Development and characterization of bionanocomposites based on poly(3‐hydroxybutyrate) and cellulose nanocrystals for packaging applications

Poly(3‐hydroxybutyrate) (PHB)‐based bionanocomposites were prepared using various percentages of cellulose nanocrystals (CNCs) by a solution casting method. CNCs were prepared from microcrystalline cellulose using sulfuric acid hydrolysis. The influence of CNCs on PHB properties was evaluated using differential scanning calorimetry, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetry and tensile testing. Vapor permeation and light transmission of the materials were also measured. Differential scanning calorimetric tests demonstrated that CNCs were effective PHB nucleation agents. Tensile strength and Young's modulus of PHB increased with increasing CNC concentration. Moreover, the PHB/CNC bionanocomposites exhibited reduced water vapor permeation compared to neat PHB and had better UV barrier properties than commodity polymers such as polypropylene. It was found that nanocomposites with 6 wt% of CNCs had the optimum balance among thermal, mechanical and barrier properties. © 2016 Society of Chemical Industry     

Inhibition of copper corrosion in chloride solutions by heterocyclic compounds

Following a research programme on copper corrosion inhibition in neutral aqueous solutions, the present paper deals with the results obtained with some heterocyclic organic compounds as copper corrosion inhibitors in 0.1 NaCl solutions. The results are compared with those obtained with 1,2,3-benzotriazole and 2-benzothiazolethiol. The inhibiting action of the compounds mentioned has been determined by measuring corrosion rates and by tracing polarization curves. The characteristics of the surface layers have been investigated by recording the photopotentials by a pulse technique. The oscillographic recording of the sign, amplitude and time-constant of the photopotentials has been obtained on electrodes in free corrosion conditions and during anodic and cathodic polarization. These measurements allow the determination of the semiconducting properties of the surface layers. Attentative is made to correlate the photopotentials data with the inhibiting efficiency of the compounds studied.     

JIDE: a new software for computer-aided design of hip prosthesis

This work is aimed at developing an innovative simulation environment supporting and improving the design of standard joint implants (JPD integrated design environment (JIDE)). The conceptual workflow starts from the design of a new implant, by using conventional CAD programmes and completes with the generation of a report that summarises the goodness for a new implant against a database of human bone anatomies. For each dataset in the database, the JPD application calculates a set of quantitative indicators that will support the designer in the evaluation of its design on a statistical basis. The resulting system is thus directed to prostheses manufacturers and addresses a market segment that appears to have a steady growth in the future.     

Diesel particulate traps regenerated by catalytic combustion

The development of catalytic means for the regeneration of particulate-laden traps for diesel exhaust cleaning is the main topic of this paper. All the steps of the catalytic trap preparation are dealt with, including: the synthesis and choice of the proper catalyst and trap materials, the development ofin situ catalyst deposition, and the bench testing of the derived catalytic traps. Two different traps were considered (i.e., silicon carbide and cordierite wallflow monoliths operating via a shallow-bed filtration mechanism), whereas the best catalyst selected was the perovskite LaCr_0.9O₃. The filtration efficiency and the pressure drops of the catalytic and non-catalytic monoliths were evaluated on a diesel engine bench under various operating conditions. On the basis of the obtained results the catalysed SiC converter was found to be the most satisfactory converter to be placed on the exhaust line of the modern common rail diesel-engine cars.     

Monogenic Autoinflammatory Diseases: State of the Art and Future Perspectives

Systemic autoinflammatory diseases are a heterogeneous family of disorders characterized by a dysregulation of the innate immune system, in which sterile inflammation primarily develops through antigen-independent hyperactivation of immune pathways. In most cases, they have a strong genetic background, with mutations in single genes involved in inflammation. Therefore, they can derive from different pathogenic mechanisms at any level, such as dysregulated inflammasome-mediated production of cytokines, intracellular stress, defective regulatory pathways, altered protein folding, enhanced NF-kappaB signalling, ubiquitination disorders, interferon pathway upregulation and complement activation. Since the discover of pathogenic mutations of the pyrin-encoding gene MEFV in Familial Mediterranean Fever, more than 50 monogenic autoinflammatory diseases have been discovered thanks to the advances in genetic sequencing: the advent of new genetic analysis techniques and the discovery of genes involved in autoinflammatory diseases have allowed a better understanding of the underlying innate immunologic pathways and pathogenetic mechanisms, thus opening new perspectives in targeted therapies. Moreover, this field of research has become of great interest, since more than a hundred clinical trials for autoinflammatory diseases are currently active or recently concluded, allowing us to hope for considerable acquisitions for the next few years. General paediatricians need to be aware of the importance of this group of diseases and they should consider autoinflammatory diseases in patients with clinical hallmarks, in order to guide further examinations and refer the patient to a specialist rheumatologist. Here we resume the pathogenesis, clinical aspects and diagnosis of the most important autoinflammatory diseases in children.     

Separating stress and time dependent effects in the temperature dependent creep of polyethylene nanocomposites

The nonlinear time dependent creep of linear‐low density polyethylene (LLDPE) reinforced with montmorillonite layered silicate was investigated. A previous study related the time/stress dependence of creep compliance of the material at room temperature using the Burger and Kohlrausch‐Williams‐Watts models. Using both the creep and recovery compliance curves, we employ the Schapery formulation to study the relationship between deformation, time, stress, and temperature of LLDPE nanocomposites. Smooth mastercurves are constructed using time–temperature–stress superposition principles. The stress and temperature‐related creep constants and shift factors were determined for the material using the Schapery nonlinear viscoelastic equation. The prediction results confirm the enhanced creep resistance of nanofillers even at extended time scales and low temperatures. POLYM. ENG. SCI., 50:1646–1657, 2010. © 2010 Society of Plastics Engineers     

Effects of sociometric testing on children's behavior and loneliness in school.

Examined the effects of a positive and negative peer nomination sociometric measure on children's (a) interactions with peers in general, (b) interactions with preferred and nonpreferred playmates, and (c) ratings of mood and of loneliness in school. Twenty-three 5th graders completed either a peer nomination sociometric or a control task (nominating preferred and nonpreferred school subjects). Before and after the nomination task, observers assessed the affective quality (positive, neutral, or negative) of subjects' peer interactions, and children completed mood and loneliness questionnaires. The procedures were subsequently replicated by administering the sociometric task to the control subjects. Analyses revealed no differences between the peer and control nomination task groups on any of the dependent variables measured. Analyses of pre–post differences provided no evidence of negative effects, suggesting that the risk to elementary-school-age children of completing such a sociometric measure, provided certain procedural guidelines are followed, may be minimal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potential Effect of CD271 on Human Mesenchymal Stromal Cell Proliferation and Differentiation

The Low-Affinity Nerve Growth Factor Receptor (LNGFR), also known as CD271, is a member of the tumor necrosis factor receptor superfamily. The CD271 cell surface marker defines a subset of multipotential mesenchymal stromal cells and may be used to isolate and enrich cells derived from bone marrow aspirate. In this study, we compare the proliferative and differentiation potentials of CD271⁺ and CD271⁻ mesenchymal stromal cells. Mesenchymal stromal cells were isolated from bone marrow aspirate and adipose tissue by plastic adherence and positive selection. The proliferation and differentiation potentials of CD271⁺ and CD271⁻ mesenchymal stromal cells were assessed by inducing osteogenic, adipogenic and chondrogenic in vitro differentiation. Compared to CD271⁺, CD271⁻ mesenchymal stromal cells showed a lower proliferation rate and a decreased ability to give rise to osteocytes, adipocytes and chondrocytes. Furthermore, we observed that CD271⁺ mesenchymal stromal cells isolated from adipose tissue displayed a higher efficiency of proliferation and trilineage differentiation compared to CD271⁺ mesenchymal stromal cells isolated from bone marrow samples, although the CD271 expression levels were comparable. In conclusion, these data show that both the presence of CD271 antigen and the source of mesenchymal stromal cells represent important factors in determining the ability of the cells to proliferate and differentiate.     

Numerical simulation of soot filtration and combustion within diesel particulate filters

The numerous benefits offered by diesel engines, compared to gasoline ones, are balanced by a drawback of increasing concern, namely soot emissions. Nowadays, soot emissions can be reduced by physically trapping the particles within on-board diesel particulate filters (DPF). The filter gets progressively loaded by filtering the soot laden flue gases, thus causing an increasing pressure drop, until regeneration takes place. The aim of this work is to develop a fully predictive three-dimensional mathematical model able to accurately describe the soot deposition process into the filter, the consequent gradual modification of the properties of the filter itself (i.e. permeability and porosity), the formation of a soot filtration cake, and the final regeneration step. The commercial computational fluid dynamics (CFD) code Fluent 6.2.16, based on a finite-volume numerical scheme, is used to simulate the gas and particulate flow fields in the DPF, whereas particle filtration sub-models and regeneration kinetics are implemented through user-defined-subroutines (UDS).Model predictions highlight uneven soot deposition profiles in the first steps of the filtration process; however, the very high resistance to the gas flow of the readily formed cake layer determines the evolution into an almost constant layer of soot particles. The ignition of the loaded soot was simulated under different operating conditions, and two regeneration strategies were investigated: a “mild regeneration” at low temperature and oxygen concentration, that operated a spatially homogeneous ignition of the deposited soot, and a “fast regeneration”, with an uneven soot combustion along the axial coordinate of the filter, due to strong temperature gradients inside the filter itself. These findings are supported by comparison and validation with experimental data.