Abstract:
:The multiplication in gases of ionization electrons, by the effect of the electric fields between parallel electrodes, leads to the emission of light from the molecules excited in the avalanche process. The optical imaging of this light, with intensifiers, on charge-coupled devices permits the localization, in the gaseous volume, of the entrance points of the beta-particles emitted by radioactive compounds placed close to or at the cathode electrode. Thin slices of anatomical samples labeled with 3H show detailed structures 30 microns in size. Gels carrying 32P or 35S are imaged with accuracies of the order of 0.5 mm (full width at half maximum). In comparison with photographic emulsion, the gain in time for data taking is close to a factor of 100, with the advantage of linearity and wider dynamic range in the intensity measurement and a greatly improved signal-to-noise ratio.
journal_name
Proc Natl Acad Sci U S Aauthors
Charpak G,Dominik W,Zaganidis Ndoi
10.1073/pnas.86.6.1741subject
Has Abstractpub_date
1989-03-01 00:00:00pages
1741-5issue
6eissn
0027-8424issn
1091-6490journal_volume
86pub_type
杂志文章abstract::Plant soil specialists contribute greatly to global diversity; however, the ecoevolutionary forces responsible for generating this diversity are poorly understood. We integrate molecular phylogenies with descriptive and experimental ecological data, creating a powerful framework with which to elucidate forces driving ...
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.1409242111
更新日期:2014-10-21 00:00:00
abstract::Adeno-associated virus (AAV) vector delivery of an Apaf-1-dominant negative inhibitor was tested for its antiapoptotic effect on degenerating nigrostriatal neurons in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease. The wild-type caspase recruitment domain of Apaf-1 was used as a dom...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2001-09-11 00:00:00
abstract::All science has uncertainty. Unless that uncertainty is communicated effectively, decision makers may put too much or too little faith in it. The information that needs to be communicated depends on the decisions that people face. Are they (i) looking for a signal (e.g., whether to evacuate before a hurricane), (ii) c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2014-09-16 00:00:00
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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.0509623102
更新日期:2006-01-10 00:00:00
abstract::The amphiphilic fluorescent styryl pyridinium dyes FM1-43 and FM4-64 are used to probe activity-dependent synaptic vesicle cycling in neurons. Cultured astrocytes can internalize FM1-43 and FM4-64 inside vesicles but their uptake is insensitive to the elevation of cytosolic calcium (Ca(2+)) concentration and the under...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2009-12-22 00:00:00
abstract::This study presents, to our knowledge, the first on-line measurement of acetylcholinesterase (AcChoEase) release from brain tissue. It is now well established that a soluble form of the enzyme is released from central nervous system neurons, and it has been proposed on indirect grounds that such release may occur not ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1987-05-01 00:00:00
abstract::The cytokine IFN-γ is a critical regulator of immune system development and function. Almost all leukocytes express the receptor for IFN-γ, yet each cell type elicits a different response to this cytokine. Cell type-specific effects of IFN-γ make it difficult to predict the outcomes of the systemic IFN-γ blockade and ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2018-11-06 00:00:00
abstract::Chromopeptides were prepared by proteolytic digestion of phytochrome (far-red absorbing form, P(fr)) and of phycocyanin. The phycocyanobilin peptide, the chromophore of which is Z,Z,Z-configurated, was modified to the Z,Z,E isomeric chromophore. It has been demonstrated earlier that the P(fr) chromopeptide and the Z,Z...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-10-01 00:00:00
abstract::Of two closely related species of geese, one, the greylag goose, lives in the Indian plains all year round, while the other, the bar-headed goose, lives at the Tibetan lakes and migrates across the Himalayas to winter in India. Another species, the Andean goose, lives in the High Andes all year round. Possession of a ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1991-08-01 00:00:00
abstract::Future nuclear arms reduction efforts will require technologies to verify that warheads slated for dismantlement are authentic without revealing any sensitive weapons design information to international inspectors. Despite several decades of research, no technology has met these requirements simultaneously. Recent wor...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2018-04-24 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
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更新日期:2015-08-04 00:00:00
abstract::Single-molecule manipulation techniques reveal that stretching unravels individually folded domains in the muscle protein titin and the extracellular matrix protein tenascin. These elastic proteins contain tandem repeats of folded domains with beta-sandwich architecture. Herein, we propose by stretching two model sequ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2000-06-20 00:00:00
abstract::Regulation of translation is critical for maintaining cellular protein levels, and thus protein homeostasis. The conserved RNA-binding protein CsrA (also called RsmA; for carbon storage regulator and regulator of secondary metabolism, respectively; hereafter called CsrA) represents a well-characterized example of regu...
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.1602425113
更新日期:2016-09-06 00:00:00
abstract::The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a funct...
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.1500107112
更新日期:2015-06-09 00:00:00
abstract::As a second-order nonlinear optical process, sum-frequency generation is highly surface-specific and accordingly has been developed into a very powerful and versatile surface spectroscopic tool. It has found many unique applications in different disciplines and thus provided many exciting new research opportunities in...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.93.22.12104
更新日期:1996-10-29 00:00:00
abstract::Poly(A)-containing HeLa cell mRNA prepared from cells labeled with [methyl-(3)H]methionine or [(32)P]phosphate was found to contain a variety of methylated, blocked 5'-terminal structures of two general types: m(7)GpppN(7)-Np and m(7)GpppN(m)-N(m)-Np. In addition, about one-third of the [(3)H]methyl label was present ...
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.72.5.1904
更新日期:1975-05-01 00:00:00
abstract::The photoaffinity labeling agent 5-azidoindole-3-acetic acid, an analog of the endogenous plant hormone indole-3-acetic acid (an auxin), was used to identify indole-3-acetic acid-binding proteins in maize. Two peptides with subunit molecular masses of 24 and 22 kilodaltons are specifically labeled in a saturable manne...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1989-08-01 00:00:00
abstract::Proliferating-cell nuclear antigen (PCNA) mediates the replication of simian virus 40 (SV40) DNA by reversing the effects of a protein that inhibits the elongation reaction. Two other protein fractions, activator I and activator II, were also shown to play important roles in this process. We report that activator II i...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1989-10-01 00:00:00
abstract::We demonstrate theoretically and experimentally the spontaneous clustering of solitons in partially coherent wavefronts during the final stages of pattern formation initiated by modulation instability and noise. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2002-04-16 00:00:00
abstract::Sex determination in mammals is governed by antagonistic interactions of two genetic pathways, imbalance in which may lead to disorders/differences of sex development (DSD) in human. Among 46,XX individuals with testicular DSD (TDSD) or ovotesticular DSD (OTDSD), testicular tissue is present in the gonad. Although the...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2006-11-07 00:00:00
abstract::New neurons are continuously generated in restricted regions of the adult mammalian brain. Although these adult-born neurons have been shown to receive synaptic inputs, little is known about their synaptic outputs. Using retrovirus-mediated birth-dating and labeling in combination with serial section electron microsco...
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.0806658105
更新日期:2008-09-16 00:00:00
abstract::Semaphorin 4D (sema4D; CD100) is an integral membrane protein and the ligand for two receptors, CD72 and plexin-B1. Soluble sema4D has been shown to evoke angiogenic responses from endothelial cells and impair monocyte migration, but the origin of soluble sema4D, particularly at sites of vascular injury, has been uncl...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2007-01-30 00:00:00
abstract::All proteins of this world are constructed in compliance with the same rule. Accordingly, two totally unrelated proteins, on the average, share 30 identical tripeptides, two tetrapeptides, and one pentapeptide per 500 residues. With this in mind, the 221-residue-long influenza virus hemagglutinin II (IVHA-II), as a re...
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.88.8.3065
更新日期:1991-04-15 00:00:00
abstract::The rate of derepressed synthesis of a membrane protein required for lactose transport (M protein) by Escherichia coli is increased in response to increased gene dosage to the same extent as the rates of synthesis of beta-galactosidase and galactoside acetylase. However, elevated gene dosage does not increase beta-gal...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1969-07-01 00:00:00
abstract::The three members of the Brn-3 family of POU domain transcription factors are found in highly restricted sets of central nervous system neurons. Within the retina, these factors are present only within subsets of ganglion cells. We show here that in the developing mouse retina, Brn-3b protein is first observed in pres...
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.93.9.3920
更新日期:1996-04-30 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::To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. 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.1112750109
更新日期:2012-08-07 00:00:00
abstract::Due to the small size of a nanoconfinement, the property of water contained inside is rather challenging to probe. Herein, we measured the amount of water molecules released during the folding of individual G-quadruplex and i-motif structures, from which water activities are estimated in the DNA nanocages prepared by ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2018-09-18 00:00:00
abstract::Glutamate transport by the excitatory amino acid carrier EAAC1 is known to be reversible. Thus, glutamate can either be taken up into cells, or it can be released from cells through reverse transport, depending on the electrochemical gradient of the co- and countertransported ions. However, it is unknown how fast and ...
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.0704570104
更新日期:2007-11-13 00:00:00