Need for transverse strain data for fitting constitutive models of arterial tissue to uniaxial tests.

The study deals with the process of estimation of material parameters from uniaxial test data of arterial tissue and focuses on the role of transverse strains. Two fitting strategies are analyzed and their impact on the predictive and descriptive capabilities of the resulting model is evaluated. The standard fitting procedure (strategy A) based on longitudinal stress-strain curves is compared with the enhanced approach (strategy B) taking also the transverse strain test data into account.

Biaxial stretch can overcome discrepancy between global and local orientations of wavy collagen fibres.

Most frequently used structure-based constitutive models of arterial wall apply assumptions on two symmetric helical (and dispersed) fibre families which, however, are not well supported with histological findings where two collagen fibre families are seldom found. Moreover, bimodal distributions of fibre directions may originate also from their waviness combined with ignoring differences between local and global fibre orientations. In contrast, if the model parameters are identified without histological information on collagen fibre directions, the resulting mean angles of both fibre families are close to ±45°, which contradicts nearly all histologic findings.

Poisson's ratio and compressibility of arterial wall - Improved experimental data reject auxetic behaviour.

Poisson's ratio of fibrous soft tissue is analyzed in this paper on the basis of direct experimental measurements of porcine arterial wall layer under uniaxial tension and immersed in tempered saline bath. The current study follows the previously published testing methodology but with a new totally redesigned testing apparatus allowing more credible and precise evaluation of arterial wall behaviour. The new results confirm most of previous findings focused on positivity/negativity of Poisson's ratio playing a crucial role in (in)validation aspects of some constitutive models widely used in recent computational vascular mechanics.

The Staff Views About Assessing Voices Questionnaire: Piloting a Novel Socratic Method of Evaluating and Training Multidisciplinary Staff's Cognitive Assessment of Patients' Distressing Voices.

Cognitive features of auditory hallucinations (voices) have important clinical significance and their assessment is vital for cognitive behavior therapy to be more widely deployed by multidisciplinary staff. Using a new Socratic instrument-The Staff Views About Assessing Voices Questionnaire (SVAVQ)-we surveyed a community inpatient rehabilitation multidisciplinary workforce's ( = 50) assessment and attitude toward asking cognitive questions about patients' voices. We found that there were many clinically important gaps in what staff asked about in relation to cognitive features of voices.

Compressibility of arterial wall - Direct measurement and predictions of compressible constitutive models.

Volumetric compressibility and Poisson's ratios of fibrous soft tissues are analyzed in this paper on the basis of constitutive models and experimental data. The paper extends the previous work of Skacel and Bursa (J Mech Behav Biomed Mater, 54, pp. 316-327, 2016), dealing with incompressible behaviour of constitutive models, to the area of compressibility.