During visual excitation, rhodopsin undergoes photoactivation and bleaches to opsin and all-trans-retinal. To regenerate rhodopsin and maintain normal visual sensitivity, the all-trans isomer must be metabolized and reisomerized to produce the chromophore 11-cis-retinal in biochemical steps that constitute the visual cycle and involve the retinal pigment epithelium (RPE; refs. 3-8). A key step in the visual cycle is isomerization of an all-trans retinoid to 11-cis-retinol in the RPE (refs. 9-11). It could be that the retinochrome-like opsins, peropsin, or the retinal G protein-coupled receptor (RGR) opsin12-16 are isomerases in the RPE. In contrast to visual pigments, RGR is bound predominantly to endogenous all-trans-retinal, and irradiation of RGR in vitro results in stereospecific conversion of the bound all-trans isomer to 11-cis-retinal. Here we show that RGR is involved in the formation of 11-cis-retinal in mice and functions in a light-dependent pathway of the rod visual cycle. Mutations in the human gene encoding RGR are associated with retinitis pigmentosa.
Organophilic Bentonite / Paraffin composite phase change energy storage materials (OB/P PCM composite) were prepared by melting intercalation method. Under high temperature, no melt paraffin seep out from the PCM of organophilic bentonite/paraffin (OB/P) mass ratio is 2:1, which paraffin content is largest. Samples were tested by X ray diffraction (XRD), Scanning Electron Microscope (SEM), Differential scanning calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). Paraffin was well intercalated into layerd bentonite. Melting point and fussion heat of composite PCM with mass ratio2:1 are 45.7 °C and 68.7 kJ/kg, it can be added to solar energy.
Based on X-ray diffraction results, the gallery height of modified Mg3Al-LDH was expanded to 9.6Å from the original 4.8Å, indicating that the H3PW12O40 was indeed inserted into the hydroxide layers. Moreover, the results of FT-IR spectra proved the Keggin structure of PW11O397- species. The resulting material showed a high activity of degradation of methyl orange in the presence of H2O2 and UV light irradiation.
Novel bio-composites were synthesized by plasma current activated sintering from the Ti-35Nb-2.5Sn/HA powders ball-milled for 12 h. The aim of this study was to investigate the effects of HA content (5, 10 and 15 wt%) on sintering properties, microstructure and compression properties of Ti-35Nb-2.5Sn/HA bio-composites. Results indicated that sintering rate decreased slightly with the increase of HA content. The phases of sintered composites were mainly˰ڂ˽̤̹˼˰̘̑˼˰Ca3(PO4)2(TCP), TiO2, CaTiO3and TixPy. The grain size of sintered composites reduced with the increasing of HA content, and sintered composites with ultra fine grains were fabricated finally. The compression test showed that all the sintered composites had low elastic modulus and high compression strength. The elastic modulus of Ti-35Nb-2.5Sn/15HA sintered composites was 22GPa with a high strength of 877MPa.
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