• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.170-180
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• 1997

Cariogenicity of the bacteria is attributed to their binding capacity to the teeth. Bacterial attachment to oral surfaces is an essential step for colonization and subsequently infection. Therefore, it is conceivable that caries prevention can be achieved fundamentally by inhibition of bacterial attachment. The rationale for caries prevention through the use of sugar substitutes or limited use of sugar has been revealed. Among many sugar substitutes, xylitol has been shown to exhibit the most profound cariostatic effect, inhibiting glucose metabolism and possibly binding of mutans streptococci. The purpose of this study was to examine the effect of xylitol on binding of different species of oral bacteria. The effect of xylitol on binding of [$^3H$]-labeled oral bacteria to hydroxyapatite coated with human saliva(SHA) as a model for the pellicle-coated tooth surfaces was investigated. The strains of oral bacteria used in this study were A. viscosus T14V, A. viscosus WVU627, P. gingivaiis 2561, P. gingivalis A7Al-28, S. gordonii G9B, S. gordonii Challis, S. sobrinus 6715, S. mutans UA101, S. mutans KPSK -2, S. mutans T8, and S. mutans UA130. The obtained results were as follows: 1. P. gingivalis A7 Al-28, S. mutans UA130, S. mutans T8 grown with xylitol showed greater binding to SHA than the organism grown without xylitol. Among these, S. mutans T8 showed the greatest rate of increase in its binding to SHA ; 8-fold increase in its binding with xylitol. 2. S. mutans KPSK -2 grown with xylitol showed 2 times lesser binding to SHA than the organism grown without xylitol. 3. Binding ability of the remaining strains grown with xylitol to SHA was almost same as that of the organisms grown without xylitol. The overall results suggest that use of xylitol in the oral cavity may affect the complex oral bacterial ecosystem.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.464-469
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• 1997

The radiopacity of glass ionomer cements is quite variable. The use of a poorly radiopaque material as a base under other restorative materials can mislead the dentist to a diagnosis of recurrent decay. This study investigates the radiopacity of these materials and proposes a minimal radiopacity under which a material should not be used as a base or liner. It is important to determine the radiopacity of glass ionomer dental materials so that the clinician can appreciate the type of restorative materials used when radiographically evaluation the possibility of recurrent dental caries. In this study, radiopacity of Vitrement and Chemfil was compared with that of Cavalite, Miracle mix and polycarboxylate cement. Tooth model of artificial cavity preparation for diagnosis of recurrent caries was omitted. Radiopacity of each material was measured using relatives between thickness and radiopacity of Aluminium step wedge. The results were as follows : 1. Radiopacity of Vitrement was some higher than enamel. 2. Chemfil, restorative glass ionomer, was less radiopaque than enamel. 3. In order of higher radiopacity than enamel, Miracle mix was highest and was followed by polycarboxylate cement, Cavalite and Vitremer. 4. Vitremer, the Glass Ionomer Cement, is useful to detection of recurrent caries, because it is slightly higher radiopaque than enamel. So, it is suitable for restorative material and luting cement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.28-35
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• 2002

In cavity flow, the rectangular step generates so strong sound that many researchers have investigated method to suppress the nois during interaction between vortical flow and rectangular forward step. In this study the flow noise from the vortex motion in two-dimentional low Mach number flow past a forward step with various chamfering angle is calculated numerically. Inviscid incompressible discrete vortex model and matched asymptotic expansion(MAE) theory are applied to obtain the inner flow field and the outer noise field. Both source acoustic pressure and sound intensity are obtained with various chamfering height, chamfering angle and initial vortex position. The pressure amplitude is most suppressed when the chamfering angle is between $15^{\circ}C$ and $30^{\circC}$ at the chamfering length of 30% of the step height.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3199-3205
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• 2013

The inclusion behavior of sulfobutylether-${\beta}$-cyclodextrin (SBE-${\beta}$-CD) with perphenazine (PPH) was first studied by flow injection (FI)-chemiluminescence (CL) analysis with proposed $lg[(I_0-I_s)/I_s]=lgK_{P-CD}+nlg[C_{PPH}]$ model and molecular docking. Results showed that a 1:1 complex of SBE-${\beta}$-CD/PPH could online form, with the formation constant $K_{P-CD}$ of $2.57{\times}10^7Lmol^{-1}$ at 298 K. The thermodynamic parameters showed that the inclusion behavior of SBE-${\beta}$-CD/PPH was a spontaneous process by hydrophobic interaction. The molecular docking results revealed PPH entered into the larger cavity of SBE-${\beta}$-CD with two hydrogen bonds. Based on the linear relationship of the decrement of luminol/SBE-${\beta}$-CD/PPH CL intensity against the logarithm of PPH concentration ranging from 0.03 to 30.0 ng $mL^{-1}$, the present FI-CL analysis using luminol/SBE-${\beta}$-CD/PPH system was successfully applied to PPH determination in biological fluids and tablets with recoveries from 94.5 to 105.6% and RSDs less than 2.6% (n = 5).

• International Journal of Oral Biology
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• v.41 no.3
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• pp.125-131
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• 2016

The aim of the present study was to develop an animal model for evaluation of temporomandibular (TMJ) nociception under TMJ inflammation. We also investigated the participation of $IL-1{\beta}$ in inflammation-induced TMJ nociception. Experiments were carried out using male Sprague-Dawley rats. Intra-articular injection of 3% formalin was administered to evaluate hyperalgesia 3 days after CFA injection. Intra-articular injection of 3% formalin did not produce nociceptive behavior in normal rats. Although intra-articular injection of 3 doses of CFA produced TMJ inflammation, only 1:3 diluted CFA produced hyperalgesia when formalin was injected intra-articularly 3 days after CFA injection. Co-administration of IL-1 receptor inhibitor with formalin into the TMJ cavity 3 days after CFA injection was performed. Co-administration of IL-1 receptor inhibitor significantly inhibited formalin-induced hyperalgesia in rats with CFA-induced TMJ inflammation. These results suggested that intra-articular injection of formalin produced hyperalgesia under chronic TMJ inflammation. Moreover, $IL-1{\beta}$ plays an important role in TMJ hyperalgesia under chronic inflammation and blockade of $IL-1{\beta}$ is a potential therapeutic target for inflammatory TMJ pain.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.339-343
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• 2016

Background: Evaluation of deoxyribonucleic acid (DNA)-strand break is important to elucidate the biological effect of ionizing radiations. The conventional methods for DNA-strand break evaluation have been achieved by Agarose gel electrophoresis and others using an electrical property of DNAs. Such kinds of DNA-strand break evaluation systems can estimate DNA-strand break, according to a molecular weight of DNAs. However, the conventional method needs pretreatment of the sample and a relatively long period for analysis. They do not have enough sensitivity to detect the strand break products in the low-dose region. Materials and Methods: The sample is water, methanol and plasmid DNA solution. The plasmid DNA pUC118 was multiplied by using Escherichia coli JM109 competent cells. The resonance frequency and Q-value were measured by means of microwave dielectric absorption spectroscopy. When a sample is located at a center of the electric field, resonance curve of the frequency that existed as a standing wave is disturbed. As a result, the perturbation effect to perform a resonance with different frequency is adopted. Results and Discussion: The resonance frequency shifted to higher frequency with an increase in a concentration of methanol as the model of the biological material, and the Q-value decreased. The absorption peak in microwave power spectrum of the double-strand break plasmid DNA shifted from the non-damaged plasmid DNA. Moreover, the sharpness of absorption peak changed resulting in change in Q-value. We confirmed that a resonance frequency shifted to higher frequency with an increase in concentration of the plasmid DNA. Conclusion: We developed a new technique for an evaluation of DNA damage. In this paper, we report the evaluation method of DNA damage using microwave dielectric absorption spectroscopy.

• Wind and Structures
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• v.30 no.4
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• pp.325-338
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• 2020

In this paper, the improvement of the anti-snow performance of a high-speed train (HST) is studied using the unsteady Reynolds-Averaged Navier-Stokes simulations (URANS) coupled with the Discrete Phase Model (DPM). The influences of the proposed flow control scheme on the velocity distribution of the airflow and snow particles, snow concentration level and accumulated mass in the bogie cavities are analyzed. The results show that the front anti-snow structures can effectively deflect downward the airflow and snow particles at the entrance of the cavities and alleviate the strong impact on the bogie bottom, thereby decrease the local accumulated snow. The rotational rear plates with the deflecting angle of 45° are found to present well deflecting effect on the particles' trajectories and force more snow to flow out of the cavities, and thus significantly reduce the accretion distribution on the bogie top. Furthermore, running speeds of HST are shown to have a great effect on the snow-resistance capability of the flow control scheme. The proposed flow control scheme achieves more snow reduction for HST at higher train's running speed in the cold regions.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.42-53
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• 2002

This paper is for the hull form development of high-speed passenger ship in the Yellow Sea. To carry out hull form development in Yellow Sea, a catamaran which is designed for high-speed as well as comfortable passenger vessel up to now is selected and investigated. For this, environments of the Yellow Sea such as tide, water depth and so on are considered as important factor. The economical efficiency of the designed ship is considered too. In order to estimate the resistance characteristics of the designed hull form, numerical simulations and model test are performed.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.112-125
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• 2015

Making a model that is an accurate replica of the oral structure requires precision and efficiency. Nowadays, rapid technological advances bring digitalization in dentistry. One of the most important works in digital dentistry is three-dimensional modeling of the oral cavity and digitizing the 3D data. Among the three components of CAD/CAM, (1) data capture component (digitizers), (2) design component (CAD software), (3) manufacturing component (CAM), the basic component that has a significant impact on the other processes is the data capture component, i.e. intra-oral scanners. This literature review discusses the principles and clinical use of intra-oral scanners in dentistry based on recent publications of the past 5 years using the PubMed and Google Scholar databases.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.3
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• pp.69-80
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• 2014

Objective : Allergic rhinitis (AR) is an allergic inflammation of the nasal airways. Socheongryong-Tang traditionally has been used in Korea for treatment of allergy diseases. In the present study, we investigated whether SCRT suppresses the progression of AR in vivo and in vitro. Method : In this study, we investigated the effect of oral administration of SCRT on the Ovalbumin(OVA)-induced allergic rhinitis mouse models. Additionally, to find a possible explanation for the anti-inflammation effects of SCRT, we evaluated the inflammatory cytokine levels in LPS-stimulated mouse inflammation cell (RAW264.7) and mouse splenocyte. Results : The finding of this study demonstrated that SCRT reduced mast cells and inflammation cells infiltration in OVA-induced nasal cavity. Additionally, SCRT inhibited the production of inflammatory cytokines in splenocyte. However SCRT don't inhibited the production of inflammatory cytokines in RAW264.7 cells. Conclusion : Taken together, our results showed that oral administration of SCRT beneficial effects in allergic rhinitis, suggesting that SCRT might be a useful candidate for the treatment of allergic rhinitis.