Research

  • 18238
  • 0
  • Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns
    Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns
    Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing directions. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that are repellent to cancer cells but favourable for other types of cells., P. Premnath, et al., Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns, Exp Cell Res (2015), http://dx.doi.org/10.1016/j.yexcr.2015.07.028
    Turbo codes for multi-hop wireless sensor networks with decode-and-forward mechanism
    Turbo codes for multi-hop wireless sensor networks with decode-and-forward mechanism
    Wireless channels are prone to many impairments, such as noise and fading. Weak channels between the nodes in the wireless sensor network (WSN) can cause reception of erroneous packets. Retransmission mechanisms are mainly mused to tackle the problem of erroneous reception in WSN communication protocols. Weak channels can cause high number of retransmissions in order to deliver a packet correctly, which will consume high energy of both the transmitting and the receiving nodes. Error correcting codes (ECCs) can be used to reduce number of retransmissions, but most ECCs have complex decoding algorithms, which leads to high processing energy consumption at the receiving nodes in the WSN. In this paper, we present a low power consumption decode-and-forward approach for the multi-hop WSNs; a serial concatenation convolutional codes (SCCC) encoder is implemented at the source node while the complex iterative decoding algorithm is shifted to the sink (base station). The intermediate nodes run a Viterbi decoding algorithm to decode only the inner code of the SCCC encoder. We investigate the effect of changing constraint length of both the inner and the outer codes and the effect of changing encoding block size. We show that most packets can be decoded at the base station at low signal-to-noise ratio (SNR) channels with the penalty of small energy loss in decoding the packet at the nodes in the network., Abughalieh, N., Steenhaut, K., Nowé, A., & Anpalagan, A. (2014). Turbo codes for multi-hop wireless sensor networks with decode-and-forward mechanism. EURASIP Journal on Wireless Communications and Networking, 2014(1), 1-13.
    Two Kinds of A Priori Infallibility
    Two Kinds of A Priori Infallibility
    This paper is forthcoming in Synthese.
    Two-Dimensional Velocity Estimation for Doppler Optical Coherence Tomography
    Two-Dimensional Velocity Estimation for Doppler Optical Coherence Tomography
    Online version of a conference paper originally published as: Two-Dimensional Velocity Estimation for Doppler Optical Coherence Tomography, Darren Morofke, Michael C. Kolios, Victor X.D. Yang, Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI, edited by James G. Fujimoto, Joseph A. Izatt, Valery V. Tuchin Proc. of SPIE Vol. 6429, 64292F, (2007) Publisher URL: http://spie.org/x648.html?product_id=701372
    UAV Based Relay for Wireless Sensor Networks in 5G Systems
    UAV Based Relay for Wireless Sensor Networks in 5G Systems
    Relay is one of the most significant issues in smart industrial wireless sensor networks (WSN) due to the low transmitting power of sensors. By relay, the signals of sensors can be concentrated at the relay and further transmitted to the base station for decreasing energy consumption in the system. In the past decades, the relay in WSN is generally one super sensor with large transmitting power. However, the placement of the super sensor is static, which leads to the instability of performance in WSN under the time-varying wireless environment. Fortunately, unmanned aerial vehicles (UAV) can provide an effective leverage to improve the environment-adaptation in WSN compared to the static relay in WSN. In this paper, we employ UAV as the relay in WSN, which can move in three-dimensional space to possess a better position to minimize the system power consumption. We use a simple case study to demonstrate the effectiveness of UAV in WSN. Extended simulations are also given to verify the preferable performance of the UAV based relay in WSN., Fu, S., Zhao, L., Su, Z., & Jian, X. (2018). UAV based relay for wireless sensor networks in 5G systems. Sensors (Basel, Switzerland), 18(8), 2413., (This article belongs to the Special Issue Smart Industrial Wireless Sensor Networks)
    Ultrasound Backscatter Signal Characterization and Classification Using Autoregressive Modeling and Machine Learning Algorithms
    Ultrasound Backscatter Signal Characterization and Classification Using Autoregressive Modeling and Machine Learning Algorithms
    Online version of a conference paper originally published as: Ultrasound Backscatter Signal Characterization and Classification Using Autoregressive Modeling and Machine Learning Algorithms N.R. Farnoud, S. Krishnan and M.C. Kolios In Proceedings of the 25th Annual International Conference of the IEEE EMBS (2003), pp. 2861-2864 Publisher URL: http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=28615&arnumber=1280515&count=256&index=223
    Ultrasound Microbubble Treatment Enhances Clathrin-Mediated Endocytosis and Fluid-Phase Uptake through Distinct Mechanisms
    Ultrasound Microbubble Treatment Enhances Clathrin-Mediated Endocytosis and Fluid-Phase Uptake through Distinct Mechanisms
    Drug delivery to tumors is limited by several factors, including drug permeability of the target cell plasma membrane. Ultrasound in combination with microbubbles (USMB) is a promising strategy to overcome these limitations. USMB treatment elicits enhanced cellular uptake of materials such as drugs, in part as a result of sheer stress and formation of transient membrane pores. Pores formed upon USMB treatment are rapidly resealed, suggesting that other processes such as enhanced endocytosis may contribute to the enhanced material uptake by cells upon USMB treatment. How USMB regulates endocytic processes remains incompletely understood. Cells constitutively utilize several distinct mechanisms of endocytosis, including clathrin-mediated endocytosis (CME) for the internalization of receptor-bound macromolecules such as Transferrin Receptor (TfR), and distinct mechanism(s) that mediate the majority of fluid-phase endocytosis. Tracking the abundance of TfR on the cell surface and the internalization of its ligand transferrin revealed that USMB acutely enhances the rate of CME. Total internal reflection fluorescence microscopy experiments revealed that USMB treatment altered the assembly of clathrin-coated pits, the basic structural units of CME. In addition, the rate of fluid-phase endocytosis was enhanced, but with delayed onset upon USMB treatment relative to the enhancement of CME, suggesting that the two processes are distinctly regulated by USMB. Indeed, vacuolin-1 or desipramine treatment prevented the enhancement of CME but not of fluid phase endocytosis upon USMB, suggesting that lysosome exocytosis and acid sphingomyelinase, respectively, are required for the regulation of CME but not fluid phase endocytosis upon USMB treatment. These results indicate that USMB enhances both CME and fluid phase endocytosis through distinct signaling mechanisms, and suggest that strategies for potentiating the enhancement of endocytosis upon USMB treatment may improve targeted drug delivery., Fekri F, Delos Santos RC, Karshafian R, Antonescu CN (2016) Ultrasound Microbubble Treatment Enhances Clathrin-Mediated Endocytosis and Fluid-Phase Uptake through Distinct Mechanisms. PLoS ONE 11(6): e0156754. doi:10.1371/journal.pone.0156754
    Understanding Internet Usage Among Broadband Households: A Study of Household Internet Use Survey Data
    Understanding Internet Usage Among Broadband Households: A Study of Household Internet Use Survey Data
    Statistics Canada, Science, Innovation and Electronic Information Division Working Papers, Catalogue no. 88F0006X, no. 3, ISSN 1706-8967, ISBN 978-0-662-48548-3, Statistics Canada, Science, Innovation and Electronic Information Division Working Papers, Catalogue no. 88F0006X, no. 3, ISSN 1706-8967, ISBN 978-0-662-48548-3
    Undressing Fashion Metadata: Ryerson University Fashion Research Collection
    Undressing Fashion Metadata: Ryerson University Fashion Research Collection
    The purpose of this poster is to provide insight into the processes involved in making a unique fashion research and teaching collection discoverable in an online environment at Ryerson University. The online collection will provide a means for the users to identify what artifacts are available for research purposes and facilitate teaching in the classroom. The poster will highlight effective metadata standards and elements, cross-domain metadata uses, metadata mapping and implementation., Eichenlaub, N., Morgan, M., & Masak-Mida, I. (2014, October). Undressing Fashion Metadata: Ryerson University Fashion Research Collection. Proceedings of the International Conference on Dublin Core and Metadata Applications, 195-197. Retrieved from http://dcpapers.dublincore.org/pubs/article/view/3723/1946, Papers, Project Reports and Posters for DC-2014 in Austin, Texas, 8-11 October 2014
    Unmediated is the Message: Enhancements to Traditional Interlibrary Loan in a Canadian University
    Unmediated is the Message: Enhancements to Traditional Interlibrary Loan in a Canadian University
    Originally published in: Interlending & Document Supply, 32(3): 152-158. Publisher URL: http://www.emeraldinsight.com/10.1108/02641610410551978