PbS/CdS/ZnS Quantum Dots: A Multifunctional Platform for In Vivo Near‐Infrared Low‐Dose Fluorescence Imaging

Over the past decade, near‐infrared (NIR)‐emitting nanoparticles have increasingly been investigated in biomedical research for use as fluorescent imaging probes. Here, high‐quality water‐dispersible core/shell/shell PbS/CdS/ZnS quantum dots (hereafter QDs) as NIR imaging probes fabricated through a rapid, cost‐effective microwave‐assisted cation exchange procedure are reported. These QDs have proven to be water dispersible, stable, and are expected to be nontoxic, resulting from the growth of an outer ZnS shell and the simultaneous surface functionalization with mercaptopropionic acid ligands. Care is taken to design the emission wavelength of the QDs probe lying within the second biological window (1000–1350 nm), which leads to higher penetration depths because of the low extinction coefficient of biological tissues in this spectral range. Furthermore, their intense fluorescence emission enables to follow the real‐time evolution of QD biodistribution among different organs of living mice, after low‐dose intravenous administration. In this paper, QD platform has proven to be capable (ex vivo and in vitro) of high‐resolution thermal sensing in the physiological temperature range. The investigation, together with the lack of noticeable toxicity from these PbS/CdS/ZnS QDs after preliminary studies, paves the way for their use as outstanding multifunctional probes both for in vitro and in vivo applications in biomedicine.     

Determination of the conformation of the human VDAC1 N-terminal peptide, a protein moiety essential for the functional properties of the pore

Mitochondrial porin or VDAC (voltage-dependent anion-selective channel) is the most abundant protein in the mitochondrial outer membrane. The structure of VDAC has been predicted to be a transmembrane beta-barrel with an alpha-helix at the N terminus. It is a matter of debate as to whether this putative alpha-helix plays a structural role as a component of the pore walls or a function in the pore activity. We have synthesised the human VDAC1 (HVDAC1) N-terminal peptide Ac-AVPPTYADLGKSARDVFTK-NH2 (Prn2-20) and determined its structure by CD and NMR spectroscopy. CD studies show that the Prn2-20 peptide exists in aqueous solvent as an unstructured peptide with no stable secondary structure. In membrane-mimetic SDS micelles or water/trifluoroethanol, however, it assumes an amphipathic alpha-helix conformation between Tyr5 and Val16, as deduced from NMR. No ordered structure was observed in dodecyl beta-maltoside. Differential scanning calorimetric measurements were carried out in order to examine the membrane affinity of the peptide. Upon interaction with the negatively charged 1,2 dipalmitoyl-sn-glycero-3-phosphoserine membrane, Prn2-20 exhibited distinctive behaviour, suggesting that electrostatics play an important role. Interaction between the peptide and artificial bilayers indicates that the peptide lies on the membrane surface. Recombinant HVDAC1 deletion mutants, devoid of seven or 19 N-terminal amino acids, were used for transfection of eukaryotic cells. Over-expression of HVDAC1 increases the number of Cos cells with depolarised mitochondria, and this effect is progressively reduced in cells transfected with HVDAC1 lacking those seven or 19 amino acids. The mitochondrial targeting of the deletion mutants is unaffected. The overall picture emerging from our experiments is that the VDAC N-terminal peptide plays a role in the proper function of this protein during apoptotic events.     

Development of smooth finishes in electrostatic fluidized bed (EFB) coating process of high-performance thermoplastic powders (PPA 571 H)

This paper deals with the analysis of the evolution of the surface morphology of metal substrates coated with high-performance thermoplastic powders, namely PPA 571 H, by using electrostatic fluidized bed (EFB) process. Attention has been particularly focused on the relationship between baking time and temperature of EFB coated substrates and the morphological characteristics of the resulting polymeric films.

First, thermal behaviour of PPA 571 H polymeric powders was characterized by using standard calorimetric techniques. Accordingly, PPA 571 H melting kinetic was experimentally deduced. Based upon experimental findings, predictive analytical model was also developed and employed to trace ‘iso-conversion’ curves out.

Second, metal substrates, made from low carbon steel (AISI 1040), were EFB coated and baked at several baking time and temperatures. Combined analyses of scanning electron and confocal microscopes were led to measure the evolution of the films surface morphology under different baking conditions. Accordingly, a relationship between film morphologies and melting degree was sought. Consistent trends of roughness parameters versus baking parameters were found, with smoother finishes of the polymeric films being achieved for higher degrees of melting, that is, for higher baking temperature and time. Full maps and related analytical models of the finishing levels according to baking parameters were also built up, hence providing first useful indications to powder coaters on how to best deal with their settings.     

Silk Materials – A Road to Sustainable High Technology

This review addresses the use of silk protein as a sustainable material in optics and photonics, electronics and optoelectronic applications. These options represent additional developments for this technology platform that compound the broad utility and impact of this material for medical needs that have been recently described in the literature. The favorable properties of the material certainly make a favorable case for the use of silk, yet serve as a broad inspiration to further develop biological foundries for both the synthesis and processing of Nature's materials for technological applications.     

An unmanned aerial vehicle-based system for large scale metrology applications

Different manufacturing environments, such as aerospace, automotive, shipbuilding, and railway, reveal their interest in large scale metrology (LSM) instruments, to provide support in assembly, alignment, inspection, and robot tracking tasks. Notwithstanding different levels of portability, the overall measurement procedure actually involves a direct interaction between the measuring equipment and the operator, as well as a strong dependence on human skills. This paper presents a novel metrological system, scaling down this interaction to a mission management task and aimed at making system performance uniform. The proposed architecture entrusts an unmanned aerial vehicle (UAV) with the task of carrying the sensor equipment and of moving the measuring probe. The design process of the proposed system is detailed and faced with a two-level approach. The first level is directed to identify the available start-up technology, its limitations and sensitivity to the design parameters, while the second level is focused on the experimental testing of a preliminary test-bed to investigate the overall system performance. An actual implementation of the proposed architecture is herein discussed, focusing on system feasibility and presenting some preliminary experimental results.     

The effect of database dirty data on h-index calculation

As all databases, the bibliometric ones (e.g. Scopus, Web of Knowledge and Google Scholar) are not exempt from errors, such as missing or wrong records, which may obviously affect publication/citation statistics and—more in general—the resulting bibliometric indicators. This paper tries to answer to the question “What is the effect of database uncertainty on the evaluation of the h-index?”, breaking the paradigm of deterministic database analysis and treating responses to database queries as random variables. Precisely an informetric model of the h-index is used to quantify the variability of this indicator with respect to the variability stemming from errors in database records. Some preliminary results are presented and discussed.     

Morphology and degradation properties of PCL/HYAFF11® composite scaffolds with multi-scale degradation rate

The analysis of scaffold degradation is a promising strategy for understanding the dynamic changes in texture and pore morphology which accompany polymer resorption, and for collecting same fundamental indicators regarding the potential fate of the scaffold in the biological environment. In this study, we investigate the morphology and degradation properties of three composite scaffolds based on poly(ε-caprolactone) (PCL) embedded with benzyl ester of hyaluronic acid (HYAFF11®) phases, and, in turn, different reinforcement systems – i.e., calcium phosphate particles or continuous poly(lactic acid) (PLA) fibres. Scanning electron microscopy (SEM) and μ-tomography supported by digital image analysis enabled a not invasive investigation of the scaffold morphology, providing a quantitative assessment of porosity (which ranged from 63.1 to 82.8), pore sizes (which varied from 170.5 to 230.4 μm) and pore interconnectivity. Thermal analyses (DSC and TGA) and Raman spectroscopy demonstrated the multi-scale degradation of the composite with highly tailoring degradation kinetics depending on the component material phases and scaffold architecture changes, due to their conditioning in simulated in vivo environment (i.e., SBF solution). These results demonstrate that the judicious mixing of materials with faster (i.e., HYAFF11) and slower (i.e., PLA and PCL) degradation kinetics, different size and shape (i.e., domains, particles or long fibres), certainly concurs to design a smart composite scaffold with time-controlled degradation which can support the regeneration of a large variety of tissues, from the cartilage to the bone.