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Organic and polymer fluorescent nanomaterials are a frontier research focus. Here in this work, a series of fluorinated zwitterionic random copolymers end‐attached with a quasi‐chromophoric group of pyrene or tetraphenylethylene (TPE) are well synthesized via atom transfer radical polymerization with activators regenerated by electron transfer (ARGET ATRP). Those random copolymers with total degree of polymerization 100 or 200 are able to produce fluorescent single‐chain nanoparticles (SCNPs) through intra‐chain self‐folding assembly with quite uniform diameters in the range of 10–20 nm as characterized by dynamic light scattering and transmission electron microscopy. By virtue of the segregation or confinement effect, both SCNPs functionalized with pyrene or TPE group are capable of emitting fluorescence, with pyrene tethered SCNPs exhibiting stronger fluorescence emission reaching the highest quantum yield ≈20%. Moreover, such kind of fluorescent SCNPs manifest low cytotoxicity and good cell imaging performance for Hela cells. The creation of fluorescent SCNPs through covalently attached one quasi‐chromophore to the end of one fluorinated zwitterionic random copolymer provides an alternative strategy for preparing polymeric luminescence nanomaterials, promisingly serving as a new type of fluorescent nanoprobes for biological imaging applications. [ABSTRACT FROM AUTHOR]

Leaf Area Index (LAI) is one of the most important biophysical parameters of vegetation, and its dynamic changes can be used as a reflective indicator and differentiation basis of vegetation function. In this study, a VCA–MLC (Vertex Component Analysis–Maximum Likelihood Classification) algorithm is proposed from the perspective of multi-temporal satellite LAI image classification to monitor and quantify the spatial and temporal variability of vegetation dynamics in China since 2000. The algorithm extracts the vegetation endmembers from 46 multi-temporal images of MODIS LAI in 2011 without the aid of other a priori knowledge and uses the maximum likelihood classification method to select the categories that satisfy the requirements of the number of missing periods, absolute distance, and relative distance for the rest pixels to be classified, ultimately dividing the vegetation area of China into 10 vegetation zones called China Vegetation Functional Zones (CVFZ). CVFZ outperforms MCD12Q1 and CLCD land cover datasets in the overall differentiation of vegetation functions and can be used synergistically with other land cover datasets. In this study, CVFZ is used to cut the constant vegetation-type pixels of MCD12Q1 during 2001–2022. The results of the LAI mean time series decomposition of each subregion using the STL (Seasonal-Trend Decomposition based on Loess) method show that the rate of vegetation greening ranges from 9.02 × 10−4 m2m−2yr−1 in shrubland subregions to 2.34 × 10−2 m2m−2yr−1 in savanna subregions. In relative terms, the average greening speed of forests is moderate, and savannas tend to have the fastest average greening speed. The greening speed of grasslands and croplands in different zones varies widely. In contrast, the average greening speed of shrublands is the slowest. In addition, CVFZ detected grasslands with one or two phenological cycles, broadleaf croplands with one or two phenological cycles, and shrublands with no apparent or one phenological cycle. [ABSTRACT FROM AUTHOR]

Thermotropic ionic liquid crystals (ILCs) are a kind of fascinating functional organic material combining the characteristics and advantages of both liquid crystals (LC) and ionic liquids. Here in this work, a series of supramolecular discotic ILCs of Cn-tri-CTP have been produced through host–guest complexation together with π–π stacking and electrostatic interactions between the readily prepared electrically neutral tris(18-crown-6)triphenylene (tri-CTP) and the facilely available potassium trialkoxybenzenesulfonates with different length alkyl tails of carbon number n = 8, 10, 12, 14, 16. The thus obtained ILC complexes show enantiotropic ordered columnar mesophases, such as center-faced rectangular columnar (Colr) and oblique columnar (Colob) mesophases with broad LC temperature ranges and excellent thermal stability. It is very interesting and fascinating to find that after a simple alignment, such supramolecular discotic ILC complexes in their ordered columnar structures achieve simultaneously anisotropic ionic conductivities as high as 1.99 × 10−2 S cm−1 and hole mobility reaching 4.6 × 10−2 cm2 V−1 s−1, thus exhibiting fantastic dual-channel transport properties both for ions and holes, which may develop into a kind of versatile organic electronic material for various promising unique applications. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomers (LCEs) combine the ordering character of a liquid crystal and the elasticity of a polymer network. The development of fully light-driven LCE-based soft actuators with good reshapeability and recyclability is in high demand. In this work, we prepared SWCNT/LCE composite films through the introduction of allyl sulfide-based dynamic covalent crosslinks in the LCE matrix and the well-dispersed filler single-walled carbon nanotubes (SWCNTs) with a strong photothermal effect. The SWCNT/LCE composite films were facilely fabricated with reorientation and remouldable capabilities regulated by 405 nm visible light. The monodomain composite films demonstrated multimode actuations of contraction, bending, curling, stretching recovery, and even shape memory driven by 808 nm near-infrared (NIR) light. Moreover, the monodomain spiral ribbon or stretching flat strip and the original polydomain composite film can be readily transformed into each other, and reshaped through easily achievable fabrication conditions. Therefore, the well-prepared SWCNT/LCE composite films with exchangeable covalent crosslinks showed promise as candidates for the development of multimode NIR photomechanical soft actuators with fully light-driven controllability and good remouldability. [ABSTRACT FROM AUTHOR]

The design and preparation of novel liquid crystalline elastomers (LCEs) are highly desirable for the development of smart soft materials with quick stimuli-responsive characteristics. In this work, we present a facile preparation strategy of near infrared (NIR)-responsive gold nanorod/liquid crystalline elastomer (GNR/LCE) composite films exhibiting fascinating re-shapeable and reusable properties. A random side-chain liquid crystalline copolymer containing biphenyl mesogens and cinnamate side groups has been prepared via ring-opening metathesis polymerization (ROMP), with the [2+2] (retro)cycloaddition of cinnamate groups triggered by various wavelength UV light serving as the reversible dynamic crosslinks for the construction of re-shapeable LCEs. The GNR/LCE composite films with uniformly doped monodisperse GNRs demonstrate remarkable photothermal effects and multi-mode NIR-driven macroscopic deformation capabilities. Furthermore, a single-layer dual-phase composite film composed of periodic micro-patterned monodomain (M) and polydomain (P) structures has been fabricated, which is promising for precise localized NIR-responsive actuation and fully photo-controlled LCE composite devices. [ABSTRACT FROM AUTHOR]

Abstract Microcystin-leucine-arginine (MC-LR), as a most common and deleterious variant among all structural analogues of Microcystins (MCs), can cause male reproductive dysfunction. However, its toxic effects on prostate in adult mice have not been invested in detail. In this study, we observed that MC-LR could enter prostate tissues and induce focal hyperplasia and prostate inflammation. Moreover, increased levels of prostate specific antigen (PSA) and prostate acid phosphatase (PAP) in serum of mice following chronic exposure to MC-LR were detected. We also examined increased expression of forkhead box protein M1 (FOXM1) and PSA in human prostate epithelial cells (RWPE-1) treated with MC-LR at low levels, and FOXM1 could regulate PSA expression. Furthermore, MC-LR also induced expression of CyclinD1 via FOXM1/Wnt/β-catenin signaling pathways in RWPE-1 cells, promoting proliferation of prostate epithelial cells, resulting in prostatic hyperplasia in vivo. As a foreign substance, MC-LR also induced immune reaction in RWPE-1 cells mediated by NF-κB pathway, promoting production of pro-inflammatory cytokines and chemokines. Collectively, these findings demonstrated that MC-LR may induce prostatic hyperplasia and prostatitis in mice following chronic low-dose exposure to MC-LR. This work may provide new perspectives in developing new diagnosis and treatment strategies for MC-LR-induced prostatic toxicity. Graphical abstract Image 1 Highlights • MC-LR promotes proliferation of prostate epithelial cells in vivo. • MC-LR induces increased levels of PSA, PAP and pro-inflammatory cytokines in serum and prostate tissues. • FOXM1/Wnt/β-catenin pathway is involved in overexpression of CyclinD1 to promote proliferation of RWPE-1 cells. • MC-LR induces immune reactions in prostate epithelial cells. Chronic exposure to microcystin-LR induced benign prostatic hyperplasia. [ABSTRACT FROM AUTHOR]

Abstract: Through the construction of an organic photocatalysis system, photoredox catalyst (PC)/additive, where PC stands for photoredox catalyst, an organocatalyzed step transfer‐addition and radical‐termination (O‐START) polymerization irradiated by blue LED light at room temperature is realized. Different types of α,ω‐diiodoperfluoroalkane A and α,ω‐unconjugated diene B are copolymerized through O‐START efficiently, and generate various kinds of functional semifluorinated polymers, including polyolefins and polyesters. The process is affected by several factors; solvents, additives, and feed ratio of A to B. After optimization of all these components, the polymerization efficiency is greatly improved, generating polymers with both relatively high yield and molecular weight. Considering the mild reaction condition, easy operation process, and free‐of‐metal‐catalyst residues in the polymer product, the organocatalytic polymerization strategy provides a simple and efficient approach to functional semifluorinated polymer materials and hopefully opens up their application in high‐tech fields. [ABSTRACT FROM AUTHOR]

A new polymerization method, termed as step transfer-addition and radical-termination, is developed for the step-growth radical polymerization of α,ω-unconjugated dienes under irradiation of visible light at room temperature (25 °C) for the first time. α,ω-Diiodoperfluoroalkane monomers (signified as A) are added onto α,ω-unconjugated dienes (signified as B) alternatively and efficiently with the generation of perfluorocarbon-containing alternating copolymers ( AB) n. Based on the combined analyses of polymerization kinetics and NMR spectra (1H and 19F), the mechanism of the novel polymerization method, including the side reaction, is proposed. This novel polymerization method provides a new strategy not only for the step-growth radical polymerization of α,ω-unconjugated dienes but also for the construction of high molecular weight perfluorocarbon-containing alternating copolymers. [ABSTRACT FROM AUTHOR]