Tunable Chemical Disorder in Concentrated Alloys: Defect Physics and Radiation Performance.

The development of advanced structural alloys with performance meeting the requirements of extreme environments in nuclear reactors has been long pursued. In the long history of alloy development, the search for metallic alloys with improved radiation tolerance or increased structural strength has relied on either incorporating alloying elements at low concentrations to synthesize so-called dilute alloys or incorporating nanoscale features to mitigate defects. In contrast to traditional approaches, recent success in synthesizing multicomponent concentrated solid-solution alloys (CSAs), including medium-entropy and high-entropy alloys, has vastly expanded the compositional space for new alloy discovery. Their wide variety of elemental diversity enables tunable chemical disorder and sets CSAs apart from traditional dilute alloys. The tunable electronic structure critically lowers the effectiveness of energy dissipation via the electronic subsystem. The tunable chemical complexity also modifies the scattering mechanisms in the atomic subsystem that control energy transport through phonons. The level of chemical disorder depends substantively on the specific alloying elements, rather than the number of alloying elements, as the disorder does not monotonically increase with a higher number of alloying elements. To go beyond our knowledge based on conventional alloys and take advantage of property enhancement by tuning chemical disorder, this review highlights synergistic effects involving valence electrons and atomic-level and nanoscale inhomogeneity in CSAs composed of multiple transition metals. Understanding of the energy dissipation pathways, deformation tolerance, and structural stability of CSAs can proceed by exploiting the equilibrium and non-equilibrium defect processes at the electronic and atomic levels, with or without microstructural inhomogeneities at multiple length scales. Knowledge of tunable chemical disorder in CSAs may advance the understanding of the substantial modifications in element-specific alloy properties that effectively mitigate radiation damage and control a material's response in extreme environments, as well as overcome strength-ductility trade-offs and provide overarching design strategies for structural alloys.

Removal of dermal piercings.

We report a case of a patient with dermal piercings of the hand that were used to anchor body jewelry. The piercings had become infected and were causing the patient pain. She requested that they be removed in the emergency department (ED). Both piercings were successfully removed by anesthetizing the area and creating a small linear incision at the base of the stud before gentle removal of the dermal anchor with a hemostat. This report outlines a simple way to remove the piercings while minimizing tissue damage.

Sexual selection drives the coevolution of male and female reproductive traits in Peromyscus mice.

When females mate with multiple partners within a single reproductive cycle, sperm from rival males may compete for fertilization of a limited number of ova, and females may bias the fertilization of their ova by particular sperm. Over evolutionary timescales, these two forms of selection shape both male and female reproductive physiology when females mate multiply, yet in monogamous systems, post-copulatory sexual selection is weak or absent. Here, we examine how divergent mating strategies within a genus of closely related mice, Peromyscus, have shaped the evolution of reproductive traits. We show that in promiscuous species, males exhibit traits associated with increased sperm production and sperm swimming performance, and females exhibit traits that are predicted to limit sperm access to their ova including increased oviduct length and a larger cumulus cell mass surrounding the ova, compared to monogamous species. Importantly, we found that across species, oviduct length and cumulus cell density are significantly correlated with sperm velocity, but not sperm count or relative testes size, suggesting that these female traits may have coevolved with increased sperm quality rather than quantity. Taken together, our results highlight how male and female traits evolve in concert and respond to changes in the level of post-copulatory sexual selection.

Intracranial Intraosseous Catheter Placement to Temporize an Epidural Hematoma.

Acute epidural hematomas can lead to rapid neurologic decompensation and death. Epidural hematomas may require emergency surgical clot removal, but many patients live far away from a trauma center. This case report describes a pediatric patient with an acute epidural hematoma with significant neurologic compromise who initially presented to a nontrauma center. The emergency department (ED) had no neurosurgeon or equipment to perform burr hole craniostomy. The emergency physician at the nontrauma ED inserted an intraosseous catheter intracranially to temporarily decompress the hematoma due to long transport times. The patient survived with complete neurologic recovery. This is the youngest known patient in whom an intraosseous catheter was used to drain an intracranial hematoma.

Principles of Screening for Disease and Health Risk Factors in the Emergency Department.

The emergency department serves as a critical access point to the health system for many patients, especially those with limited resources. Screening for disease or risk factors for poor health outcomes can potentially improve both individual and population health. Screening initiatives should focus on evidence-based strategies and take local epidemiology and ED capacity into consideration. Initiatives should strive for community support and transparency with patients. They should also be financially sustainable for those involved. Screening can identify patients who can then be counseled, provided with prophylaxis or treatment, or referred to external resources. Through screening and intervention, the ED can serve as a vital contributor to individual and population health.

Reconstructing Nonparametric Productivity Networks.

Network models provide a general representation of inter-connected system dynamics. This ability to connect systems has led to a proliferation of network models for economic productivity analysis, primarily estimated non-parametrically using Data Envelopment Analysis (DEA). While network DEA models can be used to measure system performance, they lack a statistical framework for inference, due in part to the complex structure of network processes. We fill this gap by developing a general framework to infer the network structure in a Bayesian sense, in order to better understand the underlying relationships driving system performance. Our approach draws on recent advances in information science, machine learning and statistical inference from the physics of complex systems to estimate unobserved network linkages. To illustrate, we apply our framework to analyze the production of knowledge, via own and cross-disciplinary research, for a world-country panel of bibliometric data. We find significant interactions between related disciplinary research output, both in terms of quantity and quality. In the context of research productivity, our results on cross-disciplinary linkages could be used to better target research funding across disciplines and institutions. More generally, our framework for inferring the underlying network production technology could be applied to both public and private settings which entail spillovers, including intra- and inter-firm managerial decisions and public agency coordination. This framework also provides a systematic approach to model selection when the underlying network structure is unknown.

Thermal stability and irradiation response of nanocrystalline CoCrCuFeNi high-entropy alloy.

Grain growth and phase stability of a nanocrystalline face-centered cubic (fcc) Ni0.2Fe0.2Co0.2Cr0.2Cu0.2 high-entropy alloy (HEA), either thermally- or irradiation-induced, are investigated through in situ and post-irradiation transmission electron microscopy (TEM) characterization. Synchrotron and lab x-ray diffraction measurements are carried out to determine the microstructural evolution and phase stability with improved statistics. Under in situ TEM observation, the fcc structure is stable at 300 °C with a small amount of grain growth from 15.8 to ∼20 nm being observed after 1800 s. At 500 °C, however, some abnormal growth activities are observed after 1400 s, and secondary phases are formed. Under 3 MeV Ni room temperature ion irradiation up to an extreme dose of nearly 600 displacements per atom, the fcc phase is stable and the average grain size increases from 15.6 to 25.2 nm. Grain growth mechanisms driven by grain rotation, grain boundary curvature, and disorder are discussed.

Craniofacial Injuries Seen With the Introduction of Bicycle-Share Electric Scooters in an Urban Setting.

PURPOSE: Standing electric scooters (e-scooters) are rapidly becoming popular modes of transportation in many urban areas across the United States. However, this increase in popularity has resulted in an increase in traumatic injuries associated with these modes of expedient travel. The purpose of the present study was to determine the types of craniofacial trauma directly related to e-scooter use in a major urban center (Dallas, TX). MATERIALS AND METHODS: We performed a retrospective case series and examined the medical records of the patients who had presented to the emergency department (ED) for trauma related to e-scooter use. Descriptive statistics were calculated for all variables on patient presentation, including incident notes and patient interviews, demographic information, diagnostic tests, trauma (ie, location, type, severity), treatment (ie, type, admission, outpatient referral, follow-up data), and contributing factors (ie, reported or detected alcohol use, use of protective equipment). RESULTS: A total of 90 patients (56 males, 34 females; mean age, 31.8 years) had presented with scooter-related trauma to the ED during the first 7 months of scooters after their introduction to the metropolitan area. A total of 52 admissions (58% of all admissions) involved injuries of the head and face. The patients had presented with a myriad of craniofacial trauma, ranging from abrasions, lacerations, and concussions to intracranial hemorrhage and Le Fort II and III fractures. Of the 52 craniofacial injuries, 30 (58%) were considered severe (ie, fracture, internal hemorrhage, concussion, loss of consciousness), and 22 (42%) were considered minor (ie, lacerations, contusion, abrasion, dental). Alcohol use had been involved in 18% of all scooter-related trauma admissions, and no rider had reported wearing a helmet. CONCLUSIONS: Injuries to the head and face were commonly found with e-scooter admissions in this sample, and the high prevalence of extremity injuries suggested that patients were breaking their fall during the crash. Craniofacial trauma related to e-scooter use could be significantly reduced by the wearing of a protective helmet.

Lattice Distortion and Phase Stability of Pd-Doped NiCoFeCr Solid-Solution Alloys.

In the present study, we have revealed that (NiCoFeCr)100-xPdx (x= 1, 3, 5, 20 atom%) high-entropy alloys (HEAs) have both local- and long-range lattice distortions by utilizing X-ray total scattering, X-ray diffraction, and extended X-ray absorption fine structure methods. The local lattice distortion determined by the lattice constant difference between the local and average structures was found to be proportional to the Pd content. A small amount of Pd-doping (1 atom%) yields long-range lattice distortion, which is demonstrated by a larger (200) lattice plane spacing than the expected value from an average structure, however, the degree of long-range lattice distortion is not sensitive to the Pd concentration. The structural stability of these distorted HEAs under high-pressure was also examined. The experimental results indicate that doping with a small amount of Pd significantly enhances the stability of the fcc phase by increasing the fcc-to-hcp transformation pressure from ~13.0 GPa in NiCoFeCr to 20-26 GPa in the Pd-doped HEAs and NiCoFeCrPd maintains its fcc lattice up to 74 GPa, the maximum pressure that the current experiments have reached.

A novel SOD1-ALS mutation separates central and peripheral effects of mutant SOD1 toxicity.

Transgenic mouse models expressing mutant superoxide dismutase 1 (SOD1) have been critical in furthering our understanding of amyotrophic lateral sclerosis (ALS). However, such models generally overexpress the mutant protein, which may give rise to phenotypes not directly relevant to the disorder. Here, we have analysed a novel mouse model that has a point mutation in the endogenous mouse Sod1 gene; this mutation is identical to a pathological change in human familial ALS (fALS) which results in a D83G change in SOD1 protein. Homozgous Sod1(D83G/D83G) mice develop progressive degeneration of lower (LMN) and upper motor neurons, likely due to the same unknown toxic gain of function as occurs in human fALS cases, but intriguingly LMN cell death appears to stop in early adulthood and the mice do not become paralyzed. The D83 residue coordinates zinc binding, and the D83G mutation results in loss of dismutase activity and SOD1 protein instability. As a result, Sod1(D83G/D83G) mice also phenocopy the distal axonopathy and hepatocellular carcinoma found in Sod1 null mice (Sod1(-/-)). These unique mice allow us to further our understanding of ALS by separating the central motor neuron body degeneration and the peripheral effects from a fALS mutation expressed at endogenous levels.

Strain effects on oxygen vacancy energetics in KTaO3.

Due to lattice mismatch between epitaxial films and substrates, in-plane strain fields are produced in the thin films, with accompanying structural distortions, and ion implantation can be used to controllably engineer the strain throughout the film. Because of the strain profile, local defect energetics are changed. In this study, the effects of in-plane strain fields on the formation and migration of oxygen vacancies in KTaO3 are investigated using first-principles calculations. In particular, the doubly positive charged oxygen vacancy (V) is studied, which is considered to be the main charge state of the oxygen vacancy in KTaO3. We find that the formation energies for oxygen vacancies are sensitive to in-plane strain and oxygen position. The local atomic configuration is identified, and strong relaxation of local defect structure is mainly responsible for the formation characteristics of these oxygen vacancies. Based on the computational results, formation-dependent site preferences for oxygen vacancies are expected to occur under epitaxial strain, which can result in orders of magnitude differences in equilibrium vacancy concentrations on different oxygen sites. In addition, all possible migration pathways, including intra- and inter-plane diffusions, are considered. In contrast to the strain-enhanced intra-plane diffusion, the diffusion in the direction normal to the strained plane is impeded under the epitaxial strain field. These anisotropic diffusion processes can further enhance site preferences.

Predictive modeling of synergistic effects in nanoscale ion track formation.

Molecular dynamics techniques in combination with the inelastic thermal spike model are used to study the coupled effects of the inelastic energy loss due to 21 MeV Ni ion irradiation with pre-existing defects in SrTiO3. We determine the dependence on pre-existing defect concentration of nanoscale track formation occurring from the synergy between the inelastic energy loss and the pre-existing atomic defects. We show that the size of nanoscale ion tracks can be controlled by the concentration of pre-existing disorder. This work identifies a major gap in fundamental understanding on the role of defects in electronic energy dissipation and electron-lattice coupling.

Self-reported health outcomes associated with green-renovated public housing among primarily elderly residents.

OBJECTIVES: Assess the benefits of green renovation on self-reported health of primarily elderly residents of a low-income public housing apartment building. DESIGN AND SETTING: Using questions from the Medicare Health Outcomes Survey, we interviewed residents at baseline and 1 year after green renovation of their 101-unit building in Mankato, Minnesota, comparing self-reported mental and physical health outcomes of 2 sets of residents (all-ages: median, 66 years, n = 40; elder: median, 72 years, n = 22) with outcomes for 2 same-aged low-income Minnesota comparison groups taken from Medicare Health Outcomes Survey participants (n = 40 and 572, respectively). STUDY GROUP: Mankato apartment building residents. INTERVENTIONS: Green renovation including building envelope restoration; new heating, electrical, and ventilation systems; air sealing; new insulation and exterior cladding; window replacement; Energy-Star fixtures and appliances; asbestos and mold abatement; apartment gut retrofits; low volatile organic chemical and moisture-resistant materials; exercise enhancements; and indoor no-smoking policy. MAIN OUTCOME MEASURES: Self-reported health status including Activities of Daily Living and Veteran's Rand 12 (VR-12) survey results; housing condition visual assessment; indoor environmental sampling; and building performance testing. RESULTS: The all-ages study group's mental health improved significantly more than the comparison group's mental health on the basis of mean number of good mental health days in the past month (P = .026) and mean VR-12 mental component score (P = .023). Sixteen percent fewer all-ages study group people versus 8% more comparison group people reported falls (P = .055). The elder study group's 9% improvement in general physical health was not statistically significantly better than the elder comparison group's decline (6%) (P = 0.094). Significantly fewer people in the all-ages group reported smoke in their apartments because of tobacco products (20% vs 0%, P = .005), likely reflecting the new no-smoking policy. CONCLUSIONS: Green healthy housing renovation may result in improved mental and general physical health, prevented falls, and reduced exposure to tobacco smoke.

Composition dependent intrinsic defect structures in SrTiO3.

Intrinsic point defect complexes in SrTiO3 under different chemical conditions are studied using density functional theory. The Schottky defect complex consisting of nominally charged Sr, Ti and O vacancies is predicted to be the most stable defect structure in stoichiometric SrTiO3, with a relatively low formation energy of 1.64 eV per defect. In addition, the mechanisms of defect complex formation in nonstoichiometric SrTiO3 are investigated. Excess SrO leads to the formation of oxygen vacancies and a strontium-titanium antisite defect, while a strontium vacancy together with an oxygen vacancy and a titanium-strontium antisite defect are produced in an excess TiO2 environment. Since point defects, such as oxygen vacancies and cation antisite defects, are intimately related to the functionality of SrTiO3, these results provide guidelines for controlling the formation of intrinsic point defects and optimizing the functionality of SrTiO3 by controlling nonstoichiometric chemical compositions of SrO and TiO2 in experiments.

The effect of electronic energy loss on irradiation-induced grain growth in nanocrystalline oxides.

Grain growth of nanocrystalline materials is generally thermally activated, but can also be driven by irradiation at much lower temperature. In nanocrystalline ceria and zirconia, energetic ions deposit their energy to both atomic nuclei and electrons. Our experimental results have shown that irradiation-induced grain growth is dependent on the total energy deposited, where electronic energy loss and elastic collisions between atomic nuclei both contribute to the production of disorder and grain growth. Our atomistic simulations reveal that a high density of disorder near grain boundaries leads to locally rapid grain movement. The additive effect from both electronic excitation and atomic collision cascades on grain growth demonstrated in this work opens up new possibilities for controlling grain sizes to improve functionality of nanocrystalline materials.

Nanoscale core-shell structure and recrystallization of swift heavy ion tracks in SrTiO3.

It is widely accepted that the interaction of swift heavy ions with many complex oxides is predominantly governed by the electronic energy loss that gives rise to nanoscale amorphous ion tracks along the penetration direction. The question of how electronic excitation and electron-phonon coupling affect the atomic system through defect production, recrystallization, and strain effects has not yet been fully clarified. To advance the knowledge of the atomic structure of ion tracks, we irradiated single crystalline SrTiO3 with 629 MeV Xe ions and performed comprehensive electron microscopy investigations complemented by molecular dynamics simulations. This study shows discontinuous ion-track formation along the ion penetration path, comprising an amorphous core and a surrounding few monolayer thick shell of strained/defective crystalline SrTiO3. Using machine-learning-aided analysis of atomic-scale images, we demonstrate the presence of 4-8% strain in the disordered region interfacing with the amorphous core in the initially formed ion tracks. Under constant exposure of the electron beam during imaging, the amorphous part of the ion tracks readily recrystallizes radially inwards from the crystalline-amorphous interface under the constant electron-beam irradiation during the imaging. Cation strain in the amorphous region is observed to be significantly recovered, while the oxygen sublattice remains strained even under the electron irradiation due to the present oxygen vacancies. The molecular dynamics simulations support this observation and suggest that local transient heating and annealing facilitate recrystallization process of the amorphous phase and drive Sr and Ti sublattices to rearrange. In contrast, the annealing of O atoms is difficult, thus leaving a remnant of oxygen vacancies and strain even after recrystallization. This work provides insights for creating and transforming novel interfaces and nanostructures for future functional applications.

Best practice guidelines for evaluating patients in custody in the emergency department.

Patients in custody due to arrest or incarceration are a vulnerable population that present a unique ethical and logistical challenge for emergency physicians (EPs). People incarcerated in the United States have a constitutional right to health care. When caring for these patients, EPs must balance their ethical obligations to the patient with security and safety concerns. They should refer to their institutional policy for guidance and their local, state, and federal laws, when applicable. Hospital legal counsel and risk management also can be helpful resources. EPs should communicate early and openly with law enforcement personnel to ensure security and emergency department staff safety is maintained while meeting the patient's medical needs. Physicians should consider the least restrictive restraints necessary to ensure security while allowing for medical evaluation and treatment. They should also protect patient privacy as much as possible within departmental constraints, promote the patient's autonomous medical decision-making, and be mindful of ways that medical information could interact with the legal system.

The Cby3/ciBAR1 complex positions the annulus along the sperm flagellum during spermiogenesis.

Proper compartmentalization of the sperm flagellum is essential for fertility. The annulus is a septin-based ring that demarcates the midpiece (MP) and the principal piece (PP). It is assembled at the flagellar base, migrates caudally, and halts upon arriving at the PP. However, the mechanisms governing annulus positioning remain unknown. We report that a Chibby3 (Cby3)/Cby1-interacting BAR domain-containing 1 (ciBAR1) complex is required for this process. Ablation of either gene in mice results in male fertility defects, caused by kinked sperm flagella with the annulus mispositioned in the PP. Cby3 and ciBAR1 interact and colocalize to the annulus near the curved membrane invagination at the flagellar pocket. In the absence of Cby3, periannular membranes appear to be deformed, allowing the annulus to migrate over the fibrous sheath into the PP. Collectively, our results suggest that the Cby3/ciBAR1 complex regulates local membrane properties to position the annulus at the MP/PP junction.