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181.
A rapid, sensitive and specific high‐performance thin‐layer chromatographic (HPTLC) method was developed and validated for determination of gliotoxin in Aspergillus infected immunocompromised patients with invasive aspergillosis (IA). Densitometric analysis of gliotoxin was carried out in the absorbance mode at 254 nm after single‐step extraction with chloroform. The method uses TLC aluminum plates pre‐coated with silica gel 60F‐254 as a stationary phase and toluene–isoamyl alcohol–methanol (10:0.5:0.5, v/v/v) as mobile phase, which gives compact spot of gliotoxin (Rf = 0.51). The calibration curve was linear (r2 ≥ 0.994) between peak area and concentration in the tested range of 100–1000 ng spot?1 with minimum detectable range 0.025 ng μ?1 of serum sample. The mean ± SD value of slope and intercept of the standard chromatogram of gliotoxin were found to be 523.2 ± 1.555635 and 915.8 ± 30.68843, respectively. The developed method is simple, rapid, precise and less costly than earlier diagnostic methods, and different serum samples can be run on a single TLC plate for comparative analysis. The proposed method can be used to analyze gliotoxin in patient serum for easy, rapid and cost‐effective diagnosis of IA. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
182.
Kartini Ahmad Mat Ropi Mukhtar Jean-Frederic Faizal Weber Saraswati S. Velu Hiroshi Morita A. Hamid A. Hadi 《Tetrahedron》2009,65(7):1504-5660
The FeCl3-promoted oxidative cyclization/coupling of acetamidostilbenes possessing 3-methoxy, 4-methoxy and 3,5-methoxy substitutions (21), (22) and (23) is described. Only 3,5-substitution gave rise to novel indolostilbenes, each possessing two stereogenic axes (axially chiral but racemic dimers (39) and (40)). The 4-methoxy substituted acetamidostilbenes, by contrast, yielded the bisindoline dimer (36). 相似文献
183.
M. A. Tantray A. S. Shawl B. S. Arora B. Purinima K. Ahmad M. A. Khuroo 《Chemistry of Natural Compounds》2009,45(3):377-380
Three new glutinane-type triterpenes, 19α-glutin-5-en-19-ol (1), 2β,15α,21β-glutin-11-ene-2,15,21-triol (2), and 2β,19α-glutin-7,21-diene-2,19-diol (3), were isolated from the stem bark of Euonymus hamiltonianus. Their structures were determined by 1D and 2D NMR along with MS and IR.
Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 321–323, May–June, 2009. 相似文献
184.
13-Crown-4,16-crown-5,dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields.Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect. 相似文献
185.
Meysam Soleymani Ahmad Moheb Ezatolah Joudaki 《Central European Journal of Chemistry》2009,7(4):809-817
Single phase nanocrystalline La0.6Ca0.4MnO3 powder was synthesized by both the usual and a modified citrate gel precursor method, and the effects on the formation of
homogeneous nano-sized powder with a perovskite structure were investigated. In the modified method, single phase La0.6Ca0.4MnO3 powder with an average particle size of 17.2 nm was obtained when the powder was pyrolyzed at 520°C for 2 h. Its specific
surface area was 40.7 m2 g−1, about 4-fold larger than that of powder made by the usual citrate gel method.
相似文献
186.
Ahmad Umar 《Talanta》2009,77(4):1376-677
High-aspect-ratio ZnO nanowires based ultra-sensitive hydrazine amperometric sensor has been fabricated which showed a high and reproducible sensitivity of 12.76 μA cm−2 nM−1, detection limit, based on S/N ratio, 84.7 nM, response time less than 5 s, linear range from 500 to 1200 nM and correlation coefficient of R = 0.9989. This is the first report in which such a very high-sensitivity and low detection limit has been achieved for the hydrazine sensors by using ZnO nanostructures modified electrodes. Therefore, this work opens a way to utilize simply grown ZnO nanostructures as an efficient electron mediator to fabricate efficient hydrazine sensors. 相似文献
187.
Upon addition of permanganate to a solution of tryptophan (Trp), yellow-brown color species appears within the time of mixing of tryptophan in absence and presence of cetyltrimethylammonium bromide (CTAB), which was stable for some days. Spectroscopic and kinetic evidences suggest the formation of water-soluble colloidal MnO2 as the most stable reduction product of MnO4−. Carbon dioxide and ammonia are not formed as the oxidation products. Carbon–carbon double bond of indole moiety of Trp is responsible for the fast reduction of permanganate. Cetyltrimethylammonium bromide catalyses the permanganate oxidation of Trp with a rate enhancement of ca. 200-fold. Sub- and postmicellar catalytic effect of CTAB ascribed to the association/incorporation/solubilization of both reactants (MnO4− and Trp) with the CTAB aggregates and into the Stern layer of cationic micelles. Quantitative kinetic analysis of the rate constant–[CTAB] data has been performed on the basis of modified pseudo-phase model of the micelles. A comparison was made of the oxidation rates of different amino acids by permanganate. The order of the effectiveness was as follows: tryptophan tyrosine phenylalanine. 相似文献
188.
JPC – Journal of Planar Chromatography – Modern TLC - High-performance liquid chromatography (HPLC) has been the most popular choice for analysis of tamoxifen citrate. In this study,... 相似文献
189.
Riaz N Anis I Malik A Ahmed Z Aziz-ur-rehman Muhammad P Nawaz SA Choudhary MI 《Chemical & pharmaceutical bulletin》2003,51(3):252-254
Paeonins A and B, new monoterpene galactosides have been isolated from the chloroform-soluble fraction of the roots of Paeonia emodi and showed potent lipoxygenase inhibitory activity. The structures of 1 and 2 have been assigned on the basis of spectral analysis including one- and two-dimensional NMR techniques. 相似文献
190.
Temperature-sensitive micron-sized monodispersed composite polymer particles were prepared by seeded copolymerization of
dimethylaminoethyl methacrylate and ethylene glycol dimethacrylate with 1.77 μm-sized monodispersed polystyrene seed particles.
The change in surface property at temperature above and below 35 °C was examined by differential scanning calorimetry, trypsin
activity and the adsorption/ desorption behaviors of low molecular weight cationic emulsifier as well as biomolecules.
Received: 6 August 1997 Accepted: 16 January 1998 相似文献