Abstract Rationale: Peutz-Jeghers syndrome (PJS), a rare autosomal dominant disorder, is characterized by mucocutaneous pigmentations, hamartomatous polyps in the gastrointestinal tract, and a high risk of developing various malignancies. To the best of our knowledge, only 1 case of appendiceal carcinoid associated with PJS has been previously reported in the pediatric population. Patient concerns: We report a 7-year-old girl who was admitted for severe, intermittent abdominal pain and cramps, nausea, and vomiting. Multiple brown melanotic macules on the lips, buccal mucosa, and the tongue were noted. Diagnosis: A plain abdominal X-ray in a standing position revealed dilated intestinal loops with multiple air-fluid levels. A computed tomography scan of the abdomen showing a “coffee bean” appearance of the jejunal loop with a transition point to the duodenal loop. Axial-contrast-enhanced computed tomography scan of the abdomen showing dilated jejunum loops, filled with fluid with the swirled appearance of mesentery typical for volvulus. The diagnosis of PJS was based on clinical findings along with the histopathologic confirmation of the hamartomatous polyps. Interventions: An emergency laparotomy was performed, revealing a jejunojejunal intussusception starting 40 cm from the duodenojejunal flexure. Jejunotomy revealed that a lead-point intussusception was a necrotic hamartomatous polyp. After resecting the involved jejunal necrotic segment, including the polyp, end-to-end jejuno-jejunal anastomosis was performed. Further exploration revealed the presence of a jejunal mass 80 cm from the duodenojejunal flexure identified as another hamartomatous pedunculated polyp. The polyp was resected, and the enterotomy was then closed transversely. The grossly normal appendix was also removed. Outcomes: Clinical findings along with the histopathologically confirmed hamartomatous polyps were consistent with PJS. An appendiceal carcinoid (well-differentiated neuroendocrine tumor, European Neuroendocrine Tumor Society stage pT2) was incidentally detected during histological examination of the appendix. The patient and parents were counseled accordingly, focusing on active surveillance and control of symptoms. Two additional hamartomatous polyps (gastric and jejunal) were detected endoscopically and resected in the fourth postoperative week. A regular, 1-year follow-up and surveillance revealed no complications or recurrences. Lessons: Unusual neoplasms can occasionally be encountered in well-defined syndromes such as PJS. Therefore, active follow-up and surveillance are mandatory for all patients with PJS.

Abstract This paper presents the study of deformations and Von-Misses stresses of the main shaft system during opening and closing operations of a rotary SF6 load break switch (LBS). The shaft consists of three axially connected parts made of steel where components are on ground potential and of plastic material, which is on high potential. The insulating shaft carries three rotating knife-blade contacts for the three phases. Static deformation of the insulating shaft is calculated by applying a defined torque between the two ends of the shaft. The results allow deducing the dynamic deformation. Maximum values of Von-Misses stresses are located at the geared connection between the plastic and the steel shaft. The rotation of the shaft system is measured synchronously by two optical rotary encoders in the front and rear sides of the LBS. The results confirm the twisting of the shaft system and provide its elastic deformation values. Travel curves obtained on both side of the LBS show different courses with respect to overtravel and rebound. Discrepancies can be explained by the deformation of the main shaft due to the acting forces, whereas manufacturing tolerances resulting in loose have a certain contribution.

Abstract The breaking capacity of a medium voltage (MV) rotary SF6 load break switch (LBS) can be improved by incorporating permanent magnets into the stationary contacts. The magnetic field is intended to blow the switching arc root towards a recessed space at the stationary contacts thereby preventing reignition of the arc after current zero. Making and breaking tests of load current 630 A were performed comparing the switching performance of load break switches equipped without a permanent magnet, with a ferrite and with a neodymium magnet. The impact of different polarity arrangements of the magnets in the three phases is also considered and analysed. In order to understand the arc behaviour caused by the effect of permanent magnet, arcing times and arc voltage were measured and evaluated. The results show that the arc voltage depends on the direction of the electromagnetic force, which is determined by the phase current direction but also by the polarity of the magnets. When the force is directed towards the recessed space at the stationary contacts, the arc voltage is notably higher than in the case where the arc is blown in the opposite direction. The higher arc voltage is a reliable indication that the length of the arc is increased, which significantly reduces the risk of both thermal and dielectric breakdowns after the first current zero. The consequences are noticed first in the reduction of the number of missed current zeroes and second in shorter minimum arcing times. An adverse arrangement of the magnet polarity in the three phases increases the number of missed current zeroes.

ntroduction: Sleep is one of the most important components of overall health. Children with developmental disabilities are at a higher risk of having sleep problems. Purpose: The goal of the present study is to compare sleep patterns of children with developmental disabilities with those of typically developing children. In particular, we examined whether children with an intellectual disability (ID), children with an autism spectrum disorder (ASD) and typically developing children differ in sleep duration, number of night’s waking, screen time (time spent on smartphones, tablets, TV), and outdoor activities. Methods: The sample for this study consisted of 114 children (34 children with ASD, 40 children with ID and 40 typically developing children) aged 2 to 14 years (mean age= 6.4 years, SD = 3.0). Information on children’s sleep patterns was obtained through an online survey completed by the parents of the children. We also collected information regarding the strategies parents use to settle their children for sleep, as well as information regarding screen time and outdoor activities. Results: The results of this study indicate that sleep duration was shortest for children with ID and longest for children without developmental disabilities. Another finding in this study is that screen time and not the outdoor activities was associated with sleep duration. Children with ASD were more likely to use melatonin to fall asleep, while the children with ID were more likely to use medications. Conclusion: Children with ID have shorter sleep duration than children with ASD and typically developing children. Parents have several cognitive and behavioural strategies at their disposal to improve their children’s sleep.

Abstract This paper describes the advantages of using data acquisition systems and software modelling tools to support the assessment and therefore redesign of the existing medium voltage switchgear. A 38kV/630A load break linear puffer (LP) will be used as an example for this study. In house testing was conducted to capture important design parameters of the switch such as displacement, velocity of mechanical parts and gas pressure using various sensors and three different measurement setups. The first setup, which is primarily intended for no-load measurements, consists of a DAQ system equipped with different types of sensors - two rotational encoders, three laser-based distance sensors, six pressure sensors, contact separation measurement, and a high-speed camera integrated and synchronized with the measurement system. The second and third setups, which are suitable both for no-load and on-load measurements, are based on state-of-the-art DAQ systems, which use three piezo-electric based pressure sensors, two fibre-optic based pressure sensors, three laser-based distance sensors and a high speed camera synchronized with the measurement system. The data acquired by the measurement systems is used in combination with an in-house developed simulation software HV CB Simulation, which enables simulating and predicting various variables of switching devices. Moreover, high speed camera videos analysed with both commercial and in-house developed image processing software, visualize and reveal many otherwise inaccessible occurrences. In addition to a comprehensive analysis of the proposed data acquisition and simulation setups, three design improvements in the linear puffer design - increase of the opening speed, removal of the flexible conductors and the length increase of the puffer cylinder - are presented and discussed in this paper.

Abstract In recent years, significant achievements have been made with respect to the development of SF6-free gas insulated substations (GIS). In parallel, the interest in installing SF6-free GIS by utilities increased steadily and tenders for new substations or upgrades, which regularly also include alternative technologies. The excellent performance of SF6 was unequivocally accepted by all vendors and users so that the community became used to single technology solutions. This is no longer the case with alternative gas mixtures, and multiple technological solutions are available. However, from the present body of literature it is not possible to make a full and comparative evaluation of different alternative gas switchgear, i.e. circuit-breakers and disconnectors. Thus, the High-Voltage Laboratory of ETH Zürich started investigations and measurements of basic experiments that allow an unbiased comparison of properties of alternative gas mixtures relevant for switching. The two main purposes of these investigations are to define a set of measurements that allow an estimation and comparison of switching performance with different gas mixtures, independent of a specific interruption nozzle geometry, drive system, electrostatic design, and other design specific features, and to perform (some of) these measurements comparing pure SF6, with air, pure CO2, CO2/O2 mixture, and further specific gas mixtures that are currently proposed by manufacturers for SF6 replacement. The basic analysis behind the definition of measurements will be given in detail and the design principles of the chosen test devices and the derived test currents and diagnostics will be introduced. Test results themselves will not be given, rather they will be the subject of separate future publications.

Abstract The importance of the high voltage circuit breaker for the power system’s safe and reliable operation is paramount. This research aims to analyse and provide the most significant high voltage circuit breaker health state indices based on the non-invasive vibration fingerprint measurement method. Results obtained and presented in this paper are validated on the data set acquired from the vacuum circuit breaker.