Studying the composition of exoplanets is one of the most promising approaches to observationally constrain planet formation and evolution processes. However, this endeavour is complicated for small exoplanets by the fact that a wide range of compositions are compatible with their observed bulk properties. To overcome this issue, we identify triangular regions in the mass–radius space where part of this intrinsic degeneracy is lifted for close-in planets, since low-mass H/He envelopes would not be stable due to high-energy stellar irradiation. Planets in these Hot Water World triangles need to contain at least some heavier volatiles and are therefore interesting targets for atmospheric follow-up observations. We perform a demographic study to show that only few well-characterised planets in these regions are currently known and introduce our CHEOPS GTO programme aimed at identifying more of these potential hot water worlds. Here, we present CHEOPS observations for the first two targets of our programme, TOI-238 b and TOI-1685 b. Combined with TESS photometry and published RVs, we use the precise radii and masses of both planets to study their location relative to the corresponding Hot Water World triangles, perform an interior structure analysis, and study the possible lifetimes of H/He and waterdominated atmospheres under these conditions. We find that TOI-238 blies, at the 1σ level, inside the corresponding triangle. While a pure H/He atmosphere would have evaporated after 0.4–1.3 Myr, it is likely that a water-dominated atmosphere would have survived until the current age of the system, which makes TOI-238 ba promising candidate for a hot water world. Conversely, TOI-1685 b lies below the mass–radius model for a pure silicate planet, meaning that even though a water-dominated atmosphere would be compatible both with our internal structure and evaporation analysis, we cannot rule out the planet being a bare core.
View lessTuberculous mycobacterial infections pose a substantial global health burden because of their prevalence and multi-drug resistance. The current approach to tackling these infections primarily involves developing new antibiotics or combining existing ones, an approach that often proves ineffective in the specific targeting of mycobacteria.
We investigated the effect of sphingosine on tuberculous Mycobacteria in vitro and mycobacterial infections in vivo to test whether sphingosine could potentially be used as a novel drug against tuberculosis. Sphingosine inhibited mycobacterial growth and eradicated mycobacteria in vitro. Mechanistically, sphingosine increased bacterial membrane permeability and induced marked changes on the bacterial plasma membrane evidenced by electron microscopy studies. Administration of sphingosine in a mouse model of pulmonary infection with Bacillus Calmette–Guérin (BCG) greatly reduced the number of bacteria in the lung and prevented pulmonary inflammation. Furthermore, infection of ex vivo human lung tissue samples with BCG and treatment with sphingosine showed that sphingosine also kills BCG in human bronchi. Our findings suggest that sphingosine may be a potential therapeutic intervention against mycobacterial infections.
View lessUnderstanding how ecosystems respond to ubiquitous microplastic (MP) pollution is crucial for ensuring global food security. Here, we conduct a multiecosystem meta-analysis of 3,286 data points and reveal that MP exposure leads to a global reduction in photosynthesis of 7.05 to 12.12% in terrestrial plants, marine algae, and freshwater algae. These reductions align with those estimated by a constructed machine learning model using current MP pollution levels, showing that MP exposure reduces the chlorophyll content of photoautotrophs by 10.96 to 12.84%. Model estimates based on the identified MP-photosynthesis nexus indicate annual global losses of 4.11 to 13.52% (109.73 to 360.87 MT·y−1) for main crops and 0.31 to 7.24% (147.52 to 3415.11 MT C·y−1) for global aquatic net primary productivity induced by MPs. Under scenarios of efficient plastic mitigation, e.g., a ~13% global reduction in environmental MP levels, the MP-induced photosynthesis losses are estimated to decrease by ~30%, avoiding a global loss of 22.15 to 115.73 MT·y−1 in main crop production and 0.32 to 7.39 MT·y−1 in seafood production. These findings underscore the urgency of integrating plastic mitigation into global hunger and sustainability initiatives.
View lessOne of the key challenges in developing efficient organic light-emitting diodes (OLEDs) is overcoming the loss channel of triplet excitons. A common approach to mitigate these losses to enhance the external quantum efficiency of OLEDs is employing emitter molecules optimized for thermally activated delayed fluorescence (TADF) or triplet-triplet annihilation (TTA). However, achieving both in the solid state from the same organic chromophore poses a formidable challenge due to energetic and structural requirements needing to be met simultaneously. Here, we demonstrate TADF and TTA in donor-acceptor phthalimide derivatives by employing triphenylamine (TPA) or phenyl carbazole (PhCz) as a donor. Thin films of the TPA-substituted phthalimides doped in the poly(methyl methacrylate) matrix exhibit TADF emission from the singlet charge-transfer (CT) state. On the contrary, PhCz-substituted emitters display dominant TTA-induced delayed fluorescence in the neat film due to long-range molecular ordering that facilitates efficient triplet diffusion. The present study provides insight into how dual TADF-TTA delayed fluorescence can be realized in thin films of molecular semiconductors via rational molecular design.
View lessPredicting the solubility and lipophilicity of platinum(II, IV) complexes is essential for prioritizing potential anticancer candidates in drug discovery. This study introduces the first publicly available online model for predicting the solubility of platinum complexes, addressing the lack of literature and models in this regard. Using a time-split dataset, we developed a consensus model with a Root Mean Squared Error (RMSE) of 0.62 through 5-cross-validation on a training set of 284 historical compounds (solubility data reported prior to 2017). However, the RMSE increased to 0.86 when applied to a prospective test set of 108 compounds reported after 2017. Further analysis of the high prediction errors revealed that these inaccuracies are primarily attributed to the underrepresentation of novel chemical scaffolds, particularly Pt(IV) derivatives, in the training sets. For instance, a series of eight phenanthroline-containing compounds, not covered by the training set's chemical space, had an RMSE of 1.3. When the model was redeveloped using a combined dataset, the RMSE of this series significantly decreased to 0.34 under the same validation protocol. Additionally, we developed an interpretable linear model to identify structural features and functional groups that influence the solubility of platinum complexes. We further validated the correlation between solubility and lipophilicity, consistent with the Yalkowsky General Solubility Equation. Building on these insights, we developed a final multitask model that simultaneously predicts solubility and lipophilicity as two endpoints with RMSE = 0.62 and 0.44, respectively. The data and final developed model is available at https://ochem.eu/article/31.
View lessQuantum many-body scarring (QMBS) is an intriguing mechanism of weak ergodicity breaking that has recently spurred significant attention. Particularly prominent in Abelian lattice gauge theories (LGTs), an open question is whether QMBS nontrivially arises in non-Abelian LGTs. Here, we present evidence of robust QMBS in a non-Abelian SU(2) LGT with dynamical matter. Starting in product states that require little experimental overhead, we show that prominent QMBS arises for certain quenches, facilitated through meson and baryon-antibaryon excitations, highlighting its non-Abelian nature. The uncovered scarred dynamics manifests as long-lived coherent oscillations in experimentally accessible local observables as well as prominent revivals in the state fidelity. Our findings bring QMBS to the realm of non-Abelian LGTs, highlighting the intimate connection between scarring and gauge symmetry, and are amenable for observation in a recently proposed trapped-ion qudit quantum computer.
View lessFeedback control of open quantum systems is of fundamental importance for practical applications in various contexts, ranging from quantum computation to quantum error correction and quantum metrology. Its use in the context of thermodynamics further enables the study of the interplay between information and energy. However, deriving optimal feedback control strategies is highly challenging, as it involves the optimal control of open quantum systems, the stochastic nature of quantum measurement, and the inclusion of policies that maximize a long-term time- and trajectory-averaged goal. In this work, we employ a reinforcement learning approach to automate and capture the role of a quantum Maxwell's demon: the agent takes the literal role of discovering optimal feedback control strategies in qubit-based systems that maximize a trade-off between measurement-powered cooling and measurement efficiency. Considering weak or projective quantum measurements, we explore different regimes based on the ordering between the thermalization, the measurement, and the unitary feedback timescales, finding different and highly non-intuitive, yet interpretable, strategies. In the thermalization-dominated regime, we find strategies with elaborate finite-time thermalization protocols conditioned on measurement outcomes. In the measurement-dominated regime, we find that optimal strategies involve adaptively measuring different qubit observables reflecting the acquired information, and repeating multiple weak measurements until the quantum state is 'sufficiently pure', leading to random walks in state space. Finally, we study the case when all timescales are comparable, finding new feedback control strategies that considerably outperform more intuitive ones. We discuss a two-qubit example where we explore the role of entanglement and conclude discussing the scaling of our results to quantum many-body systems.
View lessThe increasing production of engineered nanomaterials (ENMs) raises significant concerns about human and environmental exposure, making it essential to understand the mechanisms of their interaction with biological systems to manage the associated risks. To address this, we propose categorizing ENM reactivity using in chemico methodologies. Surface analysis through methanol chemisorption and temperature-programmed surface reaction allows for the determination of reactive surface sites, providing accurate estimates of effective ENM doses in toxicity studies. Additionally, antioxidant consumption assays (dithiothreitol, cysteine, and glutathione) and reactive oxygen species (ROS) generation assays (RNO and DCFH2-DA) are employed to rank the oxidative potential of ENM surface sites in a cell-free environment. Our study confirms the classification of ZnO NM-110, ZnO NM-111, CuO, and carbon black as highly oxidant ENMs, while TiO2 NM-101 and NM-105 exhibit low oxidative potential due to their acidic surface sites. In contrast, CeO2 NM-211 and NM-212 demonstrate redox surface sites. SiO2 nanomaterials (NM-200 and NM-201) are shown to be inert, with low oxidation rates and minimal reactive surface density, despite their high surface area. Quantifying reactive surface sites offers a refined dose metric for assessing ENM toxicity, advancing safe-by-design nanomaterial development.
View lessSessilids (Oligohymenophorea, Peritrichia, Sessilida) reportedly colonize the gut of certain “higher termites” (family Termitidae), but only a single species, Termitophrya africana from Jugositermes tuberculatus (subfamily Apicotermitinae), has been described based on a drawing. Similar ciliates were observed in other Apicotermitinae but remained unspecified. Our SSU rRNA gene-based survey of peritrich ciliates in a broad range of Termitidae recovered distinct phylotypes from several Apicotermitinae (Astalotermes, Jugositermes, and Phoxotermes), albeit only from samples collected in Cameroon and not from all species of these genera. They form a monophyletic group in the family Epistylididae (Sessilida), with Orborhabdostyla bromelicola as the closest relative. Light, scanning, and transmission electron microscopy of the sessilid ciliates in J. tuberculatus revealed two morphotypes, which were assigned to their corresponding phylotypes by sequence analysis of capillary-picked single cells. One morphotype, which is highly contractile and broadens continuously towards the posterior end, matches the description of Termitophrya africana. The cells are attached by a posterior scopula with short cilia and are often covered with rod-shaped ectobionts. The other morphotype has a stockier, barrel-shaped body and a short, clearly demarcated anterior end and is always free of ectobionts. We designate it as Doliophrys denislynni gen. nov., sp. nov.
View lessUnequal political participation increasingly challenges democracies. The turnout gap is particularly large among younger voters, with severe implications for future developments of democratic representation, legitimacy, and quality. This article focuses on the role of political efficacy beliefs in explaining unequal turnout among newly enfranchised citizens. We argue that internal political efficacy beliefs are particularly important for turnout among the newly enfranchised from lower-class backgrounds, as they lack alternative mobilizing factors such as politically aware and active parents, political knowledge, and mobilizing networks. Furthermore, we argue that once these voters successfully turn out in their first election, they are as likely as those from higher-class backgrounds to turn out in their second election. We empirically test these arguments using original longitudinal data on newly enfranchised citizens from three German federal states (Bundesländer). Overall, our results support the argument: Political efficacy beliefs are a stronger predictor of first turnout among young adults from disadvantaged backgrounds compared to those from more advantaged backgrounds, and those who do turn out are as likely as those with higher-class backgrounds to turn out in their second election. This highlights the relevance of political efficacy beliefs in the (re)production of persisting political inequality.
View lessFuture quantum networks will have nodes equipped with multiple quantum memories, allowing for multiplexing and entanglement distillation strategies for long-distance entanglement distribution. In this work, we focus on quasi-local policies for multiplexed quantum repeater chains. In fully-local policies, nodes use the knowledge of only their own states, whereas more efficient global policies use knowledge of the entire network state. The classical communication costs of using this knowledge have not been explored in existing literature. We show that quasi-local policies not only obtain improved performance over local policies, but also reduce classical communication costs considerably. Our policies also outperform the widely studied nested purification and doubling policy in practical parameter regimes. We identify parameter regimes where distillation is useful and address the question: “Should we distill before swapping, or vice versa?” Finally, we propose an implementation scheme for a multiplexed repeater chain, experimentally demonstrate the key element, a high-dimensional biphoton frequency comb, and evaluate its anticipated performance using our multiplexing-based policies.
View lessCrSBr, a van der Waals material, stands out as an air-stable magnetic semiconductor with appealing intrinsic properties such as crystalline anisotropy, quasi-1D electronic characteristics, layer-dependent antiferromagnetism, and non-linear optical effects. We investigate the differences between the absorption and emission spectra, focusing on the origin of the emission peak near 1.7 eV observed in the photoluminescence spectrum of CrSBr. Our findings are corroborated by excitation energy-dependent Raman experiments. Additionally, we explore the anti-Stokes Raman spectra and observe an anomalously high anti-Stokes-to-Stokes intensity ratio of up to 0.8, which varies significantly with excitation laser power and crystallographic orientation relative to the polarization of the scattered light, highlighting the unique vibrational and electronic interactions in CrSBr. Lastly, we examine stimulated Raman scattering and calculate the Raman gain in CrSBr, which attains a value of 1 × 108 cm GW−1, nearly four orders of magnitude higher than that of previously studied three-dimensional systems.
View lessMotivated by the recent appearance of the trillium lattice in the search for materials hosting spin liquids, we study the ground state of the classical Heisenberg model on its line graph, the trilline lattice. We find that this network realizes the recently proposed notion of a fragile spin liquid in three dimensions. Additionally, we analyze the Ising case and argue for a possible ℤ2 quantum spin liquid phase in the corresponding quantum dimer model. Like the well-known 𝑈(1) spin liquids, the classical phase hosts moment fractionalization evidenced by the diluted lattice, but unlike those, it exhibits exponential decay in both spin correlations and interactions between fractionalized moments. This provides an instance of a purely short-range correlated classical Heisenberg spin liquid in three dimensions.
View lessDespite the various strategies that microorganisms have evolved to resist antibiotics, survival to drug treatments can be driven by subpopulations of susceptible bacteria in a transient state of dormancy. This phenotype, known as bacterial persistence, arises due to a natural and ubiquitous heterogeneity of growth states in bacterial populations. Nonetheless, the unifying mechanism of persistence remains unknown, with several pathways being able to trigger the phenotype. Here, we show that asymmetric damage partitioning, a form of cellular aging, produces the underlying phenotypic heterogeneity upon which persistence is triggered. Using single-cell microscopy and microfluidic devices, we demonstrate that deterministic asymmetry in exponential phase populations leads to a state of growth stability, which prevents the spontaneous formation of persisters. However, as populations approach stationary phase, aging bacteria—those inheriting more damage upon division—exhibit a sharper growth rate decline, increased probability of growth arrest, and higher persistence rates. These results indicate that persistence triggers are biased by bacterial asymmetry, thus acting upon the deterministic heterogeneity produced by cellular aging. This work suggests unifying mechanisms for persistence and offers new perspectives on the treatment of recalcitrant infections.
View lessIn spintronics, FM|HM stacks consisting of a ferromagnetic-metal (FM) and a heavy-metal (HM) layer are model systems for spin transport and spin-charge interconversion. To explore their potential as detectors for ultrabroadband terahertz electromagnetic pulses, we measure the transient optical birefringence the terahertz field induces. Notably, the signal component linear in the FM magnetization agrees excellently with the shape of the incident terahertz electric field at 1 to 13 terahertz and beyond. Analysis indicates that the birefringence arises from the terahertz-field–driven spin accumulation at the FM/HM interface through the spin Rashba-Edelstein effect (SREE). Because of spin-momentum locking, the SREE decays by electron momentum relaxation in <10 femtoseconds, substantially faster than a spin-Hall-effect–induced bulk spin accumulation. Our experiment demonstrates straightforward spintronic sampling of intense ultrabroadband terahertz fields with flat amplitude and phase response. Furthermore, it provides temporal signatures of the SREE and can be viewed as a versatile implementation of interface-specific terahertz time-domain spectroscopy.
View lessMaritime shipping is vital for commercial trade and well recognized as a main pathway for the spread of non-native species.1 For over a century, the Panama Canal in Central America has played a major role in global trade, connecting the Atlantic and Pacific oceans. Historically, the introduction of species through the Panama Canal has been relatively low, largely due to the existence of a soft barrier—the freshwater Lake Gatun—inside the canal.2,3,4 However, the 2016 expansion of the Panama Canal involved major structural changes to the canal’s lock system, which may have increased the likelihood that more marine fish species and greater numbers of them enter the lake and eventually cross the canal. To test this prediction, we used standardized quantitative comparisons of the fish communities of Lake Gatun, a system with a rich record of biological introductions,5,6 before (2013–2016) and after (2019–2023) the canal expansion. We observed a shift from a freshwater-dominated to a marine-dominated fish community in several areas inside the lake after 2016. The increase in marine organisms in this aquatic corridor may represent a potential invasion in progress, with a greater likelihood of some species eventually passing through the canal and colonizing the opposite ocean. The ecological and evolutionary consequences of these changes are difficult to predict. However, as most of these marine fishes are top predators with wide niche breadths, their colonization of Atlantic and Pacific oceans will likely alter ecological interactions and potentially lead to ecosystem-level changes.
View lessAnalyzing and developing new quantum error-correcting (QEC) schemes is one of the most prominent tasks in quantum computing research. In such efforts, introducing time dynamics explicitly in both analysis and design of error-correcting protocols constitutes an important cornerstone. In this work, we present a graphical formalism based on tensor networks to capture the logical action and error-correcting capabilities of any Clifford circuit with Pauli measurements. We showcase the functioning of the formalism on new Floquet codes derived from topological subsystem codes, which we call XYZ ruby codes. Based on the projective symmetries of the building blocks of the tensor network we develop a framework of Pauli flows. Pauli flows allow for a graphical understanding of all quantities entering an error-correction analysis of a circuit, including different types of QEC experiments, such as memory and stability experiments. We lay out how to derive a well-defined decoding problem from the tensor-network representation of a protocol and its Pauli flows alone, independent of any stabilizer code or fixed circuit. Importantly, this framework applies to all Clifford protocols and encompasses both measurement-based and circuit-based approaches to fault tolerance. We apply our method to our new family of dynamical codes, which are in the same topological phase as the 2 +1-dimensional color code, making them a promising candidate for low-overhead logical gates. In contrast to its static counterpart, the dynamical protocol applies a ℤ3 automorphism to the logical Pauli group every three time steps. We highlight some of its topological properties and comment on the anyon physics behind a planar layout. Lastly, we benchmark the performance of the XYZ ruby code on a torus by performing both memory and stability experiments and find competitive circuit-level noise thresholds of approximately equal to 0.18%, comparable with other Floquet codes and 2 +1-dimensional color codes.
View lessGraphene oxide (GO) has emerged as a promising biomaterial as it is easily and cheaply synthesized, strong, cytocompatible, osteoinductive, and has a well-characterized aqueous degradation pathway. It is also a great substrate for functionalization with biomolecules such as proteins, peptides, and small molecules that can enhance or add bioactivity. Covalent chemical linkages as opposed to typical noncovalent association methods are preferable so that the biomolecules do not quickly diffuse away or face replacement by other proteins, which is critical in long time scale applications like bone regeneration. However, covalent chemistry tends to carry a drawback of harsh reaction conditions that can damage the structure, conformation, and therefore function of a delicate biomolecule like a protein. Here, the Mitsunobu reaction is introduced as a novel method of covalently attaching proteins to graphene oxide. It features gentle reaction conditions and has the added benefit of utilizing the plentiful basal plane alcohol functionalities on graphene oxide, allowing for high yield protein functionalization. The amino acid Glycine (G), the protein bovine serum albumin (BSA), and the small molecule SVAK-12 are utilized to create the three Mitsunobu Graphene (MG) materials G-MG, BSA-MG, and SVAK-MG that demonstrate the wide applicability of this functionalization method.
View lessWith more than 2000 excavated archaeological iron artifacts, the Roman–Germanic conflict site Harzhorn is among the best-preserved battlefields from Classical Antiquity. The Harzhorn hogback, with its steep front face oriented to the north, is situated perpendicular to an important north–south passage west of the Harz Mountains in central Germany. The geological setting shows abrupt transitions at the surface between different Triassic and Quaternary deposits. To investigate possible relationships between the preservation status and detection probability of iron artifacts and geology, geomorphology, and properties of the substratum, 497 samples were investigated in terms of the pH value, electric conductivity, loss on ignition, and grain size. These parameters were systematically compared to the distribution, type, and preservation status of recovered iron objects. The pH value proved to be the most significant indicator for the preservation status. Within increasingly acidic environments, the iron objects showed severe corrosion damages, whereas the same type of objects showed a good preservation status when recovered from areas with more neutral pH values. Additionally, historical and modern human impacts on the landscape modified the distribution of finds. We mapped in detail areas with good, intermediate, and poor preservation conditions, which should be considered in the reconstruction of the battle.
View lessThe existing and rising anti-Semitism is a risk factor for the mental health of Jewish people worldwide. This study examines possible associations between anti-Semitism and mental health in offspring/children (OHS) and grandchildren (GHS) of Holocaust survivors through cross-country comparisons. A total of n = 248 OHS and n = 240 GHS from Israel, Germany, and the US completed a cross-sectional online survey on experiences of anti-Semitism, psychological distress, and posttraumatic stress symptoms, offered in English, German, and Hebrew. Psychological distress was significantly higher among participants from Germany vs. Israel and the US. Significant differences in experiences of anti-Semitism were found between the generations, with higher rates in GHS. Experiences of anti-Semitism were found to be associated with a higher risk for psychological distress and probable posttraumatic stress disorder (PTSD). The study emphasises the severe psychological stress being associated with experiences of anti-Semitism among OHS and GHS across different countries of origin. Given the rise in anti-Semitism since October 7, 2023 onwards, the findings are a warning and a clear impetus for political authorities as well as civil society to strengthen efforts for better healthcare and protecting Jewish life worldwide.
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