• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.93-107
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• 2005

The estuary of Nakdong River area including Noksan industrial complex and Busan New Port is composed of thick unconsolidified sediments containing abundant clay, and thus is a potential hazardous area of ground subsidence. We analyzed mineral compositions and geotechnical properties of the clay sediments that sampled from 4 boreholes of the area, and examined vertical variations and their correlations. The results showed correlations between some mineral constituents and geotechnical properties of clay sediments. A positive correlation showed between quartz content and wet unit weight, whereas a negative correlation showed between quartz content and liquid limit. Feldspar content and water content showed a negative correlation, whereas content of clay minerals and liquid limit showed a positive correlation. And also, there is a negative correlation between content of clay minerals and wet unit weight. Correlation equations are obtained from the multiple regression analyses among plastic index, content of clay mineral, smectite and clay fraction.

• Resources Recycling
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• v.32 no.6
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• pp.18-24
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• 2023

This study undertook initial investigations into the carbonation of chlorine bypass dust, aiming to apply it as a raw material for cement and as an admixture for concrete. Various experimental methods, including XRD(X-ray diffraction), XRF(X-ray fluorescence), and particle size distribution analyses, were employed to verify the physical and chemical properties of chlorine bypass dust, with and without water washing. The mineral carbonation extent of chlorine bypass dust was examined by considering the dust type, stirring temperature, and experiment duration. Notably, a higher degree of mineral carbonation was observed in water-washed bypass dust than its non-water-washed counterpart, indicating an elevated calcium content in the former. Furthermore, an augmented stirring temperature positively impacted the initial stages of mineral carbonation. However, divergent outcomes were observed over time, contingent upon the specific characteristics of dust types under consideration.

• Journal of the Korean Electrochemical Society
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• v.17 no.1
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• pp.26-29
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• 2014

The corrosion behavior of stainless steel 304 (SS 304), titanium, nickel and aluminium is studied by immersion and anodic polarization tests in non-aqueous electrolytes. Tetraethyl ammonium tetrafluoroborate is used as a supporting electrolyte in the three kinds of solvents. The immersion test shows that chemical corrosion rate in propylene carbonate-based electrolyte is lower than those in acetonitrile- or ${\gamma}$-butyrolactone-based electrolytes. Surface analyses do not reveal any corrosion product formed after the immersion test. In the anodic polarization tests, a higher concentration of supporting electrolyte gives a higher current density. In addition, a higher temperature increases the current density in the active region and reduces the potential range in the passive region. SS 304 shows the highest corrosion potential while Al shows the lowest corrosion potential and the highest current density in all studied conditions. Based on the conducted corrosion tests, the corrosion resistance of metal substrates in the organic solvents can be sorted in descending order as follows: SS 304 - Ti - Ni - Al.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.82-91
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• 2012

The heavy metal effects on the degradation of fluorene by Sphingobacterium sp. KM-02 was determined in liquid cultures. The results showed that 10 mg/L cadmium, copper, zinc, and lead not only affected the growth of KM-02 with fluorene but also the ability of growing or resting cells to degrade this compound. Growth and fluorene degradation were strongly inhibited by cadmium and copper at 10 mg/L, while the inhibitory effect of zinc and lead at the same concentration or at 100 mg/L were not significant. In contrast, arsenic did not affect degradation or growth, even at very high concentrations of 100 mg/L. Subsequent analyses additionally revealed that concentrations of arsenic remained unchanged following incubation, while those of cadmium and copper decreased significantly.

• Economic and Environmental Geology
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• v.19 no.2
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• pp.85-96
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• 1986

The Bupyeong Silver mine which is located approximately 35km west of Seoul is currently the leading silver producer in Korea. The deposits occur as stockwork deposits hosted in Jurassic pyroclastic rocks. Occurrences of ore deposits and mineral paragenesis suggest a division of mineralization into four stages: Stage I, deposition of iron oxide and base metal sulfides; Stage II, deposition of tin oxide and silverm inerals; stage III, deposition of native silver and other silver minerals; Stage IV, formation of pyrite bearing siderite veinlets, Silver minerals in ore are native silver, argentite, freibergite, pyrargyrite, canfieldite, polybasite, dyscrasite and Ag-Fe-S mineral. The most important silver mineral is native silver among them. Chemical composition of important silver minerals were determined by electron probe microanalyser. Assay, size and modal analyses for floatation products were carried out. In floatation products, relative proportion of native silver for total important silver minerals have following ranges: feed, 64.7 to 74.74 wt.%; A-cleaner concentrate, 80.58 to 98.79 wt.%; and final tailing, 28.12 to 72. 57 wt. %. Average degree of liberation for native silver in feed and A-cleaner concentrate are 60.49% and 77.57% respectively. Negative relationship can be recognized between native silver and argentite in their abundance and behavior in floatation precesses.

• Biomedical Science Letters
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• v.16 no.3
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• pp.169-177
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• 2010

Osteoporosis is a disease that increases the fracture rates and a major cause of increased mortality and morbidity in the elderly people. This study is to determine which components of body composition and metabolic syndrome risk factors are important to bone health, we analysed the relationship among bone mineral density (BMD), body composition and metabolic syndrome risk factors in females. Totally 630 females participated in a medical check-up program (mean age 47 years) were selected for this study. Body composition analysis was performed by segmental bioelectrical impedance method, muscle mass, and percent body fat were measured. We also measured metabolic syndrome risk factors including abdominal obesity, HDL-cholesterol, triglyceride, blood pressure and fasting glucose level. Metabolic syndrome was defined by NCEP-ATP III criteria. The lumbar spine and femoral neck BMD were measured using the dual energy X-ray absorptiometry. Osteopenia and osteoporosis were observed in 180 and 51 persons, respectively. Muscle mass and HDL-cholesterol decreased in osteopenia and osteoporosis groups compared to the control group, and the grade was shown progressively by the symptoms. Significant positive correlation between BMD and muscle mass was observed. Multi variable regression analyses showed that % body fat and muscle mass were independent predictors of BMD after adjustment of age, height and weight. In conclusion, the BMD showed negative correlation with the metabolic and body composition was associated with BMD.

• Korean Journal of Adult Nursing
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• v.17 no.1
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• pp.23-33
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• 2005

Purpose: To evaluate physical characteristics, lifestyle related to bone-health, and bone mineral density (BMD) in mothers and their daughters and to determine the predictors of BMD. Method: BMDs at the forearm, lumbar spine, and femur were measured in 101 healthy, mother-daughter pairs by dual energy X-ray absorptiometry. Mother-daughter differences between general characteristics, means for BMDs were assessed by ${\chi}^2$-test, t-tests. Multiple regression analyses were used to identify predictors of BMD in each group. Results: Mothers had significantly higher BMD than their daughters at forearm, lumbar spine, and femur. The predictors of mothers' BMDs were body weight, body mass index (BMI) and percentage body fat, explaining 5.1~31.6% of the variation in BMDs. BMI, percentage body fat and their mother's BMD of the corresponding site bone were predictors in daughters, explaining 17.5~31.6% of the variations in BMDs. Conclusion: These results indicate the importance of weight on bone that the BMDs seems to be related to fat free mass both in young-adult daughters and in middle aged mothers. These also suggest the importance ofintervention for the development of BMD in daughter of mother with low BMD.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.818-826
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• 1995

The present study was undertaken to investigate the crystal growth onto enamel mineral and synthetic hydroxyapatite seeds in media resembling the enamel fluid composition. Effects of fluoride at low concentrations on the precipitation were also examined in a benchtop crystal growth model adopting a miniaturized reaction column. X-ray diffraction and Fourier transform infrared spectroscopy(FTIR), as well as chemical analyses, were employed for characterization of both seed materials before and after experimentation. Remarkable findings were that (1) both biological and synthetic seeds at the same total surface areas yielded rather similar precipitation rates at all levels of fluoride concentration in solution and (2) the precipitation rate was accelerated in a manner depending on fluoride concentrations in media. FTIR differential analysis disclosed that the precipitating phase was characterized as poorly crystallized apatite, which incorporated subtle carbonate. Most of the fluoride ions in soution were readily incorporated into crystals. The overall results support the view that the seeded crystal growth model is of value to gain insight into the mechanism of enamel crystal growth under fluoride regimens.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.217-227
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• 2009

Heavy minerals in the marine sand near Haeju bay, Hwanghae-do, North Korea were separated using the gravity and the magnetic separators. And their mineralogical study was carried out. Ilmenite, magnetite, hematite, zircon and monazite were observed as the valuable minerals, and quartz, orthoclase, muscovite, hornblende and garnet existed as gangue minerals. In the result of quantitative analysis with SIROQUANT program, the contents of the valuable minerals separated with the 2nd gravity separation (the shaking table separation), the 1st magnetic separation (rare earth magnetic separation) and the 2nd magnetic separation (the Eddy current magnetic separation) were increased into 4%, 10% and 76~89% (under the condition of 7000 G and 10000 G in magnetic strength), respectively. The contents of ilmenite, monazite and zircon recalculated from the chemical composition differed from the results of the quantitative analyses by SIROQUANT program, but the entire tendency bears some analogy with it. Under the conditions of 7000 G and 10000 G in 2nd magnetic separation the contents of ilmenites were concentrated with 53% and 66%, respectively. The content of monazite was 1.2% in the magnetic fractions of the 1st magnetic separation. The content of zircon was shown 1.4% under the condition of 10000 G in the 2nd magnetic separation, and was displayed 9% in +50 mesh of non-magnetic fraction of 1st magnetic separation, especially.