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High-Resolution, Adaptive Optics Imaging of the Human Trabecular Meshwork In Vivo
No full textPurpose: To image the human trabecular meshwork (TM) in vivo using adaptive optics gonioscopy (AOG) with approximately 2-μm lateral resolution. Methods: An existing Indiana University adaptive optics scanning laser ophthalmoscope was altered by adding a 12-mm button lens to a clinical gonioscopic lens allowing high-resolution imaging of the human iridocorneal angle. First an anatomic model eye was used to refine the imaging technique and then nine participants (7 controls and 2 participants with pigment dispersion syndrome) were imaged. Results: All nine participants were successfully imaged without adverse events. High-resolution imaging of the human TM was achieved allowing for visualization of the TM beams, and presumed endothelial cells. Uveal meshwork beams in controls averaged 25.5 μm (range, 15.2–44.7) in diameter with pores averaging 42.6 μm (range, 22.3–51.4) while the corneoscleral meshwork pores averaged 8.9 μm (range, 7.7–12.1). Differences in appearance of the uveal and corneoscleral meshwork were noted between the two participants with pigment dispersion syndrome and the controls. These included nearly absent spacing between the beams and enlarged endothelial cells with hyperreflective areas. Conclusions: AOG allows for near cellular level resolution of the human TM in vivo. This may allow for further understanding of age-related changes that occur as well as provide a deeper understanding of medical and surgical alterations for the treatment of glaucoma. Translational Relevance: Further development of this approach may allow for direct measurements at a micometer level in vivo of changes that occur in the human trabecular meshwork with glaucoma and therapeutic interventions
Are all electrons the same? Evaluating support for local transmission lines through an experiment
No full textA crucial factor in U.S. energy infrastructure development is the degree to which citizens that reside near a development support or oppose the project. While the literature offers several explanations about what shapes individuals’ perceptions of energy projects, few have considered the importance of cognitive heuristics and the law of contagion. Here, we employ a survey experiment on a nationally-representative sample of 2,000 respondents to test whether knowing which energy resources connect to a high-voltage transmission line dictate support for the line. Results reveal that information about the source of electricity is fundamentally important. If a transmission line is said to carry electricity from a solar and wind development, a respondent is significantly more likely to support development of the line. If the line instead is said to carry electricity from a natural gas or coal plant, respectively, respondents are significantly less likely to support it. This study has implications for energy infrastructure development, messaging, and public acceptance of energy projects
Clinicopathological risk factors for gastric cancer: a retrospective cohort study in China
No full textObjective: To examine the potential clinicopathological factors affecting the prognosis of patients with gastric cancer after surgical treatment in China. Methods: Between 1 January 2001 and 31 December 2012, a total of 716 patients aged 22–84 years with gastric cancer were enrolled in the study. Survival analysis techniques including log rank test and Cox proportional hazard regression model were applied to evaluate the prognostic significance of clinicopathological characteristics in terms of survival time. Results: Of the 24 demographic and pathological variables collected in the data, 16 prognostic factors of gastric cancer were found to have statistically significant influences on survival time from the unadjusted analyses. The adjusted analysis furtherly revealed that age, age square, lymph node metastasis rate group, tumour size group, surgical type II, number of cancer nodules, invasion depth group and the interaction between surgical type II and tumour size group were important prognosis and clinicopathological factors for gastric cancer in Chinese. Conclusion: Our study with relatively large sample size and many potential risk factors enable us to identify independent risk factors associated with the prognosis of gastric cancer. Findings from the current study can be used to assist clinical decision-making, and serve as a benchmark for the planning of future prognosis and therapy for patients with gastric carcinoma
Hyperfield Grassmannians
No full textIn a recent paper Baker and Bowler introduced matroids over hyperfields, offering a common generalization of matroids, oriented matroids, and linear subspaces of based vector spaces. This paper introduces the notion of a topological hyperfield and explores the generalization of Grassmannians and realization spaces to this context, particularly in relating the (hyper)fields R and C to hyperfields arising in matroid theory and in tropical geometry
HIV Risk and Prevention Outcomes in a Probability-Based Sample of Gay and Bisexual Men in the United States
No full textBackground: Although gay and bisexual men (GBM) represent the largest group of HIV-infected individuals in the United States, nearly all evidence on their HIV risk and prevention outcomes derive from nonprobability samples. Setting: A probability-based cohort of GBM (N = 502) from 45 states and Washington, DC. Methods: Cross-sectional survey. Results: Among HIV-negative/unknown/untested GBM, only 6.7% reported using pre-exposure prophylaxis (PrEP) in the past 6 months. Two-thirds (63.3%) of PrEP users reported daily adherence in the past week. Over half (54.2%) of GBM reported not using a condom during anal sex with their most recent male partner; of these men, 93.8% were not on PrEP. Most GBM had been tested for HIV (80.7%) and other sexually transmitted infections (67.1%) in their lifetime, with 45.2% having tested for HIV during the past year. Among those ever tested, 14.1% reported being HIV infected, whereas an additional 8.9% reported testing positive for at least one other sexually transmitted infection after their most recent test. All HIV-positive GBM reported being currently on antiretroviral treatment, and 94.7% reported an undetectable viral load, but nearly one-third (30.4%) reported not taking their medication every day during the past month. A majority of HIV-negative/unknown/untested GBM (64.3%) reported that they had never discussed HIV prevention with their primary health care provider. Conclusions: Our findings present a decidedly mixed picture regarding the success of the US National HIV/AIDS Strategy in meeting its stated goals of addressing HIV risk among the general population of GBM
Radiation Brightening from Virus-like Particles
No full textConcentration quenching is a well-known challenge in many fluorescence imaging applications. Here we show that the optical emission from hundreds of chromophores confined onto the surface of a virus particle 28 nm diameter can be recovered under pulsed irradiation. We have found that, as one increases the number of chromophores tightly-bound to the virus surface, fluorescence quenching ensues at first, but when the number of chromophores per particle is nearing the maximum number of surface sites allowable, a sudden brightening of the emitted light and a shortening of the ex- cited state lifetime are observed. This radiation brightening occurs only under short pulse excitation; steady-state excitation is characterized by conventional concentration quenching for any number of chromophores per particle. The observed suppression of fluorescence quenching is consistent with efficient, collective radiation at room temper- ature. Interestingly, radiation brightening disappears when the emitters spatial and/or dynamic heterogeneity is increased, suggesting that the template structural properties may play a role and opening a way towards novel, virus-enabled imaging vectors that have qualitatively different optical properties than state-of-the-art biophotonic agents
Association of Increased Serum S100B Levels With High School Football Subconcussive Head Impacts
No full textAstrocyte-enriched marker, S100B, shows promise for gauging the severity of acute brain trauma, and understanding subconcussive effects will advance its utility in tracking real-time acute brain damage. The aim of the study was to investigate whether serum S100B elevations were associated with frequency and magnitude of subconcussive head impacts in adolescents. This prospective cohort study of 17 high-school football players consisted of the following 12 time points: pre-season baseline, 5 in-season pre-post games, and post-season. A sensor-installed mouthguard recorded the number of head impacts, peak linear (PLA) and peak rotational (PRA) head accelerations from every practice and game. During the 5 games, players wore chest-strap heart-rate monitors to estimate players' excess post-exercise oxygen consumption (EPOC), accounting for physical exertion effects. At each time point, blood samples were obtained and assessed for S100B and creatine kinase levels to account for astrocyte damage/activation and muscle damage, respectively. Using k-means clustering on the impact data, players were categorized into high- or low-impact group. Two players withdrew during the first month of the study. A total of 156 blood samples from 15 players were assessed for S100B and creatine kinase levels and included in the analysis. A median value of 596 head impacts from 15 players were recorded during all practices and games in a season. S100B levels were significantly elevated in all post-game measures compared with the respective pre-game values (median-increase, 0.022 μg/L; interquartile-range, 0.011–0.043 μg/L, p < 0.05 for all games). Greater acute S100B increases were significantly associated with greater impact frequency, sum of PLA and PRA, with negligible contributions from physical exertion and muscle damage effects. The high-impact group exhibited greater increases in serum S100B levels at post-games than the low-impact group (high vs. low, 0.043 ± 0.035 μg/L vs. 0.019 ± 0.017 μg/L, p = 0.002). The degree of acute S100B increases was correlated with subconcussive head impact exposure, suggesting that acute astrocyte damage may be induced in an impact-dependent manner. Acute changes in serum S100B levels may become a useful tool in monitoring real-time brain damage in sports
Gene set enrichment analysis to create polygenic scores: a developmental examination of aggression
No full textPrevious approaches for creating polygenic risk scores (PRSs) do not explicitly consider the biological or developmental relevance of the genetic variants selected for inclusion. We applied gene set enrichment analysis to meta-GWAS data to create developmentally targeted, functionally informed PRSs. Using two developmentally matched meta-GWAS discovery samples, separate PRSs were formed, then examined in time-varying effect models of aggression in a second, longitudinal sample of children (n = 515, 49% female) in early childhood (2–5 years old), and middle childhood (7.5–10.5 years old). Functional PRSs were associated with aggression in both the early and middle childhood models
Fast consensus clustering in complex networks
No full textAlgorithms for community detection are usually stochastic, leading to different partitions for different choices of random seeds. Consensus clustering has proven to be an effective technique to derive more stable and accurate partitions than the ones obtained by the direct application of the algorithm. However, the procedure requires the calculation of the consensus matrix, which can be quite dense if (some of) the clusters of the input partitions are large. Consequently, the complexity can get dangerously close to quadratic, which makes the technique inapplicable on large graphs. Here we present a fast variant of consensus clustering, which calculates the consensus matrix only on the links of the original graph and on a comparable number of additional node pairs, suitably chosen. This brings the complexity down to linear, while the performance remains comparable as the full technique. Therefore, our fast consensus clustering procedure can be applied on networks with millions of nodes and links
Recency predicts bursts in the evolution of author citations
No full textThe citations process for scientific papers has been studied extensively. But while the citations accrued by authors are the sum of the citations of their papers, translating the dynamics of citation accumulation from the paper to the author level is not trivial. Here we conduct a systematic study of the evolution of author citations, and in particular their bursty dynamics. We find empirical evidence of a correlation between the number of citations most recently accrued by an author and the number of citations they receive in the future. Using a simple model where the probability for an author to receive new citations depends only on the number of citations collected in the previous 12-24 months, we are able to reproduce both the citation and burst size distributions of authors across multiple decades