Over the past decade, reckless usage of synthetic pesticides and fertilizers in agriculture has made the environment and human health progressively vulnerable. This setting leads to the pursuit of other environmentally friendly interventions. Amongst the suggested solutions, the use of chitin and chitosan came about, whether alone or in combination with endophytic bacterial strains. In the framework of this research, we reported an assortment of studies on the physico-chemical properties and potential applications in the agricultural field of two biopolymers extracted from shrimp shells (chitin and chitosan), in addition to their uses as biofertilizers and biostimulators in combination with bacterial strains of the genus Bacillus sp. (having biochemical and enzymatic properties).

Humans consume snail flesh as part of their diet. To assess its nutritional value and toxicity, chemical analyses were conducted to confirm the presence of protein, total and reduced carbohydrates, fat, fatty acid composition and mineral components. Furthermore, an acute toxicity study was carried out to determine the safety of Helix aspersa Müller snail flesh. H. aspersa Müller snail flesh exhibits a high nutritional content, a good ω3/ω6 ratio and higher levels of unsaturated fatty acids. Various minerals have been found in the flesh of H. aspersa Müller. Around 76.91 kcal, or 3.84% of the energy of a daily meal of 2000 kcal, are present in 100 g of this flesh. The evaluation of the antioxidant capacity indicated that the flesh’s extracts contained a large quantity of antioxidant biomolecules. Administration of the aqueous extract of H. aspersa Müller flesh didn’t cause death in laboratory rats, indicating that the lethal dose 50 is greater than 2000 mg·kg⁻¹ body weight. The consumption of the flesh of H. aspersa Müller is highly recommended for human consumption due to its high concentration of nutrients and essential elements, as well as unsaturated fats, and due to its safety.

The study of dyscalculia requires an analysis of the current developed hypotheses which describe the cognitive mechanisms involved in this neurodevelopmental disorder. The objective of our review is to determine any progress in modeling developmental dyscalculia. The first hypothesis suggests that dyscalculia is the consequence of a specific deficit level number on the precise number system and the approximate system. Then, the second hypothesis states that developmental dyscalculia is linked to a failure to process non-symbolic representations of numbers. On the other hand, the third suggests that dyscalculia is caused by a lack of access to numerical quantities from symbols. However, the last hypothesis asserts that developmental dyscalculia is linked to general deficits. All these hypotheses are compatible with recent neuroimaging results and raise new horizons for experimentation, which will allow the development of precise diagnostic tools and the improvement of intervention strategies and the remediation of developmental dyscalculia.

The present work reports the synthesis of pure hydroxyapatite and HAp supported Ag3PO4 (Ag3PO4/HAp composites) with varying amounts of silver ions Ag+ with a facile in-situ ion exchange method. XRD results of Ag3PO4/HAp composite reveal the peaks characteristic of pure HAp with additional peaks of silver ions which suggest the deposit of silver particles on the support surface (HAp). The nano-composites Ag3PO4/HAp samples show good adsorption and improved photocatalytic activities in methylene blue MB degradation (more than 70%). Antibacterial study of Ag3PO4/HAp nano-composites showed that the HAp dried at 90°C possesses some antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. Also, compared to HAp sample, deposition of Ag3PO4 nanoparticles on HAp surface improves the antibacterial performance of the composites.

Background: Chitin and chitosan are natural products extracted from shrimp shells. They are non-toxic, biocompatible and biodegradable which favors many applications in agricultural domain. Moreover, chitin and chitosan are known as stimulators of photosynthetic rates and enhance pants growth through minerals contains (C, O, N ….). In the present study, these co-products are evaluated for their ability to stimulate the germination and growth of Lycopersicon esculentum L., Capsicum annuum L. and Solanum melongena L. Methods: The experiments were conducted at Ibn Tofail University-Kenitra, between July 2016 to January 2018. The experiments are carried out by using a germination test for the three seeds. On the other hand, the in vivo test is used to determine the effect of the biopolymers on plant growth (length, fresh and dry weights of aerial and root parts, number and weight of the obtained fruits). Result: In vitro studies reveal a promoter action of chitosan and the mixture chitin-chitosan on increasing seed germination percentage by 16%, 34% and 22%. Thus, at both 25, 50 and 100 mg/l of chitin or chitosan, increase vigor index, shoot length and root is obtained. In vivo, the effect of chitin and chitosan is limited to stimulation of the lengths, fresh and dry weights of plants. However, a highly significant increase in the number and weight of the fruits is marked by the weekly soil amendment by the chitin-chitosan mixture at 25 mg/l and 100 mg/l.