The objective of this study was to assess low to high levels of Cognitive Workload by measuring heart rate and cortical blood flow in real-time. Four conditions were implemented into a within-subjects experimental design. Two conditions of difficulty and two conditions of trial order were used to illicit different levels of workload which will be analyzed with psychophysiological equipment. Functional Near-Infrared Spectroscopy (fNIRS) has become more prominent for measuring the blood oxygenation levels in the prefrontal cortex of individuals operating in hazardous work environments, students with learning disabilities, and in research for military training. This is due to the fNIR device being highly mobile, inexpensive, and able to produce a high-spatial resolution of the dorsolateral prefrontal cortex during executive functioning. Heart Rate will be measured by an Electrocardiogram, which will be used in concordance with fNIR oxygenation levels to predict if an individual is in a condition that produces low or high mental workload. Successfully utilizing heart rate and blood oxygenation data as predictors of cognitive workload may validate implementing multiple physiological devices together in real-time and may be a more accurate solution for preventing excessive workload.

It is now a matter of routine for the forensic scientist to obtain the genetic profile of an individual from DNA recovered from a biological stain deposited at a crime scene. Potential contributors of the stain must either be known to investigators (i.e. a developed suspect) or the questioned profile must be searched against a database of DNA profiles such as those maintained in the CODIS National DNA database. However, in those instances where there is no developed suspect and no match is obtained after interrogation of appropriate DNA databases, the DNA profile per se presently provides no meaningful information to investigators, with the notable exception of gender determination. In these situations it would be advantageous to the investigation, if additional probative information could be obtained from the biological stain. A useful biometric that could provide important probative information, and one that may be amenable to molecular genetic analysis, is the biological age of an individual. The ability to provide investigators with information as to whether a DNA donor is a newborn, infant, toddler, child, adolescent, adult, middle-aged or elderly individual could be useful in certain cases, particularly those involving young children such as kidnappings or in providing additional intelligence during terrorist investigations. Currently no validated molecular assays exist for age determination. Biological human ageing can be defined by two distinct processes, degenerative and developmental ageing. The degenerative process of ageing is based on theories which identify an increase or decrease in physiological conditions with increasing age. In contrast, the developmental process of ageing is based on the theory that as individuals increase in chronological age, there will be subtle corresponding molecular based biological changes, each requiring genes to be expressed or silenced, indicative of that particular stage of life. We investigated the degenerative process of chromosomal telomere shortening, as well as the developmental process of gene expression profiling analysis, in an attempt to identify biomarkers of biological age in a self-renewing tissue such as blood. While telomere length analysis was an ineffective method for age determination; gene expression analysis revealed three gene transcripts expressed in an age-dependent physiological manner. These species namely- COL1A2, HBE1 and IGFBP3, were found to be expressed at elevated levels in younger individuals, newborns, or post-pubertal individuals, respectively. The biological process of hemoglobin switching was also investigated for the possibility of determining human age. While experimenting with the potential of using the gamma-hemoglobin chains, as newborn specific gene candidates, we serendipitously discovered four novel truncated transcripts, which we have termed HBG1n1, HBG1n2, HBG2n2 and HBG2n3; whose expression was restricted to whole-blood newborn samples and specific fetal tissues. The molecular origin of these transcripts appears to be at the RNA level, being produced by specific rearrangement events occurring in the standard gamma hemoglobin transcripts (HBG1 and HBG2), which yield these new isoforms that are expressed in a highly regulated tissue specific manner.

Electrochemical biosensors are renowned for their ability to detect a wide range of analytes in biological fluids for clinical diagnosis. The implementation of biomarkers in electrochemical biosensors for clinical diagnosis is essential for the specific and accurate diagnosis of the disease with high sensitivity and selectivity. Therefore, this thesis evaluates the challenges pertaining to the stability, reproducibility, and obtaining a low limit of detection for the internal/external biomarkers associated with two distinct electrochemical biosensors. The first study tackles the challenge of detecting low analyte concentrations in a label-free biosensor. It introduces an innovative label-free electrochemical biosensing method for the detection of glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP) to predict Coronary Heart Disease (CHD) progression using tailored redox probes, proposing a dual biomarker biosensing platform for future research. Calibration curves reveal an LOD of 5 mg/mL in PBS (8) FeCN (II) and 6 mg/mL in SB for a linear range of 0 – 30 mg/mL of HbA1c. Similarly, an LOD of 0.007 mg/mL and 0.008 mg/mL in PBS (7.4) PcA-NO2 and SB, respectively, is reported for a linear range of 0 – 0.05 mg/mL of CRP. The second study focuses on stabilizing a biomolecule-free sensor for the ultra-low detection of Δ9-tetrahydrocannabinol (THC) in roadside testing. Pre-depositing THC, an external biomarker for drug-impaired driving, onto the biosensor's working electrode enhances its interaction with analytes. However, THC's oxidative nature compromises sensor stability during manufacturing. Consequently, optimal electrode storage conditions were explored, indicating frozen storage as ideal for up to six months, effectively preventing THC oxidation at -18°C, while degradation occurs at 4°C. Modified electrodes stored under optimal conditions exhibit improved calibration curves when exposed to various THC samples. / Thesis / Master of Applied Science (MASc) / An electrochemical biosensor is a sensing device with the ability to detect biological species via the transduction of a specific biological event into electrochemical signals. These sensors are extremely useful for the detection of analytes in biological fluids for clinical diagnostics, to determine the presence or absence of diseases. This manuscript addresses the challenges associated with the stability, reproducibility, and the low limits of detection associated with screen-printed carbon electrodes used in electrochemical biosensing. Subsequently, due to the strong correlation between glycated hemoglobin (HbA1c) and C-reactive protein (CRP) to connote the risk of contracting coronary heart disease (CHD), the manuscript presents a novel label-free electrochemical biosensing method for the detection of HbA1c and CRP with low detection limits. Secondly, the manuscript identifies ambient storage conditions for the long-term stability of a biomolecule-free sensing device for the roadside detection of ultra-low concentrations of Δ9-tetrahydrocannabinol (THC).

Cardiovascular disease (e.g., myocardial infarction, stroke, coronary artery disease) is the leading cause of death and disability worldwide. There is a growing body of literature that indicates sexual minority (e.g., gay, lesbian, bisexual, queer) adults are at a higher risk of cardiovascular disease than their heterosexual counterparts. The aim of this dissertation was to identify factors that contribute to the cardiovascular health (CVH) disparities that have been observed among sexual minority individuals. Guided by an adaptation of the minority stress model of CVH among sexual minority individuals, this dissertation includes three studies. In the first study (i.e., Chapter 2), we conducted a scoping review of the literature that investigated social determinants of cardiovascular health among sexual minority adults. Although findings were mixed, several social determinants of health were found to influence the CVH of sexual minority adults. For instance, sexual minority adults who lived in environments that were more supportive of sexual and gender minority people had lower odds of being overweight or obese. In the second study (i.e., Chapter 3), we used data from a racially and ethnically diverse sample of sexual minority women to examine the associations of family-related factors (i.e., sexual identity disclosure and family social support) with self-reported incident hypertension. Additionally, we examined whether these associations were moderated by race/ethnicity and sexual identity, or mediated by depressive symptoms. We found that higher levels of family social support were associated with lower levels of depressive symptoms among sexual minority women. However, family-related factors were not associated with self-reported incident hypertension. Further, race/ethnicity and sexual identity did not moderate the associations between family-related factors and reported incident hypertension. In the third study (i.e., Chapter 4), we used data from a nationally representative sample of adults to investigate sexual identity differences in ideal CVH (as defined by the American Heart Association’s Life Simple 7) and whether these associations were mediated by depressive symptoms. Compared to exclusively heterosexual women, mostly heterosexual and lesbian women were less likely to meet ideal criteria for tobacco use. In contrast, lesbian women were more likely to meet ideal criteria for glycosylated hemoglobin than exclusively heterosexual women. Among men, relative to exclusively heterosexual men, mostly heterosexual men were less likely to meet ideal criteria for tobacco use. Gay and bisexual men were less likely to meet ideal criteria for physical activity, whereas gay men were more likely to meet ideal criteria for body mass index compared to exclusively heterosexual men. Bisexual men were less likely to meet ideal criteria for blood pressure relative to exclusively heterosexual men. Depressive symptoms were found to partially mediate the association between sexual identity and physical activity only among mostly heterosexual women. Overall, these dissertation findings highlight CVH disparities among sexual minority adults. Clinicians should be educated about the CVH disparities that have been documented among sexual minority adults to provide personalized and culturally competent care. Results also indicate there is a need to develop behavioral interventions tailored specifically to the needs of sexual minority adults to improve their CVH outcomes and reduce CVH-related disparities.

Current screening tests for type 2 diabetes mellitus (T2DM) identify less than 50% of undiagnosed T2DM patients and provide no information about how the disease will develop in prediabetic patients. Here, twenty-nine protein glycation sites were quantified after tryptic digestion of plasma samples at the peptide level using tandem mass spectrometry and isotope-labelled peptides as internal standard. The glycation degrees were determined in three groups, i.e., 48 patients with a duration of T2DM exceeding ten years, 48 non-diabetic individuals matched for gender, BMI, and age, and 20 prediabetic men. In long-term controlled diabetic patients, 27 glycated peptides were detected at significantly higher levels, providing moderate diagnostic accuracies (ACCs) from 61 to 79%, allowing a subgrouping of patients in three distinct clusters. Moreover, a feature set of one glycated peptides and six established clinical parameters provided an ACC of 95%. The same number of clusters was identified in prediabetic males (ACC of 95%) using a set of eight glycation sites (mostly from serum albumin). All patients present in one cluster showed progression of prediabetic state or advanced towards diabetes in the following five years. Overall, the studied glycation sites appear to be promising biomarkers for subgrouping prediabetic patients to estimate their risk for the development of T2DM.

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