Radial fretting is defined as the damage caused by the relative motion of a ball under a variable normal load. The conducted experimental tests proved the existence of this damage even in contacting ...bodies with similar materials and elastic properties; however, the reviewed analytical methods do not predict damage under these conditions, and the numerical methods are time-consuming, especially when the investigation requires the analysis of several loading cases or during large number of cycles. The main objective of this work was to develop a fast analytical method to analyse radial fretting wear. For this purpose, a novel formulation for contact displacements under a normal variable load was built and merged to different contact mechanic formulas. For validation purposes, false brinelling in thrust bearings was used as a representative industrial example. The results were compared with a FEM model showing a relative difference under 9% and a massive reduction of the calculation time of more than 30 000 times, moreover experimental tests were carried out, showing a good agreement between the density of friction energy and the obtained fretting damage what endorse the use of this formulation for the analysis of a large number of cycles and loading cases.
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•An analytical new formulation for radial fretting wear simulation.•An experimental and numerical validation of the proposed methodology.•An industrial application to false brinelling in stationary thrust bearings under variable loading conditions.•An alternative fretting method to FEM simulations with a massive time reduction of 30 000 times.
Ambitious worldwide renewable energy targets are pushing for wind energy to become a mainstream power source. Pitch bearings are some of the most vulnerable components of wind turbines. Inside ...bearings, damage in the inner raceways is significant due to the rolling contact fatigue (RCF) caused by balls. It is well known that methodologies for RCF recommended by international standards are not suitable for fatigue cases where fatigue mechanism encompass multiaxiality, as well as the loading being non-proportional, leading to unnecessary design over-costs. The objective of this work is to develop a new accurate methodology to predict the lifetime of the raceway for a pitch bearing under RCF failure mode and analyse the effect of the pitch control strategy. This methodology will help both, the manufacturer of the bearing and the manufacturer of the turbine, to design a concept focused on the overall performance of the machine.
Out-of-plane shear modulus of the honeycomb core of a sandwich panel and the Young’s modulus in the thickness direction were determined by experimental methods, an analytical approach and by the ...finite element method. As regards experimental methods, static and dynamic test were carried out. For static tests, three-point bending was used for obtaining shear properties according to a methodology proposed recently. For obtaining Young’s modulus, compression tests were carried out. The dynamic test method was based on vibration measurements. Shear modulus was determined in the two principal directions of orthotropy of the honeycomb and results obtained by different ways have been compared. The agreement between shear modulus obtained by both experimental methods is good.
Human toxocariasis is one of the neglected helminthiases and it is caused by the zoonotic roundworm species Toxocara canis and Toxocara cati. Diagnosis of human toxocariasis is based on the ...combination of clinical, parasitological, and epidemiological criteria, as well as serology tests that detect anti-Toxocara antibodies. Notwithstanding, due to the absence of pathognomonic symptoms and signs of the disease, serology is the key evidence to support a conclusive diagnosis. TES-ELISA is the most widely used serological test for diagnosis. However, cross-reaction of TES antigens with antibodies produced to other helminth antigens is a major drawback for its application in countries with high parasitic prevalence. T. canis recombinant antigens have been described as an alternative to native TES for diagnosis. Nevertheless, the selection of antigenic proteins is a complex process that requires validation. In this paper, we developed an eGFP carrier-based system to express and purify blocks of recombinant polypeptides of T. canis antigenic proteins. Intense cross-reaction polypeptides were detected by Immunoblot and avoided to finally produce a chimeric prototype protein. Additionally, a control chimeric protein that harbors the complete tested proteins was produced. Purified chimeric antigens were tested in ELISA and Immunoblot assays with 310 sera samples of negative and positive control individuals. Our results showed that chimeric rCHITC0 and rCHITC1 antigens (with sensitivities of 62% 58%, 38% and 16% in IB-rCHITC0, ELISA-rCHITC0, ELISA-rCHITC1 and IB-rCHITC1 respectively for OLMS) can perform better in terms of specificity (being 91%, 89%, 87% and 76% for ELISA-rCHITC1, IB-rCHITC1, ELISA-rCHITC0 and IB-rCHITC0 respectively for OLMS) than T. canis TES-ELISA (with 61% specificity), giving a higher signal with serum samples of infected individuals as well the possibility to discriminate false positive cases with other parasitic infections. Our data suggest that T. canis chimeric proteins, represent candidate antigens for phase II studies.
Toxocara canis; Immunodiagnostic; TES-ELISA; Recombinant antigens; Chimeric antigens; Cross-reactivity.
Summary
Pathogenesis of cryptococcosis in the central nervous system (CNS) is a topic of ongoing research, including the mechanisms by which this fungus invades and infects the brain. Astrocytes, the ...most common CNS cells, play a fundamental role in the local immune response. Astrocytes might participate in cryptococcosis either as a host or by responding to fungal antigens. To determine the infectivity of Cryptococcus neoformans var. grubii and Cryptococcus gattii in a human astrocytoma cell line and the induction of major histocompatibility complex (MHC) molecules. A glioblastoma cell line was infected with C. neoformans var. grubii and C. gattii blastoconidia labelled with FUN‐1 fluorescent stain. The percentage of infection and expression of HLA class I and II molecules were determined by flow cytometry. The interactions between the fungi and cells were observed by fluorescence microscopy. There was no difference between C. neoformans var. grubii and C. gattii in the percentage infection, but C. neoformans var. grubii induced higher expression of HLA class II than C. gattii. More blastoconidia were recovered from C. neoformans‐infected cells than from C. gattii infected cells. Cryptococcus neoformans var. grubii may have different virulence mechanisms that allow its survival in human glia‐derived cells.
Fungal infections are a major cause of morbidity and mortality in the haematological patients. These infections are mainly due to Candida spp. and Aspergillus spp. Mortality by these infections is ...high, but rates have descended in the latest series due to better antifungal agents. Echinocan-dins are, in vitro, very active against Candida and Aspergillus spp. The objective of the study is to analyse the efficacy and safety of micafungin in the antifungal prophylaxis of haema-tological patients on chemotherapy.
A multicentre, observational retrospective study was performed in 7 Haematology Depart-ments in Spain. Patients admitted to these departments with chemotherapy or immunosuppressive treatment, and who had received antifungal prophylaxis with micafungin between 1 January 2009 and 31 December 2014 were included.
There were 5 cases of probable or proven fun-gal infection (4.8%) according to the 2008 EORTC criteria: 2 proven, 3 probable. The types of fungal infection were 3 as-pergillosis and 2 candidiasis. There were no drop-outs from the prophylaxis with micafungin due to toxicity.
Micafungin is an antifungal agent which, used in prophylaxis, has demonstrated good efficacy and an excellent toxicity profile, making it an apparently interesting option in patients requiring antifungal prophylaxis during their hospitalisation episode.
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