Quantitatively comparing weekly changes in retinal vascular characteristics of eyes eventually treated versus not treated for retinopathy of prematurity

Purpose To quantitatively compare retinal vascular characteristics over time in eyes eventually treated versus not treated for retinopathy of prematurity (ROP), using ROPtool analysis of narrow-field retinal images. Methods This longitudinal study used prospectively collected narrow-field retinal images of infants screened for ROP, prior to treatment, if needed. Images were analyzed using a methodology that combines quadrant-level measures from several images of the same eye. For the longitudinal analysis, one examination per postmenstrual age (PMA) was included per eye. We compared the following ROPtool indices and their change per week between eyes eventually treated versus not treated for ROP: tortuosity index (TI), dilation index (DI), sum of adjusted indices (SAI), and tortuosity-weighted plus (TWP). Analysis was performed on three levels: eye (mean value/eye), quadrant (highest quadrant value/eye), and blood vessel (highest blood vessel value/eye). Results Of 832 examinations (99 infants), 745 images (89.5%) had 3-4 quadrants analyzable by ROPtool. On the eye level, ROPtool indices differed between eyes eventually treated versus not treated at PMA of 33-35 and 37 weeks for TI, SAI, and TWP, and at PMA of 33-34 and 37 weeks for DI (P ≤ 0.0014), and change per week differed between eyes eventually treated versus not treated only for SAI at PMA of 32 weeks (P < 0.001). Conclusions Quantitative analysis of retinal vascular characteristics using ROPtool can help predict eventual need for treatment for ROP as early as 32 weeks PMA. ROPtool index values were more useful than change in these indices to predict eyes that would eventually need treatment for ROP

Analysis of accumulated SARS-CoV-2 seroconversion in North Carolina: The COVID-19 Community Research Partnership

INTRODUCTION: The COVID-19 Community Research Partnership is a population-based longitudinal syndromic and sero-surveillance study. The study includes over 17,000 participants from six healthcare systems in North Carolina who submitted over 49,000 serology results. The purpose of this study is to use these serology data to estimate the cumulative proportion of the North Carolina population that has either been infected with SARS-CoV-2 or developed a measurable humoral response to vaccination. METHODS: Adult community residents were invited to participate in the study between April 2020 and February 2021. Demographic information was collected and daily symptom screen was completed using a secure, HIPAA-compliant, online portal. A portion of participants were mailed kits containing a lateral flow assay to be used in-home to test for presence of anti-SARS-CoV-2 IgM or IgG antibodies. The cumulative proportion of participants who tested positive at least once during the study was estimated. A standard Cox proportional hazards model was constructed to illustrate the probability of seroconversion over time up to December 20, 2020 (before vaccines available). A separate analysis was performed to describe the influence of vaccines through February 15, 2021. RESULTS: 17,688 participants contributed at least one serology result. 68.7% of the population were female, and 72.2% were between 18 and 59 years of age. The average number of serology results submitted per participant was 3.0 (±1.9). By December 20, 2020, the overall probability of seropositivity in the CCRP population was 32.6%. By February 15, 2021 the probability among healthcare workers and non-healthcare workers was 83% and 49%, respectively. An inflection upward in the probability of seropositivity was demonstrated around the end of December, suggesting an influence of vaccinations, especially for healthcare workers. Among healthcare workers, those in the oldest age category (60+ years) were 38% less likely to have seroconverted by February 15, 2021. CONCLUSIONS: Results of this study suggest more North Carolina residents may have been infected with SARS-CoV-2 than the number of documented cases as determined by positive RNA or antigen tests. The influence of vaccinations on seropositivity among North Carolina residents is also demonstrated. Additional research is needed to fully characterize the impact of seropositivity on immunity and the ultimate course of the pandemic

Computational Design of Enone-Binding Proteins with Catalytic Activity for the Morita–Baylis–Hillman Reaction

The Morita–Baylis–Hillman reaction forms a carbon–carbon bond between the α-carbon of a conjugated carbonyl compound and a carbon electrophile. The reaction mechanism involves Michael addition of a nucleophile catalyst at the carbonyl β-carbon, followed by bond formation with the electrophile and catalyst disassociation to release the product. We used Rosetta to design 48 proteins containing active sites predicted to carry out this mechanism, of which two show catalytic activity by mass spectrometry (MS). Substrate labeling measured by MS and site-directed mutagenesis experiments show that the designed active-site residues are responsible for activity, although rate acceleration over background is modest. To characterize the designed proteins, we developed a fluorescence-based screen for intermediate formation in cell lysates, carried out microsecond molecular dynamics simulations, and solved X-ray crystal structures. These data indicate a partially formed active site and suggest several clear avenues for designing more active catalysts

Enemies with benefits? Violent rivalry and terrorist group longevity

Terrorist organizations often attack each other, but we know little about how this affects the involved groups. Some states encourage or turn a blind eye toward terrorist group interorganizational violence, hoping that it destroys at least one of the groups involved. This article argues that – contrary to the wishes of such governments – violent rivalries can contribute to the longevity of participating terrorist groups. Violent rivalries encourage civilians to take a side, inspire innovation, provide new incentives to group members, and spoil peace talks. Some of these mechanisms should be especially likely between rivals of different political goals (interfield rivalries), instead of between rivals seeking the same primary goal (intrafield rivalries). Illustrative cases in Colombia and Northern Ireland show that the theorized mechanisms occur in diverse environments. Quantitative global analysis of terrorist groups from 1987 to 2005, using original data on interorganizational violence, suggests that violent rivalries are generally associated with group longevity. Further analysis suggests that when rivalries are disaggregated by type, only interfield rivalries are positively associated with group longevity. Participation in violent rivalry is never found to increase a group’s chance of ending. The results suggest the importance of studying interorganizational dynamics, and raise questions about the notion of encouraging a violent rivalry as a way to hurt an involved terrorist group