Analysis of sulfur in soil and plant digests using methane as a reaction gas for ICP-MS.

Quantitation of sulfur (S) is vitally important for analysis of agricultural soil and plant samples due to the requirement of S in living organisms. Although inductively coupled plasma mass spectrometry (ICP-MS) is a commonly used and robust instrument for multi-elemental detection, S is usually analysed by ICP-optical emission spectroscopy (OES) since S quantitation poses a particular challenge for ICP-MS due to interferences on all S isotopes. The requirement for analysis by two instruments increases time and cost for sample analysis, hence analysis by one instrument is desirable.

Investigation of the Potential of Repurposing Medium-Density Fiberboard Waste as an Adsorbent for Heavy Metal Ion Removal.

Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions.

A Porous Fluoride-Substituted Bovine-Derived Hydroxyapatite Scaffold Constructed for Applications in Bone Tissue Regeneration.

Hydroxyapatite is widely used in bone implantation because of its similar mineral composition to natural bone, allowing it to serve as a biocompatible osteoconductive support. A bovine-derived hydroxyapatite (BHA) scaffold was developed through an array of defatting and deproteinization procedures. The BHA scaffold was substituted with fluoride ions using a modified sol-gel method to produce a bovine-derived fluorapatite (BFA) scaffold.

Chitosan: A review of molecular structure, bioactivities and interactions with the human body and micro-organisms.

Chitosan has many desirable attributes e.g. antimicrobial properties and promoting wound healing, and is used in various applications.

Chitosan: A review of sources and preparation methods.

Chitosan, derived from chitin, has many desirable biomedical attributes. This review aims to explore different sources of chitin and methods of chitosan production with industrial consideration. This article first discussed different sources of chitin for industrial scale production, with considerations given to both their environmental impacts and commercialization potential.

Study of biomorphic calcium deficient hydroxyapatite fibres derived from a natural() leaf fibre template.

The complex structure of natural bio-organic matter has inspired scientists to utilise these as templates to design 'biomorphic materials', which retain the intricate architecture of the materials while acting as a useful bioactive material. Biomorphic hydroxyapatite-based fibres were synthesised usingleaf fibre as a template, which constitutes a powerful method for manufacturing bioactive ceramic fibres. Furthermore, in creating the hydroxyapatite-based fibres, a natural source of calcium and phosphate ions (from bovine bone) was utilised to create the digest solution in which the leaf fibres were immersed prior to their calcination to form the inorganic fibres.

A Review of The Lesser-Studied Microemulsion-Based Synthesis Methodologies Used for Preparing Nanoparticle Systems of The Noble Metals, Os, Re, Ir and Rh.

This review focuses on the recent advances in the lesser-studied microemulsion synthesis methodologies of the following noble metal colloid systems (i.e., Os, Re, Ir, and Rh) using either a normal or reverse micelle templating system.

Special Issue: Novel Advances and Approaches in Biomedical Materials Based on Calcium Phosphates.

Research on calcium phosphate use in the development and clinical application of biomedical materials is a diverse activity and is genuinely interdisciplinary, with much work leading to innovative solutions for improvement of health outcomes. This Special Issue aimed to summarize current advances in this area. The nine papers published cover a wide spectrum of topical areas, such as (1) remineralisation pastes for decalcified teeth, (2) use of statins to enhance bone formation, (3) how dolomitic marble and seashells can be processed into bioceramic materials, (4) relationships between the roughness of calcium phosphate surfaces and surface charge with the effect on human MRC osteogenic differentiation and maturation being investigated, (5) rheological and mechanical properties of a novel injectable bone substitute, (6) improving strength of bone cements by incorporating reinforcing chemically modified fibres, (7) using adipose stem cells to stimulate osteogenesis, osteoinduction, and angiogenesis on calcium phosphates, (8) using glow discharge treatments to remove surface contaminants from biomedical materials to enhance cell attachment and improve bone generation, and (9) a review on how classically brittle hydroxyapatite based scaffolds can be improved by making fibre-hydroxyapatite composites, with detailed analysis of ceramic crack propagation mechanisms and its prevention via fibre incorporation in the hydroxyapatite.

A Review on the Use of Hydroxyapatite-Carbonaceous Structure Composites in Bone Replacement Materials for Strengthening Purposes.

Biomedical materials constitute a vast scientific research field, which is devoted to producing medical devices which aid in enhancing human life. In this field, there is an enormous demand for long-lasting implants and bone substitutes that avoid rejection issues whilst providing favourable bioactivity, osteoconductivity and robust mechanical properties. Hydroxyapatite (HAp)-based biomaterials possess a close chemical resemblance to the mineral phase of bone, which give rise to their excellent biocompatibility, so allowing for them to serve the purpose of a bone-substituting and osteoconductive scaffold.

Substituted hydroxyapatites for bone regeneration: A review of current trends.

At present hydroxyapatite (HA) is been extensively investigated for biomedical applications, largely as a result of its similarity in composition to the mineral portion of bone. Although HA undergoes osseointegration and is bioactive and osteoconductive, the inherent brittleness and low fracture toughness limits its use under load bearing conditions, also once implanted in the body, HA takes a long time to resorb. The crystal structure of HA is conducive to a variety of ionic substitutions.

Development and characterization of a xenograft material from New Zealand sourced bovine cancellous bone.

A xenograft (bovine hydroxyapatite [BHA]) was developed from New Zealand sourced bovine cancellous bone by a successful defatting and deproteinizing procedure. The BHA was chemically, compositionally and structurally characterized. Fourier transform infrared spectroscopy confirmed the removal of organic matter from the bone matrix and the presence of carbonate ( CO32-), hydroxyl (OH ), and phosphate ( PO43-) functional groups.

Vacuum-assisted infiltration of chitosan or polycaprolactone as a structural reinforcement for sintered cancellous bovine bone graft.

Sintered cancellous bovine bone (SCBB) offers numerous advantages as a bone graft substitute material; however, its mechanical properties require improvement. In this study, SCBB was infiltrated with ε-polycaprolactone (PCL) or chitosan/monetite to improve mechanical properties while retaining valuable SCBB structure. Organic infiltrating solutions consisted of (i) chitosan and monetite (CaHPO(4)) dissolved in hydrochloric acid; (ii) chitosan, monetite (CaHPO(4)), and genipin dissolved in hydrochloric acid; or (iii) PCL polymer dissolved in tetrahydrofuran (THF).

Synthesis and characterization of polymer-protected rhodium and palladium sols in mixed media.

A series of polymer-protected rhodium and palladium sols were generated in mixed (organic/aqueous) dispersion media. Protecting polymers used were PAA, PVP, PVA and an oligosaccharide-based protecting agent, arabinogalactan. This is the first systematic study of colloids generated in mixed solvent dispersion media with these protecting agents.

The application of co-melt-extruded poly(ε-caprolactone) as a controlled release drug delivery device when combined with novel bioactive drug candidates: Membrane permeation and Hanson dissolution studies.

Eight bioactive drug compounds (abamectin, amoxicillin, dexamethasone, dexamethasone valerate, ketoprofen, melatonin, oestradiol 17β, and oestradiol benzoate) were combined via melt extrusion and disc pressing processes with a polycaprolactone (PCL) matrix and were then evaluated and compared via membrane diffusion and Hanson dissolution studies. This investigation was to determine the potential of this matrix to act as a controlled release drug delivery vehicle for a number of drugs not previously combined with PCL in a melt extrusion mix. The inclusion of the progesterone/PCL system, for which the drug release behaviour has been well studied before was intended for comparison with the PCL systems incorporating drugs that have received little research attention in the past.

Phosphorylated, cellulose-based substrates as potential adsorbents for bone morphogenetic proteins in biomedical applications: a protein adsorption screening study using cytochrome C as a bone morphogenetic protein mimic.

Screening studies aimed at identifying useful biomedical materials that (when combined with implants) can attract bone morphogenetic proteins to their surfaces have been conducted. In this paper, the screening process has involved carrying out protein adsorption studies using cytochrome C, as a BMP protein mimic on phosphorylated cellulose-based substrates. These studies have shown that phosphorylation of cellulose produces materials that are capable of attracting the adsorption of cytochrome C to their surface.

In situ characterisation of the aqueous gold colloid interface using CO as a surface probe: IR spectroscopic studies.

Fourier transform infrared (FTIR) spectra are presented of CO gas-treated protected gold colloids prepared from hydrazinium hydrate reduction of an Au(III) precursor which reproducibly feature a weak, shortlived peak at ca. 2169 cm(-1). When the gold colloid was treated with 99% isotopically enriched (13)CO gas, the IR peak shifted to a frequency of 2114 cm(-1) which indicated that it represented a simple gold monocarbonyl species.

Growth of calcium hydroxyapatite (Ca-HAp) on cholesterol and cholestanol crystals from a simulated body fluid: A possible insight into the pathological calcifications associated with atherosclerosis.

An experimental study into calcium phosphate (CP) nucleation and growth on cholesterol and cholestanol surfaces from a supersaturated simulated body fluid (SBF) is presented with the overall aim of gaining some fundamental insights into the pathological calcifications associated with atherosclerosis. Soaking of pressed cholesterol disks at physiological temperature in SBF solutions was found to lead to CP nucleation and growth if the disks were surface roughened and if an SBF with concentrations of the calcium and hydrogen phosphate ions at 2.25x physiological concentrations was used.

The evaluation of processed cancellous bovine bone as a bone graft substitute.

Objective: To determine the ability of a novel bovine cancellous bone xenoimplant to act as an osteoconductive graft in an ovine femoral defect model. An autograft harvested from the xenoimplant site was placed in a contralateral limb defect for comparison.

Material And Methods: The xenoimplant used had been rendered immunologically inert by a novel defatting and deproteinating process.

In situ infrared spectroelectrochemical studies of the corrosion of a nickel electrode as a function of applied potential in cyanate, thiocyanate, and selenocyanate solutions.

This paper presents the first subtractively normalized interfacial Fourier transform infrared spectroscopic (SNIFTIRS) study of the corrosion system Ni/XCN(-) (X=O, S, Se), pH 11, [XCN(-)]=0.05 molL(-1), supporting electrolyte 0.1 molL(-1) KNO(3), for a nickel electrode as a function of applied potential.

Rhenium-Based Hydrosols: Preparation and Properties.

Transmission electron microscope (TEM), ultraviolet-visible (UV/vis), electrospray mass spectrometric (ESMS), and X-ray photoelectron spectroscopic (XPS) studies are presented on a little studied rhenium hydrosol system produced by reduction of aqueous K(2)ReCl(6) with hydrazine in the presence or absence of a gum arabic protecting agent. The studies indicate that hydrazine-generated "rhenium hydrosols" are unstable in water and slowly dissolve over time in aqueous media to form the highly stable perrhenate ion. Copyright 2001 Academic Press.