RESUMO
We demonstrate a mechanism of solid-phase crystallization (SPC) enabled by nanoscale cavities formed at the interface between an hydrogenated amorphous silicon film and embedded 30 to 40 nm Si nanocrystals. The nanocavities, 10 to 25 nm across, have the unique property of an internal surface that is part amorphous and part crystalline, enabling capillarity-driven diffusion from the amorphous to the crystalline domain. The nanocavities propagate rapidly through the amorphous phase, up to five times faster than the SPC growth rate, while "pulling behind" a crystalline tail. Using transmission electron microscopy it is shown that twin boundaries exposed on the crystalline surface accelerate crystal growth and influence the direction of nanocavity propagation.
Assuntos
Nanopartículas/química , Nanotecnologia/métodos , Silício/química , Cristalização , Microscopia Eletrônica de Transmissão , Nanoestruturas/química , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
CONTEXT: Pain is a primary reason individuals attend an Emergency Department (ED), and its management is a concern. OBJECTIVES: Change in symptoms and physiologic variables at 3 time points pre-post a ten-minute St. John Ambulance therapy dog team visit compared to no visit in ED patients who experienced pain. DESIGN, SETTING AND PARTICIPANTS: Using a controlled clinical trial design, pain, anxiety, depression and well-being were measured with the Edmonton Symptom Assessment System (revised version) (ESAS-r) 11-point rating scales before, immediately after, and 20 minutes post- therapy dog team visit with Royal University Hospital ED patients participating in the study (n = 97). Blood pressure and heart rate were recorded at the time points. Control data was gathered twice (30 minutes apart) for comparison (n = 101). There were no group differences in age, gender or ethnicity among the control and intervention groups (respectively mean age 59.5/57.2, ethnicity 77.2% Caucasian/87.6%, female 43.6% /39.2%, male 56.4%/60.8%,). INTERVENTION: 10 minute therapy dog team visit in addition to usual care. MAIN OUTCOME MEASURES: Change in reported pain from pre and post therapy dog team visit and comparison with a control group. RESULTS: A two-way ANOVA was conducted to compare group effects. Significant pre- post-intervention differences were noted in pain for the intervention (mean changeint. = -0.9, SD = 2.05, p = .004, 95% confidence interval [CI] = [0.42, 1.32], ηp2 = 04) but not the control group. Anxiety (mean changeint. = -1.13, SD = 2.80, p = .005, 95% CI = [0.56, 1.64], ηp2 = .04), depression (mean changeint. = -0.72, SD = 1.71, p = .002, 95% CI = [0.39, 1.11], ηp2 = .047), and well-being ratings (mean changeint. = -0.87, SD = 1.84, p < .001, 95% CI = [0.49, 1.25], ηp2 = .07) similarly improved for the intervention group only. There were no pre-post intervention differences in blood pressure or heart rate for either group. Strong responders to the intervention (i.e. >50% reduction) were observed for pain (43%), anxiety (48%), depression (46%), and well-being (41%). CONCLUSIONS: Clinically significant changes in pain as well as significant changes in anxiety, depression and well-being were observed in the therapy dog intervention compared to control. The findings of this novel study contribute important knowledge towards the potential value of ED therapy dogs to affect patients' experience of pain, and related measures of anxiety, depression and well-being. TRIAL REGISTRATION: This controlled clinical trial is registered with ClinicalTrials.gov, registration number NCT04727749.