251 research outputs found
How legal restrictions on abortion are harming women all over the world
. El ensayo destaca algunos de los últimos datos publicados sobre el aborto a nivel mundial, entre ellos el impacto del aborto inseguro, y subraya el daño provocado por las restricciones legales ya que aumentan la probabilidad de que el aborto sea inseguro. Comenta que Irlanda enfrenta una votación histórica sobre si reformar las leyes de aborto del país que se encuentran entre los más restrictivos de Europa. Actualmente, las mujeres en Irlanda que necesitan un aborto se ven obligadas a viajar al extranjero, generalmente Inglaterra, o pueden recurrir a la terminación clandestina de sus embarazos.https://www.telegraph.co.uk/news/2018/05/22/countries-ban-abortion-taking-lives-save-women-babies
Microrheology, stress fluctuations and active behavior of living cells
We report the first measurements of the intrinsic strain fluctuations of
living cells using a recently-developed tracer correlation technique along with
a theoretical framework for interpreting such data in heterogeneous media with
non-thermal driving. The fluctuations' spatial and temporal correlations
indicate that the cytoskeleton can be treated as a course-grained continuum
with power-law rheology, driven by a spatially random stress tensor field.
Combined with recent cell rheology results, our data imply that intracellular
stress fluctuations have a nearly power spectrum, as expected for
a continuum with a slowly evolving internal prestress.Comment: 4 pages, 2 figures, to appear in Phys. Rev. Let
Antioxidant enzymes in the developing lungs of egg-laying and metamorphosing vertebrates
© The Company of BiologistsThe activities of the pulmonary antioxidant enzymes (AOE), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase, increase in the final 10–20 % of gestation in the mammalian lung, to protect the lung from attack by increasing levels of reactive oxygen species at birth. Whether the increase occurs as a normal ‘preparation for birth’, i.e. by a genetically determined mechanism, or in response to increased levels of oxygen, i.e. in response to the environment, is not completely understood. We examined the activities of catalase, SOD and GPx in the developing lungs of two oviparous vertebrate species, the chicken (Gallus gallus) and an agamid lizard (Pogona vitticeps), and in a metamorphosing vertebrate, the anuran Limnodynastes terraereginae. During in ovo development embryos come into contact with higher levels of environmental oxygen, and at a much earlier stage of development, compared with the intrauterine development of mammals. Furthermore, in metamorphosing frogs, the lungs are inflated at an early stage to aid in buoyancy, although the gas-exchange function only develops much later upon final metamorphosis. Here, we hypothesise that the activity of the AOE will be elevated relatively much earlier during development in both oviparous and metamorphosing vertebrates. We also examined the effect of mild hypoxia (17 % oxygen) on the development of the pulmonary AOE in the chicken, to test the hypothesis that these enzymes are responsive to environmental oxygen. In the normoxic lung of both Gallus gallus and Pogona vitticeps, catalase and GPx activities were significantly increased in late incubation, whereas SOD activity decreased in late incubation. Catalase and SOD activities were virtually identical in hypoxic and normoxic embryos of the chicken, but GPx activity was significantly affected by hypoxia. In the developing frog, the activities of all enzymes were high at stage 30, demonstrating that the system is active before the lung displays any significant gas-exchange function. SOD and GPx activity did not increase further with development. Catalase activity increased after stage 40, presumably correlating with an increase in air-breathing. In summary, catalase expression in the two oviparous vertebrates appears to be completely under genetic control as the activity of this enzyme does not change in response to changes in oxygen tension. However, in tadpoles, catalase may be responsive to environmental oxygen. SOD also appears to follow a largely genetically determined program in all species. Under normoxic conditions, GPx appears to follow a genetically determined developmental pattern, but this enzyme demonstrated the largest capacity to respond to environmental oxygen fluctuations. In conclusion, it appears that the AOE are differentially regulated. Furthermore, the AOE in the different species appear to have evolved different levels of dependency on environmental variables. Finally, the late developmental increase in AOE activity seen in mammals is not as pronounced in oviparous and metamorphosing vertebrates.Adam P. Starrs, Sandra Orgeig, Christopher B. Daniels, Margaret Davies and Olga V. Lopatk
The Role of Solid Friction in the Sedimentation of Strongly Attractive Colloidal Gels
We study experimentally and theoretically the sedimentation of gels made of
strongly aggregated colloidal particles, focussing on the long time behavior,
when mechanical equilibrium is asymptotically reached. The asymptotic gel
height is found to vary linearly with the initial height, a finding in stark
contrast with a recent study on similar gels [Manley \textit{et al.} 2005
\textit{Phys. Rev. Lett.} \textbf{94} 218302]. We show that the asymptotic
compaction results from the balance between gravity pull, network elasticity,
and solid friction between the gel and the container walls. Based on these
ingredients, we propose a simple model to account for the dependence of the
height loss on the initial height and volume fraction. As a result of our
analysis, we show that the static friction coefficient between the gel and the
container walls strongly depends on volume fraction: the higher the volume
fraction, the weaker the solid friction. This nonintuitive behavior is
explained using simple scaling arguments.Comment: 13 pages, 5 figures. Submitted to JSTA
Optical microrheology using rotating laser-trapped particles
We demonstrate an optical system that can apply and accurately measure the
torque exerted by the trapping beam on a rotating birefringent probe particle.
This allows the viscosity and surface effects within liquid media to be
measured quantitatively on a micron-size scale using a trapped rotating
spherical probe particle. We use the system to measure the viscosity inside a
prototype cellular structure.Comment: 5 pages, 4 figures. v2: bibliographic details, minor text correction
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Predicting suicides after outpatient mental health visits in the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS).
The 2013 US Veterans Administration/Department of Defense Clinical Practice Guidelines (VA/DoD CPG) require comprehensive suicide risk assessments for VA/DoD patients with mental disorders but provide minimal guidance on how to carry out these assessments. Given that clinician-based assessments are not known to be strong predictors of suicide, we investigated whether a precision medicine model using administrative data after outpatient mental health specialty visits could be developed to predict suicides among outpatients. We focused on male nondeployed Regular US Army soldiers because they account for the vast majority of such suicides. Four machine learning classifiers (naive Bayes, random forests, support vector regression and elastic net penalized regression) were explored. Of the Army suicides in 2004-2009, 41.5% occurred among 12.0% of soldiers seen as outpatient by mental health specialists, with risk especially high within 26 weeks of visits. An elastic net classifier with 10-14 predictors optimized sensitivity (45.6% of suicide deaths occurring after the 15% of visits with highest predicted risk). Good model stability was found for a model using 2004-2007 data to predict 2008-2009 suicides, although stability decreased in a model using 2008-2009 data to predict 2010-2012 suicides. The 5% of visits with highest risk included only 0.1% of soldiers (1047.1 suicides/100 000 person-years in the 5 weeks after the visit). This is a high enough concentration of risk to have implications for targeting preventive interventions. An even better model might be developed in the future by including the enriched information on clinician-evaluated suicide risk mandated by the VA/DoD CPG to be recorded
Improved source localization with LIGO India
A global network of advanced gravitational wave interferometric detectors is
under construction. These detectors will offer an order of magnitude
improvement in sensitivity over the initial detectors and will usher in the era
of gravitational wave astronomy. In this paper, we evaluate the benefits of
relocating one of the advanced LIGO detectors to India.Comment: 7 pages, 3 figures, accepted for publication in proceedings of
ICGC2011 conference. Localization figures update
Developments in Performance Monitoring of Concrete Exposed to Extreme Environments.
The performance of the surface zone of concrete is acknowledged as a major factor governing the rate of deterioration of reinforced concrete structures because it provides the only barrier to the ingress of water containing dissolved ionic species such as chlorides, which ultimately initiate corrosion of the reinforcement. In situ monitoring of cover-zone concrete is therefore critical in attempting to make realistic predictions as to the in-service performance of the structure. To this end, this paper presents developments in a remote interrogation system to allow for continuous, real-time monitoring of the cover-zone concrete from an office setting. Use is made of a multi electrode array embedded within cover-zone concrete to acquire discretized electrical resistivity and temperature measurements, with both parameters monitored spatially and temporally. On-site instrumentation, which allows for the remote interrogation of concrete samples placed at a marine exposure site, is detailed together with data handling and processing procedures. Site measurements highlight the influence of temperature on electrical resistivity and an Arrhenius-based temperature correction protocol is developed using on-site measurements to standardize resistivity data to a reference temperature; this is an advancement over the use of laboratory-based procedures. The testing methodology and interrogation system represent a robust, low-cost, and high-value technique that could be deployed for intelligent monitoring of reinforced concrete structures
Respiratory Syncytial Virus Matrix Protein-Chromatin Association Is Key to Transcriptional Inhibition in Infected Cells
The morbidity and mortality caused by the globally prevalent human respiratory pathogen respiratory syncytial virus (RSV) approaches that world-wide of influenza. We previously demonstrated that the RSV matrix (M) protein shuttles, in signal-dependent fashion, between host cell nucleus and cytoplasm, and that this trafficking is central to RSV replication and assembly. Here we analyze in detail the nuclear role of M for the first time using a range of novel approaches, including quantitative analysis of de novo cell transcription in situ in the presence or absence of RSV infection or M ectopic expression, as well as in situ DNA binding. We show that M, dependent on amino acids 110–183, inhibits host cell transcription in RSV-infected cells as well as cells transfected to express M, with a clear correlation between nuclear levels of M and the degree of transcriptional inhibition. Analysis of bacterially expressed M protein and derivatives thereof mutated in key residues within M’s RNA binding domain indicates that M can bind to DNA as well as RNA in a cell-free system. Parallel results for point-mutated M derivatives implicate arginine 170 and lysine 172, in contrast to other basic residues such as lysine 121 and 130, as critically important residues for inhibition of transcription and DNA binding both in situ and in vitro. Importantly, recombinant RSV carrying arginine 170/lysine 172 mutations shows attenuated infectivity in cultured cells and in an animal model, concomitant with altered inflammatory responses. These findings define an RSV M-chromatin interface critical for host transcriptional inhibition in infection, with important implications for anti-RSV therapeutic development
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