Near infrared spectroscopy to study the brain: an overview

This paper gives an overview of principles, technologies, and applications using near infrared spectrometry and imaging (NIRS and NIRI) to study brain function. The physical background is reviewed and technologies and their properties are discussed. Advantages and limitations of NIRI are described. The basic functional signals obtained by NIRI, the neuronal and the hemodynamic signal are described and in particular publications about the former are reviewed. Applications in adults and neonates are reviewed, too.     

Optisch aktive 3-Amino-2H-azirine als Bausteine für enantiomerenreine α,α-disubstituierte α-Aminosäuren: Synthese des α-Methylphenylalanin-Synthons and Einbau in Modell-Peptide

Optically Active 3-Amino-2H-azirines as Synthons for Enantiomerically Pure αα-Disubstituted α-Amino Acids: Synthesis of the α-Methylphenylalanine Synthons and Some Model Peptides The synthesis of a novel 2-benzyl-2-methyl-3-amino-2H-azirine derivative with a chiral amino group is described. Chromatographic separation of the diastereoisomer mixture yielded the pure diastereoisomers 9a and 9b (Scheme 4) which are the D - and L -2-methylphenylalanine ((α-Me)Phe) synthons, respectively. The reaction of 9a and 9b with thiobenzoic acid and with Z-leucine yielded the monothiodiamides 10a and 10b (Scheme 5) and the dipeptide derivatives 11a and 11b (Scheme 6), respectively. Methanolysis of 11b yielded 12b . The absolute configuration of 10a was established by X-ray crystallography. The absolute configuration of (α-Me)Phe in 12b has been deduced from the known configuration of L -leucine.     

Ein neues 3-Amino-2H-azirin als Aib-Pro-Baustein: Synthese des C-terminalen Nonapeptids von Trichovirin I 1B

A New 3-Amino-2H-azirine as an Aib-Pro Synthon: Synthesis of the C-Terminal Nonapeptide of Trichovirin I 1B The synthesis of methyl N-(2,2-dimethyl-2H-azirin-3-yl)-L -prolinate ( 3 ), a novel 3-amino-2H-azirine, is described (Scheme 2). It is shown that the reaction of COCl₂ with thioamide 5 is remarkably faster than with the corresponding amide 4 , and the yield of 3 is much better in the synthesis starting with 5 . The 3-amino-2H-azirine 3 has been used as a building block of the dipeptide moieties Aib-Pro in the synthesis of nonapeptide 17 (Schemes 4 and 5), the C-terminal 6–14 segment of the peptaibole trichovirin I 1B. The structure of 17 was established by single-crystal X-ray crystallography (Figs.1 and 2).     

Influence of growth conditions on the structural,optical, and electrical properties of ZnSe films

ZnSe films were grown by chemical vapour deposition on GaAs substrates. The influence of the source temperature (between 820 and 900° C) and the substrate temperature (between 620 and 790° C) on the film properties were investigated by Hall measurements, X-ray diffraction, and photoluminescence. With respect to blue luminescent devices the ratio of excitonic to deep level transitions was found to be optimum at low growth rates when the source temperatures were kept below 840° C. P-type conduction up to a net carrier concentration of 8×10¹⁸ cm^–3 could be obtained by substrate temperatures above 700° C. Lattice contraction versus substrate temperature pointed to a reduced incorporation of donors at higher growth temperatures.     

Microbiological assay of avoparcin in animal feeds and pre-mixes--co-operative study.

A microbiological method for the determination of the antibiotic growth promoter avoparcin in animal feeds and pre-mixes was first published in 1979. The existing method has been applied to new matrices as commercial use of avoparcin has spread. Problems with the existing analytical procedure have been reported, particularly in Germany. This paper identifies the causes of the problems and includes revisions to the existing analytical procedure. The testing of these revisions in co-operative studies with up to five German official laboratories is also reported.