• Journal of the Society of Naval Architects of Korea
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• v.53 no.3
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• pp.180-187
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• 2016

As distinct from a slender body, the separation of the boundary layer on a bluff body give rise to complex wakes in which various kinds of vortices form, develop and interact with each other. In this paper, we investigate cavitation wake field behind wedge shaped two-dimensional fin models. Eight different models are tested at the Chungnam National University Cavitation Tunnel (CNU-CT). First, we measure wake cavity shapes and compare with numerical results, which shows the good agreement with each other. In addition, we demonstrate that wake flow characteristics of the control fin are clearly identified by the correlation analysis of high-speed camera images and pressure fluctuation measurements.

• Journal of Oral Medicine and Pain
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• v.23 no.3
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• pp.271-276
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• 1998

The purpose of the pilot study was to know the relationship between halitosis and oral hygine, to examine the difference of the positon of the straw to be placed in the oral cavity by using Halimeter. Fourteen persons that has good health condition without halitosis were participated in this pilot study. They were treated twice prophylaxis and then they had not tooth brushing during two weeks. After two weeks, they were examied to gingival index, plaque index, VSC valuses. The obtained results were as follosws : 1. No significant difference of VSC values were observed during two weeks withoiut tooth brushing. But significant difference of gingival index, plaque index were observed. It was suggested that halitosis was not caused by only plaque, complex reasons(salivary function, stress etc) maybe caused halitosis. 2. Here were significant reduction of VSC values as the depth of plastic straw into the oral cavity decreased (p<0.05)

• Journal of Photoscience
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• v.3 no.3
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• pp.153-158
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• 1996

The effects of $\alpha$- and $\beta$-cyclodextrins (CD) on the twisted intramolecular charge transfer (TICT) behavior of p-N,N'-dimethylaminobenzoic acid (DMABA) in buffered aqueous solution have been investigated by examining formation and decay behaviors of the TICT-typical dual fluorescence. The ratio of the TICT emission to the normal emission (I$_a$/I$_b$) increases linearly $\alpha$-CD concentration increases, while in the presence of $\beta$-CD it shows nonlinear dependences on the CD concentration. The analysis of the CD-dependent changes of the I$_a$/I$_b$ and absorption spectra demonstrates formation of 1:1 inclusion complexes between DMABA and CDs. The decay time of the normal emission (ca. 700 ps) is little affected by the formation of $\alpha$-CD inclusion complex, whereas it increases upto ca. 1.6 ns upon formation of $\beta$-CD inclusion complex. The TICT emission for the $\beta$-CD inclusion complex exhibits two decay components while it shows a single component for the $\alpha$-CD inclusion complex, indicating formation of one or two types of inclusion complex in the presence of $\alpha$-CD or $\beta$-CD, respectively. These results are attributed to the CD cavity size dependence on patterns of complexation between CDs and DMABA. The CD size dependences of the TICT fluorescence properties with the orientation of the guest molecule demonstrate that the specific hydrogen bonding between the carboxylic acid group and water plays an important role in the excited-state TICT.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.128-135
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• 2020

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body and causes skin and soft tissue infections (SSTI). The present study examined the antimicrobial resistance patterns and molecular epidemiological characteristics of MRSA isolated from nasal swabs in clinical patients. SCCmec type of MRSA isolates from clinical patients were analyzed: 24 cases were SCCmec type-II; two cases were type-II/IVa; one case was type-II/V; one case was type-IVa; 11 cases were not-typeable. The mec complex type of MRSA isolates from clinical patients were analyzed: 29 cases were mec complex type A, and 10 cases were not-typeable, but type B was not found in the present study. In conclusion, SCCmec type-II and mec complex type A were the most dominant MRSA subtypes among the MRSA isolates from a nasal swab of patients, and the results were similar to other studies on hospital-acquired MRSA (HA-MRSA). These results can not only provide basic data for hospital infection management but also be a good guideline for MRSA infections in the Republic of Korea.

• International Journal of Oral Biology
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• v.48 no.2
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• pp.9-18
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• 2023

The rapid detection of bacteria in the oral cavity, its species identification, and bacterial count determination are important to diagnose oral diseases caused by pathogenic bacteria. The existing clinical microbial diagnosis methods are time-consuming as they involve observing patients' samples under a microscope or culturing and confirming bacteria using polymerase chain reaction (PCR) kits, making the process complex. Therefore, it is required to analyze the development status of substances and systems that can rapidly detect and analyze pathogenic microorganisms in the oral cavity. With research advancements, a close relationship between oral and systemic diseases has been identified, making it crucial to identify the changes in the oral cavity bacterial composition. Additionally, an early and accurate diagnosis is essential for better prognosis in periodontal disease. However, most periodontal disease-causing pathogens are anaerobic bacteria, which are difficult to identify using conventional bacterial culture methods. Further, the existing PCR method takes a long time to detect and involves complicated stages. Therefore, to address these challenges, the concept of point-of-care (PoC) has emerged, leading to the study and implementation of various chair-side test methods. This study aims to investigate the different PoC diagnostic methods introduced thus far for identifying pathogenic microorganisms in the oral cavity. These are classified into three categories: 1) microbiological tests, 2) microchemical tests, and 3) genetic tests. The microbiological tests are used to determine the presence or absence of representative causative bacteria of periodontal diseases, such as A. actinomycetemcomitans, P. gingivalis, P. intermedia, and T. denticola. However, the quantitative analysis remains impossible, and detecting pathogens other than the specific ones is challenging. The microchemical tests determine the activity of inflammation or disease by measuring the levels of biomarkers present in the oral cavity. Although this diagnostic method is based on increase in the specific biomarkers proportional to inflammation or disease progression in the oral cavity, its commercialization is limited due to low sensitivity and specificity. The genetic tests are based on the concept that differences in disease vulnerability and treatment response are caused by the patient's DNA predisposition. Specifically, the IL-1 gene is used in such tests. PoC diagnostic methods developed to date serve as supplementary diagnostic methods and tools for patient education, in addition to existing diagnostic methods, although they have limitations in diagnosing oral diseases alone. Research on various PoC test methods that can analyze and manage the oral cavity bacterial composition is expected to become more active, aligning with the shift from treatment-oriented to prevention-oriented approaches in healthcare.

• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.305-310
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• 2008

A 10-year-old female Yorkshire terrier with the clinical signs of nasal swelling, epistaxis and nasal discharge was presented to the Veterinary Teaching Hospital in the Cheju National University. Abnormal nasal mass was detected in physical examination and radiographic findings. After surgical excision, the sample of nasal mass was referred to Pathology Department of Veterinary Medicine. Grossly, the mass was soft, friable, and $2.5{\times}4cm$ cm in size. Histopathologically, the mass was composed of mediumsized non-keratinizing columnar to polyhedral cells arranged in anastomosing ribbon and large nest. It has complex in-folding of thick epithelial layers separated by fibrovascular septa. Tumor cells showed characteristic palisading arrangement of columnar cells, and perpendicularly distributed to the basement membrane. The cells had pale basophilic cytoplasm, oval nucleus and one or more nucleoli, and indistinct cellular border. Many tumor cell emboli were presented in lymphatics. Immunohistochemistry revealed that tumor cells were cytokeratin (CK) 19 and CK clone MNF116 positive and but CK7 and CK high molecular weight negative. Based on the gross, histopathologic, and immunohistochemical findings, the mass was diagnosed as transitional carcinoma in nasal cavity. In our best knowledge, this is the first report of transitional carcinoma originated from transitional zone of canine nasal cavity in Korea.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.26-32
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• 2007

A simple but accurate equivalent circuit of an aperture-coupled cavity-fed microstrip patch antenna is developed. It consists of ideal transformers, admittance elements, and transmission lines, and the related circuit element values are computed by applying the reciprocity theorem and complex power concept with the spectral-domain immittance approach. After validating by the published design example, a dual-band antenna was designed with the help of a hybrid optimization method. For this purpose, the Genetic Algorithm is applied with the Nelder-Mead simplex method. The obtained good results show that this approach turned out to be a very efficient tool for the design of aperture-coupled cavity-fed microstrip patch antenna having various structural design parameters.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.919-929
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• 2014

In recent, the requirements for the safety to the effects of high power electromagnetic wave have been increased along with the development of electricity and electronic equipments. The small sized electronic devices and the various components have been analyzed by using the full-EM simulation and solving a complete set of Maxwell equation. However, the deterministic approach has a drawback and much limitation in the electromagnetic analysis of an electrically large cavity with a high complexity of the structure. In this paper, statistical theory and topological modeling method are combined to analyze the large cavity with a complex structure. In particular, the PWB(Power Balance) method and BLT(Baum-Liu-Tesche) equation are combined and employed to solve the frequency response to the large-scaled cavity with remarkably reduced time-consumption. For instance, a PCB substrate inside box of box are considered as a large structure with a complexity.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.123-130
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• 2019

Chelatase catalyzes the insertion of divalent metal into tetrapyrrole and plays a key role in the biosynthesis of metallated tetrapyrroles, such as cobalamin, siroheme, heme, and chlorophyll. SirB is a sirohydrochlorin (SHC) chelatase that generates cobalt-SHC or iron-SHC by inserting cobalt or iron into the center of sirohydrochlorin tetrapyrrole. To provide structural insights into the metal-binding and SHC-recognition mechanisms of SirB, we determined the crystal structure of SirB from Bacillus subtilis subsp. spizizenii (bssSirB) in complex with cobalt ions. bssSirB forms a monomeric ${\alpha}/{\beta}$ structure that consists of two domains, an N-terminal domain (NTD) and a C-terminal domain (CTD). The NTD and CTD of bssSirB adopt similar structures with a four-stranded ${\beta}-sheet$ that is decorated by ${\alpha}-helices$. bssSirB presents a highly conserved cavity that is generated between the NTD and CTD and interacts with a cobalt ion on top of the cavity using two histidine residues of the NTD. Moreover, our comparative structural analysis suggests that bssSirB would accommodate an SHC molecule into the interdomain cavity. Based on these structural findings, we propose that the cavity of bssSirB functions as the active site where cobalt insertion into SHC occurs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.7
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• pp.1058-1072
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• 1997

A head-neck complex dummy, for measuring brain pressure and reaction force in the cervical spine was developed for experimental study related in injury mechanism. Dummy comprised aluminium-casted head with water filled cavity for simulating brain and mechanical neck assembled with six motion segments. Several kinds of experiments (compression, bending, cyclic modulus, relaxation and constant velocity profile) for the developed mechanical neck showed that this neck model is biomechanically reliable compared with in-vitro test results. As an application of developed head-neck complex dummy, shock absorbing properties of protective helmet was chosen. The experiments showed that the maximum pressure increment of brain after impact was tolerable compared with the guide line for mild brain injury pressure (25psi). Constrast to this results, the reaction force in the neck was high enough to produce failure in the cervical spine.