Abstract:
:For length and area, a central fact is that the value of the length of a curve or the area of a surface, as given by the Lebesgue theory, is at least as great as that given by the classical formula, whenever the latter has meaning. This is now found not to be valid in higher dimensions. We give an example of a continuous mapping of the unit cube into itself for which the value given by the formula exceeds the three-dimensional Lebesgue area of the corresponding suface.
journal_name
Proc Natl Acad Sci U S Aauthors
Goffman Cdoi
10.1073/pnas.63.1.38subject
Has Abstractpub_date
1969-05-01 00:00:00pages
38-9issue
1eissn
0027-8424issn
1091-6490journal_volume
63pub_type
杂志文章abstract::Lipoxin B (LXB) was prepared by incubation of (15S)-15-hydroperoxy-5,8,11-cis-13-trans-icosatetraenoic acid (15-HPETE) with human leukocytes. Comparison with a number of trihydroxyicosatetraenes prepared by total synthesis showed that biologically derived LXB is (5S,14R,15S)-5,14,15-trihydroxy-6,10,12-trans-8-cis-icos...
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.83.7.1983
更新日期:1986-04-01 00:00:00
abstract::Intracellular Ca(2+) release in many types of cells is mediated by ryanodine receptor Ca(2+) release channels (RyRCs) that are assembled into two-dimensional paracrystalline arrays in the endoplasmic/sarcoplasmic reticulum. However, the in situ operating mechanism of the RyRC array is unknown. Here, we found that 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.0306157101
更新日期:2004-03-16 00:00:00
abstract::Studies in rodents and nonhuman primates have linked the activity of N-methyl-D-aspartate (NMDA) receptors within the hippocampus to animals' performance on memory-related tasks. However, whether these receptors are similarly essential for human memory is still an open question. Here we present evidence suggesting tha...
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.96.21.12085
更新日期:1999-10-12 00:00:00
abstract::The HER2 gene encodes a cell-surface glycoprotein with extensive homology to the epidermal growth factor receptor. Recently it was found to be amplified in about 30% of primary human breast malignancies. In experiments designed to assess the role of the HER2 gene in oncogenesis, we found that overexpression of unalter...
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.84.20.7159
更新日期:1987-10-01 00:00:00
abstract::The Sleeping Beauty (SB) transposon mutagenesis screen is a powerful tool to facilitate the discovery of cancer genes that drive tumorigenesis in mouse models. In this study, we sought to identify genes that functionally cooperate with sonic hedgehog signaling to initiate medulloblastoma (MB), a tumor of the cerebellu...
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.1318639110
更新日期:2013-11-12 00:00:00
abstract::Regulated proteolysis is required to execute many cellular programs. In Caulobacter crescentus, timely degradation of the master regulator CtrA by ClpXP protease is essential for cell-cycle progression and requires the colocalization of CtrA and RcdA. Here, we establish a biochemical framework to understand regulated ...
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.0701776104
更新日期:2007-04-17 00:00:00
abstract::With high-dimensional data, variable-by-variable statistical testing is often used to select variables whose behavior differs across conditions. Such an approach requires adjustment for multiple testing, which can result in low statistical power. A two-stage approach that first filters variables by a criterion indepen...
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.0914005107
更新日期:2010-05-25 00:00:00
abstract::Pair-bond formation depends vitally on neuromodulatory signaling within the nucleus accumbens, but the neuronal dynamics underlying this behavior remain unclear. Using 1-photon in vivo Ca2+ imaging in monogamous prairie voles, we found that pair bonding does not elicit differences in overall nucleus accumbens Ca2+ act...
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.1917287117
更新日期:2020-05-19 00:00:00
abstract::ErbB2 interacting protein (Erbin) is a widely expressed protein and participates in inhibition of several intracellular signaling pathways. Its mRNA has been found to be present in relatively high levels in the heart. However, its physiological role in the heart has not been explored. In the present work, we elucidate...
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.1320350111
更新日期:2014-04-22 00:00:00
abstract::A striking feature of the human genome is the dearth of CpG dinucleotides (CpGs) interrupted occasionally by CpG islands (CGIs), regions with relatively high content of the dinucleotide. CGIs are generally associated with promoters; genes, whose promoters are especially rich in CpG sequences, tend to be expressed in m...
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.0510310103
更新日期:2006-01-31 00:00:00
abstract::A human liver cDNA library was screened by colony hybridization with a bovine factor X cDNA probe. Three of the positive plasmids contained overlapping DNA that coded for most of human factor X mRNA. DNA sequence analysis of these three clones allowed the prediction of the complete amino acid sequence of plasma factor...
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.82.11.3591
更新日期:1985-06-01 00:00:00
abstract::Many changes have been described in the brains of Alzheimer's disease (AD) patients, including loss of neurons and formation of senile plaques and neurofibrillary tangles. The molecular mechanisms underlying these pathologies are unclear. Northern blot, dot-blot, and reverse transcription-coupled PCR analyses have dem...
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.95.16.9620
更新日期:1998-08-04 00:00:00
abstract::Mutations in the visA gene of Escherichia coli cause the mutant bacteria to die upon illumination with visible light. We confirmed genetically that the visA gene is a structural gene for ferrochelatase (protoheme ferro-lyase, EC 4.99.1.1). Since other mutations in the genes involved in the biosynthesis of heme can cur...
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.88.23.10520
更新日期:1991-12-01 00:00:00
abstract::The complexed (ribosome-bearing) membrane fraction of Bacillus subtilis contains several proteins (CM-proteins) that are virtually absent from the ribosome-free fraction and hence might be components of the apparatus of protein secretion. We have determined, by trypsin digestion and by labeling with a nonpenetrating 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.80.11.3287
更新日期:1983-06-01 00:00:00
abstract::The embryonic sites in which progenitors of the hematopoietic lineages first emerge are ideal regions to characterize both the cells and environment needed to initiate blood cell development. For a number of years both the murine yolk sac and embryo have been recognized to contain progenitors of B lymphocytes. However...
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.90.14.6429
更新日期:1993-07-15 00:00:00
abstract::The classic anthropological hypothesis known as the "obstetrical dilemma" is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution. The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapte...
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.1205282109
更新日期:2012-09-18 00:00:00
abstract::Destruction of mitotic cyclins by ubiquitin-dependent proteolysis is required for cells to complete mitosis and enter interphase of the next cell cycle. In clam eggs, this process is catalyzed by a cyclin-selective ubiquitin carrier protein, E2-C, and the cyclosome/anaphase promoting complex (APC), a 20S particle cont...
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.94.6.2362
更新日期:1997-03-18 00:00:00
abstract::One of the enduring problems in the study of social evolution has been to understand how cooperation can be maintained in the presence of freeloaders, individuals that take advantage of the more cooperative members of groups they are eager to join. The freeloader problem has been particularly troublesome when groups 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.212408299
更新日期:2002-10-29 00:00:00
abstract::Insig-1 and -2 are closely related proteins of the endoplasmic reticulum (ER) that block proteolytic activation of sterol regulatory element-binding proteins (SREBPs), transcription factors that activate the synthesis of cholesterol and fatty acids in liver and other organs. When cellular cholesterol levels are high, ...
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.0130116100
更新日期:2003-03-18 00:00:00
abstract::Microtubule-associated protein 2 kinase (MAP kinase), which exists in several forms, is a protein serine/threonine kinase that participates in a growth factor-activated protein kinase cascade in which it activates a ribosomal protein S6 kinase (pp90rsk) while being regulated itself by a cytoplasmic factor (MAP kinase ...
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.88.14.6142
更新日期:1991-07-15 00:00:00
abstract::The 89-kDa cell surface glycoprotein, P3.58, is detectable on advanced human melanomas in situ but not on benign melanocytes or early melanomas. cDNA cloning of P3.58 from melanoma cells was accomplished by screening a lambda zap expression vector library with monoclonal antibodies produced against the denatured antig...
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.86.2.641
更新日期:1989-01-01 00:00:00
abstract::The role of cell surface immunoglobulin in helper T-cell-dependent B-cell activation was analyzed using a B-cell lymphoma, CH12, with known antigen specificity and activation properties similar to those of a resting B cell. Two sources of helper T cells were used, both selected such that they interact with H-2-encoded...
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.81.8.2466
更新日期:1984-04-01 00:00:00
abstract::Clostridium difficile, a causative agent of antibiotic-associated diarrhea and its potentially lethal form, pseudomembranous colitis, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The level of toxin production appears to be critical for determining the seve...
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.101126598
更新日期:2001-05-08 00:00:00
abstract::T cells are activated physiologically by triggering the T-cell receptor-CD3 complex. There is evidence that invariant accessory molecules on the T-cell membrane (CD8 and CD4) are involved in the major histocompatibility complex-restricted recognition process. Moreover, binding and crosslinking of these accessory molec...
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.85.24.9689
更新日期:1988-12-01 00:00:00
abstract::A major question in plant physiology is how the large amount of sucrose made in leaves is transported to the rest of the plant. Although physiological, biochemical, and anatomical investigations have been performed in this field, to date there have been very few genetic studies. Using a reverse genetic screen, we have...
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.250473797
更新日期:2000-12-05 00:00:00
abstract::Despite its theoretical prominence and sound principles, integrated pest management (IPM) continues to suffer from anemic adoption rates in developing countries. To shed light on the reasons, we surveyed the opinions of a large and diverse pool of IPM professionals and practitioners from 96 countries by using structur...
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.1312693111
更新日期:2014-03-11 00:00:00
abstract::We have isolated a 2.7-kilobase rat liver cDNA clone that contains the entire 544-amino acid coding sequence for matrin F/G. This protein has previously been localized to the internal, fibrogranular areas of the nuclear matrix and shown to bind to DNA on nitrocellulose blots. The predicted amino acid sequence from 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.88.14.6186
更新日期:1991-07-15 00:00:00
abstract::Diabetes is now the most common cause of progressive kidney failure leading to dialysis or transplantation. The central pathological feature of diabetic nephropathy is accumulation of extracellular matrix within the glomeruli. The factors in the diabetic milieu responsible for extracellular matrix accumulation are not...
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.90.5.1814
更新日期:1993-03-01 00:00:00
abstract::Parvalbumin (PV) is a Ca2+-binding protein found only in vertebrates. It is postulated to serve as a soluble relaxing factor in fast mammalian muscle. We have isolated a rat PV cDNA clone and used this as a probe to examine changes in PV mRNA during muscle and brain development. A cDNA library was constructed in PUC8/...
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.82.5.1414
更新日期:1985-03-01 00:00:00
abstract::The presence of an amino acid other than aspartic acid at position 57 of the HLA-DQ beta chain (non-Asp-57) is highly associated with susceptibility to insulin-dependent diabetes mellitus (IDDM), whereas an aspartic acid at this position (Asp-57) appears to confer resistance to the disease. We hypothesize that the 30-...
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.87.19.7370
更新日期:1990-10-01 00:00:00