McCrone Associates Inc.

Westmont, IL, United States

McCrone Associates Inc.

Westmont, IL, United States
SEARCH FILTERS
Time filter
Source Type

Karlinsey R.L.,Indiana Nanotech, Llc | Mackey A.C.,Indiana Nanotech, Llc | Dodge L.E.,Indiana Nanotech, Llc | Schwandt C.S.,McCrone Associates Inc.
Journal of Dentistry for Children | Year: 2014

Purpose: Fluoride varnishes are appealing topical fluoride preparations that may provide anticaries benefits. The purpose of this in vitro study was to assess the noncontact remineralization effects of a commercial 5% sodium fluoride varnish on white spot lesions (WSLs). Methods: Three-millimeter diameter enamel cores were extracted from bovine teeth, mounted in acrylic rods, ground and polished, and initially demineralized to create WSLs. Specimens were evaluated for surface microhardness and divided (n=6) into two groups (water control or noncontact 5% sodium fluoride white varnish with tricalcium phosphate, where one 0.50 ml unit dose was applied to acrylic rods instead of directly on WSLs). Groups were cycled in a three-day regimen consisting of two rounds of one-hour treatments and one-hour static immersions in demineralization solution. Between these events, WSLs were immersed in artificial saliva. Remineralization was evaluated using surface and cross-sectional microhardness and high-resolution scanning electron microscopy (SEM). Results: The noncontact varnish treatment produced significantly greater percent surface microhardness recoveries (P<.05) and smaller subsurface lesions compared to the control group (P<.05). SEM revealed comparatively greater WSL porosity reduction for noncontact varnish. Conclusions: Noncontact application of a commercial 5% sodium fluoride varnish reduced white spot lesion porosity and produced significant acid-resistant white spot lesion remineralization.


Schumacher E.F.,McCrone Associates Inc.
Advanced Materials and Processes | Year: 2010

Transmission electron microscopy (TEM) is an ideal technique for analyzing metals and other materials to gain an understanding of their structural and elemental properties on the sub-micrometer to atomic scale. The JEOL JEM-3010 transmission electron microscope at McCrone Associates is configured for materials analysis. Additionally, an energy dispersive X-ray spectrometry (EDS) system attached to the microscope provides elemental identification of features or areas as small as three nanometers. Boston Scientific approached McCrone Associates for a pre-clinical analysis of a novel metal alloy, a modified 316L stainless steel for a vascular stent. It had been modified by addition of platinum to increase radiographic density. TEM imaging provided information about precipitate size, and EDS analysis showed them to contain only chromium and oxygen. TEM imaging showed no evidence of formation of inclusions or precipitates in the metal, and also indicated that the crystalline grains comprising the platinum-enhanced alloy were larger than those in the standard 316L stainless steel.


Niemeyer W.D.,McCrone Associates Inc.
Advanced Materials and Processes | Year: 2012

Identification and characterization of paint deficiencies and foreign contamination causing paint adhesion failures requires specialized analytical microscopy techniques. Adhesion failure of paint on automobiles can take several forms, such as flaking, peeling, and blistering, and can occur at the polymer interface or between paint layers. Once the cause of adhesion failure is determined, appropriate corrective actions can be implemented. Standard light microscopes are used to initially examine an adhesion failure. A polarized light microscope (PLM) equipped with polarizing filters for both transmitted and reflected light illumination provides some contrast enhancement and enables observation of crystalline materials. Fourier transform infrared (FTIR) microscopy is used to analyze, characterize, and identify organic materials isolated from the paint or substrate interface surfaces. A scanning electron microscope with an energy dispersive x-ray spectrometry accessory (SEM/EDS) provides elemental composition of materials and is typically used to identify inorganic materials.


Niemeyer W.D.,McCrone Associates Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

For forensic investigation in the food industry, scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectrometry (EDS) is a powerful, often non-destructive, instrumental analysis tool to provide information about: • Identification of inorganic (and some organic) materials found as foreign contaminants in food products returned by consumers or detected during quality control inspections in the production facilities • Identification of wear particles found in production lines • Distribution of materials within a matrix • Corrosion and failure analysis of production equipment The identification of materials by SEM/EDS is accomplished through a combination of morphology by SEM imaging and the elemental composition of the material by EDS. Typically, the EDS analysis provides a qualitative spectrum showing the elements present in the sample. Further analysis can be done to quantify the detected elements in order to further refine the material identification. Metal alloys can often be differentiated even within the same family such as 300 Series stainless steels. Glass types can be identified by the elemental composition where the detected elements are quantified as the oxides of each element. In this way, for example, common window glass is distinguishable from insulation glass used in many ovens. Wear particles or fragments from breakage can find their way into food products. SEM/EDS analysis of the materials is an important resource to utilize when trying to determine the original source. Suspected source materials can then be sampled for comparative analysis. EDS X-ray mapping is another tool that is available to provide information about the distribution of materials within a matrix. For example, the distribution of inorganic ingredients in a dried food helps to provide information about the grind and blend of the materials. © 2015 SPIE.


Schumacher E.F.,McCrone Associates Inc.
American Laboratory | Year: 2013

Formation of glass delamination flakes and secondary products through reaction of injectable pharmaceutical solutions with glass vial packaging leads to product contamination and costly recalls. Characterization of vials and products by a variety of techniques elucidates delamination mechanisms and drives development of packaging materials and processes to reduce the risk of delamination. Early stages of glass delamination are often observed on the vial interior before glass flakes are evident in the liquid. The vials are taped before being broken to maintain the spatial relationship of fragments. The fine dark lines in the image on the left can be interpreted as being either needle-like structures or plate-like structures viewed edge-on.


Swider J.R.,McCrone Associates Inc.
Powder Diffraction | Year: 2010

The increasing use of microanalysis techniques to analyze particles has demanded more rapid phase identification methods for samples in the 10 μm size range. The XRD analysis of such particles is routinely accomplished using a Rigaku combination instrument combined with particle handling methods. Several case studies show the variety of material analysis problems that can be solved with this technique including identification of multiple mineral phases, corrosion components, and paint samples. © 2010 International Centre for Diffraction Data.


Schwandt C.S.,McCrone Associates Inc.
American Laboratory | Year: 2014

Materials in the form of particulate or engineered objects are relatively easy to characterize in terms of their composition, shape, size, and size distribution, provided they are larger than 1 ?m in average dimension. It is often assumed that nanometer-scale materials are just smaller versions of larger-sized materials made with the same precursors and procedures, but the chemical and physical interactions of submicrometer- or nanometer-scale materials are in fact different-offering new materials with novel properties. The very small scale of these new materials makes them very difficult to accurately characterize, and because of their unique properties, it is critical for materials scientists and engineers to conduct confirmatory analysis to verify the properties of their materials. Fortunately, advances in analytical instrumentation, especially field emission scanning electron microscopy (FESEM), permit characterization of submicrometer-sized materials. Several challenges need to be addressed in order to successfully accomplish a comprehensive, high-quality material characterization. These include: calibrating the scalar measurement tools of the FESEM, understanding the limitations of sample handling and preparation relative to other methods, the inability to use automated methods either in terms of image analysis software or other optical size distribution methods, and using crystal structural analysis to strengthen elemental analysis when small analysis volumes preclude standards for fully quantitative analysis.


Sheppard P.R.,University of Arizona | Bierman B.J.,McCrone Associates Inc. | Rhodes K.,McCrone Associates Inc. | Ridenour G.,625 W. Williams | Witten M.L.,Odyssey Research Institute
Journal of Environmental and Public Health | Year: 2012

To improve understanding of possible connections between airborne tungsten and public health, size and geography of airborne tungsten particles collected in Fallon, Nevada, and Sweet Home, Oregon, were compared. Both towns have industrial tungsten facilities, but only Fallon has experienced a cluster of childhood leukemia. Fallon and Sweet Home are similar to one another by their particles of airborne tungsten being generally small in size. Meteorologically, much, if not most, of residential Fallon is downwind of its hard metal facility for at least some fraction of time at the annual scale, whereas little of residential Sweet Home is downwind of its tungsten facility. Geographically, most Fallon residents potentially spend time daily within an environment containing elevated levels of airborne tungsten. In contrast, few Sweet Home residents potentially spend time daily within an airborne environment with elevated levels of airborne tungsten. Although it cannot be concluded from environmental data alone that elevated airborne tungsten causes childhood leukemia, the lack of excessive cancer in Sweet Home cannot logically be used to dismiss the possibility of airborne tungsten as a factor in the cluster of childhood leukemia in Fallon. Detailed modeling of all variables affecting airborne loadings of heavy metals would be needed to legitimately compare human exposures to airborne tungsten in Fallon and Sweet Home. © Copyright 2012 Paul R. Sheppard et al.


PubMed | Washington State Patrol Crime Laboratory and McCrone Associates Inc.
Type: Journal Article | Journal: Forensic science review | Year: 2015

Microscopic trace evidence includes particles from many sources such as biologicals, soil, building materials, metals, explosives, gunshot residues, and cosmetics. The particles are identified by morphological analysis, microscopy, and chemical analysis. Their identity is confirmed by comparison with reference materials or other comparison samples. The probative value of particles of forensic interest depends on their nature and the circumstances of their presence.


Schwandt C.S.,McCrone Associates Inc.
American Laboratory | Year: 2010

Significant developments in visualization technologies and electron optics have led to improvements in secondary electron imaging and characterization of nanometer-scale materials. The latest developments in backscattered electron detectors have produced similar improvements in qualitative compositional imaging. These new detectors produce qualitative compositional maps with nearly the same spatial resolution as secondary electron images, and provide a means of targeting the electron beam for X-ray spectrometer measurements for quantitative analysis. The low-angle backscattered electron (LABE) detector is one such instrument, which is an option on the company's field emission scanning electron microscopes (FESEMs). A material that can be imaged with the LABE detector is a new type ofwound care dressing composed of silver-coated fibers.

Loading McCrone Associates Inc. collaborators
Loading McCrone Associates Inc. collaborators