Systematic monitoring of air quality are lacking in many parts of the world, especially in cities where air quality is poor. Since 2008, the U.S. Embassy in Beijing has been collecting real-time ...air-quality data from a monitor on the Embassy's rooftop and sharing that data publicly through social media. Using this freely available data, as well as those from four other U.S. consulates in China that are also now collecting and sharing data publicly, we demonstrate that rooftop air-quality monitors installed at embassies and consulates can further our understanding of air quality and provide a rich, hourly-averaged, long-term data source for the academic community and decision-makers. For example, this is the first study to present an analysis of diurnal variability of PM2.5 in Chengdu, Guangzhou, Shanghai, and Shenyang. We analyzed the diurnal variability of PM2.5 over the entire period of measurement for those cities and Beijing, and found marked variation across seasons and between cities. This dataset allows comparison of the PM2.5 annual average concentrations in 2013, with Guangzhou reporting 56.3 μg/m3, Shanghai 61.6 μg/m3, Chengdu 96.1 μg/m3, Beijing 99.6 μg/m3, and Shenyang 76.3 μg/m3 (note the average in Shenyang is from August 2013–July 2014). This study demonstrates the potential uses of air quality data that is currently systematically being collected and made publicly accessible by U.S. embassies and consulates in polluted but under-studied locations.
•Demonstrates utility of continuous, public air quality data from U.S. diplomatic facilities.•First analysis of diurnal PM2.5 variability of large polluted Chinese cities.•Found marked diurnal PM2.5 variability across seasons and between cities.•Beijing had the highest annual average but all cities had episodic poor air quality.
Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, ...methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.
Based on the activity of 23 TSCs on CZ taken from the literature, we have developed a QSAR model for predicting the activity of TSCs. New TSCs were designed and then tested against CZP, resulting in ...inhibitors with IC50 values in the nanomolar range. The modelling of the corresponding TSC-CZ complexes by molecular docking and QM/QM ONIOM refinement indicates a binding mode compatible with what was expected for active TSCs, according to a geometry-based theoretical model previously developed by our research group. Kinetic experiments on CZP suggest that the new TSCs act by a mechanism that involves the formation of a reversible covalent adduct with slow association and dissociation kinetics. These results demonstrate the strong inhibitory effect of the new TSCs and the benefit of the combined use of QSAR and molecular modelling techniques in the design of new and potent CZ/CZP inhibitors.
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•A QSAR model for a series of thiosemicarbazones was proposed from IC50 values on cruzain and physicochemical descriptors.•Taking into account the model, some new thiosemicarbazones were designed, synthesized and evaluated against cruzipain.•The designed compounds were active in nanomolar order, resulting in a very promissory candidates for future studies.•The activity of the new derivatives was rationalizated by theoretical methods: molecular docking followed by QM-QM ONIOM.
Aurein 1.2 is an antimicrobial peptide (AMP) with known lytic activity against bacterial membranes. Our previous studies revealed a differential action of aurein by both experimental and ...computational methods. This differential action was over membranes of two related probiotic strains, where the main difference between membranes was the number of glycolipids in the lipid composition. In this work, we aimed to investigate the interaction of aurein 1.2 with model bacterial membranes of varying glycolipid content. To this end, we performed extensive molecular dynamics simulations using the MARTINI coarse-grain force field and differential mixtures of phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and monogalactosylglycerol (MG). We found a correlation between the presence of MG in PG/PE mixtures and the difficulty of aurein to stabilize pore structures, suggesting an AMP-resistance factor encoded in the lipid composition of the membrane. These findings may shed light on a possible mechanism of bacterial resistance to AMPs that is related to the glycolipid content of bacterial membranes.
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