Atmospheric Particles and Their Effects on Cloud Formation and Climate

Under humid atmospheric conditions, pollen grains can rupture creating pollen grain fragments referred to as subpollen particles (SPPs). This study evaluated environmental conditions needed to emit SPPs and measure the concentration of SPPs produced. Conventional SPP release was considered where live oak branches were exposed to high relative humidity (>95%), followed by reduced relative humidity (73.5%-76.3%) and wind (up to 1.8 m s^-1). In contrast, wind-driven SPP release experiments were conducted by exposing branches to constant relative humidity and wind. Wind-driven SPP release was the mechanism considered for subsequent experiments. SPP emission factors were determined for wind-driven SPP release for live oak, Quercus virginiana, ryegrass, Lolium sp., and giant ragweed, Ambrosia trifida, in terms of SPPs produced per pollen grain and SPPs produced per m^2. The SPPs produced per m^2 were 1.1x10^15 ± 1.6x10^15 for live oak, 4.9x10^13 ± 4.3x10^13 for ryegrass, and 1.3x10^15 ± 1.1x10^15 for giant ragweed. SPPs and pollen grains from these species were evaluated for their ice nucleation efficiency in immersion and contact mode freezing. Measurements indicate that SPPs are weakly effective INPs in immersion mode, but that pollen grains represent a source of moderately efficient INPs in immersion and contact modes. Additionally, viscous solution droplets were tested for their ability to contribute to homogeneous freezing and ice cloud formation. In this study, viscosity was determined for aqueous organic solutions (citric acid, sucrose, maltose, glyoxal, and methylglyoxal) at varying weight percent (40%, 50%, and 65%), saturated solutions, and three eutonic solutions. In high viscosity droplets, the time required for initial onset of freezing was increased to 4.4±3.9 hours and 5.2±4.1 hours for complete freezing at a temperature of -40 °C. While low viscosity droplets had onset freezing as quickly as 1.9±2.2 hours and complete freezing in 2.6±4.0 hours at a temperature of -40 °C. Given the timescales of freezing observed here, the phase of aerosol containing high concentrations of organic compounds will depend on updraft velocity. Overall, our measurements suggest aerosol containing high concentrations of organic compounds will be present as supercooled liquids in the upper troposphere

Strategies for engaging Black male caregivers in family-based research

Black men are less likely to participate in research studies due to historical abuses and mistrust, which has consequences for various health issues, including research to improve the sexual health and well-being of young girls and women. This paper aims to present strategies from research staff on how to engage Black male caregivers in family-based research. After our five Black research team members (i.e., researchers, recruiters, facilitators, and community liaisons) recruited 30 Black male caregivers into one-on-one interviews, ten into focus groups, six into theatre testing of an intervention, and 20 more into the pilot intervention, interviews explored their experiences engaging the targeted population in research. Interview questions included asking what strategies were successful, what challenges occurred, and future recommendations to engage Black male caregivers in research. Audio recordings and written response data were analyzed using thematic analysis. Themes included: 1) empowering Black communities through fatherhood initiatives, 2) utlizing culturally sensitive and respectful recruiters, 3) highlighting the value of Black men, and 4) implementing study materials enhancing positive representations of Black men. Implementing strategies to include Black men in family-based health research has the potential to reduce health disparities in the United States and increase their representation across the literature. These strategies will equip researchers to engage in research with minority and structurally-systemically disadvantaged groups

Group B Streptococcus-Induced Macropinocytosis Contributes to Bacterial Invasion of Brain Endothelial Cells

Bacterial meningitis is defined as serious inflammation of the central nervous system (CNS) in which bacteria infect the blood–brain barrier (BBB), a network of highly specialized brain endothelial cells (BECs). Dysfunction of the BBB is a hallmark of bacterial meningitis. Group B Streptococcus (GBS) is one of the leading organisms that cause bacterial meningitis, especially in neonates. Macropinocytosis is an actin-dependent form of endocytosis that is also tightly regulated at the BBB. Previous studies have shown that inhibition of actin-dependent processes decreases bacterial invasion, suggesting that pathogens can utilize macropinocytotic pathways for invasion. The purpose of this project is to study the factors that lead to dysfunction of the BBB. We demonstrate that infection with GBS increases rates of endocytosis in BECs. We identified a potential pathway, PLC-PKC-Nox2, in BECs that contributes to macropinocytosis regulation. Here we demonstrate that downstream inhibition of PLC, PKC, or Nox2 significantly blocks GBS invasion of BECs. Additionally, we show that pharmacological activation of PKC can turn on macropinocytosis and increase bacterial invasion of nonpathogenic yet genetically similar Lactococcus lactis. Our results suggest that GBS activates BEC signaling pathways that increase rates of macropinocytosis and subsequently the invasion of GBS

T2 Protect AD: Achieving a rapid recruitment timeline in a multisite clinical trial for individuals with mild to moderate Alzheimer's disease.

IntroductionThe reporting of approaches facilitating the most efficient and timely recruitment of Alzheimer's disease (AD) patients into pharmacologic trials is fundamental to much-needed therapeutic progress.MethodsT2 Protect AD (T2), a phase 2 randomized placebo-controlled trial of troriluzole in mild to moderate AD, used multiple recruitment strategies.ResultsT2 exceeded its recruitment target, enrolling 350 participants between July 2018 and December 2019 (randomization rate: 0.87 randomizations/site/month, or 3-fold greater than recent trials of mild to moderate AD). The vast majority (98%) of participants were enrolled during a 10-month window of intense promotion in news media, TV and radio advertisements, and social media. The distribution of primary recruitment sources included: existing patient lists at participating sites (72.3%), news media (12.3%), physician referral (6.0%), word of mouth (3.1%), and paid advertising (2.9%).DiscussionThe rapid recruitment of participants with mild to moderate AD was achieved through a range of approaches with varying success

T2 Protect AD: Achieving a rapid recruitment timeline in a multisite clinical trial for individuals with mild to moderate Alzheimer's disease

Abstract Introduction The reporting of approaches facilitating the most efficient and timely recruitment of Alzheimer's disease (AD) patients into pharmacologic trials is fundamental to much‐needed therapeutic progress. Methods T2 Protect AD (T2), a phase 2 randomized placebo‐controlled trial of troriluzole in mild to moderate AD, used multiple recruitment strategies. Results T2 exceeded its recruitment target, enrolling 350 participants between July 2018 and December 2019 (randomization rate: 0.87 randomizations/site/month, or 3‐fold greater than recent trials of mild to moderate AD). The vast majority (98%) of participants were enrolled during a 10‐month window of intense promotion in news media, TV and radio advertisements, and social media. The distribution of primary recruitment sources included: existing patient lists at participating sites (72.3%), news media (12.3%), physician referral (6.0%), word of mouth (3.1%), and paid advertising (2.9%). Discussion The rapid recruitment of participants with mild to moderate AD was achieved through a range of approaches with varying success