Interaction Of Me Research Articles

The effects of polystyrene microparticles on the environmental availability and bioavailability of As, Cd and Hg in soil for the land snail Cantareus aspersus

The combined contamination of terrestrial environments by metal(loid)s (MEs) and microplastics (MPs) is a major environmental issue. Once MPs enter soils, they can interact with MEs and modify their environmental availability, environmental bioavailability, and potential toxic effects on biota. Although research efforts have been made to describe the underlying mechanisms driving MP and ME interactions, the effects of MPs on ME bioavailability in terrestrial Mollusca have not yet been documented. To fill this gap, we exposed the terrestrial snail Cantareus aspersus to different combinations of polystyrene (PS) and arsenic (As), cadmium (Cd), or mercury (Hg) concentrations. Using kinetic approaches, we then assessed the variations in the environmental availability of As, Cd or Hg after three weeks of equilibration and in the environmental bioavailability of As, Cd or Hg to snails after four weeks of exposure. We showed that while environmental availability was influenced by the total ME concentration, the effects of PS were limited. Although an increase in As availability was observed for the highest exposure concentrations at the beginning of the experiment, the soil ageing processes led to rapid adsorption in the soil regardless of the PS particle concentration. Concerning transfers to snail, ME bioaccumulation was ME concentration-dependent but not modified by the PS concentration in the soils. Nevertheless, the kinetic approaches evidenced an increase in As (2- to 2.6-fold) and Cd (1.6-fold), but not Hg, environmental bioavailability or excretion (2.3- to 3.6-fold for As, 1.8-fold for Cd) at low PS concentrations. However, these impacts were no longer observable at the highest PS exposure concentrations because of the increase in the bioaccessibility of MEs in the snail digestive tract. The generalization of such hormetic responses and the identification of the precise mechanisms involved necessitate further research to deepen our understanding of the MP-mediated behaviour of MEs in co-occurring scenarios.

МАГНИТОЭЛЕКТРИЧЕСКИЕ ЭФФЕКТЫ И НОВЫЕ ЛОГИЧЕСКИЕ УСТРОЙСТВА СПИНТРОНИКИ

The paper discusses new logic spintronic devices and the prospects for the use of perovskite-type multiferroics as working elements of magnetoelectric components. The principle of operation of the considered logical devices is based on the use of two components - a magnetoelectric, in which the magnetic state is recorded due to energy-efficient magnetoelectric interaction, and a spin-orbital component, in which information is read out based on the conversion of spin into charge due to the spin-orbital interaction of electrons; both components are interconnected by a nanoelectrode. When designing new logic spintronic devices, it is necessary to take into account the effectiveness of the mechanisms of ME interactions; features of spin - polarized currents and associated torques influencing magnetic moments; as well as other factors affecting the speed of switching magnetic states and the sensitivity of the device to external agents. Multiferroic materials that are promising for use as elements of ME components of new logic devices must meet a number of requirements, the most significant of which are the magnitude of the magnetoelectric coupling coefficient and the temperature at which ME effects occur. The paper considers representatives of multiferroics with a perovskite structure that meet these conditions, to some extent partially, these are high-temperature multiferroic bismuth ferrite (BiFeO3) and Ruddlesden-Popper structures, in which high-temperature ferroelectric effects are already realized and under certain conditions an ME effect is possible. The crystal structure of these compounds is considered, and the role of crystallographic distortions responsible for the manifestation of magnetoelectric properties is analyzed. Expressions are obtained for the tensor of the magnetoelectric effect as functions of magnetic order parameters, and the fundamental possibility of realizing ME effects in Ruddlesden-Popper structures containing magnetic cations is shown.

Теория квазистатического магнитоэлектрического взаимодействия в трехслойных асимметричных пьезомагнитострикционных структурах

The work is devoted to the theoretical investigation of the quasi-static magnetoelectric interaction in three-layer structures consisting of a piezoelectric and two magnetic layers with positive and negative magnetostriction. Using the system of elasto- and electrostatics equations for the piezoelectric and magnetostrictive phases, expressions for the electrical response of the structure in a magnetic field are obtained. The contributions from longitudinal and bending deformations are taken into account in value of ME interactions. It is shown that the use of an asymmetric three-layer asymmetric structure leads to an increase in the magnitude of the ME interaction by almost an order of magnitude compared to a two-layer structure. The dependences of the effect magnitude on the thickness of the third layer for the nickel/lead zirconate titanate/metglas structure are presented.

Theory of quasi-static magnetoelectric interaction in three-layer asymmetric piezomagnetostrictive structures

The work is devoted to the theoretical investigation of the quasi-static magnetoelectric interaction in three-layer structures consisting of a piezoelectric and two magnetic layers with positive and negative magnetostriction. Using the system of elasto- and electrostatics equations for the piezoelectric and magnetostrictive phases, expressions for the electrical response of the structure in a magnetic field are obtained. The contributions from longitudinal and bending deformations are taken into account in value of ME interactions. It is shown that the use of an asymmetric three-layer asymmetric structure leads to an increase in the magnitude of the ME interaction by almost an order of magnitude compared to a two-layer structure. The dependences of the effect magnitude on the thickness of the third layer for the nickel/lead zirconate titanate/metglas structure are presented. Keywords: piezomagnetostrictive composites, magnetostriction, piezoelectricity, magnetoelectric effect, gyrator, harvester.

Disentangling the power transfer process by non-contact optical measurement in nickel-zinc ferrite/piezoelectric magnetoelectric gyrators

To precisely position the main energy dissipation sources in ferrite/piezoelectric ME-coil gyrators, the dynamic magneto-mechanical-electric conversion process was disentangled quantitatively by employing a non-contact optical measurement methodology. For the sample fabrication, successful crystallization as well as desired magnetic properties for sintered spinel ferrites was confirmed by XRD and SQUIDs measurements. Trapped magnetic energies in ferrites will convert into kinetic energies accompanying indispensable dissipations in this dynamic process, and the converted kinetic energies can be measured quantitatively in the form of vibrating velocity by focused laser beam. As a result, only ~71% of mechanical energies can be transferred successfully to next layer due to the influence of adhesive in tri-layer sample while the value is 57% for bi-layer one. Finally, comparative studies of low-frequency/resonance ME interactions and power conversion efficiency in tri-layer and bi-layer samples were measured, and an eventual maximum PE of 80.3% under optimum load of 3.5 kΩ was achieved. We infer from the results that the mechanical loss between layers is still a bottleneck to block the efficient energy transfer. These findings provide a deep analysis to reveal the dynamic energy transfer in ME-coil gyrators as well as a flexible pathway for ME gyrators design.

Observation of magnetoelectric coupling in BiFeO3-(Pb(Mg1/3Nb2/3)O3-PbTiO3) composites

We investigated structural, magnetic and ferroelectric properties and magnetoelectric effect in bulk and nano composites of BiFeO3/PMN-PT. Scanning electron microscopy shows that BiFeO3 and PMN-PT phases makes solid solution in bulk composites while asymmetric grain growth was observed in nano composites. The nano composites show improved ferroelectric properties with well saturated hysteresis loops with saturation polarization (2Ps) ~23.5µCcm−2. The magneto electric effect in nanocomposites was revealed by measuring the magnetic hysteresis loops of the same sample before and after electric poling. Magnetization results demonstrate exchange bias phenomenon in the poled composite sample. The observed ME interactions and exchange biasing makes these composites possible candidates for spintronics and sensor applications.

Performance and body composition of light and heavy early-weaning piglets subject to different dietary energy levels

This study aimed to evaluate the effects of dietary metabolizable energy (ME; 3.40, 3.60, or 3.80Mcal/kg) and weaning weight (WW; 4.5±0.4 and 6.7±0.5kg) on growth performance, body composition, and energy utilization in early-weanling piglets. The diet with 3.40 Mcal/kg was formulated based on standard energy and nutrient recommendations in Brazil, and amino acids, Ca, P, and lactose levels in diets containing 3.60 and 3.80Mcal/kg were adjusted for the increased ME to maintain constant nutrient to ME ratios. Thirty-two male piglets were housed in metabolic cages individually for 28d in a 2×3 factorial arrangement of treatments with 5 barrows per treatment, except light and 3.8 ME and heavy and 3.4ME/kg treatments, which had 6 barrows per treatment. Body composition, nutrient deposition rates, and energy efficiency were measured through a comparative slaughter procedure. There were no WW×ME interactions for any of the response criteria. Heavy piglets had 15% greater average feed intake, 16% average daily gain, and 19% body weight on d 28 than the light piglets (P=0.021), but there was no effect of WW on energy and nutrient digestibility. Dietary ME content did not affect growth performance, but increased digestibility of dry matter, gross energy, and crude protein (P<0.001). Heavy piglets had greater carcass weight (20%) and empty body weight (18%) than the light piglets (P<0.001). Energy efficiency was not influenced by WW or dietary ME content. Heavy piglets at weaning consumed more ME (P<0.022) and had greater body protein accretion in the carcass and empty body weight (P<0.05), but fat deposition was not affected. There was no interaction between WW and ME content of post-weaning diets, and increasing dietary energy level did not affect the post-weaning performance of light piglets at weaning. The results of this study did not support the hypothesis that light piglets at weaning do not exhibit compensatory growth because of limitations in energy and nutrient intake.

유색육용계의 성장과 혈액성상에 사료단백질 및 에너지가 미치는 영향

To acquire essentially necessary basic data to establish feeding system by verifying appropriate dietary energy and protein level for the growth of commercial slow growing broiler chicks within the country, two experiments were conducted for 5 weeks. One day old, 1,404 male and female broiler chicks were used for the experiments, and 26 chicks were placed at each pen. The energy level of feed was maintained about 3,000 or 3,100 kg/kcal for whole breeding period of 5 weeks, and protein content was adjusted about 20, 21, and 22% during the first two weeks and the content was adjusted to 18, 19, 20, 21, and 22% from the 3 to 5 weeks old of the experiment. The categories of body weight and feed intake amount were monitored to calculate the productivity and blood sampling was conducted for the analysis at the end of each experiment. Experiment 1:Although the productivity by the ME content difference during 0~2 weeks did not have significant difference and the body weight increase by the difference of CP content and feed intake amount did not have much difference, the feed requirement rate was statistically improved in CP 21 and 22% treatment groups compared to the CP 20% group (P<0.05). The feed ME 3,100 kcal/kg treated group during 3~5 weeks after starting the experiment revealed to show improved feed requirement rate (P<0.05). Within the period of experiment, the CP 22% treated group resulted to show significant body weight increase compared to the groups treated with low levels of CP (P<0.05) and the feed requirement rate was improved in high CP treated group compared to low CP treated groups, but the feed intake amount did not show significant difference between treated groups. During the experiment period, the body weight increase and feed requirement rate revealed to interact between ME and CP (P<0.05). During the whole experiment period of the 5 weeks, the feed requirement rate was improved in ME 3,100 kcal/kg treated group than the groups treated with ME 3,000 kcal/kg, and the CP (20) 18% treatment groups resulted to show higher values than other treatment groups (P<0.05). Body weight increase was high in CP (22) 22% treated groups than those of CP (21) 21% and (20) 18% treated groups, and the interaction between ME and CP was found at body weight increase and feed requirement rate (P<0.05). Although blood albumin and total cholesterol levels were elevated in ME 3,100 kcal/kg treated group than ME 3,000 kcal/kg treated group, but neutral fat content was reduced (P<0.05). On the other hand, the total cholesterol content was increased in CP (22) 21% treated group than CP (22) 20% and CP (20) 18% treated groups (P<0.05). Experiment 2: The body weight increase in 0-2 weeks was higher in ME 3,100 kcal/kg treated group than ME 3,000 kcal/kg treated group, and it was highly improved in CP 22% treated group than CP 20% treated group by showing the interaction between CP and ME (P<0.05). The significant improvement of feed requirement rate was observed in CP 21% and 22% treated groups compared to CP 20% treated group (P<0.05). The productivity between the growth period from 3 to 5 weeks of age and whole growth period resulted to show no significant difference. Although no difference was observed in blood composition between treated groups, the interaction of ME and CP on cholesterol content was accepted at the range of P<0.05). Therefore, it is considered that the appropriate dietary protein level within feed for the physiology of growing broiler chicks was 22% or more for the first two weeks and protein level of 21% or 20% from 3 to 5 weeks old for the maximization of productivity. Even if the energy level within feed had some partial effects on the productivity, but did not show consistency. So, further experiments needto be conducted by differentiating the energy level.

The response of Japanese quails (heavy body weight line) to dietary energy levels and graded essential amino acid levels on growth performance and immuno-competence

The response of growing quails ( n = 900, divided into 36 subgroups) to dietary levels of essential amino acids (EAA) at different energy levels on growth and immunity was investigated. Nine diets including three levels of metabolizable energy (ME, 11.30, 12.13 and 12.97 MJ ME kg − 1 ) each at three levels of EAA (low, medium and high) in a 3 × 3 factorial design were formulated. Each diet was offered to 4 replicated groups up to 5 weeks of age. The ratio of lysine to protein and the level of methionine and threonine to lysine remained almost similar in all the diets as specified by NRC [NRC, 1994. Pages 44–45 in Nutrients requirements of poultry. 8th ed. Natl. Acad. Press, Washington, DC.]. Body weight gain, feed intake and feed conversion ratio did not differ statistically due to the treatments i.e. interaction of ME and EAA levels. However, there was linear increase in body weight gain with increased EAA levels during 0–3 or 0–5 weeks of age. Feed intake increased linearly with the decreased ME ( P < <0.01) and increased EAA ( P < 0.01) in diets. Feed conversion ratio (FCR) improved ( P < 0.01) linearly with increase in dietary ME concentration from 0–3 or 0–5 weeks of age. FCR and energy efficiency improved in diets with medium and high levels of EAA during 0–3 weeks, while it did not differ during 0–5 weeks of age. Protein efficiency (PE) improved linearly ( P < 0.01) with decreased EAA levels during 0–3 or 0–5 weeks of age, and also with the increase in dietary ME level during 0–5 weeks growth phase. Nitrogen retention per unit energy intake was significantly higher in diet containing 12.97 MJ ME kg − 1 with high level of EAA. Humoral (SRBC) and cellular (PHA-P) immune response and yield of immune organs did not differ due to ME, EAA or ME x EAA. Therefore, it can be concluded that the optimum level of dietary ME is 11.30 MJ kg − 1 with CP 25.83%, lysine 1.49%, methionine 0.58% and threonine 1.17% on dry matter basis during 0–5 weeks of age for gain. However for optimum feed conversion, the growing quails require diet with ME 12.97 MJ kg − 1 with CP 23.23%, lysine 1.30%, methionine 0.50% and threonine 1.02% for 0–5 weeks of age.

FERROMAGNETIC-FERROELECTRIC LAYERED STRUCTURES: MAGNETOELECTRIC INTERACTIONS AND DEVICES

ASTRACT Layered magnetostrictive/piezoelectric structures are multifunctional due to their response to mechanical and electromagnetic forces. Investigations at 10 Hz–10 GHz on oxide heterostructures reveal evidence for strong ME interactions. Systems studied include nickel ferrite-lead zirconate titanate (PZT) and yttrium iron garnet (YIG)-lead magnesium nioate/lead titanate (PMN-PT). Our efforts have resulted in: (i) the oservation of a giant low frequency ME effect in nickel ferrite-PZT; (ii) oservation and theory of ME coupling at electromechanical resonance (EMR) for the composite; and (iii) theory and measurements of microwave ME effects in YIG/PMN-PT, at ferromagnetic resonance for YIG. The composites are potential candidates for smart sensors and signal processing devices, such as electric field tunale filters and phase shifters.