Study Design: Human and bovine cadaver study in which biochemical measurements and magnetic resonance (MR) imaging of intervertebral discs were correlated.
Objective: To measure the correlations between T2 relaxation time with water and proteoglycan (PG) content of intervertebral discs.
Summary Of Background Data: Measuring T2 relaxation times may provide an accurate noninvasive method of detecting changes in disc water content and biochemistry due to aging or degeneration. Previous studies to validate the use of T1 or T2 relaxation times of intervertebral disc tissue have used MR relaxometers, lower field strength imagers, and in 1 case a 1.5-T imager. The dependence of T2 relaxation times on water and PG content needs further validation in high field clinical MR imagers.
Methods: Multiecho MR images were obtained in 14 calf and 5 human cadaver discs. T2 relaxation times were calculated voxel by voxel for nucleus and anulus regions by fitting the decay of the signal intensity to an exponential model. Water and PG content were measured in samples of nucleus and anulus corresponding to the location of the T2 measurements. T2 relaxation times for calf and human specimens were correlated with water or PG content by regression analysis.
Results: T2 relaxation times correlated significantly with water content in human nucleus pulposus, human anulus fibrosus, and calf anulus. T2 relaxation time correlated significantly with PG content only in the calf anulus. When the human and calf nucleus and anulus specimens were combined, T2 relaxation times correlated strongly with water (R = 0.81, P < 0.001) and less strongly with PG (R = 0.57, P < 0.001) content.
Conclusion: T2 relaxation times of intervertebral disc anulus fibrosus and nucleus pulposus correlate strongly with water content and weakly with PG content.
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http://dx.doi.org/10.1097/BRS.0b013e318195dd44 | DOI Listing |
Chaos
January 2025
Classe di Scienze, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy.
Modeling how a shock propagates in a temporal network and how the system relaxes back to equilibrium is challenging but important in many applications, such as financial systemic risk. Most studies, so far, have focused on shocks hitting a link of the network, while often it is the node and its propensity to be connected that are affected by a shock. Using the configuration model-a specific exponential random graph model-as a starting point, we propose a vector autoregressive (VAR) framework to analytically compute the Impulse Response Function (IRF) of a network metric conditional to a shock on a node.
View Article and Find Full Text PDFMater Horiz
January 2025
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Circularly polarized luminescence (CPL) materials have developed rapidly in recent years due to their wide application prospects in fields like 3D displays and anti-counterfeiting. Utilizing energy transfer processes to transfer chirality has been proven as an efficient way to obtain CPL materials. However, the physics behind energy-transfer induced CPL is still not clear.
View Article and Find Full Text PDFSurg Laparosc Endosc Percutan Tech
January 2025
Department of Surgery, Division of Gastrointestinal Surgery, University of South Florida, Morsani College of Medicine, Tampa, FL.
Background And Aims: Several studies have hypothesized that sparing the oblique/sling fibers during posterior peroral endoscopic myotomy (POEM) may reduce the incidence of gastroesophageal reflux disease (GERD) and reflux esophagitis without compromising the established safety and efficacy of the procedure. This study compares perioperative, postoperative motility-related, and postoperative GERD-related outcomes between posterior oblique/sling fibers-sparing POEM (OFS-POEM) and conventional posterior POEM through a pairwise meta-analysis of comparative studies.
Methods: We conducted a systematic literature review following PRISMA guidelines to identify articles directly comparing posterior OFS-POEM with conventional posterior POEM.
Mater Today Bio
February 2025
Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary.
Mucosal membranes with strong variability in their viscoelastic properties line numerous organs and are often targeted by mucoadhesive formulations, e.g., highly swellable hydroxypropylmethylcellulose (HPMC) and slightly cross-linked poly(acrylic acid) (PAA) tablets.
View Article and Find Full Text PDFJPRAS Open
March 2025
Department of Plastic and Craniofacial Surgery, MITERA Hospital, Hellenic Healthcare Group (HHG), 6 Erithrou Stavrou str., 151 23 Maroussi, Attica, Greece.
Background: Despite a variety of principles proposed for drawing trilobed and quadrilobed flaps for the reconstruction of nasal skin defects, the application of these principles in a detailed and reliable way remains questionable.
Methods: We present a novel method for drawing trilobed and quadrilobed flaps to cover nasal tip skin defects. The method is based on the use of templates corresponding to four trilobed flaps with overall angles of 60°, 70°, 80°, and 90°, and two quadrilobed flaps with angles of 90° and 105°.
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