排序方式: 共有159条查询结果,搜索用时 654 毫秒
31.
In this study, the application of various concentrations (0.02%, 0.04%, 0.06% and 0.08%) of Satureja khuzestanica essential oil (EO) was examined on the oxidative stability of sunflower oil and compared to butylated hydroxyanisole (BHA) during storage at 60°C. Gas chromatography (GC) and GC-mass spectrometry analyses of the oils revealed that carvacrol (87.7%) was the major component of EO. Peroxide value and anisidine value measurements in sunflower oil showed that all concentrations of EO had antioxidant effects in comparison to BHA. Oil samples supplemented with EO concentration of 0.08% were the most stable during storage (p?0.05). EO also was able to reduce the stable free radical 2, 2-diphenyl-1-picrylhydrazyl with a 50% inhibition concentration (IC??) of 31.5?±?0.6?μg?mL?1. Therefore, the results indicate that EO could be used as a natural antioxidant in food lipids. 相似文献
32.
Funian Zhao Ali Reza Mahdavian Mohammad Bagher Teimouri Eric S. Daniels Andrew Klein Mohamed S. El-Aasser 《Colloid and polymer science》2012,290(13):1247-1255
The preparation of poly(vinyl acetate) with well-controlled structure has received a great deal of interest in recent years because of a large number of developments in living radical polymerization techniques. Among these techniques, the use of reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization has been employed for the controlled polymerization of vinyl acetate due to the high susceptibility of this monomer towards chain transfer reactions. Here, a novel water-soluble N,N-dialkyl dithiocarbamate RAFT agent has been prepared and employed in the emulsion polymerization of vinyl acetate. The kinetic results reveal that the polymerization nucleation mechanism changes from homogeneous to micellar and RAFT-generated radicals can change the kinetic behavior from conventional emulsion polymerization to living radical polymerization. At higher concentrations of the modified RAFT agent, as a result of an aqueous phase reaction between RAFT and sulfate radicals, relatively more hydrophobic radicals are generated, which favors entry and propagation into micelles swollen with monomer. This observation was determined from the investigation of the polymerization rate and measurements of the average particle diameter and the number of particles per liter of the aqueous phase. Molecular weight analysis also demonstrated the participation of the RAFT agent in the polymerization in such a way as to restrict chain transfer reactions. This was determined by examining the evolution of polymer chain length and attaining higher molecular weights, even up to 50?% greater than the samples obtained from the conventional emulsion polymerization of vinyl acetate in the absence of the synthesized modified RAFT agent. 相似文献
33.
Mohammad Ali Ansari Saeid Alikhani Ezeddin Mohajerani Reza Massudi 《Optics Communications》2012,285(5):851-855
In this study, the diffusion of photons in turbid media, like biological tissue has been studied. Due to scattering and absorption of photons in such media, the study of photon propagation in biological tissue is complicated. The several numerical methods have been presented to simulate the behavior of diffused photons. Recently, Boundary Integral Method (BIM) has been offered to simulate photon migration inside biological tissues. This method has advantage, e.g. lower computational time in compared with other numerical methods. In this study, the accuracy and precision of BIM compares with another numerical method like Monte Carlo technique and finite difference method, and also the calculated results obtained by BIM and Monte Carlo method evaluate with measured results. Furthermore, the effects of scattering and absorption coefficient of tissue on the measured signal are studied. 相似文献
34.
Morteza Akhond Mohammad Bagher Najafi Javad Tashkhourian 《Analytica chimica acta》2005,531(2):179-184
In this study, a new poly(vinyl chloride) (PVC) membrane sensor for La3+ ion based on 2,2′-dithiodipyridine as an ion carrier was prepared. This electrode revealed good selectivity for La3+ over a wide variety of other metal ions. Effects of experimental parameters such as membrane composition, nature and amount of plasticizer, the amount of additive and concentration of internal solution on the potential response of La3+ sensor were investigated. The electrode exhibited a Nernstian slope of 20.0 ± 1.0 mV per decade of La3+ over a concentration range of 7.1 × 10−6 to 2.2 × 10−2 M of La3+ in the pH range 3.3-8.0. The response time was about 7 s and the detection limit was 3.1 × 10−6 M. The electrode can be used for at least 2 months without a considerable divergence in potential. The proposed electrode was used as an indicator electrode in potentiometric titration of oxalate and fluoride ions and was applied for determination of F− ion in mouthwash solution. 相似文献
35.
Mohammed M. Hashemi Bagher Eftekhari-Sis Amir Abdollahifar Behzad Khalili 《Tetrahedron》2006,62(4):672-677
At room temperature, ZrOCl2·8H2O on montmorillonite K10 efficiently catalyzes conjugate addition of amines to a variety of conjugated alkenes such as α,β-unsaturated carbonyl compounds, carboxylic esters, nitriles and amides under solvent-free conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency. 相似文献
36.
Farhood Bagher Geraily Ghazale Abtahi Seyed Mohammad Mahdi Ghorbani Mahdi Mehdikhani Mohamad 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(2):1041-1050
Journal of Radioanalytical and Nuclear Chemistry - In the current study, dose rate and photon energy dependence of PASSAG gel dosimeter is evaluated by using MRI technique. The gel samples were... 相似文献
37.
Bagher Mohajerani Majid M. Heravi Dariush Ajami 《Monatshefte für Chemie / Chemical Monthly》2001,132(7):871-873
Summary. Primary and secondary tetrahydropyranyl ethers are efficiently converted to carbonyl compounds in excellent yields by zeofen
under non-aqueous conditions.
Received November 21, 2000. Accepted (revised) January 9, 2001 相似文献
38.
Mohammad S. Asgari Behnam Tahmasebi Somayeh Mojtabavi Mohammad A. Faramarzi Rahmatollah Rahimi Parviz R. Ranjbar Mahmood Biglar Bagher Larijani Hossein Rastegar Maryam Mohammadi-Khanaposhtani Mohammad Mahdavi 《Journal of heterocyclic chemistry》2020,57(12):4348-4357
A new series of acridine-9-carboxamide-1,2,3-triazole derivatives 7a-m were designed, synthesized, and evaluated as novel α-glucosidase inhibitors. Acridine-9-carboxamide-1,2,3-triazole scaffold has been designed by combination of effective moieties from potent α-glucosidase inhibitors. Most of the synthesized compounds were more potent than standard inhibitor acarbose. Among the title compounds, the most potent compounds were compounds 7j , 7k , and 7a with IC50 values of 120.2 ± 1.0, 151.1 ± 1.4, and 157.6 ± 1.6 μM, respectively (IC50 value of acarbose = 750.0 ± 10.0 μM). Docking study of the most potent compounds demonstrated that these compounds formed stable complexes with α-glucosidase active site. Anti-α-amylase assay of compounds 7j , 7k , and 7a was performed and no activity was observed. in vitro cytotoxicity assay of the latter compounds revealed that these compounds were not cytotoxic toward human normal (HDF) and cancer (MCF-7) cell lines. ADME and toxicity prediction of compounds 7j , 7k , and 7a were also performed. 相似文献
39.
In this work, we have been investigating an organic tandem solar cells composed of PF10TBT:PCBM by using optical modeling and simulation method to investigate the correlation between thickness and photocurrent. Possible thickness pairs of tandem cell are provided when front layer and back layer absorb same amount of photons. In order to obtain the possible thickness pairs for different wavelengths, photocurrent has been simulated as function of back and front layer thickness. Energy dissipation in term of distance along cell and wavelengths were analyzed to interpret the optimal geometry of tandem cell. In order to find the appropriate materials for maximum efficiency, energy dissipation as function of optical constant (n) and wavelengths were simulated to derive the optimal condition. 相似文献
40.
A three-component domino reaction approach between a primary amine, a dialkyl acetylenedicarboxylate, and 1,3-dimethylalloxan that affords novel oxaspirobicyclic γ-butenolidobarbiturate derivatives is reported. The reaction sequence consists of an initial Michael-addition of primary amines to dialkyl acetylenedicarboxylates, followed by aldol-like reaction with 1,3-dimethylalloxan, and then γ-lactonization to afford the products. This cascade reaction sequence represents a rapid and unprecedented route to the described biologically interesting molecules. 相似文献