A Histopathologic Study of Orbital Implant Vascularization

Purpose: To histopathologically assess the extent and pattern of vascularization of explanted porous polyethylene (PP) and hyrdoxyapatite (HA) orbital implants. To compare the vascularization in PP implants harvested after enucleation versus after evisceration. Methods: This is a comparative case series of six orbital implants explanted between 11 months and 5 years and 4 months post implantation. The implants were subjected to histopathological examination with various stains, after complete decalcification. Results: There were 2 post evisceration, 3 post enucleation and 1 secondary implant. The size of the implants varied from 18 to 23 mm diameter. The reason for explantation was exposure in all the 6 cases with additional infection in 2 cases. Histopathology revealed complete vascularization up to the core of the implant in all the cases. There was evidence of chronic inflammation within all the explanted specimens. Acute inflammation was present at the site of exposure in four of the implants. Three of these implants had additional evidence of necrosis. Two cases with clinically evident infection had Gram positive cocci within the implant. Foreign-body type giant-cells, melanophages and haemosiderin laden macrophages were also observed. Eviscerated specimens showed scleral remodelling and thickening. Conclusion: All the implants were vascularized up to the core. There was histologic evidence of chronic inflammation in all the explanted implants possibly indicating the foreign nature of the implant material. The sclera did not impede vascularization of the implants in eviscerated specimens. We found no difference in the degree of vascularization of the implant in enucleated versus eviscerated implants.     

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.     

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.     

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。     

力学参数随深度变化的关节软骨数值模拟

目的在软骨数值模拟中,对由于设置均匀和随深度变化的力学参数而导致的结果差异进行评估。方法利用COMSOL多孔介质模块建立软骨非线性两相多孔介质模型。在静载荷下,分别用均匀和随深度变化的两种软骨力学参数对模型进行了计算,并对两者的计算结果差异进行了分析。结果对于软骨总应力,两种参数设置的结果之间差异很小。但在分析软骨的固相应力、液体压力和流动等较深入细致的问题时,两种参数设置结果之间的差异不能忽略。结论不同的软骨力学参数设置对软骨总应力的结果几乎没有影响,但对软骨内流速场则影响很大。所以均匀的力学参数设置可用来简化计算软骨总应力的问题,而其他一些更细致的分析需要立足于随深度变化的软骨力学参数。这些结论可以为今后的软骨建模和数值计算提供参考,为人工关节的设计和计算奠定基础。     

A novel therapeutic design of microporous-structured biopolymer scaffolds for drug loading and delivery

Three-dimensional (3-D) open-channeled scaffolds of biopolymers are a promising candidate matrix for tissue engineering. When scaffolds have the capacity to deliver bioactive molecules the potential for tissue regeneration should be greatly enhanced. In order to improve drug-delivery capacity, we exploit 3-D poly(lactic acid) (PLA) scaffolds by creating microporosity within the scaffold network. Macroporous channeled PLA with a controlled pore configuration was obtained by a robotic dispensing technique. In particular, a room temperature ionic liquid (RTIL) bearing hydrophilic counter-anions, such as OTf and Cl, was introduced to the biopolymer solution at varying ratios. The RTIL–biopolymer slurry was homogenized by ultrasonication, and then solidified through the robotic dispensing process, during which the biopolymer and RTIL formed a bicontinuous interpenetrating network. After ethanol wash-out treatment the RTIL was completely removed to leave highly microporous open channels throughout the PLA network. The resultant pore size was observed to be a few micrometers (average 2.43 μm) and microporosity was determined to be ∼70%. The microporous surface was also shown to favor initial cell adhesion, stimulating cell anchorage on the microporous structure. Furthermore, in vivo tissue responses assessed in rat subcutaneous tissue revealed good tissue compatibility, with minimal inflammatory reactions, while gathering a larger population of fibroblastic cells than the non-microporous scaffolds, and even facilitating invasion of the cells within the microporous structure. The efficacy of the micropore networks generated within the 3-D scaffolds in loading and releasing therapeutic molecules was addressed using antibiotic sodium ampicillin and protein cytochrome C as model drugs. The microporous scaffolds exhibited significantly enhanced drug loading capacity: 4–5 times increase in ampicillin and 9–10 times increase in cytochrome C compared to the non-microporous scaffolds. The release of ampicillin loaded within the microporous scaffolds was initially fast (∼85% for 1 week), and was then slowed down, showing a continual release up to a month. On the other hand, cytochrome C was shown to release in a highly sustainable manner over a month, without showing an initial burst release effect. This study provides a novel insight into the generation of 3-D biopolymer scaffolds with high performance in loading and delivery of biomolecules, facilitated by the creation of microporous channels through the scaffold network. The capacity to support tissue cells while in situ delivering drug molecules makes the current scaffolds potentially useful for therapeutic tissue engineering.     

基于增材制造技术修复缺损颅骨的研究和应用

该文运用增材制造技术快速制备三维重建的缺损颅骨植入体,通过对骨植入体材料对比分析,选择多孔羟基磷灰石材料应用于颅骨植入手术中。运用Mimics 10.0软件对临床计算机断层扫描(CT)影像数据重建三维植人体模型,采用增材制造技术制备多孔羟基磷灰石颅骨植入体,与颅骨贴合度好,表面光滑平顺,而多孔羟基磷灰石能够引导和诱导骨的形成,大大提高其生物相容性。增材制造技术快速制备的特点促使个性化颅骨修补植入物成为可能,个性化医用三维模型用于植入手术降低手术风险,术后效果好,具有推广应用的前景。     

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     

Anomalous front broadening during spontaneous imbibition in a matrix with elongated pores

During spontaneous imbibition, a wetting liquid is drawn into a porous medium by capillary forces. In systems with comparable pore length and diameter, such as paper and sand, the front of the propagating liquid forms a continuous interface. Sections of this interface advance in a highly correlated manner due to an effective surface tension, which restricts front broadening. Here we investigate water imbibition in a nanoporous glass (Vycor) in which the pores are much longer than they are wide. In this case, no continuous liquid-vapor interface with coalesced menisci can form. Anomalously fast imbibition front roughening is experimentally observed by neutron imaging. We propose a theoretical pore-network model, whose structural details are adapted to the microscopic pore structure of Vycor glass and show that it displays the same large-scale roughening characteristics as observed in the experiment. The model predicts that menisci movements are uncorrelated, indicating that despite the connectivity of the network the smoothening effect of surface tension on the imbibition front roughening is negligible. These results suggest a new universality class of imbibition behavior, which is expected to occur in any matrix with elongated, interconnected pores of random radii.