On the quantumness of correlations in nuclear magnetic resonance

Nuclear Magnetic Resonance (NMR) was successfully employed to test several protocols and ideas in Quantum Information Science. In most of these implementations the existence of entanglement was ruled out. This fact introduced concerns and questions about the quantum nature of such bench tests. In this article we address some issues related to the non-classical aspects of NMR systems. We discuss some experiments where the quantum aspects of this system are supported by quantum correlations of separable states. Such quantumness, beyond the entanglement-separability paradigm, is revealed via a departure between the quantum and the classical versions of information theory. In this scenario, the concept of quantum discord seems to play an important role. We also present an experimental implementation of an analogous of the single-photon Mach-Zehnder interferometer employing two nuclear spins to encode the interferometric paths. This experiment illustrate how non-classical correlations of separable states may be used to simulate quantum dynamics. The results obtained are completely equivalent to the optical scenario, where entanglement (between two field modes) may be present

Elastic effects on relaxation volume tensor calculations

Relaxation volume tensors quantify the effect of stress on diffusion of crystal defects. Continuum linear elasticity predicts that calculations of these parameters using periodic boundary conditions do not suffer from systematic deviations due to elastic image effects and should be independent of supercell size or symmetry. In practice, however, calculations of formation volume tensors of the interstitial in Stillinger-Weber silicon demonstrate that changes in bonding at the defect affect the elastic moduli and result in system-size dependent relaxation volumes. These vary with the inverse of the system size. Knowing the rate of convergence permits accurate estimates of these quantities from modestly sized calculations. Furthermore, within the continuum linear elasticity assumptions the average stress can be used to estimate the relaxation volume tensor from constant volume calculations.Comment: 31 pages, 6 figures, submitted to Phys. Rev.

Normalization procedure for relaxation studies in NMR quantum information processing

NMR quantum information processing studies rely on the reconstruction of the density matrix representing the so-called pseudo-pure states (PPS). An initially pure part of a PPS state undergoes unitary and non-unitary (relaxation) transformations during a computation process, causing a "loss of purity" until the equilibrium is reached. Besides, upon relaxation, the nuclear polarization varies in time, a fact which must be taken into account when comparing density matrices at different instants. Attempting to use time-fixed normalization procedures when relaxation is present, leads to various anomalies on matrices populations. On this paper we propose a method which takes into account the time-dependence of the normalization factor. From a generic form for the deviation density matrix an expression for the relaxing initial pure state is deduced. The method is exemplified with an experiment of relaxation of the concurrence of a pseudo-entangled state, which exhibits the phenomenon of sudden death, and the relaxation of the Wigner function of a pseudo-cat state.Comment: 9 pages, 5 figures, to appear in QI

Structural analysis of the O-acetylated O-polysaccharide isolated from Salmonella Paratyphi A and used for vaccine preparation

Salmonella paratyphi A is increasingly recognized as a common cause of enteric fever cases and there are no licensed vaccines against this infection. Antibodies directed against the O-polysaccharide of the lipopolysaccharide of Salmonella are protective and conjugation of the O-polysaccharide to a carrier protein represents a promising strategy for vaccine development. O-Acetylation of S. paratyphi A O-polysaccharide is considered important for the immunogenicity of S. paratyphi A conjugate vaccines. Here, as part of a programme to produce a bivalent conjugate vaccine against both S. typhi and S. paratyphi A diseases, we have fully elucidated the O-polysaccharide structure of S. paratyphi A by use of HPLC\u2013SEC, HPAEC\u2013PAD/CD, GLC, GLC\u2013MS, 1D and 2D-NMR spectroscopy. In particular, chemical and NMR studies identified the presence of O-acetyl groups on C-2 and C-3 of rhamnose in the lipopolysaccharide repeating unit, at variance with previous reports of O-acetylation at a single position. Moreover HR-MAS NMR analysis performed directly on bacterial pellets from several strains of S. paratyphi A also showed O-acetylation on C-2 and C-3 of rhamnose, thus this pattern is common and not an artefact from O-polysaccharide purification. Conjugation of the O-polysaccharide to the carrier protein had little impact on O-acetylation and therefore should not adversely affect the immunogenicity of the vaccine

Nanoparticles based on hydroxypropylcyclodextryn: preparation and in vitro viability study on Caco2 cells

The work purpose was to prepare and in vitro characterise solid nanoparticles based on hydroxypropyl-β-cyclodextrin (HP) by high pressure emulsification method; the effect on the viability of the formulations on Caco2 cells has been also evaluated

Quantum state tomography and quantum logical operations in a three qubits NMR quadrupolar system

In this work, we present an implementation of quantum logic gates and algorithms in a three effective qubits system, represented by a (I = 7/2) NMR quadrupolar nuclei. To implement these protocols we have used the strong modulating pulses (SMP). The various stages of each implementation were verified by quantum state tomography (QST). It is presented here the results for the computational base states, Toffolli logic gates, and Deutsch-Jozsa and Grover algorithms. Also, we discuss the difficulties and advantages of implementing such protocols using the SMP technique in quadrupolar systems.Comment: 24 pages, 8 figure

Poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) as possible agents in tumor treatment

Tumor eradication has many challenges due to the difficulty of selectively delivering anticancer drugs to malignant cells avoiding contact with healthy tissues/organs. The improvement of antitumor efficacy and the reduction of systemic side effects can be achieved using drug loaded nanoparticles. In this study, poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) were prepared using an emulsion polymerization method and their potential for cancer treatment was investigated. The size, polydispersity index and zeta potential of prepared nanoparticles are about 80 nm, 0.08 and −39.7 mV, respectively. The stability test shows that the formulation is stable for 15 days, while an increase in particle size occurs after 30 days. TEM reveals the spherical morphology of nanoparticles; furthermore, FTIR and 1 H NMR analyses confirm the structure of PECA-NPs and the complete polymerization. The nanoparticles demonstrate an in vitro concentration-dependent cytotoxicity against human epithelial colorectal adenocarcinoma cell lines (Caco-2), as assessed by MTT assay. The anticancer activity of PECA-NPs was studied on 3D tumor spheroids models of hepatocellular carcinoma (HepG2) and kidney adenocarcinoma cells (A498) to better understand how the nanoparticles could interact with a complex structure such as a tumor. The results confirm the antitumor activity of PECA-NPs. Therefore, these systems can be considered good candidates in tumor treatment

Non-Periodic Finite-Element Formulation of Orbital-Free Density Functional Theory

We propose an approach to perform orbital-free density functional theory calculations in a non-periodic setting using the finite-element method. We consider this a step towards constructing a seamless multi-scale approach for studying defects like vacancies, dislocations and cracks that require quantum mechanical resolution at the core and are sensitive to long range continuum stresses. In this paper, we describe a local real space variational formulation for orbital-free density functional theory, including the electrostatic terms and prove existence results. We prove the convergence of the finite-element approximation including numerical quadratures for our variational formulation. Finally, we demonstrate our method using examples

Inherently Lean Rats Have Enhanced Activity and Skeletal Muscle Response to Central Melanocortin Receptors

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143765/1/oby22166.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143765/2/oby22166_am.pd