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Intestinal Peyer's Patches: Structure, Function, and In Vitro Modeling
No full textBackgound:Considering the important role of the Peyer's patches (PPs) in gut immune balance, understanding of the detailed mechanisms that control and regulate the antigens in PPs can facilitate the development of immune therapeutic strategies against the gut inflammatory diseases.Methods:In this review, we summarize the unique structure and function of intestinal PPs and current technologies to establish in vitro intestinal PP system focusing on M cell within the follicle-associated epithelium and IgA(+) B cell models for studying mucosal immune networks. Furthermore, multidisciplinary approaches to establish more physiologically relevant PP model were proposed.Results:PPs are surrounded by follicle-associated epithelium containing microfold (M) cells, which serve as special gateways for luminal antigen transport across the gut epithelium. The transported antigens are processed by immune cells within PPs and then, antigen-specific mucosal immune response or mucosal tolerance is initiated, depending on the response of underlying mucosal immune cells. So far, there is no high fidelity (patho)physiological model of PPs; however, there have been several efforts to recapitulate the key steps of mucosal immunity in PPs such as antigen transport through M cells and mucosal IgA responses.Conclusion:Current in vitro PP models are not sufficient to recapitulate how mucosal immune system works in PPs. Advanced three-dimensional cell culture technologies would enable to recapitulate the function of PPs, and bridge the gap between animal models and human
Controlling the formation energy of perovskite phase via surface polarity of substrate for efficient pure-blue light-emitting diodes
No full textQuasi-two-dimensional (quasi-2D) perovskites are composed of self-organized multiple-quantum-well structures. Imbalanced crystallization during the solution-processed deposition results in the formation of different 2D phases, which are affected by the surface polarity of substrates. Herein, we investigate the influence of the surface polarity of the underlying hole injection layer (HIL) on the crystallization dynamics of each 2D phase and the luminescence properties of resulting quasi-2D perovskite films. Incorporating L-dopa involving hydroxyl groups into the HIL gives the substrate a higher surface polarity, allowing the decrease in the critical free energy of nucleation. This HIL ensures the formation of dense nuclei involving a small-sized nucleus, which enables the quasi-2D perovskite film to entail a lower-n-dominated phase distribution. The modulated phase distribution eventually induces a hypsochromically shifted luminescence spectrum. Furthermore, by controlling the ratio of L-phenylalanine and L-dopa, efficient perovskite light-emitting diodes (PeLEDs) having well-matched electronic structure and pure-blue perovskite emitter are realized with a maximum external quantum efficiency of 5.57% at 472 nm. This work provides a facile approach to achieving efficient pure-blue PeLEDs
Effects of decay heat and cooling condition on the reactor pool natural circulation under RVACS operation in a water 2-D slab model
No full textThe temperature distribution of the reactor pool under natural circulation induced by the RVACS oper-ation was experimentally studied. According to the Bo' based similarity law, which could reproduce the temperature distribution of the working fluid under natural circulation, SINCRO-2D facility was designed based on the PGSFR. It was reduced to 1 : 25 in length scale, having water as a simulant of the sodium, which is the original working fluid. In general, temperature was stratified, however, effect of the natural circulation flow could be observed by the entrainment of the stratified temperature. Relative cooling contribution of the upper plenum (narrow gap) and lower plenum was approximately 0.2 and 0.8, respectively. In the range of decay heat from 0.2% to 1.0%, only the magnitude of the temperature was changed, while the normalized temperature maintained. Boundary temperature distribution change made a global temperature offset of the pool, without a significant local change. Therefore, the decay heat and cooling boundary condition had no significant effect on temperature distribution characteristics of the pool within the given range of the decay heat and boundary temperature distribution.(c) 2023 Korean Nuclear Society, Published by Elsevier Korea LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Perovskite solar cells approaching 25% PCE using side chain terminated hole transport materials with low concentration in a non-halogenated solvent process
No full textSynchronously achieving high power conversion efficiency (PCE) at low cost is a great challenge for the star hole transport material (HTM) spiro-OMeTAD-based perovskite solar cells (PSCs) because of their expense. Three side-chain modified HTMs, spiro-mF-V, -A, and -P, are designed and synthesized. The incorporation of side chains, such as vinyloxy, allyloxy, and propargyloxy, effectively improves the hole mobility and matches the energy levels with the perovskite layer. All three HTMs show a high PCE of 23.7, 23.80, and 24.85% for spiro-mF-V, -A, and -P using a non-halogenated solvent, such as toluene for eco-friendly PSC fabrication. Furthermore, spiro-mF-V, -A, and -P exhibit good solubility and homogeneous film with smooth surface morphologies in a non-halogenated solvent system. In particular, the obtained PCE values exceed 23.7% at a low concentration in a non-halogenated system, which is one-third that of the spiro-OMeTAD-based PSCs. To the best of the authors' knowledge, it is the highest reported PCE for HTMs using non-halogenated solvents in PSCs. These findings show that the side chain engineering technique can produce novel HTMs for low-cost, environmentally friendly solvent processing
Cortical representation of musical pitch in event-related potentials
No full textNeural coding of auditory stimulus frequency is well-documented; however, the cortical signals and perceptual correlates of pitch have not yet been comprehensively investigated. This study examined the temporal patterns of event-related potentials (ERP) in response to single tones of pitch chroma, with an assumption that these patterns would be more prominent in musically-trained individuals than in non-musically-trained individuals. Participants with and without musical training (N = 20) were presented with seven notes on the C major scale (C4, D4, E4, F4, G4, A4, and B4), and whole-brain activities were recorded. A linear regression analysis between the ERP amplitude and the seven notes showed that the ERP amplitude increased or decreased as the frequency of the pitch increased. Remarkably, these linear correlations were anti-symmetric between the hemispheres. Specifically, we found that ERP amplitudes of the left and right frontotemporal areas decreased and increased, respectively, as the pitch frequency increased. Although linear slopes were significant in both groups, the musically-trained group exhibited marginally steeper slope, and their ERP amplitudes were most discriminant for frequency of tone of pitch at earlier latency than in the non-musically-trained group (similar to 460 ms vs similar to 630 ms after stimulus onset). Thus, the ERP amplitudes in frontotemporal areas varied according to the pitch frequency, with the musically-trained participants demonstrating a wider range of amplitudes and inter-hemispheric anti-symmetric patterns. Our findings may provide new insights on cortical processing of musical pitch, revealing anti-symmetric processing of musical pitch between hemispheres, which appears to be more pronounced in musically-trained people
Photosensitive ion channels in layered MXene membranes modified with plasmonic gold nanostars and cellulose nanofibers
No full textArtificial ion channels are in demand for ionotronic devices. Here, the authors use layered MXene membranes modified with plasmonic gold nanostars and cellulose nanofibers to convert a thermal gradient into an ion current for photosensitive ion channeling. Ion channels transduce external stimuli into ion-transport-mediated signaling, which has received considerable attention in diverse fields such as sensors, energy harvesting devices, and desalination membrane. In this work, we present a photosensitive ion channel based on plasmonic gold nanostars (AuNSs) and cellulose nanofibers (CNFs) embedded in layered MXene nanosheets. The MXene/AuNS/CNF (MAC) membrane provides subnanometer-sized ionic pathways for light-sensitive cationic flow. When the MAC nanochannel is exposed to NIR light, a photothermal gradient is formed, which induces directional photothermo-osmotic flow of nanoconfined electrolyte against the thermal gradient and produces a net ionic current. MAC membrane exhibits enhanced photothermal current compared with pristine MXene, which is attributed to the combined photothermal effects of plasmonic AuNSs and MXene and the widened interspacing of the MAC composite via the hydrophilic nanofibrils. The MAC composite membranes are envisioned to be applied in flexible ionic channels with ionogels and light-controlled ionic circuits
Hand gesture recognition with out-of-distribution gesture detection using a soft sensor embedded glove
No full textHand gesture recognition has been applied to many applications, such as sign language translation and virtual reality. Soft sensor embedded gloves have been widely used to collect gesture data for hand gesture recognition. Using a soft sensor embedded glove has an advantage compared to vision-based approaches, because it is less affected by the environment and is not restricted to the angle of camera sensors, especially when it is applied to virtual reality industry. One of the existing challenges in machine learning-based hand gesture recognition is that new gestures, which are not seen in the training stage, are often discovered in the testing stage. In order to overcome this challenge, in this work, a hand gesture recognition model is proposed based on one-dimensional convolutional neural networks (1D CNN) and long short-term memory (LSTM) as well as a clustering method. In particular, a clustering method is used to detect out-of-distribution gestures, which are not contained in the clusters that are consisted of hand gestures used in the training stage. The experiment results validate that the proposed hand gesture recognition model performs better than existing hand gesture recognition methods and a proposed clustering methods detects out-of-distribution gestures with high accuracy
Molecularly engineered linear organic carbonates as practically viable nonflammable electrolytes for safe Li-ion batteries
No full text<jats:p>Concurrent modification of linear carbonates combining alkyl-chain extension and alkoxy substitution enables thermally stable high-performance batteries by decreasing volatility and increasing solvation ability simultaneously.</jats:p>
Design of Topology???Controlled Polyethers toward Robust Cooperative Hydrogen Bonding
No full textTopology control of polymers is critical for determining their physical properties and potential applications; in particular, topologies that incorporate numerous hydrogen bonding (H-bonding) donors and acceptors along the polymer chains considerably influence the formation of different inter- and intramolecular H-bonding motifs. In this study, the high-level control of inter- and intramolecular H-bonding is investigated in topology-controlled poly(glycidoxy carbonyl benzoic acid)s (PGCs). Three types of topology-controlled PGCs (i.e., linear, hyperbranched, and branched cyclic structures having a similar degree of polymerization) are prepared by introducing aromatic carboxylic acids into the corresponding polyglycidols (PGs) via quantitative post-polymerization modification with phthalic anhydride. The obtained three types of PGCs demonstrated the high-level interplay between the inter- and intramolecular H-bonding in polymer chains by exhibiting the pH-dependent self-association properties in the solution state and the strong adhesion properties in the bulk state with high transparency. Interestingly, the dramatically enhanced adhesive property by 2.6-fold is demonstrated by simple mixing of branched cyclic PGC and topology-controlled PGs to promote the cooperative H-bonding between polymer chains. The new class of cooperative H-bonding is anticipated between topology-controlled polymers to contribute to the development of advanced adhesive and the high potential in biological and biomedical applications due to its excellent biocompatibility
????????? ??????????????? ?????? Ti3C2Tx MXene??? ????????? ???????????? ??????
No full textMXene is one of the most fascinating 2D materials owing to its great electrical properties and unique performance. Among various application areas, the performance of organic material adsorption has been highlighted with the growing interest in the biocompatible applications of MXene. Although previous research revealed that the huge surface area of this 2D nanomaterial could lead to superior organic material adsorption performance, surface functional groups were usually controlled by changing the pH, and the MXene was generally produced by HF etchant. In this study, a surface modification method of Ti3C2Tx MXene film was proposed to enhance organic material adsorption by irradiating the pulsed plasma electron beam (EB). Methylene blue (MB)-dispersed DI water was prepared, and pristine MXene was prepared at pH 7. The MB concentration was only reduced by 20% by pristine MXene. However, EB-treated MXene adsorbed about 75% of the MB within 20 min and over 90% within 80 min when the MXene film was ground to powder form. The results showed that the increased surface area and formation of hydrophilic functional groups successfully modified MB adsorption following EB irradiation under optimal processing conditions