Ashraf Abu-Seida

The driving patterns in developing countries, especially in metropolitan cities, are significantly different from those in developed countries or less-populated cities. However, most of the vehicles driven in these cities are tested using driving cycles that do not match those special driving characteristics, typically resulting in an underestimation or overestimation of the emission rates. In this study, a first driving cycle of passenger cars with gasoline engines is proposed for Greater Cairo, Egypt, based on a very large and diverse dataset of high-resolution onboard measurements, recorded using 87 cars driven in 10 distinctive areas in Greater Cairo. Two global driving cycles have been developed based on the commonly used K-means and the newly suggested K-medoids clustering techniques. The developed cycle based on the K-medoids algorithm, which was found more representative of the collected data, is a time series of speed, $\sim$1500 s, covering a distance of $\sim$5.4 km, with an average speed of 12.480 km/h, where 16.3% of the total duration spent in the idling mode. The superiority of the developed cycle over two commonly used cycles, namely the American transient FTP-75 cycle and the European modal ECE cycle, in terms of estimated fuel consumption and emission rates, is reported.

The nonlinear interaction between an elastic Euler beam and a tensionless soil foundation is studied. Exact analytical solutions of the challenging problem are rather complicated. The basic obstacle is imposing compatibility conditions at lift-off points. These points are determined as a part of the solution although being needed to get the solution itself. In the current work, solutions are derived using the approximate Rayleigh-Ritz method. The principal of vanishing variation of potential energy is adopted. The solution is approximated using a set of suitable trial functions. Lift-off points are identified through an iterative procedure and compatibility conditions are satisfied implicitly. Results are presented for various cases, including clamped support and free end condition. Various distributed loading conditions are analyzed. Exact solutions are revised briefly. Accurate high order approximate analytical solutions are obtained using MAXIMA symbolic manipulator. The convergence of approximate solutions towards the exact solutions is verified. For each case detailed results of deflection, bending moment and shear are presented.

The ever-growing interest in developing compact and more effective heat exchangers necessitates the investigation of combined passive solutions. Despite the diverse related literature, there are no studies on smooth conical tubes (convergent and divergent tubes) fitted with twisted tape inserts. This study analyzes and optimizes the absolute and relative thermal and hydraulic performances of tube heat exchangers, with and without twisted tape inserts, based on Nusselt number and friction factor, by adjusting the tube's diameter ratio and the operational Reynolds number. A consolidated framework of computational fluid dynamics simulations, data-driven multilayered perceptron-based modeling, and gradient-free genetic dual-objective optimization is employed. The results showed that conventional straight tubes are the most favorable in terms of hydraulic performance, with a maximum friction factor of only 0.042. Convergent tubes are the most effective in terms of thermal performance, with Nusselt numbers up to 475.9. Divergent tubes do not show potentials for heat transfer enhancement unless equipped with a tape insert. Twisted tapes effectively improve the thermal performances of all system configurations but also drastically increase the friction factor. Compared to a baseline design of an empty straight tube, the thermal performance can be improved by up to 74.8%. Almost all Pareto frontier solutions belonged to convergent tubes of different configurations. The selected moderate non-dominated solution (assuming equal importance of thermal and hydraulic performances) corresponds to a Nusselt number of 402.9 and a friction factor of 0.130 for a tape-fitted convergent tube with a diameter ratio of 0.445, operating at a Reynolds number of 39,854. In terms of relative performance, the moderate solution corresponds to a Nusselt number ratio of 1.535 and a friction factor ratio of 6.157 using a tape-fitted convergent tube with a diameter ratio of 0.385, operating at a Reynolds number of 31,254. Overall, convergent tubes are recommended as a simple way for boosting the heat transfer rate and the proposed models can be used as flexible tools for selecting the operating conditions based on the designer's preference.

Polymeric nanoparticles (NPs) are produced using bio-compatible and bio-degradable materials such as PLGA (Poly(lactic-co-glycolic acid)). This technology provides a valuable tool to deliver molecules to the subcellular level with a relatively low risk of cytotoxicity. However their use in the field of reproductive biotechnology is not yet scientifically substantiated. The aim of the present study was to test if PLGA NPs can be taken-up by cumulus-enclosed oocytes as a first step towards potential oocyte-targeted applications to enhance oocyte quality and fertility. We conducted a series of experiments using bovine in vitro oocyte maturation as a model to study FITC-conjugated PLGA internalization (using laser-scanning confocal microscopy) and the effect of some important physical (particle size) and chemical (conjugation with PEG) modifications. We show evidence that PLGA NPs can be taken-up by cumulus cells and to a less extent by the enclosed oocytes regardless of the NP size. The NP transfer to the oocyte appear to be transcellular (via cumulus cells and transzonal projections) and paracellular (via zona pellucida). The PLGA NPs were detected in the vicinity of the oocyte as quick as 2 h post-exposure in a protein-free medium and did not compromise cumulus cell viability nor subsequent early embryo development or embryo quality. These results suggest that PLGA NPs may have promising applications as carriers for drug or molecule delivery targeting cumulus cells and oocytes.

The current study aimed to load terconazole (TCZ), an antifungal agent with low permeability characteristics, into highly deformable bilosomes (HBs) for augmenting its topical delivery. HBs contain edge activator in addition to the constituents of traditional bilosomes (Span 60, cholesterol, and bile salts). More elasticity is provided to the membrane of vesicles by the existence of edge activator and is expected to increase the topical permeation of TCZ. HBs were formulated using ethanol injection technique based on 2⁴ complete factorial design to inspect the impact of various formulation variables (bile salt type and amount, edge activator type, and sonication time) on HBs characteristics (entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP)). The optimum formula (HB14) was decided based on Design-Expert^® software and was utilized for further explorations. HB14 exhibited EE% = 84.25 ± 0.49%, PS = 400.10 ± 1.69 nm, PDI = 0.23 ± 0.01, and ZP = - 56.20 ± 0.00 mV. HB14 showed spherical vesicles with higher deformability index (9.94 ± 1.91 g) compared to traditional bilosomal formula (3.49 ± 0.49 g). Furthermore, HB14 showed superior inhibition of Candida albicans growth relative to TCZ suspension using XTT (2,3-bis(2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay. Moreover, in vivo skin deposition studies revealed superior TCZ deposition inside the skin from HB14 compared to traditional bilosomal formula and TCZ suspension. Moreover, histopathological examination in rats assured the safety of HB14 for topical use. Concisely, the obtained outcomes confirmed the pronounced efficacy of HBs for topical delivery of TCZ.

Trials to improve oocyte developmental competence under metabolic stress by using antioxidants may start before or after oocyte maturation. In the present conceptual study, we aimed to identify the most efficient timing of antioxidant application in relation to a metabolic insult using a bovine invitro embryo production model. Pathophysiological concentrations of palmitic acid (PA) were used to induce metabolic stress during oocyte maturation or embryo development. Trolox (TR; antioxidant) treatment prior to, during or after the PA insult was tested to evaluate the protective, neutralising and rescuing capacity of TR respectively. Changes in embryo developmental competence, mitochondrial activity, reactive oxygen species (ROS) concentrations, blastocyst cell allocation and apoptosis and cell stress-related gene expression were monitored. The improvement in developmental capacity was most obvious when oocytes were preloaded with TR before the PA insult. This protective effect could be explained by the observed combination of increased mitochondrial activity with reduced ROS production. This resulted in blastocysts with normal cell counts and apoptosis, as well as increased nuclear factor erythroid 2-related factor 2 (NRF2) expression (a marker for redox regulatory processes) and normalised the expression of the mitochondrial transcription factor A (TFAM), a marker of mitochondrial biogenesis. These results indicate that 'pretreatment' of oocytes with antioxidants produces embryos that seem to be more resilient to a metabolic stress insult.