CFD simulation of an industrial spiral refrigeration system

This is the final version. Available on open access from MDPI via the DOI in this recordIn the food industry, heating and cooling are key processes where CFD can play an important role in improving quality, productivity and reducing energy costs. Cooling products after baking is crucial for storage and transportation; the product has to be cooled efficiently to a specified temperature (often to fulfill regulatory requirements) whilst preserving its quality. This study involves the analysis of spiral cooling refrigerators used in cooling food products, in this case, Cornish Pasties. Three separate sets of CFD models were developed and validated against experimental data taken in the laboratory and measurements taken in use in industry. In the first set of models a full CFD model was developed of a refrigeration spiral including the pasties, and used to study the heat transfer from the products to the air. Further simulations were carried out on individual pasties to explore the pasty cooling and heat transfer to the air in more detail, with the pasty geometry being determined from MRI scans. In the final set of simulations, Image Based Meshing (IBM) was used to determine the interior structure of the pasty and develop a full heat conduction model of the interior, which was compared with separate laboratory experiments using jets of cold air to cool the pasty. In all cases, good agreement was obtained between the CFD results and experimental data, whilst the CFD simulations provide valuable information about the air flows and cooling in the industrial system.Innovate U

Attachment-security priming attenuates amygdala activation to social and linguistic threat

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.A predominant expectation that social relationships with others are safe (a secure attachment style), has been linked with reduced threat-related amygdala activation. Experimental priming of mental representations of attachment security can modulate neural responding, but the effects of attachment-security priming on threat-related amygdala activation remains untested. Using functional magnetic resonance imaging, the present study examined the effects of trait and primed attachment security on amygdala reactivity to threatening stimuli in an emotional faces and a linguistic dot-probe task in 42 healthy participants. Trait attachment anxiety and attachment avoidance were positively correlated with amygdala activation to threatening faces in the control group, but not in the attachment primed group. Furthermore, participants who received attachment-security priming showed attenuated amygdala activation in both the emotional faces and dot-probe tasks. The current findings demonstrate that variation in state and trait attachment security modulates amygdala reactivity to threat. These findings support the potential use of attachment security-boosting methods as interventions and suggest a neural mechanism for the protective effect of social bonds in anxiety disorders

A three-dimensional finite element analysis of the human hip

This is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge) via the DOI in this record.Athree-dimensional hip model was created from the MRI scans of one human subject based on constructing the entire pelvis and femur. The ball and socket joint was modelled between the hip’s acetabulum and the femoral head to analysethe multiaxial loads applied in the hip joint. The three key ligaments that reinforce the external surface of the hip to help to stabilisethe joint were also modelledwhich are the iliofemoral , the pubofemoral andischiofemoral ligaments. Each of these ligaments wraps around the joint connection to form a seal over the synovial membrane, a line of attachment around the head of the femur. This model was tested for different loading and boundary conditions to analysetheir sensitivitieson the cortical andcancellous tissues of the human hip bones. The outcomes of a one-legged stance finite element analysis revealed that the maximum of 0.056 mm displacement occurred. The stress distribution varied across the model which the majority occurring in the cortical femurand dissipating through the cartilage. The maximum stress value occurring in the joint was 110.1 MPa, which appeared at thefree end of the proximal femur.This developed finite element model was validated againstthe literature data to be used as anasset for further research in investigating new methods of total hip arthroplasty, to minimisethe recurrence of dislocations and discomfort in the hip joint, as well as increasing the range of movement available to a patient after surgery

The role of the lateral prefrontal cortex and anterior cingulate in stimulus–response association reversals

Many complex tasks require us to flexibly switch between behavioral rules, associations, and strategies. The prefrontal cerebral cortex is thought to be critical to the performance of such behaviors, although the relative contribution of different components of this structure and associated subcortical regions are not fully understood. We used functional magnetic resonance imaging to measure brain activity during a simple task which required repeated reversals of a rule linking a colored cue and a left/right motor response. Each trial comprised three discrete events separated by variable delay periods. A colored cue instructed which response was to be executed, followed by a go signal which told the subject to execute the response and a feedback instruction which indicated whether to ‘‘hold’’ or ‘‘f lip’’ the rule linking the colored cue and response. The design allowed us to determine which brain regions were recruited by the specific demands of preparing a rule contingent motor response, executing such a response, evaluating the significance of the feedback, and reconfiguring stimulus–response (SR) associations. The results indicate that an increase in neural activity occurs within the anterior cingulate gyrus under conditions in which SR associations are labile. In contrast, lateral frontal regions are activated by unlikely/unexpected perceptual events regardless of their significance for behavior. A network of subcortical structures, including the mediodorsal nucleus of the thalamus and striatum were the only regions showing activity that was exclusively correlated with the neurocognitive demands of reversing SR associations. We conclude that lateral frontal regions act to evaluate the behavioral significance of perceptual events, whereas medial frontal–thalamic circuits are involved in monitoring and reconfiguring SR associations when necessary

3D printing and its impact on anatomy teaching A case study of manufacturing human shoulder

This is the final versionAnatomical models played a significant role in medical science education and surgical preparation. In the last decade, using 3D printing techniques have been raised rapidly in different industrial sectors, including medical sciences for more detailed and customised models from an anatomical landmark (1, 2). The 3D printers can manufacture models in different scale with different materials while this approach can help the students to learn the anatomical structures when they are segmenting them using MRI or CT data and then manufacture them

Bilateral redundancy gain and callosal integrity in a man with callosal lipoma: a diffusion-tensor imaging study

We investigated whether abnormalities in the structural organisation of the corpus callosum in the presence of curvilinear lipoma are associated with increased facilitation of response time to bilateral stimuli, an effect known as the redundancy gain. A patient (A.J.) with a curvilinear lipoma of the corpus callosum, his genetically-identical twin, and age-matched control participants made speeded responses to luminant stimuli. Structural organisation of callosal regions was assessed with diffusion-tensor imaging. A.J. was found to have reduced structural integrity in the splenium of the corpus callosum and produced a large redundancy gain suggestive of neural summation

Value-based decision-making of cigarette and nondrug rewards in dependent and occasional cigarette smokers: An FMRI study

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordLittle is known about the neural functioning that underpins drug valuation and choice in addiction, including nicotine dependence. Following ad libitum smoking, 19 dependent smokers (smoked≥10/day) and 19 occasional smokers (smoked 0.5-5/week) completed a decision-making task. First, participants stated how much they were willing-to-pay for various amounts of cigarettes and shop vouchers. Second, during functional magnetic resonance imaging, participants decided if they wanted to buy these cigarettes and vouchers for a set amount of money. We examined decision-making behaviour and brain activity when faced with cigarette and voucher decisions, purchasing (vs not purchasing) cigarettes and vouchers, and “value signals” where brain activity correlated with cigarette and voucher value. Dependent smokers had a higher willingness-to-pay for cigarettes and greater activity in the bilateral middle temporal gyrus when faced with cigarette decisions than occasional smokers. Across both groups, the decision to buy cigarettes was associated with activity in the left paracingulate gyrus, right nucleus accumbens, and left amygdala. The decision to buy vouchers was associated with activity in the left superior frontal gyrus, but dependent smokers showed weaker activity in the left posterior cingulate gyrus than occasional smokers. Across both groups, cigarette value signals were observed in the left striatum and ventromedial prefrontal cortex. To summarise, nicotine dependence was associated with greater behavioural valuation of cigarettes and brain activity during cigarette decisions. When purchasing cigarettes and vouchers, reward and decision-related brain regions were activated in both groups. For the first time, we identified value signals for cigarettes in the brain.Biotechnology and Biological Sciences Research Council (BBSRC)Medical Research Council (MRC)Society for the Study of AddictionUniversity College London, National Institute of Health Research Biomedical Research Centr

Stress distribution of the tibiofemoral joint in a healthy versus osteoarthritis knee model using image-based three-dimensional finite element analysis

This is the final version. Available on open access from Springer via the DOI in this recordPurpose: Osteoarthritis (OA) is one of the most common pathological conditions to affect the human knee joint. In order to analyse the biomechanical causes and effects of OA, accessing the internal structures such as cartilage or the menisci directly is not possible. Therefore, computational models can be used to study the effects of OA on the stresses and strains in the joint and the susceptibility to deformations within the knee joint. Methods: In this study, a three-dimensional finite element (FE) model of a knee complex was constructed using MRI scans. Medical image processing software was used to create accurate geometries of bones, articular cartilages, menisci, patella, patella tendon and all the relevant ligaments. Finally, a 3D model of OA knee joint was created with a few changes to the cartilage. The cartilage was thinned, and the material properties were altered in order to simulate OA in the joint. 3D gait measurements were analysed to define loading and boundary conditions. Results: The developed model analysed the possibility of osteoarthritis. It was shown that the medial regions of cartilage layers and menisci in the knee joint sustain higher values of stress for OA conditions, while for the healthy knee, the stresses are more evenly distributed across the cartilage in the medial and lateral regions. Conclusion: The results suggest that any treatment for knee osteoarthritis should focus more on the medial region of the tibiofemoral cartilage in order not to cause degradation

The role of MRI and 3D modelling of the mandible in assisting personalised reconstructive surgery

This is the author accepted manuscript. The final version is available via the link in this recordPoster abstrac

Neural correlates of the inverse base rate effect

The inverse base rate effect (IBRE) is a nonrational behavioral phenomenon in predictive learning. Canonically, participants learn that the AB stimulus compound leads to one outcome and that AC leads to another outcome, with AB being presented three times as often as AC. When subsequently presented with BC, the outcome associated with AC is preferentially selected, in opposition to the underlying base rates of the outcomes. The current leading explanation is based on error-driven learning. A key component of this account is prediction error, a concept previously linked to a number of brain areas including the anterior cingulate, the striatum, and the dorsolateral prefrontal cortex. The present work is the first fMRI study to directly examine the IBRE. Activations were noted in brain areas linked to prediction error, including the caudate body, the anterior cingulate, the ventromedial prefrontal cortex, and the right dorsolateral prefrontal cortex. Analyzing the difference in activations for singular key stimuli (B and C), as well as frequency matched controls, supports the predictions made by the error-driven learning account