• Wind and Structures
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• v.28 no.4
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• pp.255-270
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• 2019

Aerodynamic configurations of bridge decks have significant effects on the aerostatic torsional divergence and flutter forsuper long-span bridges, which are onset for selection of suitable bridge decksfor those bridges. Based on a cable-stayed bridge with double main spans of 1500 m, considering typical twin-box, stiffening truss and closed-box section, which are the most commonly used form of bridge decks and assumed that the rigidity of those section is completely equivalent, are utilized to investigate the effects of aerodynamic configurations of bridge decks on aerodynamic instability performance comprised of the aerostatic torsional divergence and flutter, by means of wind tunnel tests and numerical calculations, including three-dimensional (3D) multimode flutter analysis and nonlinear aerostatic analysis. Regarding the aerostatic torsional divergence, the results obtained in this study show twin-box section is the best, closed-box section the second-best, and the stiffening truss section the worst. Regarding the flutter, the flutter stability of the twin-box section is far better than that of the stiffening truss and closed-box section. Furthermore, wind-resistance design depends on the torsional divergence for the twin-box and stiffening truss section. However, there are obvious competitive relationships between the aerostatic torsional divergence and flutter for the closed-box section. Flutter occur before aerostatic instability at initial attack angle of $+3^{\circ}$ and $0^{\circ}$, while the aerostatic torsional divergence occur before flutter at initial attack angle of $-3^{\circ}$. The twin-box section is the best in terms of both aerostatic and flutter stability among those bridge decks. Then mechanisms of aerostatic torsional divergence are revealed by tracking the cable forces synchronous with deformation of the bridge decksin the instability process. It was also found that the onset wind velocities of these bridge decks are very similar at attack angle of $-3^{\circ}$. This indicatesthat a stable triangular structure made up of the cable planes, the tower, and the bridge deck greatly improves the aerostatic stability of the structure, while the aerodynamic effects associated with the aerodynamic configurations of the bridge decks have little effects on the aerostatic stability at initial attack angle of $-3^{\circ}$. In addition, instability patterns of the bridge depend on both the initial attack angles and aerodynamic configurations of the bridge decks. This study is helpful in determining bridge decksfor super long-span bridges in future.

• Membrane Journal
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• v.31 no.3
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• pp.228-240
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• 2021

The organic solvent robust polybenzimidazole (PBI) membranes were prepared as organic solvent nanofiltration (OSN) membrane for the recycling of alcoholic solvents using non-solvent induced phase separation with different dope solution concentration and coagulant composition of water/ethanol mixtures to control the membrane morphology and permeation performance. Investigation on crosslinking of polybenzimidazole indicated that the membrane crosslinked with dibromoxylene (DBX) had enough mechanical strength and solvent resistance to be applied as a OSN membranes. The crosslinked PBI membrane prepared by more than 20wt% dope concentration coagulated in water showed a rejection of > 90% to Congo Red (MW of 696.66 g/mol) while pure ethanol permeances was more than 22.5 LMH/bar at 5 bar. Investigation on coagulant composition indicated that ethanol permeance through crosslinked PBI OSN membrane increased with increasing of ethanol concentration in water/ethanol mixture coagulants.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.89-96
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• 2021

The aim of this study is to examine the effect of Caulerpa okamurae ethanol extract (COE) on glucose metabolism and insulin sensitivity as one of the drug targets for treatment of type2 diabetes. COE significantly inhibited protein tyrosine phosphatase (PTP1B) and dipeptidyl peptidase-IV (DPP-IV) enzyme activities in vitro assay. Also, COE significantly enhanced the glucose uptake and the expression of insulin receptor substrate-1 (IRS-1) and glucose transporter4 (GLUT4) proteins in 3T3-L1 adipocytes or zebrafish larvae compared with control. In dexamethasone-induced resistance model of L6 myotubes, the protein expression of insulin signaling and glucose uptake was effectively increased by the treatment of COE. In contrast, the elevated phosphorylation of IRS-1 Ser307 was normally suppressed by treatment of COE. However, COE had no effect on insulin secretion in pancreatic beta cells. Thus, our results suggest that COE improves the glucose metabolism and insulin sensitivity through the regulation of insulin signaling and GLUT4 protein in insulin's target cells and zebrafish larvae.

• Animal Bioscience
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• v.35 no.7
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• pp.964-974
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• 2022

Objective: The highly pathogenic avian influenza virus (HPAIV) is a threat to the poultry industry and economy and remains a potential source of pandemic infection in humans. Antiviral genes are considered a potential factor for studies on HPAIV resistance. Therefore, in this study, we investigated gene expression related to the mitogen-activated protein kinase (MAPK) signaling pathway by comparing non-infected, HPAI-infected resistant, and susceptible Ri chicken lines. Methods: Resistant (Mx/A; BF2/B21) and susceptible Ri chickens (Mx/G; BF2/B13) were selected by genotyping the Mx and BF2 genes. Then, the tracheal tissues of non-infected and HPAIV H5N1 infected chickens were collected for RNA sequencing. Results: A gene set overlapping test between the analyzed differentially expressed genes (DEGs) and functionally categorized genes was performed, including biological processes of the gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathways. A total of 1,794 DEGs were observed between control and H5N1-infected resistant Ri chickens, 432 DEGs between control and infected susceptible Ri chickens, and 1,202 DEGs between infected susceptible and infected resistant Ri chickens. The expression levels of MAPK signaling pathway-related genes (including MyD88, NF-κB, AP-1, c-fos, Jun, JunD, MAX, c-Myc), cytokines (IL-1β, IL-6, IL-8), type I interferons (IFN-α, IFN-β), and IFN-stimulated genes (Mx1, CCL19, OASL, and PRK) were higher in H5N1-infected than in non-infected resistant Ri chickens. MyD88, Jun, JunD, MAX, cytokines, chemokines, IFNs, and IFN-stimulated expressed genes were higher in resistant-infected than in susceptible-infected Ri chickens. Conclusion: Resistant Ri chickens showed higher antiviral activity compared to susceptible Ri chickens, and H5N1-infected resistant Ri chickens had immune responses and antiviral activity (cytokines, chemokines, interferons, and IFN-stimulated genes), which may have been induced through the MAPK signaling pathway in response to H5N1 infection.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.27-35
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• 2004

Recalcitrant 4-t-Octylphenol used as a surfactant was subjected to the biodegradation with wood rot fungi, Basidioradulum molare and Schizopora paradoxa. Two fungi were grown in the culture medium containing various concentrations of 4-t-Octylphenol in order to investigate their resistance against 4-t-octylphenol Schizopora paradoxa was reached to the full growth within 14 incubation days in the concentration of more than 200 ppm of 4-t-Octylphenol, while Basidioradulum molare showed the inhibitory mycelium growth as the concentration was increased Schizopora paradoxa and Basidioradulum molare biodegraded 95% and 36% of initial concentration of 4-t-Octylphenol at first incubation day, respectively. However, the biodegradation capability reached to more than 95% after 3 incubation days. During the biodegradation of 4-t-Octylphenol, the activity of manganese dependent peroxidase was induced by the addition of 4-t-Octylphenol in the culture medium of Schizopora paradoxa, but that of laccase was maximal before the addition. The reduction of estrogenecity was assayed by MCF-7 cell proliferation test and measurement of pS2 mRNA expression. The level of pS2 mRNA was decreased down to the level of baseline at first incubation day. Also, estrogenecity of 4-t-Ocrylphenol completely disappeared after treatment with supernatant by Schizopora paradoxa and Basidioradulum molare from first incubation day of culture down to the levels of vehicle.

• Biomolecules & Therapeutics
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• v.30 no.6
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• pp.553-561
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• 2022

Chronic myeloid leukemia (CML) is a slowly progressing hematopoietic cell disorder. Sphingosine kinase 1 (SPHK1) plays established roles in tumor initiation, progression, and chemotherapy resistance in a wide range of cancers, including leukemia. However, small-molecule inhibitors targeting SPHK1 in CML still need to be developed. This study revealed the role of SPHK1 in CML and investigated the potential anti-leukemic activity of hirsuteine (HST), an indole alkaloid obtained from the oriental plant Uncaria rhynchophylla, in CML cells. These results suggest that SPHK1 is highly expressed in CML cells and that overexpression of SPHK1 represents poor clinical outcomes in CML patients. HST exposure led to G2/M phase arrest, cellular apoptosis, and downregulation of Cyclin B1 and CDC2 and cleavage of Caspase 3 and PARP in CML cells. HST shifted sphingolipid rheostat from sphingosine 1-phosphate (S1P) towards the ceramide coupled with a marked inhibition of SPHK1. Mechanistically, HST significantly blocked SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways. In addition, HST can be docked with residues of SPHK1 and shifts the SPHK1 melting curve, indicating the potential protein-ligand interactions between SPHK1 and HST in both CML cells. SPHK1 overexpression impaired apoptosis and proliferation of CML cells induced by HST alone. These results suggest that HST, which may serve as a novel and specific SPHK1 inhibitor, exerts anti-leukemic activity by inhibiting the SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways in CML cells, thus conferring HST as a promising anti-leukemic drug for CML therapy in the future.

• Journal of Life Science
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• v.32 no.6
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• pp.476-481
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• 2022

Ubiquitin signaling regulates virtually all aspects of eukaryotic biology and dynamic processes in which protein substrates are modified by ubiquitin. To regulate these processes, deubiquitinating enzymes (DUBs) cleave ubiquitin or ubiquitin-like proteins from these substrates. DUBs have been implicated in the pathogenesis of cancer, leading to the development of increasing numbers of small-molecule DUB inhibitors. On the other hand, recent studies have focused on the function of DUBs in metabolic diseases such as obesity, diabetes, and fatty liver diseases. DUBs play a positive or negative role in the progression and development of metabolic diseases. Their involvement in cell pathology and regulation of major transcription factors in metabolic syndrome has been examined in vitro and in animal and human biopsies. UCH, USP7, and USP19 were linked to adipocyte differentiation, body weight gain, and insulin resistance in genetic or diet-induced obesity. CYLD, USP4, and USP18 were found to be closely associated with fatty liver diseases. In addition, these liver diseases were accompanied by body weight change in certain cases. Collectively, in this review, we discuss the current understanding of DUBs in metabolic diseases with a particular focus on obesity. We also provide basic knowledge and regulatory mechanisms of DUBs and suggest these enzymes as therapeutic targets for metabolic diseases.

• Research in Plant Disease
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• v.28 no.1
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• pp.1-18
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• 2022

Volatiles exist ubiquitously in nature. Volatile compounds produced by plants and microorganisms confer inter-kingdom and intra-kingdom communications. Autoinducer signaling molecules from contact-based chemical communication, such as bacterial quorum sensing, are relayed through short distances. By contrast, biogenic volatiles derived from plant-microbe interactions generate long-distance (>20 cm) alarm signals for sensing harmful microorganisms. In this review, we discuss prior work on volatile compound-mediated diagnosis of plant diseases, and the use of volatile packaging and dispensing approaches for the biological control of fungi, bacteria, and viruses. In this regard, recent developments on technologies to analyze and detect microbial volatile compounds are introduced. Furthermore, we survey the chemical encapsulation, slow-release, and bio-nano techniques for volatile formulation and delivery that are expected to overcome limitations in the application of biogenic volatiles to modern agriculture. Collectively, technological advances in volatile compound detection, packaging, and delivery provide great potential for the implementation of ecologically-sound plant disease management strategies. We hope that this review will help farmers and young scientists understand the nature of microbial volatile compounds, and shift paradigms on disease diagnosis and management to aromatic (volatile-based) agriculture.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.93-105
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• 2021

In this study, we evaluated the effect of soil fine contents on the formation of underground cavities and ground cave-ins induced by damaged sewer pipes. Simulating the domestic rainfall conditions and ground conditions, model tests were performed under three different fine particle contents conditions (7.5%, 15%, and 25%). By repeating the groundwater supply and drainage twice, ground settlement and the amount of discharged soil were obtained. Also, digital images were taken at regular time intervals during the model tests, and internal displacement and deformation were measured using PIV technique. As the cycles were repeated, the soil with high fine content showed greater resistance to the formation of underground cavities. The ground cave-ins, identified by the collapse of the surface, occurred only when the fine particle content was 15%. It is presumed to be due to the suffusion phenomenon; further study was needed to investigate the effect of fine particle contents on the suffusion phenomenon and associated changes of soil strength.

• Journal of Life Science
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• v.32 no.2
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• pp.175-188
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• 2022

Relaxin has been demonstrated to have regulatory functions on both the smooth muscle and extracellular matrix (ECM) of blood vessels and fibrotic organs. The diverse mechanisms by which relaxin acts on small resistance arteries and fibrotic organs, including the bladder, are reviewed here. Relaxin induces vasodilation by inhibiting the contractility of vascular smooth muscles and by increasing the passive compliance of vessel walls through the reduction of ECM components, such as collagen. The primary cellular mechanism whereby relaxin induces arterial vasodilation is mediated by the endothelium-dependent production of nitric oxide (NO) through the activation of RXFP1/PI3K, Akt phosphorylation, and eNOS. In addition, relaxin triggers different alternative pathways to enhance the vasodilation of renal and mesenteric arteries. In small renal arteries, relaxin stimulates the activation of the endothelial MMPs and EtB receptors and the production of VEGF and PlGF to inhibit myogenic contractility and collagen deposition, thereby bringing about vasodilation. Conversely, in small mesenteric arteries, relaxin augments bradykinin (BK)-evoked relaxation in a time-dependent manner. Whereas the rapid enhancement of the BK-mediated relaxation is dependent on IK_Ca channels and subsequent EDH induction, the sustained relaxation due to BK depends on COX activation and PGI₂. The anti-fibrotic effects of relaxin are mediated by inhibiting the invasion of inflammatory immune cells, the endothelial-to-mesenchymal transition (EndMT), and the differentiation and activation of myofibroblasts. Relaxin also activates the NOS/NO/cGMP/PKG-1 pathways in myofibroblasts to suppress the TGF-β1-induced activation of ERK1/2 and Smad2/3 signaling and deposition of ECM collagen.