Absorption Of Cobalt Research Articles

Shining a light on Co(terpyridine)2 complexes: Unravelling the impact of ligand substitution at the 4’-position on optical and electrochemical properties through experimental and theoretical investigations

The present work involves synthesis, characterisation and study of absorption, emission and electrochemical properties of cobalt(III) bis-terpyridine complexes with varying substituent at the 4’-position of the central pyridine ring of terpyridine moiety. The work clearly demonstrates the modulation of the light harvesting window with changing the substituent viz. phenyl, naphthalenyl and thienyltriphenylamine. The naphthalenylterpyridine based cobalt complex shows considerable room temperature luminescence. Cyclic voltammetry data of the complexes reveal a reversible CoIII/II based redox feature. DFT based structure optimisations for all the complexes were performed at the B3LYP level using 6-31G (d,p) and LANL2DZ basis sets. TD-DFT based theoretical calculations were performed with the optimised structures to simulate the experimental absorption spectrum for all the complexes and hence the electronic transitions for the observed absorption peaks were assigned.

The Content of Heavy Metals, Arsenic, and Aluminum in Mint Leaves and Products

Mint is a medicinal herbal drug; and its leaves are also widely used in the food and cosmetic industries. Medical literature states that mint is naturally resistant to toxic elements and capable of accumulating them in significant amounts.The aim of the study was to compare heavy metals, arsenic, and aluminum contents in mint leaves and products.Materials and methods: the study covered peppermint leaves, tinctures, and oils, as well as teas and dietary supplements made of different varieties of mint. Elemental analysis was performed according to the procedure of inductively coupled plasma mass spectrometry (ICP-MS) developed by the authors.Results: the authors studied the compliance of the experimentally established contents of heavy metals, arsenic, and aluminum in peppermint leaves and products to the requirements of Russian and foreign regulatory documentation. Nonparametric Spearman correlation coefficients were calculated to characterise the interaction between chemical elements.Conclusions: arsenic contents in mint leaves may exceed the limit given in the State Pharmacopoeia of the Russian Federation, 14th ed. It is supposed that the increased contents are not a result of the anthropogenic factor, but a specific characteristic of this plant. The study demonstrated synergistic absorption of aluminum, iron, and vanadium, as well as copper and zinc by mint. It was established that manganese had an antagonistic effect on the absorption of nickel, lead, and cobalt by mint.

Crystallographic and (spectro)electrochemical characterizations of cobalt(II) 10-phenyl-5,15-di-p-tolylporphyrin

The synthesis, cyclic and rotating disk electrode voltammograms, UV-visible absorption and X-ray diffraction analyses of cobalt(II) 10-phenyl-5,15-di-p-tolylporphyrin (1-Co) are described. 1-Co was crystallized by slow diffusion of n-hexane into a concentrated CH2Cl2 solution. X-ray diffraction analyses reveals porphyrin aromatic cycle stacking in the crystal, C-H···π interactions of the CH2Cl2 solvent with the π-system of one tolyl group and Co(II)···π (porphyrin ring) interactions. The abstraction of 1.0 F/mol during the electrolysis at the first oxidation potential was followed by spectroelectrochemistry. It leads to the Co(II) → Co(III) transformation rather than the formation of the cation radical of the porphyrin ligand. These results were supported by comparison of the cyclic and rotating disc electrode voltammograms, of the UV-Visible absorption spectra, before and after electrolysis of 1-Co.

Computational DFT calculations, photovoltaic properties and synthesis of (2R, 3S)-2, 3, 4-trihydroxybutoxy substituted phthalocyanines

In this study, 4-((2R, 3S)-2, 3, 4-trihydroxybutoxy) phthalonitrile was synthesized and characterized as starting material. This new starting material reacts with cobalt and copper metal salts to obtain metallophthalocyanine complexes. The electronic absorption of cobalt and copper phthalocyanine compounds in different concentrations of THF was investigated. In addition, the solubility and absorption of the compounds in different solvents were investigated. Density functional theory was also performed to support the relevant experimental results of the synthesized copper and cobalt center atomic compound. The photovoltaic performance of compounds was measured as current density–voltage (J–V).

Effect of corn lectins on the intestinal transport of trace elements

The absorption of iron, copper, zinc, and cobalt deriving from the diet and supplements varies, depending on the form of these trace elements and the presence of absorption inhibitors. The objective of this study was to examine the absorption of iron, copper, zinc, and cobalt in the presence of corn lectin as a possible inhibitor of intestinal absorption. The highest level of inhibition was shown in bull in vitro intestinal segments: incubation with corn lectins reduced the absorption of copper by 35.5%, of zinc by 28%, and of cobalt by 17.3%. It caused no observable effect on iron absorption. The addition of N-acetylgalactosamine neutralised the inhibitory effect of corn lectins and restored the absorption of the trace elements. The levels of copper and iron in the blood of rats receiving a diet supplemented with lyophilized corn lectins, decreased by 11.3% and 16.4%, respectively. Our results thus suggest that corn lectins may act as absorption inhibitors of iron, copper, zinc, and cobalt, most likely through blocking the transport of elements across the apical membrane of enterocytes. The present study suggests that individuals should consider their trace element status if their diet includes high amounts of raw corn. However, additional in vivo studies are required to confirm these results.

Cross-section determination for one- and two-photon absorption of cobalt at hard-x-ray energies

For incident x-ray energies below the core level ionization threshold, one-photon absorption (OPA) leads to off-resonant x-ray excitations that are mediated by a virtual intermediate electronic state. In the linear regime of x-ray interaction, this intermediate state may decay radiatively and the maximum energy of the emitted photon is given by the initial and final atomic state as well as the energy of the incident photon. In the nonlinear excitation regime, however, this intermediate state may be depleted by a second x-ray absorption process as described in the sequential two-photon absorption (TPA) mechanism. Since the same intermediate state is involved in the OPA and TPA processes, the cross-section values for OPA and TPA are interconnected. We report on the determination of cross-section values for off-resonant excitation conditions, and show how the data can be used for estimating the TPA cross section in the sequential absorption mechanism. The determined off-resonant cross sections for cobalt exhibit a Lorentz-like energy-dependent behavior allowing for an energy-dependent description of the OPA and TPA cross sections with semiempirical models. The dependence of TPA cross sections on atomic number is discussed and different scaling laws are investigated. The effect of the lifetimes of a virtual intermediate state is also studied in relation to the incidence x-ray energy.

Effect of vitamin B12 and taurine on the alleviation of nutritional anaemia in common sole (Solea solea)

Sole fed commercial pellets develop a nutritional anaemia. This study assessed the impact of dietary B12 and taurine on the haematocrit (Hct) and haemoglobin (Hb) level and mineral absorption in anaemic sole. Anaemic sole was fed one of four diets. Diets were equal regarding mineral, amino acid and macronutrient composition and formulated, according to a two by two factorial design: two B12 (0.34 vs. 1.9 mg kg dm⁻¹) and two taurine levels (3.5 vs. 7.6 mg kg dm⁻¹). The feeding level was restricted and equal for all diets. Hct and Hb levels in anaemic sole are influenced by dietary B12. A “high” level of B12 increases the Hct and Hb level. An increasing level of taurine suppresses the stimulating effect of the “high” level of B12. The applied B12 and taurine levels were unable to completely alleviate the anaemia in sole. Nevertheless, sole needs high dietary levels of B12 to alleviate anaemia. The impact of B12 and taurine on Hb and Hct was not related to a change in the absorption of iron. A “high” level of B12 positively affected the absorption of chromium and a high level of taurine negatively affected the absorption of cobalt in sole.

Leafy Vegetables as Potential Pathways to Heavy Metal Hazards

The effect of anthropogenic activity relating to industrial and economic development has had a detrimental impact on the environment and human health, and hence the need for continued research. Five common African vegetables—Murraya koenigii, Ocimum gratissimum, Amaranthus hybridus, Capsicum annuum and Moringa oleifera were used to study absorption of Lead, Cadmium, Cobalt and Zinc from soils inoculated with metal ions. 0.1 M and 0.5 M solutions of the metal ions were used in the inoculation. Each of the plants was collected in the first instance at 8 weeks, and then at 10 weeks of inoculating. Atomic Absorption spectrophotometer was used to determine the metal ions concentrations absorbed in the plants. Cd2+ was most and Moringa oleifera the least absorbed of the four metal ions, with a highest value of 34.801 ± 0.805 mg/kg occurring in Capsicum annuum. Co2+ was the least absorbed of the four metal ions, Amaranthus hybridus showed highest absorption of Co2+ with mean absorption values of 5.566 ± 0.324 mg/kg and 5.670 ± 0.210 mg/kg for 0.1 M and 0.5 M solution of Co2+ respectively. Ocimum gratissimum absorbed Pb2+ most with the highest mean absorption of 5.290 ± 0.180 mg/kg and 6.354 ± 0.366 mg/kg for 0.1 M and 0.5 M respectively. Absorption increased as the concentration of the inoculant solution increased for all the plants, and decreased on moving from 8 weeks’ to 10 weeks’ for all the plants except Moringa oleifera. This could as a result of Phytovolatilization against the report of Padmavathiamma and Li, 2007 [1] that phytovolatilization occurs in As, Hg and Se. Ocimum gratissimum showed highest absorption with the mean value of 9.334 ± 0.312 mg/kg, when the inoculants concentration increased to 0.5 M, Capsicum annuum showed highest absorption with mean absorption value of 9.916 ± 0.614 mg/kg at 10th week. Also absorption increased as the concentration of the inoculant solution increased, and also on moving from 8 weeks’ to 10 weeks’ for all the plants. From the results obtained, all the vegetables absorbed significant amounts of the metal ions. This raises a lot of health concern about the vegetables consumed in most developing countries like Nigeria where vegetables are grown anywhere, without any consideration of the environment.

The effect of pulse-reverse electroplating bath temperature on the wear/corrosion response of Ni-Co/tungsten carbide nanocomposite coating during layer deposition

In this article, the effect of bath temperature during layer deposition on the electrochemical/abrasion responses of Ni-Co/tungsten carbide nanocomposite coating has been investigated. The Ni-Co/tungsten carbide nanocomposite coating was obtained using simultaneous deposition of tungsten carbide nanoparticles in three Ni-Co bath temperatures of 20, 40, and 60 °C. Afterwards, in order to characterize the obtained coatings, Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM), X-Ray diffraction (XRD), MAP analysis, potentiodynamic polarization and electrochemical impedance spectroscopy methods in 3.5 wt% NaCl, and also abrasion test using a pin on disc method were carried out. The results of this study revealed that the deposition obtained from Ni-Co bath contains tungsten carbide nanoparticles and results in strong (200) and hard (111) textures in the coating at different temperatures. Also increasing the bath temperature from 20 to 40 °C results in the absorption of cobalt and tungsten carbide nanoparticles, as well as reducing the nickel content and corrosion resistance in the coating, and on one hand it increases the abrasion resistance of the coating. However, a bath-temperature increase from 40 to 60 °C results in reducing the absorption of cobalt and tungsten carbide nanoparticles, and increasing the nickel content and corrosion resistance in the coating as well as reducing the abrasion resistance of the coating.

EFFECTS ON THE MINERAL COMPOSITION OF FLEISCHMANN’S YEAST (Saccharomyces cerevisiae) FERMENTING SUGAR-CANE JUICE CONTAMINATED WITH COBALT

The current work aimed to study the accumulation and the effects of cobalt on themineral composition of Fleischmann’s yeast Saccharomyces cerevisiae fermentingsugarcane juice with controlled contamination, in sub-toxic levels of cobalt. Thesterilized juice (120°C, 20 minutes), with 12% of total reducing sugars (TRS) and fourlevels of pH (3.5; 4.5; 5.5 and 6.5) was added with cobalt chloride salt (CoCl2.6H2O)resulting in six levels of contamination (0.0; 0.1; 0.5; 1.0; 2.0 e 5.0 mg Co L-1) and 24treatments. The juice inoculation was carried out with bread yeast (10% p/p). Afterthe end of the fermentation (6 hours), the fermented media were centrifuged, and thecellular viability, budding rate and levels of cobalt, phosphorus, calcium, magnesium,sulfur, copper, iron, manganese, potassium and zinc were determined (in dry weight– dw). The absorption of cobalt was influenced by the pH. This absorption was higherin pH 3.5, whereas in pH 6.5 we found almost no absorption. The levels ofpotassium, calcium, zinc and phosphorus decreased with the increase of pH whilethe levels of sulfur content increased. No significant differences could be observed inthe fermentative velocity for the several treatments.

EPR, Optical Absorption and FTIR Properties of Cobalt Doped Lithium Borophosphate Glass System

EPR, Optical Absorption and FTIR Properties of Cobalt Doped Lithium Borophosphate Glass System

Effect of different iron sources on the alleviation of nutritional anaemia in common sole (Solea solea)

Sole fed commercial pellets suffers from a nutritional anaemia. The hypotheses tested are: (1) the nutritional anaemia in sole fed commercial pellets is caused by an iron deficiency; (2) the assumed iron deficiency is due to inadequate absorption of iron; (3) an increase in absorption due to a higher bioavailability of heme or iron chelates will alleviate anaemia in sole and (4) haematocrit (Hct) and haemoglobin (Hb) are expected to follow the iron absorption patterns. In addition, we estimated the absorption of copper, cobalt, chromium, manganese, molybdenum and zinc in order to evaluate possible interaction between available iron sources and the absorption of other divalent minerals.Sole were fed four diets, each with a different iron source: iron sulphate, iron methionate, iron proteinate or heme. Feeding was restricted and equal for all diets. At the start of the experiment, sole reared on commercial pellets had average values of Hct, Hb and the hepatosomatic index of 12.5%, 19.6g.l−1 and 1.13%, respectively. The values at the end of the experiment did not differ from the values at the start and were not affected by the source of iron. The apparent absorption coefficients (AAC) of iron, manganese, zinc, cobalt, chromium and molybdenum, except for copper, were unaffected by the iron sources. Yet, the iron absorption was high for all sources tested. The AAC of copper was 15–22% higher in sole fed the diet with heme. The use of the different iron sources, including heme, did not affect Hct and Hb in anaemic sole. The high absorption of iron and copper in sole fed heme did not affect Hct and Hb, which suggests that the nutritional anaemia in sole is not an iron nor a copper deficiency anaemia. Statement of relevanceHigh, this study tested iron sources and their effect on mineral absorption, haematocrit and haemoglobin in anaemic sole. Absorption data of minerals in anaemic sole is novel. The high absorption of iron and copper in sole fed heme did not affect haematocrit and haemoglobin, which suggests the nutritional anaemia in sole is not an iron nor a copper deficiency anaemia.

Multimineral and Organic Composition of a Liquid By-Product from the Pyrobituminous Shale Pyrolysis Process and its Potential Use in Agriculture

Pyrolysis of pyrobituminous shale rock to extract products such as fuel oil and gas generate a liquid by-product called shale water (SW). In this study, the physical-chemical characterization of SW was performed and the effects on plant growth, mineral nutrition, and food safety were evaluated when applied via foliar in lettuce crop. Shale water showed a great diversity of organic compounds, minerals, and trace elements. The application of SW in lettuce resulted in no phytotoxic effect or accumulation of toxic elements to human health within the doses tested, and increased yield and the accumulation of several mineral nutrients in the leaves. The absorption and accumulation of zinc, copper, cobalt, molybdenum, and manganese was also improved when these minerals were applied together with SW. These results suggest that SW plays a role as a biostimulant and could be used in agriculture as a safety alternative to increase yield and biofortify crops.

Interdependence between urinary cobalt concentrations and hemoglobin levels in pregnant women

Cobalt is an essential trace element but may cause toxic effects upon occupational or environmental exposure. Women accumulate more cobalt than men at similar exposure levels which may be related to higher metabolic iron loss. During pregnancy these losses are much stronger but their influence on cobalt intake has not been studied. We have studied the associations between changes in hemoglobin and cobalt urinary excretion during pregnancy. 391 pairs of urine and blood samples from pregnant women were collected during the 12th and 32nd weeks of pregnancy and were analyzed for cobalt and hemoglobin. Mean concentrations of urinary cobalt were 0.73 and 1.6µg/g creatinine during the first and third trimesters, respectively (p<0.001). 84% of pregnant women had higher levels of cobalt in the third than in the first trimester. Cobalt concentrations were negatively associated to hemoglobin levels in the third trimester (p<0.05). Women with higher iron decreases between both trimesters had significant cobalt increases between these two periods. This correspondence involved a statistically significant difference in third trimester mean cobalt concentrations of anemic and non-anemic women, 1.8 and 1.5µg/g creatinine, respectively (p<0.05). No significant differences between these two groups were found during the first trimester. These results were used to construct generalized additive models both in normal and anemic women. The strong association between the changes of both iron status and cobalt urine levels found in pregnant women may be related to higher intestinal absorption of cobalt at iron depletion such as in the last pregnancy period when iron body demands are high. Possible toxicity effects of these cobalt increases along pregnancy should be considered in cases of populations occupationally or environmentally exposed to this metal.

Absorption and Electrochemical Properties of Cobalt and Iron Phthalocyanines and Their Quaternized Derivatives: Aggregation Equilibrium and Oxygen Reduction Electrocatalysis

The synthesis and investigation of the electronic properties of Co(II) and Fe(II)tetrakis(pyridine-3-yloxy)phthalocyanines, as well as the respective quaternized complexes, are reported here. After quaternization reaction, the compounds showed increased solubility in water, and their aggregation equilibrium was analyzed by varying the solution concentration, pH, and composition. Cyclic voltammograms of the four compounds showed both metal and ring centered redox processes, with the former being highly sensitive to methylation of the pyridyl groups. The catalytic effect of the phthalocyanines adsorbed on glassy carbon electrodes in the oxygen reduction reaction (ORR) was investigated by cyclic voltammetry (CV) and rotating disk voltammetry (RDV). The highest catalytic activities were observed for the Fe(II) complexes in alkaline media, and a 2 + 2 mechanism, which consists of a first complete O2 to H2O2 process and a subsequent incomplete H2O2 to H2O process, is proposed.

Occupational exposure to cobalt is not associated with incipient signs of dilated cardiomyopathy in a Belgian refinery

BackgroundExcessive absorption of cobalt has been associated with cases of dilated cardiomyopathy in the past, but it is unclear whether occupationally exposed populations are at risk.ObjectiveTo assess the possible relationship...

Optical and luminescence properties of Co:AgCl0.2Br0.8 crystals and their potential applications as gain media for middle-infrared lasers

Infrared absorption and luminescence emission of cobalt doped silver halide crystals were investigated at room temperature and at low temperatures. A broad absorption band was observed in the near-infrared (1.4–2.5 µm) and a broad emission band in the middle-infrared (3.5–5.2 µm). The emission lifetime varied between 1.73 ms at low temperatures and 5 µs at room temperature. Based on the measured parameters and theoretical calculations, we believe that there is an excellent chance that these crystals would lase in the mid-IR. Moreover, it would be possible to extrude fibers from the crystals and obtain mid-IR fiber lasers.

Absorption, distribution and fate of cobalt in the germ free silkworm, Bombyx mori

Absorption, distribution and fate of cobalt in the germ free silkworm, Bombyx mori

Monitoring of cobalt(II) uptake and transformation in cells of the plant-associated soil bacterium Azospirillum brasilense using emission Mössbauer spectroscopy.

Interaction of cobalt(II) at micromolar concentrations with live cells of the plant-growth-promoting rhizobacterium Azospirillum brasilense (strain Sp245) and further transformations of the metal cation were monitored using 57Co emission Mössbauer spectroscopy (EMS). Cell suspensions of the bacterial culture (2.4 x 10(8) cells ml(-1)) were doped with radioactive 57CoCl2 (1 mCi; final concentration 2 x 10(-6) M 57Co2+), kept under physiological conditions for various periods of time (from 2 min up to 1 hour) and then rapidly frozen in liquid nitrogen. Analysis of emission Mössbauer spectra of the frozen aqueous suspensions of the bacterial cell samples shows that the primary absorption of cobalt(II) at micromolar concentrations by the bacterial cells is rapid and virtually complete, giving at least two major forms of cobalt(II) species bound to the cells. Within an hour, the metal is involved in further metabolic transformations reflected by changes occurring in the spectra. The Mössbauer parameters calculated from the EMS data by statistical treatment were different for suspensions of live and dead (thermally killed) bacterial cells that had been in contact with 57Co2+ for 1 h, as well as for the cell-free culture medium containing the same concentration of 57Co2+. Chemical after-effects of the nuclear transition (57Co --> 5 7Fe), which provide additional information on the chemical environment of metal ions, are also considered. The data presented demonstrate that EMS is a valuable tool for monitoring the chemical state of cobalt species in biological matter providing information at the atomic level in the course of its uptake and/or metabolic transformations.

In vitro percutaneous absorption of cobalt.

To evaluate skin absorption of cobalt powder in an in vitro system. Experiments with volunteers show that cobalt powder can permeate through the skin, but there are no data with regard to the mechanism or the amount of permeation. Skin permeation was calculated by the Franz diffusion cell method with human skin. A physiological solution was used as receiving phase and the cobalt powder was dispersed in synthetic sweat. The amount of metal passing through the skin was analysed by electro-thermal atomic absorption spectrometry (ETAAS). Parallel polarographic analysis (differential pulse polarography-DPP) allowed evaluation of cobalt present as ions (Co(2+)) in donor and receiving phases. Measurements of cobalt skin content were also performed. Evaluation of metal in the receiving phase allowed us to demonstrate the permeation of cobalt through the skin. Steady-state flow of percutaneous cobalt permeation was calculated as 0.0123+/-0.0054 microg cm(-2) h(-1), with a lag time of 1.55+/-0.71 h. The experiments show that cobalt powder can pass through the skin when applied as a dispersion in synthetic sweat, oxidising metallic cobalt into ions, which permeate the skin. These experiments show for the first time how cobalt can permeate the skin.