Deutsch-russische Zusammenarbeit in der Arktis

Seit 1993 wird im Rahmen zweier vom BMBF geförderter Projekte die Laptevsee in der russischen Arktis (nicht nur) biologisch untersucht. Von 1993 - 1997 wurde das am Institut für Polarökologie angesiedelte Projekt. Deutsch - Russische Untersuchungen zur Ökologie der Randmeere der Eurasischen Arktis" mit insgesamt 1,5 Mio. DM gefördert. In einer zweiten Phase, die 199 8 begann, wurde die biologische Forschung in der Laptevsee mit veränderten Forschungsschwerpunkten als Teilprojekt in das Verbundvorhaben "System Laptevsee 2000" eingebettet. Im folgenden soll ein kurzer Uberblick über die biologischen Forschungsaktivitäten im Rahmen dieser Projekte gegeben werden

Optimization of the Treatment of Squamous Cell Carcinoma Cells by Combining Photodynamic Therapy with Cold Atmospheric Plasma

Actinic keratosis (AK) is characterized by a reddish or occasionally skin-toned rough patch on sun-damaged skin, and it is regarded as a precursor to squamous cell carcinoma (SCC). Photodynamic therapy (PDT), utilizing 5-aminolevulinic acid (ALA) along with red light, is a recognized treatment option for AK that is limited by the penetration depth of light and the distribution of the photosensitizer into the skin. Cold atmospheric plasma (CAP) is a partially ionized gas with permeability-enhancing and anti-cancer properties. This study analyzed, in vitro, whether a combined treatment of CAP and ALA-PDT may improve the efficacy of the treatment. In addition, the effect of the application sequence of ALA and CAP was investigated using in vitro assays and the molecular characterization of human oral SCC cell lines (SCC-9, SCC-15, SCC-111), human cutaneous SCC cell lines (SCL-1, SCL-2, A431), and normal human epidermal keratinocytes (HEKn). The anti-tumor effect was determined by migration, invasion, and apoptosis assays and supported the improved efficacy of ALA-PDT in combination with CAP. However, the application sequence ALA-CAP–red light seems to be more efficacious than CAP-ALA–red light, which is probably due to increased intracellular ROS levels when ALA is applied first, followed by CAP and red light treatment. Furthermore, the expression of apoptosis- and senescence-related molecules (caspase-3, -6, -9, p16 INK4a , p21 CIP1 ) was increased, and different genes of the junctional network (ZO-1, CX31, CLDN1, CTNNB1) were induced after the combined treatment of CAP plus ALA-PDT. HEKn, however, were much less affected than SCC cells. Overall, the results show that CAP may improve the anti-tumor effects of conventional ALA-PDT on SCC cells. Whether this combined application is successful in treating AK in vivo has to be carefully examined in follow-up studies.This research was funded by the Wilhelm Sander-Stiftung (project 2023.011.1).Wilhelm Sander-Stiftun

Nitroxide-nitroxide and nitroxide-metal distance measurements in transition metal complexes with two or three paramagnetic centres give access to thermodynamic and kinetic stabilities

AG was supported by the EPSRC funded Centre for Doctoral Training in ‘integrated magnetic resonance’ (EP/J500045/1). BEB is grateful for funding from the European Union (REA 334496). This work was supported by the EPSRC (EP/M024660/1), the DFG (Schwerpunktprogramm 1601) and a Wellcome Trust multiuser equipment grant [099149/Z/12/Z].Fundamentally, the stability of coordination complexes and of templated (bio)macromolecular assemblies depends on the thermodynamic and kinetic properties of the intermediates and final complexes formed. Here, we used pulse EPR (electron paramagnetic resonance) spectroscopy to determine the stabilities of nanoscopic assemblies formed between one or two nitroxide spin-labelled tridentate 2,2′:6′,2′′-terpyridine (tpy) ligands and divalent metal ions (FeII, ZnII, CoII and CuII). In three distinct approaches we exploited (a) the modulation depth of pulsed electron–electron double resonance (PELDOR) experiments in samples with increasing metal-to-ligand ratios, (b) the frequencies of PELDOR under broadband excitation using shaped pulses and (c) the distances recovered from well-resolved PELDOR data in fully deuterated solvents measured at 34 GHz. The results demonstrate that PELDOR is highly sensitive to resolving the stability of templated dimers and allows to readily distinguish anti-cooperative binding (for CuII ions) from cooperative binding (for CoII or FeII ions). In the case of paramagnetic ions (CoII and CuII) the use of broadband PELDOR allowed to identify the cooperativity of binding from the time domain and distance data. By using a second labelled tpy ligand and by mixing two homoleptic complexes of the same metal centre we could probe the kinetic stability on a timescale of tens of seconds. Here, tpy complexes of CuII and ZnII were found to be substitutionally labile, CoII showed very slow exchange and FeII was inert under our conditions. Not only do our chemical models allow studying metal–ligand interactions via PELDOR spectroscopy, the design of our study is directly transferable to (bio)macromolecular systems for determining the kinetic and thermodynamic stabilities underpinning (templated) multimerisation. Considering the limited methods available to obtain direct information on the composition and stability of complex assemblies we believe our approach to be a valuable addition to the armoury of methods currently used to study these systems.PostprintPeer reviewe

Analytical and toxicological aspects of nanomaterials in different product groups: Challenges and opportunities

The widespread integration of engineered nanomaterials into consumer and industrial products creates new challenges and requires innovative approaches in terms of design, testing, reliability, and safety of nanotechnology. The aim of this review article is to give an overview of different product groups in which nanomaterials are present and outline their safety aspects for consumers. Here, release of nanomaterials and related analytical challenges and solutions as well as toxicological considerations, such as dose-metrics, are discussed. Additionally, the utilization of engineered nanomaterials as pharmaceuticals or nutraceuticals to deliver and release cargo molecules is covered. Furthermore, critical pathways for human exposure to nanomaterials, namely inhalation and ingestion, are discussed in the context of risk assessment. Analysis of NMs in food, innovative medicine or food contact materials is discussed. Specific focus is on the presence and release of nanomaterials, including whether nanomaterials can migrate from polymer nanocomposites used in food contact materials. With regard to the toxicology and toxicokinetics of nanomaterials, aspects of dose metrics of inhalation toxicity as well as ingestion toxicology and comparison between in vitro and in vivo conclusions are considered. The definition of dose descriptors to be applied in toxicological testing is emphasized. In relation to potential exposure from different products, opportunities arising from the use of advanced analytical techniques in more unique scenarios such as release of nanomaterials from medical devices such as orthopedic implants are addressed. Alongside higher product performance and complexity, further challenges regarding material characterization and safety, as well as acceptance by the general public are expected

Biografieforschung: theoretische Perspektiven und methodologische Konzepte für eine re-konstruktive Geschlechterforschung

Die Biografieforschung bezeichnet einen komplexen Forschungsansatz, der auf eine lange Geschichte des wissenschaftlichen Interesses an "persönlichen Dokumenten" verweisen kann. Sie ist eine voraussetzungsvolle Forschungsperspektive, die sich in zentralen Aspekten ihres Vorgehens auf Biografien als theoretisches Konzept, als historisch-empirischen Gegenstand und als komplexe methodologische Strategie bezieht. Andere Begriffe, welche oftmals synonym gebraucht, in der Biografieforschung aber systematisch unterschieden werden, sind "Lebensgeschichte" und "Lebenslauf". Die Autorin skizziert die Perspektiven einer rekonstruktiven Geschlechterforschung innerhalb der Biografieforschung, wozu sie auf die Differenzierungen empirischer Forschung, die methodologischen Prinzipien sowie auf Datenerhebung und Datenanalyse eingeht. Sie hebt insbesondere drei Kontextrelationen bei der Interpretation eines biografischen Textes hervor: Biografie, Interaktion, kulturelle Muster und soziale Regeln. Das skizzierte Konzept von Biografieforschung begreift sie als ein offenes Programm, das vielfältige Anknüpfungspunkte zu aktuellen theoretischen Diskussionen in der Geschlechterforschung aufweist. (ICI2

The Big Five Personality Domains and Their Facets: Empirical Relations to Problematic Use of Video Games, Social Media and Alcohol

Relatively common behavioral patterns in adolescence are problematic use of video games (PG), social media (PSMU) or alcohol (PAU). According to theoretical models, personality traits are relevant for Internet-related problematic behaviors. In the present study, associations of the Big Five personality domains and their 15 facets with PG, PSMU and PAU were compared for the first time. Therefore, 492 adolescents (mean age: 16.83 years) were examined with the established Big Five Inventory-2 as well as other standardized questionnaires on PG, PSMU and PAU. For statistical evaluation, correlation analyses were used as bivariate procedures and multiple regression analyses as multivariable procedures. At the personality domain level, consistently in bivariate and multivariate analyses, statistically significant associations between higher Negative Emotionality (Neuroticism) and PG, PSMU and PAU as well as between lower Open-Mindedness and PG and PAU were observed. At the level of facets, higher Anxiety (facet of Negative Emotionality) was related to PG and PSMU as well as lower Aesthetic Sensitivity (facet of Open-Mindedness) and lower Productiveness (facet of Conscientiousness) to PG. Considering the overlap of 95% confidence intervals, very comparable patterns of associations between PG, PSMU and PAU and the Big Five and their facets were observed in adolescence (indicating similarities in etiology)

Effects of Enriched Charcoal as Permanent 0.2% Feed-Additive in Standard and Low-Protein Diets of Male Fattening Turkeys: An On-Farm Study

Wet litter is the most important cause of footpad dermatitis in poultry, this in turn being a highly relevant animal-related welfare indicator. This field study was subdivided into two experiments. In Experiment 1, the standard diet was supplemented by 0.2% enriched charcoal, being a non-specific absorber and therefore might be promising in reducing faecal moisture. In Experiment 2, the experimental group received a reduced crude protein diet during weeks 6–13, combined with a 0.2% enriched charcoal supplementation. The trials were each conducted with two batches on three farms under on-farm conditions. The animals were observed at 6, 10, 14 and 18 weeks of age to collect data on body weight and different health parameters. The mortality and litter samples were analysed after slaughtering. In Experiment 1, performance and health were not affected despite higher dry matter content of the litter. In Experiment 2, the weight of birds receiving the protein-reduced diet was decreased significantly throughout the experiment. However, the slaughter weight did not differ. The mortality was reduced by 0.5% in the experimental group. Therefore, it was concluded that 0.2% of enriched charcoal is not a valuable feed-additive regarding animal health, while temporary protein reduction might have positive effects