130 research outputs found
Facility Location in Evolving Metrics
Understanding the dynamics of evolving social or infrastructure networks is a
challenge in applied areas such as epidemiology, viral marketing, or urban
planning. During the past decade, data has been collected on such networks but
has yet to be fully analyzed. We propose to use information on the dynamics of
the data to find stable partitions of the network into groups. For that
purpose, we introduce a time-dependent, dynamic version of the facility
location problem, that includes a switching cost when a client's assignment
changes from one facility to another. This might provide a better
representation of an evolving network, emphasizing the abrupt change of
relationships between subjects rather than the continuous evolution of the
underlying network. We show that in realistic examples this model yields indeed
better fitting solutions than optimizing every snapshot independently. We
present an -approximation algorithm and a matching hardness result,
where is the number of clients and the number of time steps. We also
give an other algorithms with approximation ratio for the variant
where one pays at each time step (leasing) for each open facility
MAPK and JAK/STAT pathways targeted by miR-23a and miR-23b in prostate cancer: computational and in vitro approaches
The long-lasting inadequacy of existing treatments for prostate cancer has led to increasing efforts for developing novel therapies for this disease. MicroRNAs (miRNAs) are believed to have considerable therapeutic potential due to their role in regulating gene expression and cellular pathways. Identifying miRNAs that efficiently target genes and pathways is a key step in using these molecules for therapeutic purposes. Moreover, computational methods have been devised to help identify candidate miRNAs for each gene/pathway. MAPK and JAK/STAT pathways are known to have essential roles in cell proliferation and neoplastic transformation in different cancers including prostate cancer. Herein, we tried to identify miRNAs that target these pathways in the context of prostate cancer as therapeutic molecules. Genes involved in these pathways were analyzed with various algorithms to identify potentially targeting miRNAs. miR-23a and miR-23b were then selected as the best potential candidates that target a higher number of genes in these pathways with greater predictive scores. We then analyzed the expression of candidate miRNAs in LNCAP and PC3 cell lines as well as prostate cancer clinical samples. miR-23a and miR-23b showed a significant downregulation in cell line and tissue samples, a finding which is consistent with overactivation of these pathways in prostate cancer. In addition, we overexpressed miR-23a and miR-23b in LNCAP and PC3 cell lines, and these two miRNAs decreased IL-6R expression which has a critical role in these pathways. These results suggest the probability of utilizing miR-23a and miR-23b as therapeutic targets for the treatment of prostate cancer. © 2015, International Society of Oncology and BioMarkers (ISOBM)
Cisplatin Induces Up-Regulation of KAI1, a Metastasis Suppressor Gene, in MCF-7 Breast Cancer Cell Line
Purpose: To investigate the effect of cisplatin on cell toxicity and metastasis through modulation of KAI1 gene expression.Methods: MCF-7cells were incubated with different concentrations of cisplatin for 24 h. RNA was extracted by trizol and cDNA synthesized. KAI1 and TBP were chosen as target and internal control genes, respectively. Specific primers were designed by primer express software, v.3.0. KAI1/TBP and gene expression ratio was calculated using the formula, 2 -ΔΔCt.Results: Cisplatin exerted a dose-dependent inhibitory effect on the viability of highly metastatic MCF-7 cells. KAI1/TBP gene expression ratios were 1.97 ± 0.19 (p < 0.05), 2.96 ± 0.55 (p < 0.05), 9.06 ± 0.27 (p < 0.001) and 12.38 ± 0.88 (p < 0.01) in 10, 20, 50 and 100 μM concentrations of cisplatin. Conclusion: These findings indicate that cisplatin can inhibit metastasis by up-regulating KAI1 gene in MCF-7cells.Keywords: Cisplatin; KAI1; Metastasis; Breast Cancer; Real-time PCR
Relativistic entanglement in single-particle quantum states using Non-Linear entanglement witnesses
In this study, the spin-momentum correlation of one massive spin-1/2 and
spin-1 particle states, which are made based on projection of a relativistic
spin operator into timelike direction is investigated. It is shown that by
using Non-Linear entanglement witnesses (NLEWs), the effect of Lorentz
transformation would decrease both the amount and the region of entanglement.Comment: 16 pages, 2 figures; to be published in Quantum Inf Process,
10.1007/s11128-011-0289-z (2011
Quantum discord evolution of three-qubit states under noisy channels
We investigated the dissipative dynamics of quantum discord for correlated
qubits under Markovian environments.
The basic idea in the present scheme is that quantum discord is more general,
and possibly more robust and fundamental, than entanglement. We provide three
initially correlated qubits in pure Greenberger-Horne-Zeilinger (GHZ) or W
state and analyse the time evolution of the quantum discord under various
dissipative channels such as:
Pauli channels , , and , as well as
depolarising channels. Surprisingly, we find that under the action of Pauli
channel , the quantum discord of GHZ state is not affected by
decoherence. For the remaining dissipative channels, the W state is more robust
than the GHZ state against decoherence. Moreover, we compare the dynamics of
entanglement with that of the quantum discord under the conditions in which
disentanglement occurs and show that quantum discord is more robust than
entanglement except for phase flip coupling of the three qubits system to the
environment.Comment: 17 pages, 4 figures, accepted for publication in EPJ
Correlation dynamics of three spin under a classical dephasing environment
By starting from the stochastic Hamiltonian of the three correlated spins and
modeling their frequency fluctuations as caused by dephasing noisy environments
described by Ornstein-Uhlenbeck processes, we study the dynamics of quantum
correlations, including entanglement and quantum discord. We prepared initially
our open system with Greenberger-Horne-Zeilinger or W state and present the
exact solutions for evolution dynamics of entanglement and quantum discord
between three spins under both Markovian and non-Markovian regime of this
classical noise. By comparison the dynamics of entanglement with that of
quantum discord we find that entanglement can be more robust than quantum
discord against this noise. It is shown that by considering non-Markovian
extensions the survival time of correlations prolong.Comment: 13 pages, 4 figure
Approximation Algorithms for 2-Stage Stochastic Optimization Problems
Abstract. Stochastic optimization is a leading approach to model optimization problems in which there is uncertainty in the input data, whether from measurement noise or an inability to know the future. In this survey, we outline some recent progress in the design of polynomialtime algorithms with performance guarantees on the quality of the solutions found for an important class of stochastic programming problems — 2-stage problems with recourse. In particular, we show that for a number of concrete problems, algorithmic approaches that have been applied for their deterministic analogues are also effective in this more challenging domain. More specifically, this work highlights the role of tools from linear programming, rounding techniques, primal-dual algorithms, and the role of randomization more generally.
Dynamics of multipartite quantum correlations under decoherence
Quantum discord is an optimal resource for the quantification of classical
and non-classical correlations as compared to other related measures. Geometric
measure of quantum discord is another measure of quantum correlations.
Recently, the geometric quantum discord for multipartite states has been
introduced by Jianwei Xu [arxiv:quant/ph.1205.0330]. Motivated from the recent
study [Ann. Phys. 327 (2012) 851] for the bipartite systems, I have
investigated global quantum discord (QD) and geometric quantum discord (GQD)
under the influence of external environments for different multipartite states.
Werner-GHZ type three-qubit and six-qubit states are considered in inertial and
non-inertial settings. The dynamics of QD and GQD is investigated under
amplitude damping, phase damping, depolarizing and flipping channels. It is
seen that the quantum discord vanishes for p>0.75 in case of three-qubit GHZ
states and for p>0.5 for six qubit GHZ states. This implies that multipartite
states are more fragile to decoherence for higher values of N. Surprisingly, a
rapid sudden death of discord occurs in case of phase flip channel. However,
for bit flip channel, no sudden death happens for the six-qubit states. On the
other hand, depolarizing channel heavily influences the QD and GQD as compared
to the amplitude damping channel. It means that the depolarizing channel has
the most destructive influence on the discords for multipartite states. From
the perspective of accelerated observers, it is seen that effect of environment
on QD and GQD is much stronger than that of the acceleration of non-inertial
frames. The degradation of QD and GQD happens due to Unruh effect. Furthermore,
QD exhibits more robustness than GQD when the multipartite systems are exposed
to environment.Comment: 15 pages, 4 figures, 4 table
Downregulation of miR-1266-5P, miR-185-5P and miR-30c-2 in prostatic cancer tissue and cell lines
Over the latest decade, the role of microRNAs (miRNAs/miRs) has received more attention. miRNAs are small non-coding RNAs that may serve a role as oncogenes or tumor suppressor genes. Certain miRNAs regulate the apoptosis pathway by influencing pro- or anti-apoptotic genes. We hypothesized that increases in the expression of B cell lymphoma 2 (BCL2) and BCL2-like 1 (BCL2L1) genes, which have been reported in various types of cancer tissues, may be due to the downregulation of certain miRNAs. The present study aimed to identify miRNAs that target BCL2 and BCL2L1 anti-apoptotic genes in prostate cancer (PCa) clinical tissue samples. Certain candidate miRNAs were selected bioinfor-matically and their expression in PCa samples was analyzed and compared with that in benign prostatic hyperplasia (BPH) tissue samples. The candidate miRNAs that targeted BCL2 and BCL2L1 genes were searched in online databases (miRWalk, microRNA.org, miRDB and TargetScan). A total of 12 miRNAs that target the 3'-untranslated region of the aforementioned genes and/or for which downregulation of their expression has previously been reported in cancer tissues. A total of 30 tumor tissue samples from patients with PCa and 30 samples tissues from patients with BPH were obtained and were subjected to reverse transcription-quantitative polymerase chain reaction for expression analysis of 12 candidate miRNAs, and the BCL2 and BCL2L1 genes. Additionally, expression of 3 finally selected miRNAs and genes was evaluated in prostate cancer PC3 and DU145 cell lines and human umbilical vein endothelial cells. Among 12 miRNA candidates, the expression of miR-1266, miR-185 and miR-30c-2 was markedly downregulated in PCa tumor tissues and cell lines. Furthermore, downregulation of these miRNAs was associated with upregulation of the BCL2 and BCL2L1 genes. An inverse association between three miRNAs (miR-1266, miR-185 and miR-30c-2) and two anti-apoptotic genes (BCL2 and BCL2L1) may be considered for interventional miRNA therapy of PCa. © 2018, Spandidos Publications. All rights reserved
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