Fiber Bragg grating (FBG) based sensors have recently been introduced to the field of magnetic resonance imaging (MRI). Real-time MRI applications demand highly amplitude and phase sensitive MRI compatible sensors. Thus, a model and detailed analysis of FBG based ultrasound detection are required for designing better performing sensors. A hybrid FBG model incorporating numerical and FEA methods was developed and used for sensitivity and linearity analysis. The transfer matrix method was used for the modeling of optical modulation whereas FEA was used for pressure field calculations within the grating. The model was verified through reflection spectrum and acoustic pressure sensitivity testing of two -phase shifted FBGs in a side slope read-out configuration. The sensitivity curves with respect to the operation point on the side slope was characterized in terms of amplitude and phase, and nonlinearity of the phase response has been quantified. Lastly, the impact of phase linearity of the FBG based acousto-optic sensor was tested under MRI when the sensor was used as a position marker and an analog phase shifter based solution was demonstrated.
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http://dx.doi.org/10.1364/osac.385969 | DOI Listing |
BMC Public Health
December 2024
Medical College of Tibet University, No. 10 East Zangda Road,Chengguan District, Lhasa, 850000, China.
Background: The prevalence of hypertension among the Tibetan population in Tibet is higher than in other regions of China, and there is a lack of unified epidemiological surveys. This study aims to conduct a standardized epidemiological investigation to assess the current status of hypertension among the Tibetan population, as well as to explore the dose-response relationship between cholesterol (TC), triglyceride glucose index (TyG), triglyceride glucose-body mass index (TyG-BMI), and hypertension in this population.
Methods: From June 2020 to July 2023, a total of 5042 Tibetans aged 18 to 80 years from three cities and one region in Tibet were randomly sampled for the study.
AJNR Am J Neuroradiol
December 2024
From the Department of Radiology (H.N.M., F.B.G.), Bai Jerbai Wadia Hospital for Children, Mumbai, Maharashtra, India.
Background And Purpose: Congenital vertebral anomalies are commonly associated with underlying spinal cord anomaly which necessitates imaging both the spinal cord and the bony vertebral column to understand the extent of the deformity better. While MRI is the gold standard for spinal cord imaging, it does not provide CT-like bone details. Many MR bone imaging techniques have been tested in various adult spine conditions in the past decade but not much has been described on their reliability in pediatric spine.
View Article and Find Full Text PDFFront Nutr
December 2024
Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
Background: This systematic review and meta-analysis examine the effects of okra consumption on cardiometabolic risk factors in individuals with prediabetes and diabetes. Okra is a widely consumed vegetable with potential health benefits, and understanding its impact on metabolic parameters in these populations is important.
Methods: A comprehensive search of the literature was conducted up to May 2024 in PubMed/Medline, Scopus, and Web of Science to find relevant randomized clinical trials (RCTs) by using following keyword: ("okra" OR "okras" OR "") AND ("intervention" OR "controlled trial" OR "randomized" OR "randomized" OR "randomly" OR "clinical trial" OR "trial" OR "randomized controlled trial" OR "randomized clinical trial" OR "RCT" OR "blinded" OR "placebo" OR "Cross-Over" OR "parallel").
Nan Fang Yi Ke Da Xue Xue Bao
December 2024
Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China.
Objectives: To investigate the risk factors of recurrence of acute ischemic stroke (AIS) within 1 year and establish a nomogram model for predicting the recurrence risk.
Methods: This study was conducted in two cohorts of AIS patients (≤7 days) hospitalized in Dongzhimen Hospital (modeling set) and Fangshan Hospital (validation set) from March, 2021 to March, 2022. Lasso regression analysis was used to identify the important predictive factors for AIS recurrence within 1 year, and multivariate Logistic regression analysis was performed to analyze the independent factors affecting AIS recurrence.
A wavelength demodulation method for ultra-short fiber Bragg grating (US-FBG) sensors based on an arrayed waveguide grating (AWG) and a convex optimization algorithm is proposed and demonstrated. Instead of measuring the output power ratio of the two adjacent AWG channels as previously done, in this work the wavelength demodulation is realized by reconstructing the US-FBG spectrum. The principle of spectral reconstruction involves using an AWG to sample the spectral information of US-FBG and constructing underdetermined matrix equations with the obtained prior information on transmission responses and the detected output power from multiple AWG channels.
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