目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组...目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组自制的VMF中,研究其介导的磁场机械力对肿瘤细胞的杀伤效果。结果单纯施加VMF对细胞活力无影响;加入Fe_(3)O_(4)纳米颗粒后,细胞活力随VMF处理时间和Fe_(3)O_(4)纳米颗粒浓度的增加而降低,受损细胞释放的乳酸脱氢酶也随磁场处理时间延长而增加。结论不规则形貌Fe_(3)O_(4)纳米颗粒在VMF下可将机械力转移到肿瘤细胞,破坏细胞结构,导致细胞死亡;所采用的VMF装置结构简单、使用安全、操作方便。所采用的磁性粒子及其杀伤肿瘤细胞的方法,有临床转化潜力。展开更多
The majority of foot deformities are related to arch collapse or instability,especially the longitudinal arch.Although the relationship between the plantar fascia and arch height has been previously investigated,the s...The majority of foot deformities are related to arch collapse or instability,especially the longitudinal arch.Although the relationship between the plantar fascia and arch height has been previously investigated,the stress distribution remains unclear.The aim of this study was to explore the role of the plantar ligaments in foot arch biomechanics.We constructed a geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle from computer tomography images.The model comprised the majority of joints in the foot as well as bone segments,major ligaments,and plantar soft tissue.Release of the plantar fascia and other ligaments was simulated to evaluate the corresponding biomechanical effects on load distribution of the bony and ligamentous structures.These intrinsic ligaments of the foot arch were sectioned to simulate different pathologic situations of injury to the plantar ligaments,and to explore bone segment displacement and stress distribution.The validity of the 3-D FE model was verified by comparing results with experimentally measured data via the displacement and von Mise stress of each bone segment.Plantar fascia release decreased arch height,but did not cause total collapse of the foot arch.The longitudinal foot arch was lost when all the four major plantar ligaments were sectioned simultaneously.Plantar fascia release was compromised by increased strain applied to the plantar ligaments and intensified stress in the midfoot and metatarsal bones.Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted.The 3-D FE model indicated that plantar fascia release may provide relief of focal stress and associated heel pain.However,these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain.The initial strategy for treating plantar fasciitis should be non-operative.展开更多
This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient ...This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient and versatile methods for synthe-sizing high-quality noble metal nanocrystals. The seed-mediated growth method can separate the nucleation and growth stages of metal nanocrystals, and thus provide better control over the size, size distribution, and crystallographic evolution of metal nanocrystals. Because of its high controllability, the seed-mediated growth method is especially promising in providing mechanistic insights into the growth mechanisms of noble metal nanocrystals. In this review, the thermodynamic and kinetic parameters for the nucleation and growth of noble metal nanocrystals are systematically summarized. Mechanistic understanding of these parameters is provided. These studies provide useful guidelines for the rational design and synthesis of novel noble metal nanocrystals with high quality.展开更多
文摘目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组自制的VMF中,研究其介导的磁场机械力对肿瘤细胞的杀伤效果。结果单纯施加VMF对细胞活力无影响;加入Fe_(3)O_(4)纳米颗粒后,细胞活力随VMF处理时间和Fe_(3)O_(4)纳米颗粒浓度的增加而降低,受损细胞释放的乳酸脱氢酶也随磁场处理时间延长而增加。结论不规则形貌Fe_(3)O_(4)纳米颗粒在VMF下可将机械力转移到肿瘤细胞,破坏细胞结构,导致细胞死亡;所采用的VMF装置结构简单、使用安全、操作方便。所采用的磁性粒子及其杀伤肿瘤细胞的方法,有临床转化潜力。
基金supported by the National Natural Science Foundation of China(Grant No. 30801163)
文摘The majority of foot deformities are related to arch collapse or instability,especially the longitudinal arch.Although the relationship between the plantar fascia and arch height has been previously investigated,the stress distribution remains unclear.The aim of this study was to explore the role of the plantar ligaments in foot arch biomechanics.We constructed a geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle from computer tomography images.The model comprised the majority of joints in the foot as well as bone segments,major ligaments,and plantar soft tissue.Release of the plantar fascia and other ligaments was simulated to evaluate the corresponding biomechanical effects on load distribution of the bony and ligamentous structures.These intrinsic ligaments of the foot arch were sectioned to simulate different pathologic situations of injury to the plantar ligaments,and to explore bone segment displacement and stress distribution.The validity of the 3-D FE model was verified by comparing results with experimentally measured data via the displacement and von Mise stress of each bone segment.Plantar fascia release decreased arch height,but did not cause total collapse of the foot arch.The longitudinal foot arch was lost when all the four major plantar ligaments were sectioned simultaneously.Plantar fascia release was compromised by increased strain applied to the plantar ligaments and intensified stress in the midfoot and metatarsal bones.Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted.The 3-D FE model indicated that plantar fascia release may provide relief of focal stress and associated heel pain.However,these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain.The initial strategy for treating plantar fasciitis should be non-operative.
基金supported by the National Natural Science Foundation of China (21175126)
文摘This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal nanocrystals. The seed-mediated growth method has become one of the most efficient and versatile methods for synthe-sizing high-quality noble metal nanocrystals. The seed-mediated growth method can separate the nucleation and growth stages of metal nanocrystals, and thus provide better control over the size, size distribution, and crystallographic evolution of metal nanocrystals. Because of its high controllability, the seed-mediated growth method is especially promising in providing mechanistic insights into the growth mechanisms of noble metal nanocrystals. In this review, the thermodynamic and kinetic parameters for the nucleation and growth of noble metal nanocrystals are systematically summarized. Mechanistic understanding of these parameters is provided. These studies provide useful guidelines for the rational design and synthesis of novel noble metal nanocrystals with high quality.