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On-off-on relay fluorescence recognition of ferric and fluoride ions based on indicator displacement in living cells
摘要： A new boronic acid derivative functionalized with a 4-(3-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-1,2,4-oxadiazol-5-yl)phenyl (IOP) moiety was synthesized for use as a sequential “on-off-on”-type relay fluorescence probe for Fe3+ ions and F? ions with high selectivity and sensitivity under physiological conditions. The introduction of Fe3+ to IOP boronic acid (IOPBA) formed an Fe3+-IOPBA complex, which led to quenching of the blue fluorescence intensity at 458 nm. The lowest-energy conformation of IOPBA was theoretically predicted to adopt an extended structure, and the Fe3+ ion in the Fe3+-IOPBA complex was coordinated to two phenyl groups to form a p-complex. Upon addition of F? to the Fe3+-IOPBA complex, the original fluorescence was recovered due to formation of [FeF6]3?, resulting in “on-off-on”-type sensor behavior. IOPBA showed high selectivity towards Fe3+ among other cations. Moreover, the Fe3+-IOPBA complex showed specific selectivity towards F?, with other cations and anions not interfering with detection. Both sensing processes showed 1:1 stoichiometry with binding constants of 6.87 × 106 and 4.49 × 106 mol–1 L for Fe3+ with IOPBA and F? with Fe3+-IOPBA, respectively. The limits of detection for Fe3+ and F? were 10 and 1 nM, respectively. The proposed method was successfully applied in real water samples. Furthermore, the probe had low cytotoxicity and was successfully used as a bioimaging reagent to detect intracellular Fe3+ and F? in living HeLa cells.
关键词： Fluorescence imaging,On-off-on sensor,Probe for Fe3+ ions and F? ions,Living HeLa cells,Boronic acid derivative
更新于2025-11-21 11:08:12
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Three-dimensional Nanoscale Mapping of Porosity in Solution-Processed ITO Multilayer Thin Films for Patternable Transparent Electrodes
摘要： Indium tin oxide (ITO) films constitute components of many layered heterostructures used for emergent technologies beyond conventional optoelectronics. Compositional and morphological changes have a direct impact on the device’s performance. Hence control over the morphology with advanced multimodal characterization approaches are required to evaluate the devices. Herein multilayer ITO films deposited by spin coating were quantified in nanoscale detail in three dimensions by combining results from depth-sensitive neutron reflectometry (NR), non-contact topographic AFM images and cross-sectional SEM images. Films with different number of deposited layers were visually transparent even though the topmost layer was as high as 60% porous, with porosity gradually decreasing as the number of the underneath sublayers increased. Surface and interfacial roughness through the total film and individual layer thickness were obtained. NR data also furnished quantitative depth information on the films chemical composition and layer-by-layer bulk density, which has never been obtained before, providing a way to monitor and ultimately control the sheet resistivity via the pore network. When the same formulation is used for inkjet printing patterns, the larger pores disappear and the optical properties are improved to >90% transmittance at all visible wavelengths. All 5L films achieved sheet resistivities as low as 10-2 ?-cm and can therefore be used as patternable transparent electrodes for many devices including liquid crystal displays.
关键词： thin multilayer film,neutron reflectometry,depth density distribution,neutron absorption reflectometry,Indium tin oxide,porosity,structure chemical depth profile,off-specular neutron scattering,layer by layer deposition
更新于2025-11-19 16:56:35
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Peptic Fluorescent “Signal-On” and “Signal-Off” Sensors Utilized for the Detection Protein Post-Translational Modifications
摘要： Protein post-translational modifications (PTMs) are typically enzyme-catalyzed events generating functional diversi?cation of proteome; thus, multiple PTM enzymes have been validated as potential drug targets. We have previously introduced energy-transfer-based signal-modulation method called quenching resonance energy transfer (QRET), and utilize it to monitor PTM addition or removal using the developed peptide-break technology. Now we have reinvented the QRET technology, and as a model, we introduced the tunable ?uorescent “signal-on” and “signal-o?” detection scheme in the peptide-break PTM detection. Taking the advantage of time-resolved ?uorescence-based single-label detection technology, we were able to select the signal direction upon PTM addition or removal by simply introducing di?erent soluble Eu3+-signal-modulating molecule. This enables the selection of positive signal change upon measurable event, without any additional labeling steps, changes in assay condition or Eu3+-reporter. The concept functionality was demonstrated with four Eu3+-signal modulators in a high-throughput compatible kinase and phosphatase assays using signal-on and signal-o? readout at 615 nm or time-resolved Fo?rster resonance energy transfer at 665 nm. Our data suggest that the introduced signal modulation methodology provides a transitional ?uorescence-based single-label detection concept not limited only to PTM detection.
关键词： time-resolved fluorescence,signal-off,high-throughput screening,peptide-break technology,protein post-translational modifications,FRET,signal-on
更新于2025-11-19 16:56:35
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Enzyme-free “on-off-on” photoelectrochemical biosensor based on cascaded quadratic amplification strategy for miRNA 141 detection
摘要： MicroRNAs (miRNAs) assay is of great significance for early diagnosis of diseases, so an enzyme-free “on-off-on” PEC biosensor has been developed for sensitive miRNA 141 determination. Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots (Mn:CdS@ZnS QDs) and manganese porphyrin (MnPP) have been used as photoelectric material and photosensitizer, respectively. And a high photocurrent of approximately 70.0 μA has been obtained. Cascaded quadratic amplification strategy has been applied in the system. Mn:CdS@ZnS QDs was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). Photoelectrochemical and electrochemical technologies were used to monitor the fabrication process of the biosensor. The sensing platform exhibits recommendable stability and good selectivity, miRNA 141 can be accurately quantified with a linear range of 1.00 × 10-14 to 1.00 × 10-8 mol·L-1 and the detection limit of 3.30 fmol·L-1. This method provides promising potential to explore sensitive detection models for various biological molecules.
关键词： Hybridization chain reaction,Catalytic hairpin assembly,Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots,MiRNA 141,Photoelectrochemistry,On-off-on
更新于2025-11-14 17:03:37
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TiO2-Coated Core-Shell Ag Nanowire Networks for Robust and Washable Flexible Transparent Electrodes
摘要： Silver nanowires (AgNWs) are the most promising materials to fabricate flexible transparent electrodes (FTEs) used in next-generation electronics. However, there are several bottlenecks for AgNWs-based FTEs to achieve large-scale applications, which are the thermal instability and rough surface topography of AgNWs and the poor interfacial adhesion between AgNWs and used substrate. To simultaneously address these aforementioned issues, a robust and washable FTE is prepared based on AgNW@TiO2 core-shell network embedding in polyimide (PI) substrate through a facile and scalable solution-based process. After treating with TiO2 sol, an ultra-thin, conformal, and continuous TiO2 shell is coated on AgNWs, which can effectively suppress the atomic surface diffusion. In comparison with pristine AgNW network that breaks into nanorods and nanospheres at 250 °C for 10 min, the AgNW@TiO2 core-shell network is stable at 300 °C, and its resistance just increases by a factor of 11 after annealing at 400 °C for 1 h. Furthermore, the TiO2 shell simultaneously increases the electrical and optical properties of AgNW network. After flowing PI precursors, drying, and thermally curing, the AgNW@TiO2 core-shell network is embedded on the surface of PI substrate with surface roughness of 1.9 nm. In addition to high thermal stability, the conductivity of the AgNWs@TiO2-PI composite FTE remains almost unchanged after repeated 3M tape peeling off cycles and mechanical bending cycles. It is also demonstrated that the AgNWs@TiO2-PI composite FTE is washable, and the relative change in resistance (?R/R0) is ~12% after 100 washing cycles in which a variety of stress situations occurring in combination.
关键词： flexible transparent electrodes,peeling off and mechanical stabilities,TiO2 sol,silver nanowire@TiO2 core-shell network,thermal and washing stabilities
更新于2025-11-14 14:32:36
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Normally-off AlGaN/GaN Heterojunction Metal-Insulator-Semiconductor Field-Effect Transistors with Gate-First Process
摘要： In this study, AlGaN/GaN heterojunction metal-insulator-semiconductor field-effect transistors with gate-first process were developed for normally-off operation with p-GaN cap layers and SiNx dielectrics. To avoid the effect of the annealing process on the gate, a low-temperature ohmic contact technique was developed at an annealing temperature of about 500 oC for 20 min in N2 ambient. With the assistance of inductively coupled plasma dry etching, a contact resistance of 1.45 Ω·mm and sheet resistance of 1080.1 Ω/□ were obtained in the recessed region. Owing to the inset of the SiNx layer, the threshold voltage of fabricated device was enhanced to approximately 2 V, and good pinch-off was observed with the gate voltage up to 16 V. Compared with the conventional high-temperature ohmic annealing process, the gate leakage current was suppressed significantly in both reverse and forward directions. Good device performance was confirmed with a maximum channel electron field-effect mobility of 1500 cm2V-1s-1.
关键词： low-temperature ohmic contact,normally-off,gate-first,metal-insulator-semiconductor,AlGaN/GaN HFET
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) - Sarajevo, Bosnia and Herzegovina (2018.10.21-2018.10.25)] 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) - Optimization of Anoff-Grid PV System in Respect to the Capacity Shortage Value
摘要： The main goal of this paper is to describe optimization of off-grid PV system in respect to the capacity shortage value remote area in Osijek. The paper shows a model consisting of PV modules, converter, batteries and electrical load. The examined data are based on measured load values for the residential home. Finding an optimal size of off-grid PV system is shown using HOMER software. The investment costs are presented regarding different values of capacity shortage ranging from 0 % to 10 %. This paper also presents the influence of O&M ranging from 0 % to 3 % on the NPC.
关键词： optimization,O&M,HOMER,off-grid PV,Capacity shortage
更新于2025-09-23 15:23:52
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Battery-assisted low-cost hydrogen production from solar energy: Rational target setting for future technology systems
摘要： The massive implementation of renewable energy requires sophisticated assessments considering the combination of feasible technology options. In this study, a techno-economic analysis was conducted for hydrogen production from photovoltaic power generation (PV) utilizing a battery-assisted electrolyzer. The installed capacity of each component technology was optimized for the wide range of unit costs of electricity from the PV, battery, and proton-exchange membrane electrolyzer. Leveling of PV output by battery, the necessary capacity of electrolyzer is suppressed and the operating ratio of electrolyzer increases. The battery-assist will result in a lower hydrogen production cost when the benefit associated with the smaller capacity and higher operation ratio of the electrolyzer exceeds the necessary investment for battery installation. The results from this study indicated the cost of hydrogen as low as 17 to 27 JPY/Nm3 using a combination of technologies and the achievement of ambitious individual cost targets for batteries, PV, and electrolyzers.
关键词： Techno-economic analysis,Technology roadmap,Off-grid production,Proton-exchange membrane electrolyzer
更新于2025-09-23 15:23:52
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Improvement of the ON/OFF Switching Performance of a pH-Activatable Porphyrin Derivative by the Introduction of Phosphorus(V)
摘要： An activatable photosensitizer for singlet oxygen is of significance due to its potential applications for high tumor-specific photodynamic therapy and diagnosis. In this study, a pH-activatable system that enables the specific photosensitization of singlet oxygen at a low pH was developed based on the complexation of a porphyrin–aniline conjugate with phosphorus(V). As a result of complexation with phosphorus, the water solubility of the porphyrin–aniline conjugate was improved by 100 times. Furthermore, this complexation strongly suppressed the singlet-oxygen-generating activity of the porphyrin photosensitizer under basic conditions, and the quantum yield of the singlet oxygen photosensitization markedly increased under acidic conditions. Based on these improvements, an extremely high ON/OFF switching ratio of the quantum yield was obtained (>400 times).
关键词： pH activatable photosensitizer,ON/OFF switching,singlet oxygen,aniline,phosphorous porphyrin,protonation,fluorescence,acid
更新于2025-09-23 15:23:52
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Design and optimization of grid-tied and off-grid solar PV systems for super-efficient electrical appliances
摘要： Modeling, simulation, and optimization methods are used in the present study to design grid-tied and off-grid solar PV systems for super-efficient electrical appliances for residential buildings. The principal objective of this study is to design a renewable energy system to serve the electric load of super-efficient appliances with high penetration of renewable resources and low greenhouse gas emissions and cost of energy. Hourly calculations using optimization method are used to study the daily and yearly performance and the cost of the renewable energy systems. A comparison between the performance of the grid-tied and off-grid solar PV systems using conventional and super-efficient appliances in Dubai is presented. The comparison includes the total power production from the solar PV system, the power purchased from the grid, the extra power sold to the utility grid, the power used to meet the electrical load of the appliances, the excess power, the renewable fraction, the greenhouse gas emissions, and the levelized cost of energy. The results of the simulation show that the integration of super-efficient appliances powered with the grid-tied solar power system is a good option to control the energy consumption of the residential buildings and to reduce the cost of electricity and greenhouse gas emissions: low building energy consumption (reduction by half of the electrical power consumption: from 62.91 to 30.78 kWh/day using super-efficient appliances); all the electrical power demand for the building is met without shortage; the power systems produce low excess power (0.29–1.82%) compared to the off-grid power system; all the extra power from the solar PV is sold back to the grid to reduce the cost of energy, high renewable fraction (68% of the total energy served to the load is produced from solar PV), low-cost of electricity (12% reduction of the cost of energy compared to the utility grid), and low greenhouse gas emissions (45–51% reductions of the CO2, NOX, and SO2 emissions compared to the conventional electrical appliances).
关键词： Grid-tied solar PV,Off-grid solar PV,Super-efficient appliances,Energy efficiency,Renewable energy
更新于2025-09-23 15:23:52