Search results for "Urea"
showing 10 items of 888 documents
Sesquiterpene lactones, lignans and aromatic esters from Cheirolophus species
1994
Abstract The aerial parts of five Cheirolophus species yielded three new guaianolides, a new lignan and three new aromatic esters, together with other known compounds of the same type.
San Pedro, como era calvo / Saint Peter, as He Was Bald
2018
Resumen. La calvicie de san Pedro que encontramos diversamente reflejada en la tradición popular católica podría muy bien deberse a un episodio referido en la Legenda Aurea (siglo xiii): cuando el apóstol predicaba en Antioquía, sus habitantes, haciendo burla de sus enseñanzas cristianas, le rasuraron la coronilla. Abstract. The fact that Saint Peter is depicted as bald in the Catholic popular tradition is probably due to an episode narrated in the Legenda Aurea (XIIIth century): when St. Peter preached in Antioch, the inhabitants shaved the top of his head in an attempt to mock the Christian law.
Perceived Competence in the Face of Death before and after Nursing Studies: An Intrasubject Longitudinal Study
2021
Perceived competence is a subject’s perception of being able to interact effectively with the environment. Perceived Competence in the face of death in Nursing degree programs in which the presence of the subject of death and bereavement is key becomes more topical and relevant. The objective of this study is to determine whether this competence is improved through Nursing Studies. This study was designed as paired repeated intrasubject measures, initial measurement at the beginning of the first year and second measurement in the fourth year of the Nursing degree. One hundred and seventeen nursing students were assessed. Significant improvement is evidenced in three of the four dimensions o…
Didactics of mathematics and architecture: the golden ratio in la Lonja de Valencia
2016
[EN] This paper has a twofold purpose. First, to structure and relate a teaching experience on the tutoring of a graduation work in Mathematics made in the University of Valencia. The main property of the didactic purpose involved in the project is that it deals with the geometric properties of a landmark building of the city of Valencia. Our aim is to analyze the process of formulation, firming up, documentation and elaboration of the work that was followed during this experience. Second, to analyze the methodology used to obtain and valuate the results that come from one of the fundamental parts of this work: the harmonic decomposition of the building named Lonja de la Seda in Valencia
A View from the Garden: Contemplative Isolation and Constructive Sociability in Lucretius and in the Epicurean Tradition
2021
It is often assumed that Epicurean philosophy and its foremost Roman prophet, T. Lucretius Carus, adopted a deeply hostile attitude towards both politics and religion. Individualistic (or even solipsistic) interpretations of Epicureanism – as well as of the Epicurean catechism of De Rerum Natura – have long co-existed with, and provided support to, the claim that the Epicureans attached little value to religious experiences. In the present paper, I shall argue that, in this and many other respects, the modern reception of Epicureanism – with its brave aspirations after the liberation of science from social and religious restraints – has had undue influence on our understanding of De Rerum N…
Dimerization of the kinase ARAF promotes MAPK pathway activation and cell migration.
2014
The RAF family of kinases mediates RAS signaling, and RAF inhibitors can be effective for treating tumors with BRAF V600E mutant protein. However, RAF inhibitors paradoxically accelerate metastasis in RAS -mutant tumors and become ineffective in BRAF V600E tumors because of reactivation of downstream mitogen-activated protein kinase (MAPK) signaling. We found that the RAF isoform ARAF has an obligatory role in promoting MAPK activity and cell migration in a cell type–dependent manner. Knocking down ARAF prevented the activation of MAPK kinase 1 (MEK1) and extracellular signal–regulated kinase 1 and 2 (ERK1/2) and decreased the number of protrusions from tumor cell spheroids in three-dimensi…
Sesquiterpenoids in subtribe Centaureinae (Cass.) Dumort (tribe Cardueae, Asteraceae): distribution, (13)C NMR spectral data and biological propertie…
2012
Asteraceae Bercht. & J. Presl is one of the biggest and most economically important plant families. The taxonomy and phylogeny of Asteraceae is rather complex and according to the latest and most reliable taxonomic classification of Panero & Funk, based on the analysis of nine chloroplast regions, the family is divided into 12 subfamilies and 35 tribes. One of the largest tribes of Asteraceae is Cardueae Cass. with four subtribes (Carlininae, Echinopinae, Carduinae and Centaureinae) and more than 2500 species. Susanna & Garcia-Jacas have organized the genera of Centaureinae (about 800 species) into seven informal groups, which recent molecular studies have confirmed: 1. Basal genera; 2. Vol…
Solid-state NMR and computational studies of tetratolyl urea calix[4]arene inclusion compounds.
2009
Solid-state guest dynamics of tetratolyl tetraurea calix[4]arene tetrapentylether dimeric capsules filled with different types of aromatic guests such as benzene-d6, fluorobenzene-d5 and 1,4-difluorobenzene were studied. Upon inclusion, all guest moieties revealed complexation-induced shifts varying from 2.8 ppm to 5.1 ppm. All guest molecules were shown to undergo distinct motions, ranging from mere C6-rotations of benzene-d6 to (ill-defined) 180 degrees phenyl flips of fluorobenzene-d5. In all cases, dynamic heterogeneities were identified based on 2H lineshape deconvolution. In addition, by combination of both a computed nucleus independent chemical shift (NICS) map and explicit 19F and …
Preferred dimerization of tetra-tolyl- and tetra-tosylurea derivatives of flexible and rigidified calix[4]arenes
2004
The dimerization of tetratolyl- and tetratosyl-urea derivatives 1 and 2, derived from a tetrapentoxy calix[4]arene in the cone conformation and of the corresponding tetra-urea derivatives 3 and 4, in which the cone conformation is rigidified by the two crown-3 tethers, have been studied. All six possible equimolar mixtures were examined by 1H NMR using CDCl3 and CD2Cl2 as solvents. While no heterodimers are found for the combinations 1/3 and 2/4 in either solvent, all remaining combinations lead to the (exclusive) formation of heterodimers in CD2Cl2. In CDCl3 heterodimers are only observed for the combinations of 3 with 2 or 4. These results are discussed in terms of entropic and enthalpic …
Guest exchange in dimeric capsules formed by tetra-urea calix[4]arenes
2008
Ten tetra-urea calix[4]arene derivatives with different ether residues (methyl, pentyl, benzyl, all combinations of methyl and pentyl, 1,3-dibenzyl-2,4-dipentyl), including also the tetrahydroxy compound and the 1,3-dipentyl ether, were synthesised. Their urea groups were substituted with a lipophilic residue to ensure sufficient solubility in cyclohexane. Thus, kinetics for the exchange of the included guest (benzene) against the solvent (cyclohexane) could be followed by 1H NMR spectroscopy. The apparent first order rate constants decrease with increasing size of the ether residues from methyl to benzyl by more than three orders of magnitude. This can be understood by a decreasing flexibi…