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排序方式: 共有562条查询结果,搜索用时 546 毫秒
31.
Sajedi Mohammad Mansoori Yagoub Nuri Ayat Fekri Somayeh Esquivel Dolores Navarro M Angeles 《Catalysis Surveys from Asia》2022,26(3):193-210
Catalysis Surveys from Asia - 2-(2-Pyridyl)benzimidazole (PyBzIm) was supported onto magnetic mesoporous silica, Fe3O4@SiO2@SBA-15 via the click chemistry. The supported ligand was treated with... 相似文献
32.
Mohammad A. Alzohairy Amjad Ali Khan Mohammed A. Alsahli Saleh A. Almatroodi Arshad Husain Rahmani 《Molecules (Basel, Switzerland)》2021,26(11)
Benzopyrene [B(a)P] is a well-recognized environmental carcinogen, which promotes oxidative stress, inflammation, and other metabolic complications. In the current study, the therapeutic effects of thymoquinone (TQ) against B(a)P-induced lung injury in experimental rats were examined. B(a)P used at 50 mg/kg b.w. induced lung injury that was investigated via the evaluation of lipid profile, inflammatory markers, nitric oxide (NO), and malondialdehyde (MDA) levels. B(a)P also led to a decrease in superoxide dismutase (SOD) (34.3 vs. 58.5 U/mg protein), glutathione peroxidase (GPx) (42.4 vs. 72.8 U/mg protein), catalase (CAT) (21.2 vs. 30.5 U/mg protein), and total antioxidant capacity compared to normal animals. Treatment with TQ, used at 50 mg/kg b.w., led to a significant reduction in triglycerides (TG) (196.2 vs. 233.7 mg/dL), total cholesterol (TC) (107.2 vs. 129.3 mg/dL), and inflammatory markers and increased the antioxidant enzyme level in comparison with the group that was administered B(a)P only (p < 0.05). B(a)P administration led to the thickening of lung epithelium, increased inflammatory cell infiltration, damaged lung tissue architecture, and led to accumulation of collagen fibres as studied through haematoxylin and eosin (H&E), Sirius red, and Masson’s trichrome staining. Moreover, the recognition of apoptotic nuclei and expression pattern of NF-κB were evaluated through the TUNEL assay and immunohistochemistry, respectively. The histopathological changes were found to be considerably low in the TQ-treated animal group. The TUNEL-positive cells increased significantly in the B(a)P-induced group, whereas the TQ-treated group showed a decreased apoptosis rate. Significantly high cytoplasmic expression of NF-κB in the B(a)P-induced group was seen, and this expression was prominently reduced in the TQ-treated group. Our results suggest that TQ can be used in the protection against benzopyrene-caused lung injury. 相似文献
33.
Mustafa Aghazadeh Mehdi Ghaemi Behrouz Sabour Somayeh Dalvand 《Journal of Solid State Electrochemistry》2014,18(6):1569-1584
Well-dispersed nanoparticles of nickel hydroxide were prepared via a simple electrochemical method. Electrodeposition experiments were performed from 0.005 M Ni(NO3)2 bath at a constant current density of 0.1 mA cm?2 on the steel cathode for 1 h. Recording the potential values during the deposition process revealed that the reduction of water has major role in the base electrogeneration at the applied conditions. The obtained deposit was characterized by the X-ray diffraction (XRD), infrared (IR), differential scanning calorimeter–thermogravimetric analysis, carbon–nitrogen–hydrogen (CHN), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The CHN, XRD, and IR analyses showed that the obtained deposit has α phase of Ni(OH)2 with intercalated nitrate ions in its structure. Morphological characterization by SEM and TEM revealed that the prepared α-Ni(OH)2 is composed of well-dispersed ultrafine particles with the size of about 5 nm. The supercapacitive performance of the prepared nanoparticles was analyzed by means of cyclic voltammetry and galvanostatic charge–discharge tests. The electrochemical measurements showed an excellent supercapacitive behavior of the prepared α-Ni(OH)2 nanoparticles. It was also observed that the α-Ni(OH)2 ultrafine particles have better electrochemical characteristic and supercapacitive behavior than β-Ni(OH)2 ultrafine nanoparticles, including less positive charging potential, lower E a???E c value, better reversibility, higher E OER???E a, higher utilization of active material, higher proton diffusion coefficient, greater discharge capacity, and better cyclability. These results make the α-Ni(OH)2 nanoparticles as an excellent candidate for the supercapacitor materials. 相似文献
34.
Pooria Varahram Somayeh Mohammady Borhanuddin Mohd Ali 《Wireless Personal Communications》2013,72(2):1125-1137
Peak-to-average power ratio (PAPR) is one of the main drawbacks in orthogonal frequency division multiplexing (OFDM) systems. High PAPR forces the power amplifier to back off in order to operate in its linear region, which degrades the power efficiency of the system. Several PAPR reduction techniques have been developed, but most of them have not considered both complexity and PAPR reduction. In this paper, a novel PAPR reduction scheme based on the insertion of dummy sequences to an enhanced partial transmit sequence is proposed. By applying this scheme the PAPR performance is enhanced compared to the conventional methods while the complexity is significantly reduced. Numerical analysis is carried out with OFDM signal and QPSK modulation. 相似文献
35.
36.
Our recent studies on the stem bark of Calophyllum mucigerum (Guttiferae) have yielded a new coumarin mucigerin, a prenylated xanthone cudraxanthone C and the common steroidal triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved using 1H NMR, 13C NMR, DEPT, COSY, HETCOR and HMBC experiments while MS gave the molecular masses. Cytotoxic assays using CEM-SS cell line (T-lymphoblastic leukemia) on the crude extracts of the stem bark indicated some activity. The crude extracts were also found to be moderately toxic against the larvae of Aedes aegypti. This article reports the isolation and identification of mucigerin as well as bioassay data. 相似文献
37.
KF‐Melamine formaldehyde resin (KF‐MFR) was demonstrated to be a highly efficient heterogenious catalyst for cross‐aldol condensation under microwave irradiation. In this synthesis, various aldehydes and ketones were condensed together in the presence of supported KF on melamine‐formaldehyde resin to afford different chalcone derivatives in good to excellent yields. KF‐MFR proved to have unique termal and chemical resistance and can be reused for many consecutive runs without remarkable loss in catalytic activity. 相似文献
38.
Liliane Bokobza Mostafa Rahmani Colette Belin Jean‐Luc Bruneel Nour‐Eddine El Bounia 《Journal of Polymer Science.Polymer Physics》2008,46(18):1939-1951
The reinforcement of a styrene‐butadiene rubber (SBR) by single fillers—carbon black (CB) or multiwall carbon nanotubes (MWNTs)—or by mixtures of CB and MWNTs, is investigated. The morphologies, mechanical and electrical properties of the composites, are analyzed. A significant improvement in the tensile properties is observed for samples containing a dual phase. Using atomic force (AFM) and transmission electron (TEM) microscopies, we demonstrate that the double loading improves the dispersion of the nanotubes in SBR. Electrical measurements show lower resistivity and a lower percolation threshhold for composites containing blends of fillers, which provides further evidence of better dispersion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 46: 1939–1951, 2008 相似文献
39.
Rezaee Elham Amrolah Somayeh Minaei Nazari Maryam Tabatabai Sayyed Abbas 《Molecular diversity》2021,25(1):45-53
Molecular Diversity - Soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators, epoxyeicosatrienoic acids, which are involved in the... 相似文献
40.
Mashaallah Rahmani Massoud Kaykhaii Zahra Safari Ommolbanin Ansari Shahrzad Jaberi Nasab 《Chromatographia》2017,80(1):109-117
Three new dispersive liquid–liquid microextraction (DLLME) methods, air-assisted (AA-DLLME), vortex-assisted (VA-DLLME) and ultrasound-assisted (UA-DLLME), were compared from the point of view of their analytical application for preconcentration of trace amounts of benzene, toluene, ethylbenzene and xylene isomers (BTEX) in water samples. In all of these methods, no dispersive solvent is required and dispersion of extractant is carried out by air bubbles, vortex and ultrasound for AA-DLLEM, VA-DLLME, and UA-DLLME, respectively. Advantages and disadvantages of these three liquid phase microextraction methods and their capability in dispersion of a similar extractant phase in sample solutions were comprehensively compared. All other extraction parameters, which have an influence on the microextraction, were also investigated and optimized. Under optimized conditions, analytical figures of merit for the three techniques were determined and compared. It was found that the limit of detection of the three methods is almost the same, while AA-DLLME has a wider linear dynamic range and the shortest analysis time. Enrichment factors of 182, 45 and 245 were achieved for AA-DLLEM, VA-DLLME, and UA-DLLME, respectively. 相似文献