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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.
211

The integration of computational and spectroscopic information for hydrogen bonded systems

Price, Jason Mark January 2000 (has links)
The infrared spectra of methanol as dilute solutions in CCU and in the vapour phase have been measured between 2500 and 4000 cm"1 and between 1000 and 1100 cm"1 in order to better understand the nature of the hydrogen bonding equilibria present. The integrated absorption coefficient of the monomeric O-H stretching mode is calculated as (2.157 ± 0.025)xl04 m mol" 1 and the proportion of the components associated with the three principal bands and a fourth weaker band estimated. Seven possible components were considered which were monomer, closed cyclic and open chain dimers, trimers and tetramers. Ab initio calculations were carried out on these components using six basis sets up to the restricted Hartree Fock 6-31 l-H-G(3df,3pd) level. Relevant calculated infrared wavenumber and intensity values, O-H...O bond lengths and hydrogen bonding energies are reported. The cyclic dimer is shown to be a transition state with the open dimer forming a stable minimum energy form. In the case of the trimer and tetramer the hydrogen bonding energy is calculated to be respectively 12 and 32 kJ mol" 1 greater in the cyclic form than in the open form with good agreement at the RHF6-31G(d) and RHF 6-31++G(d,p) levels. The experimental and theoretical results are consistent with an equilibrium involving monomer, open dimer, cyclic trimer and cyclic tetramer. Also, ab initio calculations are reported for HC1 complexes of H^CO, CH3HCO, (CH3)2CO, HCN, CH3CN, C2H5CN, HCOCN and CH3COCN. Comparison with experimentally determined values of hydrogen bond energy, HC1 wavenumber shifts and bond lengths for the four smallest complexes suggest a suitable method and basis set is B3LYP/6-311++G(2d,2p). In the case of CH3HCO there are two possible isomers in which the HC1 is cis and trans to the aldehydic H atom (low and high energy forms respectively). The two bi-functional complexes each have three possible isomers; HC1 may bond to the nitrile group, to the carbonyl group cis to the nitrile or to the carbonyl group trans to the nitrile . Calculated values of hydrogen bond energy; harmonic HC1, CO and CN stretching modes; hydrogen bond lengths and other associated lengths and angles are reported for all seven mono- and all six bi-functional complexes and compared with experimentally determined values, when known. These properties are predicted in other cases including those of the newly described high energy complex of CH3HCO, and those of three newly described complexes of both HCOCN and CH3COCN.
212

Investigating the Unique Effect of Marriage-Related Motives to Limit Drinking on Young Adult Drinking After Marriage

January 2016 (has links)
abstract: The present study aimed to test the effect of role socialization processes on declines in drinking after marriage. Role socialization as it relates to marriage theorizes that after occupying a role, individuals are likely to change their behaviors to conform to role expectations of marriage, such as reductions in drinking (Yamaguchi & Kandel, 1985). Previous literature has examined declines in drinking behaviors after marriage and inferred that role socialization was the underlying process. This study is the first to directly test whether beliefs that alcohol is harmful to the marital role predicted declines in frequency of drunkenness after marriage. Ordered probit regression was used to test the effect of marriage-related motives to limit drinking on declines in frequency of drunkenness from before marriage to after marriage. Analyses revealed that marriage-related motives to limit drinking were not significantly predictive of declines in frequency of drunkenness after marriage. Only partner drinking emerged as a significant predictor of declines in frequency of drunkenness after marriage. These results highlight the need for a reliable and valid measure of role socialization processes as they relate to the marital role. Furthermore, future studies should consider studying participants at different time points after marriage and consider measuring commitment to the marital role as a moderator. Such studies will help to better understand the results of this study as well as better understand the marriage effect on drinking. / Dissertation/Thesis / Masters Thesis Psychology 2016
213

Attempted synthesis of a [beta] or [gamma] resorcinyl alcohol

Ryding, William Wallace January 1952 (has links)
The ultimate objective of this research is the elucidation of the mechanism of the resorcinol-formaldehyde condensation. Whilst a vast literature has been built up about the phenol- formaldehyde condensation, that of resorcinol has received but scant attention, probably because the high reactivity of resorcinol rendered the following of the condensation extremely difficult. The earliest observation concerning the resorcinol-formaldehyde condensation was due to Baeyer who, in 1872, condensed resorcinol with various aldehydes. When the aldehyde was relatively inactive crystalline compounds were obtalned but with acetaldehyde or formaldehyde a resinous product resulted. In 1892 Caro condensed an excess ot resorcinol with formaldehyde in the presence of dilute hydrochloric acid; the product obtained recrystallised from alcohol as white microsoopic crystals, decomposed without melting at 250° and was stated to be bis (2- 4 dihydroxyphenyl) methane ... In decidlng upon the most suitable lines of attack it would seem that a survey of the literature relating to the phenol-formaldehyde concentration which might be expected to be closely related to that of resorcinol, would be of value. Summary of p. 1-5
214

Metabolic interactions between alcohol, the liver and the gastrointestinal tract

Campbell, Stewart January 2002 (has links)
No description available.
215

Impact of Regular Low-Level Alcohol Consumption on Cognitive Interference and Response Inhibition: An fMRI Investigation in Young Adults

Hatchard, Taylor January 2017 (has links)
The purpose of the present dissertation was to shed light on the neurophysiological effect of regular consumption of low amounts of alcohol on two important aspects of executive functions, cognitive interference and response inhibition, using functional magnetic resonance imaging (fMRI) in a sample of young adults. Participants were recruited from the Ottawa Prenatal Prospective Study (OPPS), a longitudinal study that has collected data from participants from infancy to young adulthood, which permitted control of a number of potentially confounding drug and lifestyle variables. This allowed for investigation of the unique effect of alcohol use on executive functions. The dissertation itself is comprised of two original manuscripts: the first study compared low-level alcohol users to controls on performance of the Counting Stroop, a task of cognitive interference; and the second study compared users to controls on performance of the Go/No-Go, a task of response inhibition.Although the results of both studies found no performance differences between groups, low-level alcohol users had significantly more brain activation in several regions, including areas not typically associated with task processing, compared to irregular or non-drinker controls. This difference in neurophysiology may be reflective of compensatory strategies within the brain, whereby the recruitment of additional regions may be attempting to compensate for potential underlying deficits that occur with increasing cognitive demand. While further research is needed to validate this hypothesis, the present findings highlight the vulnerability of the developing brain.
216

Mercury-Sensitized Photochemical Reactions of Isopropyl Alcohol

Brown, Robert Wade 08 1900 (has links)
This thesis discusses the mercury-sensitized photochemical reactions of isopropyl alcohol.
217

Exploratory studies of photocyclization and photosolvolysis of biaryl methanols

Shi, Yijian 26 July 2018 (has links)
The photocyclization and photosolvolysis of a series of hydroxy-substituted biaryl methanols [special characters omitted] have been studied. The proposed mechanism involves deprotonation of the HOAr moiety and heterolytic cleavage of the C-O bond of the hydroxymethyl group [special characters omitted] in the first excited singlet state (S1), to give biaryl quinone methide intermediates, which subsequently cyclize to the corresponding chromene product and/or react with solvent to give the solvolysis product. The formation of these quinone methide intermediates is facilitated by the excited state planarization and the subsequent charge polarization (negative charge transferred from the HOAr ring into the [special characters omitted] ring) of the biaryl. Although both of these processes are influenced by steric and electronic factors, the latter turns out to have a more significant effect on reaction efficiency. When the geometry of the molecule goes from a twisted conformation to a more planar form, the molecule becomes more conjugated and thus gains delocalization energy. This energy is generally larger for the planarization in the S1 state than in the ground state. When it is large enough to overcome the steric repulsion for twisting, biaryls can planarize efficiently in the excited state, which is true for most biphenyl systems. However, it is shown that the deprotonated forms [special characters omitted] of these biaryls have an even larger driving force for S1 planarization than the neutral forms [special characters omitted]. Thus, biaryls with naphthalene ring(s) joined at the 1-position which do not planarize efficiently in the neutral form can still reach a more planar geometry after adiabatic deprotonation of the phenolic hydroxy group in S1. That is, the photocyclization of these molecules proceeds via initial adiabatic deprotonation from the twisted S1 state, followed by twisting (to the planar form) and subsequent charge polarization which expels the hydroxy group at the benzylic position [special characters omitted], to give the required quinone methide intermediate. The o,o'-biaryl quinone methides derived from the o,o'-substituted biaryl methanols are very short-lived due to rapid intramolecular ring closure and are therefore not detectable by nanosecond laser flash photolysis. The o,p’- and p,p'-biphenyl quinone methides, however, do not cyclize and as expected, are readily observable by nanosecond laser flash photolysis. When the benzylic hydroxy group is replaced by other leaving groups, the reaction can be used, in principle, as a photodeprotecting reaction and also to photogenerate acid. These and other results of the Thesis have uncovered many interesting mechanistic details of this new class of reaction and hence have increased our general knowledge of the excited state behavior of aromatic molecules. / Graduate
218

Modelling of batch and fed-batch ethanol fermentation

Glyn, Julian E H January 1989 (has links)
Two series of batch and fed-batch fermentations were carried out using S.cerevisiae in a semi-defined medium containing 200 gl-1 glucose as limiting substrate. Growth rates were calculated and the data used to test the applicability of eight empirical kinetic models. The form proposed by Levenspiel, combining the concept of a limiting ethanol concentration with a power-law form, gave the best results with these data. Glucose concentration was found to have a far smaller, though not negligible, effect on growth rate under these conditions. It was also observed that in fed-batch fermentations the total substrate uptake rate of the broth became constant soon after commencement of feeding, without cessation of growth. It is suggested that ethanol inhibits the synthesis of a rate-controlling enzyme in the glycolyti·c chain, but no previous work could be found to support or refute this explanation. A quasi-mechanistic model of growth under the condition of constant substrate consumption rate is formulated and discussed.
219

Cerebral damage associated with alcoholism

Bolter, John Francis 01 January 1979 (has links)
The neuroanatomical consequences of chronic ethanol ingestion were investigated using neuropsychological tests selectively sensitive to damage in circumscribed brain areas-~~~ The performance of a group of male alcoholics (N=15) with a self-reporte?- drinking history less than ten years, and a group of male alcoholics (N=15) with a self-reported drinking history of ten or more years was compared to a group of male nqnalcoholic controls (N=15). l.A--multiple covariate analysis was done prior to analyzing group differences to determine what influence three covariates (age, education and socioeconomic status) had on the group performances. Results from this analysis indicated that some of the tests were significantly influenced by age or education but no significant Group x Covariate interactions were observed. /JCn agreement with numerous neuropathological findings, the late stage alcoholics were found to be principally deteriorated on the tests of frontal lobe functioning, followed by lesser impairment on the tests of temporal lobe functioning, with no evidence of impairment on the tests of parietal lobe functioning~ No significant group differences were found betv1een the early stage alcoholics and the controls~ Small but negative correlations were found between both the duration of alcoholism and the average amount of alcohol consumed with each of the neuropsychological measures given in this study.
220

Some Pregnant Women Still Don't Believe Drinking Is Dangerous

Bailey, Beth A., Sokol, Robert J. 01 January 2014 (has links)
No description available.

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