Hydrotreating of Gas Oils Using Ni-Mo Catalyst Supported on Carbon Nanohorns and Associated Carbon Materials

For many decades, crude oil refinery companies and catalysis research establishments worldwide are being challenged to develop new hydrotreating processes aimed at producing cleaner fuel. Use of an active and stable catalyst in hydrotreating is one way of improving catalytic activity of hydrotreating reactions such as hydrodesulfurization (HDS) and hydrodenitrogenation (HDN). Hence, this research primary goal is to develop a NiMo catalyst supported on carbon nanohorns (CNH) and associated carbon materials for hydrotreating. CNH is the support of choice used in this research due to its inert nature and excellent textural properties (mesoporosity, high surface area and desirable pore volume) which are known to enhance hydrotreating activities. The research plan is divided into five phases, and the research goals, experimental methods and outcomes pertaining to each of the phases are summarized in this thesis. For phase one, the goal was to maximize the production of CNH in the lab for hydrotreating application by investigating the effects of, current settings, processing time and equipment design on CNH production. A current setting of 90 A and 30 minutes processing time were determined to be the best conditions for laboratory scale maximization of CNH production. In phase two, the primary aim was to incorporate functionality in an otherwise inert CNH material using, 30 wt% HNO3 under reflux for 15 minutes to 4 hours at 110°C. Production of CNH concurrently generates other carbon particles (OCP) as by-products that can be differentiated into fine (OCPf) and chunk (OCPc) forms. Due to the superior quality of the CNH material in phase three, the goal was to test the influence of four different supports (i.e. gamma-alumina (γ-Al2O3), CNH, OCPf, and carbon nanotubes (CNT)) on hydrotreating performance, and to determine how the physico-chemical properties of each support has on the hydrotreating performance. In comparison to the remaining carbon-supported catalysts, NiMo/CNH catalyst exhibited higher HDS (89%) and HDN (42%) activities for light gas oil containing 3 wt% sulfur and 0.18 wt% nitrogen and this is ascribed to, the high textural properties of the NiMo/CNH catalyst as well as its ability to induce, high metal dispersion plus reduction of metal oxides at a lower temperature in comparison to the remaining carbon-supported catalysts. The yield of OCP material from the laboratory synthesis of CNH was more than 45% of the CNH yield. Moreover, from phase three, OCPf support was also found to be a viable support in hydrotreating hence, the main focus of phase four work was to improve the hydrotreating performance of NiMo/OCPf catalyst by varying Ni and Mo compositions on the functionalized OCPf support. To this effect, a series of hydrotreating experimental runs with varying Ni (2.5, 3.5, 5.0 wt%) and Mo (13, 19, 26 wt%) compositions with light gas oil indicated that 5.0wt%Ni19wt%Mo/OCPf catalysts exhibited the highest HDS and HDN activity. The last phase (phase 5) of the research plan focused on the development of the best NiMo/CNH catalyst for hydrotreating by varying Ni loadings (2.5 wt%, - 5 wt%) at constant Mo loading of 19 wt%. Hydrotreating results from these catalysts showed that, the 3.5wt%Ni19wt%Mo/CNH catalyst exhibited the highest HDS and HDN activity. This catalyst was further modified by adding 2 wt% P to the 3.5 wt% Ni and 19 wt% Mo concentrations via a co-impregnation method to study the effects of phosphorus as a secondary promoter on HDS and HDN activity. Optimization of the operating parameters, kinetic and stabilization studies were further carried out using the 3.5wt%Ni19wt%Mo/CNH catalyst. The results from this phase are also presented in this thesis. The overall results from all phases demonstrated that CNH is not only a material that have superior physicochemical properties as compared to CNT and OCP material but, also a potential catalyst support with great benefit in hydrotreating

Climate change and the mitigating tool of salvage archaeology: The case of the Fort Kongensten site at Ada Foah, Ghana

In the ongoing attempts at lessening the hydra-headed impacts of climate change, this paper explored the strategic use of salvage archaeology in the scientific retrieval and documentation of heritage remains and sites under the threat of climate change. In doing so, the research examined the effects of climate change and global warming on coastal heritage resources. Specifically, in Ghana, sea levels have been steadily rising over the centuries leading to the erosion of coastlines and the submergence of historic coastal settlements to about 110 metres inland. A historic Danish Fort Kongensten constructed in 1783 along the coast of Ada-Foah in Ghana, for example, has been totally eroded away by the rising sea water. This paper assesses how salvage archaeology was used to retrieve, document and conserve cultural materials associated with the fort. It also explored the extent to which salvage archaeology and anthropology can be used as tools in climate change mitigation projects in impacted zones

A cell epigenotype specific model for the correction of brain cellular heterogeneity bias and its application to age, brain region and major depression

Brain cellular heterogeneity may bias cell type specific DNA methylation patterns, influencing findings in psychiatric epigenetic studies. We performed fluorescence activated cell sorting (FACS) of neuronal nuclei and Illumina HM450 DNA methylation profiling in post mortem frontal cortex of 29 major depression and 29 matched controls. We identify genomic features and ontologies enriched for cell type specific epigenetic variation. Using the top cell epigenotype specific (CETS) marks, we generated a publically available R package, “CETS,” capable of quantifying neuronal proportions and generating in silico neuronal profiles from DNA methylation data. We demonstrate a significant overlap in major depression DNA methylation associations between FACS separated and CETS model generated neuronal profiles relative to bulk profiles. CETS derived neuronal proportions correlated significantly with age in the frontal cortex and cerebellum and accounted for epigenetic variation between brain regions. CETS based control of cellular heterogeneity will enable more robust hypothesis testing in the brain

Risk factors for active trachoma in The Gambia.

Trachoma has been endemic in The Gambia for decades but national surveys indicate that the prevalence is falling. Risk factor data can help guide trachoma control efforts. This study investigated risk factors for active trachoma and ocular Chlamydia trachomatis infection in children aged below 10 years in two Gambian regions. The overall prevalence of C. trachomatis infection was only 0.3% (3/950) compared with 10.4% (311/2990) for active trachoma, therefore analyses were only performed for active trachoma. After adjustment, increased risk of trachoma was associated with being aged 1-2 years (odds ratio (OR) 2.20, 95% CI 1.07-4.52) and 3-5 years (OR 3.62, 95% CI 1.80-7.25) compared with <1 year, nasal discharge (OR 2.07, 95% CI 1.53-2.81), ocular discharge (OR 2.68, 95% CI 1.76-4.09) and there being at least one other child in the household with active trachoma (OR 11.28, 95% CI 8.31-15.31). Compared with other occupations, children of traders had reduced risk (OR 0.53, 95% CI 0.30-0.94). At the household level, only the presence of another child in the household with active trachoma was associated with increased risk of active trachoma, suggesting that current trachoma control interventions are effective at this level. In contrast, child-level factors were associated with increased risk after adjustment, indicating a need to increase control efforts at the child level

Methylergometrine Poisoning In The Newborn: Report Of Two Cases

Methylergometrine is probably the most commonly used drug in obstetric care at all levels of the health care system. Many communities in Africa lack skilled birth attendants and adequate health systems; medication errors are more likely to occur and go unreported in these settings. The morbidity and mortality that result from these errors can be reduced if health care workers are better informed. We report two cases of medication error with methylergometrine and suggest guidelines for health care workers at the primary and secondary levels of health care

Opportunities to reduce antibiotic prescribing for patients with COPD in primary care: a cohort study using electronic health records from the Clinical Practice Research Datalink (CPRD)

Background In primary care there is uncertainty about which patients with acute exacerbations of COPD (AECOPD) benefit from antibiotics. Objectives To identify which types of COPD patients get the most antibiotics in primary care to support targeted antibiotic stewardship. Methods Observational study of COPD patients using a large English primary care database with 12 month follow-up. We estimated the incidence of and risk factors for antibiotic prescribing relative to the number of AECOPD during follow-up, considering COPD severity, smoking, obesity and comorbidity. Results From 157 practices, 19594 patients were diagnosed with COPD, representing 2.6% of patients and 11.5% of all prescribed antibiotics. Eight hundred and thirty-three (4.5%) patients with severe COPD and frequent AECOPD were prescribed six to nine prescriptions per year and accounted for 13.0% of antibiotics. Individuals with mild to moderate COPD and zero or one AECOPD received one to three prescriptions per year but accounted for 42.5% of all prescriptions. In addition to COPD severity, asthma, chronic heart disease, diabetes, heart failure and influenza vaccination were independently associated with increased antibiotic use. Conclusions Patients with severe COPD have the highest rates of antibiotic prescribing but most antibiotics are prescribed for patients with mild to moderate COPD. Antibiotic stewardship should focus on the dual goals of safely reducing the volume of prescribing in patients with mild to moderate COPD, and optimizing prescribing in patients with severe disease who are at significant risk of drug resistance

Combining work and child care: The experiences of mothers in Accra, Ghana

Work-family research has focused predominantly on Western women. Yet the forms of economic labour in which women are typically involved and the meaning of motherhood are context-specific. This paper aims to explore the experience of combining economic activity and child care of mothers with young children using urban Ghana as a case study. Semi-structured interviews (n=24) were conducted in three locations in the Accra Metropolitan Area. Transcripts were analysed using the general inductive approach. The results found women’s experience of role conflict to be bi-directional. With regard to role enhancement, economic activity allowed women to provide materially for their children. The combination of work and child care had negative consequences for women’s wellbeing. This research questions policy makers’ strategy of frequently targeting women in their roles either as generators of income, or as the primary care-takers of children by highlighting the reality of women’s simultaneous performance of these roles

An improved empirical bayes approach to estimating differential gene expression in microarray time-course data: BETR (Bayesian Estimation of Temporal Regulation)

<p>Abstract</p> <p>Background</p> <p>Microarray gene expression time-course experiments provide the opportunity to observe the evolution of transcriptional programs that cells use to respond to internal and external stimuli. Most commonly used methods for identifying differentially expressed genes treat each time point as independent and ignore important correlations, including those within samples and between sampling times. Therefore they do not make full use of the information intrinsic to the data, leading to a loss of power.</p> <p>Results</p> <p>We present a flexible random-effects model that takes such correlations into account, improving our ability to detect genes that have sustained differential expression over more than one time point. By modeling the joint distribution of the samples that have been profiled across all time points, we gain sensitivity compared to a marginal analysis that examines each time point in isolation. We assign each gene a probability of differential expression using an empirical Bayes approach that reduces the effective number of parameters to be estimated.</p> <p>Conclusions</p> <p>Based on results from theory, simulated data, and application to the genomic data presented here, we show that BETR has increased power to detect subtle differential expression in time-series data. The open-source R package <it>betr </it>is available through Bioconductor. BETR has also been incorporated in the freely-available, open-source MeV software tool available from <url>http://www.tm4.org/mev.html</url>.</p

Shale Gas Development and Community Distress: Evidence from England

This research examines psychosocial stress associated with shale gas development through the narratives of residents and the Revised Impact of Event Scale (IES-R). We carried out our research in three of England&rsquo;s communities impacted by shale gas development. To gather data, we conducted qualitative interviews and engaged in participant observation in all three communities and conducted a quantitative survey of residents. From our qualitative interviews it was apparent that the residents we spoke with experienced significant levels of stress associated with shale gas development in each community. Importantly, residents reported that stress was not only a reaction to development, but a consequence of interacting with industry and decision makers. Our quantitative findings suggest that a significant portion of residents 14.1 living near the shale gas sites reported high levels of stress (i.e., scoring 24 or more points) even while the mean IES-R score of residents living around the site is relatively low (i.e., 9.6; 95 CI 7.5&ndash;11.7). We conclude that the experiences, of the three English communities, reported in the qualitative interviews and quantitative survey are consistent with the reports of stress in the United States for those residents who live in shale gas communities. We therefore suggest that psychosocial stress is an important negative externality, which needs to be taken seriously by local planning officers and local planning committees when considering exploration and development permits for shale gas

diffloop: a computational framework for identifying and analyzing differential DNA loops from sequencing data

Abstract Summary The 3D architecture of DNA within the nucleus is a key determinant of interactions between genes, regulatory elements, and transcriptional machinery. As a result, differences in DNA looping structure are associated with variation in gene expression and cell state. To systematically assess changes in DNA looping architecture between samples, we introduce diffloop, an R/Bioconductor package that provides a suite of functions for the quality control, statistical testing, annotation, and visualization of DNA loops. We demonstrate this functionality by detecting differences between ENCODE ChIA-PET samples and relate looping to variability in epigenetic state. Availability and implementation Diffloop is implemented as an R/Bioconductor package available at https://bioconductor.org/packages/release/bioc/html/diffloop.html Contact [email protected] Supplementary information Supplementary data are available at Bioinformatics online