Absence of quantum-confined Stark effect in GaN quantum disks embedded in (Al,Ga)N nanowires grown by molecular beam epitaxy

Several of the key issues of planar (Al,Ga)N-based deep-ultraviolet light emitting diodes could potentially be overcome by utilizing nanowire heterostructures, exhibiting high structural perfection and improved light extraction. Here, we study the spontaneous emission of GaN/(Al,Ga)N nanowire ensembles grown on Si(111) by plasma-assisted molecular beam epitaxy. The nanowires contain single GaN quantum disks embedded in long (Al,Ga)N nanowire segments essential for efficient light extraction. These quantum disks are found to exhibit intense emission at unexpectedly high energies, namely, significantly above the GaN bandgap, and almost independent of the disk thickness. An in-depth investigation of the actual structure and composition of the nanowires reveals a spontaneously formed Al gradient both along and across the nanowire, resulting in a complex core/shell structure with an Al deficient core and an Al rich shell with continuously varying Al content along the entire length of the (Al,Ga)N segment. This compositional change along the nanowire growth axis induces a polarization doping of the shell that results in a degenerate electron gas in the disk, thus screening the built-in electric fields. The high carrier density not only results in the unexpectedly high transition energies, but also in radiative lifetimes depending only weakly on temperature, leading to a comparatively high internal quantum efficiency of the GaN quantum disks up to room temperature.Comment: This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Nano Letters (2019), copyright (C) American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.nanolett.9b01521, the supporting information is available (free of charge) under the same lin

Efficacy and efficiency of a new therapeutic approach based on activity-oriented proprioceptive antiedema therapy (TAPA) for edema reduction and improved occupational performance in the rehabilitation of breast cancer-related arm lymphedema in women: a controlled, randomized clinical trial

Background: Breast cancer (BC) is a major public health issue. More than one out of five women treated for breast cancer will develop lymphedema in an upper extremity. Current evidence advocates transdisciplinary oncological rehabilitation. Therefore, research in this area is necessary since limited consensus having been reached with regard to the basic essential components of this rehabilitation. Consensus has, however, been reached on the use of decongestive lymphedema therapy (DLT), but due to a lack of tests, the necessary dosages are unknown and its level is moderately strong. This study attempts to verify both the efficacy of activity-oriented proprioceptive antiedema therapy (TAPA), as compared to conventional treatments such as DLT or Complex Physical Therapy (CPT), as well as its efficiency in terms of cost-effectiveness, for patients affected by breast cancer-related arm lymphedema. Methods: Controlled, randomized clinical trial with dual stratification, two parallel arms, longitudinal and single blind. 64 women with breast cancer-related arm lymphedema will take part in the study. The experimental group intervention will be the same for stage I and II, and will consist of neuro-dynamic exercises oriented to the activity, proprioceptive neuromuscular facilitation activities and proprioceptive anti-edema bandaging. The control group intervention, depending on the stage, will consist of preventive measures, skin care and exercise-prescribed training in the lymphedema workshop as well as compression garments (Stage I) or conservative Complex Decongestive Therapy treatment (skin care, multi-layer bandaging, manual lymphatic drainage and massage therapy) (Stage II). Results: Sociodemographic and clinical variables will be collected for the measurement of edema volume and ADL performance. Statistical analysis will be performed on intent to treat. Discussion: It has been recommended that patient training be added to DLT, as well as a re-designing of patient lifestyles and the promotion of health-related aspects. In addition, clinical trials should be undertaken to assess neural mobilization techniques and proprioceptive neuromuscular facilitation should be included in the therapy. Cohesive bandaging will also be performed as an early form of pressotherapy. The proposed study combines all of these aspects in order to increased comfort and promote the participation of individuals with lymphedema in everyday situations. Limitations: The authors have proposed the assessment of the experimental treatment for stages I and II. One possible limitation is the lack of awareness of whether or not this treatment would be effective for other stages as well as the concern for proper hand cleansing during use of bandages, given the current COVID-19 pandemic situation. Trial registration: This trial was registered in ClinicalTrials.gov (NCT03762044). Date of registration: 23 November 2018. Prospectively Registered