Rate Of Na Research Articles

Enhanced Na+ and Cl− sequestration and secretion selectivity contribute to high salt tolerance in the tetraploid recretohalophyte Plumbago auriculata Lam.

Enhanced secretion of Na+ and Cl- in leaf glands and leaf vacuolar sequestration of Na+ or root retention of Cl-, combined with K+ retention, contribute to the improved salt tolerance of tetraploid recretohalophyte P. auriculata. Salt stress is one of the major abiotic factors threatening plant growth and development, and polyploids generally exhibit higher salt stress resistance than diploids. In recretohalophytes, which secrete ions from the salt gland in leaf epidermal cells, the effects of polyploidization on ion homeostasis and secretion remain unknown. In this study, we compared the morphology, physiology, and ion homeostasis regulation of diploid and autotetraploid accessions of the recretohalophyte Plumbago auriculata Lam. after treatment with 300mM NaCl for 0, 2, 4, 6, and 8 days. The results showed that salt stress altered the morphology, photosynthetic efficiency, and chloroplast structure of diploid P. auriculata to a greater extent than those of its tetraploid counterpart. Moreover, the contents of organic osmoregulatory substances (proline and soluble sugars) were significantly higher in the tetraploid than in the diploid, while those of H2O2 and malondialdehyde (MDA) were significantly lower. Analysis of ion homeostasis revealed that the tetraploid cytotype accumulated more Na+ in stems and leaves and more Cl- in roots but less K+ loss in roots compared with diploid P. auriculata. Additionally, the rate of Na+ and Cl- secretion from the leaf surface was higher, while that of K+, Mg2+, and Ca2+ secretion was lower in tetraploid plants. X-ray microanalysis of mesophyll cells revealed that Na+ mainly accumulated in different cellular compartments in the tetraploid (vacuole) and diploid (cytoplasm) plants. Our results suggest that polyploid recretohalophytes require the ability to sequester Na+ and Cl-(via accumulation in leaf cell vacuoles or unloading by roots) and selectively secrete these ions (through salt glands) together with the ability to prevent K+ loss (by roots). This mechanism required to maintain K+/Na+ homeostasis in polyploid recretohalophytes under high salinity provides new insights in the improved maintenance of ion homeostasis in polyploids under salt stress.

Effect of double and triple-doping of sulfur, nitrogen and phosphorus on the initial coulombic efficiency and rate performance of the biomass derived hard carbon as anode for sodium-ion batteries

Hard Carbons (HCs) are widely investigated as anode materials for Sodium-ion batteries (SIBs), for the abundance of the precursors and their easy synthesis. However, the intercalation of Na+ in the HCs is a big challenge for the design of high-performance SIBs. Heteroatom-doping can effectively facilitate the intercalation of Na+ in the anode material. Herein, a series of double and triple-atom phosphorus-nitrogen, phosphorus-sulfur, nitrogen-sulfur and phosphorus-nitrogen-sulfur in the camphor wood (Cmph) derived-HCs are fabricated, and their electrochemical performances as anodes for SIBs are investigated. The P–N–S-Cmph delivers high initial coulombic efficiency (ICE) of 70.74%%, an outstanding rate performance and good cycling stability, maintaining a specific capacity of 280 mAh g−1 at 2000 mA g−1 after 500 cycles. The excellent performances of the anode materials are assigned to the synergetic effect of the heteroatom-doping of S, N and P enlarging the interlayer spacing of the doped-Cmph-HCs, increasing the intercalation/deintercalation rate of Na+ in the HCs; disposing more active sites for the Na+ storage. In addition, sulfur can reversibly react with Na+, reducing the irreversible consumption of Na+ by the surface functional groups. This work presents a simple and effective method of designing high performance anode materials for SIBs.

Perspective Compounds for Immobilization of Spent Electrolyte from Pyrochemical Processing of Spent Nuclear Fuel

Immobilization of spent electrolyte–radioactive waste (RW) generated during the pyrochemical processing of mixed nitride uranium–plutonium spent nuclear fuel is an acute task for further development of the closed nuclear fuel cycle with fast neutron reactors. The electrolyte is a mixture of chloride salts that cannot be immobilized directly in conventional cement or glass matrix. In this work, a low-temperature magnesium potassium phosphate (MPP) matrix and two types of high-temperature matrices (sodium aluminoironphosphate (NAFP) glass and ceramics based on bentonite clay) were synthesized. Two systems (Li0.4K0.28La0.08Cs0.016Sr0.016Ba0.016Cl and Li0.56K0.40Cs0.02Sr0.02Cl) were used as spent electrolyte imitators. The phase composition and structure of obtained materials were studied by XRD and SEM-EDS methods. The differential leaching rate of Cs from MPP compound and ceramic based on bentonite clay was about 10−5 g/(cm2·day), and the rate of Na from NAFP glass was about 10−6 g/(cm2·day). The rate of 239Pu from MPP compound (leaching at 25 °C) and NAFP glass (leaching at 90 °C) was about 10−6 and 10−7 g/(cm2·day), respectively. All the synthesized materials demonstrated high hydrolytic, mechanical compression strength (40–50 MPa) even after thermal (up to 450 °C) and irradiation (up to 109 Gy) tests. The characteristics of the studied matrices correspond to the current requirements to immobilized high-level RW, that allow us to suggest these materials for industrial processing of the spent electrolyte.

The effect of initiating neuraxial analgesia service on the rate of cesarean delivery in Hubei, China: a 16-month retrospective study

BackgroundNo Pain Labor &Delivery (NPLD) is a nongovernmental project to increase access to safe neuraxial analgesia through specialized training. This study explores the change in overall cesarean delivery (CD) rate and maternal request CD(MRCD) rate in our hospital after the initiation of neuraxial analgesia service (NA).MethodsNA was initiated in May 1st 2015 by the help of NPLD. Since then, the application of NA became a routine operation in our hospital, and every parturient can choose to use NA or not. The monthly rates of NA, CD, MRCD, multiparous women, intrapartum CD, episiotomy, postpartum hemorrhage (PPH), operative vaginal delivery and neonatal asphyxia were analyzed from January 2015 to April 2016.ResultsThe rate of NA in our hospital was getting increasingly higher from 26.1% in May 2015 to 44.6% in April 2016 (p < 0.001); the rate of CD was 48.1% (3577/7360) and stable from January to May 2015 (p>0.05), then decreased from 50.4% in May 2015 to 36.3% in April 2016 (p < 0.001); the rate of MRCD was 11.4% (406/3577) and also stable from January to May 2015 (p>0.05), then decreased from 10.8% in May 2015 to 5.7% in April 2016 (p < 0.001). At the same time, the rate of multiparous women remained unchanged during the 16 month of observation (p>0.05). There was a negative correlation between the rate of NA and rate of overall CD, r = − 0.782 (95%CI [− 0.948, − 0.534], p<0.001), and between the utilization rate of NA and rate of MRCD, r = − 0.914 (95%CI [− 0.989, − 0.766], p<0.001). The rates of episiotomy, PPH, operative vaginal delivery and neonatal asphyxia in women who underwent vaginal delivery as well as the rates of intrapartum CD, neonatal asphyxia, and PPH in women who underwent CD remained unchanged, and there was no correlation between the rate of NA and anyone of those rates from January 1st 2015 to April 30th 2016 (p>0.05).ConclusionsOur study shows that the rates of CD and MRCD in our department were significantly decreased from May 1st 2015 to April 30th 2016, which may be due to the increasing use of NA during vaginal delivery with the help of NPLD.

Exchangeable cation effects on hot water extractable carbon and nitrogen in agricultural soils

Hot water is believed to extract bio-available soil organic matter (SOM), including organic compounds from the biomass of soil microbes. The role of soil physico-chemical factors in relation to extractability of SOM in hot water is not well understood. We evaluated the influence of exchangeable sodium (Na) on the quantity and quality of organic matter extracted in hot water from soils with a range of total and extractable C (total C 19–60 g kg–1; hot water extractable C (HWC) 659–3292 mg kg–1). The soils were pre-treated with different rates of Na (0–156 cmolc kg–1, as NaCl) to establish a range of exchangeable Na percentages (ESP), and then extracted with hot water (80°C) for 16 h. Hot water extractable C increased linearly as ESP increased, but the rate of increase differed between soils (the increase in HWC per unit increase in ESP ranged within 19–71 mg kg–1). At ESP 15, a threshold used to separate sodic and non-sodic soils, HWC was 30–60% greater than that measured without added Na. Ultraviolet absorbance (260 nm) data indicated that aromatic organic matter was preferentially released following Na pre-treatment. The proportion of HWC in phenolic form was generally little affected by Na treatment but there was a consistent increase in protein in response to Na (hot water extractable organic N in protein form increased from an average of 5.5 ± 2.2% without added Na to 11.0 ± 3.6% at the highest Na rate). The Na-induced increases in UV absorbance may be largely attributable to release of proteins containing aromatic amino acids (tryptophan and tyrosine). Our results suggest that organic matter desorbed from mineral surfaces may be an important contributor to hot water extractable C and N, and factors that affect the adsorption–desorption process may significantly influence organic matter extractability in hot water.

Expression levels of vacuolar ion homeostasis-related genes, Na+ enrichment, and their physiological responses to salt stress in sugarcane genotypes.

Sugarcane is a sugar-producing crop widely grown in tropical regions in over 120 countries of the world. Salt-affected soil is one of the most significant abiotic constraints that inhibit growth and crop productivity, and, consequently, reduce sucrose concentration in the stalk. The present study investigated vacuolar ion homeostasis, Na+ accumulation, and physiological and morphological adaptations under salt stress in two different sugarcane genotypes (salt-tolerant K88-92 and salt-sensitive K92-80) under greenhouse conditions. Na+ was rapidly absorbed by the root tissues of both sugarcane genotypes within 3-7 days of 150 mM NaCl treatment, as confirmed by the results of CoroNa Green fluorescence staining. In addition, the rate of Na+ translocation from roots to shoots was evidently reduced, leading to lower amount of Na+ in the leaf tissues. At the cellular level, expression of ShNHX1 (vacuolar Na+/H+ antiporter), ShV-PPase (vacuolar H+-pyrophosphatase), and ShV-ATPase (vacuolar H+-ATPase) was upregulated in salt-stressed plants for the compartmentation of Na+ into the vacuoles of root cells. Interestingly, sucrose, glucose, and fructose in root tissues of salt-stressed sugarcane cv. K88-92 were increased by 10.61, 5.58, and 1.81 folds, respectively, over the control. Total soluble sugars in the roots and free proline in the leaves of sugarcane cv. K88-92 (salt-tolerant) were enriched by 3.08 and 1.99 folds, respectively, when plants were exposed to 150 mM NaCl, leading to maintain better photosynthetic abilities, net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (E), and water use efficiency (WUE) in sugarcane cv. K88-92 than those in cv. K92-80. The study concludes that Na+ compartmentation in the root tissue acts as a major defense mechanism in sugarcane, especially in salt-tolerant genotype.

In vitro and in silico docking studies of antibacterial compounds derived from endophytic Penicillium setosum

Occasionally, endophytic fungal species cognize as a hidden prospective source of plant secondary metabolites. In this study, a potent Penicillium setosum sp. nov. was explored for its detailed antibacterial action on Escherichia coli and Staphylococcus aureus through different in vitro and in silico assays. Fluorescence based viability assay determined increase in the number of dead cells in course of time with the continual exposure of extract during a 4 h period. Scanning electron micrographs reflect the distinguishable morphological changes in treated cells, namely shortening of size, bubbles, and blisters on the surface of E. coli, as well as open holes and deep craters on the surface of S. aureus, ultimately leading to rupture of cells. Significant intracellular changes in bacteria were remarkably noticed through different membrane permeabilization assays. The rate of Na+ and K+ leakage with respect to time, intracellular material and cytoplasmic β-galactosidase release were measured spectroscopically. The results indisputably prove that membrane disruption of S. aureus cells occurs within 2 h and in E.coli occurs in between 2 and 4 h of exposure. Crude extract of P. setosum was fractioned using semi-preparative HPLC and the separated antibacterial active fraction showed antibacterial efficacy with the minimum inhibitory concentration of 8 μg/mL against both organisms. Active fraction contains four well-known plant metabolite belongs to the polyphenolic group (Leucodelphinidin, dihydroquercetin, kaempferol, and quercetin) and one polyketide (patulin) familiar as fungal metabolite, identified through high resolution LC-MS. Interaction mechanisms of identified compounds with nine important antimicrobial drug targets showed highest binding affinity by leucodelphinidin followed by dihydroquercetin > kaempferol > quercetin. This is the first instance of using leucodelphinidin and dihydroquercetin for detailed interaction study with multiple targets, and it was found that they showed more effective interaction than quercetin, which was earlier utilized for antibacterial studies.

Biochemical characterization and chemical inhibition of PfATP4-associated Na+-ATPase activity in Plasmodium falciparum membranes

The antimalarial activity of chemically diverse compounds, including the clinical candidate cipargamin, has been linked to the ATPase PfATP4 in the malaria-causing parasite Plasmodium falciparum The characterization of PfATP4 has been hampered by the inability thus far to achieve its functional expression in a heterologous system. Here, we optimized a membrane ATPase assay to probe the function of PfATP4 and its chemical sensitivity. We found that cipargamin inhibited the Na+-dependent ATPase activity present in P. falciparum membranes from WT parasites and that its potency was reduced in cipargamin-resistant PfATP4-mutant parasites. The cipargamin-sensitive fraction of membrane ATPase activity was inhibited by all 28 of the compounds in the "Malaria Box" shown previously to disrupt ion regulation in P. falciparum in a cipargamin-like manner. This is consistent with PfATP4 being the direct target of these compounds. Characterization of the cipargamin-sensitive ATPase activity yielded data consistent with PfATP4 being a Na+ transporter that is sensitive to physiologically relevant perturbations of pH, but not of [K+] or [Ca2+]. With an apparent Km for ATP of 0.2 mm and an apparent Km for Na+ of 16-17 mm, the protein is predicted to operate at below its half-maximal rate under normal physiological conditions, allowing the rate of Na+ efflux to increase in response to an increase in cytosolic [Na+]. In membranes from a cipargamin-resistant PfATP4-mutant line, the apparent Km for Na+ is slightly elevated. Our study provides new insights into the biochemical properties and chemical sensitivity of an important new antimalarial drug target.

Effect of various electrolytes on the electrochemical properties of Ni(OH)2 nanostructures

Hexagonal nanoplates of Ni(OH)2 with a thickness of ∼11 nm were synthesized by a simple hydrothermal method. The formation of Ni(OH)2 phase was confirmed by XRD technique. TEM images revealed a stack of hexagonal nanosheets with average nanoplates size of ∼62 nm. XPS results confirm the elemental compositions at the surface of Ni(OH)2 which are in good agreement with XRD results. As we know, the properties of electrolyte affect the performance of supercapacitors. Therefore, the electrochemical performance of Ni(OH)2 electrodes were investigated in various aqueous electrolyte solutions including 1M NaOH, 2M KOH, and 1M KOH mixed with 0.5M Na2SO4. The electrochemical results show that the Ni(OH)2 electrode in 1M NaOH electrolyte reached the highest specific capacitance of 447 F/g at a current density of 1 A/g that was nearly two times higher than that in the 2M KOH electrolyte. This can be attributed to the smaller ionic radius of the Na+ ion and a higher intercalation/deintercalation rate of Na+ ions into the surface of the Ni(OH)2 electrode. In addition, a coulombic efficiency of 94% was found in 1M NaOH at a current density of 10 A/g. The capacitance retention of the Ni(OH)2 electrode in 1M NaOH was maintained at about 100% after 1000 cycles. The present work proves that the best performance of Ni(OH)2 nanoplates was performed in the 1M NaOH electrolyte.

Possible implications of a reactor-status effect on the β+ decay rate of 22Na

Recently, a reproducible reactor-status effect was measured for the decay of [Formula: see text]Na. However, the effect was not observable for the [Formula: see text] decay of [Formula: see text]Co. Since no systematic cause for this effect was found, the possibility exists that it is caused by an interaction of reactor antineutrinos with the source nucleus. The observed effect is 18 orders of magnitude larger than for the antineutrino capture of a free proton. A possible explanation is a final-state interaction between the incoming antineutrino and a neutrino in the source nucleus. The effect has still to be confirmed by an independent measurement. In this paper, the consequences for applications in monitoring nuclear facilities are discussed, as well as the consequences for fundamental physics and the opportunities for resolving some outstanding questions about neutrino properties.

Salinization of the soil solution decreases the further accumulation of salt in the root zone of the halophyte Atriplex nummularia Lindl. growing above shallow saline groundwater.

Water use by plants in landscapes with shallow saline groundwater may lead to the accumulation of salt in the root zone. We examined the accumulation of Na+ and Cl- around the roots of the halophyte Atriplex nummularia Lindl. and the impacts of this increasing salinity for stomatal conductance, water use and growth. Plants were grown in columns filled with a sand-clay mixture and connected at the bottom to reservoirs containing 20, 200 or 400mM NaCl. At 21d, Na+ and Cl- concentrations in the soil solution were affected by the salinity of the groundwater, height above the water table and the root fresh mass density at various soil depths (P<0.001). However, by day 35, the groundwater salinity and height above the water table remained significant factors, but the root fresh mass density was no longer significant. Regression of data from the 200 and 400mM NaCl treatments showed that the rate of Na+ accumulation in the soil increased until the Na+ concentration reached ~250mM within the root zone; subsequent decreases in accumulation were associated with decreases in stomatal conductance. Salinization of the soil solution therefore had a feedback effect on further salinization within the root zone.

Phase Evolution and Surface Morphology of Niobate Hydrate Template Nanoparticles Synthesized by Hydrothermal Method

In this work, an alternative approach to synthesize (K,Na)NbO3 (KNN) particles is investigated. KNN hydrate particles were prepared by hydrothermal method in a mixed alkaline solution with different KOH/(KOH+NaOH) ratios , and phase structure as well as surface morphology of these niobate hydrate particles were systematically studied. For the reaction rate of Na+ is faster than K+, a mixed alkaline solution with K+/Na+ changing from 4/1 to 5/1was required as a starting solution so a to obtain KNN hydrate particles with K/Na=1. Besides, the results show that particle size of KNN hydrate particles synthesized in different starting solution is dependent on K+/Na+ of the starting solution, and grain size of as-sintered KNN ceramics through hydrothermal method decreases sharply.

English

This study was conducted to determine the effect of plant growth promoting rhizobacteria Azotobacter chroococcum AZ6 isolated from arid soil and osmolytes such as glycine betaine (GB) or proline (P) on the growth of durum wheat varieties under salinity stress. Inoculation by A. chroococcum AZ6 in the presence or absence of P (5 mM) or GB (5 mM) reduced substantially the effect of salt stress on plant growth parameters such as root length, plant height, fresh shoot and root weight and dry shoot and root weight. The differences between the two varieties were low but with a fresh and dry weight higher in Waha. The rate of Na+ accumulation in the roots and the shoots was important up to 100 mM and increased at 200 mM. The K+ concentration and chlorophyll content decreased but proline and amino acid contents were enhanced with increasing salinity. Treatment by inoculation in the presence or absence of osmolytes improved the chlorophyll (a and total) and the K+ concentrations and reduced intracellular proline accumulation and amino acids contents. Also, as result, the use of A. chroococcum AZ6 and osmolytes treatment may provide a means of improving tolerance of durum wheat to salt stress. Key words: Durum wheat, salinity, osmolytes, Azotobacter chroococcum,

THE ION-EXCHANGE PROPERTIES OF NATURAL ZEOLITE MORDENITE

The cation exchange properties of mordenite (a Nakhchivan natural zeolite) were studied. Ion exchange of the original cations - sodium, potassium and calcium - by magnesium, strontium, cadmium, zinc and nickel cations was carried out. It was found that in the case of Zn cations cation exchange occurs readily at a high speed and the maximum value of the degree of exchange. A low value of the degree of cation exchange is observed for Mg. This is due to the large hydration shell of magnesium, which adversely affects the cation exchange. High values of the exchange rate of Na+ cations have already been explained at the first exchange of low content of sodium cations and their location mostly in exchange for positions available. The lesser ability to exchange K+, Na+ cations than contained in the natural zeolite is due to several reasons. With an increasing number of degrees of ionic exchange value exchangeable cations K+ vary to a greater degree than the degree of exchange of the cations Na+. Firstly, the content and size of the K+ cation are greater than those of the Na+ cations. Furthermore, a part of the K+ cations is in exchange for hard cancrinites cells. It has been found that the degree of cation exchange of K+ (αK), contained in the original zeolite, with Mg2+, Ni2+, Sr2+, Zn2+, Cd2+ cations is considerably lower than the values of the degree of cation exchange of Na+ (αNa) at the same cations.

Soft X-ray Exposure Promotes Na Intercalation in Graphene Grown on Si-Face SiC.

An investigation of how electron/photon beam exposures affect the intercalation rate of Na deposited on graphene prepared on Si-face SiC is presented. Focused radiation from a storage ring is used for soft X-ray exposures while the electron beam in a low energy electron microscope is utilized for electron exposures. The microscopy and core level spectroscopy data presented clearly show that the effect of soft X-ray exposure is significantly greater than of electron exposure, i.e., it produces a greater increase in the intercalation rate of Na. Heat transfer from the photoelectrons generated during soft X-ray exposure and by the electrons penetrating the sample during electron beam exposure is suggested to increase the local surface temperature and thus the intercalation rate. The estimated electron flux density is 50 times greater for soft X-ray exposure compared to electron exposure, which explains the larger increase in the intercalation rate from soft X-ray exposure. Effects occurring with time only at room temperature are found to be fairly slow, but detectable. The graphene quality, i.e., domain/grain size and homogeneity, was also observed to be an important factor since exposure-induced effects occurred more rapidly on a graphene sample prepared in situ compared to on a furnace grown sample.

K+ accumulation in the cytoplasm and nucleus of the salt gland cells of Limonium bicolor accompanies increased rates of salt secretion under NaCl treatment using NanoSIMS

Recretohalophytes with specialized salt-secreting structures (salt glands) can secrete excess salts from plant, while discriminating between Na+ and K+. K+/Na+ ratio plays an important role in plant salt tolerance, but the distribution and role of K+ in the salt gland cells is poorly understood. In this article, the in situ subcellular localization of K and Na in the salt gland of the recretohalophyte Limonium bicolor Kuntze is described. Samples were prepared by high-pressure freezing (HPF), freeze substitution (FS) and analyzed using NanoSIMS. The salt gland of L. bicolor consists of sixteen cells. Higher signal strength of Na+ was located in the apoplast of salt gland cells. Compared with control, 200mM NaCl treatment led to higher signal strength of K+ and Na+ in both cytoplasm and nucleus of salt gland cells although K+/Na+ ratio in both cytoplasm and nucleus were slightly reduced by NaCl. Moreover, the rate of Na+ secretion per salt gland of L. bicolor treated with 200mM NaCl was five times that of controls. These results suggest that K+ accumulation both in the cytoplasm and nucleus of salt gland cells under salinity may play an important role in salt secretion, although the exact mechanism is unknown.

Pt(O,O'-acac)(γ-acac)(DMS)] alters SH-SY5Y cell migration and invasion by the inhibition of Na+/H+ exchanger isoform 1 occurring through a PKC-ε/ERK/mTOR Pathway.

We previously showed that [Pt(O,O’-acac)(γ-acac)(DMS)] ([Pt(acac)2(DMS)]) exerted substantial cytotoxic effects in SH-SY5Y neuroblastoma cells, and decreased metalloproteases (MMPs) production and cells migration in MCF-7 breast cancer cells. The ubiquitously distributed sodium-hydrogen antiporter 1 (NHE1) is involved in motility and invasion of many solid tumours. The present study focuses on the effects of [Pt(acac)2(DMS)] in SH-SY5Y cell migration and also on the possibility that NHE1 may be involved in such effect. After sublethal [Pt(acac)2(DMS)] treatment cell migration was examined by wounding assay and cell invasion by transwell assay. NHE1 activity was measured in BCECF-loaded SH-SY5Y as the rate of Na+-dependent intracellular pH recovery in response to an acute acid pulse. Gelatin zymography for MMP-2/9 activities, Western blottings of MMPs, MAPKs, mTOR, S6 and PKCs and small interfering RNAs to PKC-ε/-δ mRNA were performed. Sublethal concentrations of [Pt(acac)2(DMS)] decreases NHE1 activity, inhibites cell migration and invasion and decreases expression and activity of MMP-2 and -9. [Pt(acac)2(DMS)] administered to SH-SY5Y cells provokes the increment of ROS, generated by NADPH oxidase, responsible for the PKC-ε and PKC-δ activation. Whilst PKC-δ activates p38/MAPK, responsible for the inhibition of MMP-2 and -9 secretion, PKC-ε activates a pathway made of ERK1/2, mTOR and S6K responsible for the inhibition of NHE1 activity and cell migration. In conclusion, we have shown a drastic impairment in tumour cell metastatization in response to inhibition of NHE1 and MMPs activities by [Pt(acac)2(DMS)] occurring through a novel mechanism mediated by PKC-δ/-ε activation.

In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of Supercritical CO2 Incorporation in Smectite–Natural Organic Matter Composites

This Article presents an in situ NMR study of clay–natural organic polymer systems (a hectorite–humic acid [HA] composite) under CO2 storage reservoir conditions (90 bar CO2 pressure, 50 °C). The 13C and 23Na NMR data show that supercritical CO2 interacts more strongly with the composite than with the base clay and does not react to form other C-containing species over several days at elevated CO2. With and without organic matter, the data suggest that CO2 enters the interlayer space of Na–hectorite equilibrated at 43% relative humidity. The presence of supercritical CO2 also leads to increased 23Na signal intensity, reduced line width at half height, increased basal width, more rapid 23Na T1 relaxation rates, and a shift to more positive resonance frequencies. Larger changes are observed for the hectorite–HA composite than for the base clay. In light of recently reported MD simulations of other polymer–Na–smectite composites, we interpret the observed changes to be due to an increase in the rate of Na+ s...

Serum and urine electrolyte changes following ligation of a left segmental renal artery in dogs

Background and Aim: Ligation of renal artery has been reported to cause acute reduction of nephron population resulting in altered Na + and K + excretion pattern. However, no study has reported electrolyte balance following the ligation of a branch of left renal artery. Methods: Segmental ligation of left renal arterial branch was performed in 18 dogs. Changes in the excretion pattern of Na + and K + and the urine flow rate by the remnant kidney have been observed. Serum and urine samples were collected before and after the ligation at 30-minute intervals for a period of two hours, and Na + and K + concentrations were determined along with the flow rate of urine. Results: A considerable reduction in the urinary excretion rate of Na + and K + was observed in 30 minutes after the ligation. Subsequently, a gradual rise in the rate of excretion of Na + and K + towards pre-ligation values was observed by the end of 120 minutes. Statistically significant increase in K + concentration in urine was observed at the end of two hours ( P = 0.023). The serum analysis for both the electrolytes in all experiments showed no significant changes in concentrations. Conclusion: Findings of the present study suggest that ligation of an artery segment in the kidney though affects acute changes in K + , it does not affect the overall homeostasis of either water or electrolytes. The maintenance of homeostasis might be achieved through the improvement of function by the remnant kidney.

Identifying cellular mechanisms of zinc-induced relaxation in isolated cardiomyocytes

We tested several molecular and cellular mechanisms of cardiomyocyte contraction-relaxation function that could account for the reduced systolic and enhanced diastolic function observed with exposure to extracellular Zn(2+). Contraction-relaxation function was monitored in isolated rat and mouse cardiomyocytes maintained at 37°C, stimulated at 2 or 6 Hz, and exposed to 32 μM Zn(2+) or vehicle. Intracellular Zn(2+) detected using FluoZin-3 rose to a concentration of ∼13 nM in 3-5 min. Peak sarcomere shortening was significantly reduced and diastolic sarcomere length was elongated after Zn(2+) exposure. Peak intracellular Ca(2+) detected by Fura-2FF was reduced after Zn(2+) exposure. However, the rate of cytosolic Ca(2+) decline reflecting sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2a) activity and the rate of Na(+)/Ca(2+) exchanger activity evaluated by rapid Na(+)-induced Ca(2+) efflux were unchanged by Zn(2+) exposure. SR Ca(2+) load evaluated by rapid caffeine exposure was reduced by ∼50%, and L-type calcium channel inward current measured by whole cell patch clamp was reduced by ∼70% in cardiomyocytes exposed to Zn(2+). Furthermore, ryanodine receptor (RyR) S2808 and phospholamban (PLB) S16/T17 were markedly dephosphorylated after perfusing hearts with 50 μM Zn(2+). Maximum tension development and thin-filament Ca(2+) sensitivity in chemically skinned cardiac muscle strips were not affected by Zn(2+) exposure. These findings suggest that Zn(2+) suppresses cardiomyocyte systolic function and enhances relaxation function by lowering systolic and diastolic intracellular Ca(2+) concentrations due to a combination of competitive inhibition of Ca(2+) influx through the L-type calcium channel, reduction of SR Ca(2+) load resulting from phospholamban dephosphorylation, and lowered SR Ca(2+) leak via RyR dephosphorylation. The use of the low-Ca(2+)-affinity Fura-2FF likely prevented the detection of changes in diastolic Ca(2+) and SERCA2a function. Other strategies to detect diastolic Ca(2+) in the presence of Zn(2+) are essential for future work.