Targeted disruption of the surfactant protein B gene disrupts surfactant homeostasis, causing respiratory failure in newborn mice.

Surfactant protein B (SP-B) is an 8.7-kDa, hydrophobic protein that enhances the spreading and stability of surfactant phospholipids in the alveolus. To further assess the role of SP-B in lung function, the SP-B gene was disrupted by homologous recombination in murine mouse embryonic stem cells. Mice with a single mutated SP-B allele (+/-) were unaffected, whereas homozygous SP-B -/- offspring died of respiratory failure immediately after birth. Lungs of SP-B -/- mice developed normally but remained atelectatic in spite of postnatal respiratory efforts. SP-B protein and mRNA were undetectable and tubular myelin figures were lacking in SP-B -/- mice. Type II cells of SP-B -/- mice contained no fully formed lamellar bodies. While the abundance of SP-A and SP-C mRNAs was not altered, an aberrant form of pro-SP-C, 8.5 kDa, was detected, and fully processed SP-C peptide was markedly decreased in lung homogenates of SP-B -/- mice. Ablation of the SP-B gene disrupts the routing, storage, and function of surfactant phospholipids and proteins, causing respiratory failure at birth.

Expression cloning of dSR-CI, a class C macrophage-specific scavenger receptor from Drosophila melanogaster.

Mammalian class A macrophage-specific scavenger receptors (SR-A) exhibit unusually broad binding specificity for a wide variety of polyanionic ligands. The properties of these receptors suggest that they may be involved in atherosclerosis and host defense. We have previously observed a similar receptor activity in Drosophila melanogaster embryonic macrophages and in the Drosophila macrophage-like Schneider L2 cell line. Expression cloning was used to isolate from L2 cells a cDNA that encodes a third class (class C) of scavenger receptor, Drosophila SR-CI (dSR-CI). dSR-CI expression was restricted to macrophages/hemocytes during embryonic development. When expressed in mammalian cells, dSR-CI exhibited high affinity and saturable binding of 125I-labeled acetylated low density lipoprotein and mediated its chloroquine-dependent, presumably lysosomal, degradation. Although the broad polyanionic ligand-binding specificity of dSR-CI was similar to that of SR-A, their predicted protein sequences are not similar. dSR-CI is a 609-residue type I integral membrane protein containing several well-known sequence motifs, including two complement control protein (CCP) domains and somatomedin B, MAM, and mucin-like domains. Macrophage scavenger receptors apparently mediate important, well-conserved functions and may be pattern-recognition receptors that arose early in the evolution of host-defense mechanisms. Genetic and physiologic analysis of dSR-CI function in Drosophila should provide further insights into the roles played by scavenger receptors in host defense and development.

On the nature of the galactic early-B hypergiants

Aims. Despite their importance to a number of astrophysical fields, the lifecycles of very massive stars are still poorly defined. In order to address this shortcoming, we present a detailed quantitative study of the physical properties of four early-B hypergiants (BHGs) of spectral type B1-4 Ia+; Cyg OB2 #12, ζ1 Sco, HD 190603 and BP Cru. These are combined with an analysis of their long-term spectroscopic and photometric behaviour in order to determine their evolutionary status. Methods. Quantitative analysis of UV–radio photometric and spectroscopic datasets was undertaken with a non-LTE model atmosphere code in order to derive physical parameters for comparison with apparently closely related objects, such as B supergiants (BSGs) and luminous blue variables (LBVs), and theoretical evolutionary predictions. Results. The long-term photospheric and spectroscopic datasets compiled for the early-B HGs revealed that they are remarkably stable over long periods ( ≥ 40 yrs), with the possible exception of ζ1 Sco prior to the 20th century; in contrast to the typical excursions that characterise LBVs. Quantitative analysis of ζ1 Sco, HD 190603 and BP Cru yielded physical properties intermediate between BSGs and LBVs; we therefore suggest that BHGs are the immediate descendants and progenitors (respectively) of such stars, for initial masses in the range ~30−60 M⊙. Comparison of the properties of ζ1 Sco with the stellar population of its host cluster/association NGC 6231/Sco OB1 provides further support for such an evolutionary scenario. In contrast, while the wind properties of Cyg OB2 #12 are consistent with this hypothesis, the combination of extreme luminosity and spectroscopic mass (~110 M⊙) and comparatively low temperature means it cannot be accommodated in such a scheme. Likewise, despite its co-location with several LBVs above the Humphreys-Davidson (HD) limit, the lack of long term variability and its unevolved chemistry apparently excludes such an identification. Since such massive stars are not expected to evolve to such cool temperatures, instead traversing an O4-6Ia → O4-6Ia+ → WN7-9ha pathway, the properties of Cyg OB2 #12 are therefore difficult to understand under current evolutionary paradigms. Finally, we note that as with AG Car in its cool phase, despite exceeding the HD limit, the properties of Cyg OB2 #12 imply that it lies below the Eddington limit – thus we conclude that the HD limit does not define a region of the HR diagram inherently inimical to the presence of massive stars.

Synthesis of Chromen[4,3-b]pyrrolidines by Intramolecular 1,3-Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.

Crash protection systems for handicapped school and transit bus occupants. Volume III: appendices A, B, C and D. Interim report.

National Highway Traffic Safety Administration, Washington, D.C.

Asiatic Art, VII century B.C.-XVIII century A.D., including sculpture in bronze & stone, ceramics, miniatures and textiles.

Exhibition and sale at the American Art Galleries, New York.

The complete confectioner, or, Housekeeper's guide to a simple and speedy method of understanding the whole art of confectionary : the various ways of preserving and candying, dry and liquid, all kinds of fruit, nuts, flowers, herbs, &c. And the method of keeping them fresh and fine all the year round; the different ways of clarifying sugar; with directions for making fruit pastes, bomboons, pastils, compotes, fruit ices, cream ices, marmalades, jellies, jams, cakes, puffs, biscuits, tarts, custards, cheesecakes, sweetmeats, fritters, creams, syllabubs, blanc-mange, flummeries, ornaments for grand entertainments, dragees, syrups of all kinds, nicknacks and trifles for desserts, strong cordials, oils, simple waters, milk punch that will keep 20 years, and all sorts of English wines. Also, the art of making artificial fruit, with the stalks in it, so as to resemble the natural fruit. To which are added, some bills of fare for desserts for private families /

Originally published under title: The compleat confectioner. Cf. Bitting, K.G. Gastronomic bib., p. 190.

Report to the President by the Emergency Board created June 23, 1948 by Executive order 9971 pursuant to Section 10 of the Railway Labor Act : to investigate and report upon a dispute between the Grand Trunk Western Railroad Co., Chesapeake and Ohio Railway Co., Wabash Railroad and the Ann Arbor Railroad Co. and certain of its employees represented by the National Maritime Union of America, N.M.B. cases A-2801, A-2802, A-2803, A-2804, Detroit, Michigan, July 20, 1948.

Signed: Robert G. Simmons, chairman, Thomas F. Gallagher, member, Joseph L. Miller, member.

East and west through fifteen centuries; being a general history from B.C. 44 to A.D. 1453,

No more published.

A B C de l'apiculture; encyclopédie de tout ce qui a rapport à l'abeille, miel, ruches, instruments, plantes mellifères, etc., résultats d'observations et d'expériences de milliers d'apiculteurs, contrôlées ensuite par un travail pratique dans nos propres ruchers.

p. 518-524 advertising.

L.M.B.C. memoirs on typical British marine plants and animals

Mode of access: Internet.

Las leyes de todos los reynos de Castilla abreuiadas y reduzidas en forma de Reportorio decisiuo por la orden del A.B.C. /

Portada a dos tintas con escudo y orla xilográficos.

El A.B.C. de la visión intuitiva ó principios de la visión relativamente á los tamaños /

Contiene: Parte 1º y Parte 2º

The history of Greece from its commencement to the close of the independence of the Greek nation;

The translators of v. 1-3 are not known; v. 4 was translated by Frederick Clarke, who revised the translation of v. 1-3.

The Roman empire : B. C. 29-A. D. 476 /

Includes index.