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Search Results: 1 - 10 of 462093 matches for " Emad A. SHALABY "
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Allelopathic Effects of Water Hyacinth [Eichhornia crassipes]
Sanaa M. M. Shanab,Emad A. Shalaby,David A. Lightfoot,Hany A. El-Shemy
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013200
Abstract: Eichhornia crassipes (Mart) Solms is an invasive weed known to out-compete native plants and negatively affect microbes including phytoplankton. The spread and population density of E. crassipes will be favored by global warming. The aim here was to identify compounds that underlie the effects on microbes. The entire plant of E. crassipes was collected from El Zomor canal, River Nile (Egypt), washed clean, then air dried. Plant tissue was extracted three times with methanol and fractionated by thin layer chromatography (TLC). The crude methanolic extract and five fractions from TLC (A–E) were tested for antimicrobial (bacteria and fungal) and anti-algal activities (green microalgae and cyanobacteria) using paper disc diffusion bioassay. The crude extract as well as all five TLC fractions exhibited antibacterial activities against both the Gram positive bacteria; Bacillus subtilis and Streptococcus faecalis; and the Gram negative bacteria; Escherichia coli and Staphylococcus aureus. Growth of Aspergillus flavus and Aspergillus niger were not inhibited by either E. crassipes crude extract nor its five fractions. In contrast, Candida albicans (yeast) was inhibited by all. Some antialgal activity of the crude extract and its fractions was manifest against the green microalgae; Chlorella vulgaris and Dictyochloropsis splendida as well as the cyanobacteria; Spirulina platensis and Nostoc piscinale. High antialgal activity was only recorded against Chlorella vulgaris. Identifications of the active antimicrobial and antialgal compounds of the crude extract as well as the five TLC fractions were carried out using gas chromatography combined with mass spectroscopy. The analyses showed the presence of an alkaloid (fraction A) and four phthalate derivatives (Fractions B–E) that exhibited the antimicrobial and antialgal activities.
Enteromorpha compressa Exhibits Potent Antioxidant Activity
Sanaa M. M. Shanab,Emad A. Shalaby,Eman A. El-Fayoumy
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/726405
Abstract: The green macroalgae, Enteromorpha compressa (Linnaeus) Nees, Ulva lactuca, and E. linza, were seasonally collected from Abu Qir bay at Alexandria (Mediterranean Sea) This work aimed to investigate the seasonal environmental conditions, controlling the green algal growth, predominance, or disappearance and determining antioxidant activity. The freshly collected selected alga (E. compressa) was subjected to pigment analysis (chlorophyll and carotenoids) essential oil and antioxidant enzyme determination (ascorbate oxidase and catalase). The air-dried ground alga was extracted with ethanol (crude extract) then sequentially fractionated by organic solvents of increasing polarity (petroleum ether, chloroform, ethyl acetate, and water). Antioxidant activity of all extracts was assayed using different methods (total antioxidant, DPPH [2, 2 diphenyl-1-picrylhydrazyl], ABTS [2, 2 azino-bis ethylbenzthiazoline-6-sulfonic acid], and reducing power, and β-carotene linoleic acid bleaching methods). The results indicated that the antioxidant activity was concentration and time dependent. Ethyl acetate fraction demonstrated higher antioxidant activity against DPPH method (82.80%) compared to the synthetic standard butylated hydroxyl toluene (BHT, 88.5%). However, the crude ethanolic extract, pet ether, chloroform fractions recorded lower to moderate antioxidant activities (49.0, 66.0, and 78.0%, resp.). Using chromatographic and spectroscopic analyses, an active compound was separated and identified from the promising ethyl acetate fraction.
Enhancement of biodiesel production from different species of algae
El-Moneim M. R. Afify, Abd,Shalaby, Emad A.,Shanab, Sanaa M. M.
Grasas y Aceites , 2010, DOI: 10.3989/gya.021610
Abstract: Eight algal species (4 Rhodo, 1 chloro and 1 phaeophycean macroalgae, 1 cyanobacterium and 1 green microalga) were used for the production of biodiesel using two extraction solvent systems (Hexane/ether (1:1, v/v)) and (Chloroform/ methanol (2:1, v/v)). Biochemical evaluations of algal species were carried out by estimating biomass, lipid, biodiesel and sediment (glycerin and pigments) percentages. Hexane/ ether (1:1, v/v) extraction solvent system resulted in low lipid recoveries (2.3-3.5% dry weight) while; chloroform/methanol (2: 1, v/v) extraction solvent system was proved to be more efficient for lipid and biodiesel extraction (2.5 – 12.5% dry weight) depending on algal species. The green microalga Dictyochloropsis splendida extract produced the highest lipid and biodiesel yield (12.5 and 8.75% respectively) followed by the cyanobacterium Spirulina platensis (9.2 and 7.5 % respectively). On the other hand, the macroalgae (red, brown and green) produced the lowest biodiesel yield. The fatty acids of Dictyochloropsis splendida Geitler biodiesel were determined using gas liquid chromatography. Lipids, biodiesel and glycerol production of Dictyochloropsis splendida Geitler (the promising alga) were markedly enhanced by either increasing salt concentration or by nitrogen deficiency with maximum production of (26.8, 18.9 and 7.9 % respectively) at nitrogen starvation condition. Ocho especies de algas (4 Rhodo, 1 cloro y 1 macroalgas phaeophycean, 1 cianobacteria y 1 microalga verde) fueron utilizados para la producción de biodiesel utilizando dos sistemas de extracción con disolventes (hexano/éter (1:1, v/v)) y (Cloroformo / metanol (2:1, v/v)). La evaluación bioquímica de las especies de algas se llevó a cabo mediante la estimación de los porcentajes de biomasa, de lípidos, de biodiesel y de sedimento (glicerina y pigmentos). El sistema extracción con el disolvente hexano/éter (1:1, v/v) produjo una bajada de los porcentaje de lípidos (2.3-3.5% de peso seco), mientras que el sistema de extracción con el disolvente cloroformo/metanol (2:1, v/v) demostró ser más eficaz en la extracción de los lípidos y del biodiésel (2,5 - 12,5% de peso seco) dependiendo de las especies de algas. Los extractos de microalgas verde Dictyochloropsis splendida produjeron los mayores porcentaje de lípidos y de biodiésel (12,5 y 8,75%, respectivamente), seguida de la cianobacteria Spirulina platensis (9,2 y 7,5% respectivamente). Por otra parte, las macroalgas (rojo, marrón y verde) produce los porcentajes más bajos de biodiesel (0,25 - 3,8%). Los ácidos grasos del biodiesel de
Antioxidant Activity of Aqueous Extracts of Different Caffeine Products
Abd El-Moneim M.R. AFIFY,Emad A. SHALABY,Hossam Saad EL-BELTAGI
Notulae Botanicae Horti Agrobotanici Cluj-Napoca , 2011,
Abstract: The antioxidant activity of water extracts (cold and hot) of six caffeine products were carried out. The extracts were screened for total polyphenol contents and antioxidant activity using DPPH, ABTS methods and reducing power method at 50 and 100 μg/ml after 15 min and 30 min using DPPH, ABTS BHA and Caffeine as standard compounds. The results indicated that, the hot water extracts for different caffeine products showed higher antioxidant activity than those of cold extracts and this activity was time and concentration dependent. In addition, the activity was higher against ABTS radical more than DPPH and reducing power methods. Also, there is a positive correlation between the antioxidant and reducing compounds presented in water extracts of different caffeine products. The results of HPLC showed that fresh tea leaves are rich in flavanol monomers known as catechins. The most abundant catechin derivatives in green tea are EGC, EGCG and GC. On the other hand EGCG and GC are major catechin derivative in different caffeine product except El-Fakher tea and Cacao. Generally, these beverages had high antioxidant capacities and total phenolic contents, and could be important dietary sources of antioxidant phenolic for prevention of diseases caused by oxidative stress.
Cultivating Microalgae in Domestic Wastewater for Biodiesel Production
Soha S.M. MOSTAFA,Emad A. SHALABY,Ghada I. MAHMOUD
Notulae Scientia Biologicae , 2012,
Abstract: The objective of this study was to evaluate the growth of nine species of microalgae (green and blue green microalgae) on domestic waste water samples obtained from Zenein Waste Water Treatment Plant (ZWWTP), Giza governorate, Egypt. The species were cultivated in different kind of waste water; before treatment; after sterilization; with nutrients with sterilization and with nutrients without sterilization. The experiment was conducted in triplicate and cultures were incubated at 25±1°C under continuous shaking (150 rpm) and illumination (2000 Lux) for 15 days. pH, electric conductivity (EC), optical density (OD) , dry weight (DW), were done at the time of incubation and at the end of experiment, in addition to determine the percentage of lipid and biodiesel. The data revealed that, domestic waste water with nutrient media (T3) was promising for cultivation of five algal species when compared with conventional media, Moreover, domestic waste water after sterilization (T2) was selected media for cultivation of Oscillatoria sp and Phormedium sp. However, T1 media (waste water without treatment) was the promising media for cultivation of Nostoc humifusum. The biodiesel produced from algal species cultivated in waste water media ranged from 3.8 to 11.80% when compared with the conventional method (3.90 to 12.52%). The results of this study suggest that growing algae in nutrient rich media offers a new option of applying algal process in ZWWTP to mange the nutrient load for growth and valuable biodiesel feedstock production.
A Particle Swarm Optimization Algorithm for a 2-D Irregular Strip Packing Problem  [PDF]
Mohamed A. Shalaby, Mohamed Kashkoush
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.32024
Abstract:

Two-Dimensional Irregular Strip Packing Problem is a classical cutting/packing problem. The problem is to assign, a set of 2-D irregular-shaped items to a rectangular sheet. The width of the sheet is fixed, while its length is extendable and has to be minimized. A sequence-based approach is developed and tested. The approach involves two phases; optimization phase and placement phase. The optimization phase searches for the packing sequence that would lead to an optimal (or best) solution when translated to an actual pattern through the placement phase. A Particle Swarm Optimization algorithm is applied in this optimization phase. Regarding the placement phase, a combined algorithm based on traditional placement methods is developed. Competitive results are obtained, where the best solutions are found to be better than, or at least equal to, the best known solutions for 10 out of 31 benchmark data sets. A Statistical Design of Experiments and a random generator of test problems are also used to characterize the performance of the entire algorithm.

Dustfall Associated with Dust Storms in the Al-Ahsa Oasis of Saudi Arabia  [PDF]
Emad A. Almuhanna
Open Journal of Air Pollution (OJAP) , 2015, DOI: 10.4236/ojap.2015.42007
Abstract: Dustfall is a major threat to agricultural and industrial infrastructures, as well as to other aspects of livelihood. Dustfall associated to a severe dust storm that hit the Al-Ahsa Oasis of Saudi Arabia during 12-13 March 2014 is discussed in this paper. The storm caused widespread and heavy dust deposition. A dramatic decrease in the visibility coincided with the storm, and the average dust concentrations recorded during a peak 10-hour period were 6772, 5862.4 and 451.1 μg/m3 for total suspended particles (TSP), particulate matter smaller than or equal to 10 μm (PM10) and those smaller than or equal to 2.5 μm (PM2.5), respectively. The lowest visibility was 200 m, and the wind speed increased to 17.5 m/s from the north. The average daily dust deposited in the study area during the event was 12.84 (SD = 1.2) g/(m2?d). The dust samples comprised insoluble dust (48.5%) and soluble dust (51.5%). Based on the Munsell color system, the final color description of the falling dust was 10 YR/6/3. A microphotograph of the dustfall (settleable particulate matter) captured by a stereo dissection microscope shows that the dust particles had various colors and sizes, and they contained fibers and vegetative debris).
Comparison of FT-NIR Transmission and HPLC to Assay Montelukast in Its Pharmaceutical Tablets  [PDF]
Ahmed B. Eldin, Abdalla A. Shalaby
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.28102
Abstract: For several years, near-infrared spectroscopy (NIRS) has become an analytical technique of great interest for the pharmaceutical industry, particularly for the non-destructive analysis of dosage forms. The goal of this study is to show the capacity of this new technique to assay the active ingredient in low-dosage tablets. NIR spectroscopy is a rapid, non-destructive technique and does not need any sample preparation. A prediction model was built by using a partial least square regression fit method. The NIR assay was performed by transmission. The results obtained by NIR spectroscopy were compared with the conventional HPLC method for Montelukast tablets produced by Sigma pharmaceutical corp. The study showed that Montelukast tablets can be individually analyzed by NIR with high accuracy. It was shown that the variability of this new tech- nique is less important than that of the conventional method which is the HPLC with UV detection.
A Review on Mobile and Sensor Networks Innovations in Intelligent Transportation Systems  [PDF]
Emad Felemban, Adil A. Sheikh
Journal of Transportation Technologies (JTTs) , 2014, DOI: 10.4236/jtts.2014.43020
Abstract:

Rapid developments of mobile technologies, data acquisition and big data analytics, and their integration with critical application domains such as transportation systems have the potential to produce more efficient, real-time, intelligent and safe transportation infrastructure. To increase the quality of transportation services, wireless sensor networks, mobile phones, crowd sourcing, RFID and Bluetooth technologies are being used. We surveyed innovations that were transformed from ideas in research labs into commercial systems in practical use. In this paper, we present some innovative mobile technologies, services and platforms that are being used in modern transportation applications including traffic data acquisition, traffic management and control, route optimizations, infrastructure redesign, road safety and enhancing user experience.

Electrochemical Studies and Thermodynamic Parameters of Citrazinic Acid Azo Dye and its Nitro Derivatives in DMF-Aqueous Solutions
Yasin,Shalaby A.;
Portugaliae Electrochimica Acta , 2006,
Abstract: the electrochemical behavior of citrazinic acid azo dye derivatives (i-v) was recorded in aqueous buffer solutions containing 10% (v/v) dmf using dc-polarography and cyclic voltammetry. the dc-polarograms displayed one or two reduction waves depending on the nature of substituent and the ph of the electrolyte solution. the reduction process takes place irreversibly and diffusion controlled at the electrode surface through the uptake of four electron/molecules for compound i and eight electron/molecules for each of compounds ii-v. the recorded cyclic voltammograms displayed two irreversible cathodic peaks at different ph values. the kinetic parameters of the electrode process such as, an, heterogeneous rate constant (ks) and activation energy (δg#) were evaluated and discussed from cyclic voltammetry. also, the electrode reaction mechanism is proposed and discussed. the effect of introducing substituents on the half-wave potential of the reduction process is illustrated. the different thermodynamic parameters such as activation energy (δg#), enthalpy change (δh#) and entropy change (δs#) revealed the endergonic nature of the electrode reaction.
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