Magnetorheology of alginate ferrogels

Magnetorheological (MR) effect is a phenomenon typical of suspensions of magnetizable particles in a liquid carrier, characterized by strong changes of their mechanical properties in response to applied magnetic fields. Its origin is on the migration of magnetized particles and their aggregation into chain-like structures. However, for ferrogels, consisting of dispersions of magnetic particles in a polymer matrix, migration of particles is hindered by the elastic forces of the polymer network, preventing from strong MR effect. Interestingly, we demonstrate in this manuscript that strong MR effect in robustly cross-linked polymer ferrogels is still possible. Experimental results showed enhancement of the storage modulus of more than one order of magnitude for alginate ferrogels containing less than about 10 vol.% of iron particles under moderate magnetic fields. The differential feature of these ferrogels is that, instead of individual particles, the disperse phase consisted of large clusters of iron microparticles homogeneously distributed within the polymer networks. These clusters of magnetic particles were formed at the stage of the preparation of the ferrogels and their presence within the polymer networks had two main consequences. First, the volume fraction of clusters was considerably larger than this of individual particles, resulting in a larger effective volume fraction of solids. Second, since the force of magnetic attraction between magnetic bodies is roughly proportional to the cube of the body size, the existence of such clusters favored inter-cluster interaction under a magnetic field and the appearance of strong MR effect. On this basis, we demonstrated by theoretical modeling that the strong MR effect displayed by the alginate ferrogels of the present work can be quantitatively explained by assuming the existence of large, roughly spherical particle aggregates formed at the stage of the preparation of the ferrogels. Our theoretical model provides a reasonable quantitative prediction of the experimental resultsThis study was supported by project FIS2017-85954-R (Ministerio de Economía, Industria y Competitividad, MINECO, and Agencia Estatal de Investigación, AEI, Spain, cofunded by Fondo Europeo de Desarrollo Regional, FEDER, European Union). CGV acknowledges financial support by Ministerio de Ciencia, Innovación y Universidades and University of Granada, Spain, for her FPU17/00491 grant. AZ is grateful to the Program of the Ministry of Education and Science of the Russian Federation, projects 02.A03.21.0006, 3.1438.2017/4.6, and 3.5214.2017/6.7 and the Russian Fund of Basic Researches, project 18-08-0017

Developing win-win solutions for virtual placements in informatics: The VALS case

The placements and internships are one of the main paths to get professional background and some skills for students, especially in areas like informatics and computer sciences. The European-funded VALS project tries to promote the virtual placements and establish a new initiative in virtual placements called Semester of Code. This initiative binds higher education institutions, students, companies, foundations and Open Source projects in order to create virtual placements and solve needs that they have in relation with those placements. This paper introduces some projects about virtual placements that other institutions and companies perform, also the paper describes the needs, opinions and considerations about the virtual placements for each stakeholder involved in the placements, to finally explain the design decisions and actions behind the Semester of Code, and how they are intended to get better virtual placements and successful results

TP53 mutations predict disease control in metastatic colorectal cancer treated with cetuximab-based chemotherapy

Recent studies have suggested that activation of the EGFR pathway leads to malignant transformation only if the p53 protein is inactivated. Therefore, we evaluated the impact of TP53 mutations on cetuximab-based chemotherapy (CT) sensitivity in combination with KRAS mutations that have been associated with cetuximab resistance. KRAS and TP53 status were assessed in tumours from 64 metastatic colorectal cancer patients treated with cetuximab-based CT and correlated to clinical response using the Fisher's exact test. Times to progression (TTPs) according to gene status were calculated using the Kaplan–Meier method and compared with log-rank test. TP53 mutations were found in 41 patients and were significantly associated with controlled disease (CD), as defined as complete response, partial response or stable disease (P=0.037) and higher TTP (20 vs 12 weeks, P=0.004). Remarkably, in the subgroup of 46 patients without KRAS mutation, but not in patients with KRAS mutation, TP53 mutations were also associated with CD (P=0.008) and higher TTP (24 vs 12 weeks, P=0.0007). This study suggests that TP53 mutations are predictive of cetuximab sensitivity, particularly in patients without KRAS mutation, and that TP53 genotyping could have a clinical interest to select patients who should benefit from cetuximab-based CT

A Framework for the Collaborative Evaluation of Service Outsourcing Contracts in Pharmaceutical Logistics

The management of pharmaceutical logistics is mainly outsourced to external service providers as it requires an efficient organization of warehouses and drug flows, and an optimized and long-term process planning in collaboration with several healthcare stakeholders. This work develops a reference tool to evaluate the efficiency of the Pharmaceutical Logistics Service Outsourcing Contract, which includes the technical specifications and the operating procedures of the logistic service. It structures the data to be collected and analysed, from the viewpoint of the several stakeholders of the drug logistics service, for evaluating the elements of: Complexity, Price, Management system, and Quality

Simulation of Patient-Centred Scenarios for the Improvement of Transportation Service in Hospitals

Hospitals and healthcare facilities are increasingly challenged to ensure an efficient use of resources while achieving a high quality in their services that also maximizes the patients’ safety. This is especially important in the case of transportation of patients whose health conditions require the use of appropriate procedures and tools. This work employs a simulation approach to propose solutions for hospitals to improve the organization of the patient transportation service. Resulting solutions are based on the perspective of the service provider and especially driven by patients’ needs. By using the Arena software, we analysed the service model in an Italian hospital and the variations in the human, physical and intangible resources that could improve the service performance, with a focus on the operations adding value in terms of time and collaborative behaviours among patients and operator

En route vers le Petawatt

Single picosecond pulses have been amplified to the terawatt level by a table-top size Nd :glass amplifier by using the technique of chirped pulse amplification (CPA). The divergence of the beam is twice the diffraction limit making the brightness of this source equal to ∼ 2 x 10+ 18 W/(cm. sr), which is the highest brightness ever reported. The technique of chirped pulse amplification alows the efficient energy extraction from extremely compact amplifier systems. Amplification of chirped pulses over nine orders of magnitude, i.e., from nanojoule to the joule level, has been demonstrated. By using a large scale Nd :glass amplifier system, it should be possible to extend the technique of CPA to the amplification of hundred femtosecond pulses to the hundred joule level leading to petawatt power pulses. These power pulses once focused could produce intensity in the range of 10 23 W/cm2, five order of magnitude over the present state of the art.Des impulsions d'une durée de 1 ps ont été amplifiées jusqu'au niveau du terawatt par un système très compact à verre dopé au néodyme basé sur l'utilisation de la technique d'amplification des impulsions à dérive de fréquence. La divergence du faisceau est égale à deux fois la limite de la diffraction, donnant à cette source une brillance de 2 x 10+ 18 W/(cm 2. sr), ce qui constitue la brillance la plus élevée jamais reportée à ce jour. La technique d'amplification d'impulsions à dérive de fréquence rend possible l'extraction de l'énergie de manière efficace dans des systèmes d'amplification extrêmement compacts. L'amplification des impulsions à dérive de fréquence a été démontrée sur neuf ordres de grandeur, du nanojoule jusqu'au niveau du joule. En utilisant une chaîne d'amplification à verre au néodyme de grandes dimensions, il devrait être possible d'étendre cette technique à l'amplification d'impulsions de cent femtosecondes jusqu'au niveau d'une centaine de joules, générant ainsi une puissance instantanée de l'ordre du pétawatt. La focalisation ultérieure de ces impulsions pourrait alors donner naissance à des intensités de l'ordre de 1023 W/cm2, 5 ordres de grandeurs au-dessus des performances actuelles