It is challenging to reconfigure devices at molecular length scales. Here we report molecular junctions based on molecular switches that toggle stably and reliably between multiple operations to reconfigure electronic devices at molecular length scales. Rather than static on/off switches that always revert to the same state, our voltage-driven molecular device dynamically switches between high and low conduction states during six consecutive proton-coupled electron transfer steps.
View Article and Find Full Text PDFObjectives: To assess the performance of mean uterine artery pulsatility index (UtA-PI) at 18-22 and 24-28 weeks of gestation in the prediction of pre-eclampsia (PE) and small-for-gestational age (SGA), and its role in reassessing the risk of PE and SGA in pregnancies screened for PE in the first trimester.
Methods: This was a retrospective observational cohort study of 4464 women with singleton pregnancy screened routinely for PE in the first trimester, using the Gaussian algorithm, from March 2019 to May 2021, and who underwent UtA-PI assessment at 18-22 gestational weeks. Women were categorized as low risk or high risk based on the risk index obtained after first-trimester screening for PE.
Objective: Cervical insufficiency accounts for 8 % of preterm births. Pessary and cerclage are considered preventive approaches for preterm birth. These interventions were compared in terms of reducing the prematurity rate in women with previous preterm birth, due to cervical insufficiency or due to having a short cervix in their current pregnancy.
View Article and Find Full Text PDFTo develop new types of dynamic molecular devices with atomic-scale control over electronic function, new types of molecular switches are needed with time-dependent switching probabilities. We report such a molecular switch based on proton-coupled electron transfer (PCET) reaction with giant hysteric negative differential resistance (NDR) with peak-to-valley ratios of 120 ± 6.6 and memory on/off ratios of (2.
View Article and Find Full Text PDFThe performance of large-area molecular diodes can in rare cases approach the lower limit of commercial semiconductor devices but predictive structure-property design remains difficult as the rectification ratio () achieved by self-assembled monolayer (SAM) based diodes depends on several intertwined parameters. This paper describes a systematic approach to achieve high rectification in bisferrocenyl-based molecular diodes, HSCFc-CC-Fc ( = 9-15) immobilised on metal surfaces (Ag, Au and Pt). Experiments supported by molecular dynamics simulations show that the molecular length and bottom electrode influence the SAM packing, which affects the breakdown voltage (), the associated maximum (), and the bias at which the is achieved ().
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