Impact of Cold Climates on Vehicle Emissions: The Cold Start Air Toxics Pulse

This project measured cold start emissions from four vehicles in winter using fast response instrumentation to accurately measure the time variation of the cold start emission pulse. Seventeen successful tests were conducted over a temperature range of -4°C to 10°C in winter 2015 at the Washington State University campus. Vehicle cold starts are thought to be a significant source of air toxic compounds in cold winter environments due to the rapid increase in mass emission rates with decreasing temperature. We used a proton transfer reaction mass spectrometer for high time resolution measurement of the emissions the air toxic compounds benzene, formaldehyde, acetaldehyde, in addition to toluene and C2-alkylbenzenes. Measured molar emission ratios relative to toluene in the cold start pulse were compared with cold start emission profiles for E10 fueled vehicles used in the EPA MOVES2014 model. We found that the measured acetaldehyde-to-toluene emission ratio was about a factor of 8 greater than the emission ratio used in MOVES2014. Measured formaldehyde-to-toluene emission ratios were a factor of 5 greater. Our study suggests that emission of the air toxics acetaldehyde and, likely, formaldehyde is significantly underestimated in wintertime by the MOVES2014 model

Isolating contour information from arbitrary images

Aspects of natural vision (physiological and perceptual) serve as a basis for attempting the development of a general processing scheme for contour extraction. Contour information is assumed to be central to visual recognition skills. While the scheme must be regarded as highly preliminary, initial results do compare favorably with the visual perception of structure. The scheme pays special attention to the construction of a smallest scale circular difference-of-Gaussian (DOG) convolution, calibration of multiscale edge detection thresholds with the visual perception of grayscale boundaries, and contour/texture discrimination methods derived from fundamental assumptions of connectivity and the characteristics of printed text. Contour information is required to fall between a minimum connectivity limit and maximum regional spatial density limit at each scale. Results support the idea that contour information, in images possessing good image quality, is (centered at about 10 cyc/deg and 30 cyc/deg). Further, lower spatial frequency channels appear to play a major role only in contour extraction from images with serious global image defects

Iodine-123 labeled reboxetine analogues for imaging of noradrenaline transporter in brain using single photon emission computed tomography

Preliminary investigation of the radioiodinated (S,S)-reboxetine analogue, 123I-INER, in baboons showed this tracer to have promise for imaging the noradrenaline transporter (NAT) using single photon emission computed tomography (SPECT). More recently, the radioiodinated (R,S)-stereoisomer of 123I-INER, 123I-NKJ64, has been synthesized and preliminary evaluation in rats has been reported. This article reports the brain distribution and pharmacokinetic properties of 123I-NKJ64 in baboons and compares results with 123I-INER data in the same species. SPECT studies were conducted in two ovariectomized adult female baboons using two different protocols: (1) bolus of 123I-INER or 123I-NKJ64; and (2) bolus plus constant infusion of 123I-NKJ64 with reboxetine (2.0 mg/kg) administration at equilibrium. Following bolus injection, both radiotracers rapidly and avidly entered the baboon brain. The regional brain accumulation of 123I-NKJ64 did not match the known distribution of NAT in baboon brain, contrasting with previous results obtained in rats. Conversely, the regional distribution of 123I-INER was consistent with known distribution of NAT in baboon brain. No displacement of 123I-NKJ64 was observed following administration of reboxetine. This contrasts with previous data obtained for 123I-INER, where 60% of specific binding was displaced by a lower dose of reboxetine. These data suggest that 123I-NKJ64 may lack affinity and selectivity for NAT in baboon brain and 123I-INER is the most promising iodinated reboxetine analogue developed to date for in vivo imaging of NAT in brain using SPECT. This study highlights the importance of species differences during radiotracer development and the stereochemical configuration of analogues of reboxetine in vivo. Synapse, 2012. -® 2012 Wiley Periodicals, In