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41.
A new, green, and highly efficient protocol for the expeditious preparation of some α,α′-bis[(aryl or allyl)idene]cycloalkanones and 2-[(aryl or allyl)idene]-1-indanones via a simple microwave-assisted Claisen–Schmidt condensation reaction catalyzed by MoCl5 was successfully developed. Outstanding features of the current methodology include the use of solvent-free conditions, simple operation, use of a very inexpensive and available catalyst, low catalyst loading, short reaction times, high yields of the pure products, no harmful by-products, easy workup, and also the applicability of microwave irradiation as a clean source of energy. Furthermore, a gram-scale reaction was successfully conducted, proving the scalability of this current Claisen–Schmidt condensation reaction. 相似文献
42.
Moradi Sima Shareghi Behzad Saboury Ali Akbar 《Monatshefte für Chemie / Chemical Monthly》2020,151(4):637-647
Monatshefte für Chemie - Chemical Monthly - In this study, the structure and stability of acid phosphatase in its interaction with Co3O4 nanoparticles are evaluated through absorbance, enzyme... 相似文献
43.
Ali Golchin Simzar Hosseinzadeh Aytak Jouybar Masumeh Staji Masoud Soleimani Abdolreza Ardeshirylajimi Arash Khojasteh 《先进技术聚合物》2020,31(7):1519-1531
Wound healing, one of the most complex processes of the body involving the cooperation of several important biomolecules and pathways, is one of the major therapeutic and economic issues in regenerative medicine. The present study aimed to introduce a novel electrospun curcumin (Cur)‐incorporated chitosan/polyvinyl alcohol/carbopol/polycaprolactone nanofibrous composite for concurrent delivery of the buccal fat pad‐derived mesenchymal stem cells (BFP‐MSCs) and Cur to a full‐thickness wound on the mouse model. Scaffolds were characterized structurally using scanning electron microscopy (SEM), fluorescence microscopy imaging and Fourier‐transform infrared spectroscopy, and toxicity of the scaffolds was also evaluated after BFP‐MSC seeding by SEM imaging and 3‐(4,5 dimethyiazol‐2‐1)‐2‐5‐diphenyl tetrazolium bromide (MTT) assay. Then, its influence on the wound‐healing process was investigated as a wound dressing for a full‐thickness skin defect in mouse model. Results demonstrated that the designed composite scaffolds have the capability for cell seeding and support their growth and proliferation. Macroscopic and histopathological characteristics were evaluated at the end of the 7 and 14 days after surgery, and their results showed that our designed scaffold groups accelerated the wound‐healing process compared with the control group. Among those, scaffold/Cur, scaffold/Cur/BFP‐MSC and scaffold/BFP‐MSC groups demonstrated more wound repair efficacy. These results indicated that the combined grafts can be used to improve the wound‐healing process, and therefore, the electrospun nanofibers presented in this study, Cur and BFP‐MSC together, were demonstrated to have promising potential for wound‐dressing applications. 相似文献
44.
Here, an electrochemical sensor based on CeO2‐SnO2/Pd was prepared and used for highly selective and sensitive determination of nitrite in some real samples. This nanocomposite was characterized by various methods like X‐ray photoelectron spectroscopy, X‐ray diffraction, energy dispersive spectroscopy, Fourier‐transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The electrochemical behavior of the sensor was evaluated by cyclic voltammetry. The results showed excellent catalytic property of the nanocomposite as a an electrocatalyst for nitrite oxidation. In the following, the experimental parameters affecting the analytical signal for nitrite were optimized. Under the optimal conditions, the limit of detection and sensitivity of the sensor were calculated as 0.10 μM and 652.95 μA.mM?1.cm?2, respectively. Also, the response of the sensor was linear in the range of 0.36 to 2200 μM of nitrite. Finally, some of the inherent features of the sensor such as repeatability, reproducibility and stability were examined after evaluation of the sensor selectivity in the presence of several interfering species. 相似文献
45.
McLachlan N Nigjeh BK Hasell A 《The Journal of the Acoustical Society of America》2003,114(1):505-511
Musical bells have had limited application due to the presence of inharmonic partials in the lower part of their acoustic spectra. A series of bells has been designed that contains up to seven partial frequencies in the harmonic series beginning at the fundamental frequency. This was achieved by choosing geometries for finite-element analysis models in which as many purely circumferential bending modes as possible occurred at frequencies below any mode with an axial ring node. The bell models were then fine tuned using gradient projection method shape optimization and the resulting profiles were cast in silicon bronze. A range of bell geometries and timbres is analyzed using psycho-acoustic models and is discussed in relation to European carillon bells. 相似文献
46.
Behzad Khorshidi 《Journal of Geometry》2009,96(1-2):81-91
A direct and easy general method is described for finding the center of gravity of all types of convex and concave polygons such as quadrilaterals, pentagons, hexagons and n-sided polygons. 相似文献
47.
Paula Walser Peter Renold Victor N'Goka Fatemeh Hosseinzadeh Christoph Tamm 《Helvetica chimica acta》1991,74(8):1941-1952
The hydrolysis of the meso-cyclopropane-1,2-dicarboxylates 1a - 3a , 4 , 5a , 6a , and 9 , containing various substituents at C(3), and of the rac-3-phenylcyclopropane-1,2-dicarboxylates 7a , 8a , and 10 with pig liver esterase (PLE) is described. The stereoselectivtty and absolute configurations of the products were determined. An interpretation of results was attempted on the basis of a recent active-site model for PLE. 相似文献
48.
Mostafa Kiamehr Batoul Alipour Leyla Mohammadkhani Behzad Jafari Peter Langer 《Tetrahedron》2017,73(21):3040-3047
Various novel polycyclic thiopyranoindol annulated [3,4-c]quinolone derivatives were synthesized via domino Knoevenagel-hetero-Diels–Alder reactions of indoline-2-thions and novel N-acrylated anthranilaldehydes in refluxing ethanol as a solvent in the presence of 20 mol% ZnBr2 as a Lewis acid catalyst. All reactions proceed with high yields with excellent regio- and stereoselectivity. 相似文献
49.
Hamid Beyzaei Mohammadreza Moghaddam-Manesh Reza Aryan Behzad Ghasemi Alireza Samzadeh-Kermani 《Chemical Papers》2017,71(9):1685-1691
Pyrazolo[3,4-d]pyrimidines are one of the most important classes of fused heterocyclic compounds which exhibit a broad range of biological and medicinal properties. They are known as anticancer, antifungal, antibacterial, antiviral and anti-inflammatory agents. In this study, some new 6-substituted 4-amino-pyrazolo[3,4-d]pyrimidine derivatives were prepared via reaction of 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile with various nitriles in the presence of sodium ethoxide as catalyst. The inhibitory properties of synthesized compounds were studied according to CLSI guidelines against some pathogenic bacteria including four gram-positive strains (Streptococcus pyogenes, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis subsp. spizizenii) and three gram-negative strains (Pseudomonas aeruginosa, Shigella flexneri and Salmonella enterica subsp. enterica). The antibacterial effects of all derivatives were compared with those of antibiotics belonging to different classes. The values were reported as inhibition zone diameter (IZD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The effect of substituents on the biological activity of derivatives was discussed as well. The inhibitory effect of compound 6a, was shown to be the most, with MIC values in the range of 32–4096 μg/mL. Since most of the synthesized compounds were effective against Streptococcus pyogenes and Pseudomonas aeruginosa, they can be considered as inhibitors of these two bacteria. 相似文献
50.
<正>A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields.The reaction took place in refluxing dioxane and does not require any catalyst or additives. 相似文献