Author Correction: The nature of ferromagnetism in the chiral helimagnet Cr 1/3 NbS 2
Abstract not provided.
36 MATERIALS SCIENCE↗
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Results for “NbS”
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DFT + DMFT study of the magnetic susceptibility and the correlated electronic structure in transition-metal intercalated NbS 2
Not Available
Park, Hyowon (ORCID:0000000246932415)↗
Giant anomalous Hall effect in quasi-two-dimensional layered antiferromagnet Co 1 / 3 NbS 2
Not Available
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Highly Tunable Magnetic Phases in Transition-Metal Dichalcogenide Fe 1 / 3 + δ NbS 2
Not Available
2-dimensional systems↗
Effectiveness of nature-based solutions to reduce flooding in Quad Cities Metro Area (QCMA) using SWMM-HEC based flood model
Nature-based solutions (NbS) have gained significant attention as strategies for addressing urban environmental challenges, particularly since the establishment of the UN Sustainable Development Goals (SDGs) for 2030. However, the current research on NbS for urban flood management lacks comprehensive methodological approaches for identifying suitable areas and evaluating their effectiveness across different urban settings. Here, this study attempts to fill this gap by proposing a methodological framework integrating multi-criteria analysis with a SWMM-HEC-based hydrologic and hydraulic (HH) model to assess the suitability of NbS for the Quad Cities Metro Area (QCMA), consisting of Davenport, Bettendorf, Moline, and Rock Island. Eight NbS options-green roofs, rain gardens, infiltration trenches, permeable pavements, vegetative swales, dry detention basins, retention ponds, and rain barrels/cisterns - were considered based on volumetric efficiency and runoff reduction efficiency. The study reveals that implementing the proposed NbS could have substantially reduced flood depths in key historical flood events by 21% in 1993, 15% in 2008, 16% in 2011, 23% in 2014, 40% in 2019, and 10% in 2023. The findings highlight a critical trade-off between peak runoff and NbS implementation: while NbS effectively reduce flood impacts, they also enhance volumetric efficiency by approximately 43%. In high-density areas of the QCMA, flood depth reductions of around 20% suggest that NbS are a viable solution for dense urban environments with limited space. This shows the potential for integrating NbS into existing infrastructure, offering a promising approach for cities facing increasing flooding risks. The proposed methodology provides a practical framework for incorporating NbS into urban stormwater management, addressing gaps in optimizing NbS performance, and offering a pathway to scale their application in other urban areas with various environmental and social contexts.
CMIP6↗
Engineering Antifreeze Proteins to Optimally Resist Engulfment by Ice
Antifreeze proteins (AFPs) facilitate the survival of organisms in cold climates by inhibiting the growth and/or recrystallization of ice. To function, AFPs must first bind to ice crystals; bound AFPs must then resist engulfment by using their nonbinding side (NBS) to pin the ice–water interface. Here, we seek to understand how the molecular characteristics of an NBS, such as its ice-phobicity or shape, influence its ability to resist engulfment. By characterizing the free energy barriers that impede the engulfment of model AFPs, we find that the critical supercooling ΔT*, above which an AFP is engulfed, is dictated by an optimal pinning site on the NBS. We further find that the optimal pinning site is determined by an interplay between the contact line perimeter P and a pinning efficiency η, with ΔT* ∝ ηP at the optimal pinning site. For a hemispherical AFP, which displays progressively inward tapering, we find that η increases during engulfment, whereas P decreases; conversely, an NBS with outward tapering can achieve high P, but it suffers from low η. Because the product of η and P determines ΔT*, the inverse correlation between them limits ΔT. To circumvent such limiting behavior, we propose an NBS shape with an outward bulge; by initially tapering outward, a bulged NBS permits higher P, and by subsequently tapering inward, it promotes high η as well. Importantly, we find that ΔT* is enhanced by more than a factor of 2 with an outward bulge of only 1 nm. We also find that the more ice-phobic an NBS is, the more efficiently it pins the ice–water interface, resulting in a higher ΔT. Furthermore, our findings shed light on how the NBS molecular characteristics influence ΔT* and suggest strategies for engineering the NBS to optimally resist engulfment by ice.
Antifreeze↗
Harnessing Nanobodies for Precision Targeting of Proteoforms: Opportunities and Challenges in Therapeutics and Diagnostics
Proteoforms are biologically distinct yet structurally similar proteins that play key roles in driving disease progression but are rarely accounted for in the development of therapeutics and diagnostics. Nanobodies (Nbs) have emerged as a therapeutic and diagnostic “silver bullet” as they possess unique structural and functional attributes that offer advantages over traditional antibodies. One of the most profound advantages of Nbs is the heightened sensitivity and ability to distinguish subtle changes in the conformation of a given protein. Thus, Nbs have significant potential as therapeutic and diagnostic agents that can identify and distinguish specific pathological proteoforms that underlie a given disease. However, there remain significant challenges in obtaining sufficient quantities and purities of specific proteoform antigens that are required for engineering proteoform-specific Nbs. Recent advancements in chemical biology tools for precision proteoform synthesis have made this task feasible for the first time. In this perspective, we discuss the advantages and challenges associated with developing proteoform-specific Nbs and how success in this endeavor will significantly advance the fields of therapeutics and diagnostics.
Antigens↗
Development of high-affinity nanobodies specific for Na V 1.4 and Na V 1.5 voltage-gated sodium channel isoforms
Voltage-gated sodium channels, Na V s, are responsible for the rapid rise of action potentials in excitable tissues. Na V channel mutations have been implicated in several human genetic diseases, such as hypokalemic periodic paralysis, myotonia, and long-QT and Brugada syndromes. Here, we generated high-affinity anti-NaV nanobodies (Nbs), Nb17 and Nb82, that recognize the Na V 1.4 (skeletal muscle) and Na V 1.5 (cardiac muscle) channel isoforms. These Nbs were raised in llama (Lama glama) and selected from a phage display library for high affinity to the C-terminal (CT) region of Na V 1.4. The Nbs were expressed in Escherichia coli, purified, and biophysically characterized. Development of high-affinity Nbs specifically targeting a given human Na V isoform has been challenging because they usually show undesired crossreactivity for different Na V isoforms. Our results show, however, that Nb17 and Nb82 recognize the CTNa V 1.4 or CTNa V 1.5 over other CTNav isoforms. Kinetic experiments by biolayer interferometry determined that Nb17 and Nb82 bind to the CTNa V 1.4 and CTNa V 1.5 with high affinity (K D ~ 40–60 nM). In addition, as proof of concept, we show that Nb82 could detect Na V 1.4 and Na V 1.5 channels in mammalian cells and tissues by Western blot. Furthermore, human embryonic kidney cells expressing holo Na V 1.5 channels demonstrated a robust FRET-binding efficiency for Nb17 and Nb82. Our work lays the foundation for developing Nbs as anti-Na V reagents to capture Na V s from cell lysates and as molecular visualization agents for Na V s.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Visualizing the out-of-plane electronic dispersions in an intercalated transition metal dichalcogenide
Layered transition metal dichalcogenides have a rich phase diagram and they feature two-dimensionality in numerous physical properties. Co 1/3 NbS 2 is one of the newest members of this family where Co atoms are intercalated into the van der Waals gaps between NbS 2 layers. Here, we study the three-dimensional electronic band structure of Co 1/3 NbS 2 using both surface and bulk sensitive angle-resolved photoemission spectroscopy. We show that the electronic bands do not fit into the rigid band shift picture after the Co intercalation. Instead, Co 1/3 NbS 2 displays a different orbital character near the Fermi level compared to the pristine NbS 2 compound and has a clear band dispersion in the k z direction despite its layered structure. Our photoemission study demonstrates the out-of-plane electronic correlations introduced by the Co intercalation, thus offering a different perspective on this compound. Finally, we propose how Fermi level tuning could lead to exotic phases such as spin density wave instability.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Clean 2D superconductivity in a bulk van der Waals superlattice
Alternative route to a 2D superconductor Single layers of transition metal dichalcogenides exhibit exotic properties, including superconductivity. The usual route to obtaining such samples is to exfoliate a three-dimensional (3D) crystal. Devarakonda et al. instead grew a superlattice comprising alternating layers of the transition metal dichalcogenide hexagonal NbS 2 and the material Ba 3 NbS 5 (see the Perspective by Schoop). The inert Ba 3 NbS 5 layers serve to dissociate the superconducting NbS 2 layers from one another, resulting in 2D superconductivity with high carrier mobility. The combination of high mobility and reduced dimensionality may give rise to exotic quantum phases. Science , this issue p. 231 see also p. 170
Science & Technology - Other Topics↗
Power System Recovery Coordinated with (Non-)Black-Start Generators
Power restoration is an urgent task after a black-out, and recovery efficiency is critical when quantifying system resilience. Multiple elements should be considered to restore the power system quickly and safely. This paper proposes a recovery model to solve a direct-current optimal power flow (DCOPF) based on mixed-integer linear programming (MILP). Since most of the generators cannot start independently, the interaction between black-start (BS) and non-black-start (NBS) generators must be modeled appropriately. The energization status of the NBS is coordinated with the recovery status of transmission lines, and both of them are modeled as binary variables. Also, only after an NBS unit receives the cranking power through connected transmission lines, will it be allowed to participate in the following system dispatch. The amount of cranking power is estimated as a fixed proportion to the maximum generation capacity. The proposed model is validated on several test systems, as well as a 1393-bus representation system of the Puerto Rican electric power grid. Test results demonstrate how the recovery of NBS units and damaged transmission lines can be optimized, resulting in an efficient and well-coordinated recovery procedure.
Zhao, Meng↗
Spontaneous self-intercalation of copper atoms into transition metal dichalcogenides
Intercalated transition metal dichalcogenides (TMDs) have attracted substantial interest due to their exciting electronic properties. Here, we report a unique approach where copper (Cu) atoms from bulk Cu solid intercalate spontaneously into van der Waals (vdW) gaps of group IV and V layered TMDs at room temperature and atmospheric pressure. This distinctive phenomenon is used to develop a strategy to synthesize Cu species–intercalated layered TMD compounds. A series of Cu-intercalated 2H-NbS 2 compounds were obtained with homogeneous distribution of Cu intercalates in the form of monovalent Cu (I), occupying the tetrahedral sites coordinated by S atoms within the interlayer space of NbS 2 . The Fermi level of NbS 2 shifts up because of the intercalation of Cu, resulting in the improvement of electrical conductivity in the z-direction. On the other hand, intercalation of Cu into vdW gaps of NbS 2 systematically suppresses the superconducting transition temperature (T c ) and superconducting volume fraction.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Layered Nano-Mosaic of Niobium Disulfide Heterostructures by Direct Sulfidation of Niobium Carbide MXenes for Hydrogen Evolution
MXene-transition metal dichalcogenide (TMD) heterostructures are synthesized through a one-step heat treatment of Nb 2 C and Nb 4 C 3 . These MXenes are used without delamination or any pre-treatment. Heat treatments accomplish the sacrificial transformation of these MXenes into TMD (NbS 2 ) at 700 and 900 °C under H 2 S. This work investigates, for the first time, the role of starting MXene phase in the derivative morphology. It is shown that while treatment of Nb 2 C at 700 °C leads to the formation of pillar-like structures on the parent MXene, Nb 4 C 3 produces nano-mosaic layered NbS 2 . At 900 °C, both MXene phases, of the same transition metal, fully convert into nanomosaic layered NbS 2 preserving the parent MXene’s layered morphology. When tested as electrodes for hydrogen evolution reaction, Nb 4 C 3 -derived hybrids show better performance than Nb 2 C derivatives. The Nb 4 C 3 -derived heterostructure exhibits a low overpotential of 198 mV at 10 mA cm -2 and a Tafel slope of 122 mV dec -1 , with good cycling stability in an acidic electrolyte
36 MATERIALS SCIENCE↗
Charge correlations and magnetoelastic coupling in intercalated transition metal dichalcogenides
The large van der Waals gap in transition metal dichalcogenides (TMDs) offers an avenue to tune the ground state of 2D materials through the intercalation of magnetic atoms. Here, we investigate the charge correlations in Fe 1/3 TaS 2 , Co 1/3 TaS 2 , and Fe 0.35 NbS 2 by combining angle-resolved photoemission spectroscopy (ARPES), x-ray scattering, magnetometry, and density functional theory (DFT). We find that, while short-range charge fluctuations develop in Ta-based compounds, Fe 0.35 NbS 2 exhibits long-range charge order which is strongly coupled with magnetic order and tunable by external magnetic field. Our electronic structure analysis reveals that intercalation reconstructs the Fermi surface via charge transfer and band renormalization, yet does not generate the nesting conditions compatible with the observed ordering vectors. Complementary phonon calculations further exclude a conventional electron-phonon origin of charge order. Together, these results establish magnetoelastic coupling as the dominant mechanism behind charge ordering in Fe 0.35 NbS 2 and highlight the contrasting role of Nb and Ta hosts in stabilizing correlated ground states in intercalated TMDs.
36 MATERIALS SCIENCE↗
The RNA-binding protein Modulo promotes neural stem cell maintenance in Drosophila
A small population of stem cells in the developing Drosophila central nervous system generates the large number of different cell types that make up the adult brain. To achieve this, these neural stem cells (neuroblasts, NBs) divide asymmetrically to produce non-identical daughter cells. The balance between stem cell self-renewal and neural differentiation is regulated by various cellular machinery, including transcription factors, chromatin remodelers, and RNA-binding proteins. The list of these components remains incomplete, and the mechanisms regulating their function are not fully understood, however. Here, we identify a role for the RNA-binding protein Modulo (Mod; nucleolin in humans) in NB maintenance. We employ transcriptomic analyses to identify RNA targets of Mod and assess changes in global gene expression following its knockdown, results of which suggest a link with notable proneural genes and those essential for neurogenesis. Mod is expressed in larval brains and its loss leads to a significant decrease in the number of central brain NBs. Stem cells that remain lack expression of key NB identity factors and exhibit cell proliferation defects. Mechanistically, our analysis suggests these deficiencies arise at least in part from altered cell cycle progression, with a proportion of NBs arresting prior to mitosis. Overall, our data show that Mod function is essential for neural stem cell maintenance during neurogenesis.
Parra, Amalia S.↗
Materials Data on Nb11S12 by Materials Project
(Nb)3(NbS3)2(NbS)6 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of six niobium molecules; four NbS sheets oriented in the (0, 0, 1) direction; and two NbS3 sheets oriented in the (0, 0, 1) direction. In each NbS sheet, there are three inequivalent Nb+2.18+ sites. In the first Nb+2.18+ site, Nb+2.18+ is bonded in a distorted T-shaped geometry to three S2- atoms. There are one shorter (2.44 Å) and two longer (2.45 Å) Nb–S bond lengths. In the second Nb+2.18+ site, Nb+2.18+ is bonded in a distorted T-shaped geometry to three S2- atoms. There are two shorter (2.45 Å) and one longer (2.46 Å) Nb–S bond lengths. In the third Nb+2.18+ site, Nb+2.18+ is bonded in a distorted T-shaped geometry to three S2- atoms. There are two shorter (2.44 Å) and one longer (2.45 Å) Nb–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three Nb+2.18+ atoms. In the second S2- site, S2- is bonded in a distorted T-shaped geometry to three Nb+2.18+ atoms. In the third S2- site, S2- is bonded in a distorted T-shaped geometry to three Nb+2.18+ atoms. In each NbS3 sheet, there are two inequivalent Nb+2.18+ sites. In the first Nb+2.18+ site, Nb+2.18+ is bonded to six S2- atoms to form edge-sharing NbS6 octahedra. There are a spread of Nb–S bond distances ranging from 2.42–2.46 Å. In the second Nb+2.18+ site, Nb+2.18+ is bonded to six S2- atoms to form edge-sharing NbS6 octahedra. There are a spread of Nb–S bond distances ranging from 2.42–2.46 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in an L-shaped geometry to two Nb+2.18+ atoms. In the second S2- site, S2- is bonded in a distorted L-shaped geometry to two Nb+2.18+ atoms. In the third S2- site, S2- is bonded in an L-shaped geometry to two Nb+2.18+ atoms. In the fourth S2- site, S2- is bonded in an L-shaped geometry to two Nb+2.18+ atoms. In the fifth S2- site, S2- is bonded in a distorted L-shaped geometry to two Nb+2.18+ atoms. In the sixth S2- site, S2- is bonded in an L-shaped geometry to two Nb+2.18+ atoms.
36 MATERIALS SCIENCE↗
Evaluation of powder metallurgy manufactured nanostructured bainitic steel for wind turbine gearbox applications
This project evaluated the feasibility of nanostructured bainitic steel (NBS) for wind turbine gearbox applications. NBS alloys show superior rolling-contact fatigue and wear performance and require only minimal heat-treatment steps to form the desirable microstructure. However, despite the single-step heat treatment, NBS takes longer to form the target microstructure, and the high carbon content of the alloy requires careful processing to avoid cracking.
17 WIND ENERGY↗
Optimizing Optical Searches for Supermassive Black Hole Binaries in Active Galactic Nuclei Light Curves: Fourier versus Bayesian Periodicity Detection
Simulations predict that supermassive black hole binaries (SMBHBs) will exhibit periodic brightness variations that may exceed the stochastic variability intrinsic to active galactic nuclei (AGN). In this paper, we simulate SMBHBs with damped random walk (DRW) AGN variability and an added sinusoidal signal from the orbital motion, and test three methods—a generalized Lomb–Scargle periodogram (GLSP), a nested Bayesian sampler (NBS), and a weighted wavelet z-transform (or WWZ)—to determine which is best at recovering the periodicity. Our simulated light curves follow the properties of the Catalina Real-Time Transient Survey (or CRTS), Legacy Survey of Space and Time (LSST), and Zwicky Transient Facility (ZTF) to best inform current and future SMBHB searches. We map a broad range of parameter space and identify which DRW-only light curves best mimic periodicity and pass each method’s model selection. The NBS performs best at detecting periodicity and filtering out DRW-only light curves. Combined candidate selection with both the NBS and GLSP significantly reduces false-positive rates (FPRs) with marginal impact on true-positive rates (TPRs). With this joint model selection pipeline, we find the lowest FPRs in ZTF-like simulations and the highest detection rates in LSST-like simulations. Using a modified computation of the false-alarm probability with GLSP, we efficiently triage LSST AGN light curves (∼10 7 light curves in ∼10–30 hr) and achieve TPRs and FPRs of ∼40% and ∼0.5%, respectively.
Banaszak, Sebastian M. [Vanderbilt Univ., Nashvill↗