Fruchtsirupe, Marmeladen und Fruchtpr?parate

Ohne Zusammenfassung     

Untersuchung von Fetten

Ohne Zusammenfassung     

Connectivity and binding‐site recognition: Applications relevant to drug design

Here, we describe a family of methods based on residue–residue connectivity for characterizing binding sites and apply variants of the method to various types of protein–ligand complexes including proteases, allosteric‐binding sites, correctly and incorrectly docked poses, and inhibitors of protein–protein interactions. Residues within ligand‐binding sites have about 25% more contact neighbors than surface residues in general; high‐connectivity residues are found in contact with the ligand in 84% of all complexes studied. In addition, a k‐means algorithm was developed that may be useful for identifying potential binding sites with no obvious geometric or connectivity features. The analysis was primarily carried out on 61 protein–ligand structures from the MEROPS protease database, 250 protein–ligand structures from the PDBSelect (25%), and 30 protein–protein complexes. Analysis of four proteases with crystal structures for multiple bound ligands has shown that residues with high connectivity tend to have less variable side‐chain conformation. The relevance to drug design is discussed in terms of identifying allosteric‐binding sites, distinguishing between alternative docked poses and designing protein interface inhibitors. Taken together, this data indicate that residue–residue connectivity is highly relevant to medicinal chemistry. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010     

Detection and quantitation of ethylene oxide, 2-chloroethanol, and ethylene glycol with capillary gas chromatography

A procedure is described for detection and quantitation of ethylene oxide and two major reaction products. Detection of ethylene oxide residuals extracted from alcohol pads (cellulose) and plastic material is illustrated. Quantitation of the three compounds can be obtained with a single gas chromatographic (GC) analysis. A DB-Wax-30N, 0.25 mm i.d. column is used with 1:50 split injections with dimethylformamide as the solvent and 1:100 split injections with water as the solvent. A DB-Wax-30W, 0.32 mm i.d. column is used for on-column injections and 1:100 split water injections. Linearity of the three compounds is demonstrated.     

Investigation of radical intermediates in polymer sonochemistry

There is current interest in using high-intensity ultrasound to perform a range of chemical transformations, including polymerisation reactions. In this work, the technique of radical trapping, primarily using DPPH, has been used to measure radical production rates in a range of monomer and related systems when exposed to high intensity ultrasound. It has been shown that realistic rates of production can be obtained around room temperature equivalent to thermal decomposition rates > 100°C, making sonication a viable method for initiating polymerisation. Rates of initiation in a twophase organic in water system have also been measured. Some of the initiating species have been identified recording the ESR spectra of adducts with spin traps, although further analysis is needed before the complete range of radicals produced can be identified.     

Preparation and characterization of some structural variants of Cp*Ti(1,2-propandiolato) complexes

1,2-Propandiol reacts with Cp*Ti(CH₃)₃ by rapid liberation of methane to yield a dimetallic complex 6 of the net composition (Cp*Ti)₂(1,2-propandiolato)₃. The X-ray crystal structure analysis revealed an unsymmetrical bridging between the [Cp*Ti(1,2-propandiolato)] and [Cp*Ti(1,2-propandiolato)₂] subunits. Cp*TiCl₃ reacts with 1,2-propandiol in a 1:1 stoichiometry in the presence of excess pyridine by replacement of two chlorides by a 1,2-propandiolato ligand. The resulting product was isolated as a dimer 8 and characterized by X-ray diffraction. It exhibits a central Ti₂O₂ ring that was formed by bridging between the two [Cp*TiCl(1,2-propandiolato)] subunits using the oxygen atoms of the primary end of the ligand. From the reaction mixture a more complicated condensation product 9 was isolated in a small yield that contains two [Cp*TiCl(1,2-propandiolato)] units connected in a similar way by a Cp*-free [Ti(1,2-propandiolato)₂] moiety as revealed by its X-ray crystal structure analysis. Complex [Cp*TiCl(1,2-propandiolato)]₂ (8) gives an active catalyst for the syndiotactic polymerization of styrene upon treatment with excess methylalumoxane in toluene solution.     

Use of the Fourier transform infrared (FTIR) technique for determination of the composition of final phosphate coatings on grain-oriented electrical steel

Electrical steels are highly specialised, magnetically soft materials, used to form the cores that carry the magnetic flux in electrical machines such as motors, generators and transformers.