Effects of storage and reperfusion oxygen content on substrate metabolism in the isolated rat lung

BACKGROUND: Lung transplantation requires a period of storage and ischemia; we examined the largely unknown effects of that period on intermediary metabolism. METHODS: Two groups of isolated rat lung blocks (n = 16 each) were flushed with Euro-Collins solution and harvested. The lung blocks were immediately ventilated and either perfused for 30 minutes with an erythrocyte-based solution containing carbon 13 labeled substrates (group 1) or stored for 6 hours at 1 degree C and then reperfused (group 2). Half of each group was reperfused at a physiologic Po2 the other half at high Po2. Analysis of carbon 13 isotopomers was performed to determine substrate utilization through aerobic pathways in lung tissue. RESULTS: Lungs from both groups oxidized all major substrates. The contribution of fatty acids to acetylcoenzyme acid oxidized in the citric acid cycle was significantly higher in group 2 than in group 1 (31.3% +/- 2.2% versus 22.0% +/- 2.1%, p < 0.05). Perfusate Po2 did not affect substrate preference. Gas exchange was worse in stored lungs. CONCLUSIONS: After a period of hypothermic ischemia and storage, substrate preference in lung tissue exhibits a switch towards fatty acids. As fatty acid oxidation occurring after ischemia is deleterious in other organs, strategies to inhibit this process in stored lungs may warrant further investigation.     

MVD及VEGF在颅咽管瘤中的表达及其与预后的关系

背景与目的：颅叫管瘤为难治性肿瘤，其预后不良，复发机制尚不清楚。本研究检测颅Ⅱ阏管瘤组织中微血管密度（microvascular density，MVD）及血管内皮生长因子vascular endothelial growth factor，VEGF表达．分析其与肿瘤预后等生物学行为的关系。方法：采取前瞻性队列研究方案，经纳入、排除标准筛选卅颅咽管釉质上皮型肿瘤32例、鳞形乳头瘤型肿瘤31例，平均随访843个月，收集原发及复发患者的肿瘤组织标本，应用单克隆抗体CD34、VEGF抗体检测肿瘤组织MVD及VEGF蛋白表达，计算机辅助成像系统对其作出定量分析，分析其与肿瘤复发等生物学行为的关系。结果：VEGF蛋白、MVD计数在颅咽管瘤队列复发组、非复发组间不具有显著性差异（P〉0．05），而在颅咽管瘤不同病理类型间差异则具有显著性（P〈0．05）。结论：VEGF蛋白、MVD计数与肿瘤复发无关，不能预测颅咽管瘤复发的危险性，但可为了解肿瘤的同有侵袭性行为提供参考。     

Medial cortex strain distribution during noncemented total hip arthroplasty

Intraoperative proximal femur fractures are a significant concern during noncemented total hip arthroplasty. The current study was performed to investigate the hypothesis that broaching the femur and inserting the stem without using mallet applied impact loads will reduce the risk of intraoperative fracture. Rosette strain gauges were applied to the medial and anteromedial cortex of six human anatomic specimen femurs to compare the strain distribution for broaching and stem insertion. Eight additional femurs were used to compare the strain distribution for stem insertion using impact loading and constant rate stem insertion. For the impact loading stem insertions, the soft tissues surrounding the femur were modeled. Constant rate stem insertions were performed using a mechanical testing machine. The largest strains measured at the medial and anteromedial sites primarily were aligned with the femur hoop axis. The largest strain magnitude, orientation, and sign (tensile or compressive) varied widely among femurs. The stem insertion strains were significantly larger than the broaching strains (two-way analysis of variance with replication). The impact stem insertion strains were not significantly different from the constant rate stem insertion strains. The results indicate that the femur geometry and material properties have a greater influence on the strain distribution than does the implantation technique.     

基于金磁微粒标记技术的可目视化蛋白质芯片检测方法的建立

目的：应用金磁微粒标记蛋白质技术,建立可目视化蛋白质芯片检测体系,比较金磁微粒和胶体金标记蛋白质技术应用于蛋白质芯片检测效果的优劣。方法：将人IgG点制于环氧基修饰的玻片上,分别与金磁微粒和胶体金标记的羊抗人IgG温育,银染显色,肉眼观察并用普通扫描仪记录结果。结果：基于金磁微粒的蛋白质芯片人IgG最佳点样浓度为0．2mg／ml,37℃温育2h,银染10～15min,检测结果信噪比高;基于胶体金的蛋白质芯片人IgG最佳点样浓度为0．1mg／ml,37℃温育1h,银染15～20min．检测结果信噪比高。结论：金磁微粒标记蛋白质技术应用于蛋白质芯片的检测,具有和胶体金一致的可目视化检测效果。且其标记技术简单,标记的蛋白质可定量。     

皮肤对紫外线红斑反应敏感度的季节因素研究

目的：比较春夏秋冬4个季节不同部位皮肤对紫外线红斑反应的敏感性,了解皮肤紫外线红斑反应敏感度的影响因素。方法：春夏秋冬4个季节分别在40名受试者的前臂伸侧（曝光部位）和上臂屈侧（非曝光部位）使用中波紫外线（UVB）（181．44、140．40、88．56、56．16mJ）及长波紫外线（UVA）＋UVB03．49J／364．80mJ,9．91J／273．60mJ,6．62J／190．00mJ,4．45J／125．40mJ）西各4个剂量进行照射。照射前及照射后10min、24h、48h、第7天、第14天进行临床评分和使用Mexameter（皮肤黑素和血红素测定仪）进行检测,计算皮肤红斑指数改变率（EIR）。结果：①非曝光部位红斑反应强度在春季显著大于其他季节（P〈0．05）,与非曝光部位的四季皮肤基础色素情况完全一致,且具有相关性（P〈0．05）。②春季和其他3个季节间曝光部位红斑反应强度差异均有统计学意义（P〈0．05）。结论：四季中春季对紫外线红斑反应的敏感性最高。表皮中黑素含量会影响皮肤对紫外线的敏感性。     

紫茎泽兰羟基泽兰酮在大鼠体内毒代动力学与组织分布

目的 探讨紫茎泽兰羟基泽兰酮(Euptox A)在大鼠体内的毒代动力学和组织分布.方法 将15只Wistar大鼠随机分为3组,每组5只;分别静脉给予Euptox A 25、50和100mg·kg-1后,于不同时间点采集血样;另18只大鼠随机分为3组,每组6只;静脉给予Euptox A 50mg·kg-1后,分别于10、...     

Evaluation of physician experience in achieving non-perfused volume ratio of high-intensity focused ultrasound ablation for uterine fibroids: a multicentre study

ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.     

The Uncertainty Propagation for Carbon Atomic Interactions in Graphene under Resonant Vibration Based on Stochastic Finite Element Model

Graphene is one of the most promising two-dimensional nanomaterials with broad applications in many fields. However, the variations and fluctuations in the material and geometrical properties are challenging issues that require more concern. In order to quantify uncertainty and analyze the impacts of uncertainty, a stochastic finite element model (SFEM) is proposed to propagate uncertainty for carbon atomic interactions under resonant vibration. Compared with the conventional truss or beam finite element models, both carbon atoms and carbon covalent bonds are considered by introducing plane elements. In addition, the determined values of the material and geometrical parameters are expanded into the related interval ranges with uniform probability density distributions. Based on the SFEM, the uncertainty propagation is performed by the Monte Carlo stochastic sampling process, and the resonant frequencies of graphene are provided by finite element computation. Furthermore, the correlation coefficients of characteristic parameters are computed based on the database of SFEM. The vibration modes of graphene with the extreme geometrical values are also provided and analyzed. According to the computed results, the minimum and maximum values of the first resonant frequency are 0.2131 and 16.894 THz, respectively, and the variance is 2.5899 THz. The proposed SFEM is an effective method to propagate uncertainty and analyze the impacts of uncertainty in the carbon atomic interactions of graphene. The work in this paper provides an important supplement to the atomic interaction modeling in nanomaterials.     

Magnetic Properties and Washability of Roasted Suspended Siderite Ores

Steel is one of the most important industrial materials, which mainly comes from the smelting of iron ore. In view of the huge steel consumption every year, the exploitation of vast reserves of siderite ores is significant for improving the self-sufficiency rate of iron ore resources and ensuring the strategic security of the iron and steel industries. This paper investigated the influence of temperature, time, and other parameters on the magnetic properties of roasted siderite ores using the method of suspended roasting and analyzed the washability of roasted ores under weak-magnetic-field conditions using the magnetic separation tube experiment. The findings of the study explained the iron phase transformation process, i.e., FeCO₃ was transformed into Fe₃O₄ by suspension magnetization roasting. Furthermore, the saturation magnetization of the roasted ore increased in due time at a constant temperature range of 550–750 °C and a roasting time of less than 5 s. It also increased with increasing temperature and constant time. The roasted ore achieved the best magnetic characteristics after roasting at 750 °C for 5 s. After low-intensity magnetic separation, the iron grade of the concentrate changed to 55.12%, with a recovery rate of 90.34%. The study results provide a reference for the development and application of siderite suspension magnetization roasting technology.     

Preparation and study of the flame retardant properties of C60/PMMA microspheres

In this paper, highly flame retardant C₆₀/PMMA composites were prepared using an in situ polymerization method by introducing fullerene (C₆₀) into polymethyl methacrylate (PMMA) to improve its combustion characteristics. The apparent morphologies of PMMA and C₆₀/PMMA microspheres were observed by scanning electron microscopy (SEM), and the structure was characterized by infrared spectroscopy (FT-IR). The thermal stability and flame retardancy were characterized using a synchronous thermal analyzer, a cone calorimeter and an oxygen index tester. The results show that the maximum initial decomposition temperature of C₆₀/PMMA-2 (prepared using C₆₀ with a concentration of 2 mg mL⁻¹) is 234.89 °C, which is about 59.89 °C higher than that of PMMA, and the thermal stability is the best. The limiting oxygen index of the C₆₀/PMMA-2 composite is 21.8, which is 28.2% higher than that of pure PMMA. In addition, the peak heat release rate (PHRR) of C₆₀/PMMA is reduced by 630.4 kW m⁻² when compared with pure PMMA, which means that the flame retardant property is improved. Meanwhile, the mechanical properties of the PMMA are also improved by adding C₆₀.

In this paper, highly flame retardant C₆₀/PMMA composites were prepared using an in situ polymerization method by introducing fullerene (C₆₀) into polymethyl methacrylate (PMMA) to improve its combustion characteristics.