Wide dynamic range charge sensor operation by high-speed feedback control of radio-frequency reflectometry

Semiconductor quantum dots are useful for controlling and observing quantum states and can also be used as sensors for reading out quantum bits and exploring local electronic states in nanostructures. However, challenges remain for the sensor applications, such as the trade-off between sensitivity and dynamic range and the issue of instability due to external disturbances. In this study, we demonstrate proportional-integral-differential feedback control of the radio-frequency reflectometry in GaN nanodevices using a field-programmable gate array. This technique can maintain the operating point of the charge sensor with high sensitivity. The system also realizes a wide dynamic range and high sensor sensitivity through the monitoring of the feedback signal. This method has potential applications in exploring dynamics and instability of electronic and quantum states in nanostructures.Comment: 13 pages, 5 figure

Acute effects of exercise intensity on butyrylcholinesterase and ghrelin in young men: A randomized controlled study

Background/objectives: Butyrylcholinesterase (BChE), a liver-derived enzyme that hydrolyzes acylated ghrelin to des-acylated ghrelin, may trigger a potential mechanism responsible for the acute exercise-induced suppression of acylated ghrelin. However, studies examining the effects of an acute bout of high-intensity exercise on BChE and acylated ghrelin have yielded inconsistent findings. This study aimed to examine the acute effects of exercise intensity on BChE, acylated ghrelin and des-acylated ghrelin concentrations in humans. Methods: Fifteen young men (aged 22.7 ± 1.8 years, mean ± standard deviation) completed three, half-day laboratory-based trials (i.e., high-intensity exercise, low-intensity exercise and control), in a random order. In the exercise trials, the participants ran for 60 min (from 09:30 to 10:30) at a speed eliciting 70 % (high-intensity) or 40 % (low-intensity) of their maximum oxygen uptake and then rested for 90 min. In the control trial, participants sat on a chair for the entire trial (from 09:30 to 12:00). Venous blood samples were collected at 09:30, 10:00, 10:30, 11:00, 11:30 and 12:00. Results: The BChE concentration was not altered over time among the three trials. Total acylated and des-acylated ghrelin area under the curve during the first 60 min (i.e., from 0 min to 60 min) of the main trial were lower in the high-intensity exercise trial than in the control (acylated ghrelin, mean difference: 62.6 pg/mL, p < 0.001; des-acylated ghrelin, mean difference: 31.4 pg/mL, p = 0.035) and the low-intensity exercise trial (acylated ghrelin, mean difference: 87.7 pg/mL, p < 0.001; des-acylated ghrelin, mean difference: 43.0 pg/mL, p = 0.042). Conclusion: The findings suggest that BChE may not be involved in the modulation of ghrelin even though lowered acylated ghrelin concentration was observed after high-intensity exercise

Gum chewing while walking increases walking distance and energy expenditure: A randomized, single-blind, controlled, cross-over study

Background/objective: Gum chewing while walking increases walking distance and energy expenditure in middle-aged male and female individuals. This study aimed to examine the effects of gum chewing while walking on walking distance and energy metabolism in male and female individuals of various age groups. Methods: Fifty participants (25 male and 25 female individuals) aged 22–69 years completed two trials in a random order. In the gum trial, participants walked at a natural pace for 15 min while chewing two gum pellets (1.5 g, 3 kcal per pellet) following a 50-min rest period. In the tablet trial, participants rested for 50 min before walking, and the participants then walked at a natural pace for 15 min after ingesting two pellets of tablet containing the same ingredients with the exception of the gum base. The walking distance, step count, walking speed, stride, heart rate, energy expenditure, and respiratory exchange ratio were measured. Results: Walking distance, step count, walking speed, heart rate, and energy expenditure during walking were significantly higher in the gum trial than in the tablet trial. In participants aged ≥40 years, walking distance, walking speed, stride, heart rate, and energy expenditure during walking were significantly increased during the gum trial compared with those during the tablet trial. Conclusion: The study findings demonstrated that gum chewing while walking increased walking distance and energy expenditure in both male and female individuals

Development of the Leeds Food Preference Questionnaire in Japanese: Sensitivity and reproducibility of liking and wanting for food in fasted and fed states

The Leeds Food Preference Questionnaire (LFPQ), a computer-based task for measuring reward responses (liking/wanting) and preferences for images of food, is a widely used tool. However, no cultural adaptation studies to date have addressed its validity and repeatability in a test–retest design. The present study aimed to develop a Japanese version of the LFPQ (LFPQ-J); examine its outcomes under fasted and fed states; and test its reproducability after one week. An online survey containing foods that were either low-fat sweet, high-fat sweet, low-fat savoury or high-fat savoury was first conducted among a sample of 200 Japanese adults (100 men and 100 women) to develop and validate a culturally appropriate food image database. Sixty participants (30 men and 30 women) then participated in two identical trials where they completed the LFPQ-J under fasted and fed states (immediately after a standardised meal), at least one week apart. The absolute difference within the participants in scores for explicit liking, explicit wanting, implicit wanting and relative preference between the trials was analysed using Bland-Altman plots and Pearson’s or Spearman’s correlation coefficients. In the fasted state for each food category, 91.1 to 96.4 % of the data were plotted within the 95% limits of agreement and intra-personal correlation were 0.58–0.81. In the fed state for each food category, 91.1 to 98.2 % of the data were plotted within the 95% limits of agreement and intra-personal correlation were 0.40–0.83. The present study demonstrates that the LFPQ-J is a sensitive and reproducible instrument for the evaluation of liking and wanting for food varying in fat content and sweet taste in Japanese adults