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31.
Urszula Kosikowska Monika Wujec Nazar Trotsko Wojciech Ponka Piotr Paneth Agata Paneth 《Molecules (Basel, Switzerland)》2021,26(1)
The development of drug-resistant bacteria is currently one of the major challenges in medicine. Therefore, the discovery of novel lead structures for the design of antibacterial drugs is urgently needed. In this structure–activity relationship study, a library of ortho-, meta-, and para-fluorobenzoylthiosemicarbazides, and their cyclic analogues with 1,2,4-triazole scaffold, was created and tested for antibacterial activity against Gram-positive bacteria strains. While all tested 1,2,4-triazoles were devoid of potent activity, the antibacterial response of the thiosemicarbazides was highly dependent on substitution pattern at the N4 aryl position. The optimum activity for these compounds was found for trifluoromethyl derivatives such as 15a, 15b, and 16b, which were active against both the reference strains panel, and pathogenic methicillin-sensitive and methicillin-resistant Staphylococcus aureus clinical isolates at minimal inhibitory concentrations (MICs) ranging from 7.82 to 31.25 μg/mL. Based on the binding affinities obtained from docking, the conclusion can be reached that fluorobenzoylthiosemicarbazides can be considered as potential allosteric d-alanyl-d-alanine ligase inhibitors. 相似文献
32.
Reaction of phenylpropiolic ester (I) with α- and β-tetralones in the presence of sodium ethoxide yielded 5,6-dihydro-7,8-benzflavones and ethyl β-(2-tetralon-1-yl)cinnamates, as a result of Claisen and Michael reactions, respectively. The reaction of I with 3-ethoxy-2-cyclohexen-l-one and acetylcyclopropane in the presence of sodium ethoxide yielded acetylenic β-diketones and 2-aryl-6-cyclopropylpyran-4-ones, respectively. These products were identified on the basis of spectral and analytical data. 相似文献
33.
In previous work we have postulated that highly rotationally-excited hydrides, AH, can relax by way of “cascading”, i.e., rapid vibrational exchange in which AH is vibrationally deactivated with retention of rotational quantum number (ΔvAH = ?1, ΔJAH ≈ 0). Infrared chemiluminescence studies reported here provide evidence of cascading in OH2 and HCl2 (2 symbolises vibrational excitation in the ground electronic state). The collision partners, BC, responsible for the cascading are thought to be (i) OH2 + NO2, (ii) HCl2 + NOCl and (iii) HCl2 + ICl. Extremely rapid vibrational exchange is indicative of a resonant process. Resonance must occur for a wide range of vAH and JAH, and a variety of collision partners BC. A plausible basis for such a process involves multiquantum vibrational and rotational transitions in the recipient molecule, BC, which “tune” the energy-exchange to resonance. 相似文献
34.
Saadia Shahzad Nazar Khan Zubair Nawaz Claudio Ferrero 《Journal of synchrotron radiation》2018,25(2):439-450
The accurate calibration of powder diffraction data acquired from area detectors using calibration standards is a crucial step in the data reduction process to attain high‐quality one‐dimensional patterns. A novel algorithm has been developed for extracting Debye–Scherrer rings automatically using an approach based on computer vision and pattern recognition techniques. The presented technique requires no human intervention and, unlike previous approaches, makes no restrictive assumptions on the diffraction setup and/or rings. It can detect complete rings as well as portions of them, and works on several types of diffraction images with various degrees of ring graininess, textured diffraction patterns and detector tilt with respect to the incoming beam. 相似文献
35.
Niftaliyeva Aysel Karaduman Ali Kalwar Nazar Hussain Avci Ahmet Pehlivan Erol 《Research on Chemical Intermediates》2022,48(1):145-165
Research on Chemical Intermediates - Synthesis of Ag, Ni, Cu metallic and Ag/Ni, Ag/Cu bimetallic nanoparticles (NPs) was carried out by using metal nitrate salts as precursors via an easy and... 相似文献
36.
Rodrigo Luis Silva Ribeiro Santos Rute Nazaré Fernandes Sanches 《Journal of Coordination Chemistry》2015,68(17-18):3209-3228
Diruthenium paddlewheel-structured complexes bearing a Ru2(II,III) multiply bonded core show promising potential in medicinal chemistry. This work reports studies on the interactions of the tetrakis(acetato)chloridodiruthenium(II,III) complex (RuAc), [Ru2(μ-O2CCH3)4Cl], and the corresponding Ru2(II,III)-non-steroidal anti-inflammatory drug (NSAID) metallodrugs of the NSAIDs ibuprofen (RuIbp) and ketoprofen (RuKet) with the human serum albumin (HSA). Circular dichroism (CD) studies showed that the three Ru2 complexes interact with the HSA and induce conformational changes on the secondary structure of the protein. The reaction of the RuAc complex with the protein was monitored and the RuAc/HSA binding constant was estimated on the basis of electronic absorption spectroscopy data. Fluorescence emission spectroscopy studies were performed for all the Ru2 complex/HSA systems and the Stern–Volmer constants and the thermodynamic parameters were determined for the RuAc/HSA binding. Mass spectrometry data confirmed the presence of the Ru2 complexes in the protein phase after ultrafiltration. The studies suggest that the nature of the RuAc binding to the HSA is distinct from that of the derived RuIbp and RuKet metallodrugs. Electrostatic forces, accompanied by coordination of the metal to the amino acid side chains of the protein, seem to be the main forces acting in the RuAc/HSA binding, while non-covalent/hydrophobic forces might be predominant in the Ru2-NSAID metallodrug/protein interactions. The findings suggest that the HSA protein might be a potential carrier in the blood plasma for the Ru2(II,III)-NSAID metallodrugs. 相似文献
37.
The problem of steady mixed convection boundary layer flow over a vertical impermeable flat plate in a porous medium saturated
with water at 4°C (maximum density) when the temperature of the plate varies as x
m
and the velocity outside boundary layer varies as x
2 m
, where x measures the distance from the leading edge of the plate and m is a constant is studied. Both cases of the assisting and the opposing flows are considered. The plate is aligned parallel
to a free stream velocity U
∞ oriented in the upward or downward direction, while the ambient temperature is T
∞ = T
m (temperature at maximum density). The mathematical models for this problem are formulated, analyzed and simplified, and further
transformed into non-dimensional form using non-dimensional variables. Next, the system of governing partial differential
equations is transformed into a system of ordinary differential equations using the similarity variables. The resulting system
of ordinary differential equations is solved numerically using a finite-difference method known as the Keller-box scheme.
Numerical results for the non-dimensional skin friction or shear stress, wall heat transfer, as well as the temperature profiles
are obtained and discussed for different values of the mixed convection parameter λ and the power index m. All the numerical solutions are presented in the form of tables and figures. The results show that solutions are possible
for large values of λ and m for the case of assisting flow. Dual solutions occurred for the case of opposing flow with limited admissible values of λ
and m. In addition, separation of boundary layers occurred for opposing flow, and separation is delayed for the case of water at
4°C (maximum density) compared to water at normal temperature. 相似文献
38.
Olesya Myakonkaya Dr. Zhiyong Hu Muhammad Faizan Nazar Prof. Julian Eastoe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(39):11784-11790
The stability and separation of colloids and nanoparticles has been addressed in numerous studies. Most of the work reported to date requires high cost, energy intensive approaches such as ultracentrifugation and solvent evaporation to recover the particles. At this point of time, when green science is beginning to make a real impact, it is vital to achieve efficient and effective separation and recovery of colloids to provide environmental and economic benefits. This article explores recent advances in strategies for recycling and reusing functional nanomaterials, which indicate new directions in lean engineering of high‐value nanoparticles, such as Au and Pd. 相似文献
39.
Afzal Shah Muhammad Zaheer Rumana Qureshi Zareen Akhter Muhammad Faizan Nazar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(3):1082-1087
Cyclic voltammetry (CV) coupled with UV–vis and fluorescence spectroscopy were used to probe the interaction of potential anticancer drug, 4-nitrophenylferrocene (NFC) with DNA. The electrostatic interaction of the positively charged NFC with the anionic phosphate of DNA was evidenced by the findings like negative formal potential shift in CV, ionic strength effect, smaller bathochromic shift in UV–vis spectroscopy, incomplete quenching in the emission spectra and decrease in viscosity. The diffusion coefficients of the free and DNA bound forms of the drug were evaluated from Randles–Sevcik equation. The binding parameters like binding constant, ratio of binding constants (Kred/Kox), binding site size and binding free energy were determined from voltammetric data. The binding constant was also determined from UV–vis and fluorescence spectroscopy with a value quite close to that obtained from CV. 相似文献
40.