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Neda I.,Institutul National Of Cercetare | Fodor E.,TU Braunschweig | Maftei C.V.,TU Braunschweig | Mihorianu M.,TU Braunschweig | And 2 more authors.
European Journal of Organic Chemistry | Year: 2013

This paper reports the synthesis of the new enantiopure amino aldehydes, 9-aminoquincorine-10-aldehyde (1) and 9-aminoquincoridine-10-aldehyde (2). These alkaloid-like compounds are derivatives of the Cinchona alkaloids quinine and quinidine. Their application as chiral building blocks in the synthesis of novel compounds is demonstrated by the reduction and reductive amidation of the aldehyde moiety. Furthermore, their use in early drug discovery and supramolecular chemistry is described. The synthesis and selected reactions for two new quincorine/quincoridine (QCI/QCD) motifs, N-protected 9-aminoquincorine-10-aldehyde and N-protected 9-aminoquincoridine-10-aldehyde, are presented. As unprecedented motifs with an alkaloid-like nature, they are of interest for the pharmaceutical industry. Reduction of these aldehydes gave C-10 alcohols, which can be used in supramolecular chemistry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Lungu A.,Institutul National Of Cercetare | Sarbu A.,Institutul National Of Cercetare | Fruth V.,Institutul Of Chimie Fizica A Academiei Romane Of Stiinte | Constantin F.,Polytechnic University of Bucharest | And 2 more authors.
Revista Romana de Materiale/ Romanian Journal of Materials | Year: 2012

A series of new inorganic/organic composites were synthesized by polymerization of acrylic acid in a concentrated aqueous suspension of alumina powder, using N,N'-methylenebisacrylamide as crosslinker. The inorganic/organic composites were characterized by scanning electron microscopy (SEM), thermal analysis (TGA/DTG), infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Composite materials, with a volumetric shrinkage ranging from 50 to 87% depending on the acrylic acid concentration, were obtained. By increasing the acrylic acid concentration, the compressive strength increased up to 230 MPa. It was demonstrated that these composite systems can form porous alumina ceramic materials with ~80% porosity after burning off the organic network. Source


Velciu G.,Institutul National Of Cercetare | Velciu G.,Polytechnic University of Bucharest | Melinescu A.,Polytechnic University of Bucharest | Marinescu V.,Institutul National Of Cercetare | And 3 more authors.
Revista Romana de Materiale/ Romanian Journal of Materials | Year: 2014

Four compositions in the range of 85-90 % CeO2, the other being SrO, CaO or Y2O3combined two or three were studied. The mixtures have been homogenized by a wet route for 10 hours. After drying the obtained powders were subjected to thermal analysis which showed that in the process of grinding chemical changes occur. The apparent and relative densities were measured on the samples sintered at temperatures of 1350 and 1400°C resulting that the relative densities of the samples are between 79 and 92%. X-ray diffraction revealed that the main mineralogical compound of the samples, thermally treated in the range of 1300-1400°C, is a solid solution with a structure of fluorite type specific to CeO2. For some samples were also identified CaY4O7and SrCeO3, compounds resulting by solid-phase reactions and two solid solutions of the type SrCe0,85Y0,15O2,95and (Ce,Y)2O3.The microstructure of the studied samples was investigated by electron microscopy and the results showed that the samples exhibit rounded and needle-shaped grains of different sizes. Electrical measurements have shown that three of samples have a corresponding behavior to solid electrolytes usable for ITSOFC cells. Source


Bratu M.,Institutul National Of Cercetare | Dumitrescu O.,Polytechnic University of Bucharest | Vasile O.,Polytechnic University of Bucharest | Constantin A.C.,Institutul National Of Cercetare | And 2 more authors.
Revista Romana de Materiale/ Romanian Journal of Materials | Year: 2014

Noise is a 'non-periodic sounds' complex which affects biological and psychological state of people and other natural organisms. The present paper is dedicated to some new polymeric composites with sound-absorbing properties. The originality consists in obtaining new polymeric composites from formaldehyde resin and various waste types used as reinforcing agents. The soundabsorbing capacity of the new composites varies depending on the proportion of waste used. The absorbing coefficient is presented for each sample; it depends on the porosity of the composite material obtained at the interface between the matrix and reinforcing agent. Source


Tardei C.,ICPE CA | Mitrea S.,ICPE CA | Craciunescu O.,Institutul National Of Cercetare | Oprita E.I.,Institutul National Of Cercetare | Trusca R.,SC.METAV S.A
Revista Romana de Materiale/ Romanian Journal of Materials | Year: 2012

Intensive research is conducted both in understanding the phenomenon of "repair/healing of the bone" and for the development of techniques, devices and materials for effective applications involved in bone regeneration. This study is aimed at the development of a method to fabricate porous spherical tri-calcium phosphate (β-TCP) granules, which can be impregnated with a drug. Microspheres were prepared by the ionotropic gelation technique using CaCl2 as cross-linking agent. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM). In vitro cell culture tests showed that both ceramic microsphere types were highly biocompatible and favored cell growth during 72 hours of cultivation. Porous tri-calcium phosphate microspheres can be used for bone void filler, but also for drug delivery systems. Source

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