Abstract:
:Microstructural, δ(13)C isotope and C/N ratio investigations were conducted on excavated material from the black Younger Dryas boundary in Lommel, Belgium, aiming for a characterisation of the carbon content and structures. Cubic diamond nanoparticles are found in large numbers. The larger ones with diameters around or above 10 nm often exhibit single or multiple twins. The smaller ones around 5 nm in diameter are mostly defect-free. Also larger flake-like particles, around 100 nm in lateral dimension, with a cubic diamond structure are observed as well as large carbon onion structures. The combination of these characteristics does not yield unique evidence for an exogenic impact related to the investigated layer.
journal_name
Proc Natl Acad Sci U S Aauthors
Tian H,Schryvers D,Claeys Pdoi
10.1073/pnas.1007695108subject
Has Abstractpub_date
2011-01-04 00:00:00pages
40-4issue
1eissn
0027-8424issn
1091-6490pii
1007695108journal_volume
108pub_type
杂志文章abstract::Interleukin 10 (IL-10) inhibits interferon gamma-induced macrophage activation for cytotoxicity against larvae of the human parasite Schistosoma mansoni by suppressing production of the toxic effector molecule nitric oxide (NO). In this study, the mechanism of IL-10 action was identified as inhibition of endogenous tu...
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.89.18.8676
更新日期:1992-09-15 00:00:00
abstract::Membrane lipids were once thought to be homogenously distributed in the 2D surface of a membrane, but the lipid raft theory suggests that cholesterol and sphingolipids partition away from other membrane lipids. Lipid raft theory further implicates these cholesterol-rich domains in many processes such as signaling 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.0631608100
更新日期:2003-05-13 00:00:00
abstract::HIV type 1 (HIV-1) specifically uses host cell tRNALys-3 as a primer for reverse transcription. The 3' 18 nucleotides of this tRNA are complementary to a region on the HIV RNA genome known as the primer binding site (PBS). HIV-1 has a strong preference for maintaining a lysine-specific PBS in vivo, and viral genomes 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.94.25.13530
更新日期:1997-12-09 00:00:00
abstract::Grasslands cover more than 20% of the Earth's terrestrial surface, and their rise to dominance is one of the most dramatic events of biome evolution in Earth history. Grasses possess two main photosynthetic pathways: the C(3) pathway that is typical of most plants and a specialized C(4) pathway that minimizes photores...
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.0909672107
更新日期:2010-02-09 00:00:00
abstract::Control over the fluorescence of supramolecular assemblies is crucial for the development of chemosensors and light-emitting materials. Consequently, the postsynthetic modification of supramolecular structures via host-guest interactions has emerged as an efficient strategy in recent years that allows the facile tunin...
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.1702510114
更新日期:2017-03-21 00:00:00
abstract::The mitochondria are the major source of chronic oxidative stress, which has been implicated in the aging process. Along with other cellular changes, aged cells accumulate mutations in both their nuclear and mitochondrial genomes, and they contain increased amounts of oxidatively damaged mutagenic bases such as 7,8-di...
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.1932854100
更新日期:2003-09-16 00:00:00
abstract::Mutations at the mouse limb deformity (ld) locus result in defects of growth and patterning of the limb and kidney during embryonic development. The gene responsible for this phenotype is large and complex, with the capacity to generate a number of alternatively spliced messenger RNA transcripts encoding nuclear prote...
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.90.12.5554
更新日期:1993-06-15 00:00:00
abstract::A species of Rhodopseudomonas that grows under strict anaerobic conditions in the dark and requires CO was isolated from lake and pond sediments. Although anaerobic growth in the dark occurs in a chemically defined mineral medium with CO as the only carbon and energy source, growth is stimulated by adding trypticase. ...
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.73.9.3298
更新日期:1976-09-01 00:00:00
abstract::The vascular endothelial growth factor (VEGF) family has recently expanded by the identification and cloning of three additional members, namely VEGF-B, VEGF-C, and VEGF-D. In this study we demonstrate that VEGF-B binds selectively to VEGF receptor-1/Flt-1. This binding can be blocked by excess VEGF, indicating that 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.95.20.11709
更新日期:1998-09-29 00:00:00
abstract::Glucagon and insulin are first detectable at the onset of rat pancreas organogenesis. Initially, the specific activity of glucagon is approximately 100-fold higher than that of insulin. At this early stage, endocrine storage granules, similar to alpha granules, are identifiable in electron micrographs. The granule cha...
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.70.12.3478
更新日期:1973-12-01 00:00:00
abstract::Eradication of an invasive species can provide significant environmental, economic, and social benefits, but eradication programs often fail. Constant and careful monitoring improves the chance of success, but an invasion may seem to be in decline even when it is expanding in abundance or spatial extent. Determining 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.1216146110
更新日期:2013-08-13 00:00:00
abstract::Macrophage migration inhibitory factor (MIF) is a mediator of host immunity and functions as a high, upstream activator of cells within the innate and the adaptive immunological systems. Recent studies have suggested a potentially broader role for MIF in growth regulation because of its ability to antagonize p53-media...
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.1533295100
更新日期:2003-08-05 00:00:00
abstract::A controversial topic in the recent climate modeling literature is the fashion in which metastable low-frequency regimes in the atmosphere occur despite nearly Gaussian statistics for these planetary waves. Here a simple 57-mode paradigm model for such metastable atmospheric regime behavior is introduced and analyzed ...
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.0602641103
更新日期:2006-05-30 00:00:00
abstract::Double fertilization is a key innovation for the evolutionary success of angiosperms by which the two fertilized female gametes, the egg cell and central cell, generate the embryo and endosperm, respectively. The female gametophyte (embryo sac) enclosed in the sporophyte is derived from a one-celled haploid cell linea...
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.1909465117
更新日期:2020-03-17 00:00:00
abstract::Experimental systemic lupus erythematosus (SLE) can be induced in naive mice by immunization with a murine monoclonal anti-DNA antibody (mAb), 5G12, that bears a major idiotype designated 16/6 Id. Strain-dependent differences were observed in the proliferative responses of lymph node cells of mice immunized with two p...
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.94.9.4620
更新日期:1997-04-29 00:00:00
abstract::We examine how the polypeptide chain in protein crystal structures exploits the multivalent hydrogen-bonding potential of bound water molecules. This shows that multiple interactions with a single water molecule tend to occur locally along the chain. A distinctive internal-coordinate representation of the local water-...
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.92.16.7600
更新日期:1995-08-01 00:00:00
abstract::These studies sought to determine if neurons in the estrogen receptor-alpha knockout (ERalphaKO) mouse brain concentrated 16alpha-[125I]iodo-11beta-methoxy-17beta-estradiol (125I-estrogen), and if so, whether estrogen binding augmented the expression of progesterone receptor (PR) mRNA. Mice were injected with 125I-est...
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.94.20.11008
更新日期:1997-09-30 00:00:00
abstract::The mutation spectrum induced by the widely used antitumor drug cis-diamminedichloroplatinum(II) (cis-DDP) showed that cisDDP[d(ApG)] adducts, although they account for only 25% of the lesions formed, are approximately 5 times more mutagenic than the major GG adduct. We report the construction of vectors bearing a sin...
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.87.16.6087
更新日期:1990-08-01 00:00:00
abstract::Precise genome editing is a valuable tool to study gene function in model organisms. Prime editing, a precise editing system developed in mammalian cells, does not require double-strand breaks or donor DNA and has low off-target effects. Here, we applied prime editing for the model organism Drosophila melanogaster 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.2021996118
更新日期:2021-01-05 00:00:00
abstract::Epstein-Barr virus (EBV), an oncogenic herpesvirus, encodes two small RNAs (EBERs) that are expressed at high levels during latent transformation of human B lymphocytes. Here we report that a 15-kDa cellular protein called EAP (for EBER associated protein), previously shown to bind EBER1, is in fact the ribosomal prot...
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.91.8.3463
更新日期:1994-04-12 00:00:00
abstract::Ionizing radiation has been used to selectively separate the circadian oscillator function of the eye of Aplysia from some of its other functions--synchronous compound action potential (CAP) generation, the light response, synaptic transmission between photoreceptors and output neurons, and the bursting pacemaker mech...
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.77.9.5542
更新日期:1980-09-01 00:00:00
abstract::The L-A double-stranded RNA virus of Saccharomyces cerevisiae makes a gag-pol fusion protein by a -1 ribosomal frameshift. The pol amino acid sequence includes consensus patterns typical of the RNA-dependent RNA polymerases (EC 2.7.7.48) of (+) strand and double-stranded RNA viruses of animals and plants. We have carr...
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.89.6.2185
更新日期:1992-03-15 00:00:00
abstract::Nitrogen limitation imposes a major transition in the lifestyle of nondiazotrophic cyanobacteria that is controlled by a complex interplay of regulatory factors involving the pervasive signal processor PII Immediately upon nitrogen limitation, newly fixed carbon is redirected toward glycogen synthesis. How the metabol...
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.2019988118
更新日期:2021-02-09 00:00:00
abstract::Pathologic ocular neovascularization commonly causes blindness. It is critical to identify the factors altered in pathologically proliferating versus normally quiescent vessels to develop effective targeted therapeutics. MicroRNAs regulate both physiological and pathological angiogenesis through modulating expression ...
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.1508426112
更新日期:2015-09-29 00:00:00
abstract::The complete coding region of maize transposable element Ac and truncated but active derivatives of it were placed under the control of promoters of different strength and tested for the ability to excise transposable element Ds from a beta-glucuronidase reporter gene in a cotransfection assay in Petunia protoplasts. ...
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.89.12.5552
更新日期:1992-06-15 00:00:00
abstract::The opposite slopes of "Evolution Canyon" in Israel have served as a natural model system of adaptation to a microclimate contrast. Long-term studies of Drosophila melanogaster populations inhabiting the canyon have exhibited significant interslope divergence in thermal and drought stress resistance, candidate genes, ...
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.1321533111
更新日期:2013-12-24 00:00:00
abstract::When assembled into 13--19S particles, the reovirus nonstructural protein sigma-NS selectively binds single-stranded RNAs. Sedimentation analyses combined with binding to nitrocellulose membrane filters showed that 1--2 pmol of reovirus mRNAs from the large, medium, or small size classes saturated in vitro the binding...
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.79.11.3457
更新日期:1982-06-01 00:00:00
abstract::The region of the murine major histocompatibility complex (MHC) between the Pb (A beta 3) and Ob (A beta 2) genes controls the expression of an intracellular complex named the LMP (low molecular weight polypeptide) complex. DNA probes for at least seven different genes mapping to this region were isolated. These hybri...
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.88.12.5197
更新日期:1991-06-15 00:00:00
abstract::Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) was found to increase the adherence of purified peripheral blood monocytes to plastic surfaces and to monolayers of human umbilical vein endothelial cells. With plastic surfaces as a model 9-hr culture with GM-CSF was necessary for enhancement...
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.86.18.7169
更新日期:1989-09-01 00:00:00
abstract::The nucleotide sequence of a 1,163-base-pair fragment that encodes the entire thyA gene of Escherichia coli K-12 was determined. The strategy involved sequence determination of both DNA strands by using overlapping deletions that had been generated in vitro from the two ends of the fragment with BAL-31 nuclease. The 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.80.16.4914
更新日期:1983-08-01 00:00:00