Shed plane leaves as a source ofα-tocopherol

A natural source of -tocopherol — shed plane leaves — has been found. The dynamics of the accumulation of a-tocopherol over the vegetation period of the plant has been studied, and a method has been developed for its isolation and quantitative determination.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 372–374, May–June, 1995. Original article     

Enzyme and microbial sensors for phosphate, phenols, pesticides and peroxides

Biosensors employing a biocatalyst on a different level of integration have been developed for monitoring environmental pollution. These probes range from laboratory specimen to commercial detectors applied to analyzers. Recent developments on amperometric enzyme and microbial biosensors are presented here. A monoenzymatic bulk-type carbon electrode is described for biosensing organic hydroperoxides in aqueous solutions; peroxidase is immobilized within the electrode body and the direct electron transfer between electrode and enzyme is measured. Both, reversible and irreversible inhibitors of acetylcholinesterase have been quantified by using a kinetically controlled acetylcholine enzyme sequence electrode. The inhibitory effect of pesticides such as butoxycarboxime, dimethoate, and trichlorfon could be quantified within 6 min in molar concentrations. Different multi-enzyme electrodes have been developed for the determination of inorganic phosphate. These sensors represent examples of sequentially acting enzymes in combination with enzymatic analyte recycling. Using this type of amplification nanomolar concentrations can be measured.     

Investigations on the determination of NO2 with galvanic nitrate solid electrolyte cells

Solid electrolyte cells for detecting NO₂ with Ba(NO₃)₂ or Sr(NO₃)₂ partially replaced by -Al₂O₃ as solid electrolytes have been studied. The cell tension depends on the NO₂- as well as on the NO-concentration. Investigations of the establishment of the NO₂-NO-O₂-equilibrium by the catalytic effects of the used electrode materials Pt and Au have shown that a decomposition of NO₂ below 400°C cannot be expected.17th Communication on oxoanionic solid electrolytes and their possible applications; 16th Communication see Solid State Ionics 51:183–185 (1992)Extension of a part of the lecture of V. Brüser, S. Jakobs, H.-H. Möbius and U. Schönauer Galvanische NO₂-Sensoren mit Nitrat-Festelektrolyten given in Feldberg, 3. 6. 1993     

Surfaces with simple geodesics through a point

We study compact connected surfaces inm-dimensional Euclidean spaceE ^m (3 m 5) with a point through which every geodesic is aW-curve regarded as a curve in E^m.     

Measurement of γp→K + Λ and γp→K + Σ 0 at photon energies up to 1.47 GeV

The reactions pK ⁺ and pK ^{+ 0} have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the polarization and, for the first time, the ⁰ polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°–180°). The polarization of both and ⁰ is substantial at all energies and varies strongly with the production angle.This work is supported by the Bundesminister für Forschung und Technologie (BMFT), FK 06 BN 621 I     

Production rate and decay lifetime measurements ofBs0 mesons at LEP usingDs and? mesons

The study of the properties of inclusive production ofD _s mesons and of events in which a and a muon are present in the same jet provides two independent measurements of the probability,f _s ^w , for a heavy quark to hadronize into a strangeB orD meson. The data sample analysed corresponds to 243,000 hadronicZ ⁰ decays. The combined value of these measurements isf _s ^w =0.19±0.06±0.08. From the flight distance distributions ofD _s and of (-lepton) secondary vertices, with the lepton emitted at high transverse momentum relative to the jet axis, two values are obtained for theB _s ⁰ meson lifetime. Combining these measurements with a previous result based on the study ofD _s- events, theB _s ⁰ meson lifetime is measured to be: 0.96±0.37 ps.     

Mössbauer spectroscopy evidence for reductive loss of bromine from C60Br24 in reactions of halogenated C60 with ferrocene

Reactions of ferrocene (C₅H₅)₂Fe with halogenated fullerenes C₆₀X _n for X=F, Cl, Br andn = 15–39) yield non-stoichiometric solids with intense singlet Mössbauer spectra characteristic of Cp₂Fe₊ (where Cp=C₅H₅). The material isolated from reaction of Cp₂Fe with C₆₀Br₂₄ exhibits two different iron environments and magnetic ordering temperatures of 14 K and between 4.6 and 1.32 K. These data are seen to be consistent with loss of bromine from the fullerene and formation of ferricenium tetrahaloferrate salts.     

Anion dependence of the valence state detrapping behavior for a fused hydrocarbon bridged binuclear mixed valence iron compound and its di-oxygen sensitivity

Monocationic forms of the symmetric and asymmetric indacene bridged species [(Cp^*Fe)₂(-s-indacene)],I, and [(Cp^*Fe)₂(-as-indacene)],II, are fully detrapped and trapped, respectively, over the entire range from 1.5 K to ambient temperature as their BF ₄ ^– salts. In contrast to [II ⁺][BF ₄ ^– ], the TCNE^.– salt [II ⁺][TCNE^.–] exhibits a transition from fully trapped to a largely detrapped valence state behaviour over the increasing temperature range 100 to 300 K. Mössbauer spectra ofI suggest that while it is relatively insensitive to oxygen as a neat solid, it is strongly oxidized by O₂ in dry hexane solution. Similar studies ofII indicate essential insensitivity to O₂, both as a solid and in hexane solution.