Luminescence of ion-irradiated α-quartz

Optical functionality of materials used in devices is the basis of modern photonics. It depends on selected photoactive impurities or low-dimensional structures, which can be tailored by ion implantation. The present survey covers cathode-luminescence spectroscopy performed after Ge, Ba, Na, Rb and Cs ion implantation in α-quartz, in connection with dynamic, laser-induced and chemical epitaxy of the surface layers amorphized during the ion irradiation. The correlations, which emerged for various luminescence bands, ion species and thermal processing methods, allows one to classify the bands into ion-specific and intrinsic ones. The microstructural properties measured by ion beam analysis and transmission electron microscopy will be combined with the luminescence data, and the role of photoactive defects in quartz and nanoparticles of the implants will be discussed. The technologically most attractive case of double Rb/Ge implantation will be highlighted, which combines the achievement of full chemical epitaxy (due to the alkali ions) and a high light output (due to Ge atoms). Finally, some investigations suggested to better understand the interplay between nanostructure and light emission in ion-doped quartz and the enormous potential for photonic application will be outlined.     

Effects of N-application on utilization of 15N and 13C and quality in two wheat cultivars

We studied N uptake and distribution in wheat, and the incorporation of nitrogen and carbon into gluten and non-gluten proteins using a double-labelling approach with ¹⁵N and ¹³C. Doses of N-fertilizer were split and applied at emergence, onset of stem elongation, and heading at rates of 280/140/140 mg N pot^?1, respectively simulating 90/45/45 kg N ha^?1. Five different combinations of N-fertilizations containing no or 10 % ¹⁵N were performed. The recovery of ¹⁵N added at the stages emergence, stem elongation or heading were 42, 60, and 64 %. Application of ¹⁵N at all three stages yielded in 51 % recovery. Remobilisation of straw N was greater for Golia. The ¹⁵N concentration in gluten proteins of Golia show higher values than Gönen. The ratio of ¹⁵N gluten/¹⁵N non-gluten proteins of Golia were higher, which implies a lower non-gluten protein activity during grain filling. The ¹³C concentration in gluten and non-gluten proteins did not differ between both cultivars.     

A Convenient Preparation of Dimethyl and Diethyl Oxaloacetate

The title compounds have usually been prepared as their sodium salts by Claisen condensations with acetic and oxalic acid esters and strong bases such as sodium alkoxides as catalysts.^1,2 In this communication we want to present a very mild and convenient route to both title compounds starting from the corresponding methyl or ethyl acetylenedicarboxylates.     

Assembling proteomics data as a prerequisite for the analysis of large scale experiments

Background  

Despite the complete determination of the genome sequence of a huge number of bacteria, their proteomes remain relatively poorly defined. Beside new methods to increase the number of identified proteins new database applications are necessary to store and present results of large- scale proteomics experiments.     

“Umgepolte” 1.3-diaza-fulvene

6-Substituted 2.4-diamino-1.3-diazafulvenes with inverse fulvene polarity are readily available from 2.4.5-tris-(diethylamino)-4-ethoxy-4H-imidazole and active methylene compounds.