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Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90 degrees, they temporarily grow down soon after reorientation ("initial reversal") and also prior to cytokinesis ("mitotic reversal"). A positively gravitropic mutant designated wrong- way response (wwr-1)(More)
STUDY DESIGN A retrospective analysis. OBJECTIVE To quantify the risks of surgery and explore the associations of early perioperative complications with patient demographics and surgical variables. SUMMARY OF BACKGROUND DATA Long fusions extending from the thoracic spine to the pelvis in adults are increasingly common. Currently, there are few studies(More)
STUDY DESIGN biomechanical testing of the strength and stability of lumbosacral fixation constructs. OBJECTIVES The purpose of this study was to quantify and compare the biomechanical properties of five different lumbosacral fixation constructs and determine the benefit of adding supplementary fixation to S1 screws. SUMMARY OF BACKGROUND DATA Extension(More)
Moss protonemata are a valuable system for studying gravitropism because both sensing and upward curvature (oriented tip growth) take place in the same cell. We review existing evidence, especially for Ceratodon purpureus, that addresses whether the mass that functions in sensing is that of amyloplasts that sediment. Recent experiments show that(More)
STUDY DESIGN Retrospective cohort. OBJECTIVE The objective of this study was to define the intraoperative radiation exposure during freehand surgical technique with fluoroscopic assistance for placement and confirmation of posterior instrumentation in patients with adolescent idiopathic scoliosis and compare data with published values using intraoperative(More)
STUDY DESIGN Retrospective review of sacral insufficiency fractures. OBJECTIVE Determine incidence of sacral insufficiency fractures after posterior lumbosacral fusion. Review the pertinent literature. Describe the ability of lumbopelvic fixation to restore the alignment of these fractures. SUMMARY OF BACKGROUND DATA Fractures of the sacrum are rare(More)
Wild-type (WT) protonemata of the moss Ceratodon purpureus grow upwards in darkness (negative gravitropism), whereas protonemata of the mutant, wrong-way response (wwr-1) grow down. Since Ceratodon protoplasts regenerate to form new protonemata, we analyzed whether the direction of filament emergence was influenced by gravity (gravimorphism) and determined(More)
Determinations of plant or algal cell density (cell mass divided by volume) have rarely accounted for the extracellular matrix or shrinkage during isolation. Three techniques were used to indirectly estimate the density of intact apical cells from protonemata of the moss Ceratodon purpureus. First, the volume fraction of each cell component was determined(More)
An academic orthopedic residency program can have a significant impact on the burden of musculoskeletal disease in low- and middle-income countries. Such an exposure may also enhance the education of a resident. A 17-question electronic survey was developed to quantify the interest of orthopedic residents in pursuing an elective international rotation. The(More)
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