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Hyperbole has become a common and accepted practice in science nowadays. We sell our results, we hide our ignorance and we use stock terms that gain spurious weight through repeated use. I illustrate from the field of developmental genetics.
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For most proteins the amino acid sequence determines the tertiary structure. The relative importance of the individual amino acids in specifying the fold, however, remains unclear. To highlight this, Creamer and Rose put forth the 'Paracelsus challenge': Design a protein with 50% sequence identity to a protein with a different fold. We have met this challenge by designing a sequence which retains 50% identity to a predominantly beta-sheet protein, but which now adopts a four helix bundle conformation and possesses the attributes of a native protein. Our results emphasize that a subset of the amino acid sequence is sufficient to specify a fold, and have implications both for structure prediction and design.
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Observers perceive incoherent motion and no hint of depth when viewing stochastic motion, in which stimulus elements move in all possible directions. As earlier work has shown, depth can be specified by introducing a brief interocular delay between the presentation of corresponding animation frames of this 'noise' to the left and right eyes. A study is reported in which observers were adapted to a stereoscopic display consisting of coherent planes of motion at different depths. This stereoscopic adaptation caused incoherent depthless motion to take on the qualities of structure and depth, and it could nullify the depth induced by interocular delay. The findings are interpreted within the context of a neural model consisting of units selectively responsive to different directions of motion at different planes of depth.
Group-as-a-whole theory is a relational paradigm of some complexity. Despite the growing popularity of this perspective, there is abiding confusion about the essence of group-as-a-whole practice and whether the approach attends sufficiently to members and part processes. The threefold aims of this article are to (a) show how group-centered thinking differs essentially from traditional psychodynamic theory that relies heavily on familial dynamics, interpretation, and transference analysis; (b) present the mind-set and working principles for a generic treatment that specifically utilizes collective forces generated in the context of the group matrix; and (c) compare and contrast the thrust of recent dyadic relational therapies with group therapy generally and the group-as-a-whole approach more particularly. The relationship between the whole (group) and its parts (members and what they bring) is detailed and demonstrated as it appears in the context of fused, affiliated, fragmented, and differentiated groups.
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Hospital turnarounds are an increasing phenomenon in an era of unrelenting financial pressure on the health care delivery system. However, the literature about hospital turnarounds contains more theories and case reports than research studies, and repeat turnarounds suggest that there is inadequate evidence about what really works. The essential role of the turnaround agent in strategy formulation and especially strategy implementation is the subject of this article. It casts a wide net over the literature of strategy, change, leadership, and management. The article traces the nature and evolution of hospital turnarounds plus the agents that effect them; summarizes the turnaround agent's 10 most potent approaches to strategy analysis and synthesis; and outlines 3 research questions about first, the recurring need for hospital turnarounds altogether; second, longitudinal evidence to support different turnaround approaches; and third, the mechanisms by which the turnaround agent both changes and is changed by the distressed hospital.
Adipose tissue contains a population of pluripotent stem cells capable of differentiating along multiple mesenchymal cell lineages. In this study the authors isolated these fat-derived stem cells successfully from Lewis rats and induced differentiation along adipogenic and osteogenic lineages in vitro and in vivo. Induction was stimulated by exposing stem cells to lineage-specific induction factors. Adipocyte-inducing media contained dexamethasone, insulin, and isobutyl-methylxanthine. Osteoblast inducing media contained dexamethasone, beta-glycerophosphate, and ascorbic acid. Undifferentiated stem cells were maintained in minimal essential media alpha and fetal bovine serum. At 10 days, cells cultured in adipogenic media differentiated into adipocytes in vitro, as evidenced by positive Oil red O staining of lipid vacuoles. At 21 days, cells cultured in osteogenic media differentiated into osteoblasts in vitro as demonstrated by Alizarin red staining of a calcified extracellular matrix and immunohistochemical staining for osteocalcin. Differentiated cells were seeded at a density of 5 x 106 cells onto 15 x 15-mm polyglycolic acid grafts and implanted subcutaneously into three groups of Lewis rats: Group I contained undifferentiated stem cell grafts, group II contained adipocyte grafts, and group III contained osteoblast grafts. At weeks 4 and 8, in vivo fat formation was demonstrated in group II rats, as confirmed by Oil red O staining. At 8 weeks, group III rats demonstrated in vivo bone formation, as confirmed by the presence of osteocalcin on immunohistochemistry and the characteristic morphology of bone on hematoxylin-eosin staining. Group I rats demonstrated no in vivo bone or fat formation at either time interval. These results demonstrate the ability to isolate pluripotent stem cells from adipose tissue, to induce their differentiation into osteoblasts and adipocytes in vitro, and to form bone and fat subsequently in vivo. This is the first published report of in vivo bone formation from fat-derived stem cells. These cells may eventually serve as a readily available source of autologous stem cells for the engineering of bone and fat.
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