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Hemodynamic impact of snoring on carotid artery after stent implantation: the role of oscillation

Zhang Xianghao, Fan Zhenmin, Liu Xiao, Liu Mingyuan, Ye Xia, Deng Xiaoyan

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 1

35--45

EN

Snoring is common in overweight and elderly patients treated by endovascular stenting. Studies have proved a correlation between snoring and carotid stenosis, thus, snoring after carotid artery stenting (CAS) might promote or worsen clinical performance. This study tested this hypothesis by constructing a patient-specific carotid bifurcation model and numerically analyzing hemodynamic changes of the carotid artery under different snoring conditions. These conditions included small and large amplitude, low and high frequency, and different age groups. The results found that high amplitude snoring suppressed the disturbed flow at the stented segment while the downstream region of ICA became more chaotic, accounting for in-stent intimal restenosis and thrombosis. Furthermore, local blood flow patterns of elder groups with snoring symptoms were more likely to be changed due to low-speed flow, increasing the possibility of vascular remodeling and thrombosis. Besides, increased snoring frequency hardly influenced the local disturbed flow. Therefore, older adults should receive medical treatment actively after stenting for high-amplitude snoring as soon as possible to avoid potential adverse events.

2

Effect of exercise rehabilitation on hemodynamic performance after carotid artery stenting: a numerical study

Liu Jiashuai, Fan Zhenmin, Liu Xiao, Xu Xiao, Liu Mingyuan, Ye Xia, Deng Xiaoyan

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 2

3--13

EN

A high in-stent restenosis rate and thrombosis have compromised clinical benefits after vascular stent placement. Exercise rehabilitation after stenting emerges as a promising and practical therapeutic strategy to improve the clinical performance of this therapy, although it remains controversial. The present study aimed to explore the impact of exercise training on hemodynamic performance after vascular stent implantation. Different 3-dimensional computational models based on the patient-specific carotids were constructed to calculate hemodynamic parameters, including flow velocity, time-averaged wall shear (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT). The results demonstrated that exercise training increased TAWSS but decreased OSI and RRT in some cases after the intervention, and high-intensity exercise further suppressed the adverse blood flow. However, exercise training remarkably reduced TAWSS and elevated OSI and RRT in patients with mild stenosis at upstream of stented segment. Additionally, we discovered that the hemodynamic environment change induced by exercise training was not significant compared to the stent position in some cases. Exercise had a less beneficial impact on the disturbed blood flow after the distal common carotid artery (CCA) stenting. These findings highlighted that exercise-induced hemodynamic changes differ under different conditions. The exercise training for the intervention patients should only be performed after a comprehensive vascular function assessment.

3

Effect of fluidized magnetizing roasting on iron recovery and transformation of weakly magnetic iron mineral phasein iron tailings

Li Wenbo, Han Yuexin, Liu Xiao, Shan Yan, Li Yanjun

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

906--916

EN

The eastern tailings of the Anshan mining area are generally categorized as high silicon-bearing iron tailings, and the iron mainly exists in the form of hematite–limonite with an iron grade of 10.60%. In order to recover iron minerals and reduce the influence of the tailings on the environment, a method for pre-enrichment through the combination of low intensity magnetic separation and high intensity magnetic separation with fluidized magnetizing roasting and subsequent low intensity magnetic separation was developed to treat the eastern tailings of the Anshan mining area. The effects of gas-flow rate, H2 concentration, roasting temperature, and roasting time on the quality of the final iron concentrate were discussed. Moreover, the iron phase transformation and change in magnetism of the sample were studied. The results indicated that an iron concentrate with an iron grade of 65.30% and a recovery of 85.85% could be obtained under the conditions of gas-flow rate of 8 m3/h, H2 concentration of 50%, and fluidized magnetizing roasting at 600 ℃ for 20 s. X-ray diffraction analysis, phase analysis, and magnetism analysis on the roasted materials indicated that the hematite–limonite could be transformed into magnetite during the fluidized magnetizing roasting process, and effective separation of iron and gangues could be easily achieved by the weak magnetic separation.

4

Environmental Regulation and Employment: Evaluating the Role of Water Pollution Prevention and Control Law in China

Yu Wei, Liu Xiao

Problemy Ekorozwoju

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2018

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Vol. 13, nr 2

7--16

EN

In this paper, we investigate the impact of environmental regulations on employment in China. We apply a quasi-natural experiment on the revision of Water Pollution Prevention and Control Law in 2008 (WPPCL2008), and we analyze manufacturing sectors’ reaction to WPPCL2008 by using a differences-in-differences approach based on China’s thirty five sectors at the 2-digit level from 2003 to 2014. Our results show that although environmental regulations can reduce waste-water emissions, at the same time cause a decrease in employment. The results suggest that stringent environmental regulation is not cost free. Furthermore, this finding contradicts the popular view that the effect of Chinese legislation enforcement is insignificant.

PL

W tym artykule analizujemy wpływ środowiskowych regulacji prawnych na zatrudnienie w Chinach. Przygotowaliśmy eksperyment odnoszący się do poprawionej Ustawy o zapobieganiu zanieczyszczeniom wody i kontroli jakości wód z 2008 r. (WPPCL2008) i przeanalizowaliśmy reakcję na zmienione prawo ze strony sektora produkcyjnego korzystając z metody DID (differences-in-differences), uwzględniając 35 sektorów występujących w Chinach i 2-cyfowy poziom pomiędzy 2003 a 2014 r. Otrzymane rezultaty pokazują, że surowe regulacje środowiskowej nie są wolne od kosztów. Co więcej, okazuje się, że są one sprzeczne z poglądem, że chińskie prawodawstwo jest nieistotne.