• Investigative Magnetic Resonance Imaging
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• v.8 no.1
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• pp.1-8
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• 2004

Purpose : Information about electrical activity inside the brain during fMRl scans is very useful in monitoring physiological function of the patient or locating the spatial position of the activated region in the brain. However, many additional noises appear in the EEG signal acquired during the MRI scan. Gradient induced noise is the biggest one among the noises. In this work, we propose a gradient noise reduction method using the independent component analysis (ICA) method. Materials and Methods : We used a 29-channel MR-compatible EEG measurement system and a 3.0 Tesla MRI system. We measured EEG signals on a subject lying inside the magnet during EPI scans. We selectively removed the gradient noise from the measured EEG signal using the ICA method. We compared the results with the ones obtained with conventional averaging method and PCA method. Results : All the noise reduction methods including the averaging and PCA methods were effective in removing the noise in some extent. However, the proposed ICA method was found to be superior to the other methods. Conclusion : Gradient noise in EEG signals acquired during fMRI scans can be effectively reduced by the ICA method. The noise-reduced EEG signal can be used in fMRI studies of epileptic patients or combinatory studies of fMRI and EEG.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.288-295
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• 1999

Nineteen japonica and Tongil-type rices were selected from seventy nine Korean and Japanese rice cultivars grown in 1989 based on the water uptake behavior of milled rice under the room temperature and boiling conditions. The selected rice cultivars were investigated for water absorbability and some physicochemical characteristics of milled rice, proper water amount for cooking and sensory evaluation of cooked rice. The relationships among the tested grain properties were also examined. The highest varietal variation of water uptake rate was observed at twenty minutes after soaking in water. The maximum water uptake of milled rices at room temperature occurred mostly at about eighty minutes after soaking in water. Newly harvested rices showed a significantly lower water uptake rate of milled rice at 20 minutes after soaking, a relatively higher maximum water absorption ratio under the room temperature, and the less water uptake and volume expansion of boiled rice compared with the one-year old rice samples. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice ansd the palatability of cooked rice. The water/rice ratio(in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was averaged to 2.63(in v/v basis). The water amount needed for optimum cooking was the lowest in Cheongcheongbyeo (Tongil-type rice) and the highest in Jinbubyeo, and the amount could be estimated with about 70% fittness by the multiple regression formula based on some water uptake characteristics, ADV and amylose content of milled rice as the independent variables. Nineteen rice cultivars were classified into seven groups based on scatter diagram projected by principal component analysis using eight properties related to water uptake and gelatinization of milled rice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2038-2045
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• 2010

Households' monthly average income is composed of various factors. This study paper studies focuses on estimating the determinants of a households' monthly average income. The region for analysis consist of three groups, that is, the whole country, a metropolitan city(such as Busan, Daegu, Incheon, Gwangiu, Daejeon, Ulsan.) and Seoul. Analyzing period be formed over a 57 time points(2005. 01~2009. 09). In this paper the dependent variable setting up the households' monthly average income, explanatory (independent) variables are composed of the consumer price index, employment to population ratio, Index of housing sale price, the preceding composite index, loans of housing mortgage, spending rate for care medical expense and the composite stock price index. In looking at the factors which determine the monthly average income, evidence was produced supporting the hypothesis that there is a significant positive relationship between the composite index and housing loans. The study also produced evidence supporting the view that there is a significant negative relationship between employment ratios, the house sale pricing index and spending rates for care or medical needs. The study found that the consumer price index and composite stock price index were not significant variables. The implications of these findings are discussed for further research.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.73-85
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• 2006

Array observations of the vertical component of microtremors are frequently conducted to estimate a subsurface layered-earth structure on the assumption that microtremors consist predominantly of the fundamental mode Rayleigh waves. As a useful tool in the data collection, processing and analysis, the spatial autocorrelation (SPAC) method is widely used, which in practice requires a circle array consisting of M circumferential stations and one centre station (called "M-station circle array", where M is the number of stations). The present paper considers the minimum number of stations required for a circle array for efficient data collection in terms of analytical efficacy and field effort. This study first rearranges the theoretical background of the SPAC algorithm, in which the SPAC coefficient for a circle array with M infinite is solely expressed as the Bessel function, $J_0(rk)$ (r is the radius and k the wavenumber). Secondly, the SPAC coefficient including error terms independent of the microtremor energy field for an M-station circle array is analytically derived within a constraint for the wave direction across the array, and is numerically evaluated in respect of these error terms. The main results of the evaluation are: 1) that the 3-station circle array when compared with other 4-, 5-, and 9-station arrays is the most efficient and favourable for observation of microtremors if the SPAC coefficients are used up to a frequency at which the coefficient takes the first minimum value, and 2) that the Nyquist wavenumber is the most influential factor that determines the upper limit of the frequency range up to which the valid SPAC coefficient can be estimated.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.205-214
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• 2006

Background : Acute exacerbations form a major component of the socioeconomic burden of COPD. As yet, little information is available about the long-term outcome of patients who have been hospitalized with acute exacerbations, although high mortality rates have been reported. The aim of this study was to determine predictors of long-term mortality after hospitalization for acute exacerbation of COPD. Methods : We performed a retrospective cohort study of consecutive patients admitted to the hospital for COPD exacerbation between 2000 through 2004. Patients who had died in hospital or within 6-months after discharge, had tuberculosis scar, pleural thickening or bronchiectasis by chest radiography or had been diagnosed with malignancy during follow-up periods were excluded. Results : Mean age of patients was 69.5 years, mean follow-up duration was 49 months, and mean $FEV_1$ was 1.00L (46% of predicted). Mortality was 35% (17/48). In the multivariate Cox regression analysis, heart rate of 100/min or more (p=0.003; relative risk [RR], 11.99; 95% confidence interval [CI], 2.34-61.44) and right ventricular systolic pressure (RVSP) of 35mmHg or more (p=0.019; RR, 6.85; 95% CI, 1.38-34.02) were independent predictors of mortality. Conclusion : Heart rate and RVSP in stable state may be useful in predicting long-term mortality for COPD patients admitted to hospital with acute exacerbation.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3811-3816
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• 2015

Background: Hairy and enhancer of split 1 (Hes-1) protein is a downstream target of Notch signaling and is a basic helix-loop-helix transcriptional repressor. However, definitive evidence for a role in hepatocellular carcinoma (HCC) cells has not been reported. Here, Hes-1 was revealed to an important component of the Notch signaling cascade in HCC cell lines possessing different potential for lung metastasis. Materials and Methods: RNAi mediated by plasmid constructs was used to analyze the role of Hes-1 in MHCC-97L HCC cells by assessing proliferation, apoptosis, cell migration and matrigel invasion following transfection. Hes-1 protein expression analysis in HCC tissue was also conducted by immunohistochemistry. Results: Our studies revealed that Hes-1 was decreased in HCC cell lines with higher lung metastasis potential at both the mRNA and protein levels. Down-regulation of the Hes-1 gene in MHCC-97L cells resulted in increased cell proliferation, reduced apoptosis and increased migration and invasion. Conclusions: Hes-1 has potential prognostic value in post-surgical HCC patients and may be an independent prognostic indicator for overall survival and tumor recurrence. These findings have important implications for understanding the mechanisms by which Hes-1 participates in tumor proliferation and invasion.

• Progress in Superconductivity
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• v.7 no.1
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• pp.28-35
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• 2005

We propose a method to measure atrial arrhythmias (AA) such as atrial fibrillation (Afb) and atrial flutter (Afl) with a SQUID magnetocardiograph (MCG) system. To detect AA is one of challenging topics in MCG. As the AA generally have irregular rhythm and atrio-ventricular conduction, the MCG signal cannot be improved by QRS averaging; therefore a SQUID MCG system having a high SNR is required to measure informative atrial excitation with a single scan. In the case of Afb, diminished f waves are much smaller than normal P waves because the sources are usually located on the posterior wall of the heart. In this study, we utilize an MCG system measuring tangential field components, which is known to be more sensitive to a deeper current source. The average noise spectral density of the whole system in a magnetic shielded room was $10\;fT/{\surd}Hz(a)\;1\;Hz\;and\;5\;fT/{\surd}Hz\;(a)\;100\;Hz$. We measured the MCG signals of patients with chronic Afb and Afl. Before the AA measurement, the comparison between the measurements in supine and prone positions for P waves has been conducted and the experiment gave a result that the supine position is more suitable to measure the atrial excitation. Therefore, the AA was measured in subject's supine position. Clinical potential of AA measurement in MCG is to find an aspect of a reentry circuit and to localize the abnormal stimulation noninvasively. To give useful information about the abnormal excitation, we have developed a method, separative synthetic aperture magnetometry (sSAM). The basic idea of sSAM is to visualize current source distribution corresponding to the atrial excitation, which are separated from the ventricular excitation and the Gaussian sensor noises. By using sSAM, we localized the source of an Afl successfully.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.202-208
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• 2012

Fetal heart rate monitoring is important information to assess fetal well-being. Non-invasive fetal ECG (electrocardiography) can be derived from maternal abdominal signal. And various promising signal processing methods have been introduced to extract fetal ECG from mother's composite abdominal signal. However, non-invasive fetal ECG monitoring still has not been widely used in clinical practice due to insufficient reliable measurement and difficulty of signal processing. In application of signal processing method to extract fetal ECG, it might be lower signal to noise ratio due to time varying white Gaussian noise. In this paper, time varying Kalman smoother is proposed to remove white noise in fetal ECG and its feasibility is confirmed. Wiener process was set as Kalman system model and covariance matrix was modified according to white Gaussian noise level. Modified error covariance matrix changed Kalman gain and degree of smoothness. Optimal covariance matrix according to various amplitude in Gaussian white noise was extracted by 5 channel fetal ECG model, and feasibility of proposed method could be confirmed.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5237-5242
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• 2013

Background: Inflammation is a critical component of tumor progression. Many cancers arise from sites of infection, chronic irritation, and inflammation. It is now becoming clear that the tumour microenvironment, which is largely orchestrated by inflammatory cells, is an essential participant in the neoplastic process, promoting proliferation, survival and migration. Platelets can release some growth factors such as platelet-derived growth factor, platelet factor 4, and thrombospondin. Such factors have been shown to promote hematogenous tumour spread, tumor cell adhesion and invasion, and angiogenesis and to play an important role in tumor progression. In this study, we aimed to investigate effects of the pretreatment neutrophil to lymphocyte ratio (NLR) and the platelet to lymphocyte ratio (PLR) on survival and response to chemoradiotherapy in patients with non-small-cell lung cancer (NSCLC). Materials and Methods: Ninety-four patients with non-metastatic NSCLC were included and separated into two groups according to median valuse of NLR and PLR (low:<3.44 or high:${\geq}3.44$ and low:<194 or high${\geq}194$, respectively). Results: Pretreatment high NLR and PLR were associated with significantly shorter disease-free and overall survival rates. Multivariate analysis revealed that the overall survival rates were significantly linked with PLR (OR: 1.87, CI: 1.20-2.91, p: 0.006) and response to chemoradiotherapy (OR: 1.80, CI: 1.14-2.81, p: 0.012) and the disease-free survival rates were significantly associated with NLR (OR: 1.81, CI: 1.16-2.82, p: 0.009) and response to chemoradiotherapy (OR: 2.30, CI: 1.45-3.66, p: 0.001). There was no significant difference between patients with high and low NLR in terms of response to chemoradiotherapy. Similarly, there was no significant influence of the PLR. Conclusions: Pretreatment NLR and PLR measurements can provide important prognostic results in patients with NSCLC and assessment of the two parameters together appears to better predict the prognosis in patients with NSCLC. The effect of inflammation, indicators of NLR and PLR, on survival seems independent of the response to chemoradiotherapy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.272-277
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• 2010

In respect complication of group, rate of arrearage in domestic bank is composed of various factors. This paper studies focus on estimating the determinants of the rate of arrearage in domestic bank using panel data model. The volume of analysis consist of 3 groups(loaned patterns of enterprise, housekeeping, credit card). Analyzing period be formed over a 54 point(2005. 1~ 2009. 06). In this paper dependent variable setting up rate of arrearage in domestic bank, explanatory(independent) variables composed of the consumer price index, composite stock price index, rate of exchange, the coincident composite index, national housing bonds and employment rate. The result of estimating the rate of arrearage in domestic bank provides empirical evidences of significance positive relationships between the consumer price index However this study provides empirical evidences of significance negative relationships between the coincident composite index and the composite stock price index. The explanatory variables, that is, rate of exchange, national housing bonds and the employment rate are non-significance variables of negative factor. Implication of these findings are discussed for content research and practices.