The Strain Index was originally designed to analyze mono-task jobs. An experiment using a grip dynamometer was used to simulate six multiple task jobs to study the effect of complex tasks on localized muscle fatigue and to evaluate six different models used to calcula te a Complex Strain Index score. These models included average Strain Index score, unadjusted summation, duration adjusted summation, complex equation, minimum intensity, and peak intensity. Two methods of calculating a continuous Strain Index score were also analyzed. Ratings of perceived exertion, hand and forearm fatigue and discomfort, Difficulty Rating, maximum voluntary contraction (MVC), and percent strength loss were recorded for each of the six treatments. Electromyography (EMG) was also recorded for the 24 subjects (12 males and females) who completed the experiment. The EMG signal was analyzed using root mean square (RMS), initial mean power frequency (IMnPF), and slope of the mean power frequency (MnPF). Each treatment, lasting one hour each, contained a primary exertion (Task 1) of either 10% or 40% MVC for three seconds and a secondary exertion (Task 2) of either 10% or 40% MVC for one or three seconds. Subjective variables linearly increased (R2 > 0.88) over the duration of the treatments and significantly differed between treatments (p < 0.05). Percent strength loss was the only variable with a gender effect (p < 0.05). RMS values did not indicate fatigue and were constant over each treatment, but were highly correlated with percent MVC. A significant difference was not found in IMnPF between pre and post treatment values or between treatments (p > 0.05). A significant difference was found for MnPF slope pre and post treatment, but no treatment effect was found (p > 0.05). The complex equation method of calculating a Strain Index score was the only model of the six evaluated that met all criteria for being an acceptable method of calculating a Complex Strain Index score. The two continuous methods presented for calculating a Strain Index score should not be used for job analysis until further research evaluates their reliability, validity, and critical scores for Hazard Classification.

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Fractions from white and tannin sorghums were processed into extrudates, thick porridges, and breads. The effects of sorghum type and fraction on the in vitro starch availability of the products were evaluated, and the estimated glycemic indexes (EGI) of the products were obtained. Sorghum extrudates were significantly more slowly digested than corn meal extrudates for all preparation methods (whole, cracked and decorticated kernels). Furthermore, tannin extrudates were less digestible than white sorghum extrudates. The soft endosperm nature of the tannin sorghum limited friction formation inside the extruder, reducing starch gelatinization. On the other hand, condensed tannins also interfered with the starch availability for digestion. White sorghum was more 'suitable' for extrusion, giving extrudates with higher starch degradation and expansion than the tannin sorghums. However, tannin sorghums also gave acceptable products offering the benefit of lower EGI values. Sorghum porridges were more slowly digested than a corn flour porridge when using whole and decorticated flours. In addition, tannin sorghum porridges had a lower starch digestibility compared to all the samples. Tannin sorghum flours produced soft porridges with enhanced initial starch digestibility. However, condensed tannins seemed to offset the starch digestion by limiting starch availability. All sorghum porridges had significantly lower EGI values than the corn porridge. Extrudates and porridges had reduced starch digestibilities and EGI values when using whole grains compared to using the decorticated fractions. This was observed in both the white and the tannin sorghum. Therefore, whole-grain products from sorghum have health benefits attributed to whole grain foods and slower digesting starches; for instance, prevention and treatment of diseases such as diabetes, insulin resistance, obesity, cardiovascular disease, and some types of cancer. When 12% of tannin bran was added to a wheat bread formulation, a slower rate of starch digestion was observed compared to a wheat bread. The high concentration of non-starch components of the bran (i.e. dietary fiber, condensed tannins) affected starch digestion. The addition of tannin sorghum bran significantly reduced the EGI value of wheat bread, besides being a natural source of brown color, and an excellent source of antioxidants and dietary fiber.

Two tannin sorghums, (high-tannin, black with tannin), high anthocyanin sorghum (black), and non-tannin sorghum (white) were used to investigate the effects of sorghum phenolic compounds on in vitro starch digestibility, estimated glycemic indices (EGI) and resistant starch contents (RS) of porridges. Sorghum varieties were chosen to have a wide range of total phenols (3-23 mg/g gallic acid) and tannin contents (0-34 mg catechin eq./g). Normal corn starch, enzyme resistant high amylose corn starch, and whole sorghum grains were cooked with the aqueous fraction of sorghum bran extracts obtained with 70% aqueous acetone. Endosperms of soft and hard sorghum varieties were mixed with sorghum brans and cooked into porridges with distilled water. Hi-tannin, black and black with tannin sorghum bran extracts significantly (p<0.05) decreased starch digestibility and estimated glycemic index (EGI) while they increased resistant starch (RS) contents of normal corn starch, enzyme resistant high amylose corn starch, and whole sorghum grain porridges. The highest reduction in starch digestibility of the porridges occurred with hi-tannin sorghum bran extracts, followed by black with tannin and black sorghum bran extracts. Double cooked corn starch porridges, which were cooked with these bran extracts had EGI values of 49-67 and RS contents of 9.1-57.7%. These RS values are higher than foods such as legumes, whole pasta and whole grain cereals which are considered health foods with low EGI (36-71) and high RS contents (2.9-6.8). Only brans of condensed tannin-containing sorghum varieties (tannin, black with tannin sorghums) significantly (p<0.05) decreased starch digestibility, and EGI, and increased RS contents of the endosperm porridges. When tannin sorghum bran extracts were cooked with zein added to corn starch porridges, starch digestibility of the porridges significantly (p<0.05) increased, while RS significantly (p<0.05) decreased because the zein reacted preferentially with the tannins. The cooking trials indicated that sorghums with tannins significantly reduced the activity of digestive enzymes, reduced EGI, and increased RS contents of porridges. Thus, specialty sorghum varieties have a potential to lower EGI and increase RS contents of starchy foods. Their aqueous bran extracts have potential use to reduce risk factors for type II diabetes and obesity.

Thèse d'exercice : Médecine. Médecine générale : Université de Nantes : 2004. / Bibliogr. f. 80-85 [63 réf.].

Thesis (Ph. D.)--University of Michigan, 1938. / Cover title. "Reprinted from the Physical review, vol. 54, no. 12, December 15, 1938."

Thesis (Ph. D.)--University of Michigan, 1936. / Running title: X-ray refractivity of cerussite. "Reprinted from the Physical review, vol. 51, no. 3, February 1, 1937."

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No description available.

Introduction: Body Mass Index (BMI) is a relative measure of whether an individual’s weight is at a healthy level for their height. A higher BMI is associated with an increased risk of cancer and cardiovascular disease (CVD). However, the biologic mechanisms are not well understood. One proposed mechanism is through changes in global DNA methylation levels, particularly global DNA hypomethylation. Global DNA hypomethylation refers to lower levels of DNA methylation across the entire genome and hypermethylation refers to higher levels of DNA methylation across the entire genome. Changes in methylation levels can affect gene expression, genomic stability, and chromosomal structure. The methylation status of repetitive sequences in the DNA, such as LINE-1, is commonly used to represent a surrogate measure of global DNA methylation levels. Objectives: 1. Quantify and describe LINE-1 DNA methylation in leukocytes in a large sample of healthy volunteers. 2. Examine the relationship between BMI and LINE-1 DNA methylation levels. 3. Assess if sex is an effect modifier of the relationship between BMI and LINE-1 DNA methylation levels. Methods: A nested cross-sectional study was composed of 502 healthy volunteers between the ages of 20 and 50. Subjects completed a study questionnaire and provided blood samples for laboratory analyses. For each subject, DNA was isolated, underwent bisulfite conversion, and LINE-1 DNA methylation levels were measured by Polymerase Chain Reaction (PCR) High-Resolution Melting Curve analysis. For the main analysis, a multivariate linear regression model was used to examine the relationship between BMI and LINE-1 DNA methylation levels, while controlling for confounders. Results: LINE-1 DNA methylation was normally distributed with a mean of 84.52% and a standard deviation of 3.19%. BMI (normal, overweight, and obese categories) was not significantly associated with LINE-1 DNA methylation levels in the adjusted linear regression model (p=0.41) and the interaction term between BMI and sex was not significant (p=0.50). Conclusions: LINE-1 DNA methylation was measured with a high degree of reliability in a sample of healthy volunteers. This research provided a description of LINE-1 DNA methylation levels in a large healthy population and showed that BMI was not associated with global DNA methylation. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2012-04-03 17:23:59.843