食管超声下钛夹基准标记对食管癌内扩边变化的评估作用

目的：通过实时透视食管超声下置入的钛夹位移,评估食管病灶内扩边的影响因素及变化规律。方法对60例食管癌患者,食管超声探察病灶,病灶的上下端置入金属钛夹做基准标记,在模拟放疗体位下直接采集透视图像分析,分别记录平静呼吸和屏气状态下钛夹的空间位移。结果60例患者完成试验,74个病灶,137枚钛夹被置入。透视观察到134个（97．8％）,钛夹脱落中位时间为23天,无Ⅲ度以上钛夹置入相关性不良反应。钛夹运动呈规律性振动,振动频率与呼吸运动和心脏搏动相关。在平静呼吸状态下,钛夹移动的极值和中值分别为：头脚方向：（0．7～14．0 mm,7．5 mm）、左右方向（0．4～5．6 mm,2．0 mm）、前后方向（0．6～9．0 mm,2．3 mm）;在屏气状态下,钛夹移动的极值和中值分别为：头脚方向（0．2～3．3 mm,1．5 mm）、左右方向（0．2～3．3 mm,1．1 mm）、前后方向（0．3～3．7 mm,1．5 mm）。结论呼吸运动、心脏搏动、食管病灶位置影响食管病灶内扩边值,其中呼吸运动是主要因素。食管超声钛夹基准标记下的实时透视技术,安全可靠。     

Tailoring Titanium Sheet Metal Using Laser Metal Deposition to Improve Room Temperature Single-Point Incremental Forming

Typically, due to their limited formability, elevated temperatures are required in order to achieve complex shapes in titanium alloys. However, there are opportunities for forming such alloys at room temperature using incremental forming processes such as single-point incremental forming (SPIF). SPIF is an innovative metal forming technology which uses a single tool to form sheet parts in place of dedicated dies. SPIFs ability to increase the forming limits of difficult-to-form materials offers an alternative to high temperature processing of titanium. However, sheet thinning during SPIF may encourage the early onset of fracture, compromising in-service performance. An additive step prior to SPIF has been examined to tailor the initial sheet thickness to achieve a homogeneous thickness distribution in the final part. In the present research, laser metal deposition (LMD) was used to locally thicken a commercially pure titanium grade 2 (CP-Ti50A) sheet. Tensile testing was used to examine the mechanical behaviour of the tailored material. In addition, in-situ digital image correlation was used to measure the strain distribution across the surface of the tailored material. The work found that following deposition, isotropic mechanical properties were obtained within the sheet plane in contrast to the anisotropic properties of the as-received material and build height appeared to have little influence on strength. Microstructural analysis showed a change to the material in response to the LMD added thickness, with a heat affected zone (HAZ) at the interface between the added LMD layer and non-transformed substrate material. Grain growth and intragranular misorientation in the added LMD material was observed. SPIF of a LMD tailored preform resulted in improved thickness homogeneity across the formed part, with the downside of early fracture in a high wall angle section of the sheet.     

钛种植体-骨间隙愈合界面成骨方式的激光共聚焦显微镜观察

目的：观察钛种植体一骨界面的新生骨形成情况,探讨在间隙愈合模型中种植体和骨表面是否存在双向成骨现象。方法：将4枚带有环形凹槽的纯钛种植体经喷砂、酸蚀处理后,植入兔股骨远端髁突内。术后第5d和第19d分别肌肉注射钙黄绿素和茜素红。采用激光共聚焦显微镜观察带种植体的硬组织切片。结果：激光共聚焦显微镜显示,种植体的间隙区域均有新生骨组织生成。在间隙区域,骨创面和相应的种植体表面分别存在绿色荧光带（钙黄绿素）,二者问不连续,而在19d时注射的茜素红所标记的红色荧光将二者连接融合,并可见大量红色荧光分布于绿色荧光周围。结论：种植体一骨界面存在远端成骨和接触成骨2种成骨方式,二者相向成骨。     

人工唾液和乳酸对钛合金卡环疲劳强度影响的研究

目的:探讨人工唾液和乳酸对钛合金卡环疲劳强度的影响.方法:用成品卡环蜡型制作钛合金卡环15个,分为3组,分别在空气中、人工唾液和乳酸溶液中进行测试,初始载荷强度和疲劳失效前的载荷循环次数被自动记录.疲劳裂纹进行扫描电镜分析.结果:钛合金卡环在不同测试条件下的初始载荷强度无差异(P＞0.05).在空气中的循环次数最高,在乳酸溶液中的循环次数最低.SPSS软件分析表明3组之间的疲劳强度有显著性差异(P＜0.01).结论:结果表明人工唾液和乳酸溶液均使钛合金卡环的疲劳强度下降.     

L5新型自稳定人工椎体生物力学性能的有限元分析

目的:采用有限元分析评估L5椎体次全切术后置入新型自稳定人工椎体的力学性能以及对周围组织的影响,为腰骶段脊柱结核等疾病的治疗提供新的选择.方法:提取1名健康志愿者腰骶段CT薄层扫描数据进行三维重建,构建腰骶段(L3-S1)脊柱生理组有限元模型并进行有效性验证.将L5椎体及邻近椎间盘切除后,分别置入新型自稳定人工椎体和钛...     

聚醚醚酮椎体间融合器和钛网用于前路减压植骨融合术治疗脊髓型颈椎病的对比研究

目的比较聚醚醚酮（PEEK）椎体间融合器和钛网在前路减压植骨融合术中应用的临床及放射线治疗效果。方法选择2011年6月～2012年6月期间21例脊髓型颈椎病拟行前路减压植骨融合术的患者,男15例,女6例,年龄46～62岁,并进行了相关评估;随机分为PEEK组（n=13）采用PEEK椎体间融合器融合术和钛网组（n=8）采用钛质网笼融合术。测量并记录两组患者的节段矢状测角、颈椎前凸和融合段高度。结果 PEEK组节段矢状测角的提高比钛网组中的成功率高16.67%（P〈0.05）,虽然颈椎前凸损失在两组中差异无统计学意义（P〉0.05）,但在钛网组中的患者融合段高度比PEEK组提高了11.12%（P〈0.05）。结论 PEEK椎体间融合器在改善颈椎曲度方面优于钛网,然而钛网在维持融合段高度方面比PEEK融合器好。     

Seawater activated TiO2 photocatalyst for degradation of organic compounds

The world's oceans are polluted by a continuous inflow of plastic. Plastic fragments finally into microplastic, which can be taken up, for example by plankton, and subsequently by the entire ocean food web. An approach to reduce plastic pollution constitutes the accelerated microplastic degradation in marine environments. TiO₂ (anatase) is commonly used as an oxidative photocatalyst and well known to catalyze the degradation of organic compounds upon UV irradiation.In this study, a selective activation of TiO₂ (anatase) particles encapsulated by Ca- or Sr-polyphosphate is presented. The TiO₂ polyphosphate core-shell particles are envisaged as additives in plastic products. The highly concentrated cations from seawater, viz. Na⁺ and Mg²⁺, displace the Ca²⁺ or Sr²⁺ cations from the polyphosphate shell. As a result, the polyphosphate coating dissolves and thus the photocatalytically active TiO₂ core is released. The stability of the TiO₂ polyphosphate particles in potable water and the seawater activated disintegration of methylene blue, methyl methacrylate, terephtalic acid, and poly(vinyl alcohol) was shown. It has been demonstrated, that the sweetwater stable polyphosphate coating degrades in the presence of seawater, which could be monitored by the activation of the TiO₂ (anatase) photocatalyst.     

Biomechanical investigation of maxillary implant-supported full-arch prostheses produced with different framework materials: a finite elements study

PURPOSEFour and six implant-supported fixed full-arch prostheses with various framework materials were assessed under different loading conditions.MATERIALS AND METHODSIn the edentulous maxilla, the implants were positioned in a configuration of four to six implant modalities. CoCr, Ti, ZrO₂, and PEEK materials were used to produce the prosthetic structure. Using finite element stress analysis, the first molar was subjected to a 200 N axial and 45° oblique force. Stresses were measured on the bone, implants, abutment screw, abutment, and prosthetic screw. The Von Mises, maximum, and minimum principal stress values were calculated and compared.RESULTSThe maximum and minimum principal stresses in bone were determined as CoCr < ZrO₂ < Ti < PEEK. The Von Mises stresses on the implant, implant screw, abutment, and prosthetic screws were determined as CoCr < ZrO₂ < Ti < PEEK. The highest Von Mises stress was 9584.4 Mpa in PEEK material on the prosthetic screw under 4 implant-oblique loading. The highest maximum principal stress value in bone was found to be 120.89 Mpa, for PEEK in 4 implant-oblique loading.CONCLUSIONFor four and six implant-supported structures, and depending on the loading condition, the system accumulated different stresses. The distribution of stress was reduced in materials with a high elastic modulus. When choosing materials for implant-supported fixed prostheses, it is essential to consider both the number of implants and the mechanical and physical attributes of the framework material.     

微型金属钛板内固定在下颌骨骨折中的应用

目的　总结分析微型钛板在下颌骨骨折中的应用特点。方法　对 2 5例各种类型的下颌骨骨折采用微型钛板手术内固定。结果　所有病例骨折对位良好 ,骨愈合正常 ,有 1例钛螺钉松动而取出钛板。结论　微型钛板坚固内固定适用于各种下颌骨骨折 ,只要手术时处置得当 ,疗效令人满意。     

口内切口与牵引钉暂时颌间刚性牵引固定治疗下颌骨骨折45例分析

目的:评价术中利用颌间牵引螺丝暂时牵引,经口内切口进行整复并坚强内固定治疗45例下颌骨骨折的效果。方法:对45例54处下颌体及下颌角区线性骨折,先分别在上、下颌中切牙之间、尖牙与第一前磨牙之间、第一与第二磨牙之间的根向植入颌间牵引螺丝,骨折复位后,进行颌间结扎固定,恢复咬合关系及下颌骨的弓型。自下颌前庭沟、翼下颌皱襞切开黏骨膜,显露骨折处并复位后,在张力线上用小型钛板进行坚强内固定术。术毕拆除颌间结扎,7d后将颌间牵引螺丝拆除。分别于术后第1天和第90天进行临床和X线检查,评价其咬合关系、骨折复位及愈合情况。结果:45例54处下颌骨骨折均获得良好的复位和骨性愈合,咬合关系良好,无明显并发症。结论:经口内途径行小型钛板坚强内固定术,结合颌间牵引螺丝暂时刚性牵引结扎,对下颌体及下颌角骨折的整复固定和功能恢复效果良好。