Further studies aimed at examining the activity of different Cu(II)-ligand complexes to serve as electron-transfer mediators to prepare novel antimicrobial/thromboresistant nitric oxide (NO)-releasing intravenous catheters are reported. In these devices, the NO release can be modulated by applying different potentials or currents to reduce the Cu(II)-complexes to Cu(I) species which then reduce nitrite ions into NO within a lumen of the catheter. Four different ligands are compared with respect to NO generation efficiency and stability over time using both single- and dual-lumen silicone rubber catheters: N-propanoate- N, N-bis(2-pyridylethyl)amine (BEPA-Pr), N-propanoate- N, N-bis(2-pyridylmethyl)amine (BMPA-Pr), 1,4,7-trimethyl-1,4,7-triazacyclononane (MeTACN), and tris(2-pyridylmethyl)amine (TPMA). Of these, the Cu(II)BEPA-Pr and Cu(II)MeTACN complexes provide biomedically useful NO fluxes from the surface of the catheters, >2 × 10 mol·min·cm, under conditions mimicking the bloodstream environment. Cu(II)MeTACN exhibits the best stability over time with a steady and continuous NO release observed for 8 d under a nitrogen atmosphere. Antimicrobial experiments conducted over 5 d with NO-releasing catheters turned "on" electrochemically for only 3 or 6 h each day revealed >2 logarithmic units in reduction of bacterial biofilm attached to the catheter surfaces. The use of optimal Cu(II)-ligand complexes within a lumen reservoir along with high levels of nitrite ions can potentially provide an effective method of preventing/decreasing the rate of infections caused by intravascular catheters.
This article introduces a mathematical model for photogrammetric processing of linear array stereo images acquired by high-resolution satellite imaging systems such as IKONOS. The experimental result of the generation of simulated IKONOS stereo images based on photogrammetric principles, IKONOS imaging geometry and a set of georeferenced aerial images is presented. An accuracy analysis of ground points derived from the simulated IKONOS stereo images is performed. The impact of the number of GCPs (ground control points), distribution of GCPs, and image measurement errors on the ground point accuracy is investigated. It is concluded that an accuracy of ground coordinates from 2 m to 3 m is attainable with GCPs, and 5 m to 12 m without GCPs. Two data sets of HRSC (high resolution stereo camera) and MOMS (modular opto-electronic multispectral stereo-scanner)-2P are also utilized to test the model and system. The presented data processing method is a key to the generation of mapping products such as digital terrain models (DEM) and digitial shorelines from high-resolution satellite images.
IntroductionThe new generation of commercial one-metre resolution satellite imaging systems, represented by the IKONOS system that was successfully launched in September 1999, will open a new era for digital mapping (Fritz 1996, Li 1998. Several commercial high-resolution satellite imaging systems were scheduled for launch in 2001 and thereafter, for example, EarlyBird (3 m) and QuickBird (1 m/4 m) from EarthWatch Inc., OrbView-1 (1 m/2 m) of Orbital Science Corporation, and IKONOS (1 m) from SpaceImaging EOSAT.Early theoretical analysis indicated that the new generation of high-resolution satellite images will provide an accuracy of 12 m (planimetric) and 8 m (vertical) without ground control points (GCPs). With the addition of GCPs, the systems can achieve an accuracy of 2 m (planimetric) and 3 m (vertical). This level of accuracy is considered su Y cient to support the generation of most national mapping products (Li
Nitric oxide (NO) levels in exhaled breath are a non-invasive marker that can be used to diagnose various respiratory diseases and monitor a patient’s response to given therapies. A portable and inexpensive device that can enable selective NO concentration measurements in exhaled breath samples is needed. Herein, the performance of an amperometric Pt-Nafion-based gas phase sensor for detection of NO in exhaled human nasal breath is examined. Enhanced selectivity over carbon monoxide and ammonia is achieved via an in-line zinc oxide-based filter. Exhaled nasal NO levels measured in 21 human samples with the sensor are shown to correlate well with those obtained using a chemiluminescence reference method (R2 = 0.9836).
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