The hematological parameters and metallothionein (MT) levels in the liver, kidney and muscles were measured in bullfrog tadpoles, Lithobates catesbeianus, following exposures to 1 μg L−1 of zinc ...(Zn), copper (Cu) and cadmium (Cd) alone or in combination (1:1 and 1:1:1) for 2 and 16 days. Metal accumulation occurred in all organs, with the highest values found in the kidney, followed by the muscles and liver. After exposure to isolated metals, the accumulation was in the following order: Cd > Zn > Cu in the liver and muscles and Cd > Cu > Zn in the kidney. Exposure to combined metals (Zn + Cu, Zn + Cd, Cu + Cd and Zn + Cu + Cd) revealed complex responses, such as metal accumulation increased or decreased over the exposure periods, suggesting possible competion at the uptake sites and/or metabolization and elimination processes in each organ. The MT concentration increased in the organs of tadpoles following metal exposure alone, mainly in the liver, for both periods. After the combined exposures, the MT levels were higher in the liver and muscles at 16 days, suggesting that the interaction between metals was additive, and the level was decreased in the kidney after 2 and 16 days of exposure. The whole blood hemoglobin content (Hb), red blood cell count (RBCs) and mean corpuscular hemoglobin (MCH) differed from the control groups after 2 and 16 days of exposure, showing changes in the improvement of oxygen transport. The number of lymphocytes increased, and the levels of neutrophils, eosinophils, basophils and monocytes were reduced after exposure to the metals. The changes in blood cells suggested that tadpoles have a mechanism to improve oxygen transport probably because of the increased oxygen demand and a general reduction in defense cells. The exposure of L. catesbeianus to metals during the larval phase can generate long-term dysfunction to a degree, which could lead to alterations in their health status.
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•Metal accumulation occurred in all tissues.•Metallothionein levels in tissues were higher after the exposure to the combined metals.•Zinc, copper and cadmium either alone or combined affect blood parameters.
Zinc, copper and cadmium, either alone or combined, affect the blood parameters and accumulate in the liver, kidney and muscle, changing the metallothionein levels of bullfrog tadpoles.
Summary
Together with their sister subspecies Bos taurus, zebu cattle (Bos indicus) have contributed to important socioeconomic changes that have shaped modern civilizations. Zebu cattle were ...domesticated in the Indus Valley 8000 years before present (YBP). From the domestication site, they expanded to Africa, East Asia, southwestern Asia and Europe between 4000 and 1300 YBP, intercrossing with B. taurus to form clinal variations of zebu ancestry across the landmass of Afro‐Eurasia. In the past 150 years, zebu cattle reached the Americas and Oceania, where they have contributed to the prosperity of emerging economies. The zebu genome is characterized by two mitochondrial haplogroups (I1 and I2), one Y chromosome haplogroup (Y3) and three major autosomal ancestral groups (Indian‐Pakistani, African and Chinese). Phenotypically, zebu animals are recognized by their hump, large ears and excess skin. They are rustic, resilient to parasites and capable of bearing the hot and humid climates of the tropics. Many resources are available to study the zebu genome, including commercial arrays of SNP, reference assemblies and publicly available genotypes and whole‐genome sequences. Nevertheless, many of these resources were initially developed to support research and subsidize industrial applications in B. taurus, and therefore they can produce bias in data analysis. The combination of genomics with precision agriculture holds great promise for the identification of genetic variants affecting economically important traits such as tick resistance and heat tolerance, which were naturally selected for millennia and played a major role in the evolution of B. indicus cattle.
Reference database for photon strength functions Goriely, S.; Dimitriou, P.; Wiedeking, M. ...
European physical journal. A, Hadrons and nuclei,
10/2019, Letnik:
55, Številka:
10
Journal Article
Recenzirano
Odprti dostop
.
Photon strength functions describing the average response of the nucleus to an electromagnetic probe are key input information in the theoretical modelling of nuclear reactions. Consequently they ...are important for a wide range of fields such as nuclear structure, nuclear astrophysics, medical isotope production, fission and fusion reactor technologies. They are also sources of information for widely used reaction libraries such as the IAEA Reference Input Parameter Library and evaluated data files such as EGAF. In the past two decades, the amount of reaction gamma-ray data measured to determine photon strength functions has grown rapidly. Different experimental techniques have led to discrepant results and users are faced with the dilemma of which (if any) of the divergent data to adopt. We report on a coordinated effort to compile and assess the existing experimental data on photon strength functions from the giant dipole resonance region to energies below the neutron separation energy. The assessment of the discrepant data at energies around or below the neutron separation energy has been possible only in a few cases where adequate information on the model-dependent analysis and estimation of uncertainties was available. In the giant dipole resonance region, we adopt the recommendations of the new IAEA photonuclear data library. We also present global empirical and semi-microscopic models that describe the photon strength functions in the entire energy region and reproduce reasonably well most of the experimental data. The compiled experimental photon strengths and recommended model calculations are available from the PSF database hosted at the IAEA (
http://www-nds.iaea.org/PSFdatabase
).
The recrystallization and texture evolution of four Mg–Zn–Ce sheets with a warm-rolled microstructure obtained through two stages that can be characterised as rough rolling and finish rolling were ...investigated at different stages of post-rolling annealing. On annealing, the same regions of the microstructure, located by hardness indentations, were examined and tracked by electron backscatter diffraction (EBSD). Furthermore, intragranular misorientation axes (IGMA) analysis was used to investigate the associated deformation mechanisms in the as-deformed material. By combining these two methods, the development of the recrystallization microstructure was investigated and important aspects, such as preferential nucleation sites, correlation between activated deformation mechanism and initial orientation of the recrystallized grains, were studied. The results showed that the Mg–1Zn–1Ce alloy, which had the highest Ce/Zn ratio, showed the weakest as-rolled texture and the most homogenous distribution of shear banding/twinning. The IGMA analysis also showed that in Mg–1Zn–1Ce, other types of dislocations rather than basal 〈a〉 were activated; in particular, prismatic 〈a〉 type was activated during deformation. Therefore, the weakening of recrystallization texture during rolling resulting from the addition of RE elements was linked with a change in dynamic recrystallization (DRX) behaviour. Since the Mg–1Zn–1Ce alloy corresponds to the highest level of Ce in solid solution, the observed texture weakening was possibly due to decreasing grain boundary mobility as a result of solute partitioning of RE elements to dislocations and grain boundaries.
This study investigated the activity of lactated dehydrogenase (LDH), malate dehydrogenase (MDH) enzymes and the levels of glucose, protein and triglyceride in bullfrog tadpoles after exposure to ...1 μg L−1 of zinc (Zn), copper (Cu) and cadmium (Cd) isolated and combined for 2 and 16 days. Zn, Cu + Cd and Zn + Cu + Cd increased the activity of the LDH (2 and 16 days) and MDH (2 days) enzymes in the liver; and MDH increased in the kidney after 16 days in all co-exposed groups compared to the control. Glucose increased in the liver in the Zn and Cu groups at 2 and 16 days of exposure and decreased in the kidney (groups Cd, Zn + Cd and Cu + Cd) and muscle (Cd) at 2 days of exposure. After 2 days of exposure, the protein increased in the liver (Zn), in the kidney in all groups exposed to metals except in the groups exposed to Cd and Zn + Cu + Cd, which did not change and decreased in muscle in all the groups exposed to isolated metals. Regarding triglycerides, the kidney and muscle were the most affected, leading to a decrease in the Zn, Cu and Cd groups and in the Zn + Cu (16 days) and Zn + Cu + Cd groups (2 days). The anaerobiosis and aerobiosis were activated in the liver and kidney after short-term exposure (2 days) and in the kidney, the aerobic metabolism was activated after chronic exposure (16 days). The metals caused toxicity and were higher in co-exposure to metals with a potential to cause metabolism damage in L. catesbeianus.
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•Cu, Zn and Cd alone or combined cause metabolic alterations in tadpoles.•Enzyme activities were affected by Cu, Zn and Cd exposure alone or combined.•Metabolites were increased following metal co-exposure.
A novel intense plastic straining process named accumulative roll-bonding (ARB) is proposed. First, a strip is neatly placed on top of another strip. The two layers of material are joined together by ...rolling like a roll-bonding process. Then, the length of rolled material is sectioned into two halves. The sectioned strips are again stacked and roll-bonded. The whole process is repeated again and again. The process can introduce ultra-high plastic strain without any geometrical change if the reduction in thickness is maintained to 50% every rolling pass. The process has been applied to commercial aluminum (1100), Al–Mg alloy (5083) and interstitial free (IF) steel. Well-bonded bulk materials were successfully obtained. After several cycles of ARB, ultra-fine (sub-micron) grain structure with large misorientations, i.e. polycrystal, was formed and the materials were strengthened dramatically.
The photoneutron cross sections of 162,163Dy have been measured for the first time in an energy region from the neutron threshold (Sn) up to ≈13MeV. The (γ,n) reaction was induced with ...quasimonochromatic laser Compton-scattered γ rays, produced at the NewSUBARU laboratory. The corresponding γ -ray strength functions (γ SF) have been calculated from the photoneutron cross sections. The data are compared to reanalyzed γSFs of 160–164Dy, which are measured below Sn. The excellent agreement with the photoneutron data at Sn confirms the principle of detailed balance. Thus, a complete γ SF is established covering in total the energy regionof1 Eγ 13MeV.Thesemid-shellwell-deformeddysprosiumisotopesallshowscissorsresonances with very similar structures. We find that our data predict the same integrated scissors strength as (γ,γ′) data when integrated over the same energy range, which shows that the scissors mode very likely is consistent with the generalized Brink hypothesis. Finally, using the γSFs as input in the reaction code TALYS, we have deduced radiative neutron-capture cross sections and compared them to direct measurements. We find a very good agreement within the uncertainties, which gives further support to the experimentally determined γ SFs.
In the first part of this two-part paper, the effect of increasing Ce in solid solution on the recrystallization and texture evolution of four Mg–Zn–Ce sheets was investigated in the as-deformed and ...annealed state. In this second part, the effect of rolling speed on the microstructure and texture development of these alloys is evaluated. The effect of rolling speed on the recrystallization and texture evolution of four Mg–Zn–Ce sheets was investigated at as-deformed and different stages of annealing. The deformation microstructure was obtained through two stages that can be characterised as rough rolling and finish rolling. To study the effect of finish rolling temperature, one rolling pass with a 65 % reduction in thickness was performed at 300 and 450 °C and at rolling speeds of 15 and 1000 m/min. The results showed that by increasing the rolling speed, more secondary and compression twins were activated, which leads to the formation of more numerous local shear bands and a more uniform microstructure. Annealing secondary twins (S-twins) and their vicinity were observed to be the preferential sites for nucleation, and it seems that recrystallization on S-twins contributes to basal texture weakening. Therefore, an increasing number of such twins increase the texture weakening. In this way, the combination of these RE additions and HSR resulted in a weaker deformed and annealed texture.
Magnesium AZ31 alloy sheets were rolled at a high (1000m/min) and a low (15m/min) rolling speed. The microstructure and texture evolution were tracked using optical microscopy, X-ray diffraction ...(XRD), scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) techniques. At 100°C, a total reduction of 72% was achieved in one pass at the high rolling speed, while the sheet fractured at a reduction of only 37% during low speed rolling. In the former case, dynamic recrystallization was observed to be well under way at a reduction of 49% and full recrystallization was achieved at a reduction of 72%. For a given reduction, the maximum intensity of the basal texture is weaker after high speed rolling than after low speed rolling. The far better rollability achieved during high speed rolling is attributed to the activation of <c+a> slip and dynamic recrystallization at the higher temperatures developed; the weaker texture is due to the activation of a larger number of twinning and slip systems.
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