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排序方式: 共有175条查询结果,搜索用时 15 毫秒
1.
Elnaz Marzi Khosrowshahi Behnaz Limuie Khosrowshahi Mir Ali Farajzadeh Abolghasem Jouyban Mustafa Tuzen Mohammad Reza Afshar Mogaddam Mahboob Nemati 《Biomedical chromatography : BMC》2022,36(7):e5371
A dispersive solid-phase extraction method based on a new sorbent has been performed on plasma and wastewater samples to determine metoprolol by high-performance liquid chromatography–tandem mass spectrometry. In this study, the analyte was adsorbed from the samples onto microcrystalline cellulose as a green and efficient sorbent and then eluted for use in the determination step. In the mass spectrometer, the analyte was detected in the positive mode and selectivity of the analysis was increased by sequential mass analysis through multiple reaction monitoring. All of the effective parameters in the extraction of metoprolol from plasma and wastewater were optimized. Under optimal conditions the method was linear in the ranges of 1–1,000 and 0.1–1,000 ng/ml in plasma and wastewater samples, respectively. The detection limits of the method were 0.30 and 0.03 ng/ml in plasma and wastewater samples, respectively. The data showed that the method provides low detection limit, wide linear range, good precision and high extraction recovery. Finally several plasma and wastewater samples were successfully analyzed using the method. The use of a small amount of a green and inexpensive sorbent and a low volume of plasma without the need for further pretreatment steps are the main advantages of the method. 相似文献
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Behnaz Ghaffari Jorge Mendes-Burak Ka Wing Chan Prof. Dr. Christophe Copéret 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(61):13869-13873
Manganese, the third most abundant transition-metal element after iron and titanium, has recently been demonstrated to be an effective homogeneous catalyst in numerous reactions. Herein, the preparation of silica-supported MnII sites is reported using Surface Organometallic Chemistry (SOMC), combined with tailored thermolytic molecular precursors approach based on Mn2[OSi(OtBu)3]4 and Mn{N(SiMe3)2}2⋅THF. These supported MnII sites, free of organic ligands, efficiently catalyze numerous reactions: hydroboration and hydrosilylation of ketones and aldehydes as well as the transesterification of industrially relevant substrates. 相似文献
4.
Khaligh Nader Ghaffari Gorjian Hayedeh Fahim Hoda Titinchi Salam J. J. 《Research on Chemical Intermediates》2021,47(9):3529-3536
Research on Chemical Intermediates - An efficient solid/slurry-state synthesis of arylidene and alkylidene malonates as versatile intermediates is developed in the presence of mesoporous... 相似文献
5.
Electrical stimulation (ES) within a conductive scaffold is potentially beneficial in encouraging the differentiation of stem cells toward a neuronal phenotype. To improve stem cell-based regenerative therapies, it is essential to use electroconductive scaffolds with appropriate stiffnesses to regulate the amount and location of ES delivery. Herein, biodegradable electroconductive substrates with different stiffnesses are fabricated from chitosan-grafted-polyaniline (CS-g-PANI) copolymers. Human mesenchymal stem cells (hMSCs) cultured on soft conductive scaffolds show a morphological change with significant filopodial elongation after electrically stimulated culture along with upregulation of neuronal markers and downregulation of glial markers. Compared to stiff conductive scaffolds and non-conductive CS scaffolds, soft conductive CS-g-PANI scaffolds promote increased expression of microtubule-associated protein 2 (MAP2) and neurofilament heavy chain (NF-H) after application of ES. At the same time, there is a decrease in the expression of the glial markers glial fibrillary acidic protein (GFAP) and vimentin after ES. Furthermore, the elevation of intracellular calcium [Ca2+] during spontaneous, cell-generated Ca2+ transients further suggests that electric field stimulation of hMSCs cultured on conductive substrates can promote a neural-like phenotype. The findings suggest that the combination of the soft conductive CS-g-PANI substrate and ES is a promising new tool for enhancing neuronal tissue engineering outcomes. 相似文献
6.
Behnaz Afzalian Joel T. Mague Maryam Mohamadi S. Yousef Ebrahimipour Behjat Pour amiri Esmat Tavakolinejad Kermani 《催化学报》2015,(7):1101-1108
Three complexes containing 2-pyrazinecarboxylate (pzca–), including [Ni(pzca)2(H2O)2], [Co(pzca)2(H2O)2], and [Cu(pzca)2(H2O)2], have been synthesized and characterized using physico-chemical and spectroscopic methods. Furthermore, the structure of each complex was determined by single-crystal X-ray diffraction. All three complexes have an octahedral geometry, where the metal ion chelated by two carboxylate oxygens, two nitrogen atoms belonging to pyrazinic acid molecules, and two oxygen atoms of two water molecules. The catalytic activities of these complex-es were also investigated in the green synthesis of 2H-indazolo[2,1-b]phthalazine-triones by the reaction of hydrazine hydrate with an arylaldehyde, phthalic anhydride, and dimedone in acetic acid. 相似文献
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Thin nanocrystalline amorphous NiTi film was deposited on Si substrate using DC magnetron sputtering. The as-deposited NiTi thin film was crystallized by heat treatment at 500 °C for 1 h. The crystal structure, surface morphology, microstructure and surface chemistry of the deposited films were studied using X-ray diffraction, atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy (XPS), respectively. Corrosion behaviour was assessed in Ringer’s solution at 37 °C by open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy as a function of exposure time. OCP values indicate that the tendency for the formation of a spontaneous oxide film is greater for the NiTi thin films than the bulk NiTi. Long time exposure to Ringer’s solution was found to have a great effect on the corrosion behaviour of the samples. Significantly low corrosion current density was obtained for the annealed NiTi film from the potentiodynamic polarization curves indicating a typical passive behaviour, but as-deposited film and bulk NiTi alloy exhibited breakdown of passivity at potentials approximately +1.4 V (vs. SCE). XPS showed that the oxide film formed on the annealed NiTi thin film mainly composed of Ti oxides, and no evidence of Ni was found up to 8.2 nm beneath the top surface, suggesting the excellent corrosion resistance of this sample in Ringer’s solution. 相似文献
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Nader Ghaffari Khaligh 《催化学报》2014,(3)
Poly(4-vinylpyridinium) perchlorate has been used as a supported,recyclable,environmentally-benign catalyst for the formation of acylals from aliphatic and aromatic aldehydes in good to excellent yields under solvent-free conditions.Notably,the reaction conditions were tolerant of ketones.This methodology offers several distinct advantages,including its operational simplicity and high product yield,as well as being green in terms of avoiding the use of toxic catalysts and solvents.Furthermore,the catalyst can be recovered and reused several times without any loss in its activity. 相似文献
10.
A novel heterogeneous magnetic palladium nano‐biocatalyst was designed by utilizing Irish moss, a family of sulfated polysaccharides extracted from algae, as a natural biopolymer. This magnetic Irish moss decorated with palladium (Pd–Fe3O4@IM) to form a biomagnetic catalytic system was synthesized and well characterized by FT–IR analysis, X‐ray powder diffraction, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, atomic absorption spectroscopy and transmission electron microscopy. The catalyst was stable to air and moisture and displayed high catalytic activity in ligand‐free Suzuki–Miyaura cross‐coupling reactions conducted under green chemistry reaction conditions. The aromatic ketones are produced by the cross‐coupling reaction between acid chlorides and aryl boronic acid derivatives in high yields. 相似文献