Meso-Tetraphenylporphyrin Dimer Derivative as a Potential Photosensitizer in Photodynamic Therapy

Abstract— Studies on the synthesis, preliminary in vivo biological activity, singlet oxygen and fluorescence yields of a di-meric porphyrin (Dl) are described. The pharmacokinetic behavior and photodynamic properties of the dimer Dl were examined in Balb/c mice bearing an MS-2 fibrosarcoma. Compound Dl shows a high selectivity for tumor localization (tumor/peritumoral tissue ratios of dye concentration ranging between ca 100 and 140 at 24 h after drug administration of 5.0-1.0 mg kg_-1 into DL-AL-dipalmitoylphosphatidylcholine liposomes). The photo-therapeutic efficiency of dimer Dl was evaluated by following the growth curves of fibrosarcoma irradiated with red light (600-700 nm) with a total dose of 400 J cm_-2, at 24 h after intravenous injection. Photodynamic therapy-treated tumors showed a significant delay in growth as compared to untreated control mice. The results obtained suggest that the porphyrin dimer Dl may be a promising candidate for further use in PDT experiments.     

Darstellung und Kristallstruktur von Niob-Tantal-Nitridphasen (Nb,Ta)N∼1

Preparation and Crystal Structures of Niobium-Tantalum-Nitride Phases (Nb, Ta)N_～1 Ta? Nb alloys with graduated composition are nitrided with NH₃ at 1100–1450°C. The mononitrides formed are investigated by X-ray diffraction. Their nitrogen content is evaluated by chemical analysis. Seven Ta? Nb nitride phases are observed. Depending on the temperature, the phases appear in a strictly defined sequence along the variation of the Ta:Nb relation. Corresponding to this sequence, the density (formula volume) of this nitride phases varies.     

Synthesis and characterization of a helical step‐ladder polyarylene

A helical step‐ladder polyarylene incorporating chiral (R)‐2,2′‐dioctoxy‐1,1′‐binaphthyl units was synthesized for the first time. The first step involved the preparation of a precursor poly(arylene ketone) via a palladium‐mediated Suzuki‐type cross‐coupling reaction with the aid of microwave heating. Two polymer‐analog reaction steps, the reduction of the keto groups to tertiary alcohol functionalities and subsequent intramolecular Friedel–Crafts cyclization, gave a step‐ladder polymer ( 6 ) in good yields with reasonable mean average molecular weights greater than 13,000. The regioselective cyclization pattern in the α position of the naphthalene core was confirmed by a comparison of the NMR data of the polymer with those of the corresponding model ladder oligomers, 12 and 13 , and also a single‐crystal structure of 13 . The optical spectra of the oligomers and polymers indicated that there was little electronic interaction across the binaphthyl units. The circular dichroism spectrum of 6 exhibited a strong bisignate Cotton effect in the π–π* absorption region of the planar chromophores, which reflected the strong exciton coupling within the helical polymer chain. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5533–5545, 2006     

Über Systeme hyperkomplexer Zahlen

Ohne Zusammenfassung     

Über die Dichte der Summe zweier Mengen. deren eine von positiver Dichte ist

Ohne Zusammenfassung     

Characterization of a SiC/SiC composite by X-ray diffraction, atomic force microscopy and positron spectroscopies

A SiC/SiC composite is characterized by X-ray diffraction, atomic force microscopy and various positron spectroscopies (slow positron implantation, positron lifetime and re-emission). It is found that besides its main constituent 3C-SiC the composite still must contain some graphite. In order to better interpret the experimental findings of the composite, a pyrolytic graphite sample was also investigated by slow positron implantation and positron lifetime spectroscopies. In addition, theoretical calculations of positron properties of graphite are presented.     

Novel inorganic ring systems. XL: A dimeric cycloalumadisiladiazane

The first cycloalumadisiladiazane (F1) has been prepared by reacting dilithiated 1,2-bis(methylamino)tetramethyldisilane with AlCl₃ at ?80°C. The compound has been characterized by elemental analysis,¹H NMR, mass spectroscopy and single crystal X-ray diffraction. Crystals belong to the orthorhombic space group Pbca witha=8.3506 (4),b=16.1056 (8),c=19.1186 (6) Å,Z=4 andd _calc=1.22 g/cm³. The structure was refined to a conventionalR value of 0.030 using 1 810 counter-measured, observed reflections. The crystal contains discrete nitrogen bridged dimeric molecules possessing crystallographic \(\bar 1\) symmetry. Both NMR and mass spectral data indicate that this structure persists in solution and in the gas phase.