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Cardiac Electrophysiological Effects of Light-Activated Chloride Channels
摘要： During the last decade, optogenetics has emerged as a paradigm-shifting technique to monitor and steer the behavior of specific cell types in excitable tissues, including the heart. Activation of cation-conducting channelrhodopsins (ChR) leads to membrane depolarization, allowing one to effectively trigger action potentials (AP) in cardiomyocytes. In contrast, the quest for optogenetic tools for hyperpolarization-induced inhibition of AP generation has remained challenging. The green-light activated ChR from Guillardia theta (GtACR1) mediates Cl?-driven photocurrents that have been shown to silence AP generation in different types of neurons. It has been suggested, therefore, to be a suitable tool for inhibition of cardiomyocyte activity. Using single-cell electrophysiological recordings and contraction tracking, as well as intracellular microelectrode recordings and in vivo optical recordings of whole hearts, we find that GtACR1 activation by prolonged illumination arrests cardiac cells in a depolarized state, thus inhibiting re-excitation. In line with this, GtACR1 activation by transient light pulses elicits AP in rabbit isolated cardiomyocytes and in spontaneously beating intact hearts of zebrafish. Our results show that GtACR1 inhibition of AP generation is caused by cell depolarization. While this does not address the need for optogenetic silencing through physiological means (i.e., hyperpolarization), GtACR1 is a potentially attractive tool for activating cardiomyocytes by transient light-induced depolarization.
关键词： heart,action potential,zebrafish,optogenetics,GtACR1,natural anion channelrhodopsin
更新于2025-09-23 15:22:29
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Formation of zirconia precursor nanoplates mediated by ionic liquid and transformation to monoclinic ZrO <sub/>2</sub> nanostructures
摘要： The [Zr(OH)5]– imidazolium complex was used to synthesize a zirconia precursor with plate-like nanostructure hydrolyzed under strong acid conditions, which was characterized by means of powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis, inductively coupled plasma and electronic differential system. The zirconia precursor can be transformed to monoclinic ZrO2 by annealing at a temperature above 400 °C. With the increasing of the curing temperature, it tended to give rise to porous ZrO2 nanostructures.
关键词： Zirconia precursor,Zirconium oxide,Anion exchange reaction,Nanoplate,Ionic liquid
更新于2025-09-23 15:22:29
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Growth and physical properties of Ce(O,F)Sb(S,Se)2 single crystals with site-selected chalcogen atoms
摘要： Ce(O,F)Sb(S,Se)2 single crystals were successfully grown using a CsCl/KCl ?ux method. The obtained crystals have a plate-like shape with the typical size of 1–2 mm and well-developed ab-plane, which enables X-ray single crystal structural analysis. The Ce(O,F)Sb(S,Se)2 crystallizes in a monoclinic space group, P21/m, with lattice parameters of a = 4.121(7) ?, b = 4.109(7) ?, c = 13.233(15) ?, β = 97.94(7) °. It is composed of alternate stacking of Ce-(O,F) and Sb-SSe layers, and the Sb-SSe layer includes selective occupation of Se atoms in its in-plane site. The valence state of Ce is estimated to be Ce3+ by X-ray absorption ?ne spectroscopy analysis. The single crystals show an insulating behavior, and a magnetic ordering around 6 K.
关键词： E. Photoemission spectroscopy,B. Flux growth,D. Topological insulator,A. Layered mixed-anion compounds
更新于2025-09-23 15:22:29
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Discovery and Characterization of a Naturally Occurring, Turn-On Yellow Fluorescent Protein Sensor for Chloride
摘要： Fluorescent proteins have been extensively engineered and applied as optical indicators for chloride in a variety of biological contexts. Surprisingly, given the biodiversity of ?uorescent proteins, a naturally occurring chloride sensor has not been reported to date. Here, we present the identi?cation and spectroscopic characterization of the yellow ?uorescent protein from the jelly?sh Phialidium sp. (phiYFP), a rare example of a naturally occurring, excitation ratiometric, and turn-on ?uorescent protein sensor for chloride. Our results show that chloride binding tunes the pKa of the chromophore Y66 and shifts the equilibrium from the ?uorescent phenolate form to the weakly ?uorescent phenol form. The latter likely undergoes excited-state proton transfer to generate a turn-on ?uorescence response that is pH-dependent. Moreover, anion selectivity and mutagenesis in the chloride binding pocket provide additional evidence for the proposed chloride sensing mechanism. Given these properties, we anticipate that phiYFP, with further engineering, could be a new tool for imaging cellular chloride dynamics.
关键词： phiYFP,mutagenesis,chloride sensor,anion selectivity,turn-on fluorescence,pH-dependent,excitation ratiometric,fluorescent proteins
更新于2025-09-23 15:21:21
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Photoelectron Spectroscopy of Molecular Anion of Alq <sub/>3</sub> : An Estimation of Reorganization Energy for Electron Transport in the Bulk
摘要： A molecular anion of tris(8-hydroxyquinolinato)aluminum (Alq3) was generated by a pulsed discharge to the solid sample under supersonic expansion and its photoelectron spectrum was recorded after mass selection. The vertical detachment energy of Alq3? and the adiabatic electron affinity of Alq3 were determined to be 1.24 ± 0.01 and 0.89 ± 0.04 eV, respectively. By using these energies determined for monomeric Alq3, the reorganization energy for the intermolecular electron transport in bulk Alq3 was estimated to be 0.70 ± 0.08 eV.
关键词： Photoelectron Spectroscopy,Electron Transport,Reorganization Energy,Alq3,Molecular Anion
更新于2025-09-23 15:21:21
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Bright Blue Light Emission of Ni2+ ions doped CsPbClxBr3-x Perovskite Quantum Dots Enabling Efficient Light-Emitting Devices
摘要： In recent years, significant advances have been achieved in the red and green perovskite quantum dots（PQDs）based light-emitting diodes (LEDs). However, the performances of the blue perovskite LEDs are still seriously lagging behind that of the green and red counterparts. Herein, we successfully developed Ni2+ ions doped CsPbClxBr3-x PQDs through the room-temperature supersaturated recrystallization synthetic approach. We simultaneously realized the doping of various concentrations of Ni2+ cations, and modulated the Cl/Br element ratios through introducing different amount of NiCl2 solution in the reaction medium. By the synthetic method, not only the emission wavelength from 508 to 432 nm of Ni2+ ions doped CsPbClxBr3-x QDs was facially adjusted, but also the photoluminescence quantum yield (PLQY) of PQDs was greatly improved due to efficiently removing the defects of the PQDs. Thus, the blue emission at 470 nm with PLQY of 89% was achieved in 2.5% Ni2+ ions doped CsPbCl0.99Br2.01 QDs, which increased nearly three times over that of undoped CsPbClBr2 QDs, and was the highest for the CsPbX3 PQDs with blue emission that fulfilling the NTSC standards. Benefiting from the high luminous Ni2+ ions doped PQDs, the blue emitting LED at 470 nm was obtained, exhibiting an external quantum efficiency (EQE) of 2.4% and a maximum luminance of 612 cd/m2, which surpassed the best performance reported previously for the corresponding blue-emitting PQDs based LED.
关键词： perovskite QD-LEDs,Ni2+ ion doping,blue emission,anion exchange,perovskite quantum dots
更新于2025-09-23 15:21:01
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Efficient, stable silicon tandem cells enabled by anion-engineered wide-bandgap perovskites
摘要： Maximizing the power conversion efficiency (PCE) of perovskite-silicon tandem solar cells that can exceed the Shockley-Queisser single-cell limit requires a high performing, stable perovskite top cell with a wide band gap. We developed a stable perovskite solar cell with a band gap of ~1.7 electron volt that retained over 80% of its initial PCE of 20.7% after 1000 hours of continuous illumination. Anion engineering of phenethylammonium (PEA)-based two-dimensional (2D) additives was critical for controlling the structural and electrical properties of 2D passivation layers based on a PbI2-framework. The high PCE of 26.7% of a monolithic two-terminal wide gap perovskite/Si tandem solar cell was made possible by the ideal combination of spectral responses of the top and bottom cells.
关键词： tandem solar cells,anion engineering,perovskite,silicon,wide-bandgap
更新于2025-09-23 15:21:01
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The near-infrared fluorescent dye IR-780 was coupled with cabazitaxel for castration-resistant prostate cancer imaging and therapy
摘要： A new drug, Caba-780, was synthesized by chemical coupling of the heptamethyl phthalocyanine near-infrared fluorescent (NIRF) dye IR-780 and the paclitaxel-based chemotherapeutic drug cabazitaxel. Then, the potential value of Caba-780 in the diagnosis and treatment of castration-resistant prostate cancer (CRPC) was evaluated. The CRPC cell lines DU145 and PC-3, as well as the normal human prostate stromal cell line WPMY-1, were used to evaluate the uptake of Caba-780 and its antitumor effect in vitro. The distribution, antitumor effect, and safety of Caba-780 were also evaluated in tumor-bearing mouse xenograft models. Our results showed that Caba-780 was efficiently absorbed by DU145 and PC-3 cells and that the cytotoxicity of Caba-780 was significantly stronger than that of IR-780 and cabazitaxel. In addition, Caba-780 inhibited the migration and invasion of DU145 and PC-3 cells and promoted apoptosis by prolonging the G2 phase of the cell cycle. Further analysis indicated that Caba-780 could be used to effectively image tumor xenografts. At the same time, this drug inhibited the growth of tumors in vivo. Therefore, the new synthetic drug Caba-780 has potential applications in the diagnosis and treatment of CRPC.
关键词： Organic anion-transporting polypeptide,Chemotherapy,Castration-resistant prostate cancer,Near-infrared fluorescent dye
更新于2025-09-23 15:21:01
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Slow photoelectron velocity-map imaging of cold C7? and C9?
摘要： High-resolution anion photoelectron spectra of cryogenically cooled C7? and C9? clusters obtained using slow photoelectron velocity-map imaging are presented, providing insight into the vibronic structure of neutral C7 and C9. These spectra yield accurate measurements of vibrational frequencies for the neutral clusters as well as electron affinities of 3.3517(4) and 3.6766(14) eV for C7 and C9, respectively. In the C7? spectrum, transitions involving the previously unreported v1 and v2 symmetric stretching modes, as well as the v9, v10, and v11 asymmetric bending modes, are assigned. Spin–orbit splitting is observed for several transitions in this spectrum, giving an energy difference of 28(6) cm?1 between the 2Π1/2g and 2Π3/2g spin–orbit levels of the C7? anion. In the spectrum of C9?, transitions involving the previously unreported symmetric stretch v1 and the asymmetric bend v11 are observed. In both spectra, several features are assigned to Franck-Condon forbidden transitions involving the doubly degenerate v10 and v11 modes of C7 and the v13 and v14 modes of C9. The appearance of these transitions is attributed to Herzberg-Teller coupling between the electronic states of the neutral clusters. Additional FC-forbidden transitions to states previously observed in gas-phase infrared experiments are observed and attributed to vibronic coupling between the electronic states of the anion, resulting in non-totally symmetric character in the anion’s full vibrational ground state. Finally, consideration of the energy dependence of detachment cross sections and Dyson orbital analyses reveal that addition of more carbon atoms to the linear chain results in photodetachment from delocalized molecular orbitals with increasing nodal structure, leading to threshold photodetachment cross sections that differ considerably from simple symmetry considerations.
关键词： Herzberg-Teller coupling,Franck-Condon forbidden transitions,anion photoelectron spectroscopy,vibronic structure,carbon clusters,slow photoelectron velocity-map imaging
更新于2025-09-23 15:21:01
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Intrinsic anion diffusivity in lead halide perovskites is facilitated by a soft lattice
摘要： Facile ionic transport in lead halide perovskites plays a critical role in device performance. Understanding the microscopic origins of high ionic conductivities has been complicated by indirect measurements and sample microstructural heterogeneities. Here, we report the direct visualization of halide anion interdiffusion in CsPbCl3–CsPbBr3 single crystalline perovskite nanowire heterojunctions using wide-field and confocal photoluminescence measurements. The combination of nanoscale imaging techniques with these single crystalline materials allows us to measure intrinsic anionic lattice diffusivities, free from complications of microscale inhomogeneity. Halide diffusivities were found to be between 10?13 and ～10?12 cm2/second at about 100 °C, which are several orders of magnitudes lower than those reported in polycrystalline thin films. Spatially resolved photoluminescence lifetimes and surface potential measurements provide evidence of the central role of halide vacancies in facilitating ionic diffusion. Vacancy formation free energies computed from molecular simulation are small due to the easily deformable perovskite lattice, accounting for the high equilibrium vacancy concentration. Furthermore, molecular simulations suggest that ionic motion is facilitated by low-frequency lattice modes, resulting in low activation barriers for vacancy-mediated transport. This work elucidates the intrinsic solid-state ion diffusion mechanisms in this class of semisoft materials and offers guidelines for engineering materials with long-term stability in functional devices.
关键词： anion diffusivity,nanoscale imaging,molecular simulation,halide perovskite nanowire,soft lattice
更新于2025-09-23 15:21:01