Complex oscillatory yielding of model hard sphere glasses

The yielding behaviour of hard sphere glasses under large amplitude oscillatory shear has been studied by probing the interplay of Brownian motion and shear-induced diffusion at varying oscillation frequencies. Stress, structure and dynamics are followed by experimental rheology and Browian Dynamics simulations. Brownian motion assisted cage escape dominates at low frequencies while escape through shear-induced collisions at high ones, both related with a yielding peak in\ $G^{\prime \prime}$. At intermediate frequencies a novel, for HS glasses, double peak in $G^{\prime \prime}$ is revealed reflecting both mechanisms. At high frequencies and strain amplitudes a persistent structural anisotropy causes a stress drop within the cycle after strain reversal, while higher stress harmonics are minimized at certain strain amplitudes indicating an apparent harmonic response.Comment: 4 figures placed at the end with following order: Figure 1, figure 3, figure 4 and figure

Yielding of Hard-Sphere Glasses during Start-Up Shear

Concentrated hard-sphere suspensions and glasses are investigated with rheometry, confocal microscopy, and Brownian dynamics simulations during start-up shear, providing a link between microstructure, dynamics, and rheology. The microstructural anisotropy is manifested in the extension axis where the maximum of the pair-distribution function exhibits a minimum at the stress overshoot. The interplay between Brownian relaxation and shear advection as well as the available free volume determine the structural anisotropy and the magnitude of the stress overshoot. Shear-induced cage deformation induces local constriction, reducing in-cage diffusion. Finally, a superdiffusive response at the steady state, with a minimum of the time-dependent effective diffusivity, reflects a continuous cage breakup and reformation

Colloidal gels under shear: Strain rate effects

Attractive colloidal particles are trapped in metastable states such as colloidal gels at high attraction strengths and attractive glasses and high volume fractions. Under shear such states flow via a two step yielding process that relates to bond and cluster or cage breaking. We discuss the way the structural properties and related stress response are affected by the shear rate. At low rates colloidal gels yield during start-up shear essentially in a single step, exhibiting a single stress overshoot due to creation of compact flowing clusters. With increasing shear rate a second stress overshoot, linked with further cluster breaking up to individual particles, is becoming more pronounced. We further present the age dependence of the two step yielding and wall slip effects often taking place during rheological experiments of colloidal gels. The latter is related both with the shear rate dependent gel structure as well as the time evolution of the near wall structure

Residual Stresses in Glasses

The history dependence of the glasses formed from flow-melted steady states by a sudden cessation of the shear rate $\dot\gamma$ is studied in colloidal suspensions, by molecular dynamics simulations, and mode-coupling theory. In an ideal glass, stresses relax only partially, leaving behind a finite persistent residual stress. For intermediate times, relaxation curves scale as a function of $\dot\gamma t$, even though no flow is present. The macroscopic stress evolution is connected to a length scale of residual liquefaction displayed by microscopic mean-squared displacements. The theory describes this history dependence of glasses sharing the same thermodynamic state variables, but differing static properties.Comment: submitted to Physical Revie

Phase III randomized trial comparing moderate-dose cisplatin to combined cisplatin and carboplatin in addition to mitomycin and ifosfamide in patients with stage IV non-small-cell lung cancer

A phase III randomized trial was conducted in patients with metastatic NSCLC, to determine if, in association with mitomycin (6 mg m–2) and ifosfamide (3 g m–2), the combination of moderate dosages of cisplatin (60 mg m–2) and carboplatin (200 mg m–2) – CarboMIP regimen – improved survival in comparison with cisplatin (50 mg m–2) alone – MIP regimen. A total of 305 patients with no prior chemotherapy were randomized, including 297 patients assessable for survival (147 in the MIP arm and 150 in the CarboMIP arm) and 268 patients assessable for response to chemotherapy. All but eight (with malignant pleural effusion) had stage IV disease. There was a 27% (95% CI, 19–34) objective response (OR) rate to MIP (25% of the eligible patients) and a 33% (95% CI, 24–41) OR rate to CarboMIP (29% of the eligible patients). This difference was not statistically significant (P = 0.34). Duration of response was not significantly different between both arms. There was also no difference (P = 0.67) in survival: median survival times were 28 weeks (95% Cl, 24–32) for MIP and 32 weeks (95% Cl, 26–35) for CarboMIP, with respectively 1-year survival rates of 24% and 23% and 2-year survival rates of 5% and 2%. The main toxicities consisted in emesis, alopecia, leucopenia and thrombocytopenia, that were, except alopecia, significantly more severe in the CarboMIP arm. Our trial failed to demonstrate a significant improvement in response or survival when patients with metastatic NSCLC were treated, in addition to ifosfamide and mitomycin, by combination of moderate dosages of cisplatin and carboplatin instead of moderate dosage of cisplatin alone. The results support the use of a moderate dose (50 mg m–2) of cisplatin in combination with ifosfamide and mitomycin for the chemotherapy of this disease. © 2000 Cancer Research Campaig

Development of an ehealth tool for cancer patients: Monitoring psycho-emotional aspects with the family resilience (fare) questionnaire

In the last decade, clinicians have started to shift from an individualistic perspective of the patient towards family-centred models of care, due to the increasing evidence from research and clinical practice of the crucial role of significant others in determining the patient's adjustment to cancer disease and management. eHealth tools can be considered a means to compensate the services gap and support outpatient care flows. Within the works of the European H2020 iManageCancer project, a review of the literature in the field of family resilience was conducted, in order to determine how to monitor the patient and his/her family's resilience through an eHealth platform. An analysis of existing family resilience questionnaires suggested that no measure was appropriate for cancer patients and their families. For this reason, a new family resilience questionnaire (named FaRe) was developed to screen the patient's and caregiver's psycho-emotional resources. Composed of 24 items, it is divided into four subscales: Communication and Cohesion, Perceived Family Coping, Religiousness and Spirituality, and Perceived Social Support. Embedded in the iManageCancer eHealth platform, it allows users and clinicians to monitor the patient's and the caregivers' resilience throughout the cancer trajector