Abstract:
:If H denotes the classical Hilbert transform and Hu(x) = v(x), then the functions u(x) and v(x) are the values on the real axis of a pair of conjugate functions, harmonic in the upper half-plane. This note gives a generalization of the above concepts in which the Laplace equation Deltau = 0 is replaced by the Yukawa equation Deltau = mu(2)u and in which the Cauchy-Riemann equations have a corresponding generalization. This leads to a generalized Hilbert transform H(mu). The kernel function of this new transform is expressable in terms of the Bessel function K(0). The transform is of convolution type.
journal_name
Proc Natl Acad Sci U S Aauthors
Duffin RJdoi
10.1073/pnas.69.12.3677subject
Has Abstractpub_date
1972-12-01 00:00:00pages
3677-9issue
12eissn
0027-8424issn
1091-6490journal_volume
69pub_type
杂志文章abstract::Proteins of ribosomes from various stages of development in Dictyostelium discoideum were analyzed by two-dimensional polyacrylamide gel electrophoresis. Significant changes in protein composition were observed; the data demonstrate that cell differentiation in a eukaryotic system is accompanied by ribosome heterogene...
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.78.5.3083
更新日期:1981-05-01 00:00:00
abstract::Invading organisms may spread through local movements (giving rise to a diffusion-like process) and by long-distance jumps, which are often human-mediated. The local spread of invading organisms has been fit with varying success to models that couple local population growth with diffusive spread, but to date no quanti...
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.98.3.1095
更新日期:2001-01-30 00:00:00
abstract::Restriction site variation in DNA that encodes rRNA (rDNA) was surveyed among 714 offspring within 31 lineages (26 genotypes) of obligate asexually reproducing Taraxacum officinale (dandelions). Although clonal offspring are expected, plants with nonparental rDNA were produced from two parents that were themselves sib...
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.87.3.998
更新日期:1990-02-01 00:00:00
abstract::We have identified cis-acting regulatory elements in the 5' flanking region of the mouse alpha-fetoprotein (Afp) gene, using the expression of the bacterial gene for chloramphenicol acetyltransferase (CAT) in a transient expression assay. Tissue-specific enhancer activity was determined by transfection of mouse hepato...
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.83.21.8196
更新日期:1986-11-01 00:00:00
abstract::Humans routinely formulate plans in domains so complex that even the most powerful computers are taxed. To do so, they seem to avail themselves of many strategies and heuristics that efficiently simplify, approximate, and hierarchically decompose hard tasks into simpler subtasks. Theoretical and cognitive research has...
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.1414219112
更新日期:2015-03-10 00:00:00
abstract::The redox potentials of electron transfer proteins vary over a wide range, even when the type of redox center is the same. Rees [Proc. Natl. Acad. Sci. USA (1985) 82, 3082-3085] proposed that this variation of redox potential partly reflects the different net charges of the proteins, and he presented a linear correlat...
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.83.14.4998
更新日期:1986-07-01 00:00:00
abstract::Influenza is a lipid-enveloped, pleomorphic virus. We combine electron cryotomography and analysis of images of frozen-hydrated virions to determine the structural organization of filamentous influenza A virus. Influenza A/Udorn/72 virions are capsule-shaped or filamentous particles of highly uniform diameter. We show...
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.1002123107
更新日期:2010-06-08 00:00:00
abstract::Division of labor is fundamental to the success of all societies. The most striking examples are the physically polymorphic worker castes in social insects with clear morphological adaptations to different roles. These polymorphic worker castes have previously been thought to be a classic example of nongentically 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.1633701100
更新日期:2003-08-05 00:00:00
abstract::The unfolded protein response (UPR) is an evolutionarily conserved mechanism by which all eukaryotic cells adapt to the accumulation of unfolded proteins in the endoplasmic reticulum (ER). Inositol-requiring kinase 1 (IRE1) and PKR-related ER kinase (PERK) are two type I transmembrane ER-localized protein kinase recep...
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.0606480103
更新日期:2006-09-26 00:00:00
abstract::Proofreading mechanisms increase specificity in biochemical reactions by allowing for the dissociation of intermediate complexes. These mechanisms disrupt and reset the reaction to undo errors at the cost of increased time of reaction and free energy expenditure. Here, we draw an analogy between proofreading and micro...
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.1119911109
更新日期:2012-07-24 00:00:00
abstract::Several significant steps have been completed toward a general method for the site-specific incorporation of unnatural amino acids into proteins in vivo. An "orthogonal" suppressor tRNA was derived from Saccharomyces cerevisiae tRNA2Gln. This yeast orthogonal tRNA is not a substrate in vitro or in vivo for any Escheri...
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.96.9.4780
更新日期:1999-04-27 00:00:00
abstract::The mechanism of the proline-catalyzed aldol reaction has stimulated considerable debate, and despite limited experimental data, at least five different mechanisms have been proposed. Complementary to recent theoretical studies we have initiated an experimental program with the goal of clarifying some of the basic mec...
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.0307979101
更新日期:2004-04-20 00:00:00
abstract::Three proteins from cyanobacteria (KaiA, KaiB, and KaiC) can reconstitute circadian oscillations in vitro. At least three molecular properties oscillate during this reaction, namely rhythmic phosphorylation of KaiC, ATP hydrolytic activity of KaiC, and assembly/disassembly of intermolecular complexes among KaiA, KaiB,...
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.1002119107
更新日期:2010-08-17 00:00:00
abstract::In yeast meiosis, crossing-over between homologues is dependent upon double-strand breaks. We demonstrate that the occurrence of these breaks is independent of pairing between homologues by showing that they occur with normal frequency, timing, and position in the absence of a homologue. This observation supports mode...
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.91.25.11934
更新日期:1994-12-06 00:00:00
abstract::Id2 is a natural inhibitor of the basic helix-loop-helix transcription factors and the retinoblastoma tumor suppressor protein. Active Id2 prevents differentiation and promotes cell-cycle progression and tumorigenesis in the nervous system. A key event that regulates Id2 activity during differentiation is translocatio...
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.0600168103
更新日期:2006-03-28 00:00:00
abstract::Cell recognition molecules play a crucial role in the regulation of immune cells. We recently found that mast cells (MCs) express leukocyte recognition molecules, including ICAM-1 antigen, a natural ligand of LFA-1. We here report that interleukin 4 (IL-4), a pleiotropic cytokine and mast cell differentiation 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.88.8.3339
更新日期:1991-04-15 00:00:00
abstract::Population expansion in space, or range expansion, is widespread in nature and in clinical settings. Space competition among heterogeneous subpopulations during range expansion is essential to population ecology, and it may involve the interplay of multiple factors, primarily growth and motility of individuals. Struct...
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.1917789117
更新日期:2020-03-03 00:00:00
abstract::Selection is usually considered to be the dominant force controlling viral variation; the large population sizes suggest that deterministic population genetic models are appropriate. To investigate their validity for HIV, samples of env gene sequences were tested for departure from neutrality because of mutation-selec...
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.94.5.1862
更新日期:1997-03-04 00:00:00
abstract::Insertion mutations previously constructed within the proximal region of the yeast invertase signal sequence did not interfere with secretion or glycosylation of the enzyme. We now describe deletion mutations within the same signal sequence. Large deletions truncating the hydrophobic core of the signal peptide prevent...
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.83.14.5033
更新日期:1986-07-01 00:00:00
abstract::Schiff bases of the diamines 1,3-diaminopropane, putrescine, and cadaverine and the polyamines spermidine and spermine with pyridoxal or pyridoxal phosphate occur in human urine, as shown by gas chromatographic/mass spectrometric selected ion-monitoring techniques. By use of synthetic standards, procedures were devise...
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.76.12.6652
更新日期:1979-12-01 00:00:00
abstract::Glycogen synthase kinase 3 (GSK-3) is implicated in multiple biological processes including metabolism, gene expression, cell fate determination, proliferation, and survival. GSK-3 activity is inhibited through phosphorylation of serine 21 in GSK-3 alpha and serine 9 in GSK-3 beta. These serine residues of GSK-3 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.220413597
更新日期:2000-10-24 00:00:00
abstract::Phospholipase C-gamma1 (PLC-gamma1) contains two tandem Src homology 2 (SH2) domains. The NH(2)-terminal SH2 domain has been known to mediate the binding of PLC-gamma1 to receptor protein tyrosine kinases, which then activate PLC-gamma1 via phosphorylation at Y783. We now show that the phosphorylated Y783 residue (pY7...
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.0409590102
更新日期:2005-03-22 00:00:00
abstract::Transcriptional regulation of the human major histocompatibility complex class II genes requires at least two upstream elements, the X and Y boxes, located in the -50- to -150-base-pair region of all class II promoters. The DRA and DPB promoters contain phorbol ester-responsive elements overlapping the 3' side of thei...
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.88.10.4304
更新日期:1991-05-15 00:00:00
abstract::We have investigated the minimum extent of DNA sequence required for the attachment site of bacteriophage lambda to function in integrative recombination. A DNA fragment carrying the phage attachment site (attP) of bacteriophage lambda was trimmed, recloned, and tested for recombination proficiency. In order to recomb...
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.77.6.3220
更新日期:1980-06-01 00:00:00
abstract::Cholera vibrios produce a single polymeric protein that (i) causes hemagglutination; (ii) appears to participate in their attachment to gut epithelium; (iii) may mediate their detachment from gut epithelium; and (iv) is a protease that hydrolyzes fibronectin and mucin, cleaves lactoferrin, and nicks the A subunit of t...
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.80.4.1092
更新日期:1983-02-01 00:00:00
abstract::In addition to guiding proteins to defined genomic loci, DNA can act as an allosteric ligand that influences protein structure and activity. Here we compared genome-wide binding, transcriptional regulation, and, using NMR, the conformation of two glucocorticoid receptor (GR) isoforms that differ by a single amino acid...
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.1316235110
更新日期:2013-10-29 00:00:00
abstract::Several studies have suggested that introgressed Neandertal DNA was subjected to negative selection in modern humans. A striking observation in support of this is an apparent monotonic decline in Neandertal ancestry observed in modern humans in Europe over the past 45,000 years. Here, we show that this decline is an a...
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.1814338116
更新日期:2019-01-29 00:00:00
abstract::The region of human chromosome 22q11 is prone to rearrangements. The resulting chromosomal abnormalities are involved in Velo-cardio-facial and DiGeorge syndromes (VCFS and DGS) (deletions), "cat eye" syndrome (duplications), and certain types of tumors (translocations). As a prelude to the development of mouse models...
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.94.26.14608
更新日期:1997-12-23 00:00:00
abstract::Plants in dense vegetation compete for resources, including light, and optimize their growth based on neighbor detection cues. The best studied of such behaviors is the shade-avoidance syndrome that positions leaves in optimally lit zones of a vegetation. Although proximate vegetation is known to be sensed through a 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.1205437109
更新日期:2012-09-04 00:00:00
abstract::Shewanella species are renowned for their respiratory versatility, including their ability to respire poorly soluble substrates by using enzymatic machinery that is localized to the outside of the cell. The ability to engage in "extracellular respiration" to date has focused primarily on respiration of minerals. Here,...
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.0505959103
更新日期:2006-03-21 00:00:00