The primary carbon metabolism in cyanobacteria and its regulation

Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis. Many cyanobacterial strains can live in different trophic modes, ranging from photoautotrophic and heterotrophic to mixotrophic growth. However, the regulatory mechanisms allowing a flexible switch between these lifestyles are poorly understood. As anabolic fixation of CO2 in the Calvin-Benson-Bassham (CBB) cycle and catabolic sugar-degradation pathways share intermediates and enzymatic capacity, a tight regulatory network is required to enable simultaneous opposed metabolic fluxes. The Entner-Doudoroff (ED) pathway was recently predicted as one glycolytic route, which cooperates with other pathways in glycogen breakdown. Despite low carbon flux through the ED pathway, metabolite analyses of mutants deficient in the ED pathway revealed a distinct phenotype pointing at a strong regulatory impact of this route. The small Cp12 protein downregulates the CBB cycle in darkness by inhibiting phosphoribulokinase and glyceraldehyde 3-phosphate dehydrogenase. New results of metabolomic and redox level analyses on strains with Cp12 variants extend the known role of Cp12 regulation towards the acclimation to external glucose supply under diurnal conditions as well as to fluctuations in CO2 levels in the light. Moreover, carbon and nitrogen metabolism are closely linked to maintain an essential C/N homeostasis. The small protein PirC was shown to be an important regulator of phosphoglycerate mutase, which identified this enzyme as central branching point for carbon allocation from CBB cycle towards lower glycolysis. Altered metabolite levels in the mutant ΔpirC during nitrogen starvation experiments confirm this regulatory mechanism. The elucidation of novel mechanisms regulating carbon allocation at crucial metabolic branching points could identify ways for targeted redirection of carbon flow towards desired compounds, and thus help to further establish cyanobacteria as green cell factories for biotechnological applications with concurrent utilization of sunlight and CO2

Changes in compound flood event frequency in northern and central Europe under climate change

The simultaneous occurrence of increased river discharge and high coastal water levels may cause compound flooding. Compound flood events can potentially cause greater damage than the separate occurrence of the underlying extreme events, making them essential for risk assessment. Even though a general increase in the frequency and/or severity of compound flood events is assumed due to climate change, there have been very few studies conducted for larger regions of Europe. Our work, therefore, focuses on the high-resolution analysis of changes in extreme events of coastal water levels, river discharge, and their concurrent appearance at the end of this century in northern and central Europe (2070–2099). For this, we analyze downscaled data sets from two global climate models (GCMs) for the two emissions scenarios RCP2.6 and RCP8.5. First, we compare the historical runs of the downscaled GCMs to historical reconstruction data to investigate if they deliver comparable results for northern and central Europe. Then we study changes in the intensity of extreme events, their number, and the duration of extreme event seasons under climate change. Our analysis shows increases in compound flood events over the whole European domain, mostly due to the rising mean sea level. In some areas, the number of compound flood event days increases by a factor of eight at the end of the current century. This increase is concomitant with an increase in the annual compound flood event season duration. Furthermore, the sea level rise associated with a global warming of 2K will result in double the amounts of compound flood event days for nearly every European river estuary considered

On Key Parameters for the Attractiveness of On-Demand Inter-City Air Mobility

In this paper, we present a globally applicable approach for estimating the potential passenger demand for On- Demand Inter-City Air Mobility based on three different use cases. All of these cases are concerned with pas- sengers who nowadays travel with conventional airlines, and might choose On-Demand Air Mobility (ODAM) as an alternative mode of travel in future. First, we consider the possibility to complement direct connections on low-demand inter-city routes. Second, we analyse the possibility of replacing multi-stop connections, where the origin and destination airports are within a certain range. Third, we take a look at feeder flights from small or regional airports to bigger hubs and vice versa. The approach is then used for estimating the impact of five parameters on the ODAM market size. These are namely air taxi speed, air taxi range, the set of usable airports, a time offset which is added to the flight time of every trip and the availability of alternate airports. We conduct this investigation for four regions: China, Europe, India, and the US and analyse the differences between the various parameters over the different use cases in these regions. The results show that the potential market size differs widely between regions, use cases and parameters. The largest potential market overall can be identified in Europe with approximately 6.7 million PAX and about 582 Million USD revenue per year. For all regions, in total, complementing direct flights attracts most people to use ODAM as an alternative way of transportation. Considering that the value proposition of ODAM is the reduction of travel time, both technical and operational parameters of air taxis show a high impact on the potential market size. Compared to cars, their advantage lies in the higher speed, whereas the absence of schedule delay is the main advantage compared to conventional air travel

Increased risk for thromboembolic events from combination of a gynecologic malignancy with severe acute respiratory syndrome coronavirus 2 infection: a case report

Purpose During the severe acute respiratory syndrome coronavirus 2 pandemic, several patient groups are at particular risk. Mortality is higher among cancer patients and may be increased further by thromboembolic events, which are more common in coronavirus 2019 patients according to recent publications. We discuss the association of gynecologic malignancies, Severe acute respiratory syndrome coronavirus 2, and thromboembolism by reporting a case study and summarizing available literature. Case report A 71-year-old Caucasian patient with ovarian cancer receiving first-line chemotherapy was diagnosed with deep vein thrombosis and pulmonary embolism. Routine screening revealed infection with severe acute respiratory syndrome coronavirus 2 in absence of specific symptoms. After uneventful recovery, oncologic treatment could be continued a few weeks later. Methods We performed a systematic review of the literature on PubMed following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The search included articles ahead of print, published between 1 December 2019 and 1 June 2020. Cross-searches were conducted on all relevant articles. Results We identified five articles meeting the defined criteria, including two retrospective studies, a review, a position paper, as well as a letter to the editor. Conclusion Cancer patients infected with severe acute respiratory syndrome coronavirus 2 have a relatively poor outcome, which may partially be due to a higher rate of thromboembolic events. Thromboprophylaxis is recommended, and scoring systems are helpful in early detection. In cancer patients with severe acute respiratory syndrome coronavirus 2, individual risk for thromboembolic events should be taken into account when considering interruption versus continuation of antitumoral therapy. However, further data and studies are required

Improving the zT value of thermoelectrics by nanostructuring: Tuning the nanoparticle morphology of Sb2Te3 by using ionic liquids

A systematic study on the microwave-assisted thermolysis of the single source precursor (Et2Sb)2Te (1) in different asymmetric 1-alkyl-3-methylimidazolium- and symmetric 1,3-dialkylimidazolium-based ionic liquids (ILs) reveals the distinctive role of both the anion and the cation in tuning the morphology and microstructure of the resulting Sb2Te3 nanoparticles as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). A comparison of the electrical and thermal conductivities as well as the Seebeck coefficient of the Sb2Te3 nanoparticles obtained from different ILs reveals the strong influence of the specific IL, from which C4mimI was identified as the best solvent, on the thermoelectric properties of as-prepared nanosized Sb2Te3. This work provides design guidelines for ILs, which allow the synthesis of nanostructured thermoelectrics with improved performances

Analysis and optimization of volume diffusors

In contrast to imaging optics diffusors are typically used to achieve homogeneous luminance distributions for display and lighting applications. For example, LEDs are nearly point sources and therefore optical beam shaping components are needed. Optical diffusors in reflection and transmission are commonly used for additional luminance homogenization. However, a detailed quantitative understanding and numerical description of their optical performance are very unconfident or still unclear. In this contribution we focus on volume diffusors and present results on three types of particle-matrix-material combinations. The measured straylight distributions are compared to theoretical predictions and show good agreement. From these results optimized material parameters can be derived in order to get improved volume diffusers for tailored luminance distributions

Towards process-informed bias correction of climate change simulations

Biases in climate model simulations introduce biases in subsequent impact simulations. Therefore, bias correction methods are operationally used to post-process regional climate projections. However, many problems have been identified, and some researchers question the very basis of the approach. Here we demonstrate that a typical cross-validation is unable to identify improper use of bias correction. Several examples show the limited ability of bias correction to correct and to downscale variability, and demonstrate that bias correction can cause implausible climate change signals. Bias correction cannot overcome major model errors, and naive application might result in ill-informed adaptation decisions. We conclude with a list of recommendations and suggestions for future research to reduce, post-process, and cope with climate model biases