789 research outputs found
Analysis of the Damage Evolution in Steel Specimens under Tension by Means of XRCT
When a steel specimen is tested under tension, damage usually develops evenly all along the specimen, finally necking and leading to the typical cup-cone fracture surface. Nevertheless, some steels present an unusual fracture pattern consisting on a plane fracture surface with a dark region in the centre of the fracture zone. In this contribution, the authors analyse the evolution of the internal damage by using X-ray computed tomography (XRCT) on 3mm-diametre specimens of two steels. The specimens are tested in subsequent loading steps, after each of which it is unloaded and analysed with XRCT. This procedure helps to identify the evolution of damage developed inside each specimen at predefined strain levels. XRCT reveals a very high initial porosity in the material with the cup-cone fracture pattern and a very low initial porosity in the other. In the latter, fracture is triggered by a concentrated internal damage that can be seen as an internal notch which produces a stress concentration that leads to the eventual failure
Formation and emission properties of single InGaAs/GaAs quantum dots and pairs grown by droplet epitaxy
Trabajo presentado a la 30th International Conference on the Physics of Semiconductors, celebrada en Seul (Korea) del 25 al 30 de Julio de 2010.The emission properties of lateral and vertical QD pairs grown on GaAs nanoholes are investigated. Vertical QD pairs with different size asymmetry have been fabricated controlling the bottom QD size independently of the areal density. The emission of individual pairs is dominated by spectral diffusion effects and charge instabilities induced by the local charge environment. Lateral QD pairs have been fabricated on GaAs nanoholes and studied as a function of an electric field applied in the growth plane.Peer Reviewe
La dirección de centros educativos en Iberoamérica : reflexiones y experiencias
La presente aportación recoge la visión de más de veinticinco especialistas de doce países iberoamericanos sobre aspectos de la dirección de centros educativos. Su presentación exige unas reflexiones tanto sobre la temática como sobre el contenido. En relación con la temática, la dirección, entendida como sistema de dinamización, apoyo y acompañamiento a la actuación pedagógica e institucional, lejos de estar en crisis, se considera cada vez más necesaria. Los centros de formación y los profesores se enfrentan a situaciones nuevas, diversas y complejas, consecuencia de una realidad más dinámica, de una sociedad más exigente y de unos usuarios más conscientes de la calidad de servicios que precisan. La nueva situación hace pertinente que las respuestas educativas tengan en cuenta la complejidad de los fenómenos y sean diferenciadas en función del contexto y de los destinatarios, resaltando la necesidad y conveniencia de toma de decisiones fundamentadas y de apoyos vinculados a su desarrollo. El desarrollo de la temática de dirección que se aborda en el presente texto recoge aportaciones de diversa naturaleza. Por una parte, aquellas que han venido trabajando cuatro equipos con profesionales de diferentes países durante seis meses; por otra, recoge otras tres complementarias realizadas también por equipos de especialistas. Su realización se vincula al encuentro de especialistas de la Red de Apoyo a la Gestión Educativa (Red AGE: http://www.redage.org) realizado en el mes de junio de 2010 en la ciudad de Santiago de Chile. Allí, los representantes de las organizaciones miembro presentaron y debatieron sobre la situación actual de la dirección escolar en sus respectivos países, que constituyen la base sobre la que se han realizado las aportaciones definitivas que recoge el presente texto. Se cubre así un propósito fundamental de la Red AGE, como es el de fomentar el intercambio de experiencias, la profesionalización de los directivos y la promoción del conocimiento sobre administración y gestión educativa. La finalidad última es la de mejorar el funcionamiento de las instituciones formativas (y, a través de ellas, de los sistemas formativos), procurando sean de calidad y un instrumento para el cambio profesional y social
Romosozumab (sclerostin monoclonal antibody) versus teriparatide in postmenopausal women with osteoporosis transitioning from oral bisphosphonate therapy : a randomised, open-label, phase 3 trial
Background: Previous bisphosphonate treatment attenuates the bone-forming effect of teriparatide. We compared the effects of 12 months of romosozumab (AMG 785), a sclerostin monoclonal antibody, versus teriparatide on bone mineral density (BMD) in women with postmenopausal osteoporosis transitioning from bisphosphonate therapy.
Methods: This randomised, phase 3, open-label, active-controlled study was done at 46 sites in North America, Latin America, and Europe. We enrolled women (aged >= 55 to <= 90 years) with postmenopausal osteoporosis who had taken an oral bisphosphonate for at least 3 years before screening and alendronate the year before screening; an areal BMD T score of -2.5 or lower at the total hip, femoral neck, or lumbar spine; and a history of fracture. Patients were randomly assigned (1:1) via an interactive voice response system to receive subcutaneous romosozumab (210 mg once monthly) or subcutaneous teriparatide (20 mu g once daily). The primary endpoint was percentage change from baseline in areal BMD by dual-energy x-ray absorptiometry at the total hip through month 12 (mean of months 6 and 12), which used a linear mixed effects model for repeated measures and represented the mean treatment effect at months 6 and 12. All randomised patients with a baseline measurement and at least one post-baseline measurement were included in the efficacy analysis. This trial is registered with ClinicalTrials.gov, number NCT01796301.
Findings: Between Jan 31, 2013, and April 29, 2014, 436 patients were randomly assigned to romosozumab (n=218) or teriparatide (n=218). 206 patients in the romosozumab group and 209 in the teriparatide group were included in the primary efficacy analysis. Through 12 months, the mean percentage change from baseline in total hip areal BMD was 2.6% (95% CI 2.2 to 3.0) in the romosozumab group and -0.6% (-1.0 to -0.2) in the teriparatide group; difference 3.2% (95% CI 2.7 to 3.8; p<0.0001). The frequency of adverse events was generally balanced between treatment groups. The most frequently reported adverse events were nasopharyngitis (28 [13%] of 218 in the romosozumab group vs 22 [10%] of 214 in the teriparatide group), hypercalcaemia (two [<1%] vs 22 [10%]), and arthralgia (22 [10%] vs 13 [6%]). Serious adverse events were reported in 17 (8%) patients on romosozumab and in 23 (11%) on teriparatide; none were judged treatment related. There were six (3%) patients in the romosozumab group compared with 12 (6%) in the teriparatide group with adverse events leading to investigational product withdrawal.
Interpretation: Transition to a bone-forming agent is common practice in patients treated with bisphosphonates, such as those who fracture while on therapy. In such patients, romosozumab led to gains in hip BMD that were not observed with teriparatide. These data could inform clinical decisions for patients at high risk of fracture
Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: An international case-cohort study
We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts.A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κw). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index.A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κw=0.65, IQR 0.53–0.72, p less than 0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κw=0.54, IQR 0.45–0.64, p less than 0.0001). The prognostic accuracy of academic physicians with greater than 20 years of experience (C-index=0.72, IQR 0.0–0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70–0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72–0.75).Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts
Adherence and Toxicity during the Treatment of Latent Tuberculous Infection in a Referral Center in Spain
Latent tuberculosis infection; Toxicity; Tuberculosis screeningInfecció tuberculosa latent; Toxicitat; Cribratge de tuberculosiInfección tuberculosa latente; Toxicidad; Cribado de tuberculosisThe screening and treatment of latent tuberculosis infection (LTBI) in countries with a low incidence of TB is a key strategy for the elimination of tuberculosis (TB). However, treatment can result in adverse events (AEs) and have poor adherence. This study aimed to describe treatment outcomes and AEs for LTBI patients at two departments in Vall d'Hebron University Hospital in Barcelona, Spain. A retrospective study was conducted on all persons treated for LTBI between January 2018 and December 2020. Variables collected included demographics, the reason for LTBI screening and treatment initiation, AEs related to treatment, and treatment outcome. Out of 261 persons who initiated LTBI treatment, 145 (55.6%) were men, with a median age of 42.1 years. The indications for LTBI screening were household contact of a TB case in 96 (36.8%) persons, immunosuppressive treatment in 84 (32.2%), and recently arrived migrants from a country with high TB incidence in 81 (31.0%). Sixty-three (24.1%) persons presented at least one AE during treatment, and seven (2.7%) required definitive discontinuation of treatment. In the multivariate analysis, AE development was more frequent in those who started LTBI treatment due to immunosuppression. Overall, 226 (86.6%) completed treatment successfully. We concluded that LTBI screening and treatment groups had different risks for adverse events and treatment outcomes. Persons receiving immunosuppressive treatment were at higher risk of developing AEs, and recently arrived immigrants from countries with a high incidence of TB had greater LTFU. A person-centered adherence and AE management plan is recommended.A.M.L. was supported by a postdoctoral grant “Juan Rodés” (JE21/00027) from the Instituto de Salud Carlos through the Ministry of Economy and Competitiveness, Spain
Integrating Clinical Probability into the Diagnostic Approach to Idiopathic Pulmonary Fibrosis: An International Working Group Perspective
Background. When considering the diagnosis of idiopathic pulmonary fibrosis (IPF), experienced
clinicians integrate clinical features that help to differentiate IPF from other fibrosing interstitial lung
diseases, thus generating a “pre-test” probability of IPF. The aim of this international working group
perspective was to summarize these features using a tabulated approach similar to chest HRCT and
histopathologic patterns reported in the international guidelines for the diagnosis of IPF, and to help
formally incorporate these clinical likelihoods into diagnostic reasoning to facilitate the diagnosis of
IPF.
Methods. The committee group identified factors that influence the clinical likelihood of a diagnosis
of IPF, which was categorized as a pre-test clinical probability of IPF into “high” (70-100%),
“intermediate” (30-70%), or “low” (0-30%). After integration of radiological and histopathological
features, the post-test probability of diagnosis was categorized into “definite” (90-100%), “high
confidence” (70-89%), “low confidence” (51-69%), or “low” (0-50%) probability of IPF.
Findings. A conceptual Bayesian framework was created, integrating the clinical likelihood of IPF
(“pre-test probability of IPF”) with the HRCT pattern, the histopathology pattern when available,
and/or the pattern of observed disease behavior into a “post-test probability of IPF”. The diagnostic
probability of IPF was expressed using an adapted diagnostic ontology for fibrotic interstitial lung
diseases.
Interpretation. The present approach will help incorporate the clinical judgement into the diagnosis
of IPF, thus facilitating the application of IPF diagnostic guidelines and, ultimately improving
diagnostic confidence and reducing the need for invasive diagnostic techniques
Behavioral immune landscapes of inflammation.
Transcriptional or proteomic profiling of individual cells have revolutionized interpretation of biological phenomena by providing cellular landscapes of healthy and diseased tissues. These approaches, however, fail to describe dynamic scenarios in which cells can change their biochemical properties and downstream “behavioral” outputs every few seconds or minutes. Here, we used 4D live imaging to record tens to hundreds of morpho-kinetic parameters describing the dynamism of individual leukocytes at sites of active inflammation. By analyzing over 100,000 reconstructions of cell shapes and tracks over time, we obtained behavioral descriptors of individual cells and used these high-dimensional datasets to build behavioral landscapes. These landscapes recognized leukocyte identities in the inflamed skin and trachea, and inside blood vessels uncovered a continuum of neutrophil states, including a large, sessile state that was embraced by the underlying endothelium and associated with pathogenic inflammation. Behavioral in vivo screening of thousands of cells from 24 different mouse mutants identified the kinase Fgr as a driver of this pathogenic state, and genetic or pharmacological interference of Fgr protected from inflammatory injury. Thus, behavioral landscapes report unique biological properties of dynamic environments at high cellular, spatial and temporal resolution.pre-print4302 K
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