No description available.

No description available.

No description available.

A range of ion selective electrodes (ISEs) for the determination of nitrate has been produced using polymeric membranes containing immobilised quaternary ammonium salts as the ion exchanger. The use of the conventional solvent casting technique gave rise to a relatively low cross-link density, two sided response and poor thickness control. The development of a hot pressing technique resolved all the se problems and would readily suit large scale manufacturing. In this work poly(acrylonitrilebutadiene)(NBr) was selected as the membrane matrix and was robust, gave enhanced selectivity coefficients and extended membrane lifetime. The best electrode fabricated contained 6-5% m/m triallyloctylammonium bromide, 7-2% m/m dicumyl peroxide and 39-7% m/m2 -nitrophenyloctyl ether in a 50% ACN content N Br polymer matrix. The electrode had a lifetime in excess of 665 days and the response to nitrate was Nernstian in the range I x 10" to I x 10' mol dm-1 of nitrate. The limit of detection was 4-5 x IW mol dm-1 and the selectivity coefficient k Pot NO,,- - C1 was 5.3 xIW. The immobilised ion exchanger membrane electrode offered superior lifetime and mechanical strength. The cross-link density of the membranes was determined by solvent swelling and the use of the Flory-Rehner equation. The role of cross-link density upon the electroanalytical properties of membranes was investigated in the range 0-6 x 10' to 11-0 x 10' mol cross-link cm-'. The membranes were studied using electron microscopy and the conditioning process monitored using ion exchange chromatography. Two different response mechanisms were proposed dependent on the membrane composition and the inclusion of solvent mediator.

Jagals, P., Prof. du Preez, H.H., Prof.

Water quality evaluation is a global concern due to its effect on public health. Different procedures can be implemented to evaluate specific standards of water quality. DNA extraction to characterize the microbial community in the water distribution systems is important. To optimize the DNA extraction process the effect of residual chlorine and water composition was tested. The results exposed the limited effect of the samples dechlorination. Total cell number effect can be varied according to water quality. Also, the study indicated the possible inhibitory effect of the rust on the DNA extraction from drinking water samples.

Thesis (MSc (Psychology))--University of Limpopo, 2011. / South Africa has a long history of alcohol use. Traditionally alcohol was used on specific occasions, and, only after the introduction of commercial alcohol, was it used by the youth, women and males on a more regular social basis. Colonialism and separate development discriminated against Blacks, who were disenfranchised and they were also not allowed to buy, use or sell alcohol freely under specific laws. After South Africa became a democratic country in 1994 all such regulation was taken out of the statute books and all South Africans over the age of eighteen could buy, sell or use alcohol subject to certain conditions. The breweries expanded their markets and advertising campaigns were introduced to target the previously disenfranchised groups. As a result of this South Africans, particularly students’ are rated high in terms of alcohol consumption. Health and social problems related to alcohol escalated as well. The research design for the study is a randomised non-experimental survey design. The study uses both qualitative and quantitative techniques to analyse the data which is consistent with a mixed method approach. Descriptive statistics and the chi-square are used to analyse the majority of the data while Thematic Content analysis is used analyse qualitative data. The results underpinprevious research in that students have the tendency to use and abuse alcohol with negative academic and social consequences. It was found that both males and femaleshave similar drinking patterns in terms of when they drink, how much they drink and what type of alcohol they drink. Students of both sexes were generally found to have poor knowledge about alcohol. Qualitative results suggest that some students are aware that moderate alcoholconsumption is socially acceptable and responsible behaviour. However, they are also aware that there is a problem with alcohol use and abuse amongst their peers.

Thesis (MPH)-- University of Limpopo (Medunsa Campus), 2012. / Alcohol use and abuse is highly prevalent among university students and it is a major health concern for universities across the globe. It is important to identify students at risk of, and those who engage in heavy drinking and the reasons thereof so that early identification and referral for intervention can be made before students at risk suffer dire consequences. The aim .of this study was to determine the pattern of alcohol use among the health care science students at the University of Limpopo (Medunsa campus). A quantitative, cross-sectional approach was utilised. Data was gathered by the use of a self administered questionnaire. Stratified and cluster techniques were used to obtain the sample. Descriptive statistics was used to describe data and explore relationships. Relationships between variables of interest were established by using the Spearman's rank correlation coefficient (rho). The prevalence of alcohol use among the participants was relatively low (23%). 15% of respondents were categorized as light drinkers, 3.5% moderate drinkers and 3.5% heavy drinkers. The respondents scored the lowest on the Peer Pressure motive for alcohol use (35.6%) and equal on the Personal Enjoyment and Tension Reduction category, both having mean scores of39% respectively. The Spearman's rho revealed statistically significant relationships among the different types of drinking categories and the following drinking motives: to experience a good time, to feel good, to cheer up and to ease when blamed. This studies finding revealed that the prevalence of alcohol use among health care science students at the University of Limpopo (Medunsa campus) was exceptionally low. The study also brought to light that social motives for drinking was the primary drinking motive and the correlations between the patterns and motives for drinking were only found among four sub categories from the drinkin motives sub-scales.

acase@tulane.edu / Alcohol and drug use to cope is a common phenomenon that is found in those who are of college age. Drinking and drug use to cope has negative short- and long-term outcomes including chronic disease and possibly death. Alcohol and drug use to cope may be more common when individuals are not able allocate other resources in order to cope with their strong uncomfortable feelings (specifically depression, anger, and anxiety) and stress. Women and people of color may be particularly vulnerable to these patterns of maladaptive coping. I hypothesize that increased negative affect, stress, and avoidant coping will be associated with more alcohol and drug use. I also predict that there will be increased alcohol and drug use behavior for women and people of color in the context of negative affect, stress, and avoidant coping. The AUDIT, Brief COPE, DASS, PROMIS Anger, PSS, Race-Related Stress Item, and AAQ-II were used in data collected cross-sectionally from 360 participants. Pearson’s correlations and multiple regressions were used to analyze the data. Men and women did not differ in their alcohol and drug use, though people of color did consume less alcohol then their white counterparts. Alcohol and drug use was highly correlated with negative affect and general stress. It also was found that men displayed more substance use behavior when faced with race-stress/perceived discrimination. Predicted relationships between race-related stress and alcohol and drug use and between avoidant coping and alcohol and drug use were not supported. In addition, none of the other hypothesized interactions were statistically significant predictors of alcohol and drug use. Implications for supporting college aged individuals are discussed. / 1 / Chinwendu Duru

This dissertation presents three separate studies designed to provide structure and evidence-based insight into the characteristics associated with responsible drinking. First, a primer on the responsible drinking message will be presented discussing: (a) the origins and evolution of this message, (b) alcohol product advertisements evincing a responsible drinking prevention message, and (c) practical and ethical concerns associated with brewer-sponsored responsible drinking campaigns. Additionally, the primer will also present systematic reviews of twenty (n=20) empirical studies utilizing the responsible drinking concept to determine the manner in which researchers currently conceptualize and explain characteristics of responsible drinking in their reports. Secondly, a qualitative examination of college students’ beliefs, motivations, intentions, and behaviors regarding responsible drinking will be presented. Employing an emergent design, the data collection process encompassed four focus group sessions and three separate, personal interviews. The final sample size comprised thirteen individuals (Focus Group n=10; Personal Interview n=3). A conceptual model will also be proposed to assist in interpreting the qualitative findings and theorizing about factors influencing intentions to drink responsibly. Lastly, drawing upon the theoretical model and qualitative findings, the development and rigorous psychometric testing of a web-based instrument - Characteristics of Responsible Drinking Survey (CHORDS) – will be discussed. Zoomerang™ served as the host-site for both the pilot- and final testing phases of the CHORDS. The final sample (n=729) comprised a random set of individuals drawn from all currently enrolled students (undergraduate and graduate) attending Texas A&M University (TAMU) in College Station. Principal components exploratory factor analysis revealed the CHORDS consists of five scales (61 total items) whose scores exhibit high internal consistency reliability. These scales include: Behavioral Beliefs, Motivation, Self-Efficacy, Barriers and Behavioral Intention. Scales were found to measure the same underlying construct, as outlined in the theoretical model. Prior to this study, scientific literature contained no scholarly attempts to distinguish responsible drinking characteristics; no theoretically-based explanation or examination of the interactions among responsible drinking variables; and no instruments expressly intended to measure responsible drinking intentions. Thus, this study represents the first step toward addressing the limitations associated with responsible drinking and filling the apparent conceptual gaps.