Ultra-low concentration of chlorine dioxide regulates stress-caused premature leaf senescence in tobacco by modulating auxin, ethylene, and chlorophyll biosynthesis.

Exploring novel growth regulators for premature senescence regulation is important for tobacco production. In the present study, chlorine dioxide (ClO2) was explored as a novel plant growth regulator for tobacco growth, particularly its effect on leaf senescence and root development. The results showed that 0.15 µM ClO2 maintained the lushness of detached leaves and whole plants. Also, the leaves of ClO2-treated plants exhibited a chlorophyll content of 58% higher than in CK (control) plants (P < 0.05). Besides, ClO2 treatment increased the biomass of roots and aboveground parts by 54 and 16%, respectively. The ClO2-treated plants also showed enhanced activities of antioxidant enzymes and significantly reduced malondialdehyde contents (P < 0.05). Moreover, ClO2 treatment remarkably alleviated drought-caused premature senescence in the tobacco plants and partly rescued the exogenous ethylene-caused plant dwarfism. The indole-3-acetic acid content in ClO2-treated plants was higher than in non-treated plants (P < 0.05), but ethylene content was significantly lower (P < 0.05). Gene expression analysis showed that ClO2 treatment remarkably suppressed ethylene synthase genes. However, the auxin biosynthesis and transport genes were up-regulated, with NtIAA17 increasing by five folds (P < 0.05). Further, ClO2 remarkably up-regulated the expression of chlorophyll biosynthesis genes, with a >20-fold increase in NtHEMA1 and NtCHLH expressions. These results designate ClO2 as a potential regulator for improving tobacco productivity by retaining higher chlorophyll content and promoting root growth.

The Role of Standardized Phase Angle in the Assessment of Nutritional Status and Clinical Outcomes in Cancer Patients: A Systematic Review of the Literature.

Compared with the phase angle (PA), the predictive ability of the standardized phase angle (SPA) in assessing nutritional status and clinical outcomes in cancer patients remains uncertain. This review aimed to assess (1) the relationship between SPA and nutritional status and clinical outcomes (including complications and survival) in cancer patients; (2) the predictive ability of SPA alone and in comparison with the predictive ability of PA; and (3) the cut-off value of SPA in cancer patients. Studies that addressed the relationship of SPA use to nutritional status, complications, and survival in cancer patients were searched and identified from six electronic databases (PubMed, Medline, CINAHL, Embase, Web of Science, and the Cochrane Library). The included studies were considered to meet the following criteria: English studies with original data that reflected the effects of SPA on nutritional status and clinical outcomes (including complications and survival) and reported a cut-off value of SPA in cancer patients aged ≥18. Thirteen studies that included a total of 2787 participants were evaluated. Five studies assessed the relationship between SPA and nutritional status, and four of them reported a positive relationship between SPA and nutritional status in cancer patients, even considering SPA as a predictor. Twelve studies assessed the relationship between SPA and clinical outcomes in cancer patients. Two-thirds of the studies that evaluated complications reported the predictive ability of SPA; 30% of survival studies reported a positive relationship, 40% reported SPA as a predictor, and 30% reported no relationship. The standard cut-off value for SPA has not yet been determined. Data from the selected studies suggest that SPA might be a predictor of nutritional status. Further studies are needed to determine the value of SPA in predicting nutritional status and clinical outcomes in cancer patients.

Chemical characteristics, oxidative potential, and sources of PM2.5 in wintertime in Lahore and Peshawar, Pakistan.

The chemical characteristics, oxidative potential, and sources of PM2.5 were analyzed at the urban sites of Lahore and Peshawar, Pakistan in February 2019. Carbonaceous species, water soluble ions, and metal elements were measured to investigate the chemical composition and sources of PM2.5. The dithiothreitol (DTT) consumption rate was measured to evaluate the oxidative potential of PM2.5. Both cities showed a high exposure risk of PM2.5 regarding its oxidative potential (DTTv). Carbonaceous and some of the elemental species of PM2.5 correlated well with DTTv in both Lahore and Peshawar. Besides, the DTTv of PM2.5 in Lahore showed significant positive correlation with most of the measured water soluble ions, however, ions were DTT-inactive in Peshawar. Due to the higher proportions of carbonaceous species and metal elements, Peshawar showed higher mass-normalized DTT activity of PM2.5 compared to Lahore although the average PM2.5 concentration in Peshawar was lower. The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities. Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM2.5 and its oxidative potential. Mixed sources of traffic and road dust resuspension and coal combustion, direct vehicle emission, and biomass burning and formation of secondary aerosol were identified as the major sources of PM2.5 in both cities. The findings of this study provide important data for evaluation of the potential health risks of PM2.5 and for formulation of efficient control strategies in major cities of Pakistan.

Variation, sources and historical trend of black carbon in Beijing, China based on ground observation and MERRA-2 reanalysis data.

Based on the ground-measurements and MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis data, the temporal-spatial variation of black carbon (BC) in Beijing and the affecting factors were investigated. According to the ground-measured BC concentration in November months of 2014, 2015 and 2016, the before-heating period in November 2014 showed the lowest BC concentration as a result of the efficient emission controls for the Asia-Pacific Economic Cooperation (APEC) meeting. Except for November 2014, the BC mass concentration during the heating periods was notably lower than the before-heating periods in November 2015 and 2016. Wind speed and relative humidity appeared to be two important meteorological parameters affecting BC pollution. The MERRA-2 BC concentration was validated through comparison with the continuous ground BC measurements in 2015 and 2016, affirming its reliability in demonstrating the large scale and long term variations of the ground BC concentration. The MERRA-2 BC spatial distribution, the potential source regions determined by concentration weighted trajectory (CWT) analysis, and the regional emission inventories were combined to reveal the potential source regions and source types of BC in Beijing. Transportation emission in Beijing and residential emissions in the neighboring regions such as Hebei appeared to be important sources of BC in Beijing. According to the historical trends of MERRA-2 BC concentration and typical fossil fuel consumption (1980-2017), local coal and coke are no longer the major factor affecting the BC concentration, instead, liquid fuels such as gasoline, kerosene, and diesel may highly contribute to the BC pollution in Beijing in recent years. Regional transport of BC may have also contributed to the loading of BC in Beijing. Open biomass burning may be a non-negligible factor for the short-term variation of BC in the atmosphere.