• Electronics and Telecommunications Trends
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• v.39 no.5
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• pp.61-73
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• 2024

Quantum information technology is driving innovative computing, communication, and sensing advancements. High-performance tunable lasers have become essential tools for precisely controlling and manipulating qubits. These lasers provide high stability and accuracy at specific wavelengths, enabling efficient control of various types of qubit systems, such as ions, neutral atoms, and defects. High-performance tunable lasers allow the initialization of qubit states, execution of quantum gate operations, and minimization of errors during the readout process. In addition, tunable lasers are critical in precisely regulating the interactions between multiple qubits to optimize quantum entanglement and correlation. This study explores the existing and state-of-the-art technologies related to the design and implementation of high-performance tunable lasers in the visible and near-infrared wavelength ranges that are crucial for key material systems used in quantum technology. Based on this investigation, we present new methodologies for maximizing the scalability of qubit control. These laser technologies are expected to contribute to the commercialization and performance enhancement of quantum information technology, a common foundational technology.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.339-350
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• 2017

Purpose: The purpose of this study was to determine the critical diabetes duration in a streptozotocin (STZ)-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration by evaluating the association between diabetes duration and bone healing capacity through histological and radiographic analyses. Methods: Experimental diabetes was induced in 50 of 60 rats by an STZ injection. The rats were divided into 5 groups, including a control group (group 1), according to diabetes durations of 0, 2, 4, 6, and 8 weeks, respectively. Eighteen rats survived: 4 in group 1, 4 in group 2, 4 in group 3, 5 in group 4, and 1 in group 5. Calvarial defects were created at 0, 2, 4, 6, and 8 weeks after STZ injection in groups 1-5. Cone-beam computed tomography scanning was performed at baseline and at 5 and 7 weeks after surgery. The rats were sacrificed 7 weeks after surgery, followed by histological evaluation. Results: The voxel gray values (VGVs) of group 1 and group 2 increased, whereas the VGVs of group 3 and group 4 decreased starting 5 weeks after surgery, although this trend did not reach statistical significance between groups. On the reconstructed 3-dimensional images and based on an analysis of histological features, groups 1 and 2 showed apparent bone regeneration, while groups 3-5 showed very limited bone regeneration. Conclusions: The critical diabetes duration in an STZ-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration was between 2 and 4 weeks. It is suggested that researchers who use STZ-induced diabetic rats wait for more than 2 weeks following diabetes induction before placing implants or conducting bone regeneration studies to allow definite disturbances in bone healing to emerge.

• Tuberculosis and Respiratory Diseases
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• v.61 no.2
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• pp.129-136
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• 2006

Background: To interpret lung function tests, it is necessary to determine the lower limits of normal (LLN) and to derive a consensus on the interpretative algorithm. '0.7 of LLN for the $FEV_1$/FVC' was suggested by the COPD International Guideline (GOLD) for defining obstructive disease. A consensus on a new interpretative algorithm was recently achieved by ATS/ERS in 2005. We evaluated the accuracy of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases, and we also determined the effect of the new algorithm on diagnosing ventilatory defects. Methods: We obtained the age, gender, height, weight, $FEV_1$, FVC, and $FEV_1$/FVC from 7362 subjects who underwent spirometry in 2005 at the Asan Medical Center, Korea. For diagnosing obstructive diseases, the accuracy of '0.7 of LLN for the $FEV_1$/FVC' was evaluated in reference to the $5^{th}$ percentile of the LLN. By applying the new algorithm, we determined how many more subjects should have lung volumes testing performed. Evaluation of 1611 patients who had lung volumes testing performed as well as spirometry during the period showed how many more subjects were diagnosed with obstructive diseases according to the new algorithm. Results: 1) The sensitivity of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases increased according to age, but the specificity was decreased according to age; the positive predictive value decreased, but the negative predictive value increased. 2) By applying the new algorithm, 34.5% (2540/7362) more subjects should have lung volumes testing performed. 3) By applying the new algorithm, 13% (205/1611) more subjects were diagnosed with obstructive diseases; these subjects corresponded to 30% (205/681) of the subjects who had been diagnosed with restrictive diseases by the old interpretative algorithm. Conclusion: The sensitivity and specificity of '0.7 of LLN for the $FEV_1$/FVC' for diagnosing obstructive diseases changes according to age. By applying the new interpretative algorithm, it was shown that more subjects should have lung volumes testing performed, and there was a higher probability of being diagnosed with obstructive diseases.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.59-68
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• 2008

This study was carried out to investigate the effects of the Inside end-taping (Inside-ET) and Outside end-taping (Outside-ET) treatments on prevention of drying defects during radiofrequency/vacuum (RF/V) drying domestic yellow poplar log cross section with size of 20~75 mm in thickness and 120~470 mm in diameter. The treatments of Inside-ET and Outside-ET were quite effective for producing sound log cross sections with thinner than 33 mm and smaller than 270 mm in diameter. Even the 60 mm- and 75 mm-thick log cross sections, if the diameter was smaller than 30 cm, it might expect preventing formation of border checks by appropriate end-taping treatments. The positions of the observed border checks differed in diameter ranging at a relative radius about 0.50~0.63 diameter, and it was estimated that it was necessary to select the border position of end-taping treatment properly according to the diameter of log cross sections. It was observed that the radius of 0.3 diameter was the critical location for pretreatment for preventing formation of border checks in the log cross section with middle diameter. There were severe border checks and V-shaped cracks in the log cross section with large diameter. This was because of the severe variation of moisture content along radial direction of natural characteristic of domestic yellow poplar.

• Tribology and Lubricants
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• v.36 no.2
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• pp.105-115
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• 2020

This paper presents a numerical study on the rotordynamic analysis of a dual-spool turbofan engine in the context of blade defect events. The blades of an axial-type aeroengine are typically well aligned during the compressor and turbine stages. However, they are sometimes exposed to damage, partially or entirely, for several operational reasons, such as cracks due to foreign objects, burns from the combustion gas, and corrosion due to oxygen in the air. Herein, we designed a dual-spool rotor using the commercial 3D modeling software CATIA to simulate blade defects in the turbofan engine. We utilized the rotordynamic parameters to create two finite element Euler-Bernoulli beam models connected by means of an inter-rotor bearing. We then applied the unbalanced forces induced by the mass eccentricities of the blades to the following selected scenarios: 1) fully balanced, 2) crack in the low-pressure compressor (LPC) and high pressure compressor (HPC), 3) burn on the high-pressure turbine (HPT) and low pressure compressor, 4) corrosion of the LPC, and 5) corrosion of the HPC. Additionally, we obtained the transient and steady-state responses of the overall rotor nodes using the Runge-Kutta numerical integration method, and employed model reduction techniques such as component mode synthesis to enhance the computational efficiency of the process. The simulation results indicate that the high-vibration status of the rotor commences beyond 10,000 rpm, which is identified as the first critical speed of the lower speed rotor. Moreover, we monitored the unbalanced stages near the inter-rotor bearing, which prominently influences the overall rotordynamic status, and the corrosion of the HPC to prevent further instability. The high-speed range operation (>13,000 rpm) coupled with HPC/HPT blade defects possibly presents a rotor-case contact problem that can lead to catastrophic failure.

• Journal of Life Science
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• v.19 no.3
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• pp.317-321
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• 2009

Down syndrome (DS) results from overexpressed genes on an extra copy of human chromosome 21. Among various phenotypes seen in DS patients, mental retardation, such as learning and memory deficits, is a major factor that prevents DS individuals from leading fully independent lives. The Dyrk1A gene that plays a critical role in neurodevelopment has been isolated from chromosome 21, and transgenic mice with over-expression of Dyrk1A show severe hippocampal dependent learning and memory defects. In the present study, as an initial step to test the treatment of Dyrk1A dependent mental retardation phenotypes in model animals, we isolated human Dyrk1A specific lentiviral short hairpin RNA (shRNA) that inhibits the exogenous human Dyrk1A expression, but not the endogenous mouse expression in transgenic mice with human Dyrk1A overexpression. This limited and specific repression of exogenous human Dyrk1A will prove to be valuable information, if Dyrk1A dependent learning and memory defects in DS patients could be treated or at least ameliorated in vivo.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.220-229
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• 2008

Purpose: The present study was aimed to examine the effect of acellular dermal matrix ($AlloDerm^{(R)}$) grafted to the experimental tissue defect on tissue regeneration. Materials and Methods: Male albino rabbits were used. Soft tissue defects were prepared in the external abdominal oblique muscle. The animals were then divided into 3 groups by the graft material used: no graft, autogenous dermis graft, and $AlloDerm^{(R)}$ graft. The healing sites were histologically examined at weeks 4 and 8 after the graft. In another series, critical sized defects with 8-mm diameter were prepared in the right and left iliac bones. The animals were then divided into 5 groups: no graft, grafted with autogenous iliac bone, $AlloDerm^{(R)}$ graft, $AlloDerm^{(R)}$ graft impregnated with rhBMP-2, and $AlloDerm^{(R)}$ graft with rhTGF-${\beta}1$. The healing sites of bone defect were investigated with radiologic densitometry and histological evaluation at weeks 4 and 8 after the graft. Results: In the soft tissue defect, normal healing was seen in the group of no graft. Inflammatory cells and foreign body reactions were observed in the group of autogenous dermis graft, and the migration of fibroblasts and the formation of vessels into the collagen fibers were observed in the group of $AlloDerm^{(R)}$ graft. In the bone defect, the site of bone defect was healed by fibrous tissues in the group of no graft. The marked radiopacity and good regeneration were seen in the group of autogenous bone graft. There remained the traces of $AlloDerm^{(R)}$ with no satisfactory results in the group of $AlloDerm^{(R)}$ graft. In the groups of the $AlloDerm^{(R)}$ graft with rhBMP-2 or rhTGF-${\beta}1$, there were numerous osteoblasts in the boundary of the adjacent bone which was closely approximated to the $AlloDerm^{(R)}$ with regeneration features. However, the fibrous capsule also remained as in the group of $AlloDerm^{(R)}$ graft, which separated the $AlloDerm^{(R)}$ and the adjacent bone. Conclusions: These results suggest that $AlloDerm^{(R)}$ can be useful to substitute the autogenous dermis in the soft tissue defect. However, it may not be useful as a bone graft material or a carrier, since the bone defect was not completely healed by the bony tissue, regardless of the presence of osteogenic factors like rhBMP-2 or rhTGF-${\beta}1$.

• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.11-18
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• 2011

The periosteum contains multipotent cells that can differentiate into osteoblasts and chondrocytes. Cultured periosteum-derived cells (PDCs) have an osteogenic capacity. The purpose of this study was to evaluate the interaction of PDCs with bone graft biomaterial. After cell isolation from the calvarial periosteum of Sprague-Dawley rats, cultured PDCs were placed in critical-sized calvarial defects with beta-tricalcium phosphate (${\beta}$-TCP). All rats were sacrificed 8 weeks after bone graft surgery, and the bone regenerative ability of bone grafting sides was evaluated by plain radiography, micro-computed tomography (CT), and histological examination. PDCs grafted with ${\beta}$-TCP displayed enhanced calcification in the defect site, density of regenerated bone and new bone formation within the defect and its boundaries. Furthermore, these PDCs more efficiently regenerated new bone as compared to grafted ${\beta}$-TCP only. The results suggest that cultured PDCs have the potential to promote osteogenesis in bone defects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.114-120
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• 2007

The augmentation of soft tissue defects is one of the critical problems in the oral and maxillofacial surgery. Various types of graft materials, both autologous and non-autologous, have been used for the augmentation of soft tissue in the facial region. However, it is not easy to choose an ideal material for soft tissue augmentation because each has its advantages and disadvantages. An ideal graft material should meet the following criteria : it should not leave a scar at the area from which it was taken; should have less likelihood of causing infection; should feel natural after implanted; and should be not absorbed. Among the materials meeting these criteria, human dermis and artificial dermis are commonly used for clinical purposes. The present study was aimed to investigate and compare the resorption rate and the histological change following the use of the autologous dermis, the human homogenous dermis $Alloderm^{(R)}$, and the artificial dermis $Terudermis^{(R)}$ to reconstruct the soft tissue defect. Twenty mature rabbits of either sex, weighing about 2 ㎏, were used. Each rabbit was transplanted with the autologous dermis, $Alloderm^{(R)}$, and $Terudermis^{(R)}$ size $1{\times}1-cm$ at the space between the external abdominal oblique muscle and the external abdominal oblique fascia. They were then divided into 4 groups (n=5 each) according to the time elapsed after the surgery: 1, 2, 4, and 8 weeks. The resorption rate was calculated by measuring the volume change before and after the transplantation, and H-E stain was preformed to observe the histological changes. The resorption rate after 8 weeks was 21.5% for the autologous dermis, 16.0% $Alloderm^{(R)}$, and 36.4% $Terudermis^{(R)}$, suggesting that $Alloderm^{(R)}$ is the most stable while $Terudermis^{(R)}$ is the most unstable. In microscopic examinations, the autologous dermis graft was surrounded by inflammatory cells and showed foreign body reactions. The epidermal inclusion cyst was observed in the autologous dermis graft. $Terudermis^{(R)}$ and $Alloderm^{(R)}$ demonstrated neovascularization and the progressive growth of new fibroblast. The results suggest that $Terudermis^{(R)}$ and $Alloderm^{(R)}$ can be availably for substituting the autologous dermis.

• Journal of Periodontal and Implant Science
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• v.41 no.4
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• pp.176-184
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• 2011

Purpose: The final goal of regenerative periodontal therapy is to restore the structure and function of the periodontium destroyed or lost due to periodontitis. However, the role of periosteum in periodontal regeneration was relatively neglected while bone repair in the skeleton occurs as a result of a significant contribution from the periosteum. The aim of this study is to understand the histological characteristics of periosteum and compare the native periosteum with the repaired periosteum after elevating flap or after surgical intervention with flap elevation. Methods: Buccal and lingual mucoperiosteal flaps were reflected to surgically create critical-size, "box-type" (4 mm width, 5 mm depth), one-wall, intrabony defects at the distal aspect of the 2nd and the mesial aspect of the 4th mandibular premolars in the right and left jaw quadrants. Animals were sacrificed after 24 weeks. Results: The results from this study are as follows: 1) thickness of periosteum showed difference as follows (P<0.05): control group ($0.45{\pm}0.22$ mm)> flap-elevation group ($0.36{\pm}0.07$ mm)> defect formation group ($0.26{\pm}0.03$ mm), 2) thickness of gingival tissue showed difference as follows (P<0.05): defect formation group ($3.15{\pm}0.40$ mm)> flap-elevation group ($2.02{\pm}0.25$ mm) > control group ($1.88{\pm}0.27$ mm), 3) higher cellular activity was observed in defect formation group and flap-elevation groups than control group, 4) the number of blood vessles was higher in defect formation group than control group. Conclusions: In conclusion, prolonged operation with increased surgical trauma seems to decrease the thickness of repaired periosteum and increase the thickness of gingiva. More blood vessles and high cellular activity were observed in defect formation group.