• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.373-384
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• 2016

The membrane-aerated biofilm reactor (MABR) is a promising municipal wastewater treatment process. In this study, two cross-flow MABRs were constructed to explore the carbon and nitrogen removal performance and bacterial succession, along with changes of influent loading shock comprising flow velocity, COD, and NH₄-N concentrations. Redundancy analysis revealed that the function of high flow velocity was mainly embodied in facilitating contaminants diffusion and biosorption rather than the success of overall bacterial populations (p > 0.05). In contrast, the influent NH₄-N concentration contributed most to the variance of reactor efficiency and community structure (p < 0.05). Pyrosequencing results showed that Anaerolineae, and Beta- and Alphaproteobacteria were the dominant groups in biofilms for COD and NH₄-N removal. Among the identified genera, Nitrosomonas and Nitrospira were the main nitrifiers, and Hyphomicrobium, Hydrogenophaga, and Rhodobacter were the key denitrifiers. Meanwhile, principal component analysis indicated that bacterial shift in MABR was probably the combination of stochastic and deterministic processes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.573-579
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• 2009

A thermal mass air flow sensor, which consists of a micro-heater and thermal sensors on the silicon-nitride thin membrane structure, is micro-fabricated by MEMS processes. Three thermo-resistive sensors, one for the measurement of microheater temperature, the others for the measurement of membrane temperature upstream and downstream of the micro-heater respectively, are used. The micro-heater is operated under the constant temperature difference mode via a real time controller, based on inlet air temperature. Two design models for microfabricated flow sensor are compared with experimental results and confirmed their applicabilities and limitations. The thermal characteristics are measured to find the best flow indicator. It is found that two normalized temperature indicators can be adopted with some advantages in practice. The flow sensor with this control mode can be adopted for wide capability of high speed and sensitivity in the very low and medium velocity ranges.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.104-109
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• 2005

The catalyst layer design is one of the most important factors to enhance the performance of PEMFC(Proton Exchange Membrane Fuel Cell) system. The hydrophobic and ion conductive type is studied for the MEA(Membrane Electrolyte Assembly). It is found that those have some limitations for performance enhancement when they are used separately. Thus, the dual catalyst type, a mixed model, is developed for the better MEA performance. In the meantime, the design of flow field plate is subsequently carried out in order to give more enhanced output during its operation. The conductivity of flow field plate showed better performance in the case of manufactured by the more compressed process(20MPa) than by the less compressed process(10MPa). The micro-structure of the flow field plate is examined in details using SEM(Scanning Electron Microscope) to analyse the effects on the different compression processes.

• Food Science and Biotechnology
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• v.14 no.3
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• pp.380-386
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• 2005

Optimal conditions of ultrafiltration (UF) and nanofiltration (NF) were investigated for separation and concentration of isoflavones and oligosaccharides from Sunmul. Levels of COD, BOD, and suspended solids (SS) in UF and NF permeates were also determined to evaluate effectiveness of these processes for reducing water pollution. Optimal UF operation conditions to achieve minimal fouling and maximal flux were $33-34^{\circ}C$ operating temperature and 2.3-2.4 bar trans-membrane pressure. Recovery yields of isoflavones and oligosaccharides in UF retentate were 11.49-28.16% and 12.77-27.57%, respectively. Increase in volumetric concentration factor (VCF) resulted in more functional compounds of isoflavones and oligosaccharides passing through UF membrane. Total isoflavone and oligosaccharide yields decreased by 3% as VCF increased from 6.0 to 8.0 and from 8.0 to 10.0, while decreased significantly by 10% as VCF decreased from 4.0 to 6.0. Optimal NF operating conditions were 192-195 psig operating pressure at $30-33^{\circ}C$. Total yields of isoflavones and oligosaccharides significantly decreased at VCF 8.0, whereas did not decrease up to VCF 6.0 during NF operation. Therefore, VCF 6.0 was recommended for economical process. COD and BOD decreased by more than 98% after NF process, and SS were not detected after UF process. These results indicated sequential filtration process was useful for separation of isoflavones and oligosaccharides from Sunmul and for reducing water contaminants.

• Molecules and Cells
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• v.44 no.9
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• pp.670-679
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• 2021

Vesicle-associated membrane proteins 721 and 722 (VAMP721/722) are secretory vesicle-localized arginine-conserved soluble N-ethylmaleimide-sensitive factor attachment protein receptors (R-SNAREs) to drive exocytosis in plants. They are involved in diverse physiological processes in plants by interacting with distinct plasma membrane (PM) syntaxins. Here, we show that synaptotagmin 5 (SYT5) is involved in plant defense against Pseudomonas syringae pv tomato (Pst) DC3000 by regulating SYP132-VAMP721/722 interactions. Calcium-dependent stimulation of in vitro SYP132-VAMP722 interaction by SYT5 and reduced in vivo SYP132-VAMP721/722 interaction in syt5 plants suggest that SYT5 regulates the interaction between SYP132 and VAMP721/722. We interestingly found that disease resistance to Pst DC3000 bacterium but not to Erysiphe pisi fungus is compromised in syt5 plants. Since SYP132 plays an immune function to bacteria, elevated growth of surface-inoculated Pst DC3000 in VAMP721/722-deficient plants suggests that SYT5 contributes to plant immunity to Pst DC3000 by promoting the SYP132-VAMP721/722 immune secretory pathway.

• Translational and Clinical Pharmacology
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• v.26 no.3
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• pp.103-110
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• 2018

The human microbiome is known to play an essential role in influencing host health. Extracellular vesicles (EVs) have also been reported to act on a variety of signaling pathways, distally transport cellular components such as proteins, lipids, and nucleic acid, and have immunomodulatory effects. Here we shall review the current understanding of the intersectionality of the human microbiome and EVs in the emerging field of microbiota-derived EVs and their pharmacological potential. Microbes secrete several classes of EVs: outer membrane vesicles (OMVs), membrane vesicles (MVs), and apoptotic bodies. EV biogenesis is unique to each cell and regulated by sophisticated signaling pathways. EVs are primarily composed of lipids, proteins, nucleic acids, and recent evidence suggests they may also carry metabolites. These components interact with host cells and control various cellular processes by transferring their constituents. The pharmacological potential of microbiome-derived EVs as vaccine candidates, biomarkers, and a smart drug delivery system is a promising area of future research. Therefore, it is necessary to elucidate in detail the mechanisms of microbiome-derived EV action in host health in a multi-disciplinary manner.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.25-31
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• 2024

The p97 adenosine triphosphatase is a key player in protein homeostasis, responsible for unfolding ubiquitylated substrates. It engages with various adaptor proteins through its N-terminal domain, with the p97-p47 complex attracting particular attention for its involvement in membrane remodeling. Although the structures of p97 in complex with the Ubiquitin regulatory X (UBX) domain from various adaptors have been reported, the stoichiometry is conflicting. Here, we report the crystal structure of the p97 N-D1 hexamer in complex with the p47 UBX domain at a resolution of 2.7 Å. The structure reveals a stoichiometry of 6:6 between the p97 N-D1 and the p47 UBX domain. These findings provide valuable insights into the binding stoichiometry of p97 N-D1 and p47 UBX domain, which are crucial for understanding the role of p97 and adaptor proteins in cellular processes such as the ubiquitin-proteasome pathway, membrane fusion, and cell cycle regulation.

• Journal of Animal Science and Technology
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• v.66 no.5
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• pp.891-904
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• 2024

The primary cause of sperm quality decline during the freeze-thaw pathway is the peroxidation hazard caused by reactive oxygen species produced by the biological molecules of sperm. Ascorbic acid (Vitamin C) and lycopene are two potent antioxidants that operate to prevent oxidation processes. This study aimed to analyse the effects of ascorbic acid and lycopene on the motility, viability, abnormality and plasma membrane integrity of post-thawed Sapudi rams. Sperm samples were obtained and pooled from six sexually mature Sapudi rams, separated into ten equal proportions and diluted with Tris-egg yolk-glycerol (TEY) extender. Semen was supplemented with 0 (C0; L0), 1 (C1; L1), 2 (C2; L2), 3 (C3; L3) and 4 (C4; L4) mg/100 mL (1%-4%) diluent each of ascorbic acid and lycopene, respectively. Total sperm motility, viability, abnormalities and semen membrane plasma (%) were analysed after thawing. C3 and L3 extenders resulted in higher total motility (p < 0.05) compared to the other extenders, with all treatments higher than that of the control. The extender C3 (p < 0.05) exhibited the highest semen quality. Finally, the current findings show that C3 and L3 can increase the quality of post-thawed Sapudi ram spermatozoa.

• Membrane Journal
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• v.18 no.2
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• pp.157-167
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• 2008

Removal of organic substances and taste/odor control are ones of the main issues in water supply, resulting in introduction of advanced processes such as ozon/GAC, or PAC. However, raw water quality deteriorates, new pollutants advent, so water quality is not acceptable enough even with those existing advanced processes. In this paper, a new advanced water treatment process using PAC slurry blanket, where PAC particles stay in the basin as slurry blanket, coupled with submerged membranes is introduced. A pilot plant $(80m^3/day)$ was installed to assess the performance of this new process using actual raw water, and DOC was removed higher than 90% in the beginning and $70{\sim}80%$ afterwards, while 2-MIB and geosmin were removed completely. This new process still requires future study on process optimization and long-term assessment, however it seems highly possible to countermeasure as a new advanced process with high removal efficiency.

• Membrane Journal
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• v.28 no.1
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• pp.31-36
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• 2018

The purpose of this study is to investigate the changes of sludge characteristics according to the changes of influent sewage flowrate in the advanced wastewater treatment processes including MBR, SBR, and $A_2O$. The ratio of the actual sewage flowrate to the design flowrate is decreased from 100% to 70, 40%, and 10%, and the specific denitrification rate and ammonia oxidation (nitrification) rate was measured. The specific nitrification rate of the sludge collected from the aeration tank of each process was measured at a similar value ($0.10gNH_4/gMLVSS/day$) in all three process under the condition of 100% of sewage flowrate. It has tended to decrease significantly as the sewage flowrate decreased from 70% to 40%. The specific denitrification rate was also decreased by ~50% as the sewage flowrate decreased. However, considering the total nitrogen concentration in the influent and the microbial concentration in the reactor, the changes in kinetic parameter did not affect overall nitrogen removal. Therefore, it can be concluded that stable nitrogen removal will be possible under low influent flowrate condition if the MLVSS concentration is kept high.