866 research outputs found
Soft X‐ray and ENA Imaging of the Earth’s Dayside Magnetosphere
No full textThe LEXI and SMILE missions will provide soft X‐ray images of the Earth's magnetosheath and cusps after their anticipated launch in 2023 and 2024, respectively. The IBEX mission showed the potential of an Energetic Neutral Atom (ENA) instrument to image dayside magnetosheath and cusps, albeit over the long hours required to raster an image with a single pixel imager. Thus, it is timely to discuss the two imaging techniques and relevant science topics. We simulate soft X‐ray and low‐ENA images that might be observed by a virtual spacecraft during two interesting solar wind scenarios: a southward turning of the interplanetary magnetic field and a sudden enhancement of the solar wind dynamic pressure. We employ the OpenGGCM global magnetohydrodynamics model and a simple exospheric neutral density model for these calculations. Both the magnetosheath and the cusps generate strong soft X‐rays and ENA signals that can be used to extract the locations and motions of the bow shock and magnetopause. Magnetopause erosion corresponds closely to the enhancement of dayside reconnection rate obtained from the OpenGGCM model, indicating that images can be used to understand global‐scale magnetopause reconnection. When dayside imagers are installed with high‐ENA inner‐magnetosphere and FUV/UV aurora imagers, we can trace the solar wind energy flow from the bow shock to the magnetosphere and then to the ionosphere in a self‐standing manner without relying upon other observatories. Soft X‐ray and/or ENA imagers can also unveil the dayside exosphere density structure and its response to space weather
Airway wall remodeling in asthma : novel mechanisms of human bronchial smooth muscle cells in the induction of angiogenesis
No full textAsthma is a global major health concern and it affects estimated 300 million people. The
prevalence of asthma is rising and there is no cure for asthma, only the symptoms can be
controlled. Acute asthma attacks are characterized by severe symptoms such as breathlessness,
wheezing, tightness of the chest, and coughing, which may lead to hospitalization or death.
Besides the acute symptoms, asthma is characterized by persistent airway inflammation and
airway wall remodeling. The term airway wall remodeling summarizes the structural changes in
the airway wall: epithelial cell shedding, goblet cell hyperplasia, hyperplasia and hypertrophy of
the bronchial smooth muscle (BSM) bundles, basement membrane thickening and increased
vascular density. Airway wall remodeling starts early in the pathogenesis of asthma and today it
is suggested that remodeling is a prerequisite for other asthma pathologies. Furthermore, novel
invasive therapies used to treat severe asthma provide evidence that the BSMC is a major
effector cell in the pathology of asthma.
In the present thesis novel mechanisms of BSMC regulation and their role in the induction of
asthma-associated angiogenesis have been elucidated. Therefore, the differences in the
angiogenic capacities of BSMC from asthma and non-asthma patients and their modification by
different conditions, such as an (i) inflammatory microenvironment, (ii) the influence of low
oxygen concentration, and (iii) the stimulation with the most potent asthma relevant allergen
(house dust mite (HDM) allergen) on the angiogenic properties of BSMC have been studied.
A major finding of this thesis is the increased angiogenic potential of BSMC from asthma
patients and the altered release of CXCR2 ligands in an in vitro inflammatory environment. It
has been demonstrated that BSMC from asthma patients release significantly more of the
CXCR2 ligands ENA-78, GRO-a and IL-8, which may explain the increased vascular density
in the sub-epithelial cell layers observed in the airways of asthma patients. These finding adds
to previous studies showing that BSMC are a source of angiogenic factors (e.g. VEGF) and that
CXCR2 ligands are elevated in the airway lining fluids of asthma patients. In this thesis BSMC
have been shown to be a potential source of CXCR2 ligands, which induced spout outgrowth
from endothelial cell spheroids in an in vitro model of angiogenesis.
Furthermore, this thesis investigated the effect of hypoxia on BSMC. Local restricted hypoxia
in the airways of asthma patients had only recently been suggested. The animal model based
hypothesis that hypoxia directly causes BSMC hyperplasia was tested. This hypothesis was not
confirmed in human BSMC but nonetheless it was demonstrated that hypoxia leads to
increased release of inflammatory and angiogenic mediators; as conditioned medium from
BSMC grown under hypoxia induced angiogenesis in an in vitro model via VEGF.
These findings suggest that different conditions or stimuli induce angiogenesis in asthma
through different pathways and therefore, different therapeutic strategies might be needed.
In the third part of this thesis the effect of HDM allergen on the release of inflammatory and
angiogenic mediators from BSMC was assessed. Animal models demonstrated that exposure to
HDM allergens increased airway wall vascularization. No direct contribution of BSMC to
HDM extract induced angiogenesis was observed. However, HDM extract proteases degraded
ENA-78, which is an import chemokine for neutrophil recruitment into the inflamed lung. Thus
HDM allergens may alter the bio-availability of ENA-78 in the airways of asthma patients and
modulate the immune response.
The findings of this thesis add a small piece to the knowledge of asthma pathology, the
mechanisms underlying airway wall remodeling and in particular BSMC hyperplasia and
neovascularization. This might represent novel targets for treatment, especially for the
prevention or reversal of airway wall remodeling
Hair casts due to a deodorant spray
No full textA 7-year-old girl presented with itching and greyish-white sleeve-like structures in her hair. After ruling out other possible causes for the symptoms, such as nits and dandruff, it was determined that the patient was affected by hair casts. These are small cylindrical structures resembling louse eggs that encircle individual scalp hairs and are easily movable along the hair shafts. It was concluded that she had induced the condition through misuse of a deodorant body spray. Scanning electron microscopy combined with electron dispersive X-ray analysis (X-ray microanalysis) of the hair casts showed the chemical nature of the structures. Some elements present in the composition of the ingredients of the deodorant spray, such as aluminium, chlorine, silicon, magnesium and carbon, were also present in this uncommon type of hair casts
“Alejarme del mundanal ruido”: autoría y régimen de visibilidad en Ena Lucía Portela
No full textConsidering the fact that the Cuban writer Ena Lucía Portela (1972) has not published an unpublished work for more than 10 years and has not participated in public activities, being confined at home, I present an approach to the construction of her image / position as an author based on the idea, and following Natalie Heinich, that in the case of Ena Lucía Portela there is an “enigmatization” of the author, that is built from an (in)visibility regime of media, in which the enigmas of her health and of her next novel function as one of the main engines of discursive production around her authorial image, in the construction of her portrait as an author. For this I use different texts that are inscribed in these forms of life writings, in those experiential and self-referential narratives, particularly: the essays and its explanatory notes of her book Con hambre y sin dinero (2017) and some interviews and biographical sketch.Atendiendo al hecho de que la escritora cubana Ena Lucía Portela (1972) lleva más de 10 años sin publicar una obra inédita y sin participar en actividades públicas, estando recluida en su casa, presento una aproximación a la construcción de su imagen/postura de autora a partir de la idea, y siguiendo a Natalie Heinich, de que en el caso de Ena Lucía Portela hay una “enigmatización” de la autora, construida desde un régimen de (in)visibilidad mediática, en el que los enigmas de su salud y de su próxima novela funcionan como uno de los principales motores de la producción discursiva en torno a su imagen autorial, en la construcción de su retrato de autora. Para ello me sirvo de diferentes textos que se inscriben en esas formas de escrituras de vida, en esas narrativas vivenciales y autorreferenciales, particularmente: los ensayos y notas aclaratorias de su libro Con hambre y sin dinero (2017) y algunas entrevistas y semblanzas
Ena/VASP proteins have an anti-capping independent function in filopodia formation
No full textAuthor Posting. © American Society for Cell Biology, 2007. This article is posted here by permission of American Society for Cell Biology for personal use, not for redistribution. The definitive version was published in Molecular Biology of the Cell 18 (2007): 2579-2591, doi:10.1091/mbc.E06-11-0990.Filopodia have been implicated in a number of diverse cellular processes including growth-cone path finding, wound healing, and metastasis. The Ena/VASP family of proteins has emerged as key to filopodia formation but the exact mechanism for how they function has yet to be fully elucidated. Using cell spreading as a model system in combination with small interfering RNA depletion of Capping Protein, we determined that Ena/VASP proteins have a role beyond anticapping activity in filopodia formation. Analysis of mutant Ena/VASP proteins demonstrated that the entire EVH2 domain was the minimal domain required for filopodia formation. Fluorescent recovery after photobleaching data indicate that Ena/VASP proteins rapidly exchange at the leading edge of lamellipodia, whereas virtually no exchange occurred at filopodial tips. Mutation of the G-actin–binding motif (GAB) partially compromised stabilization of Ena/VASP at filopodia tips. These observations led us to propose a model where the EVH2 domain of Ena/VASP induces and maintains clustering of the barbed ends of actin filaments, which putatively corresponds to a transition from lamellipodial to filopodial localization. Furthermore, the EVH1 domain, together with the GAB motif in the EVH2 domain, helps to maintain Ena/VASP at the growing barbed ends.This work was supported in
part by National Institutes of Health Grants GM7542201 to D.A.A., GM58801
to F.B.G., and GM62431 to G.G.B. and by Cell Migration Consortium Grants
GM64346 to D.A.A and G.G.B
Revisiting the distribution of Thaumetopoea pityocampa (Lepidoptera: Notodontidae) and T. pityocampa ENA Clade in Greece
No full textIn the present work, we sampled individuals of the processionary pine moth, Thaumetopoea pityocampa (Denis and Schiffermüller; Lepidoptera: Notodontidae) from different areas of Greece between 2014 and 2016. These samples were sequenced for a 760-bp long mtDNA COI locus and the haplotypes retrieved clearly showed that the occurrence of T. pityocampa in Greece is being considerably restricted, with only 8 individuals out of the 221 exhibiting T. pityocampa haplotypes and the rest being identified as T. pityocampa ENA clade haplotypes. To that, one haplotype in particular exhibited the highest abundance and broadest geographic distribution, occurring both in mainland and on islands. Our data suggest a rather recent and rapid population expansion of the ENA clade in Greece and a concomitant recent displacement of T. pityocampa. It thus seems that the relation between T. pityocampa and T. pityocampa ENA clade needs to be further and thorough analyzed before the taxonomic status of T. pityocampa ENA clade can be concluded with confidence. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved
New data on the range expansion of the Thaumetopoea pityocampa (Lepidoptera: Notodontidae) ‘ENA clade’ in Greece:The role of bacterial endosymbionts
No full textThe pine processionary moth, Thaumetopoea pityocampa (Denis and Schiffermüller), is an important insect in the Mediterranean region, as it defoliates pines and its urticating hairs can cause allergic reactions in humans and animals. Moreover, this species exhibits an interesting genetic structure as recently a distinct East-North African mtDNA lineage (‘ENA clade’) has been described.This clade has been recently detected in Greek populations where it has currently expanded its range by replacing the ‘endemic’ T. pityocampa lineages. Here, we report new data on the rapid spread of ‘ENA clade’ in the Greek island Evoia in only a few years. As the underlying mechanisms of the ‘ENA clade’ range expansion has not been studied so far, we screened T. pityocampa for an infection with the heritable bacterial endosymbionts Wolbachia (Bacteria: Anaplasmataceae), Cardinium (Bacteria: Bacteroidaceae), Rickettsia (Bacteria: Rickettsiaceae) and Spiroplasma (Bacteria: Spiroplasmataceae). These bacteria can manipulate the reproduction of infected hosts, something that could potentially explain the rapid spread of ‘ENA clade’ lineage. Therefore, we screened 28 individuals that exhibited T. pityocampa ‘ENA clade’ and ‘endemic’ T. pityocampa haplotypes from nine populations scattered all over Greece. None of them was infected with any of the four endosymbionts, suggesting that these bacteria do not cause reproductive manipulations in T. pityocampa lineages and, thus, other factors should be explored in future research efforts. © The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved
Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato
No full textWild-type (WT) plants of potato (Solanum tuberosum L.) and their transgenic forms carrying agrobacterial genes rolB or rolC under the control of B33 class I patatin promoter were cultured in vitro on MS medium with 2% sucrose in a controlled-climate chamber at 16-h illumination and 22A degrees C. These plants were used as a source of single-node stem cuttings, which were cultured in darkness on the same medium supplemented with 8% sucrose. The tubers formed on them were used for determination of the structure of native starch using the methods of differential scanning microcalorimetry (DSC), X-ray scattering, and scanning electron microscopy. It was found that, in starch from the tubers of rolB-plants, the temperature of crystalline lamella melting was lower and their thickness was less than in WT potato. In tubers of rolC plants, starch differed from starch in WT plants by a higher melting temperature, considerably reduced melting enthalpy, and a greater thickness of crystalline lamellae. Deconvolution of DSC thermogram makes it possible to interpret the melting of starch from the tubers of rolC plants as the melting of two independent crystalline structures with melting temperatures of 65.0 and 69.8A degrees C. Electron microscopic examination confirmed the earlier obtained data indicating that, in the tubers of rolC plants, starch granules are smaller and in the tubers of rolB plants larger than in WT plants. Possible ways of influence of rol transgenes on structural properties of starch in amyloplasts of potato tubers are discusse
“Tan oscuro como muy oscuro”: ¿dónde se ubica Ena Lucía Portela? = "As dark as very dark”: Where does Ena Lucía Portela stand?
No full textThe aim of the article is to study “As dark as
very dark”, a short, less known text by Cuban author
Ena Lucía Portela (1972). After commenting on its
place in the context of the volume edited by Iván de
la Nuez: Cuba y el día después: doce ensayistas nacidos
con la revolución imaginan el futuro (2002), we argue
that the question concerning Cuba’s future serves as
a pretext for Portela to try to defi ne her place as a Cuban
writer and as intellectual. She distances from the
literary currents that determined the Cuban literary
fi eld, and destabilizes her own position. The protagonist’s
characterization as a nowhere girl, the intertextuality
and the emphasis on scepticism illustrate her
elusive position that doesn’t fi t in any category.Nos proponemos estudiar “Tan oscuro
como muy oscuro”, un texto breve, menos conocido,
de la escritora cubana Ena Lucía Portela (1972).
Tras ubicar el texto en el volumen editado por Iván
de la Nuez, Cuba y el día después: doce ensayistas
nacidos con la revolución imaginan el futuro (2002),
argüimos que la pregunta sobre el futuro de Cuba le
sirve a Portela como pretexto para intentar defi nir su
lugar como intelectual y escritora cubana. No sólo
se distancia de las corrientes que han imperado en
el campo literario cubano, sino que desestabiliza su
propia ubicación. La caracterización de la protagonista
como nowhere girl, la intertextualidad y la insistencia
en el escepticismo ilustran su posición siempre
escurridiza que no cabe en ninguna categoría
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