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Dyonic Taub-NUT-AdS spaces: Phase structures of all horizon geometries
Get PDFWe study phase structures of Lorentzian Dyonic Taub-NUT-AdS spacetimes for different horizon geometries, which could be spherical, flat, or hyperbolic. We check the consistency of our extended thermodynamics approach through satisfying the first law, the Gibbs-Duhem relation, and the generalized Smarr\u27s relation. Although we study the phase structure for the three cases, we give special attention to the flat and hyperbolic cases since they are known to show no phase transitions and were not studied before. Working in a mixed ensemble, we found that the behaviors of the flat and hyperbolic cases are different from those of a charged black hole. In the latter case, a continuous phase transition occurs at high temperatures and pressures, i.e., above the critical point, but in our cases it occurs at low temperatures and pressures, i.e., below the critical point! Generically, the spherical case is characterized by two critical points with continuous phase transition between them
Optimized poly(methyl methacrylate)/mixed-phase silver vanadate nanocomposites with tuned optical properties and hydrophobicity
No full textThe fast advancements in technology have generated significant interest in optoelectronic materials. Nevertheless, the difficulty of creating affordable materials with exceptional optical characteristics is an ongoing challenge. Therefore, the objective of this work was to tune the optical properties of poly(methyl methacrylate) (PMMA) by embedding silver vanadate (SV) in the polymer matrix. Moreover, the wettability test of the fabricated composite membranes showed a hydrophobic behavior, with the PMMA film containing 0.6 wt.% SV showed a contact angle of 86.75 ± 0.7°. Furthermore, SV showed high thermal stability with a maximum weight loss of 0.74% at 830°C, which is very high thermal stability at high temperatures. In addition, the 0.6 wt.% SV@PMMA film exhibited a maximum weight loss of 96.7% at 785°C. Moreover, the 0.6 wt.% SV@PMMA film showed the lowest indirect band gap energy (2.02 eV) compared to the other films and pure SV NPs. The findings demonstrate the potential of the synthesized films for optoelectronic applications
Mechanisms of Arachidonic Acid In Vitro Schistosomicidal Potential
No full textArachidonic acid (ARA) was shown to possess safe and effective schistosomicidal impact on larval and adult Schistosoma mansoni and Schistosoma hematobium in vitro and in vivo in laboratory rodents and in children residing in low and high endemicity regions. We herein examine mechanisms underlying ARA schistosomicidal potential over two experiments, using in each pool a minimum of 50 adult male, female, or mixed-sex freshly recovered, ex vivo S. mansoni. Worms incubated in fetal calf serum-free medium were exposed to 0 or 10 mM ARA for 1 h at 37 °C and immediately processed for preparation of surface membrane and whole worm body homogenate extracts. Mixed-sex worms were additionally used for evaluating the impact of ARA exposure on the visualization of outer membrane cholesterol, sphingomyelin (SM), and ceramide in immunofluorescence assays. Following assessment of protein content, extracts of intact and ARA-treated worms were examined and compared for SM content, neutral sphingomyelinase activity, reactive oxygen species levels, and caspase 3/7 activity. Arachidonic acid principally led to perturbation of the organization, integrity, and SM content of the outer membrane of male and female worms and additionally impacted female parasites via stimulating neutral sphingomyelinase activity and oxidative stress. Arachidonic powerful action on female worms combined with its previously documented ovocidal activities supports its use as safe and effective therapy against schistosomiasis, provided implementation of the sorely needed and long waited-for chemical synthesis
Impact behavior of a novel GaN/MoS2 composite photodiode based thin-film by RF-sputtering for fast response photodetection application
No full textIn this study, we present the manufacture and characterisation of a novel thin film photodiode based on a GaN/MoS2 composite. The purpose of this research is to explore the potential of this composite material for applications in fast response photodetection. The photodiodes were fabricated using physical vapor deposition technique. The investigation of the surface topology and structural characteristics of the nanostructured GaN/MoS2 thin films was conducted using scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction techniques. The electrical performance of the fabricated photodiodes was investigated by measuring their current–voltage (I–V) characteristics within a bias voltage range from − 2 to + 2 V. The external quantum efficiency of the photodiodes were measured to be up to 11.86% and 8.26% for the pn-photodiode and Schottky photodiode, respectively. On the other hand, the internal quantum efficiency of the fabricated photodiodes were measured to be up to 13.78% and 10.02% for the pn-photodiode and Schottky photodiode, respectively. Also, a response time of 800 µs and 18.23 ms for Schottky-photodiode and pn-photodiodes respectively. These results demonstrate the potential of GaN/MoS2 composite photodiodes for fast response photodetection applications
Fast response fabricated MoS2-photodiode based thin film
Get PDFIn this study, we present the fabrication and characterization of a thin film based on 1 T-MoS2 pn photodiode for the purpose of quick response photodetection application. The photodiode was fabricated using RF-sputtering process. The scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) techniques were employed to investigate the surface topology and structural characteristics of the nanostructured MoS2 thin film. The electrical properties of the photodiode that was produced were examined by conducting measurements of its current–voltage (I-V) characteristics across a range of bias voltages spanning from − 2 to + 2 V. The external quantum efficiency (EQE) of the pn photodiode that was produced was determined to be as high as 9.8%. Additionally, the internal quantum efficiency (IQE) was found to be as high as 10.5%. Furthermore, a time response of 1.748 ms was observed. The findings of this study illustrate the capability of MoS2 photodiodes in facilitating rapid response photodetection applications
Benzothiazinone analogs as Anti-Mycobacterium tuberculosis DprE1 irreversible inhibitors: Covalent docking, validation, and molecular dynamics simulations
Get PDFMycobacterium tuberculosis is a lethal human pathogen, with the key flavoenzyme for catalyzing bacterial cell-wall biosynthesis, decaprenylphosphoryl-D-ribose oxidase (DprE1), considered an Achilles heal for tuberculosis (TB) progression. Inhibition of DprE1 blocks cell wall biosynthesis and is a highly promising antitubercular target. Macozinone (PBTZ169, a benzothiazinone (BTZ) derivative) is an irreversible DprE1 inhibitor that has attracted considerable attention because it exhibits an additive activity when combined with other anti-TB drugs. Herein, 754 BTZ analogs were assembled in a virtual library and evaluated against the DprE1 target using a covalent docking approach. After validation of the employed covalent docking approach, BTZ analogs were screened. Analogs with a docking score less than –9.0 kcal/mol were advanced for molecular dynamics (MD) simulations, followed by binding energy evaluations utilizing the MM-GBSA approach. Three BTZ analogs–namely, Pub-Chem-155-924-621, PubChem-127-032-794, and PubChem-155-923-972– exhibited higher binding affinities against DprE1 compared to PBTZ169 with ΔGbinding values of – 77.2, –74.3, and –65.4 kcal/mol, versus –49.8 kcal/mol, respectively. Structural and energetical analyses were performed for the identified analogs against DprE1 throughout the 100 ns MD simulations, and the results demonstrated the great stability of the identified BTZ analogs. Physicochemical and ADMET characteristics indicated the oral bioavailability of the identified BTZ analogs. The obtained in-silico results provide promising anti-TB inhibitors that are worth being subjected to in-vitro and in-vivo investigations
Broadband PM6Y6 coreshell hybrid composites for photocurrent improvement and light trapping
Get PDFOur research focuses on enhancing the broadband absorption capability of organic solar cells (OSCs) by integrating plasmonic nanostructures made of Titanium nitride (TiN). Traditional OSCs face limitations in absorption efficiency due to their thickness, but incorporating plasmonic nanostructures can extend the path length of light within the active material, thereby improving optical efficiency. In our study, we explore the use of refractory plasmonics, a novel type of nanostructure, with TiN as an example of a refractory metal. TiN offers high-quality localized surface plasmon resonance in the visible spectrum and is cost-effective, readily available, and compatible with CMOS technology. We conducted detailed numerical simulations to optimize the design of nanostructured OSCs, considering various shapes and sizes of nanoparticles within the active layer (PM6Y6). Our investigation focused on different TiN plasmonic nanostructures such as nanospheres, nanocubes, and nanocylinders, analyzing their absorption spectra in a polymer environment. We assessed the impact of their incorporation on the absorbed power and short-circuit current (Jsc) of the organic solar cell
The relationship between board gender diversity and audit quality in Egypt
No full textPurpose: This paper aims to examine whether female representation on boards is significantly associated with audit fees paid by top Egyptian listed companies. Design/methodology/approach: The authors collect data on audit fees, board of directors\u27 characteristics and financial data for the top 100 companies listed on the Egyptian Exchange (EGX100) for a period of six years. The authors employ an ordinary least squares regression model to capture the relationship between board diversity (i.e. the proportion of female board directors) and the natural logarithm of audit fees while controlling for firm and industry fixed effects as well as other known firm characteristics. Findings: The authors find that audit fees are significantly associated with the proportion of females serving on firms\u27 boards of directors. The findings suggest a complementary relationship between females on boards, as a quality-enhancing board attribute; and audit fees, as a proxy for audit effort and audit quality. Research limitations/implications: Limitations of this study arise first from the relatively small sample size, and second from the fact that inferences may be specific to the Egyptian context and similar markets. Practical implications: The results have important implications for Egyptian policy makers and regulators in terms of board composition. Social implications: This study provides empirical evidence that further enforces the business case for women\u27s empowerment and the impact of this on the effectiveness of corporate governance. Originality/value: To the best of the authors’ knowledge, this is the first archival study to examine the association between female board representation and audit fees in Egypt
The Use of Economic Indicators as Early Signals of Stock Market Progress: Perspectives from Market Potential Index
Get PDFThe progress of financial markets depends on the way world investors foresee the market potential of the country of choice. Countries that are associated with favorable economic incentives are able to motivate investments in their respective stock markets. The objective of this paper is to examine the role of the many economic components which constitute the Market Potential Index in enhancing stock market progress. The methodology goes through testing and estimation. The tests include linearity versus nonlinearity (RESET), normality, and cointegration. The estimation includes cointegration regression and discriminant analysis to distinguish between high and low stock market progress. This study examines unbalanced panel data that covers the years 1996–2022 for 54 countries where a stock market exists. The results show the following: (a) increases in people’s expenditure result in decreases in consumption of investment in financial securities; (b) the investments in infrastructure technology is positively associated with stock market progress; (c) the positive effect of economic freedom indicates that further adaptive trading regulations are beneficial to stock market progress; (d) increases in imports consume large proportions of people’s income, coming at the expense of investment in financial securities; (e) stock markets that are associated with high country risk are characterized by a positive risk–return tradeoff, i.e., a high risk premium; (f) the stock markets listed in the MPI can reach high progress by improving three indicators, namely commercial infrastructure, market receptivity, and country risk. This paper offers a thorough and unique examination of the institutional arrangements and stock market progress. The paper offers a guide to policy makers about how economic institutional arrangements can be promoted in order to reach high stock market progress
Bridging the credit gap: The influence of regional bank structure on the expansion of peer-to-peer lending
No full textThis paper investigates the extent to which the regional credit market structures, characterized by the presence and lending capacity of traditional banks, shape the growth of online lending marketplaces using peer-to-peer (P2P) lending data. Using an instrumental variables (IV) approach, our study suggests that areas underserved by traditional banks witness more significant growth in P2P lending. This impact is more pronounced in regions with a lower presence of small bank outreach. Furthermore, we find that an increase in P2P lending is associated with a reduced risk of borrower default. Our findings also show that the expansion of online lending marketplaces positively impacts borrowers’ financial well-being by improving their credit scores