Organic complexing agents may affect the mobility of radionuclides at low- and intermediate-level radioactive waste repositories. Especially, isosaccharinic acid (ISA) is the main cellulose degradation product under high pH conditions in cement pore water. ISA can combine with radionuclides and form stable complexes that adversely influence adsorption in the concrete phase, resulting in radionuclides to leach to the near- and far-fields of repositories. This study focuses on investigating the sorption of ISA onto engineered barriers such as concrete, thereby studying adsorption isotherms of ISA on concrete and comparing various isotherm models with the experimental data. The adsorption experiment was conducted in three background solutions, groundwater (adjusted to pH 13 using NaOH), State 1 (artificial cement pore water, pH 13.3), and State 2 (artificial cement pore water, pH 12.5), in a batch system at a temperature of 20°C. Concrete was characterized using BET, Zeta-potential analyzer, XRD, XRF, and SEM-EDS. ISA concentrations were detected using HPLC. The experimental data were best fitted to one-site Langmuir isotherm; On the other hand, either two-site isotherm or Freundlich isotherm couldn’t give reasonable fitting to the experimental data. The observed ISA sorption behavior on concrete is crucial for the disposal of radioactive waste because it can significantly lower the concentration of ISA in the pore water. Although one-site Langmuir isotherm might effectively represent the sorption behavior of ISA on concrete, the underlying mechanism is still unknown, and further investigation should be done in the near future.

Natural environmental resources are considered a prospective source of microorganisms capable of producing biocatalysts with great potential in industrial areas. Arable soil fertilized with peat moss is a habitat for various microorganisms. The present research focused on the isolation and identification of hydrolase-producing bacteria that thrive at a broad temperature range. In this study, a total of 33 strains were isolated from arable soil fertilized with peat moss (Silla Garden in Busan, South Korea). The isolated bacteria were mesophiles and thermophiles with a wide temperature range. Taxonomic identification showed that the isolated strains belonged to 2 phyla, 5 families, 10 genera, and 24 species. Subsequently, the isolated strains were screened for hydrolase (amylase, lipase, and protease) activity. All isolates possessed activity of at least one enzyme and six bacterial isolates produced combined extracellular enzymes. Diversity of soil bacteria species in the present study suggest the potential of soil bacteria in the various industrial applications.

Since nuclear power plant (NPP) dismantling carries the possibility of radiation exposure from a hazardous environment, it’s important to minimize that by using a remote manipulator et al. However, due to complexity of nuclear facilities, it’s necessary for operators to increase their proficiency by operating in advance in a virtual environment. In this research, we propose a virtual manipulator system using a haptic device for NPP’s reactor vessel internals (RVI) dismantling which can realistically manipulate.

This study reports Chinese and Korean university EFL students’ perceptions of and attitudes toward online and face-to-face English language learning modes during COVID-19. Few previous studies have focused on how students thought of online and face-to-face learning experiences of subjects regarding new concept learning and delivery of new contents. Research gravitating around English courses showed students' mixed perceptions. The survey was conducted for 302 Korean and 337 Chinese university students who took communication-oriented English courses. Descriptive statistics and qualitative data analysis were used for analysis. Results indicated that students preferred face-to-face English learning with some specific indications of achieving a stronger help and quality for communicative competence in language. Online learning also benefited students with a sense of both flexibility and independence. Positive components of face-to-face learning for language education might be considered for online education while incorporation features such as flexibility and independence to enrich language education during COVID-19.

1. 본 연구는 한국-미얀마 농업분야 개발협력(ODA)의 지속 가능성 강화 방안을 분석하기 위해 2001~2017년 시계열(time series)자료를 토대로 자기회귀분포시차 모델(Autoregressive Distributed Lag, ARDL)방법과 최소자승법(Ordinary Least Square, OLS)을 사용하였다. 2. 분석결과 1) 미얀마 농업 개발에 지원된 국제사회의 ODA, 한국이 지원한 농업 분야 ODA, 농촌 개발에 대한 한국 ODA 등의 변수가 미얀마의 농업 GDP에 긍정적으로 기여한 반면, 2) 한국 ODA는 가치사슬 분야 및 기술전수 분야에 미친 영향이 부정적으로 나타났다. 이는 이 분야의 지원 규모가 매우 작아 미얀마 농업발전에 미친 영향을 측정하기 어렵기 때문인 것으로 해석할 수 있다. 또한 한국이 미얀마에 제공한 농업 ODA 중 농산물 생산 및 유통 분야에 대한 지 원은 영향이 미미한 것으로 나타났으나 양(+)의 영향을 나타 내었다. 3. 분석 결과 한국의 미얀마 대상 농업 분야 ODA는 선택과 집중을 토대로 미얀마 농업 발전에 긍정적인 영향을 미치고 있는 농촌개발 분야에 장기적으로 지원을 확대할 필요성이 있음을 확인하였다.

The growth characterization and enzyme productivity of halotolerant microorganisms isolated from the Nakdong River estuary wetland in Korea were investigated in this study. The isolation of halotolerant microorganisms was carried out through their cultivation at 37oC for several days using a marine agar medium. After a single-colony isolation, 16 pure colonies were obtained, and phylogenetic analysis was done using 16S-based ID service in the EzBioCloud database. The isolated strains were divided into 3 phyla, 5 families, 7 genera, and 13 species. Possible industrial applications of the strains were confirmed upon testing for amylolytic, lipolytic, and proteolytic activity to confirm the possible production of hydrolytic enzymes, growth at a pH range of 5 to 9, and various salt concentrations being tested. Thirteen strains possessed at least one enzyme activity, and 5 strains possessed 2 enzyme activities. Eight strains could tolerate up to 10% NaCl concentration. This result indicated that isolated strains had shown the possible application in food and cosmetic industries. Therefore, this study would contribute to securing domestic biological resources and improving hydrolytic enzyme activity using these strains.

Barnyard millet is a short-lived tropical, short-term C4 plant and has superior vitality in humid conditions owing to its freshwater habitat. It shows strong adaptability to soils with poor drainage and low fertility, and efficiently competes with rice in paddy fields. Barnyard millet grain is used as feed in the Indian region and is a great source of dietary fiber, proteins, fats, vitamins, and some essential amino acids. Considering its high nutritional value and its potential as a food resource and fodder crop, various countries are showing interest in cultivating barnyard millet. However, in Korea, farm households have not yet recognized the benefits of cultivating barnyard millet, and research regarding this is scarce. In this review, the features of forage barnyard millet and its related research trends are discussed, with the aim of improving interest in this crop and promoting its cultivation.

Lead (Pb) is a major heavy metal that augments environmental pollution and is a health risk to living organisms. This study was performed to investigate the effect of lead on characteristics of planarian, Dugesia japonica. Briefly, planarians were cultivated in water containing different concentrations (0–400 mg/L) of Pb, and incubated for varying durations (1, 3, and 5 hr). After termination of the incubation time, motility and seizure-like behaviors (c-like, head-bop, snake-like, and screw-like) of the planarians were counted in fresh water. Results showed that increasing Pb concentration and time resulted in decreased motility of the planarians (p<0.05). Increasing concentrations of Pb also resulted in significant increase in the seizure-like behavioral patterns, in particular the c-like and head-bop behaviors. In order to examine eye regeneration, the head region was cut, and rest of the body was incubated in water in the absence or presence of Pb, until emergence of the eye extrusion. Formation of eye spots was initiated in amputated fragments of the control group (without Pb) on day 4 after incubation, whereas appearance of the eye spots was delayed in planarian exposed to 200 mg/L Pb. Moreover, immunohistochemistry revealed that formation of the optic nerve was delayed in planarians exposed to Pb. Thus, our studies determined that planarians exposed to high concentrations of Pb resulted in decreasing motility and induction of seizure-like behaviors, as well as delayed eye regeneration. Results of the current study therefore validate that exposure to lead has a negative effect on the lifespan of aquatic organisms and can cause disturbance of the nervous system in animals, thereby implying the possibility of threatening health.