排序方式: 共有55条查询结果,搜索用时 250 毫秒
31.
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
32.
Recai İnam Tuba Sarİgül Ebru Zeynep Gülerman NazlI Uncu 《International journal of environmental analytical chemistry》2013,93(15):1135-1149
A novel, sensitive, simple, fast, and fully validated differential pulse polarographic (DPP) method for the determination of trace amounts of thifensulfuron-methyl in pesticide formulation, soil, and orange juice is reported. This procedure was based on a highly sensitive peak formed due to the reduction of thifensulfuron-methyl on a dropping mercury electrode over the pH range 1.00–10.00 in Britton–Robinson buffer. The polarographic reduction exhibits only a single peak in the pH ranges pH?≥?3.0 and pH?≤?6.0 and pH?=?10.0 located at potential values of ?1.010, ?1.350, and ?1.610?V (vs. SCE), respectively. The single peak appeared as a maximum at pH 3.0 (?1.010?V) was well resolved and suitable to be investigated for analytical use. This peak showed quantitative increments with the additions of standard thifensulfuron-methyl solution under the optimal conditions, and the cathodic peak current was linearity proportional to the thifensulfuron-methyl concentration in the range of 2?×?10?7–5?×?10?5?M. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 1.05?×?10?7 and 3.50?×?10?7?M, respectively, according to the relation k ?×?SD/b (where k?=?3 for LOD, k?=?10 for LOQ, SD is the standard deviation of the blank, and b is the slope of the calibration curve). The proposed method was applied to pesticide formulation (Harmony® Extra), and the average percentage recovery was in agreement with that obtained by the spectrophotometric comparison method, 97.82 and 102.6%, respectively. The method was extended to determination of thifensulfuron-methy in spiked soil and orange juice, showing a good reproducibility and accuracy with a relative standard deviation of 4.55 and 1.40%, and relative errors of +2.80 and +1.90%, respectively. 相似文献
33.
Coir/silk fiber-reinforced polypropylene (PP) based unidirectional composites (40 wt.%) were manufactured by compression molding. Coir/silk fibers and PP sheets were treated with ultraviolet radiation at different intensities and then composites were fabricated. It was found that mechanical properties of irradiated silk/irradiated PP composites were found to increase significantly compared to the untreated ones and even higher than that of irradiated coir/irradiated PP composites. Soil degradation tests indicated that irradiated coir/irradiated PP composites significantly lost much of its mechanical properties, but irradiated silk/irradiated PP composites retained their strength of its original integrity. Scanning electron microscopy and water uptake of both types of composites were also investigated. 相似文献
34.
Haydar Göral 《Archive for Mathematical Logic》2018,57(3-4):203-237
In this paper, we study an algebraically closed field \(\Omega \) expanded by two unary predicates denoting an algebraically closed proper subfield k and a multiplicative subgroup \(\Gamma \). This will be a proper expansion of algebraically closed field with a group satisfying the Mann property, and also pairs of algebraically closed fields. We first characterize the independence in the triple \((\Omega , k, \Gamma )\). This enables us to characterize the interpretable groups when \(\Gamma \) is divisible. Every interpretable group H in \((\Omega ,k, \Gamma )\) is, up to isogeny, an extension of a direct sum of k-rational points of an algebraic group defined over k and an interpretable abelian group in \(\Gamma \) by an interpretable group N, which is the quotient of an algebraic group by a subgroup \(N_1\), which in turn is isogenous to a cartesian product of k-rational points of an algebraic group defined over k and an interpretable abelian group in \(\Gamma \). 相似文献
35.
Haydar Göral 《代数通讯》2018,46(10):4463-4472
In this study, we find height bounds in the polynomial ring over the field of algebraic numbers to test the primality of an ideal. We also obtain height bounds in the arithmetic Nullstellensatz. We apply nonstandard analysis and hence our constants will be ineffective. 相似文献
36.
A particular Temperature-Programmed Desorption (TPD) method, called ‘Intermittent TPD’, has been applied to the decomposition
of oxygen groups naturally present at the surface of a microporous active carbon. It is shown that this method provides more
information on the kinetics of the thermal decomposition of these species than the classical TPD technique. The main result
is that the decomposition of these oxygen groups occurs in at least 7 distinct stages which have been characterized by their
apparent activation energy and the corresponding frequency factor. The present study underlines the usefulness of ITPD for
studying the rate of desorption of gases from powdered samples with a strongly heterogeneous surface.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
37.
Haydar Altinok S. Keith Nixon Peter A. Gorry David Attwood Colin Booth Antonis Kelarakis Vasiliki Havredaki 《Colloids and surfaces. B, Biointerfaces》1999,16(1-4):73-91
The aqueous solution properties of five diblock copolymers prepared by sequential anionic copolymerisation (i.e. E102P37, E104P52, E92P55, E104P60 and E98P73 where E denotes oxyethylene and P denotes oxypropylene) were studied across a wide range of concentration. The techniques used to study micellisation and micellar properties in dilute solution were static and dynamic light scattering, surface tension, and eluent gel-permeation chromatography. The gelation of concentrated solutions was also investigated. As expected, the critical micelle concentration (CMC) was lowered and the association number of the micelles was increased by an increase in P-block length. In contrast, the critical gel concentration was unchanged, consistent with the constant E-block length leading to micelles with essentially identical E-block fringes. Comparison of the CMCs of the diblock copolymers with those of triblock EmPnEm copolymers with the same P-block length shows the diblock copolymers to micellise more efficiently. A similar comparison of the CMCs of the diblock copolymers with those of EmBn copolymer (B denotes oxybutylene) shows the hydrophobicity of a P unit to be one-sixth that of a B unit. The possibility is explored of correlating the limiting association number of a spherical micelle with the hydrophobe block length of its constituent copolymer. Of the five copolymers, only dilute solutions of E98P73 were predominantly micellar at both room temperature and body temperature, and this copolymer must be a prime candidate in any consideration of the potential application of EmPn copolymers in the solubilisation and controlled release of drugs. 相似文献
38.
Haydar Gral 《Mathematical Logic Quarterly》2019,65(1):14-22
In this paper, we study the field of algebraic numbers with a set of elements of small height treated as a predicate. We prove that such structures are not simple and have the independence property. A real algebraic integer is called a Salem number if α and are Galois conjugate and all other Galois conjugates of α lie on the unit circle. It is not known whether 1 is a limit point of Salem numbers. We relate the simplicity of a certain pair with Lehmer's conjecture and obtain a model‐theoretic characterization of Lehmer's conjecture for Salem numbers. 相似文献
39.
Almost periodic solutions of neutral impulsive systems with periodic time-dependent perturbed delays
Valéry Covachev Zlatinka Covacheva Haydar Akça Eada Ahmed Al-Zahrani 《Central European Journal of Mathematics》2003,1(3):292-314
A neutral impulsive system with a small delay of the argument of the derivative and another delay which differs from a constant
by a periodic perturbation of a small amplitude is considered. If the corresponding system with constant delay has an isolated
ω-periodic solution and the period of the delay is not rationally dependent on ω, then under a nondegeneracy assumption it
is proved that in any sufficiently small neighbourhood of this orbit the perturbed system has a unique almost periodic solution. 相似文献
40.
A series of copolyesters were synthesized by melt‐polycondensation reaction of poly(ethylene terephtalate) (PET) with various proportions of equimolar compositions of p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA) and terephtalic acid (TPA). Viscosity, liquid crystallinity, thermal properties, degree of crystallinity and thermal stabilitiy of these copolyesters were investigated by Ubbelohde viscometer, hot‐stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and thermogravimetric analysis (TGA), respectively. On the basis of viscosity measurement, it was observed that intrinsic viscosity values of the copolyesters are increased regularly with increasing amounts of aromatic units (p‐ABA, HQDA and TPA) in the polymer chain. Thermotropic liquid crystalline behavior was observed in the copolyesters containing over 50 mol% of rigid p‐ABA/HQDA/TPA aromatic units. DSC analysis of the anisotropic copolyesters revealed broad and weak endotherms associated with the nematic phases, and the melting temperatures were found to be in the processable region. As the mol% of PET in the polymer chain increased, the specific enthalpies of fusion and the degree of crystallinity of the copolyesters were also increased regularly. 相似文献