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Discharge optimization in shell-and-tube latent heat storage systems using response surface methodology
Get PDFThis study addresses the critical challenge of optimizing heat recovery rates (HRR) in phase change material (PCM)-based thermal storage systems, which are essential for improving energy efficiency and supporting sustainable energy solutions. Efficient thermal storage is pivotal for managing fluctuating energy demands and integrating renewable energy sources. To optimize the design parameters, five critical variables—vertical and horizontal tube spacing, tube diameter, tube height from the bottom, and aspect ratio—are systematically evaluated using the Taguchi method. By considering four levels for each variable, the required experimental configurations are reduced from 45 to 16 trials, streamlining the optimization process. Response Surface Methodology (RSM) is applied to model the heat recovery behavior, achieving high predictive accuracy (R² = 0.9). The study finds that vertical tube spacing and horizontal spacing are the dominant factors, contributing to ∼57.6 % and ∼12.6 % of the total HRR variance, respectively, with the optimized design resulting in a 24.4 % improvement in HRR
Reinforcement Q-Learning-Based Adaptive Encryption Model for Cyberthreat Mitigation in Wireless Sensor Networks
Get PDFThe increasing prevalence of cyber threats in wireless sensor networks (WSNs) necessitates adaptive and efficient security mechanisms to ensure robust data transmission while addressing resource constraints. This paper proposes a reinforcement learning-based adaptive encryption framework that dynamically scales encryption levels based on real-time network conditions and threat classification. The proposed model leverages a deep learning-based anomaly detection system to classify network states into low, moderate, or high threat levels, which guides encryption policy selection. The framework integrates dynamic Q-learning for optimizing energy efficiency in low-threat conditions and double Q-learning for robust security adaptation in high-threat environments. A Hybrid Policy Derivation Algorithm is introduced to balance encryption complexity and computational overhead by dynamically switching between these learning models. The proposed system is formulated as a Markov Decision Process (MDP), where encryption level selection is driven by a reward function that optimizes the trade-off between energy efficiency and security robustness. The adaptive learning strategy employs an -greedy exploration-exploitation mechanism with an exponential decay rate to enhance convergence in dynamic WSN environments. The model also incorporates a dynamic hyperparameter tuning mechanism that optimally adjusts learning rates and exploration parameters based on real-time network feedback. Experimental evaluations conducted in a simulated WSN environment demonstrate the effectiveness of the proposed framework, achieving a 30.5% reduction in energy consumption, a 92.5% packet delivery ratio (PDR), and a 94% mitigation efficiency against multiple cyberattack scenarios, including DDoS, black-hole, and data injection attacks. Additionally, the framework reduces latency by 37% compared to conventional encryption techniques, ensuring minimal communication delays. These results highlight the scalability and adaptability of reinforcement learning-driven adaptive encryption in resource-constrained networks, paving the way for real-world deployment in next-generation IoT and WSN applications
The effectiveness of game-based literacy app learning in preschool children from diverse backgrounds
Get PDFFamily background factors like socio-economic status (SES) and migration background, along with child characteristics such as gender and intelligence, significantly influence early childhood competencies. Children from families with low SES and/or migration background often show weaker literacy outcomes than their peers. Game-based learning via apps can support children's competency development, but its effects may depend on children's app usage and how it interacts with child and family characteristics. We examined the effects of specifically developed literacy apps with N = 500 preschoolers (MAge = 60.96 months). The intervention was successful: Children who used our literacy apps obtained greater literacy competencies compared to a control group, even after accounting for family and child characteristics. Longer app usage time was associated with literacy gains, independent of SES and migration background, with a U-shaped relation, but only among girls. Consequently, game-based learning via apps can be successful; however, individual differences should be considered
The flavonoid hyperoside attenuates the toxic effect of cisplatin on the human ovarian granulosa cells: in vitro model study
No full textPremature ovarian insufficiency/failure is a well-known long-term risk of chemotherapy including CDDP in women. Granulosa cells (GCs) are an essential ovarian cell type that promotes oocyte growth and is crucial for ovarian reproductive function. Hyperoside (HYP) is a flavonoid known for its beneficial pharmacological properties, including anti-inflammatory and antiapoptotic effects. Hence the current work aimed to evaluate the potential cytoprotective impact of HYP on CDDP-induced cytotoxicity in a human ovarian GCs cell line model via a wide range of assays including MTT, hormones secretion, ATP and mitochondrial membrane potential, reactive oxygen species, lipid peroxidation as well as antioxidant enzymes, Caspases, and Akt kinase activities. Forty-eight-hour exposure to 5–10µM CDDP resulted in reduction of GCs viability in a dose-dependent manner. HYP (40 µM) was found to ameliorate this CDDP -induced effect on GCs viability. CDDP in a concentration-dependent way, dramatically reduced cellular ATP, mitochondrial activities, cellular progesterone, and estradiol secretion. It also increased oxidative stress markers, cytochrome c levels, caspase −3.-8.-9, and Bax/Bcl2 ratio with decreased Akt kinase activity and its coding genes expression. These cytotoxic effects of CDDP on the treated GCs, were mitigated to varying degrees by HYP (40 µM). In conclusion, CDDP-induced cytotoxic effects on GCs seem to be the possible underlying cellular and molecular mechanisms of CDDP-induced ovarian insufficiency/failure. The study also demonstrated the therapeutic potential of HYP in mitigating CDDP-induced ovarian injury. Further studies are warranted to investigate the potential benefit of HYP as an adjuvant to CDDP treatment protocols to avoid adverse ovarian effects
On p-refined Friedberg–Jacquet integrals and the classical symplectic locus in the GL 2n eigenvariety
Get PDFFriedberg–Jacquet proved that if π is a cuspidal automorphic representation of GL2n(A), then π is a functorial transfer from GSpin2n+1 if and only if a global zeta integral ZH over H=GLn×GLn is non-vanishing on π. We conjecture a p-refined analogue: that any P-parahoric p-refinement π~P is a functorial transfer from GSpin2n+1 if and only if a P-twisted version of ZH is non-vanishing on the π~P-eigenspace in π. This twisted ZH appears in all constructions of p-adic L-functions via Shalika models. We connect our conjecture to the study of classical symplectic families in the GL2n eigenvariety, and—by proving upper bounds on the dimensions of such families—obtain various results towards the conjecture
Identification of an a-factor-like pheromone secreted by the heterothallic ascomycete Aspergillus fumigatus
Get PDFMembers of the fungal kingdom serve as models for numerous cellular processes, among them sexuality. In heterothallic ascomycetes, mating-type systems ensure that only compatible isolates fuse to enter the sexual phase. This includes reciprocal secretion and recognition of pheromones, commonly termed a-factor and a-factor, which are processed from peptide precursors. Identification of fungal mating pheromones and their cognate receptors has been achieved by homology searches; however, this approach had failed to detect a-factor-like pheromones from Eurotiomycetes, a fungal group including medically and economically important species. Sexuality of the opportunistic pathogen Aspergillus fumigatus is genetically determined by a bipolar mating-type system encoding MAT1-1-1 and MAT1-2-1 regulators. By analyzing transcriptome data from strains overexpressing the corresponding MAT genes, we identified a candidate pheromone precursor gene B (ppgB) to encode the elusive Eurotiomycete a-factor pheromone. Its deduced peptide is 24 aa in length and features a canonical CaaX farnesylation motif. Further analyses provided supporting evidence that PpgB is a prototype for the a-factor-like pheromone of the aspergilli, including expression of ppgB in a MAT1-2-1-dependent manner, and that an A. fumigatus ppgBD deletion strain was unable to mate and form fruiting bodies with a compatible partner. Inspection of Aspergillus genomes from members of the section Fumigati revealed high conservation of PpgB sequence as well as of the a-factor-like PpgA, indicating that incompatibility factors other than solely pheromone discrimination are responsible for speciation. The identification of the A. fumigatus a-factor-like pheromone closes a substantial knowledge gap with respect to cellular recognition and sexual propagation of Eurotiomycete fungi
Adapting OptCouple to identify strategies with increased product yields in community cohorts of E. coli
Get PDFMicrobes as chemical factories provide an alternative sustainable approach for producing platform chemicals. Until recently, most efforts have involved engineering heterologous pathways into a single microbial chassis to maximise its production of a target chemical. More recently, cohorts of microbes have been used to engineer microbial communities to achieve higher yields than acheived in single chassis. In this paper, we present a computational approach to identify sets of metabolic modifications that create stable co-dependent communities of micro-organisms and improve the chemical yield of these communities. We demostrate our approach by designing communities which produce industrially relevant platform chemicals. We show that our approach is able to uncover metabolic engineering strategies for coupling these target chemicals to the growth of stable community cohorts
The Business of Poverty in Africa: Inside the Travel Philanthropy System
No full textThis timely and thought-provoking book critically explores key theories, concepts and contemporary issues associated with the travel philanthropy phenomenon and within the debates of sustainable development in Africa. Since the Band Aid era in 1984, and alongside the rise of the international aid and NGO sector, global travel and tourism has considerably expanded into the African continent and with it, face-to-face philanthropy too.By drawing on the authors’ extensive experience in the field of sustainable development and the African continent, and by using empirical evidence from case studies in Uganda, Ethiopia and Zimbabwe, a systems approach is employed to explain the complexity of travel philanthropy as a growing exchange economy within tourism in Africa and the importance of considering the influence of multi-stakeholder perspectives. Through an interdisciplinary lens framed by a critical realism philosophy, this book provides a thorough investigation and new understanding of travel philanthropy as a system, challenging myopic views of gift-giving and gift-receiving practices in Africa.Key system outputs reveal emerging moral dilemmas within gift-giving, leading to a call for adequate policy and practice interventions for the advancement of sustainable development. Incorporating observable and unobservable phenomena as matters of causality, a new conceptual model is presented, which redefines how impacts of travel philanthropy may be conceptualised and approached. By doing so the analysis offers significant insight into the real-world complexity of gift-giving and aid interventions through tourism, and how it differentiates from other forms of aid. The research presented in this book provides a solid basis to inform strategies for more effective and ethical pathways to gift-giving/receiving engagements, responsible tourism business management practices in Africa, and contributes to wider debates concerning international aid and donors’ intervention implications in African contexts.This book is a valuable resource for the tourism industry, policy makers, development professionals, students, researchers, academics in tourism, geography, business and management, economics, international development studies, anthropology, sociology, area studies, and applied ethics
Modular Combinatorial DNA Assembly of Group B Streptococcus Capsular Polysaccharide Biosynthesis Pathways to Expediate the Production of Novel Glycoconjugate Vaccines
Get PDFBackground/objectives: Streptococcus agalactiae (or Group B Streptococcus, GBS) is a major cause of neonatal meningitis globally. There are 10 serotypes of GBS, which are distinguished by their capsular polysaccharide (CPS) structure, with serotypes Ia, Ib, II, III, IV and V responsible for up to 99% of infections. Currently, there are no licensed vaccines against GBS. The most developed candidates are glycoconjugate vaccines, which can be highly effective but are also expensive to produce by existing approaches and unaffordable for many parts of the world. Biosynthesis of recombinant glycans and glycoconjugates in tractable strains of bacteria offers a low-cost alternative approach to current chemical conjugation methods. Methods: In this study, we apply combinatorial hierarchical DNA assembly to the heterologous biosynthesis of GBS III, IV and V CPSs in E. coli. Each gene was removed from its native regulation, paired with synthetic regulatory elements and rebuilt from the bottom up to generate libraries of reconstituted pathways. These pathways were screened for glycan biosynthesis using serotype-specific antisera. Results: We identified several configurations that successfully biosynthesised the GBS CPSs. Furthermore, we exploited the conserved nature of the GBS CPS biosynthesis loci and the flexibility of modular DNA assembly by constructing hybrid pathways from a minimal pool of glycosyltransferase genes. We show that transferase genes with homologous function can be used interchangeably between pathways, obviating the need to clone a complete locus for each new CPS assembly. Conclusions: In conclusion, we report the first demonstration of heterologous GBS CPS IV and V biosynthesis in E. coli, a key milestone towards the development of low-cost recombinant multivalent GBS glycoconjugate vaccines
Online peer support for people with dementia: a scoping review protocol
Get PDFObjective: The objective of this scoping review is to gain insights into the different online peer support opportunities available for people with dementia. Introduction: People with dementia use a variety of online platforms for peer support, such as social networking sites or videoconferencing platforms. Online peer support can offer a variety of benefits, such as overcoming geographical barriers and the opportunity to choose a platform and mode of communication that suits a person's needs and preferences. However, there is currently no synthesis of the different online peer support opportunities available to people with dementia. Inclusion criteria: Participants in this review will include people living with a self-reported diagnosis of any form of dementia. The concept is peer support through online platforms, while the context is online peer support that is accessible in English. Methods: The review will be conducted according to the JBI methodology for scoping reviews. A 3-step strategy will be used to search 4 data sources: (1) scholarly and gray literature databases, (2) Google search engine, (3) social media and websites of dementia organizations, and (4) consultations with people with dementia and professionals. The review will be managed in Covidence and Excel. The study selection and data extraction will be conducted by 2 independent reviewers and a third reviewer will be consulted if needed. For the data extraction a draft data extraction instrument will be used, following the recommendations of JBI. Data will be extracted on platform, online peer support, and study characteristics. The findings will be presented in tables and a narrative summary
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