Racial/ethnic and income disparities in neighborhood-level broadband access in 905 US cities, 2017-2021.

OBJECTIVES: Broadband access is an essential social determinant of health, the importance of which was made apparent during the COVID-19 pandemic. We sought to understand disparities in broadband access within cities and identify potential solutions to increase urban access. STUDY DESIGN: This was a descriptive secondary analysis using multi-year cross-sectional survey data. METHODS: Data were obtained from the City Health Dashboard and American Community Survey. We studied broadband access in 905 large US cities, stratifying neighborhood broadband access by neighborhood median household income and racial/ethnic composition. RESULTS: In 2017, 30% of urban households across 905 large US cities did not have access to high-speed broadband internet. After controlling for median household income, broadband access in majority Black and Hispanic neighborhoods was 10-15% lower than in majority White or Asian neighborhoods. Over time, lack of broadband access in urban households decreased from 30% in 2017 to 24% in 2021, but racial and income disparities persisted. CONCLUSIONS: As an emerging social determinant, broadband access impacts health across the life course, affecting students' ability to learn and adults' ability to find and retain jobs. Resolving lack of broadband access remains an urban priority. City policymakers can harness recent infrastructure funding opportunities to reduce broadband access disparities.

Influence of peptone source on sporulation of Clostridium perfringens type A.

Clostridium perfringens is a foodborne disease agent that produces a sporulation-specific enterotoxin. To produce enterotoxin for experimental purposes or spores for challenge or physiological studies, the use of a convenient sporulation medium is required. The most commonly used is Duncan-Strong medium. Few isolates sporulate at high levels in this medium. We investigated the effectiveness of peptones from a variety of sources on the sporulation of this organism compared with the peptone in the original formulation, proteose peptone (control). Seven strains were used to screen 32 peptones, with starch or raffinose as the carbohydrate source. In most cases, raffinose was more effective than starch in stimulating sporulation, confirming our previous study. Two promising peptones, potato peptone, and Proteose Peptone no. 3, were selected and tested against 49 additional enterotoxin-positive and -negative strains, with raffinose as the carbohydrate. For 49 strains, 5 sporulated best (>10%) in the control peptone, 6 sporulated best in Peptone no. 3, and 23 sporulated best in the potato peptone. Of the 23 strains, 16 sporulated at levels 25% more than the control peptone. The increase in sporulation rates was reflected in the enterotoxin and heat-resistant spore levels. The methylxanthines caffeine and theobromine were effective in increasing the sporulation of less than half of 19 enterotoxin-positive strains. Our results suggest that the replacement of proteose peptone with potato peptone be considered if difficulty in obtaining spores of specific strains of C. perfringens is encountered.

The Xylum Clot Signature Analyzer: a dynamic flow system that simulates vascular injury.

The Xylum Clot Signature Analyzer (CSA) is an automated, user-friendly, benchtop analyzer that assesses platelet function and coagulation in non-anticoagulated whole blood under physiological flow and temperature conditions. From blood drawn in a single venipuncture, the CSA measures: a) the time for platelets to occlude holes "punched" in a blood conduit (platelet hemostasis time or PHT); b) collagen-induced thrombus formation (CITF) as blood flows in a channel containing a collagen fiber; and c) clotting time (CT). Micrographs show platelet-rich thrombi in the punched holes and on the collagen surface after a run. PHT and CITF increased at lower shear rate, suggesting that shear activation of platelets is involved in hole closure and in collagen-induced thrombus formation. In blood mixed with anti-von Willebrand's factor (vWF) antibodies, anti-GPIb antibodies, aurin tricarboxylic acid (ATA), or anti-GPIIb-IIIa, PHT and CITF were prolonged, further supporting the reflection of platelet function by those parameters. At low shear rate (<1000 sec(-1)), native blood and blood treated with anti-vWF did not have significantly different PHTs or CITFs. At high shear rate (>6000 sec(-1)), the PHT and CITF of the anti-vWF-treated sample were significantly greater than those of the untreated sample. This supports the inhibition of shear-induced activation of platelets by anti-vWF in the CSA. Heparin-treated blood showed significantly longer CT, indicating that coagulation of blood under flow is inhibited by heparin. The CSA thus assess multiple aspects of hemostasis under near-physiological conditions.

Auditory effects of aircraft noise on people living near an airport.

Two groups of randomly chosen individuals who lived in two communities located different distances from the airport were studied. We monitored audiometry and brainstem auditory-evoked potentials to evaluate cochlear and retrocochlear functions in the individuals studied. The results of audiometry measurements indicated that hearing ability was reduced significantly in individuals who lived near the airport and who were exposed frequently to aircraft noise. Values of pure-tone average, high pure-tone average, and threshold at 4 kHz were all higher in individuals who lived near the airport, compared with those who lived farther away. With respect to brainstem auditory-evoked potentials, latencies between the two groups were not consistently different; however, the abnormality rate of such potentials was significantly higher in volunteers who lived near the airport, compared with less-exposed counterparts. In addition, a positive correlation was found between brainstem auditory-evoked potential latency and behavioral hearing threshold of high-frequency tone in exposed volunteers. We not only confirmed that damage to the peripheral cochlear organs occurred in individuals exposed frequently to aircraft noise, but we demonstrated involvement of the central auditory pathway.