Entangled Bell states of two electrons in coupled quantum dots—phonon decoherence

We demonstrate coupling and entangling of quantum states in a pair of vertically aligned self assembled quantum dots by studying the dynamics of two interacting electrons driven by external electric field. The present entanglement involves the spatial degree of freedom for the two electrons system. We show that system of two interacting electrons initially delocalized (localized each in one dot) oscillate slowly in response to electric field, since the strong Coulomb repulsion makes them behaving so. We use an explicit formula for the entanglement of formation of two qubit in terms of the concurrence of the density operator. In ideal situations, entangled quantum states would not decohere during processing and transmission of quantum information. However, real quantum systems will inevitably be influenced by surrounding environments. We discuss the degree of entanglement of this system in which we introduce the decoherence effect caused by the acoustic phonon. In this entangled states proposal, the decohering time depends on the external parameters.     

Immunoaffinity chromatography for the sample pretreatment of Taxus plant and cell extracts prior to analysis of taxanes by high-performance liquid chromatography

The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's main precursor in plant, were characterised by enzymed-linked immunosorbent assay. Immunoglobulins from selected antisera were immobilised on CNBr-activated Sepharose 4B. The immunoaffinity column was used for the purification of plant and plant cell culture extracts prior to their analysis by HPLC. Immunoaffinity chromatography enabled the selective concentration of taxoids and enhanced sample clean-up.     

Simultaneous quantification of levofloxacin,pefloxacin, ciprofloxacin and moxifloxacin in microvolumes of human plasma using high‐performance liquid chromatography with ultraviolet detection

Levofloxacin, pefloxacin, ciprofloxacin and moxifloxacin are four fluoroquinolones used in the treatment of serious bacterial infections. The antibacterial activity of fluoroquinolones is concentration dependent. Therefore, therapeutic drug monitoring in daily clinical practice is warranted to ensure the therapy's efficacy and prevent bacterial resistance. The purpose of the present study was to develop a method using high‐pressure liquid chromatography with an ultraviolet detector for simultaneous quantification of these four fluoroquinolones in human plasma. A 50 μL aliquot of plasma was precipitated by 200 μL of methanol using gatifloxacin as internal standard. The chromatographic separation was performed on a Kinetex XB‐C₁₈ column using a mobile phase composed of a mixture of orthophosphoric acid 0.4% (v/v), acetonitrile and methanol at a flow rate of 1.2 mL/min. Dual UV wavelength mode was used, with levofloxacin and moxifloxacin monitored at 293 nm, and pefloxacin and ciprofloxacin monitored at 280 nm. The calibration was linear over the ranges of 0.125–25 mg/L for levofloxacin, 0.1–20mg/L for moxifloxacin and 0.05‐10 mg/L for both pefloxacin and ciprofloxacin. Inter‐ and intra‐day trueness and precision were <13% for all the compounds under study. The proposed method was simple, reliable, cost‐effective and suitable for therapeutic drug monitoring or pharmacokinetics studies.     

Linear codes from support designs of ternary cyclic codes

Designs, Codes and Cryptography - For a long time, the literature has demonstrated that designs and codes are exciting topics for combinatorics and coding theory. Linear codes and t-designs are, in...     

The effects of geometrical parameters on carrier states and optical transitions in a quantum ring

Using a numerical method via the electron effective mass theory, a model of a quantum ring (QR) with a shape very close to the real one and taken from an experimental work, we investigate the electron states in a semi-conductor QR, studying the influence of the ring’s geometrical parameters on the electron spectrum and on the optical transitions. Our hetero structure evolves from a single quantum dot (QD) to a QR. We find that the one-electron ground state presents an absolute minimum when studied as a function of the ring radius. The reliability of the calculations is checked with experimental data.     

Vibrational enhancement of the effective donor-acceptor coupling

This letter deals with a simple three-site model for charge transfer phenomena in a one-dimensional donor (D)-bridge (B)-acceptor (A) system coupled with vibrational dynamics of the B site. It is found that, in a certain range of parameters, the vibrational coupling leads to an enhancement of the effective donor-acceptor electronic coupling as a result of the formation of the polaron on the B site. This enhancement of the charge transfer efficiency is maximum at the resonance, where the effective energy of the fluctuating B site coincides with the donor (acceptor) energy.     

Good polynomials for optimal LRC of low locality

Designs, Codes and Cryptography - According to a magnific method due to I. Tamo and A. Barg, a class of polynomials over finite fields, called good polynomials, was introduced and used to construct...     

Price coordination in distribution channels: A dynamic perspective

In this study, we investigate two important questions related to dynamic pricing in distribution channels: (i) Are coordinated pricing decisions efficient in a context where prices have carry-over effects on demand? (ii) Should firms practice a skimming or a penetration strategy if they choose to coordinate or to decentralize their activities? To answer these questions, we consider a differential game that takes place in a bilateral monopoly where the past retail prices paid by consumers contribute to the building of a reference price. The latter is used by consumers as a benchmark to evaluate the value of the product, and by firms to decide whether to adopt a skimming or a penetration strategy.     

Reactivity of an aminopyridine [LMnII]2+ complex with H2O2. Detection of intermediates at low temperature

In the present work we report the reactivity of [LMnII]2+ toward addition of hydrogen peroxide (H2O2) in acetonitrile solution, where L is a pentadentate polypyridine ligand. Formation of peroxo complexes is evidenced by low-temperature UV-visible spectroscopy, ESI-mass spectrometry, and EPR spectroscopy using parallel as well as perpendicular mode detection. The influence of the medium (basicity, water content) on the formation of various species is investigated. In basic nonanhydrous medium the fate of the reaction mixture solution is the formation of the di-mu-oxo mixed-valent Mn(III)Mn(IV) dinuclear complex. In acidic medium the building of the oxo bridges is avoided and the reaction mixture evolves toward oxidation of the ligand L. This reaction route offers new opportunities for the study of oxidation reactivity of Mn (hydro)peroxo complexes.