4,370 research outputs found
Digital multiplexed mRNA analysis of functionally important genes in single human oocytes and correlation of changes in transcript levels with oocyte protein expression
Objective
To investigate functionally important transcripts in single human oocytes with the use of NanoString technology and determine whether observed differences are biologically meaningful.
Design
Analysis of human oocytes with the use of NanoString and immunoblotting.
Setting
University-affiliated reproductive medicine unit.
Patients
Women undergoing in vitro fertilization.
Intervention
Human oocytes were analyzed with the use of NanoString or immunoblotting.
Main Outcome Measures
The abundance of transcripts for ten functionally important genes—AURKA, AURKC, BUB1, BUB1B (encoding BubR1), CDK1, CHEK1, FYN, MOS, MAP2K1, and WEE2—and six functionally dispensable genes were analyzed with the use of NanoString. BubR1 protein levels in oocytes from younger and older women were compared with the use of immunoblotting.
Result(s)
All ten functional genes but none of the six dispensable genes were detectable with the use of NanoString in single oocytes. There was 3- to 5-fold variation in BUB1, BUB1B, and CDK1 transcript abundance among individual oocytes from a single patient. Transcripts for these three genes—all players within the spindle assembly checkpoint surveillance mechanism for preventing aneuploidy—were reduced in the same oocyte from an older patient. Mean BUB1B transcripts were reduced by 1.5-fold with aging and associated with marked reductions in BubR1 protein levels.
Conclusion(s)
The abundance of functionally important transcripts exhibit marked oocyte-to-oocyte heterogeneity to a degree that is sufficient to affect protein expression. Observed variations in transcript abundance are therefore likely to be biologically meaningful, especially if multiple genes within the same pathway are simultaneously affected
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Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction
The deformation of materials at cryogenic temperature is of interest for space, arctic, and fundamental science applications. In this work, a custom-built cooling system attached to a commercial picoindenter was used for in situ cryogenic microcompression testing of equal-channel angular-pressed copper with real-time electron backscatter diffraction. Stress-driven grain growth at cryogenic temperatures was observed during a series of elastic and plastic deformations. These results provide direct evidence for the previously predicted phenomenon, whereas previous ex situ examinations demonstrated coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization
Assessing the quality of a student-generated question repository
We present results from a study that categorizes and assesses the quality of
questions and explanations authored by students, in question repositories
produced as part of the summative assessment in introductory physics courses
over the past two years. Mapping question quality onto the levels in the
cognitive domain of Bloom's taxonomy, we find that students produce questions
of high quality. More than three-quarters of questions fall into categories
beyond simple recall, in contrast to similar studies of student-authored
content in different subject domains. Similarly, the quality of
student-authored explanations for questions was also high, with approximately
60% of all explanations classified as being of high or outstanding quality.
Overall, 75% of questions met combined quality criteria, which we hypothesize
is due in part to the in-class scaffolding activities that we provided for
students ahead of requiring them to author questions.Comment: 24 pages, 5 figure
Einstein's Real "Biggest Blunder"
Albert Einstein's real "biggest blunder" was not the 1917 introduction into
his gravitational field equations of a cosmological constant term \Lambda,
rather was his failure in 1916 to distinguish between the entirely different
concepts of active gravitational mass and passive gravitational mass. Had he
made the distinction, and followed David Hilbert's lead in deriving field
equations from a variational principle, he might have discovered a true (not a
cut and paste) Einstein-Rosen bridge and a cosmological model that would have
allowed him to predict, long before such phenomena were imagined by others,
inflation, a big bounce (not a big bang), an accelerating expansion of the
universe, dark matter, and the existence of cosmic voids, walls, filaments, and
nodes.Comment: 4 pages, LaTeX, 11 references, Honorable Mention in 2012 Gravity
Research Foundation Essay Award
Recent Langley helicopter acoustics contributions
The helicopter acoustics program at NASA Langley has included technology for elements of noise control ranging from sources of noise to receivers of noise. The scope of Langley contributions for about the last decade is discussed. Specifically, the resolution of two certification noise quantification issues by subjective acoustics research, the development status of the helicopter system noise prediction program ROTONET are reviewed and the highlights from research on blade rotational, broadband, and blade vortex interaction noise sources are presented. Finally, research contributions on helicopter cabin (or interior) noise control are presented. A bibliography of publications from the Langley helicopter acoustics program for the past 10 years is included
Follow-up after treatment for head and neck cancer: United Kingdom National Multidisciplinary Guidelines
This is the official guideline endorsed by the specialty associations involved in the care of head and neck cancer patients in the UK. In the absence of high-level evidence base for follow-up practices, the duration and frequency are often at the discretion of local centres. By reviewing the existing literature and collating experience from varying practices across the UK, this paper provides recommendations on the work up and management of lateral skull base cancer based on the existing evidence base for this rare condition
The biochemical, physiological, and metabolic evaluation of human subjects wearing pressure suits and on a diet of precooked freeze dehydrated foods
Biochemical, physiological and metabolic evaluation of human subjects wearing pressure suits and on diet of precooked frozen dehydrated food
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