Qualitative and quantitative rapid detection of VOCs differentially released by VAP-associated bacteria using PTR-MS and FGC-PTR-MS.

Ventilator-associated pneumonia (VAP) is a prevalent disease caused by microbial infection, resulting in significant morbidity and mortality within the intensive care unit (ICU). The rapid and accurate identification of pathogenic bacteria causing VAP can assist clinicians in formulating timely treatment plans. In this study, we attempted to differentiate bacterial species in VAP by utilizing the volatile organic compounds (VOCs) released by pathogens. We cultured 6 common bacteria in VAP in vitro, including Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Staphylococcus aureus, which covered most cases of VAP infection in clinic. After the VOCs released by bacteria were collected in sampling bags, they were quantitatively detected by a proton transfer reaction-mass spectrometry (PTR-MS), and the characteristic ions were qualitatively analyzed through a fast gas chromatography-proton transfer reaction-mass spectrometry (FGC-PTR-MS). After conducting principal component analysis (PCA) and analysis of similarities (ANOSIM), we discovered that the VOCs released by 6 bacteria exhibited differentiation following 3 h of quantitative cultivation in vitro. Additionally, we further investigated the variations in the types and concentrations of bacterial VOCs. The results showed that by utilizing the differences in types of VOCs, 6 bacteria could be classified into 5 sets, except for A. baumannii and E. cloacae which were indistinguishable. Furthermore, we observed significant variations in the concentration ratio of acetaldehyde and methyl mercaptan released by A. baumannii and E. cloacae. In conclusion, the VOCs released by bacteria could effectively differentiate the 6 pathogens commonly associated with VAP, which was expected to assist doctors in formulating treatment plans in time and improve the survival rate of patients.

Rapid and non-invasive diagnosis of type 2 diabetes through sniffing urinary acetone by a proton transfer reaction mass spectrometry.

Urinary acetone in urine is produced from fat metabolism in human body, which can be accelerated in diabetic patients because of insufficient utilization and storage of glucose. In this study, we tried to develop a novel diagnosis method of type 2 diabetes (T2D) through sniffing urinary acetone by a proton transfer reaction mass spectrometry (PTR-MS). A total of 180 T2D patients and 180 healthy volunteers were recruited from three hospitals for multicenter study. Urine samples were collected in the morning when donators were fasting and stored in glass bottles. Acetone in the headspace of these bottles was qualitatively and quantitatively detected by the PTR-MS in 8 h. Using a threshold of 690.1 ppbv, a diagnostic model was established using urinary acetone with an accuracy of 81.3% (sensitivity: 73.3%, specificity: 89.3%) in hospital Ⅰ. In the verification studies, the accuracies were 92.5% (sensitivity: 88.7%, specificity: 96.2%) in hospital Ⅱ and 83.7% (sensitivity: 76.9%, specificity: 90.4%) in hospital Ⅲ, respectively. The accuracy is comparable to that of clinically used diagnosis methods, fasting plasma glucose (FPG), oral glucose tolerance test (OGTT), and glycosylated hemoglobin A1c (HbA1c) test. The sensitivity for 35 newly diagnosed patients was 85.7%. The newly developed technology is completely non-invasive and much more rapid than clinical FPG, OGTT, and HbA1c tests. It has a promising prospect in clinical use. But the applicability in different human races still need more validations.

Analysis of volatile organic compounds from deep airway in the lung through intubation sampling.

Exhaled volatile organic compounds (VOCs) have been widely applied for the study of disease biomarkers. Oral exhalation and nasal exhalation are two of the most common sampling methods. However, VOCs released from food residues and bacteria in the mouth or upper respiratory tract were also sampled and usually mistaken as that produced from body metabolism. In this study, exhalation from deep airway was first directly collected through intubation sampling and analyzed. The exhalation samples of 35 subjects were collected through a catheter, which was inserted into the trachea or bronchus through the mouth and upper respiratory tract. Then, the VOCs in these samples were detected by proton transfer reaction mass spectrometry (PTR-MS). In addition, fast gas chromatography proton transfer reaction mass spectrometry (FGC-PTR-MS) was used to further determine the VOCs with the same mass-to-charge ratios. The results showed that there was methanol, acetonitrile, ethanol, methyl mercaptan, acetone, isoprene, and phenol in the deep airway. Compared with that in oral exhalation, ethanol, methyl mercaptan, and phenol had lower concentrations. In detail, the median concentrations of ethanol, methyl mercaptan, and phenol were 7.3, 0.6, and 23.9 ppbv, while those in the oral exhalation were 80.0, 5.1, and 71.3 ppbv, respectively, which meant the three VOCs mainly originated from the food residues and bacteria in the mouth or upper respiratory tract, rather than body metabolism. The research results in our study can provide references for expiratory VOC research based on oral and nasal exhalation samplings, which are more feasible in clinical practice.

Is Emissions Trading Scheme (ETS) an Effective Market-Incentivized Environmental Regulation Policy? Evidence from China's Eight ETS Pilots.

Climate change and environmental issues caused by carbon emissions have attracted the attention of governments around the world. Drawing on the experience of the EU, China is actively developing a national carbon emissions trading market, trying to encourage emission entities to incorporate carbon emissions reduction into production and consumption decisions through carbon pricing. Is this scheme an effective market-incentivized environmental regulatory policy? Since China successively launched ETS pilots in 2013, the effectiveness of reducing carbon emissions has become one of the current focus issues. This study uses the difference-in-differences (DID) method to evaluate the impact of ETS implementation on emissions reduction and employs the Super-SBM model in data envelopment analysis (DEA) to evaluate the emission-reduction efficiency of eight ETS pilots in China. We find that the carbon trading policy has achieved emission-reduction effects in the implementation stage, and the greenness of economic growth has a significant positive impact on regional GDP. The establishment of China's unified carbon market should be coordinated with regional development. Some supporting measures for regional ecological compensation and the mitigation of regional development are yet to be adopted.

Exploring the effect of economic and environment factors on PM2.5 concentration: A case study of the Beijing-Tianjin-Hebei region.

Air pollution, especially haze pollution is a serious environment problem that directly affects the sustainable development in China. Identifying the key factors affecting PM2.5 concentration and the interaction mechanism between them through quantitative analysis can greatly help a city devise PM2.5 pollution control strategy. Using the geographical detector model, we quantitative measured 13 cities in the Beijing-Tianjin-Hebei region's social factors and their interaction impacts on PM2.5 concentration in 2016. In the analysis process, factor analysis method is used to separate the factors preliminary. According to the results, the factors mainly divided into two categories, i.e. economic factor and environment factor. R&D ranks top in the studied cities in terms of factor detection results, presenting closely relationship between PM2.5 concentration and R&D. We also find the interaction between any two factors all enhance impact on PM2.5 concentration than any one alone. This study provided a scientific basic and guidance for measure the driving degree of social factors and their interaction effects.

How does environmental regulation affect haze pollution governance?-An empirical test based on Chinese provincial panel data.

Recently, haze pollution is the most serious air problem in China. In the process of haze pollution governance, environmental regulation not only has a direct impact on haze pollution but may also affects haze pollution indirectly through four transmission channels, which are coal consumption, foreign direct investment (FDI), industrial structure and technological innovation. The purpose of this paper is to clarify how environmental regulation affects haze pollution governance through both direct and indirect impacts. Based on the difference Generalized Method of Moments (GMM), this paper explores the direct and indirect impact of environmental regulation on haze pollution governance over the period 2006-2016. The results show that China's current environmental regulation had effectively inhibited the haze pollution and achieved the expected effects. For coal consumption, it significantly aggravated haze pollution, but the ER implemented or not. However, environmental regulation provided a force mechanism to promote transformation and upgrading of industrial structure, thus to reverse the impact direction of industrial structure on haze pollution and mitigated the haze pollution. Moreover, the results indicate that FDI in China turned out to have a "pollution halo" effect and reduced the degree of haze pollution, while technological innovation had the "compliance cost" effect and increased the degree of haze pollution. Additionally, we find that automobile exhaust emissions and economic development were also important reasons for the increase of haze. According to the results, some policy implications were provided for the future haze pollution governance.

In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium-calcium silicate and calcium sulfate for bone regeneration.

Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium-calcium silicate (m-MCS) with specific surface area (410.9 m² g(-1)) and pore volume (0.8 cm³ g(-1)) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris-HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration.