Bionanocomposites based on a covalent network of chitosan and edge functionalized graphene layers

Graphene has outstanding thermal, mechanical and electronic properties. Bionanocomposites are an emerging class of materials, designed with the aim of achieving advanced structural and functional properties by using biobased polymers. As biopolymer, a great interest is for chitosan (CS), poly (N-acetyl-D-glucosamine), a copolymer of linked 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose. Graphene and graphene related materials are increasingly used for the preparation of bionanocomposites. In this study, a high surface area graphite was edge functionalized with hydroxyl groups (G-OH) through the reaction with KOH. G-CHO, with 4.5 mmol/g of functional group, was prepared from G-OH by means of the Reimer-Tieman reaction. Carbon papers and aerogels were prepared from chitosan and graphene layers with aldehydic edge functional groups (G-CHO) able to form chemical bonds with chitosan and thus to form a crosslinked network. Characterization of the graphitic materials was performed with elemental analysis, titration, X-ray analysis and Raman spectroscopy. CS and G-CHO were mixed with mortar and pestle and carbon papers and aerogels were obtained from a stable acidic water suspension through casting and liophilization, respectively. This work demonstrates that carbon papers and aerogels can be prepared without adopting the traditional oxidation-reduction procedure, avoiding harsh reaction conditions, dangerous and toxic reagents, solvents and catalysts and paves the way for selective modification of graphene layers, exploiting the reactivity of aromatic rings

Sepiolite with enhanced chemical reactivity as filler for rubber compounds

Reinforcing fillers are essential ingredients of rubber composites and, among them, inorganic oxides/hydroxides play a crucial role. Silica, with adequate coupling agents, is the best filler for tyre compounds with low energy dissipation and fuel consumption [1]. In recent years, interest has been increasing for biosourced fillers. Sepiolite is one of the most studied, thanks to its nanometric size and high aspect ratio [1-2]. However, sepiolite can hardly behave as a reinforcing filler, without establishing a chemical interaction with the rubber matrix. It is possible to pursue such objective by using an efficient coupling agent. In this study, sepiolite was functionalized with a pyrrole derivative, (2,5-dimethyl-1-(3-(triethoxysilyl) propyl)-1H-pyrrole) (APTESP), by simply mixing in water and heating, performing first evaporation and then the functionalization reaction. The Sepiolite/APTESP adduct was used as reinforcing filler in NR based composites, as the only filler or in a hybrid filler system with carbon black. The composites were prepared via melt blending in internal mixers. Sulfur based crosslinking was carried out and characterization was performed by means of dynamic-mechanical and tensile tests. Results The adduct Sepiolite/APTESP was successfully prepared, by using water as the reaction medium. The amount of APTESP was between 5 and 10% and the functionalization yield was higher than 70%. Sepiolite promoted the dynamic-mechanical reinforcement of the rubber composites, thanks to APTESP as coupling agent. The mechanical percolation threshold in sepiolite, as the only filler in NR, was observed at a sepiolite content of about 15 phr. When sepiolite/APTESP were used in place of CB, similar or lower values of hysteresis were obtained

The use of Genetic Algorithms to solve the allocation problems in the Life Cycle Assessment

The paper applies a GA (Genetic Algorithms) to a multi-output productive process of essential oils, natural and concen-trated juices from oranges and lemonsThe results obtained for the case study taken into consideration showed that the application of GA allows to respect the energ y and mass balances for the examined system

Heterogeneity of neuroinflammatory responses in amyotrophic lateral sclerosis: A challenge or an opportunity?

Amyotrophic Lateral Sclerosis (ALS) is a complex pathology: (i) the neurodegeneration is chronic and progressive; it starts focally in specific central nervous system (CNS) areas and spreads to different districts; (ii) multiple cell types further than motor neurons (i.e., glial/immune system cells) are actively involved in the disease; (iii) both neurosupportive and neurotoxic neuroinflammatory responses were identified. Microglia cells (a key player of neuroinflammation in the CNS) attracted great interest as potential target cell population that could be modulated to counteract disease progression, at least in preclinical ALS models. However, the heterogeneous/multifaceted microglia cell responses occurring in different CNS districts during the disease represent a hurdle for clinical translation of single-drug therapies. To address this issue, over the past ten years, several studies attempted to dissect the complexity of microglia responses in ALS. In this review, we shall summarize these results highlighting how the heterogeneous signature displayed by ALS microglia reflects not only the extent of neuronal demise in different regions of the CNS, but also variable engagement in the attempts to cope with the neuronal damage. We shall discuss novel avenues opened by the advent of single-cell and spatial transcriptomics technologies, underlining the potential for discovery of novel therapeutic targets, as well as more specific diagnostic/prognostic not-invasive markers of neuroinflammation

Motor skills in children with primary headache: A pilot case-control study

Background: Headache is the most common painful manifestation in the developmental age, often accompanied by severe disability such as scholastic absenteeism, low quality of academic performance and compromised emotional functioning. The aim of the study is to evaluate praxic abilities in a population of children without aural migraine. Materials and methods: The test population consists of 10 subjects without migraine without aura (MwA), (8 Males) (mean age 8.40, SD ± 1.17) and 11 healthy children (7 Males) (mean age 8.27; SD ± 1.10; p = 0.800). All subjects underwent evaluation of motor coordination skills through the Battery for Children Movement Assessment (M-ABC). Results: The two groups (10 MwA vs 11 Controls) were similar for age (8.40 ± 1.17 vs 8.27 ± 1.10; p = 0.800), sex (p = 0.730), and BMI (p = 0.204). The migraine subjects show an average worse performance than the Movement ABC; specifically, migraineurs show significantly higher total score values (31.00 ± 23.65 vs 4.72 ± 2.61; p = 0.001), manual dexterity (12.10 ± 11.20 vs 2.04 ± 2.65; p = 0.009) and balance (14.85 ± 10.08 vs. 1.04 ± 1.05; p <0.001). The mean percentile of migraine performance is significantly reduced compared to controls (9.00 ± 3.82 vs 51.00 ± 24.34, p <0.001) (Table 1). Conclusion: Migraine can alter many cognitive and executive functions such as motor skills in developmental age

Bionanocomposites based on chitosan and few layers graphene. The effect of tailor-made functionalization

Bionanocomposites are an emerging class of material. They are designed and developed to achieve advanced structural and functional properties, by using biobased polymers. Among the bio-polymers, focus is on chitosan (CS), poly (N-acetyl-D-glucosamine), a copolymer of [1,4]-linked 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose. Research is steadily increasing on bionanocomposites with graphene and graphene related materials. It is here presented a research on bionanocomposites based on CS and graphene layers (G). Particular focus of the research was on the integration of the graphene layers in the nanocomposite. Materials were prepared based on the supramolecular interaction between CS and G. The core of the research was then on the edge functionalization of the layers. OH groups were added through the cycloaddition reaction with a biosourced pyrrole compound, serinol pyrrole (SP), carried out with the help of either thermal or mechanical energy, with an atom efficiency up to 96% and a very low E Factor. The preparation of CS/G adducts was very simple, even by using only mortar and pestle. OH groups were also added to the G edges by performing the reaction of G with KOH. The Reimer-Tiemann reaction on the G-OH adduct led to the introduction of aldehydic groups, which promote the crosslinking of CS. The CS/G adducts were characterized by means of wide angle X-ray diffraction, scanning and transmission electron microscopy, Fourier transform infrared, X-ray photoelectron and Raman spectroscopies. Thermal stability of the composites was studied by thermogravimetric analysis. Carbon papers and aerogels were prepared, studying the flexibility and the stability in various solvents in a wide pH range

Animals-assisted therapy: A brief review

In rehabilitative setting, the presence of animals can be considered as an important stimulus for verbal and social communication, and for mood regulation. Interaction with an animal is beneficial for children's development and numerous psychological tests have revealed that growing up with pets has a beneficial effect on children's self-esteem and self-confidence, can improve empathy, a sense of responsibility and cognitive development, as well as social status within the peer group

Neuropsychomotricity in water: A new rehabilitative tool for neruodevelop-mental disorders

Neuropsychomotricity in water is a rehabilitative practice that avails itself just of the liquid element, as a mediator of relationships: in water yes they upset all dynamics, be they relational, of equilibrium, of movement and perception, due to the fact that proprioceptive sensations, created by bodily contact with water, they are different than those generated by contact with air

Psychopathological and psychodynamic hypotheses for pediatric stuttering

Stuttering is a common language alteration in pediatric age consisting in repetitions and blocks, which entail a break in the rhythm and melody of the speech. According to the WHO it is a disorder of the rhythm of the word, the subject knows precisely what he would like to say, but at the same time he is not able to say it. It is a great inconvenience for those affected, also because the slowing down of speaking is not about thought or cognitive skills

Forensic considerations on violent parasomnias during lifespan

Nocturnal parasomnias are a group of sleep complex manifestation that don't alter the sleep macrostructure, but when persistent during adulthood may be assume violent aspects with relevant forensic implications about the guiltiness