OBJECTIVE:To summarize the predictors and outcomes of empathy by health care personnel, methods used to study their empathy, and the effectiveness of interventions targeting their empathy, in order to advance understanding of the role of empathy in health care and facilitate additional research aimed at increasing positive patient care experiences and outcomes.DATA SOURCE:We searched MEDLINE, MEDLINE In-Process, PsycInfo, and Business Source Complete to identify empirical studies of empathy involving health care personnel in English-language publications up until April 20, 2021, covering the first five decades of research on empathy in health care (1971-2021).STUDY DESIGN:We performed a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines.DATA COLLECTION/EXTRACTION METHODS:Title and abstract screening for study eligibility was followed by full-text screening of relevant citations to extract study information (e.g., study design, sample size, empathy measure used, empathy assessor, intervention type if applicable, other variables evaluated, results, and significance). We classified study predictors and outcomes into categories, calculated descriptive statistics, and produced tables to summarize findings.PRINCIPAL FINDINGS:Of the 2270 articles screened, 455 reporting on 470 analyses satisfied the inclusion criteria. We found that most studies have been survey-based, cross-sectional examinations; greater empathy is associated with better clinical outcomes and patient care experiences; and empathy predictors are many and fall into five categories (provider demographics, provider characteristics, provider behavior during interactions, target characteristics, and organizational context). Of the 128 intervention studies, 103 (80%) found a positive and significant effect. With four exceptions, interventions were educational programs focused on individual clinicians or trainees. No organizational-level interventions (e.g., empathy-specific processes or roles) were identified.CONCLUSIONS:Empirical research provides evidence of the importance of empathy to health care outcomes and identifies multiple changeable predictors of empathy. Training can improve individuals' empathy; organizational-level interventions for systematic improvement are lacking.

Background Across England, 12% of all improving access to psychological therapy (IAPT) appointments are missed, and on average around 40% of first appointments are not attended, varying significantly around the country. In order to intervene effectively, it is important to target the patients who are most likely to miss their appointments. Objective This research aims to develop and test a model to predict whether an IAPT patient will attend their first appointment. Methods Data from 19 adult IAPT services were analysed in this research. A multiple logistic regression was used at an individual service level to identify which patient, appointment and referral characteristics are associated with attendance. These variables were then used in a generalised linear mixed effects model (GLMM). We allow random effects in the GLMM for variables where we observe high service to service heterogeneity in the estimated effects from service specific logistic regressions. Findings We find that patients who self-refer are more likely to attend their appointments with an OR of 1.04. The older a patient is, the fewer the number of previous referrals and consenting to receiving a reminder short message service are also found to increase the likelihood of attendance with ORs of 1.02, 1.10, 1.04, respectively. Conclusions Our model is expected to help IAPT services identify which patients are not likely to attend their appointments by highlighting key characteristics that affect attendance. Clinical implications This analysis will help to identify methods IAPT services could use to increase their attendance rates.

Introduction. There are growing concerns about the impact of the COVID-19 pandemic on mental health. With government-imposed restrictions as well as a general burden on healthcare systems, the pandemic has the potential to disrupt the access to, and delivery of, mental healthcare. Ultimately, this could potentially lead to unmet needs of individuals requiring mental health support. Methods. Electronic healthcare records from primary care psychological therapy services (Improving Access to Psychological Therapy) in England were used to examine changes in access to mental health services and service delivery during early stages of the COVID-19 pandemic. A cross-sectional, descriptive timeseries was conducted using data from 1st January 2019 to 24th May 2020 across five NHS trusts to examine patterns in referrals to services (n = 171,823) and appointments taking place (n = 865,902). Results. The number of patients accessing mental health services dropped by an average of 55% in the 9 weeks after lockdown was announced, reaching a maximum reduction of 74% in the initial 3 weeks after lockdown in the UK. As referrals began to increase again, there was a relatively faster increase in referrals from Black, Asian, and ethnic minority groups as well an increase in referrals from more densely populated areas. Despite a reduction in access, service providers adapted to infection control guidance by rapidly shifting to remote delivery of care. Interpretation. Services were able to rapidly adapt to provide continuity of care in mental healthcare. However, patients accessing services reduced dramatically, potentially placing a future burden on service providers to treat a likely backlog of patients in addition to a possible excess of patients as the long-term consequences of the pandemic become more apparent. Despite the observational nature of the data, which should be noted, the present study can inform the planning of service provision and policy.

In this paper we explore the effect of the orientation of the main crystallographic axes in relaxor-ferroelectric single crystals (SCs) on the piezoelectric anisotropy and squared figures of merit of 2–2 parallel-connected SC/auxetic polymer composites. The single-crystal component for the composite is chosen from the perovskite-type solid solutions with compositions near the morphotropic phase boundary and poled along the perovskite unit-cell [011] direction (mm 2 symmetry of domain-engineered SCs). The orientation of the main crystallographic axes in the single-crystal component is observed to strongly influence the piezoelectric coefficients $$d_{3j}^{*}$$ , squared figures of merit $$d_{3j}^{*}$$ $$g_{3j}^{*}$$ , electromechanical coupling factors $$k_{3j}^{*}$$ , and hydrostatic analogs of these parameters of the 2–2 composite. Inequalities $$| {d_{33}^{*} /d_{3f}^{*} } | > 5$$ and $$| {k_{33}^{*} /k_{3f}^{*} } | > 5$$ (f = 1 and 2) are achieved at specific orientations of the main crystallographic axes due to the significant anisotropy of the elastic and piezoelectric properties of the single-crystal component. The use of an auxetic polyethylene (a polymer component with a negative Poisson’s ratio) leads to a significant increase in the hydrostatic parameters. Particular advantages of such composites over conventional ceramic/polymer composites are taken into account for transducer, hydroacoustic, energy harvesting, and other applications.

This paper describes the manufacture of structural composites incorporating piezoelectric fibres which are finding interest in applications such as shape-changing applications, sensors to detect mechanical strain or vibration and energy harvesting. In this paper preliminary results are presented for a simple cantilever structure consisting of piezoelectric fibres with planar electrodes that are co-cured within a carbon fibre reinforced plastic (CFRP). Processing methods to embed functional fibres are described along with characterization of the piezoelectric and mechanical properties of the resulting material.

The need for reduced power requirements for small electronic components, such as wireless sensor networks, has prompted interest in recent years for energy harvesting technologies capable of capturing energy from broadband ambient vibrations. Encouraging results have been reported for an arrangement of piezoelectric layers attached to carbon fiber / epoxy laminates which possess bistability by virtue of their specific asymmetric stacking sequence. The inherent bistability of the underlying structure is exploited for energy harvesting since a transition from one stable configuration to another, or 'snap-through', is used to repeatedly strain the surface-bonded piezoelectric and generate electrical energy. Existing studies, both experimental and modelling, have been limited to simple geometric laminate shapes, restricting the scope for improved energy harvesting performance by limiting the number of design variables. In this paper we present an analytical model to predict the static shapes of laminates of any desired profile, validated experimentally using a digital image correlation system. Good accuracy in terms of out-of-plane displacements (5-7%) are shown in line with existing square modelling results. The static model is then mapped to a dynamics model and used to compare results against an experimental study of the harvesting performance of an example arbitrary geometry piezoelectric-laminate energy harvester.

The use of bistable laminates is a potential approach to realize more broadband piezoelectric based energy harvesting systems. Based on the experimental time series of a bistable laminate plate we have examined its dynamic response. The system was subjected to harmonic excitations showing the existence of single well and snap-through vibrations of periodic and chaotic character. To identify the dynamics of the system response we examine the frequency spectrum, phase portraits and multi-scaled entropy. It is observed that the composite multiscale entropy analysis can be used to identify complexity within the dynamic response successfully.

This paper presents analytical modelling and experimental characterisation of an arrangement of bistable composite plates with bonded piezoelectric elements to perform broadband vibration-based energy harvesting from ambient mechanical vibrations. These bistable devices have the potential to exhibit improved power generation compared to conventional resonant systems by exploiting nonlinear modes of oscillation driven by a ‘snap-through’ mechanism. Snap-through behaviour is shown to lead to higher average power outputs over a much broader frequency bandwidth than a resonant device. The conditions which yield these snap-through modes are investigated in terms of drive frequency and amplitude of vibration, revealing the emergence of intermittent and continuous snap-through modes for higher amplitude oscillations. These modes are found to widen the half-power bandwidth from 7Hz for linear oscillations (106mW for 4g peak acceleration) to 22Hz for high amplitude snap-through behaviour (244mW for 10g peak acceleration).

The need to power small electronic components, such as wireless sensor networks, has prompted interest in energy harvesting technologies capable of generating electrical energy from ambient vibrations. There has been a particular focus on piezoelectric materials and devices due to the simplicity of the mechanical to electrical energy conversion and their high strain energy densities compared to electrostatic and electromagnetic equivalents. This paper describes research on an arrangement of piezoelectric elements attached to a bistable asymmetric laminate to understand the dynamic response of the structure and power generation characteristics. The inherent bistability of the underlying structure is exploited for energy harvesting since 'snap-through' from one stable configuration to another is used to strain the piezoelectric materials bonded to the laminate and generate piezoelectric energy. Using high speed digital image correlation, a variety of dynamic modes of oscillation are identified in the bistable harvester. The sensitivity of such vibrational modes to changes in frequency and amplitude are investigated. Electrical power outputs are measured for repeatable snap-through events and are correlated with the modes of oscillation. The typical power generated is approximately 25mW and compares well with the needs of typical wireless senor node applications.

In this paper effect of the orientation of the main crystallographic axes on the piezoelectric anisotropy and hydrostatic parameters of 2–2 parallel-connected single crystal (SC) / auxetic polymer composites is analysed. SCs are chosen among the perovskite-type relaxor-ferroelectric solid solutions of (1 – x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 and xPb(In1/2Nb1/2)O3–yPb(Mg1/3Nb2/3)O3–(1 – x – y)PbTiO3. The SC layers in a composite sample are poled along the perovskite unit-cell [011] direction and characterised by mm2 symmetry. The orientation of the main crystallographic axes in the SC layer is observed to strongly influence the effective piezoelectric coefficients d*3j, g*3j, squared figured of merit d*3j g*3j, electromechanical coupling factors k*3j (j = 1, 2 and 3), and hydrostatic analogs of these parameters of the 2–2 composite. A comparison of values of d*3j g*3j was first carried out at d*31 ≠ d*32 in a wide range of orientations and volume-fraction. Large values of the effective parameters and inequalities | d*33 / d*3f | > 5 and | k*33 / k*3f | > 5 (f = 1 and 2) are achieved at specific orientations of the main crystallographic axes due to the anisotropy of elastic and piezoelectric properties of the SC component. The use of an auxetic polyethylene with a negative Poisson’s ratio leads to a significant increase in the hydrostatic parameters of the 2–2 composite. Particular advantages of the studied composites over the conventional ceramic / polymer composites are taken into account for transducer, hydroacoustic and energyharvesting applications.

Under certain conditions asymmetric composite laminates can have a bistable response to mechanical loading. A transition between the two stable states provides opportunities to produce large deflections or shape changes from relatively low energy inputs that do not need to be maintained to sustain a specific shape. Such laminates are attracting interest in aerospace applications, deployable structures and energy harvesting. Accurate modelling predictions of bistable laminate shapes has proven challenging, in part due to uncertainties in geometry, material properties and the operating environment of the laminates. In this paper a detailed sensitivity analysis of the influence of each of these properties on laminate curvature is undertaken and demonstrates that bistable laminates are most sensitive to uncertainties in the Young’s moduli, thermal expansion coefficients, ply thickness and the temperature change from the elevated cure temperature. Accurate characterisation of these properties and quality control during manufacture can reduce the discrepancies between analytical models and experimental results and allow the models to be used as viable tools for the design of bistable laminates. It is also shown that laminates are highly sensitive to moisture absorption and temperature changes, especially when changes in material properties due to temperature were included in the modelling.

The continuing need for reduced power requirements for small electronic components, such as wireless sensor networks, has prompted renewed interest in recent years for energy harvesting technologies capable of capturing energy from ambient vibrations. A particular focus has been placed on piezoelectric materials and devices due to the simplicity of the mechanical to electrical energy conversion and their high strain energy densities compared to electrostatic and electromagnetic equivalents. In this paper an arrangement of piezoelectric layers attached to a bistable asymmetric laminate is investigated experimentally to understand the dynamic response of the structure and power generation characteristics. The inherent bistability of the underlying structure is exploited for energy harvesting since a transition from one stable configuration to another, or "snap-through", is used to repeatedly strain the surface bonded piezoelectric and generate electrical energy. This approach has been shown to exhibit high levels of power extraction over a wide range of vibrational frequencies. Using high speed digital image correlation, a variety of dynamic modes of oscillation are identified in the harvester. The sensitivity of such modes to changes in vibration frequency and amplitude are investigated. Power outputs are measured for repeatable snap-through events of the device and are correlated with the measured modes of oscillation. The typical power generated is approximately 3.2 mW, comparing well with the needs of typical wireless senor node applications.

Energy harvesting devices based on a piezoelectric material attached to asymmetric bistable laminate plates have been shown to exhibit high levels of power extraction over a wide range of frequencies. This paper optimizes for the design of bistable composites combined with piezoelectrics for energy harvesting applications. The electrical energy generated during state-change, or “snap-through,” is maximized through variation in ply thicknesses and rectangular laminate edge lengths. The design is constrained by a bistability constraint and limits on both the magnitude of deflection and the force required for the reversible actuation. Optimum solutions are obtained for differing numbers of plies and the numerical investigation results are discussed.

Asymmetric composite laminates can have a bistable response to loading. The potentially large structural deformations which can be achieved during snap-through from one stable state to another with small and removable energy input make them of interest for a wide range of engineering applications. After 30 years of research effort the shapes and response to applied loads of laminates of general layup can be quantitatively predicted. With attention switching to the incorporation of bistable laminates for practical applications, tools for the design and optimisation of actuated bistable devices are desirable. This thesis describes the analytical and experimental studies undertaken to develop novel modelling and optimisation techniques for the design of actuated asymmetric bistable laminates. These structures are investigated for practical application to morphing structures and the developing technology of piezoelectric energy harvesting. Existing analytical models are limited by the need for a numerical solver to determine stable laminate shapes. As the problem has multiple equilibria, convergence to the desired solution cannot be guaranteed and multiple initial guesses are required to identify all possible solutions. The approach developed in this work allows the efficient and reliable prediction of the stable shapes of laminates with off-axis ply orientations in a closed form manner. This model is validated against experimental data and finite element predictions, with an extensive sensitivity study presented to demonstrate the effect of uncertainty and imperfections in the laminate composition. This closed-form solution enables detailed optimisation studies to tailor the design of bistable devices for a range of applications. The first study considers tailoring of the directional stiffness properties of bistable laminates to provide resistance to externally applied loads while allowing low energy actuation. The optimisation formulation is constrained to guarantee bistability and to ensure a useful level of deformation. It is demonstrated that ‘cross-symmetric’ layups can provide stiffness in an arbitrary loading direction which is five times greater than in a chosen actuation direction.

This paper presents a unique arrangement of bistable composite plates with piezoelectric patches bonded to its surface to perform broadband vibration-based energy harvesting from ambient mechanical vibrations. These bistable nonlinear devices have been shown to have improved power generation compared to conventional resonant systems and can be designed to occupy smaller volumes than bistable magnetic cantilever systems. This paper presents the results of an optimization study of bistable composites that are capable of generating greater electrical power from a smaller space by discovering the correct geometric configuration for energy harvesting. Optimum solutions are investigated in a series of design parameter studies intended to reveal the complex interactions of the physical constraints and design requirements. The proposed approach considers the optimal choice of device aspect ratio, thickness, laminate stacking sequence, and piezoelectric surface area. Increased electrical output is found for geometries and piezoelectric configurations which have not been considered previously.

This paper presents an arrangement of bistable composite plates with bonded piezoelectric patches to perform broadband vibration-based energy harvesting from ambient mechanical vibrations. These bistable nonlinear devices have the potential to exhibit improved power generation compared to conventional resonant systems and can be designed to occupy smaller volumes than bistable magnetic cantilever systems. In this paper we initially present the results of an optimization study to generate greater electrical power by discovering the correct geometric configuration for energy harvesting based on the static states of the device. The results consider the optimal choice of device aspect ratio, laminate thickness, laminate stacking sequence, and piezoelectric surface area. Increased electrical output is found for geometries and piezoelectric configurations which have not been considered previously. This study is then extended to include dynamic considerations of both the static shapes and the snap-through transition. Optimum designs are shown to be sensitive to the vibration pattern that is being harvested. The optimum geometric configurations based on the static analysis alone are not optimal under all dynamic conditions.

This paper presents an arrangement of bistable composites combined with piezoelectrics for broadband energy harvesting of ambient vibrations. These non-linear devices have improved power generation over conventional resonant systems and can be designed to occupy smaller volumes than magnetic cantilever systems. This paper presents results based on optimization of bistable composites that enables improved electrical power generation by discovering the optimal configurations for harvesting based on the statics of the device. The optimal device aspect ratio, thickness, stacking sequence, and piezoelectric area are considered. Increased electrical output is found for geometries and piezoelectric configurations, which have not been considered previously.

Abstract:  Asymmetric laminates are known to exhibit two stable cylindrical states and one unstable saddle state. Such bistability has attracted attention in aerospace applications because of the potential low energy requirement to achieve a large deflection or change in shape. This paper presents experimental observations of a generic asymmetric [−30/60] laminate with and without piezoelectric actuation and compares against both energy‐based analytical and finite element (FE) models. It is observed that the analytical model offers a qualitative understanding of bistable behaviour, degree of curvature and overall shape but is unable to model the distinctive curvature changes near the boundaries which can be captured by the FE model. The investigation also presents the use of piezoelectric actuation to achieve snap‐through in both analytical and FE models, which is compared and validated with experimental characterisation.

Asymmetric composite laminates can have a bistable response to mechanical loading. The large deflections that can be achieved by snap-through from one stable state to another, along with a need for small and removable energy input, make them of interest for a wide range of engineering applications. After 30 years of research efforts the shapes and response to applied strains of laminates of general layup have been well characterized. More recently, with the development of smart actuators, the design and application of bistable laminates has been considered. This paper presents an optimization technique for the design of bistable laminates enabled by an analytical solution for an asymmetric laminate design. The optimization formulation maximizes the bending stiffness in the direction of known loading condition while the bending stiffness in the direction of snap-through is minimized. A minimum deflection requirement is applied as a constraint. The design problem has multiple local optima, with the global optimum not intuitively obvious from the problem definition, differing from the typical high-deflection cross-ply solution.