Modulating the luminance of organic light emitting diodes Via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode

Self-assembled monolayers (SAMs) deposited on bottom electrodes are commonly used to tune charge carrier injection or blocking in optoelectronic devices. Beside the enhancement of device performance, the fabrication of multifunctional devices in which the output can be modulated by multiple external stimuli remains a challenging target. In this work, we report the functionalization of an indium tin oxide (ITO) electrode with a SAM of a diarylethene derivative designed for optically control the electronic properties. Following the demonstration of dense SAM formation and its photochromic activity, as a proof-of-principle, an organic light-emitting diode (OLED) embedding the light-responsive SAM-covered electrode was fabricated and characterized. Optically addressing the two-terminal device by irradiation with ultraviolet light doubles the electroluminescence. The original value can be restored reversibly by irradiation with visible light. This expanded functionality is based on the photoinduced modulation of the electronic structure of the diarylethene isomers, which impact the charge carriers' confinement within the emissive layer. This approach could be successfully exploited in the field of opto-communication technology, for example to fabricate opto-electronic logic circuits

A Comparison of Two Measures of HIV Diversity in Multi-Assay Algorithms for HIV Incidence Estimation

Background: Multi-assay algorithms (MAAs) can be used to estimate HIV incidence in cross-sectional surveys. We compared the performance of two MAAs that use HIV diversity as one of four biomarkers for analysis of HIV incidence. Methods: Both MAAs included two serologic assays (LAg-Avidity assay and BioRad-Avidity assay), HIV viral load, and an HIV diversity assay. HIV diversity was quantified using either a high resolution melting (HRM) diversity assay that does not require HIV sequencing (HRM score for a 239 base pair env region) or sequence ambiguity (the percentage of ambiguous bases in a 1,302 base pair pol region). Samples were classified as MAA positive (likely from individuals with recent HIV infection) if they met the criteria for all of the assays in the MAA. The following performance characteristics were assessed: (1) the proportion of samples classified as MAA positive as a function of duration of infection, (2) the mean window period, (3) the shadow (the time period before sample collection that is being assessed by the MAA), and (4) the accuracy of cross-sectional incidence estimates for three cohort studies. Results: The proportion of samples classified as MAA positive as a function of duration of infection was nearly identical for the two MAAs. The mean window period was 141 days for the HRM-based MAA and 131 days for the sequence ambiguity-based MAA. The shadows for both MAAs were <1 year. Both MAAs provided cross-sectional HIV incidence estimates that were very similar to longitudinal incidence estimates based on HIV seroconversion. Conclusions: MAAs that include the LAg-Avidity assay, the BioRad-Avidity assay, HIV viral load, and HIV diversity can provide accurate HIV incidence estimates. Sequence ambiguity measures obtained using a commercially-available HIV genotyping system can be used as an alternative to HRM scores in MAAs for cross-sectional HIV incidence estimation

Using Conversation Analysis in the Lab

In this introduction to the special issue of Research on Language and Social Interaction on “Experimental and Laboratory Approaches to Conversation Analysis,” I make the case that while naturalistic observation should take precedence over other methods, Conversation Analysis as a field should embrace a methodological pluralism that includes not only quantification but also experimentation and laboratory observation. Before I introduce the contributions to the special issue, I discuss the prohibition against such meth- ods in the field, situate naturalistic and laboratory research on a methodologi- cal continuum, and develop a series of arguments in favor of experimental and laboratory studies of interaction

Cost effectiveness of potential ART adherence monitoring interventions in sub-saharan Africa

Background Interventions based around objective measurement of adherence to antiretroviral drugs for HIV have potential to improve adherence and to enable differentiation of care such that clinical visits are reduced in those with high adherence. It would be useful to understand the approximate upper limit of cost that could be considered for such interventions of a given effectiveness in order to be cost effective. Such information can guide whether to implement an intervention in the light of a trial showing a certain effectiveness and cost. Methods An individual-based model, calibrated to Zimbabwe, which incorporates effects of adherence and resistance to antiretroviral therapy, was used to model the potential impact of adherence monitoring-based interventions on viral suppression, death rates, disability adjusted life years and costs. Potential component effects of the intervention were: enhanced average adherence when on ART, reduced risk of ART discontinuation, and reduced risk of resistance acquisition. We considered a situation in which viral load monitoring is not available and one in which it is. In the former case, it was assumed that care would be differentiated based on the adherence level, with fewer clinic visits in those demonstrated to have high adherence. In the latter case, care was assumed to be primarily differentiated according to viral load level. The maximum intervention cost required to be cost effective was calculated based on a cost effectiveness threshold of $500 per DALY averted. Findings In the absence of viral load monitoring, an adherence monitoring-based intervention which results in a durable 6$50 per person-year on ART, mainly driven by the cost savings of differentiation of care. In the presence of viral load monitoring availability, an intervention with a similar effect on viral load suppression was cost-effective when costing $23-$32 per year, depending on whether the adherence intervention is used to reduce the level of need for viral load measurement. Conclusion The cost thresholds identified suggest that there is clear scope for adherence monitoringbased interventions to provide net population health gain, with potential cost-effective use in situations where viral load monitoring is or is not available. Our results guide the implementation of future adherence monitoring interventions found in randomized trials to have health benefit

Imperative Directives: Orientations to Accountability

Our analysis proceeds from the question that if grammar alone is insufficient to identify the action of an imperative (e.g., offering, directing, warning, begging, etc.), how can interlocutors come to recognize the specific action being performed by a given imperative? We argue that imperative directives that occur after the directed action could have first been relevantly performed explicitly to direct the actions of the recipient and tacitly treat the absence of the action as a failure for which the recipient is accountable. The tacit nature of the accountability orientation enables both parties to focus on restoring progressivity to the directed course of action rather than topicalizing a transgression. Data are from everyday interactions in British and American English

Dynamically Switching the Electronic and Electrostatic Properties of Indium Tin Oxide Electrodes with Photochromic Monolayers Toward Photoswitchable Optoelectronic Devices

The chemical modification of electrodes with organic materials is a common approach to tuning the electronic and electrostatic landscapes between interlayers in optoelectronic devices, thus facilitating charge injection at the electrode/semiconductor interfaces and improving their performance. The use of photochromic molecules for surface modification allows a dynamic control of the electronic and electrostatic properties of the electrode and thereby enables additional functionalities in such devices. Here, we show that the electronic properties of a transparent indium–tin oxide (ITO) electrode are reversibly and dynamically modified by depositing organic photochromic switches (diarylethenes) in the form of self-assembled monolayers (SAMs). By combining a range of surface characterization and density functional theory calculations, we present a detailed picture of the SAM binding to ITO, the packing density of molecules, their orientation, and work function modification of the ITO surface due to SAM deposition. Upon illumination with UV and green light, we observe a reversible shift of the frontier occupied levels by 0.7 eV and concomitantly a reversible work function change of ca. 60 meV. Our results prove the viability of dynamic switching of the electronic properties of the electrode with external light stimuli upon modification with a monolayer of photochromic molecules, which could be used to fabricate ITO-based photoswitchable optoelectronic devices

I-Challenges: Influencing Others’ Perspectives by Mentioning Personal Experiences in Therapeutic Community Group Meetings

PINO, M., 2017. I-challenges: influencing others’ perspectives by mentioning personal experiences in therapeutic-community group meetings. Social Psychology Quarterly, 80(3), pp. 217–242. SAGE © American Sociological Association. Reprinted by permission of SAGE Publications. http://journals.sagepub.com/doi/10.1177/0190272517706048In this paper I examine the communicative practice of mentioning a personal experience as a vehicle for challenging a peer’s perspective. I study this in the context of Therapeutic Community (TC) group meetings for clients recovering from drug misuse. Using conversation analysis, I demonstrate that TC clients use this practice, which I call an I-challenge, to influence how their peers make sense of their own experiences, and to do so without commenting on those peers’ experiences and perspectives. This study highlights the power of talking in the first person as a means of influencing others–a notion previously made popular by Thomas Gordon’s work on ‘I-messages’. Additionally, this study illustrates a novel way of studying social influence. Whereas previous research in social psychology has focused on the cognitive constraints behind phenomena of social influence and persuasion, here I contribute towards understandings of the interactional norms underlying the organisation of influence as a structured and coordinated domain of social practice