39 research outputs found
Recommended from our members
A new interpretation of total column BrO during Arctic spring
Emission of bromine from sea-salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal of surface ozone during Arctic spring. Regions of enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements of BrO and O3 within the convective boundary layer (CBL) during the ARCTAS and ARCPAC field campaigns at times bear little relation to enhanced column BrO. We show that the locations of numerous satellite BrO "hotspots" during Arctic spring are consistent with observations of total column ozone and tropopause height, suggesting a stratospheric origin to these regions of elevated BrO. Tropospheric enhancements of BrO large enough to affect the column abundance are also observed, with important contributions originating from above the CBL. Closure of the budget for total column BrO, albeit with significant uncertainty, is achieved by summing observed tropospheric partial columns with calculated stratospheric partial columns provided that natural, short-lived biogenic bromocarbons supply between 5 and 10 ppt of bromine to the Arctic lowermost stratosphere. Proper understanding of bromine and its effects on atmospheric composition requires accurate treatment of geographic variations in column BrO originating from both the stratosphere and troposphere. Copyright 2010 by the American Geophysical Union
Genetic variation in HSD17B13 reduces the risk of developing cirrhosis and hepatocellular carcinoma in alcohol misusers
BACKGROUND & AIMS: Carriage of rs738409:G in patatin-like phospholipase domain-containing 3 (PNPLA3) is associated with an increased risk for developing alcohol-related cirrhosis and hepatocellular carcinoma (HCC). Recently, rs72613567:TA in hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) was shown to be associated with a reduced risk for developing alcohol-related liver disease and to attenuate the risk associated with PNPLA3 rs738409:G. This study explores the risk-associations between these two genetic variants and the development of alcohol-related cirrhosis and HCC. APPROACH AND RESULTS: Variants in HSD17B13 and PNPLA3 were genotyped in 6,171 participants, including: 1,031 with alcohol-related cirrhosis and HCC; 1,653 with alcohol-related cirrhosis without HCC; 2,588 alcohol misusers with no liver disease; and 899 healthy controls. Genetic associations with the risks for alcohol-related cirrhosis and HCC were determined using logistic regression analysis. Carriage of HSD17B13 rs72613567:TA was associated with a lower risk for both cirrhosis (OR 0.79 [95% CI 0.72-0.88], p=8.13×10-6) and HCC (OR 0.77 [95% CI 0.68-0.89], p=2.27×10-4), while carriage of PNPLA3 rs738409:G was associated with an increased risk for developing cirrhosis (OR 1.70 [95% CI 1.54-1.88], p=1.52x10-26) and HCC (OR 1.77 [95% CI 1.58-1.98], p=2.31×10-23). These associations remained significant after adjusting for age, sex, body mass index, type II diabetes mellitus and country. Carriage of HSD17B13 rs72613567:TA attenuated the risk for developing cirrhosis associated with PNPLA3 rs738409:G in both men and women but the protective effect against the subsequent development of HCC was only observed in men (p=1.72×10-4; ORallelic, 0.75; 95% CI, 0.64-0.87). CONCLUSIONS: Carriage of variants in PNPLA3 and HSD17B13 differentially affect the risk for developing advanced alcohol-related liver disease. A genotypic/phenotypic risk score might facilitate earlier diagnosis of HCC in this population
Recommended from our members
Influence of Ohio Valley emissions on fine particle sulfate measured from aircraft over large regions of the Eastern U.S. and Canada during INTEX-NA
Aircraft measurements of fine inorganic aerosol composition were made with a
particle-into-liquid sampler coupled to dual ion chromatographs (PILS-IC) as part of
the NASA INTEX-NA study. The sampling campaign, which lasted from 1 July to
14 August 2004, centered over the eastern United States and Canada and showed that
sulfate was the dominant inorganic species measured. The highest sulfate concentrations
were observed at altitudes below 2 km, and back trajectory analyses showed a
distinct difference between air masses that had or had not intercepted the Ohio River
valley (ORV) region. Air masses encountered below 2 km with a history over the ORV
had sulfate concentrations that were higher by a factor of 3.2 and total sulfur (S)
concentrations higher by 2.5. The study’s highest sulfate concentrations were found in
these air masses. The sulfur of the ORV air masses was also more processed with a mean
sulfate to total sulfur molar ratio of 0.5 compared to 0.3 in non-ORV measurements.
Results from a second, independent trajectory model agreed well with those from the
primary analysis. These ORV-influenced air masses were encountered on multiple days
and were widely spread across the eastern United States and western Atlantic region
Recommended from our members
Influence of Ohio Valley emissions on fine particle sulfate measured from aircraft over large regions of the Eastern U.S. and Canada during INTEX-NA
Aircraft measurements of fine inorganic aerosol composition were made with a
particle-into-liquid sampler coupled to dual ion chromatographs (PILS-IC) as part of
the NASA INTEX-NA study. The sampling campaign, which lasted from 1 July to
14 August 2004, centered over the eastern United States and Canada and showed that
sulfate was the dominant inorganic species measured. The highest sulfate concentrations
were observed at altitudes below 2 km, and back trajectory analyses showed a
distinct difference between air masses that had or had not intercepted the Ohio River
valley (ORV) region. Air masses encountered below 2 km with a history over the ORV
had sulfate concentrations that were higher by a factor of 3.2 and total sulfur (S)
concentrations higher by 2.5. The study’s highest sulfate concentrations were found in
these air masses. The sulfur of the ORV air masses was also more processed with a mean
sulfate to total sulfur molar ratio of 0.5 compared to 0.3 in non-ORV measurements.
Results from a second, independent trajectory model agreed well with those from the
primary analysis. These ORV-influenced air masses were encountered on multiple days
and were widely spread across the eastern United States and western Atlantic region
Recommended from our members
Measurement of HO2NO2 in the free troposphere during the Intercontinental Chemical Transport Experiment - North America 2004
The first direct in situ measurements of HO2NO2 in the upper troposphere were performed from the NASA DC-8 during the Intercontinental Chemical Transport Experiment-North America 2004 with a chemical ionization mass spectrometer (CIMS). These measurements provide an independent diagnostic of HOx chemistry in the free troposphere and complement direct observations of HOx, because of the dual dependency of HO2NO2 on HOx and NOx. On average, the highest HO2NO2 mixing ratio of 76 pptv (median = 77 pptv, σ, = 39 pptv) was observed at altitudes of 8-9 km. Simple steady state calculations of HO2NO2, constrained by measurements of HOx, NOx, and J values, are in good agreement (slope = 0.90, R2 = 0.60, and z = 5.5-7.5 km) with measurements in the midtroposphere where thermal decomposition is the major loss process. Above 8 km the calculated steady state HO2NO2 is in poor agreement with observed values (R2 = 0.20) and is typically larger by a factor of 2.4. Conversely, steady state calculations using model-derived HOx show reasonable agreement with the observed HO2NO2 in both the midtroposphere (slope = 0.96, intercept = 7.0, and R2 = 0.63) and upper troposphere (slope = 0.80, intercept = 32.2, and R2 = 0.58). These results indicate that observed HO2 and HO2NO2 are in poor agreement in the upper troposphere but that HO2NO2 levels are consistent with current photochemical theory. Copyright 2007 by the American Geophysical Union
Recommended from our members
Measurement of HO2NO2 in the free troposphere during the Intercontinental Chemical Transport Experiment - North America 2004
The first direct in situ measurements of HO2NO2 in the upper troposphere were performed from the NASA DC-8 during the Intercontinental Chemical Transport Experiment-North America 2004 with a chemical ionization mass spectrometer (CIMS). These measurements provide an independent diagnostic of HOx chemistry in the free troposphere and complement direct observations of HOx, because of the dual dependency of HO2NO2 on HOx and NOx. On average, the highest HO2NO2 mixing ratio of 76 pptv (median = 77 pptv, σ, = 39 pptv) was observed at altitudes of 8-9 km. Simple steady state calculations of HO2NO2, constrained by measurements of HOx, NOx, and J values, are in good agreement (slope = 0.90, R2 = 0.60, and z = 5.5-7.5 km) with measurements in the midtroposphere where thermal decomposition is the major loss process. Above 8 km the calculated steady state HO2NO2 is in poor agreement with observed values (R2 = 0.20) and is typically larger by a factor of 2.4. Conversely, steady state calculations using model-derived HOx show reasonable agreement with the observed HO2NO2 in both the midtroposphere (slope = 0.96, intercept = 7.0, and R2 = 0.63) and upper troposphere (slope = 0.80, intercept = 32.2, and R2 = 0.58). These results indicate that observed HO2 and HO2NO2 are in poor agreement in the upper troposphere but that HO2NO2 levels are consistent with current photochemical theory. Copyright 2007 by the American Geophysical Union