Mesenchymal stem cells (MSCs) are primary candidates for cell therapy and tissue engineering applications. A two-dimensional (2D) culture system is typically used for cell growth, but that method affects the characteristics of stem cells. The physiological cell environment connects cells not only to each other, but also to the extracellular matrix providing mechanical support, exposing the entire cell surface, and opening signaling pathways. The hanging drop method is the most widely used 3D culture method for spheroid formation. In this study, we investigated the relationship between spheroid size and changes in gene expression to determine the optimum spheroid size for use in tissue engineering. The expression levels of stemness factors such as NANOG, OCT4, and SOX2, angiogenic factors such as VEGF and IL-8, and osteogenic factors such as COX2 and TGF-β1 increased with spheroid size in the respective spheroid formation groups unlike the responses in their monolayer groups. Therefore, our results indicate that spheroid formation through the hanging drop method can increase the efficiency of MSCs-based tissue engineering over that obtained via traditional 2D cell culture systems.

Lithium ion battery are one of representative rechargeable batteries with high energy density, tiny memory effect, and low self-discharge and composed of anode, cathode, electrolyte, and membrane separator. The importance of membrane separator has been improved further as electric vehicle market increases rapidly. The conventional membrane separators are based on polyolefin (e.g., polyethylene and/or polypropylene). In case of lithium ion battery with a high capacity, polyolefin membrane separators are suffering from low thermal resistance and easy short-circuit formation leading to overheating. For these reasons, in this study, gel polymers are in-situ synthesized in electrolytes used as solvent, which are located in pores of polyolefin separators to obtain gel polymer electrolyte-polyolefin reinforced membranes.

수처리용 분리막 시스템의 경우, 생물막 형성됨에 따라 분리막의 효율성이 저해된다. 이러한 문제를 완화 시키고자 생물막 형성을 방해하는 정족수 감지 억제 기술이 연구 되고 있다. 본 연구에서는 미생물의 내생기작과 외생기작을 각각 적용하여 생물막 저감 효과를 한 줄로 구성된 중공사막 모듈과 다발형 모듈에서 비교하였다. 그 결과 한 줄로 구성된 모듈에서는 내생기작과 외생기작이 미생물 생성 억제 성능에 큰 차이가 없었지만, 다발형 모듈에서는 외생 기작이 더 효과적인 것으로 나타났다. 따라서 다발형 모듈로 구성된 실제 중공사 수처 리 시스템에서는 외생 기작을 가진 정족수 감지 억제 미생물을 사용하여 분리 막 표면에 생기는 생물막을 저감하는 것이 내생 기작을 가진 미생물을 적용하는 것 보다 효율적인 것으로 보여진다.

Shale gas has become increasingly important as a viable alternative to conventional gas resources. However, one of the critical issues in the development of shale gas is the generation of produced water, which contains high concentration of ionic compounds (> TDS of 100,000 mg/L). Accordingly, membrane distillation (MD) was considered to treat such produced water. Experiments were carried out using a laboratory-scale direct contact MD (DCMD). Synthetic produced water was prepared to examine its fouling propensity in MD process. Antiscalants and in-line filtration were applied to control fouling by scale formation. Fouling rates (-dJ/dt) were calculated for in-depth analysis of fouling behaviors. Results showed that severe fouling occurred during the treatment of high range produced water (TDS of 308 g/L). Application of antiscalant was not effective to retard scale formation. On the other hand, in-line filtration increased the induction time and reduced fouling.

Ionic liquids (ILs) have been used in DNA extraction/separation, DNA preservation and PCR based on their characteristic affinity to DNA. However, few studies have been performed about how DNA-IL complex forms and its mechanism which would be essential to understand the role of ILs over the range of applications. Herein, we present that the differences in the structure of the DNA- IL complex are associated with the alkyl chain length of IL. The assumption was evidenced by Atomic force microscopy, DNA specific dye staining, gel-electrophoresis and real-time electrical measurement. We observed unique electrical signals with altered duration time and amplitude when DNA- ILs complexes pass through solid-state nanopore. We examined three types of ILs (EMIM-Cl, BMIM-Cl, and OMIM-Cl) for their characteristics to form DNA-ILs complexes. The results indicated that the length of hydrophobic alkyl group in respective ILs determines the form of DNA-IL complex. In conclusion, the morphology of DNA could be modified by the incorporation with different alkyl chain length of ILs, providing their further application in biosensor such as nanopore technique for DNA sequencing or understanding protein-DNA interaction.

Nine species of fossil plants were described based on the new material collected from the Hasandong Formation. They are as follows: Thallites yabei, Onychiopsis elongata, Cladophlebis denticulata, C. shinshuensis, C. (Eboracia ?) lobifolia, C. (Klukia ?) koraiensis, Brachyphyllum japonicum, Elatocladus tennerima, and Taeniopteris ? sp. cf. T. auriculata. The floristic composition of the Hasandong flora is very similar to that of the Nakdong flora. This means that both floras might have flourished under subtropical warm arid climate. This flora contains both the Tetori-type and Ryoseki-type floras. It is considered that the Hasandong flora is a member of the Mixed-type floras that existed in eastern Eurasia during the Late Jurassic to Early Cretaceous time.