αV-Integrins Are Required for Mechanotransduction in MDCK Epithelial Cells

The properties of epithelial cells within tissues are regulated by their immediate microenvironment, which consists of neighboring cells and the extracellular matrix (ECM). Integrin heterodimers orchestrate dynamic assembly and disassembly of cell-ECM connections and thereby convey biochemical and mechanical information from the ECM into cells. However, the specific contributions and functional hierarchy between different integrin heterodimers in the regulation of focal adhesion dynamics in epithelial cells are incompletely understood. Here, we have studied the functions of RGD-binding αV-integrins in a Madin Darby Canine Kidney (MDCK) cell model and found that αV-integrins regulate the maturation of focal adhesions (FAs) and cell spreading. αV-integrin-deficient MDCK cells bound collagen I (Col I) substrate via α2β1-integrins but failed to efficiently recruit FA components such as talin, focal adhesion kinase (FAK), vinculin and integrin-linked kinase (ILK). The apparent inability to mature α2β1-integrin-mediated FAs and link them to cellular actin cytoskeleton led to disrupted mechanotransduction in αV-integrin deficient cells seeded onto Col I substrate

A multi-technique approach to study the microstructural properties of tin-based transparent conductive oxides

Transparent conductive oxides (TCOs) are semiconductor-like materials that exhibit high electrical conductivity and high optical transparency combined. They are adopted in various applications ranging from gas sensors, to electrochromic windows, to photovoltaic cells. Indium-based TCOs represent the industry standard. Nevertheless, indium is among the less abundant elements in the earth crust and forecasts based on its current consumption envisage an urgent need to replace it. Tin-based TCOs are a promising alternative, since their opto- electronic characteristics mimic the ones of indium-based materials. This thesis aims to investigate the link between optoelectronic and microstructural properties of tin dioxide and zinc tin oxide (ZTO) with a composition Zn0.05Sn0.30O0.65 and their stability when submitted to thermal treatments. Indeed, lots of practi- cal applications require the TCO to operate in high temperature conditions. To conduct this study, a combination of analytical techniques, such as transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X- ray diffraction (XRD), electron paramagnetic resonance (EPR) and differential scanning calorimetry (DSC) was employed. Amorphous SnO2 and ZTO were deposited by RF sputtering and annealed up to 1050°C in different atmospheres. The influence of annealing temperature and atmosphere were decoupled and led us to an in-depth comprehension of the mechanisms governing the optoelectronic properties of both materials. When annealed in air, between room temperature and 300°C, ZTO exhibits increased mobility and carrier concentration with respect to the as-deposited state. This increase, investigated with DSC, was ascribed to a structural relaxation that allows point defects to release electrons in conduction band. Between 300°C and 500°C atmospheric oxygen passivates oxygen vacancies, drastically decreasing the carrier concentration and therefore causing a large drop of the conductivity. EPR experiments allowed to ascribe the drop in conductivity to the decrease of carrier concentration, which occurs slightly before the phase change. At 570°C (and 930°C for the case of vacuum annealing) the phase change occurs and the ZTO crystallizes in the rutile form of SnO2. The material becomes completely insulating. When the temperature is increased to 1050°C, evaporation of zinc is observed. In order to improve the electrical conductivity of ZTO at high temperature, a doping strategy was implemented starting from DFT calculations conducted by a partner group, who screened among the entire periodic table, which elements are the best candidates to act as n-dopants for ZTO. Bromine and iodine were retained, since they were found to be the most energetically favorable to become substitutional defects for a tin site. An exploratory doping route is therefore presented and the treated samples analyzed with TEM, EDX and UV-VIS-IR spectroscopy. Finally, the structural properties of an indium-based TCO (zirconium-doped indium oxide) were investigated and used as a benchmark to propose a crystallization model for the tin-based, as well as the indium-based materials. The influence of pa- rameters such as the material thickness, annealing atmosphere and temperature and deposition pressure are discussed for both materials

COVID-19 stressors and health behaviors. A multilevel longitudinal study across 86 countries

Anxiety associated with the COVID-19 pandemic and home confinement has been associated with adverse health behaviors, such as unhealthy eating, smoking, and drinking. However, most studies have been limited by regional sampling, which precludes the examination of behavioral consequences associated with the pandemic at a global level. Further, few studies operationalized pandemic-related stressors to enable the investigation of the impact of different types of stressors on health outcomes. This study examined the association between perceived risk of COVID-19 infection and economic burden of COVID-19 with health-promoting and health-damaging behaviors using data from the PsyCorona Study: an international, longitudinal online study of psychological and behavioral correlates of COVID-19. Analyses utilized data from 7,402 participants from 86 countries across three waves of assessment between May 16 and June 13, 2020. Participants completed self-report measures of COVID-19 infection risk, COVID-19-related economic burden, physical exercise, diet quality, cigarette smoking, sleep quality, and binge drinking. Multilevel structural equation modeling analyses showed that across three time points, perceived economic burden was associated with reduced diet quality and sleep quality, as well as increased smoking. Diet quality and sleep quality were lowest among respondents who perceived high COVID-19 infection risk combined with high economic burden. Neither binge drinking nor exercise were associated with perceived COVID-19 infection risk, economic burden, or their interaction. Findings point to the value of developing interventions to address COVID-related stressors, which have an impact on health behaviors that, in turn, may 111 influence vulnerability to COVID-19 and other health outcomes

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Anchors for the cosmic distance scale : the Cepheids U Sagittarii, CF Cassiopeiae, and CEab Cassiopeiae

New and existing X-ray, UBVJHKsW(1−4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance because they host the classical Cepheids USgr, CF Cas, and the visual binary Cepheids CEa and CEb Cas. Precise results from the multiband analysis, in tandem with a comprehensive determination of the Cepheids’ period evolution (dP/dt) from ∼140 years of observations, helped to resolve concerns raised regarding the clusters and their key Cepheid constituents. Specifically, the distances derived for members of M25 and NGC7790 are 630 ± 25 pc and 3.40 ± 0.15 kpc, respectively

αV-Integrins Are Required for Mechanotransduction in MDCK Epithelial Cells

The properties of epithelial cells within tissues are regulated by their immediate microenvironment, which consists of neighboring cells and the extracellular matrix (ECM). Integrin heterodimers orchestrate dynamic assembly and disassembly of cell-ECM connections and thereby convey biochemical and mechanical information from the ECM into cells. However, the specific contributions and functional hierarchy between different integrin heterodimers in the regulation of focal adhesion dynamics in epithelial cells are incompletely understood. Here, we have studied the functions of RGD-binding αV-integrins in a Madin Darby Canine Kidney (MDCK) cell model and found that αV-integrins regulate the maturation of focal adhesions (FAs) and cell spreading. αV-integrin-deficient MDCK cells bound collagen I (Col I) substrate via α2β1-integrins but failed to efficiently recruit FA components such as talin, focal adhesion kinase (FAK), vinculin and integrin-linked kinase (ILK). The apparent inability to mature α2β1-integrin-mediated FAs and link them to cellular actin cytoskeleton led to disrupted mechanotransduction in αV-integrin deficient cells seeded onto Col I substrate.</p

BAMBI is a novel HIF1-dependent modulator of TGFβ-mediated disruption of cell polarity during hypoxia

Abstract Hypoxia and loss of cell polarity are common features of malignant carcinomas. Hypoxia-inducible factor 1 (HIF1) is the major regulator of cellular hypoxia response and mediates the activation of ∼300 genes. Increased HIF1 signaling is known to be associated with epithelial–mesenchymal transformation. Here, we report that hypoxia disrupts polarized epithelial morphogenesis of MDCK cells in a HIF1α-dependent manner by modulating the transforming growth factor-β (TGFβ) signaling pathway. Analysis of potential HIF1 targets in the TGFβ pathway identified the bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI), a transmembrane glycoprotein related to the type I receptors of the TGFβ family, whose expression was essentially lost in HIF1-depleted cells. Similar to what was observed in HIF1-deficient cells, BAMBI-depleted cells failed to efficiently activate TGFβ signaling and retained epithelial polarity during hypoxia. Taken together, we show that hypoxic conditions promote TGFβ signaling in a HIF1-dependent manner and BAMBI is identified in this pathway as a novel HIF1-regulated gene that contributes to hypoxia-induced loss of epithelial polarity

Anchors for the cosmic distance scale : the Cepheids U Sagittarii, CF Cassiopeiae, and CEab Cassiopeiae

New and existing X-ray, UBVJHKsW(1−4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance because they host the classical Cepheids USgr, CF Cas, and the visual binary Cepheids CEa and CEb Cas. Precise results from the multiband analysis, in tandem with a comprehensive determination of the Cepheids’ period evolution (dP/dt) from ∼140 years of observations, helped to resolve concerns raised regarding the clusters and their key Cepheid constituents. Specifically, the distances derived for members of M25 and NGC7790 are 630 ± 25 pc and 3.40 ± 0.15 kpc, respectively

The burden of skin disease in the United States

Since the publication of the last US national burden of skin disease report in 2006, there have been substantial changes in the practice of dermatology and the US health care system. These include the development of new treatment modalities, marked increases in the cost of medications, increasingly complex payer rules and regulations, and an aging of the US population. Recognizing the need for up-to-date data to inform researchers, policy makers, public stakeholders, and health care providers about the impact of skin disease on patients and US society, the American Academy of Dermatology produced a new national burden of skin disease report. Using 2013 claims data from private and governmental insurance providers, this report analyzed the prevalence, cost, and mortality attributable to 24 skin disease categories in the US population. In this first of 3 articles, the presented data demonstrate that nearly 85 million Americans were seen by a physician for at least 1 skin disease in 2013. This led to an estimated direct health care cost of $75 billion and an indirect lost opportunity cost of$11 billion. Further, mortality was noted in half of the 24 skin disease categories

αV-integrins do not contribute to early adhesion to collagen I in MDCK cells.

<p><b>A</b>) Quantifying early cell adhesion by SCFS. Single control or ItgαV-KD cells were captured onto ConA-coated AFM cantilevers and pressed onto Col I-coated substrates. After the indicated contact times, cells were lifted from the substrate, and the maximum detachment force was recorded as described in materials and methods. More than 100 F–D curves were recorded for each condition. Mean+SD is shown. <b>B</b>) The maximum detachment force between collagen I substrate and control or Itgα2-KD MDCK cells was measured in the absence and presence of antibodies that block β1-integrin adhesion (AIIB2). At least 20 cells were analyzed for each condition. Values show mean ± SD. Membrane tether analysis (see T in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0071485#pone.0071485.s003" target="_blank">Fig. S3A</a></b>): <b>C</b>) The distributions of tether rupture forces for control and ItgαV-KD cells both center at a value of ≈92 pN, indicating no differences in cell membrane properties. 78 F–D curves for control and 41 F–D curves for ItgαV-KD cells were analyzed. <b>D</b>) Membrane tether length analysis of control and ItgαV-KD cells to identify possible differences of receptor affinity and cell membrane-cortex interactions. A very similar tether length distribution does not indicate any changes. To assure that analyzed rupture events exclusively originated from membrane tethers force steps within 7 µm after the maximum detachment force were omitted from analysis. <b>E</b>) Control and two independent ItgαV-KD MDCK cell lines were allowed to spread on Col I-coated plastic tissue culture dishes for 75 minutes followed by surface biotinylation. After cell lysis, biotin-bound molecules were precipitated with avidin-beads and relative amounts of β1-and α2-integrins in biotinylated vs. total lysates were determined by SDS-PAGE and western blotting as described in materials and methods. E-Cadherin (E-Cad, asterisk indicates an intracellular precursor of E-Cad) and β-actin were used as biotinylation and loading controls. ns  =  non-specific. <b>F</b>) Quantification of the relative surface expression of β1- and α2-integrins in the indicated cell lines.</p