5,325 research outputs found
Intelectin contributes to allergen-induced IL-25, IL-33, and TSLP expression and type 2 response in asthma and atopic dermatitis.
The epithelial and epidermal innate cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) have pivotal roles in the initiation of allergic inflammation in asthma and atopic dermatitis (AD). However, the mechanism by which the expression of these innate cytokines is regulated remains unclear. Intelectin (ITLN) is expressed in airway epithelial cells and promotes allergic airway inflammation. We hypothesized that ITLN is required for allergen-induced IL-25, IL-33, and TSLP expression. In two asthma models, Itln knockdown reduced allergen-induced increases in Il-25, Il-33, and Tslp and development of type 2 response, eosinophilic inflammation, mucus overproduction, and airway hyperresponsiveness. Itln knockdown also inhibited house dust mite (HDM)-induced early upregulation of Il-25, Il-33, and Tslp in a model solely inducing airway sensitization. Using human airway epithelial cells, we demonstrated that HDM-induced increases in ITLN led to phosphorylation of epidermal growth factor receptor and extracellular-signal regulated kinase, which were required for induction of IL-25, IL-33, and TSLP expression. In two AD models, Itln knockdown suppressed expression of Il-33, Tslp, and Th2 cytokines and eosinophilic inflammation. In humans, ITLN1 expression was significantly increased in asthmatic airways and in lesional skin of AD. We conclude that ITLN contributes to allergen-induced Il-25, Il-33, and Tslp expression in asthma and AD
On the Goodness-of-Fit Tests for Some Continuous Time Processes
We present a review of several results concerning the construction of the
Cramer-von Mises and Kolmogorov-Smirnov type goodness-of-fit tests for
continuous time processes. As the models we take a stochastic differential
equation with small noise, ergodic diffusion process, Poisson process and
self-exciting point processes. For every model we propose the tests which
provide the asymptotic size and discuss the behaviour of the power
function under local alternatives. The results of numerical simulations of the
tests are presented.Comment: 22 pages, 2 figure
Self-assembly of Microcapsules via Colloidal Bond Hybridization and Anisotropy
Particles with directional interactions are promising building blocks for new
functional materials and may serve as models for biological structures.
Mutually attractive nanoparticles that are deformable due to flexible surface
groups, for example, may spontaneously order themselves into strings, sheets
and large vesicles. Furthermore, anisotropic colloids with attractive patches
can self-assemble into open lattices and colloidal equivalents of molecules and
micelles. However, model systems that combine mutual attraction, anisotropy,
and deformability have---to the best of our knowledge---not been realized.
Here, we synthesize colloidal particles that combine these three
characteristics and obtain self-assembled microcapsules. We propose that mutual
attraction and deformability induce directional interactions via colloidal bond
hybridization. Our particles contain both mutually attractive and repulsive
surface groups that are flexible. Analogous to the simplest chemical bond,
where two isotropic orbitals hybridize into the molecular orbital of H2, these
flexible groups redistribute upon binding. Via colloidal bond hybridization,
isotropic spheres self-assemble into planar monolayers, while anisotropic
snowman-like particles self-assemble into hollow monolayer microcapsules. A
modest change of the building blocks thus results in a significant leap in the
complexity of the self-assembled structures. In other words, these relatively
simple building blocks self-assemble into dramatically more complex structures
than similar particles that are isotropic or non-deformable
Cuts and flows of cell complexes
We study the vector spaces and integer lattices of cuts and flows associated
with an arbitrary finite CW complex, and their relationships to group
invariants including the critical group of a complex. Our results extend to
higher dimension the theory of cuts and flows in graphs, most notably the work
of Bacher, de la Harpe and Nagnibeda. We construct explicit bases for the cut
and flow spaces, interpret their coefficients topologically, and give
sufficient conditions for them to be integral bases of the cut and flow
lattices. Second, we determine the precise relationships between the
discriminant groups of the cut and flow lattices and the higher critical and
cocritical groups with error terms corresponding to torsion (co)homology. As an
application, we generalize a result of Kotani and Sunada to give bounds for the
complexity, girth, and connectivity of a complex in terms of Hermite's
constant.Comment: 30 pages. Final version, to appear in Journal of Algebraic
Combinatoric
Paracellular permeability is increased by basal lipopolysaccharide in a primary culture of colonic epithelial cells; an effect prevented by an activator of Toll-like receptor-2
Lipopolysaccharide (LPS), which generally activates Toll-like receptor 4 (TLR4), is expressed on commensal colonic bacteria. In a number of tissues, LPS can act directly on epithelial cells to increase paracellular permeability. Such an effect in the colon would have an important impact on the understanding of normal homeostasis and of pathology. Our aim was to use a novel primary culture of colonic epithelial cells grown on Transwells to investigate whether LPS, or Pam(3)CSK( 4), an activator of TLR2, affected paracellular permeability. Consequently, [(14)C]-mannitol transfer and transepithelial electrical resistance (TEER) were measured. The preparation consisted primarily of cytokeratin-18 positive epithelial cells that produced superoxide, stained for mucus with periodic acid-Schiff reagent, exhibited alkaline phosphatase activity and expressed TLR2 and TLR4. Tight junctions and desmosomes were visible by transmission electron microscopy. Basally, but not apically, applied LPS from Escherichia coli increased the permeability to mannitol and to a 10-kDa dextran, and reduced TEER. The LPS from Helicobacter pylori increased paracellular permeability of gastric cells when applied either apically or basally, in contrast to colon cells, where this LPS was active only from the basal aspect. A pan-caspase inhibitor prevented the increase in caspase activity caused by basal E. coli LPS, and reduced the effects of LPS on paracellular permeability. Synthetic Pam(3)CSK(4) in the basal compartment prevented all effects of basal E. coli LPS. In conclusion, LPS applied to the base of the colonic epithelial cells increased paracellular permeability by a mechanism involving caspase activation, suggesting a process by which perturbation of the gut barrier could be exacerbated. Moreover, activation of TLR2 ameliorated such effects
Overexpression of human kynurenine-3-monooxygenase protects against 3-hydroxykynurenine-mediated apoptosis through bidirectional non-linear feedback
Kynurenine 3-monooxygenase (KMO) is a critical regulator of inflammation. The preferred KMO substrate, kynurenine, is converted to 3-hydroxykynurenine (3HK), and this product exhibits cytotoxicity through mechanisms that culminate in apoptosis. Here, we report that overexpression of human KMO with orthotopic localisation to mitochondria creates a metabolic environment during which the cell exhibits increased tolerance for exogenous 3HK-mediated cellular injury. Using the selective KMO inhibitor Ro61-8048, we show that KMO enzyme function is essential for cellular protection. Pan-caspase inhibition with Z-VAD-FMK confirmed apoptosis as the mode of cell death. By defining expression of pathway components upstream and downstream of KMO, we observed alterations in other key kynurenine pathway components, particularly tryptophan-2,3-dioxygenase upregulation, through bidirectional nonlinear feedback. KMO overexpression also increased expression of inducible nitric oxide synthase (iNOS). These changes in gene expression are functionally relevant, because siRNA knockdown of the pathway components kynureninase and quinolinate phosphoribosyl transferase caused cells to revert to a state of susceptibility to 3HK-mediated apoptosis. In summary, KMO overexpression, and importantly KMO activity, have metabolic repercussions that fundamentally affect resistance to cell stress
Canalization of the evolutionary trajectory of the human influenza virus
Since its emergence in 1968, influenza A (H3N2) has evolved extensively in
genotype and antigenic phenotype. Antigenic evolution occurs in the context of
a two-dimensional 'antigenic map', while genetic evolution shows a
characteristic ladder-like genealogical tree. Here, we use a large-scale
individual-based model to show that evolution in a Euclidean antigenic space
provides a remarkable correspondence between model behavior and the
epidemiological, antigenic, genealogical and geographic patterns observed in
influenza virus. We find that evolution away from existing human immunity
results in rapid population turnover in the influenza virus and that this
population turnover occurs primarily along a single antigenic axis. Thus,
selective dynamics induce a canalized evolutionary trajectory, in which the
evolutionary fate of the influenza population is surprisingly repeatable and
hence, in theory, predictable.Comment: 29 pages, 5 figures, 10 supporting figure
Control of magnetic anisotropy by orbital hybridization in (La0.67Sr0.33MnO3)n/(SrTiO3)n superlattice
The asymmetry of chemical nature at the hetero-structural interface offers an
unique opportunity to design desirable electronic structure by controlling
charge transfer and orbital hybridization across the interface. However, the
control of hetero-interface remains a daunting task. Here, we report the
modulation of interfacial coupling of (La0.67Sr0.33MnO3)n/(SrTiO3)n
superlattices by manipulating the periodic thickness with n unit cells of
SrTiO3 and n unit cells La0.67Sr0.33MnO3. The easy axis of magnetic anisotropy
rotates from in-plane (n = 10) to out-of-plane (n = 2) orientation at 150 K.
Transmission electron microscopy reveals enlarged tetragonal ratio > 1 with
breaking of volume conservation around the (La0.67Sr0.33MnO3)n/(SrTiO3)n
interface, and electronic charge transfer from Mn to Ti 3d orbitals across the
interface. Orbital hybridization accompanying the charge transfer results in
preferred occupancy of 3d3z2-r2 orbital at the interface, which induces a
stronger electronic hopping integral along the out-of-plane direction and
corresponding out-of-plane magnetic easy axis for n = 2. We demonstrate that
interfacial orbital hybridization in superlattices of strongly correlated
oxides may be a promising approach to tailor electronic and magnetic properties
in device applications
Searching for Exoplanets Using a Microresonator Astrocomb
Detection of weak radial velocity shifts of host stars induced by orbiting
planets is an important technique for discovering and characterizing planets
beyond our solar system. Optical frequency combs enable calibration of stellar
radial velocity shifts at levels required for detection of Earth analogs. A new
chip-based device, the Kerr soliton microcomb, has properties ideal for
ubiquitous application outside the lab and even in future space-borne
instruments. Moreover, microcomb spectra are ideally suited for astronomical
spectrograph calibration and eliminate filtering steps required by conventional
mode-locked-laser frequency combs. Here, for the calibration of astronomical
spectrographs, we demonstrate an atomic/molecular line-referenced,
near-infrared soliton microcomb. Efforts to search for the known exoplanet HD
187123b were conducted at the Keck-II telescope as a first in-the-field
demonstration of microcombs
A Matrix Model for Baryons and Nuclear Forces
We propose a new matrix model describing multi-baryon systems. We derive the
action from open string theory on the wrapped baryon vertex D-branes embedded
in the D4-D8 model of large N holographic QCD. The positions of k baryons are
unified into k x k matrices, with spin/isospin of the baryons encoded in a set
of k-vectors. Holographic baryons are known to be very small in the large 't
Hooft coupling limit, and our model offers a better systematic approach to
dynamics of such baryons at short distances. We compute energetics and spectra
(k=1), and also short-distance nuclear force (k=2). In particular, we obtain a
new size of the holographic baryon and find a precise form of the repulsive
core of nucleons. This matrix model complements the instanton soliton picture
of holographic baryons, whose small size turned out to be well below the
natural length scale of the approximation involved there. Our results show
that, nevertheless, the basic properties of holographic baryons obtained there
are robust under stringy corrections within a few percents.Comment: 30 pages. v3: more comments added, published versio
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