[Relationship Between the Composition of Soil Aggregates and the Distribution of Organic Carbon Under Long-Term Abandoned Restoration].

Soil aggregates are important carriers of soil organic carbon (SOC) accumulation, and play an important role in the evaluation of soil structure and quality. Natural recovery can promote change in soil aggregate structure and quantity via the redistribution of SOC in the aggregates. Natural restoration from farmland is an important vegetation restoration model on the Loess Plateau. The changes in soil aggregate structure and soil carbon stock after natural restoration have received extensive attention. However, little is known about the continuous study of soil changes on the abandoned grassland during the recovery process. Therefore, to understand how SOC accumulates in the process of natural recovery and quantitatively analyze the contribution of aggregates to the total soil carbon pool, we selected four abandoned grasslands of different restoration ages on the Loess Plateau, China, and studied the changes in soil structure, soil total organic carbon (TOC), soil C:N, soil aggregate distribution, soil aggregate stable index (mean weight diameter, MWD; geometric mean diameter, GMD), and aggregate-associated SOC changes as well as their correlations from 0-20 cm and 20-40 cm soil layers in abandoned grasslands. In addition, we calculated the contribution of aggregates with different sizes to soil TOC stock. The results showed that:① natural restoration increased the macroaggregate amount, MWD, and GMD, but decreased the amount of microaggregate and silt-and clay-sized fractions. There are significant differences in the distribution and stability of aggregates between different soil layers; the promotion effect of the surface was higher than that of the subsurface soils. ② In the 42 years after abandoning recovery, soil TOC stock, macaggregate-and mesaggregate-associated SOC stock increased significantly, and varied with soil depth and years of abandonment (1.92 times, 10.2 times, and 3.61 times). In contrast, micaggregate-associated SOC stock decreased significantly, and silt-and clay-sized fractions-associated SOC stock showed no distinct change. In addition, natural restoration promoted the ratio of C:N; nevertheless, the ratio of C:N under the surface showed a reduced phenomenon after 42 years of abandonment. ③ The improvement in soil TOC stock depends primarily on changes in the macaggregate-associated organic carbon stocks, which account for 80% of macaggregate, and the significant increase in the amount of macaggregate is the main reason for the high contribution.The results of our study suggest that natural restoration is conducive to the accumulation of soil organic carbon, and improvement in soil structure and stability. Macroaggregate is the key factor in soil organic carbon accumulation and soil structure improvement in the process of natural restoration.

Influence of relative wall thickness on electrocardiographic voltage measures in left ventricular hypertrophy: a novel factor contributing to poor diagnostic accuracy.

Objective: To characterize the influence of relative wall thickness (RWT) on Cornell, Sokolow-Lyon and Peguero-Lo Presti voltages and elucidate its potential impacts on their diagnostic accuracy for LVH in a large general Chinese population.Methods: A total of 10,614 permanent residents aged ≥ 35 years were recruited for this study. All the participants were subjected to ECG and echocardiogram during the same visit. Multivariate linear and logistic regression analyzes were conducted to assess the influence of RWT on the voltages and their diagnostic performance for LVH detection.Results: A distinct correlation was identified between RWT and Cornell and Peguero-Lo Presti voltages following adjustments for age, gender and left ventricular mass (LVM) (ß = 0.675 and 1.342, respectively; Ps < 0.001). Besides, subjects with RWT > 0.42 exhibited higher rates of LVH diagnosed by Cornell (OR = 1.78, 95% CI: 1.45-2.20), Sokolow-Lyon (OR = 1.30, 95% CI: 1.08-1.56), and Peguero-Lo Presti voltage (OR = 1.48, 95% CI: 1.29-1.70) after adjustments for age, gender and echocardiographic LVH. Furthermore, concentric remodeling or concentric hypertrophy displayed higher rates of LVH diagnoses via Cornell and Peguero-Lo Presti voltage criteria, as compared with normal geometry or eccentric hypertrophy, respectively (all Ps < 0.05), findings of which were independent of age, gender and LVMI.Conclusion: Echocardiographic RWT was independently correlated with electrocardiographic voltage measures of LVH, which influenced their positive rates and contributed to poor diagnostic performance.

Independent Influence of Blood Pressure on QTc Interval: Results from a General Chinese Population.

AIMS: We performed the current study primarily to characterize the independent association of blood pressure with heart rate-corrected QT (QTc) interval after adjusting for cardiovascular confounding factors and left ventricular mass (LVM) in a large general population in China. METHODS: All enrolled 10,553 permanent residents with age ≥ 35 years from Liaoning Province were investigated by a questionnaire and then subjected to physical examinations, laboratory analyses, and electrocardiogram (ECG) as well as echocardiogram at the same visit. Multivariate linear and logistic regression analyses were conducted to assess the independent association of blood pressure with QTc interval. RESULTS: Hypertensive subjects had significantly longer QTc interval and higher prevalence of prolonged QTc interval compared with normotensive ones in all subgroups stratified by gender and left ventricular hypertrophy (LVH) (all Ps ≤ 0.001). Multiple relevant clinical confounding factors and LVM were all adjusted in the multivariate linear and logistic regression analyses. As a result, both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were independently associated with QTc interval (ß = 0.12 and 0.16, respectively; Ps < 0.001). Furthermore, as categorical variables, hypertension was independently associated with prolonged QTc interval (OR = 1.71; P < 0.001). Sex-specific analyses revealed that the independent associations were detected in both males and females (all Ps < 0.001). CONCLUSIONS: These key findings of the current study highlighted the fact that hypertension was significantly associated with prolonged QTc interval and the correlations were independent of confounding factors and LVM.

10-year ASCVD risk is positively correlated with depressive symptoms in a large general population.

BACKGROUND: To explore the potential correlation between 10-year atherosclerotic cardiovascular disease (ASCVD) risk and depressive symptoms in a general population. METHODS: A cross-sectional study involving 11,956 permanent residents of Liaoning Province in China ≥35 years of age was conducted. Depressive symptoms were assessed with the Patient Health Questionnaire-9 (PHQ-9) while 10-year ASCVD risk was calculated using the tool suitable for China. RESULTS: Males had significantly higher 10-year ASCVD risk than females (14.2 ± 10.7% vs. 9.3 ± 9.1%; P <  0.001) but lower PHQ-9 score (2.34 ± 3.13 vs. 3.63 ± 4.02; P <  0.001). The mean PHQ-9 score increased significantly with advancing 10-year ASCVD risk category in both males (from 2.03 to 2.61; P for trend < 0.001) and females (from 3.04 to 4.61; P for trend < 0.001), and the increasing trend was more apparent in females (P <  0.001). Pearson correlation analyses showed that 10-year ASCVD risk positively correlated with PHQ-9 score in both sexes (Ps <  0.001). In multivariate linear regression analyses adjusting for confounding risk factors, the independent associations of 10-year ASCVD risk with PHQ-9 score were all significant in the total (ß = 2.61; P <  0.001), male (ß = 1.64; P = 0.001), and female subjects (ß = 3.71; P <  0.001). Further, the interaction analysis proved the impacts of 10-year ASCVD risk on PHQ-9 score were more apparent in females than males (Ps < 0.001). CONCLUSIONS: The 10-year ASCVD risk was positively associated with depressive symptoms in both males and females, which was more apparent in the latter. These findings provided some novel data about the value of 10-year ASCVD risk in estimating depressive symptoms.