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The objective of this study is to confirm the possibility of tracing sources of airborne mineral dust using elemental ratios. The region of study is the north-eastern part of the Sahara where dust compositional data were lacking; 272 mineral dust samples collected at 3 experimental stations of Egypt were analyzed by X-ray fluorescence. Based on the mineral dust concentration, 65% of the samples correspond to moderate (3–10 μg m−3), 22% to medium (10–25 μg m−3), and 13% to intense (> 25 μg m−3) dust events. The Ca/Al and (Mg + Ca)/Fe ratios were found to be strongly correlated and their ranges of variation to cover are more than one order of magnitude, which confirms their interest for the tracing of the dust sources. Using a combination of MODIS satellite observations, HYSPLIT back-trajectory analysis, and simulations with dust emission models, the large (> 6) and intermediate (2–6) Ca/Al ratios were shown to correspond to dust originating from saline playas (chotts) and calcareous surfaces, respectively. Conversely, the lowest (< 2) ratios correspond to dust emitted by siliceous sand seas (ergs). Therefore, a classification of the dust in 3 categories (erg-like, calcareous, and chott-like) based on Ca/Al is proposed. The events of moderate to medium intensity are dominated by chott-like and calcareous dust, which suggests that these sources are activated during erosion events of limited (local) extension. Conversely, the fact that the dust composition is more likely to be of the erg-like type during intense events underlines the dominant role played by sand dune fields during major erosion events. [ABSTRACT FROM AUTHOR]

Heavy metal pollution of agricultural soil has become a major serious concern. The development of suitable control and remediation strategies for heavy metal contaminated soil has become critical. The outdoor pot experiment was conducted to investigate the effect of biochar, zeolite, and mycorrhiza on the bioavailability reduction of heavy metals and its subsequent effects on soil properties and bioaccumulation in plants as well as the growth of cowpea grown in highly polluted soil. Zeolite, biochar, mycorrhiza, zeolite with mycorrhiza, biochar with mycorrhiza, and soil without any modifications were the six treatments used. The experiment was conducted with a completely randomized design and four replications. The results indicated that the combination of biochar with mycorrhiza had the highest values of root and shoot dry weight and the lowest heavy metal concentrations in root and shoot as well as bioconcentration and translocation factors for all heavy metals. The highest significant reductions in the availability of heavy metals over the control were found with biochar with mycorrhiza, which were 59.1%, 44.3%, 38.0%, 69.7%, 77.8%, 77.2% and 73.6% for Cd, Co, Cr, Cu, Ni, Pb and Zn, respectively. The application of biochar and zeolite either alone or in combination with mycorrhiza increased significantly soil pH and EC compared to mycorrhiza treatment and untreated soil. It can be concluded that the combination of biochar and mycorrhizal inoculation has great potential as a cost-effective and environmentally technique for enhancing heavy metal immobilization, lowering heavy metal availability and plant uptake, and improving cowpea plant growth. [ABSTRACT FROM AUTHOR]

The accumulation of trace metals in vegetable field soils is of increasing worry because of the potential health hazards and their detrimental effects on soil ecosystems. To investigate the state of trace metal pollution in vegetable field soils, 60 surface soil samples were collected from vegetable fields across the Eastern Nile Delta region, Egypt. The results concluded that the concentrations of Cu, Mn, and Ni were lesser than their corresponding background values, while the concentrations of Cd, Co, Pb, and Zn were exceeding their background values. The pollution indices showed that the studied soil experienced low to moderate contamination and the Cd and Cr contamination was serious. The hazard index values of nine trace metals signified that there was no adverse non-carcinogenic risk for adults and children. The carcinogenic risk of Cd, Co, Ni, and Pb for both age groups was within acceptable limits, while Cr had critical carcinogenic hazards for children. Overall, the quality of studied soils is relatively safe, although some samples impose serious pollution problems of Cd and Cr. Thus, properly monitored trace metals and soil management action should be applied to reduce further soil pollution in vegetable fields in the Eastern Nile Delta. [ABSTRACT FROM AUTHOR]

For the time being, the creation of surface nano-structures has become an important technological process which plays a paramount role in the electronic devices, as it has a very remarkable feature that they are used in etching without using chemicals. Irradiation of silicon oxide single crystal with slow highly charged ions can produce surface nano-hillocks. The formation mechanism of the created nano-hillocks is a topic of debate. One of the suggested formation mechanisms is a plasma expansion approach. The latter will be used to explain the creation of surface nano-hillocks in silicon oxide single crystal using a fully classical plasma model. For this purpose, classical hydrodynamic ion fluid equations along with Maxwellian or non-Maxwellian electrons distributions are solved numerically to obtain the expansion profiles of the number density, fluid velocity, and electrostatic potential. The relevance of different plasma parameters such as temperature and density ratios, superthermal, and non-extensive parameters is highlighted on the expansion profiles. [ABSTRACT FROM AUTHOR]

Four isolates of F. oxysporum were isolated from different localities in Dakahlia Governorate, Egypt. Isolate 3 was the more aggressive one on pea plant (wilt disease incidence 53.9%). The three fungal products, Trichoderma harzianum, T. viride and yeast extract had potent antagonistic effects, but T. harzianum was the best in inhibition of F. oxysporum linear growth (83.0%). A pot experiment, conducted in winter 2014, showed that the combination of compost with T. harzianum was the most effective for controlling Fusarium wilt (0.0%), followed by the combination of compost with yeast. Growing of pea plant infected with F. oxysporum in soil treated with T. harzianum and compost produced the highest increase in total phenols (93.46 mg phenol/100g fresh wt.) compared to those in control plants (non- infected) (74.59 mg phenol/100g fresh wt.) as well as the greatest increase in the activity of the defensive enzymes: peroxidase, polyphenole oxidase (PPO) and phenyl alanine layase (PAL). A dramatic decrease was obtained in both quantitative (number of pods, fresh and dry weight of pods) and qualitative (total carbohydrates, total soluble sugars: T.S.S, total protein, vitamin C content and crude fiber content) yield parameters of pea plant infected with F. oxysporum compared to non-infected plants. On the other hand, the combination of T. viride, T. harzianum or yeast extract with compost, resulted in a significant increase in all quantitative and qualitative yield parameters. The most significant improvement in yield parameters was in case of pea plants infected with F. oxysporum and grown in soil treated with the compost and T. harzianum. [ABSTRACT FROM AUTHOR]

S. sclerotiorum is a strong and resident soil pathogen with high resistance to synthetic fungicides. The biocontrol agent Trichoderma spp. alone provides moderate control of this fungus. In present study, potassium tartrate, ascorbic acid, folic acid, thiamine and micronutrients mixture were used to improve the number of spores, fresh and dry weights, crude extracts, volatile compounds, and secondary metabolites produced by four isolates of Trichoderma against pathogen. A onetime amendment of thiamine (0.1%) or micronutrients mixture improve the antagonism efficacy of most Trichoderma isolates showing complete prevention of pathogen growth and inhibition of sclerotia formation. [ABSTRACT FROM AUTHOR]

Properties of ion acoustic solitons head-on collision in an ultracold neutral plasma composed of ion fluid and non-Maxwellian electron distributions are investigated. For this purpose, the extended Poincare-Lighthill-Kuo (PLK) method is employed to derive coupled Kortweg-de Vries (KdV) equations describing the system. The nonlinear evolution equations for the colliding solitons and corresponding phase shifts are investigated both analytically and numerically. It is found that the polarity of the colliding solitons strongly depends on the type of the non-Maxwellian distribution (via nonthermal or superthermal electron distributions). Especially the phase shift due to solitons collision is strongly influenced by the non-Maxwellian distribution. A new critical nonthermal parameter β, characterizing the nonthermal electron distribution, and which is not present for superthermal particle distributions, allows the existence of double polarity of the solitons. The phase shift increases below β for compressive solitons, but it decreases above β for rarefactive soliton. For superthermal distribution the phase shift increases rapidly for low spectral index κ, whereas for higher values of κ, the phase shift decreases smoothly and becomes nearly stable for κ>10. Around β and small values of κ, the deviation from the Maxwellian state is strongest, and therefore the phase shift has unexpected behavior due to the presence of more energetic electrons that are represented by the non-Maxwellian distributions. The nonlinear structure, as reported here, could be useful for controlling the solitons that may be created in future ultracold neutral plasma experiments. [ABSTRACT FROM AUTHOR]

Modulation of the adrenergic activity and interfering with channels such as potassium channels may affect relaxation and contraction of the corpus cavernosum. Sildenafil is a selective phosphodiesterase-5 inhibitor, proven effective in treating erectile dysfunction.In this study, the effect of sildenafil citrate on α-receptors modulation and potassium channels was tested. The direct relaxant effect of sildenafil citrate was studied by measuring changes in isometric tension in isolated strips of rabbit corpus cavernosum and rat aortic ring precontracted with phenylephrine or KCl compared to that of diazoxide in the presence and absence of tetraethylammonium. The inhibitory effect of sildenafil on electrical field stimulation-induced contraction of rabbit corpus cavernosum and rat anococcygeus muscle was also studied compared to that of phentolamine. Muscle relaxant effect of sildenafil (1 × 10−9–1 × 10−6 M on phenylephrine-precontracted rabbit corpus cavernosum strips was not attenuated by NG-nitro-L-arginine (3 × 10−5 M). Cumulative addition of sildenafil (1 × 10−9–1 × 10−6 M) and phentolamine (1 × 10−9–1 × 10−6 M) to the organ bath dose-dependently inhibited electrical field stimulation-induced contraction of rabbit corpus cavernosum and rat anococcygeus muscle, with almost similar EC50 values. Sildenafil (1 × 10−7 M) also inhibited phenylephrine-induced contraction of rat aortic rings by 39.83±3.01%. In addition, tetraethylammonium (1 × 10−3 M) significantly attenuated the muscle relaxant effect of sildenafil (1 × 10−9–1 × 10−6 M) on phenylephrine-precontracted strips of rabbit corpus cavernosum.Sildenafil citrate is capable of producing cavernosal smooth muscle relaxation by an additional mechanism that may involve α-receptors and potassium channel opening.International Journal of Impotence Research (2007) 19, 551–557; doi:10.1038/sj.ijir.3901590; published online 2 August 2007 [ABSTRACT FROM AUTHOR]

Summary The Linke TL, Ångström β and Unsworth-Monteith δa turbidity parameters are investigated for two sites in Egypt: Cairo, a densely populated urban area, and Aswan, an arid unpolluted area. These three turbidity parameters are calculated from broadband pyrheliometric measurements recorded hourly over the period 1992–96. Monthly averages of TL, β and δa show relatively flat and identical seasonal variations with a marked main maxima during spring at both sites, due to Khamsin depressions coming from the Great Sahara. A secondary maximum is observed at Aswan in summer, due to dust haze which prevails during that season, and at Cairo in autumn, due to the northern extension of the Sudan monsoon trough, which is accompanied by small scale depressions with dust particles. Annual mean values of TL, β and δa (5.59, 0.250 and 0.372, respectively) at Cairo are larger than at Aswan (3.89, 0.139 and 0.213, respectively). In the same way, the seasonal mean values of TL, β and δa at Cairo are larger than at Aswan. More generally, the monthly and yearly average turbidity values are significantly larger in Cairo than in Aswan for the whole period 1992–96, which is attributable in part to the urbanization/industrialization effect of Cairo. An estimate of the corresponding overburden is obtained by comparison between the present data and older TL data from 1922–27. It is also shown that turbidity over both sites is largest during 1992, just after the eruption of Mount Pinatubo in 1991. The dependence of β on some meteorological parameters such as wind speed and direction, precipitable water, relative humidity, temperature and visibility, is also analyzed. This reveals in particular that visibility is not a good predictor of turbidity at either site. Conversely, the wind direction and speed have a definite effect on turbidity, and consequently, largest turbidities occur when the wind carries aerosols from the main industrial particle source areas around Cairo. For any season of the year, the average turbidity at the latter site is larger than that at other big cities such as Athens, Rome, and Toronto, but is lower than at Dhahran, Saudi Arabia. [ABSTRACT FROM AUTHOR]