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41.
We state a mild generalization of the classical Schönemann irreducibility criterion in ?[x] and provide an elementary proof. 相似文献
42.
Isolation,cytotoxic evaluation,and simultaneous quantification of eight bioactive secondary metabolites from Cicer microphyllum by high‐performance thin‐layer chromatography 下载免费PDF全文
Alamgir A. Dar Santosh K. Rath Afnan Qaudri Buddh Singh Sheikh A. Tasduq Anil Kumar Payare L. Sangwan 《Journal of separation science》2015,38(23):4021-4028
Chemical investigation of Cicer microphyllum resulted in the isolation and characterization of eight natural products viz. Stigmasterol, Oleanolic acid‐3‐acetate, Oleanolic acid, Biochanin A, Genistein, Pratensein, Chrysoeriol, and Luteolin. Herein, we report a novel, accurate, and cost‐effective high‐performance thin‐layer chromatography method for the simultaneous quantification of the isolated natural products on silica‐gel 60F254 plates using the solvent system n‐hexane/ethyl acetate/formic acid (9.0:6.5:0.8, v/v/v). Natural products were quantified after postchromatographic derivatization with ceric ammonium sulfate. The method was validated as per the International Conference on Harmonization guidelines. All calibration curves showed a good linear relationship (r > 0.9943) within the test range. Precision was assessed by intra‐ and interday tests with relative standard deviations <1.82%, accuracy validation recovery 98.38–99.57% with relative standard deviations <1.00%. On quantification, Pratensein was a major constituent (0.921%). The screening for cytotoxic activity using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay resulted into identification of Luteolin as potent molecule with IC50 3.5 and 25.6 μg/mL against murine melanoma and human epidermoid carcinoma cell lines, respectively. 相似文献
43.
K. S. Pramod V. Vijayasundaram N. Krishnakumar PL. RM. Palaniappan 《Journal of Thermal Analysis and Calorimetry》2012,108(1):133-139
This article presents the changes in the thermal properties of the control and titanium dioxide (TiO2), both nano and bulk exposed Zebrafish bones by using thermo analytical techniques. The result shows that the mass loss due
to the thermal decomposition occurs in three distinct steps due to loss of water, organic and inorganic materials. The titanium
dioxide exposed bones present a different thermal behaviour compared to the control bones. The residue masses are found to
be increased due to titanium dioxide exposure. In particular, nano titanium dioxide exposure increases the residue mass level
significantly (three fold) when compared to titanium dioxide bulk exposure. These thermal characteristics can be used as a
qualitative method to check the metal oxide intoxication in biological samples. 相似文献
44.
Saralees Nadarajah 《数学物理学报(B辑英文版)》2010,30(1):330-340
Two posterior distributions for the mean of the Laplace distribution are obtained by deriving the distributions of the product XY and the ratio X/Y when X and Y are Student's t and Laplace random variables distributed independently of each other. Tabulations of the associated percentage points are given along with computer programs for generating them. 相似文献
45.
In the present research work, four new 14-membered tetraazamacrocylic complexes of Cobalt(II), Nickel(II), Copper(II) and Zinc(II) with (1E,14E)-8,8,17,17-tetramethyl-2,5,11,14-tetraazatricyclo[13.3.1.16,10]icosa-1,5,10,14-tetraene were synthesized using the template methodology that leads to the formation of a complex of type [MLX2] in which L is a macrocyclic ligand derived from ethylenediamine (ED) and 5,5-dimethylcyclohexanedione (DCH) and X = Cl−/CH3COO−. Spectroscopic, physical, and analytical characterization of complexes was carried out with the assistance of infra-red, nuclear magnetic resonance, electron spin resonance, Ultraviolet-visible, powder X-Ray diffraction, electron spray ionization - mass spectroscopy (ESI-MS), thermogravimetric analysis, magnetic susceptibilities, and carbon hydrogen nitrogen analysis. The information regarding the monomeric and nonelectrolytic behavior was elucidated from ESI-MS and molar conductance values. Powder X-Ray diffractogram studies point toward the crystalline or amorphous nature of the complexes. All the compounds exhibited the nonelectrolytic nature. Semiempirical calculations were performed using Gaussian 09 software and quantum chemical parameters were determined. Newly designed macrocyclic complexes were examined for their antifungal and antibacterial potency by the Agar well diffusion method. In-vitro DNA binding studies were carried out in order to understand the extent and nature of binding shown by the complexes with the DNA. In addition to this, in-silico absorption distribution metabolism excretion toxicity studies were also carried out for the interpretation of drug-like properties in the newly synthesized complexes. 相似文献
46.
Imran Khan Payare L. Sangwan Alamgir A. Dar Rather A. Rafiq Mufti R. Farrukh Jagdish K. Dhar Sheikh A. Tasduq Surrinder Koul 《Journal of separation science》2013,36(16):2602-2610
Betulinic acid ( 1 ), betulinic acid‐3‐acetate ( 2 ), 3‐acetylbetulinaldehyde ( 3 ), oleanolic acid‐3‐acetate ( 4 ), 3‐β‐hydroxy‐28,19‐β‐olenolide ( 5 ), and β‐sitosterol ( 6 ) were isolated from Platanus orientalis and a high‐performance thin‐layer chromatography method was developed for their simultaneous quantification. The markers were first derivatized on the chromatogram with ceric ammonium sulfate and then high‐performance thin‐layer chromatography densitometry was carried out. Chromatographic separation of these markers was carried out on silica gel 60 plates using a ternary solvent system n‐hexane/toluene/acetone (6:3.5:1 v/v/v) as a mobile phase. For marker 1 , a deuterium (D2) lamp and wavelength of 420 nm was used. A tungsten (W) lamp was used for markers 2 and 3 at 550 nm and for 4 – 6 at 500 nm. The method was validated for accuracy, precision, LOD, and LOQ. All calibration curves showed a good linear relationship (r > 0.9919). The precision evaluated by an intra‐ and interday study showed RSDs < 2.51% and accuracy validation recovery between 95.54 and 99.33% with RSDs < 1.55%. The successful application of the validated method showed 1 as the most abundant component (4.63%) and 5 (0.017%) the least. The markers displayed a significant cytotoxic effect against human keratinocyte, mouse melanoma, and human skin epithelial carcinoma cancer cells by using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay. 相似文献
47.
MR Eskildsen AB Abrahamsen PL Gammel DJ Bishop NH Andersen K Mortensen PC Canfield 《Pramana》2002,58(5-6):903-905
We compare the results of small angle neutron scattering on the flux line lattice (FLL) obtained in the borocarbide superconductor
LuNi2B2C with the applied field along the c- and a-axes. For H‖c the temperature dependence of the FLL structural phase transition from square to hexagonal symmetry was investigated. Above
10 K the transition onset field. H
2(T), rises sharply, bending away from H
c2(T) in contradiction to theoretical predictions of the two merging. For H‖a a first order FLL reorientation transition is observed at H
tr=3–3.5 kOe. Below H
tr the FLL nearest neighbor direction is parallel to the b-axis, and above H
tr to the c-axis. This transition cannot be explained using nonlocal corrections to the London model. 相似文献
48.
49.
50.
We have grown single crystals of the psuedo-one-dimensional compound Sr3CuIrO6, a K4CdCl6-derived monoclinic structure with Cu-Ir chains along the [101] direction. We present the ac and dc magnetization behavior
of the single crystals in comparison with that of the polycrystalline form reported earlier. There is a distinct evidence
for at least two magnetic transitions, at 5 K (T
1) and 19 K (T
2), with different relative magnitudes in the single and polycrystals. The low temperature magnetic relaxation behavior of
both the forms is found to be widely different, exhibiting unexpected time dependence. 相似文献