排序方式: 共有118条查询结果,搜索用时 46 毫秒
41.
Karima Horchani-Naifer Jaouher Amami Mokhtar Férid 《中国稀土学报(英文版)》2008,26(6):765-769
Crystals of thallium-holmium polyphosphate T1Ho(PO3)4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of T1Ho(PO3)4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions: a=1.02225(3) nm, b=0.88536(2) nm, c=1.09541(4) nm, β=105.888(1)°, V=0.95354(5) nm^3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1(F^2)=0.0442 and Rw(F^2)=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eightfold coordination. The structure of T1Ho(PO3)4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350--4000 cm^-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen. 相似文献
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Amandine Coum Fanny Noury Elise Bannier Karima Begriche Bernard Fromenty Yves Gandon Hervé Saint-Jalmes Giulio Gambarota 《Magma (New York, N.Y.)》2016,29(1):29-37
Objective
To investigate the effect of water suppression on the hepatic lipid quantification, using the LCModel.Materials and methods
MR spectra with and without water suppression were acquired in the liver of mice at 4.7 T and patients at 3 T, and processed with the LCModel. The Cramér–Rao Lower Bound (CRLB) values of the seven lipid resonances were determined to assess the impact of water suppression on hepatic lipid quantification. A paired t test was used for comparison between the CRLBs obtained with and without water suppression.Results
For the preclinical data, in the high (low) fat fraction subset an overall impairment in hepatic lipid quantification, i.e. an increase of CRLBs (no significant change of CRLBs) was observed in spectra acquired with water suppression. For the clinical data, there were no substantial changes in the CRLB with water suppression. Because (1) the water suppression does not overall improve the quantification of the lipid resonances and (2) the MR spectrum without water suppression is always acquired for fat fraction calculation, the optimal data-acquisition strategy for liver MRS is to acquire only the MR spectrum without water suppression.Conclusion
For quantification of hepatic lipid resonances, it is advantageous to perform MR spectroscopy without water suppression in a clinical and preclinical scenario (at moderate fields).43.
Karima Dhaouadi Faten Raboudi Lorena Funez-Gomez David Pamies Carmen Estevan Mohamed Hamdaoui Sami Fattouch 《Food Analytical Methods》2013,6(1):45-53
The traditionally derived syrup of Opuntia ficus-indica fruit is commonly used in homemade confectionery. Herein, the aqueous-acetone extract prepared from the Tunisian O. ficus-indica syrup was investigated. The qualitatively and quantitatively polyphenolic content was analysed using reversed-phase high-performance liquid chromatography–diode array detection (RP-HPLC–DAD) coupled to electrospray ionisation–mass spectrometry (ESI–MS). The extract contained 19.95?±?2.01 mg phenolics per gram of fresh starting material with isorhamnetin 3-O-robinobioside as the major compound (22.76%). The syrup extract showed strong antioxidant potentials as assessed by both ABTS and DPPH functional methods. It exhibited effective antimicrobial activity, particularly against Staphylococcus aureus and Staphylococcus epidermidis with a minimal bactericide concentration (MBC) of 1.3 mg phenolics/ml. Furthermore, at final concentrations in the range of 41.38–186.25 μg polyphenols/ml, the extract decreased human SH-SY5Y neuroblastoma and 3T3 fibroblast in vitro cell viability in a dose- and time-dependent manner compared to non-treated control cells. The observed effects were significantly (P?<?0.05) high against cancer lines. Extract concentrations higher than 106.43 μg/ml reduced cancer cells viability to 50–60% 1–3 h post-treatment. Further in vivo insight studies should emphasise and validate the herein obtained results. 相似文献
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Ameur Elaissi Karima Hadj Salah Samia Mabrouk Khouja Mohamed Larbi Rachid Chemli Fethia Harzallah-Skhiri 《Food chemistry》2011
The essential oils of twenty Eucalyptus species harvested from Zerniza and Souinet arboreta (North West and North of Tunisia), were screened for their antibacterial activities by the agar disc diffusion method. Eighteen major compounds, identified by GC and GC/MS, have been retained for the study of the chemical and biological activity variability. The main ones were 1,8-cineole followed by α-pinene, p-cymene, borneol, cryptone, spathulenol, viridiflorol and limonene. The chemical principal components analysis identified 10 chemotypes, however that of the inhibition zone diameter (izd) of growth bacteria separated 5 groups of Eucalyptus oils, characterised by their antibacterial inhibition ability. The most sensitive strain was the Gram positive Staphylococcus aureus with that of E. odorata oil (16.0 ± 1.0 mm izd), while the most resistant bacteria was Pseudomonas aeruginosa. Some correlation between the amount of 1,8-cineole, p-cymene, α-pinene, or of cryptone and the antibacterial activity were observed. 相似文献
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The importance of using renewable feed stocks in the textile industry area are expected to increase in the next few decades due to the limited natural resources coupled with an increased environmental legislation for eco-friendly and sustainable technologies. This research work focuses on the possible future applications of microwave irradiation in this field. Alkyd resins with highly distinct characters and reactive properties, based entirely on commercially available renewable resources, including sunflower or soybean oil, are prepared and characterized. The rheological properties, apparent viscosity of prepared binders, and roughness of the prints were described. The study was extended to application of the prepared alkyd resins as a binder in pigment printing operations onto cotton fabric by using a flat screen technique. The optimum curing conditions as well as the color strength and fastness properties of pigment printed areas to light, washing, perspiration and crocking, were evaluated. 相似文献
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Meier Thomas Gandt Karima Echterhof Thomas Pfeifer Herbert 《Metallurgical and Materials Transactions B》2017,48(6):3329-3344
Metallurgical and Materials Transactions B - The following paper describes an approach to process modeling and simulation of the gas phase in an electric arc furnace (EAF). The work presented... 相似文献
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Use of a PbO2 electrode of a lead-acid battery for the electrochemical degradation of methylene blue
Samia Saaidia Zahia Benredjem Ahmed Mehellou Abdelhak Djemel Karima Barbari 《分离科学与技术》2017,52(9):1602-1614
In this work, the electrochemical degradation efficiency of synthetic azo dye, methylene blue, at positive electrode PbO2 of lead-acid battery was investigated. The structure and morphology of the electrode was investigated by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectrometry. The influence of several operating parameters on electro-oxidation of 100 mL of methylene blue solution 100 mg/L was studied. Results indicated that lead-acid battery electrode is effective for removing color and chemical oxygen demand (COD). It is found that current density, the stirring speed, and the supporting electrolyte concentration have a positive effect on decolorization and mineralization, and no significant effect of the distance between the electrodes on methylene blue degradation and COD removal was observed. By contrast, the percentage of color and COD removal decreases with increasing of pH. Kinetic analysis of the results revealed that the COD removal follows a pseudo-first-order kinetics. 相似文献
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