The trend of development in pulp and paper industry is to have higher filler content in writing and printing papers. However, the strength of paper will be reduced by increasing filler content, despite of maintaining many benefits such as improving the optical properties. In this study, the effect of different consumption levels of GCC and clay fillers on the strength and optical properties of a furnish containing 70% hardwood CMP and 30% bleached Softwood kraft pulps, was investigated. The results indicated that, by using GCC filler, in comparison with clay, it is possible to produce writing and printing paper at higher brightness and strength properties.

Calcium carbonate is one of the most essential minerals with multiple applications in diverse food, pharmaceutical, chemical, plastic, and paper industries that is generated by the press, mangle, deposition, and classification. In the simulation process mentioned in this research study, a mathematical model was provided to obtain dryer yield information. According to different methods of preparation and purification of this material, spray dryers are at the end of the process as dry goods market or required properties. For this reason, the first Kinetic of the material drying obtained through the experiment and the momentum equations of suspended particles in the air, particle path differential equations in three dimensions, Reynolds number, heat, and mass transfer coefficients and then calculate the mass and energy balance for presenting a mathematical model has combined, for discover the accuracy of the model, the results compared with practical experiments. A concurrent spray dryer used in the laboratory and a computer programming language (MATLAB) were presented to compare the results of its execution with the experimental results to assess the software’s accuracy.

Introduction: Osteoporosis is a life threatening disease. One of the important etiologies of osteoporosis is low calcium intake from daily dietary intakes, making calcium salt administration in pharmacological form or as a food additive highly recommendable as a protective mechanism againt this disease, especially in women. Calcium acetate is a water soluble agent whereas calcium carbonate (which is routinely used in pharmacological forms of calcium salts) is not easily dissolved in water; hence we decided to compare the bioavailability of calcium carbonate to that of calcium acetate.Material and methods: During a clinical trial study, 20 normal female volunteers with the appropriate inclusion criteria were enrolled. On the day of study, fasting urine specimens were collected from all subjects, and 2 hours after a meal, a solution of calcium carbonate was administered to all participants and then, again, urine specimens were collected after 4 hours. After a 10 day washout period, this test was repeated with calcium acetate. The results were analyzed with paired t test.Results: The mean increase in urine calcium was 38.55 ± 6.1 mg and 36.33 ± 6.14 mg after administration of calcium carbonate or calcium acetate respectively. There was no statistically significant difference between calcium absorption from calcium carbonate and calcium acetate.Conclusion: Regarding the beneficial effects of calcium acetate as a soluble salt, in comparison with calcium carbonate and based on the results of this study indicating the similarity in calcium absorption from these two salts, calcium acetate can be administered as an appropriate substance for prevention and treatment of osteoporosis. Indeed it can be used in enriching the liquid comestibles.

Hyperphosphatemia has an important role in the development of secondary hyperparathyroidism and bone disease in patients with end-stage renal disease (ESRD). The most effective method of phosphate elimination lies with phosphate binders, the agent that more commonly used, calcium carbonate, is not an idial binding agent. In this regard, calcium acetate has been reported to have more or at least a similar phosphate binding efficacy and less pronounced hypercalcemic effect. However, this subject is still a matter of controversy. This study was designed to compare the efficiency of these salts. Preparation of calcium acetate and comparison of the phosphate binding power and hypercalcemic effect of calcium acetate with that of calcium carbonate in hemodialysis patients. Thirty stable ESRD patients undergoing regular hemodialysis for mean 4.23 years (SD 3.63) were studied. Half of the patients were started on calcium acetate for a month. Then, after two weeks wash out period, they received calcium carbonate for a month. The others followed an inverse protocol. 24 patients completed the study. A significant decrease in plasma phosphate levels was only observed after treatment with calcium acetate [6.65 mg/dL (SD 1.38 vs. 5.83 mg/dL (SD 1.55) p < 0.05]. Calcium acetate may be a better choice in handling of hyperphophatemia in ESRD patients and when calcium acetate is used, control of hyperphophatemia can be better achieved with a lower risk of hypercalcemia.

Calcium phosphate cements (CPCs), using B-tricalcium phosphate (ß-TCP, Ca3 (P04)2), dicalcium phosphate (DCP, CaHP04), calcium carbonate (Ca CO3), and hydroxylapatite (HAp, Ca10(P04)6(OH)2) as powder cement and disodium hydrogen phosphate (Na2HP04) solution as liquid component were prepared. After mixing the powder and liquid constituents, injectable and self-setting calcium phosphate cements (CPCs) were prepared with different liquid to powder ratios (UP) that formed hydroxylapatite and ß-tricalcium phosphate as the only end products, which were characterized by FTIR, XRD and SEM techniques. The results showed that, at certain concentration of Na2HP04 (6 wt%), the initial and final setting times decreased by decreasing the UP ratio.

Calcium acetate is used as an oral phosphate binder to control hyperphosphatemia in patients with chronic renal failure. Compared to calcium carbonate, control of hyperphosphatemia can be achieved at lower calcium administration with calcium acetate which likely reduces the risk of hypercalcemia. In this study, various formulations of calcium acetate tablets were prepared and their disintegration times, dissolution rates and phosphate binding capacities were determined. Dissolution test was carried out using the paddle method according to the United States Pharmacopoeia (USP XXIII). The binding efficiency of the tablets was compared by measuring the amount of insoluble phosphate after mixing with a sodium phosphate solution at pH 6. Calcium acetate tablets had a mean content of 809.6 mg of calcium acetate and a mean weight of 1087 mg. The average breaking load and disintegration times were 66.4±5.5 N and 24.5±2.1 min, respectively. Drug release after 30 and 60 min were 80.45% and 101.42%, respectively. The amount of nondissolved phosphorus following 60 min incubation of calcium acetate and/or calcium carbonate tablets were 372.8 mg (61.2%) and 463.2 mg (76.0%), respectively. Weight variation, friability, disintegration time, and dissolution rate of calcium acetate tablets were in the acceptable pharmacopoeial limits. A high phosphate binding capacity of calcium acetate tablets indicated that it can be a suitable alternative to calcium carbonate in the management of hyperphosphatemia in patients with chronic renal failure.