电磁导航支气管镜引导下肺结节定位和CT引导下Hook-wire穿刺定位在肺癌根治术中的应用效果及安全性比较

目的对比电磁导航支气管镜(ENB)引导下肺结节定位和CT引导下Hook-wire穿刺定位在肺癌根治术中的应用效果和安全性。方法将87例行肺癌根治术患者根据定位方式的不同分为CT组(n=45,行CT引导下Hook-wire穿刺定位)和ENB组(n=42,行ENB引导下肺结节定位)。比较两组患者手术情况、切缘阳性率、心肺功能指标、应激指标和并发症发生情况。结果ENB组患者定位时间、定位后等待时间均短于CT组,差异均有统计学意义(P﹤0.05)。术后7天,两组患者左心室射血分数(LVEF)、每搏量(SV)、用力肺活量(FVC)均较术前降低,但ENB组患者LVEF、SV、FVC均高于CT组,差异均有统计学意义(P﹤0.05)。术后1天,两组患者白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、C反应蛋白(CRP)、皮质醇(Cor)水平均较术前升高,但ENB组患者IL-6、IL-8、CRP、Cor水平均低于CT组,差异均有统计学意义(P﹤0.05)。两组患者并发症总发生率比较,差异无统计学意义(P﹥0.05)。结论相比于CT引导下Hook-wire穿刺定位,ENB引导下肺结节定位的定位时间和定位后等待时间更短,能够更加有效地改善患者的心肺功能,减轻应激反应。

CT引导下Hook-wire定位辅助胸腔镜手术对早期肺癌患者的疗效分析

目的探讨CT引导下Hook-wire定位辅助胸腔镜手术对早期肺癌患者的疗效。方法选取92例早期肺癌患者,按随机数字表法分为两组,各46例。对照组行常规胸腔镜手术治疗,观察组行CT引导下Hook-wire定位辅助胸腔镜手术治疗。比较两组手术情况、创伤应激指标、肿瘤标志物水平及并发症。结果观察组手术时间、术后引流时间及住院时间为(138.52±10.52)min、(3.12±0.45)d、(10.35±1.25)d,短于对照组,术中出血量为(105.41±12.36)ml,少于对照组,差异有统计学意义(P<0.05);观察组术后皮质醇(Cor)、去甲肾上腺素(NE)、C反应蛋白(CRP)水平分别为(118.52±8.36)ng/ml、(185.93±14.52)ng/L、(32.41±4.25)mg/L,低于对照组,差异有统计学意义(P<0.05);观察组术后癌胚抗原(CEA)、细胞角蛋白19片段抗原21-1(CYFRA21-1)、糖类抗原125(CA125)水平为(8.96±1.15)ng/ml、(3.88±0.42)ng/ml、(12.63±1.54)U/ml,低于对照组,并发症少于对照组,差异有统计学意义(P<0.05)。结论CT引导下Hook-wire定位辅助胸腔镜手术治疗早期肺癌效果更佳,可减轻手术创伤,降低创伤应激反应,加快肿瘤标志物复常,减少并发症发生。

定位丝与Hook-wire在肺小结节胸腔镜术前定位中的应用比较

目的:比较定位丝与Hook-wire两种定位技术在肺小结节患者胸腔镜术前定位中的有效性和安全性。方法:回顾并分析119例胸腔镜术前计算机体层成像(computed tomography,CT)引导下经皮穿刺定位的肺小结节患者的临床资料,根据不同定位方法分为定位丝组(50例)和Hook-wire组(69例),比较两组间的结节位置、结节直径、结节至胸膜的距离、定位时间、定位成功率及并发症发生率的差异,对定位后并发症的相关因素进行logistic回归分析。结果:两组间的结节位置、结节直径、结节至胸膜的距离差异无统计学意义。定位丝组与Hook-wire组定位时间相近[16(14,19)min vs 16(14,18.5)min,t=-0.416,P=0.677]。定位丝组与Hook-wire组定位成功率相近(98.0%vs 94.2%,χ^(2)=1.038,P=0.397)。定位丝组总体并发症发生率低于Hook-wire组(16.0%vs 47.8%,χ^(2)=13.003,P<0.001),亚组分析中定位丝组的气胸(12.0%vs 27.5%,χ^(2)=4.217,P=0.044)、肺出血(4.0%vs 18.8%,χ^(2)=5.796,P=0.016)、局部疼痛(0.0%vs 8.7%,χ^(2)=4.579,P<0.001)的发生率均低于Hook-wire组。Logistic回归分析结果显示,不同的定位方法是本研究中肺小结节患者胸腔镜术前定位后是否有并发症的独立危险因素(OR=0.208,95%CI 0.085~0.507,P<0.001)。结论:定位丝法定位时间、定位成功率与Hook-wire法相近,但定位丝法较Hook-wire法并发症少,值得推广。

CT引导下Hook-wire穿刺定位在肺部小结节胸腔镜手术中的应用效果

目的研究术前CT引导下肺部小结节Hook-wire穿刺定位在基层医院运用中的可行性、安全性。方法回顾性分析2021年1月1日至2022年12月31日在我院因肺部小结行术前CT引导穿刺定位行手术的患者,共计70例。对所有患者均实施CT引导下Hook-wire穿刺定位开展胸腔镜手术,对患者的手术穿刺情况、手术方式及相关手术指标变化情况进行观察与记录。结果70例患者中,69例术前定位在小结节附近2 cm内,1例因穿刺针从叶裂经过而出现偏差,70例穿刺定位均未穿刺入小结节内,部位穿刺深度(5 mm~2 cm),穿刺时间(4~8 min),气胸(7例),血胸(2例),穿刺部位略感胀痛;手术方式(胸腔镜下肺楔形切除48例,胸腔镜下肺段切除15例,胸腔镜下肺叶切除术7例),术中发现定位针均位于肺组织中未发现脱落,牵引线未发现断裂,术后病理(原位癌15例,微浸润腺癌42例,浸润腺癌13例),术后随访中穿刺部位无疼痛等不适。结论术前CT引导Hook-wire穿刺定位技术在基层医院胸腔镜手术中的运用安全、有效,完全满足基层医院胸外科医师开展肺部小结节的手术要求,对定位精度要求相对低、并发症少、患者疼痛轻、定位时间短、费用低,适合在基层医院中开展。

术前CT引导下Hook-wire定位与医用胶定位在磨玻璃结节为主的早期肺癌术中的应用效果比较

目的 对比术前CT引导下Hook-wire与医用胶定位在磨玻璃结节为主的早期肺癌手术切除中的应用效果。方法 回顾性分析83例以磨玻璃结节为主的早期肺癌切除术患者的临床资料,根据其术前结节定位方法将其分为Hook-wire组(CT引导下Hook-wire定位,n=30)与医用胶组(CT引导下医用胶定位,n=53),比较两组定位成功率、平均定位耗时、病灶精确切除率、病灶平均切除时间、定位相关并发症、术后住院时间等。结果 医用胶组与Hook-wire组平均定位耗时、结节切除耗时、术后住院时间及手术相关并发症发生率比较,差异无统计学意义(P>0.05),医用胶组定位成功率高于Hook-wire组,定位相关并发症发生率低于Hook-wire组,结节精准切除率高于Hook-wire组,差异均有统计学意义(P<0.05)。结论 相比于Hookwire,CT引导下医用胶定位GGN的效果更好,安全性更高。

肺结节定位针和Hook-wire在肺结节术前定位中的应用比较

目的:探讨术前CT引导下新型肺结节定位针和Hook-wire定位针在肺小结节胸腔镜切除术中的应用价值,为术前定位方法的选择提供更多循证证据。方法:回顾性分析2022年1月—2022年10月于天津医科大学总医院心胸外科接受胸腔镜手术治疗肺结节,并在术前接受肺结节定位的80例患者的临床资料,根据定位针种类不同分为Hook-wire组和新型肺结节定位针组。Hook-wire定位针组患者接受术前CT引导下肺结节Hook-wire定位,新型肺结节定位针组患者接受术前CT引导下肺结节定位,比较两组定位效果及患者预后情况。结果:新型肺结节定位针组的定位后疼痛评分和移位或脱钩发生率均明显低于Hook-wire组,差异有统计学意义(χ^(2)=-6.671;t=3.914,P<0.05)。结论:肺小结节胸腔镜切除术前采用CT引导新型肺结节定位针定位能有效降低钩丝移位或脱钩风险并减轻定位后疼痛。

CT引导下Hook-wire定位联合电视胸腔镜手术治疗早期肺癌患者的效果

目的:观察CT引导下Hook-wire定位联合电视胸腔镜手术(VATS)治疗早期肺癌患者的效果。方法:选取2019年2月至2021年9月该院收治的106例早期肺癌患者进行前瞻性研究,按随机数字表法将其分为对照组和观察组各53例。对照组接受VATS治疗,观察组接受CT引导下Hook-wire定位联合VATS治疗。比较两组手术相关指标(术中出血量、住院时间、手术时间、胸腔引流时间、切缘阳性率、淋巴结清扫数目)水平、手术前后心肺功能指标[左心室射血分数(LVEF)、每搏输出量(SV)、最大通气量(MVV)、用力肺活量(FVC)]水平、血清血管内皮生长因子(VEGF)-A水平、VEGF受体2(VEGFR2)水平、创伤应激反应指标[超氧化物歧化酶(SOD)、皮质醇(Cor)、丙二醛(MDA)]水平,以及并发症发生率。结果:观察组住院时间、手术时间和胸腔引流时间短于对照组,术中出血量少于对照组,淋巴结清扫数目多于对照组,切缘阳性率低于对照组,差异均有统计学意义(P<0.05);术后7、14 d,观察组LVEF、SV、FVC、MVV水平均高于对照组,血清VEGF-A、VEGFR2水平均低于对照组,差异有统计学意义(P<0.05);术后1、3 d,两组血清SOD水平均低于术前,但观察组高于对照组,两组血清Cor、MDA水平均高于术前,但观察组低于对照组,差异有统计学意义(P<0.05);观察组并发症发生率为3.77%(2/53),低于对照组的20.75%(11/53),差异有统计学意义(P<0.05)。结论:CT引导下Hook-wire定位联合VATS治疗早期肺癌患者可提高心肺功能,改善手术相关指标和创伤应激反应指标水平,以及降低VEGF-A、VEGFR2水平和并发症发生率,效果优于单纯VATS治疗。

CT引导下Hook-wire定位配合胸腔镜手术对早期肺癌患者切缘阳性率及并发症的影响

目的探究CT引导下Hook-wire定位辅助胸腔镜手术(TS)治疗早期肺癌的疗效。方法依据不同手术方法将本院2017年4月~2021年5月收治的早期肺癌患者80例分为定位组(41例)和胸腔镜组(39例)。胸腔镜组给予TS,定位组在实施TS前以CT引导下Hook-wire进行定位。对比两组手术指标、手术前后细胞免疫功能(T淋巴细胞CD3^(+)、CD4^(+)、CD8^(+)、CD4^(+)/CD8^(+))、肺功能[一氧化碳弥散量(DLCO)、用力肺活量(FVC)、每分钟最大通气量(MVV)]、并发症及复发情况。结果定位组术中出血量少于胸腔镜组,手术、术后引流、住院时间均短于胸腔镜组,差异有统计学意义(P<0.05);术后3d定位组CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+)水平高于胸腔镜组,CD8+水平低于胸腔镜组,差异均有统计学意义(P<0.05);术后1个月定位组FVC、DLCO、MVV高于胸腔镜组,差异均有统计学意义(P<0.05);定位组切缘阳性率(2.44%)、并发症总发生率(7.32%)及随访1年复发率(2.63%)与胸腔镜组(10.26%、15.38%、17.65%)比较差异无统计学意义(P>0.05)。结论早期肺癌患者实施TS前在CT引导下Hook-wire进行定位能降低操作难度,优化手术情况,减轻肺功能、免疫功能损伤。

Expert Experience and Data-Driven Based Hybrid Fault Diagnosis for High-SpeedWire Rod Finishing Mills

The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system.

High formability Mg-Zn-Gd wire facilitates ACL reconstruction via its swift degradation to accelerate intra-tunnel endochondral ossification

After reconstructing the anterior cruciate ligament(ACL),unsatisfactory bone tendon interface healing may often induce tunnel enlargement at the early healing stage.With good biological features and high formability,Magnesium-Zinc-Gadolinium(ZG21)wires are developed to bunch the tendon graft for matching the bone tunnel during transplantation.Microstructure,tensile strength,degradation,and cytotoxicity of ZG21 wire are evaluated.The rabbit model is used for assessing the biological effects of ZG21 wire by Micro-CT,histology,and mechanical test.The SEM/EDS,immunochemistry,and in vitro assessments are performed to investigate the underlying mechanism.Material tests demonstrate the high formability of ZG21 wire as surgical suture.Micro-CT shows ZG21 wire degradation accelerates tunnel bone formation,and histologically with earlier and more fibrocartilage regeneration at the healing interface.The mechanical test shows higher ultimate load in the ZG21 group.The SEM/EDS presents ZG21 wire degradation triggered calcium phosphate(Ca-P)deposition.IHC results demonstrate upregulation of Wnt3a,BMP2,and VEGF at the early phase and TGFβ3 and Type II collagen at the late phase of healing.In vitro tests also confirmed the Ca-P in the metal extract could elevate the expression of Wnt3a,βcatenin,ocn and opn to stimulate osteogenesis.Ex vivo tests of clinical samples indicated suturing with ZG21 wire did not weaken the ultimate loading of human tendon tissue.In conclusion,the ZG21 wire is feasible for tendon graft bunching.Its degradation products accelerated intra-tunnel endochondral ossification at the early healing stage and therefore enhanced bone-tendon interface healing in ACL reconstruction.

3D reconstruction and defect pattern recognition of bonding wire based on stereo vision

Non-destructive detection of wire bonding defects in integrated circuits(IC)is critical for ensuring product quality after packaging.Image-processing-based methods do not provide a detailed evaluation of the three-dimensional defects of the bonding wire.Therefore,a method of 3D reconstruction and pattern recognition of wire defects based on stereo vision,which can achieve non-destructive detection of bonding wire defects is proposed.The contour features of bonding wires and other electronic components in the depth image is analysed to complete the 3D reconstruction of the bonding wires.Especially to filter the noisy point cloud and obtain an accurate point cloud of the bonding wire surface,a point cloud segmentation method based on spatial surface feature detection(SFD)was proposed.SFD can extract more distinct features from the bonding wire surface during the point cloud segmentation process.Furthermore,in the defect detection process,a directional discretisation descriptor with multiple local normal vectors is designed for defect pattern recognition of bonding wires.The descriptor combines local and global features of wire and can describe the spatial variation trends and structural features of wires.The experimental results show that the method can complete the 3D reconstruction and defect pattern recognition of bonding wires,and the average accuracy of defect recognition is 96.47%,which meets the production requirements of bonding wire defect detection.

Robust interface and excellent as-built mechanical properties of Ti–6Al–4V fabricated through laser-aided additive manufacturing with powder and wire

The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.

Effect of wire diameter compression ratio on drawing deformation of micro copper wire

A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated.Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip zones.Additionally,horizontal strain concentration bands develop within the drawn wire.As the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also increase.However,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process.

Capillary Property of Entangled Porous Metallic Wire materials and Its Application in Fluid Buffers:Theoretical Analysis and Experimental Study

Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment(such as artillery,mortar,etc.).Combined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM.The calculation model of the damping force of the composite buffer was established.The low-speed impact test of the composite buffer was conducted.The parameters of the buffer under low-speed impact were identified according to the model,and the nonlinear model of damping force was obtained.The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).

Customized heat treatment process enabled excellent mechanical properties in wire arc additively manufactured Mg-RE-Zn-Zr alloys

Customized heat treatment is essential for enhancing the mechanical properties of additively manufactured metallic materials,especially for alloys with complex phase constituents and heterogenous microstructure.However,the interrelated evolutions of different microstructure features make it difficult to establish optimal heat treatment processes.Herein,we proposed a method for customized heat treatment process exploration and establishment to overcome this challenge for such kind of alloys,and a wire arc additively manufactured(WAAM)Mg-Gd-Y-Zn-Zr alloy with layered heterostructure was used for feasibility verification.Through this method,the optimal microstructures(fine grain,controllable amount of long period stacking ordered(LPSO)structure and nano-scaleβ'precipitates)and the corresponding customized heat treatment processes(520°C/30 min+200°C/48 h)were obtained to achieve a good combination of a high strength of 364 MPa and a considerable elongation of 6.2%,which surpassed those of other state-of-the-art WAAM-processed Mg alloys.Furthermore,we evidenced that the favorable effect of the undeformed LPSO structures on the mechanical properties was emphasized only when the nano-scaleβ'precipitates were present.It is believed that the findings promote the application of magnesium alloy workpieces and help to establish customized heat treatment processes for additively manufactured materials.

Mechanical property of cylindrical sandwich shell with gradient core of entangled wire mesh

To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.

Selection of Fe as a barrier for manufacturing low-cost MgB2 multifilament wires-Advanced microscopy study between Fe and B reaction

The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niobium-titanium superconductors.The potential of replacing the Nb barrier with a low-cost iron(Fe)barrier for multifilament MgB2 superconducting wires is investigated in this manuscript.Therefore,MgB2 wires with Fe barrier sintered with different temperatures are studied(from 650°C to 900°C for 1 h)to investigate the non-superconducting reaction phase of Fe-B.Their superconducting performance including engineering critical current density(Je)and n-value are tested at 4.2 K in various external magnetic fields.The best sample sintered at 650°C for 1 h has achieved a Je value of 3.64×10^(4) A cm^(−2) and an n-value of 61 in 2 T magnetic field due to the reduced formation of Fe2B,better grain connectivity and homogenous microstructure.For microstructural analysis,the focused ion beam(FIB)is utilised for the first time to acquire three-dimensional microstructures and elemental mappings of the interface between the Fe barrier and MgB2 core of different wires.The results have shown that if the sintering temperature can be controlled properly,the Je and n-value of the wire are still acceptable for magnet applications.The formation of Fe2B is identified along the edge of MgB2,as the temperature increases,the content of Fe2B also increases which causes the degradation in the performance of wires.

Modeling asymmetric fracture mechanics of Mg alloy wire in drawing process

In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression region.The aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress states.The wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)model.The damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack initiation.Computational analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this approach.The proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.

Mass transfer enhancement and hydrodynamic performance with wire mesh coupling solid particles in bubble column reactor

It is of vital significance to investigate mass transfer enhancements for chemical engineering processes.This work focuses on investigating the coupling influence of embedding wire mesh and adding solid particles on bubble motion and gas-liquid mass transfer process in a bubble column.Particle image velocimetry(PIV)technology was employed to analyze the flow field and bubble motion behavior,and dynamic oxygen absorption technology was used to measure the gas-liquid volumetric mass transfer coefficient(kLa).The effect of embedding wire mesh,adding solid particles,and wire mesh coupling solid particles on the flow characteristic and kLa were analyzed and compared.The results show that the gas-liquid interface area increases by 33%-72%when using the wire mesh coupling solid particles strategy compared to the gas-liquid two-phase flow,which is superior to the other two strengthening methods.Compared with the system without reinforcement,kLa in the bubble column increased by 0.5-1.8 times with wire mesh coupling solid particles method,which is higher than the sum of kLa increases with inserting wire mesh and adding particles,and the coupling reinforcement mechanism for affecting gas-liquid mass transfer process was discussed to provide a new idea for enhancing gas-liquid mass transfer.

In vivo and in vitro study of resorbable magnesium wires for medical implants:Mg purity,surface quality,Zn alloying and polymer coating

Magnesium is an excellent material in terms of biocompatibility and its corrosion products can serve as an active source for new bone formation.However,localized corrosion and H_(2)generation limit the potential of Mg-based implants.Utilizing low-alloyed Mg-Zn wires can strongly reduce problems with large H_(2)bubbles and improve the mechanical properties considerably while maintaining excellent long-term biocompatibility.Acidic pickling and a polymer coating can be effectively used to lower the rate of in vivo degradation.In this work,microstructural,mechanical,and in vitro characterization of 250μm and 300μm extruded wires made from ultra-pure Mg,commercially pure Mg,Mg-0.15Zn,Mg-0.4Zn and Mg-1Zn was performed.Additionally,Mg-0.4Zn wires together with a variant coated with a copolymer of L-lactide andε-caprolactone were tested in vivo on artificially damaged Wistar rat femurs.Based on the observed Mg-induced osteogenesis,polymer-coated Mg wires with a small addition of Zn are a perspective material for bone-support applications,such as cerclage and fixation wires.