200 research outputs found

    ERCP in Total Situs Viscerum Inversus

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    A 69-year-old cholecystectomized female with known total situs viscerum inversus presented recurrent colicky pain in the left upper abdominal quadrant and jaundice. Laboratory parameters showed increased neutrophils and coniugated bilirubin of 5.53 mg/dl. US and MRCP confirmed total situs viscerum inversus and a dilatation of the intra- and extrahepatic ducts with a peripapillary 13 mm stone. ERCP, sphincterotomy and successful common bile duct stone extraction were performed in the conventional way. ERCP was carried out successfully despite situs inversus maintaining the patient in the prone position with the endoscopist on the right side of the table. Some authors have reported similar cases in whom ERCP was performed in other positions, while this report shows that an experienced endoscopist can achieve the same results in the conventional way as it is possible when anatomical changes, Billroth II or Roux-en-Y, or different positions of the patient, supine or on the left side, are present

    Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO_3^- aerosol during the 2013 Southern Oxidant and Aerosol Study

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    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO_^3−) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na^+ and Ca^(2+), and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO_3 and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH_4NO_3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. Calculation of the rate of the heterogeneous uptake of HNO_3 on mineral aerosol supports the conclusion that aerosol NO_3^− is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO_3^− and HNO_3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning

    Sources, Occurrence and Characteristics of Fluorescent Biological Aerosol Particles Measured Over the Pristine Southern Ocean.

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    In this study, we investigate the occurrence of primary biological aerosol particles (PBAP) over all sectors of the Southern Ocean (SO) based on a 90-day data set collected during the Antarctic Circumnavigation Expedition (ACE) in austral summer 2016-2017. Super-micrometer PBAP (1-16 µm diameter) were measured by a wide band integrated bioaerosol sensor (WIBS-4). Low (3σ) and high (9σ) fluorescence thresholds are used to obtain statistics on fluorescent and hyper-fluorescent PBAP, respectively. Our focus is on data obtained over the pristine ocean, that is, more than 200 km away from land. The results indicate that (hyper-)fluorescent PBAP are correlated to atmospheric variables associated with sea spray aerosol (SSA) particles (wind speed, total super-micrometer aerosol number concentration, chloride and sodium concentrations). This suggests that a main source of PBAP over the SO is SSA. The median percentage contribution of fluorescent and hyper-fluorescent PBAP to super-micrometer SSA was 1.6% and 0.13%, respectively. We demonstrate that the fraction of (hyper-)fluorescent PBAP to total super-micrometer particles positively correlates with concentrations of bacteria and several taxa of pythoplankton measured in seawater, indicating that marine biota concentrations modulate the PBAP source flux. We investigate the fluorescent properties of (hyper-)fluorescent PBAP for several events that occurred near land masses. We find that the fluorescence signal characteristics of particles near land is much more variable than over the pristine ocean. We conclude that the source and concentration of fluorescent PBAP over the open ocean is similar across all sampled sectors of the SO

    Ferric chloride for enhanced coagulation and removal of enteroparasites in water

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    En los últimos años ha tomado relevante importancia la remoción de materia orgánica natural del agua. Está asociada a la producción de olores y gustos desagradables, constituye un sustrato para crecimiento bacteriano, incrementa la necesidad de insumos; pero lo más importante es que genera en el tratamiento de potabilización, subproductos de la desinfección potencialmente cancerígenos. Su eliminación, durante la coagulación, constituye una meta relevante en las plantas de tratamiento. Teniendo en cuenta que la coagulación es una etapa clave en la remoción de enteroparásitos, es importante evaluar si su modificación tiene alguna consecuencia en la efectividad de la eliminación de estos patógenos. Los objetivos del presente trabajo fueron: 1) Evaluar modificaciones de pH en la etapa de coagulación con cloruro férrico, a fin de optimizar la remoción de materia orgánica. 2) Comprobar si estas modificaciones afectan la eliminación de enteroparásitos. Se trabajó con equipo de laboratorio para ensayos de coagulación. Para el recuento de enteroparásitos se aplicó el método de inmunofluorescencia con anticuerpos monoclonales. Se halló que a pH más ácidos la remoción de materia orgánica es mayor Además, se comprobó que la modificación de pH no interfiere en la eliminación de quistes y ooquistes de enteroparásitos en el proceso de coagulación. Se intenta mediante este trabajo realizar aportes a fin de contribuir a disminuir los riesgos que conllevan los subproductos de la cloración, y a su vez minimizar los concernientes a la infección por parásitos.The removal of natural organic matter (NOM) from water has become greatly important. NOM is associated with the production of odors and tastes. It also provides a substrate for bacterial growth and increases chemical costs. However, the fact that it produces potentially carcinogenic disinfection by-products during drinking water treatment is the most relevant. NOM removal during coagulation is an important goal in treatment plants. Considering that coagulation is a key step in the removal of enteroparasites, it is important to evaluate whether its modification has any impact on the effective elimination of these pathogens. The objectives of this study were: 1) to evaluate pH changes in the ferric chloride coagulation stage in order to optimize NOM removal; 2) to determine whether these changes affect the elimination of enteroparasites. Laboratory equipment for coagulation tests was used. Immunofluorescence methods using monoclonal antibodies were applied for counting enteroparasites. It was found that NOM removal was increased at lower pH. It was verified that pH modification does not interfere with the removal of cysts and oocysts in enteroparasites during the coagulation process. This work was done to make a contribution to the issue of reducing the risks involved in disinfection by-products and minimizing those resulting from parasite infections.Comité de Medio Ambient

    Ferric chloride for enhanced coagulation and removal of enteroparasites in water

    Get PDF
    En los últimos años ha tomado relevante importancia la remoción de materia orgánica natural del agua. Está asociada a la producción de olores y gustos desagradables, constituye un sustrato para crecimiento bacteriano, incrementa la necesidad de insumos; pero lo más importante es que genera en el tratamiento de potabilización, subproductos de la desinfección potencialmente cancerígenos. Su eliminación, durante la coagulación, constituye una meta relevante en las plantas de tratamiento. Teniendo en cuenta que la coagulación es una etapa clave en la remoción de enteroparásitos, es importante evaluar si su modificación tiene alguna consecuencia en la efectividad de la eliminación de estos patógenos. Los objetivos del presente trabajo fueron: 1) Evaluar modificaciones de pH en la etapa de coagulación con cloruro férrico, a fin de optimizar la remoción de materia orgánica. 2) Comprobar si estas modificaciones afectan la eliminación de enteroparásitos. Se trabajó con equipo de laboratorio para ensayos de coagulación. Para el recuento de enteroparásitos se aplicó el método de inmunofluorescencia con anticuerpos monoclonales. Se halló que a pH más ácidos la remoción de materia orgánica es mayor Además, se comprobó que la modificación de pH no interfiere en la eliminación de quistes y ooquistes de enteroparásitos en el proceso de coagulación. Se intenta mediante este trabajo realizar aportes a fin de contribuir a disminuir los riesgos que conllevan los subproductos de la cloración, y a su vez minimizar los concernientes a la infección por parásitos.The removal of natural organic matter (NOM) from water has become greatly important. NOM is associated with the production of odors and tastes. It also provides a substrate for bacterial growth and increases chemical costs. However, the fact that it produces potentially carcinogenic disinfection by-products during drinking water treatment is the most relevant. NOM removal during coagulation is an important goal in treatment plants. Considering that coagulation is a key step in the removal of enteroparasites, it is important to evaluate whether its modification has any impact on the effective elimination of these pathogens. The objectives of this study were: 1) to evaluate pH changes in the ferric chloride coagulation stage in order to optimize NOM removal; 2) to determine whether these changes affect the elimination of enteroparasites. Laboratory equipment for coagulation tests was used. Immunofluorescence methods using monoclonal antibodies were applied for counting enteroparasites. It was found that NOM removal was increased at lower pH. It was verified that pH modification does not interfere with the removal of cysts and oocysts in enteroparasites during the coagulation process. This work was done to make a contribution to the issue of reducing the risks involved in disinfection by-products and minimizing those resulting from parasite infections.Comité de Medio Ambient

    Eastern Pacific Emitted Aerosol Cloud Experiment

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    Aerosol–cloud–radiation interactions are widely held to be the largest single source of uncertainty in climate model projections of future radiative forcing due to increasing anthropogenic emissions. The underlying causes of this uncertainty among modeled predictions of climate are the gaps in our fundamental understanding of cloud processes. There has been significant progress with both observations and models in addressing these important questions but quantifying them correctly is nontrivial, thus limiting our ability to represent them in global climate models. The Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) 2011 was a targeted aircraft campaign with embedded modeling studies, using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft and the research vessel Point Sur in July and August 2011 off the central coast of California, with a full payload of instruments to measure particle and cloud number, mass, composition, and water uptake distributions. EPEACE used three emitted particle sources to separate particle-induced feedbacks from dynamical variability, namely 1) shipboard smoke-generated particles with 0.05–1-μm diameters (which produced tracks measured by satellite and had drop composition characteristic of organic smoke), 2) combustion particles from container ships with 0.05–0.2-μm diameters (which were measured in a variety of conditions with droplets containing both organic and sulfate components), and 3) aircraft-based milled salt particles with 3–5-μm diameters (which showed enhanced drizzle rates in some clouds). The aircraft observations were consistent with past large-eddy simulations of deeper clouds in ship tracks and aerosol– cloud parcel modeling of cloud drop number and composition, providing quantitative constraints on aerosol effects on warm-cloud microphysics

    Primary marine aerosol-cloud interactions off the coast of California

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    Primary marine aerosol (PMA)-cloud interactions off the coast of California were investigated using observations of marine aerosol, cloud condensation nuclei (CCN), and stratocumulus clouds during the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets (SOLEDAD) studies. Based on recently reported measurements of PMA size distributions, a constrained lognormal-mode-fitting procedure was devised to isolate PMA number size distributions from total aerosol size distributions and applied to E-PEACE measurements. During the 12 day E-PEACE cruise on the R/V Point Sur, PMA typically contributed less than 15% of total particle concentrations. PMA number concentrations averaged 12 cm^(−3) during a relatively calmer period (average wind speed 12 m/s^1) lasting 8 days, and 71 cm^(−3) during a period of higher wind speeds (average 16 m/s^1) lasting 5 days. On average, PMA contributed less than 10% of total CCN at supersaturations up to 0.9% during the calmer period; however, during the higher wind speed period, PMA comprised 5–63% of CCN (average 16–28%) at supersaturations less than 0.3%. Sea salt was measured directly in the dried residuals of cloud droplets during the SOLEDAD study. The mass fractions of sea salt in the residuals averaged 12 to 24% during three cloud events. Comparing the marine stratocumulus clouds sampled in the two campaigns, measured peak supersaturations were 0.2 ± 0.04% during E-PEACE and 0.05–0.1% during SOLEDAD. The available measurements show that cloud droplet number concentrations increased with >100 nm particles in E-PEACE but decreased in the three SOLEDAD cloud events

    Circum-Antarctic abundance and properties of CCN and INPs

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    Aerosol particles acting as cloud condensation nuclei (CCN) or ice-nucleating particles (INPs) play a major role in the formation and glaciation of clouds. Thereby they exert a strong impact on the radiation budget of the Earth. Data on abundance and properties of both types of particles are sparse, especially for remote areas of the world, such as the Southern Ocean (SO). In this work, we present unique results from ship-borne aerosol-particle-related in situ measurements and filter sampling in the SO region, carried out during the Antarctic Circumnavigation Expedition (ACE) in the austral summer of 2016–2017. An overview of CCN and INP concentrations over the Southern Ocean is provided and, using additional quantities, insights regarding possible CCN and INP sources and origins are presented. CCN number concentrations spanned 2 orders of magnitude, e.g. for a supersaturation of 0.3 % values ranged roughly from 3 to 590 cm−3. CCN showed variable contributions of organic and inorganic material (inter-quartile range of hygroscopicity parameter κ from 0.2 to 0.9). No distinct size dependence of κ was apparent, indicating homogeneous composition across sizes (critical dry diameter on average between 30 and 110 nm). The contribution of sea spray aerosol (SSA) to the CCN number concentration was on average small. Ambient INP number concentrations were measured in the temperature range from −5 to −27 ∘C using an immersion freezing method. Concentrations spanned up to 3 orders of magnitude, e.g. at −16 ∘C from 0.2 to 100 m−3. Elevated values (above 10 m−3 at −16 ∘C) were measured when the research vessel was in the vicinity of land (excluding Antarctica), with lower and more constant concentrations when at sea. This, along with results of backward-trajectory analyses, hints towards terrestrial and/or coastal INP sources being dominant close to ice-free (non-Antarctic) land. In pristine marine areas INPs may originate from both oceanic sources and/or long-range transport. Sampled aerosol particles (PM10) were analysed for sodium and methanesulfonic acid (MSA). Resulting mass concentrations were used as tracers for primary marine and secondary aerosol particles, respectively. Sodium, with an average mass concentration around 2.8 µg m−3, was found to dominate the sampled, identified particle mass. MSA was highly variable over the SO, with mass concentrations up to 0.5 µg m−3 near the sea ice edge. A correlation analysis yielded strong correlations between sodium mass concentration and particle number concentration in the coarse mode, unsurprisingly indicating a significant contribution of SSA to that mode. CCN number concentration was highly correlated with the number concentration of Aitken and accumulation mode particles. This, together with a lack of correlation between sodium mass and Aitken and accumulation mode number concentrations, underlines the important contribution of non-SSA, probably secondarily formed particles, to the CCN population. INP number concentrations did not significantly correlate with any other measured aerosol physico-chemical parameter.</p

    Hygroscopic properties of smoke-generated organic aerosol particles emitted in the marine atmosphere

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    During the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE), a plume of organic aerosol was produced by a smoke generator and emitted into the marine atmosphere from aboard the R/V Point Sur. In this study, the hygroscopic properties and the chemical composition of the plume were studied at plume ages between 0 and 4 h in different meteorological conditions. In sunny conditions, the plume particles had very low hygroscopic growth factors (GFs): between 1.05 and 1.09 for 30 nm and between 1.02 and 1.1 for 150 nm dry size at a relative humidity (RH) of 92%, contrasted by an average marine background GF of 1.6. New particles were produced in large quantities (several 10 000 cm^−3), which lead to substantially increased cloud condensation nuclei (CCN) concentrations at supersaturations between 0.07 and 0.88%. Ratios of oxygen to carbon (O : C) and water-soluble organic mass (WSOM) increased with plume age: from < 0.001 to 0.2, and from 2.42 to 4.96 μg m^−3, respectively, while organic mass fractions decreased slightly (~ 0.97 to ~ 0.94). High-resolution aerosol mass spectrometer (AMS) spectra show that the organic fragment m/z 43 was dominated by C_(2)H_(3)O^+ in the small, new particle mode and by C_(3)H_(7)^+ in the large particle mode. In the marine background aerosol, GFs for 150 nm particles at 40% RH were found to be enhanced at higher organic mass fractions: an average GF of 1.06 was observed for aerosols with an organic mass fraction of 0.53, and a GF of 1.04 for an organic mass fraction of 0.35

    The Ny-Ã…lesund Aerosol Cloud Experiment (NASCENT): Overview and First Results

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    The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds, which modulate the solar and terrestrial radiative fluxes and, thus, determine the surface energy budget. However, the interactions among clouds, aerosols, and radiative fluxes in the Arctic are still poorly understood. To address these uncertainties, the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) study was conducted from September 2019 to August 2020 in Ny-Ålesund, Svalbard. The campaign’s primary goal was to elucidate the life cycle of aerosols in the Arctic and to determine how they modulate cloud properties throughout the year. In situ and remote sensing observations were taken on the ground at sea level, at a mountaintop station, and with a tethered balloon system. An overview of the meteorological and the main aerosol seasonality encountered during the NASCENT year is introduced, followed by a presentation of first scientific highlights. In particular, we present new findings on aerosol physicochemical and molecular properties. Further, the role of cloud droplet activation and ice crystal nucleation in the formation and persistence of mixed-phase clouds, and the occurrence of secondary ice processes, are discussed and compared to the representation of cloud processes within the regional Weather Research and Forecasting Model. The paper concludes with research questions that are to be addressed in upcoming NASCENT publications
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