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The measurement speed is an important parameter of terahertz time-domain spectroscopy (THz-TDS) instruments. To improve the measurement speed of the spectrometer we need to increase the scanning speed of the delay line. In this paper, we study the influence of the scanning speed, the time constant of lock-in amplifier and the sampling rate on the signal quality. The results show that, when the time constant equal to 10 ms, increasing the scanning speed does not cause significant changes in the amplitude of the signal. But when the time constant equal to 30, 100 and 300 ms, with the increasing of the scanning speed the signal amplitude decreases rapidly. Therefore, the time constant should be set as small as possible to avoid deterioration of signal quality. On the other hand, higher the scanning speed is, fewer data points are collected with a same time-domain length. Therefore, when the scanning speed increase, not only the time constant should be reduced, but also the sampling rate should be increased to avoid the distortion of signal waveform caused by the number reduction of data points. The conclusions can provide a reference for improving the measurement speed of THz-TDS instrument.
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J Pediatr Urol
August 2025
Gaziantep University Medical Faculty, Department of Urology, Gaziantep, Turkey. Electronic address:
Objective: The most common chronic complication of vesicoureteral reflux (VUR) is the presence of renal scarring and dimercapto succinic acid (DMSA) renal scan is utilized for its detection. In this study, we have aimed to assess whether shear wave speed (SWS) differs between normal and refluxing kidneys.
Materials And Method: Fifty pediatric VUR patients and 21 healthy children with available DMSA obtained within the previous year were included in the study.
Perfluorinated and polyfluoroalkyl compounds (PFASs) represent a category of synthetic chemicals renowned for their environmental persistence. Owing to their hydrophobic, oleophobic, and high-temperature-resistant properties, PFASs are extensively utilized in industrial, agricultural, and civilian sectors, including applications in leather, textiles, flame-retardant materials, lubricants, and coatings, among others. PFASs can accumulate within the human body, exhibiting multi-organ toxicity.
View Article and Find Full Text PDFEye (Lond)
September 2025
NIHR Moorfields Clinical Research Facility, Moorfields Eye Hospital NHS Foundation Trust, London, UK.
Background/objectives: Hyporeflective clumps (HRC) are a common finding in adaptive optics ophthalmoscopy (AOO) of age-related macular degeneration (AMD). They appear on optical coherence tomography (OCT) as hyperreflective foci (HRF) or abutting the retinal pigment epithelium (RPE) layer as RPE thickening. The cellular origin of HRF is debated between migrated RPE cells and mononuclear phagocytes (MP).
View Article and Find Full Text PDFMed Phys
August 2025
The University of Texas MD Anderson Cancer Houston, Houston, Texas, USA.
Background: To guarantee high-quality patient scans, thorough quality assurance (QA) of SPECT or gamma cameras, including performance, review, and documentation, is essential.
Purpose: We developed a novel Nuclear Medicine Quality Assurance server (NMQA) with an AI deep learning (AIDL) optical character recognition (OCR) system to automate QA data retrieval and review from SPECT and gamma cameras. The system extracts and compares daily and weekly QA data against specifications.
Med Phys
August 2025
GE HealthCare MICT, Stockholm, Sweden.
Background: Photon-counting computed tomography (CT) bears promise to substantially improve spectral and spatial resolution. One reason for the relatively slow evolution of photon-counting detectors in CT-the technology has been used in nuclear medicine and planar radiology for decades-is pulse pileup, that is, the random staggering of pulses, resulting in count loss and spectral distortion, which in turn cause image bias and reduced contrast-to-noise ratio (CNR). The deterministic effects of pileup can be mitigated with a pileup-correction algorithm, but the loss of CNR cannot be recovered, and must be minimized by hardware design.
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