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排序方式: 共有921条查询结果,搜索用时 15 毫秒
1.
Bahareh Heidari Majid M. Heravi Mohammad Reza Nabid Roya Sedghi Seyyed Emad Hooshmand 《应用有机金属化学》2019,33(1)
A novel nanocatalyst was designed and prepared. Initially, the surface of magnetic graphene oxide (M‐GO) was modified using thionyl chloride, tris(hydroxymethyl)aminomethane and acryloyl chloride as linkers which provide reactive C═C bonds for the polymerization of vinylic monomers. Separately, β‐cyclodextrin (β‐CD) was treated with acryloyl chloride to provide a modified β‐CD. Then, in the presence methylenebisacrylamide as a cross‐linker, monomers of modified β‐CD and acrylamide were polymerized on the surface of the pre‐prepared M‐GO. Finally, palladium acetate and sodium borohydride were added to this composite to afford supported palladium nanoparticles. This fabricated nanocomposite was fully characterized using various techniques. The efficiency of this easily separable and reusable heterogeneous catalyst was successfully examined in Suzuki–Miyaura cross‐coupling reactions of aryl halides and boronic acid as well as in modified Suzuki–Miyaura cross‐coupling reactions of N‐acylsuccinimides and boronic acid in green media. The results showed that the nanocatalyst was efficient in coupling reactions for direct formation of the corresponding biphenyl as well as benzophenone derivatives in green media based on bio‐based solvents. In addition, the nanocatalyst was easily separable, using an external magnet, and could be reused several times without significant loss of activity under the optimum reaction conditions. 相似文献
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CoFe2O4@SiO2‐CPTES‐Guanidine‐Cu(II) magnetic nanoparticles were synthesized and used as a new, inexpensive and efficient heterogeneous catalyst for the synthesis of polyhydroquinolines and 2,3‐dihydroquinazoline‐4(1H)‐ones and for the oxidation of sulfides. The structure of this nanocatalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, X‐ray diffraction and inductively coupled plasma optical emission spectrometry. Simple preparation, high catalytic activity, simple operation, high yields, use of green solvents, easy magnetic separation and reusability of the catalyst are some of the advantages of this protocol. 相似文献
3.
In this study, nanocrystalline cellulose (NCC) prepared from microcrystalline cellulose using high‐intensity ultrasonication as mechanical method without any chemical treatment. The obtained NCC with around 30–50 nm diameters, utilized as support, reducing and stabilizing agent for in‐situ green and eco‐friendly synthesis of silver nanoparticles (Ag NPs). The catalytic activity of composite was examined for degradation of environmental pollutants. The structure of as‐synthesized composite (Ag@NCC) was characterized by ultraviolet–visible spectroscopy (UV–vis), field emission scanning electron microscopy (FE‐SEM); Transmission electron microscopy (TEM); Energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). The results of the catalytic reaction experiments showed that spherically shaped silver nanoparticles of around 20 nm distributed on the surface of nanocellulose demonstrated high catalytic efficiency towards the removal of methyl orange (MO) and 4‐nitrophenol (4‐NP). 相似文献
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Farrahi Gholam Hossein Javanbakht Mahdi Jafarzadeh Hossein 《Continuum Mechanics and Thermodynamics》2020,32(3):589-606
Continuum Mechanics and Thermodynamics - A thermodynamically consistent phase field model for crack propagation is analyzed. The thermodynamic driving force for the crack propagation is derived... 相似文献
9.
Behnam Mahdavi Sogand Paydarfard Mohammad Mahdi Zangeneh Samaneh Goorani Niloofar Seydi Akram Zangeneh 《应用有机金属化学》2020,34(1):e5248
In recent decades, nanotechnology is growing rapidly owing to its widespread application in medical science. The aim of the experiment was the evaluation of cytotoxicity, antioxidant, antibacterial, antifungal, and cutaneous wound healing activities of green synthesized manganese nanoparticles using Ziziphora clinopodioides Lam leaves (MnNPs@ZC). The synthesized MnNPs@ZC were characterized using different techniques including UV–Vis., FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). According to the XRD analysis, 48.10 nm was measured for the crystal size of nanoparticles. SEM images exhibited a uniform spherical morphology and size in the range of 47.58 to 70.26 nm for the biosynthesized nanoparticles. MnNPs@ZC revealed excellent non-cytotoxicity effect against human umbilical vein endothelial cells, antioxidant activity against DPPH, antibacterial properties against Gram-negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli O157:H7) and Gram-positive bacteria (Streptococcus pneumonia, Staphylococcus aureus, and Bacillus subtilis), and antifungal potentials against Candida glabrata, Candida albicans, Candida guilliermondii, and Candida krusei. Also, use of MnNPs@ZC ointment decreased significantly (p ≤ 0.01) the wound area, total cells, neutrophil, and lymphocyte and raised significantly (p ≤ 0.01) the wound contracture, hydroxyl proline, hexosamine, hexuronic acid, fibrocyte, and fibrocytes/fibroblast rate compared to other groups in experimental animals. In conclusion, synthesized MnNPs@ZC indicated antibacterial, antifungal, non-cytotoxicity, antioxidant, and cutaneous wound healing effects in a dose-depended manner. After confirming in the clinical trials, these nanoparticles can be used in human for the treatment of cutaneous and infectious diseases. 相似文献
10.
Recently, metallic nanoparticles have been used for the treatment of several disorders, such as cancer. Indeed, finding the chemotherapeutic drug of nanoparticles is in researching the priority of both developed and developing countries. The present study confirms the ability of aqueous extract of Thymus vulgaris grown under in vitro condition for the biosynthesis of gold nanoparticles (AuNPs). Also, in this study, we indicated the antioxidant, cytotoxicity, and anti-acute myeloid leukemia properties of AuNPs compared to doxorubicin in a leukemic mouse model. The synthesized AuNPs were characterized using different techniques including X-ray diffraction (XRD), energy Dispersive X-ray Spectrometry (EDS), fourier-transform infrared spectroscopy (FT-IR) spectroscopy, ultraviolet–visible spectroscopy (UV–Vis.), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenz[a]anthracene (DMBA) in 75 mice. Then, the animals were randomly divided into six subgroups, including control, untreated, doxorubicin, AuNPs, T. vulgaris, and HAuCl4. By quantitative real-time PCR, sphingosine-1-phosphate receptor-1 and sphingosine-1-phosphate receptor-5 mRNA expression in lymphocytes were significantly (P ≤ 0.01) raised by treating the leukemic mice with the AuNPs and doxorubicin. Also, AuNPs similar to doxorubicin, significantly (P ≤ 0.01) enhanced the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFNα) and the platelet, lymphocyte, and red blood cell (RBC) parameters and reduced the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNFα), and the total white blood cell (WBC), blast, monocyte, neutrophil, eosinophil, and basophil counts as compared to the untreated mice. In vitro design, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test revealed similar antioxidant potentials for doxorubicin and AuNPs. Furthermore, AuNPs similar to doxorubicin had low cell viability dose-dependently against 32D-FLT3-ITD, Human HL-60/vcr, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Above results confirm the excellent antioxidant, cytotoxicity, and anti-acute myeloid leukemia effects of AuNPs compared to doxorubicin. After confirming these results in clinical trial studies, AuNPs can be used as a chemotherapeutic drug for the treatment of acute myeloid leukemia in human. 相似文献