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[Display omitted] • Portable HSI technology reliably assessed the maturity of Camellia oleifera fruits in-field. • Ten quality indexes were measured for three maturity stages of Camellia oleifera. • The comprehensive maturity index (CMI) was obtained through factor analysis. • The CMI prediction models for Camellia oleifera fruits were built based on DL and ML. • Develop the discrimination model of Camellia oleifera fruits maturity stages. To efficiently detect the maturity stages of Camellia oleifera fruits, this study proposed a non-invasive method based on hyperspectral imaging technology. First, a portable hyperspectral imager was used for the in-field image acquisition of Camellia oleifera fruits at three maturity stages, and ten quality indexes were measured as reference standards. Then, factor analysis was performed to obtain the comprehensive maturity index (CMI) by analyzing the change trends and correlations of different indexes. To reduce the high dimensionality of spectral data, the successive projection algorithm (SPA) was employed to select effective feature wavelengths. The prediction models for CMI, including partial least squares regression (PLSR), support vector regression (SVR), extreme learning machine (ELM), and convolutional neural network regression (CNNR), were constructed based on full spectra and feature wavelengths; for CNNR, only the raw spectra were used as input. The SPA-CNNR model exhibited more promising performance (R P = 0.839, RMSEP = 0.261, and RPD = 1.849). Furthermore, PLS-DA models for maturity discrimination of Camellia oleifera fruits were developed using full wavelength, characteristic wavelengths and their fusion CMI, respectively. The PLS-DA model using the fused dataset achieved the highest maturity classification accuracy, with the best simplified model achieving 88.6 % accuracy in prediction set. This study indicated that a portable hyperspectral imager can be used for in-field determination of the internal quality and maturity stages of Camellia oleifera fruits. It provides strong support for non-destructive quality inspection and timely harvesting of Camellia oleifera fruits in the field. [ABSTRACT FROM AUTHOR]

A novel multifunctional probe, L , based on triphenylamine o -hydroxyl Schiff base was constructed for the sequential detection of Zn 2+ /P 2 O 7 4− . Interestingly, probe L also showed two-photon fluorescent “off-on” response to Zn 2+ along with a large effective two-photon absorption cross-section value of 240 GM at 720 nm, a low cytotoxic and a moderate photostability, which made L a good candidate for two-photon fluorescence microscopy imaging and monitoring the fluctuation of exogenous Zn 2+ . [ABSTRACT FROM AUTHOR]

A newly designed fluorescence dye L based on di-2-picolyamine (DPA) moiety as a chelator was obtained under the protection of N 2 at 120 °C, and KI as catalyst with relatively better yield. More interestingly, L not only could selectively and sensitively detect Cu 2+ ions in aqueous medium but also examine the Cu 2+ ions of the actual water samples. Nevertheless, L could be visual in Hela cells with excellent cell permeability, viz , monitoring exogenous Cu 2+ ions as well as realizing an “on–off–on” process. [ABSTRACT FROM AUTHOR]

A series of water-soluble stilbazolium salts with A-π-A (A: Acceptor) model have been synthesized and fully characterized. The results obtained from absorption spectra and TD-DFT computational studies show that there is a relative strong intramolecular charge transfer (ICT) transition from pyridine unit to pyridine cation of the stilbazolium salts. Furthermore, it is found that the three stilbazolium salts ( T1 , T2 , T3 ) show the strong two-photon absorption (2PA) response in the near-infrared (IR) region by Z -scan technique using femtosecond laser. And the stilbazolium salt T3 shows the largest two-photon absorption cross-section and third-order nonlinear optical (NLO) coefficient χ (3) at 730 nm, indicating the different terminal substituent group of the pyridinium plays a vital role in third-order NLO behavior. [ABSTRACT FROM AUTHOR]

[Display omitted] • The validity for HSI system in identifying authenticity of mutton kebabs was proved. • Both the fresh and cooked states of mutton kebabs were investigated. • PLS-DA, KNN, and SVM were individually used to develop discriminant models. • Compared to IVSO, RF and SPA, PC loadings selected variables were the optimal. • Pixel-wise distribution maps were built to visualize the identification. Mutton kebab is an attractive type of meat product with high nutritional value, and is favored by consumers worldwide. However, mutton kebab is often subjected to adulteration due to its high price. Chicken, duck, and pork are frequently used as adulterated substitutes. The purpose of current study aims at developing a methodology based on hyperspectral imaging (HSI, 400–1000 nm) for identifying the authenticity of fresh and cooked mutton kebabs. Kebab samples were individually scanned using HSI system in their fresh and cooked states. Spectra of chicken, duck, pork, and mutton kebabs were first extracted from representative regions of interest (ROIs) identified in their calibrated hyperspectral images. After that, principal component analysis (PCA) was carried out, and results showed that the first three or two PCs were effective for identifying fresh or cooked samples of different meat species. Different effective modeling algorithms including k -nearest neighbor (KNN), partial least squares discriminant analysis (PLS-DA), and support vector machine (SVM) algorithms combined with different preprocessing methods were employed to develop classification models. Performances exhibited that PLS-DA models using raw spectra outperformed the KNN and SVM models, and the accuracies reached both 100 % in prediction sets for fresh and cooked meat kebabs, respectively. Moreover, compared to iteratively variable subset optimization (IVSO), random frog (RF), and successive projections algorithm (SPA) algorithms, the PC loadings successfully screened 14 and 8 effective wavelengths for fresh and cooked meat kebabs, respectively, from the complex original full-band wavelengths. The PC-PLS-DA models showed the optimal predicted performances with overall classification accuracies of 97.5 % and 100 %, sensitivity values of 1.00 and 1.00, specificity values of 0.97 and 1.00, precisions of 0.91 and 1.00, for fresh and cooked mutton kebabs, respectively. Furthermore, the visualization of classification maps confirmed the experimental results intuitively. Overall, it was evident that HSI showed immense potential to identify the authenticity of fresh and cooked mutton kebabs when substituted by different meats including chicken, duck, and pork. [ABSTRACT FROM AUTHOR]

Two new triphenylamine-cored probes ( L1 , L2 ) with different receptor units have been synthesized and fully characterized by IR, NMR and MS spectra. Their photophysical properties have been investigated in detail. The recognition abilities of two probes were evaluated by a series of metal ions, which showed that L1 could recognize Cu 2+ over other metal ions. L2 could respond to Cu 2+ , Hg 2+ in a short time, which interferes with a little each other. The Job’s plot and 1 H NMR titration of L1 with Cu 2+ and L2 with Cu 2+ (Hg 2+ ) in CD 3 CN verified the coordination mode of complexes L1 -Cu 2+ , L2 -Cu 2+ and L2 -Hg 2+ , respectively. The limit of detection of L2 for Cu 2+ was lower than that of L1 towards Cu 2+ . The results demonstrated that the receptor units in the probes had remarkable effect on recognizing metal ions. Meanwhile, L1 and L2 showed potential application in bio-imaging after mixing with Cu 2+ . [ABSTRACT FROM AUTHOR]

A specific series of chromophores ( CN1 , CN2 , CN3 , and CN4 ) have been synthesized, in which contained a triphenylamine moiety as the electron donor (D), a cyanoacetic acid moiety as the electron acceptor (A), vinylene or phenylethyne as the π -bridge, and ethyoxyl groups as auxiliary electron donor (D′) to construct the D- π -A or D′–D- π -A molecular configuration. Photophysical properties of them were systematically investigated. These results show that the chromophores display a solvatochromism (blue shift) and large Stokes shifts for their absorption bands with increasing polarity of the solvent. Furthermore, the chromophore CN4 shows the strongest intensity of two-photon excited fluorescence and largest two-photon absorption cross section (2783 GM) in the near infrared region. Finally, the connections between the structures and properties are systematically investigated relying on the information from linear and nonlinear optical properties, crytsal structures and quantum chemical calculation. [ABSTRACT FROM AUTHOR]

Two isomorphic theranostic agents, named 6-TDE and 7-TDE, were designed and prepared by substituent position modification, exhibiting the grid-like and wave-like structure. Specially, 7-TDE possessed favorable ROS (Type I and Type II) as well as self-monitoring mitochondrial autophagy and multimodal imaging. [Display omitted] • Two interesting packing modes, the grid-like and wave-like structure through substituent position modification on packing mode. This study provides the new insight into the "Formula-Aggergete-Property" relationship of chemical structure. • A photosensitizer capable of photodynamic therapy (Type I and Type II) and self-monitoring mitochondrial autophagy. • The photosensitizer presented outstanding performance in multimodal imaging, including fluorescence imaging (FLI), photoacoustic imaging (PAI) and photothermal imaging (PTI). Precise design of organic photosensitizers (PSs) promoted the technological innovation for multimodal imaging-guided synergistic therapy. Nonetheless, various group substitution could not only optimize the basic photophysical behavior, but possibly change the aggregate, which handicaps the deep understanding of the "Formula-Aggergete-Property" relationship. Bearing this in mind, herein two isomers, named 6-TDE and 7-TDE , were prepared via substituting position modification. Among them, 6-TDE exhibited the grid-like structure, while 7-TDE presented wavy-like structure. Despite the aggregates were different, 6-TDE and 7-TDE shared common features including partly twisted backbone and non-overlapped-orbit, hence resulting in similar optical physical behavior such as decent extinction coefficient, near-IR emission, large stockes shifts, etc. Meanwhile, though two PSs could both generated Type-I and Type-II ROS, 7-TDE possessed smaller singlet–triplet splitting (ΔE ST), which exhibited favorable ROS as well as outstanding mitochondrial targeting, achieving efficient photodynamic therapy (PDT) effect. During this process, mitochondrial autophagy could be tracked and observed effectively and in real-time. Moreover, 7-TDE presented outstanding performance in multimodal imaging, including fluorescence imaging (FLI), photoacoustic imaging (PAI) and photothermal imaging (PTI). This study enriches the strategy of precise molecular engineering to optimize theranostic agents. [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis and characterization of two novel 6′-phenyl-2,2′-bipyridine ligands (L1, L2) and their CdL1,2 I2 complexes are presented. [•] Single crystal study indicated that Cd(II) ion is in a distorted tetrahedral structure. [•] Linear absorption and single-photon exited fluorescence properties have been investigated. [•] The results showed that the complex 2 has the longest fluorescence lifetime. [•] Linear absorption spectral features are studied by TD-DFT methods. [Copyright &y& Elsevier]

Highlights: [•] We have synthesized four D–π–D dyes with two-photon absorption. [•] Four dyes contain phenothiazines/carbazoles with styrene/biphenylethyne as bridge. [•] Photophysical properties of four dyes were investigated. [•] Donors have larger contribution to σ value than that of conjugated bridge. [•] Four dyes can be used as organic two-photon photopolymerization initiators. [Copyright &y& Elsevier]

Lipid droplets (LDs) are organelles featuring in intracellular storage of neutral lipids, which are involved with many biological processes. Monitoring the dynamical cyclic behaviors of cellular LDs poses great importance for early disease diagnosis. Herein, two coumarin-based LDs-specific fluorescence probes exhibited "turn-on" and two-photon fluorescence triggered by breaking their aggregation states. By virtue of establishing oil/water emulsions model to simulate LDs, the behaviors of "turn-on" fluorescence were elucidated, which benefited for the enhancement of selectivity of the probes to LDs. Then, we highlight a LDs-specific coumarin-based two-photon probe (L1) with high photo-stability to monitor the dynamic cyclic behaviors of LDs in cells, unraveling the changes of LDs quantity during lipophagy and the reproduction of LDs to prevent lipotoxicity. We believe the probe offers a convenient way to investigate the biology of LDs. Probe L1 was used to document the changes of the LDs quantity during lipophagy and the reproduction of LDs to prevent lipotoxicity. Unlabelled Image • Two novel coumarin-based "turn-on" lipid droplets-specific two-photon bioprobes, L1 and L2 , were reported. • Oil/water emulsions successfully explained fluorescence "turn-on" behavior of two probes. • The two-photon probe (L1) with high specificity towards LDs to monitor the dynamic cyclic behaviors of LDs in cells • The probe L1 could be used to wonderfully monitor the lipid droplets accumulation associated with obesity. [ABSTRACT FROM AUTHOR]