The commercial feed additive, native rumen microbes (RC), derived from a diverse microbial community isolated from the rumen of Hanwoo steers is being explored to enhance rumen fermentation and improve ruminant feed utilization. This study evaluated the impact of native rumen microbes supplementation on methane emissions, microbial diversity, and fermentation efficiency on in vitro assessment. Treatments were as follows: CON (basal diet, without RC); T1 (basal diet + 0.1% RC); T2 (basal diet + 0.2% RC). Rumen fermentation parameters, total gas, and methane production were assessed at 12, 24, and 48 h of incubations. The in vitro gas production was carried out using the Ankom RF Gas Production System. Supplementation of RC significantly reduced the total gas production at 12, 24, and 48 hours of incubation (p < 0.05). Volatile fatty acid concentrations were increased, while acetate and propionate were decreased (p < 0.05) at 48 h by the supplementation of RC. Notably, the 0.1% inclusion level of RC significantly reduced methane production by 28.30% and 21.21% at 12 and 24 hours. Furthermore, microbial diversity analysis revealed significant shifts (p < 0.05) in bacterial composition between the control and treatment groups, while supplementation also promoted the growth of bacterial populations, such as Succiniclasticum. These findings suggest that native rumen microbes supplementation, particularly at 0.1% inclusion level, can enhance rumen microbial composition while significantly reducing methane production in vitro.

The Indian Ocean is the second-largest tuna fishing ground in the world, accounting for approximately 1.2 million tonnes (23%) of the estimated 5.2 million tonnes of global commercial tuna catch in 2023. This study examined the relationship between tuna catches, specifically skipjack, bigeye, and yellowfin tunas, and prey biomass (Nautical Area Scattering Coefficient, NASC) estimated from acoustic surveys conducted in the southwestern Indian Ocean from 20 April to 15 May 2019. Environmental variables were derived from the Copernicus Ocean Model, and tuna length data from the IOTC. The estimated total tuna catch in the study area was approximately 166,400 tonnes, with the northwestern region showing the highest catches and NASC values. Tuna catches increased with NASC; however, the relationship was non-linear. While skipjack showed no significant correlation with NASC, bigeye and yellowfin tunas exhibited weak but significant positive correlations. Environmental analysis revealed that the northern waters had high surface temperatures, low salinity, and low oxygen levels, with mid and deep layers characterized by low temperature, salinity, oxygen, and chlorophyll. These findings offer a foundation for understanding tuna distribution in relation to prey and environmental conditions, highlighting the need for future species- and fishery-specific studies to support sustainable tuna resource management.

This study aimed to enhance the operational efficiency and safety of offshore eel trap fisheries by developing six types of automated fishing equipment: a bait crusher, bait cutter, main line arranging device, trap cleaning device, eel sorting device, and fish pump system. Sea trials demonstrated that the bait crusher and bait cutter significantly reduced manual labor and processing time while maintaining bait quality. The main line arranging device improved productivity and safety by automating the sorting of looped cords. The trap cleaning device effectively removed fouling organisms using high-pressure water and rotating brushes. The eel sorting device enabled automatic size-based selection, improving resource management and operational efficiency. The fish pump system transferred eels rapidly with minimal physical damage, reducing unloading time by over 80% and decreasing labor requirements. A satisfaction survey of fishery participants confirmed that all developed devices were highly effective in reducing workload, enhancing safety, and improving operational performance. The automated equipment developed in this study is expected to contribute to the sustainable management of offshore eel trap fisheries and to offer potential applicability to other coastal and offshore fisheries.

This study examined the offshore eel trap fishing process using one year of fishing logs and fishermen’s insights to identify key operational challenges and propose equipment improvement for greater efficiency and safety. Conger eel catches varied significantly by season, depth, and temperature, peaking in winter at 85–90 m and 23°C. The western waters of Jeju Island were identified as a major fishing ground, with the highest catch recorded in November and the lowest in July, reflecting seasonal trends. Each fishing operation deployed about 10,000 traps, with an average loss of 38 traps, posing economic concerns. The process involved intensive manual labor in bait preparation, trap retrieval, catch separation, line loading, and unloading, leading to high physical demands and safety risks. To address these issues, the study proposed automation through the development of a line loading device, trap cleaning device, bait processing machine, and automatic catch separator. These innovations could reduce the labor force required by one to two workers per process, alleviate workloads, and enhance resource management. By integrating quantitative logbook analysis with field-based knowledge, this study offers practical value. Further research is recommended on automation development, cost-effectiveness, and field validation to support safer and more sustainable eel trap fisheries.

Moringa oleifera, a versatile plant, has been traditionally used to treat various ailments and is gaining scientific attention due to its potential as a medicine. Native to the Indian subcontinent, it is widely grown in tropical and subtropical regions, thriving in Asia, Africa, and South America, especially in arid climates. This study explores the antioxidant potential of Moringa oleifera leaf extract (MOLE), employing a comprehensive screening approach with various solvents to identify the most effective extraction method. Initial experiments assessed antioxidant efficacy and yield using distilled water (D.W.), 95% ethanol, and 95% methanol. Among these, 95% ethanol extract demonstrated superior antioxidant activity, confirmed through assays such as 2,2-diphenyl-1-14 picrylhydrazyl (DPPH) radical scavenging assay, total polyphenol content analysis, and reducing power assay. In addition, with the 95% ethanol MOLE, a higher extraction efficiency was yielded compared to other solvents, making it the most effective for large-scale preparation. HPLC analysis revealed the presence of key bioactive compounds, including ellagic acid, rutin, Q-3-O, quercetin, and kaempferol. Results revealed that MOLE, prepared using 95% ethanol, exhibited remarkable antioxidant properties, attributed to its rich polyphenolic content. This research underscores the therapeutic potential of MOLE as a natural antioxidant source and highlights the importance of solvent optimization in phytochemical extractions.

The Japanese encephalitis virus (JEV) is a zoonotic pathogen that affects the nervous systems of humans, pigs, and horses. It has been classified into five genotypes (G1-G5) based on molecular analysis of the pre-membrane or envelope gene. In the Republic of Korea, the predominant JEV genotype has recently shifted from G3 to G1 and G5, highlighting the need for a rapid and accurate diagnostic method. In this study, we designed specific common and differential primer sets for JEV G1, G3, and G5 to detect the JEV gene. Four specific primer sets for JEV G1, G3, and G5 were used to selectively amplify the target gene. The detection limits of the common primer set for JEV G1, G3, and G5 were 100, 0.1, and 10 TCID50/reaction, respectively. The detection limits of the three differential primer sets were 1, 0.1, and 1 TCID50/reaction, respectively. No cross-reactivity was observed with non-JEV reference viruses. We successfully developed a multiplex reverse transcription polymerase chain reaction (RT-PCR) assay to distinguish the three JEV genotypes. Our multiplex RT-PCR assay is highly sensitive and specific, providing a reliable tool for confirming JEV infection in suspected samples. Additionally, our assay can be applied to suspected mosquito samples and commercial veterinary biological products.

We presented foundational findings regarding the occurrence and acoustic characteristics of the finless porpoise through passive acoustic and visual surveys conducted on the southern coast of Korea, specifically at Hadong Jungpyeong Port. Over a survey period spanning from July 8 to August 16, 2023, totaling 40 days, we observed peaks in the number of clicks produced by this species on July 15, July 24, August 4, August 11, and August 16. The highest count, totaling 18,924 clicks, was recorded on July 15th, while the lowest count, at 3,888 clicks, occurred on August 8th. Examining the acoustic characteristics throughout the diurnal cycle, we found that the peak activity in terms of DPM (detection positive minute for one hour), DP10M (DPM for ten minutes), and overall number of click sounds was observed between 05:00 and 08:00, with a secondary peak occurring from 17:00 to 18:00. The quietest period was noted between 23:00 and 02:00. Furthermore, there was a significant increase in the number of clicks from sunrise, with the maximum count of 21,581 clicks recorded at 6 AM. This count gradually decreased until noon, experienced a slight increase thereafter, peaked again at sunset, and then declined. The dominant frequency mode of this species was 126 kHz, with a concentration ranging from 112 to 136 kHz. The average duration of a click sound was 127 ㎲, with approximately 16 sinusoids (cycles) within each click sound and an average cycle length of approximately 7.9 ㎲. These findings from our study are anticipated to serve as foundational data for the development of a Korean pinger and acoustic warning system.

We report a new route of akaganéite (β-FeOOH) formation and maghemite (γ-Fe2O3) formation. Akaganéite can be produced by stirring Fe2+ at room temperature for a day under mild conditions. We used FeCl2 ·4H2O as the precursor and mixed it with the Na-rich particle from the oxidation debris solution. The role of the concentration ratio between graphene oxide (GO) and NaOH was addressed to generate oxidation debris (OD) on the surface. In particular, the characterization of OD by transmission electron microscope (TEM) imaging provides clear evidence for the crystal formation of Na-rich particle under electron beam irradiation. For the base treatment process, increasing the concentration of a NaOH in Na-rich solution contributed primarily to the formation of γ-Fe2O3. The characterization by scanning electron microscope (SEM) and TEM showed that the morphology was changed from needle-like to small-oval form. In addition, β-FeOOH can be effectively produced directly using GO combined with FeCl2 ·4H2O at room temperature. More specifically, the role of parent material (Hummer's GO and Brodie's GO) was discussed, and the crystal transformation was identified. Our results concluded that β-FeOOH can be formed in basic and acidic conditions.

Recently, domestic fishing production of Japanese horse mackerel has been continuously decreasing. To achieve sustainable fishing of this species, it is essential to acquire its target strength (TS) for accurate biomass estimation and to study its ecological characteristics. To date, there has been no TS research using a broadband echosounder targeting Japanese horse mackerel. In this study, for the first time, we synchronized an underwater camera with a broadband frequency (nominal center frequency of 200 kHz, range: 160-260 kHz) to measure the TS according to the body size (16.8-35.5 cm) and swimming angle of the species. The relationship between Japanese horse mackerel length and body weight showed a general tendency for body weight to increase as length increased. The pattern of the frequency spectra (average values) by body length exhibited a similar trend regardless of body length, with no significant fluctuations in frequency observed. The lowest TS value was observed at 243 kHz while the highest TS values were recorded at 180 and 257.5 kHz. The frequency spectra for the swimming angles appeared to be flat at angles of –5, 0, 30, 60, 75, and 80° while detecting more general trends of frequency spectra for swimming angle proved challenging. The results of this study can serve as fundamental data for Japanese horse mackerel biomass estimation and ecological research.

Integration of noble metals on graphene is renowned for their catalytic and antioxidant prowess. However, utilization of toxic chemicals in the synthesis creates environmental pollution and poisonous nature of chemically synthesized materials. To address this, an economical and eco-friendly method for synthesizing graphene-gold (BRG-Au) nanocomposite by anchoring gold nanoparticles (Au NPs) onto reduced graphene oxide sheets using betel leaf extract as a reducing and stabilizing agent is presented. Comprehensive structural characterizations through UV–Visible, Raman, FT-IR, and XRD analyses confirm the successful formation of the BRG-Au nanocomposite. Morphological assessments utilizing FE-SEM and TEM techniques revealed the presence of transparent, twinkling graphene sheets embellished with 20 to 60 nm of Au NPs in various shapes, including spherical, triangular, pentagonal, circular, and trapezoids. The catalytic and antioxidant activities of the BRG-Au nanocomposite were thoroughly evaluated. In catalytic trials, the nanocomposite exhibited remarkable efficiency in the reduction of 4-nitrophenol to 4-aminophenol, accomplishing this transformation within a mere 30 min during the initial cycle and maintaining stable catalytic performance over three consecutive cycles. Additionally, antioxidant analyses employing Total Antioxidant Activity and 2,2-diphenyl-1-picrylhydrazyl methods demonstrated that BRG-Au nanocomposite possessed equal or superior antioxidant activity than the ascorbic acid standard. This research thus underscores the promising potential of environmentally benign synthesis method for graphene-gold nanocomposite with enhanced catalytic and antioxidant properties.

This study investigated speaking anxiety among advanced Korean language learners in Korean Language Institution classrooms, and the strategies they used to overcome it. The study employed qualitative methodology using online interviews for data collection. The sampling technique involved purposive sampling by selecting 13 Korean learners who had completed an advanced Korean course at TOPIK Levels 5 or 6, with Level 6 being the highest. The interview questions addressed various aspects, including comparisons of speaking skills, anxiety in Korean classrooms, fear of making mistakes, concerns about classmates’ reactions, and anxiety induced by teachers. Thematic analysis was performed by generating initial codes, grouping related codes to uncover potential themes, and highlighting recurring patterns in the participants’ responses. The results revealed three factors that contribute to speaking anxiety: personal reasons, teachers’ classroom approaches, and teaching methods. Advanced learners manage anxiety through three coping strategies: preparation, positive thinking, and seeking support from peers. The study concludes with discussions on the pedagogical implications, limitations, and recommendations for future research in advanced Korean language learning classrooms.