Towards The Development of Biosensors for the Detection of Microbiologically Influenced Corrosion (MIC)

Corrosion is one of the biggest concerns for mechanical integrity of infrastructure and infrastructural components, such as oil refineries, bridges and roads. The economic cost of corrosion is typically estimated to be between 1 to 5 % of the gross national product (GNP) of countries, of which the contribution of microbiologically influenced corrosion (MIC) is estimated to be between 10% and 50%. Current state-of-the-art approaches for detecting MIC primarily rely on ex-situ tests, including bacterial test kits (bug bottles); corrosion coupons, pigging deposits analysis and destructive analysis of MIC affected sites using SEM, TEM, and XRD. These ex-situ measurements do not capture the complexities and time sensitivities underlying MIC. This is owed to the fact that the proliferation of the microbial contamination is a dynamic and rapid process, and any delay can prove expensive as it is estimated that once the biofilm formation takes place the amount of biocides needed is magnitude of orders more as compared to when the bacteria are in planktonic form. Additionally, the field environment is a complex biotic and abiotic environment which is often difficult to replicate even in high fidelity laboratory models. Hence a real-time/pseudo real-time method of detection would greatly help reduce the costs and optimize biocide-based mitigation of MIC. To overcome the above-mentioned shortcomings associated with the state-of-the-art; this work is aimed at the development of a sensor substrate whereby highly specific detection can be carried out in the environment where the corrosion exists, in a real-time/pseudo real-time basis. More specifically, the research is aimed at the development of sensors based on a nanowire matrix functionalized with biomolecules which can perform this specific and real-time detection of MIC in the pipeline environment. Here, the detection of MIC is based on the binding of specific biomolecules causing MIC to organic molecules anchored on top of the nanowires. These sensors also need to be inexpensive (made of low-cost, earth abundant materials), have low power consumption, and robustly deployable. The primary component of the detection platforms are copper oxide nanowire arrays (CuONWs with lengths of 25 to 30 m, 50 to 100 nm in diameter) and silicon nanowires arrays (SiNWs with lengths of 5 to 8 m, 45 to 100 nm in diameter). They are synthesized using facile and scalable techniques and are selected for their robust electrical and mechanical properties. Electrochemical degradation studies of the NWs were performed in 3.5 wt. % NaCl solution and simulated produced water using polarization and electrochemical impedance spectroscopy (EIS). The NWs systems showed robust resistance to degradation despite higher surface area (as compared to bulk counterparts), and both diffusion limitations and charge transfer resistance was observed on the analysis of the impedance response. The ability to immobilize a variety of moieties on the nanowire platforms gives them the ability to detecting a wide variety of MIC biomarkers. The Biotin-Streptavidin (SA) complex was used as a proof of concept to test the viability of the NW arrays as a substrate for sensing. A custom test bed was built for the functionalized NW thin films, and cyclic voltammetry studies revealed a stable current response with time for 10nM and 10,000 nM SA concentrations. The use of different probes such as aptamers to larger immunoglobulin probes provides the flexibility to detect the full spectrum of biomarkers. The development of these next generation sensor platforms along with the methodologies employed to stabilize them and assemble them into functional devices are explored in detail in this dissertation

Fatigue monitoring in offshore energy operations: Research to Practice gaps

PresentationThe oil and gas extraction (OGE) industry continues to experience an elevated fatality rate; from 2010-2014 fatality the rate in this industry was nearly seven times higher than that for all U.S. workers. OGE workers are exposed to intensive shift patterns and long work durations inherent in the OGE environment, which can lead to fatigue, thereby increasing risks of accidents and injuries. Fatigue, often defined as a physiological state of reduced mental or physical performance capability resulting from sleep loss, circadian phase, and workload, has been implicated as a critical risk in both offshore and onshore OGE operations. The aims of this study were to explore the effect of offshore shiftwork on physiological and subjective fatigue outcomes. 10 male workers (age: 31.3 (6.1) years; stature: 1.72 (0.1) m; weight: 85.24 (9.8) kg) were monitored throughout their daily shifts for six days using intrinsically safer physiological sensors (EQ02 LifeMonitor, EquivitalTM, Cambridge, UK) that recorded various physiological parameters at 250Hz and subjective fatigue scales were employed to obtain perceptions of fatigue. Results indicate that overall average ambulatory heart rate (an indicator of fatigue) were elevated for all participants and was highest and raised the most for those who started and ended their hitch on the day shift. The same measure was lowest and did not change for those who started on the day shift and swung to the night shift. The ambulation rates (a measure of movement) were higher later in the participants’ hitch and this effect was seen primarily for those who started their hitch in the day shift. Participants’ reports of fatigue were relatively high for acute fatigue and intershift recovery as well as for lack of effort and sleepiness; however, the physiological measures were not consistently or predictably correlated with the self-report measures of fatigue or activity. The study outcomes identified a critical gap in fatigue assessment in OGE operations; existing fatigue surveys for the general (or other) working populations are not comprehensive of OGE operations and are thus not applicable for OGE workers, nor are they validated against physiological fatigue outcomes in OGE workers

Development of an Effective Procedure Writer’s Guide using a Human Factors and Regulatory Compliance Approach

PresentationWell-written procedures are an integral part of any industrial organization for safe operation, managing risks, and continuous improvement. Regulatory bodies around the world require industries to have current, accurate, and appropriate procedures for most processes. Although the importance of procedures is recognized by all industries in general, significant incidents have occurred in the past due to procedural breakdowns. Some of the procedural breakdowns come from obvious problems such as the procedure not being available or the procedure being wrong. However, some incidents have occurred when correct procedures were available and the operator used those procedures. In these instances, the reason why operators do not follow procedures correctly may be attributable to many factors, one of them being that the procedure is presented or designed in a manner that does not sufficiently communicate to the operators the information that is needed in a manner that is easily and quickly understood. The work presented here is focused on the latter circumstance and is part of a program of research that will ultimately lead to the development of a writer’s guide for procedures that supports operators’ comprehension and compliance with all types of industrial procedures. The writer’s guide is based on empirical findings from human factors and human performance studies and provides writers with information on how to present procedures in a manner that is clear, thorough, and (if necessary) implementable with short notice. For the first phase of the project, a sample of the regulations and standards from several industries were used to identify procedure writing practices necessary for ensure regulatory compliance. Regulations and industrial standards from around the world were organized to reflect common ideas and the implications in terms of human factors needs were identified with regard to procedure design. Any human factors (HF) that had implications for the writer’s guide that had empirical support, were included in the writer’s guide (with the reference) with an explanation of the HF implication and empirical support. The writer’s guide developed is structured to allow procedure writers access to guidance on various types of procedures they are writing, the type of information they are trying to communicate, and methods for maintaining accurate and current procedures. As mentioned, the current project is the beginning of a program of research and then next phase will include feedback from operators regarding the challenges they face when using procedures

How Far Must You See To Hear Reliably

We consider the problem of probabilistic reliable communication (PRC) over synchronous networks modeled as directed graphs in the presence of a Byzantine adversary when players\u27 knowledge of the network topology is not complete. We show that possibility of PRC is extremely sensitive to the changes in players\u27 knowledge of the topology. This is in complete contrast with earlier known results on the possibility of perfectly reliable communication over undirected graphs where the case of each player knowing only its neighbours gives the same result as the case where players have complete knowledge of the network. Specifically, in either case, $(2t+1)$-vertex connectivity is necessary and sufficient, where $t$ is the number of nodes that can be corrupted by the adversary \cite{DDWY93:PSMT,SKR05}. We introduce a novel model for quantifying players\u27 knowledge of network topology, denoted by {$\mathcal TK$}. Given a directed graph $G$, influenced by a Byzantine adversary that can corrupt up to any $t$ players, we give a necessary and sufficient condition for possibility of PRC over $G$ for any arbitrary topology knowledge {$\mathcal TK$}. It follows from our main characterization theorem that knowledge of up to $d = \lfloor \frac{n - 2t}{3} \rfloor + 1$ levels is sufficient for the solvability of honest player to honest player communication over any network over which PRC is possible when each player has complete knowledge of the topology. We also show the existence of networks where PRC is possible when players have complete topology knowledge but it is not possible when the players do not have knowledge of up to $d = \lfloor \frac{n - 2t}{3} \rfloor + 1$ levels

CTLA4-Ig disrupts muscle fibrosis in the mdx mouse model of Duchenne muscular dystrophy

Despite advancements in our understanding of the immunobiology of Duchenne muscular dystrophy (DMD), previous findings were not translated into improvements in clinical practice. The standard clinical treatment for DMD includes administration of non-specific anti-inflammatory corticosteroids that provide limited benefits for patients and produce non-target effects that impair muscle regeneration. Thus, the search for an efficacious immunotherapy without adverse effects remains imperative. Because DMD pathology is exacerbated by fibrotic mechanisms mediated by myeloid and fibrogenic cells, we examined the effect of an immune suppressing fusion protein consisting of cytotoxic T-lymphocyte-associated protein4 and immunoglobulin G (CTLA4-Ig) in the mdx murine model of DMD. We found that CTLA4-Ig ameliorates pathology, via the disruption of fibrotic mechanisms, as treatment reduced collagen accumulation and expression in dystrophic muscle. These findings indicate that CTLA4-Ig treatment has inhibitory effects on profibrotic cells that exacerbate DMD pathology and could potentially serve as a promising treatment option for patients with DMD

Towards The Development of Biosensors for the Detection of Microbiologically Influenced Corrosion (MIC)

Corrosion is one of the biggest concerns for mechanical integrity of infrastructure and infrastructural components, such as oil refineries, bridges and roads. The economic cost of corrosion is typically estimated to be between 1 to 5 % of the gross national product (GNP) of countries, of which the contribution of microbiologically influenced corrosion (MIC) is estimated to be between 10% and 50%. Current state-of-the-art approaches for detecting MIC primarily rely on ex-situ tests, including bacterial test kits (bug bottles); corrosion coupons, pigging deposits analysis and destructive analysis of MIC affected sites using SEM, TEM, and XRD. These ex-situ measurements do not capture the complexities and time sensitivities underlying MIC. This is owed to the fact that the proliferation of the microbial contamination is a dynamic and rapid process, and any delay can prove expensive as it is estimated that once the biofilm formation takes place the amount of biocides needed is magnitude of orders more as compared to when the bacteria are in planktonic form. Additionally, the field environment is a complex biotic and abiotic environment which is often difficult to replicate even in high fidelity laboratory models. Hence a real-time/pseudo real-time method of detection would greatly help reduce the costs and optimize biocide-based mitigation of MIC. To overcome the above-mentioned shortcomings associated with the state-of-the-art; this work is aimed at the development of a sensor substrate whereby highly specific detection can be carried out in the environment where the corrosion exists, in a real-time/pseudo real-time basis. More specifically, the research is aimed at the development of sensors based on a nanowire matrix functionalized with biomolecules which can perform this specific and real-time detection of MIC in the pipeline environment. Here, the detection of MIC is based on the binding of specific biomolecules causing MIC to organic molecules anchored on top of the nanowires. These sensors also need to be inexpensive (made of low-cost, earth abundant materials), have low power consumption, and robustly deployable. The primary component of the detection platforms are copper oxide nanowire arrays (CuONWs with lengths of 25 to 30 m, 50 to 100 nm in diameter) and silicon nanowires arrays (SiNWs with lengths of 5 to 8 m, 45 to 100 nm in diameter). They are synthesized using facile and scalable techniques and are selected for their robust electrical and mechanical properties. Electrochemical degradation studies of the NWs were performed in 3.5 wt. % NaCl solution and simulated produced water using polarization and electrochemical impedance spectroscopy (EIS). The NWs systems showed robust resistance to degradation despite higher surface area (as compared to bulk counterparts), and both diffusion limitations and charge transfer resistance was observed on the analysis of the impedance response. The ability to immobilize a variety of moieties on the nanowire platforms gives them the ability to detecting a wide variety of MIC biomarkers. The Biotin-Streptavidin (SA) complex was used as a proof of concept to test the viability of the NW arrays as a substrate for sensing. A custom test bed was built for the functionalized NW thin films, and cyclic voltammetry studies revealed a stable current response with time for 10nM and 10,000 nM SA concentrations. The use of different probes such as aptamers to larger immunoglobulin probes provides the flexibility to detect the full spectrum of biomarkers. The development of these next generation sensor platforms along with the methodologies employed to stabilize them and assemble them into functional devices are explored in detail in this dissertation

Produce Low Aromatic Contents with Enhanced Cold Properties of Hydrotreated Renewable Diesel Using Pt/Alumina-Beta-Zeolite: Reaction Path Studied via Monoaromatic Model Compound

In this present work, Hydro-dearomatisation of toluene and hydro-isomerisation of n-hexadecane (n-C16) in ultralow sulphur diesel (ULSD) using Pt-Cl/H-Beta and Pt/H-Beta catalyst was investigated in a continuous down-flow trickle-bed reactor (DFTBR), and the physicochemical properties of products were studied. The catalytic effect on 40:60 wt% of H-beta-zeolite (H-β) and binder–aluminahydrochlorite extruded was characterized in scanning electron microscopy, nitrogen adsorption and coke testing. The study showed that 80 to 95 wt% of middle distillates recovered in ULSD on elevated temperature between 230 and 270 °C at 5 MPa. With a higher residence time of feed, the middle distillate recovered with 2.2 v/v% of aromatics and −32 °C of cloud point. In the model compound investigation of toluene and n-C16, it was observed that absorption of aromatic ring inhibits the rate of isomerisation; particularly it reduces the yield of branching and rearrangement of n-C16. Also, Cl-incorporated H-β extrudate enhanced the ring saturation and suppressed the reaction path in oligomerisation and cyclisation of paraffin. This methodology achieved asingle-stage upgrading technique involved in the delivery of commercial diesel in the market with low cloud point and aromatic content

Clinical spectrum of COVID-19 complications in young adults: combined analysis of the American Heart Association COVID-19 Cardiovascular Disease Registry and the Outcomes Registry for Cardiac Conditions in Athletes

Background While young adults 18–24 years old bear a significant proportion of COVID-19 diagnoses, the risk factors for hospitalisation and severe COVID-19 complications in this population are poorly understood.Objective The objective of this study was to identify risk factors for hospitalisation and other COVID-19 complications across the health spectrum of young adults diagnosed with COVID-19 infection.Study design Retrospective cohort study.Participants Young adults (aged 18–24) with confirmed COVID-19 infection from the American Heart Association (AHA) COVID-19 Cardiovascular Disease Registry of hospitalised patients and the Outcomes Registry for Cardiac Conditions in Athletes (ORCCA) study of collegiate athletes. The AHA registry included 636 young adults from 152 hospitals. The ORCCA registry consisted of 3653 competitive college athletes from 42 colleges and universities.Intervention None (exposure to COVID-19).Primary and secondary outcome measures Main outcomes included hospitalisation, death, major adverse cardiovascular events (MACE) and other severe clinical events.Results In comparison to the ORCCA registry, patients in the AHA registry were more likely to be female (59% vs 33%); had higher average body mass index (BMI) (32.4 vs 25.6); and had increased prevalence of diabetes (10% vs 0.4%), hypertension (7% vs 0.6%), chronic kidney disease (2% vs 0%) and asthma (14% vs 8%), all with p<0.01. There were eight (2%) deaths in the AHA hospitalised registry compared with zero in the ORCCA cohort. BMI was a statistically significant predictor of death in the hospitalised cohort (OR 1.05, 95% CI 1.00, 1.10). No significant predictors of MACE or other severe clinical events were identified.Conclusions The risk of cardiac events in young adults aged 18–24 diagnosed with COVID-19 infection is low. Patients who were hospitalised (AHA registry) were more likely to have pre-existing medical comorbidities and higher BMI than healthy collegiate athletes (ORCCA registry). Once hospitalised, elevated BMI is associated with increased mortality although other drivers of MACE and other severe clinical events remain unclear