Altitude and Latitude Distribution of Atmospheric Aerosol and Water Vapor from the Narrow-Band Lunar Eclipse Photometry

The work contains the description of two narrow IR-bands observational data of total lunar eclipse of March, 3, 2007, one- and two-dimensional procedures of radiative transfer equation solution. The results of the procedure are the extinction values for atmospheric aerosol and water vapor at different altitudes in the troposphere along the Earth's terminator crossing North America, Arctic, Siberia and South-Eastern Asia. The altitude range and possible latitude and altitude resoltion of atmosphere remote sensing by the lunar eclipses observation are fixed. The results of water vapor retrieval are compared with data of space experiment, the scale of vertical water vapor distribution is found.Comment: 12 pages, 7 figures, submitted to Journal of Quantitative Spectroscopy and Radiative Transfe

Nighttime removal of NOx in the summer marine boundary layer

The nitrate radical, NO3, and dinitrogen pentoxide, N2O5, are two important components of nitrogen oxides that occur predominantly at night in the lower troposphere. Because a large fraction of NO2 reacts to form NO3 and N2O5 during the course of a night, their fate is an important determining factor to the overall fate of NOx (=NO and NO2). As a comprehensive test of nocturnal nitrogen oxide chemistry, concentrations of O3, NO, NO2, NO3, N2O5, HNO3 and a host of other relevant compounds, aerosol abundance and composition, and meteorological conditions were measured in the marine boundary layer from the NOAA research vessel Ronald H. Brown off the East Coast of the United States as part of the New England Air Quality Study (NEAQS) during the summer of 2002. The results confirm the prominent role of NO3 and N2O5 in converting NOx to HNO3 at night with an efficiency on par with daytime photochemical conversion. The findings demonstrate the large role of nighttime chemistry in determining the NOx budget and consequent production of ozone. INDEX TERMS: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry. Citation: Brown, S. S., et al. (2004), Nighttime removal of NOx in the summer marine boundary layer, Geophys. Res. Lett., 31, L07108, doi:10.1029/2004GL01941

HLA polymorphism : genomic typing and impact on unrelated stem cell transplantation

The HLA (Human Leukocyte Antigen) region is the most polymorphic in the human genome. The extended polymorphism contributes to the ability both of individuals and populations to combat diversity in the pathogens to which they are exposed. The region was first discovered through its influence on transplantation rejection and on antigen-specific immune responses. Today, we know that HLA molecules are receptors for peptides derived from self and foreign antigens, which are captured within the cleft of the HLA molecule and presented to T cells. The interaction between the T cell receptor (TCR) and the MHCpeptide complex is a first step in the activation of the T cell. In clinical transplantation HLA incompatibilities between patient and donor leads to an immune response directed against the transplanted cells (host versus graft reaction) or in stem cell transplantation, against the cells of the recipient in immunodeficient patients (graft versus host reaction, GVHD). Initially, the HLA antigens were defined using serological typing techniques. However, human alloantisera are of limited value when detecting allelic variation located deep within the cleft of the HLA molecules which is inaccessible to antibodies. Consequently, many polymorphisms in HLA molecules can be serologically silent or undetectable by allotypic antisera. During the last few years DNA based typing techniques have begun to replace the serological techniques in clinical applications. Initially, the DNA methods were applied to class 11 typing, but more recently they have been used to determine class I alleles as well. We have developed a polymerase chain reaction-based technique, using sequence-specific primers (PCR-SSP) for HLA class I and class 11 typing. In this thesis PCR- SSP typing is described for the DQB 1, DPA 1 and DPB 1 loci. The recent use of DNA based typing techniques has resulted in many new HLA alleles being identified. One new allele, DQB 1*0609, which was found during the development of DQB1-typing by PCR-SSP, is described here. Finally, we have, retrospectively, studied the correlation between the grade of HLA matching and the outcome of the transplantation, in patients receiving stem cells from unrelated donors. We found a high frequency of severe GVHD and a high mortality rate in patients receiving HLA-B allele level mismatched stem cells. We also found that patients that received stem cells from donors mismatched for HLA-C, as well as for the NK cell KIR ligand motif had a decreased survival and decreased disease- free survival. Finally, we observed that patients receiving DPA1 mismatched stem cells had decreased survival and relapse-free survival (RFS), which indicates that DPA1 polymorphism is immunologically relevant in stem cell transplantation. These patients also had an increased frequency of relapses. In conclusion, genomic HLA class I and II typing adds substantially to the success of transplantation of hematopoetic stem cells from unrelated donors. The awareness of HLA class I and II mismatches in a recipient-donor pair form the basis for the appropriate preand post-transplantation treatment, which will improve the outcome of the transplantation

Measurement of radioxenon and radioargon in air from soil with elevated uranium concentration

Among the most important indicators for an underground nuclear explosion are the radioactive xenon isotopes 131mXe, 133Xe, 133mXe and 135Xe and the radioactive argon isotope 37Ar. In order to evaluate a detection of these nuclides in the context of a nuclear test verification regime it is crucial to have knowledge about expected background concentrations. Sub soil gas sampling was carried out on the oil shale ash waste pile in Kvarntorp, Sweden, a location with known elevated uranium content where 133Xe and 37Ar were detected in concentrations up to 120 mBq/m3 and 40 mBq/m3 respectively. These data provides one of the first times when xenon and argon were both detected in the same sub soil gas. This, and the correlations between the radionuclides, the sub soil gas contents (i.e. CO2, O2, and radon) and uranium concentration in the pile, provide very interesting information regarding the natural background and the xenon concentration levels and can most likely be used as an upper limit on what to be expected naturally occurring

Nanosecond and femtosecond probing of the dynamics of the UV-photodissociation of perfluoroethyliodide C2F5I

The ns photodissociation of perfluoroethyliodide C2F5I at 266 nm has been studied by using the resonant two-photon ionization (R2PI) technique. Recoil anisotropy parameters as well as average translational energy of the I atoms in the fine structure states P-2(1/2) and P-2(3/2) have been determined. The main contribution (99%) to the absorption at 266 nm was found to be caused by a parallel transition to the (3)Q(0) state which gives mainly excited-state atoms I(P-2(1/2)). The ground-state atoms I(P-2(3/2)) were found to appear mainly (88%) from the primarily excited (3)Q(0) state via curve-crossing (3)Q(0)-(1)Q(1) and to a lesser extent (12%) from direct absorption by a perpendicular transition to the (1)Q(1) and (3)Q(1) states. The fs pump-dump technique in combination with ns R2PI probing of the fragments I(P-2(1/2)) and I(P-2(3/2)) and time-of-flight mass spectrometry have been applied to probe the early stage dynamics of the C2F5I molecule on the excited state (3)Q(0) potential energy surface (PES). The evolution time of the excited molecule to the point where the energy gap between the excited state (3)Q(0) and the ground-state potential energy surfaces drops to a value of about 12 440 cm-1 was found to be 52 +/- 13 fs. This time corresponds to about 0.8 Angstrom extension of the C-I bond distance. The molecular dynamics simulation with DFT calculated ground-state PES and (3)Q(0) PES with the shape calculated for methyl iodide found in the literature gives reasonable agreement with the experimental result for the evolution time. (C) 2001 American Institute of Physics

Overtone Dissociation of Peroxynitric Acid (HO 2 NO 2 ): Absorption Cross Sections and Photolysis Products †

International audienceBand strengths for the second (3νOH) and third (4νOH) overtones of the OH stretch vibration of peroxynitric acid, HO2NO2 (PNA) in the gas-phase were measured using Cavity Ring-Down Spectroscopy (CRDS). Both OH overtone transitions show diffuse smoothly varying symmetrical absorption profiles without observable rotational structure. Integrated band strengths (base e) at 296 K were determined to be S3νOH ) (5.7 ( 1.1) × 10-20 and S4νOH ) (4.9 ( 0.9) × 10-21 cm2 molecule-1 cm-1 with peak cross sections of (8.8 ( 1.7) × 10-22 and (7.0 ( 1.3) × 10-23 cm2 molecule-1 at 10086.0 ( 0.2 cm-1 and 13095.8 ( 0.4 cm-1, respectively, using PNA concentrations measured on line by Fourier-transform infrared and ultraviolet absorption spectroscopy. The quoted uncertainties are 2σ (95% confidence level) and include estimated systematic errors in the measurements. OH overtone spectra measured at lower temperature, 231 K, showed a narrowing of the 3νOH band along with an increase in its peak absorption cross section, but no change in S3νOH to within the precision of the measurement ((9%). Measurement of a PNA action spectrum showed that HO2 is produced from second overtone photodissociation. The action spectrum agreed with the CRDS absorption spectra. The PNA cross sections determined in this work for 3νOH and 4νOH will increase calculated atmospheric photolysis rates of PNA slightly

USE OF CAVITY RING DOWN SPECTROSCOPY IN ATMOSPHERIC STUDIES

Author Institution: National Oceanic and Atmospheric Administration, Aeronomy Laboratory; The Cooperative Institute for Research in Environmental Sciences, and The Department of Chemistry and Biochemistry, University of ColoradoThe Cavity ringdown spectroscopy is a very versatile tool that has found many applications in the studies of the atmosphere. I will describe the use of CRDS in laboratory studies of atmospheric chemistry and photochemistry, measurements of NO3 and N2O5 in the atmosphere, quantification of aerosol extintion, and measurements of absorption cross sections needed for climate studies. The relevant atmospheric processes will be described and the needed information will be discussed. Examples of the relevant information from our laboratory studies will be presented

Measurement of radioxenon and radioargon in soil gas collected in the region of Kvarntorp, Sweden

Over 40 soil gas samples were collected both in post-industrial areas as well as in undisturbed areas in the region of Kvarntorp, Sweden. Radioxenon (133Xe) was detected in 15 samples and radioargon was detected in 7 from 10 samples analysed. The concentration of radioxenon and radioargon in soil gas ranged up to 109 mBq/m3 and 19 mBq/m3, respectively. During sample collection other soil gases such as radon, CO2 and O2 were also measured and soil samples were taken along with dose rate measurements. The field experiment presented here shows that it is possible to detect naturally occurring radioxenon and radioargon in soil gas simultaneously