Iodine-Mediated Alkoxyselenylation of Alkenes and Dienes with Elemental Selenium.

A one-pot synthesis of linear and cyclic ß-alkoxyselenides is developed through the iodine-mediated three-component reaction of elemental selenium with alkenes (dienes) and alcohols. Selenylation of 1,5-hexadiene gives 2,5-di(methoxymethyl)tetrahydroselenophene and 2-methoxy-6-(methoxymethyl)tetrahydro-2H-selenopyran via the 5-exo-trig and 6-endo-trig cyclization. 1,7-Octadiene affords only linear 1:2 adduct with two terminal double bonds. 1,5-Cyclooctadiene results in one diastereomer of 2,6-dialkoxy-9-selenabicyclo [3.3.1]nonanes via 6-exo-trig cyclization. With 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane, the first ring-substituted representative of a very rare class of heterocycles, 1,4,2,6-oxaselenadisilinanes, was obtained at a high yield.

Disrupting Six/Eya Signalling as New Therapy for Lung Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common type of interstitial lung disease, with a median survival of 2-4 years from the time of diagnosis [1]. It is estimated that the prevalence of IPF in the US is approximately 10-60 cases per 100,000 people, with limited pharmacological therapies available [2, 3]. IPF is a chronic, progressive disease characterized by alveolar injury, increased extracellular matrix (ECM) deposition and resultant alveolar destruction. Macroscopically, this leads to poor lung compliance, impaired trans-alveolocapillary membrane gas exchange and ultimately, end-stage respiratory failure, necessitating lung transplantation [2, 4, 5]. Several non-genetic risk factors, such as male sex, older age, and smoking, increase the risk of developing IPF [4, 6]. More recently, several genetic risk factors for IPF have also been discovered, including a single-nucleotide polymorphism (rs35705950) in the promoter region of MUC5B [7-9], which codes for an essential protein for airway clearance and innate immune response, along with genes associated with telomere maintenance, such as telomerase RNA component (TERC) and telomerase reverse transcriptase (TERT) [1, 10].

Insights into the significant increase in ozone during COVID-19 in a typical urban city of China

The outbreak of COVID-19 promoted strict restrictions to human activities in China, which led to a dramatic decrease in most air pollutant concentrations (e.g., PM2.5, PM10, NOx, SO2 and CO). However, an obvious increase in ozone (O3) concentrations was found during the lockdown period in most urban areas of China. In this study, we conducted field measurements targeting ozone and its key precursors by utilizing a novel proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) in Changzhou, which is representative of the Yangtze River Delta (YRD) city cluster of China. We further applied the integrated methodology including machine learning, an observation-based model (OBM) and sensitivity analysis to obtain insights into the reasons causing the obvious increase in ozone. Major findings include the following: (1) by deweathered calculation, we found changes in precursor emissions contributed 1.46 ppbv to the increase in the observed O3 during the full-lockdown period in 2020, while meteorology constrained 3.0 ppbv of O3 in the full-lockdown period of 2019. (2) By using an OBM, we found that although a significant reduction in O3 precursors was observed during the full-lockdown period, the photochemical formation of O3 was stronger than that during the pre-lockdown period. (3) The NOx/VOC ratio dropped dramatically from 1.84 during the pre-lockdown to 0.79 in the full-lockdown period, which switched O3 formation from a VOC-limited regime to the boundary of a NOx- and VOC-limited regime. Additionally, box model results suggested that the decrease in the NOx/VOC ratio during the full-lockdown period could increase the mean O3 by 2.4 ppbv. Results of this study give insights into the relationship between O3 and its precursors in urban area and demonstrate reasons for the obvious increase in O3 in most urban areas of China during the COVID-19 lockdown period. This study also underlines the necessity of controlling anthropogenic oxygenated volatile organic compounds (OVOCs), alkenes and aromatics in the sustained campaign of reducing O3 pollution in China.

Chemical Recycling of Plastic Marine Litter: First Analytical Characterization of The Pyrolysis Oil and of Its Fractions and Comparison with a Commercial Marine Gasoil

A detailed molecular fingerprint of raw pyrolysis oil from plastic wastes is a new research area. The present study focuses for the first time on the chemical recycling of plastic marine litter;we aim to chemically characterize the obtained raw pyrolysis oil and its distillates (virgin naphtha and marine gasoil) via GC-MS and FT-IR. For all samples, more than 30% of the detected compounds were identified. 2,4-dimethyl-1-heptene, a marker of PP pyrolysis, is the most represented peak in the chemical signature of all the marine litter pyrolysis samples, and it differentiates commercial and pyrolysis marine gasoil. The presence of naphthalenes is stronger in commercial gasoil, compared to its pyrolysis analog, while the opposite holds for olefins. The overlap between the two molecular fingerprints is impressive, even if saturated hydrocarbons are more common in commercial gasoil, and unsaturated compounds are more common in the gasoil derived from pyrolysis. A technical comparison between the commercial marine gasoil and the one obtained from the marine litter pyrolysis is also attempted. Gasoil derived from marine litter fully complies with the ISO8217 standards for distillate marine fuel. On the other hand, the virgin naphtha is particularly rich in BTX, ethylbenzene, styrene, and alpha olefins, which are all important recoverable platform chemicals for industrial upcycling.