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Investigation of drug aerosol size, delivery, and deposition in the mouth-throat airway using a soft mist inhaler (SMI): an experimental and numerical study
No full textRespiratory drug delivery has been a key area of research for several decades, driven by the high prevalence of pulmonary diseases and the superior treatment efficiency offered by this approach. However, despite its significant advantages, respiratory drug delivery faces major challenges, particularly low delivery efficiency and substantial drug deposition in undesired areas like the soft mist inhaler (SMI) mouthpiece, oral cavity, and throat wall. This study aimed to enhance the performance of inhalation therapy devices by leveraging insights and findings derived from experimental in-vitro and computational fluid dynamic (CFD) simulations.
This study examines the size distribution of drug aerosols and their deposition efficiency in the mouth-throat airway using an SMI. The SMI is known for its high drug delivery rates, ranging from 40% to 60%, and employs a unique atomization process through the Uniblock system to create fine particles that are ideal for lung deposition. To facilitate the research, the geometry of the mouth-throat region was constructed using three-dimensional (3D) printing technology with Ultimaker S3 and S5 printers, utilizing tough poly lactic acid (PLA) for precise and durable models. These printed geometries were then attached to a next-generation impactor (NGI) for experimental analysis. The NGI, which evaluates particle deposition and size distribution, was used to capture aerosolized particles at various stages according to their size. To quantify the deposition of the active pharmaceutical ingredient (API), high-performance liquid chromatography (HPLC) was employed at each stage and collection cup of the NGI, providing accurate measurements of drug deposition. Additionally, CFD simulations were conducted to model aerosol transport and deposition, offering valuable insights into airflow patterns, droplet size distribution, and the effects of geometric and physiological variations within the respiratory tract.
In the first part of the study, SMI performance was analyzed in two simplified mouth geometries: an idealized mouth (IM) and a standard mouth (SM). The effects of nozzle positions (along with the centerline), angles, and a fixed flow rate of 30 l/min were investigated to assess their impact on aerosol deposition and size distribution. The results indicated that SMI positioning and flow rate play a dominant role in determining deposition efficiency and size distribution, with higher flow rates reducing deposition within the mouth cavity. Recirculation regions and backward flows were identified as key contributors to increased particle residence time and deposition on mouth walls. Moving the SMI nozzle forward enhanced particle velocity at the outlet and reduced deposition, particularly in the SM geometry. These findings offer a foundation for developing innovative add-on devices, such as sensors or smart mouthpieces, to guide patients—especially children and the elderly—in optimizing inhalation techniques and improving drug delivery. [...
Enantioselective cross-coupling of monosubstituted ferrocenes in chiral ionic liquids
Get PDFPlanarly chiral ferrocenes have applications in pharmaceuticals, agrochemicals, and biomedical research for their use as ligands or catalysts in asymmetric synthesis. Previous methods of enantioselective synthesis of planar-chiral ferrocenes involve directed ortho-metalation with either a pre-installed centrally chiral group or chiral resolution. These methods use sensitive organometallic reagents, have low atom economy, and require additional steps to remove the chiral auxiliary or perform chiral resolution. Asymmetric cross-coupling is an enticing alternative, although enantioselective C-H bond activation poses a challenge. N-heterocyclic carbenes including imidazoliums can complex to palladium catalysts to act as a chiral ligand and strong σ donor and have previously been used to achieve C-H activation in arylations of benzaldehydes. This research aimed to achieve enantioselective arylation of ferrocenes, using a catalytic system comprising Pd(OAc)2, imidazolium salts and Cs2CO3 to achieve enantioselective catalysis, enabling asymmetric cross-coupling of aryl halides to monosubstituted ferrocenes, which yielded trace amounts of product. The addition of p-benzoquinone and Cu(OAc)2- acting as oxidants- expands the scope of the reaction to facilitate asymmetric cross-coupling of monosubstituted ferrocenes with aryl boronic acids. Additionally, a homocoupling reaction between aryl bromides with 65% yield was developed, which could also offer access to axially chiral biphenyl compounds. The enantiomerically pure compounds created using these techniques have applications in many areas of organic, bio and medicinal chemistry, including drug design, ligand synthesis for asymmetric catalysis and polymer chemistry used in research, medicine, and industry
Improving urban mobility for people with visual loss at floating bus stops in Canada
Get PDFAt present time, technological advancements and emphasis on inclusive urban planning are a
priority for transportation professionals to enhance urban mobility for road users, especially for
people with vision loss (PWVL). Among the various modes of transportation available, cycling has
emerged as an eco-friendly and efficient means of commuting. This mode of transportation also
comes as a major challenge to PWVL in an already complex urban environment since cyclists
cannot be detected by sound by this special population group.
This is particularly concerning at floating bus stops since buses do not pull up to the curb to load
and unload. Instead, floating bus stops are placed in the center of a road on a raised island, often
requiring transit riders to cross a cycling lane to access it. For PWVL, this is not only frightening
but also extremely dangerous. These unique transit hubs, while serving as vital transportation
nodes, present distinct navigational hurdles for PWVL since they often lack the familiar tactile
cues and infrastructure that assist in safe and independent navigation.
This research study will consider a comprehensive literature review of the accessible features
available for PWVL at these locations or similar as well as developing a system that will warn
PWVL of upcoming cyclists at these bus stops. This system will investigate the intersection of urban
mobility, technology, and accessibility with a particular focus on providing support to this group
of road users when navigating the intricate landscape of floating bus stops.
The results of the comprehensive literature review and preliminary conceptual approaches for this
system will be considered and included. Finally, understanding the multifaceted challenges faced
by PWVL when navigating urban environments and accessing public transportation is of
paramount importance since this will guide the process of determining the best possible solutions
to the issues
Assessing remote sensing estimations for burn area and tree mortality
Get PDFRemote sensing tools will increase the ability of land managers to visually
sample large areas more feasibly. This increase in applications of remote
sensing such as UAV aerial LiDAR may require an assessment of algorithm
accuracy while utilizing LiDAR data versus ground collected data to ensure
these applications are appropriate. One such application included within this
study is the detection of trees utilizing the LidR package which allows a cost-
effective and quick survey estimating trees contained, and providing their
estimated heights. The aim of this paper is to compare these detection results to
a traditional ground tree stocking survey, exploring the viability of applying tree
detection algorithms on post-burn forestry blocks to assess the surviving trees
allowing an indication of future stocking allowing the forest manager to create a
more accurate re-planting schedule. The results derived from this assessment
deviated significantly from ground surveys with the aerial analysis providing an
estimate of 2.20 WSP/ha and the ground survey estimating 70.18 WSP/ha (Well
spaced stems per hectare) within block 525_19C. Although stocking results
were inconclusive the analysis resulted in several useful outputs such as a
combination of orthomosaic imagery alongside the tree detection points. These outputs resulted in an effective visual aid allowing a more detailed visualization
of the spatial extent severe burns included within the forested blocks
Development of photobioreactors and approach for large-scale production of marine algae Chrysotila and Nannochloropsis in inland environment
Get PDFDue to energy, environment, and food problems, research on microalgae is increasingly
gaining attention. Microalgae can utilize photosynthesis to synthesize and accumulate
various valuable bioproducts such as lipids, proteins, polysaccharides, pigments, and can
also absorb and fix carbon dioxide. Therefore, efficiently, and cost-effectively cultivating
specific algae species has become a crucial goal. However, various challenges hinder the
development of algae during cultivation. This study focuses on the indoor and outdoor
cultivation of two marine microalgae, Chrysotila (Pleurochrysis) dentata and
Nannochloropsis oceanica.
For the cultivation of Chrysotila (Pleurochrysis) dentata, optimal indoor cultivation
conditions were determined with a light cycle of 18 hours light / 6 hours dark, pH of 8.5,
and salt concentration of 2.5 %. When Chrysotila (Pleurochrysis) dentata formed a
symbiotic system with the bacterium Nitratireductor aquibiodomus, a ratio of 8:2 (algae to
bacteria) resulted in optimal accumulation of dry weight, chlorophyll α, and calcium
carbonate, while ratios 6:4 was more suitable for lipid accumulation. In the experiment on
the impact of microplastics polyethylene terephthalate (PET) on Chrysotila (Pleurochrysis)
dentata, it was observed that low concentrations of plastic (5-15 mg/L) promoted algae
growth. However, high concentrations of microplastics (20-50 mg/L) slowed algal growth. [...
Evaluating feller buncher performance in interior British Columbia
Get PDFThis thesis examines the performance of harvesting equipment in British Columbia's forestry sector. The study examines two forest stands under CANFOR Ltd. in Prince George, British Columbia. It uses data from modern monitoring technology, FPTrak, to collect real-time data on two feller-bunchers, including their working and idle time. The primary goal is to collect data on the performance characteristics of these two feller-bunchers and determine whether there is variability in machine productivity under similar terrain conditions. The research also aims to identify factors that affect operational efficiency, reduce environmental consequences, and promote sustainability. It also seeks to analyze the productivity and utilization of the harvesting equipment and the amount they harvested. The study helps maximize efficiency, reduce environmental effects, and optimize harvesting machinery in the forestry industry. The results shed light on the variables impacting machine productivity, the effects of technology improvements, and the significance of sustainable forest management techniques. They also offer insightful information about the performance of feller-bunchers in British Columbia
Impacts of projected future temperature rise on the hydrology of Neebing River, Ontario
Get PDFThe projected future temperature rise is likely to change the Neebing River's hydrology
over the following decades. The changing hydrological patterns are expected to cause increased
hydrological extremes in the City of Thunder Bay, Ontario. To safeguard this city from future
climatic extremes, it is necessary to understand the Neebing River's hydrological response to
anticipated future temperature rise and consider efficient prevention and long-term adaptation
techniques. This study investigates the potential impacts of projected future temperature rise on
the hydrology of the Neebing River Watershed and identifies potential mitigation and adaptation
strategies. The Soil and Water Assessment Tool (SWAT) has been used to simulate the future
streamflow for the period of 2041-2060 (near future), 2061-2080 (intermediate future), and 2081-
2100 (distant future). The future air temperature and precipitation projections have been derived
from three Global Climate Models (CanESM5, GFDL-ESM4, and INM-CM4-8) under medium
(SSP2-4.5) and high (SSP5-8.5) emission scenarios. The SWAT model results reveal that
compared to the baseline period of 2004-2023, the streamflow will increase significantly during
the three future periods. There will be an increase in the winter, spring, and fall streamflow while
a decrease in the summer streamflow. The results also suggest an increased intensity of future
streamflow events. The findings of this study are expected to guide policy decisions intended to
minimize damages from the unavoidable impacts of the projected future temperature rise. This
study will also contribute to our understanding of the climate response of rivers in the Lake
Superior basin and Northern Ontario in general
Indirect minimization of common-mode voltage with finite control-set model predictive control in a five-level inverter
Get PDFMultilevel inverters (MLIs) are counted as the crucial part of the electric drive systems
(EDSs) primarily due to their ability to handle higher operating powers and voltages, to
provide high-quality output waveform, and to reduce dv/dt. Nevertheless, MLIs require a
complex control system to handle multiple control objectives such as load currents, floating
capacitors (FCs) voltage, current tracking errors, and common-mode voltage (CMV) minimization. Among them, the load current and FC voltage objectives are associated with the
basic operation of the MLI, whereas the CMV minimization is associated with the safety
and reliability of the MLI-fed EDSs. Hence, the CMV minimization becomes obligatory to
ensure the safety of the system.
To achieve multiple objectives of MLIs, finite control-set model predictive control (FCSMPC) methods became promising solutions due to the following features: (i) ease of implementation, (ii) intuitive philosophy, (iii) fast transient response, (iv) ability to handle
multiple objectives with a single cost function, (v) easy to compensate control delay, and
(vi) flexible to include system constraints and nonlinearities. However, FCS-MPC methods
use a cost function with weighting factor to directly minimize the CMV of MLIs. The improper selection of weighting factors directly affects the current harmonic distortion of MLIs.
They also need higher execution time to implement in real-time control platforms.
To address the challenges associated with the conventional FCS-MPC methods, a new
per-phase FCS-MPC philosophy is proposed in this thesis. The proposed philosophy minimizes the CMV without using a cost function, thereby eliminating the need of weighting
factors and their impact on current harmonic distortion. Also, the proposed FCS-MPC
is designed to achieve the control objectives of each phase by using an independent cost
function, resulting in a shorter execution time. The proposed philosophy is applied to a
five-level inverter (FLI). The continuous-time and discrete-time models of FLI are developed
to implement the proposed FCS-MPC. Finally, the steady-state and transient performances
are verified on dSPACE-DS1103 controlled FLI laboratory prototype. Also, a comparative
analysis of the proposed and conventional FCS-MPC is presented
Understanding drivers and correlates of fish productivity: Finding optimal indicators in freshwater fishes
Get PDFCanadian freshwater commercial and recreational fisheries contribute $8.8 billion
in revenue to the economy annually and are a significant subsistence food source for
Indigenous communities. Fish production is recognized as the best indicator of fish
population fitness and for assessing productive capacity at both the population and
community levels and is legislatively required by the Canadian federal government to
prevent, mitigate and/or monitor impacts of development in the Fisheries Act. However,
empirical tests of correlates and drivers of fish productivity are lacking due to the
extensive effort and monetary expense required to calculate estimates of production.
Using approximately 20-years of data from disturbed and undisturbed freshwater fish
populations and the environments that support them at the IISD-Experimental Lakes Area
(ELA) this dissertation explored spatiotemporal correlates and drivers of freshwater fish
production. Here, I (i) proposed modifications to current estimation methodologies
through the use of von Bertalanffy growth models to allow for estimates of negative
production, (ii) identified key fine-scale mechanisms of both population- and communitylevel fish production temporally, as well as population-level production over regional
scales, and (iii) based on these analyses, provide recommendations for variables that can
be used as surrogates of fish production. I show that physiochemical and limnological
factors that influence habitat availability (i.e., total phosphorus, dissolved organic carbon)
dictate lower food web dynamics (i.e., prey quantity and access to prey) and resulting life
history strategies (i.e., mean weight, mean length, abundance, and body condition), to
ultimately shape fish productivity, demonstrating that fish production is primarily driven
by factors that shape individual- and population-level bioenergetics