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Rusu D.,University of Medicine and Pharmacy, Cluj-Napoca | Tomsa A.R.,Raluca Ripan Institute for Research in Chemistry | Turdean G.L.,Babes - Bolyai University | Cojocaru I.,University of Craiova | And 2 more authors.
Revue Roumaine de Chimie | Year: 2012

The new polyoxotungsto-bismutate, Na12[Cu3 2+(H2O)3(BiW9O33)2] ·47H2O (1), has been synthesized by reaction of Na9[BiW9O33] ·14H2O and Cu(CH3COO)2] ·H2O in NaAc/HAc buffer under moderate condition. This polyoxoanion was characterized by elemental and thermo-gravimetric analysis, FT-IR, Raman, UV, Vis, EPR spectroscopy, X-ray diffraction on single crystal and cyclic voltammetry. This allowed for the subsequent determination of the behavior of the encapsulated transition metal ions, their coordination by the tungstobismutate (III) fragments, the corresponding local symmetry and the type of metal-metal interactions. Compound 1 consists of two α-B-[BiW9O33]9- units, which are linked by an equatorial belt of three Cu(H2O)2+ cations. Three Na(H2O)2 + cations are also attached to the equatorial plane. The bond geometry is square-pyramidal against each Cu atom and trigonal-prismatic against each Na atom. Crystal data for 1 are: monoclinic, space group C2c, a=14.049(12) Å, b=23.360(19) Å, c=31.991(3) Å, α=90 o, β=99.217(2) o, γ=90 o, V=10364.2(15) Å3, Z=4.

Cosma S.C.,Technical University of Cluj Napoca | Balc N.,Technical University of Cluj Napoca | Leordean D.,Technical University of Cluj Napoca | Moldovan M.,Raluca Ripan Institute for Research in Chemistry | And 2 more authors.
Academic Journal of Manufacturing Engineering | Year: 2015

Selective laser melting (SLM) is widely gaining popularity as an alternative manufacturing technique for complex and customized implants. This technique has eliminated the constraints of shape and mechanical properties making it possible for fabrication of implants that are conform to the physico-mechanical requirements of implantation. The object of this article is to combine customized dental implants manufactured by SLM with bioactive surface treatments. After fabrication, the implants were coated in modified SBF solution with biodegradable β-TCP and Chitosan, respectively acid etching followed by grit-blasted with apatite. Mechanical studies were developed initially to determinate ultimate and yield tensile strength and Young modulus obtained with specific process parameters on standard samples. Finally, the implants were microscopically analyzed and measured the roughness. The purpose of this research was to improve the design and manufacturing process of novel customized parts for dentistry. © 2015 AJME.

Dadarlat D.,Romanian Institute of Isotopic And Molecular Technology | Streza M.,Romanian Institute of Isotopic And Molecular Technology | Onija O.,Romanian Institute of Isotopic And Molecular Technology | Prejmerean C.,Raluca Ripan Institute for Research in Chemistry | And 3 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

The paper is focused on the ability of using two complementary photothermal techniques for the measurement of all thermal parameters of some porous and/or semi-transparent solid samples whose composition, structure, and geometry do not allow a complete thermal characterization using a single technique. In this work, we combine a contact technique, photopyroelectric (PPE) calorimetry, with a non-contact one, infrared lock-in IR thermography (IRT), in order to investigate some solid samples such as dental composites, building materials, drugs, and semiconductors. The composition and the geometry of the investigated samples make the PPE method (in "front" detection configuration together with thermal-wave resonator cavity (TWRC) technique as scanning procedure) suitable for thermal effusivity measurements and IRT for thermal diffusivity investigations. In such a way, this combination of methods leads to a complete thermal characterization of the investigated materials. © 2014 Akadémiai Kiadó, Budapest, Hungary.

Pascalu V.,Technical University of Cluj Napoca | Soritau O.,Oncology Institute Prof Dr I Chiricuta | Popa F.,Technical University of Cluj Napoca | Pavel C.,Technical University of Cluj Napoca | And 6 more authors.
Journal of Biomaterials Applications | Year: 2016

The aim of the paper is to obtain and characterize k-carrageenan-chitosan dual hydrogel multilayers shell BSA gel microcapsules, as a carrier for curcumin, and as a possible antitumoral agent in biological studies. We used the CaCO3 template to synthesize non-toxic CaCO3/BSA particles as microtemplates by coprecipitating a CaCl2 solution that contains dissolved BSA, with an equimolar Na2CO3 solution. The microcapsules shell is assembled through a layer-by-layer deposition technique of calcium cross-linked k-carrageenan hydrogel alternating with polyelectrolite complex hydrogel formed via electrostatic interactions between k-carrageenan and chitosan. After the removal of CaCO3 through Ca2+ complexation with EDTA, and by a slightly treatment with HCl diluted solution, the BSA core is turned into a BSA gel through a thermal treatment. The BSA gel microcapsules were then loaded with curcumin, through a diffusion process from curcumin ethanolic solution. All the synthesized particles and microcapsules were stucturally characterized by: Fourier Transform Infrared Spectroscopy, UV-Vis Spectrometry, X-ray diffraction, thermal analysis, fluorescence spectroscopy, fluorescence optical microscopy, confocal laser scanning microscopy and scanning electron microscopy. The behavior of curcumin loaded microcapsules in media of different pH (SGF, SIF and PBS) was studied in order to reveal the kinetics and the release profile of curcumin. The in vitro evaluation of the antitumoral activity of encapsulated curcumin microcapsules on HeLa cell line and the primary culture of mesenchymal stem cells is the main reason of the microcapsules synthesis as BSA-based vehicle meant to enhance the biodisponibility of curcumin, whose anti-tumor, anti-oxidant and anti-inflammatory properties are well known. © SAGE Publications.

Streza M.,A-D Technologies | Dadarlat D.,A-D Technologies | Pop M.N.,A-D Technologies | Prejmerean C.,Raluca Ripan Institute for Research in Chemistry | And 4 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2010

Thermo-physical properties of some new dental restorative materials were investigated by means of photothermal radiometry (PTR) technique, in order to select the most suitable materials in terms of thermal biocompatibility. The measurement procedure is based on the analysis of the PTR signal (amplitude and phase) as a function of modulation frequency of radiation. The instrumental influence is eliminated by a normalization procedure obtained with a reference sample. The thermophysical parameters were obtained by using some multiparameter optimisation algorithms to fit the PTR experimental data.

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