Karol Hensel

Past and current status of sturgeons in the upper and middle Danube River

Of the six species of sturgeons native to the Danube basin, five occurred in the upper and middle Danube. Among anadromous sturgeons were the large winter races of beluga, Huso huso, Russian sturgeon, Acipenser gueldenstaedtii, and stellate sturgeon, A. stellatus, which ascended the middle, and sometimes also the upper Danube, to spawn. Due to overfishing, followed by severe habitat alteration including damming and pollution, these anadromous sturgeons are critically endangered or extirpated from the upper and middle Danube. Acipenser gueldenstaedtii and A. nudiventris are represented only as resident non-migratory races with very small populations. The most abundant and widely distributed species is the sterlet, A. ruthenus, although it is presently limited to the middle Danube. Its population increased in some sections of the middle Danube during the past 15 years, presumably because of improving water quality, but this species remains at risk because of continuing habitat degradation.

DC microdischarges inside porous ceramics

The hybrid plasma-catalyst system represents an effective method for the pollutant abatement from car exhaust. A problem, however, is a limited volume of the generated plasma, and a pressure drop across the catalyst layer. A new approach on the generation of microdischarges inside porous ceramic materials is reported. The results show that the stable generation of microdischarges can be observed only in ceramics with specific pore size.

Effects of air transient spark discharge and helium plasma jet on water, bacteria, cells, and biomolecules

Atmospheric pressure DC-driven self-pulsing transient spark (TS) discharge operated in air and pulse-driven dielectric barrier discharge plasma jet (PJ) operated in helium in contact with water solutions were used for inducing chemical effects in water solutions, and the treatment of bacteria (Escherichia coli), mammalian cells (Vero line normal cells, HeLa line cancerous cells), deoxyribonucleic acid (dsDNA), and protein (bovine serum albumin). Two different methods of water solution supply were used in the TS: water electrode system and water spray system. The effects of both TS systems and the PJ were compared, as well as a direct exposure of the solution to the discharge with an indirect exposure to the discharge activated gas flow. The chemical analysis of water solutions was performed by using colorimetric methods of UV-VIS absorption spectrophotometry. The bactericidal effects of the discharges on bacteria were evaluated by standard microbiological plate count method. Viability, apoptosis and cell cycle were assessed in normal and cancerous cells. Viability of cells was evaluated by trypan blue exclusion test, apoptosis by Annexin V-FITC/propidium iodide assay, and cell cycle progression by propidium iodide/RNase test. The effect of the discharges on deoxyribonucleic acid and protein were evaluated by fluorescence and UV absorption spectroscopy. The results of bacterial and mammalian cell viability, apoptosis, and cell cycle clearly show that cold plasma can inactivate bacteria and selectively target cancerous cells, which is very important for possible future development of new plasma therapeutic strategies in biomedicine. The authors found that all investigated bio-effects were stronger with the air TS discharge than with the He PJ, even in indirect exposure.

Prelude: Looking at Early Development in Fishes

The seed that gave fruit to the workshop from which this volume was derived’ was planted sometime in July 1992 during Vlado’s first exchange visit to Gordon’s laboratory in England. The laboratory was not big, it was not particularly tidy and it was rather modest with respect to equipment. It was there that the first measurements of some small specimens of roach were taken, ignoring the question whether they were larvae or juveniles. A couple of weeks later, we started to discuss the possible correlations between changes in mensural characters and habitat u, e that fish undergo during their early ontogeny and the possible influence of human activities (fragmentation of river systems) on the phenotype. We found some answers (e.g. Kovac & Copp 1996), however, as usual, each answer triggered a proliferation of new questions, some of which were later not expressed exactly in the way we intended (Copp & Kovac 1996).

A New Species of Gymnocephalus (Pisces: Percidae) from the Danube, with Remarks on the Genus

metrurus oreni. Sea Fish. Res. Sta., Haifa 60:1-12. FOURMANOIR, P. 1965. Liste complementaire des poissons marins de Nha-Trang. Cahiers ORSTOM, Oc6anographie, no. spec.:1-114. . 1969.

Sliding Discharge Inside Glass Capillaries

The generation of stable and homogenous plasma inside an automobile honeycomb catalyst is very difficult. This paper presents a technique to create plasma inside the thin channels of the honeycomb monolith by using a sliding discharge. The electrical and optical properties of the discharge are described.

To be a juvenile and not to be a larva : an attempt to synthesize

The question — when does a fish becomes a juvenile — might seem strange to some, and even totally worthless, mainly to those fish and fishery biologists who designate all the small ontogenetic stages of fishes by the banal term ‘fry’ (for a commentary on this unfortunate term, see Balon 1990). Despite this, a group of predominantly younger scientists met at a workshop in Bratislava to exchange views on this topic. Ontogeny is a process during which one event is related to another and everything is related to everything else. Therefore, besides the title subject, the participants of the workshop discussed also such topics as fish metamorphosis, whether the larva period begins with hatching or with the onset of exogenous feeding, and eventually, whether fish ontogeny is saltatory or otherwise.

Measurement of the electron density in Transient Spark discharge

This paper presents our measurements of the electron density in a streamer-to-spark transition discharge, which is named transient spark (TS), in atmospheric pressure air. Despite the dc applied voltage, TS has a pulsed character with short (~10–100 ns) high current (>1 A) pulses, with a repetition frequency on the order of kHz. The electron density ne ~ 1017 cm−3 at maximum is reached in TS with repetition frequencies below ~3 kHz, using relatively low power delivered to the plasma (0.2–3 W).The temporal evolution of ne was estimated from the resistance of the plasma discharge, which was obtained by a detailed analysis of the electric circuit representing the TS and the discharge diameter measurements using a fast intensified charge-coupled device (iCCD) camera. This estimate was compared with ne calculated from the measured Stark broadening of several atomic lines: Hα, N at 746 nm, and O triplet at 777 nm. Good agreement was obtained, although the method based on the plasma resistance is sensitive to an accurate determination of the discharge diameter. We have found that this method is also limited for strongly ionized plasmas. On the other hand, a lower ne detection limit can be obtained by this method than from the Stark broadening of atomic lines.

ICCD Camera Imaging of Discharges in Porous Ceramics

The microdischarges generated inside porous ceramics represent a novel way to create stable atmospheric pressure plasmas. Hybrid plasma-catalytic system utilizing ceramics loaded with catalysts may be very effective for flue gas treatment. This paper presents the images of the discharges in porous ceramics generated by an ac high voltage and visualized by intensified charge-couples device (ICCD) camera system.

Possibilities of Formaldehyde Removal by Discharge Plasma

Removal of formaldehyde by streamer corona discharge was studied experimentally. It was shown the removal efficiency as well as the by-products of the chemical process in the non-thermal plasma of the discharge depend on the initial concentration, gas flow rate, carrier gas, discharge polarity and discharge mode. A combined effect of plasma and catalytic pellets of various materials placed in the discharge reactor was investigated too.© 2003 ASME