• The Journal of Information Systems
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• v.30 no.2
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• pp.29-56
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• 2021

Purpose Cyber deviance of adolescents has become a serious social problem. With a widespread use of smartphones, incidents of cyber deviance have increased in Korea and both quantitative and qualitative damages such as suicide and depression are increasing. Research has been conducted to understand diverse factors that explain adolescents' delinquency in cyber space. However, most previous studies have focused on a single theory or perspective. Therefore, this study aims to comprehensively analyze motivations of juvenile cyber deviance and to develop a predictive model for delinquent adolescents by integrating four different theories on cyber deviance. Design/methodology/approach By using data from Korean Children & Youth Panel Survey 2010, this study extracts 27 potential factors for cyber deivance based on four background theories including general strain, social learning, social bonding, and routine activity theories. Then this study employs econometric analysis to empirically assess the impact of potential factors and utilizes a machine learning approach to predict the likelihood of cyber deviance by adolescents. Findings This study found that general strain factors as well as social learning factors have positive effects on cyber deviance. Routine activity-related factors such as real-life delinquent behaviors and online activities also positively influence the likelihood of cyber diviance. On the other hand, social bonding factors such as community commitment and attachment to community lessen the likelihood of cyber deviance while social factors related to school activities are found to have positive impacts on cyber deviance. This study also found a predictive model using a deep learning algorithm indicates the highest prediction performance. This study contributes to the prevention of cyber deviance of teenagers in practice by understanding motivations for adolescents' delinquency and predicting potential cyber deviants.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.4
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• pp.337-344
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• 2021

Background: The primary indication for using long-acting anesthetics in dentistry is extensive dental procedures that require pulpal anesthesia beyond 90 min and management of postoperative pain. Ropivacaine is an amide local anesthetic that is available at various concentrations with inherent vasoconstrictive properties at low concentrations. Ropivacaine has a 75% greater margin of safety than bupivacaine. Ropivacaine can be a good alternative to bupivacaine as a local anesthetic in dental implant surgery as it provides a longer duration of both pulpal and soft tissue anesthesia after mandibular nerve block and lowers CNS and cardiovascular toxicity. This study aimed to evaluate and compare the clinical efficacy of ropivacaine and lignocaine for implant surgery anesthesia. Methods: Fifteen patients with bilateral edentulous sites indicated for implant placement were recruited for this study. Patients aged 20-60 years of both sexes were randomly recruited. Thirty implant placements were performed in the test and control groups using ropivacaine and lignocaine with adrenaline as local anesthetics, respectively. Results: The results were analyzed statistically. The duration of anesthesia was significantly higher in the test group than in the control group. Ropivacaine was found to be superior to lignocaine in terms of the quality of anesthesia. The comparison of mean visual analog scale scores showed ropivacaine to have better anesthetic and analgesic effects than the control group. Conclusion: Ropivacaine 0.75% provides a significantly longer duration of anesthesia than lignocaine 2% with adrenaline. Ropivacaine 0.75% decreased intraoperative and postoperative analgesia compared to lignocaine 2% with adrenaline. Hence, ropivacaine 0.75% can be used as an alternative to lignocaine in implant surgeries and other intraoral surgical procedures that require a longer duration of anesthesia and analgesia.

• Restorative Dentistry and Endodontics
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• v.49 no.1
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• pp.2.1-2.12
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• 2024

Objectives: This study aimed to determine the effects of 1-rooted mandibular second molar (MnSM) teeth on root canal anatomy complexities of the mandibular central incisor (MnCI), mandibular lateral incisor (MnLI), mandibular canine (MnCn), mandibular first premolar (MnFP), mandibular second premolar (MnSP), and mandibular first molar (MnFM) teeth. Materials and Methods: Cone-beam computed tomography images of 600 patients with full lower dentition were examined. Individuals with 1-rooted MnSMs were determined, and the complexity of root canal anatomy of other teeth was compared with individuals without 1-rooted MnSMs (Group-1; subjects with at least one 1-rooted MnSM, Group-2; subjects with more than a single root in both MnSMs). A second canal in MnCIs, MnLIs, MnCns, MnFPs, and MnSPs indicated a complicated root canal. The presence of a third root in MnFMs was recorded as complicated. Results: The prevalence of 1-rooted MnSMs was 12.2%, with the C-shaped root type being the most prevalent (9%). There were fewer complicated root canals in MnCIs (p = 0.02), MnLIs (p < 0.001), and MnFPs (p < 0.001) in Group 1. The other teeth showed no difference between the groups (p > 0.05). According to logistic regression analysis, 1-rooted right MnSMs had a negative effect on having complex canal systems of MnLIs and MnFPs. Left MnSMs were explanatory variables on left MnLIs and both MnFPs. Conclusions: In individuals with single-rooted MnSMs, a less complicated root canal system was observed in all teeth except the MnFMs.

• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.157-163
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• 2008

Formation of ${\beta}$-amyloid $(A{\beta})$ fibrils has been identified as one of the major characteristics of Alzheimer's disease (AD). Inhibition of $A{\beta}$ fibril formation in the CNS would be attractive therapeutic targets for the treatment of AD. Several small compounds that inhibit amyloid formation or amyloid neurotoxicity in vitro have been known. Citrate has surfactant function effect because of its molecular structure having high anionic charge density, in addition to the well-known antibacterial and antioxidant properties. Therefore, we hypothesized that citrate might have the inhibitory effect against $A{\beta}$ fibril formation in vitro and have the protective effect against $A{\beta}$-induced neurotoxicity in PC12 cells. We examined the effect of citrate against the formation of $A{\beta}$ fibrils by measuring the intensity of fluorescence in thioflavin-T (Th-T) assay of between $A{\beta}_{25-35}$ groups treated with citrate and the control with $A{\beta}_{25-35}$ alone. The neuroprotective effect of citrate against $A{\beta}$-induced toxicity in PC12 cells was investigated using the WST-1 assay. Fluorescence spectroscopy showed that citrate inhibited dose-dependently the formation of $A{\beta}$ fibrils from ${\beta}$-amyloid peptides. The inhibition percentages of $A{\beta}$ fibril formation by citrate (1, 2.5, and 5 mM) were 31%, 60%, and 68% at 7 days, respectively in thioflavin-T (Th-T) assay. WST-1 assay revealed that the toxic effect of $A{\beta}_{25-35}$ was reduced, in a dose-dependent manner to citrate. The percentages of neuroprotection by citrate (1, 2.5, and 5 mM) against $A{\beta}-induced$ toxicity were 19%, 31 %, and 34%, respectively. We report that citrate inhibits the formation of $A{\beta}$ fibrils in vitro and has neuroprotective effect against $A{\beta}$-induced toxicity in PC12 cells. Neuroprotective effects of citrate against $A{\beta}$ might be, to some extent, attributable to its inhibition of $A{\beta}$ fibril formation. Although the mechanism of anti-amyloidogenic activity is not clear, the possible mechanism is that citrate might have two effects, salting-in and surfactant effects. These results suggest that citrate could be of potential therapeutic value in Alzheimer's disease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.125-131
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• 1976

To study the effects of temperature, day length, and various plant growth regulator treatments on the tuber formation of Irish cobbler, this experiment was carried out with 2 combinations of day-length and temperature and 11 kinds of growth regulator, including GA, and their combinations. For the tuber formation, low temperature-short day condition played decisive role, and exceeded the effects of growth regulators. 4 times foliar application of 10 ppm GA resulted marked elongation of stolon but did not inhibit the tuber formation even under high temperature longday condition.

• Journal of Venture Innovation
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• v.4 no.1
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• pp.67-86
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• 2021

The purpose of this study was to examine the effects of office workers' covert narcissism on organizational silence and identify the (Duel)mediation effects on fear of negative evaluation and the avoidance motivation. This study used a survey of 393 office workers to measure the covert narcissism, the organizational silence, the fear of negative evaluation and the avoidance motivation. The collected data were analyzed by IBM SPSS 23 and SPSS PROCESS macro in a Bootstrapping method. The result shows that the covert narcissism, the organizational silence, the fear of negative evaluation and the avoidance motivation have positive correlations. In addition, a simple regression analysis was used according to the research model and all of them showed adequate coefficient of determination between each variables. Next, the mediating model was verified by mediation of the fear of negative evaluation and the avoidance motivation. In the relationship between the covert narcissism and the organizational silence, the mediating effect of the fear of negative evaluation was not verified and the avoidance motive showed a partial mediating effect. Finally, in the relationship between the covert narcissism and the organizational silence, the fear of negative evaluation and the avoidance motivation were gradually mediated through the (Duel)mediation effects model, and the model was statistically significant. Through this study, The implications of this study were discussed, not only the limitations of the study but also the necessity of further research were discussed.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.81-90
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• 1998

Electromagnetic waves may induce various effects on nervous tissues either by thermal or non-thermal mechanisms. This paper intoduces a method to evalute the non-thermal effect to central nervous system by measuring the EEGs of the rabbits treated by nimodipine before exposed to weak microwave field. 20 rabbits were divided into 2 groups and their EEGs were measured after their head section were exposed to 2,450 MHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of the 3rd group of 10 rabbits which were not exposed. The 4th group of 10 rabbits were intravenously given with nimodipine before exposed to 20 dBm field to determine whether this drug would reverse the EEGs changes induced by weak microwave irradiation. As field poser exceeded 20 dBm although no significant physiological changes were observed, total induced EEGs power was remarkably decreased suggesting the presence of CNS activation. Using Fourier analysis on the EEGs signal it was found that remarkable decrease in delta band and increase in the alpha and beta bands in a significant manner(P<0.05) compared to control group. The changes were, however, not reversed by nimodipine-treatment. The effects may be pure thermal in nature because no significant change has been observed in nimodipine treated rabbits.

• Archives of Pharmacal Research
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• v.24 no.1
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• pp.64-68
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• 2001

Endothelin-1 (ET-1 ), a novel and potent vasoconstrictor in blood vessel, is known to have some functions in the rat central nervous system (CNS), In order to investigate the central functions of ET-1 , ET-1 was administered to the periaqueductal gray area (PAC) of anesthetized rats to induce barrel rolling and increase the arterial blood pressure (ABP). ET-1 had a modulatory effect on central cardiovascular and behavioral control. The selective N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (3${u}m/ol/kg$, i.p.) blocked the ET-1 induced responses, and both the nitric oxide synthase (NOS) inhibitor L-NAME (N-nitro-L-arginine mIThyl-ester 1 nmol/rat) and the nitric oxide (NO) scavenger hemoglobin (15 nmol/rat) had similar effects in redtAcing the IT-1 (10 pmol/rat)-induced behavioral changes and ABP elevation. However, NO donor sodium nitroprusside (SNP 10${u}g$, 1${u}g/rat$) decreased the ET-1 induced ABP elevation, and recovered the ET-1 -induced barrel rolling effect that was reduced by MK-801. These results suggest that ET-1 might have neuromodulatory functions such as ABP elevation and barrel rolling induction in the PAG of the rats via the NMDA receptor and NO.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.1
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• pp.159-168
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• 2020

Purpose : To provide data on exercise prescription for obesity management and prevention of cardiovascular disease in girl's high school and to prepare basic data for more effective exercise program for lifestyle improvement and prevention of lifestyle-related diseases. This study examines the effects on brain nerve growth factor and inflammatory factors, and the relationship between obesity factor and brain neuron cell production factor and inflammatory factor changes by complex exercise. Methods : The subjects of the study were obese students with a body fat percentage of 30 % or higher after obtaining body fat percentage of high school girls in C-city. Among them, 20 students who wanted to participate in the program of this study and did not participate in special exercise and diet therapy within the last 6 months were radio-sampled into groups of exercise group and control group, but attendance rate was low and The final exercise group (9) and control group (9) were measured, except for one student who did not respond. Results : Analysis of the range of variation in body composition, BMI, lean body mass, and the interaction between the groups showed significant differences (p<.05). TC, TG, HDL-C, and LDL-C as variables of blood lipids, TC and TG were not significantly different and TG was significantly different (p<.05) in interactions. HDL-C showed a significant difference (p<.01) in interactions, an increase in exercise group, and a significant decrease in control group (p<.05). There was a significant difference (p<.05) in BDNF interaction, an increase in the exercise group and a decrease in the control group, but no significant difference. NGF tended to increase in both exercise and control groups. IL-6 had a significant difference in timing (p<.05) and significantly decreased (p<.01) in the exercise group, and TNF-α interacted with timing (p<.05), and a significant increase in the control group. Conclusion : This study confirmed 12-week compound exercise program was effective in increasing the expression of basal fitness or CNS factor, but not enough to actually improve brain function. Fat mass and obesity are also affecting vascular inflammatory factors.

• The Korean Journal of Pharmacology
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• v.31 no.2
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• pp.153-164
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• 1995

Sympathomimetic amines, especially ephedrine, are a major ingredient in proprietary medications for symptomatic treatment of upper respiratory infections. Their frequent uses can lead to occasional instances of abuse and habituation. The clinical symptoms of ephedrine abuse are similar to that of amphetamine psychosis and resemble closely that of schizophrenia. Because both amphetamine psychosis and schizophrenia are thought to be mediated primarily through the action on catecholamines, ephedrine-induced changes of the biogenic amines can be suspected. However, there were few studies about the central effects of ephedrine because of the milder central action than peripheral. Therefore, the present investigation was undertaken to elucidate the relations between the effects of single or repeated administration of ephedrine on the regional levels of biogenic amines in rat brain and ephedrine-induced CNS stimulation. The male Sprague-Dawley rats weighing $100{\sim}200\;g$ were used. After single or repeated administrations of ephedrine, blocks of tissue were obtained from frontal cortex, corpus striatum, hippocampus, thalamus, hypothalamus, substantia nigra and cerebellum. The concentration of biogenic amines(norepinephrine, epinephrine, dopamine, 5-hydroxytryptamine(5-HT)) and their metabolites (3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid(HVA), 5-hydroxyindoleacetic acid(5-HIAA)) were measured by means of high performance liquid chromatography-electrochemical detector(HPLC-ECD). The results obtained were as follows: 1) In the normal rat, the concentration of norepinephrine was the highest in hypothalamus. Dopamine, DOPAC and HVA were highest in corpus striatum, and 5-HT and 5-HIAA were highest in substantia nigra. Epinephrine was not detectable in any part of the brain tissue. 2) In a single administration of ephedrine, the concentration of DOPAC was decreased in corpus striatum. However, the other biogenic amines and their metabolites were not changed. 3) In repeated administration of ephedrine, the concentration of norepinephrine was decreased in all brain region checked. Dopamine was decreased in corpus striatum and substantia nigra and, increased in hypothalamus, and HVA was decreased in corpus striatum. 5-HT was decreased in all brain region except cerebellum and, 5-HIAA was decreased only in frontal cortex. The ratio of 5-HIAA/5-HT was increased in corpus striatum, thalamus, hypothalamus and substantia nigra. These data indicated that, although a single administration of ephedrine did not change the central neurotransmitters, repeated administration of ephedrine caused the decreases of norepinephrine and 5-HT in the most regions of brain, which may be responsible for the emergence of abnormal behavioral effect after ephedrine abuse.