Anhydrous proton conducting polymer electrolytes based on polymeric ionic liquids

Imidazolium types of ionic liquids were immobilized by tethering it to acrylate backbone. These imidazolium salt containing acrylate monomers were polymerize at 70oC by free radical polymerization to give polymers poly(AcIm-n) with n being the side chain lenght. The chemical structure of the polymer electrolytes obtained by the described synthetic routes was investigated by NMR-spectroscopy. The polymers were doped with various amounts of H3PO4 and LiN(SO2CF3)2, to obtain poly(AcIm-n) x H3PO4 and poly(AcIm-2-Li) x LiN(SO2CF3)2. The TG curves show that the polymer electrolytes are thermally stable up to about 200◦C. DSC results indicates the softening effect of the length of the spacers (n) as well as phosphoric acid. The proton conductivity of the samples increase with x and reaches to 10-2 Scm-1 at 120oC for both poly(AcIm-2)2H3PO4 and poly(AcIm-6)2H3PO4. It was observed that the lithium ion conductivity of the poly(AcIm-2-Li) x LiN(SO2CF3)2 increases with blends (x) up to certain composition and then leveled off independently from blend content. The conductivity reaches to about 10-5 S cm-1 at 30oC and 10-3 at 100oC for poly(AcIm-2-Li) x LiN(SO2CF3)2 where x is 10. The phosphate and phosphoric acid functionality in the resulting polymers, poly(AcIm-n) x H3PO4, undergoes condensation leading to the formation of cross-linked materials at elevated temperature which may improve the mechanical properties to be used as membrane materials in fuel cells. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to obtain information about hydrogen bonding in solids. The low Tg enhances molecular mobility and this leads to better resolved resonances in both the backbone region and side chain region. The mobile and immobile protons can be distinguished by comparing 1H MAS and 1H-DQF NMR spectra. The interaction of the protons which may contribute to the conductivity is observed from the 2D double quantum correlation (DQC) spectra

Substances naturelles antipaludiques (mise au point d'une méthode de détection des adduits hème-molécules par spectrométrie de masse)

Le paludisme est l'une des plus meurtrières de toutes les affections humaines. Bien qu'endémique des pays dits " en voie de développement ", bon nombre de chercheurs occidentaux ont choisi de s'investir dans cette lutte. En effet, seule la découverte de nouvelles thérapeutiques, peu coûteuses et facilement accessibles, permettra d'enrayer le développement mortel de cette affection parasitaire. Après avoir présenté la maladie, ce mémoire s'attache à décrire les récents efforts menés sur la découverte de nouvelles cibles antipaludéennes ainsi que les substances naturelles s'étant révélées actives sur les Plasmodium. Des travaux personnels destinés à détecter, par spectrométrie de masse, les substances naturelles susceptibles de former des adduits avec l'hème, sont présentés. Les premiers résultats obtenus sur des extraits de quinquina et d'armoise annuelle, montrent qu'il est possible de détecter, directement dans un extrait total de plante, les composés formant des liaisons avec l'hème.TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Double-edged Knife: Can Colistin Nephrotoxicity be Prevented with High Doses of Vitamin C?

Introduction: In this study, it was aimed to determine the risk factors for developing acute kidney injury (AKI) and effects of ascorbic acid on the development of nephrotoxicity in patients receiving systemic colistin sodium therapy. Materials and Methods: We retrospectively reviewed records of cases who were treated with systemic colistin sodium and did not have any known renal disease in our hospital between the years of 2014 and 2019. The demographic characteristics, indications for systemic colistin, other antibiotics applied and nephrotoxic drugs, vasopressor necessity, daily creatinine values, development of acute kidney injury, and ascorbic acid use were evaluated. Acute kidney injury was assessed according to KDIGO 2017. Results: Sixty-six patients were included in the study. In addition to colistin therapy, 33 cases who received at least three grams of ascorbic acid per day and 33 cases who received only colistin therapy were evaluated retrospectively. Acute kidney injury developed in 12 (36.4%) of those receiving ascorbic acid and 15 (45.5%) in those not receiving ascorbic acid (p= 0.617). Acute kidney injury developed in 9.1 +/- 5.9 days in ascorbic acid patients and 7.1 +/- 4.4 days in non-ascorbic acid patients (p= 0.314). The rate of septic shock development was significantly lower in patients receiving ascorbic acid (30.3% vs 57.6%, p= 0.046). Advanced age (p= 0.005), sepsis (p= 0.046), and underlying cardiac disease (p= 0.01) were found to be statistically significant in terms of the development of nephrotoxicity. Conclusion: Although no statistically significant effect of ascorbic acid using on the development of colistin-related nephrotoxicity was determined in our study, we think that high dose vitamin C may be beneficial in selected patient groups in terms of the fact that AKI is seen less in the group using ascorbic acid, does not have serious side effects and has a positive effect on preventing from septic shock. However further research is needed with more patients