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91.
92.
Adriana Popa Simona Gabriela Muntean Oana Maria Paska Smaranda Iliescu Gheorghe Ilia Zhengpu Zhang 《Polymer Bulletin》2011,66(3):419-432
The synthesis of styrene–divinylbenzene copolymers functionalized with α-hydroxyphosphonic acid groups is presented. The phosphorus content was determined in order to calculate the degree of functionalization with pendant α-hydroxyphosphonic group, with values of 0.66 for St–1%DVBHOPHOS and 3.14 for St–6.7%DVBHOPHOS. Their characterization by IR, thermogravimetry is reported. The kinetics of adsorption of three dyes on St–6.7%DVBHOPHOS polymer was studied. 相似文献
93.
Petru Pascuta Adrian Vladescu Gheorghe Borodi Eugen Culea Romulus Tetean 《Journal of Materials Science: Materials in Electronics》2012,23(2):582-588
Two different glass ceramics with the composition of the (Fe2O3)x·(B2O3)(60−x)·(ZnO)40, where x = 12.5 and 15 mol%, have been synthesized using the melt-quench method. The X-ray diffraction (XRD) patterns show the presence
of nanometric zinc ferrite (ZnFe2O4) crystals, with spinel structure, in a glassy matrix after cooling from melting temperature. The estimated amount of crystallized
zinc ferrite varies between 16 and 35%, as a function of the chemical composition. Glass transition (Tg), crystallization (Tp) and melting (Tm) temperatures were determined by differential thermal analysis (DTA) investigations. Fourier transform infrared (FTIR) data
revealed that the BO3 and BO4 are the main structural units of these glass ceramics network. FTIR spectra of these samples show features at characteristic
vibration frequencies of ZnFe2O4. Electron paramagnetic resonance (EPR) measurements show the presence of isolated Fe3+ ions predominantly situated in rhombic vicinities and as well as the Fe3+ species interacting by dipole–dipole interaction or to their superexchange coupled pairs in clustered formations. The magnetic
properties of the studied glass ceramics were investigated by vibrating sample magnetometer (VSM). From the magnetization
curves for glass ceramic containing 15 mol% Fe2O3 it was found that the nanoparticles exhibit ferromagnetic interactions combined with superparamagnetism with a blocking temperature,
TB. For studied samples the hysteresis is present. The coercive field is dependent on composition and magnetic field being around
0.05 μB/f.u for measurements performed in maximum 0.4 T. 相似文献
94.
Gabriel Biener Michael R. Stoneman Gheorghe Acbas Jessica D. Holz Marianna Orlova Liudmila Komarova Sergei Kuchin Valeric? Raicu 《International journal of molecular sciences》2014,15(1):261-276
Multiphoton micro-spectroscopy, employing diffraction optics and electron-multiplying CCD (EMCCD) cameras, is a suitable method for determining protein complex stoichiometry, quaternary structure, and spatial distribution in living cells using Förster resonance energy transfer (FRET) imaging. The method provides highly resolved spectra of molecules or molecular complexes at each image pixel, and it does so on a timescale shorter than that of molecular diffusion, which scrambles the spectral information. Acquisition of an entire spectrally resolved image, however, is slower than that of broad-bandwidth microscopes because it takes longer times to collect the same number of photons at each emission wavelength as in a broad bandwidth. Here, we demonstrate an optical micro-spectroscopic scheme that employs a laser beam shaped into a line to excite in parallel multiple sample voxels. The method presents dramatically increased sensitivity and/or acquisition speed and, at the same time, has excellent spatial and spectral resolution, similar to point-scan configurations. When applied to FRET imaging using an oligomeric FRET construct expressed in living cells and consisting of a FRET acceptor linked to three donors, the technique based on line-shaped excitation provides higher accuracy compared to the point-scan approach, and it reduces artifacts caused by photobleaching and other undesired photophysical effects. 相似文献
95.
Gheorghe Maria Daniela BergerSilviu Nastase Ionela Luta 《Microporous and mesoporous materials》2012,149(1):25-35
Building a detailed kinetic model for the drug release from an ordered mesoporous support is a difficult task due to various physico-chemical processes involved, including complex adsorption-desorption and diffusion steps. A compartmented mechanistic model for the drug release from a silica mesoporous (functionalized) support is elaborated to correlate the experimental drug release data under various release conditions. The identified model parameters are interpreted in relationship to the delivery system characteristics (drug, support, and linker properties) to be used for designing a system with a controlled release. Extended model predictions are compared with those of various semi-empirical or overall diffusion models in terms of quality (adequacy, validity, reliability) and parameter significance to determine the information loss when simplified models are used for design purposes. Exemplification is made for the release of irinotecan from a MCM-41 support unfunctionalized vs. functionalized with 3-aminopropyl triethoxysilane or triethoxyvinylsilane in a synthetic intestinal fluid. 相似文献
96.
Several α-(1H-imidazol-1-yl)-ω-phenylalkanes were synthesized and evaluated as novel inhibitors of heme oxygenase (HO). These compounds were found to be potent and selective for the stress-induced isozyme HO-1, showing mostly weak activity toward the constitutive isozyme HO-2. The introduction of an oxygen atom in the alkyl linker produced analogues with decreased potency toward HO-1, whereas the presence of a sulfur atom in the linker gave rise to analogues with greater potency toward HO-1 than the carbon-containing analogues. The most potent compounds studied contained a five-atom linker between the imidazolyl and phenyl moieties, whereas the most HO-1-selective compounds contained a four-atom linker between these groups. The compounds with a five-atom linker containing a heteroatom (O or S) were found to be the most potent inhibitors of HO-2; 1-(N-benzylamino)-3-(1H-imidazol-1-yl)propane dihydrochloride, with a nitrogen atom in the linker, was found to be inactive. 相似文献
97.
98.
Florina Branzoi Zoia Pahom Gheorghe Nechifor 《Journal of Adhesion Science and Technology》2018,32(21):2364-2380
In this paper, electropolymerization technique has been used for the obtained of new composite: polypyrrole – dioctyl sulfosuccinate sodium/poly N-ethylaniline (PPY-AOT/PNEA) coatings over carbon steel of type OLC 45 electrode for anticorrosion protection. The PPY-AOT/PNEA coatings were successfully synthesized onto OLC 45 electrode by galvanostatic deposition from aqueous solutions 0.1 M NEA, 0.1 M PY, 0.01 M AOT and 0.3 M H2C2O4 solution at different current densities (5, 3 and 1 mA/cm2) in different molar ratio. The anionic surfactant (AOT) as a dopant ion used during electropolymerization can have a significant result on the anticorrosion protection of the composite film by hindering the penetration of aggressive ions. The polymeric composite coatings have been analyzed by cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) methods. The corrosion resistance of PPY-AOT/PNEA coated carbon steel has been examined by potentiodynamic polarization techniques and electrochemical impedance spectroscopy (EIS) methods in 0.5 M H2SO4 solutions. The data of the corrosion samples demonstrated that PPY-AOT/PNEA coatings assure a great anticorrosion protection of OLC 45 electrode in corrosive media. The corrosion rate of PPY-AOT/PNEA coated OLC 45 has been indicated to be ~9 times lower than of uncoated electrode. The corrosion protection effectiveness of the composite coating is more than 89%. The best efficiency is accomplished of PPY-AOT/PNEA obtained by electrodeposition at 5 mA/cm2 current densities applied in molar ratio 5:1. 相似文献
99.
Violeta Paşcalău Emoke Pall Mihaela Tertis Maria Suciu Cecilia Cristea Gheorghe Borodi 《国际聚合物材料杂志》2019,68(1-3):60-72
AbstractThe aim of this study is to develop core shell microcapsules of bovine serum albumin (BSA) gel with a complex polyelectrolite multilayer shell of natural polysaccharides with opposite charges, pectin (P), chitosan (Chi), and hyaluronic acid (HA) respectively, encapsulating Doxorubicin (Dox) as a carrier for targeted anti-tumoral treatment of hepatic cell carcinoma (HCC). A sacrificial CaCO3 template method was used in order to obtain microcapsules with a BSA gel core and a layer-by-layer (Lbl) deposition technique of polyelectrolite complexes formed between P/Chi in the inner layers and HA/Chi in the outer shell layers. The preformed microcapsules, BSA gel/P/Chi/HA, noted as ms, have been applied for Dox encapsulation (ms-Dox). Dox encapsulation and release in different pH media were studied in order to elucidate the interactions between pH dependently charged species involved in the Dox loading/releasing processes. The structure characterization of ms/ms-Dox was evaluated by FTIR and UV-Vis spectroscopy, X-ray diffraction, thermal analy sis, optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. The in vitro study for citotoxicity assessment on normal and tumoral cells of both ms and ms-Dox was performed using mesenchymal stem cells (MSCs) and Hep2G HCC cell lines. Results of physical-chemical analyses confirm the successful encapsulation of Dox in ms, and the in vitro biological study recommends ms-Dox as a candidate for future in vivo research as a targeted anti-tumoral treatment modality applications. 相似文献
100.
Thomas Dippong Oana Cadar Erika Andrea Levei Iosif-Grigore Deac Gheorghe Borodi 《Ceramics International》2018,44(9):10478-10485
The paper presents the influence of diol (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol and 1,4-butanediol) on the formation of magnetic crystalline cobalt ferrite embedded in polyvinyl alcohol-silica hybrid matrix at 200?°C. Formation of crystalline oxides (CoFe2O4, Co3O4 and Co2SiO4) was studied by X-ray diffraction and Fourier transformed infrared spectroscopy. The effect of annealing temperature and diol chain length on the cobalt ferrite nanocrystallites size was investigated. Using transmission electron microscopy, the size and shape of particles obtained at 200?°C were recorded and compared to those obtained by annealing at 500, 800 and 1100?°C. The saturation magnetization (Ms) and coercive field were calculated from the magnetic hysteresis loops of nanocomposites. The Ms was influenced by the particle size and crystallinity only for nanocomposites annealed at 800 and 1100?°C, when the magnetic domains started to form and to be larger than the critical particle size. The diols used in the synthesis influence both the oxidic phase formation and its properties. 相似文献