RESONANCE-ENHANCED CARS SPECTROSCOPY OF BILIPROTEINS. INFLUENCE OF AGGREGATION and LINKER PROTEINS ON CHROMOPHORE STRUCTURE IN ALLOPHYCOCYANIN (Mastigocladus laminosus)

Abstract— Resonance-enhanced coherent anti-Stokes Raman spectra (CARS) are reported for monomers and for trimers with and without linker proteins of allophycocyanin isolated from Mastigocladus laminosus. The CARS spectrum of the monomer is independent of the presence of linker proteins and is very similar to that of phycocyanin monomers indicating that the equivalent chromophores exhibit like structures in both biliproteins. Large differences are, however, observed between the spectra of phycocyanin trimers and those of allophycocyanin trimers with or without linker proteins (L_c^8,9). The observed differences between monomer and trimer spectra are consistent with a change of the α-chromophore-protein arrangement upon aggregation without linker. If linker proteins are present in the trimer, then additional geometry changes of the β-chromophores are induced; these could relate to a transition from the 15Z- anti to 15Z- syn conformation.     

Experimental investigation of deuteron photodisintegration in the δ-resonance region

Differential cross sections for the deuteron photodisintegration process were measured for photon energies between 200 and 440 MeV using the tagged photon beam facility of the Bonn 500 MeV synchrotron. At eight angles between 18° and 145° charged particles were detected simultaneously in time-of-flight spectrometers consisting of scintillation counters. Above the resonance region the measured cross sections agree fairly well with earlier results, whereas there are larger discrepancies at low photon energies.     

Normalized fifth-order spherical aberration coefficients derived from a Gaussian trajectory on rotationally symmetrical magnetic lenses

This paper reports normalized fifth-order spherical aberration coefficients C(5s)/R derived from Gaussian trajectory for rotationally symmetrical magnetic lenses, where S/D (the polepiece gap-width/bore-diameter ratio) is in the range 0.20-2.00, and k(2) (the lens-intensity parameter) is 0.10-100. It is noted that the normalized fifth-order spherical-aberration coefficient C(5s)/R changes its sign within the given parameter ranges.     

Resonance-Enhanced CARS Spectroscopy of Biliproteins: a Comparison Between Phycoerythrocyanin and Phycocyanin of Mastigocladus laminosus

Abstract— Resonance-enhanced coherent anti-Stokes Raman (CARS) spectra are reported for trimers of phycoerthrocyanin (PEC) dissolved in H₂O and D₂O. The CARS spectra are significantly different when recorded with pump wavelength either at 585 nm or 630 nm. By comparison of the 630 nm spectra with those of phycocyanin one can conclude that there is a change in the relative location of the lowest excited states of the β84 and β155 chromophores. Upon additional illumination with 514.5 nm laser light, only the spectra recorded with 585 nm pump wavelength change. This is in accordance with earlier observations that the phycoviolobilin chromophore of the a-subunit exhibits photochromic behavior. The changes in the CARS spectra provide evidence that it is the methine bridge between rings C and D that undergoes the geometrical changes. Furthermore, it is suggested that there are different types of photoinduced rearrangements operative and that the isomeric distribution is different in H₂O and D₂O.     

Azabicycloalkenes as synthetic intermediates--synthesis of azabicyclo[X.3.0]alkane scaffolds

A general method to synthesize functionalized azabicyclo[X.3.0]alkane scaffolds 5 is reported. Key intermediates are azabicycloalkenes such as 1 and 2, which are acylated with unsaturated carboxylic acids and subsequently submitted to tandem olefin metathesis. The resulting bicyclic heterocycles are versatile intermediates for different dipeptide mimetics and can be used as intermediates for natural products with indolizidine scaffolds or analogues thereof. [reaction: see text].     

Dibrommethylsulfoniumsalze – Darstellung und Kristallstruktur [1]

Dibromomethylsulfoniumsalts — Preparation and Crystal Structure The salts CH₃SBrA^? (A^? = SbCl, AsF) were prepared by various routes and characterized by their Ramanspectra. CH₃SBrAsF crystallized in the monoclinic space group P2₁/c with a = 770,5(4) pm, b = 942,4(12) pm, c = 1329,3(14) pm, β = 100,28(6)°, Z = 4. Distances and bond angles in the cation are as expected.     

Bicriterion scheduling in the two-machine flowshop

Bicriterion scheduling problems have attracted the attention of many researchers, especially in the past decade. Although more than fifty papers have been published on this topic, most studies done so far focus only on a single machine. In this paper, we extend the development to the two-machine case and present algorithms for the bicriterion of minimising makespan and number of tardy jobs and of makespan and total tardiness. Computational results are also presented.     

Beiträge zur Chemie der Schwefelhalogenide. 16. Dimethyliodsulfonium(IV)-Salze

Contributions to the Chemistry of Sulfur Halides. 16. Dimethyliodosulfonium(IV) Salts Some preparative methods of iodosulfonium(IV) salts, (CH₃)₂SI⁺AsF₆^? and (CH₃)₂SI⁺SbCl₆^?, are reported. These salts are stable up to ?20°C and they are characterized by Raman and n.m.r. spectroscopy.     

Anwendung der Reaktions-Radio-Gas-Chromatographie zur Untersuchung der Biogenese von Aromastoffen

Zusammenfassung Die Reaktions-Radio-Gas-Chromatographie erlaubt in Verbindung mit der chemischen Ausscheidungsanalyse die Identifizierung von z.B.¹⁴C-markierten Estern, S?uren, Alkoholen bzw. Carbonylverbindungen im Zusammenhang mit Untersuchungen über die Biogenese von Aromastoffen. Der Einsatz von Trennkapillaren wird diskutiert.

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Application of reaction radio-gas-chromatography to the investigation of the biogenesis of flavours

Summary Reaction radio-gas-chromatography, combined with chemical elimination analysis, makes possible the identification of e.g.¹⁴C-labelled esters, acids, alcohols or carbonyl compounds during investigations of the biogenesis of flavours. The use of capillary columns is discussed.