2,330 research outputs found
Forces and Structures of the Herpes Simplex Virus (HSV) Entry Mechanism.
This paper discusses physical and structural aspects of the mechanisms herpes simplex virus (HSV) uses for membrane fusion. Calculations show that herpes simplex virus glycoprotein D has such avidity for its receptors that it can hold the virion against the plasma membrane of a neuron strongly enough for glycoprotein B (gB) to disrupt both leaflets of the bilayer. The strong electric field generated by the cell potential across perforations at this disruption would break the hydrogen bonds securing the gB fusion loops, leading to fusion of the plasma and viral membranes. This mechanism agrees with the high stability of the tall trimeric spike structure of gB and is consistent with the probable existence of a more compact initial conformation that would allow it to closely approach the plasma membrane. The release of the fusion domains by disruption of hydrogen bonds is shared with the endocytotic entry pathway where, for some cell types not punctured by gB, the virus is able to induce inward forces that cause endocytosis and the fusion loops are released by acidification. The puncture-fusion mechanism requires low critical strain or high tissue strain, matching primary tropism of neural processes at the vermillion border. In support of this mechanism, this paper proposes a functional superstructure of the antigens essential to entry and reviews its consistency with experimental evidence
The Neo-Platonic Christianity of C. S. Lewis
I shall attempt to show how Lewis’s fusion of Platonism with Christianity gives rise to his belief, metaphysically speaking, that the physical universe is not all there is but, rather, “transposes” (as he terms it) a greater non-physical or spiritual reality and is, as such, part of a divinely-ordained, orderly, and purposeful scheme of things. I shall also argue that for Lewis, epistemologically speaking, knowledge of this grand design and the place of humans therein is conveyed not through the human senses, at least as these are conventionally conceived, but, rather, through our higher reason, which is capable of objective insight into the true nature of reality. I shall conclude by contending that Lewis believes, from an ethical, social, and political point of view, that well-doing and well-being at both the individual and collective levels are attained through a combination of wisdom as to the true nature of things, the courage to act in accordance with this knowledge, the moderation of self-interest in the form of the surrender of one’s individual will to God’s, and, last but not least, justice in the form of a hierarchy of functions both within the soul and without
Paradise Retained: C. S. Lewis on the Nature of Knowledge, Reality, and Morality in Perelandra
The world-view which informs Perelandra (1943) in particular and the so-called “space trilogy” more generally, of which it is the second volume, is deeply infused with that blend of Christianity and Platonism that is the hallmark of the thought of C. S. Lewis and which I explore at some length in the companion essay to this piece in this volume, “The Neoplatonic Christianity of C. S. Lewis.” Perelandra is, I would argue, a literary rendition of some of the most important philosophical arguments in defense of Christianity mounted by Lewis in Mere Christianity and elsewhere
Earth-Moon trajectories, 1965-70
Analytical model for generation of earth-moon trajectory analysis dat
Next generation software environments : principles, problems, and research directions
The past decade has seen a burgeoning of research and development in software environments. Conferences have been devoted to the topic of practical environments, journal papers produced, and commercial systems sold. Given all the activity, one might expect a great deal of consensus on issues, approaches, and techniques. This is not the case, however. Indeed, the term "environment" is still used in a variety of conflicting ways. Nevertheless substantial progress has been made and we are at least nearing consensus on many critical issues.The purpose of this paper is to characterize environments, describe several important principles that have emerged in the last decade or so, note current open problems, and describe some approaches to these problems, with particular emphasis on the activities of one large-scale research program, the Arcadia project. Consideration is also given to two related topics: empirical evaluation and technology transition. That is, how can environments and their constituents be evaluated, and how can new developments be moved effectively into the production sector
Alternative approach for defining the particle population requirements for static image analysis based particle characterization methods
Ceratoscopelus maderensis : pecular sound-scattering layer identified with this myctophid fish
Reprint. Science, vol. 160, no. 3831, 1968, pp. 991-993. Originally issued as Reference No. 68-58, series later renamed WHOI-.A sound- scattering layer, composed of discrete
hyperbolic echo-sequences and apparently restricted to the
Slope Water region of the western North Atlantic, has been
identified from the Deep Submergence Research Vehicle ALVIN
with schools of the myctophid fish Ceratoscopelus maderensis.
By diving into the layer and using ALVIN's echo-ranging sonar,
we approached and visually identified the sound scatterers. The
number of echo sequences observed with the surface echo-sounder
(1 /23. 76 x 105 cubic meters of water) checked roughly with the
number of sonar targets observed from the submarine (1/7. 45 x
105 cubic meters) . The fish schools appeared to be 5 to 10 meters
thick, 10 to 100 meters in diameter, and on centers 100 to 200
meters apart. Density within schools was estimated at 10 to 15
fish per cubic meter.Supported in part by contracts Nonr-3484(00)
and Nonr-4029(00) and by NSF grant GB-4431
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