Assessment of novel antiviral filter using pseudo-type SARS-CoV-2 virus in fast air velocity vertical-type wind tunnel.

Current evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can remain suspended spread in aerosols for longer period of time under poorly ventilated indoor setting. To minimize spreading, application of antiviral filter to capture infectious aerosols and to inactivate SARS-CoV-2 can be a promising solution. This study aimed to develop a method to assess simultaneously the filtration and removal efficiency of aerosolized pseudo-type SARS-CoV-2 using a vertical-type wind tunnel with relatively high face velocity (1.3 m/s). Comparing with the untreated spunlace non-woven filter, the C-POLAR™ treated filter increased the filtration efficiency from 74.2 ± 11.5% to 97.2 ± 1.7%, with the removal efficiency of 99.4 ± 0.051%. The results provided not only solid evidence to support the effectiveness of the cationic polymeric coated filter in fighting against the SARS-CoV-2 pandemic, but also a method to test viral filtration and removal efficiency under relative fast air velocity and with a safer environment to the operators.

Quantitative analysis and risk assessment to full-size microplastics pollution in the coastal marine waters of Hong Kong.

Given the potential risk to the ecosystem, attention has increased in recent decades to the contamination of the aquatic environment by microplastics (MPs). Due to the limitations of conventional analysis methods of MPs, little is known about the size distribution and abundance of a full-size MPs from 1 µm to 5 mm. The present study quantified MPs with size ranges of 50 µm - 5 mm and 1-50 µm in the coastal marine waters from twelve locations in Hong Kong using fluorescence microscopy and flow cytometry respectively, during the end of wet (September 2021) and dry (March 2022) seasons. The average abundance of MPs with size ranges of 50 µm - 5 mm and 1-50 µm from twelve sampling locations marine surface waters were found ranging from 27 to 104 particles L-1 and 43,675-387,901 particles L-1 in the wet season respectively, and 13-36 particles L-1 and 23,178-338,604 particles L-1 in the dry season respectively. Significant temporal and spatial variations of small MPs abundance might be observed at the sampling locations, which were contributed by the influences of the estuary of Pearl River, sewage discharge points, land structure, and other anthropogenic activities. Based on the MPs abundance information, ecological risk assessment was conducted and revealed that the small MPs (< 10 µm) in coastal marine surface waters may pose potential health risks to aquatic organisms. Additional risk assessments are needed in order to determine whether or not the MPs exposure would cause health risks to the public.

Quantitative Assessment of Full Size Microplastics in Bottled and Tap Water Samples in Hong Kong.

Human exposure to microplastics (MPs) through drinking water has drawn serious concern recently because of the potential adverse health effects. Although there are reports on the occurrence of MPs in bottled water, little is known about the abundance of a whole spectrum of MPs with sizes ranging from 1 µm to 5 mm due to the restrictions of conventional MPs detection methods. Some studies using micro-Raman spectroscopy can achieve MPs with a size of <10 µm, however, quantitation of all MPs was extremely time consuming and only a small portion (<10%) of MPs would be analyzed. The present study quantified MPs from nine brands of bottled water using fluorescence microscopy and flow cytometry for MPs with a size of ≥50 µm and a size of <50 µm, respectively. The average abundance of MPs with a size of ≥50 µm in bottled water samples was found ranging from 8-50 particles L-1, while MPs with a size of <50 µm were found to be 1570-17,817 particles L-1, where the MPs abundance from mineral water samples were significantly more than distilled and spring water samples. The modal size and shape of MPs were found at 1 µm and fragments, respectively. Besides, three tap water samples obtained locally were analyzed and compared with the bottled water samples, where less MPs were found in tap water samples. In addition, contamination of MPs from bottle and cap and interference by addition of mineral salts were studied, where no significant difference from all these processes to the control sample was found, suggesting the major contamination of MPs was from other manufacturing processes. Estimated daily intake (EDI) of MPs increased substantially when data of small MPs are included, suggesting that previously reports on exposure of MPs from drinking water might be underestimated, as only large MPs were considered.

Astaxanthin Influence on Health Outcomes of Adults at Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis.

The use of medication is effective in managing metabolic syndrome (MetS), but side effects have led to increased attention on using nutraceuticals and supplements. Astaxanthin shows positive effects in reducing the risk of MetS, but results from individual studies are inconclusive. This systematic review summarizes the latest evidence of astaxanthin in adults with risk factors of MetS. A systematic search of English and Chinese randomized controlled trials in 14 electronic databases from inception to 30 June 2021 was performed. Two reviewers independently screened the titles and abstracts, and conducted full-text review, quality appraisal, and extraction of data. Risk of bias was assessed by PEDro. A total of 7 studies met the inclusion criteria with 321 participants. Six studies were rated to have excellent methodological quality, while the remaining one was rated at good. Results show marginal effects of astaxanthin on reduction in total cholesterol and systolic blood pressure, and a significant attenuating effect on low-density lipoprotein cholesterol. Further robust evidence is needed to examine the effects of astaxanthin in adults at risk of MetS.

Macroalgal morphology mediates microplastic accumulation on thallus and in sediments.

The accumulation process of microplastics (MPs) is a key to understanding their fate in the environment. However, there is limited information about the short-term accumulation of MPs on macrophytes. The ability of macrophyte to attenuate wave and reduce current velocity is potentially facilitating MPs deposition. We hypothesize that the macroalgae retain MPs with their morphologies (filamentous and non-filamentous) being one of the factors to govern retention. Our hypothesis was tested by field observation during the dry season in Hong Kong when the macroalgae communities were the most diverse. MPs per biomass, surface area, or interstitial volume were used to represent the abundances on macroalgae. We found that filamentous algae retained a 2.35 times higher number of MPs when compared with non-filamentous algae if unit per biomass was considered. Other units, however, showed insignificant differences in MPs abundances between algal morphologies. Fibre was the most dominant shape of MPs with no significant difference in their abundances between filamentous and non-filamentous algae, suggesting fibres were retained regardless of the algal morphologies. To further evaluate the potential accumulation in the environment, sediment samples were also collected under the algal mat and immediate vicinity (~50 cm) of the algal mat. We found that sediment collected under the vegetated area contained significantly higher MPs. This was 3.39 times higher than the unvegetated area. Sediment collected under/near filamentous algae retained much higher abundances of MPs than those of non-filamentous algae. Provided that the observed retention of MPs on macroalgae, we speculate macrophyte system is one of the short-term MPs accumulation hotspots where the temporal increase of MPs depends on the seasonality of macrophyte in a given region.

Removal and biodegradation of polycyclic aromatic hydrocarbons by Selenastrum capricornutum.

The removal and degradation of a mixture of polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene (PHE), fluoranthene (FLA), and pyrene (PYR), by a green microalgal species, Selenastrum capricornutum, at different initial cell densities were studied. The PAH removal efficiency increased with the initial cell density, and 96% of PHE, 100% of FLA, and 100% of PYR in the medium were removed by live S. capricornutum at the density of 1 x 10(7) cells/ml in 4 d, whereas less than 50% of PAHs were removed at the lowest cell density (5 x 10(4) cells/ml) in 7 d. The removal mechanisms included initial adsorption onto the cell walls of both live and dead cells, and the adsorbed PAHs were then absorbed and degraded in live cells only. Among different PAHs in a mixture, irrespective of whether they were added to medium at the same or different concentrations, the removal preference by live S. capricornutum was in the descending order of PYR > FLA > PHE, whereas the biodegradation rates followed the descending order of FLA > PYR > PHE. Initial findings regarding PAH metabolites revealed that PHE was converted into four different monohydroxyphenanthrenes and two dihydroxyphenanthrenes, whereas FLA and PYR were converted into three hydroxylated derivatives through the monooxygenase pathway. The presence of dihydroxylated PAHs suggested that the dioxygenase pathway also might have taken place at the same time.