Investigation of braided stents in curved vessels in terms of "Dogbone" deformation.

"Dogbone" deformation that the diameters of two ends are larger than the middle diameter of the stent under the effect of the balloon expanding, is one of the important standards to evaluate the mechanical properties of vascular stents. It is a huge challenge to simulate and evaluate the "Dogbone" behaviors of braided stents in the curved vessels. In this study, the key work was to investigate the "Dogbone" deformations of braided stents in the curved vessels by designing main parameters including strut diameter, braiding angle, and the circumferential number of unit cell. Based on the "Dogbone" stents in the curved vessels, the impact of "Dogbone" on the fatigue properties of braided stents was analyzed under the pulsatile effect of vessels. The influence of "Dogbone" stents on stress distribution of vascular walls was studied. To evaluate the "Dogbone" behaviors of stents in the curved vessels, the calculation method of "Dogbone" was improved by calculating the centerline and the bus bar of the curved vessels. Braided stents with various parameters (strut diameter t = 100,125 and 152 µm, braiding angle α = 30, 40 and 50°, the circumferential number of unit cell N = 8, 10, and 12) were designed respectively. Numerical simulation method was used to mimic the "Dogbone" deformation after stent expansion. The results showed that strut diameter and braiding angle had more influence on "Dogbone" deformations than the circumferential number of unit cell. "Dogbone" deformation could adversely affect fatigue performance and vascular walls.

[Outcomes in randomized controlled trials of acupuncture for vascular cognitive impairment during recent five years].

The existing problems in the outcomes of randomized controlled trials (RCTs) of acupuncture for vascular cognitive impairment (VCI) during recent five years are analyzed and suggestions are proposed. The RCTs of acupuncture for VCI were selected in PubMed, EMbase, Cochrane Library, Clinical Trials, CNKI database, Wanfang database, VIP database, SinoMed database and Chinese Clinical Trial Registry (ChiCTR) from January 1, 2015 to September 14, 2020. The outcomes were extracted and analyzed. As a result, 21 RCTs were included and the outcomes used were divided into 9 categories: clinical symptom/sign indexes, quality of life indexes, neuroimaging indexes, neuroelectrophysiology indexes, blood biochemical indexes, hemorheology indexes, TCM syndrome score indexes, clinical efficacy indexes, and safety indexes. Among them, the top three of the most used outcomes were clinical symptoms/signs indexes (21, 100.0%), clinical efficacy indexes (14, 66.7%) and quality of life indexes (12, 57.1%). In the RCTs of acupuncture for VCI, attention should be paid to distinguish the primary outcomes and secondary outcomes, adopt objective and standardized efficacy evaluation, and give consideration to report the outcomes of safety, health economic and TCM characteristic indexes.

[Overview of systematic reviews of acupuncture for vascular cognitive impairment].

OBJECTIVE: To overview the methodological quality, report quality and evidence quality of the systematic review (SR) of acupuncture for vascular cognitive impairment ( VCI ). METHODS: The SRs regarding acupuncture for VCI were searched in PubMed, Cochrane Library, EMbase, CNKI, SinoMed, Wanfang and VIP databases. The retrieval period was from the establishment of the database to September 24, 2020. The report quality, methodological quality and evidence quality of the included SRs were evaluated by PRISMA statement, the AMSTAR 2 tool and the GRADE system. RESULTS: A total of 22 SRs were included, including 102 outcome indexes. The methodological quality was generally low, with low scores on items 2, 5, 7, 10, 14, 15 and 16. The report quality was good, with scores ranging from 19 points to 24.5 points. The problems of report quality were mainly reflected in the aspects of structural abstract, program and registration, other analysis and funding sources. The level of outcome indexes of SRs was mostly low or very low, and the main leading factor was limitation, followed by inconsistency and inaccuracy. CONCLUSION: Acupuncture for VCI is supported by low quality evidence of evidence-based medicine, but the methodological quality and evidence body quality of relevant SRs are poor, and the standardization is needed to be improved.

EGb in the Treatment for Patients with VCI: A Systematic Review and Meta-Analysis.

BACKGROUND: Ginkgo biloba extract (EGb) is widely used to treat impairments in memory, cognition, activities of daily living, inflammation, edema, stroke, Alzheimer's dementia, and aging. AIM: We aimed to evaluate the safety and efficacy of EGb in treating vascular cognitive impairment (VCI). METHODS: The systematic review was performed using the latest guidelines. We searched for EGb-related trials up to March 1, 2021, in four Chinese databases, three English databases, and clinical trial registry platforms. Randomized controlled trials (RCTs) were included if the study enrolled participants with VCI. Two reviewers independently extracted the data and critically appraised the study quality. Heterogeneity was quantified with I 2. Both sensitivity and subgroup analyses were used to identify the sources of heterogeneity. Publication bias was assessed with funnel plots. We used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to rate the evidence quality. Outcomes included assessments using the Activities of Daily Living (ADL), Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Hasegawa Dementia Scale (HDS), Barthel Index (BI), Functional Activity Questionnaire (FAQ), and adverse events. RESULTS: In this study, a total of 2019 patients in 23 RCTs were included. EGb appeared to be more effective than control conditions as assessed by the results of cognitive function evaluation, including MMSE (MDMMSE,EGb vs.blank = 3.04, 95% CI: 0.10-5.98; MDMMSE,EGb vs.drugs for VCI = 2.70, 95% CI: 1.39-4.01; MDMMSE,EGb+drugs for VCI vs.blank = 5.90, 95% CI: 4.21-7.59; and MDMMSE,EGb+drugs for VCI vs.drugs for VCI = 3.14, 95% CI: 2.14-4.15), MoCA (MDMoCA,EGb vs.blank = 5.30, 95% CI: 2.15-8.46; MDMoCA,EGb+drugs for VCI vs.blank = 2.66, 95% CI: 1.82-3.50; and MDMoCA,EGb+drugs for VCI vs.drugs for VCI = 2.56, 95% CI: 1.85-3.27), HDS (MDHDS,EGb vs.blank = 6.50; 95% CI: 4.86-8.14; MDHDS,EGb+drugs for VCI vs.drugs for VCI = 3.60, 95% CI: 2.50-4.70), ADL (MDADL,EGb vs.blank = 7.20, 95% CI: 3.28-11.12; MDADL,EGb+drugs for VCI vs.blank = 10.00, 95% CI: 7.51-12.49; and MDADL,EGb+drugs for VCI vs.drugs for VCI = 9.20, 95% CI: 7.26-11.14), BI (MDBI,EGb+drugs for VCI vs.drugs for VCI = 5.71, 95% CI: 2.99-8.43; MDFAQ,EGb vs.drugs for VCI = -1.43, 95% CI: -2.78 to 0.08), and FAQ (MDFAQ,EGb+drugs for VCI vs.drugs for VCI = -2.17, 95% CI: -4.13 to 0.21). Evidence of certainty ranged from medium certainty to very low certainty. CONCLUSION: This meta-analysis showed that EGb may be an effective and safe treatment in improving MMSE, MOCA, ADL, and BI for VCI patients within three months of diagnosis. However, given the quality of the included RCTs, more preregistered trials are needed that explicitly examine the efficacy of EGb. This systematic review has been registered on PROSPERO, with the registration number CRD42021232967.

Design and Mechanical Properties Verification of Gradient Voronoi Scaffold for Bone Tissue Engineering.

In order to obtain scaffold that can meet the therapeutic effect, researchers have carried out research on irregular porous structures. However, there are deficiencies in the design method of accurately controlling the apparent elastic modulus of the structure at present. Natural bone has a gradient porous structure. However, there are few studies on the mechanical property advantages of gradient bionic bone scaffold. In this paper, an improved method based on Voronoi-tessellation is proposed. The method can get controllable gradient scaffolds to fit the modulus of natural bone, and accurately control the apparent elastic modulus of porous structure, which is conducive to improving the stress shielding. To verify the designed structure can be fabricated by additive manufacturing, several designed models are obtained by SLM and EBM. Through finite element analysis (FEA), it is verified that the irregular porous structure based on Voronoi-tessellation is more stable than the traditional regular porous structure of the same structure volume, the same pore number and the same material. Furthermore, it is verified that the gradient irregular structure has a better stability than the non-gradient structure. An experiment is conducted successfully to verify the stability performance got by FEA. In addition, a dynamic impact FEA is also performed to simulate impact resistance. The result shows that the impact resistance of the regular porous structure, the irregular porous structure and the gradient irregular porous structure becomes better in turn. The mechanical property verification provides a theoretical basis for the structural design of gradient irregular porous bone tissue engineering scaffolds.

Dynamic evaluation and spatiotemporal evolution of China's industrial water use efficiency considering undesirable output.

Water is a strategic and basic resource for industrial development. The efficient use of water resources is of great significance for the sustainable development of the economy and society. Dynamic SBM model could overcome the shortcomings of static models and reflect inter-temporal efficiency levels. The kernel density curve is used to fit the distribution pattern of industrial water use efficiency and describe its dynamic evolution. Empirical results show that from 2013 to 2017, under the meta-frontier, the industrial water use efficiency values of Beijing, Tianjin, Shandong, Inner Mongolia, and Shaanxi are all 1, and industrial water use efficiency is high, while the industrial water use efficiency values of Sichuan, Guizhou, Anhui, and other provinces are below 0.3, reflecting the low industrial water use efficiency. From 2013 to 2015, China's industrial water use efficiency generally shows a downward trend but begins to rise in the next 2 years. The kernel density curve generally exhibits a bimodal distribution trend and evolves from a "spike shape" to a "broad peak shape".