83 research outputs found
Photolithographic patterning of conducting polyaniline films via flash welding
In this work, two significant advances in photolithographic patterning of polyaniline (PANI) films are reported. Firstly, flash welding was enhanced through the use of polymeric substrates, enabling complete penetration of the welding of PANI films with thicknesses ranging from 5 to over 14 mu m, significantly thicker than reported previously. Masking of parts of the PANI films during flash welding enabled the formation of adjacent conducting and insulating regions as the welding changes the electrical properties of the film. Raman spectroscopy was used to determine the sharpness of these edges, and indicated that the interface between the flash welded and masked regions of the PANI films was typically less than 15 mu m wide. Secondly, using longpass filters, light with a wavelength less than 570 nm was found not to contribute to the welding process. This was confirmed by the use of a 635 nm laser diode for welding the PANI films. This novel approach enabled patterning of PANI films using a direct writing technique with a narrow wavelength light source
Initial microbial spectrum in severe secondary peritonitis and relevance for treatment
This study aims to determine whether abdominal microbial profiles in early severe secondary peritonitis are associated with ongoing infection or death. The study is performed within a randomized study comparing two surgical treatment strategies in patients with severe secondary peritonitis (n = 229). The microbial profiles of cultures retrieved from initial emergency laparotomy were tested with logistic regression analysis for association with ‘ongoing infection needing relaparotomy’ and in-hospital death. No microbial profile or the presence of yeast or Pseudomonas spp. was related to the risk of ongoing infection needing relaparotomy. Resistance to empiric therapy for gram positive cocci and coliforms was moderately associated with ongoing abdominal infection (OR 3.43 95%CI 0.95–12.38 and OR 7.61, 95%CI 0.75–76.94). Presence of only gram positive cocci, predominantly Enterococcus spp, was borderline independently associated with in-hospital death (OR 3.69, 95%CI 0.99–13.80). In secondary peritonitis microbial profiles do not predict ongoing abdominal infection after initial emergency laparotomy. However, the moderate association of ongoing infection with resistance to the empiric therapy compels to more attention for resistance when selecting empiric antibiotic coverage
Improved cost models for optimizing CO2 pipeline configuration for point-to-point pipelines and simple networks
In this study, a new cost model is developed for CO2 pipeline transport, which starts with the physical properties of CO2 transport and includes different kinds of steel grades and up-to-date material and construction costs. This pipeline cost model is used for a new developed tool to determine the configuration leading to the lowest levelized costs for CO2 transport, for point-to-point pipelines as well as for simple networks on different types of terrain and for different time frames. The model optimizes inlet pressure, diameter, steel grade and number of pumping stations. Results show that gaseous CO2 transport can give lower levelized costs than liquid CO2 transport for point-to-point pipelines and for simple networks, if the CO2 is stored in a reservoir with a low required injection pressure, like depleted natural gas fields. However, for storage fields with a required injection pressure of 8 MPa or higher (like aquifers), CO2 can be better transported in a liquid form. For onshore pipelines transporting liquid CO2, the optimal inlet pressure is 9-13 MPa and pumping stations are installed roughly every 50-100 km. For offshore pipelines, pumping stations are not an option and the inlet pressure is determined by the length of the pipeline. The maximum inlet pressure is about 25 MPa and for even longer pipelines, a larger diameter is selected. The levelized costs (excluding initial compression) for transporting 100 kg/s (about 3 Mt/y) over 100 km are between 1.8 and 33 (sic)/t for liquid and 4.0-6.4 (sic)/t for gaseous CO2 transport. For larger mass flows the costs are decreasing, for instance transporting 200 kg/s (about 6 Mt/y) over 100 km are 1.2-1.8 (sic)/t for liquid and 3.0-3.8 (sic)/t for gaseous CO2 transport. Furthermore, results show that higher steel grades lead to lower investment costs for onshore pipelines transporting liquid CO2. Using X120 in the long term reduces the pipeline costs up to 17%. For gaseous CO2 transport, lower steel grades (like X42 and X52) are the best option. Also offshore pipelines do not benefit from the development of higher steel grades over time because the thickness should be at least 2.5% of the outer diameter. The results indicate that oversizing the pipeline, to transport CO2 from an additional source that is coming available later, is not always cost-attractive. This strongly depends on the time span of which further CO2 sources are available and on the mass flows. Oversizing appears earlier cost-attractive compared to two point-to-point pipelines if the source with the largest mass flow becomes available first. (C) 2014 Elsevier Ltd. All rights reserved
Fixed Channel Road link
A fixed road link between Dover and Calais can be realized by a tunnel, a bridge or The tunnel can be bored which are submerged into a combination of bridge and tunnel or constructed of concrete elements place.Offshore technologyHydraulic EngineeringCivil Engineering and Geoscience
Test-retest reliability of heart rate variability and respiration rate at rest and during light physical activity in normal subjects
BACKGROUND: A variable that remains stable over repeated measurements (in stable conditions) is ideal for tracking modifications of the clinical state. The aim of the present study is to examine test-retest reliability of time-domain heart rate variability and respiration rate measurements using a portable device on normal subjects during rest and light physical activity. METHODS: Twenty-six normal subjects [18 females and 8 males aged 28 +/- 6 years and 34 +/- 12 years (mean +/- SD), respectively] underwent two measurements for time-domain heart rate variability (SDNN and RMSSD) and respiration rate, with 7 days in between. Measurements took place under three conditions: lying down in a laboratory, cycling in a laboratory and sleeping in an ambulatory surrounding. Reliability was assessed statistically by calculating intra-class correlation coefficients (ICC). RESULTS: Reliability was found to be good to excellent for both time-domain heart rate variability (SDNN: ICC values between 0.74 and 0.85, RMSSD: ICC values between 0.75 and 0.98) and for respiration rate (ICC values between 0.77 and 0.96). CONCLUSIONS: Both time-domain heart rate variability and respiration rate can be reliably assessed. However, we advise reliability research in a clinical setting before using the device for tracking modifications in a clinical stat
Ion transport in broad bean leaf mesophyll under saline conditions
Main conclusion Salt stress reduces the ability of mesophyll tissue to respond to light. Potassium outward rectifying channels are responsible for 84 % of Na⁺ induced potassium efflux from mesophyll cells. Modulation in ion transport of broad bean (Vicia faba L.) mesophyll to light under increased apoplastic salinity stress was investigated using vibrating ion-selective microelectrodes (the MIFE technique). Increased apoplastic Na⁺ significantly affected mesophyll cells ability to respond to light by modulating ion transport across their membranes. Elevated apoplastic Na⁺ also induced a significant K⁺ efflux from mesophyll tissue. This efflux was mediated predominately by potassium outward rectifying channels (84 %) and the remainder of the efflux was through nonselective cation channels. NaCl treatment resulted in a reduction in photosystem II efficiency in a dose- and time-dependent manner. In particular, reductions in Fv‘/Fm‘ were linked to K⁺ homeostasis in the mesophyll tissue. Increased apoplastic Na⁺ concentrations induced vanadate-sensitive net H⁺ efflux, presumably mediated by the plasma membrane H⁺-ATPase. It is concluded that the observed pump’s activation is essential for the maintenance of membrane potential and ion homeostasis in the cytoplasm of mesophyll under salt stress.William J. Percey, Lana Shabala, Michael C. Breadmore, Rosanne M. Guijt, Jayakumar Bose, Sergey Shabal
Improved cost models for optimizing CO2 pipeline configuration for point-to-point pipelines and simple networks
In this study, a new cost model is developed for CO2 pipeline transport, which starts with the physical properties of CO2 transport and includes different kinds of steel grades and up-to-date material and construction costs. This pipeline cost model is used for a new developed tool to determine the configuration leading to the lowest levelized costs for CO2 transport, for point-to-point pipelines as well as for simple networks on different types of terrain and for different time frames. The model optimizes inlet pressure, diameter, steel grade and number of pumping stations. Results show that gaseous CO2 transport can give lower levelized costs than liquid CO2 transport for point-to-point pipelines and for simple networks, if the CO2 is stored in a reservoir with a low required injection pressure, like depleted natural gas fields. However, for storage fields with a required injection pressure of 8 MPa or higher (like aquifers), CO2 can be better transported in a liquid form. For onshore pipelines transporting liquid CO2, the optimal inlet pressure is 9-13 MPa and pumping stations are installed roughly every 50-100 km. For offshore pipelines, pumping stations are not an option and the inlet pressure is determined by the length of the pipeline. The maximum inlet pressure is about 25 MPa and for even longer pipelines, a larger diameter is selected. The levelized costs (excluding initial compression) for transporting 100 kg/s (about 3 Mt/y) over 100 km are between 1.8 and 33 (sic)/t for liquid and 4.0-6.4 (sic)/t for gaseous CO2 transport. For larger mass flows the costs are decreasing, for instance transporting 200 kg/s (about 6 Mt/y) over 100 km are 1.2-1.8 (sic)/t for liquid and 3.0-3.8 (sic)/t for gaseous CO2 transport. Furthermore, results show that higher steel grades lead to lower investment costs for onshore pipelines transporting liquid CO2. Using X120 in the long term reduces the pipeline costs up to 17%. For gaseous CO2 transport, lower steel grades (like X42 and X52) are the best option. Also offshore pipelines do not benefit from the development of higher steel grades over time because the thickness should be at least 2.5% of the outer diameter. The results indicate that oversizing the pipeline, to transport CO2 from an additional source that is coming available later, is not always cost-attractive. This strongly depends on the time span of which further CO2 sources are available and on the mass flows. Oversizing appears earlier cost-attractive compared to two point-to-point pipelines if the source with the largest mass flow becomes available first. (C) 2014 Elsevier Ltd. All rights reserved
Sheathless Separation of CyanobacterialAnabaenaby Shape Using Viscoelastic Microfluidics
Cyanobacteria have a wide range of impact on natural ecosystems, and have been recognized as potentially rich sources of pharmacological and structurally interesting secondary metabolites. To better understand the basic molecular processes and mechanisms that influence and regulate the growth (like length) of cyanobacteria, or connections between environment, genotype, and phenotype, it would be essential to separate shape-synchronized cyanobacterial cell populations with relatively uniform length and size. This work proposes a novel and efficient method to separate cyanobacterial Anabaena by shape (rod aspect ratio) using viscoelastic microfluidics in a straight channel with expansion-contraction cavity arrays (ECCA channel). The biocompatible viscoelastic solutions with dissolved polymer would induce a combined effect of inertial lift force, elastic force, and secondary drag force for Anabaena flowing in it. Therefore, Anabaena with different lengths reach different lateral equilibrium positions and flow out from different outlets. Factors including flow rate, fluid viscoelasticity, channel structure, and length on the shape-based cell separation were studied systematically. This work, for the first time, demonstrates continuous and sheathless shape-based separation of cyanobacteria using viscoelastic microfluidics. Moreover, its ability to manipulate objects with different morphologies and with a size of \u3e100 μm will extend the capability of microfluidics to a completely new field that has never been reached and would be attractive across a range of new applications
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