• Tunnel and Underground Space
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• v.33 no.1
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• pp.57-69
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• 2023

In this study, we simulated induced seismicity in the Groningen natural gas reservoir using 2D hydro-mechanical coupled discrete element modelling (DEM). The code used is PFC2D (Particle Flow Code 2D), a commercial software developed by Itasca, and in order to apply to this study we further developed 1)initialization of inhomogeneous reservoir pressure distribution, 2)a non-linear pressure-time history boundary condition, 3)local stress field monitoring logic. We generated a 2D reservoir model with a size of 40 × 50 km² and a complex fault system, and simulated years of pressure depletion with a time range between 1960 and 2020. We simulated fault system failure induced by pressure depletion and reproduced the spatiotemporal distribution of induced seismicity and assessed its failure mechanism. Also, we estimated the ground subsidence distribution and confirmed its similarity to the field measurements in the Groningen region. Through this study, we confirm the feasibility of the presented 2D hydro-mechanical coupled DEM in simulating the deformation of a complex fault system by hydro-mechanical coupled processes.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.245-261
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• 1997

Slipped capital femoral epiphysis(SCFE) is a disorder in which there is a gradual or acute disruption through the capital physeal plate. The physiolysis is through a widened zone of hypertrophy, which is weakened due to altered chondrocytic maturation and endochondral ossification. The cause or causes of SCFE remain uncertain. The association of obesity and adolescent age with growth rate are predisposing factors. The possibility that most patients with subclinical hormonal abnormality were proved. The goal of treatment of slipped capital femoral epiphysis is to restore the function of the hip and delay the development of degenerative osteoarthrosis by prevention of additional displacement of the epiphysis. We report 10 patients(12hips) with SCFE who were treated by surgical means and followed along for more than one year, at Yeungnam University Hospital, from 1989 to 1996. There were six boys and four girls. The average age at operation was 11.8 years. Seven cases occurred in the left hip, one case in the right and 2 cases had bilateral involvement, five cases had a history of minor trauma on affected hip. Among hormonally studied six patients, panhypopituitarism patient was one case; decreased testosterone, two; decreased growth hormone, two; and decreased thyroid hormone, one. According to clinical stage, two cases were the acute type; five cases, acute on chronic type; and three cases, chronic type. On the radiological grades of slipping, mild slippage were nine hips; moderate, one; and severe, two. The eleven hips were treated by pin fixation in situ, and one, by cuneiform osteotomy. On the average follow-up of 2.6 years, ten hips were excellent or good functional results, two hips were failure.

• Tuberculosis and Respiratory Diseases
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• v.41 no.5
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• pp.568-573
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• 1994

Corticosteroids are widely used in the treatment of various diseases because of its potent antiinflammatory effect. According to recent knowledge, bronchial asthma is also chronic inflammatory disease. Therefore antiinflammtory agent such as cromoyln sodium and corticosteroid is highly recommended for treament of chronic bronchial asthma. Especially hydrocortisone succinate (Solu-Cortef) is commonly used for treament to acute asthmatic attack via intravenous injection due to have rapid therapeutic onset and short duration. Since Sunaga et al. reported acute asthma attack after hydrocortisone injection in 1973, several cases of bronchospam with or without angioedema and urticaria after intravenous injection of hydrocortisone have been reported. We experienced a case of severe bronchospasm and acute respiratory failure after intraveous injection of hydrocortisone succinate in 64 year-old female asthmatic patient who visited to emergency room for acute asthmatic attack. About 5 minites after Solu-Cortef injection, a severe bronchospasm with arterial hypoxemia was developed. In order to confirm the suspected relationship between the offending drug(Solu-Cortef) and acute bronchospasm, we examed intravenous and inhalation provocation test by hydrocortisone succinate and methylprednisolone(control). After administration of hydrocortisone succinate via intravenous and inhalation route, severe asthmatic attack occurred. But administration of intravenous methylprednisolone and orall triamcinolone and saline were not provoke bronchospasm. Skin test using hydrocortisone sodium succinate was also positive. Administration of hydrocortisone is very serious to asthmatic patient with hydrocortisone hypersensitivity. Therefore, the clinician must be have history taking about previous adverse reaction of steroid before its clinical use. And methylprednisone may be useful and safe drug to the treatment of acute asthmatic patient with hydrocortisone hypersensitivity.

• Sleep Medicine and Psychophysiology
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• v.14 no.1
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• pp.49-53
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• 2007

Mitochondrial myopathy is characterized by variable clinical manifestations from mild limb weakness to fatal respiratory failure and central nervous system sequela. But it is a rare event that sleep disordered breathing become a clue of diagnosis for mitochondrial myopathy. We report a case of a 21 year-old man who was diagnosed as mitochondrial myopathy during the investigation for the possible cause of chronic hypoventilation syndrome. Before being admitted to our hospital, he was suspected as having sleep apnea syndrome in another hospital. We re-evaluated the history, physical examination, laboratoy findings and polysomnography in detail. Severe hypoxemia was noted during REM sleep on nocturnal polysomnography and the diagnosis of mitochondrial myopathy was made by muscle biopsy in rectus abdominis muscle. We treated him with bilevel positive airway pressure therapy during sleep and it could reverse the hypoxemia during REM sleep. He could be discharged with improved condition and is being well with the use of this ventilatory assistance.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.14-21
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• 1996

Objectives: Although outbreak of MDR Tb has been a recent problem in western countries, it has been a longstanding problem in Korea. The poor outcome of MDR Tb is mainly due to poor compliance, high rate of side reaction of secondary drugs, and limitation in number of available drugs. Thus, to improve the outcome of MDR Tb, it is crucial to make individualized adequate prescription based on the knowledge of the patterns of resistance to each drugs in the community as well as the natural history. The purpose of present study is to evaluate the clinical features of Korean MDR Tb patients including patterns of drug resistance and success rate of treatment which was prescribed according to the sensitivity tests. Methods: Retroscpective analysis of 71 Korean patients with MDR Tb was made. All strains isolated from patients showed resistence to at least two first line drugs. Patients profile, previous treatment history, patterns of drug resistance, outcome of treatment was analysed. Initial treatment regimen was selected according to the previous treatment history and was modified according to the sensitivity reports. The regimen was composed to include at least 4 sensitive drugs when possible. Results: The patients showed resistance to 4.1 drugs on average. 90% of them were resistant to INH and RFP. Among 71 patients, 35 patients(49%) had cavitary lesions in CXR. Treatment outcome was analysed in 55 patients. 35 patients(67%) were improved after treatment and 18 patients(33%) showed treatment failure. 5 patients showed primary resistance. Treatment outcome could be evaluated in 4 of them and all showed improvement after treatment. 14 patients(20%) had to change their regimens due to drug side effects. The most frequent side effect was elevation of liver enzymes(6 patients). Others included dizziness, hyperuricemia, tinnitus, skin rash, GI troubles. More than 50% of side effects developed within 3 months. In repeated drug sensitivity test, the concordance rate of resistance to INH was 100% and RFP 98%. EMB, PZA showed 80% concordance rate. But in the other drugs, the concordances were less than 50%. Operation was done in 5 patient - 1 patients as a adjunctive means of chemotherapy -. In that case, negative conversion of sputum AFB was done. Conclusion: 2/3 patients of multidrug-resistant tuberculosis were improved by appropriate prescription and regular medication suggesting that more aggressive management and monitoring is indicated in multidrug-resistant tuberculosis.

• Journal of Korean Clinical Nursing Research
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• v.26 no.2
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• pp.198-206
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• 2020

Purpose: The rapid response team is a patient safety system that detects symptoms and signs of deteriorating inpatients and provides intervention and treatment. This study analyzed the factors influencing the activation time of the team. Methods: This is a descriptive correlation study that analyzed the electronic medical records of patients activated by the rapid response team. The collection period was from January 2014 to December 2017. We analyzed 278 pieces of data activated by the rapid response team for patients aged 16 years or older at C University S Hospital in Seoul. We employed the SPSS 23.0 program for data analysis. Results: The reasons for activation of the rapid response team were oxygen saturation of less than 90.0%, other causes, and change in consciousness. The most common diagnosis of activated patients was respiratory failure (32.4%). The average activation time was 153.43±286.05 min. The activation time was shortest during convulsions (13.29±7.32 min). For patients with a history of kidney disease (B=0.58, p=.008), in case of surgery (B=0.55, p<.001), if the first symptom is mediated by the physician (B=0.53, p=.007) the active time is often extended. On the other hand, activation time is reduced when consciousness changes (B=-0.51, p=.002), especially when oxygen saturation is below 90.0% (B=-0.64, p<.001). Conclusion: Based on the results of the study, it is expected that patients deteriorating in the general ward would be recognized early, which will help in the effective activation of the rapid response team.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.323-327
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• 2008

Systemic lupus erythematosus (SLE) is a multisystem disorder where the etiology is not clearly known. Symptomatic chronic interstitial pneumonitis is an uncommon manifestation, with a reported prevalence of 3~13%. Achalasia is rare disease that presents with failure in the relaxation of the esophagus sphincter. A 22-year-old woman was admitted to our hospital because of fever, cough and dyspnea. The patient had a history of pericardial effusion and Raynaud's phenomenon. The results of laboratory tests indicated the presence of lymphopenia and included positive antibody tests for antinuclear antibody and anti Sm antibody. A chest X-ray demonstrated the presence of peribronchial infiltration on both lung fields. A Chest CT image showed interlobar septal thickening, ground-glass opacity and a honeycomb appearance in both lung fields and esophageal dilatation with air fluid level. An esophagogram showed the presence of dilated esophagus ends that represented the non-relaxed lower esophageal sphincter. Manometry demonstrated incomplete sphincter relaxation. The case was diagnosed as systemic lupus erythematosus associated with interstitial pneumonia and achalasia.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.121-128
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• 2020

The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

• Journal of the Korean GEO-environmental Society
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• v.14 no.10
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• pp.39-47
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• 2013

Recently, there have been various domestic construction activities related to the reclamation of the dredged soils to expand the land use. However, the reclaimed grounds made of the dredged soils cause various problems due to highly compressible and low shear strength nature. Particularly, this nature induces huge problems in case of the harbor facilities and road construction on the reclaimed sites. Furthermore, in the reclamation activities, the marine dredged soils are often used instead of the well sorted sand, which induces problems of compressibilities. Therefore, in this study, the mechanical characteristics of artificial soil mixture of kaolinite representing the marine dredged soils and the pond ash. A large consolidometer is designed and manufactured to produce the artificial soil mixture. To represent various mixing ratio between the fly ash and bottom ash in the pond ash, six samples with the same stress history are made with different mixing ratio among kaolinite, bottom ash and fly ash. Isotropically consolidated and undrained compression tests are performed to investigate the shear characteristics of soil mixtures. Based on the experimental results, as the components of mixed ash increase, the friction angle increase and the cohesion values decrease. Also, the porepressure parameters at failure, Af increase with the mixing components of the pond ash. The portion of bottom ash has more impact on the shear behavior than that of fly ash.

• Journal of the Korean Geotechnical Society
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• v.37 no.7
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• pp.13-23
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• 2021

If roads, bridges, buildings, etc. are built on the ground with soft clay or organic soil, there may be a lot of problems in geotechnical engineering such as settlement and stability due to the large settlement and lack of bearing capacity. In extreme cases, it may appear due to shear failure or collapse of the constructed structure, so a ground improvement method is indispensable to increase the strength of the ground and to suppress settlement. In this study, the settlement according to each groundwater level condition was analyzed using the measurement results for the groundwater level conditions, one of the important factors in predicting the settlement in dredged and reclaimed ground, and the groundwater level conditions applied to the settlement analysis were proposed by comparing it with settlement generated 5 years after construction. As a result of the analysis, it is judged that it is reasonable to apply the measured groundwater level during construction and the low water ordinary neap tide (L.W.O.N.T) during load application for the groundwater level in the settlement analysis. In addition, in the case of the dredged and reclaimed ground, it is estimated that the water pressure acting on the clay layer is nonlinear, as the result of the observations of the head of water at the observation points above and below the in-situ clay layer were different.