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J Wheeler

Publications and source records attributed to J Wheeler.

87 records · Page 5Linked to original sources
PubMedDate not supplied

High-temperature electron backscatter diffraction and scanning electron microscopy imaging techniques: in-situ investigations of dynamic processes.

In-situ heating experiments have been conducted at temperatures of approximately 1200 K utilising a new design of scanning electron microscope, the CamScan X500. The X500 has been designed to optimise the potential for electron backscatter diffraction (EBSD) analysis with concomitant in-situ heating experimentation. Features of the new design include an inclined field emission gun (FEG) column, which affords the EBSD geometrical requirement of a high (typically 160 degrees) angle between the incoming electron beam and specimen surface, but avoids complications in heating-stage design and operation by maintaining it in a horizontal orientation. Our studies have found that secondary electron and orientation contrast imaging has been possible for a variety of specimen materials up to a temperature of at least 900 degrees C, without significant degradation of imaging quality. Electron backscatter diffraction patterns have been acquired at temperatures of at least 900 degrees C and are of sufficient quality to allow automated data collection. Automated EBSD maps have been produced at temperatures between 200 degrees C and 700 degrees C in aluminium, brass, nickel, steel, quartz, and calcite, and even at temperatures >890 degrees C in pure titanium. The combination of scanning electron microscope imaging techniques and EBSD analysis with high-temperature in-situ experiments is a powerful tool for the observation of dynamic crystallographic and microstructural processes in metals, semiconductor materials, and ceramics.

Journal Article↗
PubMedDate not supplied

Enzyme-linked immunosorbent assay for anti-streptococcal protoplast membrane antibodies.

An enzyme-linked immunosorbent assay is described for the quantitative determination of circulating antibodies to streptococcal protoplast membranes (SPM) in human sera. The assay was used to study the prevalence of antibodies to SPM of M types 6 and 12 Streptococcus pyogenes in sera from 55 patients with recent streptococcal infection, and 30 normal individuals without clinical evidence of streptococcal infection. No correlation was found between levels of anti-SPM antibodies and ASO titres. However, in serial serum samples from one patient with uncomplicated streptococcal sore throat, it was possible to demonstrate that the increase in the level of anti-SPM antibody paralleled the rise in ASO titre. The anti-SPM antibody level and the ASO titre in this patient persisted throughout a six-month period of follow-up.

Adult↗
PubMedDate not supplied

Multifocal angiomyolipoma in a patient with tuberous sclerosis.

Angiomyolipomas are rare lesions that occur most commonly in the kidney, but also can occur in the liver and rarely, in the lymph nodes. Its rare association with tuberous sclerosis has been suggested, but never proved. We report a patient with multiple visceral angiomyolipomas as well as visceral vessel aneurysms and tuberous sclerosis. The association of the three lesions suggests a possible common connective-tissue defect.

Adult↗
PubMedDate not supplied

The efficacy of a prophylactic knee brace to reduce knee injuries in football. A prospective, randomized study at West Point.

The purpose of this prospective, randomized study was to determine the efficacy of a prophylactic knee brace to reduce the frequency and severity of acute knee injuries in football in an athletic environment in which the athletic shoe, playing surface, athlete-exposure, knee injury history, and brace assignment were either statistically or experimentally controlled. The participants in the study were 1396 cadets at the United States Military Academy, West Point, New York, who experienced a total of 21,570 athlete-exposures in the 1986 and 1987 fall intramural tackle football seasons. The use of prophylactic knee braces significantly reduced the frequency of knee injuries, both in the total number of subjects injured and in the total number of medial collateral ligament injuries incurred. However, the reduction in the frequency of knee injuries (total and medial collateral ligament) was dependent on player position. Defensive players who wore prophylactic knee braces had statistically fewer knee injuries than players who served as controls. This was not true of offensive players who served as controls; they had statistically no difference in the number of knee injuries from players who wore prophylactic knee braces. The severity of medical collateral ligament and anterior cruciate ligament knee injuries was not significantly reduced with the use of prophylactic knee braces.

Adult↗
PubMedDate not supplied

How government policy decisions affect seniors' quality of life: findings from a participatory policy study carried out in Toronto, Canada.

Toronto seniors explored how government policy decisions were influencing their health and well-being. In this participatory policy study, emphasis was upon the lay and critical knowledge of highly informed seniors. Focus groups and interviews revealed that all three levels of governments were seen as not listening to seniors' voices. In nine key policy areas identified as influencing seniors' quality of life--hearing seniors' voices, housing, acute illness care, long-term care, income supports, transportation and mobility, promoting healthy lifestyles, access to information, and hearing voices from cultural communities--many concerns were raised. The gap between government rhetoric and government action on seniors' issues merits public health attention.

Aged↗
PubMedDate not supplied

Serologic evidence of infectious bursal disease virus infection in Iowa turkeys.

Two infectious bursal disease viruses (IBDVs)--a cell-culture-adapted chicken strain designated Edgar strain and a recent isolate from turkeys in Missouri--were used to assay sera from 10 Iowa turkey flocks collected between 1 and 16 weeks of age. The two viruses were serologically distinct in cross-neutralization tests. For all flocks, a similar serologic pattern was found consisting of (1) low maternal antibody titers to turkey IBDV and occasionally to Edgar strain IBDV between 1 and 3 weeks of age, (2) a period of very low or no detectable titers between 3 and 7 weeks of age, and (3) sharply rising high titers to turkey IBDV with low titers to Edgar IBDV beginning at 5 to 8 weeks of age. These findings indicate that infection with IBDV of the serotype represented in this study by the turkey isolate is common in Iowa turkey flocks, whereas infection with IBDV represented by Edgar strain is uncommon. Infection occurred between 3 and 7 weeks of age during the late brooding period or after birds had been moved to an intermediate growing facility. All flocks developed complicated respiratory disease with excessive mortality caused by Escherichia coli septicemia, typically between 3 and 6 weeks of age. Although there was a temporal relationship between IBDV infection and respiratory disease, the possible role of IBDV in the process is unknown.

Animals↗