Analysis of propionate-degrading consortia from agricultural biogas plants.

In order to investigate the propionate-degrading community of agricultural biogas plants, four propionate-degrading consortia (Ap1a, N12, G12, and Wp2a) were established from different biogas plants which were fed with renewable resources. The consortia were cultivated in a batch for a period of 2-4 years and then analyzed in an 8-week batch experiment for microbial succession during propionate degradation. Community shifts showed considerable propagation of Syntrophobacter sulfatireducens, Cryptanaerobacter sp.

Design and application of a synthetic DNA standard for real-time PCR analysis of microbial communities in a biogas digester.

A synthetic DNA fragment containing primer binding sites for the quantification of ten different microbial groups was constructed and evaluated as a reliable enumeration standard for quantitative real-time PCR (qPCR) analyses. This approach has been exemplary verified for the quantification of several methanogenic orders and families in a series of samples drawn from a mesophilic biogas plant. Furthermore, the total amounts of bacteria as well as the number of sulfate-reducing and propionic acid bacteria as potential methanogenic interaction partners were successfully determined.

Clifford Fourier transform on vector fields.

Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields.

Superelastic nickel titanium alloy retraction springs--an experimental investigation of force systems.

The purpose of the present investigation was to study the mechanical characteristics of canine retraction springs made of superelastic nickel titanium (NiTi) alloys. A modified Burstone T-loop was used to construct an experimental canine retraction spring 10 mm in height and 10 mm in length. Twenty-five NiTi T-segments were hand made from the superelastic orthodontic alloys Ormco NiTi and Soar Sentalloy (dimensions 0.