31 research outputs found

    Imbibition in Disordered Media

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    The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.Comment: Review article, to appear in Advances in Physics, 53 pages LaTe

    Relevance of Stress and Female Sex Hormones for Emotion and Cognition

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    There are clear sex differences in incidence and onset of stress-related and other psychiatric disorders in humans. Yet, rodent models for psychiatric disorders are predominantly based on male animals. The strongest argument for not using female rodents is their estrous cycle and the fluctuating sex hormones per phase which multiplies the number of animals to be tested. Here, we will discuss studies focused on sex differences in emotionality and cognitive abilities in experimental conditions with and without stress. First, female sex hormones such as estrogens and progesterone affect emotions and cognition, contributing to sex differences in behavior. Second, females respond differently to stress than males which might be related to the phase of the estrous cycle. For example, female rats and mice express less anxiety than males in a novel environment. Proestrus females are less anxious than females in the other estrous phases. Third, males perform in spatial tasks superior to females. However, while stress impairs spatial memory in males, females improve their spatial abilities, depending on the task and kind of stressor. We conclude that the differences in emotion, cognition and responses to stress between males and females over the different phases of the estrous cycle should be used in animal models for stress-related psychiatric disorders

    Trends in Mesothelioma Mortality in the United States Between 1999 and 2020

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    Introduction: Mesothelioma is a rare but aggressive cancer primarily caused by asbestos exposure. In March 2024, the Environmental Protection Agency banned asbestos in the United States, but its use will take years to phase out. Therefore, asbestos remains a threat, and incidence may remain stable or slowly decrease due to the long latency between exposure and diagnosis. This study investigates mesothelioma mortality trends in the United States from 1999 to 2020, focusing on demographic and geographic variations. Methods: Data on mesothelioma-related deaths from 1999 to 2020 were extracted from the Centers for Disease Control and Prevention database. Variables including race/ethnicity, sex, geographic density, and mesothelioma subtype were assessed. Age-adjusted mortality rates were calculated per 1 million individuals and standardized to the 2000 United States population. Joinpoint regression identified statistically significant changes in mortality trends over time. Results: From 1999 to 2020, there were 54,905 mesothelioma-related deaths in the United States (age-adjusted mortality rate = 7.5). Pleural mesothelioma accounted for 8.1% of deaths, peritoneal for 4.6%, pericardial for 0.01%, other sites for 10.9%, and unspecified sites for 76.3%. Most deaths (81.3%) occurred in individuals aged over 65 years. Overall mortality decreased from 8.5 in 1999 to 5.7 in 2020 at −1.9% annually. Non-Hispanic Whites had the highest mortality, and male individuals experienced higher mortality than female individuals. Suburban and rural populations had the highest mortality rates. Conclusions: The study highlights significant declines in mesothelioma mortality in the United States from 1999 to 2020, with variations across demographic and geographic groups. Continued monitoring and targeted interventions are necessary to address disparities and further reduce mesothelioma mortality

    Progesterone Treatment Shows Benefit in a Pediatric Model of Moderate to Severe Bilateral Brain Injury

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    PURPOSE: Controlled cortical impact (CCI) models in adult and aged Sprague-Dawley (SD) rats have been used extensively to study medial prefrontal cortex (mPFC) injury and the effects of post-injury progesterone treatment, but the hormone's effects after traumatic brain injury (TBI) in juvenile animals have not been determined. In the present proof-of-concept study we investigated whether progesterone had neuroprotective effects in a pediatric model of moderate to severe bilateral brain injury. METHODS: Twenty-eight-day old (PND 28) male Sprague Dawley rats received sham (n = 24) or CCI (n = 47) injury and were given progesterone (4, 8, or 16 mg/kg per 100 g body weight) or vehicle injections on post-injury days (PID) 1–7, subjected to behavioral testing from PID 9–27, and analyzed for lesion size at PID 28. RESULTS: The 8 and 16 mg/kg doses of progesterone were observed to be most beneficial in reducing the effect of CCI on lesion size and behavior in PND 28 male SD rats. CONCLUSION: Our findings suggest that a midline CCI injury to the frontal cortex will reliably produce a moderate TBI comparable to what is seen in the adult male rat and that progesterone can ameliorate the injury-induced deficits
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