Barnacles are unique marine sessile crustaceans and permanently attach to various foreign surfaces during most of their lifespan. The protein complex secreted from their body and used to attach their ...calcareous shell to almost all surfaces in water has long fascinated us because we have limited technology with which to attach materials in water. Unraveling the mechanism of underwater attachment by barnacles is thus important for interface science, for the understanding of the biology and physiology of barnacles, and for the development of technology to prevent fouling. Previous studies have indicated that the intermolecular interactions optimized by conformations of the adhesive proteins are crucial in the self-assembly and/or curing of the adhesive. This study aimed to identify the possible structural determinants responsible for the self-assembly. Thioflavin T binding screening of peptides designed on the basis of the primary structure of a bulk 52 kDa cement protein indicated the presence of some amyloidogenic motifs in the protein. The conformation of the peptide was transformed to a β-sheet by an increase in either pH or ionic strength, resulting in its self-assembly. Thioflavin T binding was inhibited by small polyphenolic molecules, suggesting the contribution of aromatic interactions during self-assembly. The occurrence of amyloid-like units in the protein implies that the protein conformation is an important factor contributing to the self-assembly of the cement, the first event of the curing, as the adhesive material is secreted into the seawater out of the animal's body.
Selective unipolarization of an ambipolar polymer semiconductor, PNDTI‐BT, by using different self‐assembled monolayers, is demonstrated. For p‐unipolarization, ...1H,1H,2H,2H‐perfluorodecyltriethoxysilane is most effective, whereas for n‐unipolarization, 3‐(N, N′‐dimethylamino)propyltriethoxysilane is the best. Using these selective unipolarization effects, the complementary inverters based on the ambipolar polymer fabricated by a simple solution process show greatly improved switching behaviors with low power consumption.
•Based upon the analysis of several molecular systems, the design strategy for molecules for high-mobility organic semiconductors are discussed.•Correlation between molecular/packing structures and ...electronic structures in the solid state for representative high-mobility organic semiconductors are presented.•Several different molecular factors that can be controlled are proposed for realizing high-mobility organic semiconductors.
In this article, we focus on several high-mobility organic semiconductors so far reported, such as acenes, heteroacenes, and rylene diimides, in order to extract molecular and supramolecular factors, including molecular size, manner of π-extension, heteroatom, molecular shape, and substituent, which would enhance our understanding of the design strategy for the synthesis of molecules for high field-effect-mobility semiconductors. After performing a detailed inspection of these organic semiconductors, we arrive at the conclusion that the construction of a two-dimensional (2D) electronic structure with large orbital overlaps in the solid state is the key. This can be realized by tuning these molecular factors; for example, the use of linearly π-extended systems with fused aromatic ring structures, heteroatom incorporation, and the use of suitable substituents for 2D packing, such as herringbone or 2D bricklayer packing.
Thermometers for monitoring cellular temperature Nakano, Masahiro; Nagai, Takeharu
Journal of photochemistry and photobiology. C, Photochemistry reviews,
March 2017, 2017-03-00, 20170301, Letnik:
30
Journal Article
Recenzirano
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•Various kinds of thermometers for monitoring cellular temperature have been developed.•Some thermometers showed heterogeneous temperature distribution and thermogenesis at the ...single-cell level.•There is a discussion on the reliability of fluorescence-based thermometric methods.
Temperature is a critical parameter that influences various biological events and reactions in homeotherms (including mammals), poikilotherms, and plants. However, the spatiotemporal patterns of temperature at the single-cell level remain largely unknown. Various kinds of thermometers have been developed for monitoring temperature at the single-cell level. We introduce some cellular thermometers based on Europium (III) thenoyltrifluoroacetonate trihydrate, gold nanoclusters, nanodiamonds, synthetic polymers, quantum dots, green fluorescent protein, and bimaterial microcantilevers. We also discuss a critique of these thermometric methods and provide some responses to this critique.
Temperature is a fundamental physical parameter that plays an important role in biological reactions and events. Although thermometers developed previously have been used to investigate several ...important phenomena, such as heterogeneous temperature distribution in a single living cell and heat generation in mitochondria, the development of a thermometer with a sensitivity over a wide temperature range and rapid response is still desired to quantify temperature change in not only homeotherms but also poikilotherms from the cellular level to in vivo. To overcome the weaknesses of the conventional thermometers, such as a limitation of applicable species and a low temporal resolution, owing to the narrow temperature range of sensitivity and the thermometry method, respectively, we developed a genetically encoded ratiometric fluorescent temperature indicator, gTEMP, by using two fluorescent proteins with different temperature sensitivities. Our thermometric method enabled a fast tracking of the temperature change with a time resolution of 50 ms. We used this method to observe the spatiotemporal temperature change between the cytoplasm and nucleus in cells, and quantified thermogenesis from the mitochondria matrix in a single living cell after stimulation with carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, which was an uncoupler of oxidative phosphorylation. Moreover, exploiting the wide temperature range of sensitivity from 5°C to 50°C of gTEMP, we monitored the temperature in a living medaka embryo for 15 hours and showed the feasibility of in vivo thermometry in various living species.
CRISPR-based nucleic-acid detection is an emerging technology for molecular diagnostics. However, these methods generally require several hours and could cause amplification errors, due to the ...pre-amplification of target nucleic acids to enhance the detection sensitivity. Here, we developed a platform that allows "CRISPR-based amplification-free digital RNA detection (SATORI)", by combining CRISPR-Cas13-based RNA detection and microchamber-array technologies. SATORI detected single-stranded RNA targets with maximal sensitivity of ~10 fM in <5 min, with high specificity. Furthermore, the simultaneous use of multiple different guide RNAs enhanced the sensitivity, thereby enabling the detection of the SARS-CoV-2 N-gene RNA at ~5 fM levels. Therefore, we hope SATORI will serve as a powerful class of accurate and rapid diagnostics.
Engineered fluorescent protein (FP) chimeras that modulate their fluorescence in response to changes in calcium ion (Ca²⁺) concentration are powerful tools for visualizing intracellular signaling ...activity. However, despite a decade of availability, the palette of single FP-based Ca²⁺ indicators has remained limited to a single green hue. We have expanded this palette by developing blue, improved green, and red intensiometric indicators, as well as an emission ratiometric indicator with an 11,000% ratio change. This series enables improved single-color Ca²⁺ imaging in neurons and transgenic Caenorhabditis elegans. In HeLa cells, Ca²⁺ was imaged in three subcellular compartments, and, in conjunction with a cyan FP—yellow FP—based indicator, Ca²⁺ and adenosine 5′-triphosphate were simultaneously imaged. This palette of indicators paints the way to a colorful new era of Ca²⁺ imaging.
Background: Antithrombotic therapy after left atrial appendage closure (LAAC) in patients at high risk of bleeding remains controversial. We present real-world clinical outcomes of LAAC.Methods and ...Results: Data from 74 consecutive patients who received LAAC therapy between January 2020 and June 2022 were analyzed. Patients received 1 of 3 antithrombotic therapies according to the bleeding risk category or clinical event. Regimen 1 was based on a prior study, regimen 2 comprised a lower antiplatelet drug dose without dual antiplatelet therapy, and regimen 3 was antiplatelet drug administration for as long as possible to patients with uncontrollable bleeding who were required to stop anticoagulant drugs. Overall, 73 (98.6%) procedures were successful. Of them, 16 (21.9%) patients were selected for regimen 1, 46 (63.0%) for regimen 2, and 11 (15.1%) for regimen 3. Device-related thrombosis (13% vs. 0% vs. 0%, P=0.0257) only occurred with regimen 1. There was no difference in major bleeding event rates (6% vs. 2% vs. 9%, P=0.53).Conclusions: The post-LAAC antithrombotic regimen was modified without major concerns.
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•Ionic liquids (ILs) aided-device engineering champions is widely reviewed.•The role of ILs in the production of high-quality perovskite film is discussed.•ILs can potentially improve ...the long-term stability of perovskite solar cells.•ILs represents a significant step toward reliable perovskite PV technology.
The efficiency of perovskite solar cells (PSCs) is rapidly increasing, so that their long-term operational stability has become a major focus for commercialization and market adoption. The development of novel strategies and materials to improve the stability of small and large solar modules without compromising power conversion efficiency (PCE) is an ongoing challenge. Ionic liquids (ILs) are emerging as useful additives, solvents, and charge transport materials for the preparation of highly efficient perovskite films. Perovskite crystallizes slowly in ILs to form large and uniform grains, and PSCs fabricated with high-quality perovskite films are efficient and stable. Herein we review recently developed systemic device engineering, and we discuss the impact of ILs in the production of highly efficient and stable PSCs. This review is intended to serve as a guide to develop highly crystalline perovskite films with larger grains and more homogeneous morphologies, all of which contribute to enhancing the stability of PSC performance. Recent progress in the use of ILs as solvents and additives for PSCs is a significant step toward developing reliable perovskite photovoltaic devices. Finally, we discuss challenges and future research directions for the fabrication of efficient and stable PSCs.
Intracellular Ca(2+) levels play a crucial role in the control of ATP synthesis. However, the spatiotemporal correlation between ATP and Ca(2+) remains unclear due to the inability to visualize these ...factors within same individual cells. A Förster resonance energy transfer (FRET)-based fluorescent ATP probe, named ATeam, was recently developed for ATP imaging in single living cells. However, the spectra of cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) used as the FRET donor and the acceptor, respectively, significantly overlap with the ultraviolet-excitable Ca(2+) probe, fura-2. In the present work, we developed new red-shifted ATP probes, GO-ATeams, in which green fluorescent protein (GFP) and orange fluorescent protein (OFP) was used as the FRET pair to minimize spectral overlap with the fura-2 emission. The dynamics of intracellular Ca(2+) and mitochondrial ATP levels in single histamine-stimulated HeLa cells were successfully visualized by using fura-2 and GO-ATeam. The experiments showed that histamine induced increases of both intracellular Ca(2+) and mitochondrial ATP levels. The increment of mitochondrial ATP levels was proportional to that of Ca(2+). This finding suggests that cellular Ca(2+) levels might precisely control mitochondrial ATP synthesis in response to the increased ATP consumption triggered by Ca(2+). In addition, GO-ATeam has several advantages over the original ATeam. The GO-ATeam signal was more stable against acidification, which would allow ATP imaging inside acidic intracellular compartments. Also, the GO-ATeam excitation wavelength is much less phototoxic to cells, making the probe suitable for long-time observation.
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