The occurrence of faults in the Bunter Sandstone Formation of the UK Sector of the Southern North Sea and the potential impact on storage capacity

The Triassic Bunter Sandstone Formation of the Southern North Sea is believed to have significant potential to store CO2 for climate change mitigation [1]. It has fair to good reservoir properties and a seal is provided by the mudstones of the Triassic Haisborough Group. It has been folded into domes and periclines (henceforth Bunter domes) by the post depositional late Triassic to Tertiary movement of the underlying evaporites of the Zechstein Group. These domes have been identified as targets for CO2 storage as they are very large and at least some of them have the ability to retain buoyant fluids, demonstrated by the presence of gas fields in some domes [2], [3], [4], [5] (though the majority of the formation is saline water-bearing). However, faults have been identified within the Haisborough Group cap rock directly above a number of the Bunter domes. The faults are thought to have formed as result of extensional stresses exerted during dome formation. They may have an impact on storage site security, as they could act as migration pathways for CO2 out of the storage site and therefore limit the number of Bunter domes that could be utilised for storage of CO2. This study considers the occurrence of faults in the cap rock above the Bunter domes and the potential impact on static capacity estimates

Evaluation of barriers to national CO2 geological storage assessments

A survey to evaluate the main perceived barriers to national CO2 storage assessments was carried out in 2015, targeting countries where some Carbon dioxide Capture and Storage (CCS) activity was known or where CCS could potentially be implemented in the future. All the questionnaire respondents indicated that some level of national assessment had been achieved. In most cases, these assessments had been sufficient to allow policy makers to make informed decisions about priorities for follow-up actions. Where national storage assessments had been carried out, the major barriers had been mainly overcome through strong political and regulatory support for CCS and policies enabling access to relevant data

Single-photon electroluminescence for on-chip quantum networks

An electrically driven single-photon source has been monolithically integrated with nano-photonic circuitry. Electroluminescent emission from a single InAs/GaAs quantum dot (QD) is channelled through a suspended nanobeam waveguide. The emission line has a linewidth of below 6 μeV, demonstrating the ability to have a high coherence, electrically driven, waveguide coupled QD source. The single-photon nature of the emission is verified by g(2) (τ) correlation measurements. Moreover, in a cross-correlation experiment, with emission collected from the two ends of the waveguide, the emission and propagation of single photons from the same QD is confirmed. This work provides the basis for the development of electrically driven on-chip single-photon sources, which can be readily coupled to waveguide filters, directional couplers, phase shifters, and other elements of quantum photonic networks

Fine-scale structure of the mid-mantle characterised by global stacks of PP precursors

Subduction zones are likely a major source of compositional heterogeneities in the mantle, which may preserve a record of the subduction history and mantle convection processes. The fine-scale structure associated with mantle heterogeneities can be studied using the scattered seismic wavefield that arrives as coda to or as energy preceding many body wave arrivals. In this study we analyse precursors to PP by creating stacks recorded at globally distributed stations. We create stacks aligned on the PP arrival in 5° distance bins (with range 70-120°) from 600 earthquakes recorded at 193 stations stacking a total of 7320 seismic records. As the energy trailing the direct P arrival, the P coda, interferes with the PP precursors, we suppress the P coda by subtracting a best fitting exponential curve to this energy. The resultant stacks show that PP precursors related to scattering from heterogeneities in the mantle are present for all distances. Lateral variations are explored by producing two regional stacks across the Atlantic and Pacific hemispheres, but we find only negligible differences in the precursory signature between these two regions. The similarity of these two regions suggests that well mixed subducted material can survive at upper and mid-mantle depth. To describe the scattered wavefield in the mantle, we compare the global stacks to synthetic seismograms generated using a Monte Carlo phonon scattering technique. We propose a best-fitting layered heterogeneity model, BRT2017, characterised by a three layer mantle with a background heterogeneity strength (ϵ = 0.8%) and a depth-interval of increased heterogeneity strength (ϵ = 1%) between 1000 km and 1800 km. The scalelength of heterogeneity is found to be 8 km throughout the mantle. Since mantle heterogeneity of 8 km scale may be linked to subducted oceanic crust, the detection of increased heterogeneity at mid-mantle depths could be associated with stalled slabs due to increases in viscosity, supporting recent observations of mantle viscosity increases due to the iron spin transition at depths of ~1000 k

Nonreciprocal transmission and reflection of a chirally coupled quantum dot

We report strongly non-reciprocal behaviour for quantum dot exciton spins coupled to nano-photonic waveguides under resonant laser excitation. A clear dependence of the transmission spectrum on the propagation direction is found for a chirally-coupled quantum dot, with spin up and spin down exciton spins coupling to the left and right propagation directions respectively. The reflection signal shows an opposite trend to the transmission, which a numerical model indicates is due to direction-selective saturation of the quantum dot. The chiral spin-photon interface we demonstrate breaks reciprocity of the system and opens the way to spin-based quantum optical components such as optical diodes and circulators in a chip-based solid-state environment

The evolution of lung cancer and impact of subclonal selection in TRACERx

Lung cancer is the leading cause of cancer-associated mortality worldwide. Here we analysed 1,644 tumour regions sampled at surgery or during follow-up from the first 421 patients with non-small cell lung cancer prospectively enrolled into the TRACERx study. This project aims to decipher lung cancer evolution and address the primary study endpoint: determining the relationship between intratumour heterogeneity and clinical outcome. In lung adenocarcinoma, mutations in 22 out of 40 common cancer genes were under significant subclonal selection, including classical tumour initiators such as TP53 and KRAS. We defined evolutionary dependencies between drivers, mutational processes and whole genome doubling (WGD) events. Despite patients having a history of smoking, 8% of lung adenocarcinomas lacked evidence of tobacco-induced mutagenesis. These tumours also had similar detection rates for EGFR mutations and for RET, ROS1, ALK and MET oncogenic isoforms compared with tumours in never-smokers, which suggests that they have a similar aetiology and pathogenesis. Large subclonal expansions were associated with positive subclonal selection. Patients with tumours harbouring recent subclonal expansions, on the terminus of a phylogenetic branch, had significantly shorter disease-free survival. Subclonal WGD was detected in 19% of tumours, and 10% of tumours harboured multiple subclonal WGDs in parallel. Subclonal, but not truncal, WGD was associated with shorter disease-free survival. Copy number heterogeneity was associated with extrathoracic relapse within 1 year after surgery. These data demonstrate the importance of clonal expansion, WGD and copy number instability in determining the timing and patterns of relapse in non-small cell lung cancer and provide a comprehensive clinical cancer evolutionary data resource

The artificial intelligence-based model ANORAK improves histopathological grading of lung adenocarcinoma

The introduction of the International Association for the Study of Lung Cancer grading system has furthered interest in histopathological grading for risk stratification in lung adenocarcinoma. Complex morphology and high intratumoral heterogeneity present challenges to pathologists, prompting the development of artificial intelligence (AI) methods. Here we developed ANORAK (pyrAmid pooliNg crOss stReam Attention networK), encoding multiresolution inputs with an attention mechanism, to delineate growth patterns from hematoxylin and eosin-stained slides. In 1,372 lung adenocarcinomas across four independent cohorts, AI-based grading was prognostic of disease-free survival, and further assisted pathologists by consistently improving prognostication in stage I tumors. Tumors with discrepant patterns between AI and pathologists had notably higher intratumoral heterogeneity. Furthermore, ANORAK facilitates the morphological and spatial assessment of the acinar pattern, capturing acinus variations with pattern transition. Collectively, our AI method enabled the precision quantification and morphology investigation of growth patterns, reflecting intratumoral histological transitions in lung adenocarcinoma

Evolutionary characterization of lung adenocarcinoma morphology in TRACERx

Lung adenocarcinomas (LUADs) display a broad histological spectrum from low-grade lepidic tumors through to mid-grade acinar and papillary and high-grade solid, cribriform and micropapillary tumors. How morphology reflects tumor evolution and disease progression is poorly understood. Whole-exome sequencing data generated from 805 primary tumor regions and 121 paired metastatic samples across 248 LUADs from the TRACERx 421 cohort, together with RNA-sequencing data from 463 primary tumor regions, were integrated with detailed whole-tumor and regional histopathological analysis. Tumors with predominantly high-grade patterns showed increased chromosomal complexity, with higher burden of loss of heterozygosity and subclonal somatic copy number alterations. Individual regions in predominantly high-grade pattern tumors exhibited higher proliferation and lower clonal diversity, potentially reflecting large recent subclonal expansions. Co-occurrence of truncal loss of chromosomes 3p and 3q was enriched in predominantly low-/mid-grade tumors, while purely undifferentiated solid-pattern tumors had a higher frequency of truncal arm or focal 3q gains and SMARCA4 gene alterations compared with mixed-pattern tumors with a solid component, suggesting distinct evolutionary trajectories. Clonal evolution analysis revealed that tumors tend to evolve toward higher-grade patterns. The presence of micropapillary pattern and ‘tumor spread through air spaces’ were associated with intrathoracic recurrence, in contrast to the presence of solid/cribriform patterns, necrosis and preoperative circulating tumor DNA detection, which were associated with extra-thoracic recurrence. These data provide insights into the relationship between LUAD morphology, the underlying evolutionary genomic landscape, and clinical and anatomical relapse risk