Effect of Elemental Powder Size on Foaming Behavior of NiTi Alloy Made by Combustion Synthesis

Nickel titanium (NiTi) foams were made by combustion synthesis of powders with the help of ZrH₂ as foaming agent and TiB₂ as endothermic agent. In this paper, we investigated the effect of elemental powder size on the foaming. The powder size of Ni and Ti affected the ignition temperature of the combustion reaction, cell morphology and microstructure of the foams. The cell morphology of the foams was also modified by the powder size of TiB₂.     

In vivo comparison of tantalum,tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double‐contrast dual‐energy CT of the bowel

To assess the ability of dual‐energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double‐contrast enhanced scans using iodinated intravenous contrast and experimental enteric non‐iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (?100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30–44% and 36–45%, both p < 0.001) higher for double‐contrast DECT than for conventional CT with enteric tungsten and tantalum contrast, respectively. Median small bowel wall visualization for double‐contrast DECT was scored 29 and 35 percentage points (95% CI 20–35% and 33–39%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Median completeness of intraluminal enteric contrast subtraction in double‐contrast DECT iodine density maps was scored 28 and 29 percentage points (95% CI 15–31% and 28–33%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Results suggest that in vivo double‐contrast DECT with iodinated intravenous and either tantalum‐ or tungsten‐based enteric contrast provides better visualization of small bowel than conventional CT. Copyright © 2016 John Wiley & Sons, Ltd.     

Repair of bone defects around dental implants with bone morphogenetic protein/fibroblast growth factor‐loaded porous calcium phosphate cement: a pilot study in a canine model

Objectives: To study the effects of the bone morphogenetic protein‐2 (BMP‐2)/fibroblast growth factor (bFGF)‐loaded porous calcium phosphate cement (CPC) on the repair of bone defects around dental implants. Material and methods: Thirty critical‐sized bone defects in beagle dogs were repaired with engineered bone composed of autologous bone‐marrow‐derived mesenchymal stem cells (BMSCs), BMP‐2, bFGF and CPC. Repairs were divided into six groups: BMSC/BMP‐2/bFGF/CPC, BMSC/BMP‐2/CPC, BMSC/bFGF/CPC, BMSC/CPC, CPC and no treatment. Polychrome sequential fluorescent labels were also performed post‐operatively. Fluorescence histological examinations of undecalcified sections at post‐operative week 12 were performed to clarify changes in the new bone around the dental implants. Results: The animals exhibited a perfect post‐operative course, with none experiencing any infection. Undecalcified sections showed that new bone was actively formed in the BMP‐2/bFGF group after 12 weeks. The bone mineralization apposition rate was better in the BMP‐2/bFGF group than in the other groups (P<0.05). Conclusion: BMP‐2 and bFGF together are more effective than either one alone in promoting the formation of new bone and may exert a synergistic activity at bone defects around dental implants. To cite this article:
Wang L, Zou D, Zhang S, Zhao J, K Pan, Huang Y. Repair of bone defects around dental implants with bone morphogenetic protein/fibroblast growth factor‐loaded porous calcium phosphate cement: a pilot study in a canine model.
Clin. Oral Impl. Res. 22 , 2011; 173–181.
doi: 10.1111/j.1600‐0501.2010.01976.x     

聚乙烯醇-盐酸普萘洛尔多孔水凝胶的制备及体外经皮渗透研究

目的：制备聚乙烯醇-盐酸普萘洛尔多孔水凝胶,并研究其体外经皮渗透性能。方法：采用循环冷冻-解冻法制备多孔水凝胶,采用改进的Franz扩散池进行体外透皮试验,以凝胶外观、致孔效果和累积渗透量为评价指标,优化水凝胶的处方和工艺。结果：壳聚糖与聚乙烯醇比例为1：3（W/W）时,凝胶具有较均匀的孔洞结构,平均孔径为10~50 μm,多孔凝胶的累积渗透量和皮肤滞留量均高于普通盐酸普萘洛尔凝胶。结论：所选处方工艺合理,制剂具有良好的透气性、经皮渗透性和皮肤粘着力,相较于普通凝胶,更适合婴幼儿患者使用。     

含镁多孔支架材料的体外抗菌活性和生物相容性

文题释义：快速成型：是一种材料加工方法,它是在现代CAD/CAM技术、激光技术、计算机数控技术、精密伺服驱动技术及新材料技术的基础上集成发展起来的。不同种类的快速成型系统因所用成形材料不同,成形原理和系统特点也各有不同,但基本原理都是“分层制造,逐层叠加”。 聚乳酸：是以乳酸为主要原料聚合得到的聚合物,具有良好的生物降解性、生物相容性以及延展性,但其机械强度不足,且降解后会产生酸性代谢产物,限制了其应用范围,常与其他一种或多种生物材料复合使用,以增强骨生物活性或生物力学强度。 背景：将多聚物材料与生物陶瓷材料复合制成有机/无机复合三维支架材料,可赋予支架骨传导所必需的理化特性,同时强化材料的力学性能,但大多数骨替代材料无法预防缺损部位的感染。研究发现由于镁的降解可产生局部碱性环境,使镁具有一定的抗菌活性。 目的：探讨含镁多孔支架材料的体外抗菌活性和细胞相容性。 方法：应用低温快速成型技术制备聚乳酸/β-磷酸三钙/镁多孔支架材料,其中β-磷酸三钙与镁的质量比分别为2∶1和1∶2,分别设为PTM(2∶1)组、PTM(1∶2)组;同时应用低温快速成型技术制备聚乳酸与聚乳酸/β-磷酸三钙多孔支架材料,分别设为P组、PT组。检测4组支架的表面形貌、孔径、孔隙率及压缩模量。将金黄色葡萄球菌(ATCC 35923)接种于4组支架表面24 h,通过涂板计数法和激光共聚焦显微镜观察材料的抗菌活性。将小鼠前成骨细胞MC3T3-E1分别与4组支架材料共培养,通过CCK-8法分析材料对细胞黏附和增殖的影响。 结果与结论：①4组支架材料表面都形成相对均匀的多孔结构,4组支架间孔径大小和孔隙率比较差异均无显著性意义(P > 0.05);②PTM(2∶1)组和PTM(1∶2)组压缩模量明显高于P组、PT组(P < 0.05),PTM(1∶2)组明显高于PTM(2∶1)组(P < 0.05);③涂板计数实验显示,PTM(2∶1)组、PTM(1∶2)组菌落形成单位明显低于P组、PT组(P < 0.05),其余组间比较差异无显著性意义(P > 0.05);④培养6 h,PT组、PTM(2∶1)组、PTM(1∶2)组黏附细胞数量多于P组(P < 0.05),PTM(2∶1)组和PTM(1∶2)组比较差异均无显著性意义(P > 0.05);⑤培养1 d时,仅PT组细胞增殖优于P组(P < 0.05);培养4,7 d时,PT组、PTM(2∶1)组、PTM(1∶2)组细胞增殖均优于P组(P < 0.05),PTM(2∶1)组和PTM(1∶2)组比较差异均无显著性意义(P > 0.05);⑥结果表明,聚乳酸/β-磷酸三钙/镁多孔支架材料不但具有良好的抗菌活性,而且具有优良的细胞相容性和一定的抗压能力。 ORCID: 0000-0002-3367-674X(马瑞) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

4D In-Situ Microscopy of Aerosol Filtration in a Wall Flow Filter

The transient nature of the internal pore structure of particulate wall flow filters, caused by the continuous deposition of particulate matter, makes studying their flow and filtration characteristics challenging. In this article we present a new methodology and first experimental demonstration of time resolved in-situ synchrotron micro X-ray computed tomography (micro-CT) to study aerosol filtration. We directly imaged in 4D (3D plus time) pore scale deposits of TiO2 nanoparticles (nominal mean primary diameter of 25 nm) with a pixel resolution of 1.6 μm. We obtained 3D tomograms at a rate of ∼1 per minute. The combined spatial and temporal resolution allows us to observe pore blocking and filling phenomena as they occur in the filter’s pore space. We quantified the reduction in filter porosity over time, from an initial porosity of 0.60 to a final porosity of 0.56 after 20 min. Furthermore, the penetration depth of particulate deposits and filtration rate was quantified. This novel image-based method offers valuable and statistically relevant insights into how the pore structure and function evolves during particulate filtration. Our data set will allow validation of simulations of automotive wall flow filters. Evolutions of this experimental design have potential for the study of a wide range of dry aerosol filters and could be directly applied to catalysed automotive wall flow filters.     

钽棒植入与骨瓣移植治疗成年人早期股骨头坏死的近期疗效对比

目的:比较髓芯减压联合金属钽棒植入术与带血管蒂髂骨瓣转移术治疗成年早期股骨头坏死(osteonecrosis of the femoral head,ONFH)的近期临床疗效.方法:回顾性收集本院2012年1月至2015年2月间收治的83例(97髋)非创伤性ONFH患者病历资料,A组43例52髋行髓芯减压并钽棒植入术,B组40例47髋,行自身带血管蒂髂骨瓣转移术,术后随访1年,比较两组手术参数指标、术后1年Harris髋关节功能评分及手术疗效.结果:A组手术时间(40.7±10.3) min、术中失血量(88.0±27.1) mL、术后镇痛泵应用时间(1.68±0.32)d、拆线天数(12.8±1.5)d均显著低于B组[(82.5±17.2) min,(239.4±45.2) mL,(2.15±0.48)d,(14.2±1.9)d;P＜0.05].两组术后12个月Harris总评分及各项目评分均较术前显著提高(P＜0.0s),A组术后Harris总评分(88.4±5.9)及关节功能评分(41.5±4.8)均显著高于B组[(83.6±5.3),(37.5±6.1);P＜0.05].两组术后12个月髋关节功能优良率均较术前显著提高(P＜0.05),A组术后12个月优良率(92.3％)显著高于B组(76.6％,P＜0.05).B组有1例出现髓塌陷,A组无髓塌陷病例.结论:髓芯减压联合金属钽棒植入术较带血管蒂髂骨瓣转移术治疗早期ONFH手术操作相对简单,近期疗效更为明显.     

多孔钽的理化/生物特性及其骨整合能力研究进展

近年来,以钛合金为主的骨骼材料得到了广泛的应用。临床研究中,植入体的腐蚀磨损和骨整合能力不足是造成其无菌性松动的主要原因,最终可导致手术失败。因此制备综合性能优越的植入体材料是骨组织工程研究的热点。多孔钽拥有良好的理化性质,耐腐蚀和抗磨损性能出色,其良好的生物相容性和多孔结构可以促进新骨的长入和成骨细胞的增殖,从而提高骨整合能力。并且表面改性技术的发展赋予了多孔钽更加优良的性能和功能,扩展了其临床应用。本文将针对多孔钽的理化/生物特性及其骨整合能力的研究进展进行综述。     

Heat Losses Caused by the Temporary Influence of Wind in Timber Frame Walls Insulated with Fibrous Materials

The paper presents the results of research concerning three fiber materials—mineral wool, hemp fiber and wood wool—as loose-fill thermal insulation materials. The analysis used the material parameters determined in previous works conducted by the authors, such as thermal conductivity and air permeability in relation to bulk density. These materials exhibit open porosity; thus, convection is an essential phenomenon in the heat transfer process. The paper aimed at conducting thermal simulations of various frame wall variants which were filled with the above-mentioned insulation materials. The simulations were performed with the Control Volume Method using the Delphin 5.8 software. The studies accounted for the effect of wind pressure and the time of its influence on a wall insulated by means of fiber material with a thickness of 150 as well as 250 mm. The simulation enabled us to obtain such data as maximal R-value reduction and time to return to equilibrium after filtration for the analyzed materials. The study proved that heat transfer in these insulations strongly depends on the bulk density, thickness of the insulation and wind pressure. The decrease in R is reduced as the density increases. This results from the decreased air permeability characterizing the material. Wind washing causes lower R reduction than air filtration in all models. The greater the thickness, the longer it takes for the models to return to the equilibrium state following air filtration (and wind washing). This period is comparable for air filtration and wind washing. Hemp fibers were characterized with the strongest susceptibility to air filtration; in the case of wood wool, it was also high, but lower than for hemp fibers, while mineral wool was characterized with the lowest.