• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.889-896
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• 2015

Matrix metalloproteinase-2 (MMP2) is an endopeptidase, mainly responsible for degradation of extracellular matrix components, which plays an important role in cancer disease. A single nucleotide polymorphism (SNP) at -1306 disrupts a Sp1-type promoter site. The results from the published studies on the association between MMP2 -1306 C>T polymorphism and cancer risk are contradictory and inconclusive. In the present study, a meta-analysis was therefore performed to evaluate the strength of any association between the MMP2 -1306 C>T polymorphism and risk of cancer. We searched all eligible studies published on association between MMP2 -1306 C>T polymorphism and cancer risk in PubMed (Medline), EMBASE and Google Scholar online web databases until December 2013. Genotype distribution data were collected to calculate the pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) to examine the strength of the association. A total of 8,590 cancer cases and 9,601 controls were included from twenty nine eligible case control studies. Overall pooled analysis suggested significantly reduced risk associated with heterozygous genotype (CT vs CC: OR=0.758, 95%CI=0.637 to 0.902, p=0.002) and dominant model (TT+CT vs CC: OR=0.816, 95%CI=0.678 to 0.982, p=0.032) genetic models. However, allelic (T vs C: OR=0.882, 95%CI=0.738 to 1.055, p=0.169), homozygous (TT vs CC: OR=1.185, 95%CI=0.825 to 1.700, p=0.358) and recessive (TT vs CC+CT: OR=1.268, 95%CI=0.897 to 1.793, p=0.179) models did not show any risk. No evidence of publication bias was detected during the analysis. The results of present meta-analysis suggest that the MMP2 -1306 C>T polymorphism is significantly associated with reduced risk of cancer. However, further studies with consideration of different populations will be required to evaluate this relationship in more detail.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.323-328
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• 2004

The development of group-specific tissue probability maps (TPM) provides a priori knowledge for better result of cerebral tissue classification with regard to the inter-ethnic differences of inter-subject variability. We present sequential procedures of group-specific TPM and evaluate the age effects in the structural differences of TPM. We investigated 100 healthy volunteers with high resolution MRI scalming. The subjects were classified into young (60, 25.92+4.58) and old groups (40, 58.83${\pm}$8.10) according to the age. To avoid any bias from random selected single subject and improve registration robustness, average atlas as target for TPM was constructed from skull-stripped whole data using linear and nonlinear registration of AIR. Each subject was segmented into binary images of gray matter, white matter, and cerebrospinal fluid using fuzzy clustering and normalized into the space of average atlas. The probability images were the means of these binary images, and contained values in the range of zero to one. A TPM of a given tissue is a spatial probability distribution representing a certain subject population. In the spatial distribution of tissue probability according to the threshold of probability, the old group exhibited enlarged ventricles and overall GM atrophy as age-specific changes, compared to the young group. Our results are generally consistent with the few published studies on age differences in the brain morphology. The more similar the morphology of the subject is to the average of the population represented by the TPM, the better the entire classification procedure should work. Therefore, we suggest that group-specific TPM should be used as a priori information for the cerebral tissue classification.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.13-20
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• 2005

Fiber-Bragg-grating external cavity laser(FGL) modules were fabricated and experimentally analyzed. Proposed as a cost-effective solution for optical sources in the WDM-PON access network, FGL modules were packaged to TO-CAN type. We obtained a low threshold current of 13 mA, and an optical output power of 3.6 mW with a bias current of 60 mA at $25^{\circ}C$. The lasing wavelength dependencies on current and temperature were as small as 5.2 pm/mA and 30 pm/$^{\circ}C$, respectively. These change rates of the wavelength with the temperature and current are smaller than those of the DFB laser. Single-mode oscillations with the side-mode suppression ratio(SMSR) over 30 dB are maintained above the threshold current level. The FGL modules can be directly modulated at 155 Mbps, PRBS(2$^{23}$ -1) NRZ signal. Through the BER plots, we did not see the significant degradations before and after the transmission over 20km of the SMF at 155 Mb/s.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.217-223
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• 2010

We grew multi-stacked InAs/$In_{0.1}Ga_{0.9}As$ DWELL (dot-in-a-well) structure by metal organic chemical vapor deposition and investigated optical properties by photoluminescence and I-V characteristics by dark current measurement. When stacking InAs quantum dots (QDs) with same growth parameter, the size and density of QDs were changed, resulting in the bimodal emission peak. By decreasing the flow rate of TMIn, we achieved the uniform multi-stacked QD structure which had the single emission peak and high PL intensity. As the growth temperature of n-type GaAs top contact layer (TCL) is above $600^{\circ}C$, the PL intensity severely decreased and dark current level increased. At bias of 0.5 V, the activation energy for temperature dependence of dark current decreased from 106 meV to 48 meV with increasing the growth temperature of n-type GaAs TCL from 580 to $650^{\circ}C$. This suggest that the thermal escape of bounded electrons and non-radiative transition become dominant due to the thermal inter-diffusion at the interface between InAs QDs and $In_{0.1}Ga_{0.9}As$ well layer.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.232-245
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• 2017

In this study, the high-resolution numerical simulation results considering landuse characteristics are analyzed by using single layer Urban Canopy Model (UCM) in Weather Research Forecast (WRF). For this, the impact of urban parameters such as roughness length and anthropogenic heat in UCM is analyzed. These values are adjusted to Seoul metropolitan area in Korea. The results of assessment are verified against observation from surface and flux tower. Forecast system equipped with UCM shows an overall improvement in the simulations of meteorological parameters, especially temperature at 2 m, surface sensible and latent heat flux. Major contribution of UCM is appreciably found in urban area rather than non-urban. The non-urban area is indirectly affected. In simulated latent heat flux, applying UCM is possible to simulate the change similarly with observations on urban area. Anthropogenic heat employed in UCM shows the most realistic results in terms of temperature and surface heat flux, indicating thermodynamic treatment of UCM could enhance the skills of high resolution forecast model in urban and non-urban area.

• Mycobiology
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• v.45 no.4
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• pp.379-384
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• 2017

In mating of Lentinula edodes, dikaryotic strains generated from certain monokaryotic strains such as the B2 used in this study tend to show better quality of fruiting bodies regardless of the mated monokaryotic strains. Unlike B2, dikaryotic strains generated from B16 generally show low yields, with deformed or underdeveloped fruiting bodies. This indicates that the two nuclei in the cytoplasm do not contribute equally to the physiology of dikaryotic L. edodes, suggesting an expression bias in the allelic genes of the two nuclei. To understand the role of each nucleus in dikaryotic strains, we investigated single nucleotide polymorphisms (SNPs) in laccase genes of monokaryotic strains to reveal nuclear origin of the expressed mRNAs in dikaryotic strain. We performed reverse transcription PCR (RT-PCR) analysis using total RNAs extracted from dikaryotic strains (A5B2, A18B2, and A2B16) as well as from compatible monokaryotic strains (A5, A18, and B2 for A5B2 and A18B2; A2 and B16 for A2B16). RT-PCR results revealed that Lcc1, Lcc2, Lcc4, Lcc7, and Lcc10 were the mainly expressed laccase genes in the L. edodes genome. To determine the nuclear origin of these laccase genes, the genomic DNA sequences in monokaryotic strains were analyzed, thereby revealing five SNPs in Lcc4 and two in Lcc7. Subsequent sequence analysis of laccase mRNAs expressed in dikaryotic strains revealed that these were almost exclusively expressed from B2-originated nuclei in A5B2 and A18B2 whereas B16 nucleus did not contribute to laccase expression in A2B16 strain. This suggests that B2 nucleus dominates the expression of allelic genes, thereby governing the physiology of dikaryons.

• Journal of Korea Water Resources Association
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• v.50 no.3
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• pp.155-167
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• 2017

Accurate QPE (Quantitative Precipitation Estimation) and the quality of the rainfall data for hydrological analysis are very important factors. Especially, the quality has a great influence on flood runoff result. It needs to know characteristics of the uncertainties in radar QPE for the reliable flood analysis. The purpose of this study is to present a probabilistic approach which defines the range of possible values or probabilistic distributions rather than a single value to consider the uncertainties in radar QPE and evaluate its applicability by applying it to radar rainfall. This study generated radar rainfall ensemble for the storms by the typhoon 'Sanba' on Namgang dam basin, Korea. It was shown that the rainfall ensemble is able to simulate well the pattern of the rain-gauge rainfall as well as to correct well the overall bias of the radar rainfall. The suggested ensemble technique represented well the uncertainties of radar QPE. As a result, the rainfall ensemble model by a probabilistic approach can provide various rainfall scenarios which is a useful information for a decision making such as flood forecasting and warning.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1235-1242
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• 2008

In this paper, x-ray image sensor of photon counting type having a $32{\times}32$ pixel array is designed with $0.18{\mu}m$ triple-well CMOS process. Each pixel of the designed image sensor has an area of loot $100{\times}100\;{\mu}m2$ and is composed of about 400 transistors. It has an open pad of an area of $50{\times}50{\mu}m2$ of CSA(charge Sensitive Amplifier) with x-ray detector through a bump bonding. To reduce layout size, self-biased folded cascode CMOS OP amp is used instead of folded cascode OP amp with voltage bias circuit at each single-pixel CSA, and 15-bit LFSR(Linear Feedback Shift Register) counter clock generator is proposed to remove short pulse which occurs from the clock before and after it enters the counting mode. And it is designed that sensor data can be read out of the sensor column by column using a column address decoder to reduce the maximum current of the CMOS x-ray image sensor in the readout mode.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1545-1553
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• 2018

Recent eruptive activity at Kīlauea Volcano started on at the end of April in 2018 showed rapid ground deflation between May and June in 2018. On summit area Halema'uma'u lava lake continued to drop at high speed and Kīlauea's summit continued to deflate. GPS receivers and electronic tiltmeters detected the surface deformation greater than 2 meters. We explored the time-series surface deformation at Kīlauea Volcano, focusing on the early stage of eruptive activity, using multi-temporal COSMO-SkyMed SAR imagery. The observed maximum deformation in line-of-sight (LOS) direction was about -1.5 meter, and it indicates approximately -1.9 meter in subsiding direction by applying incidence angle. The results showed that summit began to deflate just after the event started and most of deformation occurred between early May and the end of June. Moreover, we confirmed that summit's deflation rarely happened since July 2018, which means volcanic activity entered a stable stage. The best-fit magma source model based on time-series surface deformation demonstrated that magma chambers were lying at depths between 2-3 km, and it showed a deepening trend in time. Along with the change of source depth, the center of each magma model moved toward the southwest according to the time. These results have a potential risk of including bias coming from single track observation. Therefore, to complement the initial results, we need to generate precise magma source model based on three-dimensional measurements in further research.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.309-316
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• 2019

In this paper, a low-jitter delay-locked loop that compensates for local clock skew is presented. The proposed DLL consists of a phase splitter, a phase detector(PD), a charge pump, a bias generator, a voltage-controlled delay line(VCDL), and a level converter. The VCDL uses self-biased delay cells using current mode logic(CML) to have insensitive characteristics to temperature and supply noises. The phase splitter generates two reference clocks which are used as the differential inputs of the VCDL. The PD uses the only single clock from the phase splitter because the PD in the proposed circuit uses CMOS logic that consumes less power compared to CML. Therefore, the output of the VCDL is also converted to the rail-to-rail signal by the level converter for the PD as well as the local clock distribution circuit. The proposed circuit has been designed with a $0.13-{\mu}m$ CMOS process. A global CLK with a frequency of 1-GHz is externally applied to the circuit. As a result, after about 19 cycles, the proposed DLL is locked at a point that the control voltage is 597.83mV with the jitter of 1.05ps.