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71.
Alina D. Zamfir Dragana Fabris Florina Capitan Cristian Munteanu Željka Vukelić Corina Flangea 《Analytical and bioanalytical chemistry》2013,405(23):7321-7335
In this preliminary investigation, a low-grade astrocytoma (AcT) is investigated by high-resolution (HR) mass spectrometry (MS) aiming at characterization of gangliosides with potential biomarker value. The research was conducted towards a comparative mapping of ganglioside expression in AcT, its surrounding tissue (ST) and a normal control brain tissue (NT). HR MS was conducted in the negative ion mode nanoelectrospray ionization (nanoESI). Fragmentation analysis was carried out by collision-induced dissociation (CID) MS2–MS4. Due to the high resolving power and mass accuracy, by comparative mapping of the ganglioside extracts from AcT, ST and NT, under identical conditions, 37 different species in AcT, 40 in ST and 56 in NT were identified. AcT and ST were found to contain 18 identical ganglioside components. Among all three specimens, ST extract presented the highest levels of sialylation, fucosylation and acetylation, a feature which might be correlated to the tumor expansion in the adjacent brain area. MS mapping indicated also that AcT, ST and NT share one doubly deprotonated molecule at m/z 1063.31, attributable to GT1(d18:1/18:0) or GT1(d18:0/18:1). CID MS2–MS4 on these particular ions detected in AcT and ST provided data supporting GT1c isomer in the investigated astrocytoma tissue. Our results show that HR MS has a remarkable potential in brain cancer research for the determination of tumor-associated markers and for their structural determination. Figure
Ganglioside isomer discrimination in human astrocytoma by Orbitrap multistage MS 相似文献
72.
73.
74.
A translation surface in the Heisenberg group Nil3 is a surface constructed by multiplying (using the group operation) two curves. We completely classify minimal translation surfaces in the Heisenberg group Nil3. 相似文献
75.
Simona Luiza Druţă-Romaniuc Jun-ichi Inoguchi Marian Ioan Munteanu Ana Irina Nistor 《Journal of Nonlinear Mathematical Physics》2013,20(3):428-447
In this paper we classify the magnetic trajectories corresponding to contact magnetic fields in Sasakian manifolds of arbitrary dimension. Moreover, when the ambient is a Sasakian space form, we prove that the codimension of the curve may be reduced to 2. This means that the magnetic curve lies on a 3-dimensional Sasakian space form, embedded as a totally geodesic submanifold of the Sasakian space form of dimension (2n+1). 相似文献
76.
Yan Chen Alina C. Munteanu Dr. Yu‐Fen Huang Dr. Joseph Phillips Dr. Zhi Zhu Michael Mavros Weihong Tan Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(21):5327-5336
Sensitive surveying : Fluorescence correlation spectroscopy (FCS) was used to study receptor density and to monitor ligand–receptor interactions on live cell membranes by the introduction of fluorescently marked aptamers, which specifically bind to certain cell‐surface receptors (see schematic representation; FITC: fluorescein isothiocyanate).
77.
Sadik Amajjahe Maricica Munteanu Helmut Ritter 《Macromolecular rapid communications》2009,30(11):904-908
Methacrylate‐modified β‐cyclodextrin (β‐CD) and methyl methacrylate (MMA) have been radically copolymerized to obtain hydrophobic CD copolymers. The water‐insoluble copolymers are able to form highly stable inclusion complexes with anions of ionic liquids. Surprisingly, the inclusion of the anions in the CD cavity results in a significant change of thermal and solution properties. Furthermore, it can be shown that the structure of the ionic liquid anions influences the coil structure of the copolymers. The obtained results could be proven by means of microcalorimetry, differential scanning calorimetry, and dynamic light scattering.
78.
On the free vibrations of a piezoceramic hollow sphere 总被引:1,自引:0,他引:1
The aim of the paper is to analyze the free vibrations of a piezoceramic hollow sphere with radial polarization. Using the cnoidal method and a genetic algorithm solves the equations of a radially inhomogeneous spherically isotropic piezoelastic medium. The Reddy and the cosine laws represent the functionally graded property of material. It is seen that for a piezoceramic hollow sphere, the piezoelectric effect consists in increasing the values for the natural frequencies in the specified classes of vibrations. 相似文献
79.
Daniela Hanganu Mihaela Niculae Irina Ielciu Neli-Kinga Olah Melania Munteanu Ramona Burtescu Rzvan tefan Loredana Olar Emoke Pall Sanda Andrei Dan C. Vodnar Daniela Benedec Ilioara Oniga 《Molecules (Basel, Switzerland)》2021,26(11)
Syringa vulgaris L. (common lilac) is one of the most popular ornamental species, but also a promising not comprehensively studied source of bioactive compounds with important therapeutic potential. Our study was designed to characterize the chemical composition and to assess the antioxidant and cytotoxic properties of ethanolic extracts obtained from S. vulgaris L. flowers, leaves, bark, and fruit. The chemical profile of the ethanolic extracts was investigated using chromatographic (HPLC-DAD-ESI+, GC-MS) and spectral (UV-Vis, FT-IR) methods, while the protective effect against free radicals was evaluated in vitro by different chemical assays (DPPH, FRAP, CUPRAC). The cytotoxic activity was tested on two tumoral cell lines, HeLa, B16F10, using the MTT assay. Significant amounts of free or glycosylated chemical components belonging to various therapeutically important structural classes, such as phenyl-propanoids (syringin, acteoside, echinacoside), flavonoids (quercetin, kaempferol derivatives) and secoiridoids (secologanoside, oleuropein, 10-hydroxy oleuropein, demethyloleuropein, syringalactone A, nuzhenide, lingstroside) were obtained for the flowers, leaves and bark extracts, respectively. Furthermore, MTT tests pointed out a significant cytotoxic potential expressed in a non-dose-dependent manner toward the tumoral lines. The performed methods underlined that S. vulgaris extracts, in particular belonging to flowers and leaves, represent valuable sources of compounds with antioxidant and antitumoral potential. 相似文献
80.
G. Munteanu P. Petrova I. Ivanov L. F. Liotta Z. Kaszkur T. Tabakova L. Ilieva 《Journal of Thermal Analysis and Calorimetry》2018,131(1):145-154
The reducibility of Au catalysts on CeO2 supports doped with 1 and 2.5 mass% Y2O3 by two types of preparation methods (impregnation and co-precipitation) has been studied by temperature-programmed reduction and compared with that of pure Au/CeO2. The kinetic parameters of reduction were determined simulating each reduction process. The capacities of these catalysts to retain oxygen have been evaluated by temperature-programmed desorption. The catalytic activities in water gas shift reaction were determined measuring CO conversion between 413 and 623 K. The catalytic performances of all these catalysts were explained in terms of mobility of the oxygen ions of the CeO2 lattice. 相似文献