• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1124-1131
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• 2016

In this study, the global proteome of the IPEC-J2 cell line was evaluated using ultra-high performance liquid chromatography coupled to a quadrupole Q Exactive^™ Orbitrap mass spectrometer. Proteins were isolated from highly confluent IPEC-J2 cells in biological replicates and analyzed by label-free mass spectrometry prior to matching against a porcine genomic dataset. The results identified 1,517 proteins, accounting for 7.35% of all genes in the porcine genome. The highly abundant proteins detected, such as actin, annexin A2, and AHNAK nucleoprotein, are involved in structural integrity, signaling mechanisms, and cellular homeostasis. The high abundance of heat shock proteins indicated their significance in cellular defenses, barrier function, and gut homeostasis. Pathway analysis and annotation using the Kyoto Encyclopedia of Genes and Genomes database resulted in a putative protein network map of the regulation of immunological responses and structural integrity in the cell line. The comprehensive proteome analysis of IPEC-J2 cells provides fundamental insights into overall protein expression and pathway dynamics that might be useful in cell adhesion studies and immunological applications.

• 한국소음진동공학회논문집
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• 제20권10호
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• pp.915-922
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• 2010

This paper presents an efficient method for determining the forced response of a spinning flexible disk-spindle system supported by fluid dynamic bearings(FDBs) in a computer hard disk drive(HDD). The spinning flexible disk-spindle system is represented by the asymmetric finite element equations of motion originating from the asymmetric dynamic coefficients of the FDBs and the gyroscopic moment of a spinning disk-spindle system. The proposed method utilizes only the right eigenvectors of the eigenvalue problem to transform the large asymmetric finite element equations of motion into a small number of coupled equations, guaranteeing the accuracy of their numerical integration. The results are then back-substituted into the equations of motion to determine the forced response. The effectiveness of the proposed method was verified by comparing it with the responses from the classical methods of mode superposition with the general eigenvalue problems, and mode superposition with modal approximation. The proposed method was shown to be effective in determining the forced response represented by the asymmetric finite element equations of motion of a spinning flexible disk-spindle system supported by FDBs.

• Wind and Structures
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• 제18권4호
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• pp.347-373
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• 2014

Since its development in the early 1980's the force balance technique has become a standard method in the efficient determination of structural loads and responses. Its usefulness lies in the simplicity of the physical model, the relatively short records required from the wind tunnel testing and its versatility in the use of the data for different sets of dynamic properties. Its major advantage has been the ability to provide results in a timely manner, assisting the structural engineer to fine-tune their building at an early stage of the structural development. The analysis of the wind tunnel data has evolved from the simple un-coupled system to sophisticated methods that include the correction for non-linear mode shapes, the handling of complex geometry and the handling of simultaneous measurements on multiple force balances for a building group. This paper will review some of the components in the force balance data analysis both in historical perspective and in its current advancement. The basic formulation of the force balance methodology in both frequency and time domains will be presented. This includes all coupling effects and allows the determination of the resultant quantities such as resultant accelerations, as well as various load effects that generally were not considered in earlier force balance analyses. Using a building model test carried out in the wind tunnel as an example case study, the effects of various simplifications and omissions are discussed.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2019-2028
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• 2018

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at $200{\mu}mo/m^2/s$ under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

• Smart Structures and Systems
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• 제24권3호
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• pp.403-414
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• 2019

Offshore drilling has become a key process for obtaining oil. Offshore platforms have many applications, including oil exploration and production, navigation, ship loading and unloading, and bridge and causeway support. However, vibration problems caused by severe environmental loads, such as ice, wave, wind, and seismic loads, threaten the functionality of platform facilities and the comfort of workers. These concerns may result in piping failures, unsatisfactory equipment reliability, and safety concerns. Therefore, the vibration control of offshore platforms is essential for assuring structural safety, equipment functionality, and human comfort. In this study, an optimal multiple tuned mass damper (MTMD) system was proposed to mitigate the excessive vibration of a three-dimensional offshore platform under ice and earthquake loadings. The MTMD system was designed to control the first few dominant coupled modes. The optimal placement and system parameters of the MTMD are determined based on controlled modal properties. Numerical simulation results show that the proposed MTMD system can effectively reduce the displacement and acceleration responses of the offshore platform, thus improving safety and serviceability. Moreover, this study proposes an optimal design procedure for the MTMD system to determine the optimal location, moving direction, and system parameters of each unit of the tuned mass damper.

• 한국해양공학회지
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• 제33권2호
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• pp.106-115
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• 2019

The interaction between a sloshing liquid damper (SLD) tank and a rectangular pontoon was investigated under the assumption of the linear potential theory. The eigenfunction expansion method was used not only for the sloshing problem in the SLD tank but also for analyzing the motion responses of a rectangular pontoon in waves. If the frictional damping due to the viscosity of the SLD tank was ignored, the effect of the SLD appeared to be an added mass in the coupled equation of motion. The installation of the SLD tank had a greater effect on the roll motion response than the sway and heave motion of the pontoon. One resonance peak for rolling motion showed up in the case of a frozen liquid in the SLD tank. However, if liquid motion in the SLD tank was allowed, two peaks appeared around the first natural frequency of the fluid in the SLD tank. In particular, the peak value located in the low-frequency region had a relatively large value, and the peak frequency located in the high-frequency region moved into the high-frequency region as the depth of the liquid in the tank increased.

• Steel and Composite Structures
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• 제39권3호
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• pp.261-274
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• 2021

In a railway bridge, the CRTS II slab ballastless track is subjected to interlayer connection failures, such as void under slab, mortar debonding, and fastener fracture. This study investigates the influences of interlayer connection failure on the safe operation of high-speed trains. First, a train-track-bridge coupled vibration model and a bridge-track deformation model are established to study the running safety of a train passing a deformed bridge with interlayer connection failure. For each type of the interlayer connection failure, the effects of the failure locations and ranges on the track irregularity are studied using the deformation model. Under additional bridge deformation, the effects of interlayer connection failure on the dynamic responses of the train are investigated by using the track irregularity as the excitation to the vibration model. Finally, parametric studies are conducted to determine the thresholds of additional bridge deformations considering interlayer connection failure. Results show that the interlayer connection failure significantly affects the running safety of high-speed train and must be considered in determining the safety thresholds of additional bridge deformation in the asset management of high-speed railway bridges.

• Computers and Concrete
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• 제24권4호
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• pp.347-367
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• 2019

This work investigates the effect of Winkler/Pasternak/Kerr foundation and porosity on dynamic behavior of FG plates using a simple quasi-3D hyperbolic theory. Four different patterns of porosity variations are considered in this study. The used quasi-3D hyperbolic theory is simple and easy to apply because it considers only four-unknown variables to determine the four coupled vibration responses (axial-shear-flexion-stretching). A detailed parametric study is established to evaluate the influences of gradient index, porosity parameter, stiffness of foundation parameters, mode numbers, and geometry on the natural frequencies of imperfect FG plates.

• Biomolecules & Therapeutics
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• 제29권4호
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• pp.427-433
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• 2021

Free fatty acid receptor 2 (FFA2, also known as GPR43), a G-protein-coupled receptor, has been known to recognize short-chain fatty acids and regulate inflammatory responses. FFA2 gene deficiency exacerbated disease states in several models of inflammatory conditions including asthma. However, in vivo efficacy of FFA2 agonists has not been tested in allergic asthma. Thus, we investigated effect of 4-chloro-α-(1-methylethyl)-N-2-thiazoylylbenzeneacetanilide (4-CMTB), a FFA2 agonist, on antigen-induced degranulation in RBL-2H3 cells and ovalbumin-induced allergic asthma in BALB/c mice. Treatment of 4-CMTB inhibited the antigen-induced degranulation concentration-dependently. Administration of 4-CMTB decreased the immune cell numbers in the bronchoalveolar lavage fluid and suppressed the expression of inflammatory Th2 cytokines (IL-4, IL-5, and IL-13) in the lung tissues. Histological studies revealed that 4-CMTB suppressed mucin production and inflammation in the lungs. Thus, results proved that FFA2 functions to suppress allergic asthma, suggesting 4-CMTB activation of FFA2 as a therapeutic tool for allergic asthma.

• BMB Reports
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• 제55권8호
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• pp.407-412
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• 2022

A well-controlled inflammatory response is crucial for the recovery from injury and maintenance of tissue homeostasis. The anti-inflammatory response of 2-methoxycinnamaldehyde (2-MCA), a natural compound derived from cinnamon, has been studied; however, the underlying mechanism on macrophage has not been fully elucidated. In this study, LPS-stimulated production of TNF-α and NO was reduced by 2-MCA in macrophages. 2-MCA significantly activated the NRF2 pathway, and expression levels of autophagy-associated proteins in macrophages, including LC3 and P62, were enhanced via NRF2 activation regardless of LPS treatment, suggesting the occurrence of 2-MCA-mediated autophagy. Moreover, evaluation of autophagy flux using luciferase-conjugated LC3 revealed that incremental LC3 and P62 levels are coupled to enhanced autophagy flux. Finally, reduced expression levels of TNF-α and NOS2 by 2-MCA were reversed by autophagy inhibitors, such as bafilomycin A1 and NH4Cl, in LPS-stimulated macrophages. In conclusion, 2-MCA enhances autophagy flux in macrophages via NRF2 activation and consequently reduces LPS-induced inflammation.