Novel Loci for Adiponectin Levels and Their Influence on Type 2 Diabetes and Metabolic Traits : A Multi-Ethnic Meta-Analysis of 45,891 Individuals

J. Kaprio, S. Ripatti ja M.-L. Lokki työryhmien jäseniä.Peer reviewe

Measurement of the Photodissociation Coefficient of NO2 in the Atmosphere: II. Stratospheric Measurements

The photodissociation coefficient of NO2, J NO 2, has been measured from a balloon platform in the stratosphere. Results from two balloon flights are reported. High Sun values of J NO 2 measured were 10.5±0.3 and 10.3±0.3×10-3 s-1 at 24 and 32 km respectively. The decrease in J NO 2 at sunset was monitored in both flights. The measurements are found to be in good agreement with calculations of J NO 2 using a simplified isotropic multiple scattering computer routine

Partitioning of Reactive Atmospheric Nitrogen Oxides at an Elevated Site in Southern Quebec, Canada

Measurements of the major reactive nitrogen oxides including NO, NO2, HNO3, particulate nitrate, PAN, and NOy, as well as O3 and supporting meteorology, were made at an elevated site (845 masl) in the rural eastern townships of Quebec, Canada, from February 1998 to October 1999. NOx (and NOy) mixing ratios exhibited a distinct seasonal cycle with median NOx levels in winter more than a factor of 4 greater than in summer. Seasonal partitioning indicated that NOx was the dominant fraction of NOy during winter (>70%), with HNO3 and PAN fractions of <18 and 9%, respectively. The NOy reservoir in summer consisted of average contributions from NOx, HNO3, and PAN of 35, 20–25, and 13%, respectively. A NOy deficit of the order of 25–30% was observed during spring and summer that could not be explained by measurement uncertainties or potential interferences. It is possible that there were other reactive nitrogen species in the atmosphere that were not separately measured that contributed to the NOy deficit. Indications are that these compounds were photochemically produced and present in highly processed air masses

Optimized operation and calibration procedures for radical amplifier type dectors

Laboratory experiments were conducted to improve the operation and calibration procedures for the ambient ROx radical detectors (ROx = HO2 + RO2 + OH + RO) based on chemical amplification. A new method for the experimental determination of the effective ratio between the absorption cross sections for water and molecular oxygen at 184.9 nm was developed and used to reduce the uncertainties associated with the peroxy radical source based on water photolysis. A novel peroxy radical source based on OCIO was developed and employed to confirm the ambient humidity effect on the chain length of the radical detector. The humidity effect on the chain length can be reduced by heating the walls of the reactor and decreasing the residence time of the air sample in the reactor to avoid the possible interferences from thermolabile species

Nitrogen and sulphur over the Western Atlantic Ocean

This paper reports new surface and aircraft measurements of sulphur and nitrogen species made during WATOX-85 at Lewes, Delaware and Bermuda. Concentrations of most species measured in this portion of the western Atlantic Ocean atmosphere were higher than those found in remote marine environments, showing clearly the influence of anthropogenic emissions from North America. The experiment was designed such that measurements were made following cold frontal passages in conditions of strong, dry westerly flow, to ensure that measurements at Bermuda were in air masses that had earlier crossed the east coast in the region of Lewes. Boundary-layer SO2 concentrations decreased by a factor of 20 between the east coast and Bermuda, while sulphate was the same at both locations. First-order decay distances for SO2 and total S were 340 and 620 km, respectively, under these conditions. The decay distance for total S is substantially shorter than previously determined, indicating that SO2 in particular is removed in near-coastal environments more quickly than previously supposed. Boundary-layer NOx and HNO3 concentrations decreased by close to an order of magnitude between the east coast and Bermuda, whereas for NO3− the decrease was a factor of two. Corresponding first-order decay distances of NO'x and total N were 500 and 550km, respectively

A laboratory flow reactor with gas particle separation and on-line MS/MS for product identification in atmospherically important reactions

A system to study the gas and particle phase products from gas phase hydrocarbon oxidation is described. It consists of a gas phase photochemical flow reactor followed by a diffusion membrane denuder to remove gases from the reacted products, or a filter to remove the particles. Chemical analysis is performed by an atmospheric pressure chemical ionization (APCI) triple quadrupole mass spectrometer. A diffusion membrane denuder is shown to remove trace gases to below detectable limits so the particle phase can be studied. The system was tested by examining the products of the oxidation of m-xylene initiated by HO radicals. Dimethylphenol was observed in both the gas and particle phases although individual isomers could not be identified. Two furanone isomers, 5-methyl-2(3H)furanone and 3-methyl-2(5H)furanone were identified in the particulate phase, but the isobaric product 2,5 furandione was not observed. One isomer of dimethyl-nitrophenol was identified in the particle phase but not in the gas phase.NSERC, CFCAS, MO

The Production of Atmospheric NO2 and N2O from a Fertilized Agricultural Soil

The source strength of atmospheric trace gases from rural or remote locations must be quantified in order to assess the effect of such inputs on the background tropospheric chemistry. To assess the importance of biological production of NOx and N2O from fertilized agricultural soil, enclosure techniques have been used to determine the emission fluxes of NOx and N2O at a site in Southern Ontario, Canada. NOx fluxes on the unfertilized soil range from 1.5 to 41.6 μg(NO) m−2 h−1. The corresponding N2O fluxes are 0–61.8 μg(N2O)m−2h−1. For the most fertilized soil NOx fluxes range from 3.1 to 583 μg(NO) m−2h−1 and the N2O fluxes from 0 to 446 μg(N2O) m−2h−1. The fluxes increase linearly with fertilizer application, with 11% of the nitrogen in the fertilizer converted to NOx and 5% to N2O. The emission rates were studied as functions of the soil parameters temperature, moisture, ammonium, nitrate and pH, to attempt to understand better the production mechanisms, although a model for the process could not be developed. In rural areas away from transportation corridors the increased NOx emission from fertilized soil may dominate local oxidant production but is not significant on the Province-wide scal

Radical loss in a chain reaction of CO and NO in the presence of water: Implications for the radical amplifier and atmospheric chemistry

Atmospheric pressure rate coefficients for the loss of HO2, CH3O2, and C2H5O2 radicals to the wall of a ¼ Teflon tube have been measured. In dry air, they are 2.8 ± 0.2 s-1 for HO2 and 0.8 ± 0.1 s-1 for both CH3O2 and C2H5O2 radicals. The rate coefficient for HO2 loss increases markedly with the relative humidity of the air; however, the organic radicals show no such dependence. These data are used in a kinetic model of the radical amplifier chemistry to investigate the reported sensitivity to water concentration. The increased wall loss accounts for only some of the observed water dependence, suggesting there is an unreported water contribution to the gas phase chemistry. Including the reaction of the HO2/water adduct with NO to yield HNO3 or HOONO into the mechanism is shown to provide a better simulation of the observed water dependence of the radical detector. This reaction would also be important in atmospheric chemistry as it provides an additional loss mechanism for both radicals and NOx

The distribution of nitrogen oxides off the East Coast of North America

Measurements of NO and NOx' (as measured by a chemiluminescent analyzer equipped with a FeSO4 converter) were made from an aircraft off the east coast of North America in January and February 1986. These measurements show the mixing ratios of the nitrogen oxides to be higher than encountered in remote continental or marine environments. Both the free troposphere and boundary layer mixing ratio distributions are skewed to ward high mixing ratios and are best described by a gamma probability distribution. The mean mixing ratios observed were 2.9 parts per billion by volume (ppbv) in the boundary layer and 0.55 ppbv in the free troposphere for NOx', and 0.56 ppbv in the boundary layer and 0.18 in the free troposphere for NO