• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.417-422
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• 1997

Recombinant Bacillus subtilis LKS88[pASA240] containing the amylase gene from Streptomyces albus KSM-35 was exploited in fed-batch cultivation for mass production of maltotetraose-producing amylase. The effects of dissolved oxygen, additional organic nutrients (peptone and yeast extract) and mixed carbon sources (glucose plus soluble starch) on amylase production were examined in fed-batch operations in an effort to determine the optimum conditions for a maximum amylase productivity. Under the optimum conditions, maximum amylase activity was about 4.2 times higher than that obtained in batch cultivations, indicating that mass production of maltotetraose-producing amylase could be accomplished in fed-batch cultivation of the recombinant B. subtilis strain.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.63-75
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• 2020

When tunnel is excavated via drilling and blasting, the excessive overbreak is the primary cause of personal or equipment safety hazards and increasing the cost of the tunnel operation owing to additional ground supports such as shotcrete. The practical management of overbreak is extremely difficult due to the complex causative mechanism of it. The study examines the relationship between rock mass characteristics (unsupported face condition, uniaxial compressive strength, face weathering and alteration, discontinuities- frequency, condition and angle between discontinuities and tunnel contour) and the depth of overbreak through using feed-forward artificial neuron networks. Then, Overbreak Resistance Factor (ORF) has been developed based on the weights of rock mass parameters to the overbreak phenomenon. Also, a new concept of tunnel overbreak management system using ORF has been suggested.

• Archives of Reconstructive Microsurgery
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• v.26 no.1
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• pp.23-25
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• 2017

The malignant peripheral nerve sheath tumor (MPNST) originates from neurofibromatosis type 1 (NF1). Because NF1 patients have many accompaniments with growth of additional masses, they usually overlook potential malignant changes in their masses. Our patient had two growing mass near the left elbow for several months; however, she ignored these masses until 7 days prior to writing this article, at which time they began bleeding. Traditionally, sarcoma including MPNST treatment consisted of amputation of the involved extremity. However, treatment now consists of surgical resection with adjuvant therapy. Therefore, we conducted resection of the mass and subsequent coverage with a local advancement flap. We believe that the most effective treatment for MPNST is early diagnosis and fast surgery, coupled with notification that there is always potential for malignant change in NF1 patient's masses.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.46-51
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• 2012

This study aims to develop the performance analysis program on the staged combustion cycle of the liquid rocket engine using liquid oxygen(LOx) as oxidizer, liquid hydrogen(LH2) and RP-1 as fuel. The developed analysis program can obtain the propellant mass flow rate, the specific impulse, and representative design values of engine components for the required thrust satisfying pressure, mass flow, and energy balance conditions. The analysis results show that the the specific impulses (Isp) compared to those of the real engines have been less than 1%. With additional constraints, the program will be improved for the system optimization.

• Archives of Craniofacial Surgery
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• v.20 no.4
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• pp.274-278
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• 2019

Orbital tuberculosis is a rare form of extrapulmonary tuberculosis, even in endemic areas. It may involve the soft tissue, lacrimal gland, periosteum, or bones of the orbital wall. We present a case of orbital tuberculosis on the lower eyelid. An 18-year-old woman with no underlying disease visited our clinic for evaluation of an oval nodule ($1.5{\times}1.2cm$) on the right lower eyelid. Incision and drainage without biopsy was performed 2 months ago in ophthalmology department, but the periorbital mass had deteriorated, as the patient had erythematous swelling, tenderness, and cervical lymphadenopathy. Visual acuity was normal; there were no signs of proptosis, diplopia, or ophthalmoplegia. Computed tomography revealed a small abscess cavity without bony involvement. We performed an excision and biopsy through a percutaneous incision under local anesthesia. Histological examination revealed a granuloma and was diagnosed as orbital tuberculosis. The patient was additionally treated with anti-tuberculosis therapy for 6 months and recovered without complication or recurrence by 7 months. Orbital tuberculosis occurs in patients with or without associated pulmonary tuberculosis, and should be considered as a differential diagnosis in patients with inflammatory orbital disease and an orbital mass. If recurrence occurs despite adequate initial treatment, we recommend an additional examination and excisional biopsy.

• Archives of Craniofacial Surgery
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• v.20 no.3
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• pp.181-185
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• 2019

Intraosseous hemangioma is a rare, slow-growing, benign tumor of blood vessels. Primary hemangioma of the skull is a benign lesion that may appear as a palpable mass or accidentally detected during image evaluation. Simple radiography is the most commonly used technique to localize a lesion and computed tomography (CT) may help determine the effect of a lesion. We report a case of multifocal intraosseous calvarial hemangioma developed in the subgaleal plane of an elderly male patient. Ultrasonography examination revealed hyperechoic striated septae parallel to the skin and discontinuity of the focal cortex, however, the underlying bone cortex appeared relatively intact. No significant flow is observed on Doppler ultrasonography. Based on these evaluations, the mass was interpreted by a radiologist as a subgaleal lipoma. This case highlights the importance of additional CT examination in a patient presenting with a scalloping sign of the underlying calvarium. Clinicians also should be aware of the possibility of intraosseous calvarial hemangiomas in lesion. Furthermore, the proper choice of congenital vascular malformation term is still quite confusing with misconception present in the literature.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1364-1371
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• 2018

An extensive investigation of photon interaction properties has been made for $Zn_xTe_{100-x}$ alloys (where x = 5, 20, 30, 40, 50) to explore its possible use in sensing and shielding gamma radiations. The results show better and stable response of ZnTe alloys for various photon interaction properties over the wide energy range, with an additional benefit of ease in fabrication due to lower melting points of Zn and Te. Mass attenuation coefficient values show strong dependence on photon energy as well as composition. Effective atomic number has maximum value for $Zn_5Te_{95}$ and lowest for $Zn_{50}Te_{50}$ in the entire energy region. The alloy sample with maximum $Z_{eff}$ shows minimal value of $N_e$ and vice versa. Mean free path follows inverse trend as observed for mass attenuation coefficient. The exposure and energy absorption buildup factors depend upon photon energy, penetration thickness and composition (effective atomic number) of $Zn_xTe_{100-x}$ alloys. It finds its application for sensing and shielding from highly energetic and highly penetrating photons at sites where radioactive materials were used and visibility of material is not a big constraint. Further, energy down conversion property of ZnTe alloys with subsequent emission in green band suggests its potential use in sensing gamma photons.

• The Korean Journal of Emergency Medical Services
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• v.24 no.3
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• pp.147-154
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• 2020

Purpose: The purpose of the study was to investigate traumatic urethral injury in a 63-year-old patient with hematuria. Methods: A hematuria patient was transferred by paramedics. At the time of the visit, the patient's blood pressure (151/91mmHg), pulse rate (86/min), body temperature (37.1℃), and other vital signs were stable. Their KTAS (Korean Triage and Acuity Scale) was Level 4. The patient had no damage to the injured area, but a large contrast defect was observed between the prostate urethra and the bladder in urethral angiography performed due to persistent hematuria and pain in the injured area. Results: Following radiological evaluation of a suspected liposarcoma or neuroma mass of the prostate urethra, the mass was removed through urethral tumor resection. The result of histologic evaluation provided a diagnosis of highly differentiated invasive urethral cell carcinoma that had invaded the muscle layer. The patient was given additional treatment for urethral cancer but was rejected and is currently being followed. Conclusion: The prognosis for urinary tract cancer has distinct differences for patients with lymph node metastasis and tumor characteristics. The presence or absence of urethral cancer should be confirmed through angiography, CT, MRI, and cystoscopy.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3962-3973
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• 2022

Several critical heat flux (CHF) correlations including the look-up table in the MARS code have been assessed for the prediction of CHF in a downward-flow narrow rectangular channel. For the assessment, we built an experiment database that covers pressures between 1.01 and 39.0 bar, gap sizes between 1.09 and 6.53 mm, mass fluxes up to 25,772 kg/m²s, and under one-sided and two-sided heating conditions. The results of the assessment showed that the Kaminaga correlation has the best overall prediction compared to others. However, because the correlation uses global variables, such as inlet and outlet subcooling and total heat transfer area, it is difficult to use in a system code. A new CHF correlation is then proposed by replacing the global variables in the Kaminaga correlation with local ones and adding correction factors to consider the effect of gap size, mass flux, and the number of heating walls. Additional correction factor is added to consider the effect of inlet subcooling. It is shown that the new one is better than the Kaminaga correlation and it is easy to implement to any system code.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3918-3929
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• 2021

In this study, we experimentally investigate of a two-phase natural circulation loop that functions as a passive containment cooling system (PCCS). The experimental apparatus comprises two loops: a hot loop, for simulating containment under severe accidents, and a natural circulation loop, for simulating the PCCS. The experiment is conducted by controlling the pressure and inlet temperature of the hot loop in the range of 0.59-0.69 MPa (abs) and 119.6-158.8 ℃, respectively. The heat balance of the hot loop is established and compared with a natural circulation loop to assess the thermal reliability of the experimental apparatus, and an additional system is installed to measure the vapor mass flow rate. Furthermore, the thermal-hydraulic characteristics are considered in terms of a temperature, mass flow rate, heat transfer coefficient (HTC), etc. The flow rate of the natural circulation loop is induced primarily by flashing, and a distortion is observed in the local HTC because of the fully develop as well as subcooled boiling. As a result, we present the amount of heat capacity that the PCCS can passively remove according to the experimental conditions and compared the heat transfer performance using Chen's and Dittus-Boelter correlation.