Search results for "CAE"

The Crystal Structure of Rubidium and Cesium Hexachloro-, -bromo-, and -iodorhenates(IV)

1964

Preparation of dithiacycloalkynes by cyclization reactions applying the cesium effect

1993

Abstract The strained dithiacycloalkynes 3a,b and the larger heterocyclic alkynes 3c and 4 are obtained by cesium assisted cyclization reactions of the dithiols 1a–c and 1,4-dibromo-2-butyne (2). The reactivity of 3a–c was studied in cycloaddition and complexation reactions generating the adducts 5a,b and 6 and the silver and cobalt complexes 7 and 8.

Impedance spectroscopy characterization of functionalized alumina membranes

2005

Abstract Anodic alumina membranes have been impregnated with a protonic conductor either by immersion or by vacuum permeation of a saturated aqueous solution of CsHSO4 for different times. Synthetized salt, obtained through the reaction of cesium carbonate with sulphuric acid (in excess), contained a small quantity of Cs2SO4. Unmodified membranes consist of amorphous Al2O3 with a regular distribution of pores (average diameter: 200 nm) and are stable up to 850 °C. Long impregnation times caused partial dissolution of alumina, with formation of Al(HSO4)3 on the front surfaces as well as into pore walls. From the frequency dispersion of the impedance, the “macroscopic conductivity” of membran…

Stereoselektive synthese von D-α-hydroxycarbonsäuren bzw. D-α-hydroxycarbonsäuren enthaltenden depsipeptiden aus L-aminosäuren

1985

Abstract Depsipeptides containing D-α-hydroxy carboxylic acids are efficiently synthesized by the reactions of L-α-halo-carboxylic acid esters (obtained from L-amino acids) with caesium salts of N-protected amino acids.

Sediment delivery processes and the spatial distribution of caesium-137 in a small Sicilian basin

1998

The sediment delivery processes occurring in a small Sicilian basin are modelled using the spatially distributed SEDD model recently proposed by Ferro and Minacapilli. The model is applied by using soil data (grain-size distribution, organic matter content, etc.) of 129 samples uniformly distributed over the study area and compiling the available information (topographic map, soil data, etc.) into a Geographical Information System. Finally, the predictive capability of the distributed sediment delivery approach is tested experimentally using the caesium-137 measurement technique. The comparison between calculated sediment yield and the corresponding measured caesium-137 loss is used to vali…

A calixarene-based chromoionophore for the larger alkali metals

1995

Abstract A bis(arylazo)calix[5]arene crown ether derivative displays large spectral changes upon complexation of cesium and rubidium salts, with good selectivity over the smaller alkali metals.

Crown ethers derived from bicyclocalix[4]arenes as chromoionophores

2001

The synthesis of calix[4]arenes in which opposite phenolic units are connected by a poly(oxyethylene) bridge at the narrow rim and a 2,6-dimethylene-4-nitrophenol bridge at the wide rim is reported. For two derivatives with tetra- (4) and penta(oxyethylene) (5) bridges UV-Vis spectrophotometric studies were carried out in buffered solution in the presence of alkali metal ions. Their complexation was associated with changes in their UV-Vis spectra, especially with an increase of the absorption band at 450 nm. For 4 and 5 this was most intense in the presence of potassium and caesium ions, respectively, indicating that the calixarene with the shorter crown ether bridge is selective towards po…

Stereoselective Synthesis of β-1-O-Acyl Derivatives of Carbohydrates: An Application of the Cesium Effect.

1992

Abstract The stereoselective formation of anomerically pure 1-O-acyl derivatives of protected carbohydrates is achieved by reaction of the α-glycosyl halogenoses with cesium caboxylates.

Translational adaptation to heat stress is mediated by 5-methylcytosine RNA modification in Caenorhabditis elegans

2020

ABSTRACTMethylation of carbon-5 of cytosines (m5C) is a post-transcriptional nucleotide modification of RNA found in all kingdoms of life. While individual m5C-methyltransferases have been studied, the impact of the global cytosine-5 methylome on development, homeostasis and stress remains unknown. Here, usingCaenorhabditis elegans, we generated the first organism devoid of m5C in RNA, demonstrating that this modification is non-essential. We determined the localisation and enzymatic specificity of m5C sites in RNAin vivoand showed that animals devoid of m5C are sensitive to temperature stress. At the molecular level, we showed that loss of m5C specifically impacts decoding of leucine and p…

Il paradigma Marcello. Tra esilio e clementia Caesaris

2008

Nella pro Marcello Cicerone si propone di fare della sorte di Marcello, graziato da Cesare, il paradigma della restituzione alla res publica dei moderati boni viri che nel conflitto civile avevano aderito alla fazione pompeiana. Questa finalità viene perseguita occultando nella rappresentazione dell’esule il tratto distintivo dell’asprezza intransigente e presentando la scelta di Marcello, dello stesso Cicerone e dei loro amici di collocarsi sul fronte di Pompeo come un error humanus, giustificabile perché determinato da un fatum inesplicabile e non frutto di crudelitas o di cupiditas,: della correttezza di tale valutazione è trovata conferma proprio nella clementia elargita da Cesare agli …