Chungbuk National University

This paper introduces a novel approach to enhance the secrecy performance of nonorthogonal multiple access (NOMA) systems by leveraging multiple unmanned aerial vehicles (UAVs) equipped with intelligent reflecting surfaces (IRSs). In this proposed system, multiple UAVs mounted with IRSs (shortened as U/Ss) are strategically deployed to assist two legitimate users in the presence of multiple colluding eavesdroppers (CEs) or noncolluding eavesdroppers (NCEs) attempting to intercept messages. The paths from the transmitter to the users are combined with those involving the U/Ss to maximize the received message power. We derive mathematical expressions for the secrecy capacities (SCs) of the proposed U/S‐NOMA systems over Nakagami‐m m channels. Additionally, asymptotic expressions for SCs in the high transmit power region are provided. Numerical results demonstrate that the SCs of U/S‐NOMA systems significantly surpass those of traditional NOMA networks lacking U/Ss. Notably, the U/S‐NOMA systems achieve their highest SCs more rapidly than traditional NOMA systems. Consequently, the integration of U/Ss proves effective in reducing transmit power and enhancing the secrecy performance of NOMA systems. Furthermore, we also delve into the impact of key parameters such as the number of reflecting elements (REs) in U/Ss, carrier frequency, U/Ss' positions, fading order, bandwidth, number of eavesdroppers, and NOMA power allocation coefficients. Valuable recommendations are presented based on a thorough investigation of these crucial parameters.

The aging properties of boron/potassium nitrate (B/KNO3) igniter were investigated using an accelerated aging test. Stabilization of the crystal structure of the oxidizer (KNO3) was attributed to degradation by aging. A well-known igniter material, B/KNO3 is used in solid propellants for aerospace applications. Because the ignition efficiency of this ignition agent decreases with prolonged storage, a variety of aging studies have been carried out to ensure its igniting reliability. Although most studies have investigated changes in the properties associated with aging, few studies have examined changes in the component materials as causes. The accelerated aging conditions used herein induced changes in the microstructure, crystal structure, and thermal properties of B/KNO3. In particular, the impact of KNO3 crystal structure change on igniter behavior was investigated.

This study aimed to elucidate the effect of different sprouting periods (5, 10, and 15 days) and sprouted garlic (SG) parts (clove, root, and sprout) on repairing skeletal muscle injury by enhancing antioxidant capacity and promoting muscle differentiation. The antioxidant and cytoprotective effects of different sprouting periods and SG part extracts were evaluated in hydrogen peroxide (H2O2)-exposed C2C12 cells. Among the three sprouting periods and three SG parts, SG harvested at 10 days showed significantly higher protective activities. SG treatment mitigated H2O2-mediated stress damage in C2C12 cells by increasing glutathione levels and decreasing the reactive oxygen species and malondialdehyde levels. SG also enhanced muscle differentiation and inhibited muscle protein degradation. In conclusion, this study suggested that 10-day SG sprouts could serve as an effective nutraceutical for improving muscle function and combating oxidative stress.

In this study, an innovative spray‐drying‐based approach for the design and synthesis of 3D hierarchical porous microspheres comprised of Si nanospheres and zeolitic imidazolate framework‐8 (ZIF‐8)‐derived hollow N‐doped carbon nanocages is presented. This sophisticated design of Si‐based carbonaceous framework is characterized by the hollow N‐doped carbon cages, which can reinforce the electrical conductivity of Si nanosphere, facilitate the electrolyte penetration into the nanostructure, and effectively alleviate the volume changes that occur during cycling. Notably, pitch‐derived carbon is coated evenly on the surface of the framework, generating a conformal coating that can effectively encapsulate the Si nanoparticles. The prepared composite microsphere is characterized by the 3D conductive network to which Si nanoparticles are evenly distributed, which play the role of a powerful mixed ion and electron conductor, highly enhancing the electrochemical properties when applied as anodes in lithium–ion batteries. The microspheres exhibit high structural robustness during 500 charge–discharge cycles when cycled at 1.0 A g⁻¹. To validate the practicability, the microspheres are blended with graphite for preparation of anode and coupled with Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) to prepare full cell, which exhibit ≈91% capacity retention after 100 cycles at 0.5 C.

To accommodate the antenna demand for rural communication and safety monitoring a shared aperture muti-port antenna sensor is presented for three different operating frequencies covering both Sub- 6 GHz and 5G millimeter-wave bands. The antenna sensor is designed on a single substrate, while different ports are connected to different radiating elements to achieve multiple frequency responses. The simulated and measured findings show that the presented antenna can cover TV-white-space (TVWS) frequency band, 5.8 GHz ISM band, and the 5G millimeter-wave frequency band. At the TVWS band, the antenna yields an omnidirectional radiation pattern with a peak gain of 3.14 dBi. While the antenna provides a unidirectional radiation pattern at the 5.8 GHz ISM and 5G millimeter-wave band with a peak gain of 6.76 dBi and 7.68 dBi, respectively. Moreover, all the antenna ports offer a radiation efficiency of more than 92%. Additionally, the 2-port MIMO configuration at the 5G millimeter-wave band shows excellent MIMO diversity performances by utilizing the proposed novel decoupling structure, which consists of metallic stub and cavity vias. Overall performance of the proposed antenna, especially the three operating frequency band including the TVWS band, makes it a viable solution for the sensing and communication in rural areas.

BACKGROUND The epigenetic mechanisms underlying early-onset acute myocardial infarction (AMI) remain insufficiently characterized. The present study aims to elucidate the pathophysiology of early-onset AMI by investigating its epigenetic features as molecular indicators. METHODS A comparative differential methylation analysis was performed on whole blood samples from 298 patients with early-onset AMI with clinical follow-up and 247 controls using targeted bisulfite sequencing. Clusters of differentially methylated sites (CDMSs) were defined to highlight regions of concentrated methylation changes in patients with early-onset AMI. Cox proportional hazards regression was conducted to evaluate the prognostic significance of the methylation biomarkers. RESULTS A total of 692 differentially methylated sites (DMSs) were identified as biomarkers associated with early-onset AMI. Among these, 396 DMSs were grouped into 147 CDMSs. Notably, the UHRF1 and STIMATE genes, which regulate synthetic and osteoblast-like vascular smooth muscle cell phenotypes, respectively, contained CDMSs with the highest number of significant DMSs. UHRF1 demonstrated a CDMS with 10 significant DMSs within a 117-bp region, while STIMATE included a 264-bp CDMS with 10 significant DMSs. Both regions also exhibited consistent methylation patterns in coronary tissues, comparing human coronary plaque to normal coronary artery samples. Additionally, the HIPK3 gene, which modulates STAT3 expression, thereby promoting osteoblast-like transformation in vascular smooth muscle cells, showed a CDMS with 5 significant DMSs within a 123-bp region, with further validation in the corresponding tissues. Furthermore, over 66% biomarkers demonstrated significant associations with mortality in patients with early-onset AMI, providing evidence of the impact of these biomarkers on the pathophysiology of the disease. CONCLUSIONS This innovative epigenomic study into early-onset AMI not only identifies biomarkers associated with the disease and its mortality but also highlights the critical role of vascular smooth muscle cell phenotype regulation in early-onset AMI pathogenesis. Our findings suggest that changes in vascular smooth muscle cell phenotypes toward synthetic and osteoblast-like states play a crucial role in early-onset AMI.

This study examines public attitudes in a democratic state toward China as a non-democratic superpower within a social psychological framework. Employing 2021 survey data from South Korea, it investigates how ideological orientations—right-wing authoritarianism (RWA) and social dominance orientation (SDO)—along with historically rooted national images of China shape attitudes toward China-related issues. The key findings are as follows: (1) Preferences for global leadership are influenced by perceptions of China as a “barbarian” or an “imperial” state, highlighting the role of soft power. (2) South Koreans who perceive China as a barbarian state are more likely to confront rather than avoid Chinese provocations, reflecting the influence of national identity on foreign policy attitudes. (3) A curvilinear relationship emerges between RWA and attitudes toward China, while SDO is consistently associated with less negative perceptions of China. These results suggest that historical narratives and orientations regarding intergroup biases, rather than ideological divides, better explain attitudes toward China.

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are representative neurodegenerative diseases with abnormal energy metabolism and altered distribution and deformation of mitochondria within neurons, particularly in brain regions such as the hippocampus and substantia nigra. Neurons have high energy demands; thus, maintaining a healthy mitochondrial population is important for their biological function. Recently, exosomes have been reported to have mitochondrial regulatory potential and antineurodegenerative properties. This review presents the mitochondrial abnormalities in brain cells associated with AD and PD and the potential of exosomes to treat these diseases. Specifically, it recapitulates research on the molecular mechanisms whereby exosomes regulate mitochondrial biogenesis, fusion/fission dynamics, mitochondrial transport, and mitophagy. Furthermore, this review discusses exosome-triggered signaling pathways that regulate nuclear factor (erythroid-derived 2)-like 2-dependent mitochondrial antioxidation and hypoxia inducible factor 1α-dependent metabolic reprogramming. In summary, this review aims to provide a profound understanding of the regulatory effect of exosomes on mitochondrial function in neurons and to propose exosome-mediated mitochondrial regulation as a promising strategy for AD and PD.

Various bioactive materials, including peptides, have become potential candidates for slowing cancer growth and metastasis. Among bioactive peptides, a synthetic cell-penetrating peptide referred to as rat sarcoma (RAS)-binding peptide (RBP) was suggested as a potential entity that targets RAS with high affinity in MDA-MB-231 cancer cells. This RAS binding further inhibits the RAS–rapidly accelerated fibrosarcoma (RAF) protein–protein interaction. The current study revealed that RBP effectively suppresses proliferation and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation by disrupting the RAS–RAF interaction. This intervention not only inhibits cell migration and invasion but also has substantial potential for preventing metastasis. The RAS–RAF–ERK1/2 pathway is a key target for anticancer drug development because of frequent ERK and mitogen-activated protein kinase activation in human cancers. MDA-MB-231, a triple-negative breast cancer cell line, harbors a G13D Kirsten rat sarcoma viral oncogene homolog mutation, making it resistant to many drugs. In addition to its in vitro antitumor activity, RBP was identified as a potent antagonist that substantially arrests tumor growth and invasiveness in in vivo chicken egg and mouse xenograft tumor models. Notably, histopathological analyses revealed increased immune cell infiltration and decreased Ki-67 expression, confirming the ability of RBP to inhibit tumor cell proliferation. Taken together, these findings highlight RBP as a therapeutic anticancer biomaterial capable of impeding the progression and metastasis of RAS-mutated cancers.

This study investigates the mechanisms and conditions through which coworker knowledge sharing influences employee creativity, grounded in the conservation of resources (COR) theory. Specifically, the study proposes that employee self‐efficacy functions as a mediating mechanism in the relationship between coworker knowledge sharing and employee creativity, while job demands serve as a boundary condition for this indirect effect. To test these hypotheses, two studies were conducted in South Korea. Study 1 analyzed data from 198 supervisor–employee dyads within a state‐owned enterprise, while Study 2 examined data from 241 dyads across six of the nation's largest private companies. Results indicate that coworker knowledge sharing significantly enhances employee creativity, with self‐efficacy fully mediating this relationship. Furthermore, the findings reveal that job demands moderate both the effect of coworker knowledge sharing on employee self‐efficacy and the indirect effect of coworker knowledge sharing on employee creativity via self‐efficacy. The study discusses implications for both theory and practice.

Glutamatergic neurons of the dorsal root ganglion (DRGg) exert a significant effect on peripheral nociceptive signal transmission. However, assessing the explicit modulatory effect of DRGg during chronic neuropathic pain (CNP) with neuromodulation techniques remains largely unexplored. Therefore, we inhibited DRGg by optogenetic stimulation and examined whether it could alleviate CNP and associated anxiety-related behaviors in a chronic compressed DRG (CCD) rat model. The CCD pain model was established by inserting an L-shaped rod into the lumbar 5 (L5) intervertebral foramen, and either AAV2-CaMKIIα-eNpHR3.0-mCherry or AAV2-CaMKIIα-mCherry was injected into the L5 DRG. Flexible optic fibers were implanted to direct yellow light into the L5 DRG. Pain and anxiety-related behavioral responses were assessed using mechanical threshold, mechanical latency, thermal latency, and open field tests. In vivo single-unit extracellular recording from the DRG and ventral posterolateral (VPL) thalamus was performed. CNP and anxiety-related behavioral responses along with increased neural firing activity of the DRG and VPL thalamus were observed in CCD animals. Enhanced expression of nociception-influencing molecules was found in the DRG and spinal dorsal horn (SDH). In contrast during optogenetic stimulation, specific DRGg inhibition markedly alleviated the CNP responses and reduced the DRG and VPL thalamic neural hyperactivity in CCD animals. Inhibition of DRGg also reduced the active expression of nociceptive signal mediators in the DRG and SDH. Taken together, our findings suggest that CaMKIIα-NpHR-mediated optogenetic inhibition of DRGg can produce antinociceptive effects in CCD rats during peripheral nerve injury-induced CNP condition by altering peripheral nociceptive signal input in the spinothalamic tract.

SARS-CoV-2 variants resistant to current antivirals remain a significant threat, particularly in high-risk patients. Although nirmatrelvir and ensitrelvir both target the viral 3CL protease (M pro ), their distinct susceptibility profiles may allow alternative therapeutic approaches. Here, we identified a novel deletion mutation at glycine 23 (Δ23G) in M pro that conferred substantial resistance to ensitrelvir (~ 35-fold) while paradoxically increasing susceptibility to nirmatrelvir (~ 8-fold). This opposite susceptibility pattern was confirmed both in vitro and in a hamster infection model. Recombinant viruses carrying M pro -Δ23G exhibited impaired replication, pathogenicity, and transmissibility compared to wild-type, though the co-occurring mutation T45I partially restored viral fitness. Structural analyses revealed critical conformational changes in the catalytic loop (Ile136–Val148) and β-hairpin loop (Cys22–Thr26), directly influencing inhibitor binding selectivity. These results highlight differential resistance profiles of M pro inhibitors, supporting potential sequential or alternative use of nirmatrelvir and ensitrelvir in patients requiring prolonged antiviral treatment.

This study investigated the effects of supplemental far-red (FR) lighting on photomorphogenic responses and productivity in Crepidiastrum denticulatum, a native Korean medicinal plant, grown in vertical farms using artificial lighting. Photomorphogenesis refers to the growth and developmental changes in plants in response to light signals. The background light sources were white (W) light-emitting diodes (LEDs) and red, green, and blue (RGB) mixed LEDs. Supplemental FR lighting was added to both background light sources at a red to far-red (R/FR) ratio of 1.2, referred to as W + FR and RGB + FR treatments. Fluorescent light (FL) served as a control. Plants were cultivated under five light treatments for six weeks in a controlled environment with an air temperature 20°C, relative humidity 60%, photosynthetic photon flux density 200 µmol·m–2·s–1, photoperiod 16 h·d–1, and CO2 concentration 1000 µmol·mol–1. The addition of supplemental FR lighting significantly influenced photomorphogenic response, enhancing plant growth by increasing leaf area and biomass by up to 2.7 times compared to the control. Canopy net photosynthetic rates were significantly increased by supplemental FR lighting, especially under the W + FR treatment. While total phenolic content and antioxidant capacity per unit dry weight were highest under the RGB treatment, the W + FR treatment exhibited the highest accumulation of these metabolites per shoot due to increased biomass. These findings suggested that supplemental FR light effectively modulates photomorphogenic responses, enhancing growth and bioactive compound accumulation in C. denticulatum. The results indicate the potential of manipulating light quality, particularly by adding FR light, to optimize vertical farming practices for medicinal plants.

In this chapter, we critically analyze the existing models of critical literacy dominantly constructed by western scholars, review two authors’ empirical research and suggest ways to localize the existing models of critical literacy in Korean EFL contexts. The motivation is from the need to have a specific critical literacy model in an EFL context. Two authors’ empirical research identifies the need to link conventional and critical literacies guided by bringing in intercultural citizenship education framework and strengthening the connections between affective domains and critical literacies. Broadening the concepts of social actions is also suggested for innovative pedagogical implementation of critical literacies. We argue that localized adaptions of critical literacy require linguistical, affective, and cognitive dimensions in teaching of critical literacy. An innovative critical literacy model in EFL contexts should have a conventional literacy instruction component but also should connect personal engagement and social action with a critical stance. These innovative suggestions encompass critical thinking, affective connection with others’ emotions, awareness of potential socio-political actions on top of traditional language development. We claim that these suggestions can be localized and contextualized in different educational situations in EFL contexts by interrogating local needs, literacy curriculum, materials available and innovating teachers’ pedagogical approaches.

A 7‐year‐old neutered female Shih Tzu presented with bilateral skin lesions and a subcutaneous mass in the submandibular region. The initial lesion on the right appeared as a plaque, followed by the development of an ulcer on the opposite side 2–3 days later. Despite treatment with antibiotics, antifungal drugs and anti‐inflammatory steroids, lesions persisted. There was an initial improvement with steroids; however, the lesions developed into scars, erythema and papules. A biopsy revealed eosinophilic and mixed‐cell dermatitis requiring treatment with immunosuppressive steroids and cyclosporine, which resolved the plaque and ulcer but only partially reduced the subcutaneous mass. Surgical resection was considered, and subsequent skull radiography revealed alveolar bone loss. During surgery, a sinus tract was identified extending from teeth 309 to 409, indicating that the tissue changes were likely due to drainage from the periodontal disease. Based on clinical history and examination results, the case was definitively diagnosed as an odontogenic cutaneous sinus tract (OCST). Following surgery, no recurrence of the lesion or mass was observed. This is the first case report describing the histopathological features of a submandibular OCST in a dog, highlighting the importance of considering this condition when submandibular lesions do not fully respond to immunosuppressive therapy.

The narrow‐ridged finless porpoise (Neophocaena asiaeorientalis Pilleri & Gihr, 1972) is one of the most endangered cetacean species inhabiting East Asian waters. Complete mitogenome analysis offers accurate phylogenetic insights; however, complete mitogenome sequences for the narrow‐ridged finless porpoise have so far been restricted to specific regions, mainly in China, and no sequences are available from Korean or Japanese populations. To address this gap, in this study, we developed a multiplex PCR primer panel to sequence the complete mitochondrial genome of the porpoise and sequenced 23 individuals of N. a. sunameri, a subspecies of N. asiaeorientalis, from Korean waters using next‐generation sequencing. Phylogenetic analyses based on maximum likelihood and Bayesian inference revealed three major, well‐supported monophyletic clades within the species. Two sequences of the Yangtze finless porpoise (N. a. asiaeorientalis), another subspecies, displayed significantly higher genetic divergence compared to N. a. sunameri sequences. The 23 mitochondrial genome sequences exhibited a nucleotide diversity of 0.142% and a haplotype diversity of 99.6%, with 22 unique haplotypes identified. These findings contribute to our understanding of the evolutionary history and genetic diversity of the species, providing valuable insights for future conservation efforts and further genetic research. image

Ginseng (Panax species), are significant medicinal plants, have been utilized worldwide for their nutritional and therapeutic properties throughout history. While traditional cultivated ginseng is typically harvested after 6 years, and harvesting earlier than 6 years possess lower levels of ginsenosides. Recent technological advances have increased the use of in vitro techniques for production of ginseng biomass and ginsenosides via cell and/or adventitious root culture. Here, the metabolic profiles of a range of ginseng samples systems of cultivation ages, cultivars, and culture systems of in vitro-cultured and field cultivated ginseng were examined to determine whether Fourier-transform infrared (FT-IR) spectra combined with multivariate analysis of whole-cell ginseng extracts could be used for high-throughput sample discrimination. In total, 26 ginseng samples belonging to four categories were analyzed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). Dendrograms based on hierarchical cluster analysis (HCA) of the ginseng sample spectral patterns showed that cultivation ages and culture systems were readily clustered into two subgroups in a polysaccharide spectrum-dependent manner. The sample group containing in vitro cell and organ samples was segregated into four subgroups in a nucleic acid spectrum-dependent manner. These results indicated that FT-IR spectroscopy combined with multivariate statistical analysis of in vitro and ex vitro ginseng could be used as an alternative method for metabolite discrimination. Consequently, PLD-DA analysis of FT-IR metabolic fingerprinting data could serve as a valuable tool for screening bioactive compounds and exploring metagenomic relationships in ginseng research.

In the pursuit of enhancing the environmental sustainability of concrete, a fundamental construction material, traditional approaches often emphasize minimizing maintenance requirements to extend lifespan and improve durability. Departing from these conventional strategies, an innovative method aimed at augmenting thermal insulation and eco‐friendliness of building structures is proposed, which involves the integration of nanoclay (NC) hydrogel to confer multifunctionality upon cement materials. Within the hydrogel matrix, NC functions as an internal cross‐linking agent, establishing robust bonds with cement through a surface pozzolanic reaction. Rigorous validation of this interaction is conducted through meticulous adhesion measurements, assessments of changes in bonding energy, and simulations of shear forces. Significantly, the bonded NC hydrogel, enriched with water, demonstrates a remarkable ability to supply essential moisture for the successful settlement and growth of aquatic organisms and moss. This comprehensive study underscores the potential of NC hydrogel as an invaluable material for establishing the foundations of thriving ecosystems, presenting a promising avenue for sustainable construction practices.

The rapid growth of technologies and miniaturization of electronic devices demand advanced the use of high-powered energy storage devices. The energy storage device are utilized in modern wearable electronics, stretchable screens, and electric vehicles. Due to their favorable electrochemical properties, nanomaterials have been used as electrodes for supercapacitors (SCs) with high power density, but they generally suffer from lower energy density than batteries. Compared to various nanomaterials, MXenes and transition metal chalcogenides (TMCs) have shown great potential for energy storage applications such as SCs. TMCs are gaining attention due to their stable electrochemical nature, adjustable surface activity, high electric conductivity, abundant chemically active sites, and stable cycling performance. However, the interlayer restacking and agglomeration of 2D materials limit their cycling performance. To overcome this, TMCs@MXene heterostructures have been developed, offering structurally stable electrodes with enhanced chemical active sites. In this review, we discuss recent advances in the development of different TMCs@MXene-based hybrids for the design of high performance SCs with improved specific capacitance, cycling life, energy density, and power density. The recent developments of this research field focusing on MXene-transition metal sulfides, MXene-transition metal selenides, and MXene-transition metal tellurides are elaborately discussed. Theoretical calculations carried out to understand the charge-storage mechanisms in these composites are reviewed. The importance of bimetallic TMCs and MXene heterostructure for enhanced energy storage is also highlighted.