• Journal of Dental Rehabilitation and Applied Science
• /
• v.28 no.2
• /
• pp.147-161
• /
• 2012

This study is to assess the effect of horizontal misfit of an implant supported 3-unit fixed prosthodontics on the stress development at the marginal cortical bone surrounding implant neck. Two finite element models consisting of a three unit fixed prosthodontics and an implant/bone complex were constructed on a three dimensional basis. The three unit fixed prosthodontics were designed either shorter (d=17.8mm model) or longer (d=18.0mm model) by 0.1mm than the span of two implants placed at the mandibular second premolar and second molar areas 17.9mm apart. Fitting of the fixed prosthodontics onto the implant abutments was simulated by a total of 6 steps, that is to say, 0.1mm displacement per each step, using DEFORM 3D (ver 6.1, SFTC, Columbus, OH, USA) program. Stresses in the fixed prosthodontics and implants were evaluated using von-Mises stress, maximum compressive stress, and radial stress as necessary. The d=17.8mm model assembled successfully on to the implant abutments while d=18.0mm model did not. Regardless if the fixed prosthodontics fitted onto the abutments or not, excessively higher stresses developed during the course of assembly trial and thereafter. On the marginal cortical bone around implants during the assembly, the peak tensile and compressive stresses were as high as 186.9MPa and 114.1MPa, respectively, even after the final sitting of the fixed prosthodontics (for d=17.8mm model). For this case, the area of marginal bone subject to compressive stresses above 55MPa, equivalent of the $4,000{\mu}{\varepsilon}$, i.e. the reported threshold strain to inhibit physiological remodeling of human cortical bone, extended up to 2mm away from implant during the assembly. Horizontal misfit of 0.1mm can produce excessively high stresses on the marginal cortical bone not only during the fixed prosthodontics assembly but also thereafter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.11
• /
• pp.1318-1323
• /
• 2010

A lot of demand for parts of millimeter wave band, as would be expected 57~63 GHz band down conversion mixer was designed and fabricated using IHP 0.25 um SiGe process. Designed and fabricated mixer was double balanced type and located reduced 3D balun at RF port and buffer amplifier at outport for suppression LO signal and conversion gain. Fabricated mixer measured conversion gain of 13.8 dB, $P1dB_{in}$ -17 dBm and 88 mA of current consumption characteristics, respectively.

• Korean Journal of Ichthyology
• /
• v.12 no.3
• /
• pp.173-179
• /
• 2000

Effects of Estradiol-$17\beta(E_2)$ and 2, 4-dichlorophenoxy acetic acid (2, 4-D) on vitellogenin(VTG) production were investigated in primary hepatocyte culture of olive flounder, Paralichthys olivaceus. Highest survival rate of hepatocyte were observed at $27^{\circ}C$, which markedly declined equal to 50% of those of $15^{\circ}C$. Vitellogenin production peaked at the concentration of $10^{-6}M\;E_2$. No effect was observed on VTG production at various concentrations of 2, 4-D. However, a low concentration of 2, 4-D (ie, $10^{-8}M$) only appeared increased VTG production. $E_2$ or $10^{-8}M$ 2, 4-D-primed VTG production was markedly inhibited by the addition of $10^{-6}M$ tamoxifen to the culture medium(P<0.01). Inhibition was not affected by combinational treatment with $10^{-6}M$ $E_2$ and $10^{-6}M$ 2, 4-D. These results from the current investigation suggest that 2, 4-D mimics $E_2$, but the mechanism of reaction in inducing the $E_2$ receptor are different in VTG production in oliver flounder hepatocytes.

• Archives of Pharmacal Research
• /
• v.26 no.8
• /
• pp.620-630
• /
• 2003

The proliferative effects of thirty Oriental medicinal herbs on MCF-7 (estrogen-sensitive breast cancer cell line) and ROS 17/2.8 osteoblast-like cells were determined using the MTT assay. Methanol extracts from several herbs was found to show proliferative activity on the above two cell lines in the range of 5 to 100 $\mu$g/mL. Among these active herbs, the methanol extract from the rhizomes of Drynaria fortunei showed the most potent proliferative activity, and the cell proliferations were significantly increase by 136 and 158% in the MCF-7 and ROS 17/2.8 cells, respectively, when treated with 100 $\mu$ g/mL. Through a bioassay-guided separation, eight flavonoids, including four new flavan-3-ols and two propelargonidins, together with the known (-)-epiafzelechin and naringin, were isolated. Their chemical structures were characterized as (-)-epiafzelechin (1), (-)-epiafzelechin-3-O-$\beta$-D-allopyranoside (2), (-)-epiafzelechin-3-O-(6"-O-acetyl)-$\beta$-D-allopyranoside (3), 4$\beta$-carboxymethyl-(-)-epiafzelechin methyl ester (4), 4$\beta$-car-boxymethyl-(-)-epiafzelechin sodium salt (5), naringin (6), (-)-epiafzelechin-(4$\beta$\rightarrow8)-4$\beta$-car-boxymethylepiafzelechin methyl ester (7) and (-)-epiafzelechin-($4\beta\rightarrow8, 2\beta\rightarrowΟ\rightarrow7)-epiafzelechin-(4\beta\righarrow8)-epiafzelechin (8) by extensive 1D and 2D NMR spectroscopy. Most of these flavonoids, in the range of $10^{-15}∼10^{-6}$ M, accelerated the proliferation of MCF-7 cell, with compounds 7 and 8, in the range of $10^{-15}∼10^{-12}$ M, showing especially potent proliferation effects. Meanwhile, seven flavonoids, with the exception of compound 4, stimulated the proliferation of ROS 17/2.8 cells in the range of $10^{-15}∼10^{-6}$ M, with compounds 5-8 especially accelerating the proliferation, in dose-dependent manners ($10^{-15}∼10^{-9}$ M), and their proliferative effect was much stronger than that of $E_2$ and genistein. These results suggest that propelargonidin dimers and trimers isolated from the rhizomes of Drynaria fortunei may be useful as potential phytoestrogens, which play important physiological roles in the prevention of postmenopausal osteoporosis.

• Natural Product Sciences
• /
• v.21 no.3
• /
• pp.176-184
• /
• 2015

In our search for natural soluble epoxide hydrolase (sEH) inhibitors from plants, an extract of the dried whole plants of Euphorbia supina Rafin was found to significantly inhibit sEH activity in vitro. Phytochemical investigation of E. supina resulted in isolation of 17 compounds (1 - 17), including triterpenes (1 - 4), phenolic compounds (5 - 8), and flavonoid derivatives (9 - 17). The structures of the isolated compounds were established mainly by extensive analysis of the 1D and 2D NMR, and MS data. All of the isolated compounds were evaluated for their sEH inhibitory activity. Among the isolated phenolic compounds, 8 was identified as a significant inhibitor of sEH, with an IC₅₀ value of 15.4 ± 1.3 μM. Additionally, a kinetic analysis of isolated compounds (2, 5, 8 - 11, 13, and 17) indicated that the inhibitory effects of flavonoid derivatives 10 and 11 were of mixed-type, with inhibitory constants (K_i) ranging from 3.6 ± 0.8 to 21.8 ± 1.0 μM, whereas compounds 2, 5, 8, 9, 13, and 17 were non-competitive inhibitors with inhibition K_i values ranging from 3.3 ± 0.2 to 39.5 ± 0.0 μM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.7 s.110
• /
• pp.665-672
• /
• 2006

In this paper, we propose and fabricate the dual-band microstrip patch antenna with parasitic patch for S-DMB(Satellite-Digital Multimedia Broadcasting) and ITS (Intelligent Transport System) services. The measured - 10 dB bandwidth and the minimum return loss is 300 MHz and - 27 dB for S-DMB, 600 MHz and -17 dB for ITS, respectively. It is noticed that the measured and simulated results are agreed well. The S-DMB antenna has conical beam pattern in the vertical plane and has omni-directional beam pattern in the horizontal plane. The conical beam pattern has the maximum gain about 4.2 dBi when ${\theta}$ is $45^{\circ}$ at the center frequency of 2.6 GHz. The ITS antenna has directional beam pattern in the vertical plane that has maximum gain about 6.4 dBi when ${\theta}$ is $0^{\circ}$ at the center frequency of 5.8 GHz.

• Journal of IKEEE
• /
• v.17 no.3
• /
• pp.275-283
• /
• 2013

In this paper, a 8bit 10Ms/s CMOS Folding and Interpolation analog-to-digital convertor is proposed. The architecture of the proposed ADC is based on a Folding & Interpolation using FR(Folding Rate)=8, NFB(Number of Folding Block)=4, IR(Interpolation Rate)=8. The proposed ADC adopts a preamplifier sharing method to decrease the number of preamplifier by half comparing to the conventional ones. This chip has been fabricated with a 0.35[um] CMOS technology. The effective chip area is $1.8[mm]{\times}2.11[mm]$ and it consumes 20[mA] at 3.3 power supply with 10[MHz] clock. The INL is -0.57, +0.61 [LSB] and DNL is -0.4, +0.51 [LSB]. The SFDR is 48.9[dB] and SNDR is 47.9[dB](ENOB 7.6b) when the input frequency is 100[kHz] at 10[MHz] conversion rate.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.5
• /
• pp.815-820
• /
• 2008

Recently the frequency assignment and the technical specifications of UWB systems for communications are completed. Therefore many UWB systems have been developed. In our country $3.1{\sim}4.8GHz$ and $7.2{\sim}10.2GHz$ are assigned for UWB systems for communications. When we consider RF technologies and the easy implementation of UWB systems, UWB systems used in the low band are more developed than high band systems. In this paper we design and implement a BPF for low band UWB systems by means of considering the easy implementation of UWB systems. The designed and implemented BPFs are low band filter and low band channel filters. The measured results of the low band filter show that the filter has 21.85dB and 17.91dB attenuation at 3.1GHz and 4.8GHz, 1.53GHz of -10dB bandwidth and 2dB of insertion loss. Low band can be divided into 3 channels with 500MHz of the channel bandwidth. The channel filter for channel number 1 has the characteristics of 24.85dB attenuation at 3.1GHz, 0.61GHz of -10dB bandwidth and 1.87dB of insertion loss. The filter for channel 3 in low band has 19.2dB of attenuation at 4.8GHz, 0.49GHz of -10dB bandwidth and 2.49dB of insertion loss.

• Review of Korea Contents Association
• /
• v.8 no.1
• /
• pp.12-17
• /
• 2010

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.4
• /
• pp.519-526
• /
• 2002

In this paper, a microstrip patch array antenna for a Doppler radar at 10.525GHz is desinged and fabricated. To be used for mobile radar system, the antenna is fabricated on a single layer laminate to resist a fire impact and is covered with the Teflon foam. To obtain the desired characteristics, the array antenna is designed 4$\times$8 array using a corporate 3-dB amplitude taper. Also, using square patch elements, the antenna can be converted to a circular polarized antenna later. The designed and fabricated array antenna has the reflection coefficient$({S_11})$ -53.498dB, the horizontal beam width of $10^{\circ}$, the vertical beam width of $18.8^{\circ}$, the gain of 21dBi, the bandwidth of 220MHz for VSWR<1.5 and a side lobe level of less than -17.5dB.