Search results for "Tris"
showing 10 items of 2410 documents
Sterically geared tris-thioureas; transmembrane chloride transporters with unusual activity and accessibility
2015
Tris-N-arylthioureas derived in one step from 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene are remarkably effective anion carriers. With optimised aryl substituents their activities come close to the best currently known, suggesting that they might find use as readily available standards in anion transport research.
Ion-Pairing Effects in the Self-Assembly of a Fluorescent Pseudorotaxane
2006
Herein we report on the self-assembly, in a low polarity solvent, of a pseudorotaxane species comprising binaphthyl-26-crown-8 (BN26C8) as the macrocyclic host and anthracenyl-benzylammonium as the threadlike positively charged guest (ABH+). Absorption and luminescence data reveal a very efficient energy transfer process occurring from the binaphthyl to the anthracene singlet excited states. The self-assembly is highly dependent on the nature of the counteranion confirming the crucial role played by it in the competition between the self-assembly process and the formation of ion pairs (ABH+X-). This behavior can be readily evidenced in dilute solutions from the analysis of the luminescence …
Place and Positionality – Anthropo(topo)logical Thinking with Helmuth Plessner
2018
This paper explores a possible anthropological dimension of place by providing an interpretation of Helmuth Plessner’s philosophical approach which proposes to understand it as a twofold “implacement” of man – discussing both the place of man in the natural world and man’s specific relation to place that makes him take his place in the natural world. The interpretation follows Plessner’s idea of a natural set of stages, developed in his major work Die Stufen des Organischen und der Mensch, leading from inanimate objects to plants, animals, and humans. According to Plessner, each stage differs from the other by virtue of its respective spatial delineation toward, and its position in, the wor…
Comparative chemical composition, free radical-scavenging and cytotoxic properties of essential oils of six Stachys species from different regions of…
2009
Abstract The chemical composition of essential oils of six Stachys species, S. cretica L. ssp. vacillans Rech. fil., S. germanica L., S. hydrophila Boiss., S. nivea Labill., S. palustris L. and S. spinosa L., obtained by hydrodistillation, was studied by GC and GC–MS. All the oils have in common a great percentage of fatty acids and esters (24.2–58.5%) and a high amount of sesquiterpenes (16–35.9%), with the exception of the oil from S. palustris , which consisted mainly of carbonylic compounds (25.4%). The antioxidant activity by DPPH test and the antiproliferative activity on a series of human cancer cell lines (C32, amelanotic melanoma and ACHN, renal cell adenocarcinoma) were investigat…
Toxicological and bioactivity evaluation of blackcurrant press cake, sea buckthorn leaves and bark from Scots pine and Norway spruce extracts under a…
2021
Aqueous extracts from blackcurrant press cake (BC), Norway spruce bark (NS), Scots pine bark (SP), and sea buckthorn leaves (SB) were obtained using maceration and pressurized hot water and tested for their bioactivities. Maceration provided the extraction of higher dry matter contents, including total phenolics (TPC), anthocyanins, and condensed tannins, which also impacted higher antioxidant activity. NS and SB extracts presented the highest mean values of TPC and antioxidant activity. Individually, NS extract presented high contents of proanthocyanidins, resveratrol, and some phenolic acids. In contrast, SB contained a high concentration of ellagitannins, ellagic acid, and quercetin, exp…
La antropología como ciencia libidinosa. Diderot y el viaje de Bougainville
2005
Son innumerables los estudios que han abordado, desde temprano, la historia de la constitución de la antropología como disciplina empírica con vocación 'científica', como una de las ciencias humanas. Se muestra así una cierta obsesión por los orígenes, quizá síntoma de una frágil identidad. Uno de esos textos, de los más tempranos, The History of Anthropology} 1 fue escrito por Boas justo al principio del siglo pasado (1904) y tiene por objeto -fue una conferencia dada ante un publico académico variopintoreflexionar históricamente sobre una disciplina que todavía se debate para delimitar cuál es su objeto y método epistemológicos. Boas advierte desde el principio que no va a proceder dicien…
Lesings: mākslas principi un estētiskā audzināšana 18. gadsimta estētiskā racionālisma gaismā
2019
Darba mērķis ir apzināt Gotholda Efraima Lesinga estētiskās audzināšanas projektu apgaismības laikmeta estētiskā racionālisma kontekstā. Lai sasniegtu mērķi, ir izvirzīti trīs uzdevumi. Pirmkārt, sniegt ieskatu Lesinga priekšstatos par dažādu mākslas veidu uzdevumiem. Otrkārt, izprast Lesinga iezīmēto mākslas veidu sadarbību vai – tieši otrādi – to izslēdzošās attiecības. Treškārt, uzzināt, vai Lesinga gadījumā ir iespējams runāt par vienotu mākslas principu vai mākslas definīcijas izveidi. Darba gaitā secināts, ka vienotība nav iespējama mākslu hierarhiskā statusa un dažādo funkciju dēļ.
A study on the essential oil Ferulago campestris. How much does exstraction method influence the oil composition?
2010
The essential oil of different parts of Ferulago campestris (Bess.) collected in Sicily has been extracted by microwave-assisted hydrodistillation (MAHD) and by classic hydrodistillation (HD). A comparative qualitative- quantitative study on the composition of the oils was carried out. A total of 100 compounds were identified in the oils obtained by MAHD, whereas 88 compounds characterized the HD oils. The most prominent components were, in all different parts of F. campestris and in both extraction methods, 2,4,5- trimethylbenzaldehyde and 2,4,6-trimethylbenzaldehyde isomers; the latter was not previously found. The attempt to evaluate where the oil components are located in all parts of t…
Monoterpene derivatives from the flowers of Ferulago campestris, (Apiaceae).
2013
Ferulago campestris (Besser) Grec., (Ferula galbanifera (Mill) Kock. = F. campestris), finocchiazzo, is an annual or perennial herb of the Mediterranean area. In this paper the phytochemical studies of the CH2Cl2 and MeOH extracts of the flowers are described. Several ferulol derivatives and a new 10-hydroxy-verbenone ester (7) were isolated. The structure of the new compound was established by extensive NMR analysis, including HMBC and HSQC pulse sequences.