The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets. ...There exist a variety of methods in astronomy to estimate or determine it. In this review we present a significant number of such methods, beginning with the most direct and model-independent approach using detached eclipsing binaries. We then move to more indirect and model-dependent methods, such as the quite commonly used isochrone or stellar track fitting. The arrival of quantitative asteroseismology has opened a completely new approach to determine stellar masses and to complement and improve the accuracy of other methods. We include methods for different evolutionary stages, from the pre-main sequence to evolved (super)giants and final remnants. For all methods uncertainties and restrictions will be discussed. We provide lists of altogether more than 200 benchmark stars with relative mass accuracies between
0.3
,
2
%
for the covered mass range of
M
∈
0.1
,
16
M
⊙
,
75
%
of which are stars burning hydrogen in their core and the other
25
%
covering all other evolved stages. We close with a recommendation how to combine various methods to arrive at a “mass-ladder” for stars.
Three endophytic fungi isolated from
(Less.) G. Sancho (Asteraceae) were cultivated using the one strain many compounds (OSMAC) strategy to evaluate the production of griseofulvin derivatives. ...Extracts obtained were analyzed by HPLC-MS/MS and the chromatographic and spectrometric data used to elaborate a feature-based molecular network (FBMN) through the GNPS platform. This approach allowed the observation of differences such as medium-specific and strain-specific production of griseofulvin derivatives and variations of cytotoxic activity in most extracts. To evaluate the efficiency of the OSMAC approach allied with FBMN analysis in the prospection of compounds of biotechnological interest, griseofulvin and 7-dechlorogriseofulvin were isolated, and the relative concentrations were estimated in all culture media using HPLC-UV, allowing for the inference of the best strain-medium combinations to maximize its production. Malt extract-peptone broth and Wickerham broth media produced the highest concentrations of both secondary metabolites.
The current investigation assessed a) the performance of the FOCUS ADHD mobile health application (App) in increasing pharmacological treatment adherence and improving patients' knowledge of ...attention-deficit/hyperactivity disorder (ADHD) and b) the impact of implementing a financial incentive for using the App (i.e., a discount on medication).
In a randomized, blind, parallel-group clinical trial, 73 adults diagnosed with ADHD were allocated into three groups for 3 months: a) Pharmacological treatment as usual (TAU); b) TAU and the App (App Group); and c) TAU and the App + a commercial discount on the purchase of medication prescribed for ADHD treatment (App + Discount Group).
There was no significant difference in mean treatment adherence between groups, assessed as a medication possession ratio (MPR). However, the App + Discount Group exhibited greater medication intake registrations compared with the App Group during the initial phase of the trial. The financial discount also produced a 100% App adoption rate. App use did not increase ADHD knowledge, though knowledge scores were high at baseline. The usability and quality of the App were rated favorably.
The FOCUS ADHD App achieved a high adoption rate and positive evaluations by users. Use of the App did not increase adherence to treatment as measured by MPR, but, for App users, the addition of a financial incentive to use the App produced an increase in treatment adherence in terms of medication intake registrations. The present results offer encouraging data for combining incentives with mobile digital health solutions to positively impact treatment adherence in ADHD.
The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed ...to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial DNA (mtDNA) and 10 nuclear microsatellites loci. We analyzed 147 sequences of mtDNA control region and genotyped 111 individuals of South American sea lion for 10 microsatellite loci, representing six populations (Peru, Northern Chile, Southern Chile, Uruguay (Brazil), Argentina and Falkland (Malvinas) Islands) and covering the entire distribution of the species. The mtDNA phylogeny shows that haplotypes from the two oceans comprise two very divergent clades as observed in previous studies, suggesting a long period (>1 million years) of low inter-oceanic female gene flow. Bayesian analysis of bi-parental genetic diversity supports significant (but less pronounced than mitochondrial) genetic structure between Pacific and Atlantic populations, although also suggested some inter-oceanic gene flow mediated by males. Higher male migration rates were found in the intra-oceanic population comparisons, supporting very high female philopatry in the species. Demographic analyses showed that populations from both oceans went through a large population expansion ~10,000 years ago, suggesting a very similar influence of historical environmental factors, such as the last glacial cycle, on both regions. Our results support the proposition that the Pacific and Atlantic populations of the South American sea lion should be considered distinct evolutionarily significant units, with at least two managements units in each ocean.
In the present paper, we are concerned with the semilinear viscoelastic wave equation in an inhomogeneous medium Ω subject to two localized dampings. The first one is of the type viscoelastic and is ...distributed around a neighborhood ω of the boundary according to the Geometric Control Condition. The second one is a frictional damping and we consider it hurting the geometric condition of control. We show that the energy of the wave equation goes uniformly and exponentially to zero for all initial data of finite energy taken in bounded sets of finite energy phase-space.
Secretion of membrane-limited vesicles, collectively termed extracellular vesicles (EVs), is an important biological process of both eukaryotic and prokaryotic cells. This process has been observed ...in bacteria, but remains to be better characterized at high resolution in cyanobacteria. In the present work, we address the release of EVs by
(CYRF-01), a filamentous bloom-forming cyanobacterium, exposed to environmental stressors. First, non-axenic cultures of
(CYRF-01) were exposed to ultraviolet radiation (UVA + UVB) over a 6 h period, which is known to induce structural damage to this species. Second,
was co-cultured in interaction with another cyanobacterium species,
(MIRF-01), over a 24 h period. After the incubation times, cell density and viability were analyzed, and samples were processed for transmission electron microscopy (TEM). Our ultrastructural analyses revealed that
constitutively releases EVs from the outer membrane during its normal growth and amplifies such ability in response to environmental stressors. Both situations induced significant formation of outer membrane vesicles (OMVs) by
compared to control cells. Quantitative TEM revealed an increase of 48% (UV) and 60% (interaction) in the OMV numbers compared to control groups. Considering all groups, the OMVs ranged in size from 20 to 300 nm in diameter, with most OMVs showing diameters between 20 and 140 nm. Additionally, we detected that OMV formation is accompanied by phosphatidylserine exposure, a molecular event also observed in EV-secreting eukaryotic cells. Altogether, we identified for the first time that
has the competence to secrete OMVs and that under different stress situations the genesis of these vesicles is increased. The amplified ability of cyanobacteria to release OMVs may be associated with adaptive responses to changes in environmental conditions and interspecies cell communication.
Rotational Profiler provides an analytical algorithm to compute sets of classical torsional dihedral parameters by fitting an empirical energy profile to a reference one that can be obtained ...experimentally or by quantum-mechanical methods. The resulting profiles are compatible with the functional forms in the most widely used biomolecular force fields (e.g., GROMOS, AMBER, OPLS, and CHARMM). The linear least-squares regression method is used to generate sets of parameters that best satisfy the fitting. Rotational Profiler is free to use, analytical, and force field/package independent. The formalism is herein described, and its usage, in an interactive and automated manner, is made available as a Web server at http://rotprof.lncc.br.
The conventional cutting tools used for machining titanium alloys normally experience rapid tool wear, and it is generally difficult to achieve a cutting speed over 60 m/min. In this paper, a ...comprehensive study on improving the machining of Ti-6Al-4V alloy is presented, focusing on high-speed end milling at 100 m/min. Three different AlCrN PVD-coated cemented carbide tools were employed over cemented solid carbide endmills. The study aimed to understand the factors influencing tool performance and, particularly, the uncommon tool wear behavior characterized by chipping on the rake face. The research methodology involves a detailed investigation of coating properties, mechanical characteristics, surface defects, and tool edge geometries. Mechanical properties were measured to assess the resistance to plastic deformation and impact fatigue fracture resistance. Surface defects were meticulously observed, and tool edge geometries were evaluated through optical microscopies. These analyses uncover the key factors contributing to the best tool performance, notably the resistance to plastic deformation (H3/E2 ratio), impact fatigue fracture resistance, and maintaining uniform tool edge geometries. The results of this study reveal that the moderate stress C3 coating outperformed the other two coatings, exhibiting a 1.5-times-longer tool life, a relatively stable cutting force curve, and favorable friction conditions in the cutting zone.
Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and ...membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment. An overall cationic surface of the dimer assures enhanced interactions with negatively charged membranes. An extensive set of biophysical data allowed us to establish structure-function correlations with antimicrobial assays against Gram-positive and Gram-negative bacteria. Although both peptides present considerable antimicrobial activity, the dimer is significantly more effective in both antibacterial and membrane biophysical assays.
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