In this paper a fluid‐structure interaction (FSI) experiment is presented. The aim of this experiment is to provide a challenging yet easy‐to‐setup FSI test case that addresses the need for rigorous testing of FSI algorithms and modeling frameworks. Steady‐state and periodic steady‐state test cases with constant and periodic inflow were established. Focus of the experiment is on biomedical engineering applications with flow being in the laminar regime with Reynolds numbers 1283 and 651. Flow and solid domains were defined using computer‐aided design (CAD) tools. The experimental design aimed at providing a straightforward boundary condition definition. Material parameters and mechanical response of a moderately viscous Newtonian fluid and a nonlinear incompressible solid were experimentally determined. A comprehensive data set was acquired by using magnetic resonance imaging to record the interaction between the fluid and the solid, quantifying flow and solid motion.

Characterisation of soft tissue mechanical properties is a topic of increasing interest in translational and clinical research. Magnetic resonance elastography (MRE) has been used in this context to assess the mechanical properties of tissues in vivo noninvasively. Typically, these analyses rely on linear viscoelastic wave equations to assess material properties from measured wave dynamics. However, deformations that occur in some tissues (e.g. liver during respiration, heart during the cardiac cycle, or external compression during a breast exam) can yield loading bias, complicating the interpretation of tissue stiffness from MRE measurements. In this paper, it is shown how combined knowledge of a material's rheology and loading state can be used to eliminate loading bias and enable interpretation of intrinsic (unloaded) stiffness properties. Equations are derived utilising perturbation theory and Cauchy's equations of motion to demonstrate the impact of loading state on periodic steady-state wave behaviour in nonlinear viscoelastic materials. These equations demonstrate how loading bias yields apparent material stiffening, softening and anisotropy. MRE sensitivity to deformation is demonstrated in an experimental phantom, showing a loading bias of up to twofold. From an unbiased stiffness of [Formula: see text] Pa in unloaded state, the biased stiffness increases to 9767.5 [Formula: see text]1949.9 Pa under a load of [Formula: see text] 34% uniaxial compression. Integrating knowledge of phantom loading and rheology into a novel MRE reconstruction, it is shown that it is possible to characterise intrinsic material characteristics, eliminating the loading bias from MRE data. The framework introduced and demonstrated in phantoms illustrates a pathway that can be translated and applied to MRE in complex deforming tissues. This would contribute to a better assessment of material properties in soft tissues employing elastography.

This review on magnetic resonance elastography (MRE) of the breast provides an overview of available literature and describes current developments in the field of breast MRE, including new transducer technology for data acquisition and multi-frequency-derived power-law behaviour of tissue. Moreover, we discuss the future potential of breast MRE, which goes beyond its original application as an additional tool in differentiating benign from malignant breast lesions. These areas of ongoing and future research include MRE for pre-operative tumour delineation, staging, monitoring and predicting response to treatment, as well as prediction of the metastatic potential of primary tumours.

Being able to predict the mechanical properties of vertebrae in patients with osteoporosis and other relevant pathologies is essential to prevent fractures and to develop the most favorable fracture treatments. Furthermore, a reliable prediction is important for developing more patient-and pathology-specific biomaterials. A plethora of studies correlating bone density to mechanical properties has been reported; however, the results are variable, due to a variety of factors, including anatomical site and methodological differences. The aim of this study was to provide a comprehensive literature review on density and mechanical properties of human vertebral trabecular bone as well as relationships found between these properties. A literature search was performed to include studies, which investigated mechanical properties and bone density of trabecular bone. Only studies on vertebral trabecular bone tissue, reporting bone density or mechanical properties, were kept.A large variation in reported vertebral trabecular bone densities, mechanical properties, and relationships between the two was found, as exemplified by values varying between 0.09 and 0.35 g/cm 3 for the wet apparent density and from 0.1 to 976 MPa for the elastic modulus. The differences were found to reflect variations in experimental and analytical processes that had been used, including testing protocol and specimen geometry. The variability in the data decreased in studies where bone tissue testing occurred in a standardized manner (eg, the reported differences in average elastic modulus decreased from 400% to 10%). It is important to take this variability into account when analyzing the predictions found in the literature, for example, to calculate fracture risk, and it is recommended to use the models suggested in the present review to reduce data variability.

Both techniques facilitated good clinical results in combination with absorbable cement augmentation. In particular, the VBS enabled us to benefit from the advantages of the resorbable isothermic CaP cement with an improved radiological outcome in the long term compared to BKP. However, there was a mentionable loss of reduction in the follow-up in both groups compared to previously published data with PMMA cement. These slides can be retrieved under Electronic Supplementary Material.

The high stiffness of bone cements used in vertebroplasty has been hypothesized to contribute to the propensity of adjacent vertebral fractures after treatment. Therefore, new lowmodulus cements have been developed; however, there are currently no studies assessing the biomechanical aspects of vertebroplasty with these cements in an ex vivo non-prophylactic model. In this study, we induced wedge fractures through eccentric uniaxial compression to single wholevertebrae, before and after augmentation with either standard or low-modulus cement. Compressive strength and stiffness of individual vertebrae were measured, on 19 samples from metastatic spines and 20 samples from elderly, osteopenic spines. While both cement types increased the strength of both the metastatic (+34% and +63% for standard and low-modulus cement, respectively) and the elderly vertebrae (+ 303% and +113%, respectively), none of them restored the initial stiffness of metastatic specimens (-51% and -46%, respectively). Furthermore, low-modulus cement gave a lower total stiffness (-13%) of elderly specimens whereas standard cement increased it above initial levels (+17%). Results show that vertebroplasty with low-modulus cement could provide restoration of the initial stiffness while increasing the strength of fractured elderly vertebrae and hence represent a treatment modality which is closer to pre-augmented behaviour. Also, this study indicates that stiffness-modified cement needs to be optimized for patient/pathology specific treatment. The high stiffness of bone cements used in vertebroplasty has been hypothesized to contribute to the propensity 2 of adjacent vertebral fractures after treatment. Therefore, new low-modulus cements have been developed; 3 however, there are currently no studies assessing the biomechanical aspects of vertebroplasty with these 4 cements in an ex vivo non-prophylactic model. In this study, we induced wedge fractures through eccentric 5 uniaxial compression to single whole-vertebrae, before and after augmentation with either standard or low-6 modulus cement. Compressive strength and stiffness of individual vertebrae were measured, on 19 samples 7 from metastatic spines and 20 samples from elderly, osteopenic spines. While both cement types increased the 8 strength of both the metastatic (+34% and +63% for standard and low-modulus cement, respectively) and the 9 elderly vertebrae (+ 303% and +113%, respectively), none of them restored the initial stiffness of metastatic 10 specimens (-51% and -46%, respectively). Furthermore, low-modulus cement gave a lower total stiffness (-11 13%) of elderly specimens whereas standard cement increased it above initial levels (+17%). Results show that 12 vertebroplasty with low-modulus cement could provide restoration of the initial stiffness while increasing the 13 strength of fractured elderly vertebrae and hence represent a treatment modality which is closer to pre-14 augmented behaviour. Also, this study indicates that stiffness-modified cement needs to be optimized ...

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На основі розгляду полівінілхлориду (ПВХ) як сукупності флуктуаційних структурних елементів зі скінченним часом життя досліджено специфіку поведінки композиту в температурному діапазоні 298 К ≤ Т ≤ ≤ (Т с + 10) К. Показано, що при вмісті нанодисперсної міді та ніхрому, отриманих фізико-хімічним методом та/або методом електричного вибуху провідника в кількості від 0 до 5,0% об., в ПВХ-системі відбуваються суттєві зміни густини (ρ) і питомого об'єму (V), які є важливими структурними й термодинамічними характеристиками матеріалу. Встановлено кількісний взаємозв'язок між ρ, V, Т, механічними (модуль пружності, коефіцієнт стисливості) та тепловими (ентропія, термодеструкція, теплоємність, фактор ангармонічності) властивостями композиту. З використанням рівняння стану ПВХ-системи, отриманого на основі потенціалів