Hydrogen has become more and more accepted as a key component in the transition to cleaner energy systems since it provides a high energy output without producing carbon on site. Although this is a potential, the majority of hydrogen is produced through fossil-based processes. Low-carbon hydrogen production pathways such as water electrolysis are increasingly attracting attention; however, their large-scale deployment is influenced primarily by electricity demand, system efficiency, and water quality requirements rather than bulk water consumption itself. Even more clean production paths like electrolysis are usually reliant on high-quality freshwater, particularly in proton exchange membrane (PEM) systems where high-purity feedwater is necessary to prevent membrane degradation and catalyst poisoning. Although the actual water consumption associated with electrolysis is relatively modest compared with many industrial processes, there is a shift in focus to use of alternative water sources to improve resource circularity and reduce dependence on high-purity freshwater in water-stressed regions. The concept of all water to hydrogen is to combine water treatment with hydrogen production enabling the use of various forms of water as a clean energy feedstock. This will not only alleviate pressure on freshwater resources, but also encourage the use of wastewater in a circular economy structure. In this aspect, freshwater, seawater, wastewater, and grey water are all under consideration as means of producing hydrogen. This review examines the connection between water and hydrogen generation, highlighting the necessity to shift towards systems that are not based on freshwater and focus on less utilized and more accessible water resources. The review further emphasizes that the dominant techno-economic challenge in electrolysis remains the high energy requirement associated with water splitting, while water quality mainly affects electrolyser durability and long-term operational stability. There is an indication that given the right pre-treatment techniques, long-lasting materials to stop corrosion, and enhanced electrochemical technologies, various water sources can be utilized successfully to generate hydrogen. Production of hydrogen using saline and wastewaters is also a viable path forward in solving the energy and water crises at the same time. This article unites the latest advancement and technology that contribute to the idea of All Water to Hydrogen. Its unique contribution is its analysis of various water sources in one framework in particular, the wastewater systems, their treatment requirements, performance efficiency, and scaling-up factors. The review offers a clear way to apply this concept to the real-world applications by linking hydrogen production and sustainable water management.
The accelerating demand for high-performance energy storage systems, driven by renewable energy integration and the electrification of transportation, necessitates the development of next-generation batteries with higher energy density, enhanced safety, and long-term stability. Among various anode materials, transition-metal oxides (TMOs) and transition-metal sulfides (TMSs) have emerged as two highly promising families due to their structural versatility, abundant redox-active centers, and cost-effective synthesis. TMOs, such as MnO2 and Fe2O3, offer high theoretical capacities and chemical robustness but are hindered by poor electronic conductivities and sluggish ion transport. In contrast, TMSs, such as FeS2 and VS2, exhibit superior electrical conductivity, multielectron redox activity, and high energy density; however, they suffer from severe polysulfide dissolution, large volume expansion, and interfacial instability. This review provides a comprehensive comparison of TMOs and TMSs in terms of their electrochemical performance, synthesis strategies, and structural evolution during cycling. Furthermore, it highlights recent advances in structural engineering techniques, such as high-entropy strategies, defect modulation, and crystal facet engineering, that address their intrinsic limitations. Finally, emerging research directions and green synthesis strategies are discussed, offering a critical perspective on the future design of oxide- and sulfide-based anodes for high-performance lithium- and sodium-ion batteries.
Urea is a common nitrogenous pollutant in agricultural and industrial wastewaters, and its electrochemical oxidation in alkaline media enables simultaneous detoxification and energy recovery. Herein, we report an interface-engineering strategy based on P,N-modified nickel-carbon nanofibers prepared via a scalable electrospinning-carbonization process using ammonium phosphate as a multifunctional precursor. During thermal treatment, phosphorus and nitrogen heteroatoms are incorporated into the carbon framework while regulating the surface chemistry of embedded nickel nanoparticles, promoting the formation of a NiOOH-ready interfacial layer. Structural analyses (XRD, SEM/TEM) confirm the formation of metallic Ni domains uniformly dispersed within turbostratic carbon nanofibers. XPS reveals the coexistence of Ni0/Ni+2/Ni+3 species along with phosphate- and nitrogen-derived functionalities that enhance electronic modulation and redox reversibility. In 1.0 M KOH, the optimized composition exhibits a Ni+2/Ni+3 redox charge of ~12.5 mC.cm-2. For urea electrooxidation (0.5 M urea), the catalyst delivers a maximum current density of ~115 mA.cm-2 with a low onset potential of 0.37 V (vs Ag/AgCl). The apparent activation energy is 9.82 kJ.mol-1, indicating a kinetically favorable NiOOH-mediated pathway. Chronoamperometry shows stable operation with ~70-80% current retention over 1000 s. When implemented as an anode in a membrane-less direct urea fuel cell, the material achieves a peak power density of ~1.1 W.m-2 at 35 °C, demonstrating practical wastewater-to-energy feasibility. This work highlights how dual heteroatom modification of carbon nanofibers can regulate nickel interfacial chemistry, enabling efficient urea remediation coupled with renewable power generation.
Gait asymmetry is a common manifestation of walking impairment among clinical populations. We recently developed a novel treadmill walking approach called 'dynamic treadmill walking' that can provide asymmetric gait training by changing the treadmill speed between 'fast' and 'slow' speeds within a single stride. Here, we studied the energy expenditure associated with a variety of dynamic treadmill walking conditions. We hypothesized that the metabolic power required for dynamic treadmill walking in all conditions would approximate the metabolic power associated with conventional walking at the mean of the fast and slow speeds employed in the task. Eleven young adults without gait impairment walked on an instrumented treadmill and breathed into a metabolic measurement system. During dynamic treadmill walking, the treadmill fluctuated between 0.75m/s and 1.50m/s, each for 50% of an individual's stride time. We used a metronome to synchronize participants' right heel-strikes with four different timing conditions. Net metabolic power during dynamic treadmill walking was significantly greater than normal walking at the mean speed of the task (1.125m/s) and generally lower than walking at the fast speed (1.5m/s). We did not observe any significant associations between net metabolic power and several measures of gait asymmetry during dynamic treadmill walking. These findings establish dynamic treadmill walking as a promising technique for improving gait symmetry in individuals who cannot tolerate fast treadmill walking, a common gait rehabilitation approach. Future work will assess the feasibility, metabolic demands, and clinical efficacy of using dynamic treadmill walking to improve gait symmetry in clinical populations. Dynamic treadmill walking (i.e., walking with oscillating treadmill speeds) has previously been shown to drive gait asymmetries, but little is known about the energy expenditure required to complete the task.Our hypothesis was that dynamic treadmill walking would have similar metabolic power requirements to normal walking at a speed that is intermediate between the two dynamic treadmill walking speeds.We found that dynamic treadmill walking actually requires metabolic power that is greater than the average of the two belt speeds, but less than that used for fast walking.Dynamic treadmill walking is a promising and clinically translatable technique for rehabilitating populations with gait asymmetries that is not more energetically costly than fast treadmill walking, a common gait rehabilitation approach.
This study investigated whether seasonal categories affect airborne mercury concentrations in the U.S. Department of Energy operations. We conducted an initial assessment of the general variability of airborne elemental mercury time-weighted average (TWA) samples. Then, we performed a two-component time series analysis to determine whether long-term, cyclical temperature change patterns affect mercury concentrations. Both ARIMA time series models demonstrated stationary, non-random means (χ² = 83.8, p < 0.001) and standard deviation (χ² = 55.8, p < 0.001) of mercury concentrations. Our results indicate that the seasonal factors did not influence mercury concentration. Our results demonstrate that mercury concentrations primarily emanate from operational activities, work practices, and/or transient environmental conditions rather than seasonal fluctuations.
Background and objectives Weight-for-height (WHZ) and body mass index (BMI)-for-age (BAZ) are commonly used to assess child overnutrition but have limitations: they conflate skeletal growth with body weight, correlate with height, and inadequately distinguish fat from lean mass, particularly during puberty. This study proposes an India-specific generalised body mass index (gBMI), an age- and sex-specific power-type index adapted from Benn's concept, to better capture adiposity. Methods Exponent parameters for gBMI were estimated using healthy-child data, selected by WHO selection criteria, from the National Family Health Survey (NFHS-3,4,5) and the Comprehensive National Nutrition Survey (CNNS), comprising 12,466 children under 5 years and 6,487 aged 5-19 years. Polynomial regression to model age- and sex-specific variation in the weight-height relationship was used to estimate the exponents of height, and growth curves were generated using generalised additive models for location, scale, and shape (GAMLSS) with location scale and shape (LMS) methods. Validation employed independent data from 457 urban schoolchildren aged 5-16 years in Bengaluru, including fat and lean mass measured by dual-energy X-ray absorptiometry (DXA). Results The exponent varied with age (1.3 in infancy, ∼2.9 in pubertal boys, 2.7 in girls, stabilising at ∼2 in late adolescence). Unlike BMI, gBMI residuals showed near-zero correlation with height. gBMI-for-age Z-scores (gBAZ) showed lower wasting in children under 5 years (10.7% vs. 19.2% using WHZ) and higher adolescent overnutrition (8.7% vs. <1% using BAZ). Validation showed stronger association of gBAZ with body fat (r=0.70) than BAZ (r=0.65). Interpretation and conclusions The gBMI provides an adaptable, height-independent, and adiposity-sensitive index for assessing malnutrition and obesity in children and adolescents. Its use could refine nutritional surveillance and interventions, with potential wider applicability with longitudinal evaluations.
Hybrid structures, formed by joining organic and inorganic semiconductors, can harness the unique photophysical properties of each material to achieve new functionality. In these hybrid systems, the interface between disparate materials must be carefully structured to dictate the properties of the whole. When exciton transfer between materials is the goal, the interface must be crafted to promote electronic coupling between the energy-donating and -accepting layers. Here, we study how covalent attachment of anthracene to a Si(111) surface influences the molecular and electronic structure of the molecule-solid interface. Using a combination of density functional theory (DFT) geometry optimizations and Born-Oppenheimer molecular dynamics (BOMD), we find anthracene molecules twist and distort after bonding to the silicon surface, lowering their symmetry and widening their HOMO-LUMO gap by approximately 160 meV. Electronic sum frequency generation (ESFG) measurements of anthracene-functionalized Si(111) surfaces identify anthracene-associated electronic resonances that are blue-shifted relative to the linear absorption features of anthracene in solution, supporting the predictions. These findings highlight the critical role of molecular distortion in tuning electronic properties at hybrid interfaces, offering insight into the design of functional organic/inorganic materials for optoelectronic applications.
Aluminum nitride (AlN) is an ultrawide-bandgap semiconductor whose large intrinsic band gap limits low-energy interband optical absorption. This work compares Ce substitution at the Al site, C substitution at the N site, and Ce-C co-substitution in wurtzite AlN to clarify how Ce 4f/5d states and C 2p states modify the local structure, band-edge electronic states, and optical response. Among five neutral CeAl-CN configurations considered in a 2 × 2 × 2 supercell, the nearest-neighbor Ce-C pair has the lowest total energy, with the other configurations lying 6.6-17.7 meV higher. The selected Ce-C pair also has a negative binding energy of -3.26 eV relative to the corresponding isolated single-substitution reference supercells. Structural relaxation shows lattice expansion after substitution, with the largest volume increase of 7.93% obtained for AlN:Ce-C. The calculated band gap of intrinsic AlN is 4.19 eV, whereas the effective electronic gaps of AlN:C, AlN:Ce, and AlN:Ce-C are 3.59, 2.18, and 2.04 eV, respectively. Since AlN:Ce-C is only 0.14 eV smaller in effective gap than AlN:Ce, the role of Ce-C co-substitution is interpreted mainly through defect-pair energetics, orbital redistribution, and local population changes rather than as a large additional band-gap narrowing. DOS/PDOS and population analyses show that C 2p states mainly modify the occupied valence-edge region, Ce 4f/5d states contribute near the band-edge and conduction-band regions, and Ce-C co-substitution induces finite spin population on C together with a nonzero Ce-C bond population. The scissors-corrected optical spectra show increased low-frequency dielectric and refractive responses, with ε₁(0)/n(0) changing from 3.805/1.951 for intrinsic AlN to 4.449/2.109 for AlN:Ce-C, while AlN:C gives the largest low-frequency values of 4.530/2.128. Additional low-energy interband absorption and attenuation features appear especially in AlN:C and AlN:Ce-C, associated with defect-related transitions involving C 2p and Ce-related states. These changes are interpreted as calculated interband optical-response redistribution within the present neutral-defect supercell framework, not as direct evidence of device-level optoelectronic performance. First-principles calculations were performed using the CASTEP module in Materials Studio. The exchange-correlation interaction was described using the generalized gradient approximation with the Perdew-Burke-Ernzerhof functional, and on-the-fly-generated ultrasoft pseudopotentials were employed. Intrinsic AlN, AlN:Ce, AlN:C, and AlN:Ce-C were constructed from a fully relaxed 2 × 2 × 2 wurtzite AlN supercell containing 32 atoms. Single-doped models were constructed by replacing one Al or one N atom, corresponding to 6.25% substitution on the relevant sublattice. The co-doped model contains one CeAl-CN pair, corresponding to xCe = yC = 0.0625 in Al1-xCexN1-yCy, or a combined sublattice substitution level of 12.5%. A plane-wave cutoff energy of 700 eV and a 4 × 4 × 3 k-point mesh were used. Intrinsic AlN was calculated using non-spin-polarized GGA-PBE, C-doped AlN using spin-polarized GGA-PBE, and the Ce-containing systems using spin-polarized GGA-PBE + U. A Hubbard U correction of 5 eV was applied only to the Ce 4f orbitals. Band structures, TDOS/PDOS, Mulliken and Hirshfeld population analyses, representative bond populations, and optical properties were calculated. The dielectric function, complex refractive index, absorption coefficient, and reflectivity were obtained within the linear-response framework using a 2.01 eV scissors correction only for optical-property calculations.
Achieving highly reversible Na plating/stripping is crucial for the stable operation of low-temperature anode-free sodium metal batteries (LT-AFSMBs), yet simultaneously realizing ultra-high Coulombic efficiency (CE) and long-term durability, accompanied by high energy density, remains a formidable challenge. Herein, by regulating the molecular side chain, we design an asymmetric chain-like ether solvent that elegantly balances weak Na+-dipole and strong anion-dipole interactions. This rationally tailored electrolyte fosters an anion-rich Na+ coordination environment, which significantly lowers the desolvation barrier and drives the formation of a robust, anion-derived solid electrolyte interphase with rapid interfacial dynamics. Consequently, the optimized electrolyte delivers an unprecedented average CE of 99.96% over 500 cycles at -20°C. Remarkably, even under stringent conditions of an ultra-high cathode loading (28.05 mg cm-2) and areal capacity (2.48 mAh cm-2), the LT-AFSMBs retain 85.9% of their initial capacity over 600 cycles at -20°C. Moreover, practical Ah-level anode-free pouch cells demonstrate stable operation for 300 cycles, yielding a high energy density exceeding 200 Wh kg-1 (based on the mass of entire pouch cell). This paradigm-shifting solvation strategy provides a highly viable and scalable blueprint for the next-generation, extreme-temperature energy storage systems.
Cancer cells alter their metabolism to support growth and survival, most notably by fermenting glucose to lactate even in the presence of oxygen, a phenomenon known as the Warburg effect. Although this metabolic state has been recognized for decades, its bioenergetic advantages remain unclear, as fermentation produces less net ATP than mitochondrial respiration. How aerobic fermentation contributes to cellular energy balance therefore remains unresolved. Here, we show that extracellular acidification generated by lactate export creates a proton gradient across the plasma membrane that is harnessed by ectopic ATP synthases to drive intracellular ATP production. We find that ATP synthase and proton-shuttling components of the mitochondrial respiratory chain translocate to the plasma membrane in cancer cells and are preferentially oriented to exploit this gradient, linking a hallmark of aerobic fermentation directly to energy supplementation. This work provides a mechanistic resolution to the apparent energetic inefficiency of the Warburg paradigm and identifies a previously unrecognized pathway for energy complementation in cancer.
The construction of supramolecular assemblies with hierarchical chirality provides a new platform for exploring the chirality-induced spin selectivity (CISS) effect. In this work, we systematically investigate CISS in multichiral systems using a class of multilayer helical architectures. Each layer consists of stacked helical rings with well-defined local chirality. By introducing controlled interlayer twisting, a global helical handedness is imposed, forming tubular multichiral helices. Including geometric spin-orbit coupling and dephasing in our theoretical model, we find that the interplay of local and global chirality leads to enhanced magnetoresistance (MR) and the simultaneous appearance of transverse and longitudinal CISS signals. We also examine two common approaches for including dephasing. Self-consistent Büttiker voltage probes preserve charge current conservation in the two-terminal subspace and yield zero linear MR. Leakage dephasing produces finite linear MR but only by breaking two-terminal current conservation. Neither method alone provides a fully self-consistent explanation for two-terminal linear CISS MR. More generally, when the self-energy satisfies a generalized time-reversal condition, global Onsager reciprocity is maintained. Beyond this condition, a genuine linear MR requires a reciprocity-breaking mechanism that is both charge-conserving and linked to molecular chirality. The dual-chiral geometry breaks the symmetry of single helices and induces an anomalous angular phase shift in MR. In addition, Floquet analysis shows that the interplay between local and global chirality enables controlled switching of spin polarization under circularly polarized light. These results establish a fundamental framework for understanding CISS in multichiral superstructures and provide design principles for integrated spin, optical, and magnetic control in multichiral spintronic devices.
Iron fluoride is a promising conversion-type cathode for lithium-ion batteries owing to its high theoretical energy density, yet its practical application is hindered by poor electronic conductivity and limited cycling stability. Here, we report a synergistic strategy that integrates cobalt doping with binder engineering to simultaneously enhance the electronic structure and Li+ transport kinetics of FeF3 cathodes. Cobalt incorporation modulates the Fe─F coordination environment, introduces defect sites, and redistributes charge density, thereby promoting electron transport and Li+ diffusion. In parallel, a sodium alginate-based graphene oxide (SAGO) binder with high ionic conductivity reduces interfacial resistance and facilitates ion transport. As a result of this dual modulation, the SAGO-Co-FeF3 cathode delivers a reversible capacity of 356 mAh g-1 after 50 cycles at 0.2 C and maintains 132 mAh g-1 at 10 C. Comprehensive electrochemical measurements, kinetic analyses, in/ex situ characterizations, and density functional theory calculations elucidate the underlying enhancements in electronic and ionic transport. Notably, a full cell employing the SAGO-Co-FeF3 cathode retains 86.5% of its initial capacity after 500 cycles. This work provides a generalizable strategy for designing high-energy, long-life conversion-type cathodes for practical lithium-ion batteries through coupled electronic and interfacial engineering.
Semi-natural grasslands (SNGs) are biodiversity-rich cultural landscapes maintained through conservation-driven mowing and grazing, generating recurrent streams of heterogeneous lignocellulosic biomass. Although this biomass represents a potential resource within a circular bioeconomy, its late harvest timing, elevated ash and mineral contents, high botanical variability and dispersed spatial distribution fundamentally differentiate it from woody biomass and intensively managed energy crops. Here we provide a critical synthesis of ecological constraints, technological valorisation pathways and techno-economic evidence for SNG biomass utilisation across Europe. By integrating technology readiness level (TRL) analysis with techno-economic assessment (TEA), we show that technical maturity alone is an insufficient indicator of practical suitability. Generic TRL classifications frequently overestimate applicability because they do not account for feedstock-specific constraints inherent to conservation-derived biomass. Across the reviewed literature, economic feasibility consistently emerges only for integrated, low-complexity energy pathways-most notably co-digestion in existing anaerobic digestion systems and fractionation-based concepts such as IFBB-where infrastructural integration, mineral reduction and multi-output recovery mitigate feedstock heterogeneity. In contrast, stand-alone bioenergy facilities and advanced biorefinery routes remain economically marginal or insufficiently assessed. We argue that feedstock-sensitive systems analysis, regional aggregation and coherent policy alignment between biodiversity conservation and bioeconomy strategies are essential to transform SNG biomass from a management by-product into a structurally viable component of a multifunctional bioeconomy.
Catheter ablation is the mainstay of rhythm control in atrial fibrillation (AF), and its use is steadily increasing worldwide. To optimize procedural safety and efficacy, an appropriate sedation or anesthesia regimen is essential, ensuring adequate analgesia and a stable respiratory pattern while minimizing patient movement. However, the optimal sedation strategy remains a matter of debate, with approaches ranging from general anesthesia to deep or conscious sedation. Since anesthesiologists administer general anesthesia, attention focuses on hypnotics, defined as drugs that induce and/or maintain sleep by depressing the central nervous system, and analgesics. In many centers, these agents are administered by electrophysiology laboratory staff in accordance with local regulations and institutional protocols, which vary among countries. This warrants caution, as individual responses to commonly combined agents are unpredictable and may result in deeper-than-intended sedation. Therefore, respiratory or hemodynamic support may become necessary in selected patients. Notably, protocols incorporating hypnotic communication have also been proposed and implemented. The selection of sedation and analgesia strategies for AF ablation has become increasingly important for balancing patient safety, procedural effectiveness, and resource utilization. The approach should be individualized based on patient characteristics, procedural complexity, energy source, institutional resources, and the relevant national regulatory framework.
Multiple acyl-CoA dehydrogenase deficiency (MADD) is a mitochondrial lipid storage myopathy characterized by impaired fatty acid β-oxidation, mitochondrial dysfunction, and progressive neuromuscular and cardiac disease. MADD is most commonly caused by pathogenic variants in electron transfer flavoprotein dehydrogenase (ETFDH), which encodes electron transfer flavoprotein-ubiquinone oxidoreductase (Etf-QO), a critical redox enzyme that transfers electrons from acyl-CoA dehydrogenases to the mitochondrial electron transport chain. Defective Etf-QO activity disrupts electron flow, promotes reactive oxygen species (ROS) production, and impairs cellular energy metabolism, linking abnormal lipid oxidation to oxidative stress-mediated tissue damage. To investigate the role of redox imbalance in MADD pathogenesis, we generated CRISPR/Cas9 knock-in Drosophila melanogaster models carrying patient-relevant Etf-QO missense mutations (L127R, S296C, and L399F; corresponding to human L138R, S307C, and L409F) within conserved FAD- and ubiquinone-binding domains. Mutant flies developed progressive locomotor impairment, reduced muscle performance, and marked lipid droplet accumulation in skeletal muscle, cardiac tissue, and fat bodies, indicating systemic defects in mitochondrial lipid utilization. Cardiac analyses demonstrated reduced fractional shortening, prolonged heart period, and increased arrhythmia index, consistent with metabolic cardiomyopathy associated with mitochondrial oxidative stress. In vivo respirometry revealed significantly decreased oxygen consumption, reflecting impaired oxidative phosphorylation. At the molecular level, mutant flies exhibited elevated ROS levels and ATP depletion, accompanied by increased expression of AMPK, PGC-1α, and Tfam, suggesting activation of energy stress signaling and compensatory mitochondrial biogenesis. Importantly, endurance exercise significantly improved locomotor and cardiac function while reducing lipid accumulation and oxidative stress. Together, these findings establish a redox-centered in vivo model of MADD and identify oxidative stress as a major driver of disease pathology and a potential therapeutic target.
The electrocatalytic oxidation of biomass-derived alcohols has emerged as a sustainable route for green hydrogen production, offering a compelling alternative to conventional water electrolysis by replacing the energy-intensive oxygen evolution reaction with thermodynamically more favorable alcohol oxidation reactions. However, the practical application of this technology faces a critical scientific challenge arising from the competition between C-C bond retention and cleavage pathways. The cleavage pathway generates low-value products (e.g., formic acid, CO2) and causes severe catalyst poisoning due to carbon-containing intermediate adsorption, whereas the retention pathway yields high-value aldehydes, ketones, or carboxylic acids. Achieving highly selective C-C bond retention is therefore essential for realizing the synergistic benefits of energy savings and product valorization. This review systematically explores recent research advances in selective alcohol oxidation to high-value chemicals, with an emphasis on the mechanism of C-C bond cleavage or retention pathways, as well as catalyst design based on noble metal materials. These design strategies collectively provide a solid foundation for achieving highly selective C-C bond retention in alcohol electrooxidation. With further advancements in this field, alcohol oxidation-assisted hydrogen production technology is expected to play an increasingly important role in future green hydrogen systems and biomass refining, contributing to the transition toward a sustainable and low-carbon chemical industry.
Formate dehydrogenases catalyze the reversible two-electron interconversion of formate and carbon dioxide and generally are assumed to operate through metal-centered redox chemistry at their molybdenum or tungsten active sites. The enzymes also are thought to possess a terminal sulfido ligand which is expected to play a central role in the catalytic mechanism. Here, we investigate the molybdenum-containing formate dehydrogenase FdsDABG from Cupriavidus necator using a combination of Mo K-edge X-ray absorption spectroscopy (XAS), high-energy-resolution fluorescence-detected (HERFD) XAS, extended X-ray absorption fine structure analysis (EXAFS), and density functional theory (DFT) calculations. We observe only subtle spectroscopic changes upon reduction of the oxidized enzyme by formate, suggesting that redox chemistry does not involve the metal; moreover, EXAFS analysis shows no evidence for a terminal sulfido ligand in the oxidized enzyme. DFT calculations support these findings and suggest that the oxidized enzyme possesses a cysteine persulfido structure, which is reduced by cleavage of the S-S bond to form an Mo-SH species, leaving the formal oxidation state of molybdenum unchanged. Collectively, these results suggest that the catalytic reaction of formate dehydrogenases involves ligand-based redox chemistry at a metal center formally reduced to the Mo(IV) state in the oxidized enzyme.
Coupled-cluster theory provides an accurate description of electronic ground and excited states. While it has been rigorously established that the coupled-cluster ground state energy is size extensive and local excitations are size intensive in the thermodynamic limit, the separability of other properties in coupled-cluster theory is subject to known limitations. In particular, it was shown [Stanton, J. Chem. Phys. 1994, 101, 8928-8937] that multicenter two-particle density matrices are not asymptotically separable in general. In the present work, an analogous analysis is applied to the excitonic coupling of local excitations of two separate molecules, using both the equation-of-motion (EOM) and linear-response (LR) formalism. It is shown that for both formalisms the two-electron transition density associated with the excitonic coupling does not exactly separate into a product of local one-electron transition densities. Numerical examples are provided for Ne2, (CO)2, and (C2H4)2, using coupled-cluster expansions up to single, double, triple, and quadruple excitations (CCSDTQ). Small but noticeable deviations on the order of 5-10% are reported for approximations like CCSD and its second-order approximate variant CC2. As soon as triple excitations are included, the separability error becomes significantly smaller. Exploratory computations for the coupling of larger chromophores such as perylene or cumarine dyes using the CC2 method indicate that the separability error can grow up to orders of 20%. While these deviations are typically below the error margin of this method, the separability error could be of relevance in the design and benchmarking of local coupled-cluster approaches for excited states.
Li-S batteries (LSBs) are seen as a promising new-generation energy storage technology owing to their high theoretical energy density and economy. However, their practical use is still limited by the shuttle effect of lithium polysulfides (LiPSs) and slow reaction kinetics. Here, a unique fish-scale-like, phosphorus-doped carbon nanosheet-supported NiSe2-CoSe2 heterojunction (NiSe2-CoSe2/PC) was designed and synthesized as a functional interlayer for LSBs. The hierarchical porous architecture, together with the fish-scale-like surface, offers a high surface area (324.1 m2 g-1) and plenty of active sites, which substantially enhance the physical confinement and chemical anchoring toward LiPSs. Combined with the synergistic catalytic effect of the heterojunction, the NiSe2-CoSe2/PC coating on the polypropylene (PP) separator facilitates the electrochemical conversion of LiPSs and curbs undesired shuttling. Electrochemical tests show that the LSB with this modified separator retains a capacity of 517.6 mA h g-1 after 500 cycles at 2.0 C, with a capacity loss of only 0.079% per cycle, and also delivers a discharge capacity of 779.8 mA h g-1 at 3.0 C. Even under a high sulfur loading of 3.1 mg cm-2, the LSB maintains a consistent capacity of 526.1 mA h g-1 over 200 cycles at 0.2 C.
Magnetic nanoparticle heating (MNH) enables nanoscale energy delivery, yet current predictions of nonequilibrium magnetic dynamics at the single-particle level often lack quantitative experimental validation across nanoparticle regimes and field conditions. Here, we combine experimentally derived composite magnetic anisotropy with a stochastic Landau-Lifshitz-Gilbert description to quantitatively model MNH across superparamagnetic and magnetically blocked ferrimagnetic regimes. Simulations reproduce macroscale calorimetric heating measurements across broad particle sizes and field conditions while revealing how cycle-resolved stochastic magnetic switching contributes to heat generation. This approach shows how stochastic thermal fluctuations and anisotropy-governed dynamics give rise to classical hysteresis behavior at the macroscale, providing a multiscale physical framework for modeling energy dissipation in complex magnetic nanomaterials.