A new generation of bio-composite thermoplastic filaments for a more sustainable design of parts manufactured by FDM

The most recent developments of Fused Deposition Modelling (FDM) techniques are moving the application of Additive Manufacturing (AM) technologies toward new areas of investigation such as the biomedical, aerospace, and marine engineering in addition to the more consolidated industrial and civil fields. Some specific characteristics are required for the components designed for peculiar applications, such as complex geometries, lightweight, and high strength as well as breathability and aesthetic appearance specifically in the biomedical field. All these design specifications could be potentially satisfied by manufacturing with 3D printing techniques. Moreover, the development of purpose-dedicated filaments can be considered a key factor to successfully meet all the requirements. In this paper, fabrication and applications of five new thermoplastic materials with fillers are described and analyzed. They are organic bio-plastic compounds made of polylactic acid (PLA) and organic by-products. The growing interest in these new composite materials reinforced with organic by-products is due to the reduction of production management costs and their low environmental impact. In this study, the production workflow has been set up and described in detail. The main properties of these new thermoplastic materials have been analyzed with a major emphasis on strength, lightweight, and surface finish. The analysis showed that these materials can be particularly suitable for biomedical applications. Therefore, two different biomedical devices were selected and relative prototypes were manufactured with one of the analyzed thermoplastic materials. The feasibility, benefits, and performance of the thermoplastic material considered for these applications were successfully assessed

Self-Assembly of Discrete Porphyrin/Calix[4]tube Complexes Promoted by Potassium Ion Encapsulation

The pivotal role played by potassium ions in the noncovalent synthesis of discrete porphyrin-calixarene nanostructures has been examined. The flattened-cone conformation adopted by the two cavities of octa-cationic calix[4]tube C4T was found to prevent the formation of complexes with well-defined stoichiometry between this novel water-soluble calixarene and the tetra-anionic phenylsulfonate porphyrin CuTPPS. Conversely, preorganization of C4T into a C4v-symmetrical scaffold, triggered by potassium ion encapsulation (C4T@K+), allowed us to carry out an efficient hierarchical self-assembly process leading to 2D and 3D nanostructures. The stepwise formation of discrete CuTPPS/C4T@K+ noncovalent assemblies, containing up to 33 molecular elements, was conveniently monitored by UV/vis spectroscopy by following the absorbance of the porphyrin Soret band

La storia dell'arte come impegno civile per il territorio. In ricordo di Sergio Ortese (1971-2019)

Il libro, nata da una giornata di studi dedicata allo scomparso studioso Sergio Ortese (1971-2019), tenutasi nell'autunno 2019 presso il Monastero degli Olivetani di Lecce, raccoglie una serie di saggi che vanno dal Medioevo al contemporaneo prevalentemente dedicati a importanti casi storico-artistici del Salento e del Meridione tutt

Recognition and Sensing of Chiral Organic Molecules by Chiral Porphyrinoids: A Review

Porphyrinoids are extremely attractive for their electronic, optical, and coordination properties as well as for their versatile substitution at meso/β-positions. All these features allow porphyrinoids to behave as chiroptical hosts for chiral recognition by means of non-covalent interactions towards chiral guests. Over the years, chiral discrimination of chiral molecules such as amino acids, alcohols, amines, hydroxy-carboxylic acids, etc. has aroused the interest of the scientific community. Hence, this review aims to report on the progress to date by illustrating some relevant research regarding the chiral recognition of a multitude of chiral organic guests through several chiral mono- and bis-porphyrins via different spectroscopic techniques

Alzheimer's Disease Costs: What We Know and What We Should Take into Account

Abstract Background/Objective: Alzheimer's disease (AD) is a very costly pathology. Total costs of AD result from the sum of direct and indirect costs. Intangible costs represent an additional burden that is difficult to quantify. This paper has reviewed the evaluation of the costs of AD and the methodologies to estimate them, and proposes the use of some tools which may be useful in establishing the financial weight of the disease. Method: A systematic literature search was conducted using the Pubmed and Medline databases as a source of published papers. Results: In AD, direct and indirect costs and their sum (total costs) are very high and tend to increase parallel with the evolution of the pathology. The evolution of AD is characterized by the loss of functional autonomy, the onset of behavioral and sleep disorders, and the development of delusions and hallucinations. This requires more frequent medical examinations and hospitalizations resulting in higher direct costs, which become the relevant weight. None of the papers reviewed investigated intangible cost. Conclusion: The calculation of costs of AD is frequently based on cognitive decline and the degree of dependence of patients. The evaluation of intangible costs (psychological pain of the patient and of the unpaid caregivers' and their impaired quality of life) is a missing aspect in all reviewed studies. Due to the complexity of AD, it will be necessary to adopt cost evaluation systems including the different dimensions of the problem and its various aspects

Chiral Recognition of L- and D- Amino Acid by Porphyrin Supramolecular Aggregates

We report of the interactions between four amino acids lysine (Lys), arginine (Arg), histidine (His), and phenylalanine (Phe) with the J-aggregates of the protonated 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin H4TPPS. Several aspects of these self-assembled systems have been analyzed: (i) the chiral transfer process; (ii) the hierarchical effects leading to the aggregates formation; and, (iii) the influence of the amino acid concentrations on both transferring and storing chiral information. We have demonstrated that the efficient control on the J-aggregates chirality is obtained when all amino acids are tested and that the chirality transfer process is under hierarchical control. Finally, the chiral porphyrin aggregates obtained exhibit strong chiral inertia

Porphyrin/sPEEK Membranes with Improved Conductivity and Durability for PEFC Technology

Advanced composite membranes have been obtained by incorporation of the mesa-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) into a sulfonated poly(etheretherketone) (sPEEK). The presence of porphyrins in their monomeric, dimeric, and aggregated forms into the membrane ionic domains have been investigated by static and time-resolved spectroscopic techniques. In particular, we succeeded in modulating the percentage of the different porphyrin species present into the proton-conducting channels acting on the dye load in the range 0.35-5 wt % porphyrin/polymer. The nanostructure of all the composite membranes has been investigated by small-angle X-ray scattering. This latter shows how the presence of TPPS porphyrins into the membrane ionic domains induces a reorganization of polymer chains in a more stable and organized lamellar-like structure with respect to the pristine polymeric matrix. Finally, the composite membranes have been used as proton exchange membrane for fuel cells (PEFCs) technology. The presence of porphyrins improved the performance of the membranes in terms of proton conductivity and stability. In particular, the 0.77 wt % composite membrane has been tested in a PEFC single cell simulating the operative conditions typical for portable applications, highlighting an improved stability compared to that of the sPEEK pristine membranes

Polyethersulfone Mats Functionalized with Porphyrin for Removal of Para-nitroaniline from Aqueous Solution

The dispersion of para-nitroaniline (p-NA) in water poses a threat to the environment and human health. Therefore, the development of functional adsorbents to remove this harmful compound is crucial to the implementation of wastewater purification strategies, and electrospun mats represent a versatile and cost-effective class of materials that are useful for this application. In the present study, we tested the ability of some polyethersulfone (PES) nanofibers containing adsorbed porphyrin molecules to remove p-NA from water. The functional mats in this study were obtained by two different approaches based on fiber impregnation or doping. In particular, meso-tetraphenyl porphyrin (H2TPP) or zinc(II) meso-tetraphenyl porphyrin (ZnTPP) were immobilized on the surface of PES fiber mats by dip-coating or added to the PES electrospun solution to obtain porphyrin-doped PES mats. The presence of porphyrins on the fiber surfaces was confirmed by UV–Vis spectroscopy, fluorescence measurements, and XPS analysis. p-NA removal from water solutions was spectrophotometrically detected and evaluated

Self-Assembly of Discrete Porphyrin/Calix[4]tube Complexes Promoted by Potassium Ion Encapsulation

The pivotal role played by potassium ions in the noncovalent synthesis of discrete porphyrin-calixarene nanostructures has been examined. The flattened-cone conformation adopted by the two cavities of octa-cationic calix[4]tube C4T was found to prevent the formation of complexes with well-defined stoichiometry between this novel water-soluble calixarene and the tetra-anionic phenylsulfonate porphyrin CuTPPS. Conversely, preorganization of C4T into a C4v-symmetrical scaffold, triggered by potassium ion encapsulation (C4T@K+), allowed us to carry out an efficient hierarchical self-assembly process leading to 2D and 3D nanostructures. The stepwise formation of discrete CuTPPS/C4T@K+ noncovalent assemblies, containing up to 33 molecular elements, was conveniently monitored by UV/vis spectroscopy by following the absorbance of the porphyrin Soret band

Porphyrin/sPEEK Membranes with Improved Conductivity and Durability for PEFC Technology

Advanced composite membranes have been obtained by incorporation of the <i>meso</i>-tetrakis­(4-sulfonatophenyl)­porphyrin (TPPS) into a sulfonated poly­(etheretherketone) (sPEEK). The presence of porphyrins in their monomeric, dimeric, and aggregated forms into the membrane ionic domains have been investigated by static and time-resolved spectroscopic techniques. In particular, we succeeded in modulating the percentage of the different porphyrin species present into the proton-conducting channels acting on the dye load in the range 0.35–5 wt % porphyrin/polymer. The nanostructure of all the composite membranes has been investigated by small-angle X-ray scattering. This latter shows how the presence of TPPS porphyrins into the membrane ionic domains induces a reorganization of polymer chains in a more stable and organized lamellar-like structure with respect to the pristine polymeric matrix. Finally, the composite membranes have been used as proton exchange membrane for fuel cells (PEFCs) technology. The presence of porphyrins improved the performance of the membranes in terms of proton conductivity and stability. In particular, the 0.77 wt % composite membrane has been tested in a PEFC single cell simulating the operative conditions typical for portable applications, highlighting an improved stability compared to that of the sPEEK pristine membranes