Increase In Sodium Ion Concentration Research Articles

Optimizing conductivity in Na-V-Te-O glass through controlled heat treatment

Semiconducting Na2O-V2O5-TeO2 glasses with various Na2O contents were melted and subjected to controlled heating to improve conductivity. Topography analysis were performed using confocal microscopy and scanning electron microscopy on both as-quenched and heat-treated samples. X-ray diffraction confirmed the amorphous nature of the samples post-melting, with subsequent heating resulting in the formation of nanocrystallites primarily composed of vanadium ions. The Na2O addition caused progressive depolymerization of the tellurite-vanadate network, as evidenced by IR spectroscopy, although heating exhibited an opposing effect, particularly noticeable in vanadate-related bands. Thermal properties revealing a decrease in the glass transition temperature, crystallization process, and thermal stability with increasing sodium ion concentration. Electrical properties were investigated using impedance spectroscopy, which enabled determination of DC conductivity values, polaron jump energies, and disturbance energies in the samples. The electrical conductivity mechanisms were described as mixed ionic-polaronic, with polaron hopping predominating. Heat treatment significantly enhanced polaron conductivity and altered its nature.

The Spectral Reflectance Response of ‘Riviera’ Common Bermudagrass to Increasing Saline Irrigation Concentrations

The availability of freshwater is a growing concern throughout the world as it is an increasingly valuable and limited resource. Alternative water resources such as recycled water low in quality and high in salinity are now frequently used to irrigate turfgrass. However, irrigating with highly saline water can affect the growth, performance, appearance, and quality of turfgrass. Bermudagrass (Cynodon sp.) is the most commonly used turfgrass throughout the southern United States. In this study, the spectral reflectance and visual response of ‘Riviera’ common bermudagrass (Cynodon dactylon) were evaluated by consecutively irrigating with 12 salinity concentrations (4–48 dS·m−1) in increments of 4 dS·m−1 via manual overhead irrigation for 30 days. The experiment was replicated in time in a controlled environment with four replications for each salinity treatment and control. ‘Riviera’ maintained a leaf firing (LF) value above 5 (rated on a scale from 1 to 9) when irrigated with 28 dS·m−1 for 30 days. Also, the LF value did not fall below 2 when irrigated with a salinity concentration of 48 dS·m−1 for 30 days, suggesting high salinity tolerance of ‘Riviera’. However, in this study, the normalized difference vegetation index (NDVI) had a lower ability to detect the increase in salinity stress due to the limited area measured by the NDVI measuring device used. An increase in sodium ion concentration was observed in the shoot with increasing salinity concentrations. The NDVI was highly correlated (r = 0.93) to LF, indicating the usefulness of NDVI as a tool to measure the magnitude of salinity stress. The multiple linear regression analysis revealed that the data showed a linear response to salinity stress with LF (r2 = 0.86) and NDVI (r2 = 0.76) decreasing linearly as the salinity concentration and days of treatment increased. This study provides an accurate depiction of the spectral and visual responses of ‘Riviera’ when exposed to multiple salinity concentrations with narrow increments.

Effects of gelling bath on the physical properties of alginate gel beads and the biological characteristics of entrapped HepG2 cells.

Optimizing alginate gel beads is necessary to support the survival, proliferation, and function of entrapped hepatocytes. In this study, gelling bath was modified by decreasing calcium ion concentration and increasing sodium ion concentration. Alginate gel beads (using 36% G sodium alginate) prepared in the modified gelling bath had more homogeneous structure and better mass transfer properties compared with the traditional gelling bath that contains only calcium ions. Moreover, alginate gel beads generated in the modified gelling bath could significantly promote the HepG2 cell proliferation and the growth of cell spheroids, and maintain the albumin secretion ability similar to alginate gel beads prepared in the traditional gelling bath with only calcium ions. The mass transfer properties and cell proliferation were similar in ALG beads with different M/G ratio (36% G and 55% G) generated in the modified gelling bath, whereas they were significantly increased compared with alginate gel beads (55% G) in traditional gelling bath. These results indicated that adjusting the gelling bath was a simple and convenient method to enhance the mass transfer properties of alginate gel beads for 3D hepatocyte culture, which might provide more hepatocytes for the bioartificial liver support system.

Fluorescence- and Radiolabeling of [Lys4,Nle17,30]hPP Yields Molecular Tools for the NPY Y4 Receptor.

The neuropeptide Y (NPY) Y4 receptor (Y4R) is involved in energy homeostasis and considered a potential drug target for the treatment of obesity. Only a few molecular tools, i.e., radiolabeled and fluorescent ligands, for the investigation of the Y4R were reported. Previously, [Lys4]hPP proved to be an appropriate full-length PP analog to prepare a fluorescent ligand by derivatization at the ε-amino group. To preclude oxidation upon long-term storage, we replaced the two methionine residues in [Lys4]hPP by norleucine and prepared the corresponding [3H]propionylated ([3H]12) and cyanine labeled (13) peptides, which were characterized and compared with a set of reference compounds in binding (Y1, Y2, Y4, and Y5 receptors) and functional (luciferase gene reporter, beta-arrestin-1,2) Y4R assays. Both molecular probes proved to be useful in radiochemical and flow cytometric saturation and competition Y4R binding experiments. Most strikingly, there was a different influence of the composition of buffer on equilibrium binding and kinetics: [3H]12 affinity (Kd in Na+-free buffer: 1.1 nM) clearly decreased with increasing sodium ion concentration, whereas dissociation and Y4R-mediated internalization of 13 (Kd in Na+-free buffer: 10.8 nM) were strongly affected by the osmolarity of the buffer as demonstrated by confocal microscopy. Displacement of [3H]12 and 13 revealed a tendency to higher apparent affinities for a set of reference peptides in hypotonic (Na+-free) compared to isotonic buffers. The differences were negligible in the case of hPP but up to 270-fold in the case of GW1229 (GR231118). By contrast, no relevant influence of Na+ on Y5R affinity became obvious, when the radioligands [H]12 and [3H]propionyl-pNPY were investigated in saturation binding and competition binding.

BDST modelling of sodium ion exchange column behaviour with strong acid cation resin in relation to coal seam water treatment

Reverse osmosis is the dominant technology utilized for desalination of saline water produced during the extraction of coal seam gas. Alternatively, ion exchange is of interest due to potential cost advantages. However, there is limited information regarding the column performance of strong acid cation resin for removal of sodium ions from both model and actual coal seam water samples. In particular, the impact of bed depth, flow rate, and regeneration was not clear. Consequently, this study applied Bed Depth Service Time (BDST) models to reveal that increasing sodium ion concentration and flow rates diminished the time required for breakthrough to occur. The loading of sodium ions on fresh resin was calculated to be ca. 71.1gNa/kg resin. Difficulties in regeneration of the resin using hydrochloric acid solutions were discovered, with 86% recovery of exchange sites observed. The maximum concentration of sodium ions in the regenerant brine was found to be 47,400mg/L under the conditions employed. The volume of regenerant waste formed was 6.2% of the total volume of water treated. A coal seam water sample was found to load the resin with only 53.5g Na/kg resin, which was consistent with not only the co-presence of more favoured ions such as calcium, magnesium, barium and strontium, but also inefficient regeneration of the resin prior to the coal seam water test.

Electrical and structural characterization of PVA/PEG polymer blend electrolyte films doped with NaClO4

A solid polymer blend electrolyte system based on polyvinyl alcohol (PVA) and polyethylene glycol (PEG) complexed with NaClO4 was prepared using solution cast technique. The structural properties of these electrolyte films were examined by X-ray diffractrometry (XRD) studies. The XRD data revealed that the amorphous domains of polymer blend matrix increased with increase of sodium salt concentration. The complexation of the salt with the polymer blend was confirmed by Fourier transform infrared (FTIR) studies. DC conductivity of the films was measured in the temperature range 303–398 K. The electrical conductivity increased with increasing dopant concentration, which is attributed to the formation of charge transfer complexes. The electrolyte exhibited the highest room temperature conductivity 2.41 × 10−6 S cm−1 at 30 % of NaClO4 salt concentration. The polymer complexes exhibited Arrhenius-type dependence of conductivity with temperature. In the temperature range studied, two regions with different activation energies were observed. Electrochemical cells of configuration Na/(PVA + PEG + NaClO4)/(I2 + C + electrolyte) were fabricated and the discharge characteristics of these cells were studied under a constant load of 100 K. Several cell parameters associated with the cells were evaluated and compared with earlier reports. UV-VIS absorption spectra in wavelength region 200–600 nm were used to evaluate the optical properties like direct band gap, indirect band gap and absorption edge. The optical band gaps decreased with increasing sodium ion concentration. This suggests that NaClO4 is a good dopant to improve the electrical properties of PVA + PEG polymer blend electrolytes.

Sea ice desalination under the force of gravity in low temperature environments

In winter 2009 and 2010, 9000m3 and 12,000m3 of sea ice, respectively, were collected from Bohai Bay and stored in a desalination pool. In 2009, the experiment lasted 80days, and produced 4500m3 of desalinated water with the salinity of 0.8‰. By contrast, the experiment of 2010 lasted 90days and yielded 6700m3 of water with the salinity of 1.4‰. Experimental results showed that under the force of gravity and low temperature, brine pockets within the sea ice were gradually drained out and sea ice was therefore converted from saline ice to freshwater ice. In this process, ambient temperature significantly affected drainage volume and salinity. When temperature rose, drainage volume increased and salinity decreased. Soluble salts decreased at different magnitudes during the course of gravity-induced desalination, in which chlorides showed the largest magnitude of decrease and sulfates the lowest. pH increased as a result of increasing sodium ion concentration. Insulation measures yielded higher rate of freshwater production by extending the duration of desalination. Shortening the period of desalination while maintaining high yield is worthy of further attention in studying gravity-induced sea ice desalination.

The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion® N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH.

Mechanism of the decreased food consumption and weight gain in rats following consumption of aqueous extract of the calyx of Hibiscus sabdariffa during pregnancy

Objective To investigate the possible mechanisms of the decreasing fluid and food consumption following Hibiscus sabdariffa (HS) consumption. Methods On the 1st day of pregnancy, rats were randomly divided into three groups with six animals per each group. One group was given tap water, one was given with extract at 0.6 g/100 mL while the third group was given with extract at 1.8 g/100 mL as their drinking solution. All groups received normal rat chow and drinking solution ad libitum. Fluid& food intake and weight were measured daily throughout pregnancy and Na + concentration in plasma was determined on the 18th day of pregnancy. Results Results showed decreased fluid and food consumption, decreased weight gain and increased sodium ion concentration in plasma of rats with HS extract compared with the control group. Conclusions Consumption of aqueous extract of the calyx of HS during pregnancy decreases food consumption and weight gain through mechanisms that may depend on Na + in HS content and elevating Na + concentration.

The Phosphorus Source Phytate Changes the Composition of the Cell Wall Proteome in Bacillus subtilis

Phytate is the most abundant phosphorus source in plants. Since Bacillus subtilis is a soil-dwelling bacterium, the focus of this study was to investigate whether it can use phytate as a phosphorus source. The extracellular proteome analysis revealed that phytate is an alternative phosphorus source to overcome the phosphate starvation response in B. subtilis. However, the phytase was not induced neither under phosphate starvation conditions nor by phytate addition. Surprisingly, the proteome analyses demonstrated a re-distribution of the major cell wall protease WprA from the cell wall to the extracellular medium in phytate-supplemented medium. In contrast, several cell wall proteins such as autolysins and autolysin modifier proteins (e.g., LytB, -C, -D, -E, -F) are increased in the cell wall proteome in response to phytate which is not accompanied by increased transcription of the corresponding genes. These effects of phytate on the composition of the B. subtilis cell wall proteome do not depend on the acidic conditions, the increased sodium ion concentration, and the increased cell lysis. In addition, the previously predicted as cytoplasmic protein oxalate decarboxylase OxdC was identified as the most abundant cell wall protein which was induced at the transcriptional level due to the acidic conditions caused by phytate.

Effect of Sodium Ion Concentration on Hydrogen Production from Sucrose by Anaerobic Hydrogen-producing Granular Sludge

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L −1(Na +), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000–2000mg·L −1(Na +)] for hydrogen production at 37°C, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6–413.1mg·L −1·h −1, 28.04–28.97ml·g −1, 7.52–7.83ml·g −1·h −1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g −1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.

A sodium ion sensor based on a covalently-linked aminorhodamine B–calix[4]arene chromoionophore

A fluorescent sodium optode based on a chromoionophore consisting of aminorhodamine B covalently-linked through an amide bond to a calix[4]arene has been developed. The optode, fashioned by incorporation of the chromoionophore into a single component polymer matrix, operates on the basis of on/off switching of aminorhodamine B fluorescence emission as a result of photo-induced intramolecular electron transfer, the efficiency of which is mediated by the complexation of sodium ions. The fluorescence intensity increased linearly with increasing sodium ion concentration in the range 0.01–2.0 M, exhibiting a three-fold enhancement over this range. The optode provides selectivity for sodium ions compared to potassium ions that is sufficient for clinical determinations of sodium ion concentration.

A Model for Hydration Interactions between Apoferritin Molecules in Solution

We have studied how non-DLVO forces between molecules of the globular protein apoferritin in solution affect its osmotic second virial coefficient. A model explaining the effects of the solution ionic strength and pH on the interprotein interaction is developed, to give a physical interpretation of recently published experimental findings showing that the second virial coefficient of the protein apoferritin, supported by acetate buffer, goes through a minimum as a function of ionic strength. At low ionic strengths, the apoferritin second virial coefficient initially decreases with increasing sodium ion concentration, as DLVO theory predicts. However, non-DLVO hydration forces due to overlapping of the Stern layers of the protein molecules increase the second virial coefficient with further increase of sodium ion concentration, again as found experimentally at higher ionic strengths. The non-DLVO effect arises from ionic exchange between hydrogen and sodium ions at the protein surface. An adsorption shell of hydrated sodium ions forms around the protein molecules with increasing buffer concentration.

Effect of Protonation on the Solution and Phase Behavior of Aqueous Sodium Myristate

Aqueous sodium myristate solutions have been shown to have unusually low dynamic tensions (1–10 mN/m) under pulsating area conditions. These solutions have no sharp solubility limit, evidently because they are protonated (or “hydrolyzed”) to form the much less soluble myristic acid and acid soaps. With no added electrolytes, the protonation fraction is 1% or less. The apparent protonation equilibrium “constant” increases with increasing concentration, indicating strong solution nonidealities, in addition to micellization. This protonation seems to affect the solution and phase behavior of aqueous sodium myristate strongly, as evidenced by the effect of added NaOH. Ion-selective electrodes (for Na+ and H+) and conductimetry indicate that at 25°C dissolved surfactant concentrations keep increasing well after dispersed particles are observed (2 mM). A cmc of about 4.5 mM, micelles of aggregation number n=70 and counterion binding parameter β=0.7 are inferred from these techniques. The cmc of sodium myristate increases slightly with temperature from 25 to 45°C. FTIR analysis of the filtered particles indicates that the dispersed particles are mainly acid soaps for concentrations less than 6 mM. With 10 mM NaOH, the particles observed above 2 mM consist mostly of sodium myristate. From both conductivity and IR data, the solubility of sodium myristate in water at 25°C is estimated to be about 6 mM, and as expected, it increases with increasing temperature and decreases with increasing sodium ion concentration.

Pressure dependence of the helix–coil transition temperature of poly[d(G‐C)

The pressure dependence of the helix-coil transition temperature (Tm) of poly[d(G-C)] was studied as a function of sodium ion concentration in phosphate buffer. The molar volume change of the transition (delta V) was calculated using the Clapeyron equation and calorimetrically determined enthalpies. The delta V of the transition increased from +4.80 (+/- 0.56) to +6.03 (+/- 0.76) mL mol-1 as the sodium ion concentration changed from 0.052 to 1.0M. The van't Hoff enthalpy of the transition calculated from the half-width of the differentiated transition displayed negligible pressure dependence; however, the value of this parameter decreased with increasing sodium ion concentration, indicating a decrease in the size of the cooperative unit. The volume change of the transition exhibits the largest magnitude of any double-stranded DNA polymer measured using this technique. For poly[d(G-C)] the magnitude of the change in delta V with sodium ion concentration (0.94 +/- 0.05 mL mol-1) is approximately one-half that observed for either poly[d(A-T)] or poly(dA).poly(dT). The delta V values are interpreted as arising from changes in the hydration of the polymer due to the release of counterions and changes in the stacking of the bases of the coil form. As a consequence of solvent electrostriction, the release of counterions makes a net negative contribution to the total delta V, implying that disruption of the stacking interactions contributes a positive volume change to the total delta V.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of sodium ion concentration on intrastrand base-pairing in single-stranded DNA.

The salt-induced formation of duplex structure (primarily hairpin loops) in denatured calf thymus DNA was monitored by measuring the decrease in absorbance at 260 nm as a function of increasing sodium ion concentration. It was found that this process was noncooperative and could be accurately described by the mass-action expression for the reversible formation of a binary complex: single strand (coil) + free sodium ion <==> hairpin (with associated sodium ion). The equilibrium constant for the transition was found to be 6 (M Na+)-1. The extrapolated absorbance at infinite salt concentration represents 11% hyperchromicity, which is one third of the hyperchromicity of denatured DNA in the absence of salt (36%).

Mechanisms of absorption of inorganic mercury from rat small intestine. I. Solvent drag effect on absorption of inorganic mercury.

A correlation of mercury absorption with water absorption was investigated by using the perfusion of rat small intestine with buffers containing 10(-4) M HgCl2. With a decrease in the osmolarity of the buffers or with increases in the sodium ion and urea concentrations in the buffers, absorption of water and mercury and accumulation of mercury in the intestinal tissue increased, and the increases in mercury absorption and accumulation were found to correlate with the increase in water absorption. Both the decrease in osmolarity and the increase in sodium ion concentration increased mercury accumulation in the epithelial cell after the perfusion. But these changes did not alter the mercury distribution in subcellular fractions. The results suggest that the increase in water absorption due to the hyptonicity or the increase in concentration of sodium ion or urea increases the mercury absorption and accumulation in the epithelial cell without change in the distributional pattern of mercury in the cell.

Polycyclic aromatic hydrocarbons physically intercalate into duplex regions of denatured DNA.

We have investigated the physical binding of pyrene and benzo[a]pyrene derivatives to denatured DNA. These compounds exhibit a red shift in their absorbance spectra of 9 nm when bound to denatured calf thymus DNA, compared to a shift of 10 nm when binding occurs to native DNA. Fluorescence from the hydrocarbons is severely quenched when bound to both native and denatured DNA. Increasing sodium ion concentration decreases binding of neutral polycyclic aromatic hydrocarbons to native DNA and increases binding to denatured DNA. The direct relationship between binding to denatured DNA and salt concentration appears to be a general property of neutral polycyclic aromatic hydrocarbons. Absorption measurements at 260 nm were used to determine the duplex content of denatured DNA. When calculated on the basis of duplex binding sites, equilibrium constants for binding of 7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydro-benzo[a]pyrene to denatured DNA are an order of magnitude larger than for binding to native DNA. The effect of salt on the binding constant was used to calculate the sodium ion release per bound ligand, which was 0.36 for both native and denatured DNA. Increasing salt concentration increases the duplex content of denatured DNA, and it appears that physical binding of polycyclic aromatic hydrocarbons consists of intercalation into these sites.

The effect of calcium and sodium ion concentration on the properties of dilute aqueous solutions of glycine conjugated bile salts: Phase behavior and solubility products of the calcium salts of the common glycine conjugated bile acids

A systematic examination was made of the effect of calcium and sodium ion concentrations on the phases present at 25°C and neutral pH of dilute aqueous solutions of four synthetically prepared, naturally occurring glycine conjugated bile salts: chenodeoxycholylglycine (CDCG), ursodeoxycholylglycine (UDCG), cholylglycine (CG), and deoxycholylglycine (DCG). Approximate solubility products [ a Ca 2+ · (B −) 2] were measured, using the assumption that the precipitates had the simplest possible stoichiometric composition for calcium bile salts. Values obtained were: CDCG, 0.2 × 10 −8; DCG, 1 × 10 −8; and UDCG, 4 × 10 −8. The value for CG was considerably higher. Precipitation was remarkably slow in all cases and often occurred after the intermediate formation of metastable, nonmicellar viscoelastic gels. Equilibrium was often not reached after 20 months. Precipitation was prevented or reduced by calcium ion binding to micelles (whose formation was favored by increased sodium ion concentration) and also by binding to monomers, i.e., by the formation of a soluble complex in the absence of micelles. Addition of phosphatidylcholine to a CDCG solution favored micelle formation and reduced precipitation. A mixture of bile salts simulating that present in human bile (CDCG:CG:DCG, 2:2:1) showed little change upon addition of calcium ions and only solutions low in Na + and close to the critical micellar concentration gave a glassy precipitate depleted in CG. Thus, the rarity of precipitation in bile of calcium glycine conjugated bile salts in vivo despite stoichiometric concentrations of both components much in excess of solubility products is due to: (1) lowered bile salt activity by micelle formation, (2) lowered calcium activity by binding to bile salt micelles and monomers (in addition to other biliary constituents), (3) lowered activity of both ions because of the high ionic strength of bile, and (4) slowness of precipitation and formation of metastable gels rather than crystalline precipitates.

Mechanical properties of borate crosslinked poly(vinyl alcohol) gels

AbstractBoric acid does not introduce crosslinks in poly(vinyl alcohol) solutions, but gelation does occur in the presence of cations. In this experimental study, the dynamic mechanical properties of these gels were determined using test‐tube torsion pendulums and an air‐bearing torsion pendulum. The modulus at a fixed concentration of polymer and boric acid increases with increasing sodium ion concentration up to the point where the atom ratio of sodium to boron reaches 1. Higher sodium concentrations do not increase the modulus. The log decrement, on the other hand, decreases with increasing sodium concentration continuously without reaching a plateau at the equal atom ratio. Log decrements as low as 0.02 can be measured. The storage modulus depends on the logarithm of borate concentration and on the 4.7 power of poly(vinyl alcohol) concentration. Only a very small portion of the borates in solution take part in effective crosslinks. The activation energy for breaking individual bonds in a function of temperature and the cation to boron ratios. At a fixed cation concentration, this activation energy is more negative with increasing amount of boron ions due to a transformation of monomeric crosslinks into polymeric crosslinks, so that the storage modulus which measures crosslink density decreases as a temperature rises.