The multiple structures of xylem vessels in Magnolia provide stable and efficient water transport channels. The structural parameters of xylem vessels were studied in wood sections and in macerated materials. The results showed that the xylem vessels of Magnolia contained a helical thickening structure and a pit structure of a secondary wall, and the end walls had a scalariform perforation plate. The helical thickening and scalariform perforation plate increased the flow resistance of the vessel, and the pit structure decreased the flow resistance of the vessel. There was a close positive correlation between the flow resistance of the vessels and the helical width, the helical height, the thickness of the scalariform perforation plate, the number of holes in the scalariform perforation plate, the length of the pit canal, and the pit spacing. In addition, there was a negative correlation between the flow resistance of the vessels and the helical spacing, the pit vertical diameter, and the pit domain length. Among these structural parameters, the helical height, the number of holes, and the length of pit canal had a greater influence on the flow resistance. The pit structure caused the vessel to produce radial water transport. The radial transmission efficiency increased with the increase in the pit domain length. With no pit membrane in the pit structure of Magnolia, the radial transmission efficiency would be between 43.99% and 53.21%.
C-reactive protein (CRP), an inflammatory marker that statistically predicts future cardiovascular risk, has been reported to be associated with plasma lipid level changes. Whether CRP genetic variants affect lipid metabolism is of importance to investigate. A community-based study population including 2,731 adult subjects aged 18-62 years was used to evaluate the association of CRP gene with dyslipidemia and five tagging SNPs (tagSNPs) were genotyped. Multiple logistic regression was applied to further evaluate relationships between the SNPs and lipid metabolism abnormality and general linear model was applied to compare plasma lipid levels between genotypes. Association analyses indicated that recessive model of SNPs rs876537 and rs4285692 had significant association with elevated HDL after adjustment for covariates. Odds ratio (OR) of rs876537 were 0.60 for HDL > 1.54 versus 1.04-1.54 mmol/L (P = 0.011), as well as, ORs were 0.617 for HDL > 1.83 versus ≤1.35 mmol/L (P = 0.002) and 0.724 for HDL = 1.59-1.83 versus ≤1.35 mmol/L (P = 0.028) respectively. OR of rs4285692 was 0.634 for HDL > 1.83 versus ≤1.35 mmol/L (P = 0.027). Further stratification analysis found significant associations of rs10737175 with elevated HDL (>1.54 vs. 1.04-1.54 mmol/L, OR 0.629 and P = 0.027) and elevated TG (≥1.70 vs. <1.70 mmol/L, ORs of additive and dominant models were 0.628, 0.545 and P values were 0.006, 0.003 respectively) in female. rs4285692 was significantly associated with elevated LDL (≥3.37 vs. <3.37 mmol/L), ORs equaled to 1.532, 2.281 for additive model and recessive model and P values were 0.028, 0.024 respectively in male. Furthermore, quantitative trait analysis indicated the variation T to C of rs876537 significantly affect decreased plasma HDL level (P = 0.014). Our findings suggest that CRP genetic polymorphisms independently had positive association with the risk of HDL, LDL and TG elevating and further replication in other large population and biological function research would be warranted.
The bionic structure drip irrigation emitter (BSDE) is a new-type emitter, by which better hydraulic performances can be obtained. In the present work, twenty-five sets of orthogonal test schemes were implemented to analyze the influence of the geometric parameters of the flow channel on the hydraulic characteristics and energy dissipation efficiency of this emitter. Through numerical simulations and verification tests, the flow index and energy dissipation coefficient were obtained. According to the results, the flow index of the BSDE is 0.4757-0.5067. The energy dissipation coefficient under the pressure head of 5-15 m is 584-1701. The verification test has shown that the relative errors among measured values, simulated values and estimated values are less than 3%, which indicates that the flow index can be estimated reliably.
Orthogonal experiments have mostly been used in the structural optimization of drip irrigation emitter flow channels. To further improve the efficiency of the optimal design, this study used a genetic algorithm to optimize the structure of the bionic pit flow channel. Based on the structural similarity and performance optimization of the torus-margo bordered pit structure, the constitutive equation of the flow channel unit was constructed. The selection, crossover and mutation operators were set by the genetic algorithm, and the objective function value was calculated. The design variables and known variables that met the requirements were put into the computational domain model, and the pit flow channel structure was simulated and optimized. The results showed that there were large low-velocity regions at the junctions and corners of the pit flow channel units at a working pressure of 50 kPa, and no complete low-velocity vortices were observed, indicating that the flow channels had good anti-clogging performance. The distribution of flow velocity on the same cross-section was quite different, which made the flow layers collide and mix, which intensified the loss of energy, indicating that it had a good energy dissipation effect. The multivariate linear regression analysis showed that the four variables of tooth stagger value (j), flow channel angle (θ), tooth spacing (l) and inner and outer boundary spacing (h) had a decreasing degree of influence on the flow index (x). The flow index (x) was negatively correlated with the tooth stagger value (j), flow channel angle (θ) and tooth spacing (l), and positively correlated with the inner and outer boundary spacing (h). The test results of physical samples showed that the average error between the simulation results and the real values was 3.4%, indicating that the accuracy was high, which can provide a basis for the structural optimization design of related pit drip irrigation emitters.
The leaf-vein drip irrigation emitter is a new type of drip emitter based on a bionic structure able to support shunting, sharp turns, and increased dissipation. In the present work, the results of twenty-five tests executed in the framework of an orthogonal design strategy are presented in order to clarify the influence of the geometrical parameters of the flow channel on the hydraulic characteristics of such emitter. The corresponding flow index and head loss coefficient are determined through numerical simulations and model testing. The results show that the flow index of the flow channel is 0.4970∼0.5461, which corresponds to good hydraulic performances. The head loss coefficient of the flow channel is 572.74∼3933.05, which in turn indicates a good energy dissipation effect. The order of influence of the leaf vein flow channel parameters on the flow index can be represented in a synthetic way as a > b > c > d > e, where (a) is the width of the inlet, (b) is the horizontal distance of the front water inlet, (c) is the vertical distance of the inner edge of the front end, (d) is the horizontal distance of the rear water outlet and (e) is the vertical distance of the outer edge of the front end. The flow index increases with d, decreases with a, first decreases, and then increases with b, and first increases and then decreases with the increase of c and e. The coefficient (R 2 ) of the fitted model related to geometric parameters and flow index is 0.9986-0.9999. The relative errors among experimental testing, simulation calculation and predictive estimates are shown to be less than 5%.
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