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The study aims to determine the concentration, size distribution and analyze the relationship of indoor and outdoor particles in urban area, in Vietnam. One thousand two hundred daily samples of PM 0.1 , PM 0.1-0.5 , PM 0.5-1 , PM 1-2.5 , PM 2.5-10 , PM >10 were taken simultaneously at four residential houses in summer and winter by nano sampler (Model 3182, Kinomax). The average concentrations of indoor PM 0.1 , PM 0.5 , PM 1 , PM 2.5 and PM 10 were in range of 5.3-8.9 μg/m 3 ; 10.8-20.1μg/m 3 ; 20.5-47.6 μg/m 3 ; 33.7-105.9 μg/m 3 and 44.7-135.0 μg/m 3 among four houses, respectively. The concentrations of outdoor PM 2.5 , PM 10 were considerately higher than those of indoor PM, whereas negligible differences on concentrations of PM 0.1 , PM 0.5 and PM 1 were observed. The significantly seasonal variation was observed for indoor PM 1 , PM 2.5 and PM 10 , but not for PM 0.1 and PM 0.5 . Majority of indoor fractions were origin from outdoor sources. Unimodal distributions of indoor particles determined the super-micron size (1 to 2.5 μm) with highest concentration and PM <0.5 and PM >10 with lowest concentration. Fine particles with interval sizes (PM 0.5-1 and PM 1-2.5 ) contributed to the predominance to coarse particles in both indoors and outdoors, suggesting serious threat on human health.

Every year, Hanoi suffers from several episodes (periods with daily concentration of PM 2.5 higher than 50 µg m −3 during at least two consecutive days). These episodes are of health concern because of the high concentration of PM 2.5 and/or PM 0.1 and the presence of PM-bound toxic components, such as, PAHs. In this study, the concentrations of PAHs bound to PM 2.5 and PM 0.1 in night-time and day-time samples during episode and non-episode periods in December 2021 were determined. The concentrations of PAHs bound to PM 2.5 were found to increase significantly from day-time samples of 3.24 ± 0.83 ng m −3 to night-time samples of 10.8 ± 4.45 ng m −3 in episode periods. However, PAHs bound to PM 0.1 increased slightly from day-time samples of 0.58 ± 0.12 ng m −3 to night-time samples of 0.89 ± 0.30 ng m −3 in episode periods. Diagnostic ratios of PAHs indicate that biomass/coal combustion and vehicular emission are the primary sources of PAHs. The incremental lifetime cancer risk was estimated to vary from 8.7E-09 to 2.5E-08 for children and 6.7E-08 to 2.2E-07 for adults, respectively. Accordingly, loss of life expectancy was estimated at 0.11 min and 0.82 min for children and adults, respectively. These findings imply that the carcinogenic impact induced by PAHs via inhalation is negligible during the episode period.

Haze is a well-known air pollution phenomenon linked to the severe and persistent particulate matter (PM) episodes in Southeast Asia (SEA), which significantly impacts the environment, health, and economy. This work reviewed for the first time the characteristics of haze episodes in terms of PM concentrations, chemical compositions, and the causes of haze in both Lower (Maritime) and Upper (Mainland) SEA. In addition, we carried out a systematic comparison of the frequency and intensity of haze events through SEA regions in recent years. Our finding indicated that the different trend of haze frequency and intensity between SEA cities are not only due to local air pollution sources such as biomass burning (BB) but also meteorology and long-range transport. Other sources such as secondary aerosols also play an important role in haze formation, but they have not been comprehensively investigated in previous studies. Due to the complicated formation mechanisms and the transportations of haze and its impacts on SEA’s human health and economy, more sophisticated and specific policies are needed to deal with haze issues not only for individual countries but also on a regional scale.

Every year, Hanoi suffers from several episodes (periods with daily concentration of PM higher than 50 µg m during at least two consecutive days). These episodes are of health concern because of the high concentration of PM and/or PM and the presence of PM-bound toxic components, such as, PAHs. In this study, the concentrations of PAHs bound to PM and PM in night-time and day-time samples during episode and non-episode periods in December 2021 were determined. The concentrations of PAHs bound to PM were found to increase significantly from day-time samples of 3.24 ± 0.83 ng m to night-time samples of 10.8 ± 4.45 ng m in episode periods. However, PAHs bound to PM increased slightly from day-time samples of 0.58 ± 0.12 ng m to night-time samples of 0.89 ± 0.30 ng m in episode periods. Diagnostic ratios of PAHs indicate that biomass/coal combustion and vehicular emission are the primary sources of PAHs. The incremental lifetime cancer risk was estimated to vary from 8.7E-09 to 2.5E-08 for children and 6.7E-08 to 2.2E-07 for adults, respectively. Accordingly, loss of life expectancy was estimated at 0.11 min and 0.82 min for children and adults, respectively. These findings imply that the carcinogenic impact induced by PAHs via inhalation is negligible during the episode period.

Since it was first discovered, thousands of years ago, silkworm silk has been known to be an abundant biopolymer with a vast range of attractive properties. The utilization of silk fibroin (SF), the main protein of silkworm silk, has not been limited to the textile industry but has been further extended to various high-tech application areas, including biomaterials for drug delivery systems and tissue engineering. The outstanding mechanical properties of SF, including its facile processability, superior biocompatibility, controllable biodegradation, and versatile functionalization have allowed its use for innovative applications. In this review, we describe the structure, composition, general properties, and structure-properties relationship of SF. In addition, the methods used for the fabrication and modification of various materials are briefly addressed. Lastly, recent applications of SF-based materials for small molecule drug delivery, biological drug delivery, gene therapy, wound healing, and bone regeneration are reviewed and our perspectives on future development of these favorable materials are also shared.

Titanium dioxide (TiO2) has attracted increasing attention as a candidate for the photocatalytic reduction of carbon dioxide (CO2) to convert anthropogenic CO2 gas into fuels combined with storage of intermittent and renewable solar energy in forms of chemical bonds for closing the carbon cycle. However, pristine TiO2 possesses a large band gap (3.2 eV), fast recombination of electrons and holes, and low selectivity for the photoreduction of CO2. Recently, considerable progress has been made in the improvement of the performance of TiO2 photocatalysts for CO2 reduction. In this review, we first discuss the fundamentals of and challenges in CO2 photoreduction on TiO2-based catalysts. Next, the recently emerging progress and advances in TiO2 nanostructured and hybrid materials for overcoming the mentioned obstacles to achieve high light-harvesting capability, improved adsorption and activation of CO2, excellent photocatalytic activity, the ability to impede the recombination of electrons-holes pairs, and efficient suppression of hydrogen evolution are discussed. In addition, approaches and strategies for improvements in TiO2-based photocatalysts and their working mechanisms are thoroughly summarized and analyzed. Lastly, the current challenges and prospects of CO2 photocatalytic reactions on TiO2-based catalysts are also presented.

Image-based ship detection is a critical function in maritime security. However, lacking high-quality training datasets makes it challenging to train a robust supervision deep learning model. Conventional methods use data augmentation to increase training samples. This approach is not robust because the data augmentation may not present a complex background or occlusion well. This paper proposes to use an information bottleneck and a reparameterization trick to address the challenge. The information bottleneck learns features that focus only on the object and eliminate all backgrounds. It helps to avoid background variance. In addition, the reparameterization introduces uncertainty during the training phase. It helps to learn more robust detectors. Comprehensive experiments show that the proposed method outperforms conventional methods on Seaship datasets, especially when the number of training samples is small. In addition, this paper discusses how to integrate the information bottleneck and the reparameterization into well-known object detection frameworks efficiently.

Black pepper (Piper nigrum L.) is a tropical crop with extensive medicinal potential in ethnomedicine and nutraceutical applications. The essential oil of black pepper finds wide applications in inhabitation of respiratory infections and soothing of muscular pains due to its warming and energizing property. The pungent bioactive piperine is responsible for this function, and therefore, efficient technology is required for an optimal extraction process of this compound. In the present article, we have developed a procedure for extracting black pepper essential oil from Vietnam, optimizing conditions that affect the extraction process. The effect of process parameters, namely material size, preservation method, the concentration of sodium chloride, the concentration of soak time, the ratio of material to water, temperature extraction, time extraction on the extraction yield, and relative efficiency were investigated. Results demonstrated that 20 g of black pepper milled with a mesh size of 160 obtained 0.48 g of essential oil (2.4%) at a raw material to water ratio of 1/21 (g/mL) at 150 °C in a time of 5.2 h. GC-MS (Gas chromatography–mass spectrometry) spectra showed that 3-carene (29.21%), D-limonene (20.94%), caryophyllene (15.05%), and β-pinene (9.77%) were present as major components. These results suggested that the essential oil extracted from Vietnamese black pepper is applicable in the manufacturing processes of insecticides and air deodorizers.

There is an increasing research interest in indoor air quality at schools as children who are among the most sensitive to air pollution spend a lot of time indoors. This study aims to estimate BTEX levels, sources, and assess their health risk at ten preschools in Hanoi, Vietnam. Two sampling campaigns were conducted in November and December, 2017, and May and June, 2018, with a total of 80 samples collected. BTEX were sampled by mini air samplers, and the analysis was performed by using GC/MS. During class, indoor concentrations of benzene, toluene, ethylbenzene, and xylene were within the range of 1.22–6.01, 1.6–63.4, 0.94–6.34, and 0.86–3.52 μg m−3, while corresponding values obtained in the absence of children were 1.62–6.90, 1.20–125.3, 0.58–25.1, and 0.60–6.65 μg m−3, respectively. Indoor/outdoor ratios of BTEX varied from school to school, and ranged from 0.4 to 14.2, implying the presence of indoor emission sources. Insignificant indoor sources of benzene were found in all examined schools, whereas there were sources of toluene, ethylbenzene, and xylenes, probably associated with paint’s solvents, glues, and cleaning agents. Outdoor BTEX originated from the common sources, being mainly composed of automobile traffic. There was insignificant cancer and non-carcinogenic risk to children at the monitored preschools, with LCR values within the range of 0.059–6.6 × 10−5, and HQ values below 0.31. Monte Carlo simulation revealed that indoor and outdoor concentrations of BTEX influenced the most the results on lifetime cancer risk for indoors and outdoors, with a typical contribution of more than 90% to LCR variance.