Earth shaped by primordial H2 atmospheres.

Earth's water, intrinsic oxidation state and metal core density are fundamental chemical features of our planet. Studies of exoplanets provide a useful context for elucidating the source of these chemical traits. Planet formation and evolution models demonstrate that rocky exoplanets commonly formed with hydrogen-rich envelopes that were lost over time1. These findings suggest that Earth may also have formed from bodies with hydrogen-rich primary atmospheres. Here we use a self-consistent thermodynamic model to show that Earth's water, core density and overall oxidation state can all be sourced to equilibrium between hydrogen-rich primary atmospheres and underlying magma oceans in its progenitor planetary embryos. Water is produced from dry starting materials resembling enstatite chondrites as oxygen from magma oceans reacts with hydrogen. Hydrogen derived from the atmosphere enters the magma ocean and eventually the metal core at equilibrium, causing metal density deficits matching that of Earth. Oxidation of the silicate rocks from solar-like to Earth-like oxygen fugacities also ensues as silicon, along with hydrogen and oxygen, alloys with iron in the cores. Reaction with hydrogen atmospheres and metal-silicate equilibrium thus provides a simple explanation for fundamental features of Earth's geochemistry that is consistent with rocky planet formation across the Galaxy.

Synapse-type-specific competitive Hebbian learning forms functional recurrent networks.

Cortical networks exhibit complex stimulus-response patterns that are based on specific recurrent interactions between neurons. For example, the balance between excitatory and inhibitory currents has been identified as a central component of cortical computations. However, it remains unclear how the required synaptic connectivity can emerge in developing circuits where synapses between excitatory and inhibitory neurons are simultaneously plastic. Using theory and modeling, we propose that a wide range of cortical response properties can arise from a single plasticity paradigm that acts simultaneously at all excitatory and inhibitory connections-Hebbian learning that is stabilized by the synapse-type-specific competition for a limited supply of synaptic resources. In plastic recurrent circuits, this competition enables the formation and decorrelation of inhibition-balanced receptive fields. Networks develop an assembly structure with stronger synaptic connections between similarly tuned excitatory and inhibitory neurons and exhibit response normalization and orientation-specific center-surround suppression, reflecting the stimulus statistics during training. These results demonstrate how neurons can self-organize into functional networks and suggest an essential role for synapse-type-specific competitive learning in the development of cortical circuits.

Texture and Color Enhancement Imaging Improves Colonic Adenoma Detection: A Multicenter Randomized Controlled Trial.

The global burden of colorectal cancer is expected to increase more than 60% by 2030; however, compelling evidence now shows that the implementation of population screening programs in developed countries has led to a substantial reduction in incidence and mortality.1,2 Despite this, patients continue to develop preventable colorectal cancers, in part because of high rates of interval colon cancer diagnosed after screening or surveillance colonoscopies.3.

Poor engagement and adherence predict neoplasia in inflammatory bowel disease: a case-control study.

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.

Anti-tumour necrosis factor-induced skin rashes in inflammatory bowel disease: a systematic review and evidence-based management algorithm.

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.

Pathophysiology of Dysphagia in Eosinophilic Esophagitis: Causes, Consequences, and Management.

Eosinophilic esophagitis (EoE) is a leading cause of food bolus impaction in children and adults. The mechanism of dysphagia in EoE, particularly non-obstructive dysphagia, remains incompletely understood. While fibrostenotic processes appear to be critical in the development of dysphagia, somatosensory dysfunction and dysmotility also contribute. This review considers potential mechanisms of dysphagia and evaluates the utility of current and future treatment strategies in this context.

Laboratory Exposures from an Unsuspected Case of Human Infection with Brucella canis.

We report a case of human infection with a Brucella canis isolate in an adult in Canada who was receiving a biologic immunomodulating medication. We detail subsequent investigations, which showed that 17 clinical microbiology staff had high-risk exposures to the isolate, 1 of whom had a positive result for B. canis.

In Situ Quantification of Biological N2 Production Using Naturally Occurring 15N15N.

We describe an approach for determining biological N2 production in soils based on the proportions of naturally occurring 15N15N in N2. Laboratory incubation experiments reveal that biological N2 production, whether by denitrification or anaerobic ammonia oxidation, yields proportions of 15N15N in N2 that are within 1‰ of that predicted for a random distribution of 15N and 14N atoms. This relatively invariant isotopic signature contrasts with that of the atmosphere, which has 15N15N proportions in excess of the random distribution by 19.1 ± 0.1‰. Depth profiles of gases in agricultural soils from the Kellogg Biological Station Long-Term Ecological Research site show biological N2 accumulation that accounts for up to 1.6% of the soil N2. One-dimensional reaction-diffusion modeling of these soil profiles suggests that subsurface N2 pulses leading to surface emission rates as low as 0.3 mmol N2 m-2 d-1 can be detected with current analytical precision, decoupled from N2O production.

The First Samples from Almahata Sitta Showing Contacts Between Ureilitic and Chondritic Lithologies: Implications for the Structure and Composition of Asteroid 2008 TC3.

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/cm3) is lower than bulk densities of other AhS stones, and closer to estimates for the asteroid (~1.7-2.2 g/cm3). 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 (SW) component, so they represent sub-surface 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.

Effectiveness of a cap-assisted device in the endoscopic removal of food bolus obstruction from the esophagus.

BACKGROUND AND AIM: The use of a transparent cap has been found to be effective for retrieval of an esophageal foreign body. However, data on the use of a cap in food bolus obstruction (FBO) are limited. This study aims to assess the effectiveness of a cap-assisted technique compared with conventional techniques in removal of FBO. METHODS: All patients who underwent an endoscopy for boneless FBO between 2011 and 2016 were prospectively recruited. The measured outcomes were procedure time, success rate of food bolus (FB) extraction, rate of en bloc removal, procedure-related adverse events, and length of hospital stay (LOS) between the 2 groups. RESULTS: Of the 315 patients who had an endoscopy for FBO, 48 (15.2%) had spontaneous passage of FB and 267 (84.8%) had impacted FB. Sixty-eight (25%) patients had the "push" maneuver, and 199 (75%) patients had the "pull" maneuver to remove FB. Of those who had the "pull" maneuver, a cap was used for 93 and conventional device(s) for 106. The use of a cap was associated with a shorter procedural time (34.3 ± 8.0 minutes versus 43.3 ± 22.6 minutes, P = .003), a higher rate of en bloc removal (87.3% versus 22.8%, P < .001), a lower rate of adverse events (0/93 versus 7/106, P = .01), and a shorter LOS (1.0 ± 0.6 days versus 1.6 ± 1.4 days, P = .0017). CONCLUSION: The cap-assisted technique has been found to be effective and safe in removal of esophageal FBO. This technique was associated with a shorter procedural time and a reduced LOS compared with conventional techniques. However, these findings require further validation in a randomized control study.

Short time interval for condensation of high-temperature silicates in the solar accretion disk.

Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived (26)Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a (26)Al isochron with (26)Al/(27)Al = 1.2(±0.2) × 10(-5) for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule (26)Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial ((26)Al/(27)Al) ≥ 1.2 × 10(-5). In addition, mineral (26)Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule (26)Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate.

Early Solar System hydrothermal activity in chondritic asteroids on 1-10-year timescales.

Chondritic meteorites are considered the most primitive remnants of planetesimals from the early Solar System. As undifferentiated objects, they also display widespread evidence of water-rock interaction on the parent body. Understanding this history has implications for the formation of planetary bodies, the delivery of water to the inner Solar System, and the formation of prebiotic molecules. The timescales of water-rock reactions in these early objects, however, are largely unknown. Here, we report evidence for short-lived water-rock reactions in the highly metamorphosed ordinary chondrite breccia Villalbeto de la Peña (L6). An exotic clast (d = 2cm) has coexisting variations in feldspar composition and oxygen isotope ratios that can only result from hydrothermal conditions. The profiles were modeled at T = 800 °C and P(H(2)O) = 1 bar using modified grain-boundary diffusion parameters for oxygen self-diffusion and reaction rates of NaSiCa(-1)Al(-1) exchange in a fumarole. The geochemical data are consistent with hydrothermal activity on the parent body lasting only 1-10 y. This result has wide-ranging implications for the geological history of chondritic asteroids.

High-precision determination of ¹³C-¹8O bonds in CO2 using multicollector peak hopping.

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 (46)CO2(+) and (47)CO2(+) ion beams into the Faraday cups normally used for m/z 44 and 45. Δ47 was calculated from the previously measured δ(13) C and δ(18) O values and we then measured (47)CO2(+)/(46)CO2(+). 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 δ(47)CO2. 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 δ(13) C and δ(18) O 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.

Intraoperative complications of robotic-assisted extended totally extraperitoneal (eTEP) ventral hernia retromuscular repairs with mesh: a systematic literature review and narrative synthesis.

Minimally invasive extended totally extraperitoneal (eTEP) technique is revolutionising ventral hernia repairs. Robotic-assisted eTEP has been gaining popularity due to better visual clarity and greater dexterity provided by the robotic systems, compared to laparoscopy. Despite growing number of papers being published each year, so far, no study has explored intraoperative complications in robotic-assisted eTEP. The aim was to perform a systematic literature review on the incidence of intraoperative complications in robotic-assisted eTEP ventral hernia repairs. The study protocol was preregistered with PROSPERO, registration number CRD42023450072. Twelve categories of intraoperative complications were defined by the authors. A search of PubMed and Embase was conducted on 16/08/2023, for articles pertaining to robotic-assisted eTEP operations in ventral hernias in adults. Articles were critically appraised and data were extracted using predefined extraction templates. No data were suitable for statistical analysis and a narrative synthesis was performed instead. Ten studies fulfilled the inclusion criteria, of which four studies reported intraoperative complications. Of the 12 categories of intraoperative complications, only 5 were reported. Three studies encountered adherent bowel inside the hernia sac. One reported linea alba injury with subsequent anterior layer dehiscence. There was one case of unrecognised intraoperative retromuscular bleeding and one case of insufflation injury with subcutaneous emphysema. There is a paucity of literature on the incidence of intraoperative complications in robotic-assisted eTEP ventral hernia repairs. Available studies suggest complication rates are low. More robust studies using prospective data from hernia registries are required before further conclusions can be drawn.

The Role of Artificial Intelligence in Colorectal Cancer Screening: Lesion Detection and Lesion Characterization.

Colorectal cancer remains a leading cause of cancer-related morbidity and mortality worldwide, despite the widespread uptake of population surveillance strategies. This is in part due to the persistent development of 'interval colorectal cancers', where patients develop colorectal cancer despite appropriate surveillance intervals, implying pre-malignant polyps were not resected at a prior colonoscopy. Multiple techniques have been developed to improve the sensitivity and accuracy of lesion detection and characterisation in an effort to improve the efficacy of colorectal cancer screening, thereby reducing the incidence of interval colorectal cancers. This article presents a comprehensive review of the transformative role of artificial intelligence (AI), which has recently emerged as one such solution for improving the quality of screening and surveillance colonoscopy. Firstly, AI-driven algorithms demonstrate remarkable potential in addressing the challenge of overlooked polyps, particularly polyp subtypes infamous for escaping human detection because of their inconspicuous appearance. Secondly, AI empowers gastroenterologists without exhaustive training in advanced mucosal imaging to characterise polyps with accuracy similar to that of expert interventionalists, reducing the dependence on pathologic evaluation and guiding appropriate resection techniques or referrals for more complex resections. AI in colonoscopy holds the potential to advance the detection and characterisation of polyps, addressing current limitations and improving patient outcomes. The integration of AI technologies into routine colonoscopy represents a promising step towards more effective colorectal cancer screening and prevention.

Significance of intra-operative cholangiogram and its application in suspected duodenal injuries - Case report.

INTRODUCTION AND IMPORTANCE: Intraoperative cholangiogram has always been a critical procedure that allows identification of biliary anatomy, thereby reducing the risks of bile duct injuries. CASE PRESENTATION: We present a unique case where the intraoperative cholangiogram highlighted a suspected duodenal injury. CLINICAL DISCUSSION: This case discusses the intraoperative steps taken to ensure there was no injury, highlight the importance of cholangiogram interpretation as a skill for all surgeons. CONCLUSION: Intraoperative cholangiogram is a crucial procedure to highlight both biliary and non-biliary anatomy and can be used to identify duodenal injuries as was assessed in our case.

Well-hidden methanogenesis in deep, organic-rich sediments of Guaymas Basin.

Deep marine sediments (>1mbsf) harbor ~26% of microbial biomass and are the largest reservoir of methane on Earth. Yet, the deep subsurface biosphere and controls on its contribution to methane production remain underexplored. Here, we use a multidisciplinary approach to examine methanogenesis in sediments (down to 295 mbsf) from sites with varying degrees of thermal alteration (none, past, current) at Guaymas Basin (Gulf of California) for the first time. Traditional (13C/12C and D/H) and multiply substituted (13CH3D and 12CH2D2) methane isotope measurements reveal significant proportions of microbial methane at all sites, with the largest signal at the site with past alteration. With depth, relative microbial methane decreases at differing rates between sites. Gibbs energy calculations confirm methanogenesis is exergonic in Guaymas sediments, with methylotrophic pathways consistently yielding more energy than the canonical hydrogenotrophic and acetoclastic pathways. Yet, metagenomic sequencing and cultivation attempts indicate that methanogens are present in low abundance. We find only one methyl-coenzyme M (mcrA) sequence within the entire sequencing dataset. Also, we identify a wide diversity of methyltransferases (mtaB, mttB), but only a few sequences phylogenetically cluster with methylotrophic methanogens. Our results suggest that the microbial methane in the Guaymas subsurface was produced over geologic time by relatively small methanogen populations, which have been variably influenced by thermal sediment alteration. Higher resolution metagenomic sampling may clarify the modern methanogen community. This study highlights the importance of using a multidisciplinary approach to capture microbial influences in dynamic, deep subsurface settings like Guaymas Basin.