2,085 research outputs found
Autophagy-deficient breast cancer shows early tumor recurrence and escape from dormancy
Breast cancer patients who initially respond to cancer therapies often succumb to distant recurrence of the disease. It is not clear why people with the same type of breast cancer respond to treatments differently; some escape from dormancy and relapse earlier than others. In addition, some tumor clones respond to immunotherapy while others do not. We investigated how autophagy plays a role in accelerating or delaying recurrence of neu-overexpressing mouse mammary carcinoma (MMC) following adriamycin (ADR) treatment, and in affecting response to immunotherapy. We explored two strategies: 1) transient blockade of autophagy with chloroquine (CQ), which blocks fusion of autophagosomes and lysosomes during ADR treatment, and 2) permanent inhibition of autophagy by a stable knockdown of ATG5 (ATG5KD), which inhibits the formation of autophagosomes in MMC during and after ADR treatment. We found that while CQ prolonged tumor dormancy, but that stable knockdown of autophagy resulted in early escape from dormancy and recurrence. Interestingly, ATG5KD MMC contained an increased frequency of ADR-induced polyploid-like cells and rendered MMC resistant to immunotherapy. On the other hand, a transient blockade of autophagy did not affect the sensitivity of MMC to immunotherapy. Our observations suggest that while chemotherapy-induced autophagy may facilitate tumor relapse, cell-intrinsic autophagy delays tumor relapse, in part, by inhibiting the formation of polyploid-like tumor dormancy
Evolution of Our Understanding of Myeloid Regulatory Cells: From MDSCs to Mregs
The term myeloid-derived suppressor cells (MDSCs) was first suggested in 2007 in order to reflect the origin and function of myeloid cells during immunosuppression in cancer and other pathologic conditions. Emerging evidence suggests that MDSCs suppress CTL and Th1 responses in malignant diseases while they regulate effective immune responses in parasitic and helminth infections as well as Th17 inflammatory response during autoimmune diseases. Based on these data, the term myeloid regulatory cells (Mregs) more accurately reflects their function and interactions with different cells of the immune system during diseased conditions. Here, we provide evidence on the multifaceted function of Mregs during diseased state
On the peak-to-average power of OFDM signals based on oversampling
Orthogonal frequency-division multiplexing (OFDM) introduces large amplitude variations in time, which can result in significant signal distortion in the presence of nonlinear amplifiers. We introduce a new bound for the peak of the continuous envelope of an OFDM signal, based on the maximum of its corresponding oversampled sequence; it is shown to be very tight as the oversampling rate increases. The bound is then used to derive a closed-form probability upper bound for the complementary cumulative distribution function of the peak-to-mean envelope power ratio of uncoded OFDM signals for sufficiently large numbers of subcarriers. As another application of the bound for oversampled sequences, we propose tight relative error bounds for computation of the peak power using two main methods: the oversampled inverse fast Fourier transform and the method introduced for coded systems based on minimum distance decoding of the code
Morphological instability of the solid-liquid interface in crystal growth under supercooled liquid film flow and natural convection airflow
Ring-like ripples on the surface of icicles are an example of morphological
instability of the ice-water interface during ice growth under supercooled
water film flow. The surface of icicles is typically covered with ripples of
about 1 cm in wavelength, and the wavelength appears to be almost independent
of external temperature, icicle radius, and volumetric water flow rate. One
side of the water layer consists of the water-air surface and growing ice is
the other. This is one of the more complicated moving phase boundary problems
with two interfaces. A recent theoretical work [K. Ueno, Phys. Rev. E 68,
(2003) 021603] to address the underlying instability that produces ripples is
based on the assumption of the absence of airflow around icicles. In this
paper, we extend the previous theoretical framework to include a natural
convection airflow ahead of the water-air surface and consider whether the
effect of natural convection airflow on the wavelength of ripples produced on
an ice surface is essential or not.Comment: 19 pages, 5 figure
Branch Flow Model: Relaxations and Convexification—Part II
We propose a branch flow model for the analysis and optimization of mesh as well as radial networks. The model leads to a new approach to solving optimal power flow (OPF) that consists of two relaxation steps. The first step eliminates the voltage and current angles and the second step approximates the resulting problem by a conic program that can be solved efficiently. For radial networks, we prove that both relaxation steps are always exact, provided there are no upper bounds on loads. For mesh networks, the conic relaxation is always exact but the angle relaxation may not be exact, and we provide a simple way to determine if a relaxed solution is globally optimal. We propose convexification of mesh networks using phase shifters so that OPF for the convexified network can always be solved efficiently for an optimal solution. We prove that convexification requires phase shifters only outside a spanning tree of the network and their placement depends only on network topology, not on power flows, generation, loads, or operating constraints. Part I introduces our branch flow model, explains the two relaxation steps, and proves the conditions for exact relaxation. Part II describes convexification of mesh networks, and presents simulation results
Linear stability analysis in inhomogeneous equilibrium configurations
We propose a novel method to find local plane-wave solutions of the
linearized equations of motion of relativistic hydrodynamics in inhomogeneous
equilibrium configurations, i.e., when a fluid in equilibrium is rigidly moving
with nonzero thermal vorticity. Our method is based on extending the conserved
currents to the tangent bundle, using a type of Wigner transformation. The
Wigner-transformed conserved currents can then be Fourier-transformed into the
cotangent bundle to obtain the dispersion relations for the space-time
dependent eigenfrequencies. We show that the connection between the stability
of hydrodynamics and the evolution of plane waves is not as straightforward as
in the homogeneous case, namely, it is restricted to the equilibrium-preserving
directions in the cotangent bundle. We apply this method to
Mueller-Israel-Stewart (MIS) theory and show that the interplay between the
bulk viscous pressure and the shear-stress tensor with acceleration and
rotation leads to novel modes, as well as modifications of the already known
ones. We conclude that, within the domain of applicability, i.e., when boundary
effects are negligible and the vorticity is not too large, MIS theory is stable
and causal, with the same stability and causality conditions as for homogeneous
equilibrium configurations.Comment: 29 pages, 2 figure
Branch Flow Model: Relaxations and Convexification (Parts I, II)
We propose a branch flow model for the anal- ysis and optimization of mesh as
well as radial networks. The model leads to a new approach to solving optimal
power flow (OPF) that consists of two relaxation steps. The first step
eliminates the voltage and current angles and the second step approximates the
resulting problem by a conic program that can be solved efficiently. For radial
networks, we prove that both relaxation steps are always exact, provided there
are no upper bounds on loads. For mesh networks, the conic relaxation is always
exact but the angle relaxation may not be exact, and we provide a simple way to
determine if a relaxed solution is globally optimal. We propose convexification
of mesh networks using phase shifters so that OPF for the convexified network
can always be solved efficiently for an optimal solution. We prove that
convexification requires phase shifters only outside a spanning tree of the
network and their placement depends only on network topology, not on power
flows, generation, loads, or operating constraints. Part I introduces our
branch flow model, explains the two relaxation steps, and proves the conditions
for exact relaxation. Part II describes convexification of mesh networks, and
presents simulation results.Comment: A preliminary and abridged version has appeared in IEEE CDC, December
201
New class of exact solutions to Einstein-Maxwell-dilaton theory on four-dimensional Bianchi type IX geometry
We construct new classes of cosmological solution to the five dimensional
Einstein-Maxwell-dilaton theory, that are non-stationary and almost conformally
regular everywhere. The base geometry for the solutions is the four-dimensional
Bianchi type IX geometry. In the theory, the dilaton field is coupled to the
electromagnetic field and the cosmological constant term, with two different
coupling constants. We consider all possible solutions with different values of
the coupling constants, where the cosmological constant takes any positive,
negative or zero values. In the ansatzes for the metric, dilaton and
electromagnetic fields, we consider dependence on time and two spatial
directions. We also consider a special case of the Bianchi type IX geometry, in
which the geometry reduces to that of Eguchi-Hanson type II geometry and find a
more general solution to the theory.Comment: 38 pages, 15 figures, two new appendices added, typos correcte
Decentralized P2P Trading based on Blockchain for Retail Electricity Markets
This paper introduces peer to peer (P2P) trading mechanisms based on
decentralized Blockchain to facilitate retail electricity market for
ever-increasing distributed energy resources (DERs). The Blockchain network
supports fast and secure retail trading among DERs and facilitates a
sustainable local P2P trading platform. In this decentralized Blockchain
architecture no single entity or organization has control over the entire
system rather all users collectively maintain control. The effectiveness of the
proposed automated market design and optimization is simulated using different
use case scenarios in an open source Blockchain Simulator and MATLAB. The
results show the efficacy of the trading mechanism in achieving demand response
through strategies such as peak load shaving, load shifting, and integration of
DERs
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