A new gas – solid reaction model for voloxidation process with spallation

류제일,우승민 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.1

A new methodology, the crackespallation model, has been developed to analyze gasesolid reactionsdominated by crack growth inside of the solid reactant and spallation phenomena. The new modelphysically represents three processes of the reaction progress: (1) diffusion of gas reactant throughpores; (2) growth of product particle in pores; and (3) crack and spallation of solid reactant. The validationof this method has been conducted by comparison of results obtained in an experiment foroxidation of UO2 and the shrinking core model. The reaction progress evaluated by the crackespallationmodel shows better agreement with the experimental data than that evaluated by the shrinking coremodel. To understand the trigger point during the reaction progress, a detailed analysis has been conducted. A parametric study also has been performed to determine mass diffusivities of the gas reactantand volume increase constants of the product particles. This method can be appropriately applied to thegasesolid reaction based on the crack and spallation phenomena such as the voloxidation process.

지연성 외상성 뇌실질내 출혈 환자의 치료를 결정하는 임상적, 영상학적 예후인자에 대한 평가

류제일 ( Je Il Ryu ),김충현 ( Choong Hyun Kim ),김재민 ( Jae Min Kim ),정진환 ( Jin Hwan Cheong ) 대한외상학회 2015 大韓外傷學會誌 Vol.28 No.4

Purpose: Delayed, traumatic, intraparenchymal hemorrhage (DTIPH) is a well-known contributing factor to secondary brain damage that evokes severe brain edema and intracranial hypertension. Once it has occurred, it adversely affects the patient’s outcome. The aim of this study was to evaluate the prognosis factors for DTIPH by comparing clinical, radiological and hematologic results between two groups of patients according to whether surgical treatment was given or not. Methods: The author investigated 26 patients who suffered DTIPH during the recent consecutive five-year period. The 26 patients were divided according to their having undergone either a decompressive craniectomy (n=20) or continuous conservative treatment (n=6). A retrospective investigation was done by reviewing their admission records and radiological findings. Results: This incidence of DTIPH was 6.6% among the total number of patients admitted with head injuries. The clinical outcome of DTIPH was favorable in 9 of the 26 patients (34.6%) whereas it was unfavorable in 17 patients (65.4%). The patients with coagulopathy had an unexceptionally high rate of mortality. Among the variables, whether the patient had undergone a decompressive craniectomy, the patient’s preoperative clinical status, and the degree of midline shift had significant correlations with the ultimate outcome. Conclusion: In patients with DTIPH, proper evaluation of preoperative clinical grading and radiological findings can hamper deleterious secondary events because it can lead to a swift and proper decompressive craniectomy to reduce the intracranial pressure. Surgical decompression should be carefully selected, paying attention to the patient’s accom-panying injury and hematology results, especially thrombocytopenia, in order to improve the patient’s neurologic outcomes. [ J Trauma Inj 2015; 28: 223-231 ]

Reconsideration of Significant Quantity (SQ) for Pu Based on the Strategic Impact Investigation of Non-Strategic Nuclear Weapon (NSNW) Using Monte-Carlo Simulations

우승민,이만석,류제일 한국방사성폐기물학회 2021 방사성폐기물학회지 Vol.19 No.4

The present multidisciplinary study, which is a nexus of engineering and political science, investigates how the modernization of Non-Strategic Nuclear Weapons (NSNWs) affects the IAEA safeguards system based on the likelihood of the use of nuclear weapons. To this end, this study examines the characteristics of modernized NSNWs using Monte Carlo techniques. The results thus obtained show that 10 kt NSNWs with a Circular Error Probability (CEP) of 10 m can destroy the target as effectively as a 500 kt weapon with a CEP of 100 m. The IAEA safeguards system shows that the Significant Quantity (SQ) of 1 of plutonium is 8 kg, a parameter that was established when strategic nuclear weapons were dominant. However, the results of this study indicate that in recent years, low-yield nuclear weapons such as NSNWs have been more strategically interesting than strategic nuclear weapons as NSNWs require less plutonium than strategic nuclear weapons. Therefore, we would like to conclude that reducing the SQ of plutonium can result in more robust safeguards and non-proliferation strategies.

Retrograde Stent-assisted Coil Embolization of Wide-neck or Branch-incorporated Posterior Communicating Artery Aneurysm

박정우,정진환,최규선,박동우,류제일,김재민,김충현 대한뇌혈관외과학회 2016 Journal of Cerebrovascular and Endovascular Neuros Vol.18 No.2

Endovascular coil embolization using a balloon- or stent-assisted technique for the treatment of wide-necked posterior communicating artery (PcomA) aneurysms is well established. However, complete aneurysm occlusion with preservation of the PcomA can be difficult in case of wide-neck aneurysms with a PcomA incorporation. We present two cases of stent-assisted coil embolization using a retrograde approach through the posterior circulation for wide-neck or branch-incorporated PcomA aneurysms. Retrograde stenting was successful without periprocedural complications. These aneurysms were completely occluded. The patency of the PcomA was maintained in all cases.

Postpartum Superior Sagittal Sinus Thrombosis: A Case Report

Kun Hee Han,Yu Deok Won,한명훈,류제일,Jae Min Kim,김충현,Jin Hwan Cheong 대한신경손상학회 2018 Korean Journal of Neurotrauma Vol.14 No.2

Cerebral venous sinus thrombosis (CVST) is a rare disease. Early diagnosis and treatment are important, as CVST is potentially fatal. Pregnancy and puerperium are known risk factors for CVST. Here, we report the case of a patient who developed superior sagittal sinus thrombosis after a normal vaginal delivery. A 20-year-old woman presented with a headache and seizures two days after a normal vaginal delivery. Initially, brain computed tomography (CT) showed asubarachnoid hemorrhage in the right parietal lobe and sylvian fssure, together with mild cerebral edema. CT angiography revealed superior sagittal sinus thrombosis. Multiple micro-infarctions were seen on diffusion-weighted magneticresonance images. An intravenous infusion of heparin and mannitol was administered immediately. Two days after treatment initiation, the patient showed sudden neurological deterioration, with left-sided hemiplegia. Brain CT showed moderate brain edema and hemorrhagic densities. Emergency decompressive craniectomy was performed, and heparin wasre-administered on post-operative day (POD) 1. On POD 9, the patient’s mental state improved from stupor to drowsy, butthe left-sided hemiplegia persisted. CT angiography showed that the superior sinus thrombosis had decreased. Superiorsagittal sinus thrombosis is an uncommon complication, with an unfavorable outcome, after delivery. Timely diagnosisand treatment are important for preventing neurological deterioration.

Chemoradiotherapy Alters Protein Expression in Glioblastoma Multiforme

황미나,박현희,한명훈,최호진,이규용,이영주,김재민,정진환,류제일,고용,고성호 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.4

LGR5 and Downstream Intracellular Signaling Proteins Play Critical Roles in the Cell Proliferation of Neuroblastoma, Meningioma and Pituitary Adenoma

황민아,한명훈,박현희,최호진,이규용,이영주,김재민,정진환,류제일,민경환,오영하,고용,고성호 한국뇌신경과학회 2019 Experimental Neurobiology Vol.28 No.5

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has been reported to play critical roles in the proliferation of various cancer cells. However, the roles of LGR5 in brain tumors and the specific intracellular signaling proteins directly associated with it remain unknown. Expression of LGR5 was first measured in normal brain tissue, meningioma, and pituitary adenoma of humans. To identify the downstream signaling pathways of LGR5, siRNA-mediated knockdown of LGR5 was performed in SH-SY5Y neuroblastoma cells followed by proteomics analysis with 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In addition, the expression of LGR5-associated proteins was evaluated in LGR5-inhibited neuroblastoma cells and in human normal brain, meningioma, and pituitary adenoma tissue. Proteomics analysis showed 12 protein spots were significantly different in expression level (more than two-fold change) and subsequently identified by peptide mass fingerprinting. A protein association network was constructed from the 12 identified proteins altered by LGR5 knockdown. Direct and indirect interactions were identified among the 12 proteins. HSP 90-beta was one of the proteins whose expression was altered by LGR5 knockdown. Likewise, we observed decreased expression of proteins in the hnRNP subfamily following LGR5 knockdown. In addition, we have for the first time identified significantly higher hnRNP family expression in meningioma and pituitary adenoma compared to normal brain tissue. Taken together, LGR5 and its downstream signaling play critical roles in neuroblastoma and brain tumors such as meningioma and pituitary adenoma.