197 research outputs found

    First evidence of the existence of Common fumana (Fumana procumbens) in north Hesse

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    Der Fund liegt im geplanten Naturschutzgebiet „Scheid bei Volkmarsen“ am Nordwestrand des Verbreitungsgebietes der Art. Die Pflanzen wachsen über Muschelkalk im Halbtrockenrasen.The discovery in the projected nature reserve „Scheid near Volksmarsen“ (north-west of Kassel) was made on the north-western edge of the distribution area of the species. The plants grow on shell limestone in mesoxerophytic meadows

    Flügel

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    Ansatz meines Entwurfes war die Eigenschaft des Carbonbetons, mit ihm sehr dünne, stabile und korrosionsbeständige Konstruktionen herstellen zu können. Da ich unter anderem an der Leistungsgrenze von Betonkonstruktionen im bildhauerischen Bereich arbeite und Federn und Flügel eine sehr dünne, leistungsfähige und natürliche Einheit bilden, habe ich dies als mein Thema gewähl

    Das Ende der Ära Adenauer

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    Molecular and crystal structure of cyanoformamide

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    C2H2N20, M = 70.051; Pnma; a = 8.519(6), b = 5.427(4), c=7.235(5)A; Z=4; D x= 1.391g·cm -3 ; V=334.49A 3; (MoKa)=0.71069A; F(000) = 144. The structure was solved with direct methods and refined by least-squares analysis to an R = 0.059 including 363 observed reflections. The molecule lies on the mirror plane and must therefore be completely planar. By two intermolecular hydrogen bridges towards the oxygen and the nitrogen atom of the carbonyl and the nitrile group respectively, neighbouring molecules of the same layer are bound together

    Alkylidenephosphines and diphosphetanes

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    In studies of the reactivity and thermal stability of various alkylidenephos-phines prepared from benzophenone and organylbis(trimethylsilyl)phosphines via a NaOH-catalyzed elimination of hexamethyldisiloxane (eq. la), detailed analyses of nmr-spectra and x-ray structure determinations prove the methyl derivative la to dimerize to an 1,3-diphosphetane (2a), whereas from the iso-propyl compound 1b the 1,2-diphosphetane 2b is obtained [1]. This observation confirms our hypothesis that the formation of 1,2- or 1,3-diphosphetanes is determined by the steric requirements of the substituent at phosphorus

    EXPRESSION OF A FUNCTIONAL CHIMERIC lg-MHC CLASS II PROTEIN

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    composed of the a- and ß-chains of the MHC class I1 I-E molecule fused to antibody V regions derived from anti-human CD4 mAb MT310. Expression vectors were constructed containing the functional, rearranged gene segments coding for the V region domains of the antibody H and L chains in place of the first domains of the complete structural genes of the I-E a- and ß-chains, respectively. Celltsr ansfected with both hybrid genes expressed a stable protein product on the cell surface. The chimeric molecule exhibited the idiotype of the antibody MT310 as shown by binding to the anti-idiotypic mAb 20-46. A protein of the anticipated molecular mass was immunoprecipitated witha nti-mouse IgG antiserum. Furthermore, human soluble CD4 did bind to thetr ansfected cell line, demonstrating that the chimeric protein possessed the binding capacity of the original mAb. Thus, the hybrid molecule retained: 1) the properties of a MHC class I1 protein with regardt o correct chain assembly and transport to the cell surface: as well as 2) the Ag binding capacity of the antibody genes used. Thgee neration of hybrid MHC class I1 molecules with highly specific, non-MHC-restricted bindingc apacities will be useful for studying MHC class 11-mediated effector functions such as selection of the T cell repertoire in thymus of transgenic mice

    Ab initio equations of state for hydrogen (H-REOS.3) and helium (He-REOS.3) and their implications for the interior of Brown Dwarfs

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    We present new equations of state (EOS) for hydrogen and helium covering a wide range of temperatures from 60 K to 107^7 K and densities from 101010^{-10} g/cm3^3 to 10310^3 g/cm3^3. They include an extended set of ab initio EOS data for the strongly correlated quantum regime with an accurate connection to data derived from other approaches for the neighboring regions. We compare linear-mixing isotherms based on our EOS tables with available real-mixture data. A first important astrophysical application of this new EOS data is the calculation of interior models for Jupiter and the comparison with recent results. Secondly, mass-radius relations are calculated for Brown Dwarfs which we compare with predictions derived from the widely used EOS of Saumon, Chabrier and van Horn. Furthermore, we calculate interior models for typical Brown Dwarfs with different masses, namely Corot-3b, Gliese-229b and Corot-15b, and the Giant Planet KOI-889b. The predictions for the central pressures and densities differ by up to 10%\% dependent on the EOS used. Our EOS tables are made available in the supplemental material of this paper.Comment: 14 pages, 19 Figures, accepted at ApJ

    1,2- and 1,3-diphosphetanes from alkylidenephosphines

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    Alkyl- or arylbis(trimethylsilyl)phosphines as well as tris(trimethylsilyl)phosphine and the corresponding arsines react with acyl chlorides to give [1-(trimethylsiloxy)alkylidene]phosphines 1 and -arsines 2; most of their 2,2-dimethylpropylidene derivatives are thermally stable at room temperature. With the same class of phosphines as starting compounds and carbon disulfide [bis(trimethylsilylsulfano)methylidene]phosphines 3 are formed, whereas [(dialkylamino)methylidene]-4 and [diarylmethylidene]phosphines 5 or the corresponding arsines 6 and 7 can be obtained from acyl amides or ketones

    Real-time use of audio-biofeedback can improve postural sway in patients with degenerative ataxia

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    Abstract Objective Cerebellar ataxia essentially includes deficient postural control. It remains unclear whether augmented sensory information might help cerebellar patients, as the cerebellum underlies processing of various sensory modalities for postural control. Here, we hypothesized that patients with cerebellar degeneration can still exploit audio‐biofeedback (ABF) of trunk acceleration as a real‐time assistive signal to compensate for deficient postural control. Methods Effects on postural sway during stance were assessed in an ABF intervention group versus a no‐ABF disease control group (23 vs. 17 cerebellar patients) in a clinico‐experimental study. A single‐session ABF paradigm of standing plus short exergaming under ABF was applied. Postural sway with eyes open and eyes closed was quantified prior to ABF, under ABF, and post ABF. Results Postural sway in the eyes closed condition was significantly reduced under ABF. Both benefit of ABF and benefit of vision correlated with the extent of postural sway at baseline, and both types of sensory benefits correlated with each other. Patients with strongest postural sway exhibited reduced postural sway also with eyes open, thus benefitting from both vision and ABF. No changes were observed in the no‐ABF control group. Interpretation Our findings provide proof‐of‐principle evidence that subjects with cerebellar degeneration are still able to integrate additional sensory modalities to compensate for deficient postural control: They can use auditory cues functionally similar to vision in the absence of vision, and additive to vision in the presence of vision (in case of pronounced postural sway). These findings might inform future assistive strategies for cerebellar ataxia

    Alkylidynephosphines : syntheses and reactivity

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    In the past, different methods have been utilized for the preparation of alkylidynephosphines. Whereas, however, small amounts of thermally instable derivatives might be obtained from reactions in the gas phase, the synthesis of phosphines which are stable under an inert atmosphere, as for instance those with a tert-butyl or a 1-adamantyl substituent at the carbon atom of the PEC group, is best started with tris (trimethylsilyl) phosphine itself or with the more reactive lithium bis (trimethylsilyl) phosphide.2 tetrahydrofuran complex. Treatment of either compound with acyl halides results in the formation of acylbis (trimethylsilyl) phosphines which, at room temperature, rearrange to the corresponding trimethylsilyl [1-(trimethylsiloxy) alkylidene] isomers. As traces of hydrogen halide accelerate the conversion of tris (trimethylsilyl) phosphine to the triacyl derivatives, the use of the lithium phosphide is strongly recommended in all cases where impure acyl halides are used. In the presence of small amounts of solid sodium hydroxide suspended in an etherial solvent, the thus prepared trimethyl[1-(trimethylsiloxy)-alkylidene]phosphines eliminate hexamethyldisiloxane to yield the required alkylidyne compounds. Running the decomposition without a solvent at a higher temperature, Regitz and coworkers were able to improve this method further
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