MIND0/3 Study of the \u27Thermal Rearrangements of Bicyclobutanylidene

It is found that path (i), which is concerted and stereospecific, is favored both thermodynamically and kinetically, in agreement with exp~\u27rimental results. In addition, paths (ii) and (iii) are found to be competitive with each other and both are highly energetic due to steric effects, with activation energy being about 50 kcal/mo!

MIND0/3 Study of the \u27Thermal Rearrangements of Bicyclobutanylidene

It is found that path (i), which is concerted and stereospecific, is favored both thermodynamically and kinetically, in agreement with exp~\u27rimental results. In addition, paths (ii) and (iii) are found to be competitive with each other and both are highly energetic due to steric effects, with activation energy being about 50 kcal/mo!

Simulation Study of a Gramicidin/Lipid Bilayer System in Excess Water and Lipid. II. Rates and Mechanisms of Water Transport

AbstractA gramicidin channel in a fluid phase DMPC bilayer with excess lipid and water has been simulated. By use of the formal correspondence between diffusion and random walk, a permeability for water through the channel was calculated, and was found to agree closely with the experimental results of Rosenberg and Finkelstein (Rosenberg, P. A., and A. Finkelstein. 1978. J. Gen. Physiol. 72:327–340; 341–350) for permeation of water through gramicidin in a phospholipid membrane. By using fluctuation analysis, components of resistance to permeation were computed for movement through the channel interior, for the transition step at the channel mouth where the water molecule solvation environment changes, and for the process of diffusion up to the channel mouth. The majority of the resistance to permeation appears to occur in the transition step at the channel mouth. A significant amount is also due to structurally based free energy barriers within the channel. Only small amounts are due to local friction within the channel or to diffusive resistance for approaching the channel mouth

Trajectories of alcohol-related harm among young people

In many high-income countries such as Australia, alcohol use has declined in young people since the early 2000s but there is conflicting evidence around reductions in alcohol-related harm. A key issue around quantifying alcohol-related harm is that different data sources can show vastly different patterns due to varying sample characteristics or methods of measurement. The studies comprising this thesis aimed to address these gaps by using a variety of data sources to examine: 1) trends in self-reported harms across age, period, and birth cohort using national surveys (n=121,281); 2) developmental patterns of blackouts, a very common harm, and predictors of high-risk patterns in a recent birth cohort (n=1,821); 3) developmental transitions between different types of alcohol-related harm and predictor of high-risk patterns in a recent birth cohort (n=1,828); and 4) risk factors for experiencing clinical alcohol-related harm for the first time at a younger age and compare rates of subsequent harm by age at first experience of clinical harm in a linked cohort (n=10,300). Several notable findings were identified. National data indicate that alcohol-related risky behaviours are much less common in recent birth cohorts, though they continue to be most prevalent in young people. Males generally had twice the prevalence of risky behaviours compared to females, but with reduced effect among more recent birth cohorts. Longitudinal cohort data indicated that escalating experience of harms, particularly blackouts and psychosocial harms (e.g., getting into fights) increased risk of early adulthood alcohol use disorder symptoms. Females were at higher risk of experiencing physiological harms such as blackouts earlier in life compared to males. Finally, analyses of linked hospital service data indicated that females were at higher risk of accessing hospital services for an alcohol-related problem for the first time at a younger age. Younger people were more likely to have subsequent injury-related ED presentations but less likely to be hospitalised. Past year hospital service access rates in this cohort were much higher than the same-aged general population. This thesis highlights important developments in young peoples’ experience of alcohol-related harm. The identification of a closing male-female gap in harms and of female status as a risk factor for early harm warrants future research and shifts to the approach of harm reduction and prevention among young people

An Exploratory Study on the Impact of Trust on Different E-Payment Gateways: Octopus Card Vs. Credit Card

The study of trust of consumer on Business-to-Consumer (B2C) E-commerce is one of the key research interests of Information Systems (IS) researchers. In this research, we investigate the impact of trust on two different E-payment gateways, viz. online credit card payment system and the hypothetical online Octopus card (a stored-value smart card) payment system. Based on the model developed by Gefen et al. (2003) and McKnight et al. (2002a), we synthesize our own research model by incorporating disposition to trust, and trust and its antecedents with the Technology Acceptance Model (TAM). An online survey was conducted on the Government-to-Citizen (G2C) E-commerce portal of the Hong Kong Government and 2,481 usable responses were collected. The empirical result shows that consumers in Hong Kong are using different trust building processes to consider their adoption for E-payment gateways

MNDO Study of Helvetane and Israelane

Applying MNDO approximatlon, the heats of formation (LlHt) and structures of the navel compounds helvetane (1) and israelane (2) have been calculated. The MNDO sn, for 1 and 2 are 336 and 719 kcal/mol, respectively, in agreement with the previous prediction that 1 is more stable than 2. In addition, in view of the structures calculated, the large positive LlHt values of 1 and 2 are most likely the result of these malecules\u27 angular strain

Improving predicted protein loop structure ranking using a Pareto-optimality consensus method

<p>Abstract</p> <p>Background</p> <p>Accurate protein loop structure models are important to understand functions of many proteins. Identifying the native or near-native models by distinguishing them from the misfolded ones is a critical step in protein loop structure prediction.</p> <p>Results</p> <p>We have developed a Pareto Optimal Consensus (POC) method, which is a consensus model ranking approach to integrate multiple knowledge- or physics-based scoring functions. The procedure of identifying the models of best quality in a model set includes: 1) identifying the models at the Pareto optimal front with respect to a set of scoring functions, and 2) ranking them based on the fuzzy dominance relationship to the rest of the models. We apply the POC method to a large number of decoy sets for loops of 4- to 12-residue in length using a functional space composed of several carefully-selected scoring functions: Rosetta, DOPE, DDFIRE, OPLS-AA, and a triplet backbone dihedral potential developed in our lab. Our computational results show that the sets of Pareto-optimal decoys, which are typically composed of ~20% or less of the overall decoys in a set, have a good coverage of the best or near-best decoys in more than 99% of the loop targets. Compared to the individual scoring function yielding best selection accuracy in the decoy sets, the POC method yields 23%, 37%, and 64% less false positives in distinguishing the native conformation, indentifying a near-native model (RMSD < 0.5A from the native) as top-ranked, and selecting at least one near-native model in the top-5-ranked models, respectively. Similar effectiveness of the POC method is also found in the decoy sets from membrane protein loops. Furthermore, the POC method outperforms the other popularly-used consensus strategies in model ranking, such as rank-by-number, rank-by-rank, rank-by-vote, and regression-based methods.</p> <p>Conclusions</p> <p>By integrating multiple knowledge- and physics-based scoring functions based on Pareto optimality and fuzzy dominance, the POC method is effective in distinguishing the best loop models from the other ones within a loop model set.</p

End-to-end models of marine ecosystems: exploring the consequences of climate change and fishing using a minimal framework

Marine ecosystems are vital to human society: as a source of food, for economic growth and for their potential to mitigate climate change. With marine ecosystems threatened by climate change and overfishing, there is a need for sustainable fisheries management, which has been the basis for an ecosystem-based approach to management. This has led to considerable interest in end-to-end ecosystem models, where the physical effects of the environment and the population dynamics of all marine organisms are coupled together into one framework. In this thesis, I studied an end-to-end model which coupled together a box-component model representing phytoplankton and zooplankton, with a size-structured fish community model. I investigated the potential artefacts in model results, caused by numerical methods or by model architecture. I found that care needs to be taken with the choice of numerical method used to simulate size-structured models, as the choice of numerical resolution can yield numerically stable results but can also affect large-scale behaviours of the system, such as the slope and mathematical stability of the size-spectra solutions. With regards to model architecture, coupling together two submodels which differ in structure and resolution can lead to large-scale behaviours of the system which appear plausible and consistent with empirical data, but which impose serious discrepancies in the underlying life-histories of the fish. By distinguishing model artefacts from ecosystem-effects, the interactions and feedbacks between the higher and lower trophic level organisms can be investigated. I studied the potential impact of climate change upon the marine ecosystem, and in particular, upon the seasonal dynamics of phytoplankton. I found that under a warming climate, the spring phytoplankton bloom occurs earlier and for a longer duration, and the model predicts the loss of the autumn phytoplankton bloom. These changes were not solely due to the direct effect of temperature, but also due to the indirect effect of the interactions of the fish population with zooplankton. The effect of fishing upon the marine ecosystem was also explored with this end-to-end model, with two potential fishing strategies applied to the system. Regardless of the choice of fishing strategy, intensive exploitation of fish stocks can lead to a significant shift in the dynamics of phytoplankton. The phytoplankton's dynamics change from stable annual patterns to unpredictable periodic behaviours. This thesis has developed an end-to-end model which uses a minimal framework to study the interactions of organisms at different trophic levels, and highlights the importance of these interactions and the associated feedbacks under different scenarios. It combines important theoretical insights into the consequences of model architecture and model-derived artefacts upon ecosystem-scale behaviours, at the same time as highlighting the potential for end-to-end models as a practical and flexible management tool

Improving Nurses’ Corrected QT Interval Monitoring on a Telemetry Unit

D.N.P

Stereotactic Electroencephalography (SEEG)

Drug resistant epilepsy (DRE) is not an uncommon clinical condition. DRE could cause disabling seizures and even sudden unexpected death in epilepsy (SUDEP). Pre-surgical evaluation is necessary to for surgical treatment to cure or palliative epilepsy. If feasible, surgical excision of an epileptic focus provides the best chance of cure. However, the standard non-invasive workup could not always identify the epileptic focus. Stereotactic EEG (SEEG) is an invasive EEG that could provide the spatial and temporal progression of epileptic discharge so that we could localize or lateralise the epileptic focus more easily. This chapter aims to illustrate the principle of SEEG, the methods of SEEG electrode insertion, the usual white matter tract pathway that epileptic discharge progresses. It also discusses the therapeutic use of SEEG in lesioning with radiofrequency ablation (RFA), as well as the future potential as part of the brain-computer interface (BCI)