Single carbon nanotube optical spectroscopy.

This Minireview discusses novel insights into the electronic structure of carbon nanotubes obtained using single-molecule fluorescence spectroscopy. Fluorescence spectra from single nanotubes are well described by a single, Lorentzian lineshape. Nanotubes with identical structures fluoresce with different energies due to local electronic perturbations. Carbon nanotube fluorescence unexpectedly does not-show any intensity or spectral fluctuations at 300 K The lack of intensity blinking or bleaching demonstrates that carbon nanotubes have the potential to provide a stable, single-molecule infrared photon source, allowing for the exciting possibility of applications in quantum optics and biophotonics.     

Den Einfu? einiger Variabler auf die Intensit?t der R?ntgenfluorescenz-strahlung

Zusammenfassung 1-Naphthol kuppelt beim Erwärmen mit Kalium-p-nitrophenylantidiazotat in 2%iger Sodalösung zu einem Azofarbstoff, dessen Alkalisalz in Alkoholen mit blauer Farbe löslich ist. Diese Verbindung ist in Amylalkohol extrahierbar, worauf sich ein spezifischer Nachweis begründen läßt. Der Chemismus der Umsetzung wird diskutiert. Bei Ausführung als Tüpfelreaktion wird eine Erfassungsgrenze von 0,5g erhalten.     

Validation of quantitative polymerase chain reaction methodology for monitoring DNA as a surrogate marker for species material contamination in porcine heparin

Heparin is a widely used intravenous anticoagulant comprising of a very complex mixture of glycosaminoglycan chains, mainly derived from porcine intestinal mucosa. The species of origin and the absence of contaminants from other species are important determinants of the different physicochemical characteristics of heparin. They also determine the potential for introducing infectious and adventitious agents into heparin batches destined for medicinal use. We perform routine quantitative polymerase chain reaction (Q-PCR) release tests to confirm the quality of all crude heparin batches, including those used for the manufacture of enoxaparin sodium. Here we further demonstrate that the assessment of the DNA content in crude heparin is a good surrogate marker of contamination at the mucosa level. After spiking porcine mucosa with ovine mucosa and processing this material to form crude heparin, we were able to observe similar ratios of species-specific DNA in both the starting and end products. Experiments performed with 3,000 and 1,500 ppm contamination found these concentrations to be well above the detection limit for our assay of heparin batches. Additionally this Q-PCR method can be used to detect contamination in mucosa, thus providing a tool capable of monitoring for contaminants throughout the crude heparin manufacturing process. Q-PCR analysis of industrial crude heparin samples has confirmed over time the value of this method to assess the pure porcine origin of heparin.     

Multiresidue chromatographic method for the determination of macrolide residues in muscle by high-performance liquid chromatography with UV detection.

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of tilmicosin, tylosin, spiramycin, and its major metabolite neospiramycin was developed that is suitable for porcine, bovine, and poultry muscles. Macrolide residues were extracted from muscle with acetonitrile, fat was removed by liquid-liquid extraction with isooctane, and the extract was then cleaned on Bond Elut C18 cartridges. The HPLC separation was performed on an Inertsil ODS3 C18 column (150 x 4 mm) with 0.05% trifluoroacetic acid-acetonitrile in a gradient mode. Two different chromatographic gradients were used for tilmicosin-tylosin and spiramycin-neospiramycin, and the detection wavelengths were 287 and 232 nm, respectively. The method was validated from 1/2 the maximum residue limit (MRL) to 4 times the MRL with pork muscle samples. Mean recoveries were 60, 63.5, 51, and 42% for tilmicosin, tylosin, spiramycin, and neospiramycin, respectively. The detection limits are 15 micrograms/kg for tilmicosin and tylosin, 30 micrograms/kg for spiramycin, and 25 micrograms/kg for neospiramycin. Linearity, precision, and accuracy of the method were also tested.     

Studien über Eisen-Cyan-Komplexe mit organischen Verbindungen

Zusammenfassung Die Bildung des violetten Komplexes von Nitrosobenzol mit Natrium-pentacyanoamminferroat verläuft über eine Reduktion des Nitrosobenzol zu Phenylhydroxylamin und Einbau des letzteren in den Prussokomplex. Chinondioxim reagiert mit Prussosalzen als p-Nitrosophenylhydroxylamin unter Bildung eines blauen Komplexsalzes. Die Bildung von Chinondioxim aus Chinon und Hydroxylaminchlorhydrat und dessen Farbreaktion mit Natriumpentacyanoamminferroat wird als selektiver und empfindlicher Tüpfelnachweis auf p-Benzochinon verwendet.

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Summary The formation of the violet complex of nitrobenzene with sodium pentacyanoammineferroate occurs via a reduction of the nitrobenzene to phenylhydroxylamine and installation of the latter in the prusso complex. Quinone dioxime reacts with prusso salts asp-nitrosophenylhydroxylamine to yield a blue complex salt. The formation of quinone dioxime from quinone and hydroxylamine hydrochloride and its color reaction with sodium pentacyanoammineferroate is applied as a selective and sensitive spot test forp-benzoquinone.

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Résumé La formation du complexe violet entre le nitrosobenzène et le pentacyanoammine ferroate de sodium repose sur une réduction du nitrosobenzène en phénylhydroxylamine et sur la transformation de celle-ci en complexe prussique. La quinone-dioxime réagit avec les sels prussiques commep-nitrosophénylhydroxylamine avec formation d'un sel complexe bleu. La formation de la quinone-dioxime à partir de la quinone et du chlorhydrate d'hydroxylamine et sa réaction colorée avec le pentacyano-ammine ferroate de sodium sont utilisées comme recherche à la touche sélective et sensible de lap-benzoquinone.

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Herrn Prof. Dr. Ing.Fritz Feigl zum 70. Geburtstag gewidmet.     

Compact,low-cost Ti:Al2O3 laser for in vivo ultrahigh-resolution optical coherence tomography

A compact, low-cost, prismless Ti:Al2O3 laser with 176-nm bandwidth (FWHM) and 20-mW output power was developed. Ultrahigh-resolution ophthalmic optical coherence tomography (OCT) ex vivo imaging in an animal model with approximately 1.2-microm axial resolution and in vivo imaging in patients with macular pathologies with approximately 3-microm axial resolution were demonstrated. Owing to the pump laser, this light source significantly reduces the cost of broadband OCT systems. Furthermore, the source has great potential for clinical application of spectroscopic and ultrahigh-resolution OCT because of its small footprint (500 mm x 180 mm including the pump laser), user friendliness, stability, and reproducibility.