1,920 research outputs found

    Impact of temperature and hydrogen on the nanomechanical properties of a highly deformed high entropy alloy

    Get PDF
    Due to their quite attractive properties, high-entropy alloys have emerged to an intensely studied class of alloys within the past years. Besides their high strength and maintained ductility, literature reports modest sensitivity to hydrogen embrittlement for conventional microstructures. Utilizing severe plastic deformation methods, for example high-pressure torsion, it is possible to further tailor the mechanical properties by microstructure refinement to the nanometer regime, which in turn increases the hydrogen storage capability at internal defects and boundaries. Furthermore, the nanocrystalline grain size provides markedly enhanced strength values, while the high fraction of grain boundaries influences the hydrogen diffusion and storage kinetics. Within this study, the micromechanical characteristics of pure Ni and a single phase face-centered cubic CrMnFeCoNi alloy in fine and ultra-fine grained microstructural conditions, fabricated by high pressure torsion, will be investigated in detail. Moreover, electrochemical in-situ nanoindentation will be employed to determine the impact of hydrogen charging on the mechanical performance of this high-entropy alloy class and will be set into context to result found for pure Ni

    Handgrip strength at midlife and familial longevity

    Get PDF
    Low handgrip strength has been linked with premature mortality in diverse samples of middle-aged and elderly subjects. The value of handgrip strength as marker of "exceptional" human longevity has not been previously explored. We postulated that the genetic influence on extreme survival might also be involved in the muscular strength determination pathway. Therefore, the objective of this study was to assess the muscle strength in a sample of middle-aged adults who are genetically enriched for exceptional survival and comparing them to a control group. We included 336 offspring of the nonagenarian from the Leiden Longevity Study who were enriched for heritable exceptional longevity, and 336 of their partners were used as controls. The Leiden Longevity study was a prospective follow up study of long-living siblings pairs together with their offspring and their partners. Handgrip strength was used as a proxy for overall muscle strength. No significant difference in handgrip strength was seen between the offspring of the nonagenarian and their partners after adjustment for potential confounders including body compositions, sum score of comorbidities, medication use, smoking and alcohol history. The main determinants of midlife handgrip strength were age, gender, total body percentage fat and relative appendicular lean mass. Although midlife handgrip strength has previously been shown to be an important prognostic indicator of survival, it is not a marker of exceptional familial longevity in middleaged adults. This finding suggests that genetic component of susceptibility to extreme survival is likely to be separate from that of muscular strength

    High resolution electronic spectroscopy of a non-linear carbon chain radical C6H4+.

    Get PDF
    The electronic spectrum of a member of a so-far-unstudied class of carbon chain radicals was observed:a nonlinear and noncyclic species. The spectrum was observed more or less accidentally around 604 nm when scanning for coincidences with diffuse interstellar band features in a hydrocarbon plasma. The observed spectrum has a clear rotational and K-type structure. Simulation of the spectrum allowed an accurate determination of the molecular constants of the carrier

    Cytomegalovirus seropositivity is associated with glucose regulation in the oldest old. Results from the Leiden 85-plus Study

    Get PDF
    Background: Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old.Results: CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%, p = 0.016), had a higher level of HbA1c (p = 0.014) and higher non-fasting glucose (p = 0.024) in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation (all p > 0.05).Conclusions: In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly

    Surface properties of 1T-TaS2 and contrasting its electron-phonon coupling with TlBiTe2 from helium atom scattering

    Get PDF
    We present a detailed helium atom scattering study of the charge-density wave (CDW) system and transition metal dichalcogenide 1T-TaS2. In terms of energy dissipation, we determine the electron-phonon (e-ph) coupling, a quantity that is at the heart of conventional superconductivity and may even “drive” phase transitions such as CDWs. The e-ph coupling of TaS2 in the commensurate CDW phase (λ = 0.59 ± 0.12) is compared with measurements of the topo-logical insulator TlBiTe2 (λ = 0.09 ± 0.01). Furthermore, by means of elastic He diffraction and resonance/interference effects in He scattering, the thermal expansion of the surface lattice, the surface step height, and the three-dimensional atom-surface interaction potential are determined including the electronic corrugation of 1T-TaS2. The linear thermal expansion coefficient is similar to that of other transition-metal dichalcogenides. The He−TaS2 interaction is best described by a corrugated Morse potential with a relatively large well depth and supports a large number of bound states, comparable to the surface of Bi2Se3, and the surface electronic corrugation of 1T-TaS2 is similar to the ones found for semimetal surfaces

    Author Correction: High-resolution cryo-EM structure of urease from the pathogen Yersinia enterocolitica

    Get PDF
    A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-19845-z

    Serum triiodothyronine levels and inflammatory cytokine production capacity

    Get PDF
    Increasing evidence suggests that pro-inflammatory cytokines are at play in lowering peripheral thyroid hormone levels during critical illness. Conversely, thyroid hormones have been suggested to enhance production of inflammatory cytokines. In view of these considerations, we hypothesized a mutual association between triiodothyronine and pro-inflammatory cytokines. Therefore we evaluated the relation between both circulating and induced inflammatory markers and serum thyroid function parameters in the Leiden 85-plus Study. We found that higher circulating levels of inflammatory markers were associated with lower levels of free serum triiodothyronine. In turn, higher serum free triiodothyronine levels were related to higher production capacity of pro-inflammatory cytokines after stimulation with lipopolysaccharide. By combining in vivo and ex vivo data, we were able to demonstrate for the first time the existence of a potential feedback mechanism between thyroid function and immune production capacity. We conclude that maintenance of normal thyroid function might be important for a preserved immune response in elderly human populations
    corecore