A combined preoperative red cell distribution width and carcinoembryonic antigen score contribute to prognosis prediction in stage I lung adenocarcinoma.

AIMS: Hematological markers that can be used for prognosis prediction for stage I lung adenocarcinoma (LUAD) are still lacking. Here, we examined the prognostic value of a combination of the red cell distribution width (RDW) and carcinoembryonic antigen (CEA), namely, the RDW-CEA score (RCS), in stage I LUAD. MATERIALS AND METHODS: A retrospective study with 154 patients with stage I LUAD was conducted. Patients were divided into RCS 1 (decreased RDW and CEA), RCS 2 (decreased RDW and increased CEA, increased RDW and decreased CEA), and RCS 3 (increased RDW and CEA) subgroups based on the best optimal cutoff points of RDW and CEA for overall survival (OS). The differences in other clinicopathological parameters among RCS subgroups were calculated. Disease-free survival (DFS) and OS among these groups were determined by Kaplan-Meier analysis, and risk factors for outcome were calculated by a Cox proportional hazards model. RESULTS: Seventy, 65, and 19 patients were assigned to the RCS 1, 2, and 3 subgroups, respectively. Patients ≥ 60 years (P < 0.001), male sex (P = 0.004), T2 stage (P = 0.004), and IB stage (P = 0.006) were more significant in the RCS 2 or 3 subgroups. The RCS had a good area under the curve (AUC) for predicting DFS (AUC = 0.81, P < 0.001) and OS (AUC = 0.93, P < 0.001). The DFS (log-rank = 33.26, P < 0.001) and OS (log-rank = 42.05, P < 0.001) were significantly different among RCS subgroups, with RCS 3 patients displaying the worst survival compared to RCS 1 or 2 patients. RCS 3 was also an independent risk factor for both DFS and OS. CONCLUSIONS: RCS is a useful prognostic indicator in stage I LUAD patients, and RCS 3 patients have poorer survival. However, randomized controlled trials are needed to validate our findings in the future.

Enhanced Mechanical Properties, Corrosion Resistance, Cytocompatibility, Osteogenesis, and Antibacterial Performance of Biodegradable Mg-2Zn-0.5Ca-0.5Sr/Zr Alloys for Bone-Implant Application.

Magnesium (Mg) alloys are widely used in bone fixation and bone repair as biodegradable bone-implant materials. However, their clinical application is limited due to their fast corrosion rate and poor mechanical stability. Here, the development of Mg-2Zn-0.5Ca-0.5Sr (MZCS) and Mg-2Zn-0.5Ca-0.5Zr (MZCZ) alloys with improved mechanical properties, corrosion resistance, cytocompatibility, osteogenesis performance, and antibacterial capability is reported. The hot-extruded (HE) MZCZ sample exhibits the highest ultimate tensile strength of 255.8 ± 2.4 MPa and the highest yield strength of 208.4 ± 2.8 MPa and an elongation of 15.7 ± 0.5%. The HE MZCS sample shows the highest corrosion resistance, with the lowest corrosion current density of 0.2 ± 0.1 µA cm-2 and the lowest corrosion rate of 4 ± 2 µm per year obtained from electrochemical testing, and a degradation rate of 368 µm per year and hydrogen evolution rate of 0.83 ± 0.03 mL cm-2 per day obtained from immersion testing. The MZCZ sample shows the highest cell viability in relation to MC3T3-E1 cells among all alloy extracts, indicating good cytocompatibility except at 25% concentration. Furthermore, the MZCZ alloy shows good antibacterial capability against Staphylococcus aureus.

A biodegradable Zn-5Gd alloy with biomechanical compatibility, cytocompatibility, antibacterial ability, and in vitro and in vivo osteogenesis for orthopedic applications.

Zinc (Zn) and some of its alloys are recognized as promising biodegradable implant materials due to their acceptable biocompatibility, facile processability, and moderate degradation rate. Nevertheless, the limited mechanical properties and stability of as-cast Zn alloys hinder their clinical application. In this work, hot-rolled (HR) and hot-extruded (HE) Zn-5 wt.% gadolinium (Zn-5Gd) samples were prepared by casting and respectively combining with hot rolling and hot extrusion for bone-implant applications. Their microstructure evolution, mechanical properties, corrosion behavior, cytotoxicity, antibacterial ability, and in vitro and in vivo osteogenesis were systematically evaluated. The HR and HE Zn-5Gd exhibited significantly improved mechanical properties compared with those of their pure Zn counterparts and the HR Zn-5Gd showed a unique combination of tensile properties with an ultimate tensile strength of ∼311.6 MPa, yield strength of ∼236.5 MPa, and elongation of ∼40.6%, all of which are greater than the mechanical properties required for bone-implant materials. The HR and HE Zn-5Gd showed higher corrosion resistance than their pure Zn counterpart in Hanks' solution and the HE Zn-5Gd had the lowest corrosion rate of 155 µm/y measured by electrochemical corrosion and degradation rate of 26.9 µm/y measured by immersion testing. The HR and HE Zn-5Gd showed high cytocompatibility toward MC3T3-E1 and MG-63 cells, high antibacterial effects against S. aureus, and better in vitro osteogenic activity than their pure Zn counterparts. Furthermore, the HE Zn-5Gd exhibited better in vivo biocompatibility, osteogenesis, and osteointegration ability than pure Zn and pure Ti. STATEMENT OF SIGNIFICANCE: This work reports the mechanical properties, corrosion behaviors, cytocompatibility, antibacterial ability, in vitro and in vivo osteogenesis of biodegradable Zn-Gd alloy for bone-implant applications. Our findings demonstrate that the hot-rolled (HR) Zn-5Gd showed a unique combination of tensile properties with an ultimate tensile strength of ∼311.6 MPa, yield strength of ∼236.5 MPa, and elongation of ∼40.6%. The HR and HE Zn-5Gd showed higher corrosion resistance than their pure Zn counterpart in Hanks' solution. The HR and HE Zn-5Gd showed high cytocompatibility toward MC3T3-E1 and MG-63 cells, good antibacterial effects against S. aureus, and better in vitro osteogenic activity. Furthermore, the HE Zn-5Gd exhibited better in vivo biocompatibility, osteogenesis, and osteointegration ability than pure Zn and pure Ti.

Biodegradable Zn-5Dy Alloy with Enhanced Osteo/Angio-Genic Activity and Osteointegration Effect via Regulation of SIRT4-Dependent Mitochondrial Function.

Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.

Mechanical properties, corrosion and degradation behaviors, and in vitro cytocompatibility of a biodegradable Zn-5La alloy for bone-implant applications.

Zinc (Zn) and its alloys are used in bone-fixation devices as biodegradable bone-implant materials due to their good biosafety, biological function, biodegradability, and formability. Unfortunately, the clinical application of pure Zn is hindered by its insufficient mechanical properties and slow degradation rate. In this study, a Zn-5 wt.% lanthanum (Zn-5La) alloy with enhanced mechanical properties, suitable degradation rate, and cytocompatibility was developed through La alloying and hot extrusion. The hot-extruded (HE) Zn-5La alloy showed ultimate tensile strength of 286.3 MPa, tensile yield strength of 139.7 MPa, elongation of 35.7%, compressive yield strength of 262.7 MPa, and microhardness of 109.7 HV. The corrosion resistance of the HE Zn-5La in Hanks' and Dulbecco's modified Eagle medium (DMEM) solutions gradually increased with prolonged immersion time. Further, the HE Zn-5La exhibited an electrochemical corrosion rate of 36.7 µm/y in Hanks' solution and 11.4 µm/y in DMEM solution, and a degradation rate of 49.5 µm/y in Hanks' solution and 30.3 µm/y in DMEM solution, after 30 d of immersion. The corrosion resistance of both HE Zn and Zn-5La in DMEM solution was higher than in Hanks' solution. The 25% concentration extract of the HE Zn-5La showed a cell viability of 106.5%, indicating no cytotoxicity toward MG-63 cells. We recommend the HE Zn-5La alloy as a promising candidate material for biodegradable bone-implant applications. STATEMENT OF SIGNIFICANCE: This work reports the mechanical properties, corrosion and degradation behaviors, in vitro cytocompatibility and antibacterial ability of biodegradable Zn-5La alloy for bone-implant applications. Our findings demonstrate that the hot-extruded (HE) Zn-5La alloy showed an ultimate tensile strength of 286.3 MPa, a yield strength of 139.7 MPa, an elongation of 35.7%, compressive yield strength of 262.7 MPa, and microhardness of 109.7 HV. HE Zn-5La exhibited appropriate degradation rates in Hanks' and DMEM solutions. Furthermore, the HE Zn-5La alloy showed good cytocompatibility toward MG-63 and MC3T3-E1 cells and greater antibacterial ability against S. aureus.

Biodegradable Zn-Dy binary alloys with high strength, ductility, cytocompatibility, and antibacterial ability for bone-implant applications.

The unique combination of biodegradability, biocompatibility, and functionality of zinc (Zn)-based alloys makes them highly desirable for a wide range of medical applications. However, a long-standing problem associated with this family of biodegradable alloys in the as-cast state is their limited mechanical strength and slow degradation rate. Here we report the development of Zn-xDy (x = 1, 3, and 5 wt.%) alloys with high strength, ductility, cytocompatibility, antibacterial ability, and appropriate degradation rate for biodegradable bone-implant applications. Our results indicate that the mechanical properties of Zn-xDy alloys were effectively improved with increasing Dy addition and hot-rolling due to the second-phase strengthening. The hot-rolled (HR) Zn-3Dy alloy showed the best combined mechanical performance with an ultimate tensile strength of 270.5 MPa, a yield strength of 214.8 MPa, an elongation of 55.1%, and Brinell hardness of 75.9 HB. The corrosion and degradation rates of HR Zn-xDy alloys in Hanks' solution gradually increased with increasing Dy addition due to the intensification of galvanic corrosion. The HR Zn-3Dy alloy showed high antibacterial ability against S. aureus and cytocompatibility toward MC3T3-E1 cells among all the HR alloys. Overall, the HR Zn-3Dy alloy can be considered a promising biodegradable material for bone implants. STATEMENT OF SIGNIFICANCE: This work reports on Zn-xDy (x = 1, 3, and 5%) alloys fabricated by Dy alloying followed by hot-rolling for biodegradable bone-implant applications. Our findings demonstrate that the hot-rolled (HR) Zn-3Dy alloy showed the best combined mechanical performance with an ultimate tensile strength of 270.5 MPa, a yield strength of 214.8 MPa, an elongation of 55.1%, and Brinell hardness of 75.9 HB. The corrosion and degradation rates of HR Zn-xDy alloys in Hanks' solution gradually increased with increasing Dy addition due to the intensification of galvanic corrosion. Furthermore, the HR Zn-3Dy alloy showed greater antibacterial ability against S. aureus and the best cytocompatibility toward MC3T3-E1 cells among all the HR alloys.

Preoperative carcinoembryonic antigen to body mass index ratio contributes to prognosis prediction in colorectal cancer.

Both carcinoembryonic antigen (CEA) level and body mass index (BMI) are traditional prognostic markers in colorectal cancer (CRC); however, to the best of our knowledge, the value of the CEA to BMI ratio (CBR) has never been addressed. In the present study, 191 patients with CRC treated using radical resection were retrospectively included, and the significance of the CBR in predicting disease-free survival (DFS) or overall survival (OS) rates was calculated. The prognostic efficacy of the CBR in predicting OS was compared with individual CEA and BMI values. The survival differences of the subgroups were calculated by Kaplan-Meier analysis, and corresponding risk factors were then estimated by a Cox proportional hazards model. As a result, 29.84% (57/191) of the patients were assigned to the high CBR group (cut-off, ≥0.28); the CBR had a sensitivity of 56.50 and 68.90%, and a specificity of 80.60 and 80.10% for DFS and OS, respectively. Patients with a high CBR more commonly underwent laparotomy and exhibited advanced T stages, the presence of tumor deposits and advanced Tumor-Node-Metastasis stages (stage II or III). The CBR was more efficient than the CEA or BMI alone in predicting OS. In addition, patients with a high CBR presented with a significantly worse outcome than patients with a low CBR. Finally, the CBR was an independent risk factor for both DFS and OS. In conclusion, the CBR was a more robust prognostic factor in CRC, and patients with a relatively high CBR exhibited poorer survival.

Mechanical, corrosion, nanotribological, and biocompatibility properties of equal channel angular pressed Ti-28Nb-35.4Zr alloys for biomedical applications.

This study systematically investigated the effect of equal channel angular pressing (ECAP) on the microstructure, mechanical, corrosion, nano-tribological properties and biocompatibility of a newly developed ß Ti-28Nb-35.4Zr (hereafter denoted TNZ) alloy. Results indicated that ECAP of the ß TNZ alloy refined its microstructure by forming ultrafine grains without causing stress-induced phase transformation, leading to formation of a single ß phase. The ECAP-processed TNZ alloy exhibited a compressive yield strength of 960 MPa, and high plastic deformation capacity without fracturing under compression loads. Potentiodynamic polarization tests revealed the higher tendency of ECAP-processed TNZ alloys to form passive oxide films on its surface, which exhibited a lower corrosion rate (0.44±0.07 µm/y) in Hanks' balanced salt solution compared to its as-cast counterpart (0.71±0.10 µm/y). Nanotribological testing also revealed higher resistance of the ECAP-processed TNZ alloy to abrasion, wear and scratching, when compared to its as-cast counterpart. Cytocompatibility and cell adhesion assessments of the ECAP-processed TNZ alloys showed a high viability (111%) of human osteoblast-like SaOS2 cells after 7 d of culturing. Moreover, the ECAP-processed TNZ alloy promoted adhesion and spreading of SaOS2 cells, which exhibited growth and proliferation on alloy surfaces. In summary, significantly enhanced mechanical, corrosion, and biological properties of ECAP-processed TNZ alloy advocate its suitability for load-bearing implant applications. STATEMENT OF SIGNIFICANCE: Equal channel angular pressing (ECAP) provides a unique combination of enhanced mechanical and functional properties of materials by optimizing their microstructures and phase transformations. This study investigated the mechanical, nano-tribological, corrosion, and biocompatibility properties of a newly developed ß Ti-28Nb-35.4Zr (TNZ) alloy processed via ECAP. Our findings indicated that ECAP of the ß TNZ alloy refined its microstructure by forming ultrafine grains without causing stress-induced phase transformation. Compared to its as-cast counterpart, ECAP-processed TNZ exhibited significantly enhanced compressive yield strength, plastic deformation capacity, hardness, wear, and corrosion properties. Moreover, in vitro cytocompatibility and cell adhesion studies revealed high cellular viabilities, growth and proliferation of osteoblast-like SaOS2 cells on the ECAP-processed TNZ alloy.

A biodegradable Fe/Zn-3Cu composite with requisite properties for orthopedic applications.

Zinc (Zn)-based metals and alloys are emerging as promising biodegradable implant materials due to their inherent biodegradability and good biocompatibility. However, this class of materials exhibits low mechanical strength and a slow degradation rate, which hinders their clinical application. Here we report the development of a new biodegradable Fe/Zn-3Cu composite fabricated by infiltration casting of a Zn-3Cu alloy into an Fe foam followed by hot-rolling. Our results indicate that the hot-rolled (HR) Fe/Zn-3Cu composite exhibited an α-Zn matrix phase, a secondary CuZn5 phase, and an α-Fe phase. The HR Fe/Zn-3Cu composite exhibited an ultimate tensile strength of 269 MPa, a tensile yield strength of 210 MPa, and an elongation of 27%. The HR Fe/Zn-3Cu composite showed a degradation rate of 228 µm/year after immersion in Hanks' solution for 30 d The diluted extract of the HR Fe/Zn-3Cu composite exhibited a higher cell viability than that of the HR Zn-3Cu alloy in relation to MC3T3-E1 and MG-63 cells. Furthermore, the HR Fe/Zn-3Cu composite showed significantly better antibacterial ability than that of the HR Zn-3Cu alloy in relation to S. aureus. Overall, the HR Fe/Zn-3Cu composite can be anticipated to be a promising biodegradable implant material for bone-fixation applications. STATEMENT OF SIGNIFICANCE: This work reports a new biodegradable Fe/Zn-3Cu composite fabricated by infiltration casting and followed by hot-rolling for biodegradable bone-fixation application. Our findings demonstrated that the hot-rolled (HR) Fe/Zn-3Cu composite exhibited an ultimate tensile strength of 269.1 MPa, a tensile yield strength of 210.3 MPa, and an elongation of 26.7%. HR Fe/Zn-3Cu composite showed a degradation rate of 227.6 µm/a, higher than HR Zn-3Cu alloy after immersion in Hanks' solution for 30 d The diluted extracts of the HR Fe/Zn-3Cu composite exhibited a higher cell viability than HR Zn-3Cu alloy toward MC3T3-E1 cells. Furthermore, the HR Fe/Zn-3Cu composite showed significantly better antibacterial ability than the HR Zn-3Cu alloy toward S. aureus.

A biodegradable in situ Zn-Mg2Ge composite for bone-implant applications.

Zinc (Zn)-based composites have received extensive attention as promising biodegradable materials due to their unique combination of moderate biodegradability, biocompatibility, and functionality. Nevertheless, the low mechanical strength of as-cast Zn-based composites impedes their practical clinical application. Here we reported the mechanical properties, corrosion behavior, wear properties, and cytotoxicity of in situ synthesized biodegradable Zn-xMg2Ge (x = 1, 3, and 5 wt.%) composites for bone-implant applications. The mechanical properties of Zn-xMg2Ge composites were effectively improved by alloying and hot-rolling due to particle reinforcement of the Mg2Ge intermetallic phase and dynamic recrystallization. The hot-rolled (HR) Zn-3Mg2Ge composite exhibited the best mechanical properties, including a yield strength of 162.3 MPa, an ultimate tensile strength of 264.3 MPa, an elongation of 10.9%, and a Brinell hardness of 83.9 HB. With an increase in Mg2Ge content, the corrosion and degradation rates of the HR Zn-xMg2Ge composites gradually increased, while their wear rate decreased and then increased in Hanks' solution. The diluted extract (12.5% concentration) of the HR Zn-3Mg2Ge composite showed the highest cell viability compared to the other HR composites and their as-cast pure Zn counterparts. Overall, the HR Zn-3Mg2Ge composite can be considered a promising biodegradable Zn-based composite for bone-implant applications. STATEMENT OF SIGNIFICANCE: This paper reports the mechanical properties, corrosion behavior, wear properties, and cytotoxicity of in situ synthesized biodegradable Zn-xMg2Ge (x = 1, 3, and 5 wt.%) composites for bone-implant applications. Our findings demonstrated that the mechanical properties of Zn-xMg2Ge composites were effectively improved by alloying and hot-rolling due to Mg2Ge particle reinforcement and dynamic recrystallization. The hot-rolled Zn-3Mg2Ge composite showed superior cytocompatibility, satisfying corrosion and degradation rates, and the best mechanical properties including a yield strength of 162.3 MPa, an ultimate tensile strength of 264.3 MPa, and an elongation of 10.9%.

Impact of gadolinium on mechanical properties, corrosion resistance, and biocompatibility of Zn-1Mg-xGd alloys for biodegradable bone-implant applications.

Zinc (Zn) and its alloys are currently regarded as one of the promising families of biodegradable metals for implant applications owing to their suitable biodegradability and biofunctionality. However, the inadequate mechanical properties of as-cast (AC) pure Zn restricted the practical clinical bone-implant applications due to its coarse grain size and hexagon close-packed crystal structure. Here, the impact of gadolinium (Gd) on the mechanical properties, corrosion resistance, hemolysis percentage, anticoagulant activity, and cytotoxicity of AC and hot-rolled (HR) Zn-1Mg-xGd (x = 0.1, 0.2, and 0.3) (wt.%) alloys were investigated for biodegradable bone-implant applications. Tensile testing showed that the HR Zn-1Mg-0.3Gd alloy exhibited the highest tensile strength of 288.1 MPa, tensile yield strength of 250.9 MPa, and elongation of 13.2%. Electrochemical corrosion and immersion tests revealed that the corrosion rates of both AC and HR specimens increased with increasing Gd content in Hanks' solution, and the HR Zn-1Mg-xGd specimens exhibited higher corrosion rates compared to their AC counterparts. The HR Zn-1Mg-xGd specimens showed an increasing hemolysis percentages and decreasing activated partial thromboplastin time (APTT) values with increasing Gd addition. The alloy extracts of HR samples at ≤ 25% concentration exhibited no cytotoxicity toward MG-63 cells, and the HR Zn-1Mg-0.3Gd alloy displayed the highest cell viability among all three alloy extracts at 12.5% concentration. Overall, the HR Zn-1Mg-0.3Gd can be considered a promising biodegradable implant material for bone-implant materials owing to its high mechanical strength and ductility, suitable degradation rate, and satisfying biocompatibility. STATEMENT OF SIGNIFICANCE: In this work, Zn-1Mg-xGd (x = 0.1, 0.2, and 0.3 wt.%) alloys were developed by alloying with gadolinium (Gd) and hot-rolling, and their mechanical properties, corrosion behavior, hemolysis percentage, anticoagulant activity, and cytotoxicity were investigated for biodegradable implant application. Our findings demonstrated that the hot-rolled Zn-1Mg-0.3Gd alloy exhibit the highest ultimate tensile strength of 288.1 MPa, yield strength of 250.9 MPa, and elongation of 13.2%. Hot-rolled Zn-1Mg-xGd alloys show slowly increasing hemolysis percentages and decreasing activated partial thromboplastin time (APTT) values with increasing Gd addition. Extracts of hot-rolled Zn-1Mg-xGd alloys at a concentration of ≤ 25% show no cytotoxicity towards MG-63 cells, and Zn-1Mg-0.3Gd exhibit good cytocompatibility among all three alloys at a concentration of 12.5%.

Biodegradable Zn-3Mg-0.7Mg2Si composite fabricated by high-pressure solidification for bone implant applications.

Zinc (Zn)-based alloys have been considered potential biodegradable materials for medical applications due to their good biodegradability and biocompatibility. However, the insufficient mechanical properties of pure Zn do not meet the requirements of biodegradable implants. In this study, we have developed a biodegradable Zn-3Mg-0.7Mg2Si composite fabricated by high-pressure solidification. Microstructural characterization revealed that the high-pressure solidified (HPS) composite exhibited uniformly distributed fine MgZn2 granules in an α-Zn matrix. Comprehensive tests indicated that the HPS composite exhibited exceptionally high compression properties including a compressive yield strength of 406.2 MPa, an ultimate compressive strength of 1181.2 MPa, and plastic deformation up to 60% strain without cracking or fracturing. Potentiodynamic polarization tests revealed that the HPS composite showed a corrosion potential of -0.930 V, a corrosion current density of 3.5 µA/cm2, and a corrosion rate of 46.2 µm/y. Immersion tests revealed that the degradation rate of the HPS composite after immersion in Hanks' solution for 1 month and 3 months was 42.8 µm/y and 37.8 µm/y, respectively. Furthermore, an extract of the HPS composite exhibited good cytocompatibility compared with as-cast (AC) pure Zn and an AC composite at a concentration of ≤25%. These results suggest that the HPS Zn-3Mg-0.7Mg2Si composite can be anticipated as a promising biodegradable material for orthopedic applications.

Impact of scandium on mechanical properties, corrosion behavior, friction and wear performance, and cytotoxicity of a ß-type Ti-24Nb-38Zr-2Mo alloy for orthopedic applications.

ß-type titanium (Ti) alloys have been extensively investigated as orthopedic implant materials due to their unique combination of low elastic modulus, high specific strength, corrosion resistance, and biocompatibility. In this study the mechanical properties, corrosion behavior, friction and wear performance, and cytotoxicity of ß-type Ti-24Nb-38Zr-2Mo (TNZM) and Ti-24Nb-38Zr-2Mo-0.1Sc (TNZMS) have been comparatively investigated for orthopedic applications. Cold-rolling (CR) and cold-rolling plus solution-treatment (CR+ST) were performed on the as-cast (AC) alloys and their microstructures and material properties were characterized. The impact of Sc addition on the mechanical and corrosion properties, friction and wear behavior, and in vitro cytocompatibility of the TNZMS alloy was assessed. The CR+ST TNZMS alloy exhibited the best combination of properties among all the alloy samples, with a yield strength of 780 MPa, ultimate strength of 809 MPa, elongation of 19%, Young's modulus of 65.4 GPa, and hardness of 265 HV. Electrochemical testing in Hanks' Solution indicated that the CR+ST TNZMS sample also showed the highest corrosion resistance with a corrosion potential of -0.234 V, corrosion current density of 0.07 µA/cm2, and corrosion rate of 1.2 µm/y. Friction and wear testing revealed that the TNZMS alloy showed higher wear resistance compared to the TNZM alloy and the wear resistance of the different samples was ranked CR > CR+ST > AC. Finally, both the CR+ST TNZM and TNZMS showed no-cytotoxicity towards MG-63 cells and the TNZMS exhibited slightly higher cytocompatibility than the TNZM alloy. STATEMENT OF SIGNIFICANCE: This work reports the ß-type Ti-24Nb-38Zr-2Mo (TNZM) and Ti-24Nb-38Zr-2Mo-0.1Sc (TNZMS) alloys fabricated by as-cast (AC), cold-rolling (CR), and cold-rolling plus solution-treatment (CR+ST) for potential orthopedic applications. The experimental results showed that the TNZMS alloy exhibited significantly enhanced mechanical, wear, and corrosion properties than those of TNZM alloy; and the CR+ST TNZMS possess a unique combination of the best mechanical and corrosion properties including a yield strength of 780 MPa, ultimate strength of 809 MPa, elongation of 19%, Young's modulus of 65.4 GPa, and corrosion rate of 1.2 µm/y in Hanks' Solution. Both the CR+ST TNZM and TNZMS alloys exhibited non-cytotoxicity towards MG-63 cells and TNZMS showed a higher cytocompatibility than that of TNZM.

Effect of Anodized TiO2-Nb2O5-ZrO2 Nanotubes with Different Nanoscale Dimensions on the Biocompatibility of a Ti35Zr28Nb Alloy.

Some important factors in the design of biomaterials are surface characteristics such as surface chemistry and topography, which significantly influence the relationship between the biomaterial and host cells. Therefore, nanotubular oxide layers have received substantial attention for biomedical applications due to their potential benefits in the improvement of the biocompatibility of the substrate. In this study, a nanotubular layer of titania-niobium pentoxide-zirconia (TiO2-Nb2O5-ZrO2) was developed via anodization on a ß-type Ti35Zr28Nb alloy surface with enhanced biocompatibility. Scanning electron microscopy (SEM) and surface profilometry analysis of the anodized nanotubes indicated that the inner diameter (Di) and wall thicknesses (Wt) increased with an increase in the water content of electrolyte and the applied voltage during anodization, while the nanotube length (Ln) increased with increasing the anodization time. TiO2-Nb2O5-ZrO2 nanotubes with different Di, Wt, and Ln showed different surface roughnesses (Ra) and surface energies (γ), which affected the biocompatibility of the base alloy. MTS assay results showed that the TiO2-Nb2O5-ZrO2 nanotubes with the largest inner diameter (Di) of 75.9 nm exhibited the highest cell viability of 108.55% due to the high γ of the surface, which led to high adsorption of proteins on the top surface of the nanotubes. The second highest cell viability was observed on the nanotubular surface with Di of 33.3 nm, which is believed to result from its high γ as well as the optimum spacing between nanotubes. Ra did not appear to be clearly linked to cellular response; however, there may exist a threshold value of surface energy of ∼70 mJ/m2, below which the cell response is less sensitive and above which the cell viability increases with increasing γ. This indicates that the TiO2-Nb2O5-ZrO2 nanotubes provided a suitable environment for enhanced attachment and growth of osteoblast-like cells as compared to the bare Ti35Zr28Nb alloy surface.

Clear cell tumor of the lung could be aggressive: a case report and review of the literature.

BACKGROUND: Clear cell tumors of the lung (CCTLs) are rare and mostly benign pulmonary neoplasms arising from perivascular epithelioid cells. Only approximately 100 cases have been reported, and half of them were in China. Limited details about CCTLs often cause diagnostic or therapeutic problems. CASE PRESENTATION: We describe a case of a 28-year-old woman with multiple gradually replicating and enlarging nodules in the left lower lobe. The patient underwent fine-needle aspiration biopsy and was diagnosed with CCTL. A left lower lobectomy and mediastinal lymph node dissection were performed. The gradual changes in size (1.4 cm to 2.8 cm) and quantity (10 to 49) of the CCTLs in this case were the biggest differences from previously reported cases. CONCLUSIONS: CCTLs are very uncommon and mostly benign PEComatous tumors with no specific morphologic features. We present a case of CCTL with multiplicity and rapid growth, which may indicate its aggressive nature. The accumulation of similar cases will help clarify the exact nature and improve our understanding of the disease.

Mechanical, corrosion, and biocompatibility properties of Mg-Zr-Sr-Sc alloys for biodegradable implant applications.

Magnesium (Mg) and its alloys are considered promising biodegradable implant materials because of their strength and natural degradation in the human body. However, the high corrosion rate of pure Mg in the physiological environment leads to rapid degradation before adequate bone healing. This mismatch between bone healing and the degradation of Mg implants supports the development of new Mg alloys with the addition of other suitable alloying elements in order to achieve simultaneously high corrosion resistance and desirable mechanical properties. This study systematically investigates the microstructure, mechanical properties, corrosion behavior, and biocompatibility of Mg-based alloys with the addition of different concentrations of scandium (Sc), i.e., Mg-0.6Zr-0.5Sr-xSc (x = 0.5, 1, 2, 3 wt.%). Results indicated that high concentration of Sc in strontium (Sr)-containing Mg alloys can alter their microstructures by suppressing the intermetallic phases along the grain boundaries and improve the corrosion resistance by forming chemically stable Sc oxide layers on the surfaces of the Mg alloys. Cytotoxicity assessment revealed that the Sc containing Mg alloys did not significantly alter the viability of human osteoblast-like SaOS2 cells. This study highlights the advantages of using Sc as an alloying element to simultaneously tune Mg alloys with higher strength and slower degradation. STATEMENT OF SIGNIFICANCE: Rare earth elements such as scandium (Sc) with both a high solid-solubility and strong affinity towards oxygen can improve the mechanical and corrosion properties of magnesium (Mg) alloys. However, the feasibility of Sc-containing Mg alloys as biodegradable implant materials is scarcely reported. This study investigates the effects of different Sc concentrations on the mechanical, corrosion, and biocompatibility properties of Mg-Zr-Sr-Sc alloys. Our findings indicated that the addition of Sc significantly improves the mechanical and corrosion properties of Mg-Zr-Sr alloys. Moreover, in vitro cytotoxicity assessment of the Mg-Zr-Sr-Sc alloys did not show any adverse effects on the viability of osteoblast-like cells.

Degradation behavior, cytotoxicity, hemolysis, and antibacterial properties of electro-deposited Zn-Cu metal foams as potential biodegradable bone implants.

Zinc (Zn) alloys have attracted much attention for biomedical applications due to their biodegradability, biocompatibility, and biological functionalities. Zn alloy foams have high potential to be used as regenerative medical implants by virtue of their porous structure, which allows new bone tissue ingrowth, their low elastic modulus approximating that of natural bone, and their biodegradation, which eliminates the need for follow-up surgery to remove the implants after bone tissue healing. In this context, a biodegradable Zn-Cu foam was fabricated by electrochemical deposition on a foamed Cu template and given a subsequent diffusion heat treatment. The microstructure, mechanical properties, degradation behavior, toxicity, hemolysis percentages, and antibacterial effects of the Zn-Cu foams were assessed for biomedical applications. The Zn-Cu foams exhibited a yield strength of ~12.1 MPa, a plateau strength of 16.8 MPa, and a strain over 50% under compression tests. The corrosion rate of the Zn-Cu foams measured by electrochemical polarization testing was 0.18 mm/y. The Zn-Cu foams showed good blood compatibility with a hemolysis percentage of less than 5%. Cytotoxicity assessment indicated that a 100% concentration of the Zn-Cu foam extract showed clear cytotoxicity against MC3T3-E1 osteoblast cells, but a 12.5% concentration of the extract showed > 90% cell viability. Moreover, the Zn-Cu foams showed good antibacterial effects. STATEMENT OF SIGNIFICANCE: This work reportsa biodegradable Zn-Cu foam with high mechanical strength and ductility, suitable degradation rate, good antibacterial capacity, and good hemolysis property and biocompatibility. The Zn-Cu foam exhibited a yield strength of ~12.1 MPa, a plateau strength of 16.8 MPa, and a strain over 50% under compression tests. The corrosion rate of the Zn-Cu foam measured by electrochemical polarization testing was 0.18 mm/y in Hanks' Solutions. The Zn-Cu foam showed good blood compatibility with a hemolysis percentage of less than 5%. Cytotoxicity assessment indicated that a 12.5% concentration of the foam extract showed > 90% cell viability. Moreover, the Zn-Cu foam showed good antibacterial effects against S. aureus.

Biodegradable ternary Zn-3Ge-0.5X (X=Cu, Mg, and Fe) alloys for orthopedic applications.

Biodegradable zinc (Zn) and its alloys have great potential to be used for orthopedic applications due to their suitable degradation rate and good biocompatibility. However, pure Zn has insufficient mechanical properties, such as low strength and hardness, and poor plasticity, which limits its clinical applications. Here, we report on a new series of ternary Zn-3Ge-0.5X (X=Cu, Mg, and Fe) alloys aiming to achieve good corrosion resistance and biocompatibility, and enhanced mechanical properties via micro-alloying with copper (Cu), magnesium (Mg), and iron (Fe). Hot-rolling has also been applied to the new ternary alloys to further enhance their mechanical properties. Mechanical testing results indicate that both the strength and hardness of hot-rolled Zn-3Ge are significantly improved with micro-alloying of Cu, Mg, and Fe; of which the hot-rolled Zn-3Ge-0.5Mg exhibits the highest ultimate tensile strength of 253.4 MPa and yield strength of 208.5 MPa among all the alloys, 25.9% and 44.7% higher than those of the hot-rolled Zn-3Ge. The degradation rate of the as-cast alloys is lower than that of the hot-rolled alloys in Hanks' solution for 1 month and the hot-rolled Zn-3Ge-0.5Mg alloy exhibits the highest degradation rate of 0.075 mm/y. CCK-8 assay using MG-63 cells indicates that the diluted extracts of Zn-3Ge-0.5X (X=Cu, Mg, and Fe) alloys with concentrations of 12.5% and 25% exhibit no or slight cytotoxicity, and the diluted extracts of Zn-3Ge-0.5Cu alloys show high cell viability of over 100%, showing the best cytocompatibility.

Development of biodegradable Zn-1Mg-0.1RE (RE = Er, Dy, and Ho) alloys for biomedical applications.

Zinc (Zn) and its alloys are receiving great attention as promising biodegradable materials due to their suitable corrosion resistance, good biocompatibility, and highly desirable biofunctionality. Nevertheless, the low mechanical strength of pure Zn impedes its practical clinical application and there have been calls for further research into the Zn alloys and thermomechanical processes to enhance their mechanical properties and biocompatibility. Here, we report on the alloying efficacy of rare earth elements (REEs) including erbium (Er), dysprosium (Dy), and holmium (Ho) on the microstructure, mechanical properties, corrosion and wear behavior, and in vitro biological properties of Zn-1Mg-0.1RE alloys. Microstructural characterization revealed that the addition of 0.1 wt.% REEs had a significant refining effect on the grain size of the α-Zn matrix and the second phases of the alloys. Alloying of the REEs and hot-rolling effectively improved the mechanical properties due to both precipitation strengthening of the second phases of ErZn5, DyZn5, and Ho2Zn17 and grain-refinement strengthening. The highest ultimate tensile strength of 259.4 MPa and yield strength of 234.8 MPa with elongation of 16.8% were achieved in the hot-rolled Zn-1Mg-0.1Ho. Alloying of REEs also improved the wear and corrosion resistance, and slowed down the degradation rate in Hanks' solution. Zn-1Mg-0.1Er showed the highest cytocompatibility of MC3T3-E1 cells cultured directly on the alloy surface and of MG-63 cells cultured in the alloy extract. Zn-1Mg-0.1Dy showed the best anticoagulant property among all the alloys. Overall, these Zn-1Mg-0.1RE (Er, Dy, and Ho) alloys can be considered promising biodegradable metallic materials for orthopedic applications.

A biodegradable Zn-1Cu-0.1Ti alloy with antibacterial properties for orthopedic applications.

Zinc (Zn) alloys are receiving increasing attention in the field of biodegradable implant materials due to their unique combination of suitable biodegradability and good biological functionalities. However, the currently existing industrial Zn alloys are not necessarily biocompatible, nor sufficiently mechanically strong and wear-resistant. In this study, a Zn-1Cu-0.1Ti alloy is developed with enhanced mechanical strength, corrosion wear property, biocompatibility, and antibacterial ability for biodegradable implant material applications. HR and HR + CR were performed on the as-cast alloy and its microstructure, mechanical properties, frictional and wear behaviors, corrosion resistance, in vitro cytocompatibility, and antibacterial ability were systematically assessed. The microstructures of the Zn-1Cu-0.1Ti alloy after different deformation conditions included a η-Zn phase, a ε-CuZn5 phase, and an intermetallic phase of TiZn16. The HR+CR sample of Zn-1Cu-0.1Ti exhibited a yield strength of 204.2 MPa, an ultimate tensile strength of 249.9 MPa, and an elongation of 75.2%; significantly higher than those of the HR alloy and the AC alloy. The degradation rate in Hanks' solution was 0.029 mm/y for the AC alloy, 0.032 mm/y for the HR+CR alloy, and 0.034 mm/y for the HR alloy. The HR Zn-1Cu-0.1Ti alloy showed the best wear resistance, followed by the AC alloy and the alloy after HR + CR. The extract of the AC Zn-1Cu-0.1Ti alloy showed over 80% cell viability with MC3T3-E1 pre-osteoblast and MG-63 osteosarcoma cells at a concentration of ≤ 25%. The as-cast Zn-1Cu-0.1Ti alloy showed good blood compatibility and antibacterial ability. STATEMENT OF SIGNIFICANCE: This work repots a Zn-1Cu-0.1Ti alloy with enhanced mechanical strength, corrosion wear property, biocompatibility, and antibacterial ability for biodegradable implant applications. Our findings showed that Zn-1Cu-0.1Ti after hot-rolling plus cold-rolling exhibited a yield strength of 204.2 MPa, an ultimate tensile strength of 249.9 MPa, an elongation of 75.2%, and a degradation rate of 0.032 mm/y in Hanks' Solution. The hot-rolled Zn-1Cu-0.1Ti showed the best wear resistance. The extract of the as-cast alloy at a concentration of ≤ 25% showed over 80% cell viability with MC3T3-E1 and MG-63 cells. The Zn-1Cu-0.1Ti alloy showed good hemocompatibility and antibacterial ability.