289 research outputs found
Role of methylotrophy during symbiosis between Methylobacterium nodulans and Crotalaria podocarpa
Some rare leguminous plants of the genus Crotalaria are specifically nodulated by the methylotrophic bacterium Methylobacterium nodulans. In this study, the expression and role of bacterial methylotrophy were investigated during symbiosis between M. nodulans, strain ORS 2060(T), and its host legume, Crotalaria podocarpa. Using lacZ fusion to the mxaF gene, we showed that the methylotroph genes are expressed in the root nodules, suggesting methylotrophic activity during symbiosis. In addition, loss of the bacterial methylotrophic function significantly affected plant development. Indeed, inoculation of M. nodulans nonmethylotroph mutants in C. podocarpa decreased the total root nodule number per plant up to 60%, decreased the whole-plant nitrogen fixation capacity up to 42%, and reduced the total dry plant biomass up to 46% compared with the wild-type strain. In contrast, inoculation of the legume C. podocarpa with nonmethylotrophic mutants complemented with functional mxa genes restored the symbiotic wild phenotype. These results demonstrate the key role of methylotrophy during symbiosis between M. nodulans and C. podocarpa
A Virtual CAD Model of the LHC
Integrating the large and complex LHC machine into the existing LEP tunnel is a major challenge. Space was not really a problem to fit the LEP machine into its tunnel, but LHC cryostats are much larger than the LEP quadrupoles and the external cryogenic line fills even more the tunnel. Space problems lead to small clearances. Possible conflicts, or at least the most penalising ones, between installed equipment or with transport, must be solved beforehand in order to avoid unacceptable delays and extra costs during the installation. Experience gained with LEP has already shown the help that Computer-Aided Engineering tools could provide for the integration. A virtual model of the LHC is presently prepared. The actual LEP tunnel, known with a quite good accuracy (centimetre level), has been modelled and all the elements of the machine constructed as 3D objects with the CAD system are positioned accurately on the basis of data generated from the theoretical definition. These layouts are used to generate the reference sections and to check the clearances. Examples of this powerful approach applied to engineering for accelerators are given
Insertion Magnets
Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary
Design Report. The Large Hadron Collider (LHC) is one of the largest scientific
instruments ever built. Since opening up a new energy frontier for exploration
in 2010, it has gathered a global user community of about 7,000 scientists
working in fundamental particle physics and the physics of hadronic matter at
extreme temperature and density. To sustain and extend its discovery potential,
the LHC will need a major upgrade in the 2020s. This will increase its
luminosity (rate of collisions) by a factor of five beyond the original design
value and the integrated luminosity (total collisions created) by a factor ten.
The LHC is already a highly complex and exquisitely optimised machine so this
upgrade must be carefully conceived and will require about ten years to
implement. The new configuration, known as High Luminosity LHC (HL-LHC), will
rely on a number of key innovations that push accelerator technology beyond its
present limits. Among these are cutting-edge 11-12 tesla superconducting
magnets, compact superconducting cavities for beam rotation with ultra-precise
phase control, new technology and physical processes for beam collimation and
300 metre-long high-power superconducting links with negligible energy
dissipation. The present document describes the technologies and components
that will be used to realise the project and is intended to serve as the basis
for the detailed engineering design of HL-LHC.Comment: 19 pages, Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC)
: Preliminary Design Repor
Arbuscular mycorrhizal fungi diversity in revegetated areas after bauxite mining.
Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophs that have a symbiotic evolutionary relationship with about 80% of all terrestrial plant species. The fungus mainly supplies water and nutrients to the plant and receives photoassimilates. The AMF diversity affects both the competition among species and floristic composition of an area. Fluctuations in the population of this group of microorganisms can cause fluctuations in plant populations above ground. In this work, the AMF community profile in areas with different ages of revegetation was evaluated by morphological identification of spores and denaturing gradient gel electrophoresis (DGGE) techniques. We found 12 AMF species and dominance of the species Glomus macrocarpum determined by spore density. Since the richness level observed in each plot was low and there was predominance of one species of AMF, it can be concluded that these areas still present a high degree of disturbance. It was possible to detect complex band profiles by DGGE analyses for the two plant species studied, Visnia latifolia and Cecropia hololeuca. No relationship between AMF diversity and revegetation time was observed in these areas
Serological proteome analysis reveals new specific biases in the IgM and IgG autoantibody repertoires in autoimmune polyendocrine syndrome type 1
Objective: Autoimmune polyendocrine syndrome type 1 (APS 1) is caused by mutations in the AIRE gene that induce intrathymic T-cell tolerance breakdown, which results in tissue-specific autoimmune diseases.
Design: To evaluate the effect of a well-defined T-cell repertoire impairment on humoral self-reactive fingerprints, comparative serum self-IgG and self-IgM reactivities were analyzed using both one- and two-dimensional western blotting approaches against a broad spectrum of peripheral tissue antigens. Methods: Autoantibody patterns of APS 1 patients were compared with those of subjects affected by other autoimmune endocrinopathies (OAE) and healthy controls.
Results: Using a Chi-square test, significant changes in the Ab repertoire were found when intergroup patterns were compared. A singular distortion of both serum self-IgG and self-IgM repertoires was noted in APS 1 patients. The molecular characterization of these antigenic targets was conducted using a proteomic approach. In this context, autoantibodies recognized more significantly either tissue-specific antigens, such as pancreatic amylase, pancreatic triacylglycerol lipase and pancreatic regenerating protein 1α, or widely distributed antigens, such as peroxiredoxin-2, heat shock cognate 71-kDa protein and aldose reductase. As expected, a well-defined self-reactive T-cell repertoire impairment, as described in APS 1 patients, affected the tissue-specific self-IgG repertoire. Interestingly, discriminant IgM reactivities targeting both tissue-specific and more widely expressed antigens were also specifically observed in APS 1 patients. Using recombinant targets, we observed that post translational modifications of these specific antigens impacted upon their recognition.
Conclusions: The data suggest that T-cell-dependent but also T-cell-independent mechanisms are involved in the dynamic evolution of autoimmunity in APS 1
Conceptual Design of the LHC Interaction Region Upgrade: Phase-I
The LHC is starting operation with beam. The primary goal of CERN and the LHC community is to ensure that the collider is operated efficiently and that it achieves nominal performance in the shortest term. Since several years the community has been discussing the directions for maximizing the physics reach of the LHC by upgrading the experiments, in particular ATLAS and CMS, the LHC machine and the CERN proton injector complex, in a phased approach. The first phase of the LHC interaction region upgrade was approved by Council in December 2007. This phase relies on the mature Nb-Ti superconducting magnet technology with the target of increasing the LHC luminosity to 2 to 3 10^34 cm^-2s^-1, while maximising the use of the existing infrastructure. In this report, we present the goals and the proposed conceptual solutions for the LHC IR Upgrade Phase-I which include the recommendations of the conceptual design review
Associations of Lifestyle Factors, Disease History and Awareness with Health-Related Quality of Life in a Thai Population
10.1371/journal.pone.0049921PLoS ONE711
Heat and moisture exchangers (HMEs) and heated humidifiers (HHs) in adult critically ill patients: a systematic review, meta-analysis and meta-regression of randomized controlled trials
The aims of this systematic review and meta-analysis of randomized controlled trials are to evaluate the effects of active heated humidifiers (HHs) and moisture exchangers (HMEs) in preventing artificial airway occlusion and pneumonia, and on mortality in adult critically ill patients. In addition, we planned to perform a meta-regression analysis to evaluate the relationship between the incidence of artificial airway occlusion, pneumonia and mortality and clinical features of adult critically ill patients
Rhizobial characterization in revegetated areas after bauxite mining.
Little is known regarding how the increased diversity of nitrogen-fixing bacteria contributesto the productivity and diversity of plants in complex communities. However, some authorshave shown that the presence of a diverse group of nodulating bacteria is required for dif-ferent plant species to coexist. A better understanding of the plant symbiotic organismdiversity role in natural ecosystems can be extremely useful to define recovery strategies ofenvironments that were degraded by human activities. This study used ARDRA, BOX-PCRfingerprinting and sequencing of the 16S rDNA gene to assess the diversity of root nodulenitrogen-fixing bacteria in former bauxite mining areas that were replanted in 1981, 1985,1993, 1998, 2004 and 2006 and in a native forest. Among the 12 isolates for which the 16SrDNA gene was partially sequenced, eight, three and one isolate(s) presented similarity withsequences of the genera Bradyrhizobium, Rhizobium and Mesorhizobium, respectively. The rich-ness, Shannon and evenness indices were the highest in the area that was replanted theearliest (1981) and the lowest in the area that was replanted most recently (2006)
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