Cesium Chloride Solution Research Articles

Apparent molar volumes and heat capacities of aqueous lithium chloride, rubidium chloride, and cesium chloride at temperatures from (278.15 to 393.15) K at the pressure 0.35 MPa

Apparent molar volumes V φ and apparent molar heat capacities C p, φ were determined for aqueous solutions of lithium chloride, rubidium chloride, and cesium chloride at molalities m=(0.02 to 1.0) mol · kg −1, and at the pressure p=0.35 MPa. Density measurements obtained with a vibrating-tube densimeter at temperatures T=(278.15 to 368.15) K were used to calculate V φ values, and heat capacity measurements obtained with a twin fixed-cell, differential-output, power-compensation, temperature-scanning calorimeter at temperatures T=(278.15 to 393.15) K were used to calculate C p, φ values. Our results were fitted to functions of m and T.

Structure of Aqueous Electrolyte Solutions by X-ray Diffraction

Cadmium nitrate and cesium chloride solutions were studied in a wide concentration range by the X-ray diffraction method. The structure of aqueous solutions of the electrolytes is similar to the structure of solid phases that crystallize from them.

The enthalpy and entropy interaction parameters of cesium chloride with saccharide ( d-glucose, d-galactose, d-xylose and d-arabinose) in water at [formula omitted

The mixing enthalpies of aqueous cesium chloride solutions with aqueous monosaccharide ( d-glucose, d-galactose, d-xylose and d-arabinose) solutions, and the dilution enthalpies of cesium chloride solutions and these saccharide solutions in pure water have been measured at T=298.15 K to obtain the transfer enthalpies of cesium chloride from pure water to aqueous saccharide solutions. The enthalpy and entropy interaction parameters of cesium chloride with saccharides in water have been evaluated and discussed in terms of the electrostatic interaction, structure interaction, and the stereochemistry of saccharide to provide some information for the interaction of (solute + solute) and (solute + solvent) in (cesium chloride + saccharide + water).

Solubility of cesium chloride in water under high pressures

The solubility ( m sat) of cesium chloride (CsCl) in water was measured in the pressure and temperature ranges, 0.10–400 MPa and 273–313 K, respectively. The following function was fitted to the results: m sat (mol kg −1)=11.000−8.80×10 −3 p+3.3×10 −6 p 2+(0.0675−4.167×10 −5 p)( T−293.15)−0.81×10 −4( T−293.15) 2. The standard deviation is 0.022 mol kg −1. This level of precision in solubility is almost an order of magnitude better than the literature data for the same system at the atmospheric pressure. This improvement in reproducibility is due in part to a better design of the inside of the pressure vessel used for the present study. The pressure and the temperature coefficients of the solubility were thermodynamically estimated using relevant data of the solute and the solution in literature. To supplement the volume data, we also measured the density of aqueous solution of cesium chloride at high concentrations. The coefficients thus calculated were the same within experimental error with those derived from our data, the equation shown above. It proves our solubility measurement under high pressure reliable.

Impact of purification procedures on the viability and infectivity of Cryptosporidium parvum oocysts

The development of new technologies for Cryptosporidium oocyst detection as well as inactivation and removal is at the forefront of research objectives for the drinking and wastewater industries. One of the major issues associated with testing new technology is determining oocyst viability and infectivity before and after treatment. Because oocysts must be isolated from feces, preparation and pretreatment procedures may affect oocyst infectivity and potentially confound results obtained during survival and disinfection studies. The principal objective of this study was to evaluate the effects of preparation and pretreatment on C. parvum oocyst (Ames, Iowa isolate) infectivity in an in vitro cell culture assay. In vitro excystation, sporozoite yield, and vital dye exclusion using DAPI and PI were used to test viability. A matrix of purification procedures using two defatting agents (ethyl acetate and ethyl ether), cesium chloride (CsCl) and Sheather's solution was evaluated. Effects of immuno-magnetic separation (IMS) and bleach treatment were also assessed. Oocysts purified using CsCl alone showed the most consistent infection from experiment to experiment, compared to preparations that were purified using a defatting agent. Defatting agents, IMS and bleach treatment had no detrimental effects on oocyst infectivity, however, considerable variability between oocyst lots was observed. This study determined that both purification processes and age affect oocyst infectivity.

EFFECT OF PRESSURE ON THE VISCOSITY B COEFFICIENT OF CESIUM CHLORIDE IN WATER

Viscosity of aqueous cesium chloride (CsCl) solution was measured in the ranges of 0.1-5.0molkg-1 and 0.1-375MPa at 283.2 and 323.2K. The Jones-Dole B coefficient of CsCl increased with increasing pressure and then decreased passing over a maximum as well as previously observed one at 298.2K. The maximum B became more remarkable with decreasing temperature from 323.2K to 283.2K. These phenomena were compared with the dielectric friction theory supposing solvent water as a continuum fluid. Inconsistency of the theory at low pressure suggested an existence of any structure in water. Pressure dependence of B is ascribed to a balance between the water structure and the dielectric friction effect.

Effect of pressure on the viscosity of aqueous cesium chloride solution at 25°C

Viscosity of aqueous cesium chloride (CsCl) solution was measured in the range of 0.1–5.0 mol kg −1 and 0.1–375 MPa at 25 °C. The Jones-Dole B coefficient of CsCl was obtained from the concentration dependence of the viscosity. It is negative not only at atmospheric pressure but also at high pressure, having a maximum against pressure at about 160 MPa. Similar maximum of the B was observed for aqueous sodium chloride (NaCl) solution. The similarity is discussed in terms of the water structure and dielectric friction theory.

Diffusivity of Zinc Ions in Aqueous Alkali-Metal Chlorides

The tracer-diffusion coefficients of radioactive zinc ions in aqueous potassium chloride, cesium chloride, and lithium chloride solutions of concentration between 0.005 and 2.5 mol dm -3 are determined using an open-ended capillary technique with stirring. The theoretical tracer-diffusion coefficients of zinc ions in aqueous salt solutions are calculated using the Gosting-Harned equation and compared with the experimentally determined diffusion coefficients. The measured values of tracer-diffusion coefficients of zinc ions in the aqueous alkali-metal chloride solutions agree with the theoretically predicted values up to a concentration of about 0.05 mol dm -3 . At higher concentrations, the tracer-diffusion coefficient of zinc ions first increases and again decreases with concentration, giving rise to a maximum in the plot of the tracer-diffusion coefficient against the square root of the concentration. A qualitative explanation of the concentration dependence of the tracer-diffusion coefficient of zinc ions in concentrated solutions of the salts is attempted by taking into account the ion-ion and ion-water interactions

Supercritical toluene extraction of maceral concentrates obtained from Turkish coals

Five Turkish coals of rank varying from high volatile bituminous to sub-bituminous C were separated into four fractions by sequential sink-float treatment with cesium chloride solutions of different densities. Following the maceral analysis, each fraction was subjected to supercritical toluene extraction at 400°C and 100 atm. The extracts were separated into three fractions, namely preasphaltene, asphaltene and oil. Oil fractions were further separated into paraffinic, aromatic and polar sub-fractions. It is observed that SCG toluene extraction produces higher extract yields in lighter maceral concentrates when compared with those obtained from denser fractions. The average molecular weights of the extracts obtained from coals and from their corresponding maceral concentrates are all coal specific. The average molecular weights of the SCG extracts indicated that retrogressive reactions during SCG extractions are more prominent in low-rank coals. The oil fractions are dominating in the SCG toluene extracts and this is more prominent in the extracts obtained from sub-bituminous coals. The gaseous product formations during SCG extraction of the whole sub-bituminous coals are substantial but this is remarkably reduced during the SCG extraction of the corresponding maceral concentrates.

Adsorption of amino acids and glucose by sediments of Resurrection Bay, Alaska, USA: Functional group effects

The adsorption of amino acids and glucose was investigated in sediments from Resurrection Bay, Alaska. Adsorption of the basic amino acid lysine was greater than adsorption of glutamic acid, alanine, leucine, or glucose. Formaldehyde and heat treatments were used to separate adsorption from biological uptake, but can alter adsorption significantly; formaldehyde treatment, followed by a seawater rinse, was the most satisfactory. Much of the rapid amino acid adsorption by these sediments was due to the formation of ionic bonds, since adsorbed amino acids could be extracted using concentrated solutions of amino acid, cesium chloride, sodium citrate, ammonium chloride, or sodium acetate. However, most amino acid adsorption was not reversible by ion exchange solutions, indicating that additional processes or chemical reactions occur which result in irreversible binding to sediment. Consistent with literature reports of the negative surface charge of marine particulate matter, lysine (with a net positive charge) was adsorbed to the greatest extent and had the largest cation-exchangeable adsorption. However, negatively charged amino acid functional groups also influenced adsorption. Chemical modification of sediments with reagents reactive with aldehydes decreased lysine adsorption. This suggests that reactive functional groups of sediment organic matter contribute to adsorption, consistent with a melanoidintype reaction. An estimate of the rate of amino acid adsorption indicates that adsorption could produce a significant amount of the total refractory sediment organic nitrogen.

Development of a laboratory method to predict rapidly the availability of radiocaesium.

A simple extraction procedure has been developed to assess rapidly the probable extent of the transfer of radiocaesium into ruminant food products soon after a nuclear accident. The in vitro extractions were validated against true absorption measurements of different forms of radiocaesium in the sheep gut. Extractions were performed on a range of different radiocaesium sources. Some of these sources were artificial (ionic radiocaesium adsorbed onto bentonite, silica spheres and filter-papers) and others were environmentally contaminated [silt from the Ravenglass Estuary contaminated by effluent from British Nuclear Fuels Limited (BNFL) Sellafield, and upland grass and heather contaminated by Chernobyl fallout]. Laboratory experiments concentrated primarily on the use of simple inorganic extractants in competitive ion-exchange processes. Of the reagents used, 0.1 mol dm-3 stable caesium chloride solution was the most effective extractant. The proportion of radiocaesium extracted by 0.1 mol dm-3 caesium chloride correlated well with measurements of true absorption. Extracting radiocaesium using 0.1 mol dm-3 caesium chloride proved to be an inexpensive and rapid method of predicting the availability of radiocaesium for absorption in the ruminant gut, giving results within 24 h. Further extractions were carried out using cellulase/pepsin simulated digestions and ovine rumen fluid. Results suggested that the availability of radiocaesium from some inorganic sources may be underestimated using such techniques.

Interactions in clay/electrolyte systems

The sorption of cesium and cobalt on kaolinite and montmorillonite were followed by radiotracer method. The sorption of cesium can be described by a Freundlich isotherm. Cobalt sorption on clays equilibrated in cesium chloride solutions significantly differs for kaolinite and montmorillonite due to their differences in sites available for cation sorption and changes in solution chemistry.

Isolation of corneocyte envelopes from porcine epidermis.

Sheets of porcine stratum corneum were dispersed into individual corneocytes after 4 h in a solution consisting of 8 mM N,N-dimethyldodecylamine oxide and 2 mM sodium dodecylsulfate in phosphate-buffered isotonic saline, at 45 degrees C. With continued detergent treatment and moderate sonication, most of the cells lost their keratin contents and were then separated from the remaining intact cells by centrifugation in cesium chloride solution of density 1.280. Electron microscopy showed that the cell envelopes retained both the crosslinked protein envelope and its attached lipid envelope. The dry weight of envelopes was approximately 7% of the estimated dry weight of the original stratum corneum, while the corneocytes surviving intact also amounted to 7% of the starting weight. Mild alkaline hydrolysis of the corneocyte envelopes allowed the extraction of hydroxyceramides amounting to 10% of the dry weight of the envelopes. The procedure therefore provides isolated corneocyte envelopes suitable for studying both the protein and lipid components of this compound sheath.

Charged soot in low-pressure acetylene/oxygen flames

The relative volume fractions of positively and negatively charged soot particles were determined in flat, low-pressure, premixed acetylene/oxygen flames. For this purpose soot particles in a beam were separated according to their charge by an electric field. After deposition on a glass plate the respective relative amounts were determined by microdensitometry. The relative degree of soot ionization reached a maximum at heights of 50 to 70 mm above the burner. It was slightly larger in more strongly sooting flames. With increasing flame temperature there was more positively than negatively charged soot. Seeding of the flames with cesium chloride solution or pure water caused a reduction in the absolute amount of soot and in its relative degree of ionization. The only specific effect of the salt was to increase the negative over the positive soot ionization. The experimental method also allowed a mass analysis. Mass distributions of positively and negatively charged particles at the same height in the flame were nearly equal. Addition of CsCl solution reduced the size of the particles of either sign of charge in the same way. A partial-equilibrium model can simulate the relative volume fractions of charged soot up to their respective maxima in a satisfactory way, except for doubly charged particles. It was found that the particle diameter has a much stronger influence on the soot ionization than the temperature or the work function of the soot. The ratio of positively to negatively charged particles is controlled by the presence of negative molecular ions and positive metal ions.

Aliphatic substituents in place of thymine methyl promote zig-zag character of the poly(dA-dT)·poly(dA-dT) backbone

This work compared circular dichroism and phosphorus n.m.r. of poly(dA-dU)·poly(dA-dU), poly(dA-dT)·poly(dA-dT), poly(dA-ethyl 5dU)·poly(dA-ethyl 5dU), and poly(dA-butyl 5dU)·poly(dA-butyl 5dU) at low-salt and in concentrated caesium chloride and caesium fluoride solutions. It is demonstrated that growing bulk of the substituent increases the conformationl anomaly residing in the purine(3′–5′)pyrimidine steps while the backbone is less affected in the pyrimidine (3′–5′)purine steps. As the length of the substituent increases, conformation of the polynucleotides alters more dramatically at increasing concentrations of caesium cations. At high CsF concentrations, all the polynucleotides adopt a novel conformer which we call X-DNA and its formation is promoted by larger substituents. The X-DNA conformation of poly(dA-butyl 5dU)·poly(dA-butyl 5dU) gives two phosphorus n.m.r. resonances separated as much as in the case of the left-handed zig-zag Z-DNA double helix of poly(dG-dC)·poly(dG-dC) but X-DNA and Z-DNA differ qualitatively by an opposite dinucleotide repeat. Phosphorus n.m.r. spectra of poly(dA-dT)·poly(dA-dT) and poly(dA-butyl 5dU)-poly(dA-butyl 5dU) differ quantitatively at high CsF concentrations, which may reflect conformational variability of the X-DNA backbone. Poly(dA-butyl 5dU)·poly(dA-butyl 5dU), but not poly(dA-ethyl 5dU)·poly(dA-ethyl 5dU) and the related polynucleotides with shorter substituents in position 5 of uracil, exhibits one more reversible transition at very high caesium fluoride concentrations. It is accompanied by polynucleotide associations and has a slow kinetics. This transition may involve one more radical change in the double helix architecture from X-DNA into another conformation.

Ethidium bromide: Destruction and decontamination of solutions

Ethidium bromide in water, TBE buffer, Mops buffer, and cesium chloride solution may be completely degraded by reaction with sodium nitrite and hypophosphorous acid. Only nonmutagenic reaction mixtures were produced. Destruction was >99.8% in all cases; the limit of detection was 0.5 μg ethidium bromide per milliliter of solution. Ethidium bromide also may be removed completely from the above solutions by using Amberlite XAD-16 resin. The limit of detection was 0.05 μg ethidium bromide per milliliter of solution (0.27 μg/ml when cesium chloride solution was used).

Brief closures of gramicidin A channels in lipid bilayer membranes

Brief closures, so called flickers, gramicidin A channels were observed for glycerol monooleate/n- decane membranes for cesium chloride and hydrochloric acid solutions. The flickers, similar in nature to the flickers observed for physiological channels, were of the order of 1 ms and the interval between flickers was of the order of 50 ms. The flicker-duration and interval between flickers both decrease with voltage. The field dependence of the flickers is consistent with the hypothesis that the membrane forms a dimple when accomodating a dimer in the membrane and that the monomers, on breaking up, are associated over displacements of the order of 2 nm. For similar measurements for glycerol monoleate/hexadecane membranes only rare occurrences of flickers were observed. It is suggested that the flicker phenomenon is governed by the physical and chemical properties of the membrane and the influence of membrane thickness and interfacial free energy is emphasized.

The estimation of virus density in isopycnic cesium chloride gradients

Methods for estimating the density of virus particles after isopycnic centrifugation in cesium chloride gradients were examined. If solutions were prepared in different buffers, the standard tables relating refractive index and density, based on solutions prepared in water, did not give consistent estimates even if corrections were made for the greater refractive indices of the buffers. Depending on the method and buffer used, estimates of the density of cricket paralysis virus, an insect picornavirus, differed by as much as 0.05 g/ml. However, consistent estimates were obtained if separate regression equations were derived to relate refractive index and density for each different buffer solution of cesium chloride. This has wider implications and could account for density differences or variations in estimates reported for many other viruses.

Isopycnic centrifugation of plant viruses in Nycodenz® density gradients

Isopycnic centrifugation of plant viruses in density gradients prepared from a new non-ionic medium (Nycodenz®) was investigated. Particle density of luteo-, tymo-, nepo-, cocksfoot mild mosaic, tobamo-, hordei-like, potex-and potyviruses in buffered solutions of Nycodenz® ranged between 1.23 and 1.28g/ml and did not strictly reflect their nucleic acid and protein composition. Isopycnic centrifugation of several partially purified viruses yielded preparations which were pure by electron microscopy and, when used as immunogens in rabbit or hen, gave antisera with low tilers of antibodies against host plant antigens, as required for enzyme immunoassays. A preparation of purified potato leafroll virus contained a single dominant protein corresponding to the viral coat protein. It is concluded that isopycnic centrifugation in Nycodenz® density gradients is particularly useful for the purification and analysis of plant viruses which are unstable in cesium chloride solutions, such as the luteoviruses, and preferable to zonal centrifugation in sucrose density gradients for the purification of rod-shaped multipartite viruses or viruses which aggregate.

Tje spherically averaged structures of cowpea mosaic virus components by X-ray solution scattering

The X-ray diffraction patterns of the four components of cowpea mosaic virus isolated from a cesium chloride gradient were measured, using film methods, to 30 Å resolution. Diffraction patterns were analyzed by fitting computed two-shell spherical models to the observed data. The fitting procedure was applied to data to 80 Å resolution to avoid the nonspherical contribution to the pattern observed at higher resolution. At pH 7.0 all four components displayed the same external spherically averaged radius of 140 ±2 Å. The lowest density component (top), which contains no RNA, was best modeled by an empty shell with an outer radius of 140 Å and an inner radius of 101 ± 3 Å. The middle component, containing 27% RNA by weight, was modeled with a uniform electron density sphere. The bottom upper and bottom lower components, which are biologically identical but display different buoyant densities in cesium chloride solutions, were analyzed independently. The bottom upper component was best modeled with a 101 Å inner (RNA containing) sphere of mean electron density 0.453 e −/Å 3 and a 101 to 140 Å outer (protein containing) shell of electron density 0.410 e −/Å 3. The bottom lower component was fit with the same model except that the RNA containing region displayed a mean electron density of 0.459 e −/A 3. The implications of the spherically averaged component structures for the protein structure, RNA and protein hydration, and cesium binding to RNA are discussed.