Search

The synthesis and characterization of the lithium m‐terphenylhydridoborates [Li(2,6‐Mes2C6H3)BH3]2 (1), Li(2,6‐Mes2C6H3)2BH2 (2) and Li(OEt2)(2,6‐Mes2C6H3)2BH2 (3) are reported. Hirshfeld Atom Refinement (HAR) of the experimentally obtained molecular structures by single‐crystal X‐ray crystallography allowed the determination of the exact positions of the hydrogen atoms. The bond situations of the various B−H⋅⋅⋅Li linkages were investigated by a complementary bonding analysis using various methods including atoms in molecules (AIM), electron localizability indicator (ELI−D), non‐covalent interaction (NCI) index and the compliance matrix. [ABSTRACT FROM AUTHOR]

We assess the prevalence of ducted and non‐ducted whistler propagation using burst mode data from the Van Allen Probes Electric Field and Waves instrument (EFW). We have identified burst periods containing lightning‐generated whistlers (LGWs), resulting in a data set available for future use. The entire burst data set is filtered through an analysis of the search coil magnetometer (SCM) noise, identifying signals in frequency space that exceed an adaptive noise threshold. We implement DBSCAN (Density‐Based Spatial Clustering of Applications with Noise) to identify individual whistlers and clusters of whistlers. With magnetic spectral analysis, we calculate the mean wave normal angle (WNA) for each LGW group. We use ray tracing to estimate the expected WNA distributions for non‐ducted LGWs to compare to the data and determine methods for identifying potentially ducted LGWs. The ray‐tracing results provide a clear threshold in WNA for ducted whistlers. Using this threshold, we estimate that at least 10.1% $10.1\%$ of LGWs in this data set are ducted. We find that the majority of potentially ducted whistlers are below L=2 $L=2$ and nearly half of LGWs below L=2 $L=2$ and within 9–18 MLT may be ducted. Plain Language Summary: Lightning‐generated whistlers (LGWs) are very‐low‐frequency waves produced when lightning‐generated radio pulses known as sferics excite whistler mode waves through the ionosphere and into the magnetosphere. LGW wave power contributes to pitch angle scattering and precipitation of trapped energetic electrons, affecting atmospheric chemistry and helping maintain the slot region between the radiation belts. Field‐aligned plasma density irregularities, or ducts, affect the propagation of LGWs. Ducting can determine where the wave energy travels, how long it persists, and which energetic particle populations are affected. We present distributions of LGW wave properties and explore methods of determining ducting of LGWs. Key Points: We present a complete Van Allen Probes Electric Field & Waves whistler data set generated through density‐based clusteringMost whistlers in this data set have high wave normal angles consistent with non‐ducted propagationLikely ducted whistlers are mainly below L=2 $L=2$; about half of whistlers between 9 and 18 MLT and below L=2 $L=2$ are likely ducted [ABSTRACT FROM AUTHOR]

Whistler‐mode hiss waves are crucial to the dynamics of Earth's radiation belts, particularly in the scattering and loss of energetic electrons and forming the slot region between the inner and outer belts. The generation of hiss waves involves multiple potential mechanisms, which are under active research. Understanding the role of hiss waves in radiation belt dynamics and their generation mechanisms requires analyzing their temporal and spatial evolutions, especially for strong hiss waves. Therefore, we developed an Imbalanced Regressive Neural Network (IR‐NN) model for predicting hiss amplitudes. This model addresses the challenge posed by the data imbalance of the hiss data set, which consists of predominantly quiet‐time background samples and fewer but significant active‐time intense hiss samples. Notably, the IR‐NN hiss model excels in predicting strong hiss waves (>100 pT). We investigate the temporal and spatial evolution of hiss wave during a geomagnetic storm on 24–27 October 2017. We show that hiss waves occur within the nominal plasmapause, and follow its dynamically evolving shape. They exhibit intensifications with 1 and 2 hr timescale similar to substorms but with a noticeable time delay. The intensifications begin near dawn and progress toward noon and afternoon. During the storm recovery phase, hiss intensifications may occur in the plume. Additionally, we observe no significant latitudinal dependence of the hiss waves within |MLAT| < 20°. In addition to describing the spatiotemporal evolution of hiss waves, this study highlights the importance of imbalanced regressive methods, given the prevalence of imbalanced data sets in space physics and other real‐world applications. Plain Language Summary: Whistler‐mode hiss waves play a crucial role in understanding the dynamics of Earth's radiation belts, particularly scattering and loss of energetic electrons and the formation of the slot region. The underlying generation mechanisms of hiss wave sources remain an active area of research, which needs to quantify the global evolution of these waves, especially powerful ones. We developed an Imbalanced Regressive Neural Network (IR‐NN) model, which excels at accurately predicting strong hiss wave activity, that is of particular interest in radiation belt studies. We analyzed the evolution of hiss waves during a geomagnetically active period in October 2017. We found that these waves predominantly occur within the plasmapause boundary and exhibit dynamics that follow the plasmapause's changes. These waves strengthen on timescales similar to those of magnetospheric substorms, with a slight delay, and move to different local times during different phases of the storm. These waves maintain uniform intensity across low to mid‐latitudes. This study underlines the importance of imbalanced regressive methods in handling imbalanced data sets, a common challenge in space physics and related physical science fields. This approach is not only significant for advancing our understanding of space weather phenomena but also has broader implications in other areas. Key Points: An imbalanced regressive neural network model of hiss amplitude developed that predicts quiet‐time background and active‐time intense wavesHiss waves are well organized inside the plasmapause and follow its dynamic shape, evolving from dawn toward later local time during a stormModeled hiss evolution correlates with chorus, supporting the hypothesis that hiss is generated by evolving chorus waves [ABSTRACT FROM AUTHOR]

We use the full NASA Van Allen Probes mission (2012–2019) to extract the electron plasma density from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) and Electric Field and Waves (EFW) instruments and discuss the evolution of the plasmasphere. We generate new statistics including mean and standard deviations of the plasma density with respect to L‐shell, magnetic local time (MLT), and various geomagnetic indices. These statistics are generated to be applied in radiation belt physics and space weather codes (with fits provided). The mean plasmasphere is circular around Earth with respect to MLT for Kp < 1. The mean 100 cm−3 level line is above L = 5 and mean 10 cm−3 level expands above the Van Allen Probes apogee for Kp < 1. The outer electron belt lies within the plasmasphere for 60% of all times. As activity increases (Kp > 2), a gradual MLT asymmetry forms with higher mean density in the afternoon sector due to plumes expanding outward. Conversely, the mean density decreases on the dawn and night sectors. The mean density is between ∼500 and ∼50 cm−3 between L ∼ 4 and L ∼ 6 during quiet and moderately active times (Kp < 3), representing ∼80% of all times. Statistics in regions of high density below L = 2 are underdefined for intense activity. The highest standard deviation of density represents a factor 2.5 to 3 times the mean above L = 5 and for active times. We find the percent difference between the EFW and EMFISIS densities is bounded by ±20% for quiet and moderate activity (Kp < 5) and goes up to ±100% for extreme activity. Plain Language Summary: The Earth's plasmasphere, discovered in the 1950s, is a region of cold plasma made of ions and electrons of a few electronvolts in energy, originating from upwelling ionized gas from the ionosphere and forming a rotating torus around the Earth. The radial profile of the electron cold plasma density within the plasmasphere decays from 10,000 electrons per cubic centimeter at ∼1,000 km altitude to 10s electrons per cubic centimeter at its outer edge, sometimes exceeding ∼36,000 km in altitude at the equator. The state of the plasmasphere is highly dependent on geomagnetic conditions, with geomagnetic storms and substorms eroding parts of this plasma. Here, we analyze 7 years of NASA Van Allen Probes measurements of the electron plasma density and generate statistics with respect to L‐shell, magnetic local time, and geomagnetic indices. In this way, we show statistical variations of the plasmasphere, a strong magnetic local time dependence, and erosion with increasing geomagnetic activity. New mean electron densities and their standard deviation are generated and fitted with model functions that can be incorporated into space weather codes. This is important because the electron density is a key parameter influencing the strength of wave‐particle interactions that accelerate and scatter energetic particles in the inner magnetosphere. Key Points: Generation of new statistics of mean and standard deviation of the plasma density from Electric Field and Waves and Electric and Magnetic Field Instrument Suite and Integrated Science of RBSP for the whole missionEmpirical density models made of fits are provided versus L‐shell, magnetic local time (MLT), and geomagnetic indices to be used in radiation belt codesAn extensive analysis of the cold plasma statistics is provided with respect to L‐shell, MLT, and geomagnetic activity [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease. The immunosuppressive functions of regulatory T lymphocytes (Tregs) are impaired in ALS, and correlate to disease progression. The phase 2a IMODALS trial reported an increase in Treg number in ALS patients following the administration of low‐dose (ld) interleukin‐2 (IL‐2). We propose a pharmacometabolomics approach to decipher metabolic modifications occurring in patients treated with ld‐IL‐2 and its relationship with Treg response. Blood metabolomic profiles were determined on days D1, D64, and D85 from patients receiving 2 MIU of IL‐2 (n = 12) and patients receiving a placebo (n = 12). We discriminated the three time points for the treatment group (average error rate of 42%). Among the important metabolites, kynurenine increased between D1 and D64, followed by a reduction at D85. The percentage increase of Treg number from D1 to D64, as predicted by the metabolome at D1, was highly correlated with the observed value. This study provided a proof of concept for metabolic characterization of the effect of ld‐IL‐2 in ALS. These data could present advances toward a personalized medicine approach and present pharmacometabolomics as a key tool to complement genomic and transcriptional data for drug characterization, leading to systems pharmacology. [ABSTRACT FROM AUTHOR]

We demonstrate the formation of supramolecular nanotubes from molecular triangles in a single crystal by balancing the hydrogen bonds and halogen interactions between individual macrocycles. Thereby, we template the supramolecular nanotube growth by intermolecular interactions encoded directly in the macrocycles instead of those provided by the crystallization solvent. Ultimately, we show that replacing bromines for iodines in the macrocycle is necessary to achieve this supramolecular organization by enhancing the strength of the halogen interactions and concomitant reduction of the detrimental hydrogen bonds. We investigated the nature and the interplay of the individual intermolecular interactions by analysis of the experimental single crystal data and quantum chemical calculations. This work enriches the available toolbox of supramolecular interactions and will aid and abet the development of rationally‐designed materials with a long‐range 1D tubular organization. [ABSTRACT FROM AUTHOR]

Dynamic bonds are essential structural ingredients of dynamic covalent chemistry that involve reversible cleavage and formation of bonds. Herein, we explore the electronic characteristics of Se−N bonds in the organo‐selenium antioxidant ebselen and its derivatives for their propensity to function as dynamic covalent bonds by employing high‐resolution X‐ray quantum crystallography and complementary computational studies. An analysis of the experimentally reconstructed X‐ray wavefunctions reveals the salient electronic features of the Se−N bonds with very low electron density localized at the bonding region and a positive Laplacian value at the bond critical point. Bond orders and percentage covalency and ionicity estimated from the X‐ray wavefunctions, along with localized orbital locator (LOL) and electron localization function (ELF) analyses show that the Se−N bond is unique in its closed shell‐like features, despite being a covalent bond. Time‐dependent DFT calculations simulate the cleavage of Se−N bonds in ebselen in the excited state, further substantiating their nature as dynamic bonds. [ABSTRACT FROM AUTHOR]

An unusually low density solar wind event was observed in December 2022 moving past both Earth and Mars. The source was traced back to a coronal hole and active region on the Sun's surface. The resulting solar wind lead to the development of a co‐rotating interaction region (CIR) and trailing rarefaction region that lasted for multiple solar rotations. Within this structure, the solar wind conditions, including density, velocity, and magnetic field magnitude and orientation drastically changed. In this study we analyze the response of the Martian ionosphere using MAVEN data to these changing solar wind conditions. The low density solar wind region associated with the December event resulted in the expansion of the Martian ionospheric boundaries. We show that the ion composition boundary (ICB) is located at extreme altitudes that are beyond previously observed locations from the MAVEN mission between 2015 and 2018. Furthermore, the boundary between shocked solar wind and the Martian ionosphere identified using electron and ion data moved together on the dayside of the planet with the changing solar wind conditions. However, at the flank region these boundaries do not move together, and we show here that the decoupling of the two boundaries may be the result of a change in the interplanetary magnetic field azimuthal angle. Plain Language Summary: The Sun constantly emits fast moving charged particles into interplanetary space in what is known as the solar wind. In December 2022, a region of fast moving solar wind overtook a region of slower moving solar wind. The fast solar wind acted as a broom sweeping up and compressing the slower wind preceding it. This interaction of two solar wind speeds is observed to rotate with the Sun. Trailing this interaction region is a region of low density solar wind. In December 2022, this type of interplanetary solar wind structure interacted with Mars' electrically charged atmosphere, or ionosphere. Throughout this period, the ionosphere boundary characterized by a transition from solar wind ions to planetary ions moved up and down relative to the planet near dusk. As the rarefaction region passed through the system, the ionosphere expanded to unusually high heights as it was not compressed by the solar wind. However, the flapping of the ionospheric boundary seems to depend on the orientation that the solar wind interacts with Mars. Key Points: The disappearing solar wind event observed at Mars in December 2022 was caused by a co‐rotating interaction regionMars' ionosphere expanded further than previously observed locations between 2015 through 2018The flank ion composition boundary experiences large fluctuations in altitude after a change in the interplanetary magnetic field direction [ABSTRACT FROM AUTHOR]

The interaction of intense synchrotron radiation with molecular crystals frequently modifies the crystal structure by breaking bonds, producing fragments and, hence, inducing disorder. Here, a second‐rank tensor of radiation‐induced lattice strain is proposed to characterize the structural susceptibility to radiation. Quantitative estimates are derived using a linear response approximation from experimental data collected on three materials Hg(NO3)2(PPh3)2, Hg(CN)2(PPh3)2 and BiPh3 [PPh3 = triphenylphosphine, P(C6H5)3; Ph = phenyl, C6H5], and are compared with the corresponding thermal expansivities. The associated eigenvalues and eigenvectors show that the two tensors are not the same and therefore probe truly different structural responses. The tensor of radiative expansion serves as a measure of the susceptibility of crystal structures to radiation damage. [ABSTRACT FROM AUTHOR]

Catalytic C−N bond formation by direct activation of C−H bonds offers wide synthetic potential. En route to C−H amination, complexes with organic azides are critical precursors towards the reactive nitrene intermediate. Despite their relevance, α‐N coordinated organoazide complexes are scarce in general, and elusive with iron, although iron complexes are by far the most active catalysts for C−H amination with organoazides. Herein, we report the synthesis of a stable iron α‐N coordinated organoazide complex from [Fe(N(SiMe3)2)2] and AdN3 (Ad=1‐adamantyl) and its crystallographic, IR, NMR and zero‐field 57Fe Mössbauer spectroscopic characterization. These analyses revealed that the organoazide is in fast equilibrium between the free and coordinated state (Keq=62). Photo‐crystallography experiments showed gradual dissociation of N2, which imparted an Fe−N bond shortening and correspond to structural snapshots of the formation of an iron imido/nitrene complex. Reactivity of the organoazide complex in solution showed complete loss of N2, and subsequent formation of a C−H aminated product via nitrene insertion into a C−H bond of the N(SiMe3)2 ligand. Monitoring this reaction by 1H NMR spectroscopy indicates the transient formation of the imido/nitrene intermediate, which was supported by Mössbauer spectroscopy in frozen solution. [ABSTRACT FROM AUTHOR]

Currently, only Apis mellifera is used in environmental regulation to evaluate the hazard of pesticides to pollinators. The low representativeness of pollinators and bee diversity in this approach may result in insufficient protection for the wild species. This scenario is intensified in tropical environments, where little is known about the effects of pesticides on solitary bees. We aimed to calculate the medium lethal dose (LD50) and medium lethal concentration (LC50) of the insecticide dimethoate in the Neotropical solitary bee Centris analis, a cavity‐nesting, oil‐collecting bee distributed from Brazil to Mexico. Males and females of C. analis were exposed orally to dimethoate for 48 h under laboratory conditions. Lethality was assessed every 24 h until 144 h after the beginning of the test. After the LD50 calculation, we compared the value with available LD50 values in the literature of other bee species using the species sensitivity distribution curve. In 48 h of exposure, males showed an LD50 value 1.33 times lower than females (32.78 and 43.84 ng active ingredient/bee, respectively). Centris analis was more sensitive to dimethoate than the model species A. mellifera and the solitary bee from temperate zones, Osmia lignaria. However, on a body weight basis, C. analis and A. mellifera had similar LD50 values. Ours is the first study that calculated an LD50 for a Neotropical solitary bee. Besides, the results are of crucial importance for a better understanding of the effects of pesticides on the tropical bee fauna and will help to improve the risk assessment of pesticides to bees under tropical conditions, giving attention to wild species, which are commonly neglected. Environ Toxicol Chem 2023;42:2758–2767. © 2023 SETAC [ABSTRACT FROM AUTHOR]

The occurrence of Venusian lighting has been debated for decades. Terrestrial lightning generates whistler waves, and many whistlers have been observed in Venus's ionosphere and induced magnetosphere. Venusian lightning occurrence rates derived from these whistler observations are relatively high. However, optical flashes on Venus are exceedingly rare and Venus encounters by multiple spacecrafts have not detected lightning. These non‐detections and rare optical observations are consistent with low Venusian lightning occurrence rates, which is incompatible with the high whistler‐derived rates. We present observations of whistlers during a Parker Solar Probe Venus gravity assist and eliminate lightning as a possible source. These waves are observed at an altitude of 0.39 Venus radii on Venus' nightside with planetward propagation and are simultaneous with Langmuir waves. This provides a mechanism for whistler generation near Venus that does not require lightning, and suggests that whistler‐based lightning occurrence rates may be overestimated. Plain Language Summary: Whistler waves are a type of plasma wave. These waves can be generated in several ways, including by lightning. Every lightning strike on Earth generates a whistler wave, but only some of the whistler waves in near‐Earth space are generated by lightning. Many whistler waves have been detected near Venus and have been used to argue that lightning likely occurs on Venus at a relatively high rate. However, other signatures of lightning (including flashes of light in the sky) on Venus are very rare, which indicates that Venusian lightning must occur at a very low rate. The discrepancy between these different signatures of lightning on Venus means that we do not know how often Venus actually experiences lightning. We use data from Parker Solar Probe during a Venus gravity assist to study whistler waves that occurred on the nightside of Venus, very close to the planet. We observe that these waves are traveling toward Venus, which means they could not have been generated by lightning. This shows that whistler waves can occur near Venus without being generated by lightning and indicates that the occurrence rates of Venusian lightning based on whistler wave observations might be overestimated. Key Points: Whistler waves were observed at an altitude of 0.39 Venus radii on Venus's nightside with planetward Poynting vectorLangmuir waves occurred simultaneously with the whistlers, suggesting electron beam driving with magnetotail originsLightning is eliminated as a possible generation mechanism for these whistler waves [ABSTRACT FROM AUTHOR]

The purpose of this paper is to study minimal monads associated to a rank two vector bundle E${\mathcal {E}}$ on Pn$ {\mathbf {P}}^{n}$. In particular, we study situations where E${\mathcal {E}}$ has H∗i(E)=0$H^i_*({\mathcal {E}}) =0$ for 1

Whistler‐mode chorus waves play an essential role in the acceleration and loss of energetic electrons in the Earth's inner magnetosphere, with the more intense waves producing the most dramatic effects. However, it is challenging to predict the amplitude of strong chorus waves due to the imbalanced nature of the data set, that is, there are many more non‐chorus data points than strong chorus waves. Thus, traditional models usually underestimate chorus wave amplitudes significantly during active times. Using an imbalanced regressive (IR) method, we develop a neural network model of lower‐band (LB) chorus waves using 7‐year observations from the EMFISIS instrument onboard Van Allen Probes. The feature selection process suggests that the auroral electrojet index alone captures most of the variations of chorus waves. The large amplitude of strong chorus waves can be predicted for the first time. Furthermore, our model shows that the equatorial LB chorus's spatiotemporal evolution is similar to the drift path of substorm‐injected electrons. We also show that the chorus waves have a peak amplitude at the equator in the source MLT near midnight, but toward noon, there is a local minimum in amplitude at the equator with two off‐equator amplitude peaks in both hemispheres, likely caused by the bifurcated drift paths of substorm injections on the dayside. The IR‐based chorus model will improve radiation belt prediction by providing chorus wave distributions, especially storm‐time strong chorus. Since data imbalance is ubiquitous and inherent in space physics and other physical systems, imbalanced regressive methods deserve more attention in space physics. Plain Language Summary: Whistler‐mode chorus waves are essential in accelerating radiation belt electrons. However, predicting the amplitude of strong chorus waves is difficult because of their imbalanced nature. In other words, there are many more observations of no‐chorus waves than strong chorus waves. A consequence is that these no‐chorus wave data dominate traditional models, so these models usually predict values that are too small for strong waves. Using an imbalanced regressive method, we developed a machine learning (ML) model of lower‐band chorus wave amplitude. For the first time, the ML‐chorus model can predict the amplitude of strong chorus waves. The ML‐chorus model shows the evolution of the chorus wave at the equator, similar to the drift path of injected electrons, which brings electron anisotropy that generates chorus waves. The ML‐chorus model shows that the chorus waves are stronger at the equator near midnight, the source region of plasma injection. Away from midnight, the chorus waves have an equatorial minimum instead. Our chorus model will improve the forecast of the radiation belt environment by providing chorus wave distributions, especially large‐amplitude strong chorus during geomagnetic storms. Because data imbalance is commonly seen in space physics and other physical systems, imbalanced regressive methods require more attention. Key Points: A neural network model of lower‐band chorus wave amplitude is developed using imbalanced regressionFor the first time, a chorus model can predict the large amplitude of strong chorus wavesChorus' evolution is consistent with electron injection drift paths, peak equatorial amplitude near midnight, and off‐equator peaks at noon [ABSTRACT FROM AUTHOR]

The search‐coil magnetometer (SCM) aboard Parker Solar Probe (PSP) measures the 3 Hz to 1 MHz magnetic field fluctuations. During Encounter 1, the SCM operated as expected; however, in March 2019, technical issues limited subsequent encounters to two components for frequencies below 1 kHz. Detrimentally, most whistler waves are observed in the affected frequency band where established techniques cannot extract the wave polarization properties under these conditions. Fortunately, the Electric Field Instrument aboard PSP measures two electric field components and covers the affected bandwidth. We propose a technique using the available electromagnetic fields to reconstruct the missing components by neglecting the electric field parallel to the background magnetic field. This technique is applicable with the assumptions of (a) low‐frequency whistlers in the plasma frame relative to the electron cyclotron frequency; (b) a small propagation angle with respect to the background magnetic field; and (c) a large wave phase speed relative to the cross‐field solar wind velocity. Critically, the method cannot be applied if the background magnetic field is aligned with the affected SCM coil. We have validated our method using burst mode measurements made before March 2019. The reconstruction conditions are satisfied for 80% of the burst mode whistlers detected during Encounter 1. We apply the method to determine the polarization of a whistler event observed after March 2019 during Encounter 2. Our novel method is an encouraging step toward analyzing whistler properties in affected encounters and improving our understanding of wave‐particle interactions in the young solar wind. Key Points: We present a method to determine whistler wave polarization without a magnetic field component (Parker Solar Probe regime after March 2019)This allows us to expand whistler wave statistical databases; this is an essential step to better understanding wave‐particle interactionsWe demonstrate that this method applies to 80% of whistler waves observed in burst‐mode data from the first encounter [ABSTRACT FROM AUTHOR]

Aims: This study aimed to explore the non‐linear relationships between cell‐free microRNAs (miRNAs) and their contribution to prediction of Frontotemporal dementia (FTD), an early onset dementia that is clinically heterogeneous, and too often suffers from delayed diagnosis. Methods: We initially studied a training cohort of 219 subjects (135 FTD and 84 non‐neurodegenerative controls) and then validated the results in a cohort of 74 subjects (33 FTD and 41 controls). Results: On the basis of cell‐free plasma miRNA profiling by next generation sequencing and machine learning approaches, we develop a non‐linear prediction model that accurately distinguishes FTD from non‐neurodegenerative controls in ~90% of cases. Conclusions: The fascinating potential of diagnostic miRNA biomarkers might enable early‐stage detection and a cost‐effective screening approach for clinical trials that can facilitate drug development. [ABSTRACT FROM AUTHOR]

Agostic interactions involving titanium are textbook examples for C−H bond activation. Therefore, it is surprising that there is no study in the literature in which the hydrogen atom in the C−H⋅⋅⋅Ti interaction has been determined reliably, although nearly all the criteria for assessing the strength and character of the agostic interaction depend on the hydrogen atom and its position. Here, we demonstrate with quantum crystallographic techniques how hydrogen atoms in a series of three titanium amides can indeed be localized accurately and precisely based on routine single‐crystal X‐ray diffraction data. Once the hydrogen positions have been established, theoretical and experimentally fitted bonding analyses reveal that the C−H⋅⋅⋅Ti interaction becomes stronger with increasing inter‐ligand London dispersion stabilization of bulky alkyl groups. [ABSTRACT FROM AUTHOR]

NASA's Van Allen Probes observed significant, long‐lived fluxes of inner belt electrons up to ∼1 MeV after geomagnetic storms in March and June 2015. Reanalysis of Magnetic Electron Ion Spectrometer (MagEIS) data with improved background correction showed a clearer picture of the relativistic electron population that persisted through 2016 and into 2017 above the Fennell et al. (2015, https://doi.org/10.1002/2014gl062874) limit. The intensity and duration of these enhancements allow estimation of decay timescales for comparison with simulated decay rates and theoretical lifetimes. We compare decay timescales from these data and DREAM3D simulations based on them using geomagnetic activity‐dependent pitch angle diffusion coefficients derived from plasmapause‐indexed wave data (Malaspina et al., 2016, https://doi.org/10.1002/2016gl069982, 2018, https://doi.org/10.1029/2018gl078564) and phase space densities derived from MagEIS observations. Simulated decay rates match observed decay rates more closely than the theoretical lifetime due to significantly nonequilibrium pitch angle distributions in simulation and data. We conclude that nonequilibrium effects, rather than a missing diffusion or loss process, account for observed short decay rates. Plain Language Summary: Earth's radiation belts are influenced by a wide variety of source and loss processes, so it is difficult to model and forecast its evolution or predict its effects on spaceborne assets. Decay timescales for loss processes are essential to understanding this balance, but the theoretical predictions for these timescales in the inner radiation belt can exceed the observed decay times by an order of magnitude or more. We have observed and simulated an exceptional period of radiation belt injection and decay to understand this discrepancy. We have found that changes in the wave properties due to geomagnetic activity can account for the difference: changes in the equilibrium distribution associated with the wave environment result in consistent refilling of non‐equilibrium modes that decay much faster than the equilibrium mode. Key Points: DREAM3D simulations of Earth's inner electron belt, based on Van Allen Probes observations, are carried out to evaluate model decay ratesPitch angle diffusion using coefficients reflecting geomagnetic activity demonstrates realistic decay ratesDecay rates extracted with a Random Sample Consensus‐based algorithm from modeled and observed fluxes agree, while theoretical lifetimes are too long [ABSTRACT FROM AUTHOR]

Electric field instruments carried by spacecraft (SC) are complementary to dedicated dust detectors by registering transient voltage perturbations caused by impact-generated plasma. The signal waveform contains information about the interaction between the impact-generated plasma cloud and the elements of SC-antenna system. The variability of antenna signals from dust impacts has not yet been systematically characterized. A set of laboratory measurements are performed to characterize signal variations in response to SC parameters (bias voltage and antenna configuration) and impactor parameters (impact speed and composition). The measurements demonstrate that dipole antenna configurations are sensitive to dust impacts and that the detected signals vary with impact location. When dust impacts occur at low speeds, the antennas typically register smaller amplitudes and less characteristic impact signal shapes. In this case, impact event identification may be more challenging due to lower signal-to-noise ratios and/or more variable waveforms shapes, indicating the compound nature of nonfully developed impact-generated plasmas. To investigate possible variations in the impacting materials, the measurements are carried out using two dust samples with different mass densities: iron and aluminum. No significant variations of the measured waveform or plasma parameters obtained from data analysis are observed between the two materials used. [ABSTRACT FROM AUTHOR]

A new empirical density model is developed for the inner zone between 1 < L < 3 using plasma densities inferred from the upper hybrid resonance on Arase, and hiss‐inferred density values from Van Allen Probes. The Van Allen Probes hiss‐inferred densities are first recalibrated and validated against Arase observations, using both a conjunction event and statistical analyses. The newly developed density model includes dependencies on L, magnetic latitude, and magnetic local time (MLT). Between 1.5 < L < 3.0, the equatorial density variation with L is shown to be equivalent to that of the Ozhogin et al. (2012, https://doi.org/10.1029/2011JA017330) model. However, for L < 1.5, this dependence changes as the plasma density increases at a faster rate with decreasing L. The latitudinal dependence of the plasma density is shown to present a flatter profile than previous models, meaning lower densities extend to higher latitudes. This dependence is well‐modeled by updated fitting coefficients. A clear MLT dependence of the plasma density is identified, which was not found or included in some previous models. This variation is consistent with the diurnal variation of the ionosphere, peaking near MLT = 14 and becoming larger in amplitude with decreasing L. A function describing this MLT dependence is presented. Overall, the new L, latitude, and MLT‐dependent empirical model can provide density values in areas outside the validity region of many previous models, making it a useful resource for accurately determining diffusion coefficients and predicting electron dynamics and their lifetimes in the inner radiation belt. Key Points: Radiation Belt Storm Probes and Arase data are used to build a new empirical plasma density model for the inner zone, including L, latitude, and magnetic local time (MLT) dependenciesMLT dependence consistent with diurnal variation of ionosphere. Variation is largest in amplitude at low L, but persists out to L = 3New model provides density in areas outside previous model bounds, making it a useful resource for modeling inner radiation belt dynamics [ABSTRACT FROM AUTHOR]

In a combined experimental and computational study, the molecular and electronic structures of the divalent bis(m‐terphenyl)element cations [(2,6‐Mes2C6H3)2E]+ of group 13 (1, E=B; 2, E=Al; 3, E=Ga; 4, E=In; 5, E=Tl) were investigated. The preparation and characterization of 2, 3 and 5 were previously reported by Wehmschulte's (Organometallics2004, 23, 1965–1967; J. Am. Chem. Soc. 2003, 125, 1470–1471) and our groups (Organometallics2009, 28, 6893–6901). The indinium ion 4 was prepared and fully characterized for the first time. Attempts to prepare the borinium ion 1 by fluoride or hydride abstraction were unsuccessful. The electronic structures of 1–5 and the stabilization by the bulky m‐terphenyl substituents were analyzed using quantum chemical calculations and compared to the divalent bis(m‐terphenyl)pnictogenium ions [(2,6‐Mes2C6H3)2E]+ of group 15 (6, E=P; 7, E=As; 8, E=Sb; 9, E=Bi) previously investigated by our group (Angew. Chem. Int. Ed. 2018, 57, 10080–10084). The calculated fluoride ion affinities (FIA) of 1–9 are higher than that of SbF5, which classifies them as Lewis superacids. [ABSTRACT FROM AUTHOR]

Previous statistical studies of plasmaspheric hiss investigated the averaged shape of the magnetic field power spectra at various points in the magnetosphere. However, this approach does not consider the fact that very diverse spectral shapes exist at a given L‐shell and magnetic local time. Averaging the data together means that important features of the spectral shapes are lost. In this paper, we use an unsupervised machine learning technique to categorize plasmaspheric hiss. In contrast to the previous studies, this technique allows us to identify power spectra that have "similar" shapes and study their spatial distribution without averaging together vastly different spectral shapes. We show that strong negative correlations exist between the hiss frequency and bandwidth. Key Points: Unsupervised machine learning is used to categorize hiss power spectra of the electric field from Van Allen ProbesFrom the pre‐noon sector toward the afternoon sector the hiss frequency decreases while the bandwidth increasesWe discuss possible source mechanisms that are consistent with the spatial distribution of the hiss waves [ABSTRACT FROM AUTHOR]

Background and purpose: This study was undertaken to explore associations between plasma neurofilament light chain (pNfL) concentration (pg/ml) and disease activity in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and examine the usefulness of pNfL concentrations in determining disease remission. Methods: We examined pNfL concentrations in treatment‐naïve CIDP patients (n = 10) before and after intravenous immunoglobulin (IVIg) induction treatment, in pNfL concentrations in patients on maintenance IVIg treatment who had stable (n = 15) versus unstable disease (n = 9), and in clinically stable IVIg‐treated patients (n = 10) in whom we suspended IVIg to determine disease activity and ongoing need for maintenance IVIg. pNfL concentrations in an age‐matched healthy control group were measured for comparison. Results: Among treatment‐naïve patients, pNfL concentration was higher in patients before IVIg treatment than healthy controls and subsequently reduced to be comparable to control group values after IVIg induction. Among CIDP patients on IVIg treatment, pNfL concentration was significantly higher in unstable patients than stable patients. A pNFL concentration > 16.6 pg/ml distinguished unstable treated CIDP from stable treated CIDP (sensitivity = 86.7%, specificity = 66.7%, area under receiver operating characteristic curve = 0.73). Among the treatment withdrawal group, there was a statistically significant correlation between pNfL concentration at time of IVIg withdrawal and the likelihood of relapse (r = 0.72, p < 0.05), suggesting an association of higher pNfL concentration with active disease. Conclusions: pNfL concentrations may be a sensitive, clinically useful biomarker in assessing subclinical disease activity. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease among adults. With diagnosis reached relatively late into the disease process, extensive motor cell loss narrows the window for therapeutic opportunities. Clinical heterogeneity in ALS and the lack of disease‐specific biomarkers have so far led to large‐sized clinical trials with long follow‐up needed to define clinical outcomes. In advanced ALS patients, there is presently limited scope to use imaging or invasive cerebrospinal fluid (CSF) collection as a source of disease biomarkers. The development of more patient‐friendly and accessible blood biomarker assays is hampered by analytical hurdles like the matrix effect of blood components. However, blood also provides the opportunity to identify disease‐specific adaptive changes of the stoichiometry and conformation of target proteins and the endogenous immunological response to low‐abundance brain peptides, such as neurofilaments (Nf). Among those biomarkers under investigation in ALS, the change in concentration before or after diagnosis of Nf has been shown to aid prognostication and to allow the a priori stratification of ALS patients into smaller sized and clinically more homogeneous cohorts, supporting more affordable clinical trials. Here, we discuss the technical hurdles affecting reproducible and sensitive biomarker measurement in blood. We also summarize the state of the art of non‐CSF biomarkers in the study of prognosis, disease progression, and treatment response. We will then address the potential as disease‐specific biomarkers of the newly discovered cryptic peptides which are formed down‐stream of TDP‐43 loss of function, the hallmark of ALS pathobiology. [ABSTRACT FROM AUTHOR]

Our solar system is filled with meteoric particles, or cosmic dust, which is either interplanetary or interstellar in origin. Interstellar dust (ISD) enters the heliosphere due to the relative motion of the sun and the interstellar flow. Interplanetary dust (IPD) comes primarily from asteroid collisions or comet sublimation, and comprises the bulk of material entering Earth's atmosphere. This study examines variations in ISD and the IPD flux at Earth using observations from three different satellite techniques. First are size-resolved in situ meteoroid detections by the Ulysses spacecraft, and second are in situ indirect dust observations by Wind. Third are measurements of meteoric smoke in the mesosphere by the Solar Occultation For Ice Experiment (SOFIE). Wind and Ulysses observations are sorted into the interstellar and interplanetary components. Wind ISD show the anticipated correlation to the 22-year solar magnetic cycle, and are consistent with model predictions of ISD. Because Wind does not discriminate particle size, the IPD measurements were interpreted using meteoric mass distributions from Ulysses observations and from different models. Wind observations during 2007–2020 indicate a total meteoric influx at Earth of 22 metric tons per day (t d−1), in reasonable agreement with long-term averages from SOFIE (25 t d−1) and Ulysses (32 t d−1). The SOFIE and Wind influx time series both show an unexpected correlation to the 22-year solar cycle. This relationship could be an artifact, or may indicate that IPD responds to changes in the solar magnetic field. [ABSTRACT FROM AUTHOR]

Advancing the understanding of lithum nickelate complexes, here we report a family of homoleptic organonickelate complexes obtained by reacting Ni(COD)2 and lithium aryl‐acetylides in the presence of the bidentate donor TMEDA. These compounds represent rare examples of low‐valent transition‐metals supported solely by organolithium ligands. Whilst the solid‐state structures indicate a hexagonal planar geometry around Ni0 with Ni−Li bonds, bonding analysis via QTAIM, NCI, NBO and ELI methods reveals that the Ni−Li interactions are repulsive in nature, characterising these complexes as tri‐coordinated. London dispersion forces between TMEDA and the organic substituents on nickel are found to play a crucial role in the stabilisation and thus isolation of these complexes. Preliminary reactivity studies demonstrate that the homoleptic lithium nickelates undergo stoichiometric cross‐coupling with PhI to give dinickel clusters containing both anionic acetylide and neutral alkyne ligands. [ABSTRACT FROM AUTHOR]

Plasmaspheric hiss waves are a dominant source of scattering for keV‐MeV radiation belt electrons within the plasmasphere. Previous simulation and modeling work concerning hiss waves has often incorporated them via particle‐based parameterizations (e.g., L‐shell). However, recent work has shown that not only is hiss wave power loosely dependent on L‐shell, but that proximity to the plasmapause may yield more accurate wave power distributions as it pertains to the modeling and scattering of electrons. This work serves to expand upon those previous studies by creating a low frequency (20–150 Hz) hiss wave model and incorporating a previously crafted high frequency (>150 Hz) hiss wave model based on plasmapause location, proximity to the plasmapause, and Kp activity level. Diffusion coefficients created using this method produced shorter lifetimes for electrons between ∼300 keV and 4 MeV than their L‐sorted counterparts. Furthermore, 3D‐simulations using and comparing the different hiss wave models (plasmapause sorting vs. L‐sorting) find that the plasmapause‐based approach yields more accurate results when compared to Van Allen Probe‐A observations. Plain Language Summary: Earth's radiation belts are composed of two highly dynamic regions consisting of very energetic charged particles (electrons and protons). These particles may become accelerated or scattered through a series of wave‐particle interactions. For this paper, we examined and tested various parametrizations of plasmapheric hiss waves to identify which parametrization scattered electrons more effectively and which best reproduced Van Allen Probe‐A observations. This study derived a new plasmapsheric hiss wave model, which incorporates the entire frequency range where hiss wave activity is observed (∼10–∼2,000 Hz). Furthermore, hiss wave activity was modeled with respect to plasmapause location instead of a purely L‐based parametrization. To test our model, we performed simulations with the versatile electron radiation belt‐3D code and compared our hiss wave model, a higher frequency (150–2,000 Hz) hiss wave model parametrized by plasmapause location, an L‐based plasmapause model, and a simulation with hiss wave activity excluded with the Van Allen Probe‐A electron (0.3–4.4 MeV) observations for the year 2013. Key Points: Low frequency (20–150 Hz) plasmaspheric hiss waves are modeled with respect to plasmapause location and distance from the plasmapauseThe plasmapause location‐based hiss wave modeling produces smaller lifetimes for ∼300 keV–4 MeV electrons3D simulations performed with this method yield more accurate results than L‐based hiss wave modeling [ABSTRACT FROM AUTHOR]

Background and purpose: This study was undertaken to determine the diagnostic and prognostic value of a panel of serum biomarkers and to correlate their concentrations with several clinical parameters in a large cohort of patients with amyotrophic lateral sclerosis (ALS). Methods: One hundred forty‐three consecutive patients with ALS and a control cohort consisting of 70 patients with other neurodegenerative disorders (DEG), 70 patients with ALS mimic disorders (ALSmd), and 45 healthy controls (HC) were included. Serum neurofilament light chain (NfL), ubiquitin carboxyl‐terminal hydrolase isozyme L1 (UCHL1), glial fibrillary acidic protein (GFAP), and total tau protein levels were measured using ultrasensitive single molecule array. Results: NfL correlated with disease progression rate (p < 0.001) and with the measures of upper motor neuron burden (p < 0.001). NfL was higher in the ALS patients with classic and pyramidal phenotype. GFAP was raised in ALS with cognitive–behavioral impairment compared with ALS with normal cognition. NfL displayed the best diagnostic performance in discriminating ALS from HC (area under the curve [AUC] = 0.990), DEG (AUC = 0.946), and ALSmd (AUC = 0.850). UCHL1 performed well in distinguishing ALS from HC (AUC = 0.761), whereas it was not helpful in differentiating ALS from DEG and ALSmd. In multivariate analysis, NfL (p < 0.001) and UCHL1 (p = 0.038) were independent prognostic factors. Survival analysis combining NfL and UCHL1 effectively stratified patients with lower NfL levels (p < 0.001). Conclusions: NfL is a useful biomarker for the diagnosis of ALS and the strongest predictor of survival. UCHL1 is an independent prognostic factor helpful in stratifying survival in patients with low NfL levels, likely to have slowly progressive disease. GFAP reflects extramotor involvement, namely cognitive impairment or frontotemporal dementia. [ABSTRACT FROM AUTHOR]

Objective: The BRAIN Study was established to assess the associations between self‐reported concussions and cognitive function among retired rugby players. Methods: Former elite‐level male rugby union players (50+ years) in England were recruited. Exposure to rugby‐related concussion was collected using the BRAIN‐Q tool. The primary outcome measure was the Preclinical Alzheimer Cognitive Composite (PACC). Linear regressions were conducted for the association between concussion and PACC score, adjusting for confounders. Results: A total of 146 participants were recruited. The mean (standard deviation) length of playing career was 15.8 (5.4) years. A total of 79.5% reported rugby‐related concussion(s). No association was found between concussion and PACC (β –0.03 [95% confidence interval (CI): –1.31, 0.26]). However, participants aged 80+ years reporting 3+ concussions had worse cognitive function than those without concussion (β –1.04 [95% CI: –1.62, –0.47]). Conclusions: Overall there was no association between concussion and cognitive function; however, a significant interaction with age revealed an association in older participants. [ABSTRACT FROM AUTHOR]

We present results, obtained by several instruments onboard NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, that show that the interaction region of the solar wind and the Martian upper atmosphere coincides with intense plasma wave activity. The turbulence region features nonlinear structures, identified as ion phase‐space holes and double layers, that emerge in the saturation phase of instabilities in the ion‐acoustic frequency range. One‐dimensional particle‐in‐cell simulations suggest that the waves and the nonlinear structures are very effective in coupling the flowing solar wind and the Martian plasma. Specifically, the simulations show that the magnetic field‐aligned component of the solar wind protons decelerates by about 20% in temporal and spatial scales of the orders of ∼100 ms and several kilometers, respectively. The results thus suggest that the waves may play an important role in the interaction region. Plain Language Summary: Unlike Earth, Mars does not have a global dipole magnetic field to protect its upper atmosphere against the solar wind. In the absence of this magnetic shield, charged particles originating from the Sun stream through the Martian upper atmosphere and strip away a small fraction of ions from its ionosphere. The relative importance of various mechanisms that lead to the transfer of energy and momentum from the flowing solar wind to the Martian ions is not fully understood. Here, we present data obtained by NASA's MAVEN spacecraft that shows that the interaction region of the solar wind and the Martian plasma environment features intense plasma waves. Simulations suggest that the electric fields of these waves can efficiently couple the charged particles from the solar wind with those from the Martian ionosphere and facilitate the exchange of energy and momentum. Key Points: Plasma waves in the frequency range of ion acoustic and lower‐hybrid frequencies are often observed along with accelerated planetary ionsThe turbulence region features ion phase‐space holes and double layers that likely evolve from waves in the ion acoustic frequency rangeWave structures are very effective in coupling the flowing solar wind and the Martian plasma [ABSTRACT FROM AUTHOR]

Background and purpose: The aim was to evaluate urinary neopterin, a marker of pro‐inflammatory state, as a potential biomarker of disease prognosis and progression in amyotrophic lateral sclerosis (ALS); and to compare its utility to urinary neurotrophin receptor p75 extracellular domain (p75ECD). Methods: This was an observational study including 21 healthy controls and 46 people with ALS, 29 of whom were sampled longitudinally. Neopterin and p75ECD were measured using enzyme‐linked immunoassays. Baseline and longitudinal changes in clinical measures, neopterin and urinary p75ECD were examined, and prognostic utility was explored by survival analysis. Results: At baseline, urinary neopterin was higher in ALS compared to controls (181.7 ± 78.9 μmol/mol creatinine vs. 120.4 ± 60.8 μmol/mol creatinine, p = 0.002, Welch's t test) and correlated with the Revised ALS Functional Rating Scale (r = −0.36, p = 0.01). Combining previously published urinary p75ECD results from 22 ALS patients with a further 24 ALS patients, baseline urinary p75ECD was also higher compared to healthy controls (6.0 ± 2.7 vs. 3.2 ± 1.0 ng/mg creatinine, p < 0.0001) and correlated with the Revised ALS Functional Rating Scale (r = −0.36, p = 0.01). Urinary neopterin and p75ECD correlated with each other at baseline (r = 0.38, p = 0.009). In longitudinal analysis, urinary neopterin increased on average (±SE) by 6.8 ± 1.1 µmol/mol creatinine per month (p < 0.0001) and p75ECD by 0.19 ± 0.02 ng/mg creatinine per month (p < 0.0001) from diagnosis in 29 ALS patients. Conclusion: Urinary neopterin holds promise as marker of disease progression in ALS and is worthy of future evaluation for its potential to predict response to anti‐inflammatory therapies. [ABSTRACT FROM AUTHOR]

Parker Solar Probe is the first mission to probe in situ the innermost heliosphere, revealing an exceptionally dynamic and structured outer solar corona. Its payload includes a search‐coil magnetometer (SCM) that measures up to three components of the fluctuating magnetic field between 3 Hz and 1 MHz. After more than 3 years of operation, the SCM has revealed a multitude of different wave phenomena in the solar wind. Here we present an overview of some of the discoveries made so far. These include oblique and sunward propagating whistler waves that are important for their interaction with energetic electrons, the first observation of the magnetic signature associated with escaping electrons during dust impacts, the first observation of the magnetic field component for slow extraordinary wave modes during type III radio burst events, and more. This study focuses on the major observations to date, including a description of the instrument and lessons learned. Plain Language Summary: The search‐coil magnetometer (SCM) search‐coil magnetometer on Parker Solar Probe is an instrument that measures fluctuations of the magnetic field in the solar wind. The instrument covers frequencies ranging from 3 Hz to 1 MHz. After 3 years of operation the SCM has revealed a wealth of different wave phenomena. Here, we describe some of the highlights. These include whistler waves that propagate oblique to the magnetic field, the first observation of the magnetic signature associated with the impact of dust particles, and the first observation of the magnetic signature of high‐frequency coherent waves that are associated with solar radio bursts. Key Points: We present an overview of 3 years of results from the search‐coil magnetometer (SCM) on Parker Solar ProbeThe SCM reveals the magnetic signature of dust impacts and of slow extraordinary waves associated with type III radio burstsThe SCM reveals in detail oblique whistlers and the radial evolution of turbulence at kinetic scales [ABSTRACT FROM AUTHOR]

How to manage human papillomavirus (HPV)‐positive women in cervical cancer screening remains debated. Our study compared different strategies to triage HPV positivity in a large cohort of women participating in a population HPV‐based screening program. Women were tested for HPV (Cobas 4800; Roche), and those positive were triaged with cytology; cytology‐positives were referred to colposcopy, while negatives were referred to 1‐year HPV retesting. All HPV‐positive women were also evaluated with p16/ki67 dual staining (Roche). All lesions found within 24 months of follow‐up were included in the analyses. Of the 70 146 women tested, 4757 (6.8%) were HPV‐positive. Of these, 1090 were cytology‐positive and were referred to colposcopy. Of the 2958 HPV‐positive/cytology‐negative women who presented at 1‐year retesting, 1752 (59.9%) still tested positive. Cumulatively, 532 CIN2+ (including 294 CIN3+) were found. The sensitivity of cytology, HPV16/18 and p16/ki67 as triage test for CIN3+ was 67.9%, 56.0% and 85.0%, respectively. The positive predictive value (PPV) for immediate colposcopy referral was 21.0%, 15.8% and 22.9%, respectively. Combining cytology with typing increased sensitivity to 83.9% and lowered PPV to 14.8%, while combining p16/ki67 and typing increased sensitivity to 91.1%, lowering the PPV to 15.9%. Women negative to p16/ki67 triage presented a cumulative 1‐year CIN3+ risk of about 1%. In conclusion, when triaging HPV positivity, p16/ki67 performed better than cytology with or without HPV16/18 genotyping. The strategies that included dual staining achieved sensitivity and low 1‐year risk for CIN3+ sufficiently high enough to permit considering extending the surveillance interval to 2 to 3 years for HPV‐positive/triage‐negative women. What's new? How to manage human papillomavirus (HPV)‐positive women in cervical cancer screening is still debated. In this large population‐based study, the authors evaluated the accuracy and performance of p16/ki67 dual staining, alone or in combination with HPV16/18 typing, as a triage test for HPV‐positive women in comparison with cytology. With or without HPV16/18 genotyping, p16/ki67 performed better than cytology in terms of both sensitivity and positive predictive value for CIN3+. The strategies that included dual staining achieved a high enough sensitivity with a low 1‐year risk of CIN3+ to potentially extend the current surveillance interval for HPV‐positive/triage‐negative women. [ABSTRACT FROM AUTHOR]

Copyright of Methods in Ecology & Evolution is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic‐regression analysis. The incidence of acute HDV per 1‐million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991–1999 to 44 years in the decade 2010–2019 (p <.001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p =.003) and that of HBsAg positive acute hepatitis tested for by IgM anti‐HDV linearly decreased from 50.1% to 34.1% (p <.001). People born abroad accounted for 24.6% of cases in 2004–2010 and 32.1% in 2011–2019. In the period 2010–2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4–12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15–10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM‐anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come. [ABSTRACT FROM AUTHOR]

Peridotites of Ulten Zone (Eastern Alps, N Italy) show a transition from coarse protogranular spinel lherzolites to fine‐grained amphibole + garnet peridotites, recorded by the crystallization of garnet coronas around spinel. Pyroxenite veins, transposed along the peridotite foliation, show a similar metamorphic evolution from coarse‐grained (garnet‐free) websterites to fine‐grained garnet websterites. In both peridotites and websterites, garnet previously exsolved from porphyroclastic high‐temperature pyroxenes and later crystallized along the foliation. This evolution has been interpreted to reflect cooling and pressure increase of websterites and host peridotites from spinel‐ to garnet‐facies conditions. Microstructures and crystallographic orientation data indicate that the re‐equilibration of garnet websterites in the garnet stability field occurred during deformation. Porphyroclastic pyroxenes have been interpreted to deform by dislocation glide and creep. In particular, TEM observations indicate the activation of the (100)[010] slip system in orthopyroxene. Core‐and‐mantle microstructures also suggest that dislocation creep was aided by subgrain rotation recrystallization, leading to the formation of neoblastic pyroxenes. These recrystallized grains deformed by diffusion‐accommodated grain boundary sliding, as indicated by the occurrence of quadruple junctions and straight, aligned grain boundaries. The transition from dislocation creep to diffusion creep in websterites was accompanied by the crystallization of garnet along foliation, which triggered the pinning of the recrystallized matrix and stabilized the fine‐grained microtexture for diffusion creep, promoting rheological weakening. Garnet websterites of Ulten Zone thus offer a unique opportunity to investigate the effects of reaction softening during the corner flow in the supra‐subduction lithospheric mantle induced by the descending slab. Plain Language Summary: When tectonic plates converge, one plate slides beneath the other plate descending into the Earth's mantle. During this process (the so‐called subduction), rocks forming the Earth's mantle, such as peridotites and pyroxenites, can be dragged to great depths and later transported back to the surface by a combination of two processes known as corner flow and exhumation. Rocks that experienced this journey are now exposed at the surface only in few mountain belts in the world (such as the European Alps) and represent natural laboratories to study the processes that occur at great depths in the Earth's mantle. In this study, we reconstruct the metamorphic and deformation evolution of pyroxenites of the Ulten Zone (Eastern Alps, N Italy). Minerals in pyroxenites deformed through different deformation processes, including dislocation creep and diffusion creep mechanisms. Our data indicate that minerals within pyroxenites record a transition in the deformation mechanism from dislocation to diffusion creep. This switch of the deformation mechanism was responsible for a significant rheological weakening of pyroxenites, suggesting that pyroxenites can play a major role in the processes that control the deformational behavior of the Earth's mantle. Key Points: In websterites of Ulten zone, pyroxenes switch from dislocation to diffusion‐creep‐dominated deformationThe transition in deformation mechanism took place during the prograde re‐equilibration of websterites in the garnet stability fieldThis results in the rheological weakening of websterites during the corner flow of the lithospheric mantle induced by the slab subduction [ABSTRACT FROM AUTHOR]

Electrostatic solitary waves (ESWs) are a type of nonlinear time‐domain plasma structure (TDS) generally defined by bipolar electric fields and propagation parallel to the local magnetic field. Formation mechanisms for TDSs in the magnetosphere have been studied extensively and are associated with plasma boundary layers and the braking of bursty bulk flows (BBFs). However, the rapid timescales over which these TDSs occur (<2 ms) make them infeasible to count by eye over large time periods. Furthermore, high‐cadence data are not always available. The Solitary Wave Detector (SWD) on NASA's Magnetospheric Multiscale (MMS) mission quantifies the occurrence and amplitude of TDS throughout the constellation's orbit; analysis of burst (65 kS/s) parallel electric field data indicates that the SWD captures approximately 60% of all bipolar TDS encountered in the tail region, enabling large‐scale examination of their occurrence. Maps of TDS occurrence rates during several years of the MMS mission were generated from SWD data, showing enhanced TDS density in the tail region between 6 and 9 Re; enhance occurrence in or near shocks; and an unexpected enhancement in the dawn side of the tail and in the radiation belt. Key Points: The MMS Solitary Wave Detector records time‐domain structures in Earth's magnetosphereSWD maps highlight regions like the Van Allen belts and the bursty bulk flow braking regionThe SWD shows intriguing nonlinear activity in the shocks, magnetotail, flank, and dawn‐side outer radiation belt [ABSTRACT FROM AUTHOR]

The Brønsted acidity of the perfluorinated trialkoxysilanol {(F3C)3CO}3SiOH is more than 13 orders of magnitude higher than that of orthosilicic acid, Si(OH)4, and even more for most previously known silanols. It is easily deprotonated by simple amines and pyridines to give the conjugate silanolates [OSi{OC(CF3)3}3]−, which possess extremely short Si−O bonds, comparable to those of silanones. [ABSTRACT FROM AUTHOR]

In this paper we study electrostatic waves with time‐dependent frequency features in the terrestrial foreshock. These short (0.1–0.3 s) duration waves are characterized by a significant frequency drift where the peak wave power shifts from a few hundred Hz to 2–4,000 Hz in a few hundred milliseconds. Based on the electric field data from the Magnetospheric Multiscale Mission (MMS) we have identified 46 of these wave packets. Using four spacecraft timing approach we find that these waves have a propagation direction pointing upstream. However, their plasma frame velocity is less than the solar wind speed, therefore they are eventually convected downstream toward the bow shock. We use the double‐probes of MMS and present an interferometric analysis, which allows us to obtain the dispersion relation of these waves and directly compare them to theoretical ones. We show that the measured dispersion relations are in good agreement with Doppler shifted ion acoustic waves and discuss potential mechanisms related to impulsive reflected ions that may allow the growth of these waves and cause time‐dependent frequency features. Key Points: We analyze electrostatic waves with time‐dependent frequency features in the foreshock using the double‐probes of Magnetospheric Multiscale MissionThe measured wavenumber‐frequency plots are in excellent agreement with ion acoustic wave dispersion relationsWe discuss potential mechanisms, which may lead to the time‐dependent frequency features of the waves [ABSTRACT FROM AUTHOR]

Sudden olfactory loss in the absence of concurrent nasal congestion is now a well‐recognized symptom of COVID‐19. We examined olfaction using standardized objective tests of odour detection, identification and hedonics collected from asymptomatic university students before and as SARS‐CoV‐2 emerged locally. Olfactory performance of students who were tested when the virus is known to be endemic (n = 22) was compared to students tested in the month prior to viral circulation (n = 25), a normative sample assessed during the previous 4 years (n = 272) and those tested in prior years during the same time period. Analyses showed significantly reduced odour detection for the virus exposed cohort compared to students tested before (t = 2.60; P =.01; d = 0.77; CI 0.17, 1.36) and to the normative sample (D = 0.38; P =.005). Odour identification scores were similar, but the exposed cohort rated odours as less unpleasant (P <.001, CLES = 0.77). Hyposmia increased 4.4‐fold for students tested 2 weeks before school closure (N = 22) and increased 13.6‐fold for students tested in the final week (N = 11). While the unavailability of COVID‐19 testing is a limitation, this naturalistic study demonstrates week‐by‐week increase in hyposmia in asymptomatic students as a virus was circulating on campus, consistent with increasing airborne viral loads. The specific hedonic deficit in unpleasantness appraisal suggests a deficit in the TAAR olfactory receptor class, which conveys the social salience of odours. Assessment of odour detection and hedonic ratings may aid in early detection of SARS‐CoV‐2 exposure in asymptomatic and pre‐symptomatic persons. [ABSTRACT FROM AUTHOR]

Objective: To appraise the utility as biomarkers of blood antibodies and immune complexes to neurofilaments and dipeptide repeat proteins, the products of translation of the most common genetic mutation in amyotrophic lateral sclerosis (ALS). Methods: Antibodies and immune complexes against neurofilament light, medium, heavy chains as well as poly‐(GP)‐(GR) dipeptide repeats were measured in blood samples from the ALS Biomarkers (n = 107) and the phenotype–genotype biomarker (n = 129) studies and in 140 healthy controls. Target analyte levels were studied longitudinally in 37 ALS cases. Participants were stratified according to the rate of disease progression estimated before and after baseline and C9orf72 genetic status. Survival and longitudinal analyses were undertaken with reference to matched neurofilament protein expression. Results: Compared to healthy controls, total neurofilament proteins and antibodies, neurofilament light immune complexes (p < 0.0001), and neurofilament heavy antibodies (p = 0.0061) were significantly elevated in ALS, patients with faster progressing disease (p < 0.0001) and in ALS cases with a C9orf72 mutation (p < 0.0003). Blood neurofilament light protein discriminated better ALS from healthy controls (AUC: 0.92; p < 0.0001) and faster from slower progressing ALS (AUC: 0.86; p < 0.0001) compared to heavy‐chain antibodies and light‐chain immune complexes (AUC: 0.79; p < 0.0001 and AUC: 0.74; p < 0.0001). Lower neurofilament heavy antibodies were associated with longer survival (Log‐rank Chi‐square: 7.39; p = 0.0065). Increasing levels of antibodies and immune complexes between time points were observed in faster progressing ALS. Conclusions: We report a distinctive humoral response characterized by raising antibodies against neurofilaments and dipeptide repeats in faster progressing and C9orf72 genetic mutation carriers ALS patients. We confirm the significance of plasma neurofilament proteins in the clinical stratification of ALS. [ABSTRACT FROM AUTHOR]

The available magnetic field data from the terrestrial magnetosphere, solar wind and planetary magnetospheres exceeds over 106 hours. Identifying plasma waves in these large data sets is a time consuming and tedious process. In this Paper, we propose a solution to this problem. We demonstrate how self‐organizing maps (SOMs) can be used for rapid data reduction and identification of plasma waves in large data sets. We use 72,000 fluxgate and 110,000 search coil magnetic field power spectra from the Magnetospheric Multiscale Mission (MMS1) and show how the SOM sorts the power spectra into groups based on their shape. Organizing the data in this way makes it very straightforward to identify power spectra with similar properties and therefore this technique greatly reduces the need for manual inspection of the data. We suggest that SOMs offer a time effective and robust technique, which can significantly accelerate the processing of magnetic field data and discovery of new wave forms. Key Points: We develop a robust method to classify large data sets of power spectra of magnetic fieldThe technique significantly reduces the need for time consuming manual inspection of the data and allows the discovery of new wave formsThe classification technique can be used to categorize plasma waves based on frequency, amplitude and bandwidth [ABSTRACT FROM AUTHOR]

Plasma sheet electron precipitation into the diffuse aurora is critical for magnetosphere‐ionosphere coupling. Recent studies have shown that electron phase space holes can pitch‐angle scatter electrons and may produce plasma sheet electron precipitation. These studies have assumed identical electron hole parameters to estimate electron scattering rates (Vasko et al., 2018, https://doi.org/10.1063/1.5039687). In this study, we have re‐evaluated the efficiency of this scattering by incorporating realistic electron hole properties from direct spacecraft observations into computing electron diffusion rates and lifetimes. The most important electron hole properties in this evaluation are their distributions in velocity and spatial scale and electric field root‐mean‐square intensity (Ew). Using direct measurements of electron holes during a plasma injection event observed by the Van Allen Probe at R∼6RE, we find that when Ew≥4 mV/m electron lifetimes can drop below 1 h and are mostly within strong diffusion limits at energies below ∼10 keV. During an injection observed by the THEMIS spacecraft at R∼12RE, electron holes with even typical intensities (Ew≥1 mV/m) can deplete low‐energy (

Dust impacts on spacecraft are commonly detected by antenna instruments as transient voltage perturbations. The signal waveform is generated by the interaction between the impact‐generated plasma cloud and the elements of the antenna–spacecraft system. A general electrostatic model is presented that includes the two key elements of the interaction, namely the charge recollected from the impact plasma by the spacecraft and the fraction electrons and cations that escape to infinity. The clouds of escaping electrons and cations generate induced signals, and their vastly different escape speeds are responsible for the characteristic shape of the waveforms. The induced signals are modeled numerically for the geometry of the system and the location of the impact. The model employs a Maxwell capacitance matrix to keep track of the mutual interaction between the elements of system. A new reduced‐size model spacecraft is constructed for laboratory measurements using the dust accelerator facility. The model spacecraft is equipped with four antennas: two operating in a monopole mode, and one pair configured as a dipole. Submicron‐sized iron dust particles accelerated to >20 km/s are used for test measurements, where the waveforms of each antenna are recorded. The electrostatic model provides a remarkably good fit to the data using only a handful of physical fitting parameters, such as the escape speeds of electrons and cations. The presented general model provides the framework for analyzing antenna waveforms and is applicable for a range of space missions investigating the distribution of dust particles in relevant environments. Key Points: Analysis and interpretation of dust impact signals are improved by a new electrostatic model based on recollected and induced charge effectsA laboratory model is constructed to verify the validity of presented model and measure the basic properties of dust impact plasma plumesThe electrostatic model provides the framework for interpreting antenna waveforms and determining the parameters of impacting dust particles [ABSTRACT FROM AUTHOR]

Extreme precipitation (EP) events are life‐threatening phenomena that are expected to continue to increase because of ongoing climate change. In the past decade, these events have been caused by important and well‐documented variations in large‐scale atmospheric circulation. Identifying the trends, dynamics, and related causes of EP could help in recognizing geographical areas that are at great risk and reducing their adverse impacts, particularly on a relatively small area such as the Italian peninsula. The relationships between large‐scale circulation types (CTs) and EP were investigated using a long time‐series (1979–2015) of meteorological data recorded by 46 weather stations in Italy. EP was defined as the number of days with accumulated precipitation above the 90th percentile (R90p). The seasonal trends of R90p were not homogeneous and showed significant increases primarily in winter and spring. Only a few CTs were significantly related to R90p, and this relationship was strongly dependent on latitude, orographic exposure, and season. Heterogeneous seasonal trends for daily CT occurrences were also observed. 'Cyclonic' CTs grouped together showed significant increasing trends in all seasons, whereas 'Anticyclonic' ones showed a generalized decreasing trend, explaining, only partially, the increase of R90p observed in some stations. Meanwhile, the R90p trends seem to be more influenced by the variations in the internal characteristics of CTs (i.e., the variation of some meteorological parameters that characterize them) observed over the past few decades than by changes in CT frequencies but still with high heterogeneity in Italy. The results of this and other similar studies can provide useful support for the implementation of mitigation and adaptation strategies to minimize the impacts of severe weather, particularly in complex areas such as the Mediterranean basin. [ABSTRACT FROM AUTHOR]

Observations of the plasma environment outside of the Earth's magnetosphere by the Magnetospheric Multiscale Mission Hot Plasma Composition Analyzers (MMS‐HPCAs) allow density measurements of geocoronal hydrogen pickup ions (PUIs). A study of this environment from December 4, 2019 to December 6, 2019, part of a single orbital period of the MMS spacecraft, revealed an inverse square dependence on PUI density. This dependence corresponds well with an inverse‐cube dependence on the neutral hydrogen density within the geocorona. Plain Language Summary: Measuring pickup ions produced from the Earth's geocorona provide an in‐situ analysis of their geocentric density dependence. These measurements also provide a model‐dependent evaluation of the neutral geocorona's expanse and geocentric dependence, which is part of the Earth's extended atmosphere, also known as the exosphere. Key Points: Pickup ions (PUIs) produced from the hydrogen exosphere are observable with near‐Earth plasma instrumentsPickup ions are distinguishable from solar wind ions through their respective velocity distributionsGeocoronal PUI density decreases with geocentric radius and corresponds to an inverse radius cube neutral dependence [ABSTRACT FROM AUTHOR]

Summary: We investigated the current role of interferon‐alpha (IFNα) in hairy cell leukaemia (HCL) in a retrospective analysis of patients with HCL. A cohort of 74 patients with HCL was divided in to three groups: (A) patients aged >65 years with first‐line treatment; (B) patients with comorbidities with first‐line treatment; (C) patients who were purine analogues resistant. In total, 94% achieved a response, with a complete response rate of 24%. After a median (range) follow‐up of 60 (7–236) months, 55 patients (78%) are still responding. The 5‐year progression‐free survival was 95%, 68%, and 96% in groups A, B and C respectively. A proportion of patients were monitored through their B‐Raf proto‐oncogene, serine/threonine kinase (BRAF)‐V600E status. IFNα remains a possible option in select patients with HCL, where minimal residual disease negativity is achievable. [ABSTRACT FROM AUTHOR]

A sequence of discrete solar wind structures within the sheath region of an interplanetary coronal mass ejection on November 6, 2015, caused a series of compressions and releases of the dayside magnetosphere. Each compression resulted in a brief adiabatic enhancement of ions (electrons) driving bursts of electromagnetic ion cyclotron (EMIC; whistler mode chorus) wave growth across the dayside magnetosphere. Fine-structured rising tones were observed in the EMIC wave bursts, resulting in nonlinear scattering of relativistic electrons in the outer radiation belt. Multipoint observations allow us to study the spatial structure and evolution of these sheath structures as they propagate Earthward from L1 as well as the spatio-temporal characteristics of the magnetospheric response. This event highlights the importance of fine-scale solar wind structure, in particular within complex sheath regions, in driving dayside phenomena within the inner magnetosphere. Plain Language Summary On November 6, 2015, a sequence of abrupt changes in Earth's magnetic field and the associated conditions in the solar wind were observed. Multispacecraft observations allow us to study both the spatial structure and evolution of the solar wind structures that impacted the Earth, as well as the response of Earth's magnetic field and particles trapped within it. The fine-scale structures observed in the solar wind are demonstrated to produce distinct magnetospheric particle distributions and wave excitation. This event highlights the importance of fine-scale solar wind structure in driving magnetospheric phenomena. [ABSTRACT FROM AUTHOR]