Search results for "49"
showing 10 items of 1208 documents
Ammonium formate-Pd/C as a new reducing system for 1,2,4-oxadiazoles. Synthesis of guanidine derivatives and reductive rearrangement to quinazolin-4-…
2021
1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH4CO2H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induce…
La censura nella Francia settecentesca e la figura del colporteur tra realtà e finzione
2015
La censura assume un’importanza fondamentale nella Francia settecentesca se si considera il vistoso aumento dei censori che passa da quarantuno all’inizio del secolo a settantotto alla vigilia della Rivoluzione. Cercando di raggirare i divieti imposti dalla censura, i colporteur ossia i venditori francesi ambulanti di libri eludano la sorveglianza nascondendo sotto il loro mantello sia scritti libertini che libelli politici, vale a dire i libri più amati e contestati dell’epoca, per poi venderli ai clienti piùabbienti. Censorship is of fundamental importance in eighteenth-century France, a fact corroborated by the increase in the number of censors throughout the century: from forty-one in t…
La correspondencia entre el P. Guzmán, Barbieru y Pedrell: revelaciones inéditas
2014
Vicente Lleó Balbastre y el género sicalíptico
2016
Oratio de oboedientia Friderici III coram Calixto III anno 1455 habita
Sense sign. - Data insegura, al voltant de 1480 L. gòt. - 33 lín. - Capll. grav. - Sense fol. - Filigr.: flor, monstre
Quantitative lower bounds to the Euclidean and the Gaussian Cheeger constants
2020
We provide a quantitative lower bound to the Cheeger constant of a set $\Omega$ in both the Euclidean and the Gaussian settings in terms of suitable asymmetry indexes. We provide examples which show that these quantitative estimates are sharp.
Folate deficiency as predisposing factor for childhood leukaemia: a review of the literature
2017
© The Author(s). 2017. Background: Folic acid and its derivates, known as folates, are chemoprotective micronutrients of great interest because of their essential role in the maintenance of health and genomic integrity. The supplementation of folic acid during pregnancy has long been known to reduce the risk of neural tube defects (NTDs) in the foetus. Folate metabolism can be altered by many factors, including adequate intake through diet. Folate deficiency can compromise the synthesis, repair and methylation of DNA, with deleterious consequences on genomic stability and gene expression. These processes are known to be altered in chronic diseases, including cancer and cardiovascular diseas…
Land Snail Fauna of “Porţile de Fier” (“Iron Gates”) Nature Park (Banat, Romania)
2014
Abstract The paper presents an analysis of terrestrial mollusc fauna of the “Iron Gates” Nature Park. Various types of habitats (e.g. forests, rocks, riparian areas) and substrates (e.g. limestone, conglomerate, crystalline schist) were analyzed. A total of 45 species of terrestrial gastropods were identified in 17 sampling points, four of which are mentioned for the first time in the area. Six other species cited in the literature were not found. Limestone substrate allows the development of large populations of terrestrial gastropods, but the specific diversity is larger when it is associated with a forest habitat. The current legal and illegal exploitation of limestone threatens the moll…
Benthic Macroinvertebrate Communities in the Northern Tributaries of the “Iron Gates” Gorge (Danube River)
2014
Abstract The paper presents the structure of the benthonic macro-invertebrates communities in the Berzasca, Sirinia, Liubcova, and Mraconia rivers. The results are based on quantitative benthos samples (95 samples), collected in July 2014 from 19 sampling stations within the study area. In longitudinal profile, the benthonic macro-invertebrate communities of the Sirinia, Liubcova and Berzasca rivers displays relatively large structural variability, while the communities of the Mraconia River displays smaller structural variability. The structure of the benthonic macro-invertebrate communities correlated with the biotope characteristics indicates the good ecological status of the analysed ri…
Suport System for the Management of the Sabanejewia aurata (De Filippi, 1863) Populations of the ROSCI0227 – Sighișoara-Târnava Mare
2016
Abstract ADONIS:CE was used to design a computer model for the management of Sabanejewia aurata (De Filippi, 1863) populations in the Natura 2000 site of Sighişoara-Târnava Mare (ROSCI0227). The recommended management model is based on the environmental needs of the species, inventoried according to the local habitats, as well as the indicators of conservation status and relevant management measures, and takes into account human pressures and threats identified in the research area. Such computer models were established for all protected fish species found at the site ROSCI0227.