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Purification of flavonoids from an aqueous cocoa (Theobroma cocoa L.) extract using macroporous adsorption resins
No full textCocoa is a rich source of health-promoting polyphenols such as flavanols. These compounds can be separated from other matrix constituents using various adsorbents or resins. Seven different macroporous resins (Amberlite® XAD-2, XAD-4, XAD-7, XAD-7HP, XAD-16, SepabeadsTM SP207, and Diaion® HP2-MG) were evaluated for their adsorption and desorption properties for the enrichment of flavonoids from an aqueous cocoa (Theobroma cacao L.) extract. The influence of adsorption and desorption temperatures and the concentration of the desorption solvent (a hydroalcoholic solution) were investigated by static adsorption and desorption methods. The results of the resin comparison showed that the adsorbent XAD-7HP had the best adsorption characteristics, with an adsorption capacity of 39.8 mg ECE/g. XAD-7HP was found to be the most suitable adsorbent, and 70% ethanol was the best desorbing solvent, based on static experiments. In addition, the optimal conditions for the adsorption of flavonoids were obtained at a temperature of 30 °C, where equilibrium was reached after 80 min. The static adsorption process was well-described by a pseudo-second-order kinetics model, while the adsorption isotherm data were fitted well by the Freundlich isotherm model. Further dynamic adsorption and desorption characteristics were evaluated on a packed glass column, and it was shown that XAD-7HP could enrich the flavanol content by 5.03-fold, with a dry matter content of 456.05 mg/mL (as estimated by the degree of DP1-DP7 procyanidin polymers using ultra-pressure liquid chromatography)
The value of leaders we trust and leaders who make us stronger : exploring the distinct contributions of different components of identity leadership to group member outcomes
No full textThis study investigates the critical role of social identity in leadership, specifically examining identity leadership (IL) and the unique contributions of its four subdimensions: identity prototypicality, identity advancement, identity entrepreneurship, and identity impresarioship. To date, research has largely focused on the global construct of identity leadership and shown that in organizational contexts, it is a predictor of a range of outcomes, including group members’ burnout and organizational citizenship. However, the distinct roles of the four subdimensions remain little understood. Extending earlier findings, we address this gap by testing the hypothesis that the four subdimensions are differentially implicated in two key mechanisms that underlie the relationship between IL and group outcomes: (a) trust in the leader and (b) team identification. The present study explores this proposition by using structural equation modeling with latent factors to test a mediation model in 2020–2021 data from the Global Identity Leadership Development project (GILD; N = 7,855). As hypothesized, we found that identity prototypicality and identity advancement predominantly predicted greater trust in the leader, whereas identity entrepreneurship primarily predicted greater team identification. Contrary to our hypothesis, identity impresarioship showed a negative relation with trust. In turn, both trust in the leader and team identification were positively associated with organizational citizenship behavior (OCB), and negatively with burnout. We conclude by reflecting on the implications of these findings for both the theory and practice of leadership
A domain-specific language for specifying requirement patterns for model-driven software development
No full textRequirement patterns have emerged in requirements engineering as a way to streamline requirements specification by promoting reuse. However, existing approaches in the literature have primarily focused on defining requirement patterns for reuse within textual requirement documents, overlooking software models. Meanwhile, other model-driven software development (MDSD) approaches that attempt to reuse software models as patterns for requirements specification are tied to specific modelling languages, limiting their applicability. In this paper, we introduce the LEMON specification language: a domain-specific language designed to specify and reuse requirement patterns for MDSD tools. The LEMON language supports the specification of patterns, templates, and the integration in any MDSD tools' metamodels, allowing requirements patterns customisation and their integration in MDSD environments. We present an Extended Backus-Naur Form (EBNF) of the LEMON language exemplified by means of an industry-inspired example. Moreover, we describe the implementation of an execution environment to show the integration of the LEMON language in an MDSD tool. We conclude with our vision and outline future steps for the evolution of the LEMON language to streamline requirements specification in MDSD tools using requirement pattern
Zwischen Beruf und Freizeit : Work-Life-Balance aus der Sicht von Achtklässler:innen.
No full textIn einer Gesellschaft, in der Stress, Zeitdruck und hohe Leistungsanforderungen zunehmend zum Alltag gehören, gewinnt das Thema Work-Life-Balance immer mehr an Bedeutung, insbesondere auch für junge Arbeitsnehmende. Vor diesem Hintergrund untersucht die vorliegende Arbeit, welche Rolle eine gute Balance zwischen Berufs- und Privatleben in den Berufsvorstellungen von Jugendlichen im Schulalter, konkret von Achtklässler:innen, hat. Zur Beantwortung dieser Frage wurde ein quantitativer Fragebogen in vier achten Klassen eingesetzt. Nebst Fragen mit vorgegebenen Antwortoptionen beinhaltete der Fragebogen am Ende eine offene Frage, um individuelle Einschätzungen zu erfassen. Die Auswertung zeigt, dass die grosse Mehrheit der befragten Achtklässler:innen ein klares Bedürfnis nach einer guten Work-Life-Balance äussert. Erholung, ausreichend Zeit für Familie, Freund:innen und Hobbys sowie feste Arbeitszeiten mit klarer Trennung von Berufs- und Privatleben stehen dabei im Vordergrund. Knapp etwas mehr als die Hälfte der Jugendlichen gibt an, sich in ihrer Freizeit durch schulische Verpflichtungen eingeschränkt zu fühlen. Dennoch zeigt sich, dass der Wunsch nach ausreichenden Erholungsphasen bei nahezu allen Teilnehmenden vorhanden ist, auch bei denjenigen, welche aktuell keine Einschränkungen in ihrer Freizeit verspüren. Trotz der Bedeutung der Work-Life-Balance hat das eigene Interesse am Beruf für die Achtklässler:innen die höchste Priorität. Gleichzeitig zeigen die Ergebnisse, dass die Bedeutung der Work-Life-Balance relativiert wird, wenn sie anderen Berufskriterien wie dem Lohn oder Karrieremöglichkeiten gegenübersteht. Dabei fällt auf, dass insbesondere männliche Jugendliche weniger bereit sind, zugunsten einer ausgewogenen Balance finanzielle Einbussen oder geringere Karrierechancen in Kauf zu nehmen. Die Untersuchung macht deutlich, dass die Vorstellung eines ausgeglichenen Berufs- und Privatlebens bei vielen Jugendlichen bereits vor dem Berufseintritt ein relevantes Thema ist. Für die schulische Berufsorientierung und die Berufsberatung bedeutet dies, dass je nach individuellen Bedürfnissen der Jugendlichen, neben Interessen und Fähigkeiten auch persönliche Werte im Hinblick auf die Work-Life-Balance verstärkt in den Fokus von Gesprächen rücken können
Computational analysis reveals temperature-induced stabilization of FAST-PETase
No full textMore than 10 % of global solid waste consists of poly(ethyleneterephthalate) (PET). Among other techniques, PET hydrolases (PETases) can be used to depolymerize this plastic. However, wildtype PETases exhibit poor specific activities and insufficient thermostability, limiting their use in depolymerization processes which require high temperatures. In 2022, machine learning-aided enzyme engineering of a PETase stemming from the bacterium Ideonella sakaiensis (IsPETase) resulted in a more functional, active, stable, and tolerant variant (FAST-PETase). To rationalize the molecular basis of FAST-PETase's improved thermal stability, we performed comparative Constraint Network Analysis (CNAnalysis) and Molecular Dynamics (MD) simulations of wildtype IsPETase (WT-PETase) and FAST-PETase at 30°C and 50°C identifying thermolabile sequence stretches in the wildtype enzyme. Further analysis of the backbone flexibility revealed that all mutations of FAST-PETase affected these critical regions. Counterintuitively, the in-silico analyses additionally highlighted that the flexibility of these regions decreased at 50°C in FAST-PETase, instead of exhibiting increased flexibility at higher temperature as would be expected from thermodynamic considerations. This effect was confirmed by physical energy calculations, which suggest that temperature-dependent conformational changes of FAST-PETase decrease the free energy of unfolding (ΔG(stability)) and rigidify the enzyme at elevated temperatures enhancing stability. Looking forward, these findings might help guide the rational engineering of protein thermostability and contribute to our understanding of the thermal adaptation of thermophilic enzymes
Innovative 3D printed semi-dry electrodes for EEG portable device
No full textEEG electrodes are essential for brain monitoring but face key limitations: wet types need messy gels, while dry types suffer from high impedance and motion artifacts. Our proposed 3D-printed semi-dry electrodes bridge this gap by releasing electrolytes through a degradable hydrogel activated by skin moisture. Encapsulating electrolyte droplets in a PDMS matrix enhances conductivity without external gels, enabling stable, comfortable, and user-friendly EEG interfaces.
3D-printed semi-dry electrodes with a degradable hydrogel enable moisture-activated electrolyte release, improving skin conductivity without external gels. This approach offers a customizable, cost-effective alternative to conventional EEG electrodes and lays the foundation for wearable neurotechnology. Future work should enhance hydrogel durability, optimize electrolyte compatibility, and improve signal quality
Book review : The Russia-Ukraine War and its implications on Central Asia edited by Assylzat Karabayeva and Ikboljon Qoraboyev, Lanham, Maryland, Lexington Press, 2024, pp. 238, $115.00 (hbk), ISBN 978-1666966473
No full textAssessing the environmental impact of IoT devices : hotspots and guidelines for a better understanding
No full textThis article presents a methodological framework for LCA studies of IoT solutions that captures the particularities of these devices and provides a complete picture of their environmental footprint. To this end, we start with a semi-structured literature review on LCA studies of IoT solutions, focusing on smart buildings and urban applications. Nine studies were analyzed and compared according to their system boundaries, environmental impact areas, and identified hotspots. Furthermore, we identify research gaps and challenges in conducting LCA studies and derive a framework for LCA studies of IoT solutions