Abstract. Synthetic insecticides and other xenobiotic compounds are usually used to abate the effects of insect pests/vectors of agricultural and medical importance by adversely affecting the insects. The xenobiotics are also capable of inducing the expression of detoxification genes such as the cytochrome P450 (CYP) gene in targeted insects like mosquitoes (Feyereisen, 2012). The high expression levels of CYPs in insecticide-resistant and exposed mosquitoes have been linked with a potential role in xenobiotic resistance. This study investigated the induction potential of leaf litter infusions and insecticides on the expressions of CYP4H28v2 and CYP4H31v2 in the dengue mosquito Aedes aegypti using Reverse Transcription-quantitative Polymerase Chain Reaction. Exposure of Ae. aegypti larvae to leaf litter infusions demonstrated that CYP4H28v2 and CYP4H31v2 were significantly induced by Lagerstroemia speciosa but not Ficus benjamina, Plumeria obtusa, Millettia pinnata and Pithecellobium dulce. None of the genes was significantly highly expressed in adult females exposed to d-allethrin and d-trans allethrin products. CYP4H28v2 was significantly induced in Ae. aegypti exposed to DDT, malathion and permethrin for both 5 and 10 min. DDT, malathion and permethrin significantly induced CYP4H31v2 only in Ae. aegypti exposed to the insecticides for 10 min. Exposure to the insecticides for 5 min displayed different levels of CYP4H31v2 expression with significantly higher (DDT-exposed) and lower (permethrin-exposed) levels in the mosquito. The results show that natural and synthetic xenobiotics can induce significant expression of CYP4H28v2 and CYP4H31v2 in the mosquito, indicating the potential role of the genes in mediating xenobiotic resistance. This may enhance the survival capabilities of the mosquito when in contact with phytotoxins of leaf litter in their natural ecosystem and synthetic insecticides in adulticide spray regimens.

Artificial neural network (ANN) is one of the most advanced technology fields, which allows the machine to learn from the examples in a manner similar to the human brain learning. ANN applied to many fields such as function approximation, data processing, classification, signal demodulation and much more. One of the main problems in the communication field is the effect of noise into the transmitted signal. In this thesis an Artificial Neural Network Demodulator (NND) to demodulate quadrature amplitude modulating signal (QAM) is proposed, this project attempts to develop communication systems by developing neural networks and machine learning. This project will help giving contribution to reduce the error bits, optimize the quality of received data and optimize (NNDs).

The present work reports a facile approach to the one-pot solution growth of vertically

aligned, doped ZnO nanorod (NR) arrays by chemical bath deposition (CBD). The effects of

dopant ions on the final morphologies, electronic band structures and donor densities of

ZnO NRs were examined. With the introduction of dopants, the optical band gap energies

of the samples were reduced. The photoelectrochemical (PEC) water splitting performances

of the doped ZnO NRs were tested. When compared with pristine ZnO NRs, the doped ZnO

NRs demonstrated an improvement of at least 15% in the PEC water splitting activity. Nadoped ZnO NRs was the most efficient photoanode, where its photocurrent density was 2.1

times greater than that of pristine ZnO NRs. The mechanism for improved PEC performance was proposed

Abstract and figures

We performed a comprehensive study of trichomes considering the medicinal importance of the essential oils produced in glandular trichomes of Salvia aegyptiaca L. and lack of data about leaf trichome characteristics. Micromorphological and histochemical analyses of the trichomes of S. aegyptiaca were carried out using light and scanning electron microscopy. We report that the leaves contained abundant non-glandular unbranched trichomes and two types of glandular trichomes, peltate and capitate, on both leaf surfaces. The abaxial leaf side was covered with numerous peltate and capitate trichomes, while capitate trichomes were more abundant on the adaxial leaf side, where peltate trichomes were rarely observed. The non-glandular trichomes were unicellular papillae and multicellular, uniseriate, two-to-six-celled, erect or slightly leaning toward the epidermis. Peltate trichomes were composed of a basal cell, a short cylindrical stalk cell and a broad head of eight secretory cells arranged in a single circle. Capitate trichomes consisted of a one-celled glandular head, subtended by a stalk of variable length, and classified into two types: Capitate trichomes type I (or short-stalked glandular trichomes) and capitate trichomes type II (or long-stalked glandular trichomes). Histochemical tests showed that the secreted material in all types of S. aegyptiaca glandular trichomes was of a complex nature. Positive reactions to lipids for both types of glandular trichomes were obtained, with especially abundant secretion observed in peltate and capitate trichomes type II.

• Cereal and its products can be contaminated with fungi in the field, during drying, processing, transportation and subsequent storage, which may lead to secretion of mycotoxins under favourable condition. The aim of this study was the isolation and identification of some fungi associated with four kinds of Libyan food products of different trademarks. Twenty four (24) samples of couscous, macaroni, wheat flour and rice regularly used for human consumption by Libyan family were collected from local markets in the city of Alzawia, west of Tripoli, Libya. The results reveal isolation of 113 isolates belonging to nine genera: Penicillium, Aspergillus, Fusarium, Paecilomyces, Alternaria, Rhizopus, Mucor, Scopulariopsis and Cladosporum. Approximately 24 species were identified to belong to those isolated genera, several of which are known as main producer of mycotoxins especially A. flavus which are known to produce aflatoxins, Aspergillus niger, Aspergillus carbonarious, Penicillium chrysogenum and Penicillium verrucosum known to produce ochratoxin and Fusarium oxysporum and Fusarium chlamydosporum known to produce fumonisins and trichothecenes. Certainly, the occurrence of such types of mycotoxins can pose a health threatening risk for the consumer of those food items. Presence of these fungi in food products could be due to lack of good agriculture and food manufacturing practices throughout the food chain.
• Key words: Couscous, macaroni, wheat flour, rice, fungi, Libya.

Background

The use of mosquito coils is a common method of protection against mosquito bites and mosquito borne diseases. These coils are widely marketed and used by households in Malaysia to prevent mosquito associated problems.

Objective

To determine the bioefficacy of commercial d-allethrin and d-trans allethrin spatial repellents against the dengue vector Aedes aegypti.

Method

We evaluated the knockdown and mortality effects of spatial repellents containing d-allethrin (0.3% w/w) and d-trans allethrin (0.1% and 0.15% w/w) on Ae. aegypti in a Peet Grady Chamber, relative to a reference product (0.2% w/w d-allethrin).

Results

The spatial repellent containing 0.3% d-allethrin had the shortest knockdown times (KT₅₀ and KT₉₀) and these were significantly different from the other products including the reference coil except the 0.15% d-trans allethrin coil. The spatial repellent containing 0.3% d-allethrin elicited a mortality response of 96%, which was significantly different from the mortality response to the other coils, except for the 0.15% d-trans allethrin formulation.

Conclusions

Spatial repellents containing 0.3% d-allethrin or 0.15% d-trans allethrin had higher efficacies against Ae. aegypti than repellents containing 0.2% w/w d-allethrin or 0.1% d-trans allethrin and their use by households could offer better relief from Ae. aegypti

Abstract

Aims: In the present work, the Libyan wild-growing Thymus capitatus essential oil (EO) was evaluated for its biological properties.

Methods and results: Carvacrol (68.19%) and thymol (12.29%) were found to be the main compounds of the oil. Antioxidant properties, determined by 2,2-diphenylpicrylhydrazyl (DPPH) assay, revealed that IC50 values were 119, 403 and 105 μg ml(-1) for oil, thymol and carvacrol respectively. Microdilution method showed strong antibacterial and especially antifungal potential. Tetrazolium (MTT) colorimetric assay indicated moderate cytotoxicity towards human cell lines MRC-5, HCT 116 and HT-29 (IC50 = 30-150 μg ml(-1)). In adhesion-inhibition assay oil and main compounds reduced adhesion of Escherichia coli and Listeria monocytogenes on colon cells HT-29 (51 and 39% of inhibition against L. monocytogenes and E. coli respectively).

Conclusions: Essential oil of Th. capitatus showed moderate cytotoxic activity, together with excellent antimicrobial effect, in particular against fungi, and significant potential to reduce pathogen colonization in colon.

Abstract: The essential oils obtained by hydrodistillation from the aerial parts of Artemisia judaica L., Artemisia herbaalba Asso. and Artemisia arborescens L. (cultivated) from Libya, were analyzed by GC and GC-MS. The antimicrobial properties were determined using the broth microdilution method against eight bacterial species: Bacillus cereus (clinical isolate), Micrococcus flavus (ATCC10240), Listeria monocytogenes (NCTC7973), Staphylococcus aureus (ATCC6538), Escherichia coli (ATCC35210), Pseudomonas aeruginosa (ATCC27853), Salmonella typhimurium (ATCC13311), Enterobacter cloacae (human isolates) and eight fungal species: Aspergillus niger (ATCC6275), A. ochraceus (ATCC12066), A. versicolor (ATCC11730), A. fumigatus (ATCC1022), Penicillium ochrochloron (ATCC9112), P. funiculosum (ATCC10509), Trichoderma viride (IAM5061) and Candida albicans (human isolate). The major constituents of A. arborescens oil were sesquiterpene hydrocarbons (47.4%). Oxygenated monoterpenes were the dominant constituents in the A. judaica and A. herba-alba oils (54.2% and 77.3%, respectively). Camphor (24.7%) and chamazulene (20.9%) were the major components in the essential oil of A. arborescens, chrysanthenone (20.8%), cis-chrysanthenyl acetate (17.6%) and cis-thujone (13.6%) dominated in the A. herba-alba oil, and the major constituents in the A. judaica oil were piperitone (30.21%) and cis-chrysanthenol (9.1%). The best antimicrobial activity was obtained for A. judaica oil and the lowest effect was noticed in A. arborescens oil. The effect of the tested oils was higher against Gram (+) than Gram (-) bacteria. All three oils showed the best antibacterial activity against Listeria monocytogenes and the lowest against Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, compared to streptomycin and ampicillin. All three oils showed better antifungal activities than ketoconazole, except A. arborescens oil against Aspergillus niger. Keywords: Artemisia judaica; Artemisia herba-alba; Artemisia arborescens; essential oils; antimicrobial activity

Mosquito coils are insecticides commonly used for protection against mosquitoes due to their toxic effects on mosquito populations. These effects on mosquitoes could induce the expression of metabolic enzymes in exposed populations as a counteractive measure. Cytochrome P450 family 4 (CYP4) are metabolic enzymes associated with a wide range of biological activities including insecticide resistance. In this study, the efficacies of three commercial mosquito coils with different pyrethroid active ingredients were assessed and their potential to induce the expression of CYP4 genes in Aedes albopictus analyzed by real-time quantitative PCR. Coils containing 0.3 % d-allethrin and 0.005 % metofluthrin exacted profound toxic effects on Ae. albopictus, inducing high mortalities (≥90 %) compared to the 0.2 % d-allethrin reference coil. CYP4H42 and CYP4H43 expressions were significantly higher in 0.3 % d-allethrin treated mosquitoes compared to the other treated populations. Short-term (KT50) exposure to mosquito coils induced significantly higher expression of both genes in 0.005 % metofluthrin exposed mosquitoes. These results suggest the evaluated products provided better protection than the reference coil; however, they also induced the expression of metabolic genes which could impact negatively on personal protection against mosquito.

Aromatic plant species of genus Thymus are important medicinal plants, highly recommended due to a range of therapeutic properties of their essential oils, commonly known as thyme oil: antirheumatic, antiseptic, antispasmodic, antimicrobial, cardiac, carminative, diuretic and expectorant. The oil is also beneficial in boosting the immune system and helps to fight colds, flu, infectious diseases and chills. It is proved to be a urinary antiseptic, being very helpful for cystitis and urethritis. Scientific validation of traditional uses, and phytochemical and bioactivity evaluation of essential oils from Thymus serpyllum, Thymus algeriensis and Thymus vulgaris were performed.

GC/MS analysis revealed thymol as a major component of T. algeriensis, T. vulgaris and T. serpyllum, with its contribution to the oil 56.0%, 48.9% and 38.5%, respectively. All three essential oils (EOs) exhibited a significant antimicrobial activity against all