New Methods for Evaluating Energy Infrastructure Development Risks.

Many energy technologies that can provide reliable, low-carbon electricity generation are confined to nations that have access to robust technical and economic capabilities, either on their own or through geopolitical alliances. Equally important, these nations maintain a degree of institutional capacity that could lower the risks associated with deploying emergent energy technologies such as advanced nuclear or carbon capture and storage. The complexity, expense, and scrutiny that come with building these facilities make them infeasible choices for most nations. This paradigm is slowly changing, as the pressing need for low-carbon electricity generation and ongoing efforts to develop modular nuclear and carbon capture technologies have opened the door for potentially wider markets, including in nations without substantial institutional capacity. Here, using advanced nuclear technologies as our testbed, we develop new methods to evaluate national readiness for deploying complex energy infrastructure. Specifically, we use Data Envelopment Analysis-a method that eliminates the need for expert judgment-to benchmark performance across nations. We find that approximately 80% of new nuclear deployment occurs in nations that are in the top two quartiles of institutional and economic performance. However, 85% of potential low-carbon electricity demand growth is in nations that are in the bottom two quartiles of performance. We offer iconic paradigms for deploying nuclear power in each of these clusters of nations if the goal is to mitigate risk. Our research helps redouble efforts by industry, regulators, and international development agencies to focus on areas where readiness is low and risk correspondingly higher.

AVONET: morphological, ecological and geographical data for all birds.

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride.

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) have garnered increasing attention over the last few years due to their superior optical properties. However, despite the vast range of experimental results and theoretical calculations, the defect structure responsible for the observed emission has remained elusive. Here, by controlling the incorporation of impurities into hBN via various bottom-up synthesis methods and directly through ion implantation, we provide direct evidence that the visible SPEs are carbon related. Room-temperature optically detected magnetic resonance is demonstrated on ensembles of these defects. We perform ion-implantation experiments and confirm that only carbon implantation creates SPEs in the visible spectral range. Computational analysis of the simplest 12 carbon-containing defect species suggest the negatively charged [Formula: see text] defect as a viable candidate and predict that out-of-plane deformations make the defect environmentally sensitive. Our results resolve a long-standing debate about the origin of single emitters at the visible range in hBN and will be key to the deterministic engineering of these defects for quantum photonic devices.

Implications of Large-Effect Loci for Conservation: A Review and Case Study with Pacific Salmon.

The increasing feasibility of assembling large genomic datasets for non-model species presents both opportunities and challenges for applied conservation and management. A popular theme in recent studies is the search for large-effect loci that explain substantial portions of phenotypic variance for a key trait(s). If such loci can be linked to adaptations, 2 important questions arise: 1) Should information from these loci be used to reconfigure conservation units (CUs), even if this conflicts with overall patterns of genetic differentiation? 2) How should this information be used in viability assessments of populations and larger CUs? In this review, we address these questions in the context of recent studies of Chinook salmon and steelhead (anadromous form of rainbow trout) that show strong associations between adult migration timing and specific alleles in one small genomic region. Based on the polygenic paradigm (most traits are controlled by many genes of small effect) and genetic data available at the time showing that early-migrating populations are most closely related to nearby late-migrating populations, adult migration differences in Pacific salmon and steelhead were considered to reflect diversity within CUs rather than separate CUs. Recent data, however, suggest that specific alleles are required for early migration, and that these alleles are lost in populations where conditions do not support early-migrating phenotypes. Contrasting determinations under the US Endangered Species Act and the State of California's equivalent legislation illustrate the complexities of incorporating genomics data into CU configuration decisions. Regardless how CUs are defined, viability assessments should consider that 1) early-migrating phenotypes experience disproportionate risks across large geographic areas, so it becomes important to identify early-migrating populations that can serve as reliable sources for these valuable genetic resources; and 2) genetic architecture, especially the existence of large-effect loci, can affect evolutionary potential and adaptability.

A multifunctional shape-morphing elastomer with liquid metal inclusions.

Natural soft tissue achieves a rich variety of functionality through a hierarchy of molecular, microscale, and mesoscale structures and ordering. Inspired by such architectures, we introduce a soft, multifunctional composite capable of a unique combination of sensing, mechanically robust electronic connectivity, and active shape morphing. The material is composed of a compliant and deformable liquid crystal elastomer (LCE) matrix that can achieve macroscopic shape change through a liquid crystal phase transition. The matrix is dispersed with liquid metal (LM) microparticles that are used to tailor the thermal and electrical conductivity of the LCE without detrimentally altering its mechanical or shape-morphing properties. Demonstrations of this composite for sensing, actuation, circuitry, and soft robot locomotion suggest the potential for versatile, tissue-like multifunctionality.

Interoceptive Sensibility in Professional Dancers Living With or Without Pain: A Cross-Sectional Study.

BACKGROUND: There is a growing body of literature investigating the use of manual therapy to modulate pain through interoceptive pathways, but studies amongst the dancer population are lacking. OBJECTIVES: To investigate self-reported measures of interoceptive sensibility (IAs) in professional dancers living with or without pain, and to explore associations between IAs and confounding variables (e.g., psychopathologies). METHODS: 128 UK-based adult professional dancers, from any dance style, living with or without pain, completed a cross-sectional online survey. Pain status was self-reported and participants were assigned in three study groups for analyses (pain-free n=26, acute n=30, and chronic pain n=72). The Multidimensional Assessment of Interoceptive Awareness, ver. 2 (MAIA-2) was used to measure IAs. An additional questionnaire was used to collect demographic and putative confounding data (i.e., age, sex, BMI, dance style, employment status, level of experience, mindfulness experience, pain history and management such as manual therapy use, eating disorders, depression, and anxiety). RESULTS: No overall significant difference was found in IAs between groups (pain-free-control, acute, and chronic pain). A one-way ANOVA showed significantly lower scores for the MAIA-2 Non-Distracting subscale in dancers living with pain (acute or chronic) compared to the pain-free-control group. Moreover, an association between manual therapy use and some subscales of the MAIA-2 was found in the population. CONCLUSIONS: Results should be interpreted with caution, as major confounding variables (i.e., psychopathologies) could not be excluded from the analysis due to their high prevalence in the sample. Positive associations between adaptive subscales of the MAIA-2 and the use of manual therapy support a need for further research investigating potential clinical applications using interoceptive pathways in the specialised management of pain in dancers.

Accurate prediction of the properties of materials using the CAM-B3LYP density functional.

Density functionals with asymptotic corrections to the long-range potential provide entry-level methods for calculations on molecules that can sustain charge transfer, but similar applications in materials science are rare. We describe an implementation of the CAM-B3LYP range-separated functional within the Vienna Ab-initio Simulation Package (VASP) framework, together with its analytical functional derivatives. Results obtained for eight representative materials: aluminum, diamond, graphene, silicon, NaCl, MgO, 2D h-BN, and 3D h-BN, indicate that CAM-B3LYP predictions embody mean-absolute deviations (MAD) compared to HSE06 that are reduced by a factor of six for lattice parameters, four for quasiparticle band gaps, three for the lowest optical excitation energies, and six for exciton binding energies. Further, CAM-B3LYP appears competitive compared to ab initio G0 W0 and Bethe-Salpeter equation approaches. The CAM-B3LYP implementation in VASP was verified by comparison of optimized geometries and reaction energies for isolated molecules taken from the ACCDB database, evaluated in large periodic unit cells, to analogous results obtained using Gaussian basis sets. Using standard GW pseudopotentials and energy cutoffs for the plane-wave calculations and the aug-cc-pV5Z basis set for the atomic-basis ones, the MAD in energy for 1738 chemical reactions was 0.34 kcal mol-1 , while for 480 unique bond lengths this was 0.0036 Å; these values reduced to 0.28 kcal mol-1 (largest error 0.94 kcal mol-1 ) and 0.0009 Å by increasing the plane-wave cutoff energy to 850 eV.

A mobile sex-determining region, male-specific haplotypes and rearing environment influence age at maturity in Chinook salmon.

Variation in age at maturity is an important contributor to life history and demographic variation within and among species. The optimal age at maturity can vary by sex, and the ability of each sex to evolve towards its fitness optimum depends on the genetic architecture of maturation. Using GWAS of RAD sequencing data, we show that age at maturity in Chinook salmon exhibits sex-specific genetic architecture, with age at maturity in males influenced by large (up to 20 Mb) male-specific haplotypes. These regions showed no such effect in females. We also provide evidence for translocation of the sex-determining gene between two different chromosomes. This has important implications for sexually antagonistic selection, particularly that sex linkage of adaptive genes may differ within and among populations based on chromosomal location of the sex-determining gene. Our findings will facilitate research into the genetic causes of shifting demography in Chinook salmon as well as a better understanding of sex determination in this species and Pacific salmon in general.

US nuclear power: The vanishing low-carbon wedge.

Nuclear power holds the potential to make a significant contribution to decarbonizing the US energy system. Whether it could do so in its current form is a critical question: Existing large light water reactors in the United States are under economic pressure from low natural gas prices, and some have already closed. Moreover, because of their great cost and complexity, it appears most unlikely that any new large plants will be built over the next several decades. While advanced reactor designs are sometimes held up as a potential solution to nuclear power's challenges, our assessment of the advanced fission enterprise suggests that no US design will be commercialized before midcentury. That leaves factory-manufactured, light water small modular reactors (SMRs) as the only option that might be deployed at significant scale in the climate-critical period of the next several decades. We have systematically investigated how a domestic market could develop to support that industry over the next several decades and, in the absence of a dramatic change in the policy environment, have been unable to make a convincing case. Achieving deep decarbonization of the energy system will require a portfolio of every available technology and strategy we can muster. It should be a source of profound concern for all who care about climate change that, for entirely predictable and resolvable reasons, the United States appears set to virtually lose nuclear power, and thus a wedge of reliable and low-carbon energy, over the next few decades.

Single-photon emitters in hexagonal boron nitride: a review of progress.

This report summarizes progress made in understanding properties such as zero-phonon-line energies, emission and absorption polarizations, electron-phonon couplings, strain tuning and hyperfine coupling of single photon emitters in hexagonal boron nitride. The primary aims of this research are to discover the chemical nature of the emitting centres and to facilitate deployment in device applications. Critical analyses of the experimental literature and data interpretation, as well as theoretical approaches used to predict properties, are made. In particular, computational and theoretical limitations and challenges are discussed, with a range of suggestions made to overcome these limitations, striving to achieve realistic predictions concerning the nature of emitting centers. A symbiotic relationship is required in which calculations focus on properties that can easily be measured, whilst experiments deliver results in a form facilitating mass-produced calculations.

Network topologies dictate electromechanical coupling in liquid metal-elastomer composites.

Elastomers embedded with micro- and nanoscale droplets of liquid metal (LM) alloys like eutectic gallium-indium (EGaIn) can exhibit unique combinations of elastic, thermal, and electrical properties that are difficult to achieve using rigid filler. For composites with sufficient concentrations of liquid metal, the LM droplets can form percolating networks that conduct electricity and deform with the surrounding elastomer as the composite is stretched. Surprisingly, experimental measurements performed on LM-embedded elastomers (LMEEs) show that the total electrical resistance of the composite increases only slightly even as the elastomer is stretched to several times its natural length. In contrast, Pouillet's law would predict an exponential increase in resistance (Ω) with stretch (λ) due to the incompressibility of liquid metal and elastomer. In this manuscript, we perform a computational analysis to examine the unique electromechanical properties of conductive LMEE composites. Our analysis suggests that the gauge factor that quantifies electromechanical coupling (i.e. G = {ΔΩ/Ω0}/λ) decreases with increasing tortuosity of the conductive pathways formed by the connected LM droplets. A dimensionless parameter for path tortuosity can be used to estimate G for statistically homogeneous LMEE composites. These results rationalize experimental observations and provide insight into the influence of liquid metal droplet assembly on the functionality of the composite.

Size of liquid metal particles influences actuation properties of a liquid crystal elastomer composite.

Composites of liquid crystal elastomer (LCE) that are electrically conductive have the potential to function as soft "artificial muscle" actuators that can be reversibly stimulated with electrical Joule-heating. Conductivity can be achieved by embedding the LCE with droplets of an alloy of gallium and indium that is liquid at room temperature. These soft artificial muscles are capable of >50% reversible actuation with an applied load. The key to actuation at high loadings of liquid metal (LM) is that the droplets deform with the surrounding matrix. By controlling the size of LM droplets through simple processing techniques, we show that the actuator properties of the LM-LCE muscle can be tuned. For example, composites with smaller liquid metal particles (ca. 10 µm or less) are stiffer than those with larger liquid metal particles (ca. >100 µm) and are capable of greater force output. However, smaller particles reduce actuation strain and composites with large particles exhibit significantly greater stroke length. Such tunability in actuation properties permits the fabrication of specialized soft artificial muscles, where processing of the composite controls actuation strain and actuation force.

Assessment of biosimilarity under native and heat-stressed conditions: rituximab, bevacizumab, and trastuzumab originators and biosimilars.

Biosimilars are highly similar to, but not identical with, their originator products. As a result, structural differences between originators and biosimilars can be difficult to detect and characterize without the appropriate analytical tools. Therefore, we first focus on identifying initial structural differences between rituximab, bevacizumab, and trastuzumab originator and biosimilar pairs and later address how these differences change after applying thermal stress at 40 °C with orbital shaking for 4 weeks. Prior to incubation, we detected comparable secondary and tertiary structures for each pair and identified different levels of soluble aggregates, charge variants, and molecular weight variants due to differences in glycoforms and the number of C-terminal lysine groups. Over the course of incubation, we compared differences in charge variants and unfolding patterns. Taken together, our study provides a comparability exercise, providing information on the minor differences present between originator and biosimilar products and how those differences are impacted by stress.

Structure, stability and water adsorption on ultra-thin TiO2 supported on TiN.

Interfacial metal-oxide systems with ultra-thin oxide layers are of high interest for their use in catalysis. The chemical activity of ultra-thin metal-oxide layers can be substantially enhanced compared to interfacial models with thicker oxide. In this study, we present a Density Functional Theory (DFT) investigation of the structure of ultra-thin rutile layers (one and two TiO2 layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti-O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti3+ cations in TiO2. The concentration of Ti3+ is proportionally higher in the ultra-thin oxide, compared to interfacial models with thicker oxide layers. The structure of the one-layer oxide slab is strongly distorted at the interface while the thicker TiO2 layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly defective interfaces. Isolated water molecules dissociate when adsorbed at the TiO2 layers. At higher coverages, the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. This behaviour is similar to that observed on thicker oxide in TiO2-TiN interfaces or pure TiO2 surfaces. In contrast, interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. The high concentration on reduced Ti3+ introduces significant distortions in the O-defective slab. Whereas, a water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO1.75-TiN interface, where the Ti3+ states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO2-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultra-thin TiO2 with potential application as photocatalytic water splitting devices.

Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form.

The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)-thiyl, with Au(I)-thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)-thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s-d hybridization and charge polarization effects that perturbatively mix in some Au(I)-thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)-thiolate involvement. Predictions that Brust-Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)-thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established.

Superconductivity in intercalated buckled two-dimensional materials: KGe2.

Germanene has emerged as a novel two-dimensional material with various interesting properties and applications. Here we report the possibility of superconductivity in a stable potassium intercalated germanene compound, KGe2, with a transition temperature Tc ∼ 11 K, and an electron-phonon coupling of 1.9. Applying a 5% tensile strain, which reduces the buckling height by 4.5%, leads to the reduction of the electron-phonon coupling by 11% and a slight increase in Tc ∼ 12 K. That is, strong electron-phonon coupling results from the buckled structure of the germanene layers. Despite being an intercalated van der Waals material similar to intercalated graphite superconductors, it does not possess an occupied interlayer state.

Magnetic properties of stoichiometric and defective Co9S8.

In this paper, we present a detailed study of the stoichiometric and reduced Co9S8 pentlandite magnetic properties, based on density functional theory. We analyze both its geometry and electronic properties and show that only by the inclusion of the Hubbard term it is possible to correctly describe d-d splitting, which is necessary to accurately characterize the Co9S8 spin configuration and its antiferromagnetic nature. We also analyze the effect of sulfur vacancies and predict the formation of ferromagnetic clusters that give local ferromagnetic character to non-stoichiometric Co9S8, which may explain the contradictory experimental results reported in the literature.

A priori calculations of the free energy of formation from solution of polymorphic self-assembled monolayers.

Modern quantum chemical electronic structure methods typically applied to localized chemical bonding are developed to predict atomic structures and free energies for meso-tetraalkylporphyrin self-assembled monolayer (SAM) polymorph formation from organic solution on highly ordered pyrolytic graphite surfaces. Large polymorph-dependent dispersion-induced substrate-molecule interactions (e.g., -100 kcal mol(-1) to -150 kcal mol(-1) for tetratrisdecylporphyrin) are found to drive SAM formation, opposed nearly completely by large polymorph-dependent dispersion-induced solvent interactions (70-110 kcal mol(-1)) and entropy effects (25-40 kcal mol(-1) at 298 K) favoring dissolution. Dielectric continuum models of the solvent are used, facilitating consideration of many possible SAM polymorphs, along with quantum mechanical/molecular mechanical and dispersion-corrected density functional theory calculations. These predict and interpret newly measured and existing high-resolution scanning tunnelling microscopy images of SAM structure, rationalizing polymorph formation conditions. A wide range of molecular condensed matter properties at room temperature now appear suitable for prediction and analysis using electronic structure calculations.

Utilizing the GentleWave® System for Debridement of Undetected Apical Anatomy.

AIM AND BACKGROUND: Debriding and disinfecting complex anatomies within the root canal system pose a major challenge during root canal therapy. Even with current chemomechanical techniques, debris and bacterial remnants are commonly left behind, which are generally believed to increase the risk of endodontic failure. This case details the use of a new technique to debride complex apical anatomy in a maxillary molar. CASE REPORT: A 48-year-old female presented to the clinic with a chief complaint of increasing pain in her tooth. Clinical examination of the right first maxillary molar (#3) revealed moderate sensitivity to percussion and mild sensitivity to palpation. A pulpal diagnosis of symptomatic irreversible pulpitis and a periapi-cal diagnosis of symptomatic apical periodontitis were made. Mechanical instrumentation was performed using rotary file size #25/.04 for the mesiobuccal and distobuccal canals and size #25/.06 for the palatal canal to create a fluid path and enable obturation of the root canal system following the GentleWave® Procedure. The GentleWave Procedure was completed using Multisonic Ultracleaning™ for complete debridement and disinfection of the root canal system. The tooth was obturated using a warm vertical continuous wave obturation technique. Postoperative radiographs revealed complex anatomy within the apical third that was undetected both during pre-operative radiography and mechanical instrumentation. The palatal canal exhibited a complex apical delta with multiple points of exit, and the mesiobuccal canal revealed an undetected lateral canal within the apical third that had a separate and distinct egress. Conclusion and clinical significance: It is important for the clinician to debride and disinfect complex anatomy within the root canal system to reduce the risk of endodontic failure. This case report highlights the clinical significance of utilizing the GentleWave Procedure for detecting complex apical anatomy during endodontic therapy.

Electrocatalytic Activity of a 2D Phosphorene-Based Heteroelectrocatalyst for Photoelectrochemical Cells.

Research into efficient synthesis, fundamental properties, and potential applications of phosphorene is currently the subject of intense investigation. Herein, solution-processed phosphorene or few-layer black phosphorus (FL-BP) sheets are prepared using a microwave exfoliation method and used in photoelectrochemical cells. Based on experimental and theoretical (DFT) studies, the FL-BP sheets are found to act as catalytically active sites and show excellent electrocatalytic activity for triiodide reduction in dye-sensitized solar cells. Importantly, the device fabricated based on the newly designed cobalt sulfide (CoSx ) decorated nitrogen and sulfur co-doped carbon nanotube heteroelectrocatalyst coated with FL-BP (FL-BP@N,S-doped CNTs-CoSx ) displayed an impressive photovoltaic efficiency of 8.31 %, outperforming expensive platinum based cells. This work paves the way for using phosphorene-based electrocatalysts for next-generation energy-storage systems.