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A Study on the Availability of the On-Board Imager(OBI) and Cone-Beam CT(CBCT) in the Verification of Patient Set-up (온보드 영상장치(On-Board Imager) 및 콘빔CT(CBCT)를 이용한 환자 자세 검증의 유용성에 대한 연구)

  • Bak, Jino;Park, Sung-Ho;Park, Suk-Won
    • Radiation Oncology Journal
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    • v.26 no.2
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    • pp.118-125
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    • 2008
  • Purpose: On-line image guided radiation therapy(on-line IGRT) and(kV X-ray images or cone beam CT images) were obtained by an on-board imager(OBI) and cone beam CT(CBCT), respectively. The images were then compared with simulated images to evaluate the patient's setup and correct for deviations. The setup deviations between the simulated images(kV or CBCT images), were computed from 2D/2D match or 3D/3D match programs, respectively. We then investigated the correctness of the calculated deviations. Materials and Methods: After the simulation and treatment planning for the RANDO phantom, the phantom was positioned on the treatment table. The phantom setup process was performed with side wall lasers which standardized treatment setup of the phantom with the simulated images, after the establishment of tolerance limits for laser line thickness. After a known translation or rotation angle was applied to the phantom, the kV X-ray images and CBCT images were obtained. Next, 2D/2D match and 3D/3D match with simulation CT images were taken. Lastly, the results were analyzed for accuracy of positional correction. Results: In the case of the 2D/2D match using kV X-ray and simulation images, a setup correction within $0.06^{\circ}$ for rotation only, 1.8 mm for translation only, and 2.1 mm and $0.3^{\circ}$ for both rotation and translation, respectively, was possible. As for the 3D/3D match using CBCT images, a correction within $0.03^{\circ}$ for rotation only, 0.16 mm for translation only, and 1.5 mm for translation and $0.0^{\circ}$ for rotation, respectively, was possible. Conclusion: The use of OBI or CBCT for the on-line IGRT provides the ability to exactly reproduce the simulated images in the setup of a patient in the treatment room. The fast detection and correction of a patient's positional error is possible in two dimensions via kV X-ray images from OBI and in three dimensions via CBCT with a higher accuracy. Consequently, the on-line IGRT represents a promising and reliable treatment procedure.

Myocardial Tracer Uptake in SPECT Images after Direct Intracoronary Injection Of TI-201: Comparison with Stress-Reinjection Images (관동맥내 주사 TI-201 SPECT에서 심근 분절의 섭취: 부하-재주사 TI-201 영상과의 비교)

  • Seo, Ji-Hyoung;Kang, Seong-Min;Bae, Jin-Ho;Lee, Yong-Jin;Lee, Sang-Woo;Yoo, Jeong-Soo;Ahn, Byeong-Cheol;Cho, Yong-Geun;Lee, Jae-Tae
    • Nuclear Medicine and Molecular Imaging
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    • v.41 no.4
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    • pp.291-298
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    • 2007
  • Purpose: To investigate the feasibility of TI-201 SPECT with intra coronary injection (lC-I) in the detection of viable myocardium, we have performed SPECT imaging after direct intracoronary injection of TI-201 and images were compared with those of stress-reinjection (Re-I) SPECT. Methods: Fourteen coronary artery disease patients (male 11, mean age 54 years) who had myocardial infarction or demonstrated left ventricular wall motion abnormality on echocardiography were enrolled. Three mCi of TI-201 was injected into both coronary arteries during angiography and images were acquired between 6- and 24-hour after injection. Reinjection imaging with 1 mCi of TI-201 was performed at 4-hour after adenosine stress imaging with 3 mCi of TI-201. Images were interpreted according to 4-grade visual scoring system (grade 0-3). Segments with mild to moderated uptake (${\leq}$grade 1), and upgraded more than one score with reinjection, and were defined as viable myocardium. Results: Image quality was poor in two cases with IC-I. Numbers of non-viable segments were 60 (23.8%) with IC-I, and 38 (15.1%) with Re-I, respectively. Overall agreement for perfusion grade per myocardial segment in each IC-I and Re-I was 76.5%. Overall agreement for viable segment between IC-I and Re-I was 90.5%. Only one out of 38 segments interpreted as non-viable with Re-I were interpretated as viable with IC-I. And 23 out of 214 segments interpreted as viable with Re-I were interpreted as non-viable with IC-I. Conclusion: Intracoronary TI-201 SPECT seemed to be not advantageous over stress-rest reinjection imaging in the assessment of myocardial viability, mainly due to low count statistics at 6-hour or 24-hour delayed time points. The feasibility of intracoronary TI- 201 SPECT is considered to be limited.

Clinical Features and the Natural History of Dietary Protein Induced Proctocolitis: a Study on the Elimination of Offending Foods from the Maternal Diet (식품 단백질 유발성 직결장염의 임상 소견과 식이 조절에 관한 연구)

  • Choi, Seon Yun;Park, Moon Ho;Choi, Won Joung;Kang, Una;Oh, Hoon Kyu;Kam, Sin;Hwang, Jin-Bok
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.8 no.1
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    • pp.21-30
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    • 2005
  • Purpose: The aim of this study was to identify the clinical features and natural history of dietary protein induced proctocolitis (DPIPC) and to detect the causative foods of DPIPC, and to evaluate the effect of elimination of the foods on the course of the disease. Methods: Between March 2003 and July 2004, data from 30 consecutive patients with DPIPC who were followed for over 6 months, was reviewed. The diagnostic criterion used for DPIPC was an increase in the number of eosinophils in the lamina propria (${\geq}60per$ 10 high-power fields). In breast feeding mothers, 5 highly allergenic foods were eliminated from the maternal diet for 7 days, namely, allergenic food groups such as dairy products, eggs, nuts and soybean, fish and shellfish, and wheat and buckwheat. We observed the disappearance or appearance of hematochezia after elimination or challenge with the offending foods. Results: Before diagnosis infants were breast-fed (93.3%) or formula-fed (6.7%). Mean age at symptom onset was $11.5{\pm}5.1$ (5~24) weeks, and mean age at diagnosis was $17.8{\pm}9.5$ (8~56) weeks. Duration from symptom onset to diagnosis was $6.3{\pm}6.7$ (0~36) weeks. Mean peripheral blood eosinophil count was $478{\pm}320$ (40~1,790)/$mm^3$ and eosinophilia (> $250/mm^3$) was observedin 90.0% of patients. None of patients were found to have an increased serum IgE level. Of 15 patients that received sigmoidoscopy, nodular hyperplasia with erosion was observed in 93.3%. Of 27 patients whose mother ate the diet eliminated the 5 food groups, hematochezia diappeared in 74.1% of patients. Offending foods were identified as dairy products (37.5%), wheat and buckwheat (27.5%), fish and shellfish (20.0%), nuts and soybean (7.5%) and eggs (7.5%). A free maternal diet without patient's clinical symptoms was achieved at $29.4{\pm}8.7$ (9~44) weeks of patient's age, and a free baby diet without blood in stools was achieved at $37.5{\pm}9.7$ (12~56) weeks of age. Conclusion: DPIPC commonly occurs in exclusively breast-fed babies. Elimination of the above-mentioned 5 hyper-allergenic food groups from the maternal diet for 7days enables the detection of the offending foods. DPIPC is a transient disorder and 96.0% of patients can tolerate the offending foods at 12 months of age.

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Clinical Manifestations of the Lung Involvement in Behçet's Syndrome (Behçet 증후군에서 폐침범의 임상양상에 관한 고찰)

  • Park, Kwang Joo;Park, Seung Ho;Kim, Sang Jin;Kim, Hyung Jung;Chang, Joon;Ahn, Chul Min;Kim, Sung Kyu;Lee, Won Young
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.5
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    • pp.763-773
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    • 1996
  • Background : Behçet's syndrome is a chronic multisystemic disease affecting many organs such as skin, mucosa, eye, joint, central nervous system and blood vessels. Lung involvement occurs in 5% of Behçet's syndrome and is thought to be due to the pulmonary vasculitis leading to thromboembolism, aneurysm and arteriobronchial fistula. Pulmonary vasculitis in Behçet's syndrome is a unique clinical feature, differing from other vasculitis affecting the lung and is one of the major causes of death. Therefore, we examined the incidence, the clinical features, the radioloic findings and the clinical courses of the lung involvement in Behçet's syndrome. Methods: We retrospectively reviewed the medical records and radiologic studies of 10 cases of the lung involvement in Behçet's syndrome diagnosed at Yongdong Severance Hospital and Severance Hospital from 1986 to 1995. We analysed the clinical features, the radiological findings, the treatment modalities and the clinical courses. Results: 1) The incidence of the lung involvement in Behçet's syndrome was 2%(10/487). The male to female ratio was 8 : 2 and the mean age was 34 years. The presenting symptom was hemoptysis in 5 of 10 cases, and massive hemoptysis was noted in 2 cases. Other pulmonary symptoms were cough(6/10), dyspnea(4/10), and chest pain(2/10). Other manifestations were oral ulcers(10/10), genital ulcers(9/10), skin lesions(7/10), and eye lesions(6/10). 2) The laboratory findings were nonspecific. The posteroanterior views of chest radiographies showed multiple infiltrates(6/10), nodular or mass-like opacities(4/10), or normal findings(2/10). The chest CT scans showed multifocal consolidations(6/8), and aneurysms of the pulmonary aneries(4/8). The pulmonary angiographies were performed in 3 cases, and showed pulmonary artery aneurysms in 2 cases. The ventilation-perfusion scans in 2 cases of normal chest x-ray showed multiple mismatched findings. 3) The patients were treated with combination therapy consisting of corticosteroids, cyclophosphamide, and colchicine or anticoagulant agents. Surgical resection was performed in one case with a huge aneurysm. 4) We have followed up nine of ten cases. Three cases are well-being with medical therapy, two cases are severely disabled now and four cases died due to massive hemoptysis, massive pulmonary embolism, or sepsis. Conclusion : Pulmonary vasculitis is a main feature of the lung involvement of Behçet's syndrome, causing hemorrhage, aneurysmal formation, and/or thromboemboism. The lung involvement of Behçet's syndrome is uncommon but is one of the most serious prognostic factors of the disease. Therefore, an aggressive diagnostic work-up for early detection and proper treatment are recommended to improve the clinical course and the survival.

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The Spatio-temporal Distribution of Organic Matter on the Surface Sediment and Its Origin in Gamak Bay, Korea (가막만 표층퇴적물중 유기물량의 시.공간적 분포 특성)

  • Noh Il-Hyeon;Yoon Yang-Ho;Kim Dae-Il;Park Jong-Sick
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.1
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    • pp.1-13
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    • 2006
  • A field survey on the spatio-temporal distribution characteristics and origins of organic matter in surface sediments was carried out monthly at six stations in Gamak Bay, South Korea from April 2000 to March 2002. The range of ignition loss(IL) was $4.6{\sim}11.6%(7.1{\pm}1.6%)$, while chemical oxygen demand(CODs) ranged from $12.25{\sim}99.26mgO_2/g-dry(30.98{\pm}19.09mgO_2/g-dry)$, acid volatile sulfide(AVS) went from no detection(ND)${\sim}10.29mgS/g-dry(1.02{\pm}0.58mgS/g-dry)$, and phaeopigment was $6.84{\sim}116.18{\mu}g/g-dry(23.72{\pm}21.16{\mu}g/g-dry)$. The ranges of particulate organic carbon(POC) and particulate organic nitrogen(PON) were $5.45{\sim}23.24 mgC/g-dty(10.34{\pm}4.40C\;mgC/g-dry)$ and $0.71{\sim}2.99mgN/g-dry(1.37{\pm}0.58mgN/g-dry)$, respectively. Water content was in the range of $43.1{\sim}77.6%(55.8{\pm}5.6%)$, and mud content(silt+clay) was higher than 95% at all stations. The spatial distribution of organic matter in surface sediments was greatly divided between the northwestern, central and eastern areas, southern entrance area from the distribution characteristic of their organic matters. The concentrations of almost all items were greater at the northwestern and southern entrance area than at the other areas in Gamak Bay. In particular, sedimentary pollution was very serious at the northwestern area, because the area had an excessive supply of organic matter due to aquaculture activity and the inflow of sewage from the land. These materials stayed longer because of the topographical characteristics of such as basin and the anoxic conditions in the bottom seawater environment caused by thermocline in the summer. The tendency of temporal change was most prominently in the period of high-water temperatures than low-water ones at the northwestern and southern entrance areas. On the other hand, the central and eastern areas did not show a regular trend for changing the concentrations of each item but mainly showed a higher tendency during the low-water temperatures. This was observed for all but AVS concentrations which were higher during the period of high-water temperature at all stations. Especially, the central and eastern areas showed a large temporal increase of AVS concentration during those periods of high-water temperature where the concentration of CODs was in excess of $20mgO_2/g-dry$. The results show that the organic matters in surface sediments in Gamak Bay actually originated from autochthonous organic matters with eight or less in average C/N ratio including the organic matters generated by the use of ocean, rather than terrigenous organic matters. However, the formation of autochthonous organic matter was mainly derived from detritus than living phytoplankton, indicated the results of the POC/phaeopigment ratio. In addition, the CODs/IL ratio results demonstrate that the detritus was the product of artificial activities such as dregs feeding and fecal pellets of farm organisms caused by aquaculture activities rather than the dynamic of natural ocean activities.

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Correlation between High-Resolution CT and Pulmonary Function Tests in Patients with Emphysema (폐기종환자에서 고해상도 CT와 폐기능검사와의 상관관계)

  • Ahn, Joong-Hyun;Park, Jeong-Mee;Ko, Seung-Hyeon;Yoon, Jong-Goo;Kwon, Soon-Seug;Kim, Young-Kyoon;Kim, Kwan-Hyoung;Moon, Hwa-Sik;Park, Sung-Hak;Song, Jeong-Sup
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.3
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    • pp.367-376
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    • 1996
  • Background : The diagnosis of emphysema during life is based on a combination of clinical, functional, and radiographic findings, but this combination is relatively insensitive and nonspecific. The development of rapid, high-resolution third and fourth generation CT scanners has enabled us to resolve pulmonary parenchymal abnormalities with great precision. We compared the chest HRCT findings to the pulmonary function test and arterial blood gas analysis in pulmonary emphysema patients to test the ability of HRCT to quantify the degree of pulmonary emphysema. Methods : From october 1994 to october 1995, the study group consisted of 20 subjects in whom HRCT of the thorax and pulmonary function studies had been obtained at St. Mary's hospital. The analysis was from scans at preselected anatomic levels and incorporated both lungs. On each HRCT slice the lung parenchyma was assessed for two aspects of emphysema: severity and extent. The five levels were graded and scored separately for the left and right lung giving a total of 10 lung fields. A combination of severity and extent gave the degree of emphysema. We compared the HRCT quantitation of emphysema, pulmonary function tests, ABGA, CBC, and patients characteristics(age, sex, height, weight, smoking amounts etc.) in 20 patients. Results : 1) There was a significant inverse correlation between HRCT scores for emphysema and percentage predicted values of DLco(r = -0.68, p < 0.05), DLco/VA(r = -0.49, p < 0.05), FEV1(r = -0.53, p < 0.05), and FVC(r = -0.47, p < 0.05). 2) There was a significant correlation between the HRCT scores and percentage predicted values of TLC(r = 0.50, p < 0.05), RV(r = 0.64, p < 0.05). 3) There was a significant inverse correlation between the HRCT scores and PaO2(r = -0.48, p < 0.05) and significant correlation with D(A-a)O2(r = -0.48, p < 0.05) but no significant correlation between the HRCT scores and PaCO2. 4) There was no significant correlation between the HRCT scores and age, sex, height, weight, smoking amounts in patients, hemoglobin, hematocrit, and wbc counts. Conclusion : High-Resolution CT provides a useful method for early detection and quantitating emphysema in life and correlates significantly with pulmonary function tests and arterial blood gas analysis.

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Twitter Issue Tracking System by Topic Modeling Techniques (토픽 모델링을 이용한 트위터 이슈 트래킹 시스템)

  • Bae, Jung-Hwan;Han, Nam-Gi;Song, Min
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.109-122
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    • 2014
  • People are nowadays creating a tremendous amount of data on Social Network Service (SNS). In particular, the incorporation of SNS into mobile devices has resulted in massive amounts of data generation, thereby greatly influencing society. This is an unmatched phenomenon in history, and now we live in the Age of Big Data. SNS Data is defined as a condition of Big Data where the amount of data (volume), data input and output speeds (velocity), and the variety of data types (variety) are satisfied. If someone intends to discover the trend of an issue in SNS Big Data, this information can be used as a new important source for the creation of new values because this information covers the whole of society. In this study, a Twitter Issue Tracking System (TITS) is designed and established to meet the needs of analyzing SNS Big Data. TITS extracts issues from Twitter texts and visualizes them on the web. The proposed system provides the following four functions: (1) Provide the topic keyword set that corresponds to daily ranking; (2) Visualize the daily time series graph of a topic for the duration of a month; (3) Provide the importance of a topic through a treemap based on the score system and frequency; (4) Visualize the daily time-series graph of keywords by searching the keyword; The present study analyzes the Big Data generated by SNS in real time. SNS Big Data analysis requires various natural language processing techniques, including the removal of stop words, and noun extraction for processing various unrefined forms of unstructured data. In addition, such analysis requires the latest big data technology to process rapidly a large amount of real-time data, such as the Hadoop distributed system or NoSQL, which is an alternative to relational database. We built TITS based on Hadoop to optimize the processing of big data because Hadoop is designed to scale up from single node computing to thousands of machines. Furthermore, we use MongoDB, which is classified as a NoSQL database. In addition, MongoDB is an open source platform, document-oriented database that provides high performance, high availability, and automatic scaling. Unlike existing relational database, there are no schema or tables with MongoDB, and its most important goal is that of data accessibility and data processing performance. In the Age of Big Data, the visualization of Big Data is more attractive to the Big Data community because it helps analysts to examine such data easily and clearly. Therefore, TITS uses the d3.js library as a visualization tool. This library is designed for the purpose of creating Data Driven Documents that bind document object model (DOM) and any data; the interaction between data is easy and useful for managing real-time data stream with smooth animation. In addition, TITS uses a bootstrap made of pre-configured plug-in style sheets and JavaScript libraries to build a web system. The TITS Graphical User Interface (GUI) is designed using these libraries, and it is capable of detecting issues on Twitter in an easy and intuitive manner. The proposed work demonstrates the superiority of our issue detection techniques by matching detected issues with corresponding online news articles. The contributions of the present study are threefold. First, we suggest an alternative approach to real-time big data analysis, which has become an extremely important issue. Second, we apply a topic modeling technique that is used in various research areas, including Library and Information Science (LIS). Based on this, we can confirm the utility of storytelling and time series analysis. Third, we develop a web-based system, and make the system available for the real-time discovery of topics. The present study conducted experiments with nearly 150 million tweets in Korea during March 2013.

The Effect of Pleural Thickening on the Impairment of Pulmonary Function in Asbestos Exposed Workers (석면취급 근로자에서 늑막비후가 폐기능에 미치는 영향)

  • Kim, Jee-Won;Ahn, Hyeong-Sook;Kim, Kyung-Ah;Lim, Young;Yun, Im-Goung
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.6
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    • pp.923-933
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    • 1995
  • Background: Pleural abnormality is the the most common respiratory change caused by asbestos dust inhalation and also develop other asbestos related disease after cessation of asbestos exposure. So we conducted epidemiologic study to investigate if the pleural abnormality is associated with pulmonary function change and what factors are influenced on pulmonary function impairment. Methods: Two hundred and twenty two asbestos workers from 9 industries using asbestos in Korea were selected to measure the concentration of sectional asbestos fiber. Ouestionnaire, chest X-ray, PFT were also performed. All the data were analyzed by student t-test and chi-square test using SAS. Regressional analysis was performed to evaluate important factors, for example smoking, exposure concentration, period and the existence of pleural thickening, affecting to the change of pulmonary function. Results: 1) All nine industries except two, airborn asbestos fiber concentration was less than an average permissible concentration. PFT was performed on 222 workers and the percentage of male was 88.3%, their mean age was $41{\pm}9$ years old, and the duration of asbestos exposure was $10.6{\pm}7.8$ yrs. 2) The chest X-ray showed normal(89.19%), pulmonary Tb(inactive)(2.7%), pleral thickening (7.66%), suspected reticulonodular shadow(0.9%). 3) The mean values of height, smoking status, concentration of asbestos fiberwere not different between the subjects with pleural thickening and others, but age, cumulative pack-years, the duration of asbestos exposure were higher in subjects with pleural thickening. 4) All the PFT indices were lower in the subjects with pleural thickening than in the subjects without pleural thickening. 5) Simple regression analysis showed there was a significant correlation between $FEF_{75}$ which is sensitive in small airway obstruction and cumulative smoking pack-years, the duration of asbestos exposure and the concentration of asbestos fiber. 6) Multiple regression analysis showed all the pulmonary function indices were decreased as the increase of cumulative smoking pack-years and especially in the indices those are sensitive in small airway obstruction. Pleural thickening was associated with reduction in FVC, $FEV_1$, PEFR and $FEF_{25}$. Conclusion: The more concentration of asbestos fiber and the more duration of asbestos exposure, the greater reduction in $FEF_{50}$, $FEF_{75}$. Therefore PFT was important in the evaluation of early detection for small airway obstruction. Furthermore pleural thickening without asbesto-related parenchymal lung disease is associated with reduction in pulmonary function.

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Human Parathyroid Hormone-Related Peptide Measurement in the Lung Cancer Patients (폐암환자에서 인체 부갑상선 호르몬 관련 단백에 대한 연구)

  • Chang, Joon;Kim, Se-Kyu;Lim, Sung-Kil;Lee, Hong-Lyeol;Kim, Sung-Kyu;Lee, Won-Young
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.6
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    • pp.855-861
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    • 1995
  • Background: Parathyroid hormone-related protein(PTHrp) was first identified as the cause of hypercalcemia in malignancy. Hypercalcemia can be found in malignancy, especially in the epidermoid carcinoma of the lung, even without extensive metastases to the bones. The application of sensitive assays for PTHrp may help in the early diagnosis of lung cancer, in the monitoring of treatment and in the detection of recurrence. Method: Serum PTHrp was measured by radioimmunoassay detecting the N-terminal 1~34 peptide of human PTHrp(PTHrp 1-34) in 63 histologically confirmed lung cancer patients and 22 healthy controls. Result: Serum PTHrp(mean$\pm$S.E.) was $312{\pm}68.9pg/ml$ in 63 lung cancer patients and $158{\pm}38.2pg/ml$ in 22 controls(p>0.05). PTHrp was $356{\pm}103.9pg/ml$ in 34 epidermoid carcinoma patients, $281{\pm}148.7pg/ml$ in 15 adenocarcinoma patients and $316{\pm}140.8pg/ml$ in 9 small cell carcinoma patients. In epidermoid carcinoma patients, PTHrp was $570{\pm}472.3pg/ml$ in stage II(n=3; p<0.05 vs controls), $166{\pm}22.4pg/ml$ in stage IIIa(n=9), $282{\pm}113.3pg/ml$ in stage IIIb(n=12) and $668{\pm}367.9pg/ml$ in stage IV(n=9; p<0.05 vs controls). PTHrp was significantly increased in 8 epidermoid carcinoma patients with bone metastases($1526{\pm}811.2\;pg/ml$; p<0.0005 vs controls). Hypercalcemia was observed in an epidermoid carcinoma patient whose PTHrp value was 244 pg/ml. Conclusion: The serum PTHrp was increased in advanced epidermoid carcinoma patients even without hypercalcemia. The measurement of PTHrp may be not helpful in the early diagnosis of lung cancer. But the lung cancer should be suspected in the marked elevation of PTHrp. It may be of value in detecting patients of advanced diseases with bone metastases or patients who might develop the malignancy associated hypercalcemia.

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Analysis of Twitter for 2012 South Korea Presidential Election by Text Mining Techniques (텍스트 마이닝을 이용한 2012년 한국대선 관련 트위터 분석)

  • Bae, Jung-Hwan;Son, Ji-Eun;Song, Min
    • Journal of Intelligence and Information Systems
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    • v.19 no.3
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    • pp.141-156
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    • 2013
  • Social media is a representative form of the Web 2.0 that shapes the change of a user's information behavior by allowing users to produce their own contents without any expert skills. In particular, as a new communication medium, it has a profound impact on the social change by enabling users to communicate with the masses and acquaintances their opinions and thoughts. Social media data plays a significant role in an emerging Big Data arena. A variety of research areas such as social network analysis, opinion mining, and so on, therefore, have paid attention to discover meaningful information from vast amounts of data buried in social media. Social media has recently become main foci to the field of Information Retrieval and Text Mining because not only it produces massive unstructured textual data in real-time but also it serves as an influential channel for opinion leading. But most of the previous studies have adopted broad-brush and limited approaches. These approaches have made it difficult to find and analyze new information. To overcome these limitations, we developed a real-time Twitter trend mining system to capture the trend in real-time processing big stream datasets of Twitter. The system offers the functions of term co-occurrence retrieval, visualization of Twitter users by query, similarity calculation between two users, topic modeling to keep track of changes of topical trend, and mention-based user network analysis. In addition, we conducted a case study on the 2012 Korean presidential election. We collected 1,737,969 tweets which contain candidates' name and election on Twitter in Korea (http://www.twitter.com/) for one month in 2012 (October 1 to October 31). The case study shows that the system provides useful information and detects the trend of society effectively. The system also retrieves the list of terms co-occurred by given query terms. We compare the results of term co-occurrence retrieval by giving influential candidates' name, 'Geun Hae Park', 'Jae In Moon', and 'Chul Su Ahn' as query terms. General terms which are related to presidential election such as 'Presidential Election', 'Proclamation in Support', Public opinion poll' appear frequently. Also the results show specific terms that differentiate each candidate's feature such as 'Park Jung Hee' and 'Yuk Young Su' from the query 'Guen Hae Park', 'a single candidacy agreement' and 'Time of voting extension' from the query 'Jae In Moon' and 'a single candidacy agreement' and 'down contract' from the query 'Chul Su Ahn'. Our system not only extracts 10 topics along with related terms but also shows topics' dynamic changes over time by employing the multinomial Latent Dirichlet Allocation technique. Each topic can show one of two types of patterns-Rising tendency and Falling tendencydepending on the change of the probability distribution. To determine the relationship between topic trends in Twitter and social issues in the real world, we compare topic trends with related news articles. We are able to identify that Twitter can track the issue faster than the other media, newspapers. The user network in Twitter is different from those of other social media because of distinctive characteristics of making relationships in Twitter. Twitter users can make their relationships by exchanging mentions. We visualize and analyze mention based networks of 136,754 users. We put three candidates' name as query terms-Geun Hae Park', 'Jae In Moon', and 'Chul Su Ahn'. The results show that Twitter users mention all candidates' name regardless of their political tendencies. This case study discloses that Twitter could be an effective tool to detect and predict dynamic changes of social issues, and mention-based user networks could show different aspects of user behavior as a unique network that is uniquely found in Twitter.