XPS investigations of ink‐jet printed paper

Different ink‐jet printed paper materials were investigated using X‐ray photoelectron spectroscopy (XPS) yielding the elemental composition of the near‐surface region of the papers. We found significant differences with respect to the detected elements and their atomic concentrations in the different inks studied here. Two different groups of inks could be identified by means of a lower ratio of the O and C atomic concentrations and lower concentrations in specific trace elements like Mg, Na and Si. High‐resolution spectra of C 1s and O 1s core levels allowed a detailed determination of the chemical state of the respective elements. On the basis of a detailed deconvolution of these XPS signals, significant differences between all the investigated ink‐jet printed papers were found, thereby allowing their discrimination. The applicability of the measurements and, more generally, the XPS technique for forensic investigations of paper are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Biochemisches Verhalten von Desoxyribonucleinsäure

Zusammenfassung Es wird eine durch DNS ausgel?ste biologische Wirkkette diskutiert. Durch DNS-Injektion lassen sich beim Warmblüter DNase-Aktivit?tserscheinungen hervorrufen. DNasen bewirken in niedrigen Konzentrationsbereichen 10⁻¹³-10⁻⁵ g/ml eine Steigerung der Zellzahl. In h?heren Konzentrationen wirken sie hemmend auf die Lebenst?tigkeit. Aufgrund dieser experimentellen Befunde ergibt sich ein selbstregelnder Mechanismus. Ausgeführt mit Mitteln der Deutschen Forschungsgemeinschaft.     

Hg2(OH)[BF4], the First Basic Mercurous Tetrafluoroborate

The first basic mercurous tetrafluoroborate, Hg₂(OH)[BF₄], was obtained through a synproportionation reaction of red mercuric oxide, HgO, and elemental mercury in a 35% solution of HBF₄ in water as colourless single crystals. The crystal structure (orthorhombic, Pbca, Z = 8, a = 985.0(1), b = 991.0(1), c = 1141.0(2) pm) contains [(HO)_1/2—Hg—Hg—(OH)_1/2]⁺ zig‐zag chains that are further connected via weak Hg—OH interchain interactions to layers between which the [BF₄]^— are located in an up and down fashion.     

GnRH binding RNA and DNA Spiegelmers: a novel approach toward GnRH antagonism

Mirror-image oligonucleotide ligands (Spiegelmers) that bind to the pharmacologically relevant target gonadotropin-releasing hormone I (GnRH) with high affinity and high specificity have been identified using the Spiegelmer technology. GnRH is a decapeptide that plays an important role in mammalian reproduction and sexual maturation and is associated with several benign and malignant diseases. First, aptamers that bind to D-GnRH with dissociation constants of 50-100 nM were isolated out of RNA and DNA libraries. The respective enantiomers of the DNA and RNA aptamers were synthesized, and their binding to L-GnRH was shown. These Spiegelmers bind to L-GnRH with similar affinity to that of the corresponding aptamers that bind to D-GnRH. We further demonstrated dose-dependent inhibition of GnRH-induced Ca(2+) release in Chinese hamster ovary cells that were stably transfected with the human GnRH receptor.     

Ab initio study of the binding of Trichostatin A (TSA) in the active site of histone deacetylase like protein (HDLP)

Histone deacetylase (HDAC) inhibitors have recently attracted considerable interest because of their therapeutic potential for the treatment of cell proliferative diseases. An X-ray structure of a very potent inhibitor, Trichostatin A (TSA), bound to HDLP (an HDAC analogue isolated from Aquifex aeolicus), is available. From this structure, an active site model (322 atoms), relevant for the binding of TSA and structural analogues, has been derived, and TSA has been minimized in this active site at HF 3-21G* level. The resulting conformation is in excellent accordance with the X-ray structure, and indicates a deprotonation of the hydroxamic acid in TSA by His 131. Also, a water molecule was minimized in the active site. In addition to a similar deprotonation, in accordance with a possible catalytic mechanism of HDAC as proposed by Finnin et al. (M. S. Finnin, J. R. Donigian, A. Cohen, V. M. Richon, R. A. Rifkind and P. A. Marks, Nature, 1999, 401, 188-193), a displacement of the resulting OH- ion in the active site was observed. Based on these results, the difference in energy of binding between TSA and water was calculated. The resulting value is realistic in respect to experimental binding affinities. Furthermore, the mechanism of action of the His 131-Asp 166 charge relay system was investigated. Although the Asp residue in this motif is known to substantially increase the basicity of the His residue, no proton transfer from His 131 to Asp 166 was observed on binding of TSA or water. However, in the empty protonated active site, this proton transfer does occur.     

Zur Kenntnis der Reaktionen von Carbonsäurechloriden in Lösungsmitteln mit Wolle

Zusammenfassung Wolle und-Keratose wurden mit Carbonsäure-chloriden in Dimethylsulfoxid mit Pyridinzusatz oder ohne Base bei 20–60 °C bis zu 4 Stunden umgesetzt. Die dabei eintretende Vernetzungsreaktion beruht auf der Bildung von Formaldehyd aus den Säurechloriden und Dimethylsulfoxid. Damit werden auch die Anafysendaten verständlich: geringe Gewichtsänderungen, Beteiligung des Lysins, keine Beteiligung der Carboxylgruppen, Verschwinden des Tyrosins erst nach saurer Totalhydrolyse. Läßt man Acylchloride in Dimethylformamid, Dimethylacetamid, Hexamethyl-phosphorsäuretriamid,-Butyrolacton und Methyl-pyrrolidon auf Wolle einwirken, so erfolgt N,O-Acylierung unter Gewichtszunahme.

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Summary Wool and -Keratose were reacted at 20–60° for 4 hours with acylchlorides in dimethylsulfoxide with addition of pyridine or without a base. The ensuing crosslinking reaction. was due to formation of formaldehyde by reaction of the acid chlorides with the solvent dimethylsulfoxide. This explains the analytical data found: small weight changes participation of lysine, no participation of the carboxylic groups, disappearance of tyrosine during the acid hydrolysis.If the acyl chlorides are reacted with wool in the solvents dimethylformamide, dimethylacetamide, hexamethyl-phosphortriamide,-butyrolacton and methyl-pyrrolidone, normal acylation and corresponding weight increases were found.

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Teil der DissertationH.-D. Scharf, RWTH Aachen, 1972; 21. Mitteilung über ,Reaktivität von Aminosäureseitenketten. 20. Mitteilung vgl.W. Wellner, D. Nissen und H. Zahn, Colloid u. Polymer Sci.255, 444 (1977).

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Jetzt Dynamit-Nobel AG., Troisdorf.

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Jetzt Wella AG, Darmstadt.

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Mit 4 Abbildungen und 8 Tabellen     

Highly conjugated p-quinonoid pi-extended tetrathiafulvalene derivatives: a class of highly distorted electron donors

A new class of pi-extended TTF-type electron donors (11 a-c) has been synthesized by Wittig-Horner olefination of bianthrone (9) with 1,3-dithiole phosphonate esters (10 a-c). In cyclic voltammetry experiments, donors 11 a-c reveal a single, electrochemically irreversible oxidation-yielding the corresponding dicationic products-at relatively low oxidation potentials (approximately 0.7-0.8 V). Theoretical calculations, performed at the DFT level (B3 P86/6-31 G*), predict a highly-folded C(2h) structure for 11 a. In the ground state, the molecule adopts a double saddle-like conformation to compensate the steric hindrance. The calculations suggest that the intramolecular charge transfer associated with the HOMO-->LUMO transition is responsible for an absorption band observed above 400 nm. While the radical cation 11 a*+ retains the folded C(2h) structure predicted for the neutral molecule as the most stable conformation, the dication 11 a(2+) has a fully aromatic D(2) structure, formed by an orthogonal 9,9'-bianthryl central unit to which two singly-charged dithiole rings are attached. The drastic conformational changes that compounds 11 undergo upon oxidation account for their electrochemical properties. By means of pulse radiolysis measurements, radical-induced one-electron oxidation of 11 a-c was shown to lead to the radical cation species (11 a-c*+), which were found to disproportionate with generation of the respective dication species (11 a-c(2+)) and the neutral molecules (11 a-c).