40 research outputs found
Unmanned Aerial Systems: Future Military and Commercial Outgrowth in the Canadian Context
No full textUnmanned aerial systems (UAS) have been a source of controversy over the last decade for their role in killing suspected militants in the Middle East and Northern Africa. However, they are also making headlines for their commercial applications in various civilian industries. Regardless of how they have been utilized, UAS technology is proliferating rapidly across the globe and it is being extensively developed by democratic and non-democratic nations alike. This paper provides a comprehensive overview of the outgrowth of military and commercial UAS in Canada, their ideal use for its democratic military as well as its commercial industry growth. The first half of the paper will illustrate the history of unmanned vehicles and their evolution into the systems we know today. Adding to this, the author will illustrate what military UAS entail as well as their current uses in the Canadian armed forces. Further, it will be explained how UAS are well-suited to western militaries for use in their asymmetric democratic wars of choice. The second half of the article will focus on UAS in the commercial industry with a specific focus on the Canadian context. Current federal regulations that govern the use of UAS as well as the regulatory challenges surrounding them will be highlighted in order to emphasize how clear federal regulations can facilitate the industry‘s growth. Further, this paper will detail the various key commercial sectors of the Canadian economy where UAS can be beneficial.
By summarizing the military uses of UAS in Canada, this author will attempt to argue that in line with current democratic trends and global usage, the utilization of UAS by the Canadian military will expand in accordance with the current government‘s political commitments as outlined in the Canada First Defense Strategy. Further, by detailing the commercial UAS industry and the ways it can benefit key Canadian commercial sectors, this author will demonstrate that maintaining regulatory pace with UAS industry growth satisfies Canada‘s economic priorities as outlined in "Canada‘s Economic Action Plan"
Unmanned Aerial Systems: Future Military and Commercial Outgrowth in the Canadian Context
No full textUnmanned aerial systems (UAS) have been a source of controversy over the last decade for their role in killing suspected militants in the Middle East and Northern Africa. However, they are also making headlines for their commercial applications in various civilian industries. Regardless of how they have been utilized, UAS technology is proliferating rapidly across the globe and it is being extensively developed by democratic and non-democratic nations alike. This paper provides a comprehensive overview of the outgrowth of military and commercial UAS in Canada, their ideal use for its democratic military as well as its commercial industry growth. The first half of the paper will illustrate the history of unmanned vehicles and their evolution into the systems we know today. Adding to this, the author will illustrate what military UAS entail as well as their current uses in the Canadian armed forces. Further, it will be explained how UAS are well-suited to western militaries for use in their asymmetric democratic wars of choice. The second half of the article will focus on UAS in the commercial industry with a specific focus on the Canadian context. Current federal regulations that govern the use of UAS as well as the regulatory challenges surrounding them will be highlighted in order to emphasize how clear federal regulations can facilitate the industry‘s growth. Further, this paper will detail the various key commercial sectors of the Canadian economy where UAS can be beneficial.
By summarizing the military uses of UAS in Canada, this author will attempt to argue that in line with current democratic trends and global usage, the utilization of UAS by the Canadian military will expand in accordance with the current government‘s political commitments as outlined in the Canada First Defense Strategy. Further, by detailing the commercial UAS industry and the ways it can benefit key Canadian commercial sectors, this author will demonstrate that maintaining regulatory pace with UAS industry growth satisfies Canada‘s economic priorities as outlined in "Canada‘s Economic Action Plan"
The Dispute over the Role of History in the Public Sphere in Contemporary Ukraine
No full textThis article discusses the debate over the social meaning of history occurring between proponents and opponents of the national paradigm in contemporary Ukrainian historiography, in the context of recent paradigmatic changes in historiography in the West. The debate centers on two competing views of the proper relation of academic history writing to politics and society. After pointing out the limitations of these two dominant perspectives, the author ends the article by discussing possible solutions, particularly John Tosh’s idea of a critical public history, which is practiced in Ukraine by Jarosław Hrycak
Spory o rolę historii w sferze publicznej na współczesnej Ukrainie
No full textThis article discusses the debate over the social meaning of history occurring between proponents and opponents of the national paradigm in contemporary Ukrainian historiography, in the context of recent paradigmatic changes in historiography in the West. The debate centers on two competing views of the proper relation of academic history writing to politics and society. After pointing out the limitations of these two dominant perspectives, the author ends the article by discussing possible solutions, particularly John Tosh’s idea of a critical public history, which is practiced in Ukraine by Jarosław Hrycak
Influence of adenovirus-specific immune responses on adenovirus-based immunization
No full textAd5-basierte Impfvektoren werden aufgrund ihrer hohen Immunogenität geschätzt, obwohl diese gleichzeitig ihren klinischen Nutzen limitieren kann. Bei Studien im Friend Virus-Modell wurde beobachtet, dass nach Immunisierung mit Ad5.Leader-Gag, der für das FV Leader-Gag-Protein mit dem darin enthaltenen, immundominanten CD8+ T Zell-Epitop GagL85-93 kodiert, keine CD8+ T Zellantworten induziert werden. Die Immunisierung mit einem Leader-Gag-kodierenden DNA-Plasmid resultierte hingegen in der Induktion GagL85-93-spezifischer CD8+ T Zellantworten, während in einem weiteren Experiment keine GagL85-93-spezifischen CD8+ T Zellen detektiert werden konnten, wenn das Plasmid neben GagL85 93 die beiden adenoviralen CD8+ T Zell-Epitope DBP418-426 und Hexon486-494 kodierte. Diese Ergebnisse unterstrichen einen suppressiven Effekt adenoviraler Epitope auf die Induktion Transgen-spezifischer CD8+ T Zellantworten, der in dieser Arbeit näher untersucht wurde.
Während das H2 Db-restringierte DBP418 426 keinen negativen Einfluss auf die Induktion GagL85-93(H2 Db)-spezifischer CD8+ T Zellen hatte, wurde GagL85-93 vor allem durch das H-2Dd-restringierte Hexon486-494-Epitop dominiert. Da in H2 Db/b-Mäusen keine Immundominanz des Hexon486 494-Epitops über GagL85-93 festgestellt wurde, ließ sich auf die Konkurrenz aktivierter CD8+ T Zellen schließen. Durch Co-Immunisierung mit IL2- oder IL23-kodierenden DNA-Plasmiden konnte die Hexon486-494-bedingte Suppression GagL85 93-spezifischer CD8+ T Zellen partiell aufgehoben werden. Im Gegensatz dazu resultierte weder die Co-Immunisierung mit IL2- oder IL23-kodierenden Ad5-Vektoren, noch die Immunisierung von H2-Db/b-Mäusen mit Ad5.Leader-Gag in der Induktion GagL85 93-spezifischer CD8+ T Zellen. Dies wurde dem Vorkommen weiterer dominanter Epitope im Ad5-Vektor beigemessen und konnte mittels ELISpot-Assay bestätigt werden. Mithilfe der OVA-abgeleiteten Epitope Y3, Q4 und T4 wurde zudem gezeigt, dass eine Immunisierung mit schwächeren Transgen-kodierten Epitopen in stärkeren Ad5-spezifischen CD8+ T Zellantworten resultierte.
Neben Vektor-induzierten Immunantworten wird die Effektivität Ad5-basierter Vektoren durch die weit verbreitete Ad5-Prä-Immunität beeinträchtigt. In Ad5-prä-immunen Mäusen konnten demgemäß nach Immunisierung mit Ad5.TxnGagL keine GagL85-93-spezifischen CD8+ T Zellen induziert werden. Eine Publikation über den Anstieg Transgen-bindender Antikörpertiter in Ad5-prä-immunen Mäusen widersprach jedoch einer vollständigen Eliminierung des Ad5-Vektors durch neutralisierende Antikörper und deutete auf fortlaufende Transgen-Expression hin. In eigenen Experimenten wurde kein negativer Einfluss Ad5-spezifischer CD4+ oder CD8+ T-Zellen auf die Induktion Transgen-spezifischer CD8+ T Zellantworten nachgewiesen, während GagL85-93-spezifische CD8+ T Zellantworten nach dem Transfer von Plasma aus Ad5-prä-immunen Mäusen inhibiert wurden. Weitere Versuche zeigten, dass Ad5-bindende Antikörper die Induktion Transgen-spezifischer CD8+ T Zellen nicht beeinträchtigten und eine Rolle bei der erhöhten Antikörperinduktion spielen könnten.
Aufgrund ihrer phylogenetischen Unterschiede zu Ad5 wird angenommen, dass seltene Adenovirus-Typen von Ad5-neutralisierenden Antikörpern nicht beeinträchtigt werden. In dieser Arbeit wurden daher Vektoren basierend auf den seltenen Adenovirus-Typen Ad48 und Ad50 als Alternativen zu Ad5 evaluiert. Ad48- und Ad50-basierte Vektoren waren nur hinreichend zur Induktion Transgen-spezifischer CD8+ T Zellantworten geeignet. Durch Immunisierung mit Ad48.Leader-GagC1K oder Ad50.Env konnte dennoch ein vergleichbarer Schutz vor einer FV Infektion erzielt werden, wie nach der Immunisierung mit dem entsprechenden Ad5-Konstrukt. Dieser Schutz basierte vermutlich auf der Induktion von CD4+ T Zell- und Antikörperantworten. Die Immunisierung mit Ad48 und Ad50-Vektoren induzierte allerdings Vektor-neutralisierende Antikörperantworten, die gegen beide Typen kreuzreaktiv waren. Prä-Immunität gegen Ad5 beeinflusste die Immunisierung mit Ad48-Vektoren nicht negativ. Im Gegensatz dazu war die Effektivität Ad50-basierter Vektoren in Ad5-prä-immunen Mäusen, vermutlich aufgrund kreuzreaktiver Antiköper, ähnlich eingeschränkt, wie die von Ad5-basierten Vektoren.
Anti-Vektor-Immunität kann sowohl in Form von Vektor-induzierter Immunität als auch von Prä-Immunität gegen Ad5 maßgeblich den Ausgang Adenovirus-basierter Impfungen beeinflussen. Die Ergebnisse dieser Arbeit unterstreichen die Notwendigkeit einer gründlichen Charakterisierung des Immunogens, sowie des Impfvektors bei der Entwicklung Adenovirus-basierter Vakzinierungsstrategien für die Anwendung im Menschen.Immunization vectors based on an adenovirus type 5 (Ad5) backbone are valued for their high immunogenic potential, a characteristic which simultaneously limits their clinical use. Immunization studies in the murine Friend retrovirus (FV) model have shown that FV Leader-Gag protein delivered by Ad5 did not lead to induction of CD8+ T cell responses against the known immunodominant epitope, Leader-Gag-derived GagL85 93. In contrast, immunization with a DNA plasmid expressing Leader-Gag protein led to the induction of GagL85-93-specific CD8+ T cell responses. A second immunization study demonstrated that this induction of GagL85-93-specific CD8+ T cells was abrogated if the DNA plasmid encoding GagL85-93 also expressed the adenovirus epitopes Hexon486-494 and DBP418-426. These results suggested that adenoviral CD8+ T cell epitopes may have an inhibitory effect on the induction of transgene-specific CD8+ T cells, and it is this hypothesis which is explored in this thesis.
We were able to demonstrate that while the presence of H 2Db-restricted DBP418-426 did not have an effect on the induction of GagL85-93-specific CD8+ T cells, the GagL85 93(H-2Db) response was dominated by that of the H 2Dd-restricted Hexon486 494 epitope. However, no Hexon486-494-dependent suppression of GagL85 93-specific CD8+ T cells was observed in H2-Db/b mice, suggesting that competition is occurring on the level of the responding CD8+ T cells. Co-immunization with either IL2- or IL23-encoding DNA plasmids was able to partially restore induction of GagL85 93-specific CD8+ T cells in the presence of Hexon486 494. In contrast, neither co-immunization with IL2- or IL23-encoding Ad5 vectors, nor immunization of H2-Db/b mice with Ad5.Leader-Gag led to induction of GagL85-93-specific CD8+ T cell responses. This difference was attributed to the presence of other dominant Ad5-derived epitopes in the vector, which were verified by ELISpot assay. When less immunogenic OVA-derived epitopes Y3, Q4 and T4 were employed, enhanced induction of vector-specific CD8+ T cell responses following immunization was also observed.
In addition to interference by vector-induced immune responses, the efficacy of Ad5 vectors is greatly impaired by widespread pre-existing immunity against Ad5. This phenomenon can be observed by the complete lack of a GagL85 93-specific CD8+ T cell response to immunization with Ad5.TxnGagL in Ad5-pre-immune mice. However, increased binding antibody titers have also been reported in experiments using Ad5-pre-immune mice, contradicting the suggestion of vector neutralization and indicating possible ongoing transgene expression. Work presented here demonstrates that adoptive transfer of CD4+ or CD8+ T cells from Ad5-pre-immune mice showed no inhibitory effect on the induction of GagL85 93-specific CD8+ T cells, whereas GagL85 93-specific CD8+ T cell responses were abrogated after transfer of Ad5-pre-immune plasma. Adoptive transfer of Ad5-binding antibodies did not have a detectable effect on the induction of CD8+ T cells, therefore suggesting a role for Ad5-binding antibodies in enhancement of transgene-specific antibody titers in Ad5 pre-immune mice.
Based on phylogenetic differences between rare adenovirus types and Ad5 it is commonly assumed that vectors based on rare types are not subject to Ad5-specific immune responses. We therefore characterized and evaluated vectors based on adenovirus 48 and 50 and compared them to Ad5. Vectors based on both types were less immunogenic than Ad5 in most experiments and failed to induce transgene-specific CD8+ T cell responses. Only immunization with Ad48.Leader-GagC1K or Ad50.Env resulted in protective immune responses comparable to those induced by Ad5, which were dependent on the induction of CD4+T helper cells and humoral immune responses. Both, Ad48 and Ad50, induced vector-specific neutralizing antibodies which were cross-reactive against each other. Interestingly, vectors based on Ad48 were not influenced by pre-existing immunity against Ad5, whereas efficacy of Ad50-based vectors was impaired in Ad5-pre-immune mice to a similar extent as with Ad5 itself.
The work presented here further elucidates the influence of vector-induced immunity on vaccine responses, as well as the effect of pre-existing immunity against Ad5 on adenovirus-based immunization. These results highlight the importance of thorough immunogen and vector characterization during the development of vaccine regimens targeted for use in humans
Spectroscopic Study of Plasma in Microwave Source Designed for Hydrogen Production via Hydrocarbons Decomposition
No full textIn this paper, results of spectroscopic study of microwave (2.45 GHz) plasma at atmospheric pressure and high flow rate are presented. The plasma was generated by waveguide-supplied nozzleless cylindrical type microwave plasma source. Working gas flow rate and microwave absorbed power varied from 50 up to 150 l/min and from 1 up to 5.5 kW, respectively. The emission spectra in the range of 300-600 nm were recorded. The rotational and vibrational temperatures of molecules, as well as the rotational temperature of OH radicals were determined by comparing the measured and simulated spectra. The plasma gas temperature inferred from rotational temperature of heavy species ranged from 4000 to 6000 K. It depended on location in plasma, microwave absorbed power and working gas flow rate. The presented microwave plasma source can be used in various gas processing applications
Impingement heat transfer from turbulent air jets to flat plates: A literature survey
No full textHeat transfer characteristics of single and multiple turbulent air jets impinging on flat surfaces have been studied by many investigators. Results of many of these studies are summarized. Suggested correlations for use in the design of cooled turbine blades are noted, and areas where further research would be advisable are identified
Spectroscopic investigations of microwave microplasmas in various gases at atmospheric pressure
No full textIn this paper results of the experimental investigations of a coaxial
microwave (2.45 GHz) microplasma source (MMS) with graphite or tungsten
inner conductor operated in Ar, N2 and Ar/C2H2 mixture at
atmospheric pressure are presented. The microwave power absorbed by the
microplasmas and the intensity of UV-C emission from the microplasmas were
measured. Using optical emission spectroscopy, the electron number density
in Ar microplasma, and rotational and vibrational temperatures in N2
and Ar/C2H2 microplasmas were determined. All experiments were
performed with a gas flow rate from 0.3 to 8 l/min and absorbed microwave
power from 5 to 300 W. The simplicity of the MMS, stability of its operation
with atmospheric pressure gases, and parameters of the microplasmas allow
concluding that the MMS can be used in various applications
Infection of B Cell Follicle-Resident Cells by Friend Retrovirus Occurs during Acute Infection and Is Maintained during Viral Persistence
No full textABSTRACT B cell follicles of the spleen and lymph nodes are immune privileged sites and serve as sanctuaries for infected CD4+ cells in HIV infection. It is assumed that CD8+ T cell responses promote the establishment of the reservoir, as B cell follicles do not permit CD8+ T cell entry. Here we analyzed the infected cell population in the Friend retrovirus (FV) infection and investigated whether FV can similarly infect follicular cells. For analysis of FV-infected cells, we constructed a recombinant FV encoding the bright fluorescent protein mWasabi and performed flow cytometry with cells isolated from spleens, lymph nodes and bone marrow of FV-mWasabi-infected mice. Using t-stochastic neighbor embedding for data exploration, we demonstrate how the target cell population changes during the course of infection. While FV was widely distributed in erythrocytes, myeloid cells, B cells, and CD4+ T cells in the acute phase of infection, the bulk viral load in the late phase was carried by macrophages and follicular B and CD4+ T cells, suggesting that FV persists in cells that are protected from CD8+ T cell killing. Importantly, seeding into follicular cells was equally observed in CD8+ T cell-depleted mice and in highly FV-susceptible mice that mount a very weak immune response, demonstrating that infection of follicular cells is not driven by immune pressure. Our data demonstrate that infection of cells in the B cell follicle is a characteristic of the FV infection, making this murine retrovirus an even more valuable model for development of retrovirus immunotherapy approaches. IMPORTANCE Human immunodeficiency virus is notorious for its ability to avoid clearance by therapeutic interventions, which is partly attributed to the establishment of reservoirs in latently infected cells and cells that reside in immunologically privileged B cell follicles. In the work presented here, we show that cells of the B cell follicle are equally infected by a simple mouse gammaretrovirus. Using fluorescently labeled Friend retrovirus, we found that B cells and T cells in the B cell follicle, while not carrying the bulk of the virus load, were indeed infected by Friend virus in the early acute phase of the infection and persisted in the chronic infection. Our results suggest that infection of follicular cells may be a shared property of lymphotropic viruses and propose the FV infection of mice as a useful model to study strategies for follicular reservoir elimination
Hydrogen and Methane Production Under Conditions of Anaerobic Digestion of Key-Lime and Cabbage Wastes
No full textIn this article, the results of key lime fruit (Citrus aurantifolia) wastes and cabbage (Brassica L.) wastes anaerobic digestion are presented. Anaerobic digestion of the wastes was performed in batch process, neutral pH (key-lime 7.47 and cabbage 7.67) and substrate concentration of Volatile Suspended Solids (VSS) 10 gVSS/L. One of the aims of this research was to check the availability of these substrates to be the source of methane and hydrogen. Key lime wastes produced 32 times more methane than raw cabbage. However, hydrogen production from cabbage was 149 times higher than key lime. The percentage of methane production in cabbage was up to 81% and in key lime was up to 75%. This research showed from the substrates comparison that efficient hydrogen production is less dependent on low pKa, pH than on total solids of the substrates
