4,015 research outputs found

    Polarization-Tailored Raman Frequency Conversion in Chiral Gas-Filled Hollow Core Photonic Crystal Fibers

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    Broadband-tunable sources of circularly-polarized light are crucial in fields such as laser science, biomedicine and spectroscopy. Conventional sources rely on nonlinear wavelength conversion and polarization control using standard optical components, and are limited by the availability of suitably transparent crystals and glasses. Although gas-filled hollow-core photonic crystal fiber provides pressure-tunable dispersion, long well-controlled optical path-lengths, and high Raman conversion efficiency, it is unable to preserve circular polarization state, typically exhibiting weak linear birefringence. Here we report a revolutionary approach based on helically-twisted hollow-core photonic crystal fiber, which displays circular birefringence, thus robustly maintaining circular polarization state against external perturbations. This makes it possible to generate pure circularly-polarized Stokes and anti-Stokes signals by rotational Raman scattering in hydrogen. The polarization state of the frequency-shifted Raman bands can be continuously varied by tuning the gas pressure in the vicinity of the gain suppression point. The results pave the way to a new generation of compact and efficient fiber-based sources of broadband light with fully-controllable polarization state.Comment: 5 pages, 4 figure

    Nanoplastics: From tissue accumulation to cell translocation into Mytilus galloprovincialis hemocytes. resilience of immune cells exposed to nanoplastics and nanoplastics plus Vibrio splendidus combination

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    Plastic litter is an issue of global concern. In this work Mytilus galloprovincialis was used to study the distribution and effects of polystyrene nanoplastics (PS NPs) of different sizes (50 nm, 100 nm and 1 mu m) on immune cells. Internalization and translocation of NPs to hemolymph were carried out by in vivo experiments, while endocytic routes and effects of PS NPs on hemocytes were studied in vitro. The smallest PS NPs tested were detected in the digestive gland and muscle. A fast and size-dependent translocation of PS NPs to the hemolymph was recorded after 3 h of exposure. The internalization rate of 50 nm PS NPs was lower when caveolae and clathrin endocytosis pathways were inhibited. On the other hand, the internalization of larger particles decreased when phagocytosis was inhibited. The hemocytes exposed to NPs had changes in motility, apoptosis, ROS and phagocytic capacity. However, they showed resilience when were infected with bacteria after PS NP exposure being able to recover their phagocytic capacity although the expression of the antimicrobial peptide Myticin C was reduced. Our findings show for the first time the translocation of PS NPs into hemocytes and how their effects trigger the loss of its functional parameters

    Novel mid-infrared dispersive wave generation in gas-filled PCF by transient ionization-driven changes in dispersion

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    Gas-filled hollow-core photonic crystal fibre (PCF) is being used to generate ever wider supercontinuum spectra, in particular via dispersive wave (DW) emission in the deep and vacuum ultraviolet, with a multitude of applications. DWs are the result of the resonant transfer of energy from a self-compressed soliton, a process which relies crucially on phase matching. It was recently predicted that, in the strong-field regime, the additional transient anomalous dispersion introduced by gas ionization would allow phase-matched DW generation in the mid-infrared (MIR)-something that is forbidden in the absence of free electrons. Here we report for the first time the experimental observation of such MIR DWs, embedded in a 4.7-octave-wide supercontinuum that uniquely reaches simultaneously to the vacuum ultraviolet, with up to 1.7 W of total average power

    Overexpression of the short endoglin isoform reduces renal fibrosis and inflammation after unilateral ureteral obstruction

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    33 p.-9 fig.-2 tab. Muñoz-Felix. J. M. et al.Transforming growth factor beta 1 (TGF-β1) is one of the most studied cytokines involved in renal tubulo¬interstitial fibrosis, which is characterized by myofibroblast abundance and proliferation, and high buildup of extracellular matrix in the tubular interstitium leading to organ failure. Endoglin (Eng) is a 180-kDa homodimeric transmembrane protein that regulates a great number of TGF-β1 actions in different biological processes, includ¬ing ECM synthesis. High levels of Eng have been observed in experimental models of renal fibrosis or in biopsies from patients with chronic kidney disease. In humans and mice, two Eng isoforms are generated by alternative splicing, L-Eng and S-Eng that differ in the length and composition of their cytoplasmic domains. We have previously described that L-Eng overexpression promotes renal fibrosis after unilateral ureteral obstruction (UUO). However, the role of S-Eng in renal fibrosis is unknown and its study would let us analyze the possible function of the cytoplasmic domain of Eng in this process. For this purpose, we have generated a mice strain that overexpresses S-Eng (S-ENG+) and we have performed an UUO in S-ENG+ and their wild type (WT) control mice. Our results indicate that obstructed kidney of S-ENG+ mice shows lower levels of tubulo-interstitial fibrosis, less inflammation and less interstitial cell proliferation than WT littermates. Moreover, S-ENG+ mice show less activation of Smad1 and Smad2/3 pathways. Thus, S-Eng overexpression reduces UUO-induced renal fibrosis and some associated mechanisms. As L-Eng overexpression provokes renal fibrosis we conclude that Eng-mediated induction of renal fibrosis in this model is dependent on its cytoplasmic domain.This study has been supported by grants from Ministerio de Economía y Competitividad of Spain (SAF2013-43421-R to CB; and SAF2013-45784-R to JML-N), Junta de Castilla y León (GR100, JML-N), Institute Queen Sophie for Renal Research, Fundación Renal Íñigo Álvarez de Toledo, Madrid, Spain (0016¬002), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER, CB) (ISCIII-CB06/07/0038) and Red de Investigación Cooperativa en Enfermedades Renales (REDINREN, JML-N) (R12/0021/ 0032). CIBERER and REDINREN are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain supported by FEDER funds. BO and ENG are supported by fellowships from Ministerio de Economía y Competitividad (BES-2011-048968 and BES-2008-005550). JMMF, LPR and CC are supported by fellowships from Junta de Castilla y León and Fondo Social Europeo (EDU/1204/2010 and EDU/1083/2013).Peer reviewe

    Endoglin involvement in integrin-mediated cell adhesion as a putative pathogenic mechanism in hereditary hemorrhagic telangiectasia type 1 (HHT1)

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    5 p.-2 fig.Mutations in the endoglin gene (ENG) are responsible for ∼50% of all cases with hereditary hemorrhagic telangiectasia (HHT). Because of the absence of effective treatments for HHT symptoms, studies aimed at identifying novel biological functions of endoglin which could serve as therapeutic targets of the disease are needed. Endoglin is an endothelial membrane protein, whose most studied function has been its role as an auxiliary receptor in the TGF-β receptor complex. However, several lines of evidence suggest the involvement of endoglin in TGF-β-independent functions. Endoglin displays, within its zona pellucida domain, an RGD motif, which is a prototypic sequence involved in integrin-based interactions with other proteins. Indeed, we have recently described a novel role for endothelial endoglin in leukocyte trafficking and extravasation via its interaction with leukocyte integrins. In addition, functional, as well as protein and gene expression analysis have shown that ectopic endoglin represses the synthesis of several members of the integrin family and modulates integrin-mediated cell adhesions. This review focuses on the tight link between endoglin and integrins and how the role of endothelial endoglin in integrin-dependent cell adhesion processes can provide a better understanding of the pathogenic mechanisms leading to vascular lesions in endoglin haploinsufficient HHT1 patients.This study was supported by grants from the Ministerio de Economia y Competitividad of Spain (SAF2010-19222 and SAF2013-43421-R to Carmelo Bernabeu; SAF2010-1588, SAF2013-45784-R, and RD12/0021/0032-REDINREN to José M. Lopez-Novoa).Peer reviewe

    LEDGF/p75 TATA-less promoter is driven by the transcription factor Sp1.

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    PSIP1 (PC4 and SFRS1 interacting protein 1) encodes two splice variants: lens epithelium-derived growth factor or p75 (LEDGF/p75) and p52. PSIP1 gene products were shown to be involved in transcriptional regulation, affecting a plethora of cellular processes, including cell proliferation, cell survival, and stress response. Furthermore, LEDGF/p75 has implications for various diseases and infections, including autoimmunity, leukemia, embryo development, psoriasis, and human immunodeficiency virus integration. Here, we reported the first characterization of the PSIP1 promoter. Using 5' RNA ligase-mediated rapid amplification of cDNA ends, we identified novel transcription start sites in different cell types. Using a luciferase reporter system, we identified regulatory elements controlling the expression of LEDGF/p75 and p52. These include (i) minimal promoters (-112/+59 and +609/+781) that drive the basal expression of LEDGF/p75 and of the shorter splice variant p52, respectively; (ii) a sequence (+319/+397) that may control the ratio of LEDGF/p75 expression to p52 expression; and (iii) a strong enhancer (-320/-207) implicated in the modulation of LEDGF/p75 transcriptional activity. Computational, biochemical, and genetic approaches enabled us to identify the transcription factor Sp1 as a key modulator of the PSIP1 promoter, controlling LEDGF/p75 transcription through two binding sites at -72/-64 and -46/-36. Overall, our results provide initial data concerning LEDGF/p75 promoter regulation, giving new insights to further understand its biological function and opening the door for new therapeutic strategies in which LEDGF/p75 is involved

    Endoglin Regulates Cyclooxygenase-2 Expression and Activity

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    Jerkic, Mirjana[et alt.] 9 p.-8 fig.The endoglin heterozygous (Eng+/−) mouse, which serves as a model of hereditary hemorrhagic telangiectasia (HHT), was shown to express reduced levels of endothelial NO synthase (eNOS) with impaired activity. Because of intricate changes in vasomotor function in the Eng+/− mice and the potential interactions between the NO- and prostaglandin-producing pathways, we assessed the expression and function of cyclooxygenase (COX) isoforms. A specific upregulation of COX-2 in the vascular endothelium and increased urinary excretion of prostaglandin E2 were observed in the Eng+/− mice. Specific COX-2 inhibition with parecoxib transiently increased arterial pressure in Eng+/− but not in Eng+/+ mice. Transfection of endoglin in L6E9 myoblasts, shown previously to stimulate eNOS expression, led to downregulation of COX-2 with no change in COX-1. In addition, COX-2 promoter activity and protein levels were inversely correlated with endoglin levels, in doxycyclin-inducible endothelial cells. Chronic NO synthesis inhibition with Nω-nitro-l-arginine methyl ester induced a marked increase in COX-2 only in the normal Eng+/+ mice. Nω-nitro-l-arginine methyl ester also increased COX-2 expression and promoter activity in doxycyclin-inducible endoglin expressing endothelial cells, but not in control cells. The level of COX-2 expression following transforming growth factor-β1 treatment was less in endoglin than in mock transfected L6E9 myoblasts and was higher in human endothelial cells silenced for endoglin expression. Our results indicate that endoglin is involved in the regulation of COX-2 activity. Furthermore, reduced endoglin levels and associated impaired NO production may be responsible, at least in part, for augmented COX-2 expression and activity in the Eng+/− miceThis work was supported by grants from Ministerio de Educacion y Ciencia (SAF2001/1701 to J.M.L.-N. and SAF2004–01390 to C.B.), Fondo de Investigación Sanitaria (PI020200 to C.B.), HHT Foundation International to C.B., and by the Heart and Stroke Foundation of Canada (T5016) to M.L. M.J. was supported by a Fellowship from Instituto Reina Sofía de Investigación Nefrológica. C.P.H.V. was supported by NIH grant #P2015555 from the National Center for Research ResourcesPeer reviewe

    Proposal to inform European institutions regarding the regulation of conscientious objection to abortion.

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    The aim of this paper is to define a set of proposals to inform European institutions in the regulation of Conscientious Objection to abortion. The board of the European Society of Contraception and Reproductive Health Care (ESC) was informed on the elements that should in the opinion of the authors be included in a future regulation of Conscientious Objection to abortion in Europe. These elements are outlined in this paper and the debate about them could form the basis for recommendations to the international scientific community and the European institutions. As current measures governing the principle of conscientious objection result in negative consequences regarding women's access to sexual and reproductive health services, they should be changed. Healthcare services should adopt measures to guarantee that a woman's right to voluntary abortion is not limited by the practitioner's stance on the principle of conscientious objection. In the countries where conscientious objection is allowed, the regulation must clearly delineate the extent of the duties and the exemptions of professionals based on the principles of established social consensus. The recommendations included in this document specify measures on the rights of women, the rights and duties of the practitioner, the role of institutions and the role of professional associations
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