New ultrarapid-scanning interferometer for FT-IR spectroscopy with microsecond time-resolution.

A novel Fourier-transform infrared (FT-IR) rapid-scan spectrometer has been developed (patent pending EP14194520.4) which yields 1000 times higher time resolution as compared to conventional rapid-scanning spectrometers. The central element to achieve faster scanning rates is based on a sonotrode whose front face represents the movable mirror of the interferometer. A prototype spectrometer with a time resolution of 13 µs was realized, capable of fully automated long-term measurements with a flow cell for liquid samples, here a photosynthetic membrane protein in solution. The performance of this novel spectrometer is demonstrated by recording the photoreaction of bacteriorhodopsin initiated by a short laser pulse that is synchronized to the data recording. The resulting data are critically compared to those obtained by step-scan spectroscopy and demonstrate the relevance of performing experiments on proteins in solution. The spectrometer allows for future investigations of fast, non-repetitive processes, whose investigation is challenging to step-scan FT-IR spectroscopy.

The use of chromogenic bacteria as coloured substitutes for pathogens: a simple strategy during design and development of a new method for sample pretreatment.

AIMS: In the present study, chromogenic (red) bacteria were used to simulate actual target bacteria during set-up and optimization of an isolation process of bacteria, designed for food samples. Isolation of bacteria from food in the context of molecular biological detection of food pathogens is a multistep process. Development of such a separation method requires continuous monitoring of the location of the presumable targets in the sample tubes. Therefore, red-coloured pigmented bacteria were used as substitutes for the actual target bacteria, during the establishment of a new sample preparation technique. METHODS AND RESULTS: The chromogenic bacteria Micrococcus roseus and Serratia marcescens were confirmed to withstand the physical (e.g. centrifugal forces) and chemical (e.g. lysis buffer composition) conditions required during establishment of the new technique. Furthermore, the suitability of these model bacteria to substitute for the actual target pathogens (Salmonella enterica subsp. enterica serovar Typhimurium and Listeria monocytogenes) was assured by testing the physical properties of the model bacteria with respect to the proposed separation methods. CONCLUSION: Visibility of the pigmented bacteria within the complex sample matrices served to allocate bacterial content during the various steps necessary for finalization of the method protocol. The presumptive bacterial targets can be allocated simply by visualization of their bright red colour silhouetted against the background sample matrix. SIGNIFICANCE AND IMPACT OF STUDY: The use of pigmented bacteria as substitutes for actual colourless target bacteria during design and development of a bacterial isolation method is a simple and inexpensive application. It saves a huge amount of time and resources, as the proof of principle of new methods is possible in rapid succession.

[Rotational angioplasty--recanalization of chronic arterial occlusion using a slowly rotating catheter. Clinical results with 100 patients]. / Rotationsangioplastik--Wiedereröffnung chronischer Arterienverschlüsse mit einem langsam rotierenden Katheter. Klinische Ergebnisse bei 100 Patienten.

Between December 1986 and January 1989, 100 patients with chronic occlusions of peripheral arteries were treated with the new technique of low speed rotational angioplasty. This uses a relatively thick, flexible and blunt catheter, which is driven by an electric motor (100 to 200 r.p.m.). The success rate in the superficial femoral and popliteal arteries of the initial intervention for occlusions less than 10 cm was 90%, for occlusions of less than 10 cm, it was 80%. Occlusions on which conventional techniques had failed were successfully recanalized in 65%. Recanalisation was also successful in seven out of 12 patients with occluded iliac arteries. There were no perforations or other serious complications. It is concluded that the new method is particularly effective and safe for recanalisation of chronic vascular occlusions and should also be considered for cases which previously could only be treated surgically.

Interference microscopic determination of the section thickness of different paraffin-embedded organ tissues.

With respect to the significance of the section thickness in quantitative-morphological studies the thickness of different paraffin-embedded tissue sections was determined by interference microscopy. Within the range of 3-5 microns the measurements revealed accordance of the measured section thickness with that adjusted on the sliding microtome. In the range surpassing 5 microns the section thickness obtained was in all cases lower than that adjusted on the microtome. The deviations were up to 40%.