187 research outputs found
High Strain Rate Superplasticity of WE54 Mg Alloy after Severe Friction Stir Processing
Friction stir processing (FSP) was used on coarse-grained WE54 magnesium alloy plates of as-received material. These were subjected to FSP under two different cooling conditions, refrigerated and non-refrigerated, and different severe processing conditions characterized by low rotation rate and high traverse speed. After FSP, ultrafine equiaxed grains and refinement of the coarse precipitates were observed. The processed materials exhibited high resistance at room temperature and excellent superplasticity at the high strain rate of 10−2 s−1 and temperatures between 300 and 400 °C. Maximum tensile superplastic elongation of 726% was achieved at 400 °C. Beyond 400 °C, a noticeable loss of superplastic response occurred due to a loss of thermal stability of the grain size. Grain boundary sliding is the operative deformation mechanism that can explain the high-temperature flow behavior of the ultrafine grained FSP-WE54 alloy, showing increasing superplasticity with increasing processing severity.Project MAT2015-68919-R MINECO/FEDER, Spain, and FPI fellowship number BES2013-063963 (MINECO/FEDER/ESF).Peer reviewe
Eating Disorders as New Forms of Addiction
Eating disorders (ED) seem to share many characteristics with substance-related disorders (SRD). As very often the two conditions run together, it has been proposed that eating dysfunctions could be understood as behavioral forms of addiction. This has lead to the concept of “food addiction,” a proposed new form of addiction. This chapter reviews recent research focusing on the relationship between ED and SRD. Three specific areas are addressed: (a) animal models that suggest the association between substance dependence and compulsive overeating; (b) epidemiological studies that confirm the comorbidity between ED and SRD; and (c) neuroimaging studies that reveal the existence of modifications in the reward circuits following binge eating and other eating dysfunctions. The data from the different studies can be integrated into a model based on the consideration of “food addiction” as a specific form of behavioral addiction that could be applied at least to a group of patients suffering from eating disorders
Dynamic regulation of cell volume and extracellular ATP of human erythrocytes
Introduction: The peptide mastoparan 7 (MST7) triggered in human erythrocytes (rbcs) the release of ATP and swelling. Since swelling is a well-known inducer of ATP release, and extracellular (ATPe), interacting with P (purinergic) receptors, can affect cell volume (Vr), we explored the dynamic regulation between Vr and ATPe. Methods and Treatments: We made a quantitative assessment of MST7-dependent kinetics of Vr and of [ATPe], both in the absence and presence of blockers of ATP efflux, swelling and P receptors. Results: In rbcs 10 μM MST7 promoted acute, strongly correlated changes in [ATPe] and Vr. Whereas MST7 induced increases of 10% in Vr and 190 nM in [ATPe], blocking swelling in a hyperosmotic medium + MST7 reduced [ATPe] by 40%. Pre-incubation of rbcs with 10 μM of either carbenoxolone or probenecid, two inhibitors of the ATP conduit pannexin 1, reduced [ATPe] by 40-50% and swelling by 40-60%, while in the presence of 80 U/mL apyrase, an ATPe scavenger, cell swelling was prevented. While exposure to 10 μM NF110, a blocker of ATP-P2X receptors mediating sodium influx, reduced [ATPe] by 48%, and swelling by 80%, incubation of cells in sodium free medium reduced swelling by 92%. Analysis and Discussion: Results were analyzed by means of a mathematical model where ATPe kinetics and Vr kinetics were mutually regulated. Model dependent fit to experimental data showed that, upon MST7 exposure, ATP efflux required a fast 1960-fold increase of ATP permeability, mediated by two kinetically different conduits, both of which were activated by swelling and inactivated by time. Both experimental and theoretical results suggest that, following MST7 exposure, ATP is released via two conduits, one of which is mediated by pannexin 1. The accumulated ATPe activates P2X receptors, followed by sodium influx, resulting in cell swelling, which in turn further activates ATP release. Thus swelling and P2X receptors constitute essential components of a positive feedback loop underlying ATP-induced ATP release of rbcs.Instituto de Física de Líquidos y Sistemas Biológico
Dynamic regulation of cell volume and extracellular ATP of human erythrocytes
Introduction: The peptide mastoparan 7 (MST7) triggered in human erythrocytes (rbcs) the release of ATP and swelling. Since swelling is a well-known inducer of ATP release, and extracellular (ATPe), interacting with P (purinergic) receptors, can affect cell volume (Vr), we explored the dynamic regulation between Vr and ATPe. Methods and Treatments: We made a quantitative assessment of MST7-dependent kinetics of Vr and of [ATPe], both in the absence and presence of blockers of ATP efflux, swelling and P receptors. Results: In rbcs 10 μM MST7 promoted acute, strongly correlated changes in [ATPe] and Vr. Whereas MST7 induced increases of 10% in Vr and 190 nM in [ATPe], blocking swelling in a hyperosmotic medium + MST7 reduced [ATPe] by 40%. Pre-incubation of rbcs with 10 μM of either carbenoxolone or probenecid, two inhibitors of the ATP conduit pannexin 1, reduced [ATPe] by 40-50% and swelling by 40-60%, while in the presence of 80 U/mL apyrase, an ATPe scavenger, cell swelling was prevented. While exposure to 10 μM NF110, a blocker of ATP-P2X receptors mediating sodium influx, reduced [ATPe] by 48%, and swelling by 80%, incubation of cells in sodium free medium reduced swelling by 92%. Analysis and Discussion: Results were analyzed by means of a mathematical model where ATPe kinetics and Vr kinetics were mutually regulated. Model dependent fit to experimental data showed that, upon MST7 exposure, ATP efflux required a fast 1960-fold increase of ATP permeability, mediated by two kinetically different conduits, both of which were activated by swelling and inactivated by time. Both experimental and theoretical results suggest that, following MST7 exposure, ATP is released via two conduits, one of which is mediated by pannexin 1. The accumulated ATPe activates P2X receptors, followed by sodium influx, resulting in cell swelling, which in turn further activates ATP release. Thus swelling and P2X receptors constitute essential components of a positive feedback loop underlying ATP-induced ATP release of rbcs.Instituto de Física de Líquidos y Sistemas Biológico
Venous thromboembolism in heart transplant recipients: Incidence, recurrence and predisposing factors
[Abstract] Background. A high frequency of venous thromboembolism (VTE) has been observed after lung, kidney, and liver transplantation. However, data about the incidence of this complication among heart transplant (HT) recipients are lacking.
Methods. We analyzed the incidence, recurrence, and predisposing factors of VTE in a single-center cohort of 635 patients who underwent HT from April 1991 to April 2013. Deep venous thrombosis (DVT) and pulmonary embolism (PE) were considered as VTE episodes.
Results. During a median post-transplant follow-up of 8.4 years, 62 VTE episodes occurred in 54 patients (8.5%). Incidence rates of VTE, DVT, and PE were, respectively, 12.7 (95% confidence interval [CI], 9.7–16.3), 8.4 (95% CI, 6.0–11.4), and 7.0 (95% CI 4.8–9.7) episodes per 1,000 patient-years. Incidence rates of VTE during the first post-transplant year and beyond were, respectively, 45.1 (95% CI, 28.9–67.1) and 8.7 (95% CI 6.2–11.2) episodes per 1,000 patient-years. The incidence rate of VTE recurrence after a first VTE episode was 30.5 (95% CI, 13.2–60.2) episodes per 1,000 patient-years. By means of multivariable Cox regression, chronic renal dysfunction, older age, obesity, and the use of mammalian target of rapamycin inhibitors were identified as independent risk factors for VTE among HT recipients.
Conclusions. VTE is a frequent complication after HT, mainly during the first post-operative year. In view of a high recurrence rate, long-term anti-coagulation should be considered in HT recipients who experience a first VTE episode
Biodiversity of Gastropod in the Southeastern Gulf of California, Mexico
Currently, studying the environment is important because of the phenomena that take place on the earth every day. That is why it is a priority to carry out studies that relate environmental changes to the biology of organisms. This allows us to know the interactions with the environment, and in this way solve, reduce or prevent ecological and economic problems, if they are organisms with a commercial value. The objective of this investigation is to determine ecological parameters of the gastropod community from the intertidal zone on five islands from the Gulf of California, México, to model the diversity, distribution and abundance of malacological fauna. We considered to evaluate the Shannon-Wiener diversity (H′), Pielou’s of evenness (J) and the Margalef species richness indexes, in order to evaluate through an analysis from biotic and abiotic factors, the species status that was collected from the exposed and non-exposed zone tidal. The generated data were contemplated from a year-based biodiversity project (2016–2017) on the following islands: Patos, Bledos, Bleditos, Tunosa, and Mazocahui which belong to the Ohuira lagoon in Ahome, Sinaloa, southeast of the Gulf of California, México. Likewise a status about the importance of gastropods is mentioned for the study area
Protease inhibitor monotherapy is associated with a higher level of monocyte activation, bacterial translocation and inflammation
Introduction Monotherapy with protease-inhibitors (MPI) may be an alternative to cART for HIV treatment. We assessed the impact of this strategy on immune activation, bacterial translocation and inflammation. Methods We performed a cross-sectional study comparing patients on successful MPI (n=40) with patients on cART (n=20). Activation, senescence, exhaustion and differentiation stage in CD4+ and CD8+ T lymphocyte subsets, markers of monocyte activation, microbial translocation, inflammation, coagulation and low-level viremia were assessed. Results CD4+ or CD8+ T lymphocyte subset parameters were not significantly different between both groups. Conversely, as compared with triple cART, MPI patients showed a higher proportion of activated monocytes (CD14+ CD16−CD163+ cells, p=0.031), soluble markers of monocyte activation (sCD14 p=0.004, sCD163 p=0.002), microbial translocation (lipopolysaccharide (LPS)-binding protein; LBP p=0.07), inflammation (IL-6 p=0.04) and low-level viremia (p=0.035). In a multivariate model, a higher level of CD14+ CD16−CD163+ cells and sCD14, and presence of very low-level viremia were independently associated with MPI. Monocyte activation was independently associated with markers of inflammation (IL-6, p=0.006), microbial translocation (LBP, p=0.01) and low-level viremia (p=0.01). Conclusions Patients on MPI showed a higher level of monocyte activation than patients on standard therapy. Microbial translocation and low-level viremia were associated with the high level of monocyte activation observed in patients on MPI. The long-term clinical consequences of these findings should be assessed
High-accuracy determination of the U 238 / U 235 fission cross section ratio up to ≈1 GeV at n-TOF at CERN
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOIThe U238 to U235 fission cross section ratio has been determined at n-TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at n-TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n-TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.Peer reviewedFinal Published versio
Comparación de la actividad in vitro de la tigeciclina mediante la prueba de difusión con disco, el método demicrodilución manual y el sistema automatizado Vitek 2
La tigeciclina es un antibiótico de amplio espectro conactividad frente a bacterias multirresistentes. Existen dificultades en la determinación de la actividad in vitro a travésde las técnicas microbiológicas convencionales. El objetivo del estudio fue evaluar tres marcas diferentes de medioagar Mueller-Hinton para utilizar en el método de difusión con disco y el método automatizado Vitek 2, y compararloscon la prueba tradicional de microdilución manual (Paneles Trek) frente a 200 aislamientos de microorganismos gramnegativos (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens y Acinetobacterbaumannii). Para el grupo de las enterobacterias, el medio con mejor desempeño fue el producido por Becton Dickinson,que tuvo 32,5% de errores menores y 3,8% de errores mayores. No se presentaron errores mayores con ningúnmedio. Se encontró una alta concordancia (94%) entre el método de microdilución manual y el Vitek 2. Para A.baumannii, el medio con mejor desempeño fue el Mueller-Hinton elaborado por Becton Dickinson, con 12,5% deerrores menores y 2,5% de errores mayores. Los resultados sugieren que el método Vitek 2 es una herramienta válidaen la determinación de la sensibilidad a la tigeciclina y que existen diferencias muy grandes en la prueba de difusióncon disco según la marca comercial de medio utilizado.Q4Q3Artículo breve208-211Tigecycline is a broad spectrum antibiotic having activity against multiresistant isolates. In vitro susceptibility testing is difficult to perform with the use of traditional microbiological techniques. The aim of this study was to evaluate the disk diffusion test with three different Mueller-Hinton agar brands, and the Vitek 2 automated system in comparison with the standard broth microdilution method against 200 gram-negative isolates (Escherichia coil, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens and Acinetobacter baumannii). Among Enterobacteriaceae, the Becton Dickinson agar had the lowest rate of minor (32.5%) and major errors (3.8%). No very major errors were found. For A. baumanni, the rate of minor and major errors was lower. A high rate of agreement (94%) was found between the broth microdilution method and the Vitek 2 system. Our results show that there are important differences between agars used for the disk diffusion test, and that Vitek 2 is a valid tool for susceptibility testing in clinical laboratories
Nesfatin-1 in human and murine cardiomyocytes: synthesis, secretion, and mobilization of GLUT-4
Nesfatin-1, a satiety-inducing peptide identified in hypothalamic regions that regulate energy balance, is an integral regulator of energy homeostasis and a putative glucose-dependent insulin coadjuvant. We investigated its production by human cardiomyocytes and its effects on glucose uptake, in the main cardiac glucose transporter GLUT-4 and in intracellular signaling. Quantitative RT-PCR, Western blots, confocal immunofluorescence microscopy, and ELISA of human and murine cardiomyocytes and/or cardiac tissue showed that cardiomyocytes can synthesize and secrete nesfatin-1. Confocal microscopy of cultured cardiomyocytes after GLUT-4 labeling showed that nesfatin-1 mobilizes this glucose transporter to cell peripherals. The rate of 2-deoxy-D-[(3)H]glucose incorporation demonstrated that nesfatin-1 induces glucose uptake by HL-1 cells and cultured cardiomyocytes. Nesfatin-1 induced dose- and time-dependent increases in the phosphorylation of ERK1/2, AKT, and AS160. In murine and human cardiac tissue, nesfatin-1 levels varied with diet and coronary health. In conclusion, human and murine cardiomyocytes can synthesize and secrete nesfatin-1, which is able to induce glucose uptake and the mobilization of the glucose transporter GLUT-4 in these cells. Nesfatin-1 cardiac levels are regulated by diet and coronary health
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