Protogenkwanin,a new flavonoid from equisetum arvense L

From the fertile sprouts of Equisetum arvense L. have been isolated protogenkwanin 4'-glucoside and gossypitrin. The structure of protogenkwanin as 5-hydroxy-2-(1,4-dlhydroxy-2,5-cyclohexadienyl)-7-methoxy-4-chromenon is proved on the basis of chemical and physical evidence. It is demonstrated that articulatin a thiamine decomposing substance, from E. arvense, is identical with the known flavonol glycoside gossypitrin (= gossypetin-7-glucoside). The synthesis of 2,5-dihydroxy-2-(4 hydroxyphenyl)-7-methoxy-4-chromanon is reported.     

De Rham Cohomology and Hodge Decomposition For Quantum Groups

Let be one of the N²-dimensionalbicovariant first order differential calculi for the quantumgroups GL_q(N), SL_q(N), SO_q(N), or Sp_q(N), where q is a transcendentalcomplex number and z is a regular parameter. It is shown thatthe de Rham cohomology of Woronowicz' external algebra coincides with the de Rham cohomologiesof its left-coinvariant, its right-coinvariant and its (two-sided)coinvariant subcomplexes. In the cases GL_q(N) and SL_q(N) thecohomology ring is isomorphic to the coinvariant external algebra and to the vector space of harmonic forms. We prove a Hodge decomposition theorem in thesecases. The main technical tool is the spectral decompositionof the quantum Laplace-Beltrami operator. 2000 MathematicalSubject Classification: 46L87, 58A12, 81R50.     

Oxidized polyethylenimine

Polyethylenimine (PEI) has been oxidized with aqueous hydrogen peroxide to yield a hygroscopic, water-soluble, slightly basic, yellow polymeric solid (OPEI) containing about 25% oxygen. Some chain degradation accompanies oxidation. The nature of the product varies somewhat with preparative conditions. OPEI, in the presence of strong alkali, reduces silver salts and peptizes a portion of the silver. By use of infrared, ultraviolet, and proton magnetic resonance spectroscopy together with qualitative testing, OPEI has been found to contain carboxyl groups, unoxidized primary amine groups, tertiary amine oxide, small amounts of aldehyde and nitrone groups, and a considerable amount of secondary amide. The probable reaction sequence is: PEI → dialkylhydroxylamine → nitrone → oxazirane → rearranged product. Oxazirane groups appear to be absent, as well as oxime, nitro, nitrite, and nitrate. The groups which reduce silver salts are not known with certainty but are probably of the hydroxylamine type. The carboxyl content of OPEI is associated with the lower molecular weight species which are present.     

Traveling–stripe forcing of oblique rolls in anisotropic systems

The effects of a traveling, spatially periodic forcing are investigated in a system with axial anisotropy, where oblique stripe patterns occur at threshold in the unforced case and where the forcing wavenumber and the wavenumber of stripes are close to a 2:1 resonance. The forcing induces an interaction between the two degenerate oblique stripe orientations and for larger forcing amplitudes rectangular patterns are induced, which are dragged in phase by the forcing. With increasing forcing velocity a transition from a locked rectangular pattern to an unlocked superposition of a rectangular and oblique stripe pattern takes place. In this transition regime, especially when the ratio between the wavenumber of the forcing and that of the pattern deviates from the 2:1 ratio, surprisingly stable or long living complex patterns, such as zig–zag patterns and patterns including domain walls are found. Even more surprising is the observation, that such coherent structures propagate faster than the stripe forcing.     

On the production of flat electron bunches for laser wakefield acceleration

We suggest a novel method for the injection of electrons into the acceleration phase of particle accelerators, producing low-emittance beams appropriate even for the demanding high-energy linear collider specifications. We discuss the injection mechanism into the acceleration phase of the wakefield in a plasma behind a high-intensity laser pulse, which takes advantage of the laser polarization and focusing. The scheme uses the structurally stable regime of transverse wakewave breaking, when the electron trajectory self-intersection leads to the formation of a flat electron bunch. As shown in three-dimensional particle-in-cell simulations of the interaction of a laser pulse elongated in the transverse direction with an underdense plasma, the electrons injected via the transverse wakewave breaking and accelerated by the wakewave perform betatron oscillations with different amplitudes and frequencies along the two transverse coordinates. The polarization and focusing geometry lead to a way to produce relativistic electron bunches with an asymmetric emittance (flat beam). An approach for generating flat laser-accelerated ion beams is briefly discussed. The text was submitted by the authors in English.     

Messung der Zirkularpolarisation der 478 keV-Gammaquanten aus der Reaktion Li6(d,p)Li7 mit 2 MeV-Deuteronen

The circular polarizationP _γ of 478 keVγ quanta from the reaction Li⁶(d, pγ) Li⁷ with 2 MeV deuterons was measured by forward Compton scattering from magnetized iron. The protons were observed at 25° lab angle. The fast neutron background in theγ detector was suppressed by pulse shape discrimination. The resultP _γ=+ 0.022 ± 0.17 with the Basel sign convention confines the ratio of the reduced widthsΘ _± for the capture of the neutron withj=1±1/2 to the regions ?2.36≦Θ ₊/Θ _?≦?0.74 or ?0.06≦Θ ₊/Θ _?≦+0.61.     

Lateral-deformation gage for rock-mechanics testing

Lateral-deformation measurements are important in rock-mechanics testing, both for providing material-behavior information and for acting as a control variable in servo-controlled experiments designed to obtain post-failure stress-strain curves. A gage for making these measurements must be compact, have a large linear range, and for tests on anisotropic rock, be able to monitor a discrete sample diameter. A gage which employs a strain-gaged sensing disk is described which meets all of these requirements.     

Solid phase vs. solution phase differential behavior: Formation of a salicylate structure from a malondialdehyde moiety

Treatment of 2, solid supported synthetic equivalent of 3-formylchromone (4), and ethyl acetoacetate affords the salicylate structure 8 instead of the previously reported isophtalate 7. This is the first formation of a salicylate by a double carbonyl condensation of a malondialdehyde moiety ever reported.