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Abstract In this study, concrete specimens were fabricated based on domestically manufactured materials, and long-term exposure tests were conducted in a domestic coastal environment. This study analyzes the long-term compressive strength characteristics of concrete mixed with admixtures. The mixed materials used were divided into blast furnace slag and fly ash. The blast furnace slag and fly ash were, respectively, produced by replacing ~ 30% and ~ 15% of the cement. The compressive strength was measured at 28 day, 1 year, and 10 years of age and compared with that of ordinary concrete. In addition, the long-term compressive strength results obtained in this study were compared with those of concrete mixed with admixtures reported in the literature. The strengths of the ordinary specimen at 1 year and 10 years of age increased by ~ 10 MPa and ~ 22 MPa compared with those at 28 day of age. However, concrete mixed with admixtures yielded compressive strength increases of ~ 5 MPa and ~ 26 MPa at 1 year and 10 years of age, respectively, compared with those at 28 day of age. A comparison of the compressive strengths of concrete mixed with admixtures reported in the literature (based on age) and those obtained in this study showed that there was an initial strength difference in the range of 10–25%. However, the compressive strength at 10 years of age was almost similar to those reported in the literature with differences of less than 5%. These findings confirmed that when using pozzolanic admixtures, the development rate of the initial strength may vary owing to various factors; however, the long-term strength converges within a certain range.

Endo-β-1,3-glucanase is a glycoside hydrolase (GH) that plays an essential role in the mineralization of β-glucan polysaccharides. In this study, the novel gene encoding an extracellular, non-modular GH16 endo-β-1,3-glucanase (GluH) from Hymenobacter siberiensis PAMC 29290 isolated from Arctic marine sediment was discovered through an in silico analysis of its whole genome sequence and subsequently overexpressed in Escherichia coli BL21. The 870-bp GluH gene encoded a protein featuring a single catalytic GH16 domain that shared over 61% sequence identity with uncharacterized endo-β-1,3-glucanases from diverse Hymenobacter species, as recorded in the National Center for Biotechnology Information database. The purified recombinant endo-β-1,3-glucanase (rGluH: 31.0 kDa) demonstrated peak activity on laminarin at pH 5.5 and 40°C, maintaining over 40% of its maximum endo-β-1,3-glucanase activity even at 25°C. rGluH preferentially hydrolyzed D-laminarioligosaccharides and β-1,3-linked polysaccharides, but did not degrade D-laminaribiose or structurally unrelated substrates, confirming its specificity as a true endo-β-1,3-glucanase without ancillary GH activities. The biodegradability of various substrate polymers by the enzyme was evaluated in the following sequence: laminarin > barley β-glucan > carboxymethyl-curdlan > curdlan > pachyman. Notably, the specific activity (253.1 U mg–1) and catalytic efficiency (kcat/Km: 105.72 mg–1 s–1 mL) of rGluH for laminarin closely matched its specific activity (250.2 U mg–1) and kcat/Km value (104.88 mg–1 s–1 mL) toward barley β-glucan. However, the kcat/Km value (9.86 mg–1 s–1 mL) of rGluH for insoluble curdlan was only about 9.3% of the value for laminarin, which correlates well with the observation that rGluH displayed weak binding affinity (< 40%) to the insoluble polymer. The biocatalytic hydrolysis of D-laminarioligosaccharides with a degree of polymerization between 3 and 6 and laminarin generally resulted in the formation of D-laminaribiose as the predominant product and D-glucose as the secondary product, with a ratio of approximately 4:1. These findings suggest that highly active rGluH is an acidic, cold-adapted D-laminaribiose- and D-glucose-releasing GH16 endo-β-1,3-glucanase, which can be exploited as a valuable biocatalyst for facilitating low temperature preservation of foods. [ABSTRACT FROM AUTHOR]

Purpose To describe the optical coherence tomography features of pachyvitelliform maculopathy (PVM), an acquired vitelliform lesion (AVL) associated with pachychoroid disease. Methods This study was a retrospective, multicentre, observational analysis. Medical records and multimodal imaging were reviewed in all patients with pachychoroid disease and AVL. Visual acuity, central choroidal thickness (CCT), AVL dimensions, total choroidal area, luminal choroidal area, stromal choroidal area and choroidal vascular index were measured in all eyes with PVM and compared with normal age-matched control eyes. Results Mean age of the PVM group (17 eyes of 17 patients) was 71.41 years. Average follow-up was 33.15 months. Baseline VA was 20/40 in the PVM group and declined to 20/100 (p=0.006). AVLs were all detected overlying pachyvessels with optical coherence tomography and were all hyperautofluorescent with fundus autofluorescent imaging. Mean CCT in the PVM group was significantly greater (352.35 µm) than the CCT in the control group (226.88 µm, p<0.001). Retinal pigment epithelium (RPE) disruption was present in 64.71% of eyes with PVM at baseline and 41.18% developed macular atrophy at the end of follow-up. Conclusions PVM, defined by the presence of AVL associated with pachychoroid features, is a distinct novel entity of the pachychoroid disease spectrum. This study suggests a possible pathogenesis of RPE dysfunction secondary to a thick choroid, leading to accumulation of undigested photoreceptor outer segments and AVL. Clinicians should be aware of this common cause of vitelliform lesions and the poor visual prognosis due to the high risk of atrophy development. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the utilization of Al2O3 nanofluids in an Active Magnetic Regenerative (AMR) system, focusing on varying nanoparticle concentrations from 0.01 to 1.0%. Numerical modelling is used to analyze the effects of nanoparticle incorporation on system efficiency and cooling performance. Al2O3 nanoparticles are found to significantly increase the thermal conductivity, density, and viscosity of the base fluid while reducing specific heat capacity. Comparative analysis reveals that Al2O3 nanofluids outperform pure water in terms of cooling performance, achieving a lower final temperature and a higher temperature span after 60 min of operation. Moreover, the study highlights that cooling capacity and pumping work increase with higher nanoparticle concentrations, with a notable improvement of 64.95% in cooling capacity and 39.31% in pumping work for the 1.0% Al2O3 nanofluid compared to water. The Coefficient of Performance (COP) of the AMR system peaks at an optimal nanoparticle concentration of 0.2%, reaching 3.88, before declining due to increased pumping power requirements.

Abstract Hydrogen emerges as a promising alternative energy source, particularly in fuel cell applications, necessitating efficient and safe charging and storage systems. This paper presents the design and development of a specialized regulator tailored for high-pressure hydrogen environments. Focusing on precision control, the regulator ensures optimal performance and safety during charging and storage phases. In order to improve the unstable response characteristics of the existing commercial hydrogen regulator, which has the same differential pressure generation site and pressure control site, a regulator operating at an ultra-high pressure of 105 MPa was designed by separating the differential pressure site and the control site. And structural safety and performance of the regulator were predicted through structural and flow analysis. The results of structural and flow analysis of a 105 MPa high-pressure regulator that can be used for high-pressure hydrogen charging and storage systems were compared with the experimentally measured values.

Background and Objectives: This study aimed to investigate the association between insulin resistance, as measured by the triglyceride–glucose index (TyG index), and hearing impairment in middle-aged women in Korea. Materials and Methods: This cross-sectional survey utilized data from the Korea National Health and Nutrition Examination Survey (KNHANES) IV (2007–2009), specifically from the period after July 21, 2009, when hearing test results became available, and from the KNHANES V (2010–2012). This study was conducted on 5416 women aged 40 to 69 who had completed both the health examination survey and audiometric tests, excluding those with missing data on menopausal status and the use of hormone replacement therapy. Results: In the study group, the prevalence of high-frequency hearing loss according to the TyG index was significantly higher in the mild hearing loss group (OR = 1.29; 95% CI: 1.12, 1.49, p < 0.001) and the moderate hearing loss group (OR = 1.27; 95% CI: 1.09, 1.48, p = 0.002). Conversely, the prevalence of low-frequency hearing loss did not show a significant difference in either the mild hearing loss group (OR = 1.17; 95% CI: 0.99, 1.37, p = 0.065) and the moderate hearing loss group (OR = 1.13; 95% CI: 0.94, 1.35, p = 0.199) Conclusions: Since diabetes can induce hearing impairment in women, it is recommended that women with a high TyG index undergo early hearing tests

Prunus mume (maesil) is an economically important fruit in Korea. Recently, public interest in maesil sugar syrup is increasing. However, the presence of toxic amygdalin in the fruit syrup is a concern. Thus, the current investigation aimed to observe effects of maesil maturity, ripening methods, processing, and fermentation period on the amygdalin level in maesil sugar syrup. Six different types of maesil sugar syrup were prepared and amygdalin content was monitored at 3-month intervals. Higher levels (>63 mg/L) of amygdalin were found in syrups prepared from unripe fruit compared to those in syrups made from ripe fruit after 3 months of fermentation. A rapid reduction in amygdalin content was observed until 9 months in all syrups, gradually reducing to maesil sugar syrup, regardless of fruit maturity, source of fruit, and processing method.