Abstract: In medicine, objects that need to be removed later-such as stents-are commonly placed i... more Abstract: In medicine, objects that need to be removed later-such as stents-are commonly placed in patients, with the time of removal dependent on progress of the patient. In these cases biodegradable materials that last for a specific time may not be suitable. We propose a new class of nanostructured materials that can hold their form as long as wanted, Triggered, Nanostructured Biodegradables (TNBs), that can be disintegrated to micro-or nanoscaled components when externally triggered on command to do so.
Purpose. According to the conventional arch model of the pelvis, stability of the sacroiliac join... more Purpose. According to the conventional arch model of the pelvis, stability of the sacroiliac joints may requires a predominance of form and force closure mechanisms: the greater the vertical shear force at the sacroiliac joints, the greater the reliance on self-bracing by horizontal or obliquely oriented muscles (such as the internal oblique). But what happens to the arch model when a person stands on one leg? In such cases, the pelvis no longer has imposts, leaving both the arch, and the arch model theory, without support. Do lumbopelvic muscle activation patterns in one-legged stances under load suggest compatibility with a different model? This study compares lumbopelvic muscle activation patterns in two-legged and one-legged stances in response to four levels of graded trunk loading in order to further our understanding the stabilization of the sacroiliac joints.
The scapula is a sesamoid bone. Stephen Michael Levin. Potomac Back Center, 8608 Dixie Place, Mcl... more The scapula is a sesamoid bone. Stephen Michael Levin. Potomac Back Center, 8608 Dixie Place, Mclean, VA 22102, USA. Available online 26 January 2005. Article Outline. References. Gupta and van der Helm (2004) use finite ...
The structure-function relationship of anulus fibrosus of nondegenerate lumbar intervertebral dis... more The structure-function relationship of anulus fibrosus of nondegenerate lumbar intervertebral discs was investigated. The tensile properties and biochemical composition of single lamella specimens from human anulus fibrosus and their variations with anatomic region were determined. Regional differences in composition and ultrastructure suggest differences in tensile properties. Single lamella specimens were isolated from the anulus, equilibrated in 0.15 mol/L NaCl and tested in uniaxial tension using a slow strain-rate protocol. Adjacent specimens were used to determine biochemical composition (including hydration, collagen, proteoglycan, and hydroxypyridinium crosslink density). Tensile properties, biochemical composition, and anatomic location were compared. Significant radial and circumferential variations in tensile properties of anulus were detected, with the anterior being stiffer than the posterolateral regions, and the outer being stiffer than the inner regions. The regional differences in tensile properties may result predominantly from structural rather than compositional variations and may contribute to the clinical frequency of anulus failure in the posterolateral region.
Abstract: In medicine, objects that need to be removed later-such as stents-are commonly placed i... more Abstract: In medicine, objects that need to be removed later-such as stents-are commonly placed in patients, with the time of removal dependent on progress of the patient. In these cases biodegradable materials that last for a specific time may not be suitable. We propose a new class of nanostructured materials that can hold their form as long as wanted, Triggered, Nanostructured Biodegradables (TNBs), that can be disintegrated to micro-or nanoscaled components when externally triggered on command to do so.
Purpose. According to the conventional arch model of the pelvis, stability of the sacroiliac join... more Purpose. According to the conventional arch model of the pelvis, stability of the sacroiliac joints may requires a predominance of form and force closure mechanisms: the greater the vertical shear force at the sacroiliac joints, the greater the reliance on self-bracing by horizontal or obliquely oriented muscles (such as the internal oblique). But what happens to the arch model when a person stands on one leg? In such cases, the pelvis no longer has imposts, leaving both the arch, and the arch model theory, without support. Do lumbopelvic muscle activation patterns in one-legged stances under load suggest compatibility with a different model? This study compares lumbopelvic muscle activation patterns in two-legged and one-legged stances in response to four levels of graded trunk loading in order to further our understanding the stabilization of the sacroiliac joints.
The scapula is a sesamoid bone. Stephen Michael Levin. Potomac Back Center, 8608 Dixie Place, Mcl... more The scapula is a sesamoid bone. Stephen Michael Levin. Potomac Back Center, 8608 Dixie Place, Mclean, VA 22102, USA. Available online 26 January 2005. Article Outline. References. Gupta and van der Helm (2004) use finite ...
The structure-function relationship of anulus fibrosus of nondegenerate lumbar intervertebral dis... more The structure-function relationship of anulus fibrosus of nondegenerate lumbar intervertebral discs was investigated. The tensile properties and biochemical composition of single lamella specimens from human anulus fibrosus and their variations with anatomic region were determined. Regional differences in composition and ultrastructure suggest differences in tensile properties. Single lamella specimens were isolated from the anulus, equilibrated in 0.15 mol/L NaCl and tested in uniaxial tension using a slow strain-rate protocol. Adjacent specimens were used to determine biochemical composition (including hydration, collagen, proteoglycan, and hydroxypyridinium crosslink density). Tensile properties, biochemical composition, and anatomic location were compared. Significant radial and circumferential variations in tensile properties of anulus were detected, with the anterior being stiffer than the posterolateral regions, and the outer being stiffer than the inner regions. The regional differences in tensile properties may result predominantly from structural rather than compositional variations and may contribute to the clinical frequency of anulus failure in the posterolateral region.
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