Classification of osteoarthritic and healthy cartilage using deep learning with Raman spectra.

Raman spectroscopy is a rapid method for analysing the molecular composition of biological material. However, noise contamination in the spectral data necessitates careful pre-processing prior to analysis. Here we propose an end-to-end Convolutional Neural Network to automatically learn an optimal combination of pre-processing strategies, for the classification of Raman spectra of superficial and deep layers of cartilage harvested from 45 Osteoarthritis and 19 Osteoporosis (Healthy controls) patients. Using 6-fold cross-validation, the Multi-Convolutional Neural Network achieves comparable or improved classification accuracy against the best-performing Convolutional Neural Network applied to either the raw or pre-processed spectra. We utilised Integrated Gradients to identify the contributing features (Raman signatures) in the network decision process, showing they are biologically relevant. Using these features, we compared Artificial Neural Networks, Decision Trees and Support Vector Machines for the feature selection task. Results show that training on fewer than 3 and 300 features, respectively, for the disease classification and layer assignment task provide performance comparable to the best-performing CNN-based network applied to the full dataset. Our approach, incorporating multi-channel input and Integrated Gradients, can potentially facilitate the clinical translation of Raman spectroscopy-based diagnosis without the need for laborious manual pre-processing and feature selection.

Multi-objective topology optimisation for acoustic porous materials using gradient-based, gradient-free, and hybrid strategies.

When designing passive sound-attenuation structures, one of the challenging problems that arise is optimally distributing acoustic porous materials within a design region so as to maximise sound absorption while minimising material usage. To identify efficient optimisation strategies for this multi-objective problem, several gradient, non-gradient, and hybrid topology optimisation strategies are compared. For gradient approaches, the solid-isotropic-material-with-penalisation method and a gradient-based constructive heuristic are considered. For gradient-free approaches, hill climbing with a weighted-sum scalarisation and a non-dominated sorting genetic algorithm-II are considered. Optimisation trials are conducted on seven benchmark problems involving rectangular design domains in impedance tubes subject to normal-incidence sound loads. The results indicate that while gradient methods can provide quick convergence with high-quality solutions, often gradient-free strategies are able to find improvements in specific regions of the Pareto front. Two hybrid approaches are proposed, combining a gradient method for initiation and a non-gradient method for local improvements. An effective Pareto-slope-based weighted-sum hill climbing is introduced for local improvement. Results reveal that for a given computational budget, the hybrid methods can consistently outperform the parent gradient or non-gradient method.

Incidence and outcome of anaphylaxis in cardiac surgical patients.

Introduction: Anaphylaxis is a rare but serious and potentially fatal complication of anesthesia. Little is known about the incidence and outcome of anaphylaxis in cardiac surgical patients, which we aimed to investigate. Methods: This was a 21-year retrospective study of cardiac surgical patients at Manchester Royal Infirmary, Manchester Foundation Trust, Manchester, UK. Results: A total of 19 cases of anaphylaxis were reported among 17,589 patients (0.108%) undergoing cardiac surgery. The majority (15/19) occurred before cardiopulmonary bypass (CPB), mostly during or within 30 min after the induction of anesthesia (10/19). Two occurred within 15 min of going onto CPB. Of these 17 cases, 11 were abandoned, and 6 proceeded. The severity of reactions in the patients who proceeded ranged from grade II to grade IV of the Ring and Messmer classification. Two cases occurred after the completion of surgery. All patients survived to 90 days. However, this did not appear to be related to CPB or protamine as most of the reactions occurred before CPB. Instead, the most common causative agents were gelofusine, antibiotics, muscle relaxants, and chlorhexidine. In 6 cases, surgery proceeded despite the anaphylaxis, in 11 cases the surgery was postponed, and in 2 cases the procedure had already been completed. Conclusion: As all patients survived, our results provide preliminary support for proceeding with surgery although we cannot speculate on the likely outcomes of patients who were postponed, had their surgery proceeded. Based on our data, the incidence of anaphylaxis in cardiac surgical patients may be 10-20 times higher than in the general surgical population.

Interactive effects of task load and music tempo on psychological, psychophysiological, and behavioural outcomes during simulated driving.

We examined the interactive effects of task load and music tempo on cognition, affect, cardiac response, and safety-relevant behaviour during simulated driving. Using a counterbalanced, within-subjects design, participants (N = 46) were exposed to fast-, slow-, and no-music conditions at high and low loads in a high-grade simulator. Task load had the most salient effect across a broad swath of variables. For core affect, the Load × Music Condition interaction showed that, under high load, affective arousal scores were higher in the fast-tempo condition vs. slow. A main effect of tempo emerged for the HRV index of SDNN, with fast-tempo music eliciting lower scores than both slow- and no-music conditions. Behavioural data showed a main effect of tempo for risk ratings, with fast-tempo music eliciting the highest scores for a traffic-light trigger. Our findings indicate that drivers in high-load, urban environments should exercise caution in their use of fast-tempo music. Practitioner summary: We examined the interactive effects of task load and music tempo in simulated driving (urban and highway). Cognition, mood, cardiac response, and driving behaviour were assessed. Participants exhibited more risky behaviours in response to fast-tempo music. Drivers should exercise caution in their use of up-tempo music in urban settings.

Comparison of heuristics and metaheuristics for topology optimisation in acoustic porous materials.

When designing sound packages, often fully filling the available space with acoustic materials is not the most absorbing solution. Better solutions can be obtained by creating cavities of air pockets, but determining the most optimal shape and topology that maximises sound absorption is a computationally challenging task. Many recent topology optimisation applications in acoustics use heuristic methods such as solid-isotropic-material-with-penalisation (SIMP) to quickly find near-optimal solutions. This study investigates seven heuristic and metaheuristic optimisation approaches including SIMP applied to topology optimisation of acoustic porous materials for absorption maximisation. The approaches tested are hill climbing, constructive heuristics, SIMP, genetic algorithm, tabu search, covariance-matrix-adaptation evolution strategy (CMA-ES), and differential evolution. All the algorithms are tested on seven benchmark problems varying in material properties, target frequencies, and dimensions. The empirical results show that hill climbing, constructive heuristics, and a discrete variant of CMA-ES outperform the other algorithms in terms of the average quality of solutions over the different problem instances. Though gradient-based SIMP algorithms converge to local optima in some problem instances, they are computationally more efficient. One of the general lessons is that different strategies explore different regions of the search space producing unique sets of solutions.

Psychological, psychophysiological and behavioural effects of participant-selected vs. researcher-selected music in simulated urban driving.

We investigated the effect of participant-selected (PSel) and researcher-selected (RSel) music on urban driving behaviour in young men (N = 27; Mage = 20.6 years, SD = 1.9 years). A counterbalanced, within-subjects design was used with four simulated driving conditions: PSel fast-tempo music, PSel slow-tempo music, RSel music and an urban traffic-noise control. The between-subjects variable of personality (introverts vs. extroverts) was explored. The presence of PSel slow-tempo music and RSel music optimised affective valence and arousal for urban driving. NASA Task Load Index scores indicated that the urban traffic-noise control increased mental demand compared to PSel slow-tempo music. In the PSel slow-tempo condition, less use was made of the brake pedal. When compared to extroverts, introverts recorded lower mean speed and attracted lower risk ratings under PSel slow-tempo music. The utility of PSel slow-tempo and RSel music was demonstrated in terms of optimising affective state for simulated urban driving.

The sensitivity of the Fatigue and Fitness Test for Teams (FFITT) to measure the demands of a rugby match.

Regular monitoring of players in a team can be a challenge because it is time consuming, expensive and impractical. The Fatigue and Fitness Test for Teams (FFITT) was developed to satisfy the demands of a practical monitoring protocol for frequent use in team sports. This study aimed to quantify the sensitivity of the FFITT and assess the practicality of implementing the FFITT in a rugby team. The FFITT was completed before and after three university 1st XV rugby union matches. The FFITT was sensitive to the demands of a rugby match in some individuals. Grouped results (n = 22 players) revealed a significant reduction in HRR60s of 7 beats post-match 3 (P = 0.002; ES = 0.52), which is greater than the 5 beats which constitute a meaningful change in fatigue and fitness. A significant reduction in SLJ of 11 cm was also observed post-match 3 (P = 0.04; ES = 0.69), which is less than the meaningful change (13 cm). On an individual level, meaningful changes occurred in SLJ distance in nine players, in HRR60s in 14 players and in both HRR60s and SLJ in three players. Descriptive analysis of the RTT-Q revealed that players experienced increased muscle soreness and reduced readiness-to-train post-match 1 and post-match 2. The FFITT could be successfully completed by the squad in 8 min during their warm-up. The FFITT satisfies both scientific principles and the coach's demands of a practical monitoring protocol for frequent use in the team sports setting.

The Fatigue and Fitness Test for Teams (FFITT): A practical option for monitoring athletes in a team as individuals.

We developed the Fatigue and Fitness Test for Teams (FFITT) to address the challenges of monitoring players in a team simultaneously. The test, which takes 8 min for the entire team, incorporates subjective measures of well-being (RTT-Q), and objective measures of the autonomic system (HRR60s) and neuromuscular function (SLJ). The aim of this study was to present the rationale for the FFITT as a novel athlete monitoring protocol and to measure the reliability of each component of the test. The internal consistency of the RTT-Q questions ranged from α = 0.69-0.92. All questions had an α > 0.83, with one exception of question 'Rate the well-being/stress your school/university/work is causing you to feel' which had an α = 0.69. The reliability of the HRR60s and SLJ was high (R = 0.92, and 0.91 respectively). The absolute typical error of measurement (TEM) of the SLJ was 8 cm and HRR60s was 3 beats. When expressed relatively the CVTEM of HRR60s was 8.4% and SLJ was 3.0%. Based on the TEM the HRR60s and SLJ could detect medium and large changes in fatigue and fitness. In absolute terms this equates to more than 5 bpm (HRR60s) and more than 13 cm (SLJ). The FFITT has the potential to satisfy both scientific principles and the coach's demands of a practical monitoring protocol for frequent use in a team.

Formulation of a covalently bonded hydroxyapatite and poly(ether ether ketone) composite.

Spinal fusion devices can be fabricated from composites based on combining hydroxyapatite and poly(ether ether ketone) phases. These implants serve as load-bearing scaffolds for the formation of new bone tissue between adjacent vertebrae. In this work, we report a novel approach to covalently bond hydroxyapatite and poly(ether ether ketone) to produce a novel composite formulation with enhanced interfacial adhesion between phases. Compared to non-linked composites (HA_PEEK), covalently linked composites (HA_L_PEEK), loaded with 1.25 vol% hydroxyapatite, possessed a greater mean flexural strength (170 ± 5.4 vs 171.7 ± 14.8 MPa (mean ± SD)) and modulus (4.8 ± 0.2 vs 5.0 ± 0.3 GPa (mean ± SD)). Although the mechanical properties were not found to be significantly different (p > 0.05), PEEK_L_HA contained substantially larger hydroxyapatite inclusions (100-1000 µm) compared to HA_PEEK (50-200 µm), due to the inherently agglomerative nature of the covalently bonded hydroxyapatite and poly(ether ether ketone) additive. Larger inclusions would expectedly weaken the HA_L_PEEK composite; however, there is no significant difference between the flexural modulus of poly(ether ether ketone) with respect to HA_L_PEEK (p = 0.13). In addition, the flexural modulus of HA_PEEK is significantly lower compared to poly(ether ether ketone) (p = 0.03). Ultimately, covalent linking reduces hydroxyapatite particulate de-bonding from the polymeric matrix and inhibits micro-crack development, culminating in enhanced transfer of stiffness between hydroxyapatite and poly(ether ether ketone) under loading.

Evolutionary squeaky wheel optimization: a new framework for analysis.

Squeaky wheel optimization (SWO) is a relatively new metaheuristic that has been shown to be effective for many real-world problems. At each iteration SWO does a complete construction of a solution starting from the empty assignment. Although the construction uses information from previous iterations, the complete rebuilding does mean that SWO is generally effective at diversification but can suffer from a relatively weak intensification. Evolutionary SWO (ESWO) is a recent extension to SWO that is designed to improve the intensification by keeping the good components of solutions and only using SWO to reconstruct other poorer components of the solution. In such algorithms a standard challenge is to understand how the various parameters affect the search process. In order to support the future study of such issues, we propose a formal framework for the analysis of ESWO. The framework is based on Markov chains, and the main novelty arises because ESWO moves through the space of partial assignments. This makes it significantly different from the analyses used in local search (such as simulated annealing) which only move through complete assignments. Generally, the exact details of ESWO will depend on various heuristics; so we focus our approach on a case of ESWO that we call ESWO-II and that has probabilistic as opposed to heuristic selection and construction operators. For ESWO-II, we study a simple problem instance and explicitly compute the stationary distribution probability over the states of the search space. We find interesting properties of the distribution. In particular, we find that the probabilities of states generally, but not always, increase with their fitness. This nonmonotonocity is quite different from the monotonicity expected in algorithms such as simulated annealing.

The alcohol hangover research group consensus statement on best practice in alcohol hangover research.

Alcohol-induced hangover, defined by a series of symptoms, is the most commonly reported consequence of excessive alcohol consumption. Alcohol hangovers contribute to workplace absenteeism, impaired job performance, reduced productivity, poor academic achievement, and may compromise potentially dangerous daily activities such as driving a car or operating heavy machinery. These socioeconomic consequences and health risks of alcohol hangover are much higher when compared to various common diseases and other health risk factors. Nevertheless, unlike alcohol intoxication the hangover has received very little scientific attention and studies have often yielded inconclusive results. Systematic research is important to increase our knowledge on alcohol hangover and its consequences. This consensus paper of the Alcohol Hangover Research Group discusses methodological issues that should be taken into account when performing future alcohol hangover research. Future research should aim to (1) further determine the pathology of alcohol hangover, (2) examine the role of genetics, (3) determine the economic costs of alcohol hangover, (4) examine sex and age differences, (5) develop common research tools and methodologies to study hangover effects, (6) focus on factor that aggravate hangover severity (e.g., congeners), and (7) develop effective hangover remedies.

Perspectives on occlusion and requirements for validation.

This paper discusses the limitations and potential of using an occlusion test to assess visual distraction and the suitability of an in-vehicle information system (IVIS) task for driving. This discussion was expanded from issues raised during a UK workshop on occlusion. The paper describes the research history and empirical foundations of occlusion. It describes some of the occlusion technology and applications for this procedure. Issues concerning the occlusion tasks and the duration and timing of occlusion are presented. The main part of this paper focuses on the priority research considerations for occlusion. The paper concludes with a description of some alternatives to occlusion and future research needs. It is concluded that the occlusion test has some promise, however the empirical basis for occlusion is lacking. If occlusion is to be developed as a metric to determine maximal safe visual distraction, substantial barriers remain.