Drexel University

About: Drexel University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 26770 authors who have published 51438 publications receiving 1949443 citations. The organization is also known as: Drexel & Drexel Institute.

Missing Link Found? The "Runaway" Path to Supermassive Black Holes

Abstract: Observations of stellar kinematics, gasdynamics, and masers around galactic nuclei have now firmly established that many galaxies host central supermassive black holes (SMBHs) with masses in the range of ~106-109 M☉. However, how these SMBHs formed is not well understood. One reason for this situation is the lack of observations of intermediate-mass BHs (IMBHs), which could bridge the gap between stellar mass BHs and SMBHs. Recently, this missing link (i.e., an IMBH) has been found in observations made by ASCA and Chandra of the central region of the starburst galaxy M82. Subsequent observations by Subaru have revealed that this IMBH apparently coincides with a young compact star cluster. Based on these findings, we suggest a new formation scenario for SMBHs. In this scenario, IMBHs first form in young compact star clusters through runaway merging of massive stars. While these IMBHs are forming, the host star clusters sink toward the galactic nucleus through dynamical friction and upon evaporation deposit their IMBHs near the galactic center. The IMBHs then form binaries and eventually merge via gravitational radiation, forming an SMBH.

The Locus Coeruleus as a Site for Integrating Corticotropin-Releasing Factor and Noradrenergic Mediation of Stress Responses

Abstract: Anatomic and electrophysiologic studies have provided evidence that CRF meets some of the criteria as a neurotransmitter in the noradrenergic nucleus, the locus coeruleus (LC), although some of the criteria have yet to be satisfied. Thus, immunohistochemical findings suggest that CRF innervates the LC, but this must be confirmed at the ultrastructural level. CRF alters discharge activity of LC neurons and these effects are mimicked by some stressors. Moreover, the effects of hemodynamic stress on LC activity are prevented by a CRF antagonist. However, it has not been demonstrated that stimulation of CRF neurons that project to the LC activates the LC or that the effects of such stimulation are prevented by a CRF antagonist. The role of CRF in LC activation by stressors other than hemodynamic stress needs to be determined. It could be predicted that the effects of CRF neurotransmission in the LC during stress would enhance information processing concerning the stressor or stimuli related to the stressor by LC target neurons. One consequence of this appears to be increased arousal. Although this may be adaptive in the response to an acute challenge, it could be predicted that chronic CRF release in the LC would result in persistently elevated LC discharge and norepinephrine release in targets. This could be associated with hyperarousal and loss of selective attention as occurs in certain psychiatric diseases. Manipulation of endogenous CRF systems may be a novel way in which to treat psychiatric diseases characterized by these maladaptive effects.

Asymmetric Flexible MXene-Reduced Graphene Oxide Micro-Supercapacitor

Abstract: The authors acknowledge Kathleen Maleski for designing the mask structure with AutoCAD and Bilen Akuzum for laser cutting of Kapton sheets. The authors also acknowledge Leah Clark for the schematic design. Material synthesis and electrochemical characterization work of M.A. and K.L.V.A. were funded by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Research reported in this publication was partially supported by King Abdullah University of Science and Technology (KAUST). C.C. was supported by the Erasmus Mundus joint master program, Materials for Energy Storage and Conversion (M.E.S.C.). A.M.N-S. was supported by CIC energiGUNE, the Basque Government Scholarship for predoctoral formation (PRE_2015_2_0096) and the Egonlabur Traveling Grant (EP_2016_1_0030). XRD and SEM were performed at the Centralized Research Facilities (CRF) at Drexel University.