A Flexible System for Simulating Aeronautical Telecommunication Network

At Old Dominion University, we have built Aeronautical Telecommunication Network (ATN) Simulator with NASA being the fund provider. It provides a means to evaluate the impact of modified router scheduling algorithms on the network efficiency, to perform capacity studies on various network topologies and to monitor and study various aspects of ATN through graphical user interface (GUI). In this paper we describe briefly about the proposed ATN model and our abstraction of this model. Later we describe our simulator architecture highlighting some of the design specifications, scheduling algorithms and user interface. At the end, we have provided the results of performance studies on this simulator

AlgiMatrix™ Based 3D Cell Culture System as an In-Vitro Tumor Model for Anticancer Studies

<div><h3>Background</h3><p>Three-dimensional (3D) in-vitro cultures are recognized for recapitulating the physiological microenvironment and exhibiting high concordance with in-vivo conditions. Taking the advantages of 3D culture, we have developed the in-vitro tumor model for anticancer drug screening.</p> <h3>Methods</h3><p>Cancer cells grown in 6 and 96 well AlgiMatrix™ scaffolds resulted in the formation of multicellular spheroids in the size range of 100–300 µm. Spheroids were grown in two weeks in cultures without compromising the growth characteristics. Different marketed anticancer drugs were screened by incubating them for 24 h at 7, 9 and 11 days in 3D cultures and cytotoxicity was measured by AlamarBlue® assay. Effectiveness of anticancer drug treatments were measured based on spheroid number and size distribution. Evaluation of apoptotic and anti-apoptotic markers was done by immunohistochemistry and RT-PCR. The 3D results were compared with the conventional 2D monolayer cultures. Cellular uptake studies for drug (Doxorubicin) and nanoparticle (NLC) were done using spheroids.</p> <h3>Results</h3><p>IC₅₀ values for anticancer drugs were significantly higher in AlgiMatrix™ systems compared to 2D culture models. The cleaved caspase-3 expression was significantly decreased (2.09 and 2.47 folds respectively for 5-Fluorouracil and Camptothecin) in H460 spheroid cultures compared to 2D culture system. The cytotoxicity, spheroid size distribution, immunohistochemistry, RT-PCR and nanoparticle penetration data suggested that in vitro tumor models show higher resistance to anticancer drugs and supporting the fact that 3D culture is a better model for the cytotoxic evaluation of anticancer drugs in vitro.</p> <h3>Conclusion</h3><p>The results from our studies are useful to develop a high throughput in vitro tumor model to study the effect of various anticancer agents and various molecular pathways affected by the anticancer drugs and formulations.</p> </div

Algimatrix 3D culture system.

<p>Scanning Electron Microscopic (SEM) images of 3D alginate scaffolds at lower resolution (left panel, 30 K) and higher resolution (right panel, 300 K), figure shows pore sizes in the matrix to accumulate the cells and grow them as spheroids (A). B) The schematic representation of 3D alginate scaffold wells and how spheroids are formed and grown in the 3D alginate scaffold cell culture system upon seeding the cells into the porous alginate media, C) Standard curve for H460 cells in AlamarBlue assay. Cells at different densities were incubated with AlamarBlue dye, after optimum incubation time point (4 h) fluorescence was measured at 530 and 570 excitation and emission, respectively.</p

Comparative growth characteristics of spheroids.

<p>Total spheroid number and size distribution of H1650 parental and stem cells in 3D algimatrix scaffolds 96 well plate format. The growth characteristics of H1650 parental cells (A) and H1650 stem cells (B) at IC₅₀ concentrations of various anticancer drugs (generated on H1650 parental cells).</p

Comparative analysis of IC₅₀ values of various anticancer drugs in 2D and 3D systems.

<p>Each data point is represented as mean ± sem (n = 4–5).</p>@<p>P<0.001 Vs respective 2D groups.</p

Immunohistochemistry and RT-PCR analysis.

<p>A) Representative images of immunohistochemistry of H1650 parental cells or spheroids grown in 2D and 3D culture systems for cleaved caspase positive cells and effect of Camptothecin and 5-Fluorouracil on cleaved caspase expression. Comparative Immunohistochemistry of B) H460 and C) H1650 parental cells or spheroids grown in 2D and 3D culture systems for cleaved caspase 3 positive cells. D) RT-PCR analysis of RNA isolated from 2D and 3D culture systems and effect of Docetaxel on Bcl-2 expression in H460 cells. The IC₅₀ concentration of Docetaxel 2D: 1.41 µM and 76.27 µM were used for treatment. Each data point is represented as mean ± sem (n = 3). *<0.05, **P<0.01 and ***P<0.001 Vs respective 2D groups.</p

Effect of anticancer agents in 3D system.

<p>A) Effect of Docetaxel on H460, A549, H1650 parental and stem lung tumor cells in 3D alginate scaffold system. B) Spheroid size distribution at the various concentrations of Docetaxel on H460 lung cells in 3D alginate scaffold system. Cytotoxicity of anticancer drugs (Cisplatin, Gemcitabine, 5-Fluorouracil and Camptothecin) in 3D alginate scaffold systems on C) H460 and D) A549 lung cancer cells. Each data point is represented as mean ± sem (n = 4–6).</p

Drug and nanoparticles uptake by spheroids.

<p>A) Representative images of Doxorubicin uptake in H1650 parental cell spheroids grown in 3D alginate scaffold system Uptake Images were taken at 0.5, 1 and 2 h time points, B) Representative Images of the nanoparticle uptake by H1650 parental cell spheroids. DIO oil was encapsulated in NLC and incubated with the spheroids for 2 hours, a) Fluorescent image, b) DIC image and c) merged image. The fluorescent images clearly indicates the nanoparticles uptake into spheroids, C) Relative fluorescence intensities of free Doxorubicin uptake and DIO oil loaded NLC nanoparticles into 3D spheroids. Each data point is represented as mean ± sem (n = 3). **P<0.01 Vs Doxorubicin group.</p