Histo-cytochemistry and scanning electron microscopy of lavender glandular trichomes following conventional and microwave-assisted hydrodistillation of essential oils: a comparative study

The conventional hydrodistillation method (HD) has been compared with three different variants of the microwave-assisted hydrodistillation technique (MADH), on Lavandula anguslifolia flowers, both in terms of oil yield and effects on the glandular trichome morpho-structure. The amount and composition of essential oil extracted in 4 h by HD was similar to that obtained in only 20 min by MADH and even lower than that extracted with a steam variant (MASD) of MADH itself. Histo-cytochemical investigations and scanning electron microscopy showed that glandular trichome, after 4 h of HD, appeared swollen, with a deeply wrinkled surface and empty of essential oil, however maintaining the integrity of their cuticle. Many oil droplets were stuck to the outside of the trichome cuticle, sometimes arranged in large aggregates. After 20 min of MADH or MASD, trichomes appeared empty as well, but also particularly disrupted, or at least with holes in their head cuticle. Oil droplets were present outside the glands and in the inter-rib regions of the flower calyx, except in the case of MASD. After this extraction method, neither oil droplets nor other lipid staining were present in the samples, confirming the effectiveness of this particular MADH technique. These investigations suggest that the rapidity of MADH and MASD in extracting essential oil is mainly due to the collapse of trichome structure and the consequent direct release of its content, without which it has to slowly permeate through membranes and cuticle, as in the case of HD. Copyrigh

Observation of the muon inner bremsstrahlung at LEP1

Muon bremsstrahlung photons converted in front of the DELPHI main tracker (TPC) in dimuon events at LEP1 were studied in two photon kinematic ranges: 0.2<E γ ≤1 GeV and transverse momentum with respect to the parent muon p T <40 MeV/c, and 1<E γ ≤10 GeV and p T <80 MeV/c. A good agreement of the observed photon rate with predictions from QED for the muon inner bremsstrahlung was found, contrary to the anomalous soft photon excess that has been observed recently in hadronic Z 0 decays. The obtained ratios of the observed signal to the predicted level of the muon bremsstrahlung are 1.06±0.12±0.07 in the photon energy range 0.2<E γ ≤1 GeV and 1.04±0.09±0.12 in the photon energy range 1<E γ ≤10 GeV. The bremsstrahlung dead cone is observed for the first time in the direct photon production at LEP

Search for one large extra dimension with the DELPHI detector at LEP

Single photons detected by the DELPHI experiment at LEP2 in the years 1997-2000 are reanalysed to investigate the existence of a single extra dimension in a modified ADD scenario with slightly warped large extra dimensions. The data collected at centre-of-mass energies between 180 and 209 GeV for an integrated luminosity of similar to 650 pb(-1) agree with the predictions of the Standard Model and allow a limit to be set on graviton emission in one large extra dimension. The limit obtained on the fundamental mass scale M-D is 1.69 TeV/c(2) at 95% CL, with an expected limit of 1.71 TeV/c(2)

Study of triple-gauge-boson couplings ZZZ, ZZgamma and Zgamma gamma LEP.

Neutral triple-gauge-boson couplings ZZZ, ZZγ and Zγγ have been studied with the DELPHI detector using data at energies between 183 and 208 GeV. Limits are derived on these couplings from an analysis of the reactions e+e-→Zγ, using data from the final states γff̄, with f=q or ν, from e+e-→ZZ, using data from the four-fermion final states qq̄qq̄, qq̄μ+μ-, qq̄e+e-, qq̄νν̄, μ+μ-νν̄ and e+e-νν̄, and from e+e-→Zγ*, in which the final state γ is off mass-shell, using data from the four-fermion final states qq̄e+e- and qq̄μ+μ-. No evidence for the presence of such couplings is observed, in agreement with the predictions of the Standard Model