• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.897-904
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• 2022

The purpose of this study is to compare the difference in dose and image quality when applying the diagnostic reference level (DRL) test conditions for head radiography in a digital radiation environment and the test conditions currently applied in clinical practice. I would like to review the conditions of radiographic examination. In this study, the head model phantom was targeted, and the investigation conditions were divided into clinical conditions (Clinic), DRL value (DRL₇₅), and DRL average value (DRL_mean). For dose, Enterance surface dose (ESD) was measured, and for image quality, signal-to-noise ratio and contrast-to-noise ratio were measured and analyzed for comparison. The average values of skull anterior posterior(AP) ESD according to the changes in test conditions were Clinic 1214.03±4.21 µGy, DRL₇₅ 3017.83±8.14 µGy, DRL_mean 2283.50±7.09 µGy, and skull lateral (Lat). The average value of ESD was statistically significant with Clinic 762.79±3.54 µGy, DRL₇₅ 2168.57±10.83 µGy, and DRL_mean 1654.43±6.48 µGy (p<0.01). The average values of SNR and CNR measured in the orbital, maxillary sinus, frontal sinus, and sella turcica were statistically significant (p<0.01). As a result of this study, compared to DRL, the conditions used in clinical practice showed lower dose levels of about 58% for AP and about 70% for Lat., and there was no qualitative difference in terms of image quality. Through this study, it is necessary to consider a new diagnostic reference level suitable for the digital radiation environment, and it is considered that the dose should be reduced accordingly.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.41-50
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• 2008

The histochemical characteristics and ultrastructure of the mantle in the spiny top shell, Batillus cornutus were described using light and electron microscopy. The simple epidermal layer wrapped on the top and bottom of the centrally located connective tissue. And then the epidermal layer were divided into the outer epidermal layer near a shell and the inner epidermal layer closed to the visceral mass. The connective tissue layer was composed of the collagen fiber muscularfiber bundle and hemolymph sinus. Mucous cells in the apical mantle contained acid and neutral mucopolysaccaride, and acidic carboxylated mucopolysaccaride in the mid and marginal mantle. The mantle thickness, epidermal layer thickness and hemolymph sinus area displayed a trend of reduction from the marginal zone to the apical zone. From TEM observation, it was possible to distinguish epithelium, ciliated cell, absorptive cell and secretory cell in the epidermal layer. The epithelia were columnar and the nucleus was elliptical. The free surface were covered with microvilli. The lateral membranes of epithelium was con nected with neighboring cells by the zonular occludens, zonular adherens and membrane interdigitation. Ciliated cell on free surface had cilia and microvilli, and numerous mitochondria in the apical cytoplasm. In the epidermal layer, it observed 2 type cells having absorptive function. The absorptive cells were columnar in shape, and contained microvilli, pinocytotic vesicles, mitochondria and lysosomes of various electron density. Secretory cells can be divided into four types (A, B, C, D) depending on the cell shape and characteristics of secretory granules. These cells were unicellular glands and had similar characteristics to previously reported on the mantle of the gastropod and bivalves.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.424-434
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• 2009

Statement of problem: Problems such as loosening and fractures of retained screws and fracture of implant fixture have been frequently reported in implant prosthesis. Purpose: Implant has weak mechanical properties against lateral loading compared to vertical occlusal loading, and therefore, stress analysis of implant fixture depending on its material and geometric features is needed. Material and methods: Total 28 of external hexed implants were divided into 7 of 4 groups; Group A (3i, FULL $OSSEOTITE^{(R)}$Implant), Group B (Nobelbiocare, $Br{\aa}nemark$ $System^{(R)}$Mk III Groovy RP), Group C (Neobiotec, $SinusQuick^{TM}$ EB), Group D (Osstem, US-II). The type III gold alloy prostheses were fabricated using adequate UCLA gold abutments. Fixture, abutment screw, and abutment were connected and cross-sectioned vertically. Hardness test was conducted using MXT-$\alpha$. For fatigue fracture test, with MTS 810, the specimens were loaded to the extent of 60-600 N until fracture occurred. The fracture pattern of abutment screw and fixture was observed under scanning electron microscope. A comparative study of stress distribution and fracture area of abutment screw and fixture was carried out through finite element analysis Results: 1. In Vicker's hardness test of abutment screw, the highest value was measured in group A and lowest value was measured in group D. 2. In all implant groups, implant fixture fractures occurred mainly at the 3-4th fixture thread valley where tensile stress was concentrated. When the fatigue life was compared, significant difference was found between the group A, B, C and D (P<.05). 3. The fracture patterns of group B and group D showed complex failure type, a fracture behavior including transverse and longitudinal failure patterns in both fixture and abutment screw. In Group A and C, however, the transverse failure of fixture was only observed. 4. The finite element analysis infers that a fatigue crack started at the fixture surface. Conclusion: The maximum tensile stress was found in the implant fixture at the level of cortical bone. The fatigue fracture occurred when the dead space of implant fixture coincides with jig surface where the maximum tensile stress was generated. To increase implant durability, prevention of surrounding bone resorption is important. However, if the bone resorption progresses to the level of dead space, the frequency of implant fracture would increase. Thus, proper management is needed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.368-375
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• 2013

Purpose: This study is to evaluate the location of descending palatine artery, the anatomy of pterygomaxillary junction, and the association between the obtained anatomic values and several variables. Methods: We studied 40 patients who were treated for dentofacial deformites from January 2010 to December 2012 in Ulsan University Hospital, Ulsan, Korea. Cone beam computed tomogram (CBCT) was done for all patients. The reference point was approximately 5 to 7 mm above anterior nasal spine on axial image. We evaluated the location of the greater palatine canal (line a: on the coronal view, the shortest line between the center of greater palatine canal and pterygoid fossa; distance a: the distance of line a). We also measured the thickness (line b: on the coronal view, the shortest line between maxillary posterior sinus wall and pterygoid fossa; distance b: distance of line b), width (line c: on the coronal view, the line perpendicular to the line b and the nearest line from the most concave point of lateral pterygoid plate to the medial pterygoid plate; distance c: distance of line c) and height (line d: on sagittal view, the vertically longest line of pterygoid junction; distance d: the distance of line d) in pterygomaxillary junctions. We evaluated the association between the obtained anatomic values and several variables (sex, age, height and weight). Results: The mean distance a was 4.78 mm, mean distance b was 5.53 mm, mean distance c was 8.01 mm and mean distance d was 13.22 mm. The differences between age and mean distance c and weight and mean distance d in pterygomaxillary junctions are statistically significant. Conclusion: There apparently is anatomic variation of pterygomaxillary junctions by various values, particularly weight and age in a Korean clinical population.

• Applied Microscopy
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• v.33 no.3
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• pp.223-231
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• 2003

Histology and ultrastructure of the gill in the granular ark, Tegillarca granosa are described using light and transmission electron microscopy. The gill of the clam have typical structure of the filibranch type. The gill filament have several band of lateral and apical cilia. The epithelial layer surrounding the hemolymph sinus is simple and consists of epithelial cells, ciliated cells and secretory cells. The epithelial cells are usually squamous and covered with microvilli. The ciliated cells are usually columnar and can be divided into two types (A and B). Type A cells are more abundance and have lower electron density than B cells. Ultrastructure of the cilia showed that '9+2' microtubular structure of the axial filament and '$2{\times}9$' proximal centriole structure in the cross section. Secretory cells are mainly observed in the apical region of the filament and can be divided into three types of A, B and C with morphological features of the secretory granules. Type A cells of oval shaped are more abundance than other secretory cells and contains numerous secretory granules of low electron dense. Type B cells contains secretory granules of membrane-bounded and high electron dense. Secretory granules of type C cells are elliptical and fine granules surrounding the homogeneous core materials.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.181-190
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• 2011

This study was investigated to find out the change of reproductive and histological biomarkers of Ruditapes philippinarum exposed to nonylphenol (NP). Experimental period was 16 weeks. Experimental groups were composed of one control condition and three NP exposure conditions (0.05, 0.1, $0.2 mg\;NP\;L^{-1}$). Gonad index was higher in exposure group than control in female and higher in control than exposure group in male. Intersexuality in the NP exposure group was 14.56% with male exhibiting higher ratio than female. Histological analysis of organ system illustrated expansion of hemolymph sinus, loss of striated border of inner epidermis and degeneration of mucous cell in the mantle. In the gill partially disappearance of frontal and lateral cilia, degeneration of mucous cell were observed. Also, hyperplasia of epithelium and disappearance of striated border were observed in the foot. As the concentration of NP increased, the accumulation of lipofuscin increased in the digestive gland. The results of this study suggest that NP induces reduction of survival rate, histopathology and intersex of R. philippinarum. Furthermore, it is indentified that NP functions as an estrogenic effector on the reproduction of R. philippinarum.

• Pediatric Infection and Vaccine
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• v.21 no.2
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• pp.144-149
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• 2014

Acute otitis media (AOM) is one of the most common childhood infectious diseases. Despite antibiotic treatment for AOM, AOM and its complication still continue to develop. Acute mastoiditis is a serious complication of AOM and epidural abscess constitutes the commonest of all intracranial complication of AOM. Neurological complication of acute mastoiditis are rare but can be life threatening. Their presentation may be masked by the use of antibiotics. We report the rare case of acute otitis media progressing to acute mastoiditis, epidural abscess formation and lateral sinus thrombophlebitis caused by Streptococcus pneumoniae in a child. She was admitted with acute otitis media with fever. Despite proper antibiotics, acute mastodititis and epidural abscess were developed, and after surgical drainage and antibiotics therapy she was recovered without sequalae.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.61-71
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• 2009

Anchorage control is important in orthodontic treatment. Recently miniscrew is widly used as maximum anchorage in orthodontic treatment, and then it is important to install miniscrew safely without damaging adjacent anatomic structure. In a view of Miniscrew's stability, maxilla is unfavorable than mandible, and moreover maxillary soft buccal bone has disadvantage on stability. so palatal area comes into notice for installation area. We measured distance between palatal roots and bone thickness at midpalatal area using 3D computed tomography, and have found following results. 1. On the comparison of distance between palatal roots, the distance between 2nd premolar and 1st molar was significantly longest and the distance between premolars was significantly shortest. 2. Going toward lateral area from midpalatal suture and posterior area from zero point, bone thickness significantly became shorter and shorter. And 5.0mm palatal sagittal plane has more significance decrease of bone thickness than 2.5mm palatal sagittal plane. According to these results, we can conclude that the palatal installation of miniscrew between 2nd premolar and 1st molar is safest. And it is more safe that comes closer to midpalatal suture and to anterior area in regard to incisive canal.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.805-824
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• 2007

Purpose: Developments in micro/macrostructures of implants and surgical techniques brought out stable outcomes of implant dentistry. The aim of this study was to evaluate the distributions of implant patients, the types of implanted sites, and the success or survival rates of various implant systems and to analyze the implant placement done at each specificintraoral site and situation. Materials and Methods: The data of dental implantations collected between 1992 and 2006 at the Department of Periodontology in 00000 University Hospital were analyzed. Results: 1. Largest part of the patients were at the age of 40s and 50s in bothgender who lost their teeth mostly by periodontaldiseases and caries at the posterior intraoral sites as major ones. Bone densities of type II(mandible) and III(maxilla) were likely to be seen with quantity of type B. Lengths of the implants between 10 and 15 mm and wide platform took the largest part. 2. Survival rates of $Implantium^{(R)}(98.8%)$, $Xive^{(R)}(100%)$ and ITI $TE^{(R)}(100%)$ were high when $Frialit-2^{(R)}$ showed 82%(poor bone density area) or 87.2%(combined with additional therapy). $IMZ^{(R)}$ had lowest cumulative survival(67.5%) and success rate(49.4%) amongst all. 3. Replacement with 2 wide or 3 regular platforms showed no significant differences in survival rate and marginal bone loss atmandibular posterior area. In single restoration of mandibular second molar, 5-year success rate of machined surface $Br{\aa}nemark^{(R)}(70.37%)$ was lower than that of rough surface $ITI^{(R)}$ SLA(100%). 4. Replacement of single tooth in anterior area showed high survival rate of 94.5%. 5. The success rates of $Br{\aa}nemark$ Ti-Unite and ITI SLA at posterior maxilla with poor bone density both showed stable outcomes. 6. 10-year cumulative survival rate of implants with maxillary sinus augmentation by lateral window approach appeared to be 96.60%. Low survival rate(75%) was shown when there were more than two complications combined. Height of grafted bone remained stable above the implant apex. Conclusions : Rough surfaced implants showed stable outcomes in most of the situation including poor bone density and additional therapy combined.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.457-462
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• 2003

Background: Surgical results of the Fontan procedures in patients with a single ventricle have improved. As the perioperative mortality continues to decline and late outcome is forthcoming, attention is now being directed toward late complications of the Fontan procedures. We retrospectively analyzed our experience with reoperations after Fontan procedures. Material and Method: Between January 1988 and December 2002, 24 patients underwent reoperations after Fontan procedures. The median age at Fontan procedures and reoperation was 3.3 years and 9.2 years, respectively. Types of initial Fontan procedures were atriopulmonary connection (n＝11), lateral tunnel Fontan (n＝11), and extracardiac conduit Fontan (n＝2). Indications for reoperation included atrioventricular valve regurgitation (n＝7), atrial arrhythmia (n＝8), Fontan pathway stenosis (n＝7), residual right-to-left shunt (n＝5), etc. Result: Procedures performed at reoperation included atrioventricular valve replacement (n＝6), conversion to lateral tunnel Fontan (n＝5), conversion to extracardiac conduit Fontan (n＝3), cryoablation of arrhythmia circuit (n＝7), etc. There was no operative mortality. There were 2 late deaths. Mean follow-up duration was 2.7$\pm$2.1 years. All patients except two were in NYHA class I at the latest follow-up. Among 8 patients with preoperative atrial arrhythmia, postoperative conversion to normal sinus rhythm was achieved in 7 patients. Conclusion: Reoperations after Fontan procedures could be achieved with low mortality and morbidity. Reoperation may lead to clinical improvement in patients with specific target conditions such as atrioventricular valve regurgitation, refractory atrial arrhythmia, or Fontan pathway stenosis, especially in patients with previous atriopulmonary connection.