Properties Of Na Research Articles

Influence of Anticholinesterase Drugs on Activity and Properties of Na+,K+-ATPase in Rat Erythrocytes under Stress Caused by Intense Physical Exercise.

We studied the effect of intramuscular injection of physostigmine and neostigmine on Na+,K+-ATPase activity in erythrocytes of rats subjected to intense physical exercise. Both anticholinesterase drugs had a significant effect on the development of the stress response, which was expressed in a decrease in the manifestation of its individual components such as the concentration of ascorbic acid in the adrenal glands, stress-related erythrocyte polycythemia, and LPO indicators. Anticholinesterase drugs reverse the stress-induced decrease in Na+,K+-ATPase activity, as well as changes in its magnesium-dependent properties. There were no changes in the activity of the studied enzyme in the erythrocyte ghosts. We associate the observed differences with the correction of the functions of the cholinergic components of the hypothalamic-pituitary-adrenal axis leading to the development of a hypoergic type stress reaction.

Study on synthesis and properties of Na+–La3+ co-doped γ-Ce2S3 pigment by low-temperature self-propagating combustion method

Study on synthesis and properties of Na+–La3+ co-doped γ-Ce2S3 pigment by low-temperature self-propagating combustion method

Enhancement of photoluminescence properties in Na+ doped K2BaPO4F:Sm3+ phosphors

In this paper, Sm3+-activated K2BaPO4F red phosphors were prepared by a traditional solid-state reaction method. The crystal structure and emission enhancement mechanism of the materials were systematically investigated. The photoluminescence intensity, chromaticity, lifetime, and fluorescence thermal stability were evaluated in detail. The emission intensity and quantum efficiency were significantly improved by the introduction of Na + ions. The lattice parameters of the K2BaPO4F, K2Ba0.975PO4F:0.025Sm3+, and Na-doped K2Ba0.975PO4F:0.025Sm3+ phosphors were investigated through the Rietveld refinement method. With the occupation of K+ sites by Na+ ions, the reduced volume of the unit cell increased the quantum efficiency of Sm3+ ions about 2.5 times. The present work demonstrates that the modified K2-2xNa2xBa0.975PO4F:0.025Sm3+ orange-red phosphors are expected to be used in white light-emitting diodes (w-LEDs).

Investigation into the effect on the property of Na<sub>2</sub>WO<sub>4</sub> ceramic prepared by the further modified solid-state reaction method

Investigation into the effect on the property of Na<sub>2</sub>WO<sub>4</sub> ceramic prepared by the further modified solid-state reaction method

Enhanced Relaxor Behavior and Energy‐Storage Properties in Na0.5Bi0.5TiO3‐Based Ceramics by Doping the Complex Ions (Al0.5Nb0.5)4+

Herein, (Na0.5Bi0.5)0.94Ba0.06Ti1‐x(Al0.5Nb0.5)xO3 (NBBT‐xAN) ceramics are fabricated through a solid reaction method. X‐ray diffraction reveals the structure of NBBT‐xAN ceramics transforms from coexistence of rhombohedral and tetragonal structures to a pseudocubic structure with increasing AN content. Raman spectroscopy indicates the long‐range ferroelectric order of NBBT ceramics is broken by AN and the polar nanoregions (PNRs) with weak polarization are formed. The relaxor behavior of NBBT ceramics is enhanced by the enhanced random electric fields (REFs) through the heterovalent cations Al3+/Nb5+. Therefore, a slim and pinched P–E loop is obtained for NBBT ceramics by doping AN and the energy‐storage properties (ESPs) can be improved dramatically under a low electric field. The maximum recoverable energy density (Wrec) of 1.2 J cm−3 is obtained at x = 0.04 under a low electric field of 100 kV cm−1. However, a relatively high Wrec of 1.0 J cm−3 and efficiency (η) of 77% are simultaneously obtained at x = 0.05 under the same electric field strength. Moreover, NBBT‐0.05AN ceramics also exhibit excellent temperature (30–180 °C), fatigue (104) and frequency (1–40 Hz) stabilities. Most important, the study provides a strategy to design high energy‐storage capacitors under a low electric field.

Influence of Gd3+ doping concentration on the properties of Na(Y,Gd)F4:Yb3+, Tm3+ upconverting nanoparticles and their long-term aging behavior

We present a systematic study on the properties of Na(Y,Gd)F4-based upconverting nanoparticles (UCNP) doped with 18% Yb3+, 2% Tm3+, and the influence of Gd3+ (10–50 mol% Gd3+). UCNP were synthesized via the solvothermal method and had a range of diameters within 13 and 50 nm. Structural and photophysical changes were monitored for the UCNP samples after a 24-month incubation period in dry phase and further redispersion. Structural characterization was performed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as dynamic light scattering (DLS), and the upconversion luminescence (UCL) studies were executed at various temperatures (from 4 to 295 K) using time-resolved and steady-state spectroscopy. An increase in the hexagonal lattice phase with the increase of Gd3+ content was found, although the cubic phase was prevalent in most samples. The Tm3+-luminescence intensity as well as the Tm3+-luminescence decay times peaked at the Gd3+ concentration of 30 mol%. Although the general upconverting luminescence properties of the nanoparticles were preserved, the 24-month incubation period lead to irreversible agglomeration of the UCNP and changes in luminescence band ratios and lifetimes.

Synthetic control of structure and conduction properties in Na–Y–Zr–Cl solid electrolytes

In this study, the relationship between structure, cation disorder and Na-ion conduction properties is elucidated in a series of Na3−xY1−xZrxCl6 solid electrolytes.

Dielectric, ferroelectric and optical properties of Na and Nb co-doped (Bi0.5Na0.5)0.94Ba0.06TiO3

[(Bi0.5Na0.5)0.94Ba0.06]1-xNaTi1-xNbO3 (x = 0.5 and 0.10) ceramics were prepared via conventional solid-state sintering route. X-ray diffraction analysis of the samples exhibited the formation of the cubic structure. Similar structure was observed from the Raman spectra of the samples. The optical band gap of the samples slightly decreased from 3.08 to 3.06 eV with increasing level of Na+ and Nb5+. The addition of Na+ and Nb5+ shifted Tm towards room temperature (RT). The sample x = 0.05 had a stable relative permittivity ɛr(mid) = 3914 across the temperature range 79-350 ℃ and tanδ < 0.025 (104-279 ℃). The energy density of sample with x = 0.05 was 0.4 J/cm3 which decreased to 0.32 J/cm3 at an applied electric field of 50 kV/cm with further substitution of Na+ and Nb5+ (i.e., x = 0.10).

Effect of Detergents on Activity and Magnesium-Dependent Properties of Different Isoforms of Na+,K+-ATPase in the Crude Membrane Fraction of Rat Cerebral Cortex.

We studied the effect of various detergents (Tween-20, Triton X-100, and sodium deoxycholate) on activity and magnesium-dependent properties of Na+,K+-ATPase of the crude membrane fraction of rat cerebral cortex. All studied detergents significantly increased activity of the studied enzyme in a concentration-dependent manner. Sodium deoxycholate provided significantly higher values Na+,K+-ATPase activity (by ≈50%) than Triton X-100 and Tween-20. In the presence of Triton X-100, a changed pattern of the dependence of enzyme activity on the concentration of magnesium ions in the incubation solution was noted. Separate measurement of activities of Na+,K+-ATPase isoforms made it possible to assume that changes in magnesium-dependent properties are due to the predominant effect of Triton X-100 on ouabain-sensitive α2- and α3-isoforms.

Functional correlation of ATP1A2 mutations with phenotypic spectrum: from pure hemiplegic migraine to its variant forms

BackgroundMutations in ATP1A2, the gene encoding the α2 subunit of Na+/K+-ATPase, are the main cause of familial hemiplegic migraine type 2 (FHM2). The clinical presentation of FHM2 with mutations in the same gene varies from pure FHM to severe forms with epilepsy and intellectual disability, but the correlation of these symptoms with different ATP1A2 mutations is still unclear.MethodsTen ATP1A2 missense mutations were selected according to different phenotypes of FHM patients. They caused pure FHM (FHM: R65W, R202Q, R593W, G762S), FHM with epilepsy (FHME: R548C, E825K, R938P), or FHM with epilepsy and intellectual disability (FHMEI: T378N, G615R, D718N). After ouabain resistance and fluorescence modification, plasmids carrying those mutations were transiently transfected into HEK293T and HeLa cells. The biochemical functions were studied including cell survival assays, membrane protein extraction, western blotting, and Na+/K+-ATPase activity tests. The electrophysiological functions of G762S, R938P, and G615R mutations were investigated in HEK293T cells using whole-cell patch-clamp. Homology modeling was performed to determine the locational distribution of ATP1A2 mutations.ResultsCompared with wild-type pumps, all mutations showed a similar level of protein expression and decreased cell viability in the presence of 1 µM ouabain, and there was no significant difference among the mutant groups. The changes in Na+/K+-ATPase activity were correlated with the severity of FHM phenotypes. In the presence of 100 µM ouabain, the Na+/K+-ATPase activity was FHM > FHME > FHMEI. The ouabain-sensitive Na+/K+-ATPase activity of each mutant was significantly lower than that of the wild-type protein, and there was no significant difference among all mutant groups. Whole-cell voltage-clamp recordings in HEK293T cells showed that the ouabain-sensitive pump currents of G615R were significantly reduced, while those of G762S and R938P were comparable to those of the wild-type strain.ConclusionsATP1A2 mutations cause phenotypes ranging from pure FHM to FHM with epilepsy and intellectual disability due to varying degrees of deficits in biochemical and electrophysiological properties of Na+/K+-ATPase. Mutations associated with intellectual disability presented with severe impairment of Na+/K+-ATPase. Whether epilepsy is accompanied, or the type of epilepsy did not seem to affect the degree of impairment of pump function.

Culture conditions effect properties of the Na+/K+-ATPase pump current in hiPSC cardiomyocytes

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): BMBF Background Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC) provide an opportunity to study human cardiac physiology and pathophysiology or to use for cardiac repair as well as for cardiovascular drug testing. Suitability for these purposes requires generating hiPSC cardiomyocytes that share typical electrophysiological properties of adult human cardiomyocytes. In the human heart the Na+/K+-ATPase pump current plays a major role in the regulation of contractile force and electrical stability. So far there are no data about Na+/K+-ATPase pump current function in hiPSC cardiomyocytes available. Purpose We compared the properties of Na+/K+-ATPase pump current in hiPSC cardiomyocytes from conventional monolayers (ML) culture to three-dimensional engineered heart tissue (EHT). Methods HiPSC cardiomyocytes differentiated from in-house control hiPSC cell line C25 were dissociated from ML and EHT culture. Na+/K+-ATPase pump current was recorded by whole-cell patch clamp technique at 37°C. The holding potential was -40 mV to inactivate sodium current. Current was measured in the absence of K+ and after adding 5.4 mM potassium chloride (KCL). Na+/K+-ATPase pump current was defined as the ouabain (10 µM) sensitive current. Voltage-dependency of Na+/K+-ATPase pump was determined using rectangular voltage pulses (increasing from -120 mV to +60 mV). Results Outwardly directed Na+/K+-ATPase pump could be recorded at -40 mV when KCL was added to the bath solution (5.4 mM). Currents were larger in EHT than in ML (0.8 ± 0.08 pA/pF n = 16 ML vs. 1.29 ± 0.13 pA/pF n = 28 EHT; p < 0.05). The K+-induced outward current was abolished by ouabain. The K+- and ouabain-sensitive current densities were similar in size (0.84 ± 0.11 pA/pF n = 16 ML vs. 1.12 ± 0.11 pA/pF n = 28 EHT for ouabain), indicating the measured K+-induced current was Na+/K+-ATPase pump current. Increasing extracellular K+-concentration in a stepwise manner (0,25 mM, 0,5 mM, 1 mM, 2 mM, 5,4 mM and 10 mM) showed a concentration-dependent relationship to Na+/K+-ATPase pump current with throughout higher current densities in EHT compared to ML (sensitivity to K+ not different). Na+/K+-ATPase pump current showed expected voltage-dependency with +0.23 ± 0.13 pA/pF at -120 mV and +0.89 ± 0.16 pA/pF at +60 mV (n= 18) in ML and with +0.71 ± 0.17 pA/pF at -120 mV and +1.2 ± 0.2 pA/pF at +60 mV (n= 24) in EHT. Conclusion HiPSC cardiomyocytes possess Na+/K+-ATPase pump current. Current density is in the range of human cardiomyocytes in EHT but substantially smaller in ML. 3D culturing may be needed to develop the physiological properties of Na+/K+-ATPase pump current.

Effect of MnO2 Dopant on Properties of Na+-β/β"-Al2O3 Solid Electrolyte Prepared by a Synthesizing-cum-sintering Process

In order to simplify the complexity of the conventional solid-state reaction process, Na+-β/β″-Al2O3 as a fast Na+-ionic conductive solid electrolyte was fabricated using a synthesizing-cum-sintering process combined with the double-zeta method, which is able to distribute a small amount of Li2O more homogeneously in the Na2O-Al2O3-Li2O system. Additionally, in order to enhance the ionic conductivity, MnO2 was used as a dopant to increase the Na+-ion concentration on the conduction plane in the Na+-β/β″-Al2O3 crystal structure. The relative sintered density increased with the synthesis temperature, ultimately reaching 99.7 % after synthesis at 1400 °C. The phase formation showed an overall β″-phase fraction over 90 %. The addition of MnO2 had a positive effect on the phase formation, but a negative influence on the relative density resulting from the grain growth promotion effect. The highest ionic conductivity was observed at 1.74 × 10-1 S/cm (350 °C) for the sample sintered at 1600 °C with 0.5 wt.% MnO2.

Properties of Na 0.5Bi0.5TiO3 and Na0.5Bi0.5 TiO3-based single crystals

Most studies of ferroelectric materials were focused on polycrystalline ceramics. However, it is difficult to improve their properties significantly (particularly piezoelectric one) due to grain/grain boundaries, compositional homogeneity, isotropic characteristics, and structural defects. It is commonly accepted that single crystals often have better piezoelectric behavior and less structural defects than ceramics. In this paper, we provide the processing technology and properties of lead-free Na0.5Bi0.5TiO3 and Na0.5Bi0.5TiO 3-based single crystals. #FERROELECTRICS #NBT_SINGLE_CRYSTALS #FLUX_METHOD #CZOCHRALSKI_METHOD #DIELECTRIC_PROPERTIES

First-principles study of the structural and electrochemical properties of NaxTi2O4 (0 ≤x≤ 1) with tunnel structure for anode applications in alkali-ion batteries.

Due to their low cost and easy synthesis method, several kinds of sodium titanates have been explored as anode materials for sodium ion batteries (SIBs). However, some of them have not yet been considered as electrode materials for SIBs, and here we have carried out a first-principles study on NaxTi2O4 compounds with two different tunnel structures, denoted as single and double phases, to demonstrate their structural and electrochemical properties upon Na or Li insertion. Our calculation results reveal that these compounds exhibit structural stability during sodiation/desodiation and a moderate electrode voltage of ∼0.82 V vs. Na+/Na with a specific capacity of ∼150 mA h g-1. In particular, the activation energy of Na+ ion migration in the double phase is estimated to be as low as 0.28 eV, which is the lowest value among the SIB electrodes developed so far, and this can be attributed to the wide tunnel structure. In addition, we verify their potentiality for use as anode materials in lithium ion batteries (LIBs) by exploring their properties upon Li insertion. Since these compounds are predicted to be promising anode materials for SIBs or LIBs by our calculations, we believe that our findings will promote further experimental studies.

Calculation of thermic and electric properties and valence electron structure for metallic electrodes of Na||Sb-Pb-Sn liquid metal battery

<sec>The valence electron structures and thermal and electric properties of Na||Sb-Pb-Sn liquid metal battery are systematically studies with solid and molecular empirical electron theory (EET). The theoretical studies show that the thermal and electric properties are strongly related to the valence electron structure of electrode. The cathodic alloys Na<sub>1–</sub><sub><i>x</i></sub>IA<i><sub>x </sub></i>(IA = K, Rb, Cs) are designed by doping IA group alkali metals (K, Rb, Cs) into Na electrode since the melting points of IA group metals (K, Rb, Cs) are all lower than that of sodium. The theoretical bond lengths and cohesive energy of cathodic alloys Na<sub>1–</sub><sub><i>x</i></sub>IA<i><sub>x</sub></i> match the experimental ones well. The theoretical studies show the decreasing tendency of melting point, cohesive energy and electric potential with increasing doping content <i>x</i> in Na<sub>1–</sub><sub><i>x</i></sub>IA<i><sub>x</sub></i> alloys, which is due to the modulation of valence electron structure of IA group dopants. According to the analyses of valence structures, the number of lattice electrons decreases with the increasing of the doping content <i>x</i> for the cathodic alloy and causes the melting point, electric potential and cohesive energy to decline. It reveals that the IA group dopant modulates the valence electron structure of cathodic alloy, and induces the electron transformation from lattice electron to covalent electron in s orbital. </sec><sec>The anode products such as NaSb<sub>3</sub>, NaSn, Na<sub>15</sub>Sn<sub>4</sub> and NaPb are formed by transporting Na ions into the anode alloy Sb-Sn-Pb. The calculated bond-lengths and melting points fit the observed ones well for these anode products. Owing to their complex structures with various atomic occupations in unit cell, the thermal property or electric property is not only relative to lattice electron, but also depends on the covalent electron. The sublattice plays an important role in the forming of the four anode products. The lattice electrons are supplied by Na at 4<i>f</i> sites in Na<sub>3</sub>Sb, Na at 16<i>e</i> and Sn at 32<i>g</i> sites in NaSn, Sn at 16<i>c</i> and Na at 48<i>e</i> sites in Na<sub>15</sub>Sn<sub>4</sub>, and Na at 16<i>f</i> and Pb at 32<i>g</i> sites in NaPb, respectively. </sec><sec>The open-gate voltage is closely related to the lattice electrons and inversely proportional to the average number of lattice electrons per atom. The open-gate voltage of NaSb<sub>3</sub> is the largest among the anode products, however, its averaged number of lattice electron per atom is the least. Since the lattice electron number of NaSn is the largest among the anode products, the open-gate voltage of NaSn is the least. It implies that the lattice electron plays a very important role in Na||Sb-Pb-Sn liquid metal battery, which can modulate the valence electron structures and thermal and electric properties. </sec>

Investigation of Ti‐substitution effects on structural and electrochemical properties of Na 0. 67 Mn 0 . 5 Fe 0 . 5 O 2 battery cells

Investigation of Ti‐substitution effects on structural and electrochemical properties of Na _0. <scp> ₆₇ Mn ₀ </scp> _. <scp> ₅ Fe ₀ </scp> _. <scp> ₅ O ₂ battery </scp> cells

Structure of aqueous sodium acetate solutions by X-Ray scattering and density functional theory

Abstract The structure of aq. sodium acetate solution (CH3COONa, NaOAc) was studied by X-ray scattering and density function theory (DFT). For the first hydrated layer of Na+, coordination number (CN) between Na+ and O(W, I) decreases from 5.02 ± 0.85 at 0.976 mol/L to 3.62 ± 1.21 at 4.453 mol/L. The hydration of carbonyl oxygen (OC) and hydroxyl oxygen (OOC) of CH3COO− were investigated separately and the OC shows a stronger hydration bonds comparing with OOC. With concentrations increasing, the hydration shell structures of CH3COO− are not affected by the presence of large number of ions, each CH3COO− group binds about 6.23 ± 2.01 to 7.35 ± 1.73 water molecules, which indicates a relatively strong interaction between CH3COO− and water molecules. The larger uncertainty of the CN of Na+ and OC(OOC) reflects the relative looseness of Na-OC and Na-OOC ion pairs in aq. NaOAc solutions, even at the highest concentration (4.453 mol/L), suggesting the lack of contact ion pair (CIP) formation. In aq. NaOAc solutions, the so called “structure breaking” property of Na+ and CH3COO− become effective only for the second hydration sphere of bulk water. The DFT calculations of CH3COONa (H2O)n=5–7 clusters suggest that the solvent-shared ion pair (SIP) structures appear at n = 6 and become dominant at n = 7, which is well consistent with the result from X-ray scattering.

Combining effects of TiO6 octahedron rotations and random electric fields on structural and properties in Na0.5Bi0.5TiO3

AbstractThe structural and dielectric properties of Na0.5Bi0.5TiO3 (NBT) ceramics and crystals have been investigated and are compared to that of Pb(Zr0.55Ti0.45)O3 (PZT55/45) and Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMNT 72/28) ceramics. X‐ray diffraction (XRD) profiles for (100), (110), (111), (200), (220), and (222) (referred to cubic structure) reveal that the monoclinic structure with Cc space group exists both in the NBT single crystal and ceramics. The diffraction profile obtained with high resolution laboratory XRD for the NBT single crystal can be well described, using Cc model instead of R3c model. The dielectric constant of NBT below Thump shows some similarity to that of PZT45/55 ceramics below 50°C in which oxygen octahedron rotations cause the frequency dispersion of the dielectric constant. The temperature‐dependent dielectric constant for NBT can be deconvolved into two independent processes. The lower temperature process shows a typical relaxor characteristic and follows the Vogel‐Fulcher relationship. The other process at higher temperature shows less frequency‐dependent behavior. Comparing the dielectric constant of NBT with that of PZT55/45 and PMNT72/28 reveals that both oxygen octahedral rotations and random electric fields play an important role in the frequency dispersion of the dielectric constant for NBT relaxor feroelectric.

Revealing the sodium storage of surface C[dbnd]O structure in high performance Na-ion battery

Although sodium-ion batteries (SIBs) have gotten a growing concern for energy storage system because of the natural sufficient of sodium, their progress is hindered due to destitute insertion/extraction property of Na+ in electrodes. This work reports a clear study of an ultralong cycle stability and high specific capacity in biomass derived carbon (BDC). The Na+ storage mechanism is rely on the reaction between surface CO structure and Na+ (there is no electrode structure change during this reaction). This BDC with more surface CO structure is useful for the Na+ storage, When evaluated as an anode for SIBs, it displays a good rate capacity (514 mA h·g−1 at 0.05 A·g−1, 212 mA h·g−1 at 10 A·g−1) and a high reversible capacity (315 mA h·g−1 at 1 A·g−1 after 900 cycles).

The Influences of Sio2 on the Sintering Behavior and the Properties of Na+- Β/Β"-Al2O3 Solid Electrolyte

SiO2-doped Na+-β/β″-Al2O3 was synthesized via a solid-state reaction, and the relationship between the SiO2 content and properties of Na+-β/β″-Al2O3 was investigated. Respective specimens were doped with 0 – 5 wt.% SiO2 as a liquid phase sintering promotor and sintered. The specimens were characterized by XRD, SEM, densimeter and impedance analyzer. In the sintered samples, the phase fraction of β″-Al2O3 decreased as the SiO2 content increased, whereas the relative sintered density was enhanced with the inclusion of less than 0.7 wt.% SiO2. The relative sintered density of Na+- β/β″-Al2O3 sintered specimen with 0.7 wt.% SiO2 doping reached 99.2 % of the theoretical density and the sintered density decreased when the amount of SiO2 was larger than 1 wt.% result from excessive liquid-phase formation during sintering. Similarly, the ionic conductivity of SiO2-doped Na+-β/β″-Al2O3 was enhanced by doping with a small amount of SiO2, whereas the addition of more than 1 wt.% SiO2 negatively affected the ionic conductivity of Na+-β/β″-Al2O3 due to a decrease in the sintered density and unfavorable phase relationship. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.14246