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Factors that impact opioid agonist therapy in Northern and Rural Ontario
Get PDFOpioid agonist therapy is the gold standard of care for opioid dependence.
However, the efficacy of treatment may be hindered by concurrent drug use, including
cocaine and benzodiazepines. This thesis examines the impact of concurrent drug use on
treatment retention, and whether it is differentially impacted by geographic region. We
conducted a retrospective cohort study using electronic medical records from 58 opioid
agonist therapy clinics in Ontario. One-year treatment retention was the primary outcome
of interest. Both baseline cocaine and benzodiazepine users experienced decreased
retention rates than non-users. Patients who used concurrent drugs at higher frequencies
experienced decreased retention rates compared to those who used less often. Northern
and urban patients were more likely to be baseline cocaine users, and Southern urban
patients were more likely to be benzodiazepine users. Both baseline and continued
concurrent drug use is predictive of treatment drop out in Northern and Southern patients
The secondary structure of the 5’-end of the STb mRNA affects its secretion efficiency
No full textThe majority of secreted proteins in E. coli are targeted to and translocated across the
cytoplasmic membrane through a signal sequence within the N-terminus of the protein. The major
membrane complex facilitating this process is the general secretory or Sec-dependent membrane
complex, also known as T2SS secretion. Research with proteins that are processed for export
through a different pathway, called the T3SS secretion system, has recently challenged this widely
accepted hypothesis. This research has provided evidence that the T3SS secretion system
substrates may use mRNA sequences as a secondary means of protein targeting in addition to the
N-terminus of the synthesized protein. The main objective of this study was to test whether or not
the mRNA of the T2SS secretion system substrates may have structural information sufficient for
efficient targeting of the protein for secretion. A well-studied substrate of the T2SS secretion
system in E. coli is the heat-stable enterotoxin B (STb). The STb gene was cloned and a number
of mutations were introduced within the 5' end of its mRNA to look at the effect of such mutations
on protein secretion. The results showed that mutations that lead to changes in the AT/GC ratio
within this 5’ region of the gene, while conserving the amino acid sequence of that region, affected
toxin secretion. Bioinformatic analysis showed that these mutations affected the secondary
structure of the 5' end of the mRNA and indicated that significant changes can be produced in the
secondary structure of the mRNA when the AT/GC ratio is modified. This data shows that
alterations in the secondary structure of the 5' end of the mRNA, without changes in the amino
acid sequence of the N-terminus of the protein, can affect the efficiency with which the toxin is
secreted and hints to a possible role for the mRNA in targeting proteins for export across the
cytoplasmic membrane
Cloning and studying the role of mycobacterium tuberculosis multicopper oxidase in inhibiting the respiratory burst.
No full textMycobacterium tuberculosis is the etiological agent of the pulmonary disease Tuberculosis. It affects more than one-third of the world’s population. During bacterial infections, macrophages and other phagocytic cells of the immune system target and neutralize the causative agent. Following phagocytic uptake of bacteria by the macrophages, the phagolysosomal compartment produces reactive oxygen species (ROS) through the so-called respiratory burst to control the infection. Recent work by several groups indicates that pathogenic M. tuberculosis can survive phagocytic uptake by macrophages through inhibition of the respiratory burst. I have cloned and expressed Rv0846c, a protein known to be a membrane-associated multi-copper oxidase from M. tuberculosis (MmcO). I hypothesised that MmcO suppresses the production of ROS and may thus contribute to the survival of the pathogen during phagocytosis. Purified MmcO displayed a significant activity against the model substrate ABTS. Various amounts of active MmcO were tested against the ROS production in THP-1 monocyte cell line. Streptolysin-Opermeabilized THP-1 cells that were exposed to 500 ng of the purified MmcO protein displayed asignificant reduction in the level of induced ROS by phorbol 12-myristate 13-acetate (PMA). This study indicates that the MmcO has a potential role as a virulence factor for M. tuberculosis
The effect of dielectric permittivity on the fields radiated from a radio-frequency electric dipole in a homogeneous whole space
No full textThis paper is © 2019 Society of Exploration Geophysicists. The posting is available free of charge and its use is subject to the SEG terms and conditions: https://seg.org/Terms-of-UseThe radio imaging method (RIM) is an electromagnetic cross-borehole method with applications in mineral exploration, as well as in the coal industry, where it is used across mine drives. Attenuation of the signal from conductive regions may indicate areas of mineralization, and these conductive effects in general dominate the response. In an effort to better understand the effect of a material’s dielectric permittivity on the response of the RIM, we have developed a simple program to model an electric dipole in a homogeneous whole space. When increasing the dielectric permittivity, the amplitude peak broadened and increased, whereas the phase peak sharpened and shifted negatively. To showcase the effect of dielectric permittivity on RIM data, data recorded from two transmitter positions in a moderately homogeneous zone in the Sudbury Basin were curve fit, and we concluded that despite the stronger effect that conductivity has on the signal, RIM is still sensitive to dielectric permittivity, and appropriate values must be used when developing conductivity tomograms. In addition, we found that for the given situation and frequencies used, an increase in either the conductivity or dielectric permittivity could be accounted for by a decrease of approximately the same factor in the other variable. However, the low-conductivity, high-permittivity case seemed to fit the shape of the amplitude and phase curves better. For the sulfide impregnated crystalline rocks at our field site, relative dielectric constants of 26.4 and 31 at 1250 and 625 kHz, respectively, were inferred.KGHM International, Sudbury Integrated Nickel Operations A Glencore Company, Vale Limited, Wallbridge Mining Company, the Centre for Excellence in Mining Innovation (CEMI), the Mineral Exploration Re- search Centre (MERC), and NSER
Numerical modeling of unstable rock failure.
No full textRockburst is an unstable and violent rock failure and it is a hazardous problem in deep underground mines and civil tunnels; it imposes a great danger to safety of workers and investment. Many factors that influence rockburst damage have been identified. In many rockburst case histories, the presence of geological structures such as faults, shear zones, joints, and dykes has been observed near excavation boundaries but their role in rockburst occurrence is still not fully understood. A good understanding of the role of geological structures on rockburst damage is important to anticipate and control rockbursts and constitutes the focus of this thesis.
In this research an explicit finite element tool (Abaqus-Explicit) is employed to study unstable rock failure and rockburst processes. First, uniaxial compression tests were simulated to confirm the suitability of the adopted numerical tool for simulating unstable rock failures. Two indicators namely Loading System Reaction Intensity (LSRI) and the maximum unit kinetic energy (KEmax) were proposed to distinguish between stable and unstable failures in laboratory testing conditions. Unstable rock failures under polyaxial unloading conditions were also simulated. The influences of loading system stiffness, specimen‘s height to width ratio, and intermediate principal stress on rock failure were investigated.
Next, material heterogeneity (in terms of strength and deformability) was introduced into the models using Python scripting to enhance the efficiency of Abaqus for modeling geomaterials. Numerical simulation results showed that heterogeneous models resulted in more realistic failure modes than homogeneous models. The effect of material heterogeneity on rock failure intensity in unconfined and confined compression tests was investigated. It was observed that when two materials have the same peak strength, the heterogeneous model had more released energy than the homogeneous model due to differences in the failure mode. The tensile splitting failure mode of the heterogeneous model released more energy than the shear failure mode of the homogeneous model.
Then, the role of geological weak planes on rockburst occurrence and damage near the boundary of tunnels was studied using 2D models. Initially, a tunnel without any adjacent weak plane was modeled. Then a fault with different lengths, inclinations, and distances to the tunnel was added to the models and its effect on rock failure was simulated. The velocity and the released kinetic energy of failed rocks, the failure zone around the tunnel, and the deformed mesh were studied to identify stable and unstable rock failures. The simulation results showed that the presence of a fault near a tunnel could induce rockburst if the fault is positioned and oriented in such a way that it promotes high stress and low local loading system stiffness.
Finally, a rockburst that occurred in the Jinping II drainage tunnel in China with an observed nearby fault was simulated. The modeling results captured the field observation of rockburst damage and confirmed that the presence of weak planes in the vicinity of deep tunnels is a necessary condition for the occurrence of rockburst. The finding from this research constitutes a better understanding of unstable rock failures in both laboratory and in situ. The insights gained from this research can be useful for rockburst anticipation and control during mining and tunneling in highly stressed grounds
In pursuit of societal harmony : reviewing the experiences and approaches in officially monolingual and officially multilingual countries
No full textNanocomposites of carbon nanosphere and graphene oxide with iron oxide as high-performance adsorbents for arsenic removal
No full textArsenic is a widely distributed element in the Earth’s crust with an average
terrestrial concentration of about 5 g ton-1
. Arsenic is a persistent, bio-accumulative, toxic
element. The United States Environmental Protection Agency (EPA) has implemented the
discharge criterion of 10 µg L
-1
for arsenic as the maximum acceptable level for ground
water. During the past decades, several techniques have been developed for the removal
of arsenic from the wastewater, including chemical precipitation, adsorption and ion
exchange, membrane and biological removal processes, and so on. Because of the good
arsenic removal efficiency and the low cost, adsorption is a more popular method. In this
thesis research, two ranges of iron oxide nanocomposite adsorbents have been developed
and studied for their performance properties towards arsenic removal.
Novel iron oxide encapsulated carbon nanospheres (FeOx-CNS) with excellent
arsenic adsorption performance has been successfully synthesized. CO2 activated carbon
nanospheres material (A-CNS) with high surface area (2271 m²g
-1
) and high pore volume
(5.18 cm³g
-1
) was selected as the porous matrix. After surface oxidation by ammonium
persulfate (APS), iron oxide was loaded into the carbon nanospheres as the effective
arsenic adsorbent. Transmission electron microscopy (TEM) and Braunauer–Emmett–
Teller (BET) results indicate that iron oxide nanoparticles (7-60 wt%) are well-dispersed
within the mesopores. In particular, FeOx-CNS-13 composite shows most optimum performance properties, with high arsenic adsorption capacities achieved for both As(III)
(416 mg g−1
) and As(V) (201 mg g−1
).
Another range of amorphous iron oxide-graphene oxide (FeOx-GO)
nanocomposites having different graphene oxide (GO) content (36-80 wt%) was prepared
by coprecipitation of ferrous sulfate heptahydrate and ferric sulfate hydrate on GO sheets.
The composites have been thoroughly characterized and investigated for their
performance towards arsenic removal. The optimum composite, FeOx-GO-80 having the
highest iron oxide content of 80 wt% shows excellent arsenic adsorption capacities for
both As(III) (147 mg g−1
) and As(V) (113 mg g−1
), which are highest among iron oxideGO
composites reported to date for arsenic removal. The high performance along with
low cost and convenience in synthesis makes this range of amorphous iron oxide-GO
nanocomposites promising for applications
Peer victimization in Northern Ontario: the search for protective factors to combat reported health concerns
No full textThis master’s thesis study looked to expand on the current body of literature regarding
the potential role of social support for individuals who have been exposed to bullying. More
specifically, the study examined how connected social support is to the concept of resilience, and
compared levels of social support, levels of resilience, and health concerns between victims of
bullying and those not involved in incidents of victimization. Questionnaires were completed by
112 students in grades seven and eight from two school boards in Northern Ontario. Participants
were asked to complete a questionnaire booklet consisting of four separate questionnaires. The
Behaviour Assessment System for Children, Second Edition, Child and Adolescent Social
Support Scale, Child and Youth Resilience Measure, and a modified version of the Revised
Olweus Bullying Victim Questionnaire were used in this study. The questionnaires were
completed after a brief presentation on the definition of bullying, forms of bullying, and how
students may be involved. Analyses showed that overall social support did not act as a buffer for
total health concerns based on one’s bully status (victim versus not-involved). Social support and
resilience were found to be moderately and positively correlated to one another based on selfreports.
Lastly, similar to previous literature, victims had higher mean scores for health concerns,
and lower mean scores for social support and resilience compared to the non-victim group.
Therefore, all students may benefit from perceiving strong social support systems, not just
victims of bullying. Prevention and intervention programs should include training for school
personnel to expand support networks that are currently perceived as lacking by victims of
bullying, especially with the results of this study indicating results surrounding negative health
outcomes, lower levels of perceived social support and low levels of resilience for victims
The use of mitochondrial DNA for the identification of fish in the early stages of development from the eastern shores of Lake Huron, Ontario, Canada
No full textIchthyoplankton specimens are notoriously difficult to identify using morphology. DNA
barcoding and real-time PCR utilize DNA to identify specimens, rather than morphology.
However, no study has yet compared morphological identifications with DNA-based
identification for Canadian freshwater fishes. Here, we both compare DNA barcoding with
morphological identification of ichthyoplankton and design a multiplex TaqMan real-time PCR
assay for the rapid and cost-effective identification of 3 important species in Lake Huron, lake
whitefish (Coregonus clupeaformis), deepwater sculpin (Myoxocephalus thompsonii) and round
whitefish (Prosopium cylindraceum). Unlike morphological identification, DNA barcoding was
able to resolve specimens from the Catostomus genus and Cyprinidae family to the species.
Contrarily, DNA barcoding was unable to differentiate some members of the Coregonus genus,
whereas morphology identified these specimens to the species. Real-time PCR was able to
accurately identify the target species 100% of the time and was the most cost-effective method
Journey to wellness: Identifying culturally relevant supportive services for First Nations peoples in Northeastern Ontario during their cancer journey
No full textThis thesis is intended to identify culturally relevant supportive services for First Nations in
Northeastern Ontario, as perceived by service providers, in order to improve access to cancer
care services and the follow-through of treatment at the time of diagnosis and during treatment.
The author interviewed thirteen front line health care providers who provide direct services to
First Nations communities. The participants within the research study discussed the importance
of relationships First Nations peoples have with family members and their community as well as
to the land and water. The need for supportive services that incorporate family and community,
as well as land and water based healing practices are integral in ensuring the psychosocial needs
of First Nations cancer patients are being addressed in a culturally relevant and safe fashion and
that these services are significant for the patient, family, and community. The results of this
research will be useful in broadening the understanding of the needs of service providers in First
Nations communities who are working with First Nations patients during their cancer journey