• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.1-13
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• 2018

Divers types of Personal Mobility(PM) are appeared on the market after the Segway is introduced. PMs have propagated very rapidly with their ease of use, and accidents related with PM show a sudden increase. Many studies on the PM are performed as its trend, but dring safety of passengers are excluded. In this study, criteria which can be adopted for PM's driving safety evaluation are reviewed. Also result of driving safety evaluation on 3 types of PM(wheel chair, kickboard, scooter(seating/standing) and walking using deducted criteria is given. COG(Center of the gravity) and SM(Stability Metric) are finally selected two criteria among many of them used in other fields. COG indicates how the center of mass deviates from the direction of the gravity. SM is a normalized value of generated force when PM moves as internal force, angular momentum, and ground reaction force. 0 means stop, and negative value means rollover, so it can be used for safety evaluation of PM. Average and standard deviation of measurement are standard of safety on the COG analysis. Wheel chair is the most safe and kickboard is the most unstable on the COG analysis. Wheel chair is also ranked as top safe on the SM analysis. Among two riding types(seating and standing) on the scooter, seating type is evaluated more safer than standing type. It is proposed that more various type of PMs are need to get safety evaluation for drivers and devices themselves together.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.33-44
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• 2012

Transparent exopolymer particles (TEP) are formed by aggregation of polysaccharide products excreted by phytoplankton and have sticky character like gel. They play important role in the production of marine snow in water column. To study the distribution pattern of TEP concentration and its role in carbon cycle in the surface ocean, we measured pH, Total alkalinity (TA), and chlorophyll-a in addition to physical characteristics of seawater within the surface water column. TEP concentrations ranged from nearly undetectable values to $338{\mu}g\;Xeq\;l^{-1}$. They were considerably lower than previously reported values from costal sites, but showed similar values observed in other oceanic region during phytoplankton bloom periods. The spatial distribution of TEP concentrations were similar to those of chlorophyll-a, which indicate that the production of TEP were closely related to phytoplankton. Calculated total dissolved inorganic carbon ($TCO_2$) from the pH and TA was normalized to 35 psu of salinity ($NTCO_2$) and showed negative linear relationship with temperature. Biological drawdown of $NTCO_2$ ($NTCO_{2bio}$) was estimated from the difference between theoretical $NTCO_2$ values and observed $NTCO_2$. In the warm region located south of $40^{\circ}N$ along the $132.5^{\circ}N$ meridional lines, $NTCO_{2bio}$ showed negative value and TEP concentrations were high. This suggested that negative $NTCO_{2bio}$ may be attributed to the biological processes. At the stations located between 44 and $46^{\circ}N$, TEP concentrations showed high concentration at the chlorophyll-a maximum layer within the water column while they showed low concentration in the surface layer. Carbon content of TEP constituted about 40% of $NTCO_{2bio}$ at the chlorophylla maximum layer. In this study, we could not observe any positive and negative relationship between TEP concentration and $NTCO_2$ or pH. It is obvious that we should consider the importance of TEP in the biological carbon cycling processes within surface layer.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.130-136
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• 2008

Purpose: Lamivudine is known to be effective for the treatment of chronic hepatitis B in adults. However, data on lamivudine therapy in pediatrics is limited. The aim of this study was to evaluate the efficacy and durability of lamivudine therapy for chronic hepatitis B in Korean children. Methods: A total of 44 children (27 males and 17 females, ages 6 months to 14.8 years, mean age 6.7 years) with chronic hepatitis B who received lamivudine (3 mg/kg/day, max 100 mg) for at least 12 months were enrolled. We evaluated the serum AST, ALT and serological HBV markers (HBsAg and anti-HBs, HBeAg and anti HBe, and HBV DNA) periodically. Predictive three year cumulative seroconversion rates were obtained using the Kaplan-Meier method. Results: Twenty one (48%) of 44 children achieved seroconversion of HBeAg by three years, while 23 (42%) children did not. HBV DNA was cleared in 34 (77%) children and the serum ALT levels were normalized in 41 children (93%). The three year cumulative seroconversion rates were 60% for HBeAg, and the clearance rates were 76% for HBV DNA. Eighteen children who discontinued lamivudine after HBeAg seroconversion maintained the therapeutic response for three years (treatment duration 13~58 months mean 24 months). Viral breakthrough developed in 12 children (27%) during the therapy and the YMDD mutation was documented in 11 children (25%). The mean duration for the development of a mutation was 22.7 months. Loss of HBsAg occurred in 6 children (14%). The pretreatment ALT levels were higher in responders; however, the differences were not statistically significant (p>0.05). Conclusion: The results of this study showed that lamivudine treatment had a favorable effect and durable therapeutic response in children with chronic hepatitis B. Long term follow-up and alternative therapy are warranted for those patients who do not respond to this treatment.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.1
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• pp.58-65
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• 2010

Purpose: Since there are few studies involving acute pancreatitis in children, we reviewed our experience with this medical condition to describe the clinical features. Methods: A retrospective analysis was conducted by reviewing the medical records of 41 patients with AP who were admitted to the Department of Pediatrics of Pusan National University Hospital between January 1996 and June 2007. Results: Twenty males and 21 females (mean age, 8.7${\pm}$4.5 years) were included. In 22 patients (53.7%), no definitive causes were found. The most common etiologies were choledochal cysts (22.0%). Necrotizing pancreatitis was diagnosed in 5 patients (12.2%), and recurrent acute pancreatitis in 4 patients (9.8%). CT findings included pancreatic swelling (43.9%), peripancreatic fluid collection (29.3%), ascites (24.4%), and peripancreatic fat necrosis (12.2%). Serum amylase and lipase levels at diagnosis were 535.3${\pm}$553.2 and 766.2${\pm}$723.6 U/L, respectively, and were normalized within 1 week in 22 and 14 patients, respectively. On the basis of the Balthazar scale, 2 patients were diagnosed with severe AP. In 4 patients (9.8%), a surgical procedure was indicated. Major complications included ascites (32.3%), sepsis (16.1%), and pseudocyst and renal impairments (12.9%). Two patients died from multi-organ failure. Conclusion: The etiologies of AP in children are varied. Most children have a single episode and a self-limited course. However, AP of childhood still carries significant morbidity and mortality. Early diagnosis, appropriate treatment according to disease severity, and management of complications are important.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.61-66
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• 2010

In this paper we evaluated small field dose characteristics of exclusive cone fields versus square fields for stereotactic radiosugery (SRS) which is based on linear accelerators (LINAC). For this test, we used a small beam detector (stereotactic fields detector : SFD) with a 6 MV photon beam and a water phantom system (IBA, Germany). Percentage depth dose (PDD) was measured for different field sets (cones : ${\Phi}1\;cm$, ${\Phi}2\;cm$, ${\Phi}3\;cm$ ; square fields : $1{\times}1\;cm^2$, $2{\times}2\;cm^2$, $3{\times}3\;cm^2$) at a source skin distance (SSD) of 100 cm. We measured the point depths at 1.5 cm, 5 cm, 10 cm, 20 cm, and 30 cm. The output factors were measured under the same geometrical conditions of the PDD and normalized at the maximum dose depth. To analyze the penumbra, we measured the dose profile with 95 cm of SSD, 5 cm of depth for each field sizes (${\Phi}1\;cm$, ${\Phi}3\;cm$, $1{\times}1\;cm^2$, and $3{\times}3\;cm^2$) using SFD. We obtained the values for every 1 mm interval in the physical field (90%) and 0.5 mm interval in the penumbra region (20 to 80%). The PDD variation of exclusive cones and square fields were 4.3 to 7.9% lesser than the standard field size ($10{\times}10\;cm^2$. The variation of PDD was reduced while the field size was increased. To compare the beam quality, we analyzed the $PDD_{20,10}$ and the results showed under the 1% of variations for all experiments except for ${\Phi}1\;cm$ cone and $1{\times}1\;cm^2$ fields. Output factors of exclusive cone were increased 3.1~4.6% than the square fields, and the penumbra region of exclusive cone was reduced 20% as compared to the square fields. As the previous researches report, it is very important for SRS and SFD that precise dosimetry in small beam fields. In this paper, we showed the effectiveness of exclusive cone, compared to square field. And we will study on the various detector characteristics for small beam fields.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.242-248
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• 2006

Purpose: Neonatal hepatitis is the major cause of neonatal cholestasis and may be divided into infectious, metabolic, genetic, and idiopathic neonatal hepatitis. Non-familial, non-metabolic, and non-A, B, C viral neonatal hepatitis is known to have made satisfactory progress, but little is known about its chronic clinical features. Methods: Clinical and histological assessments were carried out in 34 cases with chronic neonatal hepatitis [elevated serum alanine aminotrasferase (ALT) level for more than 6 months] except for A, B, C viral hepatitis, metabolic, or genetic neonatal hepatitis, who were admitted to the Department of Pediatrics, Pusan National University Hospital, from January 1998 to January 2004. Results: Males were more common (70%). Jaundice (100%) and hepatomegaly (44%) were frequent manifestations. Peak serum ALT levels were most commonly below 300 IU/L in 41.2% of patients and peak serum direct bilirubin levels were most commonly between 1.0~5.0 mg/dL in 50% of patients. Ten cases (34%) of 29 patients had positive serum cytomegalovirus (CMV) IgM or urine CMV polymerase chain reaction. Serum ALT level was normalized within 1 year in 11 (37.9%) of 29 cases, and within 2 years in 9 (69.2%) of 13 cases. Serum ALT level was elevated persistently over 2 years in four (30.7%) of 13 cases. Histologic findings such as portal or periportal activity, lobular necrosis, portal or periportal fibrosis were more severe in patients with persistent ALT elevation over 2 years than in those showing normalization of ALT within 2 years (p>0.05). Conclusion: When the elevation of ALT level sustains over 1 year in non-familiar, non-metabolic, non-A, B, C viral neonatal hepatitis, an assessment of the severity of liver injury and a careful monitoring about chronic liver disease may be required.

• Journal of Korean Medical Science
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• v.33 no.49
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• pp.323.1-323.12
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• 2018

Background: Vitamin K antagonist (VKA) to prevent thromboembolism in non-valvular atrial fibrillation (NVAF) patients has limitations such as drug interaction. This study investigated the clinical characteristics of Korean patients treated with VKA for stroke prevention and assessed quality of VKA therapy and treatment satisfaction. Methods: We conducted a multicenter, prospective, non-interventional study. Patients with $CHADS_2{\geq}1$ and treated with VKA (started within the last 3 months) were enrolled from April 2013 to March 2014. Demographic and clinical features including risk factors of stroke and VKA treatment information was collected at baseline. Treatment patterns and international normalized ratio (INR) level were evaluated during follow-up. Time in therapeutic range (TTR) > 60% indicated well-controlled INR. Treatment satisfaction on the VKA use was measured by Treatment Satisfaction Questionnaire for Medication (TSQM) after 3 months of follow-up. Results: A total of 877 patients (age, 67; male, 60%) were enrolled and followed up for one year. More than half of patients (56%) had $CHADS_2{\geq}2$ and 83.6% had $CHA_2DS_2-VASc{\geq}2$. A total of 852 patients had one or more INR measurement during their follow-up period. Among those patients, 25.5% discontinued VKA treatment during follow-up. Of all patients, 626 patients (73%) had poor-controlled INR (TTR < 60%) measure. Patients' treatment satisfaction measured with TSQM was 55.6 in global satisfaction domain. Conclusion: INR was poorly controlled in Korean NVAF patients treated with VKA. VKA users also showed low treatment satisfaction.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.192-200
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• 2008

To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.113-120
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• 1987

The effect of intravesical formalin instillation as a therapeutic modality for intractable bladder hemorrhage is well known. And despite clear evidence of therapeutic efficacy of intravesical cytotoxic drugs and/or BCG immunotherapy, there have been substantial recurrences during followup after transurethral resection for superficial bladder tumor. If formalin injected at the bed of superficial bladder tumor is able to coagulate and necrotize the tumor, it will be greatly helpful to the patients With recurrent bladder tumor developed during followup. Since this technique is applicable on outpatient basis, an economical as well as a psychological burden of the patients can be reduced considerably. The purpose of this study is to evaluate the effect of submucosal formalin injection on rat bladder wall, 36 healthy adult male Sprague-Dawley rats (weighing 350gm in average) were divided into 3 groups: In Group I (control group), 0.01ml of normal saline was injected submucosally at the left posterolateral wall of the bladder opened under intraperitoneal Nembutal anesthesia ; In Group II and III, 0.01 ml of 10% and 4% formalin, respectively, were administered at the same site as in the Group I, two rats in each group were sacrificed at day 1, 2, and 3, and week 1, 2 and 4 after injection, respectively. Gross and microscopic examination of the cystectomized specimen were done in each group. In the Group II, bladder stones were formed at week I, and in both the Group I and III, stones were seen at week 2 post injection. There was no significant difference III histologic findings of the bladder between the group II and III. Mucosal ulcer and/or prominent mucosal disruption was observed at 24 hours after injection in both Group II and III. Epithelial regeneration began at day 2, and was marked at day 3, and epithelial lining was almost normalized one week after injection. Subepithelial edema, telangiectasia and inflammatory reaction were prominent at 24 hours post formalin injection. Subepithelial edema persisted in moderate degree for 1 week. Telangiectasia and inflammatory reaction were noted for 4 weeks. Mild degree of these findings also appeared In the control group. Fibroblastic proliferation appeared at day 2 and persisted in moderate degree for 4 weeks. There has been no mortality or bladder perforation. These results suggest that clinical application of this technique is feasible for the selected cases of recurrent, solitary superficial bladder tumor. However, optimal dosage of formalin in relation to the size of the lesion remains to be investigated.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.136-141
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• 2001

Purpose : To evaluate the significance of serum SCC for the monitoring of treatment response and the early detection of distant metastasis during radiotherapy (RT). Materials and Methods : In 13 patients with histologically proven primary squamous cell carcinoma of uterine cervix, serum SCC values were checked in pre-RT point, weekly during RT, and in post-RT point. Results : In 4 of 13 cases, metastasis appeared at the end of external RT, so that intracavitary radiation couldn't be peformed.01 these 4 cases,3 with elevated pre-RT SCC level, who resulted in lung metastasis on chest PA at the end of external RT showed decreased post-RT SCC value despite of metastasis. Of all 10 cases with elevated pre-RT SCC value (including 3 with metastasis at the end of external RT), SCC value was higher than pre-RT value in 7 at 9 Gy and the difference was statistically significant. At 18 Gy, SCC was higher in 4 and lower in 6 than pre-RT value. After 18 Gy, SCC value decreased continuously to the end of RT in all 10 cases. Conclusion : During RT, SCC value increased initially at 9 Gy. To 18 Gy, SCC value decreased to the nearly same with pre-RT value. After 18 Gy, to the end of RT, SCC value decreased continuously and normalized in completely responded cases. In cases with appearance of lung metastasis, SCC value also decreased with the disappearance of main mass of uterine cervix despite metastasis.