3,248 research outputs found
Positive lifestyle behaviours and emotional health factors are associated with low back pain resilience
Purpose: To evaluate the relationship between lifestyle behaviours, emotional health factors, and low back pain (LBP) resilience. Methods: This retrospective longitudinal study utilised 1,065 twins with a recent history of LBP from the Washington State Twin Registry. A lifestyle behaviour score was built using variables of body mass index, physical activity engagement, sleep quality, smoking status, and alcohol consumption. An emotional health score was built using variables of the absence of depressed mood, perceived stress, and active coping. The main outcome was LBP resilience, assessed as recovery (“bouncing back”), and sustainability (maintaining high levels of function despite LBP). Results: After adjusting for covariates, there was no relationship between the lifestyle behaviour score (OR 1.05, 95% CI 0.97–1.15, p = 0.218) and the emotional health score (OR 1.08, 95% CI 0.98–1.19, p = 0.142) with the likelihood of recovering from LBP. There was however, evidence of a positive association between the lifestyle behaviour score (β 0.20, 95% CI 0.04–0.36, p = 0.013), the emotional health score (β 0.22, 95% CI 0.00–0.43, p = 0.049), and greater levels of sustainability. These results were confirmed by a within-pair analysis (lifestyle behaviour score: β 1.79, 95% CI 0.05–3.53, p = 0.043) and (emotional health score: β 0.52, 95% CI 0.09–0.96, p = 0.021) adjusting for genetic and early shared environmental confounding. Conclusion: Findings from this study suggest that people who adopt optimal lifestyle behaviours and positive emotional factors are more likely to be resilient and maintain high levels of function despite suffering from LBP
Interactions between silica and titanium nanoparticles and oral and gastrointestinal epithelia: Consequences for inflammatory diseases and cancer
Engineered nanoparticles (NPs) composed of elements such as silica and titanium, smaller than 100 nm in diameter and their aggregates, are found in consumer products such as cosmetics, food, antimicrobials and drug delivery systems, and oral health products such as toothpaste and dental materials. They may also interact accidently with epithelial tissues in the intestines and oral cavity, where they can aggregate into larger particles and induce inflammation through pathways such as inflammasome activation. Persistent inflammation can lead to precancerous lesions. Both the particles and lesions are difficult to detect in biopsies, especially in clinical settings that screen large numbers of patients. As diagnosis of early stages of disease can be lifesaving, there is growing interest in better understanding interactions between NPs and epithelium and developing rapid imaging techniques that could detect foreign particles and markers of inflammation in epithelial tissues. NPs can be labelled with fluorescence or radioactive isotopes, but it is challenging to detect unlabeled NPs with conventional imaging techniques. Different current imaging techniques such as synchrotron radiation X-ray fluorescence spectroscopy are discussed here. Improvements in imaging techniques, coupled with the use of machine learning tools, are needed before diagnosis of particles in biopsies by automated imaging could move usefully into the clinic
Effect of band anisotropy on electronic structure of PbS, PbSe, and PbTe quantum dots
We have calculated the electronic structure of spherical PbS, PbSe, and PbTe quantum dots using a four-band envelope-function formalism that accounts for band anisotropy. By comparing our results with an analytical calculation that assumes a spherical approximation of the (k) over right arrow.(p) over right arrow Hamiltonian, we show that the effects of band anisotropy are more pronounced for the excited states and increase with the confinement. We also show how the same technique can be applied to ellipsoidal quantum dots.62117357736
Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey
Studies of Galactic chemical and dynamical evolution in the solar
neighborhood depend on the availability of precise atmospheric parameters
(Teff, [Fe/H] and log g) for solar-type stars. Many large-scale spectroscopic
surveys operate at low to moderate spectral resolution for efficiency in
observing large samples, which makes the stellar characterization difficult due
to the high degree of blending of spectral features. While most surveys use
spectral synthesis, in this work we employ an alternative method based on
spectral indices to determine the atmospheric parameters of a sample of nearby
FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving
power (R~12,000). We have developed three codes to automatically normalize the
observed spectra, measure the equivalent widths of the indices and, through the
comparison of those with values calculated with pre-determined calibrations,
derive the atmospheric parameters of the stars. The calibrations were built
using a sample of 309 stars with precise stellar parameters obtained from the
analysis of high-resolution FEROS spectra. A validation test of the method was
conducted with a sample of 30 MARVELS targets that also have reliable
atmospheric parameters from high-resolution spectroscopic analysis. Our
approach was able to recover the parameters within 80 K for Teff, 0.05 dex for
[Fe/H] and 0.15 dex for log g, values that are lower or equal to the typical
external uncertainties found between different high-resolution analyzes. An
additional test was performed with a subsample of 138 stars from the ELODIE
stellar library and the literature atmospheric parameters were recovered within
125 K for Teff, 0.10 dex for [Fe/H] and 0.29 dex for log g. These results show
that the spectral indices are a competitive tool to characterize stars with the
intermediate resolution spectra.Comment: Accepted for publication in AJ. Abstract edited to comply with arXiv
standards regarding the number of character
The role of physical frailty independent components on increased disabilities in institutionalized older women
The purpose of this study was to identify the independent components of physical frailty that most influence disability indicators in institutionalized older women. A cross-sectional study with 319 participants (81.96±7.89 years old) was performed. Disability was assessed through dynamic and static balance tests, activities of daily life and falls risk screen. Fried physical frailty protocol was used to access physical frailty. The frail subgroup displayed the weakest results for all disability indicators (p < 0.05). Regression analysis showed that in the two models tested, low physical activity levels and slowness were the physical frailty independent components that better associated with the disability indicators. More studies with larger samples will help to better understand the independent relationship of each physical frailty component with disability outcomes and assist to design a co-adjuvant treatment to reverse physical frailty
Challenges in integrating Escherichia coli molecular biology data
One key challenge in Systems Biology is to provide mechanisms to collect and integrate the necessary data to be
able to meet multiple analysis requirements. Typically, biological contents are scattered over multiple data sources
and there is no easy way of comparing heterogeneous data contents. This work discusses ongoing standardisation
and interoperability efforts and exposes integration challenges for the model organism Escherichia coli K-12. The
goal is to analyse the major obstacles faced by integration processes, suggest ways to systematically identify them,
and whenever possible, propose solutions or means to assistmanual curation. Integration of gene, protein and compound
data was evaluated by performing comparisons over EcoCyc, KEGG, BRENDA, ChEBI, Entrez Gene and
UniProt contents. Cross-links, a number of standard nomenclatures and name information supported the comparisons.
Except for the gene integration scenario, in no other scenario an element of integration performed well
enough to support the process by itself. Indeed, both the integration of enzyme and compound records imply considerable
curation. Results evidenced that, even for a well-studied model organism, source contents are still far
from being as standardized as it would be desired and metadata varies considerably from source to source. Before
designing any data integration pipeline, researchers should decide on the sources that best fit the purpose of analysis
and be aware of existing conflicts/inconsistencies to be able to intervene in their resolution. Moreover, they should
be aware of the limits of automatic integration such that they can define the extent of necessary manual curation
for each application.Portuguese FCT funded
MIT-Portugal Program in Bioengineering
(MIT-Pt/BS-BB/0082/2008); PhD grant from
FCT (ref. SFRH/BD/22863/2005) to S.
The GATA1s isoform is normally down-regulated during terminal haematopoietic differentiation and over-expression leads to failure to repress MYB, CCND2 and SKI during erythroid differentiation of K562 cells
Background: Although GATA1 is one of the most extensively studied haematopoietic transcription factors little is currently known about the physiological functions of its naturally occurring isoforms GATA1s and GATA1FL in humans—particularly whether the isoforms have distinct roles in different lineages and whether they have non-redundant roles in haematopoietic differentiation. As well as being of general interest to understanding of haematopoiesis, GATA1 isoform biology is important for children with Down syndrome associated acute megakaryoblastic leukaemia (DS-AMKL) where GATA1FL mutations are an essential driver for disease pathogenesis.
<p/>Methods: Human primary cells and cell lines were analyzed using GATA1 isoform specific PCR. K562 cells expressing GATA1s or GATA1FL transgenes were used to model the effects of the two isoforms on in vitro haematopoietic differentiation.
<p/>Results: We found no evidence for lineage specific use of GATA1 isoforms; however GATA1s transcripts, but not GATA1FL transcripts, are down-regulated during in vitro induction of terminal megakaryocytic and erythroid differentiation in the cell line K562. In addition, transgenic K562-GATA1s and K562-GATA1FL cells have distinct gene expression profiles both in steady state and during terminal erythroid differentiation, with GATA1s expression characterised by lack of repression of MYB, CCND2 and SKI.
<p/>Conclusions: These findings support the theory that the GATA1s isoform plays a role in the maintenance of proliferative multipotent megakaryocyte-erythroid precursor cells and must be down-regulated prior to terminal differentiation. In addition our data suggest that SKI may be a potential therapeutic target for the treatment of children with DS-AMKL
A Cautionary Tale: MARVELS Brown Dwarf Candidate Reveals Itself To Be A Very Long Period, Highly Eccentric Spectroscopic Stellar Binary
We report the discovery of a highly eccentric, double-lined spectroscopic
binary star system (TYC 3010-1494-1), comprising two solar-type stars that we
had initially identified as a single star with a brown dwarf companion. At the
moderate resolving power of the MARVELS spectrograph and the spectrographs used
for subsequent radial-velocity (RV) measurements (R ~ <30,000), this particular
stellar binary mimics a single-lined binary with an RV signal that would be
induced by a brown dwarf companion (Msin(i)~50 M_Jup) to a solar-type primary.
At least three properties of this system allow it to masquerade as a single
star with a very low-mass companion: its large eccentricity (e~0.8), its
relatively long period (P~238 days), and the approximately perpendicular
orientation of the semi-major axis with respect to the line of sight (omega~189
degrees). As a result of these properties, for ~95% of the orbit the two sets
of stellar spectral lines are completely blended, and the RV measurements based
on centroiding on the apparently single-lined spectrum is very well fit by an
orbit solution indicative of a brown dwarf companion on a more circular orbit
(e~0.3). Only during the ~5% of the orbit near periastron passage does the
true, double-lined nature and large RV amplitude of ~15 km/s reveal itself. The
discovery of this binary system is an important lesson for RV surveys searching
for substellar companions; at a given resolution and observing cadence, a
survey will be susceptible to these kinds of astrophysical false positives for
a range of orbital parameters. Finally, for surveys like MARVELS that lack the
resolution for a useful line bisector analysis, it is imperative to monitor the
peak of the cross-correlation function for suspicious changes in width or
shape, so that such false positives can be flagged during the candidate vetting
process.Comment: 16 pages, 11 figures, 6 table
TRAUMATISMO DENTÁRIO COM SUCESSO NO REIMPLANTE: UM RELATO DE CASO.
Introdução: Avulsão dentária está relacionada com causas extrínsecas, como acidentes e intrínsecas, como a cárie. Tendo maior incidência em crianças de 7-12 anos, sendo os incisivos centrais superiores os dentes mais acometido
Very Low Mass Stellar and Substellar Companions to Solar-Like Stars From MARVELS V: A Low Eccentricity Brown Dwarf from the Driest Part of the Desert, MARVELS-6b
We describe the discovery of a likely brown dwarf (BD) companion with a
minimum mass of 31.7 +/- 2.0 M_Jup to GSC 03546-01452 from the MARVELS radial
velocity survey, which we designate as MARVELS-6b. For reasonable priors, our
analysis gives a probability of 72% that MARVELS-6b has a mass below the
hydrogen-burning limit of 0.072 M_Sun, and thus it is a high-confidence BD
companion. It has a moderately long orbital period of 47.8929 +0.0063/-0.0062
days with a low eccentricty of 0.1442 +0.0078/-0.0073, and a semi-amplitude of
1644 +12/-13 m/s. Moderate resolution spectroscopy of the host star has
determined the following parameters: T_eff = 5598 +/- 63, log g = 4.44 +/-
0.17, and [Fe/H] = +0.40 +/- 0.09. Based upon these measurements, GSC
03546-01452 has a probable mass and radius of M_star = 1.11 +/- 0.11 M_Sun and
R_star = 1.06 +/- 0.23 R_Sun with an age consistent with less than ~6 Gyr at a
distance of 219 +/- 21 pc from the Sun. Although MARVELS-6b is not observed to
transit, we cannot definitively rule out a transiting configuration based on
our observations. There is a visual companion detected with Lucky Imaging at
7.7 arcsec from the host star, but our analysis shows that it is not bound to
this system. The minimum mass of MARVELS-6b exists at the minimum of the mass
functions for both stars and planets, making this a rare object even compared
to other BDs.Comment: 15 pages, 15 figures, 5 tables. Accepted for publication in The
Astronomical Journa
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