A Multibody Dynamics Model of a Motorcycle with a Multi-link Front Suspension

The development of motorcycles has been around for over a century. Nowadays, it has become one of the most popular means of transportation in the world. It is well known that the telescopic fork is the most widely used front suspension for motorcycles, because the first motorcycle was a bicycle with a small engine attached to the frame. However, there are a number of shortcomings inherent in this design. Therefore, a novel multi-link suspension has been designed for the front assembly of the motorcycle in this research. In order to compare the performance between telescopic fork and multi-link front suspension motorcycles, linear and nonlinear models were built and simulated under a variety of different conditions. Furthermore, an appropriate method of comparison between conventional and multi-link models was developed, and the assessment standard of performance for conventional and multi-link models was explored in this research

Influence of composite elastic modulus and lateral load pattern on deflection of anti-slide pile head

This paper develops a new method to directly determine the composite elastic modulus of the reinforced con­crete cantilever pile rather than adopt theoretical or empirical approaches. On the basis of the theory of material mecha­nism, the load-deflection equation was deduced to create the relationship between the elastic modulus and the ratio of load-deflection. The numerical modelling tests based on ANSYS separation modelling technology were carried out to determine the composite elastic modulus under different reinforcement ratio, concrete strength grade and distribution pat­tern of driving force. The results can be used to create the quantitative relationship between the composite elastic modulus and reinforcement ratio as well as concrete strength grade. Comparison amongst various lateral load pattern were made to show that the deflection of pile head is obviously affected by the lateral load pattern, and the corresponding equations of the deflection of the pile head under different lateral load pattern were proposed, which can reflect the ranking of the great influence on the deflection of the pile head, rectangular, trapezoidal and triangular lateral load pattern in order. First published online: 24 Aug 201

Factors influencing early recurrence of atrial fibrillation among elderly patients following radiofrequency catheter ablation and the impact of different antiarrhythmic regimens

BackgroundPatients with atrial fibrillation (AF) who undergo radiofrequency catheter ablation (RFCA) necessitate the administration of antiarrhythmic drugs to prevent early recurrence. The clinical outcomes among these patients may be influenced by varying antiarrhythmic regimens.ObjectivesTo identify the risk factors associated with early recurrence and compare the clinical outcomes among different antiarrhythmic regimens in elderly patients with AF following radiofrequency catheter ablation (RFCA) during a 3-month period.MethodsA retrospective observational study encompassed 420 elderly patients with AF following RFCA. Baseline data were collected during the initial postoperative visit and clinical outcomes were carefully monitored over a 3-month follow-up period. Logistic regression and Cox-proportional hazard regression analyses were performed to investigate the relationship between various antiarrhythmic regimens and the clinical outcomes.ResultsMultivariate logistic regression analysis revealed that age (p = 0.001), left atrial diameter (p < 0.001), left ventricular diameter (p = 0.015), reactive hyperemia index (RHI) (p < 0.001), antiarrhythmic drug (p < 0.001) and hs-cTnI (p = 0.017) were independent risk factors of early recurrence. Furthermore, in cox survival regression analysis model, survival rate of early recurrence in the amiodarone group was higher than in the propafenone group (HR 2.30, 95%CI 1.17–4.53, p = 0.016) and in the sotalol group (HR 3.60, 95%CI 2.17–5.95, p < 0.001). Compared to the amiodarone group, the incidence of liver dysfunction was lower in the dronedarone group (p = 0.046) and the propafenone group (p = 0.021). The incidence of bradyarrhythmia (p = 0.003), QT interval prolongation (p = 0.035) and atrioventricular transmission block (p = 0.021) were higher in the sotalol group than in the amiodarone group.ConclusionRHI was identified as an independent risk factor for early recurrence among elderly AF patients after RFCA. Compared to amiodarone, propafenone and sotalol exhibited an elevated risk of early recurrence. Although there was no significant difference in early recurrence between amiodarone and dronedarone, dronedarone emerged as the preferred option due to its lower frequency of adverse drug reactions than amiodarone

Structural insights into the Cdt1-mediated MCM2–7 chromatin loading

Initiation of DNA replication in eukaryotes is exquisitely regulated to ensure that DNA replication occurs exactly once in each cell division. A conserved and essential step for the initiation of eukaryotic DNA replication is the loading of the mini-chromosome maintenance 2–7 (MCM2–7) helicase onto chromatin at replication origins by Cdt1. To elucidate the molecular mechanism of this event, we determined the structure of the human Cdt1-Mcm6 binding domains, the Cdt1(410–440)/MCM6(708–821) complex by NMR. Our structural and site-directed mutagenesis studies showed that charge complementarity is a key determinant for the specific interaction between Cdt1 and Mcm2–7. When this interaction was interrupted by alanine substitutions of the conserved interacting residues, the corresponding yeast Cdt1 and Mcm6 mutants were defective in DNA replication and the chromatin loading of Mcm2, resulting in cell death. Having shown that Cdt1 and Mcm6 interact through their C-termini, and knowing that Cdt1 is tethered to Orc6 during the loading of MCM2–7, our results suggest that the MCM2–7 hexamer is loaded with its C terminal end facing the ORC complex. These results provide a structural basis for the Cdt1-mediated MCM2–7 chromatin loading

The first clinical data of the SAPIEN 3 aortic valve in the treatment of aortic stenosis in China

BackgroundData on outcomes following transcatheter aortic valve replacement with SAPIEN 3 in China is limited as it was approved by the National Medical Products since 2020. The present study was designed to collect clinical data on the SAPIEN 3 aortic valve in Chinese patients with bicuspid aortic valve and tricuspid aortic valve stenosis.MethodsWe analyzed the patient characteristics, procedural features and procedural outcomes of the first 438 patients (223 for bicuspid aortic valve and 215 tricuspid aortic valve) from 21 provinces in 74 sites treated with the SAPIEN 3 valve system for transcatheter aortic valve replacement between September 2020 and May 2022.ResultsProcedural mortality was 0.7%. 5 cases during the operation were converted to surgery. Among 438 cases, permanent pacemaker implantation was performed in a total of 12 cases (2.7%). The patient had severe leaflet calcification of the aortic valve, with moderate and severe calcification reaching 39.7% and 35.2% respectively. The size of the implanted valves was predominantly 26 mm and 23 mm, reaching 42.5% and 39.5% respectively. The incidence of moderate or severe perivalvular leak in the postoperative period was 0.5%, with a predominance of 90/10 and 80/20 valve deployment height. There was a significant difference in the deployment height of the valve between bicuspid aortic valve and tricuspid aortic valve, with the bicuspid aortic valve having a more deployment height of 90/10. Annulus size in bicuspid aortic valve group was significantly larger than tricuspid aortic valve group. Valve sizing for oversized, within size, and undersized were different between bicuspid aortic valve and tricuspid aortic valve.ConclusionsProcedural success rates were high, with similar and good results for bicuspid aortic valve and tricuspid aortic valve, low perivalvular leak for both valve types, and low permanent pacemaker implantation rates for both valve types. Annulus size, valve sizing and coronary artery height were significantly different in the BAV and TAV group

The 2011 Survey on Hypertensive Disorders of Pregnancy (HDP) in China:Prevalence, Risk Factors, Complications, Pregnancy and Perinatal Outcomes

Hypertensive disorders of pregnancy (HDP) are a group of medical complications in pregnancy and also a risk factor for severe pregnancy outcomes, but it lacks a large-scale epidemiological investigation in recent years. This survey represents a multicenter cross-sectional retrospective study to estimate the prevalence and analyze the risk factors for HDP among the pregnant women who had referred for delivery between January 1st 2011 and December 31st 2011 in China Mainland. A total of 112,386 pregnant women were investigated from 38 secondary and tertiary specialized or general hospitals randomly selected across the country, of which 5,869 had HDP, accounting for 5.22% of all pregnancies. There were significant differences in the prevalence of HDP between geographical regions, in which the North China showed the highest (7.44%) and Central China showed the lowest (1.23%). Of six subtypes of HDP, severe preeclampsia accounted for 39.96%, gestational hypertension for 31.40%, mild preeclampsia for 15.13%, chronic hypertension in pregnancy for 6.00%, preeclampsia superimposed on chronic hypertension for 3.68% and eclampsia for 0.89%. A number of risk factors for HDP were identified, including twin pregnancy, age of >35 years, overweight and obesity, primipara, history of hypertension as well as family history of hypertension and diabetes. The prevalence of pre-term birth, placental abruption and postpartum hemorrhage were significantly higher in women with HDP than those without HDP. The possible risk factors confirmed in this study may be useful for the development of early diagnosis and appropriate treatment of HDP

Joint analysis of three genome-wide association studies of esophageal squamous cell carcinoma in Chinese populations

We conducted a joint (pooled) analysis of three genome-wide association studies (GWAS) 1-3 of esophageal squamous cell carcinoma (ESCC) in ethnic Chinese (5,337 ESCC cases and 5,787 controls) with 9,654 ESCC cases and 10,058 controls for follow-up. In a logistic regression model adjusted for age, sex, study, and two eigenvectors, two new loci achieved genome-wide significance, marked by rs7447927 at 5q31.2 (per-allele odds ratio (OR) = 0.85, 95% CI 0.82-0.88; P=7.72x10−20) and rs1642764 at 17p13.1 (per-allele OR= 0.88, 95% CI 0.85-0.91; P=3.10x10−13). rs7447927 is a synonymous single nucleotide polymorphism (SNP) in TMEM173 and rs1642764 is an intronic SNP in ATP1B2, near TP53. Furthermore, a locus in the HLA class II region at 6p21.32 (rs35597309) achieved genome-wide significance in the two populations at highest risk for ESSC (OR=1.33, 95% CI 1.22-1.46; P=1.99x10−10). Our joint analysis identified new ESCC susceptibility loci overall as well as a new locus unique to the ESCC high risk Taihang Mountain region