Artifacts due to localized susceptibility effects, variations in the spin-lattice relaxation time constants of signals and a mixing of signals arising from tissue motions can contaminate otherwise credible results. The sources and magnitude of some of these are discussed and their likely impact assessed, so that the necessity of incorporating additional measurements in an individual study can be demonstrated.
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http://dx.doi.org/10.1002/nbm.1940020524 | DOI Listing |
Am J Physiol Heart Circ Physiol
January 2025
Sport Medicine Unit, Careggi University Hospital, Via delle Oblate 4, 50134 Florence, Italy.
The study was designed to investigate the pattern of intraventricular Hemo-Dynamic Forces (HDF) and myocardial performance during exercise in Elite Cyclists (EC). Transthoracic stress echocardiography was performed on nineteen EC and thirteen age-matched sedentary controls (SC) at three incremental exercise intensities based on Heart Rate Reserve (HRR). Left Ventricular (LV) HDF were computed from echocardiography long-axis data sets using a novel technique based on endocardial boundary tracking, both in apex-base and latero-septal directions.
View Article and Find Full Text PDFBiomed Phys Eng Express
January 2025
Dept. Mechanical Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, Chiba, 263-8522, JAPAN.
Albumin and γ-globulin concentrations in subcutaneous adipose tissues (SAT) have been quantified by multivariate regression based on admittance relaxation time distribution (mraRTD) under the fluctuated background of sodium electrolyte concentration. The mraRTD formulates P = Ac + Ξ (P: peak matrix of distribution function magnitude ɣP and frequency τP, c: concentration matrix of albumin cAlb, γ-globulin Gloc, and sodium electrolyte Nac, A: coefficient matrix of a multivariate regression model, and Ξ: error matrix). The mraRTD is implemented by two processes which are: 1) the training process of A through the maximum likelihood estimation of P and 2) the quantification process of cAlb, Gloc, and Nac through the model prediction.
View Article and Find Full Text PDFJ Mol Evol
January 2025
University of Engineering and Technology, Vietnam National University, 144 Xuan Thuy, Cau Giay, 10000, Hanoi, Vietnam.
One of the most important and difficult challenges in the research of molecular evolution is modeling the process of amino acid substitutions. Although single-matrix models, such as the LG model, are popular, their capability to properly capture the heterogeneity of the substitution process across sites is still questioned. Several mixture models with multiple matrices have been introduced and shown to offer advantages over single-matrix models.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata-700106, India.
Herein, we investigated the carrier-phonon relaxation process in a two-dimensional (2D) BAPbBr perovskite and its heterostructure with MoS. Energy transfer was observed in the van der Waals heterostructure of 2D perovskite and monolayer MoS, leading to enhancement in the photoluminescence intensity of MoS. Femtosecond pump-probe spectroscopy was used to study the carrier and lattice dynamics of pristine 2D materials and their heterostructure.
View Article and Find Full Text PDFMacromolecules
January 2025
Department of Materials Science & Engineering, Texas A&M University, College Station, Texas 77840, United States.
This work explored solution properties of linear and star poly(methacrylic acids) with four, six, and eight arms (PMAA, 4PMAA, PMAA, and 8PMAA, respectively) of matched molecular weights in a wide range of pH, salt, and polymer concentrations. Experimental measurements of self-diffusion were performed by fluorescence correlation spectroscopy (FCS), and the results were interpreted using the scaling theory of polyelectrolyte solutions. While all PMAAs were pH sensitive and showed an increase in hydrodynamic radius ( ) with pH in the dilute regime, the of star polymers (measured at basic pH values) was significantly smaller for the star polyacids due to their more compact structure.
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