Festphasenmikroextraktion (SPME): Eine Alternative zu klassischen Extraktionstechniken

Mit der Arbeit wurde das Ziel verfolgt, rasch durchführbare, leistungsstarke Analysenmethoden zur Bestimmung anthropogener organischer Wasserinhaltsstoffe unter Einsatz der Festphasenmikroextraktion (SPME) in Kombination mit verschiedenen chromatographischen Techniken zu erarbeiten. Die Methoden sollten den Anforderungen genügen, mit denen derzeit ein im Bereich der Wasseranalytik tätiges Laboratorium konfrontiert ist, und insbesondere dazu beitragen, zeitintensive und kostspielige Techniken der Probenvorbereitung durch wirtschaftlichere und umweltfreundlichere Verfahren zu ersetzen. In systematischen Versuchsreihen wurden wichtige Einflußgrößen (pH-Wert, Temperatur, Fasertyp, Extraktionszeit, Salzzugabe, Rührgeschwindigkeit, GC-Bedingungen u.a.) dahingehend optimiert, jeweils akzeptable Arbeitsbedingungen für eine möglichst große Stoffgruppe zu erhalten. In der Regel wurden die Analyten nach Zugabe von Kochsalz aus der Wasserprobe extrahiert. Die Desorption der angereichteren Verbindungen erfolgte dann durch Thermodesorption im Injektor eines Gaschromatographen. Für einige stark polare Stoffe, wurden unterschiedliche Derivatisierungsverfahren erarbeitet, um sie im Anschluß an die Extraktion bei niedrigen pH-Werten einer gaschromatographischen Analyse zugänglich zu machen. Alle Versuche wurden mit Wässern durchgeführt, die mit den zu untersuchenden Stoffen aufgestockt wurden. Im Rahmen der Arbeit gelang die Entwicklung von Analysenverfahren zur Bestimmung von über 60, aus verschiedenen Substanzklassen stammenden Verbindungen. Die erzielten Bestimmungsgrenzen liegen in den meisten Fällen unter dem Grenzwert der Trinkwasserverordnung für PBSM-Wirkstoffe von 0,1 µg/l. Die Kalibriergeraden aller Stoffe zeigen in den gewählten Konzentrationsbereichen ein lineares Verhalten, wobei die Meßwerte außerdem eine hohe Präzision aufweisen. Die erarbeiteten Verfahren sind nicht nur schneller als bestehende, sondern herkömmlichen Techniken auch in ökologischer und ökonomischThe objective of this work was to develop fast and powerful analytical methods for the determination of organic compounds in water using solid phase micro extraction (SPME) and chromatographical techniques. These new methods should replace expensive and time consuming sample preparation techniques with economic and harmless alternatives. Nevertheless they have to meet all the requirements of water suppliers. In several experiments important parameters (pH-value, temperature, type of fibre, extraction time, salt effect, agitation, chromatographic conditions) were investigated and optimized, so that a lot of compounds can be analyzed at once. After adding salt to the sample the analytes were extracted by exposing the fiber into the water. The thermic desorption of the adsorbed compounds took place in the injector of the gas chromatograph where the fiber was put directly after the extraction process. High polar analytes like acidic pharmaceutical compounds were extracted from water at a low pH-value. For the gaschromatographic analysis of these compounds two automated derivatizaton techniques were developed. For all experiments stock solutions of the analytes in drinking water were used. Later the matrix effect was investigated with the use of stock solution in surface water. During this work it was possible to develop sensitive methods for a large amount of compounds. Limits of measurement achieved were mostly below the limiting value of the german regulation for drinking water (0,1/l for each plant protection agent). Linearity and precision of the methods were also very good. The methods developed are fast and superior to conventional methods concerning economic and ecologic aspects. With them cost reduction of analysis is possible, because there is no need for organic solvents. This reduces costs for waste disposal and thus environmental pollution. This is supported by the fact that SPME-Fibers can be used for up to 100 times and so several disposal goods n

La Piezosurgery come metodica alternativa alla strumentazione rotante tradizionale nell'estrazione di ottavi inferiori inclusi. Revisione della letteratura

La presente dissertazione si occupa di esporre la validità della piezosurgery nell'estrazione di ottavi inclusi inferiori come alternativa alla strumentazione rotante tradizionale. Ne vengono illustrati vantaggi e svantaggi con particolare attenzione al tempo impiegato per l'intervento, alla riduzione delle complicanze e al miglioramento del decorso postoperatorio, il tutto sulla base di una revisione sistematica che la letteratura propone su questo argomento corredata dall' esposizione di una serie di casi clinici

Full production cycle, commercial scale culture of salmon in submerged sea-cages with air domes reduces lice infestation, but creates production and welfare challenges

Structural modification of sea cages is continually changing to counter major production issues associated with commercial salmon farming. For example, snorkels and skirts are added to cages to reduce salmon lice infestations, and submerging cages can reduce salmon-lice encounter rates, minimise the effects of storms or avoid other unsuitable sea surface conditions. Unlike snorkels and skirts, the uptake of submerged cages has stalled due to negative effects associated with salmon buoyancy, as salmon require frequent access to the surface to gulp air and fill their swim bladders. Fitting submerged cages with underwater air domes provides an underwater air surface and appears to resolve buoyancy associated issues, but they have not been tested over a full production cycle. Here, we used three 1728 m3 cages submerged to 15 m fitted with air domes and three standard surface cages (i.e. control cages) to grow ~6000 fish per cage from sea transfer (~ 0.2 kg) to harvest size (~5 kg). We tested if growth rates, swimming behaviour, key SWIM (Salmon Welfare Index Model) welfare parameters and lice infestation levels differed between control and submerged cages. Submerged cages had 93% lower lice levels than controls during a large lice pulse event in mid-winter, which was visible through the subsequent lice stages. Swim bladder fullness, swimming behaviour and surface activity rates indicated submerged fish competently used the underwater airdome to maintain neutral buoyancy for the full production cycle. However, after 12 months, harvested mean fish weight was far smaller in submerged (2.8 kg) than control (5 kg) cages and overall mortality 2.5 times higher. Likewise, SWIM welfare scores for eye condition and mouth jaw wounds were worsened in submerged than control cages. The poorer outcomes in submerged cages reflect the suboptimal environmental conditions experienced deeper in the water column, where colder water and/or lower oxygen levels for long periods may have compromised growth. We conclude that while submergence can reduce lice infestation rates, strategies to do so must ensure that fish do not encounter sub-optimal environments for fish growth and welfare.publishedVersio

Consistent melanophore spot patterns allow long-term individual recognition of Atlantic salmon Salmo salar

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'Snorkel' sea lice barrier technology reduces sea lice loads on harvest-sized Atlantic salmon with minimal welfare impacts

-The infestation of farmed Atlantic salmon (Salmo salar) by ectoparasitic sea lice (Lepeophtheirus salmonis) presents a need for new approaches to parasite control. One option is the use of ‘snorkel’ sea lice barrier technology, which restricts salmon from accessing the surface except via a vertical chamber impermeable to sea lice larvae. This prevents the salmon from swimming at the depths where infective sea lice are most abundant. Before snorkels can be implemented in commercial sea-cages, knowledge is required about their effects on salmon welfare and growth. Here, we installed snorkels of 4 m depth into three 12 × 12 × 12 m3 cages, and recorded the lice infestation of stocked fish along with their growth, behaviour, and snout and fin condition over a 12-week period. Three standard sea-cages were utilised for comparison, and all six cages were stocked with ~ 3500 salmon (2.3 ± 0.6 kg). After 3, 6, 9, and 12 weeks, fish in snorkel cages had 65, 24, 43, and 56% lower lice levels than in standard cages, respectively. Salmon in both snorkel and standard cages grew similarly well and we detected little or no adverse effects on fish mortality or welfare. The results indicate that snorkel sea-cage barrier technology provides a promising new tool in parasite management in salmon aquaculture

Maximum Host Survival at Intermediate Parasite Infection Intensities

BACKGROUND: Although parasitism has been acknowledged as an important selective force in the evolution of host life histories, studies of fitness effects of parasites in wild populations have yielded mixed results. One reason for this may be that most studies only test for a linear relationship between infection intensity and host fitness. If resistance to parasites is costly, however, fitness may be reduced both for hosts with low infection intensities (cost of resistance) and high infection intensities (cost of parasitism), such that individuals with intermediate infection intensities have highest fitness. Under this scenario one would expect a non-linear relationship between infection intensity and fitness. METHODOLOGY/PRINCIPAL FINDINGS: Using data from blue tits (Cyanistes caeruleus) in southern Sweden, we investigated the relationship between the intensity of infection of its blood parasite (Haemoproteus majoris) and host survival to the following winter. Presence and intensity of parasite infections were determined by microscopy and confirmed using PCR of a 480 bp section of the cytochrome-b-gene. While a linear model suggested no relationship between parasite intensity and survival (F = 0.01, p = 0.94), a non-linear model showed a significant negative quadratic effect (quadratic parasite intensity: F = 4.65, p = 0.032; linear parasite intensity F = 4.47, p = 0.035). Visualization using the cubic spline technique showed maximum survival at intermediate parasite intensities. CONCLUSIONS/SIGNIFICANCE: Our results indicate that failing to recognize the potential for a non-linear relationship between parasite infection intensity and host fitness may lead to the potentially erroneous conclusion that the parasite is harmless to its host. Here we show that high parasite intensities indeed reduced survival, but this effect was masked by reduced survival for birds heavily suppressing their parasite intensities. Reduced survival among hosts with low parasite intensities suggests costs of controlling parasite infections; however, the nature of such costs remains to be elucidated

Hvordan unngå flytere ved heving av torskemerder

Oppdrettstorsk tåler en trykkreduksjon på maks 40 % dersom en skal være sikker på at svømmeblæren ikke løfter fisken til overflaten med buken i været. Etter en slik reduksjon av trykket bør det gå minst åtte timer før neste reduksjon

The interaction between water currents and salmon swimming behaviour in sea cages

Positioning of sea cages at sites with high water current velocities expose the fish to a largely unknown environmental challenge. In this study we observed the swimming behaviour of Atlantic salmon (Salmo salar L.) at a commercial farm with tidal currents altering between low, moderate and high velocities. At high current velocities the salmon switched from the traditional circular polarized group structure, seen at low and moderate current velocities, to a group structure where all fish kept stations at fixed positions swimming against the current. This type of group behaviour has not been described in sea cages previously. The structural changes could be explained by a preferred swimming speed of salmon spatially restricted in a cage in combination with a behavioural plasticity of the fish