Role of particle clusters on the rheology of magneto-polymer fluids and gels

Even in absence of cross-linking, at large enough concentration, long polymer strands have a strong influence on the rheology of aqueous systems. In this work, we show that solutions of medium molecular weight (120,000 – 190,000 g/mol) alginate polymer retained a liquid-like behaviour even for concentrations as large as 20 % w/v. On the contrary, solutions of alginate polymer of larger (and also polydisperse) molecular weight (up to 600,000 g/mol) presented a gel-like behaviour already at concentrations of 7 % w/v. We dispersed micron-sized iron particles at a concentration of 5 % v/v in these solutions, which resulted either in stable magnetic fluids or gels, depending on the type of alginate polymer employed (medium or large molecular weight, respectively). These magneto-polymer composites presented a shear-thinning behaviour that allowed injection through a syringe and recovery of the original properties afterwards. More interestingly, application of a magnetic field resulted in the formation of particle clusters elongated along the field direction. The presence of these clusters intensely affected the rheology of the systems, allowing a reversible control of their stiffness. We finally developed theoretical modelling for the prediction of the magnetic-sensitive rheological properties of these magneto-polymer colloids.Ministerio de Economía, Industria y Competitividad, MINECO, and Agencia Estatal de Investigación, AEI, Spain, cofounded by Fondo Europeo de Desarrollo Regional, FEDER, European Union, project FIS2017-85954-R. Ministry of Education and Science of the Russian Federation, projects 02.A03.21.0006; 3.1438.2017/4.6; 3.5214.2017/6.7 as well as to the Russian Fund of Basic Researches, project 19-52-1202

Comparison of heuristic approaches to PCI planning for Quantum Computers

Quantum Computing (QC) provides the possibility to develop new approaches to tackle complex problems. Real-world applications, however, cannot yet be managed directly due to the limitation of present and near-future noisy intermediate-scale quantum (NISQ) computers. Decomposition into smaller and manageable subproblems is often needed to take advantage of QC even when using hybrid (classical-quantum) solvers or solvers that already apply decomposition techniques. In this paper, heuristic decomposition algorithms to solve the Physical Cell Identifier (PCI) problem in 4G cellular networks in a way suitable for QC are presented. The PCI problem can be viewed as a map coloring problem with additional constraints and has been represented in a Quadratic Unconstrained Binary Optimization (QUBO) model, a form that, for instance, a quantum annealing machine could crunch. We propose two strategies, with variable decomposition granularity. The first one solves the problem recursively through bisection (max-cut problem), to use only one qubit to represent the status of the objects, avoiding one-hot encoding and thus minimizing the qubit requirement. The second is a multi-step approach, finally solving sets of randomized modified max-k-cut problems of customizable qubit size. We executed the algorithms on real cellular networks of one of the main Italian national telecom operators (TIM). The results show that all proposed QUBO approaches can be effectively applied to very large problems with similar or better performance of the reference classical algorithm, paving the way for the use on NISQ computers

Histological analysis of the wall of a healthy and varicose vein and their correlation with their biomechanical properties

Objetivos: Las varices son una enfermedad muy frecuente en la población, cuya patogenia aun no está clara. Los cambios en la pared de la vena varicosa respecto a la sana determinan su comportamiento biomecánico y la aparición de varices. El presente estudio tiene por objetivo establecer dichas características estructurales en la pared de la vena sana y varicosa, su correlación con los cambios biomecánicos y su contribución a la patogenia de las varices. Métodos: Se llevó a cabo un estudio descriptivo tomando 10 muestras de vena varicosa de pacientes intervenidos de varices mediante crosectomía de la unión safenofemoral, y 4 muestras de vena sana en pacientes sometidos a amputación en los que se descartó enfermedad venosa previa. Las muestras fueron procesadas para su análisis histológico con microscopía óptica con las tinciones de hematoxilina-eosina, orceína y picrosirius. Se determinaron las propiedades biomecánicas en ambos grupos, calculándose el esfuerzo y deformación de ruptura, así como el módulo elástico medio. Resultados: Se han observado cambios histológicos en la pared de la vena varicosa respecto de la sana, con engrosamiento a nivel intimal y en la capa media, aumento de fibras colágenas, disminución de elásticas y alteración de la morfología de las células musculares lisas que pierden su orientación característica. Asimismo se ha encontrado un menor esfuerzo y deformación de ruptura y una mayor rigidez en el grupo de venas varicosas. Dichas alteraciones contribuyen a la deformidad de la pared venosa y la incompetencia valvular, implicados en la aparición de varices. Conclusiones: Las alteraciones histológicas observadas en la pared de la vena varicosa pueden correlacionarse con los cambios en las características biomecánicas y con el proceso patogénico que favorece la aparición de varices.Purpose: Varicose veins are a very common disease, whose pathogeny still remains unclear. Changes in the varicose vein wall in relation to the normal vein, determine its biomechanical behaviour and the appearance of varicose veins. The purpose of this study is to correlate structural and biomechanical properties of healthy and varicose veins, and its contribution to the appearance of varicose veins. Methods: A descriptive study was performed. 10 samples were taken from patients who underwent varicose vein surgery, which consisted in crosectomy of the safeno-femoral junction, and 4 samples of healthy vein from patients who underwent major amputation after dismissing those with signs or symptoms of venous disease. Results: Histological changes have been observed in the varicose vein wall in relation to the healthy vein, consisting in intimal and media thickening, increased amount of collagen fibres, decrease of elastic fibres, and lack of characteristic morphology and orientation in muscular cells. In addition, a lower strain and deformation rupture, and high stiffness has been observed in varicose veins. These changes contribute to varicose vein deformation, valvular incompetence and the appearance of varicose veins. Conclusion: Histological changes in varicose veins correlate with biomechanical properties and pathogenic process leading to varicose veins appearance

Genetic variants associated with gastrointestinal symptoms in Fabry disease.

Gastrointestinal symptoms (GIS) are often among the earliest presenting events in Fabry disease (FD), an X-linked lysosomal disorder caused by the deficiency of α-galactosidase A. Despite recent advances in clinical and molecular characterization of FD, the pathophysiology of the GIS is still poorly understood. To shed light either on differential clinical presentation or on intervariability of GIS in FD, we genotyped 1936 genetic markers across 231 genes that encode for drug-metabolizing enzymes and drug transport proteins in 49 FD patients, using the DMET Plus platform. All nine single nucleotide polymorphisms (SNPs) mapped within four genes showed statistically significant differences in genotype frequencies between FD patients who experienced GIS and patients without GIS: ABCB11 (odd ratio (OR) = 18.07, P = 0,0019; OR = 8.21, P = 0,0083; OR=8.21, P = 0,0083; OR = 8.21, P = 0,0083),SLCO1B1 (OR = 9.23, P = 0,0065; OR = 5.08, P = 0,0289; OR = 8.21, P = 0,0083), NR1I3 (OR = 5.40, P = 0,0191) and ABCC5 (OR = 14.44, P = 0,0060). This is the first study that investigates the relationships between genetic heterogeneity in drug absorption, distribution, metabolism and excretion (ADME) related genes and GIS in FD. Our findings provide a novel genetic variant framework which warrants further investigation for precision medicine in FD

Evaluation of the students' perceptions about the virtual self-learning process in a postgraduate professional program

Objetivos: Evaluar la percepción de los estudiantes de postgrado sobre la enseñanza virtual en tres cuestiones básicas: acceso al conocimiento, grado de satisfacción y preferencia temporal en enseñanza virtual y presencial. Metodología: El estudio se realizó a través de un cuestionario con tres grupos de ítems vinculados a los objetivos arriba indicados. Se utilizó la prueba t de Student de doble cola. Resultados y Discusión: Para los alumnos, la plataforma virtual permite acceder al profesor sin llegar a sustituirlo (p=0,0000), e igual ocurre con la ampliación de conocimientos, la cual no sustituye a los libros ni a otras fuentes (p=0,0003) (p=0,0158). La libertad de horario constituye la percepción más valorada, superando significativamente a la dificultad de uso de la plataforma (p=0,0000), la modificación del horario extralaboral (p=0,0652), el estrés académico (p=0,0020) o la conciliación de la vida familiar y laboral (p=0,0016). Los estudiantes, a pesar de la accesibilidad y la satisfacción mostrada sobre la enseñanza virtual, asignan más porcentaje a la enseñanza presencial que a la virtual, tanto en teoría como en práctica (p=0,0000) y (p=0,0000).Objectives: To evaluate the perception of postgraduate students on virtual learning in three topics: access to knowledge, satisfaction level, and time-distribution preferences in virtual and non-virtual education. Methodology: This study was carried out by using a questionnaire with three groups of items associated with the 3 objectives. The Student t test was used to analyze the results. Results and Discussion: The virtual platform allowed the students to access the instructors, but without replacing them (p=0.0000). Also the student's perception is that they can increase their knowledge without replacing books or other resources (p=0.0003) (p=0.0158). The freedom of work time was significantly more valued that the need to overcome the difficulty of using the platform (p=0.0000), changing the working hours (p=0.0652), academic stress (p=0.0020) and balancing work and family life (p=0.0016). Despite the accessibility and satisfaction with the platform, students gave more percentage of time to non-virtual learning than to virtual learning in both theory and practice (p=0.0000) and (p=0.0000)

Violenza e conflitto

articoli selezionati in base ad un international call sui concetti di conflitto e violenz

Identification of Histological Patterns in Clinically Affected and Unaffected Palm Regions in Dupuytren's Disease

Dupuytren's disease is a fibro-proliferative disease characterized by a disorder of the extracellular matrix (ECM) and high myofibroblast proliferation. However, studies failed to determine if the whole palm fascia is affected by the disease. The objective of this study was to analyze several components of the extracellular matrix of three types of tissues—Dupuytren's diseased contracture cords (DDC), palmar fascia clinically unaffected by Dupuytren's disease contracture (NPF), and normal forehand fascia (NFF). Histological analysis, quantification of cells recultured from each type of tissue, mRNA microarrays and immunohistochemistry for smooth muscle actin (SMA), fibrillar ECM components and non-fibrillar ECM components were carried out. The results showed that DDC samples had abundant fibrosis with reticular fibers and few elastic fibers, high cell proliferation and myofibroblasts, laminin and glycoproteins, whereas NFF did not show any of these findings. Interestingly, NPF tissues had more cells showing myofibroblasts differentiation and more collagen and reticular fibers, laminin and glycoproteins than NFF, although at lower level than DDC, with similar elastic fibers than DDC. Immunohistochemical expression of decorin was high in DDC, whereas versican was highly expressed NFF, with no differences for aggrecan. Cluster analysis revealed that the global expression profile of NPF was very similar to DDC, and reculturing methods showed that cells corresponding to DDC tissues proliferated more actively than NPF, and NPF more actively than NFF. All these results suggest that NPF tissues may be affected, and that a modification of the therapeutic approach used for the treatment of Dupuytren's disease should be considered.This work was supported by CTS-115 (Tissue Engineering Group), University of Granada/Spain

Evaluación de las propiedades biomecánicas de tejidos artificiales elaborados con biopolímeros para su utilización en ingeniería tisular

Tesis Univ. Granada. Departamento de Histologí

Flame-Retardant Performance Evaluation of Functional Coatings Filled with Mg(OH)2 and Al(OH)3

In the shipbuilding sector (cruises, ferries, etc.), the design and control constraints applied to improve the fire safety conditions of naval vessels are acquiring important relevance. Research activities have aimed at enhancing the fire resistance of structures and surface coatings to make ships’ working environments safer, trying to combine performance, durability and low costs. In this context, the aim of this paper is to develop and optimize flame-retardant coatings for naval applications. In particular, in an acrylic carrier, Mg(OH)2 and Al(OH)3 fillers were added to exalt the fire resistance capabilities of the coatings. Furthermore, the effect of the particle size of the hydroxides on the coatings’ fire resistance was investigated. The coatings were studied by structural (XRD), thermo-physical (TG) and morphological (SEM) characterization to evaluate their thermal stability and the damage level due to fire exposition. Specifically, fire reaction tests were applied at different fire exposure times (15 s, 30 s) to estimate the fire resistance of the proposed coatings compared to the commercial reference. The results show that the coatings based on aluminum and magnesium hydroxides exhibit favorable fire resistance. Particularly, effective performances were observed for short times of exposure to direct flames. Furthermore, the temperature monitoring of the steel alloy support during the test allowed us to evaluate the degree of insulation of the coating, highlighting a better result for the specimen filled with Mg(OH)2, making this product promising for its optimization in this context

A machine learning approach for an HPC use case: The jobs queuing time prediction

High-Performance Computing (HPC) domain provided the necessary tools to support the scientific and industrial advancements we all have seen during the last decades. HPC is a broad domain targeting to provide both software and hardware solutions as well as envisioning methodologies that allow achieving goals of interest, such as system performance and energy efficiency. In this context, supercomputers have been the vehicle for developing and testing the most advanced technologies since their first appearance. Unlike cloud computing resources that are provided to the end-users in an on-demand fashion in the form of virtualized resources (i.e., virtual machines and containers), supercomputers’ resources are generally served through State-of-the-Art batch schedulers (e.g., SLURM, PBS, LSF, HTCondor). As such, the users submit their computational jobs to the system, which manages their execution with the support of queues. In this regard, predicting the behaviour of the jobs in the batch scheduler queues becomes worth it. Indeed, there are many cases where a deeper knowledge of the time experienced by a job in a queue (e.g., the submission of check-pointed jobs or the submission of jobs with execution dependencies) allows exploring more effective workflow orchestration policies. In this work, we focused on applying machine learning (ML) techniques to learn from the historical data collected from the queuing system of real supercomputers, aiming at predicting the time spent on a queue by a given job. Specifically, we applied both unsupervised learning (UL) and supervised learning (SL) techniques to define the most effective features for the prediction task and the actual prediction of the queue waiting time. For this purpose, two approaches have been explored: on one side, the prediction of ranges on jobs’ queuing times (classification approach) and, on the other side, the prediction of the waiting time at the minutes level (regression approach). Experimental results highlight the strong relationship between the SL models’ performances and the way the dataset is split. At the end of the prediction step, we present the uncertainty quantification approach, i.e., a tool to associate the predictions with reliability metrics, based on variance estimation