Small intestinal bacterial overgrowth mimicking acute flare as a pitfall in patients with Crohn's Disease

<p>Abstract</p> <p>Background</p> <p>Small intestinal bacterial overgrowth (SIBO) is characterized by excessive proliferation of colonic bacterial species in the small bowel. Potential causes of SIBO include fistulae, strictures or motility disturbances. Hence, patients with Crohn's Disease (CD) are especially predisposed to develop SIBO. As result, CD patients may experience malabsorption and report symptoms such as weight loss, watery diarrhea, meteorism, flatulence and abdominal pain, mimicking acute flare in these patients.</p> <p>Methods</p> <p>One-hundred-fifty patients with CD reporting increased stool frequency, meteorism and/or abdominal pain were prospectively evaluated for SIBO with the Hydrogen Glucose Breath Test (HGBT).</p> <p>Results</p> <p>Thirty-eight patients (25.3%) were diagnosed with SIBO based on positive findings at HGBT. SIBO patients reported a higher rate of abdominal complaints and exhibited increased stool frequency (5.9 vs. 3.7 bowel movements/day, p = 0.003) and lower body weight (63.6 vs 70.4 kg, p = 0.014). There was no correlation with the Crohn's Disease Activity Index. SIBO was significantly more frequent in patients with partial resection of the colon or multiple intestinal surgeries; there was also a clear trend in patients with ileocecal resection that did not reach statistical significance. SIBO rate was also higher in patients with affection of both the colon and small bowel, while inflammation of the (neo)terminal ileum again showed only tendential association with the development of SIBO.</p> <p>Conclusion</p> <p>SIBO represents a frequently ignored yet clinically relevant complication in CD, often mimicking acute flare. Because symptoms of SIBO are often difficult to differentiate from those caused by the underlying disease, targeted work-up is recommended in patients with corresponding clinical signs and predisposing factors.</p

Implementation of electrochemical, optical and denuder-based sensors and sampling techniques on UAV for volcanic gas measurements : examples from Masaya, Turrialba and Stromboli volcanoes

Volcanoes are a natural source of several reactive gases (e.g., sulfur and halogen containing species) and nonreactive gases (e.g., carbon dioxide) to the atmosphere. The relative abundance of carbon and sulfur in volcanic gas as well as the total sulfur dioxide emission rate from a volcanic vent are established parameters in current volcanomonitoring strategies, and they oftentimes allow insights into subsurface processes. However, chemical reactions involving halogens are thought to have local to regional impact on the atmospheric chemistry around passively degassing volcanoes. In this study we demonstrate the successful deployment of a multirotor UAV (quadcopter) system with custom-made lightweight payloads for the compositional analysis and gas flux estimation of volcanic plumes. The various applications and their potential are presented and discussed in example studies at three volcanoes encompassing flight heights of 450 to 3300m and various states of volcanic activity. Field applications were performed at Stromboli volcano (Italy), Turrialba volcano (Costa Rica) and Masaya volcano (Nicaragua). Two in situ gas-measuring systems adapted for autonomous airborne measurements, based on electrochemical and optical detection principles, as well as an airborne sampling unit, are introduced. We show volcanic gas composition results including abundances of CO2, SO2 and halogen species. The new instrumental setups were compared with established instruments during ground-based measurements at Masaya volcano, which resulted in CO2 = SO2 ratios of 3.6 0.4. For total SO2 flux estimations a small differential optical absorption spectroscopy (DOAS) system measured SO2 column amounts on transversal flights below the plume at Turrialba volcano, giving 1776 1108 T d1 and 1616 1007 T d1 of SO2 during two traverses. At Stromboli volcano, elevated CO2 = SO2 ratios were observed at spatial and temporal proximity to explosions by airborne in situ measurements. Reactive bromine to sulfur ratios of 0.19 104 to 9.8 104 were measured in situ in the plume of Stromboli volcano, down wind of the vent.Published2441-24574V. Processi pre-eruttiviJCR Journa

Gas emission and composition measurements at two Andean volcanoes - Copahue and Peteroa

Copahue (37.856◦S, 71.159◦W, 2997 m a.s.l.) and Peteroa (35.240oS, 70.570oW, 3603 m a.s.l.) are active strato-volcanos, both located at the border between Argentina and Chile. Copahue volcano is situated on the rim of the large, about 2 Ma old Caviahue caldera. The eastern currently active summit crater hosts a cold melt water lake, a hyperacidic lake and a spattering mud pool (observation March 2018). The crater is surrounded by walls of phreatic debris and glacier ice. Peteroa volcano is part of the NNE-oriented Planchón-Peteroa-Azufre Volcanic Complex. The about 5 km wide caldera at the Peteroa summit is partially covered by glaciers and consists of four craters hosting acidic lakes and one scoria cinder cone. The activity of both volcanos is characterized by phreatic and phreactomagmatic eruptions. During February-March 2018, new emission flux and gas composition measurements at Peteroa and Copahue were undertaken. We performed measurements of SO2 fluxes with a scanning DOAS instrument. The SO2 flux atPeteroa was 188(±28) tSO2/d and the SO2 flux at Copahue was determined to 1294 ± 377 tSO2/d. Both values are similar to earlier reported SO2 fluxes on Peteroa and Copahue, respectively. Simultaneously to the SO2 fluxes, we determined CO2/SO2 ratio inside the plumes with a PITSA instrument by measuring at the crater rim of crater 4, the only significantly degassing crater at Peteroa as well as on the crater rim of Copahue. The CO2/SO2 ratio for Peteroa on all three measurement days varied only slightly between 1,44and 1,81 meaning that the CO2 flux of Peteroa plume was about 300(±72) tCO2/d.At Copahue, the CO2/SO2 ratio lies between around 1 and 60. The large scatter in the CO2/SO2 ratio of Copahue?s plume most likely originates from mixing of emissions from the closely located sources. We assign the lowest values of the CO2/SO2 ratio (CO2/SO2 = 1) to the plume from the spattering mud pool, which has therefore a CO2 flux of 1294 ± 377 tCO2/d. This is however only a lower limit to the CO2 flux of Copahue since the CO2emissions from e.g. the bubbling lake (where most of the SO2 might be scrubbed and therefore cannot be used for tracing plume CO2) are not taken into account.In addition, we evaluated the DOAS spectra for halogen species. We could not detect any BrO or OClO above ourcolumn density detection limits of 2e13 molec cm-2, corresponding to 57 ppt and 8 ppt for Copahue and Peteroa, respectively.Furthermore, a comparison between soil and plume emission was carried out for the first time at Peteroa. This comparison leads to the result that the major emission of CO2 is focused on a ?point source? ? the lake inside crater 4. With the current data available from Peteroa, only about 2 % of the total calculated CO2 output are degassed by diffusive soil degassing in the crater region. Certainly, further studies in the surroundings are still necessary to assure no missing emission source on the flank of the volcano.Fil: Bobrowski, Nicole. Instituto Max Planck Institut für Chemische Okologie; AlemaniaFil: Kuhn, Jonas. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Lamberti, María Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Agusto, Mariano Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: García, Sebastian. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Velasquez, Gabriela. Observatorio Volcanologico de los Andes del Sur; ChileFil: Bucarey, Claudia. Observatorio Volcanologico de los Andes del Sur; ChileFil: Valderrama, Oscar. Observatorio Volcanologico de los Andes del Sur; ChileFil: Tirpitz, Lucas. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Platt., Ulrich. Johannes Gutenberg Universitat Mainz; AlemaniaEGU General AssemblyVienaAustriaEuropean Geosciences Unio

Non-dispersive UV Absorption Spectroscopy: A Promising New Approach for in-situ Detection of Sulfur Dioxide

A new type of instrument for in-situ detection of volcanic sulfur dioxide is presented on the basis of non-dispersive UV absorption spectroscopy. It is a promising alternative to presently used compact and low-cost SO2 monitoring techniques, over which it has a series of advantages, including an inherent calibration, fast response times (&lt; 2 s to reach 90 % of the applied concentration), a measurement range spanning about 5 orders of magnitude and small, well-known cross sensitivities to other gases. Compactness, cost-efficiency and detection limit (&lt; 1 ppm, few ppb under favorable conditions) are comparable to other presently used in-situ instruments. Our instrument prototype has been extensively tested in comparison studies with established methods. In autumn 2015, diverse volcanic applications were investigated such as fumarole sampling, proximal plume measurements and airborne measurements several kilometers downwind from the vent on Mt. Etna and White Island. General capabilities and limitations of the measurement principle are discussed, considering different instrument configurations and future applications

Measurement report: MAX-DOAS measurements characterise Central London ozone pollution episodes during 2022 heatwaves

Heatwaves are a substantial health threat in the UK, exacerbated by co-occurrence of ozone pollution episodes. Here we report on the first use of retrieved vertical profiles of nitrogen dioxide (NO2) and formaldehyde (HCHO) over Central London from a newly installed multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument coincident with two of three heatwaves for the hottest summer on record. We evaluate space-based sensor observations routinely used to quantify temporal changes in air pollution and precursor emissions over London. Collocated daily mean tropospheric column densities from the high-spatial-resolution space-based TROPOspheric Monitoring Instrument (TROPOMI) and MAX-DOAS, after accounting for differences in vertical sensitivities, are temporally consistent for NO2 and HCHO (both R = 0.71). TROPOMI NO2 is 27 %–31 % less than MAX-DOAS NO2, as expected from horizontal dilution of NO2 by TROPOMI pixels in polluted cities. TROPOMI HCHO is 20 % more than MAX-DOAS HCHO, greater than differences in past validation studies but within the range of systematic errors in the MAX-DOAS retrieval. The MAX-DOAS near-surface (0–110 m) retrievals have similar day-to-day and hourly variability to the surface sites for comparison of NO2 (R ≥ 0.7) and for MAX-DOAS HCHO versus surface site isoprene (R ≥ 0.7) that oxidises to HCHO in prompt and high yields. Daytime ozone production, diagnosed with MAX-DOAS HCHO-to-NO2 tropospheric vertical column ratios, is mostly limited by availability of volatile organic compounds (VOCs), except on heatwave days. Temperature-dependent biogenic VOC emissions of isoprene increase exponentially, resulting in ozone concentrations that exceed the regulatory standard for ozone and cause non-compliance at urban background sites in Central London. Locations in Central London heavily influenced by traffic remain in compliance, but this is likely to change with stricter controls on vehicle emissions of NOx and higher likelihood of heatwave frequency, severity, and persistence due to anthropogenic climate change.</p

Remote sensing of volcanic CO2, HF, HCl, SO2, and BrO in the downwind plume of Mt. Etna

Remote sensing of the gaseous composition of non-eruptive, passively degassing volcanic plumes can be a tool to gain insight into volcano interior processes. Here, we report on a field study in September 2015 that demonstrates the feasibility of remotely measuring the volcanic enhancements of carbon dioxide (CO2), hydrogen fluoride (HF), hydrogen chloride (HCl), sulfur dioxide (SO2), and bromine monoxide (BrO) in the downwind plume of Mt. Etna using portable and rugged spectroscopic instrumentation. To this end, we operated the Fourier transform spectrometer EM27/SUN for the shortwave-infrared (SWIR) spectral range together with a co-mounted UV spectrometer on a mobile platform in direct-sun view at 5 to 10 km distance from the summit craters. The 3 days reported here cover several plume traverses and a sunrise measurement. For all days, intra-plume HF, HCl, SO2, and BrO vertical column densities (VCDs) were reliably measured exceeding 5 x 10(16), 2 x 10(17), 5 x 10(17), and 1 x 10(14) molec cm(2), with an estimated precision of 2.2 x 10(15), 1.3 x 10(16), 3.6 x 10(16), and 1.3 x 10(13) molec cm(2), respectively. Given that CO2, unlike the other measured gases, has a large and wellmixed atmospheric background, derivation of volcanic CO2 VCD enhancements (Delta CO2) required compensating for changes in altitude of the observing platform and for background concentration variability. The first challenge was met by simultaneously measuring the overhead oxygen (O-2) columns and assuming covariation of O-2 and CO2 with altitude. The atmospheric CO2 background was found by identifying background soundings via the coemitted volcanic gases. The inferred Delta CO2 occasionally exceeded 2 x 10(19) molec cm(-2) with an estimated precision of 3.7 x 10(18) molec cm(-2) given typical atmospheric background VCDs of 7 to 8 x 10(21) molec cm(-2). While the correlations of Delta CO2 with the other measured volcanic gases confirm the detection of volcanic CO2 enhancements, correlations were found of variable significance (R-2 ranging between 0.88 and 0.00). The intra-plume VCD ratios Delta CO2/SO2, SO2/HF, SO2/HCl, and SO2/BrO were in the range 7.1 to 35.4, 5.02 to 21.2, 1.54 to 3.43, and 2.9 x 10(3) to 12.5 x 10(3), respectively, showing pronounced day-to-day and intra-day variability

Prevalence of inflammatory bowel disease among coeliac disease patients in a Hungarian coeliac centre

BACKGROUND: Celiac disease, Crohn disease and ulcerative colitis are inflammatory disorders of the gastrointestinal tract with some common genetic, immunological and environmental factors involved in their pathogenesis. Several research shown that patients with celiac disease have increased risk of developing inflammatory bowel disease when compared with that of the general population. The aim of this study is to determine the prevalence of inflammatory bowel disease in our celiac patient cohort over a 15-year-long study period. METHODS: To diagnose celiac disease, serological tests were used, and duodenal biopsy samples were taken to determine the degree of mucosal injury. To set up the diagnosis of inflammatory bowel disease, clinical parameters, imaging techniques, colonoscopy histology were applied. DEXA for measuring bone mineral density was performed on every patient. RESULTS: In our material, 8/245 (3,2 %) coeliac disease patients presented inflammatory bowel disease (four males, mean age 37, range 22-67), 6/8 Crohn's disease, and 2/8 ulcerative colitis. In 7/8 patients the diagnosis of coeliac disease was made first and inflammatory bowel disease was identified during follow-up. The average time period during the set-up of the two diagnosis was 10,7 years. Coeliac disease serology was positive in all cases. The distribution of histology results according to Marsh classification: 1/8 M1, 2/8 M2, 3/8 M3a, 2/8 M3b. The distribution according to the Montreal classification: 4/6 Crohn's disease patients are B1, 2/6 Crohn's disease patients are B2, 2/2 ulcerative colitis patients are S2. Normal bone mineral density was detected in 2/8 case, osteopenia in 4/8 and osteoporosis in 2/8 patients. CONCLUSIONS: Within our cohort of patients with coeliac disease, inflammatory bowel disease was significantly more common (3,2 %) than in the general population

Inter-comparison of MAX-DOAS measurements of tropospheric HONO slant column densities and vertical profiles during the CINDI-2 campaign

We present the inter-comparison of delta slant column densities (SCDs) and vertical profiles of nitrous acid (HONO) derived from measurements of different multi-axis differential optical absorption spectroscopy (MAX-DOAS) instruments and using different inversion algorithms during the Second Cabauw Inter-comparison campaign for Nitrogen Dioxide measuring Instruments (CINDI-2) in September 2016 at Cabauw, the Netherlands (51.97∘ N, 4.93∘ E). The HONO vertical profiles, vertical column densities (VCDs), and near-surface volume mixing ratios are compared between different MAX-DOAS instruments and profile inversion algorithms for the first time. Systematic and random discrepancies of the HONO results are derived from the comparisons of all data sets against their median values. Systematic discrepancies of HONO delta SCDs are observed in the range of ±0.3×1015 molec. cm−2, which is half of the typical random discrepancy of 0.6×1015 molec. cm−2. For a typical high HONO delta SCD of 2×1015 molec. cm−2, the relative systematic and random discrepancies are about 15 % and 30 %, respectively. The inter-comparison of HONO profiles shows that both systematic and random discrepancies of HONO VCDs and near-surface volume mixing ratios (VMRs) are mostly in the range of ∼±0.5×1014 molec. cm−2 and ∼±0.1 ppb (typically ∼20 %). Further we find that the discrepancies of the retrieved HONO profiles are dominated by discrepancies of the HONO delta SCDs. The profile retrievals only contribute to the discrepancies of the HONO profiles by ∼5 %. However, some data sets with substantially larger discrepancies than the typical values indicate that inappropriate implementations of profile inversion algorithms and configurations of radiative transfer models in the profile retrievals can also be an important uncertainty source. In addition, estimations of measurement uncertainties of HONO dSCDs, which can significantly impact profile retrievals using the optimal estimation method, need to consider not only DOAS fit errors, but also atmospheric variability, especially for an instrument with a DOAS fit error lower than ∼3×1014 molec. cm−2. The MAX-DOAS results during the CINDI-2 campaign indicate that the peak HONO levels (e.g. near-surface VMRs of ∼0.4 ppb) often appeared in the early morning and below 0.2 km. The near-surface VMRs retrieved from the MAX-DOAS observations are compared with those measured using a co-located long-path DOAS instrument. The systematic differences are smaller than 0.15 and 0.07 ppb during early morning and around noon, respectively. Since true HONO values at high altitudes are not known in the absence of real measurements, in order to evaluate the abilities of profile inversion algorithms to respond to different HONO profile shapes, we performed sensitivity studies using synthetic HONO delta SCDs simulated by a radiative transfer model with assumed HONO profiles. The tests indicate that the profile inversion algorithms based on the optimal estimation method with proper configurations can reproduce the different HONO profile shapes well. Therefore we conclude that the features of HONO accumulated near the surface derived from MAX-DOAS measurements are expected to represent the ambient HONO profiles well