Hypoxic Culture Conditions as a Solution for Mesenchymal Stem Cell Based Regenerative Therapy

Cell-based regenerative therapies, based on in vitro propagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability during in vitro expansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter-and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O-2 concentration (20%) in contrast to their niche where they usually reside in 2-9% O-2. Notably, O-2 plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O-2) and hypoxia (2-9% O-2) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors during in vitro expansion and eventually can increase efficiency of MSC-based regenerative therapies.Article Link: http://www.hindawi.com/journals/tswj/2013/632972

Key Factors Influencing Students\u27 Post-Triability Intention to Adopt E-Textbooks in a Medium-Size University

In recent years, E-textbooks have become a real alternative to the traditional textbooks in higher education. Many institutions have been encouraging their usage with mixed success. This study investigates students’ perceptions of E-textbooks in a medium-sized university in the Midwestern United States and measures students’ intention to adopt E-textbooks where they had an option to choose between traditional textbooks and E-textbooks for their classes. Literature reviews indicated some inconsistencies related to E-textbook adoptions. We used the Technology Acceptance model to investigate these inconsistencies. We considered three factors in this study: Perceived Ease of Use, Perceived Values, and Technology-Savvy. An E-textbook adoption model is proposed, and we used an online survey to collect data among students on campus. In this study we focus on those students who have tried E-textbooks in at least one of their classes and assess their intention to adopt. This study confirms that the Perceived Ease of Use is a critical factor to consider for the successful adoption of E-textbooks

Understanding Coarsening for Embedding Large-Scale Graphs

A significant portion of the data today, e.g, social networks, web connections, etc., can be modeled by graphs. A proper analysis of graphs with Machine Learning (ML) algorithms has the potential to yield far-reaching insights into many areas of research and industry. However, the irregular structure of graph data constitutes an obstacle for running ML tasks on graphs such as link prediction, node classification, and anomaly detection. Graph embedding is a compute-intensive process of representing graphs as a set of vectors in a d-dimensional space, which in turn makes it amenable to ML tasks. Many approaches have been proposed in the literature to improve the performance of graph embedding, e.g., using distributed algorithms, accelerators, and pre-processing techniques. Graph coarsening, which can be considered a pre-processing step, is a structural approximation of a given, large graph with a smaller one. As the literature suggests, the cost of embedding significantly decreases when coarsening is employed. In this work, we thoroughly analyze the impact of the coarsening quality on the embedding performance both in terms of speed and accuracy. Our experiments with a state-of-the-art, fast graph embedding tool show that there is an interplay between the coarsening decisions taken and the embedding quality.Comment: 10 pages, 6 figures, submitted to 2020 IEEE International Conference on Big Dat

In-Flight Learning Based Flight Control of an Unmanned Aircraft System

Title from PDF of title page viewed June 3, 2019Dissertation advisor: Travis FieldsVitaIncludes bibliographical references (pages 128-137)Thesis (PH.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2018Unmanned Aerial Vehicles (UAVs) popularity has increased substantially in the last few years. UAVs capabilities continue to improve as a result of advances in battery technology, communication, navigation systems and electronics. Increased popularity has driven researchers to improve UAVs reliability and safety which is reflected by the number of publications and accelerating educational programs interest. UAVs are suited for a wide range of civilian and military applications; however, UAVs currently can not integrate with civilian airspace because of stringent safety requirements. Hence, it is necessary to push the envelope for UAVs design and control so that they can learn from nature and have more self-aware capabilities to improve safety and reliability. This dissertation addresses some challenges involved with flight controller learning based on real-time modeling of UAV. Plenty of UAV applications require different operational capabilities within a composite mission. These capabilities include landing and taking off using short runways, while being able to perform missions that require a high cruise speed i.e. tracking applications. A composite mission also requires the aircraft to be able to hover or operate with low cruise speeds for applications involving stationary moments. All of these different operational modes require a hybrid aircraft design that combines fixed wing aircraft capabilities and Vertical Take-Off and Landing (VTOL) aircraft capabilities. However, extensive resources required for hybrid aircraft design prohibited the discovery of different revolutionary designs. The work presented in this dissertation describes the development of a rapid modeling, prototyping and controller design platform of an unmanned quadrotor aircraft. Three main objectives are investigated: intelligent excitation input design, real-time parameter estimation, and learning control. Real-time estimation of dynamic model parameters is important for control adaptation. However, the aircraft model estimation performance can be severely degraded by an active control system and highly collinear model terms such as those found on a quadrotor unmanned aircraft. Recursive Fourier Transform Regression was applied to estimate parameters of different model forms/structures and using different excitation levels. The generated models are utilized to reconfigure a Nonlinear Dynamic Inversion (NDI) controller considering different testing conditions: normal, failure, and learning flights. Finally,an intelligent input design technique is proposed which enables autonomous identification of the vehicle’s response modal frequencies and emphasizes excitation power accordingly.Introduction -- Literature review -- Real-time closed loop system identification of a Quad-copter -- Flight controller learning based on real-time model estimation of a quadrotor aircraft -- Unmanned aircraft system intelligent system identification experiment design -- Conclusion and future work -- Appendix A. Power spectrum of a multisine signal -- Appendix B. Power spectrum of a multisine signa

A Systematic Review of Personal Information Sharing in Smart Cities: Risks, Impacts, and Controls

AbstractSmart cities aim to deliver smart services that rely on emerging technologies to their users. In order for users to get the provided services, they need to share their personal information with different parties. However, sharing personal information in smart cities may impact the privacy of that information. Thus, there is a need to address privacy risks relevant to sharing personal information in smart cities. This study aims to address this issue by conducting a systematic literature review (SLR) to identify and extract privacy risks, impacts, and existing controls associated with sharing personal information, considering elements involved and interacting during the sharing activity in smart cities. A set of 83 selected studies in both academic and industry fields were reviewed, and the results were categorised into three main groups: privacy risks, impacts, and controls. Moreover, the implications and future research directions were also reported. The proposed privacy risk taxonomy will provide a much-needed foundation for the industry and research community, intending to research and evaluate privacy risk frameworks and design solutions for sharing personal information in smart cities.</jats:p

Hypoxic Culture Conditions as a Solution for Mesenchymal Stem Cell Based Regenerative Therapy

Cell-based regenerative therapies, based on in vitro propagation of stem cells, offer tremendous hope to many individuals suffering from degenerative diseases that were previously deemed untreatable. Due to the self-renewal capacity, multilineage potential, and immunosuppressive property, mesenchymal stem cells (MSCs) are considered as an attractive source of stem cells for regenerative therapies. However, poor growth kinetics, early senescence, and genetic instability during in vitro expansion and poor engraftment after transplantation are considered to be among the major disadvantages of MSC-based regenerative therapies. A number of complex inter- and intracellular interactive signaling systems control growth, multiplication, and differentiation of MSCs in their niche. Common laboratory conditions for stem cell culture involve ambient O2 concentration (20%) in contrast to their niche where they usually reside in 2–9% O2. Notably, O2 plays an important role in maintaining stem cell fate in terms of proliferation and differentiation, by regulating hypoxia-inducible factor-1 (HIF-1) mediated expression of different genes. This paper aims to describe and compare the role of normoxia (20% O2) and hypoxia (2–9% O2) on the biology of MSCs. Finally it is concluded that a hypoxic environment can greatly improve growth kinetics, genetic stability, and expression of chemokine receptors during in vitro expansion and eventually can increase efficiency of MSC-based regenerative therapies

Untersuchungen zu Fragen der Schnitt- und Weidenutzung in Abhängigkeit von Düngungsintensität und Grünlandstandort

Im Zeitraum von 1999 bis 2006 wurden auf zwei früher intensiv bewirtschafteten Versuchstandorten in Nordostdeutschland langjährige Vergleiche zwischen Schnittnutzung und Weidenutzung unter der Bedingung extensiver- und halbintensiver Düngungsvarianten geführt. Es handelt sich um faktorielle Versuchsanlagen mit den Faktoren A: Nutzung (dreimalige Schnittnutzung, drei- bis viermalige Weidenutzung) und B: Düngung (12 Stufen) in dreifacher Wiederholung auf tiefgründigem Niedermoor bzw. (10 Düngungsstufen) in vierfacher Wiederholung auf lehmigem Sandboden

Cytolytic effects and apoptosis induction of newcastle disease virus strain AF2240 on anaplastic astrocytoma brain tumor cell line.

Newcastle disease virus (NDV) is a member of genus Avulavirus within the family Paramyxoviridae. Interest of using NDV as an anticancer agent has arisen from its ability to kill tumor cells with limited toxicity to normal cells. In this investigation, the cytotolytic properties of NDV strain AF2240 were evaluated on brain tumor cell line, anaplastic astrocytoma (U-87MG), by using MTT assay. Cytological observations were studied using fluorescence microscopy and transmission electron microscopy to show the apoptogenic features of NDV on U-87MG. DNA laddering in agarose gel electrophoresis and terminal deoxyribonucleotide transferase-mediated dUTP-X nick end-labeling staining assay confirmed that the mode of cell death was by apoptosis. However, analysis of the cellular DNA content by flowcytometery showed that there was a loss of treated U-87MG cells in all cell cycle phases (G1, S and G2/M) accompanied with increasing in sub-G1 region (apoptosis peak). Early apoptosis was observed 6 h post-inoculation by annexin-V flow-cytometry method. It could be concluded that NDV strain AF2240 is a potent antitumor agent that induce apoptosis and its cytotoxicity increasing while increasing of time and virus titer

Prevalence of anelloviruses (TTV, TTMDV, and TTMV) in healthy blood donors and in patients infected with HBV or HCV in Qatar

Background Anelloviruses (TTV, TTMV, and TTMDV) have been associated with non A-G hepatitis. The goal of the current study was to estimate the prevalence of these anelloviruses in Qatar. Methods A total of 607 blood samples (500 healthy donors, and 53 HBV-and 54 HCV-positive patients) representing different nationalities were tested for the presence of TTV, TTMV, and TTMDV DNA by nested PCR. Results Prevalence rates for the three viruses were high in all studied groups, and exceeding 95% in the HBV group (for TTV and TTMDV). Infection with more than one type of viruses was common and significant in most of the positive patients (p  0.05) albeit the detection of higher infection rates among females and Qatari subjects. Conclusion This was the first published study to look at prevalence of Anellowviruses in the Middle East. High prevalence rates of the three viruses in all studied groups was noted. Further studies are needed to explore and compare the different genotypes of these viruses in the region.This work was made possible by UREP grant # (UREP 15-015-3-006) from the Qatar National Research Fund (a member of Qatar Foundation)