• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.172-176
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• 2010

Purpose: The patients' moves occurred at PET/CT scan will cause the decline of correctness in results by resulting in inconsistency of Attenuation Correction (AC) and effecting on quantitative evaluation. This study has evaluated the utility of reconstruction method using AC position changing method when having inconsistency of AC depending on the position change of emission scan after transmission scan in obtaining PET/CT 3D image. Materials and Methods: We created 1 mL syringe injection space up to ${\pm}2$, 6, 10 cm toward x and y axis based on central point of polystyrene ($20{\times}20110$ cm) into GE Discovery STE16 equipment. After projection of syringe with $^{18}F$-FDG 5 kBq/mL, made an emission by changing the position and obtained the image by using AC depending on the position change. Reconstruction method is an iteration reconstruction method and is applied two times of iteration and 20 of subset, and for every emission data, decay correction depending on time pass is applied. Also, after setting ROI to the position of syringe, compared %Difference (%D) at each position to radioactivity concentrations (kBq/mL) and central point. Results: Radioactivity concentrations of central point of emission scan is 2.30 kBq/mL and is indicated as 1.95, 1.82 and 1.75 kBq/mL, relatively for +x axis, as 2.07, 1.75 and 1.65 kBq/mL for -x axis, as 2.07, 1.87 and 1.90 kBq/mL for +y axis and as 2.17, 1.85 and 1.67 kBq/mL for -y axis. Also, %D is yield as 15, 20, 23% for +x axis, as 9, 23, 28% for -x axis, as 12, 21, 20% for +y axis and as 8, 22, 29% for -y axis. When using AC position changing method, it is indicated as 2.00, 1.95 and 1.80 kBq/mL, relatively for +x axis, as 2.25, 2.15 and 1.90 kBq/mL for -x axis, as 2.07, 1.90 and 1.90 kBq/mL for +y axis, and as 2.10, 2.02, and 1.72 kBq/mL for -y axis. Also, %D is yield as 13, 15, 21% for +x axis, as 2, 6, 17% for -x axis, as 9, 17, 17% for +y axis, and as 8, 12, 25% for -y axis. Conclusion: When in inconsistency of AC, radioactivity concentrations for using AC position changing method increased average of 0.14, 0.03 kBq/mL at x, y axis and %D was improved 6.1, 4.2%. Also, it is indicated that the more far from the central point and the further position from the central point under the features that spatial resolution is lowered, the higher in lowering of radioactivity concentrations. However, since in actual clinic, attenuation degree increases more, it is considered that when in inconsistency, such tolerance will be increased. Therefore, at the lesion of the part where AC is not inconsistent, the tolerance of radioactivity concentrations will be reduced by applying AC position changing method.

• Journal of agricultural medicine and community health
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• v.29 no.1
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• pp.101-119
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• 2004

Objectives: In order to estimate risk factors affecting the health of vinylhouse workers and harmful environments in vinylhouse working. Methods: The investigator performed questionnaires and laboratory examinations on 102 vinylhouse workers and 69 farmers in 7 myoens (Korean subcounties). one eup (a Korean town), Goryeong-gun, Gyeongsangbuk-do between April 8 and 18, 2004 (for 11 days), and measured the heavy metal in the air and the soil, temperature, humidity, air current, harmful gases in vinylhouses. Results: Even in cloudy days, the temperature in vinylhouses in daylight was $33.4^{\circ}$ and the temperature difference between inside and outside vinylhouses was around $16^{\circ}$. Oxygen concentration was similar inside and outside vinylhouses, while carbon dioxide concentration was lower inside than outside vinylhouses. Carbon monoxide was not detected. In the air inside vinylhouses, cadmium was not detected. Lean concentration in the soil was lower inside vinylhouses than outside vinylhouses at surface, while cadmium concentration was similar inside and outside vinylhouses in the soil except some areas. Out of male vinylhouse workers. 16.4---- were positive farmer's syndrome and 49.2---- were suspicious, while out of females, 41.5---- were positive and 46.3---- were suspicious. Out of male farmers, 30.4---- were positive farmer's syndrome, while out of female farmers, 60.0---- were positive and 28.3---- were suspicious. There was no difference between vinylhouse workers and farmers in the distribution of hypertension and abnormal liver function, while diabetes mellitus was more common in farmers than in vinylhouse workers. Vinylhouse working, sex, and hours of farming per day were selected as significant variables affecting farmer's syndrome in this study, and the rate of positive farmer's syndrome was rather lower in vinylhouse workers than in farmers. Females were higher than males in the rate, and those who farmed at least 10 hours per day were higher in the rate than those who farmed less than 10 hours per day. Out of the vinylhouse workers, no differences were found between the distribution of farmer's syndrome and farming-related variables such as the total period of farming, the size of farm land, the mean farming hours per day, the number of family members who farm together, the frequency of scattering agricultural chemicals. In addition, there were no differences between the distribution and the wearing masks and protectors and personal sanitation among those who scattered agricultural chemicals by themselves. There were no differences found in blood lean concentration, urinary cadmium concentration, serum cholinesterase, and hemoglobin according to the distribution of farmer's syndrome. In the vinylhouse workers, females were higher than males in the rate of farmer's syndrome, and those who farmed at least 10 hours per day were higher in the rate than those who farmed less than 10 hours per day. Meanwhile, the rate was lower in those who slept at least 8 hours a day than in those who slept less than 8 hours. Conclusions: In conclusion, the physical environments inside vinylhouses were harmful, but no significant difference was found in harmfulness of the chemical environments. The chronic diseases such as farmer's syndrome. hypertension, diabetes, and dyshepatia were not common in the vinylhouse workers than in the farmers. Meanwhile, farmer's syndrome was more common in the vinylhouse workers who worked longer and slept less.

• Journal of Chest Surgery
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• v.31 no.10
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• pp.939-944
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• 1998

Background: The sugical results of the Cox-Maze procedure (CMP) for lone atrial fibrillation(AF) have proven to be exellent. However, those for AF associated with mitral valve(MV) disease have been reported to be a little inferior. Materials and methods: To assess the efficacy and safety of the CMP as a combined procedure with MV operation, we studied retrospectively our experiences. Between April 1994 and October 1997, we experienced 70 (23 males, 47 females) cases of CMP concomitantly with MV operation. Results: The etiologies of MV disease were rheumatic in 67 and degenerative in 3 cases. The mean duration of AF before sugery was 66$\pm$70 months. Fifteen patients had the past medical history of thromboembolic complications, and left atrial thrombi were identified at operation in 24 patients. Twelve cases were reoperations. Aortic cross clamp (ACC) time was mean 151$\pm$44 minutes, and cardiopulmonary bypass (CPB) time was mean 246$\pm$65 minutes. Concomitant procedures were mitral valve replacement (MVR) in 19, MVR and aortic valve replacement (AVR) in 14, MVR and tricupid annuloplasty (TAP) in 8, MVR with AV repair in 3, MV repair in 11, MVR and coronary artery bypass grafting (CABG) in 2, MVR and AVR and CABG in 1, redo-MVR in 10, redo-MVR and redo-AVR in 2 patients. The rate of hospital mortality was 1.4%(1/70). Perioperative recurrence of AF was seen in 44(62.9%), and atrial tachyarrhythmias in 10(14.3%), low cardiac output syndrome in 4(5.7%), postoperative bleeding that required mediastinal exploration in 4(5.7%) patients. Other complications were acute renal failure in 2, aggravation of preoperative hemiplegia in 1, and transient delirium in 1 patient. We followed up all the survivors for 16.4 months(3-44months) on an average. Sinus rhythm has been restored in 65(94.2%) patients. AF has been controlled by operation alone in 73.9% and operation plus medication in 20.3%. Two patients needed permanent pacemaker implantation; one with sick sinus syndrome, and the other with tachycardia- bradycardia syndrome. Only two patients remained in AF. We followed up our patients with transthoracic echocardiography to assess the atrial contractilities and other cardiac functions. Right atrial contractility could be demonstrated in 92% and left atrial contractility in 53%.We compared our non-redo cases with redo cases. Although the duration of AF was significantly longer in redo cases, there was no differences in ACC time, CPB time, postoperative bleeding amount and sinus conversion rate. Conclusions: In conclusion, the CMP concomitant with MV operation demonstrated a high sinus conversion rate under the acceptable operative risk even in case of reoperation.

• Progress in Medical Physics
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• v.21 no.1
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• pp.52-59
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• 2010

To examine among patients with vertebral compression fracture the extent to which signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values at the lumbar vertebral compression fracture site vary on diffusion-weighted MR images according to varying b values on the 1.5T MR device. Diffusion-weighted MR images of 30 patients with compression fracture due to chronic osteoporosis who underwent vertebral MRI from Jan. 2008 to Nov. 2009 were respectively obtained using a 1.5-T MR scanner with the b values increased from 400, 600, 800, 1,000 to $1,200\;s/mm^2$. For diffusion-weighted MR images with different b values, the signal-to-noise ratio (SNR) was assessed at three sites: the site of compression fracture of the lumbar vertebral body at L1 to L5, and both the upper and lower discs of the said fracture site, while for ADC map images with different b values, the SNR and ADC were respectively assessed at those three sites. As a quantitative analysis, diffusion-weighted MR images and ADC map images with b value of $400\;s/mm^2$ (the base b values) were respectively compared with the corresponding images with each different b value. As far as qualitative analysis is concerned, for both diffusion-weighted MR and ADC map images with b value of $400\;s/mm^2$, the extent to which signal intensity values obtained at the site of compression fracture of the lumbar vertebral body at L1 to L5 vary according to the increasing b values were examined. The quantitative analysis found that for both diffusion-weighted MR and ADC map images, as the b values increased, the SNR were relatively lowered at all the three sites, compared to the base b value. Also, it was found that as the b values increased, ADC valueswere relatively lowered at all the three sites on ADC map images. On the other hand, the qualitative analysis found that as the b values increased to more than $400\;s/mm^2$, the signal intensity gradually decreased at all the sites, while at the levels of more than $1,000\;s/mm^2$, severe image noises appeared at all of the three sites. In addition, higher signal intensity was found at the site of compression fracture of the lumbar vertebral body than at the discs. Findings showed that with the b value being increased, both the signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values gradually decreased at all the sites of the lumbar vertebral compression fracture and both the upper and lower discs of the fracture site, suggesting that there is a possibility of a wider range of applications to assessment of various vertebral pathologies by utilizing multi b values in the diffusion-weighted MRI examination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.131-138
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• 1985

The preservative effect of modified-atmosphere storage on the shelf-life of packed semi-salted and dried mackerel, Scomber japonicus, was examined. The semi-salted and dried mackerel fillets were packed in laminated plastic film bags (polyester/nylon/casted polypropylene: $12{\mu}m/15{\mu}m/60{\mu}m,\;15{\times}16cm$) filled with air (control, C), nitrogen gas (N), deoxygenized air (O) prepared by using free-oxygen absorber enclosed in the bag, in vacuum(V), and stored at $5^{\circ}C$. The quality of packed sample during the storage were examined in terms of viable cell counts of bacteria, thiobarbituric acid(TBA) value, perozide value(POV), volatile basic nitrogen(VBN), trimethylamine(TMA), adenosine triphosphate(ATP) and its related compounds and sensory evaluation. The results obtained are as follows: The pH of all the samples was in the range of $6.1{\pm}0.2$, and the contents of VBN and amino nitrogen of them increased during storage. In color values, L value(lightness) decreased while a and b values (red and yellow) revealed a tendency to increase during storage. The viable cell counts of the control sample(C) increased to $3.0{\times}10^6/g$ after 15 days storage but those of the other samples(V, N and O)were in the range of $2{\sim}6{\times}10^5/g$ after 20 days storage. The content of TMA increased during storage, but the histamine content showed a little change during storage and its content of all samples were less than 16 mg/100g. The inosinic acid(IMP) was rapidly degraded while inosine and hypoxanthine increased during storage. The TBA value of the control(C) reached a peak in 9 days and then decreased gradually while that of the sample(O) showed a little change during storage. The changes in POV of all the samples during storage showed a similar tendency to the TBA value. Fatty acid composition of raw mackerel consists of $35.6\%$ of saturated acid, $30.3\%$ of monoenoic acid and $34.2\%$ of polyenoic acid. The major fatty acid of the sample products were oleic acid($C_{18:1}$), palmitic acid($C_{16:0}$), docosahexaenoic acid($C_{22:6}$). The contents of polyenoic acid such as $C_{22:6},\;C_{20:5}$ decreased during storage while the other fatty acids showed a little change. From the results of sensory evaluation, the shelf-life of the control sample(C) was about 7 days and that of sample(V), (N) and (O) was about 15 days. It was concluded that deoxygenized atmosphere(free-oxygen absorber enclosed in the bag) was a good condition for preserving the quality of semi-salted and dried mackerel.

• Journal of Intelligence and Information Systems
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• v.21 no.2
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• pp.69-92
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• 2015

The explosion of social media data has led to apply text-mining techniques to analyze big social media data in a more rigorous manner. Even if social media text analysis algorithms were improved, previous approaches to social media text analysis have some limitations. In the field of sentiment analysis of social media written in Korean, there are two typical approaches. One is the linguistic approach using machine learning, which is the most common approach. Some studies have been conducted by adding grammatical factors to feature sets for training classification model. The other approach adopts the semantic analysis method to sentiment analysis, but this approach is mainly applied to English texts. To overcome these limitations, this study applies the Word2Vec algorithm which is an extension of the neural network algorithms to deal with more extensive semantic features that were underestimated in existing sentiment analysis. The result from adopting the Word2Vec algorithm is compared to the result from co-occurrence analysis to identify the difference between two approaches. The results show that the distribution related word extracted by Word2Vec algorithm in that the words represent some emotion about the keyword used are three times more than extracted by co-occurrence analysis. The reason of the difference between two results comes from Word2Vec's semantic features vectorization. Therefore, it is possible to say that Word2Vec algorithm is able to catch the hidden related words which have not been found in traditional analysis. In addition, Part Of Speech (POS) tagging for Korean is used to detect adjective as "emotional word" in Korean. In addition, the emotion words extracted from the text are converted into word vector by the Word2Vec algorithm to find related words. Among these related words, noun words are selected because each word of them would have causal relationship with "emotional word" in the sentence. The process of extracting these trigger factor of emotional word is named "Emotion Trigger" in this study. As a case study, the datasets used in the study are collected by searching using three keywords: professor, prosecutor, and doctor in that these keywords contain rich public emotion and opinion. Advanced data collecting was conducted to select secondary keywords for data gathering. The secondary keywords for each keyword used to gather the data to be used in actual analysis are followed: Professor (sexual assault, misappropriation of research money, recruitment irregularities, polifessor), Doctor (Shin hae-chul sky hospital, drinking and plastic surgery, rebate) Prosecutor (lewd behavior, sponsor). The size of the text data is about to 100,000(Professor: 25720, Doctor: 35110, Prosecutor: 43225) and the data are gathered from news, blog, and twitter to reflect various level of public emotion into text data analysis. As a visualization method, Gephi (http://gephi.github.io) was used and every program used in text processing and analysis are java coding. The contributions of this study are as follows: First, different approaches for sentiment analysis are integrated to overcome the limitations of existing approaches. Secondly, finding Emotion Trigger can detect the hidden connections to public emotion which existing method cannot detect. Finally, the approach used in this study could be generalized regardless of types of text data. The limitation of this study is that it is hard to say the word extracted by Emotion Trigger processing has significantly causal relationship with emotional word in a sentence. The future study will be conducted to clarify the causal relationship between emotional words and the words extracted by Emotion Trigger by comparing with the relationships manually tagged. Furthermore, the text data used in Emotion Trigger are twitter, so the data have a number of distinct features which we did not deal with in this study. These features will be considered in further study.

• Journal of Intelligence and Information Systems
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• v.17 no.3
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• pp.63-77
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• 2011

The World Wide Web is a very large distributed digital information space. From its origins in 1991, the web has grown to encompass diverse information resources as personal home pasges, online digital libraries and virtual museums. Some estimates suggest that the web currently includes over 500 billion pages in the deep web. The ability to search and retrieve information from the web efficiently and effectively is an enabling technology for realizing its full potential. With powerful workstations and parallel processing technology, efficiency is not a bottleneck. In fact, some existing search tools sift through gigabyte.syze precompiled web indexes in a fraction of a second. But retrieval effectiveness is a different matter. Current search tools retrieve too many documents, of which only a small fraction are relevant to the user query. Furthermore, the most relevant documents do not nessarily appear at the top of the query output order. Also, current search tools can not retrieve the documents related with retrieved document from gigantic amount of documents. The most important problem for lots of current searching systems is to increase the quality of search. It means to provide related documents or decrease the number of unrelated documents as low as possible in the results of search. For this problem, CiteSeer proposed the ACI (Autonomous Citation Indexing) of the articles on the World Wide Web. A "citation index" indexes the links between articles that researchers make when they cite other articles. Citation indexes are very useful for a number of purposes, including literature search and analysis of the academic literature. For details of this work, references contained in academic articles are used to give credit to previous work in the literature and provide a link between the "citing" and "cited" articles. A citation index indexes the citations that an article makes, linking the articleswith the cited works. Citation indexes were originally designed mainly for information retrieval. The citation links allow navigating the literature in unique ways. Papers can be located independent of language, and words in thetitle, keywords or document. A citation index allows navigation backward in time (the list of cited articles) and forwardin time (which subsequent articles cite the current article?) But CiteSeer can not indexes the links between articles that researchers doesn't make. Because it indexes the links between articles that only researchers make when they cite other articles. Also, CiteSeer is not easy to scalability. Because CiteSeer can not indexes the links between articles that researchers doesn't make. All these problems make us orient for designing more effective search system. This paper shows a method that extracts subject and predicate per each sentence in documents. A document will be changed into the tabular form that extracted predicate checked value of possible subject and object. We make a hierarchical graph of a document using the table and then integrate graphs of documents. The graph of entire documents calculates the area of document as compared with integrated documents. We mark relation among the documents as compared with the area of documents. Also it proposes a method for structural integration of documents that retrieves documents from the graph. It makes that the user can find information easier. We compared the performance of the proposed approaches with lucene search engine using the formulas for ranking. As a result, the F.measure is about 60% and it is better as about 15%.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.54-65
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• 2003

Purpose : To analyze the gene expression Profiles of uterine ceulcal cancer, and its variation after radiation therapy, with or without concurrent chemotherapy, using a CDNA microarray. Materials and Methods :Sixteen patients, 8 with squamous ceil carcinomas of the uterine cervix, who were treated with radiation alone, and the other 8 treated w14h concurrent chemo-radiation, were Included in the study. Before the starling of the treatment, tumor biopsies were carried out, and the second time biopsies were peformed after a radiation dose of 16.2$\~$27 Gy. Three normal cervix tissues were used as a control group. The microarray experiments were peformed with 5 groups of the total RNAs extracted individually and then admixed as control, pre-radiation therapy alone, during-radiation therapy alone, pre-chemoradiation therapy, and during-chemoradlation therapy. The 33P-iabeled CDNAS were synthesized from the total RNAs of each group, by reverse transcription, and then they were hybridized to the CDNA microarray membrane. The gene expression of each microarrays was captured by the intensity of each spot produced by the radioactive isotopes. The pixels per spot were counted with an Arrayguage, and were exported to Microsoft Excel The data were normalized by the Z transformation, and the comparisons were peformed on the Z-ratio values calculated. Results : The expressions of 15 genes, including integrin linked kinase (ILK), CDC28 protein kinase 2, Spry 2, and ERK 3, were increased with the Z-ratio values of over 2.0 for the cervix cancer tissues compared to those for the normal controls. Those genes were involved In cell growth and proliferation, cell cycle control, or signal transduction. The expressions of the other 6 genes, Including G protein coupled receptor kinase 5, were decreased with the Z-ratio values of below -2.0. After the radiation thorapy, most of the genes, with a previously Increase expressions, represented the decreased expression profiles, and the genes, with the Z-ratio values of over 2.0, were cyclic nucleotlde gated channel and 3 Expressed sequence tags (EST). In the concurrent chemo-radiation group, the genes involved in cell growth and proliferation, cell cycle control, and signal transduction were shown to have increased expressions compared to the radiation therapy alone group. The expressions of genes involved in anglogenesis (angiopoietln-2), immune reactions (formyl peptide receptor-iike 1), and DNA repair (CAMP phosphodiesterase) were increased, however, the expression of gene involved In apoptosls (death associated protein kinase) was decreased. Conclusion : The different kinds of genes involved in the development and progression of cervical cancer were identified with the CDNA microarray, and the proposed theory is that the proliferation signal stalls with ILK, and is amplified with Spry 2 and MAPK signaling, and the cellular mitoses are Increased with the increased expression oi Cdc 2 and cell division kinases. After the radiation therapy, the expression profiles demonstrated 4he evidence of the decreased cancer cell proliferation. There was no sigificant difference in the morphological findings of cell death between the radiation therapy aione and the chemo-radiation groups In the second time biopsy specimen, however, the gene expression profiles were markedly different, and the mechanism at the molecular level needs further study.

• Journal of Gastric Cancer
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• v.5 no.2
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• pp.89-94
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• 2005

Purpose: Early gastric cancer (EGC) has an excellent prognosis compared to advanced gastric cancer. The 5-year survival rate for EGC now exceeds $90\%$, and EGC is recognized as a curable malignancy. The important prognostic factor in EGC is the status of lymph-node metastasis. Despite conserving surgery being suggested for EGC at present, it is of vital importance to select a surgical method appropriate to each individual case. This retrospective study was undertaken to clarify clinicopathologic features and factors related to lymph-node metastasis in submucosal gastric cancer in order to determine an appropriate therapy. Materials and Methods: This study analyzed the clinicopathologic features for 279 patients with a submucosal gastric carcinoma (Group I) and compared with those of patients with mucosal (Group II) or muscularis proprial gastric carcinoma (Group III). All patients were operated on from 1981 to 1999 at Chonnam University Hospital. There were no statistically significant differences among the groups with respect to age, gender, tumor location, hepatic metastasis, or peritoneal dissemination. Results: Positive lymph node metastasis was found in 47 ($16.8\%$) of the 279 patients with a submucosal gastric carcinoma. The incidence of lymph-node metastasis was significantly higher in patients with a submucosal gastric carcinoma than in patients with a mucosal gastric carcinoma ($16.8\%\;vs.\;3.9\%\;$; P<0.01). Therefore, depth of invasion was a significant factor affecting in lymph-node metastasis. The 5-year survival rates were $88.6\%$ for patients in Group I, $95.2\%$ for patients in Group II, and $72.7\%$ for patients in Group III (P<0.01 for Group I vs. Group II; Group I vs. Group III). In patients with a submucosal gastric carcinoma, the survival rate with positive lymph nodes was significantly poorer than that of patients without lymph-node metastasis ($87.3\%\;vs.\;94.2\%$; P<0.01). Conclusion: Gastrectomy with D2 lymph node dissection is an appropriate operative procedure for patients with a submucosal gastric carcinoma.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.766-772
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• 2000

Background : Pressure rise time (PRT) is the time in which the ventilator aclieves the set airway pressure in pressure-targeted modes, such as pressure control ventilation (PCV). With varying PRT, in principle, the peak inspiratory flow rate of the ventilator also varies. And if PRT is set to a shorter duration, the effective duration of target pressure level would be prolonged, which in turn would increase inspiratory tidal volume(Vti) and mean airway pressure (Pmean). We also postulated that the increase in Vti with shortening of PRT may relate inversely to the patients' basal airway resistance. Methods : In 13 paralyzed patients on PCV (pressure control 18$\pm$9.5 cm $H_2O$ $FIO_2\;0.6\pm0.3$, PEEP 5$\pm$3 cm $H_2O$, f 20/min, I : E1 : 2) with Servo 300 (Siemens-Elema, Solna, Sweden) from various causes of respiratory failure, PRT of 10 %, 5 % and 0 % were randomly applied. At 30 min of each PRT trial, peak inspiratory flow (PIF, L/sec), Vti (ml), Pmean (cm $H_2O$) and ABGA were determined. Results : At PRT 10%, 5%, and 0%, PIF were 0.69$\pm$0.13, 0.77$\pm$0.19, 0.83$\pm$0.22, respectively (p<0.001). Vti were 425$\pm$94, 439$\pm$101, 456$\pm$106, respectively (p<0.001), and Pmean were 11.2$\pm$3.7, 12.0$\pm$3.7, 12.5$\pm$3.8, respectively (p<0.001). pH were 7.40$\pm$0.08, 7.40$\pm$0.92, 7.41$\pm$0.96, respectively (p=0.00) ; $PaCO_2$ (mm Hg) were 47.4$\pm$15.8, 47.2 $\pm$15.7, 44.6$\pm$16.2, respectively (p=0.004) ; $PAO_2-PaO_2$ (mm Hg) were 220$\pm$98, 224$\pm$95, 227$\pm$94, respectively (p=0.004) ; and $V_n/V_T$ as determined by ($PaCO_2-P_E-CO_2$)/$PaCO_2$ were 0.67$\pm$0.07, 0.67$\pm$0.08, 0.66$\pm$0.08, respectively (p=0.007). The correlation between airway resistance and change of Vti from PRT 10% to 0% were r= -0.243 (p=0.498). Conclusion : Shortening of pressure rise timee during PCV was associated with increased tidal volume, increased mean airway pressure and lower $PaCO_2$.