Search results for "slip"
showing 10 items of 471 documents
Obstructive sleep apnoea independently predicts lipid levels: Data from the European Sleep Apnea Database
2018
Background and objective: Obstructive sleep apnoea (OSA) and dyslipidaemia are independent risk factors for cardiovascular disease. This study investigates the association between OSA and plasma lipid concentrations in patients enrolled in the European Sleep Apnea Database (ESADA) cohort. Methods: The cross-sectional analysis included 8592 patients without physician-diagnosed hyperlipidaemia or reported intake of a lipid-lowering drug (age 50.1 ± 12.7 years, 69.1% male, BMI: 30.8 ± 6.6 kg/m2, mean apnoea–hypopnoea index (AHI): 25.7 ± 25.9 events/h). The independent relationship between measures of OSA (AHI, oxygen desaturation index (ODI), mean and lowest oxygen saturation) and lipid profil…
FABP4 plasma levels are increased in familial combined hyperlipidemia
2010
The lipid profile of familial combined hyperlipidemia (FCHL) shares some characteristics with atherogenic dyslipidemia seen in diabetes, metabolic syndrome, and obesity. Adipocyte fatty acid-binding protein 4 (FABP4) appears to be a determinant of atherogenic dyslipidemia. We examined relationships between FABP4 plasma concentrations, dyslipidemia, and metabolic variables in patients with FCHL. We studied 273 unrelated FCHL patients and 118 control subjects. FABP4 was higher in FCHL than controls, with mean levels of 21.8 (10.1) microg/l and 19.2 (9.2) microg/l, respectively (adjusted P= 0.012). In FCHL, FABP4 correlated to body mass index (BMI), waist circumference, insulin levels, and hom…
Waist-to-height ratio and cardiovascular risk factors in elderly individuals at high cardiovascular risk
2012
Introduction: Several anthropometric measurements have been associated with cardiovascular disease, type-2 diabetes mellitus and other cardiovascular risk conditions, such as hypertension or metabolic syndrome. Waist-to-height-ratio has been proposed as a useful tool for assessing abdominal obesity, correcting other measurements for the height of the individual. We compared the ability of several anthropometric measurements to predict the presence of type-2 diabetes, hyperglycemia, hypertension, atherogenic dyslipidemia or metabolic syndrome. Materials and Methods: In our cross-sectional analyses we included 7447 Spanish individuals at high cardiovascular risk, men aged 55-80 years and wome…
Risk of failure in existing RC balcony and strength verification under degradation phenomena
2020
Abstract In the present paper, the safety conditions of reinforced concrete (RC) balconies subject to degradation phenomena caused by carbonation, presence of chlorides or water infiltration were examined. After a brief review of the typical damages of balconies occurring with detachments of plaster and bricks expulsion, some cases of collapses of balconies recently occurred were presented. Therefore, a calculation model was proposed for a hand verification of the flexural and shear strength of existing corroded T beams cast in place of lightened RC orthotropic slabs forming the balcony and for the calculus of deflection including slippage of steel bars. Diffused and pitting corrosion on st…
Slip Flow Over Structured Surfaces with Entrapped Microbubbles
2008
On hydrophobic surfaces, roughness may lead to a transition to a superhydrophobic state, where gas bubbles at the surface can have a strong impact on a detected slip. We present two-phase lattice Boltzmann simulations of a Couette flow over structured surfaces with attached gas bubbles. Even though the bubbles add slippery surfaces to the channel, they can cause negative slip to appear due to the increased roughness. The simulation method used allows the bubbles to deform due to viscous stresses. We find a decrease of the detected slip with increasing shear rate which is in contrast to some recent experimental results implicating that bubble deformation cannot account for these experiments.…
Molecular Scale Study of Domain Boundaries and Frictional Stick-Slip Motion on Lipid Bilayers
1995
A highly 2-dimensional (2D) anisotropic crystal formation of an organic one component lipid bilayer system is presented measured in air by atomic force microscopy. 2D domains with different crystal orientation could be observed. Their molecularly smooth domain boundaries are perceived to be either commensurable or incommensurable lattice joints. Differences in the orientation of the crystal lattice affects dynamic friction on the micrometer scale. High resolution friction images provide stick-slip motions depending on the scan direction in respect to the lattice orientation. It is shown that sliding friction can be determined by an averaged value of the molecular stick-slip motion of the fr…
Amorphous silica between confining walls and under shear: a computer simulation study
2002
Molecular dynamics computer simulations are used to investigate a silica melt confined between walls at equilibrium and in a steady-state Poisseuille flow. The walls consist of point particles forming a rigid face-centered cubic lattice and the interaction of the walls with the melt atoms is modelled such that the wall particles have only a weak bonding to those in the melt, i.e. much weaker than the covalent bonding of a Si-O unit. We observe a pronounced layering of the melt near the walls. This layering, as seen in the total density profile, has a very irregular character which can be attributed to a preferred orientational ordering of SiO4 tetrahedra near the wall. On intermediate lengt…
Evidence of quantum phase slip effect in titanium nanowires
2012
Electron transport properties of titanium nanowires were experimentally studied. Below the effective diameter $\lesssim$ 50 nm all samples demonstrated a pronounced broadening of the $R(T)$ dependencies, which cannot be accounted for thermal flcutuations. An extensive microscopic and elemental analysis indicates the absence of structural or/and geometrical imperfection capable to broaden the the $R(T)$ transition to such an extent. We associate the effect with quantum flucutuations of the order parameter.
Study and evaluation of fretting critical slip conditions by applying the design of experiments method
2006
Tribological systems are complex systems that require a multi-disciplinary (mechanical, material, physico-chemical) approach where numerous influence factors can be involved. To characterize a contact couple, the intrinsic parameters of the materials as well as the parameters related to the contact loading and the surrounding environment need to be taken into account. Fretting analysis, by means of running condition-fretting maps (RCFM), allows the behavior of the contact couple to be taken into account and to predict the boundary between partial slip and gross slip conditions. This article presents the study of a steel/polycarbonate couple during fretting tests. The study was carried out b…