98 research outputs found
Selenoprotein gene expression in an intestinal cell line during selenium depletion: a macroarray approach indicates effects on SelW and glutathione peroxidise 1.
The micronutrient selenium (Se) is incoprprated into a renage of selenoproteins involved in numerous biochemical processes within the body
Molecular Weight Dependence of Spreading Rates of Ultrathin Polymeric Films
We study experimentally the molecular weight dependence of spreading
rates of molecularly thin precursor films, growing at the bottom of droplets of
polymer liquids. In accord with previous observations, we find that the radial
extension R(t) of the film grows with time as R(t) = (D_{exp} t)^{1/2}. Our
data substantiate the M-dependence of D_{exp}; we show that it follows D_{exp}
\sim M^{-\gamma}, where the exponent \gamma is dependent on the chemical
composition of the solid surface, determining its frictional properties with
respect to the molecular transport. In the specific case of hydrophilic
substrates, the frictional properties can be modified by the change of the
relative humidity (RH). We find that \gamma \approx 1 at low RH and tends to
zero when RH gets progressively increased. We propose simple theoretical
arguments which explain the observed behavior in the limits of low and high RH.Comment: 4 pages, 2 figures, to appear in PR
Theoretical and experimental activities on opacities for a good interpretation of seismic stellar probes
Opacity calculations are basic ingredients of stellar modelling. They play a
crucial role in the interpretation of acoustic modes detected by SoHO, COROT
and KEPLER. In this review we present our activities on both theoretical and
experimental sides. We show new calculations of opacity spectra and comparisons
between eight groups who produce opacity spectra calculations in the domain
where experiments are scheduled. Real differences are noticed with real
astrophysical consequences when one extends helioseismology to cluster studies
of different compositions. Two cases are considered presently: (1) the solar
radiative zone and (2) the beta Cephei envelops. We describe how our
experiments are performed and new preliminary results on nickel obtained in the
campaign 2010 at LULI 2000 at Polytechnique.Comment: 6 pages, 4 figures, invited talk at SOHO2
Computational Study of Hippocampal-Septal Theta Rhythm Changes Due to Beta-Amyloid-Altered Ionic Channels
Electroencephagraphy (EEG) of many dementia patients has been characterized by an increase in low frequency field potential oscillations. One of the characteristics of early stage Alzheimer’s disease (AD) is an increase in theta band power (4–7 Hz). However, the mechanism(s) underlying the changes in theta oscillations are still unclear. To address this issue, we investigate the theta band power changes associated with β-Amyloid (Aβ) peptide (one of the main markers of AD) using a computational model, and by mediating the toxicity of hippocampal pyramidal neurons. We use an established biophysical hippocampal CA1-medial septum network model to evaluate four ionic channels in pyramidal neurons, which were demonstrated to be affected by Aβ. They are the L-type Ca2+ channel, delayed rectifying K+ channel, A-type fast-inactivating K+ channel and large-conductance Ca2+-activated K+ channel. Our simulation results demonstrate that only the Aβ inhibited A-type fast-inactivating K+ channel can induce an increase in hippocampo-septal theta band power, while the other channels do not affect theta rhythm. We further deduce that this increased theta band power is due to enhanced synchrony of the pyramidal neurons. Our research may elucidate potential biomarkers and therapeutics for AD. Further investigation will be helpful for better understanding of AD-induced theta rhythm abnormalities and associated cognitive deficits
Radiative properties of stellar plasmas and open challenges
The lifetime of solar-like stars, the envelope structure of more massive
stars, and stellar acoustic frequencies largely depend on the radiative
properties of the stellar plasma. Up to now, these complex quantities have been
estimated only theoretically. The development of the powerful tools of helio-
and astero- seismology has made it possible to gain insights on the interiors
of stars. Consequently, increased emphasis is now placed on knowledge of the
monochromatic opacity coefficients. Here we review how these radiative
properties play a role, and where they are most important. We then concentrate
specifically on the envelopes of Cephei variable stars. We discuss the
dispersion of eight different theoretical estimates of the monochromatic
opacity spectrum and the challenges we need to face to check these calculations
experimentally.Comment: 6 pages, 5 figures, in press (conference HEDLA 2010
Primary breast lymphoma: Patient profile, outcome and prognostic factors. A multicentre Rare Cancer Network study
BACKGROUND: To asses the clinical profile, treatment outcome and prognostic factors in primary breast lymphoma (PBL). METHODS: Between 1970 and 2000, 84 consecutive patients with PBL were treated in 20 institutions of the Rare Cancer Network. Forty-six patients had Ann Arbor stage IE, 33 stage IIE, 1 stage IIIE, 2 stage IVE and 2 an unknown stage. Twenty-one underwent a mastectomy, 39 conservative surgery and 23 biopsy; 51 received radiotherapy (RT) with (n = 37) or without (n = 14) chemotherapy. Median RT dose was 40 Gy (range 12-55 Gy). RESULTS: Ten (12%) patients progressed locally and 43 (55%) had a systemic relapse. Central nervous system (CNS) was the site of relapse in 12 (14%) cases. The 5-yr overall survival, lymphoma-specific survival, disease-free survival and local control rates were 53%, 59%, 41% and 87% respectively. In the univariate analyses, favorable prognostic factors were early stage, conservative surgery, RT administration and combined modality treatment. Multivariate analysis showed that early stage and the use of RT were favorable prognostic factors. CONCLUSION: The outcome of PBL is fair. Local control is excellent with RT or combined modality treatment but systemic relapses, including that in the CNS, occurs frequently
Optimization of interneuron function by direct coupling of cell migration and axonal targeting
Neural circuit assembly relies on the precise synchronization of developmental processes, such as cell migration and axon targeting, but the cell-autonomous mechanisms coordinating these events remain largely unknown. Here we found that different classes of interneurons use distinct routes of migration to reach the embryonic cerebral cortex. Somatostatin-expressing interneurons that migrate through the marginal zone develop into Martinotti cells, one of the most distinctive classes of cortical interneurons. For these cells, migration through the marginal zone is linked to the development of their characteristic layer 1 axonal arborization. Altering the normal migratory route of Martinotti cells by conditional deletion of Mafb—a gene that is preferentially expressed by these cells—cell-autonomously disrupts axonal development and impairs the function of these cells in vivo. Our results suggest that migration and axon targeting programs are coupled to optimize the assembly of inhibitory circuits in the cerebral cortex
A review of camera trapping for conservation behaviour research
An understanding of animal behaviour is important if conservation initiatives
are to be effective. However, quantifying the behaviour of wild animals presents
significant challenges. Remote-sensing camera traps are becoming increasingly
popular survey instruments that have been used to non-invasively study a variety
of animal behaviours, yielding key insights into behavioural repertoires.
They are well suited to ethological studies and provide considerable opportunities
for generating conservation-relevant behavioural data if novel and robust
methodological and analytical solutions can be developed. This paper reviews
the current state of camera-trap-based ethological studies, describes new and
emerging directions in camera-based conservation behaviour, and highlights a
number of limitations and considerations of particular relevance for camerabased
studies. Three promising areas of study are discussed: (1) documenting
anthropogenic impacts on behaviour; (2) incorporating behavioural responses
into management planning and (3) using behavioural indicators such as giving
up densities and daily activity patterns. We emphasize the importance of
reporting methodological details, utilizing emerging camera trap metadata standards
and central data repositories for facilitating reproducibility, comparison
and synthesis across studies. Behavioural studies using camera traps are in their
infancy; the full potential of the technology is as yet unrealized. Researchers are
encouraged to embrace conservation-driven hypotheses in order to meet future
challenges and improve the efficacy of conservation and management processes.The contribution of M.D. Wood was
supported by the TREE project (www.ceh.ac.
uk/TREE) funded by the Natural Environment
Research Council (NERC), Environment
Agency and Radioactive Waste Management
Limited. The contributions of C.M.V. Finlay
were supported by the Red Squirrels United
project (http://www.redsquirrelsunited.org.uk/)
funded by EU Life and Heritage Lottery Fund.http://zslpublications.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2056-3485am2017Centre for Wildlife Managemen
Epigenetics and developmental programming of welfare and production traits in farm animals
The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the ‘developmental origins of health and disease’ or ‘DOHaD’ hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems
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