Genome-wide high-resolution mapping of UV-induced mitotic recombination events in Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae and most other eukaryotes, mitotic recombination is important for the repair of double-stranded DNA breaks (DSBs). Mitotic recombination between homologous chromosomes can result in loss of heterozygosity (LOH). In this study, LOH events induced by ultraviolet (UV) light are mapped throughout the genome to a resolution of about 1 kb using single-nucleotide polymorphism (SNP) microarrays. UV doses that have little effect on the viability of diploid cells stimulate crossovers more than 1000-fold in wild-type cells. In addition, UV stimulates recombination in G1-synchronized cells about 10-fold more efficiently than in G2-synchronized cells. Importantly, at high doses of UV, most conversion events reflect the repair of two sister chromatids that are broken at approximately the same position whereas at low doses, most conversion events reflect the repair of a single broken chromatid. Genome-wide mapping of about 380 unselected crossovers, break-induced replication (BIR) events, and gene conversions shows that UV-induced recombination events occur throughout the genome without pronounced hotspots, although the ribosomal RNA gene cluster has a significantly lower frequency of crossovers

High-resolution mapping of heteroduplex DNA formed during UV-induced and spontaneous mitotic recombination events in yeast.

In yeast, DNA breaks are usually repaired by homologous recombination (HR). An early step for HR pathways is formation of a heteroduplex, in which a single-strand from the broken DNA molecule pairs with a strand derived from an intact DNA molecule. If the two strands of DNA are not identical, there will be mismatches within the heteroduplex DNA (hetDNA). In wild-type strains, these mismatches are repaired by the mismatch repair (MMR) system, producing a gene conversion event. In strains lacking MMR, the mismatches persist. Most previous studies involving hetDNA formed during mitotic recombination were restricted to one locus. Below, we present a global mapping of hetDNA formed in the MMR-defective mlh1 strain. We find that many recombination events are associated with repair of double-stranded DNA gaps and/or involve Mlh1-independent mismatch repair. Many of our events are not explicable by the simplest form of the double-strand break repair model of recombination

On-Board Sensor-Based NO x Emissions from Heavy-Duty Diesel Vehicles

Real-world nitrogen oxides (NOx) emissions were estimated using on-board sensor readings from 72 heavy-duty diesel vehicles (HDDVs) equipped with a Selective Catalytic Reduction (SCR) system in California. The results showed that there were large differences between in-use and certification NOx emissions, with 12 HDDVs emitting more than three times the standard during hot-running and idling operations in the real world. The overall NOx conversion efficiencies of the SCR system on many vehicles were well below the 90% threshold that is expected for an efficient SCR system, even when the SCR system was above the optimum operating temperature threshold of 250 °C. This could potentially be associated with SCR catalyst deterioration on some engines. The Not-to-Exceed (NTE) requirements currently used by the heavy-duty in-use compliance program were evaluated using on-board NOx sensor data. Valid NTE events covered only 4.2–16.4% of the engine operation and 6.6–34.6% of the estimated NOx emissions. This work shows that low cost on-board NOx sensors are a convenient tool to monitor in-use NOx emissions in real-time, evaluate the SCR system performance, and identify vehicle operating modes with high NOx emissions. This information can inform certification and compliance programs to ensure low in-use NOx emissions

Advancing Accessibility Research in Kinesiology: A Mixed-Methods Case Study of One Survey Website

While some studies in kinesiology have investigated the accessibility of educational material and electronic applications used to promote physical activity (eg, ease to perceive/navigate content resources), few studies report on the accessibility of survey tools before their use in research. PURPOSE: The purpose of this study was to measure the accessibility of one survey website to a study directly investigating comprehension of mock physical activity promotion material created by Thomas et al. (2023). METHODS: The website was for study participants to complete an online version of a cloze form (for a visual, see Nielsen, 2011; eg, see Cardinal et al., 1995). The accessibility check, done before the research website launched, had two phases: (1) a valid and reliable quantitative accessibility rating form was administered by the research team (Jul - Aug 2022, Wu et al. 2022a & 2022b) and (2) after edits were made based on the rating form findings, a pilot test of the website survey instruments was done with mock end users (Feb - Mar 2023). Mock end users (n = 12) were volunteers from the first author’s research lab and were invited to give qualitative feedback on the site’s usability before leaving the website (eg, on webpage/site navigation, on instruction clarity). Ten gave website feedback. The analytic plan was to (1) identify descriptive trends in the mock end user feedback (2) relate feedback trends to rating form criteria scores with unanimous consensus, as a measure of similarity between the two study findings (ie, Phase 1 vs 2). RESULTS: Phase 1 data analysis suggested each webpage fully met accessibility standards in 7 subareas (eg, plain language use, clear navigation). Phase 2 analysis supported most conclusions derived from rating form results (eg, clear instructions & layout), but challenged others (eg, cloze form was somewhat accessible because website platform, Canvas, required scrolling once finished, not due to missing frequently asked questions page). Pilot test showed text at a lower reading level (before edits) had lower comprehension, but text at a higher level had good validity. CONCLUSION: Our results evidenced the rating form could ensure websites have adequate accessibility. Findings also underscored significance of pilot testing research instruments with mock end users outside the research team

Low-Loss Plasmonic Dielectric Nanoresonators

Material losses in metals are a central bottleneck in plasmonics for many applications. Here we propose and theoretically demonstrate that metal losses can be successfully mitigated with dielectric particles on metallic films, giving rise to hybrid dielectric-metal resonances. In the far field, they yield strong and efficient scattering, beyond even the theoretical limits of all-metal and all-dielectric structures. In the near field, they offer high Purcell factor (>5000), high quantum efficiency (>90%), and highly directional emission at visible and infrared wavelengths. Their quality factors can be readily tailored from plasmonic-like (∼10) to dielectric-like (∼103), with wide control over the individual resonant coupling to photon, plasmon, and dissipative channels. Compared with conventional plasmonic nanostructures, such resonances show robustness against detrimental nonlocal effects and provide higher field enhancement at extreme nanoscopic sizes and spacings. These hybrid resonances equip plasmonics with high efficiency, which has been the predominant goal since the field’s inception. Keywords: light scattering; nanoantennas; Nanoparticles; nonlocality; radiative efficiency; spontaneous emissionUnited States. Army Research Office (Contract W911NF-13-D-0001)National Science Foundation (U.S.) (Grant DMR-1419807)United States. Department of Energy (Grant DE-SC0001299

Evaluating Research Survey Websites in Kinesiology: A Case Study Using An Accessibility Rating Form

Advancing equity in the research and educational practice of kinesiology requires intentional efforts to ensure access divides do not widen nor persist (Ross et al., in press, JOPERD). PURPOSE: Given knowledge of suitability assessment of materials (SAM) principles supports the equitable design of lay print and online material, we evaluated the extent they would also support developing a research survey website consistent with accessibility guidelines for digital technology. METHODS: The study website was adapted from the Canvas learning management system. A cross-sectional formative assessment was performed. Using their knowledge of SAM principles (eg, clear layout, text ≤ 8th grade reading level), the second and third author (JDT, RFH) constructed the website webpages (eg, site welcome page, online questionnaire; Jun.-Jul. 2022). The first author (YSW), using guidelines from two reputable sources (ie, a Canvas tutorial and W3C website), developed a 14-item accessibility rating form to critically appraise the website’s 10 webpages (ie, 1 = Not Accessible, 2 = Somewhat Accessible, 3 = Accessible; Wallace et al., 2010, JPAH). Authors 1-4 then performed a formative assessment of the adapted Canvas websites’ accessibility independently (Jul.-Aug. 2022). Form reliability was assessed using the intraclass correlation coefficient and its interpretive cut-points for average absolute-rater agreement (Cicchetti, 1994, Psych Assess; Landers, 2015, Winnower). RESULTS: Average rater agreement was excellent per webpage (M = .91, LL = .82, UL = .94). Mean webpage score ranged between 2.55 (±0.78) to 2.77 (±0.58). Informational pages (eg, welcome page) had greater accessibility than interactive pages (eg, forms). Five discrepant items were systematic, resulting in redundant rater differences (eg, keyboard navigation was hard to notice). All discrepancies were resolved with 100% consensus. CONCLUSION: The findings of the present study suggest knowledge of SAM principles ensures developers can design lay friendly and accessible research survey websites. They further suggest rating forms inclusive of digital accessibility guidelines should be used as a supplement to further meet accessibility and equity goals. We will share our form, then discuss our results using the universal design for learning framework