45,669 research outputs found
Supernatants derived from chemotherapy-treated cancer cell lines can modify angiogenesis
BACKGROUND: There is evidence that tumours produce substances such as cytokines and microvesicular bodies bearing bioactive molecules, which support the carcinogenic process. Furthermore, chemotherapy has also been shown to modify these exudates and in doing so, neutralise their tumourigenic influence. METHODS: In the current study, we have investigated the effect of chemotherapy agents on modifying the cytokine profile and microvesicular cargo of supernatants derived from cancer cell lines. In addition, we have explored the effect of these tumour-derived supernatants on angiogenesis, and how chemotherapy can alter the supernatants rendering them less pro-angiogenic. RESULTS: Herein, we show that supernatants contain a rich cocktail of cytokines, a number of which are potent modulators of angiogenesis. They also contain microvesicular bodies containing RNA transcripts that code for proteins involved in transcription, immune modulation and angiogenesis. These supernatants altered intracellular signalling molecules in endothelial cells and significantly enhanced their tubulogenic character; however, this was severely compromised when supernatants from tumours treated with chemotherapy was used instead. CONCLUSION: This study suggests tumour exudates and bioactive material from tumours can influence cellular functions, and that treatment with some chemotherapy can serve to negate these pro-tumourigenic processes
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Evidence of convection as a major source of condensation nuclei in the northern midlatitude upper troposphere
Defect formation beyond kibble-zurek mechanism and holography
We study the dynamic after a smooth quench across a continuous transition
from the disordered phase to the ordered phase. Based on scaling ideas, linear
response and the spectrum of unstable modes, we develop a theoretical
framework, valid for any second order phase transition, for the early-time
evolution of the condensate in the broken phase. Our analysis unveils a novel
period of non-adiabatic evolution after the system passes through the phase
transition, where a parametrically large amount of coarsening occurs before a
well-defined condensate forms. Our formalism predicts a rate of defect
formation parametrically smaller than the Kibble-Zurek prediction and yields a
criterion for the break-down of Kibble-Zurek scaling for sufficiently fast
quenches. We numerically test our formalism for a thermal quench in a 2 + 1
dimensional holographic superfluid. These findings, of direct relevance in a
broad range of fields including cold atom, condensed matter, statistical
mechanism and cosmology, are an important step towards a more quantitative
understanding of dynamical phase transitions.We thank Laurence Yaffe for useful discussions. The work of P. M. C. is supported by the Fundamental Laws Initiative of the Center for the Fundamental Laws of Nature at Harvard University. The work of H. L. is partially supported by the U.S. Department of Energy (DOE) under Cooperative Research Agreement No. DE-FG0205ER41360. A. M. G.-G. was supported by Engineering and Physical Sciences Research Council, Grant No. EP/I004637/1; Fundação para a Ciência e a Tecnologia, Grant No. PTDC/FIS/111348/2009; and a Marie Curie International Reintegration Grant No. PIRG07-GA-2010-268172.This is the final version of the article. It first appeared from APS via http://dx.doi.org/10.1103/PhysRevX.5.02101
Real estate investments and financial stability : evidence from regional commercial banks in China
The 2008 United States subprime mortgage crisis demonstrated how developments in
real estate markets can cause instability in the banking sector and raised concerns in
many emerging economies with significant real estate development and a rapidly
growing commercial banking sector, particularly in China. There is clear evidence
that commercial banks in China, especially regional commercial banks, have lent
significantly to the real estate sector. The recent slowdown in the housing market in
China and the increase in nonperforming loans (NPLs) in China's commercial banking
sector motivated us to investigate the connection between real estate markets and
banking stability. This paper proposes three testable hypotheses linking the growth of
investment in real estate and the stability of regional commercial banks in China,
measured by NPLs. Our empirical results reveal a close connection between the
growth of investment in real estate and the NPLs among regional commercial banks,
and its sensitivity to real estate market cycles. When real estate market activity
declines, our results suggest, regional commercial banks can find themselves in
trouble if they have significant exposure to one type of (real estate) asset. In addition,
we find that regional bank competition plays a critical role in defining the relationship
between bank stability and real estate investment activity
Stereo Computation for a Single Mixture Image
This paper proposes an original problem of \emph{stereo computation from a
single mixture image}-- a challenging problem that had not been researched
before. The goal is to separate (\ie, unmix) a single mixture image into two
constitute image layers, such that the two layers form a left-right stereo
image pair, from which a valid disparity map can be recovered. This is a
severely illposed problem, from one input image one effectively aims to recover
three (\ie, left image, right image and a disparity map). In this work we give
a novel deep-learning based solution, by jointly solving the two subtasks of
image layer separation as well as stereo matching. Training our deep net is a
simple task, as it does not need to have disparity maps. Extensive experiments
demonstrate the efficacy of our method.Comment: Accepted by European Conference on Computer Vision (ECCV) 201
Partial Homology Relations - Satisfiability in terms of Di-Cographs
Directed cographs (di-cographs) play a crucial role in the reconstruction of
evolutionary histories of genes based on homology relations which are binary
relations between genes. A variety of methods based on pairwise sequence
comparisons can be used to infer such homology relations (e.g.\ orthology,
paralogy, xenology). They are \emph{satisfiable} if the relations can be
explained by an event-labeled gene tree, i.e., they can simultaneously co-exist
in an evolutionary history of the underlying genes. Every gene tree is
equivalently interpreted as a so-called cotree that entirely encodes the
structure of a di-cograph. Thus, satisfiable homology relations must
necessarily form a di-cograph. The inferred homology relations might not cover
each pair of genes and thus, provide only partial knowledge on the full set of
homology relations. Moreover, for particular pairs of genes, it might be known
with a high degree of certainty that they are not orthologs (resp.\ paralogs,
xenologs) which yields forbidden pairs of genes. Motivated by this observation,
we characterize (partial) satisfiable homology relations with or without
forbidden gene pairs, provide a quadratic-time algorithm for their recognition
and for the computation of a cotree that explains the given relations
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Impact of aircraft emissions on reactive nitrogen over the North Atlantic Flight Corridor region
Interactions in vivo between the Vif protein of HIV-1 and the precursor (Pr55GAG) of the virion nucleocapsid proteins
The abnormality of viral core structure seen in vif-defective HIV-1 grown in PBMCs has suggested a role for Vif in viral morphogenesis. Using an in vivo mammalian two-hybrid assay, the interaction between Vif and the precursor (Pr55GAG) of the virion nucleocapsid proteins has been analysed. This revealed the amino-terminal (aa 1–22) and central (aa 70–100) regions of Vif to be essential for its interaction with Pr55GAG, but deletion of the carboxy-terminal (aa 158–192) region of the protein had only a minor effect on its interaction. Initial deletion studies carried out on Pr55GAG showed that a 35-amino-acid region of the protein bridging the MA(p17)–CA(p24) junction was essential for its ability to interact with Vif. Site-directed mutagenesis of a conserved tryptophan (Trp21) near the amino terminus of Vif showed it to be important for the interaction with Pr55GAG. By contrast, mutagenesis of the highly conserved YLAL residues forming part of the BC-box motif, shown to be important in Vif promoting degradation of APOBEC3G/3F, had little or no effect on the Vif–Pr55GAG interaction
Collisions of low-energy antiprotons with molecular hydrogen: ionization, excitation and stopping power
A time-dependent coupled-channel approach was used to calculate ionization,
excitation, and energy-loss cross sections as well as energy spectra for
antiproton and proton collisions with molecular hydrogen for impact energies 8
keV < E < 4000 keV.Comment: 4 pages, 4 figures, conference LEAP0
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