Hybrid cellulose–Basalt polypropylene composites with enhanced compatibility. The role of coupling agent

This study deals with the development and optimization of hybrid composites integrating microcrystalline cellulose and short basalt fibers in a polypropylene (PP) matrix to maximize the mechanical properties of resulting composites. To this aim, the effects of two different coupling agents, endowed with maleic anhydride (MA-g(grafted)-PP) and acrylic acid (AA-g-PP) functionalities, on the composite properties were investigated as a function of their amount. Tensile, flexural, impact and heat deflection temperature tests highlighted the lower reactivity and effectiveness of AA-g-PP, regardless of reinforcement type. Hybrid formulations with basalt/cellulose (15/15) and with 5 wt. % of MA-g-PP displayed remarkable increases in tensile strength and modulus, flexural strength and modulus, and notched Charpy impact strength, of 45% and 284%, 97% and 263%, and 13%, in comparison with neat PP, respectively. At the same time, the thermo-mechanical stability was enhanced by 65% compared to neat PP. The results of this study, if compared with the ones available in the literature, reveal the ability of such a combination of reinforcements to provide materials suitable for automotive applications with environmental benefits

Correlation between mechanical properties and processing conditions in rubber-toughened wood polymer composites

The use of wood fibers is a deeply investigated topic in current scientific research and one of their most common applications is as filler for thermoplastic polymers. The resulting material is a biocomposite, known as a Wood Polymer Composite (WPC). For increasing the sustainability and reducing the cost, it is convenient to increase the wood fiber content as much as possible, so that the polymeric fraction within the composite is thereby reduced. On the other hand, this is often thwarted by a sharp decrease in toughness and processability-a disadvantage that could be overcome by compounding the material with a toughening agent. This work deals with the mechanical properties in tension and impact of polypropylene filled with 50 wt.% wood flour, toughened with different amounts (0%, 10%, and 20%) of a polypropylene-based thermoplastic vulcanizate (TPV). Such properties are also investigated as a function of extrusion processing variables, such as the feeding mode (i.e., starve vs. flood feeding) and screw speed. It is found that the mechanical properties do depend on the processing conditions: the best properties are obtained either in starve feeding conditions, or in flood feeding conditions, but at a low screw speed. The toughening effect of TPV is significant when its content reaches 20 wt.%. For this percentage, the processing conditions are less relevant in governing the final properties of the composites in terms of the stiffness and strength

Dexamethasone downregulates autophagy through accelerated turn-over of the ulk-1 complex in a trabecular meshwork cells strain: Insights on steroid-induced glaucoma pathogenesis

Steroid-induced glaucoma is a severe pathological condition, sustained by a rapidly progressive increase in intraocular pressure (IOP), which is diagnosed in a subset of subjects who adhere to a glucocorticoid (GC)-based therapy. Molecular and clinical studies suggest that either natural or synthetic GCs induce a severe metabolic dysregulation of Trabecular Meshwork Cells (TMCs), an endothelial-derived histotype with phagocytic and secretive functions which lay at the iridocorneal angle in the anterior segment of the eye. Since TMCs physiologically regulate the composition and architecture of trabecular meshwork (TM), which is the main outflow pathway of aqueous humor, a fluid which shapes the eye globe and nourishes the lining cell types, GCs are supposed to trigger a pathological remodeling of the TM, inducing an IOP increase and retina mechanical compression. The metabolic dysregulation of TMCs induced by GCs exposure has never been characterized at the molecular detail. Herein, we report that, upon dexamethasone exposure, a TMCs strain develops a marked inhibition of the autophagosome biogenesis pathway through an enhanced turnover of two members of the Ulk-1 complex, the main platform for autophagy induction, through the Ubiquitin Proteasome System (UPS)

Surface modification of basalt fibres with ZnO nanorods and its effect on thermal and mechanical properties of pla-based composites

The composites based on basalt fibres and poly(lactic acid) (PLA) show promising applications in biomedical and automotive fields, but their mechanical performance is still largely hindered by poor interfacial properties. Zinc oxide nanorods have been successfully used to tune the PLA/basalt fibre interface by growing them on commercially available basalt fabrics. The hierarchical fibres significantly enhanced the mechanical properties of PLA-based composites, especially their flexural strength and stiffness. These values are 26% and 22% higher than those of unmodified basalt/PLA composites, and 24% and 34% higher than those of glass/PLA composites used as a baseline. The increase in tensile and flexural properties hinges on the mechanical interlocking action promoted by ZnO nanorods and on the creation of a compact transcrystallinity structure. A degradation of PLA matrix was detected but it was positively counteracted by the better interfacial stress transfer. This study offers a novel approach for modifying the fibre–matrix interface of biocomposites intended for high-performance applications

Functionalization of commercial electrospun veils with zinc oxide nanostructures

The present research is focused on the synthesis of hexagonal ZnO wurtzite nanorods for the decoration of commercially available electrospun nylon nanofibers. The growth of ZnO was performed by a hydrothermal technique and for the first time on commercial electrospun veils. The growth step was optimized by adopting a procedure with the refresh of growing solution each hour of treatment (Method 1) and with the maintenance of a specific growth solution volume for the entire duration of the treatment (Method 2). The overall treatment time and volume of solution were also optimized by analyzing the morphology of ZnO nanostructures, the coverage degree, the thermal and mechanical stability of the obtained decorated electrospun nanofibers. In the optimal synthesis conditions (Method 2), hexagonal ZnO nanorods with a diameter and length of 53.5 nm ± 5.7 nm and 375.4 nm ± 37.8 nm, respectively, were obtained with a homogeneous and complete coverage of the veils. This easily scalable procedure did not damage the veils that could be potentially used as toughening elements in composites to prevent delamination onset and propagation. The presence of photoreactive species makes these materials ideal also as environmentally friendly photocatalysts for wastewater treatment. In this regard, photocatalytic tests were performed using methylene blue (MB) as model compound. Under UV light irradiation, the degradation of MB followed a first kinetic order data fitting and after 3 h of treatment a MB degradation of 91.0% ± 5.1% was achieved. The reusability of decorated veils was evaluated and a decrease in photocatalysis efficiency was detected after the third cycle of use

Hypothalamo-pituitary axis and puberty

Puberty is a complex process that culminates in the acquisition of psychophysical maturity and reproductive capacity. This elaborate and fascinating process marks the end of childhood. Behind it lies a complex, genetically mediated neuroendocrine mechanism through which the gonads are activated thanks to the fine balance between central inhibitory and stimulating neuromodulators and hormones with both central and peripheral action. The onset of puberty involves the reactivation of the hypothalamic-pituitary-gonadal (HPG) axis, supported by the initial “kiss” between kisspeptin and the hypothalamic neurons that secrete GnRH (the GnRH “pulse generator”). This pulsatile production of GnRH is followed by a rise in LH and, consequently, in gonadal steroids. The onset of puberty varies naturally between individuals, and especially between males and females, in the latter of whom it is typically earlier. However, pathological variations, namely precocious and delayed puberty, are also possible. This article reviews the scientific literature on the physiological mechanisms of puberty and the main pathophysiological aspects of its onset

Disrupted Resting-State Functional Connectivity in Progressive Supranuclear Palsy

BACKGROUND AND PURPOSE: Studies on functional connectivity in progressive supranuclear palsy have been restricted to the thalamus and midbrain tegmentum. The present study aims to evaluate functional connectivity abnormalities of the subcortical structures in these patients. Functional connectivity will be correlated with motor and nonmotor symptoms of the disease. MATERIALS AND METHODS: Nineteen patients with progressive supranuclear palsy (mean age, 70.93 ± 5.19 years) and 12 age-matched healthy subjects (mean age, 69.17 ± 5.20 years) underwent multimodal MR imaging, including fMRI at rest, 3D T1-weighted imaging, and DTI. fMRI data were processed with fMRI of the Brain Software Library tools by using the dorsal midbrain tegmentum, thalamus, caudate nucleus, putamen, and pallidum as seed regions. RESULTS: Patients had lower functional connectivity than healthy subjects in all 5 resting-state networks, mainly involving the basal ganglia, thalamus, anterior cingulate, dorsolateral prefrontal and temporo-occipital cortices, supramarginal gyrus, supplementary motor area, and cerebellum. Compared with healthy subjects, patients also displayed subcortical atrophy and DTI abnormalities. Decreased thalamic functional connectivity correlated with clinical scores, as assessed by the Hoehn and Yahr Scale and by the bulbar and mentation subitems of the Progressive Supranuclear Palsy Rating Scale. Decreased pallidum functional connectivity correlated with lower Mini-Mental State Examination scores; decreased functional connectivity in the dorsal midbrain tegmentum network correlated with lower scores in the Frontal Assessment Battery. CONCLUSIONS: The present study demonstrates a widespread disruption of cortical-subcortical connectivity in progressive supranuclear palsy and provides further insight into the pathophysiologic mechanisms of motor and cognitive impairment in this condition

At the cutting edge against cancer: A perspective on immunoproteasome and immune checkpoints modulation as a potential therapeutic intervention

Simple Summary:& nbsp;Immunoproteasome plays a key role in the generation of antigenic peptides. Immune checkpoints therapy is a front-line treatment of advanced/metastatic tumors, and to improve its efficacy, a broader knowledge of the dynamics of antigen repertoire processing by cancer cells is mandatory. The scope of this review is to offer a picture of the role of immunoproteasome in antigen presentation to fuel the hypothesis of novel therapeutic interventions based on the modulation of this proteolytic complex and immune checkpoints.Immunoproteasome is a noncanonical form of proteasome with enzymological properties optimized for the generation of antigenic peptides presented in complex with class I MHC molecules. This enzymatic property makes the modulation of its activity a promising area of research. Nevertheless, immunotherapy has emerged as a front-line treatment of advanced/metastatic tumors providing outstanding improvement of life expectancy, even though not all patients achieve a long-lasting clinical benefit. To enhance the efficacy of the currently available immunotherapies and enable the development of new strategies, a broader knowledge of the dynamics of antigen repertoire processing by cancer cells is needed. Therefore, a better understanding of the role of immunoproteasome in antigen processing and of the therapeutic implication of its modulation is mandatory. Studies on the potential crosstalk between proteasome modulators and immune checkpoint inhibitors could provide novel perspectives and an unexplored treatment option for a variety of cancers

Disrupted Resting-State Functional Connectivity in Progressive Supranuclear Palsy

BACKGROUND AND PURPOSE: Studies on functional connectivity in progressive supranuclear palsy have been restricted to the thalamus and midbrain tegmentum. The present study aims to evaluate functional connectivity abnormalities of the subcortical structures in these patients. Functional connectivity will be correlated with motor and nonmotor symptoms of the disease. MATERIALS AND METHODS: Nineteen patients with progressive supranuclear palsy (mean age, 70.93 ± 5.19 years) and 12 age-matched healthy subjects (mean age, 69.17 ± 5.20 years) underwent multimodal MR imaging, including fMRI at rest, 3D T1-weighted imaging, and DTI. fMRI data were processed with fMRI of the Brain Software Library tools by using the dorsal midbrain tegmentum, thalamus, caudate nucleus, putamen, and pallidum as seed regions. RESULTS: Patients had lower functional connectivity than healthy subjects in all 5 resting-state networks, mainly involving the basal ganglia, thalamus, anterior cingulate, dorsolateral prefrontal and temporo-occipital cortices, supramarginal gyrus, supplementary motor area, and cerebellum. Compared with healthy subjects, patients also displayed subcortical atrophy and DTI abnormalities. Decreased thalamic functional connectivity correlated with clinical scores, as assessed by the Hoehn and Yahr Scale and by the bulbar and mentation subitems of the Progressive Supranuclear Palsy Rating Scale. Decreased pallidum functional connectivity correlated with lower Mini-Mental State Examination scores; decreased functional connectivity in the dorsal midbrain tegmentum network correlated with lower scores in the Frontal Assessment Battery. CONCLUSIONS: The present study demonstrates a widespread disruption of cortical-subcortical connectivity in progressive supranuclear palsy and provides further insight into the pathophysiologic mechanisms of motor and cognitive impairment in this condition