Strukturaufklärung von ausgewählten nitro- und sulfonsäuresubstituierten 1,2-Naphthochinon-2-diaziden

Structure Determination of Selected Nitro and Sulfonic Acid Substituted 1,2-Naphthoquinone-2-diazides Selected nitro derivatives of 1,2-naphtoquinone-2-diazide 2 and 5 have been synthesized, the position of the NO₂-group has been unambigously determined by means of ¹H and ¹³C n.m.r. spectroscopy, and the structure of these compounds has been comprehensively determined in relation to unsubstituted 1 and sulfonic acid substituted derivatives 3 , 3a , 4 and 4a . Furthermore, the spectroscopical behaviour, especially in the uv/vis region, was examined in correlation to quantum chemical calculations.     

Specific analysis of EBSD data to study the texture inheritance due to the β → α phase transformation

A specific processing of EBSD data is proposed to study the texture inheritance of titanium or zirconium alloys. A non standard misorientation map is calculated to localise the colonies inherited from the same parent grain. The calculation of the parent orientation from its inherited variants detailed in previous works has been adapted to the data obtained from an automated EBSD analysis. Finally, a method to derive the orientation map of the parent phase from that of the inherited phase is proposed. The resulting and COMs are used to study some aspects of the variant selection occurring in the transformation of a T40 sample.     

The nature of the photochromism arising in the nanosized MoO3 films

We carried out the experiments which show unambiguously that not one, as it was commonly accepted, but three optical absorption bands corresponding to different color centers arise in the nanosized MoO₃ films due to hydrogen atoms. Varying the conditions for the photoinjection of hydrogen into the MoO₃ films, it is possible to change drastically the correlation between the concentrations of different arising centers, which in turn yields the great difference in the optical absorption spectra. Our findings are crucial for understanding of the nature of electrochromism and photochromism not only in MoO₃ films but also in the series of the transition metal oxide films.     

An enzymatic method for preparation of homopolymannuronate blocks and strictly alternating sequences of mannuronic and guluronic units

Two Pseudomonas aeruginosa alginates were lysed by an overexpressed polymannuronate lyase AlxMB (only acting on two or more consecutive, nonacetylated mannuronate units) to prepare either mannuronate blocks (poly-M blocks) with dp approximately 30, or strictly alternating sequences of mannuronic and guluronic acid (poly-MG blocks) with dp > 20. The poly-M blocks were obtained by lysis of a P. aeruginosa polymannuronate that has 50% O-acetylation at C-2 and C-3. The poly-MG blocks were obtained from a P. aeruginosa alginate that contained both mannuronate and guluronate residues. The polysaccharide was first deacetylated and then treated with the lyase to excise the mannuronate units from the alternating-MG blocks. Both types of blocks should have potent biological effects and should provide useful specific substrates for characterisation of other alginate lyases.     

Efficacy of six anthelmintics against luminal stages of Baylisascaris procyonis in naturally infected raccoons (Procyon lotor)

The efficacy of six anthelmintics against natural infections of Baylisascaris procyonis in raccoons (n = 7 per drug) was determined in a series of critical tests. The drugs were given via moist cat food as a single dose or once daily for three consecutive days. Raccoons treated with pyrantel embonate (1 x 20 mg base kg-1 bodyweight (bwt.)), ivermectin (1 x 1 mg kg-1 bwt.), moxidectin (1 x 1 mg kg-1 bwt.), albendazole (3 x 50 mg kg-1 bwt.), fenbendazole (3 x 50 mg kg-1 bwt.) or flubendazole (3 x 22 mg kg-1 bwt.) expelled 1-198, 2-24, 2-14, 3-80, 2-70, or 2-35 B. procyonis stages, respectively, within the faeces. No roundworm was detected in any raccoon at post mortem examinations 7 days after the end of treatment. These results suggest that any of the six anthelmintics can be used at the dose rates tested in a deworming programme for captive raccoons.     

Spanen metallischer Konstruktionswerkstoffe geringer Dichte

Machining of light metals Magnesium, aluminium and titanium are the only light metals that are also used in construction. They offer a significant prerequisite for weight reduction of workpieces. Especially the automotive and the aerospace industry have an increasing interest in using these lightweight materials as well as their alloys. The machining of light metals however is accompanied with several problems. With increasing the cutting speed high adhesive and abrasive effects between the cutting tool material and the workpiece material can occur. These effects lead to unsteady processes and also have a negative influence on the quality of functional surfaces as well as their subsurface properties. The influence of cutting tool materials, tool coatings and cutting conditions affecting the process when cutting magnesium, aluminium and titanium alloys is described. Adhesion can be reduced when machining magnesium and aluminium alloys in particular by the application of diamond-coated tools and by PCD-inserts. Diamond tools, due to their low coefficient of friction and the high thermal conductivity, furthermore contribute to the decrease of the thermal load within the contact zone between workpiece and cutting tool. Subsequently the danger of magnesium chip ignition can be minimized. For the machining of titanium alloys modern coatings based on (Ti,Al)N and TiCTiN are applied to reduce the adhesive and abrasive wear.     

Chromatographic separation of mono- and oligomeric carbohydrates from biological materials with the use of HPLC glass columns

By means of HPLC mono- and oligomeric carbohydrates are separated on silica, modified chemically with aminopropyl groups or impregnated in situ with an amine modifier (piperazine). Fundamentals of this sugar analysis are self-packed glass columns. The advantages of these columns are high efficiencies and handy column plugs. They are chemically inert and can be packed in different length with different HPLC packings. Applications of HPLC technique using glass columns are demonstrated by way of qualitative and quantitative determinations of carbohydrates in different food-stuffs and in polysaccharides (e.g. starch, regenerated fibre), hydrolyzed under acid and enzymatic conditions.