Biomedical subjects

A Abbaspour

Publications and source records attributed to A Abbaspour.

5 recordsLinked to original sources

PubMed2006

Application of spectral beta-correction method and partial least squares for simultaneous determination of V(IV) and V(V) in surfactant media.

Simultaneous determination of V(IV) and V(V) was performed by application of partial least squares when the calibration matrix was obtained using beta-correction spectra. Two reaction between V(IV) and V(V) and Pyrogallol Red as a ligand in presence of cethyltrimethylammoniumbromide (CTAB) media has been investigated and applied to the simultaneous spectrophotometric determination of these species. The parameters controlling behavior of the system were investigated and optimum conditions selected. Determinations were made over the concentration range 0.6-4.50 microg ml-1 of V(IV) and 0.3-5.50 microg ml-1 of V(V). Applying this method to simultaneous determination of these metal ions in several real samples with total relative standard error less than 5% validated the proposed method.

Least-Squares Analysis↗

PubMed2005

Application of principle component analysis-artificial neural network for simultaneous determination of zirconium and hafnium in real samples.

Determination of zirconium and hafnium were done by applying singular value decomposition and a feed forward Neural Network Algorithm with back propagation of error. The determination of trace amounts of mixtures of Zr(IV) and Hf(IV) in various matrices (river, tap and industrial wastewater) were investigated by PC-ANN using the complexes formed between Alizarin Red S, Zr and Hf. The results showed that measurement is possible in the ranges of 0.03-3.4 and 0.2-7.0 microg ml-1 for Zr(IV) and Hf(IV), respectively. The detection limits were 0.02 and 0.08 microg ml-1 for Zr(IV) and Hf(IV), respectively. The results also show very good agreement between true and predicted concentration values and have the ability to use in routine analysis.

Anthraquinones↗

PubMed2005

Simultaneous determination of phenytoin, barbital and caffeine in pharmaceuticals by absorption (zero-order) UV spectra and first-order derivative spectra--multivariate calibration methods.

The quantitative predictive abilities of partial least squares (PLS-1) and principle component regression (PCR) on absorption (zero-order) UV spectra are compared with the results obtained by the use of these multivariate calibration methods on first-order derivative spectra. Both approaches were satisfactorily applied to the simultaneous determination of these drugs in synthetic and pharmaceutical mixtures. Significant advantages were found in the simultaneous determination of phenytoin, barbital and caffeine in binary and ternary mixtures, by application of different multivariate calibration methods when the calibration matrix was performed using the first-order derivative spectra. The proposed method was validated by applying it to the analysis of binary and ternary mixtures of phenytoin, barbital and caffeine. Determinations were made over the concentration ranges of 0.24-22.0, 0.01-27.0 and 0.049-27.0 microg ml(-1) for phenytoin, barbital and caffeine, respectively, in the binary and 0.45-22.0, 0.05-26.0 and 0.05-20.0 microg ml(-1) for phenytoin, barbital and caffeine, respectively, in the ternary mixtures. The relative standard errors in the determinations were less than 3% in most cases.

Barbital↗

PubMedDate not supplied

A study of tobacco carcinogenesis. XLII. Bioassay in A/J mice of some structural analogues of tobacco-specific nitrosamines.

The tumorigenic activities in A/J mouse lung of the tobacco-specific nitrosamines, N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and several structural analogues were evaluated. The analogues were N-nitrosopyrrolidine (NPYR), 5'-carboxy-N'-nitrosonornicotine (CNNN), N-nitrosoproline (NPRO) and 1-(3-pyridyl)-2-buten-1-one (PBO). The results were as follows (dose in mumol per mouse/lung tumors per mouse): NNN (100/1.8 +/- 1.4); NPYR (100/3.9 +/- 1.5); CNNN (200/0.3 +/- 0.5); CNNN (100/0.5 +/- 0.6); NPRO (100/0.6 +/- 0.7); NNK (20/7.2 +/- 3.4); PBO (20/0.7 +/- 1.0); saline control (0.0.5 +/- 0.7). Several conclusions were drawn from this assay. NNK and NPYR were more tumorigenic than NNN. CNNN was non-tumorigenic and thus appears to have potential as a monitor for endogenous formation of tobacco-specific nitrosamines. The alpha,beta-unsaturated ketone PBO does not appear to be an ultimate tumorigen of NNK or NNN.

Adenoma↗

PubMedDate not supplied

Reinvestigation of the conformations of a variety of hexahydrobenzo[c]phenanthridine alkaloids by 470 MHz PMR and 50 MHz CMR spectroscopy.

The high resolution pmr and cmr spectra of a variety of benzo[c]phenanthridine alkaloids and their CF3COOD salts were examined. The chemical shift of H-14 was found to be a reliable indicator of the orientation of the N-methyl group. The conformations of the C rings were assigned on the basis of the coupling constants between H-11 and the two H-12 protons. On the basis of the pmr spectra of (+)-14-epicorynoline (9) and (+/-)-14-epicorynoline-6,6,12 alpha-d3 (13), a revision of certain previous C ring conformations is indicated.

Alkaloids↗