Core-shell latices based on conductive polymers

A poly(butyl methacrylate) (PBMA) latex was coated with a thin polypyrrole (PPy) layer in a chemical in situ polymerization. Ammonium persulfate and Fenton's reagent were used as the oxidants. The influence of reaction time on the conversion of pyrrole and on the conductivity of the resulting coated latices was investigated. Furthermore, the influence of the reaction atmosphere was investigated. It was found that the ammonium persulfate-oxidized reaction was quite insensitive towards the reaction atmosphere, whereas the Fenton's reagent oxidized system was very sensitive. In the latter system, when kept in air the conductivity reached a maximum after 30 minutes. In a nitrogen reaction atmosphere the conductivity gradually increased. The maximum conductivity, which was about 20 times as high as in air, was reached after 90 minutes and remained stable.</p

Core-shell latices based on conductive polymers

A poly(butyl methacrylate) (PBMA) latex was coated with a thin polypyrrole (PPy) layer in a chemical in situ polymerization. Ammonium persulfate and Fenton's reagent were used as the oxidants. The influence of reaction time on the conversion of pyrrole and on the conductivity of the resulting coated latices was investigated. Furthermore, the influence of the reaction atmosphere was investigated. It was found that the ammonium persulfate-oxidized reaction was quite insensitive towards the reaction atmosphere, whereas the Fenton's reagent oxidized system was very sensitive. In the latter system, when kept in air the conductivity reached a maximum after 30 minutes. In a nitrogen reaction atmosphere the conductivity gradually increased. The maximum conductivity, which was about 20 times as high as in air, was reached after 90 minutes and remained stable

Ceramic-supported thin PVA pervaporation membranes combining high flux and high selectivity : contradicting the flux-selectivity paradigm

Thin, high-flux and highly selective cross-linked poly(vinyl)alcohol waterselective layers have been prepared on top of hollow fibre ceramic supports. The supports consist of an alpha-Al2O3 hollow fibre substrate and an intermediate gamma-Al2O3 layer, which provides a sufficiently smooth surface for the deposition of ultra-thin PVA layers. Membranes have been characterised by SEM and pervaporation experiments. The thickness of the PVA layer formed on top of the γ-Al2O3 intermediate layer is in the order of 0.3-0.8 μm. No significant infiltration of PVA into the intermediate gamma-Al2O3 layer can be observed. In the dehydration of 1 butanol (80C, 5 wt.% water) the membranes exhibit a high water flux (0.8 2.6 kg?m 2?h-1), combined with a high separation factor (500 - 10.000). The values for the flux and separation factor exceed typical values obtained for cross-linked PVA membranes on polymeric supports. In the dehydration of 2 propanol and 1 butanol, a simultaneous increase in both water flux and separation factor is observed with increasing temperature or water concentration. This remarkable behaviour is in contrast to the trade-off generally observed for polymer membranes, i.e., an increase in flux is typically combined with a decrease in separation factor. A possible explanation for this behaviour is a low degree of three dimensional swelling in the vicinity of the gamma-Al2O3 ? PVA interface due to an enhanced structural stability. In the dehydration of ethanol and 1 propanol the traditional trade-off between flux and selectivity was observe

Mortality after surgery in Europe: a 7 day cohort study

Background: Clinical outcomes after major surgery are poorly described at the national level. Evidence of heterogeneity between hospitals and health-care systems suggests potential to improve care for patients but this potential remains unconfirmed. The European Surgical Outcomes Study was an international study designed to assess outcomes after non-cardiac surgery in Europe.Methods: We did this 7 day cohort study between April 4 and April 11, 2011. We collected data describing consecutive patients aged 16 years and older undergoing inpatient non-cardiac surgery in 498 hospitals across 28 European nations. Patients were followed up for a maximum of 60 days. The primary endpoint was in-hospital mortality. Secondary outcome measures were duration of hospital stay and admission to critical care. We used χ² and Fisher’s exact tests to compare categorical variables and the t test or the Mann-Whitney U test to compare continuous variables. Significance was set at p&lt;0·05. We constructed multilevel logistic regression models to adjust for the differences in mortality rates between countries.Findings: We included 46 539 patients, of whom 1855 (4%) died before hospital discharge. 3599 (8%) patients were admitted to critical care after surgery with a median length of stay of 1·2 days (IQR 0·9–3·6). 1358 (73%) patients who died were not admitted to critical care at any stage after surgery. Crude mortality rates varied widely between countries (from 1·2% [95% CI 0·0–3·0] for Iceland to 21·5% [16·9–26·2] for Latvia). After adjustment for confounding variables, important differences remained between countries when compared with the UK, the country with the largest dataset (OR range from 0·44 [95% CI 0·19 1·05; p=0·06] for Finland to 6·92 [2·37–20·27; p=0·0004] for Poland).Interpretation: The mortality rate for patients undergoing inpatient non-cardiac surgery was higher than anticipated. Variations in mortality between countries suggest the need for national and international strategies to improve care for this group of patients.Funding: European Society of Intensive Care Medicine, European Society of Anaesthesiology