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Evaluating the Physiological Effects and Responses that Stress has on the Brain
No full textPost-traumatic stress disorder (PTSD) remains a debilitating condition with complex neurobiological underpinnings, often co-occurring with psychiatric comorbidities and substance abuse. Despite extensive symptomatology documentation, understanding the neurobiological mechanisms, particularly in response to reward and punishment, remains elusive. Few studies have reported on the psychometric properties of reward positivity (RewP) and feedback negativity (FN), crucial for understanding valid individual difference measures. This study investigates the neural correlates of reward processing in PTSD using electroencephalogram (EEG) tasks. Participants (N = 108) recruited from Texas A&M University undergraduate research participant pool (SONA) completed a battery of psychological assessments and computerized tasks, including the Doors Task, targeting event-related potentials (ERPs). The Doors Task, a validated paradigm, assesses RewP and FN in response to monetary gains and losses. Preliminary analysis of self-report data revealed elevated anxiety and trauma exposure among few participants. EEG data cleaning is ongoing, with initial findings indicating greater reward responses to avoiding punishment among those engaging in avoidance-related thoughts and behaviors. This study contributes to elucidating the neurobiological basis of reward processing deficits in PTSD, potentially informing therapeutic interventions targeting reward systems in this population. This study aims to understand the neural processing of differential reward content to include (monetary relief of an aversive stimulus). With this information, the RISC lab is trying to determine how this may influence neurobehavioral mechanisms as well as those affected by them. This includes sustained attention, cognitive control towards both threatening and rewarding stimuli, and negative reinforcement learning. The thought process is that relief of an aversive stimulus is an understudied form of reward that has broad implications for anxiety, substance use disorders, depression, and PTSD. The goal is to provide a more in-depth understanding through collecting and calibrating relief response measurements in healthy controls. Aiming to better determine and explore several putative mechanisms underlying the tendency to engage in avoidance-related behaviors among a representative sample of community members and university students. Assess neural reward responses to avoid an aversive stimulus using electroencephalography (EEG) data recordings. Examine how individuals learn to avoid aversive sounds using a probabilistic learning task. How individuals engage cognitive control under threat (flanker task), and participants respond to different emotional content images through (pictures task). To determine and produce novel and critical data regarding the underlying mechanisms of avoidance. Method: This study will be conducted using four tasks: A modified Doors task, negative reinforcement learning, a flanker, and the emotional interrupt picture viewing task. Participants will receive each of the measures in a different controlled random order administered by RISC lab personnel from a predetermined list. Prior to beginning the computerized tasks, participants completed a comprehensive battery of self-report measures assessing cognitive-affective vulnerability factors, PTSD and related symptomology, and demographic information. Several sensors were also placed on the participants to gather data on eye movements, heart rate, skin conductance, and electroencephalography (EEG). Results: Data collection is complete, and the cleaning, processing, and reduction of the self-report and psychophysiological data is ongoing and on track to be completed by the end of the Spring 2024 semester. ��
Plasmonic Substrates for Modified Reaction Chemistry via Vibrational Strong Coupling
No full textThere has recently been intense investigation surrounding evidence that vibrational strong coupling (VSC) of molecules inside optical cavities can modify chemical reactions, even in the dark. When molecules are placed inside an optical cavity, the two systems can coherently exchange energy faster than losses to the environment, forming two new hybridized polariton states at higher and lower frequencies than the original vibrational modes. However, the theoretical community has yet to come to a consensus on how VSC may modify chemical processes, and new experimental platforms for probing key mechanisms have been lacking.
Motivated by this, we developed plasmonic nanocavities as an optical platform to study VSC-modified chemistry because the local density of optical states (LDOS) can be increased in extremely small mode volumes below the diffraction limit, which may promote higher coupling strengths. Additionally, the ���open��� cavity design allows access to probe the spatial dependence of modified chemistry, which is usually not possible in standard closed cavities. We fabricated plasmonic nanocavity substrates that demonstrate limited angle-dispersion, and therefore, can couple to any dipole orientation in deposited molecules with approximately equal efficiency, although the spatial extent of coupling is inhomogeneous due to the field distribution near the nanocavities. By placing an ensemble of molecules on top of the substrates, we demonstrate VSC to multiple vibrational modes simultaneously with molecules that are conducive to analyzing how VSC might modify phase dehydration temperatures.
Indeed, we show how the formation of polariton states decreases the stage temperature required to induce the dehydration of copper sulfate pentahydrate by as much as 14��C. Confocal Raman microscopy in conjunction with the open cavity design facilitated sub-wavelength spatial mapping of the modified chemistry, which was localized to regions with the largest LDOS. These findings underline the role of strong light-matter hybridization for enhancing energy transport between the cavity substrate and the molecules, effectively eliminating their temperature difference. This research offers critical insights into the mechanisms of VSC-modified chemistry, paving the way for novel, tailor-made catalytic processes hinging on fine-tuned energy exchange
Second return to Peleliu by Sammy Ray and Charles Ray. Photographs by Ron K. Leidich, Biologist. September 2004.
No full text40 slide Power Point presentation featuring photographs of visit to Peleliu Island. Created 2004
A Novel Class of Halite Scale Inhibitors: A Systematic Study
No full textHalite (NaCl) scaling complicates oil and gas production from many reservoirs worldwide because of its facile and fast precipitation in well tubulars or near-wellbore areas. Current industry approaches to remove halite scales via continuous or periodic freshwater treatments are often inefficient or late measures. In this study, a new class of halite scale inhibitors is studied to identify its inhibition efficiency in halite scale with benchmark halite scale inhibitor.
A modified and improved static bottle test is used. The experimental procedure is optimized for dissolving 37.50g of NaCl in 100 mL of distilled water at 80��C. After dosing inhibitor into bottle, brine is heated in an oven to ensure complete dissolution of NaCl. Solution is then kept in a switched-off oven to gradually cool down to 23��C for the following 36 hours. Precipitated halite crystals are collected, if any, then dried, and weighed. Certain experiments are performed in duplicate to assess the reproducibility of the results.
Ten out of eighteen inhibitors tested in this study have completely inhibited halite scale growth. The inhibition efficiency of effective inhibitors is 100%. More importantly, these additives are safe for the environment since most of them are food additives. In the field, these effective inhibitors not only reduce the frequency of freshwater treatments but also increase the revenue for operators by minimizing production downtime and freshwater cost.
This study introduced a new class of inexpensive and efficient halite scale inhibitors. Field application of these products will minimize the problems associated with halite scale deposition and freshwater treatments
Sensitive Detection of HIV-1 Virus Using Paper Microfluidics: A Point-of-Care Approach
No full textHuman Immunodeficiency Virus (HIV) poses a significant global public health challenge, affecting millions worldwide. HIV is a major global public health issue, with an estimated 39 million people living with this disease by 2023. While there is no cure for HIV, effective diagnostic and treatment methods have allowed those with the virus to lead healthier lives. Current HIV diagnostic methods, such as antigen/antibody dual tests and antibody tests require a minimum of 20 days after exposure for accurate detection and can be expensive. The World Health Organization (WHO) advocates for rapid, point-of-care diagnostics meeting the ASSURED criteria (affordable, sensitive, specific, user-friendly, rapid, robust, equipment-free, and accessible to end-users) to provide immediate access to care for HIV-positive individuals and reduce transmission risk.
In this thesis, we introduce a lateral flow device designed to detect miR-150-5p, a potential HIV biomarker. The assay employs colorimetric analysis to detect the microRNA sequence at sub-ng ��L^-1 levels, eliminating the need for target material amplification. The device features control and test line and exhibits a broad detection range from 0.065 pg ��L^-1 to 6500 pg ��L^-1. This technique demonstrates sensitivity for early HIV detection and holds promise for the sensitive detection of other diseases