Protection of rat islet viability following heme oxygenase-1 gene transfection via adenoviral vector in vitro

Objective: To investigate the effect of Heme oxygenase-1 (HO-1) gene transfection on the viability of cultured rat islets, and to explore the potential value of HO-1 gene in islet transplantation. Methods:Recombinant adenovirus vector containing human HO-1 gene(Ad-HO-1 ) or enhanced green fluorescent protein gene(Ad-EGFP) was generated by using AdEasy system respectively.The rat islets were transfected with Ad-HO-1, Ad-EGFP or blank vector and then cultured for 7 days. Transfection was confirmed by expression of EGFP and human HO-1 protein detected by fluorescence photographs and western blot, respectively. The insulin release upon different concentration of glucose stimulation was detected using insulin radioimmunoassay kit, and stimulation index (SI) was calculated. Glucose-stimulated insulin release was usedto assess islet viability. Results:Adenovirus vector successfully transferred HO-1 gene to rat islet cells in vitro, and the insulin release upon high level of glucose stimulation and stimulation index(SI) of Ad-HO-1-infected islets were significantly higher than those of Ad-EGFP-infected islets and control islets(P ＜ 0.05).Conclusion: Adenovirus-mediated HO-1 gene transfection is a feasible strategy to confer cytoprotection and therefore protect the viability of cultured rat islets.     

Predictors of post coronary artery bypass grafting atrial fibrillation

Objective: To investigate the incidence and relative risk factors of post coronary artery bypass grafting(post-CABG) atrial fibrillation (AF). Methods: 312 patients with CABG were reviewed and divided into an AF group and a non-AF group. Statistical analysis was used to compare the data between the two groups and screen for risk factors of post-CABG AF. Results: 103/312(33.01%) patients developed post-CABG AF. Univariate analysis showed that patients in AF group compared with those in non-AF group were more likely to have advanced age (≥ 70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement ( ≥40 mm), a history of AF, prolonged p-wave duration ( ≥ 120 ms) and increased number of grafts (≥3). Multivariate logistic regression analysis showed that advanced age (≥70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement (≥40 mm) and a history of AF were highly related to post-CABG AF. Conclusion: The incidence of AF in patients following CABG was 33.01% in this study. Advanced age, early postoperative withdrawal of β-blockers,hypertension, left atrial enlargement and a history of AF were independent risk factors of post-CABG AF.     

改良双钢板法对比微创内固定系统治疗复杂胫骨平台骨折的疗效综合评价

目的对改良双钢板法与微创内固定系统（uss）治疗复杂胫骨平台骨折的疗效进行对比分析。方法168例复杂胫骨平台骨折患者按照治疗方法不同分为改良双钢板组（89例,采用改良双钢板法治疗）和LISS组（79例,采用LISS法治疗）,对两种治疗方法的优缺点及疗效进行比较分析。结果改良双钢板组患者治疗效果优良率（89．9％,80／89）略大于LISS组患者的优良率（86．1％,68／79）,两组比较差异无统计学意义（P〉0．05）。两组患者均未出现深部感染及严重的神经损害、静脉血栓等并发症。改良双钢板组手术时间（89．2±13．6）min,术中出血量（188．4±45．6）ml,住院时间（16．5±1．8）d,愈合时间（13．3±2．1）个月,LISS组手术时间（74．3±12．5）min,术中出血量（236．5±65．5）ml,住院时间（16．7±2．1）d,愈合时间（11．4±1．5）个月,两组比较差异无统计学意义（P〉0．05）。结论对于复杂胫骨平台骨折患者的治疗,LISS与改良双钢板法的治疗效果无显著差异。     

骨桥蛋白在肝包虫动物模型外囊壁中的表达

目的:观察动物模型肝包虫囊壁情况,研究骨桥蛋白(Osteopontin,OPN)在小鼠肝细粒棘球蚴外囊壁中的分布特征及表达相关因素,并探讨其意义.方法:肝包虫动物模型的制作、HE染色观察、免疫组化观察53例小鼠肝细粒棘球蚴外囊壁中OPN及巨噬细胞的表达与分布.结果:HE染色外囊的着色明显较周围巨噬细胞带深,不存在渐变的过程;83%肝细粒棘球蚴外囊壁中有不同程度OPN表达,且集中分布于肝包虫纤维囊壁(外囊),与外侧巨噬细胞带比较有显著差异(P＜0.01).结论:在动物模型上证明了外囊与肝实质间存在可分离间隙,OPN主要分布在肝细粒棘球蚴外囊,并在其形成过程中起重要作用.     

原发性肾小球肾炎患者肾小管间质中整合素连接激酶的表达及意义

目的:检测不同间质纤维化程度的原发性肾小球肾炎患者肾组织中整合素连接激酶(ILK)的表达,观察ILK与肾间质纤维化程度之间的关系,探讨ILK在肾间质纤维化中可能的作用.方法:选取原发性肾小球肾炎患者肾活检标本88例,根据肾间质纤维化程度分为四组,采用免疫组化方法,检测各组标本ILK的表达,并将ILK的表达与间质纤维化程度和患者血尿β2微球蛋白水平进行相关分析.结果:ILK主要表达于病变肾小管上皮细胞,并且随间质病变的加重,表达量增加,范围增大.肾小管间质中ILK表达量与肾间质纤维化病变程度和患者血尿β2微球蛋白均呈正相关关系.结论:ILK可能参与了肾间质纤维化的形成.     

Acoustic Metamaterials for Low-Frequency Noise Reduction Based on Parallel Connection of Multiple Spiral Chambers

Acoustic metamaterials based on Helmholtz resonance have perfect sound absorption characteristics with the subwavelength size, but the absorption bandwidth is narrow, which limits the practical applications for noise control with broadband. On the basis of the Fabry–Perot resonance principle, a novel sound absorber of the acoustic metamaterial by parallel connection of the multiple spiral chambers (abbreviated as MSC-AM) is proposed and investigated in this research. Through the theoretical modeling, finite element simulation, sample preparation and experimental validation, the effectiveness and practicability of the MSC-AM are verified. Actual sound absorption coefficients of the MSC-AM in the frequency range of 360–680 Hz (with the bandwidth Δf₁ = 320 Hz) are larger than 0.8, which exhibit the extraordinarily low-frequency sound absorption performance. Moreover, actual sound absorption coefficients are above 0.5 in the 350–1600 Hz range (with a bandwidth Δf₂ = 1250 Hz), which achieve broadband sound absorption in the low–middle frequency range. According to various actual demands, the structural parameters can be adjusted flexibly to realize the customization of sound absorption bandwidth, which provides a novel way to design and improve acoustic metamaterials to reduce the noise with various frequency bands and has promising prospects of application in low-frequency sound absorption.     

Mechanical Modeling of Tube Bending Considering Elastoplastic Evolution of Tube Cross-Section

Aluminum alloy tubes are widely used in various industries because of their excellent performance. Up to now, when the tube is bent, the elastoplastic deformation evolution mechanism of the cross-section has not been clear, and no direct analytical proof has been found. In this paper, based on the bilinear material model assumption, a new mechanical model of tube plane bending deformation is constructed. The analytical model can describe in detail the evolution mechanism of elastic–plastic deformation on the cross-section of the tube after bending deformation, the position of the elastic–plastic boundary, the position of the radius of the strain neutral layer, and the relationship between the bending moment over the section and the bending radius. According to this model, the deformation law of the tube cross-section during bending is elucidated. The results are as follows: (1) the deformation evolution of the cross-section of the bending deformed tube calculated by the analytical model is in good agreement with the finite element model (FEM) of pure bending. (2) By comparing the results of the analytical model with FEM results, and the processing test of the self-designed four-axis free bending forming tube bender, the bending moments are in good agreement. (3) Compared with the bending moments calculated by several other analytical models of tube bending, this model has a relatively small deviation value.     

Application of Iron Tailings-Based Composite Supplementary Cementitious Materials (SCMs) in Green Concrete

How to treat the iron tailings of mining solid waste with high value is an urgent problem on a global scale. In recent years, the application of iron tailings in the building materials industry has attracted the attention of many scholars. The conversion of iron tailings into green building materials helps achieve carbon neutrality and high-value utilization of solid waste, and promotes sustainable development. Although iron tailings have been extensively studied as supplementary cementitious materials, the performance of concrete is not ideal due to its low activity. In this study, the hybrid supplementary cementitious materials system was prepared by iron tailings, phosphorus slag, and steel slag, and the effects of supplementary cementitious materials type, iron tailings content, iron tailings grinding time, and supplementary cementitious materials content on concrete performance were studied. The compressive properties, iron tailings properties, pore structure, interfacial transition zone, and element distribution of hydration products of concrete were tested by compressive strength tests, X-ray Diffractometer (XRD), X-ray Photoelectron Spectroscopy (XPS), Mercury Intrusion Porosimetry (MIP), Backscattering Electron Tests (BSE), and Energy Dispersive Spectrometer (EDS). The results show that further grinding improves the iron tailings activity. There is a synergistic mechanism between steel slag and phosphorus slag in the composite supplementary cementitious materials, which overcomes the low activity defect of iron tailings and produces concrete with a compressive strength exceeding 40 MPa. The composite supplementary cementitious materials can optimize the interfacial transition zone of the concrete interface and reduce the calcium–silicon ratio of the hydration products. However, it will deteriorate the pore structure of the concrete matrix, cause part of the concrete matrix to be damaged and lead to a loss of compressive strength, and the loss is acceptable. This work broadens the methods of comprehensive utilization of iron tailings and also provides a reference for a more detailed understanding of the properties of iron tailings-based concrete.     

Local Electrochemical Corrosion Properties of a Nano-SiO2/MAO Composite Coating on an AM60B-Mg Alloy

In order to improve the corrosion resistance of the automotive AM60B-Mg alloy, a nano-SiO₂/MAO composite coating was prepared on the surface of the alloy. The electrochemical properties were studied in an 80 °C corrosion environment using potentiodynamic polarization tests. Local Electrochemical Impedance Spectroscopy (LEIS) was used to study the corrosion mechanisms of coating defect zone. The microstructure and phase of the samples were observed by confocal laser microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Macroscopic electrochemical test results showed that the impedance of the nano-SiO₂/MAO coating was much higher than that of the MAO coating, by about 433 times. Local electrochemical test results showed that the minimum impedance of the nano-SiO₂/MAO coating was 1–2 orders of magnitude higher than the maximum impedance of the MAO coating. The defective SiO₂/MAO coating still had high corrosion resistance compared to the defective MAO coating. A physical model of local corrosion mechanisms was proposed.