pores with an average diameter of 173 nm were formed on the surface of WO3 NTs due to decomposition of the PS colloids.In addition, catalytic Pd nanoparticles (NPs) were synthesized using bio-inspired protein cages, i.e., apoferritin, and uniformly dispersed within the shell solution and subsequently on the WO3 NTs. The resulting Pd-functionalized macroporous WO3 NTs were demonstrated to be high performance hydrogen (H2) sensors. In particular, Pd-funtionalized macroporous WO3 NTs exhibited a very high H2 response (Rair/Rgas) of 17.6 at 500 ppm with short response time.Furthermore, the NTs were shown to be highly selective for H2 compared to other gases such as carbon monoxide (CO), ammonia (NH3), and methane (CH4). The results demonstrate a new synthetic method to prepare highly porous nanotubular structure with well-dispersed nanoscale catalysts, which can provide improved microstructures for chemical sensing.
Aerosol filtration using electrospun cellulose acetate filters with different mean fiber diameters is reported, and the results are compared with those for two conventional filter media, a glass fiber filter and a cellulose acetate microfiber filter. The performance of these filters was studied using two aerosols, one solid (NaCl) and one liquid (diethyl hexyl sebacate, DEHS), under conditions of relatively high face velocity (45 cm/s). The experimental observations are compared to theoretical predictions based on single fiber filtration efficiency. Our results indicate that the mechanisms for single fiber filtration efficiency provide reasonable predictions of the most penetrating particle size (MPPS), in the range of 40-270 nm, percentage penetration from 0.03-70%, and fiber diameter in the range from 0.1-24 µm. Using an analysis based on blocking filtration laws, we conclude that filtration by cake formation dominated in the case of NaCl aerosols on electrospun filter media, whereas filters with larger fiber diameter showed a transition in mechanisms, from an initial regime characterized by pore blocking to a later regime characterized by cake formation. The liquid aerosol did not exhibit cake formation, even for the smallest fiber diameters, and also had much smaller influence on pressure drop than did the solid aerosol. The electrospun filters demonstrated slightly better quality factors compared to the commercial glass fiber filter, at a much lower thickness. In general this study demonstrates control of the properties of electrospun cellulose acetate fibers for air filtration application.
The
pharmaceutical industry faces multiple challenges (e.g., inefficient
manufacturing techniques, quality control issues, and supply chain
vulnerabilities) because of its current batch-wise approach to manufacturing.
Recent regulatory support for continuous manufacturing and advances
in continuous process technologies have caused an increase in interest
from some drug manufacturers to modernize their production processes.
However, many of these companies have focused on hybrid processes,
where only certain steps are continuous, while others remain batch.
Herein, the quality by design (QbD)-based design strategy and operation
of an end-to-end integrated continuous manufacturing (ICM) pilot plant
that produces both small-molecule active pharmaceutical ingredient
(API) and oral solid dosages (OSDs) are discussed. Additionally, important
quality and economic matters pertaining to scale-up and commercialization
are addressed. ICM has significant benefits, including better quality
control, increased supply chain flexibility, a lower capital investment
(in the example provided, a ∼ 90% reduction),
and lower operating costs (in the example provided, a 33.6% reduction
for API and 29.4% reduction for tablets).
Results showed that the atomized liposomes have a bipolar charge distribution, and the number-fraction of charged liposome aerosols was influenced strongly by properties of the precursor solution under investigation. Liposomes synthesized in deionized water were observed to carry much higher charges than those synthesized in phosphate-buffered saline (PBS). Increasing the lipid mass concentration in the precursor suspension resulted in a decrease in the charge on the aerosols. Thus, the precursor suspension properties--composition, pH, and conductivity--can be used to control the magnitude of charge on liposome aerosols and to synthesize engineered liposome particles for the pulmonary delivery of drugs with controlled alveolar deposition and controlled delivery to alveolar macrophages.
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