• Ocean and Polar Research
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• v.44 no.4
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• pp.365-372
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• 2022

The present study measured the growth performance of juvenile hybrid of red-spotted grouper ♀ × giant grouper ♂ (RGGG) across four water temperatures (19, 23, 27, and 31℃) and compared it to those of maternal purebreds (red-spotted grouper ♀ × ♂, RG) for eight weeks. The specific growth rate (SGR) and weight gain (WG) of RGGG increased as temperature increased, with greater SGR and WG at higher temperatures (27 and 31℃) than RG. The condition factor of RGGG was higher than that of RG and there were no differences between temperature groups within breeding lines. Food consumption increased at higher temperatures for both RGGG and RG, and was the highest in the 31℃ group. Similar to the SGR and WG, the food conversion rate (FCR) in RGGG decreased with increasing water temperature, with the significantly lowest value at 31℃; in RG, however, FCR progressively decreased in the 27℃ group, then increased in the 31℃ group. Furthermore, the FCR of the 31℃ group of RGGG, which had the lowest value among the RGGG groups, was lower than that of the 27℃ group of RG, which had the lowest RG value. In the analysis of nonlinear regression curves within the range of experimental temperature, the optimum temperature for SGR and FCR in RGGG was 31℃, unlike in RG. In conclusion, the growth performance of juvenile RGGG seems to have largely improved from the influence of paternal traits, hybrid with giant grouper, and it is presumed to be more profitable for commercial production in tropics/subtropics.

• Molecules and Cells
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• v.45 no.8
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• pp.564-574
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• 2022

Epithin/PRSS14 is a membrane serine protease that plays a key role in tumor progression. The protease exists on the cell surface until its ectodomain shedding, which releases most of the extracellular domain. Previously, we showed that the remaining portion on the membrane undergoes intramembrane proteolysis, which results in the liberation of the intracellular domain and the intracellular domain-mediated gene expression. In this study, we investigated how the intramembrane proteolysis for the nuclear function is initiated. We observed that ectodomain shedding of epithin/PRSS14 in mouse breast cancer 4T1 cells increased depending on environmental conditions and was positively correlated with invasiveness of the cells and their proinvasive cytokine production. We identified selenite as an environmental factor that can induce ectodomain shedding of the protease and increase C-C motif chemokine ligand 2 (CCL2) secretion in an epithin/PRSS14-dependent manner. Additionally, by demonstrating that the expression of the intracellular domain of epithin/PRSS14 is sufficient to induce CCL2 secretion, we established that epithin/PRSS14-dependent shedding and its subsequent intramembrane proteolysis are responsible for the metastatic conversion of 4T1 cells under these conditions. Consequently, we propose that epithin/PRSS14 can act as an environment-sensing receptor that promotes cancer metastasis by liberating the intracellular domain bearing transcriptional activity under conditions promoting ectodomain shedding.

• Journal of Animal Science and Technology
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• v.64 no.2
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• pp.312-329
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• 2022

Feed cost is the main factor affecting the economic benefits of pig industry. Improving the feed efficiency (FE) can reduce the feed cost and improve the economic benefits of pig breeding enterprises. Liver is a complex metabolic organ which affects the distribution of nutrients and regulates the efficiency of energy conversion from nutrients to muscle or fat, thereby affecting feed efficiency. MicroRNAs (miRNAs) are small non-coding RNAs that can regulate feed efficiency through the modulation of gene expression at the post-transcriptional level. In this study, we analyzed miRNA profiling of liver tissues in High-FE and Low-FE pigs for the purpose of identifying key miRNAs related to feed efficiency. A total 212~221 annotated porcine miRNAs and 136~281 novel miRNAs were identified in the pig liver. Among them, 188 annotated miRNAs were co-expressed in High-FE and Low-FE pigs. The 14 miRNAs were significantly differentially expressed (DE) in the livers of high-FE pigs and low-FE pigs, of which 5 were downregulated and 9 were upregulated. Kyoto Encyclopedia of Genes and Genomes analysis of liver DE miRNAs in high-FE pigs and low-FE pigs indicated that the target genes of DE miRNAs were significantly enriched in insulin signaling pathway, Gonadotropin-releasing hormone signaling pathway, and mammalian target of rapamycin signaling pathway. To verify the reliability of sequencing results, 5 DE miRNAs were randomly selected for quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The qRT-PCR results of miRNAs were confirmed to be consistent with sequencing data. DE miRNA data indicated that liver-specific miRNAs synergistically acted with mRNAs to improve feed efficiency. The liver miRNAs expression analysis revealed the metabolic pathways by which the liver miRNAs regulate pig feed efficiency.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.617-624
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• 2023

Recently, miniaturization and low power consumption of electronic products and improved efficiency and power factor improvement have become a matter of great interest. In this paper, an AC-DC converter based on PWM control was designed and made. The AC-DC converter is designed with a structure in which one rectifier circuit and one output voltage control circuit are connected in series. The rectifier circuit is a diode-based single phase full-wave current circuit and the output voltage control circuit is a DC-DC conversion circuit based on PWM control. Arduino was used as the main control device for PWM control, and LCD was configured at the output stage so that the control result could be checked. The error between the output voltage displayed on the oscilloscope and LCD and the target output voltage was confirmed through repeated experiments with the test circuit, and the validity of the proposed design methodology was confirmed by showing an error rate of about 5% based on the oscilloscope measurement value.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.356-364
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• 2023

Sophisticated Air Navigation System has contributed to enhancing the capacity of airspace capacity, leading to an efficient airspace environment. However, it has acted as a factor increasing the probability of collision. When an aircraft fails to maintain vertical separation and instead exhibits lateral positional errors, it does not necessarily lead to a collision. However, as the lateral positional accuracy increases, the randomness of aircraft positions decrease, resulting in an elevated probability of collisions. Consequently, The International Civil Aviation Organization has introduced Strategic Lateral Offset Procedures(SLOP), intentionally deviating aircraft from the centerline of airways. Likewise, South Korea also operates Offset procedure. The Y579 was operated using the Offset before its conversion to a dual airway and the analysis of the Offset track revealed that it was being operated similarly to a unidirectional dual airway. This paper develops a safety assessment methodology applicable to unidirectional dual airways, and applies it to perform a safety assessment of the Y579 Offset procedure.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.168-174
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• 2023

In commercial production processes of methyl methacrylate, there is a methacryl aldehyde as an intermediate or impurities. The existence of impurities is critical factor because of significant decrease of the conversion rate and selectivity of the entire chemical reaction. This study found that an acid was the main cause of the decrease in reactivity among various impurities because an acid rapidly lowers the activity of a catalyst and promotes a side reaction, the hetero Diels-Alder reaction. Therefore, the pretreatment methods with the removal of acid were comparatively evaluated by the selective hydrogenation reaction of the carbonyl group of the reactants. Based on several experimental conditions, we believe that proposed effective pretreatment improves productivity with appropriate economical process.

• Elastomers and Composites
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• v.58 no.1
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• pp.32-43
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• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.

• Korea Trade Review
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• v.42 no.5
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• pp.1-18
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• 2017

This study focuses on the recent case held as to control in franchising. On the basis of analysis of the recent case, it examines the validity of the decision and suggests practical advice. The extensive judicial precedent has held that the franchisor and the franchisee possess the independent contractor relationship. But Williams v. Jani-king of Philadelphia Inc. suggest the conversion of the franchisee's status to an employees instead of an independent contractor. Franchisees allege that they were wrongly classified as independent contractors instead of employees because Jani-King had the ability to control the manner in which franchisees perform their day-to-day tasks. The appeal court held that Pennsylvania law does not distinguish between controls put in place to protect a franchise's intellectual property and controls for other purposes, and a franchisee may be an employee or an independent contractor depending on the nature of the franchise system controls. However, some degree of controls by the franchisor over the franchisee is inherent in the franchise and may even be mandated by the federal and state laws. Moreover, the appeal court affirmed that the franchise agreement, policies manual, and training manual alone could be sufficient to resolve the employment status. But it seems appropriate that the right to control on the documents is considered with the actual control.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.861-869
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• 2023

This study aimed to evaluate the effectivity of full-fat black soldier fly Hermetia illucens (BSF) and defatted mealworm Tenebrio molitor (MW) larvae meal as a fish meal (FM) substitute in a low-fish meal (LFM) diet for juvenile olive flounder Paralichthys olivaceus. The LFM diet comprising 45% FM with tankage meal, poultry byproduct meal, soy protein concentrate and wheat gluten was the control diet. Three experimental diets were 10% FM in Con with BSF, MW and a mixture of both at the same ratio (designated as B10, M10 and B5M5, respectively). Four hundred and forty-fourth juvenile P. olivaceus (34.3±0.1 g) were randomly distributed into 12 tanks (425 L) in three replicate groups per treatment and fed the experimental diets for 15 weeks. At the end of the feeding trial, growth performance, survival, biological indices (condition factor, viscerosomatic index, hepatosomatic index), non-specific immune responses (lysozyme, myeloperoxidase) and intestinal histology (villi length and goblet cells) were not significantly affected by treatments. Feed utilization was significantly decreased in M10 compared to the control group. Alanine aminotransferase level was significantly higher in M10 than in the control group. Glucose level was significantly lower in B10 than in the control group. These results suggest that BSF and MW can be used as FM substitutes. However, considering feed conversion ratio and AST level, MW availability is thought to be lower than that of BSF, and feeding fish with a diet containing MW for an extended period is thought to adversely affect fish growth.

• Journal of Electrochemical Science and Technology
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• v.15 no.1
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• pp.96-110
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• 2024

Polymer electrolyte membrane fuel cells (PEMFCs) are green energy conversion devices, for which commercial markets have been established, owing to their application in fuel cell vehicles (FCVs). Development of cathode electrocatalysts, replacing commercial Pt/C, plays a crucial role in factors such as cost reduction, high performance, and durability in FCVs. PtNi octahedral catalysts are promising for oxygen reduction reactions owing to their significantly higher mass activity (10-15 times) than that of Pt/C; however, their application in membrane electrode assemblies (MEAs) is challenged by their low stability. To overcome this durability issue, various approaches, such as third-metal doping, composition control, halide treatment, formation of a Pt layer, annealing treatment, and size control, have been explored and have shown promising improvements in stability in rotating disk electrode (RDE) testing. In this review, we aimed to compare the features of each strategy in terms of enhancing stability by introducing a stability improvement factor for a direct and reasonable comparison. The limitations of each strategy for enhancing stability of PtNi octahedral are also described. This review can serve as a valuable guide for the development of strategies to enhance the durability of octahedral PtNi.