We describe monozygotic twins with partially discordant phenotypes who were found to have a duplication of chromosome region 4q28.3-qter. The duplicated region of chromosome 4 resulted from an unbalanced segregation of a balanced maternal (4;22)(q28.3;p13) translocation. Duplication of the long arm of chromosome 4 has been described in >60 patients; however, it usually results from the unbalanced segregation of a parental balanced translocation and has an associated monosomy. Twenty cases of dup 4q without an associated monosomy have been reported, and this is the only case of dup 4q28. 3-qter. All cases of dup 4q are reviewed, and phenotypic aspects are analyzed. Issues of monozygotic twinning and other birth defects also are addressed.
Casting structural elements with ultra-high performance concrete (UHPC) tends to create preferential fiber alignment, which affects the strength and must be accounted for in design. To date, most work on fiber-orientation effects has been in tension rather than compression. This work characterizes the fiber orientation occurring in a typical UHPC beam and how that orientation affects compressive behavior at high strain rates. Specimens (36 total) were cored from the beam, and their fiber orientations were non-destructively evaluated using x-ray computed tomography. Fibers showed flow-induced alignment along the length of the beam. The perpendicular orientation number was used to describe orientation, as fibers perpendicular to the load were most effective in crack bridging. Quasi-static compressive strength appeared to increase with perpendicular orientation number, but the correlation is uncertain due to data limitations. Dynamic tests at strain rates of 130 to 200 s-1 were performed with a split-Hopkinson pressure bar. Dynamic compressive strength was independent of orientation number in these tests, although results suggested that the distribution and orientation of fibers influenced crack formation. The strain at peak stress, a measure of ductility, increased up to 25 percent over the range of perpendicular orientation numbers tested. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.
Birnbaum established and embarked upon an ambitious strategic plan for the Institute that continues to shape and support impactful research progress in both the intramural and extramural environmental health research communities. Throughout her 10-plus years as Director, Dr. Birnbaum has mobilized cross-disciplinary and collaborative efforts to support her vision of "One NIEHS." As she steps away from her official roles (but not from science), we, as members of her senior leadership team, have reflected upon and wish to pay tribute to her exemplary leadership and many accomplishments at and on behalf of the NIEHS. Accordingly, we highlight key areas in which Dr. Birnbaum stands out as a motivator, innovator, champion, and role model for us all.
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