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Effects of copyrolysis of sludge with calcium carbonate and calcium hydrogen phosphate on chemical stability of carbon and release of toxic elements in the resultant biochars.

The potential release of toxic elements and the stability of carbon in sludge-based biochars are important on their application in soil remediation and wastewater treatment. In this study, municipal sludge was co-pyrolyzed with calcium carbonate (CaCO) and calcium dihydrogen phosphate [Ca(HPO)] under 300 and 600 °C, respectively. The basic physicochemical properties of the resultant biochars were characterized and laboratory chemical oxidation and leaching experiments of toxic elements were conducted to evaluate the chemical stability of carbon in biochars and the potential release of toxic elements from biochars. Results show that the exogenous minerals changed the physico-chemical properties of the resultant biochars greatly. Biochars with exogenous minerals, especially Ca(HPO), decreased the release of Zn, Cr, Ni, Cu, Pb, and As and the release ratios were less than 1%. Tessier's sequential extraction analysis revealed that labile toxic elements were transferred to residual fraction in the biochars with high pyrolysis temperature (600 °C) and exogenous minerals. Low risks for biochar-bound Pb, Zn, Cd, As, Cr, and Cu were confirmed according to risk assessment code (RAC) while the potential ecological risk index (PERI) revealed that the exogenous Ca(HPO) significantly decreased the risks from considerable to moderate level. Moreover, the exogenous minerals significantly increased the chemical stability of carbon in 600 °C-pyrolyzed biochars by 10-20%. These results indicated that the copyrolysis of sludge with phosphate and carbonate, especially phosphate, were effective methods to prepare the sludge-based biochars with immobilized toxic elements and enhanced chemical stability of carbon.

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Ofloxacin CAS Number [824 Calcium carbonate CAS Num Eosin 5 isothiocyanate, R Potassium hydrogen carbon Calcium Stain Kit (Modif Calcium Stain Kit (Modif Androgen Receptor (Phosph Androgen Receptor (Phosph Amplite™ Fluorimetric H Amplite™ Intracellular Rabbit Anti-Human Androge Rabbit Anti-Human Androge

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Immobilizing Arsenic and Copper Ions in Manure Using a Nanocomposite.

Livestock manure (Man) commonly contains a certain quantity of heavy metal ions, such as arsenic (As) and copper (Cu) ions, resulting in a high risk on soil contamination. To solve this problem, heavy metal of manure was immobilized into sodium carbonate/biosilica/attapulgite composite (NaCO/BioSi/Attp), which was developed using a nanocomposite consisting of anhydrous sodium carbonate (NaCO), straw ash-based biochar and biosilica (BioSi), and attapulgite (Attp). When NaCO/BioSi/Attp was mixed with Man/AsCu, the obtained nanocomposite (NaCO/BioSi/Attp/Man/AsCu) with a porous nano-network structure could effectively control the release of As and Cu ions from manure through adsorption and chemical reaction. Meanwhile, a pot experiment indicated that NaCO/BioSi/Attp/Man/AsCu could increase the pH value of acid soil, promote the growth of rice, and significantly decrease the uptake of As and Cu ions by rice. Therefore, this work provides a promising approach to immobilize heavy metal ions in manure and, thus, lower the contamination risk to the environment. NaCO, BioSi, and Attp powders were mixed evenly with a weight ratio of W/W/W = 3:1:2.

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Amorphous calcium carbonate particles form coral skeletons.

Do corals form their skeletons by precipitation from solution or by attachment of amorphous precursor particles as observed in other minerals and biominerals? The classical model assumes precipitation in contrast with observed "vital effects," that is, deviations from elemental and isotopic compositions at thermodynamic equilibrium. Here, we show direct spectromicroscopy evidence in corals that two amorphous precursors exist, one hydrated and one anhydrous amorphous calcium carbonate (ACC); that these are formed in the tissue as 400-nm particles; and that they attach to the surface of coral skeletons, remain amorphous for hours, and finally, crystallize into aragonite (CaCO). We show in both coral and synthetic aragonite spherulites that crystal growth by attachment of ACC particles is more than 100 times faster than ion-by-ion growth from solution. Fast growth provides a distinct physiological advantage to corals in the rigors of the reef, a crowded and fiercely competitive ecosystem. Corals are affected by warming-induced bleaching and postmortem dissolution, but the finding here that ACC particles are formed inside tissue may make coral skeleton formation less susceptible to ocean acidification than previously assumed. If this is how other corals form their skeletons, perhaps this is how a few corals survived past CO increases, such as the Paleocene-Eocene Thermal Maximum that occurred 56 Mya.

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Calcium carbonate CAS Num Cellufine Formyl , 50 ml Cellufine Formyl Media Cellufine Formyl , 500 ml Cellufine Formyl Media Cellufine Formyl Media Calcium Stain Kit (Modif Calcium Stain Kit (Modif Formalin Solution (20%) Formalin Solution (20%) Formalin Solution (20%) Formalin (10% Neutral Bu

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Double-coated enrofloxacin microparticles with chitosan and alginate: Preparation, characterization and taste-masking effect study.

Enrofloxacin (ENRO) is widely used as an antimicrobial drug for treatment of uncomplicated and complicated infections in veterinary medicine. Its bitter taste limits its clinical applications in veterinary. To mask the bitter taste of this drug, double-coated taste-masking microparticles of ENRO (DTME) were prepared through stearic acid solid dispersion and chitosan-alginate microparticle coating technologies. The taste-masking effect was evaluated by pig feeding experiment. Results showed that DTME exhibited a spherical-like shape (170490μm). DTME yielded a drug loading rate of DTME 20.3% and an entrapment efficiency of 89.8%. The bitter detection threshold value of ENRO for pigs is 2μg/mL. The drug release amounts of DTME within 30s were less than 2μg/mL in artificial saliva. Compared with normal food intake, the food intake of pigs decreased 28.65% when fed with fodder containing free ENRO and slightly increased (0.18%) when fed with fodder containing DTME. Therefore, DTME masked the bitterness of ENRO and improved its palatability. In conclusion, DTME showed satisfactory bitter taste-masking property; this novel formulation was likely to provide more selectable dosage forms for ENRO.

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DFT Calculations with van der Waals Interactions of Hydrated Calcium Carbonate Crystals CaCO3·(H2O, 6H2O): Structural, Electronic, Optical, and Vibrational Properties.

The role of hydration on the structural, electronic, optical, and vibrational properties of monohydrated (CaCO3·H2O, hexagonal, P31, Z = 9) and hexahydrated (CaCO3·6H2O, monoclinic, C2/c, Z = 4) calcite crystals is assessed with the help of published experimental and theoretical data applying density functional theory within the generalized gradient approximation and a dispersion correction scheme. We show that the presence of water increases the main band gap of monohydrocalcite by 0.4 eV relative to the anhydrous structure, although practically not changing the hexahydrocalcite band gap. The gap type, however, is modified from indirect to direct as one switches from the monohydrated to the hexahydrated crystal. A good agreement was obtained between the simulated vibrational infrared and Raman spectra and the experimental data, with an infrared signature of hexahydrocalcite relative to monohydrocalcite being observed at 837 cm(-1). Other important vibrational signatures of the lattice, water molecules, and CO3(2-) were identified as well. Analysis of the phonon dispersion curves shows that, as the hydration level of calcite increases, the longitudinal optical-transverse optical phonon splitting becomes smaller. The thermodynamics properties of hexahydrocalcite as a function of temperature resemble closely those of calcite, while monohydrocalcite exhibits a very distinct behavior.

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Calcium carbonate CAS Num Calcium Stain Kit (Modif Calcium Stain Kit (Modif HIV type O envelope antig Dermorphin - CELLKINES PLATELET DERIVE PLATELET DERIVED GROWTH F CELLKINES PLATELET DERIVE PLATELET DERIVED GROWTH F Human Brain Derived Neuro Human Glial Derived Neuro Human Stromal Cell-Derive

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The effect of Mg(2+) incorporation on the structure of calcium carbonate clusters: investigation by the anharmonic downward distortion following method.

Mg(2+) is considered to play an important role in the formation of calcium carbonate polymorphs; however, how it affects polymorph selection during the early stages of CaCO3 formation is not yet well understood. In the present study, in order to clarify the effect of Mg(2+) on the nucleation of calcium carbonate polymorphs, the stable structures of anhydrous additive-free and Mg-containing calcium carbonate clusters are derived using the anharmonic downward distortion following method, based on quantum chemical calculations. Optimization is performed at the B3LYP/6-31+G(d) level and the solvent effect is induced by the self-consistent reaction field method using the conductor-like polarized continuum calculation model. Calculation results show that incorporating Mg(2+) into clusters can change the clusters' stable configuration. In the case of dimers and trimers, a Mg ion strongly prefers to locate at the centre of the clusters, which suggests that Mg is easy to incorporate into the clusters once it is released from its tight hydration shell. Notably, structures similar to the crystalline phase appear when only four CaCO3 units aggregate into the cluster: in the stable structure of the additive-free CaCO3 tetramer, the arrangement of Ca and CO3 ions is almost the same as that of the calcite structure, while the structure of the Mg-containing CaCO3 tetramer resembles the aragonite structure in the way that CO3 ions are stacked. These results indicate that Mg can play a key role in aragonite formation not only by inhibiting calcite growth but also by directly promoting aragonite nucleation in the early stages of CaCO3 formation.

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Fabrication of bone cement that fully transforms to carbonate apatite.

The objective of this study was to fabricate a type of bone cement that could fully transform to carbonate apatite (CO3Ap) in physiological conditions. A combination of calcium carbonate (CaCO3) and dicalcium phosphate anhydrous was chosen as the powder phase and mixed with one of three kinds of sodium phosphate solutions: NaH2PO4, Na2HPO4, or Na3PO4. The cement that fully transformed to CO3Ap was fabricated using vaterite, instead of calcite, as a CaCO3 source. Their stability in aqueous solutions was different, regardless of the type of sodium phosphate solution. Rate of transformation to CO3Ap in descending order was Na3PO4>Na2HPO4>NaH2PO4. Transformation rate could be affected by the pH of solution. Results of this study showed that it was advantageous to use vaterite to fabricate CO3Ap-forming cement.

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Magnesium Contamination in Soil at a Magnesite Mining Region of Liaoning Province, China.

Magnesite is the world's most important source material for magnesia refractory production, and Haicheng City in Liaoning Province, China has been called "the magnesium capital of the world." However, magnesite mining in these areas has caused serious environmental problems. Field investigations have shown that the soil profile of many sites in the mining region are contaminated by magnesium, and the magnesium-enriched crusts that have formed on the soil surface have affected ecologically important soil functions, particularly reduced water penetration rate. Laboratory experiment revealed that anionic polyacrylamide and calcium dihydrogen phosphate can be used to improve soil condition, and have positive effects on soil function. The findings of this study are of significance in the magnetite mining areas, providing clear options for the remediation of soils that should be carried out immediately.

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Catanionic surfactant-assisted mineralization and structural properties of single-crystal-like vaterite hexagonal bifrustums.

Crystalline vaterite is the most thermodynamically unstable polymorph of anhydrous calcium carbonate (CaCO3), and various morphologies can be controlled in the presence of organic additives. Constructing vaterite with minimal defects, determining its distinctive properties, and understanding the formation mechanism behind a biomimetic process are the main challenges in this field. In this paper, a unique single-crystal-like vaterite hexagonal bifrustum with two hexagonal and 12 trapezoidal faces has been fabricated through a catanionic surfactant-assisted mineralization approach for the first time. Compared with the polycrystalline vaterite aggregates, these bifrustums clearly present a doublet for Raman v1 symmetric stretching mode, a low depolarizaiton ratio for carbonate molecular symmetry, and a high structural stability. These indicate a dominant position of hexagonal phase in each crystallite and confirm the Raman v1 doublet characteristics of synthetic and biomineral-based vaterites. Our finding may provide evidence to distinguish vaterite with different structures and shed light on a possible formation mechanism of vaterite single crystals.

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A mineralogical characterization of biogenic calcium carbonates precipitated by heterotrophic bacteria isolated from cryophilic polar regions.

Precipitation of calcium carbonate (CaCO3(s) ) can be driven by microbial activity. Here, a systematic approach is used to identify the morphological and mineralogical characteristics of CaCO3(s) precipitated during the heterotrophic growth of micro-organisms isolated from polar environments. Focus was placed on establishing mineralogical features that are common in bioliths formed during heterotrophic activity, while in parallel identifying features that are specific to bioliths precipitated by certain microbial phylotypes. Twenty microbial isolates that precipitated macroscopic CaCO3(s) when grown on B4 media supplemented with calcium acetate or calcium citrate were identified. A multimethod approach, including scanning electron microscopy, high-resolution transmission electron microscopy, and micro-X-ray diffraction (μ-XRD), was used to characterize CaCO3(s) precipitates. Scanning and transmission electron microscopy showed that complete CaCO3(s) crystal encrustation of Arthrobacter sp. cells was common, while encrustation of Rhodococcus sp. cells did not occur. Several euhedral and anhedral mineral formations including disphenoid-like epitaxial plates, rhomboid-like aggregates with epitaxial rhombs, and spherulite aggregates were observed. While phylotype could not be linked to specific mineral formations, isolates tended to precipitate either euhedral or anhedral minerals, but not both. Three anhydrous CaCO3(s) polymorphs (calcite, aragonite, and vaterite) were identified by μ-XRD, and calcite and aragonite were also identified based on TEM lattice-fringe d value measurements. The presence of certain polymorphs was not indicative of biogenic origin, although several mineralogical features such as crystal-encrusted bacterial cells, or casts of bacterial cells embedded in mesocrystals are an indication of biogenic origin. In addition, some features such as the formation of vaterite and bacterial entombment appear to be linked to certain phylotypes. Identifying phylotypes consistent with certain mineralogical features is the first step toward discovering a link between these crystal features and the precise underlying molecular biology of the organism precipitating them.

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