Evaluating the Performance of Low-Cost PM2.5 Sensors in Mobile Settings.

Low-cost sensors (LCSs) for measuring air pollution are increasingly being deployed in mobile applications, but questions concerning the quality of the measurements remain unanswered. For example, what is the best way to correct LCS data in a mobile setting? Which factors most significantly contribute to differences between mobile LCS data and those of higher-quality instruments? Can data from LCSs be used to identify hotspots and generate generalizable pollutant concentration maps? To help address these questions, we deployed low-cost PM2.5 sensors (Alphasense OPC-N3) and a research-grade instrument (TSI DustTrak) in a mobile laboratory in Boston, MA, USA. We first collocated these instruments with stationary PM2.5 reference monitors (Teledyne T640) at nearby regulatory sites. Next, using the reference measurements, we developed different models to correct the OPC-N3 and DustTrak measurements and then transferred the corrections to the mobile setting. We observed that more complex correction models appeared to perform better than simpler models in the stationary setting; however, when transferred to the mobile setting, corrected OPC-N3 measurements agreed less well with the corrected DustTrak data. In general, corrections developed by using minute-level collocation measurements transferred better to the mobile setting than corrections developed using hourly-averaged data. Mobile laboratory speed, OPC-N3 orientation relative to the direction of travel, date, hour-of-the-day, and road class together explain a small but significant amount of variation between corrected OPC-N3 and DustTrak measurements during the mobile deployment. Persistent hotspots identified by the OPC-N3s agreed with those identified by the DustTrak. Similarly, maps of PM2.5 distribution produced from the mobile corrected OPC-N3 and DustTrak measurements agreed well. These results suggest that identifying hotspots and developing generalizable maps of PM2.5 are appropriate use-cases for mobile LCS data.

Hyperlocal environmental data with a mobile platform in urban environments.

Environmental data with a high spatio-temporal resolution is vital in informing actions toward tackling urban sustainability challenges. Yet, access to hyperlocal environmental data sources is limited due to the lack of monitoring infrastructure, consistent data quality, and data availability to the public. This paper reports environmental data (PM, NO2, temperature, and relative humidity) collected from 2020 to 2022 and calibrated in four deployments in three global cities. Each data collection campaign targeted a specific urban environmental problem related to air quality, such as tree diversity, community exposure disparities, and excess fossil fuel usage. Firstly, we introduce the mobile platform design and its deployment in Boston (US), NYC (US), and Beirut (Lebanon). Secondly, we present the data cleaning and validation process, for the air quality data. Lastly, we explain the data format and how hyperlocal environmental datasets can be used standalone and with other data to assist evidence-based decision-making. Our mobile environmental sensing datasets include cities of varying scales, aiming to address data scarcity in developing regions and support evidence-based environmental policymaking.

Key Themes, Trends, and Drivers of Mobile Ambient Air Quality Monitoring: A Systematic Review and Meta-Analysis.

Mobile ambient air quality monitoring is rapidly changing the current paradigm of air quality monitoring and growing as an important tool to address air quality and climate data gaps across the globe. This review seeks to provide a systematic understanding of the current landscape of advances and applications in this field. We observe a rapidly growing number of air quality studies employing mobile monitoring, with low-cost sensor usage drastically increasing in recent years. A prominent research gap was revealed, highlighting the double burden of severe air pollution and poor air quality monitoring in low- and middle-income regions. Experiment-design-wise, the advances in low-cost monitoring technology show great potential in bridging this gap while bringing unique opportunities for real-time personal exposure, large-scale deployment, and diversified monitoring strategies. The median value of unique observations at the same location in spatial regression studies is ten, which can be used as a rule-of-thumb for future experiment design. Data-analysis-wise, even though data mining techniques have been extensively employed in air quality analysis and modeling, future research can benefit from exploring air quality information from nontabular data, such as images and natural language.

Expression and Purification of Porcine Rotavirus Structural Proteins in Silkworm Larvae as a Vaccine Candidate.

In this study, silkworm larvae were used for expression of porcine rotavirus A (KS14 strain) inner capsid protein, VP6, and outer capsid protein, VP7. Initially, VP6 was fused with Strep-tag II and FLAG-tag (T-VP6), and T-VP6 was fused further with the signal peptide of Bombyx mori 30k6G protein (30k-T-VP6). T-VP6 and 30 k-T-VP6 were then expressed in the fat body and hemolymph of silkworm larvae, respectively, with respective amounts of 330 µg and 50 µg per larva of purified protein. Unlike T-VP6, 30k-T-VP6 was N-glycosylated due to attached signal peptide. Also, VP7 was fused with PA-tag (VP7-PA). Additionally, VP7 was fused with Strep-tag II, FLAG-tag, and the signal peptide of Bombyx mori 30k6G protein (30k-T-ΔVP7). Both VP7-PA and 30k-T-ΔVP7 were expressed in the hemolymph of silkworm larvae, with respective amounts of 26 µg and 49 µg per larva of purified protein, respectively. The results from our study demonstrated that T-VP6 formed nanoparticles of greater diameter compared with the ones formed by 30k-T-VP6. Also, higher amount of VP6 expressed in silkworm larvae reveal that VP6 holds the potential for its use in vaccine development against porcine rotavirus with silkworm larvae as a promising host for the production of such multi-subunit vaccines.

Dynamic control of heat flow using a spin-chain ladder cuprate film and an ionic liquid.

Dynamic control of heat flow for applications in thermal management has attracted much interest in fields such as electronics and thermal engineering. Spin-chain ladder cuprates are promising materials to realize dynamic control of heat flow, since their magnon thermal conductivity is sensitive to the hole density in the spin ladders, which can be dynamically controlled by an external field. Here, we demonstrate the electric control of heat flow using a polycrystalline cuprate film and an ionic liquid. The results showed that a voltage application to the interface causes imperfectly recoverable decreases in both the thermal conductance of the film and the peak due to magnons in the Raman spectra. This result may be attributed to an increase in the hole density in the spin ladders. This report highlights that magnon thermal conduction has potential for the development of advanced thermal management applications.

Preparation of divalent antigen-displaying enveloped virus-like particles using a single recombinant Bombyx mori nucleopolyhedrovirus bacmid in silkworms.

Silkworms have been used as a host for the production of recombinant proteins in a baculovirus expression system using Bombyx mori nucleopolyhedrovirus (BmNPV). To coexpress several recombinant proteins, a silkworm must be coinfected with several recombinant BmNPVs, which requires a difficult DNA manipulation procedure. In this study, we constructed recombinant BmNPVs containing three expression cassettes, Rous sarcoma virus (RSV) Gag protein, surface antigen 1 of Neospora caninum (NcSAG1) and SAG1-related sequence 2 of N. caninum (NcSRS2), by Gibson assembly and the Bac-to-Bac system, designated BmNPV/SAG-SRS-Gag and BmNPV/SAG-Gag-SRS. BmNPV/SAG-SRS-Gag was expressed in silkworms and characterized. NcSAG1 and NcSRS2 were purified with RSV Gag proteins using sucrose density gradient centrifugation and affinity chromatography. RSV Gag formed virus-like particles (RSV-LPs) at a diameter of 20-30 nm based on transmission electron microscopy (TEM). Immuno-TEM analysis showed that both NcSAG1 and NcSRS2 were displayed on the surface of the RSV-LPs. These results indicate that RSV-LPs displaying two different kinds of proteins were produced in the hemolymph of silkworm larvae by the single polycistronic strategy. This expression platform is efficient for generating multiantigen-displaying VLPs and facilitates the development of vaccines against infectious diseases.