Novel biodegradable, biomimetic and functionalised polymer scaffolds to prevent expansion of post-infarct left ventricular remodelling

Over the past decade, a large number of strategies and technologies have been developed to reduce heart failure progression. Among these, cardiac tissue engineering is one of the most promising. Aim of this study is to develop a 3D scaffold to treat cardiac failure. A new three-block copolymer, obtained from δ-valerolactone and polyoxyethylene, was synthesised under high vacuum without catalyst. Copolymer/gelatine blends were microfabricated to obtain a ECM-like geometry. Structures were studied under morphological, mechanical, degradation and biological aspects. To prevent left ventricular remodelling, constructs were biofunctionalises with molecularly imprinted nanoparticles towards the matrix metalloproteinase MMP-9. Results showed that materials are able to reproduce the ECM structure with high resolution, mechanical properties were in the order of MPa similar to those of the native myocardium and cell viability was verified. Nanoparticles showed the capability to rebind MMP-9 (specific rebinding 18.67) and to be permanently immobilised on the scaffold surface.     

Co-designing for common values: creating hybrid spaces to nurture autonomous cooperation

ABSTRACT

The paper concerns the development of digitally-mediated technologies that value social cooperation as a common good rather than as a source of revenue and accumulation. The paper discusses the activities that shaped a European participatory design project which aims to develop a digital space that promotes and facilitates the ‘Commonfare’, a complementary approach to social welfare. The paper provides and discusses concrete examples of design artifacts to address a key question about the role of co- and participatory design in developing hybrid spaces that nurture sharing and autonomous cooperation: how can co-design practices promote alternatives to the commodification of digitally-mediated cooperation? The paper argues for a need to focus on relational, social, political and ethical values, and highlights the potential power of co- and participatory design processes to achieve this. In summary, the paper proposes that only by re-asserting the centrality of shared values and capacities, rather than individual needs or problems, co-design can reposition itself thereby encouraging autonomous cooperation.     

Different composition poly(methyl methacrylate-co-butyl methacrylate) copolymers through seeded semi-batch emulsion polymerization

In the present work the synthesis and the chemical and thermal characterization of poly(methyl methacrylate-co-butyl methacrylate) copolymer, in three different macromolecular compositions, are reported. The aim of the present work was the identification of a standard method to obtain copolymers with controlled macromolecular composition, molecular weights and particle size distribution, together with the identification of the effect of the macromolecular composition on the material properties. A monomer-starved seeded semi-batch emulsion reaction was carried out and optimized, monitoring the kinetic of the copolymerization through the evaluation of residual monomer amounts. Then, an evaluation of the macromolecular composition was performed by Fourier transform infrared spectroscopy analysis. Molecular weight, molecular weight distribution, latex characteristics and thermal behaviour were also investigated.     

Optimal Monetary Policy and Long-term Interest Rate Dynamics: Taylor Rule Extensions

Many proposals are made to extend Taylor rule by including in the optimal reaction function other variables than those originally introduced by Taylor (Discretion versus policy rules in practice, Carnegie-Rochester Conference Series on Public Policy, 1993). The empirical studies point out the importance of long-term interest rates to explain and to forecast the behaviour of the monetary policy control variable. In particular, the positive shocks on long-term interest rates seem to induce a restrictive monetary policy and this finding is explained through the hypothesis that these shocks include the rational expectations on the future inflation rate. McCallum (Federal Reserve of Richmond Economic Quarterly 91(4), 1–21, 2005) assumes a positive relation between long-term and short-term interest rates to explain the inconsistency of US data with the expectations theory of the interest rate term structure. In this paper a new theoretical model is developed and analysed where the model of Clarida et al. (Journal of Economic Literature, 37(4), 1661–1707, 1999) is extended in the above outline of the term structure rational expectations hypothesis and also the dynamics of the nominal long-term interest rate as well as the dynamics of real exchange rate are involved. The optimal reaction function is provided by the algorithm described in Dennis (Journal of Economic Dynamics & Control, 28, 1635–1660, 2005) and the empirical impulse response function is obtained by estimating a VAR model. In spite of the empirical finding, the results obtained from the proposed theoretical model show that the optimal response to a positive shock in long-term interest rate is a reduction in the short-term and an economic rationale of this finding is suggested.     

Evaluation of sustainability of a city through fuzzy logic

The sustainable indicators are characterized by a low degree of aggregation and a high amount of information. An indicator must show a synthetic representation of a real environmental, by using a value or a parameter, so that they can be easily used by policy makers. It is necessary to connect, therefore, the various systems in an appropriately integrated sustainable system. The indicators need to be aggregated based on the structure of the data. Each indicator must to be defined through a weight with reference to another weighted indicator.     

Severity of COVID-19 Patients Predicted by Serum Sphingolipids Signature

The reason behind the high inter-individual variability in response to SARS-CoV-2 infection and patient’s outcome is poorly understood. The present study targets the sphingolipid profile of twenty-four healthy controls and fifty-nine COVID-19 patients with different disease severity. Sera were analyzed by untargeted and targeted mass spectrometry and ELISA. Results indicated a progressive increase in dihydrosphingosine, dihydroceramides, ceramides, sphingosine, and a decrease in sphingosine-1-phosphate. These changes are associated with a serine palmitoyltransferase long chain base subunit 1 (SPTLC1) increase in relation to COVID-19 severity. Severe patients showed a decrease in sphingomyelins and a high level of acid sphingomyelinase (aSMase) that influences monosialodihexosyl ganglioside (GM3) C16:0 levels. Critical patients are characterized by high levels of dihydrosphingosine and dihydroceramide but not of glycosphingolipids. In severe and critical patients, unbalanced lipid metabolism induces lipid raft remodeling, leads to cell apoptosis and immunoescape, suggesting active sphingolipid participation in viral infection. Furthermore, results indicated that the sphingolipid and glycosphingolipid metabolic rewiring promoted by aSMase and GM3 is age-dependent but also characteristic of severe and critical patients influencing prognosis and increasing viral load. AUCs calculated from ROC curves indicated ceramides C16:0, C18:0, C24:1, sphingosine and SPTLC1 as putative biomarkers of disease evolution.     

Adhesion properties of poly(methylmethacrylate-co-n-butylmethacrylate) copolymers in stent coatings

This work explores the adhesion properties of polymer solutions and thin coatings obtained by different-composition poly(methylmethacrylate-co-n-butylmethacrylate) copolymers. Surface wettability, work of adhesion, and work of spreading are calculated for solutions. Increasing amounts of n-butylmethacrylate lead to higher values of work of adhesion, measured over two stent-like flat surfaces (AISI 316L and pyrolytic carbon). The same moiety induces the solution viscosity increase and the decrease of the work of spreading and allows obtaining more homogeneous coatings. Adhesion of thin coatings is tested in dry (cross-cut test) and wet (immersion) conditions. Adhesion tests of coatings obtained by solvent casting reflect thermodynamic parameters evaluated for solutions. Coatings show better strength in cross-cut tests and a prolonged adhesion in wet conditions by raising the n-butylmethacrylate fraction. The same trends are confirmed in commercial devices. In conclusion, the study of thermodynamic solution/substrate interactions can explain coating properties. The proposed approach is worthwhile to improve deposition procedures based on polymer solutions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47814.     

BDNF rs6265 Polymorphism and Its Methylation in Patients with Stroke Undergoing Rehabilitation

Brain-Derived Neurotrophic Factor (BDNF) and its rs6265 single nucleotide polymorphism (SNP) play an important role in post-stroke recovery. We investigated the correlation between BDNF rs6265 SNP and recovery outcome, measured by the modified Barthel index, in 49 patients with stroke hospitalized in our rehabilitation center at baseline (T0) and after 30 sessions of rehabilitation treatment (T1); moreover, we analyzed the methylation level of the CpG site created or abolished into BDNF rs6265 SNP. In total, 11 patients (22.4%) were heterozygous GA, and 32 (65.3%) and 6 (12.2%) patients were homozygous GG and AA, respectively. The univariate analysis showed a significant relationship between the BDNF rs6265 SNP and the modified Barthel index cut-off (χ²(1, N = 48) = 3.86, p = 0.049), considering patients divided for carrying (A+) or not carrying (A−) the A allele. A higher percentage of A− patients obtained a favorable outcome, as showed by the logistic regression model corrected by age and time since the stroke onset, compared with the A+ patients (OR: 5.59). At baseline (T0), the percentage of BDNF methylation was significantly different between GG (44.6 ± 1.1%), GA (39.5 ± 2.8%) and AA (28.5 ± 1.7%) alleles (p < 0.001). After rehabilitation (T1), only patients A− showed a significant increase in methylation percentages (mean change = 1.3, CI: 0.4–2.2, p = 0.007). This preliminary study deserves more investigation to confirm if BDNF rs6265 SNP and its methylation could be used as a biological marker of recovery in patients with stroke undergoing rehabilitation treatment.     

On the effect of macromolecular composition and drug loading on thermal and tensile mechanical properties of methyl methacrylate and butyl methacrylate copolymers

In the last years, drug-eluting stents (DES) were considered as an important biomedical technology for cardiovascular intervention. In these devices, a thin polymer coating covers the metallic structure, aiming at the release of one or more active principles with controlled delivery kinetics. During DES implantation, structural failures on the thin coating may occur because of the mechanical expansion of the structure. The presence of a drug in the polymer matrix could severely influence mechanical properties, thus a mechanical characterisation of polymers and drug-loaded matrices results fundamental. To characterise a material produced for the manufacturing of drug-loaded coatings for DES, in the present work the thermomechanical analysis of an acrylic copolymer loaded with a drug is proposed. Obtained results showed that macromolecular composition could be varied to obtain the desired mechanical compliance; in addition, the drug can act as plasticiser. The present study would underline that it is possible to control mechanical properties by synthesising a tailored copolymer; furthermore, the importance of the study of the final system is fundamental when a polymer is considered as potential candidate to obtain coatings for DES.