1,133 research outputs found
Sodium Doped LaMnO3 Thin Films: Influence of Substrate and Thickness on Physical Properties
In this paper we report the results about the synthesis and characterization
of optimally doped La1-xNaxMnO3 thin films grown onto SrTiO3 (100), NdGaO3
(100) and NdGaO3 (110) for thickness ranging from 11 to 82 nm. The effect of
substrate nature and orientation, film thickness and annealing procedure was
investigated in order to optimize their magnetoresistance (MR). We obtained
very smooth films displaying MR values greater than 70%, near to room
temperature.Comment: 31 pages, 9 figures Final version to appear in J. Phys. Chem.
Local Complexity of Delone Sets and Crystallinity
This paper characterizes when a Delone set X is an ideal crystal in terms of
restrictions on the number of its local patches of a given size or on the
hetereogeneity of their distribution. Let N(T) count the number of
translation-inequivalent patches of radius T in X and let M(T) be the minimum
radius such that every closed ball of radius M(T) contains the center of a
patch of every one of these kinds. We show that for each of these functions
there is a `gap in the spectrum' of possible growth rates between being bounded
and having linear growth, and that having linear growth is equivalent to X
being an ideal crystal. Explicitly, for N(T), if R is the covering radius of X
then either N(T) is bounded or N(T) >= T/2R for all T>0. The constant 1/2R in
this bound is best possible in all dimensions. For M(T), either M(T) is bounded
or M(T) >= T/3 for all T>0. Examples show that the constant 1/3 in this bound
cannot be replaced by any number exceeding 1/2. We also show that every
aperiodic Delone set X has M(T) >= c(n)T for all T>0, for a certain constant
c(n) which depends on the dimension n of X and is greater than 1/3 when n > 1.Comment: 26 pages. Uses latexsym and amsfonts package
Enumerating Abelian Returns to Prefixes of Sturmian Words
We follow the works of Puzynina and Zamboni, and Rigo et al. on abelian
returns in Sturmian words. We determine the cardinality of the set
of abelian returns of all prefixes of a Sturmian word in
terms of the coefficients of the continued fraction of the slope, dependingly
on the intercept. We provide a simple algorithm for finding the set
and we determine it for the characteristic Sturmian words.Comment: 19page
Microvascular damage evaluation in systemic sclerosis : the role of nailfold videocapillaroscopy and laser techniques
Microvascular damage and a decrease in peripheral blood perfusion are typical features of systemic sclerosis (SSc) with serious clinical implications, not only for a very early diagnosis, but also for disease progression. Nailfold videocapillaroscopy is a validated and safe imaging technique able to detect peripheral capillary morphology, as well as to classify and to score any nailfold abnormalities into different microangiopathy patterns.
Capillaroscopic analysis is now included in the ACR/EULAR classification criteria for SSc.
The decrease in peripheral blood perfusion is usually associated with microvascular damage in SSc, which may be studied by different methods. Several of these make use of safe laser technologies.
This paper focuses on these new clinical aspects to assess SSc microvascular impairment
Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung
Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation
Whither Capitalism? Financial externalities and crisis
As with global warming, so with financial crises – externalities have a lot to answer for. We
look at three of them. First the financial accelerator due to ‘fire sales’ of collateral assets -- a
form of pecuniary externality that leads to liquidity being undervalued. Second the ‘risk-
shifting’ behaviour of highly-levered financial institutions who keep the upside of risky
investment while passing the downside to others thanks to limited liability. Finally, the
network externality where the structure of the financial industry helps propagate shocks
around the system unless this is checked by some form of circuit breaker, or ‘ring-fence’.
The contrast between crisis-induced Great Recession and its aftermath of slow growth in the
West and the rapid - and (so far) sustained - growth in the East suggests that successful
economic progress may depend on how well these externalities are managed
Heparan sulfate and heparin interactions with proteins.
Heparan sulfate (HS) polysaccharides are ubiquitous components of the cell surface and extracellular matrix of all multicellular animals, whereas heparin is present within mast cells and can be viewed as a more sulfated, tissuespecific, HS variant. HS and heparin regulate biological processes through interactions with a large repertoire of proteins. Owing to these interactions
and diverse effects observed during in vitro, ex vivo and in vivo experiments, manifold biological/pharmacological activities have been attributed to them. The properties that have been thought to bestow protein binding and
biological activity upon HS and heparin vary from high levels of sequence specificity to a dependence on charge. In contrast to these opposing opinions, we will argue that the evidence supports both a level of redundancy and a
degree of selectivity in the structure–activity relationship. The relationship between this apparent redundancy, the multi-dentate nature of heparin and HS polysaccharide chains, their involvement in protein networks and the multiple binding sites on proteins, each possessing different properties, will also be considered. Finally, the role of cations in modulating HS/heparin activity will be reviewed and some of the implications for structure–activity relationships and regulation will be discussed
Colloquium: Mechanical formalisms for tissue dynamics
The understanding of morphogenesis in living organisms has been renewed by
tremendous progressin experimental techniques that provide access to
cell-scale, quantitative information both on theshapes of cells within tissues
and on the genes being expressed. This information suggests that
ourunderstanding of the respective contributions of gene expression and
mechanics, and of their crucialentanglement, will soon leap forward.
Biomechanics increasingly benefits from models, which assistthe design and
interpretation of experiments, point out the main ingredients and assumptions,
andultimately lead to predictions. The newly accessible local information thus
calls for a reflectionon how to select suitable classes of mechanical models.
We review both mechanical ingredientssuggested by the current knowledge of
tissue behaviour, and modelling methods that can helpgenerate a rheological
diagram or a constitutive equation. We distinguish cell scale ("intra-cell")and
tissue scale ("inter-cell") contributions. We recall the mathematical framework
developpedfor continuum materials and explain how to transform a constitutive
equation into a set of partialdifferential equations amenable to numerical
resolution. We show that when plastic behaviour isrelevant, the dissipation
function formalism appears appropriate to generate constitutive equations;its
variational nature facilitates numerical implementation, and we discuss
adaptations needed in thecase of large deformations. The present article
gathers theoretical methods that can readily enhancethe significance of the
data to be extracted from recent or future high throughput
biomechanicalexperiments.Comment: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few
corrections to the published version, all in Appendix D.2 devoted to large
deformation
Coexistence of osteopoikilosis with seronegative spondyloarthritis and Raynaud's phenomenon: first case report with evaluation of the nailfold capillary bed and literature review.
Osteopoikilosis (OPK) is a rare autosomal dominant bone disorder characterized by numerous hyperostotic areas that tend to localize in periarticular osseous regions. It is usually asymptomatic and is often diagnosed incidentally during X-rays. OPK may be an isolated finding or associated with other pathologies, e.g. skin manifestations, rheumatic and/or skeletal disorders. We report a literature review and, for the first time, the coexistence of OPK with seronegative spondyloarthritis and Raynaud's phenomenon in a 48-year old female. To the best of our knowledge, this is the first case of OPK studied by videocapillaroscopy, demonstrating the absence of specific microvascular abnormalities of nailfold capillaries
Observationally based analysis of land–atmosphere coupling
Abstract. The temporal variance of soil moisture, vegetation and evapotranspiration over land has been recognized to be strongly connected to the temporal variance of precipitation. However, the feedbacks and couplings between these variables are still not well understood and quantified. Furthermore, soil moisture and vegetation processes are associated with a memory and therefore they may have important implications for predictability. In this study we apply a generalized linear method, specifically designed to assess the reciprocal forcing between connected fields, to the latest available observational data sets of global precipitation, evapotranspiration, vegetation and soil moisture content. For the first time a long global observational data set is used to investigate the spatial and temporal land variability and to characterize the relationships and feedbacks between land and precipitation. The variables considered show a significant coupling among each other. The analysis of the response of precipitation to soil moisture evidences a robust coupling between these two variables. In particular, the first two modes of variability in the precipitation forced by soil moisture appear to have a strong link with volcanic eruptions and El Niño–Southern Oscillation (ENSO) cycles, respectively, and these links are modulated by the effects of evapotranspiration and vegetation. It is suggested that vegetation state and soil moisture provide a biophysical memory of ENSO and major volcanic eruptions, revealed through delayed feedbacks on rainfall patterns. The third mode of variability reveals a trend very similar to the trend of the inter-hemispheric contrast in sea surface temperature (SST) and appears to be connected to greening/browning trends of vegetation over the last three decades
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