500 Naturwissenschaften und Mathematik
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This research analyzes the gender dynamics that have influenced natural resource management in the rural communities of La Ferrería and El Nayar, Durango, Mexico, over the past 50 years. Using a theoretical framework based on gender perspective, intersectionality, and rural systems theory, the study examines how social change, globalization, and the new rurality have transformed gender roles and access to natural resources.
Through qualitative methods such as participant observation, semi-structured interviews, life histories, and documentary research, this study identifies the progressive loss of traditional knowledge and the increasing urbanization of rural life. The results reveal that although women have gained greater participation in decision-making processes, structural barriers continue to limit their access to land and resource management. In addition, changing generational perspectives, particularly among participants aged 18 to 24, indicate a growing disengagement from traditional agricultural practices in favor of technical and academic approaches.
This study highlights the urgent need to integrate gender perspectives into rural development policies, promoting sustainable and equitable resource management while preserving ancestral knowledge. The research underscores the importance of revaluing rural work to ensure long-term food security and maintain cultural ties to the land.
Key words: Gender perspective, natural resource management, new rurality, traditional knowledge, rural development.
This document serves as a comprehensive compendium of Nature-based Solutions (NbS) that are vital for enhancing water-sensitive structures and combating environmental changes in South-East Asia (SEA). It provides a framework to address a spectrum of social, economic, and environmental challenges by offering essential ecosystem services. The Compendium defines categories and features to better describe problems, propose solutions (NbSs), and outline how these solutions will achieve their targets through ecosystem services.
This work presents a software-based approach for robust feature tracking of funduscopy images. In our specific application, it is utilized in a scannerless linear optical coherence tomography system, where both natural and directed eye movements are used to scan the retina. The approach developed includes a fast, contrast-enhancing video preprocessing step. Additional filtering highlights edges and details, enhancing the visibility of blood vessels and the optic disc. Reflections are removed, both those arising from the funduscopy setup itself and non-stationary reflections caused by the cornea or an intraocular lens. A state-of-the-art feature detector and descriptor is used to identify and characterize distinctive image regions. Subsequent feature matching and filtering include additional criteria to enhance robustness against outliers and false detections. From these final matches, homographies are calculated, allowing the derivation of relative movements and absolute positions. The results demonstrate real-time processing with high detection rates and minimal misdetections. This performance is maintained even in the presence of poor contrast and non-stationary reflections in the original video stream. While the tracking is optimized for our application, it is also applicable to other domains, such as optimizing the alignment of retinal images, generating wide-field panorama images from individual frames, or characterizing eye movements.
Surface conductivity can have a significant impact on the determination of the zeta potential, but it is normally not accounted for when applying the Helmholtz-Smoluchowski or Henry models. In this study, we investigate concentrated polymer dispersions using electroacoustics and both standard models. We also pay particular attention to the influence of surface conductivity, which is characterized by conductivity measurements of the dispersion and dispersion medium. The Dukhin number as a measure of surface conductivity is calculated according to Maxwell–Wagner-O’Konski theory. Zeta potentials were determined by means of colloid vibration current (CVI) and electrophoretic light scattering (ELS) methods. It has been found that neglecting surface conductivity in standard electrokinetic models can lead to large measurement errors of up to 100% with increasing particle volume fraction. In this study, the surface conductivity is now correctly taken into account by using the conductivities of the dispersion and the dispersion medium. Alternatively, this influence can also be considered using the Dukhin number. The zeta potentials resulting from the CVI measurement are then in excellent agreement with ELS reference measurements over a wide volume fraction range.
N-Acyl-amino acids can act as mild biobased surfactants, which are used, e.g., in baby shampoos. However, their chemical synthesis needs acyl chlorides and does not meet sustainability criteria. Thus, the identification of biocatalysts to develop greener synthesis routes is desirable. We describe a novel aminoacylase from Paraburkholderia monticola DSM 100849 (PmAcy) which was identified, cloned, and evaluated for its N-acyl-amino acid synthesis potential. Soluble protein was obtained by expression in lactose autoinduction medium and co-expression of molecular chaperones GroEL/S. Strep-tag affinity purification enriched the enzyme 16-fold and yielded 15 mg pure enzyme from 100 mL of culture. Biochemical characterization revealed that PmAcy possesses beneficial traits for industrial application like high temperature and pH-stability. A heat activation of PmAcy was observed upon incubation at temperatures up to 80 °C. Hydrolytic activity of PmAcy was detected with several N-acyl-amino acids as substrates and exhibited the highest conversion rate of 773 U/mg with N-lauroyl-L-alanine at 75 °C. The enzyme preferred long-chain acyl-amino-acids and displayed hardly any activity with acetyl-amino acids. PmAcy was also capable of N-acyl-amino acid synthesis with good conversion rates. The best synthesis results were obtained with the cationic L-amino acids L-arginine and L-lysine as well as with L-leucine and L-phenylalanine. Exemplarily, L-phenylalanine was acylated with fatty acids of chain lengths from C8 to C18 with conversion rates of up to 75%. N-lauroyl-L-phenylalanine was purified by precipitation, and the structure of the reaction product was verified by LC–MS and NMR.
Many industrial processes are performed using harmful chemicals. The current technical synthesis of N -acyl-amino acids relies on acyl chlorides, which are typically obtained from phosgene chemistry. A greener alternative is the application of whole cells or enzymes to carry out synthesis in an environmentally friendly manner. Aminoacylases belong to the hydrolase family and the resolution of racemic mixtures of N -acetyl-amino acids is a well-known industrial process. Several new enzymes accepting long-chain fatty acids as substrates were discovered in recent years. This article reviews the synthetic potential of aminoacylases to produce biobased N -acyl-amino acid surfactants. The focus lays on a survey of the different types of aminoacylases available for synthesis and their reaction products. The enzymes are categorized according to their protein family classification and their biochemical characteristics including substrate spectra, reaction optima and process stability, both in hydrolysis and under process conditions suitable for synthesis. Finally, the benefits and future challenges of enzymatic N -acyl-amino acid synthesis with aminoacylases will be discussed.
A novel and innovative method was developed to fabricate defect-free composite hollow fiber (HF) membranes using drop-casting under continuous flow. The synthesized Pebax-1657—based membranes were examined for gas separation processes, focusing on the separation of CO2 from CH4 and CO gases. The separation performance of the membranes was rigorously assessed under realistic binary gas mixture conditions to evaluate their selectivity and performance. The effect of pressure on separation performance was systematically investigated, with transmembrane pressures up to 10 bar being applied at a temperature of 298 K. Remarkable CO2/CH4 selectivities of up to 110 and CO2/CO selectivities of up to 48 were achieved, demonstrating the robustness and effectiveness of these composite HF membranes, suggesting their suitability for high-performance gas separation processes under varying operational conditions. Overall, this study introduces a novel approach for scaling up the fabrication of HF membranes and provides valuable insights into their application in CO2 separation technologies, offering the potential for advancements in areas such as natural gas processing and carbon capture from CO-containing streams.
The serine/threonine kinase CK2 (formerly known as casein kinase II) plays a crucial role in various CNS disorders and is highly expressed in various types of cancer. Therefore, inhibiting this key kinase could be promising for the treatment of these diseases. The CK2 holoenzyme is formed by the recruitment of two catalytically active CK2α and/or CK2α′ subunits by a regulatory CK2β dimer. Starting with the lead furocarbazole W16 (4) inhibiting the CK2α/CK2β interaction, analogous pyrrolocarbazoles were prepared and tested for their protein–protein interaction inhibition (PPII). The key step of the synthesis was a multicomponent Levy reaction of 2-(indolyl)acetate 6, benzaldehydes 7, and N-substituted maleimides 8. Targeted modifications were performed by the saponification of the tetracyclic ester 9a, followed by the coupling of the resulting acid 10 with diverse amines. The replacement of the O-atom of the lead furocarbazole 4 by an N-atom in pyrrolocarbazoles retained or even increased the inhibition of the CK2α/CK2β interaction. The large benzyloxazolidinyl moiety of 4 could be replaced by smaller N-substituents without the loss of the PPII. The introduction of larger substituents at the 2-position and/or at p-position of the phenyl moiety at the 10-position to increase the surface for the inhibition of the PPI did not enhance the inhibition of the CK2α/CK2β association. The strong inhibition of the CK2α/CK2β association by the histidine derivative (+)-20a (Ki = 6.1 µM) translated into a high inhibition of the kinase activity of the CK2 holoenzyme (CK2α2β2, IC50 = 2.5 µM). Thus, 20a represents a novel lead compound inhibiting CK2 via the inhibition of the association of the CK2α and Ck2β subunits.
Background: Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes.
Results: We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli . Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica , cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system.
Conclusion: Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated.
Onshore wind energy, the highest share of electricity production and the cheapest form of electricity in Germany has become an essential part of Germany’s aim to reach greenhouse gas neutrality in 2045. Still, its development faces social rejection due to perceived health problems that are as a result of wind turbines construction in close proximity to settlements. Forest, the second largest land use in Germany provides consistent wind resources for further expansion of wind energy generation but the social perception about wind energy in the forest is not great as forest is identified as the second largest natural carbon sink and provides some ecological benefits to humans and animals. This thesis sought to provide a quantitative comparison of the climate impact of wind turbines and forests.
Forest carbon stock of German forests was extracted from the German National Forest Inventory (NFI) database on the seven tree species and 2 species classification. The data available were the tree size and tree age. A multiple linear regression was used to estimate the influence of tree age and tree size on the carbon stock on a tree species. The model was performed using R language. The emission saving of Vestas V162-6.0 wind turbine was estimated and the results were compared to those of the results of the multiple linear regression.
It was determined that the emissions payback period of the wind turbine was seven (7) months, and the emissions avoided per year by the wind turbine was equivalent to the carbon stock of about 28 hectares of a matured forest. The research showed that both forest and wind energy are gains to climate change but in different ways and to be able to meet the climate goals, there should be a harmonious use of both resources.