Effect of Elastic Network of Ceramic Fillers on Thermal Cycle Stability of a Solid Oxide Fuel Cell Stack

Glass‐based seals for planar solid‐oxide fuel‐cell (SOFC) stacks are open to uncontrolled deformation and mechanical damages, limiting both sealing integrity and stack reliability, particularly in thermal cycle operations. If the glass‐based seals work like an elastomer‐based compressive seal, SOFC stacks may survive unprecedented numbers of thermal cycles. A novel composite sealing gasket is successfully developed to mimic the unique features of the elastomer‐based compressive seal by controlling the composition and packing behavior of binary ceramic fillers. A single‐cell SOFC stack undergoes more than 100 thermal cycles with little performance loss, during which the sealing integrity is lost/recovered repeatedly upon cooling and reheating, corresponding to unloading/loading of the elastomer‐based compressive seal. The thermal‐cycle responses of the SOFC stack are explained in sequence by the concurrent events of elastic deformation/recovery of ceramic filler network and corresponding redistribution of sealing glass.     

Degradation of Cochlodinium polykrikoides using photocatalytic reactor with TiO2-coated alumina

Cochlodinium polykrikoides (C. polykrikoides) is one of the most harmful red tide dinoflagellates due to its great economic damage and compromising recreational opportunity and public health. Titanium dioxide (TiO₂) is known to be used as a photocatalyst for the control of the aquatic invasive algae under natural and artificial light. The purpose of this study was to design a highly efficient continuous photocatalytic reactor with TiO₂-coated alumina for the demonstrated efficient degradation of C. polykrikoides. TiO₂ photocatalyst beads were prepared by sol-gel dip-coating method using titanium tetra iso-propoxide on alumina. After 40 min of ultraviolet illumination time, the reduction of C. polykrikoides cell number was more than 80%. The degree of degradation of C. polykrikoides increased in a time-dependent manner in this novel reactor. The degradation begins with photocatalytic action by the oxidative species of TiO₂ on the protective cell structures of C. polykrikoides.     

Infection status of the sea eel (Astroconger myriaster) purchased from the Noryangjin fish market with anisakid larvae]

Although the sea eel (Astroconger myriaster) is suspected as one of the most important fish host for human anisakiasis in Korea, no report has been made on the infection status of the sea eel with anisakid larvae. In the present study, 26 sea eels (Astroconger myriaster) were purchased from the Noryangjin fish market in Seoul, and anisakid larvae were collected from their viscera, muscle, head and skin. The collected larvae were classified by their morphological types. A total of 1,351 anisakid larvae were collected from 15 of 26 fish examined. Among them, 1,269 were recovered from the viscera, 66 from the muscle, and 16 from the head and skin. Morphologically, most of the anisakids were classified into 6 known larval types, Anisakis type I (564 larvae) of Berland (1961), Contracaecum type A (409) and type D (5) of Koyama et al. (1969), Contracaecum type C' (83) and type D' (117) of Chai et al. (1986), and Contracaecum type V (1) of Yamaguti (1935). Remaining 172 specimens were new in the available literature, hence, designated as Contracaecum type A' (new type). The present results revealed that the sea eels caught in the Korean waters are heavily infected with anisakid larvae, not only in their viscera but also in the muscle, and Anisakis type I was the most common among the 7 larval types.     

Demethylation and derepression of genomic retroelements in the skeletal muscles of aged mice

Changes in DNA methylation influence the aging process and contribute to aging phenotypes, but few studies have been conducted on DNA methylation changes in conjunction with skeletal muscle aging. We explored the DNA methylation changes in a variety of retroelement families throughout aging (at 2, 20, and 28 months of age) in murine skeletal muscles by methyl‐binding domain sequencing (MBD‐seq). The two following contrasting patterns were observed among the members of each repeat family in superaged mice: (a) hypermethylation in weakly methylated retroelement copies and (b) hypomethylation in copies with relatively stronger methylation levels, representing a pattern of “regression toward the mean” within a single retroelement family. Interestingly, these patterns depended on the sizes of the copies. While the majority of the elements showed a slight increase in methylation, the larger copies (>5 kb) displayed evident demethylation. All these changes were not observed in T cells. RNA sequencing revealed a global derepression of retroelements during the late phase of aging (between 20 and 28 months of age), which temporally coincided with retroelement demethylation. Following this methylation drift trend of “regression toward the mean,” aging tended to progressively lose the preexisting methylation differences and local patterns in the genomic regions that had been elaborately established during the early period of development.