Multiple motor-unit muscle models for the design of FES systems

Many functional electrical stimulation (FES) controllers have been developed using a simulation approach, the performance of these controllers depends on the muscle model accuracy. Realistic models of neuro-musculoskeletal systems can provide a safe and convenient environment for the design and evaluation of FES controllers. A typical FES system consists of FES controller, an electrical stimulator, electrodes and sensors.During FES, the stimulation level can change in a continuous fashion such that different motor-units are recruited at different muscle lengths and at different times. Furthermore, it is also not accurate to use the instantaneous length as input to the force-length relationship in dynamic (non-isometric) situations. Although instantaneous CE length is commonly used in FES control studies, empirical data from the literature were reviewed and it was concluded that the CE length at initial recruitment is a key parameter influencing total muscle force. The author presents a new multiple motor-unit Hill-type muscle model that accounts for different motor units being recruited at different CE lengths and different times. Hence the model can account for a continuously changing recruitment level whilst using the individual motor unit lengths at initial recruitment as input to the force-length relationship. Moreover, the model is capable of modelling fatigue and force enhancement & depression for the individual motor-units (i.e. the recruitment and time history effects). The model can also take account of the different force-length and force-velocity relationships for different fibre types by modelling these properties for the individual motor-units.The new multiple motor-unit model is described in detail, implemented and tested in Matlab. Open-loop simulation protocols are made on single/multiple motor-unit models using different CE lengths for the force-length relationship; on single/multiple motor-unit fatigue sub-models; and on single/ multiple motor-unit force enhancement & depression sub-models.A general model that can be used to represent all relevant models from the literature was developed. This model can also be used to build new models at different levels of complexity. Such a “General Model” could be used to study the effect of model complexity on FES controller design so that appropriate trade-offs between model complexity and accuracy could be determined. Results, limitations and possible future work are discussed

The Most Common Comorbidities in Dandy-Walker Syndrome Patients: A Systematic Review of Case Reports.

OBJECTIVE: Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities. METHODS: Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports. RESULTS: Diagnosis was most often set in 12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability. CONCLUSION: The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years

Communicable Diseases Prioritized for Surveillance and Epidemiological Research: Results of a Standardized Prioritization Procedure in Germany, 2011

To establish strategic priorities for the German national public health institute (RKI) and guide the institute's mid-term strategic decisions, we prioritized infectious pathogens in accordance with their importance for national surveillance and epidemiological research.We used the Delphi process with internal (RKI) and external experts and a metric-consensus approach to score pathogens according to ten three-tiered criteria. Additional experts were invited to weight each criterion, leading to the calculation of a median weight by which each score was multiplied. We ranked the pathogens according to the total weighted score and divided them into four priority groups.., Respiratory syncytial virus or Hantavirus) indicate a possible under-recognised importance within the current German public health framework. A process to strengthen respective surveillance systems and research has been started. The prioritization methodology has worked well; its modular structure makes it potentially useful for other settings

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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