Precipitation and Hydrolysis of Thorium in Aqueous Solution. IV. Studies of the Systems: Thorium Nitrate-Sodium Fumarate and Thorium Nitrate-Potassium Maleate

Precipitation of thorium from aqueous solutions of thorium nitrate and sodium fumarate and potassium maleate respectively has been investigated for a broad range of concentrations of preci~ pitation components and pH. From the results of chemical analyses and from the DT A and IR spectra the most probable formulas of the formed precipitates are: Th(H-fumarate)2 (0H)2 X 5 H 20 and [ g~ Thg~ (Mal Th g~ )4] X 6 H20. In the soluble mixed hydroxo maleato thorium complex, which is in equilibrium with thorium hydroxide, probably three hydroxide ions are bound to one thorium. It has been found that with fumarate ion thorium does not form a soluble complex

Precipitation and Hydrolysis of Thorium(IV) in Aqueous Solution. III. The Composition of the Precipitates in the System Thorium Nitrate - Potassium Phthalate

Precipitation from water solutions of thorium nitrate and potassium phthalate was investigated for a broad range of concentrations of both precipitation components. The influence of pH and of time on the formation of various precipitates was studied, the composition and characteristics of the precipitates being determined by chemical analysis, and IR and NMR spectra. The following precipitates were characterized: Th(OH).:1 without water of crystallization; Th (Phthalateh without water of crystallization; Thorium hydroxide-phthalate polymer with unknown formula. An empirical formula was derived, which shows the conditions for precipitation of thorium hydroxide in the presence of potassium phthalate. In the soluble mixed hydroxo-phthalato thorium complex, two OH- ions are bound per one thorium

Method for Studying Mixed Hydroxo Complexes within the pH Range where the Ligand is not Protonated

A general method is presented, which can be used for the determination of the composition (j, p) of soluble mononuclear mixed hydroxo complexes, [B(OH)iAP], formed in the presence of an excess of the ligand and within the pH range in which the ligand is not protonated. In order to find the value of j two titration curves are compared: (1) the curve obtained when a solution of pure alkali or ammonium salt of a polybasic acid, A = const., is titrated with strong acid of total concentration a5 ; (2) the curve obtained when the same solution as above is titrated with addition of a small amount of metal ions, B = const., the condition being B « A. The difference (,1,) of pH between the two curves at a0 = 0 is explained, exclusively as being an effect of the metal ions. There are three possible cases that should be taken into consideration: 1. /\u27:,. = O; The mixed hydroxo complexes are either not formed, or the initially hydrolyzed composite central group [B(OH)2] is not further hydrolyzed; Bjerrum\u27s method6 can be applied to find the p value. A thorium oxalate complex• is given as an example.2. /\u27:,. > O; OH ions from the initially hydrolysed composite central group, [B(OH)2] are replaced by the ligand. A zirconyl oxalato complex11 is given as an example. 3. /\u27:,. < O; Mixed hydroxo complexes are formed. Thorium maleato3 and thorium phthalato2 complexes are given as examples. In the cases 2. and 3., where Bjerrum\u27s method can not be applied, the solubility curve of metal hydroxide in an excess of ligand, can be used to find the p value

Model Studies of the Solubility of Inorganic Mercury in the Polluted Coastal Marine Environment

In order to determine the possible solubility of inorganic mercury in the polluted coastal marine environment, both experimental and model studies have been performed. Dissolution of HgS(s) in bicarbonate solutions of various concentrations and pH values showed increasing solubility of mercury with the pH and [C032-] increase. Approximately constant value of 40 μg dm-3 was obtained when HgS(s) was dissolved in various dilutions of sea water with NaHC03 of 10-3 mol dm-3• The model calculation shows that mercury in the presence of oxygen can be released from the sediments as elemental mercury, Hg0 (aq), wich is in equilibrium with volatile Hg0 (g). The rate at which oxidation proceeds is still unknown. Recent studies show that the solubility of inorganic and organic salts of mercury (II) are much higher than solubility of elemental mercury. From the experimental results and from the model calculation, one can predict continuous leaching of soluble mercury from polluted sediments long after polluting industries will be closed all over the world

Precipitation and Hydrolysis of Metallic Ions in Sea Water. I. Ionic State of Zirconium and Thorium in Sea Water

The tyndallometric method is a very suitable and promrsmg experimental method for the determination of solubility and precipitation in a broad concentration range. The critical concentrations of the precipitating components and the charge on the ions present in the solution in equilibrium with the solid phase can be determined. The precipitation diagrams of zirconium and thorium at 500/o sea water are shown. The influence of the sea water concentration on the solubility product K84 has been investigated for thorium. Both elements are, under sea water conditions, probably entirely hydrolized without charge. One could therefore expect very effective fixation of the studied elements on other solid particles and the surface in sea water

Precipitation and Hydrolysis of Thorium(IV) in Aqueous Solution. II. Influence of pH and Neutral Electrolytes upon the Precipi tation in the System Thorium Nitrate - Potassium Phthalate

The influence of the pH and other neutral electrolytes upon the precipitation and hydrolysis of thorium(IV) in aqueous solutions of thorium nitrate and potassium phthalate was investigated. A three-dimensional concentration tyndallogram in which turbidity has been plotted against the concentration of potassium phthalate and the pH, at constant concentration of Th(IV) 1.25 X 10-3M, shows various precipitation and dissolution regions of th e system. The following co ncentration regions were marked and discussed: the concentration region where sudden precipitation of thorium hydroxide occurs, the region of thorium hydroxide stable sols, the region of thorium phthalate sols, the region of unstable systems in which crystals appear after a few days\u27 aging and the region of stable clear solution at rathe r high pH values. The effect of neutral electrolytes upon the precipitation in the regio n of stable clear solution was investigated. It was d etermined that neutral electrolytes influence to a great extent the prec ipitation at the boundary of thorium phthalate precipitate (pH= 5)

Precipitation · and Hydrolysis of Thorium(IV) in Aqueous Solution: Thorium Nitrate - Potassium Hydroxide. I. Determination of Solubility Constants of Th(OH)4

The precipitation and h ydrolysis 0f thorium (IV) in aqueous solutions of thorium nitrate - potassium hydroxide was investigated at 20oc with a tyndallometel\u27.\u27 a nd a pH-meter. A three-dimensional precipitation diagram for a wide r ange of concentrations of both precipitating components was constructed. The concentration region of thorium hydroxide, the fast precipitation, the formation of sols and of stable clear solutions were observed. The decreased precipitation of thorium h ydroxide at pH between 9 - 10.4 is considered to be the effect of the carbonate ions present. By a very simple graphical tyndallometric method the solubility products of thorium hydroxide were directly determined as: log K so = - 45.7; log Ks2 = - 24.3 and the cumulative hydrolytic constant */3 2 = 1.029 X 10-1 was calculated. The predominant hydrolytic species of thorium-ion in aqueous solution in equilibrium with the solid phase of Th(OH) 4 were estimated. The predominant species is the free ion Th4+ for pH 3.4 and [Th(OH)22+]n for the pH between 3.5 and 4.L At values lower pH 4.1 ionic species of thorium are formed with more than two OH- ions per one thorium ion

Concentration and localization of zinc during seed development and germination in wheat

In a field experiment, the effect of foliar Zn applications on the concentration of Zn in seeds of a bread wheat cultivar (Triticum aestivum L. cv. Balatilla) was studied during different stages of seed development. In addition, a staining method using dithizone (DTZ: diphenyl thiocarbazone) was applied to (1) study the localization of Zn in seeds, (2) follow the remobilization of Zn during germination, and (3) develop a rapid visual Zn screening method for seed and flour samples. In all seed development stages, foliar Zn treatments were effective in increasing seed Zn concentration. The highest Zn concentration in the seeds was found in the first stage of seed development (around the early milk stage); after this, seed Zn concentration gradually decreased until maturity. When reacting with Zn, DTZ forms a redcolored complex. The DTZ staining of seed samples revealed that Zn is predominantly located in the embryo and aleurone parts of the seeds. After 36 h of germination, the coleoptile and roots that emerged from seeds showed very intensive red color formation and had Zn concentrations up to 200 mg kg1, indicating a substantial remobilization of Zn from seed pools into the developing roots (radicle) and coleoptile. The DTZ staining method seems to be useful in ranking flour samples for their Zn concentrations. There was a close relationship between the seed Zn concentrations and spectral absorbance of the methanol extracts of the flour samples stained with DTZ. The results suggest that (1) accumulation of Zn in seeds is particularly high during early seed development, (2) Zn is concentrated in the embryo and aleurone parts, and (3) the DTZ staining method can be used as a rapid, semiquantitative method to estimate Zn concentrations of flour and seed samples and to screen genotypes for their Zn concentrations in seeds

SN2012ab: A Peculiar Type IIn Supernova with Aspherical Circumstellar Material

We present photometry, spectra, and spectropolarimetry of supernova (SN) 2012ab, mostly obtained over the course of $\sim 300$ days after discovery. SN 2012ab was a Type IIn (SN IIn) event discovered near the nucleus of spiral galaxy 2MASXJ12224762+0536247. While its light curve resembles that of SN 1998S, its spectral evolution does not. We see indications of CSM interaction in the strong intermediate-width emission features, the high luminosity (peak at absolute magnitude $M=-19.5$), and the lack of broad absorption features in the spectrum. The H$\alpha$ emission undergoes a peculiar transition. At early times it shows a broad blue emission wing out to $-14{,}000$ km $\mathrm{s^{-1}}$ and a truncated red wing. Then at late times ($>$ 100$\,$days) it shows a truncated blue wing and a very broad red emission wing out to roughly $+20{,}000$ km $\mathrm{s^{-1}}$. This late-time broad red wing probably arises in the reverse shock. Spectra also show an asymmetric intermediate-width H$\alpha$ component with stronger emission on the red side at late times. The evolution of the asymmetric profiles requires a density structure in the distant CSM that is highly aspherical. Our spectropolarimetric data also suggest asphericity with a strong continuum polarization of $\sim 1-3$% and depolarization in the H$\alpha$ line, indicating asphericity in the CSM at a level comparable to that in other SNe IIn. We estimate a mass-loss rate of $\dot{M} = 0.050\, {\rm M}_{\odot}\,\mathrm{yr^{-1}}$ for $v_{\rm pre} = 100$$\,$km$\,$$\mathrm{s^{-1}}$ extending back at least 75$\,$yr prior to the SN. The strong departure from axisymmetry in the CSM of SN 2012ab may suggest that the progenitor was an eccentric binary system undergoing eruptive mass loss.Comment: 18 pages, 12 figure

Prokineticin-1 (PROK1) modulates interleukin (IL)-11 expression via prokineticin receptor 1 (PROKR1) and the calcineurin/NFAT signalling pathway

Prokineticin-1 (PROK1) is a multifunctional secreted protein which signals via the G-protein coupled receptor, PROKR1. Previous data from our laboratory using a human genome survey microarray showed that PROK1–prokineticin receptor 1 (PROKR1) signalling regulates numerous genes important for establishment of early pregnancy, including the cytokine interleukin (IL)-11. Here, we have shown that PROK1–PROKR1 induces the expression of IL-11 in PROKR1 Ishikawa cells and first trimester decidua via the calcium–calcineurin signalling pathway in a guanine nucleotide-binding protein (Gq/11), extracellular signal-regulated kinases, Ca2+ and calcineurin–nuclear factor of activated T cells dependent manner. Conversely, treatment of human decidua with a lentiviral miRNA to abolish endogenous PROK1 expression results in a significant reduction in IL-11 expression and secretion. Importantly, we have also shown a regulatory role for the regulator of calcineurin 1 isoform 4 (RCAN1-4). Overexpression of RCAN1-4 in PROKR1 Ishikawa cells using an adenovirus leads to a reduction in PROK1 induced IL-11 indicating that RCAN1-4 is a negative regulator in the calcineurin-mediated signalling to IL-11. Finally, we have shown the potential for both autocrine and paracrine signalling in the human endometrium by co-localizing IL-11, IL-11Rα and PROKR1 within the stromal and glandular epithelial cells of non-pregnant endometrium and first trimester decidua. Overall we have identified and characterized the signalling components of a novel PROK1–PROKR1 signalling pathway regulating IL-11