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The freeze-thaw behaviour of bonded fasteners in concrete is assessed according to the European Assessment Document 330499-01-0601 with freeze-thaw condition tests, which include 50 temperature cycles with a duration of 24 h between −20 °C and +20 °C on constantly loaded anchors. It is assumed that one cycle is equivalent to the temperature difference, which a bonded fastener undergoes in one year. Based on an analysis of a 28-year time series of air temperature data for Austria respecting the Alpine region, a modified test protocol with a temperature amplitude of 65 °C between −20 °C and +45 °C is compiled without a predefinition of the number of cycles, in order to simulate temperature differences that occur under real climatic conditions. The experimental test results obtained for both test procedures demonstrate that the stabilization of the displacements for the modified test series occurred after 185 temperature cycles, compared to the 50 cycles for the standard method. This means that an increase in the temperature amplitude of 25 °C in the higher temperature range leads to an approximately 3.5 times higher number of required temperature cycles until displacement stabilization is reached. It is concluded that the definition of the used temperature range for freeze-thaw testing in conjunction with climatic data should be critically considered, in order to possibly adapt pure freeze-thaw tests towards experiments that take into account real annual temperature differences.

The interaction between monocytes and endothelial cells in inflammation is central to chemoattraction, adhesion, and transendothelial migration. Key players, such as selectins and their ligands, integrins, and other adhesion molecules, and their functions in these processes are well studied. Toll-like receptor 2 (TLR2), expressed in monocytes, is critical for sensing invading pathogens and initiating a rapid and effective immune response. However, the extended role of TLR2 in monocyte adhesion and migration has only been partially elucidated. To address this question, we performed several functional cell-based assays using monocyte-like wild type (WT), TLR2 knock-out (KO), and TLR2 knock-in (KI) THP-1 cells. We found that TLR2 promotes the faster and stronger adhesion of monocytes to the endothelium and a more intense endothelial barrier disruption after endothelial activation. In addition, we performed quantitative mass spectrometry, STRING protein analysis, and RT-qPCR, which not only revealed the association of TLR2 with specific integrins but also uncovered novel proteins affected by TLR2. In conclusion, we show that unstimulated TLR2 influences cell adhesion, endothelial barrier disruption, migration, and actin polymerization.

In endothelial cells (ECs), stimulation of Toll-like receptor 4 (TLR4) by the endotoxin lipopolysaccharide (LPS) induces the release of diverse pro-inflammatory mediators, beneficial in controlling bacterial infections. However, their systemic secretion is a main driver of sepsis and chronic inflammatory diseases. Since distinct and rapid induction of TLR4 signaling is difficult to achieve with LPS due to the specific and non-specific affinity to other surface molecules and receptors, we engineered new light-oxygen-voltage-sensing (LOV)-domain-based optogenetic endothelial cell lines (opto-TLR4-LOV LECs and opto-TLR4-LOV HUVECs) that allow fast, precise temporal, and reversible activation of TLR4 signaling pathways. Using quantitative mass-spectrometry, RT-qPCR, and Western blot analysis, we show that pro-inflammatory proteins were not only expressed differently, but also had a different time course when the cells were stimulated with light or LPS. Additional functional assays demonstrated that light induction promoted chemotaxis of THP-1 cells, disruption of the EC monolayer and transmigration. In contrast, ECs incorporating a truncated version of the TLR4 extracellular domain (opto-TLR4 ΔECD2-LOV LECs) revealed high basal activity with fast depletion of the cell signaling system upon illumination. We conclude that the established optogenetic cell lines are well suited to induce rapid and precise photoactivation of TLR4, allowing receptor-specific studies.

Quercetin, a dietary flavonoid found in fruits and vegetables, has been described as a substance with many anti-cancer properties in a variety of preclinical investigations. In the present study, we demonstrate that 2D and 3D melanoma models exhibit not only different sensitivities to quercetin, but also opposite, cancer-promoting effects when metastatic melanoma spheroids are treated with quercetin. Higher concentrations of quercetin reduce melanoma growth in three tested cell lines, whereas low concentrations induce the opposite effect in metastatic melanoma spheroids but not in the non-metastatic cell line. High (>12.5 µM) or low (0.4 µM), whereas in 3D spheroids apoptotic cells, caspase 3 activity can only be detected in concentrations ≥12.5 µM. Further, we show that the tumor promoting or repressing effect in the 3D metastatic melanoma spheroids are likely to be elicited by a precisely controlled regulation of Nrf2/ARE-mediated cytoprotective genes, as well as ERK and NF-κB phosphorylation. According to the results obtained here, further studies are needed to better characterize the mechanisms of action underlying the pro- and anti-carcinogenic effects of quercetin on human melanomas.

In long-lasting mass concrete structures the desired material properties of the concrete mix to realize a durable concrete and a concrete surface without cracks conflict with each other. The requirement of concrete with high durability leads to high thermal energy release and therefore, as another consequence, to high crack risk. Crack reduction is achieved by use of concrete with low hydration energy, which on the other hand leads to a decrease in concrete durability. Besides from optimized base materials and concrete technology, a gradient material distribution in the cross-section could reduce the problem since durable concrete is needed near the surface and the requirement of low-hydration energy is located in the center of the member. A simplified model is used to investigate the possible effect of a gradient concrete material distribution in mass concrete structures on crack reduction. The results of the analysis show that gradient concrete might contribute to lowering the constraint stresses and therefore the crack risk during concrete hardening.