- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - 3DMAX-Net: A Multi-Scale Spatial Contextual Network for 3D Point Cloud Semantic Segmentation
摘要： Semantic segmentation of 3D scenes is a fundamental problem in 3D computer vision. In this paper, we propose a deep neural network for 3D semantic segmentation of raw point clouds. A multi-scale feature learning block is first introduced to obtain informative contextual features in 3D point clouds. A global and local feature aggregation block is then extended to improve the feature learning ability of the network. Based on these strategies, a powerful architecture named 3DMAX-Net is finally provided for semantic segmentation in raw 3D point clouds. Experiments have been conducted on the Stanford large-scale 3D Indoor Spaces Dataset using only geometry information. Experimental results have clearly shown the superiority of the proposed network.
关键词： 3D semantic segmentation,point clouds,multi-scale feature learning,feature aggregation,deep learning
更新于2025-09-09 09:28:46
-
Fractal simulation of thin film nucleation growth process using a diffusion-limited aggregation model
摘要： In order to study the initial nucleation and growth process of the films, a two-dimensional (2D) DLA model was established, and fractal dimension was calculated by sandbox method. Compared with the experimental results, the model can well characterize the morphology of nucleation and growth in the initial stage of film growth. In addition to the number of particles and deposition probability involved in other studies, the size of substrate and the location of central particles are also considered in this work. The growth morphology, fractal dimension and the number of simulated steps are presented in this paper.
关键词： thin film,Diffusion-limited aggregation,2D DLA,nucleation growth,fractal dimension
更新于2025-09-09 09:28:46
-
Triphenylethylene- and Tetraphenylethylene-Functionalized 1,3-Bis(pyrrol-2-yl)squaraine Dyes: Synthesis, Aggregation-Caused Quenching to Aggregation-Induced Emission, and Thiol Detection
摘要： Three novel pairs of 1,3-bis(pyrrol-2-yl)squaraine dyes, N-alkylated SQ1a?1b, and N-phenylated SQ2a?2b in which triphenylethylene moieties functionalized at 5-position of pyrrole, as well as SQ3a?3b with tetraphenylethylene (TPE) moieties attached at N-position of pyrrole, were synthesized. All six dyes were found not to exhibit aggregation-induced emission (AIE) properties. Spectrophotometric studies showed that N-TPE-functionalized SQ3a?3b exhibited much larger molar extinction coefficients (ε: 1.36?2.14 × 105 M?1 cm?1) than 5,5′-triphenylethylene-functionalized SQ1a?2b (ε: 2.17?8.22 × 104 M?1 cm?1). Surprisingly, SQ2b showed a remarkable red-shifted maximum absorption (λmax: 723 vs 631?652 nm) compared to that of other squaraine dyes. All six squaraine dyes selectively responded to the addition of thiol-containing biomolecules, such as cysteine and gluthatione, with the disappearance of λmax in the near-infrared region in their respective absorption spectra. Interestingly, the thiolated species of SQ3a?3b were AIE active, with the characteristic AIE emission of TPE at λmax = 484?490 nm upon addition of water. Further thiol sensing on solid supports was examined, indicating the potential applications of TPE-functionalized squaraine dyes as bioprobes for the detection of important thiol-containing biomolecules, with a clear change from aggregation-caused quenching to AIE.
关键词： bioprobes,aggregation-induced emission,near-infrared,thiol detection,squaraine dyes
更新于2025-09-09 09:28:46
-
Mechanical Insights into Aggregation-Induced Delayed Fluorescence Materials with Anti-Kasha Behavior
摘要： Organic materials with aggregation-induced delayed fluorescence (AIDF) have exhibited impressive merits for improving electroluminescence efficiency and decreasing efficiency roll-off of nondoped organic light-emitting diodes (OLEDs). However, the lack of comprehensive insights into the underlying mechanism may impede further development and application of AIDF materials. Herein, AIDF materials consisting of benzoyl serving as an electron acceptor, and phenoxazine and fluorene derivatives as electron donors are reported. They display greatly enhanced fluorescence with increased delayed component upon aggregate formation. Experimental and theoretical investigations reveal that this AIDF phenomenon can be rationally ascribed to the suppression of internal conversion and the promotion of intersystem crossing in solid. Moreover, the theoretical calculations disclose that the efficient solid-state delayed fluorescence originates from the higher energy electronic excited state (e.g., S2) rather than the lowest energy-excited state (S1), demonstrating an anti-Kasha behavior. The excellent AIDF property allows high exciton utilization and thus superb performance of OLEDs using these new materials as light-emitting layers.
关键词： aggregation-induced delayed fluorescence,anti-Kasha emission,intersystem crossing,internal conversion,organic light-emitting diodes
更新于2025-09-09 09:28:46
-
Segmental <sup>13</sup> C-Labeling and Raman Microspectroscopy of α-Synuclein Amyloid Formation
摘要： Mapping conformational changes of a-synuclein (a-syn) from soluble, unstructured monomers to b-sheet-rich aggregates is crucial towards understanding amyloid formation. Raman microspectroscopy is now used to spatially resolve conformational heterogeneity of amyloid aggregates and monitor amyloid formation of segmentally 13C-labeled a-syn in real-time. As the 13C-isotope shifts the amide-I stretching frequency to lower energy, the ligated construct, 12CS87C–140-a-syn, exhibits two distinct bands allowing for simultaneous detection of secondary structural changes in N-terminal 1–86 and C-terminal 87–140 residues. The disordered-to-b-sheet conformational change is first observed for the N-terminal followed by the C-terminal region. Finally, Raman spectroscopic changes occurred prior to Thioflavin T fluorescence enhancement, indicating that the amide-I band is a superior probe of amyloid formation.
关键词： chemical ligation,aggregation,b-sheets,transmission electron microscopy,kinetic intermediates
更新于2025-09-09 09:28:46
-
Rapid Detection of Aromatic Pollutants in Water Using Swellable Micelles of Fluorescent Polymers
摘要： We constructed a kind of novel swellable fluorescent micelles for rapid and sensitive detection of toxic aromatic pollutants (APs) in water based on capture-report strategy. An amphiphilic triblock copolymer capped with an aggregation induced emission (AIE) chromophore self assembled into micelles with core-shell structures in aqueous solution. Hydrophobic segments of block polymers organized into cores with the AIE chromophore near the core/shell interface, which were stabilized by a corona of water-soluble polymer segments. Water-soluble polymer segments captured APs in water. The captured pollutants were subsequently transported to hydrophobic cores of micelles. The cores swelled after absorbing APs, leading to fluorescence quenching of the AIE chromophores. The fluorescent micelles allowed rapid detection of APs in the order of seconds at a concentration of 1 ug/L. Compared with commercial GC-MS, the fluorescent micelles require a much smaller amount sample and are much quicker with comparable sensitivity. With the merits of high sensitivity, rapid response, simple operation procedures, and low cost, the fluorescent micelles provide an ideal candidate for the facile detection of toxic aromatic pollutants in water.
关键词： Polymer,Fluorescence,Micelle,Aromatic pollutant,Aggregation-induced emission
更新于2025-09-09 09:28:46
-
Determination of the activity of alkaline phosphatase based on?aggregation-induced quenching of the fluorescence of?copper nanoclusters
摘要： A rapid method is described for synthesis of copper nanoclusters (CuNCs) by utilizing L-histidine as the stabilizer and ascorbic acid (AA) as the reductant. The CuNCs display blue-green fluorescence with excitation/emission peaks at 390/485 nm. A sensitive fluorometric assay was worked out for determination of alkaline phosphatase (ALP) activity. If the ALP substrate p-nitrophenylphosphate (PNPP) is enzymatically hydrolyzed, it forms p-nitrophenol (PNP) which reduces the fluorescence of CuNCs because its absorption band at 410 nm overlaps the excitation peak of CuNCs at 390 nm. In addition, the amino groups and imidazole groups on the surface of CuNCs possibly form a complex with the phenol groups of PNP. This induces aggregation-induced quenching of the fluorescence of CuNCs. The fluorescent probe has a linear analytical range that extends from 0.5 mU·mL?1 to 40 mU·mL?1 and a detection limit of 45 μU·mL?1.
关键词： Alkaline phosphatase,Aggregation-induced quenching,Fluorometry,Inner filter effect,L-Histidine,Copper nanoclusters
更新于2025-09-04 15:30:14
-
Fluorescent biosensor for detection of the R248Q aggregation‐prone mutant of p53
摘要： The p53 tumour suppressor and guardian of the genome undergoes missense mutations which lead to functional inactivation in 50% human cancers. These mutations occur mostly in the DNA-binding domain of the protein and several of these result in conformational changes which lead to amyloid-like protein aggregation. Here we describe a fluorescent biosensor that reports on the R248Q mutant of p53 in vitro and in living cells, engineered through conjugation of an environmentally-sensitive probe onto a peptide derived from the primary aggregation segment of p53.This biosensor was characterized both in vitro and by fluorescence microscopy following facilitated delivery into cultured cells. We show that this biosensor preferentially reports on the p53 R248Q mutant in PC9 lung cancer cell line compared to other lung cancer cell lines harbouring either wildtype or no p53.
关键词： p53,lung cancer,fluorescent biosensor,peptide,aggregation
更新于2025-09-04 15:30:14
-
Bis[1]benzothieno[1,4]thiazines - Planarity, Enhanced Redox Activity and Luminescence by Thieno-Expansion of Phenothiazine
摘要： Twofold Buchwald-Hartwig aminations selectively furnish all three regioisomers of bis[1]benzothieno[1,4]thiazines and X-ray structure analyses and DFT calculations were corroborated for correlation of their electronic properties. All regioisomers outscore the parent compound phenothiazine with respect to a low lying oxidation potential and reversible redox activity. The anti-anti bis[1]benzothieno[3,2-b:2',3'-e][1,4]thiazines possess lowest oxidation potentials in this series and display pronounced green luminescence in solution (?F ≈ 20%) and in the solid state. Syn-anti regioisomers are only weakly luminescent in solution, but show aggregation induced emission enhancement and solid state luminescence. Most interestingly, found by X-ray structure analyses anti-anti derivatives reveal an amazingly coplanar structure of the pentacyclic anellated 1,4-thiazine system, emphasizing a structural similarity to heteroacenes. The calculated theoretical nucleus-independent chemical shifts additionally suggest that the 8?-electron core systems can be considered as first electronically unbiased anellated 1,4-thiazines with antiaromatic character.
关键词： Heterocycles,1,4-Thiazines,Fluorescence,Buchwald-Hartwig coupling,Cyclic voltammetry,Absorption,Antiaromaticity,Aggregation induced emission enhancement,Polymorphism,DFT calculations
更新于2025-09-04 15:30:14
-
AIEgen Nanoparticles of Arylamino Fumaronitrile Derivative with High Near-infrared emission for Two-photon Imaging and in vivo Cell Tracking
摘要： Developing of two-photon materials for live-cell imaging and in vivo analysis in-deep have been received great attention, and it is still urgent so that such microscopy technique could be promoted and advanced into new progress using the powerful probs. Herein, a new arylamino fumaronitrile derivative NPAPF was synthesized and transferred as aggregation-induced emission luminogen (AIEgen) fluorescent nanoparticles (AF-NPs) via assembly technique. This AF-NPs exhibited two-photon absorption cross-section at 2.6×106 GM with 19.5% of fluorescence quantum yield. Moreover, utilizing the great potential of AF-NPs, two-photon imaging of live cells with good cytocompatibility is realized upon two-photon microscopy. By in vivo long-term tracing studies of mesenchymal stem cells, we demonstrated the tremendous advantage of AF-NPs tracer in monitoring the stem cells transplant. Therefore, our unique AF-NPs provided an efficient two-photon-absorbing probe for investigating biological mechanism and behavior, and also opened a new avenue for spatiotemporal visualization of transplanted stem cells.
关键词： organic nanoparticles,aggregation-induced emission,two-photon,in vivo imaging,mesenchymal stem cell
更新于2025-09-04 15:30:14