Search results for "Ether"
showing 10 items of 986 documents
Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability
2022
Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites’ electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes dur…
Gas chromatographic and mass spectrometric characterization of the organic acids extracted from some preparations containing lyophilized royal jelly.
2009
Thirty-five aliphatic acids were identified by gas chromatography-mass spectrometry from the ether extract of commercial preparations containing lyophilized royal jelly. The article presents linear-programmed retention indices on capillary columns with non-polar and low-polar stationary phases and mass spectra for identified compounds which were not characterized earlier by these parameters. Nine compounds are reported for the first time as royal jelly constituents.
Induction of Hsp70 by the Herbicide Oxyfluorfen (Goal) in the Egyptian Nile Fish, Oreochromis niloticus
1999
This paper deals with the expression of the biomarker hsp70 in the liver and kidney of the freshwater fish Oreochromis niloticus following exposure to the herbicide oxyfluorfen (Goal). Fishes were exposed to three concentrations, the 96-h LC50 (3 mg/L), the 96-h (1/2)LC50 (1.5 mg/L), and the 96-h (1/4)LC50 (0.75 mg/L) of oxyfluorfen for 6, 15, and 24 days, respectively, and samples were taken at three different time periods for each concentration. The livers responded to the herbicide by an induction of the expression of both the constitutive (hsp75; Mr 75 kDa) and the inducible (hsp73; Mr 73 kDa) hsp70 proteins. In kidney, the herbicide induced a time-dependent increase in the expression o…
¿Cabe hablar de una «generación de la crisis»? Discusión en torno a una noción sobreexplotada
2018
This article states that nowadays there is an overuse (or a misuse) of the «Generation» idea. The discussion among many authors over the «Generation of crisis» concept suggests that it is useful to outline the characteristics of the target of population of the collective of youth who are mainly affected by the economic and social crisis over the past years. Nevertheless, through analyzing the meanings of the «Generation of Crisis» made by Mannheim, Ortega and other classic authors, it is clear that the social class approach together with the generational one are needed to define this concrete concept. The conclusion of the articleis that both approaches are seen as underpinning their utilit…
Models as Research Tools: Plücker, Klein, and Kummer Surfaces
2018
In the late summer of 1869, 20-year-old Felix Klein made his way to Berlin, where he planned to attend the renowned seminar founded by Ernst Eduard Kummer and Karl Weierstrass. Klein had already taken his doctorate in Bonn and he would soon be recognized as a leading expert on line geometry, a new approach to 3-space launched by his mentor in Bonn, Julius Plucker. Just before Plucker died in 1868, he entrusted Klein to complete the classic monograph, Neue Geometrie des Raumes gegrundet auf die Betrachtung der geraden Linie als Raumelement. Overall responsibility for this project fell to Alfred Clebsch in Gottingen, which was how Klein first came to the prestigious Georgia Augusta. There he …
Reduction-oxidation dynamics of oxidized graphene: Functional group composition dependent path to reduction
2018
Micrometer-sized oxidation patterns containing varying composition of functional groups including epoxy, ether, hydroxyl, carbonyl, carboxyl, were created in chemical vapor deposition grown graphene through scanning probe lithography and pulsed laser two-photon oxidation. The oxidized graphene films were then reduced by a focused x-ray beam. Through in-situ x-ray photoelectron spectroscopy measurement, we found that the path to complete reduction depends critically on the total oxygen coverage and concentration of epoxy and ether groups. Over the threshold concentrations, a complex reduction-oxidation process involving conversion of functional groups of lower binding energy to higher bindin…
CCDC 973767: Experimental Crystal Structure Determination
2014
Related Article: Alexandre Abhervé, Juan Modesto Clemente-Juan, Miguel Clemente-León, Eugenio Coronado, Jaursup Boonmak, Sujittra Youngme|2014|New J.Chem.|38|2105|doi:10.1039/C3NJ01516E
A new simple chromo-fluorogenic probe for NO2 detection in air.
2015
[EN] A new chromo-fluorogenic probe, consisting of a biphenyl derivative containing both a silylbenzyl ether and a N,N-dimethylamino group, for NO2 detection in the gas phase has been developed. A clear colour change from colourless to yellow together with an emission quenching was observed when the probe reacted with NO2. A limit of detection to the naked eye of about 0.1 ppm was determined and the system was successfully applied to the detection of NO2 in realistic atmospheric conditions.
Die Cooligomerisierung von butadien mit α-hydroxycarbonsäureestern
1977
Abstract Glycolic acid butyl ester as well as lactic acid ethyl ester react with butadiene in the presence of palladium(II) acetylacetonate and triphenylphosphine as catalyst. The main product is the 2-trans, 7-octadienyl ether of the hydroxy acid ester, which is formed in yields from 65 to 80% at room temperature.
UraniumIV and uranyle salts, efficient and reusable catalysts for acylation of aromatic compounds
2000
Abstract Uranium tetrachloride, uranyle chloride, fluoride and also nitrate or acetate are very efficient homogeneous catalysts for the Friedel–Crafts acylation of aromatic compounds. With uranyle salts, the reaction, carried under dry air, is highly specific and the mono- or bisacylation products are obtained in high yield. Uranyle catalyst can be quantitatively recovered and reused and the organic products are obtained free of uranium.