2,901 research outputs found
Characterisation of the first authenticated organomercury hydroxide, 4-MeāNCāHāHgOH
4-MeāNCāHāHgOH was prepared from 4-MeāNCāHāHgOAc. Full characterisation showed that it crystallises as discrete molecules, the first example of a true organomercury hydroxide in the solid state. The structures of 4-MeāNCāHāHgOAc and (4-MeāNCāHā)āHg are also discussed.
4-MeāNCāHāHgOH has been characterised spectroscopically and crystallographically as a true organomercury hydroxide
Large-scale atomistic density functional theory calculations of phosphorus-doped silicon quantum bits
We present density functional theory calculations of phosphorus dopants in
bulk silicon and of several properties relating to their use as spin qubits for
quantum computation. Rather than a mixed pseudopotential or a Heitler-London
approach, we have used an explicit treatment for the phosphorus donor and
examined the detailed electronic structure of the system as a function of the
isotropic doping fraction, including lattice relaxation due to the presence of
the impurity. Doping electron densities and spin densities are examined in
order to study the properties of the dopant electron as a function of the
isotropic doping fraction. Doping potentials are also calculated for use in
calculations of the scattering cross-sections of the phosphorus dopants, which
are important in the understanding of electrically detected magnetic resonance
experiments. We find that the electron density around the dopant leads to
non-spherical features in the doping potentials, such as trigonal lobes in the
(001) plane at energy scales of +12 eV near the nucleus and of -700 meV
extending away from the dopants. These features are generally neglected in
effective mass theory and will affect the coupling between the donor electron
and the phosphorus nucleus. Our density functional calculations reveal detail
in the densities and potentials of the dopants which are not evident in
calculations that do not include explicit treatment of the phosphorus donor
atom and relaxation of the crystal lattice. These details can also be used to
parameterize tight-binding models for simulation of large-scale devices.Comment: 22 pages, 8 figure
Structure and energetics of helium adsorption on nanosurfaces
The ground and excited state properties of small helium clusters, 4He_N,
containing nanoscale (~3-10 Angstroms) planar aromatic molecules have been
studied with quantum Monte Carlo methods. Ground state structures and energies
are obtained from importance-sampled, rigid-body diffusion Monte Carlo. Excited
state energies due to helium vibrational motion are evaluated using the
projection operator, imaginary time spectral evolution technique. We examine
the adsorption of N helium atoms (N less than or equal to 24) on a series of
planar aromatic molecules (benzene, naphthalene, anthracene, tetracene,
phthalocyanine). The first layer of helium atoms is well-localized on the
molecule surface, and we find well-defined localized excitations due to
in-plane vibrational motion of helium on the molecule surface. We discuss the
implications of these confined excitations for the molecule spectroscopy.Comment: 6 pages, 2 figures, QFS 2003 Symposium, submitted to J. Low Temp.
Phy
Socio-Emotional Development in Children with Autism Spectrum Disorder
The purpose of the present study was to determine which lesson from a social skills program would result in the greatest improvement in duration of social interaction for children with a diagnosis of Autism Spectrum Disorder (ASD) between the ages of five and fifteen. The Superheroes Social Skills Program (Jensen et al., 2011) includes lesson plans that focus directly on helping children with ASD develop communication skills in group settings. The data indicate that one specific lesson, Participation and Joining In, was responsible for the largest mean increase in duration of social interactions of participants. Social skills lessons were introduced in different orders for each participant. This is significant, because we were able to determine that the social skills lesson on Participating and Joining In is successful regardless of when it is introduced in relation to other lessons, suggesting that it is independently effective and may not require other foundational skills to improve duration of social interaction
From the Ground Up
Mining had an enormous role, only partly measurable, in the history of Utah. Its multidimensional impact continues today. Economically, it made a major long-term contribution to the wealth, employment, and tax base of the state and stimulated a seemingly endless range of secondary businesses and enterprises. It helped shape the state\u27s social history, determining the location, distribution, and composition of many communities and bringing transportation systems and a wide variety of institutions to them. It developed cultural diversity by drawing to Utah miners and families from otherwise underrepresented ethnic and national backgrounds. It ignited strife, particularly between labor and management, but those issues often spread into or connected with other conflicts in and between communities, classes, and factions. It influenced political platforms, generated candidates, and helped decide elections. Throughout the state, mining dramatically transformed the landscape, most obviously at what has been called the world\u27s largest open-pit mine, which removed much of a mountain on the west side of Salt Lake Valley, but at innumerable other places too. Despite all mining has done and meant, there has not been, until now, a book that surveyed its history in Utah. From the Ground Up fills that gap in a collection of essays by leading experts, among them historians Thomas G. Alexander, Martha Sonntag Bradley-Evans, James E. Fell Jr., Laurence P. James, Brigham D. Madsen, Philip F. Notarianni, Allen Kent Powell, W. Paul Reeve, Raye C. Ringholz, and Janet Burton Seegmiller and geologists J. Wallace Gwynn and William T. Parry. The book is divided into three comprehensive parts. The first looks at The Ground of Utah Mining : the geology that has produced extractable minerals, the economic history of the industry, father of Utah mining Patrick E. Connor, and the lore of mines and miners. Part II reviews the history of a handful of particularly significant mineral industries: salines, coal, uranium, and beryllium. The last part takes a region-by-region approach to survey the important, primarily for hard-rock mining, areas of the state, including places from Silver Reef to Alta, the East Tintic Range to the Uinta Basin, and Park City to Frisco.https://digitalcommons.usu.edu/usupress_pubs/1111/thumbnail.jp
Shock-Driven Periodic Variability in a Low-Mass-Ratio Supermassive Black Hole Binary
We investigate the time-varying electromagnetic emission of a low-mass-ratio
supermassive black hole binary (SMBHB) embedded in a circumprimary disk, with a
particular interest in variability of shocks driven by the binary. We perform a
2D, locally isothermal hydrodynamics simulation of a SMBHB with mass ratio
and separation , using a physically self-consistent steady
disk model. We estimate the electromagnetic variability from the system by
monitoring accretion onto the secondary and using an artificial viscosity
scheme to capture shocks and monitor the energy dissipated. The SMBHB produces
a wide, eccentric gap in the disk, previously only observed for larger mass
ratios, which we attribute to our disk model being much thinner
( near the secondary) than is typical of previous works. The
eccentric gap drives periodic accretion onto the secondary SMBH on a timescale
matching the orbital period of the binary, ,
implying that the variable accretion regime of the SMBHB parameter space
extends to lower mass ratios than previously established. Shocks driven by the
binary are periodic, with a period matching the orbital period, and the shocks
are correlated with the accretion rate, with peaks in the shock luminosity
lagging peaks in the accretion rate by . We propose that
the correlation of these quantities represents a useful identifier of SMBHB
candidates, via observations of correlated variability in X-ray and UV
monitoring of AGN, rather than single-waveband periodicity alone.Comment: 12 pages, 8 figures, accepted by MNRA
Midazolam Efficacy Against Acute Hydrogen Sulfide-Induced Mortality and Neurotoxicity.
Hydrogen sulfide (H2S) is a colorless, highly neurotoxic gas. It is not only an occupational and environmental hazard but also of concern to the Department of Homeland Security for potential nefarious use. Acute high-dose H2S exposure causes death, while survivors may develop neurological sequelae. Currently, there is no suitable antidote for treatment of acute H2S-induced neurotoxicity. Midazolam (MDZ), an anti-convulsant drug recommended for treatment of nerve agent intoxications, could also be of value in treating acute H2S intoxication. In this study, we tested the hypothesis that MDZ is effective in preventing/treating acute H2S-induced neurotoxicity. This proof-of-concept study had two objectives: to determine whether MDZ prevents/reduces H2S-induced mortality and to test whether MDZ prevents H2S-induced neurological sequelae. MDZ (4Ā mg/kg) was administered IM in mice, 5Ā min pre-exposure to a high concentration of H2S at 1000Ā ppm or 12Ā min post-exposure to 1000Ā ppm H2S followed by 30Ā min of continuous exposure. A separate experiment tested whether MDZ pre-treatment prevented neurological sequelae. Endpoints monitored included assessment of clinical signs, mortality, behavioral changes, and brain histopathological changes. MDZ significantly reduced H2S-induced lethality, seizures, knockdown, and behavioral deficits (pĀ <Ā 0.01). MDZ also significantly prevented H2S-induced neurological sequelae, including weight loss, behavior deficits, neuroinflammation, and histopathologic lesions (pĀ <Ā 0.01). Overall, our findings show that MDZ is a promising drug for reducing H2S-induced acute mortality, neurotoxicity, and neurological sequelae
Space Station Freedom environmental control and life support system phase 3 simplified integrated test detailed report
A description of the phase 3 simplified integrated test (SIT) conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) in 1989 is presented. This was the first test in the phase 3 series integrated environmental control and life support systems (ECLSS) tests. The basic goal of the SIT was to achieve full integration of the baseline air revitalization (AR) subsystems for Space Station Freedom. Included is a description of the SIT configuration, a performance analysis of each subsystem, results from air and water sampling, and a discussion of lessons learned from the test. Also included is a full description of the preprototype ECLSS hardware used in the test
Pilot study of the safety and effect of adalimumab on pain, physical function, and musculoskeletal disease in mucopolysaccharidosis types I and II.
Mucopolysaccharidosis I and II are lysosomal storage disorders that, despite treatment with hematopoietic cell transplantation (HCT) and/or enzyme replacement therapy (ERT), continue to cause significant skeletal abnormalities leading to pain, stiffness, physical dysfunction, and short stature. Tumor necrosis factor - alpha (TNF-Ī±) is elevated in individuals with MPS I and II and associated with pain and physical dysfunction. Therefore, we evaluated the safety and effects of the TNF-Ī± inhibitor adalimumab in patients with MPS I and II in a 32-week, randomized, double blind, placebo-controlled, crossover study of adalimumab at a dose of 20 mg (weight 15-<30 kg) or 40 mg (weight ā„ 30 kg) administered subcutaneously every other week or saline placebo for 16 weeks. Participants were evaluated at baseline, week 16, and week 32 with the Children's Health Questionnaire - Parent Form 50 (CHQ-PF50), the Pediatric Pain Questionnaire (PPQ), range-of-motion (ROM) measurements, anthropometry, six-minute walk test (6MWT), hand dynamometer, and laboratory evaluations for safety. The primary outcome was safety and primary efficacy outcome was bodily pain (BP) measured by the CHQ-PF50. Two subjects, one with MPS I and one with MPS II, completed the study. Adalimumab was well tolerated and there were no serious adverse events. Standardized BP scores for age and gender were higher (i.e. less pain) at the end of the treatment versus placebo phase for both subjects. Subject #1 became unblinded during treatment due to skin erythema. Behavior measured by both CHQ-PF50 and parental report improved during treatment compared to placebo in both subjects. ROM improved by > 5Ā° in seven of eight joints in Subject #1 and five of eight joints in Subject #2 (range 7.0Ā° to 52.8Ā°). There was no change in the PPQ, 6MWT, or hand dynamometer. Data from this small pilot study suggest that treatment with adalimumab is safe, tolerable, and may improve ROM, physical function, and possibly pain, in children with MPS I or II. However, additional clinical trials are needed before this therapy should be recommended as part of clinical care
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Broad spectrum proteomics analysis of the inferior colliculus following acute hydrogen sulfide exposure.
Acute exposure to high concentrations of H2S causes severe brain injury and long-term neurological disorders, but the mechanisms involved are not known. To better understand the cellular and molecular mechanisms involved in acute H2S-induced neurodegeneration we used a broad-spectrum proteomic analysis approach to identify key molecules and molecular pathways involved in the pathogenesis of acute H2S-induced neurotoxicity and neurodegeneration. Mice were subjected to acute inhalation exposure of up to750 ppm of H2S. H2S induced behavioral deficits and severe lesions including hemorrhage in the inferior colliculus (IC). The IC was microdissected for proteomic analysis. Tandem mass tags (TMT) liquid chromatography mass spectrometry (LC-MS/MS)-based quantitative proteomics was applied for protein identification and quantitation. LC-MS/MS identified 598, 562, and 546 altered proteomic changes at 2āÆh, and on days 2 and 4 post-H2S exposure, respectively. Of these, 77 proteomic changes were statistically significant at any of the 3 time points. Mass spectrometry data were subjected to Perseus 1.5.5.3 statistical analysis, and gene ontology heat map clustering. Expressions of several key molecules were verified to confirm H2S-dependent proteomics changes. Webgestalt pathway overrepresentation enrichment analysis with Panther engine revealed H2S exposure disrupted several biological processes including metabotropic glutamate receptor group 1 and inflammation mediated by chemokine and cytokine signaling pathways among others. Further analysis showed that energy metabolism, integrity of blood-brain barrier, hypoxic, and oxidative stress signaling pathways were also implicated. Collectively, this broad-spectrum proteomics data has provided important clues to follow up in future studies to further elucidate mechanisms of H2S-induced neurotoxicity
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