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Evaluating scaling of capillary photo-biofilm reactors for high cell density cultivation of mixed trophies artificial microbial consortia
No full textCapillary biofilm reactors (CBRs) are attractive for growing photoautotrophic bacteria as they allow high cell-density cultivation. Here, we evaluated the CBR system's suitability to grow an artificial consortium composed of Synechocystis sp. PCC 6803 and Pseudomonas sp. VBL120. The impact of reactor material, flow rate, pH, O2, and medium composition on biomass development and long-term biofilm stability at different reactor scales was studied. Silicone was superior over other materials like glass or PVC due to its excellent O2 permeability. High flow rates of 520 μL min−1 prevented biofilm sloughing in 1 m capillary reactors, leading to a 54% higher biomass dry weight combined with the lowest O2 concentration inside the reactor compared to standard operating conditions. Further increase in reactor length to 5 m revealed a limitation in trace elements. Increasing trace elements by a factor of five allowed for complete surface coverage with a biomass dry weight of 36.8 g m−2 and, thus, a successful CBR scale-up by a factor of 25.
Practical application: Cyanobacteria use light energy to upgrade CO2, thereby holding the potential for carbon-neutral production processes. One of the persisting challenges is low cell density due to light limitations and O2 accumulation often occurring in established flat panel or tubular photobioreactors. Compared to planktonic cultures, much higher cell densities (factor 10 to 100) can be obtained in cyanobacterial biofilms. The capillary biofilm reactor (CBR) offers good growth conditions for cyanobacterial biofilms, but its applicability has been shown only on the laboratory scale. Here, a first scale-up study based on sizing up was performed, testing the feasibility of this system for large-scale applications. We demonstrate that by optimizing nutrient supply and flow conditions, the system could be enlarged by factor 25 by enhancing the length of the reactor. This reactor concept, combined with cyanobacterial biofilms and numbering up, holds the potential to be applied as a flexible, carbon-neutral production platform for value-added compounds
Sustained selective attention to chromatic information enhances visuocortical gain at the population level
No full textPrior work in selective attention research has shown that colour-selective
attention enhances neural activity in visuocortical areas sensitive to the
attended colour while suppressing activity in areas sensitive to ignored colours.
However, it is currently unclear whether this effect is limited to attending to
specific colour hues or extends to chromatic information more broadly. To
investigate this question, we used steady-state visual evoked potentials
(ssVEPs) frequency tagging to quantify participants’ visuocortical responses to
specific elements embedded in arrays of flickering, randomly moving mid-
complex patterns. Participants were instructed to attend to either coloured or
greyscale patterns while ignoring the others. We found that attending to either
coloured or greyscale patterns produced robust increases in ssVEP amplitudes
both compared to ignored stimuli and to baseline. There was however no evi-
dence of suppressed responses to ignored patterns. These findings demonstrate
that attentional selection based on the presence or absence of chromatic infor-
mation prompts selectively enhanced visuocortical processing but this selective
amplification is not accompanied by suppression of unattended stimuli. Find-
ings are consistent with theoretical notions that predict strong competition
between specific exemplars within a given feature dimension, such as red or
green, but weak competition between broadly defined stimulus categories,
such as chromatic versus non-chromatic
Systemic Effects of Homoarginine Supplementation on Arginine Metabolizing Enzymes in Rats with Heart Failure with Preserved Ejection Fraction
No full textA restoration of low homoarginine (hArg) levels in obese ZSF1 rats (O-ZSF1) before (S1-ZSF1) and after (S2-ZSF1) the manifestation of heart failure with preserved ejection fraction (HFpEF) did not affect the worsening of cardiac HFpEF characteristics. Here, potential regulation of key enzymes of arginine metabolism in other organs was analyzed. Arginase 2 (ARG2) was reduced >35% in the kidney and small intestine of hArg-supplemented rats compared to O-ZSF1. Glycine amidinotransferase (GATM) was 29% upregulated in the kidneys of S1-ZSF1. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) levels were reduced >50% in the livers of O-ZSF1 but restored in S2-ZSF1 compared to healthy rats (L-ZSF1). In the skeletal muscle, iNOS was lower in O-ZSF1 and further decreased in S1-ZSF1 and S2-ZSF1 compared to L-ZSF1. iNOS levels were lower in the liver of the S2-ZSF1 group but higher in the kidneys of S1-ZSF1 compared to L-ZSF1. Supplementation with hArg in an in vivo HFpEF model resulted in the inhibition of renal ARG2 and an increase in GATM expression. This supplementation might contribute to the stabilization of intestinal iNOS and ARG2 imbalances, thereby enhancing barrier function. Additionally, it may offer protective effects in skeletal muscle by downregulating iNOS. In the conceptualization of hArg supplementation studies, the current disease progression stage as well as organ-specific enzyme regulation should be considered
Assessing trade-offs and competition in the role of biomass for achieving climate targets in the German basic chemicals sector
No full textThis cumulative dissertation examines the role of renewable carbon sources in decarbonising the German chemicals industry in line with the Federal Climate Change Act and the Paris Agreement. The sector currently accounts for roughly four percent of Germany’s territorial greenhouse gas emissions and faces increasing pressure to reduce emissions by 65% by 2030 and reach climate neutrality by 2045. Achieving these goals requires a transition away from fossil carbon towards renewable feedstocks such as biomass, biogenic CO₂, and renewable hydrogen. However, these resources are limited and simultaneously demanded by the energy sector, creating substantial competition and significant opportunity costs for their use in chemical production.
The thesis evaluates the economic and environmental trade-offs involved in allocating scarce renewable resources to the substitution of key fossil-based basic chemicals, including ammonia, methanol, ethylene, and adipic acid. A combined methodological framework is applied that integrates techno-economic assessments, life-cycle greenhouse gas emission analysis, and a mathematical optimisation model. This approach enables the analysis of how renewable chemicals interact with energy-sector technologies and of how system-wide resource constraints influence abatement pathways.
The results indicate that a net-zero-emissions basic chemicals sector by 2050 is technically achievable but economically challenging due to the high production costs of renewable chemicals, primarily driven by the cost of renewable feedstocks. Bio-methanol from forest-residue gasification can become cost-competitive with fossil methanol, whereas renewable routes for adipic acid remain significantly more expensive, and the use of succinic acid as a renewable replacement is limited by both its high costs and the opportunity costs arising from competing biomass applications. The analysis further shows that forest residues, when assessed systemically, often deliver higher value in bioenergy applications than in renewable chemical production.
Under a variety of resource-availability scenarios, the optimisation results suggest that achieving a cost-competitive net-zero basic chemicals sector would require a marginal carbon price of approximately 810 €/tCO₂. This indicates that CO₂ pricing alone is unlikely to drive the widespread adoption of renewable chemical pathways without substantial price increases and strong international coordination on minimum carbon prices. The thesis also highlights the importance of recycling carbon-containing end products at end of life to retain biogenic carbon within material cycles, thereby reducing overall abatement costs.
Overall, the dissertation provides an integrated assessment of renewable resource allocation, technology pathways, and economic trade-offs for decarbonising the German chemicals industry. The findings offer strategic insights for policymakers, industry stakeholders, and researchers working on climate-neutral chemical production and on the broader interplay between biomass, renewable hydrogen, energy systems, and industrial transformation.Diese kumulative Dissertation untersucht die Rolle erneuerbarer Kohlenstoffquellen bei der Dekarbonisierung der deutschen Chemieindustrie im Einklang mit dem Bundes-Klimaschutzgesetz und dem Pariser Abkommen. Der Sektor verursacht derzeit rund vier Prozent der territorialen Treibhausgasemissionen Deutschlands und steht unter zunehmendem Druck, die Emissionen bis 2030 um 65 % zu senken und bis 2045 Klimaneutralität zu erreichen. Zur Erreichung dieser Ziele ist ein Übergang von fossilem Kohlenstoff hin zu erneuerbaren Rohstoffen wie Biomasse, biogenem CO₂ und erneuerbarem Wasserstoff erforderlich. Diese Ressourcen sind jedoch begrenzt und werden parallel vom Energiesektor stark nachgefragt, was zu erheblicher Konkurrenz und hohen Opportunitätskosten für ihren Einsatz in der chemischen Produktion führt.
Die Arbeit bewertet die ökonomischen und ökologischen Zielkonflikte bei der Allokation knapper erneuerbarer Ressourcen zur Substitution zentraler fossiler Grundchemikalien, darunter Ammoniak, Methanol, Ethylen und Adipinsäure. Hierzu wird ein kombiniertes methodisches Rahmenwerk angewendet, das techno-ökonomische Bewertungen, Lebenszyklusanalysen der Treibhausgasemissionen und ein mathematisches Optimierungsmodell integriert. Dies ermöglicht eine systemische Analyse der Wechselwirkungen zwischen erneuerbaren chemischen Pfaden und Energiesystemtechnologien sowie der Auswirkungen übergeordneter Ressourcenrestriktionen auf Emissionsminderungspfade.
Die Ergebnisse zeigen, dass ein klimaneutraler Grundstoffsektor bis 2050 technisch erreichbar ist, wirtschaftlich jedoch erhebliche Herausforderungen bestehen, da die Produktionskosten erneuerbarer Chemikalien vor allem durch hohe Rohstoffkosten geprägt sind. Bio-Methanol aus Waldrestholzvergasung kann kostenkonkurrenzfähig zu fossilem Methanol werden. Dagegen bleiben erneuerbare Routen für Adipinsäure deutlich teurer, und der Einsatz von Bernsteinsäure als erneuerbare Alternative ist sowohl durch hohe Kosten als auch durch Opportunitätskosten aufgrund konkurrierender Biomassenutzungen begrenzt. Darüber hinaus zeigt die Analyse, dass Waldrestholz auf Systemebene häufig einen höheren Wert in bioenergetischen Anwendungen erzielt als in der Produktion erneuerbarer Chemikalien.
Unter verschiedenen Szenarien der Ressourcenverfügbarkeit deutet das Optimierungsmodell darauf hin, dass ein kostenwettbewerbsfähiger klimaneutraler Grundstoffsektor einen marginalen CO₂-Preis von etwa 810 €/tCO₂ erfordern würde. Dies zeigt, dass CO₂-Bepreisung allein wahrscheinlich nicht ausreicht, um eine umfassende Verbreitung erneuerbarer chemischer Pfade anzustoßen, ohne erhebliche Preissteigerungen und eine starke internationale Koordinierung bei Mindest-CO₂-Preisen. Die Dissertation betont zudem die Bedeutung des Recyclings kohlenstoffhaltiger Endprodukte am Lebensende, um biogenen Kohlenstoff in Materialkreisläufen zu halten und die Gesamtkosten der Emissionsminderung zu senken.
Insgesamt bietet die Arbeit eine integrierte Bewertung der Allokation erneuerbarer Ressourcen, technologischer Transformationspfade und ökonomischer Zielkonflikte für die Dekarbonisierung der deutschen Chemieindustrie. Die Ergebnisse liefern strategische Erkenntnisse für politische Entscheidungsträger, Industrievertreter und Forschende im Bereich klimaneutraler chemischer Produktion sowie für das breitere Zusammenspiel von Biomasse, erneuerbarem Wasserstoff, Energiesystemen und industrieller Transformation
Nutrient enrichment alters seasonal β-diversity in global grasslands
No full text1. Intra-annual (i.e. seasonal) temporal niche partitioning is essential to the
maintenance of biodiversity in many plant communities. However, understanding
of how climate and global change drivers such as eutrophication influence
seasonal niche partitioning in plant assemblages remains limited.
2. We used early-season and late-season compositional data collected from 10
grassland sites around the world to explore relationships between climate
variability and intra-annual species segregation (i.e. seasonal β-diversity) and to
assess how nutrient enrichment alters seasonal β-diversity in plant communities.
We then assessed whether changes in seasonal β-diversity in response to nutrient
enrichment are underpinned by species turnover or nestedness and determined
how specific functional groups (i.e. annual forbs, perennial forbs, C3 and C4
graminoids and legumes) respond to eutrophication within and across early and
late sampling dates.
3. We found a positive relationship between intra-annual temperature variability
and seasonal β-diversity but observed no relationship between intra-annual
precipitation variability and seasonal β-diversity. Nutrient enrichment increased
seasonal β-diversity and increased turnover of species between early- and
late-season communities. Nutrient enrichment reduced the abundance of C4
graminoids and legumes within and across sampling timepoints and eliminated
intra-annual differences in these groups. In contrast, nutrient enrichment resulted
in seasonal differences in C3 graminoids, which were not observed in control
conditions and increased abundance of C3 graminoids and annual forbs within
and across early and late sampling dates.
4. Synthesis: Our understanding of how grasslands respond to various components
of global change is primarily based on studies that document community changes
at inter-annual scales. Using early- season and late-season compositional data
from 10 grassland sites around the world, we show that nutrient enrichment in-
creases seasonal β-diversity and alters intra-annual dynamics of specific func-
tional groups in unique ways
Crystallizability of Free and Tethered Chains in Nanometer-Sized Droplets
No full textConfining polymers to nanometric sizes often interferes with the
characteristic length scales of structure formation and thus significantly alters
crystallization or nucleation behavior at the nanoscale. To investigate such
effects in nanometric samples, past studies relied either on heavily
constraining environments like block copolymer mesophases or on deposited
droplets that exhibit significant variation in size, thus requiring extensive
analysis to assign size classes. This studypresents a novel method to create
nanometer-sized polymer droplets of narrow volume distribution and to study
their dynamic and thermodynamic behavior using the change in orientational
polarization. A combination of gold-nanoparticle deposition with a grafting-to
reaction and a nanostructured electrode setup enabled the measurement of
poly--caprolactone (PCL) droplets consisting of ten chains on average for a
relatively small molecular weight. Distinct crystallization and melting
signatures in spin-cast droplets demonstrate the sensitivity of this approach.
In contrast, the grafted aggregates exhibit no signs of crystallization, which is
attributed to considerable constraints in this configuration, like limited chain
motion or too wide chain spacing. Nevertheless, the presented setup is
capable of studying ensembles of individualized (macro-) molecules
Biomarker profiles in heart failure with preserved vs. reduced ejection fraction: results from the DIAST-CHF study
No full textAims: Chronic heart failure (HF) is a common disease and one of the leading causes of death worldwide. Heart failure with preserved ejection fraction (HFpEF) and with reduced ejection fraction (HFrEF) are different diseases with distinct as well as comparable pathophysiologies and diverse responses to therapeutic agents. We aimed to identify possible pathobiochemical signalling pathways and biomarkers in HFpEF and HFrEF by using a broad proteomic approach.
Methods and results: A total of 180 biomarkers in the plasma of a representative subgroup (71 years old) of HFpEF (70% female) with a left ventricular ejection fraction (LVEF) ≥ 50% and HFrEF (18% female) with an LVEF ≤ 40% patients (n = 127) from the Prevalence and Clinical Course of Diastolic Dysfunction and Diastolic Heart Failure (DIAST-CHF) trial were examined and compared with a healthy control group (n = 40; 48% female). We were able to identify 35 proteins that were expressed significantly different in both HF groups compared with the control group. We determine 29 unique proteins expressed in HFpEF and 33 unique proteins in HFrEF. Significantly up-regulated trefoil factor 3 (TFF3) and down-regulated contactin-1 could be identified as previously unknown biomarkers for HF. However, TFF3 is also a predictive factor for the occurrence of a cardiovascular event in HFpEF patients. In HFpEF, serine protease 27 was found at reduced levels for the first time, which could offer a new therapeutic target. Additionally, network analyses showed a special role of platelet-derived growth factor subunit A, Dickkopf-related protein 1, and tumour necrosis factor receptor superfamily member 6 in HFpEF patients, whereas perlecan and junctional adhesion molecule A stood out in the HFrEF group. Overall, signalling pathways of metabolic processes, cellular stress, and iron metabolism seemed to be important for HFrEF, whereas for HFpEF, oxygen stress, haemostasis, cell renewal, cell migration, and cell proliferation are in the foreground.
Conclusions: The identified proteins and signalling pathways offer new therapeutic and diagnostic approaches for patients with chronic HF
On How to Be Liked in First Encounters: The Effects of Agentic and Communal Behaviors on Popularity and Unique Liking
No full textWhen meeting other people for the first time, how should one behave in order to be liked? We investigated the
effects of agentic and communal behaviors on two forms of being liked: popularity (being generally liked by others)
and unique liking (being uniquely liked by specific interaction partners). In a round-robin study, 139 unacquainted
German adults had dyadic conversations and provided liking ratings afterward. The conversations were recorded
on video, and four agentic behaviors (leading, dominant, confident, boastful) and four communal behaviors (polite,
benevolent, warm, friendly) were each rated by trained observers. Participants who generally showed agentic and
communal behavior were also generally liked (popularity). When participants’ level of communal, but not agentic,
behavior exceeded their personal standards during an interaction, they were particularly well-liked by the respective
interaction partner (unique liking). The behavioral predictors of being liked thus differ, depending on whether one
focuses on popularity or unique liking
Ternary magnesium gallides: synthesis, crystal chemistry and properties of CaMgGa, SrMgGa, BaMgGa and YbMgGa
No full textThe gallides CaMgGa, SrMgGa, BaMgGa and YbMgGa were
synthesized from the elements in sealed tantalum ampoules in
muffle furnaces. The phase purity of the samples was checked
by powder X-ray diffraction. CaMgGa and YbMgGa crystallize
with the ZrNiAl type structure, space group P62m, whereas
SrMgGa and BaMgGa adopt an ordering variant of the Cu2Sb/
PbFCl type, space group P4/nmm. The structures of SrMg0.884(7)-
Ga1.116(7) (a=459.23(9), c=792.43(12) pm, wR2=0.0371, 226 F2
values, 11 variables) and YbMgGa (a=774.55(7), c=411.95(4)
pm, wR2=0.0329, 342 F2 values, 15 variables) were refined from
single crystal X-ray diffractometer data. Refinement of the
occupancy parameters indicated a small degree of Mg/Ga
mixing on the 2a site for the strontium compound. The [MgGa]
substructures in both compounds are composed of condensed
Mg@Ga4 tetrahedra with 4×287 pm Mg Ga in SrMg0.884Ga1.116 vs
2×282 and 2×296 pm in YbMgGa. The SrMgGa structure has a
stacking of layers of edge-sharing Mg@Ga4 and Sr4 tetrahedra.
Electronic structure calculations indicate a net charge transfer
from strontium and magnesium to gallium. YbMgGa completes
the series of REMgGa gallides. Temperature dependent magnetic
susceptibility studies reveal weak Pauli paramagnetism,
confirming divalent ytterbium
Stafiba: A STAT5-Selective Small-Molecule Inhibitor
No full textThe transcription factors STAT5a and STAT5b are constitutively active in many human tumors. Combined inhibition of both STAT5 proteins is a valuable approach with promising applications in tumor biology. We recently reported resorcinol bisphosphate as a moderately active inhibitor of the protein-protein interaction domains, the SH2 domains, of both STAT5a and STAT5b. Here, we describe the development of resorcinol bisphosphate to Stafiba, a phosphatase-stable inhibitor of STAT5a and STAT5b with activity in the low micromolar concentration range. Our data provide insights into the structure-activity relationships of resorcinol bisphosphates and the corresponding bisphosphonates for use as inhibitors of both STAT5a and STAT5b