Surface Studies of Calcium Oxalate Dihydrate Single Crystals During Dissolution in the Presence of Stone-Formers\u27 Urine

Dissolution of calcium oxalate dihydrate (COD) single crystals was studied at different pH levels and in different dilutions of stone formers\u27 (SF) urine. The Fourier descriptors of the contour were determined during dissolution of COD using a quantitative morphological technique. The surface ruggedness of COD single crystals was determined from fractal analysis. The results obtained were compared with COD single crystals behavior in different dilutions of normal urine previously reported. The shape parameters and surface geometry of the dissolving COD crystals were significantly different in normal and SF urine. The data suggest that the shape descriptors and fractal geometry is likely to be a potential factor in identifying the urine of stone formers

Surface Studies of Calcium Oxalate Dihydrate Single Crystals During Dissolution in the Presence of Urine

Single crystals of Calcium Oxalate Dihydrate (COD) were grown from solution under controlled release of the reacting ions. Dissolution of COD was studied at different pH levels and in different dilutions of urine. The descriptors of the contour were determined during dissolution of COD using a quantitative morphological technique. The shape parameters and surface ruggedness were determined from Fourier and fractal analysis. The results obtained give quantitative information on the dissolution kinetics and the surface geometry of COD crystals in normal and diluted urine. Dissolution inhibition and morphological changes of COD crystals during dissolution were attributed to selective adsorption of urine non-ionic macromolecules on the crystal stepped surface. Surface etching of COD was found to depend on urine dilution and time of incubation. The data obtained suggest that the geometric structure of the surface is likely to be a potential factor in understanding crystal aggregation in stone formation

Evolution of spherical overdensity in Chaplygin gas model

Even though many scalar field models of dark energy have been considered in the literature, there is another interesting class of dark energy models involving a fluid known as a Chaplygin gas. In addition to describing the dark energy, both scalar-tensor model and the Chaplygin gas model are suitable candidates for explaining the spherical cosmological collapse. One of the most well-known scalar field models is the quintessence model, which was first introduced to explain an accelerating expanding universe. Using a special form of the quintessence model that is equivalent to Chaplygin gas, we describe evolution of a spherical collapse. We study the cosmological properties of the quintessence field with a special potential. In addition to the quintessence model, that can be converted into a Chaplygin gas model in a particular case, we claim that the fixed-potential tachyonic model is equivalent to the Chaplygin gas model. In this work, we obtain the spherical collapse parameters: the virialized over density parameters, radius, the energy density at the turnaround moment, etc. We compare the results of the proposed model with the standard model of cosmology and the Einstein–de Sitter model. We show that the formation of the large-scale structures within the framework of a Chaplygin gas model happens earlier than predicted in the standard model

Optimization of the operating conditions of a lab scale Aljet mill using lactose and sucrose: A technical note

The results of the experiments have revealed that the optimal operating conditions for a lab scale Aljet mill are at the high level (110 psi) of the pushing nozzle and the low level (65 psi) of both grinding nozzles, or vice versa. Operating the Aljet mill at high pushing and grinding pressures also produces small particle size; however, the high pressures require more gaseous fluid making the process less efficient. At a very low pushing nozzle pressure as compared with the grinding nozzle pressure, the material kicks back from the mill, reducing the yield. Optimization of the lab scale Aljet mill operating conditions will be very useful in particle size reduction of poorly water-soluble compounds and is particularly beneficial at early stages of drug development when the drug quantity is very limited