Release Of KCl Research Articles

Behaviour of gaseous chlorine and alkali metals during biomass thermal utilisation

The behaviour of gaseous chlorine and alkali metals of three sorts of biomass (Danish straw, Swedish wood, and sewage sludge) in combustion or gasification is investigated by the chemical equilibrium calculating tool. The ranges of temperature, air-to-fuel ratio, and pressure are varied widely in the calculations ( T=400–1800 K, λ=0–1.8, and P=0.1–2.0 MPa). Results show that the air excess coefficient only has less significant influence on the release of gaseous chlorine and potassium or sodium during combustion. However, in biomass gasification, the influence of the air excess coefficient is very significant. Increasing air excess coefficient enhances the release of HCl(g), KOH(g), or NaOH(g) as well as it reduces the formation of KCl(g), NaCl(g), K(g), or Na(g). In biomass combustion or straw and sludge gasification, increasing pressure enhances the release of HCl(g) and reduces the amount of KCl(g), NaCl(g), KCl(g), or NaOH(g) at high temperatures. However, during wood gasification, the pressure enhances the formation of KOH(g) and KCl(g) and reduces the release of K(g) and HCl(g) at high temperatures. During wood and sewage sludge pyrolysis, nitrogen addition enhances the formation of KCN(g) and NaCN(g) and reduces the release of K(g) and Na(g). Kaolin addition in straw combustion may enhance the formation of potassium aluminosilicate in ash and significantly reduces the release of KCl(g) and KOH(g) and increases the formation of HCl(g).

Development of new composites materials, carriers of active agents, from biodegradable polymers and wood

This work consists in the preparation of a biodegradable system starting from wood and polymer; this system being a support for the release of active agents. These starting materials used are poly(ε-caprolactone) (PCL), wood, the active agent being KCl. Initially the influence of water, wood and KCl on the reaction of polymerisation is studied. Two kinds of release systems are carried out: wood samples impregnated with KCl and/or PCL and blends of PCL, wood and KCl. Lastly, the release of KCl from these systems is studied in water. To cite this article: L. Mortain et al., C. R. Chimie 7 (2004) .

Effect of potassium chloride and cationic drug on swelling, erosion and release from κ-carrageenan matrices

The basic objective of this work was to study the effect of model cationic drug metformin HCl on swelling and erosion and, in turn, the release of KCl and drug itself, from the kappa-carrageenan matrices. Water uptake by the matrix up to 2 hours was found to increase with KCl concentration from the plain matrix. Erosion was not affected by concentration of KCl. Incorporation of drug favors water uptake, but in presence of KCl it was found to be reduced. Drug-containing matrices have shown higher release of KCl as compared with plain batches. Drug release was retarded as KCl concentration increased up to 5%, above which the reduced cohesivity of the matrix caused increase in drug release.

Dielectric analysis of PMMA microcapsules containing an aqueous KCl solution to derive a distribution function of the release rate of KCl

Release of KCl from a batch of PMMA microcapsules containing an aqueous 3 mM KCl solution was studied with the following two methods: 1) dielectric measurements of suspensions of the microcapsules in distilled water. The electrical conductivity of capsule interior was estimated with this method. 2) Measurements of the conductivity of suspending medium of the microcapsule suspensions. These two kinds of experiments provided us with information about the amount of KCl remaining in the capsules and that diffused outside. Results of these experiments showed that the microcapsules varied in their release rate of KCl. A distribution function of the release rates was derived from the results of the dielectric measurements. That distribution function was successful in explaining the results of the measurements of the conductivity of suspending medium. Furrther examination revealed that the release rate increased with the increase in the thickness of capsule wall.

Use of modified ethylcellulose lattices for microporous coating of osmotic tablets.

Commercially available lattices are often used to coat nonpareils or beads. Drug release occurs via diffusion through the polymer coating. Adequate release rates may be achieved with small particles because the surface area is large. However, tablets coated with unmodified lattices have exceedingly slow release rates. Therefore, a pore-forming agent, urea, was added to a commercially available ethyl cellulose latex, Aquacoat, to increase the release rate of drugs from coated osmotic tablets. Modified lattices were used to coat KCl and diltiazem.HCl tablets. Release of KCl and diltiazem into water or buffer solutions was determined in a standard U.S.P. dissolution apparatus. Rates varying from 1 to 100% release in 12 hr were obtained by varying the coating thickness, pore-former level, and plasticizer type and concentration. Scanning electron microscopy (SEM) showed that the urea was eluted from the coat in aqueous solution leaving a porous coating. Coat burst strengths were dependent on the coat thickness and the concentrations of pore former and plasticizer. Hence, modified lattices hold potential for use as coatings for controlled release osmotic formulations.

Volume regulation in glutathione-treated brook trout (Salvelinus fontinalis) erythrocytes

Brook trout erythrocytes that were washed with and suspended in Ringer's solution with reduced glutathione (1.0 mM) maintained steady state cell volume for up to 24h, while those without the thiol-protective agent steadily shrank. Changes in cell volume (measured as packed cell volume, PCV) were evoked by acidic media (Ringer's at pH 6.8), hypoosmotic solutions (or both) and intracellular K(+) and Cl(-) concentrations were monitored over 4h. Acid-swollen cells failed to volume regulate or release K(+) but had significantly elevated intracellular Cl(-) Osmotically-swollen cells at pH 7.8 but not at pH 6.8 underwent regulatory volume decrease (RVD) and returned to initial levels in 2h, accompanied by release of K(+) and Cl(-) In contrast, osmotically-shrunken cells did not show regulatory volume increase. The regulatory volume decrease and concomitant K(+) release were dependent on Cl(-) implying a direct or indirect coupling of K(+) to Cl(-) transport in volume regulation. RVD was partially blocked by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS, 0.1 mM), an anion exchange blocker, but was unaffected by amiloride (1.0 mM) which blocks Na(+)/H(+) exchange. Amiloride and DIDS prevented the swelling response to low pH but had no effect on control cells, suggesting involvement of Na(+)/H(+) and Cl(-)/HCO3 (-) exchanges in acid-induced cell swelling. Quinine (1.0 mM) a known blocker of K(+) channels, exacerbated the osmotically-induced swelling but had little effect on the subsequent RVD and release of KCl. The results suggest that low extracellular pH inhibits neutral C(-)-dependent K(+) release and the resultant regulatory volume decrease in osmotically-swollen cells.

Near constant release of KCl from an inwardly releasing matrix tablet

The release behavior from inwardly releasing KCl tablets is investigated and compared with theory, which predicts almost linear release with time, and with the release from commercially available tablets (KCl Durules ® and Kalipor ®). The tablets were produced by taking the commercial products, coating them with a water and KCl impermeable film, and, finally, drilling a central hole through each tablet. A one-parameter (the diffusion constant of KCl in the tablet) fit of the release according to theory to the experimental curves shows fairly good agreement. Moreover, the release rate is approximately proportional to the radius of the drilled hole. It is shown that in order to extend the release time, the tablet with a supporting matrix (KCl Durules) is advantageous over a tablet with an almost pure KCl core (Kalipor).

Spontaneous reversal of polarity of the voltage across LLC-PK1 renal epithelial cell sheets.

While sterilely monitoring transepithelial voltage (potential difference) across LLC-PK cell sheets over a 24-hr period, we noted that the apical-negative, transepithelial voltage, a key property of the LLC-PK1 renal epithelial cell line, reverses polarity to become apical-positive. This spontaneous change of polarity of electrical potential difference (PD) across LLC-PK1 cell sheets cultured on permeable filters was observed to occur approximately 12 hr after refeeding. Unlike the apical (luminal)-negative PD, the apical-positive PD was insensitive to phlorizin and ouabain. Both were insensitive to the diuretics amiloride, furosemide, and 4-acetamido-4-isothiocynato-stilbene-2,2-disulfonic acid (SITS). A pH gradient existed across apical-positive cell sheets (apical medium more acidic by 0.3 units) but an osmotic gradient did not. Unlike the temperature-sensitive apical-negative PD, the apical positive PD was unaffected by brief exposure to 4 degrees C temperature. Junctional disruptive agents such as the tumor promotor, TPA, dissipated both types of PD with similar time courses. The formation of the apical-positive PD correlated in time with apical glucose levels falling below the reported Km of the Na+-sugar contransporter. A high glycolytic rate per se may not be essential for this PD polarity reversal since the reversal could occur in glucose-free medium with a normal time course and magnitude. The lysis with time of floating cells with consequent release of KCl into the apical compartment was also considered as a possible cause of the polarity reversal, but the turnover of even 2 X 10(6) cells in 12 hr was found not to raise apical KCl sufficiently to produce the polarity shift. Although a significant K+ gradient did not exist across cell sheets with apical-positive PD values, a sizable gradient of Cl- did exist, directed apical to basolateral. This gradient, coupled with anion-selective tight junctions, should contribute to the observed apical positive voltage. The voltage polarity shift seen in these cell cultures with time is not unlike the polarity shift occurring in the renal proximal convoluted tubule, with distance from the glomerulus.

Release of stored energy of X‐irradiated KCl and CsBr

AbstractThe energy release of KCl and CsBr single crystals is measured after X‐irradiation at 10 K. Release maxima are found at 22, 28, and 36 K (KCl), and at 24 K (CsBr). The energy release is correlated with the annealing of irradiation‐induced Frenkel pairs by comparison with the results of optical absorption measurements. Below 50 K the release of stored energy is mainly due to the recombination of α + I Frenkel pairs. A value of 5 eV per recombination is found as an upper limit for the α + I Frenkel pair in KCl.