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"Mohamed, Ali"
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Gaining-sharing knowledge based algorithm for solving optimization problems: a novel nature-inspired algorithm
This paper proposes a novel nature-inspired algorithm called Gaining Sharing Knowledge based Algorithm (GSK) for solving optimization problems over continuous space. The GSK algorithm mimics the process of gaining and sharing knowledge during the human life span. It is based on two vital stages, junior gaining and sharing phase and senior gaining and sharing phase. The present work mathematically models these two phases to achieve the process of optimization. In order to verify and analyze the performance of GSK, numerical experiments on a set of 30 test problems from the CEC2017 benchmark for 10, 30, 50 and 100 dimensions. Besides, the GSK algorithm has been applied to solve the set of real world optimization problems proposed for the IEEE-CEC2011 evolutionary algorithm competition. A comparison with 10 state-of-the-art and recent metaheuristic algorithms are executed. Experimental results indicate that in terms of robustness, convergence and quality of the solution obtained, GSK is significantly better than, or at least comparable to state-of-the-art approaches with outstanding performance in solving optimization problems especially with high dimensions.
Journal Article
Eco-friendly fabrication of copper oxide nanoparticles using peel extract of Citrus aurantium for the efficient degradation of methylene blue dye
This study presents a simple, sustainable, eco-friendly approach for synthesizing copper oxide (CuO) nanoparticles using
Citrus aurantium
peel extract as a natural reducing and stabilizing agent. The synthesized CuO and CuO-OP were characterized using various techniques, including surface area measurement (S
BET
), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), and high resolution transmission electron microscope (HRTEM). DRS analysis determines band gap energy (E
g
) of 1.7 eV for CuO and 1.6 eV for CuO-OP. FTIR confirmed the presence of Cu–O bond groups. The XRD and HRTEM results revealed monoclinic and spherical nanostructures, with average particle sizes ranging from 53.25 to 68.02 nm, as determined via Scherer’s equation. EDX analysis indicated incorporation of carbon (1.6%) and nitrogen (0.3%) from the peel extract. The synthesized CuO and CuO-OP NPs exhibited excellent photocatalytic efficiencies for methylene blue dye under UV irradiation, reaching 95.34 and 97.5%, respectively, under optimal conditions; the initial dye concentration was 100 mg/L, the pH was 10, the catalyst dosage was 1 g/L, and the contact time was 120 min. Isothermal studies showed that the adsorption of MB onto the nanoparticles followed the Freundlich isotherm model (R
2
= 0.97 and 0.96). Kinetic studies indicated that the degradation followed pseudo-first-order kinetics, with rate constants (K
1
) of 0.0255 min
−1
for CuO and 0.033 min
−1
for CuO-OP. The sorption capacities were calculated as 98.19 mg/g for CuO and 123.1 mg/g for CuO-OP. The energy values obtained from the Dubinin–Radushkevich isotherm were 707.11 and 912.87 KJ mol
−1
, suggesting that chemisorption was the dominant mechanism.
Journal Article
Timing of maternal death: Levels, trends, and ecological correlates using sibling data from 34 sub-Saharan African countries
Millennium Development Goal 5 has not been universally achieved, particularly in sub-Saharan Africa. Understanding whether maternal deaths occur during pregnancy, childbirth, or puerperium is important to effectively plan maternal health programs and allocate resources. Our main research objectives are to (1) describe the proportions and rates of mortality for the antepartum, intrapartum, and postpartum periods; (2) document how these trends vary by sub-region; and (3) investigate ecological correlations between these rates and maternal care interventions. We used data from the Demographic and Health Survey program, which comprises 84 surveys from 34 sub-Saharan African countries conducted between 1990 and 2014. We calculated age-standardized maternal mortality rates and time-specific maternal mortality rates and proportions, and we assessed correlations with maternal care coverage. We found high levels of maternal mortality in all three periods. Time-specific maternal mortality rates varied by country and region, with some showing an orderly decline in all three periods and others exhibiting alarming increases in antepartum and postpartum mortality. Ecological analysis showed that antenatal care coverage was significantly associated with low antepartum mortality, whereas the presence of a skilled attendant at childbirth was significantly associated with low postpartum mortality. In sub-Saharan Africa, maternal deaths occur at high rates in all three risk periods, and vary substantially by country and region. The provision of maternal care is a predictor of time-specific maternal mortality. These results confirm the need for country-specific interventions during the continuum of care to achieve the global commitment to eliminating preventable maternal mortality.
Journal Article
Increasing the performance of cucumber (Cucumis sativus L.) seedlings by LED illumination
Light is one of the most important limiting factors for photosynthesis and the production of plants, especially in the regions where natural environmental conditions do not provide sufficient sunlight, and there is a great dependence on artificial lighting to grow plants and produce food. The influence of light intensity, quality, and photoperiod on photosynthetic pigments content and some biochemical and growth traits of cucumber seedlings grown under controlled conditions was investigated. An orthogonal design based on a combination of different light irradiances, ratio of LEDs and photoperiods was used. Treaments consisted of three light irradiance regimes (80, 100, and 150 µmol m
−2
s
−1
) provided by light-emitting diodes (LEDs) of different ratios of red and blue (R:B) (30:70, 50:50, and 70:30) and three different photoperiods (10/14, 12/12, and 14/10 h). The white light was used as a control/reference. Plant height, hypocotyl length, stem diameter, leaf area, and soluble sugar content were highest when exposed to LM9 (150 µmol m
−2
s
−1
; R70:B30; 12/12 h) light mode, while the lowest values for the above parameters were obtained under LM1 (80 µmol m
−2
s
−1
; R30:B70; 10/14 h). Higher pigments contents (chlorophyll
a
, chlorophyll
b
, and carotenoid) were obtained when light regime LM9 (150 µmol m
−2
s
−1
; R70:B30; 12/12 h) was applied. In general, cucumber seedlings grown under the LM9 regime showed a significant increase in growth as well as photosynthetic capacity. It seems that the content of photosynthetic pigments is the key factor responsible for the performance of cucumber seedlings grown under different lighting modes, compared to other traits studied. We recommend monitoring the content of chlorophyll
a, b
, and their ratio value when studying the light requirement of cucumber plants.
Journal Article
Anticancer activity of biostabilized selenium nanorods synthesized by Streptomyces bikiniensis strain Ess_amA-1
Selenium is an important component of human diet and a number of studies have declared its chemopreventive and therapeutic properties against cancer. However, very limited studies have been conducted about the properties of selenium nanostructured materials in comparison to other well-studied selenospecies. Here, we have shown that the anticancer property of biostabilized selenium nanorods (SeNrs) synthesized by applying a novel strain Ess_amA-1 of Streptomyces bikiniensis. The strain was grown aerobically with selenium dioxide and produced stable SeNrs with average particle size of 17 nm. The optical, structural, morphological, elemental, and functional characterizations of the SeNrs were carried out using techniques such as UV-vis spectrophotometry, transmission electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectrophotometry, respectively. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed that the biosynthesized SeNrs induces cell death of Hep-G2 and MCF-7 human cancer cells. The lethal dose (LD50%) of SeNrs on Hep-G2 and MCF-7 cells was recorded at 75.96 μg/mL and 61.86 μg/mL, respectively. It can be concluded that S. bikiniensis strain Ess_amA-1 could be used as renewable bioresources of biosynthesis of anticancer SeNrs. A hypothetical mechanism for anticancer activity of SeNrs is also proposed.
Journal Article