• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.111-119
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• 2020

Objective: The purpose of this study is to apply exercise learning effect to various subjects through training effect and information accumulation based on verification of the effect on dumbbell curl exercises applied with virtual reality. Method: To analyze the effect on the dumbbell curl exercise in the virtual environment, a total of 20 persons with 10 males and 10 females who does not have orthopedics diseases were selected. The dumbbell weight of the subjects was set to a weight of 70% strength of 1RM. At this time, the virtual environment situation was set to four types; presence/absence of virtual environment, preferred colors, and unfavorable colors to perform dumbbell curl exercise. The anaysis of muscle activity was conducted by adhering four surface electrodes (Biceps Brachii, Triceps Brachii, Brachioradialis Muscle, Extensor Carpi Radialis Longus Muscle) on the right upper limbs. Independent sample t-test using SPSS (24.0) program was carried out to analyze average values and standard deviations for each variable depending on the presence/absence of virtual environments and changes in color (preferred colors, unfavorable colors) and the level of significance was set to a=.05. Results: In the eccentric contraction, males showed high muscle activity in the Biceps Brachii under virtual reality. On the other hand, females had high muscle activity in the Biceps Brachii in the absence of virtual reality. Also, in case of a change of colors in the virtual environment, females had the high muscle activity in the unfavorable color in the eccentric contraction. Conclusion: During the dumbbell curl exercise, results of different exercises present depending on gender. When males put VR on and performs a basic dumbbell curl exercise, the effect of Biceps presents Brachii for them while exercising in unfavorable colors. However, since it is the basic research data of muscle exercise using virtual reality, it is necessary to verify whether or not it is effective for myopachynsis through long-term training rather than unity.

• Safety and Health at Work
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• v.11 no.3
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• pp.291-300
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• 2020

Background: The study aimed to determine the association of individual cognitive ability in late midlife with labor market participation among older workers. Methods: This prospective cohort study estimates the risk of long-term sickness absence, disability pension, early retirement, and unemployment from scores on the Intelligenz-Struktur-Test 2000R by combining data from 5076 workers from the Copenhagen Aging and Midlife Biobank with a register on social transfer payments. Analyses were stepwise adjusted for age, gender, physical and psychosocial work environment, health behaviors, occupational social class, education, and chronic diseases. Results: In the fully adjusted model, low cognitive ability (≥1 standard deviation below the mean for each gender) and high cognitive ability (≥1 standard deviation above the mean for each gender) were not associated with risk of any of the four labor market outcomes. Conclusion: Individual cognitive ability in late midlife was not associated with risk of long-term sickness absence, disability pension, early retirement, and unemployment in the fully adjusted model. Thus, no direct effect of individual cognitive ability in late midlife was observed on the risk of permanently or temporarily leaving the labor market.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.23-30
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• 2007

The effects of high energy short wave solar radiation on human skin have received much publicity as the major cause of accelerated skin ageing and of skin cancers. To meet public demand, the cosmetic industry has developed sun protection factor products, which contain a variety of so-called "UV filters", among others benzophenone (BP) and its metabolites are the widely used UV filters. UV filters are also used to prevent UV light from damaging scents and colors in a variety of cosmetics products and to protect of plastic products against light-induced degradation. There are many variants of BP in use. In this respect, to regulate and to evaluate the hazardous effect of BP-type UV filters will be important to environment and human health. The genotoxicity of 7 BP-type UV filters was evaluated in L5178Y $(tk^{+/-})$ mouse lymphoma cells in vitro. BP, benzhydrol, 4-hydroxybenzophenone 2-hydroxy-4-methoxybenzophenone and 2, 4-dihydroxybenzophenone did not induce significant mutation frequencies both in the presence and absence of metabolic activation system. 2, 2'-Dihydroxy-4-methoxybenzophenone appeared the positive results at the highest dose, i.e. 120.4 ${\mu}g/mL$ only in the absence of metabolic activation system. And also, 2, 3, 4-trihydroxybenzophenone revealed a significant increase of mutation frequencies in the range of 138.1-207.2 ${\mu}g/mL$ in the absence of metabolic activation system and 118.3-354.8 ${\mu}g/mL$ in the presence of metabolic activation system. Through the results of MLA with 7 BP-type UV filters in L5178Y cells in vitro, we may provide the important clues on the genotoxic potentials of these BP-type UV filters.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.53-59
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• 2007

This study was conducted to evaluate the mutagenic potential of dimethyl isophthalate (DMIP) using Ames bacterial reverse mutation test, chromosomal aberration test and mouse lymphoma $tk^{+/-}$ gene assay. As results, in Ames bacterial reversion assay, DMIP was tested up to the concentration of 5,000 ${\mu}g$/plate and did not induce mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli WP2uvrA with or without metabolic activation (S9 mix). Using cytotoxicity test, the maximal doses of DMIP for chromosomal aberration assay were determined at 1,250 ${\mu}g/mL$, which was a minimum precipitation concentration ($IC_{50}>1,940\;{\mu}g/mL$ or 10 mM) and at 155 ${\mu}g/mL$ ($IC_{50}:155\;{\mu}g/mL$) in the presence and the absence, respectively, of S9 mix. DMIP in the presence of S9 mix induced statistically significant (P<0.001) increases in the number of cells with chromosome aberrations at the dose levels of over 250 ${\mu}g/mL$, when compared with the negative control. However, DMIP in the absence of S9 mix did not caused significant induction in chromosomal aberrant cells. In MLA, DMIP at the dose range of 242.5-1,940 ${\mu}g/mL$ in the presence of S9 mix induced statistically significant increases in mutation frequencies related to small colony growth, whereas any significant mutation frequency was not observed in absence of S9 mix. From these results, it is conclusively suggested that dimethyl isophthalate may be a clastogen rather than a point mutagen.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.175-182
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• 2010

In this paper, we propose a robust speech reinforcement technique to enhance the intelligibility of the degraded speech signal under the ambient noise environments based on soft decision scheme incorporating a speech absence probability (SAP) with speech reinforcement gains. Since the ambient noise significantly decreases the intelligibility of the speech signal, the speech reinforcement approach to amplify the estimated clean speech signal from the background noise environments for improving the intelligibility and clarity of the corrupted speech signal was proposed. In order to estimate the robust reinforcement gain rather than the conventional speech reinforcement method between speech active periods and nonspeech periods or transient intervals, we propose the speech reinforcement algorithm based on soft decision applying the SAP to the estimation of speech reinforcement gains. The performances of the proposed algorithm are evaluated by the Comparison Category Rating (CCR) of the measurement for subjective determination of transmission quality in ITU-T P.800 under various ambient noise environments and show better performances compared with the conventional method.

• Toxicological Research
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• v.20 no.1
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• pp.43-47
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• 2004

In order to investigate the safety of a water extract (ADP) of 1 : 1 mixture of Anemarrhena rhizoma and Phellodendron cortex for alleviating benign prostate hyperplasia, genotoxicity studies in bacterial and mammalian cell assay systems, namely, the Ames bacterial reverse mutation and chromosomal aberration assays were performed. As shown by the results of the Ames bacterial reversion assay, ADP in the range of 625-5000 $\mu\textrm{g}$/plate did not induce mutagenicity in Salmonella typhimurium TA 98, TA 100, TA 1535 and TA 1537 strains in the absence or in the presence of S9 (the microsomal fraction of rat liver homogenate) metabolic activation. The $IC_{50}$ (50% cell growth inhibition concentration) values of ADP for the chromosomal aberration assay were determined; these were 2425 $\mu\textrm{g}$/ml in the absence and 8126 $\mu\textrm{g}$/ml in the presence of S9 metabolic activation in Chinese hamster lung (CHL) fibroblast cell culture. No chromosomal aberration was observed in CHL cells treated with ADP at 2425, 1212.5 and 606.25 $\mu\textrm{g}$/ml in the absence, or at 8126, 4063 and 2031.5 $\mu\textrm{g}$/ml in the presence of S9 metabolic activation. These results show that under the conditions used, ADP does not harmfully affect the bacterial or mammalian cell system at the gene level.

• Journal of Periodontal and Implant Science
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• v.47 no.3
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• pp.182-192
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• 2017

Purpose: Contact and distance osteogenesis occur around all endosseous dental implants. However, the mechanisms underlying these processes have not been fully elucidated. We hypothesized that these processes occur independently of each other. To test this, we used titanium (Ti) tubes to physically separate contact and distance osteogenesis, thus allowing contact osteogenesis to be measured in the absence of possible triggers from distance osteogenesis. Methods: Sandblasted and acid-etched (SLA) and modified SLA (modSLA) implants were used. Both types had been sandblasted with large grit and then etched with acid. The modSLA implants then underwent additional treatment to increase hydrophilicity. The implants were implanted into rabbit tibiae, and half were implanted within Ti tubes. The bone-to-implant contact (BIC) ratio was calculated for each implant. Immunohistochemical analyses of bone morphogenetic protein (BMP)-2 expression and new bone formation (Masson trichrome stain) were performed. Results: The implants outside of Ti tubes were associated with good bone formation along the implant surface. Implantation within a Ti tube significantly reduced the BIC ratio (P<0.001). Compared with the modSLA implants, the SLA implants were associated with significantly higher BIC ratios, regardless of the presence or absence of Ti tubes (P=0.043). In the absence of Ti tubes, the bone adjacent to the implant had areas of new bone formation that expressed BMP-2 at high levels. Conclusions: This study disproved the null hypothesis and suggested that contact osteogenesis is initiated by signals from the old bone that undergoes distance osteogenesis after drilling. This signal may be BMP-2.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.1-7
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• 2013

A pure oxygen combustion technology is crucial in Carbon Capture and Storage (CCS) technology especially in capturing of $CO_2$, where CCS will reduce 9 $GtCO_2$ by 2050, which is 19% of the total $CO_2$ reduction amount. To make pure oxygen combustion feasible, a regenerative system is required to enhance the efficiency of pure oxygen combustion system. However, an existing air combustion technology is not directly applicable due to the absence of nitrogen that occupies the 78% of air. This study, therefore, investigates the heat and fluid flow in a regenerative system for pure oxygen combustion by using commercial CFD software, FLUENT. Our regenerative system is composed of aluminium packed spheres. The effect of the amount of packed spheres in regenerator and the effect of presence or absence of a bypass of exhaust gas are investigated. The more thermal mass in regenerator makes the steady-state time longer and temperature variation between heating and regenerating cycle smaller. In the case of absence of bypass, the regenerator saturates because of enthalpy imbalance between exhaust gas and oxygen. We find that 40% of exhaust gas is to be bypassed to prevent the saturation of regenerator.

• Korean Institute of Interior Design Journal
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• v.22 no.1
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• pp.164-173
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• 2013

This study aims to analyze the aesthetic thought and expression tendency appeared in contemporary architecture by looking at today's architectural art based on the concept of the uncanny that Sigmund Freud contended as an aesthetic principle, of the aesthetic concepts tossed around to define the contemporary times in the aesthetics field and discuss the architectural analysis possibility of the concept of the uncanny. The generation structure of the uncanny that generates experiences of fear and surprise is classified into dual structure, trauma, threatening structure, and repetition compulsion. This is the principle that evokes a sense of experiencing subject, incorporates sensibility, and vitalizes internal process. This is also the methodology to organize and structure the concept of the uncanny. When seen from the four factors drawn from the concept of the uncanny and aesthetic expressions, the uncanny expression characteristics of contemporary architecture includes isolation, subversion, trace, absence, oblique line, flotation, concealment, and disturbance. Isolation and subversion refers to producing the space of the pressure of tension and relaxation caused by repression and relief from repression and eliciting the maximum expansion of the sense of space through spatial change. Trace and absence indicates being able to elicit more intense emotions from the experiencing subject by applying the images of alienation and absence in the way to reproduce historical trauma. This happens by implementing the potential value of physical activity. Oblique line and flotation means visual impulse. This happens in the way to visualize uneasy points. This causes uncanny by threatening the survival. Finally, concealment and disturbance refers to creating unpredictable space. The concept of masquerade and maze space composition are applied in the way to activate spatial perception, including space exploration and unintended subject's forced selection. As stated above, the uncanny expression characteristics shown in contemporary architecture can be presented as indicators that are available to analyze the undecided and diversified contemporary architecture aesthetically. In this respect, this study has great significance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.539-546
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• 2016

In this paper, the effect of J-R curve changes on the determination of parameters in a failure model owing to the presence or absence of a side groove in a C(T) specimen is investigated. A stress-modified fracture strain model is implemented for FE damage simulations. C(T) specimens were taken from SA508 grade 1a low-alloy steel piping material, and some of them were processed with a side groove. Fracture toughness tests were performed at room temperature and at $316^{\circ}C$. The parameters of the failure model were determined by damage simulations using the J-R curves obtained from the tests. Finally, the results show that the determination of failure model parameters is not affected by variations in J-R curves owing to the presence or absence of a side groove.