Solutions Of Calcium Salts Research Articles

Some basic psychophysics of calcium salt solutions.

Detection thresholds and the taste qualities of suprathreshold concentrations of calcium salt solutions were assessed. Average taste detection thresholds for calcium chloride (CaCl2), lactate (CaLa), hydroxide, phosphate and gluconate ranged between 8 and 50 mM, with no reliable differences among the various salts. Between-subject variability ranged over four orders of magnitude and reliability coefficients for repeated detection threshold tests of CaCl2 averaged r = 0.52. In an odor detection test, subjects could reliably discriminate 100 but not 1 mM CaCl2 and CaLa from water. The taste of suprathreshold concentrations (1-100 mM) of CaCl2 and CaLa was considered unpleasant. At 1 mM, CaCl2 solution was rated as 35% bitter, 32% sour, 29% sweet and 4% salty. At higher concentrations the sweet component diminished and the salty component increased, so that 100 mM CaCl2 was rated as 44% bitter, 20% sour, 1% sweet and 35% salty. CaLa solutions were considered to be significantly less bitter and marginally more sour than equimolar CaCl2 solutions. Thus, the taste of calcium varied with both the form and concentration of salt tested, but included both sour and bitter components. Saltiness was identified only in high (> or = 32 mM) concentrations of CaCl2, and thus was not necessarily a component of calcium taste.

Effects of surface treatment on cation exchange properties of Australian brown coals

The cation exchange properties of Australian brown coals were investigated aiming at clarifying the influence of surface treatments. Dry heat treated (100–300°C, 2 h) and hydrothermally treated (130–300°C, 1 h) samples were used. Ion exchange experiments were performed by soaking coals in the solutions of calcium, magnesium, nickel, zinc and iron salts at 500–10 000 ppm in metal element, varying the initial pH by the addition of ammonia or hydrochloric acid. Extent of cation exchange (ECE) increased with increasing pH of solution. The decreases in ECEs for the dry heat treated and hydrothermally treated coals with increasing temperature were different from the decreases in the amount of carboxyl groups measured by titration method or infrared absorption spectroscopy. Further, the ECEs decreased by heat treatments were found to recover by the addition of ethanol to a certain extent. It was concluded that the main factor determining ECE on brown coals is a cation's accessibility to carboxyl groups which varies significantly with the pH of solution.

THE COMPARATIVE EFFECTIVENESS OF DISPERSANTS IN FRESH AND LOW SALINITY WATERS

ABSTRACT Four marine dispersant concentrates and two freshwater dispersant concentrates were tested in the laboratory for effectiveness in zero to average salinity using two different test oils. The data show that the comparative laboratory effectiveness for all the dispersants tested is lower at zero salinity, but that the variation in effectiveness as the salinity increases is different for each dispersant. Another part of the study compares the effectiveness of one marine dispersant and two freshwater dispersants in different electrolyte solutions. It is shown that effectiveness behavior in calcium and magnesium salt solutions is markedly different from that in sodium salt solutions. The results suggest that any future test protocol for dispersant effectiveness in fresh waters should take into account the detailed composition of the water in question.

The He(I) photoelectron spectra of aqueous solutions of calcium salts

The He(I) photoelectron spectra of the surfaces of liquid aqueous solutions of calcium chloride, bromide, iodide and nitrate at −10 to 15°C are reported. Values of vertical ionisation energies (eV±0.3) are: water (lone pair) = 11.2, Cl −( 2P) = 10.0, Br −( 2P) = 9.0, I −( 2P 3 2 ) = 7.8, I −( 2P 1 2 ) = 8.6, NO − 3 = 10 (shoulder).

Crystallization of calcium hydroxide from aqueous solution: I. Preliminary study

Calcium hydroxide was precipitated from seeded aqueous solutions of calcium salts and sodium or potassium hydroxide. The crystallization process was followed using the constant composition method over an appropriate range of supersaturations (σ = 0.2-0.4). The order of the growth was found to be between 2.3 and 3.3 for precipitations from 0.1M to 0.3M NaCl solutions and for seeds of three sizes.

Calcium Fortification of Soy Milk with Calcium‐Lecithin Liposome System

ABSTRACTCalcium ion was enveloped with a membrane system before addition to soy protein to prevent soy protein from being coagulated and precipitated by calcium ion. Soy lecithin was first sonicated in calcium salt solution to envelop the calcium ion with a liposomal structure composed of lecithin. Then, the calcium‐lecithin liposomes were added to soy protein solution. Precipitation and coagulation were not observed in this soy protein‐lecithin liposome system containing 60 mM Ca2+. By this method, it was possible to prepare calcium fortified soy milk containing more calcium (120 mg/100g) than in cow's milk. These results suggest that this calcium‐lecithin liposome system is useful for calcium fortification of soy milk.

Binding of calcium ions to 2,3-dicarboxy derivatives of starch and amylose

A series of 2,3-dicarboxy derivatives of oxidation degree DO(d.c.) 0.13 to 0.90 was prepared by a two-stage oxidation of corn starch and amylose. The activity coefficient γCa2+ of calcium counterions was estimated in solutions of calcium salts of these carboxy derivatives in a 3.00 mmol (COOCa0.5)l-1 concentration by a metallchromic indicator (tetramethylmurexide) method. A loss of electrostatic free enthalpy, Δ(Gel/N)KCa, due to the exchange of Ca2+ → 2K+ cations was determined by potentiometric titrations of the investigated polyacids and pectinic acids of various linear charge density of the macromolecule employing potassium and calcium hydroxides. 2,3-Dicarboxy derivatives of starch and amylose show a considerably strong binding of calcium ions even at low oxidation degree of the starting polysaccharides in contrast to solutions of the corresponding pectinates and carboxymethyl derivatives of cellulose and amylose. The strong bond of calcium ions to 2,3-dicarboxy derivatives of starch and amylose is ascribed to a favourable spatial arrangement of two neighbouring carboxyl groups at C(2) and C(3) of the oxidized D-glucose units due to a flexibility of the macromolecule chain at sites of the pyrane ring cleavage.

Ion-dependent Viscosity of Holothurian Body Wall and its Implications for the Functional Morphology of Echinoderms

ABSTRACT Dermis from the holothurian Thyone inermis was subjected to constant load and its rate of plastic deformation (creep) was used to calculate tissue viscosity. During these tests the material was bathed in distilled water, sea water, or solutions of sodium, potassium, calcium, and magnesium salts in various combinations. Distilled water caused a threefold increase in viscosity which was reversed by sea water. Sodium and potassium decreased viscosity, while calcium and magnesium in combination with sodium increased it. Ionic cross-links shielded by monovalent ions but facilitated by divalent cations are proposed to explain this behaviour, and the relationship between this and other anomalies of echinoderm connective tissue physiology is discussed.

The in vitro effect of boar semen on the contractility of rat uteri

Contradictory reports in the literature provoked the investigation of a possible oxytocic effect of boar semen on in vitro rat uterus preparations. When fresh boar seminal plasma (SP), dialyzed seminal plasma (DSP) or a filtrate of acetone-extracted seminal plasma (AE) were added to uterine preparations, both the frequency and force of spontaneous contractile activity tended to be depressed. When the uterine preparations were primed with oxytocin (1.6 USP units/100 ml bathing solution), treatment with SP and AE resulted in an increased frequency of contraction but no increase in force. DSP increased neither the frequency nor force of contractions. A solution of salts and organic compounds that approximated the small molecular or dialyzable components of boar semen (“synthetic boar seminal plasma” or BS) affected contractility in a manner similar to SP and AE. When the rat uterus was bathed in a low calcium physiological salt solution, none of the seminal treatments (SP, DSP, AE, or BS) were capable of initiating a contraction. Further, the force of carbachol-induced contractions in these uterine preparations was markedly depressed by these seminal treatments. In contrast, treatment with oxytocin nearly doubled the contractile force. The depressant effect of SP, DSP and AE on both spontaneous and carbachol-induced contractions appeared to be irreversible. Mineral analysis of SP, DSP, AE, BS and the low calcium salt solution showed the SP, AE and BS contained amounts of Ca 2+ and Mg 2+ which could have altered the uterine contractility. In addition, a non-dial-yzable factor in SP appeared to have a similar effect.

Intramolecular binding of calcium ions to L-guluronan and D-galacturonan

The values of activity coefficients γCa2+, determined earlier in solutions of calcium oligoguluronates and oligogalacturonates of various polymerization degree n, were interpreted. Values γCa2+ corresponding to an intramolecular Ca2+ bond to a polymeric chain of L-guluronan and D-galacturonan were obtained by extrapolation of functions γCa2+ = f(1/n) and γCa2+ = f((n-2)/n) to lim n → ##h. The γCa2+ values were compared with those determined in solutions of calcium salts of O-acetyl derivatives of pectic acid and D-mannuronan. In molecular disperse solutions the Ca2+ ions are bound to L-guluronan and D-galacturonan by an electrostatic bond. The course of the above-mentioned functions leads to the conclusion that both terminal uronic acid units in polyuronates under study bind Ca2+ ions less firmly than do the inner units in the macromolecule chain. The linear course of the function γCa2+ = f((n-2)/n) for L-guluronan proves the additivity of contribution of the terminal and inner uronic acid units to the total activity of Ca2+ counterions bound to L-guluronan.

Osmotic coefficients of aqueous polyelectrolyte solutions at low concentrations, 3. Dependence on macroion molecular weight

AbstractEight sodium salts of polystyrenesulfonic acid (poly[1‐(sulfophenyl)ethylene]) of different molecular weights were prepared similarly and purified in the same way. Their aqueous solutions were thus chemically equivalent, and differed only in their molecular weights, which were determined viscosimetrically.The osmotic coefficients (Φ) of the acid and its sodium, thallium, calcium and cadmium salt solutions were measured by a membrane osmometer for counterion molalities mc = 10−2 to 5·10−4mol/kg, at 25°C. In the same concentration range, the activity coefficients of hydrogen counterions (γH) of acid solutions were calculated from electromotive force measurements and the osmotic coefficients of the acid solutions were determined by the cryoscopic method for two different molecular weights. The values obtained are presented graphically as functions of the measured average molecular weight for mc = 10−3 and 10−2 mol/kg and are in good mutual agreement within experimental error.This agreement of results could be assumed to verify experimentally that the colligative properties of polystyrene‐sulfonate polyelectrolytes at low concentrations are dependent on the molecular weight of the polyion.The obtained results together with some literature data, allow us to evaluate very approximately the activity coefficients of monovalent counterions (γc) for mc = 10−2 mol/kg as a function of the degree of polymerization (n) of linear oligoions or polyions, for values of n up to 104.

Analysis of mouse oogenesis in vitro. Oocyte isolation and the utilization of exogenous energy sources by growing oocytes.

A method is described for the dissociation of mouse ovaries and the isolation of oocytes free of somatic cells by agitating pieces of ovary in collagenase and deoxyribonuclease in a calcium and magnesium free salt solution. This method yielded about 50% of the growing oocytes from immature mice. The utilization of exogenously administered 14C-labelled energy sources by oocytes in various growth stages was determined by measurement of evolved 14CO2. Little or no evolution of 14CO2 was detected from oocytes of any size incubated in 14C-glucose, lactate or succinate. The production of 14CO2 from 14C-pyruvate increased logarithmically when plotted against increasing oocyte volume with a plateau occurring after occytes reached a volume of 65,500 mum3 (50 mum diameter). Thus, the pattern of energy metabolism for oocyte maturation and early egg cleavage, wherein glucose and lactate are not utilized as efficiently as pyruvate, has been established by the earliest stages of oocyte growth.

Isotopieeffekte in der Grenzschicht anorganischer Lösungen / Isotope Effects at the Surface of Inorganic Solutions

Isotope effects were investigated at the surface of aqueous lithium and calcium salt solutions. The dependence on the temperature in the gas phase was determined. The surfaces of the solutions were isolated by spray experiments. In the case of calcium salt solutions an enrichment of the lighter isotope 40Ca in relation to the heavier isotopes 44Ca and 48Ca was found at the solution surface. The experiments with lithium fluoride and lithium iodide gave inverse isotope effects. The calcium isotope effect could be qualitatively explained by the Gibbs theorem. The isotope separation of lithium possibly can be referred to the more covalent bonding character than the ionic one of lithium compounds at the solution surface.

Structure formation in solutions of zinc and calcium salts of the copolymer of styrene and methacrylic acid

Viscosimetric and dynamic birefringence studies were made of the behaviour of Zn and Ca ionomers in DMF and bromoform with DMF additions. It was found that solutions of the zinc salts are molecular solutions, whereas macromolecules of the Ca ionomers form rod-like associates with a high degree of order in solutions.

The role of calcium, boron and some divalent ions in leaf tipburn of strawberry

Strawberry leaf tipburn occurs commonly in some cultivars in Britain during the summer outdoors, although usually only mildly. Outbreaks are occasionally severe in glasshouses. The damage arises at the time of leaf emergence, but is most evident after leaf expansion. Although the disorder can be induced by deficiencies of boron or calcium in the rooting medium, it also occurs where these elements are freely supplied in nutrient solutions. Where neither calcium nor boron were deficient, drops of aqueous solutions of calcium salts (but not of boric acid) applied to buds and emerging leaves greatly reduced or prevented tipburn. Drops containing manganese, magnesium or strontium salts also reduced tipburn, while drops containing oxalate or citrate induced it. The addition of small amounts of EDTA to the drops decreased the effectiveness of the manganese, magnesium and, to a lesser extent, strontium salts, but not that of calcium nitrate. The evidence suggests that tipburn is caused by a localised shortage of calcium occurring just before and during leaf emergence, resulting either from a deficiency of calcium at the roots or, more frequently, from an inadequate rate of uptake or transport of calcium.

Nuclear Magnetic Resonance Studies of 43Ca

The ratio of the Larmor frequencies of 43Ca and 37Cl has been measured and a magnetic moment for 43Ca of μ(43Ca2+ in D2O) = -1.315645 (7) μN; has been calculated. 43Ca chemical shifts have been determined in aqueous calcium salt solutions with 43Ca in natural abundance, also at low concentrations. The latter result is interesting for 43Ca studies in biological systems.

Calcium uptake by mitochondria from locust flight muscle.

1 It has been found that locust flight muscle mitochondria will accumulate calcium ions (in the presence of phosphate) rapidly and stoichiometrically from a sucrose or Tris-Cl medium, but only slowly from a potassium chloride medium. 2 The mitochondria are capable of accumulating small amounts of calcium ions (100 ng ions/mg protein) in the absence of any permeant anions. Acetate will not support massive accumulation. 3 Calcium uptake is blocked by low concentrations of praeseodymium ions. 4 Passive swelling experiments in solutions of calcium salts indicate that the mechanism of calcium ion entry into the mitochondria is similar to that observed for rat liver mitochondria. 5 The mitochondria were found to be very permeable to the anions chloride and isethionate.

Increased AutoAnalyzer Dialysis of Calcium and Magnesium in Presence of Protein

Abstract We have studied calcium and magnesium determination with the AutoAnalyzer, using dialysis, and measurement by atomic absorption spectrophotometry. The fraction of calcium and magnesium that dialyzes is proportional to the protein content of the sample; therefore an error is introduced when aqueous solutions of calcium or magnesium salts are used as standards. Apparently, the presence of proteins causes increased dialysis of Ca+2 and Mg+2.

The corrosion of mild steel in boiling salt solutions

The corrosion of mild steel in boiling solutions of the chlorides and sulphates of sodium, magnesium, and calcium has been examined. The rate and type of attack are found to be dependent on the type of salt, its concentration, and the period of test. The type of attack varies from predominantly pitting in pure water to even etching in strong magnesium and calcium salt solutions. Phases present in the corrosion product include a cubic oxide of variable composition usually associated with “green rust”, ferric oxides with a crystal structure similar to that of haematite, α-Fe 2O 3, and goethite, α-FeOOH.

The infrared determination of the composition of stearic acid multilayers deposited from salt substrata of varying pH

Infrared techniques were used to determine the effect of pH on the composition of stearic acid films on substrates containing dilute solutions of lead, copper, aluminum, calcium, barium, sodium, and quaternary ammonium salts. It was found that the pH region at which interaction of salts with the film occurs is characteristic for the particular salt and narrower than previously generally reported.