[Pollution Characteristics，Source Analysis，and Activity Analysis of Atmospheric VOCs During Winter and Summer Pollution in Zhengzhou].

In order to study the pollution characteristics of volatile organic compounds （VOCs）， continuous monitoring of VOCs in two pollution processes was conducted in June and December 2021 in Zhengzhou. Combined with meteorological conditions， the pollution characteristics， source contributions， and reactivity of VOCs in winter and summer were compared and analyzed. The results showed that the volume fraction of atmospheric VOCs in two episodes were （27.92±12.68）×10-9 and （24.30±5.93）×10-9， respectively. The volume fraction of atmospheric VOCs in the haze pollution process in winter was larger than that in the ozone pollution process in summer. The analysis results of winter sources were as follows： industrial source （27.0%）， motor vehicle source （22.5%）， combustion source （20.1%）， solvent use source （16.3%）， and oil and gas volatilization source （14.1%）. The analysis results of summer sources were as follows： motor vehicle source （24.8%）， industrial source （24.1%）， solvent source （17.4%）， oil and gas volatilization source （14.2%）， combustion source （11.2%）， and plant source （8.4%）. The results of the smog production model showed that the proportion of days in the synergistic control zone of VOCs during the two pollution processes in summer （66.7%） was smaller than that in winter （100.0%）. The secondary reaction activity results showed that the average ·OH loss rate （L·OH） values in winter and summer were 4.12 s-1 and 4.75 s-1， respectively. The average ozone formation potential （OFP） values in summer were 108.36 µg·m-3. The olefins were dominant in the top ten species due to L·OH and OFP contributions in summer. The total SOAFP values in winter in Zhengzhou were 54.38 µg·m-3. Among the top ten species contributing to SOAFP in winter， nine were aromatic hydrocarbons.

Association of diabetes, education level, and care dependency with use of temporary vascular access in patients with chronic kidney disease.

OBJECTIVE: Temporary vascular access (TVA) is frequently used during the first dialysis in patients with chronic kidney disease (CKD), and it is associated with an increased risk of infection, central vein stenosis, and mortality. Here, factors associated with TVA in patients with CKD were explored. METHODS: This study included patients in a single-center CKD care program who initiated long-term renal replacement therapy. The primary outcome was TVA use at first dialysis. Factors possibly associated with TVA use were analyzed using Cox regression. RESULTS: Temporary vascular access was used in 53.2% of the patients at first dialysis. In total, 73.2% (n = 865) and 26.8% (n = 317) of the patients were on hemodialysis and peritoneal dialysis, respectively. Multivariate Cox regression analysis showed that TVA use in patients with CKD was associated with diabetes (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.28-1.81, p < 0.001), lower albumin (HR 0.82, 95% CI 0.75-0.91, p < 0.001), lower education level (HR 0.75, 95% CI 0.56-1.00, p = 0.055), and total care dependency (HR 1.92, CI 1.44-3.43, p = 0.003). CONCLUSION: Diabetes, education level, and care dependency are associated with TVA at dialysis initiation in patients with CKD.