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Introduction: Environmentally friendly and efficient biochar precursor materials and their modification methods are of great significance in solving the problem of soil cadmium pollution. Materials and methods: This study prepared apple pomace biochar (ABC) from discharged apple pomace by pyrolysis at 500 °C. ABC was modified by phosphoric acid impregnation (P-ABC), MnO2 loading (Mn-ABC), and MnO2 loading after phosphoric acid impregnation (Mn-P-ABC). The biochar and modified biochar were described by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. The impacts of original and modified biochar on soil characteristics and the immobilization of original and modified biochar with different additions (4, 7, 10 and 13%) on Cd in contaminated soils were studied. Results and discussion: The outcomes show that ABC, P-ABC, Mn-ABC, and Mn-P-ABC are porous and amorphous materials rich in functional groups. All four types of biochar can enhance soil organic matter content, cation exchange capacity, and pH value, effectively improving soil properties. After application of biochar materials, the extractable Cd in soil was obviously reduced compared to the control, and 13% Mn-P-ABC reduced the extractable Cd in the soil by 43.84%. The results of Cd speciation analysis indicate that after the application of biochar materials, the acid soluble Cd in the soil reduced and the residual Cd increased. Conclusions: The treatment with 13% Mn-P-ABC resulted in a 35.57% decrease in acid soluble Cd in soil and a 30.18% increase in residual Cd, indicating the best immobilization effect on Cd. [ABSTRACT FROM AUTHOR]

Objective: Biodegradable stents represent a new technological development in the field of cardiovascular angioplasty. The stent geometry plays a crucial role in determining stent performance. Methods: This study describes four stent models with various strut geometries (circular, triangular, hexagonal, and spline) and identical links. The performance of the various stents is assessed by modeling the processes of compression and balloon expansion using experimental and numerical techniques. Results: Four adjustable variables related to radial strength, foreshortening rate, maximum expanded diameter and coverage are considered in this studies. The maximum stress distributions from our numerical analysis are in agreement with the experimental fracture measurements. Conclusion: Analysis of the stent parameters indicates that the hexagonal geometry is a relatively good stent strut design. The results described in this paper will be useful in further optimization studies and for the development of stents with a higher radial strength and increased fracture resistance. [ABSTRACT FROM AUTHOR]

Previous animal studies by using tail-suspended hindlimb-unloaded rat model have shown that simulated microgravity-induced vessel structural and functional remodeling may be anatomic region dependent. However, little care has been taken to assess the structural adaptation of the endothelial glycocalyx, the apical surface of the endothelium, the key mechanosensor mediating nitric oxide (NO) production, and the natural protective barrier of the vasculature. Therefore, the present study extended simulated microgravity-induced vessel remodeling to the endothelial glycocalyx level. The percents of bone mineral density (BMD) change from both control and tail-suspended (TS) rats were measured by micro-computed tomography (Micro-CT). Structural parameters such as the luminal diameter (D), the thickness of each layer, the ratio of intima to media (IMR), the cross-sectional areas of the intima (CSA) and media (CSA) of vessels from three different regions (the common carotid artery, abdominal aorta, and femoral artery) were assessed by hematoxylin and eosin staining. Dimensions of the glycocalyx above, below, and away from the endothelial cell nucleus were examined by fluorescein isothiocyanate-labeled wheat germ agglutinin (WGA-FITC) binding to the cryosection of vessels. Our results show that 3-week tail suspension of rats increases the thickness and CSA of the abdominal aortic endothelium by 23.7 and 21.1 %, respectively, thickens the media layer of the common carotid artery by 34.0 %, and increases the luminal diameter, the CSA of the intima and media of the femoral artery by 75.7, 93, and 61.2 %, respectively. Correspondingly, the dimension of the glycocalyx away from the common carotid arterial and the abdominal aortic endothelial cell nucleus from tail-suspended rats shows a 1.66- and 1.64-fold increase respectively, while it shows a 0.79-fold reduction on the top of the femoral endothelial cells. These results suggest that simulated microgravity induces vascular endothelial glycocalyx remodeling in a regional-dependent manner. The perturbation of the endothelial glycocalyx at the lower body artery may be the first event of vascular remodeling initiating endothelial dysfunction, contributing to postspaceflight orthostatic intolerance. [ABSTRACT FROM AUTHOR]

Although multilayer stents (MSs) can be used to treat aneurysm effectively, for some aneurysms with branches attached, the hemodynamic mechanisms are still unclear. In this work, we modeled five cases that involve 1–4-layer stents implanted in aneurysms with side branches, and the numerical approach was used. Case 1 corresponds to an aneurysm without a stent, and cases 2–5 represent 1–4-layer stents being employed within aneurysms, respectively. The results showed that the velocity within the sac declined dramatically and the eddies' intensity weakened with increased number of stent layers, time-averaged wall shear stress (TAWSS), and nitric oxide production rate (TARNO) dropped linearly with increase in stent porosity, and oscillatory shear index (OSI) and relative residence time (RRT) increased evidently with MS intervention. Moreover, the MSs had a slight effect on the patency of the side branch; its flow rate was still above the normal case than without aneurysm. It can be concluded that MSs are helpful in promoting the growth of thrombus within the aneurysm through an isolated hemodynamic environment and keeping the branch unobstructed, but more clinical evidences are required. [ABSTRACT FROM AUTHOR]