• Korean Journal of Health Education and Promotion
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• v.26 no.2
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• pp.63-73
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• 2009

Objectives: The purpose of this study was to identify the degree of internet addiction and factors affecting internet addiction in elementary school students. Methods: A cross-sectional survey design was employed in this study. The subjects were 378 students who were recruited from 5th and 6th grade in five elementary schools in J city, Korea. Data were collected through a structured questionnaire. The data were analyzed using the SPSS Win 10.1 program. Results: Of the children, 51.9% reported being average online users, 45.5%, heavy online users, and 2.6%, internet addicted. The level of internet addiction of subjects correlated significantly with the behavioral activation system, behavioral inhibition system, family cohesion, and learned self-concept, but not family adaptability. Significant predictors influencing internet addiction were the behavioral activation system, learned self-concept, and family cohesion. These predictors accounted for 22% of variance in internet addiction. Conclusion: This study found that the behavioral activation system in personality aspects, family cohesion in the family system, and learned self-concept are primary factors that explain internet addiction among elementary students. We suggest these results be used to develop an online addiction prevention or treatment program.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.330-335
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• 2014

Objectives: To evaluate the mutagenicity of lithium carbonate, a bacterial reverse mutation(Ames) test was carried out using four strains of S. typhimurium(TA1535; TA1537; TA98; and TA100) and one strain of E. coli(WP2uvrA). Materials: This was carried out in a dose range from 312.5 to $5,000{\mu}g/plate$ in triplicate with and without S9 activation, which is the most commonly used metabolic activation system supplemented by a post-mitochondrial fraction prepared from the livers of rodents treated with enzyme-inducing agents such as Aroclor 1254 or a combination of phenobarbitone and ${\beta}$-naphthoflavone. Results: No significant increases in the number of revertants were observed under the conditions examined in this study. Conclusions: Based on the above observations, it can be concluded that lithium carbonate has no mutagenic activity. Despite the results, it can have an effect by inducing acute oral toxicity, eye irritation and acute aquatic toxicity. Based on this study, we suggest that future studies should be directed toward chronic, carcinogenic testing and other related areas.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.27-34
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• 2014

In this study, we evaluated an effect of the tempered materials on the thermal runaway characteristics in the resol resin synthesis reaction using the adiabatic calorimetry of vent sizing package 2(VSP2). The kinetic parameters, such as an activation energy and heat of reaction, were estimated using the test results. As the results, the instantaneous characteristics to express the intensity of runaway reaction decreased at the low solid content. However, the sudden loss of the tempered materials triggered the second runaway reaction rapidly. In this condition, the heat of reaction and the activation energy of phenol and p-formaldehyde were about 157 kJ/mol and 60 kJ/mol, respectively.

• BMB Reports
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• v.55 no.10
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• pp.473-480
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• 2022

Neutrophils, the most abundant innate immune cells, play essential roles in the innate immune system. As key innate immune cells, neutrophils detect intrusion of pathogens and initiate immune cascades with their functions; swarming (arresting), cytokine production, degranulation, phagocytosis, and projection of neutrophil extracellular trap. Because of their short lifespan and consumption during immune response, neutrophils need to be generated consistently, and generation of newborn neutrophils (granulopoiesis) should fulfill the environmental/systemic demands for training in cases of infection. Accumulating evidence suggests that neutrophils also play important roles in the regulation of adaptive immunity. Neutrophil-mediated immune responses end with apoptosis of the cells, and proper phagocytosis of the apoptotic body (efferocytosis) is crucial for initial and post resolution by producing tolerogenic innate/adaptive immune cells. However, inflammatory cues can impair these cascades, resulting in systemic immune activation; necrotic/pyroptotic neutrophil bodies can aggravate the excessive inflammation, increasing inflammatory macrophage and dendritic cell activation and subsequent T_H1/T_H17 responses contributing to the regulation of the pathogenesis of autoimmune disease. In this review, we briefly introduce recent studies of neutrophil function as players of immune response.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.40-46
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• 2016

Objective: The purpose of this study was to examine the effect on multifidus and external oblique abdominis muscle activation during hip contraction of three types (concentric, isometric, eccentric) in standing position. Design: Cross-sectional study. Methods: Twenty healthy adult men volunteered to participate in this study. Muscle activation was recorded from gluteus maximus, both multifidus, and both external oblique abdominis by surface electromyography (EMG) while holding position in the type of gluteus maximus contraction. EMG values were normalized by maximum muscle contractions (% maximum voluntary isometric contraction). All subjects performed hip extension with three contraction methods. The type of gluteus maximus contraction using Thera-band was composed of concentric contraction (type 1), isometric contraction (type 2), and eccentric contraction (type 3). To measure muscle activation on the gluteus maximus contraction type, each position were maintained for 5 seconds with data collection taken place during middle three seconds. Muscle activation was measured in each position three times. Results: For the results of this study, there was no significant difference within three contraction patterns of the gluteus maximus (concentric, isometric, and eccentric) each both multifidus, both external oblique abdominis, and gluteus maximus. And there was no significant difference among both multifidus, both external oblique abdominis, and gluteus maximus each hip extension contraction type. Conclusions: These findings suggest that specific contraction types of the gluteus maximus does not lead to a more effective activation of the multifidus, external oblique abdominis, and gluteus maximus.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.1
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• pp.17-22
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• 2016

The activation energy of a material is an important factor that significantly affects the lifetime and can be used to develop a degradation model. In this study, a thermal analysis was carried out to evaluate and collect quantitative data on the degradation of insulation materials like EPR and CSP used for nuclear power plant cables. The activation energy was determined from the relationship between log ${\beta}$ and 1/T based on the Flynn.Wall.Ozawa method, by a TGA test. The activation energy was also derived from the relationship between ln(t) and 1/T based on isothermal analysis, by an OIT test. The activation energy of EPR derived from thermal analysis was used to calculate the accelerated aging time corresponding to the number of years of use, employing the Arrhenius equation, and determine the elongation corresponding to the accelerated aging time.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1294-1298
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• 2008

Toll-like receptors (TLRs) induce innate immune responses recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor-${\kappa}B$ (NF-${\kappa}B$). The activation of NF-${\kappa}B$ leads to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Guggul has been used for centuries to treat a variety of diseases. Guggulstreone, one of the active ingredients in guggul, has been used to treat many chronic diseases. However, the mechanism as to how guggulsterone mediate the health effects is largely unknown. Here, we report biochemical evidence that guggulsterone inhibits the NF-${\kappa}B$ activation and COX-2 expression induced by TLR2, TLR3, and TLR4 agonists. Guggulsterone also inhibits the NF-${\kappa}B$ activation induced by downstream signaling components of TLRs, myeloid differential factor 88 (MyD88), $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$), and p65. These results imply that guggulsterone can modulate the immune responses regulated by TLR signaling pathways.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.45-53
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• 2019

This study is a neutron activation for concrete that shields medical linear accelerator facilities. Comparison of general concrete and low activation concrete. The simulation method was simulated using MCNPX (Ver. 2.5.0) and FISPACT-2010, and the shielding ability for photon and neutron beams was calculated and neutron activation evaluation was carried out. As a result, the shielding capacity was 20 ~ 50 cm efficient in general concrete, and activate evaluation in low activation concrete was calculated to be low in radioactivity concrete, but all were estimated to not exceed their own allowable concentration in self - disposal. As a result of the comprehensive analysis, it is considered effective to use ordinary concrete.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1175-1182
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• 2021

We investigated the effect of bovine lactoferricin (Lfcin-B), a peptide derived from bovine lactoferrin, on activation of intestinal epithelial cells in IEC-6 intestinal cell, and protection against in vivo rotavirus (RV) infection. Treatment with Lfcin-B significantly enhanced the growth of IEC-6 cells and increased their capacity for attachment and spreading in culture plates. Also, Lfcin-B synergistically augmented the binding of IEC-6 cells to laminin, a component of the extracellular matrix (ECM). In the analysis of the intracellular mechanism related to Lfcin-B-induced activation of IEC-6 cells, this peptide upregulated tyrosine-dependent phosphorylation of focal adhesion kinase (FAK) and paxillin, which are intracellular proteins associated with cell adhesion, spreading, and signal transduction during cell activation. An experiment using synthetic peptides with various sequences of amino acids revealed that a sequence of 9 amino acids (FKCRRWQWR) corresponding to 17-25 of the N-terminus of Lfcin-B is responsible for the epithelial cell activation. In an in vivo experiment, treatment with Lfcin-B one day before RV infection effectively prevented RV-induced diarrhea and significantly reduced RV titers in the bowels of infected mice. These results suggest that Lfcin-B plays meaningful roles in the maintenance and repair of intestinal mucosal tissues, as well as in protecting against intestinal infection by RV. Collectively, Lfcin-B is a promising candidate with potential applications in drugs or functional foods beneficial for intestinal health and mucosal immunity.

• Journal of Korean Physical Therapy Science
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• v.29 no.3
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• pp.21-28
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• 2022

Background: Hamstring shortness results in the inappropriate activation of the quadriceps femoris because of the loss of the reciprocal inhibition mechanism. The purpose of this study was to investigate the effects of that activation during lunge exercises on the vastus medialis, vastus lateralis, medial, and lateral hamstrings in participants with hamstring shortness and normal length. Design: Quasi-experimental design Methods: Participants were divided into a hamstring shortness group(n=20) and a hamstring normal length group(n=23), based on a hamstring length test. During lunge exercises, muscle activation of the vastus lateralis, vastus medialis, medial, and lateral hamstrings were measured by electromyography. Results: Each muscle tested was less activated in the hamstring shortness group than in the hamstring normal length group. However, there was no statistically significant difference between the groups (p>.05). Conclusion: Although there was no significant difference between the shortness and normal hamstring groups during short lunge exercise time, longer exercising periods will result in the inappropriate activation of the quadriceps femoris. During lunge exercise, hamstring shortness causes an imbalance activation of quadriceps femoris and hamstring, and continuous hamstring shortness can cause damage on joints of lower limb.