Abstract
We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the ...source star of the long-duration (
t
E
≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of 6 yr, reveals a clear relativistic astrometric deflection of the background star’s apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of Earth’s motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 ± 1.3
M
⊙
and a distance of 1.58 ± 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic disk stars at similar distances by an amount corresponding to a transverse space velocity of ∼45 km s
−1
, suggesting that the BH received a “natal kick” from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial velocity measurements of Galactic X-ray binaries and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique.
Background and Purpose- The increasing demand and shortage of experts to evaluate and treat acute stroke patients has led to the development of remote communication tools to aid stroke management. We ...aimed to evaluate the JOIN App smartphone system-a low-cost tool for rapid clinical and neuroimaging data sharing to expedite decision-making in stroke. Methods- Consecutive acute ischemic stroke patients treated at a University Hospital in Brazil from December 2014 to December 2015 were evaluated. The analysis included all patients presenting with acute ischemic stroke who underwent initial evaluation by neurology residents followed by JOIN teleconsultation with a stroke neurologist on call for management decisions. An expert panel of stroke neurologists and neuroradiologists revised all cases using a standard Picture Archiving and Communication System imaging workstation within 24 hours and analyzed the decision made with remote assistance during the emergency setting. Results- A total of 720 stroke codes were evaluated with 442 acute ischemic stroke qualifying. Seventy-eight (18%) patients were treated with intravenous thrombolysis. The main reasons for tPA (tissue-type plasminogen activator) exclusion were symptom onset >4.5 hours (n=295; 67%) and hypodense middle cerebral artery territory area >1/3 (n=31; 7%). The agreement rates between Picture Archiving and Communication System versus JOIN-based thrombolysis decisions were 100% for the stroke (unblinded) and 99.3% for the neuroradiologist (blinded) experts. The use of the application resulted in a significant reduction in the door-to-needle times across the pre- versus postimplementation periods (median, 90 interquartile range, 75-106 versus 63 interquartile range, 61-117 minutes;
=0.03). The rates of 90-day excellent outcomes (modified Rankin Scale, 0-1) were 51.3%; 90-day mortality, 2.6%; and symptomatic intracranial hemorrhage, 3.8%. Conclusions- The JOIN smartphone system allows rapid sharing of clinical and imaging data to facilitate decisions for stroke treatment. The remote application-based decisions seem to be as accurate as the physical presence of stroke experts and might lead to faster times to treatment. This system represents an easily implementable low-cost telemedicine solution for centers that cannot afford the full-time presence of stroke specialists.
The massive O4.5 V + O5.5 V binary VFTS 352 in the Tarantula Nebula is one of the shortest-period and most massive overcontact binaries known. Recent theoretical studies indicate that some of these ...systems could ultimately lead to the formation of gravitational waves via black hole binary mergers through the chemically homogeneous evolution pathway. By analyzing ultraviolet-optical phase-resolved spectroscopic data, we aim to constrain atmospheric and wind properties that could be later used to confront theoretical predictions from binary evolution. In particular, surface abundances are powerful diagnostics of the evolutionary status, mass transfer, and internal mixing processes. From a set of 32 Very Large Telescope/FLAMES visual and eight Hubble Space Telescope/Cosmic Origins Spectrograph ultraviolet spectra, we used spectral disentangling to separate the primary and secondary components. Using a genetic algorithm wrapped around the NLTE model atmosphere and the spectral synthesis code fastwind, we perform an 11-parameter optimization to derive the atmospheric and wind parameters of both components, including the surface abundances of He, C, N, O, and Si. We find that both components are hotter than expected compared to single-star evolutionary models, indicating that additional mixing processes may be at play. However, the derived chemical abundances do not show significant indications of mixing when adopting baseline values typical of the system environment.
ABSTRACT
Westerlund 1 (Wd 1) is one of the most massive young star clusters in the Milky Way. Although relevant for star formation and evolution, its fundamental parameters are not yet very well ...constrained. We aim to derive an accurate distance and provide constraints on the cluster age. We used the photometric and astrometric information available in the Gaia Early Data Release 3 (Gaia-EDR3) to infer its distance of 4.06$^{+0.36}_{-0.34}$ kpc. Modelling of the eclipsing binary system W36, reported in Paper II, led to the distance of 4.03 ± 0.25 kpc, in agreement with the Gaia-EDR3 distance and, therefore, validating the parallax zero-point correction approach appropriate for red objects. The weighted average distance based on these two methods results in dwd1 = 4.05 ± 0.20 kpc (m − M = 13.04$^{+0.11}_{-0.12}$ mag), which has an unprecedented accuracy of 5 per cent. Using the Binary Population and Spectral Synthesis (BPASS) models for the Red Supergiants with solar abundance, we derived an age of 10.7 ± 1 Myr, in excellent agreement with recent work by Beasor & Davies (10.4$^{+1.3}_{-1.2}$ Myr) based on MIST evolutionary models. In Paper II, W36B was reported to be younger than 7.1 Myr, supporting recent claims of a temporal spread of several Myrs for the star-forming process within Wd 1 instead of a single monolithic starburst episode scenario.
Abstract
Background
Trichosporon fungaemia (TF) episodes have increased in recent years and mortality rates remain high despite the advances in the management of sepsis. New concepts about its ...clinical course, treatment and microbiology need to be investigated for the better management of this infection.
Objectives
To describe the aetiology, natural history, clinical management and prognostic factors of TF.
Methods
TF episodes documented between 2005 and 2018 in 23 South American centres were retrospectively investigated by using a standard clinical form. Molecular identification, antifungal susceptibility testing and biofilm production were also performed.
Results
Eighty-eight TF episodes were studied. Patients had several underlying conditions, including haematological diseases (47.7%), post-operative status (34%), solid organ transplants (n = 7, 7.9%), among others. Seventy-three (82.9%) patients had a central venous catheter (CVC) at TF diagnosis. The 30 day mortality rate was 51.1%. Voriconazole-based therapy was given to 34 patients (38.6%), with a 30 day mortality rate of 38.2%. Multivariate predictors of 30 day mortality were age (OR 1.036), mechanical ventilation (OR 8.25) and persistent neutropenia (OR 9.299). CVC removal was associated with over 75% decreased risk of 30 day mortality (OR 0.241). Microbiological analyses revealed that 77.7% of the strains were identified as Trichosporon asahii, and voriconazole showed the strongest in vitro activity against Trichosporon spp. Most of the strains (63%) were considered medium or high biofilm producers.
Conclusions
Older age, mechanical ventilation and persistent neutropenia were associated with poor prognosis. CVC may play a role in the pathogenicity of TF and its removal was associated with a better prognosis.
ABSTRACT
Westerlund 1 (Wd 1) is one of the most relevant star clusters in the Milky Way to study massive star formation, although it is still poorly known. Here, we used photometric and spectroscopic ...data to model the eclipsing binary W36, showing that its spectral type is O6.5 III + O9.5 IV, hotter and more luminous than thought before. Its distance dW36 = 4.03 ± 0.25 kpc agrees, within the errors, with three recent Gaia-EDR3-based distances reported in Paper I, Beasor & Davies, and by Negueruela’s group. However, they follow different approaches to fix the zero-points for red sources such as those in Wd 1, and to select the best approach, we used an accurate modelling of W36. The weighted mean distance of our parallax (Paper I) and binary distances results in dwd1 = 4.05 ± 0.20 kpc, with an unprecedented accuracy of 5 per cent. We adopted isochrones based on the Geneva code with supersolar abundances to infer the age of W36B as 6.4 ± 0.7 Myr. This object seems to be part of the prolific star formation burst represented by OB giants and supergiants that occurred at 7.1 ± 0.5 Myr ago, which coincides with the recently published PMS isochrone with age 7.2 Myr. Other BA-type luminous evolved stars and yellow hypergiants spread in the age range of 8–11 Myr. The four red supergiants discussed in paper I represent the oldest population of the cluster with an age of 10.7 ± 1 Myr. The multiple episodes of star formation in Wd 1 are reminiscent of that reported for the R136/30 Dor LMC cluster.
Carbon nanohorns (CNH) have been considered potential anticancer drug carriers, such as the cisplatin drug (cddp), due to their low toxicity, high purity, drug-loading capacity, and biodegradation ...routes. However, when it comes to nanomedicine applications, chemical functionalization is an essential step in order to overcome undesirable properties of these nanomaterials, such as the high hydrophobicity, low reactivity, and low dispersibility in polar solvents. In this context, the present study involved the modeling of new CNH topologies based on chemical oxidation and reduction mechanisms and the investigation of the influence of these modified structures on the dynamics and stability of inclusion complexes with cddp. The results indicated that these functionalization strategies lead to the opening of nanowindows on the CNH surfaces, which would constitute the main route for drug release, as reported by experimentalists. Also, our results showed that the insertion of polar functional groups on the oxidized CNH (CNHox-N) contributed to an improvement of the cddp@CNHox-N biocompatibility due to the greater number of hydrogen bonds formed with the solvent. Despite the favorable formation of all complexes, the binding free energies pointed out that the oxidation process made the cddp@CNHox-N complexes slightly less stable than the ones with pristine and reduced CNH. Besides, the results suggest the possibility to tune the complex stability by controlling the oxidation degree, which could be explored by the experimentalists in order to design controlled drug delivery systems based on CNH nanocarriers.
IL-10 is a cytokine that regulates the balance between pathogen clearance and immunopathology. Brucella abortus is an intracellular bacterium that causes chronic disease in humans and domestic ...animals. Here we evaluated the contribution of IL-10 in host immune response and pathology during B. abortus infection. To assess the role of IL-10 in vivo, IL-10 knockout (KO) or 129 Sv/Ev (wild-type) mice were infected with B. abortus and the number of viable bacteria from the spleen was determined at 1, 2, 3, 6 and 14-weeks postinfection. IL-10 KO mice showed reduced bacterial loads in the spleen when compared to wild-type mice during all time points studied. Additionally, at 14-weeks postinfection IL-10 KO mice had totally cleared the infection. This clearance was preceded by an enhanced IFN-γ, TNF-α and IL-17 responses in both the serum and the spleen of IL-10 KO mice. Additionally, dendritic cells from infected IL-10 KO mice produced elevated levels of IL-12 and TNF-α compared to wild-type animals. Histopathology analysis was performed and both KO and wild-type mice developed multifocal granulomas and necrosis in the liver. However, at six-weeks postinfection reduced numbers of granulomas was detected in IL-10 KO mice compared to wild-type animals. This reduced liver pathology at later stage of infection was accompanied by increased numbers of CD4+CD25+foxp3+ T cells and expression of TGF-β in IL-10 KO splenocytes. Taken together, our findings demonstrate that IL-10 modulates the proinflammatory immune response to B. abortus infection and the lack of IL-10 increases resistance to Brucella infection.
ABSTRACT
The study of the orbital period variation of short-period binary systems has been important to understand several physical phenomena, such as the emission of gravitational waves, angular ...momentum loss via magnetic braking, matter transfer between the components, apsidal motion, quadrupole moment variation, and presence of circumbinary bodies. With the advent of large space missions, e.g. Kepler and Transiting Exoplanet Survey Satellite (TESS), an enormous amount of high-precision photometric data with temporal coverage from years to decades has become available. Thus, in this work, we propose to study the orbital period variation of a sample of 253 binary that was observed by both Kepler and TESS and therefore with a temporal coverage of more than 10 yr. The main goal of this paper is the search and characterization of third bodies. Based on the periodicity analysis of the observed minus calculated (O − C) diagram of the sample, 75 of them showed periodic variation and therefore were classified as binary systems with third-body candidates, while the remaining 178 did not show periodic variations. This result is a two-fold increase in tertiary candidates around binary systems compared to the study carried out with only Kepler data. Although our estimated rate of third-body candidates (∼30 per cent) is higher than that obtained only with Kepler data (∼20 per cent), it should be taken as a lower limit.
The medication with Pt-based antitumor drug cisplatin has demonstrated effective results against cancer cells, despite the severe side effects due to the high toxicity associated with the low ...selectivity of these anticancer agents. An alternative to overcome or decrease the side effects is to use drug delivery systems, which can carry high doses of the anticancer drug and promote its slow and targeted release to the tumor sites. Herein, we used molecular dynamics to study prototypes of the complexes formed by the encapsulated cisplatin and carbon nanohorns (CNH), with the purpose to characterize its structures and dynamical behavior in aqueous solution, an important feature to assess the potentiality of using CNH as carrier systems. The results indicated the presence of up to 36 water molecules inside the empty CNH cavity, depending on the cone angle and the presence of the cisplatin. Some of these solvent molecules are expelled out to the bulk upon cisplatin inclusion, although more than 10 molecules remain even for the narrow structures. Moreover, the calculated binding free energy (ΔbG) pointed out that the inclusion complexes formation between CNH structures and up to two cisplatin molecules was thermodynamically favorable in aqueous media, which suggests the potentiality of these carbon nanostructures as drug carriers. For the most likely and narrow host structure the average ΔbG was −92.0 kcal mol−1 for inclusion of two cisplatin, with most of the complex stability coming from the van der Waals contribution.
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•Carbon nanohorns are evaluated as drug delivery systems for cisplatin.•The carbon carriers accommodate up to two drug molecules inside the cavity.•The molecular complex stability can be tune by changing the angle of the cone.•The inner solvation shell keeps the cisplatin inside the cavity.
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