Microplastics in Limnic Ecosystems - Investigation of Biological Fate and Effects of Microplastic Particles and Associated Contaminants in Zebrafish (Danio rerio)-

Given the continually increasing global polymer production, environmental pollution from plastic debris has been widely perceived as an ecological threat with potentially adverse (eco-)toxicological impacts on various species and ecosystems. Especially small fragments of plastic debris measuring 1 ≤ 1000 µm in size − so-called microplastics (MPs) − can pose a risk to biota by physical or chemical hazards due to ingestion, sorption and transfer of anthropogenic environmental pollutants (e.g., pesticides, polycyclic aromatic hydrocarbons, pharmaceuticals). In recent years, there has been extensive research on the impact of streams and rivers as main entry routes for MPs into the marine environment. However, the evidence of adverse effects caused by the intake of MPs and the transfer of contaminants sorbed to MPs into freshwater ecosystems is still not conclusively documented. Therefore, this thesis addressed the impact of microplastic particles in limnic ecosystems by investigating the biological fate and effects of MPs and associated anthropogenic pollutants on different life stages of zebrafish (Danio rerio). To this end, effects of two common environmental pollutants (benzo(k)fluoranthene, chlorpyrifos) and two synthetic polymers (polystyrene, polymethyl methacrylate) were investigated with regard to alterations of complementary biomarkers during acute and chronic exposure, as well as the trophic transfer of MPs and MP-sorbed contaminants from invertebrate organisms to zebrafish and acute toxic effects of MPs pre-exposed in a natural aquatic ecosystem. Overall, the sorption of both anthropogenic pollutants to MPs could be confirmed under various exposure scenarios. In contrast to recent study results, no adverse effects were observed when zebrafish were exposed to clean, pristine polystyrene and polymethyl methacrylate. The ingestion of MPs was documented in the gastrointestinal tract of zebrafish and did not induce any physiological impairment. The uptake of both pollutants was verified for all investigated species by GC-MS and fluorescence measurements. In the acute exposure scenario using the fish embryo toxicity test (FET), zebrafish embryos displayed sublethal effects and morphological deformities related to the underlying mode of action of benzo(k)fluoranthene and chlorpyrifos. Exposure to MP-associated contaminants significantly reduced malformations and attenuated biomarker responses of acetylcholine esterase activity and CYP450 induction and hence indicated a reduced bioavailability of both pollutants for zebrafish embryos. Chronic exposure of adult zebrafish to both types of MPs and pollutants was designed to assess the potential impact of long-term exposure and possible bioaccumulation of these contaminants of emerging concern. However, exposure to MP-sorbed pollutants failed to alter biomarker responses over the prolonged experimental period. In addition, a novel approach was applied to monitor the uptake of benzo(k)fluoranthene in the intestinal epithelium using confocal laser scanning microscopy. However, no significant bioaccumulation or biotransformation of benzo(k)fluoranthene and chlorpyrifos in brain and liver tissue could be demonstrated using ultra performance liquid chromatography coupled with fluorescence detection and with a high-resolution mass spectrometer (UPLC-FLD/HRMS). In order to address the possible vector effects of MPs, the transfer of benzo(k)fluoranthene and polymethyl methacrylate particles in a simplified limnic food web were investigated, consisting of zooplankton (Daphnia magna), sediment-dwelling invertebrates (Chironomus riparius larvae) and zebrafish as highlevel predator. However, the trophic transfer of benzo(k)fluoranthene via MPs could not be confirmed by a combination of highly sensitive fluorescence tracking using CLSM, hepatic CYP450 induction, and advanced chemical-analytical methods. To account for the demand for environmentally relevant exposure scenarios and to improve risk assessment of MPs, a mixture of the most commonly used synthetic polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride) was exposed in a well-monitored surface water body. To evaluate the potential transfer of hazardous pollutants under natural conditions, the toxicity of the MP mixture was assessed in terms of acute toxic effects (FET), potential neurotoxic effects (AChE activity, larval visual motor response test) and effects of dioxin-like substances (EROD assay) using zebrafish embryos. In conclusion, the exposed MP mixture did not elicit significantly different effects than the natural particles from sediment and suspended matter samples. Eventually, it could only be confirmed that MPs could act as carriers for environmental contaminants following ingestion by various organisms. However, increased deleterious effects of MP-sorbed contaminants on various sensitive life stages of zebrafish could not be corroborated by acute or prolonged exposure, trophic transfer, or natural exposure. The findings suggest that the sorption of pollutants to MPs is more likely to reduce the bioavailability as a result of slow desorption within the organism. Although, MPs offer an alternative exposure route for aquatic organisms via ingestion. Even chronic exposure at environmentally relevant concentrations did not induce bioaccumulation of both highly lipophilic substances in zebrafish tissues. Lastly, the sorption behavior of MPs under realistic environmental exposure conditions was more likely to approximate the behavior of natural particles. Consequently, MPs might pose only a limited risk to limnic communities, especially with regard to the comparatively small fraction of plastic particles in freshwater ecosystems compared to the multitude of naturally occurring (a)biotic particles

Water as a Refrigerant in Centrifugal Compressor Cooling Systems for Industrial Applications

As a consequence of the F-gas regulation R404A is no longer a viable option for commercial refrigeration applications. Therefore, this paper focuses on natural refrigerants. There are a few alternatives like carbon dioxide, which has an efficiency loss with increasing environment temperatures. A promising option is the combination of a carbon dioxide process with a chiller using water as refrigerant. Two types of interconnection seem to make energy sense. On the one hand, the interconnection as a cascade, whereby the complete heat of condensation is given off to the water chiller, on the other hand the subcooling of transcritical CO2 after the gas cooler. Both types of interconnection result in optimized operating parameters for the CO2 process. These are examined more closely, and finally, the annual COP values are compared with the standard systems

Efficiency Enhancement By Subcooling The Carbon Dioxide Process With Water As Refrigerant

As a consequence of the F-Gas regulation R404A is no longer an option for commercial refrigeration applications. Therefore, this paper focuses on natural refrigerants. There are a few options like carbon dioxide, which has an efficiency loss with increasing ambient temperatures. A promising option is subcooling of the carbon dioxide process with a chiller using water as the refrigerant. This will result in a new optimized high pressure of the carbon dioxide process depending on the ambient temperature. Finally the annual COP values of the standard transcritical and subcooled system will be discussed

First-line treatment of metastatic breast cancer with the use of liposomal doxorubicin (Myocet®) in a female patient with ischaemic heart disease and cardiac dysrhythmia

Antracykliny są lekami o dużej skuteczności w leczeniu chorych z rozsianym rakiem piersi. Część pacjentek obciążonych kardiologicznie posiada przeciwwskazania do zastosowania tego typu leczenia, ze względu na ryzyko rozwinięcia się kardiotoksyczności. Opisany przypadek dotyczy pacjentki z chorobą niedokrwienną serca i zaburzeniami rytmu, u której zastosowano leczenie doksorubicyną liposomalną w pierwszej linii leczenia rozsianego raka piersi. Onkol. Prak. Klin. 2010; supl. A: A31–A32Anthracyclines are drugs characterised by high efficacy in the treatment of patients with metastatic breast cancer. However, this therapeutic approach is contraindicated in some of the female patients with a history of heart disease in view of the risk of cardiotoxicity. A case report is presented of a female patient with ischaemic heart disease and cardiac dysrhythmia receiving liposomal doxorubicin as part of the first-line treatment of metastatic breast cancer. Onkol. Prak. Klin. 2010; supl. A: A31–A3

eRecruiting als zentrales Element einer modernen Personalbeschaffung

eRecruiting, Employer Branding, Personalmarketing, Social Communit

Chemotherapy based on liposomal doxorubicin (Myocet®) in metastatic breast cancer after prior first-line treatment with anthracycline

Metastatic at diagnosis breast cancer occurs increasingly rarely, yet it remains a significant therapeutic problem. The abundance of available systemic treatment regimens and the possibility of applying different therapies pose before the physician a difficult task of employing the optimal treatment approach. At the same time, good therapeutic results and ever better tolerance for systemic treatment lead to female patients receiving a large number of chemotherapy lines. One of the options in recent years is the treatment with the use of liposomal doxorubicin. A case report is presented of a female patient who received secondline therapy with liposomal doxorubicin in combination with cyclophosphamide after prior treatment with anthracyclines. Onkol. Prak. Klin. 2010; supl. A: A28–A30Rozsiany w chwili rozpoznania rak piersi zdarza się coraz rzadziej, jednak ciągle stanowi poważny problem terapeutyczny. Mnogość dostępnych schematów leczenia systemowego i możliwość zastosowania różnych terapii stawiają przed lekarzem trudne zadanie zastosowania optymalnego schematu leczenia. Jednocześnie dobre efekty leczenia oraz coraz lepsza tolerancja leczenia systemowego powodują, że pacjentki są leczone wieloma liniami chemioterapii. Jedną z propozycji ostatnich lat jest leczenie z zastosowaniem liposomalnej doksorubicyny. Opisano przypadek pacjentki, u której przeprowadzono leczenie drugiej linii z zastosowaniem doksorubicyny liposomalnej w połączeniu z cyklofosfamidem po uprzednim leczeniu antracyklinami. Onkol. Prak. Klin. 2010; supl. A: A28–A3

Concept for a Time-of-Flight Small Angle Neutron Scattering Instrument at the European Spallation Source

A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards um and tens of um, respectively. Two 1m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.Comment: 18 pages, 10 figure

Men of order and command. The teacher in Heinrich Mann's "Professor Unrat" and Jurek Becker's "Schlaflose Tage"

Der Lehrerstand ist gegenwärtig, ungeachtet seines öffentlichen Ansehens, ein erfolgversprechendes Thema in Literatur und Film: In besonderem Maße erscheinen Lehrerfiguren geeignet, aktuelle Missstände und Konflikte aufzuzeigen. So ist das dichterische Interesse für das Sujet auch kein neues Phänomen – insbesondere in der wechselvollen Geschichte des 20. Jahrhunderts ist wiederholt eine verstärkte Produktion von Werken über Schule und ihre Akteure zu verzeichnen. Plausibel wird diese Beobachtung, berücksichtigt man den besonderen beruflichen Auftrag des Lehrers: Als offizieller Repräsentant des jeweils herrschenden Systems bekommt er gesellschaftliche Wandlungsprozesse unmittelbar zu spüren und ist gezwungen, in einem konstanten Spannungsfeld zwischen Anspruch und Möglichkeit zu agieren. Den poetischen Mitteln der Literatur ist es vorbehalten, eine solch zerrissene Figur zur Darstellung einer widersprüchlichen Wirklichkeit heranzuziehen. Zwei exemplarische literarische Analysen aus unterschiedlichen Phasen des letzten Jahrhunderts gehen dieser These nach: Die Lehrer in Heinrich Manns Professor Unrat sowie Jurek Beckers Schlaflose Tage stehen als Sinnbilder für gesellschaftliche Umbrüche, die sich in der Identitätsproblematik und im anschließenden Ausbruch der Protagonisten bereits ankündigen

Chronic meningococcemia in a 16-year-old boy: a case report

Herein, we present a case of meningococcal disease in a patient presenting with of a three-week history of fever, cutaneous vasculitis and joint pain, in whom chronic meningococcemia was retained as presumptive diagnosis, after the disease evolved towards meningitis. This unusual case illustrates the great heterogeneity in possible clinical presentations of Neisseria meningitidis infections and underlines that diagnosis should always be evocated when facing the triad of fever, vasculitic skin eruption and big joints arthralgia, in a person in otherwise good general condition