• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1417-1424
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• 2015

In this study, we tried to characterize Streptomyces peucetius CYP157C4 with homology modeling using three cytochrome P450 (CYP) structures (CYP157C1, CYP164A2, and CYP107L1), having discovered that CYP157C4 lacks the ExxR motif that was considered invariant in all CYPs. We used Discovery Studio 3.5 to build our model after first assessing the stereochemical quality and side-chain environment, and a 7-ethoxycoumarin substrate was docked into the final model. The model-substrate complex allowed us to identify functionally important residues and validate the active-site architecture. We found a distance of 4.56 Å between the 7-ethoxycoumarin and the active site of the heme, and cloning and an in vitro assay of the CYP157C4 showed the dealkylation of the substrate. Since the details regarding this group of CYP structures are still unknown, the findings of this study may provide elucidation to assist with future efforts to find a legitimate substrate.

• Journal of the Korean Society of Safety
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• v.21 no.6 s.78
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• pp.106-115
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• 2006

The purpose of this study is to provide basic data for continuing study in order to accomplish preventive countermeasures for work-related musculoskeletal disorders(WMSD) and to examine related factors in connection with each other as: the working environment, the equipment used, working method, pain symptoms of dentists. The investigation period for this study was from November 1, 2004 to February 28, 2005, and we analyzed questionnaire survey of 190 dentists who were giving medical treatment in and around the metropolitan area and Daegu City. Also, we visited 20 dental hospitals personally and examined the work posture through check lists, interviews, and field investigations on work posture using photos and videotaping. This study showed the increasing physical burdens which were related to dentists work accomplishment and attitude, recognizing pain which were affecting work related WMSD. With the access of ergonomics and improving the education and training of awkward medical treatment methods and posture, and continuous public information about WMSD, the occurrence rate of WMSD could be decreased.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.53-62
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• 2016

Mesenchymal stem cells (MSCs) in the bone marrow and other somatic tissues reside in an environment with relative low oxygen tension. Cobalt chloride ($CoCl_2$) can mimic hypoxic conditions through transcriptional changes of some genes including hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$) and vascular endothelial growth factor (VEGF). This study evaluated the potential role of $CoCl_2$ preconditioning on multi-lineage differentiation of C3H/10T1/2, a murine MSC line to understand its possible molecular mechanisms in vitro. $CoCl_2$ treatment of MSCs markedly increased HIF-$1{\alpha}$ and VEGF mRNA, and protein expression of HIF-$1{\alpha}$. Temporary preconditioning of MSCs with $CoCl_2$ induced up-regulation of osteogenic markers including alkaline phosphatase, osteocalcin, and type I collagen during osteogenic differentiation, followed by enhanced mineralization. $CoCl_2$ also increased chondrogenic markers including aggrecan, sox9, and type II collagen, and promoted chondrocyte differentiation. $CoCl_2$ suppressed the expression of adipogenic markers including $PPAR{\gamma}$, aP2, and $C/EBP{\alpha}$, and inhibited adipogenesis. Temporary preconditioning with $CoCl_2$ could affect the multi-lineage differentiation of MSCs.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.2
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• pp.103-108
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• 2014

Head restraining is an experimental technique that firmly secures the animal's head to a fixation apparatus for the precise control and sensing of behaviors. However, procedural and surgical difficulties and limitations have been obstructing the use of the technique in neurophysiological and behavioral experiments. Here, we propose a novel design of the head-restraining apparatus which is easy to develop and convenient for practical use. Head restraining procedure can be completed by sliding the head mounter, which is molded by dental cement during implantation surgery, into the port, which serves as matching guide rails for the mounter, of the fixation bar. So neither skull-attached plates nor screws for fixation are needed. We performed intracranial self stimulation experiment in rats using the newly designed device. Rats were habituated to acclimatize the head-restraint environment and trained to discriminate two spatially distinguished cues using a customized push-pull lever as an operandum. Direct electrical stimulation into the medial forebrain bundle served as reward. We confirmed that head restraining was stable throughout experiments and rats were able to learn to manipulate the lever after successful habituation. Our experimental framework might help precise control or sensing of behavior under head fixed rats using direct electrical brain stimulation as a reward.

• Textile Coloration and Finishing
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• v.18 no.6 s.91
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• pp.43-48
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• 2006

Electrolytic water(EW), studied in recent decades in the Japan, Russia and United State of America, have shown promise as a method of disinfection whereby low levels of free chlorine, sodium hypochlorite, or hypochlorous acid may be produced in situ in Nacl-containing solution. These methods have shown promise in destruction of microorganisms in medical, dental environment, and in the agriculture and food industry. A recently EW treatment system was evaluated for reducing scouring agent and other surfactants in the washing and scouring process of textile industry Unfortunately, there is, to my knowledge, no serious studies of the properties of EW for textile industry In order to study the characteristics of EW and confirm the possibility of applications in textile industry processes, the pH, surface activity, penetration force, surface tension, and contact angle of EW was measured under various conditions. In general terms, What all this shows is that there is fundamental difference between the properties of EW and that of distilled water.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.2
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• pp.312-322
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• 1998

There are many concerns about the erosive effect of acidic beverage. In this study, the erosive effect of bovine enamel caused by $Pepsi-Cola^{(R)}$(pH 2.41) and rehardening effect by intraoral exposure were determined by microhardness test and SEM. The bovine enamel specimen was imbedded in 100ml $Pepsi-Cola^{(R)}$ during 5 minutes and exposed to the intraoral environment with removable resin plate. The microhardness test was performed after 1 hr, 24 hrs, and 48 hrs. The results obtained from this study can be summarized as follows ; 1. The microhardness value was significantly (p<0.05) reduced by cola beverage, and significantly (p<0.05) increased after 1 hr and 24 hrs respectively. 2. The difference in the microhardness between 24 hrs group and 48 hrs group was not significant (p>0.05) and microhardness value of 48 hrs group was significantly less than that of initial group (p<0.05). 3. The erosive effect of cola beverage and remineralization effect by intraoral exposure were visualized by the SEM photo. But, the enamel surfaces did not return to their original state.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.1
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• pp.38-42
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• 2016

The purpose of this study is to evaluate the degree of osseointegration of resorbable blasting media (RBM) surface implants retrieved from humans. Three implants in the mandibular molar region that were surface-treated with RBM were retrieved from two patients. The implants were used to manufacture specimens in order to measure the bone-implant contact (BIC) ratio. The BIC ratios of the three implants were found to be an average of $69.0%{\pm}9.1%$. In conclusion, that RBM surface implants are integrated into the host environment with histological significance and the BIC ratio of the RBM surface-treated implant was not significantly different from that of other surface-treated implants.

• Journal of Oral Medicine and Pain
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• v.40 no.1
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• pp.17-27
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• 2015

Purpose: The purpose of this study was to investigate occupational distribution of temporomandibular disorders (TMD) patients and their diagnosis according to occupations and to evaluate the relationship between TMD and occupations. Work-related factors which might aggravate TMD symptoms were also evaluated. Methods: We investigated 316 TMD patients, aged from 13 to 65 years old, who had visited the Department of Oral Medicine in Pusan National University Dental Hospital. The subjects who have a job were assessed using TMD analysis examination and occupation questionnaire. The level of significance was p-value<0.05. Result: This study presented that the diagnoses according to occupations were not significant, but work-related factors such as verbal work and poor posture were related with TMD symptoms. Conclusions: Proper education is essential to prevent aggravation of TMD symptoms because TMD symptoms were more related to work environment than a specific occupation.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.1
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• pp.31-38
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• 2021

Purpose: The purpose of this study was to investigate effect of heme on periodontopathogens. Materials and Methods: The experiment was performed using 7 types of anaerobic bacteria present in the periodontal pocket. The bacteria were cultured using suitable medium in an anaerobic condition with or without hemin, and the growth of the bacteria was measured every 6 hours by a spectrophotometer. Results: the growth of Porphyromonas gingivalis was different only by the presence or absence of hemin. The growth of other periodontopathogens except Treponema denticola was different in a hemin concentration-dependent manner. The growth of T. denticola was interfered by hemin. Conclusion: Heme may be a factor that leads dysbiosis in the microbial ecosystem of the subgingival plaque and thereby promote a periodontitis-causing environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1213-1220
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• 2022

This study was conducted to understand how to derive educational methods to efficiently improve class satisfaction for 130 college students who experienced non-face-to-face classes during the last Covid-19. The appropriateness of class time, improvement of learning effect, continuity of non-face-to-face classes, and use of educational media were set as items corresponding to class satisfaction. Research was attempted to derive an educational method for efficient class satisfaction improvement by grasping the difference and relationship between variables.