Cation Iron Research Articles

Comparative evaluation of growth performance and soil quality of two age sequences of <i>Gmelina arborea</i> plantation in University of Port Harcourt, Nigeria

This study was conducted in 2019 to compare the growth performance and soil quality of two agesequences of Gmelina arborea plantation within the premises of the University of Port Harcourt, Nigeria. Data were collected from two stands of G. arborea established in 2011 and 2015. Growth performance was evaluated based on tree growth variables and above-ground carbon stored. Tree growth variables estimated were total height (TH), diameter at breast height (DBH), crown height (CH), crown diameter (CD) and merchantable height (MH). Topsoil (0 – 30 cm) samples collected from the two sites were analyzed for particle size distribution, organic carbon (OC), total nitrogen (TN), available phosphorus (Av.P), exchangeable bases (Mg, Ca, K and Na), exchangeable acidity (Al+ H+), effective cation exchange capacity (ECEC), base saturation (BS), pH, Manganese (Mn), Iron (Fe), Copper (Cu) and Zinc (Zn). The above-ground biomass (AGB) and carbon stock (CS) were also determined. T-test was used to test for significant difference in the measured parameters between the two age-sequences of G. arborea. Higher values for TH, DBH, CS and MH were recorded for the older stand although the differences between the two age-sequences were not significantly different (p ≥ 0.05). The AGB and CS per hectare were higher for the older than the younger G. arborea stand (302.27 m3 ha-1 and 151.52 m3 ha-1, respectively). Higher values for silt, clay, Ca, Mg, Al+ H+, ECEC, BS, Mn, Fe and Zn were also recorded for the older stand. However, the observed differences were only significant (p < 0.05) for clay, pH, Av.P, Mn and Fe. The study revealed that although soil properties, tree growth as well as carbon sequestration capacity of G. arborea stand improved/increased with age, the differences were mainly not statistically significant (p ≥ 0.05) between the two (eight and four years) age-sequences.
 Keywords: Gmelina arborea, age sequence, soil quality, carbon sequestration

Excess sulfur and Fe elements drive changes in soil and vegetation at abandoned coal gangues, Guizhou China

Coal gangue piles accumulate outside mines and can persist for years, negatively impacting the regional environment. To determine the main cause of soil pollution at coal gangues, several coal gangues in Guizhou Province, China that had undergone natural recovery via native plants for 8 years were investigated in summer 2019. Three plots (2 m × 2 m) from the coal gangue area were selected for the treatment (GP). Control plots that were 100 m away from GP were also investigated in contrast (CK-near). In addition, plots from forest, farmland and lake land that were far from GP and largely undisturbed were also investigated as more extreme contrasts (CK-far). A series of soil indicators that can be affected by coal-gangue, such as heavy metals (Mn, Cr, Cd, Ni, Zn, Cu, Pb), As, pH, cation exchange capacity (CEC), sulfur (S) and iron (Fe), were tested for in the plots. Plant species, coverage and height were also analyzed to uncover biodiversity and dominant species information. The results suggested that coal gangue significantly influences soil S, pH and plant species after 8 years of natural recovery. The CK-far plots contained relatively low soil sulfur content, normal pH (close to 7) and abundant plant biodiversity. Generally, pH related positively with both the Patrick (R = 0.79, n = 22, p < 0.001) and Shannon indices (R = 0.67, n = 22, p < 0.001); the soil S related negatively with both the Patrick (R = 0.85, n = 22, p < 0.001) and Shannon indices (R = − 0.79, n = 22, p < 0.001). S content was highest (S = 1.0%) in GP plots, was lower in CK-near plots (S = 0.3%) and was the lowest of all in the plots distant from the coal mine (S = 0.1%, CK-far). S content was negatively correlated with pH. Soil pH decreased significantly, from 7.0 in CK-far, to 5.9 in CK-near, to 4.2 in GP. Soil Fe was 3.4 times higher in GP and CK-near than in CK-far. The excess sulfur and Fe elements and the acidified soil drove changes in soil and vegetation in the coal gangue areas. After 8 years of natural recovery, only a few plants, like Miscanthus floridulus, were able to live near the coal gangue in the area where the soil was still acidic and high in S and Fe.

Initial Fe3O4(100) Formation on Fe(100)

The initial oxidation of Fe(100) at 400 °C has been studied by X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and low-energy electron diffraction, in combination with density functional theory calculations. The first observed well-ordered surface oxide is formed at a coverage of ∼3 oxygen atoms per unreconstructed surface Fe(100) atom. STM shows that this surface oxide is terminated by straight atomic rows exhibiting a p(2 × 1) periodicity. However, already for oxide films with a coverage of ∼4 oxygen atoms (corresponding to one Fe3O4 unit cell thickness), wiggly atomic rows appear similar to the c(2 × 2) reconstructed Fe3O4(100)-surface with the Fe3O4 unit vectors rotated 45° to Fe(100). The wiggly rows are a consequence of subsurface cation iron vacancies, which previously have been observed for bulk surfaces. The formation of subsurface vacancies is supported by the XPS O 1s signature, which is modeled by considering the core-level shifts for all oxygen atoms in the film. Throughout the oxidation series, the microscopy results reveal a layer-by-layer (Frank–van der Merwe) growth.

English

The research was conducted in tomato-growing lands of Lâpseki, Ezine, Bayramic and Central districts of Canakkale province, Turkey. The aim of the study is to check the suitability of the field for tomato farming and to produce a solution if there is a problem. Disturbed soil samples were taken from 114 points with certain coordinates, at a depth of 0 to 30 cm, and analyses were performed. In the soil samples, texture, soil reaction (pH; 1:2.5), calcium carbonate (CaCO3%), phosphorus (P; kg.ha-1), cation exchange capacity (CEC; meq.100 g-1), iron (Fe; ppm), manganese (Mn; ppm), zinc (Zn; ppm), copper (Cu; ppm) and clay (%) analyses were conducted, and characteristic maps of the region were prepared according to the results of the analyses. Based on these results, the present condition and suitability of the soils were evaluated, and simple statistics along with correlations of the analyzed parameters were examined. For the problems of the area, in low pH areas, it was deemed necessary to apply calcium carbonate (CaCO3) or calcium hydroxide [Ca(OH)2] together with physiological alkaline fertilizers. As per the high pH areas, it was necessary to apply elemental sulfur together with physiological acid fertilizers. It was also concluded that Zn application was necessary for the 43.85% of the area with Zn deficiency. Key words: Efficiency level, nutritional status, plant nutrition, tomato.

Ethnopharmacological plants used to treat hepatitis and their anti-oxidant activity of district of Bobo-Dioulasso (Burkina Faso)

Background: Plants are frequently used by traditional healer for the care of the hepatic pathologies.Objective: This study is part of the valorization of the hepatoprotective potential of some plants used in traditional medicine for the care of hepatitis in the Hauts-Bassins region of Burkina Faso.Materials and methods: A survey realized in this region allowed retaining 5 species, after the classification according to the frequency of quotation and the bibliographic review, among the 44 species recorded: Anogeissus leiocarpus (DC.) Guill. &amp; Perr (Combretaceae), Balanites aegyptiaca Delie. (Balanitaceae), Cassia alata L. (Ceasalpiniaceae), Opilia celtidifolia (Guill. &amp; Perr.) Endl. (Opiliaceae) and Ziziphus mauritiana L. (Rhamnaceae). The content in phenolic compounds of the aqueous extracts of these plants was determined. Their antioxidant activity was evaluated by two methods: discoloration of radical cation ABTS and iron reduction (FRAP).Results: Anogeissus leiocarpus and Ziziphu smauritiana gave the strongest antioxidant activities and high phenolic compounds (total phenolics, total flavonoids, total tannins and flavonols). The antioxidant activity (FRAP, ABTS) was associated with the total phenolic content of the extracts expressed in tannic acid equivalent per 100 grams of dry matter with R2 of 0.8148 and 0.7966.Conclusion: The antioxidant activity and the content phenolic compounds observed during this study with Anogeissus leiocarpus and Ziziphus mauritiana indicates that these two plants have a high hépato protective potential which can justify their use by the Traditional healer in the care of hepatitis.

Electroactive polymers made by loading redox ions inside crosslinked polymeric hydrogels. Effects of hydrophobic interactions and solvent dynamics

Electroactive polymers are made by loading redox complexes inside different polymeric crosslinked hydrogels. A redox cation (tris(phenanthroline)iron(II) (TPFeII) is sorbed in anionic, neutral and cationic hydrogels while redox anions (ferricyanide) is taken up inside an anionic hydrogel. Moreover, a redox anion (nitrite) and a cation (TPFeII) are simultaneously absorbed in an anionic hydrogel. Homopolymeric hydrogels of 2-acrylamidopropanesulfonic acid (PAMPS), acrylic acid (PAA) or (3-acrylamidopropyl)trimethylammonium chloride) (PAPMTAC), crosslinked with bisacrylamide, are synthesized by radical polymerization. The same method is used to produce a 1:1 copolymeric hydrogel of acrylic acid and 2-acrylamidopropanesulfonic acid (PAA-co-AMPS). The physicochemical properties of the hydrogels are evaluated by measuring the swelling kinetics, in the same conditions of the electrochemical measurements. The cyclic voltammetric response of all electroactive polymers show quasireversible electron transfer (Eqrev mechanism) while the hydrogel loaded with TPFeII and nitrite show a catalyzed oxidation (EqrevC mechanism). The electrochemical parameters (diffusion coefficient and charge transfer constant) of TPFeII loaded inside PAMPS, PAA and PAA-co-AMPS are measured using chronoamperometry and digital simulation of the cyclic voltammetry. The Stokes-Einstein equation is used to calculate the effective viscosity of the hydrogel matrixes using the diffusion coefficients of a redox complex (TPFeII) determined inside the hydrogels and the same parameters determined in aqueous solution. The calculated viscosity correlates, with a negative slope, with the swelling rate constant of the hydrogel matrix. The heterogeneous charge transfer of the redox complex inside ionomers (PAMPS and PAA-co-PAMPS) is nearly as fast as in solution, while the charge transfer inside the neutral PAA is ca. 100 times smaller. The measured charge transfer constants correlate with the calculated viscosity, revealing the effect of solvent dynamics on the charge transfer, according to Marcus theory for strongly adiabatic electron transfer. In that way, it is shown that the electrochemical measurements are able to monitor the local solvation properties of the hydrogel matrix. These results suggest novel ways to produce electroactive polymers by loading redox active substances inside hydrogels, even when the hydrogel matrix is neutral or bear the same charge than the redox probe. The redox complexes are present as dilute solutions and the hydrogel dimensions fulfill the semi-infinite diffusion boundary conditions. Therefore, the data analysis can be performed using the theoretical framework for electrochemical measurements in liquid solvents.

Synthesis, Structure, and Magnetic Characterization of a Series of Iron(II) Coordination Frameworks with 2, 6‐Bis(1, 2,4‐triazole‐4‐yl)pyridine

AbstractBased on the bis‐triazole ligand 2, 6‐bis(1, 2,4‐triazole‐4‐yl)pyridine (L), the triazole‐iron(II) complexes [Fe(L)2(dca)2(H2O)2]·2H2O (1) (Nadca = sodium dicyanamide), {[Fe(μ2‐L)2(H2O)2]Cl2}n (2), and {[Fe(μ2‐L)2(H2O)2](ClO4)2·L·H2O}n (3) were isolated by solvent diffusion methods. When iron(II) salts and Nadca were used, compound 1 was isolated, which contains mononuclear Fe(L)2(dca)2(H2O)2 units. When FeCl2 or FeClO4 were used, one‐dimensional (1D) cation iron(II) chains (2) and two‐dimensional (2D) cation iron(II) networks (3) were isolated indicating anion directing structural diversity. Moreover, variable‐temperature magnetic susceptibility data of 1–3 were recorded in the temperature range 2–300 K. The magnetic curve of complex 2 was fitted by using the classical spin Heisenberg chain model indicating anti‐ferromagnetic interactions (J = –5.31 cm–1). Obviously complexes 1–3 show no detectable thermal spin crossover behaviors, the lack of spin‐crossover behavior may be correlated with FeN4O2 coordination spheres in 1–3.

To construct the eukaryotic expression vector of NOR1 gene and analyzeits effect on the liver cancer cell

目的 NOR1基因真核表达载体pcDNA3.1(+)的构建并了解其对肝癌细胞系HepG2生长的影响.方法将NOR1cDNA亚克隆至pcDNA3.1(+)真核表达载体上,并把重组质粒pcDNA3.1(+)/NOR1经脂质体转染至HepG2细胞中,运用MTT法、台盼蓝排斥等试验、流式细胞仪等分析NOR1基因对肝癌细胞HepG2生物学活性的影响.结果成功构建了NOR1基因真核表达体pcDNA3.1(+)/NOR1,经pcDNA3.1(+)/NOR1转染后的HepG2细胞生长速度明显抑制(P<0.05),且细胞从G0/G1期进入S期明显延缓.结论重组质粒pcDNA3.1(+)/NOR1能在HepG2细胞内表达,且能影响HepG2细胞的生长。

The crystal structure analysis of iron nitroprusside, Fe[Fe(CN)5NO]�3H2O

The crystal structure of iron(II) pentacyanonitrosylferrate trihydrate has been determined from three dimensional, single-crystal X-ray diffraction data. Fe[Fe(CN)5NO]·3H2O crystallizes in the monoclinic space group P21/n with lattice constants,a=7.205(1),b=14.641(2),c=10.680(1) A,β=91.14(1)° andZ=4,Dm=1.89(1) g cm−3 andDx=1.92 g cm−3. Final full-matrix least-squares refinement of 1691 unique reflections yieldedR=0.024 andRw=0.028. Both iron atomic centers have distorted octahedral symmetries. The cation iron center is coordinated by five cyanide ligands and one water molecule, while the second iron center is coordinated by five cyanide ligands and one nitrosyl group. Cyanide bridging links the metal centers. Two uncoordinated water molecules, O(2) and O(3), are hydrogen bonded to the coordinated water molecule, O(1), and occupy channels in the crystal lattice. Important mean bond distances for iron nitroprusside are: Fe(cation)-N=2.159(17), Fe-C=1.936(4) and C=N=1.144(6) A. Other notable bond lengths include: Fe-O(1)=2.152(2), Fe-NO=1.669(2) and N≡O=1.131(3) A. The distances between the coordinated water molecule and two uncoordinated water molecules are 2.855(3) and 2.740(3) A.

Growth of mixed cation iron garnets in the ytterbium-gallium and yttrium-calcium silicate systems

Single crystals with the compositions (A) = Yb 3Fe 5 − xGa xO 12 with x varying from 0.5 to 4.0 and (B) = Y 2.9 − xBi 0.1Ca xFe 5 − x- Si xO 12 with x varying from 0.6 to 1.3 have been grown from flux. Crystals of compositions (A) are crystallized from a PbO/PbF 2 solvent, whereas crystals of compositions (B) are from a PbO/B 2O 3 solvent. The unit-cell dimensions, the ferrimagnetic Curie temperature and the segregation coefficients of Ga 3+ in (A) and Ca 2+ in (B) have been determined. The difference between the two fluxes is discussed.