p1,n1 salts: Self-assembled supramolecular structures sequestering racemates. Diastereomeric separation and enantiomeric enrichment of trans-chrysanthemic acid

The occurrence of p1,n1 salts can be exploited to sequester racemates; an application to technical mixtures of chrysanthemic acids (ChA) allowed the separation of trans- and cis-ChA and the recovery of the excess enantiomer of trans-ChA.     

Diffusion with interactions between two types of particles and Pressureless gas equations

We construct two d-dimensional independent diffusions $\text{X}{}_{\mathrm{t}}{}^{\mathrm{a}}\text{=a+∫}{}_0{}^{\mathrm{t}}\text{u(X}{}_{\mathrm{s}}{}^{\mathrm{a}}\text{,s)}\text{d}\text{s+νB}{}_{\mathrm{t}}{}^{\mathrm{a}}\text{,}\text{X}{}_{\mathrm{t}}{}^{\mathrm{b}}\text{=b+∫}{}_0{}^{\mathrm{t}}\text{u(X}{}_{\mathrm{s}}{}^{\mathrm{b}}\text{,s)}\text{d}\text{s+νB}{}_{\mathrm{t}}{}^{\mathrm{b}}$, with the same viscosity ν≠0 and the same drift u(x,t)=(pρ_t^a(x)v₁+(1?p)ρ_t^b(x)v₂)/(pρ_t^a(x)+(1?p)ρ_t^b(x)), where ρ_t^a,ρ_t^b are respectively the density of X_t^a and X_t^b. Here $\text{a,b,v}{}_1\text{,v}{}_2\text{∈}\text{R}{}^{\mathrm{d}}$ and p∈(0,1) are given. We show that $\text{(ρ}{}_{\mathrm{t}}\text{(x)=pρ}{}_{\mathrm{t}}{}^{\mathrm{a}}\text{(x)+(1?p)ρ}{}_{\mathrm{t}}{}^{\mathrm{b}}\text{(x),u(x,t):}\text{t?0,}\text{x∈}\text{R}{}^{\mathrm{d}}\text{)}$ is the unique weak solution of the following pressureless gas system

such that $\text{ρ}{}_{\mathrm{t}}\text{(x)}\text{d}\text{x→pδ}{}_{\mathrm{a}}\text{+(1?p)δ}{}_{\mathrm{b}}\text{,}\text{u(x,t)ρ}{}_{\mathrm{t}}\text{(x)}\text{d}\text{x→pv}{}_1\text{δ}{}_{\mathrm{a}}\text{+(1?p)v}{}_2\text{δ}{}_{\mathrm{b}}$ as t→0+. To cite this article: A. Dermoune, S. Filali, C. R. Acad. Sci. Paris, Ser. I 337 (2003).     

t-Sets and some algebraic properties in β S and in ℓ ∈ fty(S) *

For a large class of infinite discrete semigroups, we prove that right cancellative points in β S can have arbitrary norms or sizes. More precisely, if for x∈β S, we let ||x||= min{|A| : x ∈

Liquid chromatographic-tandem mass spectrometric assay for the simultaneous quantification of Camptosar and its metabolite SN-38 in mouse plasma and tissues

A simple, rapid and sensitive LC-MS/MS bioanalytical method has been developed to simultaneously quantify Camptosar (CPT-11) and its active metabolite, SN-38, in mouse plasma and tissues. A single step protein precipitation with acetonitrile in 96-well plates was used for sample preparation. Camptothecin (CPT) was used as the internal standard. Fast separation of SN-38, CPT-11 and CPT was carried out isocratically on a C18, 2 mm x 50 mm, 5 microm HPLC column with a mobile phase containing acetonitrile and 20 mM ammonium acetate (pH 3.5) and a 2.5 min chromatographic run time. The API 4000 MS/MS system was operated in positive ionization multiple reaction monitoring mode, and the transitions for SN-38, CPT-11 and CPT were 393.4 --> 349.3, 587.6 --> 167.2 and 349.3 --> 305.3, respectively. The SN-38 and CPT-11 concentrations in samples were calculated from a standard curve of peak area ratios of the analyte to that of the internal standard using a 1/chi2 weighted linear regression. The quantitation limit of 0.5 ng/mL was achieved by using a low sample volume (100 microL) of plasma or tissue homogenates. The assay was linear over the concentration range of 0.5-500 ng/mL with acceptable precision and accuracy. The method was used for the quantification of CPT-11 and SN-38 in plasma and tissues to support a preclinical pharmacokinetics and tissue distribution study of CPT-11 in mice.     

Spectrophotometric determination of manganese by using redox reaction of tris(2,2'-bipyridine)osmium(II) with Mn7+.

This paper reports on the analytical application of the oxidation reaction of [Os(bpy)3]2+ by Mn7+ (MnO4-). The present study developed a very simple, sensitive and selective spectrophotometric method for the determination of manganese in an acidic medium. Three analytical wavelengths were employed in the UV and visible regions at 290, 315 and 480 nm. Beer's law was obeyed up to a concentration of 330 ng ml(-1) of Mn7+ at different wavelengths with regression equations 0.001 - 0.0042C(Mn), 0.001 + 0.0021C(Mn), and 0.001 - 9.34 x 10(-4)C(Mn) at 290, 315 and 480 nm, respectively. Under the optimum conditions, the achieved detection limits were 0.72, 1.37 and 3.32 ng ml(-1) at 290, 315, and 480 nm, respectively. In addition to the high sensitivity of the method (0.24 ng cm(-2) at 290 nm, 0.45 ng cm(-2) at 315 nm and 1.0 ng cm(-2) at 480 nm), it can be used for the determination of manganese in the presence of a large number of anions and cations, since it tolerates most of the potential interferents. The relative standard deviation was 0.5% (n = 11) for 90 ng ml(-1) manganese. The method was successfully applied to the determination of manganese in water from different resources.     

Zn Doping Effect on Magnetic Properties of Znx Cdl-xCr2S4 Systems by High-Temperature Series Expansions

The effect of Zn doping on the magnetic properties of CdCr2S4 systems is studied by mean field theory and high-temperature series expansion （HTSE）. The nearest neighbouring and the next-neighbouring super-exchange interactions Jl（x） and J2（x） are evaluated for the spinel system Zn, Cd1-xCr2S4 in the range 0 〈 x 〈 1. The intra-planar and the inter-planar interactions are deduced. The HTSE combined with the Padd approximant method （PA） is applied to the spinel system ZnxCdl-,Cr2S4. The magnetic phase diagram, i.e. Tc versus dilution x, is obtained. The critical exponents associated with the magnetic susceptibility 7 and the correlation length u are deduced. The obtained theoretical results are in agreement with the experimental data obtained by magnetic measurements.     

Sum rules involving coefficients of fractional parentage

Some sum rules involving the coefficients of fractional parentage are obtained. It is shown how these may be used to obtain expressions for the number of independent states in the (jⁿ)^J,T configuration.     

Synthesis,tautomeric stability,spectroscopy and computational study of a potential molecular switch of (Z)-4-(phenylamino)pent-3-en-2-one

The (Z)-4-(phenylamino) pent-3-en-2-one (PAPO) was synthesised applying carbon-based solid acid and described by experimental techniques. Calculated results reveal that its keto-amine form is more stable than its enol-imine form. A relaxed potential energy surface scan has been accomplished based on the optimised geometry of NH tautomeric form to depict the potential energy barrier related to intramolecular proton transfer. The spectroscopic results and theoretical calculations demonstrate that the intramolecular hydrogen bonding strength of PAPO is stronger than that in 4-amino-3-penten-2-one)APO(. In addition, molecular electrostatic potential, total and partial density of stats (TDOS, PDOS) and non-linear optical properties of the compound were studied using same theoretical calculations. Our calculations show that the title molecule has the potential to be used as molecular switch.     

Experimental and Theoretical Study of MTBE Adsorption from Polluted Water on GAC and PAC in Continuous Process

Methyl tertiary butyl ether (MTBE) is an organic compound thatis used to increase the gasoline octane number. At the beginning of 1980s, by discovering the undesirable effects of tetra ethyl lead usage in fuel, MTBE began to be used worldwide. But gradually the undesirable effects of MTBE on environment had been revealed. Adsorption is the most conventional and economical technology for MTBE removal from polluted water. In this research, some experiments have been done for studying the adsorption of MTBE on different solid adsorbent in continuous processes. In continuous experiments, the water polluted with known initial MTBE concentration passes through an adsorption column containing two kinds of adsorbent including granular activated carbon (GAC), powdered activated carbon (PAC). By measuring MTBE concentration in exit flow at different times the effect of different operating parameters such as temperature, pH, and flow rate have been studied and the optimum condition have been determined. The batch experimental results have been used to calculate the constant parameters of Langmuir adsorption isotherm equations. A dynamic simulation of MTBE adsorption on activated carbon in an adsorption column has been proposed. The comparison of the experimental data with the values given by the proposed model for similar operating conditions, verifies the accuracy of the proposed mathematical model.