Science.gov

Sample records for palpebras na posicao

  1. Aponeurosis of the levator palpebrae superioris in Chinese subjects

    PubMed Central

    Pan, Er; Nie, Yun-Fei; Wang, Zhen-Jun; Peng, Li-Xia; Wu, Yan-Hong; Li, Qin

    2016-01-01

    Abstract An accurate understanding of the anatomy of the levator palpebrae superioris aponeurosis (LPSA) is critical for successful blepharoplasty of aponeurotic ptosis. We investigated the macroscopic and microscopic anatomy of the LPSA. This prospective live gross anatomy study enrolled 200 adult Chinese patients with bilateral mild ptosis undergoing elective blepharoplasty. Full-thick eyelid tissues and sagittal sections from the eyelid skin to the conjunctiva were examined with Masson trichrome staining or antismooth muscle actin (SMA) immunohistochemistry. Gross anatomy showed that the space between the superficial and deep layers of the LPSA could be accessed after incising the overlying superficial fascia, by retracting the white line. Adipose layers were clearly observed in 195 out of 200 patients with bilateral mild ptosis, among which 180 cases had the superficial layer connected to the uncoated adipose. Fifteen cases had the superficial layer connected to the smoothly coated layer, and 5 cases had the superficial layer directly connected to the deep loose fiber, almost without adipose. In previously untreated patients, the LPSA space was located beneath the intact orbital septum. In those with previous surgeries, it was beneath the superficial layer of the LPSA, underlying the destructed orbital septum. Cadaveric histology showed that the deep layer of the LPSA extended into the anterior layer of the tarsal plate and the superficial layer reflexed upward in continuity with the vertical orbital septum. An occult space existed between the 2 layers of the LPSA, with a smooth lining on the deep layer. The superficial layer of the LPSA was SMA-immunonegative but the deep layer was slightly immunopositive for SMA. An occult anatomic space exists between the superficial and deep layers of the LPSA, in proximity to the superior tarsal plate margin. Recognition of the more anatomically significant LPSA deep layer may help improve the aesthetic outcome of

  2. Evidence of ancillary trigeminal innervation of levator palpebrae in the general population.

    PubMed

    Lehman, A M; Dong, C C; Harries, A M; Patel, A; Honey, C R; Patel, M S

    2014-02-01

    The cranial synkineses are a group of disorders encompassing a variety of involuntary co-contractions of the facial, masticatory, or extraocular muscles that occur during a particular volitional movement. The neuroanatomical pathways for synkineses largely remain undefined. Our studies explored a normal synkinesis long observed in the general population - that of jaw opening during efforts to open the eyelids widely. To document this phenomenon, we observed 186 consecutive participants inserting or removing contact lenses to identify jaw opening. Seeking electrophysiological evidence, in a second study we enrolled individuals undergoing vascular decompression for trigeminal neuralgia or hemifacial spasm, without a history of jaw-winking, ptosis, or strabismus, to record any motor responses in levator palpebrae superioris (LPS) upon stimulation of the trigeminal motor root. Stimulus was applied to the trigeminal motor root while an electrode in levator recorded the response. We found that 37 participants (20%) opened their mouth partially or fully during contact lens manipulation. In the second study, contraction of LPS with trigeminal motor stimulation was documented in two of six patients, both undergoing surgery for trigeminal neuralgia. We speculate these results might provide evidence of an endogenous synkinesis, indicating that trigeminal-derived innervation of levator could exist in a significant minority of the general population. Our observations demonstrate plasticity in the human cranial nerve innervation pattern and may have implications for treating Marcus Gunn jaw-winking. PMID:24120706

  3. Size and Location of the Superior Transverse Ligament and Muscle-Aponeurosis Junction of the Levator Palpebrae Superioris.

    PubMed

    Kim, Yeon Soo; Hwang, Kun

    2016-06-01

    The aim of this study is to elucidate the size and location of the superior transverse ligament and the muscle-aponeurosis junction (MAJ) of the levator palpebrae superioris.Forty-six eyelids from Korean adult cadavers (32 males, 14 females) were used. Through a cranial approach, orbital plates and orbital fat were removed. Then, the levator palpebrae superioris and superior transverse ligaments (STL) were exposed. The widths and locations of the STL were measured in relation to the supraorbital rim. The width and location of the MAJ was measured in reference to the medial and lateral canthi, orbital rims, and tarsal plate.The widths of the bony orbit and palpebral fissure were 42.4 ± 3.5 and 33.3 ± 4.4 mm, respectively. The width of the STL was 9.0 ± 2.5 mm. In 3 of 4 of the specimens, the anterior border of the STL was located posterior to the supraorbital rim (3.5 ± 1.3 mm). In about one-quarter of the specimens, it was located anterior at the supraorbital rim (2.3 ± 1.1 mm). The average width of MAJ was 20.9 ± 2.6 mm. The distance from the medial orbital rim to the medial end of the MAJ was 15.2 ± 3.2 mm. The distance from the lateral orbital rim to the lateral end of the MAJ was 6.9 ± 3.9 mm. The medial end of the MAJ was located 7.3 ± 3.0 mm medial to the medial canthus. In most of the cases, the lateral end of the MAJ was located medial to the lateral canthus (6.3 ± 4, 5 mm medial). The MAJ was located 8.7 ± 1.8 mm superior to the highest point of the tarsal plate.This anatomical knowledge could be help in blepharoptosis surgeries. PMID:27171966

  4. Aponeurosis of the levator palpebrae superioris in Chinese subjects: A live gross anatomy and cadaveric histological study.

    PubMed

    Pan, Er; Nie, Yun-Fei; Wang, Zhen-Jun; Peng, Li-Xia; Wu, Yan-Hong; Li, Qin

    2016-08-01

    An accurate understanding of the anatomy of the levator palpebrae superioris aponeurosis (LPSA) is critical for successful blepharoplasty of aponeurotic ptosis. We investigated the macroscopic and microscopic anatomy of the LPSA.This prospective live gross anatomy study enrolled 200 adult Chinese patients with bilateral mild ptosis undergoing elective blepharoplasty. Full-thick eyelid tissues and sagittal sections from the eyelid skin to the conjunctiva were examined with Masson trichrome staining or antismooth muscle actin (SMA) immunohistochemistry.Gross anatomy showed that the space between the superficial and deep layers of the LPSA could be accessed after incising the overlying superficial fascia, by retracting the white line. Adipose layers were clearly observed in 195 out of 200 patients with bilateral mild ptosis, among which 180 cases had the superficial layer connected to the uncoated adipose. Fifteen cases had the superficial layer connected to the smoothly coated layer, and 5 cases had the superficial layer directly connected to the deep loose fiber, almost without adipose. In previously untreated patients, the LPSA space was located beneath the intact orbital septum. In those with previous surgeries, it was beneath the superficial layer of the LPSA, underlying the destructed orbital septum. Cadaveric histology showed that the deep layer of the LPSA extended into the anterior layer of the tarsal plate and the superficial layer reflexed upward in continuity with the vertical orbital septum. An occult space existed between the 2 layers of the LPSA, with a smooth lining on the deep layer. The superficial layer of the LPSA was SMA-immunonegative but the deep layer was slightly immunopositive for SMA. An occult anatomic space exists between the superficial and deep layers of the LPSA, in proximity to the superior tarsal plate margin. Recognition of the more anatomically significant LPSA deep layer may help improve the aesthetic outcome of blepharoplasty

  5. Intracellular Na+ regulates epithelial Na+ channel maturation.

    PubMed

    Heidrich, Elisa; Carattino, Marcelo D; Hughey, Rebecca P; Pilewski, Joseph M; Kleyman, Thomas R; Myerburg, Mike M

    2015-05-01

    Epithelial Na(+) channel (ENaC) function is regulated by the intracellular Na(+) concentration ([Na(+)]i) through a process known as Na(+) feedback inhibition. Although this process is known to decrease the expression of proteolytically processed active channels on the cell surface, it is unknown how [Na(+)]i alters ENaC cleavage. We show here that [Na(+)]i regulates the posttranslational processing of ENaC subunits during channel biogenesis. At times when [Na(+)]i is low, ENaC subunits develop mature N-glycans and are processed by proteases. Conversely, glycan maturation and sensitivity to proteolysis are reduced when [Na(+)]i is relatively high. Surface channels with immature N-glycans were not processed by endogenous channel activating proteases, nor were they sensitive to cleavage by exogenous trypsin. Biotin chase experiments revealed that the immature surface channels were not converted into mature cleaved channels following a reduction in [Na(+)]i. The hypothesis that [Na(+)]i regulates ENaC maturation within the biosynthetic pathways is further supported by the finding that Brefeldin A prevented the accumulation of processed surface channels following a reduction in [Na(+)]i. Therefore, increased [Na(+)]i interferes with ENaC N-glycan maturation and prevents the channel from entering a state that allows proteolytic processing. PMID:25767115

  6. Na+ coordination at the Na2 site of the Na+/I- symporter.

    PubMed

    Ferrandino, Giuseppe; Nicola, Juan Pablo; Sánchez, Yuly E; Echeverria, Ignacia; Liu, Yunlong; Amzel, L Mario; Carrasco, Nancy

    2016-09-13

    The sodium/iodide symporter (NIS) mediates active I(-) transport in the thyroid-the first step in thyroid hormone biosynthesis-with a 2 Na(+): 1 I(-) stoichiometry. The two Na(+) binding sites (Na1 and Na2) and the I(-) binding site interact allosterically: when Na(+) binds to a Na(+) site, the affinity of NIS for the other Na(+) and for I(-) increases significantly. In all Na(+)-dependent transporters with the same fold as NIS, the side chains of two residues, S353 and T354 (NIS numbering), were identified as the Na(+) ligands at Na2. To understand the cooperativity between the substrates, we investigated the coordination at the Na2 site. We determined that four other residues-S66, D191, Q194, and Q263-are also involved in Na(+) coordination at this site. Experiments in whole cells demonstrated that these four residues participate in transport by NIS: mutations at these positions result in proteins that, although expressed at the plasma membrane, transport little or no I(-) These residues are conserved throughout the entire SLC5 family, to which NIS belongs, suggesting that they serve a similar function in the other transporters. Our findings also suggest that the increase in affinity that each site displays when an ion binds to another site may result from changes in the dynamics of the transporter. These mechanistic insights deepen our understanding not only of NIS but also of other transporters, including many that, like NIS, are of great medical relevance.

  7. Na Cauda do Cometa

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  8. Regulation of the epithelial Na(+) channel by intracellular Na(+).

    PubMed

    Awayda, M S

    1999-08-01

    The hypothesis that the intracellular Na(+) concentration ([Na(+)](i)) is a regulator of the epithelial Na(+) channel (ENaC) was tested with the Xenopus oocyte expression system by utilizing a dual-electrode voltage clamp. [Na(+)](i) averaged 48.1 +/- 2.2 meq (n = 27) and was estimated from the amiloride-sensitive reversal potential. [Na(+)](i) was increased by direct injection of 27.6 nl of 0.25 or 0.5 M Na(2)SO(4). Within minutes of injection, [Na(+)](i) stabilized and remained elevated at 97.8 +/- 6.5 meq (n = 9) and 64. 9 +/- 4.4 (n = 5) meq 30 min after the initial injection of 0.5 and 0.25 M Na(2)SO(4), respectively. This increase of [Na(+)](i) caused a biphasic inhibition of ENaC currents. In oocytes injected with 0.5 M Na(2)SO(4) (n = 9), a rapid decrease of inward amiloride-sensitive slope conductance (g(Na)) to 0.681 +/- 0.030 of control within the first 3 min and a secondary, slower decrease to 0.304 +/- 0.043 of control at 30 min were observed. Similar but smaller inhibitions were also observed with the injection of 0.25 M Na(2)SO(4). Injection of isotonic K(2)SO(4) (70 mM) or isotonic K(2)SO(4) made hypertonic with sucrose (70 mM K(2)SO(4)-1.2 M sucrose) was without effect. Injection of a 0.5 M concentration of either K(2)SO(4), N-methyl-D-glucamine (NMDG) sulfate, or 0.75 M NMDG gluconate resulted in a much smaller initial inhibition (<14%) and little or no secondary decrease. Thus increases of [Na(+)](i) have multiple specific inhibitory effects on ENaC that can be temporally separated into a rapid phase that was complete within 2-3 min and a delayed slow phase that was observed between 5 and 30 min. PMID:10444397

  9. Solidification of NaCl-NaF eutectic in space

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yu, J. G.

    1974-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, have been produced in space and on earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis.

  10. Optical properties of NaCl-NaF eutectics

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yu, J. G.

    1976-01-01

    A new concept is advanced to explain the phenomenon of transmittance versus far-field infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelength is known. Experimental data are in excellent agreement with the theoretical prediction.

  11. Na+ recirculation and isosmotic transport.

    PubMed

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment. PMID:17206513

  12. Na+ recirculation and isosmotic transport.

    PubMed

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment.

  13. Drugs preventing Na+ and Ca2+ overload.

    PubMed

    Ravens, U; Himmel, H M

    1999-03-01

    Cardiac intracellular Na+and Ca2+homeostasis is regulated by the concerted action of ion channels, pumps and exchangers. The Na+, K+-ATPase produces the electrochemical concentration gradient for Na+, which is the driving force for Ca2+removal from the cytosol via the Na+/Ca2+exchange. Reduction of this gradient by increased intracellular Na+concentration leads to cellular Ca2+overload resulting in arrhythmias and contractile dysfunction. Na+and Ca2+overload-associated arrhythmias can be produced experimentally by inhibition of Na+efflux (digitalis-induced intoxication) and by abnormal Na+influx via modulated Na+channels (veratridine, DPI 201-106; hypoxia) or via the Na+, H+exchanger. Theoretically, blockers of Na+and Ca2+channels, inhibitors of abnormal oscillatory release of Ca2+from internal stores or modulators of the Na+, Ca2+and Na+, H+exchanger activities could protect against cellular Na+and Ca2+overload. Three exemplary drugs that prevent Na+and Ca2+overload, i.e. the benzothiazolamine R56865, the methylenephenoxydioxy-derivative CP-060S, and the benzoyl-guanidine Hoe 642, a Na+, H+exchange blocker, are briefly reviewed with respect to their efficacy on digitalis-, veratridine- and ischaemia/reperfusion-induced arrhythmias. PMID:10094840

  14. Na Deposition on MnO(100)

    NASA Astrophysics Data System (ADS)

    Feng, Xu; Cox, David F.

    2016-03-01

    Na deposition on the MnO(100) surface was investigated by temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED). Na TPD and XPS results indicate that adsorbed Na interacts strongly with the MnO substrate to form an irreversibly-adsorbed, oxidic Na compound on the surface for coverages up to 1 monolayer (ML). This strongly-bound Na diffuses into the MnO subsurface and bulk at elevated temperatures above 500 K. For Na coverages above 1 ML, metallic Na is present and desorbs from the surface below 500 K. The deposition of Na on MnO(100) follows a Stranski-Krastanov (SK) growth mode, with the formation of metallic Na islands following completion of the first Na monolayer. After Na deposition, the surface exhibits a diffuse (1 × 1) LEED pattern, suggesting the formation of disordered Na overlayers. After heating to 1000 K, the surface presents a (2 × 2) LEED pattern indicating that a surface reconstruction is induced by the diffusion of Na into the near surface region. CO2 can be used as a probe molecule in TPD to distinguish between metallic Na islands and oxidic Na in the first ML, and to indicate when Na that is still observable by XPS goes subsurface.

  15. β decay of Na32

    NASA Astrophysics Data System (ADS)

    Mattoon, C. M.; Sarazin, F.; Hackman, G.; Cunningham, E. S.; Austin, R. A. E.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Koopmans, K. A.; Leslie, J. R.; Phillips, A. A.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Svensson, C. E.; Waddington, J. C.; Walker, P. M.; Washbrook, B.; Zganjar, E.

    2007-01-01

    The β-decay of Na32 has been studied using β-γ coincidences. New transitions and levels are tentatively placed in the level scheme of Mg32 from an analysis of γ-γ and β-γ-γ coincidences. The observation of the indirect feeding of the 2321 keV state in Mg32 removes some restrictions previously placed on the spin assignment for this state. No evidence of a state at 2117 keV in Mg32 is found. Previously unobserved weak transitions up to 5.4 MeV were recorded but could not be placed in the decay scheme of Na32.

  16. Interactions of external and internal H+ and Na+ with Na+/Na+ and Na+/H+ exchange of rabbit red cells: evidence for a common pathway.

    PubMed

    Morgan, K; Canessa, M

    1990-12-01

    We have studied the kinetic properties of rabbit red cell (RRBC) Na+/Na+ and Na+/H+ exchanges (EXC) in order to define whether or not both transport functions are conducted by the same molecule. The strategy has been to determine the interactions of Na+ and H+ at the internal (i) and external (o) sites for both exchanges modes. RRBC containing varying Nai and Hi were prepared by nystatin and DIDS treatment of acid-loaded cells. Na+/Na+ EXC was measured as Nao-stimulated Na+ efflux and Na+/H+ EXC as Nao-stimulated H+ efflux and delta pHo-stimulated Na+ influx into acid-loaded cells. The activation of Na+/Na+ EXC by Nao at pHi 7.4 did not follow simple hyperbolic kinetics. Testing of different kinetic models to obtain the best fit for the experimental data indicated the presence of high (Km 2.2 mM) and low affinity (Km 108 mM) sites for a single- or two-carrier system. The activation of Na+/H+ EXC by Nao (pHi 6.6, Nai less than 1 mM) also showed high (Km 11 mM) and low (Km 248 mM) affinity sites. External H+ competitively inhibited Na+/Na+ EXC at the low affinity Nao site (KH 52 nM) while internally H+ were competitive inhibitors (pK 6.7) at low Nai and allosteric activators (pK 7.0) at high Nai. Na+/H+ EXC was also inhibited by acid pHo and allosterically activated by Hi (pK 6.4). We also established the presence of a Nai regulatory site which activates Na+/H+ and Na+/Na+ EXC modifying the affinity for Nao of both pathways. At low Nai, Na+/Na+ EXC was inhibited by acid pHi and Na+/H+ stimulated but at high Nai, Na+/Na+ EXC was stimulated and Na+/H+ inhibited being the sum of both pathways kept constant. Both exchange modes were activated by two classes of Nao sites, cis-inhibited by external Ho, allosterically modified by the binding of H+ to a Hi regulatory site and regulated by Nai. These findings are consistent with Na+/Na+ EXC being a mode of operation of the Na+/H+ exchanger. Na+/H+ EXC was partially inhibited (80-100%) by dimethyl-amiloride (DMA) but basal or

  17. The NA62 trigger system

    NASA Astrophysics Data System (ADS)

    Krivda, M.; NA62 Collaboration

    2013-08-01

    The main aim of the NA62 experiment (NA62 Technical Design Report, na62.web.cern.ch/NA62/Documents/TD_Full_doc_v1.pdf> [1]) is to study ultra-rare Kaon decays. In order to select rare events over the overwhelming background, central systems with high-performance, high bandwidth, flexibility and configurability are necessary, that minimize dead time while maximizing data collection reliability. The NA62 experiment consists of 12 sub-detector systems and several trigger and control systems, for a total channel count of less than 100,000. The GigaTracKer (GTK) has the largest number of channels (54,000), and the Liquid Krypton (LKr) calorimeter shares with it the largest raw data rate (19 GB/s). The NA62 trigger system works with 3 trigger levels. The first trigger level is based on a hardware central trigger unit, so-called L0 Trigger Processor (L0TP), and Local Trigger Units (LTU), which are all located in the experimental cavern. Other two trigger levels are based on software, and done with a computer farm located on surface. The L0TP receives information from triggering sub-detectors asynchronously via Ethernet; it processes the information, and then transmits a final trigger decision synchronously to each sub-detector through the Trigger and Timing Control (TTC) system. The interface between L0TP and the TTC system, which is used for trigger and clock distribution, is provided by the Local Trigger Unit board (LTU). The LTU can work in two modes: global and stand-alone. In the global mode, the LTU provides an interface between L0TP and TTC system. In the stand-alone mode, the LTU can fully emulate L0TP and so provides an independent way for each sub-detector for testing or calibration purposes. In addition to the emulation functionality, a further functionality is implemented that allows to synchronize the clock of the LTU with the L0TP and the TTC system. For testing and debugging purposes, a Snap Shot Memory (SSM) interface is implemented, that can work

  18. Europlanet NA2 Science Networking

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti; Szego, Karoly; Genzer, Maria; Schmidt, Walter; Krupp, Norbert; Lammer, Helmut; Kallio, Esa; Haukka, Harri

    2013-04-01

    Europlanet RI / NA2 Science Networking [1] focused on determining the major goals of current and future European planetary science, relating them to the Research Infrastructure that the Europlanet RI project [2] developed, and placing them in a more global context. NA2 also enhanced the ability of European planetary scientists to participate on the global scene with their own agenda-setting projects and ideas. The Networking Activity NA2 included five working groups, aimed at identifying key science issues and producing reference books on major science themes that will bridge the gap between the results of present and past missions and the scientific preparation of the future ones. Within the Europlanet RI project (2009-2012) the NA2 and NA2-WGs organized thematic workshops, an expert exchange program and training groups to improve the scientific impact of this Infrastructure. The principal tasks addressed by NA2 were: • Science activities in support to the optimal use of data from past and present space missions, involving the broad planetary science community beyond the "space club" • Science activities in support to the preparation of future planetary missions: Earth-based preparatory observations, laboratory studies, R&D on advanced instrumentation and exploration technologies for the future, theory and modeling etc. • Develop scientific activities, joint publications, dedicated meetings, tools and services, education activities, engaging the public and industries • Update science themes and addressing the two main scientific objectives • Prepare and support workshops of the International Space Science Institute (ISSI) in Bern and • Support Trans National Activities (TNAs), Joined Research Activities (JRAs) and the Integrated and Distributed Information Service (IDIS) of the Europlanet project These tasks were achieved by WG workshops organized by the NA2 working groups, by ISSI workshops and by an Expert Exchange Program. There were 17 official WG

  19. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    SciTech Connect

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmosphere during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.

  20. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    DOE PAGES

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less

  1. Ionic regulation of Na absorption in proximal colon: cation inhibition of electroneutral Na absorption

    SciTech Connect

    Sellin, J.H.; De Soignie, R.

    1987-01-01

    Active Na absorption (J/sub net//sup NA/) in rabbit proximal colon in vitro is paradoxically stimulated as (Na) in the bathing media is lowered with constant osmolarity. J/sub m..-->..s//sup Na/ increases almost linearly from 0 to 50 mM (Na)/sub 0/ but then plateaus and actually decreases from 50 to 140 mM (Na)/sub 0/, consistent with inhibition of an active transport process. Both lithium and Na are equally effective inhibitors of J/sub net//sup Na/, whereas choline and mannitol do not block the high rate of J/sub net//sup Na/ observed in decreased (Na)/sub 0/. Either gluconate or proprionate replacement of Cl inhibits J/sub net//sup Na/. J/sub net//sup Na/ at lowered (Na)/sub 0/ is electrically silent and is accompanied by increased Cl absorption; it is inhibited by 10/sup -3/ M amiloride and 10/sup -3/ theophylline but not by 10/sup -4/ M bumetanide. Epinephrine is equally effective at stimulating Na absorption at 50 and 140 mM (Na). Na gradient experiments are consistent with a predominantly serosal effect of the decreased (Na)/sub 0/. These results suggest that 1) Na absorption in rabbit proximal colon in vitro is stimulated by decreased (Na); 2) the effect is cation specific, both Na and Li blocking the stimulatory effect; 3) the transport is mediated by Na-H exchange and is Cl dependent but 4) is under different regulatory mechanisms than the epinephrine-sensitive Na-Cl cotransport previously described in proximal colon. Under the appropriate conditions, proximal colon absorbs Na extremely efficiently. Na-H exchange in this epithelium is cation inhibitable, either directly or by a secondary regulatory process.

  2. Single crystal growth of type I Na-Si clathrate by using Na-Sn flux

    NASA Astrophysics Data System (ADS)

    Morito, Haruhiko; Shimoda, Masashi; Yamane, Hisanori

    2016-09-01

    Single crystals of type I Na-Si clathrate, Na8Si46, were synthesized by heating Na, Na4Si4, and Na15Sn4 at 723 K under an Ar gas pressure of 104 Pa for 12 h. The single crystals having {110} habit planes grew up to 1.5 mm in size due to Na evaporation from a Na-Si-Sn melt with a starting compositional molar ratio of Na/Si/Sn=5.75:2:1.

  3. Deliquescence of NaCl-NaNO3 and KNO3-NaNO3 Salt Mixtures at 90C

    SciTech Connect

    Carroll, S; Craig, L; Wolery, T

    2003-12-29

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO3-H2O and KNO{sub 3}-NaNO{sub 3}-H{sub 2}O systems at 90 C to determine relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Model predictions agree with experimental results for the NaCl-NaNO{sub 3}-H{sub 2}O system, but underestimate relative humidity by as much as 8% and solution composition by as much as 50% in the KNO{sub 3}-NaNO{sub 3}-H{sub 2}O system.

  4. Compensatory regulation of Na+ absorption by Na+/H+ exchanger and Na+-Cl- cotransporter in zebrafish (Danio rerio)

    PubMed Central

    2013-01-01

    Introduction In mammals, internal Na+ homeostasis is maintained through Na+ reabsorption via a variety of Na+ transport proteins with mutually compensating functions, which are expressed in different segments of the nephrons. In zebrafish, Na+ homeostasis is achieved mainly through the skin/gill ionocytes, namely Na+/H+ exchanger (NHE3b)-expressing H+-ATPase rich (HR) cells and Na+-Cl- cotransporter (NCC)-expressing NCC cells, which are functionally homologous to mammalian proximal and distal convoluted tubular cells, respectively. The present study aimed to investigate whether or not the functions of HR and NCC ionocytes are differentially regulated to compensate for disruptions of internal Na+ homeostasis and if the cell differentiation of the ionocytes is involved in this regulation pathway. Results Translational knockdown of ncc caused an increase in HR cell number and a resulting augmentation of Na+ uptake in zebrafish larvae, while NHE3b loss-of-function caused an increase in NCC cell number with a concomitant recovery of Na+ absorption. Environmental acid stress suppressed nhe3b expression in HR cells and decreased Na+ content, which was followed by up-regulation of NCC cells accompanied by recovery of Na+ content. Moreover, knockdown of ncc resulted in a significant decrease of Na+ content in acid-acclimated zebrafish. Conclusions These results provide evidence that HR and NCC cells exhibit functional redundancy in Na+ absorption, similar to the regulatory mechanisms in mammalian kidney, and suggest this functional redundancy is a critical strategy used by zebrafish to survive in a harsh environment that disturbs body fluid Na+ homeostasis. PMID:23924428

  5. The hydrogen storage properties of Na decorated small boron cluster B6Na8

    NASA Astrophysics Data System (ADS)

    Tang, Chunmei; Wang, Zhiguo; Zhang, Xue; Wen, Ninghua

    2016-09-01

    The binding energy of the Na atoms to the hollow sites of the B6 cage is larger than the experimental cohesive energy of bulk Na, so the clustering of Na atoms can be avoided. The polarization interaction dominates the adsorption of H2 by the B6Na8 cluster. The Na-coated B6Na8sbnd B8sbnd B6Na8 complex with the dispersive Na atoms and four H2 molecules adsorbed per Na can serve as better building blocks of polymers than the (B6Na8)2 dimer. These findings suggest a new route to design cluster-assembled hydrogen storage materials based on sp2-terminated boron chains.

  6. Silicene for Na-ion battery applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jiajie; Schwingenschlögl, Udo

    2016-09-01

    Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received attention with respect to Na-ion batteries. In this context, freestanding silicene, a graphene-silicene-graphene heterostructure, and a graphene-silicene superlattice are investigated for possible application in Na-ion batteries, using first-principles calculations. The calculated Na capacities of 954 mAh/g for freestanding silicene and 730 mAh/g for the graphene-silicene superlattice (10% biaxial tensile strain) are highly competitive and potentials of \\gt 0.3 {{V}} against the Na{}+/Na potential exceed the corresponding value of graphite. In addition, the diffusion barriers are predicted to be \\lt 0.3 {eV}.

  7. The effect of Na vapor on the Na content of chondrules

    NASA Technical Reports Server (NTRS)

    Lewis, R. Dean; Lofgren, Gary E.; Franzen, Hugo F.; Windom, Kenneth E.

    1993-01-01

    Chondrules contain higher concentrations of volatiles (Na) than expected for melt droplets in the solar nebula. Recent studies have proposed that chondrules may have formed under non-canonical nebular conditions such as in particle/gas-rich clumps. Such chondrule formation areas may have contained significant Na vapor. To test the hypothesis of whether a Na-rich vapor would minimize Na volatilization reaction rates in a chondrule analog and maintain the Na value of the melt, experiments were designed where a Na-rich vapor could be maintained around the sample. A starting material with a melting point lower that typical chondrules was required to keep the logistics of working with Na volatilization from NaCl within the realm of feasibility. The Knippa basalt, a MgO-rich alkali olivine basalt with a melting temperature of 1325 +/- 5 C and a Na2O content of 3.05 wt%, was used as the chondrule analog. Experiments were conducted in a 1 atm, gas-mixing furnace with the fO2 controlled by a CO/CO2 gas mixture and fixed at the I-W buffer curve. To determine the extent of Na loss from the sample, initial experiments were conducted at high temperatures (1300 C - 1350 C) for duration of up to 72 h without a Na-rich vapor present. Almost all (up to 98%) Na was volatilized in runs of 72 h. Subsequent trials were conducted at 1330 C for 16 h in the presence of a Na-rich vapor, supplied by a NaCl-filled crucible placed in the bottom of the furnace. Succeeding Knudsen cell weight-loss mass-spectrometry analysis of NaCl determined the P(sub Na) for these experimental conditions to be in the 10(exp -6) atm range. This value is considered high for nebula conditions but is still plausible for non-canonical environments. In these trials the Na2O content of the glass was maintained or in some cases increased; Na2O values ranged from 2.62% wt to 4.37% wt. The Na content of chondrules may be controlled by the Na vapor pressure in the chondrule formation region. Most heating events capable

  8. Effect of colchicine on sensitivity of duck salt gland Na,K-ATPase to Na+.

    PubMed

    Yakushev, S S; Kumskova, E M; Rubtsov, A M; Lopina, O D

    2008-09-01

    Low molecular mass proteins of the FXYD family that affect the sensitivity of Na,K-ATPase to Na+ and K+ are known to be present in Na,K-ATPases in various tissues. In particular, in Na,K-ATPase from kidney a gamma-subunit (with electrophoretic mobility corresponding to molecular mass of about 10 kD) is present, and Na,K-ATPase preparations from heart contain phospholemman (electrophoretic mobility of this protein corresponds to molecular mass of 13-14 kD), which provides for the interaction of heart Na,K-ATPase with cytoskeletal microtubules. Disruption of microtubules by colchicine removes phospholemman from heart Na,K-ATPase preparations. The goal of the present study was to reveal a low molecular mass protein (probably a member of FXYD family) in preparation of Na,K-ATPase from duck salt glands. Immunoprecipitation of solubilized duck salt gland Na,K-ATPase using antibodies against alpha1-subunit results in the coprecipitation of a 13 kD protein with the Na,K-ATPase complex. Treatment of homogenate from duck salt glands with colchicine removes this protein from the purified preparation of Na,K-ATPase. Simultaneously, we observed a decrease in the sensitivity of Na,K-ATPase to Na+ at pH 6.5. However, colchicine treatment of homogenate from rabbit kidney does not affect either the sensitivity of Na,K-ATPase obtained from this homogenate to Na+ or the content of 10 kD protein (presumably gamma-subunit). The data suggest that phospholemman (or a similar member of the FXYD family) tightly interacts with Na,K-ATPase from duck salt glands and binds it to microtubules, simultaneously participating in the regulation of the sensitivity of Na,K-ATPase to Na+. PMID:18976215

  9. Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.

    1993-01-01

    Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.

  10. Maintaining the Na atmosphere of Mercury

    NASA Technical Reports Server (NTRS)

    Killen, Rosemary M.; Morgan, Thomas H.

    1993-01-01

    The possible sources of the Na atmosphere of Mercury are calculatively studied. The likely structure, composition, and temperature of the planet's upper crust is examined along with the probable flux of Na from depth by grain boundary diffusion and by Knudsen flow. The creation of fresh regolith is considered along with mechanisms for supplying Na from the surface to the exosphere. The implications of the calculations for the probable abundances in the regolith are discussed.

  11. Colonic H(+)-K(+)-ATPase in K(+) conservation and electrogenic Na(+) absorption during Na(+) restriction.

    PubMed

    Spicer, Z; Clarke, L L; Gawenis, L R; Shull, G E

    2001-12-01

    Upregulation of the colonic H(+)-K(+)- ATPase (cHKA) during hyperaldosteronism suggests that it functions in both K(+) conservation and electrogenic Na(+) absorption in the colon when Na(+)-conserving mechanisms are activated. To test this hypothesis, wild-type (cHKA(+/+)) and cHKA-deficient (cHKA(-/-)) mice were fed Na(+)-replete and Na(+)-restricted diets and their responses were analyzed. In both genotypes, Na(+) restriction led to reduced plasma Na(+) and increased serum aldosterone, and mRNAs for the epithelial Na(+) channel (ENaC) beta- and gamma-subunits, channel-inducing factor, and cHKA were increased in distal colon. Relative to wild-type controls, cHKA(-/-) mice on a Na(+)-replete diet had elevated fecal K(+) excretion. Dietary Na(+) restriction led to increased K(+) excretion in knockout but not in wild-type mice. The amiloride-sensitive, ENaC-mediated short-circuit current in distal colon was significantly reduced in knockout mice maintained on either the Na(+)-replete or Na(+)-restricted diet. These results demonstrate that cHKA plays an important role in K(+) conservation during dietary Na(+) restriction and suggest that cHKA-mediated K(+) recycling across the apical membrane is required for maximum electrogenic Na(+) absorption. PMID:11705741

  12. Ionic dependence of active Na-K transport: "clamping" of cellular Na+ with monensin.

    PubMed

    Haber, R S; Pressley, T A; Loeb, J N; Ismail-Beigi, F

    1987-07-01

    The Na+ ionophore monensin was used to study the Na+- and K+-dependence of ouabain-inhibitable 86Rb+ uptake in ARL 15 cells, a rat liver cell line. Graded concentrations of monensin rapidly induced incremental elevations of cellular Na+ that were stable for up to 2 h. In experiments in which cellular Na+ was thus "clamped" at various levels, the activation curve for ouabain-inhibitable 86Rb+ uptake as a function of intracellular Na+ was found to be steepest near basal Na+ levels (Hill coefficient approximately equal to 2.4), indicating that these cells can respond to relatively large changes in passive Na+ entry by increasing the race of Na-K pump function with only minimal increases in cellular Na+. Exposure of cells to monensin also permitted examination of the extracellular-K+ dependence of ouabain-inhibitable 86Rb+ uptake in the presence of saturating intracellular Na+ and yielded a Hill coefficient of approximately 1.5. The rate of ATP hydrolysis calculated from measurements of the maximal rate of ouabain-inhibitable 86Rb+ uptake in intact cells was similar to the enzymatic Vmax of the Na+-K+-ATPase in cell lysates, suggesting that the Na+-K+-ATPase activity in these broken-cell preparations closely reflects the functional transport capacity of the Na-K pump.

  13. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. |; Rosener, B.

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  14. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. . Dept. of Computer Science Oak Ridge National Lab., TN ); Rosener, B. . Dept. of Computer Science)

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host na-net.ornl.gov'' at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message send index'' to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user's perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  15. Painful Na-channelopathies: an expanding universe.

    PubMed

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic.

  16. NaHCO3 and NaC1 tolerance in chronic renal failure.

    PubMed

    Husted, F C; Nolph, K D; Maher, J F

    1975-08-01

    In patients with chronic renal failure, NaHCO3 therapy may correct or prevent acidemia. It has been proposed that the NaHCO3 required will not result in clinically significant Na retention comparable to that from similar increases in NaC1 intake. In each of ten patients with chronic renal failure, creatinine clearance (Ccr) range 2.5-16.8 ml/min, on an estimated 10-meq Na and C1 diet, electrolyte excretion was compared on NaHCO3 vs NaC1 supplements of 200 meq/day. Periods of NaHCO3 and NaC1 (in alternate order for successive patients) lasted 4 days, separated by reequilibration to base-line weight. Mean +/- SEM excretion (ex) of Na, C1, and HCO3 and deltaCcr and deltaweight (day 4-1) are compared below for the 4th day of NaC1 vs. NaHCO3 intake. Mean Ccr +/-SEM on day 4 of NaC1 and NaHCO3 were 10.8 +/-1.6 and 9.0 +/-1.4 ml/min, respectively (P less than 0.02). Mean systolic blood pressure (but not diastolic) increased significantly on NaC1 (P less than 0.05). No significant blood pressure changes were seen on NaHCO3. Net positive HCO3 balance occurred on NaHCO3 as indicated above and reflected a rise in mean serum HCO3 from 19 to 30 meq/liter (day 1 vs. 4) (P less than 0.01). Mechanisms for the greater excretion of Na on NaHCO3 may relate to C1 wasting as noted above on low C1 intake and limited HCO3 reabsorptive capacity. Thus, Na excretion by day 4 was greater on NaHCO3 than on NaHCO3 did Na excretion near intake (210 meq/day).

  17. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

    PubMed Central

    Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

    2015-01-01

    This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291

  18. Reduced Na+ uptake in the NaCl-hypersensitive sos1 mutant of Arabidopsis thaliana.

    PubMed Central

    Ding, L; Zhu, J K

    1997-01-01

    Sos1 is an Arabidopsis thaliana mutant with > 20 times higher sensitivity toward Na+ inhibition due to a defective high-affinity potassium-uptake system. We report here that sos1 accumulates less Na+ than the wild type in response to NaCl stress. The Na+ contents in sos1 seedlings exposed to 25 mM NaCl for 2 or more d are about 43% lower than those in the wild type. When assayed at 20 mM external NaCl, sos1 seedlings pretreated with low potassium have 32% lower Na+ uptake than the wild type. However, little difference in Na+ uptake could be measured when the seedlings were not pretreated with low potassium. Low-potassium treatment was shown to induce high-affinity potassium-uptake activity in Arabidopsis seedlings. No substantial difference in Na+ efflux between sos1 and the wild type was detected. The results show that the reduced Na+ accumulation in sos1 is due to a lower Na+ influx rate. Therefore, the sos1 mutation appears to disrupt low-affinity Na+ uptake in addition to its impairment of high-affinity K+ uptake. PMID:9085573

  19. Inelastic processes in Na+-Ne, Na+-Ar, Ne+-Na, and Ar+-Na collisions in the energy range 0.5-14 keV

    NASA Astrophysics Data System (ADS)

    Lomsadze, R. A.; Gochitashvili, M. R.; Kezerashvili, R. Ya.

    2015-12-01

    Absolute cross sections for charge-exchange, ionization, and excitation in Na+-Ne and Na+-Ar collisions were measured in the ion energy range 0.5 -10 keV using a refined version of a capacitor method and collision and optical spectroscopy methods simultaneously in the same experimental setup. Ionization cross sections for Ne+-Na and Ar+-Na collisions are measured at energies of 2 -14 keV using a crossed-beam spectroscopy method. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. For the charge-exchange process in Na+-Ar collisions two nonadiabatic regions are revealed and mechanisms responsible for these regions are explained. Structural peculiarity on the excitation function for the resonance lines of argon atoms in Na+-Ar collisions are observed and the possible mechanisms of this phenomenon are explored. The measured ionization cross sections for Na+-Ne and Ne+-Na collisions in conjunction with the Landau-Zener formula are used to determine the coupling matrix element and transition probability in a region of pseudocrossing of the potential curves.

  20. Regulation of Na+ fluxes in plants

    PubMed Central

    Maathuis, Frans J. M.; Ahmad, Izhar; Patishtan, Juan

    2014-01-01

    When exposed to salt, every plant takes up Na+ from the environment. Once in the symplast, Na+ is distributed within cells and between different tissues and organs. There it can help to lower the cellular water potential but also exert potentially toxic effects. Control of Na+ fluxes is therefore crucial and indeed, research shows that the divergence between salt tolerant and salt sensitive plants is not due to a variation in transporter types but rather originates in the control of uptake and internal Na+ fluxes. A number of regulatory mechanisms has been identified based on signaling of Ca2+, cyclic nucleotides, reactive oxygen species, hormones, or on transcriptional and post translational changes of gene and protein expression. This review will give an overview of intra- and intercellular movement of Na+ in plants and will summarize our current ideas of how these fluxes are controlled and regulated in the early stages of salt stress. PMID:25278946

  1. High NA Nicrostepper Final Optical Design Report

    SciTech Connect

    Hudyma, R

    1999-09-24

    The development of a new EUV high NA small-field exposure tool has been proposed for obtaining mask defect printability data in a timeframe several years before beta-tools are available. The imaging system for this new Micro-Exposure Tool (MET), would have a numerical aperture (NA) of about 0.3, similar to the NA for a beta-tool, but substantially larger than the 0.10 NA for the Engineering Test Stand (ETS) and 0.088 NA for the existing 10x Microstepper. This memorandum discusses the development and summarizes the performance of the camera for the MET and includes a listing of the design prescription, detailed analysis of the distortion, and analysis demonstrating the capability to resolution 30 nm features under the conditions of partially coherent illumination.

  2. Negative electrodes for Na-ion batteries.

    PubMed

    Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

    2014-08-01

    Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

  3. Na-doped optical Germanium bulk crystals

    NASA Astrophysics Data System (ADS)

    Pekar, G. S.; Singaevsky, A. F.

    2012-09-01

    In an effort to develop a material for infrared (IR) optics with improved parameters, bulk crystals of optical germanium doped with Na have been first grown and studied. Single-crystalline and coarse-crystalline Ge:Na boules of different shapes and dimensions, up to 10 kg by weight, have been grown. Sodium was incorporated into the Ge crystal during the crystal growing from the melt. Despite the fact that Na contamination in the source material was not strictly controlled, the density of Na in the grown crystals determined by the neutron activation analysis as well as by the glow discharge mass spectrometry did not exceed 1015 cm-3. Just this value may be supposed to be close to the solubility limit of Na incorporated in Ge in the course of bulk crystal growth. A first demonstration of donor behavior of Na in bulk Ge crystals is made by means of a thermoelectric type of testing. An interstitial location of Na impurity has been verified by experiments on donor drift in the dc electric field. The crystals are grown with free electron density in the range from 5ṡ1013 to 4ṡ1014 cm-3 which is optimal for using Ge crystals as an optical material for fabricating passive elements of the IR technique. A comparison between the properties of Ge:Na crystals and Ge crystals doped with Sb, a conventional impurity in optical germanium, grown under the same technological conditions and from the same intrinsic Ge as a source material, revealed a number of advantages of Ge:Na crystals; among them, the higher transparency in the IR region, smaller radiation scattering and higher regular optical transmission, lower dislocation density, more uniform distribution of electrical and optical characteristics over the crystal volume, the identity of optical parameters in the single-crystalline, and coarse-crystalline boules. No degradation of optical elements fabricated from Ge:Na crystals was detected in the course of their commercial application, starting from 1998.

  4. Polarization dependence of Na/emph>+Na/emph> associative ionization revisited

    NASA Astrophysics Data System (ADS)

    Meijer, H. A. J.; Meulen, H. P. V. D.; Morgenstern, R.; Hertel, I. V.; Meyer, E.; Schmidt, H.; Witte, R.

    1986-02-01

    The dependence of the associative ionization process Na 3 2P3/2+Na 3 2P3/2-->Na2 ++e- on the polarization of the laser light used for Na excitation was independently investigated in Utrecht and Berlin. The purpose of this paper is to clarify discrepancies between earlier experimental results of Kircz, Morgenstern, and Nienhuis, on one hand, and Rothe, Theyunni, Reck, and Tung on the other hand. The new results confirm in general the data of Kircz, Morgenstern, and Nienhuis, and also indicate a dependence of the anisotropy ratios on the relative velocity of the interacting Na* atoms.

  5. The NA62 RICH detector

    SciTech Connect

    Cassese, A.

    2011-07-01

    The NA62 experiment is designed to measure the very rare kaon decay K{sup +} {yields} {pi}{sup +} at the CERN SPS with a 10% accuracy. The Standard Model prediction for the Branching Ratio is (8.5 {+-} 0.7) x 10{sup -11}. One of the challenging aspect of the experiment is the suppression of the K{sup +} {yields} {mu}{sup +} v{sub {mu}} background at the 10{sup -12} level. To satisfy this requirement a Ring Imaging Cherenkov Detector (RICH), able to separate {pi}{sup {+-}} from {mu}{sup {+-}} in the momentum range between 15 and 35 GeV/c, with a {mu}, rejection factor better than 10{sup -2}, is needed. The RICH must also have a time resolution of about 100 ps to disentangle accidental time associations of beam particles with pions. The RICH will have a very long focal length (17 m) and will be filled with Ne gas at atmospheric pressure. Two test beams were held at CERN in 2007 and 2009 with a RICH prototype. The results of the two test beams will be presented: the {mu}, mis-identification probability is found to be about 0.7% and the time resolution better than 100 ps in the whole momentum range. (authors)

  6. Na-site substitution effects on the thermoelectric properties of NaCo2O4

    NASA Astrophysics Data System (ADS)

    Kawata, T.; Iguchi, Y.; Itoh, T.; Takahata, K.; Terasaki, I.

    1999-10-01

    The resistivity and thermopower of Na1+xCo2O4 and Na1.1-xCaxCo2O4 are measured and analyzed. In Na1+xCo2O4, whereas the resistivity increases with x, the thermopower is nearly independent of x. This suggests that the excess Na is unlikely to supply carriers, and decreases effective conduction paths in the sample. In Na1.1-xCaxCo2O4, the resistivity and the thermopower increase with x, and the Ca2+ substitution for Na+ reduces the majority carriers in NaCo2O4. This means that they are holes, which is consistent with the positive sign of the thermopower. Strong correlation in this compound is evidenced by the peculiar temperature dependence of the resistivity.

  7. Extracellular Na+ levels regulate formation and activity of the NaX/alpha1-Na+/K+-ATPase complex in neuronal cells

    PubMed Central

    Berret, Emmanuelle; Smith, Pascal Y.; Henry, Mélaine; Soulet, Denis; Hébert, Sébastien S.; Toth, Katalin; Mouginot, Didier; Drolet, Guy

    2014-01-01

    MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as sensors of extracellular sodium concentration ([Na+]out). The mechanism underlying Na+-sensing involves Na+-flow through the NaX channel, directly regulated by the Na+/K+-ATPase α1-isoform which controls Na+-influx by modulating channel permeability. Together, these two partners form a complex involved in the regulation of intracellular sodium ([Na+]in). Here we aim to determine whether environmental changes in Na+ could actively modulate the NaX/Na+/K+-ATPase complex activity. We investigated the complex activity using patch-clamp recordings from rat MnPO neurons and Neuro2a cells. When the rats were fed with a high-salt-diet, or the [Na+] in the culture medium was increased, the activity of the complex was up-regulated. In contrast, drop in environmental [Na+] decreased the activity of the complex. Interestingly under hypernatremic condition, the colocalization rate and protein level of both partners were up-regulated. Under hyponatremic condition, only NaX protein expression was increased and the level of NaX/Na+/K+-ATPase remained unaltered. This unbalance between NaX and Na+/K+-ATPase pump proportion would induce a bigger portion of Na+/K+-ATPase-control-free NaX channel. Thus, we suggest that hypernatremic environment increases NaX/Na+/K+-ATPase α1-isoform activity by increasing the number of both partners and their colocalization rate, whereas hyponatremic environment down-regulates complex activity via a decrease in the relative number of NaX channels controlled by the pump. PMID:25538563

  8. Gasotransmitters: novel regulators of epithelial na(+) transport?

    PubMed

    Althaus, Mike

    2012-01-01

    The vectorial transport of Na(+) across epithelia is crucial for the maintenance of Na(+) and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na(+) transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na(+) transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H(2)S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na(+) transport across epithelia. This review will summarize the available data concerning NO, CO, and H(2)S dependent regulation of epithelial Na(+) transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na(+) transport biology.

  9. Myocardial Na,K-ATPase: Clinical aspects

    PubMed Central

    Kjeldsen, Keld

    2003-01-01

    The specific binding of digitalis glycosides to Na,K-ATPase is used as a tool for Na,K-ATPase quantification with high accuracy and precision. In myocardial biopsies from patients with heart failure, total Na,K-ATPase concentration is decreased by around 40%; a correlation exists between a decrease in heart function and a decrease in Na,K-ATPase concentration. During digitalization, around 30% of remaining pumps are occupied by digoxin. Myocardial Na,K-ATPase is also influenced by other drugs used for the treatment of heart failure. Thus, potassium loss during diuretic therapy has been found to reduce myocardial Na,K-ATPase, whereas angiotensin-converting enzyme inhibitors may stimulate Na,K pump activity. Furthermore, hyperaldosteronism induced by heart failure has been found to decrease Na,K-ATPase activity. Accordingly, treatment with the aldosterone antagonist, spironolactone, may also influence Na,K-ATPase activity. The importance of Na,K pump modulation with heart disease, inhibition in digitalization and other effects of medication should be considered in the context of sodium, potassium and calcium regulation. It is recommended that digoxin be administered to heart failure patients who, after institution of mortality-reducing therapy, still have heart failure symptoms, and that the therapy be continued if symptoms are revealed or reduced. Digitalis glycosides are the only safe inotropic drugs for oral use that improve hemodynamics in heart failure. An important aspect of myocardial Na,K pump affection in heart disease is its influence on extracellular potassium (Ke) homeostasis. Two important aspects should be considered: potassium handling among myocytes, and effects of potassium entering the extracellular space of the heart via the bloodstream. It should be noted that both of these aspects of Ke homeostasis are affected by regulatory aspects, eg, regulation of the Na,K pump by physiological and pathophysiological conditions, as well as by medical

  10. Characteristics and pharmacological regulation of epithelial Na+ channel (ENaC) and epithelial Na+ transport.

    PubMed

    Marunaka, Yoshinori

    2014-01-01

    Epithelial Na(+) transport participates in control of various body functions and conditions: e.g., homeostasis of body fluid content influencing blood pressure, control of amounts of fluids covering the apical surface of alveolar epithelial cells at appropriate levels for normal gas exchange, and prevention of bacterial/viral infection. Epithelial Na(+) transport via the transcellular pathway is mediated by the entry step of Na(+) across the apical membrane via Epithelial Na(+) Channel (ENaC) located at the apical membrane, and the extrusion step of Na(+) across the basolateral membrane via the Na(+),K(+)-ATPase located at the basolateral membrane. The rate-limiting step of the epithelial Na(+) transport via the transcellular pathway is generally recognized to be the entry step of Na(+) across the apical membrane via ENaC. Thus, up-/down-regulation of ENaC essentially participates in regulatory systems of blood pressure and normal gas exchange. Amount of ENaC-mediated Na(+) transport is determined by the number of ENaCs located at the apical membrane, activity (open probability) of individual ENaC located at the apical membrane, single channel conductance of ENaC located at the apical membrane, and driving force for the Na(+) entry via ENaCs across the apical membrane. In the present review article, I discuss the characteristics of ENaC and how these factors are regulated.

  11. Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

    PubMed

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

    2016-03-01

    The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect

  12. Dependence of Na-K pump current on internal Na+ in mammalian cardiac myocytes.

    PubMed

    Mogul, D J; Singer, D H; Ten Eick, R E

    1990-08-01

    Na-K pump current (Ipump) is a function of the intracellular Na+ concentration [( Na+]i). We examined the quantitative relationship between Ipump and [Na+]i in isolated guinea pig ventricular myocytes under steady-state conditions. [Na+]i was controlled and "clamped" at several selected concentrations using wide-tipped pipette microelectrodes, and membrane current was measured using the whole cell patch voltage-clamp technique. Ipump generated at a holding potential of -40 mV was determined by measuring the change in steady-state holding current before and during exposure to dihydroouabain (1 mM); Ipump was measured at 11 levels of [Na+]i ranging from 0 to 80 mM (n = 63) with only one measurement per cell and normalized to cell capacitance to account for differences between myocytes in sarcolemmal surface area. Ipump exhibited a nonlinear dependence on [Na+]i; a Hill analysis of the relationship yielded a half-maximal [Na+]i for pump stimulation of 43.2 mM and a Hill coefficient of 1.53. An alternative analysis of the experimental data was performed assuming that occupation of three internal binding sites by Na+ is required for enzyme turnover. Regression analysis gave the best fit when only two different binding affinities (KD) are postulated. The values are KD1 = 1 mM, KD2 = KD3 = 29 mM. From the analysis using the latter model, the level of [Na+]i at which Ipump saturated closely approximated the theoretical saturation level calculated from published estimates of pump turnover rate and density. The maximal sensitivity of the Na-K pump to changes in [Na+]i occurs when internal [Na+] is within the range for the normal resting physiological level. PMID:2167023

  13. [Na+/H+- and Na+/Na+-countertransport in human, rabbit, and rat erythrocytes: evidence for the existence of two independent ion-transporting systems].

    PubMed

    Orlov, S N; Kuznetsov, S R; Kolosova, I A; Makarov, V L

    1994-05-01

    The activity and regulatory features of the Na+/H(+)- and Na+/Na(+)-exchange were studied in human, rabbit and rat red blood cells. No basal activity of the Na+/H(+)-exchange (the amyloride-inhibited component of the 22Na+ influx) in erythrocytes of these species was observed. The rate of 22Na+ influx increased rapidly when the experiments were carried out on acid-loaded cells in an alkaline (pH0 = 8.0) incubation medium (delta mu H(+)-induced Na+/H(+)-exchange). The ratio of delta mu H(+)-induced Na+/H(+)-exchange activities in human, rabbit and rat red blood cells was 1.0 : 1.1 : 2.3, respectively, whereas that of the Na+/Na(+)-exchange activities (the phloretin-inhibited component of the 22Na+ influx) in erythrocytes of these species was 1.0 : 4.6 : 0.2. The osmotic shrinkage of rat and rabbit erythrocytes led to the stimulation of the Na+/H(+)- (but not Na+/Na+) exchange. Amyloride (1 mM) inhibited the shrinkage-induced 22Na+ entry as well as the delta mu H(+)-induced 22Na+ entry--by 95 and 10-20%, respectively. Heat treatment (10 min, 49-51 degrees C), disturbing the membrane cytoskeleton suppressed both the shrinkage-induced activation and the delta mu H(+)-induced activation of the Na+/H(+)-exchange. The data obtained indicate that the both transport systems are mediated by two distinct transport carriers. It may be suggested that the delta mu H(+)-induced Na+/H(+)-exchange, on the one hand, and the shrinkage-induced Na+/H(+)-exchange, on the other, are mediated by two different Na+/H(+)-exchanger subtypes. PMID:8043690

  14. Anamorphic high-NA EUV lithography optics

    NASA Astrophysics Data System (ADS)

    Migura, Sascha; Kneer, Bernhard; Neumann, Jens Timo; Kaiser, Winfried; van Schoot, Jan

    2015-09-01

    EUV lithography (EUVL) for a limit resolution below 8 nm requires the numerical aperture (NA) of the projection optics to be larger than 0.50. For such a high-NA optics a configuration of 4x magnification, full field size of 26 x 33 mm² and 6'' mask is not feasible anymore. The increased chief ray angle and higher NA at reticle lead to non-acceptable mask shadowing effects. These shadowing effects can only be controlled by increasing the magnification, hence reducing the system productivity or demanding larger mask sizes. We demonstrate that the best compromise in imaging, productivity and field split is a so-called anamorphic magnification and a half field of 26 x 16.5 mm² but utilizing existing 6'' mask infrastructure. We discuss the optical solutions for such anamorphic high-NA EUVL.

  15. Searches for New Physics at NA62

    NASA Astrophysics Data System (ADS)

    Palladino, Vito

    2011-10-01

    We present the latest NA62 results in the search for physics beyond Standard Model (SM). NA62 aims to have indirect evidences of new physics, measuring rare K decays. NA62 phase I took place in 2007 when we collected data in order to measure the ratio RK = Ke2/Kμ2 (were Kl2 means K → lνl) at few per mill level. A brief experimental layout description will be followed by analysis strategy and preliminary results. The last part of present paper will be devoted to the description of NA62 phase II, which has the main goal of measuring the ultra-rare K -> π ^ + ν bar ν decay Branching Ratio.

  16. Nanosegregation in Na2C60

    SciTech Connect

    Klupp, G.; Kamaras, K.; Matus, P.; Kiss, L.F.; Kovats, E.; Pekker, S.; Nemes, N.M.; Quintavalle, D.; Janossy, A.

    2005-09-27

    There is continuous interest in the nature of alkali metal fullerides containing C{sub 60}{sup 4-} and C{sub 60}{sup 2-}, because these compounds are believed to be nonmagnetic Mott-Jahn-Teller insulators. This idea could be verified in the case of A4C60, but Na2C60 is more controversial. By comparing the results of infrared spectroscopy and X-ray diffraction, we found that Na2C60 is segregated into 3-10 nm large regions. The two main phases of the material are insulating C60 and metallic Na3C60. We found by neutron scattering that the diffusion of sodium ions becomes faster on heating. Above 470 K Na2C60 is homogeneous and we show IR spectroscopic evidence of a Jahn-Teller distorted C{sub 60}{sup 2-} anion.

  17. Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C

    SciTech Connect

    Carroll, S A; Craig, L; Wolery, T J

    2004-10-20

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.

  18. Elastic Coulomb breakup of 34Na

    NASA Astrophysics Data System (ADS)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  19. HCO3(-)-coupled Na+ influx is a major determinant of Na+ turnover and Na+/K+ pump activity in rat hepatocytes

    SciTech Connect

    Fitz, J.G.; Lidofsky, S.D.; Weisiger, R.A.; Xie, M.H.; Cochran, M.; Grotmol, T.; Scharschmidt, B.F. )

    1991-05-01

    Recent studies in hepatocytes indicate that Na(+)-coupled HCO3- transport contributes importantly to regulation of intracellular pH and membrane HCO3- transport. However, the direction of net coupled Na+ and HCO3- movement and the effect of HCO3- on Na+ turnover and Na+/K+ pump activity are not known. In these studies, the effect of HCO3- on Na+ influx and turnover were measured in primary rat hepatocyte cultures with 22Na+, and (Na+)i was measured in single hepatocytes using the Na(+)-sensitive fluorochrome SBFI. Na+/K+ pump activity was measured in intact perfused rat liver and hepatocyte monolayers as Na(+)-dependent or ouabain-suppressible 86Rb uptake, and was measured in single hepatocytes as the effect of transient pump inhibition by removal of extracellular K+ on membrane potential difference (PD) and (Na+)i. In hepatocyte monolayers, HCO3- increased 22Na+ entry and turnover rates by 50-65%, without measurably altering 22Na+ pool size or cell volume, and HCO3- also increased Na+/K+ pump activity by 70%. In single cells, exposure to HCO3- produced an abrupt and sustained rise in (Na+)i from approximately 8 to 12 mM. Na+/K+ pump activity assessed in single cells by PD excursions during transient K+ removal increased congruent to 2.5-fold in the presence of HCO3-, and the rise in (Na+)i produced by inhibition of the Na+/K+ pump was similarly increased congruent to 2.5-fold in the presence of HCO3-. In intact perfused rat liver, HCO3- increased both Na+/K+ pump activity and O2 consumption. These findings indicate that, in hepatocytes, net coupled Na+ and HCO3- movement is inward and represents a major determinant of Na+ influx and Na+/K+ pump activity. About half of hepatic Na+/K+ pump activity appears dedicated to recycling Na+ entering in conjunction with HCO3- to maintain (Na+)i within the physiologic range.

  20. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes.

    PubMed

    Hegyi, Bence; Bányász, Tamás; Shannon, Thomas R; Chen-Izu, Ye; Izu, Leighton T

    2016-09-20

    In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes. PMID:27653489

  1. Interaction of NaCl(g) and HCl(g) with condensed NA2SO4

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.; Miller, R. A.

    1977-01-01

    The interaction of Na2SO4(l) with NaCl(g), HCl(g) and H2O(g) was studied in atmospheric pressure flowing air and oxygen at Na2SO4(l) temperatures of 900 and 1000 C. Thermomicrogravimetric and high pressure mass spectrometric sampling techniques were used. Experimental results establish that previously reported enhanced rates of weight loss of Na2SO4(l) in the presence of NaCl(g) are due to the reaction: Na2SO4(c) + 2HCl(g) = 2NaCl(g) + SO2(g) + H2O(g) + 1/2O2(g) being driven to the right in flowing gas systems. The HCl(g) is the product of hydrolysis of NaCl caused by small but significant amounts of H2O(g) present in the system. Thermochemical calculations are used to show that even with sub-ppm levels of H2O(g) present, significant quantities of HCl(g) are produced.

  2. Direct Measurement of ^21Na+α Stellar Reaction

    NASA Astrophysics Data System (ADS)

    Binh Dam, Nguyen; Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Hashimoto, T.; Kahl, D.; Kubono, S.; Le, H. K.; Nguyen, T. T.; Iwasa, N.; Kume, N.; Kato, S.; Teranishi, T.

    2009-10-01

    Nucleosynthesis of ^22Na is an interesting subject because of possible γ-ray observation and isotopic anomalies in presolar grain. ^22Na would have been mainly produced in the NeNa cycle. At high temperature conditions, ^21Na(α,p)^24Mg reaction could play a significant role to make flow from the NeNa cycle to the next MgAl cycle and beyond. Clearly, the ^21Na(α,p)^24Mg stellar reaction would bypass ^22Na, resulting in reduction of ^22Na production, therefore, it is strongly coupled to the Ne-E problem. It could be also important to understand the early stage of the rp-process. Experiment was performed using a 39 MeV ^21Na radioactive beam obtained by the CNS Radio Isotope Beam separator CRIB of the University of Tokyo. Both protons and alphas were measured from α+^21Na scattering with a thick ^4He gas target.

  3. Functional coupling of renal K+ and Na+ handling causes high blood pressure in Na+ replete mice

    PubMed Central

    Vitzthum, Helga; Seniuk, Anika; Schulte, Laura Helene; Müller, Maxie Luise; Hetz, Hannah; Ehmke, Heimo

    2014-01-01

    A network of kinases, including WNKs, SPAK and Sgk1, is critical for the independent regulation of K+ and Na+ transport in the distal nephron. Angiotensin II is thought to act as a key hormone in orchestrating these kinases to switch from K+ secretion during hyperkalaemia to Na+ reabsorption during intravascular volume depletion, thus keeping disturbances in electrolyte and blood pressure homeostasis at a minimum. It remains unclear, however, how K+ and Na+ transport are regulated during a high Na+ intake, which is associated with suppressed angiotensin II levels and a high distal tubular Na+ load. We therefore investigated the integrated blood pressure, renal, hormonal and gene and protein expression responses to large changes of K+ intake in Na+ replete mice. Both low and high K+ intake increased blood pressure and caused Na+ retention. Low K+ intake was accompanied by an upregulation of the sodium-chloride cotransporter (NCC) and its activating kinase SPAK, and inhibition of NCC normalized blood pressure. Renal responses were unaffected by angiotensin AT1 receptor antagonism, indicating that low K+ intake activates the distal nephron by an angiotensin-independent mode of action. High K+ intake was associated with elevated plasma aldosterone concentrations and an upregulation of the epithelial sodium channel (ENaC) and its activating kinase Sgk1. Surprisingly, high K+ intake increased blood pressure even during ENaC or mineralocorticoid receptor antagonism, suggesting the contribution of aldosterone-independent mechanisms. These findings show that in a Na+ replete state, changes in K+ intake induce specific molecular and functional adaptations in the distal nephron that cause a functional coupling of renal K+ and Na+ handling, resulting in Na+ retention and high blood pressure when K+ intake is either restricted or excessively increased. PMID:24396058

  4. NaCd excimer emission bands

    NASA Astrophysics Data System (ADS)

    Pichler, G.; Veža, D.; Fijan, D.

    1988-06-01

    The analysis of the visible spectrum of a high pressure sodium lamp filled with sodium, cadium and xenon revealed the existence of NaCd excimer spectral features. These are four red satellite bands at 691, 697, 709 and 726.5 nm and diffuse bands peaking at 479.1 and 484.3 nm. Both spectral phenomena are related to those found earlier for the NaHg system. An interpretation of the red satellite bands origin is given in terms of a qualitative model for the four lowest potential curves of the NaCd excimer. In this model the essential feature is the avoided crossing between B 2∑ 1/2 and A 2∏ 1/2 electronic states, which causes a complex structure of the satellite bands in the very far red wing of the sodium D lines broadened by cadmium.

  5. Targeting voltage gated sodium channels NaV1.7, Na V1.8, and Na V1.9 for treatment of pathological cough.

    PubMed

    Muroi, Yukiko; Undem, Bradley J

    2014-02-01

    Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1-NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough.

  6. Concentration dependence of Li+/Na+ diffusion in manganese hexacyanoferrates

    NASA Astrophysics Data System (ADS)

    Takachi, Masamitsu; Fukuzumi, Yuya; Moritomo, Yutaka

    2016-06-01

    Manganese hexacyanoferrates (Mn-HCFs) with a jungle-gym-type structure are promising cathode materials for Li+/Na+ secondary batteries (LIBs/SIBs). Here, we investigated the diffusion constants D Li/D Na of Li+/Na+ against the Li+/Na+ concentration x Na/x Li and temperature (T) of A 1.32Mn[Fe(CN)6]0.833.6H2O (A = Li and Na). We evaluated the activation energy E\\text{a}\\text{Li}/E\\text{a}\\text{Na} of D Li/D Na against x Na/x Li. We found that E\\text{a}\\text{Na} steeply increases with x Na from 0.41 eV at x Na = 0.69 to 0.7 eV at 1.1. The increase in E\\text{a}\\text{Na} is ascribed to the occupancy effect of the Na+ site. The increase in E\\text{a}\\text{Li} is suppressed, probably because the number of Li+ sites is three times that of Na+ sites.

  7. Crystal structure of a Na+-bound Na+,K+-ATPase preceding the E1P state.

    PubMed

    Kanai, Ryuta; Ogawa, Haruo; Vilsen, Bente; Cornelius, Flemming; Toyoshima, Chikashi

    2013-10-10

    Na(+),K(+)-ATPase pumps three Na(+) ions out of cells in exchange for two K(+) taken up from the extracellular medium per ATP molecule hydrolysed, thereby establishing Na(+) and K(+) gradients across the membrane in all animal cells. These ion gradients are used in many fundamental processes, notably excitation of nerve cells. Here we describe 2.8 Å-resolution crystal structures of this ATPase from pig kidney with bound Na(+), ADP and aluminium fluoride, a stable phosphate analogue, with and without oligomycin that promotes Na(+) occlusion. These crystal structures represent a transition state preceding the phosphorylated intermediate (E1P) in which three Na(+) ions are occluded. Details of the Na(+)-binding sites show how this ATPase functions as a Na(+)-specific pump, rejecting K(+) and Ca(2+), even though its affinity for Na(+) is low (millimolar dissociation constant). A mechanism for sequential, cooperative Na(+) binding can now be formulated in atomic detail. PMID:24089211

  8. Na+/K+-ATPase: Activity and inhibition

    NASA Astrophysics Data System (ADS)

    Čolović, M.; Krstić, D.; Krinulović, K.; Momić, T.; Savić, J.; Vujačić, A.; Vasić, V.

    2009-09-01

    The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl2DMSO2], [AuCl4]-, [PdCl4]2-, [PdCl(dien)]+, [PdCl(Me4dien)]+), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+), and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed.

  9. Na+ Inhibits the Epithelial Na+ Channel by Binding to a Site in an Extracellular Acidic Cleft*

    PubMed Central

    Kashlan, Ossama B.; Blobner, Brandon M.; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R.

    2015-01-01

    The epithelial Na+ channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na+, Cl−, protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na+ concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na+ binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na+. Mutations at selected sites altered the cation inhibitory preference to favor Li+ or K+ rather than Na+. Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na+. Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  10. Study on Na layer response to geomagnetic activities based on Odin/OSIRIS Na density data

    NASA Astrophysics Data System (ADS)

    Tsuda, Takuo; Nakamura, Takuji; Hedin, Jonas; Gumbel, Jorg; Hosokawa, Keisuke; Ejiri, Mitsumu K.; Nishiyama, Takanori; Takahashi, Toru

    2016-07-01

    The Na layer is normally distributed from 80 to 110 km, and the height range is corresponding to the ionospheric D and E region. In the polar region, the energetic particles precipitating from the magnetosphere can often penetrate into the E region and even into the D region. Thus, the influence of the energetic particles to the Na layer is one of interests in the aspect of the atmospheric composition change accompanied with the auroral activity. There are several previous studies in this issue. For example, recently, we have reported an initial result on a clear relationship between the electron density increase (due to the energetic particles) and the Na density decrease from observational data sets obtained by Na lidar, EISCAT VHF radar, and optical instruments at Tromsoe, Norway on 24-25 January 2012. However, all of the previous studies had been carried out based on case studies by ground-based lidar observations. In this study, we have performed, for the first time, statistical analysis using Na density data from 2004 to 2009 obtained with the Optical Spectrograph and InfraRed Imager System (OSIRIS) onboard Odin satellite. In the presentation, we will show relationship between the Na density and geomagnetic activities, and its latitudinal variation. Based on these results, the Na layer response to the energetic particles will be discussed.

  11. Na+ inhibits the epithelial Na+ channel by binding to a site in an extracellular acidic cleft.

    PubMed

    Kashlan, Ossama B; Blobner, Brandon M; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R

    2015-01-01

    The epithelial Na(+) channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na(+), Cl(-), protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na(+) concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na(+) binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na(+). Mutations at selected sites altered the cation inhibitory preference to favor Li(+) or K(+) rather than Na(+). Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na(+). Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  12. Role of the Na(+)-translocating NADH:quinone oxidoreductase in voltage generation and Na(+) extrusion in Vibrio cholerae.

    PubMed

    Vorburger, Thomas; Nedielkov, Ruslan; Brosig, Alexander; Bok, Eva; Schunke, Emina; Steffen, Wojtek; Mayer, Sonja; Götz, Friedrich; Möller, Heiko M; Steuber, Julia

    2016-04-01

    For Vibrio cholerae, the coordinated import and export of Na(+) is crucial for adaptation to habitats with different osmolarities. We investigated the Na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)Na-NMR spectroscopy. The Na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR). In a V. cholerae deletion mutant devoid of the Na(+)-NQR encoding genes (nqrA-F), rates of respiratory Na(+) extrusion were decreased by a factor of four, but the cytoplasmic Na(+) concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (ΔΨ, inside negative) and did not grow under hypoosmotic conditions at pH8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na(+)/H(+) antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na(+) concentrations, the Na(+)-NQR is crucial for generation of a transmembrane voltage to drive the import of H(+) by electrogenic Na(+)/H(+) antiporters. Our study provides the basis to understand the role of the Na(+)-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na(+) pump for respiration. PMID:26721205

  13. Mechanisms contributing to the cardiac inotropic effect of Na pump inhibition and reduction of extracellular Na

    PubMed Central

    1987-01-01

    Reduction of the transsarcolemmal [Na] gradient in rabbit cardiac muscle leads to an increase in the force of contraction. This has frequently been attributed to alteration of Ca movements via the sarcolemmal Na/Ca exchange system. However, the specific mechanisms that mediate the increased force at individual contractions have not been clearly established. In the present study, the [Na] gradient was decreased by reduction of extracellular [Na] or inhibition of the Na pump by either the cardioactive steroid acetylstrophanthidin or by reduction of extracellular [K]. Contractile performance and changes in extracellular Ca (sensed by double-barreled Ca-selective microelectrodes) were studied in order to elucidate the underlying basis for the increase in force. In the presence of agents that inhibit sarcoplasmic reticulum (SR) function (10 mM caffeine, 100-500 nM ryanodine), reduction of the [Na] gradient produced increases in contractile force similar to that observed in the absence of caffeine or ryanodine. It is concluded that an intact, functioning SR is not required for the inotropic effect of [Na] gradient reduction (at least in rabbit ventricle). However, this does not exclude a possible contribution of enhanced SR Ca release in the inotropic response to [Na] gradient reduction in the absence of caffeine or ryanodine. Acetylstrophanthidin (3-5 microM) usually leads to an increase in the magnitude of extracellular Ca depletions associated with individual contractions. However, acetylstrophanthidin can also increase extracellular Ca accumulation during the contraction, especially at potentiated contractions. This extracellular Ca accumulation can be suppressed by ryanodine and it is suggested that this apparent enhancement of Ca efflux is secondary to an enhanced release of Ca from the SR. Under conditions where Ca efflux during contractions is minimized (after a rest interval in the presence of ryanodine), acetylstrophanthidin increased both the rate and the

  14. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  15. The solubility of Cr(OH){sub 3}(am) in concentrated NaOH and NaOH-NaNO{sub 3} solutions

    SciTech Connect

    Felmy, A.R.; Rai, D.; Fulton, R.W.

    1994-08-01

    Chromium is a major component of the Hanford waste tank sludges, and the presence of Cr in the sludges is a significant concern in the disposal of these sludges because Cr can interfere with the formation of waste glasses. One of the current pretreatment strategies for removing constituents that can interfere with glass formation, such as P and Cr, is to wash/dissolve the sludges in basic NaOH solutions. The solubility of Cr(OH){sub 3}(am) was measured in concentrated NaOH ranging in concentration from 0.1M to 6.0M and in NaOH-NaNO{sub 3} solutions with fixed NaOH concentration and variable NaNO{sub 3} concentration at room temperature (22--23 C). Equilibrium between solids and solutions was approached relatively slowly and required approximately 60--70 days before steady-state concentrations were reached. A thermodynamic model, based upon the Pitzer equations, was developed from the solubility data in NaOH, which includes only two aqueous Cr species (Cr(OH){sub 4}{sup {minus}} and NaCr(OH){sub 4}(aq)) and ion-interaction parameters for Na{sup +} with Cr(OH){sub 4}{sup {minus}}. This model was then tested in the mixed NaOH-NaNO{sub 3} solutions and found to be reliable.

  16. 24Mg( p, α)21Na reaction study for spectroscopy of 21Na

    NASA Astrophysics Data System (ADS)

    Cha, S. M.; Chae, K. Y.; Kim, A.; Lee, E. J.; Ahn, S.; Bardayan, D. W.; Chipps, K. A.; Cizewski, J. A.; Howard, M. E.; Manning, B.; O'Malley, P. D.; Ratkiewicz, A.; Strauss, S.; Kozub, R. L.; Matos, M.; Pain, S. D.; Pittman, S. T.; Smith, M. S.; Peters, W. A.

    2015-10-01

    The 24Mg( p, α)21Na reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain the spins and parities of the energy levels in 21Na for the astrophysically important 17F( α, p)20Ne reaction rate calculation. 31-MeV proton beams from the 25-MV tandem accelerator and enriched 24Mg solid targets were used. Recoiling 4He particles from the 24Mg( p, α)21Na reaction were detected by a highly segmented silicon detector array which measured the yields of 4He particles over a range of angles simultaneously. A new level at 6661 ± 5 keV was observed in the present work. The extracted angular distributions for the first four levels of 21Na and the results from distorted wave Born approximation (DWBA) calculations were compared to verify and extract the angular momentum transfer.

  17. Inhibition of Na(+)-independent H+ pump by Na(+)-induced changes in cell Ca2+

    PubMed Central

    1991-01-01

    Apical membrane H+ extrusion in the renal outer medullary collecting duct, inner stripe, is mediated by a Na(+)-independent H+ pump. To examine the regulation of this transporter, cell pH and cell Ca2+ were measured microfluorometrically in in vitro perfused tubules using 2',7'- bis(carboxyethyl)-5(6)-carboxyfluorescein and fura-2, respectively. Apical membrane H+ pump activity, assayed as cell pH recovery from a series of acid loads (NH3/NH+4 prepulse) in the total absence of ambient Na+, initially occurred at a slow rate (0.06 +/- 0.02 pH units/min), which was not sufficient to account for physiologic rates of H+ extrusion. Over 15-20 min after the initial acid load, the rate of Na(+)-independent cell pH recovery increased to 0.63 +/- 0.09 pH units/min, associated with a steady-state cell pH greater than the initial pre-acid load cell pH. This pattern suggested an initial suppression followed by a delayed activation of the apical membrane H+ pump. Replacement of peritubular Na+ with choline or N-methyl-D- glucosamine resulted in an initial spike increase in cell Ca2+ followed by a sustained increase in cell Ca2+. The initial rate of Na(+)- independent cell pH recovery could be increased by elimination of the Na+ removal-induced sustained cell Ca2+ elevation by: (a) performing studies in the presence of 135 mM peritubular Na+ (1 mM peritubular amiloride used to inhibit basolateral membrane Na+/H+ antiport); (b) clamping cell Ca2+ low with dimethyl-BAPTA, an intracellular Ca2+ chelating agent; or (c) removal of extracellular Ca2+. Cell acidification induced a spike increase in cell Ca2+. The late acceleration of Na(+)-independent cell pH recovery was independent of Na+ removal and of the method used to acidify the cell, but was eliminated by prevention of the cell Ca2+ spike and markedly delayed by the microfilament-disrupting agent, cytochalasin B. This study demonstrates that peritubular Na+ removal results in a sustained elevation in cell Ca2+, which inhibits

  18. A Selective Na(+) Aptamer Dissected by Sensitized Tb(3+) Luminescence.

    PubMed

    Zhou, Wenhu; Ding, Jinsong; Liu, Juewen

    2016-08-17

    A previous study of two RNA-cleaving DNAzymes, NaA43 and Ce13d, revealed the possibility of a common Na(+) aptamer motif. Because Na(+) binding to DNA is a fundamental biochemical problem, the interaction between Ce13d and Na(+) was studied in detail by using sensitized Tb(3+) luminescence spectroscopy. Na(+) displaces Tb(3+) from the DNAzyme, and thus quenches the emission from Tb(3+) . The overall requirement for Na(+) binding includes the hairpin and the highly conserved 16-nucleotide loop in the enzyme strand, along with a few unpaired nucleotides in the substrate. Mutation studies indicate good correlation between Na(+) binding and cleavage activity, thus suggesting a critical role of Na(+) binding for the enzyme activity. Ce13d displayed a Kd of ∼20 mm with Na(+) (other monovalent cations: 40-60 mm). The Kd values for other metal ions are mainly due to non-specific competition. With a single nucleotide mutation, the specific Na(+) binding was lost. Another mutant improved Kd to 8 mm with Na(+) . This study has demonstrated a Na(+) aptamer with important biological implications and analytical applications. It has also defined the structural requirements for Na(+) binding and produced an improved mutant. PMID:27238890

  19. Intracellular Na+ regulation of Na+ pump sites in cultured vascular smooth muscle cells

    SciTech Connect

    Allen, J.C.; Navran, S.S.; Seidel, C.L.; Dennison, D.K.; Amann, J.M.; Jemelka, S.K.

    1989-04-01

    Enzymatically dispersed cells from canine saphenous vein and femoral artery were grown in fetal calf serum and studied at day 0 (freshly dispersed) through confluence in primary culture. Intracellular Na levels (Nai), but not intracellular K (Ki), were increased after 24 h in culture and then decreased to a steady state by 4 days. Na+ pump site number (( /sup 3/H) ouabain binding) increased through day 3 and remained elevated. Nai was still elevated at 2 days when the Na+ pump site number began to increase. Total pump turnover (maximum ouabain-inhibited /sup 86/Rb uptake) reflected the increase in Na+ pump site number. These key events precede the observed increases in both protein production and cellular proliferation. If the same cells are maintained in defined medium, without fetal calf serum, Nai, Ki, and the number of (/sup 3/H)ouabain binding sites do not change with time. These data are consistent with the suggestion that the initial mitogenic response of vascular smooth muscle cells to fetal calf serum involves an increased Na+ influx, and a Nai accumulation, caused by low Na+ pump density. The synthesis of new pump sites effects a decrease in the accumulated Nai, which may be related to cell proliferation.

  20. Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

    NASA Technical Reports Server (NTRS)

    Cherng, Jing-Yih; Bennion, Douglas N.

    1987-01-01

    A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

  1. Final-state symmetry of Na 1s core-shell excitons in NaCl and NaF

    SciTech Connect

    Nagle, K.P.; Seidler, G.T.; Shirley, E.L.; Fister, T.T.; Bradley, J.A.; Brown, F.C.

    2009-08-13

    We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence (q dependence) of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s- and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

  2. Final-state symmetry of Na 1s core-shell excitons in NaCl and NaF.

    SciTech Connect

    Nagle, K. P.; Seidler, G. T.; Shirley, E. L.; Fister, T. T.; Bradley, J. A.; Brown, F. C.; Materials Science Division; Univ. of Washington; NIST

    2009-01-01

    We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence (q dependence) of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s- and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

  3. Rescue of Na+ affinity in aspartate 928 mutants of Na+,K+-ATPase by secondary mutation of glutamate 314.

    PubMed

    Holm, Rikke; Einholm, Anja P; Andersen, Jens P; Vilsen, Bente

    2015-04-10

    The Na(+),K(+)-ATPase binds Na(+) at three transport sites denoted I, II, and III, of which site III is Na(+)-specific and suggested to be the first occupied in the cooperative binding process activating phosphorylation from ATP. Here we demonstrate that the asparagine substitution of the aspartate associated with site III found in patients with rapid-onset dystonia parkinsonism or alternating hemiplegia of childhood causes a dramatic reduction of Na(+) affinity in the α1-, α2-, and α3-isoforms of Na(+),K(+)-ATPase, whereas other substitutions of this aspartate are much less disruptive. This is likely due to interference by the amide function of the asparagine side chain with Na(+)-coordinating residues in site III. Remarkably, the Na(+) affinity of site III aspartate to asparagine and alanine mutants is rescued by second-site mutation of a glutamate in the extracellular part of the fourth transmembrane helix, distant to site III. This gain-of-function mutation works without recovery of the lost cooperativity and selectivity of Na(+) binding and does not affect the E1-E2 conformational equilibrium or the maximum phosphorylation rate. Hence, the rescue of Na(+) affinity is likely intrinsic to the Na(+) binding pocket, and the underlying mechanism could be a tightening of Na(+) binding at Na(+) site II, possibly via movement of transmembrane helix four. The second-site mutation also improves Na(+),K(+) pump function in intact cells. Rescue of Na(+) affinity and Na(+) and K(+) transport by second-site mutation is unique in the history of Na(+),K(+)-ATPase and points to new possibilities for treatment of neurological patients carrying Na(+),K(+)-ATPase mutations.

  4. Cardiac Na Channels: Structure to Function.

    PubMed

    DeMarco, K R; Clancy, C E

    2016-01-01

    Heart rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. Opening of the primary cardiac voltage-gated sodium (NaV1.5) channel initiates cellular depolarization and the propagation of an electrical action potential that promotes coordinated contraction of the heart. The regularity of these contractile waves is critically important since it drives the primary function of the heart: to act as a pump that delivers blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. Perturbations to NaV1.5 may alter the structure, and hence the function, of the ion channel and are associated downstream with a wide variety of cardiac conduction pathologies, such as arrhythmias. PMID:27586288

  5. Optically pumped Na/sub 2/ laser

    SciTech Connect

    Kanorskii, S.I.; Kaslin, V.M.; Yakushev, O.F.

    1980-10-01

    A pulsed copper vapor laser emitting the 578.2 nm line was used as the pump source in achieving stimulated emission as a result of the electronic A/sup 1/..sigma../sup +//sub u/ to X/sup 1/..sigma../sup +//sub g/ transitions in the Na/sub 2/ molecule in the spectral range 0.765 to 0.804 ..mu... The average power of all the emission lines was 10 mW when the pulsed pump power was 150 W and the efficiency of conversion of the optical pump energy was about 3%. The pulse repetition frequency was 3.3 kHz. Violet diffuse radiation of the Na/sub 2/ molecules, generated by pumping with the copper vapor laser, was observed. The superradiance regime was found for some of the lines.

  6. Igneous origin for the NA in the cloud of Io

    NASA Astrophysics Data System (ADS)

    Johnson, M. L.; Burnett, D. S.

    1990-06-01

    Mixtures of sulfur and Na-bearing silicates were heated in evacuated silica glass capsules to temperatures between 600 C and 950 C. At or above 850 C, Na-silicate glass reacts with elemental S to form a (Na, K) sulfide. Mobilization of this phase may account for the presence of Na and K on the surface of Io, and hence in the material sputtered onto the Jovian magnetosphere.

  7. Sources of Na for the Io atmosphere

    NASA Technical Reports Server (NTRS)

    Burnett, D. S.; Ellis, Susan B.; Rice, A.; Epstein, S.

    1993-01-01

    The physics and geology of Io have been extensively studied, but there has been little discussion of the chemistry. Relatively little is known about Io chemistry, but there are constraints. Further, it will be a long time before improvements will result from direct observation, given the severe difficulties with the Galileo mission. Via laboratory simulation experiments, plausible thermochemical and photochemical processes which determine the nature and amounts of surface constituents of Io are explored. The well-known density of Io shows that the planet overall is rocky. Because the orbit of Io is well within the magnetosphere of Jupiter and because Io only has a thin, transient SO2 atmosphere, the surface is continually sputtered with magnetospheric ions. Complex processes ionize and accelerate the Io surface atoms to keV and MeV energies. Remarkably, only S, O, and Na ions were found by Voyager. Sputtering also produces an atomic cloud of Na and S (O not observable) with a trace of K. Both gaseous and solid SO2 are known from spectroscopic studies. A trace of H2S and possibly CO2 are present. Geologic features are interpreted in terms of elemental S, but there is no direct evidence for this constituent. We thus have a rocky planet which does not have rocks on the surface. Our general goal is to understand the cycling of Na, S, and O through the crust and atmosphere on present-day Io and to understand how Io evolved to this state. A specific objective was to determine the phases on the surface which are the source of the Na in the atmosphere of Io.

  8. Hybrid thermoelastic properties of NaCl

    NASA Astrophysics Data System (ADS)

    Wentzcovitch, R. M.; Marcondes, M. L.; Shukla, G.

    2015-12-01

    Despite the importance of thermoelastic properties of minerals in geophysics, their measurements at high pressures and temperatures are limited. Thus, ab initio calculations are an essential tool for predicting these properties at extreme conditions. Owing to the approximate description of the exchange-correlation energy and to approximations used in calculations of vibrational effects, these methods produce systematic deviations. Hybrid schemes combining experimental data and theoretical results have emerged as a way to reconcile available information and offer more reliable predictions at experimentally inaccessible thermodynamics conditions. Here we introduce a hybrid scheme to reconcile calculated and measured elastic coefficients and apply it to rock-salt-type NaCl, a challenging material to describe by ab initio and an important mineral in the context of oil/gas exploration. The approach is predictive within the temperature range of validity of the quasiharmonic approximation and results are used to generate velocities of NaCl at desirable geological conditions. [1] Marcondes, M. L. & Wentzcovitch, R.M. (2015). Hybrid ab-initio/experimental thermal equations of state: application to the NaCl pressure scale, J. Appl. Phys. 117:215902.

  9. Na+ transport in Acetabularia bypasses conductance of plasmalemma.

    PubMed

    Amtmann, A; Gradmann, D

    1994-04-01

    Na(+)-selective microelectrodes with the sensor ETH 227 have been used to measure the cytoplasmic Na+ concentration, [Na+]c, in Acetabularia. In the steady-state, [Na+]c is about 60 mM (external 460 mM). Steps in external Na+ concentration, [Na+]o, cause biexponential relaxations of [Na+]c which have formally been described by a serial three-compartment model (outside<==>compartment 1<==>compartment 2). From the initial slopes (some mMsec-1) net uptake and release of about 3 mumolm-2sec-1 Na+ are determined. Surprisingly, but consistent with previous tracer flux measurements (Mummert, H., Gradmann, D. 1991. J. Membrane Biol, 124:255-263), these Na+ fluxes are not accompanied by corresponding changes of the transplasmalemma voltage. [Na+]c is neither affected by the membrane voltage, nor by electrochemical gradients of H+ or Cl- across the plasmalemma, nor by cytoplasmic ATP. The results suggest a powerful vesicular transport system for ions which bypasses the conductance of the plasmalemma. In addition, transient increases of [Na+]c have been observed to take place facultatively during action potentials. The exponential distribution of the amplitudes of these transients (many small and few large peaks) points to local events in the more ore less close vicinity of the Na+ recording electrode. These events are suggested to consist of disruption of endoplasmic vesicles due to a loss of pressure in the cytoplasm.

  10. Genome Sequences of Cupriavidus metallidurans Strains NA1, NA4, and NE12, Isolated from Space Equipment.

    PubMed

    Monsieurs, Pieter; Mijnendonckx, Kristel; Provoost, Ann; Venkateswaran, Kasthuri; Ott, C Mark; Leys, Natalie; Van Houdt, Rob

    2014-01-01

    Cupriavidus metallidurans NA1, NA4, and NE12 were isolated from space and spacecraft-associated environments. Here, we report their draft genome sequences with the aim of gaining insight into their potential to adapt to these environments.

  11. Effects of altering the ATP/ADP ratio on pump-mediated Na/K and Na/Na exchanges in resealed human red blood cell ghosts

    PubMed Central

    1986-01-01

    Resealed human red blood cell ghosts were prepared to contain a range of ADP concentrations at fixed ATP concentrations and vice versa. ATP/ADP ratios ranging from approximately 0.2 to 50 were set and maintained (for up to 45 min) in this system. ATP and ADP concentrations were controlled by the addition of either a phosphoarginine- or phosphocreatine-based regenerating system. Ouabain- sensitive unidirectional Na efflux was determined in the presence and absence of 15 mM external K as a function of the nucleotide composition. Na/K exchange was found to increase to saturation with ATP (K 1/2 approximately equal to 250 microM), whereas Na/Na exchange (measured in K-free solutions) was a saturating function of ADP (K 1/2 approximately equal to 350 microM). The elevation of ATP from approximately 100 to 1,800 microM did not appreciably affect Na/Na exchange. In the presence of external Na and a saturating concentration of external K, increasing the ADP concentration at constant ATP was found to decrease ouabain-sensitive Na/K exchange. The decreased Na/K exchange that still remained when the ADP/ATP ratio was high was stimulated by removal of external Na. Assuming that under normal substrate conditions the reaction cycle of the Na/K pump is rate- limited by the conformational change associated with the release of occluded K [E2 X (K) X ATP----E1 X ATP + K], increasing ADP inhibits the rate of these transformations by competition with ATP for the E2(K) form. A less likely alternative is that inhibition is due to competition with ATP at the high-affinity site (E1). The acceleration of the Na/K pump that occurs upon removing external Na at high levels of ADP evidently results from a shift in the forward direction of the transformation of the intermediates involved with the release of occluded Na from E1P X (Na). Thus, the nucleotide composition and the Na gradient can modulate the rate at which the Na/K pump operates. PMID:3950576

  12. Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Allen, F. G.; Yu, J. G.

    1976-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

  13. pNaKtide inhibits Na/K-ATPase reactive oxygen species amplification and attenuates adipogenesis

    PubMed Central

    Sodhi, Komal; Maxwell, Kyle; Yan, Yanling; Liu, Jiang; Chaudhry, Muhammad A.; Getty, Morghan; Xie, Zijian; Abraham, Nader G.; Shapiro, Joseph I.

    2015-01-01

    Obesity has become a worldwide epidemic and is a major risk factor for metabolic syndrome. Oxidative stress is known to play a role in the generation and maintenance of an obesity phenotype in both isolated adipocytes and intact animals. Because we had identified that the Na/K-ATPase can amplify oxidant signaling, we speculated that a peptide designed to inhibit this pathway, pNaKtide, might ameliorate an obesity phenotype. To test this hypothesis, we first performed studies in isolated murine preadipocytes (3T3L1 cells) and found that pNaKtide attenuated oxidant stress and lipid accumulation in a dose-dependent manner. Complementary experiments in C57Bl6 mice fed a high-fat diet corroborated our in vitro observations. Administration of pNaKtide in these mice reduced body weight gain, restored systemic redox and inflammatory milieu, and, crucially, improved insulin sensitivity. Thus, we propose that inhibition of Na/K-ATPase amplification of oxidative stress may ultimately be a novel way to combat obesity, insulin resistance, and metabolic syndrome. PMID:26601314

  14. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.

    PubMed

    Dracatos, Peter M; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A; Plummer, Kim M

    2016-09-03

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2.

  15. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi

    PubMed Central

    Dracatos, Peter M.; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A.; Plummer, Kim M.

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  16. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.

    PubMed

    Dracatos, Peter M; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A; Plummer, Kim M

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  17. Na+ channel function, regulation, structure, trafficking and sequestration

    PubMed Central

    Chen-Izu, Ye; Shaw, Robin M; Pitt, Geoffrey S; Yarov-Yarovoy, Vladimir; Sack, Jon T; Abriel, Hugues; Aldrich, Richard W; Belardinelli, Luiz; Cannell, Mark B; Catterall, William A; Chazin, Walter J; Chiamvimonvat, Nipavan; Deschenes, Isabelle; Grandi, Eleonora; Hund, Thomas J; Izu, Leighton T; Maier, Lars S; Maltsev, Victor A; Marionneau, Celine; Mohler, Peter J; Rajamani, Sridharan; Rasmusson, Randall L; Sobie, Eric A; Clancy, Colleen E; Bers, Donald M

    2015-01-01

    This paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na+ channel function and regulation, Na+ channel structure and function, and Na+ channel trafficking, sequestration and complexing. PMID:25772290

  18. Determination of Na(2)O from sodium aluminate NaAlO(2).

    PubMed

    Näykki, T; Raimo, A; Paavo, P; Antero, K; Päivi, N

    2000-07-31

    The aim of the work was to find a suitable method and conditions for determining Na(2)O wt.% from NaAlO(2). Problems were encountered while titrating NaAlO(2) with hydrochloric acid. The problematic area was the pH range 4-10 where aluminum precipitates as hydroxides. The different species of the aluminate solution were determined using potentiometric and complexometric titrations. The equivalent point of the potentiometric titration was detected using Gran's plotting method. Precipitation of aluminum hydroxides did not interfere with titrations, because in potentiometric titrations the pH value was over 10 and in complexometric titrations the pH was 4. The results were accurate and determinations were easy to carry out. Sodium was also determined by DCP-AES.

  19. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    SciTech Connect

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-15

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO{sub 2} and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO{sub 2}/Al{sub 2}O{sub 3}, H{sub 2}O/Na{sub 2}O and Na{sub 2}O/SiO{sub 2} molar ratios of precursors in the two-step process. The surface area and NH{sub 4}{sup +}-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m{sup 2}/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m{sup 2}/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of {approx}3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  20. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions.

  1. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions. PMID:27112871

  2. Respiratory-driven Na+ electrical potential in the bacterium Vitreoscilla.

    PubMed

    Efiok, B J; Webster, D A

    1990-05-15

    Vitreoscilla is a Gram-negative bacterium with unique respiratory physiology in which Na+ was implicated as a coupling cation for the generation of a transmembrane electrical gradient (delta psi). Thus, cells respiring in the presence of 110 mM Na+ generated a delta psi of -142 mV compared to only -42 and -56 mV for Li+ and choline, respectively, and even the -42 and -56 mV were insensitive to the protonophore 3,5-di-tert-butyl-4-hydroxybenzaldehyde (DTHB). The kinetics of delta psi formation and collapse correlated well with the kinetics of Na+ fluxes but not with those of H+ fluxes. Cyanide inhibited respiration, Na+ extrusion, and delta psi formation 81% or more, indicating that delta psi formation and Na+ extrusion were coupled to respiration. Experiments were performed to distinguish among three possible transport systems for this coupling: (1) a Na(+)-transporting ATPase; (2) an electrogenic Na+/H+ antiport system; (3) a primary Na+ pump directly driven by the free energy of electron transport. DCCD and arsenate decreased cellular ATP up to 86% but had no effect on delta psi, evidence against a Na(+)-transporting ATPase. Low concentrations of DTHB had no effect on delta psi; high concentrations transiently collapsed delta psi, but led to a stimulation of Na+ extrusion, the opposite of that expected for a Na+/H+ antiport system. Potassium ion, which collapses delta psi, also stimulated Na+ extrusion. The experimental evidence is against Na+ extrusion by mechanisms 1 and 2 and supports the existence of a respiratory-driven primary Na+ pump for generating delta psi in Vitreoscilla. PMID:2372555

  3. Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

    NASA Astrophysics Data System (ADS)

    Zhou, Xu; Liu, Cong-Zhan; Zhao, Jian-Ling; Zhang, Fei; Zhang, Yi-Fei; Li, Zheng-Wei; Zhang, Shuo; Li, Xu-Fang; Lu, Xue-Feng; Xu, Zhen-Ling; Lu, Fang-Jun

    2014-02-01

    We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically.

  4. Direct Reactions with MoNA-LISA

    NASA Astrophysics Data System (ADS)

    Kuchera, Anthony

    2016-03-01

    Nuclear reactions can be used to probe the structure of nuclei. Direct reactions, which take place on short time scales, are well-suited for experiments with beams of short-lived nuclei. One such reaction is nucleon knockout where a proton or neutron is removed from the incoming beam from the interaction with a target. Single nucleon knockout reactions have been used to study the single-particle nature of nuclear wave functions. A recent experiment at the National Superconducting Cyclotron Laboratory was performed to measure cross sections from single nucleon knockout reactions for several p-shell nuclei. Detection of the residual nucleus in coincidence with any gamma rays emitted from the target allowed cross sections to ground and excited states to be measured. Together with input from reaction theory, ab initio structure theories can be tested. Simultaneously the accuracy of knockout reaction models can be validated by detecting the knocked out neutron with the Modular Neutron Array and Large multi-Institutional Scintillator Array (MoNA-LISA). Preliminary results from this experiment will be shown. Knockout reactions can also be used to populate nuclei which are neutron unbound, thus emit neutrons nearly instantaneously. The structure of these nuclei, therefore, cannot be probed with gamma ray spectroscopy. However, with large neutron detectors like MoNA-LISA the properties of these short-lived nuclei are able to be measured. Recent results using MoNA-LISA to study the structure of neutron-rich nuclei will be presented. The author would like to acknowledge support from the NNSA and NSF.

  5. The NA62 spectrometer acquisition system

    NASA Astrophysics Data System (ADS)

    Azorskiy, N.; Ceccucci, A.; Bendotti, J.; Danielsson, H.; Degrange, J.; Dixon, N.; Elsha, V.; Enik, T.; Glonti, L.; Gusakov, Y.; Kakurin, S.; Kekelidze, V.; Kislov, E.; Kolesnikov, A.; Koval, M.; Lichard, P.; Madigozhin, D.; Morant, J.; Movchan, S.; Perez Gomez, F.; Palladino, V.; Polenkevich, I.; Potrebenikov, Y.; Ruggiero, G.; Samsonov, V.; Shkarovskiy, S.; Sotnikov, A.

    2016-02-01

    The NA62 low mass spectrometer consists of 7000 straw tubes operating in vacuum. The front-end electronics is directly mounted on the detector and connected by a flexible PCB. The front-end board provides the amplification, shaping, discrimination and time measurements of the analogue signals from 16 channels. After digitisation the data is sent to a VME 9U read-out board. The data, once matched with the trigger, is sent to the next step and used by the trigger level 1 algorithm. The front-end and read-out systems of the detector will be presented along with the first results of the detector performances.

  6. [Effects of NaCl stress on the seedling growth and K(+)- and Na(+) -allocation of four leguminous tree species].

    PubMed

    Mo, Hai-Bo; Yin, Yun-Long; Lu, Zhi-Guo; Wei, Xiu-Jun; Xu, Jian-Hua

    2011-05-01

    Taking the pot-cultured seedlings of four leguminous tree species (Albizia julibrissin, Robinia pseudoacacia, Sophora japonica, and Gleditsia sinensis) as test materials, this paper studied their growth indices, critical salt concentration (C50), and K+ and Na+ allocation under different levels of NaCl stress, aimed to understand the difference of test tree species in salt tolerance. NaCl stress inhibited the seedling growth of the tree species. Under NaCl stress, the dry matter accumulation decreased, while the root/shoot ratio increased, especially for A. julibrissin and G. sinensis. Quadratic regression analysis showed that the C50 of A. julibrissin, R. pseudoacacia, S. japonica, and G. sinensis was 3.0 per thousand, 5.0 per thousand, 4.5 per thousand, and 3.9 per thousand, respectively, i.e., the salt tolerance of the four tree species was in the order of R. pseudoacacia > S. japonica > G. sinensis > A. julibrissin. In the root, stem, and leaf of the four tree species seedlings, the Na+ content increased with the increase of NaCl stress, while the K+ content (except in the root of A. julibrissin) decreased after an initial increase, resulting in a larger difference in the K+/Na+ ratio in the organs. Under the same NaCl stress, the allocation of Na+ in different organs of the four tree species seedlings decreased in the order of root>stem>leaf, while that of K+ differed with tree species and NaCl stress, and leaf was the main storage organ for K+. The K+/Na+ ratio in different organs decreased in the sequence of leaf>stem>root. R. pseudoacacia under NaCl stress accumulated more K+ and less Na+ in stem and leaf, and had higher K+/Na+ ratio in all organs and higher dry mass, being assessed to be more salt-tolerant. In contrast, A. julibrissin under high NaCl stress accumulated more Na+ in stem and leaf, and had a lower K+/Na+ ratio in all organs and lower dry mass, being evaluated to be lesser salt-tolerant. The K+ accumulation in seedling stem and leaf and the Na

  7. Asymmetry of Na-K-Cl cotransport in human erythrocytes.

    PubMed

    Kracke, G R; Anatra, M A; Dunham, P B

    1988-02-01

    The Na-K-Cl cotransport system in human erythrocytes was studied by measuring net influxes and effluxes of Na and K. The influx of K was shown to be stimulated by Na and the influx of Na was stimulated by K, satisfying the fundamental criterion of cotransport. In addition, these mutually stimulating cation influxes had a stoichiometry of 1:1 and were entirely inhibited by furosemide; these results are also consistent with cotransport. Furthermore, the mutually stimulating influxes were entirely dependent on Cl, since they were abolished when nitrate was substituted for Cl. In contrast, cotransport, defined by mutual dependence of fluxes, was not detected in the outward direction over a range of cellular Na and K concentrations from 0 to 50 mmol/l cells. The cotransport pathway did, however, appear to mediate a Na-stimulated K efflux (but no K-stimulated Na efflux), and furosemide-inhibitable effluxes of both Na and K. Nitrate (but not sulfate) appeared to substitute for chloride in promoting Na-stimulated K efflux. Thus the Na-K-Cl cotransport system in human red cells is intrinsically asymmetric, and mediates coupled cation fluxes readily only in the inward direction. PMID:3348364

  8. Hydrogen sulfide induced disruption of Na+ homeostasis in the cortex.

    PubMed

    Chao, Dongman; He, Xiaozhou; Yang, Yilin; Balboni, Gianfranco; Salvadori, Severo; Kim, Dong H; Xia, Ying

    2012-07-01

    Maintenance of ionic balance is essential for neuronal functioning. Hydrogen sulfide (H(2)S), a known toxic environmental gaseous pollutant, has been recently recognized as a gasotransmitter involved in numerous biological processes and is believed to play an important role in the neural activities under both physiological and pathological conditions. However, it is unclear if it plays any role in maintenance of ionic homeostasis in the brain under physiological/pathophysiological conditions. Here, we report by directly measuring Na(+) activity using Na(+) selective electrodes in mouse cortical slices that H(2)S donor sodium hydrosulfide (NaHS) increased Na(+) influx in a concentration-dependent manner. This effect could be partially blocked by either Na(+) channel blocker or N-methyl-D-aspartate receptor (NMDAR) blocker alone or almost completely abolished by coapplication of both blockers but not by non-NMDAR blocker. These data suggest that increased H(2)S in pathophysiological conditions, e.g., hypoxia/ischemia, potentially causes a disruption of ionic homeostasis by massive Na(+) influx through Na(+) channels and NMDARs, thus injuring neural functions. Activation of delta-opioid receptors (DOR), which reduces Na(+) currents/influx in normoxia, had no effect on H(2)S-induced Na(+) influx, suggesting that H(2)S-induced disruption of Na(+) homeostasis is resistant to DOR regulation and may play a major role in neuronal injury in pathophysiological conditions, e.g., hypoxia/ischemia.

  9. Minimizing Load Effects on NA4 Gear Vibration Diagnostic Parameter

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Zakrajsek, James J.

    2001-01-01

    NA4 is a vibration diagnostic parameter, developed by researchers at NASA Glenn Research Center, for health monitoring of gears in helicopter transmissions. The NA4 reacts to the onset of gear pitting damage and continues to react to the damage as it spreads. This research also indicates NA4 reacts similarly to load variations. The sensitivity of NA4 to load changes will substantially affect its performance on a helicopter gearbox that experiences continuously changing load throughout its flight regimes. The parameter NA4 has been used to monitor gear fatigue tests at constant load. At constant load, NA4 effectively detects the onset of pitting damage and tracks damage severity. Previous research also shows that NA4 reacts to changes in load applied to the gears in the same way it reacts to the onset of pitting damage. The method used to calculate NA4 was modified to minimize these load effects. The modified NA4 parameter was applied to four sets of experimental data. Results indicate the modified NA4 is no longer sensitive to load changes, but remains sensitive to pitting damage.

  10. Naïve point estimation.

    PubMed

    Lindskog, Marcus; Winman, Anders; Juslin, Peter

    2013-05-01

    The capacity of short-term memory is a key constraint when people make online judgments requiring them to rely on samples retrieved from memory (e.g., Dougherty & Hunter, 2003). In this article, the authors compare 2 accounts of how people use knowledge of statistical distributions to make point estimates: either by retrieving precomputed large-sample representations or by retrieving small samples of similar observations post hoc at the time of judgment, as constrained by short-term memory capacity (the naïve sampling model: Juslin, Winman, & Hansson, 2007). Results from four experiments support the predictions by the naïve sampling model, including that participants sometimes guess values that they, when probed, demonstrably know have the lowest probability of occurring. Experiment 1 also demonstrated the operations of an unpredicted recognition-based inference. Computational modeling also incorporating this process demonstrated that the data from all 4 experiments were better predicted by assuming a post hoc sampling process constrained by short-term memory capacity than by assuming abstraction of large-sample representations of the distribution. PMID:22905935

  11. Apical Na+ permeability of frog skin during serosal Cl- replacement.

    PubMed

    Leibowich, S; DeLong, J; Civan, M M

    1988-05-01

    Gluconate substitution for serosal Cl- reduces the transepithelial short-circuit current (Isc) and depolarizes short-circuited frog skins. These effects could result either from inhibition of basolateral K+ conductance, or from two actions to inhibit both apical Na+ permeability (PapNa) and basolateral pump activity. We have addressed this question by studying whole-and split-thickness frog skins. Intracellular Na+ concentration (CcNa) and PapNa have been monitored by measuring the current-voltage relationship for apical Na+ entry. This analysis was conducted by applying trains of voltage pulses, with pulse durations of 16 to 32 msec. Estimates of PapNa and CcNa were not detectably dependent on pulse duration over the range 16 to 80 msec. Serosal Cl- replacement uniformly depolarized short-circuited tissues. The depolarization was associated with inhibition of Isc across each split skin, but only occasionally across the whole-thickness preparations. This difference may reflect the better ionic exchange between the bulk medium and the extracellular fluid in contact with the basolateral membranes, following removal of the underlying dermis in the split-skin preparations. PapNa was either unchanged or increased, and CcNa either unchanged or reduced after the anionic replacement. These data are incompatible with the concept that serosal Cl- replacement inhibits PapNa and Na,K-pump activity. Gluconate substitution likely reduces cell volume, triggering inhibition of the basolateral K+ channels, consistent with the data and conclusions of S.A. Lewis, A.G. Butt, M.J. Bowler, J.P. Leader and A.D.C. Macknight (J. Membrane Biol. 83:119-137, 1985) for toad bladder. The resulting depolarization reduces the electrical force favoring apical Na+ entry. The volume-conductance coupling serves to conserve volume by reducing K+ solute loss. Its molecular basis remains to be identified.

  12. Interaction of the Na+-K+ pump and Na+-Ca2+ exchange via [Na+]i in a restricted space of guinea-pig ventricular cells.

    PubMed

    Fujioka, Y; Matsuoka, S; Ban, T; Noma, A

    1998-06-01

    1. The whole-cell Na+-K+ pump current (INa-K) and Na+-Ca2+ exchange current (INa-Ca) were recorded in guinea-pig ventricular myocytes to study the interaction between the two Na+ transport mechanisms. 2. INa-K was isolated as an external K+-induced current, and INa-Ca as an external Ca2+- induced or Ni2+-sensitive current. The experimental protocol used for one ion carrier did not affect the other. 3. The amplitude of INa-K decreased to 54 +/- 17 % of the initial peak during continuous application of K+ with 20 mM Na+ in the pipette. The outward INa-Ca, which was intermittently activated by brief applications of Ca2+, decreased during activation of INa-K, and recovered after cessation of INa-K activation. These findings revealed a dynamic interaction between INa-K and INa-Ca via a depletion of Na+ under the sarcolemma. 4. To estimate changes in Na+ concentration ([Na+]i) under the sarcolemma, the reversal potential (Vrev) of INa-Ca was measured. Unexpectedly, Vrev hardly changed during activation of INa-K. However, when INa-Ca was blocked by Ni2+ at the same time that INa-K was activated, Vrev changed markedly, maximally by +100 mV, immediately after the removal of Ni2+ and K+. 5. Subsarcolemmal [Na+]i was calculated from the Vrev of INa-Ca on the assumption that the subsarcolemmal Ca2+ concentration ([Ca2+]i) was fixed with EGTA, and mean [Na+]i was calculated from both the time integral of INa-K and the cell volume. The subsarcolemmal [Na+]i was about seven times greater than the mean [Na+]i. 6. The interaction between the Na+-K+ pump and Na+-Ca2+ exchange was well simulated by a diffusion model, in which Na+ diffusion was restricted to one-seventh (14 %) of the total cell volume.

  13. Regulation of persistent Na current by interactions between β subunits of voltage-gated Na channels

    PubMed Central

    Aman, Teresa K.; Grieco-Calub, Tina M.; Chen, Chunling; Rusconi, Raffaella; Slat, Emily A.; Isom, Lori L.; Raman, Indira M.

    2009-01-01

    The β subunits of voltage-gated Na channels (Scnxb) regulate the gating of pore-forming α subunits, as well as their trafficking and localization. In heterologous expression systems, β1, β2, and β3 subunits influence inactivation and persistent current in different ways. To test how the β4 protein regulates Na channel gating, we transfected β4 into HEK cells stably expressing NaV1.1. Unlike a free peptide with a sequence from the β4 cytoplasmic domain, the full-length β4 protein did not block open channels. Instead, β4 expression favored open states by shifting activation curves negative, decreasing the slope of the inactivation curve, and increasing the percentage of non-inactivating current. Consequently, persistent current tripled in amplitude. Expression of β1 or chimeric subunits including the β1 extracellular domain, however, favored inactivation. Co-expressing NaV1.1 and β4 with β1 produced tiny persistent currents, indicating that β1 overcomes the effects of β4 in heterotrimeric channels. In contrast, β1C121W, which contains an extracellular epilepsy-associated mutation, did not counteract the destabilization of inactivation by β4, and also required unusually large depolarizations for channel opening. In cultured hippocampal neurons transfected with β4, persistent current was slightly but significantly increased. Moreover, in β4-expressing neurons from Scn1b and Scn1b/Scn2b null mice, entry into inactivated states was slowed. These data suggest that β1 and β4 have antagonistic roles, the former favoring inactivation and the latter favoring activation. Because increased Na channel availability may facilitate action potential firing, these results suggest a mechanism for seizure susceptibility of both mice and humans with disrupted β1 subunits. PMID:19228957

  14. [Na] and [K] dependence of the Na/K pump current-voltage relationship in guinea pig ventricular myocytes

    PubMed Central

    1989-01-01

    Na/K pump current was determined between -140 and +60 mV as steady- state, strophanthidin-sensitive, whole-cell current in guinea pig ventricular myocytes, voltage-clamped and internally dialyzed via wide- tipped pipettes. Solutions were designed to minimize all other components of membrane current. A device for exchanging the solution inside the pipette permitted investigation of Na/K pump current-voltage (I-V) relationships at several levels of pipette [Na] [( Na]pip) in a single cell; the effects of changes in external [Na] [( Na]o) or external [K] [( K]o) were also studied. At 50 mM [Na]pip, 5.4 mM [K]o, and approximately 150 mM [Na]o, Na/K pump current was steeply voltage dependent at negative potentials but was approximately constant at positive potentials. Under those conditions, reduction of [Na]o enhanced pump current at negative potentials but had little effect at positive potentials: at zero [Na]o, pump current was only weakly voltage dependent. At 5.4 mM [K]o and approximately 150 mM [Na]o, reduction of [Na]pip from 50 mM scaled down the sigmoid pump I-V relationship and shifted it slightly to the right (toward more positive potentials). Pump current at 0 mV was activated by [Na]pip according to the Hill equation with best-fit K0.5 approximately equal to 11 mM and Hill coefficient nH approximately equal to 1.4. At zero [Na]o, reduction of [Na]pip seemed to simply scale down the relatively flat pump I-V relationship: Hill fit parameters for pump activation by [Na]pip at 0 mV were K0.5 approximately equal to 10 mM, nH approximately equal to 1.4. At 50 mM [Na]pip and high [Na]o, reduction of [K]o from 5.4 mM scaled down the sigmoid I-V relationship and shifted it slightly to the right: at 0 mV, K0.5 approximately equal to 1.5 mM and nH approximately equal to 1.0. At zero [Na]o, lowering [K]o simply scaled down the flat pump I-V relationships yielding, at 0 mV, K0.5 approximately equal to 0.2 mM, nH approximately equal to 1.1. The voltage

  15. Coordinated regulation of cardiac Na(+)/Ca (2+) exchanger and Na (+)-K (+)-ATPase by phospholemman (FXYD1).

    PubMed

    Cheung, Joseph Y; Zhang, Xue-Qian; Song, Jianliang; Gao, Erhe; Chan, Tung O; Rabinowitz, Joseph E; Koch, Walter J; Feldman, Arthur M; Wang, JuFang

    2013-01-01

    Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the α-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure.

  16. Quantitative 23Na magnetic resonance imaging of model foods.

    PubMed

    Veliyulin, Emil; Egelandsdal, Bjørg; Marica, Florin; Balcom, Bruce J

    2009-05-27

    Partial (23)Na MRI invisibility in muscle foods is often referred to as an inherent drawback of the MRI technique, impairing quantitative sodium analysis. Several model samples were designed to simulate muscle foods with a broad variation in protein, fat, moisture, and salt content. (23)Na spin-echo MRI and a recently developed (23)Na SPRITE MRI approach were compared for quantitative sodium imaging, demonstrating the possibility of accurate quantitative (23)Na MRI by the latter method. Good correlations with chemically determined standards were also obtained from bulk (23)Na free induction decay (FID) and CPMG relaxation experiments on the same sample set, indicating their potential use for rapid bulk NaCl measurements. Thus, the sodium MRI invisibility is a methodological problem that can easily be circumvented by using the SPRITE MRI technique. PMID:21314196

  17. Pyrophosphate-fueled Na+ and H+ transport in prokaryotes.

    PubMed

    Baykov, Alexander A; Malinen, Anssi M; Luoto, Heidi H; Lahti, Reijo

    2013-06-01

    In its early history, life appeared to depend on pyrophosphate rather than ATP as the source of energy. Ancient membrane pyrophosphatases that couple pyrophosphate hydrolysis to active H(+) transport across biological membranes (H(+)-pyrophosphatases) have long been known in prokaryotes, plants, and protists. Recent studies have identified two evolutionarily related and widespread prokaryotic relics that can pump Na(+) (Na(+)-pyrophosphatase) or both Na(+) and H(+) (Na(+),H(+)-pyrophosphatase). Both these transporters require Na(+) for pyrophosphate hydrolysis and are further activated by K(+). The determination of the three-dimensional structures of H(+)- and Na(+)-pyrophosphatases has been another recent breakthrough in the studies of these cation pumps. Structural and functional studies have highlighted the major determinants of the cation specificities of membrane pyrophosphatases and their potential use in constructing transgenic stress-resistant organisms.

  18. Simulation of Na D emission near Europa during eclipse

    USGS Publications Warehouse

    Cassidy, T.A.; Johnson, R.E.; Geissler, P.E.; Leblanc, F.

    2008-01-01

    The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain. Copyright 2008 by the American Geophysical Union.

  19. Magnesium correction to the NaKCa chemical geothermometer

    USGS Publications Warehouse

    Fournier, R.O.; Potter, R.W., II

    1979-01-01

    Equations and graphs have been devised to correct for the adverse effects of magnesium upon the Na-K-Ca chemical geothermometer. Either the equations or graphs can be used to determine appropriate temperature corrections for given waters with calculated NaKCa temperatures > 70??C and R 50 are probably derived from relatively cool aquifers with temperatures approximately equal to the measured spring temperature, irrespective of much higher calculated Na-K-Ca temperatures. ?? 1979.

  20. Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3

    NASA Astrophysics Data System (ADS)

    Yahia, H. Ben; Essehli, R.; Avdeev, M.; Park, J.-B.; Sun, Y.-K.; Al-Maadeed, M. A.; Belharouak, I.

    2016-06-01

    The new compounds NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 crystallize with a stuffed α-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)3 the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 delivered specific capacities of 352, 385, and 368 mA h g-1, respectively, which attests to the electrochemical activity of sodium in these compounds.

  1. Advanced Intermediate-Temperature Na-S Battery

    SciTech Connect

    Lu, Xiaochuan; Kirby, Brent W.; Xu, Wu; Li, Guosheng; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2012-11-12

    In this study, we reported an intermediate-temperature (~150°C) sodium-sulfur (Na-S) battery. With a reduced operating temperature, this novel battery can potentially reduce the cost and safety issues associated with the conventional high-temperature (300~350°C) Na-S battery. A dense β"-Al2O3 solid membrane and tetraglyme were utilized as the electrolyte separator and catholyte solvent in this battery. Solubility tests indicated that cathode mixture of Na2S4 and S exhibited extremely high solubility in tetraglyme (e.g., > 4.1 M for Na2S4 + 4 S). CV scans of Na2S4 in tetraglyme revealed two pairs of redox couples with peaks at around 2.22 and 1.75 V, corresponding to the redox reactions of polysulfide species. The discharge/charge profiles of the Na-S battery showed a slope region and a plateau, indicating multiple steps and cell reactions. In-situ Raman measurements during battery operation suggested that polysulfide species were formed in the sequence of Na2S5 + S → Na2S5 + Na2S4Na2S4 + Na2S2 during discharge and in a reverse order during charge. This battery showed dramatic improvement in rate capacity and cycling stability over room-temperature Na-S batteries, which makes it attractive for renewable energy integration and other grid related applications.

  2. Effects of Cl adatom on Na-Decorated graphene

    NASA Astrophysics Data System (ADS)

    Song, Xinxiang; Sun, Yu; Dong, Meifeng; Li, Chun; Wang, Jiesheng; Mimura, Hidenori; Yuan, Guang

    2015-06-01

    The effects of the Cl adatom on Na-decorated graphene are studied using first principles density functional theory under the generalized gradient approximation to calculate the adsorption energy, geometric structure, charge density difference, and density of states. When Na and Cl adatoms are simultaneously absorbed on opposite sides of graphene, the adsorption energy of Na increases by about 1 eV and the adsorption system becomes more stable because graphene can effectively transfer the 3s valence of the Na adatom to the Cl adatom.

  3. Transcriptional regulators of Na,K-ATPase subunits

    PubMed Central

    Li, Zhiqin; Langhans, Sigrid A.

    2015-01-01

    The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease. PMID:26579519

  4. Kaolin-based geopolymers with various NaOH concentrations

    NASA Astrophysics Data System (ADS)

    Heah, C. Y.; Kamarudin, H.; Mustafa Al Bakri, A. M.; Bnhussain, M.; Luqman, M.; Khairul Nizar, I.; Ruzaidi, C. M.; Liew, Y. M.

    2013-03-01

    Kaolin geopolymers were produced by the alkali-activation of kaolin with an activator solution (a mixture of NaOH and sodium silicate solutions). The NaOH solution was prepared at a concentration of 6-14 mol/L and was mixed with the sodium silicate solution at a Na2SiO3/NaOH mass ratio of 0.24 to prepare an activator solution. The kaolin-to-activator solution mass ratio used was 0.80. This paper aimed to analyze the effect of NaOH concentration on the compressive strength of kaolin geopolymers at 80°C for 1, 2, and 3 d. Kaolin geopolymers were stable in water, and strength results showed that the kaolin binder had adequate compressive strength with 12 mol/L of NaOH concentration. When the NaOH concentration increased, the SiO2/Na2O decreased. The increased Na2O content enhanced the dissolution of kaolin as shown in X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses. However, excess in this content was not beneficial for the strength development of kaolin geopolymers. In addition, there was the formation of more geopolymeric gel in 12 mol/L samples. The XRD pattern of the samples showed a higher amorphous content and a more geopolymer bonding existed as proved by FTIR analysis.

  5. Influenza virus neuraminidase (NA): a target for antivirals and vaccines.

    PubMed

    Jagadesh, Anitha; Salam, Abdul Ajees Abdul; Mudgal, Piya Paul; Arunkumar, Govindakarnavar

    2016-08-01

    Influenza, the most common infectious disease, poses a great threat to human health because of its highly contagious nature and fast transmissibility, often leading to high morbidity and mortality. Effective vaccination strategies may aid in the prevention and control of recurring epidemics and pandemics associated with this infectious disease. However, antigenic shifts and drifts are major concerns with influenza virus, requiring effective global monitoring and updating of vaccines. Current vaccines are standardized primarily based on the amount of hemagglutinin, a major surface antigen, which chiefly constitutes these preparations along with the varying amounts of neuraminidase (NA). Anti-influenza drugs targeting the active site of NA have been in use for more than a decade now. However, NA has not been approved as an effective antigenic component of the influenza vaccine because of standardization issues. Although some studies have suggested that NA antibodies are able to reduce the severity of the disease and induce a long-term and cross-protective immunity, a few major scientific issues need to be addressed prior to launching NA-based vaccines. Interestingly, an increasing number of studies have shown NA to be a promising target for future influenza vaccines. This review is an attempt to consolidate studies that reflect the strength of NA as a suitable vaccine target. The studies discussed in this article highlight NA as a potential influenza vaccine candidate and support taking the process of developing NA vaccines to the next stage. PMID:27255748

  6. Study of OSL in NaF: Ca,Cu

    NASA Astrophysics Data System (ADS)

    More, Y. K.; Wankhede, S. P.; Moharil, S. V.

    2013-06-01

    Sodium Fluoride containing Cu+ ions was prepared by R.A.P. followed by melt-quenching technique. Results on photo, thermo and optically stimulated luminescence in NaF:Ca,Cu are reported. OSL sensitivity of NaF:Ca,Cu is approximately 2 times than that of standard phosphor LMP. The rate of OSL depletion for 90% decay for NaF:Ca,Cu is 0.3 times as that of OSL phosphor LMP. NaF:Ca,Cu thus deserves much more attention than it has received up till now.

  7. Pion and kaon freezeout in NA44

    SciTech Connect

    NA44 Collaboration

    1994-12-01

    The NA44 spectrometer is optimized for the study of single and two-particle particle spectra near mid-rapidity for transverse momenta below {approx} 1 GeV/c. A large fraction of all pairs in the spectrometer`s acceptance are at low relative momenta, resulting in small statistical uncertainties on the extracted size parameters. In addition, the spectrometer`s clean particle identification allows the authors to measure correlation functions for pions, kaons, and protons. This contribution will concentrate on the source size parameters determined from pion and kaon correlation functions. These size parameters will be compared to calculations from the RQMD event generator and also interpreted in the context of a hydrodynamic model. Finally, the measured single particle spectra will be examined from the viewpoint of hydrodynamics.

  8. Mercury's Na Exosphere from MESSENGER Data

    NASA Technical Reports Server (NTRS)

    Killen, Rosemary M.; Burger, M. H.; Cassidy, T. A.; Sarantos, M.; Vervack, R. J.; McClintock, W. El; Merkel, A. W.; Sprague, A. L.; Solomon, S. C.

    2012-01-01

    MESSENGER entered orbit about Mercury on March 18, 2011. Since then, the Ultraviolet and Visible Spectrometer (UWS) channel of MESSENGER's Mercury Atmospheric and Surface Composition Spectrometer (MASCS) has been observing Mercury's exosphere nearly continuously. Daily measurements of Na brightness were fitted with non-uniform exospheric models. With Monte Carlo sampling we traced the trajectories of a representative number of test particles, generally one million per run per source process, until photoionization, escape from the gravitational well, or permanent sticking at the surface removed the atom from the simulation. Atoms were assumed to partially thermally accommodate on each encounter with the surface with accommodation coefficient 0.25. Runs for different assumed source processes are run separately, scaled and co-added. Once these model results were saved onto a 3D grid, we ran lines of sight from the MESSENGER spacecraft :0 infinity using the SPICE kernels and we computed brightness integrals. Note that only particles that contribute to the measurement can be constrained with our method. Atoms and molecules produced on the nightside must escape the shadow in order to scatter light if the excitation process is resonant-light scattering, as assumed here. The aggregate distribution of Na atoms fits a 1200 K gas, with a PSD distribution, along with a hotter component. Our models constrain the hot component, assumed to be impact vaporization, to be emitted with a 2500 K Maxwellian. Most orbits show a dawnside enhancement in the hot component broadly spread over the leading hemisphere. However, on some dates there is no dawn/dusk asymmetry. The portion of the hot/cold source appears to be highly variable.

  9. The naïve intuitive statistician: a naïve sampling model of intuitive confidence intervals.

    PubMed

    Juslin, Peter; Winman, Anders; Hansson, Patrik

    2007-07-01

    The perspective of the naïve intuitive statistician is outlined and applied to explain overconfidence when people produce intuitive confidence intervals and why this format leads to more overconfidence than other formally equivalent formats. The naïve sampling model implies that people accurately describe the sample information they have but are naïve in the sense that they uncritically take sample properties as estimates of population properties. A review demonstrates that the naïve sampling model accounts for the robust and important findings in previous research as well as provides novel predictions that are confirmed, including a way to minimize the overconfidence with interval production. The authors discuss the naïve sampling model as a representative of models inspired by the naïve intuitive statistician. PMID:17638502

  10. Melting properties of radiation-induced Na and Cl2 precipitates in ultra-heavily irradiated NaCl

    NASA Astrophysics Data System (ADS)

    Sugonyako, A. V.; Vainshtein, D. I.; den Hartog, H. P.; Turkin, A. A.; den Hartog, H. W.

    2005-01-01

    Exposure of NaCl to high doses of ionizing radiation leads to the formation of nano-particles of metallic Na, very small chlorine precipitates, vacancy voids, and dislocations. A useful way to monitor the stage of the damage formation process is measuring the latent heat of melting of the Na-particles (100 °C) and chlorine precipitates (-101 °C). In this paper we will present data, showing that for doses in the range of TRad (1010 Gy) the concentration of radiolytic Na may become very large. Even in pure samples, we have converted more than 20% of all NaCl molecules into metallic Na and chlorine, but often higher percentages can be achieved. In this paper we will present new data obtained for ultra-high irradiation doses and a first attempt will be made to understand the results.

  11. Attenuation of Na/K-ATPase Mediated Oxidant Amplification with pNaKtide Ameliorates Experimental Uremic Cardiomyopathy

    PubMed Central

    Liu, Jiang; Tian, Jiang; Chaudhry, Muhammad; Maxwell, Kyle; Yan, Yanling; Wang, Xiaoliang; Shah, Preeya T.; Khawaja, Asad A.; Martin, Rebecca; Robinette, Tylor J.; El-Hamdani, Adee; Dodrill, Michael W.; Sodhi, Komal; Drummond, Christopher A.; Haller, Steven T.; Kennedy, David J.; Abraham, Nader G.; Xie, Zijian; Shapiro, Joseph I.

    2016-01-01

    We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic cardiomyopathy reversed many of the phenotypical features. Attenuation of Na/K-ATPase oxidant amplification may be a potential strategy for clinical therapy of this disorder. PMID:27698370

  12. RNA adducts with Na 2SeO 4 and Na 2SeO 3 - Stability and structural features

    NASA Astrophysics Data System (ADS)

    Nafisi, Shohreh; Manouchehri, Firouzeh; Montazeri, Maryam

    2011-12-01

    Selenium compounds are widely available in dietary supplements and have been extensively studied for their antioxidant and anticancer properties. Low blood Se levels were found to be associated with an increased incidence and mortality from various types of cancers. Although many in vivo and clinical trials have been conducted using these compounds, their biochemical and chemical mechanisms of efficacy are the focus of much current research. This study was designed to examine the interaction of Na 2SeO 4 and Na 2SeO 3 with RNA in aqueous solution at physiological conditions, using a constant RNA concentration (6.25 mM) and various sodium selenate and sodium selenite/polynucleotide (phosphate) ratios of 1/80, 1/40, 1/20, 1/10, 1/5, 1/2 and 1/1. Fourier transform infrared, UV-Visible spectroscopic methods were used to determine the drug binding modes, the binding constants, and the stability of Na 2SeO 4 and Na 2SeO 3-RNA complexes in aqueous solution. Spectroscopic evidence showed that Na 2SeO 4 and Na 2SeO 3 bind to the major and minor grooves of RNA ( via G, A and U bases) with some degree of the Se-phosphate (PO 2) interaction for both compounds with overall binding constants of K(Na 2SeO 4-RNA) = 8.34 × 10 3 and K(Na 2SeO 3-RNA) = 4.57 × 10 3 M -1. The order of selenium salts-biopolymer stability was Na 2SeO 4-RNA > Na 2SeO 3-RNA. RNA aggregations occurred at higher selenium concentrations. No biopolymer conformational changes were observed upon Na 2SeO 4 and Na 2SeO 3 interactions, while RNA remains in the A-family structure.

  13. Solubility of MgO in MgCl{sub 2}-NaCl-NaF melts

    SciTech Connect

    Mediaas, H.; Vinstad, J.E.; Oestvold, T.

    1996-10-01

    The solubility of MgO in MgCl{sub 2}-NaCl-NaF melts has been measured for melts with varying NaF concentration for x{sub MgCl{sub 2}} = 0.10 and 0.63 and for x{sub MgCl{sub 2}}/x{sub NaCl} = 1.70. Melt samples have been analyzed by carbothermal reduction (Leco TC-436) for total oxide content. The oxide content in the binary melt MgCl{sub 2}-NaCl was also analyzed by Iodometric titration. The results indicate two different oxide-containing species, denoted MgOCl and MgOF, in the solidified samples withdrawn from the melt. The latter appears only in fluoride-containing melts, but may, however, also contain chloride ions. The oxide solubility is increasing with increasing concentration of Mg{sup 2+} in both MgCl{sub 2}-NaCl and MgCl{sub 2}-NaCl-NaF melts. The solubility of MgO is always higher in fluoride containing melts at the same Mg{sup 2+} concentration. In the systems concentrated in MgCl{sub 2}, the increase in oxide solubility as function of x{sub NaF} is more pronounced than what is predicted from a simple model calculation. The increase is much smaller in the x{sub NaF} < 0.2 range for small MgCl{sub 2} contents than predicted from the same model calculation. The introduction of 1.7 mol% NaF to an industrial electrolyte does not seem to change the oxide solubility significantly. In such an electrolyte, where x{sub MgCl{sub 2}} {approx_equal} 0.1, the data gives a constant oxide solubility around 10 ppm O up to 5 mol% NaF.

  14. Elevated [Cl-]i, and [Na+]i inhibit Na+, K+, Cl- cotransport by different mechanisms in squid giant axons

    PubMed Central

    1996-01-01

    Bumetanide-sensitive (BS) unidirectional fluxes of (36)Cl- or (22)Na+ were measured in internally dialyzed squid giant axons while varying the intra- or extracellular concentrations of Na+ and/or Cl-. Raising either [Cl-]i or [Na+]i resulted in a concentration-dependent reduction of the BS influx of both (36)Cl- and (22)Na+. Raising [Cl-]i above 200 mM completely blocked BS influxes. However, raising [Na+]i to 290 mM resulted in saturable but incomplete inhibition of both BS Na+ influx and BS Cl- influx. The consequences of varying intracellular Cl- on cotransporter effluxes were complex. At lower [Cl-]i values (below 100 mM) intracellular Cl- activated cotransporter effluxes. Surprisingly, however, raising [Cl-]i levels > 125 mM resulted in a [Cl-]i-dependent inhibition of BS effluxes of both Na+ and Cl-. On the other hand, raising [Na+]i resulted only in the activation of the BS Na+ efflux; intracellular Na+ did not inhibit BS efflux even at 290 mM. The inhibitory effects of intracellular Na+ on cotransporter-mediated influxes, and lack of inhibitory effects on BS effluxes, are consistent with the trans-side inhibition expected for an ordered binding/release model of cotransporter operation. However, the inhibitory effects of intracellular Cl- on both influxes and effluxes are not explained by such a model. These data suggest that Cl may interact with an intracellular site (or sites), which does not mediate Cl transport, but does modulate the transport activity of the Na+, K+, Cl- cotransporter. PMID:8833345

  15. Elevated [Cl-]i, and [Na+]i inhibit Na+, K+, Cl- cotransport by different mechanisms in squid giant axons.

    PubMed

    Breitwieser, G E; Altamirano, A A; Russell, J M

    1996-02-01

    Bumetanide-sensitive (BS) unidirectional fluxes of (36)Cl- or (22)Na+ were measured in internally dialyzed squid giant axons while varying the intra- or extracellular concentrations of Na+ and/or Cl-. Raising either [Cl-]i or [Na+]i resulted in a concentration-dependent reduction of the BS influx of both (36)Cl- and (22)Na+. Raising [Cl-]i above 200 mM completely blocked BS influxes. However, raising [Na+]i to 290 mM resulted in saturable but incomplete inhibition of both BS Na+ influx and BS Cl- influx. The consequences of varying intracellular Cl- on cotransporter effluxes were complex. At lower [Cl-]i values (below 100 mM) intracellular Cl- activated cotransporter effluxes. Surprisingly, however, raising [Cl-]i levels > 125 mM resulted in a [Cl-]i-dependent inhibition of BS effluxes of both Na+ and Cl-. On the other hand, raising [Na+]i resulted only in the activation of the BS Na+ efflux; intracellular Na+ did not inhibit BS efflux even at 290 mM. The inhibitory effects of intracellular Na+ on cotransporter-mediated influxes, and lack of inhibitory effects on BS effluxes, are consistent with the trans-side inhibition expected for an ordered binding/release model of cotransporter operation. However, the inhibitory effects of intracellular Cl- on both influxes and effluxes are not explained by such a model. These data suggest that Cl may interact with an intracellular site (or sites), which does not mediate Cl transport, but does modulate the transport activity of the Na+, K+, Cl- cotransporter.

  16. A 23Na magic angle spinning nuclear magnetic resonance, XANES, and high-temperature X-ray diffraction study of NaUO3, Na4UO5, and Na2U2O7.

    PubMed

    Smith, A L; Raison, P E; Martel, L; Charpentier, T; Farnan, I; Prieur, D; Hennig, C; Scheinost, A C; Konings, R J M; Cheetham, A K

    2014-01-01

    The valence state of uranium has been confirmed for the three sodium uranates NaU(V)O3/[Rn](5f(1)), Na4U(VI)O5/[Rn](5f(0)), and Na2U(VI)2O7/[Rn](5f(0)), using X-ray absorption near-edge structure (XANES) spectroscopy. Solid-state (23)Na magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been performed for the first time, yielding chemical shifts at -29.1 (NaUO3), 15.1 (Na4UO5), and -14.1 and -19 ppm (Na1 8-fold coordinated and Na2 7-fold coordinated in Na2U2O7), respectively. The [Rn]5f(1) electronic structure of uranium in NaUO3 causes a paramagnetic shift in comparison to Na4UO5 and Na2U2O7, where the electronic structure is [Rn]5f(0). A (23)Na multi quantum magic angle spinning (MQMAS) study on Na2U2O7 has confirmed a monoclinic rather than rhombohedral structure with evidence for two distinct Na sites. DFT calculations of the NMR parameters on the nonmagnetic compounds Na4UO5 and Na2U2O7 have permitted the differentiation between the two Na sites of the Na2U2O7 structure. The linear thermal expansion coefficients of all three compounds have been determined using high-temperature X-ray diffraction: αa = 22.7 × 10(-6) K(-1), αb = 12.9 × 10(-6) K(-1), αc = 16.2 × 10(-6) K(-1), and αvol = 52.8 × 10(-6) K(-1) for NaUO3 in the range 298-1273 K; αa = 37.1 × 10(-6) K(-1), αc = 6.2 × 10(-6) K(-1), and αvol = 81.8 × 10(-6) K(-1) for Na4UO5 in the range 298-1073 K; αa = 6.7 × 10(-6) K(-1), αb = 14.4 × 10(-6) K(-1), αc = 26.8 × 10(-6) K(-1), αβ = -7.8 × 10(-6) K(-1), and αvol = -217.6 × 10(-6) K(-1) for Na2U2O7 in the range 298-573 K. The α to β phase transition reported for the last compound above about 600 K was not observed in the present studies, either by high-temperature X-ray diffraction or by differential scanning calorimetry. PMID:24350659

  17. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  18. Estimating the hydrogen ion concentration in concentrated NaCl and Na{sub 2}SO{sub 4} electrolytes

    SciTech Connect

    Rai, D.; Felmy, A.R.; Juracich, S.P.; Rao, F.

    1995-06-01

    Combination glass electrodes were tested for determining H{sup +} concentrations in concentrated pure and mixed NaCl and Na{sub 2}SO{sub 4} solutions, as well as natural brine systems. NaCl, Na{sub 2}SO{sub 4}, and mixtures of NaCl and Na{sub 2}SO{sub 4} solutions were analyzed. Correction factors for estimating pC{sub H}{sup +} (negative logarithm of H{sup +} concentration) were determined from measured/observed pH values. Required Gran-type titrations were done with HCl and/or NaOH. The titration method is described and a step-by-step procedure provided; it has been used previously for determining pC{sub H}{sup +} values of synthetic chloride-dominated brines. Precautions are required to determine correction factors for electrolytes that react with H{sup +} or OH{sup {minus}} [sulfate brines for titration with acid; magnesium brines for titration with base because of precipitation of Mg(OH)2]. Correction factors A (pC{sub H}{sup +} = pH{sub ob} + A) from HCl titrations were similar to those from NaOH titrations where the concentration of free H{sup +} was calculated using a thermodynamic model. These values should be applicable to solns with a very large range in measured pH values (2 to 12). Because a large number of solns were titrated with HCl and the A values are similar for HCl and NaOH titrations, the A values for NaCl and Na2SO4 solns were fit as a function of molality to allow extrapolation. For NaCl solns 0 to 6.0 M, A can be obtained by multiplying the molality by 0.159. For Na2SO4 solns 0 to 2.0 M, the values of A can be obtained from (0.221 {minus} 0.549X + 0.201X{sup 2}), where X is the molality of Na{sub 2}SO{sub 4}. Orion-Ross electrode evaluations indicated that the A values did not differ significantly for different electrodes. Results suggest that the data in this report can be used to estimate A values for different NaCl and Na{sub 2}SO{sub 4} solns even for noncalibrated electrodes.

  19. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  20. Central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) in sodium bioenergetics of Vibrio cholerae.

    PubMed

    Steuber, Julia; Halang, Petra; Vorburger, Thomas; Steffen, Wojtek; Vohl, Georg; Fritz, Günter

    2014-12-01

    Vibrio cholerae is a Gram-negative bacterium that lives in brackish or sea water environments. Strains of V. cholerae carrying the pathogenicity islands infect the human gut and cause the fatal disease cholera. Vibrio cholerae maintains a Na(+) gradient at its cytoplasmic membrane that drives substrate uptake, motility, and efflux of antibiotics. Here, we summarize the major Na(+)-dependent transport processes and describe the central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), a primary Na(+) pump, in maintaining a Na(+)-motive force. The Na(+)-NQR is a membrane protein complex with a mass of about 220 kDa that couples the exergonic oxidation of NADH to the transport of Na(+) across the cytoplasmic membrane. We describe the molecular architecture of this respiratory complex and summarize the findings how electron transport might be coupled to Na(+)-translocation. Moreover, recent advances in the determination of the three-dimensional structure of this complex are reported.

  1. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light. PMID:26353495

  2. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light.

  3. Background study of NaI(Tl) crystals for the KIMS-NaI experiment

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; Adhikari, G.; Choi, S.; Ha, C.; Hahn, I. S.; Jeon, EJ; Joo, H. W.; Kang, W. G.; Kim, H. J.; Kim, H. O.; Kim, K. W.; Kim, N. Y.; Kim, S. K.; Kim, Y. D.; Kim, Y. H.; Lee, H. S.; Lee, J. H.; Lee, M. H.; Leonard, D. S.; Li, J.; Oh, S. Y.; Olsen, S. L.; Park, H. K.; Park, H. S.; Park, K. S.; So, J. H.; Yoon, Y. S.

    2016-05-01

    The DAMA experiment has reported an annual-modulation signal in an array of low-background NaI(Tl) scintillating crystals that may be caused by WIMP-nucleon interactions. However, to date there has been no direct confirmation of this result that uses the same taget nuclides. The Korea Invisible Mass Search (KIMS) collaboration has been engaged in an extensive R&D program to grow ultra-low background NaI(Tl) crystals for use as a direct test of the DAMA result using same nuclide targets. Six crystals were grown from different powders in order to understand mechanisms of internal background contaminations and to reduce their effects. Studies of internal backgrounds in these crystals were performed with the ultimate goal of reducing internal background contamination levels to 1 dru at 2 keV.

  4. Kinetics and stoichiometry of coupled Na efflux and Ca influx (Na/Ca exchange) in barnacle muscle cells

    PubMed Central

    1989-01-01

    Coupled Na+ exit/Ca2+ entry (Na/Ca exchange operating in the Ca2+ influx mode) was studied in giant barnacle muscle cells by measuring 22Na+ efflux and 45Ca2+ influx in internally perfused, ATP-fueled cells in which the Na+ pump was poisoned by 0.1 mM ouabain. Internal free Ca2+, [Ca2+]i, was controlled with a Ca-EGTA buffering system containing 8 mM EGTA and varying amounts of Ca2+. Ca2+ sequestration in internal stores was inhibited with caffeine and a mitochondrial uncoupler (FCCP). To maximize conditions for Ca2+ influx mode Na/Ca exchange, and to eliminate tracer Na/Na exchange, all of the external Na+ in the standard Na+ sea water (NaSW) was replaced by Tris or Li+ (Tris-SW or LiSW, respectively). In both Na-free solutions an external Ca2+ (Cao)-dependent Na+ efflux was observed when [Ca2+]i was increased above 10(-8) M; this efflux was half-maximally activated by [Ca2+]i = 0.3 microM (LiSW) to 0.7 microM (Tris-SW). The Cao-dependent Na+ efflux was half-maximally activated by [Ca2+]o = 2.0 mM in LiSW and 7.2 mM in Tris-SW; at saturating [Ca2+]o, [Ca2+]i, and [Na+]i the maximal (calculated) Cao-dependent Na+ efflux was approximately 75 pmol#cm2.s. This efflux was inhibited by external Na+ and La3+ with IC50's of approximately 125 and 0.4 mM, respectively. A Nai-dependent Ca2+ influx was also observed in Tris-SW. This Ca2+ influx also required [Ca2+]i greater than 10(-8) M. Internal Ca2+ activated a Nai-independent Ca2+ influx from LiSW (tracer Ca/Ca exchange), but in Tris-SW virtually all of the Cai-activated Ca2+ influx was Nai-dependent (Na/Ca exchange). Half-maximal activation was observed with [Na+]i = 30 mM. The fact that internal Ca2+ activates both a Cao-dependent Na+ efflux and a Nai- dependent Ca2+ influx in Tris-SW implies that these two fluxes are coupled; the activating (intracellular) Ca2+ does not appear to be transported by the exchanger. The maximal (calculated) Nai-dependent Ca2+ influx was -25 pmol/cm2.s. At various [Na+]i between 6 and 106 m

  5. North America and South America (NA-SA) neuropathy project.

    PubMed

    Pasnoor, Mamatha; Nascimento, Osvaldo J M; Trivedi, Jaya; Wolfe, Gil I; Nations, Sharon; Herbelin, Laura; de Freitas, M G; Quintanilha, Giseli; Khan, Saud; Dimachkie, Mazen; Barohn, Richard

    2013-08-01

    Peripheral neuropathy is a common neurological disorder. There may be important differences and similarities in the diagnosis of peripheral neuropathy between North America (NA) and South America (SA). Neuromuscular databases were searched for neuropathy diagnosis at two North American sites, University of Kansas Medical Center and University of Texas Southwestern Medical Center, and one South American site, Federal Fluminense University in Brazil. All patients were included into one of the six major categories: immune-mediated, diabetic, hereditary, infectious/inflammatory, systemic/metabolic/toxic (not diabetic) and cryptogenic. A comparison of the number of patients in each category was made between North America and South America databases. Total number of cases in North America was 1090 and in South America was 1034 [immune-mediated: NA 215 (19.7%), SA 191 (18%); diabetic: NA 148 (13.5%), SA 236 (23%); hereditary: NA 292 (26.7%), SA 103 (10%); infectious/inflammatory: NA 53 (4.8%), SA 141 (14%); systemic/metabolic/toxic: NA 71 (6.5%), SA 124 (12%); cryptogenic: NA 311 (28.5%), SA 239 (23%)]. Some specific neuropathy comparisons were hereditary neuropathies [Charcot-Marie-Tooth (CMT) cases] in NA 246/292 (84.2%) and SA 60/103 (58%); familial amyloid neuropathy in SA 31/103 (30%) and none in NA. Among infectious neuropathies, cases of human T-lymphotropic virus type 1 (HTLV-1) neuropathy in SA were 36/141(25%), Chagas disease in SA were 13/141(9%) and none for either in NA; cases of neuropathy due to leprosy in NA were 26/53 (49%) and in SA were 39/141(28%). South American tertiary care centers are more likely to see patients with infectious, diabetic and hereditary disorders such as familial amyloid neuropathies. North American tertiary centers are more likely to see patients with CMT. Immune neuropathies and cryptogenic neuropathies were seen equally in North America and South America.

  6. 33 CFR 147.833 - Na Kika FDS safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description....

  7. 33 CFR 147.833 - Na Kika FDS safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description....

  8. Transepithelial Na+ transport and the intracellular fluids: a computer study.

    PubMed

    Civan, M M; Bookman, R J

    1982-01-01

    Computer simulations of tight epithelia under three experimental conditions have been carried out, using the rheogenic nonlinear model of Lew, Ferreira and Moura (Proc. Roy. Soc. London. B 206:53-83, 1979) based largely on the formulation of Koefoed-Johnsen and Ussing (Acta Physiol. Scand. 42: 298-308. 1958). First, analysis of the transition between the short-circuited and open-circuited states has indicated that (i) apical Cl- permeability is a critical parameter requiring experimental definition in order to analyze cell volume regulation, and (ii) contrary to certain experimental reports, intracellular Na+ concentration (ccNa) is expected to be a strong function of transepithelial clamping voltage. Second, analysis of the effects of lowering serosal K+ concentration (csK) indicates that the basic model cannot simulate several well-documented observations; these defects can be overcome, at least qualitatively, by modifying the model to take account of the negative feedback interaction likely to exist between the apical Na+ permeability and ccNa. Third, analysis of the strongly supports the concept that osmotically induced permeability changes in the apical intercellular junctions play a physiological role in conserving the body's stores of NaCl. The analyses also demonstrate that the importance of Na+ entry across the basolateral membrane is strongly dependent upon transepithelial potential, cmNa and csK; under certain conditions, net Na+ entry could be appreciably greater across the basolateral than across the apical membrane.

  9. Adaptation of Tobacco Cells to NaCl 1

    PubMed Central

    Binzel, Marla L.; Hasegawa, Paul M.; Handa, Avtar K.; Bressan, Ray A.

    1985-01-01

    Cell lines of tobacco (Nicotiana tabacum L. var Wisconsin 38) were obtained which are adapted to grow in media with varying concentrations of NaCl, up to 35 grams per liter (599 millimolar). Salt-adapted cells exhibited enhanced abilities to gain both fresh and dry weight in the presence of NaCl compared to cells which were growing in medium without NaCl (unadapted cells). Tolerance of unadapted cells and cells adapted to 10 grams per liter NaCl was influenced by the stage of growth, with the highest degree of tolerance exhibited by cells in the exponential phase. Cell osmotic potential and turgor varied through the growth cycle of unadapted cells and cells at all levels of adaptation, with maximum turgor occurring at approximately the onset of exponential fresh weight accumulation. Adaptation to NaCl led to reduced cell expansion and fresh weight gain, while dry weight gain remained unaffected. This reduction in cell expansion was not due to failure of the cells to maintain turgor since cells adapted to NaCl underwent osmotic adjustment in excess of the change in water potential caused by the addition of NaCl to the medium. Tolerance of the adapted cells, as indicated by fresh or dry weight gain, did not increase proportionately with the increase in turgor. Adaptation of these glycophytic cells to NaCl appears to involve mechanisms which result in an altered relationship between turgor and cell expansion. Images Fig. 3 PMID:16664356

  10. The pea gene NA encodes ent-kaurenoic acid oxidase.

    PubMed

    Davidson, Sandra E; Elliott, Robert C; Helliwell, Chris A; Poole, Andrew T; Reid, James B

    2003-01-01

    The gibberellin (GA)-deficient dwarf na mutant in pea (Pisum sativum) has severely reduced internode elongation, reduced root growth, and decreased leaflet size. However, the seeds develop normally. Two genes, PsKAO1 and PsKAO2, encoding cytochrome P450 monooxygenases of the subfamily CYP88A were isolated. Both PsKAO1 and PsKAO2 had ent-kaurenoic acid oxidase (KAO) activity, catalyzing the three steps of the GA biosynthetic pathway from ent-kaurenoic acid to GA(12) when expressed in yeast (Saccharomyces cerevisiae). In addition to the intermediates ent-7alpha-hydroxykaurenoic acid and GA(12)-aldehyde, some additional products of the pea KAO activity were detected, including ent-6alpha,7alpha-dihydroxykaurenoic acid and 7beta-hydroxykaurenolide. The NA gene encodes PsKAO1, because in two independent mutant alleles, na-1 and na-2, PsKAO1 had altered sequences and the five-base deletion in PsKAO1 associated with the na-1 allele cosegregated with the dwarf na phenotype. PsKAO1 was expressed in the stem, apical bud, leaf, pod, and root, organs in which GA levels have previously been shown to be reduced in na plants. PsKAO2 was expressed only in seeds and this may explain the normal seed development and normal GA biosynthesis in seeds of na plants.

  11. Direct Measurement of {sup 21}Na+{alpha} Stellar Reaction

    SciTech Connect

    Binh, D. N.; Kubono, S.; Yamaguchi, H.; Hayakawa, S.; Hashimoto, T.; Kahl, D.; Teranishi, T.; Iwasa, N.; Kume, N.; Kato, S.; Khiem, L. H.; Tho, N. T.; Wakabayashi, Y.

    2010-08-12

    The measurement of the resonant alpha scattering and the {sup 21}Na({alpha}, p) reaction were performed for the first time in inverse kinematics with the thick target method using a {sup 21}Na radioisotope (RI) beam. This paper reports the current result of alpha scattering measurement and its astrophysics implication.

  12. Moderate temperature rechargeable NaNiS2 cells

    NASA Technical Reports Server (NTRS)

    Abraham, K. M.

    1983-01-01

    A rechargeable sodium battery of the configuration, liquid Na/beta double prime -Al2O3/molten NaAlCl4, NiS2, operating in the temperature range of 170 to 190 C, is described. This battery is capable of delivering or = to 50 W-hr/1b and 1000 deep discharge/charge cycles.

  13. Molecular Mechanisms of Bone 18F-NaF Deposition

    PubMed Central

    Czernin, Johannes; Satyamurthy, Nagichettiar; Schiepers, Christiaan

    2011-01-01

    There is renewed interest in 18F-NaF bone imaging with PET or PET/CT. The current brief discussion focuses on the molecular mechanisms of 18F-NaF deposition in bone and presents model-based approaches to quantifying bone perfusion and metabolism in the context of preclinical and clinical applications of bone imaging with PET. PMID:21078790

  14. Naïve Bayes classification in R

    PubMed Central

    2016-01-01

    Naïve Bayes classification is a kind of simple probabilistic classification methods based on Bayes’ theorem with the assumption of independence between features. The model is trained on training dataset to make predictions by predict() function. This article introduces two functions naiveBayes() and train() for the performance of Naïve Bayes classification. PMID:27429967

  15. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells

    PubMed Central

    Vereninov, Igor A.; Yurinskaya, Valentina E.; Model, Michael A.; Vereninov, Alexey A.

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1–10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324

  16. Extending 3-Frequency Na Doppler Lidar Wind and Temperature Measurements into Lower Atmosphere with Na Double-Edge Magneto-Optic Filters (Na-DEMOF)

    NASA Astrophysics Data System (ADS)

    Huang, W.; Chu, X.; Wiig, J.; Williams, B. P.; Harrell, S.; She, C.

    2008-12-01

    An important atmospheric process is the wave coupling among different layers. It is crucial to trace waves from their source regions in the lower atmosphere to their dissipation regions in the middle and upper atmosphere. This requires the profiling of wind and temperature simultaneously from the lower to the upper atmosphere. Utilizing Doppler shift and Doppler broadening effects, various types of Doppler lidars can measure wind and temperature in different atmospheric regions. However, none of the single lidars is able to profile both variables throughout the atmosphere. Resonance fluorescence Na Doppler lidars measure wind and temperature simultaneously in the mesosphere and lower thermosphere. They have made significant contributions to the study of wave dynamics. Unfortunately, their measurements are limited to 80-105 km where the trace gas Na atoms are available. We proposed to incorporate a Na double-edge magneto-optic filter (Na-DEMOF) into the receiver of a 3-frequency Na Doppler lidar to extend its wind and temperature measurements into the lower atmosphere. Two prototypes based on cold- and hot-cell designs were constructed and characterized with laboratory tests. The hot-cell filter showed superior performances than the cold-cell containing buffer gas. The hot-cell Na-DEMOF was also successfully modeled by quantum mechanics calculations. Lidar simulations were conducted for analysis of measurement errors in the altitude range of 15-50 km with the hot-cell filter developed. Field test using the hot-cell Na-DEMOF with the Colorado State University Na lidar is under its way and the initial results will be reported and compared to lidar simulation.

  17. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells.

    PubMed

    Vereninov, Igor A; Yurinskaya, Valentina E; Model, Michael A; Vereninov, Alexey A

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1-10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324

  18. Feasibility study for a secondary Na/S battery

    NASA Technical Reports Server (NTRS)

    Abraham, K. M.; Schiff, R.; Brummer, S. B.

    1979-01-01

    The feasibility of a moderate temperature Na battery was studied. This battery is to operate at a temperature in the range of 100-150 C. Two kinds of cathode were investigated: (1) a soluble S cathode consisting of a solution of Na2Sn in an organic solvent and (2) an insoluble S cathode consisting of a transition metal dichalcogenide in contact with a Na(+)ion conducting electrolyte. Four amide solvents, dimethyl acetamide, diethyl acetamide, N-methyl acetamide and acetamide, were investigated as possible solvents for the soluble S cathode. Results of stability and electrochemical studies using these solvents are presented. The dialkyl substituted amides were found to be superior. Although the alcohol 1,3-cyclohexanediol was found to be stable in the presence of Na2Sn at 130 C, its Na2Sn solutions did not appear to have suitable electrochemical properties.

  19. Trisodium citrate, Na3(C6H5O7)

    PubMed Central

    Rammohan, Alagappa; Kaduk, James A.

    2016-01-01

    The crystal structure of anhydrous tris­odium citrate, Na3(C6H5O7), has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory (DFT). There are two independent five-coordinate Na+ and one six-coordinate Na+ cations in the asymmetric unit. The [NaO5] and [NaO6] polyhedra share edges and corners to form a three-dimensional framework. There are channels parallel to the a and b axes in which the remainder of the citrate anions reside. The only hydrogen bonds are an intra­molecular one between the hy­droxy group and one of the terminal carboxyl­ate O atoms and an intermolecular one between a methylene group and the hydroxyl O atom. PMID:27308044

  20. NaCl-induced accelerated oxidation of chromium

    SciTech Connect

    Shinata, Y.; Nishi, Y.

    1986-10-01

    This paper describes new phenomena about chloride-induced ;accelerated oxidation of chromium. Thermal analysis was adopted to examine the oxidation, which was studied particularly in the case of NaCl. The presence of NaCl remarkably accelerates the oxidation of chromium. The process occurs below the melting point of NaCl, and the main reaction product is Cr/sub 2/O/sub 3/. In the accelerated oxidation NaCl plays a catalytic role because it is not consumed significantly in the process. DTA analysis reveals that the heat of reaction also accelerates the rate of oxidation, especially at an early stage of the reaction. The accelerated oxidation takes place similarly under the presence of chlorides other than NaCl, but the oxidation rate depends on the kind of salt. Therefore the Cl/sup -/ anion plays an important role in the process, while the nature of the cation affects the rate of acceleration.

  1. DIANA NaI-Detector Energy Calibration

    NASA Astrophysics Data System (ADS)

    O'Connor, Kyle; Elofson, David; Lewis, Codie; O'Brien, Erin; Buggelli, Kelsey; Miller, Nevin; O'Rielly, Grant; Maxtagg Collaboration

    2014-09-01

    The DIANA detector is being used for measurements of near threshold pion photoproduction and high-energy nuclear Compton scattering being performed at the MAX-lab tagged photon facility in Lund, Sweden. Accurate energy calibrations are essential for determining the final results from both of these experiments. An energy calibration has been performed for DIANA, a single-crystal, large-volume, NaI detector. This calibration was made by placing the detector directly in the tagged photon beam with energies from 145 to 165 MeV and fitting the detector response to the known photon energies. The DIANA crystal is instrumented with 19 PMTs, pedestal corrections were applied and the PMTs were gain matched in order to combine the readout value from each PMT and determine the final detector response. This response was fitted to the tagged photon energies to provide the final energy calibration. The calibrations were performed with two triggers; one from the detector itself and one provided by the photon tagger. The quality of the final calibration fit and the energy resolution of the detector, σ ~ 2 . 4 MeV, will be shown.

  2. Endurance testing with Li/Na electrolyte

    SciTech Connect

    Ong, E.T.; Remick, R.J.; Sishtla, C.I.

    1996-12-31

    The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

  3. Genome Sequences of Cupriavidus metallidurans Strains NA1, NA4, and NE12, Isolated from Space Equipment

    PubMed Central

    Monsieurs, Pieter; Mijnendonckx, Kristel; Provoost, Ann; Venkateswaran, Kasthuri; Ott, C. Mark; Leys, Natalie

    2014-01-01

    Cupriavidus metallidurans NA1, NA4, and NE12 were isolated from space and spacecraft-associated environments. Here, we report their draft genome sequences with the aim of gaining insight into their potential to adapt to these environments. PMID:25059868

  4. Production of Secondary Radioactive 21Na Beam for the Study of 21Na(α,p)24Mg Stellar Reaction

    NASA Astrophysics Data System (ADS)

    Binh, Dam Nguyen; Khiem, Le Hong; Kubono, S.; Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Kim, A.

    2008-04-01

    The availability of radioactive beams has produced great opportunities for advances in our understanding of the nucleosynthesis occurring in stellar explosions such as novae, X-ray burst and supernovae. By using an in-flight low-energy radioisotope beam separator (CRIB) at Center for Nuclear Study (CNS), University of Tokyo, we have successfully produced the 21Na proton-rich beam for the study of 21Na(α,p)24Mg reaction which is related to the astrophysically important production of 22Na in the stellar explosive environments. Since it is the first time when this reaction is studied experimentally, we have performed a test experiment to produce the 21Na beam and to estimate the feasibility of the experimental study of 21Na(α,p)24Mg reaction.

  5. Brefeldin A inhibition of apical Na+ channels in epithelia.

    PubMed

    Fisher, R S; Grillo, F G; Sariban-Sohraby, S

    1996-01-01

    Brefeldin A (BFA) is used to probe trafficking of proteins through the central vacuolar system (CVS) in a variety of cells. Transepithelial Na+ transport by high-resistance epithelia, such as A6 cultured cells, is inhibited by BFA. Apical Na+ channels, as well as basolateral pumps and K+ channels, are complex proteins that probably traverse the CVS for routing to the plasma membrane. BFA (5 micrograms/ml) decreases transepithelial Na+ current near zero and increases resistance reversibly after 4 h. Longer exposures are toxic. When tissues were treated for 20 h with 0.2 microgram/ml BFA, Na+ transport also was reversibly inhibited. Using noise analysis, we found that BFA drastically reduced apical Na+ channel density. The increase in single channel current was consistent with cell hyperpolarization. After apical permeabilization with nystatin, changes in transepithelial current reflect changes in basolateral membrane transport. Transport at this membrane was inhibited by ouabain and cycloheximide, but not by BFA. After BFA, aldosterone was ineffective, suggesting that an intact CVS is required for stimulation by this hormone. Thus BFA inhibition of Na+ transport is localized at the apical membrane. Implications for channel turnover as a mechanism for regulating the Na+ transport rate are discussed.

  6. Hormonal regulation of Na -K -ATPase in cultured epithelial cells

    SciTech Connect

    Johnson, J.P.; Jones, D.; Wiesmann, W.P.

    1986-08-01

    Aldosterone and insulin stimulate Na transport through mechanisms involving protein synthesis. Na -K -ATPase has been implicated in the action of both hormones. The authors examined the effect of aldosterone and insulin on Na -K -ATPase in epithelial cells in culture derived from toad urinary bladder (TB6C) and toad kidney (A6). Aldosterone, but not insulin, increases short-circuit current (I/sub sc/) in TB6C cells. Aldosterone increases Na -K -(TSP)ATPase activity after 18 h of incubation, but no effect can be seen at 3 and 6 h. Amiloride, which inhibits aldosterone-induced increases in I/sub sc/, has no effect on either basal or aldosterone stimulated enzyme activity. Both aldosterone and insulin increase I/sub sc/ in A6 cells and when added together are synergistic. Aldosterone stimulates enzyme activity in A6 cells, but insulin alone has no effect. However, aldosterone and insulin together stimulate enzyme activity more than aldosterone alone. It appears that stimulation of Na -K -ATPase activity is involved in aldosterone action in both cell lines but does not appear to be due to increased Na entry, since enhanced enzyme activity is not inhibited by amiloride. In contrast, insulin alone has no direct effect on Na -K -ATPase, although the increased enzyme activity following both agents in combination may explain their synergism on I/sub sc/.

  7. Rat hepatocytes exhibit basolateral Na+/HCO/sub 3/- cotransport

    SciTech Connect

    Renner, E.L.; Lake, J.R.; Scharschmidt, B.F.; Zimmerli, B.; Meier, P.J.

    1989-04-01

    Primary cultures and plasma membrane vesicles were used to characterize Na+ and HCO3- transport by rat hepatocytes. Na+ uptake into hepatocytes was stimulated approximately 10-fold by 25 mM extracellular HCO3-.HCO3--stimulated Na+ uptake was saturable, abolished by 4-acetamido-4'-isothiocyano-2,2'-disulfonic acid stilbene (SITS), and unaffected by amiloride or Cl- removal. Neither propionate nor acetate reproduced this effect of HCO3-. 22Na efflux from preloaded hepatocytes was similarly increased approximately 10-fold by an in greater than out HCO3- concentration gradient. 22Na efflux was also increased by valinomycin and an in greater than out K+ concentration gradient in the presence but not absence of HCO3-. Intracellular pH (pHi) measured with the pH-sensitive fluorochrome 2',7'-bis-(2-carboxyethyl)-5-(and 6-)carboxyfluorescein (BCECF) decreased at a rate of 0.227 (+/- 0.074 SEM) pH units/min when extracellular HCO3- concentration was lowered from 25 to 5 mM at constant PCO2. This intracellular acidification rate was decreased 50-60% in the absence of Na+ or presence of SITS, and was unaffected by amiloride or Cl- removal. Membrane hyperpolarization produced by valinomycin and an in greater than out K+ concentration gradient caused pHi to fall; the rate of fall was decreased 50-70% by Na+ removal or SITS, but not amiloride. An inside positive K+ diffusion potential and a simultaneous out greater than in HCO3- gradient produced a transient 4,4'-diisothiocyano-2,2' disulfonic acid stilbene (DIDS) sensitive, amiloride-insensitive 22Na accumulation in basolateral but not canalicular membrane vesicles. Rat hepatocytes thus exhibit electrogenic basolateral Na+/HCO3- cotransport.

  8. Phyla- and Subtype-Selectivity of CgNa, a Na+ Channel Toxin from the Venom of the Giant Caribbean Sea Anemone Condylactis Gigantea

    PubMed Central

    Billen, Bert; Debaveye, Sarah; Béress, Lászlo; Tytgat, Jan

    2010-01-01

    Because of their prominent role in electro-excitability, voltage-gated sodium (NaV) channels have become the foremost important target of animal toxins. These toxins have developed the ability to discriminate between closely related NaV subtypes, making them powerful tools to study NaV channel function and structure. CgNa is a 47-amino acid residue type I toxin isolated from the venom of the Giant Caribbean Sea Anemone Condylactis gigantea. Previous studies showed that this toxin slows the fast inactivation of tetrodotoxin-sensitive NaV currents in rat dorsal root ganglion neurons. To illuminate the underlying NaV subtype-selectivity pattern, we have assayed the effects of CgNa on a broad range of mammalian isoforms (NaV1.2–NaV1.8) expressed in Xenopus oocytes. This study demonstrates that CgNa selectively slows the fast inactivation of rNaV1.3/β1, mNaV1.6/β1 and, to a lesser extent, hNaV1.5/β1, while the other mammalian isoforms remain unaffected. Importantly, CgNa was also examined on the insect sodium channel DmNaV1/tipE, revealing a clear phyla-selectivity in the efficacious actions of the toxin. CgNa strongly inhibits the inactivation of the insect NaV channel, resulting in a dramatic increase in peak current amplitude and complete removal of fast and steady-state inactivation. Together with the previously determined solution structure, the subtype-selective effects revealed in this study make of CgNa an interesting pharmacological probe to investigate the functional role of specific NaV channel subtypes. Moreover, further structural studies could provide important information on the molecular mechanism of NaV channel inactivation. PMID:21833172

  9. Contributions of cellular leak pathways to net NaHCO3 and NaCl absorption.

    PubMed Central

    Preisig, P A; Alpern, R J

    1989-01-01

    Proton and formic acid permeabilities were measured in the in vivo microperfused rat proximal convoluted tubule by examining the effect on intracellular pH when [H] and/or [formic acid] were rapidly changed in the luminal or peritubular fluids. Apical and basolateral membrane H permeabilities were 0.52 +/- 0.07 and 0.67 +/- 0.18 cm/s, respectively. Using these permeabilities we calculate that proton backleak from the luminal fluid to cell does not contribute significantly to net proton secretion in the early proximal tubule, but may contribute in the late proximal tubule. Apical and basolateral membrane formic acid permeabilities measured at extracellular pH 6.62 were 4.6 +/- 0.5 X 10(-2) and 6.8 +/- 1.5 X 10(-2) cm/s, respectively. Control studies demonstrated that the formic acid permeabilities were not underestimated by either the simultaneous movement of formate into the cell or the efflux of formic acid across the opposite membrane. The measured apical membrane formic acid permeability is too small to support all of transcellular NaCl absorption in the rat by a mechanism that involves Na/H-Cl/formate transporters operating in parallel with formic acid nonionic diffusion. PMID:2542374

  10. Structure determination in 55-atom Li-Na and Na-K nanoalloys.

    PubMed

    Aguado, Andrés; López, José M

    2010-09-01

    The structure of 55-atom Li-Na and Na-K nanoalloys is determined through combined empirical potential (EP) and density functional theory (DFT) calculations. The potential energy surface generated by the EP model is extensively sampled by using the basin hopping technique, and a wide diversity of structural motifs is reoptimized at the DFT level. A composition comparison technique is applied at the DFT level in order to make a final refinement of the global minimum structures. For dilute concentrations of one of the alkali atoms, the structure of the pure metal cluster, namely, a perfect Mackay icosahedron, remains stable, with the minority component atoms entering the host cluster as substitutional impurities. At intermediate concentrations, the nanoalloys adopt instead a core-shell polyicosahedral (p-Ih) packing, where the element with smaller atomic size and larger cohesive energy segregates to the cluster core. The p-Ih structures show a marked prolate deformation, in agreement with the predictions of jelliumlike models. The electronic preference for a prolate cluster shape, which is frustrated in the 55-atom pure clusters due to the icosahedral geometrical shell closing, is therefore realized only in the 55-atom nanoalloys. An analysis of the electronic densities of states suggests that photoelectron spectroscopy would be a sufficiently sensitive technique to assess the structures of nanoalloys with fixed size and varying compositions.

  11. 23 Na and 17O NMR studies of hyperkagome Na4Ir3O8

    NASA Astrophysics Data System (ADS)

    Shockley, Abigail; Bert, Fabrice; Orain, Jean-Christophe; Okamoto, Yoshihiko; Mendels, Philippe

    2015-03-01

    Na4Ir3O8 is a unique case of a 3D corner sharing triangular lattice which can be decorated with quantum spins. It has spurred a lot of theoretical interest as a spin liquid candidate of a new kind where the Hamiltonian might not be thought in terms of a simple Heisenberg case because of spin orbit coupling on the Ir 5d element. We present a comprehensive set of NMR data taken on both the 23Na and 17O sites. We have found that magnetic freezing of all Ir sites sets in below Tf ~ 7.5K ~ 0 . 019 J with a clear hyperfine field transferred from Ir moments and a drastic decrease of 1 /T1 . Above Tf, physical properties are expected to be a landmark of frustration in this exotic geometry. We will discuss our shift and relaxation data in the temperature range of 300K to 7.5 K in the light of published thermodynamic measurements (Y. Okamotoa et al, PRL 99 137207, 2007 and Y. Singh et al, PRB 88 220413(R), 2013) and comment on their implications for the already existing large body of theoretical work.

  12. α-synuclein assemblies sequester neuronal α3-Na+/K+-ATPase and impair Na+ gradient

    PubMed Central

    Shrivastava, Amulya Nidhi; Redeker, Virginie; Fritz, Nicolas; Pieri, Laura; Almeida, Leandro G; Spolidoro, Maria; Liebmann, Thomas; Bousset, Luc; Renner, Marianne; Léna, Clément; Aperia, Anita; Melki, Ronald; Triller, Antoine

    2015-01-01

    Extracellular α-synuclein (α-syn) assemblies can be up-taken by neurons; however, their interaction with the plasma membrane and proteins has not been studied specifically. Here we demonstrate that α-syn assemblies form clusters within the plasma membrane of neurons. Using a proteomic-based approach, we identify the α3-subunit of Na+/K+-ATPase (NKA) as a cell surface partner of α-syn assemblies. The interaction strength depended on the state of α-syn, fibrils being the strongest, oligomers weak, and monomers none. Mutations within the neuron-specific α3-subunit are linked to rapid-onset dystonia Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC). We show that freely diffusing α3-NKA are trapped within α-syn clusters resulting in α3-NKA redistribution and formation of larger nanoclusters. This creates regions within the plasma membrane with reduced local densities of α3-NKA, thereby decreasing the efficiency of Na+ extrusion following stimulus. Thus, interactions of α3-NKA with extracellular α-syn assemblies reduce its pumping activity as its mutations in RDP/AHC. PMID:26323479

  13. Ecotoxicological evaluation of three deicers (NaCl, NaFo, CMA)-effect on terrestrial organisms.

    PubMed

    Robidoux, P Y; Delisle, C E

    2001-02-01

    The use of chemical deicers such as sodium chloride (NaCl) has increased significantly during the past three decades. Deicers induce metal corrosion and alter the physicochemical properties of soils and water. Environmental damage caused by the use of NaCl has prompted government agencies to find alternative deicers. This article presents a comparative ecotoxicological study of three deicers on soil organisms. Sodium formiate (NaFo) and calcium-magnesium acetate (CMA) are the most interesting commercially available deicers based upon their characteristics and potential toxicity. Organisms used in this study were four species of macrophytes (cress (Lepidium sativum), barley (Ordeum vulgare), red fescue grass (Festuca rubra), Kentucky bluegrass (Poa pratensis)) and an invertebrate (Eisenia fetida). Using standardized and modified methods, the relative toxicity of deicers was CMA < NaFo congruent with NaCl. The results demonstrate that these chemicals could have similar impacts in terrestrial environments since similar quantities of NaFo and greater amounts of CMA are necessary to achieve the same efficiency as NaCl. The toxicity of the tested substances was lower in natural composted soil than in artificial substrate (silica or OECD soil), indicating decreased environmental bioavailability. The response of the organisms changed according to endpoint, species, and soil characteristics (artificial substrate as compared to natural organic soil). The most sensitive endpoint measured was macrophyte growth with Kentucky bluegrass being the most sensitive species.

  14. Robust NaO2 Electrochemistry in Aprotic Na-O2 Batteries Employing Ethereal Electrolytes with a Protic Additive.

    PubMed

    Abate, Iwnetim I; Thompson, Leslie E; Kim, Ho-Cheol; Aetukuri, Nagaphani B

    2016-06-16

    Aprotic metal-oxygen batteries, such as Li-O2 and Na-O2 batteries, are of topical research interest as high specific energy alternatives to state-of-the-art Li-ion batteries. In particular, Na-O2 batteries with NaO2 as the discharge product offer higher practical specific energy with better rechargeability and round-trip energy efficiency when compared to Li-O2 batteries. In this work, we show that the electrochemical deposition and dissolution of NaO2 in Na-O2 batteries is unperturbed by trace water impurities in Na-O2 battery electrolytes, which is desirable for practical battery applications. We find no evidence for the formation of other discharge products such as Na2O2·H2O. Furthermore, the electrochemical efficiency during charge remains near ideal in the presence of trace water in electrolytes. Although sodium anodes react with trace water leading to the formation of a high-impedance solid electrolyte interphase, the increase in discharge overpotential is only ∼100 mV when compared to cells employing nominally anhydrous electrolytes. PMID:27214400

  15. Robust NaO2 Electrochemistry in Aprotic Na-O2 Batteries Employing Ethereal Electrolytes with a Protic Additive.

    PubMed

    Abate, Iwnetim I; Thompson, Leslie E; Kim, Ho-Cheol; Aetukuri, Nagaphani B

    2016-06-16

    Aprotic metal-oxygen batteries, such as Li-O2 and Na-O2 batteries, are of topical research interest as high specific energy alternatives to state-of-the-art Li-ion batteries. In particular, Na-O2 batteries with NaO2 as the discharge product offer higher practical specific energy with better rechargeability and round-trip energy efficiency when compared to Li-O2 batteries. In this work, we show that the electrochemical deposition and dissolution of NaO2 in Na-O2 batteries is unperturbed by trace water impurities in Na-O2 battery electrolytes, which is desirable for practical battery applications. We find no evidence for the formation of other discharge products such as Na2O2·H2O. Furthermore, the electrochemical efficiency during charge remains near ideal in the presence of trace water in electrolytes. Although sodium anodes react with trace water leading to the formation of a high-impedance solid electrolyte interphase, the increase in discharge overpotential is only ∼100 mV when compared to cells employing nominally anhydrous electrolytes.

  16. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    PubMed

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. PMID:26652350

  17. Determinants of substrate and cation transport in the human Na+/dicarboxylate cotransporter NaDC3.

    PubMed

    Schlessinger, Avner; Sun, Nina N; Colas, Claire; Pajor, Ana M

    2014-06-13

    Metabolic intermediates, such as succinate and citrate, regulate important processes ranging from energy metabolism to fatty acid synthesis. Cytosolic concentrations of these metabolites are controlled, in part, by members of the SLC13 gene family. The molecular mechanism underlying Na(+)-coupled di- and tricarboxylate transport by this family is understood poorly. The human Na(+)/dicarboxylate cotransporter NaDC3 (SLC13A3) is found in various tissues, including the kidney, liver, and brain. In addition to citric acid cycle intermediates such as α-ketoglutarate and succinate, NaDC3 transports other compounds into cells, including N-acetyl aspartate, mercaptosuccinate, and glutathione, in keeping with its dual roles in cell nutrition and detoxification. In this study, we construct a homology structural model of NaDC3 on the basis of the structure of the Vibrio cholerae homolog vcINDY. Our computations are followed by experimental testing of the predicted NaDC3 structure and mode of interaction with various substrates. The results of this study show that the substrate and cation binding domains of NaDC3 are composed of residues in the opposing hairpin loops and unwound portions of adjacent helices. Furthermore, these results provide a possible explanation for the differential substrate specificity among dicarboxylate transporters that underpin their diverse biological roles in metabolism and detoxification. The structural model of NaDC3 provides a framework for understanding substrate selectivity and the Na(+)-coupled anion transport mechanism by the human SLC13 family and other key solute carrier transporters.

  18. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    PubMed

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading.

  19. On the structure and chemical bonding of Si62- and Si62- in NaSi6- upon Na+ coordination

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry Yu.; Alexandrova, Anastassia N.; Boldyrev, Alexander I.; Cui, Li-Feng; Li, Xi; Wang, Lai-Sheng

    2006-03-01

    Photoelectron spectroscopy was combined with ab initio calculations to elucidate the structure and bonding in Si62- and NaSi6-. Well-resolved electronic transitions were observed in the photoelectron spectra of Si6- and NaSi6- at three photon energies (355, 266, and 193nm). The spectra of NaSi6- were observed to be similar to those of Si6- except that the electron binding energies of the former are lower, suggesting that the Si6 motif in NaSi6- is structurally and electronically similar to that in Si6-. The electron affinities of Si6 and NaSi6 were measured fairly accurately to be 2.23±0.03eV and 1.80±0.05eV, respectively. Global minimum structure searches for Si62- and NaSi6- were performed using gradient embedded genetic algorithm followed by B3LYP, MP2, and CCSD(T) calculations. Vertical electron detachment energies were calculated for the lowest Si6- and NaSi6- structures at the CCSD(T)/6-311+G(2df ), ROVGF/6-311+G(2df), UOVGF/6-311+G(2d), and time-dependent B3LYP/6-311+G(2df) levels of theory. Experimental vertical detachment energies were used to verify the global minimum structure for NaSi6-. Though the octahedral Si62-, analogous to the closo form of borane B6H62-, is the most stable form for the bare hexasilicon dianion, it is not the kernel for the NaSi6- global minimum. The most stable isomer of NaSi6- is based on a Si62- motif, which is distorted into C2v symmetry similar to the ground state structure of Si6-. The octahedral Si62- coordinated by a Na+ is a low-lying isomer and was also observed experimentally. The chemical bonding in Si62- and NaSi6- was understood using natural bond orbital, molecular orbital, and electron localization function analyses.

  20. Na double-edge magneto-optic filter for Na lidar profiling of wind and temperature in the lower atmosphere.

    PubMed

    Huang, Wentao; Chu, Xinzhao; Williams, B P; Harrell, S D; Wiig, Johannes; She, C-Y

    2009-01-15

    A Na double-edge magneto-optic filter is proposed for incorporation into the receiver of a three-frequency Na Doppler lidar to extend its wind and temperature measurements into the lower atmosphere. Two prototypes based on cold- and hot-cell designs were constructed and tested with laser scanning and quantum mechanics modeling. The hot-cell filter exhibits superior performances over the cold-cell filter containing buffer gas. Lidar simulations, metrics, and error analyses show that simultaneous wind and temperature measurements are feasible in the altitude range of 20-50 km using the hot-cell filter and reasonable Na lidar parameters. PMID:19148254

  1. Lattice sites of Na dopants in ZnO

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β ‑ particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm‑2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8–1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  2. Lattice sites of Na dopants in ZnO

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β - particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm-2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8-1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  3. Degradation Of Carbon/Phenolic Composites By NaOH

    NASA Technical Reports Server (NTRS)

    King, H. M.; Semmel, M. L.; Goldberg, B. E.; Clinton, Raymond G., Jr.

    1989-01-01

    Effects of sodium hydroxide contamination level on physical and chemical properties of phenolic resin and carbon/phenolic composites described in report. NaOH degrades both carbon and phenolic components of carbon/phenolic laminates.

  4. VIEW OF CEMETERY SECTION NA (NEW ADDITION), WITH NORTHERN PERIMETER ...

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

    VIEW OF CEMETERY SECTION NA (NEW ADDITION), WITH NORTHERN PERIMETER FENCE ALONG LINCOLN BOULEVARD IN FOREGROUND. VIEW TO SOUTH. - San Francisco National Cemetery, 1 Lincoln Boulevard, San Francisco, San Francisco County, CA

  5. VIEW OF CEMETERY SECTIONS NA (NEW ADDITION) AND NAWS (NEW ...

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

    VIEW OF CEMETERY SECTIONS NA (NEW ADDITION) AND NAWS (NEW ADDITION WEST SIDE) ALONG NORTH DRIVE, WITH MAINTENANCE COMPLEX AT LEFT BACKGROUND. VIEW TO SOUTHEAST. - San Francisco National Cemetery, 1 Lincoln Boulevard, San Francisco, San Francisco County, CA

  6. Interpretation of Na-K-Mg relations in geothermal waters

    USGS Publications Warehouse

    Fournier, R.O.

    1990-01-01

    When using a Na-K-???Mg triangular diagram as an aid in the interpretation of a geothermal water, the estimated temperature of last water-rock equilibration may change by as much as 50??C, depending on which of the many Na/K geothermometers one assumes is correct. A particular geothermometer may work well in one place and not in another because of differences in the mineralogy of the phases that are in contact with the reservoir fluid. The position of the full equilibrium line that is used for geothermometry and for assessing degrees of departure from equilibrium also changes as the assumed K/???Mg geothermometer equation changes. The degree of ambiguity can be evaluated by utilizing the results of all the recently published Na/K geothermometers on a single Na-K-???Mg triangular plot.

  7. Tb/Na tobermorite: Thermal behaviour and high temperature products

    SciTech Connect

    Garra, Walter; Marchetti, Fabio; Merlino, Stefano

    2009-06-15

    By heating a sample of Tb/Na tobermorite we obtained a phase which was identified through its X-ray diffraction (XRD) pattern, as terbium silicate apatite. Subsequently this compound has been directly prepared by solid state reaction and we carried out a structural refinement from XRD data in space group P6{sub 3}/m obtaining cell parameters a=9.39199(4) A and c=6.84041(5) A. Terbium silicate apatite heated in melted NaF led to Tb{sub 4}O{sub 7} crystals. - Graphical Abstract: By heating over 900 deg. C Tb/Na tobermorite a terbium silicate apatite was obtained. The same product has been independently prepared and structurally characterized from powder diffraction data. Attempts of crystallizing terbium silicate apatite from melted NaF led to Tb{sub 4}O{sub 7} crystals.

  8. The liquid krypton calorimeter of NA48: First operation results

    NASA Astrophysics Data System (ADS)

    Costantini, F.

    1998-02-01

    The first technical run of the complete NA48 experimental apparatus took place in 1996. The first operation results of the full size liquid Krypton electromagnetic calorimeter as energy resolution and π 0 mass resolution are presented in this paper.

  9. Regulation of Na v channels in sensory neurons.

    PubMed

    Chahine, Mohamed; Ziane, Rahima; Vijayaragavan, Kausalia; Okamura, Yasushi

    2005-10-01

    Voltage-gated Na(+) channels have an essential role in the biophysical properties of nociceptive neurons. Factors that regulate Na(+) channel function are of interest from both pathophysiological and therapeutic perspectives. Increasing evidence indicates that changes in expression or inappropriate modulation of these channels leads to electrical instability of the cell membrane and the inappropriate spontaneous activity that is observed following nerve injury, and that this might contribute to neuropathic pain. The role of Na(v) channels in nociception depends on modulation by factors such as auxiliary beta-subunits, cytoskeletal proteins and the phosphorylation state of neurons. In this review we describe the modulation of Na(v) channels on sensory neurons by auxiliary beta-subunits, protein kinases and cytoskeletal proteins.

  10. Na+ and Rb+ tracer diffusion in alkali halides

    NASA Astrophysics Data System (ADS)

    Beniere, F.; Sen, S. K.

    1991-11-01

    We have undertaken a fundamental study of heterodiffusion of foreign ions in pure single crystals. The present work describes the measurements of the diffusion coefficient of monovalent cations in some alkali halides, namely Na+ and Rb+ into KCl, KBr, NaI and KI. The priority is given to the super-accuracy of the experimental data. The target is to test the validity of the existing theories for calculating the enthalpy and entropy of migration.

  11. Na+ transport by rabbit urinary bladder, a tight epithelium.

    PubMed

    Lewis, S A; Diamond, J M

    1976-08-27

    By in vitro experiments on rabbit bladder, we reassessed the traditional view that mammalian urinary bladder lacks ion transport mechanisms. Since the ratio of actual-to-nominal membrane area in folded epithelia is variable and hard to estimate, we normalized membrane properties to apical membrane capacitance rather than to nominal area (probably 1 muF approximately 1 cm2 actual area). A new mounting technique that virtually eliminates edge damage yielded resistances up to 78,000 omega muF for rabbit bladder, and resistances for amphibian skin and bladder much higher than those usually reported. This technique made it possible to observe a transport-related conductance pathway, and a close correlation between transepithelial conductance (G) and short-circuit current (Isc) in these tight epithelia. G and Isc were increased by mucosal (Na+) [Isc approximately 0 when (Na+) approximately 0], aldosterone, serosal (HCO-3) and high mucosal (H+); were decreased by amiloride, mucosal (Ca++), ouabain, metabolic inhibitors and serosal (H+); and were unaffected by (Cl-) and little affected by antidiuretic hormone (ADH). Physiological variation in the rabbits' dietary Na+ intake caused variations in bladder G and Isc similar to those caused by the expected in vivo changes in aldosterone levels. The relation between G and Isc was the same whether defined by diet changes, natural variation among individual rabbits, or most of the above agents. A method was developed for separately resolving conductances of junctions, basolateral cell membrane, and apical cell membrane from this G--Isc relation. Net Na+ flux equalled Isc. Net Cl- flux was zero on short circuit and equalled only 25% of net Na+ flux in open circuit. Bladder membrane fragments contained a Na+-K+-activated, ouabain-inhibited ATPase. The physiological significance of Na+ absorption against steep gradients in rabbit bladder may be to maintain kidney-generated ion gradients during bladder storage of urine, especially

  12. An empirical NaKCa geothermometer for natural waters

    USGS Publications Warehouse

    Fournier, R.O.; Truesdell, A.H.

    1973-01-01

    An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340??C. The data for most geothermal waters cluster near a straight line when plotted as the function log ( Na K) + ?? log [ ??? (Ca) Na] vs reciprocal of absolute temperature, where ?? is either 1 3 or 4 3 depending upon whether the water equilibrated above or below 100??C. For most waters tested, the method gives better results than the Na K methods suggested by other workers. The ratio Na K should not be used to estimate temperature if ??? ( MCa) MNa is greater than 1. The Na K values of such waters generally yield calculated temperatures much higher than the actual temperature at which water interacted with the rock. A comparison of the composition of boiling hot-spring water with that obtained from a nearby well (170??C) in Yellowstone Park shows that continued water-rock reactions may occur during ascent of water even though that ascent is so rapid that little or no heat is lost to the country rock, i.e. the water cools adiabatically. As a result of such continued reaction, waters which dissolve additional Ca as they ascend from the aquifer to the surface will yield estimated aquifer temperatures that are too low. On the other hand, waters initially having enough Ca to deposit calcium carbonate during ascent may yield estimated aquifer temperatures that are too high if aqueous Na and K are prevented from further reaction with country rock owing to armoring by calcite or silica minerals. The Na-K-Ca geothermometer is of particular interest to those prospecting for geothermal energy. The method also may be of use in interpreting compositions of fluid inclusions. ?? 1973.

  13. Na sup + -glycine cotransport in canalicular liver plasma membrane vesicles

    SciTech Connect

    Moseley, R.H.; Ballatori, N.; Murphy, S.M. Yale Univ. School of Medicine, New Haven, CT Univ. of Rochester School of Medicine and Dentistry, NY )

    1988-08-01

    By use of purified rat canalicular liver plasma membrane (cLPM) vesicles, the present study determined the driving forces for glycine transport across this membrane domain. Initial rates of ({sup 3}H)glycine uptake in cLPM vesicles were stimulated by an inwardly directed Na{sup +} gradient but not by a K{sup +} gradient. Na{sup +} gradient-dependent uptake of glycine demonstrated cation specificity for Na{sup +}, dependence on extravesicular Cl{sup {minus}}, stimulation by an intravesicular-negative membrane potential, and inhibition by dissipation of the Na{sup +} gradient with gramicidin D. Na{sup +} gradient-dependent glycine cotransport also demonstrated greater sensitivity to inhibition by sarcosine than 2-(methylamino)-isobutyric acid. Accelerated exchange diffusion of ({sup 3}H)glycine was demonstrated in the presence of Na{sup +} when cLPM vesicles were preloaded with glycine but not with L-alanine or L-proline. Substrate velocity analysis of net Na{sup +}-dependent ({sup 3}H)glycine uptake over the range of amino acid concentrations from 5 {mu}M to 5 mM demonstrated two saturable transport systems, one of high capacity and low affinity and one of low capacity and comparatively high affinity. These results indicate that, in addition to previously described neutral and anionic amino acid transport systems, Na{sup +} gradient-dependent glycine transport mechanisms are present on the canalicular domain of the liver plasma membrane. These canalicular reabsorptive mechanisms may serve to reclaim some of the glycine generated within the canalicular lumen from the intrabiliary hydrolysis of glutathione.

  14. High performance MCFC using Li/Na electrolyte

    SciTech Connect

    Donado, R.A.; Ong, E.T.; Sishtla, C.I.

    1995-08-01

    The substitution of a lithium/ sodium carbonate (Li/Na) mixture for the lithium/potassium carbonate (Li/K) electrolyte used in MCFCs holds the promise of higher ionic conductivity, higher exchange current density at both electrodes, lower vapor pressure, and lower cathode dissolution rates. However, when the substitution is made in cells optimized for use with the Li/K electrolyte, the promised increase in performance is not realized. As a consequence the literature contains conflicting data with regard to the performance, compositional stability, and chemical reactivity of the Li/Na electrolyte. Experiments conducted at the Institute of Gas Technology (IGT) concluded that the source of the problem is the different wetting characteristics of the two electrolytes. Electrode pore structures optimized for use with Li/K do not work well with Li/Na. Using proprietary methods and materials, IGT was able to optimize a set of electrodes for the Li/Na electrolyte. Experiments conducted in bench-scale cells have confirmed the superior performance of the Li/Na electrolyte compared to the Li/K electrolyte. The Li/Na cells exhibited a 5 to 8 percent improvement in overall performance, a substantial decrease in the rate of cathode dissolution, and a decreased decay rate. The longest running cell has logged over 13,000 hours of operation with a decay rate of less than 2 mV/1000 hours.

  15. Deliquescence of NaCl–NaNO3, KNO3–NaNO3, and NaCl–KNO3 salt mixtures from 90 to 120°C

    PubMed Central

    Carroll, Susan; Craig, Laura; Wolery, Thomas J

    2005-01-01

    We conducted reversed deliquescence experiments in saturated NaCl–NaNO3–H2O, KNO3–NaNO3–H2O, and NaCl–KNO3–H2O systems from 90 to 120°C as a function of relative humidity and solution composition. NaCl, NaNO3, and KNO3 represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV. Discrepancy between model prediction and experiment can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25°C models for Cl–NO3 and K–NO3 ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the nonideal behavior of these highly concentrated solutions.

  16. 23Na and 1H NMR Microimaging of Intact Plants

    NASA Astrophysics Data System (ADS)

    Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

    2000-06-01

    23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  17. thin films grown with additional NaF layers

    NASA Astrophysics Data System (ADS)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  18. Endogenous ouabain in renal Na(+) handling and related diseases.

    PubMed

    Manunta, Paolo; Messaggio, Elisabetta; Casamassima, Nunzia; Gatti, Guido; Carpini, Simona Delli; Zagato, Laura; Hamlyn, John M

    2010-12-01

    The Na(+) pump and its Endogenous modulator Ouabain (EO) can be considered as an ancestral enzymatic system, conserved among species ranging from Drosophila to humans, related to Na handling. In this review, we examine how EO is linked with vascular function in hypertension and if it impacts the pathogenesis of heart and renal failure. Moreover, the molecular mechanism of endogenous ouabain-linked hypertension involves the sodium pump/sodium-calcium exchanger duet. Biosynthesis of EO occurs in adrenal glands and is under the control of angiotensin II, ACTH and epinephrine. Elevated concentrations of EO and in the sub-nanomolar concentration range were found to stimulate proliferation and differentiation of cardiac and smooth muscle cells. They may have a primary role in the development of cardiac dysfunction and failure. Experimental data suggest that the Na/K-ATPase α(2)-catalytic subunit causes EO-induced vasoconstriction. Finally, maneuvers that promote Na depletion, as diuretic therapy or reduced Na intake, raise the EO levels. Taken together, these findings suggest a key role for EO in body Na homeostasis.

  19. Diffusive transport through compacted Na- and Ca-bentonite

    NASA Astrophysics Data System (ADS)

    Choi, J.-W.; Oscarson, D. W.

    1996-04-01

    The effect of exchangeable cation — Na + and Ca 2+ — on the diffusive transport of I -, Sr 2+ and 3H (as HTO) in compacted bentonite was examined using a through-diffusion method. Total intrinsic diffusion coefficients, Di, were determined from the steady-state flux of the diffusants through the clays, and apparent diffusion coefficients, Da, were obtained from the time lag technique. The clays were compacted to a dry bulk density of 1.3 Mg/m 3, and Na-bentonite was saturated with a solution of 100 mol NaCl/m3 and Ca-bentonite with one of 50 mol CaCl 2/m 3. The Di values for all diffusants are 2 to 6 times higher in the Ca- than Na-clay. We attribute this to the larger quasicrystal, or particle, size of Ca- compared to Na-bentonite. Hence, Ca-bentonite has a greater proportion of relatively large pores; this was confirmed by Hg intrusion porosimetry. This means the diffusion pathways in Ca-bentonite are less tortuous than those in Na-bentonite. Moreover, in some cases the effective porosity, or the porosity available for diffusive transport, may be greater in Ca-bentonite. The D a values are inversely proportional to the distribution coefficients of the diffusants with the clays.

  20. Cardiac Na currents and the inactivating, reopening, and waiting properties of single cardiac Na channels

    PubMed Central

    1985-01-01

    Tetrodotoxin (TTX)-sensitive Na currents were examined in single dissociated ventricular myocytes from neonatal rats. Single channel and whole cell currents were measured using the patch-clamp method. The channel density was calculated as 2/micron 2, which agreed with our usual finding of four channels per membrane patch. At 20 degrees C, the single channel conductance was 20 pS. The open time distributions were fit by a single-exponential function with a mean open time of approximately 1.0 ms at membrane potentials from -60 to -40 mV. Averaged single channel and whole cell currents were similar when scaled and showed both fast and slow rates of inactivation. The inactivation and activation gating shifted quickly to hyperpolarized potentials for channels in cell-attached as well as excised patches, whereas a much slower shift occurred in whole cells. Slowly inactivating currents were present in both whole cell and single channel current measurements at potentials as positive as -40 mV. In whole cell measurements, the potential range could be extended, and slow inactivation was present at potentials as positive as -10 mV. The curves relating steady state activation and inactivation to membrane potential had very little overlap, and slow inactivation occurred at potentials that were positive to the overlap. Slow inactivation is in this way distinguishable from the overlap or window current, and the slowly inactivating current may contribute to the plateau of the rat cardiac action potential. On rare occasions, a second set of Na channels having a smaller unit conductance and briefer duration was observed. However, a separate set of threshold channels, as described by Gilly and Armstrong (1984. Nature [Lond.]. 309:448), was not found. For the commonly observed Na channels, the number of openings in some samples far exceeded the number of channels per patch and the latencies to first opening or waiting times were not sufficiently dispersed to account for the slowly

  1. Regulation of the paracellular Na+ and Cl- conductances by the NaCl-generated osmotic gradient in a manner dependent on the direction of osmotic gradients.

    PubMed

    Tokuda, Shinsaku; Niisato, Naomi; Nakajima, Ken-Ichi; Marunaka, Yoshinori

    2008-02-01

    In the present study, we investigated the effect of osmolality on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)). An osmotic gradient generated by NaCl with relatively apical hypertonicity (NaCl-absorption-direction) induced a large increase in the G(Na) associated with a small increase in the G(Cl), whereas an osmotic gradient generated by NaCl with relatively basolateral hypertonicity (NaCl-secretion-direction) induced small increases in the G(Na) and the G(Cl). These increases in the Gp caused by NaCl-generated osmotic gradients were diminished by the application of sucrose canceling the NaCl-generated osmotic gradient. The osmotic gradient generated by apical [corrected] application of sucrose without any NaCl gradients had little effects on the Gp. However, this apical [corrected] application of sucrose produced a precondition drastically quickening the time course of the action of the NaCl-generated osmotic gradient on the Gp. Further, we found that application of the basolateral hypotonicity generated by reduction of NaCl concentration shifted the localization of claudin-1 to the apical from the lateral [corrected] side. These results indicate that the osmotic gradient regulates the paracellular ion conductive pathway of tight junctions via a mechanism dependent on the direction of NaCl gradients associated with a shift of claudin-1 localization to the apical side in renal A6 epithelial cells. PMID:18068115

  2. Na ordering and Co magnetism in a metallic antiferromagnet Na0.825CoO2

    NASA Astrophysics Data System (ADS)

    Young, Ben-Li; Chu, P.-Y.; Juang, J. Y.; Shu, G. J.; Chou, F. C.

    2014-03-01

    Sodium cobaltate, NaxCoO2, originally known as a battery material, has shown other prominent features such as thermoelectricity, magnetism, and superconductivity. For certain Na contents, the Na vacancies are not randomly distributed so that a superlattice structure is formed. We investigated the Na ordering and the Co magnetism in the x = 0.825 phase of a metallic antiferromagnet, by nuclear magnetic-resonance (NMR) techniques. We successfully derived the three-dimensional superstructure of the Na ordering, and found additional magnetic susceptibility component emerging at 60 K. In addition, a magnetic field-induced glassy behavior near a metamagnetic transition was discovered. This work was supported by NSC Grants No. 98-2112-M-009-016-MY3 and No. 101-2112-M-009-015-MY2 and by the MOE ATU Program operated at NCTU.

  3. Simultaneous optical excitation of Na electronic and CF{sub 4} vibrational modes in Na+CF{sub 4} collisions

    SciTech Connect

    Alekseev, V. A.; Grosser, J.; Hoffmann, O.; Rebentrost, F.

    2008-11-28

    We report on the ultraviolet excitation of Na(3s)+CF{sub 4} collision pairs in a crossed molecular beam experiment. We observe Na(3d) collision products originating from the process Na(3s)+CF{sub 4}({nu}{sub 3}=0)+h{nu}{yields}Na(3d)+CF{sub 4}({nu}{sub 3}=1). The spectral intensity distribution of the collision products and the prevailing small angle scattering confirm a previously proposed long range dipole-dipole mechanism. We report velocity-resolved spectra and a comparison to preliminary numerical results based on collisional broadening theory. Polarization experiments suggest future potential for the observation of collision geometries.

  4. NaNaX 4--4th event of the international conference series "Nanoscience with Nanocrystals".

    PubMed

    Reiss, Peter

    2010-07-27

    The conference "NaNaX 4--Nanoscience with Nanocrystals" held near Munich (April 11-15, 2010) brought together a wide range of scientists discussing the most important current issues in the field of colloidal nanoparticles. Chemical synthesis gives access to nanocrystals of controlled size, shape, composition, and surface functionalization. Past research mainly concentrated on cadmium and lead chalcogenide nanocrystals as well as on gold and iron oxide nanoparticles. Today, there is a trend toward the development of nanoscale heterostructures, which combine different classes of materials and exhibit unique optical, magnetic, and electronic properties. Beside their interest for fundamental science, colloidal nanoparticles hold great promise for a wide range of applications. To this end, speakers and poster presenters showed routes for designing and using nanocrystals in biological imaging and sensing, in energy-related applications, and in catalysis. This report gives a nonexhaustive overview of selected "hot topics" in nanoparticle research discussed at NaNaX 4.

  5. Crystallization kinetics from mixture Na2SO4/glycerol droplets of Na2SO4 by FTIR-ATR

    NASA Astrophysics Data System (ADS)

    Tan, Dan-Ting; Cai, Chen; Zhang, Yun; Wang, Na; Pang, Shu-Feng; Zhang, Yun-Hong

    2016-08-01

    The efflorescence of mixed Na2SO4/glycerol aerosols on the ZnSe substrate with various mole ratios (Na2SO4/glycerol = 1:1, 1:2, 1:4) has been studied in the relative humidity (RH) linearly decline process, using a situ Fourier transform infrared attenuated total reflection (FTIR-ATR) technique. The crystal ratio at a given RH can be gained by the absorbance of the band at 1132 cm-1, which shows the incomplete nucleation for mixed Na2SO4/glycerol aerosols and the decreased amount of the droplets crystallized at the lowest RH with the glycerol increase. Using the volume fraction of droplets that have yet to crystallize, the heterogeneous nucleation kinetics has been gained. By the Extended Aerosol Inorganics Model (E-AIM), the nucleation rate as the function of solute saturation degree has been gained for various mixed Na2SO4/glycerol aerosols.

  6. The tetrodotoxin-resistant Na+ channel Na (v)1.8 reduces the potency of local anesthetics in blocking C-fiber nociceptors.

    PubMed

    Kistner, Katrin; Zimmermann, Katharina; Ehnert, Corina; Reeh, Peter W; Leffler, Andreas

    2010-04-01

    The generation of action potentials in nociceptive neurons is accomplished by the tetrodotoxin-resistant (TTXr) Na+ channel Na(v)1.8. Following nerve injury, a redistribution of Na(v)1.8 from dorsal root ganglion (DRG) neurons into peripheral axons contributes to hyperexcitability and possibly to neuropathic pain. Na(v)1.8 has been reported to display a lower sensitivity to block by Na+ channel blockers as compared to TTX-sensitive (TTXs) Na(v) subunits. Furthermore, the antinociceptive efficacy of lidocaine is increased in Na(v)1.8-knockout mice. Here, we asked if Na(v)1.8 expression can reduce the susceptibility of sensory neurons to block by lidocaine. Employing wild-type and Na(v)1.8-knockout mice, we examined C-fibers in the skin-nerve preparation and Na+ currents in DRG neurons by patch-clamp recordings. Deletion of Na(v)1.8 resulted in an enhanced tonic block of Na+ currents in DRG neurons held at -80 mV but not at -140 mV. Accordingly, lower concentrations of lidocaine were required for a conduction block of C-fibers from Na(v)1.8-knockout as compared to wild-type mice. The efficacy of lidocaine on neurons lacking Na(v)1.8 was further increased by cold temperatures, due to a synergistic hyperpolarizing shift of the slow inactivation of TTXs Na+ channels by lidocaine and cooling. Finally, the approximately 90% reduction of TTXr Na+ currents in injured neurons from mice with a peripheral nerve injury was accompanied with an enhanced tonic block by lidocaine. In conclusion, our data demonstrate that the expression of Na(v)1.8 in sensory neurons can confine the antinociceptive efficacy of lidocaine and other Na+ channel blockers employed for pain treatment. PMID:20174994

  7. Probabilistic Models to Predict Listeria monocytogenes Growth at Low Concentrations of NaNO2 and NaCl in Frankfurters

    PubMed Central

    Gwak, Eunji; Oh, Mi-Hwa; Park, Beom-Young; Lee, Heeyoung; Lee, Soomin; Ha, Jimyeong; Lee, Jeeyeon; Kim, Sejeong; Choi, Kyoung-Hee; Yoon, Yohan

    2015-01-01

    This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO2 and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO2 (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15℃ for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO2 and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO2 and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO2 on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10℃. A single application of NaNO2 or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15℃, but the combination of NaNO2 or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO2 and NaCl, and the antilisterial effect of NaNO2 increased by NaCl under anaerobic condition. PMID:26877642

  8. Na(+)-translocating cytochrome bo terminal oxidase from Vitreoscilla: some parameters of its Na+ pumping and orientation in synthetic vesicles.

    PubMed

    Park, C; Moon, J Y; Cokic, P; Webster, D A

    1996-09-10

    Vitreoscilla cytochrome bo ubiquinol oxidase is similar in some properties to the Escherichia coli enzyme, but unlike the latter, the Vitreoscilla oxidase functions as a primary Na+ pump. When purified Vitreoscilla cytochrome bo is incorporated into liposomes made from Vitreoscilla phospholipids and energized with a quinol substrate, it translocates Na+, not H+, across the vesicle membrane. Since protonophores CCCP (carbonyl cyanide m-chlorophenylhydrazone) and DTHB (3,5-di-tert-butyl-4-hydroxybenzaldehyde) stimulated the Na+ pumping, it is unlikely that it is a secondary effect due to the presence of Na+/H+ antiporter activity in the preparations. The efficiency of the Na+ pumping was 3.93 Na+ pumped per O2 consumed when ascorbate/TMPD was used as the substrate. The cytochrome has a K(m) and Kcat for Na+ of 2.9 mM and 277 s-1, respectively. When ferricytochrome c was entrapped within liposomes prepared from Vitreoscilla phospholipids, it was reduced by Q1H2 (ubiquinol-1) but not by ascorbate/TMPD (N,N,N',N'-tetramethyl-1,4-phenylenediamine). Although Q1H2 was oxidized by cytochrome bo in solution at a rate approximately 14 times that of the latter substrate, the rate of accumulation of Na+ within cytochrome bo vesicles driven by the membrane impermeable ascorbate/TMPD was 1.23 times that of the membrane permeable ubiquinol. These data allowed a calculation that in these synthetic proteoliposomes the cytochrome bo molecules are only 51% directed inward; a value of 61% inward-directed was estimated by measuring the ascorbate/TMPD oxidase activity of the proteoliposomes before and after disrupting them with Triton X-100. A random orientation of the E. coli cytochrome bo oxidase in proteoliposomes has also been reported. PMID:8794772

  9. Targeting Voltage Gated Sodium Channels NaV1.7, NaV1.8, and NaV1.9 for Treatment of Pathological Cough

    PubMed Central

    Muroi, Yukiko

    2015-01-01

    Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1–NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough. PMID:24272479

  10. Experimental and first-principles study of photoluminescent and optical properties of Na-doped CuAlO2: the role of the NaAl-2Na i complex

    NASA Astrophysics Data System (ADS)

    Liu, Ruijian; Li, Yongfeng; Yao, Bin; Ding, Zhanhui; Deng, Rui; Zhang, Ligong; Zhao, Haifeng; Liu, Lei

    2015-08-01

    We report that a band-tail emission at 3.08 eV, lower than near-band-edge energy, is observed in photoluminescence measurements of bulk Na-doped CuAlO2. The band-tail emission is attributed to Na-related defects. Electronic structure calculations based on the first-principles method demonstrate that the donor-acceptor compensated complex of NaAl-2Na i in Na-doped CuAlO2 plays a key role in leading to the band-tail emission and bandgap narrowing. Furthermore, Hall effect measurements indicates that the hole concentration in CuAlO2 is independent on Na doping, which is well understood by the donor-acceptor compensation effect of NaAl-2Na i complex.

  11. Na(+) -Activated K(+) Channels in Rat Supraoptic Neurones.

    PubMed

    Bansal, V; Fisher, T E

    2016-06-01

    The magnocellular neurosecretory cells (MNCs) of the hypothalamus secrete the neurohormones vasopressin and oxytocin. The systemic release of these hormones depends on the rate and pattern of MNC firing and it is therefore important to identify the ion channels that contribute to the electrical behaviour of MNCs. In the present study, we report evidence for the presence of Na(+) -activated K(+) (KN a ) channels in rat MNCs. KN a channels mediate outwardly rectifying K(+) currents activated by the increases in intracellular Na(+) that occur during electrical activity. Although the molecular identity of native KN a channels is unclear, their biophysical properties are consistent with those of expressed Slick (slo 2.1) and Slack (slo 2.2) proteins. Using immunocytochemistry and Western blot experiments, we found that both Slick and Slack proteins are expressed in rat MNCs. Using whole cell voltage clamp techniques on acutely isolated rat MNCs, we found that inhibiting Na(+) influx by the addition of the Na(+) channel blocker tetrodotoxin or the replacement of Na(+) in the external solution with Li(+) caused a significant decrease in sustained outward currents. Furthermore, the evoked outward current density was significantly higher in rat MNCs using patch pipettes containing 60 mm Na(+) than it was when patch pipettes containing 0 mm Na(+) were used. Our data show that functional KN a channels are expressed in rat MNCs. These channels could contribute to the activity-dependent afterhyperpolarisations that have been identified in the MNCs and thereby play a role in the regulation of their electrical behaviour. PMID:27091544

  12. NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

    PubMed Central

    Cope, Freeman W.

    1967-01-01

    The nuclear magnetic resonance (NMR) spectrum of Na+ is suitable for qualitative and quantitative analysis of Na+ in tissues. The width of the NMR spectrum is dependent upon the environment surrounding the individual Na+ ion. NMR spectra of fresh muscle compared with spectra of the same samples after ashing show that approximately 70% of total muscle Na+ gives no detectable NMR spectrum. This is probably due to complexation of Na+ with macromolecules, which causes the NMR spectrum to be broadened beyond detection. A similar effect has been observed when Na+ interacts with ion exchange resin. NMR also indicates that about 60% of Na+ of kidney and brain is complexed. Destruction of cell structure of muscle by homogenization little alters the per cent complexing of Na+. NMR studies show that Na+ is complexed by actomyosin, which may be the molecular site of complexation of some Na+ in muscle. The same studies indicate that the solubility of Na+ in the interstitial water of actomyosin gel is markedly reduced compared with its solubility in liquid water, which suggests that the water in the gel is organized into an icelike state by the nearby actomyosin molecules. If a major fraction of intracellular Na+ exists in a complexed state, then major revisions in most theoretical treatments of equilibria, diffusion, and transport of cellular Na+ become appropriate. PMID:6033590

  13. Thyroid thermogenesis. Relationships between Na+-dependent respiration and Na+ + K+-adenosine triphosphatase activity in rat skeletal muscle.

    PubMed Central

    Asano, Y; Liberman, U A; Edelman, I S

    1976-01-01

    The effect of thyroid status on QO2, QO2 (t) and NaK-ATPase activity was examined in rat skeletal muscle. QO2(t) (i.e. Na+-transport-dependent respiration) was estimated with ouabain or Na+-free media supplemented with K+. In contrast to the effects of ouabain on ion composition, intracellular K+ was maintained at about 125 meq/liter, and intracellular Na+ was almost nil in the Na+-free media. The estimates of QO2(t) were independent of the considerable differences in tissue ion concentrations. The increase in QO2(t) account for 47% of the increase in QO2 in the transition from the hypothyroid to the euthyroid state and 84% of the increase in the transition from the euthyroid to the hyperthyroid state. Surgical thyroidectomy lowered NaK-ATPase activity of the microsomal fraction (expressed per milligram protein) 32%; injections of triodothyronine (T3) increased this activity 75% in initially hypothyroid rats and 26% in initially euthyroid rats. Thyroidectomy was attended by significant falls in serum Ca and Pi concentrations. Administration of T3 resulted in further declines in serum Ca and marked increases in serum Ps concentrations. Similar effects were seen in 131I-treated rats, but the magnitude of the declines in serum Ca were less. The effects of T3 on QO2, QO2(t), and NaK-ATPase activity of skeletal muscle were indistinguishable in the 131I-ablated and surgically thyroidectomized rats. In thyroidectomized or euthyroid rats given repeated doses of T3, QO2(t) and NaA-ATPase activity increased proportionately. In thyroidectomized rats injected with single doses of T3, either 10, 50, or 250 mug/100 g body wt, QO2(t) increased linearly with NaK-ATPase activity. The kinetics of the NaK-ATPase activity was assessed with an ATP-generating system. T3 elicited a significant increase in Vmax with no change in Km for ATP. PMID:130385

  14. 75 FR 38874 - Proposed Collection; Comment Request for Form 706-NA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-06

    ... Internal Revenue Service Proposed Collection; Comment Request for Form 706-NA AGENCY: Internal Revenue...(c)(2)(A)). Currently, the IRS is soliciting comments concerning Form 706-NA, United States Estate...-0531. Form Number: 706-NA. Abstract: Form 706-NA is used to compute estate and generation-...

  15. C-peptide, Na+,K+-ATPase, and Diabetes

    PubMed Central

    Coste, T. C.; Jannot, M. F.; Raccah, D.; Tsimaratos, M.

    2004-01-01

    Na+,K+-ATPase is an ubiquitous membrane enzyme that allows the extrusion of three sodium ions from the cell and two potassium ions from the extracellular fluid. Its activity is decreased in many tissues of streptozotocin-induced diabetic animals. This impairment could be at least partly responsible for the development of diabetic complications. Na+,K+-ATPase activity is decreased in the red blood cell membranes of type 1 diabetic individuals, irrespective of the degree of diabetic control. It is less impaired or even normal in those of type 2 diabetic patients. The authors have shown that in the red blood cells of type 2 diabetic patients, Na+,K+-ATPase activity was strongly related to blood C-peptide levels in non–insulin-treated patients (in whom C-peptide concentration reflects that of insulin) as well as in insulin-treated patients. Furthermore, a gene-environment relationship has been observed. The alpha-1 isoform of the enzyme predominant in red blood cells and nerve tissue is encoded by the ATP1A1 gene.Apolymorphism in the intron 1 of this gene is associated with lower enzyme activity in patients with C-peptide deficiency either with type 1 or type 2 diabetes, but not in normal individuals. There are several lines of evidence for a low C-peptide level being responsible for low Na+,K+-ATPase activity in the red blood cells. Short-term C-peptide infusion to type 1 diabetic patients restores normal Na+,K+-ATPase activity. Islet transplantation, which restores endogenous C-peptide secretion, enhances Na+,K+-ATPase activity proportionally to the rise in C-peptide. This C-peptide effect is not indirect. In fact, incubation of diabetic red blood cells with C-peptide at physiological concentration leads to an increase of Na+,K+-ATPase activity. In isolated proximal tubules of rats or in the medullary thick ascending limb of the kidney, C-peptide stimulates in a dose-dependent manner Na+,K+-ATPase activity. This impairment in Na+,K+-ATPase activity, mainly

  16. Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption

    PubMed Central

    Welch, William J

    2015-01-01

    Adenosine type 1 receptor (A1-AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1-ARs in the proximal tubule, which is responsible for 60–70% of the reabsorption of filtered Na+ and fluid. Intratubular application of receptor antagonists indicates that A1-AR mediates a portion of Na+ uptake in PT and PT cells, via multiple transport systems, including Na+/H+ exchanger-3 (NHE3), Na+/PO4− co-transporter and Na+-dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1-AR antagonists and is lower in A1-AR KO mice., compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1-AR KO mice, compared to WT mice. Inhibition of A1-ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

  17. Links between hydrothermal environments, pyrophosphate, na(+), and early evolution.

    PubMed

    Holm, Nils G; Baltscheffsky, Herrick

    2011-10-01

    The discovery that photosynthetic bacterial membrane-bound inorganic pyrophosphatase (PPase) catalyzed light-induced phosphorylation of orthophosphate (Pi) to pyrophosphate (PPi) and the capability of PPi to drive energy requiring dark reactions supported PPi as a possible early alternative to ATP. Like the proton-pumping ATPase, the corresponding membrane-bound PPase also is a H(+)-pump, and like the Na(+)-pumping ATPase, it can be a Na(+)-pump, both in archaeal and bacterial membranes. We suggest that PPi and Na(+) transport preceded ATP and H(+) transport in association with geochemistry of the Earth at the time of the origin and early evolution of life. Life may have started in connection with early plate tectonic processes coupled to alkaline hydrothermal activity. A hydrothermal environment in which Na(+) is abundant exists in sediment-starved subduction zones, like the Mariana forearc in the W Pacific Ocean. It is considered to mimic the Archean Earth. The forearc pore fluids have a pH up to 12.6, a Na(+)-concentration of 0.7 mol/kg seawater. PPi could have been formed during early subduction of oceanic lithosphere by dehydration of protonated orthophosphates. A key to PPi formation in these geological environments is a low local activity of water.

  18. Estragole blocks neuronal excitability by direct inhibition of Na+ channels

    PubMed Central

    Silva-Alves, K.S.; Ferreira-da-Silva, F.W.; Peixoto-Neves, D.; Viana-Cardoso, K.V.; Moreira-Júnior, L.; Oquendo, M.B.; Oliveira-Abreu, K.; Albuquerque, A.A.C.; Coelho-de-Souza, A.N.; Leal-Cardoso, J.H.

    2013-01-01

    Estragole is a volatile terpenoid, which occurs naturally as a constituent of the essential oils of many plants. It has several pharmacological and biological activities. The objective of the present study was to investigate the mechanism of action of estragole on neuronal excitability. Intact and dissociated dorsal root ganglion neurons of rats were used to record action potential and Na+ currents with intracellular and patch-clamp techniques, respectively. Estragole blocked the generation of action potentials in cells with or without inflexions on their descendant (repolarization) phase (Ninf and N0 neurons, respectively) in a concentration-dependent manner. The resting potentials and input resistances of Ninf and N0 cells were not altered by estragole (2, 4, and 6 mM). Estragole also inhibited total Na+ current and tetrodotoxin-resistant Na+ current in a concentration-dependent manner (IC50 of 3.2 and 3.6 mM, respectively). Kinetic analysis of Na+ current in the presence of 4 mM estragole showed a statistically significant reduction of fast and slow inactivation time constants, indicating an acceleration of the inactivation process. These data demonstrate that estragole blocks neuronal excitability by direct inhibition of Na+ channel conductance activation. This action of estragole is likely to be relevant to the understanding of the mechanisms of several pharmacological effects of this substance. PMID:24345915

  19. Magnetism in Na-filled Fe-based skutterudites.

    PubMed

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.

  20. Associated proteins and renal epithelial Na+ channel function.

    PubMed

    Ismailov, I I; Berdiev, B K; Bradford, A L; Awayda, M S; Fuller, C M; Benos, D J

    1996-01-01

    The hypothesis that amiloride-sensitive Na+ channel complexes immunopurified from bovine renal papillary collecting tubules contain, as their core conduction component, an ENaC subunit, was tested by functional and immunological criteria. Disulfide bond reduction with dithiothreitol (DTT) of renal Na+ channels incorporated into planar lipid bilayers caused a reduction of single channel conductance from 40 pS to 13 pS, and uncoupled PKA regulation of this channel. The cation permeability sequence, as assessed from bi-ionic reversal potential measurements, and apparent amiloride equilibrium dissociation constant (K(amil)i) of the Na+ channels were unaltered by DTT treatment. Like ENaC, the DTT treated renal channel became mechanosensitive, and displayed a substantial decrease in K(amil)i following stretch (0.44 +/- 0.12 microM versus 6.9 +/- 1.0 microM). Moreover, stretch activation induced a loss in the channel's ability to discriminate between monovalent cations, and even allowed Ca2+ to permeate. Polyclonal antibodies generated against a fusion protein of alpha bENaC recognized a 70 kDa polypeptide component of the renal Na+ channel complex. These data suggest that ENaC is present in the immunopurified renal Na+ channel protein complex, and that PKA sensitivity is conferred by other associated proteins. PMID:8834119

  1. Kinetic comparisons of heart and kidney Na+,K(+)-ATPases.

    PubMed

    Garcia, Alvaro; Rasmussen, Helge H; Apell, Hans-Jürgen; Clarke, Ronald J

    2012-08-22

    Most kinetic measurements of the partial reactions of Na(+),K(+)-ATPase have been conducted on enzyme from mammalian kidney. Here we present a kinetic model that is based on the available equilibrium and kinetic parameters of purified kidney enzyme, and allows predictions of its steady-state turnover and pump current in intact cells as a function of ion and ATP concentrations and the membrane voltage. Using this model, we calculated the expected dependence of the pump current on voltage and extracellular Na(+) concentration. The simulations indicate a lower voltage dependence at negative potentials of the kidney enzyme in comparison with heart muscle Na(+),K(+)-ATPase, in agreement with experimental results. The voltage dependence is enhanced at high extracellular Na(+) concentrations. This effect can be explained by a voltage-dependent depopulation of extracellular K(+) ion binding sites on the E2P state and an increase in the proportion of enzyme in the E1P(Na(+))(3) state in the steady state. This causes a decrease in the effective rate constant for occlusion of K(+) by the E2P state and hence a drop in turnover. Around a membrane potential of zero, negligible voltage dependence is observed because the voltage-independent E2(K(+))(2) → E1 + 2K(+) transition is the major rate-determining step. PMID:22947929

  2. Magnetism in Na-filled Fe-based skutterudites

    SciTech Connect

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. We investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.

  3. Magnetism in Na-filled Fe-based skutterudites

    DOE PAGES

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. We investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material nearmore » an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.« less

  4. High-Pressure Polymorph of NaBiO3.

    PubMed

    Naa, Octavianti; Kumada, Nobuhiro; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Kusano, Yoshihiro; Oka, Kengo

    2016-06-20

    A new high-pressure polymorph of NaBiO3 (hereafter β-NaBiO3) was synthesized under the conditions of 6 GPa and 600 °C. The powder X-ray diffraction pattern of this new phase was indexed with a hexagonal cell of a = 9.968(1) Å and c = 3.2933(4) Å. Crystal structure refinement using synchrotron powder X-ray diffraction data led to RWP = 8.53% and RP = 5.55%, and the crystal structure was closely related with that of Ba2SrY6O12. No photocatalytic activity for phenol decomposition was observed under visible-light irradiation in spite of a good performance for its mother compound, NaBiO3. The optical band-gap energy of β-NaBiO3 was narrower than that of NaBiO3, which was confirmed with density of states curves simulated by first-principles density functional theory calculation. PMID:27243818

  5. Links Between Hydrothermal Environments, Pyrophosphate, Na+, and Early Evolution

    NASA Astrophysics Data System (ADS)

    Holm, Nils G.; Baltscheffsky, Herrick

    2011-10-01

    The discovery that photosynthetic bacterial membrane-bound inorganic pyrophosphatase (PPase) catalyzed light-induced phosphorylation of orthophosphate (Pi) to pyrophosphate (PPi) and the capability of PPi to drive energy requiring dark reactions supported PPi as a possible early alternative to ATP. Like the proton-pumping ATPase, the corresponding membrane-bound PPase also is a H+-pump, and like the Na+-pumping ATPase, it can be a Na+-pump, both in archaeal and bacterial membranes. We suggest that PPi and Na+ transport preceded ATP and H+ transport in association with geochemistry of the Earth at the time of the origin and early evolution of life. Life may have started in connection with early plate tectonic processes coupled to alkaline hydrothermal activity. A hydrothermal environment in which Na+ is abundant exists in sediment-starved subduction zones, like the Mariana forearc in the W Pacific Ocean. It is considered to mimic the Archean Earth. The forearc pore fluids have a pH up to 12.6, a Na+-concentration of 0.7 mol/kg seawater. PPi could have been formed during early subduction of oceanic lithosphere by dehydration of protonated orthophosphates. A key to PPi formation in these geological environments is a low local activity of water.

  6. Magnetism in Na-filled Fe-based skutterudites

    PubMed Central

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-01-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form. PMID:26027504

  7. Na(7)Mg(13)Nd(PO(4))(12).

    PubMed

    Jerbi, Hasna; Hidouri, Mourad; Mongi, Ben Amara

    2012-06-01

    Investigations of the quasi-ternary system Na(3)PO(4)-Mg(3)(PO(4))(2)-NdPO(4) allowed us to obtain the new phosphate hepta-sodium trideca-magnesium neodymium dodeca-kis-phosphate, Na(7)Mg(13)Nd(PO(4))(12), by applying a flux method. The crystal structure is isotypic with that of the previously reported Na(7)Mg(13)Ln(PO(4))(12) (Ln = Eu, La) compounds. It consists of a complex three-dimensional framework built up from an NdO(8) polyhedron (m symmetry), an MO(6) octa-hedron statistically occupied by M = Mg and Na, and eight MgO(x) (x = 5, 6) polyhedra (four with site symmetry m), linked either directely by sharing corners, edges and faces, or by one of the eight unique PO(4) tetra-hedra through common corners. Two of the PO(4) tetra-hedra are statisticaly disordered over a mirror plane. The whole structure can be described as resutling from an assembly of two types of structural units, viz [Mg(4)MP(4)O(22)](∞) (2) layers extending parallel to (100) and stacked along [100], and [Mg(4)NdP(4)O(36)](∞) (1) undulating chains running along the [010] direction. The six different Na(+) cations (five with site symmetry m and one with 0.5 occupancy) are situated in six distinct cavities delimited by the framework. The structure was refined from data of a racemic twin.

  8. Gramicidin A directly inhibits mammalian Na(+)/K (+)-ATPase.

    PubMed

    Takada, Yohei; Matsuo, Kentaro; Kataoka, Takao

    2008-12-01

    The linear pentadecapeptide gramicidin A forms an ion channel in the lipid bilayer to selectively transport monovalent cations. Nevertheless, we have surprisingly found that gramicidin A directly inhibits mammalian Na(+)/K(+)-ATPase. Gramicidin A inhibited ATP hydrolysis by Na(+)/K(+)-ATPase from porcine cerebral cortex at the IC(50) value of 8.1 microM, while gramicidin S was approximately fivefold less active. The synthetic gramicidin A analog lacking N-terminal formylation and C-terminal ethanolamine exhibited a weaker inhibitory effect on the ATP-hydrolyzing activity of Na(+)/K(+)-ATPase than gramicidin A, indicating that these end modifications are necessary for gramicidin A to inhibit Na(+)/K(+)-ATPase activity. Moreover, Lineweaver-Burk analysis showed that gramicidin A exhibits a mixed type of inhibition. In addition to the most well-studied ionophore activity, our present study has disclosed a novel biological function of gramicidin A as a direct inhibitor of mammalian Na(+)/K(+)-ATPase activity.

  9. The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

    PubMed

    Byrt, Caitlin Siobhan; Xu, Bo; Krishnan, Mahima; Lightfoot, Damien James; Athman, Asmini; Jacobs, Andrew Keith; Watson-Haigh, Nathan S; Plett, Darren; Munns, Rana; Tester, Mark; Gilliham, Matthew

    2014-11-01

    Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes. PMID:25158883

  10. The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

    PubMed

    Byrt, Caitlin Siobhan; Xu, Bo; Krishnan, Mahima; Lightfoot, Damien James; Athman, Asmini; Jacobs, Andrew Keith; Watson-Haigh, Nathan S; Plett, Darren; Munns, Rana; Tester, Mark; Gilliham, Matthew

    2014-11-01

    Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes.

  11. EDITORIAL: TaCoNa-Photonics 2008 TaCoNa-Photonics 2008

    NASA Astrophysics Data System (ADS)

    Chigrin, Dmitry N.; Busch, Kurt; Lavrinenko, Andrei V.

    2009-11-01

    This special section on theoretical and computational nano-photonics features papers presented at the first International Workshop on Theoretical and Computational Nano-Photonics (TaCoNa-Photonics 2008) held in Bad Honnef, Germany, 3-5 December 2008. The workshop covered a broad range of topics related to current developments and achievements in this interdisciplinary area of research. Since the late 1960s, the word `photonics' has been understood as the science of generating, controlling, and detecting light. Nowadays, a routine fabrication of complex structures with micro- and nano-scale dimensions opens up many new and exciting possibilities in photonics. The science of generating, routing and detecting light in micro- and nano-structured matter, `nano-photonics', is becoming more important both in research and technology and offers many promising applications. The inherently sub-wavelength character of the structures that nano-photonics deals with challenges modern theoretical and computational physics and engineering with many nontrivial questions: Up to what length-scale can one use a macroscopic phenomenological description of matter? Where is the interface between the classical and quantum description of light in nano-scale structures? How can one combine different physical systems, different time- and length-scales in a single computational model? How can one engineer nano-structured materials in order to achieve the desired optical properties for particular applications? Any attempt at answering these kinds of questions is impossible without the joint efforts of physicists, engineers, applied mathematicians and programmers. This is the reason why the major goal of the TaCoNa-Photonics workshops is to provide a forum where theoreticians and specialists in numerical methods from all branches of physics, engineering sciences and mathematics can compare their results, report on novel results and breakthroughs, and discuss new challenges ahead. In order to

  12. Results of tests of weathered K5NA closeout material in the MSFC Hot Gas Facility

    NASA Technical Reports Server (NTRS)

    Dean, W. G.

    1982-01-01

    The application of K5NA over hypolon was investigated. The effects of using K5NA over painted cork surfaces, the effects of weathering on the unpainted K5NA surfaces are determined, and the use of water versus solvent for tooling K5NA in place were compared. It is concluded that: (1) K5NA can be applied to hypalon surfaces; (2) K5NA can be left unpainted; and (3) K5NA can be tested with water or solvent.

  13. High-NA HPCS optical fibers for medical diagnosis and treatment

    NASA Astrophysics Data System (ADS)

    Skutnik, Bolesh J.

    2010-02-01

    Hard Plastic Clad Silica (HPCS) optical fibers with pure silica cores have been developed which are robust and have NA(Numerical Aperture)>0.50. Improved clad only HPCS fibers have been produced for both new 'standard' and 'high' NA versions. Based on new cladding formulations, the 'standard' NA fiber has an NA of 0.41, while the new ultrahigh NA fiber has an NA of 0.54. Mechanical strength and preliminary fatigue data are presented along with spectral characterization data. For the first time significant results were obtained for clad only high NA fibers, The fibers are useful for diagnostic and surgical applications. Short to medium length time to failure results, indicate that the static fatigue parameters of the new high numerical aperture (NA) optical fibers are at least as good as those for former standard NA (0.37) HPCS fibers, which is an advance from previous results on the older formulation high NA fibers.

  14. Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells

    PubMed Central

    Manoharan, Palanikumar; Gayam, Swapna; Arthur, Subha; Palaniappan, Balasubramanian; Singh, Soudamani; Dick, Gregory M.

    2015-01-01

    Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-d-[3H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter. PMID:25652450

  15. Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells.

    PubMed

    Manoharan, Palanikumar; Gayam, Swapna; Arthur, Subha; Palaniappan, Balasubramanian; Singh, Soudamani; Dick, Gregory M; Sundaram, Uma

    2015-04-15

    Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-D-[(3)H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter.

  16. Growth and electronic properties of NaCl on HOPG

    NASA Astrophysics Data System (ADS)

    Mahapatra, O.; Kowalczyk, P. J.; Brown, S. A.

    2014-02-01

    We report the growth of cross-shaped islands of NaCl on highly oriented pyrolytic graphite (HOPG) and discuss the mechanism of formation and growth kinetics within the framework of diffusion limited aggregation (DLA). These structures are investigated using scanning probe microscopy. The shape and structure of these islands can be finely controlled by the deposition conditions. The islands exhibit large atomically flat surfaces which are ideal supports for investigations of the fundamental properties of deposited atoms, molecules or clusters. Bismuth nanostructures were deposited on the NaCl islands and were investigated via scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The tunneling spectra recorded for particles on NaCl are surprisingly similar to those measured for similar particles on HOPG. We suggest that this is due to a 'dead' layer commonly observed for Bi thin films.

  17. Superconducting properties and electronic structure of NaBi.

    PubMed

    Kushwaha, S K; Krizan, J W; Xiong, J; Klimczuk, T; Gibson, Q D; Liang, T; Ong, N P; Cava, R J

    2014-05-28

    Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy. PMID:24804822

  18. HARP and NA61 (SHINE) hadron production experiments

    SciTech Connect

    Popov, Boris A.

    2009-11-25

    The hadroproduction experiments HARP and NA61 (SHINE) as well as their implications for neutrino physics are discussed. Recent HARP measurements have already been used for precise predictions of neutrino beams in K2K and MiniBooNE/SciBooNE experiments and are also being used to improve the atmospheric neutrino flux predictions and to help in the optimization of neutrino factory and super-beam designs. First preliminary data from NA61 are of significant importance for a precise prediction of a new neutrino beam at J-PARC to be used for the first stage of the T2K experiment. Both HARP and NA61 provide a large amount of input for validation and tuning of hadroproduction models in Monte-Carlo generators.

  19. Superconducting properties and electronic structure of NaBi.

    PubMed

    Kushwaha, S K; Krizan, J W; Xiong, J; Klimczuk, T; Gibson, Q D; Liang, T; Ong, N P; Cava, R J

    2014-05-28

    Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy.

  20. A pore segment in DEG/ENaC Na(+) channels.

    PubMed

    Snyder, P M; Olson, D R; Bucher, D B

    1999-10-01

    DEG/ENaC Na(+) channels have diverse functions, including Na(+) absorption, neurotransmission, and sensory transduction. The ability of these channels to discriminate between different ions is critical for their normal function. Several findings suggest that DEG/ENaC channels have a pore structure similar to K(+) channels. To test this hypothesis, we examined the accessibility of native and introduced cysteines in the putative P loop of ENaC. We identified residues that span a barrier that excludes amiloride as well as anionic and large methanethiosulfonate reagents from the pore. This segment contains a structural element ((S/G)CS) involved in selectivity of ENaC. The results are not consistent with predictions from the K(+) channel pore, suggesting that DEG/ENaC Na(+) channels have a novel pore structure. PMID:10497211

  1. Na3Al(AsO4)2

    PubMed Central

    Fakhar Bourguiba, Noura; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    The structure of the title compound tris­odium aluminium bis­(arsenate), Na3Al(AsO4)2, is built up from AlO4 and AsO4 corner-sharing tetra­hedra, forming an undulating two-dimensional framework parallel to (100). The layers are constituted of large Al6As6O36 rings made up from six AlO4 and AsO4 tetra­hedra in which two sodium cations are situated, the third sodium cation being located in the inter­layer space. The structural relationships between the title compound and Na3Fe(PO4)2, NaAlCo(PO4)2 and Al5Co3(PO4)8 are discussed. PMID:23424394

  2. Binding energy and structure of e{sup +}Na

    SciTech Connect

    Shertzer, J.; Ward, S. J.

    2010-06-15

    We calculate the nonadiabatic binding energy and geometry of the weakly bound state of e{sup +}Na. We use the Peach model potential, which includes both the dipole and an effective quadrupole term in the polarization, to describe the interaction of the electron and positron with the ion core. The effective three-body Schroedinger equation is solved with the finite element method. Because the model potential gives rise to three spurious states, the true ground state of e{sup +}Na is embedded in a dense spectrum of spurious states. We develop a method for extracting the correct ground state for e{sup +}Na, even when the energy is nearly degenerate with a spurious level. The calculated value for the binding energy is consistent with other calculations.

  3. Role of Na+ and K+ in enzyme function.

    PubMed

    Page, Michael J; Di Cera, Enrico

    2006-10-01

    Metal complexation is a key mediator or modifier of enzyme structure and function. In addition to divalent and polyvalent metals, group IA metals Na+ and K+ play important and specific roles that assist function of biological macromolecules. We examine the diversity of monovalent cation (M+)-activated enzymes by first comparing coordination in small molecules followed by a discussion of theoretical and practical aspects. Select examples of enzymes that utilize M+ as a cofactor (type I) or allosteric effector (type II) illustrate the structural basis of activation by Na+ and K+, along with unexpected connections with ion transporters. Kinetic expressions are derived for the analysis of type I and type II activation. In conclusion, we address evolutionary implications of Na+ binding in the trypsin-like proteases of vertebrate blood coagulation. From this analysis, M+ complexation has the potential to be an efficient regulator of enzyme catalysis and stability and offers novel strategies for protein engineering to improve enzyme function.

  4. The stability of sodalite in the system NaAlSiO sub 4 -NaCl

    SciTech Connect

    Sharp, Z.D. ); Helffrich, G.R. ); Bohlen, S.R. ); Essene, E.J. )

    1989-08-01

    The reaction sodalite = {beta}-nepheline + NaCl (s) was reversed in solid-medium apparatus and the reaction sodalite = carnegieite + NaCl (l) was reversed at 1 bar (1,649-1,652 K). The experimental reversals between 923 K and 973 K can be fit with a dP/dT of {minus}11 bar/K, suggesting that the excess entropy for sodalite is present only above 923 K. A phase diagram for the NaAlSiO{sub 4}-NaCl system that is consistent with the measured thermochemical data and the experiments between 973 and 1,650 K can be generated if the 61.7 J/mol{center dot}K entropy contribution is included in the S{sup 0}{sub 298} of sodalite. This entropy contribution must be removed below 973 K for the experiments to fit with calculations. Previously unreported thermodynamic data estimated in this study are {Delta}G{sup 0}{sub 298} for sodalite ({minus}12,697 kJ/mol) and carnegieite (NaAlSiO{sub 4}) ({minus}1,958 kJ/mol), S{sup 0}{sub 298} of carnegieite (129.6 J/mol{center dot}K) and compressibility of NaCl{sub liquid} (V{sup P}{sub 298} (cm{sup 3}) = 31.6{center dot}(1 - 24.7{center dot}10{sup {minus}3}{center dot}P + 800{center dot}10{sup {minus}6}{center dot}P{sup 2}))(T in K; P in kbar). Sodalite is a high-temperature, low-pressure phase, stable well above the solidus in sodic silica-undersaturated magmas enriched in NaCl, and its presence constrains NaCl activities in magmas. Estimates of minimum NaCl (l) activities in the Mont St-Hilaire sodalite syenites are 0.05 at 1,073 K and 0.13 at 1,273 K. Density calculations are consistent with the field observations that sodalite phenocrysts will float in a nepheline syenite liquid. This explains the enrichment of sodalite in the upper levels of the sodalite syenites at Mont St.Hilaire and elsewhere.

  5. Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries.

    PubMed

    Ortiz-Vitoriano, Nagore; Batcho, Thomas P; Kwabi, David G; Han, Binghong; Pour, Nir; Yao, Koffi Pierre Claver; Thompson, Carl V; Shao-Horn, Yang

    2015-07-01

    Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na-O2 battery performance. Here we show NaO2 as the only discharge product from Na-O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively.

  6. Plant response to Na/sup +/, K/sup +/ and K/sup +//Na/sup +/ ratios under saline conditions

    SciTech Connect

    Devitt, D.A.

    1983-01-01

    This research was undertaken to more clearly determine plant response to saline-sodic waters. In the first experiment, the response of wheat and sorghum to different K/sup +//Na/sup +/ ratios at different osmotic potentials was investigated. The plants were grown in outdoor solution culture tanks containing polyethylene glycol and/or NaCl as osmoticum with 1/2 strength Hoagland as the base nutrient solution. The mass of the root system for both wheat and sorghum was determined primarily by the osmotic potential. However, root elongation was controlled primarily by the Na/sup +/ concentration. Sorghum root elongation rates decreased with increasing Na/sup +/ while those for wheat increased. Sodium was not translocated out of the sorghum root system until a critical Na/sup +/ root saturation level of .6 moles/kg was obtained. The second experiment was designed to investigate the water, nutrient and growth responses of the second crop of wheat in a wheat-sorghum-wheat rotation to zonal saline-sodic conditions.

  7. Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries.

    PubMed

    Ortiz-Vitoriano, Nagore; Batcho, Thomas P; Kwabi, David G; Han, Binghong; Pour, Nir; Yao, Koffi Pierre Claver; Thompson, Carl V; Shao-Horn, Yang

    2015-07-01

    Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na-O2 battery performance. Here we show NaO2 as the only discharge product from Na-O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively. PMID:26266746

  8. Comparison of the Na(4p) + H2 and Na(3p) + H2 reactive/quenching systems studied with CARS, resonance-enhanced CARS, and DFWM

    NASA Astrophysics Data System (ADS)

    Motzkus, M.; Pichler, G.; Kompa, K. L.; Hering, P.

    1997-06-01

    Three different nonlinear optical techniques, CARS (coherent anti-Stokes Raman scattering), resonance-enhanced CARS, and DFWM (degenerate four-wave mixing), were used to compare the reactive and quenching behavior of the two different electronically excited sodium atoms, Na(3p) and Na(4p), in a collision with H2. In the chemical reaction channel both excited sodium states produce NaH molecules, but in the case of Na(3p) it is shown that the reaction is not a direct formation process and involves more than one step. Both sodium states induce a population of the vibrational levels v″=0-3 of NaH. For the Na(3p) excitation the population of the NaH molecules is concentrated at v″=0, whereas for the excitation of the Na(4p) state NaH has its maximum population in the v″=1 level. The differences are attributed to different potential energy surfaces. The quenching investigations were focused on the behavior of the Na(4p) state and the results were compared with the well-known behavior of the Na(3p) state. Because no quenching products were detected in the CARS spectra with Na(4p) excitation, the upper limit for the integrated quenching cross section was estimated to be less than 5×10-17 cm2, as based on the detection sensitivity of the CARS apparatus.

  9. Pancreatic β-cell Na+ channels control global Ca2+ signaling and oxidative metabolism by inducing Na+ and Ca2+ responses that are propagated into mitochondria.

    PubMed

    Nita, Iulia I; Hershfinkel, Michal; Kantor, Chase; Rutter, Guy A; Lewis, Eli C; Sekler, Israel

    2014-08-01

    Communication between the plasma membrane and mitochondria is essential for initiating the Ca(2+) and metabolic signals required for secretion in β cells. Although voltage-dependent Na(+) channels are abundantly expressed in β cells and activated by glucose, their role in communicating with mitochondria is unresolved. Here, we combined fluorescent Na(+), Ca(2+), and ATP imaging, electrophysiological analysis with tetrodotoxin (TTX)-dependent block of the Na(+) channel, and molecular manipulation of mitochondrial Ca(2+) transporters to study the communication between Na(+) channels and mitochondria. We show that TTX inhibits glucose-dependent depolarization and blocks cytosolic Na(+) and Ca(2+) responses and their propagation into mitochondria. TTX-sensitive mitochondrial Ca(2+) influx was largely blocked by knockdown of the mitochondrial Ca(2+) uniporter (MCU) expression. Knockdown of the mitochondrial Na(+)/Ca(2+) exchanger (NCLX) and Na(+) dose response analysis demonstrated that NCLX mediates the mitochondrial Na(+) influx and is tuned to sense the TTX-sensitive cytosolic Na(+) responses. Finally, TTX blocked glucose-dependent mitochondrial Ca(2+) rise, mitochondrial metabolic activity, and ATP production. Our results show that communication of the Na(+) channels with mitochondria shape both global Ca(2+) and metabolism signals linked to insulin secretion in β cells.- Nita, I. I., Hershfinkel, M., Kantor, C., Rutter, G. A., Lewis, E. C., Sekler, I. Pancreatic β-cell Na(+) channels control global Ca(2+) signaling and oxidative metabolism by inducing Na(+) and Ca(2+) responses that are propagated into mitochondria.

  10. Na+ conductivity of the Na+-driven flagellar motor complex composed of unplugged wild-type or mutant PomB with PomA.

    PubMed

    Takekawa, Norihiro; Terauchi, Takashi; Morimoto, Yusuke V; Minamino, Tohru; Lo, Chien-Jung; Kojima, Seiji; Homma, Michio

    2013-05-01

    PomA and PomB form the stator complex, which functions as a Na(+) channel, in the Na(+)-driven flagellar motor of Vibrio alginolyticus. The plug region of PomB is thought to regulate the Na(+) flow and to suppress massive ion influx through the stator channel. In this study, in order to measure the Na(+) conductivity of the unplugged stator, we over-produced a plug-deleted stator of the Na(+)-driven flagellar motor in Escherichia coli. The over-production of the plug-deleted stator in E. coli cells caused more severe growth inhibition than in Vibrio cells and that growth inhibition depended on the Na(+) concentration in the growth medium. Measurement of intracellular Na(+) concentration by flame photometry and fluorescent analysis with a Na(+) indicator, Sodium Green, revealed that over-production of the plug-deleted stator increased the Na(+) concentration in cell. Some mutations in the channel region of PomB or in the cytoplasmic region of PomA suppressed both the growth inhibition and the increase in intracellular Na(+) concentration. These results suggest that the level of growth inhibition correlates with the intracellular Na(+) concentration, probably due to the Na(+) conductivity through the stator due to the mutations. PMID:23420849

  11. A new low-voltage plateau of Na3V2(PO4)(3) as an anode for Na-ion batteries

    SciTech Connect

    Jian, ZL; Sun, Y; Ji, XL

    2015-01-01

    A low-voltage plateau at similar to 0.3 V is discovered for the deep sodiation of Na3V2(PO4)(3) by combined computational and experimental studies. This new low-voltage plateau doubles the sodiation capacity of Na3V2(PO4)(3), thus turning it into a promising anode for Na-ion batteries.

  12. Genetic Architecture of NaCl Tolerance in Arabidopsis1

    PubMed Central

    Quesada, Víctor; García-Martínez, Santiago; Piqueras, Pedro; Ponce, María Rosa; Micol, José Luis

    2002-01-01

    The little success of breeding approaches toward the improvement of salt tolerance in crop species is thought to be attributable to the quantitative nature of most, if not all the processes implicated. Hence, the identification of some of the quantitative trait loci (QTL) that contribute to natural variation in salt tolerance should be instrumental in eventually manipulating the perception of salinity and the corresponding responses. A good choice to reach this goal is the plant model system Arabidopsis, whose complete genome sequence is now available. Aiming to analyze natural variability in salt tolerance, we have compared the ability of 102 wild-type races (named ecotypes or accessions) of Arabidopsis to germinate on 250 mm NaCl, finding a wide range of variation among them. Accessions displaying extremely different responses to NaCl were intercrossed, and the phenotypes found in their F2 progenies suggested that natural variation in NaCl tolerance during germination was under polygenic controls. Genetic distances calculated on the basis of variations in repeat number at 22 microsatellites, were analyzed in a group of either extremely salt-tolerant or extremely salt-sensitive accessions. We found that most but not all accessions with similar responses to NaCl are phylogenetically related. NaCl tolerance was also studied in 100 recombinant inbred lines derived from a cross between the Columbia-4 and Landsberg erecta accessions. We detected 11 QTL harboring naturally occurring alleles that contribute to natural variation in NaCl tolerance in Arabidopsis, six at the germination and five at the vegetative growth stages, respectively. At least five of these QTL are likely to represent loci not yet described by their relationship with salt stress. PMID:12376659

  13. [Effects of NaCl stress on cation contents in different pumpkin cultivars' seedlings].

    PubMed

    Li, Wei-Xin; Chen, Gui-Lin; Ren, Liang-Yu; Wang, Peng

    2008-03-01

    With the seedlings of 19 pumpkin cultivars as test materials, this paper studied the variations of Na+, K+, Ca2+, Na+/K+, Na+/Ca2+, SN+, K+ and SNa+, ca2+ in their shoots and roots under the stress of 300 mmol NaCl x L(-1). The results showed that after an 8-day exposure to 300 mmol NaCl x L(-1), the Na+ content in the seedlings increased significantly while the K+ content decreased, resulting in the brokenness of ion balance. The root Na+ content, shoot Na+/K+ and Na+/Ca2+ ratios, and SNa+, K+ and SNa+, Ca2+ of Cucurbita moschata (Q1) were significantly higher than those of C. maxima (H2) and C. ficifolia (H3). The variation tendency of these parameters of different pumpkin cultivars' seedlings were nearly consistent with the salt injury index of the seedlings under NaCl stress, which further proved that the strong salt-tolerance of Q1 was related to the lower values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and the high contents of K+ and Ca2+, while the salt-sensitivity of H2 and H3 was related to the higher values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and low contents of K+ and Ca2+ under NaCl stress.

  14. Brain Na+, K+-ATPase Activity In Aging and Disease

    PubMed Central

    de Lores Arnaiz, Georgina Rodríguez; Ordieres, María Graciela López

    2014-01-01

    Na+/K+ pump or sodium- and potassium-activated adenosine 5’-triphosphatase (Na+, K+-ATPase), its enzymatic version, is a crucial protein responsible for the electrochemical gradient across the cell membranes. It is an ion transporter, which in addition to exchange cations, is the ligand for cardenolides. This enzyme regulates the entry of K+ with the exit of Na+ from cells, being the responsible for Na+/K+ equilibrium maintenance through neuronal membranes. This transport system couples the hydrolysis of one molecule of ATP to exchange three sodium ions for two potassium ions, thus maintaining the normal gradient of these cations in animal cells. Oxidative metabolism is very active in brain, where large amounts of chemical energy as ATP molecules are consumed, mostly required for the maintenance of the ionic gradients that underlie resting and action potentials which are involved in nerve impulse propagation, neurotransmitter release and cation homeostasis. Protein phosphorylation is a key process in biological regulation. At nervous system level, protein phosphorylation is the major molecular mechanism through which the function of neural proteins is modulted in response to extracellular signals, including the response to neurotransmitter stimuli. It is the major mechanism of neural plasticity, including memory processing. The phosphorylation of Na+, K+-ATPase catalytic subunit inhibits enzyme activity whereas the inhibition of protein kinase C restores the enzyme activity. The dephosphorylation of neuronal Na+, K+-ATPase is mediated by calcineurin, a serine / threonine phosphatase. The latter enzyme is involved in a wide range of cellular responses to Ca2+ mobilizing signals, in the regulation of neuronal excitability by controlling the activity of ion channels, in the release of neurotransmitters and hormones, as well as in synaptic plasticity and gene transcription. In the present article evidence showing Na+, K+-ATPase involvement in signaling pathways

  15. Optically stimulated luminescence in doped NaCl

    NASA Astrophysics Data System (ADS)

    Gaikwad, S. U.; Patil, R. R.; Kulkarni, M. S.; Bhatt, B. C.; Moharil, S. V.

    2016-05-01

    NaCl:Ca,Cu,P NaCl:Mg,Cu,P OSL phosphors are synthesized. Intense OSL is observed in these samples which is 14 times more than Al2O3:C. Same samples coated with PVA (poly vinyl actetae) polymer also show similar OSL properties and these coated samples are found to be less susceptible to the moisture due to protected layer of hydrophobic polymer. These coated samples may be useful as OSL dosimetersdue to high sensitivity and less or no susceptibility to moisture.

  16. Possible selective adsorption of enantiomers by Na-montmorillonite

    NASA Technical Reports Server (NTRS)

    Friebele, E.; Shimoyama, A.; Ponnamperuma, C.

    1981-01-01

    Racemic amino acids including (D,L) alpha-alamine, (D,L) alpha-aminobutyric acid, (D,L) valine, and (D,L) norvaline were incubated with Na-montmorillonite at 100% CEC at three hydrogen ion concentrations, and amino acid adsorption was determined by ion exchange chromatography. Enantiomers were analyzed by gas chromatography. Differences in the quantities of D and L enantiomers in any of the fractions was no larger than a few percent. Although a large difference in the adsorption of the amino acid enantiomers was not observed, the analysis may indicate a small preferential adsorption (0.5-2%) of L-amino acids by Na-montmorillonite.

  17. Measurements of electric discharge characteristics in NaCl solution

    NASA Astrophysics Data System (ADS)

    Ablesimov, V. E.; Karyuk, V. M.; Pavlov, A. N.; Kirpichev, A. A.; Simchuk, A. A.

    2015-03-01

    The characteristics of electric discharge in a NaCl solution with a specific concentration of up to ˜1.7% (electrical conductivity up to 0.032 Sm/cm) are investigated. The discharge is produced by the Era-1 discharger in a vessel filled with water or a NaCl solution. We obtain the dependences of the maximal discharge current, pressure pulse, and the pressure amplitude at the shock front at a distance of 7 cm from the discharge axis on the electrolyte concentration.

  18. Russian Scientific-Educational Project: Kazan-GeoNa-2017

    NASA Astrophysics Data System (ADS)

    Gusev, A.; Alibekova, N.

    2012-09-01

    For the further successful development of educational and scientific - educational activity of the Russian Federation, the Republic Tatarstan, Kazan is offered the national project - the International Center of the Science and the Internet of Technologies. "GeoNa" (Geometry of Nature - "GeoNa" is developed - wisdom, enthusiasm, pride, grandeur), which includes a modern complex of conference halls (up to 4 thousand places), the Center the Internet of Technologies, 3D Planetarium - development of the Moon, PhysicsLand, an active museum of natural sciences, an oceanarium, training a complex «Spheres of Knowledge», botanical and landscape oases.

  19. Structural Integrity and Microstructure of NA^+ Conducting Ceramics

    NASA Astrophysics Data System (ADS)

    Lipinska, Kristina; Kalita, Patricia; Hemmers, Oliver; Sinogeikin, Stanislav; Shebanova, Olga; Yang, Wenge; Mariotto, Gino

    2010-03-01

    Oxides with the general formula of Na1+x Zr2 Six P3-x O12 , known as Nasicon, are fast Na+ ion-conducting materials with important electrochemical applications and many functional properties, often attributed to their unique structural features. Comparative, in situ studies of the limits of structural integrity were performed for selected Nasicon materials, using synchrotron x-ray diffraction and diamond anvil cell technology. We show how different processing conditions produce crystalline structures with specific morphology. We discuss the bulk modulus, the compressibility and the influence of the volume fraction of primary and secondary crystalline phases on the overall Nasicon structural integrity.

  20. Regulation of cough by neuronal Na(+)-K(+) ATPases.

    PubMed

    Canning, Brendan J; Farmer, David G S

    2015-06-01

    The Na(+)-K(+) ATPases play an essential role in establishing the sodium gradients in excitable cells. Multiple isoforms of the sodium pumps have been identified, with tissue and cell specific expression patterns. Because the vagal afferent nerves regulating cough must be activated at sustained high frequencies of action potential patterning to achieve cough initiation thresholds, it is a certainty that sodium pump function is essential to maintaining cough reflex sensitivities in health and in disease. The mechanisms by which Na(+)-K(+) ATPases regulate bronchopulmonary vagal afferent nerve excitability are reviewed as are potential therapeutic strategies targeting the sodium pumps in cough.

  1. Toward Triplet Ground State NaLi Molecules

    NASA Astrophysics Data System (ADS)

    Ebadi, Sepehr; Jamison, Alan; Rvachov, Timur; Jing, Li; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    The NaLi molecule is expected to have a long lifetime in the triplet ground-state due to its fermionic nature, large rotational constant, and weak spin-orbit coupling. The triplet state has both electric and magnetic dipole moments, affording unique opportunities in quantum simulation and ultracold chemistry. We have mapped the excited state NaLi triplet potential by means of photoassociation spectroscopy. We report on this and our further progress toward the creation of the triplet ground-state molecules using STIRAP. NSF, ARO-MURI, Samsung, NSERC.

  2. Efficiency of the Modular Neutron Array (MoNA)

    NASA Astrophysics Data System (ADS)

    Peters, W. A.; Baumann, T.; Christian, G. A.; Denby, D.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Hall, C. C.; Hinnefeld, J.; Schiller, A.; Strongman, M. J.; Thoennessen, M.

    2009-03-01

    The efficiency of the Modular Neutron Array (MoNA), located at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, was measured and compared to simulations. The Coulomb dissociation of a 90 MeV/u beam of 11Be in a gold target was used to produce neutrons. The expected neutron production rate was calculated using the virtual photon method. The measured efficiency agrees with the efficiency calculated with GEANT simulations. The current configuration of MoNA has a 73% intrinsic detection efficiency for 90 MeV neutrons.

  3. Study of resonant scattering of 21Na+p relevant to astrophysical 18Ne(α,p)21Na reaction

    NASA Astrophysics Data System (ADS)

    He, J. J.; Zhang, L. Y.; Xu, S. W.; Chen, S. Z.; Hu, J.; Ma, P.; Chen, R. F.; Yamaguchi, H.; Kubono, S.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Wakabayashi, Y.; Togano, Y.; Wang, H. W.; Tian, W. D.; Guo, B.; Teranishi, T.; Iwasa, N.; Yamada, T.; Komatsubara, T.

    2012-11-01

    Astrophysical 18Ne(α,p)21Na reaction is one of the most probable breakout routes, which lead to the rp-process from the hot-CNO cycle, converting the initial CNO elements into heavier elements in Type I x-ray bursters. Presently, there is no much experimental cross-section data reported at the energy of astrophysical interest, and resonant spectroscopic information in compound 22Mg is scarce as well. The experiment has been carried out by using the CNS radioactive ion beam separator (CRIB). Resonant properties in 22Mg have been studied via the resonant elastic scattering of 21Na+p, and cross section of the time-reversal reaction of 21Na(p,α)18Ne been measured simultaneously. A wide excitation energy region up to Ex ~ 9.5 MeV in 22Mg has been scanned with a thick-target method. Some preliminary results will be reported.

  4. Toward a cold hybrid-trap measurement of charge-exchange between Na and Ca+: Na excited state fraction

    NASA Astrophysics Data System (ADS)

    Wells, James E.; Goodman, Douglas S.; Kwolek, Jonathan M.; Blumel, Reinhold; Narducci, Frank A.; Smith, Winthrop W.

    2015-05-01

    We present progress towards the measurement of the charge-exchange collision rate coefficient between neutral sodium and ionic calcium. The rate constant for charge exchange between ground state sodium and calcium ion has been previously calculated and predicts a lifetime in our system of the order of days. Experiments by our group show a much larger charge exchange collision rate, probably from the excited 3P state of sodium. Therefore, an accurate measurement of the charge exchange collision rate constant will require an accurate value for the excited state fraction of the Na MOT. We have developed a technique for making a model-independent measurement of the excited state fraction of a MOT inside a hybrid trap. We compare the measured excited state fraction using this technique with measurements assuming a two-level model of the atom. In addition, we review our recent measurement of the total elastic and resonant charge exchange collision rate between Na and Na+.

  5. Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium.

    PubMed

    Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A

    2015-10-01

    The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system.

  6. Physiological interactions between Na(v)1.7 and Na(v)1.8 sodium channels: a computer simulation study.

    PubMed

    Choi, Jin-Sung; Waxman, Stephen G

    2011-12-01

    We have examined the question of how the level of expression of sodium channel Na(v)1.8 affects the function of dorsal root ganglion (DRG) neurons that also express Na(v)1.7 channels and, conversely, how the level of expression of sodium channel Na(v)1.7 affects the function of DRG neurons that also express Na(v)1.8, using computer simulations. Our results demonstrate several previously undescribed effects of expression of Na(v)1.7: 1) at potentials more negative than -50 mV, increasing Na(v)1.7 expression reduces current threshold. 2) Na(v)1.7 reduces, but does not eliminate, the dependence of action potential (AP) threshold on membrane potential. 3) In cells that express Na(v)1.8, the presence of Na(v)1.7 results in larger amplitude subthreshold oscillations and increases the frequency of repetitive firing. Our results also demonstrate multiple effects of expression of Na(v)1.8: 1) dependence of current threshold on membrane potential is eliminated or reversed by expression of Na(v)1.8 at ≥50% of normal values. 2) Expression of Na(v)1.8 alone, in the absence of Na(v)1.7, can support subthreshold oscillation. 3) Na(v)1.8 is required for generation of overshooting APs, and its expression results in a prolonged AP with an inflection of the falling phase. 4) Increasing levels of expression of Na(v)1.8 result in a reduction in the voltage threshold for AP generation. 5) Increasing levels of expression of Na(v)1.8 result in an attenuation of Na(v)1.7 current during activity evoked by sustained depolarization due, at least in part, to accumulation of fast inactivation by Na(v)1.7 following the first AP. These results indicate that changes in the level of expression of Na(v)1.7 and Na(v)1.8 may provide a regulatory mechanism that tunes the excitability of small DRG neurons. PMID:21940606

  7. Magnetic properties of ternary sodium oxides Na LnO 2 ( Ln=rare earths)

    NASA Astrophysics Data System (ADS)

    Hashimoto, Yuta; Wakeshima, Makoto; Hinatsu, Yukio

    2003-11-01

    Magnetic properties of ternary sodium oxides Na LnO 2 ( Ln=rare earths) are investigated. Their crystal structures are grouped into three types of structures, which are α-LiFeO 2, β-LiFeO 2, and α-NaFeO 2, depending on the size of rare earths. Their magnetic susceptibilities and specific heats have been measured from 1.8 to 300 K. Among them, NaGdO 2, NaDyO 2, and NaHoO 2 show antiferromagnetic transitions at 2.4, 2.2, and 2.4 K, respectively, and NaNdO 2 transforms to the ferromagnetic state below 2.4 K. NaSmO 2, NaErO 2, and NaYbO 2 exhibit a magnetic anomaly below 1.8 K.

  8. Stainless Steel NaK Circuit Integration and Fill Submission

    NASA Technical Reports Server (NTRS)

    Garber, Anne E.

    2006-01-01

    The Early Flight Fission Test Facilities (EFF-TF) team has been tasked by the Marshall Space Flight Center Nuclear Systems Office to design, fabricate, and test an actively pumped alkali metal flow circuit. The system, which was originally designed to hold a eutectic mixture of sodium potassium (NaK), was redesigned to hold lithium; but due to a shift in focus, it is once again being prepared for use with NaK. Changes made to the actively pumped, high temperature loop include the replacement of the expansion reservoir, addition of remotely operated valves, and modification of the support table. Basic circuit components include: reactor segment, NaK to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and a spill reservoir. A 37-pin partial-array core (pin and flow path dimensions are the same as those in a full design) was selected for fabrication and test. This document summarizes the integration and fill of the pumped liquid metal NaK flow circuit.

  9. Substituting KCl for NaCl in fresh Queso Fresco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing the sodium level in cheese is challenging when a signature salty flavor is expected, such as in high-moisture Queso Fresco (QF). Fresh starter-free QF was fine milled and dry salted at different levels of NaCl and KCl to obtain total salt levels of 1.5 to 2.0%. The treatments contained 1....

  10. Rechargeable Room-Temperature Na-CO2 Batteries.

    PubMed

    Hu, Xiaofei; Sun, Jianchao; Li, Zifan; Zhao, Qing; Chen, Chengcheng; Chen, Jun

    2016-05-23

    Developing rechargeable Na-CO2 batteries is significant for energy conversion and utilization of CO2 . However, the reported batteries in pure CO2 atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g(-1) . Herein, we realized the rechargeability of a Na-CO2 battery, with the proposed and demonstrated reversible reaction of 3 CO2 +4 Na↔2 Na2 CO3 +C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g(-1) at 1 A g(-1) (≈1000 Wh kg(-1) ) and runs for 200 cycles with controlled capacity of 2000 mAh g(-1) at charge voltage <3.7 V. The porous structure, high electro-conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO2 .

  11. Separating Silicon From Si/NaF Mixtures

    NASA Technical Reports Server (NTRS)

    Sanjurjo, A.; Nanis, L.

    1982-01-01

    New method of extracting silicon from mixture produced when silicon tetrafluoride is reduced by sodium takes advantage of lower melting point of NaF. Method is effective at temperatures up to 400 degrees C below melting point of Si. Results in energy and economic savings: simpler and smaller furnaces, less volatization loss, and high percentage of separation.

  12. Ultraweak bioluminescence of maize under NaCl stress

    NASA Astrophysics Data System (ADS)

    Xie, Zhaohui

    2009-11-01

    In this paper, the delayed ultra-weak luminescence (UWL), leaf dry/fresh weight and reactive oxygen species (ROS) of the maize (Jundan 20) were investigated under various NaCl concentration. The results showed that following with the increase of NaCl, ROS contents increased obviously, but the UWL intensity decreased, and the decrease speed increased following with the increase of NaCl concentration, the decrease extent of delayed luminescence ranged from 10.4% to 27.2%. It was also found that both dry and fresh weight of seedling leaves decreased, but the ratio of dry/fresh weight increased. According to these results, we speculated that the decrease of UWL was mainly closely associated with the destruction of seedling normal physiological activities and metabolic disorder which were caused by NaCl stress, rather than ROS only. This study revealed that the spectral analysis of UWL is a useful tool for studying plant response to salt stress.

  13. Bilingual Education at Dzil Na'oodilii Community School.

    ERIC Educational Resources Information Center

    Howard, Roy E.

    Proceedings of a Navajo Bilingual Education Conference held April 26 and 27, 1985, are summarized in this report which focuses on the implementation of Navajo language and cultural education at the Dzlith Na O Dith Hle Community School (DCS). The paper begins by stating that the conference was intended to assist educators in understanding and…

  14. Neutral Na in comets tails: a chemical story

    NASA Astrophysics Data System (ADS)

    Ellinger, Y.; Pauzat, F.; Mousis, O.; Guilbert-Lepoutre, A.; Leblanc, F.; Ali-Dib, M.; Doronin, M.; Zicler, E.; Doressoundiram, A.

    2015-10-01

    The origin of the neutral sodium comet tail discovered in comet Hale-Bopp in 1997 is still a matter of discussion. Here we propose a scenario which is based on chemical grounds. The starting point is the chemical trapping of the Na+ ion in the refractory material during the condensation phase of the protosolar nebula, followed by its incorporation in the building blocks of the comets parent bodies. In the next step, the Na+ ions are washed out of the refractory material by the water formed by the melting of the ice due to the heat released in the radioactive decay of short period elements. When the water freezes again, the Na+ ion looses its positive charge to evolve progressively toward a neutral atom when approaching the surface of the ice. As shown by high-level numerical simulations based on first principle periodic density functional theory (DFT) to describe the solid structure of the ice, it is a neutral Na that is ejected with the sublimation of the ice top layer.

  15. Plasmalemmal and mitochondrial Na(+) -Ca(2+) exchange in neuroglia.

    PubMed

    Parpura, Vladimir; Sekler, Israel; Fern, Robert

    2016-10-01

    In the absence of the electrical signaling for which neurons are so highly specialized, GLIA rely on the slow propagation of ionic signals to mediate network events such as Ca(2+) and Na(+) waves. Glia differ from neurons in another important way, they are replete with a high density of ionic-transport proteins that are essential for them to fulfil their basic functions as guardians of the intra and extra-cellular milieux. Both the signaling and the homeostatic properties of glial cells are therefore particularly dependent upon the regulation of the two principle physiological metal cations, Ca(2+) and Na(+) . For both ions, glia express high-affinity/low capacity ATP-fuelled pumps that can rapidly move small numbers of ions against an electro-chemical gradient. For both Ca(2+) and Na(+) regulation, a single transporter family, the Na(+) -Ca(2+) exchanger (NCX), is used to maintain cellular ion homeostasis over the longer term and under conditions of prolonged or acute ionic dysregulation in astrocytes, oligodendroglia and microglia. Our understanding of glial NCX, both plasmalemmal and mitochondrial, is undergoing the kind of transformation that our understanding of glial cells, in general, has undergone in recent decades. These exchange proteins are becoming increasingly recognized for their essential roles in intracellular homeostasis while their signaling functions are starting to come to light. This review summarizes these key aspects and highlights the many areas where work has yet to begin in this rapidly evolving field. GLIA 2016;64:1646-1654. PMID:27143128

  16. Search for Na+ Pickup Ion Generated Waves at Mercury

    NASA Astrophysics Data System (ADS)

    Boardsen, S. A.; Slavin, J. A.

    2007-05-01

    Telescopic observations by Potter et al. [2002] have discovered that Mercury's Sodium exosphere has a tail extending 10's of Mercury radii. Theory predicts that the shape of and the amount of Sodium [Smyth, 1986, 1995; Ip 1986, 1990] in this exospheric tail is highly dependent upon the true anomaly of Mercury. The exospheric Na that is not reabsorbed on Mercury's surface will be photo-ionized. Computations by Ip [1986] indicated that ionized exospheric Na could significantly mass load the plasma population in Mercury's magnetosphere. These freshly created ions will be rapidly energized by the convection electric field in Mercury's magnetosphere and sheath and should be highly unstable to the generation of plasma waves. These waves could play an important role in the thermalization and retention of the Na+. Because the gyro radii of Na+ can be comparable to the scale sizes in Mercury's geospace there is an open question whether Mercury's geospace can sustain such waves. After a brief review of what was observed in the Mariner 10 magnetometer data, we will present analytic calculations of the expected pickup ion distributions, the expected unstable waves, their frequencies, wavelengths and Doppler shifts, their variation with location in Mercury's geospace and Mercury's true anomaly for both high and low solar wind convection electric fields. We will assess if and when such waves can be generated and sustained.

  17. Rechargeable Room-Temperature Na-CO2 Batteries.

    PubMed

    Hu, Xiaofei; Sun, Jianchao; Li, Zifan; Zhao, Qing; Chen, Chengcheng; Chen, Jun

    2016-05-23

    Developing rechargeable Na-CO2 batteries is significant for energy conversion and utilization of CO2 . However, the reported batteries in pure CO2 atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g(-1) . Herein, we realized the rechargeability of a Na-CO2 battery, with the proposed and demonstrated reversible reaction of 3 CO2 +4 Na↔2 Na2 CO3 +C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g(-1) at 1 A g(-1) (≈1000 Wh kg(-1) ) and runs for 200 cycles with controlled capacity of 2000 mAh g(-1) at charge voltage <3.7 V. The porous structure, high electro-conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO2 . PMID:27089434

  18. Plasmalemmal and mitochondrial Na(+) -Ca(2+) exchange in neuroglia.

    PubMed

    Parpura, Vladimir; Sekler, Israel; Fern, Robert

    2016-10-01

    In the absence of the electrical signaling for which neurons are so highly specialized, GLIA rely on the slow propagation of ionic signals to mediate network events such as Ca(2+) and Na(+) waves. Glia differ from neurons in another important way, they are replete with a high density of ionic-transport proteins that are essential for them to fulfil their basic functions as guardians of the intra and extra-cellular milieux. Both the signaling and the homeostatic properties of glial cells are therefore particularly dependent upon the regulation of the two principle physiological metal cations, Ca(2+) and Na(+) . For both ions, glia express high-affinity/low capacity ATP-fuelled pumps that can rapidly move small numbers of ions against an electro-chemical gradient. For both Ca(2+) and Na(+) regulation, a single transporter family, the Na(+) -Ca(2+) exchanger (NCX), is used to maintain cellular ion homeostasis over the longer term and under conditions of prolonged or acute ionic dysregulation in astrocytes, oligodendroglia and microglia. Our understanding of glial NCX, both plasmalemmal and mitochondrial, is undergoing the kind of transformation that our understanding of glial cells, in general, has undergone in recent decades. These exchange proteins are becoming increasingly recognized for their essential roles in intracellular homeostasis while their signaling functions are starting to come to light. This review summarizes these key aspects and highlights the many areas where work has yet to begin in this rapidly evolving field. GLIA 2016;64:1646-1654.

  19. Results from NA60 experiment at the CERN SPS

    SciTech Connect

    Usai, G.; Cicalo, C.; De Falco, A.; Floris, M.; Masoni, A.; Puddu, G.; Serci, S.; Arnaldi, R.; Colla, A.; Cortese, P.; Ferretti, A.; Oppedisano, C.; Averbeck, R.; Drees, A.; Banicz, K.; Castor, J.; Devaux, A.; Force, P.; Manso, F.; Chaurand, B.

    2006-07-11

    The NA60 experiment studies open charm and prompt dimuon production in proton-nucleus and nucleus-nucleus collisions at the CERN SPS. During 2003 the experiment collected data in Indium-Indium collisions at 158 GeV per nucleon. In this paper the first results on low mass dimuons, intermediate mass dimuons and J/{psi} suppression are presented.

  20. Reductive amination of carbohydrates using NaBH(OAc)3.

    PubMed

    Dalpathado, Dilusha S; Jiang, Hui; Kater, Marcus A; Desaire, Heather

    2005-03-01

    An improved protocol for reductive amination of carbohydrates is developed. This derivatization facilitates the detection of oligosaccharides in HPLC-UV and mass spectrometric applications by enhancing the signal of the carbohydrates. In this study, reductive amination was achieved using NaBH(OAc)3. This reducing agent is an attractive alternative to the toxic, but extensively used reducing agent, NaBH3CN. Several types of carbohydrates were successfully derivatized using NaBH(OAc)3, and the results obtained from this protocol were compared with those obtained with NaBH(OAc)3. Both reducing agents were equally effective in side-by-side analysis. Two purification strategies (purification by zip-tip and HPLC) were implemented and the instrumental limit of detection of each method was compared. The detection limit was approximately 1,000 times lower when the purification was done using HPLC, compared to using the zip-tip. Since the derivatization by-products in this protocol are not toxic, MS analysis also could also be performed directly, without purification. The MS/MS data of derivatized and underivatized oligosaccharides were acquired as well. The derivatized oligosaccharides produce more easily interpretable product ions than underivatized oligosaccharides.

  1. Multimodal action of single Na+ channels in myocardial mouse cells.

    PubMed

    Böhle, T; Benndorf, K

    1995-01-01

    Unitary Na+ currents of myocardial mouse cells were studied at room temperature in 10 cell-attached patches, each containing one and only one channel. Small-pore patch pipettes (resistance 10-97 M omega when filled with 200% Tyrode's solution) with exceptionally thick walls were used. Observed were both rapidly inactivating (6 patches) and slowly inactivating (3 patches) Na+ currents. In one patch, a slow transition from rather fast to slow inactivation was detected over a time of 0.5 h. A short and a long component of the open-channel life time were recorded at the beginning, but only a short one at the end of the experiment. Concomitantly, the first latency was slowed. Amplitude histograms showed that the electrochemical driving force across the pore of the channel did not change during this time. In three patches, a fast and repetitive switching between different modes of Na+ channel action could be clearly identified by plotting the long-time course of the averaged current per trace. The ensemble-averaged current formed in each mode was different in kinetics and amplitude. Each mode had a characteristic mean open-channel life time and distribution of first latency, but the predominant single-channel current amplitude was unaffected by mode switches. It is concluded that two types of changes in kinetics may happen in a single Na+ channel: fast and reversible switches between different modes, and a slow loss of inactivation.

  2. Project ELaNa and NASA's CubeSat Initiative

    NASA Technical Reports Server (NTRS)

    Skrobot, Garrett Lee

    2010-01-01

    This slide presentation reviews the NASA program to use expendable lift vehicles (ELVs) to launch nanosatellites for the purpose of enhancing educational research. The Education Launch of Nanosatellite (ELaNa) project, run out of the Launch Services Program is requesting proposals for CubeSat type payload to provide information that will aid or verify NASA Projects designs while providing higher educational research

  3. Luminescence and radiation resistance of undoped NaI crystals

    SciTech Connect

    Shiran, N. Boiaryntseva, I.; Gektin, A.; Gridin, S.; Shlyakhturov, V.; Vasuykov, S.

    2014-11-15

    Highlights: • The performance of NaI scintillators depends on luminescence properties. • A criterion of crystals’ purity level is radiation colorability at room temperature. • The traces of the most dangerous impurities were detected. • Crucial role in efficiency of pure NaI scintillator play the crystal perfection. - Abstract: Undoped NaI single crystal is an excellent scintillator at low temperature. However, scintillation parameters of different quality crystals vary in a wide range, significantly exceeding measurement error. Experimental data demonstrate the features of luminescence, radiation induced coloration, and afterglow dependence on the quality of nominally pure crystals. It is found that defects level that allows to elucidate artefacts introduced by traces of harmful impurities corresponds to 3 × 10{sup 15} cm{sup −3} that significantly overhead accuracy of chemical and absorption analysis. It is shown that special raw material treatment before and during the single crystal growth allows to reach NaI purity level that avoids impurities influence to the basic luminescence data.

  4. Altered erythrocyte Na-K pump in anorectic patients

    SciTech Connect

    Pasquali, R.; Strocchi, E.; Malini, P.; Casimirri, F.; Ambrosioni, E.; Melchionda, N.; Labo, G.

    1985-07-01

    The status of the erythrocyte sodium pump was evaluated in a group of patients suffering from anorexia nervosa and a group of healthy female control subjects. Anorectic patients showed significantly higher mean values of digoxin-binding sites/cell (ie, the number of Na-K-ATPase units) with respect to control subjects while no differences were found in the specific /sup 86/Rb uptake (which reflects the Na-K-ATPase activity) between the two groups. A significant correlation was found between relative weight and the number of Na-K-ATPase pump units (r = -0.66; P less than 0.0001). Anorectic patients showed lower serum T3 concentrations (71.3 +/- 53 ng/dL) with respect to control subjects (100.8 +/- 4.7 ng/dL; P less than 0.0005) and a significant negative correlation between T3 levels and the number of pump units (r = -0.52; P less than 0.003) was found. This study therefore shows that the erythrocyte Na-K pump may be altered in several anorectic patients. The authors suggest that this feature could be interrelated with the degree of underweight and/or malnutrition.

  5. Na+ Transport in Cardiac Myocytes; Implications for Excitation-Contraction Coupling

    PubMed Central

    Bers, Donald M.; Despa, Sanda

    2009-01-01

    Intracellular Na+ concentration ([Na+]i) is very important in modulating the contractile and electrical activity of the heart. Upon electrical excitation of the myocardium, voltage-dependent Na+ channels open, triggering the upstroke of the action potential (AP). During the AP, Ca2+ enters the myocytes via L-type Ca2+ channels. This triggers Ca2+ release from the sarcoplasmic reticulum (SR) and thus activates contraction. Relaxation occurs when cytosolic Ca2+ declines, mainly due to re-uptake into the SR via SR Ca2+-ATPase and extrusion from the cell via the Na+/Ca2+ exchanger (NCX). NCX extrudes one Ca2+ ion in exchange for three Na+ ions and its activity is critically regulated by [Na+]i. Thus, via NCX, [Na+]i is centrally involved in the regulation of intracellular [Ca2+] and contractility. Na+ brought in by Na+ channels, NCX and other Na+ entry pathways is extruded by the Na+/K+ pump (NKA) to keep [Na+]i low. NKA is regulated by phospholemman, a small sarcolemmal protein that associates with NKA. Unphosphorylated phospholemman inhibits NKA by decreasing the pump affinity for internal Na+ and this inhibition is relieved upon phosphorylation. Here we discuss the main characteristics of the Na+ transport pathways in cardiac myocytes and their physiological and pathophysiological relevance. PMID:19243007

  6. Multiple quantum filtered (23)Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i.

    PubMed

    Eykyn, Thomas R; Aksentijević, Dunja; Aughton, Karen L; Southworth, Richard; Fuller, William; Shattock, Michael J

    2015-09-01

    We investigate the potential of multiple quantum filtered (MQF) (23)Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32±6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the (23)Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM(3SA) mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered (23)Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation.

  7. Multiple quantum filtered 23Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i

    PubMed Central

    Eykyn, Thomas R.; Aksentijević, Dunja; Aughton, Karen L.; Southworth, Richard; Fuller, William; Shattock, Michael J.

    2015-01-01

    We investigate the potential of multiple quantum filtered (MQF) 23Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32 ± 6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the 23Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM3SA mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered 23Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation. PMID:26196304

  8. Effects of Na2MoO4 and Na2WO4 on molybdenum and tungsten electrodes for the alkali metal thermoelectric converter (AMTEC)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Wheeler, B. L.; Jeffries-Nakamura, B.; Loveland, M. E.; Bankston, C. P.

    1988-01-01

    The effects of adding Na2MoO4 and Na2WO4 to porous Mo and W electrodes, respectively, on the performance and impedance characteristics of the electrodes in an alkali metal thermoelectric converter (AMTEC) were investigated. It was found that corrosion of the porous electrode by Na2MoO4 or Na2WO4 to form Na2MO3O6 and WO2, respectively, and recrystallization of the Mo or W as the salt evaporates, result in major morphological changes including a loss of columnar structure and a significant increase in porosity. This effect is more pronounced in Na2MoO4/Mo electrodes, due to the lower stability of Na2MoO4.

  9. The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

    PubMed

    Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

    2014-01-15

    (23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one. PMID:24139955

  10. Charge order and anomalous magnetism in the Na cobaltates

    NASA Astrophysics Data System (ADS)

    Alloul, Henri

    2008-03-01

    The layered Na cobaltates have some analogies with the cuprates as 2D conductivity occurs in the CoO2 planes and doping can be modified by changing the Na content. Also ordered magnetic phases have been evidenced, but unexpectedly for large values of x for which one would expect a hole doping of the band insulator NaCoO2. Indeed, in the high crystal field on the Co sites in these compounds, an ionic picture for the Co states would correspond to low spin configurations Co^3+, S=0 or Co^4+, S=1/2. We shall present SQUID and ^23Na and ^59Co NMR data [1] taken on samples synthetized and characterized by X ray cristallography in LLB, Saclay. We evidence that the Co charge is uniform for x=0.35 as in the hydrated superconducting phase. For high Na contents the samples are found to display ordered Na structures or mixtures of those, with different x values. In pure phases isolated for specific x values, we evidence a charge disproportionation into non magnetic Co^3+ and more magnetic Co sites with an average charge of about Co^3.5+, except for x=0.5 [2]. This hole delocalization and charge order occur both for paramagnetic and AF phases [3]. NMR investigations of the dynamic susceptibilities allow us to characterize the nature of the in plane electronic correlations in most parts of the phase diagram. Contrary to the case of most cuprates for which dopant disorder is quite influential, the hole doping achieved in cobaltate samples is associated with the insertion of well ordered Na planar structures. They have to be taken into account to explain theoretically the metallicity, the magnetic properties and their evolution with doping. [1] I. Mukhamedchine, H. Alloul, G. Collin et N. Blanchard, Phys. Rev. Letters, 94, 247602 (2005). [2] http://arxiv.org/find/cond-mat/1/au:+BobroffJ/0/1/0/all/0/1, J. Bobroff; http://arxiv.org/find/cond-mat/1/au:+LangG/0/1/0/all/0/1, G. Lang; http://arxiv.org/find/cond-mat/1/au:+AlloulH/0/1/0/all/0/1, H. Alloul; http://arxiv.org/find/cond-mat/1

  11. K+ and Na+ absorption by outer sulcus epithelial cells.

    PubMed

    Marcus, D C; Chiba, T

    1999-08-01

    Transduction of sound into nerve impulses by hair cells depends on modulation of a current carried primarily by K+ into the cell across apical transduction channels that are permeable to cations. The cochlear function thus depends on active secretion of K+ accompanied by absorption of Na+ by epithelial cells enclosing the cochlear duct. The para-sensory cells which participate in the absorption of Na+ (down to the uniquely low level of 1 mM) were previously unidentified and the existence of a para-sensory pathway which actively absorbs K+ was previously unknown. A relative short circuit current (Isc,probe, measured as the extracellular current density with a vibrating electrode) was directed into the apical side of the outer sulcus epithelium, decreased by ouabain (1 mM), an inhibitor of Na+, K(+)-ATPase, and found to depend on bath Na+ and K+ but on neither Ca2+ nor Cl-. Isc,probe was shown to be an active current by its sensitivity to ouabain. On-cell patch clamp recordings of the apical membrane of outer sulcus cells displayed a channel activity, which carried inward currents under conditions identical to those used to measure Isc,probe. Both Isc,probe and non-selective cation channels (27.4+/-0.6 ps, n = 22) in excised outside-out patches from the apical membrane were inhibited by Gd3+ (1 mM). Ics,prob was also inhibited by 5 mM lidocaine, 1 mM quinine and 500 microM amiloride but not by 10 microM amiloride. These results demonstrate that outer sulcus epithelial cells contribute to the homeostasis of endolymph by actively absorbing Na+ and K+. An entry pathway in the apical membrane was shown to be through non-selective cation channels that were sensitive to Gd3+.

  12. Na+-independent phosphate transport in Caco2BBE cells

    PubMed Central

    Candeal, Eduardo; Caldas, Yupanqui A.; Guillén, Natalia; Levi, Moshe

    2014-01-01

    Pi transport in epithelia has both Na+-dependent and Na+-independent components, but so far only Na+-dependent transporters have been characterized in detail and molecularly identified. Consequently, in the present study, we initiated the characterization and analysis of intestinal Na+-independent Pi transport using an in vitro model, Caco2BBE cells. Only Na+-independent Pi uptake was observed in these cells, and Pi uptake was dramatically increased when cells were incubated in high-Pi DMEM (4 mM) from 1 day to several days. No response to low-Pi medium was observed. The increased Pi transport was mainly caused by Vmax changes, and it was prevented by actinomycin D and cycloheximide. Pi transport in cells grown in 1 mM Pi (basal DMEM) decreased at pH > 7.5, and it was inhibited with proton ionophores. Pi transport in cells incubated with 4 mM Pi increased with alkaline pH, suggesting a preference for divalent phosphate. Pi uptake in cells in 1 mM Pi was completely inhibited only by Pi and partially inhibited by phosphonoformate, oxalate, DIDS, SITS, SO42−, HCO3−, and arsenate. This inhibition pattern suggests that more than one Pi transporter is active in cells maintained with 1 mM Pi. Phosphate transport from cells maintained at 4 mM Pi was only partially inhibited by phosphonoformate, oxalate, and arsenate. Attempts to identify the responsible transporters showed that multifunctional anion exchangers of the Slc26 family as well as members of Slc17, Slc20, and Slc37 and the Pi exporter xenotropic and polytropic retrovirus receptor 1 are not involved. PMID:25298422

  13. Na+-independent phosphate transport in Caco2BBE cells.

    PubMed

    Candeal, Eduardo; Caldas, Yupanqui A; Guillén, Natalia; Levi, Moshe; Sorribas, Víctor

    2014-12-15

    Pi transport in epithelia has both Na(+)-dependent and Na(+)-independent components, but so far only Na(+)-dependent transporters have been characterized in detail and molecularly identified. Consequently, in the present study, we initiated the characterization and analysis of intestinal Na(+)-independent Pi transport using an in vitro model, Caco2BBE cells. Only Na(+)-independent Pi uptake was observed in these cells, and Pi uptake was dramatically increased when cells were incubated in high-Pi DMEM (4 mM) from 1 day to several days. No response to low-Pi medium was observed. The increased Pi transport was mainly caused by Vmax changes, and it was prevented by actinomycin D and cycloheximide. Pi transport in cells grown in 1 mM Pi (basal DMEM) decreased at pH > 7.5, and it was inhibited with proton ionophores. Pi transport in cells incubated with 4 mM Pi increased with alkaline pH, suggesting a preference for divalent phosphate. Pi uptake in cells in 1 mM Pi was completely inhibited only by Pi and partially inhibited by phosphonoformate, oxalate, DIDS, SITS, SO4 (2-), HCO3 (-), and arsenate. This inhibition pattern suggests that more than one Pi transporter is active in cells maintained with 1 mM Pi. Phosphate transport from cells maintained at 4 mM Pi was only partially inhibited by phosphonoformate, oxalate, and arsenate. Attempts to identify the responsible transporters showed that multifunctional anion exchangers of the Slc26 family as well as members of Slc17, Slc20, and Slc37 and the Pi exporter xenotropic and polytropic retrovirus receptor 1 are not involved.

  14. Semi-volatiles at Mercury: Sodium (Na) and potassium (K)

    NASA Technical Reports Server (NTRS)

    Sprague, A.

    1994-01-01

    Several lines of evidence now suggest that Mercury is a planet rich in moderately-volatile elements such as Na and K. Recent mid-infrared spectral observations of Mercury's equatorial and mid-latitude region near 120 degrees mercurian longitude indicate the presence of plagioclase feldspar. Spectra of Mercury's surface exhibit spectral activity similar to labradorite (plagioclase feldspar with NaAlSi3O8: 30-50 percent) and bytownite (NaAlSi3O8: 10-30 percent). These surface studies were stimulated by the relatively large abundance of Na and K observed in Mercury's atmosphere. An enhanced column of K is observed at the longitudes of Caloris Basin and of the antipodal terrain. Extreme heating at these 'hot' longitudes and severe fracturing suffered from the large impact event could lead to enhanced outgassing from surface or subsurface materials. Alternatively, sputtering from a surface enriched in K could be the source of the observed enhancement. Recent microwave measurements of Mercury also give indirect evidence of a mercurian regolith less FeO-rich than the Moon. An anomalously high index of refraction derived from the whole-disk integrated phase curve of Danjon may also be indicative of surface sulfides contributing to a regolith that is moderately volatile-rich. The recent exciting observations of radar-bright spots at high latitudes also indicate that a substance of high volume scattering, like ice, is present in shadowed regions. Other radar-bright spots have been seen at locations of Na enhancements on the atmosphere. All combined, these pieces of evidence point to a planet that is not severely depleted in volatiles or semi-volatiles.

  15. Indirect activation of the epithelial Na+ channel by trypsin.

    PubMed

    Bengrine, Abderrahmane; Li, Jinqing; Hamm, L Lee; Awayda, Mouhamed S

    2007-09-14

    We tested the hypothesis that the serine protease trypsin can indirectly activate the epithelial Na(+) channel (ENaC). Experiments were carried out in Xenopus oocytes and examined the effects on the channel formed by all three human ENaC subunits and that formed by Xenopus epsilon and human beta and gamma subunits (epsilonbetagammaENaC). Low levels of trypsin (1-10 ng/ml) were without effects on the oocyte endogenous conductances and were specifically used to test the effects on ENaC. Addition of 1 ng/ml trypsin for 60 min stimulated the amiloride-sensitive human ENaC conductance (g(Na)) by approximately 6-fold. This effect on the g(Na) was [Na(+)]-independent, thereby ruling out an interaction with channel feedback inhibition by Na(+). The indirect nature of this activation was confirmed in cell-attached patch clamp experiments with trypsin added to the outside of the pipette. Trypsin was comparatively ineffective at activating epsilonbetagammaENaC, a channel that exhibited a high spontaneous open probability. These observations, in combination with surface binding experiments, indicated that trypsin indirectly activated membrane-resident channels. Activation by trypsin was also dependent on catalytic activity of this protease but was not accompanied by channel subunit proteolysis. Channel activation was dependent on downstream activation of G-proteins and was blocked by G-protein inhibition by injection of guanyl-5'-yl thiophosphate and by pre-stimulation of phospholipase C. These data indicate a receptor-mediated activation of ENaC by trypsin. This trypsin-activated receptor is distinct from that of protease-activated receptor-2, because the response to trypsin was unaffected by protease-activated receptor-2 overexpression or knockdown. PMID:17627947

  16. Preparation and visible light induced photocatalytic activity of C-NaTaO3 and C-NaTaO3-Cl-TiO2 composite.

    PubMed

    Wu, Xiaoyong; Yin, Shu; Dong, Qiang; Sato, Tsugio

    2013-12-21

    A nice visible light responsive C-doped NaTaO3 (C-NaTaO3) particle has been successfully prepared by a facile solvothermal method using water-ethylene glycol mixed solutions as solvent. The results presented that the carbon could be easily incorporated in NaTaO3 from ethylene glycol during a solvothermal reaction, finally leading to excellent visible light absorption. The as-synthesized C-NaTaO3 showed excellent visible light induced photocatalytic activity superior to those of pure NaTaO3 and commercial P25. In addition, in order to further improve the visible light driven photocatalytic performance of C-NaTaO3, a new C-doped NaTaO3-Cl-doped TiO2 (C-NaTaO3-Cl-TiO2) core-shell type of composite was also fabricated. After coupling C-NaTaO3 with Cl-TiO2, the visible light induced NOx gas destruction ability of C-NaTaO3-Cl-TiO2 composite was significantly enhanced as compared to those of sole C-NaTaO3 and Cl-TiO2, probably due to the hindrance of the recombination rate of photogenerated electron-hole pairs. The C-NaTaO3 particle and C-NaTaO3-Cl-TiO2 composite prepared in this work would probably provide a new way to prepare high performance of visible light induced perovskite-type NaTaO3 based photocatalysts.

  17. Effects of Ouabain on Proliferation of Human Endothelial Cells Correlate with Na+,K+-ATPase Activity and Intracellular Ratio of Na+ and K.

    PubMed

    Tverskoi, A M; Sidorenko, S V; Klimanova, E A; Akimova, O A; Smolyaninova, L V; Lopina, O D; Orlov, S N

    2016-08-01

    Side-by-side with inhibition of the Na+,K+-ATPase ouabain and other cardiotonic steroids (CTS) can affect cell functions by mechanisms other than regulation of the intracellular Na+ and K+ ratio ([Na+]i/[K+]i). Thus, we compared the dose- and time-dependences of the effect of ouabain on intracellular [Na+]i/[K+]i ratio, Na+,K+-ATPase activity, and proliferation of human umbilical vein endothelial cells (HUVEC). Treatment of the cells with 1-3 nM ouabain for 24-72 h decreased the [Na+]i/[K+]i ratio and increased cell proliferation by 20-50%. We discovered that the same ouabain concentrations increased Na+,K+-ATPase activity by 25-30%, as measured by the rate of (86)Rb(+) influx. Higher ouabain concentrations inhibited Na+,K+-ATPase, increased [Na+]i/[K+]i ratio, suppressed cell growth, and caused cell death. When cells were treated with low ouabain concentrations for 48 or 72 h, a negative correlation between [Na+]i/[K+]i ratio and cell growth activation was observed. In cells treated with high ouabain concentrations for 24 h, the [Na+]i/[K+]i ratio correlated positively with proliferation inhibition. These data demonstrate that inhibition of HUVEC proliferation at high CTS concentrations correlates with dissipation of the Na+ and K+ concentration gradients, whereas cell growth stimulation by low CTS doses results from activation of Na+,K+-ATPase and decrease in the [Na+]i/[K+]i ratio. PMID:27677555

  18. Light-driven Na(+) pump from Gillisia limnaea: a high-affinity Na(+) binding site is formed transiently in the photocycle.

    PubMed

    Balashov, Sergei P; Imasheva, Eleonora S; Dioumaev, Andrei K; Wang, Jennifer M; Jung, Kwang-Hwan; Lanyi, Janos K

    2014-12-01

    A group of microbial retinal proteins most closely related to the proton pump xanthorhodopsin has a novel sequence motif and a novel function. Instead of, or in addition to, proton transport, they perform light-driven sodium ion transport, as reported for one representative of this group (KR2) from Krokinobacter. In this paper, we examine a similar protein, GLR from Gillisia limnaea, expressed in Escherichia coli, which shares some properties with KR2 but transports only Na(+). The absorption spectrum of GLR is insensitive to Na(+) at concentrations of ≤3 M. However, very low concentrations of Na(+) cause profound differences in the decay and rise time of photocycle intermediates, consistent with a switch from a "Na(+)-independent" to a "Na(+)-dependent" photocycle (or photocycle branch) at ∼60 μM Na(+). The rates of photocycle steps in the latter, but not the former, are linearly dependent on Na(+) concentration. This suggests that a high-affinity Na(+) binding site is created transiently after photoexcitation, and entry of Na(+) from the bulk to this site redirects the course of events in the remainder of the cycle. A greater concentration of Na(+) is needed for switching the reaction path at lower pH. The data suggest therefore competition between H(+) and Na(+) to determine the two alternative pathways. The idea that a Na(+) binding site can be created at the Schiff base counterion is supported by the finding that upon perturbation of this region in the D251E mutant, Na(+) binds without photoexcitation. Binding of Na(+) to the mutant shifts the chromophore maximum to the red like that of H(+), which occurs in the photocycle of the wild type.

  19. Apical membrane Na+/H+ exchange in Necturus gallbladder epithelium. Its dependence on extracellular and intracellular pH and on external Na+ concentration

    PubMed Central

    1990-01-01

    Intracellular microelectrode techniques and extracellular pH measurements were used to study the dependence of apical Na+/H+ exchange on mucosal and intracellular pH and on mucosal solution Na+ concentration ([Na+]o). When mucosal solution pH (pHo) was decreased in gallbladders bathed in Na(+)-containing solutions, aNai fell. The effect of pHo is consistent with titration of a single site with an apparent pK of 6.29. In Na(+)-depleted tissues, increasing [Na+]o from 0 to values ranging from 2.5 to 110 mM increased aNai; the relationship was well described by Michaelis-Menten kinetics. The apparent Km was 15 mM at pHo 7.5 and increased to 134 mM at pHo 6.5, without change in Vmax. In Na(+)-depleted gallbladders, elevating [Na+]o from 0 to 25 mM increased aNai and pHi and caused acidification of a poorly buffered mucosal solution upon stopping the superfusion; lowering pHo inhibited both apical Na+ entry and mucosal solution acidification. Both effects can be ascribed to titration of a single site; the apparent pK's were 7.2 and 7.4, respectively. Diethylpyrocarbonate (DEPC), a histidine- specific reagent, reduced mucosal acidification by 58 +/- 4 or 39 +/- 6% when exposure to the drug was at pHo 7.5 or 6.5, respectively. Amiloride (1 mM) did not protect against the DEPC inhibition, but reduced both apical Na+ entry and mucosal acidification by 63 +/- 5 and 65 +/- 9%, respectively. In the Na(+)-depleted tissues mean pHi was 6.7. Cells were alkalinized by exposure to mucosal solutions containing high concentrations of nicotine or methylamine. Estimates of apical Na+ entry at varying pHi, upon increasing [Na+]o from 0 to 25 mM, indicate that Na+/H+ exchange is active at pHi 7.4. Intracellular H+ stimulated apical Na+ entry by titration of more than one site (apparent pK 7.1, Hill coefficient 1.7). The results suggest that external Na+ and H+ interact with one site of the Na+/H+ exchanger and that cytoplasmic H+ acts on at least two sites. The external titratable group

  20. Interfacial electronic structure of Na deposited on rubrene thin film studied by synchrotron radiation photoemission

    NASA Astrophysics Data System (ADS)

    Wei, Ching-Hsuan; Cheng, Chiu-Ping; Lin, Hong-Cheu; Pi, Tun-Wen

    2015-12-01

    The electronic structure of rubrene doped with various concentrations of Na was studied by synchrotron-radiation photoemission. Three stages of development were found with increasing Na concentration; Na penetrating deep into the organic film, followed by development of gap states, and ended with a metallic Na film. The charge transfer from Na to rubrene resulted in a vacuum-level shift. By doping Na into rubrene, we could control the IP of the organic molecule, which is favorable for application in organic semiconductor devices.

  1. Na sup + pump in renal tubular cells is regulated by endogenous Na sup + -K sup + -ATPase inhibitor from hypothalamus

    SciTech Connect

    Cantiello, H.F.; Chen, E.; Ray, S.; Haupert, G.T. Jr. )

    1988-10-01

    Bovine hypothalamus contains a high affinity, specific, reversible inhibitor of mammalian Na{sup +}-K{sup +}-ATPase. Kinetic analysis using isolated membrane fractions showed binding and dissociation rates of the hypothalamic factor (HF) to be (like ouabain) relatively long (off rate = 60 min). To determine whether the kinetics of inhibition in intact cells might be more consistent with regulation of physiological processes in vivo, binding and dissociation reactions of HF in intact renal epithelial cells (LLC-PK{sup 1}) were studied using {sup 86}Rb{sup +} uptake and ({sup 3}H)ouabain binding. As with membranes, a 60-min incubation with HF inhibited Na{sup +}-K{sup +}-ATPase in LLC-PK{sub 1} cells. In contrast to membrane studies, no prolonged incubation with LLC-PK{sub 1} was needed to observe inhibition of Na{sup +}-K{sup +}-ATPase. HF caused a 33% inhibition of ouabain-sensitive {sup 86}Rb{sup +} influx within 10 min. Incubation of cells with HF followed by washout showed rapid reversal of pump inhibition and a doubling of pump activity. The dose-response curve for HF inhibition of LLC-PK{sub 1} {sup 86}Rb{sup +} uptake showed a sigmoidal shape consistent with an allosteric binding reaction. Thus HF is a potent regulator of Na{sup +}-K{sup +}-ATPase activity in intact renal cells, with binding and dissociation reactions consistent with relevant physiological processes.

  2. Genetic Variation of the Alpha Subunit of the Epithelial Na+ Channels Influences Exhaled Na+ in Healthy Humans

    PubMed Central

    Foxx-Lupo, William T.; Wheatley, Courtney M.; Baker, Sarah E.; Cassuto, Nicholas A.; Delamere, Nicholas A.; Snyder, Eric M.

    2011-01-01

    Epithelial Na+ Channels (ENaC) are located on alveolar cells and are important in β2-adrenergic receptor-mediated lung fluid clearance through the removal of Na+ from the alveolar airspace. Previous work has demonstrated that genetic variation of the alpha subunit of ENaC at amino acid 663 is important in channel function: cells with the genotype resulting in alanine at amino acid 663 (A663) demonstrate attenuated function when compared to genotypes with at least one allele encoding threonine (T663, AT/TT). We sought to determine the influence of genetic variation at position 663 of ENaC on exhaled Na+ in healthy humans. Exhaled Na+ was measured in 18 AA and 13 AT/TT subjects (age=27±8 vs. 30±10yrs., ht.=174±12 vs. 171±10cm., wt=68±12 vs. 73±14kg., BMI=22±3 vs. 25±4kg/m2, mean±SD, for AA and AT/TT, respectively). Measurements were made at baseline and at 30, 60 and 90 minutes following the administration of a nebulized β2-agonist (albuterol sulfate, 2.5mg diluted in 3ml normal saline). The AA group had a higher baseline level of exhaled Na+ and a greater response to β2-agonist stimulation (baseline= 3.1±1.8 vs. 2.3±1.5mmol/l; 30min-post= 2.1±0.7 vs. 2.2±0.8mmol/l; 60min-post= 2.0±0.5 vs. 2.3±1.0mmol/l; 90min-post= 1.8±0.8 vs. 2.6±1.5mmol/l, mean±SD, for AA and AT/TT, respectively, p<0.05). The results are consistent with the notion that genetic variation of ENaC influences β2-adrenergic receptor stimulated Na+ clearance in the lungs, as there was a significant reduction in exhaled Na+ over time in the AA group. PMID:21889619

  3. Cytoplasmic Na+-dependent modulation of mitochondrial Ca2+ via electrogenic mitochondrial Na+–Ca2+ exchange

    PubMed Central

    Kim, Bongju; Matsuoka, Satoshi

    2008-01-01

    To clarify the role of mitochondrial Na+–Ca2+ exchange (NCXmito) in regulating mitochondrial Ca2+ (Ca2+mito) concentration at intact and depolarized mitochondrial membrane potential (ΔΨmito), we measured Ca2+mito and ΔΨmito using fluorescence probes Rhod-2 and TMRE, respectively, in the permeabilized rat ventricular cells. Applying 300 nm cytoplasmic Ca2+ (Ca2+c) increased Ca2+mito and this increase was attenuated by cytoplasmic Na+ (Na+c) with an IC50 of 2.4 mm. To the contrary, when ΔΨmito was depolarized by FCCP, a mitochondrial uncoupler, Na+c enhanced the Ca2+c-induced increase in Ca2+mito with an EC50 of about 4 mm. This increase was not significantly affected by ruthenium red or cyclosporin A. The inhibition of NCXmito by CGP-37157 further increased Ca2+mito when ΔΨmito was intact, while it suppressed the Ca2+mito increase when ΔΨmito was depolarized, suggesting that ΔΨmito depolarization changed the exchange mode from forward to reverse. Furthermore, ΔΨmito depolarization significantly reduced the Ca2+mito decrease via forward mode, and augmented the Ca2+mito increase via reverse mode. When the respiratory chain was attenuated, the induction of the reverse mode of NCXmito hyperpolarized ΔΨmito, while ΔΨmito depolarized upon inducing the forward mode of NCXmito. Both changes in ΔΨmito were remarkably inhibited by CGP-37157. The above experimental data indicated that NCXmito is voltage dependent and electrogenic. This notion was supported theoretically by computer simulation studies with an NCXmito model constructed based on present and previous studies, presuming a consecutive and electrogenic Na+–Ca2+ exchange and a depolarization-induced increase in Na+ flux. It is concluded that Ca2+mito concentration is dynamically modulated by Na+c and ΔΨmito via electrogenic NCXmito. PMID:18218682

  4. INTEX-NA: Intercontinental Chemical Transport Experiment - North America

    NASA Technical Reports Server (NTRS)

    Singh, Hanwant B.; Jacob, D.; Pfister, L.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    INTEX-NA is an integrated atmospheric chemistry field experiment to be performed over North America using the NASA DC-8 and P-3B aircraft as its primary platforms. It seeks to understand the exchange of chemicals and aerosols between continents and the global troposphere. The constituents of interest are ozone and its precursors (hydrocarbons, NOX and HOX), aerosols, and the major greenhouse gases (CO2, CH4, N2O). INTEX-NA will provide the observational database needed to quantify inflow, outflow, and transformations of chemicals over North America. INTEX-NA is to be performed in two phases. Phase A will take place during the period of May-August 2004 and Phase B during March-June 2006. Phase A is in summer when photochemistry is most intense and climatic issues involving aerosols and carbon cycle are most pressing, and Phase B is in spring when Asian transport to North America is at its peak. INTEX-NA will coordinate its activities with concurrent measurement programs including satellites (e. g. Terra, Aura, Envisat), field activities undertaken by the North American Carbon Program (NACP), and other U.S. and international partners. However, it is being designed as a 'stand alone' mission such that its successful execution is not contingent on other programs. Synthesis of the ensemble of observation from surface, airborne, and space platforms, with the help of global/regional models is an important It is anticipated that approximately 175 flight hours for each of the aircraft (DC-8 and P-3B) will be required for each Phase. Principal operational sites are tentatively selected to be Bangor, ME; Wallops Island, VA; Seattle, WA; Rhinelander, WI; Lancaster, CA; and New Orleans, LA. These coastal and continental sites can support large missions and are suitable for INTEX-NA objectives. The experiment will be supported by forecasts from meteorological and chemical models, satellite observations, surface networks, and enhanced O3,-sonde releases. In addition to

  5. Analysis of cardiovascular responses to the H2S donors Na2S and NaHS in the rat

    PubMed Central

    Yoo, Daniel; Jupiter, Ryan C.; Pankey, Edward A.; Reddy, Vishwaradh G.; Edward, Justin A.; Swan, Kevin W.; Peak, Taylor C.; Mostany, Ricardo

    2015-01-01

    Hydrogen sulfide (H2S) is an endogenous gaseous molecule formed from L-cysteine in vascular tissue. In the present study, cardiovascular responses to the H2S donors Na2S and NaHS were investigated in the anesthetized rat. The intravenous injections of Na2S and NaHS 0.03–0.5 mg/kg produced dose-related decreases in systemic arterial pressure and heart rate, and at higher doses decreases in cardiac output, pulmonary arterial pressure, and systemic vascular resistance. H2S infusion studies show that decreases in systemic arterial pressure, heart rate, cardiac output, and systemic vascular resistance are well-maintained, and responses to Na2S are reversible. Decreases in heart rate were not blocked by atropine, suggesting that the bradycardia was independent of parasympathetic activation and was mediated by an effect on the sinus node. The decreases in systemic arterial pressure were not attenuated by hexamethonium, glybenclamide, Nw-nitro-l-arginine methyl ester hydrochloride, sodium meclofenamate, ODQ, miconazole, 5-hydroxydecanoate, or tetraethylammonium, suggesting that ATP-sensitive potassium channels, nitric oxide, arachidonic acid metabolites, cyclic GMP, p450 epoxygenase metabolites, or large conductance calcium-activated potassium channels are not involved in mediating hypotensive responses to the H2S donors in the rat and that responses are not centrally mediated. The present data indicate that decreases in systemic arterial pressure in response to the H2S donors can be mediated by decreases in vascular resistance and cardiac output and that the donors have an effect on the sinus node independent of the parasympathetic system. The present data indicate that the mechanism of the peripherally mediated hypotensive response to the H2S donors is uncertain in the intact rat. PMID:26071540

  6. Increased vacuolar Na(+)/H(+) exchange activity in Salicornia bigelovii Torr. in response to NaCl.

    PubMed

    Parks, Graham E; Dietrich, Margaret A; Schumaker, Karen S

    2002-05-01

    Shoots of the halophyte Salicornia bigelovii are larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. In glycophytes, sensitivity to salt has been associated with an inability to remove sodium ions effectively from the cytoplasm in order to protect salt-sensitive metabolic processes. Therefore, in Salicornia bigelovii efficient vacuolar sequestration of sodium may be part of the mechanism underlying salt tolerance. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole via a Na(+)/H(+) exchanger. In current studies, increased vacuolar pyrophosphatase activity (hydrolysis of inorganic pyrophosphate and proton translocation) and protein accumulation were observed in Salicornia bigelovii grown in high concentrations of NaCl. Based on sodium-induced dissipation of a pyrophosphate-dependent pH gradient in vacuolar membrane vesicles, a Na(+)/H(+) exchange activity was identified and characterized. This activity is sodium concentration-dependent, specific for sodium and lithium, sensitive to methyl-isobutyl amiloride, and independent of an electrical potential. Vacuolar Na(+)/H(+) exchange activity varied as a function of plant growth in salt. The affinity of the transporter for Na(+) is almost three times higher in plants grown in high levels of salt (K(m)=3.8 and 11.5 mM for plants grown in high and low salt, respectively) suggesting a role for exchange activity in the salt adaptation of Salicornia bigelovii. PMID:11971917

  7. Two independent evolutionary routes to Na+/H+ cotransport function in membrane pyrophosphatases.

    PubMed

    Nordbo, Erika; Luoto, Heidi H; Baykov, Alexander A; Lahti, Reijo; Malinen, Anssi M

    2016-10-01

    Membrane-bound pyrophosphatases (mPPases) hydrolyze pyrophosphate (PPi) to transport H(+), Na(+) or both and help organisms to cope with stress conditions, such as high salinity or limiting nutrients. Recent elucidation of mPPase structure and identification of subfamilies that have fully or partially switched from Na(+) to H(+) pumping have established mPPases as versatile models for studying the principles governing the mechanism, specificity and evolution of cation transporters. In the present study, we constructed an accurate phylogenetic map of the interface of Na(+)-transporting PPases (Na(+)-PPases) and Na(+)- and H(+)-transporting PPases (Na(+),H(+)-PPases), which guided our experimental exploration of the variations in PPi hydrolysis and ion transport activities during evolution. Surprisingly, we identified two mPPase lineages that independently acquired physiologically significant Na(+) and H(+) cotransport function. Na(+),H(+)-PPases of the first lineage transport H(+) over an extended [Na(+)] range, but progressively lose H(+) transport efficiency at high [Na(+)]. In contrast, H(+)-transport by Na(+),H(+)-PPases of the second lineage is not inhibited by up to 100 mM Na(+) With the identification of Na(+),H(+)-PPase subtypes, the mPPases protein superfamily appears as a continuum, ranging from monospecific Na(+) transporters to transporters with tunable levels of Na(+) and H(+) cotransport and further to monospecific H(+) transporters. Our results lend credence to the concept that Na(+) and H(+) are transported by similar mechanisms, allowing the relative efficiencies of Na(+) and H(+) transport to be modulated by minor changes in protein structure during the course of adaptation to a changing environment.

  8. Investigation of sodium distribution in phosphate glasses using spin-echo {sup 23}Na NMR

    SciTech Connect

    Alam, T.M.; McLaughlin, J.; Click, C.C.; Conzone, S.; Brow, R.K.; Boyle, T.J.; Zwanziger, J.W.

    2000-02-24

    The spatial arrangements of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O{sm{underscore}bullet}(100{minus}x)P{sub 2}O{sub 5} (x {le} 55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling, and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases nonlinearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model, and a pairwise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS models, it is demonstrated that the slight nonlinear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and nonclustered distributions becomes more difficult at higher sodium concentrations.

  9. Investigation of Sodium Distribution in Phosphate Glasses Using Spin-Echo {sup 23}Na NMR

    SciTech Connect

    ALAM, TODD M.; BOYLE, TIMOTHY J.; BROW, RICHARD K.; CLICK, CAROL C.; CONZONE, SAM; McLAUGHLIN, JAY; ZWANZIGER, JOE

    1999-09-16

    The spatial arrangement of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O(100-x)P{sub 2}O{sub 5} (x<55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases non-linearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model and a pair-wise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS model, it is demonstrated that the slight non-linear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and non-clustered distributions becomes more difficult at higher sodium concentrations.

  10. Validation of estimating food intake in gray wolves by 22Na turnover

    USGS Publications Warehouse

    DelGiudice, G.D.; Duquette, L.S.; Seal, U.S.; Mech, L.D.

    1991-01-01

    We studied 22sodium (22Na) turnover as a means of estimating food intake in 6 captive, adult gray wolves (Canis lupus) (2 F, 4 M) over a 31-day feeding period. Wolves were fed white-tailed deer (Odocoileus virginianus) meat only. Mean mass-specific exchangeable Na pool was 44.8 .+-. 0.7 mEq/kg; there was no differeence between males and females. Total exchangeable Na was related (r2 = 0.85, P < 0.009) to body mass. Overall, 22Na turnover overestimated Na intake by 9.8 .+-. 2.4% after 32 days. Actual Na intake was similar in males and females; however, Na turnover (P < 0.05) and the discrepancy (P < 0.01) between turnover and actual Na intake were greater in females than males. From Day 8 to the end of the study, the absolute difference (mEq) between Na intake and Na turnover remained stable. Sodium turnover (mEq/kg/day) was a reliable (r2 = 0.91, P < 0.001) estimator of food consumption (g/kg/day) in wolves over a 32-day period. Sampling blood and weighing wolves every 1-4 days permitted identification of several potential sources of error, including changes in size of exchangeable Na pools, exchange of 22Na with gastrointestinal and bone Na, and rapid loss of the isotope by urinary excretion.

  11. Effect of NaCl and Na2SO4 on the biodecolourization of K-2BP by Halomonas sp. GYW

    PubMed Central

    Lian, Jing; Xu, Zhifang; Guo, Jianbo; Yue, Lin; Guo, Yankai; Zhang, Chenxiao; Yang, Jingliang

    2014-01-01

    In this paper, the effect of NaCl and Na2SO4 on the biodecolourization of reactive brilliant red K-2BP by a Halomonas sp. GYW (EF188281) was investigated in details. The decolourisation efficiency and the oxidation–reduction potential (ORP) change were explored during the decolourization process. The results from sequencing batch tests showed that Na2SO4 influenced the decolourization efficiency more slightly than NaCl in different synthetic dye solutions with different mixtures of Na2SO4 and NaCl. In the dye solutions with the same salt concentration or the same Na+ concentration, high Na2SO4 concentration did not inhibit the decolourization process and even stimulated the decolourization efficiency of reactive brilliant red K-2BP. Compared to NaCl system, the addition of Na2SO4 increased the ORP values about 35 mV, which agreed with the theoretic analysis of Gibbs function. This study improved our knowledge of azo dye decolourization under high salinity conditions and provided efficient option for the treatment of azo dye wastewater. PMID:27594796

  12. Heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(s)

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun; Timonen, Raimo S.; Keyser, Leon F.; Yung, Yuk L.

    1995-01-01

    The heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(S) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(exp -8) - 2 x 10(exp -6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1sigma) at 296 K and > 0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(exp -4) at both 223 and 296 K. The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) yields 2HNO3(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.

  13. "Oxygen Sensing" by Na,K-ATPase: These Miraculous Thiols.

    PubMed

    Bogdanova, Anna; Petrushanko, Irina Y; Hernansanz-Agustín, Pablo; Martínez-Ruiz, Antonio

    2016-01-01

    Control over the Na,K-ATPase function plays a central role in adaptation of the organisms to hypoxic and anoxic conditions. As the enzyme itself does not possess O2 binding sites its "oxygen-sensitivity" is mediated by a variety of redox-sensitive modifications including S-glutathionylation, S-nitrosylation, and redox-sensitive phosphorylation. This is an overview of the current knowledge on the plethora of molecular mechanisms tuning the activity of the ATP-consuming Na,K-ATPase to the cellular metabolic activity. Recent findings suggest that oxygen-derived free radicals and H2O2, NO, and oxidized glutathione are the signaling messengers that make the Na,K-ATPase "oxygen-sensitive." This very ancient signaling pathway targeting thiols of all three subunits of the Na,K-ATPase as well as redox-sensitive kinases sustains the enzyme activity at the "optimal" level avoiding terminal ATP depletion and maintaining the transmembrane ion gradients in cells of anoxia-tolerant species. We acknowledge the complexity of the underlying processes as we characterize the sources of reactive oxygen and nitrogen species production in hypoxic cells, and identify their targets, the reactive thiol groups which, upon modification, impact the enzyme activity. Structured accordingly, this review presents a summary on (i) the sources of free radical production in hypoxic cells, (ii) localization of regulatory thiols within the Na,K-ATPase and the role reversible thiol modifications play in responses of the enzyme to a variety of stimuli (hypoxia, receptors' activation) (iii) redox-sensitive regulatory phosphorylation, and (iv) the role of fine modulation of the Na,K-ATPase function in survival success under hypoxic conditions. The co-authors attempted to cover all the contradictions and standing hypotheses in the field and propose the possible future developments in this dynamic area of research, the importance of which is hard to overestimate. Better understanding of the processes

  14. Fusion of Na-ASP-2 with human immunoglobulin Fcγ abrogates histamine release from basophils sensitized with anti-Na-ASP-2 IgE.

    PubMed

    Zhan, Bin; Santiago, H; Keegan, B; Gillespie, P; Xue, J; Bethony, J; de Oliveira, L M; Jiang, D; Diemert, D; Xiao, S-H; Jones, K; Feng, X; Hotez, P J; Bottazzi, M E

    2012-01-01

    Na-ASP-2 is a major protein secreted by infective third-stage larvae (L3) of the human hookworm Necator americanus upon host entry. It was chosen as a lead vaccine candidate for its ability to elicit protective immune responses. However, clinical development of this antigen as a recombinant vaccine was halted because it caused allergic reactions among some of human volunteers previously infected with N. americanus. To prevent IgE-mediated allergic reactions induced by Na-ASP-2 but keep its immunogenicity as a vaccine antigen, we designed and tested a genetically engineered fusion protein, Fcγ/Na-ASP-2, composed of full-length Na-ASP-2 and truncated human IgG Fcγ1 that targets the negative signalling receptor FcγRIIb expressed on pro-allergic cells. The chimeric recombinant Fcγ/Na-ASP-2 protein was expressed in Pichia pastoris and shared the similar antigenicity as native Na-ASP-2. Compared to Na-ASP-2, the chimeric fusion protein efficiently reduced the release of histamine in human basophils sensitized with anti-Na-ASP-2 IgE obtained from individuals living in a hookworm-endemic area. In dogs infected with canine hookworm, Fcγ/Na-ASP-2 resulted in significantly reduced immediate-type skin reactivity when injected intradermally compared with Na-ASP-2. Hamsters vaccinated with Fcγ/Na-ASP-2 formulated with Alhydrogel(®) produced specific IgG that recognized Na-ASP-2 and elicited similar protection level against N. americanus L3 challenge as native Na-ASP-2.

  15. NaN, a novel voltage-gated Na channel, is expressed preferentially in peripheral sensory neurons and down-regulated after axotomy

    PubMed Central

    Dib-Hajj, S. D.; Tyrrell, L.; Black, J. A.; Waxman, S. G.

    1998-01-01

    Although physiological and pharmacological evidence suggests the presence of multiple tetrodotoxin-resistant (TTX-R) Na channels in neurons of peripheral nervous system ganglia, only one, SNS/PN3, has been identified in these cells to date. We have identified and sequenced a novel Na channel α-subunit (NaN), predicted to be TTX-R and voltage-gated, that is expressed preferentially in sensory neurons within dorsal root ganglia (DRG) and trigeminal ganglia. The predicted amino acid sequence of NaN can be aligned with the predicted structure of known Na channel α-subunits; all relevant landmark sequences, including positively charged S4 and pore-lining SS1–SS2 segments, and the inactivation tripeptide IFM, are present at predicted positions. However, NaN exhibits only 42–53% similarity to other mammalian Na channels, including SNS/PN3, indicating that it is a novel channel, and suggesting that it may represent a third subfamily of Na channels. NaN transcript levels are reduced significantly 7 days post axotomy in DRG neurons, consistent with previous findings of a reduction in TTX-R Na currents. The preferential expression of NaN in DRG and trigeminal ganglia and the reduction of NaN mRNA levels in DRG after axonal injury suggest that NaN, together with SNS/PN3, may produce TTX-R currents in peripheral sensory neurons and may influence the generation of electrical activity in these cells. PMID:9671787

  16. NaCl does not affect hypothalamic noradrenergic input in deoxycorticosterone acetate/NaCl and Dahl salt-sensitive rats.

    PubMed

    Chen, Y F; Meng, Q C; Wyss, J M; Jin, H K; Rogers, C F; Oparil, S

    1990-07-01

    Previous studies from our laboratories demonstrated that dietary NaCl supplementation in NaCl-sensitive spontaneously hypertensive rats elevates blood pressure, increases peripheral sympathetic nervous system activity, and depresses endogenous norepinephrine stores and turnover in the anterior hypothalamus. These findings suggest that reduced noradrenergic input to sympathoinhibitory neurons in anterior hypothalamus contributes to NaCl-sensitive hypertension in spontaneously hypertensive rats. The current study tested the hypothesis that dietary NaCl supplementation depresses endogenous norepinephrine stores and turnover in anterior hypothalamus of two other NaCl-sensitive models of hypertension, the Dahl salt-sensitive rat and the deoxycorticosterone acetate/NaCl hypertensive rat, thus increasing blood pressure by reducing noradrenergic input to the anterior hypothalamus. Dahl salt-sensitive rats were fed a high (8%) NaCl diet, and deoxycorticosterone acetate/NaCl rats rats drank 1% NaCl solution ad libitum for 2 or 4 weeks. Age-matched Dahl salt-sensitive rats fed a basal 1% NaCl diet and uninephrectomized Sprague-Dawley rats drinking tap water were controls. Regional brain catecholamines were determined by high-performance liquid chromatography with electrochemical detection. Norepinephrine turnover in hypothalamus (anterior, posterior, and ventral regions) and brain stem (pons and medulla) was assessed using the dopamine beta-hydroxylase inhibitor 1-cyclohexyl-2-mercapto-imidazole. High NaCl treatment caused significant elevations in blood pressure in Dahl salt-sensitive and deoxycorticosterone acetate/NaCl rats, but endogenous norepinephrine levels and turnover rates were not significantly different in anterior hypothalamus or any other brain region studied between the NaCl-supplemented and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Sequential growth of sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell-shell nanoparticles for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Peng, Huang-Yong; Ding, Bin-Bin; Ma, Yin-Chu; Sun, Shi-Qi; Tao, Wei; Guo, Yan-Chuan; Guo, Hui-Chen; Yang, Xian-Zhu; Qian, Hai-Sheng

    2015-12-01

    Upconversion (UC) nanostructures have attracted much interest for their extensive biological applications. In this work, we describe a sequential synthetic route to prepare sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles. The as-prepared products were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM, JEM 2100F), respectively. The as-prepared core-shell nanoparticles of NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb are composed of elliptical nanoparticles with a length of 80 nm and width of 42 nm, which show efficient upconversion fluorescence excited at 808 nm indicating the formation of core-shell-shell sandwiched nanostructures. In addition, the as-prepared sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles also show strong upconversion fluorescence excited at 980 nm. Amphiphilic mPEG2k-b-PEBEP6K copolymers (denoted as PPE) were chosen to transfer these hydrophobic UCNPs into the aqueous phase for biological application. In vitro photodynamic therapy of cancer cells show that the viability of cells incubated with the nanoparticles loaded with MC 540 was significantly lower as compared to the nanoparticles without photosensitizers exposed to NIR laser.

  18. Synthesis and structures of type-I clathrates: Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Mu, Gang; Huang, Fuqiang; Xie, Xiaoming

    2016-10-01

    Type-I clathrates of Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38 were synthesized via solid-state reaction. Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38 were found to crystalize in the cubic space group of Pm 3 ̅ n with lattice parameters of a=10.72755(5) Å, a=10.79501(8) Å and a=10.79726(5) Å, respectively. Theoretical calculations indicated semiconducting features for the calculation models of Rb6Na2Ge44, Cs6Na2Zn4Ge42 and Cs6Na2Ga8Ge38 with band gaps of 0.002 eV, 0.297 eV and 0.221 eV, respectively.

  19. The influence of beta subunit structure on the interaction of Na+/K(+)-ATPase complexes with Na+. A chimeric beta subunit reduces the Na+ dependence of phosphoenzyme formation from ATP.

    PubMed

    Eakle, K A; Lyu, R M; Farley, R A

    1995-06-01

    High-affinity ouabain binding to Na+/K(+)-ATPase (sodium- and potassium-transport adenosine triphosphatase (EC 3.6.1.37)) requires phosphorylation of the alpha subunit of the enzyme either by ATP or by inorganic phosphate. For the native enzyme (alpha/beta 1), the ATP-dependent reaction proceeds about 4-fold more slowly in the absence of Na+ than when saturating concentrations of Na+ are present. Hybrid pumps were formed from either the alpha 1 or the alpha 3 subunit isoforms of Na+/K(+)-ATPase and a chimeric beta subunit containing the transmembrane segment of the Na+/K(+)-ATPase beta 1 isoform and the external domain of the gastric H+/K(+)-ATPase beta subunit (alpha/NH beta 1 complexes). In the absence of Na+, these complexes show a rate of ATP-dependent ouabain binding from approximately 75-100% of the rate seen in the presence of Na+ depending on buffer conditions. Nonhydrolyzable nucleotides or treatment of ATP with apyrase abolishes ouabain binding, demonstrating that ouabain binding to alpha/NH beta 1 complexes requires phosphorylation of the protein. Buffer ions inhibit ouabain binding by alpha/NH beta 1 in the absence of Na+ rather than promote ouabain binding, indicating that they are not substituting for sodium ions in the phosphorylation reaction. The pH dependence of ATP-dependent ouabain binding in the presence or absence of Na+ is similar, suggesting that protons are probably not substituting for Na+. Hybrid alpha/NH beta 1 pumps also show slightly higher apparent affinities (2-3-fold) for ATP, Na+, and ouabain; however, these are not sufficient to account for the increase in ouabain binding in the absence of Na+. In contrast to phosphoenzyme formation and ouabain binding by alpha/NH beta 1 complexes in the absence of Na+, ATPase activity, measured as release of phosphate from ATP, requires Na+. These data suggest that the transition from E1P to E2P during the catalytic cycle does not occur when the sodium binding sites are not occupied. Thus, the

  20. Na+ accumulation in root symplast of sunflower plants exposed to moderate salinity is transpiration-dependent.

    PubMed

    Quintero, José Manuel; Fournier, José María; Benlloch, Manuel; Rodríguez-Navarro, Alonso

    2008-08-25

    Twenty-day-old sunflower plants (Helianthus annuus L. cv Sun-Gro 380) grown hydroponically under controlled conditions were used to study the effect of transpiration on Na(+) compartmentalization in roots. The plants were exposed to low Na(+) concentrations (25 mM NaCl) and different environmental humidity conditions over a short time period (8.5 h). Under these conditions, Na(+) was accumulated primarily in the root, but only the Na(+) accumulated in the root symplast was dependent on transpiration, while the Na(+) accumulated in both the shoot and the root apoplast exhibited a low transpiration dependence. Moreover, Na(+) content in the root apoplast was reached quickly (0.25 h) and increased little with time. These results suggest that, in sunflower plants under moderate salinity conditions, Na(+) uptake in the root symplast is mediated by a transport system whose activity is enhanced by transpiration. PMID:18166246

  1. Synthesis of NaB5C bulk ceramics by reaction sintering

    NASA Astrophysics Data System (ADS)

    Morito, Haruhiko; Anzai, Jun; Kimura, Takuma; Yamane, Hisanori

    2015-09-01

    Bulk ceramics of NaB5C were prepared by heating compact bodies of amorphous boron (B) and carbon black (C) powders with Na at 1073 K. The obtained bulk ceramics retained the rectangular shape of their original compacts. The obtained samples had a density of 80.1 ± 0.6% of the theoretical density of NaB5C. NaB5C bulk ceramics were also prepared by heating compacts comprised of B and C powders and Na. The addition of Na to the starting compact bodies increased the relative bulk density to 83.5 ± 0.4%. A fracture bending strength of 195 MPa was measured for the NaB5C bulk sample prepared from the compact of Na, B, and C.

  2. Preferential Interaction of Na+ over K+ to Carboxylate-functionalized Silver Nanoparticles

    EPA Science Inventory

    Elucidating mechanistic interactions between specific ions (Na+/ K+) and nanoparticle surfaces to alter particle stability in polar media has received little attention. We investigated relative preferential binding of Na+ and K+ to carboxylate-functionalized silver nanoparticles ...

  3. The NA62 Liquid Krypton calorimeter readout architecture

    NASA Astrophysics Data System (ADS)

    Ceccucci, A.; Fantechi, R.; Farthouat, P.; Ryjov, V.; De Simone, N.; Venditti, S.

    2016-01-01

    The NA62 experiment [1] at the CERN SPS (Super Proton Synchrotron) accelerator studies the ultra-rare decays of charged kaons. The high-resolution Liquid Krypton (LKr) electromagnetic calorimeter of the former NA48 experiment [2] is a key component of the experiment photon-veto system. The new LKr readout system comprises 14,000 14-bit ADC acquisition channels, 432× 1 Gbit Ethernet data request and readout links routed by 28× 10 Gbit network switches to the experiment computer farm, and timing, trigger and control (TTC) distribution system. This paper presents the architecture of the LKr readout and TTC systems, the overall performance and the first successfully collected experiment physics data.

  4. Optically stimulated luminescence in doped NaF.

    PubMed

    Gaikwad, S U; Patil, R R; Kulkarni, M S; Bhatt, B C; Moharil, S V

    2016-05-01

    OSL in doped NaF is studied. Study shows that NaF:Mg,Cu,P phosphor possess good OSL properties having sensitivity comparable to that of commercially available Al2O3:C (Landauer Inc.). For the luminescence averaged over 3s the obtained OSL is 37% of that commercial available Al2O3:C. Of the several phosphors investigated, phosphor with impurities concentration Mg(0.01mol%), Cu(0.2mol%), P(1mol%) shows good OSL sensitivity good linearity in the 10mGy to 1Gy dose range and negligible fading. This sample shows a intense single TL peak around 350°C which gets depleted by 14% after the OSL readout. This imply that maximum OSL is coming from deep traps giving stability to the signal. The ease of preparation along with other good OSL properties will make this phosphor suitable for radiation dosimetry applications using OSL. PMID:26926379

  5. Imaging performance of the EUV high NA anamorphic system

    NASA Astrophysics Data System (ADS)

    van Ingen Schenau, Koen; Bottiglieri, Gerardo; van Schoot, Jan; Neumann, Jens-Timo; Roesch, Matthias

    2015-09-01

    This paper presents the predicted imaging performance for an anamorphic EUV high NA (>0.5) exposure system with a 4x magnification in X orientation and a 8x magnification in Y orientation. It has a half field size with which the productivity requirements can be maintained. The main findings of the study are that horizontal and vertical features have very similar process window sizes despite magnification difference. A new definition of the Mask Error Factor (MEF) is introduced that is more relevant for anamorphic imaging; it shows that reticle CD errors have 2x larger impact for vertical compared to horizontal features. For dark field horizontal two-bar trenches relatively small mask induced focus shift was observed compared to the 0.33NA case, probably due to the relatively small Mask Angle of Incidence in the Y orientation with the 8x magnification. Finally a Ni type absorber has potential to further improve imaging performance.

  6. Phase diagram studies on the Na-Mo-O system

    NASA Astrophysics Data System (ADS)

    Gnanasekaran, T.; Mahendran, K. H.; Kutty, K. V. G.; Mathews, C. K.

    1989-06-01

    The phase diagram of the Na-Mo-O ternary system is of interest in interpreting the behaviour of structural materials in the sodium circuits of fast breeder reactors and sodium-filled heat pipes. Experiments involving heating of sodium oxide with molybdenum metal under vacuum, selective removal of oxygen from polymolybdates by reducing them under hydrogen and confirmation of the coexistence of various phase mixtures were conducted in the temperature range of 673 to 923 K. Phase fields involving molybdenum metal, dioxide of molybdenum and ternary compounds were derived from these results. The ternary phase diagram of the Na-Mo-O system was constructed and isothermal cross sections of the phase diagram are presented.

  7. Performance comparison of MoNA and LISA neutron detectors

    NASA Astrophysics Data System (ADS)

    Purtell, Kimberly; Rethman, Kaitlynne; Haagsma, Autumn; Finck, Joseph; Smith, Jenna; Snyder, Jesse

    2010-11-01

    In 2002 eight primarily undergraduate institutions constructed and tested the Modular Neutron Array (MoNA) which has been used to detect high energy neutrons at the National Superconducting Cyclotron Laboratory (NSCL). Nine institutions have now designed, constructed and tested the Large-area multi-Institutional Scintillator Array (LISA) neutron detector which will be used at the NSCL and the future Facility for Rare Isotope Beams (FRIB). Both detectors are comprised of 144 detector modules. Each module is a 200 x 10 x 10 cm^3 bar organic plastic scintillator with a photomultiplier tube mounted on each end. Using cosmic rays and a gamma source, we compared the performance of MoNA and LISA by using the same electronics to check light attenuation, position resolution, rise times, and cosmic ray peak widths. Results will be presented.

  8. Membrane Na+-pyrophosphatases can transport protons at low sodium concentrations.

    PubMed

    Luoto, Heidi H; Nordbo, Erika; Baykov, Alexander A; Lahti, Reijo; Malinen, Anssi M

    2013-12-01

    Membrane-bound Na(+)-pyrophosphatase (Na(+)-PPase), working in parallel with the corresponding ATP-energized pumps, catalyzes active Na(+) transport in bacteria and archaea. Each ~75-kDa subunit of homodimeric Na(+)-PPase forms an unusual funnel-like structure with a catalytic site in the cytoplasmic part and a hydrophilic gated channel in the membrane. Here, we show that at subphysiological Na(+) concentrations (<5 mM), the Na(+)-PPases of Chlorobium limicola, four other bacteria, and one archaeon additionally exhibit an H(+)-pumping activity in inverted membrane vesicles prepared from recombinant Escherichia coli strains. H(+) accumulation in vesicles was measured with fluorescent pH indicators. At pH 6.2-8.2, H(+) transport activity was high at 0.1 mM Na(+) but decreased progressively with increasing Na(+) concentrations until virtually disappearing at 5 mM Na(+). In contrast, (22)Na(+) transport activity changed little over a Na(+) concentration range of 0.05-10 mM. Conservative substitutions of gate Glu(242) and nearby Ser(243) and Asn(677) residues reduced the catalytic and transport functions of the enzyme but did not affect the Na(+) dependence of H(+) transport, whereas a Lys(681) substitution abolished H(+) (but not Na(+)) transport. All four substitutions markedly decreased PPase affinity for the activating Na(+) ion. These results are interpreted in terms of a model that assumes the presence of two Na(+)-binding sites in the channel: one associated with the gate and controlling all enzyme activities and the other located at a distance and controlling only H(+) transport activity. The inherent H(+) transport activity of Na(+)-PPase provides a rationale for its easy evolution toward specific H(+) transport.

  9. Caustic Recycle from Hanford Tank Waste Using Large Area NaSICON Structures (LANS)

    SciTech Connect

    Fountain, Matthew S.; Sevigny, Gary J.; Balagopal, S.; Bhavaraju, S.

    2009-03-31

    This report presents the results of a 5-day test of an electrochemical bench-scale apparatus using a proprietary (NAS-GY) material formulation of a (Na) Super Ion Conductor (NaSICON) membrane in a Large Area NaSICON Structures (LANS) configuration. The primary objectives of this work were to assess system performance, membrane seal integrity, and material degradation while removing Na from Group 5 and 6 tank waste from the Hanford Site.

  10. Excitatory sympathetic reflex in NaCl-sensitive spontaneously hypertensive rats.

    PubMed

    Nakamura, Y; Calhoun, D A; Chen, Y F; Wyss, J M; Oparil, S

    1993-09-01

    We have previously demonstrated blunted reflex responses of lumbar sympathetic nerve activity during volume expansion in NaCl-sensitive spontaneously hypertensive rats maintained on basal (1% NaCl) diets compared with NaCl-resistant spontaneously hypertensive rats, Wistar-Kyoto rats, and Sprague-Dawley rats. The current study tested the hypothesis that chronic ingestion of a high (8%) NaCl diet further blunts cardiopulmonary reflex function in the NaCl-sensitive spontaneously hypertensive rat. After 3 weeks of a 1% or 8% NaCl diet, male rats of all four strains were instrumented with femoral arterial and venous cannulas and lumbar nerve recording electrodes at 10 weeks of age. Two days later, conscious rats were infused with whole blood to expand blood volume. NaCl-sensitive spontaneously hypertensive rats maintained on a 1% NaCl diet had blunted responses of nerve activity to acute volume expansion compared with control strains. NaCl-sensitive spontaneously hypertensive rats maintained on an 8% NaCl diet had increases in nerve activity responses to volume expansion. In a second experiment, the volume expansion protocol was repeated in anesthetized NaCl-sensitive spontaneously hypertensive rats that had been subjected to sinoaortic denervation after 3 weeks of a 1% or 8% NaCl diet. After sinoaortic denervation, an increase in nerve activity was again observed during volume expansion in animals fed the 8% NaCl diet. In animals fed the 1% NaCl diet, changes in nerve activity were variable. The excitatory response was significantly reduced after bilateral vagotomy. These studies suggest that blood pressure regulation in NaCl-sensitive spontaneously hypertensive rats is a complex interaction of excitatory and inhibitory sympathetic reflex systems that is altered by high dietary NaCl exposure.

  11. The Offline Software Framework of the NA61/SHINE Experiment

    NASA Astrophysics Data System (ADS)

    Sipos, Roland; Laszlo, Andras; Marcinek, Antoni; Paul, Tom; Szuba, Marek; Unger, Michael; Veberic, Darko; Wyszynski, Oskar

    2012-12-01

    NA61/SHINE (SHINE = SPS Heavy Ion and Neutrino Experiment) is an experiment at the CERN SPS using the upgraded NA49 hadron spectrometer. Among its physics goals are precise hadron production measurements for improving calculations of the neutrino beam flux in the T2K neutrino oscillation experiment as well as for more reliable simulations of cosmic-ray air showers. Moreover, p+p, p+Pb and nucleus+nucleus collisions will be studied extensively to allow for a study of properties of the onset of deconfinement and search for the critical point of strongly interacting matter. Currently NA61/SHINE uses the old NA49 software framework for reconstruction, simulation and data analysis. The core of this legacy framework was developed in the early 1990s. It is written in different programming and scripting languages (C, pgi-Fortran, shell) and provides several concurrent data formats for the event data model, which includes also obsolete parts. In this contribution we will introduce the new software framework, called Shine, that is written in C++ and designed to comprise three principal parts: a collection of processing modules which can be assembled and sequenced by the user via XML files, an event data model which contains all simulation and reconstruction information based on STL and ROOT streaming, and a detector description which provides data on the configuration and state of the experiment. To assure a quick migration to the Shine framework, wrappers were introduced that allow to run legacy code parts as modules in the new framework and we will present first results on the cross validation of the two frameworks.

  12. Redetermination of durangite, NaAl(AsO4)F

    PubMed Central

    Downs, Gordon W.; Yang, Betty N.; Thompson, Richard M.; Wenz, Michelle D.; Andrade, Marcelo B.

    2012-01-01

    The crystal structure of durangite, ideally NaAl(AsO4)F (chemical name sodium aluminium arsenate fluoride), has been determined previously [Kokkoros (1938). Z. Kristallogr. 99, 38–49] using Weissenberg film data without reporting displacement parameters of atoms or a reliability factor. This study reports the redetermination of the structure of durangite using single-crystal X-ray diffraction data from a natural sample with composition (Na0.95Li0.05)(Al0.91Fe3+ 0.07Mn3+ 0.02)(AsO4)(F0.73(OH)0.27) from the type locality, the Barranca mine, Coneto de Comonfort, Durango, Mexico. Durangite is isostructural with minerals of the titanite group in the space group C2/c. Its structure is characterized by kinked chains of corner-sharing AlO4F2 octa­hedra parallel to the c axis. These chains are cross-linked by isolated AsO4 tetra­hedra, forming a three-dimensional framework. The Na+ cation (site symmetry 2) occupies the inter­stitial sites and is coordinated by one F− and six O2− anions. The AlO4F2 octa­hedron has symmetry -1; it is flattened, with the Al—F bond length [1.8457 (4) Å] shorter than the Al—O bond lengths [1.8913 (8) and 1.9002 (9) Å]. Examination of the Raman spectra for arsenate minerals in the titanite group reveals that the position of the band originating from the As—O symmetric stretching vibrations shifts to lower wavenumbers from durangite, maxwellite [ideally NaFe(AsO4)F], to tilasite [CaMg(AsO4)F]. PMID:23284315

  13. Cosmogenic radionuclide production in NaI(Tl) crystals

    NASA Astrophysics Data System (ADS)

    Amaré, J.; Cebrián, S.; Cuesta, C.; García, E.; Ginestra, C.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2015-02-01

    The production of long-lived radioactive isotopes in materials due to the exposure to cosmic rays on Earth surface can be an hazard for experiments demanding ultra-low background conditions, typically performed deep underground. Production rates of cosmogenic isotopes in all the materials present in the experimental set-up, as well as the corresponding cosmic rays exposure history, must be both well known in order to assess the relevance of this effect in the achievable sensitivity of a given experiment. Although NaI(Tl) scintillators are being used in experiments aiming at the direct detection of dark matter since the first nineties of the last century, very few data about cosmogenic isotopes production rates have been published up to date. In this work we present data from two 12.5 kg NaI(Tl) detectors, developed in the frame of the ANAIS project, which were installed inside a convenient shielding at the Canfranc Underground Laboratory just after finishing surface exposure to cosmic rays. The very fast start of data taking allowed to identify and quantify isotopes with half-lives of the order of tens of days. Initial activities underground have been measured and then production rates at sea level have been estimated following the history of detectors; values of about a few tens of nuclei per kg and day for Te isotopes and 22Na and of a few hundreds for I isotopes have been found. These are the first direct estimates of production rates of cosmogenic nuclides in NaI crystals. A comparison of the so deduced rates with calculations using typical cosmic neutron flux at sea level and a carefully selected description of excitation functions will be also presented together with an estimate of the corresponding contribution to the background at low and high energies, which can be relevant for experiments aiming at rare events searches.

  14. Comparison Of NaI And HPGe Minimum Detectable Activities

    SciTech Connect

    Bailey, Paul

    2002-11-30

    The Minimum Detectable Activity of a 76 mm by 76 mm (3" by 3") sodium iodide (NaI) crystal and 18 %, 42 % and 68 % efficient HPGe detectors were calculated and compared for gamma-ray spectrometry with count times in the range of 1 second to 15 minutes. All cases were for in situ measurements with a surface distribution source and a detector height of 1 meter. The radionuclides considered were 137Cs and 60Co.

  15. Raltegravir in treatment naïve patients

    PubMed Central

    2009-01-01

    Raltegravir is the first integrase inhibitor approved for the treatment of HIV infection based on the superior efficacy it showed compared to optimized backbone therapy alone in patients harboring multidrug resistant viruses. Studies on naïve patients showed comparable efficacy of raltegravir and efavirenz and just recently the US Food and Drug Administration (FDA) approved raltegravir for the use in naïve patients based on the favorable results of the international double-blind phase III STARTMRK trial. Additional interesting findings were the faster, and not yet explained, decay of HIV-1 RNA and the higher CD4+ cells increase in the raltegravir group as compared to the efavirenz group. Raltegravir is generally well tolerated and adverse events were generally similar in raltegravir and comparator arms throughout all studies. When compared to efavirenz, patients on raltegravir showed less incidence of central nervous system-related adverse events. In studies on experienced patients higher incidence of cancers was found in the raltegravir arm: a relationship with the drug was, however not confirmed in a recent review considering all raltegravir studies. Raltegravir also showed a safe lipid profile expecially in naïve patients, finding that renders the drug attractive for patients with other cardiovascular risk factors. All this characteristics in association with its specific mechanism of action, make raltegravir an interesting drug for naïve patients and a large use in this type of patients is predictable. Only time and experience, however, will tell us whether raltegravir will maintain its promises in the long run. PMID:19959413

  16. Lanthanum-NaY zeolite ion exchange. 2; Kinetics

    SciTech Connect

    Lee, T.Y.; Lu, T.S.; Chen, S.H.; Chao, K.J. )

    1990-10-01

    This paper reports on La-NaY ion exchange breakthrough curves which were obtained experimentally at 27 and 60{degrees}C. A mathematical model of an ion exchanger was formulated and employed to calculate the ion exchanger coefficients. An ionic diffusion coefficient of the order of 10{sup {minus}8} cm{sup 2}/s was obtained. The effects of zeolite particle size, temperature, and column packing conditions on the kinetics of the exchange were investigated also.

  17. Serine protease activation of near-silent epithelial Na+ channels.

    PubMed

    Caldwell, Ray A; Boucher, Richard C; Stutts, M Jackson

    2004-01-01

    The regulation of epithelial Na+ channel (ENaC) function is critical for normal salt and water balance. This regulation is achieved through cell surface insertion/retrieval of channels, by changes in channel open probability (Po), or through a combination of these processes. Epithelium-derived serine proteases, including channel activating protease (CAP) and prostasin, regulate epithelial Na+ transport, but the molecular mechanism is unknown. We tested the hypothesis that extracellular serine proteases activate a near-silent ENaC population resident in the plasma membrane. Single-channel events were recorded in outside-out patches from fibroblasts (NIH/3T3) stably expressing rat alpha-, beta-, and gamma-subunits (rENaC), before and during exposure to trypsin, a serine protease homologous to CAP and prostasin. Under baseline conditions, near-silent patches were defined as having rENaC activity (NPo) < 0.03, where N is the number of channels. Within 1-5 min of 3 microg/ml bath trypsin superfusion, NPo increased approximately 66-fold (n = 7). In patches observed to contain a single functional channel, trypsin increased Po from 0.02 +/- 0.01 to 0.57 +/- 0.03 (n = 3, mean +/- SE), resulting from the combination of an increased channel open time and decreased channel closed time. Catalytic activity was required for activation of near-silent ENaC. Channel conductance and the Na+/Li+ current ratio with trypsin were similar to control values. Modulation of ENaC Po by endogenous epithelial serine proteases is a potentially important regulator of epithelial Na+ transport, distinct from the regulation achieved by hormone-induced plasma membrane insertion of channels. PMID:12967915

  18. Time-dependent MOS breakdown. [of Na contaminated capacitors

    NASA Technical Reports Server (NTRS)

    Li, S. P.; Bates, E. T.; Maserjian, J.

    1976-01-01

    A general model for time-dependent breakdown in metal-oxide-silicon (MOS) structures is developed and related to experimental measurements on samples deliberately contaminated with Na. A statistical method is used for measuring the breakdown probability as a function of log time and applied field. It is shown that three time regions of breakdown can be explained respectively in terms of silicon surface defects, ion emission from the metal interface, and lateral ion diffusion at the silicon interface.

  19. Sodium Ion Transport Mechanisms in Antiperovskite Electrolytes Na3OBr and Na4OI2: An in Situ Neutron Diffraction Study.

    PubMed

    Zhu, Jinlong; Wang, Yonggang; Li, Shuai; Howard, John W; Neuefeind, Jörg; Ren, Yang; Wang, Hui; Liang, Chengdu; Yang, Wenge; Zou, Ruqiang; Jin, Changqing; Zhao, Yusheng

    2016-06-20

    Na-rich antiperovskites are recently developed solid electrolytes with enhanced sodium ionic conductivity and show promising functionality as a novel solid electrolyte in an all solid-state battery. In this work, the sodium ionic transport pathways of the parent compound Na3OBr, as well as the modified layered antiperovskite Na4OI2, were studied and compared through temperature-dependent neutron diffraction combined with the maximum entropy method. In the cubic Na3OBr antiperovskite, the nuclear density distribution maps at 500 K indicate that sodium ions hop within and among oxygen octahedra, and Br(-) ions are not involved. In the tetragonal Na4OI2 antiperovskite, Na ions, which connect octahedra in the ab plane, have the lowest activation energy barrier. The transport of sodium ions along the c axis is assisted by I(-) ions. PMID:27251879

  20. Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

    NASA Astrophysics Data System (ADS)

    Sasaki, Koichi; Ishigame, Hiroaki; Nishiyama, Shusuke

    2015-07-01

    This paper reports the density distributions of OH, Na, water vapor and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution. The densities of OH, Na and H2O had different spatial distributions, while the Na density had a similar distribution to mist, suggesting that mist is the source of Na in the gas phase. When the flow rate of helium toward the electrolyte surface was increased, the distributions of all the species densities concentrated in the neighboring region to the electrolyte surface more significantly. The densities of all the species were sensitive to the electric polarity of the power supply. In particular, we never detected Na and mist when the electrolyte worked as the anode of the dc discharge. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  1. Direct observation of electronic conductivity transitions and solid electrolyte interphase stability of Na2Ti3O7 electrodes for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, Maider; Nobili, Francesco; Muñoz-Márquez, Miguel Ángel; Rojo, Teófilo; Casas-Cabanas, Montse

    2016-10-01

    This communication reports the first experimental evidence of an interesting change of transport properties, and particularly of electron conductivity, during the Na+ insertion/extraction process in Na2Ti3O7 negative electrodes. Probed by electrochemical impedance spectroscopy, for 0.0 ≤ x < 1.4 in Na2+xTi3O7 the material exhibits insulator behaviour, the bulk electronic conductivity being the limiting factor in the insertion process. After further Na+ insertion, the material becomes electronic conductor and at around 0.13 V vs. Na+/Na the rate of interfacial charge-transfer becomes the limiting factor. The observed conductivity transition is reversible upon cycling. Additionally, this impedance study sheds new light on the solid electrolyte interphase layer performance which is found to be unstable upon electrochemical cycling and negatively contributes on the capacity fading observed for this electrode material.

  2. Characterization of the size and orientation of Na and Cl2 nanocrystals in electron irradiated NaCl crystals by means of synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Sulyanov, S. N.; Kheiker, D. M.; Dorovatovskii, P. V.; Sugonyako, A. V.; Vainshtein, D. I.; den Hartog, H. W.

    2007-06-01

    Samples of synthetic NaCl crystals have been exposed to doses of electron irradiation up to 10-2 TGy (1 Trad) at about 100 °C, and studied subsequently at T = 95 K by means of synchrotron radiation (SR). In addition to the earlier established Kurdjumov-Sachs orientation relationship (K-S OR) for Na precipitates, the following OR is revealed between solid chlorine and the host NaCl crystal system: {\\{}001{\\}}_{\\mathrm {Cl}} \\parallel {\\{}001{\\}}_{\\mathrm {NaCl}} , \\langle 110\\rangle_{\\mathrm {Cl}}\\parallel \\langle 110\\rangle_{\\mathrm {NaCl}} . The size and shape of the Cl2 precipitates has been studied as a function of the amount of radiation damage (i.e. the concentrations of Na and Cl2).

  3. Effect of cation substitution on structural transition: synthesis, characterization and theoretical studies of NaCa4B3O9, NaCaBO3, NaSrBO3 and Li4CaB2O6.

    PubMed

    Yang, Yun; Su, Xin; Pan, Shilie; Yang, Zhihua

    2015-10-21

    Single crystals of NaCa4B3O9, NaCaBO3, NaSrBO3 and Li4CaB2O6 have been successfully synthesized through conventional high-temperature solid-state reactions. They are structurally characterized by single crystal X-ray diffraction and exhibit three-dimensional crystal structures consisting of isolated planar BO3 as fundamental building blocks. Interestingly, for the centrosymmetric crystal structure of NaCaBO3 (Na3Ca3B3O9), as 2/3 of the Na(+) ions are substituted by Ca(2+) ions, NaCa4B3O9 is obtained and crystallizes in the noncentrosymmetric space group Ama2 (crystal class mm2). A second harmonic generation (SHG) test of the title compound by the Kurtz-Perry method shows that NaCa4B3O9 can be phase matchable with an effective SHG coefficient approximately one-half that of KH2PO4 (KDP). Studies of their optical properties as well as band structure calculations based on density functional theory methods have been also performed. NaCa4B3O9 possesses a moderate birefringence of about 0.05 at 1064 nm. To explain the difference in optical nonlinearity we compared the electronic structures of NaCa4B3O9, KCa4B3O9 and KSr4B3O9 crystals, in particular at the bottom of the conduction band (CB) and the top of the valence band (VB), since they are known to play a primary role in SHG. These electronic structures are responsible for the optical-nonlinearity of NaCa4B3O9, KCa4B3O9 and KSr4B3O9 crystals. PMID:26387438

  4. Hydrogenation properties of KSi and NaSi Zintl phases.

    PubMed

    Tang, Wan Si; Chotard, Jean-Noël; Raybaud, Pascal; Janot, Raphaël

    2012-10-14

    The recently reported KSi-KSiH(3) system can store 4.3 wt% of hydrogen reversibly with slow kinetics of several hours for complete absorption at 373 K and complete desorption at 473 K. From the kinetics measured at different temperatures, the Arrhenius plots give activation energies (E(a)) of 56.0 ± 5.7 kJ mol(-1) and 121 ± 17 kJ mol(-1) for the absorption and desorption processes, respectively. Ball-milling with 10 wt% of carbon strongly improves the kinetics of the system, i.e. specifically the initial rate of absorption becomes about one order of magnitude faster than that of pristine KSi. However, this fast absorption causes a disproportionation into KH and K(8)Si(46), instead of forming the KSiH(3) hydride from a slow absorption. This disproportionation, due to the formation of stable KH, leads to a total loss of reversibility. In a similar situation, when the pristine Zintl NaSi phase absorbs hydrogen, it likewise disproportionates into NaH and Na(8)Si(46), indicating a very poorly reversible reaction.

  5. A controllable molecular sieve for Na+ and K+ ions.

    PubMed

    Gong, Xiaojing; Li, Jichen; Xu, Ke; Wang, Jianfeng; Yang, Hui

    2010-02-17

    The selective rate of specific ion transport across nanoporous material is critical to biological and nanofluidic systems. Molecular sieves for ions can be achieved by steric and electrical effects. However, the radii of Na(+) and K(+) are quite similar; they both carry a positive charge, making them difficult to separate. Biological ionic channels contain precisely arranged arrays of amino acids that can efficiently recognize and guide the passage of K(+) or Na(+) across the cell membrane. However, the design of inorganic channels with novel recognition mechanisms that control the ionic selectivity remains a challenge. We present here a design for a controllable ion-selective nanopore (molecular sieve) based on a single-walled carbon nanotube with specially arranged carbonyl oxygen atoms modified inside the nanopore, which was inspired by the structure of potassium channels in membrane spanning proteins (e.g., KcsA). Our molecular dynamics simulations show that the remarkable selectivity is attributed to the hydration structure of Na(+) or K(+) confined in the nanochannels, which can be precisely tuned by different patterns of the carbonyl oxygen atoms. The results also suggest that a confined environment plays a dominant role in the selectivity process. These studies provide a better understanding of the mechanism of ionic selectivity in the KcsA channel and possible technical applications in nanotechnology and biotechnology, including serving as a laboratory-in-nanotube for special chemical interactions and as a high-efficiency nanodevice for purification or desalination of sea and brackish water. PMID:20102186

  6. Automatic residue removal for high-NA extreme illumination

    NASA Astrophysics Data System (ADS)

    Moon, James; Nam, Byong-Sub; Jeong, Joo-Hong; Kong, Dong-Ho; Nam, Byung-Ho; Yim, Dong Gyu

    2007-10-01

    An epidemic for smaller node has been that, as the device architecture shrinks, lithography process requires high Numerical Aperture (NA), and extreme illumination system. This, in turn, creates many lithography problems such as low lithography process margin (Depth of Focus, Exposure Latitude), unstable Critical Dimension (CD) uniformity and restricted guideline for device design rule and so on. Especially for high NA, extreme illumination such as immersion illumination systems, above all the related problems, restricted design rule due to forbidden pitch is critical and crucial issue. This forbidden pitch is composed of numerous optical effects but majority of these forbidden pitch compose of photo resist residue and these residue must be removed to relieve some room for already tight design rule. In this study, we propose automated algorithm to remove photo resist residue due to high NA and extreme illumination condition. This algorithm automatically self assembles assist patterns based on the original design layout, therefore insuring the safety and simplicity of the generated assist pattern to the original design and removes any resist residue created by extreme illumination condition. Also we tested our automated algorithm on full chip FLASH memory device and showed the residue removal effect by using commercial verification tools as well as on actual test wafer.

  7. Actinic EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno. B.; Kemp, Charles D.; Huh, S.; Han, H.-S.; Naulleau, P.; Huh, S.

    2008-03-24

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is an EUV-wavelength mask inspection microscope designed for direct aerial image measurements, and pre-commercial EUV mask research. Operating on a synchrotron bending magnet beamline, the AIT uses an off-axis Fresnel zoneplate lens to project a high-magnification EUV image directly onto a CCD camera. We present the results of recent system upgrades that have improved the imaging resolution, illumination uniformity, and partial coherence. Benchmarking tests show image contrast above 75% for 100-nm mask features, and significant improvements and across the full range of measured sizes. The zoneplate lens has been replaced by an array of user-selectable zoneplates with higher magnification and NA values up to 0.0875, emulating the spatial resolution of a 0.35-NA 4x EUV stepper. Illumination uniformity is above 90% for mask areas 2-{micro}m-wide and smaller. An angle-scanning mirror reduces the high coherence of the synchrotron beamline light source giving measured {sigma} values of approximately 0.125 at 0.0875 NA.

  8. Benchmarking EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno B.; Kemp, Charles D.; Huh, S.; Han, H.-S.; Naulleau, P.; Gunion, R.F.

    2008-09-18

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is an EUV-wavelength mask inspection microscope designed for direct aerial image measurements, and pre-commercial EUV mask research. Operating on a synchrotron bending magnet beamline, the AIT uses an off-axis Fresnel zoneplate lens to project a high-magnification EUV image directly onto a CCD camera. We present the results of recent system upgrades that have improved the imaging resolution, illumination uniformity, and partial coherence. Benchmarking tests show image contrast above 75% for 100-nm mask features, and significant improvements and across the full range of measured sizes. The zoneplate lens has been replaced by an array of user-selectable zoneplates with higher magnification and NA values up to 0.0875, emulating the spatial resolution of a 0.35-NA 4 x EUV stepper. Illumination uniformity is above 90% for mask areas 2-{micro}m-wide and smaller. An angle-scanning mirror reduces the high coherence of the synchrotron beamline light source giving measured {sigma} values of approximately 0.125 at 0.0875 NA.

  9. A controllable molecular sieve for Na+ and K+ ions.

    PubMed

    Gong, Xiaojing; Li, Jichen; Xu, Ke; Wang, Jianfeng; Yang, Hui

    2010-02-17

    The selective rate of specific ion transport across nanoporous material is critical to biological and nanofluidic systems. Molecular sieves for ions can be achieved by steric and electrical effects. However, the radii of Na(+) and K(+) are quite similar; they both carry a positive charge, making them difficult to separate. Biological ionic channels contain precisely arranged arrays of amino acids that can efficiently recognize and guide the passage of K(+) or Na(+) across the cell membrane. However, the design of inorganic channels with novel recognition mechanisms that control the ionic selectivity remains a challenge. We present here a design for a controllable ion-selective nanopore (molecular sieve) based on a single-walled carbon nanotube with specially arranged carbonyl oxygen atoms modified inside the nanopore, which was inspired by the structure of potassium channels in membrane spanning proteins (e.g., KcsA). Our molecular dynamics simulations show that the remarkable selectivity is attributed to the hydration structure of Na(+) or K(+) confined in the nanochannels, which can be precisely tuned by different patterns of the carbonyl oxygen atoms. The results also suggest that a confined environment plays a dominant role in the selectivity process. These studies provide a better understanding of the mechanism of ionic selectivity in the KcsA channel and possible technical applications in nanotechnology and biotechnology, including serving as a laboratory-in-nanotube for special chemical interactions and as a high-efficiency nanodevice for purification or desalination of sea and brackish water.

  10. Na+ and Li+ NASICON Superionic Conductors Thick Films

    NASA Astrophysics Data System (ADS)

    Perthuis, H.; Velasco, G.; Colomban, Ph.

    1984-05-01

    For microionic applications, superionic conductors have been elaborated in the form of thick films, using silk-screen printable powders. Na3Zr2Si2PO12, Na3.1Zr1.55Si2.3P0.7O11 and Li0.8Zr1.8Ta0.2(PO4)3 compositions are synthesized by a sol-gel process involving hydrolysis-polycondensation reactions of metal-organic alcoholic solutions. A thermal treatment (600°C-800°C) allows to obtain very fine particles (<1 μm) with the pure NASICON phase. Inks are prepared with these powders, an organic binder, volatile fluidifying agents and mineralizers. The layers, about 50 μm in thickness, are achieved by successive deposits and sinterings (950°C-1050°C) onto alumina substrates. Films conductivity is determined by the complex impedance method. Values measured at 300°C (Na+: σ˜10-2 Ω-1cm-1, EA{=}0.25 eV, Li+: σ˜5 10-4 Ω-1cm-1, EA{=}0.5 eV) reach those obtained with well-densified ceramics. An anisotropic behaviour related to microstructure is pointed out.

  11. Influence of spin multiplicity on the melting of Na55(+).

    PubMed

    Vásquez-Pérez, J M; Gamboa, G U; Mejía-Rodríguez, D; Alvarez-Ibarra, A; Geudtner, G; Calaminici, P; Köster, A M

    2015-11-19

    The influence of spin multiplicity on the melting of the Na55(+) cluster has been investigated by means of all-electron Kohn-Sham Born-Oppenheimer molecular dynamics simulations. On the basis of the quantitative agreement between the experimental and theoretical melting temperature and latent heat a detailed analysis of the cluster dynamics was performed. This analysis showed a significant structure deformation of the cluster that is inconsistent with the geometrical shell closing concept. In subsequent structure optimizations a high-spin ground state in perfect icosahedral symmetry was found for the Na55(+) cluster. The Born-Oppenheimer molecular dynamics of this high-spin Na55(+) cluster indicates a particular thermal stability of the icosahedral cluster structure. A new electronic mechanism, named subshell closing, is suggested as the origin for this enhanced thermal stability of the icosahedral cluster structure. This mechanism is a natural extension of the common jellium model. By its nature, the subshell closing mechanism is general for finite systems and expected to be found in many other clusters for which the jellium model is applicable. PMID:26551347

  12. 78 FR 47053 - Proposed Collection; Comment Request for Form 706-NA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ... Internal Revenue Service Proposed Collection; Comment Request for Form 706-NA AGENCY: Internal Revenue...(c)(2)(A)). Currently, the IRS is soliciting comments concerning Form 706-NA, United States Estate... nonresident not a citizen of the United States. OMB Number: 1545-0531. Form Number: 706-NA. Abstract: Form...

  13. 24 CFR 401.473 - HUD grants for rehabilitation under section 236(s) of NA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false HUD grants for rehabilitation under section 236(s) of NA. 401.473 Section 401.473 Housing and Urban Development Regulations Relating to... 236(s) of NA. HUD will consider a direct grant for rehabilitation under section 236(s) of the NA...

  14. The thermodynamic characteristics of vaporization in the NaI-PrI3 system

    NASA Astrophysics Data System (ADS)

    Motalov, V. B.; Kudin, L. S.; Markus, T.

    2009-05-01

    The vaporization of the NaI-PrI3 quasi-binary system was studied by high-temperature mass spectrometry over the whole concentration range. At 623-994 K, saturated vapor contained not only (NaI) n and (PrI3) n molecules ( n = 1, 2) and Na+(NaI) n ( n = 0-4) and I-(PrI3) n ( n = 1-2) ions but also mixed molecular and ionic associates recorded for the first time (NaPrI4, Na2PrI5, NaPrI{3/+}, Na2PrI{4/+}, Na3PrI{5/+}, Na4PrI{6/+}, NaPrI{5/-}, and NaPr2I{8/-}). The partial vapor pressures of molecules were calculated, and the equilibrium constants of the dissociation of neutral and charged associates were measured. The enthalpies of molecular and ion-molecular reactions were determined, and the enthalpies of formation of gaseous molecules and ions were obtained.

  15. Kinetic Behavior of Salmonella on Low NaNO2 Sausages during Aerobic and Vacuum Storage

    PubMed Central

    Ha, Jimyeong; Gwak, Eunji; Oh, Mi-Hwa; Park, Beomyoung; Lee, Jeeyeon; Kim, Sejeong; Lee, Heeyoung; Lee, Soomin; Yoon, Yohan; Choi, Kyoung-Hee

    2016-01-01

    This study evaluated the growth kinetics of Salmonella spp. in processed meat products formulated with low sodium nitrite (NaNO2). A 5-strain mixture of Salmonella spp. was inoculated on 25-g samples of sausages formulated with sodium chloride (NaCl) (1.0%, 1.25%, and 1.5%) and NaNO2 (0 and 10 ppm) followed by aerobic or vacuum storage at 10℃ and 15℃ for up to 816 h or 408 h, respectively. The bacterial cell counts were enumerated on xylose lysine deoxycholate agar, and the modified Gompertz model was fitted to the Salmonella cell counts to calculate the kinetic parameters as a function of NaCl concentration on the growth rate (GR; Log CFU/g/h) and lag phase duration (LPD; h). A linear equation was then fitted to the parameters to evaluate the effect of NaCl concentration on the kinetic parameters. The GR values of Salmonella on sausages were higher (p<0.05) with 10 ppm NaNO2 concentration than with 0 ppm NaNO2. The GR values of Salmonella decreased (p<0.05) as NaCl concentration increased, especially at 10℃. This result indicates that 10 ppm NaNO2 may increase Salmonella growth at low NaCl concentrations, and that NaCl plays an important role in inhibiting Salmonella growth in sausages with low NaNO2. PMID:27194936

  16. Effects of eugenol on Na+ currents in rat dorsal root ganglion neurons.

    PubMed

    Cho, Jeong Seon; Kim, Tae Hoon; Lim, Jae-Min; Song, Jin-Ho

    2008-12-01

    Eugenol is an aromatic molecule found in several plants and widely used in dentistry for analgesic and antiseptic purposes. It inhibits pro-inflammatory mediators including nitric oxide synthase, cyclooxygenase and lipoxygenase. It also regulates ion channels involved in pain signaling, such as TRPV1 receptor, high-voltage-activated Ca(2+) channels, NMDA receptor and GABA(A) receptor. The expression and functional properties of voltage-gated Na(+) channels in primary sensory neurons are altered following inflammation or nerve injury. To elucidate an involvement of Na(+) channels in the eugenol-induced analgesia we investigated the effects of eugenol on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na(+) currents in acutely dissociated rat dorsal root ganglion neurons. Eugenol inhibited TTX-S and TTX-R Na(+) currents in a concentration-dependent manner. The K(d) values were 308 muM and 543 muM, respectively. Eugenol did not influence the activation voltage of either type of Na(+) current. However, eugenol moved the steady-state inactivation curves of both Na(+) currents to a hyperpolarizing direction and reduced the maximal Na(+) current. Thus eugenol appears to inhibit Na(+) currents through its interaction with both resting and inactivated Na(+) channels. The recovery from inactivation of both Na(+) currents was slowed by eugenol. The eugenol inhibition of Na(+) currents was not dependent on the stimulus frequency. The inhibition of Na(+) currents is considered as one of the mechanisms by which eugenol exerts analgesia.

  17. ROS-mediated vascular homeostatic control of root-to-shoot soil Na delivery in Arabidopsis

    PubMed Central

    Jiang, Caifu; Belfield, Eric J; Mithani, Aziz; Visscher, Anne; Ragoussis, Jiannis; Mott, Richard; Smith, J Andrew C; Harberd, Nicholas P

    2012-01-01

    Sodium (Na) is ubiquitous in soils, and is transported to plant shoots via transpiration through xylem elements in the vascular tissue. However, excess Na is damaging. Accordingly, control of xylem-sap Na concentration is important for maintenance of shoot Na homeostasis, especially under Na stress conditions. Here we report that shoot Na homeostasis of Arabidopsis thaliana plants grown in saline soils is conferred by reactive oxygen species (ROS) regulation of xylem-sap Na concentrations. We show that lack of A. thaliana respiratory burst oxidase protein F (AtrbohF; an NADPH oxidase catalysing ROS production) causes hypersensitivity of shoots to soil salinity. Lack of AtrbohF-dependent salinity-induced vascular ROS accumulation leads to increased Na concentrations in root vasculature cells and in xylem sap, thus causing delivery of damaging amounts of Na to the shoot. We also show that the excess shoot Na delivery caused by lack of AtrbohF is dependent upon transpiration. We conclude that AtrbohF increases ROS levels in wild-type root vasculature in response to raised soil salinity, thereby limiting Na concentrations in xylem sap, and in turn protecting shoot cells from transpiration-dependent delivery of excess Na. PMID:23064146

  18. Sodium channel diversity in the vestibular ganglion: NaV1.5, NaV1.8, and tetrodotoxin-sensitive currents.

    PubMed

    Liu, Xiao-Ping; Wooltorton, Julian R A; Gaboyard-Niay, Sophie; Yang, Fu-Chia; Lysakowski, Anna; Eatock, Ruth Anne

    2016-05-01

    Firing patterns differ between subpopulations of vestibular primary afferent neurons. The role of sodium (NaV) channels in this diversity has not been investigated because NaV currents in rodent vestibular ganglion neurons (VGNs) were reported to be homogeneous, with the voltage dependence and tetrodotoxin (TTX) sensitivity of most neuronal NaV channels. RT-PCR experiments, however, indicated expression of diverse NaV channel subunits in the vestibular ganglion, motivating a closer look. Whole cell recordings from acutely dissociated postnatal VGNs confirmed that nearly all neurons expressed NaV currents that are TTX-sensitive and have activation midpoints between -30 and -40 mV. In addition, however, many VGNs expressed one of two other NaV currents. Some VGNs had a small current with properties consistent with NaV1.5 channels: low TTX sensitivity, sensitivity to divalent cation block, and a relatively negative voltage range, and some VGNs showed NaV1.5-like immunoreactivity. Other VGNs had a current with the properties of NaV1.8 channels: high TTX resistance, slow time course, and a relatively depolarized voltage range. In two NaV1.8 reporter lines, subsets of VGNs were labeled. VGNs with NaV1.8-like TTX-resistant current also differed from other VGNs in the voltage dependence of their TTX-sensitive currents and in the voltage threshold for spiking and action potential shape. Regulated expression of NaV channels in primary afferent neurons is likely to selectively affect firing properties that contribute to the encoding of vestibular stimuli. PMID:26936982

  19. Evaluation of Salmonella Growth at Low Concentrations of NaNO2 and NaCl in Processed Meat Products Using Probabilistic Model

    PubMed Central

    Gwak, E.; Lee, H.; Lee, S.; Oh, M-H.; Park, B-Y.; Ha, J.; Lee, J.; Kim, S.; Yoon, Y.

    2016-01-01

    This study developed probabilistic models to predict Salmonella growth in processed meat products formulated with varying concentrations of NaCl and NaNO2. A five-strain mixture of Salmonella was inoculated in nutrient broth supplemented with NaCl (0%, 0.25%, 0.5%, 0.75%, 0.5%, 1.0%, 1.25%, and 1.75%) and NaNO2 (0, 15, 30, 45, 60, 75, 90, 105, and 120 ppm). The inoculated samples were then incubated under aerobic and anaerobic conditions at 4°C, 7°C, 10°C, 12°C, and 15°C for up to 60 days. Growth (assigned the value of 1) or no growth (assigned the value of 0) for each combination was evaluated by turbidity. These growth response data were analyzed with a logistic regression to evaluate the effect of NaCl and NaNO2 on Salmonella growth. The results from the developed model were compared to the observed data obtained from the frankfurters to evaluate the performance of the model. Results from the developed model showed that a single application of NaNO2 at low concentrations did not inhibit Salmonella growth, whereas NaCl significantly (p<0.05) inhibited Salmonella growth at 10°C, 12°C, and 15°C, regardless of the presence of oxygen. At 4°C and 7°C, Salmonella growth was not observed in either aerobic or anaerobic conditions. When NaNO2 was combined with NaCl, the probability of Salmonella growth decreased. The validation value confirmed that the performance of the developed model was appropriate. This study indicates that the developed probabilistic models should be useful for describing the combinational effect of NaNO2 and NaCl on inhibiting Salmonella growth in processed meat products. PMID:26954121

  20. Probabilistic Models to Predict the Growth Initiation Time for Pseudomonas spp. in Processed Meats Formulated with NaCl and NaNO2

    PubMed Central

    Park, Beomyoung; Oh, Mihwa

    2014-01-01

    This study developed probabilistic models to determine the initiation time of growth of Pseudomonas spp. in combinations with NaNO2 and NaCl concentrations during storage at different temperatures. The combination of 8 NaCl concentrations (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, and 1.75%) and 9 NaNO2 concentrations (0, 15, 30, 45, 60, 75, 90, 105, and 120 ppm) were prepared in a nutrient broth. The medium was placed in the wells of 96-well microtiter plates, followed by inoculation of a five-strain mixture of Pseudomonas in each well. All microtiter plates were incubated at 4, 7, 10, 12, and 15℃ for 528, 504, 504, 360 and 144 h, respectively. Growth (growth initiation; GI) or no growth was then determined by turbidity every 24 h. These growth response data were analyzed by a logistic regression to produce growth/no growth interface of Pseudomonas spp. and to calculate GI time. NaCl and NaNO2 were significantly effective (p<0.05) on inhibiting Pseudomonas spp. growth when stored at 4-12℃. The developed model showed that at lower NaCl concentration, higher NaNO2 level was required to inhibit Pseudomonas growth at 4-12℃. However, at 15℃, there was no significant effect of NaCl and NaNO2. The model overestimated GI times by 58.2±17.5 to 79.4±11%. These results indicate that the probabilistic models developed in this study should be useful in calculating the GI times of Pseudomonas spp. in combination with NaCl and NaNO2 concentrations, considering the over-prediction percentage. PMID:26761668

  1. Excitation of skeletal muscle is a self-limiting process, due to run-down of Na+, K+ gradients, recoverable by stimulation of the Na+, K+ pumps

    PubMed Central

    Clausen, Torben

    2015-01-01

    The general working hypothesis of this study was that muscle fatigue and force recovery depend on passive and active fluxes of Na+ and K+. This is tested by examining the time-course of excitation-induced fluxes of Na+ and K+ during 5–300 sec of 10–60 Hz continuous electrical stimulation in rat extensor digitorum longus (EDL) muscles in vitro and in vivo using 22Na and flame photometric determination of Na+ and K+. 60 sec of 60 Hz stimulation rapidly increases 22Na influx, during the initial phase (0–15 sec) by 0.53 μmol(sec)−1(g wet wt.)−1, sixfold faster than in the later phase (15–60 sec). These values agree with flame photometric measurements of Na+ content. The progressive reduction in the rate of excitation-induced Na+ uptake is likely to reflect gradual loss of excitability due to accumulation of K+ in the extracellular space and t-tubules leading to depolarization. This is in keeping with the concomitant progressive loss of contractile force previously demonstrated. During electrical stimulation rat muscles rapidly reach high rates of active Na+, K+-transport (in EDL muscles a sevenfold increase and in soleus muscles a 22-fold increase), allowing efficient and selective compensation for the large excitation-induced passive Na+, K+-fluxes demonstrated over the latest decades. The excitation-induced changes in passive fluxes of Na+ and K+ are both clearly larger than previously observed. The excitation-induced reduction in [Na+]o contributes considerably to the inhibitory effect of elevated [K+]o. In conclusion, excitation-induced passive and active Na+ and K+ fluxes are important causes of muscle fatigue and force recovery, respectively. PMID:25862098

  2. Na-H Exchanger Isoform-2 (NHE2) Mediates Butyrate-dependent Na+ Absorption in Dextran Sulfate Sodium (DSS)-induced Colitis.

    PubMed

    Rajendran, Vazhaikkurichi M; Nanda Kumar, Navalpur S; Tse, Chung M; Binder, Henry J

    2015-10-16

    Diarrhea associated with ulcerative colitis (UC) occurs primarily as a result of reduced Na(+) absorption. Although colonic Na(+) absorption is mediated by both epithelial Na(+) channels (ENaC) and Na-H exchangers (NHE), inhibition of NHE-mediated Na(+) absorption is the primary cause of diarrhea in UC. As there are conflicting observations reported on NHE expression in human UC, the present study was initiated to identify whether NHE isoforms (NHE2 and NHE3) expression is altered and how Na(+) absorption is regulated in DSS-induced inflammation in rat colon, a model that has been used to study UC. Western blot analyses indicate that neither NHE2 nor NHE3 expression is altered in apical membranes of inflamed colon. Na(+) fluxes measured in vitro under voltage clamp conditions in controls demonstrate that both HCO3 (-)-dependent and butyrate-dependent Na(+) absorption are inhibited by S3226 (NHE3-inhibitor), but not by HOE694 (NHE2-inhibitor) in normal animals. In contrast, in DSS-induced inflammation, butyrate-, but not HCO3 (-)-dependent Na(+) absorption is present and is inhibited by HOE694, but not by S3226. These observations indicate that in normal colon NHE3 mediates both HCO3 (-)-dependent and butyrate-dependent Na(+) absorption, whereas DSS-induced inflammation activates NHE2, which mediates butyrate-dependent (but not HCO3 (-)-dependent) Na(+) absorption. In in vivo loop studies HCO3 (-)-Ringer and butyrate-Ringer exhibit similar rates of water absorption in normal rats, whereas in DSS-induced inflammation luminal butyrate-Ringer reversed water secretion observed with HCO3 (-)-Ringer to fluid absorption. Lumen butyrate-Ringer incubation activated NHE3-mediated Na(+) absorption in DSS-induced colitis. These observations suggest that the butyrate activation of NHE2 would be a potential target to control UC-associated diarrhea.

  3. Aquaporin-1 tunes pain perception by interaction with Na(v)1.8 Na+ channels in dorsal root ganglion neurons.

    PubMed

    Zhang, Hua; Verkman, A S

    2010-02-19

    Aquaporin-1 (AQP1) water channels are expressed in the plasma membrane of dorsal root ganglion (DRG) neurons. We found reduced osmotic water permeability in freshly isolated DRG neurons from AQP1(-/-) versus AQP1(+/+) mice. Behavioral studies showed greatly reduced thermal inflammatory pain perception in AQP1(-/-) mice evoked by bradykinin, prostaglandin E(2), and capsaicin as well as reduced cold pain perception. Patch clamp of freshly isolated DRG neurons showed reduced action potential firing in response to current injections. Single action potentials after pulse current injections showed reduced maximum inward current, suggesting impaired Na(v)1.8 Na(+) function. Whole-cell Na(v)1.8 Na(+) currents in Na(v)1.8-expressing ND7-23 cells showed slowed frequency-dependent inactivation after AQP1 transfection. Immunoprecipitation studies showed AQP1- Na(v)1.8 Na(+) interaction, which was verified in live cells by single-particle tracking of quantum dot-labeled AQP1. Our results implicate the involvement of AQP1 in DRG neurons for the perception of inflammatory thermal pain and cold pain, whose molecular basis is accounted for, in part, by reduced Na(v)1.8-dependent membrane Na(+) current. AQP1 is, thus, a novel target for pain management. PMID:20018876

  4. Bundle-like α'-NaV2O5 mesocrystals: from synthesis, growth mechanism to analysis of Na-ion intercalation/deintercalation abilities

    NASA Astrophysics Data System (ADS)

    Liu, Pengcheng; Zhou, Dehua; Zhu, Kongjun; Wu, Qingliu; Wang, Yifeng; Tai, Guoan; Zhang, Wei; Gu, Qilin

    2016-01-01

    Bundle-like α'-NaV2O5 mesocrystals were synthesized successfully by a two-step hydrothermal method. Observations using electron microscopy revealed that the obtained NaV2O5 mesocrystals were composed of nanobelts with the preferential growth direction of [010]. The precise crystal structure was further confirmed by Rietveld refinement and Raman spectroscopy. Based on analysis of crystal structure and microscopy, a reaction and growth mechanism, hydrolysis-condensation (oxolation and olation)-ion exchange-self-assembly, was proposed and described in detail. Furthermore, electrochemical measurements were used to analyze the Na-ions intercalation/deintercalation abilities in NaV2O5, and indicated that Na-ions were difficult to extract. Importantly, the DFT theoretical calculation results, which showed that the migration energy of Na-ions was so huge that migration of Na-ions was quite difficult, can explain and support well the results of the electrochemical measurements.Bundle-like α'-NaV2O5 mesocrystals were synthesized successfully by a two-step hydrothermal method. Observations using electron microscopy revealed that the obtained NaV2O5 mesocrystals were composed of nanobelts with the preferential growth direction of [010]. The precise crystal structure was further confirmed by Rietveld refinement and Raman spectroscopy. Based on analysis of crystal structure and microscopy, a reaction and growth mechanism, hydrolysis-condensation (oxolation and olation)-ion exchange-self-assembly, was proposed and described in detail. Furthermore, electrochemical measurements were used to analyze the Na-ions intercalation/deintercalation abilities in NaV2O5, and indicated that Na-ions were difficult to extract. Importantly, the DFT theoretical calculation results, which showed that the migration energy of Na-ions was so huge that migration of Na-ions was quite difficult, can explain and support well the results of the electrochemical measurements. Electronic supplementary

  5. [Effects of NaCl and Na2CO3 stresses on the growth and photosynthesis characteristics of Morus alba seedlings].

    PubMed

    Zhang, Hui-Hui; Zhang, Xiu-Li; Li, Xin; Ding, Jun-Nan; Zhu, Wen-Xu; Qi, Fei; Zhang, Ting; Tian, Ye; Sun, Guang-Yu

    2012-03-01

    Taking 1-year old Morus alba variety 'Qinglong' seedlings as test materials, this paper studied their growth and photosynthetic characteristics under the stresses of different concentration neutral salt NaCl and alkali salt Na2CO3. Salt stresses decreased the plant height and the leaf number, biomass, and photosynthetic capacity of the seedlings markedly. With increasing concentration Na+, the leaf stomatal conductance, transpiration rate, net photosynthetic rate, actual photochemical efficiency, electron transport rate, and photochemical quenching (qP) decreased obviously, the energy dissipation rate increased, and the light use efficiency and photosynthetic capacity dropped down. At low concentrations Na+ (< 150 mmol x L(-1)), the seedlings growth and leaf photosynthetic capacity were slightly inhibited, and the adaptability of the seedlings to the salt stresses increased via the increase of root/shoot ratio. However, this protection mechanism was impaired by increasing salt concentration. Na2CO3 stress (Na+ concentration > 50 mmol x L(-)) had stronger inhibitory effects on the seedlings growth and leaf photosynthetic capacity, and the effect increased with increasing Na+ concentration. It was concluded that at Na+ concentration < 150 mmol x L(-1), the photosynthetic adaptability of M. alba to neutral salt stress was mainly dependent on the plant morphology and photosynthetic metabolism, but at Na+ concentration > 150 mmol x L(-1), the photosynthetic adaptability of M. alba to alkali salt stress was mainly dependent on the photosynthetic metabolism.

  6. Complex transition metal hydrides incorporating ionic hydrogen: thermal decomposition pathway of Na2Mg2FeH8 and Na2Mg2RuH8.

    PubMed

    Humphries, Terry D; Matsuo, Motoaki; Li, Guanqiao; Orimo, Shin-Ichi

    2015-03-28

    Complex transition metal hydrides have potential technological application as hydrogen storage materials, smart windows and sensors. Recent exploration of these materials has revealed that the incorporation of anionic hydrogen into these systems expands the potential number of viable complexes, while varying the countercation allows for optimisation of their thermodynamic stability. In this study, the optimised synthesis of Na2Mg2TH8 (T = Fe, Ru) has been achieved and their thermal decomposition properties studied by ex situ Powder X-ray Diffraction, Gas Chromatography and Pressure-Composition Isotherm measurements. The temperature and pathway of decomposition of these isostructural compounds differs considerably, with Na2Mg2FeH8 proceeding via NaMgH3 in a three-step process, while Na2Mg2RuH8 decomposes via Mg2RuH4 in a two-step process. The first desorption maxima of Na2Mg2FeH8 occurs at ca. 400 °C, while Na2Mg2RuH8 has its first maxima at 420 °C. The enthalpy and entropy of desorption for Na2Mg2TH8 (T = Fe, Ru) has been established by PCI measurements, with the ΔHdes for Na2Mg2FeH8 being 94.5 kJ mol(-1) H2 and 125 kJ mol(-1) H2 for Na2Mg2RuH8. PMID:25732233

  7. Investigation of influence of NaOH and NaCl activating solutions on bentonite stabilization in suspension fertilizers

    NASA Astrophysics Data System (ADS)

    Hoffmann, Krystyna; Hoffmann, Józef; Mikła, Daniel; Huculak-Mä Czka, Marta; Skut, Jakub

    2010-05-01

    purposes. In this paper research aimed at activating Jaroszów bentonite were presented. 2. MATERIALS AND METHODS The studies on activating clay minerals were carried out using the exchange of Ca2+, K+, Mg2+ ions to Na+ ions. For activation process the NaOH and NaCl solutions of concentrations 0,1M and 2,0M respectively were applied. For the purposes mentioned above 5g of weighed portion of mineral were introduced into four 250 ml conical flasks, two of them were filled with 100 ml of 0,1M and 2.0 M NaOH solution. Two remaining flasks were filled with 100 ml of 0,1M and 2.0 M NaCl solution. The samples preparred acoording to this instructions were shaken for 1 and 8 hours, and subsequently subjected to a vacuum filtration in order to separete solid fraction from filtrate. Mineral which remaied on the filter was dried in temperature of 110oC for 2 hours. 1g of dried mineral was collected for further examinations, mixed with 100 ml of distilled water and poured into the 25 ml measuring cylinder. Then every day for 14 days a change of the volume of deposit, suspension and pure solution above the suspension have been measured. 3. RESULTS DISCUSSION "Jaroszów" bentonite, activated with Na+ ions using 0,1M NaOH solution constitutes the most beneficial agent stabilizing the solid phase in the aqueous environment. The time factor didn't have considerable influence on bentonite activation. Results were similar for 1h as well as 8h. The addition of NaOH sustained suspension on respectively high level, about 80% vol., after 14 measurement days.

  8. Conservation of Na+ vs. K+ by the rat cortical collecting duct.

    PubMed

    Frindt, Gustavo; Houde, Véronique; Palmer, Lawrence G

    2011-07-01

    Regulation of transport by principal cells of the distal nephron contributes to maintenance of Na(+) and K(+) homeostasis. To assess which of these ions is given a higher priority by these cells, we investigated the upregulation of epithelial Na(+) channels (ENaC) in the rat cortical collecting duct (CCD) during Na depletion with and without simultaneous K depletion. ENaC activity, assessed as whole cell amiloride-sensitive current in split-open tubules, was 260 ± 40 pA/cell in K-repleted but virtually undetectable (3 ± 1 pA/cell) in K-depleted animals. This difference was confirmed biochemically by the reduced amounts of the cleaved forms of both the α-ENaC and γ-ENaC subunits measured in immunoblots. In contrast, in K-depleted rats, simultaneously reducing Na intake did not affect the activity of ROMK channels, assessed as tertiapin-Q-sensitive whole cell currents, in the CCDs. The lack of Na current in K-depleted animals was the result of reduced levels of aldosterone in plasma, rather than a reduced sensitivity to the hormone. However, rats on a low-Na, low-K diet for 1 wk did not excrete more Na than those on a low-Na, control-K diet for the same period of time. Immunoblot analysis indicated increased levels of the thiazide-sensitive NaCl cotransporter and the apical Na-H exchanger NHE3. This suggests that with reduced K intake, Na balance is maintained despite reduced aldosterone and Na(+) channel activity by upregulation of Na(+) transport in upstream segments. Under these conditions, Na(+) transport by the aldosterone-sensitive distal nephron is reduced, despite the low-Na intake to minimize K(+) secretion and urinary K losses. PMID:21454253

  9. Conservation of Na+ vs. K+ by the rat cortical collecting duct.

    PubMed

    Frindt, Gustavo; Houde, Véronique; Palmer, Lawrence G

    2011-07-01

    Regulation of transport by principal cells of the distal nephron contributes to maintenance of Na(+) and K(+) homeostasis. To assess which of these ions is given a higher priority by these cells, we investigated the upregulation of epithelial Na(+) channels (ENaC) in the rat cortical collecting duct (CCD) during Na depletion with and without simultaneous K depletion. ENaC activity, assessed as whole cell amiloride-sensitive current in split-open tubules, was 260 ± 40 pA/cell in K-repleted but virtually undetectable (3 ± 1 pA/cell) in K-depleted animals. This difference was confirmed biochemically by the reduced amounts of the cleaved forms of both the α-ENaC and γ-ENaC subunits measured in immunoblots. In contrast, in K-depleted rats, simultaneously reducing Na intake did not affect the activity of ROMK channels, assessed as tertiapin-Q-sensitive whole cell currents, in the CCDs. The lack of Na current in K-depleted animals was the result of reduced levels of aldosterone in plasma, rather than a reduced sensitivity to the hormone. However, rats on a low-Na, low-K diet for 1 wk did not excrete more Na than those on a low-Na, control-K diet for the same period of time. Immunoblot analysis indicated increased levels of the thiazide-sensitive NaCl cotransporter and the apical Na-H exchanger NHE3. This suggests that with reduced K intake, Na balance is maintained despite reduced aldosterone and Na(+) channel activity by upregulation of Na(+) transport in upstream segments. Under these conditions, Na(+) transport by the aldosterone-sensitive distal nephron is reduced, despite the low-Na intake to minimize K(+) secretion and urinary K losses.

  10. Spectrophotometric Investigation of U(VI) Chloride Complexation in the NaCl/NaClO{sub 4} System

    SciTech Connect

    Paviet-Hartmann, P.; Lin, M.R.; Runde, W.H.

    1998-11-30

    Post closure radioactive release scenarios from geologic salt formation, such as the WIPP (Waste Isolation Pilot Plant)(USA) include hydrologic transport of radionuclides through a chloride saturated aquifer. Consequently, the understanding of actinide solution chemistry in brines is essential for modeling requiring accurate knowledge of the interaction between AnO{sub 2}{sup 2+} and chloride ions. Complexation constants of two U(VI) chloride species, UO{sub 2}Cl{sup +} and UO{sub 2}Cl{sub 2}{sup 0}, have been intensively studied for about 40 years using different methods. However, large uncertainties reflect the general difficulty in determining accurate stability constants of weak complexes. In order to model the behavior of U(VI) in brines, we studied the formation of its chloride complexes by UV-Vis spectroscopy as a function of the NaCl concentration at 25 C. The experiments were performed at constant ionic strength by varying the concentration ratio of NaCl and NaClO{sub 4}. Deconvolution resulted in single component absorption spectra for UO{sub 2}Cl{sup +} and UO{sub 2}Cl{sub 2}{sup 0}. The apparent stability constants of UO{sub 2}Cl{sup +} and UO{sub 2}Cl{sub 2}{sup 0} are at different ionic strengths and the experimental data are used to parameterize using the SIT approach.

  11. 18F-NaF PET/CT Imaging of Brain Metastases.

    PubMed

    Salgarello, Matteo; Lunardi, Gianluigi; Inno, Alessandro; Pasetto, Stefano; Severi, Fabrizia; Gorgoni, Giancarlo; Gori, Stefania

    2016-07-01

    F-NaF is a radiopharmaceutical widely used in PET imaging to detect bone metastases. Several cases of F-NaF uptake from brain metastases have been described, but a specific protocol for the evaluation of brain metastases with F-NaF has not been developed yet. Here we report images of F-NaF PET/CT, standard CT, and MRI of a brain metastasis in a patient with non-small lung cancer. Through a dynamic acquisition procedure, we have identified the first minutes after injection as the preferable time point of imaging acquisition for the study of brain metastases with F-NaF.

  12. A single mutation converts bacterial Na(+) -transporting rhodopsin into an H(+) transporter.

    PubMed

    Mamedov, Mahir D; Mamedov, Adalyat M; Bertsova, Yulia V; Bogachev, Alexander V

    2016-09-01

    Na(+) -rhodopsins are light-driven pumps used by marine bacteria to extrude Na(+) ions from the cytoplasm. We show here that replacement of Gln123 on the cytoplasmic side of the ion-conductance channel with aspartate or glutamate confers H(+) transport activity to the Na(+) -rhodopsin from Dokdonia sp. PRO95. The Q123E variant could transport H(+) out of Escherichia coli cells in a medium containing 100 mm Na(+) and SCN(-) as the penetrating anion. The rates of the photocycle steps of this variant were only marginally dependent on Na(+) , and the major electrogenic steps were the decays of the K and O intermediates. PMID:27447358

  13. Structure and electrochemistry of NaFePO{sub 4} and Na{sub 2}FePO{sub 4}F cathode materials prepared via mechanochemical route

    SciTech Connect

    Kosova, N.V.; Podugolnikov, V.R.; Devyatkina, E.T.; Slobodyuk, A.B.

    2014-12-15

    Highlights: • Na{sub 2}FePO{sub 4}F is prepared by mechanochemically assisted solid state synthesis. • The crystal and local structure are studied by XRPD, FTIR, Mössbauer, and NMR. • Na{sup +}/Li{sup +} ion exchange is completed with the formation of NaLiFePO{sub 4}F. • The average D{sub Li} (10{sup −15} cm{sup 2} s{sup −1}) is determined from GITT measurements. - Abstract: Nanostructured NaFePO{sub 4} (space group Pmnb) and Na{sub 2}FePO{sub 4}F (space group Pbcn) were prepared by a quick and facile mechanochemically assisted solid state synthesis. Low-crystalline Na{sub 2}FePO{sub 4}F was formed as a result of direct mechanochemical reaction of NaFePO{sub 4} with NaF. It crystallizes upon subsequent heating to 600 °C and decomposes at higher temperatures. Crystal and local structure were analyzed by XRD using Rietveld refinement, FTIR, Mössbauer, and NMR spectroscopy. Electrochemical properties were studied by galvanostatic cycling in lithium cells and GITT. Although NaFePO{sub 4} showed some electrochemical activity, neither electrochemical nor chemical Na{sup +}/Li{sup +} exchange was observed by XRD. On contrary, electrochemical and chemical Na{sup +}/Li{sup +} ion exchange occurred in the case of Na{sub 2}FePO{sub 4}F and accomplished with the NaLiFePO{sub 4}F formation. Li{sup +} diffusion coefficient in NaLiFePO{sub 4}F at different delithiated/lithiated states was determined from GITT. Carbon-coated Na{sub 2}FePO{sub 4}F shows discharge capacity of 116 mA h g{sup −1} at 0.1 C rate within the 2.0–4.2 V voltage range and a good cyclability.

  14. Synthesis and Near-infrared Luminescent Properties of NaGdF4:Nd3+@NaGdF4 Core/Shell Nanocrystals with Different Shell Thickness.

    PubMed

    Li, Xinke; You, Fangtian; Peng, Hongshang; Huang, Shihua

    2016-04-01

    The near-infrared to near-infrared (NIR-to-NIR) photoluminescence of nanocrystals has outstanding advantages in biological imaging. NaGdF4:Nd3+ core nanocrystals and NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals with different shell thicknesses were synthesized by a simple solvothermal method. The obtained nanocrystals were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The phase of all nanocrystals is hexagonal. NaGdF4:Nd3+ core nanocrystals have an average size of 6 nm. By controlling core-shell ratio for 1:2 and 1:3, we obtained NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals with average sizes of 10 nm and 11 nm, respectively. When excited at 808 nm, strong NIR emission was observed. The emission peaks at -860 nm, -1060 nm and -1330 nm correspond to the transitions from the 4F3/2 state to the 4I9/2, 4I1/2 and 4I13/2 state of Nd3+ ions, respectively. The emission intensity of NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals is stronger than that of the core. The intensity increases with the increase of shell thickness. The shell improves the luminous efficiency by reducing surface defects. The decay time of Nd3+ emission in NaGdF4:Nd3+@NaGdF4 core/shell nanocrystal is longer than that in NaGdF4:Nd3+ core, indicating that the shell isolates effectively the emitting ions (Nd3+) from the quenching defects. With the increase of shell thickness, the decay time becomes longer. Within a certain range of shell thickness, thicker shell can protect the emitting Nd3+ ions on the surface of core nanocrystals more effectively.

  15. [Absorption and allocation characteristics of K+, Ca2+, Na+ and Cl- in different organs of Broussonetia papyrifera seedlings under NaCl stress].

    PubMed

    Yang, Fan; Ding, Fei; Du, Tian-Zhen

    2009-04-01

    One-year-old Broussonetia papyrifera seedlings were subjected to 0.4, 1, 2, 3, and 4 g x kg(-1) of soil NaCl stress, and their biomass accumulation, leaf plasma membrane permeability, and the absorption, allocation and translocation of K+, Ca2+, Na+, and Cl-, as well as the symptoms of salt injury, were studied and investigated. The leaf plasma membrane permeability increased with the increase of soil NaCl concentration and of the duration of soil NaCl stress, and the seedling's root/shoot ratio also increased with increasing soil NaCl concentration. When the soil NaCl concentration exceeded 3 g x kg(-1), leaf plasma membrane permeability and seedling' s biomass accumulation were affected significantly. The Na+ and Cl- concentrations in different organs of seedlings increased with increasing soil NaCl concentration while the K+ and Ca2+ concentrations were in adverse, and the ion contents in leaves were always much higher than those in other organs, illustrating that soil NaCl stress affected the K+ and Ca2+ absorbing capability of roots, and inhibited the selective translocation of K+ and Ca2+ to aboveground parts. As a result, the K+ and Ca2+ concentrations in leaves and stems decreased. The study showed that B. papyrifera could effectively resist the injury of osmotic stress from soil salt via absorbing and accumulating Na+ and Cl-, but excessive accumulation of Na+ and Cl- could induce salt toxicity. As a non-halophyte species with relatively strong salt resistance, the aboveground parts of B. papyrifera did not have significant salt-exclusion effect.

  16. Synthesis and Near-infrared Luminescent Properties of NaGdF4:Nd3+@NaGdF4 Core/Shell Nanocrystals with Different Shell Thickness.

    PubMed

    Li, Xinke; You, Fangtian; Peng, Hongshang; Huang, Shihua

    2016-04-01

    The near-infrared to near-infrared (NIR-to-NIR) photoluminescence of nanocrystals has outstanding advantages in biological imaging. NaGdF4:Nd3+ core nanocrystals and NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals with different shell thicknesses were synthesized by a simple solvothermal method. The obtained nanocrystals were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The phase of all nanocrystals is hexagonal. NaGdF4:Nd3+ core nanocrystals have an average size of 6 nm. By controlling core-shell ratio for 1:2 and 1:3, we obtained NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals with average sizes of 10 nm and 11 nm, respectively. When excited at 808 nm, strong NIR emission was observed. The emission peaks at -860 nm, -1060 nm and -1330 nm correspond to the transitions from the 4F3/2 state to the 4I9/2, 4I1/2 and 4I13/2 state of Nd3+ ions, respectively. The emission intensity of NaGdF4:Nd3+@NaGdF4 core/shell nanocrystals is stronger than that of the core. The intensity increases with the increase of shell thickness. The shell improves the luminous efficiency by reducing surface defects. The decay time of Nd3+ emission in NaGdF4:Nd3+@NaGdF4 core/shell nanocrystal is longer than that in NaGdF4:Nd3+ core, indicating that the shell isolates effectively the emitting ions (Nd3+) from the quenching defects. With the increase of shell thickness, the decay time becomes longer. Within a certain range of shell thickness, thicker shell can protect the emitting Nd3+ ions on the surface of core nanocrystals more effectively. PMID:27451742

  17. Na+ and Cl(-) ions show additive effects under NaCl stress on induction of oxidative stress and the responsive antioxidative defense in rice.

    PubMed

    Khare, Tushar; Kumar, Vinay; Kishor, P B Kavi

    2015-07-01

    Despite the fact that when subjected to salinity stress most plants accumulate high concentrations of sodium (Na(+)) and chloride (Cl(-)) ions in their tissues, major research has however been focused on the toxic effects of Na(+). Consequently, Cl(-) toxicity mechanisms in annual plants, particularly in inducing oxidative stress, are poorly understood. Here, the extent to which Na(+) and/or Cl(-) ions contribute in inducing oxidative stress and regulating the adaptive antioxidant defense is shown in two Indica rice genotypes differing in their salt tolerance. Equimolar (100 mM) concentrations of Na(+), Cl(-), and NaCl (EC ≈ 10 dS m(-1)) generated free-radical (O2 (•-), (•)OH) and non-radical (H2O2) forms of reactive oxygen species (ROS) and triggered cell death in leaves of 21-day-old hydroponically grown rice seedlings as evident by spectrophotometric quantifications and histochemical visualizations. The magnitude of ROS-mediated oxidative damage was higher in sensitive cultivar, whereas NaCl proved to be most toxic among the treatments. Salt treatments significantly increased activities of antioxidant enzymes and their isozymes including superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase. Na(+) and Cl(-) ions showed additive effects under NaCl in activating the antioxidant enzyme machinery, and responses were more pronounced in tolerant cultivar. The expression levels of SodCc2, CatA, and OsPRX1 genes were largely consistent with the activities of their corresponding enzymes. Salt treatments caused an imbalance in non-enzymatic antioxidants ascorbic acid, α-tocopherol, and polyphenols, with greater impacts under NaCl than Na(+) and Cl(-) separately. Results revealed that though Cl(-) was relatively less toxic than its counter-cation, its effects cannot be totally ignored. Both the cultivars responded in the same manner, but the tolerant cultivar maintained lower Na(+)/K(+) and ROS levels coupled with better

  18. Composite PEOn:NaTFSI polymer electrolyte: Preparation, thermal and electrochemical characterization

    NASA Astrophysics Data System (ADS)

    Serra Moreno, J.; Armand, M.; Berman, M. B.; Greenbaum, S. G.; Scrosati, B.; Panero, S.

    2014-02-01

    Membranes of sodium bis(trifluoromethanesulfonate) imide (NaTFSI) complexed with poly(ethylene oxide) (PEO) salt have been prepared by a solvent-free hot-pressing technique with different EO:Na molar ratio. All membranes show good ionic conductivities in the range of 10-3 S cm-1 above 70 °C. However, the more NaTFSI-concentrated samples are sticky gums due to the plasticizing nature of the anion. The PEO20:NaTFSI sample exhibits the compromise of conductivity, thermal and mechanical properties. The addition of nanometric SiO2 to the PEO20:NaTFSI membranes further enhances their mechanical properties. Moreover, the PEO20:NaTFSI + 5 wt.% SiO2 membranes show similar ionic conductivity and similar anodic electrochemical stability in comparison to the ceramic free PEO20:NaTFSI sample. In a Na(s)/polymer electrolyte/Na(s) symmetrical cell followed up to 30 days, the presence of the ceramic filler slightly increased the interface resistance in comparison to the ceramic-free membrane. Nuclear magnetic resonance determinations of anion diffusion coefficients and Na+ mobility suggest that presence of filler may have a positive affect on the cation transference number that is in accordance with the tNa+ transference number measurement.

  19. Phosphorene as an anode material for Na-ion batteries: a first-principles study.

    PubMed

    Kulish, Vadym V; Malyi, Oleksandr I; Persson, Clas; Wu, Ping

    2015-06-01

    We systematically investigate a novel two-dimensional nanomaterial, phosphorene, as an anode for Na-ion batteries. Using first-principles calculations, we determine the Na adsorption energy, specific capacity and Na diffusion barriers on monolayer phosphorene. We examine the main trends in the electronic structure and mechanical properties as a function of Na concentration. We find a favorable Na-phosphorene interaction with a high theoretical Na storage capacity. We find that Na-phosphorene undergoes semiconductor-metal transition at high Na concentration. Our results show that Na diffusion on phosphorene is fast and anisotropic with an energy barrier of only 0.04 eV. Owing to its high capacity, good stability, excellent electrical conductivity and high Na mobility, monolayer phosphorene is a very promising anode material for Na-ion batteries. The calculated performance in terms of specific capacity and diffusion barriers is compared to other layered 2D electrode materials, such as graphene, MoS2, and polysilane.

  20. Structural Properties and Phase Transition of Na Adsorption on Monolayer MoS2.

    PubMed

    He, Hai; Lu, Pengfei; Wu, Liyuan; Zhang, Chunfang; Song, Yuxin; Guan, Pengfei; Wang, Shumin

    2016-12-01

    First-principles calculations are performed to investigate the structural stability of Na adsorption on 1H and 1T phases of monolayer MoS2. Our results demonstrate that it is likely to make the stability of distorted 1T phase of MoS2 over the 1H phase through adsorption of Na atoms. The type of distortion depends on the concentration of adsorbed Na atoms and changes from zigzag-like to diamond-like with the increasing of adsorbed Na atom concentrations. Our calculations show that the phase transition from 1H-MoS2 to 1T-MoS2 can be obtained by Na adsorption. We also calculate the electrochemical properties of Na adsorption on MoS2 monolayer. These results indicate that MoS2 is one of potential negative electrodes for Na-ion batteries. PMID:27416903

  1. Salt and gene expression: evidence for [Na+]i/[K+]i-mediated signaling pathways.

    PubMed

    Orlov, Sergei N; Hamet, Pavel

    2015-03-01

    Our review focuses on the recent data showing that gene transcription and translation are under the control of signaling pathways triggered by modulation of the intracellular sodium/potassium ratio ([Na+]i/[K+]i). Side-by-side with sensing of osmolality elevation by tonicity enhancer-binding protein (TonEBP, NFAT5), [Na+]i/[K+]i-mediated excitation-transcription coupling may contribute to the transcriptomic changes evoked by high salt consumption. This novel mechanism includes the sensing of heightened Na+ concentration in the plasma, interstitial, and cerebrospinal fluids via augmented Na+ influx in the endothelium, immune system cells, and the subfornical organ, respectively. In these cells, [Na+]i/[K+]i ratio elevation, triggered by augmented Na+ influx, is further potentiated by increased production of endogenous Na+,K+-ATPase inhibitors documented in salt-sensitive hypertension. PMID:25479826

  2. Structural Properties and Phase Transition of Na Adsorption on Monolayer MoS2

    NASA Astrophysics Data System (ADS)

    He, Hai; Lu, Pengfei; Wu, Liyuan; Zhang, Chunfang; Song, Yuxin; Guan, Pengfei; Wang, Shumin

    2016-07-01

    First-principles calculations are performed to investigate the structural stability of Na adsorption on 1H and 1T phases of monolayer MoS2. Our results demonstrate that it is likely to make the stability of distorted 1T phase of MoS2 over the 1H phase through adsorption of Na atoms. The type of distortion depends on the concentration of adsorbed Na atoms and changes from zigzag-like to diamond-like with the increasing of adsorbed Na atom concentrations. Our calculations show that the phase transition from 1H-MoS2 to 1T-MoS2 can be obtained by Na adsorption. We also calculate the electrochemical properties of Na adsorption on MoS2 monolayer. These results indicate that MoS2 is one of potential negative electrodes for Na-ion batteries.

  3. Structural Properties and Phase Transition of Na Adsorption on Monolayer MoS2.

    PubMed

    He, Hai; Lu, Pengfei; Wu, Liyuan; Zhang, Chunfang; Song, Yuxin; Guan, Pengfei; Wang, Shumin

    2016-12-01

    First-principles calculations are performed to investigate the structural stability of Na adsorption on 1H and 1T phases of monolayer MoS2. Our results demonstrate that it is likely to make the stability of distorted 1T phase of MoS2 over the 1H phase through adsorption of Na atoms. The type of distortion depends on the concentration of adsorbed Na atoms and changes from zigzag-like to diamond-like with the increasing of adsorbed Na atom concentrations. Our calculations show that the phase transition from 1H-MoS2 to 1T-MoS2 can be obtained by Na adsorption. We also calculate the electrochemical properties of Na adsorption on MoS2 monolayer. These results indicate that MoS2 is one of potential negative electrodes for Na-ion batteries.

  4. Preparation of zeolite NaA for CO2 capture from nickel laterite residue

    NASA Astrophysics Data System (ADS)

    Du, Tao; Liu, Li-ying; Xiao, Penny; Che, Shuai; Wang, He-ming

    2014-08-01

    Zeolite NaA was successfully prepared from nickel laterite residue for the first time via a fusion-hydrothermal procedure. The structure and morphology of the as-synthesized zeolite NaA were characterized with a range of experimental techniques, such as X-ray diffraction, scanning electronic microscopy, and infrared spectroscopy. It was revealed that the structures of the produced zeolites were dependent on the molar ratios of the reactants and hydrothermal reaction conditions, so the synthesis conditions were optimized to obtain pure zeolite NaA. Adsorption of nitrogen and carbon dioxide on the prepared zeolite NaA was also measured and analyzed. The results showed that zeolite NaA could be prepared with reasonable purity, it had physicochemical properties comparable with zeolite NaA made from other methods, and it had excellent gas adsorption properties, thus demonstrating that zeolite NaA could be prepared from nickel laterite residue.

  5. EXPRESS: Voltage-dependent sodium (NaV) channels in group IV sensory afferents.

    PubMed

    Ramachandra, Renuka; Elmslie, Keith S

    2016-01-01

    Patients with intermittent claudication suffer from both muscle pain and an exacerbated exercise pressor reflex. Excitability of the group III and group IV afferent fibers mediating these functions is controlled in part by voltage-dependent sodium (NaV) channels. We previously found tetrodotoxin-resistant NaV1.8 channels to be the primary type in muscle afferent somata. However, action potentials in group III and IV afferent axons are blocked by TTX, supporting a minimal role of NaV1.8 channels. To address these apparent differences in NaV channel expression between axon and soma, we used immunohistochemistry to identify the NaV channels expressed in group IV axons within the gastrocnemius muscle and the dorsal root ganglia sections. Positive labeling by an antibody against the neurofilament protein peripherin was used to identify group IV neurons and axons. We show that >67% of group IV fibers express NaV1.8, NaV1.6, or NaV1.7. Interestingly, expression of NaV1.8 channels in group IV somata was significantly higher than in the fibers, whereas there were no significant differences for either NaV1.6 or NaV1.7. When combined with previous work, our results suggest that NaV1.8 channels are expressed in most group IV axons, but that, under normal conditions, NaV1.6 and/or NaV1.7 play a more important role in action potential generation to signal muscle pain and the exercise pressor reflex. PMID:27385723

  6. Na/sup +/-K/sup +/ pump in chronic renal failure

    SciTech Connect

    Deepak, K.; Kahn, T.

    1987-05-01

    This review summarizes the evidence for the defect in Na/sup +/-K/sup +/ pump in chronic renal failure, considers the role of various factors in causing this defect, and discusses the clinical implications thereof. Intracellular Na is elevated in erythrocytes, leukocytes, and muscle cells from some patients with chronic renal failure (CRF). Recent evidence suggest that this elevation of cell Na may be, in large part, a consequence of decreased number of Na/sup +/-K/sup +/ pump units per cell. Maintenance dialysis over a period of weeks ameliorates the defect in intracellular Na/sup +/, and this improvement is contemporaneous with an increase in the number of Na/sup +/-K/sup +/ pump sites per cell. In erythrocytes with normal cell Na/sup +/, acute hemodialysis increases the rate of /sup 22/Na/sup +/ and /sup 42/K/sup +/ transport. Many factors such as the presence of retained toxic metabolite or circulating inhibitor in the uremic plasma, or biochemical changes produced by acute hemodialysis, may explain this finding. In cells with high cell Na/sup +/, the pump-mediated /sup 42/K/sup +/ transport is normalized at the expense of a raised cell Na/sup +/. The decreased muscle membrane potential in uremic subjects has been attributed to a decreased activity of Na/sup +/-K/sup +/ pump. The authors discuss the role of hormonal abnormalities and circulating inhibitors, which may cause an acute inhibition of the pump and of other factors such as K/sup +/ depletion, which may cause more chronic alterations. The implications of alteration of Na/sup +/ and K/sup +/ pump transport and raised cell Na/sup +/ on other non-pump-mediated transport pathways are discussed. Raised cell Na/sup +/ may be a marker for the adequacy of maintenance dialysis in patients with end-stage renal failure.

  7. Do Src Kinase and Caveolin Interact Directly with Na,K-ATPase?

    PubMed

    Yosef, Eliyahu; Katz, Adriana; Peleg, Yoav; Mehlman, Tevie; Karlish, Steven J D

    2016-05-27

    Much evidence points to a role of Na,K-ATPase in ouabain-dependent signal transduction. Based on experiments with different cell lines and native tissue membranes, a current hypothesis postulates direct interactions between the Na,K-ATPase and Src kinase (non-receptor tyrosine kinase). Na,K-ATPase is proposed to bind Src kinase and inhibit its activity, whereas ouabain, the specific Na,K-ATPase inhibitor, binds and stabilizes the E2 conformation, thus exposing the Src kinase domain and its active site Tyr-418 for activation. Ouabain-dependent signaling is thought to be mediated within caveolae by a complex consisting of Na,K-ATPase, caveolin, and Src kinase. In the current work, we have looked for direct interactions utilizing purified recombinant Na,K-ATPase (human α1β1FXYD1 or porcine α1D369Nβ1FXYD1) and purified human Src kinase and human caveolin 1 or interactions between these proteins in native membrane vesicles isolated from rabbit kidney. By several independent criteria and techniques, no stable interactions were detected between Na,K-ATPase and purified Src kinase. Na,K-ATPase was found to be a substrate for Src kinase phosphorylation at Tyr-144. Clear evidence for a direct interaction between purified human Na,K-ATPase and human caveolin was obtained, albeit with a low molar stoichiometry (1:15-30 caveolin 1/Na,K-ATPase). In native renal membranes, a specific caveolin 14-5 oligomer (95 kDa) was found to be in direct interaction with Na,K-ATPase. We inferred that a small fraction of the renal Na,K-ATPase molecules is in a ∼1:1 complex with a caveolin 14-5 oligomer. Thus, overall, whereas a direct caveolin 1/Na,K-ATPase interaction is confirmed, the lack of direct Src kinase/Na,K-ATPase binding requires reassessment of the mechanism of ouabain-dependent signaling.

  8. The gasotransmitter hydrogen sulphide decreases Na+ transport across pulmonary epithelial cells

    PubMed Central

    Althaus, M; Urness, KD; Clauss, WG; Baines, DL; Fronius, M

    2012-01-01

    BACKGROUND AND PURPOSE The transepithelial absorption of Na+ in the lungs is crucial for the maintenance of the volume and composition of epithelial lining fluid. The regulation of Na+ transport is essential, because hypo- or hyperabsorption of Na+ is associated with lung diseases such as pulmonary oedema or cystic fibrosis. This study investigated the effects of the gaseous signalling molecule hydrogen sulphide (H2S) on Na+ absorption across pulmonary epithelial cells. EXPERIMENTAL APPROACH Ion transport processes were electrophysiologically assessed in Ussing chambers on H441 cells grown on permeable supports at air/liquid interface and on native tracheal preparations of pigs and mice. The effects of H2S were further investigated on Na+ channels expressed in Xenopus oocytes and Na+/K+-ATPase activity in vitro. Membrane abundance of Na+/K+-ATPase was determined by surface biotinylation and Western blot. Cellular ATP concentrations were measured colorimetrically, and cytosolic Ca2+ concentrations were measured with Fura-2. KEY RESULTS H2S rapidly and reversibly inhibited Na+ transport in all the models employed. H2S had no effect on Na+ channels, whereas it decreased Na+/K+-ATPase currents. H2S did not affect the membrane abundance of Na+/K+-ATPase, its metabolic or calcium-dependent regulation, or its direct activity. However, H2S inhibited basolateral calcium-dependent K+ channels, which consequently decreased Na+ absorption by H441 monolayers. CONCLUSIONS AND IMPLICATIONS H2S impairs pulmonary transepithelial Na+ absorption, mainly by inhibiting basolateral Ca2+-dependent K+ channels. These data suggest that the H2S signalling system might represent a novel pharmacological target for modifying pulmonary transepithelial Na+ transport. PMID:22352810

  9. Na+/H+ Exchange Activity in the Plasma Membrane of Arabidopsis1

    PubMed Central

    Qiu, Quan-Sheng; Barkla, Bronwyn J.; Vera-Estrella, Rosario; Zhu, Jian-Kang; Schumaker, Karen S.

    2003-01-01

    In plants, Na+/H+ exchangers in the plasma membrane are critical for growth in high levels of salt, removing toxic Na+ from the cytoplasm by transport out of the cell. The molecular identity of a plasma membrane Na+/H+ exchanger in Arabidopsis (SOS1) has recently been determined. In this study, immunological analysis provided evidence that SOS1 localizes to the plasma membrane of leaves and roots. To characterize the transport activity of this protein, purified plasma membrane vesicles were isolated from leaves of Arabidopsis. Na+/H+ exchange activity, monitored as the ability of Na to dissipate an established pH gradient, was absent in plants grown without salt. However, exchange activity was induced when plants were grown in 250 mm NaCl and increased with prolonged salt exposure up to 8 d. H+-coupled exchange was specific for Na, because chloride salts of other monovalent cations did not dissipate the pH gradient. Na+/H+ exchange activity was dependent on Na (substrate) concentration, and kinetic analysis indicated that the affinity (apparent Km) of the transporter for Na+ is 22.8 mm. Data from two experimental approaches supports electroneutral exchange (one Na+ exchanged for one proton): (a) no change in membrane potential was measured during the exchange reaction, and (b) Na+/H+ exchange was unaffected by the presence or absence of a membrane potential. Results from this research provide a framework for future studies into the regulation of the plant plasma membrane Na+/H+ exchanger and its relative contribution to the maintenance of cellular Na+ homeostasis during plant growth in salt. PMID:12805632

  10. Na,K-ATPase activity in mouse muscle is regulated by AMPK and PGC-1α.

    PubMed

    Ingwersen, Maria S; Kristensen, Michael; Pilegaard, Henriette; Wojtaszewski, Jørgen F P; Richter, Erik A; Juel, Carsten

    2011-07-01

    Na,K-ATPase activity, which is crucial for skeletal muscle function, undergoes acute and long-term regulation in response to muscle activity. The aim of the present study was to test the hypothesis that AMP kinase (AMPK) and the transcriptional coactivator PGC-1α are underlying factors in long-term regulation of Na,K-ATPase isoform (α,β and PLM) abundance and Na(+) affinity. Repeated treatment of mice with the AMPK activator AICAR decreased total PLM protein content but increased PLM phosphorylation, whereas the number of α- and β-subunits remained unchanged. The K(m) for Na(+) stimulation of Na,K-ATPase was reduced (higher affinity) after AICAR treatment. PLM abundance was increased in AMPK kinase-dead mice compared with control mice, but PLM phosphorylation and Na,K-ATPase Na(+) affinity remained unchanged. Na,K-ATPase activity and subunit distribution were also measured in mice with different degrees of PGC-1α expression. Protein abundances of α1 and α2 were reduced in PGC-1α +/- and -/- mice, and the β(1)/β(2) ratio was increased with PGC-1α overexpression (TG mice). PLM protein abundance was decreased in TG mice, but phosphorylation status was unchanged. Na,K-ATPase V (max) was decreased in PCG-1α TG and KO mice. Experimentally in vitro induced phosphorylation of PLM increased Na,K-ATPase Na(+) affinity, confirming that PLM phosphorylation is important for Na,K-ATPase function. In conclusion, both AMPK and PGC-1α regulate PLM abundance, AMPK regulates PLM phosphorylation and PGC-1α expression influences Na,K-ATPase α(1) and α(2) content and β(1)/β(2) isoform ratio. Phosphorylation of the Na,K-ATPase subunit PLM is an important regulatory mechanism.

  11. Voltage-dependent sodium (NaV) channels in group IV sensory afferents

    PubMed Central

    Elmslie, Keith S

    2016-01-01

    Patients with intermittent claudication suffer from both muscle pain and an exacerbated exercise pressor reflex. Excitability of the group III and group IV afferent fibers mediating these functions is controlled in part by voltage-dependent sodium (NaV) channels. We previously found tetrodotoxin-resistant NaV1.8 channels to be the primary type in muscle afferent somata. However, action potentials in group III and IV afferent axons are blocked by TTX, supporting a minimal role of NaV1.8 channels. To address these apparent differences in NaV channel expression between axon and soma, we used immunohistochemistry to identify the NaV channels expressed in group IV axons within the gastrocnemius muscle and the dorsal root ganglia sections. Positive labeling by an antibody against the neurofilament protein peripherin was used to identify group IV neurons and axons. We show that >67% of group IV fibers express NaV1.8, NaV1.6, or NaV1.7. Interestingly, expression of NaV1.8 channels in group IV somata was significantly higher than in the fibers, whereas there were no significant differences for either NaV1.6 or NaV1.7. When combined with previous work, our results suggest that NaV1.8 channels are expressed in most group IV axons, but that, under normal conditions, NaV1.6 and/or NaV1.7 play a more important role in action potential generation to signal muscle pain and the exercise pressor reflex. PMID:27385723

  12. Potentiodynamic and galvanostatic testing of NaFe0.95V0.05PO4/C composite in aqueous NaNO3 solution, and the properties of aqueous Na1.2V3O8/NaNO3/NaFe0.95V0.05PO4/C battery

    NASA Astrophysics Data System (ADS)

    Vujković, Milica; Mentus, Slavko

    2016-09-01

    The NaFe0.95V0.05PO4/C composite is synthesized by electrochemical ion displacement from LiFe0.95V0.05PO4/C composite in aqueous NaNO3 solution. A coulombic capacity amounting to ∼105 and ∼82 mAh g-1 at sodiation/desodiation rate of 500 and 5000 mAg-1, respectively, is evidenced. For the sake of comparison the same investigations is performed with LiFe0.95V0.05PO4/C composite in LiNO3 solution, and better capacity retention and rate performance is evidenced for NaFe0.95V0.05PO4/C one. This advancement is found to be due a higher participation of pseudocapacity in the sodiation/desodiation charge storage process. An aqueous battery composed of NaFe0.95V0.05PO4/C cathode, belt-like Na1.2V3O8 anode and NaNO3 solution as an electrolyte, tested galvanostatically, displays long-life performance with only 10% of capacity fade after 1000 charge/discharge cycles.

  13. Modulation of the Na,K-pump function by beta subunit isoforms

    PubMed Central

    1994-01-01

    To study the role of the Na,K-ATPase beta subunit in the ion transport activity, we have coexpressed the Bufo alpha 1 subunit (alpha 1) with three different isotypes of beta subunits, the Bufo Na,K-ATPase beta 1 (beta 1NaK) or beta 3 (beta 3NaK) subunit or the beta subunit of the rabbit gastric H,K-ATPase (beta HK), by cRNA injection in Xenopus oocyte. We studied the K+ activation kinetics by measuring the Na,K- pump current induced by external K+ under voltage clamp conditions. The endogenous oocyte Na,K-ATPase was selectively inhibited, taking advantage of the large difference in ouabain sensitivity between Xenopus and Bufo Na,K pumps. The K+ half-activation constant (K1/2) was higher in the alpha 1 beta 3NaK than in the alpha 1 beta 1NaK groups in the presence of external Na+, but there was no significant difference in the absence of external Na+. Association of alpha 1 and beta HK subunits produced active Na,K pumps with a much lower apparent affinity for K+ both in the presence and in the absence of external Na+. The voltage dependence of the K1/2 for external K+ was similar with the three beta subunits. Our results indicate that the beta subunit has a significant influence on the ion transport activity of the Na,K pump. The small structural differences between the beta 1NaK and beta 3NaK subunits results in a difference of the apparent affinity for K+ that is measurable only in the presence of external Na+, and thus appears not to be directly related to the K+ binding site. In contrast, association of an alpha 1 subunit with a beta HK subunit results in a Na,K pump in which the K+ binding or translocating mechanisms are altered since the apparent affinity for external K+ is affected even in the absence of external Na+. PMID:8057080

  14. Ab initio cluster study of crystalline NaF

    SciTech Connect

    Temple, D.K.

    1992-01-01

    A highly-accurate ab initio cluster model of crystalline NaF has been constructed to explore the limits of cluster methods in the treatment of ionic solids. The focus of this model was the characterization of the lattice environment and its influence on the easily-polarizable fluorine anion. The model consisted of a central all-electron fluorine anion coordinated by pseudopotentials, to represent the nearest-neighbor sodium cations, and a finite array of point charges chosen to generate the correct crystal field from the surrounding infinite ionic lattice. The wavefunction and properties of the anion were calculated using the restricted Hartree-Fock and configuration interaction techniques from quantum chemistry. An extensive analysis of basis set incompleteness errors in the anion wavefunction was performed. Important features were identified in the embedded anion, such as its distortion under the influence of the lattice compressions, its stabilization from the Madelung potential, and its changes in size due to electron correlations. Bulk properties of the rocksalt-structure (B1) NaF crystal were derived from the total mode energies, calculated as a function of the crystal volume. The properties included the zero-pressure lattice constant, cohesive energy, and bulk modulus, and the pressure-volume equation-of-state. A series of test calculations explored the relationships, and their underlying physical mechanisms, between the features of the embedded anion and the bulk properties of the crystal. These features often produced opposing changes in the properties, demonstrating the importance of a thorough and systematic treatment of the embedded anion. The most thorough test calculation gave bulk properties that were within 1% of experiment. Using an embedded anion model for the high-pressure cesium-chloride (B2) phase of NaF, the B1-to-B2 structural transition was correctly predicted at 25 GPa, in excellent agreement with the experimental values of 23 to 27 GPa.

  15. Rechargeable Na/Na[sub x]CoO[sub 2] and Na[sub 15]Pb[sub 4]/Na[sub x]CoO[sub 2] polymer electrolyte cells

    SciTech Connect

    Ma, Yanping; Doeff, M.M.; Visco, S.J.; Jonghe, L.C. De . Materials Sciences Div.)

    1993-10-01

    Cells using polyethylene oxide as a sodium ion conducting electrolyte, P2 phase Na[sub x]CoO[sub 2] as the positive electrode and either sodium or sodium/lead alloy as the negative electrode were assembled, discharged, and cycled. Na[sub x]CoO[sub 2] intercalates sodium over a range of x = 0.3--0.9, giving theoretical energy densities of 1,600 Wh/liter (for sodium) or 1,470 Wh/liter (for sodium/lead alloy). Cells could be discharged at rates up to 2.5 mA/cm[sup 2] corresponding to 25% depth of discharge and typically were discharged and charged at 0.5 mA/cm[sup 2] (100% depth of discharge) or approximately 1--2 C rate. Over one hundred cycles to 60% utilization or more, and two hundred shallower cycles at this rate have been obtained in this laboratory. Experimental evidence suggests that the cathode is the limiting factor in determining cycle life and not the Na/PEO interface as previously thought. Estimates of practical energy and power densities based on the cell performance and the following configuration are presented: 30--45 w/o electroactive material in the positive electrode, a twofold excess of sodium, 10 [mu]m separators, and 5 [mu]m current collectors composed of metal coated plastic. On the basis of these calculations, practical power densities of 335 W/liter for continuous discharge at 0.5 mA/cm[sup 2] and up to 2.7 kW/liter for short periods of time should be attainable. This level of performance approaches or exceeds that seen for some lithium/polymer systems under consideration for electric vehicle applications, but with a lower anticipated cost.

  16. Situação da Mulher na Astronomia Brasileira

    NASA Astrophysics Data System (ADS)

    Silva, Adriana V. R.

    2007-07-01

    O conteúdo desse texto surgiu de uma apresentação de mesmo título que fiz na XXXI Reunião Anual da Sociedade Astronômica Brasileira (SAB) em 2005. Esse tema foi inspirado originalmente pela minha participação no "2nd UIPAP International Conference on Women in Physics" realizado entre 23 e 25 de maio de 2005 no Rio de Janeiro. Essa é uma conferência internacional que acontece de três em três anos, sendo que a primeira ocorreu em 2002 na cidade de Paris, França. Participei dessa conferência como membro da delegação da Sociedade Brasileira de Física e um dos trabalhos que apresentei versava sobre a situação das mulheres na Astronomia brasileira, cujos resultados principais discorro a seguir. A situação das astrônomas, baseada nos dados dos sócios da SAB coletados no final de 2004, é comparada com a das físicas brasileiras e também com as nossas colegas americanas. Os dados identificam ainda uma maior evasão da carreira por parte das mulheres do que os homens. Alguns dos possíveis motivos da evasão são discutidos, como o desejo de constituir família e/ou isolamento. Resultados um tanto preocupantes com relação à distribuição de bolsas de produtividade do CNPq também são apresentados. As principais discussões e estratégias recomendadas nesse congresso são mencionadas de forma resumida ao final.

  17. Composition and evolution of the solid-electrolyte interphase in Na2Ti3O7 electrodes for Na-ion batteries: XPS and Auger parameter analysis.

    PubMed

    Muñoz-Márquez, Miguel A; Zarrabeitia, Maider; Castillo-Martínez, Elizabeth; Eguía-Barrio, Aitor; Rojo, Teófilo; Casas-Cabanas, Montse

    2015-04-15

    Na2Ti3O7 is considered a promising negative electrode for Na-ion batteries; however, poor capacity retention has been reported and the stability of the solid-electrolyte interphase (SEI) could be one of the main actors of this underperformance. The composition and evolution of the SEI in Na2Ti3O7 electrodes is hereby studied by means of X-ray photoelectron spectroscopy (XPS). To overcome typical XPS limitations in the photoelectron energy assignments, the analysis of the Auger parameter is here proposed for the first time in battery materials characterization. We have found that the electrode/electrolyte interface formed upon discharge, mostly composed by carbonates and semicarbonates (Na2CO3, NaCO3R), fluorides (NaF), chlorides (NaCl) and poly(ethylene oxide)s, is unstable upon electrochemical cycling. Additionally, solid state nuclear magnetic resonance (NMR) studies prove the reaction of the polyvinylidene difluoride (PVdF) binder with sodium. The powerful approach used in this work, namely Auger parameter study, enables us to correctly determine the composition of the electrode surface layer without any interference from surface charging or absolute binding energy calibration effects. As a result, the suitability for Na-ion batteries of binders and electrolytes widely used for Li-ion batteries is questioned here.

  18. Paramagnetism and improved upconversion luminescence properties of NaYF4:Yb,Er/NaGdF4 nanocomposites synthesized by a boiling water seed-mediated route

    NASA Astrophysics Data System (ADS)

    Yang, Chao-Qing; Li, Ao-Ju; Guo, Wei; Tian, Peng-Hua; Yu, Xiao-Long; Liu, Zhong-Xin; Cao, Yang; Sun, Zhong-Liang

    2016-03-01

    In a route boiling water served as reaction medium, a stoichiometric amount of rare-earth compound and fluoride are put into this system to form α-NaYF4:Yb, Er nuclei. Then prepared sample is heated at elevated temperature to improve the fluorescence intensity, and next a NaGdF4 shell grows on the surface of NaYF4 nuclei. NaYF4:Yb,Er/NaGdF4 core-shell structured upconversion nanoparticles (CSUCNPs) have been successfully synthesized by above route. The use of boiling water decreases the cubic-to-hexagonal phase transition temperature of NaYF4:Yb,Er to 350°C and increases its upconversion (UC) luminescence intensity. A heterogeneous NaGdF4 epitaxially growing on the surface of Ln3+-doped NaYF4 not only improves UC luminescence, but also creates a paramagnetic shell, which can be used as contrast agents in magnetic resonance imaging (MRI). The solution of CSUCNPs shows bright green UC fluorescence under the excitation at 980 nm in a power density only about 50 mW·cm-2. A broad spectrum with a dominant resonance at g of about 2 is observed by the electron paramagnetic resonance (EPR) spectrum of CSUCNPs. Above properties suggest that the obtained CSUCNPs could be potential candidates for dual-mode optical/magnetic bioapplications.

  19. Measurements of the liquidus surface and solidus transitions of the NaCl-UCl3 and NaCl-UCl3-CeCl3 phase diagrams

    NASA Astrophysics Data System (ADS)

    Sooby, E. S.; Nelson, A. T.; White, J. T.; McIntyre, P. M.

    2015-11-01

    NaCl-UCl3-PuCl3 is proposed as the fuel salt for a number of molten salt reactor concepts. No experimental data exists for the ternary system, and limited data is available for the binary compositions of this salt system. Differential scanning calorimetry is used in this study to examine the liquidus surface and solidus transition of a surrogate fuel-salt (NaCl-UCl3-CeCl3) and to reinvestigate the NaCl-UCl3 eutectic phase diagram. The results of this study show good agreement with previously reported data for the pure salt compounds used (NaCl, UCl3, and CeCl3) as well as for the eutectic points for the NaCl-UCl3 and NaCl-CeCl3 binary systems. The NaCl-UCl3 liquidus surface produced in this study predicts a 30-40 °C increase on the NaCl-rich side of the binary phase diagram. The increase in liquidus temperature could prove significant to molten salt reactor modeling.

  20. Composition and evolution of the solid-electrolyte interphase in Na2Ti3O7 electrodes for Na-ion batteries: XPS and Auger parameter analysis.

    PubMed

    Muñoz-Márquez, Miguel A; Zarrabeitia, Maider; Castillo-Martínez, Elizabeth; Eguía-Barrio, Aitor; Rojo, Teófilo; Casas-Cabanas, Montse

    2015-04-15

    Na2Ti3O7 is considered a promising negative electrode for Na-ion batteries; however, poor capacity retention has been reported and the stability of the solid-electrolyte interphase (SEI) could be one of the main actors of this underperformance. The composition and evolution of the SEI in Na2Ti3O7 electrodes is hereby studied by means of X-ray photoelectron spectroscopy (XPS). To overcome typical XPS limitations in the photoelectron energy assignments, the analysis of the Auger parameter is here proposed for the first time in battery materials characterization. We have found that the electrode/electrolyte interface formed upon discharge, mostly composed by carbonates and semicarbonates (Na2CO3, NaCO3R), fluorides (NaF), chlorides (NaCl) and poly(ethylene oxide)s, is unstable upon electrochemical cycling. Additionally, solid state nuclear magnetic resonance (NMR) studies prove the reaction of the polyvinylidene difluoride (PVdF) binder with sodium. The powerful approach used in this work, namely Auger parameter study, enables us to correctly determine the composition of the electrode surface layer without any interference from surface charging or absolute binding energy calibration effects. As a result, the suitability for Na-ion batteries of binders and electrolytes widely used for Li-ion batteries is questioned here. PMID:25811538

  1. On the entangled growth of NaTaO3 cubes and Na2Ti3O7 wires in sodium hydroxide solution.

    PubMed

    Baumann, Stefan O; Liu, Chang; Elser, Michael J; Sternig, Andreas; Siedl, Nicolas; Berger, Thomas; Diwald, Oliver

    2013-07-29

    The entangled growth of sodium titanate Na2Ti3O7 nanowires and sodium tantalate NaTaO3 cubes was investigated with electron microscopy, X-ray diffraction, and UV diffuse reflectance spectroscopy. Depending on the composition of the Ta2O5- and TiO2-particle-based powder mixtures, which served as educts, we observed different types of hybridization effects. These include the titanium-induced contraction of the NaTaO3 perovskite-type unit cell and the generation of electronic defect states in NaTaO3 that give rise to optical subbandgap transitions and tantalum-induced limitations of the Na2Ti3O7 nanowire growth. The transformation from Ta2O5 to NaTaO3 occurs through a dissolution-recrystallization process. A systematic analysis of the impact of different titanium sources on NaTaO3 dispersion and, thus, on the properties of the entangled nanostructures revealed that a perfect intermixture of cubes and nanowires can only be achieved when titanate nanosheets emerge during transformation as reaction intermediates and shield nucleation and growth of isolated NaTaO3 cubes. The here demonstrated approach can be highly instrumental for understanding the nucleation and growth of composite and entangled nanostructures in solution and--at the same time--provides an interesting new class of photoactive composite materials.

  2. A double-tuned (1)H/(23)Na dual resonator system for tissue sodium concentration measurements in the rat brain via Na-MRI.

    PubMed

    Wetterling, Friedrich; Tabbert, Martin; Junge, Sven; Gallagher, Lindsay; Macrae, I Mhairi; Fagan, Andrew J

    2010-12-21

    A method for quantifying the tissue sodium concentration (TSC) in the rat brain from ²³Na-MR images was developed. TSC is known to change in a variety of common human diseases and holds considerable potential to contribute to their study; however, its accurate measurement in small laboratory animals has been hindered by the extremely low signal to noise ratio (SNR) in ²³Na images. To address this, the design, construction and characterization of a double-tuned ¹H/²³Na dual resonator system for ¹H-guided quantitative ²³Na-MRI are described. This system comprises an SNR-optimized surface detector coil for ²³Na image acquisition, and a volume resonator producing a highly homogeneous B₁ field (<5% inhomogeneity) for the Na channel across the rat head. The resonators incorporated channel-independent balanced matching and tuning capabilities with active decoupling circuitry at the ²³Na resonance frequency. A quantification accuracy of TSC of <10 mM was achieved in Na-images with 1.2 µl voxel resolution acquired in 10 min. The potential of the quantification technique was demonstrated in an in vivo experiment of a rat model of cerebral stroke, where the evolution of the TSC was successfully monitored for 8 h after the stroke was induced. PMID:21113090

  3. Probabilistic models to describe the effect of NaNO2 in combination with NaCl on the growth inhibition of Lactobacillus in frankfurters.

    PubMed

    Lee, Soomin; Lee, Heeyoung; Kim, Sejeong; Lee, Jeeyeon; Ha, Jimyeong; Gwak, Eunji; Oh, Mi-Hwa; Park, Beom-Young; Kim, Jin-Seok; Choi, Kyoung-Hee; Yoon, Yohan

    2015-12-01

    Probabilistic models were developed to describe the antimicrobial effect of NaNO2 (0-210 ppm) in combination with NaCl (0-1.75%) on Lactobacillus growth under aerobic and anaerobic conditions. Growth (1) or no growth (0) was assessed every 24h as turbid or not turbid, respectively. The growth response data were analyzed by logistic regression to select significant variables (P<0.05) for Lactobacillus growth inhibition, and these variables were used to generate a probabilistic model. The model was then validated with observed data from frankfurters (a model system). NaNO2 and NaCl inhibited (P<0.05) Lactobacillus growth at all temperatures under aerobic and anaerobic conditions, and the antimicrobial effect of NaNO2 increased as the NaCl concentration increased. Validation showed that the performance of the developed model was appropriate. These results indicate that the models developed in this study should be useful for describing the antimicrobial effect of NaNO2 in combination with NaCl on Lactobacillus.

  4. Relation of Na+, K(+)-ATPase to delayed motor nerve conduction velocity: effect of aldose reductase inhibitor, ADN-138, on Na+, K(+)-ATPase activity.

    PubMed

    Hirata, Y; Okada, K

    1990-06-01

    The role of sorbitol, myo-inositol, and Na+, K(+)-adenosine triphosphatase (ATPase) activity on motor nerve conduction velocity (MNCV) in streptozotocin (STZ)-diabetic rats was studied. Reduction of MNCV and Na+, K(+)-ATPase in caudal nerves appeared after 3 weeks of diabetes, and at this time treatment with aldose reductase inhibitor (ARI), ADN-138 and 1% myo-inositol supplement was begun. One percent myo-inositol supplement for 3 weeks resulted in a significant increase in myo-inositol levels in diabetic nerves, but left MNCV and sorbitol levels unchanged. In contrast, treatment with ADN-138 for 3 weeks reduced sorbitol levels in diabetic nerves and resulted in significant increases in MNCV and Na+, K(+)-ATPase in the nerves. Since ADN-138 did not restore myo-inositol levels, the increase in Na+, K(+)-ATPase levels by ADN-138 treatment was independent of myo-inositol levels. Also, nerve Na+ levels in ADN-138-treated rats were reduced and the ratio of K+ to Na+ was raised, while 1% myo-inositol supplement did not affect them. These results suggest that treatment with ADN-138 elevates MNCV through a series of processes: ARI----reduction of sorbitol level----increase in Na+, K(+)-ATPase activity----correction of K+, Na+ imbalance----increase in MNCV.

  5. The effect of antidiuretic hormone on Na movement across frog skin

    PubMed Central

    Cereijido, M.; Rotunno, Catalina A.

    1971-01-01

    1. The effect of antidiuretic hormone (ADH) on the movement and distribution of Na was studied. This was done using three different approaches: (a) the measurement of Na and 22Na in slices of epithelium of skins which were exposed to Ringer of varied composition containing 22Na, (b) the measurement of the influx of Na from the outer to the inner bathing solution with 22Na added to the outside, and (c) the use of a recently introduced technique which permits the direct evaluation of the flux from the outer solution → epithelium, (JOT), i.e. the flux across the barrier which is generally regarded as the site of ADH activity. 2. ADH increased the influx from the outer to the inner bathing solution of Na (50%) not only when the concentration of Na on the outside was 115 mM (i.e. higher than in the epithelium) but even when the concentration was 1 mM (67%). 3. When the skin was bathed with 1mM-Na Ringer on the outside, ADH increased the unidirectional Na flux JOT by 56% (Rana pipiens) and 71% (Leptodactylus ocellatus). When the concentration was 115 mM a small increase (17%) was observed in paired skins of R. pipiens. Under this condition no change was observed in L. ocellatus. 4. The amount of epithelial sodium which is labelled by 22Na added to the outside was taken to reflect the amount of Na involved in Na transport across the epithelium. Depending on whether the concentration of Na on the outside was high (115 mM) or low (1 mM), ADH produced an increase, or a decrease, of both the total Na content and the amount of 22Na exchanged. 5. When the concentration of Na on the outside was low, ADH increased the total influx and JOT in spite of the fact that it lowers the total Na content and does not affect the exchangeable pool of Na. This observation is inconsistent with the view that the effect of ADH is due to the fact that the increased permeability of the outer barrier allows more Na into the cell, and that the resulting increase of Na concentration in the

  6. Enhanced Infrared Surveillance Imaging Report for NA-22

    SciTech Connect

    Carrano, C J

    2005-10-04

    The purpose of this report is to describe our work on enhanced infrared (IR) surveillance using speckle imaging for NA-22. Speckle imaging in this context is an image post-processing algorithm that aims to solve the atmospheric blurring problem of imaging through horizontal or slant path turbulence. We will describe the IR imaging systems used in our data collections and show imagery before and after speckle processing. We will also compare IR imagery with visible wavelength imagery of the same target in the same conditions and demonstrate how going to longer wavelengths can be beneficial in the presence of strong turbulence.

  7. Digital pulse processing for NaI(Tl) detectors

    NASA Astrophysics Data System (ADS)

    Di Fulvio, A.; Shin, T. H.; Hamel, M. C.; Pozzi, S. A.

    2016-01-01

    We apply two different post-processing techniques to digital pulses induced by photons in a NaI(Tl) detector and compare the obtained energy resolution to the standard analog approach. Our digital acquisition approach is performed using a single-stage acquisition with a fast digitizer. Both the post-processing techniques we propose rely on signal integration. In the first, the pulse integral is calculated by directly numerically integrating the pulse digital samples, while in the second the pulse integral is estimated by a model-based fitting of the pulse. Our study used a 7.62 cm×7.62 cm cylindrical NaI(Tl) detector that gave a 7.60% energy resolution (at 662 keV), using the standard analog acquisition approach, based on a pulse shaping amplifier. The new direct numerical integration yielded a 6.52% energy resolution. The fitting approach yielded a 6.55% energy resolution, and, although computationally heavier than numerical integration, is preferable when only the early samples of the pulse are available. We also evaluated the timing performance of a fast-slow detection system, encompassing an EJ-309 and a NaI(Tl) scintillator. We use two techniques to determine the pulse start time: constant fraction discrimination (CFD) and adaptive noise threshold timing (ANT), for both the analog and digital acquisition approach. With the analog acquisition approach, we found a system time resolution of 5.8 ns and 7.3 ns, using the constant fraction discrimination and adaptive noise threshold timing, respectively. With the digital acquisition approach, a time resolution of 1.2 ns was achieved using the ANT method and 3.3 ns using CFD at 50% of the maximum, to select the pulse start time. The proposed direct digital readout and post-processing techniques can improve the application of NaI(Tl) detectors, traditionally considered 'slow', for fast counting and correlation measurements, while maintaining a good measurement of the energy resolution.

  8. Sensitivity analysis of Na narrowband wind-temperature lidar systems.

    PubMed

    Papen, G C; Pfenninger, W M; Simonich, D M

    1995-01-20

    The performance and measurement accuracy of Na narrowband wind-temperature lidar systems are characterized. Error budgets are derived that include several effects not previously reported, such as power-dependent spectral characteristics in the frequency reference, magnetic-field-dependent oscillator line strengths (Hanle effect), saturation, and optical pumping. It is shown that the overall system uncertainty is dependent on the power, pulse temporal characteristics, and beam divergence of the laser transmitter. Results indicate that even systems with significant saturation can produce accurate measurements, which implies the prospect of continuous daytime wind and temperature measurements on semidiurnal and diurnal time periods.

  9. The Level 0 Trigger Processor for the NA62 experiment

    NASA Astrophysics Data System (ADS)

    Chiozzi, S.; Gamberini, E.; Gianoli, A.; Mila, G.; Neri, I.; Petrucci, F.; Soldi, D.

    2016-07-01

    In the NA62 experiment at CERN, the intense flux of particles requires a high-performance trigger for the data acquisition system. A Level 0 Trigger Processor (L0TP) was realized, performing the event selection based on trigger primitives coming from sub-detectors and reducing the trigger rate from 10 to 1 MHz. The L0TP is based on a commercial FPGA device and has been implemented in two different solutions. The performance of the two systems are highlighted and compared.

  10. Analysis of Cl and Na in Hyperimmune Sera by NAA

    NASA Astrophysics Data System (ADS)

    Baptista, T. S.; Zamboni, C. B.; Marcelino, J. R.

    2011-08-01

    The Cl and Na concentration values in four types of hyperimmune sera (anti-Bothrops, anti-Diphtheria, anti-Rabies and anti-Tetanus) used for immunological therapy were determined using Neutron Activation Analysis (NAA). These data were compatible with the specifications established by the Word Health Organization (WHO-OMS) and with the Brazilian Official Pharmacopea (Pharmaceutical Code Official of the Country). These data are an important support for quality control of hyperimmune sera production at Butantan Institute (São Paulo city, Brazil), responsible for supplying the Brazilian market.

  11. Study of Neutron-Unbound States with MoNA

    NASA Astrophysics Data System (ADS)

    Kuchera, A. N.; Spyrou, A.; Smith, J. K.; Baumann, T.; Christian, G.; De Young, P. A.; Finck, J. E.; Frank, N.; Jones, M. D.; Kohley, Z.; Mosby, S.; Peters, W. A.; Thoennessen, M.

    2015-06-01

    The Modular Neutron Array (MoNA) in conjunction with the large-gap Sweeper magnet at the NSCL is an effective setup to explore neutron-unbound states and has been operating for ten years. Neutron-unbound nuclei beyond the drip-line as well as neutron unbound excited states of bound nuclei have been populated primarily using proton removal reactions. A recent example, the search for 3n emission of the decay of 15Be to1 12Be, is discussed.

  12. The toxicity of NaF on BmN cells and a comparative proteomics approach to identify protein expression changes in cells under NaF-stress: impact of NaF on BmN cells.

    PubMed

    Chen, Liang; Chen, Huiqing; Yao, Chun; Chang, Cheng; Xia, Hengchuan; Zhang, Chunxia; Zhou, Yang; Yao, Qin; Chen, Keping

    2015-04-01

    Fluorides negatively affect the development of organisms and are a threat to human health and environmental safety. In this study, Bombyx mori N cell line (BmN) were used to explore effects of NaF on insect cells. We found that 8h (hrs) culture with high concentration of NaF (≥ 1 mM) induced significantly morphological changes. Dose-response curves of 72 h continuously cultured BmN treated with NaF showed that the half inhibitory concentration (IC50) value was 56.60 μM. Treatment of BmN with 100 and 300 μM of NaF induced apoptosis and necrosis. 2-D electrophoresis of whole cell extracted from BmN showed that treatment with 300 μM NaF up-regulated 32 proteins and down-regulated 11 proteins when compared with controls. We identified 5 different proteins by MALDI-TOF MS, and 4 of them were identified for the first time, including 2 up-regulated proteins (mitochondrial aldehyde dehydrogenase ALDH2 and prohibitin protein WPH) and 2 down-regulated proteins (calreticulin precursor CRT and DNA supercoiling factor SCF). These observations were further confirmed by fluorescence quantitative PCR. Together, our data suggest that these target proteins could be regarded as targets influenced by NaF and also provide clues for studies on the response metabolism pathway under NaF stress.

  13. Energetic aqueous rechargeable sodium-ion battery based on Na2 CuFe(CN)6 -NaTi2 (PO4 )3 intercalation chemistry.

    PubMed

    Wu, Xian-Yong; Sun, Meng-Ying; Shen, Yi-Fei; Qian, Jiang-Feng; Cao, Yu-Liang; Ai, Xin-Ping; Yang, Han-Xi

    2014-02-01

    Aqueous rechargeable sodium-ion batteries have the potential to meet growing demand for grid-scale electric energy storage because of the widespread availability and low cost of sodium resources. In this study, we synthesized a Na-rich copper hexacyanoferrate(II) Na2 CuFe(CN)6 as a high potential cathode and used NaTi2 (PO4 )3 as a Na-deficient anode to assemble an aqueous sodium ion battery. This battery works very well with a high average discharge voltage of 1.4 V, a specific energy of 48 Wh kg(-1) , and an excellent high-rate cycle stability with approximately 90 % capacity retention over 1000 cycles, achieving a new record in the electrochemical performance of aqueous Na-ion batteries. Moreover, all the anode, cathode, and electrolyte materials are low cost and naturally abundant and are affordable for widespread applications. PMID:24464957

  14. Uptake and Loss of Na+, Rb+, and Cs+ in Relation to an Active Mechanism for Extrusion of Na+ in Scenedesmus 1

    PubMed Central

    Kylin, Anders

    1966-01-01

    The mechanism for extrusion of Na+ from Scenedesmus cells is characterized physiologically. It is stimulated by phosphate but oxygen is not necessary. Rb+ and Cs+ may also be extruded, but in the presence of Na+ they cannot compete for the sites on the inside of the transport system. When Na+ is extruded, Rb+ and, by inference, K+ seems to be transported as counter ion from the outside, and sodium ions compete only weakly for this external site. The parallelism between these findings and the Na+-K+-activated adenosine triphosphatases known from animal tissues is pointed out. With low additions of phosphate, the extrusion mechanism can keep the cells practically free from Na+. Increasing the concentrations of external phosphate stimulates uptake more than extrusion, and a net uptake occurs. As for Rb+ and Cs+, they are taken up in the absence of external phosphate, but additions of P will greatly enhance the amounts absorbed. Two different ways of uptake are indicated. PMID:5932402

  15. Results from Boiling Temperature Measurements for Saturated Solutions in the Systems NaCl + Ca(NO3)2 + H2O, NaNO3 + KNO3 + H2O, and NaCl + KNO3 + H2O, and Dry Out Temperatures for NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O

    SciTech Connect

    Rard, J A

    2005-11-29

    Boiling temperature measurements have been made for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O and NaNO{sub 3} + KNO{sub 3} + H{sub 2}O at three selected salt ratios and for NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O over the full composition range. The maximum boiling temperature found for the NaCl + Ca(NO{sub 3}){sub 2} + H{sub 2}O system is 164.7 {+-} 0.6 C, and the composition is estimated to occur at x(Ca(NO{sub 3}){sub 2}) {approx} 0.25. Experiments were also performed for the five component NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O mixtures with the molar ratio of NaCl:NaNO{sub 3}:KNO{sub 3} held essentially constant at 1:0.9780:1.1468 as the solute mole fraction of Ca(NO{sub 3}){sub 2}, x(Ca(NO{sub 3}){sub 2}), was varied between 0 and 0.25. The NaCl + NaNO{sub 3} + KNO{sub 3} + Ca(NO{sub 3}){sub 2} + H{sub 2}O system forms low melting mixtures and thus boiling temperatures for saturated were not determined. Instead, the temperatures corresponding to the cessation of boiling (i.e., dry out temperatures) of these liquid mixtures were determined. These dry out temperatures range from {approx} 300 C when x(Ca(NO{sub 3}){sub 2}) = 0 to {ge} 400 C when x(Ca(NO{sub 3}){sub 2}) = 0.20 and 0.25. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control the deliquescence relative humidity of salts formed by leaching dust samples from the proposed nuclear repository at Yucca Mountain, Nevada.

  16. Growth mechanism and magnetic and electrochemical properties of Na{sub 0.44}MnO{sub 2} nanorods as cathode material for Na-ion batteries

    SciTech Connect

    Demirel, S.; Oz, E.; Altin, E.; Altin, S.; Bayri, A.; Kaya, P.; Turan, S.; Avci, S.

    2015-07-15

    Nanorods of Na{sub 0.44}MnO{sub 2} are a promising cathode material for Na-ion batteries due to their large surface area and single crystalline structure. We report the growth mechanism of Na{sub 0.44}MnO{sub 2} nanorods via solid state synthesis and their physical properties. The structure and the morphology of the Na{sub 0.44}MnO{sub 2} nanorods are investigated by X-ray diffraction (XRD), scanning and tunneling electron microscopy (SEM and TEM), and energy-dispersive X-ray (EDX) techniques. The growth mechanism of the rods is investigated and the effects of vapor pressure and partial melting of Na-rich regions are discussed. The magnetic measurements show an antiferromagnetic phase transition at 25 K and the μ{sub eff} is determined as 3.41 and 3.24 μ{sub B} from the χ–T curve and theoretical calculation, respectively. The electronic configuration and spin state of Mn{sup 3+} and Mn{sup 4+} are discussed in detail. The electrochemical properties of the cell fabricated using the nanorods are investigated and the peaks in the voltammogram are attributed to the diffusion of Na ions from different sites. Na intercalation process is explained by one and two Margules and van Laar models. - Highlights: • We synthesized Na{sub 0.44}MnO{sub 2} nanorods via a simple solid state reaction technique. • Our studies show that excess Na plays a crucial role in the nanorod formation. • Magnetization measurements show that Mn{sup 3+} ions are in LS and HS states. • The electrochemical properties of the cell fabricated using the nanorods are investigated. • Na intercalation process is explained by one and two Margules and van Laar models.

  17. Ranolazine vs phenytoin: greater effect of ranolazine on the transient Na(+) current than on the persistent Na(+) current in central neurons.

    PubMed

    Terragni, Benedetta; Scalmani, Paolo; Colombo, Elisa; Franceschetti, Silvana; Mantegazza, Massimo

    2016-11-01

    Voltage-gated Na(+) channels (NaV) are involved in pathologies and are important targets of drugs (NaV-blockers), e.g. some anti-epileptic drugs (AEDs). Besides the fast inactivating transient Na(+) current (INaT), they generate a slowly inactivating "persistent" current (INaP). Ranolazine, a NaV-blocker approved for treatment of angina pectoris, is considered a preferential inhibitor of INaP and has been proposed as a novel AED. Although it is thought that classic NaV-blockers used as AEDs target mainly INaT, they can also reduce INaP. It is important to disclose specific features of novel NaV-blockers, which could be necessary for their effect as AEDs in drug resistant patients. We have compared the action of ranolazine and of the classic AED phenytoin in transfected cells expressing the neuronal NaV1.1 Na(+) channel and in neurons of neocortical slices. Our results show that the relative block of INaT versus INaP of ranolazine and phenytoin is variable and depends on Na(+) current activation conditions. Strikingly, ranolazine blocks with less efficacy INaP and more efficacy INaT than phenytoin in conditions mimicking pathological states (i.e. high frequency firing and long lasting depolarizations). The effects are consistent with binding of ranolazine to both open/pre-open and inactivated states; larger INaT block at high stimulation frequencies is caused by the induction of a slow inactivated state. Thus, contrary than expected, ranolazine is not a better INaP blocker than phenytoin in central neurons, and phenytoin is not a better INaT blocker than ranolazine. Nevertheless, they show a complementary action and could differentially target specific pathological dysfunctions.

  18. NaF-mediated controlled-synthesis of multicolor Na(x)ScF(3+x):Yb/Er upconversion nanocrystals.

    PubMed

    Pei, Wen-Bo; Chen, Bo; Wang, Lili; Wu, Jiansheng; Teng, Xue; Lau, Raymond; Huang, Ling; Huang, Wei

    2015-03-01

    Synthesis of lanthanide-doped upconversion nanocrystals (LDUNs) with controlled morphology and luminescence has long been desired in order to fulfill various application requirements. In this work, we have investigated the effect of the NaF : Ln(3+) molar ratio, in the range of 1 to 20, on the morphology, crystal structure, and upconversion properties of NaxScF(3+x):Yb/Er nanocrystals that are reported to possess different upconversion properties from those of NaYF4:Yb/Er nanocrystals. The experimental results prove that the NaF : Ln(3+) molar ratio influences significantly the growth process of the nanocrystals, i.e. a low NaF : Ln(3+) molar ratio results in hexagonal NaScF4 nanocrystals, while a high NaF : Ln(3+) molar ratio favors monoclinic Na3ScF6 nanocrystals. When the NaF : Ln(3+) molar ratio is as high as 6 or above, phase separation is found and hexagonal NaYbF4 nanocrystals showed up for the first time. Simply by adjusting the NaF : Ln(3+) molar ratio, we have successfully achieved the simultaneous control of the shape, size, as well as the crystallographic phase of the NaxScF(3+x):Yb/Er nanocrystals, which give different red to green (R/G) ratios (integral area), leading to a multicolor upconversion luminescence from orange-red to green. This study provides a vivid example to track and interpret the formation mechanisms and growth processes of NaxScF(3+x):Yb/Er nanocrystals, which shall be instructive for guiding the controlled synthesis of other LDUNs and extending their according applications in optical communication, color display, anti-counterfeiting, bioimaging, and so on.

  19. Crystal Structure of High-Temperature Phase β-NaSrBO3 and Photoluminescence of β-NaSrBO3:Ce(3.).

    PubMed

    Yi, Huan; Wu, Li; Wu, Liwei; Zhao, Lixia; Xia, Zhiguo; Zhang, Yi; Kong, Yongfa; Xu, Jingjun

    2016-07-01

    α-NaSrBO3 is an excellent phosphor host for phosphor-converted white light-emitting diode (w-LED) application with very interesting properties. However, it undergoes a phase transformation to β-NaSrBO3 at the LED working temperature. In this study, the high-temperature phase β-NaSrBO3 was stabilized to room temperature by introducing Na(+) and Ce(3+) via a high-temperature solid-state reaction method. The crystal structure of β-NaSrBO3 was determined from the powder X-ray diffraction data. It crystallizes in space group P21/c with the following lattice parameters: a = 6.06214(8) Å, b = 5.41005(7) Å, c = 9.1468(1) Å, β = 102.116(1)°, and V = 293.301(7) Å(3). Na and Sr sites are found to be mixed occupied by each other, and the isolated [BO3](3-) anionic groups are distributed in parallel. Ce(3+)-activated β-NaSrBO3:Ce(3+) blue-emitting phosphors were synthesized. The temperature-dependent photoluminescence spectra indicate that the thermal stability of β-NaSrBO3:Ce(3+) is better than that of α-NaSrBO3:Ce(3+) at the same temperature. A near-ultraviolet pumped warm w-LED with a β-NaSrBO3:0.05Ce(3+) phosphor as the blue component was fabricated. The w-LED lamp after illumination at 250 mA gives chromaticity coordinates, a color rendering index, and a correlated color temperature of (0.3821, 0.3430), 92.8, and 3654 K, respectively. PMID:27299933

  20. Ranolazine vs phenytoin: greater effect of ranolazine on the transient Na(+) current than on the persistent Na(+) current in central neurons.

    PubMed

    Terragni, Benedetta; Scalmani, Paolo; Colombo, Elisa; Franceschetti, Silvana; Mantegazza, Massimo

    2016-11-01

    Voltage-gated Na(+) channels (NaV) are involved in pathologies and are important targets of drugs (NaV-blockers), e.g. some anti-epileptic drugs (AEDs). Besides the fast inactivating transient Na(+) current (INaT), they generate a slowly inactivating "persistent" current (INaP). Ranolazine, a NaV-blocker approved for treatment of angina pectoris, is considered a preferential inhibitor of INaP and has been proposed as a novel AED. Although it is thought that classic NaV-blockers used as AEDs target mainly INaT, they can also reduce INaP. It is important to disclose specific features of novel NaV-blockers, which could be necessary for their effect as AEDs in drug resistant patients. We have compared the action of ranolazine and of the classic AED phenytoin in transfected cells expressing the neuronal NaV1.1 Na(+) channel and in neurons of neocortical slices. Our results show that the relative block of INaT versus INaP of ranolazine and phenytoin is variable and depends on Na(+) current activation conditions. Strikingly, ranolazine blocks with less efficacy INaP and more efficacy INaT than phenytoin in conditions mimicking pathological states (i.e. high frequency firing and long lasting depolarizations). The effects are consistent with binding of ranolazine to both open/pre-open and inactivated states; larger INaT block at high stimulation frequencies is caused by the induction of a slow inactivated state. Thus, contrary than expected, ranolazine is not a better INaP blocker than phenytoin in central neurons, and phenytoin is not a better INaT blocker than ranolazine. Nevertheless, they show a complementary action and could differentially target specific pathological dysfunctions. PMID:27450092

  1. Co-intercalation of Mg(2+) and Na(+) in Na(0.69)Fe2(CN)6 as a High-Voltage Cathode for Magnesium Batteries.

    PubMed

    Kim, Dong-Min; Kim, Youngjin; Arumugam, Durairaj; Woo, Sang Won; Jo, Yong Nam; Park, Min-Sik; Kim, Young-Jun; Choi, Nam-Soon; Lee, Kyu Tae

    2016-04-01

    Thanks to the advantages of low cost and good safety, magnesium metal batteries get the limelight as substituent for lithium ion batteries. However, the energy density of state-of-the-art magnesium batteries is not high enough because of their low operating potential; thus, it is necessary to improve the energy density by developing new high-voltage cathode materials. In this study, nanosized Berlin green Fe2(CN)6 and Prussian blue Na(0.69)Fe2(CN)6 are compared as high-voltage cathode materials for magnesium batteries. Interestingly, while Mg(2+) ions cannot be intercalated in Fe2(CN)6, Na(0.69)Fe2(CN)6 shows reversible intercalation and deintercalation of Mg(2+) ions, although they have the same crystal structure except for the presence of Na(+) ions. This phenomenon is attributed to the fact that Mg(2+) ions are more stable in Na(+)-containing Na(0.69)Fe2(CN)6 than in Na(+)-free Fe2(CN)6, indicating Na(+) ions in Na(0.69)Fe2(CN)6 plays a crucial role in stabilizing Mg(2+) ions. Na(0.69)Fe2(CN)6 delivers reversible capacity of approximately 70 mA h g(-1) at 3.0 V vs Mg/Mg(2+) and shows stable cycle performance over 35 cycles. Therefore, Prussian blue analogues are promising structures for high-voltage cathode materials in Mg batteries. Furthermore, this co-intercalation effect suggests new avenues for the development of cathode materials in hybrid magnesium batteries that use both Mg(2+) and Na(+) ions as charge carriers.

  2. A new diabatic representation of the coupled potential energy surfaces for Na(3p P-2) + H2 yields Na(3s S-2) + H2 or NaH + H

    NASA Technical Reports Server (NTRS)

    Halvick, Philippe; Truhlar, Donald G.

    1992-01-01

    A diabatic representation is presented of the coupled potential-energy surfaces for Na(3p P-2) + H2 yields Na (3s S-2) + H2 or NaH + H. The representation is designed to yield, upon diagonalization, realistic values for the two lowest energy adiabatic states at both asymptotes of the chemical reaction as well as near the conical intersection in the three-body interaction region. It is economical to evaluate and portable. It is suitable for dynamics calculations on both the quenching process and the electronically nonadiabatic chemical reaction.

  3. Functional tetrodotoxin-resistant Na(+) channels are expressed presynaptically in rat dorsal root ganglia neurons.

    PubMed

    Medvedeva, Y V; Kim, M-S; Schnizler, K; Usachev, Y M

    2009-03-17

    The tetrodotoxin-resistant (TTX-R) voltage-gated Na(+) channels Na(v)1.8 and Na(v)1.9 are expressed by a subset of primary sensory neurons and have been implicated in various pain states. Although recent studies suggest involvement of TTX-R Na(+) channels in sensory synaptic transmission and spinal pain processing, it remains unknown whether TTX-R Na(+) channels are expressed and function presynaptically. We examined expression of TTX-R channels at sensory synapses formed between rat dorsal root ganglion (DRG) and spinal cord (SC) neurons in a DRG/SC co-culture system. Immunostaining showed extensive labeling of presynaptic axonal boutons with Na(v)1.8- and Na(v)1.9-specific antibodies. Measurements using the fluorescent Na(+) indicator SBFI demonstrated action potential-induced presynaptic Na(+) entry that was resistant to tetrodotoxin (TTX) but was blocked by lidocaine. Furthermore, presynaptic [Ca(2+)](i) elevation in response to a single action potential was not affected by TTX in TTX-resistant DRG neurons. Finally, glutamatergic synaptic transmission was not inhibited by TTX in more than 50% of synaptic pairs examined; subsequent treatment with lidocaine completely blocked these TTX-resistant excitatory postsynaptic currents. Taken together, these results provide evidence for presynaptic expression of functional TTX-R Na(+) channels that may be important for shaping presynaptic action potentials and regulating transmitter release at the first sensory synapse. PMID:19162133

  4. Alpha adrenergic modulation of the Na/sup +/ pump of canine vascular smooth muscle

    SciTech Connect

    Navran, S.S.; Adair, S.E.; Allen, J.C.; Seidel, C.L.

    1986-03-01

    Some vasoactive agents, eg. beta adrenergic agonists and forskolin, stimulate the Na/sup 7/ pump by a cAMP- dependent mechanism. The authors have now demonstrated that phenylephrine (PE) stimulates the Na/sup 7/ pump in intact blood vessels as quantitated by an increased ouabain-sensitive /sup 86/Rb uptake. The stimulation is dose-dependent (ED/sub 50/, 3 x 10/sup -6/M) and blocked by phentolamine (I/sub 50/, 10/sup -7/M), prazosin (I/sub 50/, 10/sup -8/M) yohimbine (I/sub 50/, 10/sup -6/M) or elevated intracellular Na/sup +/. These data suggest that the Na/sup +/ pump stimulation is mediated through alpha/sub 1/ receptors which produce an influx of extracellular Na/sup +/. In vascular smooth muscle cell cultures PE stimulates the Na/sup +/ pump, but only when cells have been deprived of fetal calf serum (FCS). Since FCS is known to stimulate Na/sup +/influx, in the continuous presence of FCS, these cells may already be Na/sup +/-loaded and therefore refractory to further stimulation by alpha-adrenergic agents. Unlike those vasorelaxants whose mechanism involves stimulation of the Na/sup +/ pump, alpha adrenergic agents are vasoconstrictors and therefore the role of Na/sup +/ pump stimulation in this case may be as a mechanism of feedback inhibition of contractility.

  5. Regulation of Cardiac Remodeling by Cardiac Na+/K+-ATPase Isoforms

    PubMed Central

    Liu, Lijun; Wu, Jian; Kennedy, David J.

    2016-01-01

    Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na+/K+-ATPase has multiple α isoforms (1–3). The expression of the α subunit of the Na+/K+-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na+/K+-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na+/K+-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na+/K+-ATPase regulates intracellular Ca2+ signaling, contractility and pathological hypertrophy. The α3 isoform of the Na+/K+-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na+/K+-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na+/K+-ATPase in the cardiomyocytes. (2) the role of cardiac Na+/K+-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na+/K+-ATPase isoform may offer a new target for the prevention of cardiac remodeling. PMID:27667975

  6. Regulation of Cardiac Remodeling by Cardiac Na+/K+-ATPase Isoforms

    PubMed Central

    Liu, Lijun; Wu, Jian; Kennedy, David J.

    2016-01-01

    Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na+/K+-ATPase has multiple α isoforms (1–3). The expression of the α subunit of the Na+/K+-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na+/K+-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na+/K+-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na+/K+-ATPase regulates intracellular Ca2+ signaling, contractility and pathological hypertrophy. The α3 isoform of the Na+/K+-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na+/K+-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na+/K+-ATPase in the cardiomyocytes. (2) the role of cardiac Na+/K+-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na+/K+-ATPase isoform may offer a new target for the prevention of cardiac remodeling.

  7. High sodium ion conductivity of glass-ceramic electrolytes with cubic Na3PS4

    NASA Astrophysics Data System (ADS)

    Hayashi, Akitoshi; Noi, Kousuke; Tanibata, Naoto; Nagao, Motohiro; Tatsumisago, Masahiro

    2014-07-01

    Sulfide solid electrolytes with cubic Na3PS4 phase has relatively high sodium ion conductivity of over 10-4 S cm-1 at room temperature, and all-solid-state sodium batteries Na-Sn/TiS2 with the electrolyte operated as a secondary battery at room temperature. To improve battery performance, conductivity enhancement of sulfide electrolytes is important. In this study, we have succeeded in enhancing conductivity by optimizing preparation conditions of Na3PS4 glass-ceramic electrolytes. By use of crystalline Na2S with high purity of 99.1%, cubic Na3PS4 crystals were directly precipitated by ball milling process at the composition of 75Na2S·25P2S5 (mol%). The glass-ceramic electrolyte prepared by milling for 1.5 h and consecutive heat treatment at 270 °C for 1 h showed the highest conductivity of 4.6 × 10-4 S cm-1, which is twice as high as the conductivity of the cubic Na3PS4 glass-ceramic prepared in a previous report. All-solid-state Na-Sn/NaCrO2 cells with the newly prepared electrolyte exhibited charge-discharge cycles at room temperature and kept about 60 mAh per gram of NaCrO2 for 15 cycles.

  8. Regulation of Cardiac Remodeling by Cardiac Na(+)/K(+)-ATPase Isoforms.

    PubMed

    Liu, Lijun; Wu, Jian; Kennedy, David J

    2016-01-01

    Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na(+)/K(+)-ATPase has multiple α isoforms (1-3). The expression of the α subunit of the Na(+)/K(+)-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na(+)/K(+)-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na(+)/K(+)-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na(+)/K(+)-ATPase regulates intracellular Ca(2+) signaling, contractility and pathological hypertrophy. The α3 isoform of the Na(+)/K(+)-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na(+)/K(+)-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na(+)/K(+)-ATPase in the cardiomyocytes. (2) the role of cardiac Na(+)/K(+)-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na(+)/K(+)-ATPase isoform may offer a new target for the prevention of cardiac remodeling. PMID:27667975

  9. Crystal and electronic structures of nitridophosphate compounds as cathode materials for Na-ion batteries

    NASA Astrophysics Data System (ADS)

    Debbichi, M.; Lebègue, S.

    2015-08-01

    Using density-functional theory, we have studied the electronic and magnetic properties of two promising compounds that can be used as cathode materials, namely, Na2Fe2P3O9N and Na3TiP3O9N . When Na is extracted, we found the volume change to be quite small, with values of ˜-0.6 % for Na3TiP3O9N and -5 % for Na2Fe2P3O9N . Our calculated voltages with the Hubbard-type correction (GGA+U) approximation are 2.93 V for Na3TiP3O9N /Na2TiP3O9N and 2.68 V for Na2Fe2P3O9N /NaFe2P3O9N , in good agreement with the experimental data. Our results confirm that these compounds are very promising for rechargeable Na-ion batteries.

  10. Regulation of Cardiac Remodeling by Cardiac Na(+)/K(+)-ATPase Isoforms.

    PubMed

    Liu, Lijun; Wu, Jian; Kennedy, David J

    2016-01-01

    Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na(+)/K(+)-ATPase has multiple α isoforms (1-3). The expression of the α subunit of the Na(+)/K(+)-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na(+)/K(+)-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na(+)/K(+)-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na(+)/K(+)-ATPase regulates intracellular Ca(2+) signaling, contractility and pathological hypertrophy. The α3 isoform of the Na(+)/K(+)-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na(+)/K(+)-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na(+)/K(+)-ATPase in the cardiomyocytes. (2) the role of cardiac Na(+)/K(+)-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na(+)/K(+)-ATPase isoform may offer a new target for the prevention of cardiac remodeling.

  11. Non-reciprocal interactions between K+ and Na+ ions in barley (Hordeum vulgare L.)

    PubMed Central

    Kronzucker, Herbert J.; Szczerba, Mark W.; Schulze, Lasse M.; Britto, Dev T.

    2008-01-01

    The interaction of sodium and potassium ions in the context of the primary entry of Na+ into plant cells, and the subsequent development of sodium toxicity, has been the subject of much recent attention. In the present study, the technique of compartmental analysis with the radiotracers 42K+ and 24Na+ was applied in intact seedlings of barley (Hordeum vulgare L.) to test the hypothesis that elevated levels of K+ in the growth medium will reduce both rapid, futile Na+ cycling at the plasma membrane, and Na+ build-up in the cytosol of root cells, under saline conditions (100 mM NaCl). We reject this hypothesis, showing that, over a wide (400-fold) range of K+ supply, K+ neither reduces the primary fluxes of Na+ at the root plasma membrane nor suppresses Na+ accumulation in the cytosol. By contrast, 100 mM NaCl suppressed the cytosolic K+ pool by 47–73%, and also substantially decreased low-affinity K+ transport across the plasma membrane. We confirm that the cytosolic [K+]:[Na+] ratio is a poor predictor of growth performance under saline conditions, while a good correlation is seen between growth and the tissue ratios of the two ions. The data provide insight into the mechanisms that mediate the toxic influx of sodium across the root plasma membrane under salinity stress, demonstrating that, in the glycophyte barley, K+ and Na+ are unlikely to share a common low-affinity pathway for entry into the plant cell. PMID:18562445

  12. Morphological, physiological, and structural responses of two species of artemisia to NaCl stress.

    PubMed

    Guan, Zhi-Yong; Su, Yi-Ji; Teng, Nian-Jun; Chen, Su-Mei; Sun, Hai-Nan; Li, Chu-Ling; Chen, Fa-Di

    2013-01-01

    Effects of salt stress on Artemisia scoparia and A. vulgaris "Variegate" were examined. A. scoparia leaves became withered under NaCl treatment, whereas A. vulgaris "Variegate" leaves were not remarkably affected. Chlorophyll content decreased in both species, with a higher reduction in A. scoparia. Contents of proline, MDA, soluble carbohydrate, and Na(+) increased in both species under salt stress, but A. vulgaris "Variegate" had higher level of proline and soluble carbohydrate and lower level of MDA and Na(+). The ratios of K(+)/Na(+), Ca(2+)/Na(+), and Mg(2+)/Na(+) in A. vulgaris "Variegate" under NaCl stress were higher. Moreover, A. vulgaris "Variegate" had higher transport selectivity of K(+)/Na(+) from root to stem, stem to middle mature leaves, and upper newly developed leaves than A. scoparia under NaCl stress. A. vulgaris "Variegate" chloroplast maintained its morphological integrity under NaCl stress, whereas A. scoparia chloroplast lost integrity. The results indicated that A. scoparia is more sensitive to salt stress than A. vulgaris "Variegate." Salt tolerance is mainly related to the ability of regulating osmotic pressure through the accumulation of soluble carbohydrates and proline, and the gradient distribution of K(+) between roots and leaves was also contributed to osmotic pressure adjustment and improvement of plant salt tolerance. PMID:24235883

  13. Na-doped hydroxyapatite coating on carbon/carbon composites: Preparation, in vitro bioactivity and biocompatibility

    NASA Astrophysics Data System (ADS)

    Li, Hejun; Zhao, Xueni; Cao, Sheng; Li, Kezhi; Chen, Mengdi; Xu, Zhanwei; Lu, Jinhua; Zhang, Leilei

    2012-12-01

    Na-doped hydroxyapatite (Na-HA) coating was directly prepared onto carbon/carbon (C/C) composites using electrochemical deposition (ECD) and the mean thickness of the coating is approximately 10 ± 2 μm. The formed Na-HA crystals which are Ca-deficient, are rod-like with a hexagonal cross section. The Na/P molar ratios of the coating formed on C/C substrate is 0.097. During the deposition, the Na-HA crystals grow in both radial and longitudinal directions, and faster along the longitudinal direction. The pattern formation of crystal growth leads to dense coating which would help to increase the bonding strength of the coating. The average shear bonding strength of Na-HA coating on C/C is 5.55 ± 0.77 MPa. The in vitro bioactivity of the Na-HA coated C/C composites were investigated by soaking the samples in a simulated body fluid (SBF) for 14 days. The results indicate that the Na-HA coated C/C composites can rapidly induce bone-like apatite nucleation and growth on its surface in SBF. The in vitro cellular biocompatibility tests reveal that the Na-HA coating was better to improve the in vitro biocompatibility of C/C composites compared with hydroxyapatite (HA) coating. It was suggested that the Na-HA coating might be an effective method to improve the surface bioactivity and biocompatibility of C/C composites.

  14. Formation of titanate nanostructures under different NaOH concentration and their application in wastewater treatment

    SciTech Connect

    Huang Jiquan; Cao Yongge; Deng Zhonghua; Tong Hao

    2011-03-15

    The effects of the concentration of NaOH on the formation and transformation of various titanate nanostructures were studied. With increasing NaOH concentration, three different formation mechanisms were proposed. Nanotubes can only be obtained under moderate NaOH conditions, and should transform into nanowires with prolonged hydrothermal treatment, and their formation rate is accelerated by increasing NaOH concentration. Low concentration of NaOH results in the direct formation of nanowires, while extra high concentration of NaOH leads to the formation of amorphous nanoparticles. Adsorption and photocatalysis studies show that titanate nanowires and nanotubes might be potential adsorbents for the removal of both heavy metal ions and dyes and photocatalysts for the removal of dyes from wastewater. -- Graphical abstract: The morphologies of the titanates depend deeply on the concentration of NaOH. With increasing NaOH concentration, three different formation mechanisms were proposed. The application of these titanate nanostructures in the wastewater treatment was studied. Display Omitted Research highlights: {yields} Effect of NaOH concentration on the structures of various titanates was reported. {yields} Three different formation mechanisms were presented with increasing NaOH concentration. {yields} Various titanates were used as adsorbents/photocatalysts in wastewater treatment.

  15. A Na(+) Superionic Conductor for Room-Temperature Sodium Batteries.

    PubMed

    Song, Shufeng; Duong, Hai M; Korsunsky, Alexander M; Hu, Ning; Lu, Li

    2016-01-01

    Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10(-3) S cm(-1). We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor.

  16. Successive orbital ordering transitions in NaVO_2

    SciTech Connect

    Klimczuk, Tomasz W; Mcqueen, T; Stephens, P W; Huang, Q; Ronning, Filip; Cava, R

    2008-01-01

    Temperature-dependent dc susceptibility, heat capacity, and x-ray and neutron diffraction measurements on powder samples of the layered triangular-lattice material NaY02 reveal two successive phase transitions. At high temperature the structure is rhomobohedral, with all six inplane V-V distances equivalent. At T = 98K, the system undergoes a second order phase transition to a monoclinic intermediate temperature phase in which the in-plane Y -Y distances separate into four short and two long bonds, corresponding to orbital ordering of one electron per y3+. Below T 93K, there is a first order phase transition to a low temperature monoclinic phase, in which there are four long and two short in-plane Y -Y distances, consistent with orbital ordering of two electrons per y 3+ on a triangular lattice. Long range magnetic ordering of 0.98(2),uB per y 3 + (3d2) sets in at the T 93K structural transition. The low temperature structure ofNa Y02 displays orbital ordering that, although predicted by first principle calculations, has not previously been observed in this class of materials.

  17. Functional Na+ Channels in Cell Adhesion probed by Transistor Recording

    PubMed Central

    Schmidtner, Markus; Fromherz, Peter

    2006-01-01

    Cell membranes in a tissue are in close contact to each other, embedded in the extracellular matrix. Standard electrophysiological methods are not able to characterize ion channels under these conditions. Here we consider the area of cell adhesion on a solid substrate as a model system. We used HEK 293 cells cultured on fibronectin and studied the activation of NaV1.4 sodium channels in the adherent membrane with field-effect transistors in a silicon substrate. Under voltage clamp, we compared the transistor response with the whole-cell current. We observed that the extracellular voltage in the cell-chip contact was proportional to the total membrane current. The relation was calibrated by alternating-current stimulation. We found that Na+ channels are present in the area of cell adhesion on fibronectin with a functionality and a density that is indistinguishable from the free membrane. The experiment provides a basis for studying selective accumulation and depletion of ion channels in cell adhesion and also for a development of cell-based biosensoric devices and neuroelectronic systems. PMID:16227504

  18. Correction of the Caulobacter crescentus NA1000 genome annotation.

    PubMed

    Ely, Bert; Scott, LaTia Etheredge

    2014-01-01

    Bacterial genome annotations are accumulating rapidly in the GenBank database and the use of automated annotation technologies to create these annotations has become the norm. However, these automated methods commonly result in a small, but significant percentage of genome annotation errors. To improve accuracy and reliability, we analyzed the Caulobacter crescentus NA1000 genome utilizing computer programs Artemis and MICheck to manually examine the third codon position GC content, alignment to a third codon position GC frame plot peak, and matches in the GenBank database. We identified 11 new genes, modified the start site of 113 genes, and changed the reading frame of 38 genes that had been incorrectly annotated. Furthermore, our manual method of identifying protein-coding genes allowed us to remove 112 non-coding regions that had been designated as coding regions. The improved NA1000 genome annotation resulted in a reduction in the use of rare codons since noncoding regions with atypical codon usage were removed from the annotation and 49 new coding regions were added to the annotation. Thus, a more accurate codon usage table was generated as well. These results demonstrate that a comparison of the location of peaks third codon position GC content to the location of protein coding regions could be used to verify the annotation of any genome that has a GC content that is greater than 60%.

  19. Paleothermometry of NaCl as evidenced from thermoluminescence data

    NASA Astrophysics Data System (ADS)

    Gartia, R. K.

    2009-09-01

    The firing temperature of ancient ceramic artifacts, i.e. the paleothermometry of these materials has been estimated by various techniques including thermoluminescence (TL) and, more recently, Optically Stimulated Luminescence (OSL) where the OSL response of quartz to firing temperature is used. In this work we report the paleothermometry of sodium chloride (NaCl) by studying the TL response of the material as a function of annealing temperatures in the range of 100-500 °C. Annealing/measurement has been done in a commercial TL/OSL reader (Model No. Risø TL/OSL reader TL-DA-15) in a nitrogen atmosphere. Sodium chloride (NaCl) has been selected as the candidate to test the feasibility of the technique since in this system TL peaks are correlated with the thermal annealing of F-centers unlike the case of quartz where a one to one correlation with all the glow peaks and thermal annealing of defects has not been possible.

  20. A Na+ Superionic Conductor for Room-Temperature Sodium Batteries

    NASA Astrophysics Data System (ADS)

    Song, Shufeng; Duong, Hai M.; Korsunsky, Alexander M.; Hu, Ning; Lu, Li

    2016-08-01

    Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10‑3 S cm‑1. We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor.

  1. A Na+ Superionic Conductor for Room-Temperature Sodium Batteries

    PubMed Central

    Song, Shufeng; Duong, Hai M.; Korsunsky, Alexander M.; Hu, Ning; Lu, Li

    2016-01-01

    Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10−3 S cm−1. We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor. PMID:27572915

  2. A Na(+) Superionic Conductor for Room-Temperature Sodium Batteries.

    PubMed

    Song, Shufeng; Duong, Hai M; Korsunsky, Alexander M; Hu, Ning; Lu, Li

    2016-01-01

    Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10(-3) S cm(-1). We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor. PMID:27572915

  3. MINOS Calibration and NA49 Hadronic Production Studies

    SciTech Connect

    Morse, Robert James

    2003-08-01

    An overview of the current status of the Main Injector Neutrino Oscillation Search (MINOS) is presented. MINOS is a long-baseline experiment with two detectors situated in North America. The near detector is based at the emission point of the NuMI beam at Fermilab, Chicago, the far detector is 735 km downstream in a disused iron mine in Soudan, Minnesota. A third detector, the calibration detector, is used to cross-calibrate these detectors by sampling different particle beams at CERN. A detailed description of the design and construction of the light-injection calibration system is included. Also presented are experimental investigations into proton-carbon collisions at 158 GeV/c carried out with the NA49 experiment at CERN. The NA49 experiment is a Time Projection Chamber (TPC) based experiment situated at CERN's North Area. It is a well established experiment with well known characteristics. The data gained from this investigation are to be used to parameterize various hadronic production processes in accelerator and atmospheric neutrino production. These hadronic production parameters will be used to improve the neutrino generation models used in calculating the neutrino oscillation parameters in MINOS.

  4. Slc26A9 - anion exchanger, channel and Na+ transporter

    PubMed Central

    Chang, Min-Hwang; Plata, Consuelo; Zandi-Nejad, Kambiz; Sinđić, Aleksandra; Sussman, Caroline R.; Mercado, Adriana; Broumand, Vadjista; Raghuram, Viswanathan; Mount, David B.; Romero, Michael F.

    2009-01-01

    The SLC26 gene family encodes anion transporters with diverse functional attributes: (a) anion exchanger, (b) anion sensor and (c) anion conductance (likely channel). We have cloned and studied Slc26a9, a paralog expressed mostly in lung and stomach. Immunohistochemistry shows that Slc26a9 is present at apical and intracellular membranes of lung and stomach epithelia. Using expression in Xenopus laevis oocytes and ion-sensitive microelectrodes, we discovered that Slc26a9 has a novel function not found in any other Slc26 proteins – cation coupling. Intracellular pH and voltage measurements show that Slc26a9 is a nCl--HCO3- exchanger, suggesting roles in gastric HCl secretion or pulmonary HCO3- secretion; Na+ electrodes and uptakes reveal that Slc26a9 has a cation-dependence. Single channel measurements indicate that Slc26a9 displays discrete open and close states. These experiments show that Slc26a9 has three discrete physiological modes: nCl--HCO3- exchanger, Cl- channel, and Na+-anion cotransporter. Thus, the Slc26a9 transporter-channel is uniquely suited for dynamic and tissue-specific physiology or regulation in epithelial tissues. PMID:19365592

  5. Lyotropic anions. Na channel gating and Ca electrode response

    PubMed Central

    1983-01-01

    The effects of external anions on gating of Na channels of frog skeletal muscle were studied under voltage clamp. Anions reversibly shift the voltage dependence of peak sodium permeability and of steady state sodium inactivation towards more negative potentials in the sequence: methanesulfonate less than or equal to Cl- less than or equal to acetate less than Br- less than or equal to NO-3 less than or equal to SO2-4 less than benzenesulfonate less than SCN- less than ClO-4; approximately the lyotropic sequence. Voltage shifts are graded with mole fraction in mixtures and are roughly additive to calcium shifts. The peak PNa is not greatly affected. Except for SO2-4, these anions did not change the Ca++ activity of the solutions as measured with the dye murexide. Shifts of gating can be explained as the electrostatic effect of anion adsorption to the Na channel or to nearby lipid. Such adsorption is expected to follow the lyotropic series. Anions also interfere significantly with the response of a Ca-sensitive membrane electrode following the same sequence of effectiveness as the shifts of gating. The lyotropic anions decrease the Ca++ sensitivity and cause anomalously negative responses of the Ca electrode because these anions are somewhat permeant in the hydrophobic detector membrane. PMID:6302198

  6. NaOH-modified ceramic honeycomb with enhanced formaldehyde adsorption and removal performance.

    PubMed

    Yu, Jiaguo; Li, Xinyang; Xu, Zhihua; Xiao, Wei

    2013-09-01

    NaOH-modified ceramic honeycombs (Na-CH) were simply prepared by impregnating ceramic honeycombs (CH) into NaOH aqueous solution. It was clearly shown that the surface modification incurs higher specific surface area and smaller grain sizes of the CH without destruction of their integrity. Moreover, the introduced surface NaOH can trigger Cannizzaro disproportionation of surface-absorbed formaldehyde (HCHO) on Na-CH, resulting in catalytic transformation of HCHO into less-toxic formate and methoxy salts. The NaOH concentration during impregnating treatment has a great influence on HCHO adsorption and removal efficiency, while the impregnation time and temperature have little influence on the efficiency. When the CH was impregnated in 1 M NaOH aqueous solution for 0.5 h at room temperature, the HCHO removal efficiency at ambient temperature can reach about 80% with an initial HCHO concentration of 250 ppm. Moreover, the used Na-CH can be facilely regenerated via 1 min blow using a common electric hair dryer, with the generation of less toxic HCOOH and CH3OH and recovery of NaOH. Using such a mild, fast, and practical regeneration method, the regenerated Na-CH showed slight degradation in adsorption and removal capability toward HCHO. The enhanced performance of Na-CH obtained was attributed to the presence of NaOH and increase of specific surface area and surface hydroxyl groups. Considering no demand of noble metal for HCHO removal at ambient temperature and practical reusable capability of Na-CH under mild conditions, this work may provide some new insights into the design and fabrication of advanced catalysts for indoor air purification.

  7. Characterization of Na+ uptake in the endangered desert pupfish, Cyprinodon macularius (Baird and Girard)

    PubMed Central

    Brix, Kevin V.; Grosell, Martin

    2013-01-01

    This study provided an initial characterization of Na+ uptake in saline freshwater by the endangered pupfish, Cyprinodon macularius. This species occurs only in several saline water systems in the southwestern USA and northern Mexico, where salinity is largely controlled by water-management practices. Consequently, understanding the osmoregulatory capacity of this species is important for their conservation. The lower acclimation limit of C. macularius in freshwater was found to be 2 mM Na+. Fish acclimated to 2 or 7 mM Na+ displayed similar Na+ uptake kinetics, with Km values of 4321 and 3672 μM and Vmax values of 4771 and 3602 nmol g−1 h−1, respectively. A series of experiments using pharmacological inhibitors indicated that Na+ uptake in C. macularius was not sensitive to bumetanide, metolazone, or phenamil. These results indicate the Na+–K+–2Cl− cotransporter, Na+–Cl− cotransporter, and the Na+ channel–H+-ATPase system are likely not to be involved in Na+ uptake at the apical membrane of fish gill ionocytes in fish acclimated to 2 or 7 mM Na+. However, Na+ uptake was sensitive to 1 × 10−3 M amiloride (not 1 × 10−4 or 1 × 10−5 M), 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), and ethoxzolamide. These data suggest that C. macularius relies on a low-affinity Na+–H+ exchanger for apical Na+ uptake and that H+ ions generated via carbonic anhydrase-mediated CO2 hydration are important for the function of this protein. PMID:27293589

  8. Linking salinity stress tolerance with tissue-specific Na+ sequestration in wheat roots

    PubMed Central

    Wu, Honghong; Shabala, Lana; Liu, Xiaohui; Azzarello, Elisa; Zhou, Meixue; Pandolfi, Camilla; Chen, Zhong-Hua; Bose, Jayakumar; Mancuso, Stefano; Shabala, Sergey

    2015-01-01

    Salinity stress tolerance is a physiologically complex trait that is conferred by the large array of interacting mechanisms. Among these, vacuolar Na+ sequestration has always been considered as one of the key components differentiating between sensitive and tolerant species and genotypes. However, vacuolar Na+ sequestration has been rarely considered in the context of the tissue-specific expression and regulation of appropriate transporters contributing to Na+ removal from the cytosol. In this work, six bread wheat varieties contrasting in their salinity tolerance (three tolerant and three sensitive) were used to understand the essentiality of vacuolar Na+ sequestration between functionally different root tissues, and link it with the overall salinity stress tolerance in this species. Roots of 4-day old wheat seedlings were treated with 100 mM NaCl for 3 days, and then Na+ distribution between cytosol and vacuole was quantified by CoroNa Green fluorescent dye imaging. Our major observations were as follows: (1) salinity stress tolerance correlated positively with vacuolar Na+ sequestration ability in the mature root zone but not in the root apex; (2) contrary to expectations, cytosolic Na+ levels in root meristem were significantly higher in salt tolerant than sensitive group, while vacuolar Na+ levels showed an opposite trend. These results are interpreted as meristem cells playing a role of the “salt sensor;” (3) no significant difference in the vacuolar Na+ sequestration ability was found between sensitive and tolerant groups in either transition or elongation zones; (4) the overall Na+ accumulation was highest in the elongation zone, suggesting its role in osmotic adjustment and turgor maintenance required to drive root expansion growth. Overall, the reported results suggest high tissue-specificity of Na+ uptake, signaling, and sequestration in wheat roots. The implications of these findings for plant breeding for salinity stress tolerance are discussed

  9. Transient state kinetic evidence for an oligomer in the mechanism of Na sup + -H sup + exchange

    SciTech Connect

    Otsu, K.; Kinsella, J.; Sacktor, B.; Froehlich, J.P. )

    1989-07-01

    Pre-steady-state kinetic measurements of {sup 22}Na{sup +} uptake by the amiloride-sensitive Na{sup +}-H{sup +} exchanger in renal brush border membrane vesicles (BBMV) were performed at 0{degree}C to characterize the intermediate reactions of the exchange cycle. At 1 mM Na{sup +}, the initial time course of Na{sup +} uptake was resolved into three separate components: (i) a lag phase, (ii) an exponential or burst phase, and (iii) a constant velocity or steady-state phase. Pulse-chase experiments using partially loaded BBMV showed no evidence for {sup 22}Na{sup +} backflux, suggesting that the decline in the rate of Na{sup +} uptake rate following the burst represents completion of the first turnover of the exchanger. Gramicidin completely abolished Na{sup +} uptake, indicating that the burst phase results from the translocation of Na{sup +} rather than from residual Na{sup +} binding to external sites. Raising the (Na{sup +}) from 1 to 10 mM at constant pH produced a sigmoidal increase in the amplitude of the burst phase without affecting the lag duration or the apparent burst rate. These results suggest that a minimum of two Na{sup +} transport sites must be occupied to activate Na{sup +} uptake in the pre-steady state. The transition to Michaelis-Menten kinetics in the steady state can be explained by a flip-flop or alternating site mechanism in which the functional transport unit is an oligomer and only one protomer per cycle is allowed to form a translocation complex with Na{sup +} after the first turnover.

  10. Na-Ion Battery Anodes: Materials and Electrochemistry.

    PubMed

    Luo, Wei; Shen, Fei; Bommier, Clement; Zhu, Hongli; Ji, Xiulei; Hu, Liangbing

    2016-02-16

    The intermittent nature of renewable energy sources, such as solar and wind, calls for sustainable electrical energy storage (EES) technologies for stationary applications. Li will be simply too rare for Li-ion batteries (LIBs) to be used for large-scale storage purposes. In contrast, Na-ion batteries (NIBs) are highly promising to meet the demand of grid-level storage because Na is truly earth abundant and ubiquitous around the globe. Furthermore, NIBs share a similar rocking-chair operation mechanism with LIBs, which potentially provides high reversibility and long cycling life. It would be most efficient to transfer knowledge learned on LIBs during the last three decades to the development of NIBs. Following this logic, rapid progress has been made in NIB cathode materials, where layered metal oxides and polyanionic compounds exhibit encouraging results. On the anode side, pure graphite as the standard anode for LIBs can only form NaC64 in NIBs if solvent co-intercalation does not occur due to the unfavorable thermodynamics. In fact, it was the utilization of a carbon anode in LIBs that enabled the commercial successes. Anodes of metal-ion batteries determine key characteristics, such as safety and cycling life; thus, it is indispensable to identify suitable anode materials for NIBs. In this Account, we review recent development on anode materials for NIBs. Due to the limited space, we will mainly discuss carbon-based and alloy-based anodes and highlight progress made in our groups in this field. We first present what is known about the failure mechanism of graphite anode in NIBs. We then go on to discuss studies on hard carbon anodes, alloy-type anodes, and organic anodes. Especially, the multiple functions of natural cellulose that is used as a low-cost carbon precursor for mass production and as a soft substrate for tin anodes are highlighted. The strategies of minimizing the surface area of carbon anodes for improving the first-cycle Coulombic efficiency are

  11. Na-Ion Battery Anodes: Materials and Electrochemistry.

    PubMed

    Luo, Wei; Shen, Fei; Bommier, Clement; Zhu, Hongli; Ji, Xiulei; Hu, Liangbing

    2016-02-16

    The intermittent nature of renewable energy sources, such as solar and wind, calls for sustainable electrical energy storage (EES) technologies for stationary applications. Li will be simply too rare for Li-ion batteries (LIBs) to be used for large-scale storage purposes. In contrast, Na-ion batteries (NIBs) are highly promising to meet the demand of grid-level storage because Na is truly earth abundant and ubiquitous around the globe. Furthermore, NIBs share a similar rocking-chair operation mechanism with LIBs, which potentially provides high reversibility and long cycling life. It would be most efficient to transfer knowledge learned on LIBs during the last three decades to the development of NIBs. Following this logic, rapid progress has been made in NIB cathode materials, where layered metal oxides and polyanionic compounds exhibit encouraging results. On the anode side, pure graphite as the standard anode for LIBs can only form NaC64 in NIBs if solvent co-intercalation does not occur due to the unfavorable thermodynamics. In fact, it was the utilization of a carbon anode in LIBs that enabled the commercial successes. Anodes of metal-ion batteries determine key characteristics, such as safety and cycling life; thus, it is indispensable to identify suitable anode materials for NIBs. In this Account, we review recent development on anode materials for NIBs. Due to the limited space, we will mainly discuss carbon-based and alloy-based anodes and highlight progress made in our groups in this field. We first present what is known about the failure mechanism of graphite anode in NIBs. We then go on to discuss studies on hard carbon anodes, alloy-type anodes, and organic anodes. Especially, the multiple functions of natural cellulose that is used as a low-cost carbon precursor for mass production and as a soft substrate for tin anodes are highlighted. The strategies of minimizing the surface area of carbon anodes for improving the first-cycle Coulombic efficiency are

  12. Involvement of Na+ in Active Uptake of Pyruvate in Mesophyll Chloroplasts of Some C4 Plants 1

    PubMed Central

    Ohnishi, Jun-ichi; Flügge, Ulf-Ingo; Heldt, Hans W.; Kanai, Ryuzi

    1990-01-01

    An artificial Na+ gradient across the envelope (Na+ jump) enhanced pyruvate uptake in the dark into mesophyll chloroplasts of a C4 plant, Panicum miliaceum (NAD-malic enzyme type) (J Ohnishi, R Kanai [1987] FEBS Lett 219:347). In the present study, 22Na+ and pyruvate uptake were examined in mesophyll chloroplasts of several species of C4 plants. Enhancement of pyruvate uptake by a Na+ jump in the dark was also seen in mesophyll chloroplasts of Urochloa panicoides and Panicum maximum (phosphoenolpyruvate carboxykinase types) but not in Zea mays or Sorghum bicolor (NADP-malic enzyme types). In mesophyll chloroplasts of P. miliaceum and P. maximum, pyruvate in turn enhanced Na+ uptake in the dark when added together with Na+. When flux of endogenous Na+ was measured in these mesophyll chloroplasts preincubated with 22Na+, pyruvate addition induced Na+ influx, and the extent of the pyruvate-induced Na+ influx positively correlated with that of pyruvate uptake. A Na+/H+ exchange ionophore, monensin, nullified all the above mutual effects of Na+ and pyruvate in mesophyll chloroplasts of P. miliaceum, while it accelerated Na+ uptake and increased equilibrium level of chloroplast 22Na+. Measurements of initial uptake rates of pyruvate and Na+ gave a stoichiometry close to 1:1. These results point to Na+/pyruvate cotransport into mesophyll chloroplasts of some C4 plants. PMID:16667876

  13. Expression profiling of sodium butyrate (NaB)-treated cells: identification of regulation of genes related to cytokine signaling and cancer metastasis by NaB.

    PubMed

    Joseph, Jeena; Mudduluru, Giridhar; Antony, Sini; Vashistha, Surabhi; Ajitkumar, Parthasarathi; Somasundaram, Kumaravel

    2004-08-19

    Histone deacetylase (HDAC) inhibitors induce growth arrest and apoptosis in a variety of human cancer cells. Sodium butyrate (NaB), a short chain fatty acid, is a HDAC inhibitor and is produced in the colonic lumen as a consequence of microbial degradation of dietary fibers. In order to dissect out the mechanism of NaB-induced growth inhibition of cancer cells, we carried out expression profiling of a human lung carcinoma cell line (H460) treated with NaB using a cDNA microarray. Of the total 1728 genes analysed, there were 32 genes with a mean expression value of 2.0-fold and higher and 66 genes with a mean expression value 3.0-fold and lower in NaB-treated cells. For a few selected genes, we demonstrate that their expression pattern by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis is matching with the results obtained by microarray analysis. Closer view at the expression profile of NaB-treated cells revealed the downregulation of a total of 16 genes associated with cytokine signaling, in particular, interferon gamma (IFNgamma) pathway. In good correlation, NaB-pretreated cells failed to induce interferon regulatory factor 1, an INFgamma target gene, efficiently upon IFNgamma addition. These results suggest that NaB inhibits proinflammatory cytokine signaling pathway, thus providing proof of mechanism for its anti-inflammatory activity. We also found that NaB induced three genes, which are known metastatic suppressors, and downregulated 11 genes, which have been shown to promote metastasis. Upregulation of metastatic suppressor Kangai 1 (KAI1) by NaB in a time-dependent manner was confirmed by RT-PCR analysis. The differential regulation of metastasis-associated genes by NaB provides explanation for the anti-invasive properties of NaB. Therefore, our study presents new evidence for pathways regulated by NaB, thus providing evidence for the mechanism behind anti-inflammatory and antimetastatic activities of NaB.

  14. Differential regulation of the renal sodium-phosphate cotransporters NaPi-IIa, NaPi-IIc, and PiT-2 in dietary potassium deficiency.

    PubMed

    Breusegem, Sophia Y; Takahashi, Hideaki; Giral-Arnal, Hector; Wang, Xiaoxin; Jiang, Tao; Verlander, Jill W; Wilson, Paul; Miyazaki-Anzai, Shinobu; Sutherland, Eileen; Caldas, Yupanqui; Blaine, Judith T; Segawa, Hiroko; Miyamoto, Ken-ichi; Barry, Nicholas P; Levi, Moshe

    2009-08-01

    Dietary potassium (K) deficiency is accompanied by phosphaturia and decreased renal brush border membrane (BBM) vesicle sodium (Na)-dependent phosphate (P(i)) transport activity. Our laboratory previously showed that K deficiency in rats leads to increased abundance in the proximal tubule BBM of the apical Na-P(i) cotransporter NaPi-IIa, but that the activity, diffusion, and clustering of NaPi-IIa could be modulated by the altered lipid composition of the K-deficient BBM (Zajicek HK, Wang H, Puttaparthi K, Halaihel N, Markovich D, Shayman J, Beliveau R, Wilson P, Rogers T, Levi M. Kidney Int 60: 694-704, 2001; Inoue M, Digman MA, Cheng M, Breusegem SY, Halaihel N, Sorribas V, Mantulin WW, Gratton E, Barry NP, Levi M. J Biol Chem 279: 49160-49171, 2004). Here we investigated the role of the renal Na-P(i) cotransporters NaPi-IIc and PiT-2 in K deficiency. Using Western blotting, immunofluorescence, and quantitative real-time PCR, we found that, in rats and in mice, K deficiency is associated with a dramatic decrease in the NaPi-IIc protein abundance in proximal tubular BBM and in NaPi-IIc mRNA. In addition, we documented the presence of a third Na-coupled P(i) transporter in the renal BBM, PiT-2, whose abundance is also decreased by dietary K deficiency in rats and in mice. Finally, electron microscopy showed subcellular redistribution of NaPi-IIc in K deficiency: in control rats, NaPi-IIc immunolabel was primarily in BBM microvilli, whereas, in K-deficient rats, NaPi-IIc BBM label was reduced, and immunolabel was prevalent in cytoplasmic vesicles. In summary, our results demonstrate that decreases in BBM abundance of the phosphate transporter NaPi-IIc and also PiT-2 might contribute to the phosphaturia of dietary K deficiency, and that the three renal BBM phosphate transporters characterized so far can be differentially regulated by dietary perturbations.

  15. Potassium depletion increases luminal Na+/H+ exchange and basolateral Na+:CO3=:HCO3- cotransport in rat renal cortex

    SciTech Connect

    Soleimani, M.; Bergman, J.A.; Hosford, M.A.; McKinney, T.D. )

    1990-10-01

    Most HCO3- reabsorption in proximal tubules occurs via electroneutral Na+/H+ exchange in brush border membranes (BBMS) and electrogenic Na+:CO3=:HCO3- cotransport in basolateral membranes (BLMS). Since potassium depletion (KD) increases HCO3- reabsorption in proximal tubules, we evaluated these transport systems using BBM and BLM vesicles, respectively, from control (C) and KD rats. Feeding rats a potassium deficient diet for 3-4 wk resulted in lower plasma (K+) (2.94 mEq/liter, KD vs. 4.47 C), and higher arterial pH (7.51 KD vs. 7.39 C). KD rats gained less weight than C but had higher renal cortical weight. Influx of 1 mM 22Na+ at 5 s (pHo 7.5, pHi 6.0, 10% CO2, 90% N2) into BLM vesicles was 44% higher in the KD group compared to C with no difference in equilibrium uptake. The increment in Na+ influx in the KD group was DIDS sensitive, suggesting that Na+:CO3=:HCO3- cotransport accounted for the observed differences. Kinetic analysis of Na+ influx showed a Km of 8.2 mM in KD vs. 7.6 mM in C and Vmax of 278 nmol/min/mg protein in KD vs. 177 nmol/min/mg protein in C. Influx of 1 mM 22Na+ at 5 s (pHo 7.5, pHi 6.0) into BBM vesicles was 34% higher in the KD group compared to C with no difference in equilibrium uptake. The increment in Na+ influx in the KD group was amiloride sensitive, suggesting that Na+/H+ exchange was responsible for the observed differences. Kinetic analysis of Na+ influx showed a Km of 6.2 mM in KD vs. 7.1 mM in C and Vmax of 209 nmol/min/mg protein in KD vs. 144 nmol/min/mg protein in C. Uptakes of Na(+)-dependent (3H)glucose into BBM and (14C)succinate into BLM vesicles were not different in KD and C groups, suggesting that the Na+/H+ exchanger and Na+:CO3=:HCO3- cotransporter activities were specifically altered in KD.

  16. Identification of a 3rd Na+ Binding Site of the Glycine Transporter, GlyT2

    PubMed Central

    Subramanian, Nandhitha; Scopelitti, Amanda J.; Carland, Jane E.; Ryan, Renae M.; O’Mara, Megan L.; Vandenberg, Robert J.

    2016-01-01

    The Na+/Cl- dependent glycine transporters GlyT1 and GlyT2 regulate synaptic glycine concentrations. Glycine transport by GlyT2 is coupled to the co-transport of three Na+ ions, whereas transport by GlyT1 is coupled to the co-transport of only two Na+ ions. These differences in ion-flux coupling determine their respective concentrating capacities and have a direct bearing on their functional roles in synaptic transmission. The crystal structures of the closely related bacterial Na+-dependent leucine transporter, LeuTAa, and the Drosophila dopamine transporter, dDAT, have allowed prediction of two Na+ binding sites in GlyT2, but the physical location of the third Na+ site in GlyT2 is unknown. A bacterial betaine transporter, BetP, has also been crystallized and shows structural similarity to LeuTAa. Although betaine transport by BetP is coupled to the co-transport of two Na+ ions, the first Na+ site is not conserved between BetP and LeuTAa, the so called Na1' site. We hypothesized that the third Na+ binding site (Na3 site) of GlyT2 corresponds to the BetP Na1' binding site. To identify the Na3 binding site of GlyT2, we performed molecular dynamics (MD) simulations. Surprisingly, a Na+ placed at the location consistent with the Na1' site of BetP spontaneously dissociated from its initial location and bound instead to a novel Na3 site. Using a combination of MD simulations of a comparative model of GlyT2 together with an analysis of the functional properties of wild type and mutant GlyTs we have identified an electrostatically favorable novel third Na+ binding site in GlyT2 formed by Trp263 and Met276 in TM3, Ala481 in TM6 and Glu648 in TM10. PMID:27337045

  17. A study on absorption of Na atoms on Si(100) 2×1 surfaces with DV-Xα method

    NASA Astrophysics Data System (ADS)

    Shi-hong, Xu; Peng-shou, Xu; Jia, Li; Mao-sheng, Ma; Yu-heng, Zhang; Zhen-jia, Xu

    1993-10-01

    The Na absorption on Si(100) 2×1 surface is studied with quantum chemistry molecular cluster method. The calculated results show that the most favourable absorption site of Na is the cave site and the charge transfer of Na atom to Si is large when the Na coverage is smaller than 0.5 monolayer (ML). A Na chain is formed along the cave sites at the 0.5 ML Na coverage, the charge transfer then becomes small. The calculated density of states show that the Na atoms are metallic along the chain. At 1 ML coverage, the Na atoms occupy both the cave and pedestal sites and form a double-layer. There is a charge transfer of 0.5e from each Na atom to the Si surface. The calculated surface energy shows that the saturation absorption of Na on Si surface is 1 ML.

  18. Two forms of sodium titanium(III) diphosphate: α-NaTiP 2O 7 closely related to β-cristobalite and β-NaTiP 2O 7 isotypic with NaFeP 2O 7

    NASA Astrophysics Data System (ADS)

    Leclaire, A.; Benmoussa, A.; Borel, M. M.; Grandin, A.; Raveau, B.

    1988-12-01

    The structures of two new forms of a titanium(III) phosphate NaTiP 2O 7 have been determined. One of them, β-NaTiP 2O 7 [ a = 7.394(1)Å, b = 7.936(3)Å, c = 9.726(3)Å β = 11.85(2)° {P2 1}/{c}], is isotypic with NaFeP 2O 7 which has been previously described. The other form, α-NaTiP 2O 7 [ a = 8.697(1)Å, b = 5.239(7)Å, c = 13.293(3)Å, β = 116.54(1)°, {P2 1}/{c}], is found to be closely related to the structure of β-cristobalite and of carnegieite and is described as a "pseudo-hexagonal" framework characterized by intersecting tunnels.

  19. Complexation of pectin with macro- and microelements. Antianemic activity of Na, Fe and Na, Ca, Fe complexes.

    PubMed

    Minzanova, S T; Mironov, V F; Vyshtakalyuk, A B; Tsepaeva, O V; Mironova, L G; Mindubaev, A Z; Nizameev, I R; Kholin, K V; Milyukov, V A

    2015-12-10

    New water-soluble pectin complexes with Ca(2+), Mg(2+), Co(2+), Cu(2+), Fe(2+), Mn(2+), Zn(2+) on the basis of pectin biopolymer have been synthesized and successfully tested on white rats. For a starting, we have obtained a sodium pectate to enhance solubility of target complexes as a whole. Shortly afterwards, running the reaction of ligand exchange of Nа(+) ions with corresponding s-, d- metal cations we were able to synthesize new pectin complexes. The ranges of s-, d-metals salts concentrations were detected experimentally, in which the selective formation of water-soluble complexes occurred. Antianemic effect of new pectin complexes with Na, Fe and Na, Ca, Fe was investigated on white rats with posthemorrhagic anemia. Under the effect of complexes, the improvement of animals and prevention of erythropoiesis disorders were observed. Antianemic effect of the complexes manifested itself in the doses equivalent to 25% or 50% of the iron daily rate, recommended in the treatment of iron-deficiency anemia with the drugs based on iron sulphate. PMID:26428154

  20. SNaRIs, NaSSAs, and NaRIs: new agents for the treatment of depression.

    PubMed

    Kent, J M

    2000-03-11

    A major goal of antidepressant development is to improve on preceding drug classes with agents with greater specificity (and therefore fewer unwanted side-effects) and with more rapid onset of antidepressant action. To this end, four antidepressants with significantly distinct pharmacological characteristics have been recently introduced: venlafaxine, nefazodone, mirtazapine, and reboxetine. Venlafaxine is the first antidepressant in a new drug class referred to as the serotonin noradrenergic reuptake inhibitors (SNaRIs). Nefazodone is a weaker serotonin and norepinephrine reuptake inhibitor, but a potent serotonin 5-HT2 receptor antagonist. Mirtazapine is a potent antagonist of central 2alpha-adrenergic autoreceptors, and heteroreceptors and is an antagonist of serotonin 5-HT2 and 5-HT3 receptors. The result of these actions is to increase both noradrenergic and specific (5-HT1) serotonergic transmission, and mirtazapine has therefore been termed a noradrenergic and specific serotonergic antidepressant (NaSSA). Reboxetine is the first selective noradrenaline reuptake inhibitor (NaRI) to be introduced since the tricyclics, and lacks immediate serotonergic effects. PMID:10752718

  1. Electronic structures and second hyperpolarizabilities of alkaline earth metal complexes end-capped with NA2 (A = H, Li, Na).

    PubMed

    Banerjee, Paramita; Nandi, Prasanta K

    2016-05-14

    The ground state structures and NLO properties of a number of alkaline earth metal complexes end-capped with NA2 groups (A = H, Li, Na) are calculated by employing the CAM-B3LYP, wB97XD and B2PLYP functionals along with MP2 and CCSD(T) for 6-311++G(d,p), 6-311++G(3df,3pd), aug-cc-pVTZ, aug-pc-2 and Hypol basis sets. The complexes are found to be significantly stable. The magnitude of second hyperpolarizability enhances appreciably with increase in the number of magnesium and calcium atoms in the chain, which has been indicated by the power law dependence γ = a + bn(c) with c values ranging from 2.4-4.3 for Mg and 2.4-3.7 for Ca complexes, respectively. The largest second-hyperpolarizability (10(9) au) is obtained for the complex Ca7(NNa2)2 at the CAM-B3LYP level. The two state model has been used to explain the variation of hyperpolarizabilities. PMID:27088138

  2. Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na3OBr and Na4OI2

    NASA Astrophysics Data System (ADS)

    Wang, Yonggang; Wen, Ting; Park, Changyong; Kenney-Benson, Curtis; Pravica, Michael; Yang, Wenge; Zhao, Yusheng

    2016-01-01

    The structure stability under high pressure and thermal expansion behavior of Na3OBr and Na4OI2, two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na3OBr and Na4OI2, respectively. The cubic Na3OBr structure and tetragonal Na4OI2 with intergrowth K2NiF4 structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na4OI2 exhibits nearly isotropic compressibility. Negative thermal expansion was observed at low temperature range (20-80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications.

  3. Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl.

    PubMed

    Reginato, M; Sosa, L; Llanes, A; Hampp, E; Vettorazzi, N; Reinoso, H; Luna, V

    2014-01-01

    Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na(+) accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K(+) supply by maintaining high K(+)/Na(+) discrimination, and maintenance of normal Ca(2+) levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO4(2-)-induced toxicity by Cl(-). Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments.

  4. A Ca substitution study of NaV2O4: High-pressure synthesis of the Na1-xCaxV2O4 solid solution

    SciTech Connect

    Varga, Tamas; Mitchell, John F.; Yamaura, Kazunari; Mandrus, David; Wang, Jun

    2009-01-01

    Ambient pressure CaV{sub 2}O{sub 4} and high-pressure NaV{sub 2}O{sub 4} crystallize in the CaFe{sub 2}O{sub 4} structure type containing double chains of edge-sharing VO{sub 6} octahedra. Recent measurements on NaV{sub 2}O{sub 4} reveal low-dimensional metallicity and evidence of half-metallic ferromagnetism. In contrast, CaV{sub 2}O{sub 4} is an antiferromagnetic insulator. To explore the evolution of these ground-state behaviors, we have prepared a series of Ca-doped NaV{sub 2}O{sub 4} compounds with the formula Na{sub 1-x}Ca{sub x}V{sub 2}O{sub 4} (x = 0-1) using high-pressure synthesis. Samples at the Na end (x = 0-0.07) show a broad antiferromagnetic transition in the 120-160 K range in accordance with earlier reports. Transport measurements show an insulator-metal transition at x {approx} 0.2. Samples with higher Ca concentrations (x = 0.4-0.7) exhibit a metal-insulator transition around 150 K. The results for the Na{sub 1-x}Ca{sub x}V{sub 2}O{sub 4} solid solution is discussed in comparison to existing studies at the Ca- and Na-rich ends.

  5. Proteins which mediate the nuclear entry of goat uterine non activated estrogen receptor (naER) following naER internalization from the plasma membrane.

    PubMed

    Sreeja, S; Thampan, Raghava Varman

    2004-04-01

    The nuclear transport of the internalised naER is influenced by a 58 kDa protein, p58, that appears to recognize the nuclear localization signals on the naER. At the nuclear pore complex the naER-p58 complex binds to a 62 kDa protein, p62; p58 recognizes p62 in this interaction. It is further observed that p62 gets 'docked' at a 66 kDa nuclear pore complex protein, npcp66. The nuclear entry of naER is an ATP-dependent process. An ATP-dependent biphasic nuclear entry of naER, has been observed. It is possible that the docking of p58-naER complex at the nuclear pore complex and the eventual nuclear entry of naER following its dissociation from the p58 are influenced by two different ranges in the concentration of ATP. In this process, it appears that, the nuclear entry requires an additional quantum of energy, provided by the hydrolysed ATP, in contrast to the energy requirement associated with, the nuclear 'docking' event. PMID:15124917

  6. Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl.

    PubMed

    Reginato, M; Sosa, L; Llanes, A; Hampp, E; Vettorazzi, N; Reinoso, H; Luna, V

    2014-01-01

    Halophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso-osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso-osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na(+) accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K(+) supply by maintaining high K(+)/Na(+) discrimination, and maintenance of normal Ca(2+) levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi-saline-treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO4(2-)-induced toxicity by Cl(-). Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments. PMID:23869994

  7. Bundle-like α'-NaV2O5 mesocrystals: from synthesis, growth mechanism to analysis of Na-ion intercalation/deintercalation abilities.

    PubMed

    Liu, Pengcheng; Zhou, Dehua; Zhu, Kongjun; Wu, Qingliu; Wang, Yifeng; Tai, Guoan; Zhang, Wei; Gu, Qilin

    2016-01-28

    Bundle-like α'-NaV2O5 mesocrystals were synthesized successfully by a two-step hydrothermal method. Observations using electron microscopy revealed that the obtained NaV2O5 mesocrystals were composed of nanobelts with the preferential growth direction of [010]. The precise crystal structure was further confirmed by Rietveld refinement and Raman spectroscopy. Based on analysis of crystal structure and microscopy, a reaction and growth mechanism, hydrolysis-condensation (oxolation and olation)-ion exchange-self-assembly, was proposed and described in detail. Furthermore, electrochemical measurements were used to analyze the Na-ions intercalation/deintercalation abilities in NaV2O5, and indicated that Na-ions were difficult to extract. Importantly, the DFT theoretical calculation results, which showed that the migration energy of Na-ions was so huge that migration of Na-ions was quite difficult, can explain and support well the results of the electrochemical measurements. PMID:26673118

  8. NaCo(H2PO2)3: Crystal structure and physical study

    NASA Astrophysics Data System (ADS)

    El Bali, Brahim; Lachkar, Mohammed; Essehli, Rachid; Dusek, Michal; Rohlicek, Jan; Mircescu, Nicoleta; Haisch, Christoph

    2016-11-01

    NaCo(H2PO2)3 was synthesized in solution and its structure was studied by single-crystal X-ray diffraction. It crystallizes in the cubic space group P213 (#198), Z = 4, a = 9.2563(16) Å, V = 793.1(2) Å3. Final residual factors of the refined structure model R/Rw were 0.0367/0.0941. The cations Na+ and Co2+ are both octahedrally coordinated. [NaO6] and [CoO6] share edges to form channels propagating along [1,-1, -1] with the [H2PO2] pseudo-pyramids adjusted inside the channels to the above mentioned octahedra. The IR and Raman spectroscopic studies show the expected bands of the hypophosphite anion. NaCo(H2PO2)3 did not show any electrochemical activity under the electrochemical test conditions (2.4-4.5 V vs. Na/Na+).

  9. 29Na: defining the edge of the island of inversion for Z=11.

    PubMed

    Tripathi, Vandana; Tabor, S L; Mantica, P F; Hoffman, C R; Wiedeking, M; Davies, A D; Liddick, S N; Mueller, W F; Otsuka, T; Stolz, A; Tomlin, B E; Utsuno, Y; Volya, A

    2005-04-29

    The low-energy level structure of the exotic Na isotopes (28,29)Na has been investigated through beta-delayed gamma spectroscopy. The N=20 isotones for Z=10-12 are considered to belong to the "island of inversion" where intruder configurations dominate the ground state wave function. However, it is an open question as to where and how the transition from normal to intruder dominated configurations happens in an isotopic chain. The present work, which presents the first detailed spectroscopy of (28,29)Na, clearly demonstrates that such a transition in the Na isotopes occurs between 28Na (N=17) and 29Na (N=18), supporting the smaller N=20 shell gap in neutron-rich sd shell nuclei. The evidence for inverted shell structure is found in beta-decay branching ratios, intruder dominated spectroscopy of low-lying states, and shell model analysis. PMID:15904217

  10. Mechanism of potassium ion uptake by the Na+/K+-ATPase

    PubMed Central

    Castillo, Juan P.; Rui, Huan; Basilio, Daniel; Das, Avisek; Roux, Benoît; Latorre, Ramon; Bezanilla, Francisco; Holmgren, Miguel

    2015-01-01

    The Na+/K+-ATPase restores sodium (Na+) and potassium (K+) electrochemical gradients dissipated by action potentials and ion-coupled transport processes. As ions are transported, they become transiently trapped between intracellular and extracellular gates. Once the external gate opens, three Na+ ions are released, followed by the binding and occlusion of two K+ ions. While the mechanisms of Na+ release have been well characterized by the study of transient Na+ currents, smaller and faster transient currents mediated by external K+ have been more difficult to study. Here we show that external K+ ions travelling to their binding sites sense only a small fraction of the electric field as they rapidly and simultaneously become occluded. Consistent with these results, molecular dynamics simulations of a pump model show a wide water-filled access channel connecting the binding site to the external solution. These results suggest a mechanism of K+ gating different from that of Na+ occlusion. PMID:26205423

  11. Interaction of oxygen with the (111) surface of NaAu2

    NASA Astrophysics Data System (ADS)

    Kwolek, Emma J.; Widmer, Roland; Gröning, Oliver; Deniz, Okan; Walen, Holly; Yuen, Chad D.; Huang, Wenyu; Schlagel, Deborah L.; Wallingford, Mark; Brundle, C. R.; Thiel, Patricia A.

    2016-08-01

    NaAu2, in powder form, is known to be an active catalyst for CO oxidation. The goal of the present study is to elucidate the interaction of one reactant, molecular oxygen, with a single-crystal surface of this material, NaAu2(111). Exposing the clean surface to gas-phase molecular oxygen produces three types of oxygen on the surface. One type is bound in spurious carbonate that forms during exposure. The second is adsorbed atomic oxygen that interacts both with Na and Au. The third type is atomic oxygen that interacts mainly or only with Na. We propose that the last species is an oxide of Na distributed throughout the surface and near-surface region. Its formation is accompanied by surface segregation of Na.

  12. Significance of Na+ in the fish pathogen, Vibrio anguillarum, under energy depleted condition.

    PubMed

    Fujiwara-Nagata, Erina; Eguchi, Mitsuru

    2004-05-01

    Vibrio anguillarum kills various kinds of fish over salinities ranging from seawater to freshwater. In this study, we investigated the role of Na(+) in V. anguillarum, especially under energy-depleted conditions such as in natural seawater. V. angustum S14, which is a typical marine vibrio, was used for comparison. V. anguillarum only required Na(+) for starvation-survival, but in contrast, V. angustum S14 always required Na(+) for both growth and starvation-survival. In marine vibrios, Na(+) is used in the Na(+)-dependent respiratory chain that produces the sodium motive force (SMF) across the cell membrane. It has been considered that marine vibrios always need a SMF produced by Na(+), however in the case of V. anguillarum, the SMF is not required for growth, but becomes more important for starvation-survival.

  13. Mechanism of potassium ion uptake by the Na(+)/K(+)-ATPase.

    PubMed

    Castillo, Juan P; Rui, Huan; Basilio, Daniel; Das, Avisek; Roux, Benoît; Latorre, Ramon; Bezanilla, Francisco; Holmgren, Miguel

    2015-01-01

    The Na(+)/K(+)-ATPase restores sodium (Na(+)) and potassium (K(+)) electrochemical gradients dissipated by action potentials and ion-coupled transport processes. As ions are transported, they become transiently trapped between intracellular and extracellular gates. Once the external gate opens, three Na(+) ions are released, followed by the binding and occlusion of two K(+) ions. While the mechanisms of Na(+) release have been well characterized by the study of transient Na(+) currents, smaller and faster transient currents mediated by external K(+) have been more difficult to study. Here we show that external K(+) ions travelling to their binding sites sense only a small fraction of the electric field as they rapidly and simultaneously become occluded. Consistent with these results, molecular dynamics simulations of a pump model show a wide water-filled access channel connecting the binding site to the external solution. These results suggest a mechanism of K(+) gating different from that of Na(+) occlusion. PMID:26205423

  14. On the formation of Na nanoparticles in femtosecond-laser irradiated glasses

    SciTech Connect

    Jiang Nan; Su Dong; Spence, John C. H.; Qiu Jianrong

    2010-03-15

    This work discusses the response of Na to both high-energy electrons and femtosecond-laser (fs-laser) pulses in the soda-lime glass. The evidence for different responses of Na to high-energy electron irradiation between glasses with and without fs-laser irradiation suggests that the chemical and/or physical states of Na in the fs-laser irradiated glass are different from those in the original glass. Fs-laser pulses in the glass may be able to neutralize Na, which may form clusters. These results suggest that close attention should be paid to the defects associated with Na when optical or physical data are interpreted in fs-laser irradiated Na glasses.

  15. Cu2Sb thin films as anode for Na-ion batteries

    SciTech Connect

    Baggetto, Loic; Allcorn, Eric; Manthiram, Arumugam; Veith, Gabriel M

    2013-01-01

    Cu2Sb thin films prepared by magnetron sputtering are evaluated as an anode material for Na-ion batteries. The starting material is composed of nanocrystallites with the desired tetragonal P4/nmm structure. The study of the reaction mechanism reveals the formation of an amorphous/nanocrystalline phase of composition close to Na3Sb as the final reaction product. The solid electrolyte interphase (SEI) material is mostly composed of carbonates (Na2CO3, NaCO3R). The Cu2Sb anode possesses moderate capacity retention with a reversible storage capacity (250 mAh/g) close to the theoretical value (323 mAh/g), an average reaction potential of around 0.55 V vs. Na/Na+, and a high rate performance (10 C-rate).

  16. Mechanism of potassium ion uptake by the Na+/K+-ATPase

    NASA Astrophysics Data System (ADS)

    Castillo, Juan P.; Rui, Huan; Basilio, Daniel; Das, Avisek; Roux, Benoît; Latorre, Ramon; Bezanilla, Francisco; Holmgren, Miguel

    2015-07-01

    The Na+/K+-ATPase restores sodium (Na+) and potassium (K+) electrochemical gradients dissipated by action potentials and ion-coupled transport processes. As ions are transported, they become transiently trapped between intracellular and extracellular gates. Once the external gate opens, three Na+ ions are released, followed by the binding and occlusion of two K+ ions. While the mechanisms of Na+ release have been well characterized by the study of transient Na+ currents, smaller and faster transient currents mediated by external K+ have been more difficult to study. Here we show that external K+ ions travelling to their binding sites sense only a small fraction of the electric field as they rapidly and simultaneously become occluded. Consistent with these results, molecular dynamics simulations of a pump model show a wide water-filled access channel connecting the binding site to the external solution. These results suggest a mechanism of K+ gating different from that of Na+ occlusion.

  17. Preparation and characterization of Na-LTA zeolite from Tunisian sand and aluminum scrap

    NASA Astrophysics Data System (ADS)

    Tounsi, H.; Mseddi, S.; Djemel, S.

    2009-11-01

    Pure Na-A (LTA) zeolite has been prepared from aluminosilicate gel obtained by a mixture of metasilicate and aluminate solutions. Metasilicate sol; used as silica source; was prepared from an alkaline attack of Tunisian sand in an autoclave under agitation at 220 ∘C and pressure of 27 bar. The aluminate solution was obtained by dissolution of aluminium scraps in NaOH solution. The crystallization of Na-LTA zeolite is controlled by the alkalinity of the mixture and the reaction time. At 90 ∘C, well crystallized LTA have been obtained after 3h. The Zeolite LTA converts into the more stable HS after long reaction times according to Ostwald's law. The alkalinity of the reaction mixture changes the nature of the obtained zeolite. At lower NaOH concentration (0.1 M), Na-X zeolite was obtained; whereas the crystallization of LTA was promoted at higher NaOH concentration (3M).

  18. Synthesis and assembly of functional mammalian Na,K-ATPase in yeast.

    PubMed

    Horowitz, B; Eakle, K A; Scheiner-Bobis, G; Randolph, G R; Chen, C Y; Hitzeman, R A; Farley, R A

    1990-03-15

    The yeast Saccharomyces cerevisiae was investigated as an in vivo protein expression system for mammalian Na,K-ATPase. Unlike animal cells, yeast cells lack endogenous Na,K-ATPase. Expression of high affinity ouabain binding sites, ouabain-sensitive ATPase activity, or ouabain-sensitive p-nitrophenylphosphatase activity in membrane fractions of yeast cells was observed to require the expression of both alpha subunit and beta subunit polypeptides of Na,K-ATPase in the same cell. High affinity ouabain binding sites are also expressed at the cell surface of intact yeast cells containing both the alpha subunit and the beta subunit of Na,K-ATPase. These observations demonstrate that both the alpha subunit and the beta subunit of Na,K-ATPase are required for the expression of functional Na,K-ATPase activity and that yeast cells can correctly assemble this oligomeric membrane protein and transport it to the cell surface. PMID:1689721

  19. Vasopressin elevation of Na+/H+ exchange is inhibited by genistein in human blood platelets.

    PubMed

    Aharonovits, O; Zik, M; Livne, A A; Granot, Y

    1992-12-01

    The regulation of intracellular Na+ and pHi in human blood platelets is known to be controlled by the function of the Na+/H+ exchanger. The phosphorylation state of the Na+/H+ exchanger which determines the exchanger activity in human blood platelets is regulated by the activities of protein kinases and protein phosphatases. Observations in this study indicate that arginine vasopressin (AVP) that interacts with a V1 receptor, activates the Na+/H+ exchange in human blood platelets through a genistein-inhibited mechanism. The AVP-activated Na+/H+ exchange is probably not regulated by protein kinase C (PKC), since this activation is not inhibited by staurosporine. The multiple ways in which platelet Na+/H+ exchange can be modulated may indicate the critical role played by this exchanger in the homeostasis control of pHi in human blood platelets.

  20. Formation of Frustrated Lewis Pairs in Ptx -Loaded Zeolite NaY.

    PubMed

    Lee, Heeju; Choi, Yong Nam; Lim, Dae-Woon; Rahman, Md Mahbubur; Kim, Yong-Il; Cho, In Hwa; Kang, Hyun Wook; Seo, Jung-Hye; Jeon, Cheolho; Yoon, Kyung Byung

    2015-10-26

    The formation of a frustrated Lewis pair consisting of sodium hydride (Na(+) H(-) ) and a framework-bound hydroxy proton O(H(+) ) is reported upon H2 treatment of zeolite NaY loaded with Pt nanoparticles (Ptx /NaY). Frustrated Lewis pair formation was confirmed using in situ neutron diffraction and spectroscopic measurements. The activity of the intrazeolite NaH as a size-selective catalyst was verified by the efficient esterification of acetaldehyde (a small aldehyde) to form the corresponding ester ethyl acetate, whereas esterification of the larger molecule benzaldehyde was unsuccessful. The frustrated Lewis pair (consisting of Na(+) H(-) and O(H(+) )) generated within zeolite NaY may be a useful catalyst for various catalytic reactions which require both H(-) and H(+) ions, such as catalytic hydrogenation or dehydrogenation of organic compounds and activation of small molecules. PMID:26480339

  1. Tetrodotoxin-resistant sodium channels Na(v)1.8/SNS and Na(v)1.9/NaN in afferent neurons innervating urinary bladder in control and spinal cord injured rats.

    PubMed

    Black, Joel A; Cummins, Theodore R; Yoshimura, Naoki; de Groat, William C; Waxman, Stephen G

    2003-02-14

    Tetrodotoxin-resistant (TTX-R) sodium channels Na(v)1.8/SNS and Na(v)1.9/NaN are preferentially expressed in small diameter dorsal root ganglia (DRG) neurons. The urinary bladder is innervated by small afferent neurons from L6/S1 DRG, of which approximately 75% exhibit high-threshold action potentials that are mediated by TTX-R sodium channels. Following transection of the spinal cord at T8, the bladder becomes areflexic and then gradually hyper-reflexic, and there is an attenuation of the TTX-R sodium currents in bladder afferent neurons. In the present study, we demonstrate that Na(v)1.8 is expressed in both bladder and non-bladder afferent neurons, while Na(v)1.9 is expressed in non-bladder afferent neurons but is rarely observed in bladder afferent neurons. In spinal cord transected rats 28-32 days following transection, there is a decreased expression of Na(v)1.8 sodium channels in bladder afferents, but no change in the expression of Na(v)1.8 in non-bladder afferent neurons. Both bladder and non-bladder afferent neurons exhibit limited increases in Na(v)1.9 expression following spinal cord transection. These results demonstrate that the expression of TTX-R channels in bladder afferent neurons changes after spinal cord transection, and these changes may contribute to the increased excitability of these neurons following spinal cord injury. PMID:12560118

  2. Neuronal Na+ Channels Are Integral Components of Pro-arrhythmic Na+/Ca2+ Signaling Nanodomain That Promotes Cardiac Arrhythmias During β-adrenergic Stimulation

    PubMed Central

    Radwański, Przemysław B.; Ho, Hsiang-Ting; Veeraraghavan, Rengasayee; Brunello, Lucia; Liu, Bin; Belevych, Andriy E.; Unudurthi, Sathya D.; Makara, Michael A.; Priori, Silvia G.; Volpe, Pompeo; Armoundas, Antonis A.; Dillmann, Wolfgang H.; Knollmann, Bjorn C.; Mohler, Peter J.; Hund, Thomas J.; Györke, Sándor

    2016-01-01

    Background Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca2+ and Na+ handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. Methods and Results We performed functional and structural studies to assess Ca2+ and Na+ signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) that colocalize with RyR2 and Na+/Ca2+ exchanger (NCX) are a part of the β-AR-mediated arrhythmogenic process. Specifically, augmented Na+ entry via nNav in the settings of genetic defects within the RyR2 complex and enhanced sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA)-mediated SR Ca2+ refill is both an essential and a necessary factor for the arrhythmogenesis. Furthermore, we show that augmentation of Na+ entry involves β-AR-mediated activation of CAMKII subsequently leading to nNav augmentation. Importantly, selective pharmacological inhibition as well as silencing of Nav1.6 inhibit myocyte arrhythmic potential and prevent arrhythmias in vivo. Conclusion These data suggest that the arrhythmogenic alteration in Na+/Ca2+ handling evidenced ruing β-AR stimulation results, at least in part, from enhanced Na+ influx through nNav. Therefore, selective inhibition of these channels and Nav1.6 in particular can serve as a potential antiarrhythmic therapy. PMID:27747307

  3. Actinic EUV mask inspection beyond 0.25 NA

    SciTech Connect

    Goldberg, Kenneth A.; Mochi, Iacopo; Anderson, Erik H.; Rekawa, Seno B.; Kemp, Charles D.; Huh, S.; Han, H.-S.

    2008-08-06

    Operating at EUV wavelengths, the SEMATECH Berkeley Actinic Inspection Tool (AIT) is a zoneplate microscope that provides high quality aerial image measurements in routine operations for SEMATECH member companies. We have upgraded the optical performance of the AIT to provide multiple image magnifications, and several inspection NA values up to 0.35 NA equivalent (0.0875 mask-side). We report on the improved imaging capabilities including resolution below 100-nm on the mask side (25 nm, 4x wafer equivalent). EUV reticles are intricate optical systems made from of several materials with wavelength-specific optical properties. The combined interactions of the substrate, multilayer-stack, buffer layer and absorber layer produce a reflected EUV optical field that is challenging to model accurately, and difficult to fully assess without actinic at-wavelength inspection. Understanding the aerial image from lithographic printing alone is complicated by photoresist properties. The AIT is now used to investigate mask issues such as amplitude and phase defect printability, pattern repair techniques, contamination, inspection damage, and mask architecture. The AIT has a 6{sup o} illumination angle, and high-resolution exposure times are typically 20 seconds per image. The AIT operates semi-automatically capturing through-focus imaging series with step sizes as small as 0.1 {micro}m (0.5-0.8 {micro}m are typical), and a step resolution of 0.05 {micro}m. We believe it is the most advanced EUV mask inspection tool in operation today. In the AIT, an EUV image of the mask is projected by a zoneplate lens with high magnification (680-910x) onto a CCD camera. The CCD over-samples the image, providing equivalent pixel sizes down to 15 nm in mask coordinates-several image pixels per resolution element. The original AIT zoneplate specifications were designed to emulate the resolution of a 0.25-NA 4x stepper, and thorough benchmarking analysis of the aberrations, flare, contrast

  4. Evidence for NHE3-mediated Na transport in sheep and bovine forestomach.

    PubMed

    Rabbani, Imtiaz; Siegling-Vlitakis, Christiane; Noci, Bardhyl; Martens, Holger

    2011-08-01

    Na absorption across the cornified, multilayered, and squamous rumen epithelium is mediated by electrogenic amiloride-insensitive transport and by electroneutral Na transport. High concentrations of amiloride (>100 μM) inhibit Na transport, indicating Na(+)/H(+) exchange (NHE) activity. The underlying NHE isoform for transepithelial Na absorption was characterized by mucosal application of the specific inhibitor HOE642 for NHE1 and S3226 for NHE3 in Ussing chamber studies with isolated epithelia from bovine and sheep forestomach. S3226 (1 μM; NHE3 inhibitor) abolished electroneutral Na transport under control conditions and also the short-chain fatty acid-induced increase of Na transport via NHE. However, HOE642 (30 μM; NHE1 inhibitor) did not change Na transport rates. NHE3 was immunohistochemically localized in membranes of the upper layers toward the lumen. Expression of NHE1 and NHE3 has been previously demonstrated by RT-PCR, and earlier experiments with isolated rumen epithelial cells have shown the activity of both NHE1 and NHE3. Obviously, both isoforms are involved in the regulation of intracellular pH, pH(i). However, transepithelial Na transport is only mediated by apical uptake via NHE3 in connection with extrusion of Na by the basolaterally located Na-K-ATPase. The missing involvement of NHE1 in transepithelial Na transport suggests that the proposed "job sharing" in epithelia between these two isoforms probably also applies to forestomach epithelia: NHE3 for transepithelial transport and NHE1 for, among others, pH(i) and volume regulation. PMID:21613579

  5. Synergistic alpha-1 and alpha-2 adrenergic stimulation of rat proximal nephron Na+/H+ exchange

    SciTech Connect

    Gesek, F.A.; Cragoe, E.J. Jr.; Strandhoy, J.W.

    1989-06-01

    Both alpha-1 and alpha-2 adrenoceptors have been localized to the renal cortex, with the majority of binding sites on the proximal tubule. Because the major regulator of Na+ uptake into the proximal tubule is the Na+/H+ exchanger, and because alpha-1 and alpha-2 adrenoceptors stimulate it in other tissues, we tested the hypothesis that both alpha adrenoceptor subtypes can increase Na+ uptake into the proximal nephron by stimulating the Na+/H+ antiporter. Enhancement of Na+ transport by agonists was studied in isolated rat proximal tubules by determining the uptake of 22Na that was suppressible by the Na+/H+ inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA). The phorbol ester, phorbol-12-myristate-13-acetate, (0.1 microM), directly stimulated the antiporter through protein kinase C and increased EIPA-suppressible 22Na uptake 250% above control. The alpha-1 adrenoceptor agonists, cirazoline and phenylephrine, in addition to the mixed agonist, norepinephrine, maximally stimulated uptake by 226 to 232% at 1 microM concentrations. alpha-2 agonists produced a range of maximal stimulations at 1 microM from 65% with guanabenz to 251% with B-HT 933. Increases in 22Na uptake by agonists were inhibited by selective adrenergic antagonists and by EIPA. The drugs did not change the EIPA-resistant component of 22Na uptake. Inasmuch as the adrenoceptor subtypes likely stimulated Na+/H+ exchange by differing intracellular pathways impinging upon common transport steps, we examined whether simultaneous stimulation of both pathways was additive. Submaximal concentrations (5 nM each) of alpha-1 and alpha-2 adrenoceptor agonists in combination synergistically enhanced 22Na uptake to a level similar to 1 microM concentrations of adrenoceptor agonists alone or in combination.

  6. First Steps Towards Dissolution of NaSO4- by Water

    SciTech Connect

    Wang, Xue B.; Woo, Hin-koon; Jagoda-Cwiklik, Barbra; Jungwirth, Pavel; Wang, Lai S.

    2006-10-07

    NaSO4-(H2O)n (n = 0–4) clusters have been generated in the gas phase as model systems to simulate the first dissolution steps of sulfate salts in water; photoelectron spectroscopy and theoretical calculations indicate that the first three water molecules strongly interact with both Na+ and SO4 2-, forming a threewater solvation ring to pry apart the Na+SO4 2- contact ion pair.

  7. Long-term regulation of Na+,K+-ATPase in opossum kidney cells by ouabain.

    PubMed

    Silva, E; Soares-da-Silva, P

    2011-09-01

    Na(+),K(+)-ATPase, a basolateral transporter responsible for tubular reabsorption of Na(+) and for providing the driving force for vectorial transport of various solutes and ions, can also act as a signal transducer in response to the interaction with steroid hormones. At nanomolar concentrations ouabain binding to Na(+),K(+)-ATPase activates a signaling cascade that ultimately regulates several membrane transporters including Na(+),K(+)-ATPase. The present study evaluated the long-term effect of ouabain on Na(+),K(+)-ATPase activity (Na(+) transepithelial flux) and expression in opossum kidney (OK) cells with low (40) and high (80) number of passages in culture, which are known to overexpress Na(+),K(+)-ATPase (Silva et al., 2006, J Membr Biol 212, 163-175). Activation of a signal cascade was evaluated by quantification of ERK1/2 phosphorylation by Western blot. Na(+),K(+)-ATPase activity was determined by electrophysiological techniques and expression by Western blot. Incubation of cells with ouabain induced activation of ERK1/2. Long-term incubation with ouabain induced an increase in Na(+) transepithelial flux and Na(+),K(+)-ATPase expression only in OK cells with 80 passages in culture. This increase was prevented by incubation with inhibitors of MEK1/2 and PI-3K. In conclusion, ouabain-activated signaling cascade mediated by both MEK1/2 and PI-3K is responsible for long-term regulation of Na(+) transepithelial flux in epithelial renal cells. OK cell line with high number of passages is suggested to constitute a particular useful model for the understanding of ouabain-mediated regulation of Na(+) transport.

  8. Fibroblast growth factor homologous factor 13 regulates Na+ channels and conduction velocity in murine heart

    PubMed Central

    Wang, Chuan; Hennessey, Jessica A.; Kirkton, Robert D.; Wang, Chaojian; Graham, Victoria; Puranam, Ram S.; Rosenberg, Paul B.; Bursac, Nenad; Pitt, Geoffrey S.

    2012-01-01

    Rationale Fibroblast growth factor homologous factors (FHFs), a subfamily of fibroblast growth factors (FGFs) that are incapable of functioning as growth factors, are intracellular modulators of Na+ channels and have been linked to neurodegenerative diseases. Although certain FHFs have been found in embryonic heart, they have not been reported in adult heart, and they have not been shown to regulate endogenous cardiac Na+ channels nor participate in cardiac pathophysiology. Objective We tested whether FHFs regulate Na+ channels in murine heart. Methods and Results We demonstrated that isoforms of FGF13 are the predominant FHFs in adult mouse ventricular myocytes. FGF13 binds directly to, and co-localizes with the Na 1.5 Na+ V channel in the sarcolemma of adult mouse ventricular myocytes. Knockdown of FGF13 in adult mouse ventricular myocytes revealed a loss-of-function of NaV1.5: reduced Na+ current (INa) density, decreased Na+ channel availability, and slowed INa recovery from inactivation. Cell surface biotinylation experiments showed a ~45% reduction in NaV1.5 protein at the sarcolemma after FGF13 knockdown, whereas no changes in whole-cell NaV1.5 protein nor mRNA level were observed. Optical imaging in neonatal rat ventricular myocyte monolayers demonstrated slowed conduction velocity and a reduced maximum capture rate after FGF13 knockdown. Conclusion These findings show that FHFs are potent regulators of Na+ channels in adult ventricular myocytes and suggest that loss-of-function mutations in FHFs may underlie a similar set of cardiac arrhythmias and cardiomyopathies that result from NaV1.5 loss-of-function mutations. PMID:21817159

  9. Active and passive Na+ fluxes across the basolateral membrane of rabbit urinary bladder.

    PubMed

    Eaton, D C; Frace, A M; Silverthorn, S U

    1982-01-01

    The apical membrane of rabbit urinary bladder can be functionally removed by application of nystatin at high concentration if the mucosal surface of the tissue is bathed in a saline which mimics intracellular ion concentrations. Under these conditions, the tissue is as far as the movement of univalent ions no more than a sheet of basolateral membrane with some tight junctional membrane in parallel. In this manner the Na+ concentration at the inner surface of the basolateral membrane can be varied by altering the concentration in the mucosal bulk solution. When this was done both mucosal-to-serosal 22Na flux and net change in basolateral current were measured. The flux and the current could be further divided into the components of each that were either blocked by ouabain or insensitive to ouabain. Ouabain-insensitive mucosal-to-serosal Na+ flux was a linear function of mucosal Na+ concentration. Ouabain-sensitive Na+ flux and ouabain-sensitive, Na+-induced current both display a saturating relationship which cannot be accounted for by the presence of unstirred layers. If the interaction of Na+ with the basolateral transport process is assumed to involve the interaction of some number of Na+ ions, n, with a maximal flux, MMAX, then the data can be fit by assuming 3.2 equivalent sites for interaction and a value for MMAX of 287.8 pM cm-2 sec-1 with an intracellular Na concentration of 2.0 mM Na+ at half-maximal saturation. By comparing these values with the ouabain-sensitive, Na+-induced current, we calculate a Na+ to K+ coupling ratio of 1.40 +/- 0.07 for the transport process.

  10. Results from Boiling Temperature Measurements for Saturated Solutions in the Systems NaCl + KNO{sub 3} + H{sub 2}O, NaNO{sub 3} + KNO{sub 3} + H{sub 2}O, and NaCl + NaNO{sub 3} + KNO{sub 3} + H{sub 2}O

    SciTech Connect

    Rard, J A

    2004-10-04

    Boiling temperature measurements have been made for saturated ternary solutions of NaCl + KNO{sub 3} + H{sub 2}O and NaNO{sub 3} + KNO{sub 3} + H{sub 2}O over the full solute mole fraction range, along with the limiting binary solutions NaCl + H{sub 2}O, NaNO{sub 3} + H{sub 2}O, and KNO{sub 3} + H{sub 2}O. Boiling temperatures have also been measured for the quaternary NaCl + NaNO{sub 3} + KNO{sub 3} + H{sub 2}O mixtures with KNO{sub 3}:NaNO{sub 3} mole ratios of 1.01 and 1.19, which corresponding to the eutectic ratio and a near-eutectic ratio for the NaNO{sub 3} + KNO{sub 3} + H{sub 2}O subsystem. The maximum boiling temperature found for the NaCl + KNO{sub 3} + H{sub 2}O system is 134 C and for the NaNO{sub 3} + KNO{sub 3} + H{sub 2}O system is 160 C, but boiling temperatures as high as 196 C were measured the NaCl + NaNO{sub 3} + KNO{sub 3} + H{sub 2}O system. These mixture compositions correspond to the major mineral assemblages that are predicted to control the deliquescence relative humidity of salts found by leaching dust samples from the proposed nuclear repository at Yucca Mountain, Nevada.

  11. Membrane-integral pyrophosphatase subfamily capable of translocating both Na+ and H+.

    PubMed

    Luoto, Heidi H; Baykov, Alexander A; Lahti, Reijo; Malinen, Anssi M

    2013-01-22

    One of the strategies used by organisms to adapt to life under conditions of short energy supply is to use the by-product pyrophosphate to support cation gradients in membranes. Transport reactions are catalyzed by membrane-integral pyrophosphatases (PPases), which are classified into two homologous subfamilies: H(+)-transporting (found in prokaryotes, protists, and plants) and Na(+)-transporting (found in prokaryotes). Transport activities have been believed to require specific machinery for each ion, in accordance with the prevailing paradigm in membrane transport. However, experiments using a fluorescent pH probe and (22)Na(+) measurements in the current study revealed that five bacterial PPases expressed in Escherichia coli have the ability to simultaneously translocate H(+) and Na(+) into inverted membrane vesicles under physiological conditions. Consistent with data from phylogenetic analyses, our results support the existence of a third, dual-specificity bacterial Na(+),H(+)-PPase subfamily, which apparently evolved from Na(+)-PPases. Interestingly, genes for Na(+),H(+)-PPase have been found in the major microbes colonizing the human gastrointestinal tract. The Na(+),H(+)-PPases require Na(+) for hydrolytic and transport activities and are further activated by K(+). Based on ionophore effects, we conclude that the Na(+) and H(+) transport reactions are electrogenic and do not result from secondary antiport effects. Sequence comparisons further disclosed four Na(+),H(+)-PPase signature residues located outside the ion conductance channel identified earlier in PPases using X-ray crystallography. Our results collectively support the emerging paradigm that both Na(+) and H(+) can be transported via the same mechanism, with switching between Na(+) and H(+) specificities requiring only subtle changes in the transporter structure.

  12. Effects of Na on the electrical and structural properties of CuInSe2

    NASA Astrophysics Data System (ADS)

    Wei, Su-Huai; Zhang, S. B.; Zunger, Alex

    1999-05-01

    We found theoretically that Na has three effects on CuInSe2: (1) If available in stoichiometric quantities, Na will replace Cu, forming a more stable NaInSe2 compound having a larger band gap (higher open-circuit voltage) and a (112)tetra morphology. The ensuing alloy NaxCu1-xInSe2 has, however, a positive mixing enthalpy, so NaInSe2 will phase separate, forming precipitates. (2) When available in small quantities, Na will form defect on Cu site and In site. Na on Cu site does not create electric levels in the band gap, while Na on In site creates acceptor levels that are shallower than CuIn. The formation energy of Na(InCu) is very exothermic, therefore, the major effect of Na is the elimination of the InCu defects and the resulting increase of the effective hole densities. The quenching of InCu as well as VCu by Na reduces the stability of the (2VCu-+InCu2+), thus suppressing the formation of the "Ordered Defect Compounds." (3) Na on the surface of CuInSe2 is known to catalyze the dissociation of O2 into atomic oxygen that substitutes Se vacancy (shallow donors), converting them into OSe. We find, however, that OSe is an (isovalent) deep rather than shallow acceptor. We also find that having removed the donors, O atoms in CuInSe2 form Cu2O and In2O3 compounds, and phase separate, forming precipitates at the surfaces and grain boundaries. Our results are compared with previous models and provide new insights into the defect physics of Na in CIS.

  13. Effect of salt stress on growth, Na+ accumulation and proline metabolism in potato (Solanum tuberosum) cultivars.

    PubMed

    Jaarsma, Rinse; de Vries, Rozemarijn S M; de Boer, Albertus H

    2013-01-01

    Potato (Solanum tuberosum) is a major crop world-wide and the productivity of currently used cultivars is strongly reduced at high soil salt levels. We compared the response of six potato cultivars to increased root NaCl concentrations. Cuttings were grown hydroponically and treated with 0 mM, 60 mM and 180 mM NaCl for one week. Growth reduction on salt was strongest for the cultivars Mozart and Mona Lisa with a severe senescence response at 180 mM NaCl and Mozart barely survived the treatment. The cultivars Desiree and Russett Burbank were more tolerant showing no senescence after salt treatment. A clear difference in Na(+) homeostasis was observed between sensitive and tolerant cultivars. The salt sensitive cultivar Mozart combined low Na(+) levels in root and stem with the highest leaf Na(+) concentration of all cultivars, resulting in a high Na(+) shoot distribution index (SDI) for Mozart as compared to Desiree. Overall, a positive correlation between salt tolerance and stem Na(+) accumulation was found and the SDI for Na(+) points to a role of stem Na(+) accumulation in tolerance. In stem tissue, Mozart accumulated more H2O2 and less proline compared to the tolerant cultivars. Analysis of the expression of proline biosynthesis genes in Mozart and Desiree showed a clear reduction in proline dehydrogenase (PDH) expression in both cultivars and an increase in pyrroline-5-carboxylate synthetase 1 (P5CS1) gene expression in Desiree, but not in Mozart. Taken together, current day commercial cultivars show promising differences in salt tolerance and the results suggest that mechanisms of tolerance reside in the capacity of Na(+) accumulation in stem tissue, resulting in reduced Na(+) transport to the leaves.

  14. Di- and tricobalt Dawson sandwich complexes: synthesis, spectroscopic characterization, and electrochemical behavior of Na(18)[(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)] and Na(17)[(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)].

    PubMed

    Ruhlmann, Laurent; Canny, Jacqueline; Contant, Roland; Thouvenot, René

    2002-07-29

    The reaction of the trivacant Dawson anion alpha-[P(2)W(15)O(56)](12-) and the divalent cations Co(2+) is known to form the tetracobalt sandwich complex [Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-) (Co(4)P(4)W(30)). Two new complexes, with different Co/P(2)W(15) stoichiometry, [(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)](18-) (Na(2)Co(2)P(4)W(30)) and [(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)](17-) (NaCo(3)P(4)W(30)), have been synthesized as aqueous-soluble sodium salts, by a s