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Background: The role of minerals in preventing the generation of oxidative stress in obese individuals has been evaluated. Magnesium is an antioxidant nutrient and a cofactor of enzymes involved in the cell membrane stabilization, attenuating the effects of oxidative stress. Objective: To evaluate the association between magnesium and concentrations of thiobarbituric acid reactive substances (TBARS) in patients with obesity and eutrophic women. Methods: A cross-sectional study was conducted with 73 women, divided into two groups: case group (patients with obesity, n=27) and control group (eutrophic women, n=46). Measurements of body mass index and waist circumference were performed. Dietary magnesium intake was assessed by the three-day food record using the NutWin software. Urinary magnesium concentration was measured by atomic absorption spectrophotometry method. Plasma concentrations of thiobarbituric acid reactive substances (TBARS) were also determined. Results: Mean values of dietary magnesium intake were 161.59 ± 60.04 and 158.73 ± 31.96 for patients with obesity and control group, respectively, with no significant difference between the groups studied (p >0.05). The value of urinary excretion of magnesium was lower than the reference values in both groups, with no significant difference between the groups studied (p >0.05). The plasma concentration of thiobarbituric acid reactive substances was significantly higher in patients with obesity compared to the control group (p 0.05). Conclusion: Patients with obesity showed a reduced dietary magnesium intake which seems to induce hypomagnesuria as a compensatory mechanism. The marker of oxidative stress evaluated in this study was not influenced by magnesium.

The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hydrolytic sol-gel methodology and doped with the lanthanide ions Er3+ and Yb3+ at a 1:1 molar ratio. The efficiency of the optical parameters was analyzed on the basis of the Er3+ green emission after excitation in the infrared region, namely 980 nm. The temperature-dependent fluorescence intensity ratio (FIR) between the thermally coupled Er3+ levels (2H11/2 and 4S3/2 → 4I15/2) was evaluated. The Er3+ emission depended on the laser power. The calculated number of photons was 2 in this case. Temperatures ranging from 298.3 to 374.5 K were assessed, and the sensitivity varied from 1.2 to 1.9% K-1, respectively. The initial temperature was estimated.

This work describes the development of an HPLC-FLD methodology for the separation of five fluoroquinolones (ciprofloxacin, enrofloxacin, sarafloxacin, norfloxacin and levofloxacin) followed by optimization of the DLLME process for the clean-up and preconcentration of enrofloxacin in samples of seawater and river water. The mobile phase used for the chromatographic separation consisted of methanol: phosphate buffer (NaHPO4 H2O 0.04 M pH 3 with H3PO4 85 %), gradient eluted at a ratio of 20:80 (v:v). The mobile phase flow was maintained at 1.2 mL min-1. For the ultrasonic-assisted dispersive liquid liquid microextraction (UA-DLLME), the following conditions were used: 8 mL of sample with pH adjusted to 8, extraction solvent: 500 μL of chloroform, dispersive solvent: 500 μL of acetonitrile; samples were vortexed and sonicated for 2 minutes, each. The enrichment factor (EF) was 54.7 and the recovery was 70 %, achieving a limit of detection (LOD) of 0.11 μg L-1. Repeatability and intermediate reproducibility presented values of relative standard deviation (RSD) lower than 2 %. Finally, the optimized method was applied to the analysis of water and enrofloxacin was detected in both water samples with a concentration of 0.20 μg L-1 in the river and 0.12 μg L-1 in the seawater. However, recovery tests performed to evaluate the water matrices' effects on the extraction performance, presented recoveries of 72±6.1 for river water and 27±8.3 for seawater. These results demonstrate that hereby developed method is only suitable for water samples with a low salinity content. published

In this work, a liquid-liquid microextraction methodology using solidified floating organic drop (SFODME) was combined with liquid chromatography and UV/Vis detection to determine non-steroidal anti-inflammatory drugs (NSAIDs) naproxen (NPX), diclofenac (DCF), and mefenamic acid (MFN) in tap water, surface water, and seawater samples. Parameters that can influence the efficiency of the process were evaluated, such as the type and volume of the extractor and dispersive solvents, effect of pH, agitation type, and ionic strength. The optimized method showed low detection limits (0.09 to 0.25 μg L-1), satisfactory recovery rates (90 to 116%), and enrichment factors in the range between 149 and 199. SFODME showed simplicity, low cost, speed, and high concentration capacity of the analytes under study. Its use in real samples did not demonstrate a matrix effect that would compromise the effectiveness of the method, being possible to apply it successfully in water samples with different characteristics. published

In this work the dispersive liquid-liquid microextraction technique (DLLME) is presented as an important alternative to the classical extraction methods and was used to extract and concentrate estrogens’ before its quantification by HPLC in environmental water samples. For the evaluation of the analytical methodology, the following conditions were used: sample volume 8 mL, extraction solvent 200 μL of chlorobenzene, and dispersive solvent 2000 μL of acetone. The enrichment factor (EF) was 140 for estrone, 202 for 17β-estradiol (E2), and 199 for 17α-ethinylestradiol (EE2). Limit of detection was 20 ng L−1 for E1, 3.1 ng L−1 for E2, and 2.7 ng L−1 for EE2. Repeatability and intermediate reproducibility presented values of relative standard deviation lower than 10%. Finally, recovery tests were performed to evaluate the water matrices’ effects on the extraction performance, resulting in recoveries between 76 and 110% in surface water and between 84 and 109% in wastewater.

The enhanced chromatographic capability of the comprehensive two-dimensional gas chromatography (GC × GC) has already found several applications in analytical chemistry comprising complex samples. However, setting the appropriate chromatographic conditions that maximize sensitivity and separation efficiency in GC × GC may be more difficult than in conventional one-dimension gas chromatography, mainly due to the additional parameters strictly related to the modulation. Loop-type cryogenic modulators have been currently used for crude oil analysis using GC × GC, requiring sometimes a laborious try-and-error procedure to properly tune the dual-jets elapsed times on modulation. In this work, the advantages of choosing a time-variable combination of cold and hot jets pulses in a loop-type cryogenic modulator is presented when performing the fingerprinting analysis of crude oils using GC × GC-QMS, contrary to the conventional procedure based on a single combination for the dual-stage jets. A design of experiments approach is proposed to most effectively optimize the time-variable combination of the dual-jets elapsed times while modulating the wide hydrocarbons range along the GC × GC analysis. The most abundant classes of hydrocarbons contained in the maltenes fraction of a crude oil sample, such as paraffins, aromatics, steranes and hopanes were successfully resolved.

The ruthenium(II) compounds cis-[Ru(bpy)2(4-bzpy)(CO)](PF6)2 (I) and cis-[Ru(bpy)2(4-bzpy)(Cl)](PF6) (II) (4-bzpy=4-benzoylpyridine, bpy=2,2'-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365nm) releases both CO and 4-bzpy leading to the formation of the cis-[Ru(bpy)2(H2O)2]2+ ion as identified by NMR and electronic spectroscopy. Carbon monoxide release was confirmed with the myoglobin method and by gas chromatographic analysis of the headspace. CO release was not observed when aqueous I was irradiated with blue light (453nm). Changes in the electronic and 1H NMR spectra indicate that I undergoes photoaquation of 4-bzpy to form cis-[Ru(bpy)2(CO)(H2O)]2+. Blue light irradiation of aqueous II released the coordinated 4-bzpy to give the cis-[Ru(bpy)2(H2O)(Cl)]2+ ion. When the latter reaction was carried out in the presence of the nucleobase guanine, Ru-guanine adducts were formed, indicating that the metal containing photoproduct may also participate in biologically relevant reactions. The photochemical behavior of I indicates that it can release either CO or 4-bzpy depending on the wavelength chosen, a feature that may have therapeutic application.

Made available in DSpace on 2018-11-28T13:17:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01. Added 1 bitstream(s) on 2021-07-15T14:31:42Z : No. of bitstreams: 1 S0100-69162017000300510.pdf: 482205 bytes, checksum: c60c0dff04983c17b9130278cb9304f6 (MD5) Semi-mechanical and mechanical harvesting methods may influence the content of impurities in harvested sugarcane. This study aimed to evaluate the quality of three mechanical methods of sugarcane harvesting: one semi-mechanical, and two mechanical ones - self-performed and outsourced, during three working shifts. As quality indicators, both mineral and vegetal impurities were accounted. About 50 random samples were collected in the studied area during 35 harvest days and in three working shifts, for each harvesting method. Mineral impurities showed similar behavior for both self-performed and outsourced mechanical harvesting, thus displaying a low variability. On the other hand, vegetal impurities showed to be unstable for all three shifts. Additionally, the statistical process control analysis showed that the semi-mechanical method had the greatest variability. Univ Estadual Paulista, Fac Ciencias Agr & Vet, Jaboticabal, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agr & Vet, Jaboticabal, SP, Brazil

Purpose: of this paper was to develop and to characterize the mechanical behaviour of a structural composite obtained from a bio-based polyurethane matrix reinforced with fiberglass. Design/methodology/approach: Castor oil and Kraft lignin-containing polyol was applied for bio-based polyurethane synthesis. Structural composite was obtained by reinforcing this renewable source bio-based polymer with fiberglass mat. Polyester resin composite was also obtained for comparison, following the same process and reinforcement conditions. Mechanical characterization was carried out through uniaxial tensile, flexural strength, Izod impact tests and additionally scanning electron microscopy (MEV). Findings: Bio-based polyurethane composite was obtained and presented higher ultimate tensile strength (UTS) and equivalent impact resistance in comparison to polyester matrix composite. Research limitations/implications: Effects of Kraft lignin and fiberglass contents changing on mechanical properties might be investigated in future researches. Practical implications: Revalorization of Kraft lignin. 50 million tons of lignin are produced worldwide every year as by-product of pulp and paper manufacturing. The most part of this Kraft lignin is currently burned for energy generation. Originality/value: Results indicated the possibility of reusing this industrial wasted by-product at large scale as polymeric matrix for structural composite, in which high UTS and impact resistance are required.

The main feature of amorphous materials is the presence of excess vibrational modes at low energies, giving rise to the so called "boson peak" in neutron and optical spectroscopy. These same modes manifest themselves as two level systems (TLSs) causing noise and decoherence in qubits and other sensitive devices. Here we present an experiment that uses the spin relaxation of dangling bonds at the Si/(amorphous)SiO$_2$ interface as a probe of TLSs. We introduce a model that is able to explain the observed non-exponential electron spin inversion recovery and provides a measure of the degree of spatial localization and concentration of the TLSs close to the interface, their maximum energy and its temperature dependence., Comment: 4 pages, 2 figures, regular paper

Metal-based compounds have emerged as a novel strategy to improve our arsenal of medicines. Among these compounds, carbon monoxide donor agents have been developed mainly as metal complexes. These compounds have shown exciting biological activities, among them strong anti-inflammatory, antibiotic, and anticancer activity, although some of those properties might be associated with the metal moiety as well. Aiming to prepare a new ruthenium complex containing CO, we prepared a cis-[RuCl(CO)(dppb)(dppz)]PF6 complex (dppb = 1,4-bis(diphenylphosphino)butane and dppz = dipyrido[3,2-a:2′,3′-c]phenazine), which was fully characterized along with DFT studies. This compound exhibited great thermal stability in phosphate buffer solution, but showed fast and efficient release of CO upon light irradiation, including blue LED. Surprisingly, DNA binding was quite weak, despite the dppz ligand moiety, suggesting that steric effects prevented intercalation binding. Nonetheless, this compound exhibited promising antibiotic activity against S. aureus, S. epidermidis and C. albicans in a low micromolar range. However, there was no further improvement upon light irradiation suggesting that there is no role of CO. Additionally, cytotoxicity assay using cancer cells showed quite low IC50 (92 nM, HCT-116) along with moderate to low toxicity assayed in lymphocytes and Artemia. Altogether, these results supported that this compound has great potential as a biological agent, whereas neither CO release nor DNA binding seemed to have a direct role in its activity.

The objective of this study was to evaluate the temporal composition of epigeous fauna during decomposition of different legume combinations in alley cropping systems. Two legume species with high quality waste Leucaena leucocephala (Leucaena) and Cajanus cajan (Pigeon pea), and two species of low quality waste Clitoria fairchildiana (Sombrero) and Acacia mangium (Acacia), were combined forming six treatments: Sombrero + Pigeon pea (S + PP); Leucaena + Pigeon pea (L + PP); Acacia + Leucaena (A + L); Sombrero + Leucaena (S + L); Acacia + Pigeon pea (A + PP) and control (without legumes). We used the litter bag method to evaluate waste quality. Each bag was filled with 20 g of leaves of the two combined legumes and distributed in the treatments and were withdrawn on the day of pruning and at 3, 6, 10, 15, 30, 60 and 90 days after legume pruning. Two pitfall traps were used to capture epiedaphic fauna in each treatment. Eight evaluations were done based on the date of legume pruning. The initial amount of N was higher in the L + PP treatment (29.31 gKg-1), which showed the highest decomposition constant, providing the fastest release of N in the soil; and presenting the lowest C/N ratio. The highest polyphenol content was found in A + L (4.84%). The soil fauna under different vegetation covers was composed mainly of Aranae, Coleoptera, Diptera, Formicidae, Coleoptera larvae, mites and Collembola; the latter two being the more abundant in all samples. The soil fauna group richness varied during the time of decomposition; the greatest diversity was recorded at 60 days after the legume pruning due to group homogeneity. Key words: Arthropods, mites, springtails, soil ecology, decomposition.

A theoretical analysis of the host/guest inclusion process involving the prilocaine into the β-cyclodextrin was performed. Structure and stabilization energies were calculated, in both gas and aqueous phases, using Density Functional Theory level of theory. As results, a qualitative structure property relationship could be established with structural features being relevant for inclusion complex stabilization: (i) the hydrogen bonds established between guest and host molecules and (ii) the dispersion effect in the formation of the complexes. Besides, a theoretical 1H NMR analysis has shown to be an adequate procedure to predict correctly the inclusion mode of guest molecule into the host.

This work aimed to evaluate the influence of the aliphatic and aromatic hydroxyl level on the polyurethane adhesive property and chemical structure. This adhesive was obtained through the reaction of technical Kraft lignin (TKL) as polyol with diphenylmethane diisocyanate (MDI). Thus, lignopolyurethane adhesives were obtained with NCO:OH ratios of 0.8:1.0, 0.9:1.0, 1.0:1.0, 1.1:1.0, and 1.2:1.0. Initially only the TKL aliphatic hydroxyl level was taken into consideration in the stoichiometry in order to define the mass ratio between MDI and polyol. Subsequently, lignopolyurethane adhesive was obtained using the same NCO:OH ratios considering TKL total hydroxyls’ level, and aromatic and aliphatic hydroxyls. The chemical structures of the synthesized adhesives were analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (13C NMR). The mechanical property of the adhesively bonded joints, comprising wood substrates and synthesized adhesives, was measured using single ...

The present letter reports, for the first time, results from a theoretical analysis of the inclusion process involving the prilocaine into the p -sulfonic acid calix[ 6 ]arene. Structure and stabilization energies were calculated, in both gas and aqueous phases, using a sequential methodology based on semiempirical and Density Functional Theory (DFT) calculations. From the results, a qualitative structure property relationship could be established with some main structural features being relevant for inclusion complex stabilization: (i) the hydrogen bonds established between guest and host molecules, (ii) the dispersion effect and (iii) the inclusion mode of guest molecule into the host cavity.

We report, for the first time, results from a comprehensive theoretical analysis of the inclusion process involving the mepivacaine (MEP) and β-cyclodextrin (β-CD). Structure and complexation energies were calculated, in both gas and aqueous phases, using the Density Functional Theory (DFT) level of theory. The structural analysis pointed out that intermolecular hydrogen bond established between MEP (Mode A of inclusion) with the β-CD play a major role on the complex stabilization, which is supported by bond order analysis. Besides, from the dipole moments analysis, it can be concluded that the β-CD cavity serves as a polar medium for the drug.

We proposed the use of the available data of a Wireless Sensor Network (WSN) for determining the static characteristics and studying the dynamic behavior of the propagation channel. Channel path-loss and shadowing parameters were evaluated for two distinct locations, an office environment and a hydroelectric power plant, over different days using only the Received Signal Strength Indicator (RSSI) measurements reported by the nodes of a mesh network. The office environment estimated path-loss coefficient and the shadowing distribution standard deviation were within 4.5–4.6 and 8.1–8.2 dB, respectively, as expected for this kind of environment. Moreover, the power plant indoor-outdoor links presented a path-loss coefficient between 5.2–6.5 and shadowing standard deviation between 3.6–4.3 dB. The inspection of the data obtained from the network over long periods of time also proved invaluable, specially helping to identify and correlate sources of interference, which can lead to improve the design of the network itself in industrial scenarios.

Soil preparation along with its chemical adjustment is the most important step in sugarcane plantation, especially because it provides proper conditions for plant development. The objective of the present research was to evaluate sugarcane response to the application of different phosphorus doses and their location, associated with both minimum soil tillage and conventional soil tillage. The experiment was conducted in a split-split-plot randomized block design, where the main plots were subjected to soil managements (minimum soil tillage or conventional soil tillage), the subplots to phosphorus doses in total area, and the sub-sub-plots to phosphorus doses in the crop rows. The evaluated variables were soil chemical parameters, sugarcane production and sugar production. Minimum tillage led to larger phosphorus accumulation and higher percentage of exchangeable bases in the soil, whereas the highest P dose in total area in the crop rows led to reduction of sugar production. RESUMO O preparo do solo realizado concomitantemente com sua fertilização química é a etapa mais importante na instalação de um canavial, visto que proporciona melhores condições para o desenvolvimento da cultura e incrementos na produtividade. Assim, objetivou-se, no presente trabalho, avaliar a resposta da cana-de-açúcar à aplicação de diferentes doses de fosfóro e sua localização, associados ao preparo convencional e ao cultivo mínimo do solo. O delineamento experimental utilizado foi em blocos inteiramente casualizados com parcelas subdivididas, sendo o tratamento principal o manejo de solo (preparo convencional e cultivo mínimo), o tratamento secundário as doses em área total, e o tratamento terciário as doses de P2O5 nos sulcos. Foram avaliados parâmetros químicos do solo, produtividade de colmos e açúcar. O cultivo mínimo proporcionou maior acúmulo de fósforo e maior percentual de saturação por bases na camada superficial do solo, enquanto que a maior dose de fósforo em área total gerou redução na produção de açúcar.

One of the widely used algorithms for graph-based semi-supervised learning (SSL) is the Local and Global Consistency (LGC). Such an algorithm can be viewed as a convex optimization problem that balances fitness on labeled examples and smoothness on the graph using a graph Laplacian. In this paper, we provide a novel graph-based SSL algorithm incorporating two normalization constraints into the regularization framework of LGC. We prove that our method has closed-form solution and generalizes two existing methods, being more flexible than the original ones. Through experiments on benchmark data sets, we show the effectiveness of our method, which consistently outperforms the competing methods.

A theoretical (1)H NMR spectroscopy and thermodynamic analysis of the host-guest inclusion process involving the norfloxacin (NFX) into β-cyclodextrin (β-CD) was carried out. DFT structure and stabilization energies were obtained in both gas and aqueous phases. We could establish that the complex formation is enthalpy driven, and the hydrogen bonds established between NFX and β-CD play a major role in the complex stabilization. Besides, a theoretical (1)H NMR analysis has shown to be a supplementary proceeding to predict appropriately the inclusion mode of norfloxacin molecule into the β-CD. In this work, a theoretical study of the NFX@β-CD complex is reported for the first time, seeking a deep understanding of topology and thermodynamics of the inclusion complex formation. Graphical Abstract Topology, thermodynamic and (1)H NMR analysis of NFX@β-CD host-guest complexes.

The influence of spin-orbit interactions on the Kondo effect has been under debate recently. Studies conducted recently on a system composed by an Anderson impurity on a 2DEG with Rashba spin-orbit have been shown that it can enhance or suppress the Kondo temperature ($T_{\rm K}$), depending on the relative energy level position of the impurity with respect to the particle-hole symmetric point. Here we investigate a system composed by a single Anderson impurity side-coupled to a quantum wire with spin-orbit coupling (SOC). We derive an effective Hamiltonian in which the Kondo coupling is modified by the SOC. In addition, the Hamiltonian contains two other scattering terms, the so called Dzaloshinskyi-Moriya interaction, know to appear in these systems, and a new one describing processes similar to the Elliott-Yafet scattering mechanisms. By performing a renormalization group analysis on the effective Hamiltonian, we find that the correction on the Kondo coupling due to the SOC favors and enhancement of the Kondo temperature even in the particle-hole symmetric point of the Anderson model, agreeing with the NRG results. Moreover, away from the particle-hole symmetric point, $T_{\rm K}$ always increases with the SOC, accordingly with the previous renormalization group analysis., 9 pages, 3 figures

Graph-based semi-supervised learning (SSL) algorithms learn through a weighted graph generated from both labeled and unlabeled examples. Despite the effectiveness of these methods on a variety of application domains, most of them are transductive in nature. Therefore, they are uncapable to provide generalization for the entire sample space. One of the most effective graph-based SSL algorithms is the Local and Global Consistency (LGC), which is formulated as a convex optimization problem that balances fitness on labeled examples and smoothness on the weighted graph through a Laplacian regularizer term. In this paper, we provide a novel inductive procedure for the LGC algorithm, called Inductive Local and Global Consistency (iLGC). Through experiments on inductive SSL using a variety of benchmark data sets, we show that our method is competitive with the commonly used Nadaraya-Watson kernel regression when applying the LGC algorithm as basis classifier.

Optical spectroscopy has been combined with computational and theoretical techniques to show how the spin dynamics in the model multiferroic BiFeO3 responds to the application of hydrostatic pressure and its corresponding series of structural phase transitions from R3c to the Pnma phases. As pressure increases, multiple spin excitations associated with non-collinear cycloidal magnetism collapse into two excitations, which show jump discontinuities at some of the ensuing crystal phase transitions. Effective Hamiltonian approach provides information on the electrical polarization and structural changes of the oxygen octahedra through the successive structural phases. The extracted parameters are then used in a Ginzburg-Landau model to reproduce the evolution with pressure of the spin waves excitations observed at low energy and we demonstrate that the structural phases and the magnetic anisotropy drive and control the spin excitations., 5 pages, 4 figures

We report on the vortex transport in ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Y}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8}$ single crystals irradiated in a parallel direction with the c axis with 5.8-GeV Pb ions at fluences of $3.75\ifmmode\times\else\texttimes\fi{}{10}^{10}{\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ and $7.5\ifmmode\times\else\texttimes\fi{}{10}^{10}{\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}.$ A detailed investigation of the vortex transport using current-voltage measurements is carried out with the magnetic field applied along the c axis. First, we investigate the critical behavior of the linear and nonlinear conductivity near the Bose-glass melting line. We obtain field and sample-independent critical exponents ${z}^{\ensuremath{'}}$ and ${\ensuremath{\nu}}^{\ensuremath{'}}$ consistent with a compressible Bose glass (i.e., ${\ensuremath{\nu}}_{\ensuremath{\parallel}}=2{\ensuremath{\nu}}_{\ensuremath{\perp}}\ensuremath{\equiv}2{\ensuremath{\nu}}^{\ensuremath{'}}).$ Using the values ${z}^{\ensuremath{'}}=5.28\ifmmode\pm\else\textpm\fi{}0.05$ and ${\ensuremath{\nu}}^{\ensuremath{'}}=1.04\ifmmode\pm\else\textpm\fi{}0.06,$ the data collapse into two single-scaling functions. Second, we report on conductivity measurements over a wide filling factor ${(B/B}_{\ensuremath{\varphi}})$ range from 0.04 up to 0.9 within the Bose-glass phase. Our data provide support for a variable-range hopping mechanism for low current densities, in accordance with the ideas of Nelson and Vinokur [Phys. Rev. B 48, 13 060 (1993)]. We determine a glass exponent value of 1/3 for all the filling factors investigated at large ratios of the penetration depth to the average defect distance $({\ensuremath{\lambda}}_{\mathrm{ab}}/d\ensuremath{\sim}10).$ This finding implies that no Coulomb gap occurs in the pinning energy spectrum. Furthermore, our results show that for low filling factors (1/2) the on-site disorder plays a major role in the bandwidth of flux-binding energies. Finally, the appearance of a well-defined crossover near half filling is consistent with the field ${B}^{*}$ separating the strongly pinned Bose-glass regime from the weakly pinned Bose-glass regime.

To face the challenges lying beyond current CMOS-based technology, new paradigms for information processing are required. Magnonics proposes to use spin waves to carry and process information, in analogy with photonics that relies on light waves, with several advantageous features such as potential operation in the THz range and excellent coupling to spintronics. Several magnonic analog and digital logic devices have been proposed, and some demonstrated. Just as for spintronics, a key issue for magnonics is the large power required to control/write information (conventionally achieved through magnetic fields applied by strip lines, or by spin transfer from large spin-polarized currents). Here we show that in BiFeO3, a room-temperature magnetoelectric material, the spin wave frequency (>600 GHz) can be tuned electrically by over 30%, in a non-volatile way and with virtually no power dissipation. Theoretical calculations indicate that this effect originates from a linear magnetoelectric effect related to spin-orbit coupling induced by the applied electric field. We argue that these properties make BiFeO3 a promising medium for spin wave generation, conversion and control in future magnonics architectures., 3 figures

We implanted ultra low doses (2x10^11 cm-2) of 121Sb ions into isotopically enriched 28Si and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2 K, a spin decoherence time, T2, of 0.3 ms is found for profiles peaking 50 nm below a Si/SiO2 interface, increasing to 0.75 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins.

The transverse Meissner effect (TME) in the highly layered superconductor Bi2Sr2CaCu2O(8+y) with columnar defects is investigated by transport measurements. We present detailed evidence for the persistence of the Bose-glass phase when H is tilted at an angle theta \theta_c+, moving kink chains consistent with a commensurate-incommensurate transition scenario are observed. These results thereby clearly show the existence of the TME for theta < theta_c(T).

Current-voltage characteristics are investigated in Bi2Sr2Ca1-xYxCu2O8 crystals irradiated parallel to the c-axis with 5.8 GeV Pb ions. Over a wide range of filling fractions 0.026 ≤ f ≤ 1, I–V isotherm curves near the superconducting transition are consistent with the Bose-glass scaling theory. The Bose glass line, derived from scaling analysis, is well described by the Lindemann criterion which accounts for the contribution of correlated disorder. Two characteristic temperatures t0≈0.72 (f≈0.8) and t1≈0.83 (f≈ 1 3 ), beyond which the vortex system is increasingly dominated by vortex-vortex interactions or thermal fluctuations, respectively, are identified.

Current-voltage characteristics are investigated in BiSr2CaCu2O8 single crystals irradiated parallel to the c-axis with 5.8 GeV Pb ions. For weak magnetic field (B

Current–voltage characteristics are investigated in BiSr 2 Ca 1− x Y x Cu 2 O 8 crystals irradiated parallel to the c -axis with 5.8 GeV Pb ions. Over a wide range of filling fractions 0.026≤ f ≤1, the I – V isotherm curves near the superconducting transition are consistent with the Bose-glass scaling theory. Field and matching field independent critical exponent values z ′=5.27±0.05 and ν ′=1.30±0.07 have been found. This result is in good agreement with the well-established universality rules for the critical exponents at standard second-order transition. The glass line, derived from scaling analysis, is well described by the Lindemann criterion that accounts for the contribution of correlated disorder. Two characteristic temperatures, beyond which the vortex system is increasingly dominated by vortex–vortex interactions or thermal fluctuations, respectively, are identified. In these domains, the Bose-glass melting line merges the pristine melting line.

We report on transport measurements in a Bi-2212 single crystal with columnar defects parallel to the c-axis. The tilt of the magnetic field away from the direction of the tracks is studied for filling factors f=B_z/B_phi, 2 pages LaTeX, 2 EPS figures, uses fleqn and espcrc2 style macros. Submitted to Proceedings of M2S-HTSC-VI