Evaluation of the chemical composition and antimicrobial activity of Mentha pulegium,Juniperus phoenicea,and Cyperus longus essential oils from Morocco

The present study evaluates the chemical composition and antimicrobial activity of the essential oils (EOs) of Mentha pulegium L., Juniperus phoenicea L. and Cyperus longus L. from Morocco. The composition of these species was analyzed by GC/MS and 84 components were identified. M. pulegium EO showed a great similarity with EOs coming from other regions, as pulegone, the major component, accounted for about 70% of the EO. The EO of J. phoenicea had as main components α-pinene (24.9%), β-phellandrene (24.4%) and α-terpinyl acetate (12.9%). The EO extracted from C. longus was remarkably rich in sesquiterpene hydrocarbons (83.2%), which included β-himachalene (46.6%), α-humulene (16.9%), and γ-himachalene (10.1%). The antimicrobial activity of these EOs has been evaluated against seven bacteria of significant importance for food hygiene. According to the results, M. pulegium showed the best bacteriostatic and bactericidal effect, followed by J. phoenicea and C. longus. So far as we know, this is the first report on the quantitative composition and biological activity of the essential oil from C. longus. The tested EOs showed a variable degree of antimicrobial activity being M. pulegium the most effective one.     

Solvent extraction of gold by LIX 79: experimental equilibrium study

The extraction of gold(I) from aurocyanide aqueous solutions using LIX 79 has been studied. Different variables that could affect the extraction system were evaluated: equilibration time, aqueous pH, metal and extractant concentrations, organic phase diluent and aqueous ionic strength. The extraction of the aurocyanide complex with respect to other metal‐cyano complexes has also been studied on both synthetic and real leach solutions. Gold experimental data have been analysed numerically to determine the stoichiometry of extracted species and its equilibrium constant. It was found that gold(I) was extracted into the organic phase by the formation of the species RHAu(CN)₂ (LIX 79=R). Stripping of gold from loaded organic phases was carried out using NaOH or NaCN solutions. © 1999 Society of Chemical Industry     

Physicochemical properties and cellular toxicity of (poly)aminoalkoxysilanes-functionalized ZnO quantum dots

Luminescent ZnO nanocrystals were synthesized by basic hydrolysis of Zn(OAc)(2) in the presence of oleic acid and then functionalized with (poly)aminotrimethoxysilanes in the presence of tetramethylammonium hydroxide to render the QDs water-dispersible. The highest photoluminescence quantum yield (17%) was achieved using N(1)-(2-aminoethyl)-N(2)-[3-(trimethoxysilyl)propyl]-1,2-ethanediamine as surface ligand. Transmission electron microscopy and powder x-ray diffraction showed highly crystalline materials with a ZnO nanoparticle diameter of about 4?nm. The cytotoxicity of the different siloxane-capped ZnO QDs towards growing Escherichia coli bacterial cells was evaluated in MOPS-minimal medium. Although concentrations of 5?mM in QDs caused a complete growth arrest in E.?coli, siloxane-capped ZnO QDs appeared weakly toxic at lower doses (0.5 or 1?mM). The concentration of bioavailable Zn (2+) ions leaked from ZnO QDs was evaluated using the biosensor bacteria Cupriavidus metallidurans AE1433. The results obtained clearly demonstrate that concentrations of bioavailable Zn(2+) are too low to explain the inhibitory effects of the ZnO QDs against bacteria cells at 1?mM and that the siloxane shell prevents ZnO QDs from dissolution contrary to uncapped ZnO nanoparticles. Because of their low cytotoxicity, good biocompatibility, low cost and large number of functional amine end groups, which makes them easy to tailor for end-user purposes, siloxane-capped ZnO QDs offer a high potential as fluorescent probes and as biosensors.     

In vitro antifungal activity and chemical composition of Warionia saharae essential oil against 3 apple phytopathogenic fungi

Essential oil of aerial parts of Warionia saharae was obtained by hydrodistillation and analyzed by GC and GC-MS. Thirty-nine compounds were identified, accounting for 93.2% of the total oil. β-Eudesmol (34.9%), nerolidol-E (23%), and linalool (15.2%) were the most abundant components. The antifungal activity of the W. saharae oil was tested by poisoned food (PF) technique and the volatile activity (VA) assay against 3 phytopathogenic causing the deterioration for apple. The results indicated that the W. saharae oil inhibited significantly the mycelial growth of all strains tested (p<0.05). The minimum inhibitory concentration against Alternaria sp. was 2 μL/mL air in VA assay, whereas >2 μL/mL in PF technique for all strains. Fungal spore production was completely inhibited at 1 μL/mL air for Alternaria sp. and at 2 μL/mL air for Penicillium expansum and Rhizopus stolonifer.     

Optimum energy efficient multi-hop protocol for homogenous and heterogeneous 3D underwater acoustic sensor networks

Information transmission is extremely challenging in underwater acoustic sensor networks (UASNs) because, in the acoustic channel, the packet loss is high compared to other channels due to low bandwidth and a long propagation delay. So, designing an efficient energy algorithm is a big challenge in the acoustic channel. In this paper, first, a cluster head (CH) election fitness function based on a hybrid particle swarm optimization and gravitational search algorithm (PSO-GSA) is proposed for a three-dimensional (3D) underwater sensor network (UASN). The proposed algorithm includes CH election, CH load, and neighbor CH distance for multi-hop transmission (MH-PSOGSA). Then, based on the proposed algorithm, a relay-based traffic-aware energy-efficient routing protocol (R-TAEERP) with a weight function is proposed to offload the heavy consumption of the CHs. MATLAB simulations were accomplished to compare the performance of MH-PSOGSA and R-TAEERP with the existing representative protocols. The heterogeneity in energy and traffic has been considered. The simulation results show better performance of the proposed algorithm than other existing representative protocols in terms of energy consumption, the performance of the stable region, and the lifetime of the network.     

Interval Schemes for Singularly Perturbed Initial Value Problems

The modified exponential interval schemes are introduced for the solution of singularly perturbed initial value problems. We give the outline of constructing the schemes of k-th order, then we construct four schemes for k = 1 and k = 2. These schemes are uniformly convergent of second and third order accuracy. Also, we introduce the idea of optimal convergence. Numerical results and comparisons with other schemes are presented.     

c-MYC amplification in a case of progression from MDS to AML (M2)

Serious side effects of photodynamic therapy (PDT) are rare (A.L. Abramson, M.J. Shikowitz, V.M. Mullooly, Clinical effects of photodynamic therapy on recurrent laryngeal papillomas, Arch. Otolaryngology Head Neck Surg., 118 (1992) 25-29; A.L. Abramson, M.J. Shikowitz, Clinical exacerbation of systemic lupus erythematosus after photodynamic therapy of laryngotracheal papillomatosis, Laser Surg. Med., 13 (1993) 677-679). The most frequent side effects of PDT are hypersensitive skin reactions, local edema, nausea, a metallic taste and liver-toxicity (J. Feyh, E. Kastenbauer, Treatment of laryngeal papillomatosis with photodynamic laser therapy, Laryngorhinootologie, 71 (1992) 190-192; J. Feyh, R. Gutmann, A. Leunig, Die Photodynamische Therapie im Bereich der Hals-, Nasen-, Ohrenheilkunde Laryngorhinootologie, 72(6) (1993) 273-78; M.S. Kavuru, A.C. Mekta, Treatment of recurrent respiratory papillomatosis, N. Engl. J. Med., 326 (1992) 204-205; B.L. Wenig, D.M. Kurtzmann, Photodynamic therapy in the treatment of squamous cell carcinomas of the head and neck, Arch. Otolaryngol Head Neck Surg., 116 (1990) 1267-1270). In this case a patient (aged 57 years) suffering from a recurrent larynx papillomatosis was treated with PDT. He was sensitized with Photosan 3 (DHE) 2.5 mg kg-1 body weight, 24 h prior to photoradiation. As a light source, an argon dye laser, operating at a wavelength of 630 nm was used, coupled with a cylindrical light applicator. After treatment the patient was admitted to an intensive care unit for 24 h. 3 h after photoradiation, general urticarial wheals arose, as well as tachycardia and a decrease in blood pressure followed by all the signs of serious anaphylaxis. 1.5 h after treatment with adrenaline and cortisone and stabilization of the cardiac and circulatory situation no more skin lesions were visible.     

Electrophysiological and field activity of halogenated analogs of (E,E)-8,10-dodecadien-1-ol,the main pheromone component,in codling moth (Cydia pomonella L.)

Pest monitoring and control of the codling moth,Cydia pomonella L., have been developed using the main pheromone component of this species, (E,E)-8,10-dodecadienol (codlemone). However, the activity of codlemone is not satisfactory for pest control by mating disruption. Thus, we have synthesized halogenated analogs of codlemone to see if they could be used as new agents for pest control of the codling moth. Their biological activity was measured by electrophysiological techniques. In EAG screening, codlemone was the most active compound. F(10,11)-codlemone [(E,E)-10,11-difluoro-8,10-dodecadienol] and Cl-codlemone [(E,E)-11-chloro-8,10-undecadienol] elicited significant EAG responses, F(10,11)-codlemone triggering responses not significantly different from responses to codlemone. EAG cross-adaptation experiments and single sensillum recordings revealed that these compounds were detected by the same receptor neuron type as codlemone. No competitive inhibition with codlemone was observed from nonactive compounds. In field trapping, F(10,11)-codlemone and Cl-codlemone were more attractive to male codling moths than codlemone itself. Possible explanations of this activity are discussed.     

Gelatin/pectin-based film incorporated with essential oils: Functional characteristics and shelf life extension of tilapia fillets under refrigeration

Fish gelatin-pectin (Gel_Ext/Pec) composite films incorporated with Mentha pulegium essential oil (MEO) and Lavandula angustifolia essential oil (LEO) at two concentrations (0.5% and 1.5%) were developed and their physicochemical, mechanical, and antimicrobial properties were determined. Gel_Ext/Pec-based film incorporated with 1.5% MEO (Gel_Ext/Pec + 1.5% MEO) showed the highest antimicrobial activity against all bacterial strains tested. Incorporation of essential oils decreased significantly the tensile strength of all the films investigated. The film showing the best functional and antimicrobial properties (Gel_ext/Pec + 1.5% MEO) was used to prolong the shelf life of tilapia fillets under refrigeration. Control (unwrapped) and wrapped fillets were analyzed every 3 days in terms of microbiological (total viable count (TVC), psychrotrophic bacteria count (PC), lactic acid bacteria (LAB) and Enterobacteriaceae (ENT), and physicochemical parameters (total volatile base nitrogen [TVB-N] and pH). Gel_ext/Pec + 1.5% MEO antimicrobial film retarded significantly (p < .05) the growth of TVC, LAB, PC, and ENT, throughout 12 days of storage compared with the control. Gel_ext/Pec + 1.5% MEO could be considered as an effective packaging to maintain the quality and extend the shelf life of tilapia fillets under refrigeration.