• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.482-489
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• 2020

This study conducted a prototype development and evaluation by performing die-casting mold design, mold manufacturing, and injection condition optimization based on flow and solidification analysis to meet the needs of the coupling parts produced by die casting. Through flow analysis, the injection conditions suitable for 100% filling in the cavity were found to be a molten metal temperature of 670 ℃, injection speed of 1.164 m/s, and filling pressure of 6.324~18.77 MPa. In addition, solidification close to 100 % occurred in all four cavities when the solidification rate was 69.47 %. A defect inspection on the surface and inside the product revealed defects, such as poor molding and pores. In addition, the dimensions of the injected product were within the target tolerance and showed good results. Through the feedback of the results of flow and solidification analysis, it was possible to optimize the mold design, and the injection optimization conditions were confirmed to be a total cycle time of approximately 6.5 seconds. Good quality carrier parts with an average surface hardness of approximately 45 mm from the gate measured at 97.48(Hv) could be produced.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.430-435
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• 2000

Cleft lip and palate is one of the congenital anomalies which need comprehensive and multidisciplinary treatment plan because 1) oral cavity is an important organ with masticatory function as a start of digestive tract, 2) anatomic symmetry and balance is esthetically important in midfacial area, and 3) it is also important to prevent psycho-social problems by adequate restoration of normal facial appearance. There are many different protocols in the treatment of cleft lip and palate, but our department has adopted and modified the $Z{\"{u}}rich$ protocol, as published in the Journal of Korean Cleft Lip and Palate Association in 1998. The first challenge is feeding. Type of feeding aid ranges from simple obturators to active orthopedic appliances. In our department we use passive-type plate made up of soft and hard acrylic resin which permits normal maxillary growth. We use Millard's method to restore normal appearance and function of unilateral complete cleft lip. In consideration of both maxillary growth and phonetic problems, we first close soft palate at 18 months of age and delay the hard palate palatoplasty until 4 to 5 years of age. When soft palate is closed, posterior third of the hard palate is intentionally not denuded to allow normal maxillary growth. In hard palate palatoplasty the mucoperiosteum of affected site is not mobilized to permit residual growth of the maxilla. We have treated a patient with unilateral complete cleft lip and palate by Ajou protocol, which is a kind of modified $Z{\"{u}}rich$ protocol. It is as follows: Infantile orthopedics with passive-type plate such as Hotz plate, cheiloplasty with Millard's rotation-advancement flap, and two stage palatoplasty. It is followed by orthodontic treatment and secondary osteoplasty to augment cleft alveolus, orthognathic surgery, and finally rehabilitation with conventional prosthodontic treatment or implant installation. The result was good up to now, but we are later to investigate the final result with longitudinal follow-up study according to master plan by Ajou protocol.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.401-406
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• 2011

Purpose: The purpose of this study was to investigate changes in the position of the hyoid bone and soft palate and the amount of airway space after bilateral sagittal split ramus osteotomy (B-SSRO). Methods: This study is a review of lateral cephalometric tracings of 30 patients who underwent B-SSRO with setbacks at Kyunghee Dental Hospital from 2005 to 2009. Lateral cephalograms were taken before (T0), within one month (T1), and more than six months after the surgery (T2). Results: The hyoid bone at T1 changed significantly towards the inferoposterior position. At T2, it had significantly moved superiorly, but not anteriorly. At T1, the nasopharyngeal space, extending from the posterior nasal spine to the posterior pharyngeal space, decreased significantly, but did not show a significant increase at T2. The nasopharyngeal space, extending from the middle of soft palate to the posterior pharyngeal space, decreased significantly at T1, but did not show a significant decrease at T2. The oropharyngeal airway space decreased significantly at T1 and did not return to its original position at T2. The hypopharyngeal space, extending from the anterior to the posterior pharyngeal space at the level of the most anterior point of the third cervical vertebrae, slightly decreased at T1, but the amount was insignificant; however, the amount of decrease at T2 was significant. The hypopharyngeal space extending from the anterior to the posterior pharyngeal space at the level of the lowest point of the third cervical vertebrae, decreased significantly at T1 but returned to its original position at T2. Conclusion: B-SSRO changes the position of the hyoid bone and muscles inferoposteriorly. These change allows enough space for the tongue and prevent airway obstruction. Airway changes may be related to post-operative edema, posterior movement of the soft palate, anteroposterior movement of the hyoid bone, or compensation for decreased oral cavity volume. The position of the pogonion which measures anterior relapse after surgery did not show significant differences during the follow-up period.

• The korean journal of orthodontics
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• v.24 no.3 s.46
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• pp.659-672
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• 1994

Dental caries is one of the most prevalent dental diseases in Korea and its prevention is very important in orthodontic therapy. For the cleansing action of saliva itself and/or tooth-brushing is lowered in patient with fixed orthodontic appliance, oral hygiene of the patient becomes worse, which provides more favorable environment for micro-organisms. Chlorhexidine, one of the series of bisguanide, has been reported to be strong antimicrobial agent and very effective on Streptococcus mutans. The purpose of this study is to evaluate the possibility of chlorhexidine as a anticariogenic agent in fixed orthodontic therapy. We used the varnish containing chlorhexidine as a main ingredient for the chemical control of salivary S.mutans in patients with fixed appliance therapy We applied the varnish containing chlorhexidine on the labial and interproximal surface of the teeth before bonding and banding teeth of our patients(N=20) and compared to control group patients(N=20). Before the application of chlorhexidine varnish and four times periodically after the completion of fixed appliance set-up, we sampled saliva of both group patients and incuvate S.mutans for 24 hours. In the culture study of sampled saliva, counting the number of S.mutans colonies, we founded as follows : 1. In patients with fixed appliance therapy, the risk of dental caries increase when it compared to that of preorthodontic treatment ; The number of salivary S.mutans increase in Patient's oral cavity. 2. The experimental agent that contain chlorhexidine is effective to reduce the number of salivary S.mutans. 3. For the effect of this agent is not ever-lasting, periodical application is needed, and additional study for economical interval and number of application is needed.

• Journal of dental hygiene science
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• v.8 no.3
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• pp.207-214
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• 2008

The present study was based on the multicenter study and retrospective method of 200 patients with intraoral minor salivary gland tumors which were received at the Yonsei university dental hospital, Soonchunhyang Bucheon hospital and Yonsei university Severance hospital from 1990 to 2006. In this study, 61.5% of the cases were benign tumor and 38.5% were malignant tumor. Of the benign tumors, pleomorphic adenoma was the most common benign tumor (n=104) and Warthin's tumor, lymphangioma, myoepithelioma and basal cell adenoma were followed. Of the malignant tumors, adenoid cystic carcinoma was the most common malignant tumor (n=32) and mucoepidermoid carcinoma, adenocarcinoma, carcinoma ex pleomorphic adenoma, metastatic adenocarcinoma and acinic cell carcinoma were followed. The most common primary tumor location was palate. The result of this study was compared with other previous reviews and showed some differences.

• Journal of dental hygiene science
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• v.8 no.3
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• pp.117-122
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• 2008

The purpose of this study was to delve into how to provide better and more oral health education to middle school students, and to boost school oral health projects. The subjects in this study were 430 middle schoolers. After their oral health awareness, knowledge and oral health care were investigated, the following findings were given: 1. Concerning concern for oral health, 56.7 percent were oral health conscious, and as many as 43.2 percent were little or never concerned about it. 2. As to subjective oral health status, 36.7 percent found their own oral health status to be good, and 63.3 percent had a periodontal disease or felt that there was something wrong with their oral health. Regarding self-assessed abnormal oral symptoms, 25.8 percent considered themselves to have an abnormal symptom related to temporomandibular joint, and approximately 30 percent thought there was something wrong with their gums. 3. As for toothbrushing habits, the number of the girls who brushed their teeth after lunch was statistically significantly far larger than that of the boys who did. There were some differences between the boys and girls in toothbrushing method and in which part of the oral cavity they brushed. 4. In regard to oral health knowledge, the girls(a mean of 7.05) significantly excelled the boys(6.36). Those who were more oral health conscious got significantly better scores in oral health knowledge. 5. In terms of dental-clinic visit experiences, the students who had ever visited a dental clinic took in less sugar and got a more frequent regular dental checkup(2.62, 2.50) than the others who hadn't(2.32, 1.74).

• Journal of Korean society of Dental Hygiene
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• v.2 no.1
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• pp.21-41
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• 2002

This study is designed to offer basic materials necessary for the instruction of effective clinical practices and the establishment of relationship with patients by means of making an analysis of the characteristics of patients affecting the behavior of students majoring in dental hygiene avoiding patients and countermeasures. With this in mind, the researcher worked with sophomores and juniors exposed to clinical practices during the period ranging from October 22, 2001 to November 9, 2001. The researcher came to the following conclusions on the basis of the findings of this survey. 1. The characteristics of patients influencing the behavior of avoiding them were categorized into appearance characteristics, personality characteristics, treatment-cooperative characteristics, and speech and behavior characteristics. Speech and behavior characteristics(4.26) turned out to be the most influential factor of all, which was followed by treatment-cooperative characteristics(3.68), personality characteristics(3.62) and appearance characteristics(3.42) in the right order. 2. The survey shows that foul breath and obnoxious oral(3.94) cavity were the worst factors of appearance characteristics and that using abusive language and being too aggressive(4.41) were the worst factors of personality characteristics. The study reveals that not putting faith in trainees(4.02) was the highest factor of treatment-cooperative characteristics and that using abusive language(4.50) was the highest factor of speech and behavior characteristics. 3. There was a significant positive relation between the domains of the characteristics of avoiding patients. The study indicates that the more subjects avoided the characteristics of patients, the more they avoided appearance characteristics(r =.444, p<.001) and that the more subjects avoided treatment-cooperative characteristics, the more they avoided appearance characteristics(r=.324, P<.001) and personality characteristics(r=.691, p<.001), and that the more they avoided speech and behavior characteristics, the more they avoided appearance characteristics(r=.265, p<.001) and personality characteristics (r=.531, p<.001). 4. The study shows that there was a significant difference between appearance characteristics and the growth areas of the subjects(p<.05) and that there was a significant difference between the satisfaction of clinical practices(p<.05) and health status(p<.05) in terms of personality characteristics. 5. The subjects avoided preschoolers, whose age ranged from 4 to 6(33.5%), most and avoided boys(71.4%) more than girls. They avoided those who were bereft of jobs(62.9%). And they avoided handicapped persons most in terms of special patients and avoided infant patients(31.0%). 6. The subjects turned out to have negative and passive countermeasures against those patients that had ever been avoided. So the researcher would like to suggest that theoretic education and training programs should be conducted in this respect by incorporating this mailer into the hygiene curriculum.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.3
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• pp.257-265
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• 1999

To investigate the sequential changes in microvascular architecture and osseous regeneration during the bony healing after an application of the guided tissue regeneration method, we made artificial defects measuring $0.7cm{\times}0.3cm$ in size on femoral bones of rats measuring about 200gm and applied non-absorbable TEFE membrane at experimental sites but not at control sites. Then we observed the sequential changes and correlations between new vacuolation and bony regeneration using microvascular corrosion cast method and routine light microscopic observation at 1, 2 and 3 weeks after operation, respectively. The results showed that there were close relationships between regeneration of microvasculature and bone. In early phase, the invasion of granulation tissue at control sites delayed bony regeneration, however, in later phase, there was no remarkable differences in bony regeneration between control and experimental sites. The placement of barrier also affected in revascularization of regenerating bony defects. This is, the experimental sites showed parallel arranged nutritional vessels along long axis with well developed retiform plexus whereas the control revealed vertical invasion of microvasculature from outside of marrow space through bony defects which was also rearrange with time into parallel pattern with a vertical plexus but lesser organized than that of experimental sites. These findings suggest that the reconstruction of regenerating vasculature within the marrow cavity only may be sufficient and/or more be efficient in regeneration of bony defects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.306-313
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• 2017

Purple bamboo salt (PuBS) is commonly used as a medicinal food in Korea and has beneficial potentials such as antioxidant and anti-inflammatory effects. Rubus coreanus is called Bokbunja, which is used as a traditional medicine for treating asthma, impotence, and allergic diseases in Korea. The aim of present study was to investigate the immunostimulatory effect of PuBS composed with Rubus coreanus (PuBS-R). We performed comparative analysis between PuBS and PuBS-R in Raw264.7 cells, which is a mouse macrophage cell line, and peritoneal macrophages isolated primarily from the mouse peritoneal cavity. We evaluated cytotoxicity and the immune cytokine response in PuBS- and PuBS-R-treated cells. Both PuBS and PuBS-R did not have any cytotoxicity in Raw264.7 cells up to $500{\mu}g/mL$. Gene and protein levels of immune cytokines such as tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), $interferon-{\gamma}$ ($IFN-{\gamma}$), interleukin (IL)-10, and IL-12 were significantly elevated by PuBS-R more than PuBS in Raw264.7 cells. Moreover, we evaluated the immunostimulatory effects of PuBS-R on mouse primary peritoneal macrophages. Protein levels of inducible nitric oxide synthase, $TNF-{\alpha}$, $IFN-{\gamma}$, IL-10, and IL-12 were significantly higher in PuBS-R-treated peritoneal macrophages than PuBS-treated peritoneal macrophages. These results suggest the potential immunostimulatory effect of PuBS-R for immunity against harmful infection.

• Molecules and Cells
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• v.40 no.4
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• pp.299-306
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• 2017

The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.