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This paper compares the axial shortening behaviors of reinforced concrete (RC) and concrete-filled tube (CFT) columns in high-rise building structures and proposes a relationship between the differential axial shortening and the dead load portion. This relationship can be used to determine the initial column sections in the preliminary design of building structures. Factors that can influence the differential axial shortening in columns were considered, and numerical analyses were conducted to compare the relative effectiveness of CFT columns. The time-dependent deformation of concrete was found to be the most significant influencing factor when compared with the flattening process of each floor level and construction sequence analysis. However, parametric studies demonstrate that axial shortening behavior can be ignored in buildings of fewer than 20 floors, and that it has a negligible effect even in taller buildings. Notably, the differential axial shortening effect can be excluded in the preliminary design stage when the dead load portion is less than 30% of the ultimate axial resistance. In the absence of design standards recommendations for reference values to minimize serviceability or damage problems in building structures, the proposed relation between the differential axial shortening and the dead load portion can be effectively used to determine initial column sections in the preliminary design of building structures.

Fishing is considered one of the most dangerous industries alongside mining that needs further efforts to improve safety. In this study, we have investigated safety management of the gillnet fishing industry in South Korea through identifying safety level and classifying common accident types from the statements of accident com-pensation insurance payments for the last 5 years (2016-2020). There were in total 3,895 accidents and 159 fatalities with an average accident frequency of 5.34 × 10−2 per year per fisher and an average fatality of 2.18 × 10−3 fishers per year. We have also identified that 62.4% of the accidents occurred during Fishing (FS), and the most common and the most severe accident type is Slips and Trips (ST) and Other (OT) marine accidents such as collision and capsizing, respectively. The hand was most frequently injured. Finally, the risk assessment indicated that most of the accident types of gillnet fishing in South Korea have unacceptable levels of risks, and it is urgent to implement improved safety measures to reduce accidents during gillnet fishing operation. The findings of this study are expected to provide valuable data to create a safer working environment for fishers working on gillnet fishing vessels.

The gastrointestinal microbiota are important for human health. Dietary intake may modulate the composition and metabolic function of the gut microbiome. We examined how the breakdown of prebiotic dietary fibers by the gut microbiome affects mucin secretion by intestinal epithelial cells. Metagenomic analyses of in vitro gut microbiome consortia revealed taxonomic profiles and genetic diversity of carbohydrate-active enzymes that digest polysaccharides. Two independent consortia exhibited different abilities to produce acetic acid, propionic acid, and butyric acid via the fermentation of polysaccharides derived from dietary fibers of grains and mushrooms. Although acetic acid generally had the highest concentration, the ratios of butyric acid and propionic acid to acetic acid varied depending on the polysaccharide source. These short-chain fatty acids affected morphological differentiation and mucin secretion in HT-29 human intestinal epithelial cells. These results suggest that prebiotic dietary fibers can be digested and metabolized by the gut microbiome to short-chain fatty acids, which can affect gut epithelial cells both directly and indirectly via the modulation of the gut microbiota and their enzymes.

Given the importance of digital technology in daily life, computational thinking (CT) has become a necessary skill for everyone, not just for computer scientists. For CT development, students need to receive appropriate social learning support. However, instructors find it difficult to provide such support to many students in online courses. This study aimed to examine the effectiveness of e-mentoring via social network services (SNS) in developing students’ CT during large-scale online courses. A total of 327 undergraduate students volunteered to participate in this study, which included 16 weeks of lectures aimed at developing CT. The effects of SNS-based e-mentoring on CT development, the influences of each e-mentoring activity on CT development, and gender differences were analyzed using data on participants’ CT assistance scores and their utilization of e-mentoring activities. The findings indicated that SNS-based e-mentoring was effective in developing the CT of undergraduate students’ engagement in a large-scale online course. The most influential e-mentoring activities for students’ CT development were informational and technical support in a group and informational support in a private environment. Female students benefited more from SNS-based e-mentoring than male students, and they also engaged in more types of e-mentoring activities than male students. Participation in SNS-based e-mentoring was found to lower the gap in CT between students with and without prior learning experience. Our study findings can be used by educational institutions and instructors when designing courses for students’ CT development in large-scale online courses or when developing strategies to close the gender gap in CT ability.

BackgroundApproximately 30% of diabetic patients develop diabetic nephropathy, a representative microvascular complication. Although the etiological mechanism has not yet been fully elucidated, renal tubular damage by hyperglycemia-induced expression of transforming growth factor-β (TGF-β) is known to be involved. Recently, a new type of cell death by iron metabolism called ferroptosis was reported to be involved in kidney damage in animal models of diabetic nephropathy, which could be induced by TGF-β. Bone morphogenetic protein-7 (BMP7) is a well-known antagonist of TGF-β inhibiting TGF-β-induced fibrosis in many organs. Further, BMP7 has been reported to play a role in the regeneration of pancreatic beta cells in diabetic animal models.MethodsWe used protein transduction domain (PTD)-fused BMP7 in micelles (mPTD-BMP7) for long-lasting in vivo effects and effective in vitro transduction and secretion.ResultsmPTD-BMP7 successfully accelerated the regeneration of diabetic pancreas and impeded progression to diabetic nephropathy. With the administration of mPTD-BMP7, clinical parameters and representative markers of pancreatic damage were alleviated in a mouse model of streptozotocin-induced diabetes. It not only inhibited the downstream genes of TGF-β but also attenuated ferroptosis in the kidney of the diabetic mouse and TGF-β-stimulated rat kidney tubular cells.ConclusionBMP7 impedes the progression of diabetic nephropathy by inhibiting the canonical TGF-β pathway, attenuating ferroptosis, and helping regenerate diabetic pancreas.

In this study, experimental fishing trials were performed to quantitatively evaluate and compare the fishing performance of trammel nets, tie-down gillnets, and single gillnets used for catching blackfin flounder. A total of eight cruises performed at depths of 100–140 m in the waters near Yangyang, Gangwon-do, Korea. Fisheries laws in Korea currently restrict the use of trammel nets due to concerns about overfishing and bycatch. Tie-down gillnets have a support line that changes their stretched height, thus increasing their catch rate, and are an attractive alternative to trammel nets or single gillnets; unmodified gillnet. Due to a lack of quantitative evaluation of their fishing performance, the performances of these three types of gillnets quantitatively compared. The number and weight of fish, particularly blackfish flounder, caught by each net under similar circumstances were compared. Our results suggest that the fishing performance of trammel nets and tie-down gillnets is much higher than that of single gillnets. Compared to single gillnets, trammel nets performed better by 2.98 times and 2.45 times, in terms of the total number and weight of fish caught, respectively, and tie-down gillnets performed better by 2.09 times and 1.97 times, respectively. In addition, the bycatch rate of tie-down gillnet for immature blackfin flounder with the total length less than 20 centimeters was similar to single gillnet; single gillnet 17.5% of immature blackfin flounder, tie-down 20% of immature blackfin flounder, trammel net 62.5% of immature blackfin flounder. Given that many flat fish such as flounders fall out of the net during the fishing process after being stuck in single gillnets, fishermen hope to use trammel nets. However, the relatively high catch rate of trammel nets likely necessitates restrictions for their use. This study suggests that tie-down gillnets are an option for sustainable fishing practice given that they perform better than single gillnet and reduce bycatch of immature blackfin flounder when compared to trammel nets.

Abstract The NLRP3 inflammasome is activated by mitochondrial damage and contributes to kidney fibrosis. However, it is unknown whether PGC-1α, a key mitochondrial biogenesis regulator, modulates NLRP3 inflammasome in kidney injury. Primary renal tubular epithelial cells (RTECs) were isolated from C57BL/6 mice. The NLRP3 inflammasome, mitochondrial dynamics and morphology, oxidative stress, and cell injury markers were examined in RTECs treated by TGF-β1 with or without Ppargc1a plasmid, PGC-1α activator (metformin), and siPGC-1α. In vivo, adenine-fed and unilateral ureteral obstruction (UUO) mice were treated with metformin. In vitro, TGF-β1 treatment to RTECs suppressed the expressions of PGC-1α and mitochondrial dynamic-related genes. The NLRP3 inflammasome was also activated and the expression of fibrotic and cell injury markers was increased. PGC-1α induction with the plasmid and metformin improved mitochondrial dynamics and morphology and attenuated the NLRP3 inflammasome and cell injury. The opposite changes were observed by siPGC-1α. The oxidative stress levels, which are inducers of the NLRP3 inflammasome, were increased and the expression of TNFAIP3, a negative regulator of NLRP3 inflammasome regulated by PGC-1α, was decreased by TGF-β1 and siPGC-1α. However, PGC-1α restoration reversed these alterations. In vivo, adenine-fed and UUO mice models showed suppression of PGC-1α and TNFAIP3 and dysregulated mitochondrial dynamics. Moreover, the activation of oxidative stress and NLRP3 inflammasome, and kidney fibrosis were increased in these mice. However, these changes were significantly reversed by metformin. This study demonstrated that kidney injury was ameliorated by PGC-1α-induced inactivation of the NLRP3 inflammasome via modulation of mitochondrial viability and dynamics.

The small intestine is a digestive organ that has a complex and dynamic ecosystem, which is vulnerable to the risk of pathogen infections and disorders or imbalances. Many studies have focused attention on intestinal mechanisms, such as host–microbiome interactions and pathways, which are associated with its healthy and diseased conditions. This review highlights the intestine models currently used for simulating such normal and diseased states. We introduce the typical models used to simulate the intestine along with its cell composition, structure, cellular functions, and external environment and review the current state of the art for in vitro cell-based models of the small intestine system to replace animal models, including ex vivo, 2D culture, organoid, lab-on-a-chip, and 3D culture models. These models are described in terms of their structure, composition, and co-culture availability with microbiomes. Furthermore, we discuss the potential application for the aforementioned techniques to these in vitro models. The review concludes with a summary of intestine models from the viewpoint of current techniques as well as their main features, highlighting potential future developments and applications.

Many studies have been conducted with the aim of reducing fuel consumption by the fishing industry. We examined whether drag can be reduced by changing the arrangement of gears without requiring the development of new parts for the conventional float and ground gear. Ten differently shaped floats and ground gears were measured in a water flume tank. The float and ground gear were fixed to a steel rod to measure fluid drag according to attack angle, using a multi-component load cell. To estimate the frictional drag of ground gear on the seabed, five types of large ground gear were towed on flat land while changing attack angle using the load cell to measure tension. The fluid drag of the float and ground gear was highest at an attack angle of 60°, regardless of shape, size, and flow velocity. The resistance coefficients of the float and ground gear varied depending on the attack angle and tended to be lower at small attack angles. The frictional drag of the ground gear was greater when the axis of rotation had a small attack angle in the towing direction compared to other attack angles. We then investigated a method for designing bottom-towed gear that reduces drag while maintaining the size, buoyancy, and sinking force of conventional fishing gear parts. This gear design showed 1.2% drag reduction and an estimated 0.8% improvement in fuel efficiency per haul.

The bluefin sea robin (Chelidonichthys spinosus), hereafter BSR, is one of the most important fish species in the South Sea of Korea. The production value of BSR in 2020 was USD 4,733,057. The production volume in Korea has shown an annual mean increase of 8.9% since 2010, but the efficiency of the fishing gear decreased due to excessive use. This has led to a decrease in the profitability of fishery operators, and as compensation, the use of fishing gear has further increased through competitive operations. Alternative measures for improving catch performance and reducing the use of fishing gear are needed. As one such measure, LED (Light-Emitting Diode) lights were attached to the pot, and the effects were determined. The field experiment results showed that the catch of BSR was higher for the experimental groups (n = 10–273) using fishing gear with LED lights (red, green, blue, and white) than for the control group (n = 2) (Kruskal–Wallis test, p < 0.05). Among the experimental groups, the pot with green light achieved the largest catch (n = 273). The use of LED lights was found to enhance the catch efficiency of pot fishing gear for BSR.