Magnetic resonance imaging for diagnostic workup of Embolic Stroke of Undetermined Source: a systematic review

Background: Embolic stroke of undetermined source (ESUS) refers to ischemic stroke where the underlying cause of thromboembolism cannot be found despite the recommended diagnostic workup. Unidentified source of emboli hinders clinical decision-making and patient management with detrimental consequences on long-term prognosis. The rapid development and versatility of magnetic resonance imaging (MRI) make it an appealing addition to the diagnostic routine of patients with ESUS for the assessment of potential vascular and cardiac embolic sources. Aims: To review the use of MRI in the identification of cardiac and vascular embolic sources in ESUS and to assess the reclassification value of MRI examinations added to the conventional workup of ESUS. Summary of review: We reviewed the use of cardiac and vascular MRI for the identification of a variety of embolic sources associated with ESUS, including atrial cardiomyopathy, left ventricular pathologies, and supracervical atherosclerosis in carotid and intracranial arteries and in distal thoracic aorta. The additional reclassification after MRI examinations added to the workup of patients with ESUS ranged from 6.1% to 82.3% and varied depending on the combination of imaging modalities. Conclusion: MRI techniques allow us to identify additional cardiac and vascular embolic sources and may further decrease the prevalence of patients with the diagnosis of ESUS

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

POTENCIAL ANSIOLÍTICO DO GÊNERO Citrus: REVISÃO INTEGRATIVA DA LITERATURA

A alta prevalência de pessoas acometidas por algum distúrbio de ansiedade associada aos efeitos colaterais da farmacoterapia a longo prazo tem motivado a procura por novas terapias. Como terapia complementar e alternativa, óleos essenciais e infusos obtidos de folhas, cascas e flores de muitas espécies do gênero Citrus têm sido utilizadas pela população para minimizar distúrbios emocionais e tem sido recomendado no tratamento da ansiedade. O presente estudo buscou analisar a literatura publicada referente ao potencial ansiolítico do gênero Citrus, através de uma revisão integrativa nas bases de dados: MEDLINE, PubMed, SciELO e LILACS, no período de Janeiro a Abril de 2014, utilizando os descritores ansiedade e Citrus e selecionados 12 artigos que compuseram a amostra do estudo. Em todos os artigos selecionados foi demonstrado o potencial ansiolítico do gênero Citrus, o qual se atribui à atividade sinérgica ou isolada dos metabólitos presentes nestes extratos e/ou óleos essenciais estudados, que se assemelham. Diante dos resultados satisfatórios já realizados em humanos, observa-se a importância e a necessidade de maiores estudos e investimentos no sentido de tornar possível a utilização desses compostos de origem natural e de fácil acesso à população na terapêutica

IXPE Observations of the Blazar Mrk 501 in 2022: A Multiwavelength View

The blazar Markarian 501 (Mrk 501) was observed on three occasions over a 4-month period between 2022 March and 2022 July with the Imaging X-ray Polarimetry Explorer (IXPE). In this paper, we report for the first time on the third IXPE observation, performed between 2022 July 9 and 12, during which IXPE detected a linear polarization degree of ΠX = 6 ± 2 per cent at a polarization angle, measured east of north, of ΨX = 143○ ± 11○ within the 2 – 8 keV X-ray band. The X-ray polarization angle and degree during this observation are consistent with those obtained during the first two observations. The chromaticity of the polarization across radio, optical, and X-ray bands is likewise consistent with the result from the simultaneous campaigns during the first two observations. Furthermore, we present two types of models to explain the observed spectral energy distributions (SEDs) and energy-resolved polarization: a synchrotron self-Compton model with an anisotropic magnetic field probability distribution in the emitting volume, as well as an energy-stratified shock model. Our results support both the shock scenario as well as support that small levels of magnetic field anisotropy can explain the observed polarization

Portois & Fix Building

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ATPase-Independent Type-III Protein Secretion in Salmonella enterica.

Type-III protein secretion systems are utilized by gram-negative pathogens to secrete building blocks of the bacterial flagellum, virulence effectors from the cytoplasm into host cells, and structural subunits of the needle complex. The flagellar type-III secretion apparatus utilizes both the energy of the proton motive force and ATP hydrolysis to energize substrate unfolding and translocation. We report formation of functional flagella in the absence of type-III ATPase activity by mutations that increased the proton motive force and flagellar substrate levels. We additionally show that increased proton motive force bypassed the requirement of the Salmonella pathogenicity island 1 virulence-associated type-III ATPase for secretion. Our data support a role for type-III ATPases in enhancing secretion efficiency under limited secretion substrate concentrations and reveal the dispensability of ATPase activity in the type-III protein export process

Schematic overview of the flagellar transcriptional hierarchy and biogenesis.

<p>The flagellar transcriptional hierarchy of <i>Salmonella enterica</i> is composed of three classes of promoters. The Class I promoter transcribes a single operon encoding for the master regulator of the flagellar transcriptional hierarchy, the FlhD₄C₂ complex, which is negatively regulated by ClpXP protease. FlhD₄C₂, together with σ⁷⁰, directs RNA polymerase to transcribe from Class II promoters. Genes transcribed from Class II promoters encode structural components of the hook-basal-body complex (shaded in blue), the flagellar type-III secretion apparatus (composed of the membrane proteins FlhA, FlhB, FliO, FliP, FliQ and FliR; and the soluble proteins FliH, FliI and FliJ), as well as regulatory proteins, in particular the flagellar-specific σ-factor, σ²⁸ (encoded by <i>fliA</i>), and its cognate anti-σ factor, FlgM. The hook-basal-body is completed as soon as the hook reaches an approximate length of 55 nm, upon which the type-III secretion apparatus switches secretion specificity to its late-substrate secretion mode (indicated by the orange star). Subsequently, the late substrate FlgM is exported out of the cell, thereby freeing σ²⁸ to turn on transcription from Class III promoters. Class III gene products include the filament subunits, motor-force generators and the chemotactic system (shaded in red).</p

Lengths of flagellar filaments in <i>fliHIJ</i> mutants.

<p>Plot showing the lengths of individual flagellar filaments of the <i>fliHIJ</i> mutants visualized by anti-FliC immunostaining in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004800#pgen-1004800-g003" target="_blank">Figure 3</a> and <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1004800#pgen-1004800-g004" target="_blank">Figure 4</a>. The average lengths of flagellar filaments +/− standard deviation and the number of measured filaments are presented in the upper part of the graph.</p

Flagellin protein secretion is restored in the absence of FliHIJ ATPase components by Δ<i>atpA</i>, <i>ΔflgM</i>, <i>ΔclpX</i>, and <i>fliA^H14D</i> mutations.

<p>Secreted FliC flagellin protein was analyzed by anti-FliC immunostaining in the FliC-phase locked wildtype and <i>fliHIJ</i> mutant strains. (<b>A</b>) Wildtype and <i>fliHIJ</i> mutants in combination with Δ<i>atpA</i>. (<b>B</b>) Wildtype and <i>fliHIJ</i> mutants in combination with Δ<i>flgM</i> and Δ<i>atpA</i>. (<b>C</b>) Wildtype and <i>fliHI</i> deletion mutant in combination with Δ<i>clpX</i> and Δ<i>atpA</i>. (<b>D</b>) Wildtype and <i>fliHI</i> deletion mutant in combination with <i>fliA^H14D</i> and Δ<i>atpA</i>.</p