Superionic iron hydride shapes ultralow-velocity zones at Earth's core-mantle boundary.

Seismological studies have exposed numerous ultralow velocity zones (ULVZs) exhibiting extraordinary physical attributes at Earth's core-mantle boundary, yet their compositions and origins remain controversial. Water-iron reaction can generate unique phases under lowermost-mantle conditions and likely plays a crucial role in forming ULVZs. Through first-principles molecular dynamic simulations with machine learning techniques, we determine that iron hydride, the product of water-iron reaction, is stable as a superionic phase at the core-mantle boundary. This superionic iron hydride has much slower velocities and a higher density than the ambient mantle under lowermost-mantle conditions. Accumulation of iron hydride, created through either a chemical reaction between subducted water and iron or solidification of core material entrained in the lower mantle by convection, can explain the seismic observations of ULVZs particularly those associated with subduction. This work suggests that water may have a substantial role in creating seismic heterogeneities at the core-mantle boundary.

Acknowledging more biodiversity without more species.

Delimiting and naming biodiversity is a vital step toward wildlife conservation and research. However, species delimitation must be consistent across biota so that the limited resources available for nature protection can be spent effectively and objectively. To date, newly discovered lineages typically are either left undescribed and thus remain unprotected or are being erroneously proposed as new species despite mixed evidence for completed speciation, in turn contributing to the emerging problem of taxonomic inflation. Inspired by recent conceptual and methodological progress, we propose a standardized workflow for species delimitation that combines phylogenetic and hybrid zone analyses of genomic datasets ("genomic taxonomy"), in which phylogeographic lineages that do not freely admix are ranked as species, while those that have remained fully genetically compatible are ranked as subspecies. In both cases, we encourage their formal taxonomic naming, diagnosis, and description to promote social awareness toward biodiversity. The use of loci throughout the genome overcomes the unreliability of widely used barcoding genes when phylogeographic patterns are complex, while the evaluation of divergence and reproductive isolation unifies the long-opposed concepts of lineage species and biological species. We suggest that a shift in conservation assessments from a single level (species) toward a two-level hierarchy (species and subspecies) will lead to a more balanced perception of biodiversity in which both intraspecific and interspecific diversity are valued and more adequately protected.

Carbonates and intermediate-depth seismicity: Stable and unstable shear in altered subducting plates and overlying mantle.

A model for intermediate-depth earthquakes of subduction zones is evaluated based on shear localization, shear heating, and runaway creep within thin carbonate layers in an altered downgoing oceanic plate and the overlying mantle wedge. Thermal shear instabilities in carbonate lenses add to potential mechanisms for intermediate-depth seismicity, which are based on serpentine dehydration and embrittlement of altered slabs or viscous shear instabilities in narrow fine-grained olivine shear zones. Peridotites in subducting plates and the overlying mantle wedge may be altered by reactions with CO2-bearing fluids sourced from seawater or the deep mantle, to form carbonate minerals, in addition to hydrous silicates. Effective viscosities of magnesian carbonates are higher than those for antigorite serpentine and they are markedly lower than those for H2O-saturated olivine. However, magnesian carbonates may extend to greater mantle depths than hydrous silicates at temperatures and pressures of subduction zones. Strain rates within altered downgoing mantle peridotites may be localized within carbonated layers following slab dehydration. A simple model of shear heating and temperature-sensitive creep of carbonate horizons, based on experimentally determined creep laws, predicts conditions of stable and unstable shear with strain rates up to 10/s, comparable to seismic velocities of frictional fault surfaces. Applied to intermediate-depth earthquakes of the Tonga subduction zone and the double Wadati-Benioff zone of NE Japan, this mechanism provides an alternative to the generation of earthquakes by dehydration embrittlement, beyond the stability of antigorite serpentine in subduction zones.

Supercritical fluid in deep subduction zones as revealed by multiphase fluid inclusions in an ultrahigh-pressure metamorphic vein.

Due to their low viscosity, high mobility, and high element contents, supercritical fluids are important agents in the cycling of elements. However, the chemical composition of supercritical fluids in natural rocks is poorly understood. Here, we investigate well-preserved primary multiphase fluid inclusions (MFIs) from an ultrahigh-pressure (UHP) metamorphic vein of the Bixiling eclogite in Dabieshan, China, thus providing direct evidence for the components of supercritical fluid occurring in a natural system. Via the 3D modeling of MFIs by Raman scanning, we quantitatively determined the major composition of the fluid trapped in the MFIs. Combined with the peak-metamorphic pressure-temperature conditions and the cooccurrence of coesite, rutile, and garnet, we suggest that the trapped fluids in the MFIs represent supercritical fluids in a deep subduction zone. The strong mobility of the supercritical fluids with respect to carbon and sulfur suggests that such fluids have profound effects on global carbon and sulfur cycling.

AID and Reactive Oxygen Species Can Induce DNA Breaks within Human Chromosomal Translocation Fragile Zones.

DNA double-strand breaks (DSBs) occurring within fragile zones of less than 200 base pairs account for the formation of the most common human chromosomal translocations in lymphoid malignancies, yet the mechanism of how breaks occur remains unknown. Here, we have transferred human fragile zones into S. cerevisiae in the context of a genetic assay to understand the mechanism leading to DSBs at these sites. Our findings indicate that a combination of factors is required to sensitize these regions. Foremost, DNA strand separation by transcription or increased torsional stress can expose these DNA regions to damage from either the expression of human AID or increased oxidative stress. This damage causes DNA lesions that, if not repaired quickly, are prone to nuclease cleavage, resulting in DSBs. Our results provide mechanistic insight into why human neoplastic translocation fragile DNA sequences are more prone to enzymes or agents that cause longer-lived DNA lesions.

Spatiotemporal transcriptomic plasticity in barley roots: unravelling water deficit responses in distinct root zones.

BACKGROUND: Drought poses a major threat to agricultural production and thus food security. Understanding the processes shaping plant responses to water deficit is essential for global food safety. Though many studies examined the effect of water deficit on the whole-root level, the distinct functions of each root zone and their specific stress responses remain masked by this approach. RESULTS: In this study, we investigated the effect of water deficit on root development of the spring barley (Hordeum vulgare L.) cultivar Morex and examined transcriptomic responses at the level of longitudinal root zones. Water deficit significantly reduced root growth rates after two days of treatment. RNA-sequencing revealed root zone and temporal gene expression changes depending on the duration of water deficit treatment. The majority of water deficit-regulated genes were unique for their respective root zone-by-treatment combination, though they were associated with commonly enriched gene ontology terms. Among these, we found terms associated with transport, detoxification, or cell wall formation affected by water deficit. Integration of weighted gene co-expression analyses identified differential hub genes, that highlighted the importance of modulating energy and protein metabolism and stress response. CONCLUSION: Our findings provide new insights into the highly dynamic and spatiotemporal response cascade triggered by water deficit and the underlying genetic regulations on the level of root zones in the barley cultivar Morex, providing potential targets to enhance plant resilience against environmental constraints. This study further emphasizes the importance of considering spatial and temporal resolution when examining stress responses.

Hybridization has localized effect on genetic variation in closely related pine species.

BACKGROUND: Hybridization is a known phenomenon in nature but its genetic impact on populations of parental species remains less understood. We investigated the evolutionary consequences of the interspecific gene flow in several contact zones of closely related pine species. Using a set of genetic markers from both nuclear and organellar genomes, we analyzed four hybrid zones (384 individuals) and a large panel of reference allopatric populations of parental taxa (2104 individuals from 96 stands). RESULTS: We observed reduced genetic diversity in maternally transmitted mitochondrial genomes of pure pine species and hybrids from contact zones compared to reference allopatric populations. The distribution of mtDNA haplotypes followed geographic rather than species boundaries. Additionally, no new haplotypes emerged in the contact zones, instead these zones contained the most common local variants. However, species diverged significantly at nuclear genomes and populations in contact zones exhibited similar or higher genetic diversity compared to the reference stands. There were no signs of admixture in any allopatric population, while clear admixture was evident in the contact zones, indicating that hybridization has a geographically localized effect on the genetic variation of the analyzed pine species. CONCLUSIONS: Our results suggest that hybrid zones act as sinks rather than melting pots of genetic diversity. Hybridization influences sympatric populations but is confined to contact zones. The spectrum of parental species ancestry in hybrids reflects the old evolutionary history of the sympatric populations. These findings also imply that introgression may play a crucial role in the adaptation of hybrids to specific environments.

GPT-4-based AI agents-the new expert system for detection of antimicrobial resistance mechanisms?

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommends two steps for detecting beta-lactamases in Gram-negative bacteria. Screening for potential extended-spectrum beta-lactamase (ESBL), plasmid-mediated AmpC beta-lactamase, or carbapenemase production is confirmed. We aimed to validate generative pre-trained transformer (GPT)-4 and GPT-agent for pre-classification of disk diffusion to indicate potential beta-lactamases. We assigned 225 Gram-negative isolates based on phenotypic resistances against beta-lactam antibiotics and additional tests to one or more resistance mechanisms as follows: "none," "ESBL," "AmpC," or "carbapenemase." Next, we customized a GPT-agent with EUCAST guidelines and breakpoint table (v13.1). We compared routine diagnostics (reference) to those of (i) EUCAST-GPT-expert, (ii) microbiologists, and (iii) non-customized GPT-4. We determined sensitivities and specificities to flag suspect resistances. Three microbiologists showed concordance in 814/862 (94.4%) phenotypic categories and were used in median eight words (interquartile range [IQR] 4-11) for reasoning. Median sensitivity/specificity for ESBL, AmpC, and carbapenemase were 98%/99.1%, 96.8%/97.1%, and 95.5%/98.5%, respectively. Three prompts of EUCAST-GPT-expert showed concordance in 706/862 (81.9%) categories but were used in median 158 words (IQR 140-174) for reasoning. Sensitivity/specificity for ESBL, AmpC, and carbapenemase prediction were 95.4%/69.23%, 96.9%/86.3%, and 100%/98.8%, respectively. Non-customized GPT-4 could interpret 169/862 (19.6%) categories, and 137/169 (81.1%) agreed with routine diagnostics. Non-customized GPT-4 was used in median 85 words (IQR 72-105) for reasoning. Microbiologists showed higher concordance and shorter argumentations compared to GPT-agents. Humans showed higher specificities compared to GPT-agents. GPT-agent's unspecific flagging of ESBL and AmpC potentially results in additional testing, diagnostic delays, and higher costs. GPT-4 is not approved by regulatory bodies, but validation of large language models is needed. IMPORTANCE: The study titled "GPT-4-based AI agents-the new expert system for detection of antimicrobial resistance mechanisms?" is critically important as it explores the integration of advanced artificial intelligence (AI) technologies, like generative pre-trained transformer (GPT)-4, into the field of laboratory medicine, specifically in the diagnostics of antimicrobial resistance (AMR). With the growing challenge of AMR, there is a pressing need for innovative solutions that can enhance diagnostic accuracy and efficiency. This research assesses the capability of AI to support the existing two-step confirmatory process recommended by the European Committee on Antimicrobial Susceptibility Testing for detecting beta-lactamases in Gram-negative bacteria. By potentially speeding up and improving the precision of initial screenings, AI could reduce the time to appropriate treatment interventions. Furthermore, this study is vital for validating the reliability and safety of AI tools in clinical settings, ensuring they meet stringent regulatory standards before they can be broadly implemented. This could herald a significant shift in how laboratory diagnostics are performed, ultimately leading to better patient outcomes.

Diversity of bacterial communities in wetlands of Calakmul Biosphere Reserve: a comparative analysis between conserved and semi-urbanized zones in pre-Mayan Train era.

BACKGROUND: The Calakmul Biosphere Reserve (CBR) is known for its rich animal and plant biodiversity, yet its microbial communities remain largely unknown. The reserve does not possess permanent bodies of water; nevertheless, seasonal depressions associated with fractures create wetlands, known locally as aguadas. Given the recent construction of the Maya train that crosses the CRB, it is essential to assess the biodiversity of its microorganisms and recognize their potential as a valuable source of goods. This evaluation is pivotal in mitigating potential mismanagement of the forest ecosystem. To enhance comprehension of microbial communities, we characterized the microbiota in three different wetlands. Ag-UD1 and Ag-UD2 wetlands are located in a zone without human disturbances, while the third, Ag-SU3, is in a semi-urbanized zone. Sampling was carried out over three years (2017, 2018, and 2019), enabling the monitoring of spatiotemporal variations in bacterial community diversity. The characterization of microbiome composition was conducted using 16S rRNA metabarcoding. Concurrently, the genomic potential of select samples was examined through shotgun metagenomics. RESULTS: Statistical analysis of alpha and beta diversity indices showed significant differences among the bacterial communities found in undisturbed sites Ag-UD1 and Ag-UD2 compared to Ag-SU3. However, no significant differences were observed among sites belonging to the undisturbed area. Furthermore, a comparative analysis at the zone level reveals substantial divergence among the communities, indicating that the geographic location of the samples significantly influences these patterns. The bacterial communities in the CBR wetlands predominantly consist of genera from phyla Actinobacteria, Acidobacteria, and Proteobacteria. CONCLUSION: This characterization has identified the composition of microbial communities and provided the initial overview of the metabolic capacities of the microbiomes inhabiting the aguadas across diverse conservation zones. The three sites exhibit distinct microbial compositions, suggesting that variables such as chemical composition, natural and anthropogenic disturbances, vegetation, and fauna may play a pivotal role in determining the microbial structure of the aguadas. This study establishes a foundational baseline for evaluating the impact of climatic factors and human interventions on critical environments such as wetlands.

Phylogeography and paleoclimatic range dynamics explain variable outcomes to contact across a species' range.

Replicability of divergence after contact is a poorly characterized process, particularly in the contexts of phylogeography and postglacial range dynamics within species. Using contact zones located at the leading-, mid- and rear-edges of a species' range, we examined variation in outcomes to contact between divergent lineages of Campanula americana. We investigated whether contact zones vary in quantity and directionality of gene flow, how phylogeographic structure differs between contact zones, and how historic range dynamics may affect outcomes to contact. We found that all contact zones formed at similar times via primary contact yet detected significant admixture in only the rear-edge (RE) contact zone. In the northern leading-edge contact zone and the mid-range Virginia contact zone, gene flow was minimal and asymmetric. In the southern RE contact zone, gene flow was strong and symmetric. Asymmetric admixture in the leading-edge and Virginia contact zones matches the directionality of a known cosmopolitan cytonuclear incompatibility between lineages of C. americana. Our results emphasize the dependence of speciation processes on phylogeographic structure, evolutionary history and range dynamics.

Predictors of low-voltage zones in patients with persistent atrial fibrillation eligible for catheter ablation: An observational study.

INTRODUCTION: The presence of low-voltage zones (LVZs) in the left atrium (LA) is associated with the recurrence of atrial fibrillation (AF) following pulmonary vein isolation (PVI). However, there is variability and conflict in the data regarding predictors of LVZs as reported in previous studies. The objective of this study was to identify predictors for the presence of LVZs in a cohort of patients with persistent AF. METHODS: The study prospectively enrolled 439 patients with persistent AF who were scheduled for ablation. Voltage map of the LA was collected using a multipolar catheter. An LVZ was defined as an area of ≥3 cm2 exhibiting a peak-to-peak bipolar voltage of <0.5 mV. RESULTS: The mean age of the cohort was 65.3 ± 8.6 years and 26.4% were female. Additionally, 25.7% had significant LVZs, most frequently located in the anterior wall of the LA. Multivariable analysis identified the following independent predictors for LVZ: advanced age (OR [odds ratio] = 1.08, 95% CI [confidence interval] = 1.03-1.13, p = .002); female sex (OR = 4.83, 95% CI = 2.66-8.76, p < .001); coronary artery disease (CAD) (OR = 3.20, 95% CI = 1.32-7.77, p = .01) and enlarged LA diameter (OR = 1.10, 95% CI = 1.04-1.17, p = .001). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for the final model was 0.829. CONCLUSION: Approximately 25% of the patients with persistent AF had LVZs. Advanced age, female sex, CAD, and a larger LA were independent predictors for LVZs with the model demonstrating a very good AUC for the ROC curve. These findings hold the potential to be used to tailor the ablation procedure for the individual patient.

Declining coupling between vegetation and drought over the past three decades.

Droughts have been implicated as the main driver behind recent vegetation die-off and are projected to drive greater mortality under future climate change. Understanding the coupling relationship between vegetation and drought has been of great global interest. Currently, the coupling relationship between vegetation and drought is mainly evaluated by correlation coefficients or regression slopes. However, the optimal drought timescale of vegetation response to drought, as a key indicator reflecting vegetation sensitivity to drought, has largely been ignored. Here, we apply the optimal drought timescale identification method to examine the change in coupling between vegetation and drought over the past three decades (1982-2015) with long-term satellite-derived Normalized Difference Vegetation Index and Standardized Precipitation-Evapotranspiration Index data. We find substantial increasing response of vegetation to drought timescales globally, and the correlation coefficient between vegetation and drought under optimal drought timescale overall declines between 1982 and 2015. This decrease in vegetation-drought coupling is mainly observed in regions with water deficit, although its initial correlation is relatively high. However, vegetation in water-surplus regions, with low coupling in earlier stages, is prone to show an increasing trend. The observed changes may be driven by the increasing trend of atmospheric CO2 . Our findings highlight more pressing drought risk in water-surplus regions than in water-deficit regions, which advances our understanding of the long-term vegetation-drought relationship and provides essential insights for mapping future vegetation sensitivity to drought under changing climate conditions.

The effects of modern housing on malaria transmission in different endemic zones: a systematic review and meta-analysis.

BACKGROUND: Modern housing has been shown to reduce the risk of malaria infections compared to traditional houses; however, it is unclear if the effects differ in different malaria transmission settings. This study evaluated the effects of modern housing on malaria among different endemic areas. METHODS: Electronic databases, clinical trial registries and grey literature were searched for randomized controlled trials, cohort studies, case-control studies, and cross-sectional surveys on housing done between 1987 and 2022. Forest plots were done, and the quality of evidence was assessed using the Grading of Recommendations, Assessments, Development and Evaluation Framework. RESULTS: Twenty-one studies were included; thirteen were cross-sectional, four were case-control and four were cohort studies. Cohort studies showed an adjusted risk ratio of 0.68 (95% CI 0.48-0.96), and cross-sectional studies indicated an adjusted odds ratio (aOR) of 0.79 (95%CI 0.75-0.83). By endemic transmission regions, the adjusted odds ratio in the high endemic settings was 0.80 (95%CI 0.76-085); in the moderate transmission regions, aOR = 0.76 (95%CI 0.67-0.85) and in the low transmission settings, aOR = 0.67 (95%CI 0.48-0.85). CONCLUSIONS: The evidence from observational studies suggests that there are no differences in the protective effects of modern houses compared to traditional houses on malaria by endemicity level. This implies that good quality modern housing protects against malaria regardless of the malaria transmission settings.

Prefiltered component-based greedy (PreCoG) scan method.

The spatial distribution of disease cases can provide important insights into disease spread and its potential risk factors. Identifying disease clusters correctly can help us discover new risk factors and inform interventions to control and prevent the spread of disease as quickly as possible. In this study, we propose a novel scan method, the Prefiltered Component-based Greedy (PreCoG) scan method, which efficiently and accurately detects irregularly shaped clusters using a prefiltered component-based algorithm. The PreCoG scan method's flexibility allows it to perform well in detecting both regularly and irregularly-shaped clusters. Additionally, it is fast to apply while providing high power, sensitivity, and positive predictive value for the detected clusters compared to other scan methods. To confirm the effectiveness of the PreCoG method, we compare its performance to many other scan methods. Additionally, we have implemented this method in the smerc R package to make it publicly available to other researchers. Our proposed PreCoG scan method presents a unique and innovative process for detecting disease clusters and can improve the accuracy of disease surveillance systems.

Children's Health in London and Luton (CHILL) cohort: a 12-month natural experimental study of the effects of the Ultra Low Emission Zone on children's travel to school.

BACKGROUND: The Ultra-Low Emission Zone (ULEZ), introduced in Central London in April 2019, aims to enhance air quality and improve public health. The Children's Health in London and Luton (CHILL) study evaluates the impact of the ULEZ on children's health. This analysis focuses on the one-year impacts on the shift towards active travel to school. METHODS: CHILL is a prospective parallel cohort study of ethnically diverse children, aged 6-9 years attending 84 primary schools within or with catchment areas encompassing London's ULEZ (intervention) and Luton (non-intervention area). Baseline (2018/19) and one-year follow-up (2019/20) data were collected at school visits from 1992 (58%) children who reported their mode of travel to school 'today' (day of assessment). Multilevel logistic regressions were performed to analyse associations between the introduction of the ULEZ and the likelihood of switching from inactive to active travel modes, and vice-versa. Interactions between intervention group status and pre-specified effect modifiers were also explored. RESULTS: Among children who took inactive modes at baseline, 42% of children in London and 20% of children in Luton switched to active modes. For children taking active modes at baseline, 5% of children in London and 21% of children in Luton switched to inactive modes. Relative to the children in Luton, children in London were more likely to have switched from inactive to active modes (OR 3.64, 95% CI 1.21-10.92). Children in the intervention group were also less likely to switch from active to inactive modes (OR 0.11, 0.05-0.24). Moderator analyses showed that children living further from school were more likely to switch from inactive to active modes (OR 6.06,1.87-19.68) compared to those living closer (OR 1.43, 0.27-7.54). CONCLUSIONS: Implementation of clean air zones can increase uptake of active travel to school and was particularly associated with more sustainable and active travel in children living further from school.

A data-driven approach to multiple-stressor impact assessment for a marine protected area.

The coastal environment is not managed in a way that considers the impact of cumulative threats, despite being subject to threats from all realms (marine, land, and atmosphere). Relationships between threats and species are often nonlinear; thus, current (linear) approaches to estimating the impact of threats may be misleading. We developed a data-driven approach to assessing cumulative impacts on ecosystems and applied it to explore nonlinear relationships between threats and a temperate reef fish community. We used data on water quality, commercial fishing, climate change, and indicators of recreational fishing and urbanization to build a cumulative threat map of the northern region in New South Wales, Australia. We used statistical models of fish abundance to quantify associations among threats and biophysical covariates and predicted where cumulative impacts are likely to have the greatest impact on fish. We also assessed the performance of no-take zones (NTZs), to protect fish from cumulative threats across 2 marine protected area networks (marine parks). Fishing had a greater impact on fish than water quality threats (i.e., percent increase above the mean for invertivores was 337% when fishing was removed and was 11% above the mean when water quality was removed inside NTZs), and fishing outside NTZs affected fish abundances inside NTZs. Quantifying the spatial influence of multiple threats enables managers to understand the multitude of management actions required to address threats.

Una estrategia basada en datos para la evaluación de impacto de múltiples estresores en un área marina protegida Resumen Los ambientes costeros no se manejan de manera que se considere el impacto de las amenazas acumulativas, a pesar de que se enfrentan a amenazas de todos los entornos (marinas, terrestres y atmosféricas). Las relaciones entre las amenazas y las especies casi siempre son no lineales; por lo tanto, las estrategias actuales (lineales) para estimar el impacto de las amenazas pueden ser engañosas. Desarrollamos una estrategia basada en datos para evaluar el impacto acumulativo sobre los ecosistemas y la aplicamos para explorar las relaciones no lineales entre las amenazas y la comunidad de peces de arrecifes templados. Usamos datos de la calidad del agua, pesca comercial, cambio climático e indicadores de pesca recreativa y urbanización para construir un mapa acumulativo de amenazas de la región norte de Nueva Gales del Sur, Australia. Usamos modelos estadísticos de la abundancia de peces para cuantificar las asociaciones entre las amenazas y las covarianzas biofísicas y pronosticamos en dónde es probable que los impactos acumulativos sean mayores sobre los peces. También evaluamos el desempeño de las zonas de veda para así proteger a los peces de las amenazas acumulativas en dos redes de áreas marinas protegidas (parques marinos). La pesca tuvo un mayor impacto que la calidad del agua sobre los peces (es decir, el incremento del porcentaje por encima de la media de depredadores de invertebrados fue de 337% cuando se eliminó la pesca y fue de 11% por encima de la media cuando se eliminó la calidad del agua dentro de las zonas de veda) y la pesca fuera de las zonas de veda afectó la abundancia de los peces dentro de ellas. La cuantificación de la influencia espacial de las múltiples amenazas permite que los gestores entiendan la multitud de acciones de manejo que se requieren para abordar las amenazas.

Non-invasive detection of slow conduction with cardiac magnetic resonance imaging for ventricular tachycardia ablation.

AIMS: Non-invasive myocardial scar characterization with cardiac magnetic resonance (CMR) has been shown to accurately identify conduction channels and can be an important aid for ventricular tachycardia (VT) ablation. A new mapping method based on targeting deceleration zones (DZs) has become one of the most commonly used strategies for VT ablation procedures. The aim of the study was to analyse the capability of CMR to identify DZs and to find predictors of arrhythmogenicity in CMR channels. METHODS AND RESULTS: Forty-four consecutive patients with structural heart disease and VT undergoing ablation after CMR at a single centre (October 2018 to July 2021) were included (mean age, 64.8 ± 11.6 years; 95.5% male; 70.5% with ischaemic heart disease; a mean ejection fraction of 32.3 ± 7.8%). The characteristics of CMR channels were analysed, and correlations with DZs detected during isochronal late activation mapping in both baseline maps and remaps were determined. Overall, 109 automatically detected CMR channels were analysed (2.48 ± 1.15 per patient; length, 57.91 ± 63.07 mm; conducting channel mass, 2.06 ± 2.67 g; protectedness, 21.44 ± 25.39 mm). Overall, 76.1% of CMR channels were associated with a DZ. A univariate analysis showed that channels associated with DZs were longer [67.81 ± 68.45 vs. 26.31 ± 21.25 mm, odds ratio (OR) 1.03, P = 0.010], with a higher border zone (BZ) mass (2.41 ± 2.91 vs. 0.87 ± 0.86 g, OR 2.46, P = 0.011) and greater protectedness (24.97 ± 27.72 vs. 10.19 ± 9.52 mm, OR 1.08, P = 0.021). CONCLUSION: Non-invasive detection of targets for VT ablation is possible with CMR. Deceleration zones found during electroanatomical mapping accurately correlate with CMR channels, especially those with increased length, BZ mass, and protectedness.

Human Exposure to Ambient Atmospheric Microplastics in a Megacity: Spatiotemporal Variation and Associated Microorganism-Related Health Risk.

Microplastics are found in various human tissues and are considered harmful, raising concerns about human exposure to microplastics in the environment. Existing research has analyzed indoor and occupational scenarios, but long-term monitoring of ambient atmospheric microplastics (AMPs), especially in highly polluted urban regions, needs to be further investigated. This study estimated human environmental exposure to AMPs by considering inhalation, dust ingestion, and dermal exposure in three urban functional zones within a megacity. The annual exposure quantity was 7.37 × 104 items for children and 1.06 × 105 items for adults, comparable with the human microplastic consumption from food and water. Significant spatiotemporal differences were observed in the characteristics of AMPs that humans were exposed to, with wind speed and rainfall frequency mainly driving these changes. The annual human AMP exposure quantity in urban green land spaces, which were recognized as relatively low polluted zones, was comparable with that in public service zones and residential zones. Notably, significant positive correlations between the AMP characteristics and the pathogenicity of the airborne bacterial community were discovered. AMP size and immune-mediated disease risks brought by atmospheric microbes showed the most significant relationship, where Sphingomonas might act as the potential key mediator.

Seasonal and Spatial Fluctuations of Reactive Oxygen Species in Riparian Soils and Their Contributions on Organic Carbon Mineralization.

Reactive oxygen species (ROS) are ubiquitous in the natural environment and play a pivotal role in biogeochemical processes. However, the spatiotemporal distribution and production mechanisms of ROS in riparian soil remain unknown. Herein, we performed uninterrupted monitoring to investigate the variation of ROS at different soil sites of the Weihe River riparian zone throughout the year. Fluorescence imaging and quantitative analysis clearly showed the production and spatiotemporal variation of ROS in riparian soils. The concentration of superoxide (O2•-) was 300% higher in summer and autumn compared to that in other seasons, while the highest concentrations of 539.7 and 20.12 µmol kg-1 were observed in winter for hydrogen peroxide (H2O2) and hydroxyl radicals (•OH), respectively. Spatially, ROS production in riparian soils gradually decreased along with the stream. The results of the structural equation and random forest model indicated that meteorological conditions and soil physicochemical properties were primary drivers mediating the seasonal and spatial variations in ROS production, respectively. The generated •OH significantly induced the abiotic mineralization of organic carbon, contributing to 17.5-26.4% of CO2 efflux. The obtained information highlighted riparian zones as pervasive yet previously underestimated hotspots for ROS production, which may have non-negligible implications for carbon turnover and other elemental cycles in riparian soils.

Mercury Stable Isotopes Reveal the Vertical Distribution and Trophic Ecology of Deep-Pelagic Organisms over the North-East Atlantic Ocean Continental Slope.

Deep-pelagic species are central to marine ecosystems and increasingly vulnerable to global change and human exploitation. To date, our understanding of these communities remains limited mainly due to the difficulty of observations, calling for complementary innovative tools to better characterize their ecology. We used mercury (Δ199Hg, δ202Hg, Δ201Hg, and Δ200Hg), carbon (δ13C), and nitrogen (δ15N) stable isotope compositions to segregate deep-pelagic species caught on the continental slope of the Bay of Biscay (NE Atlantic) according to their foraging depth and trophic ecology. Decreasing fish Δ199Hg values with corresponding depth estimates from the surface to down to 1,800 m confirmed that mercury isotopes are able to segregate deep species over a large vertical gradient according to their foraging depth. Results from isotopic compositions also identified different mercury sources, likely reflecting different trophic assemblages over the continental slope, in particular, the demersal influence for some species, compared to purely oceanic species. Overall, our results demonstrate how mercury stable isotopes can inform the vertical foraging habitat of little-known species and communities feeding in the deep.