A Model for Predicting Magnetic Targeting of Multifunctional Particles in the Microvasculature

A mathematical model is presented for predicting magnetic targeting of multifunctional carrier particles that are designed to deliver therapeutic agents to malignant tissue in vivo. These particles consist of a nonmagnetic core material that contains embedded magnetic nanoparticles and therapeutic agents such as photodynamic sensitizers. For in vivo therapy, the particles are injected into the vascular system upstream from malignant tissue, and captured at the tumor using an applied magnetic field. The applied field couples to the magnetic nanoparticles inside the carrier particle and produces a force that attracts the particle to the tumor. In noninvasive therapy the applied field is produced by a permanent magnet positioned outside the body. In this paper a mathematical model is developed for predicting noninvasive magnetic targeting of therapeutic carrier particles in the microvasculature. The model takes into account the dominant magnetic and fluidic forces on the particles and leads to an analytical expression for predicting their trajectory. An analytical expression is also derived for predicting the volume fraction of embedded magnetic nanoparticles required to ensure capture of the carrier particle at the tumor. The model enables rapid parametric analysis of magnetic targeting as a function of key variables including the size of the carrier particle, the properties and volume fraction of the embedded magnetic nanoparticles, the properties of the magnet, the microvessel, the hematocrit of the blood and its flow rate.Comment: To appear in Journal of Magnetism and Magnetic Material

Continuous Magnetophoretic Separation of Blood Cells from Plasma at the Microscale

We present a method for the direct and continuous separation of red and white blood cells from plasma at the microscale. The method is implemented in a microfluidic system with magnetic functionality. The fluidic structure within the microsystem consists of an inlet and a single microfluidic channel with multiple outlets. The magnetic functionality is provided by an array of integrated soft-magnetic elements that are embedded transverse and adjacent to the microchannel. The elements are magnetized using an external field, and once magnetized they produce a magnetic force on blood cells as they flow through the microchannel. In whole blood, white blood cells (WBCs) behave as diamagnetic microparticles, while red blood cells (RBCs) exhibit diamagnetic or paramagnetic behavior depending on the oxygenation of their hemoglobin. We study the motion of blood cells through the microchannel using a mathematical model that takes into account the magnetic, fluidic and gravitational forces on the cells. We use the model to study blood cell separation, and our analysis indicates that the microsystem is capable of separating WBC-rich plasma, deoxygenated RBC-rich plasma and cell-depleted plasma into respective outlets.Comment: Submitted to Journal of Applied Physic

Gênero, conflito e liderança feminina na cidade pós-clássica: a atuação de Eudóxia e Olímpia sob o episcopado de João Crisóstomo (397-404)

Nesta dissertação, tivemos como objetivo investigar, no âmbito do Império Romano, a atuação das mulheres da aristocracia como importantes lideranças políticas na Capital do Oriente, Constantinopla. Como recorte específico, selecionamos um episódio marcante para a História da Igreja, o conflito irrompido após a deposição de João Crisóstomo, em 404, no qual partidários e inimigos do bispo se enfrentaram, gerando uma situação ímpar, na qual despontaram duas importantes figuras femininas: Eudóxia, imperatriz do Oriente; e Olímpia, uma diaconisa da igreja de Constantinopla. Defendemos que tanto a participação ativa de Eudóxia e Olímpia no conflito que levou João Crisóstomo ao exílio quanto a atuação feminina em situações do cotidiano, como no exercício dos ideais ascéticos, nas práticas de caridade por meio de doações financeiras, na assistência litúrgica, entre outras atividades que proporcionaram visibilidade ao elemento feminino, demonstram que as mulheres, na condição de sujeitos históricos, intervinham em diversas esferas da vida política, social e religiosa. Além disso, como benfeitoras de obras de caridade, seus recursos eram convertidos em edifícios e monumentos associados ao ethos cristão, de maneira que, por meio da sua atuação, contribuíam para o remodelamento da paisagem da cidade pós-clássica. Buscamos ainda aprofundar a compreensão acerca do contexto de exílio de João Crisóstomo, focando-nos, sobretudo, na relação mantida pelo bispo deposto com Olímpia. Na realização da pesquisa, exploramos um repertório documental extenso que incorpora o Diálogo sobre a vida de João Crisóstomo, de Paládio; as Histórias Eclesiásticas, de Sócrates e de Sozomeno; a História Nova, de Zósimo; o Epitáfio para João Crisóstomo e a Vida de Olímpia, ambos de autoria anônima; e a correspondência de exílio enviada por João a Olímpia, denominada Cartas a Olímpia. Na realização da pesquisa, nos valemos também da cultura material, com destaque para as moedas cunhadas por ou em honra a Eudóxia. Todos esses documentos nos permitiram refletir sobre a imagem e a atuação política das mulheres da aristocracia e sobre a maneira pela qual elas puderam interferir na dinâmica de Constantinopla no início do século V

Treatment effects of fixed functional appliances alone or in combination with multibracket appliances: A systematic review and meta-analysis

"Abstract Objective: To assess skeletal and dentoalveolar effects of fixed functional appliances, alone or in combination with multibracket appliances (comprehensive treatment), on Class II malocclusion in pubertal and postpubertal patients. Materials and Methods: Literature survey was conducted using the Medline, SCOPUS, LILACS, and SciELO databases and The Cochrane Library, and through a manual search. The studies retrieved had to have a matched untreated control group. No restrictions were set regarding the type of fixed appliance, treatment length, or to the cephalometric analysis used. Data extraction was mostly predefined at the protocol stage by two authors. Supplementary mandibular elongation was used for the meta-analysis. Results: Twelve articles qualified for the final analysis of which eight articles were on pubertal patients and four were on postpubertal patients. Overall supplementary total mandibular longationsas mean (95 confidence interval) were 1.95 mm (1.47 to 2.44) and 2.22 mm (1.63to 2.82) among pubertal patients and -1.73 mm (-2.60 to -0.86) and 0.44 mm (-0.78 to 1.66) among postpubertal patients, for the functional and comprehensive treatments, respectively. For pubertal subjects, maxillary growth restraint was also reported. Nevertheless, skeletal effects alone would not account for the whole Class II correction even in pubertal subjects with dentoalveolar effects always present. Conclusions: Fixed functional treatment is effective in treating Class II malocclusion with skeletal effects when performed during the pubertal growth phase, very few data are available on postpubertal patients.