1,332 research outputs found

    Dipole-Coupled Neutrissimo Explanations of the MiniBooNE Excess Including Constraints from MINERvA Data

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    We revisit models of heavy neutral leptons (neutrissimos) with transition magnetic moments as explanations of the 4.8σ4.8\sigma excess of electron-like events at MiniBooNE. We perform a detailed Monte Carlo-based analysis to re-examine the preferred regions in the model parameter space to explain MiniBooNE, considering also potential contributions from oscillations due to an eV-scale sterile neutrino. We then derive robust constraints on the model using neutrino-electron elastic scattering data from MINERvA. We find that MINERvA rules out a large region of parameter space, but allowed solutions exist at the 2σ2\sigma confidence level. A dedicated MINERvA analysis would likely be able to probe the entire region of preference of MiniBooNE in this model.Comment: 14 page

    Structural basis of differential neutralization of DENV-1 genotypes by an antibody that recognizes a cryptic epitope

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    We previously developed a panel of neutralizing monoclonal antibodies against Dengue virus (DENV)-1, of which few exhibited inhibitory activity against all DENV-1 genotypes. This finding is consistent with reports observing variable neutralization of different DENV strains and genotypes using serum from individuals that experienced natural infection or immunization. Herein, we describe the crystal structures of DENV1-E111 bound to a novel CC' loop epitope on domain III (DIII) of the E protein from two different DENV-1 genotypes. Docking of our structure onto the available cryo-electron microscopy models of DENV virions revealed that the DENV1-E111 epitope was inaccessible, suggesting that this antibody recognizes an uncharacterized virus conformation. While the affinity of binding between DENV1-E111 and DIII varied by genotype, we observed limited correlation with inhibitory activity. Instead, our results support the conclusion that potent neutralization depends on genotype-dependent exposure of the CC' loop epitope. These findings establish new structural complexity of the DENV virion, which may be relevant for the choice of DENV strain for induction or analysis of neutralizing antibodies in the context of vaccine development

    The Fc region of an antibody impacts the neutralization of West Nile viruses in different maturation states

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    Flavivirus-infected cells secrete a structurally heterogeneous population of viruses because of an inefficient virion maturation process. Flaviviruses assemble as noninfectious, immature virions composed of trimers of envelope (E) and precursor membrane (prM) protein heterodimers. Cleavage of prM is a required process during virion maturation, although this often remains incomplete for infectious virus particles. Previous work demonstrated that the efficiency of virion maturation could impact antibody neutralization through changes in the accessibility of otherwise cryptic epitopes on the virion. In this study, we show that the neutralization potency of monoclonal antibody (MAb) E33 is sensitive to the maturation state of West Nile virus (WNV), despite its recognition of an accessible epitope, the domain III lateral ridge (DIII-LR). Comprehensive epitope mapping studies with 166 E protein DIII-LR variants revealed that the functional footprint of MAb E33 on the E protein differs subtly from that of the well-characterized DIII-LR MAb E16. Remarkably, aromatic substitutions at E protein residue 306 ablated the maturation state sensitivity of E33 IgG, and the neutralization efficacy of E33 Fab fragments was not affected by changes in the virion maturation state. We propose that E33 IgG binding on mature virions orients the Fc region in a manner that impacts subsequent antibody binding to nearby sites. This Fc-mediated steric constraint is a novel mechanism by which the maturation state of a virion modulates the efficacy of the humoral immune response to flavivirus infection

    Historical Analysis of Bibliometric Trends in the Journal of Pediatric Orthopaedics With a Particular Focus on Sex

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    Background: Orthopaedics is the clinical discipline with the lowest percentage of female residents and faculty. Pediatric orthopaedics has a higher percentage of women than other orthopaedic subspecialties. It was the purpose of this study to examine bibliometric trends in the Journal of Pediatric Orthopaedics (JPO) with a specific focus on sex. Methods: A bibliometeric analysis for the years 2015, 2005, 1995, 1985, 1981 was performed. The names of first and corresponding authors; corresponding author position; country of origin; number of institutions, countries, authors, printed pages, and references was tabulated. Author sex was identified for the first and corresponding authors using the “Baby Name Guesser” (www.gpeters.com/names/baby-names.php). A P<0.05 was considered significant. Results: There were 746 publications; 68.7% were from North America. The average number of authors, corresponding author position, collaborating institutions, countries, and number of references increased, whereas the number of printed pages decreased. Asia had the greatest number of authors (4.4), with Australia/New Zealand the fewest (3.4). Sex was determined for 98.3% of the first authors and 98.5% of the corresponding authors. There was a significant increase in the number of female first authors over time (5.9% to 25.6%, P<10−6), especially in Europe and North America. There were significant increase in the number of female corresponding authors over time (5.8% to 17.6%, P=0.000009). There was a significant trend to have a greater percentage of both female first and corresponding authors over time (P=0.0005) with a reverse trend for both male first and corresponding authors (P<10−6). Conclusions: In this study, we noted that the number of female first and corresponding authors in Journal of Pediatric Orthopaedics has been steadily increasing. This should result in more female pediatric orthopaedic surgeons in academic faculty positions

    Potent Dengue virus neutralization by a therapeutic antibody with low monovalent affinity requires bivalent engagement

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    We recently described our most potently neutralizing monoclonal antibody, E106, which protected against lethal Dengue virus type 1 (DENV-1) infection in mice. To further understand its functional properties, we determined the crystal structure of E106 Fab in complex with domain III (DIII) of DENV-1 envelope (E) protein to 2.45 Å resolution. Analysis of the complex revealed a small antibody-antigen interface with the epitope on DIII composed of nine residues along the lateral ridge and A-strand regions. Despite strong virus neutralizing activity of E106 IgG at picomolar concentrations, E106 Fab exhibited a ∼20,000-fold decrease in virus neutralization and bound isolated DIII, E, or viral particles with only a micromolar monovalent affinity. In comparison, E106 IgG bound DENV-1 virions with nanomolar avidity. The E106 epitope appears readily accessible on virions, as neutralization was largely temperature-independent. Collectively, our data suggest that E106 neutralizes DENV-1 infection through bivalent engagement of adjacent DIII subunits on a single virion. The isolation of anti-flavivirus antibodies that require bivalent binding to inhibit infection efficiently may be a rare event due to the unique icosahedral arrangement of envelope proteins on the virion surface

    Bibliometric Analysis of Female Authorship Trends and Collaboration Dynamics Over JBMR's 30-Year History

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    In academia, authorship is considered a currency and is important for career advancement. As the Journal of Bone and Mineral Research (JBMR) is the highest-ranked journal in the field of bone, muscle, and mineral metabolism and is the official publication of the American Society for Bone and Mineral Research, we sought to examine authorship changes over JBMR's 30-year history. Two bibliometric methods were used to collect the data. The “decade method” included all published manuscripts throughout 1 year in each decade over the past 30 years starting with the inaugural year, yielding 746 manuscripts for analysis. The “random method” examined 10% of published manuscripts from each of the 30 years, yielding 652 manuscripts for analysis. Using both methods, the average number of authors per manuscript, numerical location of the corresponding author, number of collaborating institutions, number of collaborating countries, number of printed manuscript pages, and the number of times each manuscript was cited all significantly increased between 1986 and 2015 (p < 10−4). Using the decade method, there was a significant increase in the percentage of female first authors over time from 35.8% in 1986 to 47.7% in 2015 (p = 0.02), and this trend was confirmed using the random method. The highest percentage of female first authors in 2015 was in Europe (60.0%), and Europe also had the most dramatic increase in female first authors over time (more than double in 2015 compared with 1986). Likewise, the overall number of female corresponding authors significantly increased during the past 30 years. With the increasing demands of publishing in academic medicine, understanding changes in publishing characteristics over time and by geographical region is important. These findings highlight JBMR's authorship trends over the past 30 years and demonstrate those countries having the most changes and where challenges still exist

    Bi-cultural dynamics for risk and protective factors for cardiometabolic health in an Alaska Native (Yup\u27ik) population

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    Alaska Native people experience disparities in mortality from heart disease and stroke. This work attempts to better understand the relationships between socioeconomic, behavioral, and cardiometabolic risk factors among Yup\u27ik people of southwestern Alaska, with a focus on the role of the socioeconomic, and cultural components. Using a cross-sectional sample of 486 Yup\u27ik adults, we fitted a Partial Least Squares Path Model (PLS-PM) to assess the associations between components, including demographic factors [age and gender], socioeconomic factors [education, economic status, Yup\u27ik culture, and Western culture], behavioral factors [diet, cigarette smoking and smokeless tobacco use, and physical activity], and cardiometabolic risk factors [adiposity, triglyceride-HDL and LDL lipids, glycemia, and blood pressure]. We found relatively mild associations of education and economic status with cardiometabolic risk factors, in contrast with studies in other populations. The socioeconomic factor and participation in Yup\u27ik culture had potentially protective associations with adiposity, triglyceride-HDL lipids, and blood pressure, whereas participation in Western culture had a protective association with blood pressure. We also found a moderating effect of participation in Western culture on the relationships between Yup\u27ik culture participation and both blood pressure and LDL lipids, indicating a potentially beneficial additional effect of biculturalism. Our results suggest that reinforcing protective effects of both Yup\u27ik and Western cultures could be useful for interventions aimed at reducing cardiometabolic health disparities

    Bibliometric analysis of authorship trends and collaboration dynamics over the past three decades of BONE's publication history

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    The existence of a gender gap in academia has been a hotly debated topic over the past several decades. It has been argued that due to the gender gap, it is more difficult for women to obtain higher positions. Manuscripts serve as an important measurement of one's accomplishments within a particular field of academia. Here, we analyzed, over the past 3 decades, authorship and other trends in manuscripts published in BONE, one of the premier journals in the field of bone and mineral metabolism. For this study, one complete year of manuscripts was evaluated (e.g. 1985, 1995, 2005, 2015) for each decade. A bibliometric analysis was then performed of authorship trends for those manuscripts. Analyzed fields included: average number of authors per manuscript, numerical position of the corresponding author, number of institutions collaborating on each manuscript, number of countries involved with each manuscript, number of references, and number of citations per manuscript. Each of these fields increased significantly over the 30-year time frame (p < 10− 6). The gender of both the first and corresponding authors was identified and analyzed over time and by region. There was a significant increase in the percentage of female first authors from 23.4% in 1985 to 47.8% in 2015 (p = 0.001). The percentage of female corresponding authors also increased from 21.2% in 1985 to 35.4% in 2015 although it was not significant (p = 0.07). With such a substantial emphasis being placed on publishing in academic medicine, it is crucial to comprehend the changes in publishing characteristics over time and geographical region. These findings highlight authorship trends in BONE over time as well as by region. Importantly, these findings also highlight where challenges still exist

    Population Pharmacokinetic Modeling of Total and Free Ceftriaxone in Critically Ill Children and Young Adults and Monte Carlo Simulations Support Twice Daily Dosing for Target Attainment

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    Critical illness, including sepsis, causes significant pathophysiologic changes that alter the pharmacokinetics (PK) of antibiotics. Ceftriaxone is one of the most prescribed antibiotics in patients admitted to the pediatric intensive care unit (PICU). We sought to develop population PK models of both total ceftriaxone and free ceftriaxone in children admitted to a single-center PICU using a scavenged opportunistic sampling approach. We tested if the presence of sepsis and phase of illness (before or after 48 h of antibiotic treatment) altered ceftriaxone PK parameters. We performed Monte Carlo simulations to evaluate whether dosing regimens commonly used in PICUs in the United States (50 mg/kg of body weight every 12 h versus 24 h) resulted in adequate antimicrobial coverage. We found that a two-compartment model best described both total and free ceftriaxone concentrations. For free concentrations, the population clearance value is 6.54 L/h/70 kg, central volume is 25.4 L/70 kg, and peripheral volume is 19.6 L/70 kg. For both models, we found that allometric weight scaling, postmenstrual age, creatinine clearance, and daily highest temperature had significant effects on clearance. The presence of sepsis or phase of illness did not have a significant effect on clearance or volume of distribution. Monte Carlo simulations demonstrated that to achieve free concentrations above 1 mu g/ml for 100% of the dosing intervals, a dosing regimen of 50 mg/kg every 12 h is recommended for most patients. A continuous infusion could be considered if the target is to maintain free concentrations four times above the MICs (4 mu g/ml)
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