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81.
Soleyman Hosseinzadeh Younes Saadat Hormoz Eslami Faramarz Afshar-Taromi Alireza Hosseinzadeh Mehdi Rimaz Vahid Hooshangi 《Colloid and polymer science》2012,290(16):1713-1719
In this work, the preparation of micron-sized polymer particles with nonspherical shapes via seeded dispersion polymerization of 2-ethylhexyl methacrylate with polystyrene seed particles in the presence of hydrocarbon droplets and evaporation of hydrocarbon after the polymerization under various polymerization conditions was discussed. The effect of second monomer and initiator type, mixing method, and stabilizer content on the shape of the obtained particles was investigated. It was observed that particles with more nonspherical shapes were obtained with increasing the alkyl chain length of ester group of the methacrylate of the second monomer which is because of increasing the absorption amounts of hydrocarbon by second polymer domains. Moreover, the experimental results showed that shape of the particles which was produced by shaking is more nonspherical than the shape of the particles which was obtained from tumbling. Furthermore, particles with different nonspherical shapes were prepared by changing the initiator type and stabilizer content. 相似文献
82.
Nanoparticles of a three-dimensional supramolecular, [Cu(L)2(H2O)2] (1), (L− = 1H-1,2,4-triazole-3-carboxylate), have been synthesized by a sonochemical process and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. The thermal stability of compound 1 both its bulk and nano-size has been studied by thermal gravimetric (TG) and differential thermal analyses (DTA) and compared each other. Concentration of initial reagents effects on size and morphology of nano-structured compound 1, have been studied. Calcination of the nano-sized compound 1 at 600 °C under air atmosphere yields CuO nanoparticles. 相似文献
83.
In this research high-quality zinc oxide (ZnO) nanowires have been synthesized by thermal oxidation of metallic Zn thin films. Metallic Zn films with thicknesses of 250 nm have been deposited on a glass substrate by the PVD technique. The deposited zinc thin films were oxidized in air at various temperatures ranging between 450 °C to 650 °C. Surface morphology, structural and optical properties of the ZnO nanowires were examined by scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and photoluminescence (PL) measurements. XRD analysis demonstrated that the ZnO nanowires has a wurtzite structure with orientation of (002), and the nanowires prepared at 600 °C has a better crystalline quality than samples prepared at other temperatures. SEM results indicate that by increasing the oxidation temperature, the dimensions of the ZnO nanowires increase. The optimum temperature for synthesizing high density, ZnO nanowires was determined to be 600 °C. EDX results revealed that only Zn and O are present in the samples, indicating a pure ZnO composition. The PL spectra of as-synthesized nanowires exhibited a strong UV emission and a relatively weak green emission. 相似文献
84.
Bahram Ghalami-Choobar Vahid Mahdavi Shadfar Pourpanah 《Journal of solution chemistry》2012,41(1):89-99
In this work mean activity coefficient measurements for KCl in the KCl + formamide + water system, using the potentiometric
method, are reported. The electromotive force measurements were performed on a galvanic cell of the type Ag | AgCl | KCl (m), formamide (w%), H2O (1−w)% | K-ISE, in solvent mixtures containing w=(0,10,20,30, and 40)% mass percent of formamide over ionic strengths ranging from 0.0010 to 3.9578 mol⋅kg−1. Modeling of the activity coefficients of this ternary system was based on an extended Debye–Hückel equation and the Pitzer
ion-interaction model. The resulting values of the mean activity coefficients, the osmotic coefficients and the excess Gibbs
energy, together with Pitzer ion-interaction parameters (β
(0), β
(1) and C
ϕ
) and Debye–Hückel parameters (a, c and d), are reported for the investigated system. 相似文献
85.
Chemical speciation (extraction of elemental information and identification of molecular environment for an analyte in a complex sample) has been a long sought after goal for analytical chemists. Recently, because of successful developments in more sensitive element-specific detectors and gentle separation schemes, which preserve the true chemical information in a real sample, routine speciation experiments are becoming a common occurrence in the scientific literature. For many reasons, the combination of capillary electrophoresis (for separation of different chemical species) with inductively coupled plasma mass spectrometry (for element and isotope specific detection) has emerged as the method of choice for these analyses. In this article the basic principles of capillary electrophoresis inductively coupled plasma mass spectrometry are discussed. Design consideration for instrument interface, anticipated difficulties with speciation experiments and applications for specific matrices and analytes are also presented in this article. 相似文献
86.
Marie-Pierre Girard Vahid Karimzadegan Marianne Hneault Francis Cloutier Gervais Brub Lionel Berthoux Natacha Mrindol Isabel Desgagn-Penix 《Molecules (Basel, Switzerland)》2022,27(17)
Amaryllidaceae alkaloids (AAs) are a structurally diverse family of alkaloids recognized for their many therapeutic properties, such as antiviral, anti-cholinesterase, and anticancer properties. Norbelladine and its derivatives, whose biological properties are poorly studied, are key intermediates required for the biosynthesis of all ~650 reported AAs. To gain insight into their therapeutic potential, we synthesized a series of O-methylated norbelladine-type alkaloids and evaluated their cytotoxic effects on two types of cancer cell lines, their antiviral effects against the dengue virus (DENV) and the human immunodeficiency virus 1 (HIV-1), and their anti-Alzheimer’s disease (anti-cholinesterase and -prolyl oligopeptidase) properties. In monocytic leukemia cells, norcraugsodine was highly cytotoxic (CC50 = 27.0 μM), while norbelladine was the most cytotoxic to hepatocarcinoma cells (CC50 = 72.6 μM). HIV-1 infection was impaired only at cytotoxic concentrations of the compounds. The 3,4-dihydroxybenzaldehyde (selectivity index (SI) = 7.2), 3′,4′-O-dimethylnorbelladine (SI = 4.8), 4′-O-methylnorbelladine (SI > 4.9), 3′-O-methylnorbelladine (SI > 4.5), and norcraugsodine (SI = 3.2) reduced the number of DENV-infected cells with EC50 values ranging from 24.1 to 44.9 μM. The O-methylation of norcraugsodine abolished its anti-DENV potential. Norbelladine and its O-methylated forms also displayed butyrylcholinesterase-inhibition properties (IC50 values ranging from 26.1 to 91.6 μM). Altogether, the results provided hints of the structure–activity relationship of norbelladine-type alkaloids, which is important knowledge for the development of new inhibitors of DENV and butyrylcholinesterase. 相似文献
87.
Rezaei Shokoofe Rahpeima Soraya Esmaili Javad Javanbakht Vahid 《Russian Journal of Applied Chemistry》2021,94(4):533-548
Russian Journal of Applied Chemistry - Magnetic nanoparticles and clay minerals combine to form a class of advanced nanocomposites that would possess exceptional adsorption, magnetism, and... 相似文献
88.
Masoud Homayouni-Tabrizi Ehsan Karimi Farideh Namvar Mozhgan Soltani Vahid Pouresmaeil 《Research on Chemical Intermediates》2018,44(11):6537-6548
The aim of the present study is to evaluate the antioxidant and proapoptotic effects of silver–palm pollen (Ag/PP) nanocomposite. The percentage of live cells after treatment with various concentrations of Ag/PP (0, 5, 10, 20, and 40 µM/mL) was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The antioxidant potential of Ag/PP was measured via the scavenging effects of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and molecular analysis. Apoptosis was assessed by morphological analysis, fluorescent dye, and flow cytometry, and its fundamental mechanism studied based on evaluation of Bax and Bcl2 gene expression. Ag/PP nanocomposite suppressed the viability of MCF-7 cells (dose and time dependently) and showed antioxidant properties. Morphological changes associated with cell death were observed in treated cells. Accumulation of dead cells in sub-G1 phase confirmed the occurrence of apoptosis in exposed cells. In addition, NPs induced cell death by altering Bcl-2 expression in MCF-7 cells. These results indicate that Ag/PP nanocomposite is an effective combination for removal of cancer cells by induction of apoptosis and could be useful for human health due to its antioxidant effects. 相似文献
89.
The reaction of solution 2,6‐pyridinedicarboxylic acid ( 1 ) and 2,2′‐Bipyridine with Pb(NO3)2 led to the coordination polymer [Pb(pydc)]n ( 2 ) (pydcH2 is 2,6‐pyridinedicarboxylic acid). This complex was characterized by elemental analysis, IR spectroscopy and single‐crystal structure of 2 . Crystal data for 2 at ?80 °C: monoclinic, space group P21/n, a = 977.2(1), b = 554.0(1), c = 1425.3(2) pm, β = 104.75(1)°, Z = 4, R1= 0.0261. The units [Pb(pydc)] form infinite chains along [010]. 相似文献
90.
Pt(II) complexes immobilized on polymer‐modified magnetic carbon nanotubes as a new platinum drug delivery system 下载免费PDF全文
Seyed Jamal Tabatabaei Rezaei Ali Hesami Hossein Khorramabadi Vahid Amani Asemeh Mashhadi Malekzadeh Ali Ramazani Hassan Niknejad 《应用有机金属化学》2018,32(7)
We combine nanotechnology and chemical synthesis to create a novel multifunctional platinum drug delivery vehicle based on magnetic carbon nanotubes (multiwall carbon nanotubes/Fe3O4@poly(citric acid)/cis‐[(Pt(1,7‐phenanthroline)(DMSO)Cl2)]‐b‐poly(ethylene glycol) (MCNTs/FO@PC/Pt(II)‐b‐PEG)) for targeted cancer therapy. MCNTs/FO@PC/Pt(II)‐b‐PEG was conveniently prepared by conjugating cis‐[Pt(1,7‐phenanthroline)(DMSO)Cl2] complex to MCNTs/FO@PC‐b‐PEG via strong hydrogen‐bonding interactions. In comparison with free cisplatin and Pt(II) complex, MCNTs/FO@PC/Pt(II)‐b‐PEG shows higher solubility in aqueous solution and higher cytotoxicity towards human cervical cancer HeLa cells and human breast cancer MDA‐MB‐231 cells. In vitro release experiments revealed that the platinum drug‐loaded delivery system is relatively stable under physiological conditions (pH = 7.4 and 37 °C) but susceptible to acidic environments (pH = 5.6 and 37 °C) which would trigger the release of loaded drugs. Fluorescence microscopy studies revealed that this magnetic nanohybrid system possesses marked cell‐specific targeting in vitro in the presence of an external magnetic field. The results indicated that the prepared superparamagnetic MCNTs/FO@PC/Pt(II)‐b‐PEG nanohybrid system is a promising candidate for inhibiting the proliferation of cancer cells. 相似文献