Spatiotemporal patterns of particulate matter (PM) and associations between PM and mortality in Shenzhen, China

DOI: 10.1186/s12889-016-2725-6Background: Most studies on air pollution exposure and its associations with human health in China have focused on the heavily polluted industrial areas and/or mega-cities, and studies on cities with comparatively low air pollutant concentrations are still rare. Only a few studies have attempted to analyse particulate matter (PM) for the vibrant economic centre Shenzhen in the Pearl River Delta. So far no systematic investigation of PM spatiotemporal patterns in Shenzhen has been undertaken and the understanding of pollution exposure in urban agglomerations with comparatively low pollution is still limited. Methods: We analyze daily and hourly particulate matter concentrations and all-cause mortality during 2013 in Shenzhen, China. Temporal patterns of PM (PM2.5 and PM10) with aerodynamic diameters of 2.5 (10) μm or less (or less (including particles with a diameter that equals to 2.5 (10) μm) are studied, along with the ratio of PM2.5 to PM10. Spatial distributions of PM10 and PM2.5 are addressed and associations of PM10 or PM2.5 and all-cause mortality are analyzed. Results: Annual average PM10 and PM2.5 concentrations were 61.3 and 39.6 μg/m3 in 2013. PM2.5 failed to meet the Class 2 annual limit of the National Ambient Air Quality Standard. PM2.5 was the primary air pollutant, with 8.8 % of days having heavy PM2.5 pollution. The daily PM2.5/PM10 ratios were high. Hourly PM2.5 concentrations in the tourist area were lower than downtown throughout the day. PM10 and PM2.5 concentrations were higher in western parts of Shenzhen than in eastern parts. Excess risks in the number of all-cause mortality with a 10 μg/m3 increase of PM were 0.61 % (95 % confidence interval [CI]: 0.50–0.72) for PM10, and 0.69 % (95 % CI: 0.55–0.83) for PM2.5, respectively. The greatest ERs of PM10 and PM2.5 were in 2-day cumulative measures for the all-cause mortality, 2-day lag for females and the young (0–65 years), and L02 for males and the elder (>65 years). PM2.5 had higher risks on all-cause mortality than PM10. Effects of high PM pollution on mortality were stronger in the elder and male. Conclusions: Our findings provide additional relevant information on air quality monitoring and associations of PM and human health, valuable data for further scientific research in Shenzhen and for the on-going discourse on improving environmental policie

Low-dose ATG combined with low-dose PTCY in preventing GVHD after haploidentical transplantation: a retrospective analysis of 90 cases

Objective To retrospectively analyze the efficacy and safety of low-dose antithymocyte globulin (ATG) combined with low-dose post transplantation cyclophosphamide (PTCY) in prevention of graft versus host disease (GVHD) after haploidentical transplantation. Methods Clinical data of 90 patients receiving haplotype matched transplantation in No.920 Hospital of PLA Joint Logistic Support Force from January 2022 to February 2023 were collected, and they were divided into study group (n=47) and control group (n=43) according to different GVHD prevention programs.The patients of the study group were given low-dose ATG combined with low-dose PTCY, and those of the control group received standard dose of PTCY.The implantation status, occurrence of GVHD, survival status and other indicators were analyzed between the 2 groups. Results ① Both groups of patients were successfully implanted, the median duration for neutrophil implantation (11 vs 17 d, P < 0.05) and platelet implantation (12 vs 20 d, P < 0.05) was significantly shorter in the study group than the control group.The incidence of grade Ⅱ~Ⅳ aGVHD (12.8%vs 34.9%, P < 0.05) and grade Ⅲ~Ⅳ aGVHD (6.4%vs 20.9%, P < 0.05) was significantly lower in the study group than the control group, so was the non-recurrent mortality rate (6.4%vs 20.9%, P < 0.05) and the incidence of hemorrhagic cystitis (12.8%vs 34.9%, P < 0.05).② By the end of the study, there were no significant differences in the incidence of mild and moderate and severe cGVHD, recurrence rate, reactivation rates of EBV and CMV, overall survival rate or progression-free survival rate between the 2 groups. Conclusion For haploidentical transplantation, low-dose ATG combined with low-dose PTCY has the advantages of lower incidence of GVHD, non-recurrent mortality, incidence of hemorrhagic cystitis and faster implantation

Male and Female Subpopulations of Salix viminalis Present High Genetic Diversity and High Long-term Migration Rates between Them

Dioecy distributed in 157 flowering plant families and 959 flowering plant genera. Morphological and physiological differences between male and female plants have been studied extensively, but studies of sex-specific genetic diversity are relatively scarce in dioecious plants. In this study, 20 SSR loci were employed to examine the genetic variance of male subpopulations and female subpopulations in Salix viminalis. The results showed that all of the markers were polymorphic (Na=14.15, He=0.7566) and workable to reveal the genetic diversity of S. viminalis. No statistically significant difference was detected between male and female subpopulations, but the average genetic diversity of male subpopulations (Na=7.12, He=0.7071) and female subpopulations (Na=7.31, He=0.7226) were high. Under unfavorable environments (West Liao basin), the genetic diversity between male and female subpopulations was still not significantly different, but the genetic diversity of sexual subpopulations were lower. The differentiation of the ten subpopulations in S. viminalis was moderate (FST=0.0858), which was conformed by AMOVA that most of genetic variance (94%) existed within subpopulations. Pairwise FST indicated no differentiation between sexual subpopulations, which was accompanied by high long-term migrate between them (M=0.73~1.26). However, little recent migration was found between sexual subpopulations. Therefore, artificial crossing or/and transplantation by cutting propagation should be carried out so as to increase the migration during the process of ex situ conservation

Unveiling the dynamic of nitrogen through migration and transformation patterns in the groundwater level fluctuation zone of a different hyporheic zone sediment

Abstract This study investigates the impact of water levels and soil texture on the migration and transformation of nitrate (NO3 −-N) and ammonium (NH4 +-N) within a soil column. The concentrations of NO3 −-N gradually decreased from an initial concentration of 34.19 ± 0.86 mg/L to 14.33 ± 0.77 mg/L on day 70, exhibiting fluctuations and migration influenced by water levels and soil texture. Higher water levels were associated with decreased NO3 −-N concentrations, while lower water levels resulted in increased concentrations. The retention and absorption capacity for NO3 −-N were highest in fine sand soil, followed by medium sand and coarse sand, highlighting the significance of soil texture in nitrate movement and retention. The analysis of variance (ANOVA) confirmed statistically significant variations in pH, dissolve oxygen and oxidation–reduction potential across the soil columns (p < 0.05). Fluctuating water levels influenced the migration and transformation of NO3 −-N, with distinct patterns observed in different soil textures. Water level fluctuations also impacted the migration and transformation of NH4 +-N, with higher water levels associated with increased concentrations and lower water levels resulting in decreased concentrations. Among the soil types considered, medium sand exhibited the highest absorption capacity for NH4 +-N. These findings underscore the significant roles of water levels, soil texture, and soil type in the migration, transformation, and absorption of nitrogen compounds within soil columns. The results contribute to a better understanding of nitrogen dynamics under varying water levels and environmental conditions, providing valuable insights into the patterns of nitrogen migration and transformation in small-scale soil column experiments

Modification of dentin surface to enamel-like structure: A potential strategy for improving dentin bonding durability, desensitizing and self-repairing

Introduction: Current theories of dentin bonding are based on the concept of "hybrid layer". However, the histological complexity of dentin, as well as the vulnerability of the hybrid layer, goes against the long-term effect of dentin bonding. At the same time, post-operative sensitivity is more likely to occur after traditional adhesive restoration. The Hypothesis: Compared to dentin bonding, enamel bonding exhibits a more optimal immediate and long-term performance, owing to its higher degree of mineralization, well-arranged enamel crystals and the porous structure after etching. Moreover, "enamel hypersensitivity" is never going to happen due to the lack of tubules existing in dentin. In light of this phenomenon, we brought up the concept and the proposal method to form an "enamel-like" dentin, simulating enamel structure to achieve satisfying durability of dentin bonding and obtain good performance for preventing post-operative sensitivity. With the application of mesoporous silicon bi-directionally binding to hydroxyapatite of dentin itself and hydroxyapatite nanorods synthetized in vitro, we may be able to form an enamel-like "functional layer" via ion-regulating self-assembly. Evaluation of Hypothesis: This paper explains how to achieve dentin enamel-like modification by chemical methods, especially, details the strategies and possible mechanisms of the hypothesis. Validation of the hypothesis is more likely to eliminate the adverse effect of dentinal fluid, improve long-term performance of dentin bonding, offer strategies for desensitizing treatment and self-repairing carious-affected dentin, and furthermore, provide the possibility to introduce new theories of dentin bonding

Bioinspired Photo-Responsive Liquid Gating Membrane

Stomata in the plant leaves are channels for gas exchange between the plants and the atmosphere. The gas exchange rate can be regulated by adjusting the opening and closing of stoma under the external stimuli, which plays a vital role in plant survival. Under visible light irradiation, the stomata open for gas exchange with the surroundings, while under intense UV light irradiation, the stomata close to prevent the moisture loss of plants from excessive transpiration. Inspired by this stomatal self-protection behavior, we have constructed a bioinspired photo-responsive liquid gating membrane (BPRLGM) through infusing the photo-responsive gating liquid obtained by dissolving the azobenzene-based photo-responsive surfactant molecules (AzoC8F15) in N,N-Dimethylacetamide (DMAC) into nylon porous substrate, which can reversibly switch the open/closed states under different photo-stimuli. Theoretical analysis and experimental data have demonstrated that the reversible photoisomerization of azobenzene-based surfactant molecules induces a change in surface tension of the photo-responsive gating liquid, which eventually results in the reversible variation of substantial critical pressure for gas through BPRLGM under alternating UV (PCritical (off)) and visible (PCritical (on)) light irradiations. Therefore, driven by a pressure difference ΔP between PCritical (on) and PCritical (off), the reversible switches on the open/closed states of this photo-responsive liquid gating membrane can be realized under photo-stimuli. This bioinspired membrane with switchable open/closed liquid gating performance under photo-stimuli has the opportunity to be used in the precise and contactless control of microfluidics