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61.
E. Cau?t T. Carette C. Lauzin J. G. Li J. Loreau M. Delsaut C. Nazé S. Verdebout S. Vranckx M. Godefroid J. Liévin N. Vaeck 《Theoretical chemistry accounts》2012,131(8):1-17
We present a summary of the research activities of the “Quantum Chemistry and Atomic Physics” theoretical group of the “Chimie Quantique et Photophysique” Laboratory at Université Libre de Bruxelles. We emphasize the links between the three orientations of the group: theoretical atomic spectroscopy, structure, and molecular dynamics and list the perspectives of our collaboration. 相似文献
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Effect of particle size distribution on magnetic behavior of nanoparticles with uniaxial anisotropy 下载免费PDF全文
S Rizwan Ali Farah Naz Humaira Akber M Naeem S Imran Ali S Abdul Basit M Sarim Sadaf Qaseem 《中国物理 B》2018,(9)
The effect of particle size distribution on the field and temperature dependence of the hysteresis loop features like coercivity(H_C), remanence(M_R), and blocking temperature(T_B) is simulated for an ensemble of single domain ferromagnetic nanoparticles with uniaxial anisotropy. Our simulations are based on the two-state model for T T_B and the metropolis Monte-Carlo method for T T_B. It is found that the increase in the grain size significantly enhances H_C and T_B. The presence of interparticle exchange interaction in the system suppresses H_C but causes MRto significantly increase.Our results show that the parameters associated with the particle size distribution(D_(d,δ)) such as the mean particle size d and standard-deviation δ play key roles in the magnetic behavior of the system. 相似文献
65.
Shama Naz Antonia Garcia Magdalena Rusak Coral Barbas 《Analytical and bioanalytical chemistry》2013,405(14):4849-4858
In the search for a noninvasive and reliable rapid screening method to detect biomarkers, a metabolomics fingerprinting approach was developed and applied to rat serum samples using capillary electrophoresis coupled to an electrospray ionization-time of flight-mass spectrometer (CE–TOF-MS). An ultrafiltration method was used for sample pretreatment. To evaluate performance the method was validated with carnitine, choline, ornithine, alanine, acetylcarnitine, betaine, and citrulline, covering the entire electropherogram of pool of rat serum. The linearity for all metabolites was >0.99, with good recovery and precision. Approximately 34 compounds were also confirmed in the pool of rat serum. The method was successfully applied to real serum samples from rats with ventilator-induced lung injury, an experimental rat model for acute lung injury (ALI), giving a total of 1163 molecular features. By use of univariate and multivariate statistics 18 significant compounds were found, of which five were confirmed. The involvement of arginase and nitric oxide synthase has been proved for other lung diseases, meaning the increase of asymmetric dimethyl arginine (ADMA) and ornithine and the decrease of arginine found were in accordance with published literature. Ultimately this fingerprinting approach offers the possibility of identifying biomarkers that could be regularly screened for as part of routine disease control. In this way it might be possible to prevent the development of ALI in patients in critical care units. Figure
A fingerprinting approach in serum using capillary electrophoresis and mass spectrometry 相似文献
66.
Shahid Khan Durrani S. Naz M. Nadeem A. A. Khan 《Journal of Thermal Analysis and Calorimetry》2014,116(1):309-320
Nanocrystalline magnesium chromite spinel was synthesized through hydrothermal reaction of metal nitrate solutions in stoichiometric amount at different pH, temperature and time intervals. The synthesized products were characterized for crystallinity, phase identification, and surface morphology by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD patterns showed that as-synthesized product remained amorphous up to 250 °C. However, well-crystallized magnesium chromite spinel structure is formed after calcination at 850 °C. Rietveld refinement study confirms the formation of single-phase cubic structure MgCr2O4 with lattice parameter a = 8.3347 Å, and Fd3m space group. The as-processed MgCr2O4 products showed extensive XRD line broadening, and the mean crystallite size of such crystals was found to be mainly in size range of 85–124 nm. Surface SEM images of calcined specimens revealed that the matrix is uniform, and no separation of secondary phase was detected. Thermal stability was examined by thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry. TG/DTA reveals that MgCr2O4 is thermally stable above 700 °C. Fourier transform infrared (FTIR) spectra studies shows two strong bands, one around 600 cm?1 which is attributed to the intrinsic vibrations of tetrahedral and other at 400 cm?1 is due to octahedral one. FTIR confirms the formation of metal oxides. The bandgap energy was estimated by absorption spectroscopy in ultraviolet–visible range and was found to be 0.693 eV for MgCr2O4 specimen sintered at 1,000 °C. Isothermal shrinkage characteristic and coefficient of thermal expansion were determined by dilatometry. The powder specimens showed excellent densification at 1,250 °C temperature and uniformly fine grain sintered ceramics (>90 % relative density) with submicron grain size (2–5 μm) were obtained after sintering at 1,000–1,250 °C. Impedance studies were carried out at room temperature and equivalent circuit model (R 1 Q 1) (R 2 Q 2) (R 3 Q 3) is used to explain different relaxation processes. We report largest impedance values i.e., 6.74 × 108 Ω, reduced dielectric constant (≈1.0), and low tangent loss (0.8) for MgCr2O4 sintered at 1,250 °C. 相似文献
67.
Khan Jehangir Sadia Maria Shah Syed Wadood Ali Naz Robina Ali Faiz 《Journal of fluorescence》2021,31(6):1759-1770
Journal of Fluorescence - The ligand 2,6-bis(E)-4-methylbenzylidine)-cyclohexan-1-one sensor has been synthesized as a fluorescence-on sensor/probe for the trace level detection of chromium III... 相似文献
68.
Aydin Tavman Naz M. Agh-Atabay Abdollah Neshat Fahrettin Gucin Basaran Dulger Durata Haciu 《Transition Metal Chemistry》2006,31(2):194-200
2-(5-H/methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenol (HLx:X=1–4) ligands and their iron(III) nitrate complexes have been synthesized and characterized. In all of the complexes, the
ligands are bidentate, via one imine nitrogen atom and a phenolate oxygen atom. The coordination is completed with a bidentate nitrate anion, and a
water molecule. Elemental analysis, molar conductivity, magnetic susceptibility, FT-Raman, FT-IR (mid i.r., far i.r.), UV–visible
and as well as quantum chemical calculations performed with CACHE are in agreement with a 1:1 electrolyte structures that
are mononuclear, and distorted 5-coordinate square pyramidal. The antimicrobial activities of free ligands, their hydrochloride
salts and the complexes were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) toward nine bacteria,
each with multiple, fresh clinical isolates, and the results are compared with those for penicillin-g, ampicillin, cefotaxime,
vancomycine, oflaxacin and tetracycline. Antifungal activities were reported for Kluyveromyces fragilis, Rhodotorula rubra, Candida albicans, Hanseniaspora Guilliermondii and Debaryomyces hansenii yeasts, each with multiple isolates, and the results were referenced against nystatin, ketaconazole and clotrimazole antifungal
agents. In most cases, the compounds tested showed broad-spectrum (Gram+ and Gram−) activities that were either more active or as potent as the references particularly as antifungal agents. 相似文献
69.
Tarannum Naz Joanne Packer Ping Yin Joseph J. Brophy Hans Wohlmuth Dane E. Renshaw 《Natural product research》2016,30(6):693-696
Lophostemon suaveolens is a relatively unexplored endemic medicinal plant of Australia. Extracts of fresh leaves of L. suaveolens obtained from sequential extraction with n-hexane and dichloromethane exhibited antibacterial activity in the disc diffusion and MTT microdilution assays against Streptococcus pyogenes and methicillin sensitive and resistant strains of Staphylococcus aureus (minimum bactericidal concentration < 63 μg/mL). The dichloromethane extract and chromatographic fractions therein inhibited nitric oxide in RAW264.7 murine macrophages (IC50 3.7–11.6 μg/mL) and also PGE2 in 3T3 murine fibroblasts (IC50 2.8–19.7 μg/mL). The crude n-hexane, dichloromethane and water extracts of the leaves and chromatographic fractions from the dichloromethane extract also showed modest antioxidant activity in the ORAC assay. GC–MS analysis of the n-hexane fraction showed the presence of the antibacterial compounds aromadendrene, spathulenol, β-caryophyllene, α-humulene and α-pinene and the anti-inflammatory compounds β-caryophyllene and spathulenol. Fractionation of the dichloromethane extract led to the isolation of eucalyptin and the known anti-inflammatory compound betulinic acid. 相似文献
70.
A quantitative analytical method using gas chromatography/mass spectrometry (GC/MS) to determine urinary concentrations of eight progesterones and corticosteroids has been developed. After enzymatic hydrolysis with beta-glucouronidase/arylsulfatase, urine samples were extracted by simple one-step solid-phase extraction. Obtained extracts were derivatized with a mixture of N-methyl-N-(trimethylsilyl)trifluoroacetamide/ammonium iodide/dithiothreitol and determined by GC/MS in selected ion monitoring mode to increase the sensitivity. d(4)-Cortisol and d(9)-progesterone were used as internal standards for two different steroid groups. The linear correlation coefficient was in the range of 0.9913 to 0.9998 and recoveries were over 80% for all compounds. Precision and accuracy were in the range of 0.9-18.1 and 84.1-118.7%, respectively. The limit of quantitation (LOQ) was 10 ng/mL for 11-deoxycorticosterone and 21-deoxycortisol and 5 ng/mL for all other analytes. The developed method was successfully applied on pelvic organ prolapsed patients (n = 10, age: 67.9 +/- 4.9) and post-menopausal (n = 10, age: 63.6 +/- 5.5) control women. Urinary levels of most progesterones and corticosteroids except 11-deoxycorticosterone decreased but only that of 17 alpha-hydroxyprogesterone significantly decreased in patients compared with the control groups. Thus, it is concluded that progesterones could be a factor in the pathogenesis of pelvic organ prolapse, and, among them, 17 alpha-hydroxyprogesterone could be a biomarker for pelvic organ prolapse. 相似文献