Predicted aircraft effects on stratospheric ozone

The possibility that the current fleet of subsonic aircraft may already have caused detectable changes in both the troposphere and stratosphere has raised concerns about the impact of such operations on stratospheric ozone and climate. Recent interest in the operation of supersonic aircraft in the lower stratosphere has heightened such concerns. Previous assessments of impacts from proposed supersonic aircraft were based mostly on one-dimensional model results although a limited number of multidimensional models were used. In the past 15 years, our understanding of the processes that control the atmospheric concentrations of trace gases has changed dramatically. This better understanding was achieved through accumulation of kinetic data and field observations as well as development of new models. It would be beneficial to start examining the impact of subsonic aircraft to identify opportunities to study and validate the mechanisms that were proposed to explain the ozone responses. The two major concerns are the potential for a decrease in the column abundance of ozone leading to an increase in ultraviolet radiation at the ground, and redistribution of ozone in the lower stratosphere and upper troposphere leading to changes in the Earth's climate. Two-dimensional models were used extensively for ozone assessment studies, with a focus on responses to chlorine perturbations. There are problems specific to the aircraft issues that are not adequately addressed by the current models. This chapter reviews the current status of the research on aircraft impact on ozone with emphasis on immediate model improvements necessary for extending our understanding. The discussion will be limited to current and projected commercial aircraft that are equipped with air-breathing engines using conventional jet fuel. The impacts are discussed in terms of the anticipated fuel use at cruise altitude

New insights into the protein aggregation pathology in myotilinopathy by combined proteomic and immunolocalization analyses

Introduction: Myofibrillar myopathies are characterized by progressive muscle weakness and impressive abnormal protein aggregation in muscle fibers. In about 10 % of patients, the disease is caused by mutations in the MYOT gene encoding myotilin. The aim of our study was to decipher the composition of protein deposits in myotilinopathy to get new information about aggregate pathology. Results: Skeletal muscle samples from 15 myotilinopathy patients were included in the study. Aggregate and control samples were collected from muscle sections by laser microdissection and subsequently analyzed by a highly sensitive proteomic approach that enables a relative protein quantification. In total 1002 different proteins were detected. Seventy-six proteins showed a significant over-representation in aggregate samples including 66 newly identified aggregate proteins. Z-disc-associated proteins were the most abundant aggregate components, followed by sarcolemmal and extracellular matrix proteins, proteins involved in protein quality control and degradation, and proteins with a function in actin dynamics or cytoskeletal transport. Forty over-represented proteins were evaluated by immunolocalization studies. These analyses validated our mass spectrometric data and revealed different regions of protein accumulation in abnormal muscle fibers. Comparison of data from our proteomic analysis in myotilinopathy with findings in other myofibrillar myopathy subtypes indicates a characteristic basic pattern of aggregate composition and resulted in identification of a highly sensitive and specific diagnostic marker for myotilinopathy. Conclusions: Our findings i) indicate that main protein components of aggregates belong to a network of interacting proteins, ii) provide new insights into the complex regulation of protein degradation in myotilinopathy that may be relevant for new treatment strategies, iii) imply a combination of a toxic gain-of-function leading to myotilin-positive protein aggregates and a loss-of-function caused by a shift in subcellular distribution with a deficiency of myotilin at Z-discs that impairs the integrity of myofibrils, and iv) demonstrate that proteomic analysis can be helpful in differential diagnosis of protein aggregate myopathies

Differential proteomic analysis of abnormal intramyoplasmic aggregates in desminopathy

Desminopathy is a subtype of myofibrillar myopathy caused by desmin mutations and characterized by protein aggregates accumulating in muscle fibers. The aim of this study was to assess the protein composition of these aggregates. Aggregates and intact myofiber sections were obtained from skeletal muscle biopsies of five desminopathy patients by laser microdissection and analyzed by a label-free spectral count-based proteomic approach. We identified 397 proteins with 22 showing significantly higher spectral indices in aggregates (ratio >1.8, p <0.05). Fifteen of these proteins not previously reported as specific aggregate components provide new insights regarding pathomechanisms of desminopathy. Results of proteomic analysis were supported by immunolocalization studies and parallel reaction monitoring. Three mutant desmin variants were detected directly on the protein level as components of the aggregates, suggesting their direct involvement in aggregate-formation and demonstrating for the first time that proteomic analysis can be used for direct identification of a disease-causing mutation in myofibrillar myopathy. Comparison of the proteomic results in desminopathy with our previous analysis of aggregate composition in filaminopathy, another myofibrillar myopathy subtype, allows to determine subtype-specific proteomic profile that facilitates identification of the specific disorder. Biological significance Our proteomic analysis provides essential new insights in the composition of pathological protein aggregates in skeletal muscle fibers of desminopathy patients. The results contribute to a better understanding of pathomechanisms in myofibrillar myopathies and provide the basis for hypothesis-driven studies. The detection of specific proteomic profiles in different myofibrillar myopathy subtypes indicates that proteomic analysis may become a useful tool in differential diagnosis of protein aggregate myopathies. This article is part of a Special Issue entitled: From Genome to Proteome: Open Innovations. (C) 2013 Elsevier B.V. All rights reserved

Ozon in Deutschland: Die Belastung durch Ozon in ländlichen Gebieten im Kontext der neuartigen Waldschäden

Jedes Jahr treten, bevorzugt während der Sommermonate, in Europa die sogenannten Photosmog Episoden auf. Dieses sind Peroden, an denen die Konzentrationen von Photooxidantien in der Luft auf ein Mehrfaches ihrer Durchschnittswerte anwachsen. Antizyklonale (Hochdruck) Wetterlagen mit hohen Temperaturen und erhöhter Einstrahlung, verbunden mit geringem Austausch von Luftmassen aus der atmosphärischen Grenzschicht mit der freien Troposphäre schaffen Bedingungen, bei denen die Oxidantionvorläufer ideale Bedingungen für chemische atmosphärische Reaktionen vorfinden. Die Oxidantienvorläufer sind Stickoxide und reaktive Kohlenwasserstoffe, für die es in Zentraleuropa hauptsächlich anthropogene Quellen gibt. Kraftverkehr und Kraftwerke ermittieren Stickoxide, Kraftverkehr und Industrie reaktive Kohlenwasserstoffe. Ozon (O$_{3}$ ist das wichtigste Photooxidant. Weitere im Photosmog vorkommende Oxidantien sind Stickstoffdioxid (NO$_{2}$, Wasserstoffperoxid (H$_{2}$O$_{2}$), Peroxyacetylnitrate (CH$_{3}$CO$_{3}$NO$_{2}$. Die in der Atmosphäre ablaufenden chemischen Reaktionen, die zur Bildung der Photooxidanten führen, sind in den Einzelheiten komplex. Jedoch ist die generelle Abfolge der Reaktionen wohl verstanden. In der Beschränkung auf die Ozonbildung verläuft sie wie folgt: [...

Messungen der Mischungsverhältnisse des Formaldehyds in belasteter Troposphäre mittels Spektroskopie mit abstimmbaren Diodenlasern : Untersuchungen zur Bedeutung des Formaldehyds für die Ozonproduktion aus Kfz-Abgasen

Formaldehyde concentrations were measured at the KFA campus near Jülich in order to obtain more detailed information on the importance of formaldehyde resulting from automobile exhaust concerning photochemical ozone production. A state-of-the art tunable diode laser (TDL) instrument (wavelength modulation, 2f-detection technique, time resolution 10 minutes) was designed and built. One single absorption line was found for the detection of formaldehyde without any interferences to other substances. The instrument was calibrated using a seif made permeation source and the linear response of the system was realized in the concentration range from 0 to 15 ppbV. During laboratory measurements detection limits of 200 to 300 pptV were achieved provided a signal to noise ratio of 1. The errors of rneasured formaldehyde mixing ratios were in the range from 15 to 25 %. Because of unstable laser-background conditions the mean detection limit was only 430 pptV during a field campaign conducted in summer 1994. Beside the concentrations of formaldehyde the concentrations of ozone, NO, NO$_{y}$ and 27 hydrocarbons were measured during this time under conditions of a typical photosmog period. The mixing ratios of formaldehyde ranged from 0.3 to 10 ppbV whereas those of ozone varied between 0 and 120 ppbV. Typical mean diurnal variations were observed for ozone with maximum concentrations in the earlyafternoon. Formaldehyde concentrations were found to increase from 1.5 ppbV in the early morning to 3 ppbV around afternoon. In contrast to ozone, the mean diurnal variation of formaldehyde showed a minimum in the late afternoon and a second increase after sunset. The influence of formaldehyde on photochemical ozone production was estimated with the help of caiculations using the Euro-RADM model where the initial conditions for the model runs were determined from results of the measurements. The calculations include differentiation between formaldehyde produced photochemically and formaldehyde coemitted with NO$_{x}$ by automobile exhaust. [...

The Euro-RADM mechanism: a gas-phase chemical mechanism for European air quality studies

In this report we present the Euro-RADM gas-phase chemical mechanism which was developed to model European atmospheric chemistry. It is based upon the Regional Acid Deposition Model Mechanism, version 2. Organic compounds typically measured at the Schauinsland field state were implemented into the RADM2 modelusing the review of Carter (1990). The primary chemistry ofthe measured VOCs and the yields of the secondary products were added to the RADM2 mechanism using the Carter review. The secondary chemistry of RADM2 remained unchanged except that the chemistry of the peroxy radical reactions was modified to account for the new product yields and the chemistry of PAN was updated to be consistent with recent laboratory measurements. The Euro-RADM mechanism is a much more complete parameterization of organic chemical species found at European field stations. A completely explicit approach would require the addition of an extremely large number of species to the mechanism. An explicit approach would not be practical because many of the required reactions and species have not been measured in laboratory experiments and the explicit mechanism would be too expensive and difficult to implement in a current 3-d transport/transformation model. The Euro-RADM mechanism was developed according to the principle that a mechanism should be no more detailed than justified by both laboratory and field measurement data. Laboratory and field measurement data are used to develop atmospheric chemical mechanisms. All mechanisms are in constant need of correction and improvements due to new scientific data. A priority for future development is to incorporate the most recent LACTOZ results into the Euro-RADM model. Recent LACTOZ results on the production of peroxides from the reactions of ozone and NO$_{3}$ with alkenes needs to be included in revised versions of the Euro-RADM mechanism. Aromatic oxidation reactions present an especially difficult problem because the secondary reactions of aromatics are poorly understood. Additional experimental data will be required before a completely reliable parameterization of aromatic chemistry can be incorporated into atmospheric chemistry mechanisms

Überprüfung der historischen "Schönbein Methode" zum Nachweis von Ozon in einem Strömungsrohr

Atmospheric ozone was measured during the second half of last century by means of the Schönbeintechnique. It employed a strip of filter paper impregnated withpotassium iodide and starch. Upon exposure to ambient air, the iodide was oxidized by the ozone to iodine and the well-known blue color from the complex betweeniodine and starch was used as a measure of the ozone concentration by comparison with a chromatic scale. It was known that the Schönbeintechnique was sensitive to the humidity of the air and possibly to the wind speed during exposure. We have tested the method in a flow tube for its response to O$_{3}$, wind speed, and relative humidity. In addition, the dependence of the coloration on exposure time was investigated. For O$_{3}$ concentrations below 10 ppb, the coloration increased proportinal with time for about 8 hours. Then, a plateau was reached that lasted for a few hours. Afterwards, the coloration disappeared with time of O$_{3}$ exposure due to losses of iodine from the paper. The initial slope and the coloration reached during the plateau depended on O$_{3}$ concentration and on humidity. Most important, the length of the plateau was considerably shorter and the decay of the coloration was much faster at higher O$_{3}$ levels. The results demonstrate that the Schönbeintechnique was ambiguous in the sense that, at the exposure times around 8 hours or more, as they were used during lastcentury, higher O$_{3}$ concentrations may have produced less coloration. Only under the assumption that the O$_{3}$ concentration during last century was around or below 10 ppb, the data could be used for evaluation of the O$_{3}$ distribution in the lower troposphere over Europe and the USA during last century. Moreover, quantitative assessments are difficult due to the poor standardization of the papers then used and because of the strong influence of humidity

Bestimmung von Emissionsraten pflanzlicher Kohlenwasserstoffe bei Sonnenblumen in Abhängigkeit von Temperatur, Lichtintensität und Streß, insbesondere von der Belastung mit Ozon

The emissionrates of isoprene, mono- and sesquiterpenes from sunflower ($\textit{Helianthus annuus L. cv. giganteus}$) were determined in an environmental chamber, a continuously stirred tank reactor. $\alpha$-pinene, $\beta$-caryophyllene and two oxygenated compounds (BOVOCs = Biogenie oxygenated volatile organic compounds; not yet identified) were emitted with rates in the range from 2 $\cdot$ 10$^{-16}$ to 4 $\cdot$ 10$^{-15}$ mol$\cdot$cm$^{-2} \cdot$s$^{-1}$ (cm$^{2}$ one sided leaf area) resp. 30 to 600 ng·per g dryweight and hour (ng$\cdot$g(dr)$^{-1} \cdot$h$^{-1}$). The emissionrates of isoprene, sabinene, $\beta$-pinene and limonene were about 1 to 8$\cdot$10$^{-16}$ mol$\cdot$cm$^{-2} \cdot$s$^{-1}$ (15 - 120 ng$\cdot$g(dr)$^{-1} \cdot$h$^{-1}$). The composition of the emitted VOCs showed a characteristical shape for this plant species. The emissionrates of all terpenes increased exponentially with temperature. The rate of increase in emission was about 5 to 40 %$\cdot$K$^{-1}$ and was more rapid than the increase of vapor pressure of the terpenes. Substance specific differences of the rate of increase of the emissionsrates were observed. For all substances the dependence of their emissionrates on temperature increased withincreasing light intensity. Increasing lightflux resulted in an increase of the emissionrates for all substances. The correlation between VOC-emissionrates and lightintensity yielded increases of emissionrates between 1 and 50$\cdot$10$^{-9}$ mol/Einstein. The raise of emission rates with lightflux was dependent on temperature and increased with increasing temperature. During periods without plant stress the emissionrates exhibited a good correlation with the rate of transpiration ($\Theta$(H$_{2}$O)) as weil as with the rate of net photosynthesis ($\Theta$(CO$_{2}$)). Ratios of emitted carbon per assimilated CO$_{2}$ were in the range of 0,002-0,01 % molC(VOC)/molC(CO$_{2}$). Sunflowers emitted higher amounts of terpenes when they were stressed by mechanical, wounding and Ozone treatment as weil as nutrient- or waterdeficiency. The emissionrates increased by a factor of 5 - 300. Exposure with Ozone had an effect on hydrocarbon emissionrates with a delay-time. 3 - 4 h after exposure with 25 - 120 ppb Ozone the emissionrates increased by a factor of 5 - 100. This increase was only observed on the first day of exposure. Nutrient deficiency resulted in an increase of emissionrates by a factor of 10 - 30 during the whole period when stress was hold on over several days. In situations of mechanical, wounding and Ozone stress, substance specific changes in the emissionspectrum were observed. The stress induced increased emissionrates often declined with time in an exponential manner. Values as before stress were reached after 3 - 10 h. A model was developed to explain the observed phenomena. It seems to be necessary to include biosynthesis of terpenes into models explaining biogenie emissions of hydrocarbons. In addition deposition rates of Ozone were measured. The main pathway of Ozone loss in the chamber is caused by the uptake through the stomata of the plants. However, up to 50 % of the Ozone loss must be explained by other pro ces ses indirectly caused by the plants. Reactions of Ozone with the measured VOCs can not explain these high loss rates for Ozone. [...