Glass–ceramic scaffolds containing silica mesophases for bone grafting and drug delivery

Glass–ceramic macroporous scaffolds were prepared using glass powders and polyethylene (PE) particles of two different sizes. The starting glass, named as Fa-GC, belongs to the system SiO₂–P₂O₅–CaO–MgO–Na₂O–K₂O–CaF₂ and was synthesized by a traditional melting-quenching route. The glass was ground and sieved to obtain powders of specific size which were mixed with PE particles and then uniaxially pressed in order to obtain crack-free green samples. The compact of powders underwent a thermal treatment to remove the organic phase and to sinter the Fa-GC powders. Fa-GC scaffolds were characterized by means of X-Ray Diffraction, morphological observations, density measurements, image analysis, mechanical tests and in vitro tests. Composite systems were then prepared combining the drug uptake-delivery properties of MCM-41 silica micro/nanospheres with the Fa-GC scaffold. The system was prepared by soaking the scaffold into the MCM-41 synthesis batch. The composite scaffolds were characterized by means of X-Ray Diffraction, morphological observations, mechanical tests and in vitro tests. Ibuprofen was used as model drug for the uptake and delivery analysis of the composite system. In comparison with the MCM-41-free scaffold, both the adsorption capacity and the drug delivery behaviour were deeply affected by the presence of MCM-41 spheres inside the scaffold.     

Molecular Mechanisms and Biomarkers Associated with Chemotherapy-Induced AKI

Acute kidney injury (AKI) is a life-threatening condition characterized by a rapid and transient decrease in kidney function. AKI is part of an array of conditions collectively defined as acute kidney diseases (AKD). In AKD, persistent kidney damage and dysfunction lead to chronic kidney disease (CKD) over time. A variety of insults can trigger AKI; however, chemotherapy-associated nephrotoxicity is increasingly recognized as a significant side effect of chemotherapy. New biomarkers are urgently needed to identify patients at high risk of developing chemotherapy-associated nephrotoxicity and subsequent AKI. However, a lack of understanding of cellular mechanisms that trigger chemotherapy-related nephrotoxicity has hindered the identification of effective biomarkers to date. In this review, we aim to (1) describe the known and potential mechanisms related to chemotherapy-induced AKI; (2) summarize the available biomarkers for early AKI detection, and (3) raise awareness of chemotherapy-induced AKI.     

Return to Religion? Predictors of Religious Change among Baby-Boomers in their Transition to Later Life

In this paper, we investigated the correlates of change in religiosity among babyboomers as they aged from their 50s to their 60s. Change was assessed as a function of cognitive and behavioral manifestations of religious involvement, early religious participation, and challenges that emerged over this period of life. Using qualitative and quantitative data from 599 respondents in the 2016 wave of the Longitudinal Study of Generations, we examined retrospectively assessed religious change over the previous ten years and the precipitating reasons for such change. Religiosity was most likely to remain stable, but a significant minority of the sample became more religious over the past ten years; reasons included a shift away from worldly concerns, coping with loss and health problems, and intergenerational continuity. Structural equation modeling found that early exposure to religion strengthened religiosity through its association with both stronger cognitive and behavioral aspects of religious involvement. Losing of a partner, experiencing economic decline, and having health problems either increased or stabilized religiosity, complementing results from qualitative responses. In general, religious change, when it did occur, was in a positive direction and served as a resource for dealing with health and social losses. We anticipate this trend to intensify as baby-boomers advance to even later stages of the life-course.     

Fracture Strength of Plate and Tubular Forms of Monolithic Silicon Carbide Produced by Chemical Vapor Deposition

The fracture strength of silicon carbide (SiC) plate deposits produced by chemical vapor deposition (CVD) was determined from room temperature to 1500°C using a standard 4-point flexural test method (ASTM C1161). CVD SiC materials produced by two different manufacturers are shown to have only slightly different flexural strength values, which appear to result from differences in microstructure. Although CVD deposition of SiC results in a textured grain structure, the flexural strength was shown to be independent of the CVD growth direction. The orientation of machining marks was shown to have the most significant influence on flexural strength, as expected. The fracture strength of tubular forms of SiC produced by CVD deposition directly onto a mandrel was comparable to flexural bars machined from a plate deposit. The tubular (O-ring) specimens were much smaller in volume than the flexural bars, and higher strength values are predicted based on Weibull statistical theory for the O-ring specimens. Differences in microstructure between the plate deposits and deposits made on a mandrel result in different flaw distributions and comparable strength values for the flexural bar and O-ring specimens. These results indicate that compression testing of O-rings provides a more accurate strength measurement for tubular product forms of SiC due to more representative flaw distributions.     

SBA-15 ordered mesoporous silica inside a bioactive glass–ceramic scaffold for local drug delivery

The paper reports the synthesis of an ordered silica mesostructure of the SBA-15 type inside a macroporous bioactive glass-ceramic scaffold of the type SiO(2)-CaO-K(2)O, to combine the bioactivity of the latter with the release properties of the former, in view of local drug delivery from implants designed for tissue engineering. The standard procedure for SBA-15 synthesis has been modified to minimize the damage to the scaffold caused by the acidic synthesis medium. The composite system has been characterized by means of Scanning Electron Microscopy (coupled with EDS analysis), Small Angle X-Ray Diffraction, Thermogravimetry analysis and Infrared Spectroscopy: the formation of a well ordered hexagonal mesostructure was confirmed. Ibuprofen has been chosen as model drug. The uploading properties have been investigated of the scaffold-mesoporous silica composite as compared with the scaffold as such, and a five-fold increase in the adsorbing properties toward ibuprofen was found, due to the presence of the ordered mesoporous silica. The ibuprofen release to a SBF solution in vitro is complete in 1 day. Retention of bioactivity from the glass-ceramic scaffold after the silica mesostructure incorporation has been observed.     

Characterization of surface modified Ti-6Al-7Nb alloy

In the last years different types of surface modifications were developed with the aim of improving the osteointegration ability of titanium alloys. The chemical composition, crystallographic structure and morphology of a surface layer can be modified in order to obtain a better interaction between the implant, the cells and the organic fluids. The final goal is to obtain a more efficient bone growth also in critical clinical cases. In the present paper were reported several data about the characterization of the Ti-6Al-7Nb alloy treated by two innovative surface treatments. They consist of blasting, followed by a two step chemical etching and heat treatment performed in air or in vacuum. TEM, XRD and SEM investigations were performed in order to assess the structure and morphology of the modified surfaces. The surface chemical composition was investigated by XPS ad AES analyses. The ability to interact with physiological fluids was tested by immersion of the treated materials in an acellular simulated body fluid (SBF). Metal ion concentration analyses of the fluid and SEM observations of the samples were performed after different times of soaking. The mechanical characterization involved scratch and fatigue tests.The surface of treated samples shows chemical, structural and morphological modifications. The passivation pre-treatment has influence on the surface modification. The treated samples evidenced a quite low metal ion release and interact with SBF solution, showing a moderate bioactivity. A relevant decrease in fatigue strength was observed on modified samples.     

A novel approach for automatic text analysis and generation for the cultural heritage domain

Knowledge is information that has been contextualised in a certain domain, to be used or applied. It represents the basic core of our Cultural Heritage and Natural Language provides us with prime versatile means of construing experience at multiple levels of organization. The natural language generation field consists in the creation of texts providing information contained in other kind of sources (numerical data, graphics, taxonomies and ontologies or even other texts), with the aim of making such texts indistinguishable, as far as possible, from those created by humans. On the other hand, the knowledge extraction, basing on text mining and text analysis tasks, as examples of the many applications born from computational linguistic, provides summarization, categorization, topics extractions from textual resources using linguistic concepts, which deal with the imprecision and ambiguity of human language. This paper presents a research activity focused on exploring and scientifically describing knowledge structure and organization involved in textual resources’ generation. Thus, a novel multidimensional model for the representation of conceptual knowledge, is proposed. Furthermore, a real case study in the Cultural Heritage domain is described to demonstrate the effectiveness and the feasibility of the proposed model and approach.