Squeeze flow magnetorheology

This paper is concerned with an investigation of the rheological performance of magnetorheological fluids under squeeze flow. Preliminary results on Newtonian fluids are first compared to Stefan’s equation. Then, unidirectional monotonic compression tests are carried out in the presence of uniaxial external magnetic fields at slow compression rates under constant volume operation. Results are compared to Bingham plastic, biviscous, and single chain micromechanical squeeze flow models. Measurements using combined deformation modes (compression+small-strain oscillatory shear) suggest a compression-induced shear strengthen effect up to strains of ∼0.5. Particle-level dynamic simulations are in qualitatively good agreement with experimental observations

Specific ion effects on the electrokinetic properties of iron oxide nanoparticles: Experiments and simulations

We report experimental and simulation studies on ion specificity in aqueous colloidal suspensions of positively charged, bare magnetite nanoparticles. Magnetite has the largest saturation magnetization among iron oxides and relatively low toxicity, which explain why it has been used in multiple biomedical applications. Bare magnetite is hydrophilic and the sign of the surface charge can be changed by adjusting the pH, its isoelectric point being in the vicinity of pH = 7. Electrophoretic mobility of our nanoparticles in the presence of increasing concentrations of different anions showed that anions regarded as kosmotropic are more efficient in decreasing, and even reversing, the mobility of the particles. If the anions were ordered according to the extent to which they reduced the particle mobility, a classical Hofmeister series was obtained with the exception of thiocyanate, whose position was altered. Monte Carlo simulations were used to predict the diffuse potential of magnetite in the presence of the same anions. The simulations took into account the ion volume, and the electrostatic and dispersion forces among the ions and between the ions and the solid surface. Even though no fitting parameters were introduced and all input data were estimated using Lifshitz theory of van der Waals forces or obtained from the literature, the predicted diffusion potentials of different anions followed the same order as the mobility curves. The results suggest that ionic polarizabilities and ion sizes are to a great extent responsible for the specific ion effects on the electrokinetic potential of iron oxide particles.The authors thank the financial support from the following institutions: (i) ‘Ministerio de Economía y Competitividad, Plan Nacional de Investigación, Desarrollo e Innovación Tecnológica (I + D + i)’, Projects MAT2013-44429-R, MAT2012-36270-C04-04 and -02. (ii) ‘Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía’, Projects P09-FQM-4698, P10-FQM-5977, and P11-FQM-7074. (iii) European Regional Development Fund (ERDF)

Start-up rheometry of highly polydisperse magnetorheological fluids: experiments and simulations

An extensive experimental and simulation study is carried out in conventional magnetorheological fluids formulated by dispersion of mixtures of carbonyl iron particles having different sizes in Newtonian carriers. Apparent yield stress data are reported for a wide range of polydispersity indexes (PDI) from PDI = 1.63 to PDI = 3.31, which for a log-normal distribution corresponds to the standard deviation ranging from to . These results demonstrate that the effect of polydispersity is negligible in this range in spite of exhibiting very different microstructures. Experimental data in the magnetic saturation regime are in quantitative good agreement with particle-level simulations under the assumption of dipolar magnetostatic forces. The insensitivity of the yield stresses to the polydispersity can be understood from the interplay between the particle cluster size distribution and the packing density of particles inside the clusters

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

Sperm DNA fragmentation: A new guideline for clinicians

Sperm DNA integrity is crucial for fertilization and development of healthy offspring. The spermatozoon undergoes extensive molecular remodeling of its nucleus during later phases of spermatogenesis, which imparts compaction and protects the genetic content. Testicular (defective maturation and abortive apoptosis) and post-testicular (oxidative stress) mechanisms are implicated in the etiology of sperm DNA fragmentation (SDF), which affects both natural and assisted reproduction. Several clinical and environmental factors are known to negatively impact sperm DNA integrity. An increasing number of reports emphasizes the direct relationship between sperm DNA damage and male infertility. Currently, several assays are available to assess sperm DNA damage, however, routine assessment of SDF in clinical practice is not recommended by professional organizations

Effects of Once-Weekly Exenatide on Cardiovascular Outcomes in Type 2 Diabetes.

Abstract BACKGROUND: The cardiovascular effects of adding once-weekly treatment with exenatide to usual care in patients with type 2 diabetes are unknown. METHODS: We randomly assigned patients with type 2 diabetes, with or without previous cardiovascular disease, to receive subcutaneous injections of extended-release exenatide at a dose of 2 mg or matching placebo once weekly. The primary composite outcome was the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The coprimary hypotheses were that exenatide, administered once weekly, would be noninferior to placebo with respect to safety and superior to placebo with respect to efficacy. RESULTS: In all, 14,752 patients (of whom 10,782 [73.1%] had previous cardiovascular disease) were followed for a median of 3.2 years (interquartile range, 2.2 to 4.4). A primary composite outcome event occurred in 839 of 7356 patients (11.4%; 3.7 events per 100 person-years) in the exenatide group and in 905 of 7396 patients (12.2%; 4.0 events per 100 person-years) in the placebo group (hazard ratio, 0.91; 95% confidence interval [CI], 0.83 to 1.00), with the intention-to-treat analysis indicating that exenatide, administered once weekly, was noninferior to placebo with respect to safety (P<0.001 for noninferiority) but was not superior to placebo with respect to efficacy (P=0.06 for superiority). The rates of death from cardiovascular causes, fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, hospitalization for heart failure, and hospitalization for acute coronary syndrome, and the incidence of acute pancreatitis, pancreatic cancer, medullary thyroid carcinoma, and serious adverse events did not differ significantly between the two groups. CONCLUSIONS: Among patients with type 2 diabetes with or without previous cardiovascular disease, the incidence of major adverse cardiovascular events did not differ significantly between patients who received exenatide and those who received placebo. (Funded by Amylin Pharmaceuticals; EXSCEL ClinicalTrials.gov number, NCT01144338 .)

Impulsos iniciales de la modernización autoritaria en Granada: el Ayuntamiento de los Asociados y el marqués de Casablanca (1923-1924)

The coup d’état that led to the dictatorship of Primo de Rivera had the support of the social and economic institutions of Granada and the entire local press, which considered it a project of renewal against the oligarchic system and local despotism. The constitutional City Council was dissolved, constituting another with the associated members who had been previously chosen by lot among the direct taxpayers of the city. The new City Council elected as mayor-president José Tripaldi Herrera who did not accept the position. Then, the military Directory co-opted to Antonio Díez de Rivera and Muro, XI Marquis of Casablanca and retired general of Artillery. The initial regenerationist impulse of this City Council, formed mostly by neighbors without any political ambition, was noted until the enactment of the Municipal Statute in March 1924. For the Marquis of Casablanca, the priority was to pay the accumulated debt and thus recover the credit before society and banks, honestly managing the budget.El golpe de Estado que condujo a la dictadura de Primo de Rivera contó con el apoyo de las instituciones sociales y económicas de Granada y de toda la prensa local, que lo consideró un proyecto de renovación frente al sistema oligárquico y caciquil imperante. El Ayuntamiento constitucional fue disuelto, constituyéndose otro con sus vocales asociados que habían sido elegidos por sorteo entre los contribuyentes directos de la ciudad. El nuevo Ayuntamiento eligió alcalde-presidente a José Tripaldi Herrera quien no aceptó el cargo. El gobierno del Directorio militar cooptó entonces a Antonio Díez de Rivera y Muro, XI marqués de Casablanca y general retirado de Artillería. El impulso inicial regeneracionista de este Ayuntamiento, formado en su mayoría por vecinos sin ninguna ambición política, se dejó notar hasta la promulgación del Estatuto Municipal en marzo de 1924. Para el marqués de Casablanca la prioridad fue pagar la deuda acumulada y así recuperar el crédito ante la sociedad y las entidades bancarias, administrando con honestidad el presupuesto

La modernidad impulsada desde el poder local: saneamiento económico y aguas potables en Granada (1924-1928).

This article analyzes the main modernizing projects promoted by the City Council of Granada constituted under the Municipal Statute of 1924. The City Council cleared up the accounts, paid outstanding debts and set the sewerage, water supply, and water treatment project as a priority. For this, it introduced a new tax collection. The water project, however, generated serious internal conflicts into the power bloc that had led the Marquis of Casablanca to be the Mayor of Granada. That project began at the end of 1923 and culminated with the approval by the majority of one of the two solutions proposed by the Jury in the summer of 1927. The decision generated a political crisis that was resolved with the forced resignation of the ten councilors who did not vote with the Mayor and the Duke of San Pedro de Galatino was fined for disseminating chemical and bacteriological analyzes that questioned the potability of the waters of the upper Genil river basin. The acceptance of the project by the Central Board of Health occurred four years after the approval of the Statute. After overcoming all the challenges presented to the project, the Marquis of Casablanca resigned due to poor health in August 1928.El artículo analiza los principales proyectos modernizadores impulsados por el Ayuntamiento de Granada constituido mediante el Estatuto Municipal de 1924. El Ayuntamiento saneó sus cuentas, pagó deudas pendientes y fijó como prioridad el proyecto de alcantarillado, abastecimiento y potabilización de las aguas. Para ello implantó nuevos arbitrios y mejoró su recaudación. El proyecto de las aguas generó serios conflictos internos al bloque de poder que había llevado al marqués de Casablanca a la alcaldía.  El proyecto se inició a finales de 1923 y culminó con la aprobación de una de las dos soluciones propuestas por el Jurado en el verano de 1927. La decisión generó una crisis política y la dimisión obligada de los diez concejales que no votaron con el alcalde, así como una multa extrarreglamentaria al duque de San Pedro de Galatino por difundir unos análisis químicos y bacteriológicos que cuestionaban la potabilidad de las aguas de la cuenca alta del río Genil. La aceptación del proyecto por la Junta Central de Sanidad se produjo cuatro años después de la aprobación del Estatuto. Tras las impugnaciones al proyecto, que fueron rechazadas por el Ayuntamiento, el marqués de Casablanca dimitía por problemas de salud en agosto de 1928

Jesús Yoldi Bereau (1894-1936), el profesor de Química que no se presentó a su destino

Jesús Yoldi Bereau fue catedrático de Química General en la Facultad de Ciencias de la Universidad de Granada desde 1924 hasta 1936. Socio fundador y vocal de la Sección Local de la Sociedad Española de Física y Química desde 1930, Jesús Yoldi fue miembro de la Junta de Gobierno de la Universidad desde 1931 y alcalde de la ciudad en 1932. Fusilado el 23 de octubre de 1936 por los militares subleva- dos contra la República, silencio y olvido cayeron sobre el profesor Yoldi. Este artículo quiere recuperar la memoria de quien fue destacado profesor de Química y ejemplo de compromiso político y social, durante aquellos años en los que se truncó la llamada Edad de Plata de la ciencia española.Jesús Yoldi Berau was professor of General Chemistry within the Faculty of Sciences at Granada University from 1924 to 1936. He was founder fellow and member of the board of the Local Section of the Spanish Society of Physics and Chemistry from 1930, member of the Governing Board of Granada University from 1931 and major of the city in 1932. Professor Yoldi was executed on October 23, 1936 in the military revolt against the Republic and since then his figure has fallen into oblivion and silence. This article aims to recover the memory of a distinguished professor of chemistry and an example of political and social commitment, during those years the so-called Silver Age of the Spanish science was axed