88 research outputs found
Stationary states of a spherical Minority Game with ergodicity breaking
Using generating functional and replica techniques, respectively, we study
the dynamics and statics of a spherical Minority Game (MG), which in contrast
with a spherical MG previously presented in J.Phys A: Math. Gen. 36 11159
(2003) displays a phase with broken ergodicity and dependence of the
macroscopic stationary state on initial conditions. The model thus bears more
similarity with the original MG. Still, all order parameters including the
volatility can computed in the ergodic phases without making any
approximations. We also study the effects of market impact correction on the
phase diagram. Finally we discuss a continuous-time version of the model as
well as the differences between on-line and batch update rules. Our analytical
results are confirmed convincingly by comparison with numerical simulations. In
an appendix we extend the analysis of the earlier spherical MG to a model with
general time-step, and compare the dynamics and statics of the two spherical
models.Comment: 26 pages, 8 figures; typo correcte
Development of porous Ti6Al4V samples by microsphere sintering
Two differently sized microspheres were sintered at 1300° C and 1400° C from 2 to 8 h in stoneware, alumina, yttria and zirconia moulds. Selecting the appropriate material to be used as a mould remains a critical issue given titanium's high reactivity at elevated temperatures. Optimum mechanical properties were obtained when sintering the smallest microspheres in yttria-coated moulds. Stiffness of the samples was lower than 40% of that of the bulk solid material, which comes closer to that of human cortical bone. Open and interconnected porosity was observed in all the specimens. © 2011 Elsevier B.V. All rights reserved.The translation of this paper was funded by the Polytechnic University of Valencia and the Universitat Jaume I.Reig Cerdå, L.; Amigó Borrås, V.; Busquets Mataix, DJ.; Calero Martinez, JA. (2012). Development of porous Ti6Al4V samples by microsphere sintering. Journal of Materials Processing Technology. 212(1):3-7. https://doi.org/10.1016/j.jmatprotec.2011.06.026S37212
Probing the immune responses to nanoparticles across environmental species. A perspective of the EU Horizon 2020 project PANDORA
Understanding how engineered nanomaterials affect immune responses of living organisms requires a strong collaborative effort between immunologists, toxicologists, ecologists, physiologists, inorganic chemists, nanomaterial scientists and experts in law and risk management. This perspective aims to provide a new viewpoint on the interaction between engineered nanomaterials and the immune defensive systems across living species, gained within the EU Horizon 2020 project PANDORA. We consider the effects of nanoparticle exposure on immune functions in plants, marine and terrestrial invertebrates and their relation to the current state of knowledge for vertebrates (in particular humans). These studies can shed light on the broader perspective of defensive and homeostatic mechanisms (immunity, inflammation, stress responses, microbiota, stem cell differentiation) suggesting ways to: i) perform a comparative analysis of the nanoparticle impact on immunity across model organisms; ii) inspire best practices in experimental methodologies for nanosafety/nanotoxicity studies; iii) regroup and harmonise fragmented research activities; iv) improve knowledge transfer strategies and nano-security; v) propose innovative tools and realistic solutions, thereby helping in identifying future research needs and tackling their challenges
Human Albumin Impairs Amyloid ÎČ-peptide Fibrillation Through its C-terminus: From docking Modeling to Protection Against Neurotoxicity in Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative process characterized by the accumulation of extracellular deposits of amyloid ÎČ-peptide (AÎČ), which induces neuronal death. Monomeric AÎČ is not toxic but tends to aggregate into ÎČ-sheets that are neurotoxic. Therefore to prevent or delay AD onset and progression one of the main therapeutic approaches would be to impair AÎČ assembly into oligomers and fibrils and to promote disaggregation of the preformed aggregate. Albumin is the most abundant protein in the cerebrospinal fluid and it was reported to bind AÎČ impeding its aggregation. In a previous work we identified a 35-residue sequence of clusterin, a well-known protein that binds AÎČ, that is highly similar to the C-terminus (CTerm) of albumin. In this work, the docking experiments show that the average binding free energy of the CTerm-AÎČ1â42 simulations was significantly lower than that of the clusterin-AÎČ1â42 binding, highlighting the possibility that the CTerm retains albumin's binding properties. To validate this observation, we performed in vitro structural analysis of soluble and aggregated 1âŻÎŒM AÎČ1â42 incubated with 5âŻÎŒM CTerm, equimolar to the albumin concentration in the CSF. Reversed-phase chromatography and electron microscopy analysis demonstrated a reduction of AÎČ1â42 aggregates when the CTerm was present. Furthermore, we treated a human neuroblastoma cell line with soluble and aggregated AÎČ1â42 incubated with CTerm obtaining a significant protection against AÎČ-induced neurotoxicity. These in silico and in vitro data suggest that the albumin CTerm is able to impair AÎČ aggregation and to promote disassemble of AÎČ aggregates protecting neurons
Immigrant IBD Patients in Spain Are Younger, Have More Extraintestinal Manifestations and Use More Biologics Than Native Patients
BackgroundPrevious studies comparing immigrant ethnic groups and native patients with IBD have yielded clinical and phenotypic differences. To date, no study has focused on the immigrant IBD population in Spain. MethodsProspective, observational, multicenter study comparing cohorts of IBD patients from ENEIDA-registry who were born outside Spain with a cohort of native patients. ResultsWe included 13,524 patients (1,864 immigrant and 11,660 native). The immigrants were younger (45 +/- 12 vs. 54 +/- 16 years, p < 0.001), had been diagnosed younger (31 +/- 12 vs. 36 +/- 15 years, p < 0.001), and had a shorter disease duration (14 +/- 7 vs. 18 +/- 8 years, p < 0.001) than native patients. Family history of IBD (9 vs. 14%, p < 0.001) and smoking (30 vs. 40%, p < 0.001) were more frequent among native patients. The most prevalent ethnic groups among immigrants were Caucasian (41.5%), followed by Latin American (30.8%), Arab (18.3%), and Asian (6.7%). Extraintestinal manifestations, mainly musculoskeletal affections, were more frequent in immigrants (19 vs. 11%, p < 0.001). Use of biologics, mainly anti-TNF, was greater in immigrants (36 vs. 29%, p < 0.001). The risk of having extraintestinal manifestations [OR: 2.23 (1.92-2.58, p < 0.001)] and using biologics [OR: 1.13 (1.0-1.26, p = 0.042)] was independently associated with immigrant status in the multivariate analyses. ConclusionsCompared with native-born patients, first-generation-immigrant IBD patients in Spain were younger at disease onset and showed an increased risk of having extraintestinal manifestations and using biologics. Our study suggests a featured phenotype of immigrant IBD patients in Spain, and constitutes a new landmark in the epidemiological characterization of immigrant IBD populations in Southern Europe
Diagnosis and management of glutaric aciduria type I â revised recommendations
Glutaric aciduria type I (synonym, glutaric acidemia type I) is a rare organic aciduria. Untreated patients characteristically develop dystonia during infancy resulting in a high morbidity and mortality. The neuropathological correlate is striatal injury which results from encephalopathic crises precipitated by infectious diseases, immunizations and surgery during a finite period of brain development, or develops insidiously without clinically apparent crises. Glutaric aciduria type I is caused by inherited deficiency of glutaryl-CoA dehydrogenase which is involved in the catabolic pathways of L-lysine, L-hydroxylysine and L-tryptophan. This defect gives rise to elevated glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine which can be detected by gas chromatography/mass spectrometry (organic acids) or tandem mass spectrometry (acylcarnitines). Glutaric aciduria type I is included in the panel of diseases that are identified by expanded newborn screening in some countries. It has been shown that in the majority of neonatally diagnosed patients striatal injury can be prevented by combined metabolic treatment. Metabolic treatment that includes a low lysine diet, carnitine supplementation and intensified emergency treatment during acute episodes of intercurrent illness should be introduced and monitored by an experienced interdisciplinary team. However, initiation of treatment after the onset of symptoms is generally not effective in preventing permanent damage. Secondary dystonia is often difficult to treat, and the efficacy of available drugs cannot be predicted precisely in individual patients. The major aim of this revision is to re-evaluate the previous diagnostic and therapeutic recommendations for patients with this disease and incorporate new research findings into the guideline
Risk Factors for COVID-19 in Inflammatory Bowel Disease: A National, ENEIDA-Based CaseâControl Study (COVID-19-EII)
(1) Scant information is available concerning the characteristics that may favour the acquisition of COVID-19 in patients with inflammatory bowel disease (IBD). Therefore, the aim of this study was to assess these differences between infected and noninfected patients with IBD. (2) This nationwide case-control study evaluated patients with inflammatory bowel disease with COVID-19 (cases) and without COVID-19 (controls) during the period March-July 2020 included in the ENEIDA of GETECCU. (3) A total of 496 cases and 964 controls from 73 Spanish centres were included. No differences were found in the basal characteristics between cases and controls. Cases had higher comorbidity Charlson scores (24% vs. 19%; p = 0.02) and occupational risk (28% vs. 10.5%; p < 0.0001) more frequently than did controls. Lockdown was the only protective measure against COVID-19 (50% vs. 70%; p < 0.0001). No differences were found in the use of systemic steroids, immunosuppressants or biologics between cases and controls. Cases were more often treated with 5-aminosalicylates (42% vs. 34%; p = 0.003). Having a moderate Charlson score (OR: 2.7; 95%CI: 1.3-5.9), occupational risk (OR: 2.9; 95%CI: 1.8-4.4) and the use of 5-aminosalicylates (OR: 1.7; 95%CI: 1.2-2.5) were factors for COVID-19. The strict lockdown was the only protective factor (OR: 0.1; 95%CI: 0.09-0.2). (4) Comorbidities and occupational exposure are the most relevant factors for COVID-19 in patients with IBD. The risk of COVID-19 seems not to be increased by immunosuppressants or biologics, with a potential effect of 5-aminosalicylates, which should be investigated further and interpreted with caution
Stratification in systemic sclerosis according to autoantibody status versus skin involvement: a study of the prospective EUSTAR cohort
Background: The current subclassification of systemic sclerosis into cutaneous subtypes does not fully capture the heterogeneity of the disease. We aimed to compare the performances of stratification into LeRoy's cutaneous subtypes versus stratification by autoantibody status in systemic sclerosis. Methods: For this cohort study, we assessed people with systemic sclerosis in the multicentre international European Scleroderma Trials and Research (EUSTAR) database. Individuals positive for systemic-sclerosis autoantibodies of two specificities were excluded, and remaining individuals were classified by cutaneous subtype, according to their systemic sclerosis-specific autoantibodies, or both. We assessed the performance of each model to predict overall survival, progression-free survival, disease progression, and different organ involvement. The three models were compared by use of the area under the curve (AUC) of the receiver operating characteristic and the net reclassification improvement (NRI). Missing data were imputed. Findings: We assessed the database on July 26, 2019. Of 16 939 patients assessed for eligibility, 10 711 patients were included: 1647 (15·4%) of 10 709 were male, 9062 (84·6%) were female, mean age was 54·4 (SD 13·8) years, and mean disease duration was 7·9 (SD 8·2) years. Information regarding cutaneous subtype was available for 10 176 participants and antibody data were available for 9643 participants. In the prognostic analysis, there was no difference in AUC for overall survival (0·82, 95% CI 0·81-0·84 for cutaneous only vs 0·84, 0·82-0·85 for antibody only vs 0·84, 0·83-0·86 for combined) or for progression-free survival (0·70, 0·69-0·71 vs 0·71, 0·70-0·72 vs 0·71, 0·70-0·72). However, at 4 years the NRI showed substantial improvement for the antibody-only model compared with the cutaneous-only model in prediction of overall survival (0·57, 0·46-0·71 for antibody only vs 0·29, 0·19-0·39 for cutaneous only) and disease progression (0·36, 0·29-0·46 vs 0·21, 0·14-0·28). The antibody-only model did better than the cutaneous-only model in predicting renal crisis (AUC 0·72, 0·70-0·74 for antibody only vs 0·66, 0·64-0·69 for cutaneous only) and lung fibrosis leading to restrictive lung function (AUC 0·76, 0·75-0·77 vs 0·71, 0·70-0·72). The combined model improved the prediction of digital ulcers and elevated systolic pulmonary artery pressure, but did poorly for cardiac involvement. Interpretation: The autoantibody-only model outperforms cutaneous-only subsetting for risk stratifying people with systemic sclerosis in the EUSTAR cohort. Physicians should be aware of these findings at the time of decision making for patient management. Funding: World Scleroderma Foundation
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