A Radical Pathway and Stabilized Li Anode Enabled by Halide Quaternary Ammonium Electrolyte Additives for Lithium-Sulfur Batteries.

Passivation of the sulfur cathode by insulating lithium sulfide restricts the reversibility and sulfur utilization of Li-S batteries. 3D nucleation of Li2 S enabled by radical conversion may significantly boost the redox kinetics. Electrolytes with high donor number (DN) solvents allow for tri-sulfur (S3 ⋅- ) radicals as intermediates, however, the catastrophic reactivity of such solvents with Li anodes pose a great challenge for their practical application. Here, we propose the use of quaternary ammonium salts as electrolyte additives, which can preserve the partial high-DN characteristics that trigger the S3 ⋅- radical pathway, and inhibit the growth of Li dendrites. Li-S batteries with tetrapropylammonium bromide (T3Br) electrolyte additive deliver the outstanding cycling stability (700 cycles at 1 C with a low-capacity decay rate of 0.049 % per cycle), and high capacity under a lean electrolyte of 5 µLelectrolyte mgsulfur -1 . This work opens a new avenue for the development of electrolyte additives for Li-S batteries.

An Adaptive Multispectral Mechano-Optical System for Multipurpose Applications.

Mechano-optical systems with on-demand adaptability and a broad spectrum from the visible to microwave are critical for complex multiband electromagnetic (EM) applications. Most existing material systems merely have dynamic optical or microwave tunability because their EM wave response is strongly wavelength-dependent. Inspired by cephalopod skin, we develop an adaptive multispectral mechano-optical system based on bilayer acrylic dielectric elastomer (ADE)/silver nanowire (AgNW) films, which reconfigures the surface morphology between wrinkles and cracks via mechanical contraction and stretching. Such morphological evolution regulates the direct transmission/reflection and scattering behavior of visible-infrared light and simultaneously alters the conductive network in a AgNW film to influence its microwave characteristics. The designed system features switching between visible-infrared-microwave transparency and opacity, continuous regulation, wide spectral window (0.38-15.5 µm and 24,200-36,600 µm), excellent recyclability (500 times), and rapid response time (<1 s). These grant the system great potential as platforms for various promising applications such as smart windows, switchable EM devices, dynamic thermal management, adaptive visual stealth, and human motion detection.

Multi-Domain versus Single-Domain: A Magnetic Field is Not a Must for Promoting Spin-Polarized Water Oxidation.

The reaction kinetics of spin-polarized oxygen evolution reaction (OER) can be enhanced by ferromagnetic (FM) catalysts under an external magnetic field. However, applying a magnetic field necessitates additional energy consumption and creates design difficulties for OER. Herein, we demonstrate that a single-domain FM catalyst without external magnetic fields exhibits a similar OER increment to its magnetized multi-domain one. The evidence is given by comparing the pH-dependent increment of OER on multi- and single-domain FM catalysts with or without a magnetic field. The intrinsic activity of a single-domain catalyst is higher than that of a multi-domain counterpart. The latter can be promoted to approach the former by the magnetization effect. Reducing the FM catalyst size into the single-domain region, the spin-polarized OER performance can be achieved without a magnetic field, illustrating an external magnetic field is not a requirement to reap the benefits of magnetic catalysts.

Electrochemical Testing of a New Polyimide Thin Film Electrode for Stimulation, Recording, and Monitoring of Brain Activity.

Subdural electrode arrays are used for monitoring cortical activity and functional brain mapping in patients with seizures. Until recently, the only commercially available arrays were silicone-based, whose thickness and lack of conformability could impact their performance. We designed, characterized, manufactured, and obtained FDA clearance for 29-day clinical use (510(k) K192764) of a new thin-film polyimide-based electrode array. This study describes the electrochemical characterization undertaken to evaluate the quality and reliability of electrical signal recordings and stimulation of these new arrays. Two testing paradigms were performed: a short-term active soak with electrical stimulation and a 29-day passive soak. Before and after each testing paradigm, the arrays were evaluated for their electrical performance using Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV) and Voltage Transients (VT). In all tests, the impedance remained within an acceptable range across all frequencies. The different CV curves showed no significant changes in shape or area, which is indicative of stable electrode material. The electrode polarization remained within appropriate limits to avoid hydrolysis.

A Lightweight, Elastic, and Thermally Insulating Stealth Foam With High Infrared-Radar Compatibility.

The development of infrared-radar compatible materials/devices is challenging because the requirements of material properties between infrared and radar stealth are contradictory. Herein, a composite of poly(3, 4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) coated melamine foam is designed to integrate the advantages of the dual materials and the created heterogeneous interface between them. The as-designed PEDOT:PSS@melamine composite shows excellent mechanical properties, outstanding thermal insulation, and improved thermal infrared stealth performance. The relevant superb radar stealth performance including the minimum reflection loss value of -57.57 dB, the optimum ultra-wide bandwidth of 10.52 GHz, and the simulation of radar cross section reduction value of 17.68 dB m2 , can be achieved. The optimal specific electromagnetic wave absorption performance can reach up as high as 3263.02 dB·cm3 g-1 . The average electromagnetic interference shielding effectiveness value can be 30.80 dB. This study provides an approach for the design of high-performance stealth materials with infrared-radar compatibility.

COVID-19-induced Scalp Alopecia Treated Effectively with Stem Cell Serum.

Up to 36.7% of symptomatic COVID-19 patients will have telogen effluvium (TE), which refers to diffuse scalp alopecia. With the continuing global pandemic, a review of literature reports unpredictable and incomplete recovery with conventional treatment like minoxidil. The pathogenesis of COVID-19-induced TE may be more severe than that of conventional TE as the hair follicles are proposed to be directly damaged by cytokines and thromboembolism. There is no current standardized treatment for COVID-19-induced TE. We present a patient with severe chronic TE, with no spontaneous recovery after 6 months of hair loss and minimal response to minoxidil. We commenced monthly applications of stem cell serum (Calecim). We present the results of five treatments spaced monthly, after which he experienced effective regrowth of scalp hair. We propose stem cell serum for patients who have failed conventional treatment or as an adjunct to conventional therapy in COVID-19-induced TE.

Ferromagnetic-Antiferromagnetic Coupling Core-Shell Nanoparticles with Spin Conservation for Water Oxidation.

Rational design of active oxygen evolution reaction (OER) catalysts is critical for the overall efficiency of water electrolysis. The differing spin states of the OER reactants and products is one of the factors that slows OER kinetics. Thus, spin conservation plays a crucial role in enhancing OER performance. In this work, ferromagnetic (FM)-antiferromagnetic (AFM) Fe3 O4 @Ni(OH)2 core-shell catalysts are designed. The interfacial FM-AFM coupling of these catalysts facilitates selective removal of electrons with spin direction opposing the magnetic moment of FM core, improving OER kinetics. The shell thickness is found critical in retaining the coupling effect for OER enhancement. The magnetic domain structure of the FM core also plays a critical role. With a multiple domain core, the applied magnetic field aligns the magnetic domains, optimizing the electron transport process. A significant enhancement of OER activity is observed for the multiple domain core catalysts. With a single-domain FM core with ordered magnetic dipoles, the spin-selective electron transport with minimal scattering is facilitated even without an applied magnetic field. A magnetism/OER activity model therefore hypothesizes that depends on two main parameters: interfacial spin coupling and domain structure. These findings provide new design principles for active OER catalysts.

SmCo5 with a Reconstructed Oxyhydroxide Surface for Spin-Selective Water Oxidation at Elevated Temperature.

The efficiency of electrolytic hydrogen production is limited by the slow reaction kinetics of oxygen evolution reaction (OER). Surface-reconstructed ferromagnetic (FM) catalysts with a spin-pinning effect at the FM/oxyhydroxide interface could enhance the spin-dependent OER kinetics. However, in real-life applications, electrolyzers are operated at elevated temperature, which may disrupt the spin orientations of FM catalysts and limit their performance. In this study, we prepared surface-reconstructed SmCo5 /CoOx Hy , which possesses polarized spins at the FM/oxyhydroxide interface that lead to excellent OER activity. These interfacial polarized spins could be further aligned through a magnetization process, which further enhanced the OER performance. Moreover, the operation temperature was elevated to mimic the practical operation conditions of water electrolyzers. It was found that the OER activity enhancement of the magnetized SmCo5 /CoOx Hy catalyst could be preserved up to 60 °C.

Anodic Oxidation Enabled Cation Leaching for Promoting Surface Reconstruction in Water Oxidation.

A rational design for oxygen evolution reaction (OER) catalysts is pivotal to the overall efficiency of water electrolysis. Much work has been devoted to understanding cation leaching and surface reconstruction of very active electrocatalysts, but little on intentionally promoting the surface in a controlled fashion. We now report controllable anodic leaching of Cr in CoCr2 O4 by activating the pristine material at high potential, which enables the transformation of inactive spinel CoCr2 O4 into a highly active catalyst. The depletion of Cr and consumption of lattice oxygen facilitate surface defects and oxygen vacancies, exposing Co species to reconstruct into active Co oxyhydroxides differ from CoOOH. A novel mechanism with the evolution of tetrahedrally coordinated surface cation into octahedral configuration via non-concerted proton-electron transfer is proposed. This work shows the importance of controlled anodic potential in modifying the surface chemistry of electrocatalysts.

Enhancing the Charge Transportation Ability of Yolk-Shell Structure for High-Rate Sodium and Potassium Storage.

The microstructure of large-capacity anodes is of great importance in determining the performance of sodium- and potassium-ion batteries. Yolk-shell nanostructures promise excellent structural stability but suffer from insufficient charge transfer rate during cycles. Herein, we tackle this challenge by constructing a single-walled carbon nanotube (SWNT) internally bridged yolk-shell structure, inside which SWNTs cover the surface of the yolk and connect the yolk and shell, for better electron/ion transportation. Combining the merits of both yolk-shell structure and conductive SWNT channels, the as-prepared Fe1-xS/SWNT@C composite manifests high reversible capacity and ultralong cycling stability up to 8700 cycles. Moreover, it displays the best rate capability (317 mA h g-1 at 20 A g-1 for Na+ and 236 mA h g-1 at 10 A g-1 for K+) among the reported yolk-shell structures and iron-sulfide-based anodes thus far. The kinetic analysis and density functional theory calculations further reveal that the Fe1-xS/SWNT heterointerface can effectively enhance the reversibility of K+ storage and decrease the K+ diffusion energy barrier, leading to excellent pseudocapacitive behavior and fast ion transportation for outstanding rate capability.

Antiferromagnetic Inverse Spinel Oxide LiCoVO4 with Spin-Polarized Channels for Water Oxidation.

Exploring highly efficient catalysts for the oxygen evolution reaction (OER) is essential for water electrolysis. Cost-effective transition-metal oxides with reasonable activity are raising attention. Recently, OER reactants' and products' differing spin configurations have been thought to cause slow reaction kinetics. Catalysts with magnetically polarized channels could selectively remove electrons with opposite magnetic moment and conserve overall spin during OER, enhancing triplet state oxygen molecule evolution. Herein, antiferromagnetic inverse spinel oxide LiCoVO4 is found to contain d7 Co2+ ions that can be stabilized under active octahedral sites, possessing high spin states S = 3/2 (t2g 5 eg 2 ). With high spin configuration, each Co2+ ion has an ideal magnetic moment of 3 µB , allowing the edge-shared Co2+ octahedra in spinel to be magnetically polarized. Density functional theory simulation results show that the layered antiferromagnetic LiCoVO4 studied contains magnetically polarized channels. The average magnetic moment (µave ) per transition-metal atom in the spin conduction channel is around 2.66 µB . Such channels are able to enhance the selective removal of spin-oriented electrons from the reactants during the OER, which facilitates the accumulation of appropriate magnetic moments for triplet oxygen molecule evolution. In addition, the LiCoVO4 reported has been identified as an oxide catalyst with excellent OER activity.

Probing transport limitations in thick sintered battery electrodes with neutron imaging.

Lithium-ion batteries have received significant research interest due to their advantages in energy and power density, which are important to enabling many devices. One route to further increase energy density is to fabricate thicker electrodes in the battery cell; however, careful consideration must be taken when designing electrodes as to how increasing the thickness impacts the multiscale and multiphase molecular transport processes, which can limit the overall battery operating power. Design of these electrodes necessitates probing the molecular processes when the battery cell undergoes electrochemical charge/discharge. One tool for in situ insights into the cell is neutron imaging, because neutron imaging can provide information of where electrochemical processes occur within the electrodes. In this manuscript, neutron imaging is applied to track the lithiation/delithiation processes within electrodes at different current densities for a full cell with a thick sintered Li4Ti5O12 anode and LiCoO2 cathode. The neutron imaging reveals that the molecular distribution of Li+ during discharge within the electrode is sensitive to the current density, or equivalently discharge rate. An electrochemical model provides additional insights into the limiting processes occurring within the electrodes. In particular, the impact of tortuosity and molecular transport in the liquid phase within the interstitial regions in the electrodes are considered, and the influence of tortuosity was shown to be highly sensitive to the current density. Qualitatively, the experimental results suggest that the electrodes behave consistent with the packed hard sphere approximation of Bruggeman tortuosity scaling, which indicates that the electrodes are largely mechanically intact but also that a design that incorporates tunable tortuosity could improve the performance of these types of electrodes.

Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation.

Developing highly active electrocatalysts for oxygen evolution reaction (OER) is critical for the effectiveness of water splitting. Low-cost spinel oxides have attracted increasing interest as alternatives to noble metal-based OER catalysts. A rational design of spinel catalysts can be guided by studying the structural/elemental properties that determine the reaction mechanism and activity. Here, using density functional theory (DFT) calculations, it is found that the relative position of O p-band and MOh (Co and Ni in octahedron) d-band center in ZnCo2- x Nix O4 (x = 0-2) correlates with its stability as well as the possibility for lattice oxygen to participate in OER. Therefore, it is testified by synthesizing ZnCo2- x Nix O4 spinel oxides, investigating their OER performance and surface evolution. Stable ZnCo2- x Nix O4 (x = 0-0.4) follows adsorbate evolving mechanism under OER conditions. Lattice oxygen participates in the OER of metastable ZnCo2- x Nix O4 (x = 0.6, 0.8) which gives rise to continuously formed oxyhydroxide as surface-active species and consequently enhances activity. ZnCo1.2 Ni0.8 O4 exhibits performance superior to the benchmarked IrO2 . This work illuminates the design of highly active metastable spinel electrocatalysts through the prediction of the reaction mechanism and OER activity by determining the relative positions of the O p-band and the MOh d-band center.

Equilibrium and Dynamic Absorption of Electrolyte Species in Cation/Anion Exchange Membranes of Vanadium Redox Flow Batteries.

Vanadium redox flow batteries (VRFBs) rely on ion exchange membranes (IEMs) to separate the positive and negative compartments while maintaining electrical neutrality of the cell, by allowing the transport of ionic charge carriers. Cation exchange membranes (CEMs) and anion exchange membranes (AEMs), the two principal types of IEM, have both been employed in VRFBs. The performance of these IEMs can be influenced by the absorption of species from the electrolyte. In this study, a typical commercial CEM (Nafion 117) and AEM (FAP 450), were examined with respect to vanadium uptake, after exposure to electrolyte at different states of charge. The two types of membrane were found to behave very differently, with the AEM showing very high selectivity for VV , which resulted in a significant increase in area-specific resistivity. In contrast, the CEM absorbed VII more strongly than vanadium in other oxidation states. These findings are essential for the development of an effective membrane for VRFB applications.

Antibiotic prescribing practices of emergency physicians and patient expectations for uncomplicated lacerations.

INTRODUCTION: Prophylactic antibiotics have not been found to have a benefit in the setting of uncomplicated lacerations. We evaluated the proportion of patients with uncomplicated lacerations who are prescribed prophylactic antibiotics in the emergency department (ED), factors that physicians considered when prescribing antibiotics, and factors associated with patient satisfaction. METHODS: Adults and children presenting to 10 academic EDs with acute lacerations were enrolled. Enrolled patients were interviewed before and after their physician encounter in the ED and 2 weeks later. Physicians were interviewed in the ED after the patient encounter about factors that influenced their management decisions, including their perceptions of patients' expectations. We included patients with uncomplicated lacerations (without contamination, infection, bone, tendon, or joint involvement) for analysis. RESULTS: Of 436 patients enrolled, 260 had uncomplicated lacerations, and of these, 55 (21%) were treated with antibiotics in the ED or by prescription. Physicians were more likely to use antibiotics when the wound was more than 8 hours old, involved a puncture or amputation, and when the patient lacked medical insurance. A treatment course of 7 days or greater was given to 24 of 45 patients (53%) receiving outpatient prescriptions. Patient satisfaction was not associated with antibiotic use. CONCLUSION: Antibiotics were used for about one fifth of ED patients with uncomplicated lacerations despite a lack of evidence for efficacy.

Decision instrument for the isolation of pneumonia patients with suspected pulmonary tuberculosis admitted through US emergency departments.

STUDY OBJECTIVE: Many patients with pneumonia are admitted to respiratory isolation for possible tuberculosis (TB), but most do not have active TB. We created a decision instrument to predict which pneumonia patients do not need admission to a TB isolation bed. METHODS: The design was a prospective case series conducted in 11 university-affiliated, urban, US emergency departments (EDs) (EMERGEncy ID NET). Participants were patients admitted to the hospital through the ED with a diagnosis of pneumonia or suspected TB. The main outcome measure was derivation and validation of a sensitive decision instrument to identify patients not having TB (and not requiring isolation) according to clinical data and chest radiographs. RESULTS: Of 5,079 pneumonia patients, 224 (4.4%) had pulmonary TB according to sputum cultures or tissue staining. The instrument derived to predict which patients did not have pulmonary TB included no TB history or previous positive tuberculin skin test result, nonimmigrant, not homeless, not recently incarcerated, no recent weight loss, and no apical infiltrate or cavitary lesion on plain chest radiograph. When tested on the validation subgroup, the decision instrument exhibited a negative predictive value of 99.7% (95% confidence interval [CI] 99.1% to 99.9%), and a sensitivity of 96.4% (95% CI 91.1% to 99.0%). CONCLUSION: A decision instrument can accurately predict which patients with pneumonia do not require admission to TB isolation rooms.

Antibiotic use for emergency department patients with upper respiratory infections: prescribing practices, patient expectations, and patient satisfaction.

STUDY OBJECTIVE: Physicians often prescribe antibiotics to patients even when there is no clear indication for their use. Previous studies examining antibiotic use in acute bronchitis and upper respiratory infections have been conducted in primary care settings. We evaluate the factors that physicians in the emergency department (ED) consider when prescribing antibiotics (eg, patient expectations) and the factors associated with patient satisfaction. METHODS: Ten academic EDs enrolled adults and children presenting with symptoms consistent with upper respiratory infection. Enrolled patients were interviewed before their physician encounter and were reinterviewed before discharge and 2 weeks later. Physicians were interviewed about factors that influenced their management decisions, including their perceptions of patients' expectations. Patients with a single diagnosis of uncomplicated acute bronchitis or upper respiratory infection were included for analysis. RESULTS: Of 272 patients enrolled, 68% of bronchitis patients and 9% of upper respiratory infection patients received antibiotics. Physicians were more likely to prescribe antibiotics when they believed that patients expected them (odds ratio [OR] 5.3; 95% confidence interval [CI] 2.9 to 9.6), although they were able to correctly identify only 27% of the patients who expected antibiotics. Satisfaction with the ED visit was reported by 87% of patients who received antibiotics and 89% of those not receiving antibiotics. Satisfaction with the visit was reported by 92% of patients who believed they had a better understanding of their illness but only by 72% of those who thought they had no better understanding (OR 4.4; 95% CI 2.0 to 8.4). CONCLUSION: Physicians in our academic EDs prescribed antibiotics to 68% of acute bronchitis patients and to fewer than 10% of upper respiratory infection patients. Physicians were more likely to prescribe antibiotics to patients who they believed expected them, although they correctly identified only about 1 in 4 of those patients. Patient satisfaction was not related to receipt of antibiotics but was related to the belief they had a better understanding of their illness.

Epidemiology of animal exposures presenting to emergency departments.

OBJECTIVES: To describe the epidemiology of emergency department mammalian animal exposures and to compare adult and pediatric exposure characteristics. METHODS: This was a prospective case series of patients presenting with animal exposure-related complaints from July 1996 to July 1998. Eleven university-affiliated, geographically diverse, urban emergency departments (EMERGEncy ID NET) participated. RESULTS: A total of 1,631 exposures (80.5%) were from dogs, 267 (13.2%) from cats, 88 (4.3%) from rodents or rabbits, 18 (0.9%) from raccoons and wild carnivores, eight (0.4%) from livestock, nine (0.4%) from monkeys, and five (0.2%) from bats. Compared with adults, children were more likely to be bitten by dogs (odds ratio [OR], 2.9; 95% confidence interval [CI] = 2.2 to 3.8) or hamsters, gerbils, and rabbits (OR, 2.6; 95% CI = 0.79 to 9.2); to be bitten on the head, neck, or face (OR, 6.7; 95% CI = 5.2 to 8.6); and to be petting or playing with the animal at the time of exposure (OR, 2.6; 95% CI = 2.1 to 3.3). CONCLUSIONS: Animal exposures are a common source of injury seen in the emergency department. These findings have potentially important public health implications in terms of emphasizing the need to effectively implement education programs for parents and children.

Antibiotic use for emergency department patients with acute diarrhea: Prescribing practices, patient expectations, and patient satisfaction.

STUDY OBJECTIVE: Physicians commonly prescribe antibiotics to meet patient expectations, even when antimicrobials are unnecessary. We evaluated factors emergency physicians consider in prescribing antibiotics to patients with diarrhea and examined patient expectations, physician-perceived patient expectations, and patient satisfaction. METHODS: Adults and children presenting with acute diarrhea to 1 of 10 academic emergency departments (EDs) were enrolled in this prospective observational cohort study. Adult patients and guardians of enrolled children were asked about treatment expectations before their physician encounter and about satisfaction with their medical care at discharge. Physicians were asked about factors influencing management decisions and their perceptions of patients' expectations. RESULTS: Of 104 patients enrolled, 25% received antibiotics. Physicians were more likely to prescribe antibiotics when features suggestive of bacterial enteritis were present (unadjusted odds ratio [OR] 2.5; 95% confidence interval [CI] 1.1 to 3.9). Physicians were also more likely to prescribe antibiotics when they believed patients expected them (unadjusted OR 2.3; 95% CI 1.1 to 4.4) but correctly identified such expectations in only 33% of instances. Satisfaction with care was reported by 100% of patients receiving antibiotics and 90% of those not receiving antibiotics (95% CI for difference of 10%, 3% to 17%). CONCLUSION: Physicians in academic EDs prescribe antibiotics for acute diarrhea to about 1 patient in 4 and are more likely to do so if signs or symptoms compatible with bacterial enteritis are present. Physicians' assessments of patients' expectations for therapy were accurate in only 1 of 3 patients but were nevertheless associated with antibiotic prescription. Patient satisfaction was weakly associated with receipt of antibiotics.

Neurocysticercosis in radiographically imaged seizure patients in U.S. emergency departments.

Neurocysticercosis appears to be on the rise in the United States, based on immigration patterns and published cases series, including reports of domestic acquisition. We used a collaborative network of U.S. emergency departments to characterize the epidemiology of neurocysticercosis in seizure patients. Data were collected prospectively at 11 university-affiliated, geographically diverse, urban U.S. emergency departments from July 1996 to September 1998. Patients with a seizure who underwent neuroimaging were included. Of the 1,801 patients enrolled in the study, 38 (2.1%) had seizures attributable to neurocysticercosis. The disease was detected in 9 of the 11 sites and was associated with Hispanic ethnicity, immigrant status, and exposure to areas where neurocysticercosis is endemic. This disease appears to be widely distributed and highly prevalent in certain populations (e.g., Hispanic patients) and areas (e.g., Southwest).