Optimal Estimate of a Pure Qubit State from Uhlmann–Josza Fidelity

In the framework of collective measurements, efforts have been made to reconstruct one-qubit states. Such schemes find an obstacle in the no-cloning theorem, which prevents full reconstruction of a quantum state. Quantum Mechanics thus restricts us to obtaining estimates of the reconstruction of a pure qubit. We discuss the optimal estimate on the basis of the Uhlmann–Josza fidelity, respecting the limitations imposed by the no-cloning theorem. We derive a realistic optimal expression for the average fidelity. Our formalism also introduces an optimization parameter L. Values close to zero imply full reconstruction of the qubit (i.?e., the classical limit), while larger L’s represent good quantum optimization of the qubit estimate. The parameter L is interpreted as the degree of quantumness of the average fidelity associated with the reconstruction.     

Trapping and injecting single domain walls in magnetic wire by local fields

A single domain wall (DW) moves at linearly increasing velocity under an increasing homogeneous drive magnetic field. Present experiments show that the DW is braked and finally trapped at a given position when an additional antiparallel local magnetic field is applied. That position and its velocity are further controlled by suitable tuning of the local field. In turn, the parallel local field of small amplitude does not significantly affect the effective wall speed at long distance, although it generates tail-to-tail and head-to-head pairs of walls moving along opposite directions when that field is strong enough.     

Scattering forces and electromagnetic momentum density in crossed circularly polarized standing waves

We analyze the forces on a small dipolar particle and the electromagnetic momentum density in a configuration consisting in two perpendicular circularly polarized stationary waves. The field distribution shows regions in which the electric and magnetic fields are parallel corresponding to a null Poynting vector. Although the average value of the momentum density, proportional to the Poynting vector, is zero in these regions, there are scattering forces acting on small particles due to light's spin force. The total scattering force suggests a new definition of the average value of the momentum density for free propagating electromagnetic fields.     

Comparative study of the in vitro bioactivities of Bupleurum rigidum and B. fruticescens

Decoctions of the aerial parts of either Bupleurum rigidum or B. fruticescens are equally used in certain parts of Spain for the treatment of topical and musculoskeletal inflammations. In the present paper, their phytochemical profile and pharmacological value has been compared. After chromatographic and spectral analyses we could establish the presence of rutin and absence of chlorogenic acid in B. fruticescens, whilst the contrary applies to B. rigidum, providing a means to chemically differentiate extracts and dry materials from the two species. Their free radical scavenging and antiperoxidative activities were similar, with B. fruticescens being more active overall. The infusions of both Bupleurum species also showed similar anti-inflammatory activity when tested by NF-kappaB assay (40% and 42% at 60 microg x mL(-1)), as well as in a hexosaminidase exocytosis assay (30% at 50 microg x mL(-1)). Antimigratory effects on rat melanoma B16F10 showed significant activity for both infusions, with B. rigidum twice as potent as B. fruticescens, the activity of the latter not being fully explained by its content of rutin. Taking all these results together, we can conclude that, in the selected experimental models, there exist an in vitro bioequivalence of the infusions from both species, which is in agreement with the majority of ethnopharmacological reports.     

Structural study of six cycloalkylammonium cinnamate salt structures featuring one‐dimensional columns and two‐dimensional hydrogen‐bonded networks

Six ammonium carboxylate salts, namely cyclopentylammonium cinnamate, C₅H₁₂N⁺·C₉H₇O₂⁻, (I), cyclohexylammonium cinnamate, C₆H₁₄N⁺·C₉H₇O₂⁻, (II), cycloheptylammonium cinnamate form I, C₇H₁₆N⁺·C₉H₇O₂⁻, (IIIa), and form II, (IIIb), cyclooctylammonium cinnamate, C₈H₁₈N⁺·C₉H₇O₂⁻, (IV), and cyclododecylammonium cinnamate, C₁₂H₂₆N⁺·C₉H₇O₂⁻, (V), are reported. Salts (II)–(V) all have a 1:1 ratio of cation to anion and feature three N⁺—H...O⁻ hydrogen bonds forming one‐dimensional hydrogen‐bonded columns consisting of repeating R₄³(10) rings, while salt (I) has a two‐dimensional network made up of alternating R₄⁴(12) and R⁶₈(20) rings. Salt (III) consists of two polymorphic forms, viz. form I having Z′ = 1 and form II with Z′ = 2. The latter polymorph has disorder of the cycloheptane rings in the two cations, as well as whole‐molecule disorder of one of the cinnamate anions. A similar, but ordered, Z′ = 2 structure is seen in salt (IV).     

Helical self‐assembly of 2‐(1,4,7,10‐tetraazacyclododecan‐1‐yl)cyclohexan‐1‐ol (cycyclen)

The title macrocyclic amino alcohol compound, C₁₄H₃₀N₄O, is investigated as a solid‐state synthon for the design of a self‐assembled tubular structure. It crystallizes in a helical column constructed by stereospecific O—H...N and N—H...N interactions. The hydrogen‐bonding interactions, dependent upon macrocyclic ring helicity and molecular conformation, link R,R and S,S enantiomers in a head‐to‐tail fashion, forming a continuous hydrophilic inner core.     

Frequent hypercyclicity,chaos, and unconditional Schauder decompositions

We prove that if X is any complex separable infinite-dimensional Banach space with an unconditional Schauder decomposition, X supports an operator T which is chaotic and frequently hypercyclic. In contrast with the complex case, we observe that there are real Banach spaces with an unconditional basis which support no chaotic operator.     

Improvement of the modeling of the low-temperature oxidation of n-butane: study of the primary reactions

This paper revisits the primary reactions involved in the oxidation of n-butane from low to intermediate temperatures (550-800 K) including the negative temperature coefficient (NTC) zone. A model that was automatically generated is used as a starting point and a large number of thermochemical and kinetic data are then re-estimated. The kinetic data of the isomerization of alkylperoxy radicals giving (?)QOOH radicals and the subsequent decomposition to give cyclic ethers has been calculated at the CBS-QB3 level of theory. The newly obtained model allows a satisfactory prediction of experimental data recently obtained in a jet-stirred reactor and in rapid compression machines. A considerable improvement of the prediction of the selectivity of cyclic ethers is especially obtained compared to previous models. Linear and global sensitivity analyses have been performed to better understand which reactions are of influence in the NTC zone.     

Investigation on the protective effects of cranberry against the DNA damage induced by benzo[a]pyrene

There are few reports that demonstrate the antigenotoxic potential of cranberries. Although the types of berry fruits consumed worldwide are many, this paper focuses on cranberries that are commonly consumed in Mexico (Vaccinium macrocarpon species). The purpose of the present study is to determine whether cranberry ethanolic extract (CEE) can prevent the DNA damage produced by benzo[a]pyrene (B[a]P) using an in vivo mouse peripheral blood micronucleus assay. The experimental groups were organized as follows: a negative control group (without treatment), a positive group treated with B[a]P (200 mg/kg), a group administered with 800 mg/kg of CEE, and three groups treated with B[a]P and CEE (200, 400, and 800 mg/kg) respectively. The CEE and benzo[a]pyrene were administered orally for a week, on a daily basis. During this period the body weight, the feed intake, and the determination of antigenotoxic potential were quantified. At the end of this period, we continued with the same determinations for one week more (recovery period) but anymore administration of the substances. The animals treated with B[a]P showed a weight increase after the first week of administration. The same phenomenon was observed in the lots combined with B[a]P and CEE (low and medium doses). The dose of 800 mg/kg of CEE showed similar values to the control group at the end of the treatment period. In the second part of the assay, when the substances were not administered, these experimental groups regained their normal weight. The dose of CEE (800 mg/kg) was not genotoxic nor cytotoxic. On the contrary, the B[a]P increases the frequency of micronucleated normochromatic erythrocytes (MNNE) and reduces the rate of polychromatic erythrocytes (PE) at the end of the treatment period. With respect to the combined lots, a significant decrease in the MN rate was observed from the sixth to the eighth day of treatment with the two high doses applied; the highest protection (60%) was obtained with 800 mg/kg of CEE. The same dose showed an anticytotoxic effect which corresponded to an improvement of 62.5% in relation to the animals administered with the B[a]P. In the second period, all groups reached values that have been seen in the control group animals. Our results suggest that the inhibition of clastogenicity of the cranberry ethanolic extract against B[a]P is related to the antioxidant capacity of the combination of phytochemicals present in its chemical composition.     

Improved signal-to-noise ratio in laboratory-based phase contrast tomography

In conventional X-ray microtomography (μCT), the three-dimensional (3D) distribution of the attenuation coefficient of X-rays is measured and reconstructed in a 3D volume. As spatial resolution increases, the refraction of X-rays becomes a significant phenomenon in the imaging process. Although this so-called phase contrast was initially a cumbersome feature in lab-based μCT, special phase retrieval algorithms were developed to exploit these effects. Clear advantages in terms of visualization and analysis can be seen when phase retrieval algorithms are applied, including an increased signal-to-noise ratio. In this work, this is demonstrated both on simulated and measured data.