Personal exposure monitoring of PM among US diplomats in Kathmandu during the COVID-19 lockdown, March to June 2020.

The 2019 Novel Coronavirus SARS-CoV 2 (COVID-19) pandemic has severely impacted global health, safety, economic development and diplomacy. The government of Nepal issued a lockdown order in the Kathmandu Valley for 80 days from 24 March to 11 June 2020. This paper reports associated changes in ambient PM measured at fixed-site monitors and changes in personal exposure to PM monitored by APT Minima by four American diplomats who completed monitoring before and during lockdown (24 h for each period per person, 192 person-hours in total).

Deployment of networked low-cost sensors and comparison to real-time stationary monitors in New Delhi.

Air quality is a global challenge issue, and many regions of the world, such as India, are experiencing daunting challenges. An important aspect is to identify and then control the emissions from major contributing sources. To advance this aspect, this paper describes an air quality network that has been set up in the National Capital Territory of Delhi (NCT-Delhi) to identify major contributing source categories in real-time.

Photochemically assisted fast abiotic oxidation of manganese and formation of δ-MnO nanosheets in nitrate solution.

This study introduces a new and previously unconsidered fast abiotic formation of Mn(iv) oxides. We report photochemically assisted fast abiotic oxidation of Mn (aq) to Mn(iv) (s) by superoxide radicals generated from nitrate photolysis. This photochemical pathway generates randomly stacked layered birnessite (δ-MnO) nanosheets.

Non-invasive aerosol delivery and transport of gold nanoparticles to the brain.

Targeted delivery of nanoscale carriers containing packaged payloads to the central nervous system has potential use in many diagnostic and therapeutic applications. Moreover, understanding of the bio-interactions of the engineered nanoparticles used for tissue-specific delivery by non-invasive delivery approaches are also of paramount interest. Here, we have examined this issue systematically in a relatively simple invertebrate model using insects.

Carbon elimination from silicon kerf: Thermogravimetric analysis and mechanistic considerations.

40% of ultrapure silicon is lost as kerf during slicing to produce wafers. Kerf is currently not being recycled due to engineering challenges and costs associated with removing its abundant impurities. Carbon left behind from the lubricant remains as one of the most difficult contaminants to remove in kerf without significant silicon oxidation.

Directed assembly of the thylakoid membrane on nanostructured TiO2 for a photo-electrochemical cell.

The thylakoid membrane mainly consists of photosystem I (PSI), photosystem II (PSII) and the cytochrome b6f embedded in a lipid bilayer. PSI and PSII have the ability to capture sunlight and create an electron-hole pair. The study aims at utilizing these properties by using the thylakoid membrane to construct a photo-electrochemical cell.

Linker-free deposition and adhesion of Photosystem I onto nanostructured TiO2 for biohybrid photoelectrochemical cells.

Photosystem I (PSI) from oxygenic photosynthetic organisms is an attractive sensitizer for nano-biohybrid solar cells as it has a combined light-harvesting and reaction center in one protein complex and operates at a quantum yield close to one in biological systems. Using a linker-free deposition technique enabled by an electrospray system, PSI was coupled to 1-D nanostructured titanium dioxide thin films to fabricate an electrode for a photoelectrochemical cell. After deposition, the surfactant in the PSI aggregate was dissolved in the surfactant-free electrolyte, ensuring that partly hydrophobic PSI was not resuspended and stayed in contact with titanium dioxide.

Measurement of sub-2 nm clusters of pristine and composite metal oxides during nanomaterial synthesis in flame aerosol reactors.

Measuring stable clusters to understand particle inception will aid the synthesis of well-controlled nanoparticles via gas-phase aerosol routes. Using a Half Mini differential mobility analyzer, the presence of monomers, dimers, trimers, and tetramers was detected for the first time in a flame aerosol reactor during the synthesis of pristine TiO2 and TiO2/SiO2 nanocomposites. Atomic force microscopy confirmed the presence and the size of sub-2 nm clusters.

Study of the charge distribution on liposome particles aerosolized by air-jet atomization.

Background: Air-jet atomization is a common technique used for the generation of therapeutic aerosols from liposome suspensions for drug delivery to the lungs. Although the technique does not use an electric field, the aerosols generated by this technique are still charged, and this may affect respiratory drug deposition.

Methods: In this study, the charge distribution of liposomes aerosolized by an air-jet atomizer was measured using a tandem differential mobility analyzer (TDMA) technique.