Calcium aluminate cement in castable alumina: From hydrate bonding to the in situ formation of calcium hexaluminate

Calcium hexaluminate (CA₆) is an intrinsically densification-resistant material, therefore, its porous structures are key materials for applications as high-temperature thermal insulators. This article reports on the combination of calcined alumina and calcium aluminate cement (CAC) in castable aqueous suspensions for the in situ production of porous CA₆. The CAC content (10–34 vol%) and the curing conditions ensure structural integrity prior to sintering and maximize the development of hydrated phases. Changes in physical properties, crystalline phases, and microstructure were investigated after isothermal treatments (120–1500 °C), and three sequential porogenic events were observed. The hydration of CAC preserved the water-derived pores (up to 120 °C), and the dehydroxylation of CAC hydrates (250–700 °C) generated inter-particles pores. Moreover, the in situ expansive formation of CA₂ and CA₆ (900–1500 °C) hindered densification and generated intra-particle pores. Such events differed from those observed with other CaO sources, and resulted in significantly higher pores content and lower thermal conductivity.     

Experiencing CSCL: from motivation to the embodied experience and beyond

International Journal of Computer-Supported Collaborative Learning -     

Building community together: towards equitable CSCL practices and processes

International Journal of Computer-Supported Collaborative Learning -     

AXL Receptor in Breast Cancer: Molecular Involvement and Therapeutic Limitations

Breast cancer was one of the first malignancies to benefit from targeted therapy, i.e., treatments directed against specific markers. Inhibitors against HER2 are a significant example and they improved the life expectancy of a large cohort of patients. Research on new biomarkers, therefore, is always current and important. AXL, a member of the TYRO-3, AXL and MER (TAM) subfamily, is, today, considered a predictive and prognostic biomarker in many tumor contexts, primarily breast cancer. Its oncogenic implications make it an ideal target for the development of new pharmacological agents; moreover, its recent role as immune-modulator makes AXL particularly attractive to researchers involved in the study of interactions between cancer and the tumor microenvironment (TME). All these peculiarities characterize AXL as compared to other members of the TAM family. In this review, we will illustrate the biological role played by AXL in breast tumor cells, highlighting its molecular and biological features, its involvement in tumor progression and its implication as a target in ongoing clinical trials.     

Synthesis and characterization of a pyrochlore solid solution in the Na2O-Bi2O3-TiO2 system

The compositional limits of a previously reported (J. Am. Ceram. Soc., 61, 5-8. (1978)) but relatively unstudied sodium-bismuth titanate pyrochlore solid solution are revised and their electrical properties presented. The pyrochlore solid solution we report forms via a different mechanism to that originally reported and occurs in a different location within the Na₂O-Bi₂O₃-TiO₂ ternary system. In both cases, relatively large amounts of vacancies are required on the A-sites and on the oxygen sites, similar to that reported for undoped ‘Bi₂Ti₂O₇’ pyrochlore. In contrast to ‘Bi₂Ti₂O₇’, this ternary pyrochlore solid solution can be prepared and ceramics sintered using conventional solid-state methods; however, the processing requires several challenges to be overcome to obtain dense ceramics. This cubic pyrochlore series has low electrical conductivity (and does not exhibit any evidence of oxide-ion conduction) and exhibits relaxor ferroelectric behavior with a broad permittivity maximum of ~100 near room temperature. Variable temperature neutron diffraction data do not provide any conclusive evidence for a phase transition in the pyrochlore solid solution between ~4 and 873 K.     

Hydrolytic degree and antioxidant activity of purified casein characterised by different haplotypes (αs1-, β- and k-casein) after enzymatic hydrolysis with pepsin and enzymatic extract from Pleurotus eryngii

The aim of this study was to estimate the hydrolytic degree and antioxidant activity of purified casein characterised by different haplotypes (α_s1-, β- and k-casein) after in vitro digestion with two different enzymatic systems: pepsin from porcine gastric mucosa (EP) and a crude enzymatic extract from the edible mushroom Pleurotus eryngii. The used enzymes showed a different mode of casein catalysis with a consequent production of peptides of different antioxidant activity. The CN haplotype significantly influenced peptides production; in fact, the amino acid substitutions caused by genetic polymorphisms at the α_s1-, β- and k-CN loci influenced the sites of enzymatic cleavage and therefore the produced peptides. The above is evidenced by the different antioxidant activity found in the hydrolysates depending on the used enzymatic system, the CN haplotype, and the CN haplotype × enzymatic treatment interaction. The findings of this study are a perspective for the production of specific foods that exert a biological effect in addition to the nutritional one.     

Supporting perspective taking across chasms of thinking: Do real-time analytics hold the key?

International Journal of Computer-Supported Collaborative Learning -