• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.142-145
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• 2013

The upconversion (UC) luminescence of $Li^+/Er^{3+}/Yb^{3+}$ co-doped $CaWO_4$ phosphors and effects of $Yb^{3+}$ concentration are investigated in detail. Single crystallized $CaWO_4$ : $Li^+/Er^{3+}/Yb^{3+}$ phosphor can be obtained, co-doped up to 35.0/5.0/30.0 mol% ($Li^+/Er^{3+}/Yb^{3+}$) by solid-state reaction. Under 980 nm excitation, $CaWO_4$ : $Li^+/Er^{3+}/Yb^{3+}$ phosphor exhibited strong green UC emissions visible to the naked eye at 530 and 550 nm induced by the intra 4f transitions of $Er^{3+}$ ($^4H_{11/2}$, $^4S_{3/2}{\rightarrow}^4I_{15/2}$). The optimum doping concentrations of $Yb^{3+}$ that would result in the highest UC luminescence were determined, and a possible UC mechanism that depends on the pumping power is discussed in detail.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.95-100
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• 2003

Dichlorodiphenyltrichloroethane (DDT), is a widespread environmental pollutant. In this study, we investigated the effect of DDT on testosterone production through aromatase and investigated its molecular mechanism in testicular leydig cell, R2C. We investigated that the effects of DDT on testosterone production and its effects on aromatase activity in R2C cell by radio immunoassay (RIA). As the results, the potent leyding cell activator LH increased testosterone production compared to the control. DDT exposure significantly decreased testosterone production in R2C cell and DDT alone affected T reduction in a dose-dependent manner in R2C cell slightly. In addition, DDT was found to increase aromatase activity in R2C cell in a dose dependent manner. In order to assess whether the suppressive effects of DDT on LH-inducible testosterone production might be influenced by the ER, ICI 182.780, a pure antiestrogen, was used, and it was found that these inhibitory effects of DDT were antagonized by ICI 182.780, implying that the ER mediates the suppressive effects of DDT. Furthermore, the inducible effects of DDT on aromatase might be influenced by the ER, ICI 182.780 was used, and it was found that these enhancing effects of DDT were antagonized by ICI 182.780, implying that the ER mediates the inducible effects of DDT. Our results indicated that DDT inhibition of LH-inducible testosterone production in R2C is mediated through aromatase. However, the precise mechanisms by which DDT enhance in leyding cell remains unknown. The current study suggests the possibility that DDT might act as a modulator aromatase gene transcription.

• 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.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.235-241
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• 2011

The anti-hyperlipidemic effects of dietary supplementation with sea tangle Laminaria japonica were investigated using an animal model in which normal rats were fed either sea tangle, sea tangle ethanol extract (EE-ST) and sea tangle extracted residue (ER-ST). Total lipid and triglyceride levels in the serum were significantly (P < 0.05) reduced in rats fed ER-ST at a dose of 200 mg/kg body weight when compared to hyperlipidemic control rats. Significant decreases in serum total cholesterol and low density lipoprotein-cholesterol levels also occurred in rats fed ER-ST at 200 mg/kg body weight. In addition, the atherosclerosis index and superoxide dismutase in blood lipids were significantly (P < 0.05) lowered in rats fed ER-ST at 200 mg/kg body weight as compared to control rats. In conclusion, sea tangle and ER-ST exhibited beneficial anti-hyperlipidemic and anti-arteriosclerosis effects.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.308-312
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• 2003

Various pesticides known or suspected to interfere with steroid hormone function were screened toy effects in leydig cells on catalytic activity and mRNA expression of aromatase. Dichlorodiphenyltrichloroethane (DDT) is a widespread environmental pollutant. In this study, we investigated the effect of DDT on testosterone production through aromatase activity and its molecular mechanism in testicular leydig cell, R2C by using radioimmunoassay (RIA). As the results, the potent leydig: cell activator LH increased testosterone production compared to the control. DDT exposure significantly decreased testosterone production in R2C cell. In addition, DDT was found to increase aromatase gene expression and activity in R2C cell in a dose dependent manner. In order to assess whether the suppressive effects of DDT on LH-inducible testosterone (T) production might be influenced by the ER, ICI 182.780 was used, and it was found that these inhibitory effects of DDT were antagonized by ICI 182.780, implying that the estrogen receptor (ER) mediates the suppressive effects of DDT. Furthermore, the inducible effects of DDT on aromatase gene expression might be influenced by the ER, ICI 182.780 was used, and it was found that these enhancing effects of DDT were antagonized by ICI 182.780, implying that the ER mediates the inducible effects of DDT. Our results indicated that DDT inhibition of luteinizing hormone (LH) -inducible T production in R2C cell is mediated through aromatase. However, the precise mechanisms by which DDT enhance in R2C cell remains unknown. The current study suggests the possibility that DDT might act as a modulator aromatase gene transcription.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1365-1375
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• 2005

The antiestrogenic effects of marijuana smoke condensate (MSC) and three major cannabinoids, i.e., $\bigtriangleup^{9}$-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN), were evaluated using in vitro bioassays, viz., the human breast cancer cell proliferation assay, the recombinant human estrogen receptor (ER) competitive binding assay, and the reporter gene assay. The inhibitory effects on estrogen were also examined using the ethoxyresorufin-O­deethylase (EROD) assay, the aromatase assay, and the 17$\beta$-estradiol ($E_{2}$) metabolism assay. The results showed that MSC induced the antiestrogenic effect via the ER-mediated pathway, while THC, CBD, and CBN did not have any antiestrogenic activity. This suggests that the combined effects of the marijuana smoke components are responsible for the antiestrogenicity of marijuana use. In addition, MSC induced the CYP1A activity and the $E_{2}$ metabolism, but inhibited the aromatase activity, suggesting that the antiestrogenic activity of MSC is also related to the indirect ER-dependent pathway, as a result of the depletion of the in situ $E_{2}$ level available to bind to the ER. In conclusion, pyrogenic products including polycyclic aromatic hydrocarbons (PAHs) in the non-polar fraction, which is the most biologically active fraction among the seven fractions of MSC, might be responsible for the antiestrogenic effect.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.451-456
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• 2002

This paper describes the properties of Temperature-Viscosity characteristics of hydrous and anhydrous ER fluids containing starch and titanium particle in silicone oil. ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed in the electrically insulating silicone oil induced when electric field is applied. ER fluids under electric field have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured on the couette cell type rheometer as a function of electric fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electric field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200/equation omitted/ in 2 minutes.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.434-440
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• 2004

The electro-rheological fluids for semi-active suspension system are a class of colloidal dispersion which exhibit large reversible changes in their rheological behavior when they are subjected to external electrical fields. This paper presents Bingham properties of ER fluids subjected to temperature variations. In addition, an appropriate size of the ER damper for a passenger car is proposed to investigate the effects of Bingham characteristics on the damping performance. The filed-dependent damping forces are evaluated according to the temperature variation and sedimentation ratio.

• Korean Journal of Materials Research
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• v.16 no.1
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• pp.58-62
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• 2006

Effects of doping concentration and annealing atmosphere on the luminescent properties of $Er^{3+}$ doped ZnO phosphor powders were investigated. Photoluminescence (PL) spectra of ZnO:Er exhibit an orange emission band at around 575 nm, while those of pure ZnO show a green emission at 520 nm. Emission difference between ZnO:Er and pure ZnO is attributed to the energy transfer of Er ions in ZnO. The highest PL intensity is obtained by doping 1 mol% Er to ZnO. Luminescent properties of ZnO:Er phosphors annealed at $N_2$+vacuum atmosphere are superior to those annealed at $N_2$ atmosphere.

• Molecules and Cells
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• v.41 no.12
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• pp.1000-1007
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• 2018

Mitochondria and endoplasmic reticulum (ER) are essential organelles in eukaryotic cells, which play key roles in various biological pathways. Mitochondria are responsible for ATP production, maintenance of $Ca^{2+}$ homeostasis and regulation of apoptosis, while ER is involved in protein folding, lipid metabolism as well as $Ca^{2+}$ homeostasis. These organelles have their own functions, but they also communicate via mitochondrial-associated ER membrane (MAM) to provide another level of regulations in energy production, lipid process, $Ca^{2+}$ buffering, and apoptosis. Hence, defects in MAM alter cell survival and death. Here, we review components forming the molecular junctions of MAM and how MAM regulates cellular functions. Furthermore, we discuss the effects of impaired ER-mitochondrial communication in various neurodegenerative diseases.