RESUMO
With the increasing spectral dimension of hyperspectral images (HSI), how correctly choose bands based on band correlation and information has become more significant, but also complicated. Band selection is a combinatorial optimization problem, and intelligent optimization algorithms have been shown to be crucial in solving combinatorial optimization problems. However, major of them only use a single objective as the selection index, while neglecting the overall features of hyperspectral images, which may lead to inaccuracy in object detection. To tackle this, we propose a band selection method based on a multi-objective cuckoo search algorithm (MOCS) when constructing a multi-objective unsupervised band selection model based on the amount of information and correlation of the bands (MOCS-BS). Specifically, an adaptive strategy based on population crowding degree is first proposed to assist Lévy flight in overcoming the influence of the parameter constancy. Then, an information-sharing strategy based on grouping and crossover is designed to balance the search ability between global exploration and local exploitation, which can overcome the shortcomings caused by the lack of information interaction between individuals. Finally, the HSI classification experiments are performed by Random Forest and KNN classifiers based on the subset of bands selected by the proposed MOCS-BS method. The proposed method is compared with state-of-the-art algorithms including neighborhood grouping normalized matched filter (NGNMF) and multi-objective artificial bee colony with band selection (MABC-BS) on four HSI datasets. The experimental results demonstrate that MOCS-BS is more effective and robust than other methods.
RESUMO
A novel supramolecular gel is synthesized using styrene and halloysite nanotubes under ultrasound treatment, in which the nanotubes act as gelators for the styrene gel. The formation of the gel arises from electron-transfer reactions between styrene and the aluminium atoms at the crystal edges and the transition metal ions of the clay. The supramolecular gel is transparent and sensitive to temperature, which shows promising applications in sensors, templates, and gelling fuels.
RESUMO
Because of their outstanding properties, increasing numbers of research studies and emerging applications for manufacturing products are currently in progress for halloysite nanotubes (HNTs). Therefore, the impact of HNTs on the environment and human health should be taken into consideration. In order to clearly show the cell uptake of HNTs and the biodistribution of HNTs in zebrafish, HNTs are labeled with fluorescein isothiocyanate (FITC-HNTs). The cytotoxicity assays showed that the cell viabilities of human umbilical vein endothelial cells (HUVECs) and human breast adenocarcinoma (MCF-7) cells were above 60% after being treated with different concentrations of HNTs (2.5-200 µg mL-1) for 72 h. Confocal laser scanning microscopy (CLSM) results showed the uptake of HNTs by HUVECs and MCF-7 cells. The in vivo toxicity of HNTs was then investigated in the early development of zebrafish embryos. The percent survival of zebrafish embryos and larvae showed no significant changes at different developmental stages (24, 48, 72, 96, and 120 hpf) when treated with various concentrations of HNTs (0.25-10 mg mL-1). Besides, HNTs could promote the hatchability of zebrafish embryos and did not affect the morphological development of zebrafish at a concentration of ≤25 mg mL-1. HNTs could also be ingested by zebrafish larvae and accumulated predominantly in the gastrointestinal tract. The fluorescence intensity of FITC-HNTs decreased gradually with time, which suggested that HNTs could be excreted by zebrafish larvae through the gastrointestinal metabolism. Therefore, it can be concluded that HNTs are relatively biocompatible nanomaterials, which can be utilized in many fields.
