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Climate warming will influence photosynthesis via thermal effects and by altering soil moisture 1 – 11 . Both effects may be important for the vast areas of global forests that fluctuate between periods when cool temperatures limit photosynthesis and periods when soil moisture may be limiting to carbon gain 4 – 6 , 9 – 11 . Here we show that the effects of climate warming flip from positive to negative as southern boreal forests transition from rainy to modestly dry periods during the growing season. In a three-year open-air warming experiment with juveniles of 11 temperate and boreal tree species, an increase of 3.4 °C in temperature increased light-saturated net photosynthesis and leaf diffusive conductance on average on the one-third of days with the wettest soils. In all 11 species, leaf diffusive conductance and, as a result, light-saturated net photosynthesis decreased during dry spells, and did so more sharply in warmed plants than in plants at ambient temperatures. Consequently, across the 11 species, warming reduced light-saturated net photosynthesis on the two-thirds of days with driest soils. Thus, low soil moisture may reduce, or even reverse, the potential benefits of climate warming on photosynthesis in mesic, seasonally cold environments, both during drought and in regularly occurring, modestly dry periods during the growing season. Low soil moisture may reduce, or even reverse, the potential benefits of climate warming on photosynthesis in mesic, seasonally cold environments, both during drought and in regularly occurring, modestly dry periods during the growing season.

We examine a nonreciprocally coupled dynamical model of a mixture of two diffusing species. We demonstrate that nonreciprocity, which is encoded in the model via antagonistic cross-diffusivities, provides a generic mechanism for the emergence of traveling patterns in purely diffusive systems with conservative dynamics. In the absence of nonreciprocity, the binary fluid mixture undergoes a phase transition from a homogeneous mixed state to a demixed state with spatially separated regions rich in one of the two components. Above a critical value of the parameter tuning nonreciprocity, the static demixed pattern acquires a finite velocity, resulting in a state that breaks both spatial and time-reversal symmetry, as well as the reflection parity of the static pattern. We elucidate the generic nature of the transition to traveling patterns using a minimal model that can be studied analytically. Our work has direct relevance to nonequilibrium assembly in mixtures of chemically interacting colloids that are known to exhibit nonreciprocal effective interactions, as well as to mixtures of active and passive agents where traveling states of the type predicted here have been observed in simulations. It also provides insight on transitions to traveling and oscillatory states seen in a broad range of nonreciprocal systems with nonconservative dynamics, from reaction–diffusion and prey–predators models to multispecies mixtures of microorganisms with antagonistic interactions.

Rotary molecular machines, activated by ultraviolet light, are able to perturb and drill into cell membranes in a controllable manner, and more efficiently than those exhibiting flip-flopping or random motion. Molecular machine 'drills' through cell membranes Victor García-López et al . report that ultraviolet-light-activated rotary molecular machines are able to perturb and drill into cell membranes in vitro . Molecules without the drilling action, which either flip-flopped in a washing-machine-like motion or demonstrated random rotation, were inefficient at traversing the cell membrane compared to those with unidirectional motion. Membrane perturbation was rapidly followed by membrane blebbing, and necrosis. Changing the structure of the motors sterically slowed the transport across the membrane, while the addition of peptides to the molecular motors allowed targeting of the molecules to specific cells. This research offers new opportunities for molecular motors in bioengineering applications. Beyond the more common chemical delivery strategies, several physical techniques are used to open the lipid bilayers of cellular membranes 1 . These include using electric 2 and magnetic 3 fields, temperature 4 , ultrasound 5 or light 6 to introduce compounds into cells, to release molecular species from cells or to selectively induce programmed cell death (apoptosis) or uncontrolled cell death (necrosis). More recently, molecular motors and switches that can change their conformation in a controlled manner in response to external stimuli have been used to produce mechanical actions on tissue for biomedical applications 7 , 8 , 9 . Here we show that molecular machines can drill through cellular bilayers using their molecular-scale actuation, specifically nanomechanical action. Upon physical adsorption of the molecular motors onto lipid bilayers and subsequent activation of the motors using ultraviolet light, holes are drilled in the cell membranes. We designed molecular motors and complementary experimental protocols that use nanomechanical action to induce the diffusion of chemical species out of synthetic vesicles, to enhance the diffusion of traceable molecular machines into and within live cells, to induce necrosis and to introduce chemical species into live cells. We also show that, by using molecular machines that bear short peptide addends, nanomechanical action can selectively target specific cell-surface recognition sites. Beyond the in vitro applications demonstrated here, we expect that molecular machines could also be used in vivo , especially as their design progresses to allow two-photon, near-infrared and radio-frequency activation 10 .

The dynamics of a general reaction–diffusion–advection two species model with nonlocal delay effect and Dirichlet boundary condition is investigated in this paper. The existence and stability of the positive spatially nonhomogeneous steady state solution are studied. Then by regarding the time delay τ as the bifurcation parameter, we show that Hopf bifurcation occurs near the steady state solution at the critical values τ n ( n = 0 , 1 , 2 , … ) . Moreover, the Hopf bifurcation is forward and the bifurcated periodic solutions are stable on the center manifold. The general results are applied to a Lotka–Volterra competition–diffusion–advection model with nonlocal delay.

Perovskite solar cells (PSCs) comprise a solid perovskite absorber sandwiched between several layers of different charge-selective materials, ensuring unidirectional current flow and high voltage output of the devices 1 , 2 . A ‘buffer material’ between the electron-selective layer and the metal electrode in p-type/intrinsic/n-type (p-i-n) PSCs (also known as inverted PSCs) enables electrons to flow from the electron-selective layer to the electrode 3 – 5 . Furthermore, it acts as a barrier inhibiting the inter-diffusion of harmful species into or degradation products out of the perovskite absorber 6 – 8 . Thus far, evaporable organic molecules 9 , 10 and atomic-layer-deposited metal oxides 11 , 12 have been successful, but each has specific imperfections. Here we report a chemically stable and multifunctional buffer material, ytterbium oxide (YbO x ), for p-i-n PSCs by scalable thermal evaporation deposition. We used this YbO x buffer in the p-i-n PSCs with a narrow-bandgap perovskite absorber, yielding a certified power conversion efficiency of more than 25%. We also demonstrate the broad applicability of YbO x in enabling highly efficient PSCs from various types of perovskite absorber layer, delivering state-of-the-art efficiencies of 20.1% for the wide-bandgap perovskite absorber and 22.1% for the mid-bandgap perovskite absorber, respectively. Moreover, when subjected to ISOS-L-3 accelerated ageing, encapsulated devices with YbO x exhibit markedly enhanced device stability. Ytterbium oxide buffer layer for use in perovskite solar cells yields a certified power conversion efficiency of more than 25%, which enhances stability across a wide variety of perovskite compositions.

Hydrogen peroxide (H 2 O 2 ) functions as a second messenger to signal metabolic distress through highly compartmentalized production in mitochondria. The dynamics of reactive oxygen species (ROS) generation and diffusion between mitochondrial compartments and into the cytosol govern oxidative stress responses and pathology, though these processes remain poorly understood. Here, we couple the H 2 O 2 biosensor, HyPer7, with optogenetic stimulation of the ROS-generating protein KillerRed targeted into multiple mitochondrial microdomains. Single mitochondrial photogeneration of H 2 O 2 demonstrates the spatiotemporal dynamics of ROS diffusion and transient hyperfusion of mitochondria due to ROS. This transient hyperfusion phenotype required mitochondrial fusion but not fission machinery. Measurement of microdomain-specific H 2 O 2 diffusion kinetics reveals directionally selective diffusion through mitochondrial microdomains. All-optical generation and detection of physiologically-relevant concentrations of H 2 O 2 between mitochondrial compartments provide a map of mitochondrial H 2 O 2 diffusion dynamics in situ as a framework to understand the role of ROS in health and disease. How ROS diffuse and are cleared between mitochondrial compartments governs oxidative stress and cell signaling. Here, authors map the kinetics of ROS dynamics using optogenetics and discover acute ROS transiently elongates mitochondria.

Many biological processes are executed and regulated through the molecular interactions of proteins and nucleic acids. Proximity labeling (PL) is a technology for tagging the endogenous interaction partners of specific protein ‘baits’, via genetic fusion to promiscuous enzymes that catalyze the generation of diffusible reactive species in living cells. Tagged molecules that interact with baits can then be enriched and identified by mass spectrometry or nucleic acid sequencing. Here we review the development of PL technologies and highlight studies that have applied PL to the discovery and analysis of molecular interactions. In particular, we focus on the use of PL for mapping protein–protein, protein–RNA and protein–DNA interactions in living cells and organisms.This Review describes proximity labeling methods that make use of peroxidases (APEX) or biotin ligases (TurboID, BioID), and their applications to studying protein–protein and protein–nucleic acid interactions in living systems.

The modeling of reactive transport through porous media is a challenging numerical problem. Methods of solution have leveraged the stoichiometry of chemical reactions to address the transport of multiple aqueous species by expressing them in terms of an equivalent, linearly independent variable (component). This approach effectively decouples advection‐dispersion transport from the source terms associated with equilibrium reactions. A common assumption found in the literature is that all species disperse with the same transport coefficients. Recent experimental studies have discussed that this is not necessarily the case, particularly for transverse mixing, which is limited by the species‐specific molecular diffusion. This article presents a formulation of multicomponent reactive transport that takes into account the differences in dispersion coefficients. These differences lead to a nonlinear transport equation for the components, from where an expression for evaluating reaction rates is derived. It is demonstrated that this expression simplifies to the well‐known equations assuming the same dispersion for all species. Numerical simulations of a binary chemical system under diffusion‐ and advection‐dominated transport conditions are used to evaluate the influence that differential transport coefficients have upon the output of chemical reactions. Results indicate that differences in transport coefficients are particularly relevant when the chemical signature of the input solutions is not strongly dominated by one of the species in the component. Unexpectedly, this opens the possibility to mineral dissolution coexisting with precipitation during the mixing of two waters in equilibrium. This phenomenon can be explained by nonlinear mixing processes proportional to the differences in transport coefficients. Key Points New formulation of multicomponent reactive transport with species‐specific dispersion properties and nonlinear transport for the components A general expression for evaluating reaction rates is derived considering the transport properties of all species Differences in coefficients can lead to dissolution coexisting with precipitation for a equilibrium binary reaction in dilute systems

Lithium–sulfur battery possesses high energy density but suffers from severe capacity fading due to the dissolution of lithium polysulfides. Novel design and mechanisms to encapsulate lithium polysulfides are greatly desired by high-performance lithium–sulfur batteries towards practical applications. Herein, we report a strategy of utilizing anthraquinone, a natural abundant organic molecule, to suppress dissolution and diffusion of polysulfides species through redox reactions during cycling. The keto groups of anthraquinone play a critical role in forming strong Lewis acid-based chemical bonding. This mechanism leads to a long cycling stability of sulfur-based electrodes. With a high sulfur content of ~73%, a low capacity decay of 0.019% per cycle for 300 cycles and retention of 81.7% over 500 cycles at 0.5 C rate can be achieved. This finding and understanding paves an alternative avenue for the future design of sulfur–based cathodes toward the practical application of lithium–sulfur batteries. Novel cathode design holds the key to enabling high performance lithium-sulfur batteries. Here the authors utilize anthraquinone to chemically stabilize polysulfides, revealing that the keto groups of anthraquinone play a critical role in forming strong Lewis acid-based chemical bonding.

The meticulous design of advanced electrocatalysts and their integration into gas diffusion electrode (GDE) architectures is emerging as a prominent research paradigm in the H 2 O 2 electrosynthesis community. However, it remains perplexing that electrocatalysts and assembled GDE frequently exhibit substantial discrepancies in H 2 O 2 selectivity during bulk electrolysis. Here, we elucidate the pivotal role of mass transfer behavior of key species (including reactants and products) beyond the intrinsic properties of the electrocatalyst in dictating electrode-scale H 2 O 2 selectivity. This tendency becomes more pronounced in high reaction rate (current density) regimes where transport limitations are intensified. By utilizing diffusion-related parameters (DRP) of GDEs (i.e., wettability and catalyst layer thickness) as probe factors, we employ both short- and long-term electrolysis in conjunction with in-situ electrochemical reflection-absorption imaging and theoretical calculations to thoroughly investigate the impact of DRP and DRP-controlled local microenvironments on O 2 and H 2 O 2 mass transfer. The mechanistic origins of diffusion-dependent conversion selectivity at the electrode scale are unveiled accordingly. The fundamental insights gained from this study underscore the necessity of architectural innovations for mainstream hydrophobic GDEs that can synchronously optimize mass transfer of reactants and products, paving the way for next-generation GDEs in gas-consuming electroreduction scenarios. Electrocatalysts and assembled gas diffusion electrodes frequently exhibit discrepancies in selectivity during H 2 O 2 electrosynthesis. Here, the authors report the pivotal role of key species transport beyond the intrinsic properties of electrocatalysts in dictating electrode-scale H 2 O 2 selectivity.