Salting-out surfactant extraction of porphyrins and metalloporphyrin from aqueous non-ionic surfactant solutions

A number of cloud point temperature-depressing electrolytes have been investigated for the separation of a non-ionic surfactant (Triton X-100) from aqueous solutions and the corresponding extraction of the organic solutes into the smaller volume surfactant-rich phase using the salting-out method. High extraction efficiencies and preconcentration factors were obtained at room temperature for the extraction of several hydrophilic and hydrophobic metal-free porphyrins (uroporphyrin, coproporphyrin, protoporphyrin and hematoporphyrin) and one metalloporphyrin (iron-protoporphyrin) that were dissolved in the aqueous non-ionic surfactant solutions. Possible mechanisms responsible for the efficient extraction of these important biological molecules into the surfactant-rich layer are discussed.     

Neighborhood behavior of in silico structural spaces with respect to in vitro activity spaces-a novel understanding of the molecular similarity principle in the context of multiple receptor binding profiles

As a consequence of recent advances in the field of High Throughput Screening, the systematic testing ("in vitro profiling") of compounds against a panel of targets covering different therapeutic areas is nowadays used to generate relevant information with respect to the in vivo behavior of drug candidates. However, the development of chemoinformatics tools required for the exploitation of such data is yet in an incipient phase. In this paper, a formalism for the analysis of activity profile vectors (describing the experimental responses of compounds in each of the considered activity tests) is introduced and applied at the study of Neighborhood Behavior (NB; the hypothesis that structurally similar compounds display similar biological properties) of molecular similarity metrics. The experimental activity profiles define an Activity Space in which more than 500 drugs and reference compounds are positioned, their coordinates being inhibitory propensities in the included tests and unambiguously characterizing a molecule in terms of its receptor binding properties. While previous studies of Neighborhood Behavior had to rely on a loose classification of compounds in terms of the therapeutic areas they were designed for, here the NB of a calculated "in silico" similarity metric has been redefined as a relationships between intermolecular dissimilarity scores in the "structural" and "activity" spaces, respectively, and expressed in terms of two quantitative criteria: "consistency" (the propensity of the metric to selectively rank activity-related compound pairs among the structurally most similar pairs) and "completeness" (monitoring the retrieval rate of activity-related compound pairs among the best ranked pairs of structural neighbors). These criteria were used to calibrate and validate a similarity metric based on Fuzzy Bipolar Pharmacophore Fingerprints.     

Beitrag zur Kenntnis des Systems Chrom-Mangan-Stickstoff

The system Cr–Mn–N has been investigated by X-ray technique in three isothermal sections at 800, 1,000 and 1,200°C and at nitrogen pressures ranging from 1 to 800 atm. The binary compounds Cr₂N and Mn₂N form a complete series of solid solutions. The mononitride phase field extends from CrN to (Cr_0.21Mn_0.79)N_0.80 at 1,000°C and 800 atm N₂, whereas at normal pressure only a small portion of chromium atoms in CrN can be substituted by manganese atoms.

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Auszug aus der DiplomarbeitE. Horvath, Technische Universität Wien, 1968.     

Preparation,Properties, and ESCA Characterization of Vanadium Surface Compounds on Silicagel. II

Binding energy (BE) behavior and signal intensity as function of V conc. and ligands L were critically examined in Vⁿ/SiO₂ species (where n = +5, +4, and +3) and securing of optimized products and ESCA samples is described. The results moreover demonstrate conditions and approaches whereby ESCA can provide reliable information on highly diluted surface compound systems. From aquous media 1.0–1.2 wt. % V^V and 0.4–1.2 wt. % V^III proved to be preferred ranges whereas in non aqueous (metalorganic) preparates the surprisingly low concentration of 0.4–0.15 wt. % V^III gave usable spectra and even 0.4 wt. % V^V could be measured. ESCA data with the peroxo complex (?Si? O)₃V? (O₂) (I) confirmed these trends. Superiorly subdivided surface compounds (reflected in the quality of spectra) are obtainable from V[N(SiMe₃)₂]₃ impregnations where 0.4–0.5 wt. % V^III (or V^V) are maximum/optimum conc. limits. Evidence for formulating Vⁿ/SiO₂ as three legged surface compounds is summarized and diagnostic/predictive uses of the additivity principle for surface electron states illustrated. In the (?Si? O)₃V? L series, where L = none, ?O, and ? (O₂) positive ΔBE shifts for ?Si? O? V (0.7 eV); V?O (0.6 eV); and V? (O₂) (0.4 eV) were estimated. Tentative BE contributions of some donor ligands (and ? Cl) are also suggested. In (I) ESCA indicated a formal oxidation state of approx. +4. Certain limits (precautions) with ESCA are noted and extensions of the additivity relationship discussed.     

Manganese(II) Silylamides

Mn[N(SiMe₃)₂]₂(THF) ( I ) (Me = methyl, THF = tetrahydrofuran) was obtained on large scale from “active” MnCl₂ and LiN(SiMe₃)₂ in THE in 85–93% yield. The novel, theoretically interesting tetra-coordinated Mn[N(SiMe₃)₂]₂L₂ series was derived from I , where L = THF, pyridine and t-butyleyanide. All these species are quite stable thermally and exhibit exteme oxygen sensitivity. Preparation, properties, and reactions of unsymmetrically substituted (“hemi”) X? Mn? Y type compounds are presented also, where X = ? Cl, ? NO₃ and n = butyl, and Y = ? N(SiMe₃)₂ and ? OR. From Cl? Mn? N(SiMe₃)₂, with or without coordinated THF being present, the unusual (Mn{SiMe₃)₂, was isolated as yellow crystals. The “hemi” Mn(II)-system exhibits only moderate thermal stability and tends to disproportionate. Many derivatives are photosensitive, especially with UV light.     

Screening of urinary coproporphyrin using cloud point extraction and chemiluminescence detection

A simple screening test was developed for the sensitive and selective measurement of urinary coproporphyrin. In this screening test, efficient and selective extraction/pre-concentration of coproporphyrin from the aqueous medium(urine) into a much smaller volume phase containing a common non-ionic surfactant (Triton X-100) and ethyl acetate was accomplished by the addition of a relatively large amount of a cloud point depressing electrolyte (K(3)PO(4)) into the sample solution to effect cloud point separation. Sensitive and selective detection of coproporphyrin in the mixed Triton X-100 and ethyl acetate phase was performed via chemical excitation using the peroxyoxalate chemiluminescence reaction. The effects of surfactant and cations (from the cloud point depressing electrolyte) on the chemiluminescence intensity of coproporphyrin were briefly investigated. Furthermore, the spectrum of urinary coproporphyrin obtained using the present chemiluminescence method was briefly compared with that obtained from fluorescence method.     

Analysis of lignin precipitates on ozone treated kraft pulp by FTIR and AFM

The process of ozone treatment of high kappa kraft pulp is studied using polarization modulated Fourier transform infrared spectroscopy and atomic force microscopy. The complementary information from the two methods enables a detailed analysis of reaction sites on the fibers, and gives a detailed view of the reaction mechanisms of delignification by ozone treatment. Furthermore we describe a simple method to measure the kappa number of paper sheets that can be used on-line.