Search results for "Toe"

EPR investigations of polymeric and H2O2 -modified C3N4 -based photocatalysts

2019

The C3N4 -based nanopowders prepared by thermal condensation of melamine (MCN) with subsequent thermal etching (MCN-TE) and H2O2 -treatment were investigated by Q- and X-band EPR spectroscopy in dark and upon in situ UVA or visible-light exposure. Lorentzian signal at g = 2.003, more pronounced in the case of the thermally etched material, dominates EPR spectra of MCN and MCN-TE. More complex spectra were found for H2O2 -treated photocatalysts revealing the presence of signals attributed to the radicals produced via H2O2 interaction with C/N sites in the C3N4 polymeric network. The X-band spectra monitored upon in situ irradiation of the C3N4 -based photocatalysts evidenced the intensity gr…

Morphology controlled nano-structures of an octa(phenoxy)-substituted phthalocyaninato zinc complex: solvent effect on the self-assembly behaviour

2014

The 2,3,9,10,16,17,24,25-octakis(phenoxy)phthalocyaninato zinc, (Zn[Pc(OPh)8]) was fabricated into nano-/micro-structures via solution-phase self-assembly. The self-assembling properties of Zn[Pc(OPh)8] in coordinating and non-coordinating solvents (methanol and n-hexane) have been comparatively studied by electronic absorption, fluorescence, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. The conducting properties were evaluated by current–voltage (I–V) measurements. Due mainly to the presence of different intermolecular Zn–O coordination interactions between the Zn[Pc(OPh)…

2020

Recommender systems are information software that retrieves relevant items for users from massive sources of data. The variational autoencoder (VAE) has proven to be a promising approach for recommendation systems, as it can explore high-level user-item relations and extract contingencies from the input effectively. However, the previous variants of VAE have so far seen limited application to domain-specific recommendations that require additional side information. Hence, The Ensemble Variational Autoencoder framework for recommendations (EnsVAE) is proposed. This architecture specifies a procedure to transform sub-recommenders’ predicted utility matrix into interest probabilities that allo…

Preface to Special Issue of Energy Technology on Perovskite Optoelectronics

2017

This Editorial introduces one of two companion Special Issues on “Halide Perovskites for Optoelectronics Applications” in Energy Technology and ChemSusChem following the ICMAT 2017 Conference in Singapore. More information on the other Special Issue can be found in the Editorial published in ChemSusChem.

Tribovoltaic Device Based on the W/WO3 Schottky Junction Operating through Hot Carrier Extraction

2021

Estrogenic effects of food wrap packaging xenoestrogens and flavonoids in female Wistar rats : a comparative study

2003

International audience; The objective of this study was to compare the estrogenicity of xenoestrogens found in food wrap packaging and phytoestrogen flavonoids. Uterotrophic and vaginal cornification assays were performed on immature and ovariectomized rats. Genistein, bisphenol F, and octylphenol were identified as estrogenic only in immature rats. Using vaginal cornification as a more specific estrogenic parameter, all tested compounds except tangeretin were active in immature rats. While apigenin and kaempferol appeared to have low estrogenic activity, they potentialized the uterotrophic effect of 17β-estradiol in immature rats. These data showed that (i) phytoestrogens like genistein ca…

Isoflavonoid-based bone-sparing treatments exert a low activity on reproductive organs and on hepatic metabolism of estradiol in ovariectomized rats

2007

International audience; The use of soy isoflavones is a potential alternative to hormone replacement therapy in post-menopausal bone-loss prevention. Nevertheless, phytoestrogens can target other organs and may disrupt cell proliferation, or could modify endogenous steroid hormone metabolism. These mechanisms could be linked to an increased risk of developing cancer. We therefore studied the possible side effects of such treatments in an experimental model of menopause. Forty adult female Wistar rats were ovariectomized and fed with a genistein-, daidzein- or equol-supplemented diet at bone-sparing levels (10 mg/kg BW/day) for 3 months. The estrogenic effects were assessed by histological a…

Transforming Tradition: Richard Courant in Göttingen

2018

Richard Courant had a knack for being at the right place at the right time. He came to Gottingen in 1907, just when Hilbert and Minkowski were delving into fast-breaking developments in electron theory. There he joined three other students who also came from Breslau: Otto Toeplitz, Ernst Hellinger, and Max Born, all three, like him, from a German Jewish background. Toeplitz was their natural intellectual leader, in part because his father was an Oberlehrer at the Breslau Gymnasium (Muller-Stach 2014). Courant was five or six years younger than the others; he was sociable and ambitious, but also far poorer than they (Reid 1976, 8–13).

EXCITONS, LOCALIZED STATES IN SILICON DIOXIDE AND RELATED CRYSTALS AND GLASSES

2000

The excitons, localized states in crystalline and glassy silicon dioxide, germanium dioxide were studied by photoluminescent and photoelectric experimental methods. Results were compared with analogous investigations of related crystals, such as aluminum and gallium orthophosphates, and of related glasses, such as silica, sodium silicates, germanates, lead and phosphates glasses. Special attention was made to the influence of oxygen deficiency on localized states of glasses, in general, and to the nature of the 7.6 eV band in reduced silica, in particular.

Generalist invasion in a complex lake food web

2023

Invasive species constitute a threat not only to native populations but also to the structure and functioning of entire food webs. Despite being considered as a global problem, only a small number of studies have quantitatively predicted the food web-level consequences of invasions. Here, we use an allometric trophic network model parameterized using empirical data on species body masses and feeding interactions to predict the effects of a possible invasion of Amur sleeper (Perccottus glenii), on a well-studied lake ecosystem. We show that the modeled establishment of Amur sleeper decreased the biomasses o ftop predator fishes by about 10%–19%. These reductions were largely explained by inc…