31 research outputs found
Spectra of Hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory
Most Type I superluminous supernovae (SLSNe-I) reported to date have been identified by their high peak luminosities and spectra lacking obvious signs of hydrogen. We demonstrate that these events can be distinguished from normal-luminosity SNe (including Type Ic events) solely from their spectra over a wide range of light-curve phases. We use this distinction to select 19 SLSNe-I and four possible SLSNe-I from the Palomar Transient Factory archive (including seven previously published objects). We present 127 new spectra of these objects and combine these with 39 previously published spectra, and we use these to discuss the average spectral properties of SLSNe-I at different spectral phases. We find that Mn II most probably contributes to the ultraviolet spectral features after maximum light, and we give a detailed study of the O II features that often characterize the early-time optical spectra of SLSNe-I. We discuss the velocity distribution of O II, finding that for some SLSNe-I this can be confined to a narrow range compared to relatively large systematic velocity shifts. Mg II and Fe II favor higher velocities than O II and C II, and we briefly discuss how this may constrain power-source models. We tentatively group objects by how well they match either SN 2011ke or PTF12dam and discuss the possibility that physically distinct events may have been previously grouped together under the SLSN-I label
Immunological mechanism of action and clinical profile of disease-modifying treatments in multiple sclerosis.
Multiple sclerosis (MS) is a life-long, potentially debilitating disease of the central nervous system (CNS). MS is considered to be an immune-mediated disease, and the presence of autoreactive peripheral lymphocytes in CNS compartments is believed to be critical in the process of demyelination and tissue damage in MS. Although MS is not currently a curable disease, several disease-modifying therapies (DMTs) are now available, or are in development. These DMTs are all thought to primarily suppress autoimmune activity within the CNS. Each therapy has its own mechanism of action (MoA) and, as a consequence, each has a different efficacy and safety profile. Neurologists can now select therapies on a more individual, patient-tailored basis, with the aim of maximizing potential for long-term efficacy without interruptions in treatment. The MoA and clinical profile of MS therapies are important considerations when making that choice or when switching therapies due to suboptimal disease response. This article therefore reviews the known and putative immunological MoAs alongside a summary of the clinical profile of therapies approved for relapsing forms of MS, and those in late-stage development, based on published data from pivotal randomized, controlled trials
Hypothalamic neurons that mirror aggression
Social interactions require awareness and understanding of the behavior of others. Mirror neurons, cells representing an action by self and others, have been proposed to be integral to the cognitive substrates that enable such awareness and understanding. Mirror neurons of the primate neocortex represent skilled motor tasks, but it is unclear if they are critical for the actions they embody, enable social behaviors, or exist in non-cortical regions. We demonstrate that the activity of individual VMHvlPR neurons in the mouse hypothalamus represents aggression performed by self and others. We used a genetically encoded mirror-TRAP strategy to functionally interrogate these aggression-mirroring neurons. We find that their activity is essential for fighting and that forced activation of these cells triggers aggressive displays by mice, even toward their mirror image. Together, we have discovered a mirroring center in an evolutionarily ancient region that provides a subcortical cognitive substrate essential for a social behavior
Untargeted Metabolomics Analyses and Contaminant Chemistry of Dreissenid Mussels at the Maumee River Area of Concern in the Great Lakes
Bivalves serve as an ideal ecological indicator; hence,
their use
by the NOAA Mussel Watch Program to monitor environmental health.
This study aimed to expand the baseline knowledge of using metabolic
end points in environmental monitoring by investigating the dreissenid
mussel metabolome in the field. Dreissenids were caged at four locations
along the Maumee River for 30 days. The mussel metabolome was measured
using nuclear magnetic resonance spectroscopy, and mussel tissue chemical
contaminants were analyzed using gas or liquid chromatography coupled
with mass spectrometry. All Maumee River sites had a distinct mussel
metabolome compared to the reference site and revealed changes in
the energy metabolism and amino acids. Data also highlighted the importance
of considering seasonality or handling effects on the metabolome at
the time of sampling. The furthest upstream site presented a specific
mussel tissue chemical signature of pesticides (atrazine and metolachlor),
while a downstream site, located at Toledo’s wastewater treatment
plant, was characterized by polycyclic aromatic hydrocarbons and other
organic contaminants. Further research into the dreissenid mussel’s
natural metabolic cycle and metabolic response to specific anthropogenic
stressors is necessary before successful implementation of metabolomics
in a biomonitoring program