Stéphane Perrin

Portland cement is extensively used for the conditioning of radioactive waste. However, its high alkalinity is a serious obstacle to the stabilization of waste containing aluminum metal since aluminum is oxidized by the pore solution with the production of dihydrogen. This work investigates the potential of an alternative binder, magnesium potassium phosphate (MKP) cement, for the stabilization of Al–Mg alloys comprising 2 to 4.5 wt% of Mg and other metallic impurities. The objective is to assess the influence of the alloy composition on its reactivity in the cementitious matrix at earlier ages, as well as at later ages, when the cement has reached a significant reaction degree. Two complementary techniques are used. Gas chromatography shows that the dihydrogen release, resulting from the corrosion process, is not influenced by the magnesium content in the alloy. Electrochemical impedance spectroscopy provides qualitative information about the corrosion but also makes it possible to assess the corrosion current using an equivalent electrical circuit linked to the kinetic parameters of the postulated corrosion mechanism. Over a one-year period, the corrosion current of the alloys, regardless of their Mg content, is reduced by almost three orders of magnitude in MKP mortar as compared to Portland-cement-based mortar.

Cancer patients receiving chemotherapy are at increased risk of venous thromboembolism (VTE). The presence of cancer and anticoagulant use are risk factors for bleeding, yet data on bleeding risk are limited in these patients. This analysis evaluated the risk of major bleeding in cancer patients receiving chemotherapy using a US claims database. This retrospective cohort study used the MarketScan^® databases, a nationwide database containing data from about 100 payers and covering > 30 million patients annually. Adult cancer patients receiving chemotherapy within 6 months of cancer diagnosis between January 2004 and December 2010 were included. Cancers of interest were: lung, colon/rectum, pancreas, bladder, stomach, and ovary. The index date was the first date of chemotherapy. Patients were followed until the earliest of: 1) first diagnosis of major bleeding; 2) termination of enrolment in the health plan; 3) end of study. The primary outcome was the first occurrence of major bleeding, based on selected ICD-9-CM/CPT codes, following chemotherapy initiation. Of 74,575 patients identified, exclusion of those with prior history of bleeding at baseline (∼5%) resulted in 70,822 patients included in the analysis. Mean age was 62 years, 37% were ≥ 65 years, and 52% were male. Average time of follow up and chemotherapy were 14.3 and 8.6 months, respectively; 6% had a history of VTE within 6 months prior to the index date. Major bleeding occurred in 5.8% of patients and the incidence rate for all cancers combined was 4.9 per 100 person-year (PY) and 10.5, 9.3, 6.2, 4.3, 3.6, and 3.3/100 PY for pancreatic, stomach, lung, bladder, colon/rectum, and ovarian cancer, respectively. Approximately 14% of patients (N = 10,456) developed VTE after chemotherapy initiation (> half in the first 3 months of chemotherapy treatment). Of these, 7.8% experienced major bleeding with incidence rates ranging from 5.9-17.7/100 PY after VTE. Major bleeding incidence in cancer patients receiving chemotherapy varies by cancer type with the highest rates in patients with upper gastrointestinal cancer. Compared to the overall cohort, major bleeding risk was higher in cancer patients who developed VTE.

The presence of microorganisms on metal surfaces can alter the local physical/chemical conditions and lead to microbiologically influenced corrosion (MIC). The goal of the present work was to study the effect of a mixed aerobic–anaerobic biofilm on the behaviour of stainless steel (316 L) in underground conditions. Rather than testing different bacteria or consortia, investigations were based on the mechanisms of MIC. Mixed biofilms were simulated by the addition of glucose oxidase to reproduce the aerobic conditions and by sulphide or sulphate-reducing bacteria (SRB) for the anaerobic conditions. A double thermostated electrochemical cell has been developed to study the coupling between aerobic and anaerobic conditions. Results suggested a transfer of electrons from the stainless steel sample of the anaerobic cell to the stainless steel sample of the aerobic one. Inorganic sulphide was replaced by SRB in the anaerobic cell revealing an increase of the galvanic current which may be explained by an effect of lactate and/or acetate on the anodic reaction or by a high sulphide concentration in the biofilm. The results of this study underline that the dual-electrochemical cell system is representative of phenomena present in natural environments and should be considered as an option when studying MIC.