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Remote sensing bio-control damage on aquatic invasive alien plant species
摘要： Aquatic Invasive Alien Plant (AIAP) species are a major threat to freshwater ecosystems, placing great strain on South Africa’s limited water resources. Bio-control programmes have been initiated in an effort to mitigate the negative environmental impacts associated with their presence in non-native areas. Remote sensing can be used as an effective tool to detect, map and monitor bio-control damage on AIAP species. This paper reconciles previous and current research concerning the application of remote sensing to detect and map bio-control damage on AIAP species. Initially, the spectral characteristics of bio-control damage are described. Thereafter, the potential of remote sensing chlorophyll content and chlorophyll fluorescence as pre-visual indicators of bio-control damage are reviewed and synthesised. The utility of multispectral and hyperspectral sensors for mapping different severities of bio-control damage are also discussed. Popular machine learning algorithms that offer operational potential to classify bio-control damage are proposed. This paper concludes with the challenges of remote sensing bio-control damage as well as proposes recommendations to guide future research to successfully detect and map bio-control damage on AIAP species.
关键词： machine learning algorithms,multispectral sensors,chlorophyll content,Aquatic Invasive Alien Plant (AIAP) species,chlorophyll fluorescence,hyperspectral sensors,Remote sensing,bio-control damage
更新于2025-09-23 15:19:57
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A phenylboronate-based SERS nanoprobe for detection and imaging of intracellular peroxynitrite
摘要： A surface-enhanced Raman scattering (SERS) based nanoprobe was developed for detection and imaging of endogenous peroxynitrite in living cells. The probe was fabricated by assembling 3-mercaptophenylboronic acid pinacol ester onto the surface of gold nanoparticles (AuNPs). The detection of peroxynitrite is accomplished via measurement of the changes in the SERS spectra (at 882 cm?1) that are caused by the reaction between probe and peroxynitrite. The probe has a fast response (<30 s), a 0.4 μM lower detection limit and a wide linearity range from 5.0 × 10?7 to 1.0 × 10?4 M. It is biocompatible and highly stable on storage and under various pH conditions. Both the reaction and the SERS signal are highly specific over other species. The nanoprobe was successfully applied to SERS imaging of peroxynitrite that is produced in macrophages under oxidative stress. Conceivably, the method has a most viable tool for use in studies on peroxynitrite-related physiological and pathological processes.
关键词： Surface-enhanced Raman scattering,Boronate ester,Specific reaction,Reactive oxygen species,Gold nanoparticles,Living cell,Oxidative stress,Biosensor
更新于2025-09-23 15:19:57
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Catalysis by Visible Light Photoexcited Palladium Complexes
摘要： A new area of visible light-induced Pd-catalysis has been emerging into the field. In contrast to the classical ground-state Pd-catalyzed reactions mostly proceeding via two-electron redox manifold, the mechanisms for these new Pd-photoexcited methods usually operate via a single electron transfer process, thus leading to putative Pd-radical hybrid species, which exhibit both radical and classical Pd-type reactivity. This minireview highlights the recent progress in this rapidly growing area.
关键词： Visible light,Excited-state Pd-complex,Pd-radical hybrid species,Palladium
更新于2025-09-19 17:15:36
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Classification of Land Cover, Forest, and Tree Species Classes with ZiYuan-3 Multispectral and Stereo Data
摘要： The global availability of high spatial resolution images makes mapping tree species distribution possible for better management of forest resources. Previous research mainly focused on mapping single tree species, but information about the spatial distribution of all kinds of trees, especially plantations, is often required. This research aims to identify suitable variables and algorithms for classifying land cover, forest, and tree species. Bi-temporal ZiYuan-3 multispectral and stereo images were used. Spectral responses and textures from multispectral imagery, canopy height features from bi-temporal stereo imagery, and slope and elevation from the stereo-derived digital surface model data were examined through comparative analysis of six classification algorithms including maximum likelihood classifier (MLC), k-nearest neighbor (kNN), decision tree (DT), random forest (RF), artificial neural network (ANN), and support vector machine (SVM). The results showed that use of multiple source data—spectral bands, vegetation indices, textures, and topographic factors—considerably improved land-cover and forest classification accuracies compared to spectral bands alone, which the highest overall accuracy of 84.5% for land cover classes was from the SVM, and, of 89.2% for forest classes, was from the MLC. The combination of leaf-on and leaf-off seasonal images further improved classification accuracies by 7.8% to 15.0% for land cover classes and by 6.0% to 11.8% for forest classes compared to single season spectral image. The combination of multiple source data also improved land cover classification by 3.7% to 15.5% and forest classification by 1.0% to 12.7% compared to the spectral image alone. MLC provided better land-cover and forest classification accuracies than machine learning algorithms when spectral data alone were used. However, some machine learning approaches such as RF and SVM provided better performance than MLC when multiple data sources were used. Further addition of canopy height features into multiple source data had no or limited effects in improving land-cover or forest classification, but improved classification accuracies of some tree species such as birch and Mongolia scotch pine. Considering tree species classification, Chinese pine, Mongolia scotch pine, red pine, aspen and elm, and other broadleaf trees as having classification accuracies of over 92%, and larch and birch have relatively low accuracies of 87.3% and 84.5%. However, these high classification accuracies are from different data sources and classification algorithms, and no one classification algorithm provided the best accuracy for all tree species classes. This research implies the same data source and the classification algorithm cannot provide the best classification results for different land cover classes. It is necessary to develop a comprehensive classification procedure using an expert-based approach or hierarchical-based classification approach that can employ specific data variables and algorithm for each tree species class.
关键词： classification,ZiYuan-3,stereo image,machine learning,tree species
更新于2025-09-19 17:15:36
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Ferrocene Linkage Facilitated Charge Separation in Conjugated Microporous Polymers
摘要： Conjugated microporous polymers (CMPs) have full access to the organic synthesis toolbox and feature-rich functionality, structural diversity, and high surface area. We incorporated ferrocene (Fc) into the backbones of CMPs and systematically engineered their optical energy gaps. Compared with the CMPs without Fc units yet adopting similar molecular orbital level, Fc-based CMPs can sufficiently generate reactive oxygen species (ROS) under visible light. The resultant ROS are able to effectively decompose the absorbed pollutants, including organic dyes and chemical warfare agents. Specifically, Fc-based CMPs significantly outperform commercial TiO2 (P25) in the degradation of methylene blue and are capable of converting 2-chloroethyl ethyl sulfide (a mustard gas simulant) into completely nontoxic product.
关键词： conjugated microporous polymer,charge separation,photocatalytic degradation,ferrocene,reactive oxygen species
更新于2025-09-19 17:15:36
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A highly selective and sensitive fluorescent probe for simultaneously distinguishing and sequentially detecting H <sub/>2</sub> S and various thiol species in solution and in live cells
摘要： A novel dual-channel fluorescent probe (NCR) based on differences in reactivity among H2S, Cys/Hcy, and GSH was rationally designed for simultaneously distinguishing and sequentially sensing H2S, Cys/Hcy, and GSH using two emission channels, which also demonstrated that NCR can be used for targeting mitochondria in mammalian cells.
关键词： live cells,thiol species,fluorescent probe,mitochondria-targeted,H2S
更新于2025-09-19 17:15:36
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Rapid identification of wood species by near-infrared spatially resolved spectroscopy (NIR-SRS) based on hyperspectral imaging (HSI)
摘要： Conventional near-infrared (NIR) spectroscopy has shown its potential to separate wood species non-destructively based on the aggregate effect of light absorption and scattering values. However, wood has an aligned microstructure, and there is a large refractive index (RI) mismatch between the wood cell wall substance (n≈1.55) and the cell lumen (air≈1.0, water≈1.33). Light scattering is dominant over absorption μ′ (cid:31)( ) a in wood, and this fact can be utilized for complex classification purposes. In this study, an NIR hyperspectral imaging (HSI) camera combined with one focused halogen light source (? 1 mm) was designed to evaluate the light scattering patterns of five softwood (SW) and 10 hardwood (HW) species in the wavelength range from 1002 to 2130 nm. Several parameters were combined to improve the data quality, such as image histogram plots of defined spaced bins (associated with diffuse reflectance values of light), variance calculation on the frequency (the number of pixels in each bin) of each histogram and the principal component analysis (PCA) of all the variance values at each wavelength. The identification accuracy of the quadratic discriminant analysis (QDA) under the five-fold cross-validation method was 94.1%, based on the first three principal component (PC) scores.
关键词： spatially resolved spectroscopy,light scattering characteristics,wood species identification,hardwood,quadratic discriminant analysis (QDA),near-infrared hyperspectral imaging camera,principal component analysis (PCA),softwood,halogen spot-light source
更新于2025-09-19 17:15:36
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Photoinactivation of planktonic and biofilm forms of Escherichia coli through the action of cationic zinc(II)phthalocyanines
摘要： Novel water soluble Zn(II)phthalocyanines (ZnPc) peripherally substituted with 4-dimethylaminopyridine (DMAP) units (ZnPc 1-2) and the corresponding quaternized derivatives (ZnPc 1a-2a) were synthesized and their photodynamic inactivation (PDI) efficiency against a Gram-negative bacterium, a recombinant bioluminescent Escherichia coli strain either in planktonic and biofilm form was investigated. The analysis of the photophysical properties revealed that the increase in the number of DMAP units on ZnPc shifted the absorption and emission band in aqueous media to red. The presence of multi-positive charges on ZnPc derivatives prevented aggregation and enhances the solubility in aqueous medium. The quaternized derivatives ZnPc 1a and 2a displayed good stability and promising efficacy to generate singlet oxygen (1O2). The affinity of the amphiphilic ZnPc 1-2 and quaternized ZnPc 1a-2a to planktonic bacterial cells corresponded to an average uptake of ~106 PS molecules.CFU-1. The PDI assays conducted with planktonic cells and biofilms of E. coli show that irradiation with red or white light (150 mW.cm-2) in the presence of 20 μM of ZnPc derivatives caused an effective inactivation. ZnPc 1a and ZnPc 2a exhibited the highest inactivation efficiency, particularly of the planktonic form, causing 5 log (99.99%) reductions in bioluminescence. The inactivation factor for biofilms was 99% (2 log). ZnPc 1a and ZnPc 2a can be regarded as promising photosensitizers for the photodynamic inactivation of Gram-negative bacteria.
关键词： Reactive Oxygen Species,Cationic Phthalocyanines,E. coli,Bacterial Resistance,Biofilm,Antimicrobial Photoinactivation
更新于2025-09-19 17:15:36
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The construction and modulation of photoelectric functional hierarchical materials based on ionic self-assembly
摘要： The photoelectric functional hierarchical materials have been successfully prepared by the simple ionic self-assembly (ISA) strategy from the cationic ferrocenyl surfactant, 16-alkyl (ferrocenyl-methyl)ammonium bromide (Fc16AB) and the anionic alizarin red (AR). The obtained complexes exhibited multiple stimuli-responsive switching behaviour triggered by β-cyclodextrin (β-CD) inclusion, redox species, and pH. The switching mechanism corresponding to each stimulus was studied in detail. Moreover, the fluorescent intensity of binary complexes could be modulated by the concentration of Fc16AB and redox of ferrocene part. The fluorescence switching mechanism upon redox stimulus was studied in detail. Both the complexes fabrication and transition mechanisms were found to be controlled by the inclusion equilibrium and the cooperative binding of non-covalent interactions, including the electrostatic interactions, π-π stacking, and amphiphilic hydrophobic association. This work provides a deep understanding of electro-photo molecular switching device.
关键词： Hierarchical materials,pH,Redox species,Stimuli-responsive,β-Cyclodextrin (β-CD) inclusion,Ionic self-assembly
更新于2025-09-19 17:15:36
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Small but powerful: Light-emitting diodes for inactivation of Aspergillus species in real water matrices
摘要： This study addressed the effectiveness of light emitting diodes to achieve inactivation of three different Aspergillus species (Aspergillus fumigatus, Aspergillus niger and Aspergillus terreus) in a real water matrix. Three single small ultraviolet-C diodes emitting light at two different wavelengths were tested: 255 nm that is similar to the wavelength emitted by low pressure mercury lamps and 265 nm that is closer to the maximum absorbance wavelength of DNA. The ultraviolet-C diodes emitting light at 265 nm were found to be more effective than the 255 nm, achieving 3-log, 1-log and 5-log inactivations of Aspergillus fumigatus, Aspergillus niger and Aspergillus terreus using less than 20 mJ/cm2 (13,97 mJ/cm2; 7,28 mJ/cm2; 19,74 mJ/cm2). The diodes have also affected the morphology of the fungal spores and increased the percentage of damaged and dead spores.
关键词： Aspergillus species,Membrane permeability,Enzymatic activity,Light emitting diodes,Spores morphology,Disinfection
更新于2025-09-19 17:13:59