Distinct patterns of Internet and smartphone-related problems among adolescents by gender: Latent class analysis

Lee, Seung-Yup,Lee, Donghwan,Nam, Cho Rong,Kim, Da Yea,Park, Sera,Kwon, Jun-Gun,Kweon, Yong-Sil,Lee, Youngjo,Kim, Dai Jin,Choi, Jung-Seok AKADEMIRI KIRDO 2018 JOURNAL OF BEHAVIOURAL ADDICTIONS Vol.7 No.2

<P><B>Background and objectives</B></P><P>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).</P><P><B>Methods</B></P><P>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 χ<SUP>2</SUP> tests, post-hoc tests were conducted to examine differences among the LCA subgroups.</P><P><B>Results</B></P><P>In the whole group (<I>n</I> = 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.</P><P><B>Conclusions</B></P><P>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.</P>

외과가 당면한 비보험 급여화의 문제점

Sera Lee 대한외과학회 2017 대한외과학회 학술대회 초록집 Vol.2017 No.11

Health Effects of Short-term Exposure to Particulate Matter in People with Disabilities

Sera Kim(Sera Kim),Jong-Tae Lee(Jong-Tae Lee) 한국환경보건학회 2021 한국환경보건학회 학술대회 자료집 Vol.2021 No.2

Capillary Force-Induced Glue-Free Printing of Ag Nanoparticle Arrays for Highly Sensitive SERS Substrates

Lee, Jaehong,Seo, Jungmok,Kim, Dayeong,Shin, Sera,Lee, Sanggeun,Mahata, Chandreswar,Lee, Hyo-Sung,Min, Byung-Wook,Lee, Taeyoon American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.12

<P>The fabrication of well-ordered metal nanoparticle structures onto a desired substrate can be effectively applied to several applications. In this work, well-ordered Ag nanoparticle line arrays were printed on the desired substrate without the use of glue materials. The success of the method relies on the assembly of Ag nanoparticles on the anisotropic buckling templates and a special transfer process where a small amount of water rather than glue materials is employed. The anisotropic buckling templates can be made to have various wavelengths by changing the degree of prestrain in the fabrication step. Ag nanoparticles assembled in the trough of the templates via dip coating were successfully transferred to a flat substrate which has hydrophilic surface due to capillary forces of water. The widths of the fabricated Ag nanoparticle line arrays were modulated according to the wavelengths of the templates. As a potential application, the Ag nanoparticle line arrays were used as SERS substrates for various probing molecules, and an excellent surface-enhanced Raman spectroscopy (SERS) performance was achieved with a detection limit of 10<SUP>–12</SUP> M for Rhodamine 6G.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-12/am5000382/production/images/medium/am-2014-000382_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5000382'>ACS Electronic Supporting Info</A></P>

Highly Sensitive Multifilament Fiber Strain Sensors with Ultrabroad Sensing Range for Textile Electronics

Lee, Jaehong,Shin, Sera,Lee, Sanggeun,Song, Jaekang,Kang, Subin,Han, Heetak,Kim, SeulGee,Kim, Seunghoe,Seo, Jungmok,Kim, DaeEun,Lee, Taeyoon American Chemical Society 2018 ACS NANO Vol.12 No.5

<P>Highly stretchable fiber strain sensors are one of the most important components for various applications in wearable electronics, electronic textiles, and biomedical electronics. Herein, we present a facile approach for fabricating highly stretchable and sensitive fiber strain sensors by embedding Ag nanoparticles into a stretchable fiber with a multifilament structure. The multifilament structure and Ag-rich shells of the fiber strain sensor enable the sensor to simultaneously achieve both a high sensitivity and largely wide sensing range despite its simple fabrication process and components. The fiber strain sensor simultaneously exhibits ultrahigh gauge factors (∼9.3 × 10<SUP>5</SUP> and ∼659 in the first stretching and subsequent stretching, respectively), a very broad strain-sensing range (450 and 200% for the first and subsequent stretching, respectively), and high durability for more than 10 000 stretching cycles. The fiber strain sensors can also be readily integrated into a glove to control a hand robot and effectively applied to monitor the large volume expansion of a balloon and a pig bladder for an artificial bladder system, thereby demonstrating the potential of the fiber strain sensors as candidates for electronic textiles, wearable electronics, and biomedical engineering.</P> [FIG OMISSION]</BR>

Highly Stable Surface-Enhanced Raman Spectroscopy Substrates Using Few-Layer Graphene on Silver Nanoparticles

Lee, Jaehong,Shin, Sera,Kang, Subin,Lee, Sanggeun,Seo, Jungmok,Lee, Taeyoon Hindawi Limited 2015 Journal of nanomaterials Vol.2015 No.-

<P>Graphene can be effectively applied as an ultrathin barrier for fluids, gases, and atoms based on its excellent impermeability. In this work, few-layer graphene was encapsulated on silver (Ag) nanoparticles for the fabrication of highly stable surface-enhanced Raman scattering (SERS) substrates, which has strong resistance to oxidation of the Ag nanoparticles. The few-layer graphene can be successfully grown on the surface of the Ag nanoparticles through a simple heating process. To prevent the agglomeration of the Ag nanoparticles in the fabrication process, poly(methyl methacrylate) (PMMA) layers were used as a solid carbon source instead of methane (CH4) gas generally used as a carbon source for the synthesis of graphene. X-ray diffraction (XRD) spectra of the few-layer graphene-encapsulated Ag nanoparticles indicate that the few-layer graphene can protect the Ag nanoparticles from surface oxidation after intensive annealing processes in ambient conditions, giving the highly stable SERS substrates. The Raman spectra of Rhodamine 6G (R6G) deposited on the stable SERS substrates exhibit maintenance of the Raman signal intensity despite the annealing process in air. The facile approach to fabricate the few-layer graphene-encapsulated Ag nanoparticles can be effectively useful for various applications in chemical and biological sensors by providing the highly stable SERS substrates.</P>

Synergistic effects of 2A-mediated polyproteins on the production of lignocellulose degradation enzymes in tobacco plants

Lee, Dae-Seok,Lee, Kwang-Ho,Jung, Sera,Jo, Eun-Jin,Han, Kyung-Hwan,Bae, Hyeun-Jong Oxford University Press 2012 Journal of experimental botany Vol.63 No.13

<P>Cost-effective bioethanol production requires a supply of various low-cost enzymes that can hydrolyse lignocellulosic materials consisting of multiple polymers. Because plant-based enzyme expression systems offer low-cost and large-scale production, this study simultaneously expressed β-glucosidase (<I>BglB</I>), xylanase (<I>XylII</I>), exoglucanase (<I>E3</I>), and endoglucanase (<I>Cel5A</I>) in tobacco plants, which were individually fused with chloroplast-targeting transit peptides and linked via the 2A self-cleaving oligopeptideex from foot-and-mouth disease virus (FMDV) as follows: [RsBglB-2A-RaCel5A], [RsXylII-2A-RaCel5A], and [RsE3-2A-RaCel5A]. The enzymes were targeted to chloroplasts in tobacco cells and their activities were confirmed. Similarly to the results of a transient assay using <I>Arabidopsis thaliana</I> protoplasts, when <I>XylII</I> was placed upstream of the 2A sequence, the [RsXylII-2A-RaCel5A] transgenic tobacco plant had a more positive influence on expression of the protein placed downstream. The [RsBglB-2A-RaCel5A] and [RsE3-2A-RaCel5A] transgenic lines displayed higher activities towards carboxylmethylcellulose (CMC) compared to those in the [RsXylII-2A-RaCel5A] transgenic line. This higher activity was attributable to the synergistic effects of the different cellulases used. The [RsBglB-2A-RaCel5A] lines exhibited greater efficiency (35–74% increase) of CMC hydrolysis when the exoglucanase CBHII was added. Among the various exoglucanases, E3 showed higher activity with the crude extract of the [RsBglB-2A-RaCel5A] transgenic line. Transgenic expression of 2A-mediated multiple enzymes induced synergistic effects and led to more efficient hydrolysis of lignocellulosic materials for bioethanol production.</P>

Cost Stickiness of Private and Public Firms: Some Mediation Analyses

( Sera Choi ),( Iny Hwang ),( Moony Lee ),( Woo-jong Lee ) 한국회계학회 2021 회계학연구 Vol.46 No.2

This paper extends prior literature on cost behavior by providing evidence of whether and how access to public financing affects the degree of SG&A cost stickiness. Based on a comprehensive dataset covering both public and private firms in Korea, we document that the degree of cost stickiness is, in general, greater for private firms than it is for public firms. Furthermore, we identify four candidate mediators for the association between listing status and cost stickiness: demand uncertainty, financial risk, reporting incentives, and ownership wedge. Mediation analyses reveal that demand uncertainty mainly accounts for the difference in cost stickiness between private and public firms. This finding suggests that public firms better address uncertainty by diversifying idiosyncratic risk in the capital market than private firms do and hence exhibit lower asymmetry in SG&A costs. Overall, we present evidence that access to equity financing influences operations and consequently affects cost behavior.

Analysis of Concomitant Medications and Comorbidities in Patients Received PN and Experienced ADRs

( Sera Lee ),( Miyoung Ock ),( Edward Kim ),( Su Hyun Kim ),( Hyunah Kim ) 한국정맥경장영양학회 2017 한국정맥경장영양학회 학술대회집 Vol.2017 No.-

Purpose: To evaluate frequently used medications and comorbidities among patients who experienced adverse drug reactions (ADR) while receiving parenteral nutrition (PN). Methods: Korean Adverse Event Reporting System (KAERS) database from 2015 was used for analysis. Adult patients (≥19 years old) who received PN and experienced ADRs were included. The following five specific agents in PN were identified to be causative agents: amino acids, fat emulsions, carbohydrates, combinations and solutions for PN. These agents were classified as “certain,” “probable,” or “possible” to cause ADRs in corresponding patients based on the WHO-Uppsala Monitoring Centre criteria. Results: We evaluated total of 1,529 ADRs from 1,036 patients. Mean patient age was 57 (±15.6) and mean number of ADRs per patient was 1.5 (±0.7). Frequently reported concomitant agents were opioids (60 cases, 13.0%), other betalactam antibacterials (45 cases, 9.8%), drugs for peptic ulcer and GERD (42 cases, 9.1%), non-steroid antiinflammatory and antirheumatic products (33 cases, 7.2%) followed by propulsives (12 cases, 2.6%), other analgesics and antipyretics (12 cases, 2.6%), and other antibacterials (12 cases, 2.6%). The leading frequent comorbidities were malignancy (416 cases, 33.0%), diseases of the digestive systems (96 cases, 7.6%), diseases of circulatory system (80 cases, 5.3%), injury, poisoning and certain other consequences of external causes (77 cases, 6.1%), diseases of musculoskeletal system and connective tissue (73 cases, 5.8%), and endocrine, nutritional and metabolic diseases (72 cases, 5.7%). Conclusion: Our study showed that opioid was the most frequently used concurrent medication in patients who experienced ADRs while on PN. The most frequent comorbidity was malignancy. Patients who will be receiving PN with these concurrent medications or comorbidities may need more stringent monitoring for ADRs.

The Usefulness of Other Comprehensive Income for Predicting Future Earnings

LEE, Joonil,LEE, Su Jeong,CHOI, Sera,KIM, Seunghwan Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.5

This study investigates whether other comprehensive income (OCI) reported in the statement of comprehensive income (one of the main financial statements after the adoption of K-IFRS) predicts a firm's future performance. Using the quarterly data of Korean listed companies, we examine the association between OCI estimates and future earnings. First of all, we find that OCI is positively associated with earnings in both 1- and 2-quarter ahead, supporting the predictive value of OCI. When we break down OCI into its individual components, our results suggest that the net unrealized gains/losses on available-for-sale (AFS) investment securities are positively associated with future earnings, while the other components (e.g., net unrealized gains/losses on valuation of cash flow hedge derivatives) present insignificant results. In addition, we investigate whether the reliability in OCI estimates enhances the predictive value of OCI to predict future performance. We find that the predictive ability of OCI, in particular the net unrealized gains/losses on available-for-sale (AFS) investment securities, becomes more pronounced when firms are audited by the Big 4 audit firms. Overall, our study suggests that information content embedded in OCI can provide decision-useful information that is helpful for the prediction of future firm performance.