Mass spectral analysis of organic aerosol formed downwind of the Deepwater Horizon oil spill: field studies and laboratory confirmations.

In June 2010, the NOAA WP-3D aircraft conducted two survey flights around the Deepwater Horizon (DWH) oil spill. The Gulf oil spill resulted in an isolated source of secondary organic aerosol (SOA) precursors in a relatively clean environment. Measurements of aerosol composition and volatile organic species (VOCs) indicated formation of SOA from intermediate-volatility organic compounds (IVOCs) downwind of the oil spill (Science2011, 331, doi 10.1126/science.1200320). In an effort to better understand formation of SOA in this environment, we present mass spectral characteristics of SOA in the Gulf and of SOA formed in the laboratory from evaporated light crude oil. Compared to urban primary organic aerosol, high-mass-resolution analysis of the background-subtracted SOA spectra in the Gulf (for short, "Gulf SOA") showed higher contribution of C(x)H(y)O(+) relative to C(x)H(y)(+) fragments at the same nominal mass. In each transect downwind of the DWH spill site, a gradient in the degree of oxidation of the Gulf SOA was observed: more oxidized SOA (oxygen/carbon = O/C ∼0.4) was observed in the area impacted by fresher oil; less oxidized SOA (O/C ∼0.3), with contribution from fragments with a hydrocarbon backbone, was found in a broader region of more-aged surface oil. Furthermore, in the plumes originating from the more-aged oil, contribution of oxygenated fragments to SOA decreased with downwind distance. Despite differences between experimental conditions in the laboratory and the ambient environment, mass spectra of SOA formed from gas-phase oxidation of crude oil by OH radicals in a smog chamber and a flow tube reactor strongly resembled the mass spectra of Gulf SOA (r(2) > 0.94). Processes that led to the observed Gulf SOA characteristics are also likely to occur in polluted regions where VOCs and IVOCs are coemitted.

Organic aerosol formation downwind from the Deepwater Horizon oil spill.

A large fraction of atmospheric aerosols are derived from organic compounds with various volatilities. A National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft made airborne measurements of the gaseous and aerosol composition of air over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico that occurred from April to August 2010. A narrow plume of hydrocarbons was observed downwind of DWH that is attributed to the evaporation of fresh oil on the sea surface. A much wider plume with high concentrations of organic aerosol (>25 micrograms per cubic meter) was attributed to the formation of secondary organic aerosol (SOA) from unmeasured, less volatile hydrocarbons that were emitted from a wider area around DWH. These observations provide direct and compelling evidence for the importance of formation of SOA from less volatile hydrocarbons.

Airborne measurements of ethene from industrial sources using laser photo-acoustic spectroscopy.

A laser photoacoustic spectroscopy (LPAS) instrument was developed and used for aircraft measurements of ethene from industrial sources near Houston, Texas. The instrument provided 20 s measurements with a detection limit of less than 0.7 ppbv. Data from this instrument and from the GC-FID analysis of air samples collected in flight agreed within 15% on average. Ethene fluxes from the Mt. Belvieu chemical complex to the northeast of Houston were quantified during 10 different flights. The average flux was 520 +/- 140 kg h(-1) in agreement with independent results from solar occultation flux (SOF) measurements, and roughly an order of magnitude higher than regulatory emission inventories indicate. This study shows that ethene emissions are routinely at levels that qualify as emission upsets, which need to be reported to regional air quality managers.

Large-scale purification of human BACE expressed in mammalian cells and removal of the prosegment with HIV-1 protease to improve crystal diffraction.

BACE, or beta-secretase, is an attractive target in the treatment of Alzheimer's Disease because of its involvement in the generation of amyloid beta peptides. BACE is a type I transmembrane aspartyl protease composed of pre-, pro-, catalytic, transmembrane and cytoplasmic domains. For the present study, the coding sequence was truncated just before the transmembrane domain and the resulting construct was extended with the C-terminal addition of a (His)(6) and expressed in several mammalian host cells. The enzyme expressed in CHO cells had the best crystallographic behavior and was purified in large quantities in a three step procedure. The purified BACE was comprised of two forms, namely the full length proBACE construct beginning with Thr(1), and a derivative missing the first 24 amino acids beginning with E(25). These BACE precursors co-crystallized in the presence of inhibitors yielding structures to 3.2 A resolution. HIV-1 protease treatment of this mixture resulted in complete cleavage of the F(39)-V(40) bond, leaving the V(40)EM...ES(432) (His)(6) derivative that was purified yielding an enzyme that was no more active than untreated BACE but co-crystallized with inhibitors producing well shaped, bipyramidal co-crystals diffracting to 2.6 A resolution.

Fossil-fueled power plants as a source of atmospheric carbon monoxide.

Elevated carbon monoxide (CO) mixing ratios in excess of those derived from emissions inventories have been observed in plumes from one gas- and coal-fired power plant and three of four lignite coal-fired electric utility power plants observed in east and central Texas. Observations of elevated CO on days characterized by differing wind directions show that CO emissions from the lignite plants were relatively constant over time and cannot be ascribed to separate sources adjacent to the power plants. These three plants were found to be emitting CO at rates 22 to 34 times those tabulated in State and Federal emissions inventories. Elevated CO emissions from the gas- and coal-fired plant were highly variable on time scales of hours to days, in one case changing by a factor of 8 within an hour. Three other fossil-fueled power plants, including one lignite-fired plant observed during this study, did not emit substantial amounts of CO, suggesting that a combination of plant operating conditions and the use of lignite coal may contribute to the enhanced emissions. Observed elevated CO emissions from the three lignite plants, if representative of average operating conditions, represent an additional 30% of the annual total CO emissions from point sources for the state of Texas.

Observations of ozone formation in power plant plumes and implications for ozone control strategies.

Data taken in aircraft transects of emissions plumes from rural U.S. coal-fired power plants were used to confirm and quantify the nonlinear dependence of tropospheric ozone formation on plume NO(x) (NO plus NO(2)) concentration, which is determined by plant NO(x) emission rate and atmospheric dispersion. The ambient availability of reactive volatile organic compounds, principally biogenic isoprene, was also found to modulate ozone production rate and yield in these rural plumes. Differences of a factor of 2 or greater in plume ozone formation rates and yields as a function of NO(x) and volatile organic compound concentrations were consistently observed. These large differences suggest that consideration of power plant NO(x) emission rates and geographic locations in current and future U.S. ozone control strategies could substantially enhance the efficacy of NO(x) reductions from these sources.

Foster and adoptive mothers' assessment of permanent family placements.

OBJECTIVES: To obtain the new carers' evaluation of the success of permanent placement of children within their families and any special needs in the children, and to determine the adequacy of support after placement. DESIGN: A postal questionnaire was sent to the foster or adoptive mothers of a five year cohort of 234 children placed for permanence, three to eight years previously, by one local authority. SETTING: Newcastle upon Tyne Social Services Adoption and Fostering Unit. SUBJECTS: All 234 permanent family placements recommended by the family placement panel from 1 January 1986 to 31 December 1990. MAIN OUTCOME MEASURE: The adoptive or foster mothers' evaluation of the placement. RESULTS: There was a 54% response rate, but the respondents did not differ significantly from the non-respondents in the variables tested. Only 33% of the children were placed when less than 2 years old with no special needs. Twenty per cent of the school age children had statements of special educational needs at placement. Ninety seven per cent of infant placements were rated "very successful' for the child by the new mothers, as were 90% of 1-6 year olds, but only 31% of children who were placed when older than 6 years were rated in this way. A third of the adoptive and foster mothers had experienced major difficulties in the placement and six carers said that more medical/psychiatric input would have prevented breakdown. CONCLUSION: There is a role for health care professionals to provide ongoing support, especially for older children with special needs.

Outcome in placements for adoption or long-term fostering.

OBJECTIVES: To describe a five year cohort of children whose placements for adoption or long-term (permanent) fostering were recommended by Newcastle upon Tyne Family Placement Panel and to determine the outcome of these placements. DESIGN: Retrospective total five year cohort study. Outcome data were extracted from records three to five years after placement. SETTING: Newcastle upon Tyne Social Services Adoption and Fostering Unit. SUBJECTS: All 234 permanent family placements recommended by the Family Placement Panel from 1 January 1986 to 31 December 1990. MAIN OUTCOME MEASURE: Disruption of the placement. RESULTS: A total of 20% of the placements had disrupted (2% of adoptive placements and 51% of long-term fostering placements). Disruption was generally associated with increased age at placement. Disruption was not associated with special needs, the sex of the child, previous disruption, or being placed with siblings. Forty four percent of children from disrupted placements returned to live with their birth families. CONCLUSION: In view of the poor outcome for older children, there is a case for more preventative work and also for more support after placement.

Export of north american ozone pollution to the north atlantic ocean.

Measurement of the levels of ozone and carbon monoxide (a tracer of anthropogenic pollution) at three surface sites on the Atlantic coast of Canada allow the estimation of the amount of ozone photochemically produced from anthropogenic precursors over North America and transported to the lower troposphere over the temperate North Atlantic Ocean. This amount is greater than that injected from the stratosphere, the primary natural source of ozone. This conclusion supports the contention that ozone derived from anthropogenic pollution has a hemisphere-wide effect at northern temperate latitudes.

Increase in cerebral palsy in normal birthweight babies.

A register has been compiled of the 421 children with congenital cerebral palsy born between 1960 and 1975 from a defined geographical area of North East England (population 770 000). There was a fall in the rate of cerebral palsy among very low birthweight babies between 1964 and 1975 and also in the small group with dyskinetic cerebral palsy. The rate rose, however, among babies weighing more than 2.5 kg at birth in the second half of the study, in parallel with changes in perinatal mortality. The net effect is that the overall congenital cerebral palsy rate (mean 1.64 per 1000 livebirths) showed a gradual rise between 1968 and 1975. This conclusion is reinforced by evidence of a rise in incidence among the subgroup of patients with severe cerebral palsy (as defined by an interval measurement of handicap) during the same period.