• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1119-1126
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• 2000

This paper is concerned with the design and application of an Electro-Rheological(ER) fluid damper to suppress the vibration of a rotor system. The system is flexible with a slender shaft and a thin disk, being supported by two ball bearings. In addition, to investigate the system performances also in the high speed range, the driving torque is made transmit through a speed increasing gear train. Along with the experiments, to predict and compare the ER damper effect, the rotor system is simulated as to its free and forced vibration characteristics by means of a finite element method code, which is assembled with the mathematical model of the designed ER damper.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1368-1378
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• 2009

Unfolded protein response (UPR) is an important genomic response to endoplasmic reticulum (ER) stress. The ER response is characterized by changes in specific proteins, induction of ER chaperones and degradation of misfolded proteins. Also, the pathogenesis of several diseases like Alzheimer's disease, neuronal degenerative diseases, and diabetes reveal the role of ER stress as one of the causative mechanisms. Borneolum has been used for neuronal disease in oriental medicine. In the present study, the protective effect of borneolum on thapsigargin-induced apoptosis in rat C6 glial cells. Treatment with C6 glial cells with 5 uM thapsigargin caused the loss of cell viability, and morphological change, which was associated with the elevation of intracellular $Ca^{++}$ level, the increase in Grp78 and CHOP and cleavage of pro-caspase 12 Furthermore, thapsigargin induced Grp98, XBP1, and ATF4 protein expression in C6 glial cells. Borneolum reduced thapsigargin-induced apoptosis through ER pathways. In the ER pathway, borneolum attenuated thapsigargin-induced elevations in Grp78, CHOP, ATF4, and XBP1 as well as reductions in pro-caspase 12 levels. Also, our data showed that borneolum protected thapsigargin-induced cytotoxicity in astrocytes from rat (P3) brain. Taken together, our data suggest that borneolum is neuroprotective against thapsigargin-induced ER stress in C6 glial cells and astrocytes. Accordingly, borneolum may be therapeutically useful for the treatment of thapsigargin-induced apoptosis in central nervous system.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.439-447
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• 2003

This was performed to evaluate the inhibitory effect of laser on the growth of S. mutans. The bacterial pallets containing S. mutans KCTC 3065 were irradiated with Er:YAG laser and Nd :YAG laser by non-contact method at an intensity of 50mJ for 5 sec with the pulse repetition rates of 10Hz and 30Hz, respectively. The following results were obtained on colony count, acid producing ability, and the amount of insoluble extracellular polysaccharide synthesis. 1. The irradiation of Nd:YAG laser after photosensitization with Chinese ink inhibited the proliferation of S. mutans the most, and the irradiation of Er:YAG also inhibited the proliferation. However, the irradiation of Nd:YAG laser alone could not inhibited the proliferation of S. mutans. The pulse repetition rate did not affect significantly on the proliferation of bacteria in overall. 2. The irradiation of Nd:YAG laser after the photosensitization with Chinese ink inhibited the acid production of S. mutans the most for a certain period of time. Er:YAG laser also inhibited acid production. When Nd:YAG laser was used alone, the acid production of S. mutans was not been inhibited. The irradiation of Nd:YAG laser after photosensitization with Chinese ink inhibited the acid production ability of bacteria the most as the pulse repetition rate increased. 3. Laser irradiation did not inhibited the synthesis of insoluble extracellular polysaccharide of S. mutans. From these results, we conclude that the irradiation of Er:YAG laser and Nd:YAG laser after photosensitization with Chinese ink would inhibit the proliferation and acid production by S. mutans, which may prevent dental caries. However, this effect does not last long time so that the laser irradiation should be repeated frequently in order to obtain clinical effect; thus, this laser irradiation would not have a clinical usefulness in preventing dental caries when used solely.

• Korean Journal of Materials Research
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• v.3 no.2
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• pp.185-192
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• 1993

Abstract Electrorheological effect on the dispersive system of polarizable fine powder/dielectric oil has been investigated. ER effect was explained divided into following 3 mechanisms; (1) surface conductance, (2) bulk conductance, and (3) induced polarization. Mathematical model which predicts the interactive force between two fine particles in the electrorheological fluid has been introduced based on the induced polarization mechanism. This model may provide guide to select materials for strong ER effect. The attractive force between two particles was calculated using the above model for the selected 7 materials such as ceramics, ferrites, polymers etc. From the calculation result, it was found that the ceramics and ferrites are good materials which show a strong ER effect.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.585-594
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• 2020

At present, aging-related degenerative muscle diseases are considered a serious problem. However, the drug effect on the treatment and prevention of sarcopenia has not been investigated. The purpose of this study was to evaluate the value of extract of Pu'er tea as a remedy to alleviate the symptoms of sarcopenia. Pu'er tea extracts showed excellent radical scavenging ability. The expression of Myh3 was promoted and myotube formation also was increased by treatment of Pu'er tea extracts. These results suggest that Pu'er tea is a natural substance that promotes myogenesis, and is valuable as a material for pharmaceutical research on the prevention and treatment of various muscle diseases, including sarcopenia. And It is necessary to confirm specific indicator substances of puer tea and further study on this.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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• pp.1-5
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• 2000

Optical and electrical properties of GaSe:Er\ulcorner single crystals grown by the Bridgenman technique have been investigated by using optical absorption and h\Hall-effect measurement system. The Hall coefficients were mea-sured by using a high impedance electrometer in the temperature range from 360K to 150K. The temperature dependence of hole concentration show the characteristic of a partially compensated p-type semiconductor. Carrier density(N\ulcorner) of GaSe doped with Erbium was measured about 3.25$\times$10\ulcorner [cm\ulcorner] at temperature 300K, which was higher than undoped specimen. Photon energy gap (E\ulcorner) of GaSe:Er\ulcorner specimen was measured about 1.79eV.

• Journal of Life Science
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• v.13 no.3
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• pp.314-323
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• 2003

The purpose of this study was to examine the effects of xenobiotic nuclear receptors, CAR, SXR, and PPAR${\gamma}$ on the transcriptional activity of estrogen receptor in human breast cancer cell lines and compare with those in human hepatoma cell line. Two different breast cancer cell lines, MCF-7 and MDA-MB-231 were cultured and effects of CAR, SXR, and PPAR${\gamma}$ on the ER-mediated transcriptional activation of synthetic (4ERE)-tk-luciferase reporter gene were analyzed. Consistent with the previous report, CAR significantly inhibited ER-mediated transactivation and SXR repressed modestly whereas the PPAR${\gamma}$ did not repress the ER-mediated transactivation. However, in breast cancer cells neither of the xenobiotic receptors repressed the ER-mediated transactivation. Instead, they tend to increase the transactivation depending on the cell type and xenobiotic nuclear receptors. In MCF-7, SXR but neither CAR nor PPAR${\gamma}$ slightly increased ER-mediated transactivation whereas in MDA-MB-231, CAR and PPAR${\gamma}$ but not SXR tend to increase the transactivation of the reporter gene. These results indicate that the effects of ER cross-talk by the CAR, SXR, and PPAR${\gamma}$ , are different in breast cancer cells from hepatoma cells. In conclusion, the transcriptional regulation by estrogen can involve different cross-talk interaction between estrogen receptor and xenobiotic nuclear receptors depending on the estrogen target cells.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.3
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• pp.223-228
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• 2007

This paper investigated on mechanical characteristic of Al alloy for ship's welded with various welding techniques such as TIG, MIG welding and welding by robot. The yield strength, tensile strength and elongation in TIG welding present 83.9%, 64.6% and 21.9% compare to those in base metal, respectively. The MIG welding is carried out with welding eletrode of ER5183 and ER5356. The mechanical characteristics in ER5356 are improved at approximately 2-4% for ER5183. The mechanical properties of 5083O in welding by robot are better than those of 5456-H116.

• Development and Reproduction
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• v.10 no.4
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• pp.255-261
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• 2006

Although some phytoes rogens might have beneficiary rather than adverse effects, most endocrine disrupting compounds(EDCs) are considered to be harmful to human and wildlife health through interfering the endocrine system. Previously we found that prepubertal exposure to genistein(GS), a well-known isoflavone phytoestrogen, could activate the reproductive system of immature female rats resulting precocious puberty. Interestingly, di(2-ethyl hexyl) phthalate(DEHP) exposure brought inverse result, a delayed puberty, in the same experimental regimen. In this study, we examined whether prepubertal exposure to GS or DEHP affect the gene expressions of estrogen receptors($ER\;{\alpha}$ and $ER\;{\beta}$) and LH receptor(LHR) which represent the maturational status of ovary and uterus in immature rats. GS (100 mg/kg/day) was administered daily from postnatal day 25 to the day when the first vaginal opening(VO) was observed, and the animals were sacrificed on the next day(day 32). Similarly, DEHP(l00 mg/kg/day) was administered daily from postnatal day 25 through the day when the first V.O. in control group was observed, and the animals were sacrificed on the next day(day 36). To determine the transcriptional changes in the hormone receptors, total RNAs were extracted from ovary and uterus and were applied to semi-quantitative reverse transcription polymerase chain reaction(RT-PCR). In the GS group, the transcriptional activities of $ER\;{\alpha}$, $ER\;{\beta}$ and LHR in uterus and LHR in ovary were significantly increased when compared to those of control group. In the DEHP group, the transcriptional activities of all the hormone receptors measured were significantly lowered when compared to those of control group. These alteration of the reproductive hormone receptor expressions in ovary and uterus might be represent the phenotypic aspects(secondary sexual characteristics) such as tissue weights and reproductive hormone levels during perinatal period in immature female rats.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.173-177
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• 2010

Thermal stabilizing effect of $Yb^{3+},\;Er^{3+}$ codoping into $TiO_2$ powder prepared by sol-gel method and its upconversion characteristics were analyzed. The effect of $TiO_2:Yb^{3+},\;Er^{3+}$ ions on crystallinity and phase transition was studied by X-ray diffraction (XRD). The change of band-gap energy induced from Yb and Er codoping was analyzed by UV-Vis. The band-gap energy of $TiO_2$ have been slightly narrowed by $Yb^{3+},\;Er^{3+}$ codoping, which indicated that the $Yb^{3+},\;Er^{3+}$ ions can enhance the photo-catalytic property of $TiO_2$. green and red up-conversions of $Yb^{3+}$ and $Er^{3+}$ co-doped $Y_2O_3:Yb^{3+},\;Er^{3+}$ phosphor were analyzed by PL equipped with 980 nm laser.