• Science of Emotion and Sensibility
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• v.15 no.3
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• pp.389-398
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• 2012

Virtual worlds have pursued reality as if they actually exist. In order to evaluate the sense of reality in the computer-simulated worlds, several subjective questionnaires, which include specific independent variables, have been proposed in the literature. However, the questionnaires lack reliability and validity necessary for defining and measuring the virtual realization. Few studies have been conducted to investigate the effect of visual factors on the sense of reality experienced by exposing to a virtual environment. Therefore, this study was aimed at reinvestigating the variables and proposing a more reliable and advisable questionnaire for evaluating the virtual realization, focusing on visual factors. Twenty-one questions were gleaned from the literature and subjective interviews with focused groups. Exploratory factor analysis with oblique rotation was performed on the data obtained from 200 participants(females: 100) after exposing to a virtual character image described in an extreme way. After removing poorly loading items, remained subsets were subjected to confirmatory factor analysis on the data obtained from the same participants. As a result, 3 significant factors were determined to efficiently measure the virtual realization. The determined factors included visual presence(3 subset items), visual immersion(7 subset items), and visual interactivity(4 subset items). The proposed factors were verified by conducting a subjective evaluation in which participants were asked to evaluate a 3D virtual eyeball model based on the visual presence. The results implicated that the measurement method was suitable for evaluating the degree of the virtual realization. The proposed method is expected to reasonably measure the degree of the virtual realization.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.51-57
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• 2016

Acoustic noise during magnetic resonance imaging (MRI) is the main source for patient discomfort. we report our preliminary experience with this technique in neuroimaging with regard to subjective and objective noise levels and image quality. 60 patients(29 males, 31 females, average age of 60.1) underwent routine brain MRI with 3.0 Tesla (MAGNETOM Tim Trio; Siemens, Germany) system and 12-channel head coil. Q-$T_2$ and $T_2$ sequence were performed. Measurement of sound pressure levels (SPL) and heart rate on Q-$T_2$ and $T_2$ was performed respectively. Quantitative analysis was carried out by measuring the SNR, CNR, and SIR values of Q-$T_2$, $T_2$ and a statistical analysis was performed using independent sample T-test. Qualitative analysis was evaluated by the eyes for the overall quality image of Q-$T_2$ and $T_2$. A 5-point evaluation scale was used, including excellent(5), good(4), fair(3), poor(2), and unacceptable(1). The average noise and peak noise decreased by $15dB_A$ and $10dB_A$ on $T_2$ and Q-$T_2$ test. Also, the average value of heartbeat rate was lower in Q-$T_2$ for 120 seconds in each test, but there was no statistical significance. The quantitative analysis showed that there was no significant difference between CNR and SIR, and there was a significant difference (p<0.05) as SNR had a lower average value on Q-$T_2$. According to the qualitative analysis, the overall quality image of 59 case $T_2$ and Q-$T_2$ was evaluated as excellent at 5 points, and 1 case was evaluated as good at 4 points due to a motion artifact. Q-$T_2$ is a promising technique for acoustic noise reduction and improved patient comfort.

• Journal of Chest Surgery
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• v.19 no.1
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• pp.35-42
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• 1986

Prevention of thrombombolism after rosthetic cardiac valve replacement is essential for the patients. About 90% of patients are free of major and minor thromboembolic complications 5 year after replacement of cardiac valves with prosthetic devices when they are under control of anticoagulant therapy. Ticlopidine is a drug that alter platelet function to have an antithrombotic effect. It is an antiaggregating agent which inhibits primary platelet function to have an antithrombotic effect. It is an antiaggregating agent which inhibits primary platelet aggregation induced by ADP and increases the production of prostaglandin $D_{2}$. Aspirin in small doses inhibits platelet synthesis of prostaglandins by irreversibly blocking the enzyme cyclo-oxygenase. Platelet secretion and aggregation are impaired with Ticlopidine and Aspirin. the thromboembolic event sof 54 patient s who were treated with Ticlopidine and Aspirin after cardiac valve replacement were evaluated and compared with that of 79 patients who were treated with Wafarin and Aspirin after the same type of operation. The follow-up period ranged from 4 to 110 months (mean of 48 months). there were 11 major thromboembolic episodes including three deaths in the warfarin goup during mean follow-up period of 56 months. two cases of CVA and one hemoarthrosis were noted due to overdose of Warfarin. Inticlopidine group, there was only one fatal thromboembolic epdisode three month after mitral valve replacement during mean follow-up period of 18 months. Two episodes of hypermenorrhea resulting anemia ere noted in the ticlopidine group. We measured the parameters of platelet function in aggreagation curve of platelet with platelet aggregometer (chrono-log Aggregometer, Model No. 430) Aggregation test was performed with three final concentrations of epinephrine in 10 uM/L, ADP in 5uM/L. 28 patients with prosthetic cardiac valves and 35 healthy volunteers were subgrouped as follows to analyze the effect of antithrombotic drugs used. Group I ; 11 patients treated with 250-500 mg of ticlopidine and 0.5gm of Aspirin as a daily single dose after cardiac valve replacement (14 St. Jude Medical and 1 Carpentier-Edwards, 9 patients with atrial fibrillation among them) Group II ; 10 patients treated with 3-5 mg of Warfarin and 0.75 gm of Aspirin daily to prolong prothrombin time around 20 seconds for more than 6 months and single Aspirin dose was maintained afterward as a life-long regimes(3 St. Jude Medical, 1 Hall-Kaster and 7 Carpentier-Edwards valve, 9 patients in atrial fibrilation). Group III ; 7 patients who quit anticoagulant treatment (Warfarin + Aspirin) 6-12 months after the regime as group II (3 St. Jude Medical. 1 bjork-Shiley, 1 Hall-Kaster, 3 Carpentier-Edwards valve, 2 of them are with atrial fibrillation). Group IV ; 35 healthy vounteers (28 males and 7 females). The following results were obtained. 1. The mean maximal platelet aggregability in Group I induced by 10uM/L epinephrine was 15.6%, and 17.5 and 18.7% in BM in proportion to the induction by 5 and 10 uM/L ADP. 2. The mean maximal platelet aggregability in Group II induced by 10uM/L epinephrine was 16.5%, and 27.4 and 44.7% in BM in proportion to the induction by 5 and 10uM/L ADP. 3. The mean maximal platelet aggregability in group III induced by 10uM/L epinephrine was 65%, and 56.5 and 51.8% in BM in proportion to the induction by 5 and 10 uM/L ADP. 4. The mean maximal platelet aggregability in the normal subjects induced by 10 uM/L epinephrine was 64%, and 65 and 69% in Bm inproportion to the induction by 5 and 10 uM/L ADP. 5. Reversible change of platelet aggregation curve induced by 5 and 10uM/L was noted all of the patients in Group I. conclusion : Ticlopidine is an antiaggregating agent which inhibits primary platelet aggregation induced by ADP, and increases the production of prostaglandin $D_{2}$. Ticlopidine and Aspirin produced a significant inhibition of platelet in the presence of ADP and epinephrine in our study. Acccording to our brief experience, 250 mg of ticlopidine and low dose of Aspirin resulted synergistic superior effect to each drug alone in prevention of thromboembolism after prosthetic cardiac valve replacement.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.806-812
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• 1999

Background: Selection of reconstruction route in esophageal cancer surgery is based on the patient's status, characteristics of tumor, surgeon's preference and experience. Of the various routes, it has been documented that subcutaneous or substernal route may prolong operation time and may be vulnerable to postoperative respiratory complications. This study was designed to evaluate whether the selection of reconstruction route affects the surgical outcomes. Material and Method: Of 131 patients who have undergone resection and reconstruction for esophageal cancer, posterior mediastinal route(Group I, n=34), substernal route (Group II, n=31), and subcutaneous route(Group III, n=21) were retrospectively reviewed in 86 patients. Results of early operations and morbidities were compared between the groups. Result: There was a male prevalence(79 of males vs. 7 of females). There were 81 squamous cell cancers and 5 adenocarcinomas. There were no differences between groups in weight, height, age, cancer staging and location, and in the preoperative anesthetic risk evaluation and pulmonary function test(p=NS). Postoperative mechanical ventilation time was longer in Group I(20.6 hours) than in Group II(7.8 hours) or III(3.4 hours)(p=0.005). Duration of stay in the intensive care unit was prolonged in Group III(6.4 days) compared to Group I (3.9 days) or II(3.1 days)(p=0.043). No differences were noted in the duration of hospital stay between the groups(p=NS). Blood transfusion was needed in 30 out of 34 patients in Group I compared to 14/31 in Group II or 15/21 in Group III(p=0.001). The mean amount of transfusion for each patient was also higher in Group I(3,833 mL) than in Group II(1535 mL) or Group III(1419 mL)(p=0.04), but there was no difference in the inreoperation due to bleeding. Ea ly mortality rate was substantially higher in Group I(17.6%) but the differences between the groups were insignificant(p=NS). Although sepsis was a more prevalent cause of death in Group I, it was not related to anastomotic leak. Other morbidities did not differ between the groups(p=NS). Conclusion: In above results show that the reconstruction route does not affect the outcome of esophageal cancer surgery. We believe that the selection of reconstruction route can be based on the surgeon's preference and experience.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.420-427
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• 2007

Background: Postpneumonectomy empyema (PPE) due to bronchopleural fistula (BPF) can be a surgical challenge for surgeons. We analyzed the follow-up outcomes after performing omentopexy and thoracoplasty for the treatment of PPE with BPF after pneumonectomy. Material and Mehod: Between December 1991 and January 2006, 9 patients underwent BPF closure using an omental pedicled flap for the treatment of PPE with BPF after pneumonectomy. There were 7 males and 2 females (mean age: $45.9{\pm}9$ years). The patients were followed up for a mean of 58 months (median: 28 months, range: $6{\sim}169$). When we performed omentopexy, the surgical procedures for empyema were thoracoplasy for 8 patients and the Clagett procedure for 1 patient. Thoracoplasty was performed for the latter patient due to recurrence of empyema, Result: For the 8 patients who were treated by omentopexy and thoracoplasty, there was 1 operation-related death due to sepsis. During follow up, 1 patient, who was treated by omentopexy and a Clagett procedure, died of acute hepatitis 40 months postoperatively. The early mortality was 11.1% (8/9). Of the 8 patients, including the 1 late death patient, successful closure of the BPF were achieved in all patients (8/9) and the empyema was cured in 7 patients (7/8). Conclusion: The BPF closure using an omental pedicled flap was an effective method for treating PPE with BPF due to 75-destroyed lung, and thoracoplasty with simultaneous omentopexy was effective and safe for removing dead space if the patient was young and in a good general condition.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.36-43
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• 2011

Purpose: To evaluate the effectiveness of radiation therapy (RT) for hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) and to analyze the prognostic factors. Materials and Methods: From December 2004 to April 2009, 70 patients who had HCC with PVTT were treated with RT at Keimyung University Dongsan Medical Center. Nineteen patients whose total dose was below 30 Gy and one patient who underwent liver transplantation were excluded. The remaining 50 patients (45 males, 5 females; median age 55 years) were analyzed. According to the LCSGJ TNM stage, there were 27 patients (54.0%) with stage III and 23 (46.0%) with stage IV. Total dose of 30~54 Gy was administered (median 45). Thirty patients (60.0%) were treated with concurrent chemoradiation therapy (CCRT). The median follow-up duration was from 13.5 months (range, 3 to 70 months). Results: The median survival time from the start of RT was 9 months. One-year and 2-year overall survival rates were 24.9% and 11.2%, respectively. At the follow-up time, three patients (6.0%) displayed no evidence of disease. Seven patients (14.0%) were alive with disease, and 40 (80.0%) patients had expired due to disease progression. CCRT was associated with worse survival than RT alone (p=0.034), Response to RT (p=0.037), CLIP stage (p=0.017), and TNM stage (p=0.041) were statistically significant prognostic factors. There was no radiation-induced liver disease. Conclusion: RT is an effective and safe modality for HCC with PVTT. Further studies such as prospective randomized trials are needed to confirm the role of RT for HCC with PVTT.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.737-744
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• 2006

Purpose : To assess the usefulness of $^{99m}Tc-DISIDA$ scanning in the early evaluation of neonatal cholestasis and to verify the diagnostic value of this test in the differential diagnosis of biliary atresia. Methods : DISIDA scannings were performed and analyzed in 87 children(58 males and 29 females; age, 18-139 days, mean, 59.1 days) with neonatal cholestasis. Five groups according to the final diagnosis and the results of DISIDA scanning were analyzed by scatter plots using the parameters of age and the level of liver function tests(direct bilirubin, AST, ALT, ALP, GGT). The diagnostic sensitivity, specificity and accuracy of DISIDA scanning in the diagnosis of biliary atresia were compared between a higher bilirubin group and a lower bilirubin group(direct bilirubin level >5 mg/dL vs. <5 mg/dL) decided by the pattern of scatter plots. Results : DISIDA scannings in the diagnosis of biliary atresia were analyzed by high sensitivity(100 percent, 16/16) but lower specificity(70.4 percent, 50/71) and accuracy(75.9 percent, 66/87). False positivity(29.6 percent, 21/71) was higher in patients with a higher direct bilirubin level(42.5 percent for >5 mg/dL vs. 9.7 percent for <5 mg/dL, P<0.01). The age and the level of liver function tests(AST, ALT, ALP, GGT) analyzed by scatter plots revealed neither diagnostic value in predicting final diagnosis nor estimated the accuracy rate of DISIDA scanning in the evaluation of neonatal cholestasis. Conclusion : We suggest that DISIDA scannings should not be routinely used in evaluating neonatal cholestasis with elevated direct bilirubin level(>5 mg/dL), especially if it delays early diagnosis and surgical intervention.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.5 no.2
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• pp.143-149
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• 2002

Purpose: The following study was performed to reveal the relationship between Clostridium difficile colitis in childhood and associated antibiotics. Methods: From January 2000 to June 2002 at Seoul National University Children's Hospital, 85 symptomatic pediatric patients who showed positive stool culture for Clostridium difficile were included. The implicated antibiotics within 2 months before stool culture were analyzed. Of the 85 patients, there were 50 males and 35 females, and their average age was 2.5 years. Results: There was a history of implicated antibiotics within 2 months in 55 cases (67%). Forty-three patients (78%) of them showed Clostridium difficile in stool culture during antibiotics treatment. The time interval between the initiation of antibiotics and stool culture ranged from one day to 7 weeks (mean 10 days) in these patients. In the remaining 12 patients, Clostridium difficile was detected after the discontinuation of antibiotics. The time interval between the discontinuation and stool culture ranged from one day to 7 weeks (mean 12 days). The associated antibiotics were cefotaxime (20 cases), amikacin(15 cases), ampicillin (13 cases), cefazolin (8 cases), vancomycin (8 cases), etc. In 31 cases, more than one antibiotics were prescribed. Conclusion: When diarrhea occurred in young children during antibiotic usage or with a past history of recent antibiotic usage, Clostridium difficile should be investigated as a cause of diarrhea for proper management.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.5 no.2
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• pp.150-157
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• 2002

Purpose: As the incidence of non-typhoidal salmonella strains resistant to antibiotics has been increased, we attempted to investigate clinical aspects of non-typhoidal salmonella gastroenteritis and antibiotics resistance. Methods: From January 2000 to June 2002, 99 children with positive stool culture of non-typhoidal salmonella were studied about clinical features, the incidence of antibiotics and multi-drug resistance and the difference of incidence of antibiotics resistance according to immune status. Results: There were 66 males and 33 females. The majority of them were under 5 years of age (71%). 25 children were immunocompromised due to chemotherapy, steroid or immunosuppressive treatment. Serogroup D was the most common isolates (65%) followed by B (16%), C (8%) and E (8%). Resistance rate of 30% to ampicillin, 12% to chloramphenicol, 20% to trimethoprim-sulfamethoxazole (TMP-SMX), 11% to cefotaxime and 8% to cefixime were obtained. All isolates were susceptible to ciprofloxacine. Resistance rate to cefotaxime and cefixime in immunocompromised patients was 24% and 14.3% respectively, which were significantly higher compared to that in immunocompetent patients (6.8%, 5.6%, p<0.05). 11 isolates were resistant to three or more antibiotics. The incidence of multi-drug resistant isolates was significantly higher in immunocompromised patients (24%) than that of immunocompetent patients (6.8%). Conclusion: Because of the high prevalence of non-typhoidal salmonella strains resistant to ampicillin, chloramphenicol and TMP-SMX, third-generation cephalosporin might be the treatment of choice in non-typhoidal salmonella gastroenteritis. In particular, antibiotics should be carefully selected in immunocompromised patients because non-typhoidal salmonellas from them showed the higher incidence of antibiotic resistance and multi-drug resistance.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.80-86
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• 2009

Purpose : This study was performed to determine the clinical course of BCG lymphadenitis. Methods : Between May 2005 and April 2009, the medical records of 33 patients with BCG lymphadenitis were retrospectively reviewed. If needed, needle aspiration was recommended without surgical resection or antituberculous medication. Results : Of the 33 patients who were identified, 21 were males and 12 were females. Among the 33 patients, 32 were full-term babies. The mean age was 6 months (range, 2-35 months) and the most prevalent site of the lesion was the left axilla. BCG lymphadenitis was observed 1-34 months after BCG vaccination, mostly 1-6 months after vaccination. The size of the enlargement was generally 1-3 cm. The strains were identified as French (n=14), Danish (n=7), and Tokyo (n=12). BCG lymphadenitis regressed spontaneously in 19 patients. After 1-5 needle aspirations, 14 patients recovered completely. Complete regression of lymphadenitis was recorded over an average period of 4 months. Conclusion : Clinicians need to be aware of the clinical features of BCG lymphadenitis. For management of BCG lymphadenitis, regular follow-up with observation should be the mainstay. Needle aspiration is a safe and easy treatment for suppurative BCG lymphadenitis.