Michael Sharp - Academia.edu (original) (raw)

Papers by Michael Sharp

Fisheries Newsletter, Sep 1, 2011

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1986

... OF STABILIZED, PROTONATED POLY-4-VINYLPYRIDINE FILMS CONTAINING ELECTROACTIVE ANIONS ON GLASS... more ... OF STABILIZED, PROTONATED POLY-4-VINYLPYRIDINE FILMS CONTAINING ELECTROACTIVE ANIONS ON GLASSY CARBON ELECTRODE SURFACES BRITTA LINDHOLM and ... 95 5) films on basal-plane graphite electrodes has been mea-sured earlier by Anson et al ...

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1989

According to a kinetic model, the maximum currents, il.,,=. that can be obtained from the mediate... more According to a kinetic model, the maximum currents, il.,,=. that can be obtained from the mediated oxidation of ferrocyanide at glassy-carbon electrodes covered with Nafion@ */Os(bipy):+ films are determined jointly by film conductivity and by a saturation in the rate of the surface reaction. Values of il,max, predicted on the basis of chronocoulometrically measured charge-propagation currents, i,, agreed with those actually recorded by rotating-disc techniques. These observations confirmed the validity of the model and further indicated that i, for these systems was the same for both transient and steady-state conditions, in contradiction with earlier published results. Significant electron hopping between neighbouring redox sites within these coatings was revealed by the dependence of the apparent charge-transport diffusion coefficient, D,(app), on mediator concentration, c~. Attempts were made to explain these results in terms of parallel conduction pathways, variable electron-hopping distances, and migrational effects. l Registered trademark, perfluorosulphonic acid membrane, DuPont.

Fish processing is an important activity in the Pacific, but it generates a lot of by-products th... more Fish processing is an important activity in the Pacific, but it generates a lot of by-products that are not used in a way that maximises their economic potential. There is opportunity to turn fish processing by-products into food, fish meal, fertiliser, pharmaceutical and other marketable products. The problem is that fish processors operate to extract the most value from their primary products, with little attention being dedicated to extracting value from by-products. This results in missed economic return from this secondary resource due to underinvestment in technologies that add value to by-products. In addition to this missed opportunity, disposal of by-products often has a direct financial and environmental cost. In some Pacific sland countries and territories, fish processors are already extracting value and creating employment by processing by-products, but more value can be extracted. A first step in assessing the potential to add more value to fish processing by-products ...

Journal of Vascular Surgery, 2013

Aneurysms of the profunda femoris artery (PFA) are uncommon. We present a patient with a PFA aneu... more Aneurysms of the profunda femoris artery (PFA) are uncommon. We present a patient with a PFA aneurysm resulting in a deep venous thrombosis (DVT) of the femoral vein due to extrinsic compression. A 63-year-old man was referred from the community with a 2-week history of left leg swelling. He was a former smoker, with no other medical comorbidity, and no history of trauma, needle use in the left groin, previous DVT, or significant family history. On examination, his limb was diffusely swollen, and there was isolated, firm, upper left thigh swelling with a transmitted pulse. All peripheral pulses were felt, and there was no palpable abdominal aortic aneurysm. A duplex scan confirmed a superficial femoral DVT and a 5-cm thrombosed PFA aneurysm. A computed tomography angiogram revealed a 5.5-cm aneurysm with a calcified wall arising from a proximal medial branch of the PFA artery (A and B) causing marked venous compression. No other aneurysms were found in the arterial tree. The patient received anticoagulation with low-molecular-weight heparin. He was offered surgery for the profunda aneurysm that was causing extrinsic compression on the femoral vein, which he declined, and thereafter was commenced on warfarin. A repeat duplex scan in 6 weeks showed the initial findings and the long saphenous vein draining into the common femoral vein. DISCUSSION True aneurysms of the PFA are seldom encountered in surgical practice. The reported incidence ranges from 1% to 6% of femoral artery aneurysms. 1 The principle etiology of these aneurysms is trauma, whether extrinsic, orthopedic, or iatrogenic. 2 Primary aneurysms, such as in this patient, are much rarer. Presentations range from asymptomatic to rupture. A thorough literature review revealed only one previous case of a PFA aneurysm leading to venous thrombosis. 3

Journal of Geotechnical and Geoenvironmental Engineering, 2008

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurr... more Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.

Journal of Electroanalytical Chemistry, 1992

... The influence of the binding type of the electroactive complex Henrik Larsson, Britta Lindhol... more ... The influence of the binding type of the electroactive complex Henrik Larsson, Britta Lindholm and Michael Sharp Department of Analytical ... An early study of pentacyanoferroate(II) 265 coordinated to protonated PVP films was reported by Anson and coworkers [5]. They obtained ...

Journal of Electroanalytical Chemistry, 1993

Impedance techniques were employed to measure charge-propagation rates in Nafion/Os (bipy) 3 3+/2... more Impedance techniques were employed to measure charge-propagation rates in Nafion/Os (bipy) 3 3+/2+ and Nafion/C 5 H 5 FeC 5 H 4 CH 2 N(CH 3 ) 3 2+/+ films on glassy carbon electrode surfaces. Redox conductivities and apparent charge-transport diffusion coefficients were ...

Journal of Electroanalytical Chemistry, 1994

Abstract A non-isothermal cell was employed to determine the reaction entropies Δ S ° rc of sever... more Abstract A non-isothermal cell was employed to determine the reaction entropies Δ S ° rc of several electroactive transition metal complexes in aqueous solution and in Nafion® and poly(styrenesulphonate) coatings deposited on glassy carbon electrode surfaces. In contrast with earlier results, the Δ S ° rc values recorded indicated that the ionic environments are significantly different in these media and that electron exchange rates are lower in the polymers than in aqueous solution. Differential Gibbs energies, enthalpies and entropies corresponding to the distribution of the oxidized and reduced components of each redox couple between the polymer phases and the solution were also evaluated.

Journal of Electroanalytical Chemistry, 1998

Impedance spectra were recorded for glassy carbon electrodes coated with poly(styrenesulphonate) ... more Impedance spectra were recorded for glassy carbon electrodes coated with poly(styrenesulphonate) and Nafion ® films containing Os(2,2%-bipyridine) 3 3 +/2 + as a function of the concentration of incorporated redox sites and applied potential. Experimental data were interpreted in terms of equivalent circuits based on finite transmission lines. Comparisons of the redox capacitances derived from cyclic voltammetry and from impedance spectroscopy showed that only a fraction of the total number of redox sites present in Nafion ® coatings was active during impedance measurements. The concentration dependence of the apparent diffusion coefficient for electron propagation through Nafion ® films suggested the presence of charge percolation.

International Journal of Human-Computer Studies, 2007

In this paper we describe the development and testing of a tool for self-assessment of affect whi... more In this paper we describe the development and testing of a tool for self-assessment of affect while interacting with computer systems, meant to be used in many cultures. We discuss our research approach within the context of existing cultural, affective and HCI theory, and describe testing of its effectiveness in the US and Sweden.

Electrochimica Acta, 1995

The apparent discrepancy between pseudocapacitances measured with different techniques which is o... more The apparent discrepancy between pseudocapacitances measured with different techniques which is observed for thin poly(4-vinylpyridine) coatings containing IrCIi-'3-on gold electrodes is discussed. The phenomenon is explained by the establishment of slow relaxation processes in the charge transport mechanism at high concentrations of redox sites.

Electrochimica Acta, 1993

A rapid method for the preparation of thin fdms of poly-(styrenesulphonate) on gla88y-MrbOn eh?ct... more A rapid method for the preparation of thin fdms of poly-(styrenesulphonate) on gla88y-MrbOn eh?ctrodes is described. The incorporation of Os(bipy):+/*+ redox sites into such coatings by ionexchange yielded modified electrodes that were sufficiently stable in aqueous media to permit studies of the Os(bipy):+-mediated oxidation8 of ferrocyanide, hexacyanoruthenate(I1) and catechol by means of rotating-disc electrode techniques. The results obtained were analysed in terms of the kinetic models established by Andrieux and SaGant.

BMC Veterinary Research, 2012

Background: A common approach to the application of epidemiological models is to determine a sing... more Background: A common approach to the application of epidemiological models is to determine a single (point estimate) parameterisation using the information available in the literature. However, in many cases there is considerable uncertainty about parameter values, reflecting both the incomplete nature of current knowledge and natural variation, for example between farms. Furthermore model outcomes may be highly sensitive to different parameter values. Paratuberculosis is an infection for which many of the key parameter values are poorly understood and highly variable, and for such infections there is a need to develop and apply statistical techniques which make maximal use of available data. Results: A technique based on Latin hypercube sampling combined with a novel reweighting method was developed which enables parameter uncertainty and variability to be incorporated into a model-based framework for estimation of prevalence. The method was evaluated by applying it to a simulation of paratuberculosis in dairy herds which combines a continuous time stochastic algorithm with model features such as within herd variability in disease development and shedding, which have not been previously explored in paratuberculosis models. Generated sample parameter combinations were assigned a weight, determined by quantifying the model's resultant ability to reproduce prevalence data. Once these weights are generated the model can be used to evaluate other scenarios such as control options. To illustrate the utility of this approach these reweighted model outputs were used to compare standard test and cull control strategies both individually and in combination with simple husbandry practices that aim to reduce infection rates. Conclusions: The technique developed has been shown to be applicable to a complex model incorporating realistic control options. For models where parameters are not well known or subject to significant variability, the reweighting scheme allowed estimated distributions of parameter values to be combined with additional sources of information, such as that available from prevalence distributions, resulting in outputs which implicitly handle variation and uncertainty. This methodology allows for more robust predictions from modelling approaches by allowing for parameter uncertainty and combining different sources of information, and is thus expected to be useful in application to a large number of disease systems. Background Simulation studies provide a useful insight into the dynamics of epidemiological systems and can be used to obtain a variety of predictions, such as the relative gains

Analytica Chimica Acta, 1976

Abstract The primary redox reactions for solid-state ion-selective electrodes prepared from elect... more Abstract The primary redox reactions for solid-state ion-selective electrodes prepared from electronically semiconducting salts of 7, 7, 8, 8-tetracyanoquinodimethane (tcnq) can be identified by considering the redox properties of their constituent ions or molecules. Three ...

Air Medical Journal, 1994

Air Medical Journal, 1995

Pediatric airway control, including endotracheal intubation (ETI), presents a clinical challenge ... more Pediatric airway control, including endotracheal intubation (ETI), presents a clinical challenge in the prehospital setting. Endotracheal intubation is recommended for serious head injury (Glasgow Coma Scale score a). We evaluated the frequency of ET in pediatric and adult patients with GCS Q3 in the field, subsequently transported by a hospital-based, helicopter emergency medical selvice (HHEMS). Methods: A retrospective, descriptive study of pediatric patients (<I4 years) and adult patients with GCS 28 transported by HHEMS

The Classical Review, 2000