Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Na2SO4”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1996

Cyanocarbons as ligands for electron donor acceptor chromatography of human serum proteins.

The adsorption of human serum proteins to mono-, di- and tri-cyanocarbon ligands was studied in the presence of the water-structuring salt Na2SO4. All of the ligands adsorbed proteins to varying degrees when coupled to agarose via a divinylsulfone-derived spacer arm (DVS), whereas an insignificant or very low protein adsorption capacity occurred when the ligands were coupled through the bisoxirane-derived spacer arm. Studies of the DVS-coupled cyanocarbons showed that adsorption capacity increases with the number of cyano substituents carried by the ligand. The selectivity toward human serum proteins appeared to be similar to that of other electron acceptor ligands, but different from that of hydrophobic ligands. Tricyanoaminopropene-DVS-agarose was found to be the most potent protein adsorbent.

Blood Proteins↗
PubMed1997

Optimized method for the determination of organophosphorus pesticides in meat and fatty matrices.

A method was developed and optimized for determination of residues of organophosphorous pesticides (OPs) in meat and fatty matrices. The method was developed for the national Danish monitoring programme, whereby priority was given to simplify the clean-up, avoid use of toxic and harmful organic solvents and allow quantification at ppb level using GC with nitrogen-phosphorus detection (NPD). Homogenized meat was extracted using ethyl acetate, the co-extracted water being removed using anhydrous Na2SO4. The clean-up was done through fat precipitation by cooling the extract flowed by solid-phase extraction on C18 mini-columns. Pesticide residues were determined by GC-NPD using a DB1701 capillary column. The limit of detection was 1 to 20 ppb and limit of determination was 2 to 33 ppb and the method is feasible for control of fat-soluble OPs according to the maximum residue limits set by the European Communities. The method developed covers a broad polarity range from polar OPs, such as acephate and methamidophos, through medium polar OPs to non-polar pesticides, such as prothiofos.

Chromatography, Gas↗
PubMed1999

Analysis of beta-N-oxalyl-L-alpha,beta-diaminopropionic acid and homoarginine in Lathyrus sativus by capillary zone electrophoresis.

A simple capillary zone electrophoresis (CZE) method has been developed for the simultaneous quantitative determination of beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (beta-ODAP) and homoarginine in Lathyrus sativus (LS; grass pea). A new Na2B4O7-Na2SO4 run buffer was used and the pH was 9.20, contents of beta-ODAP and homoarginine in crude extracts of LS plant material were determined with this method, the RSDs of peak areas of beta-ODAP and homoarginine were 2.62% and 3.61%, respectively. It was found that the equilibrium concentration ratio of alpha- and beta-ODAP decreased from 34.5/65.5 to 28.6/71.4 when the pH of the solution increased from pH 3.0 to pH 11.0.

Amino Acids, Diamino↗
PubMed1998

Salt taste responses of the IXth nerve in Sprague-Dawley rats: lack of sensitivity to amiloride.

To explore characteristics of the salt taste function of taste receptor cells located on the posterior tongue, we recorded electrophysiological responses from the whole glossopharyngeal nerve in Sprague-Dawley (SD) rats. For all salts, relative response magnitudes increased with increased stimulus concentrations (0.2-2.0 M) of NH4+, K+, and Na+ salts. The order of effectiveness of stimulation for Cl- salts was NH4Cl > KCl > NaCl. For sodium salts, relative response magnitudes were anion dependent. Sodium salts with small anions (NaCl, NaSCN, and NaNO3) had a much stronger stimulating effect than sodium salts with large anion groups (Na2SO4, C2H3O2Na, and C6H11O7Na). The responses of the glossopharyngeal nerve to the Na+ salts of NaCl, C2H3O2Na, and C6H11O7Na were not inhibited by the lingual application of the epithelial sodium transport blocker amiloride. This is in contrast to large amiloride sensitivity of the chorda tympani nerve. Amiloride also failed to inhibit the responses to K+ salts (KCl and KC2H3O2) and to NH4Cl. These results demonstrate that taste receptors innervated by the glossopharyngeal nerve in SD rats lack amiloride sensitivity as observed in the glossopharyngeal nerve of spontaneously hypertensive and Wistar-Kyoto rats. Furthermore, the difference between the small-anion group and the large-anion group of Na+ salts in their effectiveness to produce responses in the glossopharyngeal nerve parallels the effects noted for the anion dependence in the portion of the taste response resistant to amiloride in the chorda tympani nerve. Sodium salts with the smaller anion produced the larger responses in both glossopharyngeal and chorda tympani nerves after amiloride.

Amiloride↗
PubMed1978

New substrates for the radioassay of angiotensin converting enzyme of endothelial cells in culture.

To develop means of measuring angiotensin converting enzyme of endothelial cells in culture, we have synthesized benzoyl-Phe-Ala-Pro-OH (I), benzoyl-Pro-Phe-Arg-OH (II) and benzoyl-Gly-His-Leu-OH (III), each bearing a 3H-atom on the para-position of its benzoyl moiety. All three of the acylated tripeptides are substrates for the enzyme. Substrate I exhibits the lowest Km (12.5 micrometer) and yields the most sensitive assay: the enzyme of 10(6) cells can be measured in a 30 min incubation at 37 degrees C. Radiolabelled reaction product is separated from substrate by extraction of acidified reaction mixture with an organic solvent, and the rate of formation of product can be quantified by liquid scintillation counting of the organic phase. Substrate III can also be used to measure angiotensin converting enzyme of cells but requires longer incubations (180--240 min) and high salt concentrations (0.75 M Na2SO4). Substrate II is not specific: it is hydrolyzed by more than one enzyme of endothelial cells.

Cells, Cultured↗
PubMed2002

Oxidation of diazinon by anodic Fenton treatment.

Anodic Fenton treatment (AFT) is a new technology that has several advantages over classic Fenton treatment and electrochemical Fenton treatment. The oxidation of diazinon by AFT using different electrolytes has been investigated. NaCl, KCl and Na2SO4 show similar effects on the extent and rate of oxidation, and the data can be fitted quite well by the AFT kinetics model. Use of NaNO3 as the electrolyte causes low-efficiency electrolysis and a subsequent low oxidation rate for diazinon. The NaCl concentration level in the anodic half-cell and the concentration ratio between the two half-cells is optimized at 0.04M and 4:1 (cathodic/anodic), respectively. The activation energy of diazinon oxidation by anodic Fenton treatment is estimated to be 12.6 +/- 0.6 kJ mol(-1), which is less than half of that for aqueous chlorine treatment. Diazoxon is the intermediary oxidation product. The oxidation of diazinon as a formulated product has also been investigated. Its dissipation kinetics can also be fitted quite well by the AFT model. Compared with the oxidation of pure diazinon, the oxidation rate of formulated diazinon is much lower, an indication that many formulation ingredients compete with diazinon for reaction with the hydroxyl radical.

Diazinon↗
PubMed2002

Aniline degradation by Electro-Fenton and peroxi-coagulation processes using a flow reactor for wastewater treatment.

The degradation of 10-30 l of a 1000 ppm aniline solution in 0.050 M Na2SO4 + H2SO4 at pH 3.0 and 40 degrees C by Electro-Fenton and peroxi-coagulation processes at constant current until 20 A has been studied using a pilot flow reactor in recirculation mode with a filter-press cell containing an anode and an oxygen diffusion cathode, both of 100 cm2 area. H2O2 is produced by the two-electron reduction of O2 at the cathode, being accumulated with a current efficiency between 60% and 80% at the first stages of electrolyses performed with a Ti/Pt anode. In the presence of 1 mM Fe2+, less H2O2 is accumulated, but it is not detected using an Fe anode. The Electro-Fenton process with 1 mM Fe2+ and a Ti/Pt or DSA anode yields an insoluble violet polymer, while the soluble total organic carbon (TOC) is gradually removed, reaching 61% degradation after 2 h at 20 A. In this treatment, pollutants are preferentially oxidized by hydroxyl radicals formed in solution from reaction of Fe2+ with H2O2. The peroxi-coagulation process with an Fe anode has higher degradation power, allowing to remove more than 95% of pollutants at 20 A, since some intermediates coagulate with the Fe(OH)3 precipitate formed. Both advanced electrochemical oxidation processes (AEOPs) show moderate energy costs, which increase with increasing electrolysis time and applied current.

Aniline Compounds↗
PubMed1998

The adsorption of heavy metals by different sorbents under various incineration conditions.

The emission of heavy metals can be controlled by adding solid sorbents into the combustion chamber during incineration processes. The objective of this work was to experimentally study the adsorption efficiency of different sorbents for heavy metals under various incineration conditions. Each sorbent has its optimum operating temperature. Kaolinite and aluminum oxide have the best adsorption efficiency at 800 degrees C, and bauxite is at 700 degrees C. The adsorption efficiencies of the three sorbents for the four heavy metals all follow the sequence of Pb > Cu > Cr > Cd. The presence of inorganic chloride (NaCl) and sulfate (Na2SO4) increases the adsorption efficiency of the sorbents, but organic chloride PVC decreases the adsorption efficiency.

Adsorption↗
PubMed1999

Effects of polydiallyldimethyl ammonium chloride coagulant on formation of chlorinated by products in drinking water.

The objectives of this research work was to evaluate the reduction of THM precursors by cationic p-DADMAC and determine the correlations between the chlorine demand and trihalomethane formation in the presence of electrolyte solutions and ambient light. The chlorine demand was found to be significantly reduced provided that the H2SO4 electrolyte was fed to the sample solutions. The amount of CHCl3 formation was also decreased when the Na2SO4 electrolyte was introduced in spite of the levels of light intensity. The p-DADMAC can not only effectively remove the turbidity but also reduce the formation of CHCl3. The optimum dosage of p-DADMAC for reducing the turbidity, TOC and CHCl3 in the humic acid and source water samples was determined and depended upon the nature of organics.

Allyl Compounds↗
PubMed1996

Differential scanning calorimetric studies on bovine serum albumin. IV. Effect of anionic surfactants with various lengths of hydrocarbon chain.

Using defatted and SH-blocked bovine serum albumin (BSA), measurements of differential scanning calorimetry (DSC) have been made at pH 7 on the complexes of BSA and a series of sodium alkyl sulfates used were sodium decyl sulfate (SDeS), sodium octyl sulfate (SOS), sodium hexyl sulfate (SHS) and sodium ethyl sulfate (SES). Results obtained were compared with those on the system BSA-sodium dodecyl sulfate (SDS) studied previously. Two peaks P1 and P2 existed in the DSC curve of BSA. These peaks originate in the heat-induced transition of BSA. The pattern of DSC curve changed with the amount of the ligand added, i.e. with the molar mixing ratio ligand/BSA (1). The change for systems BSA-SDeS, BSA-SOS and BSA-SHS was qualitatively the same as that for the system BSA-SDS (2). Interestingly, SES, which is not a surfactant, interacts with BSA. The change for the system BSA-SES was qualitatively the same as that for the system BSA-Na2SO4. All alkyl sulfates suppressed the heat-induced transition at lower concentrations. A linear relationship was obtained for the plots of log(D/A)1 versus log CMC, where (D/A)1 is the molar mixing ratio of anionic surfactant (D) to BSA (A) at which the most heat-stable complex is formed. This suggests that the hydrophobic force has a serious effect on the formation of heat-stable complexes.

Anions↗
PubMedDate not supplied

Novel method for the preparation of N-acylchitosan fiber and N-acylchitosan-cellulose fiber.

A novel method for the preparation of N-acylchitosan fiber and N-acylchitosan-cellulose fiber is described. Each aqueous solution of sodium N-acetyl and N-propionylchitosan salts in aqueous 14% NaOH was spun through a viscose-type spinneret at 10-15 degrees C into a coagulating bath containing aqueous 10%, H2SO4. 25% Na2SO4 and 1.3% ZnSO4 to afford the corresponding white fiber. By the same method, a clear solution of sodium N-acetyl and N-propionyl chitosan salts were respectively mixed with sodium cellulose xanthate in aqueous 14% NaOH and spun to afford the corresponding white N-acylchitosan-cellulose fiber. Their filament tenacity and elongation values were 0.4-0.7 times as large as cellulose. These fibers were digestible in reactions by chitinase and lysozyme, and the digestibility was controlled by the structure of the N-acyl group.

Bandages↗
PubMed2000

Synthesis and aqueous solution properties of multinuclear oxo-bridged vanadium(IV/V) complexes.

Reaction of the multifunctional phenolic ligands 2,5-bis[N,N-bis(carboxymethyl)aminomethyl]hydroquinone (H6cahq), 2,2'-bis[N,N-bis(carboxymethyl)aminomethyl]-4,4'-isopropylidenediphen ol(H6capd),2,2',2''-tris[N,N-bis(carboxymethyl)aminomethyl]-1,1 ,1-tris(4-hydroxyphenyl)ethane (H9catp) and the monofunctional 2-[N,N-bis(carboxymethyl)aminomethyl]-4-carboxyphenol (H3cacp), with VOSO4 and NaVO3 affords the oxo-bridged mixed-valence vanadium(IV/V) Na6[(VO)4(mu-O)2(mu-cahq)2] x Na2SO4 x 20H2O (1), HnNa(3-n)[(VO)2(mu-O)(mu-cacp)2] (2), HnNa(3-n)[(VO)4(mu-O)2(mu-capd)2] (3), HnNa(9-n)[(VO)6(mu-O)3(mu3-catp)2] (4). In addition to the synthesis, we report the infrared, magnetic, optical and electrochemical properties of these complexes. The hydrolytic stability at different pH values was also investigated using visible spectroscopy.

Electrochemistry↗
PubMed1996

Thermal stability of calf skin collagen type I in salt solutions.

The thermal stability of acid-soluble collagen type I from calf skin in salt solutions is studied by high-sensitivity differential scanning calorimetry. Three concentration ranges have been clearly distinguished in the dependence of collagen thermal stability on ion concentration. At concentrations below 20 mM, all studied salts reduce the temperature of collagen denaturation with a factor of about 0.2 degree C per 1 mM. This effect is attributed to screening of electrostatic interactions leading to collagen stabilisation. At higher concentrations, roughly in the range 20-500 mM, the different salts either slightly stabilise or further destabilise the collagen molecule in salt-specific way that correlates with their position in the lyotropic series. The effect of anions is dominating and follows the order H2PO4- > or = SO4(2-) > Cl- > SCN-, with sign inversion at about SO4(2-). This effect, generally known as the Hofmeister effect, is associated with indirect protein-salt interactions exerted via competition for water molecules between ions and the protein surface. At still higher salt concentrations (onset concentrations between 200 and 800 mM for the different salts), the temperature of collagen denaturation and solution opacity markedly increase for all studied salts due to protein salting out and aggregation. The ability of salts to salt out collagen also correlates with their position in the lyotropic series and increases for chaotropic ions. The SO4(2-) anions interact specifically with collagen - they induce splitting of the protein denaturation peak into two components in the range 100-150 mM Na2SO4 and 300-750 mM Li2SO4. The variations of the collagen denaturation enthalpy at low and intermediate salt concentrations are consistent with a weak linear increase of the enthalpy with denaturation temperature. Its derivative, d(delta H)/dT, is approximately equal to the independently measured difference in the heat capacities of the denatured and native states, delta Cp = Cp(D) - Cp(N) approximately 0.1 cal.g-1 K-1.

Animals↗
PubMed2001

The effect of salinity on the emergence and seedling growth of Picea mariana, Picea glauca, and Pinus banksiana.

Mining operations in areas of the boreal forest have caused salinity issues to be a major concern for reclamation. One of the factors determining successful reclamation is the ability of species to self-propagate. The effects of salinity on the seedling emergence and early growth of three boreal forest conifers: Picea mariana, Picea glauca, and Pinus banksiana were determined. Seeds were planted in sand moistened with solutions of various concentrations of sodium chloride or sodium sulfate. Seedling emergence was monitored on a daily basis and growth parameters assessed after 6 weeks. The emergence of Pinus banksiana seedlings was least affected by salinity, and at certain concentrations, emergence even appeared to be stimulated by the presence of salt. Picea glauca was the most sensitive of the species studied. Hypertrophia was observed in all species at high concentrations of Na2SO4, and an increase in salt levels caused a corresponding reduction in seedling height and weight, root length and number of lateral roots.

Environmental Monitoring↗
PubMed2000

Electrocatalytic oxidation of NADH at the self-assembled monolayer of nickel(II) macrocycle on gold electrode.

Electroactive self-assembled monolayers (SAMs) of macrocyclic Ni(II) complex (1) were fabricated on gold electrode and its electrochemistry has been studied in different supporting electrolytes. Substantial stabilization of tervalent nickel and a significant negative shift of formal potential of the Ni(3+/2+) couple have been observed when the supporting electrolyte is changed from nitrate to phosphate. Coordination of supporting electrolyte anion with the Ni(III) complex shifts the formal potential and thus tervalent nickel is stabilized. SAM of 1 electrode shows an excellent electrocatalytic activity towards the oxidation of NADH in aqueous NaNO3 solution, whereas it scarcely catalyzes the oxidation of NADH in aqueous phosphate buffer solution. The electrocatalytic oxidation of NADH in Na2SO4 solution is less efficient than that in NaNO3 solution. The anion-dependent electrocatalysis has been discussed on the basis of the difference in the coordinating ability of the anions with the tervalent nickel centers. Steady-state current has been measured for the oxidation of NADH and it was proportional to the concentration of NADH.

Catalysis↗
PubMed1999

Photoinduced electron transfer from synthetic chlorophyll analogue to fullerene C60 on carbon paste electrode. Preparation of a novel solar cell.

Upon a carbon paste electrode, fullerene C60 and successively methyl pyropheophorbide-a (chlorin) were casted to prepare a chlorin-fullerene modified carbon paste electrode (CFE). Photocurrents on the CFE were produced by irradiating of visible lights (> 510 nm) in an aqueous solution of 0.05 M ethylenediaminetetraacetic acid and 0.1 M Na2SO4 at pH 6.7. Larger anodic photocurrent was induced by the CFE than by the carbon paste electrodes modified with either the fullerene or the chlorin. In addition, the photocurrent of the CFE was dependent upon the amount of fullerene casted. The photocurrent action spectra of the CFE (at 300 mV vs. Ag/Ag+) showed that photoinduced electron transfer occurred from the excited state of the chlorin to the fullerene and/or from the chlorin to the photoexcited fullerene, and the electron of the fullerene anion radical produced was then shifted to the carbon paste. Upon irradiation of > 375 nm lights, the anodic photocurrent of the CFE was enhanced by increase in the illuminated light power and reached 0.03 mA cm-2 in the present system.

Carbon↗
PubMed2000

Drowning-out crystallisation of sodium sulphate using aqueous two-phase systems.

A novel method to obtain crystals of pure, anhydrous salt, using aqueous two-phase systems was studied. A concentrated salt solution is mixed with polyethylene glycol (PEG), upon which three phases are formed: salt crystals, a PEG-rich liquid and a salt-rich liquid. After removal of the solid salt, a two-phase system is obtained. Both liquid phases are recycled, allowing the design of a continuous process, which could be exploited industrially. The phase diagram of the system water-Na2SO4-PEG 3350 at 28 degrees C was used. Several process alternatives are proposed and their economic potential is discussed. The process steps needed to produce sodium sulphate crystals include mixing, crystallisation, settling and, optionally, evaporation of water. The yield of sodium sulphate increases dramatically if an evaporation step is used.

Crystallization↗
PubMed2000

Purification of soybean peroxidase (Glycine max) by metal affinity partitioning in aqueous two-phase systems.

Combining two concepts in downstream processing, this work investigates the partitioning of a crude soybean peroxidase (Glycine max) in an aqueous two-phase system by metal affinity. A liquid-liquid extraction process using metal ligands was developed in two steps with the aim of purifying the enzyme peroxidase. PEG 4000 was activated using thionyl chloride, covalently linked to iminodiacetic acid (IDA), and the specific metal ligand Cu2+ was attached to the PEG 4000-IDA. In the first step, the system was composed of 14% (w/w) PEG 4000-IDA-Cu2+ and 8% (w/w) Na2SO4, and the peroxidase partitioned mainly to the top phase (K = 24). In the second step, a system formed by 14% PEG 4000 and 10% phosphate was used to revert the value of the partition coefficient of peroxidase to the bottom salt-rich phase (K = 0.05), thereby achieving a recovery of 64% of the purified enzyme.

Chromatography, Affinity↗