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A three-dimensional mechano-electrochemical material model of mechanosensing hydrogels
No full textMechanotransduction is the initiation of an electrochemical signal as a result of mechanical stimuli. It is found predominately in biological tissue and its mechanisms are well documented. In the gel like tissues of the body, such as articular cartilage and intervertebral discs, mechanotransduction regulates matrix building and degrading processes as well as keeping the tissues adequately hydrated, both with the aim of minimizing degradation. The electrochemical responses to mechanical loading at constant volume of an inanimate hydrogel could assist in the understanding of these processes.
There is considerable evidence that the modulus of hydrated tissues and hydrogels depend explicitly on ionic concentration. By modeling the mechano-electrochemical relationship of a hydrogel, the coupling of the elastic and electrochemical energies can be quantified. In turn, the mechanisms that govern this phenomenon can be better understood. This study modifies the Flory-Rehner theory of gels, using material-specific experimental data as input. The results show up to a 11% difference in equilibrium swelling magnitude compared to the Flory-Rehner model. Furthermore, under isochoric deformation, an increase in electrical potential is shown with increasing shear strain, something which is not possible with conventional Flory-Rehner and Donnan theory. This aligns the continuum model presented here more closely with both experiment and microscopic theories. The mechanosensing capabilities as well as varying swelling responses in different solution concentrations highlight the models potential applications in both biological and technological settings
Telemedicine in the upper Amazon: Interplay with local health care practices
No full textThis article is based on the introduction of a telemedicine system in the jungles of northeastern Peru. The system was designed by a European consortium led by a Spanish polytechnic in cooperation with two universities in Lima and the Peruvian Ministry of Health. The purpose of the system was to improve health conditions by extending science-based medicine into a region with well-established traditional healing practices. The central analytical focus of this article is on the interplay between the public health care system, which used the telemedicine system, and local health care practices. The manner in which scientific medicine was delivered through information technology and public health care services is analyzed in terms of the health personnel\u27s activity, the local population \u27s conceptions of health, and the trajectories followed by patients seeking recovery. The author participated in the design of the second evaluation of the telemedicine system and acted as a participant observer in the regional hospital and peripheral clinics. In addition to interviewing health care staff from the study area, the author also met with traditional healers, and patients in the districts whether or not they were involved in the telemedicine project. New institutional theory provided the analytical framework for the interpretation of the observed behavior of the public health care staff, traditional healers, and potential patients. Empirically, this study describes the informal aspects of the functioning of the telemedicine system, and its partial mismatch with the definitions of health and illness employed by local communities and healers. An argument is made that people\u27s construction of their health, which is embedded in their normal patterns of action, should be identified, and then considered in the design, implementation, and evaluation of future telemedicine projects. This article problematizes an approach to telemedicine-based health development that is weakly accountable to local social contexts and their diversity
Preeclampsia and neurodevelopmental outcomes: Potential pathogenic roles for inflammation and oxidative stress?
No full textPreeclampsia (PE) is a common and serious hypertensive disorder of pregnancy that occurs in approximately 3–5% of first-time pregnancies and is a well-known leading cause of maternal and neonatal mortality and morbidity. In recent years, there has been accumulating evidence that in utero exposure to PE acts as an environmental risk factor for various neurodevelopmental disorders, particularly autism spectrum disorder and ADHD. At present, the mechanism(s) mediating this relationship are uncertain. In this review, we outline the most recent evidence implicating a causal role for PE exposure in the aetiology of various neurodevelopmental disorders and provide a novel interpretation of neuroanatomical alterations in PE-exposed offspring and how these relate to their sub-optimal neurodevelopmental trajectory. We then postulate that inflammation and oxidative stress, two prominent features of the pathophysiology of PE, are likely to play a major role in mediating this association. The increased inflammation in the maternal circulation, placenta and fetal circulation in PE expose the offspring to both prenatal maternal immune activation—a risk factor for neurodevelopmental disorders, which has been well-characterised in animal models—and directly higher concentrations of pro-inflammatory cytokines, which adversely affect neuronal development. Similarly, the exaggerated oxidative stress in the mother, placenta and foetus induces the placenta to secrete factors deleterious to neurons, and exposes the fetal brain to directly elevated oxidative stress and thus adversely affects neurodevelopmental processes. Finally, we describe the interplay between inflammation and oxidative stress in PE, and how both systems interact to potentially alter neurodevelopmental trajectory in exposed offspring
The Use of High Performance Liquid Chromatography for the Characterization of the Unfolding and Aggregation of Dairy Proteins
No full textHigh-performance liquid chromatography (HPLC) is routinely used to identify and characterize proteins. HPLC can help to understand protein aggregation processes in dairy products, which are induced by common industrial processing steps such as heat treatment. In this chapter, three complementary chromatographic methods are described, which are based on the principles of size exclusion and reversed-phase chromatography. These methods are used to determine the degree of denaturation and aggregation of proteins, and estimate the molecular weight of these aggregates
Tending the ‘Contested’ castle garden: Sowing seeds of feminist thought
No full textMedieval women are typically portrayed as secluded, passive agents within castle studies. Although the garden is regarded as associated with women there has been little exploration of this space within medieval archaeology. In this paper, a new methodological framework is used to demonstrate how female agency can be explored in the context of the lived experience of the medieval garden. In particular, this study adopts a novel approach by focusing on relict plants at some medieval castles in Britain and Ireland. Questions are asked about the curation of these plants and the associated social practices of elite women, including their expressions of material piety, during the later medieval period. This provides a way of questioning the ‘sacrality’ of medieval gardening which noblewomen arguably used as a devotional practice and as a means to further their own bodily agency through sympathetic medicine.This article was written as part of my Marie Skłodowska-Curie Fellowship 2017–
2019, entitled, ‘HeRSTORY’, based at the Department of Archaeology, University of
Reading, UK, where working with Professor Roberta Gilchrist I enjoyed unlimited
opportunity to tend and nurture my own ideas. This paper adds to her work on the
‘Contested Garden’. Thanks to Professor Madeline Gray and Gwynedd
Archaeological Trust for permission to use David Longley’s images of the Beaumaris
effigy. Dr Rachel Delman kindly shared the rosemary reference with me. To develop
further my research of relict plants studies at medieval castles, a new project ‘Sowing
Seeds of Interdisciplinary Wor
Assessing the Carbon Emission Driven by the Consumption of Carbohydrate-Rich Foods: The Case of China
No full textBackground: Carbohydrate-rich (CR) foods are essential parts of the Chinese diet.
However, CR foods are often given less attention than animal-based foods. The objectives of this
study were to analyze the carbon emissions caused by CR foods and to generate sustainable diets with
low climate impact and adequate nutrients. Methods: Twelve common CR food consumption records
from 4857 individuals were analyzed using K-means clustering algorithms. Furthermore, linear
programming was used to generate optimized diets. Results: Total carbon emissions by CR foods was
683.38g CO2eq per day per capita, accounting for an annual total of 341.9Mt CO2eq. All individuals
were ultimately divided into eight clusters, and none of the popular clusters were low carbon or
nutrient sufficient. Optimized diets could reduce about 40% of carbon emissions compared to the
average current diet. However, significant structural differences exist between the current diet and
optimized diets. Conclusions: To reduce carbon emissions from the food chain, CR foods should be a
research focus. Current Chinese diets need a big change to achieve positive environmental and health
goals. The reduction of rice and wheat-based foods and an increase of bean foods were the focus of
structural dietary change in CR food consumption.Natural Science Foundation of Guangdong Provinc
An examination of the neuroimmune interactions of amitriptyline, spinal cord stimulation and opioid therapy in human neuropathic pain
No full textBackground: The objective of this thesis was to explore mechanistic processes of amitriptyline, opioids and "Burst" spinal cord stimulation (SCS) for neuropathic pain in vivo. These three therapies are commonly employed for the management of neuropathic pain without a global agreed consensus with regard to mechanism of action. Whilst there is growing body of pre-clinical evidence supporting the concept that chronic neuropathic pain is associated with neuroimmune dysfunction and / or neuroinflammation, this has yet to be translated into the clinical domain. Epidural steroid injections have demonstrated an attenuation of neuroinflammation associated with a short-term reduction in pain. To demonstrate dynamic changes within the neuroimmune interface (neuronal-glia-immune cell communications) we compared the constituents of cerebrospinal fluid (CSF) before and after treatment with amitriptyline and Burst SCS. The mechanisms and side effects of opioids proposed for chronic pain are also related to neuroimmune interactions. Due to the fact many patients were taking opioids before enrolment, we compared the CSF of patients taking and not taking opioids prior to commencing the proposed interventional treatment. Not only would this provide data of confounding variables but give insight into opioid related phenomena and mechanisms. A more detailed characterisation of the effects of currently employed therapies may facilitate better stratification and phenotyping; as well as providing information which may enhance our understanding of the pathophysiology of neuropathic pain. Methods: This study involved taking cerebrospinal fluid samples before and after treatment and determining the cellular constituents of central peptides and immune cells. Patients were screened for neuropathic pain at outpatient clinics at St. James?s Hospital, Dublin and enrolled according to strict inclusion/exclusion criteria of the individual study. Lumbar radicular pain was the most common diagnosis for enrolled patients. Demographics and pains scores according to numerical rating scale (NRS) were recorded. After a baseline CSF sample the interventional treatment was commenced for 8 weeks. A second sample was subsequently taken after 8 weeks of treatment as well as outcome data. We compared the baseline and post intervention samples examining cellular data of T cells via flow cytometry, specific neuropeptides by ELISA and the proteome via Mass Spectrometry. In vitro work was also performed to examine the effect of amitriptyline on T cells directly. Results: In a cohort of patients with lumbar radicular pain who were deemed responders to amitriptyline, GO analysis identified immune system process as the most modulated proteins. This was associated with an attenuation of pro-inflammatory pathways, including the MAPK pathway identified by KEGG analysis. The chemokine eotaxin-1 was also significantly reduced in responders to amitriptyline. In-vitro work on T cells demonstrated an attenuation of the TH1/Th17 response and a modulation of other cytokine networks. This was largely in na?ve populations however postulating that peripheral and central actions of amitriptyline may differ. According to GO analysis proteins related to synapse assembly were the most modulated after Burst-SCS. This is consistent with neurophysiological data that suggests burst neuronal firing strengthens synaptic transmission and efficacy. Individual protein analysis also indicated that Burst SCS demonstrated potential supraspinal effects and modulation of immune effectors. GO analysis identified expression of proteins related to positive regulation of nervous system development and myeloid leucocyte activation in patients medicated with opioids. The largest decrease expression of proteins in the patients medicated with opioids related to neutrophil mediated immunity. Conclusion: Although effective, no treatment achieved full remission of symptoms in any patient. This would suggest that current therapies only target selective pathways involved in the pathophysiology of neuropathic pain. Although evidence of immuno-modulation was present with all therapies examined; this was not consistent. We have demonstrated that immune effectors or neuro-glial communications are likely contributory in the pathogenesis and attenuation of neuropathic pain. What is also evident was molecular evidence of neuroplasticity which involves many pathways and cells within the central nervous system. The chronicity of pain in humans is inherently complex but advances in technology with CSF analysis and neuroimaging in conjunction with sham/placebo-controlled trials will enable better phenotyping of patients and a better understanding of treatment mechanisms and the pathophysiology of neuropathic pain
3D modelling of concrete tunnel segmental joints and the development of a new bolt-spring model
No full textIn a segmental metro tunnel, it is widely observed that cracks, water leakage and other structural defects usually appear at segmental joint section of a smaller stiffness than main tunnel segment section. In this study, a 3D finite element analysis was conducted to simulate a typical concrete segmental joint explicitly using 3D continuum elements, and the performance of 3D continuum model was validated against laboratory tests available in literature. Since such continuum model may cost excessive computational time when a large-scale tunnel structure is analysed, a new bolt-spring model was developed to simplify the structural features of concrete segmental joint. In the bolt-spring model, the interaction between bolt and segment was modelled by a set of normal springs and shear springs: the stiffness of the normal springs is mainly determined by the bolt itself, whilst the shear springs take account of bolt-segment friction, interaction and shear resistance of the bolt. In the meanwhile, the interaction between two adjoining tunnel segments is explicitly modelled using contact elements. The proposed bolt-spring model is able to simulate the details of joint deformation and contact pressure between segments more realistically than previously available by conventional methods (e.g. continuous ring, beam-spring model (BSM)), where segment-segment interaction is not explicated modelled. Compared to the continuum model, the bolt-spring model saves up to 90% computational time without compromising numerical accuracy. Furthermore, this paper compared the mechanical behaviour of a concrete joint against that of a cast-iron one with particular emphasis on the development of different bolt-spring models
Mitigating ammonia and greenhouse gas emissions from stored cattle slurry using agricultural waste, commercially available products and a chemical acidifier.
No full textBovine slurry and its subsequent storage are significant sources of ammonia (NH3) and greenhouse gases (GHGs). Chemical acidification of manures has been shown to significantly reduce these emissions. Waste products, derived from food processing and on-farm practices, may be used as natural acidifiers. However, the efficacy of these products in reducing pH and any subsequent emissions is unknown. Commercially available slurry improvers or additives may also be a viable mitigation option; however, their effectiveness has yet to be quantified. This study investigated the efficacy and cost of a range of waste and commercial amendments and a chemical acidifier, ferric chloride (FeCl3), to identify the most effective amendment for NH3 and GHG emissions reduction. The majority of the waste amendments investigated reduced NH3 by between 2% and 67%. Methane (CH4) emissions were reduced only by spent brewers grain, sugarbeet molasses and grass silage effluent at the higher inclusions (i.e. amounts added), with reductions ranging from 15% to 70%. Carbon dioxide (CO2) emissions were significantly increased with the addition of waste amendments. Commercially available additives had little impact on emissions, with the exception of one treatment, which reduced CH4 by approximately 10%. Ferric chloride reduced NH3 emissions by 20% - 68%, CH4 by 6% - 65%, and CO2 by 6% - 38%, depending on the inclusion. All waste amendments had low marginal abatement costs ranging from - 0.46 to 0.88 kg-1 NH3 abated compared to FeCl3 and commercial amendments ( 1.80 to 231 kg-1 NH3). This incubation experiment demonstrated that a range of on farm and industry waste streams could be valorised to reduce NH3 emissions. However, many of these may result in higher CH4 and CO2 emissions due to input of labile carbon sources. Therefore, it is vital that a holistic analysis of the impact of waste streams on manure emissions to air and water is performed to assess the efficacy of these substances in ameliorating environmental impacts and avoiding possible pollution swapping.The author would like to thank the laboratory and field staff at Teagasc Johnstown Castle Wexford, for their assistance on the project. This work was funded by the Irish Department of Agriculture, Food and the Marine (Grant number RSF 13/S/430) and the Walsh scholarship programme
The relationship between training load and pain, injury and illness in competitive swimming: A systematic review
No full textThe full text of this article will not be available in ULIR until the embargo expires on the 09/01/2022Background
Research suggests that the frequency of training, combined with the repetitive motion involved in high volume swimming can predispose swimmers to symptoms of over-training. The prevention of pain, injury and illness is of paramount importance in competitive swimming in order to maximise a swimmer’s ability to train and perform consistently. A significant factor in the prevention of pain, injury or illness is the appropriate load monitoring and management practices within a training programme.
Objective
The purpose of this systematic review is to investigate the relationship between training load and pain, injury and illness in competitive swimmers.
Methods
The databases SPORTDiscus, CINAHL, Scopus, MEDLINE and Embase were searched in accordance with PRISMA guidelines. Studies were included if they reported on competitive swimmers and analysed the link between training load and either pain, injury or illness. The methodological quality and study bias were assessed using the Joanna Briggs Institute Critical Appraisal Checklist.
Results
The search retrieved 1,959 articles, 15 of which were included for review. The critical appraisal process indicated study quality was poor overall. Pain was the most explored condition (N = 12), with injury (N = 2) and illness (N = 1) making up the remaining articles. There was no evidence of an association between training load and pain, while there may be some evidence to suggest a relationship between training load and injury or illness.
Conclusions
The relationship between training load and pain, injury or illness is unclear owing to a host of methodological constraints. The review highlighted that youth, masters and competitive swimmers of a lower ability (e.g. club versus international) may need particular consideration when planning training loads. Winter periods, higher intensity sessions and speed elements may also need to be programmed with care. Monitoring practices need to be developed in conjunction with consensus guidelines, with the inclusion of internal training loads being a priority. Future research should focus on longitudinal prospective studies, utilising the session Rating of Perceived Exertion (sRPE) monitoring method and investigating the applicability of Acute/Chronic Workload Ratio (ACWR) and exponentially weighted moving average (EWMA). Improved methods and study design will provide further clarity on the relationship between load and pain, injury, and illness