Characterization Techniques for Hydroxyapatite Deposited by Plasma Spray on Hip Prosthesis

As part of a characterization research on hydroxyapatite (HAp) plasma deposits for hip prosthesis, crystallinity and residual stresses weredetemiined at the interface Hap'TA6V. A traditional method employed by several laboratories is based on X-ray diffraction by a powder mixture of the investigated HAp sample with a standard of crystallinity Al₂O₃ Four new methods were investigated for determining the crystallinity of HAp sample, two of which are based on x-ray diffraction, one on neutron diffraction and one on the infrared absorption spectrometry. Whereas the three techniques require the use of powders, the neutron technique can be applied also to the intact HAp deposits. All four methods provide reasonable results, not very different one from each other, with a greater accuracy than for the x-ray and IR methods.     

Polystyrene recycling processes by dissolution in ethyl acetate

This study evaluated the thermal, morphological, chemical, and mechanical properties of virgin and recycled polystyrene. The recycling process was carried out by dissolution of polystyrene (extruded and crystal) in ethyl acetate, followed by two processes for solvent removal: vaporization by direct contact with water at 85 °C in a tubular evaporator and vaporization during the extrusion process. For the samples produced by solvent evaporation in the tubular evaporator, there was practically no degradation on polymer chain, neither reduction in glass transition temperature. For the samples produced by solvent evaporation during the extrusion, a polymer chain degradation was noted by reduction in molar weight and in glass transition temperature. The FTIR evaluation suggests that polymer oxidative degradation, in both samples, was more pronounced in the extruded sample. The removal of plasticizing additives could be evidenced by the glass transition temperature increase in the recycled samples produced in the tubular evaporator. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46208.     

Surface functionalization by smart coatings: Stimuli-responsive binary polymer brushes

Heterogeneous binary polymer brushes consist of an assembly of polymer chains of two incompatible polymers that are attached by one end to the surface with sufficient grafting density. They have been investigated experimentally only for a short time. Those brushes can be used in the form of ultrathin polymeric layers as a versatile tool for surface engineering to tune physico-chemical surface characteristics as wettability, surface charge, chemical composition or morphology, and furthermore to create switchable and responsive surface properties. For the fabrication of these layers “grafting-from” (as radical polymerization at the interface) and “grafting-to” (as tethering of the polymer chains from solution) methods were developed and investigated in detail.     

Introducing semantic variables in mixed distance measures: Impact on hierarchical clustering

Today, it is well known that taking into account the semantic information available for categorical variables sensibly improves the meaningfulness of the final results of any analysis. The paper presents a generalization of mixed Gibert’s metrics, which originally handled numerical and categorical variables, to include also semantic variables. Semantic variables are defined as categorical variables related to a reference ontology (ontologies are formal structures to model semantic relationships between the concepts of a certain domain). The superconcept-based distance (SCD) is introduced to compare semantic variables taking into account the information provided by the reference ontology. A benchmark shows the good performance of SCD with respect to other proposals, taken from the literature, to compare semantic features. Mixed Gibert’s metrics is generalized incorporating SCD. Finally, two real applications based on touristic data show the impact of the generalized Gibert’s metrics in clustering procedures and, in consequence, the impact of taking into account the reference ontology in clustering. The main conclusion is that the reference ontology, when available, can sensibly improve the meaningfulness of the final clusters.     

Semantic similarity estimation from multiple ontologies

The estimation of semantic similarity between words is an important task in many language related applications. In the past, several approaches to assess similarity by evaluating the knowledge modelled in an ontology have been proposed. However, in many domains, knowledge is dispersed through several partial and/or overlapping ontologies. Because most previous works on semantic similarity only support a unique input ontology, we propose a method to enable similarity estimation across multiple ontologies. Our method identifies different cases according to which ontology/ies input terms belong. We propose several heuristics to deal with each case, aiming to solve missing values, when partial knowledge is available, and to capture the strongest semantic evidence that results in the most accurate similarity assessment, when dealing with overlapping knowledge. We evaluate and compare our method using several general purpose and biomedical benchmarks of word pairs whose similarity has been assessed by human experts, and several general purpose (WordNet) and biomedical ontologies (SNOMED CT and MeSH). Results show that our method is able to improve the accuracy of similarity estimation in comparison to single ontology approaches and against state of the art related works in multi-ontology similarity assessment.     

Application of products of reaction between melamine and glycidol as substrates for oligoetherols and polyurethane foams containing 1,3,5‐triazine rings

Hydroxyalkyl derivatives of melamine were obtained by addition of melamine to glycidol. These derivatives were then used to obtain multifunctional oligoetherols by reaction with oxiranes and alkylene carbonates. The structure and properties of the oligoetherols were studied in detail. The oligoetherols were then used to obtain polyurethane foams of enhanced thermal stability. The foams showed marked thermal resistance at 200 °C. The beneficial feature of the obtained foams was their increased compression strength after thermal exposure. © 2013 Society of Chemical Industry     

Knowledge-driven delivery of home care services

Home Care (HC) assistance is emerging as an effective and efficient alternative to institutionalized care, especially for the case of senior patients that present multiple co-morbidities and require life long treatments under continuous supervision. The care of such patients requires the definition of specially tailored treatments and their delivery involves the coordination of a team of professionals from different institutions, requiring the management of many kinds of knowledge (medical, organizational, social and procedural). The K4Care project aims to assist the HC of elderly patients by proposing a standard HC model and implementing it in a knowledge-driven e-health platform aimed to support the provision of HC services. This paper focuses on two knowledge-based personalization aspects incorporated in the platform that aim to overcome the difficulties of HC delivery. The first one is the assistance to medical practitioners in the process of defining a customized treatment adjusted to the medical and social conditions of a particular patient in order to consider multiple co-morbidities. The second one is the possibility of tailoring the profiles of the care professionals according to the medical and organizational daily requirements in order to allow a flexible care delivery. Those two aspects, guided by the knowledge explicitly represented in the platform, play a crucial role in the medical and social acceptance of this kind of e-health systems. The paper also includes a real case study designed and tested by healthcare professionals and includes encouraging results from the test of the platform in a real health care environment in the city of Pollenza (Italy).     

Influence of additives on interfacial phenomena during film formation of powder coatings

Film formation of powder coatings is illuminated from a physico-chemical point of view. Significant parameters influencing the film formation of powder coatings are surface (wetting) tension and viscosity of the polymer melt formed during the film formation process. A newly developed measuring device for the investigation of wetting at elevated temperatures is presented. This device allows systematic investigations of the temperature dependence of the wetting tension of powder coating binder systems. By combining analytical and surface tension measurements, it is possible to gain new information about the mechanism of action of additives in these melts. Hohe Stra?e 6, D-01069 Dresden, Germany.