2,808 research outputs found
IFNα and IFNÎł Impede Marekâs Disease Progression
Marekâs disease virus (MDV) is an alphaherpesvirus that causes Marekâs disease, a malignant lymphoproliferative disease of domestic chickens. While MDV vaccines protect animals from clinical disease, they do not provide sterilizing immunity and allow field strains to circulate and evolve in vaccinated flocks. Therefore, there is a need for improved vaccines and for a better understanding of innate and adaptive immune responses against MDV infections. Interferons (IFNs) play important roles in the innate immune defenses against viruses and induce upregulation of a cellular antiviral state. In this report, we quantified the potent antiviral effect of IFNα and IFNÎł against MDV infections in vitro. Moreover, we demonstrate that both cytokines can delay Marekâs disease onset and progression in vivo. Additionally, blocking of endogenous IFNα using a specific monoclonal antibody, in turn, accelerated disease. In summary, our data reveal the effects of IFNα and IFNÎł on MDV infection and improve our understanding of innate immune responses against this oncogenic virus
The Mega-City-Region of Munich: A Kingdom of Its Own Or a Space of Inter-Connected Flows?
In a world of continuing globalization mega-city regions (MCR) are of increasing importance. MCR are defined by a high concentration of regulation, innovation and gateway functions. Planners and politicians alike recognise that competition on this new spatial scale is becoming a strategic tool to develop the whole country. So they are looking for spatial strategies to ensure economic success and sustainable development (social and spatial cohesion) at the same time. However, only little is known about the factors, which constitute MCRs, the inter-relationships within and between MCR, the primacy of individual functional urban areas within MCR and the potential methods to communicate these complex structures to politicians and stakeholders. The paper will deal with the following questions that will be tested with a case-study in the Munich metropolitan region, the so-called Greater Munich Area: (1) Which flows and inter-relationsships of knowledge based economic activities define the MCR? How is the MCR itself embedded in the global network of mega-city regions? (2) What spatial mismatch becomes recognisable when differentiating between functional and morphological polycentricity? (3) What functional polycentricity do firms in the Advanced Producer Services and in the High-Tech sectors produce when looking at their office location strategies? (4)What policy recommendations follow for sustainable spatial development? Our hypothesis is that the current perception of MCRs by local and regional stakeholders is quite inhomogeneous. There is an obvious gap between the functional logic of the competitive world and the territorial logic of the planning administrations. So we propose to look at the individual logics and the spatial reach of the stakeholdersâ activites. The study will use an empirical survey for the Greater Munich Area that is mainly based on commuter data, location data of firms, business communication data and interviews with firms and a selection of key stakeholders.
The endothelial glycocalyx prefers albumin for evoking shear stress-induced, nitric oxide-mediated coronary dilatation
Background: Shear stress induces coronary dilatation via production of nitric oxide ( NO). This should involve the endothelial glycocalyx ( EG). A greater effect was expected of albumin versus hydroxyethyl starch ( HES) perfusion, because albumin seals coronary leaks more effectively than HES in an EG-dependent way. Methods: Isolated hearts ( guinea pigs) were perfused at constant pressure with Krebs-Henseleit buffer augmented with 1/3 volume 5% human albumin or 6% HES ( 200/0.5 or 450/0.7). Coronary flow was also determined after EG digestion ( heparinase) and with nitro-L-arginine ( NO-L-Ag). Results: Coronary flow ( 9.50 +/- 1.09, 5.10 +/- 0.49, 4.87 +/- 1.19 and 4.15 +/- 0.09 ml/ min/ g for `albumin', `HES 200', `HES 450' and `control', respectively, n = 5-6) did not correlate with perfusate viscosity ( 0.83, 1.02, 1.24 and 0.77 cP, respectively). NO-L-Ag and heparinase diminished dilatation by albumin, but not additively. Alone NO-L-Ag suppressed coronary flow during infusion of HES 450. Electron microscopy revealed a coronary EG of 300 nm, reduced to 20 nm after heparinase. Cultured endothelial cells possessed an EG of 20 nm to begin with. Conclusions: Albumin induces greater endothelial shear stress than HES, despite lower viscosity, provided the EG contains negative groups. HES 450 causes some NO-mediated dilatation via even a rudimentary EG. Cultured endothelial cells express only a rudimentary glycocalyx, limiting their usefulness as a model system. Copyright (c) 2007 S. Karger AG, Basel
Towards urban un-sustainability in Europe? An indicator-based analysis
In this article we analyse the relationship between urban land use development and population density in fifteen European urban areas. In the last 20 years the extent of built-up areas in Europe has increased by 20%, exceeding clearly the 6% rate of population growth over the same period. This is one of the consequences of unsustainable development patterns in large areas of Europe. In order to illustrate such unsustainable process we show five sets of indicators on built-up areas, residential land use, land taken by urban expansion, population density and how the population takes up the built-up space.The results show that analysing urban land use development necessitates the use of complementary indicators. The built-up areas have grown considerably in a sample of 15 European cities. The most rapid growth dates back to 1950s and 1960s. The annual growth pace has slowed down in the 1990s to 0.75 %. In half of the studied cities over 90% of all new housing areas built after the mid-1950s are discontinuous urban developments. This trend is increasing the use of private car and fragmentation of natural areas among others negative effects. When putting these findings into the context of stable or decreasing urban population, it is clear that the structure of most of European cities has become less compact, which demonstrates a de-centralisation process of urban land uses. We close by discussing on one hand the common urban land use and population density trends and on the other hand differences between the studied cities. Although most studied urban areas have experienced dispersed growth, as a result of the analysis we divide the cities in three groups: - compact cities,- cities with looser structures and lower densities,- and cities in the midway between the extremes.
The Transcriptional Landscape of Marekâs Disease Virus in Primary Chicken B Cells Reveals Novel Splice Variants and Genes
Marekâs disease virus (MDV) is an oncogenic alphaherpesvirus that infects chickens and poses a serious threat to poultry health. In infected animals, MDV efficiently replicates in B cells in various lymphoid organs. Despite many years of research, the viral transcriptome in primary target cells of MDV remained unknown. In this study, we uncovered the transcriptional landscape of the very virulent RB1B strain and the attenuated CVI988/Rispens vaccine strain in primary chicken B cells using high-throughput RNA-sequencing. Our data confirmed the expression of known genes, but also identified a novel spliced MDV gene in the unique short region of the genome. Furthermore, de novo transcriptome assembly revealed extensive splicing of viral genes resulting in coding and non-coding RNA transcripts. A novel splicing isoform of MDV UL15 could also be confirmed by mass spectrometry and RT-PCR. In addition, we could demonstrate that the associated transcriptional motifs are highly conserved and closely resembled those of the host transcriptional machinery. Taken together, our data allow a comprehensive re-annotation of the MDV genome with novel genes and splice variants that could be targeted in further research on MDV replication and tumorigenesis
Semi-supervised cross-entropy clustering with information bottleneck constraint
In this paper, we propose a semi-supervised clustering method, CEC-IB, that
models data with a set of Gaussian distributions and that retrieves clusters
based on a partial labeling provided by the user (partition-level side
information). By combining the ideas from cross-entropy clustering (CEC) with
those from the information bottleneck method (IB), our method trades between
three conflicting goals: the accuracy with which the data set is modeled, the
simplicity of the model, and the consistency of the clustering with side
information. Experiments demonstrate that CEC-IB has a performance comparable
to Gaussian mixture models (GMM) in a classical semi-supervised scenario, but
is faster, more robust to noisy labels, automatically determines the optimal
number of clusters, and performs well when not all classes are present in the
side information. Moreover, in contrast to other semi-supervised models, it can
be successfully applied in discovering natural subgroups if the partition-level
side information is derived from the top levels of a hierarchical clustering
The spatial implications of the functional proximity deriving from air passenger flows between European metropolitan urban regions
Until recently the traditional spatial configuration
of the European geography was based upon
the core-periphery model. The âpentagonâ, broadly
defined as lying between London, Paris, Milan,
Munich and Hamburg, was seen as the core area
characterised by having the highest concentration of
economic development in the European Union (EU),
with the remainder of the European territory viewed as
peripheral, albeit to varying degrees. In a number of
cases such peripheral areas equated with clear regional
disparities. The elaboration of the European Spatial
Development Perspective (ESDP) (CEC, European
spatial development perspective, towards balanced and
sustainable development in the territory of the European
Union, 1999) challenged this core-periphery
model. European spatial planning policies, aimed at
encouraging social and economic, and with ever
increasing importance, territorial cohesion, seek
amongst other aspects to encourage the development
of a balanced and polycentric urban system. This paper
adopts a network analysis approach to the analysis of
air passenger flows between some 28 principal European
metropolitan urban regions. The evaluation of
these flows contributes to an enhanced comprehension
of the spatial dynamics of the European metropolitan
territory which goes beyond that deriving from the
more standard analyses of the individual components
of the urban system. Several indicators are used,
deriving from gravitational modelling techniques, to
analyse the complexity of the air passenger flows. A
multidimensional scaling (MDS) technique is introduced
in order to interpret and visualise the resulting
spatial configuration and positioning of the different
metropolitan centres within the conceptual European
âspace of air passenger flowsâ, thereby contrasting with
the more traditional map-based geographical image of
Europe, based upon Cartesian coordinates.Peer Reviewe
Biogas upgrading by chemical absorption using ammonia rich absorbents derived from wastewater
The use of ammonia (NH3) rich wastewaters as an ecological chemical absorption solvent for the selective extraction of carbon dioxide (CO2) during biogas upgrading to âbiomethaneâ has been studied. Aqueous ammonia absorbents of up to 10,000 gNH3 mâ3 demonstrated CO2 absorption rates higher than recorded in the literature for packed columns using 20,000â80,000 g NH3 mâ3 which can be ascribed to the process intensification provided by the hollow fibre membrane contactor used in this study to support absorption. Centrifuge return liquors (2325 g mâ3 ionised ammonium, NH4+) and a regenerant (477 gNH4+ mâ3) produced from a cationic ion exchanger used to harvest NH4+ from crude wastewater were also tested. Carbon dioxide fluxes measured for both wastewaters compared reasonably with analogue ammonia absorption solvents of equivalent NH3 concentration. Importantly, this demonstrates that ammonia rich wastewaters can facilitate chemically enhanced CO2 separation which eliminates the need for costly exogenic chemicals or complex chemical handling which are critical barriers to implementation of chemical absorption. When testing NH3 analogues, the potential to recover the reaction product ammonium bicarbonate (NH4HCO3) in crystalline form was also illustrated. This is significant as it suggests a new pathway for ammonia separation which avoids biological nitrification and produces ammonia stabilised into a commercially viable fertiliser (NH4HCO3). However, in real ammonia rich wastewaters, sodium bicarbonate and calcium carbonate were preferentially formed over NH4HCO3 although it is proposed that NH4HCO3 can be preferentially formed by manipulating both ion exchange and absorbent chemistry
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