Kent State University

About: Kent State University is a education organization based out in Kent, Ohio, United States. It is known for research contribution in the topics: Liquid crystal & Population. The organization has 10897 authors who have published 24607 publications receiving 720309 citations. The organization is also known as: Kent State & KSU.

Midbrain Raphe Modulation of Nonphotic Circadian Clock Resetting and 5-HT Release in the Mammalian Suprachiasmatic Nucleus

Abstract: Serotonin (5-HT) is an important regulator of the mammalian circadian clock of the suprachiasmatic nucleus (SCN); however, critical questions remain concerning the control of serotonergic activity in the SCN and how this relates to the putative clock-resetting actions of 5-HT. Previously, we reported that electrical stimulation of the dorsal raphe nucleus (DRN) or median raphe nucleus (MRN) in hamsters evoked 5-HT release in the SCN. This DRN-stimulated 5-HT release was blocked by systemic injection of 5-HT antagonists, indicating a 5-HT receptor-mediated pathway from the DRN to the SCN. In the present study, targeted injections of the 5-HT 1,2,7 antagonist metergoline or the selective 5-HT 7 antagonist DR4004 into the DRN or MRN attenuated DRN-electrically stimulated SCN 5-HT release, supporting a multisynaptic DRN→MRN→SCN route. Intra-DRN and intra-MRN injections of the GABA A antagonist bicuculline significantly stimulated SCN 5-HT release, whereas intra-DRN or intra-MRN injections of the GABA A agonist muscimol suppressed this release. The 5-HT release induced by intra-DRN bicuculline was also blocked by co-injection of DR4004. In complementary behavioral trials, SCN 5-HT release associated with a phase-advancing sleep deprivation stimulus at midday was prevented by intra-DRN injection of metergoline. Also, phase-advance shifts induced by novel wheel access at midday were suppressed, but not blocked, by intra-DRN injection of DR4004 or muscimol. These results indicate that 5-HT 7 and GABAergic receptors of the DRN and MRN regulate behaviorally induced 5-HT release in the SCN, and that DRN output modulates nonphotic phase-resetting responses.

Self-assembly with postmodification: kinetically stabilized metalla-supramolecular rectangles.

Abstract: Interaction of a predesigned molecular “clip” (4) with rigid dipyridyl bridging ligands, in acetone/water mixtures, leads to the formation of molecular rectangles (5−8) in 92−97% isolated yields via spontaneous self-assembly. Characterization was accomplished with multinuclear NMR and UV−vis spectroscopy, FAB mass spectrometry, and X-ray crystallography. The length of these metallamacrocycles ranges from 2 to 3 nm. Postmodification via non-nucleophilic counterion exchange results in enhanced structural integrity for the assemblies.

Tender Violence: Domestic Visions in an Age of U.S. Imperialism

Abstract: Laura Wexler presents an incisive analysis of how the first American female photojournalists contributed to a "doctrine vision" that reinforced the imperialism and racism of America around the dawn of the 20th century. These women photographers, white and middle class, constructed images of war disguised as peace through a mechanism Wexler calls the "averted eye", which had its origins in the private domain of family photography. Wexler examines the work of Frances Benjamin Johnston, Gertrude Kasebier, Alice Austen, the Gerhard sisters and Jessie Tarbox Beals. The book includes over 150 photographs taken between 1898 and 1904, such as photos Johnston took aboard Admiral Dewey's flagship as it returned home from conquering Manila, Austen's photos of immigrants at Ellis Island, and Beal's images of the St Louis World's Fair of 1904. In a groundbreaking approach to the study of photography, Wexler raises up these images as "texts" to be analyzed alongside other texts of the period for what they say about the discourses of power. This study is relevant not only to the fields of history of photography and gender studies, but also to our growing understanding of US imperialism during this period.

A weighted-GCV method for Lanczos-hybrid regularization.

Abstract: Lanczos-hybrid regularization methods have been proposed as effective approaches for solving largescale ill-posed inverse problems. Lanczos methods restrict the solution to lie in a Krylov subspace, but they are hindered by semi-convergence behavior, in that the quality of the solution first increases and then decreases. Hybrid methods apply a standard regularization technique, such as Tikhonov regularization, to the projected problem at each iteration. Thus, regularization in hybrid methods is achieved both by Krylov filtering and by appropriate choice of a regularization parameter at each iteration. In this paper we describe a weighted generalized cross validation (WGCV) method for choosing the parameter. Using this method we demonstrate that the semi-convergence behavior of the Lanczos method can be overcome, making the solution less sensitive to the number of iterations.

Hyperarousal and sleep reactivity in insomnia: current insights

Abstract: Hyperarousal is a key component in all modern etiological models of insomnia disorder. Overall patterns in the literature suggest that over-active neurobiological and psychological systems contribute to difficulty sleeping. Even so, mixed results regarding the specific mechanisms linking hyperarousal to sleep disturbance limit current etiological conceptualizations. Similar basal arousal profiles between individuals with high vs low risk for insomnia in the absence of stress exposure suggest that dysregulated stress "response" rather than general hyperarousal may be a more pertinent marker of risk. In this report, we discuss evidence for hyperarousal in insomnia and explore the role of sleep reactivity. A trait characteristic, sleep reactivity is the degree to which stress disrupts sleep, manifesting as difficulty falling and staying asleep. Premorbid sleep reactivity has been shown to identify individuals at risk for future insomnia disorder, such as highly reactive sleepers (whose sleep systems are sensitive to stress) who are at elevated disease risk. Research points to genetics, family history of insomnia, gender, and environmental stress as factors that influence sleep reactivity. Importantly, stress-related cognitive-emotional reactivity (e.g., rumination, worry) may exploit the vulnerability of a highly reactive sleep system. We propose that sleep reactivity and cognitive-emotional reactivity may share a bidirectional relationship, conferring an insalubrious environment for sleep in response to stress. Future research on sleep reactivity is needed to identify its neurobiology, characterize its relationship with cognitive-emotional reactivity, and explore the potential clinical utility of sleep reactivity in treatment planning.