Local Criteria for Non-Embeddability of Levi-Flat Manifolds

We give local criteria for smooth non-embeddability of Levi-flat manifolds. For this purpose, we pose an analogue of Ueda theory on the neighborhood structure of hypersurfaces in complex manifolds with topologically trivial normal bundles.     

Analyzing powers and cross sections in elastic p-d scattering at 65 MeV

Analyzing powers and differential cross sections for $\text{p}\text{-}\text{d}$ elastic scattering have been measured at 64.8 MeV. The angular distributions cover center-of-mass angles between 8° and 169°. The relative uncertainties of the analyzing power measurement are typically ± 0.005 at c.m. angles less than 80° and are in general ± 0.015 at the remaining angles. The absolute scale of the analyzing power measurement has an uncertainty of ± 0.013. The data are compared with three-body calculations based on the Faddeev theory. In contrast with the differential cross sections, the analyzing powers could not be reproduced without the D-wave nucleon-nucleon interactions.     

Angular correlation experiments in the reactions 2H(α, nα)p and 2H(α, pα)n and comparison with the Faddeev theory and the resonating group method

At the Hamburg Isochronous Cyclotron angular correlation experiments were carried out in the reactions ²H(α, nα)p and ²H(α, pα)n, in order to determine the tensor polarization of the ground-state resonances ${}^5\text{Li}\text{(}\text{3}\text{2}{}^{\mathrm{?}}\text{)}$ and ${}^5\text{He}\text{(}\text{3}\text{2}{}^{\mathrm{?}}\text{)}$, respectively. We find that the observables for the two mirror reactions ${}^2\text{H}\text{(α,}\text{n}\text{)}{}^5\text{Li}\text{and}{}^2\text{H}\text{(α,}\text{p}\text{)}{}^5\text{He}$ are charge-dependent. This result is interpreted as evidence for a violation of charge symmetry.In the whole phase-space region absolute break-up cross sections are generally well reproduced by the Faddeev theory. On the other hand, we find that the resonating group method which has up to now been mainly applied to two-body reactions can also provide valuable information for break-up reactions. The predictions of Hackenbroich, Schütte and coworkers are in quite good agreement with the measured tensor polarization of ⁵He and ⁵Li and the corresponding angular correlation functions.     

Fargosides A-E, triterpenoid saponins from Holboellia fargesii

Five new triterpenoid saponins, fargosides A, B, C, D, and E, were isolated from the roots of Holboellia fargesii. The structures of fargosides A-E were elucidated on the basis of chemical and physicochemical evidence and found to be 3beta,20alpha-dihydroxy-29-norolean-12-en-28-oic acid 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (1), 3beta,20alpha,24-trihydroxy-29-norolean-12-en-28-oic acid 23-O-beta-D-fucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-glucopyranoside (2), 3beta,23-dihydroxy-30-norolean-2,20(29)-dien-28-oic acid 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-glucopyranosyluronic acid-(1-->3)]-alpha-L-arabinopyranoside (3), 3beta,23-dihydroxy-30-norolean-12,20(29)-dien-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (4), and 3beta,23-dihydroxy-olean-12-en-28-oic acid 3-O-methyl beta-D-glucopyranosyluronate-(1-->3)-alpha-L-arabinopyranoside (5), respectively.     

AxBAx‐Type Block–Graft Polymers with Soft Methacrylate Middle Segments and Hard Styrene Outer Grafts: Synthesis,Morphology, and Mechanical Properties

Novel copolymers with controlled architectures can function as new building blocks for well‐defined nanostructures on the basis of microphase separation, unlike conventional ABA triblock copolymers. A series of well‐defined A_xBA_x‐type block–graft copolymers consisting of soft middle segments (dodecyl methacrylate (DMA)) and hard outer graft chains (styrene (St)) were synthesized by ruthenium‐catalyzed living radical block and graft polymerization. NMR spectroscopy and size‐exclusion chromatography combined with multiangle laser light scattering confirmed the well‐defined structure of the A_xBA_x block–graft copolymers with backbones and graft chains of controlled lengths. Transmission electron microscopy and transmission electron microtomography revealed a series of morphologies for the copolymers. Morphological changes were observed from PSt “honeycomb” cylinders to lamellae and poly(DMA) cylinders with increasing PSt‐graft content, whereby the phase diagram was shifted significantly to lower volume fractions of the larger‐number component (St) relative to those of the corresponding ABA triblock copolymers. More specifically, poly(DMA) cylinders were observed even before the St content reached 50 wt %. The A_xBA_x and ABA copolymers with 17–30 wt % of St exhibited characteristics of a thermoplastic elastomer with tensile strengths of 1–6 MPa and elongations at break of 70–300 %. These mechanical properties can be related well to the microphase structures of the A_xBA_x and ABA copolymers.     

PHOTO-EXCITED TRIPLET STATE OF DIMERIC CHLOROPHYLL a IN 3-METHYLPENTANE RIGID MATRIX AT 77 K STUDIED BY FLASH PHOTOLYSIS

Abstract— Flash photolysis studies of dimeric and monomeric chlorophyll a were carried out at 77 K. The triplet-triplet absorption spectrum of the dimeric chlorophyll a in 3-methylpentane at 77 K is interpreted as a sum of the spectra of chlorophyll a in the ground and triplet states. The dimeric chlorophyll a in the triplet state is considered to have the half-excited structure at 77 K without photodisaggregation owing to high viscosity of the solvent.     

Nigramides A-S, dimeric amide alkaloids from the roots of Piper nigrum

[structure: see text] Fifteen novel dimeric amide alkaloids possessing a cyclohexene ring, nigramides A-O (1-15), as well as four novel dimeric amide alkaloids possessing a cyclobutane ring, nigramides P-S (17-20), have been isolated from the roots of Piper nigrum. Their structures were elucidated on the basis of their spectroscopic data. The biosynthestic hypothesis of nigramides A-O (1-15) was proposed by an intermolecular Diels-Alder reaction from the corresponding monomeric amides. On the basis of this biosynthetic hypothesis, the first study of the thermal and Lewis acid mediated Diels-Alder reactions of piperine in different organic solvents and under solventless conditions is also described.     

Neutron activation analysis of ivory of African elephants

Instrumental neutron activation analysis was applied to 61 ivory samples of which origin countries are known. 12 elements such as Br, Ca, Cl, Co, Cs, Fe, Mg, Mn, Na, Sc, Sr and Zn, were determined in all samples. The factor score of each sample was calculated for each factor by making use of principal component analysis in order to determine their origins. The results were compared with those by stable isotope analysis (¹³C and¹⁵N).