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Cadmium (Cd) is associated with telomere length and hypertension, respectively, but the mechanism behind its relationship is unclear. Our study aimed to clarify the role of telomere length in the relationship between Cd and hypertension. A 1:1 matched case-control study was conducted with 213 hypertensive patients and 213 normotensive controls in Taiyuan, Shanxi Province, China, from February and June 2016. General demographic characteristics information and lifestyle were collected using a structured questionnaire. Urine samples were collected to test urinary Cd (UCd) levels and corrected by urinary creatinine (UCr) levels. Peripheral leukocyte absolute telomere length (ATL) was measured using quantitative polymerase chain reaction. Logistic regression was used to screen the influencing factors of hypertension. A mediation effect analysis was used to explore the role of telomere length between Cd exposure and the risk of hypertension. We found that the hypertension group had a significantly higher UCd level compared to the control group (0.91 vs 0.80 μg/g Cr, P 0.01), while ATL showed the opposite relationship (2.36 vs 2.65 kb, P 0.01). The Regression analysis of hypertension identified these significant predictors: family history of hypertension (OR = 3.129, 95% confidence interval (95% CI): 1.767-5.540), Body mass index (BMI, OR = 1.088, 95% CI: 1.023-1.157), total cholesterol (TC, OR = 1.277, 95% CI: 1.024-1.592), UCd (OR = 2.092, 95% CI: 1.179-3.710), ATL (OR = 0.105, 95% CI: 0.025-0.453) and 8-hydroxy-2-deoxyguanosine (8-OHdG, OR = 7.864, 95% CI: 3.516-17.589). Mediating effect analysis revealed that ATL was a potential partial mediating factor between Cd and hypertension. Cd may induce hypertension by affecting telomere length, but this requires further exploration.

Subway transportation is being promoted worldwide to effectively solve urban congestion. However, the vibration induced by subway traffic has caused a major adverse impact on building safety, precision instrument operation and human health. Wave barriers have been proven effective in mitigating ground vibration, whereas they have some limitations in achieving ideal attenuation zone and high efficiency to cover the low-frequency vibration in underground railway system. Based on locally resonant phononic crystals theory, this paper designs three-component locally resonant periodic wave barriers (LRPWBs), and investigates the effects of geometrical and material parameters on the bandgap features in detail. The band structures are calculated using improved plane wave expansion (IPWE), the transmission spectra and vibration modes are obtained by finite element method (FEM). The results indicate LRPWBs are able to give lower and wider bandgap to cover the main frequency of subway environment, which is proved by time and frequency domain analysis. For the bandgap mechanism, the local resonance features of LRPWBs result in the energy conversion between kinetic energy and elastic strain energy, thus the elastic wave energy is localized in resonance unit and then the locally resonant bandgap is created. In addition, the bandgap can be adjusted by carefully selecting proper geometrical and material parameters to actualize low-frequency broadband attenuation. Further studies about multi-oscillator system indicate that the appropriate combination of multiple LRPWBs are conductive to diverse and broad bandgaps. The investigations can provide inspiration for periodic wave barriers design in multi-frequency vibration attenuation field.

The structural expanded polystyrene (EPS) concrete (above 35 MPa) has the potential to be used as metro track bed to reduce and isolate vibration, but its bond behavior is still unclear. This inhibits its application because it is often used in combination with reinforcing bar. In this paper, a class of structural EPS concrete (above 35 MPa) was developed. Based on this, a series of pull-out tests were conducted and the bond behavior of deformed bars in these structural EPS concretes was investigated. In addition, effects of rebar bond length and rebar diameter were analyzed in detail. Experimental results indicate that the structural EPS concrete suffers splitting failure more easily than the conventional concrete (CC). Increase of EPS replacement, rebar bond length or rebar diameter tends to cause the splitting failure of structural EPS concrete. Moreover, with increase of EPS replacement, the failure process is less explosive and more gradual. The stress-slip relationships of the most specimens show three stages, namely linear ascending, non-linear progression, and descending stages. The bond strength of structural EPS concrete is found depended linearly on the power function of its compressive strength, relative cover thickness (c/d) and relative rebar bond length (L/d), respectively. Accordingly, a bond strength prediction model was formulated, and it can precisely predict the bond strength of deformed bars in structural EPS concrete, specimens failing in splitting or splitting-pull out modes, and no fiber added. The results can provide reference for the design of structural EPS concrete.

Locally resonant phononic crystals (LRPCs) have the capacity to adjust elastic waves with the structure sizes much smaller than the incident wavelengths, the unique property is called low-frequency bandgap, but it is not easily applied in practical engineering because of narrow bandgap width. Multilayered LRPCs are helpful in generating several bandgaps, in the meanwhile the designs of multilayered LRPCs proposed in previous study result in the larger filling fraction, whereas the bandwidth of LRPCs increases monotonically with filling fraction, thus the pure contribution of concentric ring configuration to the bandwidth extending is less involved. Keeping the filling fraction constant, this paper carefully designs the microstructure of concentric ring locally resonant phononic crystals, and investigates the effects of structure configuration on the bandgap property. To this end, an updated improved plane wave expansion (UIPWE) method is developed to calculate the band structure, and finite element method (FEM) is used to obtain transmission spectra and vibration mode. The results demonstrate that UIPWE method is valid and is able to give precise outcomes, which is verified by FEM. In addition, the concentric ring configuration equivalently produces dual-oscillator system, relative movements between the oscillators generate coupling effect, thus, the bandgaps can be extended by configurating rightly the microstructure of single cell. Further studies about different models indicate that the combination of smaller inner scatterers and larger inner coating layers are beneficial to wider bandgap. These conclusions presented herein provide insights in the design of three-component PCs in multi-frequency vibration control field.

In this paper, the effects of material parameters on the band gaps of two-dimensional (2D) three-component phononic crystals (PCs) are investigated based on improved plane wave expansion method (IPWE). The theoretical derivation is based on the elastic wave equations, and the effects on band gaps for both in-plane (xy-mode) and anti-plane modes (z-mode) are discussed in detail. Results show that the material parameters directly determining the band gaps include mass density ratio, shear modulus ratio, and Poisson’s ratio for xy-mode, and mass density ratio and shear modulus ratio for z-mode; for the three-component PCs with Bragg gaps, wide band gap appears in the case of large density mismatches and large shear modulus ratio of scatterer to matrix, and the Poisson’s ratio of the matrix has more influence on the band gap; for the three-component PCs with local resonance gaps, wide band gap appears in the case of large mass density ratio of scatterer to matrix and small mass density ratio of coating layer to matrix, large shear modulus ratio of scatterer to matrix and small shear modulus ratio of coating layer to matrix. These conclusions can be used to guide the band gap designing of the three-component PCs.