115 research outputs found
Exploring pressure effects on metallic nanoparticles and surrounding media through plasmonic sensing
The sensing capabilities of gold nanorods under high-pressure conditions were investigated in methanol-ethanol mixtures (up to 13 GPa) and in water (up to 9 GPa) through their optical extinction. The longitudinal SPR band of AuNR exhibits a redshift with pressure which is the result of two main competing effects: compression of the conduction electrons which increases the bulk plasma frequency (blueshift) and increase in the solvent density (redshift). The variation in de SPR peak wavelength allows us to estimate the bulk modulus of the gold nanoparticles with a precision of 10 % and to obtain analytical functions providing the pressure dependence of the refractive index of water in three phases: liquid, ice VI and ice VII. Furthermore, the SPR band shows abrupt jumps at the liquid to ice phase VI and ice phase VII transitions, which are in accordance with the first-order character of these transitions.Financial support from Project PGC2018-101464-B-I00 (FEDER) and MALTA-Consolider Team (RED2018-102612-T) of the Ministerio de Ciencia, Innovación y Universidades is acknowledged
Quantifying the overall added value of dynamical downscaling and the contribution from different spatial scales
This study evaluates the added value in the representation of surface climate variables from\ud
an ensemble of regional climate model (RCM) simulations by comparing the relative skill of the RCM\ud
simulations and their driving data over a wide range of RCM experimental setups and climate statistics.\ud
The methodology is specifically designed to compare results across different variables and metrics, and it\ud
incorporates a rigorous approach to separate the added value occurring at different spatial scales. Results\ud
show that the RCMs’ added value strongly depends on the type of driving data, the climate variable, and the\ud
region of interest but depends rather weakly on the choice of the statistical measure, the season, and the\ud
RCM physical configuration. Decomposing climate statistics according to different spatial scales shows that\ud
improvements are coming from the small scales when considering the representation of spatial patterns,\ud
but from the large-scale contribution in the case of absolute values. Our results also show that a large part\ud
of the added value can be attained using some simple postprocessing methods
Powellsnakes II: a fast Bayesian approach to discrete object detection in multi-frequency astronomical data sets
Powellsnakes is a Bayesian algorithm for detecting compact objects embedded
in a diffuse background, and was selected and successfully employed by the
Planck consortium in the production of its first public deliverable: the Early
Release Compact Source Catalogue (ERCSC). We present the critical foundations
and main directions of further development of PwS, which extend it in terms of
formal correctness and the optimal use of all the available information in a
consistent unified framework, where no distinction is made between point
sources (unresolved objects), SZ clusters, single or multi-channel detection.
An emphasis is placed on the necessity of a multi-frequency, multi-model
detection algorithm in order to achieve optimality
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Loss of CD147 results in impaired epithelial cell differentiation and malformation of the meibomian gland
Meibomian gland dysfunction is a leading cause of ocular surface disease. However, little is known about the regulatory processes that control the development and maintenance of this sebaceous gland. Here, we identify a novel function for CD147, a transmembrane protein that promotes tissue remodeling through induction of matrix metalloproteinases, in regulating meibocyte differentiation and activity. We found that CD147 localized along basal cells and within discrete membrane domains of differentiated meibocytes in glandular acini containing gelatinolytic activity. Induction of meibocyte differentiation in vitro promoted CD147 clustering and MMP9 secretion, whereas RNAi-mediated abrogation of CD147 impaired MMP9 secretion, concomitant with a reduction in the number of proliferative cells and cytoplasmic lipids. Meibomian glands of CD147 knockout mice had a lower number of acini in both the superior and inferior tarsal plates of the eyelids, and were characterized by loss of lipid-filled meibocytes compared with control mice. Together, our data provide evidence showing that gelatinolytic activity in meibocytes is dependent on CD147, and supports a role for CD147 in maintaining the normal development and function of the meibomian gland
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Loss of CD147 results in impaired epithelial cell differentiation and malformation of the meibomian gland
Meibomian gland dysfunction is a leading cause of ocular surface disease. However, little is known about the regulatory processes that control the development and maintenance of this sebaceous gland. Here, we identify a novel function for CD147, a transmembrane protein that promotes tissue remodeling through induction of matrix metalloproteinases, in regulating meibocyte differentiation and activity. We found that CD147 localized along basal cells and within discrete membrane domains of differentiated meibocytes in glandular acini containing gelatinolytic activity. Induction of meibocyte differentiation in vitro promoted CD147 clustering and MMP9 secretion, whereas RNAi-mediated abrogation of CD147 impaired MMP9 secretion, concomitant with a reduction in the number of proliferative cells and cytoplasmic lipids. Meibomian glands of CD147 knockout mice had a lower number of acini in both the superior and inferior tarsal plates of the eyelids, and were characterized by loss of lipid-filled meibocytes compared with control mice. Together, our data provide evidence showing that gelatinolytic activity in meibocytes is dependent on CD147, and supports a role for CD147 in maintaining the normal development and function of the meibomian gland
Predictions for high-frequency radio surveys of extragalactic sources
We present detailed predictions of the contributions of the various source
populations to the counts at frequencies of tens of GHz. New evolutionary
models are worked out for flat-spectrum radio quasars, BL Lac objects, and
steep-spectrum sources. Source populations characterized by spectra peaking at
high radio frequencies, such as extreme GPS sources, ADAF/ADIOS sources and
early phases of gamma-ray burst afterglows are also dealt with. The counts of
different populations of star-forming galaxies (normal spirals, starbursts,
high-z galaxies detected by SCUBA and MAMBO surveys, interpreted as
proto-spheroidal galaxies) are estimated taking into account both synchrotron
and free-free emission, and dust re-radiation. Our analysis is completed by
updated counts of Sunyaev-Zeldovich effects in clusters of galaxies and by a
preliminary estimate of galactic-scale Sunyaev-Zeldovich signals associated to
proto-galactic plasma.Comment: 12 pages, 14 figures, to be published in A&
Pressure-induced spin transition and site-selective metallization in CoCl2
The interplay between spin states and metallization in compressed CoCl 2 is investigated by combining diffraction, resistivity and spectroscopy techniques under high-pressure conditions and ab-initio calculations. A pressure-induced metallization along with a Co 2+ high-spin (S = 3/2) to low-spin (S = 1/2) crossover transition is observed at high pressure near 70 GPa. This metallization process, which is associated with the p-d charge-transfer band gap closure, maintains the localization of 3d electrons around Co 2+ , demonstrating that metallization and localized Co 2+ -3d low-spin magnetism can coexist prior to the full 3d-electron delocalization (Mott-Hubbard d-d breakdown) at pressures greater than 180 GPa.Financial support from the Spanish Ministerio de Economıa y Competitividad (Project No. MAT2015-69508-P,
MAT2016-80438-P) and MALTA-CONSOLIDER (Ref. No. MAT2015-71070-REDC) is acknowledged
Planck early results. XIII. Statistical properties of extragalactic radio sources in the Planck Early Release Compact Source Catalogue
The data reported in Planck?s Early Release Compact Source Catalogue (ERCSC) are exploited to measure the number counts (dN/dS) of extragalactic radio sources at 30, 44, 70, 100, 143 and 217 GHz. Due to the full-sky nature of the catalogue, this measurement extends to the rarest and brightest sources in the sky. At lower frequencies (30, 44, and 70 GHz) our counts are in very good agreement with estimates based on WMAP data, being somewhat deeper at 30 and 70 GHz, and somewhat shallower at 44 GHz. Planck?s source counts at 143 and 217 GHz join smoothly with the fainter ones provided by the SPT and ACT surveys over small fractions of the sky. An analysis of source spectra, exploiting Planck?s uniquely broad spectral coverage, finds clear evidence of a steepening of the mean spectral index above about 70 GHz. This implies that, at these frequencies, the contamination of the CMB power spectrum by radio sources below the detection limit is significantly lower than previously estimated.The Planck Collaboration thanks the referee, Ronald Ekers, for his insightful comments, which helped improve the paper. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MICINN and JA (Spain); Tekes, AoF and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); and DEISA (EU). A description of the Planck Collaboration and a list of its members can be found at http://www.rssd.esa.int/index.php?project=PLANCK&page=Planck_Collaboratio
Natural hazards in Australia: heatwaves
As part of a special issue on natural hazards, this paper reviews the current state of scientific knowledge of Australian heatwaves. Over recent years, progress has been made in understanding both the causes of and changes to heatwaves. Relationships between atmospheric heatwaves and large-scale and synoptic variability have been identified, with increasing trends in heatwave intensity, frequency and duration projected to continue throughout the 21st century. However, more research is required to further our understanding of the dynamical interactions of atmospheric heatwaves, particularly with the land surface. Research into marine heatwaves is still in its infancy, with little known about driving mechanisms, and observed and future changes. In order to address these knowledge gaps, recommendations include: focusing on a comprehensive assessment of atmospheric heatwave dynamics; understanding links with droughts; working towards a unified measurement framework; and investigating observed and future trends in marine heatwaves. Such work requires comprehensive and long-term collaboration activities. However, benefits will extend to the international community, thus addressing global grand challenges surrounding these extreme events
Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine
In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown
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