Novel fluorescent main-chain liquid crystalline ionomers containing Eu(III) ions

<p>Novel nematic fluorescent main-chain liquid crystalline ionomers containing Eu(III) ions (Eu-LCI) were synthesised by the use of bis(4-(chlorocarbonyl)phenyl) decanedioate (BD), 4,4-dihydroxybiphenyl (D), 2,5-dihydroxybenzoic acid (B) and anhydrous europium chloride. The chemical structures, liquid crystalline behaviours and fluorescence properties of Eu-LCI were characterised by various experimental techniques. The introduction of small amounts of europium ions endowed the LCI with excellent luminescence properties. POM results showed that europium ions did not change the liquid crystalline texture of the LCI. Fourier transform infrared imaging showed that europium ions were evenly distributed in the matrices of ionomers. A schematic diagram of nematic fluorescent LCI was established to demonstrate the interaction and distribution of the components. Eu-LCI showed reversible mesomorphic phase transitions, wide mesophase temperature ranges and high thermal stability. The thermogravimetric analysis (TGA) results showed that decomposition temperatures (5% weight loss) were greater than 308°C in all Eu-LCI. Eu-LCI can emit red light when excited. The luminescence intensity of Eu-LCI gradually increased with increase in Eu(III) ions from 0.3 to 1.5 mol%. The temperature dependence of luminescent intensity was studied in the liquid crystalline phase, where the fluorescence intensity of Eu-LCI decreased monotonically with increase in temperature.</p

Luminescent Iridium-containing liquid crystalline polymers in the side chain

<p>Luminescent liquid crystalline polymers consisting of Iridium attached to polysiloxanes are prepared. 4-Cyanophenyl 4-(allyloxy) benzoate (M₁) and an Iridium complex (Ir-M₂) grafted to poly(methylhydrogeno)siloxane are used for the preparation of the Iridium-containing liquid crystalline polymers. The chemical structures are characterised by Fourier transform infrared spectroscopy and ¹H NMR. The mesomorphic properties and phase behaviour are investigated by differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy and X-ray diffraction. The polymers containing <1.2 mol% of the Iridium ions reveal reversible mesomorphic phase transition, wide mesophase temperature ranges and high thermal stability. The introduction of the Iridium ions does not change the liquid crystalline state of polymer systems; on the contrary, the polymers are enabled with the luminescent properties. With the Iridium ion contents ranging between 0.3 and 1.2 mol%, luminescent intensity of polymers gradually increased. The temperature dependence of luminescent intensity was studied in the liquid crystalline phase.</p

Preparation of highly exfoliated epoxy/clay nanocomposites by clay grafted with liquid crystalline epoxy

<p>Epoxy/clay nanocomposites with a high degree of exfoliation were achieved by intercalating liquid crystalline epoxy into clay intragallery as well as using a so-called ‘solution compounding’ process. In this process, clay modified was first treated with trichloromethane to form organoclay-trichloromethane suspension followed by liquid crystalline epoxy modification. The liquid crystalline epoxy grafted clay was then mixed extensively with epoxy to form epoxy/nanoclay composites. The mechanism of exfoliation was explored by monitoring the change of morphology of organoclay during each stage of processing with X-ray diffraction (XRD). The liquid crystalline epoxy grafted clay synthesised was characterised by fourier transform infrared spectroscopy (FT-IR) and polarising optical microscopy (POM). The clay platelets uniformly dispersed and highly exfoliated in the whole epoxy matrix were observed using transmission electron microscopy (TEM) and FT-IR imaging system. The epoxy nanocomposites were fabricated by incorporating different liquid crystalline epoxy grafted clay loading. The results revealed that the incorporation of liquid crystalline epoxy grafted clay resulted in a significant improvement in glass transition temperature (Tg) derived from dynamic mechanical analysis (DMA) and thermal stability measured by thermogravimetric analysis (TGA).</p

Mesomorphic and luminescence properties of side chain cholesteric liquid crystalline polymers containing Eu(III) and Tb(III) ions

<div><p>Luminescent cholesteric liquid crystalline polymers consisting of the lanthanide ions covalently attached to cholesteric polysiloxanes are prepared. Cholesteric liquid crystalline monomer and 4-(allyloxy)benzoic acid grafted to poly(methylhydrogeno)siloxane is used as one of the precursors for the preparation of the lanthanide-containing cholesteric liquid crystalline polymers. The chemical structures of the monomers are characterised by Fourier transform infrared, ¹H NMR and elemental analyses. The mesomorphic properties and phase behaviour are investigated by differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy and X-ray diffraction. The polymers containing <3 mol% of the lanthanide ions reveal reversible mesomorphic phase transition, wide mesophase temperature ranges and high thermal stability. The introductions of the lanthanide ions do not change the liquid crystalline state of polymer systems; on the contrary, the polymers are enabled with the significant luminescent properties. With the lanthanide ions contents ranging between 1 and 3 mol%, luminescent intensity and luminescent lifetimes of polymers gradually increased. The temperature dependence of luminescent intensity was studied in the liquid crystalline phase.</p></div

Brusatol treated results in abnormal spindles and chromosome organization defects.

<p>A) Oocytes at MII stage were immunostained with α -tubulin antibody to visualize spindle (green) and counterstained with Hoechst 33342 for chromosomes (blue). Representative confocal images showing the spindle morphology and chromosome alignment in control (a) and Brusatol treated (b-c) oocytes. Arrowheads indicate the abnormal spindle and arrows indicate the misaligned and decondensed chromosomes. B) Quantification of control, Brusatol treated and Brusatol+Nrf2-plasmid treated oocytes with spindle/chromosome defects. Data are expressed as mean percentage ± SD from three independent experiments in which at least 120 oocytes were analyzed. Scale bar, 20 μm. *p < 0.05.</p

The toxic effects and possible mechanisms of Brusatol on mouse oocytes

<div><p>Brusatol is a natural quassinoid that shows a potential therapeutic use in cancer models by the inhibition of Nuclear factor erythroid 2-related factor 2 (Nrf2) and is capable of inducing a variety of biological effects. The effects of Brusatol on oocyte meiosis has not been addressed. In this study, we investigated the impact of Brusatol treatment on mouse oocyte maturation and its possible mechanism. Our data demonstrated that Brusatol treatment disrupted oocyte maturation and spindle/chromosome organization by modulating Nrf2-Cyclin B1 pathway, as the influence of Brusatol was compensated by the addition of Nrf2 activation plasmid, and the mRNA and protein levels of Cyclin B1 were severely reduced in oocytes following Nrf2 decline. In summary, our data support a model that Brusatol, through the inhibition of Nrf2, modulate Cyclin B1 levels, consequently disturbing proper spindle assembly and chromosome condensation in meiotic oocytes.</p></div

Effects of Brusatol on mouse oocyte maturation.

<p>A) Quantitative analysis of GVBD and Pb1 extrusion in different treatment groups (control, 20 nM, 50 nM, 100 nM, 200 nM and 1000 nM). B) Polar body extrusion failure after Brusatol treated. Images were acquired with a camera on a stereomicroscope. Arrows showed that the control oocytes extruded the polar body while the treated oocytes failed. Scale bar, 100 μm. *p < 0.05 vs controls.</p

Simple and Efficient Green-Light-Emitting Diodes Based on Thin Organolead Bromide Perovskite Films via Tuning Precursor Ratios and Postannealing Temperature

Organometal halide perovskites (OHPs) are becoming a hot topic in the field of display and lighting. Unlike the strategy used for solar cells, that is, using several hundred nanometers thick OHP film for fully absorbing solar light to convert electricity, thin-film OHPs (<50 nm) are advantageous to restrain its self-absorption drawback and thus beneficial for preparing efficient light-emitting diodes (LEDs). Here we manipulate the excess molar ratio of MABr/PbBr₂ precursors and the post-annealing temperature to obtain uniform thin-film OHPs and suppress the nonradiative defects. Using this simple process, high efficient green perovskite light-emitting diode (PeLED) was obtained, with a maximum luminance of 6124 cd m^–2, current efficiency of 15.26 cd A^–1, and external quantum efficiency of 3.38%, which is nearly three-fold enhancement with respect to the previous reported best PeLED based on thin perovskite films (<50 nm

Brusatol reduces cyclin B1 expression in oocytes.

<p>A) The relative mRNA level of cyclin B1 was determined by qRT-PCR in control and Brusatol treated oocytes. mRNA level in control oocytes were set as 1. B) Oocytes at MI stage were immunostained with cyclin B1 antibody (green) and counterstained with Hoechst 33342 for chromosomes (blue). C) Western blot showing decline of cyclin B1 after Bruastol treatment with actin as a loading control. C) Western blot showing increase of cyclin B1 after Nrf2 overexpression with actin as a loading control. Error bars indicate ± sd Scale bar, 20 μm. *p < 0.05.</p

Effects of saturated palmitic acid and omega-3 polyunsaturated fatty acids on Sertoli cell apoptosis

<p>Obesity is believed to negatively affect male semen quality and is accompanied by dysregulation of free fatty acid (FFA) metabolism in plasma. However, the implication of dysregulated FFA on semen quality and the involvement of Sertoli cells remain unclear. In the present study, we report obesity decreased Sertoli cell viability through dysregulated FFAs. We observed an increased rate of apoptosis in Sertoli cells, accompanied with elevated FFA levels, in the testes of obese mice that were provided a high-fat diet (HFD). Moreover, the levels of reactive oxygen species were elevated. Furthermore, we demonstrated by <i>in vitro</i> assays that saturated palmitic acid (PA), which is the most common saturated FFA in plasma, led to decreased cell viability of TM4 Sertoli cells in a time- and dose-dependent manner. A similar finding was noted in primary mouse Sertoli cells. In contrast to saturated FFA, omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) protected Sertoli cells from PA-induced lipotoxicity at the physiologically relevant levels. These results indicated that the lipotoxicity of saturated fatty acids might be the cause of obesity-induced Sertoli cell apoptosis, which leads to decreased semen quality. In addition, ω-3 PUFAs could be classified as protective FFAs.</p> <p><b>Abbreviations:</b> FFA: free fatty acid; HFD: high-fat diet; SD: standard diet; PA: palmitic acid; PUFA: polyunsaturated fatty acid; AI: apoptotic index; MTT: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide; ROS: reactive oxygen species; HE: Hematoxylin and eosin; WT1: Wilm Tumor 1; NAFLD: non- alcoholic fatty liver disease; DCFH-DA: 2ʹ, 7ʹ dichlorofluorescin diacetate; 36B4: acidic ribosomal phosphoprotein P0; SD: standard deviation; EPA: eicosapentaenoic acid; PI: propidium iodide; DHA: docosahexenoic acid.</p