• Polymer(Korea)
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• v.35 no.4
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• pp.350-355
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• 2011

A soluble polyamide containing photosensitive l,4-phenylenediacrylic acid (PDA) in main chain with biphenyl moiety was synthesized. The chemical structure of synthesized polyamide was investigated by means of $^1H$ NMR spectroscopy. The polymer was stable up to $280^{\circ}C$ and soluble in organic solvents, giving a good quality of thin films. The photoreaction of unpolarized LTV irradiated films was investigated by means of UV-vis absorption spectroscopy and FTlR spectroscopy, and liquid crystals (LCs) alignment property was examined by exposing to linearly polarized UV light (LPUVL) of 260~380 nm. The polyamide in film has excellent photoreactivity to unpolarized UV light. Direction selective photoreaction of PDA moiety in Lhe film was found to further induce nematic liquid -crystals to align along a perpendicular direction with respect to the electric vector of LPUVL, regardless of exposure energy of LPUVL. In addition, pretilt angle was measured by means of crystal rotation method. LPUVL-exposed polymer film induced the alignment of liquid-crystals (LC) with a pretilt angle of 0.2~$0.5^{\circ}$.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.87-94
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• 2017

Purpose: The inappropriate prescription of antibiotics in children with upper respiratory tract infection (URTI) is common. This study evaluated the factors that influence antibiotics use in hospitalized children with viral URTI confirmed by reverse transcriptase-polymerase chain reaction (RTPCR) assay. Methods: The medical records of admitted patients who performed RT-PCR assay for respiratory virus pathogens from January 2013 to November 2014 were examined. The demographic and clinical features were compared between patients who were administered antibiotics at admission and those who were not. We also investigated differences between children who continued antibiotics and those who stopped antibiotics after a viral pathogen was identified. Results: In the total 393 inpatients, the median age was 23 months (interquartile range, 13 to 41.3 months). Antimicrobial agents were prescribed in 79 patients (20.1%) at admission. Patients with acute otitis media (AOM) had higher rates of antibiotics prescription than those without AOM (48.1% vs. 2.2%, P<0.001), with an adjusted odds ratio of 91.1 (95% confidence interval, 30.5 to 271.7). Level of high-sensitivity C-reactive protein and the proportion of acute rhinosinusitis were also significantly associated with antibiotics use (P<0.001). Among the 44 patients with viruses identified using the RT-PCR method during hospitalization, antibiotic use was continued in 28 patients (63.6%). AOM was statistically associated with continued antibiotic use in the patients (P=0.002). Conclusions: Although the respiratory virus responsible for URTI etiology is identified, clinicians might not discontinue antibiotics if AOM is accompanying. Therefore, careful diagnosis and management of AOM could be a strategy to reduce unjustified antibiotic prescriptions for children with URTI.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.524-528
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• 2002

The study was carried out to evaluate the antioxidant activity of grape seed extracts by measuring acid value, peroxide value (POV), thiobarbituric acid reactive substances (TBARS value) and electron donating ability by 1,1-dipheny1-2-pycryl hydrazil (DPPH) method. Total phenol content of freeze dried crude solvent extracts increased in the order of ethanol>acetone>hot water. Among extracts, the total phenol content of 70% ethanol extract of grape seed (GSE) was the highest, 51%. Besides the total phenol, the other major components of GSE were crude carbohydrate (29.63%), crude protein (3.38%) and crude lipid (2.84%). The acid values of crude rice bran oil containing GSE or several antioxidants at the concetration of 0.01% were 52.3 for the control, 0.5 for GSE, 2.3 for dibutyl hydroxytoluene (BHT), 45.0 for tertiarybutyl hydroxy quinone (TBHQ), 29.9 for tocopherol and 37.7 for ascorbic acid. The POVs for linoleic acid methyl ester in the presence of 0.01% antioxidants were 1220 meq/kg in control, 55 meq/kg in GSE, 104 meq/kg in BHT, 952 meq/kg in tocopherol and 71 meq/kg in GSE, 37% in BHT, 37% in tocopherol and 52% in ascorbic acid. The electron donating abilities by DPPH in the presence of 0.01% antioxidants were 95.3% in GSE, 75.0% in BHT, 96.3% in tocopherol and 98.2% in ascorbic acid. These results indicated that the antioxidants activities of GSE were significantly higher than those of several antioxidants compared.

• Food Science and Preservation
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• v.24 no.3
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• pp.325-333
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• 2017

This study aimed to investigate the various biological activities of Geranium thunbergii such as antimicrobial activity and protective effect against oxidative damage. To evaluate its antioxidant and antimicrobial activities, we first performed methanol extraction; this methanol extract was further partitioned using various solvents. And then, its antioxidant activity was measured using various assays including total phenolic content and protection against oxidative DNA damage, and antimicrobial activities were examined using minimum inhibiting concentration (MIC) test, and paper disc method. In addition, high-performance liquid chromatography was performed to analyze the major chemical components of ethyl acetate fraction. The G. thunbergii fraction with ethyl acetate exhibited higher antioxidant and antimicrobial activities than the other fractions. The results showed that G. thunbergii ethyl acetate fraction at $50{\mu}g/mL$ had strong DPPH and ABTS radical scavenging activities of 80.88% and 80.12%, respectively. In addition, the ethyl acetate fraction protected DNA from the oxidative damage induced by ferrous ion and hydroxyl radicals and showed high antimicrobial activity with diameter of inhibition zones ranging from 13.33 to 15.67 mm. High-performance liquid chromatography analysis revealed the major phenolic compounds of G. thunbergii to be ellagic acid and gallic acid. These results suggest that G. thunbergii might protect DNA against oxidative stress induced by reactive oxygen species and can be utilized as a natural source of antioxidant and antimicrobial agent in the food industry.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.357-364
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• 2018

Fly ash is a material used as a concrete admixture. When fly ash is used for concrete manufacturing, it is expected to improve the performance such as reduction of cement usage and increase of chemical resistance. However, fly ash have some problems such as unburned carbon content and amorphous film on the surface of fly ash particles. When concrete is manufactured using fly ash containing a large amount of unburned carbon, there is a problem that the slump is lowered due to adsorption of AE agent. In addition, the amorphous film on the surface of the particles prevents the reactive substances from leaching out of the fly ash. Therefore, a method of surface treatment of fly ash using plasma has been studied to remove such unburned carbon and amorphous films. However, plasma has the problem that $O_3$ is generated when $O_2$ is used as an active gas. $O_3$ is a harmful substance and adversely affects the health of the experimenter. In this study, the surface of fly ash was treatment by arc discharge. Experimental results show that the unburned carbon is removed when the surface of fly ash is treatment by arc discharge and the amorphous film was broken and the reactivity was improved. Therefore, it is considered that arc discharge can treatment the surface of fly ash and improve the quality of fly ash.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.398-406
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• 2022

The outer membrane of Gram-negative bacteria is the outermost layer of cellular environment in which numerous biophysical and biochemical processes are in action sustaining viability. Advances in cell engineering enable modification of bacterial genetic information that subsequently alters membrane physiology to adapt bacteria to specific purposes. Surface display of a functional molecule on the outer membranes is one of strategies that directs host cells to respond to a specific extracellular matter or stimulus. While intracellular expression of a functional peptide or protein fused to a membrane-anchoring motif is commonly practiced for surface display, the method is not readily applicable to exogenous or large proteins inexpressible in bacteria. Chemical conjugation at reactive groups naturally occurring on the membrane might be an alternative, but often compromises fitness due to non-specific modification of essential components. Herein, we demonstrated two distinct approaches that enable site-specific decoration of the outer membrane with a fluorescent agent in Escherichia coli. An unnatural amino acid genetically incorporated in a surface-exposed peptide could act as a chemoselective handle for bioorthogonal dye labeling. A surface-displayed α-helical domain originating from a part of a selected heterodimeric coiled-coil complex could recruit and anchor a green fluorescent protein tagged with a complementary α-helical domain to the membrane surface in a site- and hetero-specific manner. These methods hold a promise as on-demand tools to confer new functionalities on the bacterial membranes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.144-157
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• 2022

Noble gases, which are chemically inert and behave conservatively in marine environments, have been used as tracers of physical processes such as air-sea gas exchange, mixing of water masses, and distribution of glacial meltwater in the ocean. For precise measurements of Ne, Ar, and Kr, we developed a mass spectrometric system consisting of a quadrupole mass spectrometer (QMS), a high vacuum preparation line, an activated charcoal cryogenic trap (ACC), and a set of isotope standard gases. The high vacuum line consists of three sections: (1) a sample extraction section that extracts the dissolved gases in the sample and mixes them with the standard gases, (2) a gas preparation section that removes reactive gases using getters and separates the noble gases according to their evaporation points with the ACC, and (3) a gas analysis section that measures concentrations of each noble gas. The ACC attached to the gas preparation section markedly lowered the partial pressures of Ar and CO₂ in the QMS, which resulted in a reduced uncertainty of Ne isotope analysis. The isotope standard gases were prepared by mixing ²²Ne, ³⁶Ar, and ⁸⁶Kr. The amounts of each element in the mixed standard gases were determined by the reverse isotope dilution method with repeated measurements of the atmosphere. The analytical system achieved precisions for Ne, Ar, and Kr concentrations of 0.7%, 0.7%, and 0.4%, respectively. The accuracies confirmed by the analyses of air-equilibrated water were 0.5%, 1.0%, and 1.7% for Ne, Ar, and Kr, respectively.

• Journal of Korean Medicine Rehabilitation
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• v.33 no.2
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• pp.1-18
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• 2023

Objectives The purpose of this study was to evaluate the antioxidant, anti-inflammatory and wound healing effects of Samul-tang-ga-dansam water extract (SD) in wound-induced mice. Methods The mice were divided into five groups (n=7): the normal group, the control group, the positive control group, the low-dose SD group and the high-dose SD group. The normal group had no wounds and the other groups were wounded on the back with a leather punch. Distilled water was administered to the control group, 200 mg/kg of vitamin E was administered to the positive control group. In the low-dose SD group and the high-dose SD group, 1.23 g/kg and 2.47 g/kg of SD were administered, respectively. Antioxidant and anti-inflammatory protein levels were evaluated using western blot analysis. Skin tissue was analyzed by H&E, Masson's trichrome staining method. Results Oral administration of the SD significantly reduced the visible skin damage and decreased the reactive oxygen species and ONOO^- activity of the serum. It significantly increased heme oxygenase-1, superoxide dismutase, catalase, GPx-1/2, Nrf2 and Keap-1 which are antioxidant-related factors in skin tissue and reduced NF-κB p65, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor α, interleukin (IL)-1β, IL-6 which are inflammation-related factors. Also, SD significantly decreased NOX2, p22^phox and p47^phox and increased α-smooth muscle actin and COL1A1 protein expression in fibroblasts involved in connective tissue repair. According to histological examination, the thickened epithelial layer was thinned and collagen fibers were increased to accelerate wound healing. Conclusions It is suggested that Samul-tang-ga-dansam has antioxidant and anti-inflammatory effects and promotes wound tissue repair.

• Fisheries and Aquatic Sciences
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• v.25 no.11
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• pp.579-586
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• 2022

Research on the potential biological activity of red alga Symphyocladia spp. has been limited to Symphyocladia latiuscula, which is widely used as a food ingredient in Korea. Here, we examined the biological activity of another species, Symphyocladia linearis, which is found in Korea and was reported as a new species in 2013. The aim of this study was to evaluate the antioxidant, anti-inflammatory, and antibacterial properties of a 70% ethanol extract of S. linearis. Antioxidant activity, which was evaluated using radical scavenging assays, revealed half maximal inhibitory concentration values for 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) of 34.57 and 11.70 ㎍/mL algal extract, respectively. Anti-inflammatory activity of the S. linearis ethanolic extract was evaluated using RAW 264.7 cells by measuring the inhibition of lipopolysaccharide-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production. The potential cytotoxicity of NO and PGE₂ was first examined, confirming no toxicity at concentrations ranging from 10-100 ㎍/mL. NO production was inhibited 61.1% and 78.0% at 50 and 100 ㎍/mL S. linearis extract, respectively; and PGE₂ production was inhibited 69.1%, 83.2%, and 94.8% at 25, 50, and 100 ㎍/mL S. linearis extract, respectively. Thus, the S. linearis extract showed very strong efficacy against PGE₂ production. The cellular production of reactive oxygen species, measured using 2',7'-dichlorofluorescin diacetate fluorescence, was inhibited 48.8% by the addition of 100 ㎍/mL S. linearis extract. Antibacterial activity was evaluated using the disc diffusion method and minimum inhibitory concentration (MIC). S. linearis was effective only against gram-positive bacteria, exhibiting antibacterial activity against Staphylococcus aureus with a MIC of 256 ㎍/mL extract and against Bacillus cereus with a MIC of 1,024 ㎍/mL extract. Based on these results, we infer that a 70% ethanolic extract of S. linearis possesses strong anti-inflammatory properties, and therefore has the potential to be used in the prevention and treatment of inflammatory and immune diseases.

• Korean Journal of Social Welfare Studies
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• v.42 no.2
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• pp.467-491
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• 2011

The purpose of this study is to examine relationship between social strains such as status strains and relational strains and adolescent suicidality by gender. As method, a self-report survey was completed by students (n = 819) from 3 middle schools in Seodaemun area, Seoul, Korea. Logistic regression analyses were conducted to identify factors associated with adolescent suicidality, t-test analyses were used to verify gender difference. Results show that male adolescents are more likely to experience abuse from their father, and school violence related to relational strains than female. Differences were found in strains for males and females contributing to suicidality; male are responsive to economic status, a dimension of status strain, whereas female are reactive to non-physical abuse from father, a type of relational strains. Non-physical school violence was appeared to be a significant factor influencing suicidality for both genders. Based on these findings, research draws implications for social work interventions. First, different approaches by gender are needed to prevent adolescent suicide in consideration of the tendency that men are status-oriented and women are relationship-oriented. Second, it is suggested to hire full-time school social worker to provide consistent social service for students. Third, intensive effort is necessary to reduce non-physical school violence.