• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.683-693
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• 2001

The purpose of this study was to evaluate the effects of Er:YAG laser on cutting efficacy and its histologic findings. Dentin specimens of human premolars and molars were used and irradiated by Er:YAG laser with noncontact handpiece type delivery system under different treatment condition of irradiation time. Cavity pattern and volume were evaluated to determine the cutting efficacy and following results were obtained. 1. Cutting volume of sound dentin was getting larger with time immersed in water increase 2. With the condition of irradiation (150mJ, 10Hz, 30sec), surface irregularity was more increased in sound dentin comparing to carious dentin. For the light microscopic examination, dentinal tubules were opened and ash flecks and cracks were noted with inconsistence of dentinal tubules. 3. In case of 30 sec. irradiation in carious dentin, dark zone was limited to small focus whereas 1 min. irradiation, more wider, and cracks were noted in the perpendicular to direction of dentinal tubules. For the 2 min. irradiation, cavity was the widest and more cracks were found.

• English Language & Literature Teaching
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• v.18 no.1
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• pp.69-89
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• 2012

This paper explored the effects of extensive reading (ER) on Korean university students' L2 reading proficiency and reading rates. This study also illustrated how ER can be integrated into a university English reading class. Seventeen students who took a summer reading course participated in this study. Data were gathered through pre- and post- tests in terms of participants' reading comprehension proficiency and reading rates and post- questionnaire with regard to their attitudes toward L2 storybook reading after they have experienced it. The analysis was carried out using the Paired Samples t-test. It was revealed that ER has a positive effect on the enhancement of the participants' reading comprehension and reading rates. The participants showed their continued intention to read in English and a strong belief that persistent reading in English in the long run will help improve their English. The results of this study confirm the educational values of incorporating ER into university English reading classes. The pedagogical implications for EFL instructors are described.

• Journal of Photoscience
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• v.5 no.1
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• pp.33-37
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• 1998

One macroscopic effect in the free-running Er:YAG laser is an accumulation of microscopic effects. Understanding of the exogenous water induced mechanical effect on the dental hard tissue by the Qswitched Er:YAG laser has an important impact on the further understanding of the free-running Er:YAG laser ablation on the dental hard tissue. The Q-switched Er:YAG laser (1-$\mu$s-long pulse width) was used in the recoil pressure measurement with an aid of water-jet system and a pressure transducer. The amplitude of the recoil pressure depends on the tooth surface conditions (dry and wet) and the volume of the water upon it. Wet surfaces yielded higher recoil pressure than that of dry, surface, and as the volume of the exogenous water drop increased, the amplitude of the recoil pressure increased also.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.2
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• pp.178-183
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• 2002

The effects of Dy$_2$O$_3$and Er$_2$O$_3$addition on the electromagnetic properties of Mn-Zn ferrite were investigated in the doping concentration range from 0.05 wt% to 0.25 wt%. All samples were prepared by standard fabrication of ferrite ceramics. The XRD patterns of sample were observed spinel and secondary phase. The densities of sample were showed nearly constant values. As the increased additive, electrical resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. Excess doped with Dy$_2$O$_3$ and Er$_2$O$_3$, those values decreased. The maximum electrical resistivity was observed with 0.15 we% and initial permeability was observed with 0.05 wt%. Magnetic loss decreased with additive and then increased in proportion to increased.

• The Journal of Internal Korean Medicine
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• v.39 no.6
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• pp.1281-1289
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• 2018

Objectives: This study is the first report on a case of subclinical hypothyroidism treated with Modified Er-Xian Decoction, which is rarely used in Korea. Methods: Patients were treated for 3 months with Modified Er-Xian Decoction and their therapeutic effects were evaluated through thyroid function tests and Spleen-Kidney deficiency Questionnaire. Results: Initial improvement was apparent after the administration of Modified Er-Xian Decoction. After 3 months of treatment, the patient 's Spleen-Kidney deficiency index improved significantly, and thyroid hormone levels returned to normal. Conclusions: In this case report, symptoms and biochemical improvement were confirmed based on a single herbal medicine prescription for subclinical hypothyroidism. It is necessary to verify the effect of this prescription through well - established clinical trials.

• Development and Reproduction
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• v.24 no.1
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• pp.31-41
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• 2020

We investigated the effects of endoplasmic reticulum (ER) stress inhibitor and antioxidant treatments during the micromanipulation of somatic cell nuclear transfer (SCNT) on in vitro development of SCNT embryos. Tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor and vitamin C (Vit. C), an antioxidant, were treated by alone or in combination, then, the level of X-box binding protein 1 (Xbp1) splicing and the expressions of ER stress-associated genes, oxidative stress-related genes, and apoptotic genes were confirmed in the 1-cell and blastocyst stages. In the 1-cell stage, the levels of Xbp1 splicing were significantly decreased in TUDCA and Vit. C treatment groups compared to the control (p<0.05). In addition, the expression levels of most ER stress-associated genes and oxidative stress-related genes were significantly lower in all treatment groups than the control (p<0.05), and the transcript levels of apoptotic genes were also significantly lower in all treatment groups than the control (p<0.05). In the blastocyst stage, decreased expression of ER stress-, oxidative stress-, and apoptosis-related genes were observed only in some treatments. However, the blastocyst formation rates in TUDCA and Vit. C treatment groups (24.8% and 22.0%, respectively) and mean blastocyst cell number in all treatment groups (59.7±4.3 to 63.5±3.3) were significantly higher (p<0.05) than those of control. The results showed that the TUDCA or Vit. C treatment during micromanipulation inhibited both ER and oxidative stresses in the early stage of SCNT embryos, thereby reducing cell damage and promoting in vitro development.

• Journal of Periodontal and Implant Science
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• v.44 no.5
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• pp.227-234
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• 2014

Purpose: Dentin hypersensitivity is a potential threat to oral health. Laser irradiation may provide reliable and reproducible treatment but remains controversial. The present study aimed to evaluate the effects of $CO_2$ or erbium-doped yttrium aluminium garnet (Er:YAG) laser therapy, and to assess mineral content. Methods: Eighteen human single-rooted teeth affected with advanced periodontitis were obtained. Buccal and lingual surfaces were planed to form 36 specimens. Ethylenediaminetetraacetic acid gel (24%) was applied to remove the smear layer and simulate hypersensitive teeth. The experimental groups were: group 1, control (no irradiation); group 2, $CO_2$ laser (repetitive pulsed mode, 2 W, $2.7J/cm^2$); and group 3, Er:YAG laser (slight contact mode, 40 mJ/pulse and 10 Hz). To evaluate dentinal tubule occlusion, six specimens per group (2-mm thickness) were prepared and observed using scanning electron microscopy (SEM) for calculation of the occlusion percentage. To evaluate the mineral content, six specimens per group (0.6-mm thickness) were used, and then the levels of Ca, K, Mg, Na, and P were measured by inductively coupled plasma-atomic emission spectrometry. In addition, the surface temperature of the specimens during laser irradiation was analyzed by a thermograph. Results: The SEM photomicrographs indicated melted areas around exposed dentinal tubules and a significantly greater percentage of tubular occlusion in the $CO_2$ and Er:YAG laser groups than the control, and in the Er:YAG group than the $CO_2$ laser group. In addition, no significant differences were noted among the experimental groups for the mineral elements analyzed. The $CO_2$ laser group showed an evident thermal effect compared to the Er:YAG group. Conclusions: $CO_2$ and Er:YAG laser are effective in treating dentin hypersensitivity and reducing its symptoms. However, the Er:YAG laser has a more significant effect; thus, it may constitute a useful conditioning item. Furthermore, neither $CO_2$ nor Er:YAG lasers affected the compositional structure of the mineral content.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.1
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• pp.116-133
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• 2001

Antifibrotic drugs could be delayed or inhibited massive collagen deposition in liver tissue or inhibited collagen synthesis. we investigated antifibrotic effects by several herbs(Schisnadra chinensis, Ganoderma japonicum, Sedum sarmentosum, Alisma canaliculatum, Plantago asiatica) extract with observations of collagen accumulation in liver tissue and collagen synthesis in sera. Rats were used for experimental animal that were devided 3 groups(sham control, BDL/S, BDL/S-ER). Rats were operated for inducing liver fibrosis(cirrhosis) by bile duct obstruction. Several herbs were prepared by water extraction and were applicated p. o. $3ml/day$ during 4 weeks. After observation period, rats were sacrificed and liver tissue and sera were collected. In result, the mortality of rats was 35% in BDL/S group and 20% in BDL/S-ER The color of bile juice in BDL/S-ER was bright yellow and murky yellow in BDL/S group. The significantly lower weight of liver($16.21g{\pm}5.3,\;20.58{\pm}2.4$) and spleen($1.96g{\pm}0.96,\;3.93{\pm}0.21$) were shown in BDL/S-ER than that of BDL/S(p<0.05) group. The value of collagen in liver tissue(25.7%) in BDL/S-ER was observed significantly lower than that of BDL/S group (Tab. 2). AST. ALT, ALP, t-bilirubin, BUN levels were low in BDL/S-ER as compared with those of BDL/S group, but the significance was not proven. The trichrome stained liver tissue in BDL/S-ER group was observed mild bile duct proliferation and fibrosis compared with BDL/S group. In conclusion, natural products inhibited new collagen synthesis and delayed massive collagen deposition in liver tissue, so that they have noticeable antifibrotic effects in experimental liver fibrosis(cirrhosis).

• Journal of Nutrition and Health
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• v.53 no.6
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• pp.583-595
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• 2020

Purpose: This study examined the effects of Sargassum horneri extracts on palmitic acid (PA)-induced endoplasmic reticulum (ER) stress in HepG2 cells. Methods: HepG2 cells were treated with varying concentrations of S. horneri extract or PA, and the cell viability was measured by water soluble tetrazolium salts analysis. The effective induction of ER stress and the effects of S. horneri were investigated through an examination of the ER stress-related genes, such as activating transcription factor 4 (ATF4), X-box binding protein (XBP1s), C/EBP homologous protein (CHOP), and 78-kDa glucose-regulated protein (GRP78) by quantitative reverse transcription polymerase chain reaction. The expression and activation levels of unfolded protein response (UPR) associated proteins, such as inositol-requiring enzyme-1α (IRE1α), eukaryotic translation initiation factor 2 alpha submit (eIF2α), and CHOP were examined by western blot analysis. Results: The treatment with PA increased the expression of UPR associated genes significantly and induced ER stress in a 12-hour treatment. Subsequent treatment with S. horneri reduced mRNA expression of ATF4, GRP78, and XBP1s. In addition, the protein levels of phosphate (p)-IRE1α, p-elF2α, and CHOP were also reduced by a treatment with S. horneri. An analysis of sirtuin (SIRT) mRNA expression in the S. horneri and PA-treated HepG2 cells showed that S. horneri increased the levels of SIRT2, SIRT6, and SIRT7, which indicates a possible role in reducing the expression of ER stress-related genes. Conclusion: These data indicate that S. horneri can exert an inhibitory effect on ER stress caused by PA and highlight its potential as an agent for managing various ER stress-related diseases.

• BMB Reports
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• v.51 no.8
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• pp.400-405
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• 2018

Chronic stress induces neuronal cell death, which can cause nervous system disorders including Parkinson's disease and Alzheimer's disease. In this study, we evaluated the neuroprotective effects of Clematis terniflora extract (CTE) against corticosterone-induced apoptosis in rat pheochromocytoma (PC12) cells, and also investigated the underlying molecular mechanisms. At concentrations of 300 and $500{\mu}g/ml$, CTE significantly decreased apoptotic cell death and mitochondrial damage induced by $200{\mu}M$ corticosterone. CTE decreased the expression levels of endoplasmic reticulum (ER) stress proteins GRP78, GADD153, and mitochondrial damage-related protein BAD, suggesting that it downregulates ER stress evoked by corticosterone. Furthermore, our results suggested that these protective effects were mediated by the upregulation of p-AKT and p-ERK1/2, which are involved in cell survival signaling. Collectively, our results indicate that CTE can lessen neural damage caused by chronic stress.