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71.
Marina Zveaghintseva Eugenia Stingaci Serghei Pogrebnoi Anastasia Smetanscaia Vladimir Valica Livia Uncu Victor Ch. Kravtsov Elena Melnic Anthi Petrou Jasmina Glamo
lija Marina Sokovi Alejandro Carazo Pemysl Mladnka Vladimir Poroikov Athina Geronikaki Fliur Z. Macaev 《Molecules (Basel, Switzerland)》2021,26(14)
Herein we report the synthesis of some new 1H-1,2,4-triazole functionalized chromenols (3a–3n) via tandem reactions of 1-(alkyl/aryl)-2-(1H-1,2,4-triazole-1-yl) with salicylic aldehydes and the evaluation of their antifungal activity. In silico prediction of biological activity with computer program PASS indicate that the compounds have a high novelty compared to the known antifungal agents. We did not find any close analog among the over 580,000 pharmaceutical agents in the Cortellis Drug Discovery Intelligence database at the similarity cutoff of 70%. The evaluation of antifungal activity in vitro revealed that the highest activity was exhibited by compound 3k, followed by 3n. Their MIC values for different fungi were 22.1–184.2 and 71.3–199.8 µM, respectively. Twelve from fourteen tested compounds were more active than the reference drugs ketoconazole and bifonazole. The most sensitive fungus appeared to be Trichoderma viride, while Aspergillus fumigatus was the most resistant one. It was found that the presence of the 2-(tert-butyl)-2H-chromen-2-ol substituent on the 4th position of the triazole ring is very beneficial for antifungal activity. Molecular docking studies on C. albicans sterol 14α-demethylase (CYP51) and DNA topoisomerase IV were used to predict the mechanism of antifungal activities. According to the docking results, the inhibition of CYP51 is a putative mechanism of antifungal activity of the novel chromenol derivatives. We also showed that most active compounds have a low cytotoxicity, which allows us to consider them promising antifungal agents for the subsequent testing activity in in vivo assays. 相似文献
72.
We describe how mammalian olfactory receptors (ORs) could be used as sensing elements of highly specific and sensitive bioelectronic noses. An OR and an appropriate G(alpha) protein were co-expressed in Saccharomyces cerevisiae cells from which membrane nanosomes were prepared, and immobilized on a sensor chip. By Surface Plasmon Resonance, we were able to quantitatively evaluate OR stimulation by an odorant, and G protein activation. We demonstrate that ORs in nanosomes discriminate between odorant ligands and unrelated odorants, as in whole cells. This assay also provides the possibility for quantitative assessment of the coupling efficiency of the OR with different G(alpha) subunits, without the interference of the cellular transduction pathway. Our findings will be useful to develop a new generation of electronic noses for detection and discrimination of volatile compounds, particularly amenable to micro- and nano-sensor formats. 相似文献
73.
Jasmina Obradovic Holger Wondraczek Pedro Fardim Lippo Lassila Patrick Navard 《Cellulose (London, England)》2014,21(6):4029-4038
Three-dimensionally shaped cellulosic objects were produced via a two-step procedure: swelling of softwood pulp (93 % cellulose; 4.5 % hemicellulose; 54 % crystallinity) in DMAc/LiCl followed by moulding. Swollen cellulose pulp in the form of gel was solidified with two different anti-solvents: distilled water and a combination of 2-propanol and deionized water. The solid cellulose material was further moulded in a custom-built prototype mould. The role of the anti-solvent was to solidify the swollen cellulose fibres and prepare mouldable solid specimens. The anti-solvent was chosen based on the following criteria, viz., recoverability, stable chemical reactivity, availability, cost and previous research in the anti-solvent area. The choice of solidification solvent had a great influence on the structure and mechanical properties of the final cellulose material. Results of different characterisation techniques showed that when the cellulose gel was washed with distilled water, it had a significantly higher number of lithium cations (ICP-MS and Raman), amorphous structure (X-ray) and lower mechanical properties (nanoindentation) compared to samples washed with a combination of 2-propanol and deionized water. An increase in viscosity as previously reported and changes in the NMR and IR spectra of DMAc upon LiCl suggested the formation of an ion-dipol complex, where lithium cations reside adjacent to the oxygen of the carbonyl group of DMAc. The formed macrocation [DMAcn + Li]+ was preserved between cellulose chains in cellulose specimens washed with distilled water and had an essential role in the disruption of initial bonds, thus enhancing mouldability. Electron microscopy (FE-SEM) studies showed that the surface of cellulose after mechanochemical treatment was rough with no presence of fibres. 相似文献
74.
Hojjat Madadi Mahdi Mohammadi Jasmina Casals‐Terré Roberto Castilla López 《Electrophoresis》2013,34(22-23):3126-3132
PDMS is one of the most common materials used for the flow delivery in the microfluidics chips, since it is clear, inert, nontoxic, and nonflammable. Its inexpensiveness, straightforward fabrication, and biological compatibility have made it a favorite material in the exploratory stages of the bio‐microfluidic devices. If small footprint assays want to be performed while keeping the throughput, high pressure‐rated channels should be used, but PDMS flexibility causes an important issue since it can generate a large variation of microchannel geometry. In this work, a novel fabrication technique based on the prevention of PDMS deformation is developed. A photo‐sensible thiolene resin (Norland Optical Adhesive 63, NOA 63) is used to create a rigid coating layer over the stiff PDMS micropillar array, which significantly reduces the pressure‐induced shape changes. This method uses the exact same soft lithography manufacturing equipment. The verification of the presented technique was investigated experimentally and numerically and the manufactured samples showed a deformation 70% lower than PDMS conventional samples. 相似文献
75.
Two types of bismuth modified electrodes, a bismuth-film modified glassy carbon (BiF-GCE) and a bismuth bulk modified carbon paste, were applied for the determination of selected nitroguanidine neonicotinoid insecticides. The method based on an ex situ prepared BiF-GCE operated in the differential pulse voltammetric (DPV) mode was applied to determine clothianidin in the concentration range from 2.5 to 23 μg cm?3 with a relative standard deviation (RSD) not exceeding 1.5%. The tricresyl phosphate-based carbon paste electrodes (TCP-CPEs), bulk modified with 5 and 20 w/w% of bismuth, showed a different analytical performance in the determination of imidacloprid, regarding the peak shape, potential window, and noise level. The TCP-CPE with 5% Bi was advantageous, and the developed DPV method based on it allowed the determination in the concentration range from 1.7 to 60 μg cm?3 with an RSD of 2.4%. To get a deeper insight into the morphology of the bismuth-based sensor surfaces, scanning electron microscopic measurements were performed of both the surface film and the bulk modified electrodes. 相似文献
76.
Petreska J Stefkov G Kulevanova S Alipieva K Bankova V Stefova M 《Natural product communications》2011,6(1):21-30
Twenty-one samples of Sideritis species (S. scardica, S. raeseri, S. taurica, S. syriaca and S. perfoliata) from various locations on the Balkan Peninsula were evaluated for their chemical constituents. Chemical analyses were focused on secondary metabolites, particularly phenolic compounds, which have several roles in the plant physiological processes and have demonstrated significant health beneficial effects. The occurrence of hydroxycinnamic acids, phenylethanoid glycosides and flavonoids has been investigated in taxonomically related taxa of the genus Sideritis. A systematic method for phenolic compounds identification was developed using tandem mass spectrometry coupled to high performance liquid chromatography with diode array detection. Scanning for precursor ions of commonly found phenolics in Sideritis species using LC/MS11 with an ion trap instrument permitted the specific determination of hydroxycinnamic acid derivatives, and phenylethanoid and flavonoid glycosides. Further characterization of each phenolic compound was performed using MS/MS product-ion analysis and common-neutral-loss analysis. This on-line technique allowed identification of three hydroxycinnamic acid derivatives, eight phenylethanoid glycosides, and twenty-four flavonoid glycosides. All the taxa analysed produced very similar phenolic patterns characterized by the presence of 5-caffeoylquinic acid, lavandulifolioside, verbascoside, hypolaetin 7-O-[6'-O-acetyl]-allosyl(1-->2)glucoside, apigenin 7-(4"-p-coumaroylglucoside), 4'-O-methylisoscutellarein 7-O-[6'-O-acetyl]-allosyl(1-->2)glucoside, and minor amounts of isoverbascoside, apigenin 7-O-allosyl(1-->2)glucoside, isoscutellarein 7-O-allosyl-(1-->2)-[6"-O-acetyl]-glucoside, hypolaetin 7-O-allosyl-(1-->2)-[6"-O-acetyl]-glucoside and 4'-O-methylhypolaetin 7-O-[6'-O-acetyl]-allosyl-(1-->2)-[6"-O-acetyl]-glucoside. These results show that the investigated species are systematically very closely related. Phenylethanoid glycosides and flavonoid acetylglycosides are dominant and constitute 90% of the total phenolic compounds compared with hydroxycinnamic acid and flavonoid 7-O-glycosides. Principal component analysis (PCA) was performed for the nature and content of the different compounds to be correlated to the particular Sideritis species and also to the locations. 相似文献
77.
Petreska J Stefova M Ferreres F Moreno DA Tomás-Barberán FA Stefkov G Kulevanova S Gil-Izquierdo A 《Natural product communications》2011,6(9):1305-1314
This work was afforded from 2 points of view, phytochemical evaluation and relation to antioxidant activity and dietary burden of phenolics of a cup of "Mountain tea", a drink obtained by domestic infusion of Sideritis. Phytochemically, two extraction protocols using water and methanol as solvent were used for comparison. Methanol and boiling water extracts (by domestic infusion procedure) showed that extracts were rich in bound forms of phenolics such as hydroxycinnamic acids, phenylethanoid glycosides and flavonoid glycosides. The total phenolic content for Sideritis species ranged around 190 mg per serving (2 g infusion bag) for methanol extracts and around 72 mg per serving in water extracts. Among the two different Macedonian Sideritis species, Sideritis raeseri (wild growing) showed the highest phenolics content in both extracts (212 mg and 89 mg per serving, respectively). Concerning the phenolic content in the different aerial parts, leaf was the richest plant organ in phenolics followed by flower and stem with the lowest amount. The methanol extract from Sideritis raeseri (wild growing) showed the highest antioxidant capacity as shown by DPPH, ABTS and FRAP assays. The antioxidant capacity was linearly correlated with phenolic content. Nutritionally, the dietary burden of phenolics of a "Mountain tea" bag for domestic infusion (serving size) was established at 89 mg for an homogeneous and equal distribution of the different aerial parts (leaf, flower and stem). However, and according to our results a rate of 60% leaf and 40% flower would increase the content of bioavailable phenolics and also the total phenolics content of a serving bag of "Mountain tea". 相似文献
78.
The packing chromatic number \(\chi _{\rho }(G)\) of a graph G is the smallest integer k such that the vertex set of G can be partitioned into sets \(V_i\), \(i\in \{1,\ldots ,k\}\), where each \(V_i\) is an i-packing. In this paper, we consider the packing chromatic number of several families of Sierpiński-type graphs. While it is known that this number is bounded from above by 8 in the family of Sierpiński graphs with base 3, we prove that it is unbounded in the families of Sierpiński graphs with bases greater than 3. On the other hand, we prove that the packing chromatic number in the family of Sierpiński triangle graphs \(ST^n_3\) is bounded from above by 31. Furthermore, we establish or provide bounds for the packing chromatic numbers of generalized Sierpiński graphs \(S^n_G\) with respect to all connected graphs G of order 4. 相似文献
79.
Kireeff Covo M Molvik AW Friedman A Vay JL Seidl PA Logan G Baca D Vujic JL 《Physical review letters》2006,97(5):054801
Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse. 相似文献
80.
Dušan S. Dimić Dejan A. Milenković Jasmina M. Dimitrić Marković 《Molecular physics》2018,116(9):1166-1178
The antiradical potency of catecholamines (dopamine, epinephrine, norepinephrine, L-DOPA), metabolites of dopamine (homovanillic acid, 3-methoxytyramine and 3,4-dihydroxyphenylacetic acid) and catechol towards substituted methylperoxy radicals is investigated. The thermodynamic parameters, together with the kinetic approach, are used to determine the most probable mechanism of action. The natural bond orbital and quantum theory of atoms in molecules are utilised to explain the highest reactivity of trichloromethylperoxy radical. The preferred mechanism is dependent both on the thermodynamic and kinetic parameters . The number of chlorine atoms on radical, the presence of intra-molecular hydrogen bond and number of hydroxy groups attached to the aromatic ring significantly influence the mechanism. The results suggest that sequential proton loss electron transfer (SPLET) is the most probable for reaction with methylperoxy and hydrogen atom transfer (HAT) for reaction with trichloromethylperoxy radicals, with a gradual transition between SPLET and HAT for other two radicals. Due to the significant deprotonation of molecules containing the carboxyl group, the respective anions are also investigated. The HAT and SPLET mechanisms are highly competitive in reaction with MP radical, while the dominant mechanism towards chlorinated radicals is HAT. The reactions in methanol and benzene are also discussed. 相似文献