• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.108-113
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• 2022

Arsenic (As) uptake and accumulation from agricultural soil to rice vary depending on the soil environmental conditions such as soil pH, redox potential, clay content, and organic matter (OM) content. Therefore, these factors are important in predicting changes in the uptake and accumulation of As in rice plants. Here, we studied the chemical properties of As-contaminated and/or rice straw compost (RSC)-treated soils, the growth responses of RSC-applied rice plants under As-contaminated soils, the changes in As content of soil, and the relationship between As uptake and accumulation from the RSC-treated soils to the rice organs under As-contaminated soils. Rice plants were cultivated in 30 mg kg^-1 As-contaminated soils under three RSC treatments: 0 (control), 12, and 24 Mg ha^-1. No significant differences were indicated in the chemical properties of pre-experimental (before transplanting rice seedling) soils, with the exception of EC, OM, and available P₂O₅. As the treatment of RSC under 30 mg kg^-1 As-contaminated soils increased, EC, OM, and available P₂O₅ increased proportionally in soil. Increased soil RSC under As-contaminated soils increased shoot dry weight of rice plants at harvesting stage. As content in roots increased proportionally with RSC content, whereas As content in shoots decreased under As-contaminated soil at all stages of rice plants. Nevertheless, As accumulation were significantly decreased in both roots and shoots of RSC-treated rice plants than those in the plants treated without RSC. These results indicate that the use of RSC can mitigate As phytotoxicity and reduce As accumulation in rice plants under As-contaminated soils. Therefore, RSC can potentially be applied to As-contaminated soil for safe crop and forage rice production.

• Journal of Life Science
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• v.32 no.1
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• pp.63-69
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• 2022

The thioredoxin reductase (TrxR) system is essential for cell survival and function by playing a pivotal role in maintaining homeostasis of cellular redox and regulating signal transduction pathways. The TrxR system comprises thioredoxin (Trx), TrxR, and nicotinamide adenine dinucleotide phosphate. Trx reduced by the catalytic reaction of the TrxR enzyme reduces downstream proteins, resulting in protection against oxidative stress and regulation of cell differentiation, growth, and death. Cancer cells survive by improving their intracellular antioxidant capacity to eliminate excessively generated reactive oxygen species (ROS) due to infinite cell proliferation and a high metabolic rate. Therefore, cancer cells have high dependence and sensitivity to antioxidant systems, suggesting that focusing on TrxR, a representative antioxidant system, is a potential strategy for cancer therapy. Several studies have revealed that TrxR is expressed at high levels in various types of cancers, and research on anticancer activity targeting the TrxR system is increasing. In this review, we discuss the feasibility and value of the TrxR system as a strategy for anticancer activity research by examining the relationship between the function of the intracellular TrxR system and the development and progression of cancer, considering the anticancer activity and mechanism of TrxR inhibitors.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.574-581
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• 2022

Nanofibers comprising reduced graphene oxide (rGO) and Mo₂C/Mo₂N nanoparticles (Mo₂C/Mo₂N rGO NFs) were prepared for a functional interlayer of Li-S batteries (LSBs). The well-dispersed Mo₂C and Mo₂N nanoparticles in the nanofiber structure served as active polar sites for efficient immobilization of dissolved lithium polysulfide. The rGO nanosheets in the structure also provide conductive channels for fast ion/electron transport during charging-discharging and ensured reuse of lithium polysulfide during redox reactions through a fast charge transfer process. As a result, the cell assembled with Mo₂C/Mo₂N rGO NFs-coated separator and pure sulfur electrode (70 wt% of sulfur content and 2.1 mg cm^-2 of sulfur loading) showed a stable discharge capacity of 476 mA h g^-1 after 400 charge-discharge cycles at 0.1 C. Furthermore, it exhibited a discharge capacity of 574 mA h g^-1 even at a high current density of 1.0 C. Therefore, we believe that the proposed unique nanostructure synthesis strategy could provide new insights into the development of sustainable and highly conductive polar materials as functional interlayers for high performance LSBs.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.188-194
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• 2022

This work presents a non-destructive and straightforward approach to assemble a large-scale conductive electronic film made of a pre-treated single-walled carbon nanotube (SWCNT) solution. For effective electron transfer between the immobilized enzyme and SWCNT electronic film, we optimized the pre-treatment step of SWCNT with p-terphenyl-4,4"-dithiol and dithiothreitol. Glucose oxidase (GOx, a model enzyme in this study) was immobilized on the SWCNT electronic film following the positively charged polyelectrolyte layer deposition. The glucose detection was realized through effective electron transfer between the immobilized GOx and SWCNT electronic film at the negative potential value (-0.45 V vs. Ag/AgCl). The SWCNT electronic film-based glucose biosensor exhibited a sensitivity of 98 ㎂/mM·cm². In addition, the SWCNT electronic film biosensor showed the excellent selectivity (less than 4 % change) against a variety of redox-active interfering substances, such as ascorbic acid, uric acid, dopamine, and acetaminophen, by avoiding co-oxidation of the interfering substances at the negative potential value.

• Membrane Journal
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• v.33 no.4
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• pp.211-221
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• 2023

This study presents a comprehensive study on the synthesis and characterization of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C flexible electrodes for energy storage applications. The dual-functional PVI-PGMA copolymer exhibited excellent ionic conductivity, with the PVI-PGMA73/LiTFSI200 membrane electrolyte achieving the highest conductivity of 1.0 × 10^-3 S cm^-1. The electrochemical performance of the CxNy-C electrodes was systematically investigated, with C3N2-C demonstrating superior performance, achieving the highest specific capacitance of 958 F g^-1 and lowest charge transfer resistance (R_ct) due to its highly interconnected hybrid structure comprising nanowires and polyhedrons, along with binary Co/Ni oxides, which provided abundant redox-active sites and facilitated ion diffusion. The presence of a graphitic carbon shell further contributed to the enhanced electrochemical stability during charge-discharge cycles. These results highlight the potential of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C electrodes for advanced energy storage devices, such as supercapacitors and lithium-ion batteries, paving the way for further advancements in sustainable and high-performance energy storage technologies.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.3
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• pp.95-120
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• 2023

Methane (CH₄) is a key greenhouse gas in the atmosphere with 85 times greater greenhouse potent relative to carbon dioxide (CO₂). The atmospheric concentration of CH₄ is rapidly increasing due to the intensive usage of CH₄ and the thawing of the cryosphere. Additionally, with the current warming of ocean water, the dissociation of gas hydrates, an ice-like compound and the largest reservoir of CH₄ on Earth, is expected to occur, resulting in the release of CH₄ from the seafloor into the overlying water and atmosphere. Moreover, bottom water hypoxia is another concern that potentially introduces greenhouse gases into the atmosphere. With ongoing global warming and eutrophication, the size and duration of bottom water hypoxia are rapidly increasing. These low-oxygen conditions would relocate the redox zone shallower in sediment or in the water column, causing the release of CH₄ into the atmosphere and thereby intensifying global warming. However, there exists a gap in the understanding of CH₄ dynamics including its generation in relation to bottom water hypoxia. Therefore, this review article aims to understand the relationship between CH₄ and bottom water hypoxia and to draw attention to CH₄ investigation in Korea.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.43-53
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• 2023

This batch experiment evaluated the impacts of major plant nutrient releases by applying the modified Hyperbola model on the leachates and N₂O emissions from incorporated rice hull biochar with organic fertilizer materials. The treatments consisted of the control as incorporated with organic fertilizer materials, the incorporated rice hull biochar with organic fertilizer materials, and the incorporated plasma-activated rice hull biochar with organic fertilizer materials under redox conditions. The results indicated that the maximum release amount of NH₄-N was 3486.3 mg L^-1 in the control, and their reduction rates of NH₄-N, NO₃-N, PO₄-P, and K were 8.0%, 17.5% 44.3.0% and 8.7%, respectively, relative to the control. In the control, the highest soluble amount of PO₄-P was 681.0 mg L^-1. The estimations for accumulated NH₄-N, NO₃-N, PO₄-P, and K-releases in all the treatments were significantly (p<0.01) fitted with a modified Hyperbola model. For greenhouse gas emissions, the lowest cumulative N₂O was 340.4 mg kg^-1 in the soil incorporated with plasma-activated rice hull biochar, and the reduction rates were 27.8% and 86.4% in the rice hull biochar and plasma-activated rice hull biochar treatments, respectively, compared to the control. Therefore, it concluded that the incorporated rice hull biochar can be especially useful for controlling PO₄-P release and N₂O emissions for bio-fertilizer applications.

• Clean Technology
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• v.16 no.2
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• pp.132-139
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• 2010

The Cu-Mn mixed oxide catalysts with different molar ratios of Cu/(Cu+Mn) prepared by co-precipitation method have been investigated in CO oxidation at $30^{\circ}C$. The catalysts used in this study were characterized by X-ray Diffraction (XRD), $N_2$ sorption, X-ray photoelectron spectroscopy (XPS), and $H_2$-temperature programmed reduction $(H_2-TPR)$ to correlate with catalytic activities in CO oxidation. The $N_2$ adsorption-desorption isotherms of Cu-Mn mixed oxide catalysts showed a type 4 having pore range of 7-20 nm and BET surface area was increased from 17 to $205\;m^2{\cdot}g^{-1}$ with increasing of Mn content. The XPS analysis showed the surface oxidation state of Cu and Mn represented $Cu^{2+}$and the mixture of $Mn^{3+}$ and $Mn^{4+}$, respectively. Among the catalysts studied here, Cu/(Cu+Mn) = 0.5 catalyst showed the highest activity at $30^{\circ}C$ in CO oxidation and the catalytic activity showed a typical volcano-shape curve with respect to Cu/(Cu+Mn) molar ratios. The water vapor showed a prohibiting effect on the efficiency of the catalyst which is due to the competitive adsorption of carbon monoxide on the active sites of catalyst surface and finally the formation of hydroxyl group with active metals.

• Nutrition Research and Practice
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• v.17 no.2
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• pp.228-240
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• 2023

BACKGROUND/OBJECTIVES: Cocoa consumption is associated with health benefits due to its high content of polyphenols. However, the effects of short-term cocoa consumption remain unclear. We aimed to determine the effects generated by cocoa consumption (for 7 days) in young adults in normoweight and class II obesity. SUBJECTS/METHODS: Before-and-after study was carried out in normoweight (NW) (n = 15) and class II obesity (CIIO) (n = 15) young adults. The NW and CIIO participants consumed 25 and 39 g of cocoa, respectively, per day for 7 days. The effect of cocoa consumption was evaluated on the lipid profile, insulin resistance (IR), and inflammation. Oxidative damage was also examined by assessing the biomarkers of oxidative damage in plasma. In addition, recombinant human insulin was incubated with blood obtained from the participants, and the molecular damage to the hormone was analyzed. RESULTS: Cocoa consumption resulted in decreased low-density lipoprotein-cholesterol in both groups (P = 0.04), while the total cholesterol, high-density lipoprotein cholesterol, and triglycerides were maintained at the recommended levels. Initially, IR was detected in the CIIO group (homeostasis model assessment [HOMA] = 4.78 ± 0.4), which is associated with molecular damage to insulin. Interestingly, intervention with cocoa resulted in improved IR (HOMA = 3.14 ± 0.31) (P = 0.0018) as well as molecular damage to insulin. Finally, cocoa consumption significant decreased the arginase activity (P = 0.0249) in the CIIO group; this is a critical enzymatic activity in the inflammatory process associated with obesity. CONCLUSIONS: The short-term consumption of cocoa improves the lipid profile, exerts anti-inflammatory effects, and protects against oxidative damage. Results of this study indicate that cocoa consumption can potentially improve IR and restore a healthy redox status.

• Animal Bioscience
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• v.36 no.7
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• pp.1022-1033
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• 2023

Objective: p66Shc, a 66 kDa protein isoform encoded by the proto-oncogene SHC, is an essential intracellular redox homeostasis regulatory enzyme that is involved in the regulation of cellular oxidative stress, apoptosis induction and the occurrence of multiple age-related diseases. This study investigated the expression profile and functional characteristics of p66Shc during preimplantation embryo development in sheep. Methods: The expression pattern of p66Shc during preimplantation embryo development in sheep at the mRNA and protein levels were studied by quantitative real-time polymerase chain reaction (RT-qPCR) and immunofluorescence staining. The effect of p66Shc knockdown on the developmental potential were evaluated by cleavage rate, morula rate and blastocyst rate. The effect of p66Shc deficiency on reactive oxygen species (ROS) production, DNA oxidative damage and the expression of antioxidant enzymes (e.g., catalase and manganese superoxide dismutase [MnSOD]) were also investigated by immunofluorescence staining. Results: Our results showed that p66Shc mRNA and protein were expressed in all stages of sheep early embryos and that p66Shc mRNA was significantly downregulated in the 4-to 8-cell stage (p<0.05) and significantly upregulated in the morula and blastocyst stages after embryonic genome activation (EGA) (p<0.05). Immunofluorescence staining showed that the p66Shc protein was mainly located in the peripheral region of the blastomere cytoplasm at different stages of preimplantation embryonic development. Notably, serine (Ser36)-phosphorylated p66Shc localized only in the cytoplasm during the 2- to 8-cell stage prior to EGA, while phosphorylated (Ser36) p66Shc localized not only in the cytoplasm but also predominantly in the nucleus after EGA. RNAi-mediated silencing of p66Shc via microinjection of p66Shc siRNA into sheep zygotes resulted in significant decreases in p66Shc mRNA and protein levels (p<0.05). Knockdown of p66Shc resulted in significant declines in the levels of intracellular ROS (p<0.05) and the DNA damage marker 8-hydroxy2'-deoxyguanosine (p<0.05), markedly increased MnSOD levels (p<0.05) and resulted in a tendency to develop to the morula stage. Conclusion: These results indicate that p66Shc is involved in the metabolic regulation of ROS production and DNA oxidative damage during sheep early embryonic development.