Real-time counting of single electron tunneling through a T-shaped double quantum dot system

Real-time detection of single electron tunneling through a T-shaped double quantum dot is simulated, based on a Monte Carlo scheme. The double dot is embedded in a dissipative environment and the presence of electrons on the double dot is detected with a nearby quantum point contact. We demonstrate directly the bunching behavior in electron transport, which leads eventually to a super-Poissonian noise. Particularly, in the context of full counting statistics, we investigate the essential difference between the dephasing mechanisms induced by the quantum point contact detection and the coupling to the external phonon bath. A number of intriguing noise features associated with various transport mechanisms are revealed.Comment: 8 pages, 5 figure

Fault-tolerant aggregation: Flow-Updating meets Mass-Distribution

Flow-Updating (FU) is a fault-tolerant technique that has proved to be efficient in practice for the distributed computation of aggregate functions in communication networks where individual processors do not have access to global information. Previous distributed aggregation protocols, based on repeated sharing of input values (or mass) among processors, sometimes called Mass-Distribution (MD) protocols, are not resilient to communication failures (or message loss) because such failures yield a loss of mass. In this paper, we present a protocol which we call Mass-Distribution with Flow-Updating (MDFU). We obtain MDFU by applying FU techniques to classic MD. We analyze the convergence time of MDFU showing that stochastic message loss produces low overhead. This is the first convergence proof of an FU-based algorithm. We evaluate MDFU experimentally, comparing it with previous MD and FU protocols, and verifying the behavior predicted by the analysis. Finally, given that MDFU incurs a fixed deviation proportional to the message-loss rate, we adjust the accuracy of MDFU heuristically in a new protocol called MDFU with Linear Prediction (MDFU-LP). The evaluation shows that both MDFU and MDFU-LP behave very well in practice, even under high rates of message loss and even changing the input values dynamically.- A preliminary version of this work appeared in [2]. This work was partially supported by the National Science Foundation (CNS-1408782, IIS-1247750); the National Institutes of Health (CA198952-01); EMC, Inc.; Pace University Seidenberg School of CSIS; and by Project "Coral - Sustainable Ocean Exploitation: Tools and Sensors/NORTE-01-0145-FEDER-000036" financed by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

Comparison of lansoprazole-based triple and dual therapy for treatment of Helicobacter pylori-related duodenal ulcer: An Asian multicentre double-blind randomized placebo controlled study

Background: In Asian countries with limited resources, clarithromycin-based triple therapy may not be readily available. There are also few direct comparisons of different regimens in Asia. Aim: To compare two lansoprazole-based non-clarithromycin triple therapies and one dual therapy in a prospective double-blind placebo-controlled study of Helicobacter pylori eradication and duodenal ulcer healing. Methods: Fourteen centres in Asia participated in this study. Patients with acute duodenal ulcer who were H. pylori-positive were recruited. They were randomized to receive: (a) lansoprazole 30 mg b.d., amoxycillin 1 g b.d. and metronidazole 500 mg b.d. for 2 weeks (LAM-2 W), or (b) LAM for 1 week and placebo (LAM-1 W), or (c) lansoprazole 30 mg b.d., amoxycillin 1 g b.d. and placebo for 2 weeks (LA-2 W). Upper endoscopy was repeated at week 6 to check for duodenal ulcer healing. Symptoms and side-effects were recorded. Results: A total of 228 patients were recruited, and two patients took less than 50% of the drugs. H. pylori eradication rates (intention-to-treat) were 68 out of 82 (83%) with LAM-2 W, 55 out of 71 (78%) with LAM-1 W and 43 out of 75 (57%) with LA-2 W. There were significant differences (P = 0.001) in eradication rates when comparing either LAM-2 W or LAM-1 W with LA-2 W. The eradication rate in patients with metronidazole resistant H. pylori strains were significantly lower than those with metronidazole sensitive strains (P = 0.0001). The duodenal ulcer healing rates at week 6 were 85%, 85% and 72% in LAM-2 W, LAM-1 W and LA-2 W, respectively (P = 0.065). Side-effects occurred in 13%, 11% and 9% in LAM-2 W, LAM-1 W and LA-2 W, respectively. H. pylori eradication and initial ulcer size were factors affecting duodenal ulcer healing. Conclusions: This Asian multicentre study showed that 1-week lansoprazole-based triple therapy without clarithromycin has similar efficacy in H. pylori eradication and ulcer healing compared with a 2-week regimen. Both triple therapies were significantly better than dual therapy in H. pylori eradication. Therefore, 1-week lansoprazole-based triple therapy is as safe and effective as 2-week therapy in eradication of a pylori infection and healing of duodenal ulcer in these Asian centres.postprin

In situ interface engineering for probing the limit of quantum dot photovoltaic devices.

Quantum dot (QD) photovoltaic devices are attractive for their low-cost synthesis, tunable band gap and potentially high power conversion efficiency (PCE). However, the experimentally achieved efficiency to date remains far from ideal. Here, we report an in-situ fabrication and investigation of single TiO2-nanowire/CdSe-QD heterojunction solar cell (QDHSC) using a custom-designed photoelectric transmission electron microscope (TEM) holder. A mobile counter electrode is used to precisely tune the interface area for in situ photoelectrical measurements, which reveals a strong interface area dependent PCE. Theoretical simulations show that the simplified single nanowire solar cell structure can minimize the interface area and associated charge scattering to enable an efficient charge collection. Additionally, the optical antenna effect of nanowire-based QDHSCs can further enhance the absorption and boost the PCE. This study establishes a robust 'nanolab' platform in a TEM for in situ photoelectrical studies and provides valuable insight into the interfacial effects in nanoscale solar cells

First analysis of anisotropic flow with Lee--Yang zeroes

We report on the first analysis of directed and elliptic flow with the new method of Lee--Yang zeroes. Experimental data are presented for Ru+Ru reactions at 1.69 AGeV measured with the FOPI detector at SIS/GSI. The results obtained with several methods, based on the event-plane reconstruction, on Lee--Yang zeroes, and on multi-particle cumulants (up to 5th order) applied for the first time at SIS energies, are compared. They show conclusive evidence that azimuthal correlations between nucleons and composite particles at this energy are largely dominated by anisotropic flow.Comment: 5 pages, 3 figures, submitted to Phys. Rev. C Rapid Co

Separation of Anti-Proliferation and Anti-Apoptotic Functions of Retinoblastoma Protein through Targeted Mutations of Its A/B Domain

BACKGROUND: The human retinoblastoma susceptibility gene encodes a nuclear phosphoprotein RB, which is a negative regulator of cell proliferation. The growth suppression function of RB requires an evolutionarily conserved A/B domain that contains two distinct peptide-binding pockets. At the A/B interface is a binding site for the C-terminal trans-activation domain of E2F. Within the B-domain is a binding site for proteins containing the LxCxE peptide motif. METHODOLOGY/PRINCIPLE FINDINGS: Based on the crystal structure of the A/B domain, we have constructed an RB-K530A/N757F (KN) mutant to disrupt the E2F- and LxCxE-binding pockets. The RB-K530A (K) mutant is sufficient to inactivate the E2F-binding pocket, whereas the RB-N757F (N) mutant is sufficient to inactivate the LxCxE-binding pocket. Each single mutant inhibits cell proliferation, but the RB-KN double mutant is defective in growth suppression. Nevertheless, the RB-KN mutant is capable of reducing etoposide-induced apoptosis. CONCLUSION/SIGNIFICANCE: Previous studies have established that RB-dependent G1-arrest can confer resistance to DNA damage-induced apoptosis. Results from this study demonstrate that RB can also inhibit apoptosis independent of growth suppression