Development of a high-speed, phase-sensitive laser probe system for RF surface/bulk acoustic wave devices with an autofocus function for long time continuous operation

This paper describes the implementation of the autofocus function for the laser beam into the high-speed, phase-sensitive laser probe system for RF SAW/BAW devices. This implementation can compensate defocus caused during continuous measurements that take dozens of hours. After a brief explanation of the system used in this work, detailed discussion is given on an employed evaluation function indicating focus status, which is a key factor determining autofocus reliability. It is shown that the sum of energy of Laplacians is suitable as the evaluation function, which can be calculated by the image of the probing laser spot captured by a build-in CCD camera. Then, the implementation of the autofocus function into the current system is detailed. It is confirmed that this function can adjust the focus within almost ±20 μm defocus conditions. Finally, it is confirmed how the implemented autofocus function works effectively to keep just-in-focus under the disturbance.

Designing and Analyzing 3D-Printed Personal Steering Controller for Outdoor Electric-Powered Wheelchair Users: A Randomized Controlled Trial on Stroke Patients

While the physical conditions of stroke patients are diverse, the joystick-type steering controller of the electric-powered wheelchair (EPW) is almost the same, making the user uncomfortable and not fully utilizing the function of the wheelchair. The purpose of this study was to investigate the effects of the EPW steering controller, specifically the so-called joystick type (3DSC; 3D-printed steering controller, conventional steering controllers; CSC), on surface electromyography (sEMG), Wheelchair Skills Test 4.2 (WST), and QUEST 2.0. The participants were 23 hemiplegic stroke patients (14 males and 9 females) (range 40–65 years) recruited from multi-center process. The 3DSC manufacturing process used a scanner (Precision Laser Probe SLP-500) and a modelling program (SOLIDWORKS 2015). The CSC users’ muscle activities were generally higher than those of the 3DSC users in both males and females (p < 0.05). WST total performance score of CSC is statistically significantly lower than those of 3DSC for both males (3DSC = 49.28 ± 2.19; CSC = 42.85 ± 4.31) (z = −3.935; p < 0.05) and females (3DSC = 48.17 ± 0.44; CSC = 41.11 ± 0.78) (z = −1.910; p < 0.05). QUEST 2.0 scores in CSC (male = 2.40 ± 0.70; female = 2.11 ± 0.78) were significantly lower than those of 3DSC (male = 3.50 ± 0.85; female = 2.90 ± 0.51) in effectiveness categories (p < 0.05). We suggest that 3DSC contributes to reducing the user’s muscle activities and raising the scores of WST performance and QUEST.

Pilonidal Disease Treatment By Radial Laser Surgery (FilaC™): The First Finnish Experience

Background and Aims: Pilonidal disease is common, and it afflicts especially young adults, causing disability. Several types of treatment methods are applicable, but no consensus exists regarding the best method. The aim of our study was to assess the novel radial laser probe treatment in pilonidal disease and report the success rate and recurrence rate. Methods: We studied retrospectively 86 patients who, according to our hospital patient records, underwent radial laser probe surgery between January 2017 and September 2019. Results: In a mean follow-up time of 14 months, the success rate at 2 months was 86%. Most operations were done under local anesthesia on a day-surgery basis. The recovery time was rapid, and median sick leave was 12 days. Of those initially successfully treated, 3% developed a recurrence. Altogether 17% of the patients underwent a re-operation. Spillage of pus during surgery, however, reduced the success rate to 53%. Conclusion: Radial laser probe treatment is a quick, safe, and minimally invasive treatment choice for pilonidal disease, especially when no active infection is present.

A Review of In Situ Isotopic Studies of the Oklo and Bangombé Natural Fission Reactors Using Microbeam Analytical Techniques

Isotopic analyses of elements in the natural reactor materials have often been performed to understand the distribution behaviors of the fission products and to evaluate the function of nuclear reactions since the first discovery of a natural reactor in 1972. Several types of unique microminerals, including significant amounts of fission products, have been found in and around the Oklo and the Bangombé natural reactors. In the past two decades, microbeam techniques using ion and laser probe facilities have been effectively applied for the in situ isotopic analyses of individual microminerals to investigate the migration behaviors of fissiogenic radioisotopes produced in the reactors. This paper presents a review of interpretations of the isotopic results of microminerals found in and around the natural reactors.