Category archives: Research

A community of trillions of commensal bacteria inhabit the gastrointestinal tract, collectively known as the intestinal microbiota. The gut microbes are essential for the development and functioning of the enteric nervous system. Approximately two-thirds of the cell bodies of all enteric neurons are gathered in the myenteric plexus, an intricate network of neurons and glial cells that primarily regulate gut neuromuscular activity. Studies in laboratory mice have observed that antibiotic treatment leads to a reduction in microbial abundance and diversity within the intestine, and these findings are correlated with enteric nervous system structural abnormalities. Specifically, antibiotic-treated mice have an abnormal myenteric plexus, which is characterized by a reduction in myenteric neuron numbers and ganglia area. However, it is unknown whether these effects occur in wild Peromyscus mice that are exposed to a natural bacterial flora. The goal of this study was to evaluate the effects of antibiotic exposure on the colonic neurons of the myenteric plexus in wild Peromyscus mice. Thirty-two wild-caught adult male Peromyscus mice were divided into control and antibiotic-treated groups. Whole mount preparations of longitudinal muscle with adherent myenteric plexus were prepared and alterations in colonic neuron and ganglia numbers were assessed by immunohistochemistry analysis. Antibiotic-treatment reduced the total number of colonic enteric neurons/mm2 and the total number of ganglia per myenteric plexus. Our results suggest that antibiotic-induced microbial dysbiosis affects the colonic neurons and ganglia of wild Peromyscus mice similarly to laboratory mice. We showed that the antibiotic-driven changes in neuronal density and ganglia arrangement are inducible in wild Peromyscus species that are exposed to real world bacteria.

Cerebral vascular injury is a common phenomenon after traumatic brain injury (TBI), with complications including vascular inflammation, decreased cerebral blood flow, and increased vessel tortuosity. Promoting cerebrovascular health may therefore be a useful therapeutic intervention after TBI. ApoA-I, the major protein constituent of circulating high-density lipoproteins (HDL) are an attractive target due to its vasoprotective and anti-inflammatory roles in periphery vessels, but little is known on whether these benefits extend to the brain. To address this gap in knowledge, this study was designed to test the novel hypothesis that ApoA-I deficiency would worsen acute vascular and inflammatory outcomes in mice after Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) TBI. ApoA-I Knockout (ApoA-I KO) and WT mice underwent single moderate-severe TBI. Histopathological outcomes at 6hr and 2 days (2D) post-injury were assessed. ApoA-I KO mice exhibited greater Intercellular Adhesion Molecule 1 (ICAM-1), a marker for vascular permeability, in the cortex at 2D post-TBI compared to WT controls, and a subtle increase in brain pro-inflammatory cytokine levels. These results suggest the role of ApoA-I in protecting against TBI induced inflammation.

Recent studies have suggested that adolescent cancer may have better survival outcomes when treated at paediatric centres, which better emphasize enrolment in clinical trials and have more capacity to support the social and emotional needs of adolescents. This study investigated 616 cancer cases in adolescents aged 15-18 from 1995 to 2010 in British Columbia, Canada with data from the Childhood, Adolescent, and Young Adult Cancer Survivors Research (CAYACS) Program of the BC Cancer Research Agency (BCCA). This study examined whether referrals to the adult centres BC Children’s Hospital (BCCH) or BCCA were influenced by age, socioeconomic status, rurality, seasonality, radiotherapy treatment, different diagnoses based on the International Classification of Childhood Cancer (ICCC), and driving time to each centre. Between 1995 and 2010, only 27% of adolescent cancer patients in BC were referred to the BCCH, the only paediatric oncology centre in BC. Rural patients might have limited accessibility to BCCH, despite referral, due to travel restrictions and costs. As a result, patients are less likely to be referred to their closest cancer treatment centre as driving time increases (OR 0.995, P= 1.9e-10). Odds ratios of each modifier to BCCA or BCCH were calculated using univariate and multivariate logistic regression models in R Studio 3.5.1. Overall, 80% of younger adolescent (age 15-16) were referred to BCCH and only 14% of older adolescents (age 17-18) were referred to BCCH, which suggested that older adolescents were less likely than younger adolescents to be referred to BCCH (P= <2e-16). Additionally, leukaemia and Central Nervous System (CNS) cancer patients were more likely than all other patients to be referred to BCCH (P= 0.0014). The study of referral patterns is an essential factor when determining adolescent cancer survival rate.

Wildlife cameras allow conservation scientists to monitor wildlife. However, there are performance limitations associated with wildlife cameras that must be understood prior to their use. This study compared two wildlife camera models, the Spypoint Solar Trail and the Reconyx Hyperfire 2, on behalf of Calgary Captured, a collaborative project between the Miistakis Institute and the City of Calgary to determine wildlife occupancy in Calgary’s Natural Area Parks. The camera models were set up in pairs at 10 sites. There was no significant difference in detections of white-tailed deer (Odocoileus virginianus) or coyotes (Canis latrans) by either model, but the Reconyx cameras successfully captured two species that the Spypoint model failed to detect: bobcat (Lynx rufus) and deer mouse (Peromyscus maniculatus). The Reconyx cameras had fewer trap days because the Nickel Metal Hydride (NiMH) batteries supplied by Calgary Captured consistently failed in cold weather, whereas the Spypoint cameras’ solar panels continued to function through the duration of the study. Despite having had fewer trap days, the Reconyx cameras captured more species than did the Spypoint cameras. There was no significant difference in the number of false positives and false negatives produced by the two models, but only the Spypoint cameras produced malfunctioned images. For projects like Calgary Captured, the Reconyx Hyperfire 2 is a more effective camera model than the Spypoint Solar Trail because it captures more species and is less prone to malfunction. The results of this study also highlight the importance of choosing appropriate batteries and settings for the camera model in question to ensure successful use.

We calculate the engine efficiency of a Leidenfrost droplet transport system to assess application for various industrial processes. The engine relies on the Leidenfrost effect to transport water droplets in a straight line across a superheated aluminium surface with ratchet-like topography. The engine efficiency of such a system has not been calculated in the literature thus far. Acceleration-time data was collected using Logger Pro 3® motion-tracking software and mechanical work was calculated using a midpoint Riemann sum. A power meter measured total power input at a constant rate. Average trial times were used to determine the power input for each trial, and engine efficiencies were subsequently calculated. Droplet volume and ratchet angle were varied as parameters in attempt to optimize engine efficiency. Our results give an extremely low average percent efficiency (2.86E-07%), which agrees with previously reported results for an analogous turbine system, to an order of magnitude. Varying the ratchet angle does not affect engine efficiency to any statistically meaningful extent. Increasing droplet volume in the 15-35 µL range tends to marginally improve engine efficiency for steep ratchet angles.

The aim of the present experiment was to study the transmission of sound through a building by means of replicating a small-scale model of a floor and ceiling apparatus. Therefore, the relationship between input sine wave frequency and sound intensity through a closed apparatus was analyzed. The sound absorbance of various sound insulating materials was compared, and resonance properties of the apparatus was also considered. Sound intensity trends were investigated for frequencies within the human hearing range (up to the order of magnitude of 10,000 Hz), and different soundproofing material types (porous absorbers and resonators) were compared. It appears that the input sound wavelength (relative to the container size), as well as sound absorption coefficient were both major factors in transmitted sound’s intensity. Porous absorbers were found to be the most robust material type at both resonance and non-resonance modes, and the optimal soundproofing material was the stone wool insulator (Material 2).

Despite distribution of millions of free mosquito nets in Angola, malaria remains the primary cause of mortality in young children, accounting for 35% of deaths among children under five (CU5). Our objectives were first to examine the association between malaria knowledge and bednet use for CU5, and second, to investigate the impact of multivariable logistic regression to analyze responses from a representative sample of women aged 15–49 from the Angola Malaria Indicator Survey (2011). Approximately 44% of respondents with CU5 (n=6,576) owned at least one bednet for sleeping, and of those 87.4% identified mosquitos as a cause of malaria. Adjusting for respondents’ age, region, and education, those reporting mosquitos as a cause of malaria had 1.7 (95%CI: 1.3–2.2) times the odds of bednet use for CU5 compared to those not reporting mosquitos as a malaria cause. Exposure to behaviour change communication (i.e. malaria messaging) increased the odds of bednet use where messaging encouraged sleeping under mosquito nets (OR: 1.3, 95%CI: 0.9–1.7). This study provides evidence of a positive association between malaria knowledge and bednet use, indicating that along with widescale distribution of bednets for malaria prevention, public health efforts in Angola should focus on increasing awareness and promoting bednet usage through targeted risk communication.