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991.
M. Ali A. H. Khan A. K. M. Wahiduzzaman M. A. Malek 《Journal of Radioanalytical and Nuclear Chemistry》1997,219(1):81-87
The trace element concentrations of eight elements (Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb) in the scalp hair of 49 normal and 55 malnourished children of the Bangladesh population, in the age group of 1 to 5 years were analyzed by the external beam PIXE method to establish their baseline values in normal children for pre-diagnostic screening of deficiency and excess in malnutrition. The results of this investigation show that the ranges of trace elements in hair are somewhat wide. For example, the normal Zn level has the range of 63–377 g·g–1 for 49 subjects. The reasons for these large individual deviations are unknown till now. The average of the elemental concentrations between normal and malnourished groups are compared (t-test,p<0.05). A correlation study has been done on each pair of original data by a non-parametric Speaman's rank test. The frequency distributions of the elements are presented and the results are compared with the data reported in the literature. A substantive correspondence between the present data in hair of both the study groups and the literature values from different countries have been observed but they did not show any regular dependence on the nutritional status of the subjects. Only the low Cu content in the hair of malnourished group can possibly be linked with nutritional disorders as evidenced from this study.Part of a Ph.D. Thesis. 相似文献
992.
993.
Spectrophotometric Determination of Prochlorperazine Maleate in Pure and Pharmaceutical Preparations
Tehseen Aman Zeeshan Majeed Asrar Ahmad Kazi Islam Ullah Khan 《Mikrochimica acta》2002,138(1-2):13-17
Prochlorperazine maleate reacts with 1-naphthylamine and sodium nitrite, after heating for 110 s at 80 °C to give an orange
red colour having maximum absorbance at 460 nm. The reaction is selective for prochlorperazine maleate with 0.01 mg/mL as
visual limit of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer’s
law from 0.01 mg/10 mL to 0.33 mg/10 mL of prochlorperazine maleate and the relative standard deviation is 0.68%. The quantitative
assessment of tolerable amounts of other drugs is also studied.
Received September 22, 2000. Revision June 19, 2001 相似文献
994.
Caliş I Bedir E Kirmizibekmez H Ersöz T Dönmez AA Khan IA 《Natural product research》2005,19(5):493-501
In addition to rare phenylethanoid triglycosides, myricoside and its dimetylether derivative serratumoside A {3-hydroxy,4-methoxy-beta-phenylethoxy-O-beta-D-apiofuranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->3)-4-O-feruloyl-beta-D-glucopyranoside}, a new phenylethanoid glycoside, myricoside-3"-O-methylether {3,4-dihydroxy-beta-phenylethoxy-O-beta-D-apiofuranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->3)-4-O-feruloyl-beta-D-glucopyranoside} along with a new neolignan glucoside, (7S, 8R)-dehydroconiferyl alcohol-8-5'-dehydroconiferyl aldehyde 4-O-beta-D-glucopyranoside were isolated from the aerial parts of Phlomis oppositiflora. The structures of the new compounds were identified by means of spectroscopic (UV, IR, 1D- and 2D-NMR, and LC-ESIMS) methods. 相似文献
995.
Fused NaFeCl(4) shows a great affinity for moisture, which reacts chemically with it. By passage through a heated column filled with NaFeCl(4) coated on bioglass, gases such as nitrogen are found to have retained some moisture when dried over a molecular sieve. The compound also acts as a self-indicator, as the colour changes from yellow to brown after the reaction. It is more efficient than molecular sieves and is regenerated by passing HCl gas through the column. 相似文献
996.
Edward W. Abel A.Rauf Khan Kenneth Kite Keith G. Orrell Vladimir Šik 《Journal of organometallic chemistry》1978,145(2):C18-C20
Adducts of the type Me3PtXL (X = C1, Br, I; L = MeSCH2CH2SMe) exhibit pyramidal inversion at individual sulphur atoms, whereas the adducts (Me3PtX)2L′ (L′ = MeSCH2SMe, X = C1, Br, I) exhibit both ring inversion, and synchronous inversion about both sulphur atoms. 相似文献
997.
Torsional Motion in (tert‐Butyl)ammonium Hemispheraplexes: Rotational Barriers and Energy of Binding
EmilyF. Maverick CarolynB. Knobler Saeed Khan JamesW. Canary IraB. Dicker KennethN. Trueblood 《Helvetica chimica acta》2003,86(5):1309-1319
The ADPs (ADPs=atomic anisotropic displacement parameters) from the single‐crystal X‐ray studies of nine related TBA+ (TBA+=(tert‐butyl)ammonium) hemispheraplexes are analyzed, and the results compared to the free energy of binding of this guest by the nine hosts. The lipophilic hosts (Fig. 1) were synthesized over a number of years, with increasing pre‐organization for and specificity of binding. Structural studies for six of the complexes have been published, but the remaining three structures, including those of the strongest binders of TBA+, are disordered and have only now been completed. New area‐detector data has been analyzed for the TBA+ClO complexes of 5 and of 8 at two temperatures, while the original data for 9 ?TBA+SCN? has been treated with a disorder model. In addition, improved models are presented for the complexes of 6 and 7 . Methods for assessing the precision of the ADP analyses are discussed. Although most of the structures are imprecise, the TBA+ groups do demonstrate some of the characteristics of independent motion. The general trend in calculated libration amplitudes for the TBA+ group suggests that the guests with the greatest free energy of binding, and the shortest distances from N+ to the ligand plane, are those with the highest barriers to internal rotation. 相似文献
998.
A new 9,19-cyclolanostane-type triterpene xyloside (1), from the rhizomes of Cimicifuga racemosa, has been isolated together with four known saponins; cimiaceroside A, 25-O-methylcimigenol-3-O-beta-D-xylopyranoside, 27-deoxyactein and 23-O-acetylshengmanol-3-O-beta-D-xylopyranoside. The structure of the new compound was established as 16beta,23:22beta,25-diepoxy-12-acetoxy-3beta,23,24b eta-trihydroxy-9,19-cyclolanost-7-ene-3-O-beta-D-xylopyranoside . For the structure elucidation, 1D- and 2D-NMR experiments and high resolution electrospray ionization Fourier transformation mass spectrometry (HRESIFTMS) were used. 相似文献
999.
The kinetics of hydrolysis and reduction of the diperiodatoargentate(III) ion (DPA) has been studied in aqueous acidic medium
spectrophotometrically. Upon dilution the silver (III) complex was found to be unstable in the presence of H2O. Addition of [H+], largely increased the hydrolysis rate, whereas [OH−] does not have any effect. Under pseudo-first-order conditions ([paracetamol] > [DPA]), the reduction rate was very fast.
Second-order conditions were used to determine the reaction rate. The reaction was acid-catalyzed and the rate decreased by
the addition of periodate. The Arrhenius equation was valid for the reaction. The changes observed in the direction of the
rate constant-[H+] profile correspond to aquation of the diperiodatoargentatate(III) complex. The proposed mechanism and the derived rate law
are consistent with the observed kinetics. 相似文献
1000.