Characterising the friction coefficient between rubber O-rings and a rigid surface under extreme pressures

Previous research into the friction behaviour of elastomers has typically focused on the effects of velocity, contact pressure, counter surface and lubrication on the coefficient of friction. O-ring type elastomer seals are common in many different industries. Friction plays a critical role during the setting and in service of these components. An experimental O-ring friction testing rig has been developed that can measure the effects of sliding speed and hydrostatic pressure on elastomer friction. Finite element analysis (FEA) packages can adopt fixed friction coefficients or ones that are pressure dependent. For the latter case, the dependence of the frictional behaviour is typically obtained from the instantaneous stress response at any given pressure and then related to the normal force response. The friction rig described in this paper uses industry standard dimensions for the O-ring gland, the pre-compression levels, extrusion gap size and pressure rating. The coefficient of friction is derived by dividing the measured friction force by the normal force, which was determined using an FEA modelling approach, as it could not be measured directly. Finally, a relationship between the frictional velocity and surface roughness is obtained in order to provide a frequency dependent Coefficient of Friction (CoF) that is easily translatable between surfaces

What Do Men Want from a Health Screening Mobile App? A Qualitative Study.

There is a lack of mobile app which aims to improve health screening uptake developed for men. As part of the study to develop an effective mobile app to increase health screening uptake in men, we conducted a needs assessment to find out what do men want from a health screening mobile app. In-depth interviews and focus group discussions were conducted with 31 men from a banking institution in Kuala Lumpur. The participants were purposely sampled according to their job position, age, ethnicity and screening status. The recruitment was stopped once data saturation was achieved. The audio-recorded interviews were transcribed verbatim and analyzed using thematic approach. Three themes emerged from the analysis and they were: content, feature and dissemination. In terms of the content, men wanted the app to provide information regarding health screening and functions that can assess their health; which must be personalized to them and are trustable. The app must have user-friendly features in terms of information delivery, ease of use, attention allocation and social connectivity. For dissemination, men proposed that advertisements, recommendations by health professionals, providing incentive and integrating the app as into existing systems may help to increase the dissemination of the app. This study identified important factors that need to be considered when developing a mobile app to improve health screening uptake. Future studies on mobile app development should elicit users' preference and need in terms of its content, features and dissemination strategies to improve the acceptability and the chance of successful implementation

The chicken IL-1 family: evolution in the context of the studied vertebrate lineage

The interleukin-1 gene family encodes a group of related proteins that exhibit a remarkable pleiotropy in the context of health and disease. The set of indispensable functions they control suggests that these genes should be found in all eukaryotic species. The ligands and receptors of this family have been primarily characterised in man and mouse. The genomes of most non-mammalian animal species sequenced so far possess all of the IL-1 receptor genes found in mammals. Yet, strikingly, very few of the ligands are identifiable in non-mammalian genomes. Our recent identification of two further IL-1 ligands in the chicken warranted a critical reappraisal of the evolution of this vitally important cytokine family. This review presents substantial data gathered across multiple, divergent metazoan genomes to unambiguously trace the origin of these genes. With the hypothesis that all of these genes, both ligands and receptors, were formed in a single ancient ancestor, extensive database mining revealed sufficient evidence to confirm this. It therefore suggests that the emergence of mammals is unrelated to the expansion of the IL-1 family. A thorough review of this cytokine family in the chicken, the most extensively studied amongst non-mammalian species, is also presented. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00251-014-0780-7) contains supplementary material, which is available to authorized users

Optimising Polyurethane/CNTs Piezoresistive Pressure Sensors by Varying the Modulus of the Polymer Matrix

Varying the elastic modulus of the thermoplastic polyurethane (TPU) matrix on the sensing behaviour of pressure sensors made from TPU/carbon nanotubes (CNTs) elastomeric composites was studied. Piezoresistive sensors have a wide range of applications in wearable devices such as smart shoe insoles. Compounds were prepared using different grades of TPU with various levels of hardness, ranging from 37 to 98 Shore A, using a melt extrusion technique. The percolation threshold of CNTs was about 2 wt%, with the best sensing performance being at a weight fraction above this, at 2.5 wt% CNTs. The elastomeric nanocomposites were characterised for their pressure sensing behaviour. Sensors were constructed by assembling the composite films and an interdigitated silver electrode, and their sensing properties were characterised using a voltage divider circuit under cyclical loading. This work evaluates the reference resistor-dependency, test frequency-dependency and the long-term stability under cyclic loading. The results indicate that the polymer modulus has a significant impact on the sensing performance and piezoresistive hysteresis value for each sensor. As the modulus increases, the hysteresis value between loading-unloading is reduced and the sensor displays a much more stable response during longer cyclical loading tests

A Pill for the Ill? Patients’ Reports of Their Experience of the Medical Encounter in the Treatment of Depression

Background Starting in the 1960s, a broad-based patients’ rights movement began to question doctors’ paternalism and to demand disclosure of medical information, informed consent, and active participation by the individual in personal health care. According to scholars, these changes contributed to downplay the biomedical approach in favor of a more patient-oriented perspective. The Swedish non-profit organization Consumer Association for Medicines and Health (KILEN) has offered the possibility for consumers to report their perceptions and experiences from their use of medicines in order to strengthen consumer rights within the health care sector. Methodology In this paper, qualitative content analysis was used to analyze 181 KILEN consumer reports of adverse events from antidepressant medications in order to explore patients’ views of mental ill health symptoms and the doctor-patient interaction. Principal Findings Overall, the KILEN stories contained negative experiences of the patients’ medical encounters. Some reports indicated intense emotional outrage and strong feelings of abuse by the health care system. Many reports suggested that doctors and patients had very different accounts of the nature of the problems for which the patient was seeking help. Although patients sought help for problems like tiredness and sleeplessness (often with a personal crisis of some sort as a described cause), the treating doctor in most cases was exceptionally quick in both diagnosing depression and prescribing antidepressant treatment. When patients felt they were not being listened to, trust in the doctor was compromised. This was evident in the cases when the doctor tried to convince them to take part in medical treatment, sometimes by threatening to withdraw their sick-listing. Conclusions Overall, this study suggests that the dynamics happening in the medical encounter may still be highly affected by a medical dominance, instead of a patient-oriented perspective. This may contribute to a questionable medicalization and/or pharmaceuticalization of depression.Funding Agencies|Stiftelsen Kempe-Carlgrenska Fonden||Lundgrenska Fonden||Stiftelsen Sigurd och Elsa Goljes Minne||Stiftelsen Lars Hiertas Minne||Elsa Lundberg och Greta Flerons||studier av lakemedelsbiverkan||</p