UV Raman spectroscopy--a technique for biological and mineralogical in situ planetary studies.

We report on the great advantages of using deep UV Raman system for in situ planetary applications. Among them are to be mentioned: (I) higher scattering efficiency compared to VIS-IR Raman excitation wavelengths, (II) electronic resonance effects which increase the intrinsically weak Raman signal thus improving the S/N ratio of the detected Raman signals and (III) spectral separation of Raman and fluorescence signals. All these advantages are making UV Raman a valuable technique for in situ planetary applications. Mineral as well as biological samples were analyzed using Raman deep UV excitation and the results are presented. For the mineral samples a comparison with excitation in the NIR-VIS spectral regions is made. The impact of fluorescence on Raman data acquisition at different laser excitation wavelengths is assessed. Making use of the resonance effects, spectra of microorganisms were recorded with a high S/N ratio, allowing afterwards a very precise identification and classification (to the strain level) of the measured samples.

UV Raman imaging--a promising tool for astrobiology: comparative Raman studies with different excitation wavelengths on SNC Martian meteorites.

The great capabilities of UV Raman imaging have been demonstrated on the three Martian meteorites: Sayh al Uhaymir, Dar al Gani, and Zagami. Raman spectra without disturbing fluorescence and with high signal-to-noise-ratios and full of spectral features were derived. This result is of utmost importance for the development of powerful instruments for space missions. By point scanning the surfaces of the meteorite samples, it was possible for the first time to construct UV-Raman images out of the array of Raman spectra. Deep-UV Raman images are to the best of our knowledge presented for the first time. The images were used for a discussion of the chemical-mineralogical composition and texture of the meteorite surfaces. Comparative Raman studies applying visible and NIR Raman excitation wavelengths demonstrate a much better performance for UV Raman excitation. This comparative study of different Raman excitation wavelengths at the same sample spots was done by constructing a versatile, robust sample holder with a fixed micro-raster. The overall advantages of UV resonance Raman spectroscopy in terms of sensitivity and selectivity are demonstrated and discussed. Finally the application of this new technique for a UV Raman instrument for envisaged astrobiological focused space missions is suggested.

On-line monitoring and identification of bioaerosols.

Fast analysis of bioaerosols in clean room environments is necessary in order to prevent contamination of pharmaceutical products, minimize machine downtimes, or both. The detection and identification of microbes will be carried out in several steps: After impaction of the aerosol on a surface, the particles are presorted with glancing light illumination and fluorescence imaging in order to distinguish between abiotic and biotic particles. Since only the biotic particles are of interest, the analysis time can be minimized due to reduction of the data set. The biotic particles are then analyzed further with Raman spectroscopy and identified with a support vector machine.

Chemotaxonomic identification of single bacteria by micro-Raman spectroscopy: application to clean-room-relevant biological contaminations.

Microorganisms, such as bacteria, which might be present as contamination inside an industrial food or pharmaceutical clean room process need to be identified on short time scales in order to minimize possible health hazards as well as production downtimes causing financial deficits. Here we describe the first results of single-particle micro-Raman measurements in combination with a classification method, the so-called support vector machine technique, allowing for a fast, reliable, and nondestructive online identification method for single bacteria.

Design and characterization of a tunable polarization-independent resonant grating filter.

We present the design, analysis and characterization of a polarization-independent tunable resonant grating filter. Polarization independence is achieved by setting the plane of incidence parallel to the grating grooves and optimizing the fill factor to obtain a strong reflection peak for all incident polarization states. Experimental measurements show that approximate angular insensitivity to the input polarization orientation concurrent with tunability over a wavelength range of roughly 1530 nm to 1560 nm is achieved. Modulation of the reflectivity peak shape with variations in the orientation of the incidence plane are observed, and found to be in qualitative agreement with theoretical predictions.

Tunable, oblique incidence resonant grating filter for telecommunications.

We have designed a tunable, oblique-incidence resonant grating filter that covers the C band as an add-drop device for incident TE-polarized light. We tune the filter by tilting a microelectromechanical systems platform onto which the filter is attached. The fabrication tolerances as well as the role of finite incident-beam size and limited device size were addressed. The maximum achievable efficiency of a finite-area device as well as a scaling law that relates the resonance peak width and the minimum device size is derived. In good agreement with simulations, measurements indicate a negligible change in shape of the resonance peak from 1526 nm at a 45 degrees angle of incidence to 1573 nm at a 53 degrees angle with a full width at half-maximum of 0.4 nm. In this range the shift of the peak wavelength is linear with respect to changes in the angle of incidence.

Interactions between photoperiodism and temperature with respect to the control of dormancy in the adult stage of Pterostichus oblongopunctatus F. (Col., Carabidae) : I. Experiments on gonad maturation under different climatic conditions in the laboratory.

Pterostichus oblongopunctatus belongs to the type of spring breeding carabids with adult hibernation. Ovarian maturation is under the control of photoperiod: the females need a change of day length to mature. The first step of egg maturation (previtellogenesis) is bound to short day, the second step (vitellogenesis) to long day.The short day effect is achieved almost only at temperatures of 10 to 15°C; it is completely suppressed by 20°.The males mature under very different photoperiods and temperatures, but long day diminishes the percentage of mature males slightly, as well as does the higher temperature of 20°C in short day as compared with 15°C.Simulation of climatic conditions as experienced by the beetles from autumn throughout winter until spring in the laboratory showed that a short span of favourable temperatures at short day as experienced in nature in autumn allows the females to accomplish the short day development. But this maturation effect is still more diminished the longer temperatures below 5°C act on the beetles. Following that, a second period of temperatures between 10-15°C must restore the short day maturation effect if full maturity shall be gained in the following long day.The beetles are able to store reserve materials under long day at 20°C. After such a period they are able to have a normal previtellogenesis in spite of a severe shortage of food during short day. These experiments indicate that the failure in short day development outside the temperature range of 10-15°C is not a matter of an especially well balanced over-all metabolism in this favourable temperature range. It seems rather that hormonal systems involved in the short day phase of oogenesis act only within this span of temperature.

Die jahreszeitliche Synchronisation der Gonadenreifung bei Agonum assimile Payk. (Coleopt. Carab.) durch Temperatur und Photoperiode.

The control of annual rhythmicity in Agonum assimile was investigated by dissections and by breeding experiments both with specimens captured in the field and these reared in the laboratory. A. assimile is a spring breeder with summer larvae. The beetles hatch from the pupa from July until September, hibernate and breed in the following spring from April until June. Only a part of the old generation dies during the winter. Beetles from the previous year form about half of the breeding population. Rearing to the adulthood under laboratory conditions is possible with a success of about 80-90%, depending on the quality of food. Maturation of the sexes in the laboratory is desynchronized when the beetles are kept at 20°C and under "long day" conditions; development of the males is delayed in this case. In both sexes maturation takes place potentially free of dormancy.Development of the female and male gonads is mainly under the control of photoperiod and retarded in different ways by decreasing day length (photoperiodic quiescence). Thereby a maturation of the females is hindered in the autumn, and slow, further development of the males during the winter is made possible. The termination of quiescence by the transition from the "short day" to "long day" in laboratory experiments, or by increasing day length in the spring, synchronizes complete development in both sexes. The females normally produce an offsping of 20-60 larvae. We succeeded in keeping laboratory bred specimens up to 3 years, over this span they could be brought to propagation several times.

The control of larval hibernation and of adult aestivation in the Carabid beetlesNebria brevicollis F. andPatrobus atrorufus stroem.

1. Nebria brevicollis andPatrobus atrorufus have hibernating larvae and adults that breed in autumn. The young adults hatch in spring and early summer and undergo an aestivation diapause before maturation and reproduction. 2. N. brevicollis hatches earlier and breeds later in the year thanP. atrorufus, so that it shows a summer diapause of about 3.5 months. The aestivation diapause ofP. atrorufus lasts only 1.5 months. 3. In the laboratory the larvae of both species need cold for their development. While cold (+2-4° C) is obligatory forN. brevicollis from the first instar onwards,P. atrorufus larvae tolerate higher temperatures (15° C) except for the third instar. Low temperatures seem to stimulate the development of this species, too, if applied from the first instar onwards. The duration of development ofN. brevicollis is about 1.5 months shorter than that ofP. atrorufus. Metamorphosis again demands higher temperatures at the end of the third instar in both species. 4. The aestivation diapause of the adults is dependent upon the photoperiod. Long-day prevents maturation of the ovaries in the females. Ovarian maturation needs about 1 month short-day inP. atrorufus and 2-3 months inN. brevicollis. In agreement with these resultsP. atrorufus breeds about 1 month andN. brevicollis 2.5 months after summer solstice. 5. Females ofP. atrorufus mature after short-day treatment at 20° C, while those ofN. brevicollis need a decline of temperature in addition. 6. A shift from 20 to 15° C in continuous long-day yields no mature females ofN. brevicollis after 2 months. A small number ofP. atrorufus females (19%) mature after 5 weeks under continuous long-day treatment at 15° C. 7. The males of both species ripen nearly independently of the applied photoperiod.

Zusammenhänge zwischen Tagesrhythmik, Jahresrhythmik und Habitatbindung bei Carabiden.

Carabid beetles of forest habitats are mostly hygrophilous and darkpreferring species. Nearly all of them are nocturnal, and the majority are autumn breeders. Most carabids from open field habitats are xerophilous, light-preferring and diurnal species, or they are indifferent to humidity and light and can be active by day and night. This group includes markedly more spring breeders than the forest species. The adaptative value of the observed correlations is discussed.

[Experiments on adult emergence rhythms in Carabid bettles]. / Versuche zur Schlüpfrhythmik bei Carabiden.

The emergence times of the following species of Carabid beetles were investigated in a long day of LD 18/6: Agonum assimile Payk., Pterostichus angustatus Dft., P. nigrita F., and P. oblongopunctatus F.The hatching of the beetles was examined by means of an automatically controlled photorecorder.In one series of experiments flash-light was used for taking photographs. In a second series photographs were taken only during the light phase by the light of a fluorescent tube of the same type as used for the illumination of the breeding chamber.Both series of experiments produced no evidence of the existence of a typical emergence rhythm in the four Carabid species. In each species the number of beetles hatched per hour is slightly greater during the phtophase than during the scotophase. This difference was statistically significant only for P. angustatus. From this it is concluded that some Carabid species have a latent capability for synchronization of emergence by a light dark change.The sexes of P. angustatus show no difference in the distribution of their emergence times.