Author Correction: Magnetic flux trapping in hydrogen-rich high-temperature superconductors
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Hydrogen is of interest for decarbonizing hard-to-abate sectors because it does not produce carbon dioxide when combusted. However, hydrogen has indirect warming effects. Here we conducted a life cycle assessment of electrolysis and steam methane reforming to assess their emissions while considering hydrogen’s indirect warming effects. We find that the primary factors influencing life cycle climate impacts are the production method and related feedstock emissions rather than the hydrogen leakage and indirect warming potential. A comparison between fossil fuel-based and hydrogen-based steel production and heavy-duty transportation showed a reduction in emissions of 800 to more than 1400 kg carbon dioxide equivalent per tonne of steel and 0.1 to 0.17 kg carbon dioxide equivalent per tonne-km of cargo. While any hydrogen production pathway reduces greenhouse gas emissions for steel, this is not the case for heavy-duty transportation. Therefore, we recommend a sector-specific approach in prioritizing application areas for hydrogen.
Autophagy repression by antigen and cytokines shapes mitochondrial, migration and effector machinery in CD8 T cells
Autophagy shapes CD8 T cell fate; yet the timing, triggers and targets of this process are poorly defined. Herein, we show that naive CD8 T cells have high autophagic flux, and we identify an autophagy checkpoint whereby antigen receptor engagement and inflammatory cytokines acutely repress autophagy by regulating amino acid transporter expression and intracellular amino acid delivery. Activated T cells with high levels of amino acid transporters have low autophagic flux in amino-acid-replete conditions but rapidly reinduce autophagy when amino acids are restricted. A census of proteins degraded and fueled by autophagy shows how autophagy shapes CD8 T cell proteomes. In cytotoxic T cells, dominant autophagy substrates include cytolytic effector molecules, and amino acid and glucose transporters. In naive T cells, mitophagy dominates and selective mitochondrial pruning supports the expression of molecules that coordinate T cell migration and survival. Autophagy thus differentially prunes naive and effector T cell proteomes and is dynamically repressed by antigen receptors and inflammatory cytokines to shape T cell differentiation.
Optical sorting: past, present and future
Optical sorting combines optical tweezers with diverse techniques, including optical spectrum, artificial intelligence (AI) and immunoassay, to endow unprecedented capabilities in particle sorting. In comparison to other methods such as microfluidics, acoustics and electrophoresis, optical sorting offers appreciable advantages in nanoscale precision, high resolution, non-invasiveness, and is becoming increasingly indispensable in fields of biophysics, chemistry, and materials science. This review aims to offer a comprehensive overview of the history, development, and perspectives of various optical sorting techniques, categorised as passive and active sorting methods. To begin, we elucidate the fundamental physics and attributes of both conventional and exotic optical forces. We then explore sorting capabilities of active optical sorting, which fuses optical tweezers with a diversity of techniques, including Raman spectroscopy and machine learning. Afterwards, we reveal the essential roles played by deterministic light fields, configured with lens systems or metasurfaces, in the passive sorting of particles based on their varying sizes and shapes, sorting resolutions and speeds. We conclude with our vision of the most promising and futuristic directions, including AI-facilitated ultrafast and bio-morphology-selective sorting. It can be envisioned that optical sorting will inevitably become a revolutionary tool in scientific research and practical biomedical applications.
A robust organic hydrogen sensor for distributed monitoring applications
Hydrogen is an abundant and clean energy source that could help to decarbonize difficult-to-electrify economic sectors. However, its safe deployment relies on the availability of cost-effective hydrogen detection technologies. We describe a hydrogen sensor that uses an organic semiconductor as the active layer. It can operate over a wide temperature and humidity range. Ambient oxygen p-dopes the organic semiconductor, which improves hole transport, and the presence of hydrogen reverses this doping process, leading to a drop in current and enabling reliable and rapid hydrogen detection. The sensor exhibits a high responsivity (more than 10,000), fast response time (less than 1 s), low limit of detection (around 192 ppb) and low power consumption (less than 2 μW). It can operate continuously for more than 646 days in ambient air at room temperature. We show that the sensor outperforms a commercial hydrogen detector in realistic sensing scenarios, illustrating its suitability for application in distributed sensor networks for early warning of hydrogen leaks and preventing explosions or fires.
Revealing the molecular interplay of coverage, wettability, and capacitive response at the Pt(111)-water solution interface under bias
While electrified interfaces are crucial for electrocatalysis and corrosion, their molecular morphology remains largely unknown. Through highly realistic ab initio molecular dynamics simulations of the Pt(111)-water solution interface in reducing conditions, we reveal a deep interconnection among electrode coverage, wettability, capacitive response, and catalytic activity. We identify computationally the experimentally hypothesised states for adsorbed hydrogen on Pt, HUPD and HOPD, revealing their role in governing interfacial water reorientation and hydrogen evolution. The transition between these two H states with increasing potential, induces a shift from a hydrophobic to a hydrophilic interface and correlates with a change in the primary electrode screening mechanism. This results in a slope change in differential capacitance, marking the onset of the experimentally observed peak around the potential of zero charge. Our work produces crucial insights for advancing electrocatalytic energy conversion, developing deep understanding of electrified interfaces.
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