This experimented proposed to test the relationships between self-reported hostility and both facial muscle tone and cardiovascular functioning. Based on previous research, it was proposed that individuals high in self-reported hostility would show increased cardiovascular reactivity in response to a physical stressor (the cold-pressor task). Additionally, based on the integration of multiple lines of research, it was proposed that individuals with high levels of self-reported hostility would show asymmetric facial tone, with greater muscle activation at the left-hemiface. Results showed increased cardiovascular responding in the high-hostile participants following exposure to the cold-pressor task. Additionally, the individuals with high levels of self-reported hostility did show asymmetric facial tone, with increased left-hemifacial EMG values. These differences were present prior to exposure to the cold-pressor task, and were increased following the stressor. Results supported the literature showing increased cardiovascular responding to stress in high-hostile individuals, and also supported the proposed relationship between right orbitofrontal functioning and hostility. / Ph. D.

Anxiety and worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. This study examined cardiovascular responses in high and low worriers to a range of laboratory tasks. The aim of this study was to determine if there is a task-specific relationship between worry and aberrant cardiovascular responding. Forty-one undergraduate women were recruited online to form low and high worry groups by use of the Penn State Worry Questionnaire. Four common laboratory tasks and two conditions designed to elicit worry and relaxation were used: hand cold pressor, mental arithmetic, orthostatic position, supine position, worry imagery, and relaxation imagery. Heart rate, heart rate variability, impedance cardiography, and blood pressure indices were collected to assess task reactivity and recovery, particularly in relation to autonomic nervous system activity. The high worry group had significantly higher heart rates throughout the study. The low worry group presented increased cardiovascular recovery to various tasks. The high worry group during task and post-task periods also increased parasympathetic withdrawal and sympathetic activation. The results of the study suggest that high worriers have decreased vagal control of the heart. The implications of this study suggest a potential link between the post-task period in high worriers and cardiovascular disease. Further research is recommended. / Master of Science

Increased stress levels due to parenting have been shown to correlate to harsher parenting responses towards children (Belsky, 1984). Mindfulness, however, suggests the ability to focus on the present moment in a nonjudgmental and nonreactive manner. Similarly, parents with increased mindfulness have reported more open dialogue and warmth with their child (Williams & Wahler, 2010). Few studies have examined an ecologically valid test measuring the constructs of stress reactivity together with parent and child observed interaction. This study examined the moderating role of mindfulness and its effect on the relationship between parenting stress reactivity and parent response to child. Thirty-nine mother and child dyads participated in a validated activity-based parent-child interaction task designed to measure the level of maternal criticism directed toward child via behavioral coding. Mother's heart rate (HR) was monitored to determine the physiological measure of stress reactivity. Mothers also completed self-report forms to indicate levels of mindfulness, perceived stress-reactivity and parenting feelings. Results demonstrated significant main effects for parent self-reported levels of stress reactivity to social challenges and mindful non-reactivity on self-reported parent negative feelings; however, these main effects were better accounted by mother depression, stress, and child age. Mindfulness significantly predicted in-lab levels of mother critical response to child. Additionally, results indicated a significant interaction between mindfulness and perceived stress reactivity, such that mindfulness predicted less criticism toward the child in parents who reported low stress reactivity. Given the low sample size and subsequent low power, results should be viewed with caution. / Master of Science

This study investigated the roles of negative affect and cardiovascular reactivity on the attributional responding of hostile males. College males were screened with the Cook-Medley Hostility Scale (Cook & Medley, 1954). High and low hostile males were assigned to an arousal inducing (serial subtraction by 7's) or a non-arousal inducing condition (serial subtraction by 1's). Cardiovascular reactivity and self-report of affect were measured to the serial subtraction task. After the task was completed, the participant listened to a vignette (provocative or neutral) which depicted an interpersonal situation. The participant answered questions about the scene to assess attributional responding. The arousal-inducing condition was associated with significantly greater changes in systolic and diastolic blood pressure and heart rate and a higher level of self-reported negative affect than the non-arousal inducing condition. More negative attributions were reported for provocative than neutral scenes. Males in the arousal inducing condition made more negative attributions to neutral scenes than males in the non-arousal condition. There was no significant effect of arousal condition on the negative attributions to provocative scenes. Hostility did not influence the relationship between arousal condition and self-reported affect or arousal condition and attributional responding. This study showed that inducing cardiovascular reactivity prior to a neutral encounter with a partner can affect the males' perception of the potentially neutral encounter. / Master of Science

A cadmium-aluminum shield for the V.P.I. subcritical reactor was designed and constructed. Aluminum provides structural strength. Suitable access to fuel and experimental facilities was provided. Experimentally it was determined that the shield is opaque to an influx of thermal neutrons. This is manifested by a depression in neutron density near the boundaries of the pile when the shielded and unshielded region counting rates are compared. The natural-uranium slugs and the highly radioactive source are padlocked within the shield. The assembly is also protected from contamination. Practically no additional biological protection is afforded by the shield due to the neutron-gamma reaction in cadmium. / Master of Science

Blast neurotrauma represents a significant mode of traumatic injury to the brain. The incidence of blast neurotrauma is particularly high amongst military combat personnel and can be debilitating and endure clinically for years after injury is sustained. Mechanically, blast represents a unique and complex loading paradigm associated with compressive shock waves that propagate out from an explosive event and interact with the head and other organs through high-rate loading. When subjected to such insult, brain cells undergo characteristic injury responses which include neuroinflammation, oxidative stress, edema and persistent glial activation. These features of the injury have emerged as important mediators of the chronic brain damage that results from blast. Astrocytes have emerged as a potential therapeutic target because of their ubiquitous roles in brain homeostasis, tissue integrity and cognitive function. This glial subtype has a characteristic reactive response to mechanical trauma of various modes. In this work, custom in vitro injury devices were used to characterize functional models of astrocyte reactivity to high-rate insult to study mechano-stimulation mechanisms associated with the reactive phenotype. The working hypothesis was that high-rate overpressure exposure would cause metabolic aberrations, cell junction changes, and adhesion signal transduction activation, all of which would contribute to astrocyte response and reactivity. Astrocyte cultures were exposed to a 20 psi high-rate overpressure scheme using an underwater explosion-driven device. Astrocytes experienced dynamic energetic fluctuations in response to overpressure which were followed by the assumption of a classically defined reactive phenotype. Results indicated specific roles for cationic transduction, cell junction dynamics (gap junction and anchoring junctions) and downstream signal transduction mechanisms associated with adhesion alterations in onset of the astrocyte reactive phenotype. Investigation into adhesion signaling regulation by focal adhesion kinase in 2D and 3D cultures was also explored to better understand cellular reactivity as a function of extracellular environment. Additionally, another underwater in vitro device was built to study combination effects from overpressure and fluid shear associated with insult. Overall, the combined studies offer multiple mechanisms by which to explore molecular targets for harnessing astrocytes' potential for repair after traumatic injury to the brain. / PHD / Blast neurotrauma represents a significant mode of traumatic injury to the brain. The incidence of blast neurotrauma is particularly high amongst military combat personnel in which close to 80% of the injuries sustained in combat are attributed to explosive mechanisms. This injury, like other traumatic brain injuries, can be debilitating and result in altered quality of life for years after injury is sustained. There is a critical need to understand how brain cells are injured by and respond to blast loading in order to develop effective therapeutic strategies. The following work approaches this problem through the use of cellular models of blast-type insult. Custom injury devices were used to develop models of brain cell reactive response to high-rate insult based on experimental simulations of blast neurotrauma. In particular, a sub-type of brain cells called astrocytes were studied. Astrocytes have emerged as a potential therapeutic target because of their ubiquitous roles in brain homeostasis, tissue integrity and cognitive function. The working hypothesis was that high-rate overpressure exposure would cause metabolic aberrations, cell junction changes, and adhesion signal transduction activation, all of which would contribute to astrocyte response and reactivity. Astrocytes experienced dynamic energetic fluctuations in response to overpressure which were followed by the assumption of a classically defined reactive phenotype. Results indicated specific roles for cationic transduction, cell anchorage and downstream signaling mechanisms associated with adhesion alterations in onset of the astrocyte reactive phenotype. Investigation into adhesion signaling regulation by focal adhesion kinase in 2D and 3D cultures was also explored to better understand cellular reactivity as a function of extracellular environment. Additionally, another underwater cell injury device was built to study combination effects from overpressure and fluid shear associated with insult. Overall, the combined studies offer multiple mechanisms by which to explore molecular targets for harnessing astrocytes’ potential for repair after traumatic injury to the brain.

Stress is a concept that can be studied using a variety of theoretical approaches, with a focus on the individual’s perceptions, the external stressor, or the physiological reactions of stress responding. However these approaches are often used independently, when they can be used complementarily to understand the nuanced relationship between the individual and the situation when appraising stressors as challenges or threats. The current study examined the relationship between individual differences in perceptions, situational strength (both as a categorical and a continuous predictor), and physiological reactions in a leadership task. Situational strength and leadership self-efficacy were found to interact, such that those high is LSE reported more appraisals of challenge as situational strength increased. / Master of Science / Stress is a widely known concept that has been studied in various ways (individual perceptions, situational characteristics, physiology, etc.). However these approaches are often used independently, when they can be used together to more fully understand the process of how individuals appraise stressors. The current study examined the relationship between the previously mentioned approaches within a leadership task. Situational strength and leadership self-efficacy (LSE), or one’s perceived capabilities to perform leadership duties, were found to interact, such that those high is LSE reported more appraisals of challenge as situational strength increased.

No / Investigations of structural reactivity, molecular interactions and vibrational characterization of pharmaceutical drugs are helpful in understanding their behaviour. The aim of this study is to determine the molecular, electronic and chemical properties of the antibiotic drug nitrofurantoin (NF), after cocrystallisation with 3-aminobenzoic acid (3ABA) and to understand how those changes lead to variation of properties in the cocrystal NF–3ABA. NF–3ABA formation is explained by stabilization via the hydrogen-bond network between NF and 3ABA molecules. It is thoroughly characterized by IR, Raman and CP-MAS solid-state 13C NMR techniques, along with quantum chemical calculations. The results of IR, Raman, and 13C NMR analyses showed that imide N–H23 and C12[double bond, length as m-dash]O of NF interact with the acid C[double bond, length as m-dash]O and –OH groups in 3-ABA, respectively. Therefore the IR, Raman, and 13C NMR spectra verified the formation of N–H⋯O and O–H⋯O hydrogen bonds. To study hydrogen bonding interactions theoretically in NF–3ABA, two functionals B3LYP and wB97X-D have been used. A comparison is made between the results obtained by B3LYP and those predicted at the wB97X-D level. It is found that wB97X-D is best applied density functional theory (DFT) functional to describe the hydrogen bonding interactions. The strength and nature of hydrogen bonding in NF–3ABA have been analysed by quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis. To validate the results obtained by QTAIM theory and to study the long-range forces, such as van der Waals interactions, the steric effects in NF–3ABA, the reduced density gradient (RDG) and the isosurface have been plotted using Multiwfn software. QTAIM and isosurface analysis suggested that the hydrogen bonding interactions present in NF–3ABA are moderate in nature. The calculated HOMO–LUMO energy gap shows that NF–3ABA is more active than NF and 3ABA. Chemical reactivity descriptors are calculated to understand the various aspects of pharmacological sciences. Chemical reactivity parameters show that NF–3ABA is softer and chemically more reactive than NF. The results suggest that cocrystals can be a feasible alternative for positively changing the targeted physicochemical properties of an active pharmaceutical ingredient (API). / Royal Society of Chemistry for the mobility grant (2015/17); DST (New Delhi) under the DST purse programme; UGC under the BSR meritorious fellowship scheme; DST, India under the Indo-Brazil project

Defensive hostility has been attributed as an early risk factor of coronary heart disease. The autonomic characteristics of high defensive, high hostile (HD) and low defensive, high hostile (LD) men and women were assessed with a variety of cardiovascular (CV) measures. Reactivity and recovery to an active laboratory stressor (video game, VG) and a passive laboratory stressor (hand cold pressor, CP) of 15 HD men, 16 LD men, 16 HD women, and 16 LD women were recorded. It was predicted that the CV patterning associated with the HD participants would display more sympathetic and less vagal control as well as the least pronounced recovery from the stressors in comparison to LD participants. Results revealed differential CV responses to the lab tasks by group. HD women displayed consistently high levels of low frequency power heart rate variability (HRV) during baseline and across conditions. HD men exhibited significantly pronounced heart rate reactivity and reduced high frequency power HRV to the CP task in comparison to LD men. Interestingly, LD women displayed weaker blood pressure (BP) recovery to the VG in comparison to HD women, whereas the opposite pattern was observed in BP recovery to the CP. These results suggest that defensiveness and sex may moderate the CV reactivity and recovery to different types of stressors in hostile participants. / Master of Science

Divorce is a stressor associated with long-term health risk, though the mechanisms of this effect are poorly understood. Cardiovascular reactivity is one biological pathway implicated as a predictor of poor long-term health after divorce. A sample of recently separated and divorced adults (N = 138) was assessed over an average of 7.5 months to explore whether individual differences in heart rate variability—assessed by respiratory sinus arrhythmia—operate in combination with subjective reports of separation-related distress to predict prospective changes in cardiovascular reactivity, as indexed by blood pressure reactivity. Participants with low resting respiratory sinus arrhythmia at baseline showed no association between divorce-related distress and later blood pressure reactivity, whereas participants with high respiratory sinus arrhythmia showed a positive association. In addition, within-person variation in respiratory sinus arrhythmia and between-persons variation in separation-related distress interacted to predict blood pressure reactivity at each laboratory visit. Individual differences in heart rate variability and subjective distress operate together to predict cardiovascular reactivity and may explain some of the long-term health risk associated with divorce.