Bioprocess applications of model-based estimation techniques

The last decade has seen the development of a number of approaches for estimating those variables which are difficult to measure on-line in industrial process situations. Whilst a range of techniques is available, a common element is the use of process knowledge in the form of a system model. In the case of bioprocess systems, although a large range of models has been presented in the literature, their use in estimation schemes on an industrial scale has been limited. A number of reasons can be identified for their low level of utilisation. Of particular significance is the uncertainty which exists in quantifying system performance and the process-model mismatch which inevitably results. The level of ‘pre-defined model’ uncertainty, together with the knowledge gained during the course of the fermentation, serves to dictate estimator structure. The paper considers a range of estimation strategies and contrasts, through industrial applications, their performance characteristics and utility.     

Patient source of learning about health technologies and ratings of trust in technologies used in their care

In order to design effective health technologies and systems, it is important to understand how patients learn and make decisions about health technologies used in their care. The objective of this study was to examine patients' source of learning about technologies used in their care and how the source related to their trust in the technology was used. Individual face-to-face and telephone interviews were conducted with 24 patients. Altogether, 13 unique sources of information about technology were identified and three major themes emerged: outside of the work system vs. inside the work system; when the health information was provided; the medium used. Patients used multiple sources outside of the healthcare work system to learn about technologies that will be used in their care. Results showed a relationship between learning about technologies from web sources and trust in technologies but no relationship between learning about technologies from healthcare providers and trust in technologies. STATEMENT OF RELEVANCE: The value of considering human attitudes about elements in health systems has been illustrated. This research shows a relationship between patient attitudes about medical technologies used in their care and healthcare work system design. Results show that patient attitudes are formed about technologies used in their care by sources within and outside of the sociotechnical work system.     

Role of Tyrosine Kinase Syk in Thrombus Stabilisation at High Shear

Understanding the pathways involved in the formation and stability of the core and shell regions of a platelet-rich arterial thrombus may result in new ways to treat arterial thrombosis. The distinguishing feature between these two regions is the absence of fibrin in the shell which indicates that in vitro flow-based assays over thrombogenic surfaces, in the absence of coagulation, can be used to resemble this region. In this study, we have investigated the contribution of Syk tyrosine kinase in the stability of platelet aggregates (or thrombi) formed on collagen or atherosclerotic plaque homogenate at arterial shear (1000 s⁻¹). We show that post-perfusion of the Syk inhibitor PRT-060318 over preformed thrombi on both surfaces enhances thrombus breakdown and platelet detachment. The resulting loss of thrombus stability led to a reduction in thrombus contractile score which could be detected as early as 3 min after perfusion of the Syk inhibitor. A similar loss of thrombus stability was observed with ticagrelor and indomethacin, inhibitors of platelet adenosine diphosphate (ADP) receptor and thromboxane A₂ (TxA₂), respectively, and in the presence of the Src inhibitor, dasatinib. In contrast, the Btk inhibitor, ibrutinib, causes only a minor decrease in thrombus contractile score. Weak thrombus breakdown is also seen with the blocking GPVI nanobody, Nb21, which indicates, at best, a minor contribution of collagen to the stability of the platelet aggregate. These results show that Syk regulates thrombus stability in the absence of fibrin in human platelets under flow and provide evidence that this involves pathways additional to activation of GPVI by collagen.     

Modelling and adaptive control of fed-batch penicillin fermentation

This paper describes a study to investigate the application of state estimation and parameter adaptive control in fed-batch fermentation for penicillin production. A model of the penicillin fermentation process is outlined and shown to be capable of matching industrial data. The penicillin mould biomass is controlled to a reference trajectory by applying self-tuning control to an estimate of biomass, obtained from measurements of carbon dioxide production rate and fermenter volume and by using the fermentation model with an extended Kalman filter. The manipulated variable, sugar feed to the fermenter, is calculated by an adaptive algorithm. Simulation results compare the performance of self-tuning control with that obtained using digital Proportional plus Integral control.     

The demography of limb dominance, body-mass index, and metatarsus adductus deformity

To test the null hypothesis that limb dominance (laterality) and side of complaint are not associated in a diverse population, nearly 400 patients (40% male, 60% female) of varying age and body size from three South Florida podiatric medical teaching facilities were surveyed in 1995-1996. Radiographs of feet were available for 15% of the patients, and the metatarsus adductus angle was measured on each x-ray. The typical patient was a women (median age, 49 years) of average body weight and average body-mass index. No statistical association was found between laterality and side of complaint in the broader sample, although a significant association did appear in the subsample of patients with bilateral x-rays. The prevalence of metatarsus adductus deformity (metatarsus adductus angle > 15 degrees) among patients with x-rays was 62%. No sex-specific, age-specific, or body size-specific associations were found between handedness and metatarsus adductus deformity.     

Crystallinity in jute fiber as revealed by multipeak resolution

A method of multipeak resolution and computation of background scatter in x-ray diffraction from fiber has been applied to jute fibers. While crystallinity as determined by this method in raw and delignified jute fibers remains unchanged, perfection of the crystalline regions improves on delignification.