159 research outputs found

    Influence of wall thickness and diameter on arterial shear wave elastography: a phantom and finite element study

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    Quantitative, non-invasive and local measurements of arterial mechanical properties could be highly beneficial for early diagnosis of cardiovascular disease and follow up of treatment. Arterial shear wave elastography (SWE) and wave velocity dispersion analysis have previously been applied to measure arterial stiffness. Arterial wall thickness (h) and inner diameter (D) vary with age and pathology and may influence the shear wave propagation. Nevertheless, the effect of arterial geometry in SWE has not yet been systematically investigated. In this study the influence of geometry on the estimated mechanical properties of plates (h = 0.5–3 mm) and hollow cylinders (h = 1, 2 and 3 mm, D = 6 mm) was assessed by experiments in phantoms and by finite element method simulations. In addition, simulations in hollow cylinders with wall thickness difficult to achieve in phantoms were performed (h = 0.5–1.3 mm, D = 5–8 mm). The phase velocity curves obtained from experiments and simulations were compared in the frequency range 200–1000 Hz and showed good agreement (R2 = 0.80 ± 0.07 for plates and R2 = 0.82 ± 0.04 for hollow cylinders). Wall thickness had a larger effect than diameter on the dispersion curves, which did not have major effects above 400 Hz. An underestimation of 0.1–0.2 mm in wall thickness introduces an error 4–9 kPa in hollow cylinders with shear modulus of 21–26 kPa. Therefore, wall thickness should correctly be measured in arterial SWE applications for accurate mechanical properties estimation

    A new neurocognitive interpretation of shoulder position sense during reaching: unexpected competence in the measurement of extracorporeal space

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    Background.The position sense of the shoulder joint is important during reaching. Objective. To examine the existence of additional competence of the shoulder with regard to the ability to measure extracorporeal space, through a novel approach, using the shoulder proprioceptive rehabilitation tool (SPRT), during reaching. Design. Observational case-control study. Methods. We examined 50 subjects: 25 healthy and 25 with impingement syndrome with a mean age [years] of 64.52 +/− 6.98 and 68.36 +/− 6.54, respectively. Two parameters were evaluated using the SPRT: the integration of visual information and the proprioceptive afferents of the shoulder (Test 1) and the discriminative proprioceptive capacity of the shoulder, with the subject blindfolded (Test 2). These tasks assessed the spatial error (in centimeters) by the shoulder joint in reaching movements on the sagittal plane. Results. The shoulder had proprioceptive features that allowed it to memorize a reaching position and reproduce it (error of 1.22 cm to 1.55 cm in healthy subjects). This ability was lower in the impingement group, with a statistically significant difference compared to the healthy group ( < 0.05 by Mann–Whitney test). Conclusions. The shoulder has specific expertise in the measurement of the extracorporeal space during reaching movements that gradually decreases in impingement syndrome

    Proteomics coupled with AhR-reporter gene bioassay for human and environmental safety assessment of sewage sludge and hydrochar

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    Today application of sewage sludge (SL) and hydrochar (HC) in agriculture is a common practice for soil conditioning and crop fertilization, however safety concerns for human and environmental health due to the presence of toxic compounds have recently been expressed. Our aim was to test the suitability of proteomics coupled with bioanalytical tools for unravelling mixture effects of these applications in human and environmental safety assessment. We conducted proteomic and bioinformatic analysis of cell cultures used in the DR-CALUXÂź bioassay to identify proteins differentially abundant after exposure to SL and the corresponding HC, rather than only using the Bioanalytical Toxicity Equivalents (BEQs) obtained by DR-CALUXÂź. DR-CALUXÂź cells exposed to SL or HC showed a differential pattern of protein abundance depending on the type of SL and HC extract. The modified proteins are involved in antioxidant pathways, unfolded protein response and DNA damage that have close correlations with the effects of dioxin on biological systems and with onset of cancer and neurological disorders. Other cell response evidence suggested enrichment of heavy metals in the extracts. The present combined approach represents an advance in the application of bioanalytical tools for safety assessment of complex mixtures such as SL and HC. It proved successful in screening proteins, the abundance of which is determined by SL and HC and by the biological activity of legacy toxic compounds, including organohalogens

    Inside the Michelangelo effect: The role of art and aesthetic attractiveness on perceived fatigue and hand kinematics in virtual painting

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    It has recently been discovered that during a virtual reality task of painting, if the subjects have the illusion of recreating an artistic masterpiece, they improve their performances and perceive less fatigue compared to simply coloring a virtual canvas. This phenomenon has been called the Michelangelo effect. However, it was unclear if this effect was related to the aesthetic experience of beauty or if it was specific to artistic stimuli. To clarify this point, 26 healthy subjects performed the virtual task of erasing a blank sheet on the canvas, revealing an image that could be a painting or a photo, classified as beautiful or not. Beautiful paintings were famous artistic portraits, non-beautiful paintings were rough reproductions of them. Photos of popular people were matched with paintings according to their similarity for somatic traits, posture, and clothes. Beautiful and non-beautiful photos were classified according to whether the pictured person was famous or not for their beauty. For each stimulus the objective beauty, subjective beauty, and effort to complete the task perceived by the subject were self-assessed on a numerical rating scale, recorded and analyzed. Furthermore, the hand kinematic trajectory was instrumentally recorded and its spatiotemporal parameters were computed. Less fatigue was perceived for the paintings than for the photos (p =&nbsp;.020), but not for beautiful versus non-beautiful stimuli (p =&nbsp;.325). Only in the artistic stimuli, subjective beauty was found to be negatively correlated with perceived fatigue (p =&nbsp;.030) and performed errors (p =&nbsp;.005). The kinematic parameters were found to be affected by the interactions between the gender of the participant and that of the person in the photo. These results supported the idea that the Michelangelo effect was stronger when subjects interacted with artefacts, modulated by the perceived beauty of the artistic stimulus
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