193 research outputs found
Management of older adults with dementia who present to emergency services with neuropsychiatric symptoms
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139936/1/gps4599.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139936/2/gps4599_am.pd
Protoplanetary Disks in Ophiuchus as Seen From ALMA
We present a high angular resolution (), high
sensitivity ( mJy) survey of the 870 m continuum emission
from the circumstellar material around 49 pre-main sequence stars in the
Ophiuchus molecular cloud. Because most millimeter instruments have resided in
the northern hemisphere, this represents the largest high-resolution,
millimeter-wave survey of the circumstellar disk content of this cloud. Our
survey of 49 systems comprises 63 stars; we detect disks associated with 29
single sources, 11 binaries, 3 triple systems and 4 transition disks. We
present flux and radius distributions for these systems; in particular, this is
the first presentation of a reasonably complete probability distribution of
disk radii at millimeter-wavelengths. We also compare the flux distribution of
these protoplanetary disks with that of the disk population of the
Taurus-Auriga molecular cloud. We find that disks in binaries are both
significantly smaller and have much less flux than their counterparts around
isolated stars. We compute truncation calculations on our binary sources and
find that these disks are too small to have been affected by tidal truncation
and posit some explanations for this. Lastly, our survey found 3 candidate
gapped disks, one of which is a newly identified transition disk with no
signature of a dip in infrared excess in extant observations.Comment: 26 pages, 16 figures. Accepted for publication in Ap
A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks
We present a CARMA 1.3 mm continuum survey toward 9 Class 0 protostars in the
Perseus molecular cloud at 0.3 (70 AU) resolution. This
study approximately doubles the number of Class 0 protostars observed with
spatial resolutions 100 AU at millimeter wavelengths, enabling the presence
of protostellar disks and proto-binary systems to be probed. We detect
flattened structures with radii 100 AU around 2 sources (L1448 IRS2 and
Per-emb-14) and these sources may be strong disk candidates.
Marginally-resolved structures with position angles within 30 of
perpendicular to the outflow are found toward 3 protostars (L1448 IRS3C, IRAS
03282+3035, and L1448C) and are considered disk candidates. Two others (L1448
IRS3B and IRAS 03292+3039) have resolved structure, possibly indicative of
massive inner envelopes or disks; L1448 IRS3B also has a companion separated by
0.9 (210 AU). IC348-MMS does not have well-resolved
structure and the candidate first hydrostatic core L1451-MMS is marginally
resolved on 1 scales. The strong disk candidate sources were
followed-up with CO () observations, detecting velocity
gradients consistent with rotation, but it is unclear if the rotation is
Keplerian. We compare the observed visibility amplitudes to radiative transfer
models, finding that visibility amplitude ratios suggest a compact component
(possibly a disk) is necessary for 5 of 9 Class 0 sources; envelopes alone may
explain the other 4 systems. We conclude that there is evidence for the
formation of large disks in the Class 0 phase with a range of radii and masses
dependent upon their initial formation conditions.Comment: Accepted to ApJ, 58 pages, 19 Figures, 5 Table
With a little help from my friends?: Racial and gender differences in the role of social support in later-life depression medication adherence
Background: Social support has been shown to be an important factor in improving depression symptom outcomes, yet less is known regarding its impact on antidepressant medication adherence. This study sought to evaluate the role of perceived social support on adherence to new antidepressant medication prescriptions in later-life depression.
Methods: Data from two prospective observational studies of participants ≥60 years old, diagnosed with depression, and recently prescribed a new antidepressant (N = 452). Perceived social support was measured using a subscale of the Duke Social Support Index and medication adherence was assessed using a validated self-report measure.
Results: At four-month follow up, 68% of patients reported that they were adherent to antidepressant medication. Examining the overall sample, logistic regression analysis demonstrated no significant relationship between perceived social support and medication adherence. However, when stratifying the sample by social support, race, and gender, adherence significantly differed by race and gender in those with inadequate social support: Among those with low social support, African-American females were significantly less likely to adhere to depression treatment than white females (OR = 4.82, 95% CI = 1.14–20.28, p = 0.032) and white males (OR = 3.50, 95% CI = 1.03–11.92, p = 0.045).
Conclusions: There is a significant difference in antidepressant medication adherence by race and gender in those with inadequate social support. Tailored treatment interventions for low social support should be sensitive to racial and gender differences.The National Institute of Mental Health (5R21MH073002)Veterans Affairs Health Services Research & Development (IIR 04-104-2)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152350/1/Gerlach Kavanagh Watkins Chiang Kim Kales 2017 with_a_little_help_from_my_friends_racial_and_gender_differences_in_the_role_of_social_support_in_laterlife_depression_medicat.pd
First direct observation of a nearly ideal graphene band structure
Angle-resolved photoemission and X-ray diffraction experiments show that
multilayer epitaxial graphene grown on the SiC(000-1) surface is a new form of
carbon that is composed of effectively isolated graphene sheets. The unique
rotational stacking of these films cause adjacent graphene layers to
electronically decouple leading to a set of nearly independent linearly
dispersing bands (Dirac cones) at the graphene K-point. Each cone corresponds
to an individual macro-scale graphene sheet in a multilayer stack where
AB-stacked sheets can be considered as low density faults.Comment: 5 pages, 4 figure
Complex Structure in Class 0 Protostellar Envelopes III: Velocity Gradients in Non-Axisymmetric Envelopes, Infall or Rotation?
We present an interferometric kinematic study of morphologically complex
protostellar envelopes based on observations of the dense gas tracers N2H+ and
NH3. The strong asymmetric nature of most envelopes in our sample leads us to
question the common interpretation of velocity gradients as rotation, given the
possibility of projection effects in the observed velocities. Several
"idealized" sources with well-ordered velocity fields and envelope structures
are now analyzed in more detail. We compare the interferometric data to
position-velocity diagrams of kinematic models for spherical rotating collapse
and filamentary rotating collapse. For this purpose, we developed a filamentary
parametrization of the rotating collapse model to explore the effects of
geometric projection on the observed velocity structures. We find that most
envelopes in our sample have PV structures that can be reproduced by an
infalling filamentary envelope projected at different angles within the plane
of the sky. The infalling filament produces velocity shifts across the envelope
that can mimic rotation, especially when viewed at single-dish resolutions and
the axisymmetric rotating collapse model does not uniquely describe any
dataset. Furthermore, if the velocities are assumed to reflect rotation, then
the inferred centrifugal radii are quite large in most cases, indicating
significant fragmentation potential or more likely another component to the
line-center velocity. We conclude that ordered velocity gradients cannot be
interpreted as rotation alone when envelopes are non-axisymmetric and that
projected infall velocities likely dominate the velocity field on scales larger
than 1000 AU.Comment: 37 pages, 15 Figures, 2 Tables, Accepted to Ap
Clinical Follow‐up of Parkinson’s Disease With Newly Prescribed Quetiapine
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162820/2/mds28193_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162820/1/mds28193.pd
Predicting Risk of Potentially Preventable Hospitalization in Older Adults with Dementia
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151826/1/jgs16030_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151826/2/jgs16030.pd
Genome-wide screen reveals Rab12 GTPase as a critical activator of Parkinson's disease-linked LRRK2 kinase
Activating mutations in the Leucine Rich Repeat Kinase 2 (LRRK2) cause Parkinson's disease. LRRK2 phosphorylates a subset of Rab GTPases, particularly Rab10 and Rab8A, and we showed previously that these phosphoRabs play an important role in LRRK2 membrane recruitment and activation (Vides et al., 2022). To learn more about LRRK2 pathway regulation, we carried out an unbiased, CRISPR-based genome-wide screen to identify modifiers of cellular phosphoRab10 levels. A flow cytometry assay was developed to detect changes in phosphoRab10 levels in pools of mouse NIH-3T3 cells harboring unique CRISPR guide sequences. Multiple negative and positive regulators were identified; surprisingly, knockout of the Rab12 gene was especially effective in decreasing phosphoRab10 levels in multiple cell types and knockout mouse tissues. Rab-driven increases in phosphoRab10 were specific for Rab12, LRRK2 dependent and PPM1H phosphatase reversible, and did not require Rab12 phosphorylation; they were seen with wild type and pathogenic G2019S and R1441C LRRK2. As expected for a protein that regulates LRRK2 activity, Rab12 also influenced primary cilia formation. Alphafold modeling revealed a novel Rab12 binding site in the LRRK2 Armadillo domain and we show that residues predicted to be essential for Rab12 interaction at this site influence phosphoRab10 and phosphoRab12 levels in a manner distinct from Rab29 activation of LRRK2. Our data show that Rab12 binding to a new site in the LRRK2 Armadillo domain activates LRRK2 kinase for Rab phosphorylation and could serve as a new therapeutic target for a novel class of LRRK2 inhibitors that do not target the kinase domain.</p
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