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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Effects and management of lactobacilli in yeast-catalyzed ethanol fermentations

Narendranath, Neelakantam Varadarajulu 01 January 2000 (has links)
This thesis focuses on the effects of lactobacilli and their end-products, lactic acid and acetic acid, on 'Saccharomyces cerevisiae' growth and fermentation, and on antimicrobials used to manage such contaminants. To assess the effects of the bacteria, normal gravity (22-24 g/100 ml dissolved solids) wheat mashes inoculated with yeast at ~106 colony forming units (CFU)/ml were deliberately infected (coinoculated) with each of five industrially important strains of lactobacilli at ~10 5, ~106, ~107, ~10 8, and ~109 CFU/ml. Controls with yeast alone or with bacteria alone (~107 CFU/ml) were included. End-products, yeast growth and fermentation rates were monitored. Results indicated that production of lactic acid by lactobacilli and suspected competition of the bacteria with yeast cells for essential growth factors in the fermenting medium were the major reasons for reductions in yeast growth and decreases in final ethanol yield. A chemically defined minimal medium was used to determine the effects of added acetic and lactic acid, and their mode of action on two strains of ' S. cerevisiae'. The effects of these two acids on yeast intracellular pH (pHi), plasma membrane H+-ATPase activity and on the plasma membrane lipid composition were studied. It was found that the specific growth rates ([mu]) of the two yeast strains decreased exponentially (R2 > 0.9) as the concentrations of acetic or lactic acid were increased. Acetic and lactic acids synergistically reduced the specific growth rate of yeast. Acetic acid caused the yeast cell to expend ATP to pump out excess protons that result from the passive diffusion of the acid into the cell at medium pH (pHe) followed by its dissociation within the cell as a result of higher pHi. Lactic acid (0.5 % w/v) caused intracellular acidification (which could lead to arrest in glycolytic flux) as a result of a significant decrease (P = 0.05) in the plasma membrane H +-ATPase activity. Moreover, the plasma membrane fluidity was reduced due to decrease in unsaturated fatty acyl residues. Among the antimicrobials studied, urea hydrogen peroxide (UHP) was superior compared to stabilized chlorine dioxide and nisin, but its bactericidal activity was greatly affected by the presence of particulate matter. When used near 30 mmoles/L (in unclarified mash), in addition to its bactericidal effect, UHP provided near optimum levels of assimilable nitrogen and oxygen that aided in vigorous yeast fermentation. This process was patented.
262

Könsskillnader i motiv för att dricka alkohol- en studie av studenter på en högskola i mellersta Sverige / Gender differences in motivations for drinking alcohol- a study of students at a university in central Sweden

Linderoth, Anna January 2012 (has links)
The purpose of this study is to investigate the motives underlying the consumption of alcohol among college students and if the motives differ between genders. The study is based on the following questions: What are the motives underlying alcohol consumption among students? Do these motives differ between men and women? Is there any connection between the motives for alcohol consumption and consumption? The study is a quantitative, empirical comparison study and the data presented is mainly descriptive. The study group consists of students from a university in central Sweden. After an exclusion of five students a total of 81 students participated in the survey, of which 55 were female and 26 were male. The average age of all who participated in the study was 24 (sd = 4). The students' alcohol consumption and motives for alcohol consumption were investigated using two instruments: The Alcohol Use Disorders Identification Test (AUDIT) and the Modified Drinking Motives Questionnaire-Revised (M DMQ-R). The questions from the two instruments were combined into a single questionnaire which then was used in the study. The questionnaire was accessible through a link on the internet. Students were recruited via advertisement on announcementboards around the school. A link to the survey was also published on the university's group page and on an application's group page on Facebook. The responses from the questionnaires were transferred to the computer programs Microsoft Excel and SPSS where they were analyzed and summarized. The results showed that the most common reason for drinking among both men and women were social motives. Enhancement motives were also more common than the other motives. There were more women than men who reported conformity motives, enhancement motives and coping with depression as a reason for their alcohol consumption. A few more men than women had indicated that they drink to coop with anxiety. There were a positive relationship only between enhancement motives and alcohol consumption, and this relationship was only among women in the study. There were no correlations between the other motives and alcohol consumption
263

Mechanisms of Fetal Alcohol Spectrum Disorders

Wilson, Shannon Elizabeth 2010 August 1900 (has links)
Alcohol consumption during pregnancy can result in fetal alcohol spectrum disorders (FASD), which encompass a range of physical, behavioral, learning, emotional and social disturbances. Many mechanisms for this array of alcohol-derived fetal injuries have been proposed, but none fully accounts for the deficiencies observed. Alcohol is a ubiquitous drug that may affect the brain at any or all stages of development and at multiple sites; regional differences in vulnerability of different brain structures during different periods of exposure have been demonstrated. This study investigates possible mechanisms for the alcohol induced neurodevelopment damage seen as a result of prenatal alcohol exposure, and also includes evaluation of a potential intervention strategy (glutamine). These experiments all utilized the sheep model, which has distinct advantages over the rodent model for third trimester-equivalent studies (a time of increased vulnerability to the effects of alcohol). The fetal hippocampal formation (pyramidal cells in the CA1 and CA2/3 fields and granule cells of the dentate gyrus) and olfactory bulb (mitral cells) have been altered in response to alcohol exposure in rodent model studies. This study examined the effects on the fetal hippocampal formation and olfactory bulb in response to all three trimester-equivalent alcohol exposure in the sheep model, a species in which the third trimester-equivalent occurs in utero (as opposed to post-natal as occurs in the rodent). It is known that both maternal and fetal cortisol levels increase in response to alcohol. The role of cortisol in mediating fetal cerebellar Purkinje cell loss (known to occur with alcohol exposure) was analyzed. Lastly, the availability of circulating amino acids, both maternal and fetal, in response to alcohol are reported. The results of administration of a single acute dose of glutamine to the ewe, concurrent with alcohol, was evaluated for its ability to prevent the amino acid and pH perturbations known to occur in response to alcohol.
264

Effects of gender and estrous cycle on brain and blood ethanol pharmacokinetics in rats /

Robinson, Donita Lynn, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 122-136). Available also in a digital version from Dissertation Abstracts.
265

The effects of alcohol, executive cognitive function, individual differences, and contextual variables on college men's perceptions of unwanted sexual advances /

Martell, Joel F. January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 98-111).
266

Alcohol-induced fragmentary blackouts : associated memory processes and neural correlates

Wetherill, Reagan Rochelle, 1979- 02 December 2010 (has links)
Alcohol-induced blackouts, or periods of anterograde amnesia without loss of consciousness, were a diagnostic indicator in Jellinek’s (1952) theory of alcoholism and have been correlated with alcohol use problems (Campbell & Hodgins, 1993; Goodwin, Crane, & Guze, 1969; Ryback, 1970; Tarter & Schneider, 1976). Other findings suggest that blackouts are a warning sign of problem drinking, but not a predictor of alcohol use disorders (Anthenelli, Klein, Tsuang, Smith, & Schuckit, 1994). Most published research on blackouts focuses on cognitive deficits among older alcohol-dependent adults, yet recent research indicates prevalence rates for blackouts as high as 50% among college students (White, Jamieson-Drake, & Swartzwelder, 2002). In addition, young adults who reported experiencing a blackout were later told that they had vandalized property, driven a car, or engaged in other risky behaviors without remembering (Buelow & Koeppel, 1995). Despite their high prevalence and associated negative consequences, relatively little is known about alcohol-induced blackouts or their neural, social, and behavioral correlates among non-dependent populations. The current research explored individual variation in memory functioning under sober and intoxicated conditions and alcohol’s effects on neural activation during memory processes. / text
267

Building toward an Intervention for Alcohol-Related Aggression: A Cognitive and Behavior Test of the Attention Allocation Model

Gallagher, Kathryn Elise 16 August 2010 (has links)
This study provided the first direct test of the cognitive underpinnings of the attention-allocation model and attempted to replicate and extend past behavioral findings for this model as an explanation for alcohol-related aggression. Men were randomly assigned to a beverage (Alcohol, No-Alcohol Control) and a distraction (Moderate Distraction, No Distraction) condition. All men were provoked by a male confederate and completed a dot probe task and a laboratory aggression task without distraction or while presented with a moderate distraction task. Results indicated that intoxicated men whose attention was distracted displayed significantly lower levels of aggression bias and enacted significantly less physical aggression than intoxicated men whose attention was not distracted. However, aggression bias did not account for the lower levels of alcohol-related aggression in the distraction, relative to the no-distraction, condition. Discussion focused on how these data inform intervention programming for alcohol-related aggression.
268

Self-awareness, self-consciousness and the self-control of drunken comportment

Ross, David Francis. January 1987 (has links)
The influence of a primarily Public form of self-awareness and of Private and Public Self-Consciousness on drunken physical aggression and complex reaction-time were examined. Two forms of the balanced-placebo design were employed. Results indicated that each form of self-focus played a significant role in the determination of various aspects of drunken comportment. Consumption of alcohol did not eliminate self-aware behavior on the measures employed. Public Self-Consciousness acted to increase drunken impairment. A modified form of the balanced-placebo design proved superior to the standard version for use with moderately high doses (1.32 ml/kg) of alcohol on a measure of subjective intoxication. The implications for the literature on self-focus and drunken comportment are discussed.
269

Temporal effects of prenatal ethanol exposure on the hypothalamo-neurohypophyseal system in the rat (Rattus norvegicus)

Lim, Jenny M January 2004 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 92-105). / Also available by subscription via World Wide Web / xv, 105 leaves, bound ill. 29 cm
270

Availability and sales of alcohol : experiences from Canada and the U.S. /

Trolldal, Björn, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Stockholms universitet, 2005. / Härtill 4 uppsatser.

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