2,535 research outputs found

    The IGN-E case: Integrating through a hidden ontology

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    National Geographic Institute of Spain (IGN-E) wanted to integrate its main information sources for building a common vocabulary reference and thus to manage the huge amount of information it held. The main problem of this integration is the great heterogeneity of data sources. The Ontology Engineering Group (OEG) is working with IGN-E to attain this objective in two phases: first, by creating automatically an ontology using the semantics of catalogues sections, and second, by discovering mappings automatically that can relate ontology concepts to database instances. So, these mappings are the instruments to break the syntactic, semantic and granularity heterogeneity gap. We have developed software for building a first ontology version and for discovering automatically mappings using techniques that take into account all types of heterogeneity. The ontology contains a set of extra-attributes which are identified in the building process. The ontology, called PhenomenOntology, will be reviewed by domain experts of IGN-E. The automatic mapping discovery will be also used for discovering new knowledge that will be added to the ontology. For increasing the usability and giving independence to different parts, the processes of each phase will be designed automatically and as upgradeable as possible

    Incidence of myopia in Swedish schoolchildren: A longitudinal study

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    Purpose: The prevalence of myopia in Scandinavia tends to be lower than in other parts of the world. This study aimed to investigate the incidence of myopia and its predictors in Swedish children to characterise this trend. Methods: A 2-year longitudinal study was conducted following a cohort of schoolchildren aged 8–16 years. Myopia was defined as a spherical equivalent refraction (SER) ≤ −0.50 D. The study enrolled 128 participants, 70 (55%) females with a mean age of 12.0 years (SD = 2.4). Results: The cumulative incidence of myopia during the follow-up period was 5.5%, and the incidence rate of myopia was 3.2 cases per 100 person-years. Participants with myopia at baseline exhibited a faster increase in refractive error during the follow-up period. Likewise, participants with two myopic parents exhibited a more marked change towards myopia, regardless of their initial refractive error. Conclusion: In the current study, similar to prevalence, the incidence of myopia was low when compared with other parts of the world. These results lead us to formulate a new hypothesis that the normal emmetropisation process may be protected by low educational pressure practised in Sweden during early childhood. Further research is necessary to test this new hypothesis. © 2024 The Author(s). Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists.This study was supported by Specsavers Sweden AB, the faculty of Health and Life Sciences, Linnaeus University and the Brien Holden Vision Institute

    Effect of the dispersion state of minerals on the properties of cellulose nanofiber-based composite films

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    The dispersion state and the efficiency of the mixture of the different components in a composite film have an important impact on its mechanical and optical properties. In the present work, the impacts of different dispersion treatments on the disaggregation state of fibrous clay particles in water, and on the properties of related cellulose nanofiber (CNF)-based composite films, were evaluated. X-ray diffraction studies, performed on samples of sepiolite and palygorskite, revealed only minor changes in the diffraction pattern when the minerals were subjected to ultrasonic treatment, with or without the addition of different chemical dispersing agents. Conversely, microscopic studies revealed important differences in the dispersion state of the samples, induced by the addition of the different dispersants, showing an improvement in the disaggregation of the mineral crystals. The composite films prepared with sepiolite (and carboxymethylcellulose, as chemical dispersant) dispersed using ultrasonic treatment, and different types of CNF, showed improved optical and mechanical properties when compared with composites of the same counterparts prepared with sepiolite dispersed using a high-speed shear disperser.info:eu-repo/semantics/publishedVersio

    Percutaneous Closure of Atrial Septal Defects: a Decade of Experience at a Reference Center

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    INTRODUCTION: Atrial septal defects (ASD) are among the most common congenital anomalies and account for 10% of congenital heart disease in the pediatric age-group and 30% in adults. Closure is indicated when there is evidence of hemodynamic significance or after a paradoxical embolic event. Ten years ago, percutaneous closure became the treatment of choice in our center for all patients with a clear indication and favorable anatomy. In this paper we report the experience of this first decade. OBJECTIVE: To assess the short- and long-term results of our ten-year experience with percutaneous closure of atrial septal defects. METHODS: We studied retrospectively all patients with ASD treated with a percutaneous approach between November 1998 and December 2008. The pediatric age-group consisted of patients younger than 19 years old. Demographic data, clinical indications, minor and major complication rates, success rate and long-term outcome were assessed. RESULTS: In the first ten years of experience 510 patients, of whom 166 were in the pediatric group, were treated in our center by a team of adult and pediatric cardiologists. The overall success rate of the procedure was 98% (97.5% in ASD and 99.5% in patent foramen ovale (PFO). The minor complication rate was 3% (3.4% in ASD and 2% in PFO). The most frequent complication was supraventricular tachycardia. The major complication rate was 1.2% (0.6% in ASD and 2% in PFO). Two patients developed cardiac tamponade due to hemopericardium that was resolved by pericardiocentesis, without need for surgery. One patient had an arterial pseudoaneurysm corrected by vascular surgery. There was no device embolization and no need for urgent surgery in this population. During follow-up two patients had recurrence of ischemic stroke, one had a transient ischemic attack and another had a hemorrhagic stroke. Mortality was 0.6% (0.6% in ASD and 0.5% in PFO). There were no in-hospital deaths. During follow-up there were two deaths, both in the adult group. DISCUSSION AND CONCLUSION: In this population the success rate was high and most of the complications were minor. The results of this collaboration between adult and pediatric cardiologists in the first ten years of activity confirm the safety and efficacy of percutaneous closure of septal defects, when there is careful patient selection and a standardized technique

    Tuberculosis screening in patients receiving biological therapy

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    AIM: Biological therapies are a risk factor for tuberculosis (TB). Portuguese recommendations recommend universal baseline screening for TB before starting biologics (2006) and annually thereafter if screened negative (2012 update). The gain with re-screening remains unknown. We aimed to i)identify the risk of latent TB infection at baseline screening among patients candidates to initiate biologics ii)present follow-up results for patients receiving different biological therapies and analyse intolerance or toxicity related to preventive therapy, conversions of immunodiagnostic tests under biological therapy and development of active TB. METHODS: Patients screened for TB at a reference centre before starting biological therapy between 2008-2012 were identified. Medical files were retrospectively reviewed. Demographic data, screening and follow-up results and information on biological therapy were collected. EXCLUSION CRITERIA: unavailable information on initiation of biological therapy. RESULTS: 183 patients were included in the study, with 115 starting biological therapy. The baseline screening was positive in 52(45,2%) patients - 50(96,2%) were proposed for preventive treatment (2 had abnormal liver enzymes). Mild hepatotoxicity occurred in 4(8%) patients without need to interrupt TB prophylaxis. No cases of active TB occurred during follow-up in patients with positive baseline screening. Among the 63(54,8%) patients who screened negative, 2(3,2%) developed active TB (under infliximab and adalimumab) more than one year after initiation of biologics. 26(41,3%) patients were re-screened at the TB centre. 5(19,2%) had tuberculin skin test (TST) conversion and one concomitantly undetermined IGRA. No IGRA conversions were observed. The follow-up period was 4,0 years. TB baseline screening's negative predictive value (NPV) was 96,8% (95%CI: 89,0% to 99.5%). A low rate of re-screening was observed. CONCLUSION: The rate of latent TB at baseline screening was higher than expected. Preventive treatment was well tolerated. No patients with positive baseline screening developed active TB. Efforts should be made to raise awareness concerning the risk of TB exposure, specially considering that the active TB cases were compatible with new infection. The rate of re-screening suggests a low awareness regarding current recommendations Nation-wide studies are necessary to evaluate the efficacy of the re-screening strategy and to clarify what risk groups most benefit from it

    Extraction of fact tables from a relational database: an effort to establish rules in denormalization

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    Relational databases are supported by very well established models. However, some neglected problems can occur with the join operator: semantic mistakes caused by the multiple access path problem and faults when connection traps arise. In this paper we intend to identify and overcome those problems and to establish rules for relational data denormalization. Two denormalization forms are proposed and a case study is presented.info:eu-repo/semantics/publishedVersio

    Stroke and Cardiac Papillary Fibroelastoma: Mechanical Thrombectomy after Thrombolytic Therapy

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    We describe a case of a 34-year-old man with a sudden development of right hemiparesis and aphasia because of infarction of the left middle cerebral artery that was submitted to intravenous (IV) recombinant tissue plasminogen activator and mechanical thrombectomy. Transesophageal echocardiogram showed a small mass on the anterior leaflet of the mitral valve. Cardiac surgery was performed, and histological examination of the removed material was consistent with cardiac papillary fibroelastoma (CPF). Experience in using IV thrombolysis for the treatment of embolic stroke because of CPF is limited. To the best of our knowledge, only 3 patients are reported in literature in whom acute ischemic stroke and associated CPF were treated with thrombolytic therapy. A discussion of the efficacy of IV thrombolysis and the possible superiority of mechanical thrombectomy is included

    Usefulness of Tissue Doppler Imaging to Predict Arrhythmic Events in Adults with Repaired Tetralogy of Fallot

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    INTRODUCTION: Adults with repaired tetralogy of Fallot (TOF) may be at risk for progressive right ventricular (RV) dilatation and dysfunction, which is commonly associated with arrhythmic events. In frequently volume-overloaded patients with congenital heart disease, tissue Doppler imaging (TDI) is particularly useful for assessing RV function. However, it is not known whether RV TDI can predict outcome in this population. OBJECTIVE: To evaluate whether RV TDI parameters are associated with supraventricular arrhythmic events in adults with repaired TOF. METHODS: We studied 40 consecutive patients with repaired TOF (mean age 35 +/- 11 years, 62% male) referred for routine echocardiographic exam between 2007 and 2008. The following echocardiographic measurements were obtained: left ventricular (LV) ejection fraction, LV end-systolic volume, LV end-diastolic volume, RV fractional area change, RV end-systolic area, RV end-diastolic area, left and right atrial volumes, mitral E and A velocities, RV myocardial performance index (Tei index), tricuspid annular plane systolic excursion (TAPSE), myocardial isovolumic acceleration (IVA), pulmonary regurgitation color flow area, TDI basal lateral, septal and RV lateral peak diastolic and systolic annular velocities (E' 1, A' 1, S' 1, E' s, A' s, S' s, E' rv, A' rv, S' rv), strain, strain rate and tissue tracking of the same segments. QRS duration on resting ECG, total duration of Bruce treadmill exercise stress test and presence of exercise-induced arrhythmias were also analyzed. The patients were subsequently divided into two groups: Group 1--12 patients with previous documented supraventricular arrhythmias (atrial tachycardia, fibrillation or flutter) and Group 2 (control group)--28 patients with no previous arrhythmic events. Univariate and multivariate analysis was used to assess the statistical association between the studied parameters and arrhythmic events. RESULTS: Patients with previous events were older (41 +/- 14 vs. 31 +/- 6 years, p = 0.005), had wider QRS (173 +/- 20 vs. 140 +/- 32 ms, p = 0.01) and lower maximum heart rate on treadmill stress testing (69 +/- 35 vs. 92 +/- 9%, p = 0.03). All patients were in NYHA class I or II. Clinical characteristics including age at corrective surgery, previous palliative surgery and residual defects did not differ significantly between the two groups. Left and right cardiac chamber dimensions and ventricular and valvular function as evaluated by conventional Doppler parameters were also not significantly different. Right ventricular strain and strain rate were similar between the groups. However, right ventricular myocardial TDI systolic (Sa: 5.4+2 vs. 8.5 +/- 3, p = 0.004) and diastolic indices and velocities (Ea, Aa, septal E/Ea, and RV free wall tissue tracking) were significantly reduced in patients with arrhythmias compared to the control group. Multivariate linear regression analysis identified RV early diastolic velocity as the sole variable independently associated with arrhythmic history (RV Ea: 4.5 +/- 1 vs. 6.7 +/- 2 cm/s, p = 0.01). A cut-off for RV Ea of < 6.1 cm/s identified patients in the arrhythmic group with 86% sensitivity and 59% specificity (AUC = 0.8). CONCLUSIONS: Our results suggest that TDI may detect RV dysfunction in patients with apparently normal function as assessed by conventional echocardiographic parameters. Reduction in RV early diastolic velocity appears to be an early abnormality and is associated with occurrence of arrhythmic events. TDI may be useful in risk stratification of patients with repaired tetralogy of Fallot

    Green Production of Anionic Surfactant Obtained from Pea Protein

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    A pea protein isolate was hydrolyzed by a double enzyme treatment method in order to obtain short peptide sequences used as raw materials to produce lipopeptides-based surfactants. Pea protein hydrolysates were prepared using the combination of Alcalase and Flavourzyme. The influence of the process variables was studied to optimize the proteolytic degradation to high degrees of hydrolysis. The average peptide chain lengths were obtained at 3–5 amino acid units after a hydrolysis of 30 min with the mixture of enzymes. Then, N-acylation in water, in presence of acid chloride (C12 and C16), carried out with a conversion rate of amine functions of 90%, allowed to obtain anionic surfactant mixtures (lipopeptides and sodium fatty acids). These two steps were performed in water, in continuous and did not generate any waste. This process was therefore in line with green chemistry principles. The surface activities (CMC, foaming and emulsifying properties) of these mixtures were also studied. These formulations obtained from natural renewable resources and the reactions done under environmental respect, could replace petrochemical based surfactants for some applications
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