Investigating global scale dust storms on Mars with ASPERA-3

<p>2007 and 2018 saw global scale dust storms engulfing the entirety of Mars, lasting several months. These events have a profound impact across Mars, with dust reaching altitudes up to 80 km and global temperatures rising by up to 40 K. This significant change in the Martian atmosphere may lead to changes in the ionosphere and above. During the 2007 storm, it was seen in Mars Express (MEx) radar data that ionisation created in the lower atmosphere is observed at higher altitudes, with an altitude dependent enhancement in plasma density over crustal magnetic fields (Venkateswara <em>et al.,</em> 2019). It may be likely that during these dust events, atmosphere loss is enhanced.</p> <p>MEx launched in 2003, became operational in 2004 and is still collecting data today. Onboard are seven scientific instruments which are answering questions about the atmosphere, surface and geology at Mars, whilst looking for signs of water and life. With a period of seven hours, MEx provides extensive coverage of data collection. One of the seven instruments, the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) has produced a long time-base of plasma measurements from as low as 250 km. ASPERA-3 aims to investigate the interaction of the solar wind with the Martian atmosphere, looking at the mechanisms that may enhance the loss of gases from Mars.</p> <p>ASPERA-3 will be used to investigate the effects the 2007 and 2018 global dust storms had on the plasma environment by comparing data before, during, and after the event.  Of particular interest are plasma measurements over radial magnetic fields from crustal anomalies, where transport of charged particles is guided out of the atmosphere.  The before, during, and after effects will shed light on to the influence dust storms have on the escaping plasma measured by ASPERA-3 and how dust changes the local plasma escape directly from the atmosphere. Our initial study focuses on data from the electron spectrometer (ELS) where we investigate how the energy distribution and peak energy value varies in altitude above the Martian surface. We will also relate our observations back down to the Martian surface, where we will investigate how surface features may influence the atmosphere and ionosphere above them. This will focus on the southern hemispheric crustal fields and geological features, such as impact basins and volcanoes.</p>

Plasma biomarkers of Alzheimer’s disease improve prediction of cognitive decline in cognitively unimpaired elderly populations

Plasma biomarkers of amyloid, tau, and neurodegeneration (ATN) need to be characterized in cognitively unimpaired (CU) elderly individuals. We therefore tested if plasma measurements of amyloid-β (Aβ)42/40, phospho-tau217 (P-tau217), and neurofilament light (NfL) together predict clinical deterioration in 435 CU individuals followed for an average of 4.8 ± 1.7 years in the BioFINDER study. A combination of all three plasma biomarkers and basic demographics best predicted change in cognition (Pre-Alzheimer’s Clinical Composite; R2 = 0.14, 95% CI [0.12–0.17]; P < 0.0001) and subsequent AD dementia (AUC = 0.82, 95% CI [0.77–0.91], P < 0.0001). In a simulated clinical trial, a screening algorithm combining all three plasma biomarkers would reduce the required sample size by 70% (95% CI [54–81]; P < 0.001) with cognition as trial endpoint, and by 63% (95% CI [53–70], P < 0.001) with subsequent AD dementia as trial endpoint. Plasma ATN biomarkers show usefulness in cognitively unimpaired populations and could make large clinical trials more feasible and cost-effective.

EXPRESS: Measurement of vitamin D in dried blood spots stored under different temperature conditions

Background: As part of the Survey of Health, Ageing and Retirement in Europe (SHARE) study, dried blood spot (DBS) samples were obtained for measurement of potential biological biomarkers, among those vitamin D. Unfortunately, no studies describe the impact of high temperatures on DBS samples and vitamin D measurements. Materials and methods: Capillary samples were collected on DBS cards from 40 outpatients (median age 78 years) along with venous blood samples. To mimic the different environmental and temporal challenges during collection and shipment until final storage in the SHARE study, DBS cards were stored at different temperatures, at time span and with/without freeze-thaw. Vitamin D concentrations in venous plasma samples was measured by conventional immunoassay (on Architect i2000SR), while vitamin D concentrations in DBS samples were measured using LC-MS/MS with a well-described extraction method and with relevant calibration and comparison with a reference method. Results: Vitamin D measured in DBS samples did not differ significantly from venous plasma measurements under the different storage conditions tested. The optimal vitamin D correlation between the two matrices were by storage at either 21 °C or 35 °C for four days (r = 0.9060 and 0.9026, resp.). Freeze-thaw of the DBS samples did not have any significant effect. Conclusion: We find that vitamin D measured in DBS samples do not differ significantly from venous plasma measurements despite storage at different temperatures and freeze-thaw, which enables the use of DBS in multicenter studies taking place under alternating temperature conditions.

Case Report: Inflammation and Endothelial Injury Profiling of COVID-19 Pediatric Multisystem Inflammatory Syndrome (MIS-C)

Introduction: COVID-19 is associated with a novel multi-system inflammatory syndrome that shares some characteristics with Kawasaki's Disease. The syndrome manifestation is delayed relative to COVID-19 onset, with a spectrum of clinical severity. Clinical signs may include persistent fever, gastrointestinal symptoms, cardiac inflammation and/or shock.Case Presentation: We measured 59 inflammatory and endothelial injury plasma analytes in an adolescent girl that presented with malaise, fever, cough, strawberry tongue and jaundice. Her COVID-19 status was positive with detection of 2 SARS-CoV-2 viral genes using polymerase chain reaction. She was treated with intravenous immunoglobulin prior to blood draw, but our plasma measurements suggested a unique analyte expression pattern associated with inflammation, endothelial injury and microvascular glycocalyx degradation.Conclusions: COVID-19 is associated with a multi-system inflammatory syndrome and a unique inflammatory and endothelial injury signature.Summary: Analyte markers of inflammation and endothelial cell injury might serve as putative biomarkers and/or be investigated further as potential therapeutic targets.

A charging model for the Rosetta spacecraft

&lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;p&gt;Context. The electrostatic potential of a spacecraft, V&lt;sub&gt;S&lt;/sub&gt;, is important for the capabilities of in situ plasma measurements. Rosetta has been found to be negatively charged during most of the comet mission and even more so in denser plasmas.&lt;br&gt;Aims. Our goal is to investigate how the negative V&lt;sub&gt;S&lt;/sub&gt; correlates with electron density and temperature and to understand the physics of the observed correlation.&lt;/p&gt; &lt;p&gt;Methods. We applied full mission comparative statistics of V&lt;sub&gt;S&lt;/sub&gt;, electron temperature, and electron density to establish V&lt;sub&gt;S&lt;/sub&gt; dependence on cold and warm plasma density and electron temperature. We also used Spacecraft-Plasma Interaction System (SPIS) simulations and an analytical vacuum model to investigate if positively biased elements covering a fraction of the solar array surface can explain the observed correlations.&lt;/p&gt; &lt;p&gt;Results. Here, the V&lt;sub&gt;S&lt;/sub&gt; was found to depend more on electron density, particularly with regard to the cold part of the electrons, and less on electron temperature than was expected for the high flux of thermal (cometary) ionospheric electrons. This behaviour was reproduced by an analytical model which is consistent with numerical simulations.&lt;br&gt;Conclusions. Rosetta is negatively driven mainly by positively biased elements on the borders of the front side of the solar panels as these can efficiently collect cold plasma electrons. Biased elements distributed elsewhere on the front side of the panels are less efficient at collecting electrons apart from locally produced electrons (photoelectrons). To avoid significant charging, future spacecraft may minimise the area of exposed bias conductors or use a positive ground power system.&lt;/p&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt;

The effect of stream interaction regions on CME structures: observations in longitudinal conjunction at Mercury and 1 AU

&lt;p&gt;We present a study of two CMEs observed at Mercury and 1 AU by spacecraft in longitudinal conjunction. Of the two CMEs, one propagated relatively self-similarly, while the other one underwent significant changes in its properties, making them excellent case studies to investigate the following question: what causes the drastic alterations observed in some CMEs during propagation, while other CMEs remain relatively unchanged? Answering this question will also help us better understand the potential impact of CMEs on the near-Earth environment.&amp;#160;&lt;/p&gt;&lt;p&gt;In this work we focus on the presence or absence of large-scale corotating structures in the propagation space between Mercury and 1 AU, that have been shown in the past to influence &amp;#160;the orientation&amp;#160; of&amp;#160; CME&amp;#160; magnetic&amp;#160; structures&amp;#160; and&amp;#160; the&amp;#160; properties&amp;#160; of&amp;#160; CME&amp;#160; sheaths. At both locations, we determine the CME flux rope orientation and characteristics using different fitting and classification methods. Our analysis is complemented by solar wind plasma measurements near 1 AU, by estimates of the size evolution of the sheaths and magnetic ejecta with heliocentric distance, and by the identification of solar wind structures in the CME propagation space based on in situ data, remote-sensing observations, and numerical simulations of the solar wind conditions in the inner heliosphere.&lt;/p&gt;&lt;p&gt;Results indicate that the changes observed in one CME were likely caused by a stream interaction region, while the CME exhibiting little change did not interact with any large-scale structure between Mercury and 1 AU. This work provides end-member examples of CME propagation in the inner heliosphere, exemplifying how interactions&amp;#160; with&amp;#160; corotating&amp;#160; structures&amp;#160; in&amp;#160; the&amp;#160; solar&amp;#160; wind&amp;#160; can&amp;#160; induce&amp;#160; essential&amp;#160; changes&amp;#160; in&amp;#160; CME structures. Our findings provide new fundamental insights on the propagation and evolution of CMEs, and can help lay the foundation for improved predictions of CME properties at 1 AU.&lt;/p&gt;

Plasma and Magnetic Field Turbulence in the Earth’s Magnetosheath at Ion Scales

Crossing the Earth’s bow shock is known to crucially affect solar wind plasma including changes in turbulent cascade. The present review summarizes results of more than 15 years of experimental exploration into magnetosheath turbulence. Great contributions to understanding turbulence development inside the magnetosheath was made by means of recent multi-spacecraft missions. We introduce the main results provided by them together with first observations of the turbulent cascade based on direct plasma measurements by the Spektr-R spacecraft in the magnetosheath. Recent results on solar wind effects on turbulence in the magnetosheath are also discussed.