Search results for "phosphate"

Investigation on lithium/polymer electrolyte interface for high performance lithium rechargeable batteries

1997

Abstract Performance data of several linear and cross-linked polymer electrolytes are reported and the electrochemical criteria for the selection of electrolytes to be used in electric vehicle lithium metal batteries are discussed. Further, laboratory lithium cells with LiMn2O4 composite cathode were tested to ascertain the effective viability of these polymer in solid-state batteries and preliminary results are reported. This study clearly demonstrates the importance of a broad-based electrochemical characterization in selecting an electrolyte for lithium metal batteries.

Superexchange pathways in oxovanadium(IV) phosphates

1992

Abstract Oxovanadium(IV) phosphates show a diversity of magnetic behaviours that cannot be deduced from their respective structural features only. In part, this is due to the involvement of phosphate bridges in the spin transfer between V(IV) centres, and 31P solid state nuclear magnetic resonance becomes a key tool in determining the exchange mechanisms. The magnetic properties of a wide set of vanadium(IV) containing derivatives can be explained by realizing that a good overlap of the magnetic orbits may be achieved through paths involving phosphorus d orbitals.

Organization of Organic Molecules with Inorganic Molecular Species into Nanocomposite Biphase Arrays

1994

Bio-inspired Resorbable Calcium Phosphate-Polymer Nanocomposites for Bone Healing Devices with Controlled Drug Release

2011

In orthopedic research, increasing attention is being paid to bioresorbable composite materials as an attractive alternative to permanent metal bone healing devices. Typical composites consist of a biodegradable polyester matrix loaded with bioactive calcium phosphate ceramic particles (tricalcium phosphate, TCP or hydroxyapatite, HA) added to improve the biological response and mechanical properties of the neat polymer. The mechanical behavior of such particle-reinforced composites, however, falls far short of the expected performance in high-load bearing situations. Replicating some features of nacre—a strong and tough natural nanocomposite with a very high content of brittle inorganic ph…

Effect of traditional, microwave and industrial cooking on inositol phosphate content in beans, chickpeas and lentils

2003

An high-performance liquid chromatography method for determining inositol phosphate fractions was adapted to legumes. The validity of the method was assessed by estimating the following analytical parameters: linearity (linear response between 125 and 5000 microg inositol hexaphosphate (IP(6))/ml); instrumental precision and method precision (relative standard deviation, %) were 1.9% (IP(6)) for instrumental, and 2.5% (IP(6)) and 8.2% (IP(5)) for method precision. An accuracy was estimated by percentage recovery (72 +/- 3%). The application of this method to raw, conventional, microwave-cooked and ready-to-eat beans, chickpeas and lentils gave IP(6) contents ranging from 0.63 g/100 g dry ma…

Use of two-dimensional thin-layer chromatography for the components study of poly(adenosine diphosphate ribose)

1990

Two-dimensional thin-layer chromatography on cellulose plates has been used for separating and quantifying the three adenosine derivatives: AMP, phosphoribosyl AMP (PRAMP), and (PR)2AMP obtained by venom phosphodiesterase digestion of poly(ADP-ribose). In vitro synthesized polymer, up to 300 derivatives in length were studied. Some parameters of the complexity of poly(ADP-ribose) could be deduced from our results: (i) The first branching point appears in fragments of approximately 21 derivatives in length. (ii) The branching points are located at regular distances of approximately 41 derivatives from each other.

Poly(U) RNA-templated synthesis of AppA.

2015

Simple nucleotide templating activities are of interest as potential primordial reactions. Here we describe the acceleration of 5′-5′ AppA synthesis by 3′-5′ poly(U) under normal solution conditions. This reaction is apparently templated via complementary U:A base-pairing, despite the involvement of two different RNA backbones, because poly(U), unlike other polymers, significantly stimulates AppA synthesis. These interactions occur in moderate (K+) and (Mg2+) and are temperature sensitive, being more efficient at 10°C than at 4°C, but absent at 20°C. The reaction is only slightly pH sensitive, despite potentially relevant substrate pKa’s. Kinetic data explicitly support production of AppA b…

Spectroscopic and structural characterization of pure and FeCl3-containing tri-n-butyl phosphate

2014

The spectroscopic properties and liquid structure of pure tri-n-butyl phosphate (TBP) and FeCl3/TBP solutions have been investigated by Uv–Vis and Raman spectroscopies, X-ray diffraction and conductometry. Uv–Vis and Raman spectra, supported by conductometric measurements, consistently indicate that the solubilized salt is present mostly as TBP n [FeCl3 − n ] n+ and FeCl4 − complex ions due to specific interaction with the TBP phosphate group. Thanks to this interaction, a high amount of salt (up to 13 % w/w) can be dissolved despite the relatively low dielectric constant of TBP. The X-ray diffractogram of pure TBP has been interpreted in terms of three main contributions which can be attri…

Immobilization of enzymes by multilayer microcapsules

1994

A method is described to obtain a new type of microcapsules for immobilization of enzymes or living cells. The wall of these capsules consists of several layers of poly(ethyleneimine) and poly(acrylic acid). The idea is that diverging properties of the whole assembly can be better controlled when the membrane is built up by several consecutive steps, each being optimized with respect to a special property, for example, permeability or mechanical strength. The encapsulation of acidic phosphatase and the cleavage of p-nitrophenyl phosphate was used as a model system. The charged capsules were characterized by their enzymatic activity, as a function of membrane composition (number and sequence…

Poly(phosphonate)-mediated Horner–Wadsworth–Emmons reactions

2015

A novel, general protocol for a polymer-mediated Horner–Wadsworth–Emmons (HWE) reaction is reported. The polyvalent polymeric reagent was prepared via acyclic diene metathesis (ADMET) polymerization. Homo- and copolymers of reactive poly(phosphonate)s with molecular weights up to 40 000 g·mol−1 and molecular weight dispersities Đ < 2 were successfully synthesized. Subsequent application of these polymers in the HWE reaction to prepare a library of aromatic α,β-unsaturated ketones (chalcons) has proven to be an efficient synthetic pathway to minimize purification efforts, as the polymeric side-product can be removed by simple precipitation. In this paper we also demonstrate for the first tim…