Closed-loop recycling of sulfur-rich polymers with tunable properties spanning thermoplastics, elastomers, and vitrimers.

The development of closed-loop recycling polymers that exhibit excellent performance is of great significance. Sulfur-rich polymers possessing excellent optical, thermal, and mechanical properties are promising candidates for chemical recycling but lack efficient synthetic strategies for achieving diverse structures. Herein, we report a universal synthetic strategy for producing polytrithiocarbonates, a class of sulfur-rich polymers, via the polycondensation of dithiols and dimethyl trithiocarbonate. This strategy has excellent compatibility with a wide range of monomers, including aliphatic, heteroatomic, and aromatic dithiols enabling the synthesis of polytrithiocarbonates with diverse structures. The present synthesis strategy offers a versatile platform for the construction of thermoplastics, elastomers, and vitrimers. Notably, these polytrithiocarbonates can be easily depolymerized via solvolysis into the corresponding monomers, which can be repolymerized to virgin polymers without changing the material properties.

Association between diurnal temperature range and respiratory tract infections.

OBJECTIVE: This study aimed to assess the association between emergency-room visits for respiratory tract infection (RTI) with diurnal temperature range (DTR), a weather parameter closely associated with urbanization and global climate change. METHODS: We conducted a semiparametric time-series analysis to estimate the percentage increase in emergency-room visits for RTI associated with changes in DTR after adjustment for daily weather conditions (temperature and relative humidity) and outdoor air pollution. RESULTS: DTR was significantly associated with daily emergency-room visits for RTI. An increase of 1 °C in the current-day (L0) and in the 2-day moving average (L01) DTR corresponded to a 0.94% [95% confidence interval (CI), 0.34%-1.55%] and 2.08% (95% CI, 1.24%-2.93%) increase in emergency-room visits for RTI, respectively. CONCLUSION: DTR was associated with increased risk of RTI. More studies are needed to understand the impact of DTR on respiratory health.

[Effects of airborne fine particulate matter on human respiratory symptoms and pulmonary function].

OBJECTIVE: to explore effects of airborne fine particulate matter exposure on human respiratory symptoms and pulmonary function. METHODS: one hundred and seven field traffic policemen were recruited as airborne fine particulate matter high-exposure group and one hundred and one male residents as common exposure group. The individual sampler was used to measure fine particulate matter exposure levels of the two groups. To obtain personal information, especially respiratory symptoms such as cough, sputum, etc. a questionnaire survey was used. The pulmonary ventilation function was detected: forced expiratory vital capacity (FVC), the first 1 second forced expiratory volume (FEV1.0), FVC/FEV1.0% and peak flow values (PEF), and the difference of fine particulate matter exposure level and respiratory function of the two groups was compared. RESULTS: 24 h individual average fine particulate matter exposure concentration of traffic police and residents were respectively (115.4 ± 46.17) microg/m(3) and (74.94 ± 40.09) microg/m(3), the traffic police PM2.5 exposure levels were significantly higher than the residents. In the incidence of respiratory symptoms, compared with high-exposure group and common exposure group, coughing, expectoration, throat unwell, asthma, short of breath and nose discomfort, traffic police group was higher than residents group (P < 0.05). The abnormal rate of lung ventilation function indexes, such as FVC and FEV1.0 was 25.23% and 12.15% respectively in high-exposure group, 11.88% and 2.97% in common exposure group, there was no statistical difference between two groups. Besides, the abnormal rate of FVC and FEV1.0, showed rising trend in high-exposure group with seniority. CONCLUSION: long-term higher levels of airborne fine particulate matter exposure, may impact respiratory health and impair pulmonary function.