Abstract:
:The chronometric redshift-distance relation z = tan 2(1/2rho), where rho is the distance in radians in the Einstein metric, is derived by an elementary geometric analysis comparable to that in traditional analysis of the expanding universe model. The differential dTt of Einstein time evolution Tt through time t, as applied to the local Minkowski coordinates x, takes the form sec2(1/2t). At the point of observation t = rho, implying that for a sufficiently localized source, observed wave lengths are a factor of sec2(1/2rho) greater than the corresponding emitted wave lengths.
journal_name
Proc Natl Acad Sci U S Aauthors
Segal IEdoi
10.1073/pnas.90.23.11114keywords:
subject
Has Abstractpub_date
1993-12-01 00:00:00pages
11114-6issue
23eissn
0027-8424issn
1091-6490journal_volume
90pub_type
杂志文章abstract::The binding of thyroid hormone to the thyroid hormone receptor (TR) mediates important physiological effects. However, the transcriptional effects of TR mediated by the thyroid response element (TRE) cannot explain many actions of thyroid hormone. We postulate that TR can initiate rapid, non-TRE-mediated effects in th...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0601600103
更新日期:2006-09-19 00:00:00
abstract::Unlike tailed bacteriophages, which use a preformed tail for transporting their genomes into a host bacterium, the ssDNA bacteriophage ΦX174 is tailless. Using cryo-electron microscopy and time-resolved small-angle X-ray scattering, we show that lipopolysaccharides (LPS) form bilayers that interact with ΦX174 at an ic...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1716614114
更新日期:2017-12-26 00:00:00
abstract::The regional structure of fibrinogen was considered in reference to the terminal plasmin-cleavage fragments, D and E. By two independent approaches, a yield of two D and two E fragments was determined and this established the presence of two D and two E regions in each fibrinogen molecule. Immunochemically, it was sho...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.1.158
更新日期:1974-01-01 00:00:00
abstract::Some dinosaurs reached masses that were approximately 8 times those of the largest, ecologically equivalent terrestrial mammals. The factors most responsible for setting the maximal body size of vertebrates are resource quality and quantity, as modified by the mobility of the consumer, and the vertebrate's rate of ene...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0904000106
更新日期:2009-07-21 00:00:00
abstract::Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unp...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1819027116
更新日期:2019-09-03 00:00:00
abstract::We studied regional cerebral blood flow using the H2(15)O method while normal subjects performed four similar tasks involving three-letter word beginnings (stems). Prior to each task, subjects studied a list of words. Local blood flow was then monitored during a 40-sec period while subjects (i) silently viewed word st...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.5.1837
更新日期:1992-03-01 00:00:00
abstract::Understanding the molecular determinants of specificity in protein-protein interaction is an outstanding challenge of postgenome biology. The availability of large protein databases generated from sequences of hundreds of bacterial genomes enables various statistical approaches to this problem. In this context covaria...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0805923106
更新日期:2009-01-06 00:00:00
abstract::Methane seeps are widespread seafloor ecosystems shaped by the emission of gas from seabed reservoirs. The microorganisms inhabiting methane seeps transform the chemical energy in methane to products that sustain rich benthic communities around the gas leaks. Despite the biogeochemical relevance of microbial methane r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1421865112
更新日期:2015-03-31 00:00:00
abstract::The liver plays a key role in the regulation of circulating levels of low density lipoproteins (LDL) because it is both the site for the production of and the major organ for the degradation of this class of lipoproteins. In this study, the effects of feeding polyunsaturated or saturated triacylglycerols on receptor-d...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.13.4526
更新日期:1985-07-01 00:00:00
abstract::A shuttle vector plasmid that contains sequences from simian virus 40, pBR322, and a bacterial marker gene, galactokinase, has been constructed. After replication in cells permissive for virus progeny, plasmid DNA was introduced into a galactokinase-deficient bacterial strain and the relative frequency of colonies wit...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.10.3010
更新日期:1983-05-01 00:00:00
abstract::The liver provides for long-term energy needs of the body by converting excess carbohydrate into fat for storage. Insulin is one factor that promotes hepatic lipogenesis, but there is increasing evidence that glucose also contributes to the coordinated regulation of carbohydrate and fat metabolism in liver by mechanis...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0401516101
更新日期:2004-05-11 00:00:00
abstract::One of the factors required for the antiviral activity of the synthetic nucleoside, ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), is the ability of the molecule to adopt the substrate conformation specified by the enzyme for which it is a competitive inhibitor, inosine 5'-phosphate dehydrogenase (IM...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.12.4257
更新日期:1976-12-01 00:00:00
abstract::It is well known from Hardin's "Tragedy of the Commons" [Hardin G (1968) Science 162:1243-1248] that, if open access is allowed, overgrazing typically results. Hardin, and most authors of the subsequent literature, adopted a static view of the underlying ecosystem. Here we extend this tragedy of the commons to conside...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0706553104
更新日期:2007-09-11 00:00:00
abstract::The bacterial RsgA, a circularly permutated GTPase, whose GTPase activity is dependent on the 30S ribosomal subunit, is a late-stage ribosome biogenesis factor involved in the 30S subunit maturation. The role of RsgA is to release another 30S biogenesis factor, RbfA, from the mature 30S subunit in a GTP-dependent mann...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1104645108
更新日期:2011-08-09 00:00:00
abstract::Sulfoquinovose (SQ; 6-deoxy-6-sulfoglucose) is the polar head group of the plant sulfolipid SQ-diacylglycerol, and SQ comprises a major proportion of the organosulfur in nature, where it is degraded by bacteria. A first degradation pathway for SQ has been demonstrated recently, a "sulfoglycolytic" pathway, in addition...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1507049112
更新日期:2015-08-04 00:00:00
abstract::Bovine proinsulin has been crystallized under a variety of conditions at both neutral and acid pH. Microtechniques were employed with sample weights of about 200 mug and volumes of 5-20 mul. The crystalline preparations all differ from each other morphologically.X-ray photographs of one form, tetragonal bipyramids gro...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.66.4.1213
更新日期:1970-08-01 00:00:00
abstract::Cytochrome c peroxidase reacts with peroxide to form compound I, which contains an oxyferryl heme and an indolyl radical at Trp-191. The indolyl free radical has a half-life of several hours at room temperature, and this remarkable stability is essential for the catalytic function of cytochrome c peroxidase. To probe ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.23.11118
更新日期:1994-11-08 00:00:00
abstract::Three approaches were used to study hybridization of complementary oligodeoxynucleotides by nonradiative fluorescence resonance energy transfer. (i) Fluorescein (donor) and rhodamine (acceptor) were covalently attached to the 5' ends of complementary oligodeoxynucleotides of various lengths. Upon hybridization of the ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.23.8790
更新日期:1988-12-01 00:00:00
abstract::Peripheral inhibitory nerves are physiological regulators of the contractile behavior of visceral smooth muscles. One of the transmitters responsible for inhibitory neurotransmission has been reputed to be a purine, possibly ATP. However, the exact identity of this substance has never been verified. Here we show that ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0705510104
更新日期:2007-10-09 00:00:00
abstract::Vertebrate dentitions are extraordinarily diverse in both morphology and regenerative capacity. The teleost order Tetraodontiformes exhibits an exceptional array of novel dental morphologies, epitomized by constrained beak-like dentitions in several families, i.e., porcupinefishes, three-toothed pufferfishes, ocean su...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1702909114
更新日期:2017-05-30 00:00:00
abstract::The mitochondrial trifunctional protein (TFP) catalyzes three reactions in the fatty acid β-oxidation process. Mutations in the two TFP subunits cause mitochondrial trifunctional protein deficiency and acute fatty liver of pregnancy that can lead to death. Here we report a 4.2-Å cryo-electron microscopy α2β2 tetrameri...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1801252115
更新日期:2018-07-03 00:00:00
abstract::Bub1 is a kinase believed to function primarily in the mitotic spindle checkpoint. Mutation or aberrant Bub1 expression is associated with chromosomal instability, aneuploidy, and human cancer. We now find that targeting Bub1 by RNAi or simian virus 40 (SV40) large T antigen in normal human diploid fibroblasts results...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0703164104
更新日期:2007-05-15 00:00:00
abstract::To initiate class switch recombination (CSR) activation-induced cytidine deaminase (AID) induces staggered nick cleavage in the S region, which lies 5' to each Ig constant region gene and is rich in palindromic sequences. Topoisomerase 1 (Top1) controls the supercoiling of DNA by nicking, rotating, and religating one ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0911879106
更新日期:2009-12-29 00:00:00
abstract::Autophagy is responsible for nonspecific, bulk degradation of cytoplasmic components. Recent work has revealed also that there is specific, autophagic degradation of polyubiquitinated protein aggregates, whose buildup occurs during neurodegenerative disease. Here, we report that simple mono-ubiquitination of normally ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0810611105
更新日期:2008-12-30 00:00:00
abstract::Domesticated animals formed an important element of farming practices in prehistoric Britain, a fact revealed through the quantity and variety of animal bone typically found at archaeological sites. However, it is not known whether the ruminant animals were raised purely for their tissues (e.g., meat) or alternatively...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0335955100
更新日期:2003-02-18 00:00:00
abstract::We have used a motif-based structural search method to identify structural homologs of the hormone binding domains of the nuclear receptors from among a set of known protein structures and have found the closest similarity with members of the subtilisin-like serine proteases. These proteins consist of an open twisted ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.21.9949
更新日期:1993-11-01 00:00:00
abstract::We have constructed 26-amino acid transmembrane proteins that specifically transform cells but consist of only two different amino acids. Most proteins are long polymers of amino acids with 20 or more chemically distinct side-chains. The artificial transmembrane proteins reported here are the simplest known proteins w...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1514230112
更新日期:2015-08-25 00:00:00
abstract::In the central nervous system, myelin proteolipid protein isoforms (PLP and DM20) play an essential structural role in myelination. It has been shown in several species that myelination is impaired by molecular defects resulting from single base mutations in the PLP gene. We have used DNA amplification by polymerase c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.17.7562
更新日期:1991-09-01 00:00:00
abstract::In 2005 four outstanding multiple burials were discovered near Eulau, Germany. The 4,600-year-old graves contained groups of adults and children buried facing each other. Skeletal and artifactual evidence and the simultaneous interment of the individuals suggest the supposed families fell victim to a violent event. In...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.0807592105
更新日期:2008-11-25 00:00:00
abstract::Malaria merozoite invasion of human erythrocytes depends on recognition of specific erythrocyte surface receptors by parasite ligands. Plasmodium vivax merozoite invasion is totally dependent on the recognition of the Duffy blood group antigen by the parasite ligand Duffy-binding protein (DBP). Receptor recognition by...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0405421101
更新日期:2004-11-02 00:00:00