Film before aggregates: an operando GISAXS study on electrochemically assisted surfactant assembly.

The process of electrochemically assisted surfactant assembly was followed in real time by grazing incidence small angle X-ray scattering with the aim to deconvolute the formation of mesoporous silica film and unwanted porous particles. The X-ray technique proved to be useful for the characterisation of this process, as it takes place at a very dynamic, solid/liquid interface. This paper shows the electrochemically driven onset and evolution of silica/surfactant structures. Additional control experiments indicate the formation of vertically aligned structures without the use of an electric field, although it seems to be beneficial for increased pore ordering.

Does recovery after sport-related concussion vary by time point in a season? A multi-sport investigation.

OBJECTIVE: Seasonality, or the specific point in time within a season in which the injury occurs, may have an impact on the recovery following sport-related concussions (SRCs). In a cohort of high school athletes across multiple sports, the authors sought to investigate the impact of seasonality on 1) concussion frequency, 2) acute symptom presentation (initial Post-Concussion Symptom Scale [PCSS] score), and 3) recovery outcomes, including the time to return to learn (RTL), symptom resolution (SR), and return to play (RTP). METHODS: A retrospective, single-institution, cohort study was conducted with adolescent athletes aged 14-19 years who sustained an SRC between November 2017 and April 2022 and presented to a multidisciplinary specialty concussion clinic. The time from first practice to the end of the regular season was evenly trichotomized into early, middle, and late season. Teams that participated in the playoffs were included in a subanalysis. One-way ANOVA and independent t-tests were used to compare PCSS scores, RTL, SR, and RTP across seasonality. Univariable and multivariable regressions were used to determine predictors for recovery, defined as total days from initial visit to each outcome. RESULTS: Of the 1504 eligible athletes, 620 high school athletes met inclusion criteria; 491 (79.2%) sustained a concussion during the regular season with 73 (14.9%), 136 (27.7%), and 282 (57.4%) concussions occurring in the early, middle, and late seasons, respectively. No differences were seen for initial PCSS score, RTL, SR, or RTP across early-, middle-, and late-season concussions. The initial PCSS score was significantly higher for playoff compared with regular-season concussions (playoffs: 33.4 ± 27.5; regular season: 23.3 ± 22.8; t = -1.979, p = 0.048). A subanalysis of playoff concussions (n = 24) compared with regular-season concussions showed that concussion in the playoffs was associated with a higher initial PCSS score in univariable (ß = 0.093, p = 0.048) and multivariable (ß = 0.112, p = 0.014) analyses. CONCLUSIONS: The majority of concussions occurred during the late-season period. No difference in acute symptoms or recovery outcomes was seen when comparing the three regular season time points. Playoff concussions were associated with significantly increased symptom scores compared with nonplayoff concussions.

Combined Electrochemical, XPS, and STXM Study of Lithium Nitride as a Protective Coating for Lithium Metal and Lithium-Sulfur Batteries.

Li3N is an excellent protective coating material for lithium electrodes with very high lithium-ion conductivity and low electronic conductivity, but the formation of stable and homogeneous coatings is technically very difficult. Here, we show that protective Li3N coatings can be simply formed by the direct reaction of electrodeposited lithium electrodes with N2 gas, whereas using battery-grade lithium foil is problematic due to the presence of a native passivation layer that hampers that reaction. The protective Li3N coating is effective at preventing lithium dendrite formation, as found from unidirectional plating and plating-stripping measurements in Li-Li cells. The Li3N coating also efficiently suppresses the parasitic reactions of polysulfides and other electrolyte species with the lithium electrode, as demonstrated by scanning transmission X-ray microscopy, X-ray photoelectron spectroscopy, and optical microscopy. The protection of the lithium electrode against corrosion by polysulfides and other electrolyte species, as well as the promotion of smooth deposits without dendrites, makes the Li3N coating highly promising for applications in lithium metal batteries, such as lithium-sulfur batteries. The present findings show that the formation of Li3N can be achieved with lithium electrodes covered by a secondary electrolyte interface layer, which proves that the in situ formation of Li3N coatings inside the batteries is attainable.

LiFePO4 Battery Material for the Production of Lithium from Brines: Effect of Brine Composition and Benefits of Dilution.

Lithium battery materials can be advantageously used for the selective sequestration of lithium ions from natural resources, which contain other cations in high excess. However, for practical applications, this new approach for lithium production requires the battery host materials to be stable over many cycles while retaining the high lithium selectivity. Here, a nearly symmetrical cell design was employed to show that LiFePO4 shows good capacity retention with cycling in artificial lithium brines representative of brines from Chile, Bolivia and Argentina. A quantitative correlation was identified between brine viscosity and capacity degradation, and for the first time it was demonstrated that the dilution of viscous brines with water significantly enhanced capacity retention and rate capability. The electrochemical and X-ray diffraction characterisation of the cycled electrodes also showed that the high lithium selectivity was preserved with cycling. Raman spectra of the cycled electrodes showed no signs of degradation of the carbon coating of LiFePO4 , while scanning electron microscopy images showed signs of particle cracking, thus pointing towards interfacial reactions as the cause of capacity degradation.

Elevated serum antibody responses to synthetic mycobacterial lipid antigens among UK farmers: an indication of exposure to environmental mycobacteria?

Background: mycobacterial cells contain complex mixtures of mycolic acid esters. These can be used as antigens recognised by antibodies in the serum of individuals with active tuberculosis, caused by Mycobacterium tuberculosis. In high burden populations, a significant number of false positives are observed; possibly these antigens are also recognised by antibodies generated by other mycobacterial infections, particularly ubiquitous 'environmental mycobacteria'. This suggests similar responses may be observed in a low burden TB population, particularly in groups regularly exposed to mycobacteria. Methods: ELISA using single synthetic trehalose mycolates corresponding to major classes in many mycobacteria was used to detect antibodies in serum of individuals with no known mycobacterial infection, comprising farmers, abattoir workers, and rural and urban populations. Results: serum from four Welsh or Scottish cohorts showed lower (with some antigens significantly lower) median responses than those reported for TB negatives from high-burden TB populations, and significantly lower responses than those with active TB. A small fraction, particularly older farmers, showed strong responses. A second study examined BCG vaccinated and non-vaccinated farmers and non-farmers. Farmers gave significantly higher median responses than non-farmers with three of five antigens, while there was no significant difference between vaccinated or non-vaccinated for either farmer or non-farmer groups. Conclusions: this initial study shows that serodiagnosis with mycobacterial lipid antigens can detect antibodies in a population sub-group that is significantly exposed to mycobacteria, in an assay that is not interfered with by vaccination. Given the links between mycobacterial exposure and a range of immune system diseases, further understanding such responses may provide a new opportunity for monitoring public health and directing treatment.

Pressure-Tuneable Visible-Range Band Gap in the Ionic Spinel Tin Nitride.

The application of pressure allows systematic tuning of the charge density of a material cleanly, that is, without changes to the chemical composition via dopants, and exploratory high-pressure experiments can inform the design of bulk syntheses of materials that benefit from their properties under compression. The electronic and structural response of semiconducting tin nitride Sn3 N4 under compression is now reported. A continuous opening of the optical band gap was observed from 1.3 eV to 3.0 eV over a range of 100 GPa, a 540 nm blue-shift spanning the entire visible spectrum. The pressure-mediated band gap opening is general to this material across numerous high-density polymorphs, implicating the predominant ionic bonding in the material as the cause. The rate of decompression to ambient conditions permits access to recoverable metastable states with varying band gaps energies, opening the possibility of pressure-tuneable electronic properties for future applications.