ABSTRACT
This study investigated upper-room germicidal ultraviolet (UR-GUV) light application in a music rehearsal room with a high ceiling (7.5 m). The focus was on the influences of the elevation and height of UV zone on disinfection of airborne viruses. This study assumed a uniform UV fluence rate of 0.2 W/m2 in the UV irradiation zone. According to the Computational Fluid Dynamics (CFD) results, average viral concentrations (Ca), fraction remaining (FR), and equivalent air exchange rate (λe) attributed to GUV, have power relationships with UV zone height. Ca and FR decreased with UV zone height, while λe did the opposite. UV zone elevation showed little influence on UR-GUV performance, indicating well-mixed air in the rehearsal room. High ceiling makes it possible to achieve adequate UV dose by increasing both UV zone height and UV light intensity. Using open fixtures improved energy efficiency and reduced operational costs of the UR-GUV system. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.
ABSTRACT
The outbreak of COVID-19 pandemic in northern Taiwan led to the implementation of Level 3 alert measures during 2021 and thereby impacted the air quality significantly, which provided an unprecedented opportunity to better understand the control strategies on air pollutants in the future. This study investigated the variations in sources, chemical characteristics and human health risks of PM2.5 comprehensively. The PM2.5 mass concentrations decreased from pre-alert to Level 3 alert by 49.4%, and the inorganic ions, i.e., NH4+, NO3- and SO42-, dropped even more by 71%, 90% and 52%, respectively. Nonetheless, organic matter (OM) and elemental carbon (EC) simply decreased by 36% and 13%, which caused the chemical composition of PM2.5 to change so that the carbonaceous matter in PM2.5 dominated instead of the inorganic ions. Correlation-based hierarchical clustering analysis further showed that PM2.5 was clustered with carbonaceous matter during the Level 3 alert, while that clustered with inorganic ions during both pre-alert and post-alert periods. Moreover, 6 sources of PM2.5 were identified by positive matrix factorization (PMF), in which secondary nitrate (i.e., aging traffic aerosols) exhibited the most significant decrease and yet primary traffic-related emissions, dominated by carbonaceous matter, changed insignificantly. This implied that secondary traffic-related aerosols could be easily controlled when traffic volume declined, while primary traffic source needs more efforts in the future, especially for the reduction of carbonaceous matter. Therefore, cleaner energy for vehicles is still needed. Assessments of both carcinogenic risk and non-carcinogenic risk induced by the trace elements in PM2.5 showed insignificant decrease, which can be attributed to the factories that did not shut down during Level 3 alert. This study serves as a metric to underpin the mitigation strategies of air pollution in the future and highlights the importance of carbonaceous matter for the reduction in PM2.5.
ABSTRACT
Background: ALG-000184 is a prodrug of ALG-001075, a novel, potent, pan-genotypic Class II CAM. CAMs are thought to have two mechanisms of action (MoA). The primary MoA affects pgRNA encapsidation resulting in inhibition of HBV DNA/RNA replication, as confirmed in CHB subjects receiving ALG-000184. The secondary MoA, which occurs at higher concentrations, regulates the establishment and replenishment of cccDNA, resulting in lowering of HBsAg, an effect that has not been reported to date with ALG- 000184. Method(s): ALG-000184-201 is a multi-part, multicenter, doubleblind, randomized, placebo-controlled study. In healthy volunteers (HVs), single doses up to 500 mg and multiple doses up to 250 mg were well tolerated with linear PK (Gane E., HBV TAG and APASL 2021). In treatment naive (TN) subjects with CHB, daily oral doses of 10-100 mg ALG-000184 for 28 days were well tolerated with linear PK and were associated with profound reductions of DNA/RNA regardless of HBeAg status or dose (Yuen MF, EASL 2022). Plasma exposures required to engage the secondary MoA are expected to be achieved at the 300 mg dose level. Data from a 300 mg cohort treated for 28 days are described here. Data from another ongoing cohort treated with 300 mg for 12 weeks will be presented at the conference. Result(s): Ten subjects were randomized to 300 mg ALG-000184 for 28 days and two to placebo. Two subjects randomized to ALG- 000184 were replaced due to missing data due to Covid-19 lockdown. Subjects were Asian, HBeAg positive, and genotype B or C. Mean baseline HBV DNA and RNA levels were 8.4 log10 IU/mL and 7.3 log10 copies/mL, respectively. One subject experienced a serious adverse event (AE) of pneumothorax>8 weeks after last dose which was considered unlikely related to study drug. No subjects prematurely discontinued study drug. All treatment emergent AEs were Grade <= 2 except for 4 Grade >= 3 alanine aminotransferase (ALT) elevations, which an independent ALT Flare Committee assessed as not related to study drug toxicity. PK was similar to HBeAg negative and HV cohorts following body weight adjustment. Subjects dosed with 300 mg ALG-000184 experienced mean declines of 4.0 log10 IU/mL and 2.6 log10 copies/mL in HBV DNA and RNA levels, respectively, at Day 28. Three of 7 evaluable subjects who received ALG-000184 had HBsAg declines>0.2 log10 IU/mL (0.23-0.78 log10 IU/mL). One subject receiving ALG-000184 had unquantifiable HBsAg throughout the study. Additionally, one HBeAg positive subject in a prior 100 mg cohort had plasma exposures equivalent to the 300 mg dose level and experienced a 0.5 log10 IU/mL HBsAg decline. Conclusion(s): In TN HBeAg positive CHB subjects, 300 mg ALG- 000184 for 28 days was well tolerated, exhibited predictable PK and resulted in rapid and substantial declines in HBV DNA and RNA. Notably, 3 of 7 evaluable subjects from this cohort experienced HBsAg declines of up to 0.78 log10 IU/mL. These data suggest that ALG-000184 can engage the secondary MoA of CAM II. Cohorts evaluating 300 mg over longer durations are planned or ongoing.