Micromethod for the analysis of the four commonly used antiepileptic drugs using a jet tube column

We describe a simple method for the determination of phenobarbital, diphenylhydantoin, carbamazepine, and primidone in serum, by use of gas-liquid chromatography with temperature programming. The methylated derivatives of these anticonvulsants were well resolved, as was 5-(p-methylphenyl)-5-phenylhydantoin, the internal standard. In this procedure we used the jet tube for separation of the drug from the serum. The proposed procedure requires only 100 μl of serum and can be done in less than 30 min. The lower limit of detection for each of the drugs is 0.5 mg/liter. Analytical recoveries of drug from serum were excellent and peak height and concentration were linearly related up to twice the toxic concentration for serum.     

Characterization of the new Bi∼6.2Cu∼6.2O8(PO4)5 oxyphosphate; a disordered compound containing 2- and 3-O(Bi, Cu)4 tetrahedra—wide polycationic ribbons

The present work is dedicated to the XRD, ED and HREM characterization of a new bismuth copper oxyphosphate Bi_∼6.2Cu_∼6.2O₈(PO₄)₅ (a=11.599(2)Å, , c=37.541(5)Å, R₁=0.0755, Rw₂₌0.174, G.S Pn2₁a). The relatively long size of its c parameter is due to the arrangement along this direction of two kinds of ribbon-like polycations formed by edge sharing O(Bi, Cu)₄ tetrahedra. The existence of such cations is characterized by the b∼5.2 Å value intrinsic to the ribbons structure and commonly found in bismuth oxyphosphate materials. In the title compound, 2-tetrahedra wide [Bi_∼2.4Cu_∼3.6O₄]^6.4+ and 3-tetrahedra wide [Bi_∼5Cu_∼3O₆]⁹⁺ ribbons are isolated by phosphate groups and alternate along c. The interstitial site created between two different sizes ribbons is occupied by Cu²⁺ cations disordered over several close crystallographic sites. The mixed Bi³⁺/Cu²⁺ nature of certain edge-of-ribbons positions induces a disorder over several configurations of the phosphate groups. The concerned oxygen atoms form the environment of the disordered interstitial Cu²⁺ cations which occupy tunnels formed by the phosphate anions. The high-resolution electron microscope study enables a precise correlation between the observed images and the refined crystal structure, evidencing the polycations visualization. Furthermore, this material being the second example of partially disordered compound similar chemical system, some topological rules can be deduced. The b-axis doubling was observed by ED and HREM and is assigned to the ordering of interstitial Cu²⁺ within tunnels cations. A partial intra-tunnel ordering was also observed.     

Note on the susceptibility exponent for two-dimensional percolation

Analyses of mean site content, mean bond content, mean perimeter and related quantities give a susceptibility diverging as (p _c –p)^–, with 2.41±0.025. This exponent disagrees with some earlier estimates but it is consistent with the (p _c –p)^–2.388... divergence predicted by the formulas of den Nijs, Nienhuis et al. and Pearson.     

Unexpected reactivity of trifluoromethylated olefins with indole: a mechanistic investigation

Several trifluoromethylated compounds were reacted with indole sodium salt, leading to monofluorinated compounds. The unexpected products formation was rationalized by DFT calculations.     

Influence of hydrogen bonds on the molecular structure and conformations of two (C30H48O2) pentacyclic triterpene isomers

The structural study of two (C₃₀H₄₈O₂) pentacyclic triterpene (PCTT) isomers is presented. These terpenes, known as 30-hydroxy-lup-20(29)-en-3-one (1) and (11α)-11-hydroxy-lup-20(29)-en-3-one (2), were isolated from Maytenus imbricata Mart. Ex Reissek (Celastraceae). The molecular structure of 1 and 2 differs in the position of the hydroxyl group. Both compounds crystallize in non-centrosymmetric space groups with two molecules in the asymmetric unit. The crystal structure of 1 shows a triclinic P1 space group (a = 9.5518(1) ?, b = 9.7083(1) ?, c = 14.4696(2) ?, α = 93.832(1)°, β = 102.833(1)°, and γ = 103.307(1)°), while compound 2 crystallizes in a monoclinic P2₁ one (a = 13.4439(16) ?, b = 14.4463(14) ?, c = 13.5224(9) ? and β = 99.703(8)°). The two molecules independent by symmetry of 1 differ slightly due to the presence of static disorder in oxygen atoms. In addition, the intermolecular geometries of 1 and 2 were analysed, and in each isomer the crystal packing is stabilized by O-H…O intermolecular hydrogen bonds and van der Waals forces.     

A value on ′AN

We prove here the existence of a value (of norm 1) on the spaces N A and even A N, the closure in the variation distance of the linear space spanned by all games f, where is a non-atomic, non-negative finitely additive measure of mass 1 and f a real-valued function on [0,1] which satisfies a much weaker continuity at zero and one. 1991 Mathematics Subject Classification. 90A08, 90A07This research was in part supported by the Belgian Programme on Interuniversity Poles of Attraction, initiated by the Prime Ministers Science Policy Office.