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Two types of dedicated Tristructural isotropic (TRISO) nuclear fuel particles, PyC-1 (Kernel/Buffer/PyC) and PyC-2 (Kernel/Buffer/SiC/PyC) from PYCASSO (Pyrocarbon irradiation for creep and swelling/shrinkage of objects) neutron irradiation experiments, were studied. For unirradiated particles, crushing experiments using a unique hot cell, combined with in situ X-ray computed micro-tomography (XCT) imaging, were conducted at room temperature (RT) and at 1000 °C. Although the SiC layer on the particles is presumed to provide ‘mechanical stability’ to the TRISO particles, results showed a remarkable reduction (~45%) in the crushing strength of the PyC-2 particles at 1000 °C compared to RT. The fracture patterns of the two types of particles, both at the contact zone and on subsequent propagation, differ significantly at RT and 1000 °C. Further, irradiated particles (irradiation temperature: 1000 ± 20 °C; irradiation doses: 1.08–1.23 dpa and 1.49–1.51 dpa) were imaged by XCT; 250 PyC-1 particles and 223 PyC-2 particles were studied in total and the change in radius/layer thickness in each type was examined. It was found that the buffer densification was lower in PyC-1 particles compared to PyC-2 particles, and the PyC layer shrank in the PyC-I particles, whereas it expanded in PyC-2. Results are discussed in terms of how the residual stresses can impact the high-temperature and post-irradiation behavior of these particles.

Two types of dedicated Tristructural isotropic (TRISO) nuclear fuel particles, PyC-1 (Kernel/Buffer/PyC) and PyC-2 (Kernel/Buffer/SiC/PyC) from PYCASSO (Pyrocarbon irradiation for creep and swelling/shrinkage of objects) neutron irradiation experiments, were studied. For unirradiated particles, crushing experiments using a unique hot cell, combined with in situ X-ray computed micro-tomography (XCT) imaging, were conducted at room temperature (RT) and at 1000 °C. Although the SiC layer on the particles is presumed to provide ‘mechanical stability’ to the TRISO particles, results showed a remarkable reduction (~45%) in the crushing strength of the PyC-2 particles at 1000 °C compared to RT. The fracture patterns of the two types of particles, both at the contact zone and on subsequent propagation, differ significantly at RT and 1000 °C. Further, irradiated particles (irradiation temperature: 1000 ± 20 °C; irradiation doses: 1.08–1.23 dpa and 1.49–1.51 dpa) were imaged by XCT; 250 PyC-1 particles and 223 PyC-2 particles were studied in total and the change in radius/layer thickness in each type was examined. It was found that the buffer densification was lower in PyC-1 particles compared to PyC-2 particles, and the PyC layer shrank in the PyC-I particles, whereas it expanded in PyC-2. Results are discussed in terms of how the residual stresses can impact the high-temperature and post-irradiation behavior of these particles.

Coated fuel particles, most commonly tri-structural isotropic (TRISO), are intended for application in several designs of advanced nuclear reactors. A complete understanding of the residual stresses and local properties of these particles through their entire lifecycle is required to inform fuel element manufacturing, reactor operation, accident scenarios, and reprocessing. However, there is very little experimental data available in the literature on the magnitude of residual stresses in the individual coating layers of these particles. This work applies ring-core focussed ion beam milling combined with digital image correlation analysis (FIB-DIC) to cross-sections of TRISO and pyrolytic carbon coatings in surrogate coated fuel particles to evaluate the residual stresses. Tensile residual hoop stresses are identified in both pyrolytic carbon layers, while silicon carbide experiences a compressive residual hoop stress. Note that these residual stresses, which were not accounted for in the models reported in open literature, have magnitudes comparable to the stresses predicted to arise in real fuel particles during service. A 2D linear-elastic continuum-based finite element analysis has been conducted to investigate the stress relaxation phenomena caused by sectioning stressed coatings on spherical particles. The FIB-DIC method established here is independent of radiation defects and can be applied to irradiated TRISO particles to retrieve first-hand information regarding the residual stress evolution during service.

Objective Full-endoscopic spine surgery is gaining interest as a less-invasive alternative to treat sciatica caused by a lumbar disc herniation. Concerns, however, exist with the learning curve as percutaneous transforaminal endoscopic discectomy (PTED) appears to be more difficult to be performed compared to other techniques. In this study, the clinical outcomes during and after the learning curve are presented of 3 surgeons naïve to PTED. Methods In the first phase of a randomized controlled, noninferiority trial comparing PTED with microdiscectomy, 3 surgeons were trained in the PTED-procedure by a senior surgeon. After performing up to 20 cases under supervision, they started performing PTED on their own. Results of the early cases were compared to the later cases (>20). Furthermore, complications and reoperations were compared. Finally, differences in clinical outcomes between surgeons were compared. Results At 12 months of follow-up, 87% of the patients had follow-up data available. In general, there were no significant differences in patient-reported outcomes between the early and later PTED cases. Furthermore, outcomes of the early PTED cases were comparable to the outcomes of microdiscectomy, while the later PTED cases had small, but more favorable outcomes compared to microdiscectomy. Two learning curve surgeons had substantially higher rates of reoperations within 1 year, compared to the senior surgeon or the microdiscectomy group. Duration of surgery was also longer for all learning curve surgeons. Finally, when comparing clinical outcomes of patients undergoing PTED versus microdiscectomy, there appears to be some statistically significant differences in outcomes compared between the senior and 3 learning curve surgeons. Conclusion PTED appears to be safe to be adopted by surgeons naïve to the procedure when they are initially supervised by an experienced senior surgeon. Duration of surgery and risk of repeated surgery are increased during the learning curve, but patient-reported outcomes of the early PTED cases are similar to the outcomes of later PTED cases, and similar to the outcomes of microdiscectomy cases. This study underlines the need for an experienced mentor for surgeons to safely adopt PTED.

Objective Percutaneous transforaminal endoscopic discectomy (PTED) is gaining popularity by both surgeons and patients as a less invasive treatment option for sciatica. Concerns, however, exist for its learning curve. No previous study has assessed the learning process of PTED. Hereby we present the learning process of 3 surgeons learning PTED. Methods This analysis was conducted alongside a multicenter randomized controlled trial. After attending a cadaveric workshop, 3 spine-dedicated surgeons started performing PTED, initially under the supervision of a senior surgeon. After each 5 cases, and up to case 20, the learning process was evaluated using the validated questionnaires (objective structured assessment of technical skills [OSATS], global operative assessment of laparoscopic skills [GOALS]) and a 10-step checklist specifically developed for PTED. Results In total, 3 learning curve surgeons performed a total of 161 cases. Based on self-assessment, surgeons improved mostly in the domains “time and motion,” “respect for tissue,” and “knowledge and handling of instruments.” Learning curve surgeons were more able to detect differences in performances on the OSATS than the senior surgeon. Based on the GOALS, the biggest improvements could be seen in “depth-perception” and “autonomy.” Based on the 10-item specific checklist, all surgeons performed all 10 steps by case 10, while only 1 surgeon performed all steps adequately by case 15. Conclusion Based on these study results, PTED appears to be successfully adopted stepwise by 3 spine-dedicated surgeons. From 15 cases on, most steps are performed adequately. However, more cases might be necessary to achieve good clinical results. Validated tools are needed to determine the cutoff when a surgeon should be able to perform PTED independently.

Abstract Background Medical specialists experience high levels of stress. This has an impact on their well-being, but also on quality of their leadership. In the current mixed method study, the feasibility and effectiveness of a course Mindful Leadership on burnout, well-being and leadership skills of medical specialists were evaluated. Methods This is a non-randomized controlled pre-post evaluation using self-report questionnaires administered at 3 months before (control period), start and end of the training (intervention period). Burn-out symptoms, well-being and leadership skills were assessed with self-report questionnaires. Semi-structured interviews were used to qualitatively evaluate barriers and facilitators for completion of the course. Results From September 2014 to June 2016, 52 medical specialists participated in the study. Of these, 48 (92%) completed the course. Compared to the control period, the intervention period resulted in greater reductions of depersonalization (mean difference = − 1.2, p = 0.06), worry (mean difference = − 4.3, p = 0.04) and negative work-home interference (mean difference = − 0.2, p = 0.03), and greater improvements of mindfulness (mean difference = 0.5, p = 0.04), life satisfaction (mean difference = 0.4, p = 0.01) and self-reported ethical leadership (mean difference = 0.1, p = 0.02). Effect sizes were generally small to medium (0.3 to 0.6) and large for life satisfaction (0.8). Appreciation of course elements was a major facilitator and the difficulty of finding time a major barrier for participating. Conclusions A ‘Mindful Leadership’ course was feasible and not only effective in reducing burnout symptoms and improving well-being, but also appeared to have potential for improving leadership skills. Mindful leadership courses could be a valuable part of ongoing professional development programs for medical specialists.

Objectives Medical leaders are facing leadership challenges that ask for a leadership style that takes care of both themselves and their coworkers. Mindfulness may support this leadership style. We explored how a ‘Mindful leadership for medical specialists’ course affected medical specialists’ leadership.Design We conducted a qualitative study based on in-depth interviews. The grounded theory method was used to analyse the data.Setting A university medical centre in the Netherlands.Participants Seventeen medical specialists (six male) with an average age of 51 years (ranging from 40 to 66 years).Interventions The mindful leadership course consisted of 10-weekly 5-hour sessions that focused on cultivating mindfulness and compassion. In addition, sessions included didactic and interactional teaching about leadership theories.Results Four categories emerged from the data: (A) Self - Attitude: psychological attitude towards self, (B) Self - Behaviour: behaviour towards self, (C) Other - Attitude: psychological attitude towards others, and (D) Other - Behaviour: behaviour towards others. Themes were defined within these categories: awareness of self, open mind, insight and appreciation of self (A), emotional and cognitive self-regulation, letting go of unhelpful behaviour and developing helpful behaviour (B), differences in attitude to others such as awareness of (impact on) others, keeping an open mind about others, allowing difficult emotions associated with others, appreciating of others (C), and communicating more effectively, providing direction, empowering and caring for others (D).Conclusions The results help us understand the core elements of mindful leadership, both with respect to one’s psychological attitude and behaviour towards oneself and others. More research on mindful leadership and the effects on self and others is needed. Mindful leadership courses could be a valuable part of clinical training and might contribute to more sustainable healthcare organisations.

Study Design: Randomized controlled trial Objective: Percutaneous transforaminal endoscopic discectomy (PTED) was introduced as a less invasive procedure to treat sciatica. Even though the PTED has a small scar size, it is unknown if PTED also leads to better scar-related patient-reported outcomes. Therefore, we aimed to compare scar-related outcomes between patients undergoing PTED vs open microdiscectomy. Methods: Patients with at least 6 weeks of radiating leg pain were randomized in a 1:1 ratio to PTED or open microdiscectomy. Scar-related patient-reported outcomes were measured using the Body Image Score (BIS), Cosmesis Scale (CS) and a 0-10 numeric rating scale (NRS) on scar esthetic. Results: Of the 530 included patients, 286 patients underwent PTED and 244 underwent open microdiscectomy as allocated. At 12 months of follow-up, 95% of the patients had data available. At 12 months, the BIS was 6.2 ± 1.7 in the PTED-group and 6.6 ± 1.9 in the open microdiscectomy group (between-group difference.4, 95% CI.2 to.7). CS was 21.3 ± 3.0 in the PTED-group and 18.6 ± 3.4 in the open microdiscectomy group (between-group difference −2.7, 95% CI −3.1 to −2.3). Average NRS for scar esthetic was 9.2 ± 1.3 and 7.8 ± 1.6 in the PTED and open microdiscectomy groups, respectively (between-group difference −1.4, 95% CI −1.6 to −1.2) Conclusions: PTED leads to a higher self-rated scar esthetic as compared to open microdiscectomy, while self-reported body image seems to be comparable between both groups. Therefore, from an esthetic point, PTED seems to be the preferred technique to treat sciatica. [ABSTRACT FROM AUTHOR]

A submillimeter heterodyne spectrometer with a superconducting local oscillator is described and discussed.

Objective: Full-endoscopic spine surgery is gaining interest as a less-invasive alternative to treat sciatica caused by a lumbar disc herniation. Concerns, however, exist with the learning curve as percutaneous transforaminal endoscopic discectomy (PTED) appears to be more difficult to be performed compared to other techniques. In this study, the clinical outcomes during and after the learning curve are presented of 3 surgeons naïve to PTED. Methods: In the first phase of a randomized controlled, noninferiority trial comparing PTED with microdiscectomy, 3 surgeons were trained in the PTED-procedure by a senior surgeon. After performing up to 20 cases under supervision, they started performing PTED on their own. Results of the early cases were compared to the later cases (>20). Furthermore, complications and reoperations were compared. Finally, differences in clinical outcomes between surgeons were compared. Results: At 12 months of follow-up, 87% of the patients had follow-up data available. In general, there were no significant differences in patient-reported outcomes between the early and later PTED cases. Furthermore, outcomes of the early PTED cases were comparable to the outcomes of microdiscectomy, while the later PTED cases had small, but more favorable outcomes compared to microdiscectomy. Two learning curve surgeons had substantially higher rates of reoperations within 1 year, compared to the senior surgeon or the microdiscectomy group. Duration of surgery was also longer for all learning curve surgeons. Finally, when comparing clinical outcomes of patients undergoing PTED versus microdiscectomy, there appears to be some statistically significant differences in outcomes compared between the senior and 3 learning curve surgeons. Conclusion: PTED appears to be safe to be adopted by surgeons naïve to the procedure when they are initially supervised by an experienced senior surgeon. Duration of surgery and risk of repeated surgery are increased during the learning curve, but patient-reported outcomes of the early PTED cases are similar to the outcomes of later PTED cases, and similar to the outcomes of microdiscectomy cases. This study underlines the need for an experienced mentor for surgeons to safely adopt PTED. [ABSTRACT FROM AUTHOR]

Objective: Percutaneous transforaminal endoscopic discectomy (PTED) is gaining popularity by both surgeons and patients as a less invasive treatment option for sciatica. Concerns, however, exist for its learning curve. No previous study has assessed the learning process of PTED. Hereby we present the learning process of 3 surgeons learning PTED. Methods: This analysis was conducted alongside a multicenter randomized controlled trial. After attending a cadaveric workshop, 3 spine-dedicated surgeons started performing PTED, initially under the supervision of a senior surgeon. After each 5 cases, and up to case 20, the learning process was evaluated using the validated questionnaires (objective structured assessment of technical skills [OSATS], global operative assessment of laparoscopic skills [GOALS]) and a 10-step checklist specifically developed for PTED. Results: In total, 3 learning curve surgeons performed a total of 161 cases. Based on selfassessment, surgeons improved mostly in the domains "time and motion," "respect for tissue," and "knowledge and handling of instruments." Learning curve surgeons were more able to detect differences in performances on the OSATS than the senior surgeon. Based on the GOALS, the biggest improvements could be seen in "depth-perception" and "autonomy." Based on the 10-item specific checklist, all surgeons performed all 10 steps by case 10, while only 1 surgeon performed all steps adequately by case 15. Conclusion: Based on these study results, PTED appears to be successfully adopted stepwise by 3 spine-dedicated surgeons. From 15 cases on, most steps are performed adequately. However, more cases might be necessary to achieve good clinical results. Validated tools are needed to determine the cutoff when a surgeon should be able to perform PTED independently. [ABSTRACT FROM AUTHOR]