University of Hull

About: University of Hull is a education organization based out in Hull, Kingston upon Hull, United Kingdom. It is known for research contribution in the topics: Population & Liquid crystal. The organization has 9546 authors who have published 22062 publications receiving 648925 citations.

Towards paired and coupled electrode reactions for clean organic microreactor electrosyntheses

Abstract: Electrosynthesis offers a powerful tool for the formation of anion and cation radical intermediates and for driving clean synthetic reactions without the need for additional chemical reagents. Recent advances in microfluidic reactor technologies triggered an opportunity for new microflow electrolysis reactions to be developed for novel and clean electrosynthetic processes. Naturally, two electrodes, anode and cathode, are required in all electrochemical processes and combining the two electrode processes into one “paired” reaction allows waste to be minimised. By decreasing the inter-electrode gap “paired” reactions may be further “coupled” by overlapping diffusion layers. The concept of “coupling” electrode processes is new and in some cases coupled processes in micro-flow cells are possible even in the absence of intentionally added electrolyte. The charged intermediates in the inter-electrode gap act as electrolyte and processes become “self-supported”. Hardly any examples of “coupled” paired electrochemical processes are known to date and both “paired” and “coupled” processes are reviewed here. Coupled electrode processes remain a challenge. In future “pairing” and “coupling” electrode processes into more complex reaction sequences will be the key to novel and clean flow-through microreactor processes and to novel chemistry.

Channel adjustments and alteration of sediment fluxes in gravel-bed rivers of north-eastern italy: potentials and limitations for channel recovery

Abstract: The aim of this paper is to explore possibilities and limitations of restoring physical processes in five gravel-bed rivers (Brenta, Piave, Cellina, Tagliamento and Torre Rivers) in north-eastern Italy. The selected rivers were analysed through a range of techniques, specifically analysis of historical maps and aerial photographs with geographical information systems (GIS), comparison of topographic surveys and geomorphological surveys. After illustrating channel adjustments and sediment fluxes, we discuss how the understanding of physical processes can be used for channel restoration. The studied river channels have undergone notable adjustments in the last 100 years, specifically narrowing by up to 76%, incision by up to 8.5m, and changes in channel configuration. Alteration of sediment fluxes, mainly due to in-channel mining, has been the main factor driving such channel adjustments. Evolutionary trends show that channel recovery is on-going in several of the selected reaches, since widening and aggradation have occurred over the last 15‐20 years. This channel recovery has been possible because sediment mining has significantly decreased or ceased along the study reaches. However, several constraints still exist on sediment fluxes (e.g. dams). Four categories of river channel were defined, taking into account the recent evolution of the studied channels (from ‘A’, high channel recovery, to ‘D’, no channel recovery). The impact of different sediment management strategies on channel dynamics overthenext40‐50yearswasthenanalysed.Withoutanyintervention,channel recoverywouldonlybepossibleinthosereaches that have a relatively high degree of connectivity with upstream sediment sources or tributaries, while further incision and narrowing would be expected in those reaches where connectivity is low. A more substantial channel recovery could be obtained through interventions at reach (e.g. removal of bank protection) and basin (e.g. sediment transfer downstream of dams) scales. Notwithstanding such actions, it is likely that channels will not recover in the nextfew decades to the morphology they exhibited in the first half of the 20th century, when bed-load yield and connectivity were higher. Copyright # 2009 John Wiley & Sons, Ltd.

The Diabetes Health Profile (DHP): a new instrument for assessing the psychosocial profile of insulin requiring patients--development and psychometric evaluation.

Abstract: The aim of the studies was to evaluate the psychometric properties and construct validity of the Diabetes Health Profile (DHP-1). Content for the DHP-1 was derived following in-depth interviews with 25 insulin dependent and insulin requiring patients, a review of the literature and discussions with health care professionals. Initial analysis of the factor structure of the DHP-1 was carried out on the responses of 239 insulin dependent and insulin requiring patients, with a mean age of 40.85 years (SD = 13.0), resulting in a 43 item three factor solution. The 43 item version of the DHP-1 was completed by 2,239 insulin dependent/requiring patients (mean age = 39.8, SD = 10) years. Fifty-one per cent were men. A forced three factor Principal Factoring Analysis with varimax rotation was carried out. Eleven items were excluded with item factor cross loadings > 0.30 or item factor loadings < 0.30. PAF analysis of the 32 items resulted in a three factor solution accounting for 33% of the total explained variance. The three factors were interpreted as Psychological Distress, Barriers to Activity and Disinhibited Eating. Factor congruence between subsamples were: Psychological distress (0.93), Barriers to Activity (0.93) and Disinhibited Eating (0.99). Coefficients of congruence between men and women were 0.94, 0.92 and 0.99 for Psychological Distress, Barriers to Activity and Disinhibited Eating respectively. Internal consistency of the three factors (Cronbach's alpha) were: Psychological Distress (0.86), Barriers to Activity (0.82), and Disinhibited Eating (0.77). Construct-convergent validity was investigated on a sample of 233 insulin dependent and insulin requiring patients (mean age = 51.46 years). Psychological Distress and Barriers to Activity subscales correlated with the Hospital Depression and Anxiety Scale = 0.50 to 0.62, p < 0.01) and subscales of the SF-36 (range: r = -0.17 to -0.62, p < 0.01). These findings lend support to the construct validity and reliability of the DHP-1 and that it is suitable for further development.

Fabrication techniques and materials commonly used for the production of microreactors and micro total analytical systems

Abstract: Over the last decade, microfabrication techniques have been reported for the production of devices in which fluidic manipulation and component separations of chemical and biological materials can be carried out. The term micro total analytical system (μTAS) is an accepted concept. However, it is perhaps the potential application of microfabricated devices in the wider context that has given added momentum to their development. In this review, the focus will be on the materials and fabrication methods frequently encountered for the production of such devices. Fluidic manipulation is achieved with either hydrostatic displacement pumps such as the syringe pump or electro-osmotic flow, which brings the added advantage of electrophoretic separations.