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91.
JUAN M. MARTI LV Cert SAO MVM MRCVS SIMON C. ROE BVSc MS PhD Diplomate ACVS 《Veterinary surgery : VS》1998,27(5):423-428
Objective —To compare the insertional characteristics of external fixator pins with hollow ground (HG), modified HG, and trocar (T) points.
Study Design —An acute, in vitro biomechanical evaluation.
Sample Population—Thirteen radii from canine cadavers.
Methods —A total of 16 T-tipped and 16 HG-tipped pins were inserted into 8 canine radii. Ten pins of each modification of the HG tip (length of the cutting edge reduced by 0.127 mm and 0.254 mm, respectively) were inserted into another five radii. All pins were inserted with low-speed power drilling and 80 N drilling load. Differences between peak tip temperature, drilling energy, and pullout force were determined for each pin type at both diaphyseal and metaphyseal locations.
Results —HG-tipped pins showed a 40% lower tip temperature in diaphyseal bone, a 25% reduction in drilling energy in diaphyseal bone, and a reduction of pullout force in both diaphyseal (65%) and metaphyseal (50%) bone compared with T-tipped pins. HG 0.254-mm pins generated higher tip temperatures and had greater pullout than HG pins in diaphyseal bone.
Conclusions —The HG tip was a more efficient design; however, the reduction in pullout force suggests that, because a better hole was drilled, radial preload is reduced. Reduction of the cutting edge by 0.254 mm increased the pullout force but also increased the temperatures.
Clinical Relevance —Thermal and microstructural damage are reduced by the HG tip, but pin-bone interface stability is also compromised. The use of a tip with 0.254 mm reduction in the cutting edge may optimize the biological and mechanical factors at the pin-bone interface. 相似文献
Study Design —An acute, in vitro biomechanical evaluation.
Sample Population—Thirteen radii from canine cadavers.
Methods —A total of 16 T-tipped and 16 HG-tipped pins were inserted into 8 canine radii. Ten pins of each modification of the HG tip (length of the cutting edge reduced by 0.127 mm and 0.254 mm, respectively) were inserted into another five radii. All pins were inserted with low-speed power drilling and 80 N drilling load. Differences between peak tip temperature, drilling energy, and pullout force were determined for each pin type at both diaphyseal and metaphyseal locations.
Results —HG-tipped pins showed a 40% lower tip temperature in diaphyseal bone, a 25% reduction in drilling energy in diaphyseal bone, and a reduction of pullout force in both diaphyseal (65%) and metaphyseal (50%) bone compared with T-tipped pins. HG 0.254-mm pins generated higher tip temperatures and had greater pullout than HG pins in diaphyseal bone.
Conclusions —The HG tip was a more efficient design; however, the reduction in pullout force suggests that, because a better hole was drilled, radial preload is reduced. Reduction of the cutting edge by 0.254 mm increased the pullout force but also increased the temperatures.
Clinical Relevance —Thermal and microstructural damage are reduced by the HG tip, but pin-bone interface stability is also compromised. The use of a tip with 0.254 mm reduction in the cutting edge may optimize the biological and mechanical factors at the pin-bone interface. 相似文献
92.
文章针对如何致力于提高高中物理教学质量这一问题进行研究探讨,并制定改善这一问题的相关措施,从而来对物理教育这一事业做出贡献,希望它能够有更好的发展. 相似文献
93.
94.
湛江市甘蔗良种场引进甘蔗新品种,优选出优良株系,暂命名为湛引8号。2006年以来在湛江通过试种,证明该品种具有高产、稳产、早熟、高糖等特点,适合湛江蔗区种植。本文主要介绍该品种在当地的种植表现及配套栽培技术。 相似文献
95.
樟树的特征特性及栽培技术 总被引:4,自引:0,他引:4
<正>樟树别名香樟、樟木,是中国的珍贵用材树种之一。樟树四季常绿,树形美观,是城市绿化的优良树种。樟树为常绿乔木,树冠卵形;树皮灰褐色,纵裂;叶互生,卵状椭圆形,薄革质,离基三出脉;圆锥花絮腋生于新枝,花被淡黄绿色,6裂;核果球形,熟时紫黑色,果托盘状。花期5月;果实9~11月成熟。 相似文献
97.
98.
利用L9(34)正交设计,研究了4种不同因素:IBA、6-BA、蔗糖含量及活性炭含量配合使用对铺地百里香增殖快繁培养的影响.经直观分析、方差分析和多重比较进行综合评价,筛选出最佳铺地百里香增殖培养基为MS IBA 1.0 mg/L 6-BA 0.1 mg/L 蔗糖20%. 相似文献
99.
100.