Towards estimating computer users' mood from interaction behaviour with keyboard and mouse

The purpose of this exploratory research was to study the relationship between the mood of computer users and their use of keyboard and mouse to examine the possibility of creating a generic or individualized mood measure. To examine this, a field study (n = 26) and a controlled study (n = 16) were conducted. In the field study, interaction data and self-reported mood measurements were collected during normal PC use over several days. In the controlled study, participants worked on a programming task while listening to high or low arousing background music. Besides subjective mood measurement, galvanic skin response (GSR) data was also collected. Results found no generic relationship between the interaction data and the mood data. However, the results of the studies found significant average correlations between mood measurement and personalized regression models based on keyboard and mouse interaction data. Together the results suggest that individualized mood prediction is possible from interaction behaviour with keyboard and mouse

Nacre extract restores the mineralization capacity of subchondral osteoarthritis osteoblasts

International audienceOsteoarthritis (OA) is the most common cause of joint chronic pain and involves the entire joints. Subchondral osteoarthritic osteoblasts present a mineralization defect and, to date, only a few molecules (Vitamin D3 and Bone Morphogenetic Protein2) could improve the mineralization potential of this cell type. In this context, we have tested for the first time the effect of nacre extract on the mineralization capacity of osteoblasts from OA patients. Nacre extract is known to contain osteogenic molecules which have demonstrated their activities notably on the MC3T3 pre-osteoblastic cell line. For this goal, molecules were extracted from nacre (ESM, Ethanol Soluble Matrix) and tested on osteoblasts of the subchondral bone from OA patients undergoing total knee replacement and on MC3T3 cells for comparison. We chose to investigate the mineralization with Alizarin Red staining and with the study of extracellular matrix (ECM) structure and composition. In a complementary way the structure of the ECM secreted during the mineralization phase was investigated using second harmonic generation (SHG). Nacre extract was able to induce the early presence (after 7 days) of precipitated calcium in cells. Raman spectroscopy and electron microscopy showed the presence of nanograins of an early crystalline form of calcium phosphate in OA osteoblasts ECM and hydroxyapatite in MC3T3 ECM. SHG collagen fibers signal was present in both cell types but lower for OA osteoblasts. In conclusion, nacre extract was able to rapidly restore the mineralization capacity of osteoarthritis osteoblasts, therefore confirming the potential of nacre as a source of osteogenic compounds. (C) 2015 Elsevier Inc. All rights reserved

pH-controlled recovery of placenta-derived mesenchymal stem cell sheets

Widely used in different biomedical applications, polyelectrolyte multilayers provide inter alia an attractive way for manufacturing of bio-functionalized, stimuli responsive surface coatings to control cellular behavior. In this study a novel polyelectrolyte-based platform for the engineering and controllable detachment of human mesenchymal stem cell (MSC) sheets is presented. Thin films obtained by layer-by-layer deposition of cationic poly(allylamine hydrochloride) (PAH) and anionic poly(styrene sulfonate) (PSS) polyelectrolytes on conductive indium tin oxide (ITO) electrodes allowed for the fast formation of viable sheets from human placenta-derived mesenchymal stem cells (PD-MSCs). Resulting stem cell sheets retained their phenotypical profile and mesodermal differentiation potency. Both electrochemically-induced local pH lowering and global decrease of the environmental pH allowed for a rapid detachment of intact stem cell sheets. The recovered stem cell sheets remained viable and maintained their capacity to differentiate toward the adipogenic and osteogenic lineages. This novel polyelectrolyte multilayer based platform represents a promising, novel approach for the engineering of human stem cell sheets desired for future clinical applications

Effect of Molecular Composition of Heparin and Cellulose Sulfate on Multilayer Formation and Cell Response

Here, the layer-by-layer method was applied to assemble films from chitosan paired with either heparin or a semisynthetic cellulose sulfate (CS) that possessed a higher sulfation degree than heparin. Ion pairing was exploited during multilayer formation at pH 4, while hydrogen bonding is likely to occur at pH 9. Effects of polyanions and pH value during layer formation on multilayers properties were studied by surface plasmon resonance ("dry layer mass"), quartz crystal microbalance with dissipation monitoring ("wet layer mass"), water contact angle, and zeta potential measurements. Bioactivity of multilayers was studied regarding fibronectin adsorption and adhesion/proliferation of C2C12 myoblast cells. Layer growth and dry mass were higher for both polyanions at pH 4 when ion pairing occurred, while it decreased significantly with heparin at pH 9. By contrast, CS as polyanion resulted also in high layer growth and mass at pH 9, indicating a much stronger effect of hydrogen bonding between chitosan and CS. Water contact angle and zeta potential measurements indicated a more separated structure of multilayers from chitosan and heparin at pH 4, while CS led to a more fuzzy intermingled structure at both pH values. Cell behavior was highly dependent on pH during multilayer formation with heparin as polyanion and was closely related to fibronectin adsorption. By contrast, CS and chitosan did not show such dependency on pH value, where adhesion and growth of cells was high. Results of this study show that CS is an attractive candidate for multilayer formation that does not depend so strongly on pH during multilayer formation. In addition, such multilayer system also represents a good substrate for cell interactions despite the rather soft structure. As previous studies have shown specific interaction of CS with growth factors, multilayers from chitosan and CS may be of great interest for different biomedical applications

Individual and healthcare supply-related barriers to treatment initiation in HIV-positive patients enrolled in the Cameroonian antiretroviral treatment access programme

International audienceIncreasing demand for antiretroviral treatment (ART) together with a reduction in international funding during the last decade may jeopardize access to ART. Using data from a cross-sectional survey conducted in 2014 in 19 HIV services in the Centre and Littoral regions in Cameroon, we investigated the role of healthcare supply-related factors in time to ART initiation in HIV-positive patients eligible for ART at HIV diagnosis. HIV service profiles were built using cluster analysis. Factors associated with time to ART initiation were identified using a multilevel Cox model. The study population included 847 HIV-positive patients (women 72%, median age: 39 years). Median (interquartile range) time to ART initiation was 1.6 (0.5-4.3) months. Four HIV service profiles were identified: (1) small services with a limited staff practising partial task-shifting (n = 4); (2) experienced and well-equipped services practising task-shifting and involving HIV community-based organizations (n = 5); (3) small services with limited resources and activities (n = 6); (4) small services providing a large range of activities using task-shifting and involving HIV community-based organizations (n = 4). The multivariable model showed that HIV-positive patients over 39 years old [hazard ratio: 1.26 (95% confidence interval) (1.09-1.45), P = 0.002], those with disease symptoms [1.21 (1.04-1.41), P = 0.015] and those with hepatitis B co-infection [2.31 (1.15-4.66), P = 0.019] were all more likely to initiate ART early. However, patients in the first profile were less likely to initiate ART early [0.80 (0.65-0.99), P = 0.049] than those in the second profile, as were patients in the third profile [association only significant at the 10% level; 0.86 (0.72-1.02), P = 0.090]. Our findings provide a better understanding of the role played by healthcare supply-related factors in ART initiation. In HIV services with limited capacity, task-shifting and support from community-based organizations may improve treatment access. Additional funding is required to relieve healthcare supply-related barriers and achieve the goal of universal ART access