Soonchunhyang University

Martin G.L., Lee S., Kim J., Jeong Y., Kang A.R., Woo J.

The prevalence of non-executable malware is on the rise, presenting a major threat to users, including major public institutions and corporations. While extensive research has been conducted on detecting malware threats, there is a noticeable gap in studying document-type malware compared with executable files. The proposed model will solve this gap by detecting and classifying document-type malware families using script codes, including tags, to write documents and script languages to execute malicious functions. These script codes offer insights into how the malware was constructed and operates on the victim’s system. Additionally, we leverage language models in our approach. Initially, we develop MalCode2Vec to learn associations between source codes and represent them as numeric vectors. Subsequently, we design a Transformer-based model for document malware detection and family classification. Detection is conducted at both the stream and file levels. To solve the class imbalance issue in the malware family, we utilize a generative adversarial network to generate malware samples. Our experimental domain focuses on the Hangul (Korean) word processor, a tool notably used by North Korea in targeting the South Korean government.

Chi S., Ko J., Kang J., Gim J., Lee M.

Kang M., Kim J.

Jeong S., Min S.D.

Lee Y.J., Lee J.Y., Cho J.H., Kang Y.J., Choi J.H.

Kim J., Jo T., Nam H., Kim B.J., Nam S.M., Kim J., Choi J., Jeong W.

The aim of this study was to investigate the impact of exosomes derived from adipose-derived stem cells (ASCs) on complications arising from hyaluronic acid (HA) filler injections.

Jin H., Eom Y.

The escalation of fungal infections is driving an increase in disease and mortality rates. In particular, the emergence of Candida auris (C. auris), which shows powerful resistance to the antifungal drug fluconazole, is becoming a global concern. Furthermore, several biological hurdles need to be overcome by candidate therapeutics because C. auris has the ability to form biofilm. Therefore, this study aimed to investigate the antifungal and anti-biofilm effects of plumbagin, a natural extract, against fluconazole-resistant C. auris (FRCA). The minimum inhibitory concentrations (MICs) of fluconazole and plumbagin were determined against clinically isolated C. auris. Inhibition of biofilm formation and eradication effects of plumbagin against FRCA were confirmed through minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) assays. Additionally, the inhibition of metabolic activity in biofilm cells was verified through quantification by XTT reduction assay and visualization by confocal laser scanning microscopy (CLSM). The relative expression levels of the azole resistant gene ERG11, the efflux pump gene CDR1, and the extracellular matrix gene KRE6, were measured. Plumbagin exhibits antifungal efficacy against C. auris and has been shown to effectively inhibit both the formation and eradication of biofilms produced by FRCA. Furthermore, the metabolic activity inhibition in biofilm cells was both quantified and visually observed. The downregulation of all genes (ERG11, CDR1, and KRE6) by plumbagin was confirmed. Taken together, this study demonstrates that plumbagin has antifungal and anti-biofilm efficacy against FRCA, indicating its potential as an alternative to antifungal agents and a valuable resource in combating FRCA infections.

Nam Y., Lee H.

Liang J., Ma C., Kim K.

ABSTRACTAlthough islands in South Korea have been significantly impacted by human activities, marine ecological studies focusing on island coasts have been limited. Due to their distinct characteristics, macrobenthos is extensively utilized to assess the impact of anthropogenic influences on the marine environment. In August 2010, August 2011, and September 2012, samples of macrobenthic communities, bottom water, and sediment were collected from the subtidal zones around southern Jindo and northern Jeju islands in South Korea. Macrobenthos was identified to the species level using a stereomicroscope. Bottom seawater quality was evaluated, with a focus on dissolved heavy metal concentrations (As, Cr, Cd, Cu, Pb, and Zn). Additionally, we measured the organic matter content and mean grain size of the sediment. There were marked differences in macrobenthic community structures between the two islands, including the number of species, species abundance, species richness index, and Pielou's evenness index (p < 0.05). Cluster analysis, non‐metric analysis, permutational multivariate analysis of variance (PERMANOVA), and permutational analysis of multivariate dispersion (PERMDISP) revealed variations in macrobenthic communities between the two islands and over the years 2010, 2011, and 2012. According to the Biota‐Environment Matching (BIO‐ENV), distance‐based redundancy analysis (dbRDA), and distance‐based linear model analyses (DistLM), the principal environmental variables influencing the distribution of macrobenthic communities are Cd and As. These variations likely result from different levels of human activity on each island. Moreover, interannual variations in macrobenthic communities, especially in 2012, were predominantly influenced by Pb and Cr, likely due to alterations in the influence of the Changjiang (Yangtze River) diluted water.

Kim W., Lee Y., Jung S., Lee S.

Kim H., Kim J., Shin Y.E., Yoo H., Yoo J., Kim S.G., Kim Y.

Besifovir dipivoxil maleate (BSV) is a novel antiviral agent widely used in South Korea for treating chronic hepatitis B (CHB). This study aimed to compare the incidence of hepatocellular carcinoma (HCC) following long-term use of BSV versus tenofovir alafenamide fumarate (TAF), utilizing large-scale national data. A total of 41,949 patients were analyzed, with propensity score matching (PSM) yielding 2,239 BSV and 6,717 TAF patients. The HCC incidence rate per 1,000 person-years was 1.8 for BSV versus 2.4 for TAF before matching (P = 0.057) and 1.6 versus 2.2 after matching (P = 0.284). Multivariate Cox regression identified age, male sex, antiviral duration, Charlson Comorbidity Index (CCI) score, and decompensated cirrhosis as significant risk factors for HCC, while antiviral type was not (HR 1.12, P = 0.413). Subgroup analyses showed no significant differences in HCC incidence between BSV and TAF in cirrhotic or non-cirrhotic patients. These findings suggest that BSV offers comparable efficacy to TAF in preventing HCC and is a promising option for CHB management. Longer-term studies with larger cohorts are necessary to confirm these results and assess the full impact of BSV on HCC prevention.

Lee Y., Lee S., Kim S.K., Yon D.K., Nam Y., Lee J.

Liang J., Ma C., Kim K.

Background: Jeju Island is a world-renowned tourist destination. However, with the increasing intensity of anthropogenic activities, the coastal marine environment of Jeju Island has been negatively affected. Methods and Results: Our study used five benthic indices to assess the ecological quality of the subtidal zone in northern Jeju Island. Our analysis indicated that apart from the benthic polychaetes amphipods index (BPA), other benthic indices assessed the ecological quality of the subtidal zone in northern Jeju Island as high or good. Distance-based redundancy analysis (dbRDA) indicated that pH and salinity primarily influenced macrobenthic communities in 2011 and 2012. According to the Spearman rank correlation analysis, the multivariate AZTI marine biotic Index (M-AMBI) showed stronger correlations with environmental data than other benthic indices. Conclusions: Overall, the averages of the five benthic indices suggested that the benthic ecological quality of the subtidal zone in the northern part of Jeju Island was high or good. Although immediate marine environmental management is not required, long-term monitoring remains essential. M-AMBI outperformed other benthic indices; however, we recommend using multiple benthic indices to assess the benthic ecological quality of Jeju Island due to the complexity of marine ecosystems. Effective support has been provided by our study for the marine environmental conservation along the coast of Jeju Island.

Kim W., Kang H., Lee S.

Melanin overproduction causes various skin diseases, such as spots, freckles, and wrinkles, resulting in the requirement of melanin synthesis inhibitors like 1-phenyl-2-thiourea (PTU) and kojic acid, which have been commonly used in the pharmaceutical industry. However, these inhibitors can cause side effects such as skin irritation and allergies. Therefore, it is necessary to develop safe and effective melanin inhibitors from natural resources. The purpose of this study was to investigate a whitening agent from natural substances using B16F10 melanoma cells and zebrafish model. We investigated the melanogenesis-inhibiting activities of the fractions from Sargassum pallidum extract. The ethyl acetate fraction from S. pallidum extract (SPEF) significantly decreased tyrosinase activity. SPEF also significantly reduced α-melanocyte stimulating hormone (MSH)-induced intracellular tyrosinase activity and melanin content in B16F10 cells. Moreover, SPEF inhibited the expression levels of key melanogenic proteins such as tyrosinase, TRP-1, TRP-2, and MITF by downregulating the phosphorylation levels of CREB and PKA in α-MSH-stimulated melanoma cells. Furthermore, SPEF significantly suppressed melanin synthesis in the zebrafish model with no developmental toxicity. LC-Q-TOF-MS/MS analysis identified that SPEF was composed of 12 phytochemical compounds, including diterpenes, which were the dominant metabolites. These results altogether show that SPEF effectively suppresses melanogenesis in B16F10 melanoma cells and in a zebrafish model, with potential for usage in pharmaceuticals and cosmeceuticals.

He H., Lee J., Zong Z., Liu N., Noh Y., Lynch V.M., Oh J., Kim J., Sessler J.L., Ke X.

Nanographenes, finite models of graphene sheets, are endowed with intriguing optical, electronic, and spintronic features. So-called heteroatom-doping, where one or more carbon is replaced by non-carbon light atoms has been proved effective in tuning the properties of nanographenes. Here we extend the concept of heteroatom nanographene doping to include metal centers. The method employed involves the use of a dipyrromethene fragment as an auxiliary ligand that is directly linked to the bay area of the model nanographene hexa-peri-hexabenzocoronene (HBC) to give a dipyrromethene-fused nanographene-type hybrid ligand (HBCP). HBCP has a corrole-like trianionic core that is capable of coordinating group 11 metal cations, including trivalent Cu, Ag and Au. These cations are introduced into the cavity with atomic precision to give metal complexes (HBCP-M; M = Cu, Ag, Au). The electronic structure and photophysical properties of HBCP and its metal complexes are investigated by steady-state and fs-transient spectroscopies, as well as DFT calculations. The ligand and metal complexes are also characterized via single crystal X-ray diffraction analyses. This work paves the way towards the precise metal doping of nanographenes within the carbon network, as opposed to the synthetic appendage of an independent chelating group, such as a fused tetrapyrrolic moiety. Nanographenes, finite models of graphene sheets, are endowed with intriguing optical, electronic, and spintronic features which can be tuned by replacing carbon via heteroatom-doping. Here the authors extend the concept of heteroatom nanographene doping to include metal centers.