• Clean Technology
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• v.28 no.2
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• pp.163-173
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• 2022

Research and development of biofuels as one of the means to mitigate global warming and to avoid fossil fuel depletion has occurred for more than 30 years. However, there has only been limited distribution of a few first- and second-generation biofuels, and widespread supply and consumption of biofuels is still far from a reality. Although a relatively recently studied third-generation biofuel derived from seaweed biomass has been shown to have many advantages, it is yet to be deployed in commercial-scale seaweed biorefineries. This review paper examines the advantages and disadvantages of seaweed biorefineries for the entire value chain covering from seaweed and its cultivation to biofuel production based on an extensive literature search and the author's experience of conducting feasibility studies pertaining to seaweed biorefineries for over 10 years. For this purpose, the literature survey will cover the current status of seaweed production and its research and development worldwide, conversion technologies for biofuel production from seaweed based on bench-scale experiments, and large-scale techno-economic feasibility studies for seaweed conversion to biofuels and bioenergy. In addition, the main problems expected with the commercialization of seaweed-based biofuels will be identified. Finally, the current status of seaweed biorefinery technology and the author's views on its promising future will be summarized.

• Membrane Journal
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• v.32 no.5
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• pp.292-303
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• 2022

An eco-friendly energy conversion device without the emission of pollutants has gained much attention due to the rapid use of fossil fuels inducing carbon dioxide emissions ever since the first industrial revolution in the 18th century. Polymer electrolyte membrane fuel cells (PEMFCs) that can produce water during the reaction without the emission of carbon dioxide are promising devices for automotive and residential applications. As a key component of PEMFCs, polymer electrolyte membranes (PEMs) need to have high proton conductivity and physicochemical stability during the operation. Currently, perfluorinated sulfonic acid-based PEMs (PFSA-PEMs) have been commercialized and utilized in PEMFC systems. Although the PFSA-PEMs are found to meet these criteria, there is an ongoing need to improve these further, to be useful in practical PEMFC operation. In addition, the well-known drawbacks of PFSA-PEMs including low glass transition temperature and high gas crossover need to be improved. Therefore, this review focused on recent trends in the development of high-performance PFSA-PEMs in three different ways. First, control of the side chain of PFSA copolymers can effectively improve the proton conductivity and thermal stability by increasing the ion exchange capacity and polymer crystallinity. Second, the development of composite-type PFSA-PEMs is an effective way to improve proton conductivity and physical stability by incorporating organic/inorganic additives. Finally, the incorporation of porous substrates is also a promising way to develop a thin pore-filling membrane showing low membrane resistance and outstanding durability.

• Journal of Life Science
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• v.33 no.3
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• pp.287-294
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• 2023

Healthy adipose tissue is critical for preventing obesity by maintaining metabolic homeostasis. Adipose tissue plays an important role in energy homeostasis through glucose and lipid metabolism. Depending on nutritional status, adipose tissue expands to store lipids or can be consumed by lipolysis. The role of adipose tissue as an endocrine organ is emerging, and many studies have reported that there are various adipose tissue hormones that communicate with other organs and tissues through metabolic signaling. For example, leptin, a representative peptide hormone secreted from adipose tissues (adipokine), circulates and targets the central nervous system of the brain for appetite regression. Furthermore, adipocytes secrete inflammatory cytokines to target immune cells in adipose tissues. Not surprisingly, adipocytes can secrete fatty acid-derived hormones (lipokine) that bind to their specific receptors for paracrine and endocrine action. To understand organ crosstalk by adipose tissue hor- mones, specific metabolic signaling in adipocytes and other communicating cells should be defined. The dysfunction of metabolic signaling in adipocytes occurs in unhealthy adipose tissue in overweight and obese conditions. Therapy targeting novel adipose metabolic signaling could potentially lead to the development of an effective anti-obesity drug. This review summarizes the latest updates on adipose tissue hormone and metabolic signaling in terms of obesity and metabolic diseases.

• Journal of Dairy Science and Biotechnology
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• v.41 no.1
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• pp.9-25
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• 2023

Yogurt fermentation is known to be beneficial because it provides a low pH and harsh environment for foodborne pathogens and improves organoleptic properties. Additionally, organic acids produced through fermentation have a good effect on the viscosity and gelling properties of yogurt. Several potential health benefits of probiotic and generally recognized as safe strains have been suggested. Yogurt is the preferred vehicle for delivering probiotics to health-conscious consumers. Therefore, manufacturers of probiotic beverages must comply with the relevant regulations. The development of probiotic yogurt begins with the selection of strains with safety and functional properties of probiotics. The selected probiotic strain should be technically suitable for viability and improve organoleptic quality while maintaining the number of bacteria above the standard value during processing and storage conditions. In addition, the efficacy of probiotic strains contained in yogurt should be investigated, confirmed, and approved according to well-designed clinical trials. Although various methods are used to detect probiotic strains, the recently widely used next generation sequencing method can be actively utilized. In the future, more research should be conducted with the latest methods to identify probiotic functions and accurately detect probiotic strains.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.305-318
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• 2022

To minimize the effects of aging-related comorbidities and to maintain a good quality of life and physical independence for a longer period, the improvement of lifestyle and dietary habits is essential, and healthy foods can be helpful. Among them, medicinal plant such as ginseng (Panax ginseng) and bellflower (Platycodon grandiflorum) contain natural functional substances and have been used for disease treatment and prevention since ancient times. This review summarizes the scientific of these treatments basis by investigating the pharmacological and pharmacokinetic effects of major functional substances on the aging-related health effects of Panax ginseng and Platycodon grandiflorum. The main functional substances of Panax ginseng and Platycodon grandiflorum are saponins, which have a similar molecular structure and confirmed anti-inflammatory, antioxidant, neuroprotective, anticancer, and anti-metabolic syndrome effects (improvement of hypertension, dyslipidemia, diabetes, and obesity). Both types of saponins in Panax ginseng (Ginseonside) and Platycodon grandiflorum (Platycoside) have very low absorption profiles in their purified state, but methods to increase absorption in the body through extraction or fermentation have been studied.

• Journal of Life Science
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• v.33 no.2
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• pp.208-215
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• 2023

In recent decades, the field of aging research has progressed from the genetic and cellular levels to in vivo models of blood exchange. Since genes capable of extending the lifespan in C. elegance have been reported, various potential target molecules have been discovered through genomics, proteomics, metabolomics, and transcriptomics. Accordingly, research on the interactions between target molecules has also been increasing. The parabiosis method, in which two experimental animals are surgically combined, was introduced, and a factor that could reverse the aging phenomenon was discovered using this method. The parabiosis method is used to find more accurate and effective aging-reversal factors that could exist in young blood. As more new evidence has been revealed, the parabiosis method has established a new paradigm for aging research. Moreover, a device capable of exchanging blood elaborately in laboratory animals was published in 2022 and presented new results necessary for aging reversal. Since GDF11, was reported, many other anti-aging candidates that are soluble factors in blood, such as β2m, TIMP2, VCAM1, Gpld1, and clusterin, have been discovered. In addition, mcicroglia cells and neuroinflammation have been directly proven to be aging factors. These latest research results were obtained by parabiosis, the newly designed device for plasmapheresis, and injecting young blood or conditioned blood methods. In this review, we discuss the latest research results using the device and young blood administration in old mice.

• Journal of Life Science
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• v.33 no.2
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• pp.216-226
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• 2023

Since nylon 66, a polyamide resin, has been developed and applied to toothbrush bristles, plastic consumption has increased rapidly every year, along with the increase in the amount of plastic discarded. Among the various forms of plastic debris produced by the decomposition of plastics, microplastics with a size of less than 5 mm are widely distributed in the environment, which poses a threat not only to the environment but also to animals and humans. The pathway through which microplastics enter the human body is known as ingestion by water and food, inhalation from air, and skin contact. Microplastics introduced into the human body affect human health. Recently, food-related studies have begun to be reported among microplastics-related studies, and analyses of the presence of microplastics in processed foods, such as canned foods, dried seaweed, beverages, beer, milk, sugar, and honey, are underway. Here, we present trends in the production and consumption of plastics, the generation of microplastics, the route of human inflow and human risk, and the microplastics present in processed foods, which are limited but have recently been reported. Thus far, studies on microplastics and risk assessment in processed foods have been insufficient, but microplastics are gradually being recognized as a factor that affects the environment and food. Future studies are expected to have implications for regulations regarding microplastics present in processed foods.

• Journal of Life Science
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• v.33 no.1
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• pp.102-113
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• 2023

This review discusses the cellular and molecular mechanisms by which the endometrial estrogen and progesterone receptors regulate local estrogen production, expression of the specific estrogen receptors, progesterone resistance, inflammatory responses and the differentiation and survival of endometriotic cells in endometrial inflammation. The epigenetic aberrations of endometrial stromal cells play an important role in the pathogenesis and progression of endometriosis. In particular, differential methylation of the estrogen receptor genes changes in the stromal cells the dominancy of estrogen receptor from ERα into ERβ, and results in the abnormal estrogen responses including inflammation, progesterone resistance and the disturbance of retinoid synthesis. These stromal cells also stimulate local estrogen production in response to PGE2 and the SF-1 mediated induction of steroidogenic enzyme expression, and the increased estradiol then feeds back into the ERβ to repeat the vicious inflammatory cycle through the activation of COX-2. In addition, high levels of ERβ expression may also change the chromatin structure of endometrial mesenchymal stem cells, and together with the repeated menstrual cycles can induce formation of the endometriotic tissue. The cascade of these serial events then leads to cell adhesion, angiogenesis and survival of the differentiation-disregulated stromal cells through the action of inflammatory factors such as ERβ-mediated estrogen, TNF-α and TGF-β1. Therefore, understanding of the dynamic hormonal changes during the menstrual cycle and the corresponding signal transduction mechanisms of the related nuclear receptors in endometrium would provide new insights for treating inflammatory diseases such as the endometriosis.

• Membrane Journal
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• v.32 no.6
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• pp.427-441
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• 2022

Polymer electrolyte membrane (PEM) serving as a separator that can prevent the permeation of unreacted fuels as well as an electrolyte that selectively transports protons from the anode to the cathode has been considered a key component of polymer electrolyte membrane fuel cell (PEMFC). The perfluorinated sulfonic acid-based PEMs, represented by Nafion®, have been commercialized in PEMFC systems due to their high proton conductivity and chemical stability. Nevertheless, these PEMs have several inherent drawbacks including high manufacturing costs by the complex synthetic processes and environmental problems caused by producing the toxic gases. Although numerous studies are underway to address these drawbacks including the development of sulfonated hydrocarbon polymer-based PEMs (SHP-PEMs), which can easily control the polymer structures, further improvement of PEM performances and durability is necessary for practical PEMFC applications. Therefore, this study focused on the various strategies for the development of SHP-PEMs with outstanding performance and durability by 1) introducing cross-linked structures, 2) incorporating organic/inorganic composites, and 3) fabricating reinforced-composite membranes using porous substrates.

• Membrane Journal
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• v.32 no.6
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• pp.442-455
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• 2022

High-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has been studied as an alternative to low-temperature PEMFC due to its fast activation of electrodes and high resistance to electrode poisoning by carbon monoxide. It is highly required to develop stable PEMs operating at high temperatures even doped by ion-conducting materials for the development of high-performance and durable HT-PEMFC systems. A number of studies have been conducted to develop polybenzimidazole (PBI)-based PEMs for applications in HT-PEMFC due to their high interaction with doped ion-conducting materials and outstanding thermomechanical stability under high-temperature operation. This review focused on the development of PBI-based PEMs showing high performance and durability. Firstly, the characteristic behavior of PBI-based PEMs doped with various ion-conducting materials including phosphoric acid was systematically investigated. And then, a comparison of the physicochemical properties of the PEMs according to the different membrane manufacturing processes was conducted. Secondly, the incorporation of porous polytetrafluoroethylene substrate and/or inorganic composites to PBI matrix to improve the membrane performances was studied. Finally, the construction of cross-linked structures into PBI-based PEM systems by polymer blending method was introduced to improve the PEM properties.