3 research outputs found
Ătude de lâinfluence des solvants rĂ©siduels sur les Ă©lectrolytes polymĂšres pour batteries au lithium-ion
Les batteries lithium-ion sont prĂ©sentement dâexcellentes candidates pour le stockage Ă©lectrochimique dâĂ©nergie du futur. Cela dit, les batteries lithium-mĂ©tal pourraient prĂ©senter des propriĂ©tĂ©s Ă©lectrochimiques encore plus avantageuses. Cependant, ces types de batteries prĂ©sentent encore des inconvĂ©nients, notamment au niveau de leur sĂ©curitĂ©. Un des responsables majeurs de ceux-ci est lâĂ©lectrolyte liquide organique. Parmi les diffĂ©rentes voies exploitables pour amĂ©liorer la sĂ©curitĂ© de ces technologies, les Ă©lectrolytes solides polymĂšres (SPE) sont largement Ă©tudiĂ©s. Classiquement, ces systĂšmes sont mis en forme en prĂ©sence de solvants qui sont ensuite Ă©vaporĂ©s. Aussi, lorsque le processus dâĂ©vaporation de solvants est terminĂ©, les Ă©chantillons sont habituellement rĂ©exposĂ©s Ă lâair ambient. Or, dâune part, malgrĂ© le sĂ©chage important dâun Ă©chantillon, il se peut quâil reste du solvant de mise en forme rĂ©siduelle. Dâautre part, lâeau atmosphĂ©rique peut sâinfiltrer au sein de celui-ci. Cependant, ce ne sont pas des facteurs qui sont considĂ©rĂ©s dans la recherche prĂ©sente dans le domaine. Bien que lâinfluence des solvants rĂ©siduels est parfois mentionnĂ©e, elle nâest jamais quantifiĂ©e de façon convenable, et cela reste un facteur mal compris et souvent omis. Dans cette Ă©tude, des Ă©chantillons de diffĂ©rents types de SPE ont Ă©tĂ© prĂ©parĂ©s selon des conditions standards, leur teneur en solvants rĂ©siduels a Ă©tĂ© contrĂŽlĂ©e et analysĂ©e par diffĂ©rentes mĂ©thodes dĂ©veloppĂ©es au cours de cette recherche. Pour la quantification de lâeau, un analyseur dâhumiditĂ© spĂ©cifique a Ă©tĂ© utilisĂ©, et il a Ă©tĂ© montrĂ© que lâeau rĂ©siduelle permet dâaugmenter les conductivitĂ©s ioniques des Ă©chantillons. Pour la quantification des solvants rĂ©siduels organiques, une mĂ©thode analytique employant la chromatographie gazeuse couplĂ©e Ă la spectromĂ©trie de masse a Ă©tĂ© dĂ©veloppĂ©e. Il a Ă©tĂ© observĂ© que comme avec lâeau, les solvants rĂ©siduels augmentent la conductivitĂ© ionique des Ă©chantillons Ă©tudiĂ©s. Cette Ă©tude doit montrer aux chercheurs dans le domaine que le contrĂŽle des solvants rĂ©siduels est un facteur primordial dans le dĂ©veloppement des SPEs, et que câest un paramĂštre qui doit ĂȘtre systĂ©matiquement Ă©valuĂ©.Lithium-ion batteries are todayâs candidates for future long-term electrochemical storage of renewable energies. That said, lithium-metal batteries could offer even more appealing electrochemical properties. However, both types of batteries still suffer from certain technical difficulties such as safety. One of the culprits for their reduced safety is the use of an organic liquid electrolyte. Indeed, the latter is flammable and poses a risk, as numerous battery fire accidents have shown throughout the past years. Luckily, scientific research has been able to propose safer alternatives to liquid electrolytes applicable to lithium batteries by replacing the former by solid state electrolytes. Amongst these systems, solid polymer electrolytes (SPE) can be considered as a promising possibility to eliminating the safety issues. Conventionally, SPEs are prepared in a solvent that is evaporated at the end of the manufacturing. Additionally, atmospheric humidity can infiltrate these materials and alter their properties. However, residual solvent content is seldom mentioned, and even when it is, the specific experimental parameters are lacking which makes it a misunderstood and regularly omitted factor in battery performance evaluation. In this study, residual solvents are quantified in different SPE systems that are prepared according to standard and non-standard procedures. To do so, certain samples have had their solvent content artificially modified in order to control and analyse it. Firstly, water content is assessed using a specific moisture analyser. Secondly, an analytical method employing gas chromatography coupled to mass spectrometry has been developed to determine the residual SPE processing solvent. It has been concluded that, similarly to water, residual solvents also contribute to enhancing ionic conductivities of SPEs. Hopefully, this study will shed light on the importance of controlling residual solvent content in SPEs, and the necessity of systematically assessing that parameter
Ticagrelor in patients with diabetes and stable coronary artery disease with a history of previous percutaneous coronary intervention (THEMIS-PCI) : a phase 3, placebo-controlled, randomised trial
Background:
Patients with stable coronary artery disease and diabetes with previous percutaneous coronary intervention (PCI), particularly those with previous stenting, are at high risk of ischaemic events. These patients are generally treated with aspirin. In this trial, we aimed to investigate if these patients would benefit from treatment with aspirin plus ticagrelor.
Methods:
The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS) was a phase 3 randomised, double-blinded, placebo-controlled trial, done in 1315 sites in 42 countries. Patients were eligible if 50 years or older, with type 2 diabetes, receiving anti-hyperglycaemic drugs for at least 6 months, with stable coronary artery disease, and one of three other mutually non-exclusive criteria: a history of previous PCI or of coronary artery bypass grafting, or documentation of angiographic stenosis of 50% or more in at least one coronary artery. Eligible patients were randomly assigned (1:1) to either ticagrelor or placebo, by use of an interactive voice-response or web-response system. The THEMIS-PCI trial comprised a prespecified subgroup of patients with previous PCI. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke (measured in the intention-to-treat population).
Findings:
Between Feb 17, 2014, and May 24, 2016, 11â154 patients (58% of the overall THEMIS trial) with a history of previous PCI were enrolled in the THEMIS-PCI trial. Median follow-up was 3·3 years (IQR 2·8â3·8). In the previous PCI group, fewer patients receiving ticagrelor had a primary efficacy outcome event than in the placebo group (404 [7·3%] of 5558 vs 480 [8·6%] of 5596; HR 0·85 [95% CI 0·74â0·97], p=0·013). The same effect was not observed in patients without PCI (p=0·76, p interaction=0·16). The proportion of patients with cardiovascular death was similar in both treatment groups (174 [3·1%] with ticagrelor vs 183 (3·3%) with placebo; HR 0·96 [95% CI 0·78â1·18], p=0·68), as well as all-cause death (282 [5·1%] vs 323 [5·8%]; 0·88 [0·75â1·03], p=0·11). TIMI major bleeding occurred in 111 (2·0%) of 5536 patients receiving ticagrelor and 62 (1·1%) of 5564 patients receiving placebo (HR 2·03 [95% CI 1·48â2·76], p<0·0001), and fatal bleeding in 6 (0·1%) of 5536 patients with ticagrelor and 6 (0·1%) of 5564 with placebo (1·13 [0·36â3·50], p=0·83). Intracranial haemorrhage occurred in 33 (0·6%) and 31 (0·6%) patients (1·21 [0·74â1·97], p=0·45). Ticagrelor improved net clinical benefit: 519/5558 (9·3%) versus 617/5596 (11·0%), HR=0·85, 95% CI 0·75â0·95, p=0·005, in contrast to patients without PCI where it did not, p interaction=0·012. Benefit was present irrespective of time from most recent PCI.
Interpretation:
In patients with diabetes, stable coronary artery disease, and previous PCI, ticagrelor added to aspirin reduced cardiovascular death, myocardial infarction, and stroke, although with increased major bleeding. In that large, easily identified population, ticagrelor provided a favourable net clinical benefit (more than in patients without history of PCI). This effect shows that long-term therapy with ticagrelor in addition to aspirin should be considered in patients with diabetes and a history of PCI who have tolerated antiplatelet therapy, have high ischaemic risk, and low bleeding risk