1.Wall Shear Stress and Flow Patterns in Unruptured and Ruptured Anterior Communicating Artery Aneurysms Using Computational Fluid Dynamics
Ui Yun LEE ; Jinmu JUNG ; Hyo Sung KWAK ; Dong Hwan LEE ; Gyung Ho CHUNG ; Jung Soo PARK ; Eun Jeong KOH
Journal of Korean Neurosurgical Society 2018;61(6):689-699
OBJECTIVE: The goal of this study was to compare several parameters, including wall shear stress (WSS) and flow pattern, between unruptured and ruptured anterior communicating artery (ACoA) aneurysms using patient-specific aneurysm geometry.METHODS: In total, 18 unruptured and 24 ruptured aneurysms were analyzed using computational fluid dynamics (CFD) models. Minimal, average, and maximal wall shear stress were calculated based on CFD simulations. Aneurysm height, ostium diameter, aspect ratio, and area of aneurysm were measured. Aneurysms were classified according to flow complexity (simple or complex) and inflow jet (concentrated or diffused). Statistical analyses were performed to ascertain differences between the aneurysm groups.RESULTS: Average wall shear stress of the ruptured group was greater than that of the unruptured group (9.42% for aneurysm and 10.38% for ostium). The average area of ruptured aneurysms was 31.22% larger than unruptured aneurysms. Simple flow was observed in 14 of 18 (78%) unruptured aneurysms, while all ruptured aneurysms had complex flow (p < 0.001). Ruptured aneurysms were more likely to have a concentrated inflow jet (63%), while unruptured aneurysms predominantly had a diffused inflow jet (83%, p=0.004).CONCLUSION: Ruptured aneurysms tended to have a larger geometric size and greater WSS compared to unruptured aneurysms, but the difference was not statistically significant. Flow complexity and inflow jet were significantly different between unruptured and ruptured ACoA aneurysms.
Aneurysm
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Aneurysm, Ruptured
;
Arteries
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Hydrodynamics
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Intracranial Aneurysm
2.Patient-Specific Computational Fluid Dynamics in Ruptured Posterior Communicating Aneurysms Using Measured Non-Newtonian Viscosity : A Preliminary Study
Ui Yun LEE ; Jinmu JUNG ; Hyo Sung KWAK ; Dong Hwan LEE ; Gyung Ho CHUNG ; Jung Soo PARK ; Eun Jeong KOH
Journal of Korean Neurosurgical Society 2019;62(2):183-192
OBJECTIVE: The objective of this study was to analyze patient-specific blood flow in ruptured aneurysms using obtained non-Newtonian viscosity and to observe associated hemodynamic features and morphological effects.METHODS: Five patients with acute subarachnoid hemorrhage caused by ruptured posterior communicating artery aneurysms were included in the study. Patients’ blood samples were measured immediately after enrollment. Computational fluid dynamics (CFD) was conducted to evaluate viscosity distributions and wall shear stress (WSS) distributions using a patient-specific geometric model and shear-thinning viscosity properties.RESULTS: Substantial viscosity change was found at the dome of the aneurysms studied when applying non-Newtonian blood viscosity measured at peak-systole and end-diastole. The maximal WSS of the non-Newtonian model on an aneurysm at peaksystole was approximately 16% lower compared to Newtonian fluid, and most of the hemodynamic features of Newtonian flow at the aneurysms were higher, except for minimal WSS value. However, the differences between the Newtonian and non-Newtonian flow were not statistically significant. Rupture point of an aneurysm showed low WSS regardless of Newtonian or non-Newtonian CFD analyses.CONCLUSION: By using measured non-Newtonian viscosity and geometry on patient-specific CFD analysis, morphologic differences in hemodynamic features, such as changes in whole blood viscosity and WSS, were observed. Therefore, measured non-Newtonian viscosity might be possibly useful to obtain patient-specific hemodynamic and morphologic result.
Aneurysm
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Aneurysm, Ruptured
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Blood Viscosity
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Hemodynamics
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Humans
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Hydrodynamics
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Intracranial Aneurysm
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Rupture
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Subarachnoid Hemorrhage
;
Viscosity
3.Acute Pseudogout of the Neck: "Crowned Dens" Revisited.
Hyesun LEE ; Hyeon Su KIM ; Ui Hong JUNG ; Hyun Hee KWON ; Young Hwan LEE ; Sung Hoon PARK
Journal of Rheumatic Diseases 2016;23(2):122-124
Calcium pyrophosphate dihydrate crystal deposition disease is associated with an acute mono- or pauciarthritis, termed "pseudogout" in elderly patients, involving a large joint (including the knees, ankles) or a chronic arthropathy manifesting as mild joint pain and stiffness. Pseudogout is a crystal-deposition disease of peripheral joints, usually encountered in elderly patients. However, acute presentation of pseudogout around the odontoid process comprises a "crowned-dens" appearance, and requires contemplation of differential diagnoses. We recently experienced a case of pseudogout in the cervical spine presenting with fever and acute neck pain that was successfully treated with a colchicine and low-dose oral steroid. We reported this case with a review of the relevant literature.
Aged
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Arthralgia
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Calcium Pyrophosphate
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Chondrocalcinosis*
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Colchicine
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Diagnosis, Differential
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Fever
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Humans
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Joints
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Knee
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Neck Pain
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Neck*
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Odontoid Process
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Spine
4.Comparison of antigenic mutation during egg and cell passage cultivation of H3N2 influenza virus
Yong Wook PARK ; Yun Hee KIM ; Hwan Ui JUNG ; Oh Seok JEONG ; Eun Ji HONG ; Hun KIM ; Jae Il LEE
Clinical and Experimental Vaccine Research 2020;9(1):56-63
Amino Acid Sequence
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Animals
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Cell Culture Techniques
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Cell Line
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Chickens
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Eggs
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Erythrocytes
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Guinea Pigs
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Hand
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Hemagglutination
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Hemagglutinins
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Humans
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Influenza Vaccines
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Influenza, Human
;
Neuraminidase
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Orthomyxoviridae
;
Ovum
;
Sequence Analysis
;
Specific Pathogen-Free Organisms
5.Neutrophil to Lymphocyte Ratio: A Predictive Marker for Treatment Outcomes in Patients With Rectal Cancer Who Underwent Neoadjuvant Chemoradiation Followed by Surgery
Byong Ho JEON ; Ui Sup SHIN ; Sun Mi MOON ; Jung Il CHOI ; Mi Sook KIM ; Kie Hwan KIM ; Se Jin SUNG
Annals of Coloproctology 2019;35(2):100-106
PURPOSE: In this study, we investigated the role of neutrophil to lymphocyte ratio (NLR) as a predictor of tumor response and as a prognostic factor in patients with rectal cancer who had undergone curative surgery after neoadjuvant chemoradiation therapy (nCRT). METHODS: Between January 2009 and July 2016, we collected 140 consecutive patients who had undergone curative intent surgery after nCRT due to rectal adenocarcinoma. We obtained the pre- and post-nCRT NLR by dividing the neutrophil count by the lymphocyte count. The cutoff value was obtained using receiver operating characteristic analysis for tumor response and using maximally selected rank analysis for recurrence-free survival (RFS). The relationship among NLR, tumor response, and RFS was assessed by adjusting the possible clinico-pathological confounding factors. RESULTS: The possibility of pathologic complete response (pCR) was significantly decreased in high pre- (>2.77) and postnCRT NLR (>3.23) in univariate regression analysis. In multivariate analysis, high post-nCRT NLR was an independent negative predictive factor for pCR (adjusted odds ratio, 0.365; 95% confidence interval [CI], 0.145–0.918). The 5-year RFS of all patients was 74.6% during the median 37 months of follow-up. Patients with higher pre- (>2.66) and post-nCRT NLR (>5.21) showed lower 5-year RFS rates (53.1 vs. 83.3%, P = 0.006) (69.2 vs. 75.7%, P = 0.054). In multivariate Cox analysis, high pre-nCRT NLR was an independent poor prognostic factor for RFS (adjusted hazard ratio, 2.300; 95% CI, 1.061–4.985). CONCLUSION: Elevated NLR was a negative predictive marker for pCR and was independently associated with decreased RFS. For confirmation, a large-scale study with appropriate controls is needed.
Adenocarcinoma
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Biomarkers
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Chemoradiotherapy
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Follow-Up Studies
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Humans
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Lymphocyte Count
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Lymphocytes
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Multivariate Analysis
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Neutrophils
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Odds Ratio
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Polymerase Chain Reaction
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Prognosis
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Rectal Neoplasms
;
ROC Curve
6.Association between Obesity and Physical Fitness, and Hemoglobin A1c Level and Metabolic Syndrome in Korean Adults.
Yoonsuk JEKAL ; Mi Kyung LEE ; Sukyung PARK ; Seung Hwan LEE ; Jun Young KIM ; Jung Ui KANG ; Masayo NARUSE ; Sang Hwan KIM ; Sun Hyeon KIM ; Sang Hui CHU ; Sang Hoon SUH ; Justin Y JEON
Korean Diabetes Journal 2010;34(3):182-190
BACKGROUND: The purpose of the current study was to investigate the association of obesity level, physical fitness level, hemoglobin A1c (HbA1c) level and metabolic syndrome (MetS) risk factors among Korean adults. METHODS: A total of 557 adults (272 males and 285 females) who underwent medical check-up at local hospital were recruited. In addition to regular health check-up, cardiopulmonary fitness, muscular endurance were measured and their association were analyzed. RESULTS: The prevalence of MetS was 31.7% for males and 23.7% for females. Females with the higher muscular endurance had lower waist circumference, triglyceride level, and HbA1c level than those with the lower muscular endurance. Males with the higher level of cardiopulmonary fitness had lower diastolic blood pressure, lower high-sensitivity C-reactive protein level and higher high density lipoprotein cholesterol level than males with the lower level of cardiopulmonary fitness. Females with the higher level of cardiopulmonary fitness had lower body weight, body mass index, systolic blood pressure, and fasting blood glucose level than females with the lower level of cardiopulmonary fitness. Participants with the higher level of adiposity and the lower level of physical fitness were 5.26 times (95% confidence interval [CI], 2.19 to 12.62), 5.71 times (95% CI, 2.23 to 14.60) more likely to have MetS, respectively, in male and female compared to participants who were neither obese nor have the lower level of fitness. CONCLUSION: This study suggests that maintaining a healthy body weight as well as a certain level of fitness is important for the prevention of MetS.
Adiposity
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Adult
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Blood Glucose
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Blood Pressure
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Body Mass Index
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Body Weight
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C-Reactive Protein
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Cholesterol
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Cholesterol, HDL
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Fasting
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Female
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Hemoglobins
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Humans
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Hypotension
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Lipoproteins
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Male
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Obesity
;
Physical Fitness
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Prevalence
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Risk Factors
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Waist Circumference
7.Erratum: Author's Name Correction.
Yoonsuk JEKAL ; Mi Kyung LEE ; Sukyung PARK ; Seung Hwan LEE ; Jun Young KIM ; Jung Ui KANG ; Masayo NARUSE ; Sang Hwan KIM ; Sun Hyun KIM ; Sang Hui CHU ; Sang Hoon SUH ; Justin Y JEON
Korean Diabetes Journal 2010;34(4):265-265
No abstract available.
8.Neuroendocrine Effects in Occupational Solvents Exposure.
Chae Un LEE ; Jong Tae LEE ; Ui Wha CHUNG ; Hae Suk SOHN ; Deog Hwan MOON ; Jin Ho CHUN ; Jung Hak KANG ; Chang Hee LEE ; Hwi Dong KIM ; Jong Ham KIM ; Kui Oak JUNG
Korean Journal of Occupational and Environmental Medicine 1995;7(2):362-374
Long term occupational exposure to solvent mixtures may cause adverse effects to the central nervous system with neurobehavioral symptoms. And some organic solvents have been suggested to cause impairment of tuberoinfundibular dopaminergic activity and neurochemical mechanisms controlling pituitary secretion. For the purpose of assessing neuroendocrine effects in occupational solvents exposure, hormonal study settings (shoes-manufacturing industry & fishing products industry) and compared with nonexposed controls (33men, 85women). Male workers exposed to solvent mixtures had significantly lower plasma level of follicle-stimulating hormone (FSH) than nonexposed male controls. While female workers exposed to solvent mixtures had significantly lower plasma levels of growth hormone (GH), and thyroid-stimulating hormone (TSH) than nonexposed female controls. The results of significant decrease in plasma concentrations of pituitary hormones (FSH, GH, and TSH) in workers exposed solvent mixtures indicate that occupational exposure to solvent mixtures may induce neuroendocrine effects through an effect on hypothalamic pituitary axis.
Axis
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Central Nervous System
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Female
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Follicle Stimulating Hormone
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Growth Hormone
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Humans
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Male
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Occupational Exposure
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Pituitary Hormones
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Plasma
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Solvents*
;
Thyrotropin
9.Study on Absorbed Dose Determination of Electron Beam Quality for Cross-calibration with Plane-parallel Ionization Chamber.
Jeong Eun RAH ; Dong Oh SHIN ; So Hyun PARK ; Hojin JEONG ; Ui Jung HWANG ; Sung Hwan AHN ; Young Kyung LIM ; Dong Wook KIM ; Myonggeun YOON ; Dong Ho SHIN ; Se Byeong LEE ; Tae Suk SUH ; Sung Yong PARK
Korean Journal of Medical Physics 2009;20(2):97-105
Absorbed dose to water based protocols recommended that plane-parallel chambers be calibrated against calibrated cylindrical chambers in a high energy electron beam with R50>7 g/cm2 (E> or =16 MeV). However, such high-energy electron beams are not available at all radiotherapy centers. In this study, we are compared the absorbed dose to water determined according to cross-calibration method in a high energy electron beam of 16 MeV and in electron beam energies of 12 MeV below the cross-calibration quality remark. Absorbed dose were performed for PTW 30013, Wellhofer FC65G Farmer type cylindrical chamber and for PTW 34001, Wellhofer PPC40 Roos type plane-parallel chamber. The cylindrical and the plane-parallel chamber to be calibrated are compared by alternately positioning each at reference depth, zref=0.6R50-0.1 in water phantom. The DW of plane-parallel chamber are derived using across-calibration method at high-energy electron beams of 16, 20 MeV. Then a good agreement is obtained the DW of plane-parallel chamber in 12 MeV. The agreement between 20 MeV and 12 MeV are within 0.2% for IAEA TRS-398.
Electrons
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Water
10.Dosimetry by Using EBT2 Film for Total Skin Electron Beam Therapy (TSET).
Ui Jung HWANG ; Jeong Eun RAH ; Hojin JEONG ; Sung Hwan AHN ; Dong Wook KIM ; Sang Yeob LEE ; Young Gyung LIM ; Myonggeun YOON ; Dong Ho SHIN ; Se Byeong LEE ; Sung Young PARK ; Hong Ryull PYO ; Weon Kuu CHUNG
Korean Journal of Medical Physics 2010;21(1):60-69
For treatment of Total Skin Electron beam Therapy (TSET), measurement of dose at various conditions is need on the contrary to usual radiotherapy. When treating TSET with modified Stanford technique based on linear accelerator, the energy of treatment electron beam, the spatial dose distribution and the actual doses deposited on the surface of the patient were measured by using EBT2. The measured energy of the electron beam was agreed with the value that measured by ionization chamber, and the spatial dose distribution at the patient position and the doses at several point on the patient's skin could be easily measured by EBT2 film. The dose on the patient that was measured by EBT2 film showed good agreement with the data measured simultaneously by TLD. With the results of this study, it was proven that the EBT2 film can be one of the useful dosimeter for TSET.
Electrons
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Humans
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Particle Accelerators
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Skin