First efficient uncharged reactivators for the dephosphylation of poisoned human acetylcholinesterase

Nerve agents are highly toxic organophosphorus compounds with strong inhibition potency against acetylcholinesterase (AChE). Herein, we describe two first extremely promising uncharged reactivators for poisoned human AChE with a superior or similar in vitro ability to reactivate the enzyme as compared to that of HI-6, obidoxime, TMB-4 and HL?-7.     

A novel and unusually long-lived chemiluminophore based on the 7-hydroxycoumarin scaffold

Synthesis and chemiluminescent properties of a new 1,2-dioxetane chemiluminophore bearing a 7-hydroxycoumarin moiety are presented. The 1,2-dioxetane decomposition ended up with strong and long-lived emission of light. This new structure opens way to the development of a new generation of bright chemiluminescent bio-probes.     

About a possible constancy of the total cross-section of the e+e− annihilation into hadrons

We show how a series of vector mesons can give a constant total cross-section in agreement with the experimental results up to 5 GeV. We discuss also the ratios n_π^°/n_π±,n_K/n_π and the breakdown of scaling in the inclusive spectra.     

Critical behaviour of a uniaxial ferromagnet,ErCl3·6H2O with predominant dipolar interactions

The parallel magnetic susceptibility χ of a uniaxial ferromagnet ErCl₃·6H₂O has been measured between 0.3 and 4.2K and specially near T_c = 0.353 K. The predominant contribution to the Curie-Weiss temperature is due to the dipolar interactions. χ is proportional to ?^?γ with $\text{? =}\text{T}\text{T}{}_{\mathrm{c}}\text{?1}$ in the range 10^?3 < ? < 5 × 10^?2. The γ value, γ = 1.01 ±0.03 is consistent with the theoretical prediction for a uniaxial dipolar ferromagnet.     

Cross-sections for deuteron photo-disintegration from 139 to 832 MeV

The cross-sections for deuteron photo-disintegration have been measured at nine c.m. angles from 37 to 143 degrees. The minimum and maximum photon energies have been 139 and 832 MeV respectively. The results are in agreement with earlier data above 300 MeV, but are significantly larger below 200 MeV, the discrepancies being up to 50% at the lowest energies measured.     

Anomalous effects ine + e − annihilation into boson pairs II.e + e −→ZZ, γZ, γγ

In application of the general procedure defined in I, we analyze various kinds of anomalous effects which could appear either in the leptonic or in the bosonic sector of the reactionse ⁺ e ^?→ZZ, γZ and γγ: excited electron, excited vector boson or isoscalar partner, anamalous three-neutral boson couplings, residual contact terms involving transverse or longitudinalZ-components. Results are given in view of SLC, LEP and future linear colliders.     

Crystal growth,structure, electron paramagnetic resonance and magnetic properties of (NH4)2V3O8

A method to grow single crystals of ammonium vanadate (IV, V) (NH₄)₂V₃O₈ has been devised. The crystal structure is tetragonal P4bm; residual factor is R = 0.030. Cell parameters are $\text{a = 8.891 ± 0.004}\text{A}\text{?}$ and $\text{c = 5.582 + 0.002}\text{A}\text{?}$. The V⁵⁺ atom lies at the center of a triangular pyramide (VO₄ tetrahedron) while the V⁴⁺ atom is on A 4-fold rotation axis at the center of a square-based pyramide VO₅ whose symmetry point group is almost C_4v with the short V = O bond lying along the 4-fold axis parallel to the c edge of the tetragonal cell. Crystals are thin platlets with (001) cleavage planes. The platlets have very often a square or rectangular shape limited by {100} or {110} planes. Each single crystal was not large enough to record a good e.p.r. spectrum, but by sticking on the same quartz plate a score of them it was possible to gather enough crystals so to record correct spectra and by orienting the plate to obtain resonance lines separately for g_∥ = 1.9263 et g_τ = 1.9755. Measurements at 283 K on powder samples gave times for spin-spin relaxation T₂ = 0.4 × 10^?7s and for spin-lattice relaxation T₁ = 1.6 × 10^?7s. The magnetic structure is characterized by an exchange narrowing ω_e = 3 × 10¹⁰rad/s which corresponds to a transition temperature of about 0.5 K. Static susceptibility measurements at high magnetic field show a paramagnetic behaviour with an antiferromagnetic interaction which is interpreted in the magnetic space group P_2c4bm as the interaction between V⁴⁺ ions from consecutive planes parallel to (001).     

Possible excitation of new C=+1 states via 2 photons e+e− annihilation

We suggest to look at the reactions e⁺e^?→χ→ hadrons which can occur via 2γ annihilation around 3.4 and 3.5 GeV with a cross-section of the order of a few 10^?34cm² MeV and where the χ could decay mainly into ππη_c and ηη_c.     

1H and 13C NMR study of the effects exerted by an oxirane ring in the epoxybicyclo-[2.2.2]octane series

The ¹H and ¹³C NMR spectra of 2,3-disubstituted exo-5,6- and endo-5,6-bicyclo[2.2.2]octanes, and the corresponding alkanes, have been investigated to determine the effects exerted by an oxirane ring. The ¹H NMR study showed that the anti protons, H-7a and H-8a, are significantly shielded and the syn protons, H-7s and H-8s, are deshielded, although to a smaller extent, by the exo-oxirane. An endo-oxirane has practically no effect on the same protons. The stereochemistry of epoxybicyclo[2.2.2]octanes is, thus, easily deduced from ¹H NMR data. The ¹³C NMR study of the epoxy compounds provided an estimate of the value of α, β, γ syn and γ anti effects (to the epoxide oxygen) of an oxirane ring. In these rigid bicyclic molecules, of known geometry, the γ syn and the γ anti effects are of the same value, even though the dihedral angles are very different (0° and 120°).