929 research outputs found

    Test for contamination of MgF2 - coated mirrors

    Get PDF
    Graphs show preflight and postflight reflectivities in percent for exposed and covered mirrors carried on the OSS-1 payload pallet during STS-3. No changes greater than 1.8 sigma were observed except for a fingerprint. Weak evidence for degradation at 1216 A and 1600 A was found in several samples. There was no difference between flight mirrors and control mirrors. Covered samples suffered more than samples exposed to the Sun, but the differences are barely significant. The exposed side of the flight mirrors were somewhat dusty. No evidence was found for permanent solar-induced or shuttle-induced deterioration. There also was no evidence on oil-pumped vacuum versus oil-free vacuum during coating

    Applied neutron tomography in modern archaeology

    Get PDF
    The use of neutron tomography for archaeometric purposes is quite a new technique. The property of neutron to transmit easily large, dense samples is of great importance in modern archaeology. The three-dimensional visualisation of the inner structure of samples of archaeological interest helps to make suggestions about the technological process of manufacturing or reveals information about the origins of delivering of noble materials used in ancient masterpieces. Another application field in modern archaeology is the non-destructive inspection of the quality of specimen conservation where the neutron tomography allows visualization of impregnation solutions in wood or metal matrices. The high sensibility of neutrons to hydrogen makes it possible to detect organic remains in fossils. All of these advantages make the neutron tomography a unique technique for non-destructive investigation in archaeological sciences

    Blocking CD248 molecules in perivascular stromal cells of patients with systemic sclerosis strongly inhibits their differentiation toward myofibroblasts and proliferation: A new potential target for antifibrotic therapy

    Get PDF
    Background: Fibrosis may be considered the hallmark of systemic sclerosis (SSc), the end stage triggered by different pathological events. Transforming growth factor-β (TGF-β) and platelet-derived growth factor BB (PDGF-BB) are profibrotic molecules modulating myofibroblast differentiation and proliferation, respectively. There is evidence linking CD248 with these two molecules, both highly expressed in patients with SSc, and suggesting that CD248 may be a therapeutic target for several diseases. The aim of this work was to evaluate the expression of CD248 in SSc skin and its ability to modulate SSc fibrotic process. Methods: After ethical approval was obtained, skin biopsies were collected from 20 patients with SSc and 10 healthy control subjects (HC). CD248 expression was investigated in the skin, as well as in bone marrow mesenchymal stem cells (MSCs) treated with TGF-β or PDGF-BB, by immunofluorescence, qRT-PCR, and Western blotting. Finally, in SSc-MSCs, the CD248 gene was silenced by siRNA. Results: Increased expression of CD248 was found in endothelial cells and perivascular stromal cells of SSc skin. In SSc-MSCs, the levels of CD248 and α-smooth muscle actin expression were significantly higher than in HC-MSCs. In both SSc- and HC-MSCs, PDGF-BB induced increased expression of Ki-67 when compared with untreated cells but was unable to modulate CD248 levels. After CD248 silencing, both TGF-β and PDGF-BB signaling were inhibited in SSc-MSCs. Conclusions: CD248 overexpression may play an important role in the fibrotic process by modulating the molecular target, leading to perivascular cells differentiation toward myofibroblasts and interfering with its expression, and thus might open a new therapeutic strategy to inhibit myofibroblast generation during SSc

    Successful intravenous immunoglobulin treatment for steroid-resistant eosinophilic enteritis in a patient with systemic lupus erythematosus.

    Get PDF
    Eosinophilic gastroenteritis is a rare condition of unknown etiology characterized by eosinophilic infiltration of the bowel. Corticosteroids are the mainstay of EG therapy. Although rare, steroid-resistant EG could be a life-threatening condition with tissue destructive evolution. Associations of eosinophilic gastroenteritis with systemic lupus erythematosus have rarely been reported. In this report we describe a case of successful IVIG treatment in a patient with systemic lupus erythematosus and steroid-refractory eosinophilic gastroenteritis

    Neutron tomography in modern archaeology

    Get PDF
    The search for non invasive and non destructive techniques is fundamental when dealing with samples of great historical, cultural and artistic value as well as with samples strongly degraded. Among different techniques, Neutron Tomography NT allows a close analysis of samples of Archaeological interest without damaging them. In what follows, a few cases in which the Neutron Tomography instrument of the BENSC at HMI Berlin has been successfully applied will be show

    Gonadotrophin-releasing hormone analogue or dienogest plus estradiol valerate to prevent pain recurrence after laparoscopic surgery for endometriosis: a multi-center randomized trial.

    Get PDF
    Abstract Objectives To evaluate the efficacy of dienogest + estradiol valerate (E2V) and gonadotrophin-releasing hormone analogue (GnRH-a) in reducing recurrence of pain in patients with chronic pelvic pain due to laparoscopically diagnosed and treated endometriosis. Design Multi-center, prospective, randomized study. Setting Three university departments of obstetrics and gynecology in Italy. Population Seventy-eight women who underwent laparoscopic surgery for endometriosis combined with chronic pelvic pain. Methods Post-operative administration of dienogest + E2V for 9 months (group 1) or GnRH-a monthly for 6 months (group 2). Main outcome measures A visual analogue scale was used to test intensity of pain before laparoscopic surgery at 3, 6 and 9 months of follow up. A questionnaire to investigate quality of life was administered before surgery and at 9 months of follow up. Results The visual analogue scale score did not show any significant differences between the two groups (p = 0.417). The questionnaire showed an increase of scores for all women compared with pre-surgery values, demonstrating a marked improvement in quality of life and health-related satisfaction with both treatments. No significant differences were found between the groups. The rate of apparent endometriosis recurrence was 10.8% in group 1 and 13.7% in group 2 (p = 0.962). Conclusion Both therapies seemed equally efficacious in preventing endometriosis-related chronic pelvic pain recurrence in the first 9 months of follow-up

    Structure and magnetism of electrospun porous high-entropy (Cr1/5Mn1/5Fe1/5Co1/5Ni1/5)3O4, (Cr1/5Mn1/5Fe1/5Co1/5Zn1/5)3O4 and (Cr1/5Mn1/5Fe1/5Ni1/5Zn1/5)3O4 spinel oxide nanofibers

    Get PDF
    High-entropy oxide nanofibers, based on equimolar (Cr,Mn,Fe,Co,Ni), (Cr,Mn,Fe,Co,Zn) and (Cr,Mn,Fe,Ni,Zn) combinations, were prepared by electrospinning followed by calcination. The obtained hollow nanofibers exhibited a porous structure consisting of interconnected nearly strain-free (Cr1/5Mn1/5Fe1/5Co1/5Ni1/5)3O4, (Cr1/5Mn1/5Fe1/5Co1/5Zn1/5)3O4 and (Cr1/5Mn1/5Fe1/5Ni1/5Zn1/5)3O4 single crystals with a pure Fd3̄m spinel structure. Oxidation state of the cations at the nanofiber surface was assessed by X-ray photoelectron spectroscopy and cation distributions were proposed satisfying electroneutrality and optimizing octahedral stabilization. The magnetic data are consistent with a distribution of cations that satisfies the energetic preferences for octahedral vs. tetrahedral sites and is random only within the octahedral and tetrahedral sublattices. The nanofibers are ferrimagnets with relatively low critical temperature more similar to cubic chromites and manganites than to ferrites. Replacing the magnetic cations Co or Ni with non-magnetic Zn lowers the critical temperature from 374 K (Cr,Mn,Fe,Co,Ni) to 233 and 105 K for (Cr,Mn,Fe,Ni,Zn) and (Cr,Mn,Fe,Co,Zn), respectively. The latter nanofibers additionally have a low temperature transition to a reentrant spin-glass-like state

    El abordaje de la violencia en la escuela: el tránsito de lo imposible a lo posible desde la construcción de nuevas lógicas de subjetivación

    Get PDF
    Hoy las instituciones educativas son regidas por lógicas análogas a las que ordenan lo colectivo. Durante estas últimas décadas, se han desplegado cambios culturales significativos que han atravesado a dos agentes esenciales en los procesos de socialización: la familia y la escuela. Transitamos así por escenarios escolares donde sus actores se enfrentan desconcertados y perplejos a episodios diversos de violencia que acontecen, resultándoles dificultoso plantear matices o alguna perspectiva de cambio; quedando como única alternativa posible no abordarlo y acallarlo mediante la exclusión de estos alumnos del grupo a través de su aislamiento, expulsión o su medicalización. Proponemos acercarles el recorrido realizado por los miembros del Equipo Orientador de un Establecimiento Educativo de la Ciudad de San Luis que con el propósito de buscar asesoramiento para referenciar los modos de comprender y de intervenir en estas instancias, articuló sus demandas con los objetivos propuestos por el Proyecto de Extensión: «La violencia y la escuela» de la Facultad de Ciencias Humanas de la Universidad Nacional de San Luis, los cuales son: (1) Promover acciones que permitan identificar y analizar desde una perspectiva teórica y clínica, la lógica que da lugar a los actos violentos en los alumnos dentro de esta escuela. (2) Detectar situaciones concretas de actos violentos que operan sobre el grupo de alumnos que constituyen dicha muestra.(3) Generar la construcción de lazos sociales para favorecer la resolución de conflictos mediante el dialogo y la escucha. (4) Implementar estrategias terapéuticas. Para ello, los destinatarios (alumnos, directivos, docentes y padres) son convocados a trabajar la problemática mediante actividades tales como: Conversatorios-Taller con estrategias disparadoras (film, casos, narraciones), Trabajo en pequeños grupos de alumnos, Administración del Autotest- Cisneros a los alumnos que conforman la muestra. Se concreta además la inclusión de dos miembros de la Institución en Estudio, como integrantes de este Proyecto con participación en actividades de Extensión e Investigación

    Charge Storage Mechanism in Electrospun Spinel-Structured High-Entropy (Mn0.2Fe0.2Co0.2Ni0.2Zn0.2)3O4 Oxide Nanofibers as Anode Material for Li-Ion Batteries

    Get PDF
    High-entropy oxides (HEOs) have emerged as promising anode materials for next-generation lithium-ion batteries (LIBs). Among them, spinel HEOs with vacant lattice sites allowing for lithium insertion and diffusion seem particularly attractive. In this work, electrospun oxygen-deficient (Mn,Fe,Co,Ni,Zn) HEO nanofibers are produced under environmentally friendly calcination conditions and evaluated as anode active material in LIBs. A thorough investigation of the material properties and Li+ storage mechanism is carried out by several analytical techniques, including ex situ synchrotron X-ray absorption spectroscopy. The lithiation process is elucidated in terms of lithium insertion, cation migration, and metal-forming conversion reaction. The process is not fully reversible and the reduction of cations to the metallic form is not complete. In particular, iron, cobalt, and nickel, initially present mainly as Fe3+, Co3+/Co2+, and Ni2+, undergo reduction to Fe0, Co0, and Ni0 to different extent (Fe < Co < Ni). Manganese undergoes partial reduction to Mn3+/Mn2+ and, upon re-oxidation, does not revert to the pristine oxidation state (+4). Zn2+ cations do not electrochemically participate in the conversion reaction, but migrating from tetrahedral to octahedral positions, they facilitate Li-ion transport within lattice channels opened by their migration. Partially reversible crystal phase transitions are observed
    corecore