3,296 research outputs found
On hyperbolicity of SU(2)-equivariant, punctured disc bundles over the complex affine quadric
Given a holomorphic line bundle over the complex affine quadric , we
investigate its Stein, SU(2)-equivariant disc bundles. Up to equivariant
biholomorphism, these are all contained in a maximal one, say .
By removing the zero section to one obtains the unique Stein,
SU(2)-equivariant, punctured disc bundle over which contains entire
curves. All other such punctured disc bundles are shown to be Kobayashi
hyperbolic.Comment: 15 pages, v2: minor changes, to appear in Transformation Group
Polarised epithelial monolayers of the gastric mucosa reveal insights into mucosal homeostasis and defence against infection
Objective Helicobacter pylori causes life-long colonisation of the gastric mucosa, leading to chronic inflammation with increased risk of gastric cancer. Research on the pathogenesis of this infection would strongly benefit from an authentic human in vitro model. Design Antrum-derived gastric glands from surgery specimens served to establish polarised epithelial monolayers via a transient air–liquid interface culture stage to study cross-talk with H. pylori and the adjacent stroma. Results The resulting ‘mucosoid cultures’, so named because they recapitulate key characteristics of the gastric mucosa, represent normal stem cell-driven cultures that can be passaged for months. These highly polarised columnar epithelial layers encompass the various gastric antral cell types and secrete mucus at the apical surface. By default, they differentiate towards a foveolar, MUC5AC-producing phenotype, whereas Wnt signalling stimulates proliferation of MUC6-producing cells and preserves stemness—reminiscent of the gland base. Stromal cells from the lamina propria secrete Wnt inhibitors, antagonising stem-cell niche signalling and inducing differentiation. On infection with H. pylori, a strong inflammatory response is induced preferentially in the undifferentiated basal cell phenotype. Infection of cultures for several weeks produces foci of viable bacteria and a persistent inflammatory condition, while the secreted mucus establishes a barrier that only few bacteria manage to overcome. Conclusion Gastric mucosoid cultures faithfully reproduce the features of normal human gastric epithelium, enabling new approaches for investigating the interaction of H. pylori with the epithelial surface and the cross-talk with the basolateral stromal compartment. Our observations provide striking insights in the regulatory circuits of inflammation and defence.</p
A mission concept of Phobos/Deimos exploration
We have been designing the concept of Phobos/Deimos mission using the Japanese H-2 rocket as a first step in asteroid exploration. In planning the mission concept, we focused on development of methods to characterize the materials of Phobos/Deimos. The development of such methods will contribute to both scientific and resource explorations of asteroids. Here we report the preliminary concept of the mission
Cefotaxime for the detection of extended-spectrum β-lactamase or plasmid-mediated AmpC β-lactamase and clinical characteristics of cefotaxime-non-susceptible Escherichia coli and Klebsiella pneumoniae bacteraemia.
We investigated the performance of cefotaxime for the detection of extended-spectrum β-lactamase (ESBL) or plasmid-mediated AmpC β-lactamase (pAmpC) and the clinical characteristics of cefotaxime-non-susceptible Escherichia coli or Klebsiella pneumoniae (CTXNS-EK) bacteraemia. All of the consecutive bloodstream isolates between 2005 and 2010 in a Japanese university hospital were characterised using polymerase chain reaction (PCR). Risk factors and outcomes of CTXNS-EK were analysed by multivariate logistic regression analysis. We identified 58 CTXNS-EK (15.6%) from 249 E. coli and 122 K. pneumoniae. Cefotaxime with a minimum inhibitory concentration (MIC) of >1 μg/mL had a sensitivity of 98.3% and a specificity of 99.7% for the detection of ESBL or pAmpC. CTXNS-EK had increased from 4.5% in 2005 to 23% in 2009. Risk factors for CTXNS-EK were previous isolation of multidrug-resistant bacteria, use of oxyimino-cephalosporins or fluoroquinolones, and high Sequential Organ Failure Assessment (SOFA) score. Patients with CTXNS-EK bacteraemia less frequently received appropriate empirical therapy than patients with cefotaxime-susceptible EK bacteraemia (81% vs. 97%, p<0.001) and died within 30 days (21% vs. 5%, p=0.001). Using the current breakpoints of the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), cefotaxime alone can identify ESBL or pAmpC producers. CTXNS-EK is an important and increasingly prevalent bacteraemia pathogen
Development of geothermal field following the 2000 eruption of Usu volcano as revealed by ground temperature, resistivity and self-potential variations
The 2000 eruption of Usu volcano, NE Japan, took place on the foot of the somma, and formed a cryptodome
of 65 m high accompanying numerous faults. We made repeated measurements of ground temperature, Self-Potential
(SP) and electrical resistivity, in order to clarify the mechanism of development of the newly formed geothermal
field on the fault zone. Prior to the expansion of the geothermal field, we detected a resistive zone at
the center of the geothermal zone and it supposed to evidence that the zone involving dry steam phase had been
formed beneath the fault zone. A rapid expansion of the geothermal field followed along the fault zone away
from the craters. The place of maximum amplitude of the SP field also migrated following the expansion of the
high ground temperature zone. The high resistive part has shrunk as a consequence of the progress of condensation
to warm the surroundings. Based on the observations, we delineated the process of the hydrothermal circulation.
Considering the topographic effect of the SP field observed on the highly permeable zone in the Usu somma,
the potential flow along the slope of the soma was expected to play an important role to promote the rapid
expansion of the geothermal field and the migration of the most active part
Contribution of 3-D electrical resistivity tomography for landmines detection
Landmines are a type of inexpensive weapons
widely used in the pre-conflicted areas in many countries
worldwide. The two main types are the metallic and nonmetallic
(mostly plastic) landmines. They are most commonly
investigated by magnetic, ground penetrating radar
(GPR), and metal detector (MD) techniques. These geophysical
techniques however have significant limitations in
resolving the non-metallic landmines and wherever the host
materials are conductive. In this work, the 3-D electric resistivity
tomography (ERT) technique is evaluated as an alternative
and/or confirmation detection system for both landmine
types, which are buried in different soil conditions and
at different depths. This can be achieved using the capacitive
resistivity imaging system, which does not need direct
contact with the ground surface. Synthetic models for each
case have been introduced using metallic and non-metallic
bodies buried in wet and dry environments. The inversion
results using the L1 norm least-squares optimization method
tend to produce robust blocky models of the landmine body.
The dipole axial and the dipole equatorial arrays tend to have
the most favorable geometry by applying dynamic capacitive
electrode and they show significant signal strength for data
sets with up to 5% noise. Increasing the burial depth relative
to the electrode spacing as well as the noise percentage in the
resistivity data is crucial in resolving the landmines at different
environments. The landmine with dimension and burial
depth of one electrode separation unit is over estimated while
the spatial resolutions decrease as the burial depth and noise
percentage increase
Dendritic Cells in Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE) persists as a chronic inflammatory autoimmune disease and is characterized by the production of autoantibodies and immune complexes that affects multiple organs. The underlying mechanism that triggers and sustain disease are complex and involves certain susceptibility genes and environmental factors. There have been several immune mediators linked to SLE including cytokines and chemokines that have been reviewed elsewhere(1–3). A number of articles have reviewed the role of B cells and T cells in SLE(4–10). Here, we focus on role of dendritic cells (DC) and innate immune factors that may regulate autoreactive B cells
Effects of anisotropy in geostrophic turbulence
The Boussinesq model of convection in a flat layer with heating from below is
considered. We analyze the effects of anisotropy caused by rapid rotation in
physical and wave spaces and demonstrate the suppression of energy transfer by
rotation. We also examine the structure of the wave triangle in nonlinear
interaction. The range of parameters is adapted to the models of convection in
the geodynamo
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