Photon assisted tunneling through three quantum dots with spin-orbit-coupling

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Entry of Not-for-Profit Food Cooperatives and Its Implications on For-Profit Retailers

Propelled by the recent social activism that calls for not-for-profit food cooperatives (coops) to address the food desert and job desert issues, more food coops are establishing their presence in less-populated areas or poor communities. This trend has motivated us to examine the entry conditions for food coops with the following two related social missions: (A) maximize reserve to support the local community needs; and (B) maximize sales to support the local economy. We present a game-theoretic model to analyze the competition between an entrant not-for-profit coop and an incumbent for-profit retailer in a market comprising heterogeneous consumers with different annual consumption rates and social benefit levels. We examine the coop's pricing strategy and entry conditions, the impact of the coop's entry on the retailer's profit, and the conditions under which the retailer should deter the coop's entry. Our analytical results indicate that a coop can afford to enter the market only when its fixed annual operating cost is below a certain threshold. Upon entry, it is optimal for the coop to set a membership fee and a member-only discount to attract at least those consumers with high consumption rate. We show that the coop’s entry is detrimental for the retailer. However, interestingly, even if the retailer can profitably deter the coop’s entry, it is actually optimal for the retailer to tolerate it when the coop's annual fixed operating cost is below a threshold, where this threshold is lower for a coop with mission (B) than mission (A)

Inhibitory Effect of Polysaccharides from Scutellaria barbata D. Don on Invasion and Metastasis of 95-D Cells Lines via Regulation of C-MET and E-CAD Expressions

Purpose: To investigate the inhibitory effect of polysaccharides from Scutellaria barbata (PSB) on invasion and metastasis of lung cancer, and study the possible mechanism.Methods: PSB was extracted with water and by alcohol precipitation, and purified by DEAE-52 column chromatography. A highly invasive and metastatic lung carcinoma cell, 95-D cell line, was used for the study. Cell adhesion and invasion assays in vitro were performed to evaluate the anti-invasive and antimetastatic effects of PSB (50 - 200 μg/ml) on 95-D cell. Immunocytochemical staining and Western blot techniques were employed to study the regulatory effects of PSB on the expression of C-MET and ECAD.Results: The results indicate that PSB significantly inhibited cell invasion and migration of 95-D in a concentration-dependent manner (p < 0.05). The adhesion of 95-D cells to fibronectin was also inhibited by PSB (p < 0.05). The expression of C-MET and E-CAD in 95-D cells treated with PSB were significantly down-regulated and up-regulated, respectivelt (p < 0.05).Conclusion: Treatment with PSB can significantly inhibit the invasion and metastasis of 95-D cells in vitro, probably through the regulation of C-MET and E-CAD.Keywords: Polysaccharide, Scutellaria barbata, 95-D cell lines, Invasion, Metastasi

Potential of mean force and the charge reversal of rodlike polyions

A simple model is presented to calculate the potential of mean force between a polyion and a multivalent counterion inside a polyelectrolite solution. We find that under certain conditions the electrostatic interactions can lead to a strong attraction between the polyions and the multivalent counterions, favoring formation of overcharged polyion-counterion complexes. It is found that small concentrations of salt enhance the overcharging, while an excessive amount of salt hinders the charge reversal. The kinetic limitations to overcharging are also examined.Comment: To be published in the special issue of Molecular Physics in honor of Prof. Ben Wido

InAs/GaAs Quantum-Dot Lasers Monolithically Grown on on-axis Silicon (001)

Inversion boundaries (IBs) are charged planer defects that arise from the growth of polar III-V materials on non-polar Si (001) substrate. This paper demonstrates a novel technique to achieve all-MBE grown, IB-free GaAs on on-axis Si (001) substrates by employing periodic Si single-atomicheight steps to re-distribute the nucleation of IBs and promote IB self-annihilation in the subsequent GaAs growth. Furthermore, an electronically pumped quantum-dot (QD) laser has been demonstrated on this IB-free GaAs/Si platform with a maximum operating temperature of 120 °C. These results could be a significant step towards the monolithic integration of III-V materials and devices with mature CMOS technology

Key Parameters That Determine the Magnitude of the Decrease in Current in Nanopore Blockade Sensors

Nanopore blockade sensors were developed to address the challenges of sensitivity and selectivity for conventional nanopore sensors. To date, the parameters affecting the current of the sensor have not been elucidated. Herein, the impacts of nanopore size and charge and the shape, size, surface charge, and aggregation state of magnetic nanoparticles were assessed. The sensor was tolerant to all parameters contrary to predictions from electronic or geometric arguments on the current change. Theoretical models showed the greater importance of the polymers around nanoparticles and the access resistance of nanopores to the current, when compared with translocation-based nanopore sensors. The signal magnitude was dominated by the change in access resistance of ∼4.25 Mω for all parameters, resulting in a robust system. The findings provide understandings of changes in current when nanopores are blocked, like in RNA trapping or nanopore blockade sensors, and are important for designing sensors based on nanopore blockades

Imaging with therapeutic acoustic wavelets–short pulses enable acoustic localization when time of arrival is combined with delay and sum

—Passive acoustic mapping (PAM) is an algorithm that reconstructs the location of acoustic sources using an array of receivers. This technique can monitor therapeutic ultrasound procedures to confirm the spatial distribution and amount of microbubble activity induced. Current PAM algorithms have an excellentlateral resolution but have a poor axial resolution, making it difficult to distinguish acoustic sources within the ultrasound beams. With recent studies demonstrating that short-length and low-pressure pulses—acoustic wavelets—have the therapeutic function, we hypothesizedthat the axial resolution could be improved with a quasi-pulse-echo approach and that the resolution improvement would depend on the wavelet’s pulse length. This article describes an algorithm that resolves acoustic sources axially using time of flight and laterally using delayand-sum beamforming, which we named axial temporal position PAM (ATP-PAM). The algorithm accommodates a rapid short pulse (RaSP) sequence that can safely deliver drugs across the blood–brain barrier. We developed our algorithm with simulations (k-wave) and in vitro experiments for one-, two-, and five-cycle pulses, comparing our resolution against that of two current PAM algorithms. We then tested ATP-PAM in vivo and evaluated whether the reconstructed acoustic sources mapped to drug deliver

Template-free synthesis of hierarchical hollow V2O5 microspheres with highly stable lithium storage capacity

Hollow V2O5 microspheres were successfully synthesized by a solvothermal method and subsequent calcination. The rigid hollow V2O5 cathode prepared in isopropanol solvent exhibited excellent cycling performance and rate capability. Within a voltage window of 2.5 to 4 V, a maximum specific discharge capacity of 128 mA h g−1 was delivered at 1 A g−1. Even after 500 cycles, the capacity retention was 92.2%.published_or_final_versio

Control of Emi2 activity and stability through Mos-mediated recruitment of PP2A.

Before fertilization, vertebrate eggs are arrested in meiosis II by cytostatic factor (CSF), which holds the anaphase-promoting complex (APC) in an inactive state. It was recently reported that Mos, an integral component of CSF, acts in part by promoting the Rsk-mediated phosphorylation of the APC inhibitor Emi2/Erp1. We report here that Rsk phosphorylation of Emi2 promotes its interaction with the protein phosphatase PP2A. Emi2 residues adjacent to the Rsk phosphorylation site were important for PP2A binding. An Emi2 mutant that retained Rsk phosphorylation but lacked PP2A binding could not be modulated by Mos. PP2A bound to Emi2 acted on two distinct clusters of sites phosphorylated by Cdc2, one responsible for modulating its stability during CSF arrest and one that controls binding to the APC. These findings provide a molecular mechanism for Mos action in promoting CSF arrest and also define an unusual mechanism, whereby protein phosphorylation recruits a phosphatase for dephosphorylation of distinct sites phosphorylated by another kinase