Longitudinal Association between Selenium Levels and Hypertension in a Rural Elderly Chinese Cohort

Objectives Results from previous studies have been inconsistent on the association between selenium and hypertension, and very few studies on this subject have focused on the elderly population. The purpose of this study is to examine the relationship between selenium level and hypertension in a rural elderly Chinese cohort. Design A longitudinal study was implemented and data were analyzed using logistic regression models and Cox proportional hazards regression model adjusting for potential confounders. The associations between selenium level and prevalent hypertension at baseline and between selenium and incident hypertension were examined. Setting Community-based setting in four rural areas in China. Subjects A total of 2000 elderly aged 65 years and over (mean 71.9±5.6 years) participated in this study. Measurements Nail selenium levels were measured in all subjects at baseline. Blood pressure measures and self-reported hypertension history were collected at baseline, 2.5 years and 7 years later. Hypertension was defined as systolic blood pressure 140 mmHg or higher, diastolic blood pressure 90 mmHg or higher, or reported use of anti-hypertensive medication. Results The rate of baseline hypertension was 63.50% in this cohort and the mean nail selenium level is 0.413±0.183µg/g. Multi-covariate adjusted cross-sectional analyses indicated that higher selenium level was associated with higher blood pressure measures at baseline and higher rates of hypertension. For the 635 participants with normal blood pressure at baseline, 360 had developed hypertension during follow-up. The incidence rate for hypertension was 45.83%, 52.27%, 62.50%, 70.48%, and 62.79% from the first selenium quintile to the fifth quintile respectively. Comparing to the lowest quintile group, the hazard ratios were 1.41 (95%CI: 1.03 to1.94), 1.93 (95%CI: 1.40 to 2.67), 2.35 (95%CI: 1.69 to 3.26) and 1.94 (95%CI: 1.36 to 22.77) for the second selenium quintile to the fifth quintile respectively. Conclusions Our findings suggest that high selenium may play a harmful role in the development of hypertension. Future studies are needed to confirm our findings and to elucidate a plausible biological mechanism

Selenium level and depressive symptoms in a rural elderly Chinese cohort

BACKGROUND: Selenium is considered a protective agent against free radicals through the maintenance of better enzyme activity. The few studies examining the relationship between selenium and depression have yielded inconsistent results and none of these studies considered the role of cognitive function in this context. METHODS: A cross-sectional evaluation of 1737 rural Chinese age 65 and over from two provinces in China was conducted. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). Cognitive function was assessed using various cognitive instruments. Selenium measures were obtained from nail samples. Other information collected included demographic characteristics and medical history. Analysis of covariance models were used to identify factors associated with GDS score. RESULTS: Higher selenium levels were associated with lower GDS scores adjusting for demographic and medical conditions (p = 0.0321). However, the association between selenium and depressive symptoms was no longer significant when cognitive function score was adjusted in the model (p = 0.2143). CONCLUSIONS: Higher selenium level was associated with lower depressive symptoms without adjusting for cognition in this cohort. However, after cognition was adjusted in the model the association between selenium and depressive symptoms was no longer significant, suggesting that selenium’s association with depressive symptoms may be primarily through its association with cognitive function

The relationship between cholesterol and cognitive function is homocysteine-dependent

Introduction Previous studies have identified hyperlipidemia as a potential risk factor for dementia and Alzheimer’s disease. However, studies on cholesterol measured in late-life and cognitive function have been inconsistent. Few studies have explored nonlinear relationships or considered interactions with other biomarker measures. Methods A cross-sectional sample of 1,889 participants from four rural counties in the People’s Republic of China was included in this analysis. Serum total cholesterol, high-density lipoprotein, triglycerides, and homocysteine levels were measured in fasting blood samples. A composite cognitive score was derived based on nine standardized cognitive test scores. Analysis of covariance models were used to investigate the association between biomarker measures and the composite cognitive scores. Results There was a significant interaction between the homocysteine quartile group and the cholesterol quartile group on cognitive scores (P=0.0478). In participants with normal homocysteine levels, an inverse U-shaped relationship between total cholesterol level and cognitive score was found, indicating that both low and high cholesterol levels were associated with lower cognitive scores. In participants with high homocysteine levels, no significant association between cholesterol and cognition was found. Conclusion The relationship between cholesterol levels and cognitive function depends upon homocysteine levels, suggesting an interactive role between cholesterol and homocysteine on cognitive function in the elderly population. Additional research is required to confirm our findings in other populations, and to explore potential mechanisms underlying the lipid–homocysteine interaction

Interface-position-dependent structure evolution and mechanical behavior of corrugated cold rolled Cu/Al clad plate: experiment and simulation

Cu/Al corrugated clad plates were prepared by the novel corrugated cold roll bonding (CCRB) process to investigate the stress states, microstructures and mechanical behaviors of the corrugated clad plate adjacent to various corrugated interface positions by experimental and numerical simulation methods. The results show that the CCRB process induces multiple “cross shear” zones in the rolling deformation zone. This greatly accelerates the plastic deformation of Cu layer and significantly diminishes the deformation difference between Cu and Al dissimilar metals with a result of the reduced warpage amplitude. Also, the microstructure at different positions is obviously different due to the various stress states and deformations. Especially at positions III (trough) and IV (front waist), the elongated grains and fine equiaxed grains are formed under the severe plastic deformation and the shear stress. And the ultimate tensile strength achieves a maximum value of 209.25 MPa at position III (trough), and does the minimum value of 182.43 MPa at position II (back waist). The strength of the Cu/Al corrugated clad plate is affected by both the dislocation strengthening and grain boundary strengthening. When the plastic deformation is severe, the dislocation strengthening mechanism is dominant in Cu matrix, while the fine-grain strengthening mechanism in Al matrix

Geographical Distribution Patterns of Iodine in Drinking-Water and Its Associations with Geological Factors in Shandong Province, China

County-based spatial distribution characteristics and the related geological factors for iodine in drinking-water were studied in Shandong Province (China). Spatial autocorrelation analysis and spatial scan statistic were applied to analyze the spatial characteristics. Generalized linear models (GLMs) and geographically weighted regression (GWR) studies were conducted to explore the relationship between water iodine level and its related geological factors. The spatial distribution of iodine in drinking-water was significantly heterogeneous in Shandong Province (Moran’s I = 0.52, Z = 7.4, p < 0.001). Two clusters for high iodine in drinking-water were identified in the south-western and north-western parts of Shandong Province by the purely spatial scan statistic approach. Both GLMs and GWR indicated a significantly global association between iodine in drinking-water and geological factors. Furthermore, GWR showed obviously spatial variability across the study region. Soil type and distance to Yellow River were statistically significant at most areas of Shandong Province, confirming the hypothesis that the Yellow River causes iodine deposits in Shandong Province. Our results suggested that the more effective regional monitoring plan and water improvement strategies should be strengthened targeting at the cluster areas based on the characteristics of geological factors and the spatial variability of local relationships between iodine in drinking-water and geological factors

Permeability Evolution at Various Pressure Gradients in Natural Gas Hydrate Reservoir at the Shenhu Area in the South China Sea

The sediment of the hydrate reservoir in the Shenhu Area is mainly clayey silt. Its characteristic small particles and poor cementation challenge the quantification of the reservoir permeability during gas production. An accurate description of the seepage mechanism of the clayey-silt reservoir is the basis, and also a difficulty, of effective development of gas in the South China Sea. In this study, four sets of water seepage experiments under different pressure gradients are carried out using the clayey-silt reservoir sediments, in which the fourth sample was subjected to computed tomographic (CT) scans. The experimental results shows that the clayey-silt reservoir has a compression of the pore structure and decreasing permeability with the increasing pressure gradient. CT images are used to show the reduction of pore spaces for fluid flow. When the pressure gradient is less than 3 MPa per meter, the pore structure of the reservoir has minor changes. When the pressure gradient is greater than this value, the pore structure of the reservoir will be quickly compressed. This leads to a rapid decrease in permeability, and the process of permeability reduction is irreversible. The decrease of permeability can be predicted directly by establishing a power law model with the change of porosity. Our experimental results preliminarily reveal the dynamic evolution law of pore structure and permeability of clayey-silt reservoir in the process of gas hydrate exploitation via depressurization. The permeability evolution law at various pressure gradients provides a scientific and reasonable basis of a productivity control system for clayey-silt gas hydrate in depressurized gas production

Mechanisms for microstructural evolution of FeSiCrNi high silicon steel subjected to thermomechanical processing

Fe-6.5 wt% Si high silicon steel alloy presents excellent soft magnetic performances, but a poor plasticity limits its industrial application seriously. In this work, a novel FeSiCrNi alloy with the chemical composition of Fe-6.5Si-2Cr-12Ni (wt%) is designed and subjected to thermomechanical processing including local canning compression at room temperature and annealing at elevated temperatures. It is observed that microstructures of FeSiCrNi specimens with a compression degree of 70 % are dominated by dislocation cells. The microstructural evolution is transformed from static recovery to static recrystallization when FeSiCrNi specimens are annealed from 400 to 700 °C. Grains with high strain energy are successively nucleated via the integration of subgrain boundaries at 600 °C and a pronounced growth of recrystallized grains occurs at 700 °C. In particular, microtextures of the FeSiCrNi alloy essentially consist of γ-fiber ({111}∥ND) and λ-fiber ({100}∥ND) textures during recovery and recrystallization. The intensity of λ-fiber texture is weakened with increasing annealing temperature, while the intensity of γ-fiber which is composed of {111} 〈112〉 and {111} 〈110〉 textures is strengthened. The intensity of {111} 〈112〉 texture within the recrystallized FeSiCrNi grains reaches the maximum value at 700 °C

ADAR1 regulates vascular remodeling in hypoxic pulmonary hypertension through N1-methyladenosine modification of circCDK17

Pulmonary hypertension (PH) is an extremely malignant pulmonary vascular disease of unknown etiology. ADAR1 is an RNA editing enzyme that converts adenosine in RNA to inosine, thereby affecting RNA expression. However, the role of ADAR1 in PH development remains unclear. In the present study, we investigated the biological role and molecular mechanism of ADAR1 in PH pulmonary vascular remodeling. Overexpression of ADAR1 aggravated PH progression and promoted the proliferation of pulmonary artery smooth muscle cells (PASMCs). Conversely, inhibition of ADAR1 produced opposite effects. High-throughput whole transcriptome sequencing showed that ADAR1 was an important regulator of circRNAs in PH. CircCDK17 level was significantly lowered in the serum of PH patients. The effects of ADAR1 on cell cycle progression and proliferation were mediated by circCDK17. ADAR1 affects the stability of circCDK17 by mediating A-to-I modification at the A5 and A293 sites of circCDK17 to prevent it from m1A modification. We demonstrate for the first time that ADAR1 contributes to the PH development, at least partially, through m1A modification of circCDK17 and the subsequent PASMCs proliferation. Our study provides a novel therapeutic strategy for treatment of PH and the evidence for circCDK17 as a potential novel marker for the diagnosis of this disease