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This paper examines the effect of geopolitical risk (GPR) on return and volatility dynamics in Middle East and North African (MENA) countries by using an ADCC-GARCH model and a spillover approach. Unlike previous studies, we include the GPR index to capture risk associated with wars, terrorist acts, and political tensions. Moreover, we test for both static and dynamic analysis using a rolling window. In brief, the findings highlight that GPR does not contribute to the return spillovers among MENA financial markets. However, the dynamic analysis provides evidence of the high level of responsiveness of the total spillover index to major political events (e.g., the Arab Spring uprising and political tension between Qatar and other Gulf Cooperation Council countries). More interestingly, Qatar, Kingdom of Saudi Arabia, and the United Arab Emirates are identified as the main transmitters of return spillovers to the rest of the MENA markets. Overall, our results are essential in understanding the impact of the GPR on return spillover among MENA countries, and are of particular importance to policymakers, market regulators, portfolio managers and investors.

Cholesterol oxidase is an alcohol oxidoreductase flavoprotein with wide biotechnological applications. The current work describes the isolation of a potential cholesterol oxidase producing streptomycete from Egyptian soil. The isolated strain produced cholesterol oxidase in submerged culture using a medium containing glucose, yeast extract, malt extract, and CaCO3 with the addition of cholesterol as an inducer. The isolated strain was identified as Streptomyces rochei NAM-19 based on 16S rRNA sequencing and phylogeny. Optimization of cholesterol oxidase production has been carried out using response surface methodology. The Plackett-Burman design method was used to evaluate the significant components of the production medium followed by Box-Behnken experimental design to locate the true optimal concentrations, which are significantly affecting enzyme production. Results showed that the predicted enzyme response could be closely correlated with the experimentally obtained production. Furthermore, the applied optimization strategy increased volumetric enzyme production by 2.55 times (65.1 U/mL) the initial production obtained before medium optimization (25.5 U/mL).

The incidence of the neurodegenerative disease “Alzheimer’s“(AD) is expected to reach up to 2.1 billion people aged 60 years old by 2050. Unsaturated fatty acids have been implicated in both protective and detrimental roles in AD. However, there is currently limited understanding of how varying levels of disease pathology in the brain influence the abundance of these fatty acid species. Within this framework, the present study aims to estimate the effect of fatty acids extracted from Cistanche phelypaea ( C. phelypaea ) on rats’ memory and behaviour. The fatty acids (FAs) extracted from the wild C. phelypaea were identified using GLC. Most of the FA were unsaturated. Oleic acid was the predominant fatty acid, followed by palmitic and linoleic acids. The study was conducted in two parallel arms, the first arm investigated the effect of C. phelypaea FAs on normal rats, and the second arm investigated its effect on Alzheimer’s disease rats and involved the following groups of rats: normal & untreated AD groups, reference group: donepezil (0.75 mg/kg), & C. phelypaea groups (100 and 200 mg/kg), all treatments were given concomitantly with AlCl 3 (172.5 mg/kg) to rats, by oral gavage for 3 successive weeks, followed by alternating Y-maze & grid floor activity cage tests, then the levels of acetylcholine esterase (AchE), β-amyloid and tau protein were measured in rats’ sera of rats. Finally, histopathological examination of rats’ brains was done. In both arms, C. phelypaea , the number of movements in the grid floor activity cage was compared to normal and untreated AD groups. In the second arm, both doses reduced the level of AchE; the high dose only reduced β-amyloid compared to untreated AD. The results were consistent with the histopathologic results. C. phelypaea FAs had promising effects on brain health.

Soft robots provide a pathway to accurately mimic biological creatures and be integrated into their environment with minimal invasion or disruption to their ecosystem. These robots made from soft deforming materials possess structural properties and behaviors similar to the bodies and organs of living creatures. However, they are difficult to develop in terms of integrated actuation and sensing, accurate modeling, and precise control. This article presents a soft-rigid hybrid robotic fish inspired by the Pangasius fish. The robot employs a flexible fin ray tail structure driven by a servo motor, to act as the soft body of the robot and provide the undulatory motion to the caudal fin of the fish. To address the modeling and control challenges, reinforcement learning (RL) is proposed as a model-free control strategy for the robot fish to swim and reach a specified target goal. By training and investigating the RL through experiments on real hardware, we illustrate the capability of the fish to learn and achieve the required task.

Background Pectinase enzymes present a high priced category of microbial enzymes with many potential applications in various food and oil industries and an estimated market share of $ 41.4 billion by 2020. Results The production medium was first optimized using a statistical optimization approach to increase pectinase production. A maximal enzyme concentration of 76.35 U/mL (a 2.8-fold increase compared with the initial medium) was produced in a medium composed of (g/L): pectin, 32.22; (NH 4 ) 2 SO 4 , 4.33; K 2 HPO 4 , 1.36; MgSO 4 .5H 2 O, 0.05; KCl, 0.05; and FeSO 4 .5H 2 O, 0.10. The cultivations were then carried out in a 16-L stirred tank bioreactor in both batch and fed-batch modes to improve enzyme production, which is an important step for bioprocess industrialization. Controlling the pH at 5.5 during cultivation yielded a pectinase production of 109.63 U/mL, which was about 10% higher than the uncontrolled pH culture. Furthermore, fed-batch cultivation using sucrose as a feeding substrate with a rate of 2 g/L/h increased the enzyme production up to 450 U/mL after 126 h. Conclusions Statistical medium optimization improved volumetric pectinase productivity by about 2.8 folds. Scaling-up the production process in 16-L semi-industrial stirred tank bioreactor under controlled pH further enhanced pectinase production by about 4-folds. Finally, bioreactor fed-batch cultivation using constant carbon source feeding increased maximal volumetric enzyme production by about 16.5-folds from the initial starting conditions.

This research presents a framework for visualizing bridge construction impact on work zone traffic using Bridge Information Modelling (BrIM) and Google Maps API. The framework consists of four modules. The first module contains the construction data of the bridge by reporting the construction's daily progress. The second module is designated to model traffic data of the work zone using Google Maps API, traffic Survey counting, and Google Earth Images. The third module performs a traffic simulation for the work zone, and calculating the user cost of different stages. The fourth module visualizes the bridge's construction using Bridge Information Modelling (BrIM) and virtual reality in the Twinmotion engine to demonstrate the construction stages and the corresponding traffic states. An actual case study of El-Nahas Bridge in Cairo city-Egypt is presented to demonstrate the main features of the developed framework and its practical aspects. The case study results reveal that the impact of the construction stages varies on work zone traffic throughout the project period. The impact greatly influences the traffic status at the beginning of the project associated with high user costs. Then, the impact declines in later stages depending on the type of construction activities in each stage.

Silver nanoparticles (AgNPs) are among the most widely synthesized and used nanoparticles (NPs). AgNPs have been traditionally synthesized from plant extracts, cobwebs, microorganisms, etc. However, their synthesis from wing extracts of common insect; Mang mao which is abundantly available in most of the Asian countries has not been explored yet. We report the synthesis of AgNPs from M . mao wings extract and its antioxidant and antimicrobial activity. The synthesized AgNPs were spherical, 40–60 nm in size and revealed strong absorption plasmon band around at 430 nm. Highly crystalline nature of these particles as determined by Energy-dispersive X-ray analysis and X-ray diffraction further confirmed the presence of AgNPs. Hydrodynamic size and zeta potential of AgNPs were observed to be 43.9 nm and -7.12 mV, respectively. Fourier-transform infrared spectroscopy analysis revealed the presence of characteristic amide proteins and aromatic functional groups. Thin-layer chromatography (TLC) and Gas chromatography-mass spectroscopy (GC-MS) analysis revealed the presence of fatty acids in the wings extract that may be responsible for biosynthesis and stabilization of AgNPs. Further, SDS-PAGE of the insect wing extract protein showed the molecular weight of 49 kDa. M . mao silver nanoparticles (MMAgNPs) exhibit strong antioxidant, broad-range antibacterial and antifungal activities, (66.8 to 87.0%), broad-range antibacterial and antifungal activities was found with maximum zone of inhibition against Staphylococcus aureus MTCC 96 (35±0.4 mm) and Fusarium oxysporum f . sp . ricini (86.6±0.4) which signifies their biomedical and agricultural potential.

Magnesium oxide nanoparticles (MgO NPs) represent an interesting inorganic material widely utilized across various fields including sensing, antimicrobial applications, optical coatings, water purification, fuel additives, absorbents, and catalysis, owing to their exceptional broad energy band gap, surface affinity, and strong chemical and thermal durability. In this investigation, MgO NPs were successfully synthesized through a green approach employing fruit extract from the gingerbread tree (Hyphaene thebaica). Analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed their agglomerated quasi-spherical shape with a size range of 20–60 nm. The X-ray diffraction (XRD) pattern exhibited prominent peaks at planes (200) and (220), indicating the high crystallinity of MgO NPs with a crystallite size of 32.6 ± 5 nm while Energy-dispersive X-ray spectroscopy (EDS) analysis highlighted the composition comprises 40.47% Magnesium and 48.64% Oxygen by weight. Fourier transform infrared spectroscopy (FT-IR) revealed characteristic Mg-O bonds through peaks at 560 cm −1 and 866 cm −1 , while Raman spectroscopy affirmed the cubic structure of MgO. Subsequently, the photocatalytic performance of MgO NPs under visible light irradiation was evaluated. Remarkably, the addition of 1 g/L of MgO nano-catalyst resulted in a degradation efficiency of 98% after 110 min on methylene blue dye, showcasing the high catalytic activity of MgO NPs. This remarkable photocatalytic efficiency emphasizes the potential of MgO NPs in environmental remediation.

Background Natamycin is an antifungal polyene macrolide antibiotic with wide applications in health and food industries. Currently, it is the only antifungal food additive with the GRAS status (Generally Regarded as Safe). Results Natamycin production was investigated under the effect of different initial glucose concentrations. Maximal antibiotic production (1.58 ± 0.032 g/L) was achieved at 20 g/L glucose. Under glucose limitation, natamycin production was retarded and the produced antibiotic was degraded. Higher glucose concentrations resulted in carbon catabolite repression. Secondly, intermittent feeding of glucose improved natamycin production due to overcoming glucose catabolite regulation, and moreover it was superior to glucose-beef mixture feeding, which overcomes catabolite regulation, but increased cell growth on the expense of natamycin production. Finally, the process was optimized in 7.5 L stirred tank bioreactor under batch and fed-batch conditions. Continuous glucose feeding for 30 h increased volumetric natamycin production by about 1.6- and 1.72-folds in than the batch cultivation in bioreactor and shake-flasks, respectively. Conclusions Glucose is a crucial substrate that significantly affects the production of natamycin, and its slow feeding is recommended to alleviate the effects of carbon catabolite regulation as well as to prevent product degradation under carbon source limitation. Cultivation in bioreactor under glucose feeding increased maximal volumetric enzyme production by about 72% from the initial starting conditions.