Ageing effects around the glass and melting transitions in poly(dimethylsiloxane) visualized by resistance measurements

The process of ageing in rubbers requires monitoring over long periods (days to years). To do so in non-conducting rubbers, small amounts of carbon-black particles were dispersed in a fractal network through the rubber matrix, to make the rubber conducting without modifying its properties. Continuous monitoring of the resistance reveals the structural changes around the glass and melting transitions and especially details about the hysteresis and ageing processes. We illustrate the method for the semicrystalline polymer poly(dimethylsiloxane) (PDMS).Comment: 4 pages, 4 figure

A new framework for designing programmes of assessment

Research on assessment in medical education has strongly focused on individual measurement instruments and their psychometric quality. Without detracting from the value of this research, such an approach is not sufficient to high quality assessment of competence as a whole. A programmatic approach is advocated which presupposes criteria for designing comprehensive assessment programmes and for assuring their quality. The paucity of research with relevance to programmatic assessment, and especially its development, prompted us to embark on a research project to develop design principles for programmes of assessment. We conducted focus group interviews to explore the experiences and views of nine assessment experts concerning good practices and new ideas about theoretical and practical issues in programmes of assessment. The discussion was analysed, mapping all aspects relevant for design onto a framework, which was iteratively adjusted to fit the data until saturation was reached. The overarching framework for designing programmes of assessment consists of six assessment programme dimensions: Goals, Programme in Action, Support, Documenting, Improving and Accounting. The model described in this paper can help to frame programmes of assessment; it not only provides a common language, but also a comprehensive picture of the dimensions to be covered when formulating design principles. It helps identifying areas concerning assessment in which ample research and development has been done. But, more importantly, it also helps to detect underserved areas. A guiding principle in design of assessment programmes is fitness for purpose. High quality assessment can only be defined in terms of its goals

Low-loss, low-confinement GaAs-AlGaAs DQW laser diode with optical trap layer for high-power operation

A low-confinement asymmetric GaAs-AlGaAs double-quantum-well molecular-beam-epitaxy grown laser diode structure with optical trap layer is characterized, The value of the internal absorption coefficient is as low as 1.4 cm-1, while keeping the series resistance at values comparable cm with symmetrical quantum-well gradient index structures in the same material system. Uncoated devices show COD values of 35 mW/µm. If coated, this should scale to about 90 mW/µm. The threshold current density is about 1000 A/cm2 for 2-mm-long devices and a considerable part of it is probably due to recombination in the optical trap layer. Fundamental mode operation is limited to 120-180 mW for 6.5-µm-wide ridge waveguide uncoated devices and to 200-300 mW for 13.5-µm-wide ones, because of thermal waveguiding effects. These values are measured under pulsed conditions, 10 µs/l m

Self-entrustment: how trainees' self-regulated learning supports participation in the workplace

Clinical workplaces offer postgraduate trainees a wealth of opportunities to learn from experience. To promote deliberate and meaningful learning self-regulated learning skills are foundational. We explored trainees’ learning activities related to patient encounters to better understand what aspects of self-regulated learning contribute to trainees’ development, and to explore supervisor’s role herein. We conducted a qualitative non-participant observational study in seven general practices. During two days we observed trainee’s patient encounters, daily debriefing sessions and educational meetings between trainee and supervisor and interviewed them separately afterwards. Data collection and analysis were iterative and inspired by a phenomenological approach. To organise data we used networks, time-ordered matrices and codebooks. Self-regulated learning supported trainees to increasingly perform independently. They engaged in self-regulated learning before, during and after encounters. Trainees’ activities depended on the type of medical problem presented and on patient, trainee and supervisor characteristics. Trainees used their sense of confidence to decide if they could manage the encounter alone or if they should consult their supervisor. They deliberately used feedback on their performance and engaged in reflection. Supervisors appeared vital in trainees’ learning by reassuring trainees, discussing experience, knowledge and professional issues, identifying possible unawareness of incompetence, assessing performance and securing patient safety. Self-confidence, reflection and feedback, and support from the supervisor are important aspects of self-regulated learning in practice. The results reflect how self-regulated learning and self-entrustment promote trainees’ increased participation in the workplace. Securing organized moments of interaction with supervisors is beneficial to trainees’ self-regulated learning

Using a Smartphone App and Coaching Group Sessions to Promote Residents' Reflection in the Workplace

Item does not contain fulltextPROBLEM: Reflecting on workplace-based experiences is necessary for professional development. However, residents need support to raise their awareness of valuable moments for learning and to thoughtfully analyze those learning moments afterwards. APPROACH: From October to December 2012, the authors held a multidisciplinary six-week postgraduate training module focused on general competencies. Residents were randomly assigned to one of four conditions with varying degrees of reflection support; they were offered (1) a smartphone app, (2) coaching group sessions, (3) a combination of both, or (4) neither type of support. The app allowed participants to capture in real time learning moments as a text note, audio recording, picture, or video. Coaching sessions held every two weeks aimed to deepen participants' reflection on captured learning moments. Questionnaire responses and reflection data were compared between conditions to assess the effects of the app and coaching sessions on intensity and frequency of reflection. OUTCOMES: Sixty-four residents participated. App users reflected more often, captured more learning moments, and reported greater learning progress than nonapp users. Participants who attended coaching sessions were more alert to learning moments and pursued more follow-up learning activities to improve on the general competencies. Those who received both types of support were most alert to these learning moments. NEXT STEPS: A simple mobile app for capturing learning moments shows promise as a tool to support workplace-based learning, especially when combined with coaching sessions. Future research should evaluate these tools on a broader scale and in conjunction with residents' and students' personal digital portfolios

Outcome measurement instruments for peripheral vascular malformations and an assessment of the measurement properties: a systematic review

© 2019, The Author(s). Purpose: The Outcome measures for vascular malformation (OVAMA) group reached consensus on the core outcome domains for the core outcome set (COS) for peripheral vascular malformations (venous, lymphatic and arteriovenous malformations). However, it is unclear which instruments should be used to measure these domains. Therefore, our aims were to identify all outcome measurement instruments available for vascular malformations, and to evaluate their measurement properties. Methods: With the first literature search, we identified outcomes and instruments previously used in prospective studies on vascular malformations. A second search yielded studies on measurement properties of patient- and physician-reported instruments that were either developed for vascular malformations, or used in prospective studies. If the latter instruments were not specifically validated for vascular malformations, we performed a third search for studies on measurement properties in clinically similar diseases (vascular or lymphatic diseases and benign tumors). We assessed the methodological quality of these studies following the Consensus-based Standards for the selection of health Measurement Instruments methodology, and evaluated the quality of the measurement properties. Results: The first search yielded 27 studies, none using disease-specific instruments. The second and third search included 22 development and/or validation studies, concerning six instruments. Only the Lymphatic Malformation Function Instrument was developed specifically for vascular malformations. Other instruments were generic QoL instruments developed and/or partly validated for clinically similar diseases. Conclusions: Additional research on measurement properties is needed to assess which instruments may be included in the COS. This review informs the instrument selection and/or the development of new instruments. Systematic review registration: PROSPERO, 42017056242

Effective low-dose sirolimus regimen for kaposiform haemangioendothelioma with Kasabach-Merritt phenomenon in young infants

Aims Management of kaposiform haemangioendotheliomas (KHE) with Kasabach-Merritt phenomenon is challenging in young infants who are subjected to developmental pharmacokinetic changes. Sirolimus, sometimes combined with corticosteroids, can be used as an effective treatment of KHE. Simultaneously, toxicities such as interstitial pneumonitis related to the use of sirolimus may be fatal. As infants have a very low CYP3-enzyme expression at birth, which rises during ageing, we hypothesize that a reduced metabolization of sirolimus might lead to high sirolimus serum levels and low dose may be sufficient without the side effects. Methods A case series of 5 infants with kaposiform haemangioendothelioma with Kasabach-Merritt phenomenon was analysed retrospectively. All infants were treated with sirolimus 0.2 mg/m(2) every 24 or 48 hours according to their age. Prednisone was added to the therapy for additional effect in 4 patients. Results In all patients, low dose of sirolimus led to therapeutic sirolimus levels (4-6 ng/mL). All infants (aged 4 days-7 months) had a complete haematological response, without serious adverse events. In all patients, the Kasabach-Merritt phenomenon resolved, the coagulation profile normalized and tumour size reduction was seen. Conclusion Low-dose sirolimus treatment is safe for infants with kaposiform haemangioendothelioma and Kasabach-Merritt phenomenon. It is essential to realize that during the first months of life, metabolism is still developing and enzymes necessary to metabolise drugs like sirolimus still have to mature. To avoid toxic levels, the sirolimus dosage should be based on age and the associated pharmacological developments