233 research outputs found
Modifiable arousal in ADHD and its etiological association with fluctuating reaction times
BACKGROUND: Cognitive theories of attention-deficit/hyperactivity disorder (ADHD) propose that high within-subject fluctuations of cognitive performance in ADHD, particularly reaction time (RT) variability (RTV), may reflect arousal dysregulation. Yet, direct evidence of arousal dysregulation and how it may account for fluctuating reaction times in ADHD is limited. We used skin conductance (SC) as a measure of peripheral arousal and aimed to investigate its phenotypic and familial association with RTV in a large sample of ADHD and control sibling pairs.
METHODS: 292 adolescents and young adults, consisting of 73 participants with ADHD and their 75 siblings, as well as 72 controls and their 72 siblings, completed the baseline (slow, unrewarded) and fast-incentive conditions of a RT task, whilst SC was simultaneously recorded.
RESULTS: A significant group by condition interaction emerged for SC level (SCL). Participants with ADHD had decreased SCL, compared to controls, in the baseline but not fast-incentive condition. Baseline SCL was negatively associated with RTV and multivariate model fitting demonstrated that the covariance of SCL with RTV, and of SCL with ADHD, was mostly explained by shared familial effects.
CPNCLUSIONS: ADHD is associated with decreased, but modifiable, tonic peripheral arousal. A shared familial etiology underlies the relationship between arousal and RTV, and between arousal and ADHD. Given the malleability of SCL, if our findings are replicated, it warrants further exploration as a potential treatment target for ADHD
Synthesis and Characterization of Temperature-Sensitive and Chemically Cross-Linked Poly(N-isopropylacrylamide)/Photosensitizer Hydrogels for Applications in Photodynamic Therapy
Copyright © 2018 American Chemical Society. A novel poly(N-isopropylacrylamide) (PNIPAM) hydrogel containing different photosensitizers (protoporphyrin IX (PpIX), pheophorbide a (Pba), and protoporphyrin IX dimethyl ester (PpIX-DME)) has been synthesized with a significant improvement in water solubility and potential for PDT applications compared to the individual photosensitizers (PSs). Conjugation of PpIX, Pba, and PpIX-DME to the poly(N-isopropylacrylamide) chain was achieved using the dispersion polymerization method. This study describes how the use of nanohydrogel structures to deliver a photosensitizer with low water solubility and high aggregation tendencies in polar solvents overcomes these limitations. FT-IR spectroscopy, UV-vis spectroscopy, 1 H NMR, fluorescence spectroscopy, SEM, and DLS analysis were used to characterize the PNIPAM-photosensitizer nanohydrogels. Spectroscopic studies indicate that the PpIX, Pba, and PpIX-DME photosensitizers are covalently conjugated to the polymer chains, which prevents aggregation and thus allows significant singlet oxygen production upon illumination. Likewise, the lower critical solution temperature was raised to ∼44 °C in the new PNIPAM-PS hydrogels. The PNIPAM hydrogels are biocompatible with > 90% cell viability even at high concentrations of the photosensitizer in vitro. Furthermore, a very sharp onset of light-dependent toxicity for the PpIX-based nanohydrogel in the nanomolar range and a more modest, but significant, photocytotoxic response for Pba-PNIPAM and PpIX-DME-PNIPAM nanohydrogels suggest that the new hydrogels have potential for applications in photodynamic therapy
The glycolytic enzyme phosphofructokinase-1 assembles into filaments.
Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments. Negative-stain electron micrographs reveal that filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer. Electron micrographs and biochemical data with a PFKL/PFKP chimera indicate that the PFKL regulatory domain mediates filament assembly. Quantified live-cell imaging shows dynamic properties of localized PFKL puncta that are enriched at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform-specific glucose metabolism in cells
Comparing Galaxy Morphology at Ultraviolet and Optical Wavelengths
We have undertaken an imaging survey of 34 nearby galaxies in far-ultraviolet
(FUV, ~1500A) and optical (UBVRI) passbands to characterize galaxy morphology
as a function of wavelength. This sample, which includes a range of classical
Hubble types from elliptical to irregular with emphasis on spirals at low
inclination angle, provides a valuable database for comparison with images of
high-z galaxies whose FUV light is redshifted into the optical and near-
infrared bands. Ultraviolet data are from the UIT Astro-2 mission. We present
images and surface brightness profiles for each galaxy, and we discuss the
wavelength-dependence of morphology for different Hubble types in the context
of understanding high-z objects. In general, the dominance of young stars in
the FUV produces the patchy appearance of a morphological type later than that
inferred from optical images. Prominent rings and circumnuclear star formation
regions are clearly evident in FUV images of spirals, while bulges, bars, and
old, red stellar disks are faint to invisible at these short wavelengths.
However, the magnitude of the change in apparent morphology ranges from
dramatic in early--type spirals with prominent optical bulges to slight in
late-type spirals and irregulars, in which young stars dominate both the UV and
optical emission. Starburst galaxies with centrally concentrated, symmetric
bursts display an apparent ``E/S0'' structure in the FUV, while starbursts
associated with rings or mergers produce a peculiar morphology. We briefly
discuss the inadequacy of the optically-defined Hubble sequence to describe FUV
galaxy images and estimate morphological k-corrections, and we suggest some
directions for future research with this dataset.Comment: Accepted for publication in the ApJS. 15 pages, 17 JPEG figures, 10
GIF figures. Paper and full resolution figures available at
http://nedwww.ipac.caltech.edu/level5/Kuchinski/frames.htm
Occult purulent pericarditis detected by indium-111 leukocyte imaging.
Leukocyte imaging with indium-111 is a relatively new technique which, to this point in time, has been discussed almost exclusively in the radiologic literature. Although this procedure has been used mainly to detect intra-abdominal infection, the thorax is routinely imaged along with the abdomen, and therefore detection of cardiac disease may be feasible. This case report is of a young woman after liver transplantation who developed occult purulent pericarditis initially detected by a leukocyte scan with indium-111. This case demonstrates that striking pericardial uptake on a whole-body indium-111 leukocyte scan can occur with purulent pericarditis, and it reemphasizes how insidiously purulent pericarditis may present in an immunosuppressed patient
Ultraviolet Signposts of Resonant Dynamics in the Starburst-Ringed Sab Galaxy, M94 (NGC 4736)
M94 (NGC 4736) is investigated using images from the Ultraviolet Imaging
Telescope (FUV-band), Hubble Space Telescope (NUV-band), Kitt Peak 0.9-m
telescope (H-alpha, R, and I bands), and Palomar 5-m telescope (B-band), along
with spectra from the International Ultraviolet Explorer and Lick 1-m
telescopes. The wide-field UIT image shows FUV emission from (a) an elongated
nucleus, (b) a diffuse inner disk, where H-alpha is observed in absorption, (c)
a bright inner ring of H II regions at the perimeter of the inner disk (R = 48
arcsec. = 1.1 kpc), and (d) two 500-pc size knots of hot stars exterior to the
ring on diametrically opposite sides of the nucleus (R= 130 arcsec. = 2.9 kpc).
The HST/FOC image resolves the NUV emission from the nuclear region into a
bright core and a faint 20 arcsec. long ``mini-bar'' at a position angle of 30
deg. Optical and IUE spectroscopy of the nucleus and diffuse inner disk
indicates an approximately 10^7 or 10^8 yr-old stellar population from
low-level starbirth activity blended with some LINER activity. Analysis of the
H-alpha, FUV, NUV, B, R, and I-band emission along with other observed tracers
of stars and gas in M94 indicates that most of the star formation is being
orchestrated via ring-bar dynamics involving the nuclear mini-bar, inner ring,
oval disk, and outer ring. The inner starburst ring and bi-symmetric knots at
intermediate radius, in particular, argue for bar-mediated resonances as the
primary drivers of evolution in M94 at the present epoch. Similar processes may
be governing the evolution of the ``core-dominated'' galaxies that have been
observed at high redshift. The gravitationally-lensed ``Pretzel Galaxy''
(0024+1654) at a redshift of approximately 1.5 provides an important precedent
in this regard.Comment: revised figure 1 (corrected coordinate labels on declination axis);
19 pages of text + 19 figures (jpg files); accepted for publication in A
Obstacles to public health that even pandemics cannot overcome : the politics of Covid-19 on the island of Ireland
The relationship between politics and public health is increasingly evident as governments throughout the world vary in their acceptance and implementation of technical guidance in the response to the SARS-CoV-2 pandemic. This paper reports a qualitative study of public health policies for Covid-19 in Northern Ireland (NI) and the Republic of Ireland (RoI) across a timeline emphasising the first wave of the pandemic (February to June 2020). Inter-jurisdictional commitments for health as contained in the Good Friday Agreement provide a framework for cooperation and coordination of population health on the island of Ireland. This study of north-south cooperation in the response to Covid-19 applies ten indicators from the Oxford Covid-19 Government Response Tracker (OxCGRT) codebook to establish if cooperation and policy alignment of key public health measures are evident in the Northern Ireland Assembly and Government of Ireland responses. The study concludes that notwithstanding the historical and constitutional obstacles to an all-island response to Covid-19, there is evidence of significant public health policy alignment brought about through ongoing dialogue and cooperation between the health administrations in each jurisdiction over the course of the first wave of the pandemic
Genealogies of Slavery
This chapter addresses the concept of slavery, exploring its character and significance as a dark page in history, but also as a specifically criminological and zemiological problem, in the context of international law and human rights. By tracing the ambiguities of slavery in international law and international development, the harms associated with slavery are considered. Harms include both those statutorily proscribed, and those that are not, but that can still be regarded as socially destructive. Traditionally, antislavery has been considered within the parameters of abolition and criminalization. In this context recently, anti-trafficking has emerged as a key issue in contemporary anti-slavery work. While valuable, anti-trafficking is shown to have significant limitations. It advances criminalization and stigmatization of the most vulnerable and further perpetuates harm. At the same time, it identifies structural conditions like poverty, vulnerability, and “unfreedom” of movement only to put them aside. Linked to exploitation, violence and zemia, the chapter brings to the fore some crucial questions concerning the prospects of systemic theory in the investigation of slavery, that highlight the root causes of slavery, primarily poverty and inequality. Therefore, the chapter counterposes an alternative approach in which the orienting target is not abolition of slavery but advancing structural changes against social harm
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