267 research outputs found
Dublin Core Metadata Harvested Through OAI-PMH
The introduction in 2001 of the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) increased interest in and awareness of metadata quality issues relevant to digital library interoperability and the use of harvested metadata to build "union catalogs" of digital information resources. Practitioners have offered wide-ranging advice to metadata authors and have suggested metrics useful for measuring the quality of shareable metadata. Is there evidence of changes in metadata practice in response to such advice and/or as a result of an increased awareness of the importance of metadata interoperability? This paper looks at metadata records created over a six-year period that have been harvested by the University of Illinois at Urbana Champaign, and reports on quantitative and qualitative analyses of changes observed over time in shareable metadata quality.IMLS National Leadership Grant LG-02-02-0281published or submitted for publicationis peer reviewe
Perspective From a Youth Environmental Activist: Why Adults Will Listen to Youth in Politics
This perspective article is divided between the account of an emerging youth political activist, Katelyn Higgins, and the subsequent collaborative research project she coordinated. After 10 years of experience in youth political action, Higgins worked with co-authors to develop a qualitative study to explore the processes underlying youth influence over local environmental policymaking. We present findings from that study to supplement her perspective. The study supported fourth and fifth grade teachers by offering a marine debris curriculum which encouraged students to share their knowledge with local community members through environmental activism events. At the first event, students aged 8–10 presented at a town hall meeting; we interviewed 16 adults in attendance. The second “event” was a series of video PSAs (Public Service Announcements) in which students from across the state of North Carolina, United States, explained the harms of marine debris. Those PSAs were emailed to local officials; we conducted follow-up interviews with two officials. Four themes emerged to characterize how adults responded to youth environmental activism: young people were inspiring; adults want to support young people; and adults view young people as able to provide leadership for local action and challenge the establishment. Youth leaders and those looking to support them should be encouraged by these results, as they suggest adults, including local public officials, consider youth voices valuable and uniquely situated to foster productive political processes for addressing marine debris. Future research should continue to explore the degree to which positive feelings expressed by adults translate to action
Imaging ultrafast excited state pathways in transition metal complexes by X-ray transient absorption and scattering using X-ray free electron laser source
This report will describe our recent studies of transition metal complex structural dynamics on the fs and ps time scales using an X-ray free electron laser source, Linac Coherent Light Source (LCLS). Ultrafast XANES spectra at the Ni K-edge of nickel(II) tetramesitylporphyrin (NiTMP) were successfully measured for optically excited state at a timescale from 100 fs to 50 ps, providing insight into its sub-ps electronic and structural relaxation processes. Importantly, a transient reduced state Ni(I) (π, 3d(x2−y2)) electronic state is captured through the interpretation of a short-lived excited state absorption on the low-energy shoulder of the edge, which is aided by the computation of X-ray transitions for postulated excited electronic states. The observed and computed inner shell to valence orbital transition energies demonstrate and quantify the influence of electronic configuration on specific metal orbital energies. A strong influence of the valence orbital occupation on the inner shell orbital energies indicates that one should not use the transition energy from 1s to other orbitals to draw conclusions about the d-orbital energies. For photocatalysis, a transient electronic configuration could influence d-orbital energies up to a few eV and any attempt to steer the reaction pathway should account for this to ensure that external energies can be used optimally in driving desirable processes. NiTMP structural evolution and the influence of the porphyrin macrocycle conformation on relaxation kinetics can be likewise inferred from this study
Association of Blood Biomarkers With Acute Sport-Related Concussion in Collegiate Athletes: Findings From the NCAA and Department of Defense CARE Consortium
Importance:
There is potential scientific and clinical value in validation of objective biomarkers for sport-related concussion (SRC).
Objective:
To investigate the association of acute-phase blood biomarker levels with SRC in collegiate athletes.
Design, Setting, and Participants:
This multicenter, prospective, case-control study was conducted by the National Collegiate Athletic Association (NCAA) and the US Department of Defense Concussion Assessment, Research, and Education (CARE) Consortium from February 20, 2015, to May 31, 2018, at 6 CARE Advanced Research Core sites. A total of 504 collegiate athletes with concussion, contact sport control athletes, and non-contact sport control athletes completed clinical testing and blood collection at preseason baseline, the acute postinjury period, 24 to 48 hours after injury, the point of reporting being asymptomatic, and 7 days after return to play. Data analysis was conducted from March 1 to November 30, 2019.
Main Outcomes and Measures:
Glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament light chain, and tau were quantified using the Quanterix Simoa multiplex assay. Clinical outcome measures included the Sport Concussion Assessment Tool-Third Edition (SCAT-3) symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, and Brief Symptom Inventory 18.
Results:
A total of 264 athletes with concussion (mean [SD] age, 19.08 [1.24] years; 211 [79.9%] male), 138 contact sport controls (mean [SD] age, 19.03 [1.27] years; 107 [77.5%] male), and 102 non-contact sport controls (mean [SD] age, 19.39 [1.25] years; 82 [80.4%] male) were included in the study. Athletes with concussion had significant elevation in GFAP (mean difference, 0.430 pg/mL; 95% CI, 0.339-0.521 pg/mL; P < .001), UCH-L1 (mean difference, 0.449 pg/mL; 95% CI, 0.167-0.732 pg/mL; P < .001), and tau levels (mean difference, 0.221 pg/mL; 95% CI, 0.046-0.396 pg/mL; P = .004) at the acute postinjury time point compared with preseason baseline. Longitudinally, a significant interaction (group × visit) was found for GFAP (F7,1507.36 = 16.18, P < .001), UCH-L1 (F7,1153.09 = 5.71, P < .001), and tau (F7,1480.55 = 6.81, P < .001); the interaction for neurofilament light chain was not significant (F7,1506.90 = 1.33, P = .23). The area under the curve for the combination of GFAP and UCH-L1 in differentiating athletes with concussion from contact sport controls at the acute postinjury period was 0.71 (95% CI, 0.64-0.78; P < .001); the acute postinjury area under the curve for all 4 biomarkers combined was 0.72 (95% CI, 0.65-0.79; P < .001). Beyond SCAT-3 symptom score, GFAP at the acute postinjury time point was associated with the classification of athletes with concussion from contact controls (β = 12.298; 95% CI, 2.776-54.481; P = .001) and non-contact sport controls (β = 5.438; 95% CI, 1.676-17.645; P = .005). Athletes with concussion with loss of consciousness or posttraumatic amnesia had significantly higher levels of GFAP than athletes with concussion with neither loss of consciousness nor posttraumatic amnesia at the acute postinjury time point (mean difference, 0.583 pg/mL; 95% CI, 0.369-0.797 pg/mL; P < .001).
Conclusions and Relevance:
The results suggest that blood biomarkers can be used as research tools to inform the underlying pathophysiological mechanism of concussion and provide additional support for future studies to optimize and validate biomarkers for potential clinical use in SRC
Ultrafast Excited State Relaxation of a Metalloporphyrin Revealed by Femtosecond X-ray Absorption Spectroscopy
Photoexcited Nickel(II) tetramesitylporphyrin
(NiTMP), like many
open-shell metalloporphyrins, relaxes rapidly through multiple electronic
states following an initial porphyrin-based excitation, some involving
metal centered electronic configuration changes that could be harnessed
catalytically before excited state relaxation. While a NiTMP excited
state present at 100 ps was previously identified by X-ray transient
absorption (XTA) spectroscopy at a synchrotron source as a relaxed
(d,d) state, the lowest energy excited state (<i>J. Am. Chem.
Soc.</i>, <b>2007</b>, <i>129</i>, 9616 and <i>Chem. Sci.</i>, <b>2010</b>, <i>1</i>, 642),
structural dynamics before thermalization were not resolved due to
the ∼100 ps duration of the available X-ray probe pulse. Using
the femtosecond (fs) X-ray pulses of the Linac Coherent Light Source
(LCLS), the Ni center electronic configuration from the initial excited
state to the relaxed (d,d) state has been obtained via ultrafast Ni
K-edge XANES (X-ray absorption near edge structure) on a time scale
from hundreds of femtoseconds to 100 ps. This enabled the identification
of a short-lived Ni(I) species aided by time-dependent density functional
theory (TDDFT) methods. Computed electronic and nuclear structure
for critical excited electronic states in the relaxation pathway characterize
the dependence of the complex’s geometry on the electron occupation
of the 3d orbitals. Calculated XANES transitions for these excited
states assign a short-lived transient signal to the spectroscopic
signature of the Ni(I) species, resulting from intramolecular charge
transfer on a time scale that has eluded previous synchrotron studies.
These combined results enable us to examine the excited state structural
dynamics of NiTMP prior to thermal relaxation and to capture intermediates
of potential photocatalytic significance
Myocardial dysfunction in the periinfarct and remote regions following anterior infarction in rats quantified by 2D radial strain echocardiography: An observational cohort study
<p>Abstract</p> <p>Background</p> <p>Heart failure from adverse ventricular remodeling follows myocardial infarction, but the contribution of periinfarct and remote myocardium to the development of cardiomyopathy remains poorly defined. 2D strain echocardiography (2DSE) is a novel and sensitive tool to measure regional myocardial mechanics. The aim is to quantify radial strain in infarcted (I), periinfarct (PI) and remote (R) myocardial regions acutely and chronically following anterior infarction in rats.</p> <p>Methods</p> <p>The left anterior coronary artery of male Sprague-Dawley rats (270–370 g) were occluded for 20–30 minutes and 2DSE was performed in the acute setting (n = 10; baseline and 60 minutes post-reperfusion) and in the chronic setting (n = 14; baseline, 1, 3 and 6 weeks). Using software, radial strain was measured in the mid-ventricle in short axis view. The ventricle was divided into 3 regions: I (anteroseptum, anterior and anterolateral), PI – (inferoseptum and inferolateral) and R – (inferior). Infarct size was measured using triphenyl tetrazolium chloride in the acute group.</p> <p>Results</p> <p>Following infarct, adverse remodeling occurred with progressive increase in left ventricular size, mass and reduced fractional shortening within 6 weeks. Radial strain decreased not only in the infarct but also in the periinfarct and remote regions acutely and chronically (I, PI, R, change vs. baseline, 60 minutes -32.7 ± 8.7, -17.4 ± 9.4, -13.5 ± 11.6%; 6 weeks -24.4 ± 8.2, -17.7 ± 8.3, -15.2 ± 8.4% respectively, all p < 0.05). Reduced radial strain in periinfarct and remote regions occurred despite minimal or absent necrosis (area of necrosis I, PI, R: 48.8 ± 23, 5.1 ± 6.6, 0 ± 0%, p < 0.001 vs. I).</p> <p>Conclusion</p> <p>Following left anterior coronary occlusion, radial strain decreased at 60 minutes and up to 6 weeks in the periinfarct and remote regions, similar to the reduction in the infarct region. This demonstrates early and chronic myopathic process in periinfarct and remote regions following myocardial infarction that may be an under recognized but important contributor to adverse left ventricular remodeling and progression to ischemic cardiomyopathy.</p
STAT3 gain-of-function mutations connect leukemia with autoimmune disease by pathological NKG2Dhi CD8+T cell dysregulation and accumulation
The association between cancer and autoimmune disease is unexplained, exemplified by T cell large granular lymphocytic leukemia (T-LGL) where gain-of-function (GOF) somatic STAT3 mutations correlate with co -exist-ing autoimmunity. To investigate whether these mutations are the cause or consequence of CD8+ T cell clonal expansions and autoimmunity, we analyzed patients and mice with germline STAT3 GOF mutations. STAT3 GOF mutations drove the accumulation of effector CD8+ T cell clones highly expressing NKG2D, the receptor for stress-induced MHC-class-I-related molecules. This subset also expressed genes for granzymes, perforin, interferon-y, and Ccl5/Rantes and required NKG2D and the IL-15/IL-2 receptor IL2RB for maximal accumula-tion. Leukocyte-restricted STAT3 GOF was sufficient and CD8+ T cells were essential for lethal pathology in mice. These results demonstrate that STAT3 GOF mutations cause effector CD8+ T cell oligoclonal accumu-lation and that these rogue cells contribute to autoimmune pathology, supporting the hypothesis that somatic mutations in leukemia/lymphoma driver genes contribute to autoimmune disease.Peer reviewe
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