Single walled carbon nanotube channel flow electrode : hydrodynamic voltammetry at the nanomolar level

The use of single walled carbon nanotube (SWNT) band electrodes in a channel flow cell, for low concentration detection, with hydrodynamic voltammetry is reported. A two dimensional SWNT network electrode is combined with a one piece channel flow cell unit, fabricated by microstereolithography. This configuration provides well defined hydrodynamics over a wide range of volume flow rates (0.05–25 mL min− 1). Limiting current measurements, from linear sweep voltammograms, are in good agreement with the channel electrode Levich equation, for the one electron oxidation of ferrocenylmethyl trimethylammonium (FcTMA+), over a wide concentration range, 1 × 10− 8 M to 2.1 × 10− 5 M, with a detection limit of 5 nM. At the highest flow rates, some influence of the slightly recessed electrode geometry arising from the SWNT electrode fabrication is noted. However, this can be accounted for by a full simulation of the hydrodynamics and solution of the resulting convection–diffusion equation. Application of this hydrodynamic configuration to the voltammetric detection of dopamine is also demonstrated

In situ scanning electrochemical probe microscopy for energy applications

High resolution electrochemical imaging methods provide opportunities to study localized phenomena on electrode surfaces. Here, we review recent advances in scanning electrochemical microscopy (SECM) to study materials involved in (electrocatalytic) energy-related applications. In particular, we discuss SECM as a powerful screening technique and also advances in novel techniques based on micro- and nanopipets, such as the scanning micropipet contact method and scanning electrochemical cell microscopy and their use in energy-related research

Alien Registration- Macpherson, Fred R. (Fort Fairfield, Aroostook County)

https://digitalmaine.com/alien_docs/36104/thumbnail.jp

BED AND BREAKFAST: THE ROLE OF SLEEP AND AFFECT IN BREAKFAST INTAKE

Breakfast intake is associated with numerous positive physical and mental health outcomes, yet breakfast skipping remains common in adults. Chronotype and sleep show potential as predictors of breakfast intake; however the existing literature has methodological limitations and fails to examine how psychological mechanisms might explain the relation between sleep and breakfast. The current investigation explored the association of means and variability of sleep behaviors (bedtime, midsleep, sleep duration) as predictors of breakfast intake frequency and high-protein breakfast intake frequency. Additionally, the role of positive and negative affect as mediators in the sleep—breakfast association was examined. Hierarchical regressions and PROCESS parallel mediation models were conducted to assess direct and indirect associations. Variability in bedtime was a significant predictor of breakfast intake frequency, with greater variability associated with less frequent intake. Future work is necessary to examine further the association of sleep and breakfast behaviors, and psychological mechanisms in this relation

The teaching of mathematics in twenty-seven senior high schools in Massachusetts

Thesis (M.A.)--Boston University, 1949. This item was digitized by the Internet Archive

The Lived Experience of Postpartum Sleep for Black and White Women

This qualitative study utilized a phenomenological research approach (van Manen, 1990), and intersectional feminist lens (Collins, 2000; Crenshaw ,1989; hooks, 2000), to uncover the lived experience of sleep in the postpartum period. Participants were 10 mothers who were less than 12 months postpartum. Data collection consisted of in-depth interviews. Data analysis procedures followed recommendations by van Manen (1990, 1997). In order to increase the trustworthiness and rigor of the study, the researcher engaged in reflexive journaling, member checking, and peer debriefing. The results were organized into six themes; 1) the importance of the sleep environment, 2) anxiety and hypervigilance, 3) adjusting to changes and finding strategies, 4) balancing self-care, 5) the emotional experience of sleep, and 6) societal expectations of mothers and sleep. Quotes from participants are included to illustrate the findings. The results are discussed in relation to the theoretical framework of the study and the existing literature. Implications for research, clinical practice, and policy are identified. Strengths and weaknesses of the study are included, as well as suggestions for future research

Effectiveness and reach of a directed-population approach to improving dental health and reducing inequalities: a cross sectional study

Background Childsmile School adopts a directed-population approach to target fluoride varnish applications to 20% of the primary one (P1) population in priority schools selected on the basis of the proportion of enrolled children considered to be at increased-risk of developing dental caries. The study sought to compare the effectiveness of four different methods for identifying individuals most in need when a directed-population approach is taken. <p></p> Methods The 2008 Basic National Dental Inspection Programme (BNDIP) cross-sectional P1 Scottish epidemiological survey dataset was used to model four methods and test three definitions of increased-risk. Effectiveness was determined by the positive predictive value (PPV) and explored in relation to 1-sensitivity and 1-specificity. <p></p> Results Complete data was available on 43470 children (87% of the survey). At the Scotland level, at least half (50%) of the children targeted were at increased-risk irrespective of the method used to target or the definition of increased-risk. There was no one method across all definitions of <i>increased-risk</i> that maximised PPV. Instead, PPV was highest when the targeting method complimented the definition of <i>increased-risk</i>. There was a higher percentage of children at <i>increased-risk</i> who were not targeted (1-sensitivity) when caries experience (rather than deprivation) was used to define <i>increased-risk</i>, irrespective of the method used for targeting. Over all three definitions of <i>increased-risk</i>, there was no one method that minimised (1-sensitivity) although this was lowest when the method and definition of <i>increased-risk</i> were complimentary. The false positive rate (1-specificity) for all methods and all definitions of <i>increased-risk</i> was consistently low (<20%), again being lowest when the method and definition of <i>increased-risk</i> were complimentary. <p></p> Conclusion Developing a method to reach all (or even the vast majority) of individuals at <i>increased-risk</i> defined by either caries experience or deprivation is difficult using a directed-population approach at a group level. There is a need for a wider debate between politicians and public health experts to decide how best to reach those most at need of intervention to improve health and reduce inequalities. <p></p&gt