Efficacy of Au−Au Contacts for Scanning Tunneling Microscopy Molecular Conductance Measurements

We measured conductance traces while breaking gold point contacts in a solution of molecules containing the μ-p-phenylenediethynyl X−C⋮C−C6H4−C⋮C−X unit, with eight different capping X groups:  Au−P(OMe)3 (1), H (2), SiMe3 (3), Au−P(cy)3 (4), Au−PMe2Ph (5), Au−PMePh2 (6), Au−PMe3 (7), and Au−PPh3 (8). Our goal with this work was to achieve a direct Au−C link with a conjugated organic group, potentially forming a molecular junction without chemical link groups that typically decrease junction conductances, such as thiols or amines. Conductance traces collected in the presence of molecules 1, 2, 3, 5, and 7 reveal additional steps at conductances as high as 0.1 G0 (G0 = 2e2/h) down to the measurable limits of the experimental setup. Conductance histograms generated from these traces therefore show a broad increase of counts when compared to a control histogram collected in the solvent alone suggesting the binding of the molecules to the broken Au contacts. The histograms for molecules 1, 5, 7, and 2 were not distinguishable, although that of molecule 3 had considerably fewer counts over the entire conductance range, suggesting that the steric bulk of the SiMe3 prevented frequent junction formation. The histograms collected in a solution of molecules 4, 6, or 8 did not differ from that of the control histogram probably because of the steric bulk of the Au−PR3 capping groups prevented the formation a molecular junction

Efficacy of Au−Au Contacts for Scanning Tunneling Microscopy Molecular Conductance Measurements

We measured conductance traces while breaking gold point contacts in a solution of molecules containing the μ-p-phenylenediethynyl X−C⋮C−C6H4−C⋮C−X unit, with eight different capping X groups:  Au−P(OMe)3 (1), H (2), SiMe3 (3), Au−P(cy)3 (4), Au−PMe2Ph (5), Au−PMePh2 (6), Au−PMe3 (7), and Au−PPh3 (8). Our goal with this work was to achieve a direct Au−C link with a conjugated organic group, potentially forming a molecular junction without chemical link groups that typically decrease junction conductances, such as thiols or amines. Conductance traces collected in the presence of molecules 1, 2, 3, 5, and 7 reveal additional steps at conductances as high as 0.1 G0 (G0 = 2e2/h) down to the measurable limits of the experimental setup. Conductance histograms generated from these traces therefore show a broad increase of counts when compared to a control histogram collected in the solvent alone suggesting the binding of the molecules to the broken Au contacts. The histograms for molecules 1, 5, 7, and 2 were not distinguishable, although that of molecule 3 had considerably fewer counts over the entire conductance range, suggesting that the steric bulk of the SiMe3 prevented frequent junction formation. The histograms collected in a solution of molecules 4, 6, or 8 did not differ from that of the control histogram probably because of the steric bulk of the Au−PR3 capping groups prevented the formation a molecular junction

Variability of Conductance in Molecular Junctions

The conductance of molecular junctions, formed by breaking gold point contacts dressed with various thiol functionalized organic molecules, is measured at 293 K and at 30 K. In the presence of molecules, individual conductance traces measured as a function of increasing gold electrode displacement show clear steps below the quantum conductance steps of the gold contact. These steps are distributed over a wide range of molecule-dependent conductance values. Histograms constructed from all conductance traces therefore do not show clear peaks either at room or low temperatures. Filtering of the data sets by an objective automated procedure only marginally improves the visibility of such features. We conclude that the geometrical junction to junction variations dominate the conductance measurements

Association between BSES scores and the primary outcome.

Association between BSES scores and the primary outcome.</p

A Randomized Controlled Trial of Innovative Postpartum Care Model for Mother-Baby Dyads

ObjectiveTo evaluate the efficacy, safety, and maternal satisfaction of a newly established integrative postpartum community-based clinic providing comprehensive support for mothers during the first month after discharge from the hospital. Our primary interests were breastfeeding rates, readmission and patient satisfaction.MethodsA randomized controlled trial was conducted in Ottawa, Canada, where 472 mothers were randomized via a 1:2 ratio to either receive standard of care (n = 157) or to attend the postpartum breastfeeding clinic (n = 315). Outcome data were captured through questionnaires completed by the participants at 2, 4, 12 and 24 weeks postpartum. Unadjusted and adjusted logistic regression models were conducted to determine the effect of the intervention on exclusive breastfeeding at 12 weeks (primary outcome). Secondary outcomes included breastfeeding rate at 2, 4 and 24 weeks, breastfeeding self-efficacy scale, readmission rate, and satisfaction score.ResultsMore mothers in the intervention group (n = 195, 66.1%) were exclusively breastfeeding at 12 weeks compared to mothers in the control group (n = 81, 60.5%), however no statistically significant difference was observed (OR = 1.28; 95% CI:0.84–1.95)). The rate of emergency room visits at 2 weeks for the intervention group was 11.4% compared to the standard of care group (15.2%) (OR = 0.69; 95% CI: 0.39–1.23). The intervention group was significantly more satisfied with the overall care they received for breastfeeding compared to the control group (OR = 1.96; 95% CI: 3.50–6.88)).ConclusionThis new model of care did not significantly increase exclusive breastfeeding at 12 weeks. However, there were clinically meaningful improvements in the rate of postnatal problems and satisfaction that support this new service delivery model for postpartum care. A community-based multidisciplinary postpartum clinic is feasible to implement and can provide appropriate and highly satisfactory care to mother-baby dyads. This model of care may be more beneficial in a population that is not already predisposed to breastfeed.Trial RegistrationClinicalTrials.gov NCT02043119</div

Secondary outcome for use of healthcare resources.

<p>Secondary outcome for use of healthcare resources.</p

Mother Demographics Characteristics.

<p>Mother Demographics Characteristics.</p

Maternal Satisfaction.

<p>Maternal Satisfaction.</p

Secondary outcomes on Breastfeeding Self-Efficacy Scale and Edinburgh Postpartum Depression Score.

<p>Secondary outcomes on Breastfeeding Self-Efficacy Scale and Edinburgh Postpartum Depression Score.</p

Breastfeeding outcomes at 2, 4, 12 and 24 weeks postpartum.

Breastfeeding outcomes at 2, 4, 12 and 24 weeks postpartum.</p