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Search Results: 1 - 10 of 472605 matches for " William A Sosna "
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Design, assembly, and validation of a nose-only inhalation exposure system for studies of aerosolized viable influenza H5N1 virus in ferrets
Richard S Tuttle, William A Sosna, Deirdre E Daniels, Sara B Hamilton, John A Lednicky
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-135
Abstract: An aerosol generation and delivery system, referred to as a Nose-Only Bioaerosol Exposure System (NBIES), was assembled and function tested. The NBIES passed all safety tests, met expected engineering parameters, required relatively small quantities of material to obtain the desired aerosol concentrations of influenza virus, and delivered doses with high-efficacy. Ferrets withstood a mock exposure trial without signs of stress.The NBIES delivers doses of aerosolized influenza viruses with high efficacy, and uses less starting material than other similar designs. Influenza H5N1 and H3N2 viruses remain stable under the conditions used for aerosol generation and sample collection. The NBIES is qualified for studies of aerosolized H5N1 virus.Human infections caused by highly pathogenic avian influenza H5N1 viruses (H5N1) that arose from 2003-onwards have been rare (495 cases confirmed through April 21, 2010) but have a fatality rate of about 59% [1]. There is limited knowledge about the potential routes and determinants required for H5N1 transmission to and between humans. Human-to-human transmissions have rarely been reported, and have been limited, inefficient and un-sustained. In ferret transmission models, H5N1 are inconsistent in transmission by direct or indirect contact exposure, but direct intranasal exposure causes morbidity and sometimes, mortality (2, 3, and J. Lednicky, unpublished). In contrast, the 1918 pandemic influenza virus was easily transmissible human-to-human, and caused the deaths of between 20 - 40 million people worldwide for a lethality rate of 2.5%. Whereas the differences in transmissibility and lethality between the two viruses are not fully understood, performing well-controlled inhalation exposure studies of aerosolized viable H5N1 in appropriate animal models may improve our understanding of factors responsible for -the acquisition of H5N1 infections by humans and the virulence/lethality relative to route of transmission.Four modes are mo
Ferrets develop fatal influenza after inhaling small particle aerosols of highly pathogenic avian influenza virus A/Vietnam/1203/2004 (H5N1)
John A Lednicky, Sara B Hamilton, Richard S Tuttle, William A Sosna, Deirdre E Daniels, David E Swayne
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-231
Abstract: Ferrets were successfully infected through intranasal instillation or through inhalation of small particle aerosols with four different doses of Influenza virus A/Vietnam/1203/2004 (H5N1). The animals developed severe influenza encephalomyelitis following intranasal or inhalation exposure to 101, 102, 103, or 104 infectious virus particles per ferret.Aerosolized Influenza virus A/Vietnam/1203/2004 (H5N1) is highly infectious and lethal in ferrets. Clinical signs appeared earlier in animals infected through inhalation of aerosolized virus compared to those infected through intranasal instillation.Human infections caused by H5N1 highly pathogenic avian influenza viruses (H5N1) that arose from 2003-onwards have been rare as evident by only 500 cases confirmed through 5 July, 2010. However, H5N1 have a fatality rate of about 59% [1]. In ferret transmission models, the H5N1 viruses were inconsistent in transmission by direct or indirect contact exposure including respiratory droplets, but direct intranasal exposure caused morbidity and sometimes, mortality [2,3]. In contrast, the 1918 pandemic influenza virus was easily transmissible, especially human-to-human, and caused the deaths of between 20 - 40 million people worldwide for a lethality rate of 2.5%, and experimental studies demonstrated efficient transmission ferret-to-ferret by respiratory droplets [4]. The differences in transmissibility and lethality between the two viruses is not fully understood, but the use of aerosol challenge may improve our understanding of factors responsible for transmission and lethality of the H5N1 viruses.There is limited knowledge about the potential routes and determinants required for H5N1 influenza virus transmission to and between humans, and it is not clear whether humans can be infected through inhalation of aerosolized contemporary H5N1 virus particles. Receptor distribution in the human airway is proposed to restrict efficient inter-human transmission of H5N1 influenza virus
Gas-permeable ethylene bags for the small scale cultivation of highly pathogenic avian influenza H5N1 and other viruses in embryonated chicken eggs
Sara B Hamilton, Deirdre E Daniels, William A Sosna, Eric R Jeppesen, Julie M Owells, Micah D Halpern, Kimberly S McCurdy, Jonathan O Rayner, John A Lednicky
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-23
Abstract: Virus yields acceptable for many applications were attained when influenza-, alpha-, flavi-, canine distemper-, and mousepox viruses were propagated in ECE sealed within ethylene breather bags.For many small-scale applications, ethylene breather bags can be used to encase ECE inoculated with various viruses.Embryonated (embryonating) chicken eggs (ECE) have long been used for isolating or propagating influenza and other viruses and certain bacteria such as Rickettsia [1-5]. Alpha-, corona-, flavi-, paramyxo-, and poxviruses are among the non-influenza viruses sometimes grown in ECE. For small-scale work with pathogens that must be worked with in BSL3 facilities, inoculated ECE are sometimes housed in small egg incubators kept within a BSC [such a practice is not practical for medium-to-large diagnostic operations, wherein ECE are placed in incubators within a bioBubble (Ft. Collins, CO) or similar barrier and containment enclosure]. Since ECE are fragile, accidental egg breakage is possible. Furthermore, diagnostic specimens inoculated into ECE may contain contaminating flora that form enough gas to break the egg shell. We sought a simple method to contain spillage from a broken ECE inoculated with dangerous pathogens, and explored the feasibility of using ethylene breather bags for that purpose. Ethylene breather bags are permeable to oxygen and carbon dioxide but retain water, and are used in the aquarium industry to transport live fish. Chicken embryo survival was examined and the yield of various influenza and other viruses in bagged eggs was determined.No differences were detected in the survival of chicken embryos in bagged vs non-bagged 7 - 12 day old ECE after five days of incubation without rotation as performed for virus-inoculated ECE. Noteworthy, especially during summer months, up to 20% attrition (death of non-inoculated ECE) occurred with some batches, regardless of whether the ECE were bagged or not bagged. Since the ECE are checked and culled if dea
Stability conditions under change of base field
Pawel Sosna
Mathematics , 2010, DOI: 10.1002/mana.201000020
Abstract: We investigate the behaviour of Bridgeland stability conditions under change of base field with particular focus on the case of finite Galois extensions. In particular, we prove that for a variety X over a field K and a finite Galois extension L/K the stability manifold of X embeds as a closed submanifold into the stability manifold of the base change variety.
Fourier-Mukai partners of canonical covers of bielliptic and Enriques surfaces
Pawel Sosna
Mathematics , 2011, DOI: 10.4171/RSMUP/130-7
Abstract: We prove that the canonical cover of an Enriques surface does not admit non-trivial Fourier-Mukai partners. We also show that the canonical cover of a bielliptic surface has at most one non-isomorphic Fourier-Mukai partner. The first result is then applied to birational Hilbert schemes of points and the second to birational generalised Kummer varieties. An appendix establishes that there are no exceptional or spherical objects in the derived category of a bielliptic surface.
Linearisations of triangulated categories with respect to finite group actions
Pawel Sosna
Mathematics , 2011, DOI: 10.4310/MRL.2012.v19.n5.a4
Abstract: Given an action of a finite group on a triangulated category, we investigate under which conditions one can construct a linearised triangulated category using DG-enhancements. In particular, if the group is a finite group of automorphisms of a smooth projective variety and the category is the bounded derived category of coherent sheaves, then our construction produces the bounded derived category of coherent sheaves on the smooth quotient variety resp. stack. We also consider the action given by the tensor product with a torsion canonical bundle and the action of a finite group on the category generated by a spherical object.
Some remarks on phantom categories and motives
Pawel Sosna
Mathematics , 2015,
Abstract: A phantom category is an admissible subcategory with vanishing Grothendieck group of the bounded derived category of coherent sheaves on a smooth projective variety. The goal of this paper is to study the abstract situation when such a category appears and establish some results which provide evidence for the idea that these categories are invisible on the level of Chow motives.
Derived equivalent conjugate K3 surfaces
Pawel Sosna
Mathematics , 2009, DOI: 10.1112/blms/bdq065
Abstract: We show that there exist a complex projective K3 surface $X$ and an automorphism of the complex numbers $\sigma$ such that the conjugate K3 surface $X^\sigma$ is a non-isomorphic Fourier-Mukai partner of $X$.
Scalar extensions of triangulated categories
Pawel Sosna
Mathematics , 2011, DOI: 10.1007/s10485-012-9297-0
Abstract: Given a triangulated category over a field $K$ and a field extension $L/K$, we investigate how one can construct a triangulated category over $L$. Our approach produces the derived category of the base change scheme $X_L$ if the category one starts with is the bounded derived category of a smooth projective variety $X$ over $K$ and the field extension is finite and Galois. We also investigate how the dimension of a triangulated category behaves under scalar extensions.
Evaluation of several less known pear (Pyrus communis L.) cultivars in the climatic conditions of Lower Silesia
Ireneusz Sosna,Daria Kortylewska
Acta Agrobotanica , 2012, DOI: 10.5586/aa.2012.033
Abstract: The aim of this study was to evaluate flowering, yielding, fruit quality, and growth of several less known pear cultivars growing in the climatic conditions of Lower Silesia. The experiment was conducted in the years 2006–2010 in the Fruit Experimental Station located in Samotwór near Wroc aw. In spring 2006, trees of several less known pear cultivars were planted: 'Isolda', 'Hortensia', 'Fertilia Delbard Delwilmor', 'Wy nica', 'Nojabrskaja' ('Xenia '), 'Uta', 'David' on Caucasian pear (Pyrus caucasica Fed.), 'Bohemica' on quince S1 (Cydonia oblonga Mill.) as well as 'Morava' and 'Blanka' on both these rootstocks. The highest total yield in the years 2007–2010 was recorded for the 'Nojabrskaja' and 'Wy nica' cultivars. The 'Blanka' cultivar produced the largest fruit, while fruits of the 'Isolda' cultivar were significantly the smallest. The largest growth and cross-sectional area of the trunk were recorded for the trees of the 'Wy nica' cultivar, while the smallest were observed in the case of 'Morava', in which the thickness of the trunk was similar on both rootstocks. The 'Morava' cultivar grafted on quince S1 formed the smallest crowns. On the other hand, 'Isolda' and 'Hortensia' were among the cultivars that produced the largest crowns.
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