Calcium oxalate monohydrate

Calcium oxalate monohydrate Calcium phosphate (dibasic) Calcium pyrophosphate Calcium sodium phosphate Calcium sulfate Calcite... 

The crystal growth rates can be directly determined from the second and third moment as described above. The calculated rates for calcium oxalate here are in the range 0.75 x 10 to 4.7 x 10 m/s. Literature values for the growth rate of calcium oxalate monohydrate vary considerably 1.08 x 10 m/s (Kavanagh, 1992), 3.4 X 10 to 5.0 x 10 m/s (Garside etal., 1982) and 2.8 x lO to 1.11 X 10 m/s (Nielsen and Toft, 1984). The values obtained from the experiments are therefore within the range of the literature data. It should be borne in... 

Bramley, A.S., Hounslow, M.J. and Ryall, R.L., 1996b. Aggregation during precipitation from solution. Kinetics for calcium oxalate monohydrate. Chemical Engineering Science, 52, lAl-lSl. 

Collier, A.P. and Hounslow, M.J., 1999. Growth and aggregation rates for calcite and calcium oxalate monohydrate. American Institute of Chemical Engineers Journal, 45, 2298-2305. 

Gardner, G.L. and Nancollas, G.H., 1975. Kinetics of dissolution of calcium oxalate monohydrate. Journal of Physical Chemistry, 79, 2597-2600. 

Mumtaz, H.S., Hounslow, M.I., Seaton, N.A. and Paterson, W.R., 1997. Orthokinetic aggregation during precipitation A computational model for calcium oxalate monohydrate. Transactions of the Institution of Chemical Engineers, 75, 152-159. 

Calcium oxalate monohydrate has a solubility of 0.0067 g and 0.0140 g L 1 at 25° and 95 °C respectively. The solubility is less in neutral solutions containing moderate concentrations of ammonium oxalate owing to the common-ion effect (Section 2.7) hence a dilute solution of ammonium oxalate is employed as the wash liquid in the gravimetric determination. 

A. The thermal decomposition of calcium oxalate monohydrate. This determination may be carried out on any standard thermobalance. In all cases the manufacturer s handbook should be consulted for full detailed instructions for operating the instrument. 

Both calcium oxalate monohydrate and dihydrate - whewellite and weddelite - contain eight-coordinated Ca2+ in distorted square-antiprismatic geometry, but there is one coordinated water in the former, two in the latter. Whewellite has a layer structure through the sharing of three edges of each coordination square-antiprism with three adjacent polyhedra weddelite has a chain structure (128). The trihydrate also contains eight-coordinated Ca2+ (129). 

Calcium oxalate monohydrate responsible for the formation of most kidney stones significantly increased mitochondrial superoxide production in renal epithelial cells [42], Recombinant human interleukin IL-(3 induced oxygen radical generation in alveolar epithelial cells, which was suppressed by mitochondrial inhibitors 4 -hydroxy-3 -methoxyacetophe-none and diphenylene iodonium [43]. Espositio et al. [44] found that mitochondrial oxygen radical formation depended on the expression of adenine nucleotide translocator Anti. Correspondingly, mitochondria from skeletal muscle, heart, and brain from the Antl-deficient mice sharply increased the production of hydrogen peroxide. 

Fig. 37. Effect of sample packing on the dehydration course of calcium oxalate monohydrate shown by mass spectrometry...

The thermogram for calcium oxalate monohydrate (CaC204.H20) is presented in Figure 11.2. The successive plateaus correspond to the anhydrous oxalate (100-250°C), calcium carbonate (400-500°C), and finally calcium oxide (700-850°C). In other words, these plateaus on the decomposition curve designate two vital aspects, namely ... 

Figure 11.2 Thermogravimetric Evaluation of Calcium Oxalate Monohydrate heated at the rate of 6°C min-1. 

Stage 1 The water of hydration (or crystallization) from calcium oxalate monohydrate is lost which corresponds to 2.46 mg (12.3%) equivalent to 1 mole of H20 in the temperature range 100-250°C. 

What are the pharmaceutical applications of TGA Explain the interpretation of thermogram obtained by TGA of calcium oxalate monohydrate being heated at the rate of 6°C per minute. 

These solid phases are connected to the components in Fig. 4, with which they are in reversible equilibrium. For example, if magnesium ion were added to a complex solution containing solid calcium oxalate monohydrate (COM), the magnesium would compete with calcium for an increased share of the oxalate this would reduce the amount of the calcium oxalate complex, and finally a small amount of calcium oxalate sohd would dissolve to restore the complex concentration to its equilibrium value. In urine, this picture must be extended to account for the molecular substances that coat crystals and reduce access of the solution to the surface coated crystals do not redissolve readily. 

Calcium oxalate monohydrate (CaC204-H20), SOLUBILITY PRODUCT... 

Calcium oxalate monohydrate (CaC204 H20) is a material widely used for the calibration of TGA equipment. It shows the following changes with increasing temperature (mass loss regions were obtained at a heating rate of 15°C/min) ... 

Carr et al., (2006) showed that down-regulation of CLCN5 in a collecting-duct model system results in mis-localisation of annexin 2 from the cell cytoplasm to the cell membrane and onto the cell surface. Annexin 2 has been identified as the receptor for calcium oxalate monohydrate crystals on the surface of MDCKI epithelial cells (dog kidney cells) (Kumar et al., 2003). The authors have shown that increased surface availability of annexin 2 results in increased binding of crystals to the cell, and that this could be inhibited by treating the cells with anti-annexin 2 antibodies. 

Kumar, V., Farell, G., Deganello, S., and J.C. Lieske, 2003, Annexin II is present on renal epithelial cells and binds calcium oxalate monohydrate crystals. J Am Soc Nephrol. 14(2) 289-97. 

Courtault [137] has critically considered calibration of TG, MS and the TG-MS coupling. The TG (-MS) apparatus is often calibrated with calcium oxalate monohydrate. Bart and co-workers [25] have discussed critically the calibration and interlaboratory reproducibility of TG-MS. 

H2) Freeman, S., and B. Carroll The application of Thermoanalytical techniques to reaction kinetics. The Thermogravimetric Evaluation of the Kinetics of the Decomposition of Calcium Oxalate Monohydrate. J. Phys. Chem. 62, 394/ 397 (1958). 

In practice AT vs furnace temperature is plotted givinga thermogram of the type illustrated in figure 11.8. Figure 11.9 shows a curve for the DTA examination of calcium oxalate monohydrate exemplifying also the effect of changing the atmosphere from nitrogen to air. 

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