Mn Se Research Articles

Comparative Evaluation of Antioxidant Status and Mineral Composition of Diploschistes ocellatus, Calvatia candida (rostk.) Hollós, Battarrea phalloides and Artemisia lerchiana in Conditions of High Soil Salinity

Natural reserves play a fundamental role in maintaining flora and fauna biodiversity, but the biochemical characteristics of such ecosystems have been studied in an extremely fragmentary way. For the first time, mineral composition and antioxidant status of three systematic groups of organisms, lichens (Diplischistes ocellatus), mushrooms (Calvatia candida and Battarrea phalloides) and wormwood (Artemisia lerchiana) have been described at the territory of Bogdinsko-Baskunchak Nature Reserve (Astrakhan region, Russia), characterized by high salinity and solar radiation, and water deficiency. Through ICP-MS, it was determined that scale lichen D. ocellatus accumulated up to 10–15% Ca, 0.5% Fe, 15 mg kg−1 d.w. iodine (I), 54.5 mg kg−1 Cr. Battarrea phalloides demonstrated anomalously high concentrations of B, Cu, Fe, Mn Se, Zn, Sr and low Na levels, contrary to Calvatia candida mushrooms accumulating up to 10,850 mg kg−1 Na and only 3 mg kg−1 Sr. The peculiarity of A. lerchiana plants was the high accumulation of B (22.23 mg kg−1 d.w.), Mn (57.48 mg kg−1 d.w.), and antioxidants (total antioxidant activity: 68.6 mg GAE g−1 d.w.; polyphenols: 21.0 mg GAE g−1 d.w.; and proline: 5.45 mg g−1 d.w.). Diploschistes ocellatus and Calvatia candida demonstrated the lowest antioxidant status: 3.6–3.8 mg GAE g−1 d.w. total antioxidant activity, 1.73–2.10 mg GAE g−1 d.w. polyphenols and 2.0–5.3 mg g−1 d.w. proline. Overall, according to the elemental analysis of lichen from Baskunchak Nature Reserve compared to the Southern Crimean seashore, the vicinity of Baskunchak Salty Lake elicited increased environmental levels of Cr, Si, Li, Fe, Co, Ni and Ca.

Superexchange Interactions and Magnetic Anisotropy in MnPSe3 Monolayer

Two-dimensional van der Waals magnetic materials are of great current interest for their promising applications in spintronics. Using density functional theory calculations in combination with the maximally localized Wannier functions method and the magnetic anisotropy analyses, we study the electronic and magnetic properties of MnPSe3 monolayer. Our results show that it is a charge transfer antiferromagnetic (AF) insulator. For this Mn2+ 3d 5 system, although it seems straightforward to explain the AF ground state using the direct exchange, we find that the nearly 90° Mn–Se–Mn charge transfer type superexchange plays a dominant role in stabilizing the AF ground state. Moreover, our results indicate that, although the shape anisotropy favors an out-of-plane spin orientation, the spin-orbit coupling (SOC) leads to the experimentally observed in-plane spin orientation. We prove that the actual dominant contribution to the magnetic anisotropy comes from the second-order perturbation of the SOC, by analyzing its distribution over the reciprocal space. Using the AF exchange and anisotropy parameters obtained from our calculations, our Monte Carlo simulations give the Néel temperature T N = 47 K for MnPSe3 monolayer, which agrees with the experimental 40 K. Furthermore, our calculations show that under a uniaxial tensile (compressive) strain, Néel vector would be parallel (perpendicular) to the strain direction, which well reproduces the recent experiments. We also predict that T N would be increased by a compressive strain.

Enhanced thermoelectric properties and electrical stability for Cu1.8S-based alloys: Entropy engineering and Cu vacancy engineering

Cu1.8S-based thermoelectric (TE) materials have garnered considerable interest due to their pollution-free, low-cost, and superior performance characteristics. However, high Cu vacancy and Cu migration inhibit their performance and electrical stability improvement. Through mechanical alloying and spark plasma sintering, a series of Cu1.8S and MnxCu1.8-S0.5Se0.5 (0.01 ≤ x ≤ 0.06) bulk samples were prepared in this study. With Se alloying and Mn doping, the configuration entropy of MnxCu1.8S0.5Se0.5 increases from low-entropy 0.4R* for pristine Cu1.8S to medium-entropy 1.2R* for MnxCu1.8S0.5-Se0.5. MnxCu1.8S0.5Se0.5 subsequently crystallized in a cubic phase with enhanced symmetry and Mn solid solubility. High solubility enables the filling of excessive Cu vacancies, the reduction of carrier concentration, the adjustment of band structure, the enhancement of the Cu migration energy barrier, and the inhibition of Cu migration. Even at current densities exceeding 25 A cm−2 at 750 K, the resistance of Mn0.03Cu1.8S0.5Se0.5 remained hardly changed, indicating a vastly improved electrical stability. In addition, the ultralow thermal conductivity of the lattice is achieved by decreasing the sound velocity and softening the lattice. At 773 K, the bulk ZT of Mn0.06Cu1.8S0.5Se0.5 reaches a maximum of 0.79, which is twice that of pure Cu1.8S. The results indicate that combining entropy engineering and Cu vacancy engineering is an effective strategy for developing high-performance Cu1.8S TE materials.

Paramagnetic Semiconducting Se–Mn Clusters: A Mn3Se4-Stabilized Selenide Radical Intermediate and Its Aggregated Derivatives

The transition metal-stabilized heavy main group radicals are extremely scarce due to their highly reactive natures, making them difficult to be isolated and identified. We report here a rare class of the Se radical-containing manganese carbonyl anionic cluster, [(μ-Se)(μ3-Se2)2Mn3(CO)9]•2- (1), which was successfully obtained from the one-pot reaction of Se powder and Mn2(CO)10 in concentrated KOH/MeOH/MeCN solutions at 90 °C. Dianion 1 and its dimeric cluster, [(μ4-Se2){(μ3-Se2)2Mn3(CO)9}2]4- [(1)2], could undergo the reversible Se-Se bond breakage or reformation by the thermal cracking of (1)2 or self-dimerization of 1, showing the μ-Se•- radical character of 1. Complex 1 could react with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) to form the Se radical-captured complex [(μ-Se(TEMPO)) (μ3-Se2)2Mn3(CO)9]2- (1-TEMPO) or could react with alkylene bromides (CH2)nBr2 (n = 1, 2) to give the Mn4-based oxidative coupling products, [(μ4-Se2)(μ-Se2LSe)2Mn4(CO)12]2- (L = CH2, 2-CH2; Se, 2-Se). In addition, dianion 1 and its aggregated derivatives (1)2, 1-TEMPO, 2-CH2, and 2-Se exhibited unusual paramagnetic properties with the spin-state switching from S = 1 (Mn) + 1/2 (Se) to S = 1 (Mn), in which their magnetic centers were proved to be mixed-valent Mn atoms and the μ-Se•- radical, as evidenced by Evans method, superconducting quantum interference device, X-ray photoelectron spectra, electron paramagnetic resonance, and density functional theory calculations. Importantly, these clusters showed semiconducting behaviors with low and tunable energy gaps (1.50-2.01 eV) and varied electrical conductivities (2.52 × 10-8-4.58 × 10-9 S/cm), where efficient electron transports mainly arose from C-H(phenyl)···O(carbonyl) interactions within the solid-state frameworks.

Association of blood manganese, selenium with steatosis, fibrosis in the National Health and Nutrition Examination Survey, 2017-18

Background & aimsChronic liver disease is a growing health burden worldwide. Chronic metal exposures may be associated with non-alcoholic fatty liver disease (NAFLD). We aimed to evaluate the association of blood cadmium (Cd), mercury (Hg), lead (Pb), manganese (Mn), and selenium (Se) with two hallmark features of NAFLD: liver steatosis and fibrosis in the general U.S. population. MethodsWe analyzed transient liver elastography data from participants of the National Health and Nutrition Examination Survey (NHANES) 2017–18, using ordinal logistic regression analyses to evaluate the cross-sectional association between blood metal concentrations and clinical stages of steatosis and fibrosis. We applied survey weights, strata, and primary sampling units and analyses were conducted using the R survey package. Results4,154 participants were included. Median (IQR) for blood Mn and blood Se were 9.28 (7.48–11.39) and 191.08 (176.55–207.16) μg/L, respectively. Per interquartile range increase of natural log transformed blood Mn, the adjusted odds ratio (OR) (95% CI) was 1.59 (1.13–2.23) for a higher grade of steatosis and 1.16 (0.67–2.00) for liver fibrosis. The corresponding OR for steatosis was 2.00 (1.24–3.24) and 2.14 (1.04–4.42) in Black and Mexican American participants, respectively. The corresponding OR for liver fibrosis was 2.96 (1.42–6.17) for females. Per interquartile range increase of natural log transformed blood Se, the adjusted OR was 2.25 (1.30–3.89) for steatosis but 0.31 (0.13–0.72) for liver fibrosis. The inverse association of blood Se with liver fibrosis was also observed in males and White participants. Blood Cd, Hg, and Pb were not associated with liver steatosis and fibrosis in fully-adjusted models overall. ConclusionsIn NHANES 2017–18, higher blood Mn was positively associated with liver steatosis, and higher Se was positively associated with liver steatosis but negatively associated with liver fibrosis. Longitudinal studies are needed to examine the association of Mn and Se with fibrosis progression.

Long-term feeding of Atlantic salmon with varying levels of dietary EPA + DHA alters the mineral status but does not affect the stress responses after mechanical delousing stress.

Atlantic salmon were fed diets containing graded levels of EPA + DHA (1·0, 1·3, 1·6 and 3·5 % in the diet) and one diet with 1·3 % of EPA + DHA with reduced total fat content. Fish were reared in sea cages from about 275 g until harvest size (about 5 kg) and were subjected to delousing procedure (about 2·5 kg), with sampling pre-, 1 h and 24 h post-stress. Delousing stress affected plasma cortisol and hepatic mRNA expression of genes involved in oxidative stress and immune response, but with no dietary effects. Increasing EPA + DHA levels in the diet increased the trace mineral levels in plasma and liver during mechanical delousing stress period and whole body at harvest size. The liver Se, Zn, Fe, Cu, and Mn and plasma Se levels were increased in fish fed a diet high in EPA + DHA (3·5 %) upon delousing stress. Furthermore, increased dietary EPA + DHA caused a significant increase in mRNA expression of hepcidin antimicrobial peptide (HAMP), which is concurrent with downregulated transferrin receptor (TFR) expression levels. High dietary EPA + DHA also significantly increased the whole-body Zn, Se, and Mn levels at harvest size fish. Additionally, the plasma and whole-body Zn status increased, respectively, during stress and at harvest size in fish fed reduced-fat diet with less EPA + DHA. As the dietary upper limits of Zn and Se are legally added to the feeds and play important roles in maintaining fish health, knowledge on how the dietary fatty acid composition and lipid level affect body stores of these minerals is crucial for the aquaculture industry.

Growth surveillance indices and Kashin-Beck Disease in children.

Selenium, manganese, and calcium are necessary elements for maintaining normal growth and skeleton formation. Kashin-Beck disease mostly occurs in children, resulting in deformities, dwarfism, and disabilities. Selenium deficiency was considered a risk factor in China, while manganese was reportedly involved in it in Russia. Single-element regulation cannot be used in diagnosis because of unclear boundaries in patients compared to healthy individuals. In this study, new indices of elements were designed to predict the status of disease. MS (Mn/Se), CS (Ca’/Se), and MC (Mn/Ca’) values were designed, and prediction formulas were generated by comparing healthy children with those with Kashin-Beck disease via multiple linear regression analysis and discriminant analysis. In the disease group, 42.86% of patients had positive MS, CS, and MC values, and 57.14% of patients had positive MS and CS values. In the treatment group, the patients presented improved indices. In the prediction group, subjects with negative clinical criteria features were predicted by new indices, and 26.67% of them presented with positive MS, CS, and MC values, whereas 40.00% had positive MS and CS values. The 3D model of MS, CS, and MC refers to the setup of elements. The MS, CS, and MC indices are helpful in disease prediction, diagnosis, prognosis, and surveillance. The distribution model of the indices could serve in the growth surveillance of children.

Mn-incorporated nickel selenide: an ultra-active bifunctional electrocatalyst for hydrogen evolution and urea oxidation reactions.

We report Ni-Mn-Se supported on Ni foam as a highly active and stable bifunctional electrocatalyst that exhibits overpotentials of 28 and 122 mV to reach a current density of 10 mA cm-2 for the hydrogen evolution reaction (HER) and urea oxidation reaction (UOR), respectively, and maintains its stability for over 50 h in both reactions. In addition, an overall urea splitting cell voltage of 1.352 V is needed at the current density of 10 mA cm-2 for the optimized electrode.

Drought effects on the mineral composition of the leaves of Actinidia species

Against the background of global climate change, drought stress has become one of the environmental limiting factors that can significantly influence the growth and development of crop plants. Drought stress conditions also cause changes in plant physiological and metabolic processes. The influence of soil drought on the mineral composition of the leaves of two Actinidia species with С3-type photosynthesis, namely, Actinidia argutа (Siebold & Zucc.) Planch. ex Miq. cultivar ‘Taezhny Dar’ and Actinidia kolomikta (Maxim. & Rupr.) Maxim. cultivar ‘Narodnaya’, was studied through energy dispersive spectrometry. The investigations were carried out during 2020 to 2021 at the Department of Genofonde and Bioresources of Plants, Federal Scientific Center for Horticulture, Moscow. The present research revealed that actinidia leaves contained the following major elements: K (11.19 mass% to 13.84 mass%), Ca (7.83% to 12.08 mass%), Cl (6.20 mass% to 7.33 mass%), and Mg (2.98 mass% to 3.44 mass%). Low values were recorded for Mo (1.19 mass% to 4.49 mass%) and P (0.83 mass% to 1.25 mass%). In both species, the mineral elements K and Ca were present at high levels. A positive correlation was observed between Mg–P, K–Mn, Mn–Se, Cu-Se, P–Si, Na–Mo, and Si–Mn in the leaves of A. argutа and between Cl–Ca, Mo; P–Si, Mo; and K–Ca in the leaves of A. kolomikta. Under stress conditions, the ratios of K/Ca and K/P declined to 0.9 and 6.3, respectively, whereas those of K/Cl, K/Mg, and K/Mo increased to 3.8, 4.4, and 2.7, respectively. The present studies confirmed that actinidia leaves contained high concentrations of minerals, especially K, Ca, P, and Mg, and that the accumulation of mineral elements in actinidia plant leaves under drought conditions varied depending on the species.

Biochemical and cytological features of onion bulbs and leaves collected from various ecogeographical origins

Against the background of global climate change, drought stress has become one of the environmental limiting factors that can significantly influence the growth and development of crop plants. Drought stress conditions also cause changes in plant physiological and metabolic processes. The influence of soil drought on the mineral composition of the leaves of two Actinidia species with С3-type photosynthesis, namely, Actinidia argutа (Siebold & Zucc.) Planch. ex Miq. cultivar ‘Taezhny Dar’ and Actinidia kolomikta (Maxim. & Rupr.) Maxim. cultivar ‘Narodnaya’, was studied through energy dispersive spectrometry. The investigations were carried out during 2020 to 2021 at the Department of Genofonde and Bioresources of Plants, Federal Scientific Center for Horticulture, Moscow. The present research revealed that actinidia leaves contained the following major elements: K (11.19 mass% to 13.84 mass%), Ca (7.83% to 12.08 mass%), Cl (6.20 mass% to 7.33 mass%), and Mg (2.98 mass% to 3.44 mass%). Low values were recorded for Mo (1.19 mass% to 4.49 mass%) and P (0.83 mass% to 1.25 mass%). In both species, the mineral elements K and Ca were present at high levels. A positive correlation was observed between Mg–P, K–Mn, Mn–Se, Cu-Se, P–Si, Na–Mo, and Si–Mn in the leaves of A. argutа and between Cl–Ca, Mo; P–Si, Mo; and K–Ca in the leaves of A. kolomikta. Under stress conditions, the ratios of K/Ca and K/P declined to 0.9 and 6.3, respectively, whereas those of K/Cl, K/Mg, and K/Mo increased to 3.8, 4.4, and 2.7, respectively. The present studies confirmed that actinidia leaves contained high concentrations of minerals, especially K, Ca, P, and Mg, and that the accumulation of mineral elements in actinidia plant leaves under drought conditions varied depending on the species.

Determination of arsenic, cadmium, selenium, zinc and other trace elements in Bangladeshi fish and arsenic speciation study of Hilsa fish flesh and eggs: Implications for dietary intake

Exposure to As from drinking water and its impact on the health of the Bangladeshi population has received much attention. However, very little information is available regarding As exposure through consumption of fish, which is the main source of animal protein for the majority of Bangladeshis. In this study, concentrations of As, Cd, Pb, Mn Se and Zn in different types of fish, consumed by Bangladeshis, were determined using Inductively Coupled Plasma Mass Spectrometry. Daily intakes of the toxic elements As, Cd and Pb through fish consumption were estimated to be 31.8, 0.4 and 4.8 μg/day, respectively. Hilsa (Tenualosa ilisha) contained the highest concentrations of total As (mean ± SD was 2.55 ± 1.3 mg/kg; n = 15) among the fish analysed. However, toxic inorganic As species were not detected. The dominant As species in Hilsa fish were: dimethylarsenic acid, arsenobetaine and arsenosugars, at 69, 11 and 20% of total As, respectively. The high concentration of Cd detected in Hilsa eggs (average 278 ± 518 μg/kg; range 7.4–1725 μg/kg; n = 10) is of concern since this may have harmful effects on the development of embryos and lead to a decline in the Hilsa population or the quality of the fish. It can also be harmful to those who consume Hilsa eggs on a regular basis. Selenium was found to be highest in Shoal (Micropterus cataractae) fish and a type of small fish, and lowest in Mrigal (Cirrhinus cirrhosis). Small fish species contained Mn and Zn at 7.1- and 4.3-fold higher concentrations, respectively, compared to big fish species. Keski (Corica soborna), a small fish species, contained by far the highest concentrations of Mn (52 mg/kg) and Zn (140 mg/kg), although the concentration of As (1.4 mg/kg) in this fish was lower than that of several other fish species. Small fish species are often consumed whole, including the bones, and therefore the essential trace elements present are potentially bioavailable for cellular metabolism. Our study shows that the Bangladeshi population can easily meet their daily requirement of Se and Zn from consumption of fish such as Shoal fish (Se and Zn), Hilsa fish (Se and Zn) and Keski fish (Se and Zn). Consumption of small fish (such as Keski) and big fish (such as Hilsa) from Bangladesh can provide valuable sources of essential trace elements as part of a balanced diet and thus negate the need for supplements and biofortification of certain foods. Ours is a small study and a detailed total dietary intake and human biomonitoring studies, that includes coverage of different socio-economic groups, are needed in Bangladesh before giving people supplements or biofortified foods.

Concentration of essential chemical elements in whole blood and in paranasal sinuses mucosa is related to chronic rhinosinusitis severity in children

Objectives to evaluate the association between essential chemical element levels in whole blood and in pathologic mucosa and chronic rhinosinusitis severity in children.
 Material and methods. A total of 154 children aged from 6 to 17 years were examined. Among them, 88 children had chronic rhinosinusitis (CRS) and underwent functional endoscopic sinus surgery (FESS). The 66 healthy children were included in the control group. Life quality was assessed using SNOT-20 (Sino-Nasal Outcome Test-20). Endoscopic and computer tomography findings were evaluated using Lund Kennedy and Lund Mackay scales, respectively. The assessment of essential element levels in whole blood samples was performed using inductively-coupled plasma mass-spectrometry.
 Results. The obtained data demonstrate that total SNOT-20 scores in CRS patients were 68% higher than in controls. At the same time, whole blood calcium, selenium, zinc, and magnesium levels were 6%, 28%, 20%, and 3% lower than the respective control values. The analysis of pathologic mucosa demonstrated that the chemical element contents were reducing in the following order: Ca Mg = Fe Zn Cu Mn Se. However, only whole blood selenium level correlated significantly with its tissue level. In multiple regression models, the whole blood Se level was inversely associated with SNOT-20 and Lund Mackay total scores.
 Conclusion. Therefore, the obtained data allow to propose the potential role of altered calcium, magnesium, zinc and selenium metabolism in CRS progression.

Engineering (Ni, Co, Mn) Se nanoarrays with 3D-Printed wave-structure carbon-rich lattice towards ultrahigh-capacity, complex-stress and all-climate energy storage

Energy storage capacity and environmental adaptability as the two important elements of energy storage devices towards an intelligent Internet of things era, the two often do not co-existence. The continuous exploration of advanced multifunctional electrodes is of great significance to achieve balance between superior capacity and complex service environment adaptability. Notably, it still remains a great challenge to realize high capacity under extreme complex stress and climate environments. Herein, coralline-like (Ni, Co, Mn) Se nanoarrays were synthesized on highly-conductive 3D-printed wave-structure carbon-rich periodic lattices as multitasking free-standing, binder and current collector-free electrodes towards editable ultrahigh-capacity, complex-stress and all-climate energy storage. As expected, the as-prepared wave-structure electrodes exhibit a combination of editable ultrahigh capacitive performance (5.6–7.8 F cm−2 at 1 mA cm−2), superb mechanical resistance (up to 260 MPa) and wide climate compliance (temperature: from −20 to 85 °C; humidity: from 20 to 85% RH). More impressively, such a multipurpose device also demonstrates a record-high areal energy density of 260 μWh cm−2, and an ultralong lifespan even under extreme conditions of 85 °C & 85% RH & 3 MPa. This strategy opens up novel avenues to explore various bespoke multifunctional integrated devices and multiscale structural materials for future smart life.

Enhanced exciton binding energy, Zeeman splitting and spin polarization in hybrid layered nanosheets comprised of (Cd, Mn)Se and nitrogen-doped graphene oxide: implication for semiconductor devices

The exciton properties of (Cd,Mn)Se-NrGO (nitrogen doped reduced graphene oxide) hybrid layered nanosheets have been studied in a magnetic field up to 10 T and compared to those of (Cd,Mn)Se nanosheets. The temperature dependent photoluminescence reveals the hybridization of inter-band exciton and intra-center Mn transition with enhancement of the binding energy of exciton-Mn hybridized state (80 meV with respect to 60 meV in (Cd,Mn)Se nanosheets) and increase of exciton—phonon coupling strength to 90 meV (with respect to 55 meV in (Cd,Mn)Se nanosheets). The circularly polarized magneto—photoluminescence at 2 K provides evidence for magnetic field induced exciton spin polarization and the realization of excitonic giant Zeeman splitting with g eff as high as 165.4 ± 10.3, much larger than in the case of (Cd,Mn)Se nanosheets (63.9 ± 6.6), promising for implementation in spin active semiconductor devices.

58 The Effect of Altering Dietary Manganese and Selenium Levels on the Growth Performance and Blood Manganese-superoxide Dismutase Activity in Nursery Pigs

Abstract The objective of this study was to determine the effect of altering dietary levels of manganese and selenium on growth performance and MnSOD specific activity. Weaned piglets were blocked by weight (n = 216; 5.21 ± 1.17 kg; 21 ± 3 d) and sex (2 barrows and 2 gilts/pen). Pens within a block were randomly assigned to dietary treatments in a factorial design with main effects of Se (0.1 and 0.3 ppm) and Mn (0, 12, and 24 ppm). Diets (n = 9 pens/treatment) were fed in three phases (P1 = d 1–7, P2 = d 7–21, P3 = d 21–35). Pigs and orts were weighed weekly and pigs were bled on d 0, 7, 21, and 35 for analysis of specific activity of red blood cell MnSOD. Data were analyzed as 2x3 factorial design via SAS PROC GLM. There were no Se effects or Mn x Se interactions observed. There was a linear increase (P < 0.05) in overall ADG (397, 424, and 438 g day-1pig-1 for 0, 12, 24 ppm Mn, respectively). There was a linear trend (P < 0.1) in overall ADFI (557, 560, 592 g day-1pig-1 for 0, 12, 24 ppm Mn, respectively). Feed efficiency (d 0–35) across increasing Mn levels were 0.71, 0.76, 0.74 (P > 0.1). MnSOD activity in RBC increased from d 0–7, peaked on d 7 and decreased to d 35. On d 7, diets with 12 and 0 ppm Mn had significantly increased (P < 0.05) MnSOD activity (0.91 and 0.87 IU mg-1 protein, respectively) compared to diets with 24 ppm Mn (0.67 IU mg-1 protein). The dietary treatment that best maintained MnSOD activity was 0.3 ppm Se and 12 ppm Mn supplemented, while ADG was maximized in the diet with 0.3 ppm Se and 24 ppm Mn supplementation.

Nutritional Intervention Strategies Using Dietary Antioxidants and Organic Trace Minerals to Reduce the Incidence of Wooden Breast and Other Carcass Quality Defects in Broiler Birds.

Wooden breast (WB) is a degenerative myopathy seen in modern broiler birds resulting in quality downgrade of breast fillets. Affected filets show increased toughness both before as well as after cooking and have decreased water holding capacity and marinade pick up compared to normal fillets. Although the exact etiology is unknown, the circulatory insufficiency and increased oxidative stress in the breast muscles of modern broiler birds could be resulting in damage and degeneration of muscle fibers leading to myopathies. Three independent experiments were conducted to evaluate the effect of various dietary interventions on the incidence of WB when birds are exposed to oxidative stress associated with feeding oxidized fat and mild heat stress. Feed additives such as dietary antioxidant [Ethoxyquin (ETX)], mineral methionine hydroxy analog chelate (MMHAC) of Zn, Cu, and Mn, and organic selenium (Org Se) were tested at recommended levels. In experiment 1, ETX reduced (P < 0.05) the incidence of severe WB induced by oxidized fat diet. The magnitude of improvement in percentage of normal (no WB) filets and reduction in muscle lipid peroxidation was greater (P < 0.05) when ETX and MMHAC were fed together as shown by experiment 2. In birds exposed to mild heat stress (Experiment 3), feeding MMHAC by itself reduced (P < 0.05) tissue damage by reducing incidence of tibial head lesions, skin scratches, breast blisters, in addition to increasing the incidence of normal (no WB) fillets. When MMHAC was combined with ETX and Org Se, further improvement (P < 0.05) in normal (no WB) filets was observed. In summary, under different oxidative stress conditions, dietary intervention programs that contain ETX, MMHA-Zn, -Cu, and -Mn and Org Se can improve performance and increase carcass integrity, reducing problems, such as WB, either independently or with additive effect. This effect is most likely attained by simultaneously improving the exogenous and endogenous antioxidant status, reducing oxidative stress, and improving tissue healing process of the bird.

Heavy Metals Content in Kaolin Mined Soil and Water Body at Ohiya, Umuahia South, Abia State, Nigeria

Heavy metals (HM) have been a global concern for its toxic and detrimental effect on the environment especially when it exceeds the permissible limit through anthropogenic activities like kaolin mining. Kaolin mining has improved the economic wellbeing of the local people through employment and otherwise; and at the same time attached with environmental consequences that threatens the livelihood of the community members. This study was carried out to ascertain the concentrations of selected heavy metals in kaolin mined soils and water body and its pollution density using single pollution indices such as contamination factor (CF), geo-accumulation (Igeo) and ecological risk factor (Er ). Soil sample were collected from three different kaolin mined sites labelled (A,B and C) also surface water samples were collected from upper and down streams of Iyi-ugbohoroAmaudara, both samples were digested and elemental analysis was carried out using Atomic Absorption Spectrophotometer (AAS UNICAM 919 model). The concentration of the metals in three different kaolin mined soil samples ranges from Pb(40.00, 52.00 and 55.09 mg/kg) Cr(45.01, 70.00 and 71.00 mg/kg) Ni( 32.10, 50.50 and 51.00 mg/kg) Cd( 2.16, 6.25 and 6.15 mg/kg) Co( 19.68, 57.06 and 56.00 mg/kg) Se(1.06, 0.50, and 1.00 mg/kg) Mn(0.001, 0.01 and 0.01 mg/kg) Hg( 2.01, 2.00 and 2.50 mg/kg) As( 1.07, 1.10 and 1.05 mg/kg) and Cu(33.01, 60.00 and 57.5 mg/kg). Results from single pollution indices used for the selected heavy metals from kaolin mined soil, samples (A,B and C) showed that Mn, As, Cr, Ni and Cu indicated low to moderate contamination factor while Cd, Se, Co and Hg indicated high to very high contamination factor in all the samples. The distribution trend of heavy metals concentrations in the upper and down streams of the river body during wet season, showed that there were significant difference between upper and down streams while dry season showed variations in significant differences between the upper and down streams of some of the heavy metals. The study therefore concludes that kaolin soils are contaminated with heavy metals as a result of kaolin deposit and its mining activities. The single pollution indices used for the study pointed out that Cd, Se, Co and Hg are very high in the kaolin soils. The surface waters of Iyi-ugbohoroAmaudara River at the study area are polluted with heavy metals as a result of kaolin mining activities in the area; more especially during wet season of the study. Consequently, these outcomes would pose a toxic effect to both fauna and flora and possibly threatens the aquatic lives and the local populace.

Distribution Characteristics of Selenium in a Soil-Crop System and the Threshold of Selenium-Rich Soils

In order to determine the distribution characteristics of Se in soil-crop systems, we carried out a study on the Se-rich soil threshold by collecting 8789 surface soils and 155 deep soils in the Qianjiang District of Chongqing City, China, and 141 corn seeds and 159 rice seeds (simultaneously collecting 141 and 159 corresponding root soil samples, respectively). We then analyzed the Se content, organic matter, S, Mn, TFe2O3, Al2O3, and K2O in soils and crops, and soil pH. We also analyzed the surface layer using geostatistical methods and the distribution characteristics of Se in deep soils using multiple regression analysis to study the factors influencing the bioavailability of Se. Based on the contents of each component of root soil and the Se contents of crops, the Se rich threshold was examined. The results showed that the high-Se soils in the study area account for 32.72% of the total area; the distribution of Se contents in the surface and deep soils is mainly controlled by the parent material, the source of soil Se is stable, and the surface enrichment is obvious. The Se-rich rates of corn and rice were 75.35% and 46.81%, respectively, and soil organic matter and S content will limit the bioavailability of Se. If the planted crop is corn, it is recommended to use 0.3 mg·kg-1 as the Se-rich soil threshold; if the planted crop is rice, when the soil pH is ≤ 7.5, it is recommended to use 0.3 mg·kg-1 as the Se-rich soil threshold, while at a soil pH>7.5, it is recommended to use 0.4 mg·kg-1 as the threshold. Similarly, if other large crops are planted in the study area, this method can also be used to carry out a study on the proposed Se-rich soil threshold.

The magnetic, optical and electronic properties of Mn–X(X = O, Se, Te, Po) co-doped MoS2 monolayers via first principle calculation

The magnetic and optical properties studies in monolayer transition-metal dichalcogenides have attracted attention because of the manufacture spintronic, electronic and photonic devices. This paper reported the magnetism and optical properties of Mn–O, Mn–Se, Mn–Te, Mn–Po co-doped MoS2 monolayer systems via first principle calculation, results show Mn-X(X = O, Se, Te and Po) co-doped MoS2 monolayer systems appear half-metal (HM) ferromagnet, their corresponding magnetic moments are 1.06 μ B, 1.04 μ B, 1.04 μ B, 1.03 μ B, respectively. Co-doped systems have smaller band gaps due to effective charge compensation among Mn–O, Mn–Se, Mn–Te and Mn–Po atoms. According to calculation, we find Mn–O co-doped MoS2 monolayer has the lowest formation energy in four co-doping systems. Thus the Mn–O co-doped MoS2 monolayer has the best stability. The Mn–Se co-doped MoS2 monolayer has the highest static dielectric constants and refractive index and In energy range of 0 to 1.5 eV, the transmittance of intrinsic MoS2 system is higher than that of all co-doped MoS2 systems obtained by absorption coefficient

Design and Characterization of a Sharp GaAs/Zn(Mn)Se Heterovalent Interface: A Sub-Nanometer Scale View.

The distribution of magnetic impurities (Mn) across a GaAs/Zn(Mn)Se heterovalent interface is investigated combining three experimental techniques: Cross-Section Scanning Tunnel Microscopy (X-STM), Atom Probe Tomography (APT), and Secondary Ions Mass Spectroscopy (SIMS). This unique combination allowed us to probe the Mn distribution with excellent sensitivity and sub-nanometer resolution. Our results show that the diffusion of Mn impurities in GaAs is strongly suppressed; conversely, Mn atoms are subject to a substantial redistribution in the ZnSe layer, which is affected by the growth conditions and the presence of an annealing step. These results show that it is possible to fabricate a sharp interface between a magnetic semiconductor (Zn(Mn)Se) and high quality GaAs, with low dopant concentration and good optical properties.