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81.
The interaction among the reacting species in the NO-CO reaction on a metal catalytic surface that proceeds according to the Langmuir-Hinshelwood thermal mechanism is studied by means of Monte Carlo simulations. The study of this system is essential for the understanding of the influence of impurities on the catalytic oxidation of NO by CO. It is found that this complex system exhibits irreversible phase transitions between active states with sustained reaction and poisoned states without reaction. The same system has also been investigated by non-thermal (Eley-Rideal) mechanism. Both the phase diagrams of the surface coverage and the steady state production of CO2 and N2 are evaluated as a function of the partial pressures of the reactants in the gas phase. From this study, it is observed that with the increase of impurities, the production rate reduces and the reaction stops at a certain point. Moreover, the first order transition in the phase diagram converts into second order phase transition that is in accordance with the experimental findings. Therefore, the first order phase transition, which is a characteristic of such catalytic reactions, is eliminated. 相似文献
82.
The nonlocal surface plasmon spectrum in a quantizing magnetic field perpendicular to the surface has been found to have branches analogous to ‘Bernstein’ modes near multiples of the cyclotron frequency. The n=2 nonlocal surface ‘Bernstein’ mode is evaluated for low wavenumber, incorporating Landau quantization effects for degenerate and nondegenerate cases. 相似文献
83.
Kayed A. Abu Safieh Mustafa M. El‐Abadelah Musa H. Abu Zarga Salim S. Sabri Wolfgang Voelter Ccilia M. M
ssmer 《Journal of heterocyclic chemistry》2001,38(3):623-628
The synthesis of some new pyrazolo[3′,4′:6,7]azepino[5,4,3‐cd] indoles (10a‐c) was achieved via regios‐elective cyclization of the respective 3‐(4‐acylaminopyrazol‐5‐yl)indoles (9a‐c) under Bischler‐Napieralski reaction conditions. The latter compounds were obtained by acylation of the corresponding 3‐(4‐aminopyra‐zol‐5‐yl)indoles (8a,b) which, in turn, were prepared by reduction of the 3‐(4‐nitropyrazol‐5‐yl)indoles precursors (7a,b) . The latter synthons were accessible from the reaction of indolylzinc chlorides (5a,b) with 5‐chloro‐1,3‐dimethyl‐4‐nitropyrazole. Ms and nmr spectral data of 10a‐c are in agreement with the assigned azepino‐indole structure as determined for 10a by X‐ray crystal measurements which demonstrate that the azepine ring is almost completely planar with the indole and pyrazole rings. 相似文献
84.
Michael A. Tallon Yulia Rogan Bilal Marie Raymond Clark Osama M. Musa Ezat Khosravi 《Journal of polymer science. Part A, Polymer chemistry》2014,52(17):2477-2501
The physiochemical properties, comonomer sequencing, and regiospecificity of the linkages between monomeric units within homo/copolymers based on 5,6‐di‐substituted norbornene and 7‐oxanorbornene type monomers by ring‐opening metathesis polymerization are reported and correlated to their primary and secondary structural elements. In general, first‐generation Grubbs‐ I1 ruthenium catalyst generates polymers with high trans content that exhibits an extended secondary structure with exo,exo substituents, whereas second‐generation Grubbs‐ I2 catalyst produces polymers with high cis content that forms tight turns, resulting in a compact structure. Furthermore, I2 ‐produced polymers exhibit a high level of alternating cis–trans double bonds along their polymeric backbone. In stark contrast, both first‐ and second‐generation Grubbs catalysts display complete reversal in cis/trans selectivity when an oxygen atom is in position‐7 of the norbornene‐ring along with mono‐endo‐substitution in position‐5 or 6, and hence highlighting the importance of stereoelectronic complexation by the catalyst with the next incoming monomer for cis/trans selectivity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2477–2501 相似文献
85.
Murat Erdemoğlu Musa Sarıkaya Mehmet Canbazoğlu 《Journal of Dispersion Science and Technology》2013,34(4):439-442
Leaching of celestite mineral, SrSO4, with sodium sulfide, Na2S, was investigated from the point of strontium carbonate, SrCO3, production. Experiments were carried out to explain the conversion mechanism of celestite to strontium disulfide, SrS2, in Na2S solution. Effects of stirring speed, particle size, and concentration of Na2S on conversion were studied at constant temperature and solid‐to‐liquid ratio. The results showed that the rate of conversion mainly depends on Na2S concentration. It was concluded that leaching of celestite in Na2S solution for conversion to SrS2 is possible but slow. 相似文献
86.
Musa Şahin Bahri Ülküseven 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):545-554
Abstract The template reactions of salicylidene-, 5-bromosalicylidene-, and 3,5-dichlorosalicylidene-S-R-thiosemicarbazone (R: propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, dodecyl) with 5-bromo- and 3,5-dichlorosalicylaldehyde in the presence of nickel(II) yielded N1,N4-diarylidene-S-alkyl-thiosemicarbazone chelates. The N2O2 type complexes were isolated as stable solid compounds and characterized by elemental analysis, electronic, infrared, 1H NMR, and mass spectroscopies. The magnetic susceptibility measurements at room temperature (r.t.) indicate the diamagnetic nature of the complexes. The relationship between melting point (mp) values of the nickel(II) template complexes and the chain length of alkyl moiety was clearly shown. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the related elements to view the free supplemental file. 相似文献
87.
Huseyin Bekir Yildiz Dilek Odaci Demirkol Serkan Sayin Mustafa Yilmaz Ozcan Koysuren Musa Kamaci 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1075-1084
Accumulation of cholesterol in human blood can cause several health problems such as heart disease, coronary artery disease, arteriosclerosis, hypertension, cerebral thrombosis, etc. Therefore, simple and fast cholesterol determination in blood is clinically important. In this study, two types of amperometric cholesterol biosensors were designed by physically entrapping cholesterol oxidase in conducting polymers; thiophene capped poly(ethyleneoxide)/polypyrrole (PEO-co-PPy) and 3-methylthienyl methacrylate-co-p-vinyl benzyloxy poly(ethyleneoxide)/polypyrrole (CP-co-PPy). PEO-co-PPy and CP-co-PPy were synthesized electrochemically and cholesterol oxidase was immobilized by entrapment during electropolymerization. The amperometric responses of the enzyme electrodes were measured by monitoring oxidation current of H2O2 at +0.7 V in the absence of a mediator. Kinetic parameters, such as Km and Imax, operational and storage stabilities, effects of pH and temperature were determined for both entrapment supports. Km values were found as 1.47 and 5.16 mM for PEO-co-PPy and CP-co-PPy enzyme electrodes, respectively. By using these Km values, it can be observed that ChOx immobilized in PEO-co-PPy shows higher affinity towards the substrate. 相似文献
88.
Musa I. El-Barghouthi Hamzeh M. Abdel-Halim Feryal J. Haj-Ibrahim Khaleel I. Assaf 《Supramolecular chemistry》2013,25(1-2):80-89
Molecular dynamics (MD) simulations were performed for cucurbit[6]uril (CB6) methyl and cyclohexyl derivatives in aqueous solutions. Furthermore, MD simulations have been conducted to study the inclusion complexes between each CB6 derivative with α,ω-pentane diammonium ion (NH3+(CH2)5NH3+) to estimate the binding free energies, the complex geometries and the intermolecular forces responsible for complex formation. Results show a complete inclusion of the guest molecule in the cavity of the host for all complexes. Results also indicate that the guest dynamics inside the cavity of the substituted host is similar to that for the unsubstituted host. This demonstrates that the molecular recognition of the host is not affected by the alkyl substitution at the equator. Also, there is an insignificant conformational change of the macrocyclic structure upon inclusion of the guest. Molecular mechanics/Poisson Boltzmann surface area method was used to estimate the binding free energy of each complex. Results indicate that host–guest electrostatic interactions make the largest contribution to the complex binding free energy. Moreover, van der Waals interactions add significantly to the complex stability. The guest molecules show more or less similar binding free energies with the substituted CB6 that exhibits slightly more negative values than unsubstituted CB6 which is proved also by umbrella sampling. 相似文献
89.
A. Y. Musa W. Ahmoda A. A. Al-Amiery A. A. H. Kadhum A. B. Mohamad 《Journal of Structural Chemistry》2013,54(2):301-308
The effects of the molecular structure on the corrosion inhibition efficiency are investigated by nine methods of calculations. The selected thio compounds were previously identified as corrosion inhibitors for mild steel in the 1.0 M HCl solution. The electronic properties such as highest occupied molecular orbital (EHOMO) energy, lowest unoccupied molecular orbital (ELUMO) energy, dipole moment (μ), and Fukui indices are calculated and discussed. Results show that the corrosion inhibition efficiency increase with the increase in both EHOMO and μ values, respectively, and decrease in ELUMO. QSAR approach is utilized in this study; a good relationship is found between the experimental corrosion inhibition efficiency (IEexp, %) and the theoretical corrosion inhibition efficiency (IEtheor, %). The calculated inhibition efficiency is found closer to the experimental inhibition efficiency with a coefficient of correlation (R 2) of 0.875. 相似文献
90.
Arafa Musa Ehab M. Mostafa Syed Nasir Abbas Bukhari Nasser Hadal Alotaibi Ahmed H. El-Ghorab Amr Farouk AbdElAziz A. Nayl Mohammed M. Ghoneim Mohamed A. Abdelgawad 《Molecules (Basel, Switzerland)》2022,27(4)
For most researchers, discovering new anticancer drugs to avoid the adverse effects of current ones, to improve therapeutic benefits and to reduce resistance is essential. Because the COX-2 enzyme plays an important role in various types of cancer leading to malignancy enhancement, inhibition of apoptosis, and tumor-cell metastasis, an indispensable objective is to design new scaffolds or drugs that possess combined action or dual effect, such as kinase and COX-2 inhibition. The start compounds A1 to A6 were prepared through the diazo coupling of 3-aminoacetophenone with a corresponding phenol and then condensed with two new chalcone series, C7–18. The newly synthesized compounds were assessed against both COX-2 and epidermal growth factor receptor (EGFR) for their inhibitory effect. All novel compounds were screened for cytotoxicity against five cancer cell lines. Compounds C9 and G10 exhibited potent EGFR inhibition with IC50 values of 0.8 and 1.1 µM, respectively. Additionally, they also displayed great COX-2 inhibition with IC50 values of 1.27 and 1.88 µM, respectively. Furthermore, the target compounds were assessed for their cytotoxicity against pancreatic ductal cancer (Panc-1), lung cancer (H-460), human colon cancer (HT-29), human malignant melanoma (A375) and pancreatic cancer (PaCa-2) cell lines. Interestingly, compounds C10 and G12 exhibited the strongest cytotoxic effect against PaCa-2 with average IC50 values of 0.9 and 0.8 µM, respectively. To understand the possible binding modes of the compounds under investigation with the receptor cites of EGFR and COX-2, a virtual docking study was conducted. 相似文献