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Adaptation of burn care accreditation standard
Finite element analysis of different methods for uprighting partially impacted mandibular second molars
Site-specific oral microbiome profiles in healthy young Korean women
Constrained RNA polymerase mutational pathways distinguish corallopyronin A resistance from rifampicin resistance in staphylococci
Abstract Corallopyronin A (CorA) is a natural RNA polymerase (RNAP) inhibitor active against Gram-positive pathogens, including Staphylococcus aureus . Although spontaneous resistance to CorA occurs less frequently than to rifampicin, the genetic basis and evolutionary constraints of CorA resistance remain incompletely defined. Spontaneous mutation frequencies to CorA and rifampicin were determined by fluctuation analysis in three S. aureus strains and two coagulase-negative staphylococci (CNS). Resistant mutants were phenotypically characterized and subjected to whole-genome sequencing. Double-resistant mutants were generated under rifampicin selection. Fitness costs were assessed by direct competition assays. Mutation frequencies to CorA were consistently lower than to rifampicin across all tested strains (Rif/CorA ratios 2.3–2.7). Whole-genome sequencing of 41 independently derived CorA-resistant mutants revealed resistance-associated substitutions confined to the RNAP subunits RpoB and RpoC. The mutational landscape was highly restricted, with recurrent hotspots at RpoC K334 and RpoB S1127. In coagulase-negative staphylococci (CNS), resistance remained RNAP-centred but displayed broader allelic diversity, including substitutions previously described in S. aureus but identified here for the first time in CNS species, as well as the previously undescribed RpoC D810Y substitution. Ten mutants with resistance to CorA and rifampicin retained the CorA-associated mutation and acquired additional rifampicin resistance substitutions at non-overlapping RNAP residues. CorA resistance imposed a moderate fitness cost (12–15%), while additional rifampicin resistance resulted in mutation-dependent increases in the fitness burden. CorA resistance in staphylococci arises at lower spontaneous frequencies than rifampicin resistance and is mediated by a constrained set of RNAP mutations. The restricted mutational landscape and associated fitness costs indicate that, under the in vitro conditions examined, CorA resistance arises through more constrained evolutionary pathways than rifampicin resistance. These findings provide a foundation for further evaluation of CorA as an RNA polymerase-targeting antimicrobial.
Rational Design of the Composite Perfluoro-Sulfonic Ionomer for High-Performance Proton Exchange Membrane Fuel Cells
Abstract Scaling proton exchange membrane fuel cells (PEMFCs) is constrained by high cathodic overpotential and platinum usage for the oxygen reduction reaction, challenges exacerbated by catalyst poisoning from perfluorosulfonic acid (PFSA) ionomers. Though compositing PFSA with additives can mitigate this poisoning, progress has remained largely empirical due to the lack of quantitative assessment tools. Here, we introduce an electrochemical probe leveraging ionomer-coated single-crystal Pt(111) to quantify the coverage and strength of PFSA adsorption, elucidating how cationic additives suppress Pt poisoning. We identify an inverse correlation between cation hydration energy and PFSA adsorption, guiding the rational design of a poorly hydrated tetramethylammonium-anchored covalent organic framework (TMA+-COFs) as an ionomer additive. Electrochemical and spectroscopic analyses reveal that the composite TMA+-COFs/PFSA layer significantly inhibits sulfonate adsorption and poisoning onto Pt(111) through robust electrostatic interactions, which translates to a 1.7- and 4-fold activity enhancement for industrial Pt/C in rotating-disk and gas-diffusion electrodes, respectively. We also demonstrated a high mass activity of 1.08 A mgPt–1 in a PEMFC cathode with TMA+-COFs. Our work provides an alternative avenue to conventional catalyst engineering through the rational design of advanced composite ionomers for high-performance, low-Pt PEMFCs.
Robust Android malware detection through EfficientNet–BERT fusion and Jaya optimization for behavioral analysis
Ti3+-O Acid–Base Pairs for Efficient Solar-Driven Photothermal Nonoxidative Ethane Dehydrogenation
Abstract Nonoxidative ethane dehydrogenation (NOEDH) is a carbon efficient but thermodynamically severe route for ethene production. Solar-driven NOEDH offers a promising alternative, yet achieving both high activity and high ethene selectivity over noble metal-free catalysts without external heating remains unresolved. Here, we reported that Ti3+-O acid–base pairs on reduced rutile TiO2 enabled highly efficient full-spectrum solar-driven photothermal NOEDH without any external heating. The optimally reduced TiO2 at 750 °C delivered an ethene production rate of 392.0 mmol g–1 h–1, which was 1107 times higher than that of pristine TiO2 without reduction pretreatment. The high activity with a C2H4 selectivity of 94.9% surpassed the thermodynamic equilibrium limit and outperformed previously reported systems. Comprehensive characterizations identified surface Ti3+ sites adjacent to lattice oxygen as Lewis acid–base pairs that enhanced light absorption, promoted charge carrier separation, and directly participated in the C–H bond cleavage. Photogenerated electrons also preferentially accumulated on the coordinatively unsaturated Ti3+-O sites, which weakened ethene adsorption, thereby accelerating product desorption and suppressing deep dehydrogenation and coke formation. The synergy between photogenerated hot carriers and localized photothermal heating lowered the apparent activation energy from 157.6 kJ mol–1 in the dark to 75.0 kJ mol–1 under illumination. This work establishes surface acid–base pairs on noble metal-free catalyst as a powerful platform for sustainable light-driven alkane upgrading.
DWSM: an EEG digital watermark generation and black-box authentication method based on wavelet transform and statistical hypothesis testing
Total Synthesis of Benthol A: Evidence for a Structure Revision
Abstract Benthol A, a dinoflagellate-derived polyol/polyether marine natural product endowed with potent antimalaria and appreciable antiviral activity, consists of a 72 C atom linear backbone featuring 35 stereogenic centers and four stereogenic alkenes. The constitution and configuration of this intriguing “super-carbon-chain compound” had been assigned by the isolation team by a combination of spectroscopic, chemical, and computational means. Outlined in this and the accompanying paper is the first total synthesis of this challenging target, which came along with a subtle structure revision. During the synthesis of the building blocks, a spectral irregularity was noticed in that the 13C NMR chemical shifts as well as some of the 3JH,H coupling constants of the synthetic samples deviated notably from the data reported for the entire C31–C41 region of benthol A corresponding to the tetrahydropyran E-ring and its vicinity. A systematic approach made it possible to narrow down the likely site of error to a single, incorrectly assigned stereocenter, i.e., the C40 position; interestingly, the configuration of this site had been determined by the isolation team solely by computational means. In chemical terms, our studies showed how the proper choice of a propargylic protecting group allows the regiochemical course of a gold-catalyzed spiroacetalization reaction to be steered. Moreover, carbonyl homologation by the addition of a highly functionalized but entirely unstabilized diazo derivative generated in situ to an equally highly functionalized aldehyde proved adequate for the coupling of elaborate building blocks (Buchner–Curtius–Schlotterbeck reaction).
Reducing circuit resources in Grover’s algorithm via constraint-aware initialization
Abstract Grover’s search algorithm provides a quadratic speedup over classical brute-force methods for unstructured search problems in terms of query complexity and is widely used as a versatile subroutine in numerous quantum algorithms, including those for combinatorial problems with large search spaces. For such problems, it is natural to reduce the effective search space by incorporating problem constraints at the initialization step, which in Grover’s algorithm can be achieved by preparing structured initial states that encode constraint information. In this work, we present a systematic framework with a simple preprocessing procedure for constraint-aware initialization in Grover’s algorithm, focusing on problems with linear constraints. The proposed framework incorporates cardinality constraints and parity constraints extracted from more general linear constraints. While such structured initial states can reduce the number of oracle queries required to obtain a solution, their preparation incurs additional circuit-level costs. We therefore offer a conservative circuit-level resource analysis, showing that the resulting constraint-aware initialization can improve resource efficiency in terms of gate counts and circuit depth. The proposed framework is further illustrated numerically using the exact-cover problem as a representative application. Overall, our results indicate that this approach serves as a practical baseline for achieving more resource-efficient implementations of Grover’s algorithm compared to the standard uniform initialization.
Accelerated Self-Photopolymerization of Phenolics in Microdroplets Contributes to the Brown Carbon Formation
Abstract While phenolic compounds are recognized as key atmospheric precursors of brown carbon (BrC), the mechanisms governing their interfacial transformation into BrC aerosols, particularly at the microdroplet air–water interface (AWI), remain incompletely characterized. This study investigated the photolysis of phenolic compounds in microdroplets under UV irradiation, revealing a transformation efficiency 2 orders of magnitude higher than that in bulk solutions. Through integrated Fourier transform ion cyclotron resonance mass spectrometry, liquid chromatography–mass spectrometry, and fluorescence excitation–emission matrix spectrum, we identified interfacial-confined oligomerization as the dominant pathway generating BrC with oligomer characteristics. Multiscale theoretical simulations unveiled that the AWI functions as a key mediator through a synergistic mechanism: it not only drives the spontaneous accumulation of phenols at the interface, but also enhances their photon absorption efficiency via asymmetric interfacial H-π hydrogen bonding, as evidenced by a critical 24.7% increase in the molar extinction coefficient at 298 nm. Together, these dual effects synergistically facilitate photon capture and subsequent phenoxy radical generation. Our results establish the AWI as photochemical nanoreactors that fundamentally alter atmospheric BrC formation kinetics, providing a mechanistic framework to reconcile field observations of rapid aerosol aging under humid conditions, while challenging current model assumptions about phenolic transformation time scales.
Numerical investigation of cyclic damage and deterioration in rock mass under strong mining tremor disturbances at intermediate strain rates
Deciphering the Specificity of Reversible DNA-Phosphate ADP-Ribosylation via the Precise Synthesis and Enzymatic Profiling of Nucleotide-Phospho-ADP-Ribosyl Probes
Abstract ADP-ribosylation (ADPr), long recognized as a canonical protein post-translational modification, has recently expanded to include targeting nucleic acids, uncovering a diverse landscape of noncanonical biological functions. Emerging evidence suggests that ADPr at the 5′-phosphate terminus of DNA is implicated in the DNA damage response, yet understanding its precise molecular function has been hampered by the lack of structurally defined chemical probes. Here, we report the stereoselective synthesis of deoxynucleotide-phospho-ADPr (dN-P-ADPr) probes, representing native fragments of terminal DNA-ADPr. Our strategy leverages a mild, stereocontrolled glycosylation to construct the challenging ribosyl-phosphate linkage, followed by P(III)–P(V) coupling to establish the pyrophosphate bridge. This robust toolkit enabled the systematic biochemical profiling of DNA-ADPr hydrolases across diverse kingdoms of life. Remarkably, using these newly developed probes, we uncover hydrolases across the diversity of life capable of reversing ADPr modifications at phosphorylated DNA ends. We further show that these enzymes exhibit an absolute preference for the native-like α-anomer, independent of the identity of the adjacent DNA nucleobase, suggesting that substrate recognition is governed primarily by the ADPr-phosphate linkages rather than the local nucleobase context. Together, these synthetic probes and biochemical insights provide an essential foundation for deciphering the biological landscape of noncanonical ADPr.
Enhancing gear shaping precision and reducing noise via DRL
Engineering Altermagnetic Transitions in Two-Dimensional Metal–Organic Frameworks via Chemical Symmetry Breaking
Abstract Altermagnets are symmetry-defined magnetic phases that combine momentum-dependent spin splitting with zero net magnetization, offering promising opportunities for spintronics. However, their realization is strongly constrained by rigorous symmetry requirements. Exploiting the shared antiparallel magnetic order and vanishing net magnetization between antiferromagnets and altermagnets, we propose a general chemically driven strategy based on asymmetric ligand modification to transform pristine two-dimensional antiferromagnetic metal–organic frameworks into altermagnetic candidates. Using chromium phthalocyanine (CrPc) as a proof-of-concept model, we show that asymmetric modification lowers the local site symmetry at magnetic Cr centers and generates momentum-dependent spin splitting and anisotropic spin densities, as revealed by first-principles calculations. Oxygen-modified CrPc derivatives further illustrate the chemical tunability of this symmetry-control principle. Our work expands the design space of organic altermagnetic candidates and establishes a chemically grounded route for engineering symmetry-governed magnetic functionality in reticular materials.
Synthesis of a dual-functional hydrazone-based cobalt complex as a catalyst for the cycloaddition of CO2 and radioactive iodine capture
Total Synthesis of Benthol A: The Nominal and the Actual Natural Product
Abstract The total synthesis of the dinoflagellate-derived “super-carbon-chain compound” benthol A rigorously confirmed what the analysis of one of the required building blocks had forecasted, namely that the configuration of the secondary −OH group at C40 had been misassigned by the isolation team as the only one of a total of 35 stereogenic centers decorating the backbone of this polyol/polyether derivative. This conclusion bears implications because the original assignment had been solely based on computational data, which had resulted in a remarkably high score of 99.93% that was ultimately misleading. The multiconvergent blueprint underlying the successful approach accounts for the fact that alongest linear sequence of 32 steps sufficed to reach this intricate marine natural product. The inherent flexibility should also empower future studies aiming at a detailed mapping of the pharmacophore of this compound endowed with significant antiplasmodial activity.
Distributed priority-aware multi-objective routing for reliable data delivery in LoRa-enabled UAV networks
Zero Indirect Band Gap and Flat Bands in a Niobium Oxyiodide Cluster Material
Abstract Explorative chemistry in a reaction system composed of NbI4, Li2(CN2), and Li2O has led to the discovery of a number of niobium oxyiodide cluster compounds. During this reaction, the formation of solid phases was detected alongside gaseous phases, resulting in a range of products with cluster cores of varying shapes. After several niobium oxyiodide cluster compounds have already been identified within this reaction system, two additional compounds, Nb6O3I15 and Nb11O6I24, are discovered and structurally characterized by single-crystal X-ray diffraction. Both structures are based on the butterfly-shaped, oxygen-capped niobium cluster [Nb4O], which is extended to larger cluster fragments. The [Nb4O] cluster core in Nb6O3I15 is extended by two [NbO] units to form a three-dimensional framework, and Nb11O6I24 contains two connected [Nb4O] units, which form chiral units within an antiferrochiral hexagonal packing of strings. The striking string-like character of Nb11O6I24 was investigated in terms of its electronic structure and properties. DFT calculations showed Nb11O6I24 to possess a zero indirect band gap, with a pair of 3-dimensional flat bands surrounding the Fermi level. These unusual features of the electronic band structure suggest the presence of strongly correlated intercluster singlet electron states, arising from the helical shape of the clusters, the hexagonal packing of the strings, and the delocalized nature of cluster electron wave functions.