Combined creep and plastic analysis with numerical methods

The combination of plastic and creep analysis formulation are developed in this paper. The boundary element method and the finite element method are applied in plates in order to do the numerical analysis. This new approach is developed to combine the constitutive equation for time hardening creep and the constitutive equation for plasticity, which is based on the von Mises criterion and the Prandtl-Reuss flow. The implementation of creep strain in the formulation is achieved through domain integrals. The creep phenomenon takes place in the domain which is discretized into quadratic quadrilateral continuous and discontinuous cells. The creep analysis is applied to metals with a power law creep for the secondary creep stage. Results obtained for three models studied are compared to those published in the literature. The obtained results are in good agreement and evinced that the Boundary Element Method could be a suitable tool to deal with combined nonlinear problems

Functional brain networks reveal the existence of cognitive reserve and the interplay between network topology and dynamics

We investigated how the organization of functional brain networks was related to cognitive reserve (CR) during a memory task in healthy aging. We obtained the magnetoencephalographic functional networks of 20 elders with a high or low CR level to analyse the differences at network features. We reported a negative correlation between synchronization of the whole network and CR, and observed differences both at the node and at the network level in: the average shortest path and the network outreach. Individuals with high CR required functional networks with lower links to successfully carry out the memory task. These results may indicate that those individuals with low CR level exhibited a dual pattern of compensation and network impairment, since their functioning was more energetically costly to perform the task as the high CR group. Additionally, we evaluated how the dynamical properties of the different brain regions were correlated to the network parameters obtaining that entropy was positively correlated with the strength and clustering coefficient, while complexity behaved conversely. Consequently, highly connected nodes of the functional networks showed a more stochastic and less complex signal. We consider that network approach may be a relevant tool to better understand brain functioning in aging.Comment: Main manuscript: 23 pages including references, 20 pages text, 8 figures and supplementary information include

Use of simple noninvasive biomarkers to predict liver fibrosis in HIV/HCV coinfection in routine clinical practice

This study was supported by a grant from Abbott Laboratories. The authors wish to thank the Spanish Health Ministry (ISCIII-RETIC RD06/006) for financial support.Background Simple noninvasive tests to predict fibrosis, as an alternative to liver biopsy (LB), are needed. Of these, the aspartate aminotransferase (AST) to platelet ratio index (APRI) and the Forns index (FI) have been validated in HIV/hepatitis C virus (HCV) coinfection. However, these indexes may have lower diagnostic value in situations other than the circumscribed conditions of validation studies. We therefore examined the value of the APRI and FI in HIV/HCV-coinfected patients for the detection of significant fibrosis in real-life conditions. Patients and methods HIV/HCV-coinfected patients who had participated in a multicentre cross-sectional retrospective study were selected if they had undergone an LB within 24 months before the last visit. The predictive accuracy of the APRI and FI was measured using the areas under receiver-operating-characteristic curves (AUROCs). Diagnostic accuracy was determined using the positive (PPV) and negative (NPV) predictive values. Results A total of 519 coinfected individuals were included in the study. The AUROC [95% confidence interval (95% CI)] of the APRI was 0.67 (0.66–0.71) and that of the FI was 0.67 (0.62–0.71). The PPV of the APRI was 79% and its NPV was 66%. The PPV of the FI was 74% and its NPV was 64%. LB length was available and was ≥15 mm in 120 individuals. In this group, the PPV of the APRI was 85%, and that of the FI was 81%. Using these indexes, 22% of patients could be spared LB. Applying both models sequentially, 30% of patients could be spared LB. Conclusions In HIV/HCV-coinfected patients, the diagnostic accuracy of the APRI in real-life conditions was similar to that in the validation studies. The FI performed less well. However, combining the two indexes to make decisions on anti-HCV therapy may prevent a significant proportion of patients from having to undergo LB.Abbott LaboratoriesSpanish Health Ministry (ISCIII-RETIC RD06/006

Evolución energética de haces de rayos X empleados en radiología pediátrica, al interior de maniquís de PMMA, medida con TLD-300

El dosímetro termoluminiscente CaF2:Tm (TLD-300) presenta una curva de brillo característica con dos grupos de picos bien definidos en la zona de baja y alta temperatura. En nuestro laboratorio se ha estudiado la relación entre la señal de alta y baja temperatura (HTLR), de esta curva, con la energía efectiva de haces de fotones típicos de mamografía, obteniéndose el ajuste a una función empírica1. El objetivo de este trabajo es estudiar la evolución energética de haces de rayos X típicos de radiología pediátrica dentro de maniquís de PMMA, analizando la curva de brillo del TLD-300 y empleando la relación empírica previamente obtenid

Towards sustainable industrial development - a systems thinking-based approach

Various critical global issues, including global warming and poverty, have been recognized and identified by the United Nations (UN) as drivers for unsustainability. Consequently, the UN established the Sustainable Development Goals (SDGs) with the aim of seeking universal peace and larger freedom by balancing the three dimensions of sustainable development, i.e. economic, social and environmental. A particular attention SDGs pay is in eradicating poverty as this is considered one of the greatest global challenges. Poverty is not only an economic matter as it also has an impact on the social and environmental dimensions. A strategy to tackle poverty is to foster industry development. However, a holistic point of view is necessary by also considering stakeholders otherwise, it becomes a neoliberal solution. Despite the fact that some research has been conducted, e.g. case studies and surveys of sustainable practices, there is a lack of industrial sustainable development as a framework to tackle sustainability issues. Thus, this paper proposes a framework for industrial sustainable development under a socially inclusive approach within the context of the Mexican manufacturing industry. The framework proposal is based on a state-of-the-art literature review conducted in the Web of Science and Scopus databases.N/

El papel de la edad de inicio en el consumo problemático de alcohol: ¿artefacto o efecto de cohorte?

La edad de inicio se ha señalado como un predictor crucial del consumo de alcohol en la adolescencia. Sin embargo, varios autores han advertido que se trata de un artefacto poco fiable que se explica por la tendencia a retrasar la edad de inicio a medida que aumenta la edad de los encuestados (forward telescoping o sesgo de memoria). Este estudio pretende comprobar si la edad de inicio es una medida aproximativa de la edad o un predictor del consumo de alcohol por sí mismo. Se utilizó un modelo de regresión jerárquica y la Macro Process para SPSS para probar el efecto de la edad de inicio (controlando la edad) en el consumo de alcohol y el papel mediador/moderador de la edad de inicio, el control parental y el sexo en el consumo de alcohol, respectivamente. Los resultados confirman el papel de la edad de inicio como predictor significativo del consumo de alcohol en los adolescentes ecuatorianos en lugar de artefacto. Además, la edad de inicio medió completamente el efecto de la edad en el consumo de alcohol, con frecuencia moderado por el sexo. Se discuten posteriormente las implicaciones prácticas.Age of onset has been reported as a crucial predictor for alcohol consumption in adolescence. However, several authors have warned against it as an unreliable artefact accounted by the tendency to delay age of onset as respondents’ age increases (forward telescoping). This study aims to test whether age of onset is either a proxy for age or a predictor of alcohol consumption of its own. A hierarchical regression model and Process Macro for SPSS were used to test the effect of age of onset (controlling for age) on alcohol consumption and the mediating/moderator role of age of onset, parental control, and sex on alcohol consumption, respectively. Results support the role of age of onset as a significant predictor of alcohol consumption in Ecuadorian adolescents, rather than an artefact. Furthermore, age of onset completely mediated the effect of age on alcohol consumption, often moderated by sex. Practical implications are further discussed

Usefulness of analysis of cerebrospinal fluid for the diagnosis of neurotransmitters and pterin defects and glucose and folate transport deficiencies across blood brain barrier

Med Clin (Barc). 2006 Jun 17;127(3):81-5. [Usefulness of analysis of cerebrospinal fluid for the diagnosis of neurotransmitters and pterin defects and glucose and folate transport deficiencies across blood brain barrier] [Article in Spanish] Ormazabal A, García Cazorla A, Pérez Dueñas B, Pineda M, Ruiz A, López Laso E, García Silva M, Carilho I, Barbot C, Cormand B, Ribases M, Moller L, Fernández Alvarez E, Campistol J, Artuch R. Hospital Sant Joan de Déu, Esplugues, Barcelona, España. Abstract BACKGROUND AND OBJECTIVE: In the last few years, it has been described inborn errors of neurotransmitter and pterin metabolism and defects in folate and glucose transport across blood brain barrier. All these defects are classified as rare diseases and needs cerebrospinal fluid (CSF) sample analysis for diagnosis. Our aim was to evaluate the results of the application of a CSF analysis protocol in a pediatric population from Spain and Portugal presenting with neurological disorders of unknown origin. PATIENTS AND METHOD: We studied CSF samples from and 283 patients with neurological disorders of unknown origin and 127 controls. Neurotransmitters were analysed by HPLC with electrochemical detection, and pterins and 5-methyltetrahydrofolate were determined by HPLC with fluorescence detection. RESULTS: We diagnosed 3 patients with tyrosine hidroxylase deficiency, 2 with dopa responsive dystonia, 14 with GTP-ciclohydrolase deficiency, 2 with glucose transport deficiency and 43 with cerebral folate deficiency. CONCLUSIONS: This study allowed us to diagnose new patients, and more importantly, the establishment in all of them of a pharmacological or nutritional treatment. The most frequent defect found was CSF 5-methyltetrahydrofolate deficiency, which was present in different groups of patients. PMID: 16827996 [PubMed - indexed for MEDLINE

Energy-dense diets increase FGF23, lead to phosphorus retention and promote vascular calcifications in rats

Rats with normal renal function (Experiment 1, n = 12) and uninephrectomized (1/2Nx) rats (Experiment 2, n = 12) were fed diets with normal P (NP) and either normal (NF) or high fat (HF). Rats with intact renal function (Experiment 3, n = 12) were also fed NF or HF diets with high P (HP). Additionally, uremic (5/6Nx) rats (n = 16) were fed HP diets with NF or HF. Feeding the HF diets resulted in significant elevation of plasma FGF23 vs rats fed NF diets: Experiment 1, 593 ± 126 vs 157 ± 28 pg/ ml (p < 0.01); Experiment 2, 538 ± 105 vs 250 ± 18 pg/ml (p < 0.05); Experiment 3, 971 ± 118 vs 534 ± 40 pg/ml (p < 0.01). Rats fed HF diets showed P retention and decreased renal klotho (ratio klotho/actin) vs rats fed NF diets: Experiment 1, 0.75 ± 0.06 vs 0.97 ± 0.02 (p < 0.01); Experiment 2, 0.69 ± 0.07 vs 1.12 ± 0.08 (p < 0.01); Experiment 3, 0.57 ± 0.19 vs 1.16 ± 0.15 (p < 0.05). Uremic rats fed HF diet showed more severe vascular calcification (VC) than rats fed NF diet (aortic Ca = 6.3 ± 1.4 vs 1.4 ± 0.1 mg/g tissue, p < 0.001). In conclusion, energy-rich diets increased plasma levels of FGF23, a known risk factor of cardiovascular morbidity and mortality. Even though FGF23 has major phosphaturic actions, feeding HF diets resulted in P retention, likely secondary to decreased renal klotho, and aggravated uremic V

Hot Corinos Chemical Diversity: Myth or Reality?

After almost 20 years of hunting, only about a dozen hot corinos, hot regions enriched in interstellar complex organic molecules (iCOMs), are known. Of them, many are binary systems with the two components showing drastically different molecular spectra. Two obvious questions arise. Why are hot corinos so difficult to find and why do their binary components seem chemically different? The answer to both questions could be a high dust opacity that would hide the molecular lines. To test this hypothesis, we observed methanol lines at centimeter wavelengths, where dust opacity is negligible, using the Very Large Array interferometer. We targeted the NGC 1333 IRAS 4A binary system, for which one of the two components, 4A1, has a spectrum deprived of iCOMs lines when observed at millimeter wavelengths, while the other component, 4A2, is very rich in iCOMs. We found that centimeter methanol lines are similarly bright toward 4A1 and 4A2. Their non-LTE analysis indicates gas density and temperature ($\geq2\times10^6$ cm$^{-3}$ and 100--190 K), methanol column density ($\sim10^{19}$ cm$^{-2}$) and extent ($\sim$35 au in radius) similar in 4A1 and 4A2, proving that both are hot corinos. Furthermore, the comparison with previous methanol line millimeter observations allows us to estimate the optical depth of the dust in front of 4A1 and 4A2, respectively. The obtained values explain the absence of iCOMs line emission toward 4A1 at millimeter wavelengths and indicate that the abundances toward 4A2 are underestimated by $\sim$30\%. Therefore, centimeter observations are crucial for the correct study of hot corinos, their census, and their molecular abundances.Comment: 9 pages, 3 figures, 2 Tables - Published in ApJ Letter