Transport properties of chemically synthesized polypyrrole thin films

The electronic transport in polypyrrole thin films synthesized chemically from the vapor phase is studied as a function of temperature as well as of electric and magnetic fields. We find distinct differences in comparison to the behavior of both polypyrrole films prepared by electrochemical growth as well as of the bulk films obtained from conventional chemical synthesis. For small electric fields F, a transition from Efros-Shklovskii variable range hopping to Arrhenius activated transport is observed at 30 K. High electric fields induce short range hopping. The characteristic hopping distance is found to be proportional to F^(-1/2). The magnetoresistance R(B) is independent of F below a critical magnetic field, above which F counteracts the magnetic field induced localization.Comment: 6 pages, 5 figure

Differences in disability and nutritional status among older Brazilian and English adults: the Brazilian Longitudinal Study of Aging (ELSI-Brazil) and English Longitudinal Study of Aging (ELSA) cohorts

Background: Brazil and England are 2 countries at different stages in their demographic, epidemiological, and nutritional transitions and with distinct socioeconomic and politic contexts, but with similar universal health systems. We aimed to examine disability and its association with objective anthropometric indicators of nutritional status, including BMI, waist circumference, and waist-to-height ratio, comparing older Brazilian and English adults. / Methods: We used cross-sectional data from 2 nationally representative aging studies. For Brazil, we included 9412 participants who participated in the baseline (2015–2016) of the Brazilian Longitudinal Study of Aging (ELSI-Brazil). The English data were from 8024 participants of the wave 6 (2012–2013) of the English Longitudinal Study of Aging (ELSA). Disability was defined as difficulty to perform at least 1 activity of daily living. We used logistic regression models to examine the association between anthropometric indicators and disability, adjusted for sociodemographic and health-related characteristics, considering the interaction term between each anthropometric indicator and country. / Results: All health-related characteristics were worse in Brazil than England, although the prevalence of disability was similar among Brazilian (17.85%) and English (16.27%) older adults. Fully adjusted models showed statistically significant interaction terms between country and anthropometric indicators. The strength of the associations in Brazil was weaker compared with England. All anthropometric indicators were positively associated with disability: elevated BMI, in Brazil (OR: 1.27; 95% CI: 1.06, 1.51) and in England (OR: 1.80; 95% CI: 1.51, 2.14); elevated waist circumference, in Brazil (OR: 1.21; 95% CI: 1.02, 1.44) and in England (OR: 1.90; 95% CI: 1.51, 2.37); and elevated waist-to-height ratio, in Brazil (OR: 1.20; 95% CI: 0.96, 1.52) and in England (OR: 1.83; 95% CI: 1.37, 2.44). / Conclusions: Elevated BMI and waist circumference increased the odds of disability in both populations. However, these associations were stronger in England than in Brazil

Towards deterministically controlled InGaAs/GaAs lateral quantum dot molecules

We report on the fabrication, detailed characterization and modeling of lateral InGaAs quantum dot molecules (QDMs) embedded in a GaAs matrix and we discuss strategies to fully control their spatial configuration and electronic properties. The three-dimensional morphology of encapsulated QDMs was revealed by selective wet chemical etching of the GaAs top capping layer and subsequent imaging by atomic force microscopy (AFM). The AFM investigation showed that different overgrowth procedures have a profound consequence on the QDM height and shape. QDMs partially capped and annealed in situ for micro- photoluminescence spectroscopy consist of shallow but well-defined quantum dots (QDs) in contrast to misleading results usually provided by surface morphology measurements when they are buried by a thin GaAs layer. This uncapping approach is crucial for determining the QDM structural parameters, which are required for modeling the system. A single-band effective-mass approximation is employed to calculate the confined electron and heavy-hole energy levels, taking the geometry and structural information extracted from the uncapping experiments as inputs. The calculated transition energy of the single QDM shows good agreement with the experimentally observed values. By decreasing the edge-to-edge distance between the two QDs within a QDM, a splitting of the electron (hole) wavefunction into symmetric and antisymmetric states is observed, indicating the presence of lateral coupling. Site control of such lateral QDMs obtained by growth on a pre-patterned substrate, combined with a technology to fabricate gate structures at well-defined positions with respect to the QDMs, could lead to deterministically controlled devices based on QDMs. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

A core outcome set for pre-eclampsia research:an international consensus development study

Objective: To develop a core outcome set for pre-eclampsia. Design: Consensus development study. Setting: International. Population: Two hundred and eight-one healthcare professionals, 41 researchers and 110 patients, representing 56 countries, participated. Methods: Modified Delphi method and Modified Nominal Group Technique. Results: A long-list of 116 potential core outcomes was developed by combining the outcomes reported in 79 pre-eclampsia trials with those derived from thematic analysis of 30 in-depth interviews of women with lived experience of pre-eclampsia. Forty-seven consensus outcomes were identified from the Delphi process following which 14 maternal and eight offspring core outcomes were agreed at the consensus development meeting. Maternal core outcomes: death, eclampsia, stroke, cortical blindness, retinal detachment, pulmonary oedema, acute kidney injury, liver haematoma or rupture, abruption, postpartum haemorrhage, raised liver enzymes, low platelets, admission to intensive care required, and intubation and ventilation. Offspring core outcomes: stillbirth, gestational age at delivery, birthweight, small-for-gestational-age, neonatal mortality, seizures, admission to neonatal unit required and respiratory support. Conclusions: The core outcome set for pre-eclampsia should underpin future randomised trials and systematic reviews. Such implementation should ensure that future research holds the necessary reach and relevance to inform clinical practice, enhance women's care and improve the outcomes of pregnant women and their babies. Tweetable abstract: 281 healthcare professionals, 41 researchers and 110 women have developed #preeclampsia core outcomes @HOPEoutcomes @jamesmnduffy. [Correction added on 29 June 2020, after first online publication: the order has been corrected.].</p