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Methane clumped isotope signatures of abiogenesis may be diagnostic of the origin of methane on Earth and other planetary bodies. We performed synthesis of abiogenic methane in hydrothermal conditions between 130 and 300°C and determined δ13C, δD, Δ13CH3D, and Δ12CH2D2. The experiments were performed by heating water in the presence of Fe0 powder and CO. The reduction of water on metallic iron led to the formation of H2. CO was reacted with both H2 and H2O, generating both CH4 and CO2. Methane δ13C values are isotopically depleted by ∼25‰ relative to the CO starting material. This is consistent with carbon isotopic equilibrium between methane, carbon monoxide and carbon dioxide in our experiments. In contrast, D/H ratios are inconsistent with equilibrium isotopic fractionation, as illustrated by δD values of methane fractionated by ∼500‰ relative to starting H2O. This suggests that under our experimental conditions, hydrogen additions to carbon may be governed by kinetics. Δ13CH3D values track experimental temperature, with values between +1.5‰ and +5.0‰ for most samples. In contrast, Δ12CH2D2 values are displaced from equilibrium. We find exclusively negative Δ12CH2D2 values, showing deficits down to 40‰ relative to thermodynamic equilibrium. We interpret the data as evidence for distinct, kinetically induced D/H pools contributing to methane assembly, that is, a combinatorial effect. The cumulative D/H fractionations associated with CO hydrogenation explain the direction and magnitude of Δ12CH2D2 values during abiotic methane formation. We suggest that near equilibrium Δ13CH3D with negative Δ12CH2D2 signatures will help identify methane formed abiotically in nature. Plain Language Summary: Methane is observed in various environmental settings on Earth, including but not limited to, hydrothermal fluids and sedimentary systems. It is also found on other worlds, as it was reported to occur on Mars, in Enceladus's geysers, and as of recently, in an exoplanet's atmosphere. Methane may be formed by life or by non‐biological processes, so the presence of methane alone on another world is not enough to declare a planet habitable. Geochemists have built methods to tell biogenic from abiotic methane, which ought to be useful for the identification of life‐derived methane on another planet. Those techniques are crucial but complex, based on integrated studies combining molecular and isotopic compositions of methane and associated gases. Here, we report on whether abiotic methane shows a unique signature for 13CH3D and 12CH2D2, the mass‐18 isotopologues of methane. We performed synthesis of abiotic methane in the laboratory and determined its composition. We observe unique signatures for methane clumping, where 12CH2D2 disequilibrium is associated with equilibrium 13CH3D abundances. We suggest that near equilibrium Δ13CH3D with negative Δ12CH2D2 signatures will help identify methane formed abiotically on Earth and on other worlds. Key Points: Synthesis of abiotic methane in the laboratory via a controlled Fischer‐Tropsch process under hydrothermal conditions carbon isotope equilibrium and hydrogen isotope disequilibrium during methane assembly13CH3D equilibration associated with substantial 12CH2D2 disequilibrium. Abiosignatures identified with combined 13CH3D and 12CH2D2 [ABSTRACT FROM AUTHOR]

Background: Anti‐tumour necrosis factor alpha (anti‐TNF) agents are a highly effective treatment for inflammatory bowel disease (IBD). Skin lesions, including psoriasiform, eczematous and lupoid eruptions, may paradoxically result from anti‐TNF use and cause significant morbidity leading to discontinuation of therapy. There are no consensus guidelines on the management of these lesions. Aims: This systematic review considers the existing evidence regarding cutaneous complications of anti‐TNF therapy in IBD and the development of an algorithm for management. Methods: A systematic review was performed by searching Medline (Pubmed) and Embase for articles published from inception to January 2021. The following search terms were used 'anti‐tumour necrosis factor alpha', 'infliximab', 'adalimumab', 'certolizumab', 'golimumab', 'inflammatory bowel disease', 'Crohn disease', 'Ulcerative colitis', 'psoriasis', 'psoriasiform', 'dermatitis', 'lupus', 'skin lesion' and 'skin rash'. Reference lists of relevant studies were reviewed to identify additional suitable studies. Results: Thirty‐four studies were included in the review. Eczema can generally be managed with topical agents and the anti‐TNF can be continued, while the development of lupus requires immediate cessation of the anti‐TNF and consideration of alternative immunomodulators. Management of psoriasis and psoriasiform lesions may follow a step‐wise algorithm where topical treatments will be trialled in less severe cases, with recourse to an alternative anti‐TNF or a switch to an alternative class of biological agent. Conclusion: Assessment of anti‐TNF skin lesions should be performed in conjunction with a dermatologist and rheumatologist in complex cases. High‐quality prospective studies are needed to clarify the validity of these algorithms in the future. [ABSTRACT FROM AUTHOR]

Identification of methane origins remains a challenging work as current diagnostic signals are often not sufficient to resolve individual formation and post‐formation processes. To address such a knowledge gap in a tectonically active and fragmented terrain, samples from mud volcanoes, gas seeps, and springs distributed along structural features onshore and offshore of Taiwan were analyzed for their isotopic compositions of methane, nitrogen, helium, dissolved inorganic carbon, CO2, and water. Our analyses yielded Δ13CH3D and Δ12CH2D2 values ranging between +1.9‰ and +7.8‰ and between +3.0‰ and +19.9‰, respectively. A portion of the samples were characterized by values that represent the thermodynamic equilibrium at temperatures of 99°–260°C. These temperature estimates, together with the bulk isotopic compositions and local geothermal gradients (25°–30°C/km), suggest that methane was formed by thermal maturation of organic matter at depths of 2–9 km below the land surface and channeled upward along faults. Other samples were found to deviate from equilibrium by varying degrees. Considering the geological background, helium isotopic ratios, and nitrogen isotopologue compositions, and methanogens detected at some sites, these gases are either abiotic in origin or a mixture of microbial and thermogenic sources. Regardless of whether the equilibrium of methane isotopologues was reached, few sites hosted by sedimentary formations were characterized by mantle‐like helium signatures, indicating decoupled origins and potential degassing of helium from the relic igneous source. Overall, these results suggest the extraction of methane and other gases from multiple depths from strata fragmented by fault displacement in an active orogenic belt. Plain Language Summary: Mud volcanoes and gas seeps are distributed primarily in active tectonic regimes and represent the surface expression of subsurface fracture networks. They provide rapid access to probing subsurface characteristics for the generations of methane, other gases, and water. Identifying the exact mechanisms of methane formation remains a challenging work due to the lack of diagnostic signals with sufficient resolving power. This study employed a wide range of isotopic tools to constrain the origins of gases and water from mud volcanoes and seeps in Taiwan, where dual subductions and associated arc‐continent collision between the Philippine Sea and Eurasian plates have enabled the plumbing of gases and water in accordance with structure development and stratum deformation. Our results reveal a spectrum of geochemical characteristics that point to diverse formation mechanisms and conditions. In particular, deeply sourced thermogenic methane (from depths of 2–9 km) appears to constitute a major gas component at most sites, and is mixed by various degrees with abiotic methane pertinent to igneous bodies emplaced during subduction/collision, or microbial methane generated at shallow depths. Overall, the results address the temporal and spatial variations in gas origins prone to terrain fragmentation and dynamic structural control associated with mountain building. Key Points: Mud volcanoes and gas seeps provide rapid access to probing subsurface fluid characteristics in tectonically active regionsThermogenic methane constitutes a major component of hydrocarbons and forms at temperatures of 99°–260°CA wide spectrum of geochemical characteristics indicates diverse formation mechanisms and conditions that constrain gas and water origins [ABSTRACT FROM AUTHOR]

Background: Colorectal adenocarcinoma is an important and preventable complication of inflammatory bowel disease (IBD). A previous case series suggested mental health issues and poor engagement in care as novel risk factors. Aims: To confirm the role of patient engagement in care in the development of neoplasia using a case‐control methodology. Methods: Patients in a single referral centre from 2007 to 2017 with colorectal adenocarcinoma, high‐grade dysplasia or multifocal low‐grade dysplasia were included as neoplasia cases. Each case was assigned up to three matched controls (matched for age, gender, underlying disease, IBD type and phenotype and disease duration). Novel and known risk factors were compared between groups. Results: Thirty‐two cases with 88 matched controls were included. Patients with neoplasia were more likely to have poor adherence to, or engagement with, care (odds ratio (OR) 4.79). They were also more likely to have chronic use of opioids (OR 3.86) and long‐term prednisolone (OR 2.97). Of note, no difference was found in measures of socioeconomic disadvantage, reflecting equitable access to healthcare in the public institution where the care was studied. As previously shown, patients with neoplasia had multiple markers of increased cumulative burden of inflammation, including more IBD‐related hospital admissions, elevated inflammatory markers and severe inflammation at colonoscopy. Conclusions: This study confirms poor adherence or engagement with care as a new risk factor for colorectal adenocarcinoma in patients with IBD; identifying a vulnerable group whom clinicians should endeavour to engage in order to avoid this catastrophic complication. [ABSTRACT FROM AUTHOR]

Background: Emergency general surgery is an emerging public health issue globally, with substantial healthcare burden. Interhospital transfer of critically unwell surgical patients has been the mainstay of bridging gaps in surgical coverage in regional and rural locations, despite evidence of greater morbidity and mortality. Delays in transfer invariably occurs and compounds the situation. Our aim was to examine the factors influencing interhospital transfer delays in emergency general surgical patients. Methods: A systematic search of PubMED and EmBase, was performed by two researchers from 2020 to 23rd Feb 2021, for English articles related to interhospital transfer delays in emergency general surgical patients, with an age of >16. Articles were critically appraised and data were extracted into a pre‐specified data extraction form. No data was suitable for statistical analysis and a narrative synthesis was performed instead. Results: Six relevant articles were identified from the search. All studies were retrospective cohort studies with moderate to high risk of bias. Lack of consultant surgeon input, after hours transfer, need for intensive care bed and poor transfer documentation may have a role in interhospital transfer delays. Patients with public health insurance, multiple comorbidities and non‐emergency medical conditions experience longer transfer request time and may be at risk of precipitating interhospital transfer delays. Transfer delays are seen in transfers over longer distances. Conclusion: There is a paucity of knowledge on what and how factors influence interhospital transfer delays in emergency general surgical patients. Well‐designed prospective cohort studies are required to bridge this knowledge gap. [ABSTRACT FROM AUTHOR]

Background: Interhospital transfers in Australia facilitate access to acute surgical services, however transfer delays can occur. The aims of this study were to examine Australian mortality audit data on acute surgical patients who were transferred after presenting with a surgical emergency, and to identify modifiable predictors of transfer delay. Methods: Surgical admissions between 1 January 2001 and 18 August 2020 were retrospectively extracted from the Australian and New Zealand Audit of Surgical Mortality database. Relevant factors and themes of interest were collated. Results were presented as odds ratios (OR) and 95% confidence intervals (CI), with statistical significance defined as P <0.05. Results: After exclusion, a final 8270 cases were analysed. Non‐modifiable predictors identified were female gender (OR 1.34, 95% CI 1.05–1.70, P = 0.0184), comorbidities (OR 1.50, 95% CI 1.40–161, P <0.0001) and major non‐trauma non‐vascular specialty (OR 1.54 to 7.77, depending on specialty, P < 0.05). Modifiable predictors were inadequate clinical assessment (OR 49.48, 95% CI 32.91–74.38, P <0.0001), poor communication (OR 6.62, 95% CI 3.70–11.85, P <0.0001) and multiple transfers (OR 6.30, OR 95% 4.31–9.21, P <0.0001). Age, lack of bed and after‐hours transfer did not predict transfer delays. Metropolitan transfers was protective against transfer delays (OR 0.64, 95% CI 0.47–0.86, P = 0.0035). Conclusion: In the view of the receiving surgeon or assessor, all transfer delays potentially contributed to patient deaths, and may have been preventable. Strategies directed at modifiable factors could minimize delays. Increased surgical services in non‐metropolitan regions could reduce need for transfer. Prospective data is required to examine if the same predictors are observed in surgical patients who survive. [ABSTRACT FROM AUTHOR]

The trapped melt fractional crystallization model for the IIIAB iron meteorites put forward by J. T. Wasson two decades prior is revisited. The basic precepts upon which the model was based remain true, and the model can be implemented using Ir and Au solid/liquid distribution coefficients that are broadly consistent with experimental data. For this reason, the difference between the Wasson model and some more recent trapped melt models lies mainly with inferences about the S concentrations of the core of the IIIAB iron meteorite parent body. For the Wasson model, S bulk concentrations of about 2 wt% are implied. For the more recent model, much greater concentrations of between about 12–15 wt% are indicated. The two different trapped melt models profoundly influence the interpretation of high δ57Fe values relative to chondrites in the IIIAB irons. The Wasson model suggests that there should be more variations in δ57Fe than are observed among these meteorites, while the more recent trapped melt model relies on the crystallization of FeS from the trapped melt to raise the δ57Fe of the latter, thus minimizing the variability. The interpretation of Fe isotope ratios in the IIIAB meteorites therefore depends critically on the S concentration of the parent body core. [ABSTRACT FROM AUTHOR]

Background: The Lyell McEwin Hospital entered into a public–private collaborative agreement in 2019 in order to access Da Vinci® Xi Surgical Systems (Intuitive Surgical, Sunnyvale, CA, USA) in private hospitals. This study aimed to examine the costs associated with usage of robot surgical systems under the agreement, and the potential for acquisition in the public hospital. Methods: Retrospective data on robotic-assisted and equivalent operations performed between 1 May 2019 and 30 April 2020 were collected and formed subsequent model inputs. Cost data were from hospital records and the local Da Vinci® Xi distributor. Clinical workflow of operations was simulated with a decision-analytic model, with output being costs incurred. The model’s base case scenario assumed 5% of cases were robotically assisted. Results: A total of 35 robotic-assisted, 101 laparoscopic and 34 open operations were performed. Patients were predominantly male and overweight with multiple comorbidities. Length of stay and duration of operation were associated with increased costs (p < 0.001, r² 0.72). In the base case scenario, there was a cost of AU$26 424 per patient, with an open conversion rate of 11%. Increasing robotic-assisted case percentage resulted in reduced cost, open conversion rates and length of stay. Extrapolation of cost model data indicated if 50% were robotic-assisted cases, then the initial capital investment (assumed at AU$4 000 000) could be recovered in 10 years. Conclusion: Our model highlights potential advantages of performing greater numbers of robotic-assisted operations in a collaborative environment. Cost-effective analysis with prospective data could evaluate if these results are translatable and potentially support acquisition of robotic systems in the public sector. [ABSTRACT FROM AUTHOR]

In hyperalkaline (pH>10) fluids that have participated in low‐temperature (<150°C) serpentinization reactions, the dominant form of C is often methane (CH4), but the origin of this CH4 is uncertain. To assess CH4 origin in serpentinite aquifers within the Samail Ophiolite, Oman, we determined fluid chemical compositions, analyzed taxonomic profiles of fluid‐hosted microbial communities, and measured isotopic compositions of hydrocarbon gases. We found that 16S rRNA gene sequences affiliated with methanogens were widespread in the aquifer. We measured clumped isotopologue (CH313D and CH212D2) relative abundances less than equilibrium, consistent with substantial microbial CH4 production. Furthermore, we observed an inverse relationship between dissolved inorganic C concentrations and δ13CCH4 across fluids bearing microbiological evidence of methanogenic activity, suggesting that the apparent C isotope effect of microbial methanogenesis is modulated by C availability. An additional source of CH4 is evidenced by the presence of CH4‐bearing fluid inclusions in the Samail Ophiolite and our measurement of high δ13C values of ethane and propane, which are similar to those reported in studies of CH4‐rich inclusions in rocks from the oceanic lithosphere. In addition, we observed 16S rRNA gene sequences affiliated with aerobic methanotrophs and, in lower abundance, anaerobic methanotrophs, indicating that microbial consumption of CH4 in the ophiolite may further enrich CH4 in 13C. We conclude that substantial microbial CH4 is produced under varying degrees of C limitation and mixes with abiotic CH4 released from fluid inclusions. This study lends insight into the functioning of microbial ecosystems supported by water/rock reactions. Plain Language Summary: Mantle rocks from beneath Earth's crust can be thrust to the surface, where they are exposed to rain and air containing carbon dioxide (CO2). The groundwaters that become stored in these rocks often contain methane (CH4, a major component of "natural gas"), which can be formed from carbon dioxide in the subsurface. To investigate these methane‐forming processes, we sampled water, gas, and suspended particles from groundwaters using wells previously drilled into the rocks. The particles contained microbes with the genetic ability to produce methane. We also precisely measured the amounts of combinations of C and H atoms of different masses (isotopes) in the natural gas to determine how it was formed. The results of these measurements suggest that microbes could actively produce a considerable amount of the methane, which mixes with methane from another source that was formed by non‐biological processes, possibly long ago under different conditions than today's. Rocks like those studied here are widespread in the Solar System, so our finding that microbes live and produce methane in these rocks could help guide the search for life beyond Earth. Key Points: 16S rRNA gene sequences affiliated with methanogens and CH4 clumped isotopologue compositions suggest substantial microbial CH4 productionA second CH4 source, release of CH4 from fluid inclusions, is indicated by 13C‐enriched ethane and propaneC availability may influence the apparent C isotope effect of microbial methanogenesis [ABSTRACT FROM AUTHOR]

Background and Aims: Gastrointestinal (GI) adenocarcinoma, especially colorectal cancer (CRC), is a devastating complication of inflammatory bowel disease (IBD). We sought to examine the role of chronic inflammation and other possible predictors of the development of CRC, as well as assess as yet unexamined factors such as psychological comorbidity and engagement in care. Methods: This study included all patients involved in a tertiary hospital IBD service diagnosed with CRC between 2007 and 2017. Reports from histological specimens were assessed, and all those with adenocarcinoma, high‐grade dysplasia (HGD), or multifocal low‐grade dysplasia (LGD) originating within IBD‐affected mucosa were included in the study. Results: A total of 32 patients were included in the study (17 with adenocarcinoma and 15 with HGD/multifocal LGD). The majority had a duration of disease >20 years. Eleven patients (34%, CI 20–52%) had previous disease‐related surgery, and 16 (50%, CI 34–66%) had multiple previous disease‐related admissions. Thirteen patients (62%, CI 41–79%) had >50% of CRP results higher than 8 mg/L. Psychiatric comorbidities were common, with 19 patients (59%, CI 42–74%) having a psychiatric comorbidity or poor engagement in treatment. Conclusion: In this cohort, we have highlighted poor engagement, hesitation to up‐titrate therapy when indicated, and psychological comorbidities as likely contributors to poor disease control and development of GI adenocarcinoma. Based on our data, these easily identifiable clinical care factors should not be overlooked when addressing IBD‐related GI malignancy prevention. Additional research is required to assess a direct causal relationship, but this study would support the incorporation of psychology services into IBD clinics. [ABSTRACT FROM AUTHOR]

Background: Appendicectomy is a safe surgical procedure with minimal risks. Low mortality rates (0.04–0.24%) have been reported from a number of countries. Appendicectomy mortality rates have not been reported in Australia in recent years. The aim of the study was to conduct an appendicectomy mortality audit, to identify clinical management issues and to calculate the mortality rate of appendicectomy in Australia. Methods: This study analysed data from a peer review of appendicectomy deaths in Australian hospitals of all states and territories, from 2006 to 2017. Additional procedural data were obtained from the Australian Institute of Health and Welfare for the calculation of mortality rates. Results: The final analysis included 82 patients of whom 62 were elderly (age >65 years) with 47 males and 35 females. Two or more comorbidities were present in 68 patients. Open operation was performed in 62 patients, with complicated appendicitis found in 50 cases. The majority of management issues were non‐surgical. Of the 16 surgical management issues identified, 11 issues occurred post‐operatively in the elderly, which were potentially preventable. The overall mortality was 0.02% with 0.01% in the young (age <65 years) and 0.20% in the elderly. Conclusion: Australia's appendicectomy mortality rate was very low and comparable to international figures. Surgical management of appendicectomy was satisfactory in general. However, post‐operative care in the elderly was found to be poor at times, with room for improvement. Further research is needed whether improvements in post‐operative care could alter the clinical course to death in the elderly. [ABSTRACT FROM AUTHOR]

Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC3). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70–80% are ureilites (achondrites) and 20–30% are various types of chondrites. Asteroid 2008 TC3 was a heterogeneous breccia that disintegrated in the atmosphere, with its clasts landing on Earth as individual stones and most of its mass lost. We describe AhS 91A and AhS 671, which are the first AhS stones to show contacts between ureilitic and chondritic materials and provide direct information about the structure and composition of asteroid 2008 TC3. AhS 91A and AhS 671 are friable breccias, consisting of a C1 lithology that encloses rounded to angular clasts (<10 μm to 3 mm) of olivine, pyroxenes, plagioclase, graphite, and metal‐sulfide, as well as chondrules (~130–600 μm) and chondrule fragments. The C1 material consists of fine‐grained phyllosilicates (serpentine and saponite) and amorphous material, magnetite, breunnerite, dolomite, fayalitic olivine (Fo 28‐42), an unidentified Ca‐rich silicate phase, Fe,Ni sulfides, and minor Ca‐phosphate and ilmenite. It has similarities to CI1 but shows evidence of heterogeneous thermal metamorphism. Its bulk oxygen isotope composition (δ18O = 13.53‰, δ17O = 8.93‰) is unlike that of any known chondrite, but similar to compositions of several CC‐like clasts in typical polymict ureilites. Its Cr isotope composition is unlike that of any known meteorite. The enclosed clasts and chondrules do not belong to the C1 lithology. The olivine (Fo 75‐88), pyroxenes (pigeonite of Wo ~10 and orthopyroxene of Wo ~4.6), plagioclase, graphite, and some metal‐sulfide are ureilitic, based on mineral compositions, textures, and oxygen isotope compositions, and represent at least six distinct ureilitic lithologies. The chondrules are probably derived from type 3 OC and/or CC, based on mineral and oxygen isotope compositions. Some of the metal‐sulfide clasts are derived from EC. AhS 91A and AhS 671 are plausible representatives of the bulk of the asteroid that was lost. Reflectance spectra of AhS 91A are dark (reflectance ~0.04–0.05) and relatively featureless in VNIR, and have an ~2.7 μm absorption band due to OH− in phyllosilicates. Spectral modeling, using mixtures of laboratory VNIR reflectance spectra of AhS stones to fit the F‐type spectrum of the asteroid, suggests that 2008 TC3 consisted mainly of ureilitic and AhS 91A‐like materials, with as much as 40–70% of the latter, and <10% of OC, EC, and other meteorite types. The bulk density of AhS 91A (2.35 ± 0.05 g cm−3) is lower than bulk densities of other AhS stones, and closer to estimates for the asteroid (~1.7–2.2 g cm−3). Its porosity (36%) is near the low end of estimates for the asteroid (33–50%), suggesting significant macroporosity. The textures of AhS 91A and AhS 671 (finely comminuted clasts of disparate materials intimately mixed) support formation of 2008 TC3 in a regolith environment. AhS 91A and AhS 671 could represent a volume of regolith formed when a CC‐like body impacted into already well‐gardened ureilitic + impactor‐derived debris. AhS 91A bulk samples do not show a solar wind component, so they represent subsurface layers. AhS 91A has a lower cosmic ray exposure (CRE) age (~5–9 Ma) than previously studied AhS stones (11–22 Ma). The spread in CRE ages argues for irradiation in a regolith environment. AhS 91A and AhS 671 show that ureilitic asteroids could have detectable ~2.7 μm absorption bands. [ABSTRACT FROM AUTHOR]

Background and Aim: Small bowel mucosal biopsies (SBBx) are routinely performed to investigate unexplained anemia; however, previous studies have demonstrated a low yield in diagnosing celiac disease. Our aim was to determine the yield of routine SBBx in a large cohort of patients who underwent gastroscopy for the investigation of anemia. Methods: Data from consecutive patients who underwent gastroscopy for the investigation of anemia in a tertiary hospital, from January 2008–December 2011, were prospectively collected. Measured outcomes were the prevalence of celiac disease, the yield of duodenal biopsies, and the correlation between celiac serology and diagnosis. Results: Over 4 years, 987 patients (385 M:602 F; 48.27 ± 15.89 years) underwent endoscopy for anemia, of which 534 (54.1%) had proven iron deficiency anemia (IDA). Abnormal SBBx consistent with celiac disease were found in 2% (22/987), with a higher prevalence in females (3.2%, n = 19 vs 0.8%, n = 3 in males) and in those with IDA (3.6%, n = 19 vs 0.7%, n = 3 in non‐IDA). Macroscopic endoscopic abnormalities were present in 86% (19/22) of patients with celiac disease. Of the 178 patients who had celiac serology, tissue transglutaminase antibody had the highest sensitivity (80%) and specificity (99%). Combined serology had a sensitivity of 85.7%. Conclusion: Only 2% of patients with unexplained anemia had abnormal SBBx consistent with celiac disease and even fewer patients in non‐IDA. Given the availability and high sensitivity of celiac serology and macroscopic changes on endoscopy, SBBx should not be routine during endoscopy but should be limited to those with positive celiac serology, abnormal endoscopic appearance, or females with IDA. Small bowel biopsies are regularly performed during the endoscopic investigation of anemia. Only 2% of patients with unexplained anemia in our study had abnormal small bowel biopsies consistent with celiac disease, and even fewer in anemia without iron deficiency. Given the availability and high sensitivity of celiac serology and macroscopic changes on endoscopy, small bowel biopsy should not be routine during endoscopy, but limited to those with positive celiac serology, abnormal endoscopic appearance or females with iron deficiency anemia (IDA). [ABSTRACT FROM AUTHOR]

We present a theoretical model to investigate the potential of 13CH3D and 12CH2D2, the doubly substituted mass-18 isotopologues of methane, as tools for tracking atmospheric methane sources and sinks. We use electronic structure methods to estimate kinetic isotope fractionations associated with the major sink reactions of methane in air (reactions with OH and Cl radicals) and combine literature data with reconnaissance measurements of the relative abundances of 13CH3D and 12CH2D2 to estimate the compositions of the largest atmospheric sources. This model atmospheric budget is investigated with a simplified box model in which we explore both steady state and dynamical (nonsteady state) conditions triggered by changes in emission or sink fluxes. The steady state model predicts that sink reactions will generate a marked (>100‰) clumped isotope excess in atmospheric Δ12CH2D2 relative to the net source composition. 12CH2D2 measurements may thus be useful for tracing both atmospheric source and sink fluxes. The effect of sinks on Δ13CH3D is much less pronounced, indicating that 13CH3D in air will give a more focused picture of the source composition. [ABSTRACT FROM AUTHOR]

RATIONALE Rapid development of the CO2 'clumped-isotope' temperature proxy (Δ47) has involved both resource- and labor-intensive analytical methods. We report strategies for measuring Δ47 on a conventional mass spectrometer, with the usual CO2 set of three Faraday collectors while reducing the time devoted to standardization with temperature-equilibrated CO2. METHODS We measured Δ47 in CO2 on a mass spectrometer using only three Faraday cups by 'multicollector peak hopping', directing 46CO2+ and 47CO2+ ion beams into the Faraday cups normally used for m/z 44 and 45. Δ47 was calculated from the previously measured δ13C and δ18O values and we then measured 47CO2+/46CO2+. We invoke a protocol for correcting ion-beam intensities for secondary electrons to address common problems with compositional non-linearity and both long- and short-term measurement stability. RESULTS Our method eliminates the need for six Faraday cups for measuring Δ47, a possible advantage for many laboratories. In addition, by using a correction based on removing the effects of secondary electrons, we remove the Δ47 dependence on δ47CO2. As a result, our methods are robust against mass spectrometer operating conditions. CONCLUSIONS Δ47 can be precisely measured on mass spectrometers currently employed for measuring δ13C and δ18O values without significant resource investment. Accounting for ion scatter during measurements of CO2 results in improved external precision and long-term stability, while significantly increasing the machine time available for sample analysis. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Past medical history included morbid obesity, umbilical hernia and an Orbera Intragastric Balloon System (Apollo Endosurgery Inc., Austin, TX, USA) inserted 3 years prior. An abdominal computed tomography scan identified a radiodense structure positioned within a distal small bowel loop, with proximal small bowel obstruction (Fig. The Meckel's diverticulum is positioned to the left side of the photograph, with the deflated black intragastric balloon situated inside and extending out towards the right. gl To the authors' knowledge, this is the first report of a small bowel obstruction caused by intragastric balloon impacting inside a Meckel's diverticulum. [Extracted from the article]

The Villalbeto de la Peña meteorite that fell in 2004 in Spain was originally classified as a moderately shocked L6 ordinary chondrite. The recognition of fragments within the Villalbeto de la Peña meteorite clearly bears consequences for the previous classification of the rock. The oxygen isotope data clearly show that an exotic eye-catching, black, and plagioclase-(maskelynite)-rich clast is not of L chondrite heritage. Villalbeto de la Peña is, consequently, reclassified as a polymict chondritic breccia. The oxygen isotope data of the clast are more closely related to data for the winonaite Tierra Blanca and the anomalous silicate-bearing iron meteorite LEW 86211 than to the ordinary chondrite groups. The REE-pattern of the bulk inclusion indicates genetic similarities to those of differentiated rocks and their minerals (e.g., lunar anorthosites, eucritic, and winonaitic plagioclases) and points to an igneous origin. The An-content of the plagioclase within the inclusion is increasing from the fragment/host meteorite boundary (approximately An10) toward the interior of the clast (approximately An52). This is accompanied by a successive compositionally controlled transformation of plagioclase into maskelynite by shock. As found for plagioclase, compositions of individual spinels enclosed in plagioclase (maskelynite) also vary from the border toward the interior of the inclusion. In addition, huge variations in oxygen isotope composition were found correlating with distance into the object. The chemical and isotopical profiles observed in the fragment indicate postaccretionary metamorphism under the presence of a volatile phase. [ABSTRACT FROM AUTHOR]

A capstone mechanical engineering laboratory course is being implemented at the University of South Carolina that develops the student's abilities to analyze complex mechanical and thermal systems, to design experiments, and to develop their professional skills. The course is based upon an integrated sequence of laboratory experiments on a Legends-class racecar. This vehicle is chosen as the system of study because it provides opportunities for the students to apply the spectrum of their mechanical engineering knowledge. It's also exciting to the students. As the students progress through the series of experiments, they are increasingly involved in experimental design (selecting sensors, sensor locations and experimental operating conditions). The course culminates in a truly open-ended design of an experiment of their choosing. This course development project is supported by the National Science Foundation's Instrumentation and Laboratory Improvement Program, the NSF's Course, Curriculum and Laboratory Improvement Program, and the University of South Carolina. This paper describes the work in progress. [ABSTRACT FROM AUTHOR]

Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC3). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70–80% are ureilites (achondrites) and 20–30% are various types of chondrites. Asteroid 2008 TC3 was a heterogeneous breccia that disintegrated in the atmosphere, with its clasts landing on Earth as individual stones and most of its mass lost. We describe AhS 91A and AhS 671, which are the first AhS stones to show contacts between ureilitic and chondritic materials and provide direct information about the structure and composition of asteroid 2008 TC3. AhS 91A and AhS 671 are friable breccias, consisting of a C1 lithology that encloses rounded to angular clasts (<10 μm to 3 mm) of olivine, pyroxenes, plagioclase, graphite, and metal‐sulfide, as well as chondrules (~130–600 μm) and chondrule fragments. The C1 material consists of fine‐grained phyllosilicates (serpentine and saponite) and amorphous material, magnetite, breunnerite, dolomite, fayalitic olivine (Fo 28‐42), an unidentified Ca‐rich silicate phase, Fe,Ni sulfides, and minor Ca‐phosphate and ilmenite. It has similarities to CI1 but shows evidence of heterogeneous thermal metamorphism. Its bulk oxygen isotope composition (δ18O = 13.53‰, δ17O = 8.93‰) is unlike that of any known chondrite, but similar to compositions of several CC‐like clasts in typical polymict ureilites. Its Cr isotope composition is unlike that of any known meteorite. The enclosed clasts and chondrules do not belong to the C1 lithology. The olivine (Fo 75‐88), pyroxenes (pigeonite of Wo ~10 and orthopyroxene of Wo ~4.6), plagioclase, graphite, and some metal‐sulfide are ureilitic, based on mineral compositions, textures, and oxygen isotope compositions, and represent at least six distinct ureilitic lithologies. The chondrules are probably derived from type 3 OC and/or CC, based on mineral and oxygen isotope compositions. Some of the metal‐sulfide clasts are derived from EC. AhS 91A and AhS 671 are plausible representatives of the bulk of the asteroid that was lost. Reflectance spectra of AhS 91A are dark (reflectance ~0.04–0.05) and relatively featureless in VNIR, and have an ~2.7 μm absorption band due to OH− in phyllosilicates. Spectral modeling, using mixtures of laboratory VNIR reflectance spectra of AhS stones to fit the F‐type spectrum of the asteroid, suggests that 2008 TC3 consisted mainly of ureilitic and AhS 91A‐like materials, with as much as 40–70% of the latter, and <10% of OC, EC, and other meteorite types. The bulk density of AhS 91A (2.35 ± 0.05 g cm−3) is lower than bulk densities of other AhS stones, and closer to estimates for the asteroid (~1.7–2.2 g cm−3). Its porosity (36%) is near the low end of estimates for the asteroid (33–50%), suggesting significant macroporosity. The textures of AhS 91A and AhS 671 (finely comminuted clasts of disparate materials intimately mixed) support formation of 2008 TC3 in a regolith environment. AhS 91A and AhS 671 could represent a volume of regolith formed when a CC‐like body impacted into already well‐gardened ureilitic + impactor‐derived debris. AhS 91A bulk samples do not show a solar wind component, so they represent subsurface layers. AhS 91A has a lower cosmic ray exposure (CRE) age (~5–9 Ma) than previously studied AhS stones (11–22 Ma). The spread in CRE ages argues for irradiation in a regolith environment. AhS 91A and AhS 671 show that ureilitic asteroids could have detectable ~2.7 μm absorption bands. [ABSTRACT FROM AUTHOR]