Instrumentation and Measurement Strategy for the NOAA SENEX Aircraft Campaign as Part of the Southeast Atmosphere Study 2013.

Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeast of the US. In addition, anthropogenic emissions are significant in the Southeast US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions.

Scaling relationship for NO2 pollution and urban population size: a satellite perspective.

Concern is growing about the effects of urbanization on air pollution and health. Nitrogen dioxide (NO2) released primarily from combustion processes, such as traffic, is a short-lived atmospheric pollutant that serves as an air-quality indicator and is itself a health concern. We derive a global distribution of ground-level NO2 concentrations from tropospheric NO2 columns retrieved from the Ozone Monitoring Instrument (OMI). Local scaling factors from a three-dimensional chemistry-transport model (GEOS-Chem) are used to relate the OMI NO2 columns to ground-level concentrations. The OMI-derived surface NO2 data are significantly correlated (r = 0.69) with in situ surface measurements. We examine how the OMI-derived ground-level NO2 concentrations, OMI NO2 columns, and bottom-up NOx emission inventories relate to urban population. Emission hot spots, such as power plants, are excluded to focus on urban relationships. The correlation of surface NO2 with population is significant for the three countries and one continent examined here: United States (r = 0.71), Europe (r = 0.67), China (r = 0.69), and India (r = 0.59). Urban NO2 pollution, like other urban properties, is a power law scaling function of the population size: NO2 concentration increases proportional to population raised to an exponent. The value of the exponent varies by region from 0.36 for India to 0.66 for China, reflecting regional differences in industrial development and per capita emissions. It has been generally established that energy efficiency increases and, therefore, per capita NOx emissions decrease with urban population; here, we show how outdoor ambient NO2 concentrations depend upon urban population in different global regions.

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.

Increasing springtime ozone mixing ratios in the free troposphere over western North America.

In the lowermost layer of the atmosphere-the troposphere-ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA's compliance with its ozone air quality standard.

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.

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.

Exercise testing in special situations: ER, preoperative and disability evaluation.

In a number of medical centers, exercise testing has proven to be a safe and useful tool in the evaluation of patients presenting chest pain in an emergency room. At these centers, after a period of observation without evidence of acute myocardial infarction, exercise testing is done. If the exercise test result is normal, the patient is discharged from the emergency room, without being admitted to the hospital. Exercise testing is a well-accepted noninvasive method to evaluate at-risk patients being considered for elective noncardiac surgery. Exercise testing is frequently used to determine functional capacity during disability assessment.

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.

A watershed-based cumulative risk impact analysis: environmental vulnerability and impact criteria.

Swine Concentrated Animal Feeding Operations (CAFOs) have received much attention in recent years. As a result, a watershed-based screening tool, the Cumulative Risk Index Analysis (CRIA), was developed to assess the cumulative impacts of multiple CAFO facilities in a watershed subunit. The CRIA formula calculates an index number based on: 1) the area of one or more facilities compared to the area of the watershed subunit, 2) the average of the environmental vulnerability criteria, and 3) the average of the industry-specific impact criteria. Each vulnerability or impact criterion is ranked on a 1 to 5 scale, with a low rank indicating low environmental vulnerability or impact and a high rank indicating high environmental vulnerability or impact. The individual criterion ranks, as well as the total CRIA score, can be used to focus the environmental analysis and facilitate discussions with industry, public, and other stakeholders in the Agency decision-making process.

Scientific misconduct and correcting the scientific literature.

Journal editors are among those who must face the issue of when and how to correct the scientific literature when an allegation or finding of scientific misconduct occurs. The author describes an instructive incident of tainted data and a subsequent allegation of misconduct that involved a federally-sponsored study where some data had been fabricated. The journals that had published or were considering articles from that study were not told about the problem for almost four years after the initial allegations of misconduct. The author then provides information to throw light on such questions as: Who has the responsibility to ensure that a manuscript that may contain falsified or fabricated data is not published? Who has the responsibility to correct the literature when falsified or fabricated data have been published, and at what point should that correction be made? For example, should it be when the problem of data is suspected or when it is proven? And if proven, proven by whom? How is the larger scientific community to be notified about the problem? Where and when should the correction or retraction appear, and what should it tell readers about the basis for the retraction or correction? She also presents data from 25 cases to show the various lengths of time involved in correcting the literature after allegations of research misconduct had been made. The author concludes that the record shows how disconnected journal editors have been from the scientific misconduct process and that expectations differ regarding the obligations of authors, research institutions, and federal agencies about informing a journal when an allegation of scientific misconduct is made about a publication in its pages. The 25 cases show that substantial delays in notifying the journal and the public about allegations and findings of scientific misconduct are endemic, and that all parties have far to go in appreciating their roles in maintaining the integrity of the biomedical literature.

Isolation of fecal coliform bacteria from the diamondback terrapin (Malaclemys terrapin centrata).

Total and fecal coliform bacteria were isolated from the cloaca and feces of the estuarine diamondback terrapin. The majority of samples contained fecal coliforms. Escherichia coli was the predominant fecal coliform species isolated, and members of the genus Salmonella were isolated from 2 of 39 terrapins. Fecal coliform numbers are used to regulate shellfish harvests, and diamondback terrapins inhabit the brackish-water habitats where oyster beds are found; therefore, these findings have implications for the efficacy of current regulatory parameters in shellfishing waters.

Usefulness of isometric hand grip exercise in detecting coronary artery disease during dobutamine atropine stress echocardiography in patients with either stable angina pectoris or another type of positive stress test.

Dobutamine atropine stress echocardiography (DASE) detects coronary artery disease (CAD) by increasing myocardial oxygen demand causing ischemia. The sensitivity of the test for detection of CAD is reduced in patients with submaximal stress. We hypothesized that increasing cardiac work load by adding isometric exercise would improve the detection of ischemia during DASE. We studied 31 patients, mean age 57+/-11 years, with angiographically documented CAD. Patients underwent DASE using incremental dobutamine doses from 5 to 40 microg/kg/min, followed by atropine if peak heart rate was <85% of predicted maximal. Hand grip was then performed for 2 minutes at 33% of maximal voluntary contraction, while dobutamine infusion was maintained at the peak dose. The addition of hand grip during dobutamine stress was associated with a significant increase in systolic blood pressure (143+/-21 vs 164+/-24 mm Hg, p = 0.001) and left ventricular end-systolic circumferential wall stress (72+/-30 x 10(3) dynes/cm2 vs 132+/-34 x 10(3) dynes/cm2, p = 0.004). Wall motion score index increased from 1.0 at rest to 1.15+/-0.18 with dobutamine (p = 0.0004 vs rest), and increased further to 1.29+/-0.22 with the addition of hand grip (p = 0.004 vs dobutamine). Ischemia was detected in 19 patients (62%) with dobutamine-atropine stress alone and in 25 (83%) after the addition of hand grip (p <0.05). The addition of hand grip during DASE is feasible, and improves the detection of myocardial ischemia.

Addition of a bone marrow "facilitating cell" population increases stem cell-derived cobblestone area formation in impaired long-term bone marrow culture stroma.

Treatment of mouse bone marrow (BM) with rabbit anti-mouse brain serum (RAMBS) plus complement (C') depletes several cell types, including T cells and facilitating cells (FCs), that is, cells that facilitate engraftment of sorted allogeneic stem cells (SCs) in vivo. In the present study, treatment of BM with RAMBS+C' resulted in the depletion of approximately half of the late cobblestone area (CA)-forming stem cells as assayed on irradiated long-term bone marrow culture (LTBMC) stroma. In addition, LTBMC of RAMBS+C'-treated BM produced functionally impaired stroma with reduced ability to support CA formation by nontreated exogenous SCs. This stromal impairment was not due to depletion of TCRalphabeta T cells in the BM, because BM cultures from TCR alpha-chain knockout mice supported normal numbers of exogenous CAs. Because CD8+/TCR- cells are enriched for FCs, we tested the effect of adding these cells back to the treated BM prior to culture. The sorted FCs alone did not produce CAs, but did improve the ability of the impaired stroma to support late CA formation by sorted SCs. These studies provide a new model for dissecting the roles of different cellular components of BM in producing functional stroma that supports CA formation by SCs, and show that the number of CAs formed depends on the "quality" of the stroma as well as the number of SCs seeded. These findings further suggest that CD8+/TCR- BM cells may be important for the establishment of functional stroma.

Improving the scientific misconduct hearing process.

The overturning and withdrawal of several of the Office of Research Integrity's (ORI's) findings of scientific misconduct have called its role into question. The contested findings of scientific misconduct that have been tried before the hearing body have been based on lengthy and expensive ORI investigations. How could ORI have failed to prove its findings of scientific misconduct after the commitment of substantial resources that far exceed those devoted during institutional investigations? One reason may be that the current hearing process makes it difficult or impossible for ORI, institutions, or individuals to prove scientific misconduct. The hearing process has been criticized by discouraged whistleblowers who believe that their allegations of scientific misconduct should have been upheld, and by the accused for the expensive and protracted nature of the proceedings. The following article examines problems in the scientific misconduct hearing process and suggests that the process could be improved by letting administrative law judges, patent attorneys, and a scientific majority decide these cases.

Activation of CGS 12094 (prinomide metabolite) to 1,4-benzoquinone by myeloperoxidase: implications for human idiosyncratic agranulocytosis.

Many marketed pharmaceuticals are known to cause idiosyncratic agranulocytosis in humans. Similarly prinomide, an antiinflammatory drug, was associated with a low incidence of agranulocytosis (<0.3%) in clinical trials, even though chronic toxicity studies in rodents and primates showed no evidence of agranulocytosis with either prinomide or its parahydroxy metabolite, CGS 12094. To investigate mechanisms for this human specific toxicity, experiments were conducted to study the metabolism of prinomide and CGS 12094 by myeloperoxidase (MPO), a major enzyme of neutrophils and leukocyte progenitor cells. Although prinomide was not metabolized by human MPO, CGS 12094 was rapidly metabolized (>90%; 2 min); this reaction was dependent on H2O2 and MPO and was inhibited by azide. During the MPO-catalyzed metabolism of CGS 12094, reactive intermediates that irreversibly bound to protein and cysteine were generated. One of the reactive metabolites generated was identified by mass spectroscopy and trapping with cysteine as 1,4-benzoquinone, a compound implicated in the myelotoxicity associated with benzene. Thus during conditions which lead to elevated levels of H2O2 (e.g., active inflammation), CGS 12094 is rapidly metabolized by MPO to reactive intermediates that may be related to prinomide-induced agranulocytosis.

A processive versus a distributive mechanism of action correlates with differences in ability of normal and xeroderma pigmentosum group A endonucleases to incise damaged nucleosomal DNA.

A DNA endonuclease, isolated from the nuclei of normal human and xeroderma pigmentosum complementation group A (XPA) cells, which recognizes predominately pyrimidine dimers, was examined for the mechanism by which it locates sites of damage on UVC-irradiated DNA. In reaction mixtures with low ionic strengths (i.e. lacking KCl), the normal and XPA endonuclease locate sites of UV damage on both naked and reconstituted nucleosomal DNA by different mechanisms. On both of these substrates, the normal endonuclease acts by a processive mechanism, meaning that it binds non-specifically to DNA and scans the DNA for sites of damage, whereas the XPA endonuclease acts by a distributive one, meaning that it randomly locates sites of damage on DNA. However, while both the normal and XPA endonucleases can incise UVC irradiated naked DNA, they differ in ability to incise damaged nucleosomal DNA. The normal endonuclease showed increased activity on UVC treated nucleosomal DNA compared with naked DNA, whereas the XPA endonuclease showed decreased activity on the damaged nucleosomal substrate. Since a processive mechanism of action is sensitive to the ionic strength of the micro-environment, the KCl concentration of the reaction was increased. At 70 mM KCI, the normal endonuclease switched to a distributive mechanism of action and its ability to incise damaged nucleosomal DNA also decreased. These studies show that there is a correlation between the ability of these endonucleases to act by a processive mechanism and their ability to incise damaged nucleosomal DNA; the normal endonuclease, which acts processively, can incise damaged nucleosomal DNA, whereas the XPA endonuclease, which acts distributively, is defective in ability to incise this substrate.

Correction of the DNA repair defect in Fanconi anemia complementation groups A and D cells.

We have previously isolated from Fanconi anemia, complementation groups A (FA-A) and D (FA-D) cells, a DNA endonuclease complex which is defective in its ability to incise DNA containing interstrand cross-links produced by psoralen plus UVA light. The repair capabilities of the FA complexes, compared with those of the corresponding normal complex, have now been examined using two types of complementation analysis. First, introduction of the normal complex, by electroporation, into 8-methoxypsoralen (8-MOP) plus UVA treated FA-A and FA-D cells resulted in correction of their repair defect, determined by measuring repair-related unscheduled DNA synthesis (UDS). The FA-A and FA-D complexes could similarly complement the repair defect in each others' cells, but not in their own. Second, mixing the normal with the FA-A and FA-D complexes, or the FA-A with the FA-D complex, in a cell-free system resulted in correction of the defect in ability of these FA complexes to incise damaged DNA. These results indicate that the normal complex contains the proteins needed to correct the DNA repair defect in FA-A and FA-D cells and that the FA-A and FA-D complexes contain the protein needed to complement the repair defect in each other.