2,775 research outputs found

    The preparation, identification and properties of chlorophyll derivatives

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    In the investigation of 10-hydroxy chlorophylls a and b novel techniques included modification of chromatography and the use of fully-deuterated compounds isolated from fully-deuterated autotropic algae to determine the molecular structure of the chlorophylls

    Dreamy Swanee Lullaby

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    With Ukulele arrangement. Contains advertisements and/or short musical examples of pieces being sold by publisher.https://digitalcommons.library.umaine.edu/mmb-vp/6987/thumbnail.jp

    Reaction of Aromatic Amines with Epihalohydrins

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    Published procedures for the reaction of primary aromatic amines with epihalohydrins to give 1:1 addition compounds are not generally applicable, and we have found that they frequently lead to impure products. The reactions were investigated in water, alcohol and bromobenzene solutions. A number of techniques were used to follow the reaction. Infrared spectroscopy gave qualitative data since significant changes occur in the 2.5 μ - 3.0 μ and the 10 μ - 11 μ regions of the spectrum. Thin layer chromatography made it possible to detect the formation of by-products and to determine the purity of the addition compounds. The best quantitative measure of the rate of the reaction was obtained by means of an oxirane titration with HBr. The reaction of epichlorohydrin with p-anisidine, p-toluidine and aniline in bromobenzenc solution exhibited an induction period believed to be due to the catalytic effect of HCI split out from the addition compound by unreacted amine

    Synthesis of N-Substituted Diamino-Propanols and their Physiological Effects

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    The p-toluiclinc-epichlorohydrin 1:1 addition compound has been reacted with pipericline, pyrrolicline, and morpholine to give disubstitutecl 2-propanols. 1-(p-Toluiclino)-3-pyrrolidino-2-propanol was fed to male rats and organ and body weights measured. The data do not permit us to evaluate adequately the physiological effects of the compound, but differences were observed in the size of the heart, kidneys, and thymus of the test animals

    Interpretation of Nuclear Quadrupole Resonance Spectra in Doped La2_2CuO4_4

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    The nuclear quadrupole resonance (NQR) spectrum of strontium doped La2_2CuO4_4 surprisingly resembles the NQR spectrum of La2_2CuO4_4 doped with excess oxygen, both spectra being dominated by a main peak and one principal satellite peak at similar frequencies. Using first-principles cluster calculations this is investigated here by calculating the electric field gradient (EFG) at the central copper site of the cluster after replacing a lanthanum atom in the cluster with a strontium atom or adding an interstitial oxygen to the cluster. In each case the EFG was increased by approximately 10 % leading unexpectedly to the explanation that the NQR spectra are only accidentally similar and the origins are quite different. Additionally the widths of the peaks in the NQR spectra are explained by the different EFG of copper centres remote from the impurity. A model, based on holes moving rapidly across the planar oxygen atoms, is proposed to explain the observed increase in frequency of both the main and satellite peaks in the NQR spectrum as the doping concentration is increased

    Exclusive Decuplet-Baryon Pair Production in Two-Photon Collisions

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    This work extends our previous studies of two-photon annihilation into baryon-antibaryon pairs from spin-1/2 octet to spin-3/2 decuplet baryons. Our approach is based on perturbative QCD and treats baryons as quark-diquark systems. Using the same model parameters as in our previous work, supplemented by QCD sum-rule results for decuplet baryon wave functions, we are able to give absolute predictions for decuplet baryon cross sections without introducing new parameters. We find that the Δ++\Delta^{++} cross section is of the same order of magnitude as the proton cross section, well within experimental bounds.Comment: 14 pages, 2 figure

    Variation with mass of \boldmath{B(E3; 0_1^+ \to 3_1^-)} transition rates in A=124134A=124-134 even-mass xenon nuclei

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    B(E3;01+31)B(E3; 0_1^+ \to 3_1^-) transition matrix elements have been measured for even-mass 124134^{124-134}Xe nuclei using sub-barrier Coulomb excitation in inverse kinematics. The trends in energy E(3)E(3^-) and B(E3;01+31)B(E3; 0_1^+ \to 3_1^-) excitation strengths are well reproduced using phenomenological models based on a strong coupling picture with a soft quadrupole mode and an increasing occupation of the intruder h11/2h_{11/2} orbital.Comment: 5 pages, 4 figures, PRC in pres

    Detection by NMR of a "local spin-gap" in quenched CsC60

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    We present a 13C and 133Cs NMR investigation of the CsC60 cubic quenched phase. Previous ESR measurements suggest that this phase is metallic, but NMR reveals contrasting electronic behavior on the local scale. The 13C spin-lattice relaxation time (T1) exhibits a typical metallic behavior down to 50 K, but indicates that a partial spin-gap opens for T<50 K. Unexpectedly, 133Cs NMR shows that there are two inequivalent Cs sites. For one of these sites, the NMR shift and (T1T)^{-1} follow an activated law, confirming the existence of a spin-gap. We ascribe this spin-gap to the occurrence of localized spin-singlets on a small fraction of the C60 molecules.Comment: 4 figure

    Genome-wide screening for DNA variants associated with reading and language traits

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    This research was funded by: Max Planck Society, the University of St Andrews - Grant Number: 018696, US National Institutes of Health - Grant Number: P50 HD027802, Wellcome Trust - Grant Number: 090532/Z/09/Z, and Medical Research Council Hub Grant Grant Number: G0900747 91070Reading and language abilities are heritable traits that are likely to share some genetic influences with each other. To identify pleiotropic genetic variants affecting these traits, we first performed a genome‐wide association scan (GWAS) meta‐analysis using three richly characterized datasets comprising individuals with histories of reading or language problems, and their siblings. GWAS was performed in a total of 1862 participants using the first principal component computed from several quantitative measures of reading‐ and language‐related abilities, both before and after adjustment for performance IQ. We identified novel suggestive associations at the SNPs rs59197085 and rs5995177 (uncorrected P ≈ 10–7 for each SNP), located respectively at the CCDC136/FLNC and RBFOX2 genes. Each of these SNPs then showed evidence for effects across multiple reading and language traits in univariate association testing against the individual traits. FLNC encodes a structural protein involved in cytoskeleton remodelling, while RBFOX2 is an important regulator of alternative splicing in neurons. The CCDC136/FLNC locus showed association with a comparable reading/language measure in an independent sample of 6434 participants from the general population, although involving distinct alleles of the associated SNP. Our datasets will form an important part of on‐going international efforts to identify genes contributing to reading and language skills.Publisher PDFPeer reviewe

    Phase diagram of YBa2_2Cu3_3O7y_{7-y} at T<<Tc_c based on Cu(2) transverse nuclear relaxation

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    Two maxima in transverse relaxation rate of Cu(2) nuclei in YBa2_2Cu3_3O7y_{7-y} are observed, at T = 35 K and T = 47 K. Comparison of the 63^{63}Cu(2) and 65^{65}Cu(2) rates at T = 47 K indicates the magnetic character of relaxation. The enhancement at T = 47 K of fluctuating local magnetic fields perpendicular to the CuO2_2 planes is connected with the critical fluctuations of orbital currents. Maximum at T = 35 K is connected with the appearance of inhomogeneous supeconducting phase. Together with data published to date, our experimental results allow to suggest a qualitatively new phase diagram of the superconducting phase.Comment: 4 LaTEX pages + 3 figures in *.ps forma
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