Quantenkryptographie als Thema für den Physikunterricht - Vorstellung einer Masterarbeit

Quantenkryptographie ist ein modernes Forschungsgebiet der Physik, welches einen motivierenden Kontext für die Grundkonzepte der Quantenphysik bieten kann. Im Rahmen einer Masterarbeit wurde eine Unterrichtseinheit zur Quantenkryptographie mit Photonen erstellt und an einem Physikkurs der 11. Jahrgangsstufe getestet. Wir stellen die Unterrichtsmaterialien sowie die Ergebnisse von Interviews und Fragebögen vor

Quantenkryptographie als Thema für den Physikunterricht - Vorstellung einer Masterarbeit

Quantenkryptographie ist ein modernes Forschungsgebiet der Physik, welches einen motivierenden Kontext für die Grundkonzepte der Quantenphysik bieten kann. Im Rahmen einer Masterarbeit wurde eine Unterrichtseinheit zur Quantenkryptographie mit Photonen erstellt und an einem Physikkurs der 11. Jahrgangsstufe getestet. Wir stellen die Unterrichtsmaterialien sowie die Ergebnisse von Interviews und Fragebögen vor

Human bone marrow contains high levels of extracellular vesicles with a tissue-specific subtype distribution

Introduction Extracellular vesicles (EV) are shed from a broad variety of cells and play an important role in activation of coagulation, cell to cell interaction and transport of membrane components. They are usually measured as circulating EV in peripheral blood (PB) and other body fluids. However, little is known about the distribution, presence and impact of EV and their sub-populations in bone marrow (BM). In our study, we focused on the analysis of different EV subtypes in human BM as compared to EV subsets in PB. Methods EV in BM and PB from 12 healthy stem cell donors were measured by flow-cytometry using Annexin V and cell-specific antibodies for hematopoietic stem cells, leucocytes, platelets, red blood cells, and endothelial cells. Additionally, concentrations of tissue factor-bearing EV were evaluated. Results High numbers of total EV were present in BM (median value [25-75 percentile]: 14.8 x10(9)/l [8.5-19.3]). Non-significantly lower numbers of total EV were measured in PB (9.2 x10(9)/l [3.8-14.5]). However, distribuation of EV subtypes showed substantial differences between BM and PB: In PB, distribution of EV fractions was similar as previously described. Most EV originated from platelets (93.9%), and only few EV were derived from leucocytes (4.5%), erythrocytes (1.8%), endothelial cells (1.0%), and hematopoietic stem cells (0.7%). In contrast, major fractions of BM-EV were derived from red blood cells or erythropoietic cells (43.2%), followed by megacaryocytes I platelets (27.6%), and by leucocytes as well as their progenitor cells (25,7%);only low EV proportions originated from endothelial cells and hematopoietic stem cells (2.0% and 1.5%, respectively). Similar fractions of tissue factor- bearing EV were found in BM and PB (1.3% and 0.9%). Conculsion Taken together, we describe EV numbers and their subtype distribution in the BM compartment for the first time. The tissue specific EV distribution reflects BM cell composition and favours the idea of a BM-PB barrier existing not only for cells, but also for EV

Methane emission by Camelids

Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.3260.11 L kg21 d21) when compared to literature data on domestic ruminants fed on roughage diets (0.5860.16 L kg21 d21). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7633.9 L kg21 in camelids vs. 86.2612.1 L kg21 in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia’s feral camels corresponds only to 1 to 2% of the methane amount produced by the countries’ domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels

Innovative Techniques and Strategies for a Reliable High-Throughput Genotoxicity Assessment

Damage to DNA is a central mechanism to the initiation of carcinogenesis. As a consequence, precise DNA damage detection is essential for an effective risk assessment of xenobiotics and constitutes a powerful tool for human biomonitoring and early stage cancer risk assessment. Here we highlight four innovative approaches for determining genotoxicity in a reliable and in the future high-throughput manner. In this context, we discuss and evaluate recent improvements to well-established methods and present promising new techniques

Extracellular vesicles in human follicular fluid do not promote coagulation

Body fluids contain extracellular vesicles expressing tissue factor on their surface and serve as an additional trigger for coagulation. During the menstrual cycle ovarian tissue restoration is mandatory and it is unknown whether follicular fluid might provide procoagulant substances. Within an observational study, follicular fluid from women undergoing IVF/intracytoplasmic sperm injection (ICSI) was analysed by fluorescence-activated cell sorting (FACS), electron microscopy, resistive pulse sensing (RPS), nanoparticle-tracking analysis (NTA) and fibrin generation tests (FGT). The presence of extracellular vesicles, especially CD9-positive extracellular vesicles in follicular fluid, was proven. However, clotting tests revealed no procoagulant properties of the detected extracellular vesicle