圣脑康丸防治急性高原反应的现场观察

目的研究圣脑康丸对急性高原反应的即时防治效果。方法随机选择54名空运至拉萨(海拔3 700 m)的新兵,分为对照组(n=18)、红景天组(n=18)、圣脑康组(n=18),在进入高原前3 d开始分别服用空白胶囊、红景天胶囊、圣脑康丸,连续服用至进入高原的第7天止,定期测定血氧饱和度(SaO2)和心率(HR),以军用卫生标准GJB1098-91《急性高原反应的诊断和处理原则》随访记录受试者急性高原反应症状并评分。结果圣脑康组预防急性高原反应的效果明显优于对照组,圣脑康组急性高原反应评分以及进入高原第1,3,5天时的血氧饱和度(SaO2)和心率(HR)均显著优于对照组(P<0.05或0.01)。结论圣脑康丸能减轻缺氧症状的严重程度,降低急性高原反应的发生率,具有防治急性高原反应的功效。     

On the Morphological Deviation in Additive Manufacturing of Porous Ti6Al4V Scaffold: A Design Consideration

Additively manufactured Ti scaffolds have been used for bone replacement and orthopaedic applications. In these applications, both morphological and mechanical properties are important for their in vivo performance. Additively manufactured Ti6Al4V triply periodic minimal surface (TPMS) scaffolds with diamond and gyroid structures are known to have high stiffness and high osseointegration properties, respectively. However, morphological deviations between the as-designed and as-built types of these scaffolds have not been studied before. In this study, the morphological and mechanical properties of diamond and gyroid scaffolds at macro and microscales were examined. The results demonstrated that the mean printed strut thickness was greater than the designed target value. For diamond scaffolds, the deviation increased from 7.5 μm (2.5% excess) for vertical struts to 105.4 μm (35.1% excess) for horizontal struts. For the gyroid design, the corresponding deviations were larger, ranging from 12.6 μm (4.2% excess) to 198.6 μm (66.2% excess). The mean printed pore size was less than the designed target value. For diamonds, the deviation of the mean pore size from the designed value increased from 33.1 μm (−3.0% excess) for vertical struts to 92.8 μm (−8.4% excess) for horizontal struts. The corresponding deviation for gyroids was larger, ranging from 23.8 μm (−3.0% excess) to 168.7 μm (−21.1% excess). Compressive Young’s modulus of the bulk sample, gyroid and diamond scaffolds was calculated to be 35.8 GPa, 6.81 GPa and 7.59 GPa, respectively, via the global compression method. The corresponding yield strength of the samples was measured to be 1012, 108 and 134 MPa. Average microhardness and Young’s modulus from α and β phases of Ti6Al4V from scaffold struts were calculated to be 4.1 GPa and 131 GPa, respectively. The extracted morphology and mechanical properties in this study could help understand the deviation between the as-design and as-built matrices, which could help develop a design compensation strategy before the fabrication of the scaffolds.     

Ancillary ligand effects on α-olefin polymerization catalyzed by zirconium metallocene: a computational study

The polymerization of α-olefins catalyzed by zirconium metallocene catalyst was systematically studied through experiments and density functional theory (DFT) calculations. Having achieved an agreement between theory and experiment, it was found that the effect of the catalyst ligand on the C C insertion reaction was significantly greater than that on the β-H elimination reaction. Therefore, the molecular weight of polymers can be increased by improving the activity of the C C insertion. In addition, in comparison with propylene, the chain length of α-olefins can directly affect the stereotacticity of polymerization products, owing to steric hindrance between the polymer chain and monomer.

The polymerization of α-olefins catalyzed by zirconium metallocene catalyst was systematically studied through experiments and density functional theory (DFT) calculations.     

Transcatheter closure of inferior sinus venosus defect using a patent ductus arteriosus occluder following simulation with a 3D-printed model

BackgroundTranscatheter closure of inferior sinus venosus defect (ISVD) is still contraindication. To explore whether transcatheter closure with patent ductus arteriosus (PDA) occluders is possible for ISVD.MethodsFrom June 2014 to March 2021, 12 patients were recruited diagnosed as <25 mm ISVD. The three-dimensional printing (3DP) heart model was produced based on multi-slice computed tomography (MSCT) scans. Preoperative closure simulation was planned on the personalized 3D model for each patient. Follow-up including electrocardiography (ECG), transthoracic echocardiography (TTE), and X-ray was traced.Results3DP models of 12 patients were successfully printed. Twelve patients had been diagnosed with <25 mm ISVD and 4 of them had another secundum atrial septal defect (ASD). All patients were produced interventional therapy successfully. PDA occluder was implanted to closed ISVD, and ASD was closed using ASD occluder simultaneously. The average diameter of ISVD measured by TTE was (12.67±3.80), and the average diameter of sagittal axes and longitudinal axes measured by the 3D-printed model was (17.08±3.20) and (18.42±4.62) mm, respectively. The average size of PDA (diameter of pulmonary artery side) was (28.17±3.35) mm. Compared with the preoperative, the X-ray cardiothoracic ratio (0.51±0.04 vs. 0.47±0.06, P=0.007) and the right ventricle anterior-posterior diameter (31.17±5.65 vs. 24.58±3.75 mm, P<0.001) of postoperative was significantly decreased. During the average (47.75±27.52) months follow-up, it has achieved satisfying results, and there were no severe adverse events such as device transposition, death, and pericardial tamponade occurred.ConclusionsAssisting by 3D heart model, transcatheter closure of ISVD with PDA occluder had an excellent outcome. This method provides a new considerable treatment strategy for ISVD.