Dielectric Function in Highly doped GaN Semiconductor

Inverse of Dielectric Function of highly doped  GaN has been calculated by using Lindhard formalism.  For simplicity collisional damping,  nonparabolicity and the coupling  between various  electrons and holes  were  neglected. The inverse of the dielectric function for both Fermi- Dirac and Maxwell Boltzman distribution showed antiscreening peak at small phonon wave vector. On the contrary, both Thomas Fermi and Debye inverse of dielectric function showed screening as expected at same phonon wave vector. There is a sharp growth in the antiscreening peak in the inverse of dielectric function at carrier temperature 77 K and 300K, accompanied with a singularity at carrier concentration greater than . Key words: dielectric function, GaN and screened optical phonon scattering rat

Seismic hazard studies in Egypt

Abstract The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal

Preparation of Ecofriendly Formulations Containing Biologically Active Monoterpenes with Their Fumigant and Residual Toxicities against Adults of Culex pipiens

Different mixtures of monoterpenes (ketone, alcohol, and alkene) were loaded on paper discs and wax and their knockdown activities were evaluated against Culex pipiens adults. Some individual monoterpenes were also evaluated by residual toxicity technique. Citronella oil as a reference was also loaded separately or in combination with monoterpenes on paper discs and wax. The ketone monoterpenes mixture (camphor, menthone, carvone, and fenchone) on paper discs was the most active (KT50 = 17.20 min) followed by ketone monoterpenes with citronella oil (KT50 = 20.79 min) and citronella oil alone (KT50 = 28.72 min). Wax formulations proved that the ketone and alcohol (geraniol, thymol, and menthol) monoterpenes gave the most activity as knockdown (KT50 = 31.79 and 43.39 min, resp.). Alcohol monoterpenes formulation recorded KT50 = 43.39 min. Residual activity of tested individual monoterpenes reported that the menthol was more toxic than camphor and camphene. Generally, this study suggests that the monoterpenes have the properties, which make them used as eco-friendly compounds in the control programs of Cx. pipiens adult. The use of paper discs is more applicable than wax in the adulticidal formulations

Formulation and Evaluation of Transdermal Gel Containing Tacrolimus-Loaded Spanlastics: In Vitro, Ex Vivo and In Vivo Studies

Our goal was to prepare Span 60-based elastic nanovesicles (spanlastics (SPLs)) of tacrolimus (TCR) using the adapted ethanol injection method, characterize them, and evaluate their ability to improve the transdermal permeation of the active substance. The impact of two different concentrations of penetration enhancers, namely, propylene glycol and oleic acid, on the entrapment efficiency, vesicle size, and zeta potential was assessed. Moreover, in vitro release through a semipermeable membrane and ex vivo penetration through hairless rat skin were performed. Morphological examination and pharmacokinetics were performed for one selected formulation (F3OA1). TCR-loaded SPLs were effectively formulated with two different concentrations of permeation enhancers, and the effect of these enhancers on their physicochemical properties differed in accordance with the concentration and kind of enhancer used. The results of in vitro release displayed a considerable (p < 0.05) enhancement compared to the suspension of the pure drug, and there was a correlation between the in vitro and ex vivo results. The selected TCR-loaded nanovesicles incorporated into a gel base showed appreciable advantages over the oral drug suspension and the TCR-loaded gel. Additionally, the pharmacokinetic parameters were significantly (p < 0.05) improved based on our findings. Moreover, the AUC0–7 ng·h/mL form F3 OA1 was 3.36-fold higher than that after the administration of the TCR oral suspension

Formulation and Evaluation of Transdermal Gel Containing Tacrolimus-Loaded Spanlastics: <i>In Vitro</i>, <i>Ex Vivo</i> and <i>In Vivo</i> Studies

Our goal was to prepare Span 60-based elastic nanovesicles (spanlastics (SPLs)) of tacrolimus (TCR) using the adapted ethanol injection method, characterize them, and evaluate their ability to improve the transdermal permeation of the active substance. The impact of two different concentrations of penetration enhancers, namely, propylene glycol and oleic acid, on the entrapment efficiency, vesicle size, and zeta potential was assessed. Moreover, in vitro release through a semipermeable membrane and ex vivo penetration through hairless rat skin were performed. Morphological examination and pharmacokinetics were performed for one selected formulation (F3OA1). TCR-loaded SPLs were effectively formulated with two different concentrations of permeation enhancers, and the effect of these enhancers on their physicochemical properties differed in accordance with the concentration and kind of enhancer used. The results of in vitro release displayed a considerable (p p 0–7 ng·h/mL form F3 OA1 was 3.36-fold higher than that after the administration of the TCR oral suspension

Novel Metoprolol-Loaded Chitosan-Coated Deformable Liposomes in Thermosensitive In Situ Gels for the Management of Glaucoma: A Repurposing Approach

Glaucoma is a long-term eye disease associated with high intraocular pressure (IOP), which seriously damages the eyes, causing blindness. For successful therapy, potent drugs and delivery systems are required. Metoprolol (MT) is believed to help reduce elevated IOP. The paradigm of ocular therapeutics may be changed by the integration of chitosan-coated liposomes (CLPs) with thermosensitive in situ gel (ISG). Therefore, MT-CLPs were developed and characterized and compared to uncoated ones (MT-LPs). Furthermore, MT-LP- and MT-CLP-loaded ISGs were prepared and characterized in in vitro, ex vivo, and in vivo studies. MT-LPs and MT-CLPs displayed spherical shapes with nanosize range, reasonable EE%, and significant bioadhesion. The zeta potential changed from negative to positive after CS coating. The extended in vitro drug release of MT-CLPs showed significant mucin mucoadhesion. The formed ISGs were homogeneous with a pH range of 7.34 to 7.08 and a rapid sol&ndash;gel transition at physiological temperature. MT-ISG1 (MT-LP) and MT-ISG2 (MT-CLPs-0.5) could increase ocular permeability by 2-fold and 4.4-fold compared to MT-ISG (pure MT). MT-ISG2 demonstrated significantly reduced IOP in rabbits without causing any irritation. In conclusion, MT-ISG2 markedly enhanced corneal permeability and reduced IOP. They would be promising carriers for MT for glaucoma management

An Effective Bi-Stage Method for Renewable Energy Sources Integration into Unbalanced Distribution Systems Considering Uncertainty

The output generations of renewable energy sources (RES) depend basically on climatic conditions, which are the main reason for their uncertain nature. As a result, the performance and security of distribution systems can be significantly worsened with high RES penetration. To address these issues, an analytical study was carried out by considering different penetration strategies for RES in the radial distribution system. Moreover, a bi-stage procedure was proposed for optimal planning of RES penetration. The first stage was concerned with calculating the optimal RES locations and sites. This stage aimed to minimize the voltage variations in the distribution system. In turn, the second stage was concerned with obtaining the optimal setting of the voltage control devices to improve the voltage profile. The multi-objective cat swarm optimization (MO-CSO) algorithm was proposed to solve the bi-stages optimization problems for enhancing the distribution system performance. Furthermore, the impact of the RES penetration level and their uncertainty on a distribution system voltage were studied. The proposed method was tested on the IEEE 34-bus unbalanced distribution test system, which was analyzed using backward/forward sweep power flow for unbalanced radial distribution systems. The proposed method provided satisfactory results for increasing the penetration level of RES in unbalanced distribution networks.Peer reviewe

Fabrication and Assessment of Orodispersible Tablets Loaded with Cubosomes for the Improved Anticancer Activity of Simvastatin against the MDA-MB-231 Breast Cancer Cell Line

Various factors limit the use of simvastatin as an anticancer drug. Therefore, this study aimed to analyse simvastatin (SIM)-loaded cubosome efficacy against breast cancer. SIM-loaded cubosomes were prepared using the emulsification method using different glyceryl monooleate, Pluronic F127 (PF-127), and polyvinyl alcohol (PVA) ratios. The best cubosomal formula was subjected to an in vitro cytotoxicity analysis using the human breast cancer cell line, MDA-MB-231 (MDA) (ATCC, HTB-26), and formulated as oral disintegrating tablets through direct compression. PF-127 and PVA positively affected drug loading, and the entrapment efficiency percentage of different SIM-cubosomal formulations ranged from 33.52% to 80.80%. Vesicle size ranged from 181.9 ± 0.50 to 316.6 ± 1.25 nm. PF-127 enhanced in vitro SIM release from cubosome formulations due to its solubilising action on SIM. The in vitro dissolution analysis indicated that SIM exhibited an initial dissolution of 10.4 ± 0.25% within the first 5 min, and 63.5 ± 0.29% of the loaded drug was released after 1 h. Moreover, cubosome formula F3 at 25 and 50 µg/mL doses significantly decreased MDA cell viability compared to the 12.5 µg/mL dose. The untreated SIM suspension and drug-free cubosomes at all doses had no significant influence on MDA cell viability compared to the control

Optimal Harmonic Mitigation in Distribution Systems with Inverter Based Distributed Generation

In recent years, with the widespread use of non-linear loads power electronic devices associated with the penetration of various renewable energy sources, the distribution system is highly affected by harmonic distortion caused by these sources. Moreover, the inverter-based distributed generation units (DGs) (e.g., photovoltaic (PV) and wind turbine) that are integrated into the distribution systems, are considered as significant harmonic sources of severe harmful effects on the system power quality. To solve these issues, this paper proposes a harmonic mitigation method for improving the power quality problems in distribution systems. Specifically, the proposed optimal planning of the single tuned harmonic filters (STFs) in the presence of inverter-based DGs is developed by the recent Water Cycle Algorithm (WCA). The objectives of this planning problem aim to minimize the total harmonic distortion (THD), power loss, filter investment cost, and improvement of voltage profile considering different constraints to meet the IEEE 519 standard. Further, the impact of the inverter-based DGs on the system harmonics is studied. Two cases are considered to find the effect of the DGs harmonic spectrum on the system distortion and filter planning. The proposed method is tested on the IEEE 69-bus distribution system. The effectiveness of the proposed planning model is demonstrated where significant reductions in the harmonic distortion are accomplished.Peer reviewe