Application of Room Temperature Ionic Liquids to the Development of Electrochemical Lipase Biosensing Systems for Water-Insoluble Analytes

Biosensors have been prepared by modification of glassy carbon electrodes with functionalised multiwalled carbon nanotubes (MWCNT) dispersed in the room temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethane)sulfonimide (BmimNTF2) and with lipase cross-linked with glutaraldehyde. The biosensor was applied to the determination of olive oil triglycerides by cyclic voltammetry. A phosphate buffer (pH 7.0) / BmimNO3 mixture is a better electrolyte than aqueous buffer alone. The response signal in the buffer-BmimNO3 mixture was found to increase with the number of cycles until a constant current was achieved. The calibration curve obtained exhibited a sigmoid-shape and a fourparameter model was used to fit the data which gave a limit of detection of 0.11 μg mL−1. Close inspection of such calibration curves showed two distinct linear regions indicating changes in the mechanism of the electrochemical response. Overall, the oxidative analytical response was found to be due to phenolic compounds present in the olive oil, released in the presence of lipase, rather than due to triglycerides per se. It was also found that there were no interferences from either cholesterol or glycerol. A possible mechanism of olive oil determination at a MWCNT-BmimNTF2/Lip biosensor is proposed

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Polarimetric Change Detection for Wetlands

An exciting development in wetland mapping and monitoring is the use of SAR polarimetry which uses both magnitude and phase of the backscattered radar signal for information extraction. This approach allows for the accurate delineation of flooded vegetation due to the double bounce scattering mechanism which the phase helps to identify unambiguously. Repeat pass polarimetric data is then used to monitor the temporal change in flooded vegetation. This information is useful for a variety of applications in wetland mapping and monitoring. This paper will present a novel Curvelet-based technique for the enhancement of polarimetric decomposition channels as well as temporal differences in these channels. Starting with the Freeman-Durden and the Cloude-Pottier polarimetric decomposition of Radarsat-2 data the Curvelet image enhancement and the Curvelet change detection are applied. The results are very promising although a validation by comparison with ground truth data still has to be done

Being Female: a handicap for researchers in the competion for NCCR.

The Swiss National Science Foundation made a call for National Centers fo Competence in Research (NCCR) for the first time in 1999 and 2004. Together, these announcements concerned all disciplines and led to 126 preproposals, which were put forward by 2134 men and women researchers. It can be assumed that this operation mobilised Swiss researchers who regarded themselves as particularly well qualified to conduct high-level research in their field. The article uses network analysis and regression analysis methods to examine to what extend women had a lower success rate than men in the two selection rounds because of their sex. On the whole, the findings attest the gender neutrality of the National Science Foundation's selection procedures. However, they also confirm the well-known fact that women scientists are less represented in the higher echelons of academia and concentrated in the social sciences and humanities, as well as showing that this concentration reduces women's chances of success in scientific competition. The article shows that unequal gender-specific success rates prior to the NCCR funding contest play a fairly significant role

Evaluation of RADARSAT-2 Acquisition Modes for Wetland Monitoring Applications

Interferometric synthetic aperture radar (InSAR) techniques can monitor water-level changes in wetlands with suitable coherence. RADARSAT-2 has many beam modes with varying system parameters to satisfy a wide range of applications. During data acquisition the SAR signals are digitized using eight-bit analog-to-digital converters followed by block adaptive quantization (BAQ) coding. Most RADARSAT-2 beam modes use three-bit BAQ but some modes use two-bit BAQ to accommodate larger data sets, including the wide multilook fine and wide ultrafine modes. These modes are attractive for surface monitoring applications due to good resolution over a wide swath. The two-bit BAQ can have signal saturation due to the smaller dynamic range and an increased phase noise. The Everglades National Park (ENP) has been used for numerous InSAR investigations of water level monitoring. This study describes the results of an evaluation of RADARSAT-2 products from different modes for the monitoring of water-level changes and flooded vegetation in ENP. The objective was to evaluate products from a variety of beam modes for wetland monitoring applications and subsequent unwrapping of the interferograms for water level estimation. The results show that wide-swath high-resolution modes are suitable for InSAR applications due to adequate coherence and high backscatterintensity

Temporal Filters for Mapping Phragmites with C-HH SAR Data

We compared traditional spatial filters and multi-temporal filters to remove speckle from synthetic aperture radar (SAR) data for mapping Phragmites australis. SAR constellations, with more rapid revisit capability, allow one to generate stacks of SAR data and to use multi-temporal filters for speckle reduction. GAMMA software offers multi-temporal filters for SAR processing, two of which we compared to the traditional Enhanced Lee and the Lee filters. We evaluated the filters using three criteria: (1) visual inspection, (2) signal level ratio, and (3) the equivalent number of looks (ENL). The results of this study show that multi-temporal filters were able to reduce speckle from areas of surface water and land, as well as to improve the detection of Phragmites patches due to preserving the resolution and texture which helped in the detection of the patch boundaries. The signal level ratio was approximately 1.0 with the GAMMA Multi-temporal filter and approximately 0.9 with the other filters. The enhanced Lee and the two multi-temporal filters produced an equal ENL of about 6. However, due to small patch sizes and backscatter similarity with cattails and other cover types Phragmites patches were difficult to separate from other types of flooded vegetation with C-HH intensity only

SAR polarimetric change detection for flooded vegetation

Due to spatial and temporal variability an effective monitoring system for water resources must consider the use of remote sensing to provide information. Synthetic Aperture Radar (SAR) is useful due to timely data acquisition and sensitivity to surface water and flooded vegetation. The ability to map flooded vegetation is attributed to the double bounce scattering mechanism, often dominant for this target. Dong Ting Lake in China is an ideal site for evaluating SAR data for this application due to annual flooding caused by mountain snow melt causing extensive changes in flooded vegetation. A curvelet-based approach for change detection in SAR imagery works well as it highlights the change and suppresses the speckle noise. This paper addresses the extension of this change detection technique to polarimetric SAR data for monitoring surface water and flooded vegetation. RADARSAT-2 images of Dong Ting Lake demonstrate this curvelet-based change detection technique applied to wetlands although it is applicable to other land covers and for post disaster impact assessment. These tools are important to Digital Earth for map updating and revision

Multi-sensor wetland mapping over the Peace Athabasca Delta

The joint use of diverse sensors is of major interest in the remote sensing community. With view to the repeata-bility of acquisitions, todays satellite sensor systems provide a temporal resolution of about one month in the Shannon sense. Thus, the joint use of different sensor systems is unavoidable for monitoring purposes. This contribution designs a novel similarity transformation that extracts class similarities based on local distributions from any available image independent of sensor (TerraSAR-X, RADARSAT-2, Sentinel-1) or polarimetric mode (Quad, Dual-Co, Dual-Cross, Single). The resulting class probability development characterizes the temporal change of the Peace Athabasca Delta in Northern Canada

Effects of Disturbance and Climate Change on Ecosystem Performance in the Yukon River Basin Boreal Forest

A warming climate influences boreal forest productivity, dynamics, and disturbance regimes. We used ecosystem models and 250 m satellite Normalized Difference Vegetation Index (NDVI) data averaged over the growing season (GSN) to model current, and estimate future, ecosystem performance. We modeled Expected Ecosystem Performance (EEP), or anticipated productivity, in undisturbed stands over the 2000–2008 period from a variety of abiotic data sources, using a rule-based piecewise regression tree. The EEP model was applied to a future climate ensemble A1B projection to quantify expected changes to mature boreal forest performance. Ecosystem Performance Anomalies (EPA), were identified as the residuals of the EEP and GSN relationship and represent performance departures from expected performance conditions. These performance data were used to monitor successional events following fire. Results suggested that maximum EPA occurs 30–40 years following fire, and deciduous stands generally have higher EPA than coniferous stands. Mean undisturbed EEP is projected to increase 5.6% by 2040 and 8.7% by 2070, suggesting an increased deciduous component in boreal forests. Our results contribute to the understanding of boreal forest successional dynamics and its response to climate change. This information enables informed decisions to prepare for, and adapt to, climate change in the Yukon River Basin forest

The Synergistic Use of RADARSAT-2 Ascending and Descending Images to Improve Surface Water Detection Accuracy in Alberta, Canada

Large, e.g., provincial or national, scale near-real-time surface water monitoring is an ambitious task, which can be accomplished by using Synthetic Aperture Radar (SAR) satellite data. SAR has demonstrated the ability to distinguish water and land, but there are many common errors of commission and omission that arise due to the side-looking nature of SAR and due to some landcover types with similar backscatter like roads and pasture. A method is proposed to fix/mitigate these errors through the use of combined ascending/descending RADARSAT-2 image pairs and ancillary data. The results of a corrected water/land binary image were, on average, 99.4% accurate for the Boreal Forest Region (Utikuma) of Alberta, Canada, while for the Rocky Mountain Region (Westcastle) also in Alberta, the results proved to be 99.9% accurate when distinguishing water from land. These accuracies were achieved through the reduction of the water false positive rate and a slight reduction in the water true positive rate. These high accuracy values can be partially attributed to the relative low ratios of water to land in the study regions. We hope that these methods can be used and improved in order to move towards large scale dynamic surface water and wetland mapping