A new approach to assessing the performance of ASR inhibitors in concrete

A methodological approach, based on some innovative reactivity parameters such as the threshold alkali level (TAL) of aggregates and the tolerable driving force (Delta(tol)) of the deleterious expansive process associated with alkali-silica reaction (ASR), is proposed in order to assess the alkali-reactivity of aggregates and compare the effectiveness of different types of ASR inhibitors (low-alkali Portland cements, lithium compounds, and blended cements manufactured with active mineral additions). The effectiveness of the ASR inhibitors, expressed in terms of Delta(tol), is related to the naturally available alkali content of concrete and the TAL of the aggregate used in the concrete mix. The potential minimum contribution of alkalis (L (im)) by a given ASR inhibitor to the concrete mix is proposed as a specific efficacy parameter. The relationships between the effective dose levels of mineral additions or lithium compounds and the efficacy parameters Delta(tol) and L (im) have also been identified. The test procedures for the experimental determination of such parameters are described and some methodology applications to published ASR expansion data are reported

Impact of the M184V resistance mutation on virological efficacy and durability of lamivudine-based dual antiretroviral regimens as maintenance therapy in individuals with suppressed HIV-1 RNA: A cohort study

Background. Dual therapy (DT) with boosted protease inhibitors (bPIs) plus lamivudine has been shown to be superior to bPI monotherapy in virologically suppressed patients despite previous selection of the lamivudine resistance M184V mutation. We compared the virological efficacy of lamivudine-based DT in patients with and without a history of M184V detection. Methods. We retrospectively analyzed patients with HIV-RNA ≤50 copies/mL switching to DT with at least 1 previous resistance genotype in the ARCA database. Time to virological failure (VF; HIV-RNA ≥200 copies/mL or 2 consecutive HIV-RNA >50 copies/mL) and to treatment discontinuation (TD) was analyzed by survival analysis. Results. Four hundred thirty-six patients switching to lamivudine plus bPIs (70%) or integrase inhibitors (30%) were included. Patients with M184V (n = 87) were older, had lower nadir CD4+ cell count, longer duration of antiretroviral therapy and of virologic suppression, and higher rate of hepatitis C virus infection compared with patients without M184V. The 3-year probability of remaining free from VF was 91.9% (95% confidence interval [CI], 86.6-97.2) without M184V and 87.8% (95% CI, 78.4-97.2) with M184V (P = .323). The time to TD did not differ between groups. Multivariate analysis adjusting for baseline variables differing between groups also did not detect M184V as being associated with VF or TD; however, the 3-year probability of remaining free of viral blips (isolated HIV-RNA 51-199 copies/mL) was 79.8% (95% CI, 67.8%-91.8%) with M184V vs 90.1% (95% CI, 84.0%-96.2%) without M184V (P = .016). Conclusions. Previous selection of M184V did not increase the risk of VF or TD with lamivudine-based DT but was associated with a higher probability of viral blips

Performance of genotypic tropism testing in clinical practice using the enhanced sensitivity version of Trofile as reference assay: results from the OSCAR Study Group

The goal of the OSCAR programme is to evaluate the performances of genotypic HIV-1 tropism testing in clinical practice using the enhanced sensitivity version of Trofile (ESTA) as reference-assay