• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.43.1-43.12
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• 2023

Background: Gig workers, also known as platform workers, are independent workers who are not employed by any particular company. The number of gig economy workers has rapidly increased worldwide in the past decade. There is a dearth of occupational health studies among gig economy workers. We aimed to investigate the association between exposure to violence and job stress in gig economy workers and depressive symptoms. Methods: A total of 955 individuals (521 gig workers and 434 general workers) participated in this study and variables were measured through self-report questionnaires. Depressive symptoms were evaluated by the Patient Health Questionnaire-9 when the score was greater than or equal to 10 points. The odds ratio with 95% confidence interval was calculated using multivariable logistic regression adjusted for age, sex, working hours, education level, exposure to violence and job stress. Results: 19% of gig economy workers reported depressive symptoms, while only 11% of general workers reported the depressive symptoms. In association to depressive symptoms among gig economy workers, the mainly result of odds ratios for depressive symptoms were as follows: 1.81 for workers type, 3.53 for humiliating treatment, 2.65 for sexual harassment, 3.55 for less than three meals per day, 3.69 for feeling too tired to do housework after leaving work. Conclusions: Gig economic workers are exposed to violence and job stress in the workplace more than general workers, and the proportion of workers reporting depressive symptoms is also high. These factors are associated to depressive symptoms. Furthermore, the gig workers associated between depressive symptoms and exposure to violence, job stress.

• Macromolecular Research
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• 제12권6호
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• pp.564-572
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• 2004

Modem applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal, or mechanical properties, especially when coupled with locally controlled distribution of the directional response. Such materials are difficult to engineer by conventional methods, but the electric field-aided technology presented herein is able to locally tailor electroactive composites. Applying an electric field to a polymer in its liquid state allows the orientation of chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixtures of pre-polymers and cross-linking agents. Upon curing, a 'created composite' results; it consists of these 'pseudofibers' embedded in a matrix. One can also create oriented composites from embedded spheres, flakes, or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of the field-aided self-assembled composites. The strength and duration of exposure of the electric field control the degree of anisotropy created. Results of electromechanical testing of these modified materials, which are relevant to sensing and actuation applications, are presented. The materials' micro/nanostructures were analyzed using microscopy and X-ray diffraction techniques.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3083-3087
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• 2013

Diacetylene lipid monomers possess the capability to self-assemble into vesicles via polymerization under ultraviolet irradiation, resulting in the formation of polydiacetylene (PDA) liposomes. Exposure of the polymerized vesicles to external stimuli is known to induce a unique blue-to-red color transition. The cyclic oligosaccharide ${\alpha}$-cyclodextrin known for its use in many applications, such as drug delivery, purification, and stimulus sensing, is able to form an inclusion complex with poly(ethylene glycol) (PEG) in aqueous solution. In this study, we prepared polymeric liposomes with PEG (PEG-PDA) with the aim of improving the stability of the vesicles and colorimetric response toward ${\alpha}$-cyclodextrin. We demonstrated that PEG-PDA liposome displays unique characteristics compared with native PDA liposome and it also shows apparent chromic properties of the inclusion complex formation with ${\alpha}$-cyclodextrin.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.568-570
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• 2009

Octadecyltrichlorosilane (OTS) self-assembled monolayer was selectively patterned by deep ultraviolet exposure, resulting in differential surface state, hydrophilic area with OTS hydrophobic surroundings. High-resolution (<10 ${\mu}m$) nanoparticulate Ag electrodes and organic semiconductors were patterned from simple dip-casting and ink-jetting on the pre-patterned hydrophilic surface, forming all solution-processed organic thin film transistors. The devices typically have shown a mobility of 0.065 $cm^2/V{\cdot}s$ and on-off current ratio of $8{\times}10^5$.

• 아동학회지
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• 제18권2호
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• pp.105-120
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• 1997

The purpose of this study was to investigate children's abilities of self-control and visual information processing based on their experience with video games. Participants, divided by prior exposure to video games, were 44 seven-year-old and 48 eleven-year-old boys. The impulsive tendency of children was measured through the MFFT and The delayed satisfaction test. Visual information processing ability was assessed through perceptual speed, mental rotation, and spatial visualization tasks. No differences were found between more-and less-video-game-experienced boys. Significant differences, however, were found in visual information processing abilities. More experienced boys performed better in mental rotation and spatial visualization tasks than less experienced boys.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.90.1-90.1
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• 2013

Nature utilizes various of the colorization process. Some species of birds can express their mood of tempers by changing their collagen structures on skin. For example, turkey can change their skin color by expansion of the collagen structures, which are associated with the distinct color changes. Here, we developed bioinspired virus-based colorimetric sensors which can be genetically tuned for target molecule. Using M 13 bacteriophage, we fabricated responsive self-assembled color matrices composed of quasi-ordered fiber bundle structures. These virus matrices can exhibit color change by stimuli through fiber bundle structure modulation. Upon exposure of volatile organic compounds, the resulting multi-colored matrices exhibited distinct color changes with different ratios that can be recognized by the naked eyes. Using the directed evolutionary approaches, we genetically engineered the virus matrix to incorporate binding motif for explosive detection (i.e., trinitrotoluene (TNT)). Through utilizing a common handheld device (i.e., iPhone), we could distinguish TNT molecules down to 20 ppb in a selective manner. Our novel biomimetic virus colorimetric sensor can overcome current limitation for low response selectivity.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.369-374
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• 1994

Self-assembled (SA) and Langmuir-Blodgett (LB) monolayers of arachidic acid on silver surfaces have been investigated by a reflection-absorption Fourier transform infrared spectroscopy. Arachidic acid was adsorbed on silver as carboxylate with its two oxygen atoms bound symmetrically to the surface. Although both the SA and LB monolayers consisted of fully extended trans zigzag carbon chains, a closer examination indicated that the SA monotayers should possess a more ordered crystalline structure than the LB monolayers. The infrared spectral data dictated that the extent of methyl group exposure at the air-film interface was greater in the SA monolayers than the LB monolayers, in agreement with the contact angle measurement. From a theoretical analysis, the alkyl chains in each monolayers seemed to be tilted away from the surface normal by less than $3.5^{\circ}$, but in opposite directions. Arachidic acid monolayers were concluded to have same structure as stearic acid monolayers.

• 한국직업건강간호학회지
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• 제30권3호
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• pp.132-143
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• 2021

Purpose: The study aimed to explore experiences of the posttraumatic growth (PTG) in firefighters with repeated exposure to traumatic events. Methods: Participants were 11 firefighters from two fire departments, who had experienced more than one critical trauma events. Data were collected through personal interviews from August to October 2020 and analyzed by Colaizzi's phenomenological methods. Results: The PTG experiences were derived into four categories: 'growth in self-perception', 'rediscovery of the meaning of life', 'deep interpersonal relationships', and 'discovery of the meaning of work'. Conclusion: These findings could be used as basic information for developing PTG program for firefighters such as logo-therapy, semantic therapy, and self-disclosure intervention using expressive writing and speaking.

• 디지털융복합연구
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• 제16권9호
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• pp.347-357
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• 2018

본 연구의 목적은 간호대학생의 세계시민의식, 셀프리더십과 국제보건역량과의 관계를 파악하고 국제보건역량 증진을 위한 교육프로그램 개발의 기초자료로 활용하기 위함이다. 연구대상자는 B광역시 소재 2개 대학교와 K시 소재 1개 대학교에 재학 중인 간호대학생 207명을 대상으로 설문을 실시하였다. 자료분석은 SPSS PC 18.0을 이용하여 t-test, ANOVA, Pearson's Correlation으로 분석하였다. 연구결과 종교, 국제보건역량관련 교육유무, 국제보건 관련 대중매체 접촉경험에서 통계적으로 유의한 차이가 있었다. 대상자의 국제보건역량은 셀프리더십(r=.372, p<.01), 세계시민의식(r=.364, p<.01)과 중간정도의 상관계를 보였고 세계시민의식은 셀프리더십(r=.463, p<.01)과 강한 상관관계를 나타냈다. 본 연구 결과를 토대로 간호대학생을 위한 국제보건역량 증진 프로그램 개발 시 세계시민의식과 셀프리더십을 고려하여 개발할 필요가 있으며 그 효과를 검증하는 연구가 필요하다.

• Journal of Preventive Medicine and Public Health
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• 제37권2호
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• pp.127-132
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• 2004

Objectives : Cotinine, the major metabolite of nicotine, is a useful marker of exposure to tobacco smoke and self-reporting of smoking status is thought not to be reliable. This study aimed to evaluate the agreement between the smoking self-report among adolescents and the urinary cotinine test. Methods : The study subjects were 1226 middle and high school students in Hanam city, who were selected by stratified random sampling. The self-report about smoking behavior was compared with urine cotinine value measured with PBM $AccuSign^{\circledR}fi$ Nicotine(Princeton BioMeditech Corporation, USA). The percentage agreement, kappa and 95% confidence interval(CI) were calculated. Results : The overall percentage agreement was 88.6%, and those for boys, girls, middle school, general school and vocational school students were 87.3%, 90.1%, 93.7%, 85,5%, 90.7%, and 78.4%, respectively. The overall kappa index was 0.46(95% CI=0.39-0.54)for overall, .and those for boys, girls, middle school, general school and vocational school students were 0.56(95% CI=0.48-0.65), 0.20(95% CI=0.07-0.32), 0.21(95% CI=0.09-0.34), 0.55(95% CI=0.47-0.64), 0.42(95% CI=0.33-0.52), and 0.48(95% CI=0.36-0.60), respectively. Conclusion : The percentage agreement was relatively high but the kappa values very low for girls, and middle school students. Though the prevalence bias can be influenced by these results, the self-report was not a sufficient tool for the evaluation of adolescents' smoking status, especially in girls or middle school students.