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  • Author or Editor: Jin Kim x
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Background and aims

Overindulgence in Internet gaming, which is related to rapid development of the online game industry, can cause a psychiatric disorder known as Internet gaming disorder (IGD). The number of adolescents with IGD is on the rise in countries with developed Internet technologies, such as South Korea. Therefore, it is important to develop biomarkers to detect patients at high risk of IGD. This study investigated expression levels of proteins in the blood of adolescents to provide insight into the development of biomarkers.

Methods

We collected blood samples from 73 subjects [40 healthy adolescents (Internet gaming control, IGC) and 33 adolescents with IGD] between 13:00 and 15:00. We analyzed the expression levels of orexin A, oxytocin, cortisol, melatonin, BDNF, sICAM-1, RANTES, and NCAM using multiplex assay kits.

Results

Orexin A was significantly (p = .016) elevated in the IGD group and the expression levels of melatonin tended to be higher (p = .055) in the IGD group. On the other hand, increased Internet gaming time in the IGD group was negatively correlated (p = .041) with expression of BDNF. On the contrary, sICAM-1 associated with inflammation exhibited the tendency of the positive correlation (p = .073) with Internet gaming time in the IGD group.

Discussion and conclusions

We identified elevation of orexin A in the peripheral blood of adolescents with IGD and a negative correlation between Internet gaming time and BDNF in adolescents with IGD. Our results provide useful information to understand the pathophysiology of IGD in adolescents.

Open access
Reaction Kinetics, Mechanisms and Catalysis
Authors: Jung-Nam Park, Jeong Kuk Shon, Mingshi Jin, Soo Sung Kong, Kiyoung Moon, Gwi Ok Park, Jin-Hyo Boo and Ji Man Kim

Abstract

Highly ordered mesoporous ruthenium dioxide (meso-RuO2) has been successfully synthesized by controlling the surface hydrophobicity of a mesoporous silica template (KIT-6) via a nano-replication method. The meso-RuO2 material, thus obtained, exhibits a well-defined mesostructure and high surface area (131 m2 g−1). The physicochemical properties of the meso-RuO2 material are characterized by electron microscopy, X-ray diffraction, N2 adsorption–desorption, temperature programmed techniques, and X-ray photoelectron spectroscopy. Pretreatment of the meso-RuO2 catalyst under different gas environments (O2, H2 and CO) strongly affects the catalytic activity towards CO oxidation. The meso-RuO2, pretreated by O2 flowing at 200 °C, exhibited excellent catalytic activity for CO oxidation, 100% CO conversion with long-term stability at room temperature, whereas the meso-RuO2 catalysts with pretreatment under other conditions are not very active at room temperature. It is found that the surface oxygen species generated on the meso-RuO2 during O2 pretreatment at 200 °C provide CO oxidation activity at room temperature.

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Abstract

During the process of fermentation, the chemical compositions of trifoliate orange (Poncirus trifoliate (L). Raf) changed greatly. To provide a completely phytochemical profile, high-performance liquid chromatography-diode array detector-hyphenated with tandem mass spectrometry (HPLC–DAD–ESI-MS/MS) has been successfully applied to screen and identify the unknown constituents of trifoliate orange during fermentation, which make it available for the quality control of fermented products. Multivariate statistical analysis was performed to classify the trifoliate oranges based on the status of fermentation. A total of 8 components were identified among the samples. Hierarchical Clustering Analysis (HCA) and Principal Component Analysis (PCA) demonstrated the fermented and unfermented trifoliate oranges were obviously different, an effective and reliable Partial Least Square Discriminate Analysis (PLS-DA) technique was more suitable to provide accurate discrimination of test samples based their different chemical patterns. Furthermore, a permutation validated the reliability of PLS-DA and variable importance plot revealed that the characterized syringing, naringin, and poncirin showed the high ability to distinguish the trifoliate oranges during fermentation. The present investigation could provide detailed information for the quality control and evaluation of trifoliate oranges during the fermentation process.

Open access
Journal of Behavioral Addictions
Authors: Sam-Wook Choi, Dai-Jin Kim, Jung-Seok Choi, Heejune Ahn, Eun-Jeung Choi, Won-Young Song, Seohee Kim and Hyunchul Youn

Background and Aims

Smartphone addiction is a recent concern that has resulted from the dramatic increase in worldwide smartphone use. This study assessed the risk and protective factors associated with smartphone addiction in college students and compared these factors to those linked to Internet addiction.

Methods

College students (N = 448) in South Korea completed the Smartphone Addiction Scale, the Young’s Internet Addiction Test, the Alcohol Use Disorders Identification Test, the Beck Depression Inventory I, the State–Trait Anxiety Inventory (Trait Version), the Character Strengths Test, and the Connor–Davidson Resilience Scale. The data were analyzed using multiple linear regression analyses.

Results

The risk factors for smartphone addiction were female gender, Internet use, alcohol use, and anxiety, while the protective factors were depression and temperance. In contrast, the risk factors for Internet addiction were male gender, smartphone use, anxiety, and wisdom/knowledge, while the protective factor was courage.

Discussion

These differences may result from unique features of smartphones, such as high availability and primary use as a tool for interpersonal relationships.

Conclusions

Our findings will aid clinicians in distinguishing between predictive factors for smartphone and Internet addiction and can consequently be utilized in the prevention and treatment of smartphone addiction.

Open access
Journal of Behavioral Addictions
Authors: Seung-Yup Lee, Donghwan Lee, Cho Rong Nam, Da Yea Kim, Sera Park, Jun-Gun Kwon, Yong-Sil Kweon, Youngjo Lee, Dai Jin Kim and Jung-Seok Choi

Background and objectives

The ubiquitous Internet connections by smartphones weakened the traditional boundaries between computers and mobile phones. We sought to explore whether smartphone-related problems differ from those of computer use according to gender using latent class analysis (LCA).

Methods

After informed consents, 555 Korean middle-school students completed surveys on gaming, Internet use, and smartphone usage patterns. They also completed various psychosocial instruments. LCA was performed for the whole group and by gender. In addition to ANOVA and χ2 tests, post-hoc tests were conducted to examine differences among the LCA subgroups.

Results

In the whole group (n = 555), four subtypes were identified: dual-problem users (49.5%), problematic Internet users (7.7%), problematic smartphone users (32.1%), and “healthy” users (10.6%). Dual-problem users scored highest for addictive behaviors and other psychopathologies. The gender-stratified LCA revealed three subtypes for each gender. With dual-problem and healthy subgroup as common, problematic Internet subgroup was classified in the males, whereas problematic smartphone subgroup was classified in the females in the gender-stratified LCA. Thus, distinct patterns were observed according to gender with higher proportion of dual-problem present in males. While gaming was associated with problematic Internet use in males, aggression and impulsivity demonstrated associations with problematic smartphone use in females.

Conclusions

An increase in the number of digital media-related problems was associated with worse outcomes in various psychosocial scales. Gaming may play a crucial role in males solely displaying Internet-related problems. The heightened impulsivity and aggression seen in our female problematic smartphone users requires further research.

Open access

A number of essential oils from citrus peels are claimed to have biological activities. Citrus peel, called ‘Jin-Pi’, is used in traditional medicine for digestion, severe cold, and fever. However, the antibacterial activities against skin pathogens and anti-inflammatory effects of the essential oils of Citrus sunki (JinGyul) and Fortunella japonica var. margarita (GumGyul) have not yet been described. Therefore, in this study, the essential oils of the citrus species C. sunki (CSE) and F. japonica var. margarita (FJE), both native to the island of Jeju, Korea, were examined for their anti-inflammatory and antimicrobial activities against skin pathogens. Four human skin pathogenic microorganisms, Staphylococcus epidermidis CCARM 3709, Propionibacterium acnes CCARM 0081, Malassezia furfur KCCM 12679, and Candida albicans KCCM 11282, were studied. CSE and FJE exhibited strong antimicrobial activity against most of the pathogenic bacteria and yeast strains that were tested. Interestingly, CSE and FJE even showed antimicrobial activity against antibiotic-resistant S. epidermidis CCARM 3710, S. epidermidis CCARM 3711, P. acnes CCARM9009, and P. acnes CCARM9010 strains. In addition, CSE and FJE reduced the lipopolysaccharide (LPS)-induced secretion of nitric oxide (NO) in RAW 264.7 cells, indicating that they have anti-inflammatory effects. We also analysed the chemical composition of the oils by gas chromatography-mass spectrometry (GC-MS) and identified several major components, including dl-limonene (68.18%) and β-myrcene (4.36%) for CSE, and dl-limonene (61.58%) and carvone (6.36%) for FJE. Taken together, these findings indicate that CSE and FJE have great potential to be used in human skin health applications.

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Reaction Kinetics, Mechanisms and Catalysis
Authors: Bo-Hyun Kim, Tae-Hee Lim, Jin-Woong Roh, Sang-Geun Lee, Chang Ju, Seong Park, Seong Hong and Gun Lee

Abstract  

Undoped and Cr-doped Bi12TiO20 (BTO) were prepared and used as photocatalysts for the degradation of formic acid both under visible light and UV irradiation. The effects of the Cr doping on the visible light response and the photocatalytic activity of BTO were investigated. The prepared catalysts were characterized by using XRD, XPS, UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The doping of Bi12TiO20 with low concentration of Cr leads to noticeable increase in visible light absorption and decrease in the recombination rate of photo-generated electrons and holes. As a result, the Cr-doped BTO showed a higher photocatalytic activity for the degradation of formic acid both under visible light and UV irradiation, as compared with undoped BTO.

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Abstract  

Instrumental neutron activation analysis was used for the analysis of 25 trace elements in airborne particulate matter (PM) for air pollution monitoring. For the collection of air samples, the Gent stacked filter unit low volume sampler and two types of Nuclepore polycarbonate filters were employed. Samples were collected at selected sampling dates in suburban and industrial regions of Daejon city in the Republic of Korea. Mass concentrations and black carbon of PM were measured, and enrichment factors were calculated. The results were used to describe the emission sources and their correlation patterns.

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Abstract  

The spontaneous reduction of Eu3+ to Eu2+ was examined when EuCl3 was added into a pyroprocessing media of LiCl molten salt at 923 K. The amount of Eu2+ was calculated by measuring the total charge consumed to oxidize Eu2+ ions to Eu3+ ions. The concentration ratio of Eu2+ to Eu3+ was estimated to be about 0.40 in the media. In addition, it is confirmed that the reduction of Eu3+ to Eu2+ is caused by the oxidation power of Cl to Cl2. The coexistence of Eu3+ and Eu2+ in the LiCl molten salt system was examined by UV–Visible and luminescence spectroscopy. The molar absorptivities of Eu3+ and Eu2+, calculated from UV–Visible absorption spectra, were 423 and 1954 M−1 cm−1, respectively.

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Abstract

Platinum catalysts supported on silicas with various physicochemical properties were prepared in order to investigate the effect of silica characteristics on their platinum dispersion and catalytic activity in the oxidation of carbon monoxide. Although titania-incorporation into silica and further treatment of the impregnated platinum precursor with hydrogen peroxide were effective for improving the dispersion and stability of platinum catalysts supported on silicas, regardless of the characteristic of the silicas, the platinum catalysts supported on fumed silica with a medium level of surface hydroxyl group concentration exhibited the highest catalytic activity among those supported on mesoporous silica, silica gel, and precipitated silica. The required properties of the highly active platinum catalyst seemed to be a high dispersion of platinum, the formation of a stable titania layer, and the generation of strong acid sites. By contrast, the precipitated silica with a small surface area and high concentration of surface hydroxyl groups was not appropriate for a catalytic support for platinum catalysts.

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