Electrochemical assay of sorbitol dehydrogenase at PEDOT modified electrodes – a new milk biomarker for confirmation of pregnancy in dairy cattle

A robust electrochemical assay for sorbitol dehydrogenase (SORDH) activity in milk was developed using voltammetry and chronocoulometry at bare and polymer modified transducers. The motivation for the work was to evaluate the potential of SORDH as an early biomarker of bovine pregnancy using milk as sample matrix. SORDH is an enzyme involved in carbohydrate metabolism converting sorbitol, the sugar alcohol form of glucose, into fructose, with NAD+ as a cofactor being simultaneously reduced to NADH. The assay was optimised via direct NADH oxidation on glassy carbon and screen printed carbon electrodes followed by electropolymerisation of 3,4-ethylenedioxythiophene (EDOT) monomer to form an NADH responsive PEDOT surface which operated well in undiluted milk samples. Assay conditions such as incubation time and temperature were optimised resulting in a 3 min assay at 37 °C in the presence of 10 mM NAD+ and 20 mM sorbitol co-substrates, enabling NADH electro oxidation (linear range 0.25–5 mM, sensitivity 9.17 μC cm−2 mM−1 in undiluted milk). SORDH determination followed over the range 0.31–10 U mL−1 in milk samples with sensitivity 5.45 μC cm−2 U−1 mL with LOD 0.0787 U mL−1. The assay was applied to milk sample testing acquired as part of an approved animal study involving control and breeding cycles of dairy cows with focus on analysis at day 19 post artificial insemination. Significant differences between control and pregnant SORDH levels in whole milk animal samples were found (average values 2.57 and 4.07 ng mL−1 respectively), as verified using a commercial SORDH ELISA optical assay. Finally, progesterone monitoring over days 16–21 of the oestrous cycle employed an optical ELISA assay and confirmed maintenance of progesterone levels from day 19 onwards

European university-community partnership-based research on urban sustainability and resilience

Transitioning Towards Urban Resilience and Sustainability (TURAS) project is based on the partnership between decision makers in local authorities with SMEs and academic institutions to develop and demonstrate transition strategies for urban resilience and sustainability. Out of eleven case study sites, three are presented in this brief, including: brownfield redevelopment in London, community mobilisation around underutilisation of urban sites in Dublin, and a web portal for sustainable mobility in Ljubljana

Ultra high wind energy penetration in an isolated market

Paper presented at the IEEE Power and Energy Society 2008 PES General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century, 20-24 July 2008, Pittsburgh, PA, USAThis paper addresses the market design implications of implementing ultra high (up to 42%) wind energy penetration in an isolated market. High wind penetration is becoming an increasing feature of many markets and the impact to such markets will need to be analyzed. In this paper, the Single Electricity Market (SEM) market design is analyzed in the context of increasing wind penetration and given the results of the recently published All Island Grid Study which indicated that ultra high wind capacity could be accommodated subject to certain key assumptions.Science Foundation IrelandConference websitehttp://ewh.ieee.org/cmte/PESGM08/Charles Parsons Energy Research AwardsCharles Parso