[Seasonal Regulation of Soil Microbial Carbon and Phosphorus Metabolisms in an Apple Orchard: Evidence from the Enzymatic Stoichiometry Method].

Soil microbial carbon (C), nitrogen (N), and phosphorus (P) nutrient requirements and metabolic limitations are closely related to the availability of environmental nutrients. However, it is unclear how manure and chemical fertilization shift nutrient limitations for microbes in terms of the soil enzymatic stoichiometry in an apple orchard. Therefore, based on the long-term experiment located in an apple orchard established in 2008, this study applied the theory and method of soil enzyme stoichiometry to systematically investigate the effects of the combined application of manure and chemical fertilizers on soil C, N, and P turnover-related enzyme activities (ß-1,4-glucosidase, BG; leucine aminopeptidase, NAG; ß-1,4-N-acetylglucosaminidase, LAP; and acid or alkaline phosphatase, PHOS) and their stoichiometric characteristics and analyzed their relationships with environmental factors and microbial carbon use efficiency. The experiment was designed with four treatments, such as, no fertilization input as the control (CK), single application of chemical fertilizer (NPK), combined application of manure and chemical fertilizer (MNPK), and single application of manure (M). The results revealed that:① at different growth stages of fruit trees, the soil microbial biomass C (microC) content of manure fertilizer treatments (MNPK and M) was significantly higher than that of no manure fertilizer treatments (CK and NPK). The content of microbial biomass N (microN) in the NPK, MNPK, and M treatments increased by 89%, 269%, and 213%, respectively, compared with that in CK (P<0.05). ② Compared with those in the fertilization treatments, CK had higher leaf N and P contents (29.8 g·kg-1 and 2.17 g·kg-1) at the germination stage, and the leaf P content at the germination stage alone was significantly negatively correlated with soil available phosphorus (AP) content. ③ Soil enzyme stoichiometry analysis demonstrated that all data points in this study were above the 1:1 line, indicating that microbial communities had a strong phosphorus limitation. The range of vector length and angle was 0.56-0.79 and 59.3°-67.7°, respectively, in the growth period of fruit trees, and the vector angle was >45° in this study, which also reflected the strong phosphorus limitation of microorganisms. ④ RDA and random forest model analysis showed that organic carbon and available nitrogen (AN) were the main physical and chemical factors affecting vector length; AP, AN, and soil water content were the main physical and chemical factors affecting vector angle. Combined with SEM analysis, AN and dissolved organic carbon (DOC) directly affected microC and microN, AP directly affected microP and microN, DOC and AP directly affected vector length, and AP and microN directly affected vector angle. In addition, microbial carbon utilization was positively correlated with vector length and negatively correlated with vector angle. In summary, the combined application of manure and chemical fertilizers regulated microbial carbon and phosphorus metabolism by affecting soil carbon and phosphorus content at different growth stages of fruit trees, thereby affecting microbial carbon utilization. This study provides a scientific basis for manure and chemical fertilizers to improve soil quality and maintain soil health.

[Effects of Long-term Combined Application of Organic and Inorganic Fertilizers on Soil Carbon Pool and Greenhouse Gas Emissions in Orchards].

Applying organic fertilizer can increase the contents of soil organic carbon (SOC) and active organic carbon, which are crucial for strengthening soil quality and fertility. Four treatments were established:no fertilization (CK), single application of organic fertilizer (M), single application of chemical fertilizer (NPK), and combined application of organic and inorganic fertilizers (MNPK). The changes in SOC and active components under long-term combined application of organic and inorganic fertilizers were investigated, as were the effects of various fertilization measures on greenhouse gas emissions. Moreover, we evaluated the variation in the soil carbon pool management index (CPMI). Total organic carbon (TOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), easily oxidized organic carbon (EOC), and particulate organic carbon (POC) increased by 82.84%, 66.30%, 21.12%, 93.28%, and 145.80%, respectively, when compared to those in the CK treatment. The NPK treatment had no discernible effect on SOC and organic carbon components. The combined application of organic and inorganic materials could enhance LI, CPI, and the soil carbon pool management index, with the increase in LI and CPI being the primary reason for the increase in CPMI. Correlation analyses revealed that soil organic carbon components and CPMI were significantly positively correlated with greenhouse gas emissions. The combined application of organic and inorganic materials enhanced cumulative CO2 emissions and warming potential (GWP) but decreased GHGI and yielded a maximum of 56365 kg·hm-2. Compared with that in the CK treatment (29073 kg·hm-2), apple yield in MNPK increased by 93.87%. Therefore, applying organic and inorganic fertilizers in dryland apple orchards can improve the accumulation of organic carbon and stabilize the soil carbon pool, which is more beneficial to the sustainable development of orchards.

Depression at Baseline Is an Independent Risk Factor for Cognitive Decline in Patients on Peritoneal Dialysis: A Multicenter Prospective Cohort Study.

Background:Depression has been recognized as a risk factor for cognitive impairment (CI) from cross-sectional datasets. This multicenter prospective study investigated the association between depression and cognitive decline in peritoneal dialysis (PD) patients.Methods:This multicenter prospective cohort study included 458 PD patients who were followed up for 2 years. The Modified Mini-Mental State Examination (3MS) was used for assessment of global cognitive function, Trail-Making Tests A and B for executive function, subtests of the Battery for the Assessment of Neuropsychological Status for immediate and delayed memory, visuospatial skill, and language ability. Depression was assessed using Zung's Self-Rating Depression Scale.Results:During the 2-year follow-up, patients with moderate/severe depression at baseline showed a significant decline in global cognitive function (80.5 ± 15.2 vs 76.6 ± 15.5, p = 0.008), while patients without depression or with mild depression kept a stable global cognitive function. In the meantime, patients without depression showed significant improvements in immediate memory, visuospatial skill, and language ability. However, no significant improvement in these parameters was shown in depression groups. In multivariable linear regression analysis, depression at baseline was a significant predictor of worsening global cognitive function, whether depression was analyzed as a continuous variable (odds ratio [OR] = -0.14, 95% confidence interval [CI] -0.27, -0.01, p = 0.031) or a rank variable (OR = -1.88, 95% CI -3.30, -0.45, p = 0.010). Moreover, higher depression score or more severe depression degradation was significantly associated with decline of immediate memory, delayed memory, and language skill.Conclusion:Depression was a significant risk factor for worsening of CI in PD patients.

The Association of Cognitive Impairment with Peritoneal Dialysis-Related Peritonitis.

Background:Research on the association between cognitive impairment (CI) and peritoneal dialysis (PD)-related peritonitis is limited. Therefore, we investigated whether CI contributed to the risk of PD-related peritonitis.Methods:This prospective cohort study enrolled 458 patients from 5 PD centers between 1 March 2013, and 30 November 2013, and continued until 31 May 2016. We used the Modified Mini-Mental State Examination (3MS) to assess general cognition, the Trail-Making Test to assess executive function, and subtests of the Battery for the Assessment of Neuropsychological Status to assess immediate and delayed memory, visuospatial skills, and language ability. Patients were assigned to CI and non-CI groups based on their 3MS scores. The first episode of peritonitis was the primary endpoint event. Treatment failure of peritonitis was defined as peritonitis-associated death or transfer to hemodialysis. We used competing risk models to analyze the association between CI and the risk of peritonitis. The association of CI with treatment failure after peritonitis was analyzed using logistic regression models.Results:Ninety-four first episodes of peritonitis were recorded during a median follow-up of 31.4 months, 18.1% of which led to treatment failure. No significant group differences were observed for the occurrence, distribution of pathogenic bacteria, or outcomes of first-episode peritonitis. Immediate memory dysfunction was independently associated with a higher risk of PD-related peritonitis (hazard ratio [HR] 1.736, 95% confidence interval [CI] 1.064 - 2.834, p < 0.05), adjusting for confounders.Conclusions:Immediate memory dysfunction was a significant, independent predictor of PD-related peritonitis. Neither general nor specific domains of CI predicted treatment failure of peritonitis.

Cognitive Changes in Peritoneal Dialysis Patients: A Multicenter Prospective Cohort Study.

RATIONALE & OBJECTIVE: Cognitive impairment is an independent predictor of technique failure and mortality in patients on peritoneal dialysis (PD) therapy. We investigated changes in cognitive function and factors associated with it in this population. STUDY DESIGN: Multicenter prospective cohort study. SETTING & PARTICIPANTS: 458 PD patients were enrolled and followed up for 2 years. PREDICTORS: Global and specific domains of cognitive function were measured at baseline and after 2 years. The Modified Mini-Mental State Examination (3MS) was used for assessment of global cognitive function; Trail-Making Tests A and B, for executive function; and subtests of the Battery for the Assessment of Neuropsychological Status, for immediate and delayed memory, visuospatial skill, and language ability. OUTCOMES: The primary outcome was change in cognitive function. Secondary outcomes included all-cause mortality, cardiovascular mortality, hospitalization, and transition to hemodialysis therapy. ANALYTICAL APPROACH: Multivariable linear regression models. RESULTS: The prevalence of cognitive impairment increased from 19.8% to 23.9%. 3MS scores significantly decreased (84.8 to 83.1), although executive function, immediate memory, and visuospatial skill improved over time. Delayed memory capacity and language ability were unchanged. Lower serum albumin level was associated with deteriorated delayed memory, visuospatial skill, and language ability, as well as with the decline in general cognitive function (ß values of 0.64, 0.90, 0.80, and 0.44, respectively). Advanced age, lower education, and depression were also correlated with deterioration in general and specific cognitive function. After multivariable adjustment, both global and specific cognitive impairment at baseline were associated with a greater rate of hospitalization, and memory dysfunction was associated with a lower dialysis modality survival rate. LIMITATIONS: A relatively short observation period, small number of deaths, and potential selection bias due to patients unavailable for the second assessment. CONCLUSIONS: In a PD population, global cognitive function declined over 2 years, though some specific cognitive domains improved. Besides well-recognized factors, hypoalbuminemia and depression were also risk factors for cognitive impairment.

[Effects of grass cover combined with different fertilization regimes on soil nutrients and enzyme activities in apple orchard in Weibei dryland, China.] / æ¸­åŒ—æ—±åœ°è‹¹æžœå›­ç”Ÿè‰è¦†ç›–ä¸‹ä¸åŒè‚¥æ–™é æ–½å¯¹åœŸå£¤å »åˆ†å’Œé ¶æ´»æ€§çš„å½±å“.

The split-plot design was adopted in this experiment, with main treatments of grass cover and control and sub-treatments included four fertilization regimes: no fertilization, CK; manure, M; N,P and K fertilizer, NPK; and NPK fertilizer combined with manure, MNPK. Microplate fluorimetry was used to study the effects of grass cover combined with different fertilization regimes on the enzyme activities in apple orchard. The results showed that after mowing the grass (the residues were left on the soil surface as mulch), the soil water content, available P, nitrite nitrogen and the activities of ßX, NAG, ßG, CBH were increased compared to the control, with no significant differences for total nitrogen, soil organic carbon, and AKP activity. For grass cover treatment, the total nitrogen, soil organic carbon, and the activities of ßX, NAG, ßG, CBH, AKP were both improved before and after mowing the grass. However, the soil water content, available phosphorus, and nitrate nitrogen of grass cover treatment were lower than that of the control before mowing the grass. Under grass cover condition, the total nitrogen, available P, and soil organic carbon of M and MNPK were higher than that of CK and NPK in both before and after mowing the grass periods, with the activities of ßX, NAG, ßG, CBH, AKP of MNPK higher than that of NPK. Under the control condition, the available P, soil organic carbon (SOC), nitrite nitrogen, total nitrogen and the activities of ßG, CBH, AKP of MNPK higher than that of CK and NPK before and after mowing the grass. Redundancy analysis showed that the activities of soil enzymes were significantly correlated with the soil nutrients, and could reflect the soil fertility. Thus, grass cover combined with MNPK significantly increased the soil nutrient contents and soil enzyme activities, and was an important practice to prevent the decrease of soil fertility and benefit the sustainability of local apple industry.

An association of cognitive impairment with diabetes and retinopathy in end stage renal disease patients under peritoneal dialysis.

BACKGROUND: Diabetes and retinopathy have been considered as risk factors of cognitive impairment (CI) in previous studies. We investigated both of these two factors and their relationship with global and specific cognitive functions in end stage renal disease patients under peritoneal dialysis (PD). METHODS: In this multicenter cross-sectional study, 424 clinically stable patients were enrolled from 5 PD units, who performed PD for at least three months and completed fundoscopy examination if they had diabetes. Global cognitive function was measured using the Modified Mini-Mental State Examination (3MS), Trail-Making Test forms A and B for executive function, and subtests of the Battery for the Assessment of Neuropsychological Status for immediate and delayed memory, visuospatial skills, and language ability. RESULTS: PD Patients with DM and Retinopathy had significantly higher prevalence of CI, executive dysfunction, impaired immediate memory and visuospatial skill, compared with patients in non-DM group. By multivariate logistic regression analyses, DM and retinopathy rather than DM only were significantly associated with increased risk for CI, executive dysfunction, impaired immediate memory and visuospatial skill, odds ratios(ORs) and 95% confidence intervals were 2.09[1.11,3.92], 2.89[1.55,5.37], 2.16 [1.15,4.06] and 2.37[1.32,4.22], respectively (all P < 0.05). CONCLUSIONS: Diabetic PD patients with retinopathy were at two times risk for overall cognitive impairment, executive dysfunction, impaired immediate memory and visuospatial skill as compared to non-diabetic PD patients.

Performance of the Modified Mini-Mental State Examination (3MS) in Assessing Specific Cognitive Function in Patients Undergoing Peritoneal Dialysis.

PURPOSE: While Cognitive impairment (CI) has been identified as an independent risk factors for mortality in patients undergoing peritoneal dialysis (PD), it is inadequately assessed. We evaluated the applicability of the Modified Mini-Mental State Examination (3MS) in assessing specific cognitive function and compared it to a detailed neuropsychological test battery as the reference standard. METHODS: In this multicentric cross-sectional study, we enrolled 445 clinically stable patients from five PD units, who were undergoing PD for at least 3 months. The 3MS was evaluated for general cognitive function. A detailed neuropsychological battery including domains of immediate memory, delayed memory, executive function, language, and visuospatial ability were evaluated as reference standards. Sensitivity and specificity of the 3MS was determined by using receiver operating characteristic (ROC) analysis. RESULTS: The CI prevalence evaluated by 3MS was 23.6%. PD patients with CI performed worse in all cognitive domains. The 3MS correlated well with specific cognitive domains. However, 18.5%, 57.4%, 12.6%, 8.8%, and 41.2% of patients whom were idendified as normal by 3MS still showed executive dysfunction, immediate memory impairment, delayed memory impairment, and language-ability and visuospatial-ability impairment, respectively. The 3MS identified patients having specific cognitive dysfunction with varied extent of diagnostic value, with 0.50, 0.42, 0.35, 0.34, and 0.26 of Youden index in executive function, delayed memory, language ability, immediate memory, and visuospatial ability, respectively. CONCLUSIONS: The 3MS is not a comprehensive instrument for major cognitive domains in PD patients. It could, however, be used for executive dysfunction and delayed memory impairment screening.

Depression and Cognitive Impairment in Peritoneal Dialysis: A Multicenter Cross-sectional Study.

BACKGROUND: Depression and cognitive impairment have been identified as independent risk factors for mortality in peritoneal dialysis (PD) patients. The relationship between depression and global and specific cognitive functions in PD patients was investigated in this study. STUDY DESIGN: Multicenter cross-sectional study. SETTING & PARTICIPANTS: 458 clinically stable patients, drawn from 5 PD units, who performed PD for at least 3 months were enrolled. PREDICTOR: Depression, defined as depression severity index score > 0.5 using the Zung Self-rating Depression Scale. OUTCOMES: Global and specific cognitive impairment. Global cognitive function was measured using the Modified Mini-Mental State Examination (3MS), Trail-Making Test forms A and B for executive function, and subtests of the Battery for the Assessment of Neuropsychological Status for immediate and delayed memory, visuospatial skills, and language ability. RESULTS: Prevalences of depression and cognitive impairment evaluated by the 3MS were 52% and 28.4%, respectively. Patients with mild or moderate/severe depression had higher prevalences of general cognitive impairment, executive dysfunction, and impaired immediate and delayed memory. After adjusting for demographics, comorbid conditions, and clinical parameters, depression scores were independently associated with lower 3MS scores, lower immediate and delayed memory and language ability scores, and longer completion times of Trails A and B. Even mild depression was independently associated with higher risk for cognitive impairment, executive dysfunction, and impaired immediate and delayed memory after multivariable adjustments. LIMITATIONS: The causal relationship between depression and cognitive impairment could not be determined, and the potential copathogenesis behind depression and cognitive impairment was not fully investigated. CONCLUSIONS: Even mild depression is closely associated with global and specific cognitive impairment in PD patients.

Hyponatremia and Cognitive Impairment in Patients Treated with Peritoneal Dialysis.

BACKGROUND AND OBJECTIVES: Hyponatremia has been identified as a relevant factor for cognitive impairment but has not been investigated in patients receiving peritoneal dialysis (PD). This study investigated the relationship between hyponatremia and cognitive functions in PD patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A total of 476 clinically stable patients from five PD units who were older than 18 years of age and had undergone PD for at least 3 months between March 2013 and March 2014 were enrolled in this multicenter cross-sectional study. Global cognitive function was measured using the Modified Mini-Mental State Examination (3MS); executive function, by trail making tests A (trails A) and B (trails B); and immediate memory, delayed memory, and language ability, by subtests of Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Hyponatremia was defined as serum sodium level ≤135 mmol/L, which was calculated as the mean of measurements taken over the preceding 3 months. RESULTS: Fifty patients (10.5%) had hyponatremia; these patients tended to be older and less educated, to have less inflammation, and to have the higher prevalence of cognitive impairment. They also had lower scores on RBANS subtests. After adjustment for demographic and clinical confounders, hyponatremia was independently associated with lower 3MS score (coefficient, -5.28; 95% confidence interval [CI], -8.44 to -2.13) and longer completion time of trials A (coefficient, 22.68; 95% CI, 3.44 to 41.92) and B (coefficient, 45.56; 95% CI, 1.30 to 89.81). After additional adjustment for laboratory measures, hyponatremia was still associated with 3MS score and completion time of trails A. Hyponatremia was independently associated with CI (odds ratio, 2.17; 95% CI, 1.02 to 4.94) and executive dysfunction (odds ratio, 2.43; 95% CI, 1.01 to 5.87) using multivariate logistic regression analysis. Sensitivity analyses with multivariable models that included propensity score still supported the association between hyponatremia and cognitive impairment. CONCLUSIONS: Hyponatremia was associated with global and specific cognitive impairment in PD patients.