Earticle

Anthraquinones are secondary metabolites of plants and are widely distributed in vari-ous species. They are known to exhibit a wide range of biological activities, including anticancer, anti-inflammation, antioxidant, antibacterial, anti-damage, and anti-osteoporosis. Anthraquinones are generally lipophilic, which results in relatively low solubility and bioavailability. These limita-tions can be addressed through enzymatic reactions such as glycosylation and hydroxylation. In this study, we attempted the glycosylation of two anthraquinone compounds, anthraflavic acid and xanthopurpurin, using microbial UDP-glycosyltransferase UGT-1. UGT-1 could catalyze the O-glu-cosylation of anthraquinones to form glucoside-type products, which were confirmed by HPLC and high-resolution LC-MS analyses. This study demonstrates that glycosyltransferase UGT-1 could be a good candidate for producing modified anthraquinones with poogical activtential biolities

We are trying to apply surface stress improvement process (SSIP) to the repair and maintenance of nuclear power components, mainly in the United States and Japan. A representative example is applying water jet peening (WJP) and laser peening (LP) technology to parts to extend their lifespan. The biggest problem with the lifespan of nuclear power equipment is the occurrence of stress corrosion cracking (SCC), which is directly related to safety. The SSIP is one of the good ways to mitigate SCC. The Code Case N-931 “Performance and Qualification Criteria for Mitigation of Stress Corrosion Cracking by Surface Stress Improvement: Section III, Division 1 and 3’ was developed since 2017 by the task group “Advanced Surface Stress Improvement Technology” in Korea International Working Group (KIWG) of the American Society of Mechanical Engineers (ASME). This case provides performance and qualification criteria for the pre-service application of a SSIP to items potentially susceptible to SCC, as a means to prevent crack initiation. Mitigation of items to the requirements of this case does not modify or change the in-service inspection (ISI) requirements for those items. This Code Case is to be used for SSIP such as ultrasonic nanocrystal surface modification (UNSM), WJP, LP that satisfy the performance criteria and qualification criteria defined in this case. Two major technical bases for this Code Case are “PVP2022-85151” and “EPRI Report 3002018458”. Brief summary of UNSM technology and two technical bases is introduced.

Trehalose is a naturally occurring disaccharide that is abundantly present in nature. Its presence in cells as several effects, especially because it acts as a natural defender of proteins and membranes. It is utilized in food, cosmetics, and medications because of its excellent water retention properties. Following its esterification with fatty acids of different chain lengths, trehalose has also been shown to have anti-bacterial, anti-biofilm, and anti-inflammatory properties. Trehalose plays a structural part in the bacterial cell wall’s adaptive reactions to stressors including osmotic variations high temperature. Additionally, it was proposed that when bacterial cells are exposed to harsh environment challenges such as heat, cold, desiccation, or reactive oxygen species, these organisms biosynthesize high concentrations of both intra- and extracellular trehalose to help them to survive. Therefore, we analyzed Variovorax sp. PAMC28711 isolated from Antarctica, which was predicted by bioinformatics tools (RAST, Prokka, KEGG, CGView Server, and MetaCyc) to predict the enzymes involved in the different pathways of trehalose production. Furthermore, TLC analysis was carried out to characterize various trehalose biosynthesis pathways. According to the findings, it was revealed that our polar bacteria Variovorax sp. PAMC28711 have potential to produce trehalose through three (Trehalose-6 phosphate synthase/trehalose-6-phosphat phosphatase, Trehalase synthase, and Maltooligosyl-trehalose synthase/maltooligosyl-trehalose trehalohydrolase) pathways. We anticipate that this strain could be of potential use for manufacturing trehalose on the industrial scale.

Aluminum alloys are extensively used in civil aircraft due to their lightweight, high strength, and excellent formability. However, their susceptibility to corrosion and corrosion fatigue poses a significant maintenance challenge in aviation environments. This study explores the effec-tiveness of ultrasonic nanocrystal surface modification (UNSM) technology in enhancing the corro-sion fatigue strength of Al7075-T6 alloy. Specimens were subjected to controlled corrosion condi-tions and treated with UNSM either before or after corrosion exposure. Corrosion fatigue tests re-vealed that UNSM treatment significantly increased fatigue life—by over 140 times compared to untreated corroded specimens—by inducing deep compressive residual stress, increasing surface hardness, and refining surface structure. These results highlight UNSM's potential to delay crack initiation and propagation in corrosive environments, offering a promising surface enhancement strategy for aircraft aluminum alloys.

This study proposes a methodology to interpret cylindrically propagating elastic waves as analogous to waves propagating in Cartesian coordinates. By employing coordinate transfor-mations and leveraging the symmetry of wave propagation, the approach simplifies the complexi-ties inherent in cylindrical coordinate systems. This framework enables the application of existing Cartesian-based analytical techniques to cylindrical wave problems, providing enhanced computa-tional efficiency. The proposed method holds potential for various engineering applications, includ-ing elastic wave-based nondestructive testing and structural optimization, particularly in complex media and structures.