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681.
Alina Tirsoaga Diana Visinescu Bogdan Jurca Adelina Ianculescu Oana Carp 《Journal of nanoparticle research》2011,13(12):6397-6408
Nanosized metal aluminates, MAl2O4 (M = Ni, Co), have been prepared following a nonpolluting, low temperature, and self-sustaining starch single-fuel combustion
synthesis. The mixed fuel-coordinating actions of starch have given rise to an intermediary precursor which afforded monodisperse
metal aluminate nanoparticles. The thermal analysis of the [M(II), Al(III)]-starch precursors indicates a similar thermochemical
reactivity for the two compounds, displaying a sequence of well-defined decomposition stages associated with three endothermic
effects and three/four (nickel/cobalt) exothermic ones. The XRD data confirm the formation of spinelic phase and a continuous
growth of particle sizes with the increase of calcination temperatures. The mechanisms proposed for the formation of metal
aluminates essentially consist in a combination of solid-state reactions of amorphous NiO/Co3O4 and Al2O3 simple oxides. The evaluation criterion of Ni(II) cations into the spinelic lattice is original and is based on the distinct
occupancy degree of tetrahedral and octahedral sites in NiAl2O4 and γ-Al2O3. TEM/HRTEM investigations performed on the cobalt(II) and nickel(II) aluminate oxide powders resulted after calcination at
800 and 900 °C, respectively, for 1 h show the formation of irregular and isolated plate-like particles for Co(II)-based spinelic
oxides (the average particle size is 16.6 nm) and submicron aggregates of small, bimodal, and almost uniform (as shape and
size) of NiAl2O4 mixed oxide (the mean particle size is 33.6 nm). The NIR–UV–Vis spectra for the resulted MAl2O4 (M = Co, Ni) mixed oxides reveal a massive presence of tetrahedral divalent cations both for short- and long-time calcined
samples. NiO impurities are detected using FTIR and electronic spectra for all NiAl2O4 samples. 相似文献
682.
Raymond L. D. Whitby Alina Korobeinyk Sergey V. Mikhalovsky Takahiro Fukuda Toru Maekawa 《Journal of nanoparticle research》2011,13(10):4829-4837
Single-layer graphene oxide (SLGO) possesses carboxylic and hydroxyl groups suitable for reactions with aliphatic or aromatic
diisocyanate molecules. TEM analysis reveals that aliphatic diisocyanate molecules caused SLGO to scroll into star-like formations,
whereas aromatic diisocyanate molecules retained SGLO in a flat-sheet morphology. TGA confirms the stabilisation of the formed
urea and urethane groups on SLGO, but the onset of sheet pyrolysis occurs at a lower temperature due to isocyanate reactions
with anhydride and epoxide groups embedded in the sheet. Pendant isocyanate groups act as bridging units to facilitate the
attachment of pyrrole molecules, which are then used as anchor sites for the covalent polymerisation of pyrrole to polypyrrole
(PPy). The use of FeCl3 as the polymerisation catalyst generated both covalent and free PPy, but also iron hydroxide nanoparticles were observed
decorating the SLGO surface. When using ammonium persulfate as a catalyst and dodecylbenzenesulfonate as a dopant, free PPy
could be removed under treatment with solvents to leave a purely covalent system. Discrete regions of SLGO were observed decorated
with nanoparticles of PPy along the edge or across the surface of individual sheets. It was found that the flexibility of
the SLGO sheet and the type of diisocyanate used directly affected the electrical resistance of the final composite. 相似文献
683.
The fast neutron therapy facility at the University of Washington has been in routine clinical use for 25 years. 50.5 MeV protons produce neutrons in a beryllium target mounted on an isocentric gantry. Beam shaping is accomplished with a 40-leaf collimator. Dosimetry measurements for treatment planning and calibration are performed with tissue equivalent ion chambers. A layered phantom of alternating Solid Water® and Plastic Water® slabs has been developed for rapid dose verification measurements. The neutron field in the room has been used for radiation testing of electronic components. 相似文献
684.
Mihaela Homocianu Alina M. Ipate Corneliu Hamciuc Anton Airinei 《Journal of fluorescence》2018,28(5):1217-1224
The photophysical properties of the three 1,3,4-oxadiazole derivatives containing fluorene (Ox-FL); fluorene and phenolphtaleine (Ox-FL-FF); or fluorene and bisphenol A (Ox-FL-BPA) moieties in the main chain were investigated by the fluorescence and absorption spectroscopy in different solvents and in the solid state. The electronic absorption spectra included a strong absorption band located in the 270–395 nm region, with a maxima around at 302 nm. The fluorescence excitation spectra were also characterized by one broad band, appearing in the wavelength range of 220–340 nm. All samples displayed the emission bands around 356–373 nm and exhibit high quantum yields ranged from 31.61 to 90.77%, in chloroform solution. The sensitivity of the emission spectra on medium characteristics (polarity, acidity and basicity) were evaluated by using the Catalan solvent scale and the fluorescence titration with a dilute acid solution. 相似文献
685.
The prevalence of cephalosporine-resistant (3GC-R) strains among United States community-related research samples ranged from 5.6 to 10.8%, while, in the European countries, it was 1.2% to 10.1%. Several studies suggest that meat of animal origin could be one of the reservoirs of 3GC-R bacteria. Here, 86 raw meat samples (turkey, pork, chicken and beef) were collected randomly and verified for the presence of 3GC-R bacteria. The 3GC-R bacteria were isolated, identified and characterized phenotypically (antibiotic resistance, motility and biofilm) and genotypically (repetitive-sequence-based rep-PCR) to elucidate any correlations with principal component analysis (PCA). From 28 3GC-R positive samples, 41 strains were isolated, from which the majority belonged to Serratia fonticola (39%), followed by Escherichia coli (19.5%), Enterobacter cloacae (17.1%) and Klebsiella pneumoniae (14.6%). The isolates of E. coli and S. fonticola presented diverse profiles in rep-PCR. Generally, 3GC-R strains were more resistant to antibiotics used in veterinary medicine than in human medicine. PCA derived from antibiotic resistance, motility and biofilm formation of S. fonticola and E. coli strains showed that resistance to beta-lactams was separated from the resistance to other antibiotic classes. Moreover, for the S. fonticola, E. coli and En. cloacae, the type of meat can create a specific tendency towards antibiotic resistance and phenotypic characteristics for S. fonticola, while these relationships were not found for other tested species. 相似文献
686.
Alina Climova Ekaterina Pivovarova Bartomiej Rogalewicz Anita Raducka Magorzata Szczesio Izabela Korona-Gowniak Agnieszka Korga-Plewko Magdalena Iwan Katarzyna Gobis Agnieszka Czylkowska 《Molecules (Basel, Switzerland)》2022,27(11)
New coordination compounds of Mn(II), Fe(III), Co(II), and Ni(II) and the biologically active ligand L (N′-benzylidenepyrazine-2-carbohydrazonamide) were synthesized and characterized by appropriate analytical techniques: elemental analysis (EA), thermogravimetric analysis (TG–DTG), infrared spectroscopy (FTIR), and flame-atomic absorption spectrometry (F-AAS). The biological activity of the obtained compounds was then comprehensively investigated. Rational use of these compounds as potential drugs was proven by ADME analysis. All obtained compounds were screened in vitro for antibacterial, antifungal, and anticancer activities. Some of the studied complexes exhibited significantly higher activity than the ligand alone. 相似文献
687.
Anca Suteanu-Simulescu Mirela Sarbu Raluca Ica Ligia Petrica Alina Diana Zamfir 《Electrophoresis》2023,44(5-6):501-520
The expression of gangliosides in central nervous system is a few times higher than in the extraneural tissue, a characteristic highlighting their major role at this level. Although in very low amounts, gangliosides are ubiquitously distributed in body fluids too, where, depending on many factors, including pathological states, their composition fluctuates, thus having diagnostic value. Ganglioside investigation in biological fluids, which, except for cerebrospinal fluid (CSF), may be sampled noninvasively, was for years impeded by the limited sensitivity of the analytical instrumentation available in glycomics. However, because the last decade has witnessed significant developments in biological mass spectrometry (MS) and the hyphenated separation techniques, marked by a major increase in sensitivity, reproducibility, and data reliability, ganglioside research started to be focused on biofluid analysis by separation techniques coupled to MS. In this context, our review presents the achievements in this emerging field of gangliosidomics, with a particular emphasis on modern liquid chromatography (LC), thin-layer chromatography, hydrophilic interaction LC, and ion mobility separation coupled to high-performance MS, as well as the results generated by these systems and allied experimental procedures in profiling and structural analysis of gangliosides in healthy or diseased body fluids, such as CSF, plasma/serum, and milk. 相似文献
688.
689.
Loredana Elena Nita Alexandra Croitoriu Alexandru M. Serban Maria Bercea Alina G. Rusu Alina Ghilan Maria Butnaru Liliana Mititelu-Tartau Aurica P. Chiriac 《Macromolecular bioscience》2023,23(3):2200451
Short aromatic peptide derivatives, i.e., peptides or amino acids modified with aromatic groups, such as 9-fluorenylmethoxycarbonyl (Fmoc), can self-assemble into extracellular matrix-like hydrogels due to their nanofibrillar architecture. Among different types of amino acids, lysine (Lys) and glycine (Gly) are involved in multiple physiological processes, being key factors in the proper growth of cells, carnitine production, and collagen formation. The authors have previously successfully presented the possibility of obtaining supramolecular gels based on Fmoc-Lys-Fmoc and short peptides such as Fmoc-Gly-Gly-Gly in order to use them as a substrate for cell cultures. This paper investigates how the introduction of a gelling polymer can influence the properties of the network as well as the compatibility of the resulting materials with different cell types. A series of hydrogel compositions consisting of combinations of Fmoc-Lys-Fmoc and Fmoc-Gly-Gly-Gly with Agarose and Phytagel are thus obtained. All compositions form structured gels as shown by rheological studies and scanning electron microscopy. Fourier transform infrared spectroscopy analysis evidences the formation of H-bonds between the polysaccharides and amino acids or short peptides. Moreover, all gels exhibit good cell viability on fibroblasts as demonstrated by a live-dead staining test and good in vivo biocompatibility, which highlights the great potential of these biomaterials for biomedical applications. 相似文献