6,743 research outputs found
Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue
Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower
The structure of triphenylgermanium hydroxide
C18H~6GeO, Mr = 320.9, triclinic, Pi, a =
15.408 (6), b = 19.974 (7), c = 23.264 (11) A, a =
107.78 (4), 13 = 1.03.54 (4), y= 101.51 (3) °, V =
6338 (5)/~3, Z = 16, Dx = 1.34 g cm -3, a(Mo Ka) =
0.71073A, /z = 19.1cm-1, F(000)=2624, T=
293 K, R = 0.055 for 6846 observed reflections. The
eight independent molecules in the asymmetric unit
form two independent O--H...O hydrogen-bonded
tetramers with the O atoms in a flattened tetrahedral
arrangement [hydrogen-bond distances in the range
2.609 (11) to 2.657 (11)A]. The Ge atoms are tetrahedrally
coordinated with mean Gc O 1.791 (7) and
Gc C 1.931 (8) A
Twisted [(R3P)PdX] groups above dicarbaborane ligands: 4-dimethylsulfido-3-iodo-3-triphenylphosphine-closo-3-pallada-1,2-dicarbadodecaborane and 3-dimethylphenylphosphine-3-chloro-4-dimethylsulfido-closo-3-pallada-1,2-dicarbadodecaborane
The structural analyses of [3-(PPhâ)-3-I-4-(SMeâ)-closo-3,1,2-PdCâBâHââ] or [Pd(CâHââBâS)I(CââHââ
P)], (I), and [3-(PPhMeâ)-3-Cl-4-(SMeâ)-closo-3,1,2-PdCâBâHââ] or [Pd(CâHââBâS)Cl(CâHââP)], (II), show that in comparison with [3-(PRâ)2-closo-3,1,2-PdCâBâHââ] the presence of the 4-SMeâ group causes the [PdX(PRâ)] unit (X = halogen) to twist about an axis passing through the Pd atom and the directly opposite B atom of the carbaborane ligand. The halogen atoms are located almost directly above a C atom in the CâBâ face, and the conformations of the [PdX(PRâ)] units above the CâBâ faces are not those predicted from molecular orbital calculations of the closo-3,1,2-PdCâBâ system. The fact that the variation from the predicted conformation is greater in the case of (I) than in (II) may be ascribed to the greater steric interactions induced by the I atom in (I) compared with the Cl atom in (II)
[8,8-(PPh3)2-9-(OEt)-8,7-RhSB9H9].0.95(CH2Cl2)
9-Ethoxy-8,8-di(triphenylphosphine)-9,10-
tz H-8-rhoda-7-thia-nido-undecaborane( l O) dichloromethane
solvate, C38Ha4B9OP2RhS.0.95(CH2C12), Mr
= 891.7, triclinic, Pi, a = 10.271 (4), b = 11.401 (3), c
= 19.426 (4)/~, a = 74.86 (2), 13 = 88.51 (3), y =
83.51 (3) °, V= 2182 (2)/~3, Z= 2, Dx =
1.357 g cm-3, graphite-monochromated Mo Ka
radiation, a = 0.71073 A, /z = 6.5 cm-1, F(000) =
912, T= 294 K, R = 0.038 for 3984 observed reflections.
The title compound contains an l 1-atom
RhSB9 nido-structured cage with Rh and S atoms
adjacent in the open RhSB3 face. An ethoxy group is
bonded to the B atom adjacent to Rh in the open
face with Rh--B9 2.119 (6) and B9--O 1.387 (9)A.
The phosphine ligands are bonded to the Rh atom with one Rh--P bond [2.278 (2)A] trans to the S
atom and the other [2.417 (1) A] located perpendicular
to the open face of the cage
Structure of 1-(3-butynyl)pyridinium p-toluenesulfonate
The 1-(3-butynyl)pyridinium p-toluenesulfonate salt,
C9H10N+.CTHTO3S -, contains a C--H...O hydrogen
bond between the acetylenic H atom of the cation and a
sulfonate O atom of the anion in the solid state [C...O
3.32 (1), H...O 2.49 A, C--H...O 159°]. The X-ray analysis
was complicated by disorder in both the cation and
anion. A major (85%) and a minor (15%) component of
the 1-(3-butynyl)pyridinium cation are present, both occuping
the same volume element in the lattice. The methyl
H atoms and sulfonate O atoms of the p-toluenesulfonate
anion are disordered over two orientations
Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer
The Large Binocular Telescope Interferometer uses a near-infrared camera to
measure the optical path length variations between the two AO-corrected
apertures and provide high-angular resolution observations for all its science
channels (1.5-13 m). There is however a wavelength dependent component to
the atmospheric turbulence, which can introduce optical path length errors when
observing at a wavelength different from that of the fringe sensing camera.
Water vapor in particular is highly dispersive and its effect must be taken
into account for high-precision infrared interferometric observations as
described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this
paper, we describe the new sensing approach that has been developed at the LBT
to measure and monitor the optical path length fluctuations due to dry air and
water vapor separately. After reviewing the current performance of the system
for dry air seeing compensation, we present simultaneous H-, K-, and N-band
observations that illustrate the feasibility of our feedforward approach to
stabilize the path length fluctuations seen by the LBTI nuller.Comment: SPIE conference proceeding
How do you define recovery? A qualitative study of patients with eating disorders, their parents, and clinicians
ObjectiveRecovery from an eating disorder (ED) may be defined differently by different stakeholders. We set out to understand the definition of ED recovery from the perspective of patients, their parents, and clinicians.MethodWe recruited patients with EDs (n = 24, ages 12â23âyears) representing different diagnoses (anorexia nervosa n = 17, bulimia nervosa n = 4, bingeâED n = 2, avoidant/restrictive food intake disorder n = 1), along with their parents (n = 20), dietitians (n = 11), therapists (n = 14), and primary care providers (n = 9) from three sites: Boston Childrenâs Hospital, University of Michigan C. S. Mott Childrenâs Hospital, and Penn State Hershey Childrenâs Hospital. Inâdepth, semiâstructured, qualitative interviews explored participantsâ definitions of recovery. Interviews were analyzed using inductive dataâdriven thematic analysis. Statistical analyses followed to examine the distribution within each theme by respondent type.ResultsQualitative analysis resulted in the emergence of four overarching themes of ED recovery: (a) psychological wellâbeing, (b) eatingârelated behaviors/attitudes, (c) physical markers, and (d) selfâacceptance of body image. Endorsement of themes two and four did not significantly differ between patients, parents, and clinicians. Clinicians were significantly more likely to endorse theme one (Ď2 =â9.90, df =â2, p =â.007, Ďc =â0.356) and theme three (Ď2 =â6.42, df =â2, p =â.04, Ďc =â0.287) than patients and parents.DiscussionOur study demonstrates overwhelming support for psychological markers as indicators of ED recovery by all three groups. Clinicians should remain open to additional markers of recovery such as body acceptance and eatingârelated behaviors/emotions that may be of critical importance to patients and their caregivers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156211/2/eat23294_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156211/1/eat23294.pd
Exoplanet science with the LBTI: instrument status and plans
The Large Binocular Telescope Interferometer (LBTI) is a strategic instrument
of the LBT designed for high-sensitivity, high-contrast, and high-resolution
infrared (1.5-13 m) imaging of nearby planetary systems. To carry out a
wide range of high-spatial resolution observations, it can combine the two
AO-corrected 8.4-m apertures of the LBT in various ways including direct
(non-interferometric) imaging, coronagraphy (APP and AGPM), Fizeau imaging,
non-redundant aperture masking, and nulling interferometry. It also has
broadband, narrowband, and spectrally dispersed capabilities. In this paper, we
review the performance of these modes in terms of exoplanet science
capabilities and describe recent instrumental milestones such as first-light
Fizeau images (with the angular resolution of an equivalent 22.8-m telescope)
and deep interferometric nulling observations.Comment: 12 pages, 6 figures, Proc. SPI
Rotational dynamics and heating of trapped nanovaterite particles
We synthesize, optically trap, and rotate individual nanovaterite crystals with a mean particle radius of 423 nm. Rotation rates of up to 4.9 kHz in heavy water are recorded. Laser-induced heating due to residual absorption of the nanovaterite particle results in the superlinear behavior of the rotation rate as a function of trap power. A finite element method based on the Navier-Stokes model for the system allows us to determine the residual optical absorption coefficient for a trapped nanovaterite particle. This is further confirmed by the theoretical model. Our data show that the translational Stokes drag force and rotational Stokes drag torque need to be modified with appropriate correction factors to account for the power dissipated by the nanoparticle
Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.
New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus. This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease. In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day, whereas other studies find many fewer putative new neurons. Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal development. We also find that the number of proliferating progenitors and young neurons in the dentate gyrus declines sharply during the first year of life and only a few isolated young neurons are observed by 7 and 13 years of age. In adult patients with epilepsy and healthy adults (18-77 years; nâ=â17 post-mortem samples from controls; nâ=â12 surgical resection samples from patients with epilepsy), young neurons were not detected in the dentate gyrus. In the monkey (Macaca mulatta) hippocampus, proliferation of neurons in the subgranular zone was found in early postnatal life, but this diminished during juvenile development as neurogenesis decreased. We conclude that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans. The early decline in hippocampal neurogenesis raises questions about how the function of the dentate gyrus differs between humans and other species in which adult hippocampal neurogenesis is preserved
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