4,814 research outputs found
Towards quantitative 3D imaging of the osteocyte lacuno-canalicular network
No full textOsteocytes are the most abundant cells in bone and the only cells embedded in the bone mineral matrix. They form an extended, three-dimensional (3D) network, whose processes interconnecting the cell bodies reside in thin canals, the canaliculi. Together with the osteocyte lacunae, the canaliculi form the lacuno-canalicular network (LCN). As the negative imprint of the cellular network within bone tissue, the LCN morphology is considered to play a central role for bone mechanosensation and mechanotransduction. However, the LCN has neither been visualized nor quantified in an adequate way up to now. On this account, this article summarizes the current state of knowledge of the LCN morphology and then reviews different imaging methods regarding the quantitative 3D assessment of bone tissue in general and of the LCN in particular. These imaging methods will provide new insights in the field of bone mechanosensation and mechanotransduction and thus, into processes of strain sensation and transduction, which are tightly associated with osteocyte viability and bone quality
Serial FIB/SEM imaging for quantitative 3D assessment of the osteocyte lacuno-canalicular network
No full textUp to now, a quantitative three-dimensional (3D) assessment of the lacuno-canalicular network (LCN) within bone has not been achieved in a comprehensive way and the LCN has mostly been investigated using two-dimensional imaging methods only. First attempts for the 3D assessment of the osteocytes and their cell processes have been reported using different imaging techniques. Nevertheless, various experimental limitations allowed for assessment of isolated or incompletely interconnected osteocytes only. On the other hand, serial focused ion beam/scanning electron microscopy (FIB/SEM) currently seems to be a promising imaging method for quantitative 3D assessment of the LCN. However, combined 3D visualization and quantification of the LCN using serial FIB/SEM imaging has not been reported so far. The aim of this study was to provide a proof of concept that serial FIB/SEM meets all requirements for quantitative 3D imaging of the LCN. To this end, we developed a new bone sample preparation protocol for serial FIB/SEM imaging providing a resolution on the order of 30 nm. This technique was successfully applied to the mid-diaphysis of a mouse femur. Moreover, we devised and applied novel measures for subsequent quantitative 3D morphometry of the LCN. Briefly, serial FIB/SEM was shown to be an appropriate technique to quantify the morphology of the LCN truly in 3D. This will allow investigating bone matrix changes on an ultrastructural level, which result from aging, disease, and treatmen
Roger Abrahams, author
No full textRoger Abrahams, director of the African and Afro-American Research Institute at the University of Texas-Austin and author of Positively Black, argues the case for ethnic diversity in this interview. He also discusses that the idea of "new ethnicity" is not restricted to black or brown America and he sees a widespread return to old mores inherent in the traditional ethnic value system. Interviewed by WTMJ-TV host Jim Peck.GrayscaleSoun
Unlucky for Some : 13 poems by Roger McGough
No full textInspired by and featuring the poetry of Roger McGough (by permission of the author), Unlucky for Some is a spare, minimalistic work about homelessness, mental illness and class division performed entirely in slow motion.\ud
\ud
This multimedia work also utilised prerecorded and live feed video and music, and experimented with synchronous and asynchonous live and mediatised performance
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
A Conversation with Roger Welsch
No full textIn this session, moderated by Barre Toelken and William A. "Bert" Wilson, audience members have the opportunity to discuss Roger Welsch's plenary lecture, and his other works and ideas, with the author
Spoken language reference materials
No full textContent of the CD distributed with the Handbook of Standards and Resources for Spoken Language Systems. Edited by Dafydd Gibbon, Roger Moore, Richard Winski. Published by Mouton de Gruyter, 1997
Ptychographic X-ray computed tomography at the nanoscale
No full textX-ray tomography is an invaluable tool in biomedical imaging. It can deliver the three-dimensional internal structure of entire organisms as well as that of single cells, and even gives access to quantitative information, crucially important both for medical applications and for basic research1, 2, 3, 4. Most frequently such information is based on X-ray attenuation. Phase contrast is sometimes used for improved visibility but remains significantly harder to quantify5, 6. Here we describe an X-ray computed tomography technique that generates quantitative high-contrast three-dimensional electron density maps from phase contrast information without reverting to assumptions of a weak phase object or negligible absorption. This method uses a ptychographic coherent imaging approach to record tomographic data sets, exploiting both the high penetration power of hard X-rays and the high sensitivity of lensless imaging7, 8, 9. As an example, we present images of a bone sample in which structures on the 100?nm length scale such as the osteocyte lacunae and the interconnective canalicular network are clearly resolved. The recovered electron density map provides a contrast high enough to estimate nanoscale bone density variations of less than one per cent. We expect this high-resolution tomography technique to provide invaluable information for both the life and materials science
Conservative philosopher Roger Scruton delivers last of 'Democracy and Moral Conviction' lectures
No full textIncludes descriptive metadata provided by producer in MP3 file: "Listen to Roger Scruton, author of The Meaning of Conservatism and Arguments for Conservatism, lecture on 'Freedom of Religion' at Vanderbilt Law School on April 16, 2007. The lecture was the fourth and last of the 'Democracy and Moral Conviction' lecture series.
Hart (A. Tin dal). William Lloyd, bishop, politician, author and prophet, 1627-1717.
No full textAubert Roger. Hart (A. Tin dal). William Lloyd, bishop, politician, author and prophet, 1627-1717.. In: Revue belge de philologie et d'histoire, tome 33, fasc. 4, 1955. pp. 967-969
- …
