96 research outputs found
Tradable credit scheme for rush hour travel choice with heterogeneous commuters
This article proposes a tradable credit scheme for managing commuters travel choices. The scheme considers bottleneck congestion and modal split in a competitive highway-transit network with heterogeneous commuters who are distinguished by their valuation of travel time. The scheme charges all auto travelers who pass the bottleneck during a peak-time window in the form of mobility credits. Those who avoid the peak-time window, by either traveling outside the peak-time window or switching to the transit mode, may be rewarded credits. An artificial market is created so that the travelers may trade these credits with each other. We formulate the credit price and the rewarded and charged credits under tradable credit scheme. Our analyses indicate that the optimal tradable credit scheme can achieve nearly 40% efficiency gains depending on the level of commuters heterogeneity. In addition, this scheme distributes the benefits among all the commuters directly through the credit trading. Our results suggest that in assessing the efficiency of tradable credit scheme, it is important to take into account the commuters heterogeneity. Numerical experiments are conducted to examine the sensitivity of tradable credit scheme designs to various system parameters
Coherent Population Trapping of an Electron Spin in a Single Negatively Charged Quantum Dot
Coherent population trapping (CPT) refers to the steady-state trapping of
population in a coherent superposition of two ground states which are coupled
by coherent optical fields to an intermediate state in a three-level atomic
system. Recently, CPT has been observed in an ensemble of donor bound spins in
GaAs and in single nitrogen vacancy centers in diamond by using a fluorescence
technique. Here we report the demonstration of CPT of an electron spin in a
single quantum dot (QD) charged with one electron.Comment: to be appeared in Nature Physic
The role of versican isoforms V0/V1 in glioma migration mediated by transforming growth factor-β2
Versican is a large chondroitin sulphate proteoglycan produced by several tumour cell types, including high-grade glioma. The increased expression of certain versican isoforms in the extracellular matrix (ECM) plays a role in tumour cell growth, adhesion and migration. Transforming growth factor-β2 (TGF-β2) is an important modulator of glioma invasion, partially by remodeling the ECM. However, it is unknown whether it interacts with versican during malignant progression of glioma cells. Here, we analysed the effect of TGF-β2 on the expression of versican isoforms. The expression of versican V0/V1 was upregulated by TGF-β2 detected by quantitative polymerase chain reaction and immunoprecipitation, whereas V2 was not induced. Using time-lapse scratch and spheroid migration assays, we observed that the glioma migration rate is significantly increased by exogenous TGF-β2 and inhibited by TGF-β2-specific antisense oligonucleotides. Interestingly, an antibody specific for the DPEAAE region of glycosaminoglycan-β domain of versican was able to reverse the effect of TGF-β2 on glioma migration in a dose-dependent manner. Taken together, we report here that TGF-β2 triggers the malignant phenotype of high-grade gliomas by induction of migration, and that this effect is, at least in part, mediated by versican V0/V1
An Integrated Qualitative and Quantitative Biochemical Model Learning Framework Using Evolutionary Strategy and Simulated Annealing
The authors would like to thank the support on this research by the CRISP Project (Combinatorial Responses In Stress Pathways) funded by the BBSRC (BB/F00513X/1) under the Systems Approaches to Biological Research (SABR) Initiative.Peer reviewedPublisher PD
Marine Cyanobacteria Compounds with Anticancer Properties: Implication of Apoptosis
Marine cyanobacteria have been proved to be an important source of potential anticancer drugs. Although several compounds were found to be cytotoxic to cancer cells in culture, the pathways by which cells are affected are still poorly elucidated. For some compounds, cancer cell death was attributed to an implication of apoptosis through morphological apoptotic features, implication of caspases and proteins of the Bcl-2 family, and other mechanisms such as interference with microtubules dynamics, cell cycle arrest and inhibition of proteases other than caspases
Exome and genome sequencing of nasopharynx cancer identifies NF-κB pathway activating mutations
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