Composites à matrice cimentaire renforcée par des polymères hydrosolubles : étude de l'hydratation et des relations entre microstructure et propriétés mécaniques en flexion

Doctorat en Sciences appliquées -- UCL, 200

Dynamic mechanical thermoanalysis of latexes in cement paste

A new approach is proposed to analyze small amounts of polymer in a cement paste by means of a dynamic mechanical thermoanalyser. The polymer-cement ratio is determined from the drop in the storage modulus E' at the glass transition of the polymer. Different calibration curves are determined by analyzing the viscoelastic behaviour of the polymer in the cement from storage or loss moduli and the dissipation factor tan delta. This technique is very sensitive, which makes it possible to calculate a polymer rate accuracy better than +/-5%, even in the case of a very porous material, when the polymer rate is lower than 10% by weight. (C) 1999 Elsevier Science Ltd. All rights reserved

Reinforcement of hydrated portland cement with high molecular mass water-soluble polymers

A small amount of polymer in water solution form (polyvinylpyrolidone or polyvinylalcohol) was added to a mix high silicate cement + amorphous silica, with reduced water to cement ratio. It was shown that as the molecular mass of the polymer is increased, the fracture stress and the stored energy at fracture of the specimens improved. The polymer induces an increase of the critical stress intensity factor (K,,) (crack initiation). The fracture behaviour of the polymer modified cement paste beyond the elastic domain is also affected by PVA or PVP additions. The dissipated energy measured using the crack opening displacement CMOD was increased by a factor of two with 4wt% of PVP and by a factor of three with 3wt% of PVA, as a consequence of operative toughening mechanisms. The increase of mechanical properties is explained in case of PVP by crack interactions due to CSH microstructure modifications, and with PVA by crack bridging mechanisms as a consequence of dispersed polymer rich nodules in the hydrates phase

Randomized Phase II Trial of Atovaquone with Pyrimethamine or Sulfadiazine for Treatment of Toxoplasmic Encephalitis in Patients with Acquired Immunodeficiency Syndrome: ACTG 237/ANRS 039 Study

In this international, noncomparative, randomized phase II trial, we evaluated the effectiveness and tolerance of atovaquone suspension (1500 mg orally twice daily) plus either pyrimethamine (75 mg per day after a 200-mg loading dose) or sulfadiazine (1500 mg 4 times daily) as treatment for acute disease (for 6 weeks) and as maintenance therapy (for 42 weeks) for toxoplasmic encephalitis (TE) in patients infected with human immunodeficiency virus. Twenty-one (75%) of 28 patients receiving pyrimethamine (95% lower confidence interval [CI], 58%) and 9 (82%) of 11 patients receiving sulfadiazine (95% lower CI, 53%) responded to treatment for acute disease. Of 20 patients in the maintenance phase, only 1 experienced relapse. Eleven (28%) of 40 eligible patients discontinued treatment as a result of adverse events, 9 because of nausea and vomiting or intolerance of the taste of the atovaquone suspension. Although gastrointestinal side effects were frequent, atovaquone-containing regimens are otherwise well tolerated and safe and may be useful for patients intolerant of standard regimens for toxoplasmic encephalitis

Photocatalytic Degradation of Hexaethylene Glycol

International audienc

Toxicogenomics of nevirapine-associated cutaneous and hepatic adverse events among populations of African, Asian, and European descent

OBJECTIVE Nevirapine is widely prescribed for HIV-1 infection. We characterized relationships between nevirapine-associated cutaneous and hepatic adverse events and genetic variants among HIV-infected adults. DESIGN We retrospectively identified cases and controls. Cases experienced symptomatic nevirapine-associated severe (grade III/IV) cutaneous and/or hepatic adverse events within 8 weeks of initiating nevirapine. Controls did not experience adverse events during more than 18 weeks of nevirapine therapy. METHODS Cases and controls were matched 1: 2 on baseline CD4 T-cell count, sex, and race. Individuals with 150 or less CD4 T cells/μl at baseline were excluded. We characterized 123 human leukocyte antigen (HLA) alleles and 2744 single-nucleotide polymorphisms in major histocompatibility complex (MHC) and drug metabolism and transport genes. RESULTS We studied 276 evaluable cases (175 cutaneous adverse events, 101 hepatic adverse events) and 587 controls. Cutaneous adverse events were associated with CYP2B6 516G→T (OR 1.66, all), HLA-Cw*04 (OR 2.51, all), and HLA-B*35 (OR 3.47, Asians; 5.65, Thais). Risk for cutaneous adverse events was particularly high among Blacks with CYP2B6 516TT and HLA-Cw*04 (OR 18.90) and Asians with HLA-B*35 and HLA-Cw*04 (OR 18.34). Hepatic adverse events were associated with HLA-DRB*01 (OR 3.02, Whites), but not CYP2B6 genotypes. Associations differed by population, at least in part reflecting allele frequencies. CONCLUSION Among patients with at least 150 CD4 T cells/μl, polymorphisms in drug metabolism and immune response pathways were associated with greater likelihood of risk for nevirapine-related adverse events. Results suggest fundamentally different mechanisms of adverse events: cutaneous, most likely MHC class I-mediated, influenced by nevirapine CYP2B6 metabolism; hepatic, most likely MHC class II-mediated and unaffected by such metabolism. These risk variants are insensitive for routine clinical screening

Safety and efficacy of doravirine as first-line therapy in adults with HIV-1:week 192 results from the open-label extensions of the DRIVE-FORWARD and DRIVE-AHEAD phase 3 trials

Background: In two phase 3 trials for first-line therapy in adults with HIV-1, doravirine showed non-inferior efficacy, a favourable safety profile, and a superior lipid profile to darunavir and efavirenz through to 48 and 96 weeks. Here we report 192-week results from both studies. Methods: DRIVE-FORWARD and DRIVE-AHEAD are multicentre, double-blind, randomised, active comparator-controlled, phase 3 trials of first-line antiretroviral treatment in adults with HIV-1. Eligible participants (aged ≥18 years) were naive to antiretroviral therapy, had plasma HIV-1 RNA 1000 copies per mL or more at screening, had no known resistance to any of the trial drugs, and had creatinine clearance 50 mL per min or more. DRIVE-FORWARD was conducted at 125 sites in 15 countries and compared doravirine (100 mg) with ritonavir-boosted darunavir (ritonavir [100 mg] and darunavir [800 mg]), each administered orally once daily with two nucleoside or nucleotide reverse transcriptase inhibitors (tenofovir disoproxil fumarate [300 mg] and emtricitabine [200 mg] or abacavir sulfate [600 mg] and lamivudine [300 mg]). DRIVE-AHEAD was conducted at 126 sites in 23 countries and compared doravirine (100 mg), lamivudine (300 mg), and tenofovir disoproxil fumarate (300 mg) with that of efavirenz (600 mg), emtricitabine (200 mg), and tenofovir disoproxil fumarate (300 mg), all administered orally once daily. DRIVE-FORWARD enrolment was between Dec 1, 2014, and June 1, 2020, and DRIVE-AHEAD enrolment was between June 10, 2015, and Aug 10, 2020. After the 96-week double-blind phase, eligible participants could enter an open-label extension and either continue doravirine or switch from comparator to doravirine for an additional 96 weeks. Efficacy (HIV-1 RNA &lt;50 copies per mL) and safety assessments (adverse events and changes in laboratory parameters) were pooled. The DRIVE-FORWARD and DRIVE-AHEAD trials were registered with ClinicalTrials.gov, NCT02275780 and NCT02403674. Findings: Of 1494 participants treated in the double-blind phase (1261 [84%] male and 233 [16%] female), 550 continued doravirine and 502 switched to doravirine in the extension. Using the FDA snapshot approach, HIV-1 RNA less than 50 copies per mL was maintained in 457 (83%) of 550 participants who continued doravirine and 404 (80%) of 502 participants who switched to doravirine. Protocol-defined virological failure and development of resistance were low, occurring mainly before week 96. Two (&lt;1%) of 550 participants who continued doravirine reported serious drug-related adverse events, and three (1%) who continued doravirine and one (&lt;1%) of 502 who switched to doravirine discontinued due to drug-related adverse events. Participants continuing or switching to doravirine showed generally favourable lipid profiles, little weight gain, and small decreases in estimated glomerular filtration rates, with no discontinuations due to increased creatinine or renal adverse events. Interpretation: Favourable efficacy and safety profiles for doravirine at week 96 were maintained through to week 192 in participants who continued or switched to doravirine, supporting use of doravirine for long-term first-line HIV-1 treatment and for virologically suppressed adults switching therapy. Funding: Merck Sharp &amp; Dohme, a subsidiary of Merck &amp; Co, Rahway, NJ, USA.</p

Safety and efficacy of doravirine as first-line therapy in adults with HIV-1:week 192 results from the open-label extensions of the DRIVE-FORWARD and DRIVE-AHEAD phase 3 trials

Background: In two phase 3 trials for first-line therapy in adults with HIV-1, doravirine showed non-inferior efficacy, a favourable safety profile, and a superior lipid profile to darunavir and efavirenz through to 48 and 96 weeks. Here we report 192-week results from both studies. Methods: DRIVE-FORWARD and DRIVE-AHEAD are multicentre, double-blind, randomised, active comparator-controlled, phase 3 trials of first-line antiretroviral treatment in adults with HIV-1. Eligible participants (aged ≥18 years) were naive to antiretroviral therapy, had plasma HIV-1 RNA 1000 copies per mL or more at screening, had no known resistance to any of the trial drugs, and had creatinine clearance 50 mL per min or more. DRIVE-FORWARD was conducted at 125 sites in 15 countries and compared doravirine (100 mg) with ritonavir-boosted darunavir (ritonavir [100 mg] and darunavir [800 mg]), each administered orally once daily with two nucleoside or nucleotide reverse transcriptase inhibitors (tenofovir disoproxil fumarate [300 mg] and emtricitabine [200 mg] or abacavir sulfate [600 mg] and lamivudine [300 mg]). DRIVE-AHEAD was conducted at 126 sites in 23 countries and compared doravirine (100 mg), lamivudine (300 mg), and tenofovir disoproxil fumarate (300 mg) with that of efavirenz (600 mg), emtricitabine (200 mg), and tenofovir disoproxil fumarate (300 mg), all administered orally once daily. DRIVE-FORWARD enrolment was between Dec 1, 2014, and June 1, 2020, and DRIVE-AHEAD enrolment was between June 10, 2015, and Aug 10, 2020. After the 96-week double-blind phase, eligible participants could enter an open-label extension and either continue doravirine or switch from comparator to doravirine for an additional 96 weeks. Efficacy (HIV-1 RNA &lt;50 copies per mL) and safety assessments (adverse events and changes in laboratory parameters) were pooled. The DRIVE-FORWARD and DRIVE-AHEAD trials were registered with ClinicalTrials.gov, NCT02275780 and NCT02403674. Findings: Of 1494 participants treated in the double-blind phase (1261 [84%] male and 233 [16%] female), 550 continued doravirine and 502 switched to doravirine in the extension. Using the FDA snapshot approach, HIV-1 RNA less than 50 copies per mL was maintained in 457 (83%) of 550 participants who continued doravirine and 404 (80%) of 502 participants who switched to doravirine. Protocol-defined virological failure and development of resistance were low, occurring mainly before week 96. Two (&lt;1%) of 550 participants who continued doravirine reported serious drug-related adverse events, and three (1%) who continued doravirine and one (&lt;1%) of 502 who switched to doravirine discontinued due to drug-related adverse events. Participants continuing or switching to doravirine showed generally favourable lipid profiles, little weight gain, and small decreases in estimated glomerular filtration rates, with no discontinuations due to increased creatinine or renal adverse events. Interpretation: Favourable efficacy and safety profiles for doravirine at week 96 were maintained through to week 192 in participants who continued or switched to doravirine, supporting use of doravirine for long-term first-line HIV-1 treatment and for virologically suppressed adults switching therapy. Funding: Merck Sharp &amp; Dohme, a subsidiary of Merck &amp; Co, Rahway, NJ, USA.</p