The heterogeneous reaction of HNO3on mineral dust and γ-alumina surfaces: a combined Knudsen cell and DRIFTS study

Seisel, Sabine; Börensen, Christoph; Vogt, Rainer; Zellner, R.

doi:10.1039/b410793d

Cited by 42 publications

(76 citation statements)

References 39 publications

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“…The split of this degeneration has been observed before, especially for nitrate in an adsorbed state (Vogt and Finlayson-Pitts, 1994). It is caused by a non-symmetric environment (Nakamoto, 1997) and due to the observed small split of 100 cm −1 the two adsorption peaks at 1350 and 1452 cm −1 are clearly assigned to the nitrate ion (Seisel et al, 2004a). Evacuating the reaction cell as well as heating the reacted sample to 470 K did not change the intensity of the absorption bands, indicating that strongly bounded nitrate is irreversibly formed during the uptake of N 2 O 5 onto Saharan dust.…”

Section: Condensed-phase Productsmentioning

confidence: 78%

“…The experiment has already been described in the literature (Seisel et al, 2004a). In the present paper we will therefore only describe the main features of the technique as pertinent to the present study.…”

Section: Knudsen Cell Reactor (Kc)mentioning

confidence: 99%

“…It was found, that the interaction of NO y (HNO 3 +NO 3 +N 2 O 5 ) species with mineral dust particles may lead to a global ozone reduction of approximately 5% (Bauer et al, 2004). Evidence for the occurrence of such reactions comes from field experiments as well as from laboratory studies (Hanke et al, 2003;Usher et al, 2003;Putaud et al, 2004;Seisel et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

“…The experimental set-up has been described in detail elsewhere, (Börensen et al, 2000;Seisel et al, 2004a) and only the most relevant features will be described here. The sample compartment of the FTIR-spectrometer houses the reaction cell equipped with a DRIFTS optic and a sample holder.…”

Section: Diffuse Reflectance Infrared Spectroscopy (Drifts)mentioning

confidence: 99%

“…The integrated absorption bands of the products were calibrated absolutely by analysing the sample by ion chromatography after reaction (Seisel et al, 2004a). In order to account for a possible nitrate background in the mineral dust, reference samples have been analyzed where a nitrate background of 3.4·10 17 ions g −1 has been found.…”

Section: Diffuse Reflectance Infrared Spectroscopy (Drifts)mentioning

confidence: 99%

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Kinetics and mechanism of the uptake of N2O5 on mineral dust at 298 K

Seisel

Börensen²,

Vogt³

et al. 2005

Atmos. Chem. Phys.

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Abstract. The heterogeneous reaction of N 2 O 5 with mineral (Saharan) dust has been studied at T=298 K using a combination of Knudsen and DRIFTS cells for kinetic and product investigations, respectively. The initial uptake coefficient has been determined to be γ =(8.0±0.3)·10 −2 . This uptake slowly saturates into a steady state uptake of γ =(1.3±0.3)·10 −2 suggesting that reaction of N 2 O 5 with the mineral dust surface and hydrolysis of N 2 O 5 on the surface take place simultaneously. Both uptake coefficients have been calculated on the basis of the geometric (projected) surface area of the sample and must therefore be regarded as upper limits. In addition, the product investigations show that N 2 O 5 is irreversibly taken up to form nitrate on the surface. Recent model calculations suggest that the uptake rates of N 2 O 5 on Saharan dust which we measured may be large enough to influence the photo-oxidant budget of the atmosphere.

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Section: Condensed-phase Productsmentioning

confidence: 78%

Section: Knudsen Cell Reactor (Kc)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Diffuse Reflectance Infrared Spectroscopy (Drifts)mentioning

confidence: 99%

Section: Diffuse Reflectance Infrared Spectroscopy (Drifts)mentioning

confidence: 99%

See 3 more Smart Citations

Kinetics and mechanism of the uptake of N2O5 on mineral dust at 298 K

Seisel

Börensen²,

Vogt³

et al. 2005

Atmos. Chem. Phys.

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Chemie von Aerosolen

Hoffmann

Zetzsch

Rossi

2007

Chemie in nserer Zeit

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Atmospheric aerosols are not chemical inert airborne particles whose formation mechanisms, residence time or function in the atmosphere just dependent from mechanical or physical processes. In the course of the aerosol formation process as well as during their stay and transport in the atmosphere chemical reactions play an essential role. Chemical reactions take place at the surface and within aerosol particles and can not only influence gas phase chemistry, e.g. by serving as a reaction media for otherwise slow gas phase reactions, they can also alter the physico-chemical properties of the particles, e.g. their function as cloud condensation nuclei. This review summaries the current knowledge about the chemistry of aerosol, focusing on secondary aerosol formation processes and heterogeneous chemistry of sea salt, dust and soot particles

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Neuropilin‐1 is required for endothelial tip cell guidance in the developing central nervous system

Gerhardt

Ruhrberg

Abramsson

et al. 2004

Developmental Dynamics

238

196

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Recent evidence indicates that sprouting angiogenesis in the central nervous system (CNS) is a guided process similar to the guidance of axons and insect tracheal tubes. Specialized tip cells of vessel sprouts navigate in response to local depots or gradients of vascular endothelial growth factor (VEGF-A). Neuropilin-1 (Nrp-1) is a transmembrane receptor with a repulsive function in axon guidance. Nrp-1 also binds the VEGF-A splice isoform VEGF165, stimulates angiogenesis, and is necessary for vascular development in the mouse. However, the morphogenetic events controlled by Nrp-1 in angiogenesis have not been defined. Here, we analyzed endothelial tip cell guidance in the CNS of Nrp-1-deficient mice. We focused our attention on the developing hindbrain, which is normally vascularized in a stereotyped manner. Initially, angiogenic sprouts extend along radial glia from the pial surface toward the ventricles, but in the subventricular zone (SVZ), they leave the radial path, turn laterally, and fuse to form a capillary plexus. Radial sprout elongation correlated with tip cell filopodia extensions along nestin-positive radial glial processes, but in the SVZ, the tip cell filopodia also extended perpendicular to the glial tracks and made contact with filopodia of the neighboring sprouts. In Nrp-1-deficient mice, the tip cell filopodia remained associated with the radial glia in the SVZ, which correlated with a failure of sprout turning and elongation across this region. As a result, the sprouts remained blind-ended forming glomeruloid tufts in the SVZ. These observations suggest that Nrp-1 plays an important role in allowing the endothelial tip cell filopodia to switch substrate and protrude in a new direction at a specific location in the developing brain. Developmental Dynamics 231:503-509, 2004.

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The heterogeneous reaction of HNO₃on mineral dust and γ-alumina surfaces: a combined Knudsen cell and DRIFTS study

Cited by 42 publications

References 39 publications

Kinetics and mechanism of the uptake of N<sub>2</sub>O<sub>5</sub> on mineral dust at 298 K

Kinetics and mechanism of the uptake of N<sub>2</sub>O<sub>5</sub> on mineral dust at 298 K

Chemie von Aerosolen

Neuropilin‐1 is required for endothelial tip cell guidance in the developing central nervous system

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The heterogeneous reaction of HNO3on mineral dust and γ-alumina surfaces: a combined Knudsen cell and DRIFTS study

Cited by 42 publications

References 39 publications

Kinetics and mechanism of the uptake of N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; on mineral dust at 298 K

Kinetics and mechanism of the uptake of N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; on mineral dust at 298 K

Chemie von Aerosolen

Neuropilin‐1 is required for endothelial tip cell guidance in the developing central nervous system

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Product

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The heterogeneous reaction of HNO₃on mineral dust and γ-alumina surfaces: a combined Knudsen cell and DRIFTS study

Kinetics and mechanism of the uptake of N<sub>2</sub>O<sub>5</sub> on mineral dust at 298 K

Kinetics and mechanism of the uptake of N<sub>2</sub>O<sub>5</sub> on mineral dust at 298 K