Donor-acceptor nanoensembles of soluble carbon nanotubes

Donor-acceptor nanoensembles, prepared via electrostatic interactions of single wall carbon nanotubes and porphyrin salts, give rise to photoinduced intra-complex charge separation that lasts tens of microseconds.Peer reviewedChemistr

Synthesis and Aggregation Properties of Highly Charged, Water Soluble Porphyrins

Schwerpunkt dieser Arbeit war die Synthese und Charakterisierung von hochgeladenen, wasserlöslichen anionischen und kationischen Metalloporphyrinderivaten. Anschließend wurden die Agregationseigenschaften mit hochgeladenen Polyelektrolytsystemen wie funktionalisierten SWCNTs und Dendrofullerensystemen untersucht. in weiterführenden Experimenten wurde aus meheren Schichten dieser Polyelektrolyte eine photoaktiven Redoxelektrode aufgebaut. Des Weiteren wurden die Aggregationseigenschaften untereinander und mit anderen Polyelektrolytsystemen mittels Gelelektrophorese untersucht und so dei Gelelektrophorese in der organischen Chemie etabliert. Des weiteren wurde der Wasser- und NO-Austausch am oktakationischen Eisenporphyrin untersucht sowie der Einsatz dieser sehr gut wasserlöslichen Porphyrine in der Medizin als Tracersubstanzen untersucht.In the course of this work different highly charged water-soluble cationic and anionic metalloporphyrin derivatives have been prepared and characterized. Their aggregation properties with other polyelectrolytes such as functionalised SWCNTs and Dendrofullerenes has been studied. In further experiments monomolecular layers of different charged polyelectrolytes were deposited on a transparent ITO-electrode and after light excitation a photocurrent was measured. The aggregational behaviour has also benn studied via gel-electrophoresis. The role of ionic charges on the reactivity of the iron-center iron-porphyrins towards water and NO exchange was investigated

A comparative mechanistic study of the reversible binding of NO to a water-soluble octa-cationic Fe(III) porphyrin complex

The water-soluble, non-mu-oxo dimer-forming porphyrin, [5,10,15,20-tetrakis-4'-t-butylphenyl-2',6'-bis-(N-methylene-(4''-t-butylpyridinium))porphyrinato]iron(III) octabromide, (P(8+))Fe(III), with eight positively charged substituents in the ortho positions of the phenyl rings, was characterized by UV-vis and 1H NMR spectroscopy and 17O NMR water-exchange studies in aqueous solution. Spectrophotometric titrations of (P(8+))Fe(III) indicated a pKa1 value of 5.0 for coordinated water in (P(8+))Fe(III)(H2O)2. The monohydroxo-ligated (P(8+))Fe(III)(OH)(H2O) formed at 5 < pH < 12 has a weakly bound water molecule that undergoes an exchange reaction, k(ex) = 2.4 x 10(6) s(-1), significantly faster than water exchange on (P(8+))Fe(III)(H2O)2, viz. k(ex) = 5.5 x 10(4) s(-1) at 25 degrees C. The porphyrin complex reacts with nitric oxide to yield the nitrosyl adduct, (P(8+))Fe(II)(NO+)(L) (L = H2O or OH-). The diaqua-ligated (P(8+))Fe(III)(H2O)2 binds and releases NO according to a dissociatively activated mechanism, analogous to that reported earlier for other (P)Fe(III)(H2O)2 complexes. Coordination of NO to (P(8+))Fe(III)(OH)(H2O) at high pH follows an associative mode, as evidenced by negative deltaS(double dagger)(on) and deltaV(double dagger)(on) values measured for this reaction. The observed ca. 10-fold decrease in the NO binding rate on going from six-coordinate (P(8+))Fe(III)(H2O)2 (k(on) = 15.1 x 10(3) M(-1) s(-1)) to (P(8+))Fe(III)(OH)(H2O) (k(on) = 1.56 x 10(3) M(-1) s(-1) at 25 degrees C) is ascribed to the different nature of the rate-limiting step for NO binding at low and high pH, respectively. The results are compared with data reported for other water-soluble iron(III) porphyrins with positively and negatively charged meso substituents. Influence of the porphyrin periphery on the dynamics of reversible NO binding to these (P)Fe(III) complexes as a function of pH is discussed on the basis of available experimental data

Streptococcus dysgalactiae subsp. equisimilis: two cases of tonsillitis

We described two case reports of S. dysgalactiae subsp. equisimilis tonsillitis occurred from January 2005 to January 2007, among patients who come to our observation during these two years. These patients are paradigmatic of some conditions: adult age, absence of underlying diseases, outbreak of similar pharyngo-tonsillar sympyomatology, unsuccessful oral penicillin therapy, isolation of S. dysgalactiae subsp. equisimilis from throat swab, complete recovery after oral beta-lattamic antibiotic therapy, but total clearance of the microorganism only after oral macrolides administrations. Thus, the intracellular localization of S. dysgalactiae subsp. equismilis, could be in charge of the failure of beta-lattamic antibiotics therapy

Isolation of multidrug-resistant Enterobacter cloacae and comparison among clavulanate-tazobactam and sulbactam-synergy by using a double-disk synergy test

False negative results of double-disk synergy test with Enterobacter cloacae are common, as AmpC-enzymes may mask ESBLs elaboration. We increased the sensitivity of the method by using both clavulanate- and tazobactam/sulbactam; hence, we suggest to use all the three inhibitors to screen ESBLs in AmpC ß-lactamases producing organisms

Femoral Prosthesis Infection by Rhodotorula mucilaginosa▿

This case report is a case history of a femoral prosthesis infection caused by Rhodotorula mucilaginosa in a human immunodeficiency virus patient. Though the pathogenicity of this organism for bone tissue has been previously reported, this is the first reported case of an orthopedic prosthesis infection by this species of the genus Rhodotorula