Solar Probe Plus (SPP) will be the first spacecraft to fly into the low solar corona. SPP’s main science goal is to determine the structure and dynamics of the Sun’s coronal magnetic field, ...understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Understanding these fundamental phenomena has been a top-priority science goal for over five decades, dating back to the 1958 Simpson Committee Report. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The mission design and the technology and engineering developments enable SPP to meet its science objectives to: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles. The SPP mission was confirmed in March 2014 and is under development as a part of NASA’s Living with a Star (LWS) Program. SPP is scheduled for launch in mid-2018, and will perform 24 orbits over a 7-year nominal mission duration. Seven Venus gravity assists gradually reduce SPP’s perihelion from 35 solar radii (
R
S
) for the first orbit to
<
10
R
S
for the final three orbits. In this paper we present the science, mission concept and the baseline vehicle for SPP, and examine how the mission will address the key science questions
Clinical manifestations of COVID-19 caused by the new coronavirus SARS-CoV-2 are associated with age
. Adults develop respiratory symptoms, which can progress to acute respiratory distress syndrome ...(ARDS) in the most severe form, while children are largely spared from respiratory illness but can develop a life-threatening multisystem inflammatory syndrome (MIS-C)
. Here, we show distinct antibody responses in children and adults after SARS-CoV-2 infection. Adult COVID-19 cohorts had anti-spike (S) IgG, IgM and IgA antibodies, as well as anti-nucleocapsid (N) IgG antibody, while children with and without MIS-C had reduced breadth of anti-SARS-CoV-2-specific antibodies, predominantly generating IgG antibodies specific for the S protein but not the N protein. Moreover, children with and without MIS-C had reduced neutralizing activity as compared to both adult COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children independent of whether they develop MIS-C, with implications for developing age-targeted strategies for testing and protecting the population.
Human T cells coordinate adaptive immunity in diverse anatomic compartments through production of cytokines and effector molecules, but it is unclear how tissue site influences T cell persistence and ...function. Here, we use single cell RNA-sequencing (scRNA-seq) to define the heterogeneity of human T cells isolated from lungs, lymph nodes, bone marrow and blood, and their functional responses following stimulation. Through analysis of >50,000 resting and activated T cells, we reveal tissue T cell signatures in mucosal and lymphoid sites, and lineage-specific activation states across all sites including distinct effector states for CD8
T cells and an interferon-response state for CD4
T cells. Comparing scRNA-seq profiles of tumor-associated T cells to our dataset reveals predominant activated CD8
compared to CD4
T cell states within multiple tumor types. Our results therefore establish a high dimensional reference map of human T cell activation in health for analyzing T cells in disease.
The structure of magnetic flux ropes injected into the solar wind during reconnection in the coronal atmosphere is explored with particle-in-cell simulations and compared with in situ measurements of ...magnetic “switchbacks” from the Parker Solar Probe. We suggest that multi-x-line reconnection between open and closed flux in the corona injects flux ropes into the solar wind and that these flux ropes convect outward over long distances before eroding due to reconnection. Simulations that explore the magnetic structure of flux ropes in the solar wind reproduce the following key features of the switchback observations: a rapid rotation of the radial magnetic field into the transverse direction, which is a consequence of reconnection with a strong guide field; and the potential to reverse the radial field component. The potential implication of the injection of large numbers of flux ropes in the coronal atmosphere for understanding the generation of the solar wind is discussed.
The global COVID-19 pandemic has radically changed the way health care is delivered in many countries around the world. Evidence on the experience of those receiving or providing maternity care is ...important to guide practice through this challenging time.
A cross-sectional study was conducted in Australia. Five key stakeholder cohorts were included to explore and compare the experiences of those receiving or providing care during the COVID-19 pandemic. Women, their partners, midwives, medical practitioners and midwifery students who had received or provided maternity care from March 2020 onwards in Australia were recruited via social media and invited to participate in an online survey released between 13th May and 24th June 2020; a total of 3701 completed responses were received.
While anxiety related to COVID-19 was high among all five cohorts, there were statistically significant differences between the responses from each cohort for most survey items. Women were more likely to indicate concern about their own and family's health and safety in relation to COVID-19 whereas midwives, doctors and midwifery students were more likely to be concerned about occupational exposure to COVID-19 through working in a health setting than those receiving care through attending these environments. Midwifery students and women's partners were more likely to respond that they felt isolated because of the changes to the way care was provided. Despite concerns about care received or provided not meeting expectations, most respondents were satisfied with the quality of care provided, although midwives and midwifery students were less likely to agree.
This paper provides a unique exploration and comparison of experiences of receiving and providing maternity care during the COVID-19 pandemic in Australia. Findings are useful to support further service changes and future service redesign. New evidence provided offers unique insight into key stakeholders' experiences of the rapid changes to health services.
Immune response dynamics in coronavirus disease 2019 (COVID-19) and their severe manifestations have largely been studied in circulation. Here, we examined the relationship between immune processes ...in the respiratory tract and circulation through longitudinal phenotypic, transcriptomic, and cytokine profiling of paired airway and blood samples from patients with severe COVID-19 relative to heathy controls. In COVID-19 airways, T cells exhibited activated, tissue-resident, and protective profiles; higher T cell frequencies correlated with survival and younger age. Myeloid cells in COVID-19 airways featured hyperinflammatory signatures, and higher frequencies of these cells correlated with mortality and older age. In COVID-19 blood, aberrant CD163+ monocytes predominated over conventional monocytes, and were found in corresponding airway samples and in damaged alveoli. High levels of myeloid chemoattractants in airways suggest recruitment of these cells through a CCL2-CCR2 chemokine axis. Our findings provide insights into immune processes driving COVID-19 lung pathology with therapeutic implications for targeting inflammation in the respiratory tract.
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•Airways show localized immune responses correlating to age and outcome in COVID-19•Airway T cells are activated and resident, while myeloid cells are hyperinflammatory•Aberrant CD163hi and HLA-DRlo monocytes predominate in COVID-19 blood•Monocytes infiltrate airways and lung alveoli potentially through a CCL2-CCR2 axis
Through longitudinal profiling of paired airways and blood from patients with severe COVID-19, Szabo et al. reveal airway immune responses that correlate with age and outcome. They further identify coordinate roles for T and myeloid cells in the respiratory tract and circulation in perpetuating lung pathology and disease pathogenesis.
Superantigens (SAgs) are potent exotoxins secreted by Staphylococcus aureus and Streptococcus pyogenes. They target a large fraction of T cell pools to set in motion a "cytokine storm" with severe ...and sometimes life-threatening consequences typically encountered in toxic shock syndrome (TSS). Given the rapidity with which TSS develops, designing timely and truly targeted therapies for this syndrome requires identification of key mediators of the cytokine storm's initial wave. Equally important, early host responses to SAgs can be accompanied or followed by a state of immunosuppression, which in turn jeopardizes the host's ability to combat and clear infections. Unlike in mouse models, the mechanisms underlying SAg-associated immunosuppression in humans are ill-defined. In this work, we have identified a population of innate-like T cells, called mucosa-associated invariant T (MAIT) cells, as the most powerful source of pro-inflammatory cytokines after exposure to SAgs. We have utilized primary human peripheral blood and hepatic mononuclear cells, mouse MAIT hybridoma lines, HLA-DR4-transgenic mice, MAIThighHLA-DR4+ bone marrow chimeras, and humanized NOD-scid IL-2Rγnull mice to demonstrate for the first time that: i) mouse and human MAIT cells are hyperresponsive to SAgs, typified by staphylococcal enterotoxin B (SEB); ii) the human MAIT cell response to SEB is rapid and far greater in magnitude than that launched by unfractionated conventional T, invariant natural killer T (iNKT) or γδ T cells, and is characterized by production of interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-2, but not IL-17A; iii) high-affinity MHC class II interaction with SAgs, but not MHC-related protein 1 (MR1) participation, is required for MAIT cell activation; iv) MAIT cell responses to SEB can occur in a T cell receptor (TCR) Vβ-specific manner but are largely contributed by IL-12 and IL-18; v) as MAIT cells are primed by SAgs, they also begin to develop a molecular signature consistent with exhaustion and failure to participate in antimicrobial defense. Accordingly, they upregulate lymphocyte-activation gene 3 (LAG-3), T cell immunoglobulin and mucin-3 (TIM-3), and/or programmed cell death-1 (PD-1), and acquire an anergic phenotype that interferes with their cognate function against Klebsiella pneumoniae and Escherichia coli; vi) MAIT cell hyperactivation and anergy co-utilize a signaling pathway that is governed by p38 and MEK1/2. Collectively, our findings demonstrate a pathogenic, rather than protective, role for MAIT cells during infection. Furthermore, we propose a novel mechanism of SAg-associated immunosuppression in humans. MAIT cells may therefore provide an attractive therapeutic target for the management of both early and late phases of severe SAg-mediated illnesses.
Vaccination against COVID-19 is a key global public health strategy. Health professionals including midwives and doctors support and influence vaccination uptake by childbearing women. There is ...currently no evidence regarding the COVID-19 vaccination perceptions and intentions of those who receive or provide maternity care in Australia. The aim of this study was to address this gap in knowledge and explore the perceptions and intentions regarding COVID-19 vaccination from consumers and providers of maternity care in Australia. A national cross-sectional online study conducted in early 2021 in Australia, a country that has had a very low number of COVID-19 cases and deaths. Recruitment was undertaken through parenting and health professional social media sites and professional college distribution lists. A total of 853 completed responses, from women (n = 326), maternity care providers including doctors (n = 58), midwives (n = 391) and midwifery students (n = 78). Personal intention to be vaccinated ranged from 48-89% with doctors most likely and women least likely. Doctors and midwifery students were significantly more likely to recommend the vaccine to pregnant women in their care than midwives (p<0.001). Fewer doctors (2%) felt that women should wait until breastfeeding had concluded before being vaccinated compared with 24% of midwives and 21% of midwifery students (p<0.001). More than half of the midwives (53%) had concerns about the COVID-19 vaccine for the women in their care compared with 35% of doctors and 46% of midwifery students. Despite national guidelines recommending vaccination of breastfeeding women, 54% of practitioners were unlikely to recommend vaccination for this group. This is the first study to explore the perceptions and intentions regarding COVID-19 vaccination from the perspective of those who receive and provide maternity care in Australia. Findings have utility to support targeted public health messaging for these and other cohorts.
Intermittency in the Magnetic Hump in the VLISM Burlaga, L. F.; Berdichevsky, D. B.; Jian, L. K. ...
Astrophysical journal/The Astrophysical journal,
03/2024, Letnik:
964, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract Voyager 1 has been moving through the very local interstellar medium (VLISM) for ∼1 solar cycle, from 122.58 au on 2012/DOY 238 (August 25) to 158.5 au on 2023.0. A magnetic hump was ...observed, beginning with an abrupt increase (jump) in the magnetic field strength B and proton density N by a factor of 1.35 and 1.36, respectively, in the course of ∼8 days, ending at ∼2020/DOY 147, after which it remained above the pre-jump levels for 2.6 yr, and it is still increasing. Unlike the three previous jumps, which were followed by a slow decrease in B , B in the magnetic hump continued to increase to a maximum value ∼0.56 nT at ∼2021/DOY 146.7. This paper discusses the intermittency of the magnetic field components and strength in the magnetic hump, and compares them with previous values in the VLISM. We consider the intermittency of the increments of B and its components observed on a scale of one day. The distribution function (the Tsallis distribution or q -distribution function) of the increments of hourly averages of the components of B had a Gaussian core associated with randomness in the observations, and it had two symmetric tails associated with the observed intermittency. The parameters q -dBR1, q -dBT1, and q -dBN1 increased slightly to a broad maximum with q = ∼1.4 between 2018 and 2019, and then decreased to q ∼ 1 (corresponding to no intermittency) in 2022. The Z -component of the magnetic field is within 4 ± 4 counts (0.02 nT ± 0.02 nT).
Abstract
Voyager 1 has been moving through the very local interstellar medium (VLISM) for approximately one solar cycle, from 122.58 au on 2012/DOY 238 (August 25) to 158.5 au on 2023.0. Previously, ...an abrupt increase (“jump”) in the magnetic field strength
B
and proton density
N
by a factor of 1.35 and 1.36, respectively, was observed during an interval of ∼8 days in 2020.40. After the jump,
B
continued to increase to a maximum value ∼0.56 nT at ∼2021.4 and then declined until
B
returned to the postjump value of 0.5 nT on 2021.85, 1.45 yr after the jump. The magnetic field strength declined briefly from 0.5 nT on 2021.85 to 0.47 nT on 2021.95 and then increased sporadically to 0.52 nT at 2023.0. Thus, the magnetic field strength remained strong for at least 2.6 yr. The magnetic hump and the density hump were a compression wave propagating through the VLISM. The compression wave was generated by a region with large dynamic pressure in the solar wind that propagated through the inner heliosheath and collided with the heliopause. The magnetic field strength continued to remain strong, with slow variations, until the end of our observations at 2023.0. It is suggested that the magnetic hump evolved from the large dynamic pressure, high speeds, and density observed at 1 au between ∼2015 and ∼2017.
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