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Nitrogen oxides (NOx = NO + NO2) emissions are estimated in three regions in the Northern hemisphere, generally located in North America, Europe, and East Asia, by calculating the directional derivatives of NO2 column amounts observed by the TROPOMI instrument with respect to the horizontal wind vectors. We present monthly averaged emissions from 1 May 2018 to 31 January 2023 to capture variations before and after the COVID-19 pandemic. We focus on a diverse collection of 54 cities, 18 in each region. A spatial resolution of 0.04° resolves intracity emission variations and reveals NOx emission hot spots at city cores, industrial areas, and sea ports. For each selected city, COVID-19-induced changes in NOx emissions are estimated by comparing monthly and annually averaged values to the pre-COVID-19 year of 2019. While emission reductions are initially found during the first outbreak of COVID-19 in early 2020 in most cities, the cities' paths diverge afterwards. We group the selected cities into 4 clusters according to their normalized annual NOx emissions in 2019–2022 using an unsupervised learning algorithm. All but one selected North American cities fall into cluster 1 characterized by weak emission reduction in 2020 (−7 % relative to 2019) and increase in 2022 by +5 %. Cluster 2 contains mostly European cities and is characterized by the largest reduction in 2020 (−31 %), whereas the selected East Asian cities generally fall into clusters 3 and 4 with the largest impacts in 2022 (−25 % and −37 %). This directional derivative approach has been implemented in object-oriented, open-source Python and is available publicly for high-resolution and low-latency emission estimation for different regions, atmospheric species, and satellite instruments.

Biomass burning emits vapors and aerosols into the atmosphere that can rapidly evolve as smoke plumes travel downwind and dilute, affecting climate- and health-relevant properties of the smoke. To date, theory has been unable to explain observed variability in smoke evolution. Here, we use observational data from the Biomass Burning Observation Project (BBOP) field campaign and show that initial smoke organic aerosol mass concentrations can help predict changes in smoke aerosol aging markers, number concentration, and number mean diameter between 40–262 nm. Because initial field measurements of plumes are generally >10 min downwind, smaller plumes will have already undergone substantial dilution relative to larger plumes and have lower concentrations of smoke species at these observations closest to the fire. The extent to which dilution has occurred prior to the first observation is not a directly measurable quantity. We show that initial observed plume concentrations can serve as a rough indicator of the extent of dilution prior to the first measurement, which impacts photochemistry, aerosol evaporation, and coagulation. Cores of plumes have higher concentrations than edges. By segregating the observed plumes into cores and edges, we find evidence that particle aging, evaporation, and coagulation occurred before the first measurement. We further find that on the plume edges, the organic aerosol is more oxygenated, while a marker for primary biomass burning aerosol emissions has decreased in relative abundance compared to the plume cores. Finally, we attempt to decouple the roles of the initial concentrations and physical age since emission by performing multivariate linear regression of various aerosol properties (composition, size) on these two factors.

Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM), with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP version 1.0 presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

Water is our most valuable natural resource, and is used to support the demands of industry, agriculture, hydroelectric power generation, and municipalities. Water also sustains Montana’s booming recreation and tourism economy and maintains the diverse freshwater ecosystems that provide natural goods and services and promote human well-being. As our population continues to grow, and the collective demand for water increases, it is imperative that we carefully assess how our water is used, as well as how changes in water distribution, management, and governance are likely to influence its availability in the future. This is especially important in the context of a changing climate.

WRF-Chem and a modified version of the ECLIPSE 5a emission inventory were used to investigate the sources impacting black carbon (BC) deposition to the Himalaya, Karakoram, and Hindu Kush (HKHK) region. This work extends previous studies by simulating deposition to the HKHK region not only under current conditions, but also in the 2040-2050 period under two realistic emission scenarios and in three different phases of the El Nino-Southern Oscillation (ENSO). Under current conditions, sources from outside our South Asian modelling domain have a similar impact on total BC deposition to the HKHK region (35-87%, varying with month) as South Asian anthropogenic sources (13-62%). Industry (primarily brick kilns) and residential solid fuel burning combined account for 45-66% of the in-domain anthropogenic BC deposition to the HKHK region. Under a no further control emission scenario for 2040-2050, the relative contributions to BC deposition in the HKHK region are more skewed toward in-domain anthropogenic sources (45-65%) relative to sources outside the domain (26-52%). The in-domain anthropogenic BC deposition has significant contributions from industry (32-42%), solid fuel burning (17-28%), and diesel fuel burning (17-27%). Under a scenario in which emissions in South Asia are mitigated, the relative cotribution from South Asian anthropogenic sources is significantly reduced to 11-34%. The changes due to phase of ENSO do not seem to follow consistent patterns with ENSO. Future work will use the high-resolution deposition maps developed here to determine the impact of different sources of BC on glacier melt and water availability in the region.

The self-interaction error (SIE), i.e. unphysical interactions of electrons with themselves, has plagued developers and users of Density Functional Approximations (DFAs) since the inception of Density Functional Theory (DFT). Formally, it can be separated into the one-electron and many-electron SIE; herein we present one of the most comprehensive studies of the first. While we focus mostly on the total SIE, we also make use of two different decompositions. The first is a separation into functional and density-driven errors as championed by Sim, Burke and co-workers [J. Phys. Chem. Lett., 2018, 9, 6385–6392]; the second separates the error into exchange, correlation, and one-electron components, with the latter being a density error that has not been discussed in this form before. After investigating the familiar hydrogen atom and dihydrogen cation, we establish a relationship between the SIE and the nuclear charge with the help of a series of heavier hydrogenic analogues. For the mononuclear systems and the diatomics at the dissociation limit, this relationship is linear in nature with prominent exceptions, mostly belonging to the Minnesota and range-separated (double-)hybrid DFAs. For the first time, we also show how the magnitude of the SIE depends on the underlying atomic-orbital basis set and how DFAs that rely on a popular van-der-Waals DFT type London-dispersion term exhibit “self-dispersion”. We find that range separation is not a panacea for solving the one-electron SIE. DFAs that have been developed to be one-electron SIE free for one system, such as the hydrogen atom, show larger errors for heavier hydrogenic systems. Often, one-electron SIE-free DFAs rely on fortuitous error cancellation between their exchange and correlation components. An analysis of the most robust methods for general applications to date reveals that they suffer moderately from the one-electron SIE, while DFAs that are nearly SIE-free do not perform well in applications. Implicit in the continued existence of the one-electron SIE is that well-performing DFAs continue to suffer insufficiencies at their fundamental levels that are being compensated for by the SIE. Our analysis includes more than 250 000 datapoints, resulting in multiple insights that may drive future developments of new DFAs or SIE corrections.

We developed and evaluated three types of statistical forecasting models (quantitative, probabilistic, and classification) for predicting the maximum daily 8-hour average concentration of ozone based on meteorological and ozone monitoring data for six Texas urban areas from 2009 to 2015. The quantitative and probabilistic forecasting models were generalized additive models (GAMs), whereas the classification forecast used the random forest machine learning method. We found that for the quantitative forecasting models, five of the eight predictors (the day of week, day of the year, water vapor density, wind speed, and previous day’s ozone measurement) were significant at the α = 0.001 level for all urban areas, whereas the other three varied in significance according to the location. The quantitative forecasting for the 2016 ozone season agreed well with the associated measurements (R2 of ~0.70), but it tended to under-predict the ozone level for the days with the highest concentrations. By contrast, the probabilistic forecasting models showed little accuracy in determining the probability of concentrations exceeding policy-relevant thresholds during this season. The success rate for the random forest classification models typically exceeded 75% and would likely increase if the training data sets contained more extreme events.

Biomass burning emits vapors and aerosols into the atmosphere that can rapidly evolve as smoke plumes travel downwind and dilute, affecting climate- and health-relevant properties of the smoke. To date, theory has been unable to explain variability in smoke evolution. Here, we use observational data from the BBOP field campaign and show that initial smoke concentrations can help predict changes in smoke aerosol aging markers, number, and diameter. Because initial field measurements of plumes are generally > 10 minutes downwind, smaller plumes will have already undergone substantial dilution relative to larger plumes. However, the extent to which dilution has occurred prior to the first observation is not a measurable quantity. Hence, initial observed concentrations can serve as an indicator of dilution, which impacts photochemistry and aerosol evaporation. Cores of plumes have higher concentrations than edges. By segregating the observed plumes into cores and edges, we infer that particle aging, evaporation, and coagulation occurred before the first measurement, and we find that edges generally undergo higher increases in oxidation tracers, more decreases in semivolatile compounds, and less coagulation than the cores.

Climate change presents a complex set of challenges for natural resource managers across North America. Despite recognition that climate change poses serious threats to species, ecosystems, and human communities, implementation of adaptation measures is not yet happening on a broad scale. Among different regions, a range of climate change trajectories, varying political contexts, and diverse social and ecological systems generate a myriad of factors that can affect progress on climate change adaptation implementation. In order to understand the general versus site-specific nature of barriers and opportunities influencing implementation, we surveyed and interviewed practitioners, decision-makers, and scientists involved in natural resource management in four different North American regions, northern Ontario (Canada), the Adirondack State Park (US), Arctic Alaska (US), and the Transboundary Rocky Mountains (US and Canada). Common barriers among regions related to a lack of political support and financial resources, as well as challenges related to translating complex and interacting effects of climate change into management actions. Opportunities shared among regions related to collaboration, funding, and the presence of strong leadership. These commonalities indicate the importance of cross-site learning about ways to leverage opportunities and address adaptation barriers; however, regional variations also suggest that adaptation efforts will need to be tailored to fit specific ecological, political, social and economic contexts. Comparative findings on the similarities and differences in barriers and opportunities, as well as rankings of barriers and opportunities by region, offers important contextual insights into how to further refine efforts to advance adaptation actions in those regions.

Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM) version 1.0, with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

Biomass burning is a major source of atmospheric particulate matter (PM) with impacts on health, climate, and air quality. The particles and vapors within biomass burning plumes undergo chemical and physical aging as they are transported downwind. Field measurements of the evolution of PM with plume age range from net decreases to net increases, with most showing little to no change. In contrast, laboratory studies tend to show significant mass increases on average. On the other hand, similar effects of aging on the average PM composition (e.g., oxygen-to-carbon ratio) are reported for lab and field studies. Currently, there is no consensus on the mechanisms that lead to these observed similarities and differences. This review summarizes available observations of aging-related biomass burning aerosol mass concentrations and composition markers, and discusses four broad hypotheses to explain variability within and between field and laboratory campaigns: (1) variability in emissions and chemistry, (2) differences in dilution/entrainment, (3) losses in chambers and lines, and (4) differences in the timing of the initial measurement, the baseline from which changes are estimated. We conclude with a concise set of research needs for advancing our understanding of the aging of biomass burning aerosol.

Biomass burning is a significant global source of aerosol number and mass. In fresh biomass burning plumes, aerosol coagulation reduces aerosol number and increases the median size of aerosol size distributions, impacting aerosol radiative effects. Near-source biomass burning aerosol coagulation occurs at spatial scales much smaller than the grid boxes of global and many regional models. To date, these models have ignored sub-grid coagulation and instantly mixed fresh biomass burning emissions into coarse grid boxes. A previous study found that the rate of particle growth by coagulation within an individual smoke plume can be approximated using the aerosol mass emissions rate, initial size distribution median diameter and modal width, plume mixing depth, and wind speed. In this paper, we use this parameterization of sub-grid coagulation in the GEOS-Chem–TOMAS (TwO-Moment Aerosol Sectional) global aerosol microphysics model to quantify the impacts on global aerosol size distributions, the direct radiative effect, and the cloud-albedo aerosol indirect effect. We find that inclusion of biomass burning sub-grid coagulation reduces the biomass burning impact on the number concentration of particles larger than 80 nm (a proxy for CCN-sized particles) by 37 % globally. This cloud condensation nuclei (CCN) reduction causes our estimated global biomass burning cloud-albedo aerosol indirect effect to decrease from −76 to −43 mW m−2. Further, as sub-grid coagulation moves mass to sizes with more efficient scattering, including it increases our estimated biomass burning all-sky direct effect from −224 to −231 mW m−2, with assumed external mixing of black carbon and from −188 to −197 mW m−2 and with assumed internal mixing of black carbon with core-shell morphology. However, due to differences in fire and meteorological conditions across regions, the impact of sub-grid coagulation is not globally uniform. We also test the sensitivity of the impact of sub-grid coagulation to two different biomass burning emission inventories to various assumptions about the fresh biomass burning aerosol size distribution and to two different timescales of sub-grid coagulation. The impacts of sub-grid coagulation are qualitatively the same regardless of these assumptions.

Myofibromas are benign neoplasms of myofibroblastic origin, rarely encountered in the oral cavity. Limited awareness of the clinical features of these lesions risks misdiagnosis of more sinister pathology. The objective of this report is to highlight the potential diversity of oral lesions by describing an uncommon presentation of a myofibroma. The case reveals the diagnostic difficulties encountered, along with postoperative complications, which exemplify the remarkable healing capacity of the oral cavity.

GBD 2017 Causes of Death Collaborators. Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980–2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet 2018; 392: 1736–88—The bottom row in figure 7 was cut off. This correction has been made to the online version as of Nov 9, 2018, and has been made to the printed Article. © 2018 Elsevier Ltd

Simultaneous high-time-resolution measurements of atmospheric NH3 ,H NO3, soluble gas-phase chloride, and aerosol species were made in Houston, TX, from August 5, 2010 to August 9, 2010. Gaseous NH3 was measured using a 10.4-mm external cavity quantum cascade laser-based sensor employing conventional photo-acoustic spectroscopy, while gaseous HNO3 and HCl were sampled using a mist chambereion chromatograph (IC) system. Particle chemical composition was determined using a particle-into-liquidsamplereIC system. There was a large amount of variability in the gas phase mixing ratios of NH3 (3.0 � 2.5 ppb), HNO3 (287.4 � 291.6 ppt), and HCl (221.3 � 260.7 ppt). Elevated NH3 levels occurred around mid-day when NH4 þ (0.5 � 1.0 mgm � 3 ) andSO4 2� (4.5 � 4.3mgm � 3 ) alsoincreasedconsiderably,indicating that NH3 likely influenced aerosol particle mass. By contrast, the formation of NH4NO3 and NH4Cl was not observed during the measurements. Point sources (e.g., power plant and chemical plant) might be potential contributors to the enhancements in NH3 at the measurement site under favorable meteorological conditions. Increased particle number concentrations were predicted by the SAM-TOMAS model downwind of a large coal-fired power plant when NH3 emissions (based on these measurements) were included, highlighting the potential importance of NH3 with respect to particle number concentration. Separate measurements also indicate the role of NH3 in new particle formation in Houston under low-sulfur conditions.

Objectives Several plaque and lesion characteristics have been associated with an increased risk for procedural stroke during or shortly after carotid artery stenting (CAS). While technical advancements in stent design and cerebral protection devices (CPD) may help reduce the procedural stroke risk, and anatomy remains important, tailoring stenting procedures according to plaque and lesion characteristics might be a useful strategy in reducing stroke associated with CAS. In this descriptive report of the ongoing Asymptomatic Carotid Surgery Trial-2 (ACST-2), it was assessed whether choice for stent and use or type of CPD was influenced by plaque and lesion characteristics. Materials and methods Trial patients who underwent CAS between 2008 and 2015 were included in this study. Chi-square statistics were used to study the effects of plaque echolucency, ipsilateral preocclusive disease (90–99%), and contralateral high-grade stenosis (>50%) or occlusion of the carotid artery on interventionalists' choice for stent and CPD. Differences in treatment preference between specialties were also analysed. Results In this study, 831 patients from 88 ACST-2 centres were included. Almost all procedures were performed by either interventional radiologists (50%) or vascular surgeons (45%). Plaque echolucency, ipsilateral preocclusive disease (90–99%), and significant contralateral stenosis (>50%) or occlusion did not affect the choice of stent or either the use of cerebral protection and type of CPD employed (i.e., filter/flow reversal). Vascular surgeons used a CPD significantly more often than interventional radiologists (98.6% vs. 76.3%; p < .001), but this choice did not appear to be dependent on patient characteristics. Conclusions In ACST-2, plaque characteristics and severity of stenosis did not primarily determine interventionalists' choice of stent or use or type of CPD, suggesting that other factors, such as vascular anatomy or personal and centre preference, may be more important. Stent and CPD use was highly heterogeneous among participating European centres.

NH3 retrievals from the NASA Tropospheric Emission Spectrometer (TES), as well as surface and aircraft observations of NH3(g) and submicron NH4(p), are to used to evaluate modelled concentrations of NH3(g) and NH4(p) from the Community Multiscale Air Quality (CMAQ) model in the San Joaquin Valley (SJV) during the California Research at the Nexus of Air Quality and Climate Change (CalNex) campaign. We find that simulations of NH3 driven with the California Air Resources Board (CARB) CalNex emission inventory are qualitatively and spatially consistent with TES satellite observations, with a correlation coefficient (r2) of 0.54. However, the surface observations at Bakersfield indicate a missing diurnal cycle in the model bias, with CMAQ overestimating surface NH3 at night and underestimating it during the day. The surface, satellite, and aircraft observations all suggest that the afternoon NH3 emissions in the CARB inventory are underestimated by at least a factor of two, while the night-time overestimate of NH3(g) is likely due to a combination of overestimated NH3 emissions, underestimated deposition, and insufficient vertical mixing in the WRF meteorological fields used to drive CMAQ. We used the surface observations at Bakersfield to derive an empirical diurnal cycle of NH3 emissions in the SJV, in which night-time and midday emissions differed by about a factor of 4.5. Adding this diurnal profile to the CMAQ simulations while keeping the daily NH3 emissions constant at the CARB values significantly improved the model performance at night, but sizable errors (up to 15 ppbv) in night-time NH3 remain, likely due to remaining errors in vertical mixing at night. The model performance is slightly degraded during the afternoon when the diurnal cycle is adjusted, but this may reflect relatively small (~ 20 %) errors in the total NH3 emissions rather than remaining errors in the diurnal cycle. Running CMAQv5.0.2 with bi-directional NH3 flux also improves model performance on a similar scale, while combining bi-directional NH3 fluxes and adjusted emissions significantly reduces the model bias at night.

Reliable assays for accurate titration of influenza virus in infectious samples are pivotal to both influenza research and vaccine development. A titration assay adopted commonly for this purpose is the plaque assay on Madin-Darby canine kidney (MDCK) cells, despite it being time and labour consuming. A novel assay is described for titration of influenza viruses based on the detection of intracellular viral nucleoprotein (NP) by fluorescence-activated cell sorting (FACS). By using a panel of viruses of different type, subtype and origin, it is demonstrated that there is a mathematical correlation between titres measured by immunotitration and by classical plaque assay on MDCK cells. Moreover, the availability of NP antibodies specific for type A or type B influenza virus ensures the specificity of the assay. Based on speed, accuracy and specificity, it is concluded that the FACS-based immunotitration of influenza virus represents a valid and efficient alternative to the classical plaque assay.

Within minutes after emission, rapid, complex photochemistry within a biomass burning smoke plume can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed burn in chaparral, which was sampled over California in November 2009. We demonstrate the use of a method for simultaneously accounting for the impact of the unidentified semi-volatile to extremely low volatility organic compounds (here collectively called "SVOCs") on the formation of OA (using the Volatility Basis Set) and O3 (using the concept of mechanistic reactivity). We show that this method can successfully simulate the observations of O3, OA, PAN, NOx, and C2H4 to within measurement uncertainty using reasonable assumptions about the chemistry of the unidentified SVOCs. These assumptions were: (1) a~reaction rate constant with OH of ~10−11cm3s−1, (2) a significant fraction (~50%) of the RO2 + NO reaction resulted in fragmentation, rather than functionalization, of the parent SVOC, (3) ~1.1 molecules of O3 were formed for every molecule of SVOC that reacted, (4) ~60% of the OH that reacted with the unidentified SVOCs was regenerated as HO2, and (5) that ~50% of the NO that reacted with the SVOC peroxy radicals was lost, presumably to organic nitrate formation. Additional evidence for the fragmentation pathway is provided by the observed rate of formation of acetic acid, which is consistent with our assumed fragmentation rate. This method could provide a way for classifying different smoke plume observations in terms of the average chemistry of their SVOCs, and could be used to study how the chemistry of these compounds (and the O3 and OA they form) varies between plumes.

New-particle nucleation within coal-fired power-plant plumes can have large effects on particle number concentrations, particularly near source regions, with implications for human health and climate. In order to resolve the formation and growth of particles in these plumes, we have integrated TwO-Moment Aerosol Sectional (TOMAS) microphysics in the System for Atmospheric Modelling (SAM), a large-eddy simulation/cloud-resolving model (LES/CRM). We have evaluated this model against aircraft observations for three case studies, and the model reproduces well the major features of each case. Using this model, we have shown that meteorology and background aerosol concentrations can have strong effects on new-particle formation and growth in coal-fired power-plant plumes, even if emissions are held constant. We subsequently used the model to evaluate the effects of SO2 and NOx pollution controls on newparticle formation in coal-fired power-plant plumes. We found that strong reductions in NOx emissions without concurrent reductions in SO2 emissions may increase new-particle formation, due to increases in OH formation within the plume. We predicted the change in new-particle formation due to changes in emissions between 1997 and 2010 for 330 coal-fired power plants in the US, and we found a median decrease of 19% in new-particle formation. However, the magnitude and sign of the aerosol changes depend greatly on the relative reductions in NOx and SO2 emissions in each plant. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed, however, to better quantify these effects.

Nucleation in coal-fired power-plant plumes can greatly contribute to particle number concentrations near source regions. The changing emissions rates of SO2 and NOx due to pollution-control technologies over recent decades may have had a significant effect on aerosol formation and growth in the plumes, with ultimate implications for climate and human health. We use the System for Atmospheric Modeling (SAM) large-eddy simulation model with the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm to model the nucleation in plumes of coal-fired plants. We test a range of cases with varying emissions to simulate the implementation of emissions-control technologies between 1997 and 2010. For the W.A. Parish power plant (near Houston, TX) during this time period, NOx emissions were reduced by ~90%, while SO2 emissions decreased by ~30%. Increases in plume OH (due to the reduced NOx) produced enhanced SO2 oxidation and particle nucleation despite the reduction in SO2 emissions. These results suggest that NOx emissions may strongly regulate particle nucleation and growth in power-plant plumes. Comparison of model results with airborne measurements made in the W.A. Parish power-plant plume in 2000 and 2006 confirm the importance of NOx emissions on new particle formation, yet also highlight the substantial effect of background aerosol loadings on this process. A wide range of NOx and SO2 emissions were modeled to understand how they affect particle formation in the plume. Particle formation generally increases with SO2 emission, while NOx shows two different regimes: increasing particle formation with increasing NOx under low-NOx emissions and decreasing particle formation with increasing NOx under high-NOx emissions. Finally, we calculate emissions statistics of 330 coal-fired power plants in the US in 1997 and 2010, and the model results show a median decrease of 19% in particle formation ratesfrom 1997 to 2010 (whereas the W.A. Parish case study showed an increase). These results suggest that there may be important climate implications of power-plant controls due to changes in plume chemistry and microphysics. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed to better quantify these effects.

Sixty-three year-old-man presented with macroscopic haematuria and passage of debris per urethra. His prostate was suspicious of a T2a tumour and his PSA was 11.1 μg/l but his trans rectal ultra sound scan (TRUS) and biopsies were negative for malignancy. In the past, he had trans urethral resection (TUR) of prostate for benign hyperplasia, excision of nasopharyngeal fibroma and superficial spreading melanoma of the thigh and had supraventricular tachycardia but no ischaemic heart disease. Investigations for haematuria revealed normal upper tracts on USS. On urethroscopy, there was an annular bulbar stricture requiring urethral dilatation. Residual prostate was oedematous, vascular but non-occlusive. In the bladder, there was a yellowish white solitary plaque up to 1.5 cm on the posterior wall (Figure 1) Cold cup biopsy showed collection of macrophages with foamy cytoplasm (foam cells) in the lamina propria with a normal overlying urothelium. There was no dysplasia or neoplasia. Appearances were those of a xanthoma (Figure 2a, 2b) Blood counts, renal function, random blood sugar and LFTs were normal as was the thyroid and lipid profile. Urine cytology was normal. Follow-up cystoscopy at 6 months revealed no further lesions in the lower urinary tract and no change in the appearance of the original xanthoma. There was no evidence of transitional cell carcinoma of the bladder. There were no other xanthomatous lesions.

The field of molecular biology is an important part of research into neoplastic conditions. Much of this research requires access to human tissue samples, which may need to be collected and stored in a specific way, according to the type of study for which they are intended. Anonymous clinical information about the samples enables researchers to apply results to different patient groups. Access to stored tissues is particularly important in head and neck disease research as many neoplastic conditions affecting this area have a relatively low incidence. Consequently, it may take a long time to build up enough individual cases to make a study worthwhile.We describe here the current legal, ethical and practical issues of research tissue banking, with regard to head and neck disease.

BACKGROUND—Most patients with haemochromatosis have mutations of the HFE gene. However, the risk to people with HFE mutations of developing disease manifestations of haemochromatosis is not known. AIMS—To determine the risk of developing cirrhosis and liver cancer in individuals with HFE mutations in a population where few people were being treated for haemochromatosis. METHODS—215 archive biopsy specimens of liver cancer (n=34) and cirrhosis (n=190) were retrieved from histology archives. Blood samples from 1000 individuals from the normal population were also collected. DNA was extracted from the biopsy specimens and exons 2 and 4 of the HFE gene were amplified using polymerase chain reaction. The products were analysed for the C282Y (845A) and H63D (187G) mutations. RESULTS—Three (8.8%) patients from the liver cancer group were homozygous for the C282Y mutation. Five (2.6%) patients from the cirrhosis group were homozygous for the C282Y mutation. One case fell in both the liver cancer and cirrhosis groups. C282Y homozygosity was thus significantly more frequent in both groups than in the normal population. These 215 cases are representative of a population of about 250 000 over 20 years. During this period we estimate that about 260 births or deaths of C282Y homozygous individuals occurred within this population. CONCLUSIONS—A diagnosis of liver cancer or cirrhosis is rare in the lifetime of individuals from this population who are homozygous for the C282Y mutation (2.5%; upper 95% confidence interval (CI) = 8%). Similarly liver disease is rare among C282Y/H63D compound heterozygotes (1%; upper 95% CI = 3.5%). Keywords: haemochromatosis; HLA-H; C282Y; H63D; penetrance

In 2005, a 68-year-old woman presented to the surgical outpatient clinic with a 6-year history of swelling in the right groin, which recently became larger and was causing her discomfort. Her obste...

Earlier workers have suggested a possible fibrinolytic effect using prostaglandin or prostaglandin analogues. Despite using maximum tolerated doses of the prostaglandin analogue Iloprost, we have been unable to demonstrate any significant effect on fibrinolysis in patients with stage IV peripheral vascular disease (Fontaine classification).

Background Endovascular intervention has only recently been used for the treatment of carotid disease. The 30-day outcome of 226 endovascular carotid interventions for atherosclerosis performed since August 1993 is presented. Methods All patients were symptomatic apart from four (2 per cent) who underwent intervention before coronary artery bypass. The last presenting symptom was transient ischaemic attack (TIA) (40 per cent), amaurosis fugax (31 per cent), retinal artery occlusion (3 per cent) and stroke (24 per cent). A moderate stenosis (50–69 per cent; North American Symptomatic Carotid Endarterectomy Trial technique) was present in 24 patients (11 per cent), a severe stenosis (70–95 per cent) in 144 (64 per cent), and a preocclusive stenosis (more than 95 per cent) in 58 (26 per cent). The contralateral internal carotid artery was significantly diseased (greater than 70 per cent) or occluded in 65 patients (29 per cent). All patients were pretreated with aspirin; 5000 units heparin and 1·2 mg atropine were given during the procedure. Initially, stents were reserved for treating residual stenosis after angioplasty (16 of 108 procedures). Later, a change was made to primary stenting (116 procedures). A femoral approach was used for all patients. Results At 30 days there were four deaths (2 per cent) and eight disabling strokes (4 per cent) (death and disabling stroke rate 5 per cent; death and all-strokes rate 8 per cent). For angioplasty and selective stenting the death and disabling stroke rate and the death and all-strokes rate were 6 and 9 per cent respectively, compared with 5 and 8 per cent for primary stenting (P not significant). However, there was a significant difference between the incidence of all adverse events (31 versus 11 per cent) as a result of fewer TIAs associated with primary stenting. During the same interval, 300 carotid endarterectomies (similar indications and severity of disease) were performed. There were six deaths (2 per cent) and eight disabling strokes (3 per cent) (death and disabling stroke rate 5 per cent; death and all-strokes rate 6 per cent). The complications of both endovascular intervention and conventional endarterectomy seem to be improving with time. Conclusion These data confirm the feasibility of endovascular carotid intervention and highlight the need for a large randomized trial comparing it with conventional surgery. The benefit of stents and cerebral protection systems also requires further investigation.