Sustainable Modification of Chitosan Binder for Capacitive Electrodes Operating in Aqueous Electrolytes

Biopolymers emerged in recent years as a promising alternative for a more sustainable manufacturing of electrochemical energy storage systems. In fact, for environmentally friendly aqueous systems, fluorinated polymers are usually adopted. For this reason, substituting these polymers with water processable binders could improve the overall environmental impact of the device. In this study, a low – cost and environmentally friendly modification of chitosan binder for self-standing activated carbon electrodes operating in Na ion, aqueous electrochemical double layer capacitors is reported and discussed

Thorough investigation on the high-temperature polymorphism of dipentyl-perylenediimide: thermal expansion vs. polymorphic transition

N,N′-Dipentyl-3,4,9,10-perylendiimide (PDI-C5) is an organic semiconducting material which has been extensively investigated as model compound for its optoelectronic properties. It is known to be highly thermally stable, that it exhibits solid-state transitions with temperature and that thermal treatments lead to an improvement in its performance in devices. Here we report a full thermal characterization of PDI-C5 by combination of differential scanning calorimetry, variable temperature X-ray diffraction, hot stage microscopy, and variable temperature Raman spectroscopy. We identified two high temperature polymorphs, form II and form III, which form respectively at 112 °C and at 221 °C and we determined their crystal structure from powder data. Form II is completely reversible upon cooling with low hysteresis, while form III revealed a different thermal behaviour upon cooling depending on the technique and crystal size. The crystal structure features of the different polymorphs are discussed and compared, and we looked into the role of the perylene core and alkyl chains during solid-state transitions. The thermal expansion principal axis of PDI-C5 crystal forms is reported showing that all the reported forms possess negative thermal expansion (X1) and large positive thermal expansion (X3) which are correlated to thermal behaviour observed

Syphilis and blood donors. Comparison of two different diagnostic strategies

In this study the validity of the methods provided for by Italian law (VDRL or RPR tests) were compared with the diagnostic strategy suggested by WHO (the use of VDRL and TPHA tests in parallel). Sensitivity, specificity and posterior probability of infection after a positive or a negative result were estimated. The application of two tests in parallel produces a statistically significant increase of sensitivity from 47% to 98% while the increase of proportion of false positives is not significant (from 15% to 16%). Probability of infection when the result is negative to the RPR is 0.07% while a negative result to the RPR and the TPHA tests has a probability to be really infected of 0.003%. The use of the two tests (RPR and TPHA) in parallel is able to give the highest degree of sensitivity, indispensable to select possible blood donors, while maintaining a good degree of specificity. The authors concluded that the use of VDRL alone does not exclude infectivity of a blood sample, and in accordance with WHO and international recommendations, the VDRL or RPR and TPHA tests should be used in parallel for syphilis screening