• Clean Technology
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• v.30 no.2
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• pp.71-93
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• 2024

Recently, the establishment of a hydrogen-based economy and the utilization of low-carbon energy sources, particularly for shipping and power generation, have been in high demand in order to achieve carbon neutrality by 2050. In particular, ammonia is gaining renewed attention because it is capable of serving as a key facilitator for high-efficiency green hydrogen storage and transportation and it is also capable of serving as a low-carbon energy source. Although ammonia can be synthesized through the Haber-Bosch process, the high energy consumption and carbon emissions associated with this process result in minimal carbon reduction. To address the critical drawbacks of the traditional Haber-Bosch process, various thermochemical synthesis methods have been developed recently, allowing for the synthesis of ammonia with lower carbon emissions and a higher energy efficiency. Research is also progressing in the development of high-performance catalyst materials that are capable of demonstrating sufficient ammonia synthesis performance under milder process conditions compared to conventional methods. Additionally, a variety of different processes such as chemical-looping ammonia synthesis, plasma synthesis, and mechanochemical synthesis are being applied diversely. This review aims to provide a detailed overview of the emerging ammonia synthesis technologies that have been developed to effectively store green hydrogen for future applications.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.1-14
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• 2024

As awareness of environmental issues continues to grow, there is an escalating demand for recycling and repurposing byproducts of agricultural and food production processes and their conversion to high-value products. Coffee is the most widely consumed beverage globally; during coffee beverage processing and consumption, byproducts such as coffee silverskin (CS), spent coffee grounds (SCGs), and oil are generated. Despite containing beneficial materials such as cellulose, hemicellulose, lignin, lipids, and bioactive substances, these byproducts are typically discarded in landfills or incinerated. The utilization of CS, SCGs, and oil in the development of packaging materials holds significant potentials toward the realization of a sustainable society. To this end, considerable research efforts have been dedicated to the development of high-value materials derived from coffee byproducts, including functional fillers, polymer composites, and biodegradable polymers. Notably, CS and SCGs have been employed as functional fillers in polymer composites. Additionally, lipids extracted from SCGs have been used as plasticizers for polymers and cultured with microorganisms to produce biodegradable polymers. This review focuses on the research and development of polymer/CS and polymer/SCG composites as well as cellulose extraction and utilization from CS and SCGs and its applications, oil extraction from SCGs, and cultivation with microorganisms using extracted oil for polyhydroxyalkanoates(PHA) production.

• Journal of Life Science
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• v.34 no.1
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• pp.68-77
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• 2024

Airborne particulate matter (PM) is an environmentally hazardous pollutant that originates from various sources. PM is comprised of solid particles and liquid droplets of diverse composition and size. Hazardous chemical compositions of PM include elemental and organic carbon, organic compounds, biological compounds and metals. Upon acute and chronic PM exposure, toxic contaminants enter and accumulate within physiological systems and prompt cell structure changes accompanied with intracellular endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, inflammation, lipid accumulation, and cell cycle arrest. Ultimately, these cellular response leads to the development of key characteristics of aging. In addition, PM internalization enhances autophagy reflux and lysosomal dysfunction, which is involved in cell aging. Previous studies have emphasized a positive association between PM and increased mortality or decreased lifespan, although these are evidenced mostly by observational studies. Direct evidence of the link between PM and aging is still limited. This review evaluates the evidence from not only observational studies but also in vitro and in vivo evidence of PM on aging progression and age-related diseases development. This evidence is based on age-associated cellular changes including endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, inflammation, adipose accumulation, autophagy, which strengthen the association between PM exposure and aging. Understanding the underlying cellular responses under PM may allow for the development of new therapeutic targets for PM-induced aging.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.67-78
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• 2024

Light absorption has potential as a signal in biochemical analyses due to its simplicity in measurement and interpretational clarity. Among substances that generate absorption signals, gold nanoparticles possess advantages such as chemical stability, biological compatibility, and unique optical properties from the localized surface plasmon resonance (LSPR) in the visible light range. They also exhibit versatility compared to other colorimetric substances effective only for specific target molecules, as they easily conjugate with various detection active substances like antibodies and aptamers. Particularly due to advantages such as low cost, ease of particle synthesis, and high environmental stability compared to enzyme-based colorimetric methods, gold nanoparticles are extensively researched as signal substances in colorimetric assays. This review summarizes various strategies utilizing gold nanoparticles as absorption signal substances, focusing on recent research. Based on the characteristics of gold nanoparticles, where the optical property is influenced by particle morphology, literature is classified and reviewed based on strategies controlling the shape of gold nanoparticles during signal generation. Through this, it is observed that gold nanoparticles, which have been used as absorption signal substances, continue to be actively researched, affirming their potential for broad and continuous improvement in the future.

• Journal of Life Science
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• v.34 no.8
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• pp.594-607
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• 2024

Plastic products have long been widely used in both industrial and household applications. However, tiny plastic particles derived from plastic products, such as microplastics (MPs) and nanoplastics (NPs), can infiltrate the human body through inhalation, ingestion, or skin contact. Once inside cells via endocytosis, MPs and NPs (MNPs) can trigger autophagy, but lysosomal dysfunction can block autophagic flux. Accumulating in the cytoplasm, these particles induce cellular stress, including oxidative stress from free radicals, mitochondrial dysfunction, and increased inflammatory response. Meanwhile, cellular senescence is a hallmark of aging and is defined as the stable termination of the cell cycle in response to cell damage and stress. In particular, the accumulation of oxidative stress, a key factor in inducing cellular senescence, induces the expression of major senescence markers. Senescent cells increase the secretion of senescence-associated secretory phenotype, including inflammatory cytokines and chemokines. Despite growing interest in how MNPs induce cellular senescence, there remains a gap regarding their onset and therapeutic targets. Therefore, this review focuses on identifying recent research trends on how MNPs induce cellular aging in key human cell types and proposes future research directions to overcome these challenges.

• Clean Technology
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• v.30 no.3
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• pp.175-187
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• 2024

Seaweeds are widely distributed along national coastlines around the world, and the biomass derived from them is an important marine biological organism. Seaweed is a crucial component of a healthy marine ecosystem. However, changes in marine environments have led to the occurrence of urchin barrens, and the damage caused by this phenomenon is steadily increasing. As a result, investigations into the distribution and spread of urchin barrens in the coastal areas of South Korea are being conducted regularly so efficient detection technologies are essential. One of the technologies that can swiftly and accurately analyze extensive areas is detection technology based on hyperspectral image information systems. This study aims to present the latest hyperspectral imaging technology for investigating the current status of urchin barrens and the methods for classifying this technology, including principles, preprocessing techniques, and correction methods. This study also proposes a classification technique for urchin barrens along the coast of Jeju Island that uses hyperspectral images and categorizes the urchin barrens into initial, intermediate, and advanced stages. The results showed that approximately 17.5% of the experimental areas were in the advanced stage. Based on this, various management and restoration methods tailored to different categories of urchin barren can be proposed.

• Applied Chemistry for Engineering
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• v.35 no.5
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• pp.372-378
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• 2024

MXene, a two-dimensional transition metal carbide, nitride, or carbonitride, possesses exceptionally thin and large surface areas while also exhibiting remarkable electrical and chemical properties. These properties have attracted considerable interest in the application of MXene, including energy storage devices, sensors, and catalysts. Since the discovery of MXene in 2011, a number of synthetic methods have been proposed. The synthesis of MXene can be mainly divided into two stages: an etching step and a delamination step. The type of terminations or surface defects are dependent on the synthetic method and have a significant impact on key properties such as electrical conductivity. Therefore, research on synthetic methods is essential for the industrialization of MXene. This review provides an overview of the various etching methods and delamination strategies employed in the synthesis of Ti₃C₂T_x MXene, including the commonly used hydrofluoric acid etching method and the fluorine-free method, which has recently emerged as an environmentally friendly alternative. We also address the latest research trends, challenges, and perspectives for the industrialization of MXene.trialization of MXene.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.5-17
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• 2018

The standardized eddy covariance flux data processing in KoFlux has been updated, and its database has been amended accordingly. KoFlux data users have not been informed properly regarding these changes and the likely impacts on their analyses. In this paper, we have documented how the current structure of data processing in KoFlux has been established through the changes and improvements to ensure transparency, reliability and usability of the KoFlux database. Due to increasing diversity and complexity of flux site instrumentation and organization, we have re-implemented the previously ignored or simplified procedures in data processing (e.g., frequency response correction, stationarity test), and added new methods for $CH_4$ flux gap-filling and $CO_2$ flux correction and partitioning. To evaluate the effects of the changes, we processed the data measured at a flat and homogeneous paddy field (i.e., HPK) and a deciduous forest in complex and heterogeneous topography (i.e., GDK), and quantified the differences. Based on the results from our overall assessment, it is confirmed that (1) the frequency response correction (HPK: 11~18% of biases for annually integrated values, GDK: 6~10%) and the stationarity test (HPK: 4~19% of biases for annually integrated values, GDK: 9~23%) are important for quality control and (2) the minimization of the missing data and the choice of the appropriate driver (rather than the choice of the gap-filling method) are important to reduce the uncertainty in gap-filled fluxes. These results suggest the future directions for the data processing technology development to ensure the continuity of the long-term KoFlux database.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.65-70
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• 2010

Medium-chain fatty acids (MCFA) are composed of 8-12 carbon atoms, and are found in coconut, cuphea, and palm kernel oil. MCFA were introduced into clinical nutrition in the 1950s for dietary treatment of malabsorption syndromes because of their rapid absorption and solubility. Recently, MCFA have been applied to Gastrointestinal Permeation Enhancement Technology (GIPET), which is one of the most important parts in drug delivery system in therapeutics. Therefore, to accumulate the MCFA in seed oil of rapeseed, much effort has been conducted by classical or molecular breeding. Laurate can be successfully accumulated up to 60 mol% in the seed oil of rapeseed by the expression of bay thioesterase (Uc FatB1) alone or crossed with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT) under the control of a napin seed-storage protein promoter. Also, caprylate and caprate were obtained 7 mol% and 29 mol%, respectively, from plants over-expressing of the medium-chain specific thioesterase (Ch FatB2) alone or together with the chain-length-specific condensing enzyme (Ch KASIV). Despite the success of some research in utilizing parallel classical and molecular breeding to produce MCFA, commercially available seed oils have for the most part, not been realized. Recent research in the field of developing MCFA-enriched transgenic plants has established that there is no single rate-limiting step in the production of the target fatty acids. The purpose of this article is to review some of the recent progress in understanding the mechanism and regulation of MCFA production in seed oil of rapeseed.

• Journal of Dairy Science and Biotechnology
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• v.32 no.1
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• pp.17-29
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• 2014

GRAS probiotics can be used to modulate intestinal microbiota and to alleviate various gastrointestinal disorders. In several recent studies, researchers have explored the potential expansion and usability of probiotics to reduce the risk factors associated with diseases, including obesity, hypercholesterolemia, arterial hypertension, hyperhomocysteinemia, and oxidative stress. In this review, our aim was to clarify the mechanism underlying interactions between hosts (animal or human) and probiotics and the beneficial effects of probiotics on human health.