• YAKHAK HOEJI
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• v.56 no.3
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• pp.164-172
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• 2012

This study was aimed to increase the solubility, dissolution and permeation rates of atorvastatin calcium (ATC) using bile salt and/or 2-hydroxypropyl-${\beta}$-cyclodextrin ($HP{\beta}CD$). From solubility studies, sodium deoxycholate (SDC) among bile salts studied was found to have the highest solubilizing effect on ATC ($4.4{\pm}0.4$ mg/ml), and the order of increasing solubility was SDC>sod. cholate>sod. glycocholate>sod. taurodeoxycholate>sod. taurocholate>conjugated bile acid. ATC solid dispersions were prepared at various ratios of drug to SDC and/or $HP{\beta}CD$, and evaluated by differential scanning calorimetry (DSC), dissolution studies and dissolution-permeation studies. DSC curves showed amorphous state of ATC in the physical mixture and solid dispersion. Dissolution rates of ATC-SDC solid dispersions and physical mixture were markedly increased at pH 6.8, but decreased at pH 1.2 with greater proportions of SDC due to the precipitation of SDC, compared with that of drug alone. On the other hand, dissolution rates of ATC-$HP{\beta}CD$ solid dispersion and physical mixture at pH 1.2 were varied with the ratio of drug to carriers. From duodenal permeation studies, it was found that fluxes of ATC (donor dose: 0.5 mg/3.5 ml) in the presence of 25 mM sodium glycocholate, SDC, sod. cholate and sod. taurocholate $(5.7{\pm}0.9$, $5.6{\pm}0.9$, $4.8{\pm}0.7$ and $4.6{\pm}0.9\;{\mu}g/cm^2/hr$, respectively) were enhanced, compared with drug alone ($3.4{\pm}0.9\;{\mu}g/cm^2/hr$). In the dissolution-permeation studies, 1 : 9 : 10 (w/w) ATC-SDC-$HP{\beta}CD$ solid dispersion increased the flux 2.2 times, compared with 1 : 5 : 4 (w/w) ATC-lactose-corn starch mixture as control. In conclusion, solid dispersions with bile salt and $HP{\beta}CD$ were found to be an effective means for increasing the dissolution and permeation rates of ATC.

• Analytical Science and Technology
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• v.13 no.2
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• pp.208-214
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• 2000

The formation and dissolution of hydroxides, carbonates and hydroxyapatite (HAp), which depend on the pH of solution, are important factor for the preparation of homogeneous and fine HAp, $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$, ceramic powder from the $Ca-PO_4-H_2O$ system. Since the solubility of each complex ion is a linear function of pH, the solubility diagram can be obtained by plotting the logarithmic molar concentrations calculated from the values of the equilibrium constants and solubility products for hydroxides, carbonates, and hydroxyapatite. The optimum pH condition for the formation of single phase $Ca_{10-x}(HPO_4)_x(PO_4)_{6-x}(OH)_{2-x}(x=0)$ powder in $Ca-PO_4-H_2O$ system at $25^{\circ}C$ was estimated as $10.5{\pm}0.5$ through the theoretical consideration. The HAp powder dried at $80^{\circ}C$ showed a fine agglomerated particles with a size of 75 nm. The HAp powder calcined at $1,000^{\circ}C$ consisted of nearly homogeneous particles with a size of 450 nm. Even though the dried HAp particles consisted of agglomeration, mechanical properties were superior due to fine microstructure after sintering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3260-3268
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• 2009

A test apparatus has been fabricated to simulate chemical effect on head loss through a strainer in a pressurized water reactor (PWR) containment water pool after a loss of coolant accident (LOCA). Tests were conducted under condition of same ratio of strainer surface area to water volume between the test appratus and the containment sump. A series of tests have been performed to investigate the effects of spray, existence of calcium-silicate with tri-sodium phosphate (TSP), and composition of materials. The results showed that head loss across the chemical bed with even a small amount of calcium-silicate insulation instantaneously increased as soon as TSP was added to the test solution. Also, the head loss across the test screen is strongly affected by spray duration and is increased rapidly at the early stage, because of high dissolution and precipitation of aluminum and zinc. After passivation of aluminum and zinc by corrosion, the head loss increase is much slowed down and is mainly induced by materials such as calcium, silicon, and magnesium leached from NUKONTM and concrete. Furthermore, it is newly found that the spay buffer agent, tri-sodium phosphate, to form protective coating on the aluminum surface and reduce aluminum leaching is not effective for a large amount of aluminum and a long spray.

• Journal of Soil and Groundwater Environment
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• v.29 no.5
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• pp.14-26
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• 2024

This study investigated the effectiveness of calcium polysulfide (CPS; CaS_x) injection for the in-situ immobilization of cadmium and zinc-contaminated groundwater. The research focused on the impact of CPS injection on groundwater quality parameters, such as dissolved oxygen (DO), oxidation-reduction potential (ORP), and pH, as well as heavy metal precipitate formation and aquifer's microbial community dynamics on a field scale. The results demonstrated that the injected CPS formed a reactive zone, effectively reducing cadmium and zinc concentrations for a limited period. However, contaminant rebound occurred over time, necessitating repeated CPS injections. A single injection of CPS achieved a removal efficiency of 70~99%, lasting approximately 20 days. In contrast, repeated injections sustained the removal effects up to 37 days. Chemical analyses confirmed the precipitation of cadmium and zinc sulfide (CdS and ZnS), which remained stable in the aquifer even 86 days post-injection. Elemental sulfur (S) was detected in a significant quantity, contributing to the observed low DO levels. Microbial community exhibited a shift from an initial prevalence of sulfur-oxidizing and iron-oxidizing bacteria to a later dominance of sulfate-reducing bacteria following the cessation of high DO recycled water inflow, potentially enhancing the formation of CdS and ZnS.

• Journal of the Korean Society of Tobacco Science
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• v.9 no.1
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• pp.11-17
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• 1987

KA 101 and Xanthi-Basma were cultivated in Korea and Greece to compare the respective responses to environment and cultivation method on their growth characteristics and some properties of harvested leaves during 1984 and 1985. The contents of clay, calcium, organic matter and pH were higher in the soil of greece than that of Korea. Sunshine hours and precipitation in Greece during harvest and curing season were 8.6 hours per day and 53.3mm compared to that of 3.8 hours per day and 320mm in Korea, respectively. The plant height, leaf size and yield decreased, and days to flower was shorter 8-11 days in greek grown plants. The dehydration and curing process in Greece was linear and rapid due to the constant daily change of temperature and relative humidity with dry weather during curing season during curing season. But those process in Korea was variable and tardy due to rainy weather. Cured leaf ratio increased with upper stalk leaves in Greece but it was rather lower at top stalk position in Korea. The harvested green leaf cultivated in Greece showed higher contents of petroleum ether extract, total nitrogen and nicotine, but lower contents of reducing sugar and lower ratio of protein nitrogen to total nitrogen than in Korea.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1253-1264
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• 2015

This study assessed the fertilizing value of struvite deposit recovered from swine wastewater in cultivating Chinese cabbage. Struvite deposit was compared with commercial fertilizers: complex, organic and compost to evaluate the fertilizing effect of struvite deposit. Laboratory pot test obviously presented that the struvite deposit more facilitated the growth of Chinese cabbage than organic and compost fertilizers even though complex fertilizer was the most effective in growing Chinese cabbage. It was revealed that the growth rate of Chinese cabbage was simultaneously controlled by phosphorus (P) and potassium (K). Also, the nutrients such as nitrogen (N), P, K, calcium (Ca) and magnesium (Mg) were abundantly observed in the vegetable tissue of struvite pot. Specifically, P was the most abundant component in the vegetable tissue of struvite pot. Meanwhile, the utilization of struvite as a fertilizer led to the lower accumulation of chromium ($Cr^{6+}$) than other pots, except for compost fertilizer pots, and no detection of cadmium (Cd), arsenic (As) and nickel (Ni) in the Chinese cabbage. The experimental results proved that the optimum struvite dosage for the cultivation of Chinese cabbage was 2.0 g struvite/kg soil. On the basis of these findings, it was concluded that the struvite deposits recovered from swine wastewater were effective as a multi-nutrient fertilizer for Chinese cabbage cultivation.

• Journal of Yeungnam Medical Science
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• v.33 no.1
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• pp.68-71
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• 2016

Tumoral calcinosis (TC) is a condition resulting from extensive calcium phosphate precipitation, primarily in the periarticular tissues around major joints. Calciphylaxis is a fatal ischemic vasculopathy mainly affecting dermal blood vessels and subcutaneous fat. This syndrome is rare and predominantly occurs in patients with end-stage renal disease. Here, we report on a rare case involving a patient with TC complicated with calciphylaxis. Our patient was a 31-year-old man undergoing hemodialysis who presented with masses on both shoulders and necrotic cutaneous ulcers, which were associated with secondary hyperparathyroidism, on his lower legs. He underwent subtotal parathyroidectomy, and sodium thiosulfate (STS) was administered for 27 weeks. Twenty months after beginning the STS treatment course, he experienced dramatic relief of his TC and calciphylaxis.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.11-18
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• 1994

We have studied the iron uptake by the purified brush-border membrane vesicles (BBMVs) to determine the effect of fructose on the absorption of iron. BBMVs were prepared by the modified calcium precipitation method, The degree of purification was routinely assessed by the marker enzyme, alkaline phosphatase, and the functional integrity was tested by $D-[1-^3H]glucose$ uptake. The appearance of membrane vesicles was shown by transmission electron microscopy (TEM). The uptakes of complexes of labeled iron $[^{59}Fe]$ with fructose and ascorbate were measured with a rapid filtration technique, The uptake rate and pattern of the two iron-complexes, Fe(III)-fructose and Fe(III)-ascorbate, were also observed. A typical overshooting uptake of D-glucose was observed with peak value of $2{\sim}3$ times higher concentration than that at equilibrium. This result was similar to other studies with BBMVs. TEM showed that the size of BBMVs was uniform and we can hardly find any contaminants, Fe(III)-fructose has the higher value of $V_{max}$ and the lower value of Km than those of Fe(III)-ascorbate, respectively. It may be concluded that D-fructose is more effective in promoting the iron absorption than ascorbate.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.521-527
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• 2017

Phosphorus is one of the limiting nutrients for the growth of phytoplankton and algae and is therefore one of leading causes of eutrophication. Most phosphorous in water is present in the form of phosphates. Different technologies have been applied for phosphate removal from wastewater, such as physical, chemical precipitation by using ferric, calcium or aluminum salts, biological, and adsorption. Adsorption is one of efficient method to remove phosphates in wastewater. To find the optimal media for phosphate removal, physical characteristics of media was analysed, and the phosphate removal efficiency of media (silica sand, slag, zeolite, activated carbon) was also investigated in this study. Silica sand showed highest relative density and wear rate, and phosphate removal efficiency. Silica sand removed about 36% of phosphate. To improve the phosphate removal efficiency of silica sand, Fe coating was conducted. Fe coated silica sand showed 3 times higher removal efficiency than non-coated one.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.907-915
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• 2015

The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.