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  • 2010  (49)
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  • 2010  (49)
  • 1
    Language: English
    In: Science of the Total Environment, 2010, Vol.408(22), pp.5405-5413
    Description: The implementation of a geodata-based probabilistic pesticide exposure assessment for surface waters in Germany offers the opportunity to base the exposure estimation on more differentiated assumptions including detailed landscape characteristics. Since these characteristics can only be estimated using field surveys, water body width and depth, hydrology, riparian buffer strip width, ground vegetation cover, existence of concentrated flow paths, and riparian vegetation were characterised at 104 water body segments in the vineyard region Palatinate (south-west Germany). Water body segments classified as permanent (n = 43) had median values of water body width and depth of 0.9 m and 0.06 m, respectively, and the determined median width:depth ratio was 15. Thus, the deterministic water body model (width = 1 m; depth = 0.3 m) assumed in regulatory exposure assessment seems unsuitable for small water bodies in the study area. Only 25% of investigated buffer strips had a dense vegetation cover (〉 70%) and allow a laminar sheet flow as required to include them as an effective pesticide runoff reduction landscape characteristic. At 77 buffer strips, bordering field paths and erosion rills leading into the water body were present, concentrating pesticide runoff and consequently decreasing buffer strip efficiency. The vegetation type shrubbery (height 〉 1.5 m) was present at 57 (29%) investigated riparian buffer strips. According to their median optical vegetation density of 75%, shrubberies may provide a spray drift reduction of 72 ± 29%. Implementing detailed knowledge in an overall assessment revealed that exposure via drift might be 2.4 and via runoff up to 1.6 fold higher than assumed by the deterministic approach. Furthermore, considering vegetated buffer strips only by their width leads to an underestimation of exposure by a factor of as much as four. Our data highlight that the deterministic model assumptions neither represent worst-case nor median values and therefore cannot simply be adopted in a probabilistic approach.
    Keywords: Probabilistic Exposure Assessment ; Pesticide ; Exposure ; Riparian Buffer Strips ; Field Survey ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 2
    Language: English
    In: Environmental Pollution, 2010, Vol.158(2), pp.615-623
    Description: This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species ( and ) and two emergent rooted species ( and ) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing. Simazine at concentrations of 0.05 mg/L does not cause long-term negative effects to aquatic macrophytes or algae.
    Keywords: Macrophytes ; Single-Species ; Microcosms ; Herbicide ; Simazine ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 3
    Language: English
    In: Environmental pollution, 2010, Vol.158, pp.615-623
    Description: This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing. Simazine at concentrations of 0.05 mg/L does not cause long-term negative effects to aquatic macrophytes or algae. ; Includes references ; p. 615-623.
    Keywords: Toxicity Testing ; Water Quality ; Simazine ; Phytoplankton ; Plant Growth ; Macrophytes ; Water Pollution
    ISSN: 0269-7491
    Source: AGRIS (Food and Agriculture Organization of the United Nations)
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  • 4
    Language: English
    In: Optics express, 12 April 2010, Vol.18(8), pp.8422-9
    Description: Mesoscopic Epifluorescence Tomography (MEFT) is a technique derived from Laminar Optical Tomography (LOT), determining fluorescence biodistribution by tomographic means in reflectance geometry. A pencil beam is scanned over the region of interest to excite fluorophores hidden within the tissue, while a CCD camera acquires images of reflected fluorescence emissions. This configuration is advantageous whenever transillumination of the specimen is not feasible, e.g., in the presence of skin chambers or when using wavelengths in the visible range where absorption is high. We present simulation and phantom studies recovering deep GFP-like fluorescence in highly scattering and strongly absorbing media with a penetration depth up to 10mm.
    Keywords: Scattering, Radiation ; Tomography, Optical -- Methods
    E-ISSN: 1094-4087
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  • 5
    Language: English
    In: Ecotoxicology and Environmental Safety, 2010, Vol.73(7), pp.1674-1680
    Description: Current aquatic environmental risk assessment of plant protection products or biocides does not consider effects on organisms involved in leaf litter breakdown, a fundamental ecosystem process in streams. Therefore, direct ecotoxicological implications of tebuconazole, a frequently used triazole fungicide, on the leaf-shredding amphipod , were assessed. While acute toxicity was low (96h-LC =1347 μg/L), feeding rate, a sublethal endpoint, was significantly reduced after seven days of exposure to 600 μg/L. At the same concentration, but during a three week exposure under semi-static conditions, gammarids showed significant reductions in feeding, but also in assimilation and growth. At 200 μg/L, however, only assimilation was significantly affected. As these endpoints can be used to evaluate the ecotoxicity of a broad range of chemicals and to deduce possible implications in the functioning of ecosystems, the inclusion of similar experimental set-ups might further improve aquatic environmental risk assessment.
    Keywords: Gammarus ; Shredder ; Triazole Fungicide ; Sublethal Endpoints ; Environmental Risk Assessment ; Confidence Interval Testing ; Ecology ; Public Health
    ISSN: 0147-6513
    E-ISSN: 1090-2414
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  • 6
    Language: English
    In: Journal of Cardiovascular Magnetic Resonance, 01 June 2010, Vol.12(1), p.36
    Description: Abstract Background The orifice area of mitral bioprostheses provides important information regarding their hemodynamic performance. It is usually calculated by transthoracic echocardiography (TTE), however, accurate and reproducible determination may be challenging. Cardiovascular magnetic resonance (CMR) has been proven as an accurate alternative for assessing aortic bioprostheses. However, whether CMR can be similarly applied for bioprostheses in the mitral position, particularly in the presence of frequently coincident arrhythmias, is unclear. The aim of the study is to test the feasibility of CMR to evaluate the orifice area of mitral bioprostheses. Methods CMR planimetry was performed in 18 consecutive patients with mitral bioprostheses (n = 13 Hancock®, n = 4 Labcore®, n = 1 Perimount®; mean time since implantation 4.5 ± 3.9 years) in an imaging plane perpendicular to the transprosthetic flow using steady-state free-precession cine imaging under breath-hold conditions on a 1.5T MR system. CMR results were compared with pressure half-time derived orifice areas obtained by TTE. Results Six subjects were in sinus rhythm, 11 in atrial fibrillation, and 1 exhibited frequent ventricular extrasystoles. CMR image quality was rated as good in 10, moderate in 6, and significantly impaired in 2 subjects. In one prosthetic type (Perimount®), strong stent artifacts occurred. Orifice areas by CMR (mean 2.1 ± 0.3 cm2) and TTE (mean 2.1 ± 0.3 cm2) correlated significantly (r = 0.94; p 〈 0.001). Bland-Altman analysis showed a 95% confidence interval from -0.16 to 0.28 cm2 (mean difference 0.06 ± 0.11 cm2; range -0.1 to 0.3 cm2). Intra- and inter-observer variabilities of CMR planimetry were 4.5 ± 2.9% and 7.9 ± 5.2%. Conclusions The assessment of mitral bioprostheses using CMR is feasible even in those with arrhythmias, providing orifice areas with close agreement to echocardiography and low observer dependency. Larger samples with a greater variety of prosthetic types and more cases of prosthetic dysfunction are required to confirm these preliminary results.
    Keywords: Medicine
    ISSN: 1097-6647
    E-ISSN: 1532-429X
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  • 7
    In: Medical Physics, May 2010, Vol.37(5), pp.1976-1986
    Description: Purpose: The performance is studied of two newly introduced and previously suggested methods that incorporate priors into inversion schemes associated with data from a recently developed hybrid x-ray computed tomography and fluorescence molecular tomography system, the latter based on CCD camera photon detection. The unique data set studied attains accurately registered data of high spatially sampled photon fields propagating through tissue along 360 deg. projections. Methods: Approaches that incorporate structural prior information were included in the inverse problem by adding a penalty term to the minimization function utilized for image reconstructions. Results were compared as to their performance with simulated and experimental data from a lung inflammation animal model and against the inversions achieved when not using priors. Results: The importance of using priors over stand-alone inversions is also showcased with high spatial sampling simulated and experimental data. The approach of optimal performance in resolving fluorescent biodistribution in small animals is also discussed. Conclusions: Inclusion of prior information from x-ray CT data in the reconstruction of the fluorescence biodistribution leads to improved agreement between the reconstruction and validation images for both simulated and experimental data. Journal Article.
    Keywords: Computed Tomography ; Visual Imaging ; Reconstruction ; X‐Ray Imaging ; Image Reconstruction; Tomography ; Biomedical Optical Imaging ; Ccd Image Sensors ; Computerised Tomography ; Fluorescence ; Image Reconstruction ; Inverse Problems ; Lung ; Medical Image Processing ; Optical Tomography ; Physiological Models ; Fluorescence Molecular Tomography ; Hybrid Imaging ; Reconstruction ; Multimodality ; X‐Ray Ct ; Medical Imaging ; Lungs ; Fluorescence ; Medical Image Reconstruction ; Medical X‐Ray Imaging ; Computed Tomography ; Optical Properties ; Image Reconstruction ; Tissues ; Charge Coupled Devices
    ISSN: 0094-2405
    E-ISSN: 2473-4209
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  • 8
    Language: English
    In: Journal of biomedical optics, 2010, Vol.15(3), pp.036006
    Description: The recent development of hybrid imaging scanners that integrate fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) allows the utilization of x-ray information as image priors for improving optical tomography reconstruction. To fully capitalize on this capacity, we consider a framework for the automatic and fast detection of different anatomic structures in murine XCT images. To accurately differentiate between different structures such as bone, lung, and heart, a combination of image processing steps including thresholding, seed growing, and signal detection are found to offer optimal segmentation performance. The algorithm and its utilization in an inverse FMT scheme that uses priors is demonstrated on mouse images.
    Keywords: Algorithms ; Image Processing, Computer-Assisted -- Methods ; Spectrometry, Fluorescence -- Methods ; Tomography, X-Ray Computed -- Methods
    ISSN: 10833668
    E-ISSN: 1560-2281
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  • 9
    Language: English
    In: Environmental science & technology, 01 March 2010, Vol.44(5), pp.1728-35
    Description: An analytical method was developed for the determination of nine antiviral drugs (acyclovir, abacavir, lamivudine, nevirapine oseltamivir, penciclovir, ribavirin, stavudine, zidovudine) and one active metabolite (oseltamivir carboxylate) in raw and treated wastewater as well as in surface water using LC/ESI tandem MS detection. Relative recoveries exceeded 80% and limits of quantification ranged between 0.2 and 10 ng L(-1). Matrix effects were compensated by the use of stable isotope labeled surrogate standards and optimized chromatographic separation on a Hydro-RP column. All antiviral drugs, except ribavirin, were detected in raw wastewater. A significant reduction in concentrations was observed for acyclovir, lamivudine, and abacavir in treated wastewater indicating a substantial removal, while nevirapine, zidovudine and oseltamivir were found in similar concentrations in raw and treated wastewater. Concentrations in river waters were in the lower ng L(-1)-range, with a maximum of 190 and 170 ng L(-1) for acyclovir and zidovudine, respectively in the Hessian Ried. Estimated total compound loads in the Ruhr river ranged between 〈0.1 and 16.5 g d(-1) while for the Rhine river values between 370 and 1800 g d(-1) were determined. The ratios of oseltamivir to oseltamivir carboxylate were approximately a factor of 10 higher for the Rhine than for the other rivers and streams indicating a significant contribution from other sources such as discharges from manufacturing facilities.
    Keywords: Antiviral Agents -- Analysis ; Environmental Monitoring -- Methods ; Fresh Water -- Analysis ; Water Pollutants, Chemical -- Analysis
    ISSN: 0013-936X
    E-ISSN: 15205851
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  • 10
    Language: English
    In: IEEE transactions on medical imaging, February 2010, Vol.29(2), pp.465-73
    Description: A hybrid imaging system for simultaneous fluorescence tomography and X-ray computed tomography (XCT) of small animals has been developed and presented. The system capitalizes on the imaging power of a 360 ( degrees )-projection free-space fluorescence tomography system, implemented within a microcomputed tomography scanner. Image acquisition is based on techniques that automatically adjust a series of imaging parameters to offer a high dynamic range dataset. Image segmentation further allows the incorporation of structural priors in the optical reconstruction problem to improve the imaging performance. The functional system characteristics are showcased, and images from a brain imaging study are shown, which are reconstructed using XCT-derived priors into the optical forward problem.
    Keywords: Image Processing, Computer-Assisted -- Methods ; X-Ray Microtomography -- Methods
    ISSN: 02780062
    E-ISSN: 1558-254X
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