• The korean journal of orthodontics
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• v.39 no.3
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• pp.185-198
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• 2009

Tooth anklylosis is defined as the adhesion state of alveolar bone to dentin or cementum. Trauma, disturbed metabolic disease, and congenital disease have been given as etiologic factors. Complications of tooth ankylosis are tipping of the neighboring teeth, space loss, and supraeruption of the opposing teeth. Particularly if dental ankylosis occurs in maxillary incisors of a growing child, the ankylosed tooth can not move vertically with subsequent disturbance in vertical growth of the alveolar process. With an appropriate treatment approach, an esthetic condition must be achieved especially in the maxillary anterior region. In this report, two cases are presented which were treated by the surgical repositioning method. One is treated by alveolar bone distraction osteogenesis which used a tooth-borne type distraction device and the other by single tooth osteotomy.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.181-185
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• 2012

Dens invaginatus is a developmental anomaly resulting in a deepening or invagination of the enamel organ into the dental papilla prior to calcification of the dental tissues. The most widely used classification of dens invaginatus is the system described by Oehler categorizes invaginations into three classes as determined by how far they extend radiographically from the crown into the root. Oehler's classification type III is that the invagination extends through the root and communicates with the periodontal ligament. There is usually no communication with the pulp. In Type III lesions, any infection within the invagination can lead to an inflammatory response within the periodontal tissues giving rise to a 'peri-invagination periodontitis'. In the cases presented here, we treated two patients who were refered for 'peri-invagination periodontitis' on maxillary lateral incisor with Oehler's type III invagination by different approaches each, and they have shown satisfactory outcomes. Although there are several approaches to the management of dens invaginatus, the most important objective is to preserve the health of the pulp, which can be achieved by early diagnosis and the prophylactic treatment regardless of severity. When disease has developed, decision has to be made whether to treat the invagination and the pulp separately.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.35-40
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• 2016

The maxillary defects lead to anatomical and functional deformity of the maxillofacial region. As far as functions are concerned, such defects can produce difficulty in speech, mastication, and deglutition. Obturator prostheses play a very important role in functional recovery for post-maxillectomy patients. To achieve rigidity of the obturator, appropriate retention should be given, and the weight of the prosthesis be reduced. There are two types of hollow bulb obturator: open and closed. A closed type has many advantages. Nevertheless, some problems, including complexity of fabrication and water leakage into the bulb, have the closed hollow obturator not be widely used. The one-step polymerization technique described in this case overcomes the shortcomings by easily constructing a small hollow bulb with two thermoplastic resin sheets.

• The Korean Journal of Mycology
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• v.11 no.4
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• pp.163-167
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• 1983

Oyster mushroom, Pleurotus ostreatus, was exposed to 0.625, 1.25, 2.5 and 5.0 ppm $SO_2$ for 15, 30, 60, 120 and 180 minutes at the tiny button stage in order to study the effect of sulfur dioxide on growth and cap discoloration of the mushroom. The cap color was changed from grey to greyish blue at low dosage of sulfur dioxide, and with the lapse of exposing time and rasing sulfur dioxide concentration up, the color was changed to light brown and dark brown. The cap dicoloration was begun by the exposure of sulfur dioxide to 0.625 ppm for 120 minutes, to 1.25 ppm for 30 minutes and to 2.5 ppm for 15 minutes. By the exposure of sulfur dioxide to 1.25 ppm for 120 minutes, to 2.5 ppm for 30 minutes, its growth was inhibited, but the fruit body was died by the exposure of the gas to 2.5 ppm for 180 minutes and to 5.0 ppm for 60 minutes. Sulfur dioxide inhibited conspicuously the development of basidia and basidiospores of the mushroom and 20 to 25 percent of basidiospores formed were abnormal. Ethylene production by mushroom exposed to sulfur dioxide was not recognized.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.128-136
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• 2005

The objective of this study was to determine the effect of calcium concentrations in fertilizer solution on growth and cut flower quality of chrysanthemum 'Biarritz' To achieve this, deficiency symptom and growth characteristics as influenced by controlled Ca concentrations in fertilizer solution were investigated. The analysis of plant tissue and soil solution of root media were also conducted to secure optimum concentration for plant growth. Calcium deficiency developed on the very youngest leaves and the young leaves developed 'cupped' shape as they expand. The cut flower length of 0, 3.0 and 6.0 mM treatments were 105.8, 106.5, and 107.3cm, respectively. Elevated Ca concentration within the range from 0 to 6.0mM in fertilizer solution increased cut flower weight. The cut flower weight of control and 6.0mM treatment were 51.6 and 59.4 g, respectively. The tissue Ca content of 6.0mM treatment in which crops showed the highest growth among treatments was $3.09\%$ based on the dry weight of the youngest fully expanded leaves. From the results, it seems necessary to maintaining tissue Ca content higher than $2.8\%$. Soil Ca concentrations increased as K concentrations in fertilizer solution were elevated. Ca concentration in 0.0, 1.5, 3.0, 4.5 and 6.0mM treatments were 5.0, 7.4, 12.1, 16.5 and $28.2mg{\cdot}L^{-1}$, respectively, at harvesting stage. It is suggested that Ca concentration higher than $25.4mg{\cdot}L^{-1}$ in soil solution of root media is required to maintain normal growth.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.30-35
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• 2001

This experiment was undertaken to investigate the effect of root zone temperature during the night on absorption of mineral nutrients, growth, and fruit yield of the truss-limited hydroponic tomatoes in winter. The root zone temperature was either controlled to 10, 15, 20, $25^{\circ}C$, or left uncontrolled at ambient temperatures. Temperature of the covered beds rose as root zone temperature was raised, but it in all treatments was less than 3$^{\circ}C$ higher than that in the control. Raising root zone temperature, except $25^{\circ}C$, showed positive effect on plant height, leaf length, stem diameter, and plant fresh and dry weight, but not on T/R ratio which was the greatest in the control. Root activity in all treatments except $25^{\circ}C$ increased as compared to the control. Mean fruit weight, fruit count per plant, and fruit yield were the greatest in 2$0^{\circ}C$ treatment. Root zone temperature did not significantly affect the contents of total nitrate and magnesium in leaves, stems and roots. Concentrations of phosphate and calcium increased in leaves and stems, but decreased in roots as root zone temperature increased. Overall, 2$0^{\circ}C$ treatment gave the greatest growth and energy efficiency.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.79-84
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• 2001

To investigate contributory factors of CSF shunt failure, 237 patients, who underwent shunt placement from January 1995 to December 1998 at our hospital, were reviewed retrospectively. The causes of the hydrocephalus were tumor, hemorrhage, infection, congenital anomaly, normal pressure hydrocephalus, trauma and others. One hundred nine revisions of CSF shunting were done during follow up periods. The causes of shunt revisions were mechanical obstruction, malposition, infection and others. The contributory factors of CSF shunt failure and shunt survival rate were analyzed using SPSS. The shunt survival rate at 1, 2 and 3 years after procedure was 77.1%, 75.4%, 74.1% respectively. In the young age group below 10 years old, postinfectous hydrocephalus was the most common high risk factor for shunt revision. In conclusion, the most shunt failures developed in the first year after surgery and the age and causes of the hydrocephalus were major determinant factors of shunt revision.

• International Area Studies Review
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• v.14 no.2
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• pp.43-60
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• 2010

This paper measures R&D efficiency and productivity changes of 24 nations including Korea, Japan and China by the non-parametric Malmquist productivity index. The principle findings of this study are as follows. First, R&D efficiency scores of Korea and Japan are 0.837 and 0.834 respectively. Meanwhile China shows 0.420, the worst performance among the selected countries. Second, Korea marked annual productivity increase of 25%, highest among the selected countries', for 2000-2005. R&D productivity in Japan and China, however, decreased 1.9% and 0.9% respectively. Third, annual rates of technology change and technical efficiency change in Japan are 0.6% and -2.5%. Therefore decrease of productivity in Japan is mainly due to technical inefficiency. In case of China, improvement of technical efficiency is the main contributor to productivity growth but technical progress has edged downward in the sample period. In Korea, with annual rate of technology change and technical efficiency change being 5.2% and 18.2% respectively, both efficiency improvement and technical progress has pulled the R&D productivity growth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.180-187
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• 2021

Many young people, who are most affected by TV audition programs and the K-pop craze, have begun to choose careers in music. They attended music classes through academies or took private lessons, and then went on to a college's practical-music department. As the number of applicants increased, competition for university practical-music programs increased abnormally. As a result, many students then started learning music at an early age through private educational institutions and academies. Afterwards, as high schools related to practical music began to appear, the number of students entering practical-music high school and technical schools increased. However, a big problem in practical-music high schools was difficulty in finding professional teachers who majored in music. This arose because it was difficult for someone with a practical-music major to acquire a full-time teaching certificate. There are many ways to obtain a teacher's license, but the only option for practical-music majors is to graduate from the Graduate School of Education. However, since the Graduate School of Education is limited to classical and traditional music, admission itself is difficult. Even if someone is accepted by the school, most of the courses consist of classical music and traditional music education, which is very difficult for someone who majored in practical music. Therefore, in this thesis, we study the current situation in practical-music high schools, looking at why a regular Level 2 teaching certificate is needed and how to obtain one.

• Journal of the Korean Orthopaedic Association
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• v.53 no.6
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• pp.466-477
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• 2018

Orthopaedics is an area where 3-dimensional (3D) printing technology is most likely to be utilized because it has been used to treat a range of diseases of the whole body. For arthritis, spinal diseases, trauma, deformities, and tumors, 3D printing can be used in the form of anatomical models, surgical guides, metal implants, bio-ceramic body reconstruction, and orthosis. In particular, in orthopaedic oncology, patients have a wide variety of tumor locations, but limited options for the limb salvage surgery have resulted in many complications. Currently, 3D printing personalized implants can be fabricated easily in a short time, and it is anticipated that all bone tumors in various surgical sites will be reconstructed properly. An improvement of 3D printing technology in the healthcare field requires close cooperation with many professionals in the design, printing, and validation processes. The government, which has determined that it can promote the development of 3D printing-related industries in other fields by leading the use of 3D printing in the medical field, is also actively supporting with an emphasis on promotion rather than regulation. In this review, the experience of using 3D printing technology for bone tumor surgery was shared, expecting orthopaedic surgeons to lead 3D printing in the medical field.