• Journal of Korean Neurosurgical Society
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• v.62 no.5
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• pp.586-593
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• 2019

Objective : To study risk factors of secondary lumbar discectomy (LD) for recurrent herniated lumbar disc (HLD) and identify methods to lower the rate of recurrence. Methods : Data from 160 patients who underwent primary LD were collected retrospectively. Demographic features, radiologic findings including Pfirrmann disc degeneration, and surgical information were analyzed to compare risks between revision and non-revision patients. Results : The revision rate was 15% (24 patients), and the mean follow-up was 28.3 months. HLD recurrence was not related to any demographic characteristics. Primary and secondary LD were most common at the L4-5 level, but the level of operation was not significantly associated with revision. Primary LD most commonly had a Pfirrmann disc degeneration grade of 3, followed by 4. For recurrent HLD, Pfirrmann grade 4 was most common and was statistically significant (p<0.05). A body mass index (BMI) over 30 was considered obese and was significantly related with HLD revision (p<0.05). Conclusion : Patients with high BMI or severe disc degeneration should be informed of HLD revision.

• Proceedings of the KSCN Conference
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• 2000.11a
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• pp.70-70
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• 2000

• Proceedings of the KSCN Conference
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• 1999.05a
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• pp.122-122
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• 1999

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.773-781
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• 2004

This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.

• Brain Tumor Research and Treatment
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• v.6 no.2
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• pp.97-100
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• 2018

Meningioma is relatively common, benign, and extra-axial tumor accounting for about 20% of primary brain and spinal cord tumors. The World Health Organization (WHO) classified these tumors into Grade I (benign), Grade II (atypical), and Grade III (anaplastic) meningioma. Grade I meningioma which is slowly growing tumor and have some rare subtypes. Among them, metaplastic subtype is defined as a tumor containing focal or widespread mesenchymal components including osseous, cartilaginous, lipomatous, myxoid or xanthomatous tissue, singly or in combinations. We report a rare metaplastic meningioma overspreading nearly whole cerebral convexity from main extra-axial tumor bulk in the parietal lobe.

• Journal of Korean Elementary Science Education
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• v.17 no.2
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• pp.67-77
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• 1998

The result of studying primary science education in Korea the first stage under CHOSUN Government General is as follows and it could be seen that it was managed under considerably different philosophy of education than that of the Ministry of Education, Japan. 1) Weekly 2 hours of 'science' were taught at 3rd and 4th grade of primary school. 2) CHOSUN Government General emphasized 'practicality' in the regulation of primary science education. 3) During the transitional period science text compiled by the office of education was revised and used. 4) First primary science text compiled by CHOSUN Government General was "Science Textbook for Commom School" (1913) and it was filled with sentences stimulating interest of students and at end of each chapter there were exercise problems.

• Journal of Korean Neurosurgical Society
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• v.41 no.3
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• pp.186-189
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• 2007

Metastasizing mixed tumors [MMT] of salivary glands are inexplicably metastasize maintaining benign histology. There is no pathologic and flow cytometric analysis criteria to predict the metastasis. MMT is known to metastasize by local implantation, vascular and lymphatic embolization after multiple surgery to local recurrences of primary tumor. However, multiple metastasis including cranium and spine occurred even without surgery to the primary tumor in this case. No pathological evidence of malignancy could be found in both primary and metastatic tumor. MMT is considered as an low grade malignancy based on clinical behavior rather than histologic evidence, such as low mortality rate, long delay of metastasis after primary lesion. Cranial metastasis is also extremely rare and only two cases have been reported. We report this unusual case with a literature review.

• Education of Primary School Mathematics
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• v.3 no.2
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• pp.109-113
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• 1999

To improve the elementary student's ability to classify the data and obtain the information from the data through graphics, it is necessary to use the teaching and learning material which encourage the student to study with interest and is adjacent to the student's environment. In this thesis. several materials to satisfy the condition is proposed together with some remarks to direct the teaching. These materials is recommended to use for the maturity learning and teaching in grade 6.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.163-171
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• 2017

Purpose: Although stereotactic ablative body radiotherapy (SABR) is widely used therapeutic technique, predictive factors of radiation pneumonitis (RP) after SABR remain undefined. We aimed to investigate the predictive factors affecting RP in patients with primary or metastatic lung tumors who received SABR. Materials and Methods: From 2012 to 2015, we reviewed 59 patients with 72 primary or metastatic lung tumors treated with SABR, and performed analyses of clinical and dosimetric variables related to symptomatic RP. SABR was delivered as 45-60 Gy in 3-4 fractions, which were over 100 Gy in BED when the ${\alpha}/{\beta}$ value was assumed to be 10. Tumor volume and other various dose volume factors were analyzed using median value as a cutoff value. RP was graded per the Common Terminology Criteria for Adverse Events v4.03. Results: At the median follow-up period of 11 months, symptomatic RP was observed in 13 lesions (12 patients, 18.1%), including grade 2 RP in 11 lesions and grade 3 in 2 lesions. Patients with planning target volume (PTV) of ${\leq}14.35mL$ had significantly lower rates of symptomatic RP when compared to others (8.6% vs. 27%; p = 0.048). Rates of symptomatic RP in patients with internal gross tumor volume (iGTV) >4.21 mL were higher than with ${\leq}4.21mL$ (29.7% vs. 6.1%; p = 0.017). Conclusions: The incidence of symptomatic RP following treatment with SABR was acceptable with grade 2 RP being observed in most patients. iGTV over 4.21 mL and PTV of over 14.35 mL were significant predictive factors related to symptomatic RP.

• Journal of Science Education
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• v.34 no.1
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• pp.105-112
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• 2010

The purpose of this research was to investigate relations between prior knowledge and primary grade science brilliant intellect's observation and inquiry. The subjects were selected 'Spider and cobweb' that self-regulation quest is available. Subjects were divided into two groups with one group having no prior knowledge about research subject. Compared observation method question type and level that appear between subject achievement to group. Target learning group are 5 ~ 6 school year 17 people for national university for the gifted center of local middle city. Researcher collected and analyzed data using summer vacation concentration education period. Source collection subject's research recording paper, subject's voice recording device, interview data etc. A data analysis tool took advantage of observation method that is studied in existing, question type, question level. Research was able to conclude : First, observation of prior knowledge happened than mass of students who many mass of students are few relatively vigorously. Second, primary grade science brilliant intellect students used more mainly manufacturing observation than simplicity observation that use senses regardless of relative quantity of prior knowledge. Third, prior knowledge expressed variety when many mass of students observe operation relatively.