Modelling lubricated revolute joints in multibody mechanical systems

This work deals with the modelling of lubricated revolute joints in multibody mechanical systems. In most machines and mechanisms, the joints are designed to operate with some lubricant fluid. The high pressures generated in the lubricant fluid act to keep the journal and the bearing apart. Moreover, the thin film formed by lubricant reduces friction and wear, provides load capacity and adds damping to dissipate undesirable mechanical vibrations. In the dynamic analysis of journal–bearings, the hydrodynamic forces, which include both squeeze and wedge effects, produced by the lubricant fluid oppose the journal motion. These forces are obtained by integrating the pressure distribution evaluated with the aid of Reynolds’ equation written for the dynamic regime. The hydrodynamic forces are nonlinear functions of journal centre position and velocity relative to the bearing centre. In a simple way, the hydrodynamic forces built up by the lubricant fluid are evaluated from the state of variable of the system and included into the equations of motion of the mechanical system. Results for an elementary slider–crank mechanism, in which a lubricated revolute joint connects the connecting rod and slider, are used to discuss the assumptions and procedures adopted.Fundação para a Ciência e a Tecnologia (FCT

Eccrine porocarcinoma of the head: An important differential diagnosis in the elderly patient

Background: Eccrine porocarcinoma is a rare malignant tumor of the sweat gland, characterized by a broad spectrum of clinicopathologic presentations. Surprisingly, unlike its benign counterpart eccrine poroma, eccrine porocarcinoma is seldom found in areas with a high density of eccrine sweat glands, like the palms or soles. Instead, eccrine porocarcinoma frequently occurs on the lower extremities, trunk and abdomen, but also on the head, resembling various other skin tumors, as illustrated in the patients described herein. Observations: We report 5 cases of eccrine porocarcinoma of the head. All patients were initially diagnosed as having epidermal or melanocytic skin tumors. Only after histopathologic examination were they classified as eccrine porocarcinoma, showing features of epithelial tumors with abortive ductal differentiation. Characteristic clinical, histopathologic and immunohistochemical findings of eccrine porocarcinomas are illustrated. Conclusion: Eccrine porocarcinomas are potentially fatal adnexal malignancies, in which extensive metastatic dissemination may occur. Porocarcinomas are commonly overlooked, or misinterpreted as squamous or basal cell carcinomas as well as other common malignant and even benign skin tumors. Knowledge of the clinical pattern and histologic findings, therefore, is crucial for an early therapeutic intervention, which can reduce the risk of tumor recurrence and serious complications. Copyright (c) 2008 S. Karger AG, Basel

Reduced basis catalogs for gravitational wave templates

We introduce a reduced basis approach as a new paradigm for modeling, representing and searching for gravitational waves. We construct waveform catalogs for non-spinning compact binary coalescences, and we find that for accuracies of 99% and 99.999% the method generates a factor of about $10-10^5$ fewer templates than standard placement methods. The continuum of gravitational waves can be represented by a finite and comparatively compact basis. The method is robust under variations in the noise of detectors, implying that only a single catalog needs to be generated.Comment: Minor changes in some of the phrasing to match the version as published in PR

Superregular matrices and applications to convolutional codes

The main results of this paper are twofold: the first one is a matrix theoretical result. We say that a matrix is superregular if all of its minors that are not trivially zero are nonzero. Given a a×b, a ≥ b, superregular matrix over a field, we show that if all of its rows are nonzero then any linear combination of its columns, with nonzero coefficients, has at least a−b + 1 nonzero entries. Secondly, we make use of this result to construct convolutional codes that attain the maximum possible distance for some fixed parameters of the code, namely, the rate and the Forney indices. These results answer some open questions on distances and constructions of convolutional codes posted in the literature

Control of lysozyme gene expression in differentiating HL-60 cells

We have investigated the control of lysozyme gene expression in HL-60 cells induced to differentiate into macrophage-like cells with phorbol myristate acetate (PMA). Differentiation, as evidenced by cellular adherence, and morphological changes corresponded temporally to an increase in nonspecific esterase activity. The lysozyme concentration in the medium of uninduced HL-60 cells was 10 Μg/10 7 cells. increasing to a maximum of 46 Μg/10 7 cells after 48 h incubation with PMA (16 nm). At 72 h the lysozyme concentration decreased to 16 Μg/10 7 cells. Intracellular lysozyme activity remained constant throughout differentiation. If HL-60 cells were exposed to PMA for 24 h, washed, then maintained in normal medium, they differentiated normally, confirming their irreversible commitment to differentiate. The increase in lysozyme secretion by these cells, however, is markedly blunted suggesting that continued PMA treatment of differentiated cells is required for their secretion of lysozyme. There is no change in the rate of extracellular degradation of lysozyme during differentiation. The level of lysozyme mRNA does not correlate directly with the amount of lysozyme secreted into the medium. Hybridization of uninduced HL-60 cell RNA with a chicken lysozyme cDNA probe demonstrates moderate hybridization. There is a modest (five-fold) increase in lysozyme mRNA between 0 and 36 h of exposure to PMA, corresponding to the burst of lysozyme secretion by these cells. The lysozyme mRNA decreases to a level which is lower than the original baseline by 72 h, when the cells are still secreting substantial amounts of lysozyme. These data suggest that both transcriptional and post-transcriptional controls are operative in the control of lysozyme gene expression during the differentiation of HL-60 cells. They also imply that lysozyme secretion is not a necessary component in the macrophage-monocyte differentiation of these cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71582/1/j.1365-2141.1985.tb07380.x.pd

Fractional Operators, Dirichlet Averages, and Splines

Fractional differential and integral operators, Dirichlet averages, and splines of complex order are three seemingly distinct mathematical subject areas addressing different questions and employing different methodologies. It is the purpose of this paper to show that there are deep and interesting relationships between these three areas. First a brief introduction to fractional differential and integral operators defined on Lizorkin spaces is presented and some of their main properties exhibited. This particular approach has the advantage that several definitions of fractional derivatives and integrals coincide. We then introduce Dirichlet averages and extend their definition to an infinite-dimensional setting that is needed to exhibit the relationships to splines of complex order. Finally, we focus on splines of complex order and, in particular, on cardinal B-splines of complex order. The fundamental connections to fractional derivatives and integrals as well as Dirichlet averages are presented

Oxonium ion scanning mass spectrometry for large-scale plasma glycoproteomics

Protein glycosylation, a complex and heterogeneous post-translational modification that is frequently dysregulated in disease, has been difficult to analyse at scale. Here we report a data-independent acquisition technique for the large-scale mass-spectrometric quantification of glycopeptides in plasma samples. The technique, which we named ‘OxoScan-MS’, identifies oxonium ions as glycopeptide fragments and exploits a sliding-quadrupole dimension to generate comprehensive and untargeted oxonium ion maps of precursor masses assigned to fragment ions from non-enriched plasma samples. By applying OxoScan-MS to quantify 1,002 glycopeptide features in the plasma glycoproteomes from patients with COVID-19 and healthy controls, we found that severe COVID-19 induces differential glycosylation in IgA, haptoglobin, transferrin and other disease-relevant plasma glycoproteins. OxoScan-MS may allow for the quantitative mapping of glycoproteomes at the scale of hundreds to thousands of samples