Comparative analysis of neutronics/thermal-hydraulics multi-scale coupling for LWR analysis

The aim of the research described in this paper is to perform consistent comparative analyses of two different approaches for coupling of two-scale, two-physics phenomena in reactor core calculations. The physical phenomena of interest are the neutronics and the thermal-hydraulics core behaviors and their interactions, while the spatial scales are the “global” (assembly/channel-wise) and the “local” (pin/sub-channel-wise). The objective is three-fold: qualification of coupled code systems by consistent step-by-step cross-comparison (in order to understand the prediction deviations in both neutronics and thermal-hydraulics parameters); assessment of fine scale (local/subchannel-wise) thermal-hydraulic effects; and evaluation of the impact of on-line modeling of interactions of the two spatial scales. The reported work is within the cooperation between the Universidad Politécnica de Madrid (UPM), Spain and the Pennsylvania State University (PSU), USA. The paper first presents the two multi-scale coupled code systems followed by cross-comparisons for steady state calculations. Selected results are discussed to highlight some of the issues involved in comparative analysis of coupled multi-scale simulations. The transient comparisons are subject of future work and publications

Control of fissures generated by the retraction in rigid pavements, applying synthetic fibers of recycled polypropylene.

The retraction affects the setting process and the useful life of the concrete with the appearance of fissures; in last year's studies and methods have been generated to mitigate and control it with the use of different products and applications. The development of road infrastructure with the use of concrete as a rolling folder, requires methods to guarantee the durability and reduce the effects of the efforts incorporated by the use, climatic conditions, support base and restrictions of movement of the structure. To evaluate the effects of recycled synthetic polypropylene fibers in plastic retraction tests (ASTM C 1579), 3 mix designs were prepared with different ratios 58 gr., 116 gr., and 176 gr. of recycled and virgin synthetic fibers; the most significant and positive result to reduce fissures without affecting the resistance of concrete by bending and compression, was 0.50 mm without addition fibers, 0.10 mm and 0.15 mm with 176 gr. of virgin and recycled synthetic fibers. Finally, it can be concluded that adding a ratio of 4 kg per m3 allows good workability, in addition, the costs of the fibers are not representative compared to the high costs for future repairs

Anisotropic Dirac cones in monatomic hexagonal lattices

In the last few years, the fascinating properties of graphene have been thoroughly investigated. The existence of Dirac cones is the most important characteristic of the electronic band-structure of graphene. In this theoretical paper, hexagonal monolayers of silicon (h-Si) and germanium (h-Ge) are examined using density functional theory, within the generalized gradient approximation. Our numerical results indicate that both h-Si and h-Ge are chemically stable. The lattice parameters, electronic dispersion relations and densities of states for these systems are reported. The electronic dispersion relations display Dirac cones with the symmetry of an equilateral triangle (the group D$_3$) in the vicinity of the K points. Hence, the Fermi velocity depends on the wave vector direction around $K$ points. Fermi velocities for holes and electrons are significantly different. The maximum and minimum Fermi velocities are also reported.Comment: 7 pages, 9 figures. Accepted for publication in The European Physical Journal B (EPJB

Solidification of small para-H2 clusters at zero temperature

We have determined the ground-state energies of para-H$_2$ clusters at zero temperature using the diffusion Monte Carlo method. The liquid or solid character of each cluster is investigated by restricting the phase through the use of proper importance sampling. Our results show inhomogeneous crystallization of clusters, with alternating behavior between liquid and solid phases up to N=55. From there on, all clusters are solid. The ground-state energies in the range N=13--75 are established and the stable phase of each cluster is determined. In spite of the small differences observed between the energy of liquid and solid clusters, the corresponding density profiles are significantly different, feature that can help to solve ambiguities in the determination of the specific phase of H$_2$ clusters.Comment: 17 pages, accepted for publication in J. Phys. Chem.

Combined deficiency of Notch1 and Notch3 causes pericyte dysfunction, models CADASIL, and results in arteriovenous malformations

Pericytes regulate vessel stability and pericyte dysfunction contributes to retinopathies, stroke, and cancer. Here we define Notch as a key regulator of pericyte function during angiogenesis. In Notch1(+/-); Notch3(-/-) mice, combined deficiency of Notch1 and Notch3 altered pericyte interaction with the endothelium and reduced pericyte coverage of the retinal vasculature. Notch1 and Notch3 were shown to cooperate to promote proper vascular basement membrane formation and contribute to endothelial cell quiescence. Accordingly, loss of pericyte function due to Notch deficiency exacerbates endothelial cell activation caused by Notch1 haploinsufficiency. Mice mutant for Notch1 and Notch3 develop arteriovenous malformations and display hallmarks of the ischemic stroke disease CADASIL. Thus, Notch deficiency compromises pericyte function and contributes to vascular pathologies.Peer reviewe

Intramural esophagic hematoma secondary to coumarinic anticoagulation: a case report

Esophagic Intramural Hematoma is an uncommon clinical condition, with a prognosis which is essentially benign. On most cases, a predisposing or precipitating factor may be seen, with the most common ones being the history of esophagic instrumentation, food impactations and thrombocytopenia. In the following manuscript, the authors present the case of a 54-years-old male with history of valve replacement surgery, who was treated at the Clinica Cardiovascular (Medellin, Colombia), with a clinical case of Intramural Esophagic Hematoma that was later confirmed to be due to a Coumarinic overanticoagulation. On this case, it is evidenced that Intramural Esophagic Hematoma is an unrecognized complication of Courmarinic anticoagulation therapy

A False Start in the Race Against Doping in Sport: Concerns With Cycling’s Biological Passport

Professional cycling has suffered from a number of doping scandals. The sport’s governing bodies have responded by implementing an aggressive new antidoping program known as the biological passport. Cycling’s biological passport marks a departure from traditional antidoping efforts, which have focused on directly detecting prohibited substances in a cyclist’s system. Instead, the biological passport tracks biological variables in a cyclist’s blood and urine over time, monitoring for fluctuations that are thought to indirectly reveal the effects of doping. Although this method of indirect detection is promising, it also raises serious legal and scientific concerns. Since its introduction, the cycling community has debated the reliability of indirect biological-passport evidence and the clarity, consistency, and transparency of its use in proving doping violations. Such uncertainty undermines the legitimacy of finding cyclists guilty of doping based on this indirect evidence alone. Antidoping authorities should address these important concerns before continuing to pursue doping sanctions against cyclists solely on the basis of their biological passports

Cryptic Oral Microbiota: What Is Its Role as Obstructive Sleep Apnea-Related Periodontal Pathogens?

Q2Q2Periodontitis has been commonly linked to periodontopathogens categorized in Socransky’s microbial complexes; however, there is a lack of knowledge regarding “other microorganisms” or “cryptic microorganisms”, which are rarely thought of as significant oral pathogens and have been neither previously categorized nor connected to illnesses in the oral cavity. This study hypothesized that these cryptic microorganisms could contribute to the modulation of oral microbiota present in health or disease (periodontitis and/or obstructive sleep apnea (OSA) patients). For this purpose, the presence and correlation among these cultivable cryptic oral microorganisms were identified, and their possible role in both conditions was determined. Data from oral samples of individuals with or without periodontitis and with or without OSA were obtained from a previous study. Demographic data, clinical oral characteristics, and genera and species of cultivable cryptic oral microorganisms identified by MALDI-TOF were recorded. The data from 75 participants were analyzed to determine the relative frequencies of cultivable cryptic microorganisms’ genera and species, and microbial clusters and correlations tests were performed. According to periodontal condition, dental-biofilminduced gingivitis in reduced periodontium and stage III periodontitis were found to have the highest diversity of cryptic microorganism species. Based on the experimental condition, these findings showed that there are genera related to disease conditions and others related to healthy conditions, with species that could be related to different chronic diseases being highlighted as periodontitis and OSA comorbidities. The cryptic microorganisms within the oral microbiota of patients with periodontitis and OSA are present as potential pathogens, promoting the development of dysbiotic microbiota and the occurrence of chronic diseases, which have been previously proposed to be common risk factors for periodontitis and OSA. Understanding the function of possible pathogens in the oral microbiota will require more research.https://orcid.org/0000-0003-0006-7822https://orcid.org/0000-0002-5841-3014https://orcid.org/0000-0002-8646-8725https://orcid.org/0000-0001-5576-9341https://orcid.org/0000-0002-9884-9242https://orcid.org/0000-0003-1803-9141https://orcid.org/0000-0003-1302-5429Revista Internacional - IndexadaA1N

Patients with obstructive sleep apnea can favor the predisposing factors of periodontitis by the presence of P. melaninogenica and C. albicans, increasing the severity of the periodontal disease

Q2Q2Pacientes con PeriodontitisPacientes con Apnea obstructiva del sueñoObjective: The aim of this study was to analyze the cultivable oral microbiota of patients with obstructive sleep apnea (OSA) and its association with the periodontal condition. Methods: The epidemiology profile of patients and their clinical oral characteristics were determined. The microbiota was collected from saliva, subgingival plaque, and gingival sulcus of 93 patients classified into four groups according to the periodontal and clinical diagnosis: Group 1 (n = 25), healthy patients; Group 2 (n = 17), patients with periodontitis and without OSA; Group 3 (n = 19), patients with OSA and without periodontitis; and Group 4 (n = 32), patients with periodontitis and OSA. Microbiological samples were cultured, classified, characterized macroscopically and microscopically, and identified by MALDI-TOF-MS. The distribution of complexes and categories of microorganisms and correlations were established for inter- and intra-group of patients and statistically evaluated using the Spearman r test (p-value <0.5) and a multidimensional grouping analysis. Result: There was no evidence between the severity of OSA and periodontitis (p = 0.2813). However, there is a relationship between the stage of periodontitis and OSA (p = 0.0157), with stage III periodontitis being the one with the highest presence in patients with severe OSA (prevalence of 75%; p = 0.0157), with more cases in men. The greatest distribution of the complexes and categories was found in oral samples of patients with periodontitis and OSA (Group 4 P-OSA); even Candida spp. were more prevalent in these patients. Periodontitis and OSA are associated with comorbidities and oral conditions, and the microorganisms of the orange and red complexes participate in this association. The formation of the dysbiotic biofilm was mainly related to the presence of these complexes in association with Candida spp. Conclusion: Periodontopathogenic bacteria of the orange complex, such as Prevotella melaninogenica, and the yeast Candida albicans, altered the cultivable oral microbiota of patients with periodontitis and OSA in terms of diversity, possibly increasing the severity of periodontal disease. The link between yeasts and periodontopathogenic bacteria could help explain why people with severe OSA have such a high risk of stage III periodontitis. Antimicrobial approaches for treating periodontitis in individuals with OSA could be investigated in vitro using polymicrobial biofilms, according to our findings.https://orcid.org/0000-0003-0006-7822https://orcid.org/0000-0003-2528-9632https://orcid.org/0000-0002-1387-1935https://orcid.org/0000-0003-1011-4450https://orcid.org/0000-0002-4069-4719https://orcid.org/0000-0001-5576-9341https://orcid.org/0000-0002-9884-9242https://orcid.org/0000-0003-1803-9141https://orcid.org/0000-0003-1302-5429Revista Internacional - IndexadaA1N

Autophagy fights disease through cellular self-digestion

Autophagy, or cellular self-digestion, is a cellular pathway involved in protein and organelle degradation, with an astonishing number of connections to human disease and physiology. For example, autophagic dysfunction is associated with cancer, neurodegeneration, microbial infection and ageing. Paradoxically, although autophagy is primarily a protective process for the cell, it can also play a role in cell death. Understanding autophagy may ultimately allow scientists and clinicians to harness this process for the purpose of improving human health.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62766/1/nature06639.pd