Effect of the sensitizer on the properties of fully functionalized photorefractive epoxy polymers and their performance in the hologram image

ABSTRACT: The 3-amino-9-ethyl carbazole (AEC)/Dispersed Orange 3 (DO3)/diglycidyl 1,2 cyclohexanedicarboxylate (DCD) main chain copolymers are synthesized and studied on their photorefractive (PR), photoconductive, and holographic characteristics. They are good hologram recording media because not only the stored hologram exhibits excellent fringe contrast with the resolution at about 20 m, but also the image can be stored, erased, and overwritten. The UV/Vis spectra shows that AEC segments may form charge transfer complexes with either DO3 segments or TNF sensitizers. By incorporating the sensitizer or increasing the charge transfer component concentration, the grating growth rate can be speeded up. Applying an electric field on the polymer film containing no sensitizer helps to elevate the grating growth speed, but it shows little influence on the grating growth speed of the films with sensitizers. More nonlinear optical (NLO) segments in the copolymer result in higher diffraction efficiency. The dark decay of the film depends on the dark conductivity. Incorporating sensitizers or more charge transport segments leads to more dark decay because of increasing dark conductivity. The dark decay of the PR properties at elevated temperature can also be evaluated by the thermal stimulated discharge current (TSDC) spectroscopy technique

Iron rescues glucose-mediated photosynthesis repression during lipid accumulation in the green alga Chromochloris zofingiensis

Energy status and nutrients regulate photosynthetic protein expression. The unicellular green alga Chromochloris zofingiensis switches off photosynthesis in the presence of exogenous glucose (+Glc) in a process that depends on hexokinase (HXK1). Here, we show that this response requires that cells lack sufficient iron (-Fe). Cells grown in -Fe+Glc accumulate triacylglycerol (TAG) while losing photosynthesis and thylakoid membranes. However, cells with an iron supplement (+Fe+Glc) maintain photosynthesis and thylakoids while still accumulating TAG. Proteomic analysis shows that known photosynthetic proteins are most depleted in heterotrophy, alongside hundreds of uncharacterized, conserved proteins. Photosynthesis repression is associated with enzyme and transporter regulation that redirects iron resources to (a) respiratory instead of photosynthetic complexes and (b) a ferredoxin-dependent desaturase pathway supporting TAG accumulation rather than thylakoid lipid synthesis. Combining insights from diverse organisms from green algae to vascular plants, we show how iron and trophic constraints on metabolism aid gene discovery for photosynthesis and biofuel production

Inhibitory Effects of the Aerial Parts of Epimedium koreanum on TPA-Induced Inflammation and Tumour Promotion in Two-Stage Carcinogenesis in Mouse Skin

Cancer prevention by supplements offers the most cost-effective long-term health strategy. Methanol extracts from the aerial parts of Epimediumkoreanum were previously found to inhibit 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammatory ear oedema and tumour promotion by TPA in the two-stage mouse skin carcinogenesis model. Four prenyl flavonol glycosides (14) were isolated from the active fraction of this extract, and were identified. The isolated compounds showed inhibitory activity against TPA-induced ear inflammatory ear oedema. The 50% inhibitory dose (ID50) of icariin (1), epimedin A (2), epimedin B (3) and epimedin C (4) for TPA-induced inflammation ranged from 114 to 255 nmol/ear, suggesting greater potency than indomethacin (ID50: 908 nmol/ear), an anti-inflammatory drug. Thus, the epimedium herb may be useful in cancer prevention

Inhibitory Effects of Ginseng (Panax ginseng) Berry on Tumour Promotion and Inflammatory Ear Oedema Induced by TPA

Cancer prevention is a major issue in the field of public health. Ethanol extracts of the ginseng berry were found to inhibit the inflammation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), a tumour promoter. The extracts also inhibited tumour promotion by TPA in the mouse skin two-stage carcinogenesis model. The major components, ginsenosides Rd (3) and Re (4), inhibited inflammation induced by TPA in mice, while protopanaxadiol (1) and protopanaxatriol (2), the aglycones of these ginsenosides, markedly inhibited TPA-induced inflammatory ear oedema in mice. The inhibitory effects of these compounds were more potent than those of indomethacin

The effects of serial stretch loading on stretch work and stretch- shorten cycle performance in the knee musculature

Training methods to optimize stretch-shorten cycle performance and an active muscle\u27s ability to resist a sudden stretch (stretch work) and the relationship between the two have not been fully explored. The purpose of this study was to examine the effects of an 8-week strengthening program of serial stretch loading on stretch work and stretch-shorten cycle performance in the quadriceps and hamstring muscles. Thirty-one asymptomatic subjects participated in pre- and post-tests of maximum voluntary isometric contractions, stretch work and stretch-shorten cycle trials, and single-leg vertical jumps. The training portion consisted of progressively resisted isotonic single-leg squats. One leg exercised against an isotonic load with serial stretch loading, while the other leg exercised against isotonic load alone. Training resulted in strength gains in both legs indicated by the increase in weight lifted during training, but not by maximum voluntary isometric contractions. Vertical jump height increased in both legs. In the hamstring, stretch work decreased and stretch-shorten cycle performance increased in both legs. In the quadriceps, serial stretch loading intervention resulted in increased stretch-shorten cycle performance and no significant change in stretch work. The correlation between stretch-shorten cycle and stretch work was weak but significant. These findings suggest that the use of serial stretch loading could improve muscular performance and enhance a muscle\u27s potential for dynamic stabilization