A theoretical analysis of the correlation between radio-frequency (RF) echo signal data acquired from the same location but at different angles is presented. The accuracy of the theoretical results is verified with computer simulations. Refinements to previous analyses of the correlation of RF signals originating from the same spatial location at different angular positions are made. We extend the analysis to study correlation of RF signals coming from different spatial locations and eventually correlation of RF signal segments that intersect at the same spatial location. The theory predicts a faster decorrelation with a change in the insonification angle for longer RF echo signal segments. As the RF signal segment becomes shorter, the decorrelation rate with angle is slower and approaches the limit corresponding to the correlation of RF signals originating from the same spatial location. Theoretical results provide a clear understanding of angular compounding techniques used to improve the signal-to-noise ratio in ultrasonic parametric imaging and in elastography.
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http://dx.doi.org/10.1109/tuffc.2005.1504018 | DOI Listing |
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MOE/NHC/CAMS Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
The gut microbiota plays a pivotal role in anxiety regulation through pathways involving neurotransmitter production, immune signaling, and metabolic interactions. Among these, gut-derived serotonin (5-hydroxytryptamine, 5-HT), synthesized from tryptophan metabolism, has been identified as a key mediator. However, it remains unclear whether specific microbial factors regulate tryptophan metabolism to influence 5-HT production and anxiety regulation.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University of Kentucky College of Medicine, Sanders-Brown Center on Aging, Lexington, KY, USA.
Background: We currently lack in the dementia field accurate, noninvasive, quick, and affordable screening tools for brain dysfunctions associated with early subtle risk of mild cognitive impairment (MCI). Our Kentucky aging cohort demonstrates that asymptomatic older individuals with MCI-like frontal memory-related brainwave patterns convert to MCI within a short 5-year period, as opposed to individuals with NC-like patterns (1) that remain normal 10 years later (2). Astrocyte reactivity influences amyloid-ß effects on tau pathology in preclinical Alzheimer's disease (3).
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Newcastle University, Newcastle, Tyne and Wear, UK.
Background: Digital mobility outcomes (DMOs) can be captured using body-worn inertial measurement units (IMUs) in lab-based and real-world environments. DMOs may support differential diagnosis of dementia; for example, Alzheimer's disease (AD) and Lewy body disease (LBD) show unique signatures of gait impairment. Growing evidence suggests that turning impairments are related to cognitive decline.
View Article and Find Full Text PDFInt J Med Sci
January 2025
Department of Urology, Kidney and Urology Center, the Seventh Affiliated Hospital of Sun Yat-Sen University, Shenzhen, China.
Doublecortin-like kinase 1 (DCLK1) has been revealed to be involved in modulating cancer stemness and tumor progression, but its role in prostate cancer (PCa) remains obscure. Castration-resistant and metastatic PCa exhibit aggressive behaviors, and current therapeutic approaches have shown limited beneficial effects on the overall survival rate of patients with advanced PCa. This study aimed to investigate the biological role and potential molecular mechanism of DCLK1 in the progression of PCa.
View Article and Find Full Text PDFInt J Biol Sci
January 2025
Department of Urology, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China.
Clear cell renal cell carcinoma (ccRCC) is one of the most common and aggressive malignancies of the urinary system. Despite being the first-line treatment for advanced ccRCC, vascular endothelial growth factor receptor inhibitors (VEGFRis) face significant limitations due to both initial and acquired resistance, which impede complete tumor eradication. Using a CRISPR/Cas9 library screening approach, was identified as a resistance-associated gene for three prevalent VEGFRis (Sunitinib, Axitinib, and Sorafenib).
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