Processing and characterization of Ultra High Temperature High‐Entropy (Ti0.2Zr0.2Hf0.2Mo0.2W0.2)B2-based Ceramics: Effect of W granulometry, graphite, and SiC addition

A highly dense and single phase (Ti0.2Zr0.2Hf0.2Mo0.2W0.2)B2 ceramic product is obtained in this work at 1950°C (20 min, 20 MPa) by Spark Plasma Sintering (SPS) from powders prepared by Self-propagating High-temperature Synthesis (SHS). The formation of the (W,Mo)B2 secondary phase is avoided using fine W precursors and adding 1 wt% graphite to the SHS powders before SPS. Kinetic limitations responsible for hindering the synthesis of the high entropy boride are correspondingly eliminated. The resulting 98.5 % dense sample exhibits a homogeneous microstructure, with Vickers hardness of 26.8 GPa. The introduction of 20 vol% SiC produces an increase of the KIC values from 2.32 to 5.11 MPa m1/2. Very relevant is that the volatilization of Mo- and W-oxides occurring during sample oxidation at high temperature, which leads to its rapid degradation with the formation of a very porous oxide scale, can be strongly inhibited by the silicate phases generated in the composite ceramic

Identification of a HERV-K env surface peptide highly recognized in Rheumatoid Arthritis (RA) patients: a cross-sectional case–control study

Endogenous retroviruses (HERV) are believed to be pathogenic in several autoimmune diseases. Among them, HERV-K viruses have been reported recently to be involved in the pathogenesis of rheumatoid arthritis (RA). In this study we have explored the role of humoral immune response against HERV-K as a potential pathogenetic mechanism in RA. Four different peptides from the extracellular portion of the env protein of HERV-K (env-su19–37, env-su109–126, env-su164–186, env-su209–226) were selected by bioinformatic analysis on the basis of their putative immunogenicity. Indirect enzyme-linked immunosorbent assay (ELISA) was then carried out to quantify antibodies against those peptides on blood samples of 70 consecutive RA patients and 71 healthy controls (HC). Differences between the two groups were analysed using the Mann–Whitney test. Potential correlations between RA laboratory, clinical descriptors and immunoglobulin (Ig)G levels were explored by bivariate regression analysis. Serum autoantibodies against one of four tested peptides of HERV-K (env-su19–37) were significantly higher in RA than in HC (19 versus 3%, P = 0·0025). Subgroup analysis showed no association between anti-HERV-K peptide humoral response and clinical, serological and clinimetric RA disease descriptors. Serum from RA patients in our series reacted significantly against HERV-K env-su19–37 peptide in comparison to the general population suggesting a role for the HERV-K- related, secondary antigenic-driven immune response in the pathogenesis of RA. Further studies are needed to confirm these results and to explore the role of this HERV-K surface peptide as a potential therapeutic target

Humoral immunity response to human endogenous retroviruses K/W differentiates between amyotrophic lateral sclerosis and other neurological diseases

BACKGROUND AND PURPOSE: Human endogenous retroviruses-K/W seem play a role in fostering and exacerbation of some neurological diseases, including amyotrophic lateral sclerosis (ALS). Given these findings, we investigated the immunity response against HERV-K and HERV-W envelope surface (env-su) glycoprotein antigens in serum and cerebrospinal fluid (CSF) of ALS, multiple sclerosis (MS) and Alzheimer's disease (AD) patients, and in healthy controls (HCs). METHODS: Four antigenic peptides derived respectively from HERV-K and HERV-W env surface proteins were studied in twenty-one definite or probable ALS, twenty-six possible or definite relapsing-remitting (RR) MS, eighteen patients with AD and thirty-nine HCs. An indirect ELISA was set up to detect specific antibodies (Abs) against env surface peptides. RESULTS: Among the measured levels of Abs against the four different HERV-K peptide fragments, HERV-K env-su 19-37 only was significantly elevated in ALS compared to other groups, both in serum and CSF. Instead, among the Abs levels directed against the four different HERV-W peptide fragments, only HERV-W env-su 93-108 and HERV-W env-su 248-262 were significantly elevated, in serum and CSF of MS, compared to other groups. In ALS patients, the HERV-K env-su 19-37 antibodies levels were significantly correlated with clinical measures of disease severity, both in serum and CSF. CONCLUSIONS: Increased circulating levels of Abs directed against the HERV-W env-su 93-108 and HERV-W env-su 248-262 peptide fragments could serve as possible biomarkers in patients with MS. Similarly, increased circulating levels of Abs directed against the HERV-K env-su19-37 peptide fragment could serve as possible early novel biomarker in patients with ALS. This article is protected by copyright. All rights reserved