• Journal of dental hygiene science
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• v.23 no.1
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• pp.60-67
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• 2023

Background: In our study, a silver diamine fluoride (SDF) compound for the treatment of dental caries was synthesized to characterize its remineralization activity upon direct application to deciduous teeth. This study aimed to use microscopic computed tomography (microCT) and nanoindentation to evaluate whether SDF composite application could effectively arrest dental caries in five exfoliated primary molars. Methods: Carious teeth were extracted and visually examined using quantitative photofluorescence devices (Qraycam and QraypenTM). After performing microCT, the SDF composite was applied to the teeth according to the manufacturer's instructions. The researchers exchanged and precipitated the irritant saliva once daily for 1 week. The teeth were sectioned longitudinally through the centers of the mesial and distal surfaces, embedded, polished, and measured using nanoindentation. Thereafter, microCT was repeated. Statistical analyses were performed using GraphPad Prism software. Results: Following SDF composite application, a remineralized layer was observed on microCT images, and the hardness increased when measured using nanoindentation. We found that demineralized enamel presented with an increased number of irregular crystals in the deep carious lesion group compared with those in the shallow carious lesion group, resulting in a rougher surface. Conclusion: The SDF composite may be used for remineralization of early caries and cessation of advanced caries in primary molars.

• BMB Reports
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• v.40 no.3
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• pp.382-395
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• 2007

The herb, Cajanus indicus L, is well known for its hepatoprotective action. A 43 kD protein has been isolated, purified and partially sequenced from the leaves of this herb. A number of in vivo and in vitro studies carried out in our laboratory suggest that this protein might be a major component responsible for the hepatoprotective action of the herb. Our successive studies have been designed to evaluate the potential efficacy of this protein in protecting the hepatic as well as renal tissues from the sodium fluoride (NaF) induced oxidative stress. The experimental groups of mice were exposed to NaF at a dose of 600 ppm through drinking water for one week. This exposure significantly altered the activities of the antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione reductase (GR) and the cellular metabolites such as reduced glutathione (GSH), oxidized glutathione (GSSG), total thiols, lipid peroxidation end products in liver and kidney compared to the normal mice. Intraperitoneal administration of the protein at a dose of 2 mg/kg body weight for seven days followed by NaF treatment (600 ppm for next seven days) normalized the activities of the hepato-renal antioxidant enzymes, the level of cellular metabolites and lipid peroxidation end products. Post treatment with the protein for four days showed that it could help recovering the damages after NaF administration. Time-course study suggests that the protein could stimulate the recovery of both the organs faster than natural process. Effects of a known antioxidant, vitamin E, and a non-relevant protein, bovine serum albumin (BSA) have been included in the study to validate the experimental data. Combining all, result suggests that NaF could induce severe oxidative stress both in the liver and kidney tissues in mice and the protein possessed the ability to attenuate that hepato-renal toxic effect of NaF probably via its antioxidant activity.

• Journal of Periodontal and Implant Science
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• v.9 no.1
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• pp.33.1-33.1
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• 1979

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.3
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• pp.157-162
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• 1981

The studies we re carried out to examine the effect of soil improvement agents, such as lime, wollastonite and phosphate, in reducing the damage caused by hydrogen fluoride gas to the vegetative growth of rice. The yield loss, damage rate of the plant leaves, the fluoride of the plants were measured. The results obtained are summarized as follows : 1. The best results were obtained a treatment of lime and wollastonite. 2. The rice yield was not significantly increased by the soil improvement agents. 3. The fluoride content of the plants was positively correlated with yield loss and damage rate during vegetative growth.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.2
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• pp.141-148
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• 2001

Insecticidal effect or sulfuryl fluoride ($SO_2F_2$) to cigarette beetle, Lasiodema serricorne (F.), was studied in two different containers, one was 1m$^3$(without cardboard block) and the other was 0.5m$^3$(with cardboard block). Adults and larvae were transferred into a small metal can before placed in the containers. Each can was held for 8, 24, 48, 72, and 96 hours after $SO_2F_2$(10, 20, 30, and 40 g/$\ell$) treatment. All adults were killed in an 1m$^3$container. Larval mortality was 99 to 100% when the dosage of SO$_2$F$_2$was 10 and 20 g/$\ell$. Cardboard was attached between two 0.5m$^3$ containers ; one was fumigation area and the other was insect area. SO$_2$F$_2$ penetrated cardboard within 24 hours in most trials. $SO_2F_2$could affect all adults and larvae regardless of their susceptibility. All adults were killed at 8 hours in a 0.5m$^3$ container. But low mortality of larvae was recorded at 8 hours when small dosage was treated (30% in 10 g/$\ell$, 87.2% in 20 g/$\ell$). The mortality was increased as SO$_2$F$_2$ dosage increased. Six different metals (stainless, copper, brass, aluminum, iron, and zinc) were also tested to study metal corrosion and discoloration. No corrosion and discoloration was observed in most metals treated with $SO_2F_2$.

• Journal of the Korean Applied Science and Technology
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• v.38 no.5
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• pp.1282-1291
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• 2021

The aim of this study was to investigate the hematology and serum chemistry values on Sprague-Dawley rats, used sodium fluoride (NaF) for 5 weeks. Seven-week-old male rats were divided into nine groups and fed experimental diets with oral NaF treatment, basal diet group (BG), basal diet plus oral NaF groups (NF3~NF50). Concentrations of non-esterified fatty acid (NEFA), blood urea nitrogen (BUN), creatinine, uric acid in serum were significantly higher in the oral NaF groups than BG (𝛼=0.05). Total calcium (T-Ca) and phosphorus (Pi) concentrations was observed to be significant difference, it was decreased with an increase in the NaF levels (𝛼=0.05). Accordingly, sodium fluoride exposures and dose-response relationship, which was found on the bad influences in hematology. Such association is considered that the long-term fluoride exposure caused nephrotoxicity.

• Korean Journal of Materials Research
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• v.33 no.12
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• pp.517-524
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• 2023

BaTiO₃-Poly vinylidene fluoride (PVDF) solution was prepared by adding 0~25 wt% BaTiO₃ nanopowder and 10 wt% PVDF powder in solvent. BaTiO₃-PVDF film was fabricated by spreading the solution on a glass with a doctor blade. The output performance increased with increasing BaTiO₃ concentration. When the BaTiO₃ concentration was 20 wt%, the output voltage and current were 4.98 V and 1.03 ㎂ at an applied force of 100 N. However, they decreased when the over 20 wt% BaTiO₃ powder was added, due to the aggregation of particles. To enhance the output performance, the generator was poled with an electric field of 150~250 kV/cm at 100 ℃ for 12 h. The output performance increased with increasing electric field. The output voltage and current were 7.87 V and 2.5 ㎂ when poled with a 200 kV/cm electric field. This result seems likely to be caused by the c-axis alignment of the BaTiO₃ after poling treatment. XRD patterns of the poled BaTiO₃-PVDF films showed that the intensity of the (002) peak increased under high electric field. However, when the generator was poled with 250 kV/cm, the output performance of the generator degraded due to breakdown of the BaTiO₃-PVDF film. When the generator was matched with 800 Ω resistance, the power density of the generator reached 1.74 mW/m². The generator was able to charge a 10 ㎌ capacitor up to 1.11 V and turn on 10 red LEDs.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.389-399
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• 1996

Remineralization of acid-etched enamel across the time has been one of the curiosities in the context of the orthodontic biomechanics(Arends J. et al., IRL Press, 1, 1985), nevertheless, is so far controversial. It was the aim of this study to observe the remineralization patterns of acid-etched enamel across the time and whether the existence of fluoride might carry out any modifications. The intact buccal surfaces of the first bicuspids which was extracted for orthodontic treatment were ground smooth, and etched with a 38w/w% phosphoric acid for 60 seconds, The surface was observed by the scanning electron microscope and surface microhardness was measured after immersion in the fluoride or non-fluoride containing remineralizing solution for 0 hour, 12 hours, 1 day, 3 days, 7 days, 14 days, 28 days, and 42 days. The following results and conclusions were drawn; 1. Surface microhardness increased in both fluoride containing and non-fluoride containing solution group with time lapse. 2. In fluoride containing solution group, the surface microhardness sharply increased at the 12 hours group, on the other hand, surface microhardness increased at 3 days in non-fluoride containing solution group. 3. The difference in microhardness value between two groups manifested gradual decrease. 4. Scanning electron microphotographs disclosed that the fluoride containing solution group generated spiculate sub-stances in the 12 hours group, which was increased in number and size with time lapse. 7 days later, spherical composure was began to be produced, The spiculate substances so much increased in number that the etched enamel surface looked like flat in 42 days. 5. In non fluoride-containing solution group, there was no surface change at 42 days, perceivable in scanning electron microphotographs which could be defined as remineralization though the surface was a little rougher than the incipient etched surface. These results demonstrate that the action of the fluoride is exceedingly pertinent in the remineralization of acid-etched enamel and the remineralization process goes uninterruptedly with time lapse.

• Journal of Photoscience
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• v.11 no.1
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• pp.25-28
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• 2004

The kinetics of the loss of leaf fresh weight during incubation of barley and rice leaves in 9% or 15% NaCl solutions were biphasic, indicating the existence of a controlling mechanism for water transport. The first rapid phases reached their plateaus within 1 and 2 h in the case of rice and barley leaves, respectively. When barley leaves were fed with sodium fluoride, an inhibitor of phosphatase inhibitor, through their epicotyls for 3 h in darkness, prior to the treatment of NaCl, the biphasic pattern shown during NaCl treatment was disappeared resulting in linear decreases in the relative fresh weights. The results suggest that NaF accelerates salt-induced water efflux from plant cells, possibly by inhibiting the protection mechanism that may act in NaF-untreated leaves. The linear water loss can be explained in terms of phosphorylation of aquaporin by blocking its dephosphorylation in the presence of the phosphatase inhibitor to keep aquaporin in a phosphorylated form. However, the effect of NaF shown in barley leaves were not observed in rice. These results suggest that the regulation of water transport depends on plant species, and the mechanism for the controlling water transport in rice is different from that of barley.

• Journal of Korean society of Dental Hygiene
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• v.16 no.3
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• pp.471-477
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• 2016

Objectives: Fluoride is widely used in the prevention and control of dental caries. The purpose of this study is to examine the biological effects of Sodium fluoride on the proliferation of oral normal cell in vitro(MDPC-23, HaCaT, HGF-1 cells). Methods: The proliferation of normal cells and the cyto-skeletal change of normal cells were assessed by WST-1 assay and F-actin stain assay. The statistical significances of the resulting data were analyzed using SPSS(Window 12.0). Results: The sodium fluoride(0-12 mM) treatment decreased the cell viability in a dose and time dependent manner: HaCaT(6 h): $100{\pm}0$, $98{\pm}0.39$, $82{\pm}2.68$, $75{\pm}0.83$, $69{\pm}1$, $67{\pm}1.42%$(p<0.005); HaCaT(24 h): $100{\pm}0$, $98{\pm}1.85$, $54{\pm}0.64$, $43{\pm}0.4$, $38{\pm}0.32$, $36{\pm}0.13%$(p<0.006), MDPC-23(6 h): $100{\pm}0$, $93{\pm}1.48$, $85{\pm}0.28$, $82{\pm}1.58$, $79{\pm}1.48$, $76{\pm}1.93%$(p<0.009); MDPC-23(24 h): $100{\pm}0$, $91{\pm}1.26$, $58{\pm}0.65$, $49{\pm}1$, $44{\pm}0.74$, $2{\pm}0.05%$(p<0.005), HGF-1(6 h): $100{\pm}0$, $97{\pm}2.93$, $89{\pm}5$, $71{\pm}5.42$, $58{\pm}4.82$, $43{\pm}3.47%$(p<0.009); HGF-1(24 h): $100{\pm}0$, $97{\pm}2.05$, $73{\pm}1.73$, $22{\pm}1.61$, $14{\pm}1.73$, $7{\pm}0.85%$(p<0.005). Thus, changes in cell morphology and disruption of filamentous(F)-actin organization were observed in higher concentration. Conclusions: These results suggest that higher concentrations of fluoride lead to a reduce the number of cells and morphology change of normal cell.