Two-step sinter-crystallization of K2O–CaO–P2O5–SiO2 (45S5-K) bioactive glass

Bioactive glasses and glass-ceramics (GCs) effectively regenerate bone tissue, however most GCs show improved mechanical properties. In this work, we developed and tested a rarely studied bioactive glass composition (24.4K₂O-26.9CaO-46.1SiO₂-2.6P₂O₅ mol%, identified as 45S5-K) with different particle sizes and heating rates to obtain a sintered GC that combines good fracture strength, low elastic modulus, and bioactivity. We analyzed the influence of the sintering processing conditions in the elastic modulus, Vickers microhardness, density, and crystal phase formation in the GC. The best GC shows improved properties compared with its parent glass. This glass achieves a good densification degree with a two-step viscous flow sintering approach and the resulting GC shows as high bioactivity as that of the standard 45S5 Bioglass®. Furthermore, the GC elastic modulus (56 GPa) is relatively low, minimizing stress shielding. Therefore, we unveiled the glass sintering behavior with concurrent crystallization of this complex bioactive glass composition and developed a potential GC for bone regeneration.     

XPS studies of directly fluorinated HDPE: problems and solutions

X-ray photoelectron spectroscopy (XPS) applied to the study of fluorinated polymer surfaces presents several problems related both to peak assignment and to degradation. In this work, we analyse extensively the question of XPS peak assignments in this kind of surfaces. We conclude that in this kind of surfaces using binding energy differences between fluorine and carbon is better than using absolute binding energies. Also a useful relation between fluorine photoelectron energy vs. polymer composition expressed through the atomic ratio fluorine/carbon (F/C) was found. A protocol for data treatment is proposed and applied to a XPS study of the degradation induced by X-ray on high-density polyethylene surfaces modified by direct fluorination. Results obtained for the degradation, namely the atomic ratio F/C obtained by two different methods, combined with angle resolved X-ray photoelectron spectroscopy (ARXPS) were used to study the fluorine concentration profile in depth, producing self-consistent results.     

A new family of sugar-inducible expression vectors for Escherichia coli

A set of 11 expression vectors was constructed, each of themharbouring a cloning cassette under the control of the promoter.Some of these vectors enable expression of foreign proteinsin the cytoplasm, while others include a synthetic sequencecoding for a very efficient secretion signal sequence. Otherfeatures are an fl origin of replication (in plus or minus orientation)and a promoter^up mutation that enhances the already very highlevel of expression from these vectors. With such a versatilevector family, cloning, sequencing and sitedirected mutagenesiscan be performed on the same vector, and the level of expressioncan be defined according to the specific constraints of a givenprotein.     

Assessment of Bonelike® graft with a resorbable matrix using an animal model

Synthetic bone grafts have been developed to provide an alternative to autografts and allografts. Bonelike® is a patented synthetic osteoconductive bone graft that mimics the mineral composition of natural bone. In the present preliminary animal studies a user-friendly version of synthetic bone graft Bonelike® have been developed by using a resorbable matrix, Floseal®, as a vehicle and raloxifene hydrochloride as a therapeutic molecule, that is known to decrease osteoclast activity and therefore enhanced bone formation. From histological and scanning electron microscopy evaluations, the use of Bonelike® associated with Floseal® and raloxifene hydrochloride showed that new bone was rapidly apposed on implanted granules and also that the presence of the matrix and therapeutic molecule does not alter the proven highly osteoconductivity properties of Bonelike®. Therefore, this association may be one step-forward for the clinical applications of Bonelike® scaffolds since it is much more easy-to-handle when compared to granular materials.     

Envelopes with microplastics generated from recycled plastic bags for crude oil sorption

Oil spill accidents in marine environments and the lack of disposal of post-consumer plastic are environmental problems worldwide. This study presents a sustainable alternative for both issues through envelopes filled with microplastics (MPs) from recycled bags for the sorption of spilled crude oil. Through particle size analysis by three different sieves (4, 9, and 20 mesh), different MP sizes were characterized by scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), density, contact angle (CA), and Fourier-transform infrared spectroscopy (FTIR). According to their sizes, the MPs were distributed in envelopes and submitted to crude oil sorption capacity and efficiency evaluation. Three MP particle sizes were obtained (from the largest to the smallest, according to the sieve mesh, MP4, MP9, and MP20). SEM images of samples exhibited irregular and porous surfaces, and MP4 had the smallest pore size (8.6 μm). BET showed that MP4 had the highest surface area (0.074 m²/g). The CA > 90° exposed that all samples were hydrophobic. FTIR spectrum demonstrated that the samples from the recycled bags were made of high density polyethylene (HDPE). The MP4 envelopes also had the best crude oil sorption results in capacity and efficiency (1.73 g/g and 68%, respectively), being a promising recycled sorbent in crude oil spillage applications.     

A strategy for allowing meaningful and comparable scores in approximate matching

Approximate data matching aims at assessing whether two distinct instances of data represent the same real-world object. The comparison between data values is usually done by applying a similarity function which returns a similarity score. If this score surpasses a given threshold, both data instances are considered as representing the same real-world object. These score values depend on the algorithm that implements the function and have no meaning to the user. In addition, score values generated by different functions are not comparable. This will potentially lead to problems when the scores returned by different similarity functions need to be combined for computing the similarity between records. In this article, we propose that thresholds should be defined in terms of the precision that is expected from the matching process rather than in terms of the raw scores returned by the similarity function. Precision is a widely known similarity metric and has a clear interpretation from the user's point of view. Our approach defines mappings from score values to precision values, which we call adjusted scores. In order to obtain such mappings, our approach requires training over a small dataset. Experiments show that training can be reused for different datasets on the same domain. Our results also demonstrate that existing methods for combining scores for computing the similarity between records may be enhanced if adjusted scores are used.     

Quantum Phase Transition in the BCS-to-BEC Evolution of p-wave Fermi Gases

We discuss the possibility of a quantum phase transition in ultra-cold spin-polarized Fermi gases which exhibit a p-wave Feshbach resonance. We show that when fermionic atoms form a condensate that can be externally tuned between the BCS and BEC limits, the zero temperature compressibility and the spin susceptibility of the fermionic gas are non-analytic functions of the two-body bound state energy. This non-analyticity is due to a massive rearrangement of the momentum distribution in the ground state of the system. Furthermore, we show that the low temperature superfluid density is also non-analytic and exhibits a dramatic change in behavior when the critical value of the bound state energy is crossed.     

From a Conceptual Framework for Agents and Objects to a Multi-Agent System Modeling Language

In this paper we propose a multi-agent system modeling language (MAS-ML) that extends UML (Unified Modeling Language) based on structural and dynamic properties presented in a conceptual framework (metamodel) called Taming Agents and Objects (TAO). Our focus is the adaptation according to TAO concepts of the static Class diagram and the interaction Sequence diagram proposed by UML. These two diagrams have been chosen because they are the most commonly used and because it is possible to use them to illustrate both the structural and dynamic aspects of TAO metamodel. We propose a conservative extension of the UML metamodel, which includes agent-related notions that are part of the TAO conceptual framework while preserving all object-related concepts, which constitute the UML metamodel. The main difference between our approach and the others presented in the literature is the clear definition and representation of the elements that compose MASs and their corresponding behavior. In order to extend UML with TAO non-object concepts, it is not possible to use only the three basic extensions mechanisms provided by UML and new metaclasses and stereotypes have been created and associated with the UML metamodel.     

Overview of the local production process of raw milk butter in Wallonia (Belgium)

This study aims to describe the procedures and practices used in local production of raw milk butter. The demand for local products is increasing; hence, there is a need to describe the practices used in the artisanal production of raw milk butter. Therefore, a survey of 147 raw milk butter producers was carried out. The results from the survey indicate that there is not one single way to produce butter at artisanal level. In terms of maturation, six temperature sequences were distinguished. Attention is required at every step of production starting from breeding.