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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.

Between 1774 and 1781, Eise Eisinga built an orrery in his house in Franeker. This instrument was and is commonly referred to as a planetarium, although it also gives information about the sun, the moon and the main constellations. I use the term ‘instrument’ for the machinery above the ‘planetarium room’ and the boxbed together with the dials on the ceiling and the wall containing the box-bed (bedsteewand). I use the term ‘Planetarium’ for the institution, that is the building with everything in it. The machinery, the ceiling, and the bedsteewand have been nominated for UNESCO world heritage status this year. The aim of this article is to discuss the authenticity of the Planetarium: which parts are authentic – that is, from the time of Eisinga – which have been altered, and how were any alterations supervised? The article concentrates on the period around 1900, when the conservation of monuments had just been institutionalized, but the general principle of preferring ‘preservation over alteration’ had not yet been widely accepted. The primary sources are the annual reports on the state of maintenance by government architect Jacobus van Lokhorst. Eisinga had sold the Planetarium to the national government in 1826. In order to save money, the government gave it to the municipality of Franeker in 1859. When it was suspected that the municipality was not meeting the first condition of the agreement – to maintain the instrument at all times – Van Lokhorst was tasked with the supervision of the Planetarium by the Minister of the Interior in 1882. We know that the instrument was repaired a couple of times, but the exact nature of the alterations is unknown, because Van Lokhorst barely mentions them in his reports. He had to leave the supervision of the instrument to the caretaker and a clockmaker, because he was out of his depth. The only parts of the ‘planetarium room’ that remained authentic around 1900 are the ceiling and the bedsteewand. After the instrument had come to a standstill several times, a stove had to be installed to decrease the humidity in the room. That is why in 1890 the windows were replaced to make room for a chimney. The rest of the room was turned into a period room on the advice of Van Lokhorst and with permission of the Minister of the Interior: the walls were whitewashed and, a year later, the floor was tiled. The tile wainscoting dates from 1895. The conclusion is that the authenticity of the Planetarium decreased around 1900. This should not affect the UNESCO nomination. Repairs to the machinery were only to be expected, and the ceiling and the bedsteewand appear to be authentic. However, a world heritage site attracts more visitors, all of whom have to be facilitated. How will this affect the authenticity of the Planetarium in the future?

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.

In Panorama van de wetenschap vertellen specialisten en kenners verhalen over wonderlijke, vernuftige en zeldzame museumstukken. Deze verhalen laten zien hoe onderzoekers gefascineerd werden door de wereld om hen heen en hoe ze probeerden om deze beter te begrijpen. Zo ontstaat een brede blik op de ontwikkeling van de wetenschap, vanaf de vroege zeventiende eeuw tot Nobelprijswinnend onderzoek van vandaag.

Supplementary Material for Body Image and Cosmesis After Percutaneous Transforaminal Endoscopic Discectomy Versus Conventional Open Microdiscectomy for Sciatica Caused by Lumbar Disc Herniation: Results of a Randomized Controlled Trial by Pravesh S. Gadjradj, Paul R. Depauw, Pieter J. Schutte, Arnold V. Vreeling, and Biswadjiet S. Harhangi in Global Spine Journal.

In Panorama van de wetenschap vertellen specialisten en kenners verhalen over wonderlijke, vernuftige en zeldzame museumstukken. Deze verhalen laten zien hoe onderzoekers gefascineerd werden door de wereld om hen heen en hoe ze probeerden om deze beter te begrijpen. Zo ontstaat een brede blik op de ontwikkeling van de wetenschap, vanaf de vroege zeventiende eeuw tot Nobelprijswinnend onderzoek van vandaag.

In the context of Article 3.1 of the compatibility law 2016 (Comptabiliteitswet) (CW 2016), which aims to bring about more scientific underpinning of policy, the House of Representatives in 2019 examined the extent to which policy proposals address the efficiency and effectiveness of the policy instruments to be deployed (Sneller & Snels, 2019). They concluded that while they often address how these instruments should contribute to the objective, they often do not address to what extent. Making such statements about efficiency and effectiveness requires an understanding of scientific evidence. As a result, the Netherlands Environmental Assessment Agency (PBL) anticipates that they will receive more frequent questions from the government about what science says about the effectiveness of proposed policies. PBL already has a strong scientific orientation in its work and recognizes the great importance of a request for scientific foundation. But is also foresees that answering this type of question about scientific evidence for policy proposals can be difficult in practice. This is due to the short period in which these questions must generally be answered on the one hand and the time required for (systematic) literature review on the other. Conducting a (systematic) literature search using artificial intelligence (AI) could offer a solution to this problem and that is what this report is about. When using AI, the literature search is supported by a so-called learning algorithm, which learns as the process progresses to better and better assess what is relevant literature for the researcher. However, little experience has been gained with the use of such software in policy-oriented research. PBL therefore asked the UG to investigate how the open-source AI software ASReview could offer a solution in efficiently meeting the demand for scientific insights from the government. At PBL's request, the UG researched three substantive questions around the effectiveness of policy instruments for sustainable agriculture and used these to test the process of the AI supported literature review. In this research, the UG worked with a combination of AI-supported literature screening and sounding boards of academics who fed the search at the beginning and interpreted the results substantively at the end. Such a sounding board enables the distillation of substantive lessons in a relatively short time. The findings are: 1. It is possible to conduct a quick and good systematic literature search by combining AI-supported literature search with a sounding board of scientific experts. The search for scientific insights that could potentially provide substantiation yielded a database of 40.000 potentially relevant papers, from which a diverse set of 100 relevant papers were selected using AI. Using the sounding board of experts, an even smaller set of 12 papers was created from this list that were deemed most urgent for policymakers to study. 2. Because the AI software ASReview puts content first and hides reputation of authors and journals during screening, objectivity and breadth is stimulated; 3. However, ASReview does present other challenges that, if not taken into account, can compromise the objectivity of research in other ways; i) One of the main risks of using ASReview is what we call ‘trap formation’, especially when there is a short time frame for screening. This means that you end up on a particular 'track' of articles on a particular (sub)topic, which means that other also relevant articles are not found. The broader the query and the less time, the more this poses a risk to the efficiency and reliability of the screening. By using certain settings for the screening, this can be taken into account to a certain extent. ii) The amount of efficiency gains that can be achieved with ASReview depends on the breadth and multidisciplinarity of the research question. The topic of sustainable agriculture has many facets, both in terms of instruments and outcomes. This makes it more difficult for the program to quickly learn what is most relevant, so screening will take more time; iii) AI is not a fully automated process. Use of the program requires skill from the researcher to drive the algorithm and expert knowledge to start the process and expert knowledge to interpret the results. 4. The content of this research has resulted in two sets of scientific articles: a Top 100 and a Top 12. 5. The first end result of the Systematic Review is a list (Top 100) of relevant articles ranked by their "scientific recognition." Here, because of the requirement for speed in the process, scientific recognition is simply operationalized as a combination of the number of citations of the article per year and the impact factor of the journal (as a measure of the seriousness of the blind review process) in which they were published. While there are caveats to this method of ranking, it does provide a way to make a large amount of knowledge manageable within a relatively short period of time, and in doing so, gives policymakers and researchers a foothold that they can study "the most important first''. 6. The second end result is a selection from the top 100 by the scientific experts: which ones are most important for policy? The six multi-disciplinary scholars each selected three papers that they felt were most important for policymakers and researchers to take to task: combined, this yielded a set of 12 articles. The Top 12 is a manageable set of articles that was selected quickly, and can be studied in content in a short period of time while being largely systematic. 7. In conclusion. What does the process tested here offer compared to what we might call "the standard quick search for scientific evidence" of a PBL staff member? This search often consists of manually consulting Google Scholar and/or individually contacting a scientific expert. Compared to manual searches via Scholar, searching the literature with ASReview offers the opportunity to systematically review a vast amount of studies for relevance. After each selection by the researcher, the entire database is reordered. Ultimately, it has been shown, this leads to a greater diversity of studies than a manual search process. Compared to contacting experts individually, the added value of utilizing a group of experts in this study is not only their diversity of expertise, but also that they all reflect on the same scientific dataset and choose from it (quickly and rationally) the most relevant ones for policy. This is a much more systematic process than asking for their scientific views separately.