• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.67-72
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• 2004

Electro-Rheological(ER) fluids consist of suspensions of fine polarizable particles In a dielectric oil, which upon application of an external electric field control take on the characteristics of the Bingham solid. In this study, the temperature dependence of the viscosity was Investigated for an ER fluid consisting of 35 weight % of zeolite particles in hydraulic oil 46cSt. Thermal activation analysis was performed by changing the ER fluid's temperature from $-10^{\circ}C$ to $50^{\circ}C$. According to the analysis, the activation energy for flow of the ER fluid was 79.6 kJ/mole without applying electric field. On the other hand, with the electric field of 2kV/mm, the linearity between viscosity and temperature was not existed By changing the temperatures the viscosity (or shear stress) versus shear rates were measured. In this experiment shear rates were increased from 0 to $200s^{-1}$ in 2 minutes. Generally, the hydraulic oil 46cSt will be operated at the temperature of about $40^{\circ}C$, thus, the ER fluid's electric field dependence of viscosity was examined at this temperature. Also, an influence of adding the dispersant(Carbopl 940) on ER effect was discussed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.137-137
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• 2003

Optical amplificator have been used to compensate the losses in the optical signal transmission and processing. Today, there has been increasing demand for the very low cost optical amplifier. Sol-gel offers considerable potential both low cost manufacture, and for great flexibility in materials composition and structure. In addition, the sol-gel process is a very attractive method for producing porous materials with controlled structure. In this work, we present the potoluminescence properties of Er doped A1$_2$O$_3$/SiO$_2$ films. Erbium doped alumina nano sol was prepared by Al(NO$_3$)$_3$.9$H_2O$ and Er(NO$_3$)$_3$.5$H_2O$ through hydrolysis and peptization, and then GPS (3-Glycidoxypropyltrimethoxysilane) was added into Er doped alumina nano sol for organic- inorganic hybridization. Er doped A1$_2$O$_3$/SiO$_2$ film was obtained by spin coating, dip coating and thermal treatment from 30$0^{\circ}C$~120$0^{\circ}C$, and there were crack-free after thermal treatment. The thickness of film was measured SEM, and the porosity of film was characterized by BET and TGA. The crystal phase of Er doped A1$_2$O$_3$/SiO$_2$ were determined by XRD. Finally, the photoluminescence properties of Er doped A1$_2$O$_3$/SiO$_2$ films will be discuss with the consideration of porosity and crystallity.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.136-136
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• 2003

In fiber optic networks, system size and cost can be significantly reduced by development of optical components through planar optical waveguides. One important step to realize the compact optical devices is to develop planar optical amplifier to compensate the losses in splitter or other components. Planar amplifier provides optical gain in devices less than tens of centimeters long, as opposed to fiber amplifiers with lengths of typically tens of meters. To achieve the same amount of gain between the planar and fiber optical amplifier, much higher Er doping levels responsible for the gain than in the fiber amplifier are required due to the reduced path length. These doping must be done without the loss of homogeniety to minimize Er ion-ion interactions which reduce gain by co-operative upconversion. Sol-gel process has become a feasible method to allow the incorporation of Er ion concentrations higher than conventional glass melting methods. In this work, Er-doped $SiO_2$-A1$_2$ $O_3$ films were prepared by two different method via sol -Eel process. Tetraethylorthosilicate(TEOS)/aluminum secondary butoxide [Al (OC$_4$ $H_{9}$)$_3$], methacryloxypropylcnethoxysaane(MPTS)/aluminum secondary butofde [Al(OC$_4$ $H_{9}$)$_3$] systems were used as starting materials for hosting Er ions. Er-doped $SiO_2$-A1$_2$ $O_3$ films obtahed after heat-treating, coatings on Si substrate were characterized by X-ray din action, FT-IR, and N-IR fluorescence spectroscopy. The luminescence properties for two different processing procedure will be compared and discussed from peak intensity and life time.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.190-195
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• 2000

The electrical properties and stability of ZPCE varistors consisted of $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ ceramics were investigated. $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ based ceramics were sintered at $1300^{\circ}C$ and $1350^{\circ}C$, respectively, without and with 0.5 mol% $Er_2O_3$. The varistors sintered at $1300^{\circ}C$ exhibited a better nonlinearity than that $1350^{\circ}C$. The varistors with $Er_2O_3$ of 0.5 mol% exhibited a high nonlinear exponent of 52.8. However, they easily degraded due to the low density below 85% of TD. On the other hand, the varistors sintered at $1350^{\circ}C$ without $Er_2O_3$ exhibited an extremely poor nonlinearity, but the varistors with $Er_2O_3$ of 0.5 mol% exhibited a relatively good nonlinearity, which the nonlinear exponent is 34.8 and the leakage current is $7.4\;{\mu}A$ Morever, they exhibited a very high stability, which the variation rate of varistor voltage, nonlinear exponent, and leakage current are -0.9%, -2.9%, and +2.7%, respectively, under the third stress $(0.80 V_{1mA}/90^{\circ}C/12h)$ + $(0.85 V_{1mA}/115^{\circ}C/12h)$ + $(0.90 V_{1mA}/120^{\circ}C/12h)$. Consequently, it was estimated that $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ ceramics will be usefully applied to develop the advanced $Pr_6O_{11}$-based ZnO varistors.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3881-3885
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• 2015

Obesity markedly increases the risk of colorectal cancer. Recently, the preventive effects of edible mushrooms on triglyceride elevation and visceral fat accumulation have been reported. Here, the effects of Pleurotus eryngii (Eringi) and Hypsizygus marmoreus (Bunashimeji) on azoxymethane (AOM)-induced aberrant crypt foci (ACF; precancerous lesions) in the colorectums of mice fed a high-fat diet were examined. Eringi (ER) and Bunashimeji (BU) mushroom powder samples were used. Six-week-old male C57BL/6J mice received an intraperitoneal injection of AOM (10 mg/kg) once a week for two weeks, and were sacrificed and dissected at 6 weeks after the start of the experiment. After the initiation of the experiment, they received a normal diet (ND), high-fat diet (HFD), HFD + ER (1 or 5% of diet), or HFD + BU (1 or 5% of diet). As a result, body and fat weights were significantly lower in the 5% ER and BU groups than in the HFD group. Liver triglyceride levels were also significantly lower in the 5% ER and BU groups. Total liver cholesterol levels were significantly lower in the 5% ER group. The numbers of ACF (especially large ACF) showed strong inhibitory effects in both ER and BU groups. Measurement of the cell proliferation marker Ki-67 labeling index in the colonic mucosa demonstrated more significant suppression in both ER and BU groups than in the HFD group. These results suggest that the simultaneous intake of ER and BU may inhibit colorectal tumorigenesis in HFD-fed mice.

• Journal of Korean Biological Nursing Science
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• v.1 no.1
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• pp.86-99
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• 1999

The purpose of this study is to find out the difference in circadian rhythm and level of fatigue between ER and General Ward Nurse. This study was done through analyzing body temperature, heart rate and major electrolytes such as $Na^+$ and $K^+$ concentration on urinalysis, which are related to factors of circadian rhythm and level of fatigue. The subjects, 17 nurses from Emergency Room and 25 nurses from general ward, were selected from a General Hospital in Taegu City on August 8 to 23, 1998. And the data were analyzed by proportion, t-test, chi-square and Pearson's Correlation, ANCOVA, using SAS program. The results of this study were shown as follows: First, The difference of Maximal and minimal heart rate was significant between ER group and general ward group. However, body temperature difference wasn't notable. Second, Urine $Na^+$ concentration on urinalysis was lower and $K^+$ concentration on urinalysis was higher in ER group than general ward group significantly. Third, Fatigue level was higher in ER group than general ward group significantly. Fourth, through urine concentration, significant relations in circadian rhythm of ER nurse group and general ward group and their fatigue level were found. Urine $Na^+$ concentration on urinalysis of ER nurse was significant related with their fatigue level. In conclusion, the effect of fatigue on circadian rhythm is greater in ER group than general ward group during night shift. This study could be a help in improvement of nurse's health and understanding the effect of fatigue on health.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8789-8791
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• 2014

Estrogen receptor alpha ($ER{\alpha}$) is one of the major sub-types of estrogen receptors. $ER{\alpha}$ plays an important role in cellular proliferation and differentiation, chiefly in mammary tissues. In the present study we aimed to quantify of $ER{\alpha}$ mRNA and protein expression in breast tissues from the Iranian population using a real-time PCR assay. Twenty nine breast tissues including 19 adenocarcinomas and 10 normal controls were recruited from the Iranian population. mRNA extraction and cDNA synthesis were performed from these tissues using commercial kits. $ER{\alpha}$ mRNA and protein expression was quantified using real-time PCR and immunohistochemistry respectively. The results showed high expression of $ER{\alpha}$ mRNA (68%) and protein (53%) in the majority of breast cancer tissues compared to normal breast tissues (p= 0.035). Also, high $ER{\alpha}$ mRNA was associated with tumour size of breast carcinomas. In this study, we first reported the expression of $ER{\alpha}$ in Iranian patients with breast cancers and demonstrated prevalence of the expression to be similar to breast cancers noted in other populations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.335-335
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• 2008

Phosphate glass samples with various $Cr_2O_3$ and $Er_2O_3$ contents based upon $55P_2O_5\cdot24BaO\cdot10K_2O\cdot4Al_2O_3\cdot6Yb_2O_3$ were prepared. The prepared glass compositions are dehydrated using gas bubble flow method in open system and investigated the effects of the eliminating of OH groups from the glass melts with bubbling time. It was found that the probability of $Er^{+3}$ fluorescence quenching by OH groups oscillations linear depends upon the OH groups absorption coefficients in the maximum of the stretch vibrations band at $3500cm^{-1}$ while $Er^{+3}$ concentration range is between $1.6\times10^{19}$ and $21.2\times10^{19}$ ion/$cm^3$.