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The Long-term Outcomes of Sacral Neuromodulation for Fecal Incontinence: A Single Center Experience
No full textBackground: Sacral neuromodulation is an effective treatment for faecal incontinence. Objective: This study aimed to assess the long-term outcomes of sacral neuromodulation and establish the outcomes of patients with inactive devices.cDesign: This is an observational study of patients treated for more than 5 years. A positive outcome was defined as a >50% reduction in faecal incontinence episodes or improvement in a symptom severity score. Data was reviewed from a prospectively managed database. Settings: This study was conducted at a single tertiary referral centre.Patients: Data from 74 patients (72 female) were available at long-term follow up.Main Outcome Measures: Bowel diary, St. Mark’s incontinence score, and Manchester Health Questionnaire data were prospectively recorded at baseline, after peripheral nerve evaluation, and at last follow-up.Results: Patients were analysed in cohorts based on time since sacral neuromodulation implantation: Group 1: 5-10 years (n=20), Group 2: >10 years (n=35), and Group 3: inactive SNM devices (n=19). Median St. Mark’s incontinence score and Manchester Health Questionnaire improved from baseline to last follow-up in Group 1 (p=<0.05) and Group 2 (p=<0.05), but in Group 3 results returned to baseline levels at last follow-up. Similarly, weekly faecal incontinence episodes improved in both active device groups at last follow-up. However, in Group 3 incontinence episodes were no different from baseline (p=0.722). Despite active devices, faecal urgency episodes increased at last follow-up after more than 10 years since peripheral nerve evaluation (p=<0.05). Complete continence was reported by 44% of patients, and at least a 50% improvement in 77% with active devices.Limitations: This study is retrospective with some gaps in the available data at last follow-up.Conclusions: Sacral neuromodulation is an effective treatment for faecal incontinence in the long term, but all outcomes are adversely affected by device inactivity. Therefore, ongoing stimulation is required for continued benefit. <br/
The Long-term Outcomes of Sacral Neuromodulation for Fecal Incontinence: A Single Center Experience
No full textBackground: Sacral neuromodulation is an effective treatment for faecal incontinence. Objective: This study aimed to assess the long-term outcomes of sacral neuromodulation and establish the outcomes of patients with inactive devices.cDesign: This is an observational study of patients treated for more than 5 years. A positive outcome was defined as a >50% reduction in faecal incontinence episodes or improvement in a symptom severity score. Data was reviewed from a prospectively managed database. Settings: This study was conducted at a single tertiary referral centre.Patients: Data from 74 patients (72 female) were available at long-term follow up.Main Outcome Measures: Bowel diary, St. Mark’s incontinence score, and Manchester Health Questionnaire data were prospectively recorded at baseline, after peripheral nerve evaluation, and at last follow-up.Results: Patients were analysed in cohorts based on time since sacral neuromodulation implantation: Group 1: 5-10 years (n=20), Group 2: >10 years (n=35), and Group 3: inactive SNM devices (n=19). Median St. Mark’s incontinence score and Manchester Health Questionnaire improved from baseline to last follow-up in Group 1 (p=<0.05) and Group 2 (p=<0.05), but in Group 3 results returned to baseline levels at last follow-up. Similarly, weekly faecal incontinence episodes improved in both active device groups at last follow-up. However, in Group 3 incontinence episodes were no different from baseline (p=0.722). Despite active devices, faecal urgency episodes increased at last follow-up after more than 10 years since peripheral nerve evaluation (p=<0.05). Complete continence was reported by 44% of patients, and at least a 50% improvement in 77% with active devices.Limitations: This study is retrospective with some gaps in the available data at last follow-up.Conclusions: Sacral neuromodulation is an effective treatment for faecal incontinence in the long term, but all outcomes are adversely affected by device inactivity. Therefore, ongoing stimulation is required for continued benefit. <br/
In defence of existence questions
No full textDo numbers exist? Do properties? Do possible worlds? Do fictional characters? Many metaphysicians spend time and effort trying to answer these and other questions about the existence of various entities. These inquiries have recently encountered opposition: a group of philosophers, drawing inspiration from Aristotle, have argued that many or all of the existence questions debated by metaphysicians can be answered trivially, and so are not worth debating. Our task is to defend existence questions from the neo-Aristotelians' attacks
Toward large scale parallel computer simulation of viscoelastic fluid flow: A study of benchmark flow problems
No full textFollowed by our previous study, an OpenFOAM-based viscoelastic flow solver has been further validated through simulation of viscoelastic flow past a cylinder. The drag coefficients calculated by the Oldroyd-B model under the creeping flow in a range of Weissenberg (Wi) number are in good agreements with those reported in the literature. Using the linear Phan-Thien Tanner (L-PTT) model, time-dependent two-dimensional simulations of flow past cylinder have been carried out in a range of Wi number and Reynolds (Re) number, and revealed interesting cooperative effects of inertia and elasticity on the structural evolution of the wake behind the cylinder. The details of parallel computing strategy are analysed and discussed. The codes are evaluated for large scale parallel simulation of two-dimensional and three-dimensional contraction flow as well as two-dimensional flow past a cylinder. The key bottlenecks, which affect the scalability of parallel computing, are discussed
Day-ahead Prediction and Shaping of Dynamic Responses of the Demand at Bulk Supply Point
No full textApplication of URANS turbulence closure models to complex flows subjected to electromagnetic and other body forces
No full textThis paper considers the application of the Reynolds Averaged Navier-Stokes (RANS) approach to two types of electromagnetically influenced turbulent flows. The first is a fully-developed 2D channel flow with a magnetic field imposed in either the wall-normal direction (Hartmann Flow), or in the streamwise direction. The second is that of Rayleigh-Benard convection with a vertical magnetic field imposed. The turbulence is represented by a low-Re k-epsilon model which is tested with and without electromagnetic modifcations proposed by Kenjeres and Hanjalic (2000). The results show tha modifications lead to a dramatic reorganisation of the coherent structures in Rayleigh-Benard convection as the magnetic field strength is increased, but over-predict the damping of the turbulent shear stress in a simple channel flow
Value assessment and quantitative benefit-risk modelling of biosimilar infliximab for Crohn’s disease
No full textAim: Regulatory approval of biosimilars often depends on extrapolating evidence from one clinical indication to all of those of the originator biologic. We aimed to develop a quantitative benefit-risk analysis to assess whether the resulting increase in the uncertainty in the clinical performance of biosimilars (i.e. risk) may be countered by their lower pricing (benefit).Methods: A one-year decision-analytic model was developed for the biosimilar infliximab (Inflectra®) for Crohn’s disease. The perspective was that of the NHS in the UK and costs were valued to 2015/16. A hypothetical cohort of biologic-naïve patients with moderate-to-severe Crohn’s disease were simulated through the model. Immunogenicity to infliximab was a key modifier, influencing rates of non-response and infusion reactions. Net health benefit was estimated based on quality-adjusted life years (QALYs). A range of sensitivity analyses tested the robustness of the results and explored how the biosimilar price must respond to varying immunogenicity to remain the preferred option. Results: The base-case analysis predicted a positive incremental net health benefit of 0.04 (95% Central Range 0.00-0.09) favouring the biosimilar, based on 0.803 QALYs, and costs of £18,087 and £19,176 for biosimilar and originator, respectively. Two-way sensitivity analyses suggested that if 50% of patients developed antibodies, the value-based price of £410 per vial must be lower than that of the originator (£420), but remain higher than the actual market price (£378). Conclusions: The model supports the use of Inflecta® for Crohn’s disease in the UK, and provides a framework for the quantitative evaluation of biosimilars in the context of health technology assessment. Value-based pricing using this methodology could protect health systems from the potential risks of biosimilars where they are untested in the approved populations.<br/
Linking adaptation science to action to build food secure Pacific Island communities
No full textClimate change is a major threat to food security in Pacific Island countries, with declines in food production and increasing variability in food supplies already evident across the region. Such impacts have already led to observed consequences for human health, safety and economic prosperity. Enhancing the adaptive capacity of Pacific Island communities is one way to reduce vulnerability and is underpinned by the extent to which people can access, understand and use new knowledge to inform their decision-making processes. However, effective engagement of Pacific Island communities in climate adaption remains variable and is an ongoing and significant challenge. Here, we use a qualitative research approach to identify the impediments to engaging Pacific Island communities in the adaptations needed to safeguard food security. The main barriers include cultural differences between western science and cultural knowledge, a lack of trust among local communities and external scientists, inappropriate governance structures, and a lack of political and technical support. We identify the importance of adaptation science, local social networks, key actors (i.e., influential and trusted individuals), and relevant forms of knowledge exchange as being critical to overcoming these barriers. We also identify the importance of co-ordination with existing on-ground activities to effectively leverage, as opposed to duplicating, capacity
Storing renewables in the gas network: modelling of power-to-gas (P2G) seasonal storage flexibility in low carbon power systems
No full textThe power-to-gas (P2G) process, whereby excess renewable electrical energy is used to form hydrogen and/or synthetic natural gas that are injected, transported and stored in the gas network, has the prospect to become an important flexibility option for the seasonal storage of low-carbon electricity. This paper is the first to model and assess the potential of P2G when combined with gas seasonal storage operation accounting for the two networks’ characteristics and constraints (including the amount of hydrogen that can be blended with natural gas under different gas network conditions). Power system operation with P2G is analysed via a two-stage optimisation based on DC power flow in order to assess the gas production from otherwise curtailed renewables, also considering impact of P2G on short-term and long-term gas prices. Additionally, impact of P2G on gas network operation and its potentially required re-dispatch are evaluated with a steady-state gas flow model. Case studies conducted on the Great Britain gas and electrical transmission networks quantify benefits and limitations of the integrated usage of P2G with seasonal gas storage under different scenarios. The proposed model thus sets the fundamentals for further development of this emerging technology as a seasonal storage option in low-carbon power systems
Experimental and numerical investigations into electrochemical milling
No full textThis paper presents experimental and numerical investigations into electro-chemical (EC) milling of simple features such as slots and pockets. Preliminary experimental investigations into the machining of a slot enabled appropriate process parameters to be selected; these were then used to machine a simple square pocket and finally a pocket with a human-being shaped protrusion. These features were machined with tools having circular and square cross-sections. The pocket with the protrusion was machined with tool paths of zig–zag and contour-parallel type. The experimental results indicated that the machining accuracy depends upon, amongst other things, on the tool shape and process parameters. A boundary element of the EC machining process was used to predict the shape of the pockets and in most cases, the predicted shapes compared favourably with the actual machined features