[ { "id": "authors:4g81b-med79", "collection": "authors", "collection_id": "4g81b-med79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160322-120549369", "type": "article", "title": "The \u03b1_4 Subunit of Integrin Is Important for Neural Crest Cell Migration", "author": [ { "family_name": "Kil", "given_name": "Sung H.", "clpid": "Kil-Sung-H" }, { "family_name": "Krull", "given_name": "Catherine E.", "clpid": "Krull-C-E" }, { "family_name": "Cann", "given_name": "Gordon", "clpid": "Cann-G-L" }, { "family_name": "Clegg", "given_name": "Dennis", "clpid": "Clegg-D" }, { "family_name": "Bronner-Fraser", "given_name": "Marianne", "orcid": "0000-0003-4274-1862", "clpid": "Bronner-M-E" } ], "abstract": "We identify the \u03b1_4 subunit of integrin as a predominant integrin expressed by neural crest cells in both avian and murine embryos. Using degenerate primers, we obtained a PCR fragment of the chick integrin \u03b1_4 subunit that was subsequently used to clone the full-length subunit with a predicted amino acid sequence 60% identical to human and mouse \u03b1_4 subunits.In situhybridization demonstrates that chick integrin \u03b1_4 mRNA is expressed at high levels by migrating neural crest cells and neural crest-derived ganglia at both cranial and trunk levels. An antibody against the murine \u03b1_4 subunit revealed similar distribution patterns in mouse to chick. In addition to neural crest cells, the integrin \u03b1_4 subunit was later observed on the muscle masses of the limb, the apical ectodermal ridge, and the developing liver. To examine the functional role of the integrin \u03b1_4 subunit in neural crest cell migration, we used an explant preparation that allows visualization of neural crest cells in their normal environment with or without perturbing reagents. In the presence of a blocking antibody against the mouse integrin \u03b1_4 subunit, there was a profound abrogation of neural crest cell migration at trunk and hindbrain levels. Both the numbers of migrating neural crest cells and the total distance traversed were markedly reduced. Similarly, avian embryos injected with synthetic peptides that contain the integrin \u03b1_4 binding site in fibronectin displayed abnormal neural crest cell migration. Our results suggest that the integrin \u03b1_4 subunit is important for normal neural crest cell migration and may be one of the primary \u03b1 subunits used for neural crest cell migrationin vivo.Furthermore, the integrin \u03b1_4 subunit represents a useful neural crest marker in the mouse.", "doi": "10.1006/dbio.1998.8985", "issn": "0012-1606", "publisher": "Elsevier", "publication": "Developmental Biology", "publication_date": "1998-10-01", "series_number": "1", "volume": "202", "issue": "1", "pages": "29-42" }, { "id": "authors:stpwx-3kc10", "collection": "authors", "collection_id": "stpwx-3kc10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151105-152212860", "type": "monograph", "title": "Energy Transfer Processes in a Partially Ionized Gas", "author": [ { "family_name": "Cann", "given_name": "Gordon L.", "clpid": "Cann-G-L" } ], "abstract": "The following paper is divided into three more or less separate sections. The first section (Chapters II- VI) deals with an analysis of the transport properties of a partially ionized gas subject to the constraint\nthat the average random energy of all constituent particles\nis exactly equal (equipartition of energy). This constraint is necessary so that the formal Chapman-Enskog solution of Boltzman's equation can be used to evaluate the various transport coefficients. Subject to this constraint, a set of tractable equations describing the mass and energy\ndiffusion in a partially ionized gas is obtained that includes all terms correct to the order of the square root of the ratio of the electron to\natom mass compared to one. The transport coefficients are evaluated for helium and argon over the complete range of partial ionization assuming that the species particle densities are quite close to their equilibrium values.\n\nThe analysis indicates that the electron and ion diffusion\nvelocities are more closely coupled than the equations of Chapman and Cowling show. The added coupling implicitly applies the constraint of zero mass velocity to the gas locally. Because of this constraint a current in the direction of (E x B) x B occurs in addition to the direct\nand Hall currents.\n\nIt is shown that the only part of the thermal conductivity that can be influenced by a magnetic field is that part of the energy carried by the diffusion of the charged particles. For this reason, magnetic fields, in general, cannot be nearly as effective in reducing heat transfer\nrates as was previously thought, e. g., a magnetic field will have no influence on the thermal conductivity in a fully ionized gas, except through its influence on the current density and the thermal diffusion.\n\nChapters VII- IX comprise the second section of this paper and deal with the development of a similarity solution for axially symmetric electric discharges. A number of parameters are obtained and discussed. The solution is evaluated for a discharge in argon gas at one atmosphere pressure in which the temperature on the axis of\nthe discharge varies from 6,000\u00b0K to 19,000\u00b0K. The current-voltage characteristic obtained from this solution is compared with an experimentally determined curve of H. Maecker.\n\nThe third section of this paper (Chapters X - XIII) is concerned with the mechanisms of energy transfer in arc jet devices. Use is made of the previous sections of the paper to determine the relative magnitude of the amount of energy that is transferred to the gas in the various parts of the electric discharge. The various possible electrode\nconfigurations are discussed in detail and compared. The design and performance of an annular electrode arc heater with a rotating arc is next described and discussed. Because of a number of undesirable performance characteristics of this type of electrode configuration, a\nmodified heater was constructed with the cathode emission occurring along the axis of the applied magnetic field. Details of the unexpectedly good performance of this configuration are given. It is shown that the arc potential drop depends primarily on the strength of the applied\nmagnetic field and the gas enthalpy downstream of the arc. The dependence of the arc potential drop on the arc current and the ambient pressure is shown to be weak over the ranges tested, e. g., 50 to 300 amperes for the current and l to 4 atmospheres for the pressure. Some heat transfer measurements taken with this equipment are\npresented.\n\nAppendix I is concerned with the evaluation of the transport\ncoefficients in a partially ionized gas. Formulae are developed for determining the viscosity, thermal conductivity, and electric conductivity\nof the plasma. These coefficients are computed for argon\nand helium at one atmosphere pressure and over the temperature range of partial ionization.", "publisher": "California Institute of Technology", "publication_date": "1961-06-15" }, { "id": "authors:m1zjb-r2s64", "collection": "authors", "collection_id": "m1zjb-r2s64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120905-074408038", "type": "article", "title": "Electrical Conductivity of a Partially Ionized Gas", "author": [ { "family_name": "Cann", "given_name": "Gordon L.", "clpid": "Cann-G-L" } ], "abstract": "While investigating the energy transfer processes\noccurring between an electric arc and the surrounding\ngas, it was found desirable to study in detail the\ntransport properties of species diffusion and thermal flux\nin a partially ionized monatomic gas in the presence of a\nmagnetic field.", "doi": "10.1063/1.1706143", "issn": "1070-6631", "publisher": "American Institute of Physics", "publication": "Physics of Fluids", "publication_date": "1960-11", "series_number": "6", "volume": "3", "issue": "6", "pages": "1031-1032" } ]