The stabilization technology for the damaged spent fuel is being developed to process the damaged fuel into sound pellet suitable for dry re-fabrication. It requires several treatments including oxidative decladding followed by reduction treatment for oxidized powder closely related to the quality of oxidized powders for pellet fabrication. For the development of operating condition for the reduction treatment, in this study, we evaluated the effect of air-cylinder based vertical shaking previously applied to oxidative decladding on powder reduction. For U3O8 of 50-100 g, the reduction test were applied with and without vertical shaking at 700°C under reduction atmosphere (Ar + 4%H2) and the concentration of hydrogen in effluent was measured to evaluate the reduction reaction. It was found that the vertical shaking system has allowed the reaction time of 50 g and 100 g U3O8 reduced by 33% compared to the test in static mode. Based on XRD analysis, the better crystallinity of the products was also achieved.

The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform the fuel material recovery from damaged fuel rods by oxidative decladding technology. As driving forces to accelerate oxidative decladding rate, magnetic vibration and pulse hammering generated by a pneumatic cylinder were used in this study. The oxidative decladding efficiency and recovery rate of fuel oxide powder with rod-cut length, oxidation temperature and time, oxygen concentration, and gas mixtures were investigated using simfuel rod-cuts in a vertical furnace for fuel material recovery and powder quality improvement. The oxidative decladding was performed for 2.5-10 h as following operation parameters: simfuel rod-cut length of 50-200 mm, oxidative temperature from 450 to 580°C, oxygen concentration of 49.5 or 75.6%, and gas mixtures in O2/Ar or O2/N2. In magnetic vibration, oxidative decladding was progressed only at bottom portion of fuel rodcut. Whereas, oxidative decladding in pulse hammering was occurred at both top and bottom portions of fuel-rod. In pulse hammering method, the oxidative decladding conditions to declad rod-cuts of 50- 200 mm in length were established to achieve both decladding efficiency of ~100% and fuel material recovery rate of > 99%. These conditions were as follows: oxidation temperature and time at 500°C and 2.5-10 h, oxygen concentration at 75.6% under O2/N2 gas mixtures. As operation conditions for a pneumatic cylinder, stroking, actuating, and waiting times were 0.5, 3, and 12 s.

Suncheon Bay Ecological Park, possessing abundant fisheries and biological diversity, was registered as a Ramsar wetland in Korea. Approximately 300 bacterial strains were isolated from the Suncheon Bay in a comprehensive study of indigenous prokaryotic species conducted during 2019-2020 in South Korea. A total of 12 bacterial strains were identified using 16S rRNA gene sequencing, demonstrating >98.7% sequence similarity with validly published species. These species were determined to be unrecorded bacterial species in Korea. A total of six strains were isolated from brackish water and Phragmites communis Trin (reed) species. These unrecorded species were phylogenetically diverse and belonged to three classes, six orders, and ten genera. Regarding the genus and class levels, the previously unrecorded species belonged to Jiella, Martelella, Rhizobium, Paracoccus, Rhodovulum, and Altererythrobacter of the class Alphaproteobacteria; Mycolicibacterium, Demequina, and Microbacterium of the class Actinobacteria; Confluentibacter of the class Flavobacteria. The twelve species were further characterized by gram staining, colony and cell morphology, biochemical properties, and phylogenetic position.

The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform both fuel material recovery from damaged fuel rods by oxidative decladding and sinterability improvement of fuel powder by repetition of oxidative and reaction treatment. A horizontal type furnace provides only a diffusion-controlled reaction resulting in longer reaction time and decreasing amount of powder for oxidation and reduction, whereas a vertical type furnace with a submerged gas distributor gives rapid reaction due to flowing gas-solid contact by fluidization. For observation of fluidization behaviors of uranium oxides at room temperature, fluidized column was prepared with transparent cylindrical tube, pressure transmitter and gas flow meter. Number of size of orifice holes was determined by equations in Fluidization Engineering [D.Kunii, O. Levenspiel]. Before uranium oxide test, as surrogates, WO2 (10.8 g/cm3) and Ta2O5 (8.2 g/cm3) powder similar to density of UO2 (10.96 g/cm3) and U3O8 (8.3 g/cm3), respectively were used to achieve fluidization operation conditions in the region from minimum to expanded fluidization. Fluidization behaviors and pressure drop of powder bed was observed according to operation parameters such as gas velocity, number and size of orifice holes, and powder amount.

A eukaryotic marine microalga was isolated from Jungmun Saekdal Beach, Jeju Island, Korea and an integrated approach, including molecular phylogeny and morphology, was used to determine its taxonomical status. Molecular phylogenetic evidence inferred from the small subunit (SSU) 18S rRNA sequence and internal transcribed spacer (ITS) secondary structure analysis clearly showed that the isolate belonged to the recently described species, Jaagichlorella roystonensis. Distinctive morphological keys of the species were also observed by light microscopy and scanning/ transmission electron microscopy (S/TEM). In this study, a Korean marine J. roystonensis species was described for the first time and was subsequently added to the national culture collections in Korea.

Chlorella gloriosa (Chlorellaceae, Trebouxiophyceae) was isolated from seawater off the coast of the Dokdo Islands in Korea. An axenic culture was established using the streak-plate method on f/2 agar media supplemented with antibiotics, allowing identification of the isolate by morphological, molecular, and physiological analyses. The morphological characteristics observed by light and electron microscopy revealed typical morphologies of C. gloriosa species. The molecular phylogenetic inference drawn from the small-subunit 18S rRNA sequence verified that the microalgal strain belongs to C. gloriosa. Additionally, gas chromatography-mass spectrometry analysis showed that the isolate was rich in nutritionally important omega-3 and -6 polyunsaturated fatty acids and high-performance liquid chromatography analysis revealed that the high-value antioxidants lutein and violaxanthin were biosynthesized as accessory pigments by this microalga, with arabinose, galactose, and glucose as the major monosaccharides. Therefore, in this study, a Korean marine C. gloriosa species was discovered, characterized, and described, and subsequently added to the national culture collection.

This study aimed to examine the effect of a mild elevation in serum cholesterol level in a porcine coronary overstretch restenosis model using a balloon angioplasty catheter or drug-eluting coronary stent. Pigs were divided into two groups and were fed a commercial normal diet (CND, n = 4) or a high-fat diet (HFD, n = 4) for 5 weeks. Coronary overstretch injury by balloon angioplasty or stent implantation was induced in the left anterior descending and left circumflex artery after 1 week of feeding. Histopathological analysis was performed at 4 weeks after coronary injury. During the experiment, the total cholesterol level in the HFD group increased by approximately 44.9% (from 65.9 ± 3.21 mg/dL at baseline to 95.5 ± 9.94 mg/dL at 5 weeks). The lumen area in the CND group was reduced in comparison with that in the HFD group after balloon angioplasty. After stent implantation, the injury score showed no significant difference. There were significant differences in the neointimal area (2.7 ± 0.33 mm2 in the CND group vs. 3.3 ± 0.34 mm2 in the HFD group, p<0.05), lumen area (2.6 ± 0.54 mm2 in the CND group vs. 2.0 ± 0.33 mm2 in the HFD group, p<0.05), and percent area stenosis (52.0 ± 7.96% in the CND group vs. 62.4 ± 5.15% in the HFD group, p<0.05). Body weight change was not different between the two groups. Increased serum cholesterol level activated vascular smooth muscle cell proliferation in the porcine coronary overstretch model.

Virus-like particles (VLPs) are similar to pathogenic viruses, but because they have no nucleic acid, they have excellent safety and immunogenicity and are used as a good vaccine material. However, in the selection of various structural proteins of pathogenic viruses to form VLPs, all expression systems consume a lot of time in common. Among them, the baculovirus expression system causes additional time consumption to construct the recombinant baculovirus. Therefore, there is a need for a system that can rapidly determine the structural proteins required for effective VLP production. This study aims at solving this problem by constructing a BmNPV inducible expression platform through the construction of vectors induced by BmNPV. The platform was evaluated for overexpression using EGFP. We also confirmed the formation of virus-like particles through overexpression of canine parvovirus structural proteins.

In recent years, pavement distresses have been caused by diverse factors such as spalling, deterioration of repaired sections, blow-up, and alkali aggregate reaction due to changing climate environment of a concrete pavement and its construction and maintenance conditions (supply of materials, increase in use of de-icers, etc,). As a leading repair method for deteriorated concrete pavements, partial-depth repair is implemented in accordance with guidelines of material properties for joints of a concrete pavement and field application evaluation systems, but still some of the repaired sections become deteriorated again at an early stage due to poor construction quality and failure of response to environmental impacts. Distresses that can be corrected with partial-depth repairs are largely divided into those of repair materials and of the existing pavement bonded to repair materials, and combined distress of repair materials and the existing pavement. Although re-repair methods should be different by distress type and scale than conventional pavement repair methods, appropriate repair methods and guidance for re-repairs have not been in place so far, and therefore currently, re-repair practices follow the existing manual of partial depth repairs. Therefore, this study evaluated concrete bond characteristics by removing method and repair scope for an experimental section of frequently distressed pavements to determine a re-repair scope and method for deteriorated partial depth repair sections of concrete pavement, the number of which has increased over time.

Viral particles of Porcine epidemic diarrhea virus (PEDV) consist of a four structural proteins. Among them Spikeprotein mediated responsible for receptor binding and membrane fusion during viral infection and therefore the main targetof neutralizing antibodies. Virus-like particles (VLPs) are consisted of one or more viral structural proteins, and theirmorphologies closely resemble those of the native virus. VLPs have no virulence and can elicit robust immune responsesas compared with inactivated or live-attenuated virus vaccines. Thus, in this study, we tried two methods for VLP constructionin Bombyx mori, one is traditional method and the other is chimeric VLP method using the influenza matrix protein.Both methods could produce successfully PEDV VLPs.

Earthworms, especially Eisenia andrei, are cultivated for a variety of purposes including waste disposal and compost production. In this study, bacteria from earthworm gut were cultured and the dominant species identified. Subsequently, we isolated bacteriophages able to lyse the isolated gut bacteria. Two dominant genera of gut bacteria, Aeromonas sp. and Citrobacter sp. were identified by using MALDI-TOF MS analysis and a library was constructed to find lytic phages. Phage EF1 showed lytic activity for C. freundii and two Citrobacter isolates, C. braakii and C. murliniae. These 3 species have similar sensitivities to EF1. Several aspects of the life cycle of EF1 were investigated by using C. freundii under optimal growth conditions. EF1 infects C. freundii with a moderate latent period, approximately 25 min, and a large burst size averaging 5 × 109 per infected cell. Moreover, the antimicrobial activity of EF1 was well maintained under diverse conditions including a broad temperature range of 40°C to 50°C and a wide pH range of 4 to 11. In conclusion, the results indicate that earthworm casting contain a wide range of bacteria species, for which there are various corresponding bacteriophages.

The structural diversity and localization of cell surface glycosphingolipids (GSLs), including gangliosides, in glycolipid-enriched microdomains (GEMs) render them ideally suited to play important roles in mediating cell recognition, adhesion, interactions, receptor function, and signaling. Gangliosides, sialic acid-containing GSLs, are most abundant in the nerve tissues. The quantity and expression pattern of gangliosides in brain change drastically throughout development and these changes are mainly regulated through stage-specific expression of glycosyltransferase genes. However, roles of gangliosides in neuronal differentiation of mesenchymal stem cells (MSCs) is unclear. We previously demonstrated for the first time that the glycosyltransferase genes during mouse embryogenesis. So, we investigated the effects of ganglioside gene in differentiation of adipose-derived MSCs (AD-MSCs). GM2 and GD3 ganglioside synthease were increased during neuronal differentiation of AD-MSCs. This study showed that the differentiation of neuronal marker was decreased on the first step of ganglioside synthase UDP-glucose ceramide glucosyltransferase(UGCG) and knock downed GM2 sythase (B4GALNT1). The result of suggested that GM2 and GD3 might be important roles in the neural differentiation of mini-pig AD-MSCs. This work was carried out with the funding of the cooperative research Program for Agriculture Science & Technology Development[Project No. PJ00999901], the Rural Development Adiministration, the KRIBB Research Initiative Program[KGM4251622].