1,589 research outputs found
Population of low-lying levels in the one-neutron halo nucleus 11Be via the neutron transfer reaction 10Be(d,p)
Historically, measurements of differential cross-sections for the neutron transfer reaction (d, p) on stable targets have been an important tool for extracting spectroscopic information. In particular, it is possible to make orbital angular momentum assignments and extract spectroscopic factors for ground states and excited states by comparing measurements to cross sections calculated for pure single-particle states. In recent years, the advent of rare isotope beams have made it possible to apply this method to increasingly exotic nuclei. As nucleon separation energies decrease along the path to the proton and neutron drip lines, many new reaction channels are opened. Out of the open channels arise complications for theoretical calculations that are not well understood. The archetypal one neutron halo nucleus 11Be has been an important test case for theoretical studies, being within the reach of ab initio theory and relatively near the valley of particle stability while possessing several exotic properties. Although its ground state properties have been studied thoroughly, spectroscopic factors for the first excited state are not well understood. Additionally, little is known about the low-lying resonances. The current study has been performed to provide an extensive data set for the reaction 10Be(d, p) in inverse kinematics, including elastic and inelastic scattering channels important for optical model parameterizations. Differential cross-sections have been measured at equivalent deuteron beam energies of 12, 15, 18, and 21.4 MeV. Results are compared to previous measurements in inverse kinematics at 12 and 25 MeV. The data are also used to evaluate the Distorted Wave Born Approximation and Adiabatic Distorted Wave Approximation methods for cross section calculations and spectroscopic factors are extracted in each case
The Atypical Stimulant and Nootropic Modafinil Interacts with the Dopamine Transporter in a Different Manner than Classical Cocaine-Like Inhibitors
Modafinil is a mild psychostimulant with pro-cognitive and antidepressant effects. Unlike many conventional stimulants, modafinil has little appreciable potential for abuse, making it a promising therapeutic agent for cocaine addiction. The chief molecular target of modafinil is the dopamine transporter (DAT); however, the mechanistic details underlying modafinil's unique effects remain unknown. Recent studies suggest that the conformational effects of a given DAT ligand influence the magnitude of the ligand's reinforcing properties. For example, the atypical DAT inhibitors benztropine and GBR12909 do not share cocaine's notorious addictive liability, despite having greater binding affinity. Here, we show that the binding mechanism of modafinil is different than cocaine and similar to other atypical inhibitors. We previously established two mutations (W84L and D313N) that increase the likelihood that the DAT will adopt an outward-facing conformational state—these mutations increase the affinity of cocaine-like inhibitors considerably, but have little or opposite effect on atypical inhibitor binding. Thus, a compound's WT/mutant affinity ratio can indicate whether the compound preferentially interacts with a more outward- or inward-facing conformational state. Modafinil displayed affinity ratios similar to those of benztropine, GBR12909 and bupropion (which lack cocaine-like effects in humans), but far different than those of cocaine, β-CFT or methylphenidate. Whereas treatment with zinc (known to stabilize an outward-facing transporter state) increased the affinity of cocaine and methylphenidate two-fold, it had little or no effect on the binding of modafinil, benztropine, bupropion or GBR12909. Additionally, computational modeling of inhibitor binding indicated that while β-CFT and methylphenidate stabilize an “open-to-out” conformation, binding of either modafinil or bupropion gives rise to a more closed conformation. Our findings highlight a mechanistic difference between modafinil and cocaine-like stimulants and further demonstrate that the conformational effects of a given DAT inhibitor influence its phenomenological effects
An inbred line of the diploid strawberry Fragaria vesca f. semperflorens for genomic and molecular genetic studies in the Rosaceae
<p>Abstract</p> <p>Background</p> <p>The diploid woodland strawberry (<it>Fragaria vesca</it>) is an attractive system for functional genomics studies. Its small stature, fast regeneration time, efficient transformability and small genome size, together with substantial EST and genomic sequence resources make it an ideal reference plant for <it>Fragaria </it>and other herbaceous perennials. Most importantly, this species shares gene sequence similarity and genomic microcolinearity with other members of the Rosaceae family, including large-statured tree crops (such as apple, peach and cherry), and brambles and roses as well as with the cultivated octoploid strawberry, <it>F</it>. ×<it>ananassa</it>. <it>F. vesca </it>may be used to quickly address questions of gene function relevant to these valuable crop species. Although some <it>F. vesca </it>lines have been shown to be substantially homozygous, in our hands plants in purportedly homozygous populations exhibited a range of morphological and physiological variation, confounding phenotypic analyses. We also found the genotype of a named variety, thought to be well-characterized and even sold commercially, to be in question. An easy to grow, standardized, inbred diploid <it>Fragaria </it>line with documented genotype that is available to all members of the research community will facilitate comparison of results among laboratories and provide the research community with a necessary tool for functionally testing the large amount of sequence data that will soon be available for peach, apple, and strawberry.</p> <p>Results</p> <p>A highly inbred line, YW5AF7, of a diploid strawberry <it>Fragaria vesca </it>f. <it>semperflorens </it>line called "Yellow Wonder" (Y2) was developed and examined. Botanical descriptors were assessed for morphological characterization of this genotype. The plant line was found to be rapidly transformable using established techniques and media formulations.</p> <p>Conclusion</p> <p>The development of the documented YW5AF7 line provides an important tool for Rosaceae functional genomic analyses. These day-neutral plants have a small genome, a seed to seed cycle of 3.0 - 3.5 months, and produce fruit in 7.5 cm pots in a growth chamber. YW5AF7 is runnerless and therefore easy to maintain in the greenhouse, forms abundant branch crowns for vegetative propagation, and produces highly aromatic yellow fruit throughout the year in the greenhouse. <it>F. vesca </it>can be transformed with <it>Agrobacterium tumefaciens</it>, making these plants suitable for insertional mutagenesis, RNAi and overexpression studies that can be compared against a stable baseline of phenotypic descriptors and can be readily genetically substantiated.</p
Bringing Family Voice to Determinants of Health
The Family Leadership Training Institute (FLTI) is a program that can respond to data documenting the health of the nation. Participants engage in individual civic projects that align with social determinants of health and seek to ameliorate health inequities. They also discover and/or increase their civic engagement skills to more effectively take part in policy and implementation discussions and decisions. With roots in Colorado, FLTI continues to expand into rural and urban communities throughout the state. The curriculum has been translated into Spanish, and a two-generation pilot implementation has indicated promise for including youths in a parallel program. Documentation regarding program effectiveness suggests that others in Extension may benefit interested communities by assisting them in replicating FLTI
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Common DNA sequence variation influences 3-dimensional conformation of the human genome.
BACKGROUND:The 3-dimensional (3D) conformation of chromatin inside the nucleus is integral to a variety of nuclear processes including transcriptional regulation, DNA replication, and DNA damage repair. Aberrations in 3D chromatin conformation have been implicated in developmental abnormalities and cancer. Despite the importance of 3D chromatin conformation to cellular function and human health, little is known about how 3D chromatin conformation varies in the human population, or whether DNA sequence variation between individuals influences 3D chromatin conformation. RESULTS:To address these questions, we perform Hi-C on lymphoblastoid cell lines from 20 individuals. We identify thousands of regions across the genome where 3D chromatin conformation varies between individuals and find that this variation is often accompanied by variation in gene expression, histone modifications, and transcription factor binding. Moreover, we find that DNA sequence variation influences several features of 3D chromatin conformation including loop strength, contact insulation, contact directionality, and density of local cis contacts. We map hundreds of quantitative trait loci associated with 3D chromatin features and find evidence that some of these same variants are associated at modest levels with other molecular phenotypes as well as complex disease risk. CONCLUSION:Our results demonstrate that common DNA sequence variants can influence 3D chromatin conformation, pointing to a more pervasive role for 3D chromatin conformation in human phenotypic variation than previously recognized
Proton radiation effects on carrier transport in diamond radiation detectors
Diamond, a highly radiation-resistant material, is considered a nearly ideal material for radiation detection, particularly in high-energy physics. In this study, radiation damage from high-energy proton beams was induced in diamond crystals to determine exposure lifetime in detectors made from this material; the effects were investigated using non-destructive x-ray techniques and through the FLUKA simulation package. Two diamond detectors were irradiated by an 800 MeV proton beam at different fluence rates, and the real-time current response was recorded to observe degradation in the signal over time. It was determined that the proton fluence rate had a significant effect on the device degradation. The detector performance from the irradiated detectors was characterized using x-ray beam-induced current measurements, and the mechanism of proton radiation damage to diamond sensors, especially the radiation effects on carrier transport, was studied. The vacancies generated from proton irradiation were considered the major source of detector degradation by trapping holes and inducing an internal electric field. Simulation results from the FLUKA package revealed an uneven distribution of the radiation-induced vacancies along the beam path, and the corresponding detector signals calculated from the simulation results displayed a good match to the experimental results
Kepler Eclipsing Binary Stars. VI. Identification of Eclipsing Binaries in the K2 Campaign 0 Data-set
The original {\it Kepler} mission observed and characterized over 2400
eclipsing binaries in addition to its prolific exoplanet detections. Despite
the mechanical malfunction and subsequent non-recovery of two reaction wheels
used to stabilize the instrument, the {\it Kepler} satellite continues
collecting data in its repurposed {\it K2} mission surveying a series of fields
along the ecliptic plane. Here we present an analysis of the first full
baseline {\it K2} data release: the Campaign 0 data-set. In the 7761 light
curves, we have identified a total of 207 eclipsing binaries. Of these, 97 are
new discoveries that were not previously identified. Our pixel-level analysis
of these objects has also resulted in identification of several false positives
(observed targets contaminated by neighboring eclipsing binaries), as well as
the serendipitous discovery of two short period exoplanet candidates. We
provide catalog cross-matched source identifications, orbital periods,
morphologies and ephemerides for these eclipsing systems. We also describe the
incorporation of the K2 sample into the Kepler Eclipsing Binary
Catalog\footnote{\url{keplerebs.villanova.edu/k2}}, present spectroscopic
follow-up observations for a limited selection of nine systems, and discuss
prospects for upcoming {\it K2} campaigns.Comment: Accepted for publication in MNRAS. 51 pages [20 figures, 8 tables].
Results available online in the Kepler Eclipsing Binary Star Catalog
http://keplerebs.villanova.edu/k
Monitoring results after 36 ktonnes of deep CO2 injection at the Aquistore CO2 storage site, Saskatchewan, Canada
The Aquistore CO2 Storage Site is located in southeastern Saskatchewan, Canada. CO2 is injected into a brine-filled sandstone formation at ∼3200 m depth immediately above the Precambrian basement. Sustained injection rates of 400-600 tonnes/day were achieved at the site starting in the fall of 2015 with
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