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  • Life and Medical Sciences
  • Space Transportation and Safety
  • 2005-2009  (3)
  • 1980-1984  (1)
  • 1970-1974  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Aspects of the ultrastructure of the alimentary canal and respiratory ducts in Xenopus laevis larvae (1972)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 138 (1972), S. 387-405 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pharynx, intestine and respiratory duct of Xenopus laevis were examined by light and electron microscopy, at different stages of the metamorphic cycle, through climax.It is well known that preclimactic larvae are suspension feeders and that after climax specimens feed on solid food. It is shown that the histology of the pharynx and the alimentary canal changes in adaptation to the change in the mode of feeding.Suspension feeding utilises ciliary activity but after climax cilia have disappeared from the pharynx and alimentary canal, when new neuromuscular mechanisms are utilised in feeding.Other morpho-histological changes in various intestinal and respiratory tissues are likewise considered in terms of functional activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051380402
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    DNA-mediated transformation of mammalian cells in culture. Increased transforming efficiency following sonicationThis work was supported, in part, by USPHS Research grants RO1-CA04534 from the National Cancer Institute and RO1-GM14514 from the National Institute of General Medical Sciences. (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 75 (1970), S. 137-150 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A series of 100 experiments was completed to determine if DNA is capable of transforming the genotype of a murine lymphoma (P388) in cell culture. The test system was concerned with the transformation of cells from 8-azaguanine (AZG) sensitivity to resistance. By the use of this marker, it was determined that transformation by DNA did occur, and that the efficiency of transformation was greatly increased by sonication of the DNA. A statistical analysis of 100 experiments demonstrated that the increase in the number of resistant cells after treatment with sonicated resistant DNA (R-DNA) was statistically significant (χ2 〉 4.25, 0.05 〉 p 〉 0.02) in 66% of the experiments. DNA from sensitive parental cells and DNA from other sources produced no effect while DNase and UV treatment abrogated effective transformation by either sonicated or nonsonicated R-DNA. RNase was without effect.Sucrose gradient analysis of sonicated and nonsonicated R-DNA demonstrated that the peaks which correspond to the highest specific transforming activity are not altered by sonication and do not coincide with the OD260 peaks, in spite of the fact that sonication shifted the peak of maximum OD260 to a slower sedimenting region of the gradient. The major portion, however, of the transforming material did shift after sonication to the slower sedimenting region of the gradient and did coincide with the OD260 peak.The hereditary stability of the transformed cells was established by cloning a representative number of transformants, growing them in the absence of AZG for an extended period and then testing their ability to grow in graded concentrations of AZG. In addition, DNA extracted from transformants successfully transformed sensitive cells.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040750202
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  • 3
    Electronic Resource
    Electronic Resource
    The mechanism of cumulus cell-oocyte uncoupling: Evidence for the participation of both cumulus cells and oocytes (1982)
    New York, NY : Wiley-Blackwell
    Gamete Research 6 (1982), S. 145-154 
    Details
    ISSN: 0148-7280
    Keywords: oocyte maturation ; cumulus oophorus ; gonadotropins ; intercellular coupling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cumulus cells are metabolically coupled to oocytes via heterologous gap junctions. This coupling terminates near the time of ovulation, and the termination appears to be correlated with the mucification of the cumulus cells lying immediately adjacent to the oocytes. The first objective of this project was to determine whether follicle stimulating hormone (FSH) induction of cumulus cell-oocyte uncoupling could occur independently of FSH-stimulated cumulus mucification (expansion). Intercellular coupling was measured as a percentage of radiolabeled choline (or its metabolites) that was incorporated into the oocyte relative to the total amount of radiolabel incorporated into the entire cumulus cell-oocyte complex. It was found that the complete suppression of FSH-stimulated cumulus expansion with chondroitin sulfate B had no suppressive effect on FSH-stimulated cumulus cell-oocyte uncoupling. This finding showed that FSH-stimulated cumulus expansion was not required for cumulus cell-oocyte uncoupling. Since 17β-estradiol, testosterone, or progesterone could not induce maximal cumulus cell uncoupling, it was concluded that the uncoupling-promoting action of FSH was probably not mediated by steroid hormones.A partial uncoupling of cumulus cells and oocytes was found when spontaneous oocyte maturation had occurred in the absence of FSH. This partial uncoupling was prevented by incubation of cumulus cell-oocyte complexes in concentrations of dibutyryl cyclic adenosine monophosphate (dbcAMP) or 3-isobutyl-1-methyl xanthine (IBMX) (0.25 and 0.10 mM respectively) that suppressed spontaneous oocyte maturation without inducing cumulus expansion. These inhibitors also prevented the maximal induction of uncoupling that would have been provoked by biological grade preparations of either FSH or luteinizing hormone (LH). It was concluded that two factors were required to bring about maximal cumulus cell-oocyte uncoupling: one factor was dependent upon the action of gonadotropins on cumulus cell function, the other factor appeared to be a function of the oocytes, since maximal uncoupling could occur only after the germinal vesicles had broken down.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120060208
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  • 4
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    Evaluating the Effects of Dimensionality in Advanced Avionic Display Concepts for Synthetic Vision Systems (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Synthetic vision systems provide an in-cockpit view of terrain and other hazards via a computer-generated display representation. Two experiments examined several display concepts for synthetic vision and evaluated how such displays modulate pilot performance. Experiment 1 (24 general aviation pilots) compared three navigational display (ND) concepts: 2D coplanar, 3D, and split-screen. Experiment 2 (12 commercial airline pilots) evaluated baseline 'blue sky/brown ground' or synthetic vision-enabled primary flight displays (PFDs) and three ND concepts: 2D coplanar with and without synthetic vision and a dynamic multi-mode rotatable exocentric format. In general, the results pointed to an overall advantage for a split-screen format, whether it be stand-alone (Experiment 1) or available via rotatable viewpoints (Experiment 2). Furthermore, Experiment 2 revealed benefits associated with utilizing synthetic vision in both the PFD and ND representations and the value of combined ego- and exocentric presentations.
    Keywords: Space Transportation and Safety
    Type: LF99-5989
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Cooper-Harper Experience Report for Spacecraft Handling Qualities Applications (2009)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A synopsis of experience from the fixed-wing and rotary-wing aircraft communities in handling qualities development and the use of the Cooper-Harper pilot rating scale is presented as background for spacecraft handling qualities research, development, test, and evaluation (RDT&E). In addition, handling qualities experiences and lessons-learned from previous United States (US) spacecraft developments are reviewed. This report is intended to provide a central location for references, best practices, and lessons-learned to guide current and future spacecraft handling qualities RDT&E.
    Keywords: Space Transportation and Safety
    Type: NASA/TM-2009-215767 , L-19695 , LF99-8892
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Synthetic and Enhanced Vision System for Altair Lunar Lander (2009)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Past research has demonstrated the substantial potential of synthetic and enhanced vision (SV, EV) for aviation (e.g., Prinzel & Wickens, 2009). These augmented visual-based technologies have been shown to significantly enhance situation awareness, reduce workload, enhance aviation safety (e.g., reduced propensity for controlled flight -into-terrain accidents/incidents), and promote flight path control precision. The issues that drove the design and development of synthetic and enhanced vision have commonalities to other application domains; most notably, during entry, descent, and landing on the moon and other planetary surfaces. NASA has extended SV/EV technology for use in planetary exploration vehicles, such as the Altair Lunar Lander. This paper describes an Altair Lunar Lander SV/EV concept and associated research demonstrating the safety benefits of these technologies.
    Keywords: Space Transportation and Safety
    Type: LF99-8443 , 15th International Symposium on Aviation Psychology; Apr 27, 2009 - Apr 30, 2009; Dayton, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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