Broadband dielectric spectroscopy of nanocomposites based on PVDF and expanded graphite

International audienceNanocomposites based on poly (vinylidene fluoride) (PVDF) and expanded graphite (EG) were prepared by non-solvent precipitation from solution with different EG concentrations. Films were obtained by compression molding and their structural and dielectric properties studied. From Wide Angle X-ray Scattering (WAXS) experiments, it can be assessed that for all EG concentrations the -crystalline phase of PVDF is the predominant crystalline form. However, for composites with high nanoadditive content, higher than 3 wt.%, the -crystalline phase is also detected. Dielectric spectroscopy results showed that the nanocomposites present both high dielectric constant and electrical conductivity at low percolation threshold

Quantifying the micellar structure formed from hydrocarbon-fluorocarbon surfactants

Many technological formulations contain mixtures of surfactants, each contributing some distinct property. Characteristics of each surfactant are often modulated in the mixture, based on the interactions between the various components present. Here, the mixing of the hydrocarbon surfactant cetyltrimethyl ammonium bromide (C16TAB) and the fluorocarbon surfactant, Zonyl-FSN-100 with average chemical structure of C8F17C2H4 (OC2H4)9OH, is quantified, in particular, the size and shape of the micelles and their critical micelle concentration (CMC). The CMC data suggest there are specific interactions between the two components which are strongly antagonistic. Small-angle neutron scattering (SANS) has been used to quantify the size and shape of the micelle, and these data indicate that the single component FSN-100 forms disc-like micelles with a small aggregation number (~65) and the C16TAB forms globular, charged micelles with a larger aggregation number (135). The aggregation number of the mixed micelle is substantially greater than either of the pure species. Overall, a detailed study of CTAB, FSN-100 and their mixture systems will be presented in this paper

How does gender influence the recognition of cardiovascular risk and adherence to self-care recommendations? : a study in polish primary care

Background: Studies have shown a correlation between gender and an ability to change lifestyle to reduce the risk of disease. However, the results of these studies are ambiguous, especially where a healthy lifestyle is concerned. Additionally, health behaviors are strongly modified by culture and the environment. Psychological factors also substantially affect engagement with disease-related lifestyle interventions. This study aimed to examine whether there are differences between men and women in the frequency of health care behavior for the purpose of reducing cardiovascular risk (CVR), as well as cognitive appraisal of this type of risk. We also aimed to identify the psychological predictors of engaging in recommended behavior for reducing the risk of cardiovascular disease after providing information about this risk in men and women. Methods: A total of 134 consecutive eligible patients in a family practice entered a longitudinal study. At initial consultation, the individual’s CVR and associated health burden was examined, and preventive measures were recommended by the physician. Self-care behavior, cognitive appraisal of risk, and coping styles were then assessed using psychological questionnaires. Six months after the initial data collection, the frequency of subjects’ self-care behavior was examined. Results: We found an increase in health care behavior after providing information regarding the rate of CVR in both sexes; this increase was greater for women than for men. Women followed self-care guidelines more often than men, particularly for preventive measures and dietary advice. Women were more inclined to recognize their CVR as a challenge. Coping style, cognitive appraisal, age, level of health behaviors at baseline and CVR values accounted for 48% of the variance in adherence to self-care guidelines in women and it was 52% in men. In women, total risk of CVD values were most important, while in men, cognitive appraisal of harm/loss was most important. Conclusions: Different predictors of acquisition of health behavior are encountered in men and women. Our results suggest that gender-adjusted motivation models influencing the recognition process need to be considered to optimize compliance in patients with CVR

Treatment of Older Patients With Mantle Cell Lymphoma (MCL):Long-Term Follow-Up of the Randomized European MCL Elderly Trial

PURPOSE: In an update of the randomized, open-label, phase III European Mantle Cell Lymphoma (MCL) Elderly trial (ClinicalTrials.gov identifier: NCT00209209), published in 2012, we aimed to confirm results on long-term outcome focusing on efficacy and safety of long-term use of rituximab maintenance. PATIENTS AND METHODS: Five hundred sixty patients with newly diagnosed MCL underwent a first random assignment between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and rituximab, fludarabine, and cyclophosphamide (R-FC) induction, followed by a second random assignment in 316 responders between rituximab and interferon alfa maintenance, to be continued until progression. We compared progression-free survival from the second randomization and overall survival (OS) from the first or second randomizations. RESULTS: After a median follow-up time of 7.6 years, the previously described difference in OS between the induction arms persisted (median, 6.4 years after R-CHOP [n = 280] v 3.9 years after R-FC [n = 280]; P = .0054). Patients responding to R-CHOP had median progression-free survival and OS times of 5.4 and 9.8 years, respectively, when randomly assigned to rituximab (n = 87), compared with 1.9 years (P < .001) and 7.1 years (P = .0026), respectively, when randomly assigned to interferon alfa (n = 97). In 58% and 32% of patients treated with R-CHOP, rituximab maintenance was still ongoing 2 and 5 years from start of maintenance, respectively. After R-FC, rituximab maintenance was associated with an unexpectedly high cumulative incidence of death in remission (22% at 5 years). Toxicity of rituximab maintenance was low after R-CHOP (grade 3-4 leukopenia or infection < 5%) but more prominent in patients on rituximab maintenance after R-FC, in whom grade 3-4 leukopenia (up to 40%) and infections were frequent (up to 15%). CONCLUSION: The excellent results of R-CHOP followed by rituximab maintenance until progression for older patients with MCL persisted in a mature follow-up. Prolongation of rituximab maintenance beyond 2 years is effective and safe