Dispersive X-ray Elemental Analysis Research Articles

Inability of energy dispersive X-ray analysis to identify particulate polyethylene.

There are limitations to all techniques used to identify particulate polyethylene in histological specimens. The goal of our study was to determine if remnant metal elements used during the catalytic production of ultra high molecular weight polyethylene, could be used as markers for particulate polyethylene detection in histological specimens. It was hypothesized that these catalyst elements could be detected in polyethylene using energy dispersive X-ray elemental analysis. Six samples from five different companies were evaluated. These included virgin polymer powder, polyethylene bar stock, and artificial joint components. Five specimens from each of the six samples were analyzed with energy dispersive X-ray elemental analysis. After elemental analysis was completed, only 2 of 30 specimens were positive for the catalyst elements. In the remaining 28 specimens, catalyst elements were not detected. Our investigation demonstrates that energy dispersive X-ray elemental analysis is not currently a feasible method of particulate polyethylene detection. Additional techniques will need to be developed to accurately identify particulate polyethylene in histological specimens.

Preparation of hollow-fibre composite carbon-zeolite membranes

Carbon membranes, produced by thermo-oxidative stabilization of polyacrylonitrile (PAN) precursors, were used as porous supports for continuous zeolite layers to give composite zeolite-carbon membranes. Different zeolite growth techniques were used, and the membranes were characterized by means of scanning electron microscopy (SEM), elemental dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD).

Chelate membrane from poly(vinyl alcohol)/ poly( N-salicylidene allyl amine) blend. I: Synthesis and characterization of Co(II) chelate membrane

A Co(II) chelate membrane from a poly(vinyl alcohol)/poly(allyl amine) blend was synthesized. As an intermediate step the blend membrane was modified to a Schiff-base type. Structures of blend and Schiff-base membrane were confirmed by the FT i.r. subtraction method. Differential scanning calorimetry thermograms of blend and Schiff-base membranes showed that the glass transition temperature ( T g) ranges between 40 and 50°C. Co(II) content in chelate membrane was determined by electron dispersive X-ray spectroscopy, elemental analysis and thermogravimetric analysis and ranged between 9.82 and 15.75 wt%. As the membrane becomes chelate with Co(II), the density increases as measured by a density gradient column.

High-performance liquid chromatography on polypyrrole-modified silica

Bare silica and C 18-bonded silica were modified with polypyrrole chloride and polypyrrole chloride-dodecyl sulfate. The packing materials were characterised using scanning electron microscopy, energy dispersive X-ray analysis, elemental analysis and surface area analysis. Both reversed-phase and anion-exchange chromatographic behaviour were determined using a selection of test compounds.

Conjunctival Synthetic Fiver Granuloma: A Lesion that Resembles Conjunctivitis Nodosa

Histopathologic examination of forniceal conjunctival lesions excised from five young patients revealed granulomatous inflammation surrounding filamentous foreign material. Polarization microscopy, special histochemical stains, scanning electron microscopy and energy dispersive x-ray elemental analysis identified the inciting material as predominantly synthetic fabric fiber. Three of these cases initially were diagnosed as conjunctivitis nodosa, an inflammatory reaction to caterpillar setae. Many synthetic fibers contained numerous granules of titanium, barium, or zinc delustering agent, which served to differentiate them from natural fibers or caterpillar hairs. Synthetic fabric fiber is a previously unrecognized cause of conjunctival inflammatory mass lesions

Electron‐optical microscopic study of incipient dental microdamage from experimental seed and bone crushing

No living analogue exists for the hypothetical early hominid hard/tough-seed, coarse-root-eating, and bone-crushing masticatory adaptation. To investigate possible microdamage/microwear to dental enamel caused by such usage, puncture-crushing experiments were carried out on single human teeth, using an Instron compression apparatus on the following six test materials: Makapansgat Limeworks chert (e.g., taphonomy), fresh steer longbone, mongongo nuts, Grewia berries, Carob beans, and wild-onion bulbs. Pairs of extracted unworn third molars were utilized, with one tooth acting as the control. The teeth were mounted, ultrasonically cleaned, and two-stage replicas made with a vinyl polysiloxane elastomer and araldite epoxy resin. After Instron loading and materials failure (1.2-395.0 kg) the test items and the crowns were prepared for comparison with scanning electron microscopy and dispersive x-ray elemental analysis and mapping. The results revealed that although grit adhering to food item surfaces caused microscratches (0.1-1.0 micron wide) similar in appearance to those caused by opal phytoliths in grasses, the dicotyledonous seed coats per se were unable to score enamel. This suggests microscratch morphology alone may not provide a reliable indication of food type. In some cases puncture-crushing of bone and hard legumes produced a localized microfracture pattern (crazing with cracks less than or equal to 0.1-1.0 micron wide) that was readily distinguishable from the simulated taphonomic damage caused by chert fragments, suggesting only analysis of enamel mistaphonomic damage caused by chart fragments, suggesting analysis of enamel microfracture patterns may provide clues as to early hominid dietary adaptations.

Electron Microscopy: A Method for the Diagnosis of Inherited Metabolic Storage Diseases: Electron Microscopy in Diagnosis

In the diagnosis of inherited metabolic diseases, electron microscopy has become an important method complementary to clinical, histological and biochemical assays. The characteristic ultrastructure of stored material as well as the site of accumulation in the cell are shown in a number of metabolic disorders. The most prominent advantages of electron microscopical techniques as compared to alternative techniques are discussed. One of the advantages is the fact that ultrastructural investigation requires only tissue samples of very small size, and another that its results may be obtained within two days. Moreover, transmission electron microscopy permits new and promising analytical methods such as quantitative estimation of organellar changes (morphometry) and energy dispersive X-ray elemental analysis (EDX).

Energy dispersive X-ray elemental analysis of isolated epiphyseal growth plate chondrocyte fragments.

Isolated cells of matrix fragments of freeze fractured and freeze dried growth plate from the four species was analyzed by EDX. Cells were removed from the tissue by stereoscopic microdissection using an SEM and mounted on thin film supports on TEM grids: this approach eliminated specimen X-ray background and reduced instrumental and support background levels to insignificant proportions. Chondrocyte and matrix fragments were dissected and analyzed. Cell Ca reaches EDX detectable levels in hypertrophic cells close to the mineralization front. At all stages of maturation, the cells exhibit high P; however, matrix Ca levels are elevated before P. This data suggests that the early cartilage matrix is accumulating Ca and that the cells' role in this process may be to elevate the matrix Ca and P concentration. All cells showed clear S peaks although these are reduced in late hypertrophic cells. With mineralization, matrix S levels fall, indicating a loss of sulfated proteoglycans. Matrix before mineralization contains more K than would be expected from data of previous studies. It is suggested that while this K may be bound to fixed anionic sites in the matrix, reported values for cartilage lymph and extracellular fluid should be reviewed.