Wide-gap CdTe strip detectors for high-resolution imaging in hard X-rays Nagasawa, Shunsaku; Minami, Takahiro; Watanabe, Shin ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2023, Volume:
1050
Journal Article
Peer reviewed
Open access
We propose a new strip configuration for CdTe X-ray detectors, named “Wide-gap CdTe strip detector”, in which the gap between adjacent strips is much wider than the width of each strip. It has been ...known that the observed energies of an incoming photon in adjacent strips can be utilized to achieve a position resolution finer than the strip pitch, if and only if the charge cloud induced by an incoming X-ray photon is split into multiple strips and their energies are accurately measured. However, with existing CdTe strip detectors, the ratio of such charge-sharing events is limited. An idea for a potential breakthrough to greatly enhance the ratio of charge-sharing events is to widen the gaps between strips on the detector. To test the concept, we developed a wide-gap CdTe strip detector, which has 64 platinum strip electrodes on the cathode side with some variations in strip pitches from 60 μm (30 μm strip and 30 μm gap width) to 80 μm (30 μm strip and 50 μm gap width). We evaluated the performance depending on the strip pitches by irradiating X-rays from 241Am on the detector. The charge loss due to the wider gaps on the detector was found to be significant to the extent that the assumption that the energy of an incoming photon for a charge-sharing event was the simple sum of the energies detected in adjacent strips lead to a significant degradation in the energy resolution in the accumulated spectrum, compared with those obtained with its predecessor having standard gap-widths. We then developed a new energy-reconstruction method to compensate for the charge loss. Application of the method to the data yielded a spectrum with a comparable spectral resolution with that of the predecessor. The ratio of the charge-sharing events for 17.8 keV events was doubled from that of the predecessor, from 24.3 to 49.9 percent. We assessed the results with a theoretical simulation based on the Shockley–Ramo theorem and found that they were in agreement.
Aims/Introduction
To prevent diabetic complications, strict glucose control and frequent monitoring of blood glucose levels with invasive methods are necessary. We considered the monitoring of tear ...glucose levels might be a possible method for non‐invasive glucose monitoring. To develop tear glucose monitoring for clinical application, we investigated the precise correlation between the blood and tear glucose concentrations.
Materials and Methods
A total of 10 participants and 20 participants with diabetes were admitted, and blood and tear samples were collected. Before statistical analysis, we eliminated tear samples contaminated with blood. We observed the daily blood and tear glucose dynamics, and carried out a random intercept model analysis to examine the association between the blood and tear glucose concentrations.
Results
Tear occult blood tests showed that the tear glucose concentrations and their variation increased in both participants with and without diabetes as contamination of blood increased. In both participants with and without diabetes, fluctuations of the plasma glucose concentrations were observed depending on the timing of collection of the samples, and the dynamics of the tear glucose concentrations paralleled those of the plasma glucose concentrations. The random intercept model analysis showed a significant association between the plasma and tear glucose concentrations in participants with diabetes (P < 0.001). This association still existed even after adjusting for the glycated hemoglobin levels and the prandial state (P < 0.001).
Conclusions
It is important to eliminate the tear samples contaminated with blood. Tear glucose monitoring might be a reliable and non‐invasive substitute method for monitoring the blood glucose concentrations for diabetes patients, irrespective of glycated hemoglobin levels and timing of sample collection.
It is important to eliminate the tear samples contaminated with blood. Tear glucose monitoring might be a reliable and non‐invasive substitute method for monitoring the blood glucose concentrations for diabetes patients, irrespective of glycated hemoglobin levels and the timing of sample collection.
In Japan, bridges are inspected via close visual examinations every five years. However, these inspections are labor intensive, and a shortage of engineers and budget constraints will restrict such ...inspections in the future. In recent years, efforts have been made to reduce the labor required for inspections by automating various aspects of the inspection process. In this study, we proposed and evaluated a method of applying super-resolution technology to obtain precise point cloud information to create distance information images to enable the use of tactile information (e.g., human touch) on the surface to be inspected. We measured the distance to the specimen using LiDAR, generated distance information images, performed super-resolution on the pseudo-created low-resolution images, and evaluated them in comparison with the existing magnification method. The evaluation results suggest that the adaptation of the super-resolution technique is effective in increasing the resolution of the boundary of the distance change.
Purpose
To evaluate cases with a retinal pigment epithelium (RPE) aperture using polarization-sensitive optical coherence tomography (PS-OCT).
Study design
Retrospective consecutive case series.
...Methods
A retrospective study that included three eyes (three patients) with RPE aperture and age-related macular degeneration (AMD) evaluated at the Macular Clinic in Tokyo University Hospital. A three-dimensional dataset of depolarization information was obtained with a clinical prototype of PS-OCT.
Results
All patients were categorized as intermediate AMD. RPE apertures were identified with PS-OCT as discontinuities of depolarization in the RPE layer of the pigment epithelial detachment (PED). A nonuniform decrease of depolarization in the RPE layer was also observed around the aperture. Two findings were observed above the aperture, intraretinal focal areas with high reflectivity and increased depolarization and subretinal bands with moderate reflectivity and low depolarization. Retinal sensitivity according to fundus microperimetry measured at 25 points was significantly associated with the degree of depolarization at the corresponding area (r-square = 0.60, p = 0.0001).
Conclusion
The RPE aperture was characterized as a round discontinuity of depolarization. The findings with PS-OCT suggest atrophic changes in the overlying RPE of the PED. The degree of depolarization was associated with retinal sensitivity. The current results indicate that RPE apertures developed within the spectrum of atrophic AMD.
In Japan, the final tightening of bolts in the bolt-tightening operations is guaranteed to have been performed correctly by visually determining the change in markings during the temporary tightening ...operation performed by the technician. However, the engineer must confirm many bolts; further, the amount of time needed for the confirmation work and the inability to keep an objective record of the confirmation results present problems. To solve these problems, we developed a system for automating the final tightening of bolts using deep learning-based image-processing technology. The proposed system takes as input videos of bolt fastening points, extracts individual bolts, extracts markings on the extracted bolts, and makes fastening decisions based on the markings. In the judgment stage, the system processes information on each bolt where a marking is detected; thus, it is possible to leave this information as objective data. In this paper, we evaluated the accuracy of each automated step using an actual bridge video. We also compared the confirmation time with human confirmation. As a result of the confirmation, our proposed method reduces the confirmation time by about 33% in comparison to human confirmation.
A number of drug-releasing contact lenses are currently being studied to address issues inherent in eye drops as a drug delivery method. In this study, we developed epinastine hydrochloride-releasing ...daily soft contact lenses for treatment of allergic conjunctivitis and examined their in vitro and in vivo performance. Preformed soft contact lenses with/without ionic functional groups were soaked in a solution of epinastine hydrochloride in phosphate-buffered saline to prepare epinastine hydrochloride-releasing soft contact lenses. Among these contact lenses with different ionicities, anionic lenses demonstrated the maximum, relatively linear epinastine hydrochloride release, in vitro. The amount of epinastine hydrochloride release was directly proportional to the concentration of the epinastine hydrochloride solution used to prepare the contact lens. The epinastine hydrochloride-releasing anionic soft contact lens also demonstrated prolonged drug release and significantly greater efficacy compared with epinastine hydrochloride eye drops 12 h after treatment, in vivo. Further studies are required to determine the appropriate amount of epinastine hydrochloride to be contained in the anionic soft contact lenses.
The first protecting group-free synthesis of N-glycosyl carbamates has been developed through reaction of d-glucose with n-butyl carbamate in acidic aqueous media. The structures of the N-glucosyl ...carbamates were unambiguously determined by comparison with authentic samples, prepared using the isocyanide method. With this protective group-free method for synthesis of N-glycosyl carbamates in hand, an anomeric pair of N-xylopyranosyl carbamates were prepared and used to assess the anomeric effect of nitrogen in the carbamate group.
Display omitted
•The first protecting group-free synthesis of N-glycosyl carbamates has been developed.
In the United States, many people have suffered losses caused by the collapse of deteriorated road bridges and subsequent road closures, and in Japan, bridges built during rapid economic growth are ...now reaching the end of their planned service period. Under these circumstances, instead of corrective maintenance, regular visual inspections of the bridges are performed once every five years to implement preventative maintenance. In this study, to identify those bridges prone to rapid deterioration, deterioration rates were calculated based on data from two cycles of inspection results, and the environmental factors that impacted these rates were statistically analyzed based on Hayashi’s quantification theory type I. The results clearly show that the bridge deterioration rate is significantly impacted by its specifications (superstructure materials, bridge length, year of construction), but that environmental factors also exert an equivalent impact. Therefore, considering environmental factors that can influence deterioration is expected to aid the development of more efficient and effective bridge maintenance plans.
To investigate the dynamics of the healing process after therapeutic subthreshold micropulse laser (SMPL) for diabetic macular edema (DME) using polarization-sensitive optical coherence tomography ...(PS-OCT). A total of 11 eyes of 11 consecutive DME patients were enrolled. No visible signs of SMPL treatment were detected on PS-OCT images. The entropy value per unit area (pixel.sup.2) in the RPE tended to decrease at 3 and 6 months from baseline (35.8 ± 17.0 vs 26.1 ± 9.8, P = 0.14; vs 28.2 ± 18.3, P = 0.14). Based on the en face entropy mapping, the overall entropy value did not change in each layer in the whole ETDRS grid; however, decrease of entropy in the RPE was observed at 2, 3, and 6 months post-treatment within the SMPL-irradiated sectors (P < 0.01, each). There was a positive correlation between the change rate of retinal thickness and that of entropy in the RPE within the SMPL-irradiated sector at 6 months (r.sup.2 = 0.19, P = 0.039). Entropy measured using PS-OCT may be a new parameter that facilitates objective monitoring of SMPL-induced functional changes in the RPE that could not previously be assessed directly. This may contribute to a more promising therapeutic evaluation of DME.
Hydroelectric power generates electricity with the potential energy of water flow. A penstock diameter over a range of several centimeters to several meters, one of the length over a range of several ...meters to several kilometers. A regular maintenance method of penstock needs a worker to approach penstock and check its surface by their eye. Maintenance workers must walk the distance from one end to the other of penstock to check the whole. This method needs a lot of time and cost. We propose an automatic maintenance method using a drone and an image processing method. This method uses the penstock picture taken by a drone to check the surface of the penstock. This picture is used as an input of a deep learning-based image processing method to extract the damaged area on the penstock. In this paper, we explain the overview of the proposed method, evaluate the damage extract method, discuss the remaining problems to realize the proposed method.
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