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41.
Samadi N Manayi A Vazirian M Samadi M Zeinalzadeh Z Saghari Z Abadian N Mozaffarian VO Khanavi M 《Natural product research》2012,26(20):1931-1934
The essential oil obtained from the flowering parts of Anthemis altissima L. var. altissima was analysed by gas chromatography and gas chromatography mass spectroscopy. In this study, 34 compounds representing 98.76% of the essential oil were identified. The main components were α-terpineol (26.42%), β-pinene (9.23%), cis-chrysanthenyl acetate (6.30%), globulol (5.36%), n-tricosane (4.41%), terpinen-4-ol (4.08%) and 1,8 cineole (3.84%). Antibacterial activities of the essential oil and its two major components (α-terpineol and β-pinene) were determined using microdilution method against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria. The essential oil showed a broad-spectrum antibacterial activity (MICs ranged from 3.13 to 6.25?μL?mL(-1)). It was found that α-terpineol with minimum inhibitory concentration (MIC) values of the range 0.87-1.56?μL?mL(-1) was a more potent antibacterial agent than β-pinene with MIC values of the range 1.56-6.25?μL?mL(-1). All of them, the essential oil, β-pinene and α-terpineol, were more effective against Gram-positive bacteria than Gram-negative ones. 相似文献
42.
Mahnaz M.Abdi H.N.M.Ekramul Mahmud Luqman Chuah Abdullah Anuar Kassim Mohamad Zaki Ab.Rahman Josephine Liew Ying Chyi 《高分子科学》2012,(1):93-100
Electrical conductivity and optical properties of polypyrrole-chitosan(PPy-CHI) conducting polymer composites have been investigated to determine the optical transition characteristics and energy band gap of composite films.The two electrode method and I-V characteristic technique were used to measure the conductivity of the PPy-CHI thin films,and the optical band gap was obtained from their ultraviolet absorption edges.Depending upon experimental parameter,the optical band gap(Eg) was found within 1.30-2.32 eV as estimated from optical absorption data.The band gap of the composite films decreased as the CHI content increased.The room temperature electrical conductivity of PPy-CHI thin films was found in the range of 5.84×10-7-15.25×10-7 S·cm-1 depending on the chitosan content.The thermogravimetry analysis(TGA) showed that the CHI can improve the thermal stability of PPy-CHI composite films. 相似文献
43.
Hollow fiber liquid-phase microextraction (HF-LPME) offers an efficient alternative to classical techniques for sample preparation and preconcentration. Features include high selectivity, good enrichment factors, and improved possibilities for automation. HP-LPME relies on the extraction of target analytes from aqueous samples into a supported liquid membrane (SLM) sustained in the pores of the wall of a porous hollow fiber, and then into an acceptor phase (that can be aqueous or organic) in the lumen of the hollow fiber. After extraction, the acceptor solution is directly subjected to a chemical analysis. HP-LPME can be performed in either the 2- or 3-phases mode. In the 2-phase mode, the organic solvent is present both in the porous wall and inside the lumen of the hollow fiber. In the 3-phase mode, the acceptor phase can be aqueous and this results in a conventional 3-phase system compatible with HPLC or capillary electrophoresis. Alternatively, the acceptor solution is organic and this represents a 3-phase extraction system with two immiscible organic solvents that is compatible with all common analytical instruments. In HP-LPME methods based on the use of SLMs, the mass transfer occurs by passive diffusion, and high extraction yields as well as efficient extraction kinetics are obtained by applying a pH gradient. In addition, active transport can be performed by using carrier or applying an electrical potential across the SLM. Due to high analyte preconcentration, excellent sample clean-up, and low consumption of organic solvent, HF-LPME has a large application potential in areas such as drug analysis and environmental monitoring. This review focuses on the fundamentals of extraction principles, technical implementations, and future trends in HF-LPME. Figure
Schematic diagram of three-phase HF-LPME based of two immiscible organic solvent 相似文献
44.
Masoud Salavati-Niasari Mahnaz Dadkhah Mohammad Reza Nourani Alireza Amini Fazl 《Journal of Cluster Science》2012,23(4):1011-1017
A simple thermal decomposition route has been developed to prepare single-phase cubic ZrO2 nanospheres by [Zr(sal)3(H2O)2](NO3) as the new precursor. The ZrO2 nanocrystals have been prepared by bis-aqua, tris-salicylaldehydato zirconium(IV) nitrate; [Zr(sal)3(H2O)2](NO3), as precursor in oleylamine (C18H37N) and triphenylphosphine (C18H15P). To control the particle size, combination of C18H37N and C18H15P were applied as surfactants. The C18H37N and C18H15P play an important role in preventing aggregation of ZrO2 nanocrystals. The products were characterized by X-ray diffraction, transmission electron microscopy, photoluminescence spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy to depict the phase and morphology. The FT-IR spectrum showed the purity of obtained ZrO2 nanocrystals with cubic phase. 相似文献
45.
Hedayati Nafiseh Montazer Majid Mahmoudirad Mahnaz Toliyat Tayebeh 《Cellulose (London, England)》2021,28(12):8095-8113
Cellulose - The influence of ketoconazole and β-CD/ketoconazole on cotton fabric as fungal skincare was previously reported however the impact of nanosilver on the antifungal and antibacterial... 相似文献
46.
Mahnaz?Nozohour Yazdi Yadollah?YaminiEmail author Hamid?Asiabi Abdolali?Alizadeh 《Mikrochimica acta》2018,185(11):525
Novel composites were obtained via direct assembly of polysulfides (Sx2?, X?=?3, 4, 6) on the surface of a metal organic framework (MOF; type benzene-1,3,5-tricarboxylic/Cu(II). They are referred to as Sx-MOFs and were used for highly selective and efficient extraction of ultra-trace amounts of heavy metal ions from aqueous solutions. The structure of the Sx-MOFs was characterized by Raman spectroscopy, FT-IR, X-ray diffraction, and scanning electron microscopy. The Raman spectra of Sx-MOF is similar to the bare MOF and shows the MOFs structure to be well retained after Sx functionalization. The selective interaction of Sx with soft metal ions and the high surface area of MOFs resulted in excellent affinity and selectivity for ions such as Hg(II). The Sx-MOFs of type S4-MOF had the highest distribution coefficient Kd value (~107) and best extraction recovery (~100%) for Hg(II). The S4-MOF also has high selectivity in the following order: Hg(II) >?>?Pb(II)?>?Zn(II)?>?Ni(II)?>?Co(II). The binding process of the metals occurs via M–S bonding. The ions were quantified by inductively coupled plasma optical emission spectrometry (ICP-OES). The detection limit for Hg(II) is 0.13 μg L?1. The S4-MOF was applied to the extraction of trace metal ions from natural and contaminated waters and data were compared with other sorbets. The results revealed that S4-MOF is an excellent adsorbent for sorption of heavy metal ions even in the presence of the relatively high concentration of other ions. 相似文献
47.
Partitioning and assembly of metal particles and their bioconjugates in aqueous two-phase systems 总被引:1,自引:0,他引:1
Helfrich MR El-Kouedi M Etherton MR Keating CD 《Langmuir : the ACS journal of surfaces and colloids》2005,21(18):8478-8486
The behavior of metal nanospheres and nanowires and their bioconjugates in aqueous two-phase systems (ATPS) is described. The ATPS used in this work comprised poly(ethylene glycol) (PEG), dextran, and water or aqueous buffer. Au and Ag nanospheres less than 100 nm in diameter partition between the PEG-rich and dextran-rich phases on the basis of their surface chemistry and can be separated on this basis. Larger Au nanospheres and wires accumulate at the interface between the two aqueous phases. The influence of polymer molecular weight and concentration on interfacial assembly of Au wires is described. DNA-derivatized nanowires at the aqueous/aqueous interface retain the ability to selectively bind to fluorescent complementary DNA. In addition, Au nanoparticles have been bound to Au wires via selective DNA hybridization at the ATPS interface. Transmission electron microscopy and thermal denaturation experiments confirm that DNA-driven assembly is responsible for the formation of the nanosphere/wire assemblies. These results demonstrate the biocompatibility of the two-phase interface and point to future use as scaffolding in biorecognition-driven assembly. 相似文献
48.
Suzuki–Miyaura coupling catalyzed by palladium nanoparticles biosynthesized using Glycyrrhiza glabra as reducing and stabilyzing agent 下载免费PDF全文
Hojat Veisi Mehdi Adib Rahman Karimi‐Nami Zahra Yasaei Mahnaz Tajik Talieh Sadat Mosavat Saba Hemmati 《应用有机金属化学》2018,32(3)
An unprecedented environmentally friendly method has been developed for the synthesis of palladium nanoparticles supported on Glycyrrhiza glabra. The synthesized nanoparticles were utilized in Suzuki–Miyaura reaction between different aryl halides and aryl bronic acid in aqueous media. This heterogeneous catalyst can be reused and recycled repeatedly more than five times with only slight loss of its initial catalytic efficiency. This reaction carrid out under atmospheric pressure with high efficiency, unique and simple work‐up procedure and excellent yields. 相似文献
49.
Naderi Mahnaz Shamirian Armen Edrisi Mohammad 《Journal of Sol-Gel Science and Technology》2011,58(2):557-563
In the present work nano crystalline copper aluminate (CuAl2O4) has been synthesized by the Pechini method using aqueous solutions containing corresponding metal nitrates. A Taguchi L4 statistical design was employed for investigating the most effective factors on the synthesis conditions and their interactions
and production optimization. Nano crystalline CuAl2O4 particles with crystal size between 17 and 26 nm were obtained. The product characterized by XRD, FT-IR, DLS and TGA. The
morphological properties have investigated using SEM. The photocatalytic degradation was investigated using methyl orange
under the irradiation of visible light. 相似文献
50.
A novel and efficient method for the N-formylation of amines via the reaction of orthoformates and amines is developed. The reactions are mediated by a catalytic amount of molybdate sulfuric acid as a heterogeneous solid acid. 相似文献