Publications by authors named "Thayer R"

Sexual reproduction requires the choreographed interaction of female cells and molecules with sperm and seminal fluid. In internally fertilizing animals, these interactions are managed by specialized tissues within the female reproductive tract (FRT), such as a uterus, glands, and sperm storage organs. However, female somatic reproductive tissues remain understudied, hindering insight into the molecular interactions that support fertility.

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Butterfly scales are among the richest natural sources of optical nanostructures, which produce structural color and iridescence. Several recurring nanostructure types have been described, such as ridge multilayers, gyroids and lower lamina thin films. While the optical mechanisms of these nanostructure classes are known, their phylogenetic distributions and functional ranges have not been described in detail.

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Objectives: Older adults experiencing mild cognitive impairment (MCI) may benefit from compensatory cognitive training (CCT). This study investigated the feasibility of telehealth CCT among older adults with MCI.

Methods: Adults age 55+ with MCI ( = 28) and a care partner ( = 18) participated in telehealth CCT.

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Several lines of evidence suggest that older adults (aged 65+) sharply increased their cannabis use over the last decade, highlighting a need to understand the effects of cannabis in this age group. Pre-clinical models suggest that cannabinoids affect the brain and cognition in an age-dependent fashion, having generally beneficial effects on older animals and deleterious effects on younger ones. However, there is little research on how cannabis affects the brains of older adults or how older adults differ from younger adults who use cannabis.

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More older adults are using cannabis for recreational and/or medical purposes, but most studies examining cognitive function and cannabis use do not include older adults. The current small pilot study sought to compare cognitive function and emotional functioning among adults age 60 and older who were regular, primarily recreational cannabis users ( = 28) and nonusers ( = 10). A bimodal distribution was observed among cannabis users such that they had either initiated regular use more recently ("short-term" users; ≤7 years, = 13) or earlier in life ("long-term" users; ≥19 years, = 15).

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In diverse organisms, nanostructures that coherently scatter light create structural color, but how such structures are built remains mysterious. We investigate the evolution and genetic regulation of butterfly scale laminae, which are simple photonic nanostructures. In a lineage of buckeye butterflies artificially selected for blue wing color, we found that thickened laminae caused a color shift from brown to blue.

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Importance: Given the prevalence of alcohol, cannabis, and tobacco use during adolescence, it is important to explore the relative relationship of these three substances with brain structure.

Objective: To determine associations between recent alcohol, cannabis, and tobacco use and white and gray matter in a large sample of adolescents.

Design, Setting, And Participants: MRI data were collected in N = 200 adolescents ages 14-18 (M = 15.

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Exploring associations among cannabis use, brain structure, and cognitive function in older adults offers an opportunity to observe potential harm or benefit of cannabis. This pilot study assessed structural magnetic resonance imaging in older adults who were either current cannabis users (n = 28; mean age 69.8 years, 36% female) or nonusers (n = 28; mean age 66.

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Focused ion beam milling of ∼200 nm polymer thin films is investigated using a multibeam ion microscope equipped with a gallium liquid metal ion source and a helium/neon gas field-ionization source. The quality of gallium, neon, and helium ion milled edges in terms of ion implantation artifacts is analyzed using a combination of helium ion microscopy, transmission electron microscopy and light microscopy. Results for a synthetic polymer thin film, in the form of cryo-ultramicrotomed sections from a co-extruded polymer multilayer, and a biological polymer thin film, in the form of the base layer of a butterfly wing scale, are presented.

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Background: California's tobacco tax increased by $2.00 per pack in 2017. Although such increases are among the most effective tobacco control strategies, little is known about their impact from the perspective of corner store owners in low-income neighbourhoods with high concentrations of tobacco outlets.

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In low-income urban communities across the United States and globally, small stores frequently offer processed foods, sodas, alcohol, and tobacco but little access to healthy products. To help address this problem, the city of San Francisco created a healthy food retailer incentive program. Its success depends, in part, on retailers' willingness to participate.

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Background: Identifying cognitive and neural mechanisms of decision making in adolescence can enhance understanding of, and interventions to reduce, risky health behaviors in adolescence. Delay discounting, or the propensity to discount the magnitude of temporally distal rewards, has been associated with diverse health risk behaviors, including risky sex. This cognitive process involves recruitment of reward and cognitive control brain regions, which develop on different trajectories in adolescence and are also implicated in real-world risky decision making.

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Background: The developmental period of adolescence marks the initiation of new socioemotional and physical behaviors, including sexual intercourse. However, little is known about neurodevelopmental influences on adolescent sexual decision-making.

Purpose: We sought to determine how subcortical brain volume correlated with condom use, and whether those associations differed by gender and pubertal development.

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In urban "food swamps" like San Francisco's Tenderloin, the absence of full-service grocery stores and plethora of corner stores saturated with tobacco, alcohol, and processed food contribute to high rates of chronic disease. We explore the genesis of the Tenderloin Healthy Corner Store Coalition, its relationship with health department and academic partners, and its contributions to the passage and implementation of a healthy retail ordinance through community-based participatory research (CBPR), capacity building, and advocacy. The healthy retail ordinance incentivizes small stores to increase space for healthy foods and decrease tobacco and alcohol availability.

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Studies have identified strong associations between D2 receptor binding potential and neural responses to rewarding stimuli and substance use. Thus, D2 receptor perturbations are central to theoretical models of the pathophysiology of substance dependence, and epigenetic changes may represent one of the fundamental molecular mechanisms impacting the effects of alcohol exposure on the brain. We hypothesized that epigenetic alterations in the promoter region of the dopamine D2 receptor (DRD2) gene would be associated with cue-elicited activation of neural reward regions, as well as severity of alcohol use behavior.

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Adolescence is a neurodevelopmental period of heightened sexual risk taking. Neuroimaging can help elucidate crucial neurocognitive mechanisms underlying adolescent sexual risk behavior, yet few empirical studies have investigated this neural link. To address this gap in the literature, we examined the association between neurocognitive function during response inhibition-a known correlate of risk behaviors-and frequency of intercourse without a condom among adolescents.

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Objective: Alcohol use disorders (AUDs) are associated with decreased gray matter, and neuroinflammation is one mechanism through which alcohol may confer such damage, given that heavy alcohol use may promote neural damage via activation of toll-like receptor 4 (TLR4)-mediated inflammatory signaling cascades. We previously demonstrated that TLR4 is differentially methylated in AUD compared with control subjects, and the present study aims to extend this work by examining whether TLR4 methylation moderates the relationship between alcohol use and gray matter.

Method: We examined TLR4 methylation and gray matter thickness in a large sample (N = 707; 441 males) of adults (ages 18-56) reporting a range of AUD severity (mean Alcohol Use Disorders Identification Test score = 13.

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Background And Aims: Chronic alcohol use is associated with lower gray matter volume, and we reported recently that alcohol use showed negative associations with widespread gray matter (GM) volume even among young adults. The current study aimed to test the strength of association between (1) alcohol use and GM volume; (2) alcohol use and white matter (WM) integrity; (3) cannabis use and GM volume; and (4) cannabis use and WM integrity among adults and adolescents.

Design And Setting: General linear models within large pooled cross-sectional samples of adolescents and adults who had participated in studies collecting substance use and neuroimaging data in the southwestern United States.

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Chronic alcohol use is associated with declines in gray matter (GM) volume, as is the normal aging process. Less apparent, however, is how the interaction between aging and heavy alcohol use affects changes in GM across the lifespan. There is some evidence that women are more vulnerable to the negative effects of alcohol use on GM than men.

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Effectively treating addiction is a challenge among any population, and treatment for adolescents may be particularly challenging in the context of ongoing neurodevelopment, which may alter the brain's initial response to substances as well as its response to treatment. One way to improve treatment outcomes for youth is to use a translational perspective that explicitly connects cognitive and neurodevelopmental fields with the field of behavioral therapies. This integrative approach is a potential first step to inform the correspondence between the neurocognitive and behavioral fields in youth addiction.

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Despite studies showing the relevance of different decision-making abilities, including response inhibition, to likelihood of using substances during adolescence, few have examined these neural processes among high-risk, substance-using youth. The current study explored associations between alcohol and marijuana use and functional activation differences during Stroop performance among a large sample (N=80) of ethnically-diverse, high-risk youth in an fMRI-based task. In the absence of associations between substance use and task behavioral performance, adolescents with greater alcohol use showed less activation during the more cognitively difficult portion of the task across clusters in bilateral cuneus and precuneus, and right and left superior temporal gyrus.

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Human adolescents engage in very high rates of unprotected sex. This behavior has a high potential for unintended, serious, and sustained health consequences including HIV/AIDS. Despite these serious health consequences, we know little about the neural and cognitive factors that influence adolescents' decision-making around sex, and their potential overlap with behaviorally co-occurring risk behaviors, including alcohol use.

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This research evaluates the impact of social norms on the advancement through the bystander stages toward prosocial (active) intervention in interpersonal violence (IPV): emotional abuse, physical violence, controlling behavior, sexual violence, and stalking. The influence of social norms on bystander behavior across stages and types of violence varies. Accurate social norms perceptions are associated with routine intervention, although social norms misperceptions are not always a strong deterrent to intervention.

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Recent research has suggested that marijuana use is associated with volumetric and shape differences in subcortical structures, including the nucleus accumbens and amygdala, in a dose-dependent fashion. Replication of such results in well controlled studies is essential to clarify the effects of marijuana. To that end, this retrospective study examined brain morphology in a sample of adult daily marijuana users (n = 29) versus nonusers (n = 29) and a sample of adolescent daily users (n = 50) versus nonusers (n = 50).

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