A Feasibility Study Of Fricke Dosimetry As An Absorbed Dose To Water Standard For 192ir Hdr Sources.

High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brachytherapy sources is presented in this study. The main goal of this paper is to demonstrate the potential usefulness of the Fricke dosimetry technique for the standardization of the quantity absorbed dose to water for 192Ir sources. A molded, double-walled, spherical vessel for water containing the Fricke solution was constructed based on the Fricke system. The authors measured the absorbed dose to water and compared it with the doses calculated using the AAPM TG-43 report. The overall combined uncertainty associated with the measurements using Fricke dosimetry was 1.4% for k = 1, which is better than the uncertainties reported in previous studies. These results are promising; hence, the use of Fricke dosimetry to measure the absorbed dose to water as a standard for HDR 192Ir may be possible in the future.9e11515

Torta de mamona no controle da broca-do-rizoma (Cosmopolites sordidus) em bananeira-Terra

Objetivou-se avaliar o efeito da torta de mamona sobre a infestação por Cosmopolites sordidus e o desenvolvimento de mudas de bananeira cultivar Terra. Avaliaram-se diferentes dosagens da torta de mamona (0 g, 12 g, 15 g, 18 g e 24 g) aplicadas a cada dois meses, a partir do plantio em mudas de bananeira dispostas num delineamento inteiramente casualizado, com dez repetições. Avaliou-se a evolução vegetativa das mudas pela altura da planta, pelo diâmetro do pseudocaule e pelo número de folhas verdes. Efetuou-se a infestação das plantas com 25 adultos de C. sordidus em cada muda. Os danos causados foram avaliados por meio da percentagem de galerias no rizoma, número de adultos vivos e mortos, número de larvas e número de pupas. Determinou-se também o efeito dos tratamentos sobre o valor de absorbância relativo ao teor de clorofila nas folhas por meio do uso de um clorofilômetro. Observou-se baixa infestação da broca-do-rizoma nas mudas tratadas com a torta de mamona. O crescimento e a absorbância foram afetados positivamente pela aplicação da torta de mamona. Assim, a torta de mamona reduz a população de C. sordidus nos rizomas de bananeira cv. Terra, favorece o crescimento das plantas e aumenta o valor de absorbância

Heat Shock Proteins in Glioblastoma Biology: Where Do We Stand?

Heat shock proteins (HSPs) are evolutionary conserved proteins that work as molecular chaperones and perform broad and crucial roles in proteostasis, an important process to preserve the integrity of proteins in different cell types, in health and disease. Their function in cancer is an important aspect to be considered for a better understanding of disease development and progression. Glioblastoma (GBM) is the most frequent and lethal brain cancer, with no effective therapies. In recent years, HSPs have been considered as possible targets for GBM therapy due their importance in different mechanisms that govern GBM malignance. In this review, we address current evidence on the role of several HSPs in the biology of GBMs, and how these molecules have been considered in different treatments in the context of this disease, including their activities in glioblastoma stem-like cells (GSCs), a small subpopulation able to drive GBM growth. Additionally, we highlight recent works that approach other classes of chaperones, such as histone and mitochondrial chaperones, as important molecules for GBM aggressiveness. Herein, we provide new insights into how HSPs and their partners play pivotal roles in GBM biology and may open new therapeutic avenues for GBM based on proteostasis machinery

Prion Protein at the Leading Edge: Its Role in Cell Motility

Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial–mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts

A New Take on Prion Protein Dynamics in Cellular Trafficking

The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis

Incluindo Funcionalidades no Modelo BRAMS para Simular o Transporte de Cinzas Vulcânicas: Descrição e Análise de Sensibilidade Aplicada ao Evento Eruptivo do Puyehue em 2011

Resumo Este trabalho possui dois objetivos principais, o primeiro é apresentar uma descrição de como o modelo atmosférico BRAMS foi estruturado com o intuito de capacitá-lo a simular a emissão, dispersão e sedimentação de cinzas vulcânicas; o segundo é fazer uma análise de sensibilidade com relação a diversas configurações do modelo, com o intuito de obter uma configuração adequada para prever a concentração de cinzas vulcânicas após eventos eruptivos. Avaliando os resultados do modelo com dados observados, principalmente com relação ao satélite CALIPSO, concluiu-se que o modelo BRAMS foi capaz de simular e prever com relativa precisão a posição e concentração das cinzas vulcânicas na atmosfera

Irradiation vessel drawings.

<p>a) External view of the flask. The lateral openings are used to insert and remove the solution. b) Cross-sectional view of the flask, with external and internal dimensions. A: ring-shaped disc (18 mm); B: source length (3.50 mm); C: source diameter (0.60 mm); D: source-holder diameter (1.06 mm); E and F: PMMA wall thicknesses (1.27 mm and 1.62 mm); G and H: internal and external diameter of the vessel (45.09 mm and 54.19 mm).</p

Numerical values of the coefficients for the aqueous 0.4 M H₂SO₄ used in the formalism proposed by Meesungnoen et al. [23].

<p>Numerical values of the coefficients for the aqueous 0.4 M H₂SO₄ used in the formalism proposed by Meesungnoen et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115155#pone.0115155-Meesungnoen1" target="_blank">[23]</a>.</p

Estimation of the <i>G value</i>.

<p>The <i>G value</i> was estimated based on published values and the use of the energy weights for the ¹⁹²Ir photon fluence calculated by MC simulations. Full circles are the values reported by Klassen et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115155#pone.0115155-Klassen2" target="_blank">[16]</a>, full squares are those reported by Fregene <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115155#pone.0115155-Fregene2" target="_blank">[25]</a>, and the solid line is all of the data fitted in this work.</p