. This issue discusses the versatility of ion transporters involved in the regulation of cellular volume and other functions, such as the solute carrier (SLC 12A gene family members SLC12A4-7, encoding the Na+-independent cation-chloride cotransporters commonly known as the K+-Cl- cotransporters KCC1-4, and the betaine/γ-aminobutyric acid transport system (BGT1, SLC6A12, just to name a few. The issue further addresses the pathophysiology of intestinal and respiratory epithelia and related therapeutic tools and techniques to investigate interactions between proteins and proteins and small compounds. Finally, the current knowledge and new findings on the expression, regulation and function of pendrin (SLC26A4 in the inner ear, kidney, airways and blood platelets are presented.

Cortisol regulation of ion transporter mRNA in Atlantic salmon gill and the effect of salinity on the signaling pathway

DEFF Research Database (Denmark)

Kiilerich, Pia; Kristiansen, Karsten; Madsen, Steffen S

2007-01-01

Based on real-time RT-PCR, analysis of transcripts of selected ion-regulatory proteins (Na(+), K(+)-ATPase alpha1a and alpha1b subunit, Na(+), K(+), 2Cl(-) cotransporter, cystic fibrosis transmembrane conductance regulator (CFTR), and H(+)-ATPase B-subunit), the regulatory role of cortisol and th...

Abstracts of Papers Presented at the Annual Meeting of the Society of General Physiologists Held at Woods Hole, Massachusetts on 10-13 September 1992.

Science.gov (United States)

1992-09-13

Qualitative Alteration of K-Cl Cotransport in Red Blood Cells with Hemoglobin S NORMA C. ADRAGNA and PETER K. LAUF, Departments of Pharmacology & Toxicology and...Adair, B. D.. 2 Brant. S. R.. 107. 122, 138 Adragna . N. C.. 139 Breituieser. (G. E., 150 Agre, P.. 127 Brot-Liroche. E., 147 Aitnizo. M.. 43 Browning, K

Sodium Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus : Cardiovascular and Kidney Effects, Potential Mechanisms, and Clinical Applications

NARCIS (Netherlands)

Heerspink, Hiddo J. L.; Perkins, Bruce A.; Fitchett, David H.; Husain, Mansoor; Cherney, David Z. I.

2016-01-01

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, including empagliflozin, dapagliflozin, and canagliflozin, are now widely approved antihyperglycemic therapies. Because of their unique glycosuric mechanism, SGLT2 inhibitors also reduce weight. Perhaps more important are the osmotic diuretic and

Reactions UF4 - ClO2F and UF5 - ClO2F

International Nuclear Information System (INIS)

Benoit, Raymond; Besnard, Ginette; Hartmanshenn, Olivier; Luce, Michel; Mougin, Jacques; Pelissie, Jean

1970-02-01

The study of the reaction UF 4 - ClO 2 F between 0 deg. and 100 deg. C, by various techniques (micro-sublimation, isopiestic method, IR and UV spectrography, thermogravimetry and X-ray diffraction) shows that intermediate steps are possible before the production of UF 5 . The whole reaction may be schematised by two equations: (1) n UF 4 + ClO 2 F → n UF x + ClO 2 (4 4 + ClO 2 F → UF x + 1/2 Cl 2 + O 2 . The more the temperature rises, the more the second equation becomes experimentally verified. The reaction at 0 deg. C between UF 5 and ClO 2 F may be represented by: UF 5 + ClO 2 F → UF 6 ClO 2 . The reactions: UF 5 + ClO 2 F → UF 6 + ClO 2 , UF 5 + ClO 2 F → UF 6 + 1/2 Cl 2 + O 2 are verified, the first and the second at 25 deg. C., the second from 50 deg. to 150 deg. C. From the results of AGRON it is possible to predict the residual solids before complete volatilization as UF 6 . The IR spectra of ClO 2 F adsorbed on UF 4 and UF x at 60 deg. C have been compared with those of gaseous ClO 2 F and UF 6 adsorbed on UF 4 . (authors) [fr

Cold white light generation through the simultaneous emission from Ce{sup 3+}, Dy{sup 3+} and Mn{sup 2+} in 90Al{sub 2}O{sub 3}{center_dot}2CeCl{sub 3}{center_dot}3DyCl{sub 3}{center_dot}5MnCl{sub 2} thin film

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, W. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, Mexico, D.F. 09340 (Mexico); Alvarez, E. [Departamento de Fisica, Universidad de Sonora (UNISON), Boulevard Luis Encinas y Rosales s/n, Hermosillo, Sonora 83000 (Mexico); Martinez-Martinez, R.; Yescas-Mendoza, E. [Instituto de Fisica y Matematicas, Universidad Tecnologica de la Mixteca, Carretera a Acatlima Km. 2.5, Huajuapan de Leon, Oaxaca 69000 (Mexico); Camarillo, I. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, Mexico, D.F. 09340 (Mexico); Caldino, U., E-mail: cald@xanum.uam.mx [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, Mexico, D.F. 09340 (Mexico)

2012-08-15

The photoluminescence of a CeCl{sub 3}, DyCl{sub 3} and MnCl{sub 2} doped aluminum oxide film deposited by ultrasonic spray pyrolysis was characterized by excitation, emission and decay time spectroscopy. A nonradiative energy transfer from Ce{sup 3+} to Dy{sup 3+} and Mn{sup 2+} is observed upon UV excitation at 278 nm (peak emission wavelength of AlGaN-based LEDs). Such energy transfer leads to a simultaneous emission of these ions in the blue, green, yellow and red regions, resulting in white light emission with CIE1931 chromaticity coordinates, x=0.34 and y=0.23, which correspond to cold white light with a color temperature of 4900 K. - Highlights: Black-Right-Pointing-Pointer 90Al{sub 2}O{sub 3}{center_dot}2CeCl{sub 3}{center_dot}3DyCl{sub 3}{center_dot}5MnCl{sub 2} thin film (AOCDM) could be prepared by spray pyrolysis. Black-Right-Pointing-Pointer Non-radiative energy transfer from Ce{sup 3+} to Dy{sup 3+} and Mn{sup 2+} takes place in AOCDM. Black-Right-Pointing-Pointer AOCDM (pumped with 278 nm-UV light) can generate 4900 K cold white light.

Determination of Cl, K, and Na in the blood serum of healthy elderly in the city of Sao Paulo, SP; Determinacao de Cl, K e Na em soro sanguineo de idosos saudaveis da cidade de Sao Paulo

Energy Technology Data Exchange (ETDEWEB)

Araujo, Nathalia Souza de; Saiki, Mitiko, E-mail: natsouzaraujo@yahoo.com.b, E-mail: mitiko@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2009-07-01

This work determined the blood serum concentration of Cl, K, and Na from a healthy elderly population of the city of Sao Paulo, Sao Paulo, Brazil viewing the comparison with reference values used in clinical laboratories. For collecting these samples the present work were approved by the Ethic Committee of the FMUSP and IPEN-CNEN/SP. The quality of the analytical results were evaluated by the analysis of the reference material certification NIST 1577b Bovine Liver. The results presented good accuracy and precision due to the fact that they presented relative errors less than 5.2 % and standard deviation less than 8.6 %. The average concentrations (mmol L{sup -1}) of Cl in the analysed serum were 99.1; the K were 3.9 and the Na were 136.9. The obtained data allows the to conclude that the mostly of the elderly presented Cl, K and Na concentrations in the range of reference values used in the clinical laboratories

Reactive quenching of two-photon excited xenon atoms by Cl2

International Nuclear Information System (INIS)

Bruce, M.R.; Layne, W.B.; Meyer, E.; Keto, J.W.

1987-01-01

Total binary and tertiary quench rates have been measured for the reaction Xe (5p 5 6p) + Cl 2 at thermal temperatures. Xenon atoms are excited by state-selective, two-photon absorption with a uv laser. The time dependent fluorescence from the excited atom in the IR and from XeCl* (B) product near 308 nm have been measured with subnanosecond time resolution. The decay rates are measured as a function of Cl 2 pressure to 20 Torr and Xe pressure to 400 Torr. The measured reaction rates (k 2 ∼ 10 -9 cm 3 sec -1 ) are consistent with a harpoon model described in a separate paper. We also measure large termolecular reaction rates for collisions with xenon atoms (k 3 ∼ 10 -28 cm 6 sec -1 ). Total product fluorescence has been examined using a gated optical multichannel analyzer. We measure unit branching fractions for high vibrational levels of XeCl* (B) with very little C state fluorescence observed. The measured termolecular rates suggest similar processes will dominate at the high buffer-gas pressures used in XeCl lasers. The effect of these large reactive cross sections for neutral xenon atoms on models of the XeCl laser will be discussed

Metaplasticity within the spinal cord: Evidence brain-derived neurotrophic factor (BDNF), tumor necrosis factor (TNF), and alterations in GABA function (ionic plasticity) modulate pain and the capacity to learn.

Science.gov (United States)

Grau, James W; Huang, Yung-Jen

2018-04-07

Evidence is reviewed that behavioral training and neural injury can engage metaplastic processes that regulate adaptive potential. This issue is explored within a model system that examines how training affects the capacity to learn within the lower (lumbosacral) spinal cord. Response-contingent (controllable) stimulation applied caudal to a spinal transection induces a behavioral modification indicative of learning. This behavioral change is not observed in animals that receive stimulation in an uncontrollable manner. Exposure to uncontrollable stimulation also engages a process that disables spinal learning for 24-48 h. Controllable stimulation has the opposite effect; it engages a process that enables learning and prevents/reverses the learning deficit induced by uncontrollable stimulation. These observations suggest that a learning episode can impact the capacity to learn in future situations, providing an example of behavioral metaplasticity. The protective/restorative effect of controllable stimulation has been linked to an up-regulation of brain-derived neurotrophic factor (BDNF). The disruption of learning has been linked to the sensitization of pain (nociceptive) circuits, which is enabled by a reduction in GABA-dependent inhibition. After spinal cord injury (SCI), the co-transporter (KCC2) that regulates the outward flow of Cl - is down-regulated. This causes the intracellular concentration of Cl - to increase, reducing (and potentially reversing) the inward flow of Cl - through the GABA-A receptor. The shift in GABA function (ionic plasticity) increases neural excitability caudal to injury and sets the stage for nociceptive sensitization. The injury-induced shift in KCC2 is related to the loss of descending serotonergic (5HT) fibers that regulate plasticity within the spinal cord dorsal horn through the 5HT-1A receptor. Evidence is presented that these alterations in spinal plasticity impact pain in a brain-dependent task (place conditioning). The

Kinetics and Mechanism of the Gas-Phase Reaction of Selected Carbonyls with Cl Atoms between 250 and 340 K

Science.gov (United States)

Hasson, A. S.; Algrim, L.; Abdelhamid, A.; Tyndall, G. S.; Orlando, J. J.

2013-12-01

Carbonyls are important products from the gas phase degradation of most volatile organic compounds. Their atmospheric reactions therefore have a significant impact on atmospheric composition, particularly in aged air masses. While the reactions of short-chain linear carbonyls are well understood, the chemistry of larger (> C6) and branched carbonyl is more uncertain. To provide insight into these reactions, the reactions of three carbonyls (methyl isopropyl ketone, MIK; di-isopropyl ketone, DIK; and diethyl ketone, DEK) with chlorine atoms were investigated between 250 and 340 K and 1 atm in the presence and absence of NOx and an HO2 source (methanol). Experiments were performed in a photochemical reactor using a combination of long-path Fourier transform infra-red spectroscopy, proton transfer reaction mass spectrometry and gas chromatography with flame ionization detection. The kinetics were studied using the relative rate technique with butanone and isopropanol as the reference compounds. The Arrhenius expression for the three rate coefficients was determined to be k(DEK+Cl) = 3.87 x 10-11e(2 × 7 kJ/mol)/RT cm3 molecules-1 s-1 , k(MIPK+Cl) = 7.20 x 10-11e(0.2× 8 kJ/mol)/RT cm3 molecules-1 s-1 , and k(DIPK+Cl) = 3.33 x 10-10e(-3× 8 kJ/mol)/RT cm3 molecules-1 s-1 . Measured reaction products accounted for 38-72 % of the reacted carbon and were consistent with strong deactivation of the carbon atom adjacent to the carbonyl group with respect to H-atom abstraction by Cl atoms. The product distributions also provide insight into radical recycling from the organic peroxy + HO2 reaction, and the relative rates of isomerization, fragmentation and reaction with O2 for carbonyl-containing alkoxy radicals. Implications of these results will be discussed.

Polymorphism in 2-X-adamantane derivatives (X = Cl, Br).

Science.gov (United States)

Negrier, Philippe; Barrio, María; Tamarit, Josep Ll; Mondieig, Denise

2014-08-14

The polymorphism of two 2-X-adamantane derivatives, X = Cl, X = Br, has been studied by X-ray powder diffraction and normal- and high-pressure (up to 300 MPa) differential scanning calorimetry. 2-Br-adamantane displays a low-temperature orthorhombic phase (space group P212121, Z = 4) and a high-temperature plastic phase (Fm3̅m, Z = 4) from 277.9 ± 1.0 K to the melting point at 413.4 ± 1.0 K. 2-Cl-adamantane presents a richer polymorphic behavior through the temperature range studied. At low temperature it displays a triclinic phase (P1̅, Z = 2), which transforms to a monoclinic phase (C2/c, Z = 8) at 224.4 ± 1.0 K, both phases being ordered. Two high-temperature orientationally disordered are found for this compound, one hexagonal (P63/mcm, Z = 6) at ca. 241 K and the highest one, cubic (Fm3̅m, Z = 4), being stable from 244 ± 1.0 K up to the melting point at 467.5 ± 1.0 K. No additional phase appears due to the increase in pressure within the studied range. The intermolecular interactions are found to be weak, especially for the 2-Br-adamantane compound for which the Br···Br as well as C-Br···H distances are larger than the addition of the van der Waals radii, thus confirming the availability of this compound for building up diamondoid blocks.

Thermal gravimetric analysis of the CsCuCl3, Cs2CuCl4 and Cs2CuCl4x2H2O crystals

International Nuclear Information System (INIS)

Soboleva, L.V.; Vasil'eva, M.G.

1977-01-01

The thermal characteristics of crystals of Cs 2 CuCl 4 , Cs 2 CuCl 4 x2H 2 O, and CsCuCl 3 were investigated thermogravimetrically. The derivatogram of the Cs 2 CuCl 4 crystal is characterized by the presence of a single endothermal effect at 505 deg C. The derivatogram of the Cs 2 CuCl 4 x2H 2 O crystal contains three endothermal effects: at 40, 135, and 480 deg C. The derivatogram of the CsCuCl 3 crystal shows the presence of two endothermal effects at 142 and 455 deg C. The thermogravimetric data on Cs 2 CuCl 4 and CsCuCl 3 crystals reveal crystal decomposition on melting; hence, these crystals cannot be grown from melts

Microbial Fuel Cell Inoculated with Ochrobactrum Tritici KCC210 for Chromium (VI) Measurement in Electroplating Wastewater

Science.gov (United States)

Kuo, Jongtar; Kuo, Juiling; Cheng, Chiuyu; Chung, Yingchien

2018-01-01

Many methods/techniques have been developed for Cr(VI) measurement, but they are often conducted offsite or/and cannot provide real-time for Cr(VI) monitoring. A microbial fuel cell (MFC) is a self-sustaining device and has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Ochrobactrum tritici KCC210, a facultatively anaerobic, Cr(VI)-reducing, and exoelectrogenic bacterium, was isolated and inoculated into the MFC to evaluate its feasibility as a Cr(VI) biosensor. The results indicated that O. tritici KCC210 exhibited high adaptability to pH, and temperature under anaerobic conditions. The maximum power density of the MFC biosensor was 17.5±0.9 mW/m2 at 2,000 Ω. A good linear relationship was observed between the Cr(VI) concentration (10-80 mg/L) and voltage output. The stable performance of the MFC biosensor indicated its potential as a reliable biosensor system. Moreover, the developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater generated from different electroplating units within 15 min with low deviations (-1.8% to 7.8%) in comparison with the values determined using standard method. Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents and has potential as an early warning detection device.

Renal glucose handling in diabetes and sodium glucose cotransporter 2 inhibition

Directory of Open Access Journals (Sweden)

Resham Raj Poudel

2013-01-01

Full Text Available The kidneys play a major role in glucose homeostasis through its utilization, gluconeogenesis, and reabsorption via sodium glucose cotransporters (SGLTs. The defective renal glucose handling from upregulation of SGLTs, mainly the SGLT2, plays a fundamental role in the pathogenesis of type 2 diabetes mellitus. Genetic mutations in a SGLT2 isoform that results in benign renal glycosuria, as well as clinical studies with SGLT2 inhibitors in type 2 diabetes support the potential of this approach. These studies indicate that inducing glycosuria by suppressing SGLT2 can reduce plasma glucose and A1c levels, as well as decrease weight, resulting in improved β-cell function and enhanced insulin sensitivity in liver and muscle. Because the mechanism of SGLT2 inhibition is independent of insulin secretion and sensitivity, these agents can be combined with other antidiabetic agents, including exogenous insulin. This class represents a novel therapeutic approach with potential for the treatment of both type 2 and type 1 diabetes.

High-Order Ca(II)-Chloro Complexes in Mixed CaCl2-LiCl Aqueous Solution: Insights from Density Functional Theory and Molecular Dynamics Simulations.

Science.gov (United States)

Wang, Yu-Lin; Wang, Ying; Yi, Hai-Bo

2016-07-21

In this study, the structural characteristics of high-coordinated Ca-Cl complexes present in mixed CaCl2-LiCl aqueous solution were investigated using density functional theory (DFT) and molecular dynamics (MD) simulations. The DFT results show that [CaClx](2-x) (x = 4-6) clusters are quite unstable in the gas phase, but these clusters become metastable when hydration is considered. The MD simulations show that high-coordinated Ca-chloro complexes are possible transient species that exist for up to nanoseconds in concentrated (11.10 mol·kg(-1)) Cl(-) solution at 273 and 298 K. As the temperature increases to 423 K, these high-coordinated structures tend to disassociate and convert into smaller clusters and single free ions. The presence of high-order Ca-Cl species in concentrated LiCl solution can be attributed to their enhanced hydration shell and the inadequate hydration of ions. The probability of the [CaClx](2-x)aq (x = 4-6) species being present in concentrated LiCl solution decreases greatly with increasing temperature, which also indicates that the formation of the high-coordinated Ca-Cl structure is related to its hydration characteristics.

The dynamics of ammonium ions in K1-x(NH4)xCl mixed crystals by the neutron scattering study

International Nuclear Information System (INIS)

Smirnov, L.S.; Natkanets, I.; Shuvalov, L.A.; Dolbinina, V.V.

2004-01-01

The study of vibrational spectrum of the K 1-x (NH 4 ) x Cl mixed crystals in a dynamically disordered cubic α-phase at 10 K is carried out by means of inelastic incoherent neutron scattering on the NERA-PR time-of-flight spectrometer set at the IBR-2 reactor (JINR, Dubna). It is shown that low-energy modes of ammonium ions with the energies 19-23 and 62-63 cm -1 at 10 K are observed only within the disordered cubic α-phase and are absent in the ordered cubic δ-phase of NH 4 Cl. The energies of local translation and libration modes of ammonium ions are determined in the α- and δ-phases of the K 1-x (NH 4 ) x Cl mixed crystals

Thermodynamic properties of thulium and ytterbium in fused NaCl-KCl-CsCl eutectic

Energy Technology Data Exchange (ETDEWEB)

Novoselova, A., E-mail: A.Novoselova@ihte.uran.ru [Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, S. Kovalevskaya Str., 22, Ekaterinburg 620990 (Russian Federation); Smolenski, V. [Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, S. Kovalevskaya Str., 22, Ekaterinburg 620990 (Russian Federation)

2011-07-15

Research highlights: > Tm and Yb chloride compounds as fission products. > The investigation of electrochemical properties of lanthanides. > Determination of the apparent standard redox potentials of the couple Ln(III)/Ln(II) in fused NaCl-KCl-CsCl eutectic at (823 to 973) K. > The calculation of the basic thermodynamic properties of redox reaction in molten salt. - Abstract: This work presents the results of a study of the Tm{sup 3+}/Tm{sup 2+} and Yb{sup 3+}/Yb{sup 2+} couple redox potentials vs. Cl{sup -}/Cl{sub 2} reference electrode at the temperature range (823 to 973) K in fused NaCl-KCl-CsCl eutectic by direct potentiometric method. Initial concentrations of TmCl{sub 3} and YbCl{sub 3} in solvents did not exceed 5.0 mol%. Basic thermodynamic properties of the reactions TmCl{sub 2(l)} + 1/2 Cl{sub 2(g)} {r_reversible} TmCl{sub 3(l)} and YbCl{sub 2(l)} + 1/2 Cl{sub 2(g)} {r_reversible} YbCl{sub 3(l)} were calculated using the temperature dependencies of apparent standard potentials of the couples E{sub Tm{sup 3+}/Tm{sup 2+*}} and E{sub Yb{sup 3+}/Yb{sup 2+*}}.

Preparation of Ferrotitanium Alloys by Electrolysis-Assisted Calciothermic Reduction of Ilmenite in Equimolar CaCl2-NaCl Electrolyte: Effect of Calcium Oxide

Science.gov (United States)

Zhou, Zhongren; Zhang, Yingjie; Hua, Yixin; Xu, Cunying; Dong, Peng; Zhang, Qibo; Wang, Ding

2018-04-01

The effect of CaO content on the preparation of ferrotitanium alloys from ilmenite with the method of the electrolysis-assisted calciothermic reduction has been investigated by use of ilmenite powders as raw materials that positions them next to the cathodic molybdenum plate, equimolar CaCl2-NaCl molten salt with 2-7 mol.% CaO as electrolyte and graphite as anode at 700°C with cell voltage of 2.8 V under argon atmosphere. It is demonstrated that increasing the reactant CaO content is beneficial to the calciothermic reduction of ilmenite and the intermediate CaTiO3. Experimental results also show that after 14 h of calciothermic reduction process, the products are ferrotitanium alloys and the specific energy consumption is only about 10.21 kWh kg-1 when adding 5 mol.% CaO into equimolar CaCl2-NaCl molten salt and approximately 14.40 kWh kg-1 when CaO content is increased to 7 mol.%.

Thermodynamic investigation of the ternary mixed aqueous electrolyte (MgCl{sub 2} + MgSO{sub 4}) system by potentiometric method at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Bagherinia, Mohammad A., E-mail: mabagherinia@yahoo.com [Department of Chemistry, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan (Iran, Islamic Republic of); Giahi, Masoud; Pournaghdy, Mohammad; Vaghar, Gholam R. [Department of Chemistry, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan (Iran, Islamic Republic of)

2012-01-15

Highlights: > In this study we investigated the thermodynamic properties of MgCl{sub 2} + MgSO{sub 4} + H{sub 2}O. > The method used in this work was potentiometric method. > Mg-ISE and the Ag/AgCl electrodes used in this work had a good Nernst response. > The experimental results obeyed the Harned rule. > The Pitzer model could be used to describe this ternary system satisfactorily. - Abstract: This work reports the results of thermodynamic investigation of the ternary mixed-electrolyte system (MgCl{sub 2} + MgSO{sub 4} + H{sub 2}O). The investigation was performed based on Pitzer ion interaction model by using the potentiometric technique at T = 298.15 K. The mean activity coefficients of MgCl{sub 2} in the mixed aqueous electrolyte system were determined on the galvanic cell without liquid junction of the type: Mg-ISE|MgCl{sub 2} (m{sub A}), MgSO{sub 4} (m{sub B}), H{sub 2}O|Ag/AgCl over total ionic strengths from (0.001 to 8.000) mol . kg{sup -1} for different series of salt ratio r (r=m{sub MgCl{sub 2}}/m{sub MgSO{sub 4}}=2.5,5.0,7.5,10.0,15.0 and pure MgCl{sub 2}). The PVC based magnesium ion-selective electrode (Mg-ISE) and the Ag/AgCl electrode used in this work were made in our laboratory and had a reasonably good Nernst response. The experimental results obeyed the Harned rule, and the Pitzer model could be used to describe this ternary system satisfactorily. Pitzer ion-interaction parameters for mixed salts were determined for this system. Then, these parameters ({theta}{sub ClSO{sub 4}}=0.0252{+-}0.0042, {psi}{sub MgClSO{sub 4}}=-0.0049{+-}0.0003) were used to calculate the values of the mean activity coefficients of MgSO{sub 4}, the osmotic coefficients of water ({phi}) and the excess Gibbs free energies of solution (G{sup E}) for the whole series of the studied electrolyte systems.

Determination of the equilibrium constant of FeZrCl6 formation from FeCl3 and ZrCl4

International Nuclear Information System (INIS)

Berdonosov, S.S.; Kharisov, B.I.; Nikitin, M.I.

1992-01-01

Equilibrium pressures of chlorine formed in the course of reaction FeCl 3 +ZrCl 4 ↔ FeZrCl 6 +0.5 Cl 2 were determined at the temperatures of 250-325 deg C. The values of equilibrium constant K p of the reaction mentioned at the temperatures of 250, 275, 300 and 325 deg were calculated, taking into consideration the determined values of p Cl2 and literature data on equilibrium pressures of ZrCl 4 and FeCl 3 vapours

Use of 86Rb and 22Na in assaying active and cotransport activities in hum erythrocytes in a biracial population

International Nuclear Information System (INIS)

Sharma, C.; Dalferes, E.R. Jr; Freedman, D.S.; Asamoah, A.; Berenson, G.S.

1988-01-01

A defect in Na/sup +/-K/sup +/ transport across the red cell membrane has been shown to be associated with essential hypertension. A sensitive assay system to measure active, co- and countertransport systems in erythrocytes from normotensive adults was developed. Active, co- and countertransport systems in the erythrocytes were assayed by measuring the influx of radioactive /sup 22/Na/sup +/ and /sup 86/Rb/ sup +/. In the biracial (black-white) population group studied, analysis of variance of the active transport showed a significant race effect. Cotransport activity showed age by race interaction and age by sex. Cotransport activity was significantly higher in whites than blacks. The results suggest a subtle difference in Na/sup +/-K/sup +/ transport systems between blacks and whites, and these variations may be related to differences for susceptibility to essential hypertension

The effects of sodium-glucose co-transporter 2 inhibitors in patients with type 2 diabetes

DEFF Research Database (Denmark)

Storgaard, Heidi; Gluud, Lise Lotte; Christensen, Mikkel

2014-01-01

INTRODUCTION: Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) increase urinary glucose excretion through a reduced renal glucose reabsorption. We plan to perform a systematic review of SGLT-2i for treatment of type 2 diabetes. METHODS AND ANALYSIS: A systematic review with meta......-analyses of randomised clinical trials on SGLT-2i versus placebo, other oral glucose lowering drugs or insulin for patients with type 2 diabetes will be performed. The primary end point will be the glycated haemoglobin. Secondary end points will include changes in body weight, body mass index, fasting plasma glucose...... to the knowledge regarding the beneficial and harmful effects of SGLT-2i in patients with type 2 diabetes. We plan to publish the study irrespective of the results. RESULTS: The study will be disseminated by peer-review publication and conference presentation. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014008960...

75 FR 37994 - Airworthiness Directives; Bombardier, Inc. Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL...

Science.gov (United States)

2010-07-01

... provides data for replacement of the accumulators. The commenter requests that stronger language be... numbers 1004 through 1085 inclusive; (2) Bombardier, Inc. CL-600-2A12 (CL-601) airplanes, serial numbers 3001 through 3066 inclusive; and (3) Bombardier, Inc. CL-600-2B16 (CL-601-3A, CL-601-3R, and CL- 604...

NIR emitting K2SrCl4:Eu2+, Nd3+ phosphor as a spectral converter for CIGS solar cell

Science.gov (United States)

Tawalare, P. K.; Bhatkar, V. B.; Omanwar, S. K.; Moharil, S. V.

2018-05-01

Intense near-infrared emitting phosphor K2SrCl4:Eu2+,Nd3+ with various concentrations of Nd3+ were synthesized. These are characterized with X-ray diffraction, reflectance, photoluminescence emission and photoluminescence excitation spectroscopy, PL lifetime measurements. The emission can be excited by a broad band in near ultra violet region as a consequence of Eu2+→Nd3+ energy transfer. The efficiency of Eu2+→Nd3+ energy transfer is as high as 95%. Fluorescence decay curves for Eu2+ doped samples are almost exponential and described by τ = 500 ns. Eu2+ lifetimes are shortened after Nd3+ doping. Near infrared Emission intensity is limited by Nd3+→Nd3+ energy transfer and the consequent concentration quenching. Nd3+ emission matches well with the spectral response of CIGS and CIS solar cells. Absorption of near ultra violet radiations followed by conversion to near infrared indicates the potential application in solar photovoltaics.

Magnetic properties of 1 : 4 complexes of CoCl2 and pyridines carrying carbenes (S(0) = 4/2, 6/2, and 8/2) in diluted frozen solution; influence of carbene multiplicity on heterospin single-molecule magnets.

Science.gov (United States)

Karasawa, Satoru; Nakano, Kimihiro; Tanokashira, Jun-ichi; Yamamoto, Noriko; Yoshizaki, Takahito; Koga, Noboru

2012-11-28

The microcrystalline sample of a parent complex, [CoCl(2)(py)(4)], showed a single-molecule magnet (SMM) behavior with an effective activation barrier, U(eff)/k(B), of 16 K for reversal of the magnetism in the presence of a dc field of 3 kOe. Pyridine ligands having 2-4 diazo moieties, DYpy; Y = 2, 3l, 3b, and 4, were prepared and confirmed to be quintet, septet, septet, and nonet in the ground state, respectively, after irradiation. The 1 : 4 complexes, CoCl(2)(DYpy)(4); Y = 2, 3l, 3b, and 4 in frozen solutions after irradiation showed the magnetic behaviors of SMMs with total spin multiplicity, S(total) = 17/2, 25/2, 25/2, and 33/2, respectively. Hysteresis loops depending on the temperature were observed and the values of coercive force, H(c), at 1.9 K were 12, 8.4, 11, and 8.1 kOe for CoCl(2)(CYpy)(4); Y = 2, 3l, 3b, and 4, respectively. In dynamic magnetic susceptibility experiments, ac magnetic susceptibility data obeyed the Arrhenius law to give U(eff)/k(B) values of 94, 92, 93, and 87 K for CoCl(2)(CYpy)(4); Y = 2, 3l, 3b, and 4, respectively, while the relaxation times for CoCl(2)(CYpy)(4); Y = 2 and 3l, obtained by dc magnetization decay in the range of 3.5-1.9 K slightly deviated downward from Arrhenius plots on cooling. The dynamic magnetic behaviors for CoCl(2)(CYpy)(4) including [CoCl(2)(py)(4)] and CoCl(2)(C1py)(4) suggested that the generated carbenes interacted with the cobalt ion to increase the relaxation time, τ(q), due to the spin quantum tunneling magnetization, which became larger with increasing S(total) of the complex.

Absorption spectra and Faraday effect in Cs2NaNdCl6 and Cs2NaPrCl6 crystals

International Nuclear Information System (INIS)

Ehdel'man, I.S.; Galanov, E.K.; Kokov, I.T.; Malakhovskij, A.V.; Anistratov, A.T.

1985-01-01

The paper is devoted to studying absorption spectra and the Faraday effect in Cs 2 NaNdCl 6 and Cs 2 NaPrCl 6 crystals. The absorption spectra and Faraday effect were measured at room temperature in the range of 9000-30000 cmsup(-1) (0.33-1.2 μm) in 0-10 kOe magnetic fields. The absorption spectra produced contain several groups of intense absorption bands resulted from intraconfiguration electron transitions in rare-earth cations. The Faraday spectra in the whole range studied for both crystals have the form of smoothly dipping curves when increasing wavelength. The form of these curves testifies to prevailing contribution of strong electron transitions lying in a nearer UV region to the Faraday effect

Difference in {sup 201}TlCl accumulation mechanism in brain tumors. A comparison of their Na{sup +}-K{sup +} ATPase activities

Energy Technology Data Exchange (ETDEWEB)

Sugo, Nobuo; Kuroki, Takao; Nemoto, Masaaki; Mito, Toshiaki; Seiki, Yoshikatsu; Shibata, Iekado [Toho Univ., Tokyo (Japan). Omori Hospital

2000-07-01

The accumulation levels of {sup 201}TlCl and Na{sup +} -K{sup +} ATPase activity in tumor tissue were compared among glioblastoma, benign glioma and meningioma to study the difference in the mechanism of {sup 201}TlCl accumulation. The subjects were 19 cases comprised of 6 glioblastoma, 2 oligodendroglioma, 1 fibrillary astrocytoma, 1 pilocytic astrocytoma and 9 meningioma. Preoperative {sup 201}TlCl SPECT was performed in all the cases, and Thallium Index (TL index) was calculated by a ratio of {sup 201}TlCl in the tumor area and the contralateral area. In addition, cell membrane was extracted from the tumor tissue collected intraoperatively to determine Na{sup +} -K{sup +} ATPase activity. No statistically significant difference in TL index was noted between the glioblastoma group (6.97{+-}2.67) and the meningioma group (5.87{+-}1.99). This fact showed that there was no difference in the accumulation level of {sup 201}TlCl between the two groups. On the other hand, the glioblastoma group indicated a higher value of Na{sup +} -K{sup +} ATPase activity (49.13{+-}43.76 {mu}mole/hour/mg protein) than the meningioma group (7.73{+-}13.84 {mu}mol/hour/mg protein) (p<0.05, t test). These results suggested the involvement of Na{sup +} -K{sup +} ATPase activity in {sup 201}TlCl accumulation in glioblastoma and the influences of other accumulation mechanism than Na{sup +} -K{sup +} ATPase activity such as the volume of intratumoral vascular bed in meningioma. (author)

Effect of low irradiation temperature on the thermoluminescent response of doped crystal NaCl:XCl2 :MnCl2(X=Ca, Cd)

International Nuclear Information System (INIS)

Ortiz M, A.; Cruz Z, E.; Furetta, C.; Kitis, G.

2009-10-01

Production of crystalline materials suitable thermoluminescent properties over a wide range of doses is becoming more important to evaluate different radiation fields. However, the thermoluminescence response and the structure of the glow curves may be modified by the participation of defects to low irradiation temperature. In this work it is analyzed the effect of the irradiation temperature, 77 and 200 K on the thermoluminescence response of crystal NaCl:XCl 2 :MnCl 2 (X=Ca, Cd) doubly doped. The glow curves obtained were analyzed using a deconvolution program of CGCD, and the response linearity was analyzed by supra linearity index. (Author)

Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O

Directory of Open Access Journals (Sweden)

Erik Hennings

2014-12-01

Full Text Available The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O5] (pentaaqua-μ-chlorido-trichloridodizinc. The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.

Crystal-field analysis of U3+ ions in K2LaX5 (X=Cl, Br or I) single crystals

Science.gov (United States)

Karbowiak, M.; Edelstein, N.; Gajek, Z.; Drożdżyński, J.

1998-11-01

An analysis of low temperature absorption spectra of U3+ ions doped in K2LaX5 (X=Cl, Br or I) single crystals is reported. The energy levels of the U3+ ion in the single crystals were assigned and fitted to a semiempirical Hamiltonian representing the combined atomic and crystal-field interactions at the Cs symmetry site. An analysis of the nephelauxetic effect and crystal-field splittings in the series of compounds is also reported.

Water permeation through the sodium-dependent galactose cotransporter vSGLT.

Science.gov (United States)

Choe, Seungho; Rosenberg, John M; Abramson, Jeff; Wright, Ernest M; Grabe, Michael

2010-10-06

It is well accepted that cotransporters facilitate water movement by two independent mechanisms: osmotic flow through a water channel in the protein and flow driven by ion/substrate cotransport. However, the molecular mechanism of transport-linked water flow is controversial. Some researchers believe that it occurs via cotransport, in which water is pumped along with the transported cargo, while others believe that flow is osmotic in response to an increase in intracellular osmolarity. In this letter, we report the results of a 200-ns molecular dynamics simulation of the sodium-dependent galactose cotransporter vSGLT. Our simulation shows that a significant number of water molecules cross the protein through the sugar-binding site in the presence as well as the absence of galactose, and 70-80 water molecules accompany galactose as it moves from the binding site into the intracellular space. During this event, the majority of water molecules in the pathway are unable to diffuse around the galactose, resulting in water in the inner half of the transporter being pushed into the intracellular space and replaced by extracellular water. Thus, our simulation supports the notion that cotransporters act as both passive water channels and active water pumps with the transported substrate acting as a piston to rectify the motion of water. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Atmospheric chemistry of CF3CF═CH2 and (Z)-CF3CF═CHF: Cl and NO3 rate coefficients, Cl reaction product yields, and thermochemical calculations.

Science.gov (United States)

Papadimitriou, Vassileios C; Lazarou, Yannis G; Talukdar, Ranajit K; Burkholder, James B

2011-01-20

Rate coefficients, k, for the gas-phase reactions of Cl atoms and NO(3) radicals with 2,3,3,3-tetrafluoropropene, CF(3)CF═CH(2) (HFO-1234yf), and 1,2,3,3,3-pentafluoropropene, (Z)-CF(3)CF═CHF (HFO-1225ye), are reported. Cl-atom rate coefficients were measured in the fall-off region as a function of temperature (220-380 K) and pressure (50-630 Torr; N(2), O(2), and synthetic air) using a relative rate method. The measured rate coefficients are well represented by the fall-off parameters k(0)(T) = 6.5 × 10(-28) (T/300)(-6.9) cm(6) molecule(-2) s(-1) and k(∞)(T) = 7.7 × 10(-11) (T/300)(-0.65) cm(3) molecule(-1) s(-1) for CF(3)CF═CH(2) and k(0)(T) = 3 × 10(-27) (T/300)(-6.5) cm(6) molecule(-2) s(-1) and k(∞)(T) = 4.15 × 10(-11) (T/300)(-0.5) cm(3) molecule(-1) s(-1) for (Z)-CF(3)C═CHF with F(c) = 0.6. Reaction product yields were measured in the presence of O(2) to be (98 ± 7)% for CF(3)C(O)F and (61 ± 4)% for HC(O)Cl in the CF(3)CF═CH(2) reaction and (108 ± 8)% for CF(3)C(O)F and (112 ± 8)% for HC(O)F in the (Z)-CF(3)CF═CHF reaction, where the quoted uncertainties are 2σ (95% confidence level) and include estimated systematic errors. NO(3) reaction rate coefficients were determined using absolute and relative rate methods. Absolute measurements yielded upper limits for both reactions between 233 and 353 K, while the relative rate measurements yielded k(3)(295 K) = (2.6 ± 0.25) × 10(-17) cm(3) molecule(-1) s(-1) and k(4)(295 K) = (4.2 ± 0.5) × 10(-18) cm(3) molecule(-1) s(-1) for CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF, respectively. The Cl-atom reaction with CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF leads to decreases in their atmospheric lifetimes and global warming potentials and formation of a chlorine-containing product, HC(O)Cl, for CF(3)CF═CH(2). The NO(3) reaction has been shown to have a negligible impact on the atmospheric lifetimes of CF(3)CF═CH(2) and (Z)-CF(3)CF═CHF. The energetics for the reaction of Cl, NO(3), and OH with CF

On chlorization of uranium and plutonium oxides in NaCl-KCl-MgCl2 molten eutectic

International Nuclear Information System (INIS)

Vorobej, M.P.; Desyatnik, V.N.; Pirogov, S.M.

1978-01-01

The chlorination process of U 3 O 8 , UO 2 , and PuO 2 in a melt of anhydrous NaCl-KCl-MgCl 2 with gaseous chlorine and carbon tetrachloride has been studied. The chlorination rate of uranium oxides has been studied within a temperature range 500-800 deg C at a chlorine feeding rate of 10 ml/min. Thermoqravimetric and X-ray analyses have shown that K 2 UO 2 Cl 4 compound is the final product of chlorination of uranium oxides. The mechanism of chlorination has been proposed. THe rate of PuO 2 chlorination has been studied within the same temperature range. It has been established that PuO 2 is readily chlorinated with CCl 4 vapours at a feeding rate of 10 ml/min. In contrast to uranium, chloride forms of plutonium in a highest oxidized state are unstable and are reduced in the melt to Pu(3) and Pu(4). The oxygen being released is retained by CCl 4 and by the products of CCl 4 pyrolysis

Thermodynamic Modeling of Poorly Complexing Metals in Concentrated Electrolyte Solutions: An X-Ray Absorption and UV-Vis Spectroscopic Study of Ni(II) in the NiCl2-MgCl2-H2O System

Science.gov (United States)

Zhang, Ning; Brugger, Joël; Etschmann, Barbara; Ngothai, Yung; Zeng, Dewen

2015-01-01

Knowledge of the structure and speciation of aqueous Ni(II)-chloride complexes is important for understanding Ni behavior in hydrometallurgical extraction. The effect of concentration on the first-shell structure of Ni(II) in aqueous NiCl2 and NiCl2-MgCl2 solutions was investigated by Ni K edge X-ray absorption (XAS) and UV-Vis spectroscopy at ambient conditions. Both techniques show that no large structural change (e.g., transition from octahedral to tetrahedral-like configuration) occurs. Both methods confirm that the Ni(II) aqua ion (with six coordinated water molecules at R Ni-O = 2.07(2) Å) is the dominant species over the whole NiCl2 concentration range. However, XANES, EXAFS and UV-Vis data show subtle changes at high salinity (> 2 mol∙kg-1 NiCl2), which are consistent with the formation of small amounts of the NiCl+ complex (up to 0.44(23) Cl at a Ni-Cl distance of 2.35(2) Å in 5.05 mol∙kg-1 NiCl2) in the pure NiCl2 solutions. At high Cl:Ni ratio in the NiCl2-MgCl2-H2O solutions, small amounts of [NiCl2]0 are also present. We developed a speciation-based mixed-solvent electrolyte (MSE) model to describe activity-composition relationships in NiCl2-MgCl2-H2O solutions, and at the same time predict Ni(II) speciation that is consistent with our XAS and UV-Vis data and with existing literature data up to the solubility limit, resolving a long-standing uncertainty about the role of chloride complexing in this system. PMID:25885410

The topotactic reduction of Sr3Fe2O5Cl2-square planar Fe(II) in an extended oxyhalide.

Science.gov (United States)

Dixon, Edward; Hayward, Michael A

2010-10-18

The topotactic reduction of the oxychloride Sr(3)Fe(2)O(5)Cl(2) with LiH results in the formation of Sr(3)Fe(2)O(4)Cl(2). Neutron powder diffraction data show that Sr(3)Fe(2)O(4)Cl(2) adopts a body-centered tetragonal crystal structure (I4/mmm, a = 4.008(1) Å, c = 22.653(1) Å at 388 K) with anion vacancies located within the SrO layer of the phase. This leads to a structure consisting of infinite sheets of corner-sharing Fe(II)O(4) square planes. Variable-temperature neutron diffraction data show that Sr(3)Fe(2)O(4)Cl(2) adopts G-type antiferromagnetic order below T(N) ∼ 378(10) K with an ordered moment of 2.81(9) μ(B) per iron center at 5 K consistent with the presence of high-spin Fe(II). The observed structural and chemical selectivity of the reduction reaction is discussed. The contrast between the structure of Sr(3)Fe(2)O(4)Cl(2) and the isoelectronic all-oxide analogue (Sr(3)Fe(2)O(5)) suggests that by careful selection of substrate phases, the topotactic reduction of complex transition metal oxychlorides can lead to the preparation of novel anion-deficient phases with unique transition metal-oxygen sublattices which cannot be prepared via the reduction of all-oxide substrates.

Characterization of the Fermi surface of BEDT-TTF4[Hg2Cl6].PhCl by electronic band structure calculations

International Nuclear Information System (INIS)

Veiros, L.F.; Canadell, E.

1994-01-01

Tight-binding band structure calculations for the room temperature structure of BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl show the existence of closed electron and hole Fermi surfaces, in agreement with the 2D metallic conductivity of this salt. It is shown that these closed Fermi surfaces result from the hybridization of two hidden 1D Fermi surfaces. However, our study also shows that a transition associated with either a usual or a hidden nesting type mechanism is unlikely. This explains why this salt retains its metallic properties without any resistivity anomaly down to 1.3 K. Our study suggests that BEDT-TTF 4 [Hg 2 Cl 6 ]-PhCl is somewhat anisotropic 2D semimetal and should exhibit Shubnikov-de Haas oscillations corresponding to a cross-sectional area of approximately 13% of the first Brillouin zone. (orig.)

Isopiestic Investigation of the Osmotic and Activity Coefficients of {yMgCl2 + (1 - y)MgSO4}(aq) and the Osmotic Coefficients of Na2SO4.MgSO4(aq) at 298.15 K