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A new strategy for utilizing activated CH-group to construct a FRET platform for ratiometric sensing of cyanides
摘要： A fluorescent and colorimetric cyanide sensor (4-Br) based on the activated C-H group to construct a FRET platform has been described for the first time, along with demonstration of selective and reversible detection of cyanides through it. The sensing mechanism of 4-Br is an integration of ICT and FRET mechanisms, based on the deprotonation of the activated C-H group. Importantly, it is suitable for fluoresence imaging of cyanides in living cell.
关键词： Fluorescent probe,Colorimetric,FRET,ratiometric,Cyanide
更新于2025-09-10 09:29:36
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Time-Resolved Structured Illumination Microscopy for Phase Separation Dynamics of Water and 2-Butoxyethanol Mixtures: Interpretation of “Early Stage” Involving Micelle-Like Structures
摘要： Phase separation dynamics of a water/2-butoxyethanol (2BE) mixture was studied with newly developed time-resolved structured illumination microscopy (SIM). Interestingly, an employed hydrophobic fluorescent probe for SIM showed spectral shifts up to 500 ns after a laser-induced temperature jump, which suggests 2BE micellar-like aggregates become more hydrophobic at the initial stage of phase separation. This hydrophobic environment in 2BE aggregates, probably due to the ejection of water molecules, continued up to at least 10 μs. Time-resolved SIM and previously-reported light scattering data clearly showed that the size of a periodic structure remained constant (ca. 300 nm) from 3 to 10 μs, and then the growth of periodic structures having the self-similarity started. We think that the former and the latter processes correspond to “early stage” (concentration growth) and “late stage” (size growth), respectively, in phase separation dynamics. Here we suggest that, in the early stage, the entity to bear 2BE phase be water-poor 2BE aggregates, and the number density of these aggregates would simply increase in time.
关键词： phase separation dynamics,hydrophobic fluorescent probe,2-butoxyethanol,structured illumination microscopy,micellar-like aggregates
更新于2025-09-10 09:29:36
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Sub-20 fs All-Optical Switching in a Single Au-Clad Si Nanodisk
摘要： Dielectric nanoantennas have recently emerged as promising elements for nonlinear and ultrafast nanophotonics due to their ability to concentrate light on the nanometer scale with low losses, while exhibiting large nonlinear susceptibilities. In this work, we demonstrate that single Si nanodisks covered with a thin 30-nm thick layer of Au can generate positive and negative sub-20 fs reflectivity modulations of ?0.3% in the vicinity of the first-order anapole mode, when excited around the second-order anapole mode. The experimental results, characterized in the visible to near infrared spectral range, suggest that the nonlinear optical Kerr effect is the responsible mechanism for the observed all-optical switching phenomena. These findings represent an important step toward nanoscale ultrafast all-optical signal processing.
关键词： anapole modes,optical Kerr effect,ultrafast all-optical switching,pump-probe spectroscopy,Dielectric nanoantennas
更新于2025-09-10 09:29:36
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Intraoperative Probe-Based Confocal Endomicroscopy to Histologically Differentiate Thyroid From Parathyroid Tissue Before Resection
摘要： Background. Frozen section is the standard method to histologically distinguish parathyroid tissue from thyroid tissue during endocrine neck surgery. Frozen section can be time-consuming and costly. Its drawback is that it is to be performed only after the removal of a suspected pathological tissue. This study demonstrates the use of probe-based confocal laser endomicroscopy (pCLE) to confirm histology prior to tissue resection. Design. A prospective, single-institution, nonrandomized study was conducted. No sample size calculation was performed for this observational trial. The primary objective was the description of histological rendering of normal and pathological tissues through pCLE. Real-time in vivo fluorescence microscopy imaging was performed with the CystoFlex UHD probe after intravenous injection of 2.5 mL of 10% fluorescein sodium. Results. Eleven patients with hyperparathyroidism and thyroid conditions were included. A total of 104 videos showing thyroid, parathyroid, adipose tissue, muscle, laryngeal nerve, and lymph nodes were recorded. Videos were compared with visual information and pathological samples (when sampling was indicated). Thyroid tissue could be identified based on the presence of colloid follicles (intensely fluorescent area surrounded by a small ridge of low-fluorescence epithelial cells) including the pathognomonic aspect of resorption vacuole. Parathyroid tissue could be identified based on a regular, “diamond-shaped” capillary network encompassing parathyroid chief cells. Blinded reinterpretation of pCLE videos demonstrated an 89.3% sensitivity and a 90% specificity as compared with histology in tissue recognition. Conclusion. This pilot study describes representative renderings of intraoperative pCLE to nontraumatically differentiate thyroid, parathyroid, and lymph nodes before surgical removal.
关键词： parathyroidectomy,thyroid surgery,pCLE,in vivo fluorescence microscopy,probe-based confocal laser endomicroscopy
更新于2025-09-10 09:29:36
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Correlated Materials Characterization via Multimodal Chemical and Functional Imaging
摘要： Multimodal chemical imaging simultaneously offers high resolution chemical and physical information with nanoscale, and in select cases atomic resolution. By coupling modalities that collect physical and chemical information, we can address scientific problems in biological systems, battery and fuel cell research, catalysis, pharmaceuticals, photovoltaics, medicine and many others. The combined systems enable local correlation of material properties with chemical makeup, making fundamental questions in how chemistry and structure drive functionality approachable. In this review we present recent progress and offer a perspective for chemical imaging used to characterize a variety of samples by a number of platforms. Specifically, we present cases in infrared and Raman spectroscopies combined with scanning probe microscopy; optical microscopy and mass spectrometry; nonlinear optical microscopy; and finally, ion, electron and probe microscopies with mass spectrometry. We also discuss the challenges associated with the use of data originated by the combinatorial hardware, analysis, and machine learning as well as processing tools necessary for interpretation of multidimensional data acquired from multimodal studies.
关键词： raman spectroscopy,ion microscopy,nonlinear optical microscopy,mass spectrometry,electron microscopy,infrared spectroscopy,chemical imaging,scanning probe microscopy,data analytics,optical microscopy
更新于2025-09-10 09:29:36
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Scanning probe microscopy and potentiometry using a junction field effect transistor based sensor
摘要： Scanning tunneling microscopy in its conventional form relies on a steady state tunneling current of 10?12–10?6 A. However, for various applications, it is desirable to reduce the current load to a minimum. Here, we present first experiments using a cooled junction field effect transistor in open gate operation, thereby reducing the DC-current to less than 10?19 A. This enables almost ideal measurements of the local electrochemical potential on a surface. Various methods applying dynamic modes can be used to maintain a constant distance between the scanning probe and the sample surface. Here, we use an AC-bias applied to the sample and a lock-in amplifier connected to the preamplifier to evaluate the conductance of the tunneling gap.
关键词： potentiometry,scanning probe microscopy,junction field effect transistor,sensor
更新于2025-09-09 09:28:46
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Surface potential of meso-dimensional ZnS:Mn particles obtained using SHS method
摘要： The dependence of surface potential value on the particle size of micro- and meso-fractions for powdered ZnS:Mn obtained using self-propagating high-temperature synthesis has been investigated. Rather good agreement of model representations for the change in the value of surface potential for the particle with its size changed due to overlapping the space charge regions from opposite surfaces within the range ~ 1 ≤ R/Leff ≤ ~ 2.2 (R, particle radius; Leff, screening length) with experimental data obtained using the method of Kelvin probe microscopy has been shown. The value of Leff for ZnS:Mn particles is estimated as approximately 30 nm.
关键词： Surface potential,Nanoscale effects,ZnS:Mn,Particle size,Effective screening length,Kelvin probe force microscopy
更新于2025-09-09 09:28:46
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[IEEE 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Xuzhou, China (2018.7.21-2018.7.24)] 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - A Transition Beween Single-Layer Substrate Integrated Image Guide and Coaxial Probe
摘要： The substrate integrated image guide (SIIG) is a planar transmission line with low-loss and high-Q properties. To reduce the fabrication complexity, the SIIG realized by the single-layer PCB technology is introduced. The differences between this type of SIIG and the conventional one are analyzed. A feasible method is proposed to minimize the additional leakage loss caused by the single-layer PCB process and achieve the similar performance compared with the conventional SIIG. A SIIG line working from 13.2GHz to 14.8GHz is designed utilizing this method. Then, a single-layer transition from a coaxial probe to the SIIG is presented. A 132.2 mm long single-layer PCB-based SIIG with such a transition is designed and fabricated. The measured results show that insertion loss is better than 4.25dB while the return loss is under –10dB from 13.2 GHz to 14.8 GHz.
关键词： PCB techonology,substrate integrated image line (SIIG),co-axial probe feeding,single-layer transition
更新于2025-09-09 09:28:46
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How pump–probe differential reflectivity at negative delay yields the perturbed-free-induction-decay: theory of the experiment and its verification
摘要： We present a simple but mathematically complete first-principles theory for the pump–probe differential reflectivity experiment at negative delay (probe preceding the pump) to show how it gives information about the perturbed-free-induction-decay of coherent polarization. The calculation, involving the optical Bloch equations to describe the induced polarization and the Ewald–Oseen idea to calculate the reflected signal as a consequence of the free oscillations of perturbed dipoles, also explicitly includes the process of lock-in detection of a double-chopped signal after it has passed through a monochromator. The theory giving a closed form expression for the measured signal in both time and spectal domains is compared with experiments on high quality GaAs quantum well sample. The dephasing time inferred experimentally at 4 K compares remarkably well with the inverse of the absorption linewidth of the continuous-wave photoluminescence excitation spectrum. Spectrally-resolved signal at negative delay calculated from our theoretical expression nicely reproduces the coherent spectral oscillations observed in our experiments, although exact fitting of the experimental spectra with the theoretical expression is difficult on account of multiple resonances.
关键词： pump–probe theory and experiment,perturbed-free-induction-decay,optical Bloch equations,Ewald–Oseen extinction theorem,excitonic polarization dephasing
更新于2025-09-09 09:28:46
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Visualizing Endogenous Sulfur Dioxide Derivatives in Febrile Seizure-Induced Hippocampal Damage by a Two-Photon Energy Transfer Cassette
摘要： Febrile seizure (FS), a frequently encountered seizure disorder in pediatric populations, can cause hippocampus damage. It has been elucidated that sulfur dioxide (SO2) content is overproduced during the development of FS and related brain injury. Thus, in situ monitoring the level of endogenous SO2 in FS-related models is helpful to estimate the pathogenesis of FS-induced brain injury, but effect detection method remains to be explored. Herein, we developed a two-photon energy transfer cassette based on acedan-anthocyanidin scaffold, TP-Ratio-SO2, enabling to achieve this purpose. TP-Ratio-SO2 specifically responds to SO2 derivatives (HSO3-/SO32-) in ultrafast fashion (less than 3s), and HSO3-/SO32- can be sensitively determined with a detection limit of 26 nM. Moreover, it exhibits significant changes in two well-resolved ?uorescence emission (?λ = 140 nm) by reacting with HSO3-/SO32-, behaving as a ratiometric fluorescent sensor. Importantly, ratiometric imaging of endogenous SO2 derivatives generation in hyperpyretic U251 cells and as well as in rat model of FS-treated hippocampus damage were successfully carried out by TP-Ratio-SO2, demonstrating that it may be a promising tool for studying the role of SO2 in FS-associated neurological diseases.
关键词： Two-photon fluorescence probe,Febrile seizure,Sulfur dioxide,Ratiometric imaging,Hippocampus damage
更新于2025-09-09 09:28:46