Elastic modulus and hydraulic permeability of MDCK monolayers.

The critical role of cell mechanics in tissue health has led to the development of many in vitro methods that measure the elasticity of the cytoskeleton and whole cells, yet the connection between these local cell properties and bulk measurements of tissue mechanics remains unclear. To help bridge this gap, we have developed a monolayer indentation technique for measuring multi-cellular mechanics in vitro. Here, we measure the elasticity of cell monolayers and uncover the role of fluid permeability in these multi-cellular systems, finding that the resistance of fluid transport through cells controls their force-response at long times.

Lymphogranuloma venereum in Barcelona, 2007-2012: the role of seroadaptation in men who have sex with men.

This study describes the incidence rate of reported lymphogranuloma venereum (LGV) in men who have sex with men (MSM) in Barcelona from 2007 to 2012. Epidemiological, clinical and sexual behaviour characteristics of LGV cases are described. Seroadaptive behaviours as a transmission risk factor were assessed by a telephone questionnaire during 2012. Data were handled on a strictly confidential basis. LGV annual rate ratios in MSM were compared with cases from 2007. Differences were statistically analysed with a Poisson test. The incidence rate of LGV in MSM aged 15-69 years ranged from 32·1/105 MSM per year in 2007 to 182·7/105 MSM per year in 2012. In 2012, 31/51 LGV cases (61%) answered the telephone questionnaire, of which 84% (26/31) were HIV positive, 39% (12/31) reported having sex according to their partners' serostatus and 7% (2/31) used strategic positioning. The incidence of LGV has increased since 2007 and mainly affects HIV-positive MSM. It is probable that seroadaptation has facilitated LGV transmission.

Polymer fluctuation lubrication in hydrogel gemini interfaces.

Interfacial sliding speed and contact pressure between the sub-units of particulate soft matter assemblies can vary dramatically across systems and with dynamic conditions. By extension, frictional interactions between particles may play a key role in their assembly, global configuration, collective motion, and bulk material properties. For example, in tightly packed assemblies of microgels - colloidal microspheres made of hydrogel - particle stiffness controls the fragility of the glassy state formed by the particles. The interplay between particle stiffness and shear stress is likely mediated by particle-particle normal forces, highlighting the potential role of hydrogel-hydrogel friction. Here we study friction at a twinned "Gemini" interface between hydrogels. We construct a lubrication curve that spans four orders of magnitude in sliding speed, and find qualitatively different behaviour from traditional lubrication of engineering material surfaces; fundamentally different types of lubrication occur at the hydrogel Gemini interface. We also explore the role played by polymer solubility and hydrogel-hydrogel adhesion in hydrogel friction. We find that polymer network elasticity, mesh size, and single-chain relaxation times can describe friction at the gel-gel interface, including a transition between lubrication regimes with varying sliding speed.

New times for migrants' health in Europe.

Patterns of migration can change greatly over time, with the size and composition of migrant populations reflecting both, current and historical patterns of migration flows. The recent economic crisis has caused a decrease on migration flows towards the most affected areas, as well as cut offs in health interventions addressed to migrants. The objective of this paper is to review available data about interventions on migrants' health in Europe, and to describe changes in migrant health policies across Europe after the economic crisis, that can have a negative effect in their health status. Although migrants have the right to health care under legal settlements issued by the EU, there is no a standard European approach to offer health care to migrants, since; policies in each EU Member State are developed according to specific migrant experience, political climate, and attitudes towards migration. Migrants use to face greater health problems and major health care access barriers, compared with their counterparts from the EU. Therefore, migrant health policies should focus in protects this vulnerable group, especially during economic hardship, taking into account economic and socio-demographic risk factors. There is an especial need for research in the cost-effectiveness of investing in the health care of the migrant population, demonstrating the benefit of such, even in the health of the European native population, and the need for constant intervention despite of resource constraints.

Cell friction.

Cells sense and respond to their environment. Mechanotransduction is the process by which mechanical forces, stress, and strains are converted into biochemical signals that control cell behavior. In recent decades it has been shown that appropriate mechanical signals are essential to tissue health, but the role of friction and direct contact shearing across cell surfaces has been essentially unexplored. This, despite the obvious existence of numerous biological tissues whose express function depends on sliding contacts. In our studies on frictional interactions of corneal cells we find that the friction coefficients are on the order of mu = 0.03-0.06 for in vitro and in vivo experiments. Additionally, we observe cell death after single cycles of sliding at contact pressures estimated to be approximately 12 kPa. These experimental results suggest that frictional contact forces produce mechanical stresses and strains that are in the cellular mechanosensing ranges.