النشر العلمي

  • Evidence for Additional Pheromonal Components Mediating Oviposition Aggregation in Schistocerca gregaria

Oviposition responses of gregarious adult gravid females of the desert locust Schistocerca gregaria to sand previously used for oviposition by gregarious females (contaminated sand, with eggs and froth removed) and to sterilized sand (noncontaminated sand) were compared in bioassays. Gregarious females preferentially oviposited into contaminated sand. The number of egg pods laid by the females was found to correlate with the frequency of use of the contaminated sand for oviposition. Charcoal-trapped volatiles from the contaminated sand also elicited similar responses from gregarious females. Gas chromatography–electroantennographic detection (GC-EAD) analysis of the trapped volatiles revealed the presence of three electrophysiologically active compounds that were identified by GC-MS as (Z)-6-octen-2-one, (E,E)-3,5-octadien-2-one and its geometric isomer (E,Z)-3,5-octadien-2-one. The relative amounts of the three EAG-active compounds in the volatiles increased with consecutive oviposition by the gregarious females. These results indicate mediation of additional pheromonal components in the oviposition behavior of gregarious desert locust that are distinct from those that were previously identified in the froth volatiles.

published in Journal of Chemical Ecology, 1999, Volume 25, Number 4, Pages 835-845

  • Semiochemical modulation of oviposition behaviour in the gregarious desert locust Schistocerca gregaria†

Bioassays have shown that sand freshly contaminated by ovipositing females of the gregarious desert locust Schistocerca gregaria (Forskal) is more effective in inducing further oviposition from conspecifics than contaminated sand stored for three or six months, which contrasts with results obtained previously with Locusta migratoria (Reiche & Farmaire). The activity of contaminated sand correlated with the levels of three unsaturated aliphatic ketones, (Z)-6-octen-2-one, (E,E)-3,5-octadien-2-one and its geometric isomer (E,Z)-3,5-octadien-2-one present in the volatile emissions from the sand.

published in Pesticide ScienceVolume 55, Issue 5, pages 570–571,

  • Determination of Insecticide Residues in Okra Fruit Wash using Mosquito Larvae as Bio-indicator

 

ABSTRACT

A study was conducted to determine insecticide residues in okra (Abelmoschus esculentus L) fruits by using mosquito (Anopheles arabiensis Patton) larvae 3rd or early 4th instar as a bio-indicator a tool instead of high technology and costly analytical equipment. Mortality was evaluated by taking 10 larvae/replicate (3 replicates/concentration) and each experiment was repeated thrice to obtain the Probit model used later in the field study to calculate the residues. The insecticide residues in tape water fruit wash of okra fruits collected from the field were investigated by using the mosquito larvae from day 1 to day 10 after insecticide application. The results were subjected to the equation of the regression line for each insecticide used, as the Probit model, to calculate the concentration of these insecticides in okra fruits collected from the sprayed field. The residues were measured from 250 g and 1 kg of fruits as mg/g okra fruit. Malathion and cypermethrin residues in the 0.25 kg batches and 1 kg batches were found below the Acceptable Daily Intake (ADI) of 0.02mg/kg body weight and 0.05mg/kg body weight, respectively, while imidacloprid was above the ADI (0.06mg/kg body weight) in day 1 - day 6, but was equal to ADI in day 2 for the 0.25 kg batches, and below the ADI for the rest of the days. Regarding the 1 kg batches, the imidacloprid was found above the ADI in days 1, 2, 3, and 4, equal to the ADI in days 5 and 6, and below ADI in 7, 8, 9, and 10 days.

 

Key words: Bio indicator, Cypermethrin, Imidacloprid, Insecticides, Malathion, Mosquito larvae, Okra, Residues

published in 7th International SEANAC Conference

  • Lead Levels in the Urine of Males and Females from Different Age-groups in an Agricultural Village and Sugar-producing Town

Lead (Pb) is one of the most serious environmental poisons all-over the world. Exposure to Pb results in health hazards. This
study aimed to determine the levels of Pb in urine among adult males, females and children ≤ 5, in Rigwa village (agricultural) and
Wadelsayed village (neighboring the Genaid Sugar Factory; established 1963), Gezira State, central Sudan, and compare them with
the international and regional limits. The study age groups were 15 - 20, 25 - 35, 40 - 50 and 55 - 65 yr-old. Urine samples collected
from these groups were analyzed using AAS. Results revealed presence of Pb in all collected samples. Pb levels in urine of females in
Rigwa were 0.343, 0.099, 0.092, 0.138 and 0.2 mg/L, for age groups ≤ 5, 15 - 20, 25 - 35, 40 - 50 and 55 - 65 yr-old, respectively. The
respective levels in males were 0.162, 0.11, 0.103, 0.19 and 0.298 mg/L. On the other hand, for Wadelsayed, the levels in the urine
of females were 0.336, 0.117, 0.211, 0.317 and 0.148 mg/L, respectively, for same five age categories. However, following the same
order of age, Pb levels in urine of males were 0.101, 0.049, 0.089, 0.4 and 0.198 mg/L. In most cases females urine showed higher
levels than males. Wadelsayed showed higher levels than the agricultural village.
Keywords: Heavy Metals; Lead; Urine; Professions; Gezira State; Genaid Sugar Factory, Suda

published in EC Pharmacology & Toxicology 5(1): 13-20

  • Invariant Solutions for a Class of Perturbed Nonlinear Wave Equations

Approximate symmetries of a class of perturbed nonlinear wave equations are computed using two newly-developed methods. Invariant solutions associated with the approximate symmetries are constructed for both methods. Symmetries and solutions are compared through discussing the advantages and disadvantages of each method.

published in MDPI Mathematics

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