Effect Of Calcium Sulfate Research Articles

Effect of calcium sulfate in fastening consolidation of distracted bone

Effect of calcium sulfate in fastening consolidation of distracted bone

Effect of calcium sulphate on the healing of periodontal intrabony defects

The purpose of this series of three studies was to evaluate the regenerative potential of calcium sulphate in the treatment of periodontal intrabony defects.

The effects of calcium sulfate on healing of 1-wall intrabony defects in dogs

The effects of calcium sulfate on healing of 1-wall intrabony defects in dogs

The effect of Calcium Sulfate on the periodontal healing of 2-wall intrabony defects in dogs

There have been numerous bone graft materials used in periodontics, in an attempt to reach the main goal of periodontal therapy, i.e. the regeneration of periodontal tissue lost due to destructive periodontal diseases. Autogenous bone grafts, with their ability to retain cell viability and a high potential of revascularization as well as low disease transmission, have been widely favored1). However, autogenous bone grafts generally require secondary surgical sites, and have limitations in the amount of grafts that can be procured. A search for the allografts and synthetic bone substitutes that can match the clinical success of autogenous bone grafts without the limitations inherent in the autogenous grafts has been going on for decades. Some of the materials studied include plaster of Paris2, 3), hydroxyapatite4, 5), calcium carbonate6), and decalcified freezedried bone7), to name a few. The hemihydrate of calcium sulfate, also known as plaster of Paris, is prepared by heating gypsum8). When the dry powder is mixed with water, calcium sulfate hardens to form a solid mass of crystals. Initially, medical use of calcium sulfate was limited to a cast which immobilize the injured limb or incorporation in bandages and splints. However, there was a report in 1892 by Dressman as described by Peltier2), where bone cavities were filled with plaster of Paris and later found to be filled with solid bone. Since then, the use of calcium sulfate in animals and in human orthopedic and dental bone defects has been reported in numerous publications. These reports generally agree that the plaster of Paris does not induce inflammatory reaction more than what is present before the grafting8), and the grafted area is histologically normal. A number of animal studies using calcium sulfate suggest that calcium sulfate does not inhibit the osteoblast activities, and may provide conducting matrix for ingrowth of blood vessels and osteogenic cells. However, Shaffer & App3) in 1971 reported that no new bone formation was found in the intrabony defects 대한치주과학회지 : Vol. 27, No. 2, 1997

Direct and indirect effects of calcium sulfate and nitrogen on growth and succession of trees on the Tanana River floodplain, interior Alaska

Seedlings of Alaskan floodplain species (Populusbalsamifera L. (balsam poplar), Alnustenuifolia Nutt. (thinleaf alder), and Piceaglauca (Moench) Voss (white spruce)) and an upland species (Populustremuloides Michx. (trembling aspen)) were grown in early-successional floodplain soils treated with a floodplain salt (calcium sulfate, CaSO4), an osmoticant (polyethylene glycol), and nitrogen. CaSO4 reduced the growth of aspen relative to controls but also reduced the growth of some typical floodplain colonizers (alder at low nitrogen and poplar at high nitrogen). Aspen and poplar were the most rapidly growing species, even when grown with salt or polyethylene glycol. Effects of CaSO4 on growth, therefore, do not explain why aspen is less abundant on the floodplain than are typical floodplain colonizers. CaSO4 reduced growth directly in salt-sensitive species, judging from the insensitivity of water potential, transpiration, and photosynthesis to CaSO4 addition. Tissue concentrations of nitrogen and phosphorus were unaffected by CaSO4, suggesting that the declines in nutrient accumulation by salt-sensitive species in response to CaSO4 addition reflected a decline in nutrient demands for growth rather than being the cause of the reduction in growth. Growth and nutrient accumulation were stimulated by nitrogen addition in all species. We suggest that floodplain salts may be important in succession by slowing the establishment and growth of alder, which is responsible for most of the nitrogen acquired by plants during succession.

The Effect of Calcium Sulfate (Gypsum) in Combination with Different Sources and Forms of Calcium Carbonate on Acid-Base Balance and Eggshell Quality

Two experiments were conducted to determine the maximum level of gypsum (calcium sulfate) that can be used safely in the laying ration. Diets containing supplemental calcium as gypsum, pulverized limestone, oyster shell, and various combinations of these were used in Experiment 1. In Experiment 2, the effect of a combination of gypsum and calcium chips (particulated form of limestone) was also studied.Egg production performance was not adversely affected when gypsum supplied up to two-thirds of the supplemental calcium regardless of the calcium sources used to provide the remaining one-third. Egg production and body weight gain were reduced when gypsum supplied all the supplemental calcium. Excreta moisture, shell quality, blood indicators of acid-base balance (pH, HCO–3 and base excess), and calcium retention were reduced with increased levels of gypsum substituted for pulverized limestone. The adverse effect on shell quality of supplying up to two-thirds of the calcium as gypsum was alleviated when the remaining part was provided by oyster shell but not when it was provided by calcium chips. The data suggest that the beneficial effect of oyster shell as compared with calcium chips in alleviating the adverse effect of gypsum on shell quality was due to its higher solubility and larger proportion of larger particles. The results indicate that gypsum can be used safely in laying hen rations to supply up to two-thirds of the supplemental calcium provided that the remaining part is supplied by oyster shell.

Termination Criteria for Clay Permeability Testing

Linear regression and related statistical techniques are used to analyze hydraulic conductivity, (k) data, and test termination criteria are suggested. These criteria include that the slope of k versus pore volumes does not differ significantly from zero and that a minimum number of permeant pore volumes pass through the clay to provide saturation. To simplify the presentation, specific characteristics of the clay/chemical combination, such as cation exchange capacity, are not a focus of this presentation. The use of clay liners at hazardous waste disposal sites has prompted an interest in the k of clays exposed to chemicals, k is commonly determined in the laboratory using fixed or flexible wall permeameters and consolidometers, but past and current procedures reflect a lack of consistency in termination criteria for such tests. Fixed wall permeameters are used to study the effects of calcium sulfate and two simulated waste chemicals on three field clays. Results indicate the usefulness of the analysis i...

Effect of Calcium Sulfate on Iron and Zinc Uptake in Sorghum1

AbstractIn a recent report, Olsen and Watanabe found significant increases in uptake of Fe and Zn in sorghum (Sorghum bicolor L. Moench. var. RS‐610) due to calcium sulfate treatments in four of six soils. Our research extended this sulfate × micronutrient interaction study to evaluate the possible ameliorative effect of sulfate on Fe and Zn as influenced by P and CaCO3 levels. A greenhouse factorial experiment was designed using two levels of P, sulfate, and CaCO3 in a Nunn loam soil (fine, montmorillonitic mesic Aridic Argiustoll) with sorghum as the test plant. Plants were grown for 60 days, and then sectioned into top leaves, bottom leaves, and stems. Data collected included dry matter, and P, Fe, and Zn concentrations in the various parts.Dry matter yields and P concentrations were increased with added P treatments. Phosphorus with added CaCO3 resulted in the lowest Fe and Zn concentrations in the top leaves while P with added sulfate resulted in the highest. These treatment effects were generally reversed in the bottom leaves. Phosphorus, and Fe and Zn, showed different mobility relationships. Total Fe uptake was increased 20% and Zn uptake also tended to increase with added sulfate. Apparently, the top leaves were supplied with Fe through internal transfer of Fe from bottom to top leaves, and external transfer (soil), while the Zn transfer was largely through internal transfer processes.

Effect of Clays, Limestone, and Gypsum on Soluble Oil Flooding

Introduction In our investigation of the soluble oil flooding process we observed that the process is less efficient in some porous rocks than in others. There are two basic porous rocks than in others. There are two basic factors that affect the oil displacing action of the soluble oil process:composition of interstitial fluids, andcomposition of reservoir rock. The literature has much data showing that composition of interstitial water, particularly the presence of divalent ions, greatly affects the efficiency of a soluble oil flood. This study is not concerned with that aspect of the problem. problem. This study is concerned with the effect of rock minerals on soluble oil flooding. We evaluated the possibility that certain rock minerals can drastically possibility that certain rock minerals can drastically affect the efficiency of the soluble oil flood. One previous study has shown some of the possibilities in previous study has shown some of the possibilities in this regard. Experimental Procedure The flooding experiments were conducted in unconsolidated sandpacks (No. 16 sand) containing from 0 to 2 percent of either gypsum, montmorillonite clay, or calcium carbonate. The sand was packed in 3-ft long, 2-in. diameter plastic tubes to a porosity of about 40 percent and a permeability of about 4 darcies. In preparation for the flooding experiments, the systems were first saturated with brine or fresh water, permeability was determined, and then crude oil was permeability was determined, and then crude oil was injected to irreducible water. Next, the system was waterflooded to residual oil saturation, and, finally, a soluble oil flood was made. Oil saturations after waterflooding ranged from 28 to 32 percent PV. In each soluble oil flood, 0.03 PV of soluble oil was injected and followed by 1 PV of polyacrylamide solution that had a viscosity of about 32 cp. Effect of Calcium Sulfate On the Soluble Oil Process Gypsum (CASO4 2H2O) is a slightly water-soluble mineral present in some oil reservoirs. Its maximum solubility is about 2,000 ppm in fresh water, and about 7,000 ppm in NaCl brine. We ran several flood tests to determine whether this slightly soluble mineral would affect the soluble oil flooding process. The data in Fig. 1 show that 0.5 percent or more gypsum in the sand reduces oil recovery by the soluble oil-polymer flood. With no CASO4 present, oil recovery was 96 percent, while with 2 percent CASO4 in the sand, oil recovery was 55 percent. The most probable mechanism by which gypsum reduces the oil-displacing effectiveness of the soluble oil-polymer process is related to the dissolution of solid gypsum by flooding solutions and the consequent reaction of dissolved Ca++ with flooding chemicals. Dissolved Ca++ can affect the soluble oil flooding process in two ways:it can precipitate some process in two ways:it can precipitate some of the petroleum sulfonates, andit can reduce the viscosity of polyacrylamide solution. JPT P. 179

The effect of calcium sulfate as the binder in deae-cellulose thin-layer chromatography for separating nucleic acid degradation products

Thin-layer techniques involving layers of diethylaminoethyl-cellulose, with and without CaSO4, are presented for the complete separation and quantitative elution of the major degradation products of ribonucleic acid and deoxyribonucleic acid. Emphasis is given to the effects of the pH of the material to be separated and to the percent CaSO4 present in the cellulose as “binder”.

Soil salinity studies. I—effect of calcium sulphate on the correlation between plant growth and electrical conductivity of soil extracts

AbstractThe relation between the growth of lettuce and soil salinity (estimated by seven methods) was studied in the presence of varying levels of calcium sulphate. Lettuce were grown in pots receiving five levels of a mixture of potassium nitrate and diammonium hydrogen phosphate and four levels of calcium sulphate in factorial combination.Soil salinity was measured by the electrical conductivity of displaced soil solutions, saturation extracts, and soil suspensions prepared at water/soil (air‐dry) ratios of I: I, 2.5: I and 5: I. Direct measurements of electrical conductivity were also made in the saturation pastes, and a tentative procedure involving saturation of all 2.5: I soil suspensions with calcium sulphate was examined.Correlation between fresh weights of lettuce and conductivity measurements at water/ soil ratios of 5: I and 2.5: I was unsatisfactory, but was better at a ratio of I: I. Highly significant correlations of plant weight with measurements in saturation extracts and displaced soil solutions were obtained. Direct measurements in the saturation pastes gave correlations almost identical with those for filtrates from the pastes, but the effect of differences in soil texture on this relationship remains to be examined. The highest correlations of all were obtained in soil suspensions saturated with calcium sulphate.