1,179,042 research outputs found
Measles virus causes immunogenic cell death in human melanoma
Oncolytic viruses (OV) are promising treatments for cancer, with several currently undergoing testing in randomised clinical trials. Measles virus (MV) has not yet been tested in models of human melanoma. This study demonstrates the efficacy of MV against human melanoma. It is increasingly recognised that an essential component of therapy with OV is the recruitment of host anti-tumour immune responses, both innate and adaptive. MV-mediated melanoma cell death is an inflammatory process, causing the release of inflammatory cytokines including type-1 interferons and the potent danger signal HMGB1. Here, using human in vitro models, we demonstrate that MV enhances innate antitumour activity, and that MV-mediated melanoma cell death is capable of stimulating a melanoma-specific adaptive immune response
The colored Jones function is q-holonomic
A function of several variables is called holonomic if, roughly speaking, it
is determined from finitely many of its values via finitely many linear
recursion relations with polynomial coefficients. Zeilberger was the first to
notice that the abstract notion of holonomicity can be applied to verify, in a
systematic and computerized way, combinatorial identities among special
functions. Using a general state sum definition of the colored Jones function
of a link in 3-space, we prove from first principles that the colored Jones
function is a multisum of a q-proper-hypergeometric function, and thus it is
q-holonomic. We demonstrate our results by computer calculations.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol9/paper29.abs.htm
Determination of cellular strains by combined atomic force microscopy and finite element modeling
Many organs adapt to their mechanical environment as a result of physiological change or disease. Cells are both the detectors and effectors of this process. Though many studies have been performed in vitro to investigate the mechanisms of detection and adaptation to mechanical strains, the cellular strains remain unknown and results from different stimulation techniques cannot be compared. By combining experimental determination of cell profiles and elasticities by atomic force microscopy with finite element modeling and computational fluid dynamics, we report the cellular strain distributions exerted by common whole-cell straining techniques and from micromanipulation techniques, hence enabling their comparison. Using data from our own analyses and experiments performed by others, we examine the threshold of activation for different signal transduction processes and the strain components that they may detect. We show that modulating cell elasticity, by increasing the F-actin content of the cytoskeleton, or cellular Poisson ratio are good strategies to resist fluid shear or hydrostatic pressure. We report that stray fluid flow in some substrate-stretch systems elicits significant cellular strains. In conclusion, this technique shows promise in furthering our understanding of the interplay among mechanical forces, strain detection, gene expression, and cellular adaptation in physiology and disease
Circle homeomorphisms and shears
We give parameterizations of homeomorphisms, quasisymmetric maps and
symmetric maps of the unit circle in terms of shear coordinates for the Farey
tesselation.Comment: 26 pages, 3 figure
Using dissolved oxygen concentrations to determine mixed layer depths in the Bellingshausen Sea
Concentrations of oxygen (O<sub>2</sub>) and other dissolved gases in the oceanic mixed layer are often used to calculate air-sea gas exchange fluxes. The mixed layer depth (<i>z</i><sub>mix</sub>) may be defined using criteria based on temperature or density differences to a reference depth near the ocean surface. However, temperature criteria fail in regions with strong haloclines such as the Southern Ocean where heat, freshwater and momentum fluxes interact to establish mixed layers. Moreover, the time scales of air-sea exchange differ for gases and heat, so that <i>z</i><sub>mix</sub> defined using oxygen may be different than <i>z</i><sub>mix</sub> defined using temperature or density. Here, we propose to define an O<sub>2</sub>-based mixed layer depth, <i>z</i><sub>mix</sub>(O<sub>2</sub>), as the depth where the relative difference between the O<sub>2</sub> concentration and a reference value at a depth equivalent to 10 dbar equals 0.5 %. This definition was established by analysis of O<sub>2</sub> profiles from the Bellingshausen Sea (west of the Antarctic Peninsula) and corroborated by visual inspection. Comparisons of <i>z</i><sub>mix</sub>(O<sub>2</sub>) with <i>z</i><sub>mix</sub> based on potential temperature differences, i.e., <i>z</i><sub>mix</sub>(0.2 °C) and <i>z</i><sub>mix</sub>(0.5 °C), and potential density differences, i.e., <i>z</i><sub>mix</sub>(0.03 kg m<sup>&minus;3</sup>) and <i>z</i><sub>mix</sub>(0.125 kg m<sup>&minus;3</sup>), showed that <i>z</i><sub>mix</sub>(O<sub>2</sub>) closely follows <i>z</i><sub>mix</sub>(0.03 kg m<sup>&minus;3</sup>). Further comparisons with published <i>z</i><sub>mix</sub> climatologies and <i>z</i><sub>mix</sub> derived from World Ocean Atlas 2005 data were also performed. To establish <i>z</i><sub>mix</sub> for use with biological production estimates in the absence of O<sub>2</sub> profiles, we suggest using <i>z</i><sub>mix</sub>(0.03 kg m<sup>&minus;3</sup>), which is also the basis for the climatology by de Boyer Montégut et al. (2004)
Synthesis and characterisation of Fe<sub>6</sub> and Fe<sub>12</sub> clusters using bicine
Reaction of bicine {BicH3, N,N-bis(2-hydroxyethyl)glycine} with an Fe(III) oxo-centered pivalate triangle in MeCN in the presence of Et<sub>2</sub>NH yields [Et<sub>2</sub>NH<sub>2</sub>]<sub>2</sub>[Fe<sub>6</sub>O<sub>2</sub>(OH)<sub>2</sub>(Bic)<sub>2</sub>(O<sub>2</sub>CCMe<sub>3</sub>)<sub>8</sub>], which possesses an S = 5 ground state.
Changing the base to NaOMe produces [Fe<sub>12</sub>O<sub>4</sub>(Bic)<sub>4</sub>(HBic)<sub>4</sub>(O<sub>2</sub>CCMe<sub>3</sub>)<sub>8</sub>], which contains two Fe6 units bridged by the carboxylate arms from the bicine ligands. The complex displays strong antiferromagnetic coupling leading to an S = 0 ground state
Electrical and physical characterization of the Al<sub>2</sub>O<sub>3</sub>/ <i>p</i>-GaSb interface for 1%, 5%, 10%, and 22% (NH<sub>4</sub>)<sub>2</sub>S surface treatments
In this work, the impact of ammonium sulfide ((NH<sub>4</sub>)<sub>2</sub>S) surface treatment on the electrical passivation of the Al<sub>2</sub>O<sub>3</sub>/ <i>p</i>-GaSb interface is studied for varying sulfide concentrations. Prior to atomic layer deposition of Al<sub>2</sub>O<sub>3</sub>, GaSb surfaces were treated in 1%, 5%, 10%, and 22% (NH<sub>4</sub>)<sub>2</sub>S solutions for 10 min at 295 K. The smallest stretch-out and flatband voltage shifts coupled with the largest capacitance swing, as indicated by capacitance-voltage (<i>CV</i>) measurements, were obtained for the 1% treatment. The resulting interface defect trap density (<i>D</i><sub>it</sub>) distribution showed a minimum value of 4 x 10<sup>12</sup> cm<sup>-2</sup>eV<sup>-1</sup> at <i>E</i><sub>v</sub> + 0.27 eV. Transmission electron microscopy and atomic force microscopy examination revealed the formation of interfacial layers and increased roughness at the Al<sub>2</sub>O<sub>3</sub>/ <i>p</i>-GaSb interface of samples treated with 10% and 22% (NH<sub>4</sub>)<sub>2</sub>S. In combination, these effects degrade the interface quality as reflected in the <i>CV</i> characteristics
Floer homology and surface decompositions
Sutured Floer homology, denoted by SFH, is an invariant of balanced sutured
manifolds previously defined by the author. In this paper we give a formula
that shows how this invariant changes under surface decompositions. In
particular, if (M, \gamma)--> (M', \gamma') is a sutured manifold decomposition
then SFH(M',\gamma') is a direct summand of SFH(M, \gamma). To prove the
decomposition formula we give an algorithm that computes SFH(M,\gamma) from a
balanced diagram defining (M,\gamma) that generalizes the algorithm of Sarkar
and Wang.
As a corollary we obtain that if (M, \gamma) is taut then SFH(M,\gamma) is
non-zero. Other applications include simple proofs of a result of Ozsvath and
Szabo that link Floer homology detects the Thurston norm, and a theorem of Ni
that knot Floer homology detects fibred knots. Our proofs do not make use of
any contact geometry.
Moreover, using these methods we show that if K is a genus g knot in a
rational homology 3-sphere Y whose Alexander polynomial has leading coefficient
a_g non-zero and if the rank of \hat{HFK}(Y,K,g) < 4 then the knot complement
admits a depth < 2 taut foliation transversal to the boundary of N(K).Comment: 40 pages, 10 figures. Improved, expanded expositio
HREM studies of intergrowths in Sr2[Srn-1TinO3n+1] Ruddlesden-Popper phases synthesized by mechanochemical activation
A mechanochemical activation route has been applied in order to obtain the <i>n</i>=1–4 and ∞ members of the Sr<sub>2</sub>[Sr<sub>n</sub><sub>−1</sub>Ti<sub>n</sub>O<sub>3n+1</sub>] Ruddlesden–
Popper series from different (<i>n</i>+1)SrO:nTiO<sub>2</sub> mixtures. The mechanosynthesis of SrTiO<sub>3</sub> and Sr<sub>2</sub>TiO<sub>4</sub> was observed during the milling process
from the initial stoichiometric mixture, but in the cases of the <i>n</i>=2–4 members, a subsequent thermal treatment was needed. The synthesis
protocol of Sr<sub>3</sub>Ti<sub>2</sub>O<sub>7</sub> has been greatly improved and this compound can be isolated as a single, crystalline phase after annealing at 800°C. In the
case of Sr<sub>4</sub>Ti<sub>3</sub>O<sub>10</sub> and Sr<sub>5</sub>Ti<sub>4</sub>O<sub>13</sub>, the formation temperature was also decreased, but members with <i>n</i>=3 and 4 could not be isolated. Detailed
investigations using electron microscopy methods (TEM, HREM and SAED) were carried out in the samples corresponding to <i>n</i>=2–4. Although
a single ordered Sr<sub>3</sub>Ti<sub>2</sub>O<sub>7</sub> structure is dominant in the sample corresponding to <i>n</i>=2, a few intergrowths of other Ruddlesden–Popper phases were
observed. In the cases of <i>n</i>=3 and 4, the intergrowths of Ruddlesden–Popper phases are more frequent than in the <i>n</i>=2 composition and are
randomly distributed in the sample. The more frequent occurrence of such stacking faults, with increasing <i>n</i> value, leads to a somewhat disordered
layer stacking sequence
- …