Tyndall Centre

DNA polymerases are complex molecular machines capable of replicating genetic material using a template-driven process. While the copying function of these enzymes is well established, their ability to perform untemplated DNA synthesis is less well characterized. Here, we explore the ability of DNA polymerases to synthesize DNA fragments in the absence of a template. We use long-read nanopore sequencing, real-time fluorescence assays, and atomic force microscopy to observe the synthesis and physical structure of pools of DNA products derived from a diverse set of natural and engineered DNA polymerases across varying temperatures and buffer compositions. We detail the features of the DNA fragments generated, enrichment of select sequence motifs, and demonstrate that the sequence composition of the synthesized DNA can be altered by modifying environmental conditions. This work provides extensive data to better discern the process of untemplated DNA polymerase activity and may support its potential repurposing as a technology for the guided synthesis of DNA sequences on the kilobase-scale and beyond.

Abstract The increasing demand for three-dimensional dynamic environmental perception is driving interest in solid-state frequency-modulated continuous-wave (FMCW) LiDAR technologies. However, integrated FMCW LiDAR based on either optical phased arrays (OPAs) or focal-plane arrays (FPAs) face intrinsic trade-offs that have not yet been addressed simultaneously. Here, we present a biaxial FMCW LiDAR architecture that monolithically integrates an OPA transmitter with a coherent FPA receiver, comprising over 4500 functional components and implemented on separate optical paths in a circulator-free configuration. The architecture combines the complementary strengths of OPAs and FPAs. The OPA easily supports high optical power handling and provides agile line-by-line steering enabled by an engineered line-shaped beam. The FPA can form a large receiving aperture assisted by an imaging lens and enables parallel coherent signal readout at a single wavelength. The system achieves single-wavelength three-dimensional imaging with a ranging distance of 20 m using 3.7 mW of emitted optical power. A depth resolution of 5 cm and a velocity resolution of 1 mm/s are obtained. Parallel point-cloud at 10 frames per second (fps) is demonstrated, while acquisition rates of up to 62 fps are supported by the architecture. These results position the biaxial OPA-FPA architecture as a compact and practical system-level approach for integrated FMCW LiDAR.

Concurrent extreme fire weather creates favorable conditions for widespread large fires, which can complicate the coordination of fire suppression resources and degrade regional air quality. Here, we examine the patterns and trends of intra- and interregional synchronous fire weather (SFW) and explore their links to climate variability and air quality impacts. We find climatologically elevated intraregional SFW in boreal regions, as well as interregional synchronicity among northern temperate and boreal regions. Significant increases in SFW occurred during 1979 to 2024, with more than a twofold increase observed in most regions. We estimate that over half of the observed increase is attributable to anthropogenic climate change. Internal modes of climate variability strongly influence SFW in several regions, including Equatorial Asia, which experiences 43 additional intraregional SFW days during El Niño years. Furthermore, SFW is strongly correlated with regional fire-sourced PM2.5 in multiple regions globally. These findings highlight the growing challenges posed by SFW for firefighting coordination and human health.

Pyocyanin (PYO) is a quorum-sensing signaling molecule that is secreted exclusively by Pseudomonas aeruginosa (P. aeruginosa). The monitoring of PYO concentrations can therefore be used to readily detect the presence of P. aeruginosa. Dissolved oxygen interference has hampered the use of materials for sensors, such as gold, for PYO detection, unless degassing of samples is incorporated, limiting the point-of-care applicability. To this end, carbon-based electrodes are typically employed but are limited in terms of reproducibility and miniaturization. In this work, we report oxygen interference-free electrochemical detection of PYO using an unmodified gold interdigitated array. Through the use of redox cycling, dissolved oxygen interference was minimized, and highly sensitive detection was achieved in both buffered conditions (73.4 nM) and real-world samples (100 nM). Additionally, multiple strains of P. aeruginosa were investigated, and the sensor was found to be highly accurate for all three strains (PA17, PA40, PA41) and demonstrated good agreement with the typical UV-Vis detection method employed. This approach demonstrates the potential for future point-of-care testing for PYO, and thereby P. aeruginosa, using these sensors without the need for sample modification.

Vertical land motion (VLM) is an underrecognized hazard in susceptible coastal cities, especially those experiencing rapid urbanization. Human-induced VLM often causes elevation loss (subsidence) at rates that exceed, sometimes by an order of magnitude or more, those of climate-driven sea-level rise. Local land subsidence (LLS) also damages infrastructure, disrupts drainage, and alters flood dynamics, yet its broader impacts remain poorly quantified and systematically assessed. This review synthesizes the scientific, technical, and policy dimensions of VLM, with particular focus on LLS, highlighting how natural processes and human activities interact to amplify coastal hazards. We examine the geophysical drivers of VLM, advances in monitoring and modeling, and their integration into hazard assessment frameworks. We consider socioeconomic and infrastructural vulnerabilities of city residents, especially where limited observational capacity and governance gaps intensify risk. VLM acts as both a physical amplifier and a socio-institutional blind spot within coastal adaptation planning, requiring real-time data integration, scenario testing, and inclusive policy development. Finally, we identify key research frontiers—including subsidence mitigation strategies, dynamic VLM projections, and equitable, high-resolution risk assessment—to support more resilient, adaptive, and just coastal futures. ▪ Tectonics, sediment compaction, groundwater extraction, and urban loading combine to produce complex, nonlinear patterns of vertical land motion that shape local hazard dynamics. ▪ Local land subsidence, often exceeding the rate of global sea-level rise, is the dominant and least understood driver of coastal flooding and infrastructure risk in many urban regions worldwide. ▪ Subsidence disproportionately affects marginalized communities, exacerbating social inequities, driving displacement, and eroding cultural heritage, underscoring the need for inclusive, justice-centered adaptation frameworks. ▪ Closing critical data and policy gaps through coordinated vertical land motion observation, open-access standards, and equitable governance is essential to safeguard coastal populations and sustain long-term urban resilience.

Atomic force microscopy (AFM) is a widely used techniquefor high-resolutionimaging and force sensing, yet its performance is fundamentally constrainedby the cantilever size, spring constants, and mechanical frequencies.To overcome these limitations, we present a compact and highly efficientsingle-mode ring resonator-based optomechanical transducer on an silicon-on-insulator(SOI) platform. Unlike conventional designs that rely on whisperinggallery modes (WGMs) resonators, our approach ensures mode stability,facilitates straightforward signal interpretation, and enhances measurementreliability by eliminating mode-splitting effects and complex opticalresponses. Coupled with a picogram-scale cantilever, our system achievesexceptional displacement resolution of 6.7 × 10–16 m/Hz1/2 and force detection down to 5.0 × 10–14 N, providing a high-performance alternative to existingoptomechanical AFM transducers. The tunable mechanical resonance frequency(1.3 to 22.5 MHz) and adjustable stiffness (0.46 to 3.54 N/m) enableprecise force sensing across a broad range of applications, from softmatter characterization to high-speed imaging. Importantly, our resultsexhibit strong agreement with theoretical predictions, ensuring accurateand direct displacement measurements. Our results establish this single-modeoptomechanical transducer as a robust, high-sensitivity platform fornext-generation AFM and nanoscale sensing applications, offering acompact, scalable, and highly precise alternative to traditional free-spaceoptical detection methods. The combination of high displacement resolution,mode stability, and tunable performance establishes this optomechanicaltransducer as a promising advancement in integrated nanoscale sensingand AFM applications.

Luminol-based Electrochemiluminescence (ECL) generates weak signals in neutral media and typically requires H2O2 as a coreactant. However, H2O2 instability and the need for on-site addition hinder real-time diagnostic applications. Compact integrated sensing platforms are ideal for point-of-care (POC) testing due to portability, low sample requirements, and multiplexing. However, as sensor dimensions decrease, the low light emission issue in ECL becomes severe. We introduce a novel fully integrated miniaturized silicon device consisting of three sensors comprised of unique entwined micro-spiral electrodes in a generator-collector configuration. This enables highly sensitive, coreactant-free multiplexed sensing at physiological pH by accelerating in-situ reactive oxygen species production and boosting ECL intensity. Systematic optimization of electrode geometry (gaps and widths) yields an 11-fold improvement in ECL signal compared to a single-electrode setup, as well as excellent reproducibility and stability. In addition to Trolox and H2O2 detection, the platform demonstrates multiplex immunosensing through selective functionalization of the collector electrodes with chitosan nanocomposites, followed by Protein A/G-assisted immobilization of anti-IgG antibodies with peptide-based antifouling. The immunosensors exhibit high analytical performance (linear range: 0.001-100 pg mL-1, detection limit: 0.8 fg mL-1) with excellent reproducibility and reliability in 25% fetal bovine serum, highlighting the platforms potential for sensitive, coreactant-free multi-analyte POC diagnostics.

ABSTRACTThe temporal distribution of rainfall is a key driver of flood response. Yet, flood estimation methods are frequently based on symmetrical design profiles. Recent research using sub‐hourly rainfall data from Great Britain indicates that a significant proportion of observed rainfall events are non‐symmetrical. This paper investigates how different rainfall profiles affect river flow hydrographs for a set of small, flash‐flooding catchments. Results show that rainfall profiles affect observed hydrograph peak flow and timing. Most importantly, back‐loaded rainfall profiles lead to higher peak flows than symmetrical or front‐loaded profiles. These observations are compared to current design practice, using the Revitalised Flood Hydrograph (ReFH2.3) model to simulate flows from different rainfall profiles. Simulated events reproduce the observed response of peak magnitude but differ for peak time. A comparison of modelled flows with catchment descriptors indicates that steep, low permeability, wet catchments are most sensitive to rainfall profile shape. These are also the most vulnerable catchments to flash flooding. We recommend that different rainfall profile shapes should be considered for flood risk assessments in rapid response catchments, particularly since global warming is increasing the number of intense, short‐duration downpours.