The early-stage detection of α-synuclein (α-Syn), a hallmark biomarker of Parkinson's disease, is critical for timely diagnosis and therapeutic intervention. Herein, we report on a metal-enhanced fluorescence (MEF) immuno-biosensor constructed from a nanohybrid comprising glutathione (GSH)-capped CdSe/In2S3Se quantum dots (QDs), multishaped AuCu alloy nanoparticles (NPs) and reduced graphene oxide (rGO). The QDs-AuCu alloy NP-rGO nanohybrid was prepared via solution-phase assembly and anti- α-Syn antibodies (Ab) were immobilized via physical adsorption. Target α-syn interaction triggered fluorescence amplification, which was further supported by finite difference time domain (FDTD) simulations revealing localized electric field enhancement at the QDs-AuCu alloy NP-rGO interface. Notably, the QDs-AuCu alloy NP-rGO nanohybrid exhibited enhanced redox currents and reduced impedance, reflecting a synergistic contribution from the QDs, plasmon-active AuCu NPs and conductive rGO scaffold in facilitating efficient charge transport and interfacial electron transfer. Density functional theory (DFT) calculations revealed that introducing an In2S3Se shell around GSH-CdSe QDs led to a significant reduction in the HOMO-LUMO energy gap from 0.323 eV to 0.013 eV which was accompanied by a downward shift in the Fermi level from −1.99 eV to −4.10 eV. Post-self-consistent field (SCF) analysis of electron density and electrostatic potential (ESP) maps confirmed increased electron delocalization and a stronger internal dipole moment in CdSe/In2S3Se QDs compared to CdSe, as evidenced by compact density contours and intensified polarity in the ESP profiles. These changes were driven by increased orbital delocalization and stronger interfacial electronic coupling between core and shell atoms, thus confirming the role of the core/shell architecture in enhancing charge transfer and electronic conductivity. The QDs-AuCu alloy NP-rGO-Ab immunosensor achieved a wide dynamic detection range from 0.01 to 100 pg/mL, a limit of detection of 5.6 fg/mL and high recovery rates (94.0 - 99.4%) in spiked human serum. In addition, cytotoxicity assessment using HEK293T cells demonstrated that the QDs and QDs-AuCu alloy NP-rGO nanohybrid retained high cell viability across all tested concentrations whilst stability studies conducted in acidic buffers (pH 1 to pH 5) and in biologically relevant media, showed that the QDs remained structurally stable with no observable degradation or loss of optical performance.
This study focused on the development of insulating refractory bricks using quartzite, with a comprehensive analysis of their mechanical and thermal properties. The bricks were made from quartzite with 10% bentonite binder and water, added for mixing. Various tests were done (Xray Fluorescence, Thermogravimetric and Differential Thermal Analyses, apparent porosity, shrinkage, Loss on Ignition (LOI), compressive yield stress, and water absorption (WA)), following American Society for Testing and Materials' procedures. Microstructural analysis of the sample was observed using Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). These results provided valuable insights into the stability of the developed refractory bricks at high temperatures. Analysis of chemical composition from quartz bricks revealed significant SiO2 content (94.303%), emphasizing the material's superior refractory properties. LOI (0.5%) and shrinkage (0.2%) results indicated enhanced performance with good thermal stability and strength. Compressive stress yield indicated that the material exhibits good strength relative to the amount of binder used. WA results confirmed that the brick sample is suitable for high-temperature applications. SEM/EDS analysis unveiled intricate microstructural features, affirming the bonding agent's influence on the material's composition.
Institutional incentives are widely used to promote cooperation among autonomous, self-regarding agents, from human societies to multi-agent and AI systems. Existing work typically treats incentive design as a bi-objective problem: minimise institutional cost while achieving a high long-run frequency of cooperation. Whether such schemes also maximise social welfare–total population payoff net of institutional expenditure–has remained largely unexplored. We develop a welfare-centric framework for institutional incentives in finite, well-mixed populations playing a social dilemma (Donation Game and Public Goods Game), considering both rewards for cooperators and punishments for defectors. For each mechanism, we derive explicit expressions for expected social welfare and characterise how it depends on incentive efficiency and selection intensity. Analytically, we identify parameter regimes where social welfare has a single optimal incentive level and regimes with qualitative phase transitions, in which welfare becomes non-monotonic with multiple local optima. We prove that any welfare-maximising incentive is either zero or concentrated around a simple closed-form target, and we provide an efficient algorithm to compute these optima. Comparing rewards and punishment, we further derive closed-form conditions under which rewards outperform punishment in terms of social welfare for any given budget. Overall, our results reveal a systematic gap between incentives optimised for cost or cooperation frequency and those that maximise welfare.
Purpose The presence of lone founders, multiple family members (ownership dispersion) and few family members (ownership concentration), in family businesses, affects the stock price crash risk (SPCR) in different manners. The purpose of this study is to examine the distinct impact of lone founder ownership and family ownership concentration and dispersion on SPCR and moderating influence of financial literate female directors on this relationship. Design/methodology/approach This study used sample of 2,954 firm-year observations comprising non-financial firms listed on Pakistan Stock Exchange over the period 2012–2021. The authors used the ordinary least squares regression method to test the hypotheses and additionally used the Generalized Method of Moments estimation and two stage least squares analysis to check the robustness of the results. Findings The authors find that lone founder-owned firms are less prone to SPCR because of lower information asymmetry and a strong organizational identity. In contrast, weaker emotional ties and a preference for short-term gains in family-owned firms where ownership is dispersed across multiple family members lead to a higher crash risk. Moreover, the presence of female directors with a financial background moderates these relationships and further reduces the likelihood of crash risk. Originality/value The results of this study provide novel evidence of distinct social behavior of lone founders and family owners and positive influence of financial literate female directors on SPCR in an emerging economy.
The global healthcare industry is grappling with a severe nursing shortage, with estimates projecting a deficit of 4.8 million nurses and midwives by 2030, highlighting the critical need to understand and address factors influencing nurse turnover intentions. This study investigates the relationships between value congruence, perceived fairness, emotional exhaustion, and turnover intentions among nurses in Ghana. It also seeks to examine the mediating role of emotional exhaustion and the moderating impact of perceived organizational trust. A quantitative study was conducted to gather data from 528 registered nurses in the Northern regions of Ghana. Structural equation modeling and hierarchical regression analysis were employed to examine the proposed hypothesis. Results show that both value congruence and perceived fairness negatively influence emotional exhaustion and turnover intentions. Emotional exhaustion was discovered to mediate the relationships between value congruence and turnover intentions, as well as between perceived fairness and turnover intentions. Additionally, perceived organizational trust moderates the nexus between emotional exhaustion and turnover intentions. These findings advance our knowledge of nurse retention in developing countries and have important implications for healthcare management. The study suggests that healthcare organizations should prioritize aligning organizational values with those of nursing staff, enhancing perceptions of fairness, addressing emotional exhaustion, and building trust to reduce turnover intentions. This research provides valuable insights for developing comprehensive strategies to improve nurse retention, ultimately enhancing the quality of patient care.
