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

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

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

A longitudinal study of brain atrophy and cognitive disturbances in the early phase of relapsing-remitting multiple sclerosis

Objective—(a) To establish whether the cognitive decline of the early phase of relapsing-remitting multiple sclerosis depends on the progression of the burden of disease, or on the loss of brain parenchyma, or is influenced by both; (b) to monitor the loss of brain parenchyma in the early phase of the disease; and (c) to examine its possible relation with the progression of physical disability. Methods—For 2 years 53 patients with clinically definite relapsing-remitting multiple sclerosis with disease duration 1–5 years and expanded disability status scale<5.0 at baseline were monitored.The neuropsychological performances, the psychological functioning, the neurological impairment, and the disability have beenassessedatbaselineandafter2years. Patients also underwent PD/T2 and T1 weighted brain MRI.T2 and T1 lesion volumes were measured by a semiautomatic technique. Quantification of brain parenchymal volumes was obtained using a highly reproducible computerised interactive program. The relation between cognitive impairment and MRI findings has been investigated by partial correlation and stepwise multiple regression analyses excluding the eVects of age, education, anxiety, depression, and total days of steroid use. Results—In the 2 years of the study the meanchangeforT2andT1lesionvolumes and brain parenchymal volumes were +1.7 ml (95% confidence interval (95% CI) 1.3– 2.2, p=0.005, (29.8%); +0.2 ml, 95% CI 0.15–0.26, p=0.004, (25%); and –32.3 ml, 95% CI 24.2–42.3, p<0.0001, (2.7%), respectively. Overall, 14 patients (26.4%) were judged to be cognitively impaired at baseline and 28 (52.8%) at the end of the follow up. Of the 18 neuropsychological tests and subtests employed in the study, patients with multiple sclerosis failed 5.8 (SD 2.3) tests at the baseline and 8.4 (SD 2.9) (p<0.0001) tests at the end of the study. When the cognitive changes were examined in individual patients, five (9.4%) of them were considered cognitively improved, 33 (62.3%) remained stable, and 15 (28.3%) worsened over 2 years. T2 and T1 volume changes in improved, stable, and worsened patients did not show any significant diVerence, whereas brain parenchymal volume decrease in cognitively worsened patients was significantly greater (−66 ml (5.4%), 95% CI 37–108.9, p=0.0031). The cognitive impairment was independently predicted over 2 years only by the change of brain parenchymal volumes (R=0.51, p=0.0003). Ten patients (18.9%), who worsened by one or more points in the EDSS during the follow up period had significant decreases in brain parenchymal volumes (−99 ml (8%),95% CI 47.6–182.3,p=0.005). At the end of the study the loss of brain parenchyma correlated significantly with change in EDSS (r= 0.59, p<0.0001). Conclusions—In the early phase of relapsing-remitting multiple sclerosis the cognitive deterioration relies more on the development of brain parenchymal volume atrophy than on the extent of burden of disease in the brain. The loss of brain parenchymal volume underlies the progressive accumulation of physical disability from the initial phase of the disease, which becomes more demonstrable only if studied with longer observation periods. Probably, the main pathological substrate of brain atrophy in the early stage of the disease is early axonal loss, which causes the progression of neurological deficits and the development of cognitive impairment. These data support the debated opinion that disease modifying therapy should be initiated as early as possible

Non-Motor and Motor Features in LRRK2 Transgenic Mice

10.1371/journal.pone.0070249PLoS ONE87-POLN

A systematic review of catechol-o-methyltransferase inhibitors: efficacy and safety in clinical practice.

Catechol-O-methyltransferase (COMT) inhibitors are drugs commonly used in the management of patients with Parkinson disease complicated by motor fluctuations. Among them, entacapone is the most commonly used. Tolcapone has been reintroduced in patients where entacapone has proved to be ineffective after being withdrawn from the market because of sporadic cases of hepatotoxicity. The last COMT inhibitor is nebicapone, which use in clinical practice is still under study. OBJECTIVES: The objectives of this study were to analyze the clinical efficacy in reducing motor complications and to evaluate their use in clinical practice and the adverse events reported in the literature. METHODS: Scientific articles of the main previously mentioned drugs have been reviewed. RESULTS: All these 3 drugs have proved to be effective in improving wearing-off and significantly reduce the daily dose of levodopa at the number of daily intakes. Tolcapone is undoubtedly the most effective drug, although in clinical practice sporadic cases of hepatotoxicity have limited its use in patients unresponsive to entacapone. Nebicapone is effective, and its safety is still under evaluation. Entacapone is generally well tolerated, and no significant adverse events are reported. CONCLUSIONS: To manage motor fluctuations, the use of COMT inhibitors is now consolidated in the common clinical practice. Tolcapone is used as a second choice in patients with severe motor fluctuations not responsive to entacapone

Un insolito caso clinico di atrofia olivo-ponto-cerebellare associata a paraganglioma giugulare.

Atrofia olivo-ponto cerebellare associato alla presenza di paragangliom

Myelin protein zero Val102fs mutation manifesting with isolated spinal root hypertrophy.

The Val102fs mutation of the myelin protein zero gene (MPZ) has been associated with Charcot\u2013Marie\u2013Tooth disease type 1B (CMT1B). Here we describe an unusual presentation of the Val102fs mutation characterized by symptoms of spinal root hypertrophy with no overt peroneal muscular atrophy. Two sisters aged 41 and 35 years complained of neck pain and presented only pes cavus or deep-tendon hyporeflexia. In both of them magnetic resonance imaging revealed non-enhancing hypertrophy of spinal roots misdiagnosed as neurofibromatosis; neurophysiology disclosed a demyelinating neuropathy and addressed the correct molecular diagnosis. This report adds new data concerning the clinical presentations of MPZ mutations