• Tribology and Lubricants
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• v.21 no.3
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• pp.142-148
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• 2005

In order to improve the fuel economy by design change of automatic transmission, various technologies such as increased shift stages, slip control of lock-up clutch and compact and low-weight design have been developed. And also many OEMs have developed their own ATFs as a part of these automatic transmissions. In this study, to investigate the effects of ATF characteristics on fuel economy, we got the worldwide OEM ATFs and made some reference fluids. And physical properties, frictional characteristics and fuel economy using dynamometer test for these fluids were evaluated. From the investigation, it was found that viscosities of ATFs are correlated with fuel economy in dynamometer test and reducing the viscosities made it possible to obtain fuel economy.

• YAKHAK HOEJI
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• v.51 no.4
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• pp.235-238
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• 2007

To determine the regulatory roles of phosphodiesterase (PDE) inhibitors on $PGE_2$-induced osteoclastogenesis, we investigated the effect of PDE inhibitors on osteoclast formation in the presence of $PGE_2$. Among PDE isozyme specific inhibitors, milrinone, a selective PDE3 inhibitor, and rolipram, a specific PDE4 inhibitor, increased $PGE_2$-induced osteoclast formation in cocultures of mouse bone marrow cells and osteoblasts. To verify that whether the PDE3 and PDE4 inhibitors act indirectly on osteoblasts, we measured the concentration of intracellular cAMP in osteoblasts. Treatment of milrinone or rolipram increased $PGE_2$-stimulated cAMP levels in osteoblasts. Furthermore, northern blot analysis revealed that the PDE3 and PDE4 inhibitors works synergistically with $PGE_2$ to increase the expression of TRANCE mRNA in osteoblasts. On the contrary, the PDE3 and PDE4 inhibitors did not augment the number of osteoclasts differentiated from bone marrow cells by $PGE_2$. In conclusion, the stimulation of $PGE_2$-induced osteoclast formation by the PDE3 and PDE4 inhibitors are attributable to their indirect effect on osteoblasts, not to their direct effect on bone marrow-derived osteoclast precursors.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.111-121
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• 2010

In order to investigate the preliminary repeat oral dose toxicity and to determine the highest dosage for further 4-week repeated dose toxicity test, Low Molecular Weight Fucoidan (LMF) has been showed various pharmacological effects, was orally administered to female and male rats, once a day for 14 days at dose levels of 2,000, 1,000, 500 and 0 (vehicle control) mg/kg (body weights) in a volume of 10 ml/kg. The mortality and changes on the body weights, clinical signs, hematology, serum biochemistry and gross observations were monitored with organ weight and histopathology of principle organs. As the results of 14-day repeated oral treatment of LMF, no LMF treatment related mortalities were detected up to 2,000 mg/kg in both male and female rats, respectively. In addition, no noticeable changes on the body weight and clinical signs were detected except for significant decreases on the body weights and gains restricted to male 2,000 mg/kg treated groups as compared with male vehicle control. No meaningful changes on the organ weights, hematological, serum biochemistrical, gross and histopathological findings were observed. Therefore the highest dosage in the 4-week repeated dose toxicity test is suggested as 2,000 mg/kg in both female and male rats, respectively.

• Korean Journal of Applied Biomechanics
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• v.33 no.2
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• pp.62-72
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• 2023

Objective: Although balance training has been used as an effective ankle injury rehabilitation program to restore neuromuscular deficits in patients with chronic ankle instability, it is not effectively used in terms of motor learning. Attentional focusing can be an effective method for improving ankle kinematics to prevent recurrent ankle injuries. This study aimed to 1) evaluate the effects of attentional focus, including internal and external focus, and 2) determine a more effective focusing method for patients with chronic ankle instability to learn balance tasks. Method: Twenty-four patients with chronic ankle instability were randomly assigned to three groups (external focus, internal focus, and no feedback) and underwent four weeks of progressive balance training. The three-dimensional ankle kinematics of each patient were measured before and after training as the main outcomes. Ensemble curve analysis, discrete point analysis, and post hoc pairwise comparisons were performed to identify interactions between groups and time. Results: The results showed that (1) the external focus group was more dorsiflexed and everted than the internal focus group; (2) the external focus group was more dorsiflexed than the no feedback group; and (3) the no feedback group was more dorsiflexed than the internal focus group. Conclusion: Because dorsiflexion and eversion are ankle motions that oppose the mechanism of lateral ankle sprain, using the external focus method during balance training may be more effective in modifying these motions, thereby reducing the risk of ankle sprain.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.201-204
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• 2002

This study was undertaken to find effects of ethanol extracts from Bombyx mori on the hyperglycemia induced by streptozotocin in rats. Blood glucose level of rats increased depending on experimental days after streptozotocin treatment. But there was no difference in blood glucose level between the rats injected with ethanol extracts of B. mori and normal rats. There was no significant difference in the kidney fibrosis between the rats injected with ethanol extrscts of B. mori and normal rats at all ages examined. The transforming growth factor-$\beta$l ($TGF-{\beta}1$) protein was detected in the glomerulay endothelial cells and tubular epithelial cells of streptozotocin rats at 14 days of age. In the rats injected with ethanol extracts of B. mori to the kidneys, the $TGF-{\beta}1$ protein was detected very faintly. The $TGF-{\beta}1$ mRNA of streptozotocin rats increased at 14 days of age, and this was higher than the rats injected with ethanol extrscts of B. mori. Taken these together, the results suggest that the ethanol extracts of B. mori ameliorate hyperglycemia of the rats induced by streptozotocin.

• Toxicological Research
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• v.24 no.1
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• pp.11-15
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• 2008

In this research the genotoxic effect of $Polycan^{TM}$ ${\beta}$-glucans originated from Aureobasidium pullulans SM-2001, was evaluated using the mouse micronucleus test. $Polycan^{TM}$ was administered once a day for 2 days by oral gavage to male ICR mice at doses of 1000, 500 and 250 mg/kg. Cyclophosphamide was used as a known genotoxic agent in a positive control group. The appearance of a micronucleus is used as an index for genotoxic potential. The results obtained indicated that $Polycan^{TM}$ shows no genotoxicity effect up to 1000 mg/kg dosing levels. In addition, it is also considered that there were no problems from cytotoxicity of $Polycan^{TM}$ tested in this study because the polychromatic erythrocyte ratio was detected as > 0.47 in all tested groups.

• Toxicological Research
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• v.25 no.4
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• pp.225-230
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• 2009

The genotoxic effects of DHU001, a polyherbal formula were evaluated using the mouse micronucleus test. DHU001 was administered once a day for 2 continuous days by oral gavage to male ICR mice at doses of 2000, 1000 and 500 mg/kg. Cyclophosphamide was used as a known genotoxic agent in a positive control. The appearance of a micronucleus is used as an index for genotoxic potential. In addition, the changes on the total white blood cells and differential counts on the lymphocytes, neutrophils, eosinophils, basophils and monocytes in the prepared blood smears were also conducted to observe the possible immunosuppression. The results indicats that DHU001 showed no genotoxicity effects up to 2000 mg/kg dosing levels and did not influenced on the total white blood cells and differential counts. In addition, it is also considered that there were no problems from cytotoxicity of DHU001 tested in this study because the polychromatic erythrocyte ratio was detected as > 0.41 in all tested groups.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.1
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• pp.89-98
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• 2003

Titanium requires special ceramic system for veneering. Low fusing dental ceramics with coefficients of thermal expansion matching that of titanium have been developed. The purpose of this study was determine the bond strengths between cast and noncast pure titanium and two commercial titanium porcelains, and to compare the results with a conventional nickel-chromium alloy-ceramic system. The bond strengths were determined using a 3-point flexure test. Three-point flexure specimens $25{\times}3{\times}0.5mm$ were prepared After removal of ${\alpha}-case$ layer, they were veneered with $8{\times}3{\times}1mm$ of ceramics at the center of the bar. Specimens were tested in a universal testing machine. Within the limits of this study, the following conclusions were drawn: 1. The bond strengths between pure titanium and two commercial porcelains exceeded th lower limit of the bonding strength value in ISO 9693(25MPa). 2. There was no significant difference between cast and noncast titanium-porcelain bonds. 3. There was no significant difference between two commercial titanium porcelains. 4. The bond strengths of the titanium-porcelain systems ranged from 73% to 79% of that of the Ni-Cr-conventional porcelain system.

• Toxicological Research
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• v.24 no.3
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• pp.213-218
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• 2008

In this research, the genotoxic effects of Kong-Jin-Dan(KJD), a polyherbal formula were evaluated using the mouse micronucleus test. KJD was administered once a day for 2 continuous days by oral gavage to male ICR mice at doses of 2000, 1000 and 500 mg/kg. Cyclophosphamide was used as a known genotoxic agent in a positive control. The appearance of a micronucleus is used as an index for genotoxic potential. In addition, the changes on the total white blood cells and differential counts on the lymphocytes, neutrophils, eosinophils, basophils and monocytes in the prepared blood smears were also conducted to observe the possible immunosuppress. The results obtained indicated that KJD shows no genotoxicity effects up to 2000 mg/kg dosing levels, but KJD shows slight increased trends in the blood total leukocyte numbers as pharmacological effects of immune stimulation. In addition, it is also considered that there were no problems from cytotoxicity of KJD tested in this study because the polychromatic erythrocyte ratio was detected as > 0.42 in all tested groups.

• Journal of Power Electronics
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• v.6 no.2
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• pp.131-138
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• 2006

An active clamp ZVS PWM forward converter using a secondary synchronous switch control is proposed in this paper. The proposed converter is suitable for low-voltage and high-current applications. The structure of the proposed converter is the same as a conventional active clamp forward converter. However, since it controls the secondary synchronous switch to build up the primary current during a very short period of time, the ZVS operation is easily achieved without any additional conduction losses of magnetizing current in the transformer and clamp circuit. Furthermore, there are no additional circuits required for the ZVS operation of power switches. Therefore, the proposed converter can achieve high efficiency with low EMI noise, resulting from soft switching without any additional conduction losses, and shows high power dens~ty, a result of high efficiency, and requires no additional components. The operational principle and design example are presented. Experimental results demonstrate that the proposed converter can achieve an excellent ZVS performance throughout all load conditions and demonstrates significant improvement in efficiency for the 100W (5V, 20A) prototype converter.