• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.47-47
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• 2011

There have been numerous efforts to enhance the efficiency of light-emitting diodes (LEDs) by using low dimensional structures such as quantum dots (QDs), wire (QWRs), and wells (QWs). We demonstrate QD/QWR/QW hybrid structured LEDs by using nano-scaled pyramid structures of GaN with ~260 nm height. Photoluminescence (PL) showed three multi-peak spectra centered at around 535 nm, 600 nm, 665 nm for QWs, QWRs, and QDs, respectively. The QD emission survived at room temperature due to carrier localization, whereas the QW emission diminished from 10 K to 300 K. We confirmed that hybrid LEDs had zero-, one-, and two-dimensional behavior from a temperature-dependent time-resolved PL study. The radiative lifetime of the QDs was nearly constant over the temperature, while that of the QWs increased with increasing temperature, due to low dimensional behavior. Cathodoluminescence revealed spatial distributions of InGaN QDs, QWRs, and QWs on the vertices, edges, and sidewalls, respectively. We investigated the blue-shifted electroluminescence with increasing current due to the band-filling effect. The hybrid LEDs provided broad-band spectra with high internal quantum efficiency, and color-tunability for visible light-emitting sources.

• The korean journal of orthodontics
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• v.45 no.6
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• pp.289-298
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• 2015

Objective: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs). Methods: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth. Results: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle. Conclusions: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.3
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• pp.106-111
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• 2018

Halide perovskite nanocrystals have become attractive for LED applications due to their high color purity and excellent luminescent properties. $CsPbX_3$ (X = I, Br, and Cl) nanocrystals were synthesized by hot-injection method and the emission wavelength was controlled by changing the composition of halide ion. Green- and red-emitting films were fabricated using a polymer binder. The outstanding optical properties of the synthesized nanocrystals and fabricated films were confirmed. The wLED designed by green- and red-emitting perovskite nanocrystal films on blue InGaN LED was characterized.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.289-303
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• 2006

This study was performed to evaluate the effect of bone graft materials including demineralized freeze-dried bone, freeze-dried bone, deproteinized bovine bone on space-making capacity and bone formation in guided bone regeneration with titanium reinforced ePTFE membrane(TR-ePTFE). Adult male rabbits(mean BW 2kg) were used in this study. Intramarrow penetration defects were surgically created with round bur on calvaria of rabbits. TR-ePTFE membrane was adapted to calvarial defect and bone graft materials were placed. Animals were sacrificed at 2, 8, 12 weeks after surgery. Non-decalcified specimens were processed for histologic analysis and prepared with Villaneuva bone stain. The results of this study were as follows: 1. TR-ePTFE membrane was biocompatible and capable of maintaining the space-making. 2. Tissue integration was not good at TR-ePTFE membrane. Fixation was not enough. so, wound stabilization was not good. 3. In animals using deproteinized bovine bone, demineralized freeze-dried bone, bone formation was little. 4. In animals using freeze-dried bone, bone formation was better. Within the above results, bone formation may be inhibited when wound stabilizafion was not good.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.272-278
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• 2011

Recently, the performance of binaural hearing aids is rapidly improved with the technology advancement of wireless communication, digital signal processing, and integrated circuit design. However, the previous hearing aids developer platforms can't be applied to binaural hearing aids developing, because it has no consideration for wireless communication and binaural hearing control. Also, the previous developer platforms are not easy to use for the algorithm development, because programming languages are limited. In this paper, we designed and implemented the open platform board for binaural hearing aids developing. The designed board can be programmed by general programming language and can be used wireless communication module. In order to verify the designed open platform board, we used the volume control algorithm using two open platform board. As a result of experiment, we verified the performance of designed and implemented open platform board that was successfully operated the binaural hearing control and the wireless communication.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.515-520
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• 2016

This study was carried out to investigate the component and immunoregulatory effects of Sparassis crispa stipe. Herein, S. crispa was divided into the pileus and stipe to compare their ingredients (${\beta}-glucan$), antioxidant activity (in vitro), and the immunoregulatory function (cytokines, leukocytes, and spleen weight). The ${\beta}-glucan$ content in each part showed about 1.8 times higher content in the stipe than that in the pileus. The stipe also showed a higher total phenol content and antioxidant activity than the pileus. The cytokines $TNF-{\alpha}$, IL-2, and IL-10 have adjusted in the S. crispa extract-injected groups. In addition, the number of leukocytes was also significantly elevated in the rats administered with the S. crispa stipe extract. These results suggest that the stipe of S. crispa has great potential as an ingredient in functional foods.

• The Journal of Traditional Korean Medicine
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• v.15 no.1
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• pp.77-82
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• 2006

Lavandula vera is indispensable member of the herb family, used for perfumes and potpourri. Androgens have profound effects on the physiology of the sebaceous gland. Sebum is secreted due to the effect of androgen, which starts to be secreted at puberty. Using the human sebocyte cell line SZ95. the author investigated the inhibitory effect of Lavandula vera on the lipid production. Light microscopic finding were examined numerous cytoplasmic lipid droplets SZ95 cells by Oil red staining and lipid droplets were increased markedly by testosterone. On the other hand, combined treatment with Lavandula vera and testosterone resulted in a lower lipid droplets than with testosterone alone in a dose-dependent manner. These findings indicate that Lavandula vera acts antagonistically to testosterone and inhibits the lipid synthesis of SZ95 cells at the cellular level.

• Korean journal of dermatology
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• v.56 no.10
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• pp.594-602
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• 2018

Background: Acute generalized exanthematous pustulosis (AGEP) is typically a medication-induced acute febrile eruption. Few large-scale studies have reported clinical data regarding AGEP in Korea. Objective: This study analyzed the clinical and histopathological features of AGEP in Koreans to identify recent trends in this context. Methods: This study retrospectively reviewed 31 patients with AGEP. Age, sex, clinical features, etiologies, laboratory findings, histopathological features, and treatment outcomes were obtained from patients' medical records and photographs. Results: The mean age of onset was 43.6 years, and the male : female ratio was 2.1 : 1. All patients showed non-follicular tiny pustules and erythema. Fever was reported in 13 patients and neutrophilia in 17 patients. Medications were considered the most common etiological contributors. Twenty patients showed drug-induced AGEP, and 11 of 20 patients showed antibiotic-induced AGEP. Serum C-reactive protein and lactate dehydrogenase levels increased in 93.8% and 77.8% of the patients, respectively. Histopathologically, all patients showed subcorneal or intraepidermal pustules, followed by exocytosis and neutrophilic dermal infiltrate. Twenty-five patients improved within a mean period of 7.5 days after the onset of the skin rash. The percentage of women in the drug-induced AGEP group was significantly higher than that in the non-drug-induced AGEP group. Conclusion: This report describes a large-scale study that analyzed the clinical and histopathological features of AGEP in Koreans and seems to accurately reflect the recent trends in this context. Clinically, it is important to note that the percentage of women in the drug-induced AGEP group was higher than that in groups showing other etiologies of AGEP.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.421-430
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• 2020

Purpose: Currently, there is no clear evidence to support any specific treatment as a principal therapy for stage IV gastric cancer outlet obstruction (GCOO) patients. This study evaluated the outcomes of palliative gastrectomies and survival prognostic factors in patients with stage IV resectable GCOO. Materials and Methods: We retrospectively reviewed the medical records of 48 stage IV GCOO patients who underwent palliative gastrectomies between June 2010 and December 2019. Palliative gastrectomies were performed only in patients with resectable disease. Early surgical outcomes and prognostic factors were analyzed using univariate and multivariate analyses. Results: There were no specific risk factors for postoperative complications, except for being underweight. Severe postoperative complications developed in five patients, and most of the patients underwent interventional procedures and received broad-spectrum antibiotics for intra-abdominal abscesses. The multivariate survival analysis showed that palliative chemotherapy is a positive prognostic factor, while the specific type of hematogenous and lymphatic metastasis is a negative prognostic factor. Conclusions: We recommend that the treatment method for stage IV GCOO should be selected according to each patient's physical condition and tumor characteristics. In addition, we suggest that palliative gastrectomies can be performed in stage IV resectable GCOO patients without unfavorable prognostic factors (types of hematogenous and lymphatic metastases).

• Safety and Health at Work
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• v.12 no.1
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• pp.102-107
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• 2021

Background: This study was conducted to identify the association between sleep duration and suicidal ideation among farmers in Korea. Methods: We used Safety for Agricultural Injuries of Farmers cohort data collected from September 2015 to June 2018, which was an agricultural survey on the health and behaviors of adult farmers in Jeju island, Korea. Results: A total of 964 participants were included in the analysis, and 3.7% of them were identified with having suicidal ideation. The frequencies of average daily sleep duration of <6 h (short sleep), 6-8 h (normal sleep), and >8 h (long sleep) were 24.4%, 70%, and 5.6%, respectively. Multivariate analyses revealed that short sleep duration was significantly associated with suicidal ideation compared with normal sleep duration (odds ratio = 2.49, 95% confidence interval = 1.07-5.77). Conclusion: Our findings suggest that short sleep duration in farmers result in higher suicidal ideation. Because individuals who have suicidal ideation often commit suicide, careful monitoring is required to prevent suicide in farmers with short sleep duration.