Avadanei M.,Pponi Institute Of Macromolecular Chemical
Journal of Applied Polymer Science | Year: 2017
2,6-Di(4′-azidobenzylidene)-methylcyclohexanone (ABC) was one of the most used photoinitiators in negative photoresists industry, rendering insolubility of the resist films at short UV exposure times (several minutes). Although the photodecomposition of aromatic azides is very well established, the peculiarities of the irradiation medium impose specific reaction pathways for arylnitrenes. In this study, photoreactions of arylnitrenes resulted from ABC photolysis were applied in the photoinitiated crosslinking of 1,2-polybutadiene (1,2-PB), under soft monochromatic UV irradiation (365 nm). To elucidate the crosslinking mechanism, studies on a model compound were performed. 3-Methyl-1-butene was chosen to simulate the monomeric unit of 1,2-PB. As a support in photoproducts identifying and with the purpose of a deeper investigation of the ABC photochemistry alone, ABC was photolysed in a rigid matrix of poly(methyl methacrylate). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44694. © 2017 Wiley Periodicals, Inc.
Chiriac A.,Apollonia University |
Chiriac A.,Nicolina Medical Center |
Chiriac A.,Pponi Institute Of Macromolecular Chemical |
Brzezinski P.,th Military Support Unit |
And 2 more authors.
Clinical Interventions in Aging | Year: 2015
Green nails, also known as chloronychia or green nail syndrome, are characterized by green discoloration of the nail plate (greenish-yellow, greenish-brown, greenish-black), proximal chronic non-tender paronychia, and distolateral onycholysis. The cause is Pseudomonas aeruginosa infection of the nail plate in persons whose hands are constantly exposed to water, soaps, and detergents or are subject to mechanical trauma, especially in the elderly. Green or black coloration of the nails should raise suspicion for Pseudomonas infection and be treated with an oral quinolone (ciprofloxacin), particularly in aged patients. We present three cases of green nails in elderly persons. © 2015 Chiriac et al.
Lacramioara L.,Grtpopa University Of Medicine And Pharmacy |
Diaconu A.,Pponi Institute Of Macromolecular Chemical |
Butnaru M.,Grtpopa University Of Medicine And Pharmacy |
Verestiuc L.,Grtpopa University Of Medicine And Pharmacy
IFMBE Proceedings | Year: 2016
Antioxidant enzymes are involved in the therapy of the cardiovascular diseases associated with increased production of reactive oxygen species (ROS). The enzyme efficiency is dependent on the bioactive molecule’s ability to achieve therapeutically adequate levels at the target site. In this paper, superoxide dismutase (SOD) and catalase, enzymes involved in decomposition of reactive oxygen species, have been immobilized onto superparamagnetic iron oxide nanoparticles(SPIONs) and characterized. FT-IR data, particles mean diameter and zeta potential confirmed the enzymes immobilization onto SPIONs. The particles dimensions vary from 400nm for catalase immobilization to 1μm for SOD immobilization. The particles morphology was studied by scanning electron microscopy (SEM) and suggests the particles tendency for clustering during the drying process. The biofunctinalized SPIONs are degraded by esterases. The citocompatibility tests (MTT) indicated normal values for the cells viability in presence of SPIONs with immobilized enzymes. Enzymatic activity of magnetic particles has been determined indirect by NTBmethionine- riboflavin (in the case of superoxide dismutase) and direct, with H2O2 (for catalase). EnzySPIONs preserve an enzymatic activity which is dependent of the magnetic particles concentration, the enzyme nature and biological molecule conformation onto magnetic particle. © Springer Science+Business Media Singapore 2016.
Rusu M.,Al. I. Cuza University |
Airinei A.,Pponi Institute Of Macromolecular Chemical |
Rusu G.G.,Al. I. Cuza University |
Marin L.,Pponi Institute Of Macromolecular Chemical |
And 4 more authors.
Journal of Macromolecular Science, Part B: Physics | Year: 2011
Poly(azomethine sulfone)s were synthesized by reacting 4,4′-sulfonyl bis(4-chlorophenyl) with 2,2-bis(4-hydroxyphenyl)propane and azomethine bisphenol in different molar ratios. Thin films were deposited from solution onto glass substrates. Study of the temperature dependences of the electrical conductivity, , and Seebeck coefficient, S, were performed in the temperature range 300 K-500 K. Thermal activation energies of electrical conduction, Ea, calculated from these dependences, ranged between 1.50 eV and 1.85 eV. The values of Ea were smaller for polymers with extended conjugation systems. The possibility to use the polymers in thermistor technology is discussed. The aspect of the temperature dependences of and S shows that a model based on the energy band-gap representation can be successfully used for explaining the electronic transport mechanism in the higher temperature range. In the lower temperature range, the mechanism of the electrical conduction is discussed in terms of the Mott variable range hopping conduction. The values of some optical parameters (absorption coefficient, optical band gap, etc.) were determined from transmission spectra. Copyright © Taylor & Francis Group, LLC.
Avadanei M.,Pponi Institute Of Macromolecular Chemical |
Cozan V.,Pponi Institute Of Macromolecular Chemical |
Shova S.,Pponi Institute Of Macromolecular Chemical |
Paixao J.A.,University of Coimbra
Chemical Physics | Year: 2014
The crystalline structure and optical properties of N-salicylidene-p-cyanoaniline and N-salicylidene-p-carboxyaniline were investigated in solid state (microcrystalline powder), with the purpose to connect the effects of substitution and crystal packing with their optical properties. Diffuse reflectance and fluorescence spectroscopy were used to study the absorption and emission properties upon photoirradiation and cooling down to the liquid nitrogen temperature. The Stokes-shifted fluorescence, with a quantum yield of about 10-2-10-1, is given by the tautomeric cis-keto species formed as a result of the excited state intramolecular proton transfer from the initial enol structure. Despite their similar geometrical parameters, only SA-COOH is photochromic, which is in contradiction with literature. On the other side, the thermochromism is especially strong at SA-CN. The study shows the behavior of SA-CN similar to that of a classical anil, while SA-COOH presents interesting features that contradict the presumed behavior based only on its supramolecular structure. © 2014 Elsevier B.V. All rights reserved.
Munteanu B.S.,Universitatea Al za Iasi |
Munteanu B.S.,University of Genoa |
Brebu M.,Pponi Institute Of Macromolecular Chemical |
Vasile C.,Pponi Institute Of Macromolecular Chemical
Polymer Degradation and Stability | Year: 2013
Three types of acrylonitrile copolymers (acrylonitrile-styrene-butadiene copolymer (ABS1), acrylonitrile-styrene random copolymer (SAN 2) and acrylonitrile-butadiene random copolymer (BAN3) were studied by thermogravimetry (TG/DTG4) and by pyrolysis in a semi-batch process at 450 C in order to find structure-thermal behaviour relationships. The overlapped thermo-oxidative degradation processes were separated and the corresponding kinetic parameters were calculated. The TG/DTG studies have evidenced that the styrene-acrylonitrile interactions stabilize the nitrile groups reacting by chain scission rather than cyclization and destabilize the styrene units. Also, the cyclization of the acrylonitrile units in ABS is favoured by interactions with the styrene and butadiene units. The pyrolysis behaviour evidenced that the styrene-acrylonitrile interactions in SAN and ABS lead to the formation of 4-phenylbutyronitrile as the most important decomposition compound. ABS shows similar composition of the degradation oil with SAN copolymer therefore in the ABS the styrene-butadiene interactions are less important than those between styrene and acrylonitrile units. © 2013 Elsevier Ltd. All rights reserved.