Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechan...Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechanical properties with natural bone.They can be gradually degraded and absorbed so as to avoid the second surgery for implants removal after the tissues are healed completely.In addition,they are also able to prevent the stress shielding effect in human body environment because of the density,elastic modulus and yield strength of magnesium closer to the bone.Unfortunately,the high corrosion rate which causes early mechanical failure of the implants in physiological environment limits the widespread use of magnesium alloys for clinical application in biology.And the high corrosion process usually causes huge hydrogen evolution and alkalinization,resulting in problems against the implants as well as the surrounding tissues.In order to enhance the corrosion resistance of magnesium alloys,in this study,the ZEK100 magnesium alloy was pre-deformed with a highpressure torsion(HPT)process and then fabricated hydroxyapatite(HA)coatings with different contents of Mg(OH)2 nanopowder via hydrothermal method.The specimens were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).At the same time,prior and after the HPT procedure,the metallography,microhardness and tensile tests of specimens were characterized.Meanwhile,the corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy(EIS)and hydrogen evolution tests.And the interface bonding strength of the HA coating on the magnesium alloy substrate was evaluated by a tape adhesion test/scratch test.Results showed that HPT processing refined the grain size and introduced a great number of twins,resulting in the enhancement of microhardness and Young’s modulus of ZEK100 magnesium alloy,but hardness values at the edge were higher than those at the center due to the uneven shear strain.At the same conditions,the HA coating on HPT-ZEK was denser,thicker than that on ZEK sample and the crystal sizes of HA were smaller on HPT-ZEK.These were attributed to fine,uniform distributed secondary phases and lots of fine grains,twins,grain boundaries in HPT-ZEK substrates which can provide more nucleation sites for the HA crystal.In terms of the amount of Mg(OH)2 nanopowder,Mg(OH)2 nanopowder significantly influenced the microstructure and thickness of the HA coating.And at a 0.3 mg/mL content of Mg(OH)2 nanopowder,there was the densest,thickest HA coating on magnesium alloys,and the crystal size of HA was minimum.Specifically,the HA coating thickness on ZEK-03(0.3 mg/mL Mg(OH)2 nanopowder)was 1.8 times of that on ZEK-00(0 mg/mL Mg(OH)2 nanopowder),while the HA coating thickness on HPT-03 was 2.6 times of that on ZEK-00.And the adhesion strength of HA coating on HPT-03 substrate was better than that on ZEK-03.In addition,HPT technology and surface modification by HA coating simultaneously increased the corrosion resistance of ZEK100 magnesium alloy and the corrosion of HPT-ZEK samples occurred in a more uniform manner,while it was pitting on the surface of ZEK100 magnesium alloy.Therefore,there was the best corrosion resistance on HPT-03 sample,which could promote the application of magnesium alloys in biomedical fields.展开更多
目的研究肿瘤经外周穿刺中心静脉导管置入术(peripherally inserted central catheter,PICC)置管处患者继发皮肤损害的菌群耐药性及复方黄柏液涂剂治疗对导管相关并发症和炎性反应的影响。方法本研究采用回顾性研究,主要以2020年12月至2...目的研究肿瘤经外周穿刺中心静脉导管置入术(peripherally inserted central catheter,PICC)置管处患者继发皮肤损害的菌群耐药性及复方黄柏液涂剂治疗对导管相关并发症和炎性反应的影响。方法本研究采用回顾性研究,主要以2020年12月至2021年12月海安市人民医院收治的40例PICC置管处继发皮肤损害患者作为研究对象,根据患者治疗手段的差异分为两组,各20例。对照组根据药敏情况采取相应的抗生素治疗,观察组联合采用复方黄柏液涂剂。分析肿瘤患者PICC置管处继发皮肤损害菌群的分布,研究两组患者的导管相关并发症及炎性反应之间的差异。结果PICC置管处继发皮肤损害病原菌感染主要以革兰阳性菌和革兰阴性菌为主,真菌感染较少。凝固酶阴性葡萄球菌、肺炎链球菌、金黄色葡萄球菌主要对青霉素、苯唑西林及氨苄西林耐药。鲍曼不动杆菌、阴沟肠杆菌、大肠埃希菌主要通过对亚胺培南以及阿米卡星耐药。观察组患者发生导管相关血流感染、穿刺口感染、导管移位和脱出、管端细菌定植情况低于对照组(P<0.05)。两组患者经过治疗后,白细胞介素-1β、肿瘤坏死因子-α和白细胞介素-6水平均显著下降,且观察组低于对照组(P<0.05)。结论肿瘤患者PICC置管处继发皮肤损害菌群主要以革兰氏阴性菌为主,对PICC置管处继发皮肤损害患者的治疗中采取复方黄柏液涂剂,患者的治疗效果显著,炎性反应显著下降。展开更多
目的分析高耐药性肺癌患者外周静脉置入中心静脉导管(peripherally inserted central catheter,PICC)相关性深静脉血栓形成的危险因素。方法回顾性分析2015年5月至2017年5月本院收治的156例行PICC化疗的高耐药性肺癌患者的临床资料,分...目的分析高耐药性肺癌患者外周静脉置入中心静脉导管(peripherally inserted central catheter,PICC)相关性深静脉血栓形成的危险因素。方法回顾性分析2015年5月至2017年5月本院收治的156例行PICC化疗的高耐药性肺癌患者的临床资料,分析高耐药性肺癌患者PICC置管后深静脉血栓形成的危险因素。结果 156例高耐药性肺癌患者中,发生PICC相关性深静脉血栓18例,发生率为11.54%。多因素Logistic回归分析显示:女性、头静脉置管、PICC留管时间>1个月、纤维蛋白原水平>4 g/L、D-二聚体水平>0.5 mg/ml及腺癌是高耐药性肺癌患者PICC相关性深静脉血栓形成的独立危险因素(P<0.05)。结论性别、穿刺静脉、纤维蛋白原、D-二聚体、留管时间以及病理类型为高耐药性肺癌患者PICC相关性深静脉血栓形成的危险因素,临床需予以重点关注和及早预防,以降低PICC相关性深静脉血栓形成的发生风险。展开更多
The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kin...The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kind of roller material, the high-vanadium alloy steel （HVAS）, was investigated. The results showed that the as-cast microstructures of the HVAS roller contained martensite, residual austenite, and alloy carbides. The HVAS sample quenched at 1,080 ℃ had a high hardness, and it had much higher compressive strength and abrasive wear resistance after tempering at 560 ℃ for 30 rain. The mechanical properties of the HVAS are more sufficient than the existing roller materials, which are feasible for larger machine design.展开更多
The Ti-45Nb (mass%) alloy’s corrosive and biocompatible response in simulated physiological conditions was investigated before and after its additional high-pressure torsion (HPT) and laser irradiation processing. Th...The Ti-45Nb (mass%) alloy’s corrosive and biocompatible response in simulated physiological conditions was investigated before and after its additional high-pressure torsion (HPT) and laser irradiation processing. The grain size reduction from 2.76 µm to ~ 200 nm and the appearance of laser-induced morphologically altered and highly oxidized surface led to the significant improvement of alloy corrosion resistance and cell–implant interaction. Moreover, an additional increase of the laser pulse energy from 5 to 15 mJ during the alloy irradiation in the air led to an increase in the surface oxygen content from 13.64 to 23.89% accompanied by an increase of excellent cell viability from 127.18 to 134.42%. As a result of the controlled alloy microstructural and surface modifications, the formation of protective bi-modal mixed Ti- and Nb-oxide external scale was enabled. The presence of this surface oxide scale enhanced the alloy’s resistance to corrosion deterioration and simultaneously boosted cell viability and proliferation.展开更多
基金sponsored by the National Natural Science Foundation of China ( 51571150,11572222)Tianjin Natural Science Foundation ( 14JCYBJC16900)
文摘Recently,magnesium and its alloys have attracted more and more attention as promising implant materials due to their excellent properties such as good biocompatibility,biodegradation,non-toxicity and comparable mechanical properties with natural bone.They can be gradually degraded and absorbed so as to avoid the second surgery for implants removal after the tissues are healed completely.In addition,they are also able to prevent the stress shielding effect in human body environment because of the density,elastic modulus and yield strength of magnesium closer to the bone.Unfortunately,the high corrosion rate which causes early mechanical failure of the implants in physiological environment limits the widespread use of magnesium alloys for clinical application in biology.And the high corrosion process usually causes huge hydrogen evolution and alkalinization,resulting in problems against the implants as well as the surrounding tissues.In order to enhance the corrosion resistance of magnesium alloys,in this study,the ZEK100 magnesium alloy was pre-deformed with a highpressure torsion(HPT)process and then fabricated hydroxyapatite(HA)coatings with different contents of Mg(OH)2 nanopowder via hydrothermal method.The specimens were characterized by scanning electron microscope(SEM)and X-ray diffraction(XRD).At the same time,prior and after the HPT procedure,the metallography,microhardness and tensile tests of specimens were characterized.Meanwhile,the corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy(EIS)and hydrogen evolution tests.And the interface bonding strength of the HA coating on the magnesium alloy substrate was evaluated by a tape adhesion test/scratch test.Results showed that HPT processing refined the grain size and introduced a great number of twins,resulting in the enhancement of microhardness and Young’s modulus of ZEK100 magnesium alloy,but hardness values at the edge were higher than those at the center due to the uneven shear strain.At the same conditions,the HA coating on HPT-ZEK was denser,thicker than that on ZEK sample and the crystal sizes of HA were smaller on HPT-ZEK.These were attributed to fine,uniform distributed secondary phases and lots of fine grains,twins,grain boundaries in HPT-ZEK substrates which can provide more nucleation sites for the HA crystal.In terms of the amount of Mg(OH)2 nanopowder,Mg(OH)2 nanopowder significantly influenced the microstructure and thickness of the HA coating.And at a 0.3 mg/mL content of Mg(OH)2 nanopowder,there was the densest,thickest HA coating on magnesium alloys,and the crystal size of HA was minimum.Specifically,the HA coating thickness on ZEK-03(0.3 mg/mL Mg(OH)2 nanopowder)was 1.8 times of that on ZEK-00(0 mg/mL Mg(OH)2 nanopowder),while the HA coating thickness on HPT-03 was 2.6 times of that on ZEK-00.And the adhesion strength of HA coating on HPT-03 substrate was better than that on ZEK-03.In addition,HPT technology and surface modification by HA coating simultaneously increased the corrosion resistance of ZEK100 magnesium alloy and the corrosion of HPT-ZEK samples occurred in a more uniform manner,while it was pitting on the surface of ZEK100 magnesium alloy.Therefore,there was the best corrosion resistance on HPT-03 sample,which could promote the application of magnesium alloys in biomedical fields.
文摘目的研究肿瘤经外周穿刺中心静脉导管置入术(peripherally inserted central catheter,PICC)置管处患者继发皮肤损害的菌群耐药性及复方黄柏液涂剂治疗对导管相关并发症和炎性反应的影响。方法本研究采用回顾性研究,主要以2020年12月至2021年12月海安市人民医院收治的40例PICC置管处继发皮肤损害患者作为研究对象,根据患者治疗手段的差异分为两组,各20例。对照组根据药敏情况采取相应的抗生素治疗,观察组联合采用复方黄柏液涂剂。分析肿瘤患者PICC置管处继发皮肤损害菌群的分布,研究两组患者的导管相关并发症及炎性反应之间的差异。结果PICC置管处继发皮肤损害病原菌感染主要以革兰阳性菌和革兰阴性菌为主,真菌感染较少。凝固酶阴性葡萄球菌、肺炎链球菌、金黄色葡萄球菌主要对青霉素、苯唑西林及氨苄西林耐药。鲍曼不动杆菌、阴沟肠杆菌、大肠埃希菌主要通过对亚胺培南以及阿米卡星耐药。观察组患者发生导管相关血流感染、穿刺口感染、导管移位和脱出、管端细菌定植情况低于对照组(P<0.05)。两组患者经过治疗后,白细胞介素-1β、肿瘤坏死因子-α和白细胞介素-6水平均显著下降,且观察组低于对照组(P<0.05)。结论肿瘤患者PICC置管处继发皮肤损害菌群主要以革兰氏阴性菌为主,对PICC置管处继发皮肤损害患者的治疗中采取复方黄柏液涂剂,患者的治疗效果显著,炎性反应显著下降。
基金supported by the National High Technology Research and Development Program (No. 2012AA03A508)Project of Science and Technology Plan of Shenyang City (No. F12-027-2-00)Project of Science and Technology Plan of Liaoning Province (No. LNSBQ4-2010921055)
文摘The roller is one of the main parts of a high-pressure grinding roller, which is a type of highly efficient ore crushing equipment. Its working life is strongly affected by the materials used. In this paper, a new kind of roller material, the high-vanadium alloy steel （HVAS）, was investigated. The results showed that the as-cast microstructures of the HVAS roller contained martensite, residual austenite, and alloy carbides. The HVAS sample quenched at 1,080 ℃ had a high hardness, and it had much higher compressive strength and abrasive wear resistance after tempering at 560 ℃ for 30 rain. The mechanical properties of the HVAS are more sufficient than the existing roller materials, which are feasible for larger machine design.
基金supported by the Ministry of Science,Technological Development and Innovation of the Republic of Serbia through Contract Nos.451-03-47/2023-01/200017 and 451-03-66/2024-03/200017 and the Ph.D.fellowship of Slađana Laketić.
文摘The Ti-45Nb (mass%) alloy’s corrosive and biocompatible response in simulated physiological conditions was investigated before and after its additional high-pressure torsion (HPT) and laser irradiation processing. The grain size reduction from 2.76 µm to ~ 200 nm and the appearance of laser-induced morphologically altered and highly oxidized surface led to the significant improvement of alloy corrosion resistance and cell–implant interaction. Moreover, an additional increase of the laser pulse energy from 5 to 15 mJ during the alloy irradiation in the air led to an increase in the surface oxygen content from 13.64 to 23.89% accompanied by an increase of excellent cell viability from 127.18 to 134.42%. As a result of the controlled alloy microstructural and surface modifications, the formation of protective bi-modal mixed Ti- and Nb-oxide external scale was enabled. The presence of this surface oxide scale enhanced the alloy’s resistance to corrosion deterioration and simultaneously boosted cell viability and proliferation.
