Different Responses of Growing Season Ecosystem CO2 Fluxes to Rain Addition in a Desert Ecosystem.

Desert ecosystem CO2 exchange may play an important role in global carbon cycling. However, it is still not clear how the CO2 fluxes of shrub-dominated desert ecosystems respond to precipitation changes. We performed a 10-year long-term rain addition experiment in a Nitraria tangutorum desert ecosystem in northwestern China. In the growing seasons of 2016 and 2017, with three rain addition treatments (natural precipitation +0%, +50%, and +100% of annual average precipitation), gross ecosystem photosynthesis (GEP), ecosystem respiration (ER), and net ecosystem CO2 exchange (NEE) were measured. The GEP responded nonlinearly and the ER linearly to rain addition. The NEE presented a nonlinear response along the rain addition gradient, with a saturation threshold by rain addition between +50% and +100%. The growing season mean NEE ranged from -2.25 to -5.38 µmol CO2 m-2 s-1, showing net CO2 uptake effect, with significant enhancement (more negative) under the rain addition treatments. Although natural rainfall fluctuated greatly in the growing seasons of 2016 and 2017, reaching 134.8% and 44.0% of the historical average, the NEE values remained stable. Our findings highlight that growing season CO2 sequestration in desert ecosystems will increase against the background of increasing precipitation levels. The different responses of GEP and ER of desert ecosystems under changing precipitation regimes should be considered in global change models.

Effect of aeration modes on nitrogen removal and N2O emission in the partial nitrification and denitrification process for landfill leachate treatment.

The anoxic/multi-aerobic process is widely applied for treating landfill leachate with low carbon to nitrogen ratio. In this study, the effect of two aeration modes in the aerobic phase, i.e. decreasing dissolved oxygen (DO) and increasing DO, on nitrogen removal and N2O emission in the process were systematically compared. The results demonstrate that the aerobic phase with increasing DO mode has a positive effect on improved total nitrogen removal (78 %) under the COD/N ratio as low as 3.45 and minimized N2O emission. DO concentration higher than 1.5 mg/L in the aerobic phase reduced nitrogen removal and led to a significant high N2O emission in the process. Complete nitrite denitrification in the anoxic phase correlated with minimized N2O emission. Under efficient nitrogen removal stage, N2O emission factor was 2.4 ± 1.0 % of the total incoming nitrogen. Microbial analysis revealed that increasing DO mode increased the abundance of ammonia oxidizing bacteria and denitrifiers.

Oxidative dehalogenation and mineralization of polychlorinated biphenyls by a resuscitated strain Streptococcus sp. SPC0.

Most functional microorganisms cannot be cultivated due to entering a viable but non-culturable (VBNC) state, which limits the characterization and application of polychlorinated biphenyl (PCB)-degrading strains. Resuscitating VBNC bacteria could provide huge candidates for obtaining high-efficient PCB degraders. However, limited studies have focused on the ability of resuscitated strains for PCBs degradation. In the present study, whole-genome analysis of a resuscitated strain SPC0, and its performances in degradation of three prevalent PCB congeners (PCBs 18, 52 and 77) were investigated. The results indicate that the strain SPC0 belonged to the genus Streptococcus, possessed the degradation potential for aromatic xenobiotics. The SPC0 could effectively degrade PCBs 18 and 52, but exhibited lower degradation efficiency of PCB 77. Degradation of PCBs 18 and 52 could be fitted well by zero-order model, whereas the fittest model for PCB 77 degradation was pseudo second-order kinetics. The bph genes expression, chloride ions release and degradation metabolites identification, suggest that SPC0 possessed the capability of oxidative dehalogenation and mineralization of PCBs. Interestingly, SPC0 can degrade PCBs via the bph-encoded biphenyl pathway, and further mineralize metabolite dichlorobenzoate via protocatechuate pathway. This study is the first to show that a strain belonging to genus Streptococcus possessed PCB-degrading capability, which uncovered the powerful potential of resuscitated strains for bioremediation of PCB-contaminated sites.

The urban-rural disparity in the prevalence and risk factors of hypertension among the elderly in China-a cross-sectional study.

INTRODUCTION: This study aimed to assess the prevalence of hypertension and to explore the disparities of its risk factors among urban and rural elderly. METHOD: Data of hypertensive patients were collected from the China Health and Retirement Longitudinal Study (CHARLS) 2015. Stratified sample households were selected from 450 villages or communities of 150 counties from 28 provinces. Multivariable logistic regression was performed to analyze the factors correlated with hypertension. RESULTS: Prevalence of HBP was 47.6% (95% CI [45.2%-50.1%]) in total and it was close between urban and rural population (48.6% vs 47.2%). Factors associated with HBP were different between urban and rural areas. In urban areas, hypertension was significantly associated with literacy and diabetes in both genders, high BMI level and smoke quitters in males, and physical activity and dyslipidemia in females. In rural areas, hypertension was significantly associated with older age, higher BMI level in both males and females, and dyslipidemia in males. CONCLUSIONS: The prevalence are about the same among urban and rural residents, but their risk factors vary from each other. Disparity in the risk factors between urban and rural population should be taken into consideration for further intervention.

Satisfaction about Patient-centeredness and Healthcare System among Patients with Chronic Multimorbidity.

The aim of the present study was to measure the prevalence of multimorbidity in Bangladesh, India and China, and to assess the relationship between multimorbidity and patient's opinion regarding their involvement in healthcare decision-making and overall satisfaction of healthcare system. Cross-sectional data on 18 696 men and women aged 18 and above were collected from the World Health Survey of World Health Organization (WHO). Outcome variables were subjective rating of (1) healthcare system's ability to involve patients in decision-making, and (2) satisfaction with the way healthcare system runs in the country. Self-reported chronic conditions were used to measure the prevalence of multimorbidity. Out of 9 chronic conditions, back pain, arthritis, and chronic cough appeared to be the most prevalent ones among majority of the participants. About one-third of the participants in China (30.7%) and two-thirds in Bangladesh (66.1%) and India (66.6%) reported having at least one chronic illness. Prevalence of multimorbidity was highest in India (34.3%) followed by Bangladesh (28.8%) and China (14.3%). In Bangladesh, India and China, respectively 70.5%, 41.7%, 61.3% women and 54.5%, 42.8% and 58.8 % men expressed dissatisfaction regarding the way healthcare system runs in their country. In Bangladesh and India, men who were living with multimorbidity were more likely to rate the patient-centeredness as "bad" than those who had no disease illness. This study suggests that the prevalence of multimorbidity was remarkably high especially in Bangladesh and India. Higher likelihood of dissatisfaction about healthcare system among multimorbid patients might be indicative of inadequacy in the provision of care in qualitative and quantitative terms.