A review of severe acute respiratory syndrome - coronavirus 2

The pandemic caused by SARS-CoV-2 in 2020 and still raging in 2021 is a global emergency where no country was spared from its high morbidity and mortality. Life changed in innumerable ways, from lock downs to job losses, isolation and mental health crisis. All countries suffered. If it were not for the quick development of medications and vaccines, coupled with preventive measures like facial masks, social distancing and frequent washing of hands, we will be in a worse chaos. Some countries like India and many in Latin America have been devastated and its consequences will be long felt even after the pandemic is controlled. Understanding the cause, its epidemiology and controlled measures is important. Although it took 100 years to encounter a global pandemic of this magnitude, scientists warn of almost inevitable future global pandemics. This review will explore some salient aspects of SARS-CoV-2 impact and measures to control the infection. The world’s death toll caused by SARS-CoV-2 exceeds 3 million and close to 200 million people have been infected. The available vaccines used in more than 400 million individuals, still fall short of producing herd immunity despite the high efficacy rate of most of them. There is a pressing need to immunize 80% or more. Some side effects to vaccine were reported, the majority of minor impact, although some rare ones are more serious such as thrombotic thrombocytopenia or myocarditis. Still the protection afforded from the vaccine vastly outweighs the risks and its wide use is encouraged.The pandemic caused by SARS-CoV-2 in 2020 and still raging in 2021 is a global emergency where no country was spared from its high morbidity and mortality. Life changed in innumerable ways, from lock downs to job losses, isolation and mental health crisis. All countries suffered. If it were not for the quick development of medications and vaccines, coupled with preventive measures like facial masks, social distancing and frequent washing of hands, we will be in a worse chaos. Some countries like India and many in Latin America have been devastated and its consequences will be long felt even after the pandemic is controlled. Understanding the cause, its epidemiology and controlled measures is important. Although it took 100 years to encounter a global pandemic of this magnitude, scientists warn of almost inevitable future global pandemics. This review will explore some salient aspects of SARS-CoV-2 impact and measures to control the infection. The world’s death toll caused by SARS-CoV-2 exceeds 3 million and close to 200 million people have been infected. The available vaccines used in more than 400 million individuals, still fall short of producing herd immunity despite the high efficacy rate of most of them. There is a pressing need to immunize 80% or more. Some side effects to vaccine were reported, the majority of minor impact, although some rare ones are more serious such as thrombotic thrombocytopenia or myocarditis. Still the protection afforded from the vaccine vastly outweighs the risks and its wide use is encouraged

Monolithic millimeter-wave diode grid frequency multiplier arrays

Monolithic diode frequency multiplier arrays, including barrier-N-N(+) (BNN) doubler, multi-quantum-barrier-varactor (MQBV) tripler, Schottky-quantum-barrier-varactor (SQBV) tripler, and resonant-tunneling-diode (RTD) tripler arrays, have been successfully fabricated with yields between 85 and 99 percent. Frequency doubling and/or tripling have been observed for all the arrays. Output powers of 2.4-2.6 W (eta = 10-18 percent) at 66 GHz with the BNN doubler and 3.8-10 W (eta = 1.7-4 percent) at 99 GHz with the SQBV tripler have been achieved

Monolithic millimeter-wave diode array beam controllers: Theory and experiment

In the current work, multi-function beam control arrays have been fabricated and have successfully demonstrated amplitude control of transmitted beams in the W and D bands (75-170 GHz). While these arrays are designed to provide beam control under DC bias operation, new designs for high-speed electronic and optical control are under development. These arrays will fill a need for high-speed watt-level beam switches in pulsed reflectometer systems under development for magnetic fusion plasma diagnostics. A second experimental accomplishment of the current work is the demonstration in the 100-170 GHz (D band) frequency range of a new technique for the measurement of the transmission phase as well as amplitude. Transmission data can serve as a means to extract ('de-embed') the grid parameters; phase information provides more complete data to assist in this process. Additional functions of the array beam controller yet to be tested include electronically controlled steering and focusing of a reflected beam. These have application in the areas of millimeter-wave electronic scanning radar and reflectometry, respectively

Effect of humidity on nitric acid uptake to mineral dust aerosol particles

International audienceThis study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD), SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labeled gaseous nitric acid was observed in a flow reactor on the 0.2?2 s reaction time scale at room temperature and atmospheric pressure. The amount of nitric acid appearing in the aerosol phase at the end of the flow tube was found to be a linear function of the aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the rate of uptake of HNO3 to mineral dust. The fact that the rate of uptake was smaller at a concentration of 1012 than at 1011 was indicative of a complex uptake mechanism. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm-3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , which was attributed to an increasing degree of solvation of the more basic minerals. The extended processing of the dust by higher concentrations of HNO3 at 85% RH led to a water soluble coating on the particles and enhanced their hygroscopicity

Neurofilament light protein levels in cerebrospinal fluid predict long-term disability of Guillain-Barre syndrome: A pilot study

Objectives: Although the recovery from Guillain‐Barré syndrome (GBS) is good in most patients, some develop permanent severe disability or even die. Early predictors would increase the likelihood to identify patients at risk for poor outcome at the acute stage, allowing them intensified therapeutic intervention. Materials and Method: Eighteen patients with a history of GBS 9‐17 years ago were reassessed with scoring of neurological disability and quality of life assessment (QoL). Their previous diagnostic work‐up included clinical examination with scoring of disability, neurophysiological investigation, a battery of serology tests for infections, and cerebrospinal fluid (CSF) examination. Aliquots of CSF were frozen, stored for 20‐28 years, and analyzed by ELISA for determination of neurofilament light protein (NFL) and glial fibrillary acidic protein (GFAP). Results: Patients with poor outcome (n = 3) had significantly higher NFL and GFAP levels at GBS nadir than those with good outcome (n = 15, P < .01 and P < .05, respectively). High NFL correlated with more prominent disability and worse QoL at long‐term follow‐up (r = .694, P < .001, and SF 36 dimension physical component summary (PCS) (r =−.65, P < .05), respectively, whereas GFAP did not correlate with clinical outcome or QoL. Conclusion: High NFL in CSF at the acute stage of GBS seems to predict long‐term outcome and might, together with neurophysiological and clinical measures, be useful in treatment decisions and clinical care of GBS

Evidence of two viscous relaxation processes in the collective dynamics of liquid lithium

New inelastic X-ray scattering experiments have been performed on liquid lithium in a wide wavevector range. With respect to the previous measurements, the instrumental resolution, improved up to 1.5 meV, allows to accurately investigate the dynamical processes determining the observed shape of the the dynamic structure factor, $S(Q,\omega)$. A detailed analysis of the lineshapes shows the co-existence of relaxation processes with both a slow and a fast characteristic timescales, and therefore that pictures of the relaxation mechanisms based on a simple viscoelastic model must be abandoned.Comment: 5 pages, 4 .PS figure

The NR4A subgroup: immediate early response genes with pleiotropic physiological roles

The nuclear hormone receptor (NR) superfamily includes the orphan NR4A subgroup, comprised of Nur77 (NR4A1), Nurr1 (NR4A2) and NOR-1 (NR4A3). These NRs are classified as early response genes, are induced by a diverse range of signals, including fatty acids, stress, growth factors, cytokines, peptide hormones, phorbol esters, neurotransmitters, and physical stimuli (for example magnetic fields, shear stress). The ability to sense and rapidly respond to changes in the cellular environment thus appears to be a hallmark of this subfamily. The members of the NR4A subgroup are well conserved in the DNA binding domain (~91-95%) and the C-terminal ligand-binding domain (~60%), but are divergent in the N-terminal AB region. These receptors bind as monomers, homodimers and heterodimers with RXRs (to mediate retinoid signaling) to different permutations of the canonical NR binding motif. The NR4A subgroup activates gene expression in a constitutive ligand-independent manner. NR4A-mediated trans-activation (LBD) involves unusually active N-terminal AF-1 domains that mediate coactivator recruitment. Moreover, the NR4A receptors encode atypical LBDs and AF-2 domains. For example, the LBDs contain no cavity due to bulky hydrophobic residue side chains, and lack the classical coactivator-binding cleft constituted by helices 3, 4 and 12. However, a hydrophobic patch exists between helices 11 and 12, that encodes a novel cofactor interface that modulates transcriptional activity. In line with the pleiotropic physiological stimuli that induce the NR4A subgroup, these orphan NRs have been implicated in cell cycle regulation (and apoptosis), neurological disease, steroidogenesis, inflammation, carcinogenesis and atherogenesis

Evidence of short time dynamical correlations in simple liquids

We report a molecular dynamics (MD) study of the collective dynamics of a simple monatomic liquid -interacting through a two body potential that mimics that of lithium- across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e. to the dephasing of the different momentum $Q$ Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of {\it un-correlated} binary collisions, the short time particles motion is strongly {\it correlated} and can be described via a normal mode expansion of the atomic dynamics.Comment: 7 pages, 7 .eps figs. To appear in Phys. Rev.

Inelastic X-ray scattering study of the collective dynamics in liquid sodium

Inelastic X-ray scattering data have been collected for liquid sodium at T=390 K, i.e. slightly above the melting point. Owing to the very high instrumental resolution, pushed up to 1.5 meV, it has been possible to determine accurately the dynamic structure factor, $S(Q,\omega)$, in a wide wavevector range, $1.5 \div 15$ nm$^{-1}$, and to investigate on the dynamical processes underlying the collective dynamics. A detailed analysis of the lineshape of $S(Q,\omega)$, similarly to other liquid metals, reveals the co-existence of two different relaxation processes with slow and fast characteristic timescales respectively. The present data lead to the conclusion that: i) the picture of the relaxation mechanism based on a simple viscoelastic model fails; ii) although the comparison with other liquid metals reveals similar behavior, the data do not exhibit an exact scaling law as the principle of corresponding state would predict.Comment: RevTex, 7 pages, 6 eps figures. Accepted by Phys. Rev.

Hygroscopicity of the submicrometer aerosol at the high-alpine site Jungfraujoch, 3580 m a.s.l., Switzerland

Data from measurements of hygroscopic growth of submicrometer aerosol with a hygroscopicity tandem differential mobility analyzer (HTDMA) during four campaigns at the high alpine research station Jungfraujoch, Switzerland, are presented. The campaigns took place during the years 2000, 2002, 2004 and 2005, each lasting approximately one month. Hygroscopic growth factors (&lt;i&gt;GF&lt;/i&gt;, i.e. the relative change in particle diameter from dry diameter, &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;, to diameter measured at higher relative humidity, RH) are presented for three distinct air mass types, namely for: 1) free tropospheric winter conditions, 2) planetary boundary layer influenced air masses (during a summer period) and 3) Saharan dust events (SDE). The &lt;i&gt;GF&lt;/i&gt; values at 85% RH (&lt;i&gt;D&lt;/i&gt;&lt;sub&gt;0&lt;/sub&gt;=100 nm) were 1.40&amp;plusmn;0.11 and 1.29&amp;plusmn;0.08 for the first two situations while for SDE a bimodal &lt;i&gt;GF&lt;/i&gt; distribution was often found. No phase changes were observed when the RH was varied between 10–90%, and the continuous water uptake could be well described with a single-parameter empirical model. The frequency distributions of the average hygroscopic growth factors and the width of the retrieved growth factor distributions (indicating whether the aerosol is internally or externally mixed) are presented, which can be used for modeling purposes. &lt;br&gt;&lt;br&gt; Measurements of size resolved chemical composition were performed with an aerosol mass spectrometer in parallel to the &lt;i&gt;GF&lt;/i&gt; measurements. This made it possible to estimate the apparent ensemble mean &lt;i&gt;GF&lt;/i&gt; of the organics (&lt;i&gt;GF&lt;/i&gt;&lt;sub&gt;org&lt;/sub&gt;) using inverse ZSR (Zdanovskii-Stokes-Robinson) modeling. &lt;i&gt;GF&lt;/i&gt;&lt;sub&gt;org&lt;/sub&gt; was found to be ~1.20 at &lt;i&gt;a&lt;/i&gt;&lt;sub&gt;w&lt;/sub&gt;=0.85, which is at the upper end of previous laboratory and field data though still in agreement with the highly aged and oxidized nature of the Jungfraujoch aerosol