Fatigue and healing properties of bituminous mastics reinforced with nano-sized additives

The research work described in the paper focused on fatigue and healing properties of bituminous mastics reinforced with nano-sized additives.Commercially available multiwall carbon nanotubes (CNTs) and montmorillonite nanoclay (NC) were combined with a single base bitumen and a standard mineral filler to produce bituminous mastics. These blends were prepared in the laboratory by making use of a technique consisting in simple shear mixing followed by sonication.Fatigue behaviour of mastics under repeated loading was investigated by means of time sweeps performed in the strain-controlled mode at various amplitudes. Healing potential was assessed by adopting a testing protocol specifically conceived to discriminate between recovery of damage induced by fatigue loading and other artefact phenomena which may affect material response. All rheological measurements were carried out with a dynamic shear rheometer in the parallel plates geometry.Outcomes of the experimental investigation were found to be highly dependent on the nature of additive type, as a result of the key role played by interaction mechanisms that nano-particles can establish within the bituminous mastic.     

Integrin-targeting with peptide-bioconjugated semiconductor-magnetic nanocrystalline heterostructures

Binary asymmetric nanocrystals (BNCs), composed of a photoactive TiO₂ nanorod joined with a superparamagnetic γ-Fe₂O₃ spherical domain, were embedded in polyethylene glycol modified phospholipid micelle and successfully bioconjugated to a suitably designed peptide containing an RGD motif. BNCs represent a relevant multifunctional nanomaterial, owing to the coexistence of two distinct domains in one particle, characterized by high photoactivity and magnetic properties, that is particularly suited for use as a phototherapy and hyperthermia agent as well as a magnetic probe in biological imaging. We selected the RGD motif in order to target integrin expressed on activated endothelial cells and several types of cancer cells. The prepared RGD-peptide/BNC conjugates, comprehensively monitored by using complementary optical and structural techniques, demonstrated a high stability and uniform dispersibility in biological media. The cytotoxicity of the RGD-peptide/BNC conjugates was studied in vitro. The cellular uptake of RGD-peptide conjugates in the cells, assessed by means of two distinct approaches, namely confocal microscopy analysis and emission spectroscopy determination in cell lysates, displayed selectivity of the RGD-peptide-BNC conjugate for the αvβ3 integrin. These RGD-peptide-BNC conjugates have a high potential for theranostic treatment of cancer.

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Influence of aggregate mineralogy on alkali–silica reaction studied by X-ray powder diffraction and imaging techniques

Reliable assessment of the potential alkali reactivity of aggregate to develop deleterious alkali–silica reaction is essential for construction of durable concrete structures. The potential alkali reactivity of silicified limestone and two limestones has been investigated. Preliminary characterisation of aggregate was performed by optical and environmental scanning electron microscopy. X-ray powder diffraction peak profile analysis was used to predict the aggregates’ potential alkali reactivity. Samples were aged in accordance to the RILEM AAR-2 procedure and further characterised by means of optical and environmental scanning electron microscopy as well as by synchrotron X-ray microtomography, where quantitative analysis relative to damage due to the alkali–silica reaction (ASR) was performed by morphometric analysis of volume data. Results highlight that (1) the microstructural domain size and microstrain values extracted form XRPD line profile analysis seem to be good parameters for predicting the potential alkali reactivity of quartz in aggregate, and (2) the mineralogy of the aggregate influences the weathering products (i.e. aggregate dissolution, ASR gel growth and microcracking) due to ASR in cement-based materials.     

Fast Computation of Exact G-Optimal Designs Via Iλ-Optimality

Exact G-optimal designs have rarely, if ever, been employed in practical applications. One reason for this is that, due to the computational difficulties involved, no statistical software system currently provides capabilities for constructing them. Two algorithms for exact G-optimal design construction of small designs involving one to three factors have been discussed in the literature: one employing a genetic algorithm and one employing a coordinate-exchange algorithm. However, these algorithms are extremely computer intensive in small experiments and do not scale beyond two or three factors. In this article, we develop a new method for constructing exact G-optimal designs using the integrated variance criterion, I_λ-optimality. We show that with careful selection of the weight function, a difficult exact G-optimal design construction problem can be converted to an equivalent exact I_λ-optimal design problem, which is easily and quickly solved. We illustrate the use of the algorithm for full quadratic models in one to five factors. The MATLAB codes used to implement our algorithm and the exact G-optimal designs produced by the algorithm for each test case are available online as supplementary material.     

Growth in Knowledge-Intensive Business Services: Evidence from Lombardy

This paper studies the growth patterns in knowledge-intensive business services (KIBS) in Lombardy on the basis of original firm-level survey data. The aim is to investigate in particular the role of and interplay between age and size of firms and the modes of innovation in the process of growth. Our findings indicate that younger firms tend to outperform incumbents for sales growth and that larger firms tend to grow more than smaller companies. However, the effects of firm size and age vary substantially according to the firm's specific pattern of innovation. In particular, highly innovative firms tend to outperform competitors regardless of their age or size, while for conservative KIBS, size is a prerequisite for growth. Investment in human capital and the service distribution network are important drivers of competition for growing KIBS.     

Toward High‐Dimensional Single‐Cell Analysis of Graphene Oxide Biological Impact: Tracking on Immune Cells by Single‐Cell Mass Cytometry

Considering the potential exposure to graphene, the most investigated nanomaterial, the assessment of the impact on human health has become an urgent need. The deep understanding of nanomaterial safety is today possible by high‐throughput single‐cell technologies. Single‐cell mass cytometry (cytometry by time‐of flight, CyTOF) shows an unparalleled ability to phenotypically and functionally profile complex cellular systems, in particular related to the immune system, as recently also proved for graphene impact. The next challenge is to track the graphene distribution at the single‐cell level. Therefore, graphene oxide (GO) is functionalized with AgInS₂ nanocrystals (GO–In), allowing to trace GO immune–cell interactions via the indium (¹¹⁵In) channel. Indium is specifically chosen to avoid overlaps with the commercial panels (>30 immune markers). As a proof of concept, the GO–In CyTOF tracking is performed at the single‐cell level on blood immune subpopulations, showing the GO interaction with monocytes and B cells, therefore guiding future immune studies. The proposed approach can be applied not only to the immune safety assessment of the multitude of graphene physical and chemical parameters, but also for graphene applications in neuroscience. Moreover, this approach can be translated to other 2D emerging materials and will likely advance the understanding of their toxicology.     

Dry coating of solid dosage forms: an overview of processes and applications

Dry coating techniques enable manufacturing of coated solid dosage forms with no, or very limited, use of solvents. As a result, major drawbacks associated with both organic solvents and aqueous coating systems can be overcome, such as toxicological, environmental, and safety-related issues on the one hand as well as costly drying phases and impaired product stability on the other. The considerable advantages related to solventless coating has been prompting a strong research interest in this field of pharmaceutics. In the article, processes and applications relevant to techniques intended for dry coating are analyzed and reviewed. Based on the physical state of the coat-forming agents, liquid- and solid-based techniques are distinguished. The former include hot-melt coating and coating by photocuring, while the latter encompass press coating and powder coating. Moreover, solventless techniques, such as injection molding and three-dimensional printing by fused deposition modeling, which are not purposely conceived for coating, are also discussed in that they would open new perspectives in the manufacturing of coated-like dosage forms.     

Modeled Microgravity Affects Fibroblast Functions Related to Wound Healing

Wound healing is crucial for the survival of an organism. Therefore, in the perspective of space exploration missions, it is important to understand if and how microgravity conditions affect the behavior of the cell populations involved in wound healing and the evolution of the process. Since fibroblasts are the major players in tissue repair, this study was focused on the behavior of fibroblasts in microgravity conditions, modeled by a RCCS. Cell cytoskeleton was studied by immunofluorescence microscopy, the ability to migrate was assessed by microchemotaxis and scratch assay, and the expression of markers of fibroblast activation, angiogenesis, and inflammation was assessed by western blot. Results revealed that after cell exposure to modeled microgravity conditions, a thorough rearrangement of microtubules occurred and α-SMA bundles were replaced by a tight network of faulty and disorganized filaments. Exposure to modeled microgravity induced a decrease in α-SMA and E-CAD expressions. Also, the expression of the pro-angiogenic protein VEGF decreased, while that of the inflammatory signal COX-2 increased. Fibroblast ability to adhere, migrate, and respond to chemoattractants (PRP), closely related to cytoskeleton integrity and membrane junctions, was significantly impaired. Nevertheless, PRP was able to partially restore fibroblast migration.