Упруго-пластические свойства ионообменников на основе сшитых полиэлектролитов

In this paper, a mathematical physics model is set up to study dielectric constant profile of aqueous solvent in ionic solution, to revise Brownian dynamics simulation in ionic solution by considering time-variant dielectric constant profile with change in ion positions, and to study the effect of high-intensity electric pulses on the profile. The validation of the model is confirmed with verification calculations. By means of the proposed model, dielectric constant profiles in calcium chloride and sodium chloride solutions and their response to pulses are simulated. Based on numerical results, dielectric constants of aqueous solvent spatially vary instead of being the same value in ionic solutions. And the profiles are variant with time due to ion motion in solutions. From the profiles, overall dielectric constant in calcium chloride solution is lower than that in sodium chloride solution. And overall dielectric constant decreases with increment of solution concentration. In addition, the results show that influence on the profiles depends on solution concentration and field intensity of the pulse. The profile in solutions with low concentration is more vulnerable to the pulse than that with high concentration. And overall dielectric constant decreases dramatically as field intensity increases. Those understandings provide basis for application of pulses in biomedical engineering at the molecular level. Meanwhile, pulse radiation provides a potential way to constrain water molecules at room temperature reflected by significantly reducing dielectric constant, and to lower absorption loss of electromagnetic field in millimeter and far infrared band.

The diffusion of chloride ions can cause corrosion of concrete buildings, thus reducing their service life. The diffusion of chloride ion in concrete is mainly carried out between the interfaces of different phases. In this article, Hamid model and Jennite model are used to represent C-S-H gel phase with different ratios of calcium to silicon (C/S), and Fe crystal is used to represent stainless steel phase. The diffusion behavior of chloride ion in calcium chloride (CaCl2) solution layer with a certain thickness, which is between gel phases, gel phase and stainless steel phase, was studied. A supercell molecular model containing upper and lower surface phases and CaCl2 solution in the middle was established. The effect of upper and lower surface type, the thickness of solution layer, and concentration of CaCl2 solution were investigated by molecular dynamics simulation. The results show that when the upper and lower surfaces are Fe and C-S-H crystals, respectively, the diffusion coefficient of chloride ion is one order of magnitude larger than that of both C-S-H crystals, where the diffusion coefficient of chloride ions decreases with the increase of C/S on the whole. The relative concentration distribution of calcium ion and chloride ion in the solution layer were analyzed, demonstrating that the surface of C-S-H crystals are negatively charged near the side of the solution and the diffusion of chloride ions is related to the number of charges; the diffusion coefficients of chloride ions increase with both the concentration and thickness of CaCl2 solution layer.

Bentonite is a critical component of geosynthetic clay liners (GCLs) because of its low hydraulic conductivity. However, bentonite can migrate within the GCL roll while transporting and installing the GCL. Thus, the bentonite mass per unit area (MPUA) in GCLs generally varies within the roll. Although information regarding the influence of MPUA on the hydraulic conductivity of GCLs to water is sufficient, the barrier performance of GCLs against leachates is limited. This study investigates the barrier performance of sodium (Na)-GCL under various MPUA conditions and different calcium chloride (CaCl2) solutions. Na-GCL with MPUAs of 3.0, 4.0, and 5.0 kg/m2 (Mb3, Mb4, and Mb5) were subjected to hydraulic conductivity tests with deionised water (DIW) and a calcium chloride solution. The effect of MPUA on the hydraulic conductivity of GCLs was negligible when DIW was used and was significant when the permeant was a calcium chloride solution. The hydraulic conductivity of Mb3 was above 1.0 × 10−9 m/s at all concentrations. In contrast, the hydraulic conductivity of Mb4 and Mb5 increased gradually when the permeant was 15 and 30 mM calcium chloride. Chemical analyses showed that when the cation exchange was complete, the bundle of fibres available on the GCLs controlled the hydraulic conductivity.

By actively changing the pH of the enema solution of calcium preparations, especially of calcium chloride, the influences of the varying pH of the enema solution on the absorption of calcium in the large intentine was investigated in the first place. When the reaction of the enema was shifted to the alkaline side with NaOH, the absorption of calcium chloride in the large intestine was evidently enhanced at pH 8.0. At pH 7.0 or pH 9.0, the absorption remained the same as in the control tests with the solution without adjustment of pH, and there was no enhancement of absorption note-dWhen the reaction of the enema was shifted to the acid side with acetic acid, lactic acid or hydrochloric acid, the absorption of calcium chloride in the large intestine was remarkably enhanced at pH 2.8 in all cases. Especially, when the reaction was adjusted with hydrochloric acid, the absorption was most distinctly enhanced, and all the rabbits used demonstrated intoxication symptoms and became fatal. As already reported by Hitomoto and Kato, the calcium content in the peritoneal fluid in such cases was found extremely increased. Previously, Kato reported a very interesting result that when calcium preparations combined with the mixture of glycocoll and glucose is administered as enema, the absorption of calcium chloride in the large intestine is greatly enhanced, and further, that calcium lactate and calcium sulfate, which are usually not absorbed from the large intestine, are also absorbed. Whereas, I confirmed that, when calcium sulfate solution is acidified to pH 2.8 with acetic acid, calcium sulfate is absorbed in the large intestine, though slower compared with calcium chloride, and the serum calcium content is somewhere about 24mg/dl even after 210 minutes. Adjustment of the reaction to pH 2.8-3.0 combined with ox bile does not particularly enhance the absorption compared with the above results, but when too much ox bile is combined, intoxication death caused by abnormal absorption of biliary acid and excess of calcium content in the serum is observed. In the case of oral administration, even doubled amount of calcium chloride solution of the case of enema (20cc. per kg. of 5% calcium chloride solution) generally increase the serum calcium content only slightly. Whereas, when ox bile is combined, the serum calcium content increases rapidly indicating the enhanced absorption of calcium in the small intestine. Differing from the case of enema, in the case of oral application, no particular enhancement of the absorption of calcium is observed even the reaction of calcium chloride solution is adjusted to pH 2.8 with acetic acid, lactic acid or hydrochloric acid. Further, when ox bile is combined with calcium chloride solution with adjusted pH, no particular difference is noted in the influence of bile from that in the case combined with the same solution without pH adjustment. Despite the fact that the absorption of calcium in the small intestine does not demonstrate any difference between that of calcium solution with adjusted pH or without pH adjustment combined with ox bile, the absorption of calcium administered in combination with ox bile induces much more rapid and distinct enhancement of calcium absorption compared with that of the application of calcium alone. Consequently, it became essential to know calcium absorption in the stomach. When calcium chloride solution was orally administered after the pylorus of stomach was ligatured, the fact, that the serum calcium content did not increase during the elapse of 210 minutes from the administration even in the combined application with ox bile, was confirmed. By the above fact, it is presumed that the rapid increase in serum calcium content in the case of combined application with ox bile may be induced by rapid transfer of calcium chloride solution from the stomach to the small intestine and enhancement of calcium absorption in the small intestine by ox bile.

The present study evaluated the effect of endovascular administration of calcium chloride to the carotid artery of swines, to create a model of arterial calcification. Fifteen Large White pigs were used for the study. Via endovascular treatment, carotid arteries were exposed during 9 min to either calcium chloride (experimental artery) or saline (control artery) with the use of the TAPAS catheter. Intravascular ultrasound (IVUS) imaging was obtained at baseline, postprocedure and at 30 days. Optical coherence tomography (OCT) imaging was obtained in vitro after carotids were harvested. Longitudinally cut parallel arterial segments were placed in a system of delicate clamps and underwent uniaxial strain test. All arteries underwent histopathological examination. Calcium chloride treated segments showed extensive circumferential parietal calcification evident on both IVUS and OCT. Reduction in minimal lumen area on IVUS was evident in experimental arteries both at 24 hr and 30 days postprocedure. Histopathologic assessment (Von Kossa stain) confirmed medial calcification with mild intimal thickening. Biomechanical testing showed treated segments to have smaller breaking strength and less elastic deformation than controls. We developed a nonexpensive, reproducible model of early carotid medial calcification in pigs. Our model has the potential to help the development of research to unravel mechanisms underlying arterial calcification, the use of current or new devices to treat calcified lesions as well as to serve as an option for training interventionalists on the use of such devices.

The effect of ammonium sulfate, ammonium chloride, potassium chloride, calcium chloride, aluminum chloride, and copper sulfate added in amounts corresponding to 0.2, 2, and 20 atm concentration on mineralization of soil nitrogen in three soils was measured over a 30‐day period. Significant increases were produced by the ammonium salts which were labeled with 15 N to allow distinction between added and soil nitrogen. In Aiken clay loam nitrogen mineralization was also increased by solutions of potassium chloride, calcium chloride, and aluminum chloride, but in Altamont clay loam and Mormon clay increases were not consistent. Copper sulfate depressed nitrogen mineralization in all soils. It was found that the quantity of organic nitrogen brought into solution was related to the concentration of the salt solution.

This article took the sodium sulfate and calcium chloride as the raw material and prepared calcium sulfate whiskers by hydrothermal method. The experimental results show that the calcium sulfate precursors are prepared by the reverse feed mode in which the sodium sulfate solution drop into the calcium chloride solution under the solution concentration 0.6 mol/L and the molar ratio of Na2SO4 to CaCl2 at 1:1.8. The precursors were placed in pH=6.12 hydrothermal environments and treated in the autoclave at 140 °C for 4 h to obtain the calcium sulfate whiskers having for the ratio of length to diameter at 97.5 and the better morphology.

Preparation and characterization of in-situ ionic cross-linked pectin films: II. Biodegradation and drug diffusion

This paper investigates the use of calcium alginate microcapsules to transport biomaterials for drug delivery. Rhodamine 6G dye was encapsulated in microcapsules for different formulations of the hydrogels using drop-on-demand printing. An experimental design was constructed to compare the effect of different concentrations of calcium chloride (M) and sodium alginate (% w/v) solutions in addition to the microcapsule diameter on the release kinetics profiles of the microcapsules. The results of these findings provide a basis to identify favorable sizes of microcapsules and concentrations of sodium alginate and calcium chloride solutions for controlled release behavior of microcapsules.

The purpose of this study was to evaluate the incompatibility of ceftriaxone sodium with calcium-containing products using the ionic product of precipitation, and the measurement of insoluble microparticles using a light obscuration particle counter. Appropriate volumes of 2% (w/v) calcium chloride solution were added to 0.4-2 mg/ml ceftriaxone isotonic sodium chloride solution, to make solutions with a final calcium ion concentration of 1.25 mmol/l. The solutions were gently agitated and stored at 37 degrees C for 24 h. The number of insoluble microparticles with a diameter less than 10 microm in the mixed sample solution, determined using a light obscuration particle counter, was increased when the ceftriaxone concentration was > or =0.8 mg/ml. The Saturation Index (defined as the ratio of the ionic product to the solubility product constant) of the prepared mixed solution was 1.1. A white precipitate could be observed visually when the ceftriaxone concentration of the sample solution was 7 mg/ml; the Saturation Index of the solution was 9.7. The effect of the calcium source on incompatibility with ceftriaxone sodium was also evaluated. The numbers of insoluble microparticles in sample solutions made by adding calcium chloride to the sample were significantly higher than those made by adding calcium gluconate. These results suggest that ceftriaxone should not be co-administered with calcium-containing products even if no precipitation is observed visually. There will still be insoluble microparticles caused by incompatibility in the sample solution when the Saturation Index of the solution is over 1.0.

Calcium and magnesium ions play important roles in many physicochemical processes. To facilitate the investigation of phenomena related to these ions that occur over large length and time scales, a coarse-grained force field (CGFF) is developed for MgCl2 and CaCl2 aqueous solutions. The ions are modeled by CG beads with characteristics of hydration shells. To accurately describe the nonideal behavior of the solutions, osmotic coefficients in a wide range of concentrations were used as guidance for parametrization. The osmotic coefficients were obtained from the chemical potential increments of water calculated using the Bennett acceptance ratio (BAR) method. The result CGFF accurately reproduces experimental osmotic coefficients, densities, surface tensions, and cation-anion separations of calcium chloride and magnesium chloride solutions at molalities up to 3.0 mol/kg. As a preliminary application, the force field is applied to simulate aggregations of sodium dodecyl sulfate (SDS) in calcium chloride solution, and the simulation results are consistent with experimental observations.

Development of an in situ soil binding agent

Preparation and in vitro evaluation of mucoadhesive properties of alginate/chitosan microparticles containing prednisolone

The aqueous solubility of benzene in the presence of calcium chloride at different concentrations was measured at 303.15 K. Also, experimental liquid−liquid equilibrium data were obtained at 303.15 K for the ternary system benzene + water + acetic acid as a function of calcium chloride concentration. The solubility of benzene in water is 1910 ppm at 303.15 K and decreases to 502 ppm with the addition of 20 mass % calcium chloride. The solubility data of benzene in calcium chloride solutions were correlated with the Setschenow equation, and the Setschenow constant, ks, is 0.33 ± 0.002. From the liquid−liquid equilibrium studies it is observed that the amount of acetic acid extracted to the organic phase increases with the amount of added calcium chloride. It is suggested that the salt effect should be explored further to develop or improve processes to treat waste streams contaminated with organic compounds.

Comparison of nano-calcium and calcium chloride spray on postharvest quality and cell wall enzymes activity in apple cv. Red Delicious