• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.3
• /
• pp.39-46
• /
• 2016

Loss of postural stability can possibly lead to slip and fall accidents in the number of workplaces and everyday life. This study was aimed to examine the effects of whole body fatigue and partially limited visual field on the ability of maintaining postural balance during quiet standing. A group of twelve healthy male subjects participated in the experiment. Before and after experiencing the whole body fatigue induced by bicycling exercises, the position coordinates of subject's center of pressure (COP) were obtained under the two levels of visual field condition (i.e., open visual field and limited visual field). Four levels of the whole body fatigue examined were rest, 300watt, 600watt, and 900watt. Position coordinates of COPs measured on a force plate were then converted into the total length of postural sway path in both the medio-lateral (ML) direction and the anterior-posterior (AP) direction. Two-way ANOVA result showed that the length of sway path in the AP direction became significantly larger as the whole body fatigue accumulated. Post-hoc test revealed statistically significant differences between rest and 900watt and between 300watt and 900watt. The significant increase of the sway length was also found when the visual field was partially obstructed by the boxes. In the ML direction, however, there was no statistically significant difference of the postural sway in both the AP and ML directions. The results imply that the ability of maintaining postural stability can be reduced significantly due to such tasks along with whole body fatigue. The postural balance can also be impaired by the limited visual field.

• Journal of dental hygiene science
• /
• v.19 no.4
• /
• pp.279-287
• /
• 2019

Background: Increasing age and loss of teeth weaken oral muscle strength. This study aimed to investigate the positive effects of orofacial myofunctional training on elderly people. Methods: Thirty six elderly individuals in a welfare center and a senior citizen center were included in this study. A survey regarding lip and tongue strength suvsequent to orofacial myofunctional training and oral health-related quality of life was conducted from April to June, 2019. Data were analyzed using PASW statistics ver. 18.0. Results: The experimental group, showed an increase in lip strength (from 9.79 to 10.31) and tongue strength (from 41.26 to 43.97) after orofacial myofunctional training. The perception of oral health-relatedquality of life was enhanced (from 2.26 to 2.07). In particular, the frequency of dry cough for food removal while swallowing decresed due to an incresed in the secretion of saliva (p<0.05). Correlation analysis showed that the number of functional teeth was positively related to oral health-related quality of life. Conclusion: Orofacial myofunctional training for improving lip and tongue strength is effective in the elderly. In older societies, oral strength should be maintained to improve oral health-related quality of life. It also suggests the interest of oral health workers and applying orofacial myofunctional training programs.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.10
• /
• pp.1827-1836
• /
• 2017

The world dairy industry has long been challenged by bovine mastitis, an inflammatory disease, which causes economic loss due to decreased milk production and quality. Attempts have been made to prevent or treat this disease with multiple approaches, primarily through increased abuse of antibiotics, but effective natural solutions remain elusive. Bee venom (BV) contains a variety of peptides (e.g., melittin) and shows multiple bioactivities, including prevention of inflammation. Thus, in the current study, it was hypothesized that BV can reduce inflammation in bovine mammary epithelial cells (MAC-T). To examine the hypothesis, cells were treated with LPS ($1{\mu}g/ml$) to induce an inflammatory response and the anti-inflammatory effects of BV (2.5 and $5{\mu}g/ml$) were investigated. The cellular mechanisms of BV against LPS-induced inflammation were also investigated. Results showed that BV can attenuate expression of an inflammatory protein, COX2, and pro-inflammatory cytokines such as IL-6 and TNF-${\alpha}$. Activation of NF-${\kappa}B$, an inflammatory transcription factor, was significantly downregulated by BV in cells treated with LPS, through dephosphorylation of ERK1/2. Moreover, pretreatment of cells with BV attenuated LPS-induced production of intracellular reactive oxygen species (e.g., superoxide anion). These results support our hypothesis that BV can decrease LPS-induced inflammatory responses in bovine mammary epithelial cells through inhibition of oxidative stress, NF-${\kappa}B$, ERK1/2, and COX-2 signaling.

• The Korean Journal of Applied Statistics
• /
• v.29 no.7
• /
• pp.1311-1327
• /
• 2016

We propose a multi-state model for analyzing semi-competing risks data with interval-censored or missing intermediate events. This model is an extension of the 'illness-death model', which composes three states, such as 'healthy', 'diseased', and 'dead'. The state of 'diseased' can be considered as an intermediate event. Two more states are added into the illness-death model to describe missing events caused by a loss of follow-up before the end of the study. One of them is a state of 'LTF', representing a lost-to-follow-up, and the other is an unobservable state that represents the intermediate event experienced after LTF occurred. Given covariates, we employ the Cox proportional hazards model with a normal frailty and construct a full likelihood to estimate transition intensities between states in the multi-state model. Marginalization of the full likelihood is completed using the adaptive Gaussian quadrature, and the optimal solution of the regression parameters is achieved through the iterative Newton-Raphson algorithm. Simulation studies are carried out to investigate the finite-sample performance of the proposed estimation procedure in terms of the empirical coverage probability of the true regression parameter. Our proposed method is also illustrated with the dataset adapted from Helmer et al. (2001).

• Journal of Periodontal and Implant Science
• /
• v.48 no.4
• /
• pp.236-250
• /
• 2018

Purpose: Resorption of the alveolar bone is an unavoidable consequence of tooth extraction when appropriate alveolar ridge preservation (ARP) measures are not taken. The objective of this trial was to test the hypothesis that dimensional changes in the alveolar bone after tooth extraction would be reduced by inserting an equine collagen membrane and a collagen cone to fill and seal the alveolus (as ARP), in comparison to extraction with untreated alveoli. Methods: In this randomized clinical trial, 31 patients were directly treated with the collagen material after extraction of a tooth from the maxilla (the ARP group). Twenty-nine patients served as the control group. After extraction, no further treatment (i.e., no socket preservation measures) was performed in the control group. Changes in the alveolar process immediately after extraction and after an 8 (${\pm}1$)-week healing period were evaluated 3-dimensionally. Blinded analyses were performed after superimposing the data from the digitalized impressions and surfaces generated by cone-beam computed tomography. Results: Both the ARP and control groups showed a reduction of bone in the alveolar area after tooth extraction. However, significantly less bone resorption was detected in the clinically relevant buccal region in the ARP group. The median bone reduction was 1.18 mm in the ARP group and 5.06 mm in the control group (P=0.03). Conclusions: The proposed hypothesis that inserting a combination material comprising a collagen cone and membrane would lead to a difference in alveolar bone preservation can be accepted for the clinically relevant buccal distance. In this area, implantation of the collagen material led to significantly less alveolar bone resorption. German Clinical Trials Register at www.drks.de, DRKS00004769.

• Journal of Preventive Medicine and Public Health
• /
• v.32 no.3
• /
• pp.415-420
• /
• 1999

Objectives: We investigated the effects of changes in obesity and life style factors, such as cigarette smoking, alcohol drinking, and exercise, on the changes in blood pressure and serum cholesterol among Korean men. Methods: This study included 7,205 healthy male employees in the steel manufacturing industry. Each subject underwent health examination in 1994 and was re-examined in 1997. The study subjects were classified into four categories, according to changes in body mass index (BMI) (loss; stable; mild gain: severe gain), cigarette smoking (quitter; nor-smoker; smoker continued; smoker started), alcohol drinking (quitter; non-drinker; drinker continued; drinker started) and exercise (more exercise; continuous regular exercise; continuous irregular or no exercise; less exercise), respectively. We evaluated the relationship between the categories of change in those independent variables and the changes in blood pressure and serum cholesterol, adjusted for BMI in 1994 and age by analysis of variance. Results: The change in systolic blood pressure was positively associated with the changes in BMI (p<0.001) and drinking (p=0,001), but negatively with smoking (p=0,004), compared to the first category of each independent variables. The systolic blood pressure was significantly less increased in the continuous smoking group than quitter or hon-smoker. The changes in diastolic blood pressure and serum cholesterol appeared to have statistically significant linear relationships only with the change in BMI. The change in exercise showed a marginal significance with diastolic blood pressure (p=0.088). Conclusions: These prospective data emphasize the importance of obesity as a determinant of the changes in blood pressure and serum cholesterol. In addition, the changes in smoking and drinking habits can affect systolic blood pressure.

• Proceedings of the KIEE Conference
• /
• 2003.10b
• /
• pp.89-91
• /
• 2003

For the design to prevent the saturation of iron core and the effective fault current limitation, the analysis for the operation of the flux-lock type superconducting fault current limiter (SFCL) with consideration for the hysteresis characteristics of iron core is required. In this paper, the hysteresis characteristics of flux-lock reactor, which is an essential component of flux-lock type SFCL, was investigated. The hysteresis loss of iron core in flux-lock type SFCL does not happen due to its winding's structure especially in the normal state. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. Through the analysis for both the hysteresis curves and the fault current limiting characteristics due to the number of turns for the 1st and 2nd winding, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.5
• /
• pp.494-498
• /
• 2004

Fire accidents often happen in large buildings because large buildings are equipped with heavy electrical wiring and piping. When fire is to be occurred in those buildings, it is very dangerous to People and building structures. Therefore, multi-point wireless temperature sensors for large buildings are necessary in order to detect fire in the early time and thus to minimize the loss. A wireless device was composed of the transmitter and receiver. The specification of this device was as follows: 915MHz of transmitted frequency, 4 channels, 9600bps of the transmitted speed, and 10mW of the transmitted power. We confirmed through experiment that the temperature was well sensed and fire location was determined by the 4 channel sensors of the developed sensor system.

• Journal of Acupuncture Research
• /
• v.28 no.1
• /
• pp.15-28
• /
• 2011

Objectives : To understand the strength and weakness of traditional warm needle acupuncture based on existing research outcomes in Korea mostly and to suggest how to build the desirable warm needle acupuncture apparatus by overcoming demerits of traditional and currently existing ones. Methods : We searched warm needle relating papers in Korean with the key words of '온침, 화침, 열자극' by using DBpia, Journal of Korean Oriental Medical Society, Journal of Korean Acupuncture & Moxibustion Society and Journal of Society for Meridian and Acupoint. Degree dissertations in Korean were also searched with the same words through the search engine of Library of Kyung Hee University. We also searched with words of 'warm, thermal, heat, needle, acupuncture, temperature' via Pubmed and found a small number of English written papers and large number of Chinese written ones. To find english translated version of those papers, we googled with the same words with no success. Results : About 20 papers on warm needle acupuncture written in Korean were found and analyzed with respect to experimental factors that affected the thermal properties or the amount of heat stimulus of the acupuncture. More rigorous descriptions seemed to be required on the insertion depth, duration and manipulation of warm needle treatment. A basic heat transfer model was presented for the clarification of heat loss through the needle of warm needle acupuncture. Environmental factors such as air flow on the properties seems to be considered for the warm needle acupuncture. Conclusions : Papers on warm needle acupuncture were reviewed and analyzed based on their thermal properties and tools such as needles and moxa cones. Several suggestions were made on the descriptions relating the properties. Necessary specifications were introduced to aim modernized warm needle systems.

• The korean journal of orthodontics
• /
• v.41 no.3
• /
• pp.191-199
• /
• 2011

Objective: The purpose of this study was to investigate the stress distribution on the orthodontic mini-implant (OMI) surface and periodontal ligament of the maxillary first and second molars as well as the tooth displacement according to the OMI position in the dragon helix appliance during scissors-bite correction. Methods: OMIs were placed at two maxillary positions, between the first and the second premolars (group 1) and between the second premolar and the first molar (group 2). The stress distribution area (SDA) was analyzed by three-dimensional finite element analysis. Results: The maximal SDA of the OMI did not differ between the groups. It was located at the cervical area and palatal root apex of the maxillary first molar in groups 1 and 2, respectively, indicating less tipping in group 2. The minimal SDA was located at the root and furcation area of the maxillary second molar in groups 1 and 2, respectively, indicating greater palatal crown displacement in group 2. Conclusions: Placement of the OMI between the maxillary second premolar and the maxillary first molar to serve as an indirect anchor in the dragon helix appliance minimizes anchorage loss while maximizing the effect on scissors-bite correction.