Search Results (807)

Background/Objectives: This study explored the lived experiences of nursing students in South Korea who participated in clinical practice at Community Treatment Centers (CTCs) during the COVID-19 pandemic. Methods: This study was designed as a qualitative study and applied Colaizzi’s descriptive phenomenology. Semi-structured interviews were conducted with ten nursing students who practiced at CTCs for three to four weeks. Data were analyzed through Colaizzi’s seven procedural steps to derive the essential structure of their experience. Data saturation was achieved, and methodological rigor criteria were applied. Results: Four overarching themes emerged: (1) transformative growth through immersive clinical practice in quarantine; (2) enduring and adapting to uncertainty and emotional turmoil; (3) reconciling vulnerability and responsibility as future professionals; and (4) validation and pride in becoming visible during a national crisis. Conclusions: The study revealed that CTC practice constituted a transformative learning experience that enhanced students’ professional identity and resilience in disaster situations. Findings highlight the need to integrate disaster ethics and psychosocial preparedness into undergraduate nursing curricula. Full article

This paper analyzes a finite-capacity Markovian queueing system with two customer types, each assigned to a separate buffer, and a single alternating server whose service priority is dynamically controlled by a queue-length-based threshold policy. The arrivals of both customer types follow independent Poisson processes, and the service times are generally distributed. The server alternates between the two buffers, granting service priority to buffer 1 when its queue length exceeds a specified threshold immediately after service completion; otherwise, buffer 2 receives priority. Once buffer 1 gains priority, it retains it until it becomes empty, with all priority transitions occurring non-preemptively. We develop an embedded Markov chain model to derive the joint queue length distribution at departure epochs and employ supplementary variable techniques to analyze the system performance at arbitrary times. This study provides explicit expressions for key performance measures, including blocking probabilities and average queue lengths, and demonstrates the effectiveness of threshold-based control in balancing service quality between customer classes. Numerical examples illustrate the impact of buffer capacities and threshold settings on system performance and offer practical insights into the design of adaptive scheduling policies in telecommunications, cloud computing, and healthcare systems. Full article

Background: The human skull has a very complex and diverse structure, and morphological characteristics vary by population. The purpose of this study is to comprehensively analyze the cranial morphology using postmortem computed tomography (PMCT), and to identify anatomical characteristics through a multifaceted approach in Koreans. Methods: 358 PMCT cross-sectional images (179 males, 179 females) provided by the National Forensic Service were analyzed, and the average age was 55.1 ± 18.9 years. The maximum cranial length was divided by the maximum cranial width and multiplied by 100 to calculate the cranial index (CI). Petrous ridge–midline angle (PMA) was measured as the angle between the petrous ridge and the midline. Results: In both the classification of skull shape using CI and PMA, the brachycranic type showed the highest frequency (p < 0.001). Classified by CI, there were no significant differences in frequency by sex (p = 0.533), or age (p = 0.110). However, classified by PMA, the frequency of the brachycranic type in men was significantly higher than in women (p = 0.022), and there was a significant difference in the frequency of cranial morphology by age (p < 0.001). Conclusions: The results of cranial morphology classification targeting Koreans are expected to provide useful basic data for clinical and forensic use. Full article

Background/Objectives: Honokiol (HK), a bioactive phenolic compound, exhibits significant anti-cancer properties. This study aimed to investigate the anti-cancer effects of HK in colorectal cancer (CRC) cells by focusing on its direct interaction with heat shock protein 27 (Hsp27) as a molecular target, and to elucidate the underlying mechanisms involved. Methods: HK was isolated via silica/ODS chromatography. Anchorage-independent growth of CRC cells was quantified using a soft agar assay with increasing HK concentrations. Apoptosis and cell cycle were analyzed by flow cytometry, and cell viability by MTS assay. Hsp27 binding to HK was validated by pull-down assay with HK-conjugated Sepharose 4B beads. Hsp27 knockdown was performed using lentiviral shRNA in CRC cells. Molecular docking of HK-Hsp27 interaction employed Schrödinger Suite 2016. Protein expressions, including chaperone and apoptotic proteins, were evaluated by Western blotting. Results: HK dose-dependently suppressed anchorage-independent growth of CRC cells and induced G₀/G₁ arrest. It triggered apoptosis through cytochrome c release, PARP cleavage, and Bcl-2 downregulation. HK directly bound to the α-crystallin domain of Hsp27 at Asn102 and His103 residues, confirmed by computational molecular docking and site-directed mutagenesis. Hsp27 knockdown in CRC cells dramatically reduced anchorage-independent growth. HK markedly decreased Hsp27 protein levels while having less effect on other heat shock proteins in CRC cells. Conclusions: HK exerts anti-cancer effects in CRC cells, associated with Hsp27 inhibition, resulting in suppressed cell growth and increased apoptosis. This interaction between HK and Hsp27 may support a mechanistic foundation supporting the potential utility of HK as a natural therapeutic agent for CRC. Full article

Soil toxicity resulting from either natural or anthropogenic heavy metal contamination was evaluated through a nitrifying bacteria bioassay focused on the inhibition of oxygen consumption. Every contaminated soil sample inhibited the nitrifying bacteria bioassay, with inhibition levels ranging from 71% to 100%. The optimal conditions for maximizing O₂ consumption during the test procedure were established as follows: a test culture volume of 1 mL, a soil sample weight of 1 g, a rotation rate of 100 revolutions per minute, and a reaction duration of 48 h. In low- or uncontaminated soils, oxygen consumption ranged from 3.2 mL to 3.0 mL from a headspace volume of 1 mL filled with O₂. In contrast, contaminated soils exhibited a lower range, with values between 0.1 mL and 1.0 mL. EC50 levels for NB O₂ consumption were: Cr⁶⁺ 1.21 mg/kg; Cu²⁺ 6.92 mg/kg; Ag⁺ 8.38 mg/kg; As³⁺ 8.99 mg/kg; Ni²⁺ 10.35 mg/kg; Hg²⁺ 11.01 mg/kg; Cd²⁺ 31.33 mg/kg; Pb²⁺ 129.62 mg/kg. Values for inherent test variability (CVi), variation resulting from the natural characteristics of soil (CVns), and minimal detectable difference (MDD) were found to range between 1.6% and 4.7%, 7.8% and 14.6%, and 2.9% and 5.9%, respectively. A 10% toxicity threshold was set as the maximal tolerable inhibition (MTI) for effective soil toxicity assessment. Nitrifying bacteria bioassays offer a fast, affordable, and user-friendly tool for real-time soil toxicity assessment, boosting soil health monitoring and ecosystem protection. Full article

Achieving carbon neutrality requires a comprehensive understanding of terrestrial carbon dynamics, particularly the capacity of ecosystems to act as carbon sinks. This study quantified the temporal and spatial variability of net primary production (NPP) and net ecosystem production (NEP) across South Korea from 2010 to 2024, assessing long-term carbon sink trends and their implications for carbon neutrality and nature-based solutions (NbSs). Using the Carnegie–Ames–Stanford Approach (CASA) model driven by Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data and climate variables, we estimated ecosystem carbon fluxes at high spatial and temporal resolutions. In 2024, national NPP totaled 78.63 Mt CO₂ yr⁻¹, with a mean value of 1956.63 t CO₂ ha⁻¹ yr⁻¹. High productivity was concentrated in upland forests of Gangwon-do, Mt. Jirisan, and northern Gyeongsangbuk-do, where favorable vegetation indices and climatic conditions enhanced photosynthesis. Lower productivity occurred in urbanized areas and intensively farmed lowlands. Heterotrophic respiration (RH) was estimated at 15.35 Mt CO₂ yr⁻¹, with elevated rates in warm, humid lowlands and reduced values in high-elevation forests. The resulting NEP in 2024 was 63.29 Mt CO₂ yr⁻¹, with strong sinks along the Baekdudaegan Range and localized negative NEP pockets in lowlands dominated by urban development or agriculture. From 2010 to 2024, the spatially averaged NPP increased from 1170 to 1543 g C m⁻² yr⁻¹, indicating a general upward trend in ecosystem productivity. However, interannual variability was influenced by climatic fluctuations, land-cover changes, and data masking adjustments. These findings provide critical insights into the spatiotemporal dynamics of terrestrial carbon sinks in South Korea, offering essential baseline data for national greenhouse gas inventories and the strategic integration of NbSs into carbon-neutral policies. Full article

Plastics are essential in modern life but accumulate as waste. Mechanical reprocessing reduces material quality, whereas thermochemical routes require harsh conditions and are costly to upgrade. Together, these factors hinder the large-scale recovery of plastics into equivalent materials. Metal–organic frameworks provide a programmable platform where reticular design fixes porosity and positions well-defined Lewis, Brønsted, redox, and photoredox sites that can preconcentrate oligomers and align scissile bonds for activation. These attributes enable complementary pathways spanning hydrolysis, alcoholysis, aminolysis, photo-oxidation, electrocatalysis, and MOF-derived transformations, with adsorption-guided capture-to-catalysis workflows emerging as integrative schemes. In this review, we establish common figures of merit such as space–time yield, monomer selectivity and purity, energy intensity, site-normalized turnover, and solvent or corrosion footprints. These metrics are connected to design rules that involve active-site chemistry and transport through semi-crystalline substrates. We also emphasize durability under hot aqueous, alcoholic, or oxidative conditions as essential for producing polymer-grade products. Full article

The present study developed and evaluated an integrated disaster nursing education program combining functional training and simulator-based learning to address limitations of traditional, theory-driven approaches. Overall, 49 senior nursing students completed the program using a four-stage repeated-measures design. The findings indicated a substantial enhancement in disaster nursing knowledge over time. However, problem-solving ability, learning self-efficacy, and motivation exhibited improvement only in post hoc comparisons. This contradictory yet fundamental finding suggests that knowledge acquisition occurs more directly, whereas problem-solving and motivational competencies require cumulative practice, feedback, and contextual immersion. Educator reflections and student debriefings further underscored the significance of teamwork, communication, and scenario relevance in facilitating learning transfer. Despite its limitations, including a single-site, female-dominated sample, reliance on self-reported measures, and a brief follow-up period, this study makes a significant contribution to the field of disaster nursing education by presenting a sustainable and adaptable model. Incorporation of multi-institutional and longitudinal designs, as well as qualitative analyses of learning processes will be crucial in future studies. This will ensure the study’s generalizability and long-term impact. Full article

Wharton’s Jelly-derived mesenchymal stem cell (WJ-MSC) secretome contains diverse bioactive factors with potential for skin regeneration, but its clinical efficacy is limited by poor transdermal delivery. In this study, we developed a dual-delivery system by nanoencapsulating WJ-MSC secretome and coating it onto marine sponge-derived spicules. Physicochemical characterization, in vitro assays (fibroblast and keratinocyte proliferation, keratinocyte migration, type I procollagen secretion, and antioxidant activity), and in vivo penetration studies were conducted. A single-arm clinical trial evaluated dermal absorption, pore characteristics, skin texture, wrinkles, and pigmentation following topical application. Transdermal penetration efficiency was significantly higher in the nano-coated spicule group than in the uncoated secretome control. In vitro, secretome treatment promoted fibroblast and keratinocyte activity, accelerated wound closure, and increased collagen synthesis. Clinically, a single application enhanced dermal absorption and significantly reduced pore number, while two weeks of treatment decreased wrinkles and pigmentation. Spicule-based nanoencapsulation effectively overcomes the skin barrier, enhances the regenerative activity of WJ-MSC secretome, and induces measurable clinical improvements in skin rejuvenation. This platform represents a promising cosmetic and therapeutic strategy in dermatology. Full article

Lipid nanoparticles are a clinically validated platform for delivering nucleic acids, but performance is constrained by multiscale physiological barriers spanning circulation, vascular interfaces, extracellular matrices, cellular uptake, and intracellular trafficking. This review links composition–structure–function relationships for ionizable lipids, helper phospholipids, cholesterol, and PEG-lipids to systemic fate, endothelial access, endosomal escape, cytoplasmic stability, and nuclear transport. We outline strategies for tissue and cell targeting, including hepatocyte ligands, immune and tumor selectivity, and selective organ targeting through compositional tuning, together with approaches that modulate escape using pH-responsive chemistries or fusion-active peptides and polymers. We further examine immunomodulatory co-formulation, route and schedule effects on biodistribution and immune programming, and manufacturing and stability levers from microfluidic mixing to lyophilization. Across these themes, we weigh trade-offs between stealth and engagement, potency and tolerability, and potency and manufacturability, noting that only a small fraction of endosomes supports productive release and that protein corona variability and repeat dosing can reshape tropism and clearance. Convergence of standardized assays for true cytosolic delivery, biomarker-guided patient selection, and robust process controls will be required to extend LNP therapeutics beyond the liver while sustaining safety, access, and scale. Full article

Forward head posture and altered scapular alignment are associated with musculoskeletal dysfunctions and impaired physical performance. However, the relationship between postural alignment indices and physiological function in young adults remains unexplored. A total of 54 healthy participants (mean age: 21.88 ± 2.06 years) were evaluated. Craniovertebral angle (CVA) and scapular index were measured as indicators of postural alignment. Upper trapezius muscle tone was assessed using the MyotonPRO device. Pulmonary function parameters, including the forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁)/FVC, were measured using spirometry. Balance control was evaluated using the Tetrax system, and cervical proprioception was assessed using joint position error (JPE) tests. CVA showed statistically significant but weak correlations with the muscle tone (r = −0.191), weight distribution index in the eyes-open condition (r = −0.199), and cervical flexion JPE (r = −0.198) and a positive correlation with FVC (r = 0.251) (p < 0.05). Scapular index showed a positive correlation with FEV₁/FVC (r = 0.241) and a negative correlation with balance control (r = −0.213) (p < 0.05). Improved postural alignment, as reflected by a higher CVA and scapular index, was associated with reduced muscle tone, enhanced pulmonary function, better balance control, and more accurate cervical proprioception. Full article

This study investigated the optimization of optical film configurations to mitigate angular color deviation—a persistent challenge in quantum dot (QD) backlight displays. A white backlight was implemented by placing a yellow CdSe-based QD film on a blue edge-lit backlight, followed by various combinations of prism and diffusion films. Optical characteristics, including luminance, spectral distribution, and chromaticity coordinates, were systematically measured over a viewing-angle range of −70° to 70° for different film arrangements. Applying one or two prism films significantly enhanced normal luminance and improved color conversion efficiency by forming vertical optical cavities; however, this also introduced the side-lobe phenomenon, leading to color non-uniformity. Placing a diffusion film between the QD and prism films did not resolve these issues, whereas positioning it as the topmost layer above the prism films effectively eliminated color dispersion and produced a uniform luminance distribution. These results provide practical design guidelines for optimizing optical film stacks in QD-enhanced backlight units to achieve superior color uniformity in LCD displays. Full article

This study examined the physiological development of the red-fleshed peach cultivar ‘Daehong’ at different stages of fruit maturation to determine the optimal harvest time. Fruit samples were collected at five intervals—50, 80, 100, 120, and 140 days after full bloom (DAFBs)—and evaluated for external attributes (weight, size, and color) and internal attributes (soluble solids, sugar–acid ratio, firmness, sugars, and organic acids). Internal quality parameters, including soluble solids content and firmness, reached commercially acceptable levels at 120 DAFB. Sucrose was the predominant sugar, increasing steadily during maturation, while malic acid levels declined, resulting in an improved sugar–acid balance. Respiratory activity and ethylene production peaked at 140 DAFB, marking the onset of full ripening. Additionally, Hunter a* values and anthocyanin content increased progressively, intensifying the red coloration of the fruit. Principal component analysis (PCA) indicated that overall fruit quality was highest between 120 and 140 DAFB; however, reduced firmness at later stages suggests that delayed harvesting could impair postharvest storability. Considering both physiological indicators and climate variability, harvesting ‘Daehong’ peaches when growing degree days (GDDs) approach 1800 °C is recommended, as this provides a more consistent and objective maturity index than DAFB alone. Full article

This research examines the factors influencing drop out among adult college students. As the traditional-age student population (ages 19–24) declines, the older, part-time, adult learners have emerged as a critical enrollment demographic for higher education institutions. These learners often pursue higher education for career advancement, re-skilling, or re-employment. However, many encounter difficulties in sustaining their academic engagement due to low motivation, limited basic learning skills, or external constraints. Despite the growing presence of adult learners in Korean universities, limited research has analyzed drop-out factors within this specific context. To address this gap, this study applies Bean and Metzner’s nontraditional undergraduate student attrition model, using data from the Korean Educational Longitudinal Study (KELS). It investigates how background characteristics, academic variables, environmental factors, and academic and psychological outcomes influence the drop out of adult learners. The findings reveal that academic variables significantly impact drop-out intentions, while student engagement and social integration show minimal effects. These results offer valuable theoretical insights and practical implications for enhancing adult learner retention in higher education. Full article

This study presents the development and the mechanical and clinical characterization of a flexible biodegradable chitosan–glycerol–graphite composite strain sensor for real-time respiratory monitoring, where the main material, chitosan, is derived and extracted from Tenebrio Molitor larvae shells. Chitosan was extracted using a sustainable, low-impact protocol and processed into a stretchable and flexible film through glycerol plasticization and graphite integration, forming a conductive biocomposite. The sensor, fabricated in a straight-line geometry to ensure uniform strain distribution and signal stability, was evaluated for its mechanical and electrical performance under cyclic loading. Results demonstrate linearity, repeatability, and responsiveness to strain variations in the stain sensor during mechanical characterization and performance, ranging from 1 to 15%, with minimal hysteresis and fast recovery times. The device reliably captured respiratory cycles during normal breathing across three different areas of measurement: the sternum, lower ribs, and diaphragm. The strain sensor also identified distinct breathing patterns, including eupnea, tachypnea, bradypnea, apnea, and Kussmaul respiration, showing the capability to sense respiratory cycles during pathological situations. Compared to conventional monitoring systems, the sensor offers superior skin conformity, better adhesion, comfort, and improved signal quality without the need for invasive procedures or complex instrumentation. Its low-cost, biocompatible design holds strong potential for wearable healthcare applications, particularly in continuous respiratory tracking, sleep disorder diagnostics, and home-based patient monitoring. Future work will focus on wireless integration, environmental durability, and clinical validation. Full article