13780 research outputs found
Sort by
Compositionally Tunable Mn-V-Fe Phosphoselenide Nanorods with Minimal Ion-Diffusion Barrier as High Energy Density Battery Electrode Materials
No full textThe design and synthesis of novel heterostructured electrode materials are crucial to enable the fabrication of efficient supercapacitor devices. In this regard, transition metal phosphochalcogenides (S, Se) are promising candidates owing to their exotic electronic properties. Herein, a facile two-step hydrothermal protocol was used to synthesize binary and ternary metal phospho-selenide electrodes (Mn-Fe-P-Se, V-Fe-P-Se, Mn-V-P-Se, and Mn-Fe-V-P-Se). The chemical composition, morphology, and structure of the as-fabricated materials were fully investigated. The three-electrode electrochemical evaluation at 1.0 A g-1 demonstrated that the ternary metal electrode (MFVP-Se) exhibits a high capacity of 1968.63 C g-1. To assess the practical value of the rationally designed Mn-Fe-V-P-Se electrode material, Mn-Fe-V-P-Se was used as a positive electrode coupled with activated carbon (AC) as a negative electrode to assemble a hybrid supercapacitor device. This Mn-Fe-V-P-Se//AC device delivers a power density of 1999.96 W kg-1 with a high energy density of 149.88 Wh kg-1 coupled with no capacity loss after 5000 charging/discharging cycles. Additionally, density functional theory calculations revealed that our electrode exhibits suitable adsorption energy for OH- ions with a minimal diffusion barrier for ions
Mangroves in Egypt and the Middle East: current status, threats, and opportunities
No full textMangrove forests are among the Nature Based Solutions (NBS) that help in mitigating climate change effects as they sequester carbon dioxide gas four times greater than normal forests. They stabilize coastlines, reduce coastal flooding, and provide nurseries to wildlife. Only two mangrove species exist in the Middle East: Avicennia marina and Rhizophora mucronata, due to their high tolerance to the region’s harsh and dry environmental conditions. This paper presents a comprehensive review on the current mangrove status in these countries, threats facing them, and rehabilitation initiatives taken to increase mangrove plantations in the Middle East. The review showed that Middle Eastern mangroves are dwarves, grow in dispatched form, have limited access to freshwater inflow, and are dominated by Avicennia marina specie. The largest and smallest mangrove cover were 20,400 ha and 80 ha found in Saudi Arabia and Bahrain respectively. Uncontrolled camel grazing, oil spills, habitat destruction, irresponsible tourism, and solid waste accumulation are from the major threats facing mangrove ecosystems. Climate change impacts through increased seawater salinity and temperature, microplastics, and heavy metals introduction to seawater threaten mangroves health. Various mangrove rehabilitation initiatives have taken place in Oman, Bahrain, UAE, Saudi Arabia, and Egypt as they have planted 1.5 million, 140 thousand, 1 million, 4.3 million, and 0.3 million mangrove trees respectively. This research presents some regulatory framework and policies needed for mangrove plantations rehabilitation for the mitigation of Green House Gases (GHG) and improve the livelihood of the indigenous people living along the coastal areas of the world
Repurposing of drug candidates against Epstein–Barr virus: Virtual screening, docking computations, molecular dynamics, and quantum mechanical study
No full textEpstein–Barr virus (EBV) was the first tumor virus identified in humans, and it is mostly linked to lymphomas and cancers of epithelial cells. Nevertheless, there is no FDA-licensed drug feasible for this ubiquitous EBV viral contagion. EBNA1 (Epstein-Barr nuclear antigen 1) plays several roles in the replication and transcriptional of latent gene expression of the EBV, making it an attractive druggable target for the treatment of EBV-related malignancies. The present study targets EBV viral reactivation and upkeep by inhibiting EBNA1 utilizing a drug-repurposing strategy. To hunt novel EBNA1 inhibitors, a SuperDRUG2 database (\u3e 4,600 pharmaceutical ingredients) was virtually screened utilizing docking computations. In accordance with the estimated docking scores, the most promising drug candidates then underwent MDS (molecular dynamics simulations). Besides, the MM-GBSA approach was applied to estimate the binding affinities between the identified drug candidates and EBNA1. On the basis of MM-GBSA//200 ns MDS, bezitramide (SD000308), glyburide (SD001170), glisentide (SD001159), and glimepiride (SD001156) unveiled greater binding affinities towards EBNA1 compared to KWG, a reference inhibitor, with ΔGbinding values of −44.3, −44.0, −41.7, −40.2, and −32.4 kcal/mol, respectively. Per-residue decomposition analysis demonstrated that LYS477, ASN519, and LYS586 significantly interacted with the identified drug candidates within the EBNA1 binding pocket. Post-dynamic analyses also demonstrated high constancy of the identified drug candidates in complex with EBNA1 throughout 200 ns MDS. Ultimately, electrostatic potential and frontier molecular orbitals analyses were performed to estimate the chemical reactivity of the identified EBNA1 inhibitors. Considering the current outcomes, this study would be an adequate linchpin for forthcoming research associated with the inhibition of EBNA1; however, experimental assays are required to inspect the efficiency of these candidates
On the Versatility of the sp-, sp\u3csup\u3e2\u3c/sup\u3e-, and sp\u3csup\u3e3\u3c/sup\u3e-Hybridized Chalcogen-Bearing Molecules To Engage in Type I Chalcogen···Chalcogen Interactions: A Quantum Mechanical Investigation of Like···Like and Unlike Complexes
No full textThe predilection of sp-, sp2-, and sp3-hybridized chalcogen-bearing molecules to engage in type I chalcogen···chalcogen interactions was comparatively unveiled in like···like/unlike CY···YC, YCY···YCY, and F2Y···YF2 (where Y = O, S, and Se) complexes, respectively. Upon the optimized monomers, a potential energy surface (PES) scan was conducted to pinpoint the most favorable complexes. The energetic findings unveiled the ability of the investigated systems to engage in the interactions under study with binding energy values ranging from −0.36 to −2.33 kcal/mol. Notably, binding energies were disclosed to align in the posterior sequence; sp2- (i.e., YCY···YCY) \u3e sp- (i.e., CY···YC) \u3e sp3- (i.e., F2Y···YF2) hybridized complexes, except the like···like oxygen-bearing complexes. Instead, the highest negative binding energy values were detected for the OCO···OCO followed by those of the F2O···OF2 and CO···OC complexes. Furthermore, the like···like selenium-bearing complexes demonstrated the most considerable binding energies compared to the other investigated complexes. Remarkably, the quantum theory of atoms in molecules and noncovalent interaction index analyses revealed the highly directional and closed-shell nature of the investigated chalcogen···chalcogen interactions. Symmetry adapted-perturbation theory findings outlined the dispersion forces as the commanding forces for all the studied complexes. These observations will provide convincing justifications for the nature of chalcogens within type I chalcogen···chalcogen interactions, leading to increased progress in various domains regarding drug design and materials science
RuC nanosheet as a promising biosensing material for detecting the aromatic amino acids: a DFT study
No full textDensity functional theory (DFT) calculations were performed to examine the potential of the RuC nanosheet as a biosensor towards the aromatic amino acids (AAA; tryptophan (TRP), histidine (HIS), tyrosine (TYR), and phenylalanine (PHE)). The AAA molecules were placed vertically and horizontally with respect to the RuC surface and then subjected to geometrical relaxation. According to the geometry relaxation results, it was found that all AAA molecules preferred to be adsorbed on the RuC surface in a horizontal configuration rather than a vertical one, except the HIS molecule, which desired to be vertically adsorbed on the RuC nanosheet. From the energy manifestations, the adsorption process within the TRP⋯RuC complexes had the greatest desired negative adsorption energy (Eads), followed by HIS⋯, TYR⋯, and then PHE⋯RuC complexes (Eads = −40.22, −36.54, −23.95, and −16.62 kcal mol−1, respectively). As indicated by the FMO data, changes in the EHOMO, ELUMO, and Egap values of the RuC nanosheet following the adsorption process demonstrated the capacity of the RuC nanosheet to adsorb the AAA molecules. The outcomes of Bader charge transfer revealed that the RuC nanosheet had the ability to donate electrons to the AAA molecules during the adsorption process, supported by the positive Qt values. Consistent with the Eads conclusions, the TRP⋯RuC complexes had the largest Qt values, indicating the potential affinity of the RuC nanosheet to adsorb the TRP molecule. Following the adsorption of AAA molecules on the RuC nanosheet, new peaks and bands were discovered based on the DOS and the band structure plots, respectively, revealing the validity of the adsorption process. Additionally, the current adsorption findings on the RuC nanosheet were compared to those on the graphene (GN) nanosheet. The outcomes of the comparison demonstrated the outperformance of the RuC nanosheet over the GN nanosheet in adsorbing the AAA molecules. These outcomes provide a solid foundation for further research on the RuC nanosheets to detect small biomolecules
A new non-parametric estimation of the expected shortfall for dependent financial losses
No full textIn this paper, we address the problem of kernel estimation of the Expected Shortfall (ES) risk measure for financial losses that satisfy the α-mixing conditions. First, we introduce a new non-parametric estimator for the ES measure using a kernel estimation. Given that the ES measure is the sum of the Value-at-Risk and the mean-excess function, we provide an estimation of the ES as a sum of the estimators of these two components. Our new estimator has a closed-form expression that depends on the choice of the kernel smoothing function, and we derive these expressions in the case of Gaussian, Uniform, and Epanechnikov kernel functions. We study the asymptotic properties of this new estimator and compare it to the Scaillet estimator. Capitalizing on the properties of these two estimators, we combine them to create a new estimator for the ES which reduces the bias and lowers the mean square error. The combined estimator shows better stability with respect to the choice of the kernel smoothing parameter. Our findings are illustrated through some numerical examples that help us to assess the small sample properties of the different estimators considered in this paper
The Political Economy of Egyptian Migration to Europe in the 2020s
No full textThe EU and Egypt share a neoclassical conceptual understanding of Egyptian migration, grafted by the network theory, in its criminal shape. In accordance with the neoclassical explanations and for political considerations, since the 1970s, Egypt sought to promote labour migration so as to release pressures on its labour market and to bring it valued remittances. Yet, Egypt, realizing the heightened EU concern with irregular migration chose to cooperate in defusing it. It resorted to issue-linking, giving up on legal migration opportunities to Europe, in return for benefits for its migration governance, locally-focused development and, importantly, for higher political motives. Operationalizing an agreed policy framework, the actions funded by the EU and its member states and those unilaterally taken by Egypt generated outcomes to the satisfaction of the EU. They also produced the benefits sought by Egypt. This looks like a perfect exchange based on the interdependence of the two parties. Yet, irregular migration persists and Egyptian HSM increases. Clinging to its conceptual foundation only, this framework ignores the arguments advanced by approaches such as the dual labour market and world system theories. The EU-Egypt conceptual framework should integrate these theories and devise corresponding policies and actions
The Effect of Water Scarcity on Gender Dynamics in Egypt
Get PDFThis article investigates the complex relationship between Egypt\u27s agriculture, water scarcity, and gender dynamics. It highlights the challenges facing the agricultural sector due to water shortages in a country highly dependent on the Nile River for food security and agricultural development. Women, who have been traditionally integral to agriculture, have to deal with multiple challenges posed by water scarcity. For men, their roles are changing, and with that, the power dynamics and social norms. This article attempts to reveal opportunities for gender equality and sustainable use of water resources through the examination differences in experiences between men and women in agricultural water management. It uses an approach that relies on secondary thematic analysis sources, such as published works, research articles, and case studies. The challenges faced by women are further highlighted, with certain strategies that can be utilized toward the incorporation of gender sensitive water resource management into agricultural planning. A conclusion providing some practical recommendations and emphasis on vertical gardens as a sustainable solution will then be explored. Comprehending the relationship among agriculture, water shortage, and gender dynamics contributes to bigger attempts at imposing equality between genders and sustainable water management practices in Egypt
‘The Place in Which My Heart Dwells’: Propaganda in Ancient Egypt
No full textThis Audio Feature was produced for the Audio Production course, taught by Professor Kim Fox. It discusses how propaganda was used before mass media, specifically in Ancient Egypt