Publications by authors named "Jeong Seok Oh"

Affinity precipitation is an attractive method for protein purification due to its many advantages, including the rapid capture of target proteins, simple processing, high specificity, and ease of scale-up. We previously reported a robust antibody purification method using Ca-dependent precipitation of ZZ-hCSQ2, a fusion protein of human calsequestrin 2, and the antibody-binding protein ZZ. However, the stability of this fusion protein was not sufficiently high for industrial use because the antibody recovery yield decreased to 60% after being reused 10 times.

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We configured a long-distance ranging apparatus to test the principle of dual-comb time-of-flight measurement using ultrashort lasers. Emphasis was given to the evaluation of open-air performance quantitatively in terms of the measurement resolution and stability. The test results revealed that our dual-comb asynchronous optical pulse sampling permits micrometer-resolved ranging with a repeatability of 2.

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Research questions in the human sciences often seek to answer if and when a process changes across time. In functional MRI studies, for instance, researchers may seek to assess the onset of a shift in brain state. For daily diary studies, the researcher may seek to identify when a person's psychological process shifts following treatment.

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High-damping rubber composites were prepared by mixing ethylene propylene diene monomer rubber (EPDM) with slide-ring (SR) materials using a two-roll mill, followed by a compression molding technique. SR material has a novel supramolecular structure with unique softness and slidable crosslink junctions. The mechanical strength, thermal stability, compression set property, and damping performance of the composites were investigated.

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The development of smart elastomeric materials with inherent self-repairing abilities after mechanical damage has important technological and scientific implications, particularly in regard to the durability and life cycle of rubber products. The interest in self-healing materials for automotive applications is rapidly growing along with the increasing importance of vehicle scratch quality and quantity. The creation of a reversible network by noncovalent ionic cross-linking in elastomer/rubber blends is an effective approach to generate the self-healing phenomenon, with reprocessing and recycling properties.

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The pairwise maximum entropy model (pMEM) has recently gained widespread attention to exploring the nonlinear characteristics of brain state dynamics observed in resting-state functional magnetic resonance imaging (rsfMRI). Despite its unique advantageous features, the practical application of pMEM for individuals is limited as it requires a much larger sample than conventional rsfMRI scans. Thus, this study proposes an empirical Bayes estimation of individual pMEM using the variational expectation-maximization algorithm (VEM-MEM).

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Although prime editing is a promising genome editing method, the efficiency of prime editor 2 (PE2) is often insufficient. Here we generate a more efficient variant of PE2, named hyPE2, by adding the Rad51 DNA-binding domain. When tested at endogenous sites, hyPE2 shows a median of 1.

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The pairwise maximum entropy model (MEM) for resting state functional MRI (rsfMRI) has been used to generate energy landscape of brain states and to explore nonlinear brain state dynamics. Researches using MEM, however, has mostly been restricted to fixed-effect group-level analyses, using concatenated time series across individuals, due to the need for large samples in the parameter estimation of MEM. To mitigate the small sample problem in analyzing energy landscapes for individuals, we propose a Bayesian estimation of individual MEM using variational Bayes approximation (BMEM).

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Multilateration tracking systems (MLTSs) are used in industrial three-dimensional (3D) coordinate measuring applications. For high-precision measurement, system parameters must be calibrated properly in advance. For an MLTS using absolute distance measurement (ADM), the conventional self-calibration method significantly reduces estimation efficiency because all system parameters are estimated simultaneously using a complicated residual function.

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Ultrashort pulse lasers are emerging as an advanced tool of distance measurement, with their unique temporal and spectral characteristics being extended to diverse principles of absolute ranging and instrumentation. Here, a systematic methodology is presented for absolute ranging by means of the time-of-flight measurement of ultrashort light pulses using dual-comb asynchronous optical sampling. Based on an elaborate uncertainty analysis, influencing system parameters such as the pulse duration, repetition rate, and averaging time are optimized to achieve a sub-µm measurement accuracy.

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In this study, we have investigated the recycling of flexible polyurethane foam (PUF) using an ultrasonic reactor. Waste PUF of automotive seat cushions were subjected to ultrasonic horn oscillation of various amplitudes at different flow rate. Successful decrosslinking of ultrasonically treated waste PUF was confirmed by thorough characterizations such as gel fraction, crosslink density, and thermal property.

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Inspired by the epidermis-dermis composition of human skin, here we have simply developed a lightweight, robust, flexible, and biocompatible single-electrode triboelectric nanogenerator (S-TENG)-based prototype of bilayer artificial skin, by attaching one induction electrode with unfoamed skin layer of microcellular thermoplastic polyurethane (TPU) foam, which shows high-performance object manipulation [by responding differently toward different objects, viz., aluminum foil, balloon, cotton glove, human finger, glass, rubber glove, artificial leather, polyimide, poly(tetrafluoroethylene) (PTFE), paper, and wood], due to electrification and electrostatic induction during contact with the objects having different chemical functionalities. Comparative foaming behavior of ecofriendly supercritical fluids, viz.

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Growth impairment (GI) is one of the adverse effects of dexamethasone (DXM), and growth hormone (GH) has been used clinically to improve GI. The present study aimed to evaluate the manner in which DXM disturbs the growth rate of longitudinal bones, and the recovery effects of GH on DXM-induced GI in the longitudinal bones of adolescent male rats. In the first experiment, DXM (0, 0.

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Recent understanding that the brain at rest does not remain in a single state but transiently visits multiple states emphasizes the importance of state changes embedded in the brain network. Due to the effectiveness of larger networks in characterizing brain states, there is an increasing need for a network-based change point detection method that is applicable to large-size networks, particularly those with longer time series. This paper presents a fast and efficient method for detecting change points in the large-size functional networks of resting-state fMRI.

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We report a method of calculating the motion error of a linear motion bearing stage. The transfer function method, which exploits reaction forces of individual bearings, is effective for estimating motion errors; however, it requires the rail-form errors. This is not suitable for a linear motion bearing stage because obtaining the rail-form errors is not straightforward.

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In order to enhance the electron transport on the photoelectrodes of dye-sensitized solar cells, one-dimensional rutile nanorods were prepared using electrospun TiO2 nanofibers. The grain size of the nanorods increased with increasing temperature. Electrochemical impedance spectroscopy measurements revealed reduced interface resistance of the cells with the one-dimensional rutile nanorods due to the improved electron transport and the enhanced electrolyte penetration.

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Despite the widespread view of the brain as a large complex network, the dynamicity of the brain network over the course of a day has yet to be explored. To investigate whether the spontaneous human brain network maintains long-term stability throughout a day, we evaluated the intra-class correlation coefficient (ICC) of results from an independent component analysis (ICA), seed correlation analysis, and graph-theoretical analysis of resting state functional MRI, acquired from 12 young adults at three-hour intervals over 24 consecutive hours. According to the ICC of the usage strength of the independent network component defined by the root mean square of the temporal weights of the network components, the default mode network centered at the posterior cingulate cortex and precuneus, the superior parietal, and secondary motor networks showed a high temporal stability throughout the day (ICC>0.

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In this study, we used a bacteriophage λQ⁻S⁻ mutant that increased the stability of recombinant Escherichia coli during continuous culture. The operation was conducted in two stages: the first stage was carried out to promote cell growth, and the second stage was performed for product formation. The productivity of recombinant proteins depends on the substrate concentration of the fresh medium supplied to the second stage (S₃) and dilution rate of the second stage (D₂).

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Fiber tractography, a unique and non-invasive method to estimate axonal fibers within white matter, constructs the putative streamlines from diffusion tensor MRI by interconnecting voxels according to the propagation direction defined by the diffusion tensor. This direction has uncertainties due to the properties of underlying fiber bundles, neighboring structures and image noise. Therefore, robust estimation of the diffusion direction is essential to reconstruct reliable fiber pathways.

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The purposes of this study were to examine the effect of sensitivity encoding (SENSE) factors on cortical thickness measurements and to determine which SENSE factor to use to reliably measure cortical thickness in 3.0 T and 1.5 T T1-weighted MRI images.

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The neural reorganization of the visual cortex of early blind individuals was evaluated using voxel-by-voxel analysis of diffusion tensor images with regard to the diffusion direction, diffusion anisotropy and diffusivity. Reduced anisotropy and increased diffusivity was found mainly in the visual pathways of 18 early blind individuals as opposed to 25 sighted individuals. Alteration of the diffusion direction was detected not only in the visual pathways but also in nonvisual pathways such as the u fibers of the parietal lobe, the sagittal striatum, the pulvinar and the inferior and superior longitudinal fasciculi.

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We discuss two ways to use femtosecond pulsed lasers as a new interferometric light source for enhanced precision surface-profile metrology. First, a train of ultrafast laser pulses yields repeated low temporal coherence, which allows unequal-path scanning interferometry, which is not feasible with white light, to be performed. Second, the high spatial coherence of femtosecond pulsed lasers enables large-sized optics to be tested in nonsymmetric configurations with relatively small-sized reference surfaces.

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A two-stage continuous culture of Escherichia coli in combination with a bacteriophage lambda system was performed in order to overcome the intrinsic plasmid instability that is frequently observed in recombinant fermentation. A phage lambda vector with a Q(-) mutation was used to enhance the expression of the lambda system. The optimal values of the important operational variables such as the substrate concentration, the dilution rate, and the mean residence time on the expression of the cloned gene were determined in both batch and continuous cultures.

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