Preparation of a Resorbable Osteoinductive Tricalcium Phosphate Ceramic

Over the past decade we have demonstrated numerous times that calcium phosphates can be rendered with osteoinductive properties by introducing specific surface microstructures1. Since most of these calcium phosphates contained hydroxyapatite, they are either slowly or not resorbable2. Resorbability is an often sought after characteristic of calcium phosphates so that they can be gradually replaced by newly formed bone. The objective of this study was to prepare a resorbable surface microstructured tricalcium phosphate (TCP) ceramic and evaluate its osteoinductive property and resorption rate after intramuscular implantation in dogs. This material was then compared to the established and slowly resorbable osteoinductive biphasic calcium phosphate ceramic (BCP)

Adsorbent phosphates

An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given

Synergy between conventional phosphorus fire retardants and organically-modified clays can lead to fire retardancy of styrenics

Polystyrene–clay nanocomposites combined with phosphorous-containing fire retardants have been prepared and used to explore the thermal stability and mechanical properties of the polymer formed. The amounts of fire retardants and clay used were varied to study the effect of each on thermal stability and mechanical properties of the polymer. The samples were prepared by bulk polymerization and analyzed by X-ray diffraction, thermogravimetric analysis, cone calorimetry, Fourier Transform infrared spectroscopy and the evaluation of mechanical properties. The thermal stability of the polymers is enhanced by the presence of the phosphorus-containing fire retardants

Characterization of GDP-mannose Pyrophosphorylase from Escherichia Coli O157:H7 EDL933 and Its Broad Substrate Specificity

GDP-mannose pyrophosphorylase gene (ManC) of Escherichia coli (E. coli) O157 was cloned and expressed as a highly soluble protein in E. coli BL21 (DE3). The enzyme was subsequently purified using hydrophobic and ion exchange chromatographies. ManC showed very broad substrate specificities for four nucleotides and various hexose-1-phosphates, yielding ADP-mannose, CDP-mannose, UDP-mannose, GDP-mannose, GDP-glucose and GDP-2-deoxy-glucose

Bio-precipitation of uranium by two bacterial isolates recovered from extreme environments as estimated by potentiometric titration, TEM and X-ray absorption spectroscopic analyses

This is the post-print version of the final paper published in Journal of Hazardous Materials. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This work describes the mechanisms of uranium biomineralization at acidic conditions by Bacillus sphaericus JG-7B and Sphingomonas sp. S15-S1 both recovered from extreme environments. The U–bacterial interaction experiments were performed at low pH values (2.0–4.5) where the uranium aqueous speciation is dominated by highly mobile uranyl ions. X-ray absorption spectroscopy (XAS) showed that the cells of the studied strains precipitated uranium at pH 3.0 and 4.5 as a uranium phosphate mineral phase belonging to the meta-autunite group. Transmission electron microscopic (TEM) analyses showed strain-specific localization of the uranium precipitates. In the case of B. sphaericus JG-7B, the U(VI) precipitate was bound to the cell wall. Whereas for Sphingomonas sp. S15-S1, the U(VI) precipitates were observed both on the cell surface and intracellularly. The observed U(VI) biomineralization was associated with the activity of indigenous acid phosphatase detected at these pH values in the absence of an organic phosphate substrate. The biomineralization of uranium was not observed at pH 2.0, and U(VI) formed complexes with organophosphate ligands from the cells. This study increases the number of bacterial strains that have been demonstrated to precipitate uranium phosphates at acidic conditions via the activity of acid phosphatase

A tale of two inositol trisphosphates.

Between spring 1982 and autumn 1984 the physiological role of Ins(1,4,5)P3 as a calcium-mobilizing second messenger was first suggested and then experimentally established. At the same time the unexpected complexity of inositide metabolism began to be exposed by the discovery of Ins(1,3,4)P3. This article recalls my entanglement with these two inositol phosphates

Removal and Reuse of Phosphorus as a Fertilizer from CAFO Runoff

Eutrophication is the process in which nutrient saturated waters promote algal blooms on the surface of the water. This limits the amount of dissolved oxygen content in the water, effectively limiting the range of species that can survive in a body of water. Concentrated animal feeding operations (CAFO) can contribute to this issue. The animals in a CAFO produce large amounts of nutrient-rich waste streams that can enter natural waterways if not properly managed and increase the problem of eutrophication. The ability to treat these waste streams and recover the excess nutrients would allow for not only the reduction of nutrient leaching and runoff but would help create sustainable phosphorus practice. Phosphorus is vital in terms of food production, and there is no replacement for phosphorus for plants or humans. As the population continues to increase, food demand will as well. This means that at any point that phosphorus can be recovered, it should be. To recover phosphorus effectively from waste water sources, reverse osmosis, anion exchange, or adsorption are all viable options. Woo Pig Pooie researched these options for recovering phosphorus, and adsorption was found to be the most promising from standpoints of low maintenance and cost effectiveness. Multiple adsorption materials were ranked based on appropriate performance of cost, particle size, adsorption qualities, and the effects of application of the material. Water treatment residuals, WTR (i.e. spent alum from a drinking water treatment plant), was determined to be the most effective adsorbent. WTR, a waste product, is 80% water as it exits the water treatment plant. It must be pelletized and dried before use as an adsorbent. Pelletized and dried WTR was utilized in a full-scale facility treating 62 GPM of feed using two 11,000 gallons packed columns with associated equipment. If the cost of pelletizing and drying the WTR is included, an alternative strategy for implementation on individual farms is for several farmers to form a cooperative, which would allow the minimization of the $1,460,000 fixed capital cost and the$504,000 cost of manufacturing of the drying pelletizing facility. This would allow for the maximum amount of WTR to be treated increasing the revenue of the operation to $731,500. The cooperative would have an operation of 10 years with a net present value of$5,000. Experimental results using WTR packed columns have shown non-detectable levels of phosphorus in the effluent. The produced phosphorus saturated WTR could be land applied to reduce the level of nutrients in runoff from fields, making a safer agriculture operation

Chemical Diversity of Apatites

Apatites can accommodate a large number of vacancies and afford multiple ionic substitutions determining their reactivity and biological properties. Unlike other biominerals they offer a unique adaptability to various biological functions. The diversity of apatites is essentially related to their structure and to their mode of formation. Special charge compensation mechanisms allow molecular insertions and ion substitutions and determine to some extent their solubility behaviour. Apatite formation at physiological pH involves a structured surface hydrated layer nourishing the development of apatite domains. This surface layer contains relatively mobile and exchangeable ions, and is mainly responsible for the surface properties of apatite crystals from a chemical (dissolution properties, ion exchange ability, ion insertions, molecule adsorption and insertions) and a physical (surface charge, interfacial energy) point of view. These characteristics are used by living organisms and can also be exploited in material science

Phytic acid degradation by phytase – as viewed by 31P NMR and multivariate curve resolution

The 31P NMR method is a most direct and useful method to describe the degradation of phytic acid to lower inositol phosphates by the action of the enzyme phytase. The use of chemometric and CARS visualizes and helps in the interpretation of the results. By means of LatentiX it has been possible to visualize the time-dependent hydrolysis of phytic acid and by PCA the complexity of the phytic acid is shown in the score plots. By modeling the spectra in CARS it is possible to identify and quantify each of the inositol phosphates