Magnetic properties of nanoscale crystalline maghemite obtained by a new synthetic route

AbstractIn this work we describe the synthesis and characterization of maghemite nanoparticles obtained by a new synthetic route. The material was synthesized using triethylamine as a coprecipitation agent in the presence of the organic ligand N,N′-bis(3,5-di-tert-butyl-catechol)-2,4-diaminotoluene (LCH3). Mössbauer spectrum at 4K shows typical hyperfine parameters of maghemite and Transmission Electron Microscopy images reveal that the nanoparticles have a mean diameter of 3.9nm and a narrow size distribution. AC magnetic susceptibility in zero field presents an Arrhenius behavior with unreasonable relaxation parameters due to the strong influence of dipolar interaction. In contrast when the measurements are performed in a 1kOe field, the effect of dipolar interactions becomes negligible and the obtained parameters are in good agreement with the static magnetic properties. The dynamic energy barrier obtained from the AC susceptibility results is larger than the expected from the average size observed by HRTEM results, evidencing the strong influence of the surface contribution to the anisotropy

Physical exercise on inflammatory markers in type 2 diabetes patients: a systematic review of randomized controlled trials

Background. Type 2 diabetes mellitus (T2DM) is a serious disease associated with high morbidity and mortality. Scientific findings showed that physical exercise is an option for treatment of these patients. This study's objective is to investigate the effects of supervised aerobic and/or resistance physical training on inflammatory markers in subjects with T2DM. Methods. A systematic review was conducted on four databases, MEDLINE, CENTRAL, LILACS, and Scopus, and manual search from 21 to 30 November 2016. Randomized clinical trials involving individuals diagnosed with T2DM, who have undergone supervised training protocols, were selected in this study. Results. Eleven studies were included. Studies that evaluated control group versus aerobic exercise reported controversial results about the effectiveness of physical training in modifying C-reactive protein (CRP) and cytokine levels. The only variable analyzed by the six studies in comparison to the control group versus resistance exercise was CRP. This protein showed no significant difference between groups. Between the two modes of exercise (aerobic and resistance), only one study demonstrated that aerobic exercise was more effective in reducing CRP. Conclusion. The evidence was insufficient to prove that aerobic or resistance exercise improves systemic levels of inflammatory markers in patients with T2DM

Transition Form Factors between Pseudoscalar and Vector Mesons in Light-Front Dynamics

We study the transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing the light-front calculation in the $q^+ =0$ frame in parallel with the manifestly covariant calculation, we note that the suspected nonvanishing zero-mode contribution to the light-front current $J^+$ does not exist in our analysis of transition form factors. We also perform the light-front calculation in a purely longitudinal $q^+ > 0$ frame and confirm that the form factors obtained directly from the timelike region are identical to the ones obtained by the analytic continuation from the spacelike region. Our results for the $B \to D^* l \nu_l$ decay process satisfy the constraints on the heavy-to-heavy semileptonic decays imposed by the flavor independence in the heavy quark limit.Comment: 20 pages, 14 figure

The Presence of Flavonoids in Some Products and Fruits of the Genus Eugenia: An Integrative Review

ReviewThe Myrtaceae family, one of the most prominent botanical families, is represented in Brazil with different fruit species, rich in bioactive compounds and gastronomically appreciated. This study aimed to carry out an integrative review on the genus Eugenia, highlighting the pitangueira (E. uniflora L.), cagaiteira (E. dysenterica), grumixameira (E. brasiliensis), pereira (E. klotzschiana O. Berg), and uvaieira (E. pyriformis Cambess) and which flavonoids are present in these fruits. Articles published between 2016 and 2021 were selected from the following databases: Google Scholar, Periódicos CAPES, Scielo, and Science Direct. According to each database, the descriptors used as a search strategy addressed the popular and scientific names of the five selected species, associated or not with the term “flavonoid,” according to each database. The results showed that quercetin was the main flavonoid identified in the fruits, and the principal extraction method used was HPLC. Other interesting compounds, such as catechin, epicatechin, rutin, myricetin, and kaempferol, were also found. However, the amount and type of flavonoids detected varied according to the applied methodology. Hence, these studies highlight the importance of species of the genus Eugenia, which promotes beneficial health effects and possible applicability to the food and pharmaceutical industryinfo:eu-repo/semantics/publishedVersio

Hysteretic giant magnetoimpedance effect analyzed by first-order reversal curves

Hysteretic giant magnetoimpedance (GMI) of amorphous ribbons with a well-defined transversal domain structure is investigated by means of first-order reversal curves (FORC) analysis. The FORCs are not confined to the hysteretic area, exceeding the major curve amplitude. Irreversible switches of the transverse permeability, caused by domain wall structure transitions, may be the origin of the observed FORC distribution. An interlinked hysteron/anti-hysteron model is proposed to interpret it, which allows analyzing the influence of frequency and magnetostriction upon the hysteretic GMI effect.Comment: 19 pages, 9 figure