The review provides comparison of porous materials that act as a matrix for luminescent oxygen indicators. These include silica-gels, sol–gel materials based on silica and organically modified silica ...(Ormosils), aerogels, electrospun polymeric nanofibers, metal–organic frameworks, anodized alumina, and various other microstructured sensor matrices. The influence of material structure and composition on the efficiency of oxygen quenching and dynamic response times is compared and the advantages and disadvantages of the materials are summarized to give a guide for design and practical application of sensors with desired sensitivity and response time.
Graphical abstract
Context.
Open clusters provide unambiguous clues to understand the evolution of
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Li at the surface of low-mass stars and its possible correlation with stellar rotation, which is a challenge for both ...stellar hydrodynamics and Galactic chemical evolution.
Aims.
We aim to quantify the efficiency of the transport processes for both angular momentum and chemicals that are required to explain simultaneously the observed behaviour of surface
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Li (and
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Be) and rotation as well as the internal rotation profiles inferred from helio- and asteroseismology in F- and G-type main sequence stars.
Methods.
We apply the model for the transport of angular momentum and chemicals that we tailored in a previous work for solar-type stars to an extended range of initial masses and metallicities corresponding to F- an G-type stars in a sample of 20 Galactic open clusters. We evaluate its ability to explain the
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Li,
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Be, and rotation periods observations. This model includes atomic diffusion, rotation-induced processes (for which we tested different prescriptions for shear turbulence), penetrative convection with a rotational dependence, parametric viscosity and turbulence, and magnetic braking.
Results.
Over the entire range of masses, metallicities, and ages explored, we reproduce the evolution of the surface rotation rates and predict, for the first time, the observed anti-correlation between the surface rotation rate and
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Li depletion as a consequence of the penetrative convection prescription. The
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Li behaviour and its evolution with time is well reproduced for G-type stars. However, the ability of the model to reproduce the so-called
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Li dip centred around ∼6600 K strongly depends on the adopted prescriptions for shear turbulence. It also requires a stellar mass dependence for the parametric viscosity adopted for the transport of angular momentum, similar to the behaviour predicted for the generation and luminosity of internal gravity waves generated by stellar convective envelopes. Finally, the model predicts internal rotation profiles in good agreement with asteroseismic constraints in main sequence stars.
Conclusions.
We provide an efficient way to model G-type stars of different ages and metallicities successfully. However, the
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Li and
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Be dip constraints urgently call for further hydrodynamical studies to better model turbulence in stars, and for the exploration of physical processes such as tachocline mixing for the transport of chemicals and internal gravity waves for the transport of angular momentum. Finally, additional data for the internal rotation and for
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Be in main sequence low-mass stars are definitively needed.
The inclusion of preliminary chemical labeling (derivatization) in the analysis process by such powerful and widespread methods as electrospray ionization (ESI) and matrix-assisted laser ...desorption/ionization (MALDI) mass spectrometry (MS) is a popular and widely used methodological approach. This is due to the need to remove some fundamental limitations inherent in these powerful analytic methods. Although a number of special reviews has been published discussing the utilization of derivatization approaches, the purpose of the present critical review is to comprehensively summarize, characterize and evaluate most of the previously developed and practically applied, as well as recently proposed representative derivatization reagents for ESI-MS and MALDI-MS platforms in their mostly sensitive positive ion mode and frequently hyphenated with separation techniques. The review is focused on the use of preliminary chemical labeling to facilitate the detection, identification, structure elucidation, quantification, profiling or MS imaging of compounds within complex matrices. Two main derivatization approaches, namely the introduction of permanent charge-fixed or highly proton affinitive residues into analytes are critically evaluated. In situ charge-generation, charge-switch and charge-transfer derivatizations are considered separately. The potential of using reactive matrices in MALDI-MS and chemical labeling in MS-based omics sciences is given.
The analysis of the proton flux variations observed by the Energetic Particle Telescope (EPT) at energies >9.5 MeV from the launch of PROBA‐V satellite on 7 May 2013 up to October 2022 shows an ...anti‐correlation between the proton fluxes and the solar phase. At solar minimum, the fluxes are higher at low L corresponding to the northern border of the South Atlantic Anomaly (SAA). This solar cycle modulation of the inner belt is mainly due to losses by increased atmospheric interactions during solar maximum. Strong Solar Energetic Particle (SEP) events, like in January 2014, June 2015, and September 2017, inject energetic protons at high latitudes, but not in the inner belt where protons are trapped at long term at low L. Nevertheless, big geomagnetic storms, including those following SEP a few days after, can cause losses of protons at the outer border of the proton belt, due to magnetic field perturbations. A double peak in the proton belt is observed during long period of measurements only for the EPT channel of 9.5–13 MeV. The narrow gap between the two peaks in the inner belt is located around L = 2. This resembles to a splitting of the proton belt, separating the SAA into two different parts, North and South. The high‐resolution measurements of PROBA‐V/EPT allow the observation of small‐scale structures that brings new elements to the understanding of the different source and loss mechanisms acting on the proton radiation belt at LEO.
Key Points
PROBA‐V/EPT confirms that proton flux variations in the SAA are mainly due to losses at low L during solar maximum
A splitting of the SAA is observed from 9.5 to 13 MeV corresponding to a double proton belt
Big SEP events of June 2015 and September 2017 have small effects in the SAA that is more affected by geomagnetic storms at its outer edge
Treatment of latent Mycobacterium tuberculosis infection is an essential component of tuberculosis control and elimination. The current standard regimen of isoniazid for 9 months is efficacious but ...is limited by toxicity and low rates of treatment completion.
We conducted an open-label, randomized noninferiority trial comparing 3 months of directly observed once-weekly therapy with rifapentine (900 mg) plus isoniazid (900 mg) (combination-therapy group) with 9 months of self-administered daily isoniazid (300 mg) (isoniazid-only group) in subjects at high risk for tuberculosis. Subjects were enrolled from the United States, Canada, Brazil, and Spain and followed for 33 months. The primary end point was confirmed tuberculosis, and the noninferiority margin was 0.75%.
In the modified intention-to-treat analysis, tuberculosis developed in 7 of 3986 subjects in the combination-therapy group (cumulative rate, 0.19%) and in 15 of 3745 subjects in the isoniazid-only group (cumulative rate, 0.43%), for a difference of 0.24 percentage points. Rates of treatment completion were 82.1% in the combination-therapy group and 69.0% in the isoniazid-only group (P<0.001). Rates of permanent drug discontinuation owing to an adverse event were 4.9% in the combination-therapy group and 3.7% in the isoniazid-only group (P=0.009). Rates of investigator-assessed drug-related hepatotoxicity were 0.4% and 2.7%, respectively (P<0.001).
The use of rifapentine plus isoniazid for 3 months was as effective as 9 months of isoniazid alone in preventing tuberculosis and had a higher treatment-completion rate. Long-term safety monitoring will be important. (Funded by the Centers for Disease Control and Prevention; PREVENT TB ClinicalTrials.gov number, NCT00023452.).
Optical oxygen sensors based on indicators immobilized into porous and nonporous matrix materials were investigated in regard to their sensing behaviour under high hydrostatic pressure. The sensors ...were subjected to step-wise pressure increase up to approximately 200 bar in multiple cycles using a custom-made chamber. The investigated materials are based on oxygen indicators (a platinum(II) benzoporphyrin dye and ruthenium(II) polypyridyl complexes) immobilized in microparticles: silica gels of different porosities, controlled pore glass, poly(phenylsilsesquioxane), crosslinked polystyrene, the metal-organic frameworks ZIF-8 and UiO-66. The microparticles are in turn dispersed in highly oxygen-permeable silicone and Hyflon AD matrices. Homogeneous films of dye doped polystyrene and polyurethane hydrogels as well as non-porous polystyrene nanospheres directly dispersed in water were used for comparison purposes. All the porous materials were found to be stable under elevated hydrostatic pressure. Although the actual oxygen concentration remained unchanged upon increasing pressure, the sensors demonstrated an apparent decrease of calculated oxygen concentration (between −0.02 and −0.45 mg O2 L-1 H2O per 100 bar), which was fully reversible. Furthermore, the kinetics of the pressure response of the sensors was determined in experiments with high temporal resolution. Spikes attributed to pressure-induced oxygen diffusion between sensor components were observed within the first seconds after pressurization/depressurization.
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•Optical oxygen sensors systematically underestimate O2 concentrations at elevated hydrostatic pressure.•This measurement error strongly depends on the components of the sensor material.•Calculated O2 concentration linearly depends on hydrostatic pressure which allows for straightforward correction.•At short timescales, a complex interplay of pressure effects is visible in the sensor response.•The investigated porous sensor materials show high stability up to at least 200 bar hydrostatic pressure.
Background Interferon (IFN)-alpha has been used to study the effects of innate immune cytokines on the brain and behavior in humans. The degree to which peripheral administration of IFN-alpha ...accesses the brain and is associated with a central nervous system (CNS) inflammatory response is unknown. Moreover, the relationship among IFN-alpha-associated CNS inflammatory responses, neurotransmitter metabolism, and behavior has yet to be established. Methods Twenty-four patients with hepatitis C underwent lumbar puncture and blood sampling after ∼12 weeks of either no treatment ( n = 12) or treatment with pegylated IFN-alpha 2b ( n = 12). Cerebrospinal fluid (CSF) and blood samples were analyzed for proinflammatory cytokines and their receptors as well as the chemokine, monocyte chemoattractant protein-1 (MCP-1), and IFN-alpha. Cerebrospinal fluid samples were additionally analyzed for monoamine metabolites and corticotropin releasing hormone. Depressive symptoms were assessed using the Montgomery Asberg Depression Rating Scale. Results Interferon-alpha was detected in the CSF of all IFN-alpha-treated patients and only one control subject. Despite no increases in plasma IL-6, IFN-alpha-treated patients exhibited significant elevations in CSF IL-6 and MCP-1, both of which were highly correlated with CSF IFN-alpha concentrations. Of the immunologic and neurotransmitter variables, log-transformed CSF concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were the strongest predictor of depressive symptoms. Log-transformed CSF concentrations of IL-6, but not IFN-alpha or MCP-1, were negatively correlated with log-transformed CSF 5-HIAA ( r2 = −.25, p < .05). Conclusions These data indicate that a peripherally administered cytokine can activate a CNS inflammatory response in humans that interacts with monoamine (serotonin) metabolism, which is associated with depression.
Aims. We revisit large spectroscopic data sets for field stars from the literature to derive the upper Li envelope in the high metallicity regime in our Galaxy. Methods. We take advantage of Gaia ...EDR3 data and state-of-the-art stellar models to precisely determine the position of the sample dwarf stars in the Hertzsprung-Russell diagram. Results. The highest Li abundances are found in field metal-rich warm dwarfs from the GALAH survey, located on the hot side of the Li-dip. Their mean Li value agrees with what was recently derived for warm dwarfs in metal-rich clusters, pointing towards a continuous increase of Li up to super-solar metallicity. However, if only cool dwarfs are considered in GALAH, as done in the other literature surveys, it is found that the upper Li envelope decreases at super-solar metallicities, blurring the actual Li evolution picture. We confirm the suggestion that field and open cluster surveys that found opposite Li behaviour in the high metallicity regime do not sample the same types of stars: The first ones, with the exception of GALAH, miss warm dwarfs that can potentially preserve their original Li content. Conclusions. Although we can discard the bending of the Li upper envelope at high metallicity derived from the analysis of cool star samples, we still need to evaluate the effects of atomic diffusion on warm, metal-rich early-F and late-A type dwarfs before deriving the actual Li abundance at high metallicity.
Increasing evidence suggests that post-TB lung disease (PTLD) causes significant morbidity and mortality. The aim of these clinical standards is to provide guidance on the assessment and management ...of PTLD and the implementation of pulmonary rehabilitation (PR).
A panel of global experts in the field of TB care and PR was identified; 62 participated in a Delphi process. A 5-point Likert scale was used to score the initial ideas for standards and after several rounds of revision the document was approved (with 100% agreement).
Five clinical standards were defined: Standard 1, to assess patients at the end of TB treatment for PTLD (with adaptation for children and specific settings/situations); Standard 2, to identify patients with PTLD for PR; Standard 3, tailoring the PR programme to patient needs and the local setting; Standard 4, to evaluate the effectiveness of PR; and Standard 5, to conduct education and counselling. Standard 6 addresses public health aspects of PTLD and outcomes due to PR.
This is the first consensus-based set of Clinical Standards for PTLD. Our aim is to improve patient care and quality of life by guiding clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage PTLD.
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The model of the occurrence of translational symmetry as a complex of standing plane elastic waves, forming three-dimensional lattices of their intersection nodes, is proposed based on the results ...of a crystallographic analysis of popular structure types. Criteria of crystal structure stability, characterizing the reduction of atomic degrees of freedom, are proposed taking into account the additional symmetric atomic ordering in the unit-cell volume. The characteristics of some highly symmetrical structures with cubic or hexagonal symmetry are compared. It is proposed to refer to the process of formation of stable states by creating symmetric spatial configurations, which is universal for material particles, as crystal dynamics.
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