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Modeling the 2D Van der Waals (vdW) heterostructure photocatalysts is an effective way to take advantage of solar energy and suppressing the fast recombination rate of photo-generated charge carriers. In the present work, we have systematically investigated the electronic, optical and photocatalytic properties of the GaS/BTe vdW heterostructure under an applied external electric field using first-principles calculations. Our results reveal that the GaS/BTe vdW heterostructure has an indirect band gap of 1.06/1.59 eV with PBE/HSE06 functional without electric field. The results also imply that electrons are likely to transfer from GaS to BTe monolayer due to the deeper potential of BTe monolayer. The GaS/BTe vdW system forms a type-II band alignment and established a large electric field at the interface, controlling to effective separation of the electron–hole pairs. Also, the transverse external electric considerably changes the band gap and transform from type-II to type-I and type-III band alignments. The GaS/BTe vdW heterostructure, also enhanced the optical absorption as compared to pristine GaS and BTe monolayer. Furthermore, the ( − )ve electric field significantly increases the optical absorption spectrum in infrared (IR) to visible region, while the (+)ve electric field enhances the optical absorption coefficients in visible to ultraviolet (UV) region. The external transverse electric field enhances the hydrogen evolution reaction (HER) activity on the 2D vdW heterostructure. These obtained results predict that the 2D GaS/BTe vdW heterostructures carry potential applications to enhancing the photocatalytic performance under visible light irradiation.

Staphylococcus aureus is a major pathogen for humans who are causing infections of the skin, lungs and sepsis. These infections can be treated with appropriate antibiotics. Their selection is mainly based on culture and sensitivity. Moreover, the problem of antimicrobial resistance has grown around the world because of their irrational prescriptions. The judicious use of antibiotics will reduce the multidrug resistance to antibiotics and thereby improve patient management and reduce the morbidity and mortality. Therefore, the objective of this prospective study is to evaluate the sensitivity of Staphylococcus aureus strains that are isolated from different pathological products at Peltier hospital in Djibouti. This study aims to provide data on the selection of antibiotics which are suitable for the treatment of diseases caused by S. aureus., Journal of Analytical Sciences and Applied Biotechnology, مجلد 4, عدد 1 (2022): January - June

This study presents a new diet proposal for type 2 diabetics based on vegetables and fruits of the Cucurbitaceae family such as: cucumber, pickle, zucchini, squash, squash, watermelon and melon. The composition of these foods has a low carbohydrate content, this value which is considered acceptable for type 2 diabetics, also the foods used have very low lipid and protein values which characterizes the disadvantage of this diet, even if they contain acceptable levels of trace elements and vitamins. Sampling according to several criteria was carried out in order to obtain 7 patients out of 33 who participated in the proposal, and among them 3 participants who resisted following the diet for two months, after the 4 patients quit the diet following personal impediments. From a 9-week follow-up of the health status of the participants, the results show the effectiveness of the proposed diet based on the monitoring of fasting blood sugar and the percentages of glycated hemoglobin that decreased during the period of application of the model., Journal of Analytical Sciences and Applied Biotechnology, Vol 3, No 2 (2021): July - December (In progress)

Innovative adhesive formulations have been developed in the laboratory based on urea-formaldehyde resin by adding medicinal plants to an industrial adhesive formulation containing raw materials: urea-formaldehyde resin, urea, ammonium sulphate and starch. Specifically, Thymus species (Thymus bleicherianus, Thymus capitates, Thymus satureioides, Thymus vulgaris and Thymus zygis) replaced part of the starch and were considered as the second filler in the formulations. The physico-chemical properties of the resulting adhesive formulations, such as: pH, viscosity, gel time, solids content, density, concentration of free formaldehyde and color were measured, and characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FTIR). In order to evaluate the mechanical performances of adhesive formulations based on plants, plywood panels were produced and their mechanical properties were studied. These mechanical properties included the shear strength, bending strength and the modulus of elasticity. The performance of these panels is comparable to that of plywood panels made using the standard adhesive formulation. From the results obtained, and following the statistical studies, the new adhesive formulations based on plants have the same physico-chemical properties, the same morphologies, and the same mechanical properties. Moreover, the novel adhesives are more viscous, and they have less free formaldehyde content than the commercial formulation.

Ocimum plants are of great interest to traditional medicine in the history of several civilizations, particularly in terms of chronic human diseases. Essential oils obtained from this genus have also been used as therapeutic agents. In this present work, two plants of the Ocimum species from Djibouti, Ocimum basilicum L. and Ocimum americanum L., were subjected to hydrodistillation to obtain their essential oils. Gas chromatography-mass spectrometry was performed to determine the chemical composition of both essential oils. Linalool (41.2%) and estragole (30.1%) are the major compounds among the 37 compounds that have been identified in the essential oil of Ocimum basilicum L. (EOOB), and carvotanacetol (38.4%) and estragole (27.5%) are the main compounds among the 42 compounds that have been identified in the essential oil of Ocimum americanum L. (EOOA). Morever, the cytotoxic activity of EOs was evaluated against 13 human cancer cell lines (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC -5 and JIMT-T1) using a luminescence spectrophotometric method; hence, the oils showed significant cytotoxic activities. The antibacterial activities of the oils were assayed on five Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, Staphylococcus epidermidis and Corynebacterium sp.) and seven Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Shigella sonnei, Salmonella enterica sv. Typhimurium and Enterobacter cloacae) by agar disc diffusion methods. Both essential oils exhibited moderate activities against Streptococcus agalactiae, and thus each has an activity against Pseudomonas aeruginosa for EOOB and against Enterobacter cloacae for EOOA, while the others are negative. The findings of this work showed the promising anticancer effects of both oils against total cell lines with a potential for use as natural alternatives to synthetic drugs; however, there was only an antibacterial effect against Streptococcus agalactiae.

Aquatic ecosystems continue to be threatened and the impacts of anthropization on biodiversity and human health are unprecedented following untreated wastewater discharges. Our study consists of the analysis of organic pollution parameters (dissolved oxygen, forms of nitrogen, ortho phosphates, and COD) and microbiological indicators of faecal pollution of the waters of Oued El Khell. The latter receives municipal and domestic wastewater from the Ain Salma tourist complex that is poured directly onto the bed of Oued Bou-Iddar tributary of Oued el Kell that is use for the irrigation of vegetable crops. The results obtained show that the water from the study stations is classified as municipal wastewater after biological purification since the COD value varies between 80 and 100 mg / L. The Organic Pollution Index (OPI) shows the waters’ quality of stations sampled from a bacteriological point of view, the ratio (R: FC / FS) total coliforms (CF) and faecal streptococci (SF) show that the origin of faecal contamination is animal and human with a human predominance for S1 and S3 and human origin for station S2. According to Moroccan standards, the waters of the study are not suitable for irrigation and can affect human health.

The increase in the intensity of human and industrial activities has led to the contamination of agricultural soils with various pollutants. One of the major pollutants is the heavy metals (HMs), which are considered as abiotic stress factors, consequently altering the nutritional quality of food and increasing the risk of poisoning after ingestion of contaminated food with HMs. Our study aims to assess the effect of chromium VI (Cr VI) on maize cultivation. Our results show that Cr VI affected the biomass, yield (sheaths), chlorophyll and fat levels (automatically affects oil quality), generally chromium highly influenced the nutritional quality of Maize. On the other hand, we noted a slight increase in total soluble sugar (TSS) content and protein levels, this increase could be explained by the fact that in the presence of Cr VI in soil the plant has established defense mechanisms to protect itself against the damages caused by the Cr VI metal.

In the Mediterranean countries, olive waste, a co-product of the olive oil trituration process, presents a serious environmental problem because of their polyphenol charge, given the quantities rejected each year. In previous works, this waste has been co-composted with other substrates and has been transformed into non-phytotoxic substances in conformity with the French standard NFU44-051 due to their composition in nutritional elements like soluble sugars, proteins and mineral elements. This study examines the efficacy of these substances on radish and potato crops. To do this, seeds were sown on the plot. For each crop, 4 plots were planned: land amended with manure (M), NPK fertilizer (F), the vegetable water substance (VW) and the olive-pomace substance (OP) in addition to the vegetable water. The first three substances served as controls. A statistical study of correlation between the latter and those that characterize the soil after amendment was carried out. The obtained results showed that there are two strong correlations between pH, organic matter, dry matter and soil moisture amended by the OW compost and, on the one hand, the morphological growth parameters of the two crops and, on the other hand, the parameters of their production., Moroccan Journal of Chemistry, Vol. 10, No 3 (2022): in progress

In agriculture, the use of organic amendments allows a better sustainability and productivity of the crop by improving the quality and structure of the soil, due to their richness in organic matter and nutrients such as phosphorus, nitrogen, potassium, etc. This study aims to evaluate the effect of two composts of different compositions on the growth and yield of three types of trees: peach, pear and orange. The experimental design used is a randomized block with three replications. The treatment of trees was carried out by four types of amendments which were composts with olive waste (OW), olive mill wastewater (OMW), manure (M) and NPK fertilizer (F) of type 10-15-12. Their fertilizing power was evaluated by monitoring the morphological parameters of plant growth: height, trunk diameter, number of branches, and those of production including size, weight of fruit and yield. The obtained outcomes reveal that the two composts have a very highly significant effect on the investigated parameters. The production was recorded only in peach trees with a total yield of 31.5 t/ha; 25.5 t/ha; 22.5 t/ha; 18.5 t/ha, respectively for OW, OMW, F and M., Moroccan Journal of Chemistry, مجلد 10, عدد 2 (2022): in progress

The use of essential oils as bio-insecticides presents many previous world works particularly in Morocco. In addition, the present work is concerned with the measurement of the insecticidal activity of five essential oils: Cedrus atlantica, Citrus limonum, Rosmarinus officinalis, Syzygium aromaticum and Eucalyptus globulus, against insect pests of the flour (Tribolium confusum). After extraction by a Clevenger distiller of the five species, the chemical composition of the extracted essential oil was studied by gas chromatography coupled with mass spectrometry (GC-MS). The majority of the identified compounds of Cedrus atlantica are: α-himachalene 15.63%, β-himachalene 31.24% and γ-himachalene 14.46%. The major components of Citrus limonum are: Neral 13.60%,Neryl acetate 10.77% and α-Pinene 9.46 %. The majority compounds of Rosmarinus officinalis are: (-)-camphor31.16%, β-Caryophyllene 18.55% and 2,4-hexadiene, 3,4-dimethyl-, (Z, Z) 9.08%. The main Syzygium aromaticum compounds are: 1,1,4,8-tetramethyl-cis, cis, 4,7,10-cycloundecatriene 28.74%, Caryophyllene oxide 25.34% and Eugenol 18.63%. The main compounds of Eucalyptus globulus are: Estragole 28.14%, Terpinolene 7.12% and 1,4-Hexadiene, 5-methyl-3-(1-methylethylidene) 7.01%. The insecticidal properties of the oils studied give an interesting anti-appetizing effect. A preliminary study showed that these oils have a high toxicity towards this insect

Lavandula rejdalii Upson & Jury (L. rejdalii) is a Moroccan endemic plant, known for its medicinal and aromatic properties. However, little is known about its phytochemicals. In this work, L. rejda...

The rational design of anode materials plays a significant factor in harnessing energy storage. With an in‐depth insight into the relationships and mechanisms that underlie the charge and discharge process of two‐dimensional (2D) anode materials. The efficiency of rechargeable batteries has significantly been improved through the implementation of defect chemistry on anode materials. This mini review highlights the recent progress achieved in defect chemistry on 2D materials for advanced rechargeable battery electrodes, including vacancies, chemical functionalization, grain boundary, Stone Wales defects, holes and cracks, folding and wrinkling, layered von der Waals (vdW) heterostructure in 2D materials. The defect chemistry on 2D materials provides numerous features such as a more active adsorption sites, great adsorption energy, better ions‐diffusion and therefore higher ion storage, which enhances the efficiency of the battery electrode., Defect chemistry in 2D materials constitutes a major area of research in materials science leading to a new promising anode materials for metal‐ions batteries.

Solid-state systems serve as a candidate for clean energy applications driven by current technological demands. In this effort, density functional theory (DFT) has become a valuable asset to investigate the intrinsic electronic properties and holds a substantial promise for guiding the discovery of new materials. Herein, we have investigated the Li and Na decorated 2D boron phosphide (BP) monolayer as a potential candidate for hydrogen storage due to its lightweight and structural stability. Li and Na adatoms prefer to adsorb at the center of the hexagon with the binding energies 0.36 and 0.26 eV, respectively. The thermodynamic stabilities of BP monolayer in cases of 4Li@BP and 4Na@BP systems were evaluated at room temperature using ab initio molecular dynamics (AIMD) simulations. The study of the electronic structure revealed that the semiconducting BP sheets become metallic after the adatom adsorption. It was found that the dispersed Li and Na atoms on the monolayer surface significantly increase both the hydrogen binding energies and the hydrogen storage capacities. With one-sided coverage of Li and Na atoms, four H2 molecules were adsorbed with a gravimetric capacity of 4.917 and 4.558 wt%, respectively. For double-sided adatom coverage, a total of 16H2 molecules was captured around 4Li@BP and 4Na@BP complex with a gravimetric capacity of 7.402 and 6.446 wt%, respectively. These results suggest that boron phosphide (BP) can act as an effective substrate for H2 storage by carefully engineering it with metal decoration.

Hydrogen production via solar light-driven water dissociation has been regarded as an artificial and effective process to overcome the environmental problem as well as solving the current energy crisis. In this regard, numerous works have mainly been devoted to developing the appropriate photocatalyst which satisfies the conditions for water splitting and understanding the photocatalysis process. In this study, we propose for the first time the potential application of the two-dimensional Janus aluminum oxysulfide Al2OS as an efficient photocatalyst material for hydrogen-production H-2 through the first-principles calculations. Janus Al2OS monolayer has been designed from the parental binary aluminum sulfide AlS by substituting one sub-layer of sulfide atoms (S) to oxygen atoms (O). The electronic properties of the pristine AlS and the derived Janus Al2OS were computed using GGA-PBE and HSE06 functionals. According to the band structure, AlS monolayer shows a semiconductor behavior with an indirect bandgap of 2.14 eV whereas, the Janus Al2OS exhibits a direct bandgap of 1.579 eV. Motivated by the desirable bandgap of the Janus Al2OS, the absorption-coefficient of Janus Al2OS shows strong visible light harvesting compared to the parental AlS. Furthermore, the photocatalytic performance of Al2OS has been investigated. Our calculations demonstrate that the band edge position of Al2OS is suitable for the hydrogen evolution reaction (HER). More importantly, based on the reaction coordinate, it was found that the Gibbs free-energy Delta G(H*) of Al2OS is 0.97 eV which is smaller than of the two-dimensional Janus Ga2XY (X, Y = S, Se, Te with X not equal Y) reported recently. Moreover, this value decreases from 0.97 eV to 0.69 eV under 0.5 V/angstrom of an external electrical field. Our results indicate that Janus Al2OS fulfills the fundamental requirements for efficient photo-catalyst under visible light and provides new guidance for hydrogen-production via water splitting.

Promising flexible electrochemical energy storage systems (EESSs) are currently drawing considerable attention for their tremendous prospective end-use in portable self-powered electronic devices, including roll-up displays, and "smart "garments outfitted with piezoelectric patches to harvest energy from body movement. However, the lack of suitable battery electrodes that provides a specific electrochemical performance has made further development of these technologies challenging. Two-dimensional (2D) lightweight and flexible materials with outstanding physical and chemical properties, including mechanical strengths, hydrophilic surfaces, high surface metal diffusivity, and good conductivity, have been identified as a potential prospect for battery electrodes. In this study, taking a new 2D boron nitride allotrope, namely 2D orthorhombic diboron dinitride monolayer (o-B2N2) as representatives, we systematically explored several influencing factors, including electronic, mechanical, and their electrochemical properties (e.g., binding strength, ionic mobility, equilibrium voltage, and theoretical capacity). Considering potential charge-transfer polarization, we employed a charged electrode model to simulate ionic mobility and found ionic mobility has a unique dependence on the surface atomic configuration influenced by bond length, valence electron number, electrical conductivity, excellent ionic mobility, low equilibrium voltage with excellent stability, good flexibility, and extremely superior theoretical capacity, up to 8.7 times higher than that of widely commercialized graphite (3239.74 mAh g(-1) Vs 372 mAh g(-1)) in case of Li-ion batteries and 2159.83 mAh g(-1) in case of Na-ion batteries, indicating that the new predicted 2D o-B2N2 monolayer possess the capability to be ideal flexible anode materials for Lithium and Sodium-ion battery. Our finding provides valuable insights for experimental explorations of flexible anode candidates based on 2D o-B2N2 monolayer.

The production of biogas from food waste is a good approach to the minimization of food waste and increase in the production of renewable energy. However, the use of food waste as a feedstock for biogas production currently poses a difficulty due to an ineffective hydrolysis process, which is a pretreatment procedure and the initial step of the biogas conversion process. This restriction results from the food waste polymers’ solubilization and breakdown. This has an impact on the volume of biogas produced during the methanogenesis stage. It is essential to increase the biodegradation of organic compounds (OC) during the hydrolysis process to increase biogas generation. This study focuses on the enhancement of biogas production by the anaerobic digestion (AD) of food waste (FW). FW was hydrolyzed by the immobilized biofilm and digested anaerobically in a semi-continuous digester. Four different digesters including the control were prepared. The control digester composed of no hydrolyzed food waste had no immobilized biofilm while the other three digesters had immobilized biofilm-hydrolyzed food waste with inoculum concentrations of 10%, 30%, and 50%. The results showed that the 50% digester had the highest biogas yield of about 2000 mL/500 mL. The 10%, 30%, and control digesters had a biogas yield of 1523 mL, 753 mL, and 502 mL respectively. Thus, the analysis of total volatile solid (TVS) reduction in the digesters with 10%, 30%, and 50% inoculum and the control have increased to 43.4% for the digesters with 30% and 10%, 60% for the digester with 50% inoculum, and only 29% for the control. Total chemical demand (TCOD) removal increased to 29%, 33%, 43%, and 56% for the control, and 10%, 30%, and 50%, respectively for the inoculum-to-feed ratio. From these results, the 50% inoculum-to-feed ratio has shown the highest biogas production and highest degradation based on TVS reduction and TCOD reduction. Based on this study, the biofilm pretreatment method can be considered a promising method for the enhancement of biogas volume and biodegradation. Biogas production was high (2000 mL) for hydraulic retention time (HRT = 20) days but the HRT = 15 days was also able to produce a significant amount (1400 mL) of biogas and the 50% inoculum-to-feed ratio has shown the highest volume of biogas production.

The present study shows the opportunity of using biofilm in the hydrolysis step of food waste (FW) to increase biogas production. Therefore, screened biofilm-producing microorganisms were adopted to facilitate the biodegradation of organic compounds (OCs) and enhance the volume of biogas production. The biofilm-producing microorganisms were first immobilized on a granular activated carbon (GAC) surface, and the optimum values of immobilization time, mass of the GAC surface, and size of the microbial inoculums were found using the statistical methods of one-factor-at-a-time (OFAT) and the response surface methodology (RSM) using a face-centered central composite design (FCCCD). Based on the results, 48 h of incubation, 8 g of GAC, and 1 mL of inoculum were the optimum conditions when shaken at 37 °C and 150 rpm. Different biofilm amounts (328 mg, 492 mg, 656 mg, 820 mg, and 984 mg) were used in hydrolysis flasks operated in batch mode to increase the degradation of the OCs. The optimal level of the hydrolysis degradation was on day 3 and at 328 mg of biofilm; the total solid (TS) content was decreased from 115 gL−1 to 79 gL−1 (31%), and the TCOD was decreased from 85.33 gL−1 to 54.50 gL−1 (36%).

The natural cosmetics industry sector is a booming market globally. Recently, interest in the potential of microalgae in cosmetics stems from the fact that they present an emerging source of active ingredients. The work presented in this thesis is part of the promotion of Moroccan microalgae for cosmetic application, the objective of which is the development of new formulations based on the microalga Isochrysis galbana for the care and treatment of hair. After culturing the algal biomass in the laboratory, a series of biological activities were performed, hence the in vitro antibacterial activity against Cutibacterium acnes (ATCC 6919) and Staphylococcus epidermidis (ATCC14990) and another in vivo biological activity which is to control the growth of rabbit hair. All the experiments show results motivated to develop and formulate new cosmetic products based on microalgae extract for hair care., Journal of Analytical Sciences and Applied Biotechnology, Vol. 3, No 1 (2021): January - June (Call for papers)

This work proposes the studying of characterization analysis of two natural Moroccan clays (RC and GC) in the same location from Bejaad (Province of Khouribga, Morocco) and to know the relationship dependence between them. The values obtained during the determination of a few parameters (density, pH, conductivity, dry matter - moisture content, organic matter-mineral matter) show that the two materials RC and GC studied have the same physical-chemical properties. The all characterization of the two clays was carried out by XRD, XRF, FTIR, SEM/EDX and TGA. The results obtained show that the two materials have very irregular and microporous structures, a heterogeneity of the pore forms and they are contain a mixture of Kaolinite, Illite, Quartz, Calcite, and Dolomite, with the presence of Hematite only in clay RC. On the other hand, The statistical approach applied to determine the dependence relationship between the two clays was based on two tests: Student's t-test (Comparison of two means for physical-chemical parameters) and Pearson's test (contingency table for XRF analysis) in order to prove that the two materials studied are the same chemical and physical-chemical characteristics., Moroccan Journal of Chemistry, Vol 9, No 2 (2021): In Progress

EnvironmentAsia, 14, 1, 33-40