30921 research outputs found
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Facilitating antimicrobial stewardship in the outpatient hemodialysis setting
Get PDFAntimicrobial stewardship (AMS) encourages appropriate antimicrobial use to improve outcomes. Initiatives include preventing infection and optimizing antimicrobial use (i.e., right drug, dose, and duration). Infections are associated with significant morbidity and mortality among patients receiving hemodialysis. Although this population would benefit from AMS, initiatives are limited. In response, three studies were conducted.
The first was a study of hemodialysis bloodstream isolates (n = 1024). Pathogen distributions and antimicrobial susceptibilities were used to evaluate empiric antimicrobial combinations. Most isolates (>70%) were gram-positive. Using cefazolin over vancomycin reduced gram-positive coverage by >30%. Gram-negative coverage varied by <1%, with no advantage for broader agents, e.g., meropenem. These findings assist in optimizing empiric antimicrobial selection for bloodstream infections (BSIs) in the hemodialysis setting.
The second was a study of hemodialysis catheter-related exit-site infections (ESIs, n = 113) and BSIs (n = 64). The impact of new infection prevention measures on infection rates and risk factors for infection were evaluated. ESIs dropped by 60% with new measures, then increased slightly over time. BSIs declined by 85% over time, which was associated with new measures and reduced temporary catheter use. ESIs preceded one-third of BSIs. These findings highlight the necessity for ongoing surveillance, reinforcement of prevention measures, and strategies to address ESIs to reduce BSI risk.
The third was a pharmacokinetic study of cefazolin (n = 20) and ceftazidime (n = 18) in patients receiving hemodialysis. The pharmacokinetics, pharmacodynamics, and toxicodynamics were characterized and used to evaluate current dosing practices. For both drugs, the protein binding and volume of distributions were similar to other populations, while the elimination half-lives were >15-fold longer compared to patients with normal kidney function. In the cefazolin cohort, there was greater interindividual variation in half-life attributed to residual kidney function. The analysis identified limitations in using a one-dose-fits-all approach. It highlighted the importance of considering residual kidney function, body weight, the interdialytic period, and pathogen susceptibility to optimize dosing. These findings can be used to develop adaptive dosing approaches that improve the treatment of infections in this high-risk population.
Given the lack of data, this work represents significant progress in facilitating AMS in the hemodialysis setting.May 202
Lactating parents attending Winnipeg Breastfeeding Centre: a descriptive study
Get PDFIntroduction
The World Health Organization recommends exclusive breastfeeding for the first six months of life and continuation of breastfeeding for at least two years. In Canada, 91.0% of parents initiate breastfeeding, yet only 38.0% continue six-month exclusive breastfeeding. The Winnipeg Breastfeeding Centre (WBC) is the only clinic in Manitoba providing physician-level lactation care. My project aimed to describe the WBC patients’ demographic characteristics, breastfeeding difficulties, diagnoses, and treatments.
Methods
This retrospective study describes the WBC population from March 2018 – December 2023 using the clinic’s electronic medical records, following the exclusion of follow-up appointments. The data included: intake questionnaire (n=3,230), referral data (n=6,778), and a random sample of the visit notes (n=79). To facilitate descriptive analysis, I manually extracted and coded the free text data from visit notes, which involved converting the "assessment and plan" sections into discrete variables reflecting diagnoses and interventions (i.e. education and supportive psychotherapy).
Results
WBC received referrals from physicians (79.7%), nurse practitioners (1.1%), and midwives (0.1%). The mean infant and maternal age were 8.7 weeks (SD ± 11.4, 95% range 1.0 - 37.4) and 34.8 years (SD ± 4.7; 95% range 25.0 - 44.0), respectively, with 57.9% primiparity and 65.7% vaginal delivery. The WBC patient population mostly resided in Winnipeg (75.0%), Southern Health (15.0%), and Interlake-Eastern (8.1%) regional health authorities. Fort Garry, River East, and Saint Boniface were the most common locations in Winnipeg (34.4 % combined). Referrals to the WBC rose 2.1-fold after March 2020 (COVID-19 pandemic onset) compared to pre-pandemic and remained elevated post-restrictions (May 2023), reflecting both clinic growth over the years and COVID-19 pandemic conditions.
At the time of referral, 40.6% of the patients were taking medication, and 42.1% had one or more medical conditions, with the most common being depression or anxiety (20.1%) and thyroid disorder (8.8%). Patients reported supply issues (54.6%), nipple pain (43.8%), and tongue tie concerns (29.6%) as reasons for attending the WBC. In comparison, infant feeding mechanic challenges (35.4%), low milk supply (30.4%), and nipple issues (30.4%) were the most common WBC physician-diagnosed difficulties. The higher percentage of reported low milk supply compared to diagnosed cases indicates that many parents perceived having a low milk supply without actually having it. Education, supportive psychotherapy, and prescriptions were identified as the main WBC intervention strategies. The most common education topics included infant care discussion (77.2%), feeding guidance (74.7%), and latch education (73.4%). The most common supportive psychotherapy topic was emotional status (anxiety and adjustment reactions) (43.0%). 10.5% of the WBC dyads received a prescription, with domperidone being the most common, prescribed to 6.1% of the clinic dyads.
Conclusions
This study lays the foundation for future research within the WBC and highlights the need to expand specialized lactation care beyond the Winnipeg region, provide timely interventions or referrals (e.g. tongue-tie release), and integrate infant care and lactation education into existing services.Canada Research Chair Program by my advisor.May 202
Bite-sized history: a metric and non-metric dental trait analysis of pre-colonial Indigenous populations in the Greater Antilles
No full textRecent analyses suggest a greater diversity existed among the earliest Indigenous inhabitants of the Greater Antilles than previously thought. The pre-colonial period is broadly conceptualized into two successive chronological periods, the Archaic Age and Ceramic Age. Previous research identified biological differences between Archaic Age and Late Ceramic Age groups; however, these findings were impacted by small sample sizes and methodological issues. Further, the analysis of variation within Archaic Age and Ceramic Age populations has received less attention.
This study aimed to broaden understandings of the biological relationships between groups from different time periods, islands, and cultural horizons in the Greater Antilles. To infer biological distances, metric and non-metric dental traits were compared between four Archaic Age and six Ceramic Age sites. The first statistical approach involved analyzing the metric and non-metric dental traits through separate analyses. The second statistical approach combined the data types into a single analysis using the novel FLEXDIST software tool, representing the first implementation of this method in a Caribbean context.
Distinct variability was found between the cemeteries of Canímar Abajo, and low general biological diversity among the later Archaic Age groups. Significant differences were observed among the coeval sites at the end of the Late Ceramic Age; however, Ceramic Age groups from Cuba, Puerto Rico, and the Dominican Republic generally shared strong biological affinity. Patterns of biological continuity were seen throughout the pre-colonial period between the Archaic Age groups from Cuba with the Ceramic Age groups from Puerto Rico and the Dominican Republic. Significant differences between Archaic Age and Ceramic Age groups in Cuba suggests diverse groups cohabitated on the island. This research adds to previous knowledge about the diverse peoples and cultures present in the pre-colonial and early colonial Caribbean and the complex interaction webs they built over thousands of years.October 202
Exploring the prevalence and impact of post-COVID symptoms among individuals with Chronic Obstructive Pulmonary Disease
No full textBackground: Chronic Obstructive Pulmonary Disease (COPD) affects about 300 to 400 million individuals worldwide and has been linked to severe outcomes of COVID-19. About 10% to 30% of individuals who have COVID-19 develop post-COVID symptoms (PCS). COPD is associated with more severe cases of COVID-19 and severe COVID-19 is a known risk factor for PCS. It is possible that individuals with COPD have a higher likelihood of developing PCS. However, the prevalence and impact of PCS in individuals with COPD remains unclear.
Objectives: To explore the prevalence of PCS in COPD, assess the impact of post COVID condition on symptoms, physical activity level (PAL), health-related quality of life (HRQoL), and the use of healthcare services (UHcS) among COPD individuals, and to explore the differences in these variables between COPD individuals with and without PCS.
Methods: A cross-sectional study that used standardized instrument was collected among Manitoba adult residents. Recruitment was conducted via social media platforms (Facebook, and Instagram), support groups, walk-in clinics, pharmacies, community centers and senior facilities.
Results: 78 individuals with COPD were included, half were females, mostly aged 60-69 years, residing in urban areas. The prevalence of PCS in our group of participants with COPD was 91.3% (n=63). Most reported PCS were cough, joint pain, muscle weakness, shortness of breath at rest, and fatigue. PCS has a significant negative impact on PAL and HRQoL and declines across all EQ-5D-5L domains compared to pre-COVID status. UHcS increased significantly post COVID, except for primary and urgent care visits. We found greater decline on HRQoL among COPD individuals with PCS in 4 domains of the EQ-5D-5L and CAT scores but not in PAL, usual activity domain, EQ-VAS and UHcS compared to those without PCS.
Conclusion: COPD individuals with PCS reported a substantial burden of persistent symptoms, marked decline in PAL, reduce in HRQoL and increased UHcS. Despite the limitations and exploratory nature of this study, the findings offer valuable insights to guide safe and effective rehabilitation intervention, and to inform the planning of tailored services to meet the specific needs of this patient group.October 202
Time-Resolved X-Ray Emission Spectroscopy and Synthetic High Spin Model Complexes Resolve Ambiguities in Excited State Assignments of Transition Metal Chromophores: A Case Study of Fe-Amido Complexes
No full textTo fully harness the potential of abundant metal coordination complex photosensitizers, a detailed understanding of the molecular properties that dictate and control the electronic excited state population dynamics initiated by light absorption is critical. In the absence of detectable luminescence, optical transient absorption (TA) spectroscopy is the most widely employed method for interpreting the electron redistribution in such excited states, particularly for those with charge-transfer character. The assignment of excited state TA spectral features often relies on spectroelectrochemical measurements, where the transient absorption spectrum generated by a metal-to-ligand charge transfer (MLCT) electronic excited state, for instance, can be approximated using steady-state spectra generated by electrochemical ligand reduction and metal oxidation and accounting for loss of absorptions by the electronic ground state. However, the reliability of this approach can be clouded when multiple electronic configurations have similar optical signatures. Using a case study of Fe(II) complexes supported by benzannulated diarylamido ligands, we highlight an example of such an ambiguity and show how time-resolved X-ray emission spectroscopy (XES) measurements can reliably assign excited states from the perspective of the metal, particularly in conjunction with accurate synthetic models of ligand-field electronic excited states, leading to a re-interpretation of the long-lived excited state as a ligand-field metal-centered quintet state. A detailed analysis of the XES data on the long-lived excited state is presented, along with a discussion of the ultrafast dynamics following the photoexcitation of low-spin Fe(II)-Namido complexes using a high-spin ground-state analogue as a spectral model for the 5T2 excited state
Iranian immigrants on Instagram: potential implications for the maintenance of Farsi
No full textIn this thesis, I examine how some Iranian immigrants use Instagram to promote Farsi and express their cultural identities. I use cultural identity theory (Hall, 1990/2021) and a passive observational ethnography approach (Costello et al., 2017) to address the following questions: How do Iranian immigrants use Farsi on Instagram? And what role, if any, does Instagram play in maintaining and promoting Farsi among Iranian immigrants? My findings show that while Instagram may, in some cases, enable the presentation of Iranian cultural symbols and Farsi as a heritage language amidst the diaspora, its role in the maintenance of Farsi and the fostering of Iranian immigrant cultural identity based on Iranian heritage culture is not clear, and the use of Farsi is sometimes superficial. Some posts analyzed in this thesis reflect Hall’s (1990/2021) argument that identity is constructed through cultural memory rather than solely through physical return. In addition, some other posts describe the changes that Iranian immigrants face in maintaining Farsi or celebrating Iranian traditions abroad, which might align with Hall’s (1997/2019c) view that identity adaptation is crucial in shaping identity. However, Instagram’s commercial motives may raise concerns about the authenticity of cultural representation. Exposure to Farsi on Instagram suggests some potential for heritage language promotion among Iranian immigrants. However, this exposure is often passive and fragmented, lacking the depth necessary for meaningful linguistic engagement. While the platform may enhance Iranian cultural visibility through Farsi captions and hashtags, its emphasis on brevity, aesthetics, and commercial appeal undermines deeper linguistic engagement.October 202
Determining the soil-geosynthetic composite stiffness in an aggregate-clay system
No full textThe stiffness of soil–geosynthetic composites, denoted as KSGC, represents the initial stiffness of the interface between soil and geosynthetics under small displacements. It serves as a performance parameter for evaluating the reinforcing effect of geosynthetics in pavement systems and other geotechnical applications. This study investigates the factors influencing KSGC using large-scale pullout box tests, focusing on the effects of backfill material type, confining pressure, and geosynthetic product selection.
Confining pressure was found to have a notable effect on KSGC. Higher normal stresses generally resulted in increased stiffness due to enhanced confinement and mobilization of interfacial resistance. However, this increase showed a diminishing rate beyond certain pressure thresholds, likely due to stress redistribution and material yielding. Aperture size, rib thickness, and surface roughness were identified as key design parameters influencing the interaction behavior. The analysis also reveals that backfill type and gradation significantly affect soil–geosynthetic interaction. For geogrids, KSGC values are highly dependent on the relationship between soil particle size, aperture dimensions, and rib geometry, as mechanical interlock governs the interface response. In contrast, geotextiles, particularly nonwoven types, demonstrate less sensitivity to particle size due to their extensibility and reliance on friction. The combination of geogrid and geotextile layers yielded higher KSGC values, suggesting a synergistic interaction between frictional and passive resistance mechanisms.
The study underscores the importance of selecting appropriate geosynthetic materials based on specific site conditions and expected stress environments. Consideration of backfill properties and confining stress is critical in maximizing the reinforcing effect and ensuring long-term performance in geosynthetic-stabilized pavement systems.February 202
Examining differences in relationship quality by romantic relationship initiation pathway
No full textRecent research has highlighted that there are two distinct pathways to initiate a romantic relationship: friends-first initiation and dating-initiation. However, little research has explored potential differences between these two pathways. As friends-first initiators have a pre-existing relationship that dating-initiators do not possess, I predicted that friends-first initiators would have higher trust, satisfaction, and commitment, and lower uncertainty and jealousy compared to dating initiators. Therefore, I examined the differences in these relationship qualities between entering a romantic relationship as friends versus as strangers. Eight hundred and sixty-five university students and crowdsourced individuals (Prolific) who were in a romantic relationship at the time of the study were asked to complete an online survey about their current romantic relationship. Through multivariate analysis of variance (MANOVA), I found that individuals who were friends-first tended to have more trust, satisfaction, and commitment, and less self-uncertainty in their romantic relationships compared to dating initiators. This finding held constant even when adding individual differences, relationship length, and recruitment sample as covariates. Further, through exploratory mediation analysis, I uncovered that trust mediates the link between initiation pathway and these relationship qualities, meaning that having a pre-existing friendship prior to dating likely increases trust, and this trust leads to these other relationship quality benefits. These findings contribute to understanding how being friends-first may impact the subsequent romantic relationship, and also indicates that friends-first relationships may experience greater benefits that dating-initiators do not.October 202
Weathering processes of microplastics in the sea ice and ocean environment: an 18-month-long mesocosm study
No full textThe persistence and impact of microplastics (MPs) in marine ecosystems are of increasing concern. In recent years, sea ice has been recognized as an effective temporary reservoir for MPs in polar oceans. While many studies have reported the presence of MPs, the weathering processes of MPs and their interactions with other contaminants remain largely unknown, especially in polar oceans with a dynamic sea ice environment. This study conducted an extensive 18-month-long, outdoor mesocosm experiment to investigate the weathering processes of MPs in the marine cryosphere that involved two complete cycles of sea ice growth and melt under natural ambient conditions. Microplastics of different size, color and chemical composition were used in the study to examine the weathering processes and the interactions between microplastics with other trace metal species (e.g., mercury). By simulating a polar marine cryosphere dominated by a seasonal sea ice cover at a mesocosm scale, the study captures complex interactions between MPs and the surrounding environment. Key findings reveal that prolonged exposure to natural weathering processes, primarily due to photodegradation, biofilm formation, and seasonal sea ice dynamics, significantly alters MP surface properties and Hg accumulation efficiency in ways not observed in laboratory scale experiments. Photodegradation of MPs occurred, but to a much lesser degree than reported from laboratory studies; instead, seasonal changes in temperature, and sea ice and biofilm dynamics had a much more prominent role in the weathering and Hg accumulation. The unique natural weathering patterns found in the mesocosm study indicate that such a process cannot be easily reproduced in lab-based, short-term, single-factor studies. The study also reveals the role of weathered MPs as a medium for toxic substances such as Hg, which might present additional ecological risks when ingested by marine biota. This work promotes the understanding of the long-term fate of MPs in marine ecosystems and informs mitigation strategies, advocating for policies grounded in realistic environmental conditions. By bridging the gap between laboratory experimentation and real-world complexity, the study shows the value of the employed mesocosm approach for future research on plastic pollution, especially on its implications in the polar marine cryosphere under a rapidly changing climate.October 202
Unveiling molecular mechanisms and candidate genes for goss’s bacterial wilt and leaf blight resistance in corn through RNA-Seq analysis
No full textGoss’s bacterial wilt and leaf blight (GWLB) induced by Clavibacter nebraskensis poses a significant threat to corn production in Canada and the US. We conducted RNA-Seq analyses on two corn hybrid lines with contrasting levels of susceptibility to GWLB, 447 (susceptible) and 450 (resistant), to elucidate the molecular mechanisms underlying corn resistance to the disease. The two selected corn lines were subjected to inoculation with two isolates of C. nebraskensis exhibiting distinct levels of aggressiveness: DOAB232 (DOAB), a weakly aggressive isolate and Cn14-5-1 (BACT), a highly aggressive one, or were left untreated (CTL) Total RNA was isolated from leaf tissue in three biological replicates for each hybrid x treatment combination five days post-inoculation (dpi), a timepoint selected to capture the early transcriptional response to pathogen infection. RNA-sequencing was performed following poly-A tail isolation of the RNA on all 18 samples (6 combinations * 3 replicates). Following data cleaning and filtering of the raw RNA-seq data, unsupervised clustering, differential expression and pathway analysis was conducted. Our analysis revealed extensive transcriptional reprogramming in both resistant and susceptible lines, particularly in the susceptible corn line (447) when inoculated with the either the weak or aggressive strain of C. nebraskensis, but also in the resistant corn line when inoculated with the aggressive bacterial isolate. Inoculation of the resistant corn line (450) to the aggressive C. nebraskensis isolate, led to increased expression of photosynthesis-related and defense-associated genes, and downregulation of secondary metabolism and stress responses pathways, while inoculation of the susceptible corn line (447) with the weakly aggressive C. nebraskensis isolate led to upregulation of defense-associated genes. The functions of some of the top differentially expressed genes in each comparison are discussed within the context of understanding the molecular underpinnings of corn resistance to GWLB disease to identify targets for genetic enhancement towards higher disease resistance levels