Rapid transport of East Asian pollution to the deep tropics

Abstract. Anthropogenic emissions from East Asia have increased over recent decades, and under the prevailing westerly winds, these increases have led to changes in atmospheric composition as far afield as North America. Here we show that, during Northern Hemisphere (NH) winter, pollution originating in East Asia also directly affects atmospheric composition in the deep tropics. We present observations of marked intra-seasonal variability in the anthropogenic tracer perchloroethene (C2Cl4) collected at two locations in Borneo during the NH winter of 2008/09. We use the NAME trajectory model to show that the observed enhancements in C2Cl4 mixing ratio are caused by rapid meridional transport, in the form of "cold surges", from the relatively polluted East Asian land mass. In these events air masses can move across > 30° of latitude in 4 days. We then present data from the Monitoring Atmospheric Composition and Climate reanalysis which suggests that air masses high in C2Cl4 may also contain levels of the pollutants carbon monoxide and ozone that are approximately double the typical "background" levels in Borneo. Convection in Southeast Asia can be enhanced by cold surges, and further trajectory calculations indicate that the polluted air masses can subsequently be lifted to the tropical upper troposphere. This suggests a potentially important connection between mid-latitude pollution sources and the very low stratosphere. This work was supported by a NERC consortium grant to the OP3 team, by NCAS, by the European Commission through the SCOUT-O3 project (505390-GOCECF2004), though the ERC ACCI project, Project No 267760, and by NERC western Pacific grant number NE/F020341/1 and NERC CAST grant number NE/J006246/1. M. J. Ashfold thanks NERC for a research studentship. A. D. Robinson acknowledges NERC for their support through small grant project NE/D008085/1. N. R. P. Harris is supported by a NERC Advanced Research Fellowship. We thank the Sabah Foundation, Danum Valley Field Centre and the Royal Society (Glen Reynolds) for field site support. This is paper number X of the Royal Society’s South East Asian Rainforest Research Programme. We are grateful for use of data provided by the MACC-II project, funded by the European Union under the 7th Framework Programme. We also acknowledge use of the NAME atmospheric dispersion model and associated NWP meteorological data sets made available to us by the Met O ce. We acknowledge the significant storage resources and analysis facilities made available to us on JASMIN by STFC CEDA along with the corresponding support teams.This is the published version. It first appeared at: http://www.atmos-chem-phys-discuss.net/14/30705/2014/acpd-14-30705-2014.html

Determination of chlorinated solvents in industrial water and wastewater by DAI–GC–ECD

A very simple and quick analytical method, based on direct aqueous injection, for determination of halogenated solvents in refinery water and wastewater, is described. There is a need to determine halogenated solvents in refinery water streams, because they may originate from several processes. There is also a need to develop methods enabling VOX to be determined in samples containing oil fractions. The method described enables simultaneous determination of 26 compounds with low detection limits (sub-μg L−1) and excellent precision, especially for highly halogenated solvents. The matrix effects of four types of sample were evaluated—the method seemed to be relatively insensitive to variations in matrix composition. Deuterated 1,2-dichloroethane was used as internal standard and surrogate compound in quantitative analysis; application of isotopically labelled compounds is rarely reported when non-mass spectrometric detectors are used for analysis. Analysis of real samples showed that the most frequently detected compounds were dichloromethane and 1,2-dichloroethane

Long-term halocarbon observations from a coastal and an inland site in Sabah, Malaysian Borneo

Abstract. Short-lived halocarbons are believed to have important sources in the tropics, where rapid vertical transport could provide a significant source to the stratosphere. In this study, quasi-continuous measurements of short-lived halocarbons are reported for two tropical sites in Sabah (Malaysian Borneo), one coastal and one inland (rainforest). We present the observations for C2Cl4, CHBr3, CH2Br2* (actually ~80% CH2Br2 and ~20% CHBrCl2) and CH3I from November 2008 to January 2010 made using our μDirac gas chromatographs with electron capture detection (GC-ECD). We focus on the first 15 months of observations, showing over one annual cycle for each compound and therefore adding significantly to the few limited-duration observational studies that have been conducted thus far in southeast Asia. The main feature in the C2Cl4 behaviour at both sites is its annual cycle, with the winter months being influenced by northerly flow with higher concentrations, typical of the Northern Hemisphere, and with the summer months influenced by southerly flow and lower concentrations representative of the Southern Hemisphere. No such clear annual cycle is seen for CHBr3, CH2Br2* or CH3I. The baseline values for CHBr3 and CH2Br2* are similar at the coastal (overall median: CHBr3 1.7 ppt, CH2Br2* 1.4 ppt) and inland sites (CHBr3 1.6 ppt, CH2Br2* 1.1 ppt), but periods with elevated values are seen at the coast (overall 95th percentile: CHBr3 4.4 ppt, CH2Br2ast 1.9 ppt), presumably resulting from the stronger influence of coastal emissions. Overall median bromine values from [CHBr3 × 3] + [CH2Br2* × 2] are 8.0 ppt at the coast and 6.8 ppt inland. The median values reported here are largely consistent with other limited tropical data and imply that southeast Asia generally is not, as has been suggested, a hot spot for emissions of these compounds. These baseline values are consistent with the most recent emissions found for southeast Asia using the p-TOMCAT (Toulouse Off-line Model of Chemistry And Transport) model. CH3I, which is only observed at the coastal site, is the shortest-lived compound measured in this study, and the observed atmospheric variations reflect this, with high variability throughout the study period. This work was supported by a NERC consortium grant to the OP3 team, by NCAS, by the European Commission through the SCOUT-O3 project (505390-GOCE-CF2004) and by NERC western Pacific grant number NE/F020341/1 and NERC CAST grant number NE/J006246/1. L. M. O’Brien and M. J. Ashfold thank NERC for research studentships. A. D. Robinson acknowledges NERC for their support through small grant project NE/D008085/1. N. R. P. Harris is supported by a NERC Advanced Research Fellowship. We thank the Sabah Foundation, Danum Valley Field Centre and the Royal Society (Glen Reynolds) for field site support. The research leading to these results has received funding from the European Union’s Seventh Framework Programme FP7/2007–2013 under grant agreement no. 226224 – SHIVA. We thank David Oram and Stephen Humphrey at UEA for their assistance in checking the calibration of our Aculife cylinder in May 2009. This is paper number 626 of the Royal Society’s South East Asian Rainforest Research Programme.This is the final published version. It first appeared at http://www.atmos-chem-phys.net/14/8369/2014/acp-14-8369-2014.html

Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling

Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH$_{4}$mixing ratios measured by the different platforms. To address uncertainty about where CH$_{4}$ emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH$_{4}$ emission areas. We found small differences between the CH$_{4}$ mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH$_{4}$ fluxes. The CH$_{4}$ flux during the campaign was small, with an upper limit of 2.5 nmol m$^{-2}$ s$^{-1}$ in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH$_{4}$ fluxes from the Svalbard continental platform below 0.2 Tg yr$^{-1}$. All estimates are in the lower range of values previously reported.MOCA—Methane Emissions from the Arctic OCean to the Atmosphere: Present and Future Climate Effects is funded by the Research Council of Norway, grant 225814. CAGE—Centre for Arctic Gas Hydrate, Environment and Climate research work was supported by the Research Council of Norway through its Centres of Excellence funding scheme grant 223259. eSTICC—eScience Tools for Investigating Climate Change in northern high latitudes is supported by Nordforsk as Nordic Center of Excellence grant 57001. NERC grants NE/I029293/1 (PI. H. Coe) and NE/I02916/1 (PI J. Pyle) and Methane & Other Greenhouse Gases in the Arctic—Measurements, Process Studies and Modelling (MAMM). The ERC through the ACCI project, project number 267760. The biogenic methane emission data from the LPX-Bern v1.2 model were provided by Renato Spahni. The methane emission data from the GAINS model were provided by IIASA. GFED data are available from http://www.globalfiredata.org/index.html. Airborne data were obtained using the BAe-146-301 Atmospheric Research Aircraft (ARA) flown by Directflight Ltd. and managed by the Facility for Airborne Atmospheric Measurements (FAAM), which is a joint entity of the Natural Environment Research Council (NERC) and the Met Office. Zeppelin and Helmer Hansen atmospheric measurement data are archived in EBAS (http://ebas.nilu.no/) for long-term preservation, access and use. All Zeppelin data for 2014: http://ebas.nilu.no/DataSets.aspx?stations=NO0042G&fromDate=2014-01-01&toDate=2014-12-31. All atmospheric data from RV Helmer Hanssen: http://ebas.nilu.no/DataSets.aspx?stations=NO1000R&fromDate=2014-01-01&toDate=2014-12-31 (password is required until the end of 2017)

Bromocarbons in the tropical coastal and open ocean atmosphere during the 2009 Prime Expedition Scientific Cruise (PESC-09)

Abstract. Atmospheric concentrations of very short-lived species (VSLS) bromocarbons, including CHBr3, CH2Br2, CHCl2Br, CHClBr2, and CH2BrCl, were measured in the Strait of Malacca and the South China and Sulu–Sulawesi seas during a two-month research cruise in June–July 2009. The highest bromocarbon concentrations were found in the Strait of Malacca, with smaller enhancements in coastal regions of northern Borneo. CHBr3 was the most abundant bromocarbon, ranging from 5.2 pmol mol−1 in the Strait of Malacca to 0.94 pmol mol−1 over the open ocean. Other bromocarbons showed lower concentrations, in the range of 0.8–1.3 pmol mol−1 for CH2Br2, 0.1–0.5 pmol mol−1 for CHCl2Br, and 0.1–0.4 pmol mol−1 for CHClBr2. There was no significant correlation between bromocarbons and in situ chlorophyll a, but positive correlations with both MODIS and SeaWiFS satellite chlorophyll a. Together, the short-lived bromocarbons contribute an average of 8.9 pmol mol−1 (range 5.2–21.4 pmol mol−1) to tropospheric bromine loading, which is similar to that found in previous studies from global sampling networks (Montzka et al., 2011). Statistical tests showed strong Spearman correlations between brominated compounds, suggesting a common source. Log–log plots of CHBr3/CH2Br2 versus CHBr2Cl/CH2Br2 show that both chemical reactions and dilution into the background atmosphere contribute to the composition of these halocarbons at each sampling point. We have used the correlation to make a crude estimate of the regional emissions of CHBr3 and to derive a value of 32 Gg yr−1 for the Southeast (SE) Asian region (10° N–20° S, 90–150° E). Finally, we note that satellite-derived chlorophyll a (chl a) products do not always agree well with in situ measurements, particularly in coastal regions of high turbidity, meaning that satellite chl a may not always be a good proxy for marine productivity. We would like to thank MOSTI (Malaysian Ministry of Science, Technology and Innovation). for giving opportunities and financial support for the University of Malaya (UM) and Universiti Kebangsaan Malaysia to participate in this scientific cruise, and other Malaysian public universities and agencies who helped during sampling. The Malaysian Royal Navy is thanked for their help and assistance in all aspects of the cruise. We also thank the SHIVA European FP7 project (grant 226224), NERC, NERC-NCAS and the British Council, through a PMI2 grant, for their support. Neil Harris would like to thank NERC for his Research Fellowship; Emma Leedham and Matt Ashfold thank NERC for studentships, and Doreena Dominick, Lin Chin Yik, Fatimah Ahamad and Nur Ily Hamizah for their assistance and the Ministry of Higher Education Malaysia (KPT’s) ERGS grant ER025-2013A. Finally, we also would like to thank Universiti Kebangsaan Malaysia (UKM) for the ICONIC-2013-004 grant, MOSTI e-science grant 04-01-02-SF-0752 for Universiti Kebangsaan Malaysia (UKM), UKM GGPM-2013-080 and UKM DPP-2014-162 and GUP-2013-057 for financial support.This paper was originally published in Atmospheric Chemistry and Physics, 14, 8137-8148, doi:10.5194/acp-14-8137-2014, 201

The persistence of epiphyseal scars in the distal radius in adult individuals

The use of radiographic imaging in the estimation of chronological age facilitates the analysis of structures not visible on gross morphological inspection. Following the completion of epiphyseal fusion, a thin radio-opaque band, the epiphyseal scar, may be observed at the locus of the former growth plate. The obliteration of this feature has previously been interpreted as the final stage of skeletal maturation and consequently has been included as a criterion in several methods of age estimation, particularly from the distal radius. Due to the recommendations relating to age estimation in living individuals, accurate assessment of age from the distal radius is of great importance in human identification; however, the validity of the interpretation of the obliteration of the epiphyseal scar as an age-related process has not been tested. A study was undertaken to assess the persistence of epiphyseal scars in adults between 20 and 50 years of age through the assessment of 616 radiographs of left and right distal radii from a cross-sectional population. This study found that 86 % of females and 78 % of males retained some remnant of the epiphyseal scar in the distal radius. The relationships between chronological age, biological sex and the persistence of the epiphyseal scar were not statistically significant. The findings of this study indicate that the epiphyseal scars may persist in adult individuals until at least 50 years of age. No maximum age should therefore be applied to the persistence of an epiphyseal scar in the distal radius

Circulating Pneumolysin Is a Potent Inducer of Cardiac Injury during Pneumococcal Infection

Streptococcus pneumoniae accounts for more deaths worldwide than any other single pathogen through diverse disease manifestations including pneumonia, sepsis and meningitis. Life-threatening acute cardiac complications are more common in pneumococcal infection compared to other bacterial infections. Distinctively, these arise despite effective antibiotic therapy. Here, we describe a novel mechanism of myocardial injury, which is triggered and sustained by circulating pneumolysin (PLY). Using a mouse model of invasive pneumococcal disease (IPD), we demonstrate that wild type PLY-expressing pneumococci but not PLY-deficient mutants induced elevation of circulating cardiac troponins (cTns), well-recognized biomarkers of cardiac injury. Furthermore, elevated cTn levels linearly correlated with pneumococcal blood counts (r=0.688, p=0.001) and levels were significantly higher in non-surviving than in surviving mice. These cTn levels were significantly reduced by administration of PLY-sequestering liposomes. Intravenous injection of purified PLY, but not a non-pore forming mutant (PdB), induced substantial increase in cardiac troponins to suggest that the pore-forming activity of circulating PLY is essential for myocardial injury in vivo. Purified PLY and PLY-expressing pneumococci also caused myocardial inflammatory changes but apoptosis was not detected. Exposure of cultured cardiomyocytes to PLY-expressing pneumococci caused dose-dependent cardiomyocyte contractile dysfunction and death, which was exacerbated by further PLY release following antibiotic treatment. We found that high PLY doses induced extensive cardiomyocyte lysis, but more interestingly, sub-lytic PLY concentrations triggered profound calcium influx and overload with subsequent membrane depolarization and progressive reduction in intracellular calcium transient amplitude, a key determinant of contractile force. This was coupled to activation of signalling pathways commonly associated with cardiac dysfunction in clinical and experimental sepsis and ultimately resulted in depressed cardiomyocyte contractile performance along with rhythm disturbance. Our study proposes a detailed molecular mechanism of pneumococcal toxin-induced cardiac injury and highlights the major translational potential of targeting circulating PLY to protect against cardiac complications during pneumococcal infections

ROCK Inhibitor Is Not Required for Embryoid Body Formation from Singularized Human Embryonic Stem Cells

We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications

Specific Loss of Histone H3 Lysine 9 Trimethylation and HP1γ/Cohesin Binding at D4Z4 Repeats Is Associated with Facioscapulohumeral Dystrophy (FSHD)

Facioscapulohumeral dystrophy (FSHD) is an autosomal dominant muscular dystrophy in which no mutation of pathogenic gene(s) has been identified. Instead, the disease is, in most cases, genetically linked to a contraction in the number of 3.3 kb D4Z4 repeats on chromosome 4q. How contraction of the 4qter D4Z4 repeats causes muscular dystrophy is not understood. In addition, a smaller group of FSHD cases are not associated with D4Z4 repeat contraction (termed “phenotypic” FSHD), and their etiology remains undefined. We carried out chromatin immunoprecipitation analysis using D4Z4–specific PCR primers to examine the D4Z4 chromatin structure in normal and patient cells as well as in small interfering RNA (siRNA)–treated cells. We found that SUV39H1–mediated H3K9 trimethylation at D4Z4 seen in normal cells is lost in FSHD. Furthermore, the loss of this histone modification occurs not only at the contracted 4q D4Z4 allele, but also at the genetically intact D4Z4 alleles on both chromosomes 4q and 10q, providing the first evidence that the genetic change (contraction) of one 4qD4Z4 allele spreads its effect to other genomic regions. Importantly, this epigenetic change was also observed in the phenotypic FSHD cases with no D4Z4 contraction, but not in other types of muscular dystrophies tested. We found that HP1γ and cohesin are co-recruited to D4Z4 in an H3K9me3–dependent and cell type–specific manner, which is disrupted in FSHD. The results indicate that cohesin plays an active role in HP1 recruitment and is involved in cell type–specific D4Z4 chromatin regulation. Taken together, we identified the loss of both histone H3K9 trimethylation and HP1γ/cohesin binding at D4Z4 to be a faithful marker for the FSHD phenotype. Based on these results, we propose a new model in which the epigenetic change initiated at 4q D4Z4 spreads its effect to other genomic regions, which compromises muscle-specific gene regulation leading to FSHD pathogenesis

Mitochondrial oxodicarboxylate carrier deficiency is associated with mitochondrial DNA depletion and spinal muscular atrophy-like disease.

PURPOSE: To understand the role of the mitochondrial oxodicarboxylate carrier (SLC25A21) in the development of spinal muscular atrophy-like disease. METHODS: We identified a novel pathogenic variant in a patient by whole-exome sequencing. The pathogenicity of the mutation was studied by transport assays, computer modeling, followed by targeted metabolic testing and in vitro studies in human fibroblasts and neurons. RESULTS: The patient carries a homozygous pathogenic variant c.695A>G; p.(Lys232Arg) in the SLC25A21 gene, encoding the mitochondrial oxodicarboxylate carrier, and developed spinal muscular atrophy and mitochondrial myopathy. Transport assays show that the mutation renders SLC25A21 dysfunctional and 2-oxoadipate cannot be imported into the mitochondrial matrix. Computer models of central metabolism predicted that impaired transport of oxodicarboxylate disrupts the pathways of lysine and tryptophan degradation, and causes accumulation of 2-oxoadipate, pipecolic acid, and quinolinic acid, which was confirmed in the patient's urine by targeted metabolomics. Exposure to 2-oxoadipate and quinolinic acid decreased the level of mitochondrial complexes in neuronal cells (SH-SY5Y) and induced apoptosis. CONCLUSION: Mitochondrial oxodicarboxylate carrier deficiency leads to mitochondrial dysfunction and the accumulation of oxoadipate and quinolinic acid, which in turn cause toxicity in spinal motor neurons leading to spinal muscular atrophy-like disease