1,567 research outputs found
Neutron spectroscopic factors of Ni isotopes from transfer reactions
177 neutron spectroscopic factors for nickel isotopes have been extracted by
performing a systematic analysis of the angular distributions measured from
(d,p) transfer reactions. A subset of the extracted spectroscopic factors are
compared to predictions of large-basis shell models in the full pf model space
using the GXPF1A effective interaction, and the (f5/2, p3/2, p1/2, g9/2) model
space using the JJ4PNA interaction. For ground states, the predicted
spectroscopic factors using the GXPF1A effective interaction in the full pf
model space agree very well with the experimental values, while predictions
based on several other effective interactions and model spaces are about 30%
higher than the experimental values. For low-energy excited states (<3.5 MeV),
the agreement between the extracted spectroscopic factors and shell model
calculations is not better than a factor of two.Comment: 18 pages, 4 figures, 2 tables. accepted for publication in PR
Causal exposure-response curve estimation with surrogate confounders: a study of air pollution and children's health in Medicaid claims data
In this paper, we undertake a case study in which interest lies in estimating
a causal exposure-response function (ERF) for long-term exposure to fine
particulate matter (PM) and respiratory hospitalizations in
socioeconomically disadvantaged children using nationwide Medicaid claims data.
New methods are needed to address the specific challenges the Medicaid data
present. First, Medicaid eligibility criteria, which are largely based on
family income for children, differ by state, creating socioeconomically
distinct populations and leading to clustered data, where zip codes (our units
of analysis) are nested within states. Second, Medicaid enrollees'
individual-level socioeconomic status, which is known to be a confounder and an
effect modifier of the exposure-response relationships under study, is not
available. However, two useful surrogates are available: median household
income of each enrollee's zip code of residence and state-level Medicaid family
income eligibility thresholds for children. In this paper, we introduce a
customized approach, called \textit{MedMatch}, that builds on generalized
propensity score matching methods for estimating causal ERFs, adapting these
approaches to leverage our two surrogate variables to account for potential
confounding and/or effect modification by socioeconomic status. We conduct
extensive simulation studies, consistently demonstrating the strong performance
of \textit{MedMatch} relative to conventional approaches to handling the
surrogate variables. We apply \textit{MedMatch} to estimate the causal ERF
between long-term PM exposure and first respiratory hospitalization
among children in Medicaid from 2000 to 2012. We find a positive association,
with a steeper curve at PM g/m that levels off at higher
concentrations.Comment: 38 pages,5 figure
Applying Anti Oppressive, Empowerment, and Strengths Based Approaches to Social Work Practice with Hmong Clients
This conceptual article discusses social work practice with Hmong Americans using a framework that embraces anti-oppressive practice, empowerment and strengths-based approaches. Specifically, the Hmong kinship social construct of kwv tij neej tsa (pronounced: ku tee ning ja) is used to elaborate on the importance of upholding family relationships that transcends the worker-client relationship. Social workers are encouraged to empower Hmong to seek and ask for resources that support their collective value of connection to family and group identity, which is a strength that contributes to resilience and buffers against historically oppressive practices and systems
On Determining Dead Layer and Detector Thicknesses for a Position-Sensitive Silicon Detector
In this work, two particular properties of the position-sensitive, thick
silicon detectors (known as the "E" detectors) in the High Resolution Array
(HiRA) are investigated: the thickness of the dead layer on the front of the
detector, and the overall thickness of the detector itself. The dead layer
thickness for each E detector in HiRA is extracted using a measurement of alpha
particles emitted from a Pb pin source placed close to the detector
surface. This procedure also allows for energy calibrations of the E detectors,
which are otherwise inaccessible for alpha source calibration as each one is
sandwiched between two other detectors. The E detector thickness is obtained
from a combination of elastically scattered protons and an energy-loss
calculation method. Results from these analyses agree with values provided by
the manufacturer.Comment: Accepted for publication in Nuclear Instruments and Methods in
Physics Researc
Loss of MECP2 Leads to Activation of P53 and Neuronal Senescence.
To determine the role for mutations of MECP2 in Rett syndrome, we generated isogenic lines of human induced pluripotent stem cells, neural progenitor cells, and neurons from patient fibroblasts with and without MECP2 expression in an attempt to recapitulate disease phenotypes in vitro. Molecular profiling uncovered neuronal-specific gene expression changes, including induction of a senescence-associated secretory phenotype (SASP) program. Patient-derived neurons made without MECP2 showed signs of stress, including induction of P53, and senescence. The induction of P53 appeared to affect dendritic branching in Rett neurons, as P53 inhibition restored dendritic complexity. The induction of P53 targets was also detectable in analyses of human Rett patient brain, suggesting that this disease-in-a-dish model can provide relevant insights into the human disorder
Ultraparamagnetic cells formed through intracellular oxidation and chelation of paramagnetic iron
Making cells magnetic is a long‐standing goal of chemical biology, aiming to enable the separation of cells from complex biological samples and their visualization in vivo using magnetic resonance imaging (MRI). Previous efforts towards this goal, focused on engineering cells to biomineralize superparamagnetic or ferromagnetic iron oxides, have been largely unsuccessful due to the stringent required chemical conditions. Here, we introduce an alternative approach to making cells magnetic, focused on biochemically maximizing cellular paramagnetism. We show that a novel genetic construct combining the functions of ferroxidation and iron chelation enables engineered bacterial cells to accumulate iron in “ultraparamagnetic” macromolecular complexes, allowing these cells to be trapped with magnetic fields and imaged with MRI in vitro and in vivo. We characterize the properties of these cells and complexes using magnetometry, nuclear magnetic resonance, biochemical assays, and computational modeling to elucidate the unique mechanisms and capabilities of this paramagnetic concept
Investigations of three, four, and five-particle exit channels of levels in light nuclei created using a 9C beam
The interactions of a E/A=70-MeV 9C beam with a Be target was used to
populate levels in Be, B, and C isotopes which undergo decay into many-particle
exit channels. The decay products were detected in the HiRA array and the level
energies were identified from their invariant mass. Correlations between the
decay products were examined to deduce the nature of the decays, specifically
to what extent all the fragments were created in one prompt step or whether the
disintegration proceeded in a sequential fashion through long-lived
intermediate states. In the latter case, information on the spin of the level
was also obtained. Of particular interest is the 5-body decay of the 8C ground
state which was found to disintegrate in two steps of two-proton decay passing
through the 6Beg.s. intermediate state. The isobaric analog of 8Cg.s. in 8B was
also found to undergo two-proton decay to the isobaric analog of 6Beg.s. in
6Li. A 9.69-MeV state in 10C was found to undergo prompt 4-body decay to the
2p+2alpha exit channel. The two protons were found to have a strong
enhancementin the diproton region and the relative energies of all four p-alpha
pairs were consistent with the 5Lig.s. resonance
Permissive Transcriptional Activity at the Centromere through Pockets of DNA Hypomethylation
DNA methylation is a hallmark of transcriptional silencing, yet transcription has been reported at the centromere. To address this apparent paradox, we employed a fully sequence-defined ectopic human centromere (or neocentromere) to investigate the relationship between DNA methylation and transcription. We used sodium bisulfite PCR and sequencing to determine the methylation status of 2,041 CpG dinucleotides distributed across a 6.76-Mbp chromosomal region containing a neocentromere. These CpG dinucleotides were associated with conventional and nonconventional CpG islands. We found an overall hypermethylation of the neocentric DNA at nonconventional CpG islands that we designated as CpG islets and CpG orphans. The observed hypermethylation was consistent with the presence of a presumed transcriptionally silent chromatin state at the neocentromere. Within this neocentric chromatin, specific sites of active transcription and the centromeric chromatin boundary are defined by DNA hypomethylation. Our data demonstrate, for the first time to our knowledge, a correlation between DNA methylation and centromere formation in mammals, and that transcription and “chromatin-boundary activity” are permissible at the centromere through the selective hypomethylation of pockets of sequences without compromising the overall silent chromatin state and function of the centromere
The relationship of self-efficacy to catastrophizing and depressive symptoms in community-dwelling older adults with chronic pain: A moderated mediation model
Self-efficacy has been consistently found to be a protective factor against psychological distress and disorders in the literature. However, little research is done on the moderating effect of self-efficacy on depressive symptoms in the context of chronic pain. This cross-sectional study aimed to examine if pain self-efficacy attenuated the direct relationship between pain intensity and depressive symptoms, as well as their indirect relationship through reducing the extent of catastrophizing when feeling pain (moderated mediation). 664 community-dwelling Chinese older adults aged 60–95 years who reported chronic pain for at least three months were recruited from social centers. They completed a battery of questionnaires on chronic pain, pain self-efficacy, catastrophizing, and depressive symptoms in individual face-to-face interviews. Controlling for age, gender, education, self-rated health, number of chronic diseases, pain disability, and pain self-efficacy, pain catastrophizing was found to partially mediate the connection between pain intensity and depressive symptoms. Furthermore, the relationship between pain intensity and depressive symptoms was moderated by pain self-efficacy. Self-efficacy was also found to moderate the relationship between pain intensity and catastrophizing and the moderated mediation effect was confirmed using bootstrap analysis. The results suggested that with increasing levels of self-efficacy, pain intensity’s direct effect on depressive symptoms and its indirect effect on depressive symptoms via catastrophizing were both reduced in a dose-dependent manner. Our findings suggest that pain self-efficacy is a significant protective factor that contributes to psychological resilience in chronic pain patients by attenuating the relationship of pain intensity to both catastrophizing and depressive symptoms
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