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Design, Simulation, and Techno-Economic Evaluation of a Novel Process for Ethanol Recovery from Fermentation Broths
No full textAddressing rising energy needs, particularly in industry, transportation, and heating, while simultaneously decreasing the rate of greenhouse gas emissions, is a critical challenge facing society nowadays. Liquid biofuels produced from renewable sources, such as ethanol, have received increased research attention because they show long-term viability potential and fit the current transportation infrastructure.
Ethanol is produced by the anaerobic fermentation of sugars obtained from renewable biomass. Conventionally, ethanol is recovered from the aqueous fermentation broth using at least two distillation steps combined with a dehydration step. However, this configuration requires large amounts of energy and is particularly inefficient, mainly due to the low ethanol concentrations achieved in the fermentation broth, and the formation of an ethanol-water azeotrope.
In this thesis, a new extraction-pervaporation system was proposed and investigated for use in ethanol recovery. In this process, ethanol is extracted from the fermentation broth using organic solvents and recovered from this mixture by pervaporation. It was envisioned that this new process configuration would lead to improved energy efficiency and economics for the ethanol production process.
The proposed process was investigated using numerical and experimental techniques. New polymeric membranes were developed and were shown to be effective in separating ethanol/2-ethylhexanol and ethanol/pentanol mixtures. The permeates were obtained at similar or higher concentration than that achievable in enriching distillation columns. The pervaporation mass transfer process was modelled accounting for the effect of concentration polarization and for concentration-dependent diffusion in the membrane layer, and results showed that, under the conditions studied, the mass transfer resistance in the membrane controls the pervaporation process. It was also shown that higher temperatures and feed concentrations result in higher fluxes through the membrane.
A pervaporation numerical model incorporating a membrane permeability model based on the results achieved in previous sections was developed. Ethanol extraction from the broth was also modelled, as well as the fermentation process. A techno-economic analysis was carried out and results indicated that, although the current economic performance is lacking, the extraction-pervaporation process is more energetically efficient than the distillation process, achieving similar ethanol concentrations while requiring less than half of the amount of energy input
AUTOMATED FABRICATION OF A COLLAGEN FIBER SCAFFOLD WITH TUNABLE STRUCTURE FOR CORNEA TISSUE ENGINEERING
No full textSeveral attempts have already been made to create a synthetic cornea, as this could solve the problems of graft availability and rejection for those in need of a corneal transplant. To address this need, a device was designed which has the capability of semi-autonomously creating collagen fibers. This device is capable of making a scaffold with a layer of collagen fibers structured like the corneal stroma, and a layer of structured like the corneal Bowman’s membrane. Microscopic visible light transmission studies suggest that these scaffolds transmit at least 98% of visible light. By varying the fabrication parameters, a hydrated scaffold with a tensile strength of 3.24 MPa and a Young’s modulus of 40.10 MPa was achieved. This evaluation suggests that this device can create scaffolds with mechanical properties closer to those of the native human cornea, compared to the collagen hydrogels previously used as corneal implants
EFFECT OF PYROLIGNEOUS ACID ON GRAPE PRODUCTION AND DISEASE MANAGEMENT
No full textPyroligneous acid (PA), a by-product of biomass pyrolysis, has emerged as a promising biostimulant in agricul-ture. This thesis investigated the biostimulatory effect of PA on grape (Vitis vinifera cv. KWAD7-1) production, juice, and wine quality, and its antifungal properties. The first study focused on the effects of PA (0%, 2%, 4%, 8%, and 12%) on metabolite accumulation in grape wine. Using Nuclear Magnetic Resonance analysis, 52 me-tabolites across seven compound groups were identified and quantified. The 12% PA treatment resulted in the highest °Brix content of the grape juice and significantly (p<0.05) altered the concentrations of organic acids, amino acids, and sugars of the grape wine. The second study examined the impact of varying PA concentrations (0%, 4%, 8%, and 12%) and application frequencies (14-, 21-, and 28-day intervals) on grape growth, yield, and chemical composition. The results showed that 4% PA applied at 21-day interval significantly (p<0.05) improved grape vine growth, and yield and juice quality parameters. The treatment also enhanced the accumulation of ben-eficial compounds such as carotenoids, phenolics, and flavonoids in grape leaves, pomace, and juice. The third study investigated the efficacy of PA on Botrytis cinerea disease management in grapes. Various concentrations of PA were evaluated for their ability to suppress B. cinerea growth and infection in vivo. The results demonstrated that PA exhibited significant (p<0.05) antifungal activity against B. cinerea, with higher concentrations showing greater disease suppression. These findings demonstrate that PA application can be an effective strategy to enhance grape wine quality, productivity, and manage fungal diseases. The research provides valuable insights into the use of PA as a sustainable tool for modulating grape and wine characteristics to meet consumer preferences and po-tentially improve nutritional value, while also offering an environmentally friendly approach to disease manage-ment in viticulture
EXAMINING THE ASSOCIATION BETWEEN BREAST CANCER TREATMENTS AND SELF-REPORTED SEXUAL DYSFUNCTION IN CANADIAN WOMEN: A POPULATION-BASED CROSS-SECTIONAL STUDY
No full textThis study was a cross-sectional population-based study among female breast cancer survivors.Background
The prevalence of female breast cancer survivors in Canada has increased from 1.8% to 2.1% (2007-2021). Sexual dysfunction is a common long-term side effects of breast cancer treatments.
Objective
To estimate the prevalence of self-reported sexual dysfunction among breast cancer survivors in Canada and examine the association between of single and combined treatment modalities and sexual dysfunction.
Methodology
This cross-sectional study utilized data from 3772 participants who participated in the 2016 Experiences of Cancer Patients. The outcome was sexual dysfunction. The exposures chemotherapy, radiotherapy, and endocrine therapy. Multivariable logistic regression models were used to evaluate associations.
Results
Sexual dysfunction was most prevalent among survivors treated with chemotherapy (48.3%). Chemotherapy, endocrine therapy, radiotherapy, and combined modalities were associated with sexual dysfunction, with the highest odds observed among those receiving all three treatments.
Conclusion
Sexual dysfunction is common among Canadian breast cancer survivors and is associated with all treatment modalities
A Long Term Analysis of Internal Migration and Climate Change as Drivers of Urban Growth and Slum-Like Housing in Kenya
No full textOver 1.1 billion urban residents live in unacceptable conditions, lacking access to clean water, durable housing, and adequate sanitation. However, the drivers of this growing problem have been understudied due to a lack of granular data tracking the populations living in such conditions and their drivers. This dissertation fills these gaps by developing a dataset using four censuses for Kenya that tracks urban populations living in slum-like conditions and the drivers of urban population growth across urban centres from 1989 to 2019. This dissertation shows that the contribution of natural increase to urban population growth is larger than net in-migration in many urban centres and that the growth in urban centre populations living in slum-like housing is more strongly associated with natural increase. This dissertation also shows that climate change is a significant driver of net in-migration towards urban centres, potentially deepening the deficit of adequate urban housing in Kenya
PostMom: An AI-Powered Culturally Tailored Persuasive App for Postnatal Support for Underserved Nigerian Mothers
No full textThe World Health Organization (WHO) recommends that pregnancy, childbirth, and the postnatal period should be positive experiences for all women, yet many underserved women in countries including Nigeria still lack adequate postnatal support. Limited access to postpartum care, cultural barriers, and inadequate health communication continue to hinder positive postnatal outcomes for Nigerian mothers. Although artificial intelligence (AI)-powered mobile health (mHealth) applications exist for maternal health, culturally appropriate interventions that integrate persuasive strategies for postnatal education and support remain limited, especially in low-resource contexts. This thesis presents PostMom, a persuasive mHealth technology that integrates AI techniques, including natural language processing (NLP), to deliver culturally appropriate postnatal health education and support for underserved Nigerian mothers. This work followed a three-phase, user-centered process. First, a review of 62 studies on AI in maternal health identified gaps in existing solutions and informed a set of persuasive strategies using the Persuasive System Design (PSD) model. Second, guided by these insights and consultations with four Nigerian medical doctors, a medium-fidelity prototype of PostMom was designed and evaluated through surveys and semi-structured interviews with 36 Nigerian mothers, whose feedback shaped design refinements. Third, a refined version of PostMom was developed and deployed in a one-week field study during which 70 mothers used the application for daily postnatal guidance and support. Results from validated usability and user experience assessments demonstrated good usability and positive user experience, while pre-post knowledge assessments showed that PostMom's persuasive features significantly improved participants' postnatal health knowledge (p < .001) and enhanced health information literacy. This thesis offers design recommendations for postnatal health applications, underscoring the importance of a human-in-the-loop design process. Overall, this work contributes to understanding the design and development of culturally tailored, AI-powered persuasive technologies for improving postnatal health knowledge, and enhancing postnatal care experiences for underserved populations
KAPOSI’S SARCOMA-ASSOCIATED HERPESVIRUS REMODELS THE NUCLEUS AND ENDOPLASMIC RETICULUM DURING INFECTION
No full textThe thesis describes new insights into how the nuclear membrane and endoplasmic reticulum are re-shaped during Kaposi's sarcoma-associated herpesvirus infection. Within three results chapters, the thesis describes how the viral protein K3 targets the mammalian protein PERK for degradation to control ER-stress. In the second results chapter, the same viral protein K3 is shown to target another viral protein called vGPCR for degradation. In the final chapter, a new mechanism for viral nuclear egress is documented.Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi’s sarcoma, primary effusion lymphoma, multicentric Castleman’s disease and KSHV-induced cytokine syndrome. KSHV follows a biphasic infectious cycle: upon infection it establishes latency with the genome maintained as an episome tethered to host chromatin, and cellular stress triggers expression of the replication and transcription activator RTA (ORF50) which initiates lytic replication, a program featuring heightened viral gene expression and genome replication. Lytic replication places a heavy burden on the endoplasmic reticulum (ER), the site of folding and modification of secreted and transmembrane proteins and activates the unfolded protein response (UPR). The UPR is coordinated by three ER-localized sensors, PERK, IRE1 and ATF6, which initiate complementary transcriptional programs that expand folding capacity and lipid synthesis, while PERK signaling attenuates cap-dependent translation and can trigger apoptosis if stress is unresolved. KSHV inhibits each arm of the UPR during lytic replication, but the viral factors and mechanisms responsible are incompletely understood. In this thesis I report that the early viral E3 ubiquitin ligase K3 directs K63-linked polyubiquitination of PERK, targeting PERK for lysosomal degradation and thereby terminating PERK signaling. ER stress enhanced K3-dependent PERK turnover, consistent with signal-dependent PERK degradation which converts PERK activation into PERK removal. I demonstrate that the viral G protein-coupled receptor vGPCR induces ER stress and potentiates K3-dependent PERK degradation, and that K3 reciprocally ubiquitinates vGPCR to promote its lysosomal clearance. Therefore, K3 regulates both a source of ER stress and the principal PERK-dependent response. Infection with a K3-deficient virus results in the dysregulated accumulation of viral proteins despite unchanged transcription, implicating K3 in post-transcriptional control of viral proteostasis. Subsequent ultrastructural and live-cell microscopy revealed extensive nuclear membrane remodeling during lytic replication in both WT and ∆K3 infections, pertaining to expansion of the Type-I nucleoplasmic reticulum. These invaginations serve as sites for primary envelopment and nuclear egress, and I document genetically and chemically labeled capsids traffic through these compartments into the cytosol. Together, these studies show that KSHV coordinates robust remodeling of ER and nuclear membranes to support productive infection, with K3 central to manage ER-stress and viral protein proteostasis
MAST CELL STING ACTIVATION IN INFECTION AND CANCER IMMUNITY
No full textMast cells (MCs) are long-lived, tissue-resident immune cells essential for host defense. The STING pathway, a key innate immune response to infection and cellular stress, promotes strong type I interferon (IFN) and pro-inflammatory responses. While the STING pathway holds therapeutic potential in cancer and infection, its role in MCs remains underexplored. Our study demonstrates that MCs trigger type I IFN and NF-κB responses upon STING activation. We show that MCs are susceptible to Shigella flexneri infection, leading to an upregulation of type I IFN and interferon-stimulated gene expression, partially dependent on STING. In a murine ovarian cancer model, MC deficiency led to longer survival, whereas reconstituted MC-deficient mice surprisingly showed improved survival. Treatment with a STING agonist increased survival, but overexpressing STING in MCs within tumors provided no additional benefit. These findings offer valuable insights into STING-mediated immunity in MCs and highlight potential avenues for future therapeutic exploration
Quantifying and Studying Electrolyte Pumping in Lithium-Ion Cells Using Rotational Inertia Measurements
No full textState-of-the-art cylindrical Li-ion cells can be susceptible to degradation in the form of accelerated inhomogeneous lithium plating on the negative electrode, which has recently been shown to be caused by an electrolyte motion-induced salt inhomogeneity in the electrolyte. Electrolyte motion is caused by the cyclic expansion and contraction of the electrode active materials at different states of charge, which displaces some of the electrolyte back and forth between the pores of the electrodes and the empty and inactive areas located at the ends of the cylindrical cell and in the core of the electrode winding. To study electrolyte motion, Rotational Inertia Measuring instruments have been developed, which are torsional oscillators that detect changes in the resonant frequency of a cylindrical cell as its mass distribution changes during cycling. Resonant frequency changes are used to calculate the amount of displaced electrolyte in relation to the state of charge of the cell. Rotational Inertia Measuring instruments are effective for studying electrolyte motion in a variety of cylindrical cell formats, with the goal of understanding and reducing the impact of electrolyte motion on cell degradation