• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.57-64
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• 2017

Today, due to the environmental regulations regarding air pollution in the EU, the use of EPS (Styrofoam) as the cushioning material in the packaging industry is decreasing. In effect, air cushioning based cushioning materials are rapidly expanding into the market and replacing EPS, due to their excellent buffering ability and environmental friendliness. This is a new selective filling type air filling material manufacturing technology that affords improvements in the amount of raw materials required, its processing and its aesthetic appearance compared to the conventional air filling cushioning materials. In this study, a multi-stage air cell filling valve molding technology is developed based on selective filling technology, which allows packages to be selectively filled in various forms by applying valve forming structure technology. This multi-stage air cell filling valve molding technology is a technique in which a plurality of injection ports are formed by laminating three layers of films, viz. a first injection film, a valve film, and a second injection film having valve ends. In the conventional technology, a separate external air injection path for injecting air into a plurality of connected air bags is needed. However, in the proposed system, an external air injection path is formed inside the air bag, Due to the lack of need for an injection furnace, the raw material and process are reduced and air is injected and then discharged, while the air bag is reduced in length to 63 ~ 66% of its normal value. The outer surface of the outer air injection path is integrated inside by maintaining the original length of the cross section, while the unnecessary folded air is injected into the interior of the air bag, This smart air filling type cushioning material manufacturing technology constitutes a big improvement over the existing technologies.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.413-420
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• 2011

Garre's osteomyelitis is associated with bacterial infection and bone necrosis resulting from obstruction of blood supply. The most common cause for Garre's osteomyelitis is odontogenic infection that originates from periodontal tissue or dental pulp. Subperiosteal abscess may also cause Garre's osteomyelitis in the progress of the infection. Mandible is more often affected than maxilla, most commonly in the permanent first molar region of mandible. Clinically, it results in a hard swelling over the jaw, producing facial asymmetry. Meanwhile, radiograph shows a characteristic feature of irregular pulpal cavity, showing new periosteal proliferation located in successive layers to the condensed cortical bone on stimulated site. The treatment method for Garre's osteomyelitis are removal of the infection source, root canal treatment, antibiotic medication, and incision and drainage. This report presents a case of Garre's osteomyelitis under 15 years old. The patient was successfully treated by antibiotic medication accompanied with root canal treatment. Since the symptom of pediatric patients is less severe than adult, careful diagnosis with history taking and clinical examination is necessary. Furthermore long-term follow-up examination is needed to prevent recurrence even after the symptom disapears.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.135-140
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• 1998

Drag reduction produced by dilute solution of water soluble ionic polymer-surfactant complex under turbulent flow in a rotating disk apparatus(RDA) was investigated in this study. Three different molecular weights of polyacrylic acid(PAA) were adopted as drag reducing additives, and distilled water was used as a solvent. Experiments were undertaken to observe the dependence of drag reduction on various factors such as polymer molecular weight, molecular expansions and flexibility, rotating speed of the disk and polymer concentration. Specific considerations were put on conformational difference between surfactant and polymer, and effect of pH on ionic polymer possessing various molecular conformation through pH. The complex of ionic polymer and surfactant(Sodium Dodecyl Sulfate) behaves like a large polyelectrolyte. Surfactant changes the polymer conformation and then increases the dimension of the polymer. The radius of gyration, hydrodynamic volume and relative viscosity of the polymer-surfactant system are observed to be greater than those of polymer itself. Such surfactant-polymer complex has enhanced drag reduction properties.

• Anatomy & Biological Anthropology
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• v.31 no.4
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• pp.133-142
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• 2018

3D histology is a imaging system for the 3D structural information of cells or tissues. The synchrotron radiation propagation phase contrast micro-CT has been used in 3D imaging methods. However, the simple phase contrast micro-CT did not give sufficient micro-structural information when the specimen contains soft elements, as is the case with many biomedical tissue samples. The purpose of this study is to develop a new technique to enhance the phase contrast effect for soft tissue imaging. Experiments were performed at the imaging beam lines of Pohang Accelerator Laboratory (PAL). The biomedical tissue samples under frozen state was mounted on a computer-controlled precision stage and rotated in $0.18^{\circ}$ increments through $180^{\circ}$. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens(X5 or X20) before being captured with a digital CCD camera. 3-dimensional volume images of the specimen were obtained by applying a filtered back-projection algorithm to the projection images using a software package OCTOPUS. Surface reconstruction and volume segmentation and rendering were performed were performed using Amira software. In this study, We found that synchrotron phase contrast imaging of frozen tissue samples has higher contrast power for soft tissue than that of non-frozen samples. In conclusion, synchrotron radiation propagation phase contrast cryo-microCT imaging offers a promising tool for non-destructive high resolution 3D histology.

• Pediatric Infection and Vaccine
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• v.10 no.1
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• pp.102-113
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• 2003

Purpose : Acute respiratory tract infections are the most common illnesses in children. The great majority of these infections involving lower respiratory tracts infections(LRTI) are caused by respiratory viruses such as respiratory syncytial virus(RSV), parainfluenza virus (PIV), influenza virus(INF), adenovirus(ADV), etc. Our purpose of this study was to examine the seasonal occurrence, clinical and laboratory features of each viral infections. Methods : Nasopharyngeal aspirates(NPA) were collected from 913 hospitalized children on the first day of admission. They were all admitted to Hangang Sacred Heart hospital and diagnosed as LRTIs. The study period was from September 1998 to August 2002. Specimens were inoculated onto HEp-2 cell, LLC-MK2 cell and MDCK cell. Viruses were detected by immunofluorescent method performed at day 10 postinoculation. Respiratory viruses were detected in 251(27%) cases. Medical records of 208 cases diagnosed as acute LRTIs were all taken reviewed and analyzed. Results : The identified pathogens were RSV 122 cases(58%), PIV 30 cases(14%), INFA 20 cases(10%), INFB 21 cases(11%) and ADV 15 cases(7%) during the study period. Outbreaks of RSV infections occurred every year but mostly on December, 1998 and November, 1999. LRTIs by PIV and ADV occurred during all seasons of the year. INFA was isolated moslty on March, 1999 and January, 2000. INFB infections occurred largely on April, 2002. The clinical diagnoses were bronchiolitis 88 cases(43%), pneumonia 87 cases(42%), croup 19 cases(9%) and tracheobronchitis 14 cases(6%). Common symptoms and signs were cough, rhinorrhea, sputum and fever. WBC counts in peripheral blood showed normal findings in 123 cases(59%). Each viral infections also showed some differences in auscultatory findings and chest X-ray findings. Conclusion : We learned that viruses are one of the major and important etiologic agents of acute LRTIs of children in Korea. However, we still need to find out more about its characteristic clinical features and continue studying on their seasonal occurrence to focus on their management and also prevention.