Post Production Heavy Oil Operations: A Case for Partial Upgrading

The transportation of heavy oil is a pressing problem. Various methods have been devised to mitigate the reluctance to flow of these highly dense and viscous oils. This study is focused on evaluating a case for post-production partial upgrading of heavy oil. Specifically, we analyze the impact of visbreaking, a mild thermal cracking method, on the economic and energy demands of the post-production process. Using conservative modeling techniques and principles we find significant cost and energy savings can potentially result out of visbreaking. Cost savings result as a consequence of reduced diluent usage. Even the most conservative modeling scenario under consideration exhibits significant cost savings in the form of reduced diluent usage; these savings not only offset operational costs but provide short payback periods on capital expenditures. Additionally, the lower gravity blend resulting from visbreaking can also bring about energy and cost savings in pipeline transportation and positively impact the heavy oil value chain from the producer to a refinery or regional upgrading facility. From this basic analysis of the potential of visbreaking, we can recommend investing resources to study its viability in the field. Using this analysis as a tipping off point and with a detailed look at the chemistry of the oil in question it is possible to make a very viable case for visbreaking. In a similar vein, this analysis can serve as a guide in making a case for other partial upgrading methods as well

Associations between early childhood sleep, memory function, and brain development across the nap transition

Preschool-age children often distribute their sleep across a midday nap and overnight sleep. Skipping the nap is suggested to increase the duration and depth of deep sleep (i.e., slow wave activity; SWA). Moreover, missing the midday nap has been shown to impair learning processes. This may be because children’s brains at this point in development are immature, necessitating the intervening nap period to strengthen memories before they are forgotten. Nonetheless, at some point during the preschool years, many children begin transitioning naturally out of napping. It is unclear whether the memory benefits of overnight SWA after a skipped nap depend on children’s baseline nap frequency. To this end, Chapter 2 of my dissertation sought to examine how the consolidation of memory over nocturnal sleep changes across the nap transition. Habitually and non-habitually napping children were taught a declarative task in the afternoon, and memory was probed following a polysomnography-monitored nap and following an equivalent period of wake. Memory was also examined 24-hours later in the afternoon following polysomnography-monitored overnight sleep. While children performed better over overnight sleep had they been awake during nap time the day prior, performance was not related to overnight SWA. However, when SWA was divided into slow and fast SWA, both measures were negatively associated with performance following overnight sleep. While it is known that children transition out of naps, the mechanism behind this transition is unclear. Considering that early childhood is a time of significant changes in both sleep and the brain, it is possible that the cessation of napping may have to do with brain development. To this end, Chapter 3 examined the relations between changes in SWA and hippocampal body volume longitudinally. Hippocampal body volume decreased over time, for both habitual nappers and those who transitioned out of the nap. However, SWA decreased over time only for children who transitioned out of naps. Collectively, the results of this dissertation suggest that the transition out of napping may be indicative of more mature brains (Chapter 3) and therefore a single overnight bout of sleep may be efficient for the consolidation of memories (Chapter 2)

Slow Wave Sleep in Naps Supports Episodic Memories in Early Childhood

Naps have been shown to benefit declarative memories in early childhood. This benefit has been associated with sleep spindles during the nap. However, whether young children’s naps and their accompanying physiology benefit other forms of declarative learning is unknown. Using a novel storybook task, we found performance was better following a nap compared to performance following an equivalent interval spent awake. Moreover, performance was better the following day if a nap followed learning. Further, change in post-nap performance was positively associated to the amount of time spent in slow wave sleep. This suggests that slow wave sleep in naps may support episodic memory consolidation in early childhood. Taken in conjunction with prior work, these results suggest that multiple features of brain physiology during naps may contribute to declarative memory processing in early childhood

A data gathering toolkit for biological information integration

SYSTERS is a biological information integration system containing protein sequences from many protein databases such as Swiss-Prot and TrEMBL and also protein sequences from complete genomes available at Ensembl, The Arabidopsis Information Resource, SGD and GeneDB. For some protein sequences their encoding nucleotide sequences can be found in their corresponding websites. However, for some protein sequences their encoding nucleotide sequences are missing. The goal of this thesis is to. collect all nucleotide sequences for the protein sequences in SYSTERS and store them in a common database. There are two cases. The first case is that if the nucleotide sequences can be found, we collect them and put them in our database. The second case is that if the nucleotide sequences are missing, we use back-translation and use TBLASTN to search the nucleotide sequences and store them in our database

Analysis of vehicle suspension system subjected to random vibration

A two dimensional, two degree of freedom vehicle model is studied. A randomly profiled road is assumed to impart hyperbolic distributed stationary vertical random displacements to the front and the rear wheel. A computer program has been developed to evaluate transfer function matrices. The performance characteristic of the vehicle based on the Power Spectral Density of the vertical acceleration as well as the rattle space, for different values of damping factors, are studied

Do Statins Improve Outcomes in Patients With Asthma on Inhaled Corticosteroid Therapy? A Retrospective Analysis of the Mississippi Medicaid Database 2002-2004.

Animal model studies and clinical trials have looked at the potential benefits of the anti-inflammatory properties of statins in asthma management with contradictory results. Therefore, the objective of this study is to determine if asthma patients on concurrent statin therapy are less likely to have asthma-related hospitalizations and emergency room (ER) visits. We conducted a retrospective cohort study using Medicaid data for 2002–2004. Asthma patients ?18 years old were identified using the ICD9 code 493.xx, from Jul 1, 2002 through Dec 31, 2003. The index date for an exposed subject was any date within the identification period, 180 days prior to which the subject had at least 1 inhaled corticosteroid (ICS) prescription and at least an 80% adherence rate to statins. Medicaid beneficiaries identified as asthmatics and on ICS therapy, but not on statins were selected as the unexposed population. Each subject in the exposed group was matched to 2 subjects from the unexposed population using propensity scores computed using age, gender, race, urban/rural region and Charlson Comorbidity Index. The two groups were follofor 1 year beginning on the index date, and their outcomes in terms of hospitalizations and ER visits were compared using conditional logistic regression, further adjusted for adherence to ICS therapy, average number of short-acting ? agonists per subject, prior hospitalizations, ER, lab and office visits due to asthma. After matching, there were 479 exposed subjects with 958 corresponding controls. After adjusting for the above mentioned covariates, asthma patients not on concurrent statin therapy are almost two times as likely to have hospitalization and/or ER visits or both due to asthma (adjusted OR = 0.55; 95% CI [0.37, 0.84]; p = 0.0059), in comparison to patients on statin therapy. Similarly, they are also twice as likely to visit the ER due to asthma exacerbations as patients on statins (adjusted OR = 0.48; 95% CI [0.28, 0.82]; p = 0.0069). The findings of this study suggest that there may be beneficial effects of statins in preventing asthma exacerbations. Further prospective investigations are required to provide conclusive evidence

Impact Of Time-Varying And Time-Invariant Measures Of Adherence To Secondary Prevention Therapies Post-Acute Myocardial Infarction: An Application Of Marginal Structural Models (MSMS)

The purpose of the study was to explore the relationship between patient adherence to secondary prevention therapies post an initial episode of acute myocardial infarction (AMI) and subsequent risk of cardiovascular events by using time-invariant and time-varying measures of adherence. The effectiveness of both measures in predicting a (i) recurrent AMI, and (ii) mortality using various mathematical models and statistical techniques was compared. Time dependent confounding was accounted for by using marginal structural models (MSMs). A longitudinal cohort observational study design was employed using the retrospective Medicare 5% random national sample claims data from January 1st, 2006 to December 31st, 2008. The time-invariant measure of adherence was measured over a fixed one year period. Time-varying adherence was measured quarterly along with other time-varying confounders over a maximum follow-up of 11 quarters. Estimates of the effect of adherence from Cox regression models and MSMs were compared, along with model-fit-statistics. Of the total 1,427 patients included in the study, cohort A (statin therapy) comprised of 1,091 patients, and cohorts B (β-blocker therapy) and C (angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) therapy) included 1,021 and 1,025 patients, respectively. When accounting only for baseline covariates in a discrete-event time model the hazard for a recurrent AMI among statin adherent patients in cohort A was 63% of the hazard among non-adherent patients (Hazard Ratio (HR) = 0.63; 95% CI [0.40, 0.99]; p = 0.0471). When accounting for baseline covariates and time-varying covariates in a discrete-event time model the hazard for a recurrent AMI among statin adherent patients in cohort A was 61% of the hazard among non-adherent patients (HR = 0.61, 95% CI [0.38, 0.97]; p = 0.0366). The results for the effect of adherence to β-blockers and ACEI/ARBs on subsequent cardiovascular events were not statistically significant. The stabilized weights used in estimation of the MSMs did not have optimum variability and the results from the MSMs were not statistically significant. Further studies are required to understand if MSMs should be the preferred methodology when exploring the relationship between long-term medication adherence and health outcomes

Development of Adenovirus-vectored Prototype Vaccines for African Swine Fever Virus and Bovine Viral Diarrhea Virus

The objective of this work was to develop adenovirus-vectored prototype vaccines against two pathogens, African Swine Fever Virus (ASFV) and Bovine Viral Diarrhea Virus (BVDV), which cause disease in two major livestock species, swine and cattle respectively. The African Swine Fever Virus is a transboundary animal pathogen that causes a lethal hemorrhagic fever in domestic pigs. Attempts to develop a vaccine for ASFV have failed thus far. This manuscript describes the use of recombinant adenovirus to deliver two unique formulations of ASFV antigens in swine (in two separate in-vivo studies) and the subsequent evaluation of the antigen-specific antibody and cellular responses induced. The robust antigen-specific immune responses observed in both studies are promising and their protective potential will be evaluated in future efficacy studies The Bovine Viral Diarrhea Virus is a globally prevalent pathogen that can cause severe diarrhea, respiratory disease, abortions and sometimes death in calves. Killed and modified live vaccines (MLV) for BVDV have been in use since the 1960s but are not effective due to lack of cross-protection and retention of immunosuppressive characteristics. This thesis also describes the use of the recombinant adenovirus vector to deliver a cocktail of multiple mosaic BVDV antigens in calves followed by the evaluation of protection conferred upon challenge. The prototype vaccine was more immunogenic and cross-protective (based on neutralizing antibodies) than a commercial MLV BVDV vaccine. Regarding protective efficacy, all calves immunized with prototype vaccine cleared the virus within a week post-challenge, whereas one calf that received the MLV vaccine still remained viremic. Future efficacy studies with diverse BVDV strains are required to validate the cross-protective potential of this prototype vaccine

Issues in QT interval measurement

The QT interval, apart from clinical implications is crucial for safety assessment of new drugs under development. A QTc prolongation of even 10 msec in a study group is a warning signal for a new drug. There are various issues involved in the measurement of the QT interval especially regarding the ending of the T wave and different morphological pattern of T-U complex. The other issue is significant spontaneous variability in the QT interval, resulting in spurious QT prolongation and unnecessary concern. To minimize all these confounding factors, all clinical trials for assessing QT interval prolongation should be randomized and double blinded with appropriate control groups including placebo. ECG measurements should be done by trained readers with electronic calipers at ECG core Lab. ECGs should be compared with multiple baseline values with multiple, time-matched on-treatment values