76 research outputs found
Trabecular and cortical bone structure of the talus and distal tibia in Pan and Homo.
No full textObjectives: Internal bone structure, both cortical and trabecular bone, remodels in response to loading and may provide important information regarding behavior. The foot is well suited to analysis of internal bone structure because it experiences the initial substrate reaction forces, due to its proximity to the substrate. Moreover, as humans and apes differ in loading of the foot, this region is relevant to questions concerning arboreal locomotion and bipedality in the hominoid fossil record.
Materials and methods: We apply a whole-bone/epiphysis approach to analyze trabecular and cortical bone in the distal tibia and talus of Pan troglodytes and Homo sapiens. We quantify bone volume fraction (BV/TV), degree of anisotropy (DA), trabecular thickness (Tb.Th), bone surface to volume ratio (BS/BV), and cortical thickness and investigate the distribution of BV/TV and cortical thickness throughout the bone/epiphysis.
Results: We find that Pan has a greater BV/TV, a lower BS/BV and thicker cortices than Homo in both the talus and distal tibia. The trabecular structure of the talus is more divergent than the tibia, having thicker, less uniformly aligned trabeculae in Pan compared to Homo. Differences in dorsiflexion at the talocrural joint and in degree of mobility at the talonavicular joint are reflected in the distribution of cortical and trabecular bone.
Discussion: Overall, quantified trabecular parameters represent overall differences in bone strength between the two species, however, DA may be directly related to joint loading. Cortical and trabecular bone distributions correlate with habitual joint positions adopted by each species, and thus have potential for interpreting joint position in fossil hominoids
Religijos tema XX a. anglų metafizinėje poezijoje (naujosios apokalipsės poezija 1939–1941 m.)
No full textThe paper analyzes the transformation of the themes, poetics and stylistics of metaphysical poetry in the works of H. Treece, J. F. Hendry, N. Moore, T. Scott et al. associated with the Apocalyptic Movement in British literature. The material for the analysis is taken from their second anthology, “The White Horseman”, published in 1941. The poetry of the New Apocalypse is considered in comparison with the works of British and continental metaphysical poets of the 17th, 19th and 20th centuries (R. Crashaw, F. de Quevedo, G. M. Hopkins, et al). The main focus is on the theme of religion. The paper explains the new configuration of traditional key themes (Religion, Death and Time, Love) in the works of the 20th century poets, and shows new details in their interpretation of the relations between God and man. The research concentrates on the development of certain motifs such as ‘the death of God’ (a motif known since Victorian times), and demonstrates several new accents brought to traditional issues within the theme of religion (e.g. the desolation of human being). The paper also considers the new developments in the field of traditional poetics and stylistics of metaphysical poetry. The author analyzes the use of gospel paraphrases, polysemantic words and expressions, examples or word- play, etc. in the religious poetry of the Apocalyptic Movement
Targeted Regeneration of Bone in the Osteoporotic Human Femur
No full textWe have recently developed image processing techniques for measuring the cortical thicknesses of skeletal structures in vivo, with resolution surpassing that of the underlying computed tomography system. The resulting thickness maps can be analysed across cohorts by statistical parametric mapping. Applying these methods to the proximal femurs of osteoporotic women, we discover targeted and apparently synergistic effects of pharmaceutical osteoporosis therapy and habitual mechanical load in enhancing bone thickness
Changes in Body Measurements of Heifers at First Parturition
No full textAuthor Institution: Department of Dairy Science, Ohio Agricultural Experiment Station, Wooste
Automatic Segmentation and Discrimination of Connected Joint Bones from CT by Multi-atlas Registration
No full textThe Booster/Delta nexus : Henry Miller and his friends in the literary world of Paris and London on the eve of the Second World War.
No full text3D ultrasound probe calibration without a position sensor
No full textWe present a technique for 3D ultrasound probe calibration which does not require measurements from the position sensor. The principle of operation is that the beam is aligned with a set of coplanar wires strung across a rigid frame. The probe and frame are mounted on a precision-manufactured mechanical instrument which allows adjustment and measurement of their relative pose. Semi-automatic image processing facilitates alignment of the beam and wires to within a tolerance of around 200 µm, despite the considerable beam thickness. The calibration process requires just a single view and relatively little user expertise. In a series of experiments with different ultrasound probes, we demonstrate the technique’s high accuracy and precision. The latter is partly due to the elimination of the position sensor, a significant source of measurement noise, from the end-user calibration process.
Optimization strategies for ultrasound volume registration
No full textThis paper considers registration of 3D ultrasound volumes acquired in multiple views for display in a single image volume. One way to acquire 3D data is to use a mechanically swept 3D probe. However, the usefulness of these probes is restricted by their limited field of view. This problem can be overcome by attaching a six-degree-of-freedom (DOF) position sensor to the probe, and displaying the information from multiple sweeps in their proper positions. However, an external six-DOF position sensor can be an inconvenience in a clinical setting. The objective of this paper is to propose a hybrid strategy that replaces the sensor with a combination of three-DOF image registration and an unobtrusive inertial sensor for measuring orientation. We examine a range of optimization algorithms and similarity measures for registration and compare them in in vitro and in vivo experiments. We register based on multiple reslice images rather than a whole voxel array. In this paper, we use a large number of reslices for improved reliability at the expense of computational speed. We have found that the Levenberg–Marquardt method is very fast but is not guaranteed to give the correct solution all the time. We conclude that normalized mutual information used in the Nelder–Mead simplex algorithm is potentially suitable for the registration task with an average execution time of around 5 min, in the majority of cases, with two restarts in a C++ implementation on a 3.0 GHz Intel Core 2 Duo CPU machine
An intelligent interface for freehand strain imaging
No full textWe present a new, intelligent interface for freehand strain imaging, which has been designed to support clinical trials investigating the potential of ultrasonic strain imaging for diagnostic purposes across a broad range of target pathologies. The aim with this interface is to make scanning easier, and to help clinicians learn the necessary scanning technique quickly, by providing real time feedback indicating the quality of the strain data as they are produced. The images are also easier to interpret, because data at unacceptably low signal-to-noise ratios do not reach the display. Overall, the interface also considerably reduces the difficulty in producing volumes of strain data from freehand 3D scans. Its main components are novel normalisation, persistence and display methods. These not only present data in a more meaningful format, but the level of noise in the displayed images is actually reduced compared to other methods that use the same strain estimates with the same level of persistence.
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