Construction of a setup for Ultrafast Electron Diffraction:First experiments on bimetallic foils and Heusler alloys

Tijdsopgeloste elektronendiffractie maakt het mogelijk om filmpjes te maken van atomaire bewegingen op een tijdsschaal van 100 femtosecondes – een femtoseconde is een duizendste van een miljoenste van een miljoenste van een seconde. Dit is precies de tijdsschaal waarop bindingen tussen atomen worden gevormd en verbroken. Door deze techniek kunnen we fase-overgangen (zoals het smelten van een metaal) volgen terwijl ze plaatsvinden, terwijl dat met andere technieken alleen voor en na de fase-overgang mogelijk is. Dit proefschrift beschrijft de constructie van een experimentele opstelling voor deze techniek in het Zernike Institute for Advanced Materials. Deze opstelling is uniek omdat zij uitermate geschikt is voor het bestuderen van dunne lagen van materialen, precies waarin de onderzoeksgroep waarin het onderzoek heeft plaatsgevonden, gespecialiseerd is. De eerste twee experimenten waar de opstelling voor gebruikt is, zijn ook beschreven in het proefschrift. In het eerste experiment wordt gekeken hoe de energieoverdracht plaatsvindt wanneer een folie bestaande uit een laagje chroom (5 nanometer dik) en een laagje goud (40 nanometer dik) wordt beschenen met een kort pulsje laserlicht. Het blijkt dat het grensvlak tussen de twee metalen hierbij een cruciale rol speelt. Het tweede experiment betreft een zogenaamde Heuslerlegering, een materiaal waarmee bijvoorbeeld nanopincetten kunnen worden gemaakt. Wij zijn de eersten die een overgang tussen twee toestanden van dit materiaal op deze tijdsschaal hebben bestudeerd. Voor de toekomst zijn er plannen om naar supergeleiders te kijken, omdat meer kennis over het hoe en waarom van deze materialen veel energieverlies overbodig zou kunnen maken.Using Ultrafast Electron Diffraction movies can be produced of atomic motion at a 100 femtosecond time resolution – a femtosecond is a thousandth of a millionth of a millionth of a second. This is exactly the time scale at which atomic bonds are being formed and broken. Using this technique phase transitions (like melting a metal) can be followed while they take place, rather then only studying the material before and after the phase transition.This thesis describes the construction of a experimental setup for this technique at the Zernike Institute for Advanced Materials. This setup is unique because it is very suitable for the study of thin films, exactly the research area of the group in which the research was performed. The two first experiments conducted at this setup are also discussed in this thesis. The goal of the first experiment was to study the heat transfer in a bimetallic foil of chromium (5 nanometer) and gold (40 nanometer) after excitation with a short pulse of laser light. It turned out that the interface between the two metals plays a crucial role in this process. In the second experiment we studied a so-called Heusler alloy, a material which is very suitable for applications like nanotweezers. We were the first to study the transition between two states of this material at this time scale. Future experiments are planned on super conductors, because more knowledge about the phase transition in these materials could help in reducing lots of energy losses

Short communication: a hierarchy of items within Eysenck’s EPI

Based on the recent finding of a hierarchical scale for Neuroticism in the NEO-Five Factor Inventory, two further personality inventories: the Eysenck Personality Inventory and Goldberg’s International Personality Item Pool were analysed using the Mokken Scaling Procedure for hierarchical scales. Items from two dimensions of the Eysenck Personality Inventory: Neuroticism and Extraversion produced hierarchical scales of 12 and five items, respectively. The Neuroticism items ran from items expressing mild to more extreme worry and the Extraversion items ran from mild sociability to more extreme ‘showing off’. The utility of hierarchical scales in personality measurement is discussed in terms of furthering theoretical understanding of personality and also practical application. In addition, the reasons why only one of these scales should produce hierarchical sets of items is discussed

Awareness about developmental coordination disorder

Data availability statement: The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.The present paper is designed to promote awareness of DCD outside the academic world. With a prevalence of 5–6% it is one of the most common disorders of child development. It is therefore surprising that so little is known about it among professionals in child healthcare and education. Parents have expressed frustration about this lack of awareness, including the general public. The general aim of this paper was to describe those critical aspects of DCD that will promote awareness.Research Foundation Flanders (FWO: 1232221N). This research of PW is supported by the Czech Science Foundation (GACR EXPRO scheme: 21-15728X). The authors are part of the “DCD Big Ideas Group” consisting of 25 key researchers in the field of DCD (from early-career to established) working to develop a clear vision for the future of research on DCD. BS and HB were supported by a grant (TRIAL) from the Dutch Research Council (NWO), grant number NWA.1160.18.249

Electrical control of uniformity in quantum dot devices

Highly uniform quantum systems are essential for the practical implementation of scalable quantum processors. While quantum dot spin qubits based on semiconductor technology are a promising platform for large-scale quantum computing, their small size makes them particularly sensitive to their local environment. Here, we present a method to electrically obtain a high degree of uniformity in the intrinsic potential landscape using hysteretic shifts of the gate voltage characteristics. We demonstrate the tuning of pinch-off voltages in quantum dot devices over hundreds of millivolts that then remain stable at least for hours. Applying our method, we homogenize the pinch-off voltages of the plunger gates in a linear array for four quantum dots reducing the spread in pinch-off voltage by one order of magnitude. This work provides a new tool for the tuning of quantum dot devices and offers new perspectives for the implementation of scalable spin qubit arrays

Kidney disease in adults with Prader-Willi syndrome:international cohort study and systematic literature review

BACKGROUND: Prader-Willi syndrome (PWS) is a rare, complex, genetic disorder characterized by hyperphagia, hypotonia, delayed psychomotor development, low muscle mass and hypothalamic dysfunction. Adults with PWS often have obesity, hypertension and type 2 diabetes mellitus (DM2), known risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD). Early symptoms of CVD and CKD may be masked by intellectual disability and inability to express physical complaints. Furthermore, kidney diseases are often asymptomatic. Therefore, renal and cardiovascular disease might be missed in patients with PWS. Microalbuminuria is an early sign of microvascular damage in the kidneys and other vascular beds. Therefore, we screened our adult PWS cohort for the presence of elevated urinary albumin and (micro)albuminuria.METHODS: We retrospectively collected anthropometric measurements, blood pressure, medical history, medication use, urine dipstick and biochemical measurements form electronic patient files. In addition, we performed a systematic literature review on kidney disease in PWS.RESULTS: We included 162 adults with genetically confirmed PWS (56% male, median age 28 years), of whom 44 (27%) had DM2. None had known CVD. All subjects had normal estimated glomerular filtration rate (eGFR) according to non-PWS reference intervals. Elevated urinary albumin or (micro)albuminuria was present in 28 (18%); 19 out of 75 (25%) had an increased urinary albumin-to-creatinine ratio (UACR) and 10 out of 57 (18%) had an increased urinary protein-to-creatinine ratio. Elevated urinary albumin was present at a young age (median age 26 (IQR 24-32) years) and was associated with an significantly higher BMI and LDL-cholesterol levels and higher prevalence of DM2, hypertension and dyslipidemia than those with normal UACR (p=0.027, p=0.019, p&lt;0.001, p&lt;0.001, p=0.011 and respectively).CONCLUSION: Upon screening, one in every five adults with PWS had increased urinary albumin or (micro)albuminuria, early signs of microvascular disease. All had normal eGFR, according to non-PWS reference intervals, and none had a formal diagnosis of CVD. As muscle mass is low in PWS, creatinine levels and eGFR may be spuriously normal. Urinalysis in this patient group can be used as a screening tool for microvascular (kidney) disease. We propose an algorithm for the detection and management of microvascular disease in adults with PWS.</p

Implementation fidelity trajectories of a health promotion program in multidisciplinary settings: managing tensions in rehabilitation care.

Although the importance of evaluating implementation fidelity is acknowledged, little is known about heterogeneity in fidelity over time. This study aims to generate insight into the heterogeneity in implementation fidelity trajectories of a health promotion program in multidisciplinary settings and the relationship with changes in patients' health behavior.This study used longitudinal data from the nationwide implementation of an evidence-informed physical activity promotion program in Dutch rehabilitation care. Fidelity scores were calculated based on annual surveys filled in by involved professionals (n = ± 70). Higher fidelity scores indicate a more complete implementation of the program's core components. A hierarchical cluster analysis was conducted on the implementation fidelity scores of 17 organizations at three different time points. Quantitative and qualitative data were used to explore organizational and professional differences between identified trajectories. Regression analyses were conducted to determine differences in patient outcomes.Three trajectories were identified as the following: 'stable high fidelity' (n = 9), 'moderate and improving fidelity' (n = 6), and 'unstable fidelity' (n = 2). The stable high fidelity organizations were generally smaller, started earlier, and implemented the program in a more structured way compared to moderate and improving fidelity organizations. At the implementation period's start and end, support from physicians and physiotherapists, professionals' appreciation, and program compatibility were rated more positively by professionals working in stable high fidelity organizations as compared to the moderate and improving fidelity organizations (p < .05). Qualitative data showed that the stable high fidelity organizations had often an explicit vision and strategy about the implementation of the program. Intriguingly, the trajectories were not associated with patients' self-reported physical activity outcomes (adjusted model β = - 651.6, t(613) = - 1032, p = .303).Differences in organizational-level implementation fidelity trajectories did not result in outcome differences at patient-level. This suggests that an effective implementation fidelity trajectory is contingent on the local organization's conditions. More specifically, achieving stable high implementation fidelity required the management of tensions: realizing a localized change vision, while safeguarding the program's standardized core components and engaging the scarce physicians throughout the process. When scaling up evidence-informed health promotion programs, we propose to tailor the management of implementation tensions to local organizations' starting position, size, and circumstances.The Netherlands National Trial Register NTR3961 . Registered 18 April 2013